BACKGROUND-Idiopathic membranous nephropathy, a common form of the nephrotic syndrome, is an antibody-mediated autoimmune glomerular disease. Serologic diagnosis has been elusive because the target antigen is unknown.

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SYNOPSIS Vascular injury and chronic arterial diseases result in exposure of vascular smooth muscle cells (VSMCs) to increased concentrations of growth factors. The mechanisms by which growth factors trigger VSMC phenotype transitions remain unclear. Because cellular reprogramming initiated by growth factors requires not only the induction of genes involved in cell proliferation but also the removal of contractile proteins, we hypothesized that autophagy is an essential modulator of VSMC phenotype. Treatment of VSMCs with platelet-derived growth factor (PDGF)-BB resulted in decreased expression of the contractile phenotype markers calponin and α-smooth muscle actin and upregulation of the synthetic phenotype markers osteopontin and vimentin. Autophagy, as assessed by LC3-II abundance, LC3 puncta formation and electron microscopy, was activated by PDGF exposure. Inhibition of autophagy with 3-methyladenine, spautin-1, or bafilomycin stabilized the contractile phenotype. In particular, spautin-1 led to a remarkable stabilization α-smooth muscle cell actin and calponin in PDGF-treated cells and prevented actin filament disorganization, diminished production of extracellular matrix and abrogated VSMC hyperproliferation and migration. Interestingly, treatment of cells with PDGF prevented protein damage and cell death due to exposure to the lipid peroxidation product, 4-hydroxynonenal. These results demonstrate a distinct form of autophagy induced by PDGF that is essential for attaining the synthetic phenotype and for survival under conditions of high oxidative stress found to occur in vascular lesions.

Background Cardiac hypertrophy and heart failure are associated with metabolic dysregulation and a state of chronic energy deficiency. Although several disparate changes in individual metabolic pathways have been described, there has been no global assessment of metabolomic changes in hypertrophic and failing hearts in vivo. Here, we investigated the impact of pressure overload and infarction on myocardial metabolism. Methods and Results Male C57BL/6J mice were subjected to transverse aortic constriction (TAC) or permanent coronary occlusion (myocardial infarction; MI). A combination of LC/MS/MS and GC/MS techniques was used to measure 288 metabolites in these hearts. Both TAC and MI were associated with profound changes in myocardial metabolism affecting up to 40% of all metabolites measured. Prominent changes in branched amino acids acids (BCAAs) were observed after 1 week of TAC and 5 days after MI. Changes in BCAAs after MI were associated with myocardial insulin resistance. Longer duration of TAC and MI led to a decrease in purines, acylcarnitines, fatty acids and several lysolipid and sphingolipid species, but a marked increase in pyrimidines as well as ascorbate, heme and other indices of oxidative stress. Cardiac remodeling and contractile dysfunction in hypertrophied hearts were associated also with large increases in myocardial, but not plasma, levels of the polyamines putrescine and spermidine as well as the collagen breakdown product prolylhydroxyproline. Conclusions These findings reveal extensive metabolic remodeling common to both hypertrophic and failing hearts that are indicative of extensive extracellular matrix remodeling, insulin resistance and perturbations in amino acid, lipid and nucleotide metabolism.

Rationale Endothelial dysfunction is a characteristic feature of diabetes and obesity in animal models and humans. Deficits in nitric oxide production by endothelial nitric oxide synthase (eNOS) are associated with insulin resistance, which is exacerbated by high fat diet. Nevertheless, the metabolic effects of increasing eNOS levels have not been studied. Objective The current study was designed to test whether overexpression of eNOS would prevent diet-induced obesity and insulin resistance. Methods and Results In db/db mice and in high fat-fed wild-type (WT) C57BL/6J mice, the abundance of eNOS protein in adipose tissue was decreased without significant changes in eNOS levels in skeletal muscle or aorta. Mice overexpressing eNOS (eNOS-TG mice) were resistant to diet-induced obesity and hyperinsulinemia, although systemic glucose intolerance remained largely unaffected. In comparison with WT mice, high fat-fed eNOS-TG mice displayed a higher metabolic rate and attenuated hypertrophy of white adipocytes. Overexpression of eNOS did not affect food consumption or diet-induced changes in plasma cholesterol or leptin levels, yet plasma triglycerides and fatty acids were decreased. Metabolomic analysis of adipose tissue indicated that eNOS overexpression primarily affected amino acid and lipid metabolism; subpathway analysis suggested changes in fatty acid oxidation. In agreement with these findings, adipose tissue from eNOS-TG mice showed higher levels of PPAR-α and PPAR–γ gene expression, elevated abundance of mitochondrial proteins, and a higher rate of oxygen consumption. Conclusions These findings demonstrate that increased eNOS activity prevents the obesogenic effects of high fat diet without affecting systemic insulin resistance, in part, by stimulating metabolic activity in adipose tissue.