Gastrointestinal Disease

Making transplants easier for kids, and charting a new approach to fighting solid tumors.

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Every year California performs around 100 kidney transplants in children but, on average, around 50 of these patients will have their body reject the transplant. These children then have to undergo regular dialysis while waiting for a new organ. Even the successful transplants require a lifetime of immunosuppression medications. These medications can prevent rejection but they also increase the risk of infection, gastrointestinal disease, pancreatitis and cancer.

Dr. Alice Bertaina and her team at Stanford University were awarded $11,998,188 to test an approach that uses combined blood stem cell (HSC) and kidney transplantation with the goal to improve outcomes with kidney transplantation in children. This approach seeks to improve on the blood stem cell preparation through an immune-based purification process.

In this approach, the donor HSC are transplanted into the patient in order to prepare for the acceptance of the donor kidney once transplanted. Donor HSC give rise to cells and conditions that re-train the immune system to accept the kidney. This creates a “tolerance” to the transplanted kidney providing the opportunity to avoid long-term need for medications that suppress the immune system.

Pre-clinical data support the idea that this approach could enable the patient to stop taking any immunosuppression medications within 90 days of the surgery.

Dr. Maria T. Millan, President and CEO of CIRM, a former pediatric transplant surgeon and tolerance researcher states that “developing a way to ensure long-term success of organ transplantation by averting immune rejection while avoiding the side-effects of life-long immunosuppression medications would greatly benefit these children.”

The CIRM Board also awarded $7,141,843 to Dr. Ivan King and Tachyon Therapeutics, Inc to test a drug showing promise in blocking the proliferation of cancer stem cells in solid tumors such as colorectal and gastrointestinal cancer.

Patients with late-stage colorectal cancer are typically given chemotherapy to help stop or slow down the progression of the disease. However, even with this intervention survival rates are low, usually not more than two years.

Tachyon’s medication, called TACH101, is intended to target colorectal cancer (CRC) stem cells as well as the bulk tumor by blocking an enzyme called KDM4, which cancer stem cells need to grow and proliferate.

In the first phase of this trial Dr. King and his team will recruit patients with advanced or metastatic solid tumors to assess the safety of TACH101, and determine what is the safest maximum dose. In the second phase of the trial, patients with gastrointestinal tumors and colorectal cancer will be treated using the dose determined in the first phase, to determine how well the tumors respond to treatment.  

The CIRM Board also awarded $5,999,919 to Dr. Natalia Gomez-Ospina and her team at Stanford University for a late-stage preclinical program targeting Severe Mucopolysaccharidosis type 1, also known as Hurler syndrome. This is an inherited condition caused by a faulty gene. Children with Hurler syndrome lack an enzyme that the body needs to digest sugar. As a result, undigested sugar molecules build up in the body, causing progressive damage to the brain, heart, and other organs. There is no effective treatment and life expectancy for many of these children is only around ten years.

Dr. Gomez-Ospina will use the patient’s own blood stem cells that have been genetically edited to restore the missing enzyme. The goal of this preclinical program is to show the team can manufacture the needed cells, to complete safety studies and to apply to the US Food and Drug Administration for an Investigational New Drug (IND), the authorization needed to begin a clinical trial in people.

Finally the Board awarded $20,401,260 to five programs as part of its Translational program. The goal of the Translational program is to support promising stem cell-based or gene projects that accelerate completion of translational stage activities necessary for advancement to clinical study or broad end use. Those can include therapeutic candidates, diagnostic methods  or devices and novel tools that address critical bottlenecks in research.

