Abstract

Brucellosis, acting as a typical chronic zoonotic disease, is caused by the invasion ofBrucellainto the human body. Outer membrane protein 25 (Omp25), specifically localized on theBrucellamembrane, is the main virulence factor ofBrucellaand participates in multiple links of the damage process. Omp25c, a porin protein ofBrucella, is a paralog of Omp25 with high sequence identity. NADH dehydrogenase [ubiquinone] complex I assembly factor 2 (Ndufaf2) has a key function in cell energy metabolism, particularly in the formation and activity of the mitochondrial respiratory chain. Loss of Ndufaf2 results in oxidative stress and mitochondrial DNA (mtDNA) deletion. However, the functional relationship between Omp25c and Ndufaf2, the underlying mechanism of the proteins, remains unclear. In this work, we purified the Omp25c and Ndufaf2proteins. Our data revealed that Omp25c directly interacts with Ndufaf2, as determined using Biacore analysis. In addition, assays revealed that Ompa2c reshapes the host cell’s redox environment by decreasing the oxidized nicotinamide adenine dinucleotide/reduced nicotinamide adenine dinucleotide (NAD+/NADH) ratioand adenosine triphosphate (ATP) production, whereas Ndufaf2 exerts an opposing regulatory effect; Co-expression results further revealed an antagonistic relationship between the two during metabolic processes. These findings provide a new perspective for elucidating the mechanisms of mitochondrial functional regulation inBrucella–host interactions and lay the theoretical and experimental foundation for drug development targeting metabolic interventions to eliminate intracellular pathogens.