The president's prime-time speech included false statements about the price of gas, the number of new power plants and the cost of electricity.

A growth engine for the economy is becoming a political albatross. Can messaging change that?

Interior officials are losing their patience with states as the West’s most important river teeters on the brink of crisis.

The International Energy Agency estimates that India and other nations could buoy the fuel through 2030.

The efforts reflect a push by companies and governments to close gaps in emissions monitoring as compliance demands rise and to supplement tools like satellites to deliver a greater degree of precision or to extend coverage to more sources of pollution.

Declining rainfall and rising temperatures have dried up pasture land at the same time agricultural use has expanded.

Carmakers and suppliers say the proposals still leave them exposed to factors they can’t control. Environmental groups, on the other hand, see loopholes that’ll weaken Europe’s climate strategy, slowing the uptake of EVs that has gained momentum over the last year.

Most languages use word position and sentence structure to extract meaning. For example, “The cat sat on the box,” is not the same as “The box was on the cat.” Over a long text, like a financial document or a novel, the syntax of these words likely evolves. 

Similarly, a person might be tracking variables in a piece of code or following instructions that have conditional actions. These are examples of state changes and sequential reasoning that we expect state-of-the-art artificial intelligence systems to excel at; however, the existing, cutting-edge attention mechanism within transformers — the primarily architecture used in large language models (LLMs) for determining the importance of words — has theoretical and empirical limitations when it comes to such capabilities.

An attention mechanism allows an LLM to look back at earlier parts of a query or document and, based on its training, determine which details and words matter most; however, this mechanism alone does not understand word order. It “sees” all of the input words, a.k.a. tokens, at the same time and handles them in the order that they’re presented, so researchers have developed techniques to encode position information. This is key for domains that are highly structured, like language. But the predominant position-encoding method, called rotary position encoding (RoPE), only takes into account the relative distance between tokens in a sequence and is independent of the input data. This means that, for example, words that are four positions apart, like “cat” and “box” in the example above, will all receive the same fixed mathematical rotation specific to that relative distance. 

Now research led by MIT and the MIT-IBM Watson AI Lab has produced an encoding technique known as “PaTH Attention” that makes positional information adaptive and context-aware rather than static, as with RoPE.

“Transformers enable accurate and scalable modeling of many domains, but they have these limitations vis-a-vis state tracking, a class of phenomena that is thought to underlie important capabilities that we want in our AI systems. So, the important question is: How can we maintain the scalability and efficiency of transformers, while enabling state tracking?” says the paper’s senior author Yoon Kim, an associate professor in the Department of Electrical Engineering and Computer Science (EECS), a member of the Computer Science and Artificial Intelligence Laboratory (CSAIL), and a researcher with the MIT-IBM Watson AI Lab.

A new paper on this work was presented earlier this month at the Conference on Neural Information Processing Systems (NeurIPS). Kim’s co-authors include lead author Songlin Yang, an EECS graduate student and former MIT-IBM Watson AI Lab Summer Program intern; Kaiyue Wen of Stanford University; Liliang Ren of Microsoft; and Yikang Shen, Shawn Tan, Mayank Mishra, and Rameswar Panda of IBM Research and the MIT-IBM Watson AI Lab.

Path to understanding 

Instead of assigning every word a fixed rotation based on relative distance between tokens, as RoPE does, PaTH Attention is flexible, treating the in-between words as a path made up of small, data-dependent transformations. Each transformation, based on a mathematical operation called a Householder reflection, acts like a tiny mirror that adjusts depending on the content of each token it passes. Each step in a sequence can influence how the model interprets information later on. The cumulative effect lets the system model how the meaning changes along the path between words, not just how far apart they are. This approach allows transformers to keep track of how entities and relationships change over time, giving it a sense of “positional memory.” Think of this as walking a path while experiencing your environment and how it affects you. Further, the team also developed a hardware-efficient algorithm to more efficiently compute attention scores between every pair of tokens so that the cumulative mathematical transformation from PaTH Attention is compressed and broken down into smaller computations so that it’s compatible with fast processing on GPUs.

The MIT-IBM researchers then explored PaTH Attention’s performance on synthetic and real-world tasks, including reasoning, long-context benchmarks, and full LLM training to see whether it improved a model’s ability to track information over time. The team tested its ability to follow the most recent “write” command despite many distracting steps and multi-step recall tests, tasks that are difficult for standard positional encoding methods like RoPE. The researchers also trained mid-size LLMs and compared them against other methods. PaTH Attention improved perplexity and outcompeted other methods on reasoning benchmarks it wasn’t trained on. They also evaluated retrieval, reasoning, and stability with inputs of tens of thousands of tokens. PaTH Attention consistently proved capable of content-awareness.

“We found that both on diagnostic tasks that are designed to test the limitations of transformers and on real-world language modeling tasks, our new approach was able to outperform existing attention mechanisms, while maintaining their efficiency,” says Kim. Further, “I’d be excited to see whether these types of data-dependent position encodings, like PATH, improve the performance of transformers on structured domains like biology, in [analyzing] proteins or DNA.”

Thinking bigger and more efficiently 

The researchers then investigated how the PaTH Attention mechanism would perform if it more similarly mimicked human cognition, where we ignore old or less-relevant information when making decisions. To do this, they combined PaTH Attention with another position encoding scheme known as the Forgetting Transformer (FoX), which allows models to selectively “forget.” The resulting PaTH-FoX system adds a way to down-weight information in a data-dependent way, achieving strong results across reasoning, long-context understanding, and language modeling benchmarks. In this way, PaTH Attention extends the expressive power of transformer architectures. 

Kim says research like this is part of a broader effort to develop the “next big thing” in AI. He explains that a major driver of both the deep learning and generative AI revolutions has been the creation of “general-purpose building blocks that can be applied to wide domains,” such as “convolution layers, RNN [recurrent neural network] layers,” and, most recently, transformers. Looking ahead, Kim notes that considerations like accuracy, expressivity, flexibility, and hardware scalability have been and will be essential. As he puts it, “the core enterprise of modern architecture research is trying to come up with these new primitives that maintain or improve the expressivity, while also being scalable.”

This work was supported, in part, by the MIT-IBM Watson AI Lab and the AI2050 program at Schmidt Sciences.

Population decline often goes hand-in-hand with economic stagnation in rural areas — and the two reinforce each other in a cycle. Can digital technologies advance equitable innovation and, at the same time, preserve cultural heritage in shrinking regions?

A new open-access book, edited by MIT Vice Provost and Department of Urban Studies and Planning (DUSP) Professor Brent D. Ryan PhD ’02, Carmelo Ignaccolo PhD ’24 of Rutgers University, and Giovanna Fossa of the Politecnico di Milano, explores the transformative power of community-centered technologies in the rural areas of Italy.

