Tang S, Luo F, Feng Y M, Wei X, Miao H, Lu Y B, Tang Y, Ding D F, Jin J F, Zhu Q
Department of Endocrinology, the Second Affiliated Hospital of Nanjing Medical University, Nanjing, China.
Endocrine and Diabetes Center, Jiangsu Province Hospital on Integration of Chinese and Western Medicine, Nanjing University of Traditional Chinese Medicine, Branch of China Academy of Chinese Medical Science, Nanjing, China.
Exp Clin Endocrinol Diabetes. 2017 Feb;125(2):130-135. doi: 10.1055/s-0042-116314. Epub 2016 Dec 22.
To investigate the effects of neutral ceramidase (NCDase) packaged in exosomes that are secreted from β-cells on free fatty acid (FFA)-induced β-cells apoptosis and its role in regulation of sphingolipid-mediated signaling pathway. HPLC and Western blotting were performed to determine NCDase activity and expression. Annexin V-fluorescein-isothiocyanate/propidium iodide flow cytometry was used to assess apoptosis. Electrospray ionization tandem mass spectrometry was used for ceramide (Cer), sphingosine-1-phosphate (S1P), and sphingosine (SPH) determination. INS-1 cells over-expressed NCDase secreted active NCDase via exosomes. Exosomes isolated from the cultured medium of INS-1 cells that oxpressed NCDase could ameliorate palmitate-induced apoptosis. Furthermore, the results showed that exosome-derived NCDase treatment reduced intracellular Cer/S1P ratio. β-cell secreted active NCDase via exosome, the exosome-packaged-NCDase protected β-cells from FFA-induced apoptosis through regulating sphingolipid metabolites and it might be a potential treatment for β-cell lipotoxicity and type 2 diabetes.
研究β细胞分泌的外泌体中包装的中性神经酰胺酶（NCDase）对游离脂肪酸（FFA）诱导的β细胞凋亡的影响及其在鞘脂介导的信号通路调节中的作用。采用高效液相色谱法（HPLC）和蛋白质免疫印迹法检测NCDase活性和表达。采用膜联蛋白V-异硫氰酸荧光素/碘化丙啶流式细胞术评估细胞凋亡。采用电喷雾电离串联质谱法测定神经酰胺（Cer）、1-磷酸鞘氨醇（S1P）和鞘氨醇（SPH）。过表达NCDase的INS-1细胞通过外泌体分泌活性NCDase。从过表达NCDase的INS-1细胞培养基中分离的外泌体可改善棕榈酸诱导的细胞凋亡。此外，结果表明，外泌体来源的NCDase处理降低了细胞内Cer/S1P比值。β细胞通过外泌体分泌活性NCDase，外泌体包装的NCDase通过调节鞘脂代谢产物保护β细胞免受FFA诱导的凋亡，这可能是治疗β细胞脂毒性和2型糖尿病的潜在方法。
