Sox9对皮脂腺细胞增殖与分化的调控机制研究

Sox9 is pivotal in the morphogenesis of hair follicles and sebaceous glands, but its role in sebocyte (SC) proliferation and differentiation is poorly understood. We have found that Sox9 was mainly expressed in the peripheral zone cells of normal sebaceous glands, Sox9 expression was upregulated in the acne lesions, and overexpression or knockdown of Sox9 resulted in the increase or decrease of sebum secretion. The above results suggest that Sox9 expression may be related to SC differentiation, sebum secretion and acne genesis, but its modulatory mechanism is unknown. We speculate that Sox9 might directly regulate the downstream target genes or via interacting with other transcript factors, thereby playing an important role in SC proliferation and differentiation. This project is about to do the following experiments using primarily cultured human SCs: (1) to screen the downstream target genes with differential expression by whole-genome chip and to verify them after transfected with overexpression or knockdown of Sox9 using adenoviral transfection; (2) to determine the change of the target genes with differential expression and to screen the differentiation markers during the different stages after establishing SC differentiation models (stem cells and proliferative and differentiated SCs), and to observe the effects of the target genes on SC differentiation and sebum secretion using adenoviral transfection. These results will unravel the regulatory role of Sox9 in SC proliferation and differentiation, lay the foundation for elucidating the pathogenesis of sebaceous gland-associated disorders, and provide novel targets for drug development.

Sox9在毛囊和皮脂腺形态发生中起主要作用，但其在皮脂腺细胞（SC）增殖与分化中作用了解甚少。我们已发现Sox9主要表达在正常皮脂腺周边区细胞，痤疮皮损中Sox9表达上调，过表达或敲低Sox9分别促进或减少皮脂分泌；提示Sox9表达与SC分化、皮脂分泌和痤疮发病有密切关系，但其调控机制不明。我们推测Sox9可能直接或通过与其它转录因子交互作用来调控下游靶基因，从而在SC增殖与分化中扮演重要角色。本项目拟用原代培养人SC进行下述实验：①Sox9过表达或敲低的腺病毒转染SC，用全基因组芯片筛选差异表达的Sox9下游靶基因并予以验证；②构建SC分化模型（干细胞、增生及分化SC），验证差异表达靶基因在不同分化阶段中表达、筛选分化标志物，并通过腺病毒转染观察靶基因对SC分化和皮脂分泌影响。研究结果将揭示Sox9对SC增殖与分化调控机制，为阐明皮脂腺相关疾病发病机制奠定基础并为药物开发提供新靶点。

Sox9在毛囊的形态发生中起重要作用，但其在皮脂腺的表达了解甚少。我们前期研究发现Sox9主要表达在正常皮脂腺周边区细胞，痤疮皮损中Sox9表达上调，过表达或敲低Sox9分别促进或减少皮脂分泌，提示Sox9表达与皮脂腺细胞（SC）分化、皮脂分泌和痤疮发病有密切关系，但其调控机制不明。我们进一步研究发现Sox9可能直接或通过与其它转录因子交互作用来调控下游靶基因，从而在SC增殖与分化中扮演重要角色。本项目应用原代培养人SC进行下述实验：①Sox9过表达或敲低的腺病毒转染SC，发现Sox9促进皮脂腺细胞增殖、分化和皮脂分泌；Sox9基因沉默可能通过阻滞G1/S过渡，诱导细胞凋亡和抑制皮脂腺细胞; iTRAQ筛选差异表达的Sox9下游靶基因,发现Sox9基因可以使157个蛋白表达上调，使56个蛋白表达下调；②构建SC分化模型（干细胞、增生及分化SC），电子显微镜以及流式细胞术验证模型的正确性，验证Sox9等相关SC分化靶基因在不同分化阶段中表达；iTRAQ筛选SC分化标志蛋白，发现在皮脂腺细胞分化过程中共有3582个蛋白表达，其中早期分化表达增多的有132个蛋白，中期分化有375个蛋白，晚期分化有96个蛋白；其中随皮脂腺细胞分化表达上调的转录因子FOXO1，Sox9可以表达调控FOXO1，我们通过FOXO1腺病毒转染再次观察FOXO1对SC分化和皮脂分泌有促进作用。研究结果揭示Sox9对SC增殖与分化起重要作用，可以通过调控相关蛋白参与皮脂腺细胞皮脂分泌，Sox9可以作为皮脂腺皮脂分泌相关疾病药物开发的新靶点。同时，通过iTRAQ筛选的SC分化标志蛋白，经过蛋白功能与调控机制研究后，均可以作为SC增生与分化以及皮脂调控的标准物，为研究痤疮发病机制以及治疗奠定实验基础。