“Small Town Renaissance: Bridging Technology, Heritage and Planning in Shrinking Italy” (Springer Nature, 2025) investigates the future of small towns through empirical analyses of cellphone data, bold urban design visions, collaborative digital platforms for small businesses, and territorial strategies for remote work. The work examines how technology may open up these regions to new economic opportunities. The book shares data-driven scholarly work on shrinking towns, economic development, and digital innovation from multiple planning scholars and practitioners, several of whom traveled to Italy in fall 2022 as part of a DUSP practicum taught by Ryan and Ignaccolo, and sponsored by MISTI Italy and Fondazione Rocca, in collaboration with Liminal.

“What began as a hands-on MIT practicum grew into a transatlantic book collaboration uniting scholars in design, planning, heritage, law, and telecommunications to explore how technology can sustain local economies and culture,” says Ignaccolo.

Now an assistant professor of city planning at Rutgers University’s E.J. Bloustein School of Planning and Public Policy, Ignaccolo says the book provides concrete and actionable strategies to support shrinking regions in leveraging cultural heritage and smart technologies to strengthen opportunities and local economies.

“Depopulation linked to demographic change is reshaping communities worldwide,” says Ryan. “Italy is among the hardest hit, and the United States is heading in the same direction. This project offered students a chance to harness technology and innovation to imagine bold responses to this growing challenge.”

The researchers note that similar struggles also exist in rural communities across Germany, Spain, Japan, and Korea. The book provides policymakers, urban planners, designers, tech innovators, and heritage advocates with fresh insights and actionable strategies to shape the future of rural development in the digital age. The book and chapters can be downloaded for free through most university libraries via open access.

The latest United Nations Climate Change Conference (COP30) concluded in November without a roadmap to phase out fossil fuels and without significant progress in strengthening national pledges to reduce climate-altering greenhouse gas emissions. In aggregate, today’s climate policies remain far too unambitious to meet the Paris Agreement’s goal of capping global warming at 1.5 degrees Celsius, setting the world on course to experience more frequent and intense storms, flooding, droughts, wildfires, and other climate impacts. A global policy regime aligned with the 1.5 C target would almost certainly reduce the severity of those impacts.

In the “2025 Global Change Outlook,” researchers at the MIT Center for Sustainability Science and Strategy (CS3) compare the consequences of these two approaches to climate policy through modeled projections of critical natural and societal systems under two scenarios. The Current Trends scenario represents the researchers’ assessment of current measures for reducing greenhouse gas (GHG) emissions; the Accelerated Actions scenario is a credible pathway to stabilizing the climate at a global mean surface temperature of 1.5 C above preindustrial levels, in which countries impose more aggressive GHG emissions-reduction targets.  

By quantifying the risks posed by today’s climate policies — and the extent to which accelerated climate action aligned with the 1.5 C goal could reduce them — the “Global Change Outlook” aims to clarify what’s at stake for environments and economies around the world. Here, we summarize the report’s key findings at the global level; regional details can also be accessed in several sections and through MIT CS3’s interactive global visualization tool.  

Emerging headwinds for global climate action 

Projections under Current Trends show higher GHG emissions than in our previous 2023 outlook, indicating reduced action on GHG emissions mitigation in the upcoming decade. The difference, roughly equivalent to the annual emissions from Brazil or Japan, is driven by current geopolitical events. 

Additional analysis in this report indicates that global GHG emissions in 2050 could be 10 percent higher than they would be under Current Trends if regional rivalries triggered by U.S. tariff policy prompt other regions to weaken their climate regulations. In that case, the world would see virtually no emissions reduction in the next 25 years.

Energy and electricity projections

Between 2025 and 2050, global energy consumption rises by 17 percent under Current Trends, with a nearly nine-fold increase in wind and solar. Under Accelerated Actions, global energy consumption declines by 16 percent, with a nearly 13-fold increase in wind and solar, driven by improvements in energy efficiency, wider use of electricity, and demand response. In both Current Trends and Accelerated Actions, global electricity consumption increases substantially (by 90 percent and 100 percent, respectively), with generation from low-carbon sources becoming a dominant source of power, though Accelerated Actions has a much larger share of renewables.   

“Achieving long-term climate stabilization goals will require more ambitious policy measures that reduce fossil-fuel dependence and accelerate the energy transition toward low-carbon sources in all regions of the world. Our Accelerated Actions scenario provides a pathway for scaling up global climate ambition,” says MIT CS3 Deputy Director Sergey Paltsev, co-lead author of the report.

Greenhouse gas emissions and climate projections

Under Current Trends, global anthropogenic (human-caused) GHG emissions decline by 10 percent between 2025 and 2050, but start to rise again later in the century; under Accelerated Actions, however, they fall by 60 percent by 2050. Of the two scenarios, only the latter could put the world on track to achieve long-term climate stabilization.  

Median projections for global warming by 2050, 2100, and 2150 are projected to reach 1.79, 2.74, and 3.72 degrees C (relative to the global mean surface temperature (GMST) average for the years 1850-1900) under Current Trends and 1.62, 1.56, and 1.50 C under Accelerated Actions. Median projections for global precipitation show increases from 2025 levels of 0.04, 0.11, and 0.18 millimeters per day in 2050, 2100, and 2150 under Current Trends and 0.03, 0.04, and 0.03 mm/day for those years under Accelerated Actions.

“Our projections demonstrate that aggressive cuts in GHG emissions can lead to substantial reductions in the upward trends of GMST, as well as global precipitation,” says CS3 deputy director C. Adam Schlosser, co-lead author of the outlook. “These reductions to both climate warming and acceleration of the global hydrologic cycle lower the risks of damaging impacts, particularly toward the latter half of this century.”

Implications for sustainability

The report’s modeled projections imply significantly different risk levels under the two scenarios for water availability, biodiversity, air quality, human health, economic well-being, and other sustainability indicators. 

Among the key findings: Policies that align with Accelerated Actions could yield substantial co-benefits for water availability, biodiversity, air quality, and health. For example, combining Accelerated Actions-aligned climate policies with biodiversity targets, or with air-quality targets, could achieve biodiversity and air quality/health goals more efficiently and cost-effectively than a more siloed approach. The outlook’s analysis of the global economy under Current Trends suggests that decision-makers need to account for climate impacts outside their home region and the resilience of global supply chains.  

Finally, CS3’s new data-visualization platform provides efficient, screening-level mapping of current and future climate, socioeconomic, and demographic-related conditions and changes — including global mapping for many of the model outputs featured in this report. 

“Our comparison of outcomes under Current Trends and Accelerated Actions scenarios highlights the risks of remaining on the world’s current emissions trajectory and the benefits of pursuing a much more aggressive strategy,” says CS3 Director Noelle Selin, a co-author of the report and a professor in the Institute for Data, Systems and Society and Department of Earth, Atmospheric and Planetary Sciences at MIT. “We hope that our risk-benefit analysis will help inform decision-makers in government, industry, academia, and civil society as they confront sustainability-relevant challenges.” 

This interview is part of a series of short interviews from the Department of Electrical Engineering and Computer Science (EECS). Each spotlight features a student answering their choice of questions about themselves and life at MIT. Today’s interviewee, senior Diego Temkin, is double majoring in courses 6-3 (Computer Science and Engineering) and 11 (Urban Planning). The McAllen, Texas, native is involved with MIT’s Dormitory Council (DormCon), helps to maintain Hydrant (formerly Firehose)/CourseRoad, and is both a member of the Student Information Processing Board (MIT’s oldest computing club) and an Advanced Undergraduate Research Opportunities Program (SuperUROP) scholar.

Q: What’s your favorite key on a standard computer keyboard, and why?

A: The “1” key! During Covid, I ended up starting a typewriter collection and trying to fix them up, and I always thought it was interesting how they didn’t have a 1 key. People were just expected to use the lowercase “l,” which presumably makes anyone who cares about ASCII very upset.

Q: Tell us about a teacher from your past who had an influence on the person you’ve become.

A: Back in middle school, everyone had to take a technology class that taught things like typing skills, Microsoft Word and Excel, and some other things. I was a bit of a nerd and didn’t have too many friends interested in the sort of things I was, but the teacher of that technology class, Mrs. Camarena, would let me stay for a bit after school and encouraged me to explore more of my interests. She helped me become more confident in wanting to go into computer science, and now here I am. 

Q: What’s your favorite trivia factoid?

A: Every floor in Building 13 is painted as a different MBTA line. I don’t know why and can’t really find anything about it online, but once you notice it you can’t unsee it!

Q: Do you have any pets? 

A: I do! His name is Skateboard, and he is the most quintessentially orange cat. I got him off reuse@mit.edu during my first year here at MIT (shout out to Patty K), and he’s been with me ever since. He’s currently five years old, and he’s a big fan of goldfish and stepping on my face at 7 a.m. Best decision I’ve ever made. 

Q: Are you a re-reader or a re-watcher? If so, what are your comfort books, shows, or movies?

A: Definitely a re-watcher, and definitely “Doctor Who.” I’ve watched far too much of that show and there are episodes I can recite from memory (looking at you, “The Eleventh Hour”). Anyone I know will tell you that I can go on about that show for hours, and before anyone asks, my favorite doctor is Matt Smith (sorry to the David Tennant fans; I like him too, though!)

Q: Do you have a bucket list? If so, share one or two of the items on it.

A: I’ve been wanting to take a cross-country Amtrak trip for a while … I think I might try going to the West Coast and some national parks during IAP [Independent Activities Period], if I have the time. Now that it’s on here, I definitely have to do it!

Why did humans evolve the eyes we have today?

While scientists can’t go back in time to study the environmental pressures that shaped the evolution of the diverse vision systems that exist in nature, a new computational framework developed by MIT researchers allows them to explore this evolution in artificial intelligence agents.

The framework they developed, in which embodied AI agents evolve eyes and learn to see over many generations, is like a “scientific sandbox” that allows researchers to recreate different evolutionary trees. The user does this by changing the structure of the world and the tasks AI agents complete, such as finding food or telling objects apart.

This allows them to study why one animal may have evolved simple, light-sensitive patches as eyes, while another has complex, camera-type eyes.

The researchers’ experiments with this framework showcase how tasks drove eye evolution in the agents. For instance, they found that navigation tasks often led to the evolution of compound eyes with many individual units, like the eyes of insects and crustaceans.

On the other hand, if agents focused on object discrimination, they were more likely to evolve camera-type eyes with irises and retinas.

This framework could enable scientists to probe “what-if” questions about vision systems that are difficult to study experimentally. It could also guide the design of novel sensors and cameras for robots, drones, and wearable devices that balance performance with real-world constraints like energy efficiency and manufacturability.

“While we can never go back and figure out every detail of how evolution took place, in this work we’ve created an environment where we can, in a sense, recreate evolution and probe the environment in all these different ways. This method of doing science opens to the door to a lot of possibilities,” says Kushagra Tiwary, a graduate student at the MIT Media Lab and co-lead author of a paper on this research.

He is joined on the paper by co-lead author and fellow graduate student Aaron Young; graduate student Tzofi Klinghoffer; former postdoc Akshat Dave, who is now an assistant professor at Stony Brook University; Tomaso Poggio, the Eugene McDermott Professor in the Department of Brain and Cognitive Sciences, an investigator in the McGovern Institute, and co-director of the Center for Brains, Minds, and Machines; co-senior authors Brian Cheung, a postdoc in the  Center for Brains, Minds, and Machines and an incoming assistant professor at the University of California San Francisco; and Ramesh Raskar, associate professor of media arts and sciences and leader of the Camera Culture Group at MIT; as well as others at Rice University and Lund University. The research appears today in Science Advances.

Building a scientific sandbox

The paper began as a conversation among the researchers about discovering new vision systems that could be useful in different fields, like robotics. To test their “what-if” questions, the researchers decided to use AI to explore the many evolutionary possibilities.

“What-if questions inspired me when I was growing up to study science. With AI, we have a unique opportunity to create these embodied agents that allow us to ask the kinds of questions that would usually be impossible to answer,” Tiwary says.

To build this evolutionary sandbox, the researchers took all the elements of a camera, like the sensors, lenses, apertures, and processors, and converted them into parameters that an embodied AI agent could learn.

They used those building blocks as the starting point for an algorithmic learning mechanism an agent would use as it evolved eyes over time.

“We couldn’t simulate the entire universe atom-by-atom. It was challenging to determine which ingredients we needed, which ingredients we didn’t need, and how to allocate resources over those different elements,” Cheung says.

In their framework, this evolutionary algorithm can choose which elements to evolve based on the constraints of the environment and the task of the agent.

Each environment has a single task, such as navigation, food identification, or prey tracking, designed to mimic real visual tasks animals must overcome to survive. The agents start with a single photoreceptor that looks out at the world and an associated neural network model that processes visual information.

Then, over each agent’s lifetime, it is trained using reinforcement learning, a trial-and-error technique where the agent is rewarded for accomplishing the goal of its task. The environment also incorporates constraints, like a certain number of pixels for an agent’s visual sensors.

“These constraints drive the design process, the same way we have physical constraints in our world, like the physics of light, that have driven the design of our own eyes,” Tiwary says.

Over many generations, agents evolve different elements of vision systems that maximize rewards.

Their framework uses a genetic encoding mechanism to computationally mimic evolution, where individual genes mutate to control an agent’s development.

For instance, morphological genes capture how the agent views the environment and control eye placement; optical genes determine how the eye interacts with light and dictate the number of photoreceptors; and neural genes control the learning capacity of the agents.

Testing hypotheses

When the researchers set up experiments in this framework, they found that tasks had a major influence on the vision systems the agents evolved.

For instance, agents that were focused on navigation tasks developed eyes designed to maximize spatial awareness through low-resolution sensing, while agents tasked with detecting objects developed eyes focused more on frontal acuity, rather than peripheral vision.

Another experiment indicated that a bigger brain isn’t always better when it comes to processing visual information. Only so much visual information can go into the system at a time, based on physical constraints like the number of photoreceptors in the eyes.

“At some point a bigger brain doesn’t help the agents at all, and in nature that would be a waste of resources,” Cheung says.

In the future, the researchers want to use this simulator to explore the best vision systems for specific applications, which could help scientists develop task-specific sensors and cameras. They also want to integrate LLMs into their framework to make it easier for users to ask “what-if” questions and study additional possibilities.

“There’s a real benefit that comes from asking questions in a more imaginative way. I hope this inspires others to create larger frameworks, where instead of focusing on narrow questions that cover a specific area, they are looking to answer questions with a much wider scope,” Cheung says.

This work was supported, in part, by the Center for Brains, Minds, and Machines and the Defense Advanced Research Projects Agency (DARPA) Mathematics for the Discovery of Algorithms and Architectures (DIAL) program.

When Freesia Gaul discovered MIT Open Learning’s OpenCourseWare at just 14 years old, it opened up a world of learning far beyond what her classrooms could offer. Her parents had started a skiing company, and the seasonal work meant that Gaul had to change schools every six months. Growing up in small towns in Australia and Canada, she relied on the internet to fuel her curiosity.

“I went to 13 different schools, which was hard because you're in a different educational system every single time,” says Gaul. “That’s one of the reasons I gravitated toward online learning and teaching myself. Knowledge is something that exists beyond a curriculum.”

The small towns she lived in often didn’t have a lot of resources, she says, so a computer served as a main tool for learning. She enjoyed engaging with Wikipedia, ultimately researching topics and writing and editing content for pages. In 2018, she discovered MIT OpenCourseWare, part of MIT Open Learning, and took her first course. OpenCouseWare offers free, online, open educational resources from more than 2,500 MIT undergraduate and graduate courses. 

“I really got started with the OpenCourseWare introductory electrical engineering classes, because I couldn’t find anything else quite like it online,” says Gaul, who was initially drawn to courses on circuits and electronics, such as 6.002 (Circuits and Electronics) and 6.01SC (Introduction to Electrical Engineering and Computer Science). “It really helped me in terms of understanding how electrical engineering worked in a practical sense, and I just started modding things.”

In true MIT “mens et manus” (“mind and hand”) fashion, Gaul spent much of her childhood building and inventing, especially when she was able to access a 3D printer. She says that a highlight was when she built a life-sized, working version of a Mario Kart, constructed out of materials she had printed.

Gaul calls herself a “serial learner,” and has taken many OpenCourseWare courses. In addition to classes on circuits and electronics, she also took courses in linear algebra, calculus, and quantum physics — in which she took a particular interest. 

When she was 15, she participated in Qubit by Qubit. Hosted by The Coding School, in collaboration with universities (including MIT) and tech companies, this two-semester course introduces high schoolers to quantum computing and quantum physics. 

During that time she started a blog called On Zero, representing the “zero state” of a qubit. “The ‘zero state’ in a quantum computer is the representation of creativity from nothing, infinite possibilities,” says Gaul. For the blog, she found different topics and researched them in depth. She would think of a topic or question, such as “What is color?” and then explore it in great detail. What she learned eventually led her to start asking questions such as “What is a hamiltonian?” and teaching quantum physics alongside PhDs.

Building on these interests, Gaul chose to study quantum engineering at the University of New South Wales. She notes that on her first day of university, she participated in iQuHack, the MIT Quantum Hackathon. Her team worked to find a new way to approximate the value of a hyperbolic function using quantum logic, and received an honorable mention for “exceptional creativity.”

Gaul’s passion for making things continued during her college days, especially in terms of innovating to solve a problem. When she found herself on a train, wanting to code a personal website on a computer with a dying battery, she wondered if there might be a way to make a glove that can act as a type of Bluetooth keyboard — essentially creating a way to type in the air. In her spare time, she started working on such a device, ultimately finding a less expensive way to build a lightweight, haptic, gesture-tracking glove with applications for virtual reality (VR) and robotics.

Gaul says she has always had an interest in VR, using it to create her own worlds, reconstruct an old childhood house, and play Dungeons and Dragons with friends. She discovered a way to put into a glove some small linear resonant actuators, which can be found in a smartphone or gaming controller, and map to any object in VR so that the user can feel it.

An early prototype that Gaul put together in her dorm room received a lot of attention on YouTube. She went on to win the People’s Choice award for it at the SxSW Sydney 2025 Tech and Innovation Festival. This design also sparked her co-founding of the tech startup On Zero, named after her childhood blog dedicated to the love of creation from nothing.

Gaul sees the device, in general, as a way of “paying it forward,” making improved human-computer interaction available to many — from young students to professional technologists. She hopes to enable creative freedom in as many as she can. “The mind is just such a fun thing. I want to empower others to have the freedom to follow their curiosity, even if it's pointless on paper.

“I’ve benefited from people going far beyond what they needed to do to help me,” says Gaul. “I see OpenCourseWare as a part of that. The free courses gave me a solid foundation of knowledge and problem-solving abilities. Without these, it wouldn’t be possible to do what I’m doing now.”

Another year has come and gone, and with it, thousands of data breaches that affect millions of people. The question these days is less, Is my information in a data breach this year? and more How many data breaches had my information in them this year? 

Some data breaches are more noteworthy than others. Where one might affect a small number of people and include little useful information, like a name or email address, others might include data ranging from a potential medical diagnosis to specific location information. To catalog and talk about these breaches we created the Breachies, a series of tongue-in-cheek awards, to highlight the most egregious data breaches. 

In most cases, if these companies practiced a privacy first approach and focused on data minimization, only collecting and storing what they absolutely need to provide the services they promise, many data breaches would be far less harmful to the victims. But instead, companies gobble up as much as they can, store it for as long as possible, and inevitably at some point someone decides to poke in and steal that data. Once all that personal data is stolen, it can be used against the breach victims for identity theft, ransomware attacks, and to send unwanted spam. It has become such a common occurrence that it’s easy to lose track of which breaches affect you, and just assume your information is out there somewhere. Still, a few steps can help protect your information.

With that, let’s get to the awards.

