Institutes of Brain Science & Collaborative Innovation Center for Brain Science; Department of Neurology, Zhongshan Hospital; State Key Laboratory of Medical Neurobiology, Fudan University, Shanghai, 200032, China.
School of Life Sciences, Fudan University, Shanghai, 200438, China.
Sci Rep. 2017 Jul 13;7(1):5342. doi: 10.1038/s41598-017-05476-w.
Thiamine is critical for cellular function, as its phosphorylated and active form, thiamine diphosphate (TDP), acts as coenzyme for three key enzymes in glucose metabolism. Mutations in thiamine transporter, TDP synthesizing enzyme or carrier, including solute carrier family 19 member 3 (SLC19A3), thiamine pyrophosphokinase (TPK1) and solute carrier family 25 member 19 (SLC25A19), have been associated with developmental neurological disorders, including microcephaly and Leigh syndrome. However, little is known about how thiamine metabolism regulates neuronal morphology at the cellular level. Here, using primary rat hippocampal neuronal cultures, we showed that reducing the expression of Tpk1, Slc25a19 or Slc19a3 in individual neurons significantly reduced dendrite complexity, as measured by total dendritic branch tip number (TDBTN) and total dendritic branch length (TDBL). The specificity of the RNAi effects were verified by overexpression of RNAi resistant human constructs. Importantly, changes in both TDBTN and TDBL tightly correlated with reduction in soma size, demonstrating coordinated regulation of soma and dendrite growth by thiamine. The requirement of thiamine metabolism for coordinated somata and dendrite growth is highly consistent with the microcephaly and neurodegenerative phenotypes observed in thiamine loss-of-function diseases.
硫胺素对于细胞功能至关重要，因为其磷酸化和活性形式，硫胺素二磷酸（TDP），作为葡萄糖代谢中三种关键酶的辅酶。硫胺素转运蛋白、TDP 合成酶或载体（包括溶质载体家族 19 成员 3（SLC19A3）、硫胺素焦磷酸激酶（TPK1）和溶质载体家族 25 成员 19（SLC25A19））的突变与发育性神经紊乱有关，包括小头症和 Leigh 综合征。然而，对于硫胺素代谢如何在细胞水平上调节神经元形态知之甚少。在这里，我们使用原代大鼠海马神经元培养物表明，在单个神经元中降低 Tpk1、Slc25a19 或 Slc19a3 的表达显著降低了树突复杂性，如总树突分支末端数（TDBTN）和总树突分支长度（TDBL）所示。RNAi 效应的特异性通过过表达 RNAi 抗性人构建体得到验证。重要的是，TDBTN 和 TDBL 的变化与体细胞大小的减少密切相关，表明硫胺素对体细胞和树突生长的协调调节。硫胺素代谢对于协调的体细胞和树突生长的需求与硫胺素功能丧失疾病中观察到的小头症和神经退行性表型高度一致。
