The Dynll1-Cox4i1 Complex Regulates Intracellular Pathogen Clearance via Release of Mitochondrial Reactive Oxygen Species

Abstract

Cellular membrane proteins are a critical part of the host defense mechanisms against infection and intracellular survival of Listeria monocytogenes. The complex spatiotemporal regulation of bacterial infection by various membrane proteins has been challenging to study. Here, using mass spectrometry analyses, we depicted the dynamic expression landscape of membrane proteins upon L. monocytogenes infection in dendritic cells. We showed that Dynein light chain 1 (Dynll1) formed a persistent complex with the mitochondrial cytochrome oxidase Cox4i1, which is disturbed by pathogen insult. We discovered that the dissociation of the Dynll1-Cox4i1 complex is required for the release of mitochondrial reactive oxygen species and serves as a regulator of intracellular proliferation of Listeria monocytogenes. Our study shows that Dynll1 is an inhibitor of mitochondrial reactive oxygen species and can serve as a potential molecular drug target for antibacterial treatment.

Proteomics reveals the potential mechanism of Mrps35 controlling Listeria monocytogenes intracellular proliferation in macrophages

“…ΔLLO L. monocytogenes (DP‐L2161) is lacking the LLO gene, which cannot escape from the phagocytic vacuole to cytoplasm [20]. L. monocytogenes RFP (DP‐L5538) strain can express red fluorescent protein after lysosome‐escaped, because the RFP tag is expressed under the actA promoter [7]. First, the ΔactA L. monocytogenes load in Mrps35 KD Raw264.7 cells at 2, 4 and 6 h of infection were significantly higher than those in WT Raw264.7 cells (Figure 2C).…”

“…At present, the research on the mechanism of host defense against L. monocytogenes infection mainly focuses on reactive oxygen species [7], vesicle and membrane fusion [9], mitochondria [11], autophagy [6, 33], and various signal activation [2, 34‐36]. However, our research results provided new insights for evaluating the changes of proteins which related with the basic synthesis and metabolism of host cells during L. monocytogenes infection.…”

“…L. monocytogenes WT (10403S), Δhly (DP‐L2161, ΔLLO), ΔactA (DP‐L1942, ΔActin), and L. monocytogenes RFP (DP‐L5538) strains were saved in our laboratory [7, 9, 15]. We had already described the culture conditions of L. monocytogenes strains in previous reports [7, 15].…”

“…The current researches on the mechanism of macrophage defense against L. monocytogenes infection are mainly focused on vesicle transport [9], membrane fusion [10], reactive oxygen species [7], mitochondria [11], and the activation of various immune signals [2, 12‐14]. Few researchers pay attention to the changes in basic synthesis or metabolism‐related proteins of macrophage cells by L. monocytogenes infection.…”

“…For example, L. monocytogenes listeriolysin O (LLO) is a pore-forming enzyme that can destroy the phagosome [5]. Once L. monocytogenes escapes from the lysosomes of the macrophage cells, they can hijack the cytoskeleton protein of host to cross the cell membrane and spread to neighboring cells by secreting actin-assembly inducing protein (ActA) [7,8]. At present, it is not clear whether the macrophage cells possess additional strategies to limit the "second attack" of these successful L. monocytogenes.…”