Renal hypertrophy and extracellular matrix accumulation are early features of diabetic nephropathy. We investigated the role NAD(P)H oxidase Nox4 in generation reactive oxygen species (ROS), hypertrophy, fibronectin expression a rat model type 1 diabetes induced by streptozotocin. Phosphorothioated antisense (AS) or sense oligonucleotides for were administered 2 weeks with an osmotic minipump 72 h after streptozotocin treatment. protein was increased kidney cortex compared non-diabetic...

Oxidative stress is implicated in human diseases. Some of the oxidative pathways are harbored mitochondria. NAD(P)H oxidases have been identified not only phagocytic but also somatic cells. Nox4 most ubiquitous these and a major source reactive oxygen species (ROS) many cell types kidney tissue diabetic animals. We generated specific antibodies, found that localizes to (i) Immunoblot analysis cultured mesangial cells cortex revealed present crude mitochondria, mitochondria-enriched heavy...

TGF-β1 expression closely associates with activation and conversion of fibroblasts to a myofibroblast phenotype synthesis an alternatively spliced cellular fibronectin variant, Fn-ED-A. Reactive oxygen species (ROS), such as superoxide, which is product NAD(P)H oxidase, also promote the transition myofibroblasts, but whether these two pathways are interrelated unknown. Here, we examined role for oxidase–derived ROS in TGF-β1–induced rat kidney α-smooth muscle actin (α-SMA) <i>In vitro</i>,...

OBJECTIVE We investigated the role of cytochrome P450 4A family (CYP4A), its metabolites, and NADPH oxidases both in reactive oxygen species (ROS) production apoptosis podocytes exposed to high glucose OVE26 mice, a model type 1 diabetes. RESEARCH DESIGN AND METHODS Apoptosis, albuminuria, ROS generation, superoxide CYP4A Nox protein expression, mRNA levels were measured vitro vivo. RESULTS Exposure mouse resulted apoptosis, with approximately one-third cells being apoptotic by 72 h....

ANG II induces protein synthesis through the serine-threonine kinase Akt/protein B (PKB) in mesangial cells (MCs). The mechanism(s) of activation Akt/PKB particularly by G protein-coupled receptors, however, is not well characterized. We explored role small GTPase Rac1, a component phagocyte NADPH oxidase, and gp91 phox homologue Nox4/Renox this signaling pathway. causes rapid an effect abrogated phospholipase A 2 inhibition mimicked arachidonic acid (AA). Northern blot analysis revealed...

Diabetes and high glucose (HG) increase the generation of NADPH oxidase-derived reactive oxygen species induce apoptosis glomerular epithelial cells (podocytes). Loss podocytes contributes to albuminuria, a major risk factor for progression kidney disease. Here, we show that HG inactivates AMP-activated protein kinase (AMPK), up-regulates Nox4, enhances oxidase activity, induces podocyte apoptosis. Activation AMPK blocked HG-induced expression We also identified tumor suppressor p53 as...

Reactive oxygen species (ROS) generated by Nox NADPH oxidases may play a critical role in the pathogenesis of diabetic nephropathy (DN). The efficacy Nox1/Nox4 inhibitor GKT137831 on manifestations DN was studied OVE26 mice, model type 1 diabetes. Starting at 4–5 mo age, mice were treated with 10 or 40 mg/kg, once-a-day for 4 wk. At both doses, inhibited oxidase activity, superoxide generation, and hydrogen peroxide production renal cortex from without affecting Nox1 Nox4 protein expression....

BMP-2 (bone morphogenetic protein-2) promotes differentiation of osteoblast precursor cells to mature osteoblasts that form healthy bone. In the present study, we demonstrate a novel mechanism BMP-2-induced differentiation. The antioxidant NAC (N-acetyl-L-cysteine) and flavoprotein enzyme NAD(P)H oxidase inhibitor DPI (diphenyleneiodonium) prevented BMP-2-stimulated alkaline phosphatase expression mineralized bone nodule formation in mouse 2T3 pre-osteoblasts. elicited rapid generation ROS...

Podocyte apoptosis is a critical mechanism for excessive loss of urinary albumin that eventuates in kidney fibrosis. Pharmacological doses the mammalian target rapamycin (mTOR) inhibitor reduce albuminuria diabetes. We explored hypothesis mTOR mediates podocyte injury High glucose (HG) induces podocytes, inhibits AMP-activated protein kinase (AMPK) activation, inactivates tuberin, and activates mTOR. HG also increases levels Nox4 Nox1 NADPH oxidase activity. Inhibition by low-dose decreases...

