Linking Nicotinic Activation with Skin Innate Immunity and Atopic Dermatitis

描述（由申请人提供）：我们对抗菌肽（amp）的负调控如何导致与皮肤病相关的临床症状的理解存在一个重要的缺口。在这方面的研究知识的持续缺乏意味着一个重要的挑战，以开发改进的治疗皮肤感染和疾病。长期目标是确定乙酰胆碱烟碱受体（nAChR）激活如何抑制AMP的表达和活性，并将AMP调节的这些变化与AMP失调相关的人类皮肤病的因果治疗联系起来。本研究的目的是确定角化细胞中参与AMP抑制的nAChR亚型，评估nAChR激活改变的AMP谱，并将该机制与特应性皮炎（AD）的发病机制联系起来。我们的假设是，角化细胞中过量的nAChR激活会损害皮肤amp的正常加工和功能，从而导致AD的发病。我们的假设是基于初步数据，即nAChR激活显著降低AMP活性和对皮肤感染的抵抗力。AD患者的皮肤屏障受损，包括AMP表达减少，这被认为会导致炎症和感染。应激可能通过增加表皮乙酰胆碱和nAChR的激活从而破坏正常的AMP调节和微生物敏感性，从而加剧AD的临床表现。我们进行这些研究的基本原理是，大多数研究都集中在amp的正调控上，以增加其表达和活性，但识别那些抑制或减少的分子

DESCRIPTION (provided by applicant): An important breach exists in our understanding of how the negative regulation of antimicrobial peptides (AMPs) leads to the clinical symptoms associated with skin disease. The persistent lack of knowledge in this area of research signifies an important challenge to develop improved therapies for cutaneous infection and disease. The long-term goal is to identify how acetylcholine nicotinic receptor (nAChR) activation suppresses AMP expression and activity, and relate these changes in AMP regulation to the causal treatment of human skin diseases associated with AMP dysregulation. The objective of the proposed research is to identify the nAChR subtype(s) involved in AMP suppression in keratinocytes, evaluate the AMP profile altered by nAChR activation, and link this mechanism to the pathogenesis of Atopic Dermatitis (AD). Our hypothesis is that excess nAChR activation in keratinocytes impairs the normal processing and function of cutaneous AMPs, which contributes to the pathogenesis of AD. Our hypothesis was formulated based on preliminary data establishing that nAChR activation significantly reduced AMP activity and the resistance to cutaneous infection. Patients with AD develop a compromised skin barrier, which includes decreased AMP expression thought to precipitate inflammation and infection. Stress likely exacerbates the clinical manifestations of AD by increasing epidermal ACh and, consequently, nAChR activation to compromise normal AMP regulation and microbial susceptibility. Our rationale for these studies is that most research has focused on the positive regulation of AMPs to increase their expression and activity, yet identifying those molecules that inhibit or diminish AMP activity is critical to develop better clinical remedies to ameliorate the symptoms associated with AD and other inflammatory skin diseases. Driven by compelling preliminary data, our hypothesis will be evaluated by addressing three Specific Aims: 1) Identify which nAChR subtypes are involved in AMP suppression and identify the AMP profile in primary normal human epidermal keratinocytes (NHEKs) in vitro; 2) Determine the role of nAChR activation in the AMP response to infection in vivo; 3) Link mechanisms of nAChR signaling to the pathogenesis of AD. For Aim 1, NHEKs will be stimulated with nAChR agonists and antagonists to assess known AMPs and identify new antimicrobial molecules using established biochemical techniques. Aim 2 will use mice with altered states of nAChR activation to analyze the AMP response to infection using established proteomic approaches. Aim 3 will demonstrate that nAChR activation participates in the suppression of the AMP response to infection in skin from AD patients using molecular approaches. Our approach is innovative because it utilizes novel proteomic and molecular techniques to further define how nAChR activation influences the epidermal AMP response to infection. The proposed studies are significant because they are anticipated to identify the major nAChR signaling mechanism that negatively regulates AMP activity in skin, and identify alternative pathways for disease progression.