Characterization of TMEM251 that causes a new type of severe lysosome storage disease

引起新型严重溶酶体贮积病的 TMEM251 的表征

基本信息

批准号：
10502880
负责人：
Ming Li
金额：
$ 43.24万
依托单位：
UNIVERSITY OF MICHIGAN AT ANN ARBOR
依托单位国家：
美国
项目类别：
财政年份：
2022
资助国家：
美国
起止时间：
2022-09-15 至 2027-08-31
项目状态：
未结题

来源：
https://reporter.nih.gov/project-details/10502880
关键词：
Address Affect Autophagocytosis Binding Biogenesis Bone Development Cardiac Edema Cardiomegaly Cell physiology Cessation of life Child Development Child Health Clustered Regularly Interspaced Short Palindromic Repeats Comparative Study Complex Data Defect Development Disease Down-Regulation Endocytic Vesicle Endocytosis Enzymes Functional disorder Genes Golgi Apparatus Heart Abnormalities Human Human Pathology I-Cell Disease Impairment Integral Membrane Protein Journals Knock-out Label Light Lysosomal Storage Diseases Lysosomes Maps Mass Spectrum Analysis Membrane Membrane Proteins Metabolism Modification Molecular Mutation N-acetylglucopyranosylamine Nutrient Organelles Paper Pathway interactions Patients Phosphotransferases Plasma Reporting Research Role Signal Transduction Sorting - Cell Movement TFE3 gene Tail Testing Text Up-Regulation Vertebrates Zebrafish cardiogenesis early childhood genome-wide in vivo lysosome membrane mannose 6 phosphate mutant skeletal dysplasia trafficking transcriptome sequencing treatment strategy

项目摘要

The lysosome is an essential organelle to recycle materials delivered by endocytosis and autophagy. Inborn genetic defects affecting the lysosome cause debilitating and fatal lysosomal storage diseases (LSDs, ~70 in humans). One severe form of LSD, the I-cell disease, leads to skeletal dysplasia, short stature, cardiomegaly, and death in the first decade. It is caused by mutations in the GlcNAc-1-phosphotransferase enzyme (GNPT), which functions at the cis- Golgi to label lysosome enzymes with sorting signal mannose-6-phosphate (M6P). Missing M6P leads to the secretion of most lysosomal enzymes and defective lysosomes. In early 2021, a new type of severe LSD similar to the I-cell disease was reported. Patients will develop skeletal dysplasia, short stature, cardiac defects, and some die in early childhood. Their lysosomal enzymes are also secreted into the plasma. It is caused by mutations in TMEM251, but the cellular function of TMEM251 and the molecular mechanism for the disease remain to be addressed. In a genome-wide CRISPR knockout screen to identify genes critical for the degradation of human lysosome membrane proteins, we independently discovered TMEM251 to be essential for lysosome function. Knocking out TM251 leads to lysosomal dysfunction due to the secretion of unprocessed lysosomal enzymes. Consequently, lysosomes accumulate numerous undigested materials such as autophagic bodies and endocytic vesicles. Consistent with human pathology, knocking out TM251 in Zebrafish leads to cardiac defects and skeletal dysplasia. We hypothesize that TM251 functions in the M6P biogenesis pathway of lysosomal enzymes. We will pursue three specific aims to characterize the role of TM251 in lysosome biogenesis. In aim 1, we will characterize membrane topology, localization, and oligomerization of TM251. In aim 2, we will dissect the relationship between TM251 and the GNPT complex at both cellular and organismal levels. In aim 3, we will study the signaling cascade that leads to lysosome upregulation after knocking out TM251. Our findings will uncover the role of TM251 in the M6P biogenesis and provide a molecular mechanism for a new lysosome storage disease that severely affects child health.

溶酶体是回收通过内吞作用传递的物质的重要细胞器，自噬。影响溶酶体的先天遗传缺陷会导致溶酶体衰弱和致命贮藏病（LSD，人类约 70 种）。 LSD 的一种严重形式，即 I 细胞疾病，会导致骨骼发育不良、身材矮小、心脏肥大，并在最初十年内死亡。这是由 GlcNAc-1-磷酸转移酶 (GNPT) 的突变，该酶在顺式- 高尔基体用分选信号 6-磷酸甘露糖 (M6P) 标记溶酶体酶。失踪的M6P 导致大多数溶酶体酶和有缺陷的溶酶体的分泌。 2021 年初，据报道，有一种类似于 I 细胞疾病的新型严重 LSD。患者的骨骼会发育发育不良、身材矮小、心脏缺陷，有的在幼儿期死亡。他们的溶酶体酶也分泌到血浆中。它是由 TMEM251 突变引起的，但 TMEM251的细胞功能和该疾病的分子机制仍有待进一步研究已解决。在全基因组 CRISPR 敲除筛选中，识别对降解至关重要的基因人类溶酶体膜蛋白，我们独立发现TMEM251是必不可少的用于溶酶体功能。敲除TM251会因分泌而导致溶酶体功能障碍未经加工的溶酶体酶。因此，溶酶体积累了大量的未消化的物质，例如自噬体和内吞囊泡。与人类一致从病理学角度来看，敲除斑马鱼中的 TM251 会导致心脏缺陷和骨骼发育不良。我们假设 TM251 在溶酶体酶的 M6P 生物合成途径中发挥作用。我们将追求三个具体目标来表征 TM251 在溶酶体生物发生中的作用。在目标 1，我们将表征 TM251 的膜拓扑、定位和寡聚化。在目标2，我们将在细胞和细胞层面剖析TM251和GNPT复合物之间的关系和有机体水平。在目标 3 中，我们将研究导致溶酶体的信号级联敲除 TM251 后上调。我们的研究结果将揭示 TM251 在 M6P 中的作用生物发生并为新的溶酶体贮积病提供分子机制严重影响儿童健康。