Mesangial matrix accumulation is an early feature of glomerular pathology in diabetes. Oxidative stress plays a critical role hyperglycemia-induced injury. Here, we demonstrate that, mesangial cells (MCs), endothelial nitric oxide synthase (eNOS) uncoupled upon exposure to high glucose (HG), with enhanced generation reactive oxygen species (ROS) and decreased production oxide. Peroxynitrite mediates the effects HG on eNOS dysfunction. upregulates Nox4 protein, inhibition abrogates increase...

Oxidative stress contributes to diabetic cardiomyopathy. This study explored the role of NADPH oxidase Nox4 as a source reactive oxygen species (ROS) involved in development Phosphorothioated antisense (AS) or sense (S) oligonucleotides for were administered 2 wk rats made by streptozotocin. activity, ROS generation, and expression Nox4, but Nox1 Nox2, increased left ventricular tissue rats. Expression molecular markers hypertrophy myofibrosis including fibronectin, collagen, α-smooth muscle...

Podocyte injury, a major contributor to the pathogenesis of diabetic nephropathy, is caused at least in part by excessive generation reactive oxygen species (ROS). Overproduction superoxide NADPH oxidase isoform Nox4 plays an important role podocyte injury. The plant extract silymarin attributed antioxidant and antiproteinuric effects humans animal models nephropathy. We investigated effect silybin, active constituent silymarin, cultures mouse podocytes OVE26 mouse, model type 1 diabetes...

The small G proteins Rac1 and RhoA regulate actin cytoskeleton, cell shape, adhesion, migration, proliferation. Recent studies in our laboratory have shown that NADPH oxidase Nox4-derived ROS are involved transforming growth factor (TGF)-β1-induced rat kidney myofibroblast differentiation assessed by the acquisition of an α-smooth muscle (α-SMA) phenotype expression alternatively spliced fibronectin variant (Fn-EIIIA). essential signaling some Nox homologs, but their role as effectors Nox4...

Activation of glomerular mesangial cells (MCs) by angiotensin II (Ang II) leads to hypertrophy and extracellular matrix accumulation. Here, we demonstrate that, in MCs, Ang induces an increase PDK-1 (3-phosphoinositide-dependent protein kinase-1) kinase activity that required its phosphorylation on tyrosine 9 373/376. Introduction into the PDK-1, mutated these residues or kinase-inactive, attenuates II-induced fibronectin II-mediated activation (total 373/376) are inhibited transfected with...

Angiotensin II (Ang II) stimulates hypertrophy of glomerular mesangial cells. The signalling mechanism by which Ang exerts this effect is not precisely known. Downstream potential targets are the extracellular-signal-regulated kinases 1 and 2 (ERK1/ERK2). We demonstrate that activates ERK1/ERK2 via AT1 receptor. Arachidonic acid (AA) mimics action on phospholipase A2 inhibitors blocked II-induced activation. antioxidant N-acetylcysteine as well NAD(P)H oxidase diphenylene iodonium...

OBJECTIVE—To investigate potential mechanisms of oxidative DNA damage in a rat model type 1 diabetes and murine proximal tubular epithelial cells primary culture cells. RESEARCH DESIGN AND METHODS—Phosphorylation Akt tuberin, 8-oxo-7,8-dihydro-2′-deoxyguanosine (8-oxodG) levels, 8-oxoG-DNA glycosylase (OGG1) expression were measured kidney cortical tissue control diabetic animals incubated with normal or high glucose. RESULTS—In the renal cortex rats, increase phosphorylation is associated...

Biallelic inactivation of the von Hippel-Lindau tumor suppressor gene (VHL) is linked to development hereditary and sporadic renal cell carcinoma (RCC). In absence VHL, α subunits heterodimeric hypoxia-inducible transcription factors (HIF-1α HIF-2α) are stabilized. Reactive oxygen species, generated by NAD(P)H oxidases, involved in signaling cascades malignant growth. We show that VHL-deficient cells p22phox, Nox4 protein levels NADPH-dependent superoxide generation increased. Reintroduction...

Background Inflammatory cytokines are detected in the plasma of patients with renal cell carcinoma (RCC) and associated poor prognosis. However, primary type involved producing inflammatory biological significance RCC remain unknown. Inflammation is oxidative stress, upregulation hypoxia inducible factor 1-alpha, production pro-inflammatory gene products. Solid tumors often heterogeneous oxygen tension together suggesting that may play a role processes RCC. Epithelial cells have been...