OBJECTIVE—Accumulation of glomerular matrix proteins is central to the pathogenesis diabetic nephropathy, with resident mesangial cells (MCs) known upregulate protein synthesis in response high glucose. Because activation GTPase RhoA has been implicated upregulation, we studied its role induction fibronectin MCs and vivo nephropathy. RESEARCH DESIGN AND METHODS—Glucose (30 mmol/l)-induced RhoA/Rho-kinase, AP-1 activation, upregulation were assessed by immunoblotting, luciferase,...

Accumulation of glomerular matrix is a hallmark diabetic nephropathy. The serine/threonine kinase Akt mediates glucose-induced upregulation collagen I in mesangial cells through transactivation the EGF receptor (EGFR). In addition, renal tubular cells, secretion TGF-β requires phosphoinositide-3-OH kinase, suggesting possible role for modulation expression, but mechanisms activation and its involvement regulation are unknown. Here, primary high glucose induced AktS473 phosphorylation, which...

We previously showed that ADAM17 mediates high glucose-induced matrix production by kidney mesangial cells. expression is increased in diabetic kidneys, suggesting its up-regulation may augment glucose profibrotic responses. thus studied the effects of on gene regulation. Primary rat cells were treated with (30 mm) or mannitol as osmotic control. High dose-dependently promoter activity, transcript, and protein levels. This correlated augmented activity after 24 h versus 1 glucose. tested...

Angiotensin II is an important mediator of CKD diverse etiology. A common pathologic feature glomerular fibrosis, a central which the profibrotic cytokine TGF- β . The mechanisms underlying induction and matrix by angiotensin are not completely understood. Recent studies showed that overexpression transcription factor SREBP-1 induces sclerosis can activate in tubular cells. We thus studied whether activated mediates II–induced profibrogenic responses primary rat mesangial Treatment cells...

Glomerular matrix accumulation is a hallmark of diabetic nephropathy. Recent studies showed that overexpression the transcription factor sterol-responsive element-binding protein (SREBP)-1 induces pathology reminiscent nephropathy, and SREBP-1 upregulation was observed in kidneys. We thus studied whether activated by high glucose (HG) mediates its profibrogenic responses. In primary rat mesangial cells, HG 30 min, seen appearance cleaved nuclear form (nSREBP-1), EMSA, activation an response...

Hypertension is a risk factor for chronic kidney disease, particularly when associated with impaired renal autoregulation and thereby increased intraglomerular pressure (Pgc). Elevated Pgc can be modeled in vitro by exposing glomerular mesangial cells to mechanical strain. We previously showed that RhoA mediates strain-induced matrix production. Here, we show activation dependent on an intact microtubule network. Upregulation of the profibrotic cytokine connective tissue growth (CTGF) strain...

Glomerular matrix accumulation is a hallmark of diabetic nephropathy. Recent studies showed that overexpression the transcription factor SREBP-1 induces glomerulosclerosis. TGFβ1 key profibrotic mediator glomerulosclerosis, but whether regulates its effects unknown. In kidney mesangial cells and in vivo, activates SREBP-1. This requires SCAP, S1P, PI3K/Akt signaling, independent Smad3. Activation TGFβ1-responsive reporter plasmid p3TP-lux SREBP-1a, not SREBP-1c, binding to an E-box adjacent...

Aims: Interventions to inhibit oxidative stress and apoptosis, important pathogenic contributors toward the progression of chronic kidney disease (CKD), are not well established. Here, we investigated role a transforming growth factor beta (TGFβ) superfamily neutralizing protein, follistatin (FST), in regulation apoptosis glomerular mesangial cells (MCs) CKD. Results: The endoplasmic reticulum (ER) inducer thapsigargin (Tg), known cause MC led post-translational increase expression FST....

Glomerular matrix accumulation is a hallmark of diabetic nephropathy. We showed that transactivation the epidermal growth factor receptor (EGFR) an important mediator upregulation in mesangial cells (MC) response to high glucose (HG). Here, we study mechanism EGFR transactivation. In primary MC, by 1 h HG (30 mM) was unaffected inhibitors protein kinase C, reactive oxygen species, or angiotensin II AT1 receptor. However, general metalloprotease inhibition, as well specific heparin-binding...

Glomerular matrix accumulation is a hallmark of diabetic nephropathy. We previously showed that RhoA activation by high glucose in mesangial cells (MC) leads to upregulation (Peng F, Wu D, Gao B, Ingram AJ, Zhang Chorneyko K, McKenzie R, Krepinsky JC. Diabetes 57: 1683-1692, 2008). Here, we study the mechanism whereby activated. In primary rat MC, required entry and metabolism. Broad PKC inhibitors (PMA, bisindolylmaleimide, Gö6976), as well specific PKCβ blockade with an inhibitor small...

Glomerular matrix accumulation is a hallmark of diabetic nephropathy. We have recently shown that epidermal growth factor receptor (EGFR) transactivation mediates high glucose (HG)-induced collagen I upregulation through PI3K-PKCbeta1-Akt signaling in mesangial cells (MC). Phospholipase Cgamma1 (PLCgamma1) interacts with activated receptors and activates classic PKC isoforms. thus studied its role HG-induced MC. Primary rat MC were treated HG (30 mM) or mannitol as osmotic control. Protein...

We previously showed that caveolin-1 (cav-1), an integral membrane protein, is required for the synthesis of matrix proteins by glomerular mesangial cells (MC). In a previous study to understand how cav-1 involved in regulating production, we had identified significant upregulation antifibrotic protein follistatin knockout MC. Follistatin inhibits profibrotic effects several members transforming growth factor beta superfamily, particular activins. Here, characterize molecular mechanism...

Tubulointerstitial fibrosis is a major feature associated with declining kidney function in chronic disease of diverse etiology. No effective means as yet exists to prevent the progression fibrosis. We have shown that transcription factor sterol-regulatory element-binding protein 1 (SREBP-1) an important mediator profibrotic response transforming growth factor-β (TGF-β) and angiotensin II, both key cytokines fibrotic process. Here, we examined role SREBP renal interstitial unilateral...

Increased intraglomerular pressure is an important pathogenic determinant of kidney fibrosis in the progression chronic disease, and can be modeled by exposing glomerular mesangial cells (MC) to mechanical stretch. MC produce extracellular matrix profibrotic cytokines, including connective tissue growth factor (CTGF) when stretched. We show that p21-activated kinase 1 (Pak1) activated stretch culture vivo a process marked elevated pressures. Its activation essential for CTGF upregulation....

ABSTRACT Glomerular matrix accumulation is the hallmark of diabetic nephropathy. The metalloprotease ADAM17 mediates high glucose (HG)-induced production by kidney mesangial cells through release ligands for epidermal growth factor receptor. Here, we study mechanism which HG activates ADAM17. We find that C-terminus essential activation and profibrotic response to HG. In C-terminus, Src-mediated Y702 phosphorylation PI3K–MEK–Erk-mediated T735 are crucial activation, both also required...

TGFβ1 is a major profibrotic mediator in chronic kidney disease (CKD). Its direct inhibition, however, limited by adverse effects. Inhibition of activins, also members the TGFβ superfamily, blocks effects, but mechanism underlying this and specific activin(s) involved are unknown.Cells were treated with or activins A/B. Activins inhibited generally follistatin, specifically neutralizing antibodies type I receptor downregulation. Cytokine levels, signaling responses assessed ELISA,...

Sterol regulatory element binding protein (SREBP) is an important potential mediator of kidney fibrosis and known to be upregulated in diabetic nephropathy. We evaluated the effectiveness SREBP inhibition as treatment Type 1 diabetes was induced uninephrectomized male CD1 mice with streptozotocin. The were treated inhibitor fatostatin for 12 weeks. At endpoint, function pathologic findings assessed. Fatostatin inhibited increase both isoforms (types 2) kidneys. Treatment attenuated basement...