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Background: Beta-defensins (BDs) are antimicrobial peptides secreted upon epithelial injury. Both chemotactic and antimicrobial properties of BDs function as initial steps in host defense and prime the adaptive immune system in the body. Psoriasis, a chronic immune-mediated inflammatory disease, has both visible cutaneous manifestations as well as known associations with higher incidence of cardiometabolic complications and vascular inflammation. Objectives: We aimed to investigate the circulating expression of beta-defensin-2 (BD2) in psoriasis at baseline compared to control subjects, along with changes in BD2 levels following biologic treatment at one-year. The contribution of BD2 to subclinical atherosclerosis is also assessed. In addition, we have sought to unravel signaling mechanisms linking inflammation with BD2 expression. Methods: Multimodality imaging as well inflammatory biomarker assays were performed in biologic naïve psoriasis (n=71) and non-psoriasis (n=53) subjects. A subset of psoriasis patients were followed for one-year after biological intervention (anti-Tumor Necrosis Factor-α (TNFα), n=30; anti-Interleukin17A (IL17A), n=21). Measurements of circulating BD2 were completed by Enzyme-Linked Immunosorbent Assay (ELISA). Using HaCaT transformed keratinocytes, expression of BD2 upon cytokine treatment was assessed by quantitative polymerase chain reaction (qPCR) and ELISA. Results: Herein, we confirm that human circulating BD2 levels associate with psoriasis, which attenuate upon biologic interventions (anti-TNFα, anti-IL-17A). A link between circulating BD2 and sub-clinical atherosclerosis markers was not observed. Furthermore, we demonstrate that IL-17A-driven BD2 expression occurs in a Phosphatidylinositol 3-kinase (PI3-kinase) and Rac1 GTPase-dependent manner. Conclusions: Our findings expand on the potential role of BD2 as a tractable biomarker in psoriasis patients and describes the role of an IL-17A-PI3-kinase/Rac signaling axis in regulating BD2 levels in keratinocytes.
RESUMEN
PURPOSE OF REVIEW: Atherogenesis, once thought to be a passive process, is now recognized as a dynamic, immune-driven process. The critical innate immune cells, including neutrophils, normal-density granulocytes, and their newly identified subset low-density granulocytes, are moving to the forefront of interest in cardiovascular medicine due to their abundance in atherosclerotic plaques and chronic inflammatory diseases associating with early cardiovascular disease (CVD) such as psoriasis. In this review, we discuss the emerging roles of neutrophils in CVD and how they play a potential role in early CVD observed in psoriasis patients. This review aims to describe the roles of neutrophils in both early atherosclerosis and psoriasis. RECENT FINDINGS: Recent work has demonstrated mechanistic links between vascular inflammation and neutrophil frequency. Evolving mouse models and clinical trials targeting IL-17-associated pathways continue to elucidate contributions of neutrophils in both atherosclerosis and psoriasis. Early animal, in vitro and human studies suggest an important emerging role of neutrophils in atherosclerosis and psoriasis.