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Sarcolemma in Health and Disease Noah Weisleder, Ph.D Sarcolemma in Health and Disease Noah Weisleder, Ph.D. Department of Physiology and Cell Biology Davis Heart and Lung Research Institute The Ohio State University [email protected] (614) 292‐5321 MNil d Bk Cll d Ti Rh2001 Sarcolemma is more than a cell membrane Quizlet.com • Lipid bilayer, integral proteins and associated basement membrane • Specialized adaptations for physiological requirements of • skeletal muscle fibers Kessel and Kardon. Tissues and Organs: a Text‐Atlas of Scanning Electron Microscopy. W.H.Freeman and Company, 1979 Specialized aspects of sarcolemma • Basement membrane • Electrical insulation • Neuromuscular junction • Link cytoskeleton to ECM • Endo‐ and Exocytosis • Propagation of action potential • Excitation/Contraction coupling • Ion flux (calcium, etc) • Barrier function – Sarcolemmal membrane repair http://www.e‐heart.org/pages/01_cardiac_structure/01_Cardiac_Structure_Molecular_Anatomy_004.htm Cummings, et al. Addison Wesley Longman Skeletal muscle fiber basement membrane • Extracellular matrix provides majority of the elastic properties of skeletal muscles to facilitate relaxation of muscle following contraction Bowman W. (1840) Philos. Trans. R. Soc. Lond. Biol. Sci. 130:457–494. Skeletal muscle fiber basement membrane Collagen IV Fibrillar lamina lamina Basal • Highly elastic extracellular matrix • Electrical insulation • Muscle and nerve generation and regeneration Allamand et al. Skeletal Muscle 2011 1:30 Specialized extracellular matrix at the neuromuscular junction acetylcholinesterase • Relevant to a number of neuromuscular disorders Sanes, J. Journal of Biological Chemistry, 278, 12601‐12604. (2003) Neuromuscular junction in skeletal muscle • Site of axon innervation into muscle fiber • Denervation a component of multiple diseases people.fmarion.edu/tbarbeau/physio_muscle_supplements.htm http://biology.clc.uc.edu/fankhauser/Labs/Anatomy_&_Physiology/A&P202/Nerve_Histology/ Linking cytoskeleton to the extracellular matrix Clark, et al. Annual Review of Cell and Developmental Biology Vol. 18: 637‐706 (2002) Sarcolemmal membrane as a site of endocytosis and exocytosis Steele, at al. J Physiol July 1, 2007 vol. 582no. 117‐26 Propagation of the action potential 2010 Pearson Education Excitation Contraction Coupling Sarcolemma Koeppen & Stanton. Berne and Levy Physiology, 6th edition (2005). Calcium influx through the sarcolemma Shinde, at al. Sci Signal. 2013 Mar 19;6(267):ra18. Calcium influx through the sarcolemma • Excess Ca2+ contributes to myocyte death • Multiple pathways contribute Dowling, et al. Biochem. J. (2004) 379 (479–488) Barrier function of the sarcolemma • Breakdown of the barrier function of the membrane following disruption can contribute to cell death Life Scicences Web Textbook CSLS/University of Tokyo Sarcolemmal membrane repair maintains barrier function Membrane disruption Ca2+ entry through the injury site Ca2+‐triggering vesicle exocytosis Vesicle fusion Patch formation; membrane resealing Nature Reviews Molecular Cell Biology 6, 499-505 (June 2005) Intracellular vesicles participate in membrane patching following damage McNeil and Baker, Cell and Tissue Research, 2001 Evidence of membrane resealing in living mammalian cells Li, et al. Hum. Mol. Genet. (15 May 2006)15 (10): 1610‐1622. Lovering, et al. AJP Cell April 2011 C803‐C813 Methods to measure membrane repair • Dye exclusion/entry into the cell – UV laser damage – Physical disruption of the membrane – Histological analysis of tissues (Evans blue, IgG entry) • Leak of a biomarker out of the cell – Creatine kinase – Troponins – Lactate dehydrogenase • Changes in membrane biophysical conditions Membrane repair is a conserved physiologic process in multiple tissues Cell wounding Principal cells Organ Type of mechanical force (proportion of Reference stressed cells involved) Aperiodic, highly variable Skeletal muscle cells McNeil and Khakee, Skeletal muscle Yes (3-20%) intensity: shear, stretch (myocytes) 1992 Cardiac muscle Cyclic: shear, stretch Cardiac myocytes Yes (25%) Clarke et al., 1995 Aperiodic, highly variable Epidermal cells, Skin intensity: shear, stretch, Yes (3-6%) McNeil and Ito, 1990 Fibroblasts, etc. compression Yes, epithelial Gastrointestinal Epithelial cells, smooth Cyclic: shear, stretch cells (% not McNeil and Ito, 1989 tract muscle cells measured) Yes, aortic Vascular Endothelial cells, Constant and cyclic:shear endothelial cells Yu and McNeil, 1992 (conducting) smooth muscle cells (6.5%) Alveolar cells (2- Epithelial cells, 30% in Respiratory Cyclic: stretch endotherlial cells, Gajic et al., 2003 mechanically smooth muscle cells ventilated lung) Aperiodic, highly variable Yes, hair cells (% Peripheral nervous Inner ear cells Mulroy et al., 1998 intensity: shear not measured) McNeil and Steinhardt, Annu Rev Cell Dev Biol. 2003 Necessity of membrane repair in eukaryotic cells Cellular insult Membrane Patch = Cell Survival MG53? drives membrane repair Cell