Better, faster stem cell reprogramming

A group at the Harvard Stem Cell Institute led by Derrick Rossi has taken a big step toward a holy grail in stem cell science — reprogramming skin cells to resemble embryonic stem cells without viruses (Cell Stem Cell paper). The new technique uses transient RNA to reprogram the cells into what they are calling RiPS cells (for RNA induced Pluripotent Stem Cells)

Reprogrammed human iPS cells were first generated in 2007 by Shinya Yamanaka of the Gladstone Institutes and Kyoto University, but his approach involved using a virus to insert four genes permanently into the cells. A Harvard press release describes the problems with the initial approach:

First, the use of the integrating viruses raised the very real possibility that cancers might inadvertently be triggered; and second, inserting the genes into the genome could lead to changes that would alter the properties of the resulting iPS cells so that they would not be identical to human embryonic stem cells.

Since that first discovery, scientists around the globe and in California have been working toward techniques that avoid viruses and don’t permanently alter cell's DNA. (Here is a list of CIRM grants focused on new ways of generating iPS cells.) Rossi describes the benefits of his approach:

“Gene therapy trials unfortunately taught us the danger in leaving viruses in the genome as some patients developed cancers that were driven by the integrated viruses. So when one thinks about strategies for regenerative medicine, you need to envisage utilizing cells whose genome has not been breached. We believe that utilizing RNA to generate transplantable cells and tissues is a ideal solution because, to the best of our knowledge, RNA is completely non-integrative.”

What’s still unclear is how similar these iPS cells are to their embryonic counterparts. Several recent papers have found that iPS cells can differ significantly from embryonic stem cells in their ability to generate all tissues. (We have blog entries on those papers here, here and here.) 

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California stem cell scientists comment on the federal funding fracas

Yesterday's decision by a U.S. Appeals court to allow human embryonic stem cell research to move forward pending a full appeal (see Reuters story) marks a good time to look back at how this legal back and forth impacts the field.

In late August, after the initial injunction halting federal funding for human embryonic stem cell research, CIRM issued a survey to grantees, roughly a quarter of whom reported having NIH funding for their stem cell work (here's our blog entry about that survey). The following are some comments from survey respondants:

"Interestingly, the early days of molecular biology were also filled with similar religious protests suggesting that scientists were playing god, but those objections were eventually discarded. Since then molecular biology has been so fundamental to medical research that few would admit to ever opposing it. I wonder if many organizations that opponents hESC research were also against molecular biology."

"I believe that after about 50 years, physicians will recognize the CIRM program above all others as being singularly instrumental in redefining the methodology of treatments and cures."

"My laboratory does not currently work with hESC but it is a possible future direction. If NIH does not fund this type of work, I will abandon it as a future long term project."

"CIRM funding for basic research on hESC is now more important than ever. without this the years spent developing this knowhow will be wasted"

"This ruling is extremely shortsighted. It will not aid the development of adult stem cell therapies and research. It is detrimental to the entire field and will hinder the development of therapies. At present we cannot predict which stem cell approach will work for which disease. Research is needed to establish a comparison base."

"This illustrates the problem with legislating by executive order, rather than changing the legislation itself. What will stop a new administration from banning hESC research and then another one permitting it again? Financially unstable research environment made worse by yo-yo policy making."

"I am just devastated, yet trying to be creative and optimistic to generate new funds for my research program and the investigators I am training.

"This turn of event is a sad day for stem cell researchers in America in particular and for all scientists in general. It will delay our progress in stem cell research and ultimately it is the people who will suffer more."

"Ironically, I don't disagree with the "legal" decision; I think the judge read congresses directive right. The problem is in the narrow language of the law and in our (scientists) failure to correct the record: "no embryo's were harmed in the generation of these ES lines". Only medical waste blastocysts were harmed. Honestly, saving blastocysts is a non-issue for 90% of the population. We need Obama and congress to re-write the law to allow generation of new ES lines and research on ethically obtained ES lines."

