Identification And Function Studies Of Fabp4+ Cells In Mouse Lung

Fatty acid binding protein 4(FABP4)is one of the most studied subtypes in the fatty acid binding protein(FABP)family,which mainly participate in lipid metabolism and signal transduction in cells and regulate cell growth,differentiations,and inflammatory response.It is well known that lung is the largest organ exposed to the environment.Besides changing oxygen,the primary function of the lung,it plays indispensable role in host defense and immue response as well,which are vital to our life.In recent years,there have been some studies on Fabp4 in bronchial inflammation,but few on Fabp4 in lung development and homeostasis.Here,we generated Fabp4-Cre;Rosa26-tdTomato mice to explore the expression of Fabp4 in lungs.We also generated Fabp4-Cre;iDTR mice by injecting with diphtheria toxin to specifically remove the FABP4+ cells.This can determine the functions of Fabp4+ cells in lung.We found that macrophages,clara cells,type II alveolar cells,myofibroblasts and vimentin+ mesenchymal cells were labeled by Fabp4,while smooth muscle cells and bronchial ciliated cells were not labeled.When the Fabp4+ cells were removed by DT injection,the percentages of bronchial clara cells and ciliated cell were decreased.Our results suggest,Fabp4+ clara cells may have stem cell features and affect the proliferation and self-renewal of clara cells and ciliated cells in lung.This study revealed the expression pattern of Fabp4+ in the lung of mice and preliminarily explored the functions of Fabp4+ cells in lung development.This laid a foundation for the study of pulmonary immune response and homeostasis.Moreover,Fabp4 may become a potential target for the treatment of lung diseases.