The Winners

• The Say Something Without Saying Anything Award: Mixpanel
• The We Still Told You So Award: Discord
• The Tea for Two Award: Tea Dating Advice and TeaOnHer
• The Just Stop Using Tracking Tech Award: Blue Shield of California
• The Hacker's Hall Pass Award: PowerSchool
• The Worst. Customer. Service. Ever. Award: TransUnion
• The Annual Microsoft Screwed Up Again Award: Microsoft
• The I Didn’t Even Know You Had My Information Award: Gravy Analytics
• The Keeping Up With My Cybertruck Award: Teslamate
• The Disorder in the Courts Award: PACER
• The Only Stalkers Allowed Award: Catwatchful
• The Why We’re Still Stuck on Unique Passwords Award: Plex
• The Uh, Yes, Actually, I Have Been Pwned Award: Troy Hunt’s Mailing List
• (Dis)honorable Mentions

The Say Something Without Saying Anything Award: Mixpanel

We’ve long warned that apps delivering your personal information to third-parties, even if they aren’t the ad networks directly driving surveillance capitalism, presents risks and a salient target for hackers. The more widespread your data, the more places attackers can go to find it. Mixpanel, a data analytics company which collects information on users of any app which incorporates its SDK, suffered a major breach in November this year. The service has been used by a wide array of companies, including the Ring Doorbell App, which we reported on back in 2020 delivering a trove of information to Mixpanel, and PornHub, which despite not having worked with the company since 2021, had its historical record of paying subscribers breached.    

There’s a lot we still don’t know about this data breach, in large part because the announcement about it is so opaque, leaving reporters with unanswered questions about how many were affected, if the hackers demanded a ransom, and if Mixpanel employee accounts utilized standard security best practices. One thing is clear, though: the breach was enough for OpenAI to drop them as a provider, disclosing critical details on the breach in a blog post that Mixpanel’s own announcement conveniently failed to mention.

The worst part is that, as a data analytics company providing libraries which are included in a broad range of apps, we can surmise that the vast majority of people affected by this breach have no direct relationship with Mixpanel, and likely didn’t even know that their devices were delivering data to the company. These people deserve better than vague statements by companies which profit off of (and apparently insufficiently secure) their data.

The We Still Told You So Award: Discord

Last year, AU10TIX won our first The We Told You So Award because as we predicted in 2023, age verification mandates would inevitably lead to more data breaches, potentially exposing government IDs as well as information about the sites that a user visits. Like clockwork, they did. It was our first We Told You So Breachies award, but we knew it wouldn’t be the last. 

Unfortunately, there is growing political interest in mandating identity or age verification before allowing people to access social media or adult material. EFF and others oppose these plans because they threaten both speech and privacy. 

Nonetheless, this year’s winner of The We Still Told You So Breachies Award is the messaging app, Discord — once known mainly for gaming communities, it now hosts more than 200 million monthly active users and is widely used to host fandom and community channels. 

In September of this year, much of Discord’s age verification data was breached — including users’ real names, selfies, ID documents, email and physical addresses, phone numbers, IP addresses, and other contact details or messages provided to customer support. In some cases, “limited billing information” was also accessed—including payment type, the last four digits of credit card numbers, and purchase histories. 

Technically though, it wasn’t Discord itself that was hacked but their third-party customer support provider — a company called Zendesk—that was compromised, allowing attackers to access Discord’s user data. Either way, it’s Discord users who felt the impact. 

The Tea for Two Award: Tea Dating Advice and TeaOnHer

Speaking of age verification, Tea, the dating safety app for women, had a pretty horrible year for data breaches. The app allows users to anonymously share reviews and safety information about their dates with men—helping keep others safe by noting red flags they saw during their date.

Since Tea is aimed at women’s safety and dating advice, the app asks new users to upload a selfie or photo ID to verify their identity and gender to create an account. That’s some pretty sensitive information that the app is asking you to trust it with! Back in July, it was reported that 72,000 images had been leaked from the app, including 13,000 images of photo IDs and 59,000 selfies. These photos were found via an exposed database hosted on Google’s mobile app development platform, Firebase. And if that isn’t bad enough, just a week later a second breach exposed private messages between users, including messages with phone numbers, abortion planning, and discussions about cheating partners. This breach included more than 1.1 million messages from early 2023 all the way to mid-2025, just before the breach was reported. Tea released a statement shortly after, temporarily disabling the chat feature.

But wait, there’s more. A completely different app based on the same idea, but for men, also suffered a data breach. TeaOnHer failed to protect similar sensitive data. In August, TechCrunch discovered that user information — including emails, usernames, and yes, those photo IDs and selfies — was accessible through a publicly available web address. Even worse? TechCrunch also found the email address and password the app’s creator uses to access the admin page.

Breaches like this are one of the reasons that EFF shouts from the rooftops against laws that mandate user verification with an ID or selfie. Every company that collects this information becomes a target for data breaches — and if a breach happens, you can’t just change your face. 

The Just Stop Using Tracking Tech Award: Blue Shield of California

Another year, another data breach caused by online tracking tools. 

In April, Blue Shield of California revealed that it had shared 4.7 million people’s health data with Google by misconfiguring Google Analytics on its website. The data, which may have been used for targeted advertising, included: people’s names, insurance plan details, medical service providers, and patient financial responsibility. The health insurance company shared this information with Google for nearly three years before realizing its mistake.

If this data breach sounds familiar, it’s because it is: last year’s Just Stop Using Tracking Tech award also went to a healthcare company that leaked patient data through tracking code on its website. Tracking tools remain alarmingly common on healthcare websites, even after years of incidents like this one. These tools are marketed as harmless analytics or marketing solutions, but can expose people’s sensitive data to advertisers and data brokers. 

EFF’s free Privacy Badger extension can block online trackers, but you shouldn’t need an extension to stop companies from harvesting and monetizing your medical data. We need a strong, federal privacy law and ban on online behavioral advertising to eliminate the incentives driving companies to keep surveilling us online. 

The Hacker's Hall Pass Award: PowerSchool

 In December 2024, PowerSchool, the largest provider of student information systems in the U.S., gave hackers access to sensitive student data. The breach compromised personal information of over 60 million students and teachers, including Social Security numbers, medical records, grades, and special education data. Hackers exploited PowerSchool’s weak security—namely, stolen credentials to their internal customer support portal—and gained unfettered access to sensitive data stored by school districts across the country.

PowerSchool failed to implement basic security measures like multi-factor authentication, and the breach affected districts nationwide. In Texas alone, over 880,000 individuals’ data was exposed, prompting the state's attorney general to file a lawsuit, accusing PowerSchool of misleading its customers about security practices. Memphis-Shelby County Schools also filed suit, seeking damages for the breach and the cost of recovery.

While PowerSchool paid hackers an undisclosed sum to prevent data from being published, the company’s failure to protect its users’ data raises serious concerns about the security of K-12 educational systems. Adding to the saga, a Massachusetts student, Matthew Lane, pleaded guilty in October to hacking and extorting PowerSchool for $2.85 million in Bitcoin. Lane faces up to 17 years in prison for cyber extortion and aggravated identity theft, a reminder that not all hackers are faceless shadowy figures — sometimes they’re just a college kid.

The Worst. Customer. Service. Ever. Award: TransUnion

Credit reporting giant TransUnion had to notify its customers this year that a hack nabbed the personal information of 4.4 million people. How'd the attackers get in? According to a letter filed with the Maine Attorney General's office obtained by TechCrunch, the problem was a “third-party application serving our U.S. consumer support operations.” That's probably not the kind of support they were looking for. 

