ATP-diphosphohydrolase activity in rat renal microvillar membranes and vascular tissue

Artículo de publicación ISIEcto-nucleotidases may have a role in the regulation of purinoceptor-mediated responses. ATP-diphosphohydrolase or apyrase has been described as an ecto-nucleotidase, which is characterized by a low specificity for its substrates and bivalent cations, The aim of this work was to demonstrate the presence of apyrase as an ecto-enzyme in the rat kidney, ATPase-ADPase activities of the renal microvillar membrane preparation, which correspond to 'right side out' membranes, were characterized, The detection of ATP-diphosphohydrolase in the renal vasculature was done through perfusion of isolated rat kidney, ATPase-ADPase activities of the microvillar membrane preparation and apyrase share similar kinetic properties, These include: low substrate and bivalent metal specificities and insensitivity towards inhibitors like: oligomycin, ouabain, verapamil, levamisole and Ap(5)A. The M(r) of native ATPase and ADPase activities,vas determined by the Co-60 irradiation-inactivation technique being around 65 kDa for both hydrolytic activities, Immunowestern blot analysis also supports the presence of apyrase in microvilli, Perfusion of isolated rat kidney with ATP and ADP, in the presence or absence of different inhibitors or apyrase antibodies indicated the existence of this enzyme in the vascular endothelium. The identification of ATP-diphosphohydrolase as an ecto-enzyme both in microvilli and vasculature support the proposal that the enzyme may have an important role in the extracellular metabolism of nucleotides

A polyphenol-rich Calafate (Berberis microphylla) extract rescues glucose tolerance in mice fed with cafeteria diet

The establishment of a chronic inflammatory state in the adipose tissue contributes to obesity-associated insulin resistance. Hence, disrupting the inflammatory response elicited by obesity remains a relevant target to tackle the modern-world pandemic. We evaluated the anti-inflammatory and insulin-sensitizing effect of Calafate (Berberis microphylla) by producing and characterizing a polyphenol-pure Calafate extract (PPCE). C57BL/6 mice fed with cafeteria diet for 14 weeks were administered PPCE (50 mg/Kg/day) for 4 weeks. PPCE administration rescued glucose tolerance and insulin-elicited AKT phosphorylation in white adipose tissue of diet-induced insulin-resistant mice. Furthermore, the cafeteria diet-induced expression of TNF-alpha and F4/80 was attenuated by PPCE administration, suggesting that PPCE rescues insulin sensibility by ameliorating the obesity-associated inflammatory state. Altogether, our data shows that Calafate represents a natural source of polyphenols with glucose tolerance-improving properties in vivo, suggesting a potential use of PPCE as a complementary tool against insulin resistance.CONICYT Scholarship (Chile) 21120219 Comision Nacional de Investigacion Cientifica y Tecnologica (CONICYT) CONICYT FONDECYT 1111021

Erratum to: Guidelines for the use and interpretation of assays for monitoring autophagy (3rd edition) (Autophagy, 12, 1, 1-222, 10.1080/15548627.2015.1100356

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