Chronic rhinosinusitis-associated olfactory loss

描述（由申请人提供）：嗅觉丧失是慢性鼻窦炎（CRS）的常见症状，显著降低了受影响患者的生活质量。传统上，嗅觉丧失被认为是由于炎症后嗅裂阻塞或嗅神经上皮损伤而发生的。虽然这在某些情况下是正确的，但可能还有其他细胞和分子机制调节CRS中的嗅觉功能。CRS的一个标志性特征是存在由浸润性白细胞产生的炎性细胞因子介质。在这些细胞因子中，肿瘤坏死因子α（TNF-1）是特别令人感兴趣的，因为其在CRS相关炎症中的中心作用及其在调节神经发生和模式化神经元细胞死亡中的公认功能。PI最近产生了一个小鼠模型，诱导TNF-1的表达，特别是在嗅上皮。在该模型中，TNF-1诱导导致气味敏感性丧失，并且在某些条件下导致嗅觉感觉神经元（OSN）死亡。在许多细胞类型中，CRS相关的TNF-1和其他细胞因子通过多种信号传导途径（包括MAP激酶和转录因子NF-：B的活化）直接改变钙稳态。我们假设CRS中存在的炎症介质通过直接作用于OSN和嗅觉祖细胞而引起嗅觉功能障碍。我们的诱导性嗅觉炎症小鼠模型为研究急性和慢性炎症对嗅觉上皮功能和结构的影响提供了一种新的工具。该提议的中心假设是由TNF-1诱导的炎症通过三种主要机制促进嗅觉丧失：1）OSN对气味剂的脱敏; 2）诱导OSN凋亡;和3）抑制嗅上皮再生。一个综合的方法，涉及生理和分子技术将被用来解剖慢性嗅觉炎症嗅觉损失的潜在机制。本提案中描述的实验将为介导炎症细胞因子对神经功能影响的信号通路提供新的见解，并可能导致治疗CRS相关嗅觉丧失的新治疗方法。

DESCRIPTION (provided by applicant): The loss of the sense of smell is a common symptom of chronic rhinosinusitis (CRS) that markedly diminishes the quality of life of affected patients. Traditionally, olfactory loss has been thought to occur by obstruction of the olfactory cleft or damage to the olfactory neuroepithelium subsequent to inflammation. While this is true in some cases, it is likely that there are other cellular and molecular mechanisms that modulate olfactory function in CRS. A hallmark feature of CRS is the presence of inflammatory cytokine mediators produced by infiltrating leukocytes. Among these cytokines, tumor necrosis factor alpha (TNF-1) is particularly interesting because of its central role in CRS- associated inflammation and its recognized functions in regulating neurogenesis and patterned neuronal cell death. The PI has recently generated a mouse model of inducible TNF-1 expression specifically within the olfactory epithelium. TNF-1 induction in this model causes loss of odorant sensitivity and, under certain conditions, death of olfactory sensory neurons (OSNs). In many cell types, TNF-1 and other cytokines relevant in CRS directly alter calcium homeostasis through multiple signaling pathways including activation of MAP kinases and the transcription factor NF-:B. It is our hypothesis that inflammatory mediators present in CRS cause olfactory dysfunction through their direct effects on OSNs and olfactory progenitor cells. Our induced olfactory inflammation mouse model provides a novel tool with which to study the effect of acute and chronic inflammation on the function and structure of the olfactory epithelium. The central hypothesis of this proposal is that inflammation induced by TNF-1 promotes the loss of olfaction through three principal mechanisms: 1) desensitization of OSNs to odorants; 2) induction of OSN apoptosis; and 3) inhibition of olfactory epithelial regeneration. An integrated approach involving physiological and molecular techniques will be utilized to dissect the underlying mechanisms of olfactory loss in chronic olfactory inflammation. The experiments described in this proposal will afford new insights into the signaling pathways that mediate inflammatory cytokine effects on neural function and potentially lead to new therapeutic approaches in treating CRS-associated olfactory loss.