Martin Pera stem cells and the future of medicinePresentation Transcript
Stem Cells and the Future of Medicine Martin Pera Eli and Edythe Broad Center for Regenerative Medicine And Stem Cell Research at USC
What is regenerative medicine? An emerging field of therapeutics that has as its goal the restoration of normal function in conditions characterised by cell loss, caused by disease or injury. Restoration may involve the administration of cells to replace damaged tissue, alone or in combination with synthetic scaffolds, or the administration of pharmaceuticals that help drive the patient’s tissue to repair itself.
What is a stem cell? A primitive cell with two key properties: Self renewal, or the ability to divide many times to produce more stem cells The ability to undergo differentiation or specialisation to give rise to mature functional cells Stem cells have the potential to replace dead or damaged cells in diseased tissue
Tissue Stem Cells
Clinical uses of tissue stem cells Bone marrow and cord blood-hematopoietic disorders, leukemias Mesenchymal stem cells-cartilage repair Neural stem cells-early phase trials
Limitations with tissue stem cells Rare-minority population in most tissues ie less that 1/1000 Usually have a limited repertoire-can only give rise to a few types of differentiated cell Not well characterised in many tissues Difficult to propagate and expand in numbers outside of the body
Nov 98- human embryonic stem cells discovered
Human embryonic stem cells Derived from spare embryos before specialised tissue of the body begin to form Can multiply indefinitely in laboratory cultures Retain the ability of embryonic cells to turn into any type of tissue
Early stages of human development
hESC differentiation Teratoma formed by human ES cells shows differentiation into a wide variety of cell types
ES cell differentiation follows the road mapof embryogenesis
Partial list of cell types derived from human ES cells in vitro Nerve, astrocyte, oligodendrocyte Hematopoietic stem cells Insulin producing cells Cardiomyocytes Hepatocytes Endothelial cells Bone forming cells Motor neurons Trophoblast and yolk sac cells
Somatic cell nuclear transfer and reprogramming Many species of mammal have now been cloned. Can cloning technology be used to surmount immunological barriers to stem cell transplantation?
Somatic cell nuclear transfer
Induced pluripotent stem cellsMatching cells for patients Skin cells taken from adult tissue are grown in a dish 2-4 genes found in embryonic stem cells are introduced Adult cells are converted to pluripotent stem cells These stem cells provide a match for the patient
Induced Pluripotent Stem Cells: The potential Creation of large banks of stem cell lines of desired HLA haplotypes for tissue matching Development of in vitro models of diseases with complex genetic susceptibility Partial reprogramming to heal tissues: exocrine pancreas to endocrine pancreas
Induced Pluripotent Stem Cells: Challenges Can we make these cells without genetic modification? Are they really equivalent to human embryonic stem cells Embryonic stem cell research is still needed as is research in somatic cell nuclear transfer
Stem cell research will revolutionise medicine Powerful new tools to study human biology in health and disease Normal human cells to study in the laboratory-use to develop new drugs. Alternative to animal models or direct tests on human guinea pigs. Cells for replacement therapy in devastating conditions involving cell loss or injury New understand of how the body’s natural healing process, how and why it fails, and how to improve healing
Stem Cells to Study Disease Marchetto et al. Cell Stem Cell 3: 649, 2008 Amyelotrophic lateral sclerosis
Stem Cells to Study CNS Development Cortical structures in vitro from human ES cells Eiraku et al. Cell Stem Cell 3: 519, 2008
The Eli and Edythe Broad CenterFor Regenerative Medicine and Stem Cell Research
Broad CIRM Center Opening29 October 2010
The Center Established April 2006 Built on strengths in developmental biology, clinical research, stem cell biology at Keck School and CHLA $50 million dollar commitment by USC to program development Now 12 PIs, over 100 staff, four core laboratories. Four administrative staff
Center Research StrategyDiscovery Technology Treatment Patient treatment And clinical trials Platform technologies: Large scale production Drug discovery, functional genomics KSOM clinical groups Engineering, Biotech, pharma Basic discoveries in stem cell biology
Center Discovery Research ThemesStem Cell Biology Embryonic stem cell growth and differentiation; reprogramming adult cells Biology of tissue regeneration and repair; how stem cells are controlled in the body How cells are shaped to form organs
Embryonic stem cells from rat Chimeric rat pups made from embryonic stem cells. Chimeras are black and white.
An important new tool for basic research and drug discovery Workers have tried for 20 years to make rat embryonic stem cells Rats are widely used in physiology and pharmacology and drug discovery Until now there have been no tools to make specific modifications in the rat genome to create disease models, like we can in mouse (Nobel prize 2007) Ying used his new discoveries about embryonic stem cell growth regulation (ES cell self renewal as a default pathway) to make rat ES cells for the first time
Science Magazine Top Ten Breakthroughs of 2010 Gene knockout rat technology developed by Dr. Qilong Ying named one of Top Ten Breakthroughs of 2010 by Science magazine
Understanding tissue repair and regeneration Lower vertebrates can regenerate limbs, hearts and kidneys. How does this work? What stops this happening in mammals? How do tissue stem cells function in repair?
