iPSC Repository

Stem Cell Tools: Helping Scientists Model Complex Diseases

/ Karen Ring / 1 Comment

This blog is part of the Month of CIRM series and the first of two blogs focused on how CIRM-funded infrastructure initiatives are developing useful tools to advance stem cell research. 

Human stem cells are powerful tools for studying human disease.  Animal models like mice have been and continue to be important for studying physiological systems, but they are still different than human systems.  Other types of human cells studied in the lab often are isolated from cancers or modified to multiply indefinitely.  However, the genetic DNA blueprint of these modified cells are irreparably altered from the normal tissues that they came from.

Human pluripotent stem cells are unique in that they can be grown in the lab and turned into any type of normal cell in the body.  Many scientists now believe that creating such stem cell lines from patients and developing ‘disease-in-a-dish’ models will provide important insights that will lead to treatments for the disorders from which they came.  Challenges still remain to develop these models to their fullest potential.  Because the genetics underlying human disease is complex, detailed genetic information about each stem cell line, as well as a large number of lines  to represent the genetic variability between patients will be needed to make progress.

To address this need, CIRM funded the creation of the world’s largest induced pluripotent stem cell bank, which we call the CIRM iPSC Repository.  iPSCs are similar to embryonic stem cells in that they can develop into any cell type found in the body, but they differ in how they are derived. Scientists can take human skin or blood cells and genetically reprogram them into iPSCs that have the same genetic makeup, including any disease-causing mutations, as the person from which the original cells were taken. Embryonic stem cells, on the other hand, are derived from left over embryos donated by couples undergoing in vitro fertilization (IVF) treatments.

The CIRM iPSC Repository was established to harness the power of iPSCs as tools for disease modeling and drug discovery. The Repository currently offers scientists around the world access to over 1500 high-quality iPSC lines covering diseases of the brain, heart, liver, lung, and eye, and the collection will eventually hold over 3000 lines.  All iPSC lines are linked to publicly-accessible demographic and clinical information.

Making the Cell Lines

Making the iPSC Repository was no easy task – it took a village of doctors, scientists, patients and healthy volunteers. First, clinicians across California collected blood and skin samples from over 2800 people including individuals with common diseases, rare diseases and healthy controls. CIRM then awarded a grant to Cellular Dynamics International to create iPSC lines from these donors, and a second grant to the Coriell Institute to store and distribute the lines to interested labs around the world. Creating such a large number of lines in a single concerted effort has been a challenging logistical feat that has taken almost five years and is projected to finish in early 2018.

Joachim Hallmayer

We spoke with one of the tissue collectors, a scientist named Dr. Joachim Hallmayer at Stanford University, about the effort it took to obtain tissue samples for the Repository. Hallmayer is a Professor of Psychiatry and Behavioral Sciences at Stanford who studies Autism Spectrum Disorder (ASD) in children. With funding from a CIRM Tissue Collection for Disease Modeling award, Hallmayer collected tissue samples from children with ASD and children with normal development. His efforts resulted in the 164 ASD and 134 control samples for the Repository.

Hallmayer emphasized that each sample donation required significant attention and education from the clinical staff to the donor.  Communicating with patients and walking them through the consent process for donating their tissue for this purpose is an extremely important issue that is often overlooked. “Conveying information about the tissue collection process to patients takes a lot of time. However, deconstructing the consent process is essential for patients to understand what they are donating and why,” explained Hallmayer.

Now that the ASD lines are available, Hallmayer and his colleague Dr. Ruth O’Hara are formulating a plan to model ASD in a dish by differentiating the iPSC lines into neurons affected by this disorder. Says O’Hara:

Ruth O’Hara

“While the examination of live tissue from other organ systems has become increasingly viable, examining live neurons from patients with brain disorders has simply not been possible. Using iPSC-derived neurons, for the first time we can study live nerve cells from actual patients and compare these cells to those from humans without the disorder.”

Using iPSCs to Model Psychiatric Disorders

Ultimately, the goal of iPSCs for modeling disease is to identify mechanisms and therapeutic targets for the disorders that they represent.  Studying a disease through a single iPSC line may not shed enough light on that disorder.  Just as people have diverse traits, the way that a disease can affect individuals is also diverse.  Studying large numbers of lines in a time and cost-efficient manner that represent these diverse traits, and the genetic causes that underlie them, can be a powerful method to understand and address diseases.

