Functional Genomics Laboratory, CREMI, Québec Genome Center, CHUL-CHU de Québec Research Center, Québec, Québec G1V 4G2, Canada; Department of Molecular Medicine, Faculty of Medicine, Laval University, Québec, Québec G1V 0A6, Canada.
Functional Genomics Laboratory, CREMI, Québec Genome Center, CHUL-CHU de Québec Research Center, Québec, Québec G1V 4G2, Canada.
Int J Biochem Cell Biol. 2019 Dec;117:105627. doi: 10.1016/j.biocel.2019.105627. Epub 2019 Oct 4.
The extracellular matrix (ECM) remodeling plays important roles in both adipocytes shape/expansion remodeling and the skeletal muscle (SM) metabolism. Secreted protein acidic and rich in cysteine (SPARC) is expressed in divers tissues including adipose tissue (AT) and SM where it impacts a variety of remodeling as well as metabolic functions. SPARC, also known as osteonectin or BM-40, is a glycoprotein associated with the ECM. Numerous researches attempted to elucidate the implications of SPARC in these two key metabolic tissues under different conditions. Whereas SPARC deficiency tends to shape the remodeling of the adipocytes and the fat distribution, this deficiency decreases SM metabolic properties. On the other hand, SPARC seems to be an enhancer of the metabolism and a mediator of the exercise-induced adaptation in the SM and as well as an adipogenesis inhibitor. Some findings about the SPARC effects on AT and SM seem "contradictory" in terms of tissue development and energy profile therefore highlighting the mechanistic role of SPARC in both is a priority. Yet, within this review, we expose selected researches and compare the results. We conclude with explanations to "reconcile" the different observations, hypothesize the feedback and regulatory character of SPARC and put its roles within the energetic and structural maps of both adipocytes and myocytes in homeostasis and in situations such as obesity or exercise. These properties explain the modifications and the remodeling seen in AT and SM undergoing adaptive changes (obesity, exercise, etc.) and represent a starting point for precise therapeutic targeting of SPARC-related pathways is conditions such as obesity, sarcopenia and diabetes.
细胞外基质（ECM）重塑在脂肪细胞形态/扩张重塑和骨骼肌（SM）代谢中都起着重要作用。富含半胱氨酸的酸性分泌蛋白（SPARC）在包括脂肪组织（AT）和 SM 在内的多种组织中表达，它影响多种重塑和代谢功能。SPARC，也称为骨粘连蛋白或 BM-40，是一种与 ECM 相关的糖蛋白。许多研究试图阐明 SPARC 在这两种关键代谢组织中的不同条件下的意义。虽然 SPARC 缺乏倾向于塑造脂肪细胞的重塑和脂肪分布，但这种缺乏会降低 SM 的代谢特性。另一方面，SPARC 似乎是 SM 代谢和运动诱导适应的增强剂，也是脂肪生成的抑制剂。关于 SPARC 对 AT 和 SM 的影响的一些发现，就组织发育和能量谱而言，似乎“相互矛盾”，因此突出了 SPARC 在这两种组织中的机制作用是当务之急。然而，在这篇综述中，我们展示了一些选定的研究并比较了结果。我们以解释来“调和”不同的观察结果，假设 SPARC 的反馈和调节特征，并将其作用置于脂肪细胞和肌细胞的能量和结构图谱中，以维持体内平衡和肥胖或运动等情况。这些特性解释了在适应变化（肥胖、运动等）过程中 AT 和 SM 中看到的改变和重塑，代表了针对肥胖症、肌少症和糖尿病等情况下与 SPARC 相关途径进行精确治疗靶向的起点。
