title: Myosin II activity regulates neurite outgrowth and guidance in response to chondroitin sulfate proteoglycans.
abstract: Chondroitin sulfate proteoglycans (CSPGs) are major components of the extracellular matrix in the CNS that inhibit axonal regeneration after CNS injury. Signaling pathways in neurons triggered by CSPGs are still largely unknown. In this study, using well-characterized in vitro assays for neurite outgrowth and neurite guidance, we demonstrate a major role for myosin II in the response of neurons to CSPGs. We found that the phosphorylation of myosin II regulatory light chains is increased by CSPGs. Specific inhibition of myosin II activity with blebbistatin allows growing neurites to cross onto CSPG-rich areas and increases the length of neurites of neurons growing on CSPGs. Using specific gene knockdown, we demonstrate selective roles for myosin IIA and IIB in these processes. Time lapse microscopy and immunocytochemistry demonstrated that CSPGs also inhibit cell adhesion and cell spreading. Inhibition of myosin II selectively accelerated neurite initiation without altering cell adhesion and spreading on CSPGs.
authors.affiliation: Developmental Neurobiology Section, Cell Biology and Physiology Center, National Heart, Lung, and Blood Institute, National Institutes of Health, Bethesda, Maryland, USA.
authors.forename: Panpan
authors.initials: P
authors.lastname: Yu
authors.forename: Lizzie Y
authors.initials: LY
authors.lastname: Santiago
authors.forename: Yasuhiro
authors.initials: Y
authors.lastname: Katagiri
authors.forename: Herbert M
authors.initials: HM
authors.lastname: Geller
mesh_terms: D000199:Actins / Q000235:genetics / Q000378:metabolism; D000704:Analysis of Variance; D000818:Animals; D000831:Animals, Newborn; D002448:Cell Adhesion / Q000187:drug effects; D002465:Cell Movement / Q000187:drug effects; D002478:Cells, Cultured; D002531:Cerebellum / Q000166:cytology; D011508:Chondroitin Sulfate Proteoglycans / Q000494:pharmacology*; D005786:Gene Expression Regulation / Q000187:drug effects; D006576:Heterocyclic Compounds, 4 or More Rings / Q000494:pharmacology; D008239:Lysine / Q000494:pharmacology; D051379:Mice; D008810:Mice, Inbred C57BL; D018994:Myosin Light Chains / Q000378:metabolism; D024462:Myosin Type II / Q000235:genetics / Q000378:metabolism*; D016501:Neurites / Q000187:drug effects* / Q000502:physiology; D009474:Neurons / Q000166:cytology* / Q000378:metabolism*; D010766:Phosphorylation / Q000187:drug effects; D012333:RNA, Messenger / Q000378:metabolism; D034741:RNA, Small Interfering / Q000378:metabolism; D014162:Transfection
chemical_list: D000199:Actins; D011508:Chondroitin Sulfate Proteoglycans; D006576:Heterocyclic Compounds, 4 or More Rings; D018994:Myosin Light Chains; D012333:RNA, Messenger; D034741:RNA, Small Interfering; C472645:blebbistatin; D024462:Myosin Type II; D008239:Lysine