CRISPR-Cas9

How mRNA and CRISPR-Cas9 could treat muscle atrophy

/ Esteban Cortez / 1 Comment

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Researchers use mRNA to introduce the gene editor CRISPR-Cas9 into human muscle stem cells. These cells fused into multinucleated myotubes following mRNA-mediated CRISPR-Cas9 gene editing. A myosin heavy chain is seen in green and the nuclei in blue. Photo: Spuler Lab

A team of researchers from Experimental and Clinical Research Center (ECRC) has introduced the gene editor CRISPR-Cas9 into human muscle stem cells for the first time using messenger RNA (mRNA), potentially discovering a method suitable for therapeutic applications. 

The researchers are aiming to discover if this tool can repair mutations that lead to muscle atrophy in humans, and they are one step closer after finding that the method worked in mice suffering from the condition. But the method had a catch, ECRC researcher Helena Escobar says.  

“We introduced the genetic instructions for the gene editor into the stem cells using plasmids – which are circular, double-stranded DNA molecules derived from bacteria.” But plasmids could unintentionally integrate into the genome of human cells, which is also double stranded, and then lead to undesirable effects that are difficult to assess. “That made this method unsuitable for treating patients,” Escobar says.   

Getting mRNA Into Stem Cells

So the team set out to find a better alternative. They found it in the form of mRNA, a single-stranded RNA molecule that recently gained acclaim as a key component of two Covid-19 vaccines. 

To get the mRNA into the stem cells, the researchers used a process called electroporation, which temporarily makes cell membranes more permeable to larger molecules. “With the help of mRNA containing the genetic information for a green fluorescent dye, we first demonstrated that the mRNA molecules entered almost all the stem cells,” explains Christian Stadelmann, a doctoral student at ECRC.  

In the next step, the team used a deliberately altered molecule on the surface of human muscle stem cells to show that the method can be used to correct gene defects in a targeted manner.   

Paving the Way for a Clinical Trial 

Finally, the team tried out a tool similar to the CRISPR-Cas9 gene editor that does not cut the DNA, but only tweaks it at one spot with accuracy. In petri dish experiments, Stadelmann and his team were able to show that the corrected muscle stem cells are just as capable as healthy cells of fusing with each other and forming young muscle fibers. 

Their latest paper, which is appearing in the journal Molecular Therapy Nucleic Acids, paves the way for a clinical trial for patients with hereditary muscle atrophy. The team expects to enroll five to seven patients toward the end of the year. 

“Of course we cannot expect miracles,” says Simone Spuler, head of the Myology Lab at ECRC. “Sufferers who are in wheelchairs won’t just get up and start walking after the therapy. But for many patients, it is already a big step forward when a small muscle that is important for grasping or swallowing functions better again.” 

Read the source article here.

Tiny tools for the smallest of tasks, editing genes

/ Kevin McCormack / Leave a comment

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Developing new tools to edit genes

Having the right tools to do a job is important. Try using a large screwdriver to tighten the screws on your glasses and you quickly appreciate that it’s not just the type of tool that’s important, it’s also the size. The same theory applies to gene editing. And now researchers at Stanford have developed a tool that can take on even the tiniest of jobs.

The tool involves the use of CRISPR. You may well have heard about CRISPR. The magazine New Scientist described it this way: “CRISPR is a technology that can be used to edit genes and, as such, will likely change the world.” For example, CIRM is funding research using CRISPR to help children born with severe combined immunodeficiency, a rare, fatal immune disorder.  

There’s just one problem. Right now, CRISPR is usually twinned with a protein called Cas9. Together they are used to remove unwanted genes and insert a corrected copy of the bad gene. However, that CRISPR-Cas9 combination is often too big to fit into all our cells. That may seem hard to understand for folks like me with a limited science background, but trust the scientists, they aren’t making this stuff up.

To address that problem, Dr. Stanley Qi and his team at Stanford created an even smaller version, one they call CasMINI, to enable them to go where Cas9 can’t go. In an article on Fierce Biotech, Dr. Qi said this mini version has some big benefits: “If people sometimes think of Cas9 as molecular scissors, here we created a Swiss knife containing multiple functions. It is not a big one, but a miniature one that is highly portable for easy use.”

