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I. Stem cells II. Differential gene expression and cell fate III. Why manipulate stem cells? IV. Potential sources of therapeutic cells V. Concluding thoughts.

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Presentation on theme: "I. Stem cells II. Differential gene expression and cell fate III. Why manipulate stem cells? IV. Potential sources of therapeutic cells V. Concluding thoughts."— Presentation transcript:

1 I. Stem cells II. Differential gene expression and cell fate III. Why manipulate stem cells? IV. Potential sources of therapeutic cells V. Concluding thoughts

2 pluripotent stem cell committed cell

3 pluripotent- having the potential to develop into any cell type of the body

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7 I. Stem cells II. Differential gene expression and cell fate III. Why manipulate stem cells? IV. Potential sources of therapeutic cells V. Concluding thoughts

8 Genes are made of DNA

9 DNA is within the nucleus of each of our cells.

10 This DNA is identical in each of the cells of our bodies…

11 …even though different cells have very different structures and functions

12 Q: How do cells with identical genetic compositions become so different from one another?

13 A: Different cells express different subsets of their genes. Gene A Gene B Gene A Gene B In neurons, gene A is expressed but not gene B: In muscle cells, gene B is expressed but not gene A:

14 Gene A Gene B (muscle cell specific transcription factors) (promoter of gene B) In muscle cells, gene B is expressed because muscle cells have transcription factors that bind to gene B’s promoter.

15 Gene A Gene B In muscle cells, gene B is expressed because muscle cells have transcription factors that bind to gene B’s promoter.

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22 I. Stem cells II. Differential gene expression and cell fate III. Why manipulate stem cells? IV. Potential sources of therapeutic cells V. Progress on stem cell therapeutics

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25 I. Stem cells II. Differential gene expression and cell fate III. Why manipulate stem cells? IV. Potential sources of therapeutic cells A.Adult stem cells B.Embryonic stem cells (IVF embryos) C.Induced pluripotent stem cells D.Embryonic stem cells (SCNT-derived) E.Transdifferentiation V. Concluding thoughts

26 Bone marrow contains Hematopoetic Stem Cells

27 irradiation

28 (injection with bone marrow)

29 Adult stem cell types that have been tested clinically Hematopoetic stem cells Mesenchymal stem cells Neural stem cells Adipose stem cells Lin et al., 2013

30 Lin, et al., 2013 Most stem cell clinical trials have used adult stem cells

31 Adult Stem Cell Therapies pros cons no ethical dilemmas autologous (self) donations are possible cells need not be manipulated or grown in culture no risks of teratomas (tumors) few tissues are represented by adult stem cells those tissues that DO have them have very few if not autologous, MUST be tissue type matched evidence of clinical efficacy limited to HSCs cannot be amplified or maintained in culture

32 I. Stem cells II. Differential gene expression and cell fate III. Why manipulate stem cells? IV. Potential sources of therapeutic cells A.Adult stem cells B.Embryonic stem cells (IVF embryos) C.Induced pluripotent stem cells D.Embryonic stem cells (SCNT-derived) E.Transdifferentiation V. Concluding thoughts

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34 Deb and Sarda, 2008 Animal Models in which hESC-Derived Cells have been Effective

35 Geron Corporation hESC-derived oligodendrocyte progenitors for treatment of spinal cord injuries (Daley, 2012) -in animal models, these cells car repair damaged neurons -the first hESC clinical study to overcome FDA restrictions -four patients enrolled -no publications yet; no reported negative effects, but unclear if treatments were effective Clinical Trials using hESCs

36 2009-present Advanced Cell Technology (ACT) hESC-derived retinal pigment epithelial cells are being used to treat macular degeneration (Schwartz,et al. 2012) -started with 2 patients, both showed vision improvement and no signs of tumors after 4 months -study is continuing with higher doses of cells and in more patients Clinical Trials using hESCs, cont.

37 ESCs from IVF pros cons source tissue plentiful cells divide infinitely in culture easily programmable cells immune response problems ethical controversy tumor risks

38 I. Stem cells II. Differential gene expression and cell fate III. Why manipulate stem cells? IV. Potential sources of therapeutic cells A.Adult stem cells B.Embryonic stem cells (IVF embryos) C.Induced pluripotent stem cells D.Embryonic stem cells (SCNT-derived) E.Transdifferentiation V. Concluding thoughts

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40 I. Stem cells II. Differential gene expression and cell fate III. Why manipulate stem cells? IV. Potential sources of therapeutic cells A.Adult stem cells B.Embryonic stem cells (IVF embryos) C.Induced pluripotent stem cells 1.issues with iPSCs 2.progress with iPSCs D.Embryonic stem cells (SCNT-derived) E.Transdifferentiation V. Concluding thoughts

41 Takahashi and Yamanaka 2006

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43 DNA inserted randomly could create problems with endogenous DNA. DNA insertions are inherited by all progeny of manipulated cell. The genes added could cause cells to be more prone to division.