TransUnion said in a Texas filing that attackers swept up “customers’ names, dates of birth, and Social Security numbers” in the breach, though it was quick to point out in public statements that the hackers did not access credit reports or “core credit data.” While it certainly could have been worse, this breach highlights the many ways that hackers can get their hands on information. Coming in through third-parties, companies that provide software or other services to businesses, is like using an unguarded side door, rather than checking in at the front desk. Companies, particularly those who keep sensitive personal information, should be sure to lock down customer information at all the entry points. After all, their decisions about who they do business with ultimately carry consequences for all of their customers — who have no say in the matter.

The Annual Microsoft Screwed Up Again Award: Microsoft

Microsoft is a company nobody feels neutral about. Especially in the infosec world. The myriad software vulnerabilities in Windows, Office, and other Microsoft products over the decades has been a source of frustration and also great financial rewards for both attackers and defenders. Yet still, as the saying goes: “nobody ever got fired for buying from Microsoft.” But perhaps, the times, they are a-changing. 

In July 2025, it was revealed that a zero-day security vulnerability in Microsoft’s flagship file sharing and collaboration software, SharePoint, had led to the compromise of over 400 organizations, including major corporations and sensitive government agencies such as the National Nuclear Security Administration (NNSA), the federal agency responsible for maintaining and developing the U.S. stockpile of nuclear weapons. The attack was attributed to three different Chinese government linked hacking groups. Amazingly, days after the vulnerability was first reported, there were still thousands of vulnerable self-hosted Sharepoint servers online. 

Zero-days happen to tech companies, large and small. It’s nearly impossible to write even moderately complex software that is bug and exploit free, and Microsoft can’t exactly be blamed for having a zero-day in their code. But when one company is the source of so many zero-days consistently for so many years, one must start wondering whether they should put all their eggs (or data) into a basket that company made. Perhaps if Microsoft’s monopolistic practices had been reined in back in the 1990s we wouldn’t be in a position today where Sharepoint is the defacto file sharing software for so many major organizations. And maybe, just maybe, this is further evidence that tech monopolies and centralization of data aren’t just bad for consumer rights, civil liberties, and the economy—but also for cybersecurity. 

The Silver Globe Award: Flat Earth Sun, Moon & Zodiac

Look, we’ll keep this one short: in October of last year, researchers found security issues in the flat earther app, Flat Earth, Sun, Moon, & Clock. In March of 2025, that breach was confirmed. What’s most notable about this, aside from including a surprising amount of information about gender, name, email addresses and date of birth, is that it also included users’ location info, including latitude and longitude. Huh, interesting.

The I Didn’t Even Know You Had My Information Award: Gravy Analytics

In January, hackers claimed they stole millions of people’s location history from a company that never should’ve had it in the first place: location data broker Gravy Analytics. The data included timestamped location coordinates tied to advertising IDs, which can reveal exceptionally sensitive information. In fact, researchers who reviewed the leaked data found it could be used to identify military personnel and gay people in countries where homosexuality is illegal. 

The breach of this sensitive data is bad, but Gravy Analytics’s business model of regularly harvesting and selling it is even worse. Despite the fact that most people have never heard of them, Gravy Analytics has managed to collect location information from a billion phones a day. The company has sold this data to other data brokers, makers of police surveillance tools, and the U.S. government. 

How did Gravy Analytics get this location information from people’s phones? The data broker industry is notoriously opaque, but this breach may have revealed some of Gravy Analytics’ sources. The leaked data referenced thousands of apps, including Microsoft apps, Candy Crush, Tinder, Grindr, MyFitnessPal, pregnancy trackers and religious-focused apps. Many of these app developers said they had no relationship with Gravy Analytics. Instead, expert analysis of the data suggests it was harvested through the advertising ecosystem already connected to most apps. This breach provides further evidence that online behavioral advertising fuels the surveillance industry. 

Whether or not they get hacked, location data brokers like Gravy Analytics threaten our privacy and security. Follow EFF’s guide to protecting your location data and help us fight for legislation to dismantle the data broker industry. 

The Keeping Up With My Cybertruck Award: Teslamate

TeslaMate, a tool meant to track Tesla vehicle data (but which is not owned or operated by Tesla itself), has become a cautionary tale about data security. In August, a security researcher found more than 1,300 self-hosted TeslaMate dashboards were exposed online, leaking sensitive information such as vehicle location, speed, charging habits, and even trip details. In essence, your Cybertruck became the star of its own Keeping Up With My Cybertruck reality show, except the audience wasn’t made up of fans interested in your lifestyle, just random people with access to the internet.

TeslaMate describes itself as “that loyal friend who never forgets anything!” — but its lack of proper security measures makes you wish it would. This breach highlights how easily location data can become a tool for harassment or worse, and the growing need for legislation that specifically protects consumer location data. Without stronger regulations around data privacy, sensitive location details like where you live, work, and travel can easily be accessed by malicious actors, leaving consumers with no recourse.

The Disorder in the Courts Award: PACER

Confidentiality is a core principle in the practice of law. But this year a breach of confidentiality came from an unexpected source: a breach of the federal court filing system. In August, Politico reported that hackers infiltrated the Case Management/Electronic Case Files (CM/ECF) system, which uses the same database as PACER, a searchable public database for court records. Of particular concern? The possibility that the attack exposed the names of confidential informants involved in federal cases from multiple court districts. Courts across the country acted quickly to set up new processes to avoid the possibility of further compromises.

The leak followed a similar incident in 2021 and came on the heels of a warning to Congress that the file system is more than a little creaky. In fact, an IT official from the federal court system told the House Judiciary Committee that both systems are “unsustainable due to cyber risks, and require replacement.”

The Only Stalkers Allowed Award: Catwatchful

Just like last year, a stalkerware company was subject to a data breach that really should prove once and for all that these companies must be stopped. In this case, Catwatchful is an Android spyware company that sells itself as a “child monitoring app.” Like other products in this category, it’s designed to operate covertly while uploading the contents of a victim’s phone, including photos, messages, and location information.

This data breach was particularly harmful, as it included not just the email addresses and passwords on the customers who purchased the app to install on a victim’s phone, but also the data from the phones of 26,000 victims’ devices, which could include the victims’ photos, messages, and real-time location data.

This was a tough award to decide on because Catwatchful wasn’t the only stalkerware company that was hit this year. Similar breaches to SpyX, Cocospy, and Spyic were all strong contenders. EFF has worked tirelessly to raise the alarm on this sort of software, and this year worked with AV Comparatives to test the stalkerware detection rate on Android of various major antivirus apps.

The Why We’re Still Stuck on Unique Passwords Award: Plex

Every year, we all get a reminder about why using unique passwords for all our accounts is crucial for protecting our online identities. This time around, the award goes to Plex, who experienced a data breach that included customer emails, usernames, and hashed passwords (which is a fancy way of saying passwords are scrambled through an algorithm, but it is possible they could still be deciphered).

If this all sounds vaguely familiar to you for some reason, that’s because a similar issue also happened to Plex in 2022, affecting 15 million users. Whoops.

This is why it is important to use unique passwords everywhere. A password manager, including one that might be free on your phone or browser, makes this much easier to do. Likewise, credential stuffing illustrates why it’s important to use two-factor authentication. Here’s how to turn that on for your Plex account.

The Uh, Yes, Actually, I Have Been Pwned Award: Troy Hunt’s Mailing List

Troy Hunt, the person behind Have I Been Pwned? and who has more experience with data breaches than just about anyone, also proved that anyone can be pwned. In a blog post, he details what happened to his mailing list:

You know when you're really jet lagged and really tired and the cogs in your head are just moving that little bit too slow? That's me right now, and the penny has just dropped that a Mailchimp phish has grabbed my credentials, logged into my account and exported the mailing list for this blog.

And he continues later:

I'm enormously frustrated with myself for having fallen for this, and I apologise to anyone on that list. Obviously, watch out for spam or further phishes and check back here or via the social channels in the nav bar above for more.

The whole blog is worth a read as a reminder that phishing can get anyone, and we thank Troy Hunt for his feedback on this and other breaches to include this year.

Tips to Protect Yourself

Data breaches are such a common occurrence that it’s easy to feel like there’s nothing you can do, nor any point in trying. But privacy isn’t dead. While some information about you is almost certainly out there, that’s no reason for despair. In fact, it’s a good reason to take action.

There are steps you can take right now with all your online accounts to best protect yourself from the the next data breach (and the next, and the next):

• Use unique passwords on all your online accounts. This is made much easier by using a password manager, which can generate and store those passwords for you. When you have a unique password for every website, a data breach of one site won’t cascade to others.
• Use two-factor authentication when a service offers it. Two-factor authentication makes your online accounts more secure by requiring additional proof (“factors”) alongside your password when you log in. While two-factor authentication adds another step to the login process, it’s a great way to help keep out anyone not authorized, even if your password is breached.
• Delete old accounts: Sometimes, you’ll get a data breach notification for an account you haven’t used in years. This can be a nice reminder to delete that account, but it’s better to do so before a data breach happens, when possible. Try to make it a habit to go through and delete old accounts once a year or so. 
• Freeze your credit. Many experts recommend freezing your credit with the major credit bureaus as a way to protect against the sort of identity theft that’s made possible by some data breaches. Freezing your credit prevents someone from opening up a new line of credit in your name without additional information, like a PIN or password, to “unfreeze” the account. This might sound absurd considering they can’t even open bank accounts, but if you have kids, you can freeze their credit too.
• Keep a close eye out for strange medical bills. With the number of health companies breached this year, it’s also a good idea to watch for healthcare fraud. The Federal Trade Commission recommends watching for strange bills, letters from your health insurance company for services you didn’t receive, and letters from debt collectors claiming you owe money. 

(Dis)Honorable Mentions

According to one report, 2025 had already seen 2,563 data breaches by October, which puts the year on track to be one of the worst by the sheer number of breaches.

We did not investigate every one of these 2,500-plus data breaches, but we looked at a lot of them, including the news coverage and the data breach notification letters that many state Attorney General offices host on their websites. We can’t award the coveted Breachies Award to every company that was breached this year. Still, here are some (dis)honorable mentions we wanted to highlight:

Salesforce, F5, Oracle, WorkComposer, Raw, Stiizy, Ohio Medical Alliance LLC, Hello Cake, Lovense, Kettering Health, LexisNexis, WhatsApp, Nexar, McDonalds, Congressional Budget Office, Doordash, Louis Vuitton, Adidas, Columbia University, Hertz, HCRG Care Group, Lexipol, Color Dating, Workday, Aflac, and Coinbase. And a special nod to last minute entrants Home Depot, 700Credit, and Petco.

What now? Companies need to do a better job of only collecting the information they need to operate, and properly securing what they store. Also, the U.S. needs to pass comprehensive privacy protections. At the very least, we need to be able to sue companies when these sorts of breaches happen (and while we’re at it, it’d be nice if we got more than $5.21 checks in the mail). EFF has long advocated for a strong federal privacy law that includes a private right of action.

Facing hospital closures, underfunded pediatric trials, and a persistent reliance on adult-oriented tools for children, the Hood Pediatric Innovation Hub welcomed nearly 200 leaders at Boston’s Museum of Science for MIT-Hood Pediatric Innovation 2025, an event focused on transforming the future of pediatric care through engineering and collaboration.

Hosted by the Hood Pediatric Innovation Hub — established at MIT through a gift by the Hood Foundation — the event brought together attendees from academia, health care, and industry to rethink how medical and technological breakthroughs can reach children faster. The gathering marked a new phase in the hub’s mission to connect scientific discovery with real-world impact.

“We have extraordinary science emerging every day, but the translation gap is widening,” said Joseph Frassica, professor of the practice in MIT’s Institute for Medical Engineering and Science and executive director of the Hood Pediatric Innovation Hub. “We can’t rely on the old model of innovation — we need new connective tissue between ideas, institutions, and implementation.”

Building collaboration across sectors

Speakers emphasized that pediatric medicine has long faced structural disadvantages compared with other fields — from smaller patient populations to limited commercial incentives. Yet they also described a powerful opportunity: to make pediatric innovation a proving ground for smarter, more human-centered health systems.

“The Hood Foundation has always believed that if you can improve care for children, you improve care for everyone,” said Neil Smiley, president of the Charles H. Hood Foundation. “Pediatrics pushes medicine to be smarter, more precise, and more humane — and that’s why this collaboration with MIT feels so right.”

Participants discussed how aligning efforts across universities, hospitals, and industry partners could help overcome the fragmentation that slows innovation, and ultimately translation. Speakers at the event highlighted case studies where cross-sector collaboration is already yielding results — from novel medical devices to data-driven clinical insights.

Connecting discovery to delivery

In his remarks, Elazer R. Edelman, the Edward J. Poitras Professor in Medical Engineering and Science at MIT and faculty lead for the Hood Pediatric Innovation Hub, reflected on how MIT’s engineering and medical communities can help close the loop between research and clinical application.

“This isn’t about creating something new for the sake of it — it’s about finally connecting the extraordinary expertise that already exists, from the lab to the clinic to the child’s bedside,” Edelman said. “That’s what MIT does best — we connect the dots.”

Throughout the day, attendees shared experiences from both the engineering and clinical viewpoints — acknowledging the complexities of regulation, funding, and adoption, while highlighting the shared responsibility to move faster on behalf of children.

A moment of convergence

The conversation also turned to the economics of innovation and the broader societal benefits of investing in pediatric health.

“The economic and social stakes couldn’t be higher,” said Jonathan Gruber, Ford Professor of Economics at MIT. “When we invest in children’s health, we invest in longer lives, stronger communities, and greater prosperity. The energy in this room shows what’s possible when we stop working in silos.”