 To leverage the iPSC collection for this purpose, CIRM and a group of scientists at the Broad Institute’s Stanley Center for Psychiatric Research and Harvard University have entered into a collaboration to study psychiatric disorders such as ASD.  Because the donor samples were collected on the basis of clinical information, the genetic information about what caused their disease remains unknown.  Therefore, the Stanley Center will embark on whole genome sequencing (WGS) of hundreds of lines from the CIRM iPSC repository. Adding donor WGS sequence information to the CIRM repository will significantly increase its value, as scientists will be able to use DNA sequence information to select the ideal lines for disease modeling and therapeutic discovery efforts. The collaboration aims to identify the genes that shape neuronal phenotypes in iPSC-derived neurons from patients with psychiatric disorders.

“A central challenge today is to discover how inherited genetic variation gives rise to functional variation in the properties of neurons and other cells,” said Steven McCarroll, Director of Genetics at the Broad Institute’s Stanley Center for Psychiatric Research, and associate professor at Harvard Medical School’s Department of Genetics. “We hope with the analysis of cells from very large numbers of genetically diverse individuals will begin to address longstanding problems at the interface of human genetics and biology.”

iPSC derived neurons growing in a dish. (Image courtesy of Ralda Nehme, Research Scientist at the Broad Institute).

Such efforts require technologies such as Drop-seq, developed in the McCarroll lab, where genome-wide expression of thousands of separate cells can be analyzed in one experiment. These efforts also rely on scaling functional analysis of stem cell-based disease models, a vexing bottleneck for the field. “The CIRM iPSC Repository is the largest and most ambitious of its kind”, said Kevin Eggan, Professor of Stem Cell and Regenerative Biology at Harvard University, and Director of Stem Cell Biology at the Broad Institute’s Stanley Center for Psychiatric Research. Efforts underway in Dr. Eggan’s lab are directed at developing approaches to analyze large numbers of stem cell lines in parallel.

“The scale of the CIRM iPSC collection will allow us to investigate how variation that is common among many of us predisposes certain individuals to major mental illnesses such as autism and other neurodevelopmental disorders. We are incredibly excited about entering this long-term collaboration.”

Members of the Eggan and McCarroll labs at the Broad Institute’s Stanley Center for Psychiatric Research. (Image courtesy of Kiki Lilliehook)

From Cell Lines to Data

It’s clear from these stories, that the iPSC Repository is a unique and powerful tool for the stem cell research community. But for the rewards to be truly reaped, more tools are needed that will help scientists study these cell lines. This is where the CIRM Genomics Initiative comes into play.

Be sure to read Part 2 of our Stem Cell Tools series tomorrow to find out how our Genomics Initiative is funding the development of genomic and bioinformatics tools that will allow scientists to decipher complex stem cell data all the way from mapping the developmental states of cells to predicting the accuracy of stem cell-based models.

This blog was written in collaboration with Dr. Kiki Lilliehook, the Manager of the Stem Cell Program at the Stanley Center for Psychiatric Research at the Broad Institute in Cambridge, Massachusetts.

Building the World’s Largest iPSC Repository: An Interview with CIRM’s Stephen Lin

/ Freya Leask / Leave a comment

This blog originally appeared on RegMedNet and was provided by Freya Leask, Editor & Community Manager of RegMedNet. In this interview, Stephen Lin, Senior Science Officer at the California Institute Regenerative Medicine (CIRM), discusses the scope, challenges and potential of CIRM’s iPSC Initiative. 

 

Stephen Lin

Stephen Lin received his PhD from Washington University (MO, USA) and completed his postdoctoral work at Harvard University (MA, USA). Lin is a senior science officer at CIRM which he joined in 2015 to oversee the development of a $32 million repository of iPSCs generated from up to 3000 healthy and diseased individuals and covering both complex and rare diseases. He also oversees a $40 million initiative to apply genomics and bioinformatics approaches to stem cell research and development of therapies. Lin is the program lead on the CIRM Translating Center which focuses on supporting the process development, safety/toxicity studies and manufacturing of stem cell therapy candidates to prepare them for clinical trials. He was previously a scientist at StemCells, Inc (CA, USA) and a staff scientist team lead at Thermo Fisher Scientific (MA, USA).

Q: Please introduce yourself and your institution.

I completed my PhD at Washington University in biochemistry, studying the mechanisms of aging, before doing my postdoc at Harvard, investigating programmed cell death. After that, I went into industry and have been working with stem cells ever since.

I was at the biotech company StemCells, Inc for 6 years where I worked on cell therapeutics. I then joined what was Life Technologies which is now Thermo Fisher Scientific.  I joined CIRM in 2015 as they were launching two new initiatives, the iPSC repository and the genomics initiative, which were a natural combination of my experience in both the stem cells industry and in genetic analysis.  I’ve been here for a year and a half, overseeing both initiatives as well as the CIRM Translating Center.

Q: What prompted the development of the iPSC repository?

