Vitamin B1 (thiamin) transport in Alzheimer’s Disease: Role of microRNAs in regulating level of expression of its transporters (SLC19A2 & SLC19A3) in human brain cells and effect of hypoxia

项目摘要/摘要 阿尔茨海默病(AD)是一种以淀粉样蛋白β为特征的进行性神经退行性疾病 含有多肽的斑块、神经原纤维缠结、脑内神经元丢失和认知缺陷。常量 该病的特征包括糖/能量代谢受损、氧化应激和线粒体。 脑细胞功能障碍。 维生素B1(硫胺素，也被称为“能量维生素”)对于正常的细胞功能是不可或缺的。 和新陈代谢。硫胺素是参与关键代谢反应的多种酶的辅因子。 包括氧化能量代谢，三磷酸腺苷的产生，减少细胞的氧化应激；它还 具有抗炎作用。因此，细胞中硫胺素的缺乏导致 能量代谢受损，细胞ATP水平降低，以及氧化应激倾向；它还 导致线粒体功能/结构受损。 大量证据表明，维生素B1缺乏会加重AD的病理，而且 在这种神经退行性疾病中，硫胺素稳态/生理学发生改变。后者包括 我们实验室最近发表的研究结果表明，细胞膜硫胺素的表达水平 转运蛋白-1和-2(THTR-1和-2；SLC19A2和SLC19A3基因产物)在 阿尔茨海默病患者脑组织与对照组的比较。 MicroRNAs(MiRNAs)是一组发挥基因沉默作用的非编码单链小RNA 效果。它们调节多种细胞功能，包括跨细胞膜的运输。的表达 MiRNAs是组织特异性的；同样，miRNA对目标蛋白的影响可能是细胞特异性的。在新的 初步研究，我们获得的证据表明，THTR-1在人类 分化神经母细胞瘤SH-SY5Y细胞受miRNAs调控(其中几个已被证明是 在AD中诱导)。在另一项初步研究中，我们发现缺氧(一种导致不同 AD的病理方面)导致硫胺素摄取和THTR-1表达水平显著抑制 &2在人神经母细胞瘤SH-SY5Y细胞中的表达。基于这些初步发现，我们假设 在本补充应用中，THTR-1和-2在脑细胞中的表达水平由miRNAs调节， 低氧对这些细胞的硫胺素摄取生理/分子生物学产生有害影响。我们会 通过实现两个特定目标来检验这些假设：1)检查miRNAs在调节水平中的作用 2)检测低氧对硫胺素摄取的影响。 并描述了相关的细胞/分子机制(S)。我们将使用互补性 人分化SH-SY5Y细胞、原代神经元和人脑有机体模型的建立 调查。

PROJECT SUMMARY/ABSTRACT Alzheimer’s disease (AD) is a progressive neurodegenerative disease characterized by Amyloid-β peptide-containing plaques, neurofibrillary tangles, neuronal loss in the brain, and cognitive deficits. Constant features of the disease include impaired glucose/energy metabolism, oxidative stress, and mitochondrial dysfunction in brain cells. Vitamin B1 (thiamin; also referred to as the “energy vitamin”) is indispensable for normal cellular function and metabolism. Thiamin serves as cofactor for multiple enzymes that are involved in critical metabolic reactions including oxidative energy metabolism, ATP production, and reduction of cellular oxidative stress; it also possesses anti-inflammatory properties. Thus, it is not surprising that cellular deficiency of thiamin leads to impairment in energy metabolism, reduction in cellular ATP level, and to a propensity for oxidative stress; it also leads to impairment in the function/structure of mitochondria. A wealth of evidence exist showing that vitamin B1 deficiency aggravates the pathology of AD, and that alterations in thiamine homeostasis/physiology occur in this neurodegenerative disease. The latter includes recently published findings from our laboratory showing that the level of expression of the cell membrane thiamin transporters-1 & -2 (THTR-1 & -2; products of the SLC19A2 and SLC19A3 genes) are significantly reduced in brain tissues of AD patients compared to control subjects. MicroRNAs (miRNAs) are a group of small noncoding single-stranded RNAs that exert gene-silencing effects. They regulate a variety of cellular functions including transport across cell membrane. Expression of miRNAs is tissue-specific; also effect of a miRNA on a target protein could be cell-specific in nature. In new preliminary studies, we obtained evidence suggesting that the level of expression of THTR-1 in human differentiated neuroblastoma SH-SY5Y cells is regulated by miRNAs (several of which have been shown to be induced in AD). In another preliminary study, we found that hypoxia (a condition that contributes to different pathological aspects of AD) causes significant inhibition in thiamin uptake and in level of expression of THTR-1 & -2 in human differentiated neuroblastoma SH-SY5Y cells. Based on these preliminary findings, we hypothesize in this supplement application that the level of expression of THTR-1 & -2 in brain cells is regulated by miRNAs, and that hypoxia exert deleterious effects on thiamin uptake physiology/molecular biology in these cells. We will test these hypotheses by accomplishing two specific aims: 1) Examine the role of miRNAs in regulating the level of expression of THTR-1 & -2 in human brain cells; and 2) Examine the effect of hypoxia on thiamin uptake by human brain cells and delineate the cellular/molecular mechanism(s) involved. We will use complementary models of human differentiated SH-SY5Ycells, human primary neurons, and human brain organoids in our investigations.