Objective To investigate the effect of mitochondrial unfolded protein response(UPRmt)on lipid metabolism in human kidney 2(HK-2)cells.Methods Lipid accumulation was induced by palmitic acid(PA)in HK-2 cells.The cells were pretreated with siRNA or CDDO respectively.The intracellular lipid accumulation was observed by oil red staining;mitochondrial membrane potential(MMP)was measured by JC-1.The contents of reactive oxygen species(ROS)in mitochondria were measured by Mito-SOX,and the expressions of HSP60,LONP1,CLPP,ACOX1,PPARα,PGC1α and CPT1α were detected by Western blotting.Results PA induced lipid aggregation,MMP decrease,ROS generation in mitochondria and the decreased expression of UPRmt proteins(e.g.,HSP60 and LONP1)in HK-2 cells.Pretreatment of HK-2 cells with siRNA could aggravate lipid aggregation,MMP decrease and ROS generation induced by PA,and further decrease the expression of HSP 60and LONP1.Pretreatment of HK-2 cells with CDDO alleviated lipid aggregation,MMP decrease,ROS generation and decreased HSP60 and LONP1 expressions induced by PA.Conclusion Lipid aggregation in HK-2 cells induced by PA may be related to mitochondrial dysfunction and UPRmt has a protective effect on HK-2 cells in the process.
mitochondrial unfolded protein reaction(UPRmt)palmitic acid(PA)human kidney 2(HK-2)celllipid accumulationreactive oxygen species(ROS)