The successful applicants are:

APPLICATIONTITLEPRINCIPAL INVESTIGATOR – INSTITUTIONAMOUNT  
TRAN4-14124Cell Villages and Clinical Trial in a Dish with Pooled iPSC-CMs for Drug DiscoveryNikesh Kotecha — Greenstone Biosciences  $1,350,000
TRAN1-14003Specific Targeting Hypoxia Metastatic Breast Tumor with Allogeneic Off-the-Shelf Anti-EGFR CAR NK Cells Expressing an ODD domain of HIF-1αJianhua Yu — Beckman Research Institute of City of Hope  $6,036,002  
TRAN1-13983CRISPR/Cas9-mediated gene editing of Hematopoietic
stem and progenitor cells for Friedreich’s ataxia		Stephanie Cherqui — University of California, San Diego  $4,846,579
TRAN1-13997Development of a Gene Therapy for the Treatment of
Pitt Hopkins Syndrome (PHS) – Translating from Animal Proof of Concept to Support Pre-IND Meeting		Allyson Berent — Mahzi Therapeutics  $4,000,000
TRAN1-13996Overcoming resistance to standard CD19-targeted CAR
T using a novel triple antigen targeted vector		William J Murphy — University of California, Davis  $4,168,679

Stem cell agency invests in therapy using killer cells to target colorectal, breast and ovarian cancers

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While there have been some encouraging advances in treating cancer in recent decades, there are still many cancers that either resist treatment or recur after treatment. Today the governing Board of the California Institute for Regenerative Medicine (CIRM) approved investing in a therapy targeting some of these hard-to-treat tumors.

BioEclipse Therapeutics Inc. was awarded nearly $8M to test a therapy using immune cells loaded with a cancer-killing virus that targets cancer tissue but spares healthy tissue.

This is the 78th clinical trial funded directly by the Stem Cell Agency.

BioEclipse combines two approaches—an immune cell called a cytokine-induced killer (CIK) cell and a virus engineered to kill cancer cells called an oncolytic virus (OV)—to create what they call “a multi-mechanistic, targeted treatment.”

They will use the patient’s own immune cells and, in the lab, combine them with the OV. The cell/virus combination will then be administered back to the patient. The job of the CIK cells is to carry the virus to the tumors. The virus is designed to specifically attack and kill tumors and stimulate the patient’s immune system to attack the tumor cells. The goal is to eradicate the primary tumor and prevent relapse and recurrence.

“With the intent to develop this treatment for chemotherapy-resistant or refractory solid tumors—including colorectal cancer, triple negative breast cancer, ovarian cancer, gastric cancer, hepatocellular carcinoma, and osteosarcoma—it addresses a significant unmet medical need in fatal conditions for which there are limited treatment options,” says Dr. Maria T. Millan, President and CEO of CIRM.  

The CIRM Board also approved more than $18 million in funding four projects under the Translation Projects program. The goal of this program is to support promising regenerative medicine (stem cell-based or gene therapy) projects that accelerate completion of translational stage activities necessary for advancement to clinical study or broad end use.

The awards went to:

ApplicationTitleInstitutionAward Amount
TRAN1-133442Optogenetic therapy for treating retinitis pigmentosa and
other inherited retinal diseases  		  Paul Bresge Ray Therapeutics Inc.  $3,999,553  
TRAN3-13332Living Synthetic Vascular Grafts with Renewable Endothelium    Aijun Wang UC Davis  $3,112,567    
TRAN1-13370Next generation affinity-tuned CAR for prostate cancer    Preet Chaudhary University of Southern California  $5,805,144  
TRAN1-3345Autologous MPO Knock-Out Hematopoietic Stem and
Progenitor Cells for Pulmonary Arterial Hypertension  		  Don Kohn UC Los Angeles  $5,207,434  

Meet the people who are changing the future

/ Kevin McCormack / 2 Comments
Kristin MacDonald

Every so often you hear a story and your first reaction is “oh, I have to share this with someone, anyone, everyone.” That’s what happened to me the other day.

I was talking with Kristin MacDonald, an amazing woman, a fierce patient advocate and someone who took part in a CIRM-funded clinical trial to treat retinitis pigmentosa (RP). The disease had destroyed Kristin’s vision and she was hoping the therapy, pioneered by jCyte, would help her. Kristin, being a bit of a pioneer herself, was the first person to test the therapy in the U.S.

