Synergistic Effects of Pdgf-bb and Camp-elevating Agents on Expression of Connexin43 in Mesangial Cells.
From: Dept. of Molecular Signaling, Interdisciplinary Graduate School of Medicine and Engineering, Univ. of Yamanashi, Tamaho, Yamanashi 409-3898, Japan. yao@yamanashi.ac.jp
American journal of physiology. Renal physiology
- Publish Date: May 2006
- ISSN: 0363-6127
- Volume: 290
- Issue: 5
- Pages: F1083-93
- Medium: Print
- Language: English
- Citation (JAMA): Yao Jian, Kitamura Masanori, Zhu Ying, et al. Synergistic Effects of Pdgf-bb and Camp-elevating Agents on Expression of Connexin43 in Mesangial Cells.. Am. J. Physiol. Renal Physiol. May 2006;290:F1083-93
Abstract
The gap junction plays an important role in the regulation of cell growth, migration, and differentiation. Platelet-derived growth factor (PDGF) is reported to be a potent inhibitor of gap junctional intercellular communication (GJIC). Short-term exposure of cells to PDGF causes rapid and transient disruption of GJIC without altering connexin43 (Cx43) protein level. In this study, we investigated long-term effects of PDGF-BB on Cx43 expression in mesangial cells (MCs). Exposure of MCs to PDGF-BB affected neither the Cx43 protein level nor GJIC. However, in the presence of cAMP-elevating agents, PDGF-BB dramatically increased the expression of Cx43, which was accompanied by obviously augmented membrane distribution of Cx43 and functional GJIC. The increased expression of Cx43 was closely correlated with reduction in alpha-actin, a dedifferentiation marker of MCs. The effect of PDGF on Cx43 was largely prevented by inhibitors of phosphatidylinositol 3’-kinase or mitogen-activated protein kinase, but not by inhibition of protein kinase C. Exposure of MCs to PDGF-BB caused elevation in intracellular cAMP, and it was abolished by indomethacin, a cyclooxygenase inhibitor. However, indomethacin did not affect the synergistic effect. In addition, PDGF-BB also did not affect the degradation of Cx43. With the use of MCs transfected with a Cx43 promoter-luciferase vector, cooperative activation of Cx43 promoter by PDGF and cAMP was found. Together, our data reveal, for the first time, unexpected synergy between PDGF-BB and cAMP-elevating agents in the induction of Cx43 and MC differentiation. Regulation of GJIC could be an important mechanism via which PDGF modulates MC phenotypes.
Mesh Headings (Keywords): Animals, Cell Culture Techniques, Cell Differentiation, Cell Movement, Connexin 43, Cyclic AMP, Gap Junctions, Mesangial Cells, Phenotype, Platelet-Derived Growth Factor, Rats
Check for Full Text / PubMed Unique Identifier (PMID): 16263806
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