CIRM Scholar Helen Fong on Stem Cells and Brain Disease

Helen Fong, CIRM Scholar and Research Scientist at the Gladstone Institutes

Helen Fong, CIRM Scholar and Research Scientist at the Gladstone Institutes

Meet another one of our talented CIRM Scholars, Helen Fong. She is currently a Research Scientist at the Gladstone Institutes and did her graduate work at the University of California, Irvine. Her passions include stem cells, disease modeling, and playing with differentiation protocols – the processes that tell stem cells to mature into specific tissues. As a CIRM Scholar, part of our educational training programs, Helen published four articles where she was listed as the first author. Her most recent one was a stellar study published in Stem Cell Reports using induced pluripotent stem cells (iPSCs) to model and understand a nerve cell-destroying brain disease called frontotemporal dementia.

We interviewed Helen to learn more about her work in stem cell research.


Q: What was your graduate school research on?

HF: I did my graduate work in the lab of Dr. Peter Donovan, who is a prominent germ cell and stem cell scientist, and was newly recruited to UCI when I began my studies. I was his first graduate student from UCI. Dr. Donovan’s research was focused on understanding the regulation of early human development using embryonic stem cells (ESCs) and how to improve human pluripotent stem cell culture. He was also interested in understanding the biological mechanisms that keep stem cells pluripotent (the ability to become all the other cell types in the body) and the genetic factors that are important for maintaining pluripotency. My graduate research was on understanding the basic biology of human ESCs. Specifically, I studied the role of the gene Sox2 in maintaining stem cell pluripotency and self renewal in human ESCs.

Q: What about your postdoctoral research?

HF: After my PhD, I decided to continue to work with stem cells because I knew that the field would continue to grow. There was still so much to be learned about these unique cells. I also genuinely enjoyed working with stem cells and couldn’t imagine not seeing them every day. I realized that I had a solid understanding of the basic biology of ESCs, but I wanted to use stem cells to study human disease. This ability is one of the huge selling points of working with human induced pluripotent stem cells (iPSCs) [which are created by reprogramming adult cells back to a pluripotent state]. The Gladstone Institutes was an excellent place to continue my training and to begin using iPSCs to understand neurological disease. I joined Dr. Yadong Huang’s lab in 2011 and am currently using human iPSCs to study brain degenerative diseases including frontotemporal dementia (FTD), progressive supranuclear palsy (PSP), and Alzheimer’s disease (AD).

My recent publication in Stem Cell Reports used human iPSCs from a patient with FTD as a model to understand the mechanisms behind this condition. This patient carried a rare genetic mutation in the MAPT gene called TAU-A152T. Several studies have reported a number of patients with this specific mutation that could put them at risk for developing FTD, PSP, and AD. However, it wasn’t clear what this mutation was doing to cause these disorders.

One of the ways you can study neurodegenerative diseases is using stem cells derived from patients harboring the disease causing mutations. We obtained human iPSCs made from the skin cells of a patient with FTD and this TAU mutation. I then used zinc finger nuclease (ZFN) genome editing technology to genetically correct the mutation back to the wild type (normal) sequence to see if removing this mutation in the patient iPSCs would generate healthier neurons (nerve cells) that don’t have symptoms of FTD. I was able to study the disease-causing effects of the TAU mutation by comparing healthy neurons I made from the corrected (normal) iPSC line to diseased neurons made from the TAU mutant iPSC line.

Neurons generated from FTD patient iPSCs. (Image courtesy of Helen Fong)

Neurons generated from FTD patient iPSCs. (Image courtesy of Helen Fong)

The neurons that I differentiated from the iPSCs carrying the TAU mutation showed an increase in TAU protein fragmentation [meaning the protein gets degraded and isn’t present in its normal form], an abnormal characteristic that can be associated with FTD and AD. We didn’t see this phenomenon in the neurons from the corrected (normal) human iPSCs, indicating that removal of this TAU mutation could improve the symptoms of these diseases. These results were exciting because we now had a culprit for what could be causing disease in these patients with this mutation. There is still much to be learned about the mechanisms of this mutation and the iPSCs have been an invaluable resource.

Q: What was your experience like as a CIRM scholar?

HF: CIRM has funded me for almost all of my stem cell training and research. I got my first CIRM training grant as a graduate student at UCI in 2006 and was funded for three years as a postdoc at the Gladstone. So I have CIRM to thank for all of my training.