"For the millionth time, I find myself being thankful for CIRM."

And to the question of what work won't occur due to the funding freeze. Note how many people have concerns about the legal wrangling slowing iPS and adult stem cell research:

"1. Learning which stem cell type works best for a particular disease.
2. Understanding early human development -- particularly how birth defects, congenital diseases (like autism, degenerative diseases), and cancers arise
3. Aspects of drug discovery
4. Improvements in iPS technology"

"Basic understanding of the behavior of human ES cells. Many of the current cell lines are not very useful so the ability to make new xeno-free human ES is crucial for future use in clinical trials."

"This ruling will significantly hamper the development of non embryo derived therapies as well as any cell replacment therapies that may require ES cells."

"The funding freeze will negatively impact not only the human embryonic stem cell research funding under new guidelines, but will also freeze many research projects that would be fundable under Bush, or even non-stem cell research which is meshed in the same grant with the stem cell research (see additional comments)"

"It is critical to compare hESCs with iPSCs and aNPC results, and to carefully characterize each. Otherwise, the work on iPSCs and aNPCs may be misleading and even wrong."

"Any new field or biomedical research having enormous potential (e.g. stem cell research) or acute challenges (e.g. HIV / AIDS) requires enormous investment to produce useful return. The sheer breadth and depth of research that is required to convert the potential of stem cell research into reality can only be facilitated by Federal funding. For this to be derailed, even temporarily, on a dubious legal basis that seeks to overturn a previous Presidential order does disservice to the millions of people living with injuries or disease states that could benefit from such research."

"Our project was to study the effects of the environmental chemical, BPA, on the early stages of human development, a huge public health issue."

"understanding ES biology; and especially understanding how to better develop iPS (in order to rely less on ES in the future)."

"All stem cell research will be hindered by banning research on ES cells. ES cells are the quintessential stem cell, the gold standard. We need to study ES cells in parallel with all other types of cells used in regenerative medicine, as they inform one another. Through studies of development (the specialization of embryonic cells) we will learn about regeneration. The two go hand in hand."

"Comparative studies between iPSCs and ESCs, which are still sorely needed to understand putative differences between these two sources of stem cells."

"To numerous to list all repercussions here, but simply being able to compare ES, to iPS to adult cells and understand what makes them different, what line is best suited for what translational problem is the first big problem that comes to mind. But also all the wasted talent and effort, all those could have beens that will never get started because the atmosphere is simply too toxic."

"We could not fully understand stem cell biology.
We could not fully characterize the iPS cells and other reprogramed stem cells because we will have good controls."

We have some information about the different types of stem cells and how the work is tied together in our Stem Cell Basics.

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Artist inspired by HIV/AIDS therapies

Miracle of Hope I, Dave Putnam

The promise of a cure for HIV/AIDS has inspired activists, researchers and now artists. The image shown here, by Woodside, CA artist Dave Putnam, was donated to Stanford’s Positive Care Clinic in Atherton, CA. It’s one of three 36” by 48” images making up a new triptych depicting Putnam’s interpretation of the body’s triumph over HIV.

Stanford’s Scope blog describes the images:

The acrylics, which hang in the hallway of the clinic, show a cell that is permeated by multiple black dots. These represent the invasion of the HIV protease enzyme, which is essential to survival of the virus. Blue dots on the canvas are used to capture the image of the fighters – the protease inhibitors that stop cell growth. Gradually, the blue dots spread and overtake the nasty enzyme. In the last painting, a bright yellow canvas shines through, as the enzyme is destroyed (though remnants of the virus remain, as current therapies never completely eradicate it).

If the two CIRM-funded HIV disease teams at UCLA and City of Hope are successful, the disease would most resemble the final, less dramatic image. Both teams are trying to replace the person’s HIV-infected bloodstream with a new blood system that is resistant to the virus. This link provides more information about stem cell approaches to treating HIV/AIDS.




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Update on stem cell treatments for spinal cord injury

A nod to Paul Knoepfler at UC Davis, who has posted a blog entry about the Geron trial for spinal cord injury. It provides a nice summary of the science behind the trial, and a reminder of why patients might be hard to recruit. He refers to Michael Martinez, a jockey who recently sustained a severe spinal cord injury, and who was rejected for participation in Geron’s trial developed from human embryonic stem cells. As Knoepfler points out:

An important element of this treatment, as highlighted by the recent case with Martinez, is that the injury has to be of a certain kind to be treatable using Geron's approach. If too severe, the animal models would suggest the treatment won't help. In addition, the treatment must be given with 1-2 weeks of the injury.

We recently released a video about stem cell therapies for spinal cord injury, featuring CIRM board member Oswald Steward who directs the Reeve-Irvine Research Center at UC Irvine. CIRM funds several spinal cord injury research projects at that center, including some with Hans Keirstead who first developed the therapy being tested by Geron.

While talking with Dr. Steward for that video he discussed hopes for a therapy that would be effective after that first 1-2 week window. His lab recently showed that in rodents, neurons could be nudged to regrow over the site of an older injury (here's the UCI press release). Another group at UC Irvine found that human neural stem cells restored some mobility to mice that were in the chronic stages of spinal cord injury (here's our blog entry on that work).

You can learn more about CIRM work toward a stem cell based therapy for spinal cord injury on our Spinal Cord Injury Stem Cell Fact Sheet.

Human embryonic stem cells give clues to Huntington's disease origins

Researchers in Australia studying human embryonic stem cells have found evidence of the always-lethal Huntington’s disease when the cells are just a few days old. The disease, caused by a mutation in a single gene, normally starts causing symptoms when people are in mid-life.

This research shows the value of being able to study how a disease progresses in a lab dish. It would normally not be possible extract brain cells from people and study them in a lab dish. But in this case the scientists started with IVF embryos that contained the Huntington’s disease mutation, given by people using IVF to screen for the mutation before implantation. The embryos would otherwise be destroyed. They could extract embryonic stem cells, and then planned to mature those cells into the types of neurons damaged in Huntington’s disease as a way of understanding how the disease forms.

What the group learned is that the first indication of a problem is visible within days, in the mitochondria that generate power for the cell. An ABC story quotes senior author Leon McQuade from the Macquarie University's Australian Proteome Analysis Facility (APAF) in Sydney as saying:

“Human embryonic stem cells provide us with a very good model for doing drug toxicology and efficacy testing - it's a model that we really haven't had before.”

The scientists can use these cells to screen for drugs that might one day treat the disease.

CIRM funds two research projects, both being carried out by University of California, Davis scientists, working toward new therapies for Huntington’s Disease (links to research projects available here). One is generating new stem cell lines that contain the disease-causing mutation, such as those used in the Australian study. The other is working toward a therapy involving implanting a form of tissue specific stem cell into people with Huntington’s disease.

Learn more about CIRM work towards a stem cell based therapy for Huntington's Disease on our Huntington's Disease Stem Cell Fact Sheet.

Here's more on Huntington's disease and the search for a cure:

The University of California enters stem cell funding battle

The University of California has now entered the stem cell funding legal fracas, filing a motion to participate in the pending lawsuit. In a statement, the UC Office of the President said they are the first institution to seek to intervene in the lawsuit:

The recent U.S. District Court preliminary injunction blocking federally funded human embryonic stem cell (hESC) research threatens ongoing potential life-saving research and undermines the time-honored system of peer-reviewed science.

CIRM funds stem cell research projects at all ten UC system campuses (you can look up those awards on our online funding chart). In their blog, Nature breaks down the impact of the funding battle on just two of the UC schools:

The University of California, Los Angeles receives a total of 16 NIH grants from nine different NIH institutes involving work on human embryonic stem cells; those grants are worth a total of $8.7 million and provide full-time support for 46.5 researchers and staff. The University of California, San Diego, meanwhile, receives 14 NIH grants from five NIH institutes for human embryonic stem cell work, worth $7 million and employing 17.17 researchers and staff.