Anyway, Kristin was doing a Zoom presentation and wanted to look her best so she asked a friend to come over and do her hair and makeup. The woman she asked, was Rosie Barrero, another patient in that RP clinical trial. Not so very long ago Rosie was legally blind. Now, here she was helping do her friend’s hair and makeup. And doing it beautifully too.

That’s when you know the treatment works. At least for Rosie.

There are many other stories to be heard – from patients and patient advocates, from researchers who develop therapies to the doctors who deliver them. – at our CIRM 2020 Grantee Meeting on next Monday September 14th Tuesday & September 15th.

It’s two full days of presentations and discussions on everything from heart disease and cancer, to COVID-19, Alzheimer’s, Parkinson’s and spina bifida. Here’s a link to the Eventbrite page where you can find out more about the event and also register to be part of it.

Like pretty much everything these days it’s a virtual event so you’ll be able to join in from the comfort of your kitchen, living room, even the backyard.

And it’s free!

You can join us for all two days or just one session on one day. The choice is yours. And feel free to tell your friends or anyone else you think might be interested.

We hope to see you there.

Stem Cell All-Stars, All For You

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Dr. Larry Goldstein, UC San Diego

It’s not often you get a chance to hear some of the brightest minds around talk about their stem cell research and what it could mean for you, me and everyone else. That’s why we’re delighted to be bringing some of the sharpest tools in the stem cell shed together in one – virtual – place for our CIRM 2020 Grantee Meeting.

The event is Monday September 14th and Tuesday September 15th. It’s open to anyone who wants to attend and, of course, it’s all being held online so you can watch from the comfort of your own living room, or garden, or wherever you like. And, of course, it’s free.

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Dr. Daniela Bota, UC Irvine

The list of speakers is a Who’s Who of researchers that CIRM has funded and who also happen to be among the leaders in the field. Not surprising as California is a global center for regenerative medicine. And you will of course be able to post questions for them to answer.

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Dr. Deepak Srivastava, Gladstone Institutes

The key speakers include:

Larry Goldstein: the founder and director of the UCSD Stem Cell Program talking about Alzheimer’s research

Irv Weissman: Stanford University talking about anti-cancer therapies

Daniela Bota: UC Irvine talking about COVID-19 research

Deepak Srivastava: Gladsone Institutes, talking about heart stem cells

Other topics include the latest stem cell approaches to COVID-19, spinal cord injury, blindness, Parkinson’s disease, immune disorders, spina bifida and other pediatric disorders.

You can choose one topic or come both days for all the sessions. To see the agenda for each day click here. Just one side note, this is still a work in progress so some of the sessions have not been finalized yet.

And when you are ready to register go to our Eventbrite page. It’s simple, it’s fast and it will guarantee you’ll be able to be part of this event.

We look forward to seeing you there.

Perseverance: from theory to therapy. Our story over the last year – and a half

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Some of the stars of our Annual Report

It’s been a long time coming. Eighteen months to be precise. Which is a peculiarly long time for an Annual Report. The world is certainly a very different place today than when we started, and yet our core mission hasn’t changed at all, except to spring into action to make our own contribution to fighting the coronavirus.

This latest CIRM Annual Reportcovers 2019 through June 30, 2020. Why? Well, as you probably know we are running out of money and could be funding our last new awards by the end of this year. So, we wanted to produce as complete a picture of our achievements as we could – keeping in mind that we might not be around to produce a report next year.

Dr. Catriona Jamieson, UC San Diego physician and researcher

It’s a pretty jam-packed report. It covers everything from the 14 new clinical trials we have funded this year, including three specifically focused on COVID-19. It looks at the extraordinary researchers that we fund and the progress they have made, and the billions of additional dollars our funding has helped leverage for California. But at the heart of it, and at the heart of everything we do, are the patients. They’re the reason we are here. They are the reason we do what we do.

Byron Jenkins, former Naval fighter pilot who battled back from his own fight with multiple myeloma

There are stories of people like Byron Jenkins who almost died from multiple myeloma but is now back leading a full, active life with his family thanks to a CIRM-funded therapy with Poseida. There is Jordan Janz, a young man who once depended on taking 56 pills a day to keep his rare disease, cystinosis, under control but is now hoping a stem cell therapy developed by Dr. Stephanie Cherqui and her team at UC San Diego will make that something of the past.

Jordan Janz and Dr. Stephanie Cherqui

These individuals are remarkable on so many levels, not the least because they were willing to be among the first people ever to try these therapies. They are pioneers in every sense of the word.

Sneha Santosh, former CIRM Bridges student and now a researcher with Novo Nordisk

There is a lot of information in the report, charting the work we have done over the last 18 months. But it’s also a celebration of everyone who made it possible, and our way of saying thank you to the people of California who gave us this incredible honor and opportunity to do this work.

We hope you enjoy it.

CIRM invests in stem cell clinical trial targeting lung cancer and promising research into osteoporosis and incontinence

/ Kevin McCormack / 1 Comment

Lung cancer

Lung cancer: Photo courtesy Verywell

The five-year survival rate for people diagnosed with the most advanced stage of non-small cell lung cancer (NSCLC) is pretty grim, only between one and 10 percent. To address this devastating condition, the Board of the California Institute for Regenerative Medicine (CIRM) today voted to invest almost $12 million in a team from UCLA that is pioneering a combination therapy for NSCLC.

The team is using the patient’s own immune system where their dendritic cells – key cells in our immune system – are genetically modified to boost their ability to stimulate their native T cells – a type of white blood cell – to destroy cancer cells.  The investigators will combine this cell therapy with the FDA-approved therapy pembrolizumab (better known as Keytruda) a therapeutic that renders cancer cells more susceptible to clearance by the immune system.

“Lung cancer is a leading cause of cancer death for men and women, leading to 150,000 deaths each year and there is clearly a need for new and more effective treatments,” says Maria T. Millan, M.D., the President and CEO of CIRM. “We are pleased to support this program that is exploring a combination immunotherapy with gene modified cell and antibody for one of the most extreme forms of lung cancer.”

Translation Awards

The CIRM Board also approved investing $14.15 million in four projects under its Translation Research Program. The goal of these awards is to support promising stem cell research and help it move out of the laboratory and into clinical trials in people.

Researchers at Stanford were awarded almost $6 million to help develop a treatment for urinary incontinence (UI). Despite being one of the most common indications for surgery in women, one third of elderly women continue to suffer from debilitating urinary incontinence because they are not candidates for surgery or because surgery fails to address their condition.

The Stanford team is developing an approach using the patient’s own cells to create smooth muscle cells that can replace those lost in UI. If this approach is successful, it provides a proof of concept for replacement of smooth muscle cells that could potentially address other conditions in the urinary tract and in the digestive tract.

Max BioPharma Inc. was awarded almost $1.7 million to test a therapy that targets stem cells in the skeleton, creating new bone forming cells and blocking the destruction of bone cells caused by osteoporosis.

In its application the company stressed the benefit this could have for California’s diverse population stating: “Our program has the potential to have a significant positive impact on the lives of patients with osteoporosis, especially in California where its unique demographics make it particularly vulnerable. Latinos are 31% more likely to have osteoporosis than Caucasians, and California has the largest Latino population in the US, accounting for 39% of its population.”

Application Title Institution CIRM funding
TRAN1-10958 Autologous iPSC-derived smooth muscle cell therapy for treatment of urinary incontinence

 

  

Stanford University

  

$5,977,155

 
TRAN2-10990 Development of a noninvasive prenatal test for beta-hemoglobinopathies for earlier stem cell therapeutic interventions

 

  

Children’s Hospital Oakland Research Institute

  

$1,721,606

 
TRAN1-10937 Therapeutic development of an oxysterol with bone anabolic and anti-resorptive properties for intervention in osteoporosis  

MAX BioPharma Inc.

  

$1,689,855

 
TRAN1-10995 Morphological and functional integration of stem cell derived retina organoid sheets into degenerating retina models

 

  

UC Irvine

  

$4,769,039

 

Stem cell-based gut-on-a-chip: a new path to personalized medicine

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“Personalized medicine” is a trendy phrase these days, frequently used in TV ads for hospitals, newspaper articles about medicine’s future and even here in the Stem Cellar. The basic gist is that by analyzing a patient’s unique biology, a physician can use disease treatments that are most likely to work in that individual.

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Emulate’s Organ-on-a-Chip device.
Image: Emulate, Inc.

This concept is pretty straight-forward but it’s not always clear to me how it would play out as a routine clinical service for patients. A recent publication in Cellular and Molecular Gastroenterology and Hepatology by scientists at Cedars-Sinai and Emulate, Inc. paints a clearer picture. The report describes a device, Emulate’s Intestine-Chip, that aims to personalize drug treatments for people suffering from gastrointestinal diseases like inflammatory bowel disease and Chrohn’s disease.

Intestine-Chip combines the cutting-edge technologies of induced pluripotent stem cells (iPSCs) and microfluidic engineering. For the iPSC part of the equation, skin or blood samples are collected from a patient and reprogrammed into stem cells that can mature into almost any cell type in the body. Grown under the right conditions in a lab dish, the iPSCs self-organize into 3D intestinal organoids, structures made up of a few thousand cells with many of the hallmarks of a bona fide intestine.

RMI HOI

Miniature versions of a human intestinal lining, known as organoids, derived from induced pluripotent stem cells (iPSCs).
Image: Cedars-Sinai Board of Governors Regenerative Medicine Institute

These iPSC-derived organoids have been described in previous studies and represent a breakthrough for studying human intestinal diseases. Yet, they vary a lot in shape and size, making it difficult to capture consistent results. And because the intestinal organoids form into hollow tubes, it’s a challenge to get drugs inside the organoid, a necessary step to systematically test the effects of various drugs on the intestine.

The Intestine-Chip remedies these drawbacks. About the size of a double A battery, the Chip is made up of specialized plastic engineered with tiny tunnels, or micro-channels. The research team placed the iPSC-derived intestinal organoid cells into the micro-channels and showed that passing fluids with a defined set of ingredients through the device can prod the cells to mimic the human intestine.

RMI IntestinalChip

Cells of a human intestinal lining, after being placed in an Intestine-Chip, form intestinal folds as they do in the human body. Image: Cedars-Sinai Board of Governors Regenerative Medicine Institute

The Intestine-Chip not only looks like a human intestine but acts like one too. A protein known to be at high levels in inflammatory bowel disease was passed through the microchannel and the impact on the intestinal cells matched what is seen in patients. Clive Svendsen, Ph.D., a co-author on the study and director of the Cedars-Sinai Board of Governors Regenerative Medicine Institute, explained the exciting applications that the Intestine-Chip opens up for patients:

Svendsen

Clive Svendsen

“This pairing of biology and engineering allows us to re-create an intestinal lining that matches that of a patient with a specific intestinal disease—without performing invasive surgery to obtain a tissue sample,” he said in a press release. “We can produce an unlimited number of copies of this tissue and use them to evaluate potential therapies. This is an important advance in personalized medicine.”

Emulate’s sights are not just set on the human intestine but for the many other organs affected by disease. And because disease rarely impacts only one organ, a series of Organs-on-Chips for a particular patient could be examined together. Geraldine A. Hamilton, Ph.D., president and chief scientific officer of Emulate, Inc. summed up this point in a companion press release:

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Geraldine Hamilton

“By creating a personalized Patient-on-a-Chip, we can really begin to understand how diseases, medicines, chemicals and foods affect an individual’s health.”

 

 

CIRM interviews Lorenz Studer: 2017 recipient of the Ogawa-Yamanaka Stem Cell Prize [Video]

/ Todd Dubnicoff / 1 Comment

For eight long years, researchers who were trying to develop a stem cell-based therapy for Parkinson’s disease – an incurable movement disorder marked by uncontrollable shaking, body stiffness and difficulty walking – found themselves lost in the proverbial wilderness. In initial studies, rodent stem cells were successfully coaxed to specialize into dopamine-producing nerve cells, the type that are lost in Parkinson’s disease. And further animal studies showed these cells could treat Parkinson’s like symptoms when transplanted into the brain.

