Adipose FHL1 in energy homeostasis

脂肪 FHL1 在能量稳态中的作用

基本信息

批准号：
10717734
负责人：
Frederick Anokye-Danso
金额：
$ 47.32万
依托单位：
JOHNS HOPKINS UNIVERSITY
依托单位国家：
美国
项目类别：
财政年份：
2023
资助国家：
美国
起止时间：
2023-09-06 至 2028-08-31
项目状态：
未结题

来源：
https://reporter.nih.gov/project-details/10717734
关键词：
15 year old Adipocytes Adipose tissue Agreement Amino Acid Substitution Animal Model Applications Grants Attention Attenuated Biochemistry Biological Process Biology Bypass Cardiomyopathies Case Study Cell Differentiation process Cell model Cells Cellular biology Compensation Data Development Elements Energy Metabolism Enzymes Exhibits FHL1 gene FHL2 gene Fibroblasts Functional disorder Gene Expression Genes Goals High Fat Diet Homeostasis Human Hypertrophy Impairment In Vitro Incidence Investigation Knock-out Knockout Mice LIM Domain Link Luciferases Mediating Mediator Metabolic Metabolic Diseases Metabolism Mitotic Cell Cycle Molecular Molecular Biology Mus Muscle Muscular Dystrophies Myocardium N-terminal Obesity Pathogenesis Pathway interactions Patients Phenotype Physiological Positioning Attribute Principal Investigator Protein Family Protein Isoforms Proteins Regulation Reporting Research Research Personnel Resistance Role Serine Signal Transduction Skeletal Muscle Transcriptional Regulation Tryptophan Vertebral column adipocyte differentiation adipokines blood glucose regulation boys diet-induced obesity energy balance experimental study glucose metabolism in vivo in vivo evaluation insight insulin sensitivity knock-down lipid biosynthesis lipid metabolism loss of function member metabolic phenotype mouse model novel novel therapeutic intervention novel therapeutics older patient overexpression paralogous gene postnatal protein protein interaction subcutaneous transcription factor transplant model

项目摘要

SUMMARY Tremendous advances have been made in the study of adipose biology but there are gaps in our understanding of adipose development and functions. The long-term goal of our research is to understand how adipose tissues regulate whole-body energy metabolism, insulin sensitivity and glucose homeostasis. To achieve these goals, we have developed cellular and animal models to study the effects of gene perturbations in relation to adipose tissues development. One such gene is Four-and-half-LIM domain 1 (FHL1), a protein highly expressed in skeletal and cardiac muscles, and has recently been implicated in human adipose tissue development. A case report on a 15-year old patient with a complete deletion of FHL1 with adjacent MAP7D3 gene exhibited a near total loss of adipose tissues accompanied by muscular hypertrophy, rigid spine and short stature. The specific role of FHL1 in adipose development and function is unknown. In preliminary experiments, we identified FHL1 as a major co-transcription factor of PPARg, suggesting a role in transcriptional regulation of adipose tissues. To mimic the loss of adipose tissues in the human patient, we created a mouse model where FHL1 is globally deficient. Whole body Fhl1 knockout mice were resistant to diet-induced obesity (DIO). Interestingly, a previous study has shown that mice lacking a related paralog, FHL2, are also resistant to DIO. We found that FHL1 deficiency in murine preadipocytes partially attenuated differentiation into adipocytes, and a single amino acid substitution from tryptophan to serine at position 122 within FHL1 specifically abrogated PPARg isoform 2 (PPARg2) expression, but not isoform 1 (PPARg1). In agreement, knockdown of FHL1 in human adipocytes preferentially reduced PPARg2 expression, but not PPARg1. It has been reported that PPARg2 is adipose- specific, necessary and sufficient in activation of adipogenesis in fibroblast. In addition to activation of PPARg, FHL1 cooperates with PPARg in activation of PPARg-dependent gene expression. Based on our preliminary data, we hypothesized that FHL1 regulates adipocyte differentiation, at least in part, through transcriptional regulation of PPARg. This proposal seeks to investigate the cellular, molecular and physiological mechanisms by which FHL1 regulates adipose tissue development and energy homeostasis. Specific Aim 1 will examine the roles of FHL1 and FHL2 in murine adipocyte differentiation. Specific Aim 2 will address the underlying molecular mechanisms linking FHL1 and transcriptional regulation of adipocyte differentiation. Specific Aim 3 will investigate the in vivo functions of FHL1 in adipose-specific knockout mice and in human transplant models. Together, the proposed experiments will provide mechanistic insights into adipose biology, pathophysiology of obesity, potentially lead to novel therapeutic strategies for obesity and related metabolic diseases.

概括脂肪生物学研究已取得巨大进展，但我们的理解仍存在差距脂肪的发育和功能。我们研究的长期目标是了解脂肪组织如何调节全身能量代谢、胰岛素敏感性和葡萄糖稳态。为了实现这些目标，我们开发了细胞和动物模型来研究基因扰动对脂肪的影响组织发育。其中一个基因是四半 LIM 结构域 1 (FHL1)，这是一种在骨骼肌和心肌，最近还与人类脂肪组织的发育有关。一个案例一名 15 岁患者的报告显示 FHL1 及其邻近的 MAP7D3 基因完全缺失脂肪组织完全丧失，伴有肌肉肥大、脊柱僵硬和身材矮小。具体的 FHL1 在脂肪发育和功能中的作用尚不清楚。在初步实验中，我们鉴定出FHL1 作为 PPARg 的主要共转录因子，表明在脂肪组织的转录调节中发挥作用。到为了模拟人类患者脂肪组织的损失，我们创建了一个小鼠模型，其中 FHL1 全局存在缺乏。全身 Fhl1 基因敲除小鼠对饮食诱导的肥胖 (DIO) 具有抵抗力。有趣的是，之前的一个研究表明，缺乏相关旁系同源物 FHL2 的小鼠也对 DIO 具有抵抗力。我们发现FHL1 小鼠前脂肪细胞的缺乏部分减弱了脂肪细胞的分化，并且单一氨基酸 FHL1 内第 122 位色氨酸替换为丝氨酸，特异性消除了 PPARg 同工型 2 (PPARg2) 表达，但不是异构体 1 (PPARg1)。一致认为，人脂肪细胞中 FHL1 的敲低优先降低 PPARg2 的表达，但不降低 PPARg1 的表达。据报道，PPARg2 具有脂肪调节作用。成纤维细胞脂肪生成激活中的特异性、必要性和充分性。除了激活 PPARg 外， FHL1 与 PPARg 协同激活 PPARg 依赖性基因表达。根据我们的初步数据，我们假设 FHL1 至少部分通过转录调节来调节脂肪细胞分化 PPARg。该提案旨在研究细胞、分子和生理机制 FHL1 调节脂肪组织发育和能量稳态。具体目标 1 将研究以下角色的作用： FHL1 和 FHL2 在小鼠脂肪细胞分化中的作用。具体目标 2 将解决潜在的分子问题连接 FHL1 和脂肪细胞分化转录调控的机制。具体目标 3 将研究 FHL1 在脂肪特异性敲除小鼠和人体移植模型中的体内功能。总之，所提出的实验将为脂肪生物学、病理生理学提供机制见解。肥胖，可能会导致肥胖和相关代谢疾病的新治疗策略。