Estrogen and Abdominal Muscle Fibrosis

雌激素与腹肌纤维化

• 批准号: 9916751
• 负责人: Serdar E. Bulun
• 金额: $ 60.03万
• 依托单位: NORTHWESTERN UNIVERSITY AT CHICAGO
• 依托单位国家: 美国
• 财政年份: 2019
• 资助国家: 美国
• 起止时间: 2019-04-16 至 2024-01-31
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/9916751
• 关键词: Abdominal Muscles; Adjuvant; Affect; Aging; Appearance; Area; Aromatase; Aromatase Inhibitors; Atrophic; Bioinformatics; Biological; Biopsy; Brain; ChIP-seq; Combined Modality Therapy; Data; Development; Disease; Elderly man; Estradiol; Estradiol Antagonists; Estrogen Receptor alpha; Estrogen Receptors; Estrogens; Etiology; Extracellular Matrix; Fatty acid glycerol esters; Fibroblasts; Fibrosis; Fulvestrant; Genes; Genetic; Genomics; Hernia; Hernia of abdominal cavity; Human; Immunoblotting; Immunohistochemistry; Incidence; Infection; Inguinal Hernia; Intervention; Label; Lead; Length; Letrozole; Maps; Mediating; Messenger RNA; Modeling; Molecular; Mus; Muscle; Muscle Cells; Muscle Fibers; Muscle Weakness; Muscular Atrophy; Nucleic Acid Regulatory Sequences; Operative Surgical Procedures; Pain; Pathway Analysis; Pathway interactions; Patients; Pattern; Peripheral; Pharmacologic Substance; Phenotype; Physiological; Physiology; Population; Postoperative Pain; Prevalence; Preventive; Production; Proteins; Pyrazoles; RNA analysis; Recurrence; Refractory; Role; S100A4 gene; Signal Transduction; Skeletal Muscle; Steroids; Surgeon; Testis; Testosterone; Time; Tissues; Transgenic Organisms; United States National Institutes of Health; Wild Type Mouse; abdominal wall; clinically relevant; conditional knockout; estrogen disruption; estrogenic; experimental study; genetic signature; genome-wide; high risk population; histone modification; human disease; male; men; morphometry; mortality; mouse model; new therapeutic target; novel; postnatal; prevent; quadriceps muscle; receptor expression; repaired; skeletal muscle wasting; transcriptome; transcriptome sequencing

Although more than 1 in 4 men can be expected to develop symptomatic inguinal hernia, its mechanism is currently unknown. A subset of hernias may develop due to muscle fibrosis and myofiber atrophy leading to lower abdominal wall weakness. The long-term objective of this application is to determine the role of estrogen action in the etiology of lower abdominal muscle tissue (LAMT) fibrosis and atrophy associated with a subset of inguinal hernias. Aromatase, which converts testosterone to estradiol, is expressed only in the brain and testes of male mice. However, in men, aromatase is expressed in many additional tissues (muscle, fat) to provide physiologically necessary local quantities of estrogen. We generated transgenic humanized aromatase (Aromhum) mouse lines, each containing a single copy of the full-length human aromatase gene including its regulatory region, to mimic human patterns of estrogen production. Aromhum mice express the aromatase gene in peripheral tissues including the fibroblast component of the skeletal muscle tissue. LAMT has been found to be more sensitive to estradiol than the upper abdominal or quadriceps muscles, because the stroma of LAMT contains strikingly larger amounts of estrogen receptor- (ER)-expressing fibroblasts. Locally increased concentrations of estradiol in LAMT was associated with LAMT fibrosis characterized by progressive replacement of atrophic myocytes (muscle fibers) with ER-rich fibroblasts and excessive extracellular matrix, resulting in formation of large inguinal hernias in >90% of Aromhum male mice by 24 weeks. However, there were no hernias observed in any of the wild-type (WT) littermates. Microarray expression analysis of LAMT at four weeks (before the appearance of hernias) showed activated profibrotic pathways in Aromhum vs. WT mice. We hypothesize that enhanced estrogen action caused by locally formed estradiol drives muscle fibrosis and myocyte atrophy, leading to the hernia phenotype affecting highly estrogen-sensitive portions of skeletal muscle tissue, which is LAMT in Aromhum mice. This resonates with the remarkable and parallel increases in inguinal hernia incidence and increased aromatase expression in skeletal muscle and fat in aging men. To ascertain the underlying mechanisms, we propose the following aims: 1. Determine whether treatment with an aromatase inhibitor, an estradiol antagonist, or a highly selective ERα antagonist prevents fibrosis, LAMT muscle atrophy, and hernia formation in Aromhum mice. The estradiol/ER-mediated genomic mechanisms responsible for disordered proliferation of fibroblasts and extracellular matrix formation will be determined using integrative analysis of RNA-seq and ER-ChIP-seq on LAMT and fibroblasts. 2. Determine whether the genetic disruption of ER selectively in skeletal muscle fibroblasts affects LAMT fibrosis and hernia formation in Aromhum mice. In parallel, we will assess tissue steroid levels, aromatase and ERexpression, and estrogen responsive genes in abdominal muscle biopsies of men with or without hernia. We anticipate that this novel proposal will identify new drug targets and likely lead to the discovery of preventive approaches for hernia in high-risk populations.