By the end of the event, discussions had shifted from identifying barriers to designing solutions. Participants explored ideas ranging from translational fellowships and shared data platforms to new models for academic–industry partnership — each aimed at accelerating impact where it is needed most.

Looking ahead

“There’s a feeling that this is the moment,” Frassica said. “We have the tools, the data, and the will to transform how we care for children. The key now is keeping that spirit of collaboration alive — because when we do, we move the whole field forward.”

Building on the momentum from MIT-Hood Pediatric Innovation 2025, the Hood Pediatric Innovation Hub will continue to serve as a connector across disciplines and institutions, advancing projects that translate cutting-edge research into improved outcomes for children everywhere. In January, a new cohort of MIT Catalyst Fellows — early-career researchers embedded with frontline clinicians to identify unmet needs — will begin exploring solutions to challenges in pediatric and neonatal health care in partnership with the hub. 

This work is also part of a wider Institute effort. The Hood Pediatric Innovation Hub contributes to the broader mission of the MIT Health and Life Sciences Collaborative (HEALS), which brings together faculty, clinicians, and industry partners to accelerate breakthroughs across all areas of human health. As the hub deepens its own collaborations, its connection to HEALS helps ensure that advances in pediatric medicine are integrated into MIT’s larger push to improve health outcomes at scale.

The hub will also release a request for proposals in the coming months for the development of its first mentored projects — designed to bring together teams from engineering, medicine, and industry to accelerate progress in children’s health. Updates and details will be available at hoodhub.mit.edu.

As Smiley noted, progress in pediatric health often drives progress across all of medicine — and this gathering underscored that shared belief: when we work together for children, we build a healthier future for everyone.

As people age, their immune system function declines. T cell populations become smaller and can’t react to pathogens as quickly, making people more susceptible to a variety of infections.

To try to overcome that decline, researchers at MIT and the Broad Institute have found a way to temporarily program cells in the liver to improve T-cell function. This reprogramming can compensate for the age-related decline of the thymus, where T cell maturation normally occurs.

Using mRNA to deliver three key factors that usually promote T-cell survival, the researchers were able to rejuvenate the immune systems of mice. Aged mice that received the treatment showed much larger and more diverse T cell populations in response to vaccination, and they also responded better to cancer immunotherapy treatments.

If developed for use in patients, this type of treatment could help people lead healthier lives as they age, the researchers say.

“If we can restore something essential like the immune system, hopefully we can help people stay free of disease for a longer span of their life,” says Feng Zhang, the James and Patricia Poitras Professor of Neuroscience at MIT, who has joint appointments in the departments of Brain and Cognitive Sciences and Biological Engineering.

Zhang, who is also an investigator at the McGovern Institute for Brain Research at MIT, a core institute member at the Broad Institute of MIT and Harvard, an investigator in the Howard Hughes Medical Institute, and co-director of the K. Lisa Yang and Hock E. Tan Center for Molecular Therapeutics at MIT, is the senior author of the new study. Former MIT postdoc Mirco Friedrich is the lead author of the paper, which appears today in Nature.

A temporary factory

The thymus, a small organ located in front of the heart, plays a critical role in T-cell development. Within the thymus, immature T cells go through a checkpoint process that ensures a diverse repertoire of T cells. The thymus also secretes cytokines and growth factors that help T cells to survive.

However, starting in early adulthood, the thymus begins to shrink. This process, known as thymic involution, leads to a decline in the production of new T cells. By the age of approximately 75, the thymus is greatly reduced.

“As we get older, the immune system begins to decline. We wanted to think about how can we maintain this kind of immune protection for a longer period of time, and that's what led us to think about what we can do to boost immunity,” Friedrich says.

Previous work on rejuvenating the immune system has focused on delivering T cell growth factors into the bloodstream, but that can have harmful side effects. Researchers are also exploring the possibility of using transplanted stem cells to help regrow functional tissue in the thymus.

The MIT team took a different approach: They wanted to see if they could create a temporary “factory” in the body that would generate the T-cell-stimulating signals that are normally produced by the thymus.

“Our approach is more of a synthetic approach,” Zhang says. “We're engineering the body to mimic thymic factor secretion.”

For their factory location, they settled on the liver, for several reasons. First, the liver has a high capacity for producing proteins, even in old age. Also, it’s easier to deliver mRNA to the liver than to most other organs of the body. The liver was also an appealing target because all of the body’s circulating blood has to flow through it, including T cells.

To create their factory, the researchers identified three immune cues that are important for T-cell maturation. They encoded these three factors into mRNA sequences that could be delivered by lipid nanoparticles. When injected into the bloodstream, these particles accumulate in the liver and the mRNA is taken up by hepatocytes, which begin to manufacture the proteins encoded by the mRNA.

The factors that the researchers delivered are DLL1, FLT-3, and IL-7, which help immature progenitor T cells mature into fully differentiated T cells.

Immune rejuvenation

Tests in mice revealed a variety of beneficial effects. First, the researchers injected the mRNA particles into 18-month-old mice, equivalent to humans in their 50s. Because mRNA is short-lived, the researchers gave the mice multiple injections over four weeks to maintain a steady production by the liver.

After this treatment, T cell populations showed significant increases in size and function.

The researchers then tested whether the treatment could enhance the animals’ response to vaccination. They vaccinated the mice with ovalbumin, a protein found in egg whites that is commonly used to study how the immune system responds to a specific antigen. In 18-month-old mice that received the mRNA treatment before vaccination, the researchers found that the population of cytotoxic T-cells specific to ovalbumin doubled, compared to mice of the same age that did not receive the mRNA treatment.

The mRNA treatment can also boost the immune system’s response to cancer immunotherapy, the researchers found. They delivered the mRNA treatment to 18-month-old mice, who were then implanted with tumors and treated with a checkpoint inhibitor drug. This drug, which targets the protein PD-L1, is designed to help take the brakes off the immune system and stimulate T cells to attack tumor cells.

Mice that received the treatment showed much higher survival rates and longer lifespan that those that received the checkpoint inhibitor drug but not the mRNA treatment.

The researchers found that all three factors were necessary to induce this immune enhancement; none could achieve all aspects of it on their own. They now plan to study the treatment in other animal models and to identify additional signaling factors that may further enhance immune system function. They also hope to study how the treatment affects other immune cells, including B cells.

Other authors of the paper include Julie Pham, Jiakun Tian, Hongyu Chen, Jiahao Huang, Niklas Kehl, Sophia Liu, Blake Lash, Fei Chen, Xiao Wang, and Rhiannon Macrae.

The research was funded, in part, by the Howard Hughes Medical Institute, the K. Lisa Yang Brain-Body Center, part of the Yang Tan Collective at MIT, Broad Institute Programmable Therapeutics Gift Donors, the Pershing Square Foundation, J. and P. Poitras, and an EMBO Postdoctoral Fellowship.

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