Skeletal regeneration In Mammals Dr. Francesca Mariani
Stem Cell Transplantation Biology Dr. Gregor Adams and colleagues have identified a drug that promotes engraftment of blood stem cells in transplant recipients. The findings may lead to more effective treatment of blood disorders and cancers.
Blindness Macular degeneration is a major cause of blindness in the aging population
Retinal pigment epithelium and macular degeneration, a major cause of blindness
2000- hESC can form neural tissue in vitro. The eye forms as an outgrowth of the embryonic brain
2004-directed neural differentiation Treatment with the embryonic head inducer noggin induces differentiation of human ES cells into primitive neural tissue Nestin and Sox-2, markers of early neurogenesis Groppe et al. Nature 420: 636, 2002 Conservation of developmental mechanisms
Retinal pigment epithelium from human neural progenitors Doheny Eye Institute and Center Collaboration
The road to the clinic: ES cells for eye disease
CIRM Macular Degeneration Disease Team:The California Project to Cure Blindness USC Doheny Eye Institute (Mark Humayun, PI; David Hinton Co-PI; Vas Sadda, Biju Thomas, Martin Pera) UCSB Macular Degeneration and Stem Cell Centers (Dennis Clegg, Co-PI; Lincoln Johnson) UCL London Project to Cure Blindness (Pete Coffey, Partner PI funded by MRC) Caltech Biology and Chemistry (Scott Fraser, Bob Grubbs, Yu-Chong Tai) City of Hope Center for Biomedicine and Genetics GMP Facility (Larry Couture)
Chemical genomics and stem cells Stem cells can be used in high throughput screens to discover new small molecules that modulate tissue regeneration or repair Important tool to understand stem cell control pathways-but also leads for drug development
Dr. Kahn has focused on WNT signaling, a key pathway in development and cancer The Wingless mutation affects wing development in the fruit fly embryo. The Wnt gene, discovered as a virus integration site for mouse breast cancer induction, is involved in many cancers. Like many developmental pathways, Wnt is evolutionarily conserved and widely deployed in stem cell regulation in many tissues.
USC Center for Molecular Pathways and Drug Discovery A joint venture between the Broad Center at USC and the USC Norris Cancer Center Directed by Professor Michael Kahn (Broad) and Professor Heinz Lenz (Norris Cancer Center) Mission: discover new chemicals that modulate critical signaling pathways in stem cells and cancer and develop new therapeutics
CBP/Catenin Antagonists Effectively Eliminate Cancer Stem Cells When Used in Combination Chemotherapy Mice are cancer free
Cancer Therapy Program at NCI Considers the Development of PRI-724 its Highest Priority“PRI-724 is a first in class and first in human agent. PRI-724 is a novel cancer stem cell targeting agent…” There are no other Wnt signaling pathway inhibitors targeting transcription. Phase I clinical trial 7 day continuous infusion of C82 (primary endpoint MTD/biological activity, secondary endpoint proof of principle Survivin expression in tumor and CTC)-later this year No toxicity to normal tissues indogs at 200X IC50 (the dose that kills 50% of tumor cells)Ph
Zinc finger nuclease-based stem cell therapy for AIDS - $14 million CIRM Disease Team award City of Hope AIDS lymphoma group Paula CannonAssociate Professor, Microbiology & Immunology USC Keck School of Medicine Dave DiGiusto John Rossi John Zaia (PI)
The AIDS virus must enter cells to infect them. HIV-1 enters cells by binding to CD4 and a co-receptor, CCR5 CD4 and CCR5 are proteins on the surface of cells that the HIV-1 targets.
About 1% of people have 2 copies of a mutant version of CCR5 gene called CCR5D32, and theyare consequently extremely resistant to HIV-1.
The virus cannot enter their cells.
Can we make AIDS resistant cells byblocking CCR5 expression in hematopoietic stem cells and their progeny? HIV CLP T cells B cells ProB Bone marrow stem cells are the source of T Cells and macrophages that the AIDS virus infects GMP HSC Macrophages Erythrocytes platelets CMP MEP
DNA cleaving domain Zinc finger nucleases to disrupt the CCR5 gene Zinc fingers target specific DNA sequences. The attached nucleases chop the DNA. DNA binding domain ZFNs bind to the CCR5 gene They cut the CCR5 gene The cell repairs this break, but in a way that also destroys the CCR5 gene
Pre-clinical testing Human hematopoietic stem cells Treat with CCR5 ZFNs Transplant into special ‘NSG’ mice HIV-1 Human T cells in mouse blood HIV Infection Day -1 Day 0 Months 2 - 4
ZFN-treated HSC generate human cells in the mice that are HIV-resistant Ctrl. HSC HIV-1infected ZFN HSC CD4 T cells ZFN Ctrl. Ctrl. CD8 Human cells killed by HIV-1 infectionin untreated mice thymus CD4 CD8 0 2 4 6 8 spleen weeks post-HIV infection CD4 CD45 lung Human cells are normal in ZFN-treated mice CD14 SSC Gut mucosa CD3 Holt et al. Nat Biotechnol. 2010 Aug;28(8):839-47
Other USC Bioscience Interdisciplinary Initiatives Neuroscience Biomedical Nanoscience Clinical and Translational Sciences Institute Funded by NIH $60 million to facilitate translational research