Welcome Everyone

Welcome Everyone

To know “transdifferentiation” Sun, Luguo 2013.03.25

CONTENTS • What is transdifferentiation? • Phenomenon of transdifferentiation • Studies of transdifferentiation • Significance of transdifferentiation studies

What? • Differentiation • De-differentiation • Trans-differentiation

What? • Differentiation -- the process by which a less specialized cell becomes a more specialized cell type • De-differentiation • Trans-differentiation

What? • Differentiation differentiation Pluripotent SC multipotent SC Adult SC Unipotent SC Progenitor cells Mature and differentiated cells SC: stem cell

What? • Differentiation • De-differentiation --refers to a reduction in the molecular and/or functional properties of a differentiated cell type • Trans-differentiation

differentiation iPSC What? • De-differentiation PluripotentSC Multipotent SC Unipotent SC Progenitor cells Mature and differentiated cells

2012 Nobel Prize in Physiology or Medicine "for the discovery that mature cells can be reprogrammed to grow new cells." Shinya Yamanaka John Gurdon

What? • Differentiation • De-differentiation • Trans-differentiation --Broadly, it refers to converting one sort of cell into another --Strictly, it refers to the switch between one differentiated cell type to another

What? • Trans-differentiation differentiation Differentiated cells Another type of Differentiated cells Stem cells Differentiated C. of different lineage Trans-differentiation

What? Another type of Differ. cells Trans-D Differentiated cells De-D De-Differentiated cells • Molecular Basis: • Every cell has a complete and identical set of genes • Differential gene expression in different cell type • “Master switch genes” are fate determining --expressed in one cell type but not another --are responsible for the formation of different tissues. --are transcription factors

Phenomena --Naturally occurring --The concept of “transdifferentiation” was first introduced in 1974 • Animals: For repairing e.g: newts, chick repair of damaged or removed lens Iris pigment epithelial cells De-differentiated Len cells (keratinocytes) Eguchi and Okada, 1973,1977,1991

Phenomena • in human: A major dysfunction and pathologic • metaplasia Barret’s metaplasia oesophageal squamous epithelium Intestinal-like tissue Trans-Diff High risk of tumorigenesis • Liver fibrosis Hepatic stellate cells ( quiescent) Fibrotic stimulus Myofibroblast-like cells (collagen-producing) fibrosis

Phenomena ‘ • EMT（Epithelial to mesenchymal transition) ECM+ E-cadherin+ ZO-1 + Fibronectin + vimentin + Singh,A et al Oncogene, 2010 ——Required for tissue morphogenesis during embryonic development ‘ ——Contributes to increased metastasis and drug resistance in cancer ——includes morphogenetic and gene expression changes

Studies ——Transdifferentiation experiments have been performed in vivo and in vitro in various systems

Studies • Candidate cells Small jump: • cell types with proximal lineage Pancreas cells Liver cells • Neighboring tissues Insulin-producingβcells Pancreatic exocrine cells big jump: • Cells with different lineage Fibroblasts: easy -access, more abundant

Studies • Methods of transdifferentiation • Transfection of “Master switch” genes • Addition of specific molecules including chemicals, proteins et al. • Cell-cellular extract co-culture • Cell-cell co-culture

Studies • pancreatic cells hepatocytes • Fibroblasts other cells

hepatocytes • pancreatic cells • 2000-2003：in vitro （地塞米松） + C/EBPβ C/EBPβ pancreatic duodenal homeobox-1 Pdx-1 Biochem J , 2003; J Cell Physi, 2006;

pancreatic cells • hepatocytes High glucose Pancreatic cell extract Transplantation of the induced pancreatic cells into diabete mice could alleviate the symptom with the elevated level of blood insulin. Transdifferentiation of liver cells to pancreatic cells has considerable clinical significance since it could be a potential therapy for diabetes.. Nature, 2000; PNAS, 2002;

Fibroblasts other cells • Fibroblasts→skeletal muscle cells • Fibroblasts→neuronal cells • Fibroblasts→myocardial cells • Fibroblasts→blood cells

Fibroblasts other cells • Fibroblasts→skeletal muscle cells • Fibroblasts→neuronal cells Mice fetal fibroblasts Skeletal muscle cells + MyoD • Fibroblasts→myocardial cells + MyoD Other types of cells • Fibroblasts→blood cells MyoD only expresses in skeletal muscle cells and is the “Master switch gene” cell, 1987; Science,1988,1989;PNAS, 1989,1990;

Fibroblasts other cells • Fibroblasts → skeletal muscle cells • Fibroblasts → neuronal cells 2010年：amazing study Nature, 2010 • Fibroblasts → myocardial cells • Fibroblasts →blood cells BAM: Brn2, Ascl1, Myt1I Hign efficiency :20% Form synapses and transmit action potentials

Fibroblasts other cells • Fibroblasts→skeletal muscle cells • Fibroblasts→neuronal cells 2011年：followed Mouse Healthy human patients • Fibroblasts→myocardial cells human Human Fetal/ postnatal Ascl 1 Nurr1 Lmx1a • Fibroblasts→blood cells +Lmx1a,FoxA2 + Neuro D1 dopamine neuron iN cells (Dies in Parkinson’s disease) PNAS, 2011(2)，Nature 2011（2）,

Fibroblasts other cells • Fibroblasts→skeletal muscle cells • Fibroblasts→neuronal cells 2011年：more closer for clinical application • Fibroblasts→myocardial cells Mouse, human EFs Adult human + 4 motor neuron specific TFs • Fibroblasts→blood cells MiR-9 MiR-124 (or +Ascl1 +Myt1l) MiR-124 +Brn2 +Myt1l No dedifferentiatin iN cells iN cells Spinal moter neuron (iMNs) Cell stem cell , 2011.9, Nature,2011

Fibroblasts other cells • Fibroblasts→skeletal muscle cells • Fibroblasts→neuronal cells Cardiac fibroblasts in the infarcted myocardium scar + Myocardin Cardiomyocytes • Fibroblasts→myocardial cells post-natal cardiac or dermal fibroblasts • Fibroblasts→blood cells Gata4, Mef2c,Tbx5 Cardiomyocytes FASEB J, 2007; Cell, 2010; Nature cell biology, 2011

Fibroblasts other cells • Fibroblasts→skeletal muscle cells • Fibroblasts→neuronal cells • Fibroblasts→myocardial cells • Fibroblasts→blood cells Mice fetal or adult fibroblasts PU.1 ,C/EBPalpha/beta macrophages PNAS, 2008

Studies • pancreatic cells hepatocytes • Fibroblasts other cells

Significance • As a new approach in regenerative medicine • Helpful to improve our understanding of normal developmental biology • Helpful to identify transcription factors that induce cells to differentiate

Significance • As a new approach in regenerative medicine -- creating living, functional tissues to repair or replace tissue or organ function lost due to age, disease, damage, or congenital defects • Helpful to improve our understanding of normal developmental biology -- To treat e.g：Neurodegenerative diseases cardiac injury diabetes genetic disorder blood diseases…… • Helpful to identify transcription factors that induce cells to differentiate --cells e.g: Natural stem cells iPSC Trans-D cells

Good :-- self renewal --pluripotency --can be genetically modified --No immune attack Bad : --Time-consuming --Expensive --Low induction efficiency --risk of tumor forming Good : -- easier and faster -- Low cost -- Less likely to form tumors -- High efficiency -- No immune attack Bad: --No self renewal --No genetic modification --may not fully convert

Significance • As a new approach in regenerative medicine -- creating living, functional tissues to repair or replace tissue or organ function lost due to age, disease, damage, or congenital defects • Helpful to improve our understanding of normal developmental biology -- To treat e.g：Nerve degenerative diseases cardiac injury diabetes genetic disorder blood diseases • Helpful to identify transcription factors that induce cells to differentiate --cells e.g: Natural stem cells iPSC Trans-D cells

Significance • As a new approach in regenerative medicine • Helpful to improve our understanding of normal developmental biology • Helpful to identify transcription factors that induce cells to differentiate

That is all for today! Thank you!

Welcome Everyone