When I first started out as a CIRM scholar, I believe I was part of one of their earlier pre-doctoral training grant programs. As the program expanded, I got to meet many of the other trainees at CIRM research conferences and interact with prominent stem cell scientists in the area. This was an incredible experience because I was exposed to stem cell research outside of my own institute, and I was able to meet all the big players in the field!

CIRM has also been very generous and provided me a travel allowance to attend any scientific conference of my choice. Over the years, I’ve gone to a lot of conferences nationally and internationally including ISSCR (International Society for Stem Cell Research), Keystone symposia, and the Society for Neuroscience (SfN). I have given scientific talks both at Keystone and SfN, and they proved to be excellent exposure for my work as well as a good place to get feedback. Another one of my favorite perks was the ability to purchase reagents for my own work at my own discretion, which gave me some freedom in dictating which direction I wanted my project to go. If I wanted to study a particular protein and needed a specific antibody to do that, I was able to get it with my CIRM funding.

Q: What’s next for your career?

HF: Currently, I am hoping to wrap up the project I am working on in the lab right now and generate a publication. I plan to continue to work on stem cells in the next step of my career and to work on challenging and cutting-edge projects. I feel fortunate for all the training and resources that I’ve received that got me to where I am today, and I hope to pass on many of my skills and knowledge to budding, young scientists.

Q: What is your favorite thing about being a scientist?

HF: I really enjoy the fact that I have so much control over the fate of my stem cells. They have the ability to turn into almost any cell type, and we’ve developed so many protocols to guide them into the exact cell type we want. They don’t always behave, but I think figuring out the personality of each and every cell line is part of the fun.


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From Stem Cells to Stomachs: Scientists Generate 3D, Functioning Human Stomach Tissue

The human stomach can be a delicate organ. For example, even the healthiest stomach can be compromised by H. pylori bacteria—a tiny but ruthless pathogen which has shown to be linked to both peptic ulcer disease and stomach cancer.

The best way to study how an H. pylori infection leads to conditions like cancer would be to recreate that exact environment, right down to the stomach itself, in the lab. But that task has proven far more difficult than originally imagined.

Part of a miniature stomach grown in the lab, stained to reveal various cells found in normal human stomachs [Credit: Kyle McCracken]

Part of a miniature stomach grown in the lab, stained to reveal various cells found in normal human stomachs [Credit: Kyle McCracken]

But now, scientists at the Cincinnati Children’s Hospital Medical Center and the University of Cincinnati College of Medicine have successfully grown functional, human stomach tissue in a dish—the first time such a feat has been accomplished.

Further, they were then able to test how human stomach tissue reacts to an invasion by H. pylori—a huge leap forward toward one day developing treatments for potentially deadly stomach disease.

Reporting in today’s issue of the journal Nature, senior author Jim Wells describes his team’s method of turning human pluripotent stem cells into stomach cells, known as gastric cells. Wells explained the importance of their breakthrough in a news release:

“Until this study, no one had generated gastric cells from human pluripotent stem cells. In addition, we discovered how to promote formation of three-dimensional gastric tissue with complex architecture and cellular composition.”

The team called this stomach tissue gastric organoids, a kind of ‘mini-stomach’ that mimicked the major cellular processes of a normal, functioning human stomach. Developing a human model of stomach development—and stomach disease—has long been a goal among scientists and clinicians, as animal models of the stomach did not accurately reflect what would be happening in a human stomach.

In this study, the research team identified the precise series of steps that can turn stem cells into gastric cells. And then they set these steps in motion.

Over the course of a month, the team coaxed the formation of gastric organoids that measured less than 1/10th of one inch in diameter. But even with this small size, the team could view the cellular processes that drive stomach formation—and discover precisely what happens when that process goes awry.

But what most intrigued the researchers, which also included first author University of Cincinnati’s Kyle McCracken, was how quickly an H. pylori infection impacted the health of the stomach tissue.

“Within 24 hours, the bacteria had triggered biochemical changes in the organ,” said McCracken.

According to McCracken, as the H. pylori infection spread from cell to cell, the researchers also recorded the activation of c-Met, a gene known to be linked to stomach cancer—further elucidating the relationship between H. pylori and this form of stomach disease.

Somewhat surprisingly, little was known about how gastric cells play a role in obesity-related diseases, such as type 2 diabetes. But thanks to Wells, McCracken and the entire Cincinnati Children’s research team—we are that much closer to shedding light on this process.

Wells also credits his team’s reliance on years of preliminary data performed in research labs around the world with helping them reach this landmark:

“This milestone would not have been possible if it hadn’t been for previous studies from many other basic researchers on understanding embryonic organ development.”