Stem Cell bio one week of notes 3/28
Stem Cell bio one week of notes 3/28 3260
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This 4 page Class Notes was uploaded by AnnaCiara on Saturday April 2, 2016. The Class Notes belongs to 3260 at University of Connecticut taught by Dr. Conover in Spring 2016. Since its upload, it has received 17 views. For similar materials see Stem Cell Biology in Physiology at University of Connecticut.
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Date Created: 04/02/16
PNB 3260 Stem cell week of notes 3/29 and 3/31 Hematopoietic Hierarchy Definition: Hematopoietic stem cells (HSCs) are stem cells which give rise to blood cells via the process of hematopoiesis. HSCs generate both myeloid and lymphoid lineages: o Myeloid: neutrophils, basophils, eosinophils, erythrocytes, platelets o Lymphoid: T cells, B cells ▯ ▯ Characteristics of HSCs Multi-potency & Self-renewal Heterogeneous populations Cellular markers: many markers to identify HSCs and their progeny o Cluster of differentiation (CD34+, CD38+) o Receptor for stem cell factor (C-kit +) o Negative for markers of lineage commitment (lin - ) o ▯ Hematopoiesis during development Major sites of blood cell formation o Extra-embryonic yolk sac o Fetal liver o Bone marrow—only at late developmental stages In adults, mostly in bone marrow Why this switch during the course of development? o Ligation of umbilical cord causes major changes in blood flow. Loss of Nestin+ pericytes and disruption of HSC niche in fetal liver Niche is driven into adult bone marrow o ▯ Hematopoietic stem cell niche In adults, HSCs can be found mostly in bone marrow, small amounts in peripheral blood HSCs in dif locations in bone marrow receive dif signals o Osteoblasts, nestin expressing cells, and CXCL12-abundant reticular (CAR) cells promote HSC retention. o Adipocytes reduce HSC numbers o ▯ Homing Mobilization: HSCs migrate from blood to peripheral tissues Homing: HSCs migrate back to bone marrow Mirror processes regulated by chemokines, cytokines o Ex: stromal-derived factor- 1 (SDF-1), granulocyte– colony-stimulating factor (G-CSF), stem cell factor (SCF) o Exact mechanisms still unknown o ▯ ID of SCs Fluorescent tags attached to cell surface receptor can serve as a marker to identify ▯ Fluroescent Activated Cell Sorting (FACS) Start wiith a heterogenous pop of dif cell types Want to isolate CD34+ cells Cells driven under pressure in single-cell droplets ▯ ▯ Parabiosis Parabiosis-surgically joined together, shared circulation Ubiquitous GFP expressing mouse paired with WT Blood chimerism can be detected by looking for GFP+ cells in WT after separation 2 weeks young blood reverses age-related impairments in cognitive function and synaptic plasticity in mice ▯ HSCs transplantation Bone marrow harvest-drawing bone marrow out directly by puncturing a bone (usually hipbone) with a syringe o Painful!! How else could we get HSCs for transplantation? Peripheral blood-inject patient with cytokine, G-CSF, a few days before the harvest o so the SCs leave niche o G-CSF coaxes HSCs out of bone marrow, into peripheral blood o Filtering system that sorts out CD34+ cells and return blood cells back to patient ▯ Bone Marrow Transplantation in research Direct engraftment into encephalon Partial direct engraftment via blood vessels Substitution of recipient’s bone marrow Potential method: intranasal administration- nose is closer to brain Ablation vs no ablation of bone marrow o Radiation is dangerous but could promote development of new things from destruction Effects of radiation? Positive and negative ▯ Vasculature is an essential component of many adult stem cell niches ▯ ▯ Sleep disruption impairs hematopoietic stem cell transplantation in mice Rolls article In mice, donor sleep deprivation reduces the ability of HSCs to engraft and reconstitute blood and bone marrow of irradiated recipient by 50%! Down-regulated expression of miR-19b, a negative regulator of suppressor of cytokine signaling (SOCs) genes Inhibit migration and homing of HSCs Analyse percent chimerism Chimerism in PB and BM after 8 and 16 weeks Short-term vs long-term effects Efficiency of sleep-dep protocol (EEG, EMG) Corticosterone levels for stress BM isolated and lin-, c-kit +, Sca-1+, CD34 – (bc we’re in mice), CD150 + cells separated (HSCs) ▯ Assessmetn of homing potential ▯ GFP+ donor mice & WT recipient mice ▯ ▯ Comparative analysis of expression levels Downregulation of miR-19b SOCS3 (previously implicated in HSC migration) thought to be target of miR-19b Validation of interaction between miR-19b and SOCS3 Growth hormone (GH) affects miR-19b expression and migration GH secreted during sleep o GH increase attenuated in sleep dep. Mice GH causes increased miR-19b expression GH dose-dependent affect on HSC migration Recovery sleep: imp for this experiment and in daily life Sleep dep article is very very important Final review Monday 5-7 tls 111