title: Involvement of mesangial cells expressing alpha-smooth muscle actin during restorative glomerular remodeling in Thy-1.1 nephritis.
abstract: The function of actin cytoskeleton in mesangial cells (MCs) during the recovering process of injured glomeruli is not fully understood. MCs in injured glomeruli express alpha-smooth muscle actin (alpha-SMA), which is not detected in normal glomeruli. We focused on the localization of alpha-SMA in MCs of Thy-1.1 nephritic rat. Expression of alpha-SMA in the injured glomeruli peaked at day 5 after antibody injection and then declined gradually. At day 5, MCs, where alpha-SMA was localized at their cytoplasmic processes situated in various positions, occupied the expanded mesangium. MCs expressing alpha-SMA tended to be located at the peripheral region close to the glomerular basement membrane (GBM) or endothelial cells at day 8. Localization of alpha-SMA within the peripheral MCs was restricted to the cytoplasmic processes radiating toward the GBM and touching it with their tips at day 8. These alpha-SMA-containing processes are suitable to transmit the contractile force to GBM and may contribute to normalize the expanded glomerular volume. In addition, an actin-binding protein, drebrin, was localized in all MC processes extending toward various directions throughout the course of nephritis, suggesting that drebrin is involved in the formation of MC processes.
authors.affiliation: Department of Anatomy, Juntendo University School of Medicine, 2-1-1 Hongo, Bunkyo-ku, Tokyo 113-8421, Japan. hidetake@med.juntendo.ac.jp
authors.forename: Koichiro
authors.initials: K
authors.lastname: Ichimura
authors.forename: Hidetake
authors.initials: H
authors.lastname: Kurihara
authors.forename: Tatsuo
authors.initials: T
authors.lastname: Sakai
mesh_terms: D000199:Actins / Q000096:biosynthesis*; D000818:Animals; D002196:Capillaries / Q000378:metabolism; D007678:Kidney Glomerulus / Q000098:blood supply / Q000378:metabolism / Q000473:pathology*; D008297:Male; D050527:Mesangial Cells / Q000378:metabolism / Q000502:physiology; D018613:Microscopy, Confocal; D009130:Muscle, Smooth / Q000378:metabolism; D009393:Nephritis / Q000276:immunology / Q000378:metabolism / Q000473:pathology*; D009479:Neuropeptides / Q000378:metabolism; D051381:Rats; D017208:Rats, Wistar; D018800:Thy-1 Antigens / Q000276:immunology*
chemical_list: D000199:Actins; D009479:Neuropeptides; D018800:Thy-1 Antigens; C053386:drebrins