title: Low molecular weight fibroblast growth factor-2 signals via protein kinase C and myofibrillar proteins to protect against postischemic cardiac dysfunction.
abstract: Among its many biological roles, fibroblast growth factor-2 (FGF2) acutely protects the heart from dysfunction associated with ischemia/reperfusion (I/R) injury. Our laboratory has demonstrated that this is due to the activity of the low molecular weight (LMW) isoform of FGF2 and that FGF2-mediated cardioprotection relies on the activity of protein kinase C (PKC); however, which PKC isoforms are responsible for LMW FGF2-mediated cardioprotection, and their downstream targets, remain to be elucidated. To identify the PKC pathway(s) that contributes to postischemic cardiac recovery by LMW FGF2, mouse hearts expressing only LMW FGF2 (HMWKO) were bred to mouse hearts not expressing PKCα (PKCαKO) or subjected to a selective PKCε inhibitor (εV(1-2)) before and during I/R. Hearts only expressing LMW FGF2 showed significantly improved postischemic recovery of cardiac function following I/R (P < 0.05), which was significantly abrogated in the absence of PKCα (P < 0.05) or presence of PKCε inhibition (P < 0.05). Hearts only expressing LMW FGF2 demonstrated differences in actomyosin ATPase activity as well as increases in the phosphorylation of troponin I and T during I/R compared with wild-type hearts; several of these effects were dependent on PKCα activity. This evidence indicates that both PKCα and PKCε play a role in LMW FGF2-mediated protection from cardiac dysfunction and that PKCα signaling to the contractile apparatus is a key step in the mechanism of LMW FGF2-mediated protection against myocardial dysfunction.
authors.affiliation: Department of Pharmacology and Cell Biophysics, University of Cincinnati College of Medicine, Cincinnati, OH 45267, USA.
authors.forename: Janet R
authors.initials: JR
authors.lastname: Manning
authors.forename: Sarah O
authors.initials: SO
authors.lastname: Perkins
authors.forename: Elizabeth A
authors.initials: EA
authors.lastname: Sinclair
authors.forename: Xiaoqian
authors.initials: X
authors.lastname: Gao
authors.forename: Yu
authors.initials: Y
authors.lastname: Zhang
authors.forename: Gilbert
authors.initials: G
authors.lastname: Newman
authors.forename: W Glen
authors.initials: WG
authors.lastname: Pyle
authors.forename: Jo El J
authors.initials: Jel J
authors.lastname: Schultz
mesh_terms: D000205:Actomyosin / Q000378:metabolism; D000818:Animals; D015153:Blotting, Western; D017301:Ca(2+) Mg(2+)-ATPase / Q000378:metabolism; D005260:Female; D016222:Fibroblast Growth Factor 2 / Q000235:genetics / Q000378:metabolism / Q000502:physiology*; D007770:L-Lactate Dehydrogenase / Q000378:metabolism; D008297:Male; D051379:Mice; D018345:Mice, Knockout; D008970:Molecular Weight; D009200:Myocardial Contraction / Q000502:physiology; D017202:Myocardial Ischemia / Q000188:drug therapy* / Q000503:physiopathology*; D015428:Myocardial Reperfusion Injury / Q000503:physiopathology; D009210:Myofibrils / Q000378:metabolism*; D010766:Phosphorylation / Q000502:physiology; D011493:Protein Kinase C / Q000502:physiology*; D017468:Receptors, Fibroblast Growth Factor / Q000378:metabolism; D019210:Troponin I / Q000378:metabolism; D020107:Troponin T / Q000378:metabolism
chemical_list: D017468:Receptors, Fibroblast Growth Factor; D019210:Troponin I; D020107:Troponin T; D016222:Fibroblast Growth Factor 2; D000205:Actomyosin; D007770:L-Lactate Dehydrogenase; D011493:Protein Kinase C; D017301:Ca(2+) Mg(2+)-ATPase
keywords: PKCα and ε; actomyosin ATPase; low molecular weight FGF2; postischemic cardiac function; troponin