Bringing embryonic stem cell transplants closer to reality by quieting the immune response

A novel way of suppressing the immune system could make transplants of human embryonic stem cells a clinical possibility, according to new research by Stanford stem cell scientists.

Human embryonic stem cells (hESC) offer a tantalizing prospect for new therapies, but first we have to figure out how to get them past our immune system’s defenses. Stem cell scientists had initially thought embryonic stem cells might fly under the immune system’s radar, but a few years ago, they were surprised to find that, much like organ transplants, hESC provoke a rapid response when transplanted into a mouse’s body. When transplanted into a mouse, hESCs all died within a few days, according to previous work by the same team at Stanford, led by Joseph Wu.

But in a study published last week in the scientific journal, Stem Cells, the team used a pair of antibodies that blocked normal T-cell activation – the cells responsible for mounting the attack on foreign particles. This method worked better than the drugs traditionally used to suppress immune responses to organ transplants.

But unlike organ transplant drugs, which often need to be taken for the rest of a transplant recipient’s life, the dual-antibody treatment for hESC transplants was only needed for about a week.

On their blog, Stanford quoted Wu talking about the issue of getting the body to accept a transplant of cells derived from embryonic stem cells:

“Regenerative therapies hold great clinical promise, particularly for patients with damaged hearts and end-stage heart failure. But, surprisingly, promoting long-term stem cell graft acceptance is a much more formidable task than is supporting host acceptance of a vascularized solid organ such as a heart.”

These initial results are good news, but much more work is needed to find out if this treatment will work the same way in people as it does in mice. If the technique is effective in humans, it will help advance Wu’s ongoing work developing stem therapies for heart disease.

CIRM funding: Joseph Wu (DR2-05394, TR3-05556)

Rina Shaikh-Lesko

Through their lens: Margaret Shen studies a blood disease, learns that research is social

This summer we’re sponsoring high school interns in stem cell labs throughout California. We asked those students to contribute to our Instagram photos and YouTube videos about life in the lab, and write about their experiences.

Margaret Shen, is originally from Fremont, California. She will be attending Stanford this coming fall. Over the summer, she has interned at the City of Hope with Dr. Ren-Jang Lin’s lab in the Department of Cellular and Molecular Biology. One fun fact is that she loves building bikes in her spare time!

CIRM Creativity Award high school summer interns at City of Hope

The research project I worked on this summer was a branch of my lab’s overarching goal to study myelodysplastic syndrome (MDS). MDS is a blood disorder which causes deregulation of hematopoiesis and is often a precursor to acute myeloid leukemia. There are around 13,000 new cases a year in the U.S., and this number is expected to rise as the population ages. The mutants (P95H/L/R) of the pre-mRNA splicing gene SRSF2 are known to be specific to MDS; they are found in 9-15% of MDS patients. SRSF2 itself is a serine/arginine rich protein that helps to recognize the 3’ splice site of introns and stabilize the exon defined complex. One goal of this project was to determine whether these mutants would cause changes in alternative splicing. We isolated RNA from a TF-1 cell line that contained a Tet-On system to selectively activate the transcription of either wildtype or P95H/L/R SRSF2. We then used reverse transcriptase to make complementary DNA from the RNA template. PCR was used to find variations in splicing for selected genes. Caspase 8, associated with apoptosis, and CDC25C, involved in cell cycle mediation, had visible changes in alternative splicing based on ImageJ gel analysis. Other genes, such as TRA2A and IRF-1, showed no visible changes in alternative splicing for our gel images.

The second goal was to design a viral vector that could be used to observe the effects of SRSF2 mutations in a stem cell line. Because the use of a Tet-On system with doxycycline would cause changes in differentiation, we had to construct a new lentiviral vector with a constitutive promoter so that SRSF2 downstream would always be transcribed. We used PCR to isolate the SRSF2 wildtype and P95H/L/R inserts, and overlap-extension PCR to create the backbone with a constitutive promoter. This was followed with a restriction digest to make the ends of both compatible, then a subsequent overnight ligation. We are currently attempting to transform the ligation into DH5α competent cells. In the meantime, we are also about to start our first culture of human embryonic stem cells. We hope to be able to transduce our vector into these stem cells and observe if there are any changes in differentiation.

Still, this research experience has been more to me than just hardcore science or picking up benchwork skills. While I’ve always been a fan of science, a large part of why research interests me is the people I work with. The quirky stories they tell as the PCRs run in the background are just as interesting as the science behind our work. I think that many people turn away from research because they fear that it’s a quiet, lonely career involving little contact with the outside world. My experience this summer has shown me that it’s quite the opposite; without other people to consult with about interesting gel results or failed transfections, research just isn’t the same. Sometimes we’ve even debated the ethics of famous experiments or laws concerning research and medicine; it reminds me that human interaction is still a very integral component of the scientific community.

Margaret Shen

Margaret submitted this video about her summer:

Through their lens: Ted Zhu learns the thrill of the "aha!" moment while working on blood cancer

This summer we’re sponsoring high school interns in stem cell labs throughout California. We asked those students to contribute to our Instagram photos and YouTube videos about life in the lab, and write about their experiences.

Ted Zhu will be a junior at Walnut High School.  He works in Dr. Ren-Jang Lin’s lab, where he is designing a site-specific nuclease to study stem cell differentiation problems in myelodysplasia, a form of blood cancer. Ted loves watching sports; his favorite teams are the Steelers, Seahawks, Angels, and Lakers. He also loves nature and enjoys studying forestry as one of his hobbies.

I have an “addiction” to science. It’s that feel-good, bubbly rush of euphoria that shoots across my body, giving me tingling sensations across my arm and a light-headed feeling that makes me feel like I’m floating among the clouds.

I giggle.

“I’ve got it!”

More giggling.

Man, how I love science.

Get the good grades, get the good college, get the good job, and get the big bucks. That’s more or less the mantra that’s been instilled upon my fellow students and me in high school. But there are only so many spots in good colleges and companies, and so naturally, getting those spots entails intense competition. We scratch and claw to get those 4.0’s and 2400’s and fight our way to rack up numerous awards in our attempts to impress admissions officers and prospective employers. And while we absolutely hate the sleepless nights spent studying and stressing, we’re always hit upside the head as we realize that if we want to get the good college, the good job, and the big bucks, we’ve gotta chug on in this slugfest.

But maybe there’s another path to getting the good college and the good job? Or maybe the final end goal isn’t to get big bucks? It’s actually to be happy? Just simply, happy?

Dr. Eugene Roberts probably knows a bit about being happy. At 93 years old, the esteemed director emeritus of neurobiochemistry of City of Hope and founder of this great summer program that I’m a part of here at City of Hope, says the only reason why he still works here is because he’s always discovering more in his lab, and that learning process, quite simply, makes him happy.

The seminal moment of my summer internship so far was hearing Dr. Eugene Roberts talk with Dr. Mark Wise, a professor of theoretical physics at Caltech. Essentially, the topic at hand was “Why do I love science?” And these two great minds, these two great geniuses both pointed to the same reason: that “aha!” moment, that lightbulb moment when our breakthroughs in the lab provide a glimpse, no matter how big or how small, into our understanding of how the world functions. And it’s that lightbulb moment that lights us up to give us that rush of euphoria and burst of joy that nothing else can bring. As soon as they mentioned that feeling, I could identify with what they meant.

For me, it extends a bit past that as well. I constantly feel that I have a duty, as a human being, to aid my fellow human beings who need help. Watching my own parents suffer through cancer for the last 5 years has left an indelible mark in my mind on the horrors of what cancer can bring. And so I am committed to being a part of the process that may someday rid the world of those horrors I experienced.

Furthermore, I’ve been lucky and privileged enough to have been blessed with scores of opportunities to help me pursue my passion of science. And as people give me these opportunities that I so desperately want and need to keep voracious appetite of learning sated, I feel obliged to pass on the love. Whenever I feel crushed by the mind-boggling stress or frustration of failure in my lab, I remind myself that somewhere out there in the world, some destitute, starving, and emaciated kid could be the next Richard Feynman or Jonas Salk were he or she given the chance. I’ll also then remind myself that what I do may be able to help future physicians and researchers save a life someday or ease the pain for some chronically afflicted patient. And just that once life that can be changed will be worth every single hair-tearing moment I have, or ever will experience.

I think I’ve finally come to the trite but true realization that maybe what really matters is not the money and the prestige (or in my case right now, the grades and awards), but doing something I really love and care about. It is doing omething that satisfies both my intellectual side and my emotional side. I’m constantly reminded that being a researcher won’t earn me much money, but I honestly couldn’t give a lab rat’s fart about how much money I’ll make as a researcher. As long as I love it, and I can (somewhat) adequately pay off my future bills and provide for my parents, then I think that’ll be the life for me.

Initially, I applied to City of Hope because I thought it would look great on my college applications. But as the summer comes to a close, I realize I’ve enjoyed my time here at City of Hope this summer for all the reasons I’ve just mentioned above. And what’s given me an immense satisfaction is that I’ve enjoyed working here because I love it.

Not because Harvard will love it.

Thanks Dr. Roberts and Dr. Wise.

Ted Zhu

Ted submitted this video about his summer: