Stem cell summer: high school students document internships via social media, Part 3

Today we share our third and final pair of social media awards from CIRM’s 2018 SPARK (Summer Program to Accelerate Regenerative medicine Knowledge) program, a 6-12 week summer internship program that provides hands-on stem cell research training to high school students throughout California.

AnthonyTan

CIRM SPARK 2018 Best Instagram Post winner by Caltech SPARK intern Anthony Tan

As part of their curriculum, the students were asked to write a blog and to post Instagram photos (follow #cirmsparklab) to document their internship experiences. Several CIRM team members selected their favorite entries and presented awards to the winning interns at the SPARK Student Conference earlier this month at UC Davis.

The two winners featured today are Caltech SPARK student, Anthony Tan – a senior at John A. Rowland High School – one of the Instagram Award winners (see his Instagram post above) and UCSF SPARK student Gennifer Hom – a senior at Ruth Asawa School of the Arts – one of the Blog Award winners. Read her blog below. (To learn about the other 2018 social media winners, see our previous blog posts here and here.)

Best Blog Award:
My SPARK 2018 summer stem cell research internship experience
By Gennifer Hom

genniferhom

Gennifer Hom

When I was seven, I remember looking up at the stars, I stared hard at the moon through my car window, thinking that it only revolves around me as it followed me home. I later learned in class that we rotate around the sun, as gravity holds the spinning planets in place, simultaneously, the moon revolves around the earth. Out of nowhere, I abruptly felt an actual light bulb switched on above my head once I learned how day and night came. Overcome with curiosity,“ Where did the Big Bang take place? When will my Big Bang happen?”

My interest dissipated as I entered into my high school career. I was struck with incoherence, an inconsistency to my thoughts, as I leaned my shoulder against the wall—for I had already decided to let my fatigue to take over. I felt lacking, unconfident in my abilities even to solve a simple balance chemical equation in chemistry class. Science was not my forte. I could never see myself working in a lab setting.

Still, a spark within me still held onto that childhood curiosity of mine. I remember sitting on the bus on my way to school reading about stem cells, which were fascinating to me. We can use these little cells for so many scientific research.

My Big Bang unfolded when I was accepted into the UCSF SEP internship program. I
studied the human-specific population of cortical neural stem cells and evaluated the signaling mechanisms that govern the formation of their identity. Through my performance, I am also contributing to this phenomenal study, helping my community by potentially providing information to help cure mental illnesses. At times, the results of our data did not come out as we wanted it to be. The staining went wrong, and the images were lacking. I would have to repeat the experiment or troubleshoot on the spot continually. However, it’s all a learning process. Even if I do get beautiful image stainings, I still need to repeat the experiments to confirm my results.

Learning was not the only side that is needed under this program. CIRM encouraged us to share our internship experiences on social media. I posted once a week on my studies, what I’ve learned, and how I could teach my viewers about this new research I am performing. I remember in one of the first few meetings we had, where we had to share our research with our peers, “ I can actually understand your studies,” a friend of mine claimed.

I felt powerful, in a sense, that I was able to communicate my knowledge to others to help them understand and teach my study. When I talk to my family and friends about my summer, I feel confident in my ability to comprehend these complex ideas. I could see myself researching, engineering, and fighting for a solution. I want to find the best form of gene therapy, and map each neuron of the brain. Through this two month program, science has become a new passion for me, a cornerstone of my new academic pursuits. It strengthened my theoretical knowledge and gave me an experience where I witnessed the real world laboratory setting. Not only did I learn the fundamental techniques of immunohistochemistry and microscopy, but I was able to receive encouraging advice from the scientists in the Kriegsteins lab and especially my mentor, Madeline Andrews. The experience in a lab comforted me by the idea of the never-ending changes that lured me to a world of thought and endless potential.

Stem cell stories that caught our eye: update on Capricor’s heart attack trial; lithium on the brain; and how stem cells do math

Capricor ALLSTARToday our partners Capricor Therapeutics announced that its stem cell therapy for patients who have experienced a large heart attack is unlikely to meet one of its key goals, namely reducing the scar size in the heart 12 months after treatment.

