瘦素受体在小鼠皮肤中表达及瘦素受体阳性细胞在皮肤发育和创伤愈合中的作用

Expression of leptin receptor in mouse skin and the role of leptin receptor-positive cells in skin development and wound healing

背景:最近研究发现瘦素受体可以标记小鼠成体骨髓间充质干细胞,并参与小鼠骨折后骨的再生和修复,但是皮肤中是否存在瘦素受体阳性间质细胞,以及瘦素受体阳性细胞在皮肤发育和损伤修复中是否有重要作用并不清楚。目的:探究瘦素受体在小鼠皮肤中的表达以及瘦素受体阳性细胞在皮肤发育和创伤愈合中的作用。方法:该实验经上海交通大学实验动物伦理与使用委员会批准,批准号为1504002。利用经典的Cre-loxP系统构建LepR-Cre;tdTomato小鼠,示踪瘦素受体在小鼠皮肤中的表达。借助流式细胞仪对Tomato阳性瘦素受体谱系细胞进行细胞表面标记物分析。在LepR-Cre;tdTomato小鼠背部构建全层皮肤切除创伤模型,追踪瘦素受体阳性细胞在皮肤创伤愈合过程中的分布。构建在瘦素受体谱系细胞中特异性敲除Tsc1的LepR-Cre;Tsc1fl/fl小鼠,探究Tsc1对小鼠皮肤发育的影响。结果与结论:①瘦素受体在小鼠皮肤的真皮乳头、间质和真皮白色脂肪层均有表达;②免疫荧光染色发现瘦素受体可以与间质细胞标记物Vimentin和脂肪细胞标记物Perilipin部分共标。细胞表面标记物分析发现瘦素受体谱系细胞为CD11b-CD45-CD31-,同时表达间充质干细胞标记物CD73、Sca-1,即瘦素受体标记皮肤中的一类间充质干细胞;③LepR-Cre;tdTomato小鼠皮肤打孔的研究发现瘦素受体阳性细胞参与皮肤创伤愈合的进程;④在瘦素受体谱系细胞中敲除Tsc1后,小鼠皮肤真皮层和真皮白色脂肪层厚度增加、脂肪细胞数量增多。总的来说,该研究证实了瘦素受体在小鼠皮肤中表达,且在皮肤中瘦素受体谱系细胞参与组织发育及损伤修复。

BACKGROUND:It is believed that leptin receptor(LepR)marks the adult bone marrow mesenchymal stem cells in mice and LepR^(+)cells contribute to the regeneration of fractured bone.However,the residence of LepR^(+)stromal cells in skin and the function of the population in skin development and repair are poorly understood.OBJECTIVE:To investigate the expression of LepR in mouse skin and the role of LepR^(+)cells in development and tissue repair.METHODS:The study was approved by the Experimental Animal Ethics and Use Committee of Shanghai Jiao Tong University with the approval No.1504002.The LepR-Cre;tdTomato mice were generated by using the classic Cre-loxP system for tracing the expression of LepR in mouse skin.Flow cytometry was used to analyze surface markers on Tomato+cells.A full-thickness skin excision wound model was constructed on the back of LepR-Cre;tdTomato mice to trace the distribution of LepR^(+)cells in skin wound healing.The LepR-Cre;Tsc1fl/fl mice for specific deletion of Tsc1 in LepR^(+)cells were constructed to identify the role of Tsc1 in mouse skin development.RESULTS AND CONCLUSION:(1)LepR was expressed in dermal papilla,stroma,and dermal white adipose tissue in mice skin.(2)Immunofluorescence staining revealed that LepR^(+)cells partially co-expressed with stromal marker Vimentin and adipocyte marker Perilipin.Cell surface marker analysis showed that LepR lineage cells were negative for CD11b,CD45,and CD31,and positive for CD73 and Sca-1.LepR labeled a population of mesenchymal stem cells in mouse skin.(3)Punching experiment of LepR-Cre;tdTomato mice uncovered that LepR^(+)cells were involved in injury repair.(4)The LepR-Cre;Tsc1fl/fl mice presented the phenotype that the thickness of dermis and dermal white adipose tissue increased and the number of adipocytes increased significantly.It is concluded that LepR is expressed in mouse skin and cells of the LepR lineage in the skin are involved in tissue development and damage repair.