44 New iPSC protocols do NOT require insertion of foreign DNA Exposure of differentiated cells to chemical treatments caused them to become pluripotent (Masuda et al., 2013). Protein transduction of somatic cells can produce iPS cells (Nemes et al., 2013). Mouse lymphocytes were induced to become pluripotent via acid treatment (Obokata et al., 2014).

45 Stadtfield & Hochedlinger 2010 With iPSCs, the pluripotency must be tested

46 I. Stem cells II. Differential gene expression and cell fate III. Why manipulate stem cells? IV. Potential sources of therapeutic cells A.Adult stem cells B.Embryonic stem cells (IVF embryos) C.Induced pluripotent stem cells 1.issues with iPSCs 2.progress with iPSCs D.Embryonic stem cells (SCNT-derived) E.Transdifferentiation V. Concluding thoughts

47 Many cell types have been derived from human iPS cells hepatocytes (Takebe et al., 2014) neurons (Prilutsky et al, 2014) folliculogenic stem cells (Yang et al., 2014) cardiomyocytes (Seki et al., 2014) pancreatic beta cells (Thatava et al, 2011)

48 First iPSC clinical trial to begin this year lab of Dr. Masayo Takahashi at Riken in Kobe, Japan 6 patients with macular degeneration in trial iPSCs will be reprogrammed in culture to become retinal pigment epithelium once 50,000 cells per patient are produced, these will be introduced back into the retinas

49 Grskovic, et al. 2011

50 Successful “disease in a dish” models Familial dysautonomia, a genetic disease of autonomic nervous system Rett Syndrome, a disease within the autism spectrum HGPS (progeria), premature aging Parkinson’s, degradation of midbrain dopaminergic neurons leading to loss of motor activity Grskovic, et al. 2011

51 iSPCs pros cons patient-derived pluripotent cells once established, cells divide infinitely in culture easily programmable cells less ethical controversy than ESCs produce excellent tools for studying disease cells require a lot of manipulation to become iSPC evidence of immunogenicity of iPSCs (Fu, 2013) low rate of induced pluripotency (~.2%) tumor risks

52 I. Stem cells II. Differential gene expression and cell fate III. Why manipulate stem cells? IV. Potential sources of therapeutic cells A.Adult stem cells B.Embryonic stem cells (IVF embryos) C.Induced pluripotent stem cells D.Embryonic stem cells (SCNT-derived) E.Transdifferentiation V. Concluding thoughts

53 Freeman, 2012

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57 ESCs from SCNT pros cons cells divide infinitely easily programmable cells genetically identical to patient great for disease modeling ethical controversy will require oocyte donors not tested much with human cells

58 I. Stem cells II. Differential gene expression and cell fate III. Why manipulate stem cells? IV. Potential sources of therapeutic cells A.Adult stem cells B.Embryonic stem cells (IVF embryos) C.Induced pluripotent stem cells D.Embryonic stem cells (SCNT-derived) E.Transdifferentiation V. Concluding thoughts

59 Transdifferentiation Graf, 2011

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61 I. Stem cells II. Differential gene expression and cell fate III. Why manipulate stem cells? IV. Potential sources of therapeutic cells A.Adult stem cells B.Embryonic stem cells (IVF embryos) C.Induced pluripotent stem cells D.Embryonic stem cells (SCNT-derived) E.Transdifferentiation V. Concluding thoughts

62 ESCsiPSCs embryos high good somatic cells very high some? good derivation cancer risk immunogenicity growth in culture ability to program

63 ESCs are currently considered the “gold standard” for pluripotency. Current research is investigating whether iPSCs are truly equivalent to ESCs. Many scientists developing iPSCs still must use ESCs for comparison in their experiments.

64 macular degeneration Parkinson’s Type II Diabetes Altzheimer’s heart disease spinal cord injuries burns Huntington’s Conditions that might be alleviated using stem- cell derived transplantations (a partial list)

65 cancer risk from cultured cells immune response from cultured cells creating cultured cells to have all the functions of those cells produced by the body the necessity of producing a LOT of the target cells in culture creating cultured cells that integrate with host tissues Challenges to cell culture-derived transplantations

66 useful as a way to test drugs without experimenting on patients a means to generate therapies specific to specific patients can be used also to study diseased cells and figure out what is wrong with them iPSCs are outstanding tools for disease modeling


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