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Lorenz Studer, MD
Photo Credit: Sloan Kettering

But when identical recipes were used to make human stem cell-derived dopamine nerve cells the same animal experiments didn’t work. By examining the normal developmental biology of dopamine neurons much more closely, Lorenz Studer cracked the case in 2011. Now seven years later, Dr. Studer, director of the Center for Stem Cell Biology at the Memorial-Sloan Kettering Cancer Center, and his team are on the verge of beginning clinical trials to test their Parkinson’s cell therapy in patients

It’s for these bottleneck-busting contributions to the stem cell field that Dr. Studer was awarded the Gladstone Institutes’ 2017 Ogawa-Yamanaka Stem Cell Prize. Now in its third year, the prize was founded by philanthropists Hiro and Betty Ogawa along with  Shinya Yamanaka, Gladstone researcher and director of the Center for iPS Cell Research and Application at Kyoto University, and is meant to inspire and celebrate discoveries that build upon Yamanaka’s Nobel prize winning discovery of induced pluripotent stem cells (iPSCs).

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(L to R) Shinya Yamanaka, Andrew Ogawa, Deepak Srivastava present Lorenz Studer the 2017 Ogawa-Yamanaka Stem Cell Prize at Gladstone Institutes. Photo Credit: Todd Dubnicoff/CIRM

Studer was honored at the Gladstone in November and presented the Ogawa-Yamanka Stem Cell Prize Lecture. He was kind enough to sit down with me for a brief video interview (watch it below) a few minutes before he took the stage. He touched upon his Parkinson’s disease research as well as newer work related to hirschsprung disease, a dangerous intestinal disorder often diagnosed at birth that is caused by the loss of nerve cells in the gut. Using human embryonic stem cells and iPSCs derived from hirschsprung patients, Studer’s team has worked out the methods for making the gut nerve cells that are lost in the disease. This accomplishment has allowed his lab to better understand the disease and to make solid progress toward a stem cell-based therapy.

His groundbreaking work has also opened up the gates for other Parkinson’s researchers to make important insights in the field. In fact, CIRM is funding several interesting early stage projects aimed at moving therapy development forward:

We posted the 8-minute video with Dr. Studer today on our official YouTube channel, CIRM TV. You can watch the video here:

And for a more detailed description of Studer’s research, watch Gladstone’s webcast recording of his entire lecture:

Stem cell-derived mini-intestines reveal bacteria’s key role in building up a newborn’s gut

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The following factoid may induce an identity crisis for some people but it is true that our bodies carry more microbes than human cells. Some studies in 1970’s estimated the ratio at 10:1 though more recent calculations suggest we’re merely half microbe, half human.

Because microbes are much smaller than human cells they make up only about 1 or 2 percent of our total body mass. But that still amounts to trillions of micro-organisms, mostly bacteria, that live on and inside our bodies. The gut is one part of our body that is teeming with bacteria. Though that may sound gross, you’re very life depends on them. For example, these bacteria allow us to digest foods and take up nutrients that we wouldn’t be able to otherwise.

Intestines

E. coli bacteria, visible in this enhanced microscope image as tiny green rods, were injected into the center of a germ-free hollow ball of cells called a human intestinal organoid (inset image, top right). Within 48 hours, the cells formed much tighter connections with one another, visible as red in this image. Image courtesy of University of Michigan.

When we’re first born our intestines are germ-free but overtime helpful bacteria gain access to our gut and help it function, protecting it from infection by the continual exposure to harmful bacteria and viruses. New research out of the University of Michigan Medical School reported in eLife now shows that the initial bacterial infiltration is even more important than scientists previously thought. It appears to play a key role in stimulating human gut cells to shore up the intestine in preparation for the full wave of both micro-organisms and pathogens that are present throughout a person’s lifetime. The finding could help researchers discover methods to protect the gut from diseases like necrotizing enterocolitis, a rare but dangerous infection that strikes newborns.