CIRM grantee at UC San Francisco Arnold Kriegstein wrote a statement in support of the motion. Kriegstein is director of the Eli and Edythe Broad Center for Regeneration Medicine and Stem Cell Research at UC San Francisco. In his statement, he says that although much of the human embryonic stem cell research taking place in California is funded by CIRM, the injunction has an impact that is disproportionate to the amount of funding received.

"The preliminary injunction has an impact on dozens of researchers and students, affecting programs across the UC campuses and across departments... Any loss of funding for the federal [human embryonic stem cell] projects will result in a loss of hours for these employees."

Kriegstein specifically cites a training program that includes 88 PhD and MD students being trained at UCSF, and which has had its funding discontinued due to the preliminary injnuction issued Aug. 23.

The court has ordered both the plaintiffs and defendants in the case to file a response to the UC motion by Thursday, September 23.

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The fate of embryonic stem cell research funding is in the hands of...

Thanks to UC Davis stem cell scientist and CIRM grantee Paul Knoepfler for ferreting out the three judges who will preside over the September 27 D.C. Circuit Court hearing regarding the August 23 injunction on federal funding for human embryonic stem cell research.

In his blog entry, Knoepfler writes that of the three judges one is a Clinton appointee and two were appointed by Bush Jr.

After some speculation about the outcome of this hearing, Knoepfler goes on to say:

However, keep in mind, as far as I understand the process, even a longer-term stay will only allow ES cell research to proceed until Lamberth makes a final ruling in the case and as we've said before, be assured he will against ES cell research. The questions are when will he rule, what happens then, and will a law already have been passed making the whole thing moot?

Bills have been introduced in both the House and Senate that would secure the legality of federal funding for human embryonic stem cell research

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Legal wrangling slows Stanford researcher's quest for a cure

Joanna Wysocka/Stanford University

What does all the legal wrangling mean for stem cell scientists? Stanford published a profile of up-and-coming star Joanna Wysocka, who talks about her own NIH-funded research. Wysocka was awarded the Outstanding Young Investigator Award at the annual meeting of the International Society for Stem Cell Research in June and has both a SEED and a New Faculty award from CIRM. In her acceptance speech for the ISSCR award Wysocka credited her SEED award for pulling her into the field of stem cell research.

Amidst her other successes, Wysocka also received the highest of scores on an NIH grant proposal that would fund stem cell research with the promise to help children with a rare developmental disorder known as CHARGE syndrome, which leads to life-threatening complications.

That award is one of the ones that got held up in the Aug. 23 ruling that threw NIH funding of human embryonic stem cell research into a tailspin. The Stanford story says:

“I am currently funding this project largely from leftovers of my start-up funds and relatively unrestricted junior investigator awards, but we need more money to continue,” she said. While the latest ruling means that the NIH can fund grants like hers, there is uncertainty among researchers nationwide due to the unsettled state of the law.

As of September 9, the NIH can once again proceed with funding human embryonic stem cell grants, but that funding is far from settled. That uncertainty could lead to significant delays.

Although the NIH now can move forward on her grant, she’s not sure how fast it can act — and whether the next court ruling could deal another setback before that happens. She noted that the NIH committee that must give final approval for her funding met while Lamberth’s ruling was in effect, so it did not consider her grant. That committee meets only three times a year, she said, so now she may have to wait.

“The review process was disrupted — it’s not something that can change in a day,” she said. “I have no clue when my grant will get back on track.”

The stem cell researchers and people employed in their labs are disrupted by the legal back and forth, but what’s worse is the uncertainty for families of children with CHARGE syndrome who look to work like Wysocka’s with hope.