How much smaller is the miniature version compared to the standard Cas9? About half the size, 529 amino acids, compared to Cas9’s 1,368 amino acids.”

The team conclude their study in the journal Molecular Cell saying this could have widespread implications for the field: “This provides a new method to engineer compact and efficient CRISPR-Cas effectors that can be useful for broad genome engineering applications, including gene regulation, gene editing, base editing, epigenome editing, and chromatin imaging.”

Board Funds Fifteen Bridges to Stem Cell Research and Therapy Programs Across California and New Sickle Cell Disease Trial

/ Yimy Villa / 2 Comments

Yesterday the governing Board of the California Institute for Regenerative Medicine (CIRM) awarded $8.39 million to the University of California, San Francisco (UCSF) to fund a clinical trial for sickle cell disease (SCD).  An additional $51.08 million was awarded to fifteen community colleges and universities across California to fund undergraduate and master’s level programs that will help train the next generation of stem cell researchers. 

SCD is an inherited blood disorder caused by a single gene mutation that changes a single base in the B globin gene leading to the production of defective hemoglobin that polymerizes and damages red blood cells thus the “sickle” shaped red blood cells.  The damaged cells cause blood vessels to occlude/close up and that can lead to multiple organ damage as well as reduced quality of life and life expectancy. 

Mark Walters, M.D., and his team at UCSF Benioff Children’s Hospital Oakland will be conducting a clinical trial that uses CRISPR-Cas9 gene editing technology to correct the genetic mutation in the blood stem cells of patients with severe SCD.  The corrected blood stem cells will then be reintroduced back into patients with the goal of correcting the defective hemoglobin and thus producing functional, normal shaped red blood cells.

This clinical trial will be eligible for co-funding under the landmark agreement between CIRM and the National Heart, Lung, and Blood Institute (NHLBI) of the NIH.  The CIRM-NHLBI agreement is intended to co-fund cell and gene therapy programs under the NHLBI’s “Cure Sickle Cell” initiative.  The goal is to markedly accelerate the development of cell and gene therapies for SCD. CIRM has previously funded the preclinical development of this therapy through a Translational award as well as its IND-enabling studies through a Late Stage Preclinical award in partnership with NHLBI.

The CIRM Bridges to Stem Cell Research and Therapy program provides undergraduate and master’s students with the opportunity to take stem cell related courses and receive hands on experience and training in a stem cell research related laboratory at a university or biotechnology company.  Fifteen institutions received a total of $51.08 million to carry out these programs to train the next generation of scientists.

The awards are summarized in the table below.

ApplicationTitleInstitutionAward Amount
  EDUC2-12607Bridges to Stem Cell Research and Therapy at Pasadena City College  Pasadena City College$3,605,500
  EDUC2-12611CIRM Bridges to Stem Cell Research and Therapy Training Grant  CSU San Marcos$3,606,500
  EDUC2-12617Bridges to Stem Cell Research Internship Program  San Diego State University$3,606,500
EDUC2-12620CIRM Bridges 3.0  Humboldt State$3,605,495
  EDUC2-12638CIRM Regenerative Medicine and Stem Cell Research Biotechnology Training Program  CSU Long Beach$3,276,500
    EDUC2-12677Stem Cell Internships in Laboratory-based Learning (SCILL) continue to expand the scientific workforce for stem cells research and therapies.  San Jose State University$3,606,500
  EDUC2-12691Strengthening the Pipeline of Master’s-level Scientific and Laboratory Personnel in Stem Cell Research  CSU Sacramento$2,946,500
EDUC2-12693CIRM Bridges Science Master’s Program  San Francisco State University$3,606,500
      EDUC2-12695CIRM Graduate Student Training in Stem Cell Sciences in the Stem Cell Technology and Lab Management Emphasis of the MS Biotechnology Program  CSU Channel Islands$3,606,500
  EDUC2-12718CSUN CIRM Bridges 3.0 Stem Cell Research & Therapy Training Program  CSU Northridge$3,606,500
      EDUC2-12720Stem Cell Scholars: a workforce development pipeline, educating, training and engaging students from basic research to clinical translation.  CSU San Bernardino$3,606,500
  EDUC2-12726Training Master’s Students to Advance the Regenerative Medicine Field  Cal Poly San Luis Obispo$3,276,500
  EDUC2-12730Building Career Pathways into Stem Cell Research and Therapy Development  City College of San Francisco$2,706,200
      EDUC2-12734Bridges to Stem Cell Research and Therapy: A Talent Development Program for Training Diverse Undergraduates for Careers in Regenerative Medicine  CSU Fullerton$3,606,500
  EDUC2-12738CIRM Bridges to Stem Cell Research and Therapy  Berkeley City College  $2,806,896

