Elucidation of the hr-dependent pathway of hair growth

描述（摘自申请人摘要）：最近， 在理解毛囊（HF）的形态发生方面取得了进展 生物学;然而，毛发生长控制的分子和遗传方面 仍然在很大程度上未知。其中，HF退行期的分子途径 尽管存在异常， 退化期进展是人类许多常见毛发疾病的基础。最近 研究表明，退化期是一个由细胞增殖驱动的过程， 死亡是退化期HF转化的主要机制。以前的研究 表明HF基质中的异位和过早凋亡是主要缺陷 在突变型hr/hr无毛小鼠皮肤中，导致毛发完全脱落。 这些发现暗示了无毛基因是一个关键因素， HF退化期的基本细胞过程和程序性细胞死亡， hr基因活性的可能关键靶点。为了进一步了解 通过hr对HF功能的分子控制，他们建议使用天然的 皮肤和培养的角质形成细胞来源于突变体（hrrh/hrrh）无毛 小鼠作为研究hr基因在调节细胞凋亡中作用的模型 代谢驱动的退行期和下游靶标的鉴定 HR基因的活性。hr基因参与细胞凋亡的假说 将使用形态学方法、TUNEL和 膜联蛋白V染色沿着功能实验（比较 UVB下开始时，以hr/hr和wt表示的凋亡相关基因表达 照射，用DFMO和ICE以及半胱天冬酶-3抑制剂处理）。使用 北方印迹分析和免疫组化，他们将测试表达 依赖于HR的调节的假定下游靶点的模式 WT和HR/HR皮肤中的通路。hr基因未知靶点的寻找 将使用具有核酸的杂交阵列进行活性 分离自HRRH/HRRH和WT基因型的完整小鼠表皮。 将根据已知的候选靶基因对所鉴定的候选靶基因进行优先排序。 在毛囊生理学中的作用，并且还根据从 功能实验和免疫组织化学研究。因此，实验 在这项建议中概述的是旨在解剖细胞和分子 使用无毛表型的毛囊退化期转化的机制 作为实验模型。

DESCRIPTION (Taken from the applicant's abstract): Recently, progress has been achieved in the understanding of the morphogenic aspects of hair follicle (HF) biology; nevertheless, the molecular and genetic aspects of hair growth control remain largely unknown. Among these, the molecular pathways of HF catagen transformation are the least well understood despite the abnormalities of catagen progression underlie many common hair disorders in humans. Recent studies showed that catagen is an apoptosis-driven process and programmed-cell death is the major mechanism of catagen HF transformation. Previous studies indicated that ectopic and premature apoptosis in HF matrix is the major defect in the mutant hr/hr hairless mouse skin that causes the complete hair loss. These findings implicate the hairless (hr) gene as a key factor in coordinating basic cellular processes during HF catagen and programmed cell death as a possible key target of hr gene activity. In order to gain further insights into the molecular control of HF functions by hr, they propose the use of the native skin and cultured keratinocytes derived from the mutant (hrrh/hrrh) hairless mice as a model for elucidation the role of hr gene in regulation of apoptosis-driven catagen and for the identification of the downstream targets of hr gene activity. The hypothesized involvement of hr gene into apoptotic regulatory pathway will be tested using morphological methods, TUNEL and annexin V staining along with functional experiments (comparison of apoptosis-associated gene expression in hr/hr and wt start under UVB irradiation, treatment with DFMO and ICE and caspase-3 inhibitors). Using Northern blot analysis and immunohistochemistry, they will test the expression patterns of presumptive downstream targets of the hr-dependent regulatory pathway in wt and hr/hr skin. The search for unknown targets of hr gene activity will be performed using hybridization arrays with nucleic acids isolated from intact mouse epidermis of both hrrh/hrrh and wt genotypes. Identified candidate target genes will be prioritized according to their known role in hair follicle physiology, and also according to data obtained from functional experiments and immunohistochemical studies. Thus, the experiments outlined in this proposal are designed to dissect the cellular and molecular mechanisms of hair follicle catagen transformation using the hairless phenotype as an experimental model.