Fetal Cell Senescence Signals Initiation of Parturition

胎儿细胞衰老标志着分娩的开始

• 批准号: 9276045
• 负责人: RAMKUMAR MENON
• 金额: $ 14.22万
• 依托单位: UNIVERSITY OF TEXAS MED BR GALVESTON
• 依托单位国家: 美国
• 财政年份: 2016
• 资助国家: 美国
• 起止时间: 2016-05-20 至 2021-03-31
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/9276045
• 关键词: Acetylation; Address; Affect; Aging; Amniotic Fluid; Apical; Area; B-Lymphocytes; Biochemistry; Biological; Biological Markers; Birth; Cell Aging; Cell Nucleus; Cell membrane; Cells; Chorion; Cytosol; Data; Diagnosis; Diffusion; Electron Microscopy; Encapsulated; Endosomes; Exocytosis; Feedback; Fetal Membranes; Fetal Tissues; Fetus; Flow Cytometry; Genes; Genetic Transcription; HMGB1 Protein; Human; Immune response; Immunoblotting; Inflammation; Inflammatory; Knowledge; Labor Onset; Lead; Liquid substance; MAP Kinase Gene; MAPK14 gene; Mediating; Metabolic; Molecular; Mothers; Muscle Cells; Myometrial; Organ Culture Techniques; Oxidants; Oxidative Stress; PTGS2 gene; Pathway interactions; Peripheral; Pharmacology; Phenotype; Physiological; Plasma; Pregnancy; Pregnancy Outcome; Pregnancy Tests; Premature Birth; Premature Labor; Premature aging syndrome; Process; Progesterone; Progesterone Receptors; Protein Isoforms; Proteins; Public Health; RNA Interference; Reaction; Recombinants; Research; Risk; Risk Factors; Role; Signal Transduction; Sterility; Stimulus; TLR2 gene; TLR4 gene; Term Birth; Testing; Tissues; Toll-like receptors; Up-Regulation; Venous; Vesicle; Withdrawal; aged; amnion; base; clinical material; cytokine; cytotrophoblast; exosome; experimental study; fetal; fetus cell; mitogen-activated protein kinase p38; myometrium; non-histone protein; novel; novel therapeutics; particle; prevent; progesterone receptor A; progesterone receptor B; public health relevance; receptor; response; senescence; therapy design; trophoblast

 DESCRIPTION (provided by applicant): Fetal cell senescence at term is a natural physiologic response to oxidative stress (OS) that occurs as a result of increased metabolic demands by the maturing fetus. Various risk factors for preterm labor are associated with OS-induced senescence. Our pilot data suggest that fetal cell senescence causes the alarmin HMGB1 (a non-histone protein) to translocate from the nucleus to the cytosol. There it is modified by acetylation and released via exocytosis ("free" HMGB1) or encapsulated in exosomes, (30-100 nm particles) formed and extruded by multivesicular endosome fusion with the plasma membrane. Secreted HMGB1 functions as a proinflammatory cytokine in feto-maternal tissues. In the fetal membranes, it augments fetal cell senescence and an associated 'sterile' inflammatory reaction through TLR2-mediated p38 MAPK activation. In myocytes, HMGB1 activates p38 MAPK, resulting in upregulation of progesterone receptor (PR) isoform A and increased COX-2 expression and myocyte inflammation. A positive OS feedback loop is also established by HMGB1, accelerating amniocyte aging. Our core hypothesis posits that HMGB1 secreted from senescing fetal membranes, either by diffusion or transported via exosomes, causes myometrial activation through p38 MAPK, which in turn increases the ratio of PR-A to PR-B, leading to functional progesterone withdrawal and triggering the onset of labor. This hypothesis will be tested in 2 specific aims. Specific Aim 1 will determine how OS stimulates fetal membrane cell-derived HMGB1 secretion, as free protein or packaged and exported in exosomes, during human pregnancy and parturition. Specific Aim 2 will determine how free- or exosome-HMGB1 produced by fetal membrane cells in response to OS induces functional progesterone withdrawal and myometrial contractility. Primary and transformed human amnion, chorionic trophoblast, and myometrial cells, as well as fetal membrane and myometrial organ cultures, will be exposed to OS-inducing agents. Using molecular and cellular biological approaches we will quantitate OS-induced fetal cell senescence, HMGB1 release, exosome packaging, direction of exosome-HMGB1 secretion, signaling via p38 MAPK, PR isoform switching, and myometrial activation. Additionally, we will quantify the concentrations of exosome-HMGB1 in our banked feto-maternal biologic fluids (amniotic fluid, peripheral and maternal uterine venous plasma, and fetal cord plasma) from term and preterm births (PTB) to correlate their distribution with defined pregnancy outcomes. This study will evaluate a new feto-maternal signaling mechanism that triggers parturition in response to fetal OS. Identification of novel pathways and biomolecules should provide new targets to screen, diagnose, and reduce the risk of PTB.

 描述（由申请方提供）：足月胎儿细胞衰老是对氧化应激（OS）的自然生理反应，是成熟胎儿代谢需求增加的结果。早产的各种危险因素与OS诱导的衰老有关。我们的试验数据表明，胎儿细胞衰老导致alarmin HMGB 1（一种非组蛋白蛋白）从细胞核易位到细胞质。在那里，它通过乙酰化修饰并通过胞吐作用释放（“游离”HMGB 1）或包封在外泌体（30-100 nm颗粒）中，外泌体通过多泡内体与质膜融合形成并挤出。分泌的HMGB 1在胎儿-母体组织中作为促炎细胞因子发挥作用。在胎膜中，它通过TLR 2介导的p38 MAPK激活增强胎儿细胞衰老和相关的“无菌”炎症反应。在肌细胞中，HMGB 1激活p38 MAPK，导致孕激素受体（PR）亚型A上调和考克斯-2表达增加和肌细胞炎症。HMGB 1还建立了一个积极的OS反馈回路，加速细胞老化。我们的核心假设是，从衰老的胎膜分泌的HMGB 1，无论是通过扩散还是通过外泌体转运，通过p38 MAPK引起子宫肌层激活，这反过来又增加了PR-A与PR-B的比例，导致功能性孕酮戒断并触发分娩的开始。这一假设将在2个具体目标中进行检验。具体目标1将确定在人类妊娠和分娩期间，OS如何刺激胎膜细胞来源的HMGB 1分泌，作为游离蛋白或包装并输出到外泌体中。具体目标2将确定如何自由或外泌体HMGB 1产生的胎膜细胞在OS诱导功能性孕酮撤退和子宫肌层收缩。将原代和转化的人羊膜、绒毛膜滋养层和子宫肌层细胞以及胎膜和子宫肌层器官培养物暴露于OS诱导剂。使用分子和细胞生物学方法，我们将定量OS诱导的胎儿细胞衰老，HMGB 1释放，外泌体包装，外泌体-HMGB 1分泌的方向，通过p38 MAPK，PR亚型转换和子宫肌层激活的信号传导。此外，我们将量化来自足月和早产（PTB）的我们库存的胎儿-母体生物液（羊水、外周和母体子宫静脉血浆和胎儿脐带血浆）中的外泌体-HMGB 1浓度，以将它们的分布与定义的妊娠结局相关联。本研究将评估一种新的胎儿-母体信号传导机制，该机制触发分娩以响应胎儿OS。新途径和生物分子的鉴定应提供新的靶点以筛选、诊断和降低PTB的风险。