Estrogen and Abdominal Muscle Fibrosis

雌激素与腹肌纤维化

• 批准号: 10546452
• 负责人: Serdar E. Bulun
• 金额: $ 59.54万
• 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 2025-01-31
• 项目状态: 未结题
• 来源: https://reporter.nih.gov/project-details/10546452
• 关键词: Abdominal Muscles; Ablation; Adjuvant Therapy; 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; 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; Proliferating; 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; Western Blotting; Wild Type Mouse; abdominal wall; antagonist; 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; 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.

虽然超过四分之一的男性可能会出现有症状的腹股沟疝，但其机制是 目前未知。由于肌肉纤维化和肌纤维萎缩，可能会发生一部分疝， 下腹壁无力本申请的长期目标是确定雌激素的作用 下腹部肌肉组织（LAMT）纤维化和萎缩的病因学中的作用， 腹股沟疝芳香化酶，将睾酮转化为雌二醇，仅在大脑和睾丸中表达 指雄性老鼠。然而，在男性中，芳香化酶在许多其他组织（肌肉，脂肪）中表达，以提供 生理上必需的局部雌激素量。我们用转基因的人源化芳香酶 （Aromhum）小鼠系，每一个含有全长人芳香化酶基因的单拷贝，包括其 调节区，以模仿人类雌激素产生的模式。Aromhum小鼠表达芳香化酶基因 包括骨骼肌组织的成纤维细胞成分的外周组织中。已发现LAMT 比上腹部或四头肌对雌二醇更敏感，因为LAMT的基质 含有大量的雌激素受体β（ER β）表达的成纤维细胞。局部增加 LAMT中雌二醇浓度与LAMT纤维化相关，其特征在于进行性 用富含ER β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24周时在>90%的Aromhum雄性小鼠中形成大的腹股沟疝。但 在任何野生型（WT）同窝仔中均未观察到疝。LAMT基因表达谱分析 四周（在疝出现之前）显示在Aromhum与WT小鼠中激活的促纤维化途径。 我们假设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， 肌细胞萎缩，导致疝表型，影响骨骼肌对雌激素高度敏感的部分， 肌肉组织，这是Aromhum小鼠的LAMT。与此同时， 老年男性腹股沟疝发病率及骨骼肌和脂肪中芳香化酶表达增加。到 在确定潜在机制的基础上，我们提出了以下目标：1。确定是否使用 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 肌肉萎缩和疝形成。雌二醇/ER β介导的基因组机制 将使用以下方法确定导致成纤维细胞的无序增殖和细胞外基质形成的原因： 对LAMT和成纤维细胞RNA-seq和ER β-ChIP-seq的整合分析。2.确定是否 选择性破坏骨骼肌成纤维细胞中的ER β基因影响LAMT纤维化和疝形成 在Aromhum小鼠中。同时，我们将评估组织类固醇水平，芳香化酶和ER β表达，以及雌激素水平。 有或没有疝气的男性腹部肌肉活检中的反应基因。我们预计这部小说 该提案将确定新的药物靶点，并可能导致发现预防疝气的方法， 高危人群。