The news came after analyzing results from patients at the halfway point of the trial, six months after their treatment in the Phase 2 ALLSTAR clinical trial which CIRM was funding. They found that there was no significant difference in the reduction in scarring on the heart for patients treated with donor heart-derived stem cells, compared to patients given a placebo.

Obviously this is disappointing news for everyone involved, but we know that not all clinical trials are going to be successful. CIRM supported this research because it clearly addressed an unmet medical need and because an earlier Phase 1 study had showed promise in helping prevent decline in heart function after a heart attack.

Yet even with this failure to repeat that promise in this trial,  we learned valuable lessons.

In a news release, Dr. Tim Henry, Director of the Division of Interventional Technologies in the Heart Institute at Cedars-Sinai Medical Center and a Co-Principal Investigator on the trial said:

“We are encouraged to see reductions in left ventricular volume measures in the CAP-1002 treated patients, an important indicator of reverse remodeling of the heart. These findings support the biological activity of CAP-1002.”

Capricor still has a clinical trial using CAP-1002 to treat boys and young men developing heart failure due to Duchenne Muscular Dystrophy (DMD).

Lithium gives up its mood stabilizing secrets

As far back as the late 1800s, doctors have recognized that lithium can help people with mood disorders. For decades, this inexpensive drug has been an effective first line of treatment for bipolar disorder, a condition that causes extreme mood swings. And yet, scientists have never had a good handle on how it works. That is, until this week.

evan snyder

Evan Snyder

Reporting in the Proceedings of the National Academy of Sciences (PNAS), a research team at Sanford Burnham Prebys Medical Discovery Institute have identified the molecular basis of the lithium’s benefit to bipolar patients.  Team lead Dr. Evan Snyder explained in a press release why his group’s discovery is so important for patients:

“Lithium has been used to treat bipolar disorder for generations, but up until now our lack of knowledge about why the therapy does or does not work for a particular patient led to unnecessary dosing and delayed finding an effective treatment. Further, its side effects are intolerable for many patients, limiting its use and creating an urgent need for more targeted drugs with minimal risks.”

The study, funded in part by CIRM, attempted to understand lithium’s beneficial effects by comparing cells from patient who respond to those who don’t (only about a third of patients are responders). Induced pluripotent stem cells (iPSCs) were generated from both groups of patients and then the cells were specialized into nerve cells that play a role in bipolar disorder. The team took an unbiased approach by looking for differences in proteins between the two sets of cells.

The team zeroed in on a protein called CRMP2 that was much less functional in the cells from the lithium-responsive patients. When lithium was added to these cells the disruption in CRMP2’s activity was fixed. Now that the team has identified the molecular location of lithium’s effects, they can now search for new drugs that do the same thing more effectively and with fewer side effects.

The stem cell: a biological calculator?

math

Can stem cells do math?

Stem cells are pretty amazing critters but can they do math? The answer appears to be yes according to a fascinating study published this week in PNAS Proceedings of the National Academy of Sciences.

Stem cells, like all cells, process information from the outside through different receptors that stick out from the cells’ outer membranes like a satellite TV dish. Protein growth factors bind those receptors which trigger a domino effect of protein activity inside the cell, called cell signaling, that transfers the initial receptor signal from one protein to another. Ultimately that cascade leads to the accumulation of specific proteins in the nucleus where they either turn on or off specific genes.

Intuition would tell you that the amount of gene activity in response to the cell signaling should correspond to the amount of protein that gets into the nucleus. And that’s been the prevailing view of scientists. But the current study by a Caltech research team debunks this idea. Using real-time video microscopy filming, the team captured cell signaling in individual cells; in this case they used an immature muscle cell called a myoblast.

goentoro20170508

Behavior of cells over time after they have received a Tgf-beta signal. The brightness of the nuclei (circled in red) indicates how much Smad protein is present. This brightness varies from cell to cell, but the ratio of brightness after the signal to before the signal is about the same. Image: Goentoro lab, CalTech.

To their surprise the same amount of growth factor given to different myoblasts cells led to the accumulation of very different amounts of a protein called Smad3 in the cells’ nuclei, as much as a 40-fold difference across the cells. But after some number crunching, they discovered that dividing the amount of Smad3 after growth factor stimulation by the Smad3 amount before growth stimulation was similar in all the cells.