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Hope for CIRM leukemia disease team

The clock is ticking on the 14 CIRM Disease Team projects issued last October, which are working under a four-year deadline to hit the clinic. The $20 million acute myeloid leukemia project headed up by Irv Weissman of Stanford University just reported some promising progress.

Weissman and his team are developing a chemotherapy drug that binds to a protein found on leukemia stem cells, killing the cells. The protein, called CD47, is also found on other cancer stem cells.

The work, which was published in the Sept. 3 issue of Cell, was focused on non-Hodgkins lymphoma. The group gave mice with non-hodgkins lymphoma the molecule that blocks CD47 in addition to another antibody, and cured the disease in 60 percent of cases.

According to a Stanford press release:

The researchers point out that, although the CIRM grant focuses on investigating anti-CD47 therapies for acute myeloid leukemia, the drug development process will result in an antibody that could also be used for other cancers. They focused their preliminary investigations on non-Hodgkin’s lymphoma because they were curious as to how the anti-CD47 antibody would work with rituximab, which also binds to human lymphoma cells.

The release goes on to say that the researchers hope to try the therapy in other cancers:

The researchers are moving forward to conduct tests on other CD47-expressing cancer cells, which include acute leukemia, bladder and several other cancer stem cells. They speculate that they might see a similar synergistic effect between anti-CD47 and other cancer-specific monoclonal antibodies currently in clinical use. They are also moving ahead as quickly as possible to bring the anti-CD47 antibody treatment to trials in human patients.

Recently, CIRM disease teams targeting brain tumors (blogged about here) and HIV/AIDS (blogged about here) have also had some preliminary success.

You can learn more about the CIRM disease team program in our October press release.

If you aren’t familiar with cancer stem cells, here’s a video with Catriona Jameison, a cancer stem cell scientist at University of California, San Diego, talking about their role in cancer.



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Lawmakers look to legalize human embryonic stem cell research

For now, the NIH is again able to fund research projects using human embryonic stem cells. However, if there’s anything to be learned from the past few weeks, it’s that the funding is uncertain. The only way to ensure continuous support at the federal level would be legislation specifically legalizing research using those cells.

Reps Diana DeGette, D-Colo., and Mike Castle, R-Del, have introduced legislation to legalize research using human embryonic stem cells. In the senate, Sen. Arlen Specter, D-Penn, has introduced similar legislation as has Sen. Tom Harkin, D-Iowa. Harkin is holding a hearing on Thursday before the Appropriations subcommittee on health, which he heads.

According to a story in the Chicago Tribune:

"There is great uncertainty in the research community as to what will happen," Specter said, explaining the need to pass a law confirming the research.

He said the NIH has spent $546 million on embryonic stem cell research "and phenomenal progress has already been made."

The story goes on to question whether lawmakers have the time or political will to take on the controversial topic. Unless they do, funding for human embryonic stem cell research at the federal level will remain uncertain.

The New York Times quotes DeGette as saying:

“I’ve been inundated with calls from freshman and other vulnerable members saying it’s not only the right issue to work on, but will also be politically good for them.”

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The ups and downs of federal funding for stem cell research

They can’t fund stem cell research...
They can...
They can’t fund stem cell research...
They can..

For now. In the “He loves me; He loves me not” game of stem cell research funding, the current petal removed by the U.S. Court of Appeals puts funding for human embryonic stem cell research back within the pervue of the NIH. Today the court put a hold on Judge Royce Lamberth's ruling that effectively halted NIH funding of human embryonic stem cell research. Bloomberg wrote:

“The purpose of this administrative stay is to give the court sufficient opportunity to consider the merits of the emergency motion for stay and should not be construed in any way as a ruling on the merits of that motion,” the appeals court wrote in its decision.