“We are pleased to fund a promising trial for sickle cell disease that uses the Nobel Prize winning gene editing technology CRISPR-Cas9,” says Maria T. Millan, M.D., President and CEO of CIRM.  “This clinical trial is a testament to how the CIRM model supports promising early-stage research, accelerates it through translational development, and advances it into the clinics. As the field advances, we must also meet the demand for promising young scientists.  The CIRM Bridges programs across the state of California will provide students with the tools and resources to begin their careers in regenerative medicine.”

Three UC’s Join Forces to Launch CRISPR Clinical Trial Targeting Sickle Cell Disease

/ Kevin McCormack / Leave a comment
Sickle shaped red blood cells

The University of California, San Francisco (UCSF), in collaboration with UC Berkeley (UCB) and UC Los Angeles (UCLA), have been given permission by the US Food and Drug Administration (FDA) to launch a first-in-human clinical trial using CRISPR technology as a gene-editing technique to cure Sickle Cell Disease.

This research has been funded by CIRM from the early stages and, in a co-funding partnership with theNational Heart, Lung, and Blood Institute under the Cure Sickle Cell initiatve, CIRM supported the work that allowed this program to gain FDA permission to proceed into clinical trials.    

Sickle Cell Disease is a blood disorder that affects around 100,000 people, mostly Black and Latinx people in the US. It is caused by a single genetic mutation that results in the production of “sickle” shaped red blood cells. Normal red blood cells are round and smooth and flow easily through blood vessels. But the sickle-shaped ones are rigid and brittle and clump together, clogging vessels and causing painful crisis episodes, recurrent hospitalization, multi-organ damage and mini-strokes.    

The three UC’s have combined their respective expertise to bring this program forward.

The CRISPR-Cas9 technology was developed by UC Berkeley’s Nobel laureate Jennifer Doudna, PhD. UCLA is a collaborating site, with expertise in genetic analysis and cell manufacturing and UCSF Benioff Children’s Hospital Oakland is the lead clinical center, leveraging its renowned expertise in cord blood and marrow transplantation and in gene therapy for sickle cell disease.

The approach involves retrieving blood stem cells from the patient and, using a technique involving electrical pulses, these cells are treated to correct the mutation using CRISPR technology. The corrected cells will then be transplanted back into the patient.

Dr. Mark Walters

In a news release, UCSF’s Dr. Mark Walters, the principal investigator of the project, says using this new gene-editing approach could be a game-changer. “This therapy has the potential to transform sickle cell disease care by producing an accessible, curative treatment that is safer than the current therapy of stem cell transplant from a healthy bone marrow donor. If this is successfully applied in young patients, it has the potential to prevent irreversible complications of the disease. Based on our experience with bone marrow transplants, we predict that correcting 20% of the genes should be sufficient to out-compete the native sickle cells and have a strong clinical benefit.”

Dr. Maria T. Millan, President & CEO of CIRM, said this collaborative approach can be a model for tackling other diseases. “When we entered into our partnership with the NHLBI we hoped that combining our resources and expertise could accelerate the development of cell and gene therapies for SCD. And now to see these three UC institutions collaborating on bringing this therapy to patients is truly exciting and highlights how working together we can achieve far more than just operating individually.”

The 4-year study will include six adults and three adolescents with severe sickle cell disease. It is planned to begin this summer in Oakland and Los Angeles.

