Laboratory of Neurovascular Inflammation and Neurodegeneration, Department of Biomedical Engineering, Center for Injury Bio Mechanics, Materials and Medicine, New Jersey Institute of Technology, 111 Lock Street, Newark, NJ, 07102, USA.
Department of Pharmacology and Experimental Neuroscience, University of Nebraska Medical Center, Omaha, NE, 68198, USA.
Mol Neurobiol. 2018 Jul;55(7):5937-5950. doi: 10.1007/s12035-017-0811-0. Epub 2017 Nov 11.
Wernicke's encephalopathy, a common neurological disease, is caused by thiamine (vitamin B1) deficiency. Neuropathy resulting from thiamine deficiency is a hallmark of Wernicke-Korsakoff syndrome in chronic alcohol users. The underlying mechanisms of this deficiency and progression of neuropathy remain to be understood. To uncover the unknown mechanisms of thiamine deficiency in alcohol abuse, we used chronic alcohol consumption or thiamine deficiency diet ingestion in animal models. Observations from animal models were validated in primary human neuronal culture for neurodegenerative process. We employed radio-labeled bio-distribution of thiamine, qualitative and quantitative analyses of the various biomarkers and neurodegenerative process. In the present studies, we established that disruption of thiamine transport across the intestinal gut blood-brain barrier axis as the cause of thiamine deficiency in the brain for neurodegeneration. We found that reduction in thiamine transport across these interfaces was the cause of reduction in the synthesis of thiamine pyrophosphate (TPP), an active cofactor for pyruvate dehydrogenase E1α (PDHE1α). Our findings revealed that decrease in the levels of PDHE1α cofactors switched on the activation of PD kinase (PDK) in the brain, thereby triggering the neuronal phosphorylation of PDHE1α (p-PDHE1α). Dysfunctional phosphorylated PDHE1α causes the reduction of mitochondrial aerobic respiration that led to neurodegeneration. We concluded that impairment of thiamine transport across the gut-BBB-axis that led to insufficient TPP synthesis was critical to Wernicke-neuropathy, which could be effectively prevented by stabilizing the thiamine transporters.
威尼克脑病，一种常见的神经疾病，是由硫胺素（维生素 B1）缺乏引起的。由于硫胺素缺乏引起的神经病变是慢性酒精使用者威尼克-科尔萨科夫综合征的标志。这种缺乏和神经病变进展的潜在机制仍有待了解。为了揭示酒精滥用中硫胺素缺乏的未知机制，我们在动物模型中使用慢性酒精消耗或硫胺素缺乏饮食摄入。动物模型的观察结果在原代人神经元培养物中得到了神经退行性过程的验证。我们采用放射性标记的硫胺素生物分布、各种生物标志物的定性和定量分析以及神经退行性过程。在本研究中，我们确定了跨肠道血脑屏障轴的硫胺素转运中断是导致大脑中硫胺素缺乏和神经退行性变的原因。我们发现，这些界面上的硫胺素转运减少是导致硫胺素焦磷酸（TPP）合成减少的原因，TPP 是丙酮酸脱氢酶 E1α（PDHE1α）的活性辅因子。我们的研究结果表明，PDHE1α 辅因子水平的降低会激活大脑中的 PD 激酶（PDK），从而触发 PDHE1α 的神经元磷酸化（p-PDHE1α）。功能失调的磷酸化 PDHE1α 导致线粒体需氧呼吸减少，从而导致神经退行性变。我们得出结论，跨肠-脑血屏障轴的硫胺素转运受损导致 TPP 合成不足是威尼克神经病的关键，通过稳定硫胺素转运体可以有效地预防。
