CNC - Center for Neuroscience and Cell Biology, University of Coimbra, Portugal.
Neuropeptides. 2012 Dec;46(6):359-66. doi: 10.1016/j.npep.2012.08.006. Epub 2012 Sep 13.
The formation of adipose tissue is a process that includes the pre-adipocyte proliferation and differentiation to adipocytes that are cells specialized in lipid accumulation. The adipocyte differentiation is a process driven by the coordinated expression of various transcription factors, such as peroxisome proliferator-activated receptor (PPAR-γ). Neuropeptide Y (NPY) induces adipocyte proliferation and differentiation but the NPY receptors and the intracellular pathways involved in these processes are still not clear. In the present work we studied the role of NPY receptors and the intracellular pathways involved in the stimulatory effect of NPY on lipid accumulation. The murine pre-adipocyte cell line, 3T3-L1, was used as a cell model. Adipogenesis was evaluated by quantifying lipid accumulation by Oil red-O assay and by analyzing PPAR-γ expression using the Western blotting assay. Adipocytes were incubated with NPY (100nM) and a decrease on lipid accumulation and PPAR-γ expression was observed in the presence of NPY Y(2) receptor antagonist (BIIE0246, 1μM) or NPY Y(5) antagonist. Furthermore, NPY Y(2) (NPY(3-36), 100nM) or NPY Y(5) (NPY(19-23)(GLY(1), Ser(3), Gln(4), Thr(6), Ala(31), Aib(32), Gln(34)) PP, 100nM) receptor agonists increased lipid accumulation and PPAR-γ expression. We further investigate the intracellular pathways associated with NPY Y(2) and NPY Y(5) receptor activation. Our results show NPY induces PPAR-γ expression and lipid accumulation through NPY Y(2) and NPY Y(5) receptors activation. PKC and PLC inhibitors inhibit lipid accumulation induced by NPY Y(5) receptor agonist. Moreover, our results suggest that lipid accumulation induced by NPY Y(2) receptor activation occurs through PKA, MAPK and PI3K pathways. In conclusion, this study contributes to a step forward on the knowledge of intracellular mechanisms associated with NPY receptors activation on adipocytes and contributes to a better understanding and the development of new therapeutic targets for obesity treatment.
脂肪组织的形成是一个包括前脂肪细胞增殖和分化为专门积累脂质的脂肪细胞的过程。脂肪细胞分化是一个由各种转录因子协调表达驱动的过程，如过氧化物酶体增殖物激活受体 (PPAR-γ)。神经肽 Y (NPY) 诱导脂肪细胞增殖和分化，但 NPY 受体和参与这些过程的细胞内途径仍不清楚。在本工作中，我们研究了 NPY 受体和参与 NPY 对脂质积累的刺激作用的细胞内途径的作用。使用小鼠前脂肪细胞系 3T3-L1 作为细胞模型。通过油红-O 测定法定量脂质积累来评估脂肪生成，并通过 Western 印迹分析测定 PPAR-γ 表达。用 NPY (100nM) 孵育脂肪细胞，并在存在 NPY Y(2) 受体拮抗剂 (BIIE0246，1μM) 或 NPY Y(5) 拮抗剂的情况下观察到脂质积累和 PPAR-γ 表达减少。此外，NPY Y(2) (NPY(3-36)，100nM) 或 NPY Y(5) (NPY(19-23)(GLY(1)，Ser(3)，Gln(4)，Thr(6)，Ala(31)，Aib(32)，Gln(34)) PP，100nM) 受体激动剂增加了脂质积累和 PPAR-γ 表达。我们进一步研究了与 NPY Y(2) 和 NPY Y(5) 受体激活相关的细胞内途径。我们的结果表明，NPY 通过 NPY Y(2) 和 NPY Y(5) 受体激活诱导 PPAR-γ 表达和脂质积累。PKC 和 PLC 抑制剂抑制 NPY Y(5) 受体激动剂诱导的脂质积累。此外，我们的结果表明，NPY Y(2) 受体激活诱导的脂质积累是通过 PKA、MAPK 和 PI3K 途径发生的。总之，这项研究有助于深入了解与脂肪细胞中 NPY 受体激活相关的细胞内机制，并有助于更好地理解和开发肥胖治疗的新治疗靶点。