As team lead Dr. Lea Goentoro mentions in a press release, this result has some very important implications for studying human disease:

“Prior to this work, researchers trying to characterize the properties of a tumor might take a slice from it and measure the total amount of Smad in cells. Our results show that to understand these cells one must instead measure the change in Smad over time.”

Young Minds Shine Bright at the CIRM SPARK Conference

SPARK students take a group photo with CIRM SPARK director Karen Ring.

SPARK students take a group photo with CIRM SPARK director Karen Ring.

Yesterday was one of the most exciting and inspiring days I’ve had at CIRM since I joined the agency one year ago. We hosted the CIRM SPARK conference which brought together fifty-five high school students from across California to present their stem cell research from their summer internships.

The day was a celebration of their accomplishments. But it was also a chance for the students to hear from scientists, patient advocates, and clinicians about the big picture of stem cell research: to develop stem cell treatments and cures for patients with unmet medical needs.

Since taking on the role of the CIRM SPARK director, I’ve been blown away by the passion, dedication, and intelligence that our SPARK interns have shown during their short time in the lab. They’ve mastered techniques and concepts that I only became familiar with during my PhD and postdoctoral research. And even more impressive, they eloquently communicated their research through poster presentations and talks at the level of professional scientists.

During their internships, SPARK students were tasked with documenting their research experiences through blogs and social media. They embraced this challenge with gusto, and we held an awards ceremony to recognize the students who went above and beyond with these challenges.

I’d like to share the winning blogs with our readers. I hope you find them as inspiring and motivating as I do. These students are our future, and I look forward to the day when one of them develops a stem cell treatment that changes the lives of patients. 

Andrew Choi

Andrew Choi

Andrew Choi, Cedars-Sinai SPARK student

Am I crying or is my face uncontrollably sweating right now? I think I am doing both as I write about my unforgettable experiences over the course of the past 6 weeks and finalize my poster.

As I think back, I am very grateful for the takeaways of the research field, acquiring them through scientific journals, lab experiments with my mentor, and both formal and informal discourses. It seems impossible to describe all the episodes and occurrences during the program in this one blog post, but all I can say is that they were all unique and phenomenal in their own respective ways.

Gaining new perspectives and insights and being acquainted with many of the techniques, such as stereology, immunocytochemistry and immunohistochemistry my peers have utilized throughout their careers, proved to me the great impact this program can make on many individuals of the younger generation.

CIRM SPARK not only taught me the goings on behind the bench-to-bedside translational research process, but also morals, work ethics, and effective collaboration with my peers and mentors. My mentor, Gen, reiterated the importance of general ethics. In the process of making my own poster for the program, her words resonate even greater in me. Research, education, and other career paths are driven by proper ethics and will never continue to progress if not made the basic standard.

I am thankful for such amazing institutions: California Institute of Regenerative Medicine (CIRM) and Cedars-Sinai Medical Center for enabling me to venture out into the research career field and network. Working alongside with my fellow seven very brilliant friends, motivated me and made this journey very enjoyable. I am especially thankful my mentor, Gen, for taking the time to provide me with the best possible resources, even with her busy ongoing projects. She encouraged me to be the best that I am.

I believe, actually, I should say, I KNOW Cedars-Sinai’s CIRM SPARK program does a SUPERB and astounding job of cultivating life-long learners and setting exceptional models for the younger generation. I am hoping that many others will partake in this remarkable educational program.

I am overall very blessed to be part of a successful summer program. The end of this program does not mark the end of my passions, but sparks them to even greater heights.

Jamey Guzman

Jamey Guzman

Jamey Guzman, UC Davis SPARK student

When I found out about this opportunity, all I knew was that I had a fiery passion for learning, for that simple rush that comes when the lightbulb sputters on after an unending moment of confusion. I did not know if this passion would translate into the work setting; I sometimes wondered if passion alone would be enough to allow me to understand the advanced concepts at play here. I started at the lab nervous, tentative – was this the place for someone so unsure exactly what she wanted to be ‘when she grew up,’ a date now all too close on the horizon? Was I going to fit in at this lab, with these people who were so smart, so busy, people fighting for their careers and who had no reason to let a 16-year-old anywhere near experiments worth thousands of dollars in cost and time spent?

