Department of Food Science , University of Guelph , Guelph , Ontario N1G 2W1 , Canada.
Key Laboratory of Meat Processing and Quality Control , Nanjing Agricultural University , Nanjing 210000 , China.
J Agric Food Chem. 2019 Jul 31;67(30):8361-8369. doi: 10.1021/acs.jafc.9b02334. Epub 2019 Jul 24.
The calcium-sensing receptor (CaSR), a G-protein receptor, is well recognized for its role in the regulation of adipocyte proliferation, in modulating adipose tissue dysfunction, and as a potential target for therapeutic intervention. In the present study, we investigate the anti-inflammatory effect of γ-glutamylvaline (γ-EV) on mouse adipocytes and explore the role of γ-EV-activated CaSR in the regulation of cellular homeostasis using the mouse 3T3-L1 cell line in vitro model. Our results indicate that the 3T3-L1 adipocyte-like cells accumulated lipids and expressed CaSR after 2 days of differentiation and 7 days of maturation period. The pretreatment with γ-EV (10 μM) suppressed the production of TNF-α-induced pro-inflammatory cytokines, i.e., IL-6 (23.92 ± 5.45 ng/mL, < 0.05)) and MCP-1 (101.17 ± 39.93 ng/mL, < 0.05), while enhancing the expression of PPARγ (1.249 ± 0.109, < 0.001) and adiponectin (7.37 ± 0.59 ng/mL, < 0.05). Elevated expression of Wnt5a was detected in γ-EV-treated cells (115.90 ± 45.50, < 0.001), suggesting the involvement of the Wnt/β-catenin pathway. Also, phosphorylation of β-catenin was shown to be significantly inhibited (0.442 ± 0.034) by TNF-α but restored when cells were pretreated with γ-EV (0.765 ± 0.048, < 0.05). These findings suggest that γ-EV-induced CaSR activation not only prevents TNF-α-induced inflammation in adipocytes but also modulates the cross-talk between Wnt and PPARγ pathways. Concentrations of serine phosphorylated IRS-1 were shown to be lower in γ-EV-treated cells, indicating γ-EV may also prevent inflammation in the context of insulin resistance. Thus, γ-EV-activated CaSR plays a significant role in the cross-talk between adipocyte inflammatory and metabolic pathways through the regulation of extracellular sensing.
钙敏感受体（CaSR）是一种 G 蛋白受体，其在调节脂肪细胞增殖、调节脂肪组织功能障碍以及作为治疗干预的潜在靶点方面的作用已得到广泛认可。在本研究中，我们研究了 γ-谷氨酰缬氨酸（γ-EV）对小鼠脂肪细胞的抗炎作用，并使用体外 3T3-L1 细胞系模型探索了 γ-EV 激活的 CaSR 在调节细胞内稳态中的作用。我们的结果表明，在分化 2 天和成熟 7 天后，3T3-L1 脂肪细胞样细胞积累了脂肪并表达了 CaSR。用 γ-EV（10 μM）预处理可抑制 TNF-α诱导的促炎细胞因子（即 IL-6（23.92 ± 5.45ng/mL， < 0.05）和 MCP-1（101.17 ± 39.93ng/mL， < 0.05）的产生，同时增强 PPARγ（1.249 ± 0.109， < 0.001）和脂联素（7.37 ± 0.59ng/mL， < 0.05）的表达。在 γ-EV 处理的细胞中检测到 Wnt5a 的表达升高（115.90 ± 45.50， < 0.001），表明 Wnt/β-catenin 途径的参与。此外，TNF-α显著抑制了 β-catenin 的磷酸化（0.442 ± 0.034），而当细胞用 γ-EV 预处理时，β-catenin 的磷酸化得到恢复（0.765 ± 0.048， < 0.05）。这些发现表明，γ-EV 诱导的 CaSR 激活不仅可以防止 TNF-α诱导的脂肪细胞炎症，还可以调节 Wnt 和 PPARγ 途径之间的串扰。在 γ-EV 处理的细胞中，丝氨酸磷酸化的 IRS-1 浓度较低，表明 γ-EV 还可以在胰岛素抵抗的情况下预防炎症。因此，γ-EV 激活的 CaSR 通过调节细胞外感应，在脂肪细胞炎症和代谢途径的串扰中发挥重要作用。
