Identification And Functional Study Of Mitochondrial Uncoupling Protein In Mice Skin Tissue

Uncoupling is a reaction which occurs in the process of oxidative phosphorylation in mitochondria.It mainly can activate the substrate oxidation and consume the energy of oxidation to produce heat.Uncoupling in respiration,along with heat production during energy consumption,plays an important role in energy balance and body weight control.It also has positive significance for metabolic diseases such as obesity and can prevent the accumulation of oxygen free radicals(ROS)produced by mitochondria.Uncoupling proteins are a kind of carrier proteins located in mitochondrial inner membrane,which is responsible for uncoupling during oxidative phosphorylation.The most important role of uncoupling proteins is participating in the regulation of body temperature,maintaining the body's thermal balance by converting energy into heat.Uncoupling proteins are also involved in the Inhibition of the formation of undesirable ROS in vivo.Non-shivering thermogenesis is a heat-producing way obtained in the process of the mammalian evolution in response to cold environment.It is highly correlated with the uncoupling protein 1(UCPI)and can be induced by cold exposure and norepinephrine injection,resulting in increased expression of UCP1.UCP1 was previously thought to be specifically expressed in brown adipose tissue.Until recent years,it has been found that UCP1 is also expressed in human skin tissue.UCP1 is highly homologous to human and mice,but the existence and function of UCP1 in mice skin tissue is unclear.In this study,based on the study on wild-type and UCP1 knock-out mice,we used the mice brown adipose tissue as a positive control,and measured the expression level of UCP1 mRNA and protein.We found that UCP1 mRNA and protein exist in mice skin tissue.By separating the epidermis and the dermis,we further confirmed that the existence of UCP1 in the mice skin tissue is in the epidermal tissue,not in the dermal tissue.In order to further determine whether UCP1 is functional in epidermal tissue,we tried to induce the increase of UCP1 expression in the epidermal tissue by cold exposure.The result suggested that cold exposure can increase the expression level of UCP1 mRNA in the epidermal tissue,but there are differences in the response of UCP1 to the short-term cold exposure between epidermal tissue and brown adipose tissue.Then,we compared the effects of cold exposure and norepinephrine injection on the expression and function of UCP1 in the epidermal tissue and brown adipose tissue.In summary,the mitochondrial uncoupling protein UCP1 exists in the epidermis of mice skin tissue.While under cold exposure conditions,UCP1 expression level elevates and plays the uncoupling function.There are similarities and differences in the function of UCP1 between epidermal tissue and brown adipose tissue.This paper extends our understanding of the distribution and functions of mitochondrial uncoupling proteins.And it may have potential value in the treatment of energy metabolism-related diseases and the inhibition of ROS in cancer patients.However,the research on animal level and clinical application still need further exploration.