Role of ACTG2 Mutations in Visceral Myopathy

ACTG2 突变在内脏肌病中的作用

基本信息

批准号：
9904604
负责人：
Sohaib Khalid Hashmi
金额：
$ 3.26万
依托单位：
UNIVERSITY OF PENNSYLVANIA
依托单位国家：
美国
项目类别：
财政年份：
2018
资助国家：
美国
起止时间：
2018-06-01 至 2021-05-31
项目状态：
已结题

来源：
https://reporter.nih.gov/project-details/9904604
关键词：
Abdomen Abdominal Pain Actins Acute Address Affect Alleles Arginine Binding Proteins Biochemical Biochemistry Biological Models Bladder CRISPR/Cas technology Catheterization Cell Differentiation process Cells Chimeric Proteins Chronic Colon Constipation Contracts Cysteine Cytoskeletal Proteins Cytoskeleton Defect Deterioration Disease Dominant-Negative Mutation Electron Microscopy Failure Family Fibroblasts Fibrosis Fluorescence Recovery After Photobleaching Fluorescent Probes Food Functional disorder Generations Genes Genetic Transcription Goals Growth Heterozygote Hospitals Human Impairment In Vitro Individual Infant Intestinal Pseudo-Obstruction Intestines Intravenous Lead Life Measures Medical Messenger RNA Methods Microfilaments Missense Mutation Molecular Morbidity - disease rate Movement Muscle Weakness Muscle function Mutation Myosin ATPase Nonsense Mutation Operative Surgical Procedures Pathogenicity Pharmaceutical Preparations Point Mutation Process Protein Isoforms Proteins Repeat Surgery Role Severities Severity of illness Small Intestines Smooth Muscle Smooth Muscle Actin Staining Method Smooth Muscle Myocytes Structure Symptoms Syndrome System Testing Time Traction Force Microscopy Transplantation Uterus Visceral Visceral Myopathies Vomiting Work base fluorescence imaging high-throughput drug screening human disease human pluripotent stem cell live cell imaging motility disorder mutant myocardin novel nutrition prevent response to injury transcription factor treatment strategy

项目摘要

Project Summary: Myopathic chronic intestinal pseudo-obstruction (CIPO) and Megacystis Microcolon Intestinal Hypoperistalsis Syndrome (MMIHS) are life-threatening bowel motility disorders characterized by visceral (bowel, bladder, and uterine) smooth muscle weakness. Symptoms include bowel and bladder distension, abdominal pain, vomiting, constipation, and growth failure. Many people with CIPO and MMIHS need intravenous nutrition at least intermittently and affected individuals often have repeated surgery and spend months in the hospital. Current therapy is largely ineffective so some people with CIPO or MMIHS undergo small bowel transplantation. None of the medical therapies address underlying disease mechanisms and no current therapy makes bowel smooth muscle stronger. Furthermore, molecular mechanisms causing visceral muscle weakness are barely investigated. Within the past few years, it was discovered that heterozygous point mutations in gamma smooth muscle actin (actin, gamma 2; ACTG2), the predominant actin isoform in visceral smooth muscle, occur in almost half of people with CIPO and MMIHS. This work is focused on the most commonly identified ACTG2 mutation (arginine 257 to cysteine, R257C). The goal is to determine how this mutation affects actin cytoskeletal structure, actin dynamics, and force generation by smooth muscle cells. Studies will also test the hypothesis that ACTG2 R257C alters smooth muscle differentiation. The model system employs human intestinal smooth muscle cells and a novel paradigm for converting human pluripotent stem cells to visceral smooth muscle-like cells. Diverse experimental approaches will be employed including live cell imaging using actin filament binding proteins, live cell imaging of fluorescently tagged actin, actin cytoskeleton analysis in fixed cells, electron microscopy of the actin cytoskeleton, traction force microscopy to measure contractile strength of smooth muscle cells, and several molecular methods to assess relevant mRNA and protein levels in cultured visceral smooth muscle. These studies should define how ACTG2 R257C causes devastating smooth muscle weakness and may lead to novel mechanism-based treatment strategies. In particular, in vitro defects that define the underlying pathophysiology of ACTG2 mutations, will provide a platform for high-throughput drug screening to discover new treatments for CIPO/MMIHS.

项目摘要：肌病性慢性假性肠梗阻 (CIPO) 和巨囊微结肠肠道蠕动功能减退综合征 (MMIHS) 是一种危及生命的肠道动力障碍，其特征为内脏（肠、膀胱和子宫）平滑肌无力。症状包括肠道和膀胱腹胀、腹痛、呕吐、便秘和生长障碍。许多拥有 CIPO 和 MMIHS 的人需要静脉营养至少是间歇性的，受影响的个体经常需要重复手术并花费在医院住了几个月。目前的治疗基本上无效，因此一些 CIPO 或 MMIHS 患者会接受小规模治疗肠移植。没有任何药物疗法能解决潜在的疾病机制，目前也没有治疗使肠平滑肌变得更强。此外，引起内脏肌的分子机制弱点几乎没有被调查。在过去的几年里，人们发现杂合点突变 γ 平滑肌肌动蛋白（肌动蛋白，γ 2；ACTG2）是内脏平滑肌中的主要肌动蛋白亚型几乎一半的 CIPO 和 MMIHS 患者都会出现这种情况。这项工作主要关注最常见的鉴定出 ACTG2 突变（精氨酸 257 变为半胱氨酸，R257C）。目标是确定这种突变如何影响肌动蛋白细胞骨架结构、肌动蛋白动力学和平滑肌细胞产生的力。研究还将测试 ACTG2 R257C 改变平滑肌分化的假设。该模型系统采用人类肠道平滑肌细胞和将人类多能干细胞转化为内脏干细胞的新范例平滑肌样细胞。将采用多种实验方法，包括使用活细胞成像肌动蛋白丝结合蛋白、荧光标记肌动蛋白的活细胞成像、固定中的肌动蛋白细胞骨架分析细胞，肌动蛋白细胞骨架的电子显微镜，牵引力显微镜测量收缩强度平滑肌细胞，以及评估培养物中相关 mRNA 和蛋白质水平的几种分子方法内脏平滑肌。这些研究应该明确 ACTG2 R257C 如何导致破坏性平滑肌弱点并可能导致新的基于机制的治疗策略。特别是，定义的体外缺陷 ACTG2突变的潜在病理生理学将为高通量药物筛选提供平台发现 CIPO/MMIHS 的新疗法。

项目成果

期刊论文数量（2）

专著数量（0）

科研奖励数量（0）

会议论文数量（0）

专利数量（0）

Visceral myopathy: clinical syndromes, genetics, pathophysiology, and fall of the cytoskeleton.

内脏肌病：临床综合征、遗传学、病理生理学和细胞骨架的下降。

DOI：
发表时间：
2021
期刊：
影响因子：
0
作者：
Hashmi, Sohaib Khalid;Ceron, Rachel Helen;Heuckeroth, Robert O
通讯作者：
Heuckeroth, Robert O

Pseudo-obstruction-inducing ACTG2R257C alters actin organization and function.

诱导假性梗阻的 ACTG2R257C 会改变肌动蛋白的组织和功能。

DOI：
发表时间：
2020
期刊：
影响因子：
8
作者：
Hashmi, Sohaib Khalid;Barka, Vasia;Yang, Changsong;Schneider, Sabine;Svitkina, Tatyana M;Heuckeroth, Robert O
通讯作者：
Heuckeroth, Robert O