SPARC, also known as osteonectin, is well known for its physiological roles in bone formation and tissue remodeling, as well as in cancer pathology; however, evidence regarding its function in adipocytes is lacking. The present study explored the physiological role of SPARC in cultured 3T3-L1 white and HIB1B brown adipocytes of murine cell lines. Treatment of recombinant SPARC upregulated the fat browning marker proteins and genes in white adipocytes and activated brown adipocytes. Conversely, knockdown of Sparc markedly reduced these genes and proteins in both cell lines. In addition, recombinant SPARC inhibited expression of adipogenic and lipogenic proteins but elevated lipolytic and fatty acid oxidation proteins. Furthermore, in silico analysis revealed that SPARC directly interacted and regulated VEGF in adipocytes. In conclusion, SPARC acts as a regulatory protein in both white and brown adipocytes by controlling thermogenesis and is thus regarded as a possible therapeutic target for treatment of obesity.

中文翻译：

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分泌的酸性蛋白和富含半胱氨酸（SPARC）调节白色和棕色脂肪细胞的生热作用。

SPARC，又称骨连接素，以其在骨形成和组织重塑以及癌症病理中的生理作用而闻名。然而，缺乏关于其在脂肪细胞中功能的证据。本研究探讨了SPARC在鼠细胞系培养的3T3-L1白色和HIB1B棕色脂肪细胞中的生理作用。重组SPARC的处理上调了白色脂肪细胞和活化的棕色脂肪细胞中的脂肪褐变标记蛋白和基因。相反，敲除Sparc会显着减少两种细胞系中的这些基因和蛋白质。此外，重组SPARC抑制脂肪形成和脂肪形成蛋白的表达，但脂解和脂肪酸氧化蛋白表达升高。此外，计算机分析表明，SPARC与脂肪细胞直接相互作用并调节VEGF。结论，