Making iPSCs is challenging! It isn’t trivial for many research labs to produce these materials, especially for a wide variety of diseases; hence, the iPSC repository was set up in 2013. In its promotion of stem cells, CIRM had the financial resources to develop a bank for researchers and build up a critical mass of lines to save researchers the trouble of recruiting the patients, getting the consents, making and quality controlling the cells. CIRM wanted to cut that out and bring the resources straight to the research community.

Q: What are the challenges of storage so many iPSCs?

Many of the challenges of storing iPSCs and ensuring their quality are overcome with adequate quality controls at the production step. The main challenge is that we’re collecting samples from up to 3000 donors – the logistics of processing that many tissue samples from 11 funded and nonfunded collectors are difficult. The lines are being produced in the same uniform manner by one agency, Cellular Dynamics International (WI, USA), to ensure quality in terms of pluripotency, karyotyping and sterility testing.

Once the lines are made, they are stored at the Coriell Institute (NJ, USA). During storage, there is a challenge in simply keeping track of and distributing that many samples; we will have approximately 40 vials for each of the 3000 main lines. Both Cellular Dynamics and Coriell have sophisticated tracking systems and Coriell have set up a public catalog website where anyone can go to read about and order the lines. Most collections don’t have this functionality, as the IT infrastructure required for searching and displaying the lines along with clinical information, the ordering process, material transfer agreements and, for commercial uses, the licensing agreements was very complex.

Q: Can anyone use the repository?

Yes, they can! There is a fee to utilize the lines but we encourage researchers anywhere in the world to order them. The lines are mostly for research and academic purposes but the collection was built to be commercialized, all the way from collecting the samples. When the samples were collected, the patient consent included, among other things, banking, distribution, genetic characterization and commercialization.

The lines also have pre-negotiated licensing agreements with iPS Academia Japan (Kyoto, Japan) and the Wisconsin Alumni Research Foundation (WI, USA). Commercial entities that want to use the cells for drug screening can obtain a license which allows them to use these lines for drug discovery and drug screening purposes without fear of back payment royalties down the road. People often forget during drug screening that the intellectual property to make the iPSCs is still under patent, so if you do discover a drug using iPSCs without taking care of these licensing agreements, your discovery could be liable to ownership by that original intellectual property holder.

Q: Will wider access to high quality iPSCs accelerate discovery?

That’s our hope. When people make iPSCs, the quality can be highly variable depending on the lab’s background and experience, which was another impetus to create the repository. Cellular Dynamics have set up a very robust system to create these lines in a rigorous quality control pipeline to guarantee that these lines are pluripotent and genetically stable.

Q: What diseases could these lines be used to study and treat?

We collected samples from patients with many different diseases – from neurodevelopmental disorders including epilepsy and neurodegenerative diseases such as Alzheimer’s, to eye disease and diabetes – as well as the corresponding controls. We also have lines from rare diseases, where the communities have no other tools to study them, for example, ADCY5 related dyskinesia. You can read our recent blogs about our efforts to generate new iPSC lines for ADCY5 and other rare diseases here and here.

Q: What are your plans for the iPSC initiative this year?

We’re currently the largest publicly available repository in the world and we aren’t complete yet. We have just under half of the lines in with the other half still being produced and quality controlled. Something else we want to do is add further information to make the lines more valuable and ensure the drug models are constantly improving. The reason people will want to use iPSCs for human disease modeling is whether they have valuable information associated with them.  For example, we are trying to add genetic and sequencing information to the catalog for lines that have it. This will also allow researchers to prescreen the lines they are interested in to match the diseases and drugs they are studying.

Q: Does the future for iPSCs lie in being utilized as tools to find therapeutics as opposed to therapeutics themselves?

I think the future is two pronged. There is certainly a future for disease modeling and drug screening. There is currently an initiative within the FDA, the CiPA initiative, is designed to replace current paradigms for drug safety testing with computational model and stem cell models. In particular, they hope to be able to screen drugs for cardiotoxicity in stem cells before they go to patients.  Mouse and rodent models have different receptors and ion channels so these cardiotoxic effects aren’t usually seen until clinical trials.

The other avenue is in therapeutics. However, this will come later in the game because the lines being used for research often can’t be used for therapeutics. Patient consent for therapeutic use has to be obtained at sample collection, the tissue should be handled in compliance with good lab practice and the lines must be produced following good manufacturing process (GMP) guidelines. They must then be characterized to ensure they have met all safety protocols for iPSC therapeutics.

There is already a second trial being initiated in Japan of an iPSC therapeutic to treat macular degeneration, utilizing allogenic lines that are human leukocyte antigen-compatible and extensively safety profiled. Companies such as Lonza (Basel, Switzerland) and Cellular Dynamics are starting to produce their own GMP lines, and CIRM is funding some translation programs where clinical grade iPSCs are being produced for therapeutics.

Further Reading