Circ-184-miR-34a-ULK1构成ceRNA网络激活胰腺星形细胞自噬抗胰腺纤维化机制研究

Chronic pancreatitis serves as progressive chronic inflammation in pancreas which is mainly characterized by pancreatic fibrosis, while the pathophysiological mechanism is still unclear. Autophagy functions as a protective mechanism for the maintenance of cellular homeostasis, and it participates in the evolution of multiple fibrotic diseases. The activation of pancreatic stellate cells plays the core role in pancreatic fibrosis, also the higher level of autophagy inhibits the activation of pancreatic stellate cells and slows the process of pancreatic fibrosis. In our previous study, the transcriptome sequenceing results revealed that 15 circular RNA, 21 miRNA and 330 mRNA were differential expression in the untreated and the activated groups. Bioinformatics analysis suggested that the competing endogenous RNA network composed by circ-184-miR-34a-ULK1, served as a significant role in pancreatic stellate cells activation. Unc-51 like kinase acts as a critical autophagic gene, participating in the initiation of autophagy. On the basis of this study, the co-expression network analysis would be completed in human tissues and the overexpression and silencing of circ-184, miR-34a and ULK1 would be carried out in vitro and in vivo. Depending on all above studies and experiments, we attempt to elucidate the main mechanism on activating autophagy and inhibiting pancreatic stellate cells activation and pancreatic fibrosis. Briefly, we aim to interpret the etiology of chronic pancreatitis and restrain the progression of pancreatic fibrosis, even to provide experimental basis for the targeted therapeutic drugs development. Our study opens evenbroader horizon prospects for further projects.

慢性胰腺炎（CP）是以胰腺纤维化为主要特征的进行性胰腺慢性炎症，其发生机制尚未阐明。自噬作为维持细胞稳态的保护机制，参与多种疾病纤维化演进。胰腺星形细胞（PSC）作为胰腺纤维化进程中的核心部分，其自噬水平升高可抑制细胞活化及胰腺纤维化。本课题组利用转录组测序，筛选出与PSC细胞活化相关的15个circRNA、21个miRNA及330个mRNA，生物信息预测提示，由circ-184-miR-34a-ULK1构成的ceRNA网络对PSC细胞活化发挥关键作用。ULK1作为自噬关键基因，诱发自噬的起始。本研究拟在此基础上，借助大量临床样本完成circ-184、miR-34a及ULK1的共表达分析，同时，在细胞及动物模型中，利用过表达及功能缺失研究，深入探讨该ceRNA网络激活自噬抑制PSC细胞活化及胰腺纤维化的关键性机制。为推动CP病因学研究、延缓病情进展及开发靶向治疗药物，提供广阔的思路与空间。

慢性胰腺炎（chronic pancreatitis，CP）以胰腺纤维化为主要临床特征，终将导致胰腺内外分泌功能不全，严重影响病人生活质量，目前，尚无有效手段延缓胰腺纤维化进程。胰腺星形细胞（pancreatic stellate cell，PSCs）作为参与胰腺纤维化最重要的细胞亚群，其受到炎症因子、外伤及酒精等刺激，能够从静息水平转变为活化状态，通过释放纤维化相关蛋白α-SMA、胶原蛋白、粘连蛋白等，促进胰腺纤维化进展。前期研究已证实，自噬是介导PSCs活化的重要生物学过程，但目前对其机制的研究较少。本研究基于转录组测序技术，通过比较静息与活化PSCs中差异表达基因，发现个差异基因可能参与PSCs活化，进一步筛选发现，RB1CC1在活化的PSCs中显著上调，推测其介导的PSCs活化可能在胰腺纤维化过程中发挥重要作用。为了深入探究RB1CC1介导PSCs活化的可能机制，我们对差异基因进行功能学进行预测，发现其可能通过调控ULK1复合物激活自噬，促进PSCs活化及胰腺纤维化。本研究借助临床样本、体外实验及CP小鼠模型等，系统揭示了RB1CC1靶向结合ULK1，一方面，通过抑制ULK1转录降低其表达水平；另一方面，通过蛋白互作促进其去磷酸化。上述过程最终导致PSCs自噬激活，促进PSCs活化及胰腺纤维化。研究结果提示RB1CC1可作为评估CP病人胰腺纤维化程度重要的分子靶标，基于RB1CC1的靶向自噬疗法可能为改善目前胰腺纤维化难以逆转的局面提供一定的思路。