outline What is a stem cell? Tissue stem cell Embryonic stem cell ips cell -production -advantages Applications Issue Conclusion

Transcription

1 outline What is a stem cell? Tissue stem cell Embryonic stem cell ips cell -production -advantages Applications Issue Conclusion 1

2 What is a stem cell? Definition: Self-renew themselves a number of times Differentiate into many types of cells embryonic stem cell Blastocyst (early embryo) 2

3 Properties of a stem cell Self-renew Identical stem cell Differentiate into specialized cells Specialized cell 3

4 Types of stem cells Tissue stem cell Embryonic stem cell ( ES ) Induced pluripotent stem cell ( ips ) Shinya Yamanaka 山中伸彌 2012 The Nobel Prize in Physiology or Medicine 4

5 Tissue stem cell (adult somatic stem cell) Many kinds of tissue stem cells are in our bodies Renew a number of times but not indefinitely Multipotent can make certain types of specialized cells differentiate blood stem cell only certain types of blood cell: red blood cells, white blood cells etc. 5

6 Embryonic stem cell (ES) Derived from a blastocyst Self-renew indefinitely Pluripotent can make almost all types of specialized cells Can be used to treat diseases 6

7 Therapy with ES Problems: Ethical concerns Immune rejection May cause tumor 7

8 ips cell A type of pluripotent stem cell Artificially derived from a somatic cell by inducing a "forced" expression of certain genes. First produced in 2006 from mouse cells and in 2007 from human cells. 8

9 How to make an ips cell? biopsy genetic reprogramming (add certain genes to the cell) adult somatic cell ips cell behaves like an embryonic stem cell four important genes in embryonic stem cells: Oct-3/4, SOX2, c-myc, and Klf4. 9

10 Therapy with ips 1)Take somatic cells from the patient (like skin cells) 2)Make ips cells (no need for embryos) 3)Use those ips cells to grow the specialized cells the patient needs to recover from the disease 10

11 Advantages of ips cells It s easy to get somatic cells from human bodies. No ethical problems No immune rejection 11

12 Applications Test drugs in the laboratory Study how diseases develop (disease modeling) Organs creating (mouse kidneys) Regenerative medicine (developing treatment for Parkinson s, diabetes, anemia) 12

13 Flowchart - regenerative medicine ( Sickle cell anemia) 13

14 Issues Because of the used gene c-myc,the created cells might be prone to form tumors. (20% of the mice developed cancer.) The process of creating ips without c-myc, takes longer and is not as efficient, but the resulting mice didn't develop cancer. 14

15 Conclusion ips vs ES - Easy to get somatic cells - No ethical problems - No immune rejection The gene c-myc might be prone to form tumors Application - Drug development - Organs transplantation (potential) - Regenerative medicine 15

16 Reference Euro stem cell : Yamanaka S. & et al. ; Generation of germlinecompetent induced pluripotent stem cells, Nature 2007;448: Takahashi & K. Yamanaka; Induction of pluripotent stem cells from mouse embryonic and adult fibroblast cultures by defined factors, Cell 2006;126: