MOLECULAR MECHANISMS OF THE ITCH SENSATION IN THE SPINAL CORD

描述(由申请人提供)：慢性瘙痒或瘙痒是一种严重的临床问题，没有有效的药物可用。慢性瘙痒的分子和细胞机制尚未得到很好的了解和研究。最近在脊髓中发现了第一个瘙痒特异性基因--胃泌素释放肽受体(GRPR)，为研究神经系统瘙痒感觉的分子和细胞基础开辟了道路。这一修订补充的目的是鉴定胃泌素释放肽(GRP)及其受体GRPR分别在皮肤、脊髓和脑中表达的细胞的特性。我们还计划检查慢性疼痛状态下的GRP纤维。为此，将通过敲入的方法产生GRP-EGFP小鼠和GRPR-EGFP-creERT2小鼠。GRP+纤维在表皮的神经支配将通过免疫细胞化学进行分析，而GRPR-EGFP神经元是否投射到脑将通过逆行标记技术确定。GRPR+细胞的分子特性也将通过免疫细胞化学和原位杂交进行分析。建议的研究将为我们可视化GRP/GRPR相关的瘙痒神经元通路提供优秀的遗传学和分子工具。GRP+或GRPR+表达细胞的鉴定将大大加快慢性瘙痒的研究步伐。 公共卫生相关性：慢性瘙痒或瘙痒是一个严重的临床问题，没有有效的药物可用。为了了解瘙痒的神经机制，将通过GRP-EGFP和GRPR-EGFP-creERT2小鼠的产生来研究表达瘙痒受体GRPR及其配体GRP的神经通路。拟议中的研究将促进我们对中枢和外周神经系统对瘙痒感觉的重要理解。

DESCRIPTION (provided by applicant): Chronic itch or pruritus represents a significant clinical problem for which no effective drugs are available. Molecular and cellular mechanisms of chronic pruritus are not well understood and understudied. Recent identification of the first itch-specific gene, gastrin-releasing peptide receptor (GRPR), in the spinal cord opens the way for studying molecular and cellular basis of itch sensation in the nervous system. The goal of this revision supplement is to characterize the identity of gastrin-releasing peptide (GRP)- and its receptor GRPR- expressing cells in the skin, the spinal cord and the brain, respectively. We also plan to examine GRP fibers in chronic pain states. To this end, GRP-eGFP mice and GRPR-eGFP-creERT2 mice will be generated by a knock-in approach. The innervation of GRP+ fibers in the epidermis will be analyzed by immunocytochemistry, whereas whether GRPR-eGFP neurons project to the brain will be determined by retrograde labeling technique. The molecular identity of GRPR+ cells will also be analyzed by immunocytochemistry and in situ hybridization. The proposed studies should provide excellent genetic and molecular tools essential for us to visualize GRP/GRPR- related itch neuronal pathways. Characterization of GRP+ or GRPR+ expressing cells should greatly expedite the tempo of the research on chronic itch. PUBLIC HEALTH RELEVANCE: Chronic itch or pruritus represents a significant clinical problem for which no effective drugs are available. To understand the neural mechanisms of itch, the neuronal pathways that express the itch receptor, GRPR, and its ligand GRP, will be studied by the generation of GRP-eGFP and GRPR-eGFP-creERT2 mice. The proposed studies will advance our understanding of both central and peripheral neural systems important for itch sensation.