摘要:哺乳動物細胞可感應缺氧(hypoxia)環境來與適應周遭氧氣濃度的減少,動物體細胞的生存端賴循環系統的血液來供給所需的氧氣及養份,因此,動物細胞在缺氧環境的變化下將會啟動特異基因來應付環境的缺氧,例如在正常生理發育下,胚胎發育時的血管新生以及病理上腫瘤形成的過程中。而在細胞適應缺氧的調節路徑中有一個缺氧轉錄因子(HIFs)扮演著重要的角色,HIFs 蛋白的活性會隨著氧氣分子的減少而增加,進而誘發下游基因表現來調
控細胞甚而整個器官的功能來適應缺氧所造成的緊迫(stress)。雌性動物卵巢已是提供生理上血管新生的一個極有價值的研究模式,而缺氧緊迫常發生在卵巢發育時濾泡的生長與黃體的形成過程,且濾泡或黃體的生長都需要新生的血管來提供其內泌素、氧氣及營養。現今已知黃體組織是體內血
Abstract: Mammalian cells are able to sense prolonged decrease in oxygen concentration (hypoxia)through a conserved hypoxia response pathway. This pathway facilitates adaptation to hypoxia-induced physiological stress by regulating changes in gene expression and is critical for the execution of many physiological events, including formation of blood vessels during embryogenesis and patho-physiological processes such as tumorogenesis. A family of hypoxia-inducible transcription factor (HIFs) lies at the key point of this adaptive pathway. HIFs proteins are activated by decrease in the concentration of molecular oxygen (O2), which results in the induced expression of downstream target genes that mediate adaptation and survival of cells and the whole organism. A valuable model to study the physiological pattern of the angiogenic process in the adult is offered by the ovary in the female reproductive system. In particular, the ovary is unique since it represents a site of hypoxia stress that take place both during the growing follicle and corpus luteum formation phase. The vasculature of follicle and corpus luteum is necessary for supplying hormones and their precursor, oxygen and nutrients. It is known fact that corpus luteum receives the greatest rate of blood flow per unit of tissue of any organ in the body, hence is critical to hypoxic conditions. Until now, there is very limited information on the relationship among HIFs and its target genes during ovary development. Intending to reveal the underlying mechanism, we attempt to test the effects of hypoxia condition on the main parameters of granulosa and luteal cell functions, steroidogenesis, cell proliferation, and cell apoptosis, and gene regulation in the ovarian tissues.
In this study, we intend to use molecular and cell physiological approaches to study gene
regulatory mechanism of hypoxia stress during ovary development. The propose of the study
is to provide molecular evidence on the genes involved in cell differentiation, proliferation,
apoptosis and steroidogenesis with relation to hypoxia stress during ovarian development.
Therefore, this research is designed with a three years plan of study and the bovine ovary as
the choice of research model. In the first year, the healthy bovine ovary will be selected for
tissue section experiments. The molecular markers of cell differentiation, proliferation,
apoptosis and steroidogenesis will be checked by I.H.C. technique. In the second year,
using in vitro techniques we intend to examine the hypoxia stress responsiveness. By doing
so, we attempt to understand the molecular mechanism of growth, differentiation, apoptosis
and steroidogenesis in granulosa and luteal cells by different hypoxia condition. In the third
year, we will try to elucidate the role of HIFs in CLC-D cell line proliferation, apoptosis and
steroidogenesis. Using molecular biological techniques (over expression or RNAi) we intend
to investigate the physiol