The three UCs combined to produce a video to accompany news about the trial. Here it is:

CIRM-Funded Project Targeting Sickle Cell Disease Gets Green Light for Clinical Trial

/ Kevin McCormack / Leave a comment
Dr. Matthew Porteus

The US Food and Drug Administration (FDA) has granted Investigational New Drug (IND) permission enabling Graphite Bio to test the investigational, potentially revolutionary gene editing therapy GPH101 developed under the supervision of Matthew Porteus, MD, PhD, in a clinical trial for people with sickle cell disease (SCD).

The California Institute for Regenerative Medicine (CIRM) has been supporting this project with a $5.2 million grant, enabling Dr. Porteus and his team at the Institute of Stem Cell Biology and Regenerative Medicine at Stanford University to conduct the preclinical manufacturing and safety studies required by the FDA.

“We congratulate the Graphite Bio team for obtaining the IND, a critical step in bringing the GPH101 gene therapy forward for Sickle Cell Disease,” says Dr. Maria T. Millan, CIRM’s President & CEO. “CIRM is committed to the national Cure Sickle Cell initiative and are delighted that this technology, the product of CIRM funded research conducted by Dr. Porteus at Stanford, is progressing to the next stage of development”

Sickle cell disease is caused by a genetic mutation that turns normally smooth, round red blood cells into rigid, sickle shaped cells. Those cells clump together, clogging up blood vessels, causing intense pain, damaging organs and increasing the risk of strokes and premature death. There are treatments that help control the damage, but the only cure is a bone marrow stem cell transplant, which can only happen if the patient has a stem cell donor (usually a close relative) who has matching bone marrow.  

The investigational therapy GPH101 harnesses the power of CRISPR and natural DNA repair mechanisms to cut out the single mutation in the sickle globin gene and paste in the correct “code.” Correction of this mutation would reverse the defect and result in healthy non-sickling red blood cells.  

CEDAR, a Phase 1/2, multi-center, open-label clinical study is designed to evaluate the safety, preliminary efficacy and pharmacodynamics of GPH101 in adult and adolescent patients with severe SCD.

For patient advocate Nancy Rene, the news is personal: “It’s always exciting to hear about the progress being made in sickle cell research.  If successful it will mean that my grandson, and especially other young adults, can look forward to a life free of pain and organ damage.  They can actually begin to plan their lives, thinking about careers and families. I want to thank Dr. Porteus and all of the scientists who are working so hard for people with sickle cell disease. This is wonderful news.”

CIRM has funded four clinical trials for Sickle Cell Disease using different approaches and has a unique partnership with the National Heart, Lung and Blood Institutes under the NIH “Cure Sickle Cell” initiative.

CIRM progression award to support research towards immunodeficiency

/ Yimy Villa / 1 Comment
Dr. Caroline Kuo, a member of the Eli and Edythe Broad Center of Regenerative Medicine and Stem Cell Research at UCLA

In 2017, CIRM funded a discovery or early stage research project for Dr. Caroline Kuo at UCLA for a hereditary immune disorder known as X-Linked Hyper IgM Syndrome. The work has gone so well that Dr. Kuo and her team are now preparing the pre-clinical work needed to launch a clinical trial.

Thanks to the success of her discovery stage project (these are intended to promote promising new technologies that could be translated to enable broad use and improve patient care), Dr. Kuo received a CIRM progression award to launch a new project for DOCK8 deficiency, a different type of Hyper IgE Syndrome. This new project will compare two gene therapy techniques as potential treatments for DOCK8 deficiency.

Hyper IgM Syndrome is a genetic disorder that occurs when there are abnormal levels of different types of antibodies (Ig) in the body.  Antibodies combat infections by attaching to germs and other foreign substances, marking them for destruction.  In infants with Hyper IgM Syndrome , there are normal or high levels of antibody IgM but low levels of antibodies IgG, IgA, and IgE.  The low level of these antibodies make it difficult to fight off infection, resulting in frequent pneumonia, sinus infections, ear infections, and parasitic infections.  Additionally, these infants have an increased risk of cancerous growths.

While X-Linked Hyper IgM Syndrome is caused by a mutation in the X gene, DOCK8 deficiency is caused by a mutation in the DOCK8 gene. More than 95% of patients with DOCK8 deficiency die by age 40.

To determine the best approach to treat DOCK8 deficiency, Dr. Kuo will compare a traditional gene therapy method with another gene therapy approach that uses CRISPR-Cas9, which work like scissors and can be directed to cut DNA at specific sites to disable, repair, or make other alterations to genes.

