Department of Endocrinology, Drum Tower Clinical College of Nanjing Medical University, Nanjing, Jiangsu, China.
Department of Neurochemistry, Inge Grundke-Iqbal Research Floor, New York State Institute for Basic Research in Developmental Disabilities, Staten Island, NY, USA.
J Alzheimers Dis. 2020;75(4):1339-1349. doi: 10.3233/JAD-200101.
Evidence from clinical studies and basic research has shown a strong correlation between Alzheimer's disease (AD) and type 2 diabetes. Tau, a neuronal microtubule-associated protein, is hyperphosphorylated and aggregated into neurofibrillary tangles in the AD brain. However, the expression of tau in pancreas is under debate.
We determined the expression of tau in mouse pancreas.
We used western blots, immunoprecipitation, and immunohistochemical staining to analyze pancreatic expression of tau in mice.
We found that neither total tau nor phosphorylated tau was detectable in the mouse pancreas by western blots. Immunostaining with pan tau antibodies R134d and Tau-5 revealed bright and dense varicosities in the pancreatic islets and the exocrine pancreas. These varicosities were immunoreactive to synapsin 1, a presynaptic marker which can outline autonomic nerve profiles in pancreas, exhibiting complete colocalization with tau. Importantly, endocrine cells in islets did not exhibit specific immunoreactivity to any of pan tau antibodies tested, nor did the exocrine cells.
In the mouse pancreas, we found that tau is exclusively expressed in autonomic nerve fibers, but there is no detectable expression in endocrine cells in the islet.
临床研究和基础研究的证据表明阿尔茨海默病（AD）与 2 型糖尿病之间存在很强的相关性。Tau 是一种神经元微管相关蛋白，在 AD 大脑中会过度磷酸化并聚集成神经纤维缠结。然而，Tau 在胰腺中的表达仍存在争议。
我们确定了 Tau 在小鼠胰腺中的表达。
我们使用 Western blot、免疫沉淀和免疫组织化学染色来分析小鼠胰腺中 Tau 的表达。
我们发现 Western blot 无法检测到小鼠胰腺中的总 Tau 或磷酸化 Tau。用泛 Tau 抗体 R134d 和 Tau-5 进行免疫染色，在胰岛和外分泌腺中显示出明亮而密集的空泡。这些空泡与突触素 1 免疫反应性强，突触素 1 是一种突触前标志物，可以勾勒出胰腺中的自主神经轮廓，与 Tau 完全共定位。重要的是，胰岛中的内分泌细胞对任何测试的泛 Tau 抗体均无特异性免疫反应，外分泌细胞也没有。
在小鼠胰腺中，我们发现 Tau 仅在自主神经纤维中表达，而在胰岛的内分泌细胞中无法检测到。