尽管预计超过四分之一的男性会出现有症状的腹股沟疝气，但其机制是 目前尚不清楚，一部分疝气可能是由于肌肉纤维化和肌纤维萎缩导致的。 本应用的长期目标是确定雌激素的作用。 与一部分相关的下腹部肌肉组织（LAMT）纤维化和萎缩的病因学作用 腹股沟疝气，将睾酮转化为雌二醇，仅在大脑和测试中表达。 然而，在雄性小鼠中，芳香酶在许多其他组织（肌肉、脂肪）中表达，以提供芳香酶。 我们产生了转基因人源化芳香酶。 (Aromhum) 小鼠品系，每个品系均含有全长人类芳香酶基因的单个拷贝，包括其 调节区，模仿人类雌激素产生模式，Aromhum 小鼠表达芳香酶基因。 已发现 LAMT 存在于外周组织（包括骨骼肌组织的成纤维细胞成分）中。 比上腹部或股四头肌对雌二醇更敏感，因为 LAMT 的基质 含有显着大量的表达雌激素受体-α (ERα) 的成纤维细胞。 LAMT 中雌二醇的浓度与 LAMT 纤维化相关，其特征是进行性 用富含 ERα 的成纤维细胞和过量的细胞外基质替代萎缩的肌细胞（肌纤维）， 导致超过 90% 的 Aromhum 雄性小鼠在 24 周内形成大腹股沟疝气。 在任何野生型（WT）同窝小鼠中均未观察到疝气。 四周（疝气出现前）显示 Aromhum 与 WT 小鼠的促纤维化途径被激活。 我们努力奋斗，局部形成的雌二醇引起的雌激素作用增强会导致肌肉纤维化和 肌细胞萎缩，导致疝表型影响骨骼中对雌激素高度敏感的部分 肌肉组织，即 Aromhum 小鼠的 LAMT，这与 Aromhum 小鼠的显着且平行的增加产生共鸣。 老年男性腹股沟疝气的发病率以及骨骼肌和脂肪中芳香酶表达的增加。 为了确定潜在机制，我们提出以下目标： 1. 确定是否采用 芳香酶抑制剂、雌二醇拮抗剂或高选择性 ERα 拮抗剂可预防纤维化、LAMT Aromhum 小鼠肌肉萎缩和疝气形成 雌二醇/ERα 介导的基因组机制。 导致成纤维细胞增殖紊乱和细胞外基质形成的原因将通过使用确定 RNA-seq 和 ERα-ChIP-seq 对 LAMT 和成纤维细胞的综合分析 2. 确定是否。 骨骼肌成纤维细胞中 ERα 的基因选择性破坏影响 LAMT 纤维化和疝气形成 同时，我们将评估 Aromhum 小鼠的组织类固醇水平、芳香酶和 ERα 表达以及雌激素。 我们预计，患有或不患有疝气的男性腹部肌肉活检中的反应基因。 该提案将确定新的药物靶标，并可能导致发现疝气的预防方法 高危人群。