In a press release from UCLA, Dr. Kuo describes what inspired her to pursue this research.

“I wanted to research new treatment options for DOCK8 deficiency because I see how debilitating it can be for my patients. It’s already bad enough that my patients feel sick but then add to that visible skin infections on their hands and face that are difficult to treat, I think that’s the hardest part for a lot of the children I see. The prospect of developing a curative therapy for patients definitely brings a lot more meaning to the work.”

Stanford scientist uses CRISPR-Cas9 and stem cells to develop potential “bubble baby” therapy

/ Yimy Villa / 1 Comment
Dr. Matthew Porteus, professor of pediatrics at Stanford University.
Photo courtesy of Stanford Medicine.

Our immune system is an important and essential part of everyday life. It is crucial for fighting off colds and, with the help of vaccinations, gives us immunity to potentially lethal diseases. Unfortunately, for some infants, this innate bodily defense mechanism is not present or is severely lacking in function.

This condition is known as severe combined immunodeficiency (SCID), commonly nicknamed “bubble baby” disease because of the sterile plastic bubble these infants used to be placed in to prevent exposure to bacteria, viruses, and fungi that can cause infection. There are several forms of SCID, one of which involves a single genetic mutation on the X chromosome and is known as SCID-X1

Many infants with SCID-X1 develop chronic diarrhea, a fungal infection called thrush, and skin rashes. Additionally, these infants grow slowly in comparison to other children. Without treatment, many infants with SCID-X1 do not live beyond infancy.

SCID-X1 occurs almost predominantly in males since they only carry one X chromosome, with at least 1 in 50,000 baby boys born with this condition. Since females carry two X chromosomes, one inherited from each parent, they are unlikely to inherit two X chromosomes with the mutation present since it would require the father to have SCID-X1.

What if there was a way to address this condition by correcting the single gene mutation? Dr. Matthew Porteus at Stanford University is leading a study that has developed an approach to treat SCID-X1 that utilizes this concept.

By using CRISPR-Cas9 technology, which we have discussed in detail in a previous blog post, it is possible to delete a problematic gene and insert a corrected gene. Dr. Porteus and his team are using CRISPR-Cas9 to edit blood stem cells, which give rise to immune cells, which are the foundation of the body’s defense mechanism. In a study published in Nature, Dr. Porteus and his team have demonstrated proof of concept of this approach in an animal model.

The Stanford team was able to take blood stem cells from six infants with SCID-X1 and corrected them with CRISPR-Cas9. These corrected stem cells were then introduced into mice modeled to have SCID-X1. It was found that these mice were not only able to make immune cells, but many of the edited stem cells maintained their ability to continuously create new blood cells.

In a press release, Dr. Mara Pavel-Dinu, a member of the research team, said:

“To our knowledge, it’s the first time that human SCID-X1 cells edited with CRISPR-Cas9 have been successfully used to make human immune cells in an animal model.”

CIRM has previously awarded Dr. Porteus with a preclinical development award aimed at developing gene correction therapy for blood stem cells for SCID-X1. In addition to this, CIRM has funded two other projects conducted by Dr. Porteus related to CRISPR-Cas9. One of these projects used CRISPR-Cas 9 to develop a treatment for chronic sinusitis due to cystic fibrosis and the second project used the technology to develop an approach for treating sickle cell disease.

CIRM has also funded four clinical trials related to SCID. Two of these trials are related to SCID-X1, one being conducted at St. Jude Children’s Research Hospital and the other at Stanford University. The third trial is related to a different form of SCID known as ADA-SCID and is being conducted at UCLA in partnership with Orchard Therapeutics. Finally, the last of the four trials is related to an additional form of SCID known as ART-SCID and is being conducted at UCSF.

CRISPR-Cas9 101: an overview and the role it plays in developing therapies

/ Yimy Villa / 3 Comments
Illustration courtesy of TED website

There has been a lot of conversation surrounding CRISPR-Cas9 in these recent months as well as many sensational news stories. Some of these stories highlight the promise this technology holds, while others emphasize a word of caution. But what exactly does this technology do and how does it work? Here is a breakdown that will help you better understand.

