Porphyromonas Gingivalis Promotes Mitochondrial Dysfunction Through Drp1-dependent Mitochondrial Fission In Endothelial Cells

Objective: Porphyromonas gingivalis(P.gingivalis),a key pathogen in periodontitis,has been shown as an independent risk factor to atherosclerosis(AS).And emerging evidence proved an association between mitochondrial dysfunctions and AS.However,the definite mechanisms that P.gingivalis promotes atherosclerotic formation and whether mitochondrial dysfunctions plays a role in it remain elusive.In our study,a variety of approaches have been pursued to investigate the impact of P.gingivalis on mitochondrial dysfunction and the potential mechanism involved and to explore the possible pathway of AS caused by P.gingivalis.Methods: EA.hy926 cells were infected with P.gingivalis ATCC 33277 at a multiplicity of infection(MOI)of 100 for 2 h,6 h,12 h,24 h for a subsequent series of assays.The mitochondrial morphology of EA.hy926 cells infected with P.gingivalis was determined through a transmission electron microscope.Mito-Tracker Red CMXRos staining and laser scanning confocal were used to quantitative analysis of the mitochondrial network.Laser scanning confocal and flow cytometry analysis were performed to detected mitochondrial reactive oxygen species(mt ROS)and mitochondrial membrane potential(MMP).The expression and distribution of key fusion and fission proteins was evaluated by western blot and immunofluorescence.Mdivi-1,a specific Drp1 inhibitor,was used to pretreated the cells to check the role of phosphorylation of Drp1 in mitochondrial dysfunction.Results: 1.P.gingivalis infection leads to increased fragmentation and division of mitochondria.2.P.gingivalis infection resulted in mt ROS increased and MMP collapse.3.P.gingivalis infection upregulated phosphorylation of Drp1(Ser616)and translocation of Drp1 to mitochondria were illustrated.4.Mdivi-1 pretreatment significantly inhibited mitochondrial fragmentation and dysfunction induced by P.gingivalis.Conclusion: 1.P.gingivalis infection promotes mitochondrial fragmentation and dysfunction in endothelial cells.2.p-Drp1(ser616)mediated P.gingivalis-induced mitochondrial fragmentation and dysfunction.