STRESS INDUCED SKIN MAST CELL ACTIVATION & VASODILATION

描述(由申请人提供)：我们对为什么慢性荨麻疹和牛皮癣等皮肤病会因压力而加重的理解存在根本差距。这项研究的长期目标是确定肥大细胞在炎症性疾病中的作用。这项应用的目的是通过小鼠模型和人类皮肤活检，确定促肾上腺皮质激素释放激素(CRH)受体和神经降压素(NT)受体-1在应激诱导的皮肤肥大细胞激活和血管通透性增加中的作用。束缚应激增加皮肤肥大细胞脱颗粒、CRH含量和血管通透性；这些影响在SP-/-和CRH-/-小鼠中不受影响，但在W7WV肥大细胞缺陷小鼠中不受影响。CRH在小鼠皮内注射时可增加血管通透性，但这一作用可被NTR-1拮抗剂SR48692阻断，在NT-/-小鼠中不存在，证明了NT的关键作用。应激可诱导背根神经节(DRG)皮肤终末释放CRH和NT，激活表达功能性CRHR和NTR-1的肥大细胞。慢性荨麻疹患者受累皮肤中CRHR-1和组氨酸脱羧酶(HOC)的表达增加，表明CRH和肥大细胞参与了这些发现的临床相关性。中心假设是，CRH在急性应激时在皮肤中释放，单独或与NT一起激活肥大细胞，导致血管通透性增加和神经源性炎症。在强大的初步数据指导下，将通过追求四个具体目标来检验这一假设：(1)使用CRHR-1-/-、CRHR-2-/-、双CRHR-/-或NTR-1-/-小鼠确定CRHR和NTR-1在应激和皮内CRH诱导的皮肤肥大细胞激活和血管通透性方面的重要性。(2)用相应的CRHR-/-或NTR-1-/-小鼠的骨髓祖细胞重组W/WV肥大细胞缺陷小鼠，以确定皮肤肥大细胞是否需要表达CRHR或NTR-1。(3)采用状态-特质焦虑量表(STAI)研究CRHR和NTR-1在特应性皮炎、慢性荨麻疹和银屑病患者皮肤组织中的表达，并与血清CRH水平和应激程度进行相关分析。(4)研究CRH和NT对人皮肤活检组织和培养的人肥大细胞释放促炎细胞因子的影响。我们的方法是创新的，因为它利用基因敲除小鼠和重建技术来了解应激衍生神经肽如何促进皮肤炎症，并使用新的方法来检测介质释放。这项拟议的研究意义重大，因为它有望促进人们对急性应激如何增加皮肤血管通透性和神经源性炎症的理解。这是皮肤病理生理学中一个重要且未被研究的领域，对于了解皮肤病的发病机制和筛选可能发展为新的有效治疗方法的化合物具有潜在的适用性。

DESCRIPTION (provided by applicant): There is a fundamental gap in our understanding of why skin diseases, such as chronic urticaria and psoriasis, are aggravated by stress. The long-term goal of this research is to define the role of mast cells in inflammatory diseases. The objective of this application is to identify the contribution of the corticotropin-releasing hormone (CRH) receptors and neurotensin (NT) receptor-1 in stress-induced skin mast cell activation and increased vascular permeability, using both a mouse model and human skin biopsies. Restraint stress increases skin mast cell degranulation, CRH content and vascular permeability; these effects are unaffected in SP-/- and CRH-/- mice, but absent in W7WV mast cell deficient mice. CRH increases vascular permeability when injected intradermally in mice, but this effect is blocked by the NTR-1 antagonist SR48692 and is absent in NT -/- mice, demonstrating the critical role of NT. Stress may elicit release of CRH and NT from dorsal root ganglia (DRG) skin terminals and activate mast cells expressing functional CRHR and NTR-1. The clinical relevance of these findings is evidenced by increased expression of CRHR-1 and histidine decarboxylase (HOC) in affected skin from patients with chronic urticaria, indicating the involvement of CRH and mast cells. The central hypothesis is that CRH released in the skin by acute stress, alone or together with NT, activates mast cells leading to increased vascular permeability and neurogenic inflammation. Guided by strong preliminary data, this hypothesis will be tested by pursuing four specific aims: (1) Determine the importance of CRHR and NTR-1 on stress and intradermal CRH-induced skin mast cell activation and vascular permeability using CRHR-1-/-, CRHR-2-/-, double CRHR -/-, or NTR-1-/- mice. (2) Determine if CRHR or NTR-1 need to be expressed on skin mast cells by reconstituting W/WV mast cell deficient mice with bone marrow progenitors from the appropriate CRHR-/- or NTR-1 -/- mice. (3) Investigate the expression of CRHR and NTR-1 in human skin biopsies from atopic dermatitis, chronic urticaria and psoriasis patients, and correlate findings with serum CRH levels and extent of stress by using the State-Trait Anxiety Inventory (STAI). (4) Investigate the effect of CRH and NT on release from human skin biopsy explants and human cultured mast cells of proinflammatory cytokines. Our approach is innovative because it utilizes knockout mice and reconstitution techniques to understand how stress-derived neuropeptides contribute to skin inflammation, and employs novel methods of assaying mediator release. The proposed research is significant because it is expected to advance understanding of how acute stress increases skin vascular permeability and neurogenic inflammation. This is an important and under investigated area of skin pathophysiology that has potential applicability to understanding the pathogenesis of skin diseases and screening compounds that may develop into novel and effective treatments.