To start off, CRISPR is a naturally occurring process found in bacteria used as an immune system to defend against viruses. CRISPR simply put, are strands of DNA segments that contain repeating patterns. There are “scissor like” CRISPR proteins that have the ability to cut DNA segments. When a copy of a virus enters the bacteria, these “scissor like” proteins cut a segment of DNA from the virus and insert it into CRISPR. A copy of the viral DNA is made and another “attack” protein known as Cas9 attaches to it. By binding to the viral copy, Cas9 is able to sense that virus. When the same virus tries to enter the bacteria, Cas9 is able to seek and destroy it.

You can view a more detailed video explaining this concept below.

Many scientists analyzed this process in detail and it was eventually discovered that this CRISPR-Cas9 complex could be used to removed unwanted genes and insert a corrected copy, revolutionizing the way that we view the approach towards treating a wide variety of genetic diseases.

In fact, researchers at the Dana-Farber/Boston Children’s Cancer and Blood Disorders Center and the University of Massachusetts Medical School have developed a strategy using this complex to treat two inherited, lethal blood disorders, sickle cell disease (SCD) and beta thalassemia. Both of these diseases involve a mutation that effects production of red blood cells, which are produced by blood stem cells. In beta-thalassemia, the mutation prevent red blood cells from being able to carry enough oxygen, leading to anemia. In SCD, the mutations cause red blood cells to take on a “sickle” shape which can block blood vessels.

By using CRISPR-Cas9 to insert a corrected copy of the gene into a patient’s own blood stem cells, this team demonstrated that functional red blood cells can then be produced. These results pay the way for other blood disorders as well.

In a press release , Dr. Daniel Bauer, an attending physician with Dana-Farber and a senior author on both of these studies stated that,

“Combining gene editing with an autologous stem-cell transplant could be a therapy for sickle-cell disease, beta-thalassemia and other blood disorders.”

In a separate study, scientists at University of Massachusetts Medical School have developed a strategy that could be used to treat genetic disorders associated with unintentional repeats or copies of small DNA segments. These problematic small segments of DNA are called microduplications and cause as many as 143 different diseases, including limb-girdle muscular dystrophy, Hermansky-Pudlak syndrome, and Tay-Sachs.

Because these are issues caused by repeats or copies of small DNA segments, the CRISPR-Cas9 complex can be used to remove microduplications without having to insert any additional genetic material.

Dr. Scot A. Wolfe, a co-investigator of this study, stated that,

“It’s like hitting the reset button. We don’t have to add any corrective genetic material, instead the cell stitches the DNA back together minus the duplication. It’s a shortcut for gene correction with potential therapeutic appeal.”

Although there has been a lot progress made with this technology, there are still concerns that need to be addressed. An article in Science mentions how two studies have shown that CRISPR can still make unintended changes to DNA, which can be potentially dangerous. In the article, Dr. Jin-Soo Kim, a CRISPR researcher at Seoul National University is quoted as saying,

“It is now important to determine which component is responsible for the collateral mutations and how to reduce or avoid them.”

Overall, CRISPR-Cas9 has revolutionized the approach of precision medicine. A wide variety of diseases are caused by small, unexpected segments of DNA. By applying this approach found in bacteria to humans, we have uncovered a way to correct these segments at the microscopic level. However, there is still much that needs to be learned and perfected before it can be utilized in patients.

Midwest universities are making important tools to advance stem cell research

/ Pallavi Penumetcha / 1 Comment

580b4-ipscell

iPSCs are not just pretty, they’re also pretty remarkable

Two Midwest universities are making headlines for their contributions to stem cell research. Both are developing important tools to advance this field of study, but in two unique ways.

Scientists at the University of Michigan (UM), have compiled an impressive repository of disease-specific stem cell lines. Cell lines are crucial tools for scientists to study the mechanics of different diseases and allows them to do so without animal models. While animal models have important benefits, such as the ability to study a disease within the context of a living mammal, insights gained from such models can be difficult to translate to humans and many diseases do not even have good models to use.