So far, the timeline of NIH funding of human embryonic stem cell research looks like this:

2001: Then-president George Bush limits federal funding for embryonic stem cell research to a handful of existing stem cell lines.
2004: Californians support proposition 71, creating the California Institute for Regenerative Medicine to administer $3 billion in bonds to fund stem cell research (adult and embryonic) in California.
2009: President Obama lifted the Bush-era restrictions, directing the NIH to create guidelines for approving new embryonic stem cell lines into the pool of those that can be included in federally funded research.
August 23, 2010: Judge Royce Lamberth ruled federal funding of human embryonic stem cell research impermissible under current laws. He put an immediate injunction on all federal funding for such research. Much confusion and uncertainty amongst stem cell scientists ensued, as documented by CIRM grantee at UC Davis Paul Knoepfler on his blog.
August 31, 2010: The U.S. Government appealed the ruling, citing irreparable harm to researchers, taxpayers and scientific progress.
September 7, 2010: Judge Lamberth refused the federal government's request to stay the order.
September 9, 2010: The U.S. Court of Appeals put a hold on Judge Lamberth’s ruling, allowing the NIH to continue funding research involving human embryonic stem cells.

The latest ruling is good news, but there are still many petals to remove before we know whether the NIH can fund, or fund not. For those scientists who have NIH funding for human embryonic stem cell research or who have grants under review, they still live with uncertainty over whether they’ll be able to complete those projects (or find cures for those diseases they hope to treat).

Throughout this, CIRM continues to fund stem cell research (embryonic and adult) in California, accelerating the pace to new cures, creating jobs, and building California’s biotechnology leadership. But as CIRM grantees told us in a survey, they need NIH funds in addition to CIRM. In the survey, 76% of CIRM grantees who have NIH funding said the funding freeze would impact their ability to carry out research with adult, cancer, or iPS stem cells.  Only 5% of grantees -- with or without NIH funding -- said the ruling would make no difference to their overall research strategy.

This table provides links to all CIRM-funded grants involving human embryonic stem cells.

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iPS cells from women create model for muscular dystrophy, X-linked diseases

Reprogrammed skin cells showing inactivated X in red

CIRM grantees at the University of California, Los Angeles have uncovered a feature of reprogrammed iPS cells that make them uniquely excellent for understanding diseases that arise from mutations on the X chromosome.

First some background. Men inherit an X chromosome from their mother, which contains many thousands of genes, and a Y from the father, which does little except confer manhood. Women inherit one X chromosome from each parent. Those female cells overcome their genetic overabundance by shutting down, at random, one of the two X chromosomes, putting the cells at genetic par with male cells.

But the two aren’t really equal. If men inherit a mutation on an X chromosome, it is present in every cell of the body and can cause muscular dystrophy, Rett Syndrome, color-blindness and other disorders. Women who inherit a mutation on an X chromosome from one parent will only show that mutation in half their cells. The other half of the body's cells, with the non-mutated chromosome active, can generally compensate.

So what does this have to do with reprogrammed cells and disease modeling? It turns out that the process of reprogramming skin cells into embryonic-like induced pluripotent stem cells doesn’t overturn the inactivated X. Reprogramming cells from a woman’s skin sample will produce two distinct types of iPS cell lines; half with one X active, and half of with the other X active. If one of those two chromosomes carries a mutation, say, for muscular dystrophy, some of those iPS lines will also display that mutation.

In a press release from UCLA, senior author Kathrin Plath said:

“This non-random pattern of X chromosome inactivation found in iPS cell lines has critical implications for clinical applications and disease modeling and could be exploited for a unique form of gene therapy for X-linked diseases.”

In a publication in Cell Stem Cell, Plath and her colleagues report that they created iPS cell lines from a woman who had inherited one X chromosome carrying a mutation that can cause muscular dystrophy. The other X chromosome had a normal copy of the gene. Scientists can now mature both groups of cells into skeletal muscle and compare the resulting tissue as a way of understanding—and perhaps one day treating—the devastating disease.

Cell Stem Cell: September 3, 2010
CIRM funding: Sean Sherman (TG2-01169), Kathrin Plath (RN1-00564), William Lowry (RS1-00259), Jerome Zack. (RL1-00681)