TRANSCRIPTIONAL REGULATION OF CERVICAL COMPETENCE DURING PREGNANCY

预防早产的大部分困难在于我们不了解是什么控制了妇女的分娩时间。直到最近，子宫颈一直被认为只是一个被动的角色，在怀孕期间保持关闭，只是在分娩期间其直径呈指数级增加到10厘米或更大。然而，现在很清楚，在孕中期子宫颈缩短是早产的早期预测因素，这表明子宫颈变化发生在早产子宫收缩前几周。因此，需要了解调节宫颈功能进行性变化的细胞和分子机制，以影响早产率。作为我们总体目标的一部分， 为了研究妊娠期间子宫颈功能的转录调控，转录因子小眼症相关转录因子（MITF）被鉴定为来自子宫颈未成熟的足月妇女和子宫颈扩张和消失的足月妇女的子宫颈组织中的差异调节基因。在随后的实验中，我们确定了一种新的亚型MITF在女性生殖道，并发现显着减少这种亚型在子宫颈组织的妇女在劳动。这些结果，连同显着的分娩表型的MITF突变纯合子小鼠，提供了目前的假设，即MITF是一个重要的转录调节子宫颈的能力在怀孕期间的基础。为了验证这一假设，我们提出：（1）确定组织和亚型特异性表达的 本发明的目的在于：（1）确定妊娠期间和产后期间子宫颈和子宫肌层中的MITF，（2）确定子宫颈基质细胞中MITF调节的靶基因，和（3）确定子宫和子宫颈的基质细胞和平滑肌细胞中MITF基因表达的调节剂。将利用培养的人宫颈组织和细胞来确定MITF及其调节的细胞靶点。将使用野生型和突变型mi/mi小鼠研究该因子在妊娠期间的生理作用。最后，孕激素受体和孕激素诱导的信号转导通路对MITF基因表达和妊娠期宫颈功能的影响将进行评估。拟议的研究不仅将回答有关以下方面的重要问题 本研究不仅有助于了解宫颈重塑和分娩的启动机制，而且还将通过转录因子MITF深入了解宫颈功能的生理调节。预计了解这些基本机制和MITF的基因靶点将导致治疗策略的发展，以预防或消除宫颈机能不全，宫颈早熟和劳动。

Much of the difficulty in preventing preterm birth resides in the fact that we do not understand what controls the timing of parturition in women. Until recently, the cervix has been credited with little more than a passive role, remaining closed during pregnancy only to exponentially increase its diameter to 10 cm or more during labor. It is now clear, however, that shortening of the cervix in the second trimester is an early predictor of preterm birth, suggesting that cervical changes occur several weeks prior to uterine contractions of preterm labor. Thus, an understanding of the cellular and molecular mechanisms that regulate progressive changes in cervical function are needed to impact the preterm birth rate. As part of our overall goal to understand the transcriptional regulation of cervical function during pregnancy, the transcription factor microphthalmia-associated transcription factor (MITF) was identified as a differentially-regulated gene in cervical tissues from women at term with an unripe cervix and women at term with cervical dilation and effacement. In subsequent experiments, we defined a novel isoform of MITF in the female reproductive tract and found dramatic decreases in this isoform in cervical tissues from women in labor. These results, together with the striking parturition phenotype of mice homozygous for mutations in MITF, provide the foundation for the current hypothesis, namely that MITF is an important transcriptional regulator of cervical competence during pregnancy. To test this hypothesis, we propose: (1) To determine tissue- and isoform-specific expression of MITF in cervix and myometrium during pregnancy and the postpartum time period, (2) to identify target genes of MITF regulation in cervical stromal cells, and (3) to identify regulators of MITF gene expression in stromal and smooth muscle cells of the uterus and cervix. Human cervical tissues and cells in culture will be utilized to define the cellular targets of MITF and its regulation. Wild type and mutant mi/mi mice will be used to study the physiologic role of this factor during pregnancy. Finally, the impact of progesterone receptor- and cytokine-induced signal transduction pathways on MITF gene expression and cervical function during pregnancy will be evaluated. The proposed studies will not only answer important questions regarding mechanisms in the initiation of cervical remodeling and labor, but will also provide insight into the physiologic regulation of cervical competence through the transcription factor MITF. It is anticipated that understanding these basic mechanisms and the gene targets of MITF will lead to the development of therapeutic strategies to prevent or abrogate cervical incompetence, preterm cervical ripening, and labor.