title: ENaC proteins contribute to VSMC migration.
abstract: Vascular smooth muscle cell (VSMC) migration plays a key role in tissue repair after arterial wall injury. VSMC migration requires integration of chemical and mechanical signaling mechanisms. Recently, we showed that epithelial Na(+) channel (ENaC) proteins are expressed in VSMCs and that ENaC inhibition abolishes pressure-induced constriction in isolated artery segments. However, whether ENaC proteins play a role in VSMC migration is unknown. The goal of this study was to determine whether ENaC molecules are required for VSMC migration. Using RT-PCR, immunoblotting, and immunolabeling, we detected expression of alpha-, beta-, and gammaENaC transcripts and proteins in cultured VSMCs (SV40-LT and A10 cells). Of the three proteins, betaENaC was the most readily detected in both cell lines by immunolocalization and Western blotting. Inhibition of ENaC activity with 1 microM benzamil blunted VSMC migration associated with wound healing (40.3% at 8 h and 26.2% at 24 h) and in response to the chemotactic stimulant platelet-derived growth factor-BB (38.1%). Furthermore, silencing ENaC gene expression with small interfering RNA blunted VSMC migration. These data indicate that expression of ENaC proteins is required for normal VSMC migration and suggest a potential new role for ENaC proteins in vascular tissue repair.
authors.affiliation: Dept. of Physiology and Biophysics, University of Mississippi Medical Center, Jackson, MS 39216, USA.
authors.forename: Samira C
authors.initials: SC
authors.lastname: Grifoni
authors.forename: Kimberly P
authors.initials: KP
authors.lastname: Gannon
authors.forename: David E
authors.initials: DE
authors.lastname: Stec
authors.forename: Heather A
authors.initials: HA
authors.lastname: Drummond
mesh_terms: D000584:Amiloride / Q000031:analogs & derivatives / Q000494:pharmacology; D000818:Animals; D002460:Cell Line; D002465:Cell Movement / Q000502:physiology*; D053503:Epithelial Sodium Channels / Q000378:metabolism*; D005786:Gene Expression Regulation; D020868:Gene Silencing; D009131:Muscle, Smooth, Vascular / Q000166:cytology / Q000187:drug effects / Q000378:metabolism*; D034741:RNA, Small Interfering / Q000235:genetics / Q000378:metabolism; D051381:Rats; D014945:Wound Healing / Q000502:physiology
chemical_list: D053503:Epithelial Sodium Channels; D034741:RNA, Small Interfering; C013407:benzamil; D000584:Amiloride