I could talk for hours about the experiments that I worked to master; about the rush of success upon realizing that the tasks now completed with confidence were ones that I had once thought only to belong to the lofty position of Scientist. I could fill pages and pages with the knowledge I gained, a deep and personal connection to stem cells and cell biology that I will always remember, even if the roads of Fate pull me elsewhere on my journey to a career.

The interns called the experience #CIRMSparkLab in our social media posts, and I find this hashtag so fitting to describe these last few months. While there was, of course, the lab, where we donned our coats and sleeves and gloves and went to work with pipets and flasks…There was also the Lab. #CIRMSparkLab is so much more than an internship; #CIRMSparkLab is an invitation into the worldwide community of learned people, a community that I found to be caring and vibrant, creative and funny – one which for the first time I can fully imagine myself joining “when I grow up.”

#CIRMSparkLab is having mentors who taught me cell culture with unerring patience and kindness. It is our team’s lighthearted banter across the biosafety cabinet; it is the stories shared of career paths, of goals for the present and the future. It is having mentors in the best sense of the word, trusting me, striving to teach and not just explain, giving up hours and hours of time to draw up diagrams that ensured that the concepts made so much sense to me.

#CIRMSparkLab is the sweetest ‘good-morning’ from scientists not even on your team, but who care enough about you to say hi, to ask about your projects, to share a smile. It is the spontaneity and freedom with which knowledge is dispensed: learning random tidbits about the living patterns of beta fish from our lab manager, getting an impromptu lecture about Time and the Planck Constant from our beloved professor as he passes us at lunch. It is getting into a passionate, fully evidence-backed argument about the merits of pouring milk before cereal that pitted our Stem Cell team against our Exosome team: #CIRMSparkLab is finding a community of people with whom my “nerdy” passion for learning does not leave me an oddball, but instead causes me to connect instantly and deeply with people at all ages and walks of life. And it is a community that, following the lead of our magnificent lab director, welcomed ten interns into their lab with open arms at the beginning of this summer, fully cognizant of the fact that we will break beakers, overfill pipet guns, drop gels, bubble up protein concentration assays, and all the while never stop asking, “Why? Why? Why? Is this right? Like this? WHY?”

I cannot make some sweeping statement that I now know at age 16 exactly what I want to do when I grow up. Conversely, to say I learned so much – or I am so grateful – or you have changed my life is simply not enough; words cannot do justice to those sentiments which I hope that all of you know already. But I can say this: I will never forget how I felt when I was at the lab, in the community of scientists. I will take everything I learned here with me as I explore the world of knowledge yet to be obtained, and I will hold in my heart everyone who has helped me this summer. I am truly a better person for having known all of you.

Thank you, #CIRMSparkLab. 

Adriana Millan

Adriana Millan

Adriana Millan, CalTech SPARK student

As children, we all grew up with the companionship of our favorite television shows. We enjoyed sitcoms and other animations throughout our childhood and even as adults, there’s no shame. The goofy and spontaneous skits we enjoyed a laugh over, yet we did not pay much attention to the lessons they attempted to teach us. As a child, these shows play crucial roles in our educational endeavors. We are immediately hooked and tune in for every episode. They spark curiosity, as they allow our imaginations to run wild. For me, that is exactly where my curiosity stemmed and grew for science over the years. A delusional young girl, who had no idea what the reality of science was like.

You expect to enter a lab and run a full day of experimentations. Accidentally mix the wrong chemicals and discover the cure for cancer. Okay, maybe not mix the incorrect chemicals together, I learned that in my safety training class. The reality is that working in a lab was far from what I expected — eye opening. Working alongside my mentor Sarah Frail was one of the best ways I have spent a summer. It was not my ideal summer of sleeping in until noon, but it was worthwhile.

