Fetal HCMV Infection: Role of the Human Placenta

描述(申请人提供)：原发母体人类巨细胞病毒(HCMV)感染影响1-3%的妊娠，并导致25%的先天性感染婴儿的出生缺陷。胎盘因炎症、水肿、缺氧和纤维化而受损。人巨细胞病毒在蜕膜(母体)细胞、胎盘(胎儿)细胞滋养层(CTB)和血管中复制，绒毛呈进行性水肿性减少血液灌注量。胎盘-胎儿单位积液也表明蜕膜淋巴管清除多余液体的能力减弱。子宫中的直接感染或旁分泌效应如何会损害淋巴功能尚不清楚。初步研究表明，人巨细胞病毒可在淋巴管内皮细胞(LEC)中复制，并在体外调节分化和迁移。重要的是，在先天性感染胎盘的蜕膜中发现了受感染的淋巴管。为了研究胎盘形成的分子机制，我们建立了一种新的人胎盘模型，将人胎盘绒毛(胎儿)和蜕膜(母体)异种移植到严重联合免疫缺陷(SCID-HU)小鼠体内。胎儿CTB分化并诱导淋巴管生成，形成新的淋巴管，类似于人类蜕膜中的淋巴管。我们发现一种致病的巨细胞病毒毒株在胎盘绒毛和蜕膜植入物的CTB中复制，淋巴管生成受损。感染CTB后上调的血管内皮生长因子A和C(VEGF-A/C)对体内LEC功能有旁分泌作用。我们的主要假设是，HCMV通过(1)直接感染蜕膜淋巴管和(2)妊娠子宫胎盘CTB(胎儿)和蜕膜细胞(母体)分泌的生长因子和细胞因子的旁分泌作用来损害淋巴管的生成。具体目标如下。目的1.研究人巨细胞病毒直接感染蜕膜上皮细胞，以确定整合素失调节的分子途径，整合素作为趋化、迁移和脐带形成的下游效应因子发挥作用。目的2.研究人巨细胞病毒感染胎盘CTB中血管内皮生长因子相关蛋白的旁分泌作用。检测SCID-Hu小鼠胎盘绒毛异种移植中淋巴管生成失调的因素。目的3.研究母体蜕膜成纤维细胞感染对淋巴管生成的影响。研究人巨细胞病毒感染的异种蜕膜组织移植物和SCID-Hu小鼠体内的旁分泌因子。我们的假设的证实将直接与临床应用新的治疗方法相关，以防止妊娠期间的胎盘浮肿，使用抗体或小分子来阻断旁分泌因子和炎性细胞因子。这些可以与生物治疗抗体一起应用于临床，这些抗体可以抑制HCMV复制，防止胎盘功能障碍，并提高健康婴儿的机会。 与公共卫生相关：识别受感染的淋巴管内皮细胞功能受损的分子机制，以及受感染的胎盘(胎儿)和蜕膜(母体)细胞分泌因子的分子机制，可能导致新的临床干预措施，以防止先天性感染引起的胎盘水肿和相关的妊娠并发症。

DESCRIPTION (provided by applicant): Primary maternal human cytomegalovirus (HCMV) infection affects 1-3% of pregnancies and causes birth defects in 25% of congenitally infected babies. The placentas are damaged from inflammation, edema, hypoxia, and fibrosis. HCMV replicates in decidual (maternal) cells, placental (fetal) cytotrophoblasts (CTB) and blood vessels, and the chorionic villi become progressively edematous reducing blood perfusion. Accumulation of fluid in the placental-fetal unit also suggests lymphatic vessels in the decidua have diminished capacity to remove excess fluid. How lymphatic functions could be impaired by direct infection or paracrine effects in utero is not known. Preliminary studies showed that HCMV replicates in lymphatic endothelial cells (LEC) and dysregulates differentiation and migration in vitro. Importantly, infected lymphatic vessels were found in the decidua of congenitally-infected placentas. To study the molecular mechanisms in vivo, we developed a novel model of human placentation in which xenografts of human placental villi (fetal) and decidua (maternal) are implanted in severe-combined immunodeficient (SCID-hu) mice. Fetal CTB differentiate and induce lymphangiogenesis, and new lymphatic vessels form like those in the human decidua. We showed that a pathogenic HCMV strain replicates in CTB of placental villi and decidual implants and that lymphangiogenesis was impaired. Vascular endothelial growth factors A and C (VEGF-A/C) upregulated in infected CTB could have paracrine effects on LEC functions in vivo. Our overarching hypothesis is that HCMV impairs lymphangiogenesis by (i) direct infection of decidual lymphatic vessels and (ii) paracrine effects of growth factors and cytokines secreted from placental CTB (fetal) and decidual cells (maternal) in the pregnant uterus. The specific aims are as follows. Aim 1. Study direct HCMV infection of decidual LEC to identify molecular pathways that dysregulate integrins that function as downstream effectors of chemotaxis, migration and cord formation. Aim 2. Study paracrine effects of VEGF-related proteins from HCMV-infected placental CTB (fetal). Examine factors that dysregulate lymphangiogenesis in placental villous xenografts in SCID-hu mice. Aim 3. Investigate cytokines from infected decidual fibroblasts (maternal) that affect lymphangiogenesis. Study paracrine factors in xenografts of decidual tissue infected with HCMV in explants and in SCID-hu mice. Confirmation of our hypothesis will be directly relevant to clinical applications of new treatments to prevent placental edema during pregnancy using antibodies or small molecules that block paracrine factors and inflammatory cytokines. These could have clinical application in conjunction with biotherapeutic antibodies that suppress HCMV replication, prevent placental dysfunction and improve chances for a healthy baby. PUBLIC HEALTH RELEVANCE: Identifying the molecular mechanisms that impair functions of infected lymphatic endothelial cells, and secreted factors from infected placental (fetal) and decidual (maternal) cells, could lead to new clinical interventions to prevent placental edema and associated pregnancy complications from congenital infection.