Angiotensin II stimulates fibronectin protein synthesis via a Gβγ/arachidonic acid-dependent pathway

Abstract

Alexander LD, Ding Y, Alagarsamy S, Cui X. Angiotensin II stimulates fibronectin protein synthesis via a G␤␥/arachidonic aciddependent pathway. Am J Physiol Renal Physiol 307: F287-F302, 2014. First published June 11, 2014 doi:10.1152/ajprenal.00094.2014.-In rabbit proximal tubular cells, ANG II type 2-receptor (AT 2 )-induced arachidonic acid release is PLA 2 coupled and dependent of G protein ␤␥ (G␤␥) subunits. Moreover, ANG II activates ERK1/2 and transactivates EGFR via a c-Src-dependent mechanism. Arachidonic acid has been shown to mimic this effect, at least in part, by an undetermined mechanism. In this study, we determined the effects of ANG II on fibronectin expression in cultured rabbit proximal tubule cells and elucidated the signaling pathways associated with such expression. We found that ANG II and transfection of G␤␥ subunits directly increased fibronectin protein expression, and this increase was inhibited by overexpression of ␤-adrenergic receptor kinase (␤ARK)-ct or DN-Src. Moreover, ANG II-induced fibronectin protein expression was significantly abrogated by the AT2 receptor antagonist PD123319. In addition, inhibition of cystolic PLA 2 diminished ANG II-induced fibronectin expression. Endogenous arachidonic acid mimicked ANG II-induced fibronectin expression. We also found that overexpression of G␤␥ subunits induced c-Src, ERK1/2, and EGFR tyrosine phosphorylation, which can be inhibited by overexpression of ␤ARK-ct or DN-Src. G␤␥ also induced c-Src SH2 domain association with the EGFR. Supporting these findings, in rabbit proximal tubular epithelium, immunoblot analysis indicated that ␤␥ expression was significant. Interestingly, arachidonic acid-and eicosatetraenoic acid-induced responses were preserved in the presence of ␤ARK-ct. This is the first report demonstrating the regulation of EGFR, ERK1/2, c-Src, and fibronectin by G␤␥ subunits in renal epithelial cells. Moreover, this work demonstrates a role for G␤␥ heterotrimeric proteins in ANG II, but not arachidonic acid, signaling in renal epithelial cells. arachidonic acid; angiotensin II; c-Src, epidermal growth factor receptor transactivation; carboxyl terminus of ␤-adrenergic receptor kinase-1; mitogen-activated protein kinase; G␤␥

Cyclic stretch-induced TGF-β1 and fibronectin expression is mediated by β1-integrin through c-Src- and STAT3-dependent pathways in renal epithelial cells

“…These results show that STAT3 is involved in stretch-induced fibronectin and TGF-␤1 expression and that stretch-stimulated fibronectin expression in HK-2 cells was mediated by TGF-␤1. (11,24,50) and fibronectin (2,59,60). Moreover, previous studies from this laboratory have shown that mechanical stretch activates c-Src in renal tubular cells (1).…”

“…Western blot analysis was carried out as previously described (1,2). Briefly, proteins were extracted with buffer containing 50 mM Tris, pH 7.2, 1% (vol/vol) Triton X-100, 1 mM Na 3VO4, 1 mM EGTA, 0.2 mM phenylmethanesulfonyl fluoride, 25 g/ml leupeptin, and 10 g/ml aprotinin.…”

Prostaglandin E2 transactivates the colony‐stimulating factor‐1 receptor and synergizes with colony‐stimulating factor‐1 in the induction of macrophage migrationviathe mitogen‐activated protein kinase ERK1/2

“…1 A ). It should be noted that these molecules were able to induce cellular signaling as witnessed by the activation of ERK1/2 (21). However, based on previous reports on the transactivation of EGFR, we cannot exclude that other arachidonic acid derivatives are able to induce CSF‐1R phosphorylation (22).…”

Aliskiren Attenuates the Inflammatory Response and Wound Healing Process in Diabetic Mice With Periodontal Disease

“…Fn1 expression, also an extracellular matrix glycoprotein related to tissue repair and cell adhesion/migration (Ren et al, 2013), was found to be significantly increased after PD in normal and diabetic mice, suggesting that its production is mediated by renin release. Recent studies have already shown that AngII stimulates Fn synthesis in proximal tubular (Alexander et al, 2014) and collecting duct cells (Cuevas et al, 2015) by different pathway. An important point is that wound healing process occurs in three phases: inflammation, proliferation, and remodeling.…”