Inman_Stem_Cells_05

Stem Cells in Research ,[object Object],Denise Inman, PhD University of Washington Department of Neurosurgery

Overview ,[object Object],[object Object],[object Object],[object Object],[object Object]

Early Development Fertilized egg Totipotent stem cells Totipotent : Can become any cell in body or placenta Fate Decision Pluripotent stem cells Blastocyst Pluripotent : Can become any cell in body Implantation Gastrulation Fate Decision Multipotent stem cells Primary Germ Cells Endoderm (inner) Mesoderm (middle) Ectoderm (outer) Multipotent : Can become any cell within a specific germ layer or cell lineage Embryonic stem cells come from inner cell mass of blastocyst.

Embryonic Stem Cell Characteristics ,[object Object],[object Object],[object Object],endoderm mesoderm ectoderm Courtesy of James Thomson, U. Wisconsin-Madison

Is that an Embryonic Stem Cell? Embryonic stem cells injected into a SCID mouse will grow into teratomas, tumors of the germ cell layers. Individual ESCs under the correct conditions will make many different cell types. The true potential of stem cells can only be assessed retrospectively SCID Mouse: Severe Combined ImmunoDeficiency

Stem Cells: From Embryonic to Adult Embryonic stem cells are those removed from the blastocyst before the fate decision from pluripotentiality to multipotentiality. Adult stem cells are those multipotential cells that persist in fully developed tissues. These cells never differentiated into the mature cell types of the tissues in which they reside. http://www.brown.edu/Courses/BI0032

Adult Stem Cells ,[object Object],[object Object],[object Object],[object Object],[object Object],Neural stem cells in culture. One cell is extending a process.

Adult Stem Cells – Bone Marrow NIH: stemcells.nih.gov/ info/basics/basics4.asp Major repository of adult stem cells -Hematopoeitic -Mesenchymal Give rise to immune system cells Constant turnover

Stem Cell Phenotype Fate dictated by environment… Shihabuddin, et al., J. Neuroscience 20(23) 8727-8735, 2000 Neural stem cells Neurons Astrocytes Oligodendrocytes Oligodendrocyte Progenitor Cells Stem cells placed in brain become neurons… Stem cells placed in spinal cord become glial cells…

Re-cap: What are stem cells? ,[object Object],[object Object],[object Object],[object Object],[object Object]

Overview ,[object Object],[object Object],[object Object],[object Object],[object Object],[object Object],[object Object],[object Object],[object Object],[object Object]

Cell Lines ,[object Object],[object Object],[object Object],Plate Exponential Growth Remove from plate Replate at lower density

Culturing Embryonic Stem Cells Obtain stem cells from 1. Remove inner cell mass 2. Put cells in dish with feeder layer 3. Cells divide Somatic Cell Nuclear Transfer Oocyte without nucleus Inject nucleus from adult somatic cell Blastocyst Fertilized egg Blastocyst + Sperm Oocyte In Vitro Fertilization

Origins of ES Cell Lines ,[object Object],[object Object],[object Object],[object Object],[object Object],[object Object],New England Journal of Medicine, Wellcome Trust

Somatic Cell Nuclear Transfer ,[object Object],[object Object],Limited success: ~25 percent of nuclear transfers led to a blastocyst; 35 percent of blastocysts led to establishment of cell lines Patient-specific embryonic stem cells derived from human SCNT blastocysts. Science 308(5729):1777-1783, 2005. Removing the egg nucleus before transferring a somatic cell nucleus Roslin Institute http://www.roslin.ac.uk/library/

hES Cell Lines in the US ,[object Object],[object Object],[object Object],[object Object]

Promises and Perils of Stem Cells ,[object Object],[object Object],[object Object],[object Object],[object Object],What’s at stake?

What can ESCs do for you? ,[object Object],[object Object],[object Object],[object Object]

Why Clone? ,[object Object],[object Object],[object Object],[object Object],[object Object],Therapeutic and Reproductive Cloning

How Promising are Adult Stem Cells? ,[object Object],[object Object],[object Object],[object Object],[object Object]

Adult Stem Cell Clinical Trials ,[object Object],[object Object],[object Object],[object Object]

Potential Beyond Cell Replacement ,[object Object],[object Object],[object Object],[object Object],[object Object],[object Object]

Beyond the Embryo ,[object Object],[object Object],[object Object]

ESCs without the E ,[object Object],[object Object],[object Object],[object Object],[object Object],Issues: How far back can dedifferentiation go? Muscle cells Multipotent progenitors

ESCs without the E ,[object Object],[object Object],Issues: Is there harm in removing a cell? Could a cell line be established with one cell? Is cell at this stage totipotent? Remove cell Establish cell line Embryo

ESCs without the E ,[object Object],[object Object],Issues: Can markers of organismic death be found? Can pluripotent stem cells be derived from dead embryos? If so, will they be chromosomally (and otherwise) normal?

Parthenogenesis ,[object Object],[object Object],[object Object],Oocyte Blastocyst Establish cell line

ESCs without the E ,[object Object],[object Object],Altered Nuclear Transfer Embryo Remove altered nucleus to oocyte Somatic cell Oocyte Cell Division Blastocyst

ESCs without the E ,[object Object],[object Object],[object Object],[object Object],[object Object],Creative thinking, possible solutions to an ethical dilemma. Research has yet to determine if one or more of these proposals are possible.

Recent Research ,[object Object],[object Object],[object Object],[object Object]

Summary ,[object Object],[object Object],[object Object],[object Object],[object Object],[object Object],[object Object]

Conclusion ,[object Object],[object Object]

Inman_Stem_Cells_05

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