My experience is something that is a part of me now. I talk about it every chance I get, “Mom, can you believe I passaged cells today!” It changed the way I viewed the principles of science. Science is one of the most valuable concepts on this planet, it’s responsible for everything and that’s what I have taken and construed from my mentor. She shared her passion for science with me and that completed my experience. Before when I looked at cells, I did not know exactly what I was supposed to observe. What am I looking at? What is that pink stuff you are adding to the plate?

However, now I feel accomplished. It was a bit of a roller coaster ride, with complications along the way, but I can say that I’m leaving this experience with a new passion. I am not just saying this to please the audience, but to express my gratitude. I would have never even looked into Huntington’s Disease. When I first arrived I was discombobulated. Huntington’s Disease? Now I can proudly say I have a grasp on the complexity of the disease and not embarrass my mentor my calling human cells bacteria – quite embarrassing in fact.  I’m a professional pipette handler, I work well in the hood, I can operate a microscope – not so impressive, I have made possibly hundreds of gels, I have run PCRs, and my cells love me, what else can I ask for.

If you are questioning what career path you are to take and even if it is the slightest chance it may be a course in science, I suggest volunteering in a lab. You will leave with your questioned answered. Is science for me? This is what I am leaving my experience with. Science is for me.

Other SPARK 2016 Awards

Student Speakers: Jingyi (Shelly) Deng (CHORI), Thomas Thach (Stanford)

Poster Presentations: Jerusalem Nerayo (Stanford), Jared Pollard (City of Hope), Alina Shahin (City of Hope), Shuling Zhang (UCSF)

Instagram Photos: Roxanne Ohayon (Stanford), Anna Victoria Serbin (CHORI), Diana Ly (UC Davis)

If you want to see more photos from the CIRM SPARK conference, check out our Instagram page @CIRM_Stemcells or follow the hashtag #CIRMSPARKLab on Instagram and Twitter.

Stem cell stories that caught our eye: turning on T cells; fixing our brains; progress and trends in stem cells; and one young man’s journey to recover from a devastating injury

Healthy_Human_T_Cell

A healthy T cell

Here are some stem cell stories that caught our eye this past week. Some are groundbreaking science, others are of personal interest to us, and still others are just fun.

Directing the creation of T cells. To paraphrase the GOP Presidential nominee, any sane person LOVES, LOVES LOVES their T cells, in a HUGE way, so HUGE. They scamper around the body getting rid of viruses and the tiny cancers we all have in us all the time. A CIRM-funded team at CalTech has worked out the steps our genetic machinery must take to make more of them, a first step in letting physicians turn up the action of our immune systems.

We have known for some time the identity of the genetic switch that is the last, critical step in turning blood stem cells into T cells, but nothing in our body is as simple as a single on-off event. The Caltech team isolated four genetic factors in the path leading to that main switch and, somewhat unsuspected, they found out those four steps had to be activated sequentially, not all at the same time. They discovered the path by engineering mouse cells so that the main T cell switch, Bcl11b, glows under a microscope when it is turned on.

“We identify the contributions of four regulators of Bcl11b, which are all needed for its activation but carry out surprisingly different functions in enabling the gene to be turned on,” said Ellen Rothenberg, the senior author in a university press release picked up by Innovations Report. “It’s interesting–the gene still needs the full quorum of transcription factors, but we now find that it also needs them to work in the right order.”

Video primer on stem cells in the brain.  In conjunction with an article in its August issue, Scientific American posted a video from the Brain Forum in Switzerland of Elena Cattaneo of the University of Milan explaining the basics of adult versus pluripotent stem cells, and in particular how we are thinking about using them to repair diseases in the brain.

The 20-minute talk gives a brief review of pioneers who “stood alone in unmarked territory.” She asks how can stem cells be so powerful; and answers by saying they have lots of secrets and those secrets are what stem cell scientist like her are working to unravel.  She notes stem cells have never seen a brain, but if you show them a few factors they can become specialized nerves. After discussing collaborations in Europe to grow replacement dopamine neurons for Parkinson’s disease, she went on to describe her own effort to do the same thing in Huntington’s disease, but in this case create the striatal nerves lost in that disease.

