Targeting keratinocyte cholesterol metabolism to reveal novel mechanisms for treating inflammatory skin disease

项目摘要 炎症涉及大量的急性和慢性皮肤病理，它们共同促成了皮肤的炎症。 患者和医疗保健负担高。外用皮质类固醇等外用免疫抑制剂是一线药物 尽管它们与无数的副作用如皮肤萎缩、纹和红斑痤疮有关， 还有其他的此外，虽然许多炎症性皮肤病涉及类似的免疫激活途径， 和疾病的进展，有针对性的抗炎治疗的发展将有助于划定我们的 了解伴随皮肤炎症的共同和独特的分子机制。 胆固醇是皮肤正常功能的组成部分，最近，过量的细胞内胆固醇已经被发现。 与培养的角质形成细胞中白细胞介素-17A（IL-17 A）的炎症激活相关。有趣的是，这些 发现类似于在活化的巨噬细胞中发现的胆固醇依赖性炎症过程， 这表明角质形成细胞可能受到类似的胆固醇调节机制， 炎症因此，需要研究来描述胆固醇代谢与 角化细胞诱导的炎症。我们的实验室率先合成了高密度脂蛋白样纳米颗粒（HDL 能够通过特异性结合清道夫受体B类1型来调节细胞胆固醇 （SR-B1），一种负责细胞胆固醇通量的转运蛋白。HDL NPs在皮肤中的应用具有吸引力 由于SR-B1在表皮中的良好存在和HDL的有利物理性质 可以使角质形成细胞靶向和定位于表皮的所有层的NP。此外，局部HDL 在受伤的角膜上皮细胞中给予NP已经证明了抗炎益处，进一步证实了其在角膜上皮细胞中的作用。 支持胆固醇调节和免疫激活之间的联系。我们的目标是使用HDL NPs作为强大的 这是一种机械研究胆固醇代谢变化如何影响皮肤炎症的工具。我们 总体假设如下：角质形成细胞胆固醇水平控制皮肤中的炎症信号。 在本研究的第一个目标中，我们将了解HDL NP如何在以下情况下调节角质形成细胞胆固醇： IL-17 A活化。在第二个目标中，我们将研究IL-17 A依赖性炎症信号在 角质形成细胞，特别关注测量已知的 使皮肤炎症永久化。在本研究的最终目的中，我们将研究靶向治疗的潜力。 使用咪喹莫特诱导的银屑病样小鼠模型作为皮肤模型的体内胆固醇调节 炎症项目成功将更好地阐明胆固醇代谢在炎症中的作用 皮肤病开发新的局部治疗，以减少炎症。

PROJECT SUMMARY Inflammation is involved in an abundant number of acute and chronic skin pathologies, which together contribute to high patient and healthcare burden. Topical immunosuppressants such as topical corticosteroids are first-line treatments despite their association with a myriad of adverse effects such as skin atrophy, striae, and rosacea, among others. Further, while many inflammatory skin conditions involve similar pathways of immune activation and disease progression, the development of targeted anti-inflammatory therapies would aid in delineating our understanding of the shared and unique molecular mechanisms that accompany inflammation in the skin. Cholesterol is integral to the normal functioning of skin and recently, excess intracellular cholesterol has been associated with inflammatory activation by interleukin-17A (IL-17A) in cultured keratinocytes. Interestingly, these findings resemble the cholesterol-dependent inflammatory processes found in activated macrophages, suggesting keratinocytes could be subjected to similar mechanisms of cholesterol regulation in the setting of inflammation. Therefore, research is required to delineate the relationship between cholesterol metabolism and keratinocyte-induced inflammation. Our lab pioneered a synthetic high-density lipoprotein-like nanoparticle (HDL NP) capable of modulating cellular cholesterol through specifically binding to scavenger receptor class B type 1 (SR-B1), a transporter responsible for cellular cholesterol flux. Application of HDL NPs in the skin is attractive due to the well-established presence of SR-B1 in the epidermis and the favorable physical properties of HDL NPs that may enable keratinocyte targeting and localization to all layers of the epidermis. Further, topical HDL NP administration in wounded corneal epithelial cells has demonstrated anti-inflammatory benefit, further supporting a link between cholesterol modulation and immune activation. We aim to use HDL NPs as a powerful tool to mechanistically study how changes in cholesterol metabolism affect inflammation in the skin. Our overarching hypothesis is the following: keratinocyte cholesterol levels control inflammatory signaling in the skin. In the first aim of the study, we will understand how HDL NP modulates keratinocyte cholesterol in the setting of IL-17A activation. In the second aim, we will investigate IL-17A-dependent inflammatory signaling in keratinocytes with a particular focus in measuring the expression of chemoattractants that are known to perpetuate skin inflammation. In the final aim of the study, we will investigate the therapeutic potential of targeting cholesterol modulation in vivo using the imiquimod-induced psoriasis-like mouse model as a model of skin inflammation. Project success will better delineate the role of cholesterol metabolism in inflammatory skin disease to develop novel topical therapies to reduce inflammation.