Fetal HCMV Infection: Role of the Human Placenta

描述（由申请人提供）：原发性母体人巨细胞病毒（HCMV）感染影响1-3%的妊娠，并导致25%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。HCMV在蜕膜（母体）细胞、胎盘（胎儿）细胞滋养层（CTB）和血管中复制，绒毛膜绒毛逐渐水肿，减少血液灌注。液体在胎盘-胎儿单位中的积聚也表明蜕膜中的淋巴管清除多余液体的能力减弱。子宫内直接感染或旁分泌效应如何损害淋巴功能尚不清楚。初步研究表明，HCMV在淋巴管内皮细胞（LEC）中复制，并在体外失调分化和迁移。重要的是，在先天性感染胎盘的蜕膜中发现了感染的淋巴管。为了研究体内的分子机制，我们开发了一种新的人胎盘形成模型，其中将人胎盘绒毛（胎儿）和蜕膜（母体）异种移植物植入严重联合免疫缺陷（SCID-hu）小鼠中。胎儿CTB分化并诱导淋巴管生成，并且新的淋巴管形成，如人蜕膜中的那些。我们发现，致病性HCMV株复制在CTB的胎盘绒毛和蜕膜植入和淋巴管生成受损。血管内皮生长因子A和C（VEGF-A/C）在感染CTB中上调，可能对体内LEC功能具有旁分泌作用。我们的总体假设是HCMV通过（i）直接感染蜕膜淋巴管和（ii）妊娠子宫中胎盘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损害淋巴管生成。具体目标如下。目标1.研究直接HCMV感染蜕膜LEC，以确定整合素失调的分子途径，整合素作为趋化性、迁移和索形成的下游效应物。目标2.研究HCMV感染的胎盘CTB（胎儿）中VEGF相关蛋白的旁分泌作用。检查SCID-hu小鼠胎盘绒毛异种移植物中淋巴管生成失调的因素。目标3.研究来自受感染的蜕膜成纤维细胞（母体）的影响淋巴管生成的细胞因子。研究旁分泌因子在HCMV感染的蜕膜组织异种移植物中的作用。证实我们的假设将直接关系到临床应用的新的治疗方法，以防止胎盘水肿在怀孕期间使用抗体或小分子阻断旁分泌因子和炎性细胞因子。这些可以与抑制HCMV复制，预防胎盘功能障碍和提高健康婴儿机会的双抗体结合使用。

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.