The stem cell lines generated at the Reproductive Sciences Program at UM, are thanks to numerous individuals who donated extra embryos they did not use for in vitro fertilization (IVF). Researchers at UM then screened these embryos for abnormalities associated with different types of disease and generated some 36 different stem cell lines. These have been donated to the National Institute of Health’s (NIH) Human Embryonic Stem Cell Registry, and include cell lines for diseases such as cystic fibrosis, Huntington’s Disease and hemophilia.

Using one such cell line, Dr. Peter Todd at UM, found that the genetic abnormality associated with Fragile X Syndrome, a genetic mutation that results in developmental delays and learning disabilities, can be corrected by using a novel biological tool. Because Fragile X Syndrome does not have a good animal model, this stem cell line was critical for improving our understanding of this disease.

In the next state over, at the University of Wisconsin-Madison (UWM), researchers are doing similar work but using induced pluripotent stem cells (iPSCs) for their work.

The Human Stem Cell Gene Editing Service has proved to be an important resource in expediting research projects across campus. They use CRISPR-Cas9 technology (an efficient method to mutate or edit the DNA of any organism), to generate human stem cell lines that contain disease specific mutations. Researchers use these cell lines to determine how the mutation affects cells and/or how to correct the cellular abnormality the mutation causes. Unlike the work at UM, these stem cell lines are derived from iPSCs  which can be generated from easy to obtain human samples, such as skin cells.

The gene editing services at UWM have already proved to be so popular in their short existence that they are considering expanding to be able to accommodate off-campus requests. This highlights the extent to which both CRISPR technology and stem cell research are being used to answer important scientific questions to advance our understanding of disease.

CIRM also created an iPSC bank that researchers can use to study different diseases. The  Induced Pluripotent Stem Cell (iPSC) Repository is  the largest repository of its kind in the world and is used by researchers across the globe.

The iPSC Repository was created by CIRM to house a collection of stem cells from thousands of individuals, some healthy, but some with diseases such as heart, lung or liver disease, or disorders such as autism. The goal is for scientists to use these cells to better understand diseases and develop and test new therapies to combat them. This provides an unprecedented opportunity to study the cell types from patients that are affected in disease, but for which cells cannot otherwise be easily obtained in large quantities.

For the first time, scientists entirely reprogram human skin cells to iPSCs using CRISPR

/ Pallavi Penumetcha / Leave a comment

Picture1

CRISPR iPSC colony of human skin cells showing expression of SOX2 and TRA-1-60, markers of human embryonic pluripotent stem cells

Back in 2012, Shinya Yamanaka was awarded the Nobel Prize in Physiology or Medicine for his group’s identification of “Yamanaka Factors,” a group of genes that are capable of turning ordinary skin cells into induced pluripotentent stem cells (iPSCs) which have the ability to become any type of cell within the body. Discovery of iPSCs was, and has been, groundbreaking because it not only allows for unprecedented avenues to study human disease, but also has implications for using a patient’s own cells to treat a wide variety of diseases.

Recently, Timo Otonkoski’s group at the University of Helsinki along with Juha Kere’s group at the Karolinska Institutet and King’s College, London have found a way to program iPSCs from skin cells using CRISPR, a gene editing technology. Their approach allows for the induction, or turning on of iPSCs using the cells own DNA, instead of introducing the previously identified Yamanka Factors into cells of interest.

As detailed in their study, published in the journal Nature Communications, this is the first instance of mature human cells being completely reprogrammed into pluripotent cells using only CRISPR. Instead of using the canonical CRISPR system that allows the CAS9 protein (an enzyme that is able to cut DNA, thus rendering a gene of interest dysfunctional) to mutate any gene of interest, this group used a modified version of the CAS9 protein, which allows them to turn on or off the gene that CAS9 is targeted to.

The robustness of their approach lies in the researcher’s identification of a DNA sequence that is commonly found near genes involved in embryonic development. As CAS9 needs to be guided to genes of interest to do its job, identification of this common motif allows multiple genes associated with pluripotency to be activated in mature human skin cells, and greatly increased the efficiency and effectiveness of this approach.

In a press release, Dr. Otonkoski further highlights the novelty and viability of this approach:

“…Reprogramming based on activation of endogenous genes rather than overexpression of transgenes is…theoretically a more physiological way of controlling cell fate and may result in more normal cells…”