- 1. Induced Pluripotent Stem Cells Generation and their
Therapeutic Applications B.DEVADATHA M.Sc IInd YEAR BMB DEPT. OF
BIOCHEMISTRY & MOLECULAR BIOLOGY PONDICHERRY UNIVERSITYGUIDED
BY: Dr K.JEEVARATNAM PROFESSOR DEPT. OF BMB
2. INTRODUCTION Induced pluripotent stem cells (iPS cells) are
somatic cells that have been reprogrammed to a pluripotent state by
the introduction of specific factors. iPS cells are similar to
embryonic stem (ES) cells in several aspects such as morphology,
expression of pluripotency markers and the capacity to develop
teratomas. Yamanaka and Sir John Gurdon (2012) were awarded the
Nobel Prize in Physiology or Medicine "for the discovery that
mature cells can be reprogrammed to become pluripotent." 3. Somatic
Cell Nuclear Reprogramming 4. DISCOVERY OF iPS CELLS The human ES
cells derived from human blastocysts were first established by
Thomson et al. The iPS cells were first established in 2006 by
Takahashi and Yamanaka by the retrovirus-mediated transduction of
four transcription factors (c-Myc, Oct3/4, SOX2, & Klf4) into
mouse fibroblasts. Human iPS cells were established in 2007, by the
transduction of either the same set of transcription factors or
another set of transcription factors (Oct3/4, SOX2, Nanog, Lin28)
into human fibroblast. Human iPS cells have been reported to be
established from skin fibroblasts, keratinocytes, and mobilized
CD34+ hematopoietic stem/progenitor cells and differentiated T
cells from peripheral blood. 5. Reprogramming Factors Oct4
Expression is essential for the development of the inner cell mass
(ICM) in vivo, the derivation of ES cells and the maintenance of a
pluripotent state. Sox2 Transcription factor involved in the
self-renewal of ES cells. It has an important role in maintaining
ES-cell pluripotency and heterodimerizes in a complex with Oct4.
c-Myc Pleiotropic transcription factor that has been linked to
several cellular functions, including cell cycle regulation,
proliferation, growth, differentiation and metabolism. 6.
Reprogramming Factors Klf4 Expressed in a variety of tissues,
including the epithelium of the intestine, kidney and the skin.
Forced overexpression of Klf4 in ES cells inhibits differentiation
in erythroid progenitors, suggesting a role for this factor in
ES-cell function.Nanog Transcription factor that was involved in
maintaining EScell self-renewal and pluripotency. Nanog-deficient
ES cells completely lose their selfrenewal capability,
differentiating into extra-embryonic cell lineages.Lin-28 Expressed
in ES cells and during early embryogenesis but its expression
becomes restricted to several tissues during late embryogenesis and
adult life. 7. iPSC has been generated from Mouse (Yamanaka et al.,
2006) Humans (Yamanaka et al., 2007) Rhesus monkey (Liu et al.,
2008) Rats (Liao et al., 2009; Li et al., 2009) Canine (Shimada, H.
et al, 2010) Porcine ( Esteban, M. A. et al., 2009) Marmoset (Wu,
Y. et al., 2010) Rabbit (Honda, A. et al., 2010)Equine (Kristina
Nagy et al., 2011 ) Avian (Lu et al., 2011) 8. iPSC Therapeutic
Applications 9. iPSC Therapeutic Applications (Cont) Monogenic and
Polygenic Diseases Generation of iPS cells from patients with a
variety of genetic diseases with either Mendelian or complex
inheritance has been described. Include ADA-SCID, Gaucher disease
type III, Huntington disease, juvenile-onset type 1 diabetes
mellitus , Down syndrome. Neurodegenerative Disorders
Patient-specific fibroblasts offer a unique opportunity for
studying and modeling the effects of specific gene defects on human
neuronal development in vitro and other potential therapies for the
relevant neurogenetic disorders. Patient-derived iPS cells could be
subsequently differentiated in vitro into dopaminergic neurons for
treatment of Parkinson's disease. 10. iPSC Therapeutic Applications
(Cont) Degenerative Cardiac Diseases iPS cell based cell
replacement therapy is currently generating a great deal of
interest in the treatment of ischemic heart diseases since iPS
cells are capable of differentiating into patient-specific
functional cardiomyocytes. Obstacles in therapeutic application of
iPSCs in humans (i) Use of harmful oncogenes as part of the
reprogramming factors .(ii) Use of viral vectors for gene delivery
that carry the risk of insertional mutagenesis. (iii) Low
efficiency and slow kinetics of reprogramming.(iv) Lack of robust
and reliable differentiation protocols for human iPS cells. 11.
Generation of iPSC Derived Cardiomyocytes 12. iPSC in Modelling
Cardiac & Neural diseases 13. Conclusion With an aging
population, ever-increasing costs of healthcare and a decrease in
new drug discoveries, new and innovative ways of accelerating and
streamlining human disease study and treatment are required. Human
iPSC technology offers an unprecedented opportunity to develop
patient-specific and diseasespecific iPSC lines to be used for
regenerative therapies, disease study, drug safety and discovery.
The potential of iPS cell technology is tremendous, but this
technology is still in its infancy. To realize the full application
of iPS cells, it will be essential to improve the methodologies for
iPS cell generation and to precisely evaluate each clone and sub
clone of iPS cells for their safety and efficacy . 14. Reference
Takahashi K, Yamanaka S. Induction of pluripotent stem cells from
mouse embryonic and adult fibroblast cultures by defined factors.
Cell. 2006;126:663676. Shinya Yamanaka & Helen M. Blau. Nuclear
reprogramming to a pluripotent state by three approaches iPS cells:
A source of cardiac regeneration Yoshinori Yoshida, Shinya Yamanaka
Giovanni Amabile and Alexander Meissner .Induced pluripotent stem
cells: current progress and potential for regenerative medicine
Yingzi Oh,Heming Wei, Dongrui Ma, Xiaoming Sun,Reginald Liew.
Clinical applications of patient-specific induced pluripotent stem
cells in cardiovascular medicine Yoshida Y, Yamanaka S. iPS cells:
a source of cardiac regeneration. J Mol Cell Cardiol 2011;50:327e32
Alejandra M. Vitalea, Ernst Wolvetangb, Alan MackaySima.Induced
pluripotent stem cells: A new technology to study human diseases
15. Thank you
