Pennington Biomedical Research Center, Baton Rouge, LA 70808, USA.
Peptides. 2009 Dec;30(12):2275-80. doi: 10.1016/j.peptides.2009.08.023. Epub 2009 Sep 9.
We recently reported that mouse astrocytes express leptin receptors (ObR), and that obesity induces upregulation of astrocytic ObR. To provide further evidence of the importance of astrocytic ObR expression, we performed double-labeling fluorescent in situ hybridization (FISH) and immunohistochemistry in the rat hypothalamus. Laser confocal microscopic image analysis showed that ObR mRNA was present in glial fibrillary acidic protein (+) cells that show distinctive astrocytic morphology as well as in neurons. In addition to the presence of ObR mRNA, ObR protein was shown in both astrocytes and neurons in the rat hypothalamus by double-labeling immunohistochemistry. In cultured rat C6 astrocytoma cells treated with different doses of lipopolysaccharide for 6h, the mRNA for ObRa or ObRb did not show significant changes, as measured by quantitative RT-PCR. However, the protein expression of both ObRa and ObRb, determined by Western blotting, was increased after the C6 cells were treated with either lipopolysaccharide or tumor necrosis factor-alpha. The results indicate that astrocytic ObR expression is present in rats as well as mice, and that it probably plays a role in the neuroinflammatory response.
我们最近报道了小鼠星形胶质细胞表达瘦素受体(ObR),肥胖诱导星形胶质细胞 ObR 的上调。为了提供星形胶质细胞 ObR 表达重要性的进一步证据,我们在大鼠下丘脑进行了双标荧光原位杂交(FISH)和免疫组织化学研究。激光共聚焦显微镜图像分析显示,ObR mRNA 存在于胶质纤维酸性蛋白(+)细胞中,这些细胞具有独特的星形胶质细胞形态,也存在于神经元中。通过双标免疫组织化学,除了存在 ObR mRNA 外,还在大鼠下丘脑的星形胶质细胞和神经元中显示出 ObR 蛋白。在培养的大鼠 C6 星形细胞瘤细胞中,用不同剂量的脂多糖处理 6 小时后,通过定量 RT-PCR 测量,ObRa 或 ObRb 的 mRNA 没有显示出明显变化。然而,用脂多糖或肿瘤坏死因子-α处理 C6 细胞后,通过 Western blot 测定,ObRa 和 ObRb 的蛋白表达均增加。结果表明,星形胶质细胞 ObR 表达不仅存在于小鼠中,也存在于大鼠中,并且可能在神经炎症反应中发挥作用。