To reach these conclusions, the research team grew human embryonic stem cells into miniature intestines in the lab. These so-called human intestinal organoids, or HIOs, are structures made up of a few thousand cells that form hollow tubes with many of the hallmarks of a bona fide intestine. The HIOs were first kept in a germ-free environment to mimic a newborn’s intestine. Then a form of helpful E. Coli bacteria, the same that’s often found in an infant’s diaper, was injected into the HIO and allowed to colonize the inside of the intestine.

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A single human intestinal organoid, or HIO — a hollow ball of cells grown from human embryonic stem cells and coaxed to become gut-lining cells. Scientists can use it to study basic gut development, and the effect of microbes on the cells, in a way that mimics the guts of newborn babies. Image courtesy of University of Michigan

The team observed several changes in gene activity shortly after the bacteria was introduced. Within a day or two, genes involved in producing proteins that fight off harmful microbes increased as well as genes that encode mucus production, a key part of protecting the cells that face the inside of the intestine. Other key features of a maturing intestine, such as tighter cell-to-cell connections and lowered oxygen levels were also stimulated by the presence of the bacteria. As co-senior author Vincent Young, M.D., Ph.D. explained in a press release, these results put the team in a position to uncover new insights about intestinal biology and disease:

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Vincent Young

“We have developed a system that faithfully reproduces the physiology of the immature human intestine, and will now make it possible to study a range of host-microbe interactions in the intestine to understand their functional role in health and disease.”

 

The particular mix of microbes found in one person versus another can differ a lot. And the impact of these differences on an individual’s health has been a trending topic in the media. Lead author David Hill, Ph.D., a postdoctoral fellow in the lab of Jason Spence, Ph.D., thinks that’s one specific research path that they aim to investigate with their HIO system:

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David Hill

“We hope to examine whether different bacteria produce different types of responses in the gut. This type of work might help to explain why different types of gut bacteria seem to be associated with positive or negative health outcomes.”

 

Stories that caught our eye last week: dying cells trigger stem cells, CRISPR videogames and an obesity-stem cell link

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A dying cell’s last breath triggers stem cell division. Most cells in your body are in a constant state of turnover. The cells of your lungs, for instance, replace themselves every 2 to 3 weeks and, believe it or not, you get a new intestine every 2 to 3 days. We can thank adult stem cells residing in these organs for producing the new replacement cells. But with this continual flux, how do the stem cells manage to generate just the right number of cells to maintain the same organ size? Just a slight imbalance would lead to either too few cells or too many which can lead to organ dysfunction and disease.

The intestine turnovers every five days. Stem cells (green) in the fruit fly intestine maintain organ size and structure. Image: Lucy Erin O’Brien/Stanford U.

Stanford University researchers published results on Friday in Nature that make inroads into explaining this fascinating, fundamental question about stem cell and developmental biology. Studying the cell turnover process of the intestine in fruit flies, the scientists discovered that, as if speaking its final words, a dying intestinal cell, or enterocyte, directly communicates with an intestinal stem cell to trigger it to divide and provide young, healthy enterocytes.

To reach this conclusion, the team first analyzed young enterocytes and showed that a protein these cells produce, called E-cadherin, blocks the release of a growth factor called EGF, a known stimulator of cell division. When young enterocytes became old and begin a process called programmed cell death, or apoptosis, the E-cadherin levels drop which removes the inhibition of EGF. As a result, a nearby stem cell now receives the EGF’s cell division signal, triggering it to divide and replace the dying cell. In her summary of this research in Stanford’s Scope blog, science writer Krista Conger explains how the dying cell’s signal to a stem cell ensures that there no net gain or loss of intestinal cells:

“The signal emitted by the dying cell travels only a short distance to activate only nearby stem cells. This prevents an across-the-board response by multiple stem cells that could result in an unwanted increase in the number of newly generated replacement cells.”

