Browsing by Author "Cortés, V."

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    Adenovirus-mediated hepatic syndecan-1 overexpression induces hepatocyte proliferation and hyperlipidaemia in mice
    (2007) Cortés, V.; Zanlungo Matsuhiro, Silvana; Brandan, Enrique; Rigotti Rivera, Attilio
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    Decreased caveolae in AGPAT2 lacking adipocytes is independent of changes in cholesterol or sphingolipid levels: A whole cell and plasma membrane lipidomic analysis of adipogenesis
    (2021) González-Hódar, L.; McDonald, J.G.; Vale, G.; Thompson, B.M.; Figueroa, A.-M.; Tapia, P.J.; Robledo, F.; Agarwal, A.K.; Garg, A.; Horton, J.D.; Cortés, V.
    Background Adipocytes from lipodystrophic Agpat2−/− mice have impaired adipogenesis and fewer caveolae. Herein, we examined whether these defects are associated with changes in lipid composition or abnormal levels of caveolae-associated proteins. Lipidome changes were quantified in differentiated Agpat2−/− adipocytes to identify lipids with potential adipogenic roles. Methods Agpat2−/− and wild type brown preadipocytes were differentiated in vitro. Plasma membrane was purified by ultracentrifugation. Number of caveolae and caveolae-associated proteins, as well as sterol, sphingolipid, and phospholipid lipidome were determined across differentiation. Results Differentiated Agpat2−/− adipocytes had decreased caveolae number but conserved insulin signaling. Caveolin-1 and cavin-1 levels were equivalent between Agpat2−/− and wild type adipocytes. No differences in PM cholesterol and sphingolipids abundance were detected between genotypes. Levels of phosphatidylserine at day 10 of differentiation were increased in Agpat2−/− adipocytes. Wild type adipocytes had increased whole cell triglyceride, diacylglycerol, phosphatidylglycerol, phosphatidic acid, lysophosphatidylcholine, lysophosphatidylethanolamine, and trihexosyl ceramide, and decreased 24,25-dihydrolanosterol and sitosterol, as a result of adipogenic differentiation. By contrast, adipogenesis did not modify whole cell neutral lipids but increased lysophosphatidylcholine, sphingomyelin, and trihexosyl ceramide levels in Agpat2−/− adipocytes. Unexpectedly, adipogenesis decreased PM levels of main phospholipids in both genotypes. Conclusion In Agpat2−/− adipocytes, decreased caveolae is not associated with changes in PM cholesterol nor sphingolipid levels; however, increased PM phosphatidylserine content may be implicated. Abnormal lipid composition is associated with the adipogenic abnormalities of Agpat2 −/− adipocytes but does not prevent insulin signaling.
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    Differentiation and Imaging of Brown Adipocytes from the Stromal Vascular Fraction of Interscapular Adipose Tissue from Newborn Mice
    (2023) Figueroa, A.-M.; Stolzenbach, F.; Tapia, P.; Cortés, V.
    Brown adipose tissue (BAT) is only present in mammals and has a thermogenic function. Brown adipocytes are characterized by a multilocular cytoplasm with multiple lipid droplets, a central nucleus, a high mitochondrial content, and the expression of uncoupling protein 1 (UCP1). BAT has been proposed as a potential therapeutic target for obesity and its associated metabolic disorders due to its ability to dissipate metabolic energy as heat. To investigate BAT function and regulation, brown adipocyte culturing is indispensable. The present protocol optimizes tissue processing and cell differentiation for culturing brown adipocytes from newborn mice. Additionally, procedures for the imaging of differentiated adipocytes with both confocal immunofluorescence and transmission electron microscopy are shown. In the brown adipocytes differentiated with the techniques described herein, the major defining features of classical BAT are preserved, including high UCP1 levels, increased mitochondrial mass, and very close physical contact between the lipid droplets and mitochondria, making this method a valuable tool for BAT studies.
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    Prolonged Activation of the Htr2b Serotonin Receptor Impairs Glucose Stimulated Insulin Secretion and Mitochondrial Function in MIN6 Cells
    (2017) Cataldo Bascuñan, Luis Rodrigo; Mizgier Rojas, María Luisa; Bravo Sagua, Roberto; Jaña, Fabián; Cárdenas, César; Llanos, Paola; Busso, Dolores; Olmos Coelho, Pablo Roberto; Galgani Fuentes, José; Santos Martín, José Luis; Cortés, V.