Arginine vasopressin increases iNOS-NO system activity in cardiac fibroblasts through NF-kappaB activation and its relation with myocardial fibrosis.
Previous studies have shown that arginine vasopressin (AVP) promotes myocardial fibrosis (MF), whereas nitric oxide (NO) inhibits MF. Cardiac fibroblasts (CFs) are the main target cells of MF. However, the modulatory effect of AVP on NO production in CFs and the role of this effect in MF are still unknown. In the present study, CFs obtained from Sprague-Dawley rats were stimulated with or without AVP and pyrrolidine dithiocarbamate (PDTC), a specific inhibitor of nuclear factor kappa-B (NF-kappaB). NO production and NOS activity were detected with absorption spectrometry, inducible nitric oxide synthase (iNOS) protein with Western blot analysis, iNOS mRNA with real-time PCR, CF collagen synthesis with [(3)H]proline incorporation, and NF-kappaB activation with immunofluorescence staining and Western blot analysis. The results showed that AVP increased NO production in a dose- and time-dependent manner, with maximal effects at 10(-7) mol/l after 24-h stimulation. AVP also increased NOS activity, protein and mRNA levels of iNOS in a coincident manner. Furthermore, AVP also increased CF collagen synthesis in a dose- and time-dependent manner. In addition, it was found that NF-kappaB was activated by AVP, and that PDTC could inhibit NO production, NOS activity, protein and mRNA levels of iNOS stimulated by AVP in a dose-dependent manner. The inhibitory effects of PDTC on NF-kappaB translocation were coincident with the effects of PDTC on iNOS-NO system activity. It is suggested that AVP increases NO production via the regulation of iNOS gene expression, and the upregulation of iNOS gene expression stimulated by AVP is mediated through NF-kappaB activation. NO production induced by AVP may counteract the profibrotic effects of AVP, thus the development of MF perhaps depends on the balance between profibrotic AVP and antifibrotic NO effects on MF.
Fan
Yan-Hong
YH
Department of Cardiology, Xijing Hospital, The Fourth Military Medical University, 17 Changlexi Street, Xi'an 710032, PR China. fanyanhong016@163.com
Zhao
Lian-You
LY
Zheng
Qiang-Sun
QS
Dong
Hui
H
Wang
Hai-Chang
HC
Yang
Xue-Dong
XD
D000818:Animals; D001127:Arginine Vasopressin / Q000378:metabolism* / Q000494:pharmacology; D009202:Cardiomyopathies / Q000378:metabolism* / Q000503:physiopathology; D002478:Cells, Cultured; D003094:Collagen / Q000378:metabolism; D004195:Disease Models, Animal; D004305:Dose-Response Relationship, Drug; D004790:Enzyme Induction / Q000235:genetics; D004791:Enzyme Inhibitors / Q000494:pharmacology; D005347:Fibroblasts / Q000378:metabolism* / Q000473:pathology* / Q000648:ultrastructure; D005355:Fibrosis / Q000378:metabolism / Q000503:physiopathology; D005455:Fluorescent Antibody Technique; D015971:Gene Expression Regulation, Enzymologic; D066298:In Vitro Techniques; D009206:Myocardium / Q000166:cytology / Q000378:metabolism / Q000648:ultrastructure; D016328:NF-kappa B / Q000187:drug effects / Q000378:metabolism*; D009569:Nitric Oxide / Q000378:metabolism*; D052247:Nitric Oxide Synthase Type II / Q000235:genetics / Q000378:metabolism*; D011759:Pyrrolidines / Q000494:pharmacology; D012333:RNA, Messenger / Q000235:genetics; D051381:Rats; D017207:Rats, Sprague-Dawley; D013053:Spectrophotometry; D013859:Thiocarbamates / Q000494:pharmacology
D004791:Enzyme Inhibitors; D016328:NF-kappa B; D011759:Pyrrolidines; D012333:RNA, Messenger; D013859:Thiocarbamates; D001127:Arginine Vasopressin; C020972:pyrrolidine dithiocarbamic acid; D009569:Nitric Oxide; D003094:Collagen; D052247:Nitric Oxide Synthase Type II