Because E-cadherin and the EGF receptor (EGFR) are each associated with certain cancers, senior author Lucy Erin O’Brien ponders the idea that her lab’s new findings may explain an underlying mechanism of tumor growth:

Lucy Erin O’Brien Image: Stanford U.

“Intriguingly, E-cadherin and EGFR are each individually implicated in particular cancers. Could they actually be cooperating to promote tumor development through some dysfunctional version of the normal renewal mechanism that we’ve uncovered?”

 

How a videogame could make gene editing safer (Kevin McCormack). The gene editing tool CRISPR has been getting a lot of attention this past year, and for good reason, it has the potential to eliminate genetic mutations that are responsible for some deadly diseases. But there are still many questions about the safety of CRISPR, such as how to control where it edits the genome and ensure it doesn’t cause unexpected problems.

Now a team at Stanford University is hoping to use a videogame to find answers to some of those questions. Here’s a video about their project:

The team is using the online game Eterna – which describes itself as “Empowering citizen scientists to invent medicine”. In the game, “players” can build RNA molecules that can then be used to turn on or off specific genes associated with specific diseases.

The Stanford team want “players” to design an RNA molecule that can be used as an On/Off switch for CRISPR. This would enable scientists to turn CRISPR on when they want it, but off when it is not needed.

In an article on the Stanford News website, team leader Howard Chang said this is a way to engage the wider scientific community in coming up with a solution:

Howard Chang
Photo: Stanford U.

“Great ideas can come from anywhere, so this is also an experiment in the democratization of science. A lot of people have hidden talents that they don’t even know about. This could be their calling. Maybe there’s somebody out there who is a security guard and a fantastic RNA biochemist, and they don’t even know it. The Eterna game is a powerful way to engage lots and lots of people. They’re not just passive users of information but actually involved in the process.”

They hope up to 100,000 people will play the game and help find a solution.

Altered stem cell gene activity partly to blame for obesity. People who are obese are often ridiculed for their weight problems because their condition is chalked up to a lack of discipline or self-control. But there are underlying biological processes that play a key role in controlling body weight which are independent of someone’s personality. It’s known that so-called satiety hormones – which are responsible for giving us the sensation that we’re full from a meal – are reduced in obese individuals compared to those with a normal weight.

Stem cells may have helped Al Roker’s dramatic weight loss after bariatric surgery. Photo: alroker.com

Bariatric surgery, which reduces the size of the stomach, is a popular treatment option for obesity and can lead to remarkable weight loss. Al Roker, the weatherman for NBC’s Today Show is one example that comes to mind of a weight loss success story after having this procedure. It turns out that the weight loss is not just due to having a smaller stomach and in turn smaller meals, but researchers have shown that the surgery also restores the levels of satiety hormones. So post-surgery, those individuals get a more normal, “I’m full”, feedback from their brains after eating a meal.

A team of Swiss doctors wanted to understand why the satiety hormone levels return to normal after bariatric surgery and this week they reported their answer in Scientific Reports. They analyzed enteroendocrine cells – the cells that release satiety hormones into the bloodstream and to the brain in response to food that enters the stomach and intestines – in obese individuals before and after bariatric surgery as well as a group of people with normal weight. The results showed that obese individuals have fewer enteroendocrine cells compared with the normal weight group. Post-surgery, those cells return to normal levels.

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Cells which can release satiety hormones are marked in green. For obese patients (middle), the number of these cells is markedly lower than for lean people (top) and for overweight patients three months after surgery (bottom). Image: University of Basil.

A deeper examination of the cells from the obese study group revealed altered patterns of gene activity in stem cells that are responsible for generating the enteroendocrine cells. In the post-surgery group, the patterns of gene activity, as seen in the normal weight group, are re-established. As mentioned in a University of Basil press release, these results stress that obesity is more than just a problem of diet and life-style choices:

“There is no doubt that metabolic factors are playing an important part. The study shows that there are structural differences between lean and obese people, which can explain lack of satiation in the obese.”