自噬性非经典分泌途径对银屑病免疫微环境的调控作用及分子机制研究

Psoriasis is a common autoimmune disease with serious harm to the human physical and mental health. Keratinocytes (KCs) play an important role in immune regulation of psoriasis immune microenvironment. Psoriasis is characterized by hyperproliferation of keratinocytes which trigger skin immune. Autophagy-based unconventional secretion（autosecretion）is the biological process which mediate extracellular secretion of the unconventional secretory proteins by autophagic vacuole. Our preliminary study found that the autophagy marker protein LC3A was over expressed in psoriatic KCs and it was involved in the regulation of autophagy-based unconventional secretion pathway. We also investigated the regulation role of LC3A in psoriatic KCs. Our preliminary results suggest that the unacidified autophagy vacuolar may be a potential cause of autophagic secretion in KCs. Based on psoriatic KCs model and clinical tissue samples, we planned to further explore the intracellular signaling and molecular mechanisms in psoriatic KCs. On this basis, we also further investigate the effects of autophagy-based unconventional secretion on the immuno-microenvironment of psoriasis in the conditional knockout mice. Finally, we will reveal the mechanism of autophagic secretion on the molecular interaction network in the microenvironment of psoriatic lesion via genomic and proteomic analysis. Our research will provide a novel ideas for the research of the pathogenesis of psoriasis and the clinical treatment.

银屑病是一种常见的、严重危害患者身心健康的自身免疫性疾病。角质形成细胞（KCs）在银屑病免疫微环境中发挥重要免疫调节作用，是银屑病的执行者和最终表现者。自噬性分泌是一种经新型的自噬泡介导非经典分泌蛋白胞外分泌的生物学过程，其分子机制尚不清楚。前期研究中，我们发现银屑病KCs中自噬标志物的亚型LC3A介导了该分泌途径，且其对KCs病变具有调控作用；另外我们的研究提示自噬溶酶体的酸化障碍可能是自噬性分泌的潜在诱因。我们拟利用银屑病体外模型以及临床组织样本，揭示银屑病KCs中自噬性分泌途径的分子机制。在此基础上，利用条件性敲除鼠，阐明自噬性分泌对银屑病免疫微环境的调控作用。进而结合基因组和蛋白组学分析，深刻解读自噬性分泌对银屑病皮损免疫微环境分子关联网络的调控机制。该项目的实施，能够揭示LC3A介导银屑病中自噬性分泌的分子机制，同时增进对银屑病发病机制的理解，为银屑病的治疗提供新的思路。

自噬性非经典分泌途径作为一种新型自噬途径，其作用分子机制尚不清楚，且在疾病中相关报道罕见。该项目通过深究自噬性非经典分泌途径在银屑病中可能具有的重要生理意义和机制，希望为银屑病病理机制研究和治疗提供新的理论依据和实验基础。该项目研究中，我们发现银屑病患者皮损表皮区自噬标志蛋白水平显著增加，进一步研究发现该自噬水平的活化受丝裂原活化蛋白激酶家族介导的信号通路调控。表皮自噬缺陷缓解了小鼠银屑病模型皮损表征，并降低了皮损区炎症反应。深入研究发现，角质形成细胞自噬能够直接介导自噬分泌蛋白，即警报素分子的非经典分泌，而非经常规的内质网-高尔基体分泌途径，揭示了该细胞中自噬性分泌途径。并且发现角质形成细胞来源，而非其他免疫相关细胞来源的自噬分泌蛋白对银屑病皮损炎症发挥重要调控作用。中和自噬分泌蛋白能够几乎消除自噬充足和自噬缺陷的角质形成细胞之间的银屑病相关炎症反应的差异，相反，重组自噬分泌蛋白能够几乎完全恢复由于表皮自噬缺陷导致的银屑病皮损增殖和炎症降低，体现了自噬性非经典分泌对银屑病皮损免疫微环境的重要调控作用。我们进一步对银屑病皮损中自噬分泌蛋白介导的下游信号进行探究，发现经表皮自噬介导分泌的警报素胞外分泌后，作用于角质形成细胞，促进趋化因子和抗菌肽表达，进而趋化和激活真皮γδT等银屑病重要免疫细胞，产生大量IL-17A等炎症因子，构成银屑病皮损中促炎细胞和分子网络，恶化银屑病进程。该项目揭示了银屑病中自噬性非经典分泌途径的作用和分子机制。通过本项目资助，我们目前1篇相关SCI研究论文已见刊，1篇相关SCI研究论文已在线发表。另外，参加了美国免疫学年会，相关研究成果被会议收录摘要1篇。