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Replication NeoformationApoptosis  -cell mass IGF-1 Receptor pY ß-Cell Plasma Membrane ß-Cell Nucleus IGF-1 Induced Activation of IRS-2 Signaling in.

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Presentation on theme: "Replication NeoformationApoptosis  -cell mass IGF-1 Receptor pY ß-Cell Plasma Membrane ß-Cell Nucleus IGF-1 Induced Activation of IRS-2 Signaling in."— Presentation transcript:

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2 Replication NeoformationApoptosis  -cell mass

3 IGF-1 Receptor pY ß-Cell Plasma Membrane ß-Cell Nucleus IGF-1 Induced Activation of IRS-2 Signaling in ß-cells IGF-1 PH PTB IRS2IRS2 Shp-2 Nck Fyn Crk P P MEK Erk-1/-2 P p90 RSK Ras GTP Raf-1 Grb2 mSOS CELL SIZE MITOGENESIS ANTI-APOPTOTIC DIFFERENTIATION PKB ( Akt) PH P P PDK1 PKC  Mdm2 P mTOR P p21 CIP P P Foxo-1 P CREB BAD P P GSK3 P Procaspase-9 p70 S6K 4E-BP P P Protein Synthesis CELL SIZE Cyclin-D ß-Catenin p53 PI3’K p110 P85 PI (P) PIP3 Chris Rhodes Ph.D. PNRI, Seattle, WA.

4 Chris Rhodes Ph.D. PNRI, Seattle, WA. THE FORMULA FOR ß-CELL MASS - (Mitogenesis + Size + Neogenesis) - Apoptosis = Growth (Mitogenesis + Size + Neogenesis) > Apoptosis Increased ß-mass (i.e. compensation for insulin resistance): Apoptosis > (Mitogenesis + Size + Neogenesis) Decreased ß-mass (i.e. Type-2 diabetes):

5 Chris Rhodes Ph.D. PNRI, Seattle, WA. 0 10 20 Fasting Glucose (mM/L) 0 200 400 Fasting Insulin (pmol/L) 0 500 1000 Plasma FFA ( µmol/L) 50 100 150 ß-Cell Mass (% change) 0 2.5 5 Amyloid Deposit (% Pancreatic Area) INCREASING AGE AND/0R DEGREE OF OBESITY (increasing peripheral insulin resistance) Fasting Plasma Glucose Fasting Serum Insulin Circulating FFA Pancreatic ß-Cell Mass Islet Amyloid Deposit NormalAdaptation Glucose Intolerant Type-2 Diabetes The Pathogenesis of Obesity-linked Type-2 Diabetes [TIMM (2002) 8: 375-384]

6 Chris Rhodes Ph.D. PNRI, Seattle, WA. Type-2 Diabetes - A Question of Balance - PERIPHERAL INSULIN RESISTANCE ß-CELL MASS & FUNCTION Non-Diabetic State PERIPHERAL INSULIN RESISTANCE ß-CELL MASS & FUNCTION Diabetic State

7 Endodermal precursorPancreatic precursor Endocrine precursors Exocrine precursor InsulinGlucagon Exocrine Ductal Time ? Lineage relationships during pancreatic development Liver Duodenum Jensen and Jensen, 2002.

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9 In order to obtain self-derived stem cells, adult cell nuclei are transferred to human oocytes, obtained as excess material from in-vitro fertilization. This procedure was used to create the sheep “Dolly”, and is at present highly controversial, and ethically debated, as the resulting blastula from the procedure could be transferred to a human foster mother, and give rise to a complete human being. Figure reproduced by permission from Solter et al. ScienceMag. Human therapeutic cloning.

10 HNF1a NeuroD Ngn3 HNF6 ISL1 HES1 HNF4 + Pax4 Pax6 HB9 Nkx2.2Nkx6.1 Insulin Nkx2.2 Amylase, CPA, trypsin Nkx6.1 PDX1 HNF3b PDX1 vHNF1 - Pax4 Glucagon - Nkx2.2 Nkx6.2 - PDX1 Brn4 Notch1 p48 Endodermal cells Pancreas/ Duodenal precursors Pancreas precursors Exocrine precursors Exocrine cells Pancreas precursors, Endocrine patterned Pro-endocrine cells Endocrine cells Non-b-cells b-cell precursors  -cells  -cells Pancreas precursors, Differentiation suppressed. Cell intrinsic factors in pancreatic development. Duct cells? remaining epithelial Precursors? intercalated duct/centroacinar cells? J. Jensen, 2002

11 ES-cells, Allo ES-cells, self EG-cells GIP cells Endocrine tumor cells Liver Pancreatic Stem Cells, Adult, Auto. Adult  -cells, Auto Islets, Xeno Adult  -cells, Allo Pancreatic Stem Cells Embryonic, Allo. Transplantable  -cells Differentiation Trans differentiation Therapeutic cloning Expansion Differentiation Expansion Differentiation Expansion Differentiation Modification Expansion Modification Isolation, heavy immunosuppresion Isolation Expansion? Isolation Expansion Only for NIDDM

12 Extrapancreatic insulin-producing cells in multiple organs in diabetes Kojima et al. PNAS 2004; 101:2458-2463 Proinsulin mRNA and proinsulin protein induced with multiple forms of hyperglycemia in marrow derived CD45+ murine cells (in liver, adipose tissue, spleen, bone marrow and thymus[some acinar pancreas but not remnant islets]) STZ rat and mice; ob/ob mice/IP glucose X 3 days Transgenic GFP driven by mouse insulin promoter gave complete concordance with presence proinsulin Bone marrow transplantation experiments (bta galactosidase postive cells)indicated bone marrow derivation-Post glucose injections 30% of bone marrow cells positive for proinsulin and 75% of proinsulin positive cells beta galactosidase positive. Proinsulin and somatostatin protein in same cells of liver of glucose injected mice.


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