[Pathogenic role of NDUFA13 inactivation in spontaneous hepatitis in mice and the mechanism].

OBJECTIVE:To investigate the role of NDUFA13 inactivation in the pathogenesis of spontaneous hepatitis in mice and explore the possible mechanisms. METHODS:Hepatocyte-specific NDUFA13 knockout (NDUFA13fl/-) mice were generated by intercrossing NDUFA13fl/fl and Alb-Cre mice based on Cre/loxP transgenic technology, and tail and liver DNA of the mice was genotyped by PCR analysis. Ten NDUFA13fl/- mice and 10 littermate control NDUFA13fl/fl mice were housed, and in each group, 5 mice were euthanized at the age of 4 weeks and the other 5 at two years for pathological examination of the liver tissues with HE staining. Immunohistochemistry was used to verify the expression levels of NDUFA13, NF-κB/p65, NF-κB/p-p65 and inflammasome NLRP3. The total intracellular ROS and mitochondrial ROS levels were measured with a ROS staining kit. The expressions of the inflammatory cell markers (CD45, MPO, and F4/80) and inflammatory cytokines (IL1β and IL33) in the liver were detected with immunohistochemistry and immunofluorescence assay. RESULTS:Liver-specific NDUFA13 heterozygous knockout mice were successfully constructed as verified by PCR results. HE staining revealed severe liver damage in both 4- week-old and 2-year-old NDUFA13fl/- mice as compared with their littermate controls. Immunohistochemistry showed a significant decrease of NDUFA13 expression in both 4-week-old and 2-year-old NDUFA13fl/- mice (P < 0.05). The expression levels of NF-κB signals p65, p-p65 and NLRP3 inflammasomes were all significantly increased in NDUFA13fl/- mice (P < 0.05). The total intracellular ROS and mitochondrial ROS levels in NDUFA13fl/- mice were also significantly increased. NDUFA13 knockout obviously promoted the expression of the inflammatory cell markers (CD45, MPO and F4/80) and the secretion of IL-1β and IL-33 in the liver tissue of the mice (P < 0.05). CONCLUSIONS:Hepatocytes-specific NDUFA13 ablation can trigger spontaneous hepatitis in mice possibly mediated by the activation of ROS/NF-κB/NLRP3 signaling.