title: Endocardial endothelial cells stimulate proliferation and collagen synthesis of cardiac fibroblasts.
abstract: Given that vascular endothelial cells play an important role in the modulation of vascular structure and function, we hypothesized that endocardial endothelial cells (EECs) may have a modulator role in regulating the cardiac interstitial cells. Endocardial endothelial cells were isolated from freshly collected pig hearts and cardiac fibroblasts were isolated from 3- to 4-d-old Wistar rats. Fibroblasts were cultured in the presence or absence of conditioned medium from EECs. Proliferation of cardiac fibroblasts was measured by the incorporation of [3H]- Thymidine and collagen synthesis was assayed by the incorporation of [3H]-Proline. To determine the involvement of signaling mediators, in separate experiments, cardiac fibroblasts were incubated with BQ123 (selective ETA receptor antagonist), PD142893 (nonselective ETA/ETB receptor antagonist), Bis-indolylmaleimide (PKC inhibitor), PD 098059 (MEK inhibitor), or neutralizing anti-transforming growth factor (TGF)-beta-antibody. Endocardial endothelium-derived factors endothelin (ET)-1, TGF-beta, and Angiotensin (Ang)-II in the conditioned medium were assayed by enzyme-linked immunosorbent assay using commercially available kits. We report here evidence that suggest that endocardial endothelial cells stimulate both proliferation and collagen synthesis of cardiac fibroblasts. The response seems to be mediated by endothelin through its ETA receptor. Our results also indicate that protein kinase C (PKC) and mitogen-activated protein kinase (MAPK) pathways are essential for the EEC-induced proliferation of cardiac fibroblasts.
authors.affiliation: Division of Cellular & Molecular Cardiology and Vivarium, Sree Chitra Tirunal Institute for Medical Sciences and Technology, Trivandrum - 695011, India.
authors.forename: Leena
authors.initials: L
authors.lastname: Kuruvilla
authors.forename: Renuka R
authors.initials: RR
authors.lastname: Nair
authors.forename: P R
authors.initials: PR
authors.lastname: Umashankar
authors.forename: Arthur Vijayan
authors.initials: AV
authors.lastname: Lal
authors.forename: Chandrasekharan Cheranellore
authors.initials: CC
authors.lastname: Kartha
mesh_terms: D000818:Animals; D002460:Cell Line; D049109:Cell Proliferation; D003094:Collagen / Q000378:metabolism*; D017077:Culture Media, Conditioned / Q000378:metabolism; D004699:Endocardium / Q000378:metabolism*; D042783:Endothelial Cells / Q000166:cytology* / Q000378:metabolism; D004730:Endothelium, Vascular / Q000378:metabolism*; D004791:Enzyme Inhibitors / Q000494:pharmacology; D005347:Fibroblasts / Q000378:metabolism; D009206:Myocardium / Q000378:metabolism*; D011493:Protein Kinase C / Q000378:metabolism; D051381:Rats; D017208:Rats, Wistar; D016212:Transforming Growth Factor beta / Q000378:metabolism
chemical_list: D017077:Culture Media, Conditioned; D004791:Enzyme Inhibitors; D016212:Transforming Growth Factor beta; D003094:Collagen; D011493:Protein Kinase C