光动力诱导的自噬调控皮脂腺功能及其在痤疮治疗中的机制研究

Acne is a very common chronic inflammatory disease involving hair follicle-sebaceous gland unit, which is still unclear on its etiology. Hyperfunction of sebaceous gland is the initial and crucial step, which also provides important targets for treatment and investigating new therapies. Photodynamic therapy (PDT) is a safe and effective strategy for acne, especially for moderate and severe acne, while its mechanism is still unclear. PDT could produce reactive oxygen species, which would induce apoptosis and necrosis of cells. Autophagy is an evolutionarily conserved process by which cells are able to degrade and recycle their own structural components. It is critical for the removal of damaged proteins and subcellular organelles, the maintenance of cell metabolism during starvation, cellular renovation during development and differentiation as well as for anti-bacterial and anti-viral defence. However, autophagy could be a form of cell death when it increases limitlessly. According to our early data, ALA-PDT could suppress proliferation and secreting of SZ95. Meanwhile, we found that PDT would induce autophagy. So, we raise the hypothesis: PDT modulates functions of sebaceous gland by inducing autophagy, resulting to improve acne. In this study, we plan to investigate the role of PDT-induced autophagy in sebaceous glands in vitro and in vivo with a trangenic-mouse strain which is deficient in autophagy specifically in sebaceous glands by crossing mice carrying a floxed ATG7 gene (ATG7 f/f) with mice Cre recombinase under the control of K14 promoter. This led to an efficient suppression of autophagy in sebocytes of K14 Cre ATG7 f/f mice. We intend to study the role of PDT-induced autophagy in modulating functions of sebaceous glands. Meanwhile, we plan to explore the condition of autophagy in serums and lesional tissues of acne patients before and after PDT. We expect our study would shed light on mechanism of PDT, optimizing clinical program, and providing new ideas and theoretical basis for R & D of new therapies.

痤疮是毛囊皮脂腺的慢性炎性疾病，确切机制尚不明了。皮脂腺功能亢进被视为发病的始动、关键的环节，是治疗的重要靶点。光动力疗法(PDT)是治疗痤疮，尤其是中重度痤疮的安全有效的方法。PDT可产⽣活性氧簇，诱导细胞的凋亡和坏死。自噬是广泛存在于真核细胞的降解途径，保护细胞免受氧化应激损伤，而当⾃噬⽔平持续上调，则成为细胞死亡的一种途径。我们在前期工作中发现，ALA-PDT能抑制人皮脂腺细胞(SZ95)的增殖和分泌，并能诱导其自噬。因此我们提出假设：PDT通过诱导皮脂腺细胞自噬调节皮脂腺功能。本课题通过建立皮脂腺细胞缺乏自噬功能的靶向性基因敲除小鼠模型、自噬基因沉默/过表达的SZ95细胞模型，探索PDT诱导的自噬在调节皮脂腺功能中所起的作用；并以痤疮患者为对象，研究自噬标志物在PDT前后组织和血清中的水平。为提高中重度痤疮的疗效及开发皮脂腺相关疾病的新疗法提供理论依据。

ALA-PDT促进NLRP3炎症小体形成，进而引起SZ95细胞IL-1β、IL-18释放和焦亡。ALA-PDT减弱皮脂腺细胞脂质合成和存活，为解释ALA-PDT治疗寻常痤疮，使皮脂腺萎缩、皮脂分泌降低奠定了理论基础。. ALA-PDT可以引起成纤维细胞死亡。ALA-PDT可以诱导成纤维细胞发生自噬，其可被自噬阻断剂3-MA阻断。. 痤疮患者外周血IGF-1与面部皮脂中单不饱和脂肪酸（C16:1n10）呈显著正相关。IGF-1可诱导皮脂腺细胞中IL-1α、IL-1β、IL-6、IL-8、TNF-α的上调，该过程受到芳香烃受体AhR的调控。与IGF-1显著相关的SA可加剧C.acne诱导的炎症反应，而多不饱和脂肪酸ALA可以抑制C.acne诱导的炎症反应。AhR可调控IGF-1诱导的TLR2/AKT途径。单不饱和脂肪酸C16:1n10有促炎促进痤疮的作用，而多不饱和脂肪酸Omega3 C18:3（ALA）则可能是痤疮的保护因素，为痤疮的治疗提供新的可能。. 在HaCat和原代角质形成细胞上，利用痤疮丙酸杆菌外泌体、超声灭火的痤疮丙酸杆菌、福尔马林灭火的痤疮丙酸杆菌干预，探索痤疮细胞模型。