StemCells

StemCells - 03.28.11 Stem Cell Biology Outline 1.What are...

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Unformatted text preview: 03.28.11 Stem Cell Biology Outline 1.What are stem cells? 2.Types of stem cells 3.Stem cells in disease and medicine Terminology Potency To9potent A measure of how many types of specialized cell a stem cell can make Can form en9re embryo Pluripotent Can form all lineages of the body, but not trophoblast cells Mul9potent Can make mul9ple types of cells of a par9cular lineage Unipotent Can make a single cell type What is a stem cell? 1. Stem cells are capable of dividing and renewing themselves over long periods 2. Stem cells are unspecialized 3. Stem cells give rise to >250 specialized cell types Why self-renew AND differentiate? 1 stem cell 1 stem cell Self renewal  ­ maintains the stem cell pool 4 specialized cells Differen9a9on  ­ replaces dead or damaged cells throughout your life Where are stem cells found? embryonic stem cells blastocyst  ­ a very early embryo adult stem cells fetus, baby and throughout life Stem cell potency becomes limited throughout development Types of stem cell: 1) Embryonic stem cells Embryonic stem (ES) cells are derived from embryonic inner cell mass ES may be generated by somatic cell nuclear transfer (SCNT) ES cells can be differentiated into different cell types in culture The same signals used during normal development: • Growth factors • Cytokines Once committed to differentiation, stem cells cannot self renew Types of stem cell: 2) Adult stem cells Adult stem cells: Where are they? surface of the eye skin tes8cles muscles brain breast intes8nes 1. Adult stem cells are found among differentiated cells in a tissue or organ that can renew itself 2. Primary function - maintain and repair tissue 3. Small number of adult stem cells in each tissue bone marrow Adult stem cells in the intestine Adult stem cells: Principles of renewing tissues Stem cell  ­  ­  ­  ­ stem cell: self renew divide rarely high potency rare  ­  ­  ­  ­ commiIed progenitors: “transient amplifying cells” mul8potent divide rapidly no self ­renewal  ­  ­ specialized cells: work no division Adult stem cells: Haematopoietic stem cells (HSCs) NK cell T cell B cell dendri8c cell megakaryocyte HSC platelets erythrocytes macrophage neutrophil bone marrow eosinophil basophil commiIed progenitors specialized cells Adult stem cells: Neural stem cells (NSCs) Neurons Interneurons Oligodendrocytes NSC Type 2 Astrocytes Type 1 Astrocytes brain commiIed progenitors specialized cells Adult stem cells: Gut stem cells (GSCs) Paneth cells Goblet cells GSC Endocrine cells Columnar cells Small intes8ne commiIed progenitors specialized cells Adult stem cells: Mesenchymal stem cells (MSCs) Bone (osteoblasts) Car8lage (chondrocytes) MSC bone marrow Fat (adipocytes) commiIed progenitors specialized cells Types of stem cell: 3)Induced pluripotent (iPS) stem cells Induced pluripotent stem cells (iPS cells) Advantage: no need for embryos! iPS cells are generated by expression of transcrip9on factors that promote stem cell iden9ty embryo: ES cells: From Mitsui et al (2003) Cell 113: 631-642 Induced pluripotent stem cells (iPS cells) gene8c reprogramming pluripotent stem cell (iPS) cell from the body (skin) differen8a8on How to stem cells reatain their “stemness”: Intrinsic vs. extrinsic factors Extrinsic factors: stem cell niches Niche Microenvironment around stem cells that provides support and signals regula8ng self ­renewal and differen8a8on Direct contact Soluble factors stem cell niche Intermediate cell The Wnt pathway stimulates stem cell proliferation in the intestine Intrinsic factors the Drosophila neuroblast Intrinsic factors the Drosophila neuroblast Stem cells and disease Stem cells: potential uses Stem cell muta9ons have been implicated in certain cancers Cancer stem cells can evade standard cancer treatments and may cause relapse Stem cell therapy holds promise !"#$%"&'($)*+,$,-./0$123./3.4for treatment of diabetes Stem Cell Research 101 Stem cell therapy holds promise for treatment of leukemia !"#$%&'%#%()*#$+*,$%-.#+/0*1 Stem Cell Research 101 Stem cell therapy for cardiac repair ...
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This note was uploaded on 05/26/2011 for the course BIO 205 taught by Professor Reed during the Spring '11 term at UNC.

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