The video closes with a discussion of how basic stem cell research can answer evolutionary questions, in particular how genetic changes allowed higher organisms to develop more complex nervous systems.

kelley and kent

CIRM Science Officers Kelly Shepard and Kent Fitzgerald

A stem cell review that hits close to home.  IEEE Pulse, a publication for scientists who mix engineering and medicine and biology, had one of their reporters interview two of our colleagues on CIRM’s science team. They asked senior science officers Kelly Shepard and Kent Fitzgerald to reflect on how the stem cell field has progressed based on their experience working to attract top researchers to apply for our grants and watching our panel of outside reviewers select the top 20 to 30 percent of each set of applicants.

One of the biggest changes has been a move from animal stem cell models to work with human stem cells, and because of CIRM’s dedicated and sustained funding through the voter initiative Proposition 71, California scientists have led the way in this change. Kelly described examples of how mouse and human systems are different and having data on human cells has been critical to moving toward therapies.

Kelly and Kent address several technology trends. They note how quickly stem cell scientists have wrapped their arms around the new trendy gene editing technology CRISPR and discuss ways it is being used in the field. They also discuss the important role of our recently developed ability to perform single cell analysis and other technologies like using vessels called exosomes that carry some of the same factors as stem cells without having to go through all the issues around transplanting whole cells.

“We’re really looking to move things from discovery to the clinic. CIRM has laid the foundation by establishing a good understanding of mechanistic biology and how stem cells work and is now taking the knowledge and applying it for the benefit of patients,” Kent said toward the end of the interview.

jake and family

Jake Javier and his family

Jake’s story: one young man’s journey to and through a stem cell transplant; As a former TV writer and producer I tend to be quite critical about the way TV news typically covers medical stories. But a recent story on KTVU, the Fox News affiliate here in the San Francisco Bay Area, showed how these stories can be done in a way that balances hope, and accuracy.

Reporter Julie Haener followed the story of Jake Javier – we have blogged about Jake before – a young man who broke his spine and was then given a stem cell transplant as part of the Asterias Biotherapeutics clinical trial that CIRM is funding.

It’s a touching story that highlights the difficulty treating these injuries, but also the hope that stem cell therapies holds out for people like Jake, and of course for his family too.

If you want to see how a TV story can be done well, this is a great example.

California high schoolers SPARK interest in stem cell research through social media

I have a job for you today and it’s a fun one. Open your Instagram app on your phone. If you’re not an Instagrammer, don’t worry, you can access the website on your computer.

Do you have it open? OK now type in the hashtag #CIRMSparkLab and click on it.

What you’ll find is around 200 posts of the most inspiring and motivating pictures of stem cell research that I’ve seen. These pictures are from high school students currently participating in the CIRM summer SPARK program, one of our educational programs, which has the goal to train the next generation of stem cell scientists.

The SPARK program offers California high school students an invaluable opportunity to gain hands-on training in regenerative medicine at some of the finest stem cell research institutes in the state. And while they gain valuable research skills, we are challenging them to share their experiences with the general public through blogging and social media.

Communicating science to the public is an important mission of CIRM, and the SPARK students are excelling at this task by posting descriptive photos on Instagram that document their internships. Some of them are fun lab photos, while others are impressive images of data with detailed explanations about their research projects.

Below are a few of my favorite posts so far this summer. I’ve been so inspired by the creativity of these posts that we are now featuring some of them on the @CIRM_Stemcells account. (Yes this is a shameless plug for you to follow us on Instagram!).

City of Hope SPARK program.

Screen Shot 2016-07-13 at 11.15.14 AM

Screen Shot 2016-07-13 at 11.17.24 AM

Screen Shot 2016-07-13 at 11.16.59 AM

Screen Shot 2016-07-13 at 11.23.51 AM

Screen Shot 2016-07-13 at 11.17.43 AM

I encourage you all to follow our talented SPARK students this summer as they continue to document their exciting journeys on Instagram. These students are our future and supporting their training and education in stem cell research is an honor for CIRM and a vital step towards achieving our mission of accelerating stem cell treatments to patients with unmet medical needs.

Stay tuned for more blog coverage about SPARK and our other educational program, the Bridges to Stem Cell Research program for undergraduate and master-level students. The annual Bridges conference that brings all the students together to present their research will be held next week, and the SPARK conference is on August 8th both in Berkeley.

T cell fate and future immunotherapies rely on a tag team of genetic switches

Imagine if scientists could build microscopic smart missiles that specifically seek out and destroy deadly, hard-to-treat cancer cells in a patient’s body? Well, you don’t have to imagine it actually. With techniques such as chimeric antigen receptor (CAR) T therapy, a patient’s own T cells – immune system cells that fight off viruses and cancer cells – can be genetically modified to produce customized cell surface proteins to recognize and kill the specific cancer cells eluding the patient’s natural defenses. It is one of the most exciting and promising techniques currently in development for the treatment of cancer.

Human T Cell (Wikipedia)

Human T Cell (Wikipedia)

Although there have been several clinical trial success stories, it’s still early days for engineered T cell immunotherapies and much more work is needed to fine tune the approach as well as overcome potential dangerous side effects. Taking a step back and gaining a deeper understanding of how stem cells specialize into T cells in the first place could go a long way into increasing the efficiency and precision of this therapeutic strategy.

Enter the CIRM-funded work of Hao Yuan Kueh and others in Ellen Rothenberg’s lab at CalTech. Reporting yesterday in Nature Immunology, the Rothenberg team uncovered a time dependent array of genetic switches – some with an ON/OFF function, others with “volume” control – that together control the commitment of stem cells to become T cells.

Previous studies have shown that the protein encoded by the Bcl11b gene is the key master switch that when activated sets a “no going back” path toward a T cell fate. A group of other genes, including Runx1, TCF-1 and GATA-3 are known to play a role in activating Bcl11b. The dominant school of thought is that these proteins gradually accumulate at the Bcl11b gene and once a threshold level is achieved, the proteins combine to enable the Bcl11b activation switch to flip on. However, other studies suggest that some of these proteins may act as “pioneer” factors that loosen up the DNA structure and allow the other proteins to readily access and turn on the Bcl11b gene. Figuring out which mechanism is at play is critical to precisely manipulating T cell development through genetic engineering.

To tease out the answer, the CalTech team engineered mice such that cells with activated Bcl11b would glow which allows visualizing the fate of single cells. We reached out to Dr. Kueh on the rationale for this experimental approach:

Hao Yuan Kueh, CalTech

Hao Yuan Kueh, CalTech

“To fully understand how genes are controlled, we need to watch them turn on and off in single, living cells over time.  As cells in our body are unique and different from one another, standard measurement methods, which average over millions of cells, often do not tell us the entire picture.”

The team examined the impact of inhibiting the T cell specific proteins GATA-3 and TCF-1 at different stages in T cell development in single cells. When the production of these two proteins were blocked in very early T cell progenitor (ETPs) cells, activation of Bcl11b was dramatically reduced. But that’s not what they observed when the experiment was repeated in a later stage of T cell development. In this case, blocking GATA-3 and TCF-1 had a much weaker impact on Bcl11b. So GATA-3 and TCF-1 are important for turning on Bcl11b early in T cell development but are not necessary for maintaining Bcl11b activation at later stages.

Inhibition of Runx1, on the other hand, did lead to a reduction in Bcl11b in these later T cell development stages. Making Runx1 levels artificially high conversely led to elevated Bcl11b in these cells.

Together, these results point to GATA-3 and TCF-1 as the key factors for turning on Bcl11b to commit cells to a T cell fate and then they hand off their duties to Runx1 to keep Bcl11b on and maintaining the T cell identity. Dr. Kuhn sums up the results and their implications this way:

“Our work shows that control of gene expression is very much a team effort, where some proteins flip the gene’s master ON-OFF switch, and others set its expression levels after it turns on…These results will help us generate customized T-cells to fight cancer and other diseases.  As T-cells are specialized to recognize and fight foreign agents in our body, this therapy strategy holds much promise for diseases that are difficult to treat with standard drug-based methods.  Also, these intricate gene regulation mechanisms are likely to be in play in other cell types in our body, not just T-cells, and so we believe our results will be widely relevant.”