Membrane Resealing mechanism is dependent on size of membrane disruption Increasing size of membrane disruption McNeil & Terasaki Nature Cell Biology 3, E124 - E129 (2001) Membrane tension is a key determinate of cell membrane resealing Steinhardt Annals of the New York Academy of Sciences Vol 1066 pages 152–165, March 2006 Evolution of fusion‐based resealing following development of endocytotic apparatus A C B D McNeil & Terasaki Nature Cell Biology 3, E124 - E129 (2001) Skeletal muscle displays a substantial amount of membrane resealing Cell wounding Principal cells Organ Type of mechanical force (proportion of Reference stressed cells involved) Aperiodic, highly variable Skeletal muscle cells McNeil and Khakee, Skeletal muscle Yes (3-20%) intensity: shear, stretch (myocytes) 1992 Cardiac muscle Cyclic: shear, stretch Cardiac myocytes Yes (25%) Clarke et al., 1995 Aperiodic, highly variable Epidermal cells, Skin intensity: shear, stretch, Yes (3-6%) McNeil and Ito, 1990 Fibroblasts, etc. compression Yes, epithelial Gastrointestinal Epithelial cells, smooth Cyclic: shear, stretch cells (% not McNeil and Ito, 1989 tract muscle cells measured) Yes, aortic Vascular Endothelial cells, Constant and cyclic:shear endothelial cells Yu and McNeil, 1992 (conducting) smooth muscle cells (6.5%) Alveolar cells (2- Epithelial cells, 30% in Respiratory Cyclic: stretch endotherlial cells, Gajic et al., 2003 mechanically smooth muscle cells ventilated lung) Aperiodic, highly variable Yes, hair cells (% Peripheral nervous Inner ear cells Mulroy et al., 1998 intensity: shear not measured) McNeil and Steinhardt, Annu Rev Cell Dev Biol. 2003 Contractile nature of skeletal muscles lead to extensive mechanical stress How do cells repair the plasma membrane at the molecular level? What are the pathologic consequences of defective membrane repair? Cellular mechanism are better understood than the molecular mechanisms McNeil & Kirchhausen Nature Reviews Molecular Cell Biology 6,499‐505 (June 2005) Dysferlin Originally determined to be a ferlin family protein that was known to be mutated in limb girdle muscular dystrophy (type 2B) and Myoshi myopathy patients, (Nat Genet. 1998 Sep;20(1):31‐6). McNeil & Kirchhausen Nature Reviews Molecular Cell Biology 6,499‐505 (June 2005) Muscular dystrophy and compromised membrane repair in dysferlin null mice Bansal ,et al. Nature 423, 168‐172 (May 2003) Dysferlin function in membrane repair is not clear Molecular function of dysferlin in membrane repair is still not clear. Does it act as A fusogen for vesicles? Direct effects on remodeling of membrane? A platform to assemble other factors? Nat Clin Pract Cardiovascular Med (June 2005) Annexin‐A5 assembled into two‐dimensional arrays promotes cell membrane repair Bouterm et al. Nature Communications 2, Article number: 270 doi:10.1038/ncomms1270 AHNAK and other proteins interact with dysferlin and modulate membrane repair capacity Multiple proteins have been shown to be important for the resealing of membranes, however the molecular function of these proteins is not clear. Huang, et al. March 2007 The FASEB Journal vol. 21 no. 3732‐742 Other dysferlin interacting proteins linked to membrane repair Wallace and McNally Annual Review of Physiology Vol. 71: 37‐57 (2009) Mitsugumin 53 (MG53) is a tripartite motif family protein linked to membrane trafficking during membrane repair 82 MG53 40 Cai et al. Nature Cell Biology (2007) MG53 knockout mice display myopathy and breakdown of plasma membrane integrity wt (3m) 50 µm mg53-/- (3m) mg53-/- (10m) wt mg53-/- 200 µm Cai et al. Nature Cell Biology (2007) MG53 is required for translocation of dysferlin to injury sites on the plasma membrane G Cai, Weisleder, et al. J Biol Chem. 2009 Jun 5;284(23):15894-902. MG53 also associated with dysferlin to facilitate membrane repair Han (2011) Skeletal Muscle Vol. 1 Issue 1 Proteins associated with vesicle fusion during endo/exocytosis are also involved in membrane repair Andrews Sci. STKE, 3 May 2005 Vol. 2005, Issue 282, p. pe19 Reorganization of the cytoskeleton and organelles is required for effective membrane repair Mellgren. J Biol Chem. 2010 November 19; 285(47): 36597–36607. Summary Sarcolemma mediates many aspects of cellular function, and loss of these responses contributes to myocyte death in various ways Membrane repair is a conserved physiologic process that allows resealing of larger membrane disruptions. Loss of membrane integrity can lead to cell death unless he membrane is repaired. Progressive loss of cells can lead to dysfunction of the tissue, in the case of skeletal muscle this can result in muscular dystrophy. Increasing number of genes are linked to the cell repair process, however the molecular mechanism of their function will be areas of future study. Sarcolemma in Health and Disease Noah Weisleder, Ph.D. Department of Physiology and Cell Biology Davis Heart and Lung Research Institute The Ohio State University [email protected] (614) 292‐5321 MNil d Bk Cll d Ti Rh2001.
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