Burkholderia pseudomallei rpoS mediates iNOS suppression in human hepatocyte (HC04) cells.
Burkholderia pseudomallei is an intracellular Gram-negative bacterial pathogen and the causative agent of melioidosis, a widespread disease in Southeast Asia. Reactive nitrogen, in an intermediate form of nitric oxide (NO), is one of the first lines of defense used by host cells to eliminate intracellular pathogens, through the stimulation of inducible nitric oxide synthase (iNOS). Studies in phagocytotic cells have shown that the iNOS response is muted in B. pseudomallei infection, and implicated the rpoS sigma factor as a key regulatory factor mediating suppression. The liver is a main visceral organ affected by B. pseudomallei, and there is little knowledge about the interaction of liver cells and B. pseudomallei This study investigated the induction of iNOS, as well as autophagic flux and light-chain 3 (LC3) localization in human liver (HC04) cells in response to infection with B. pseudomallei and its rpoS deficient mutant. Results showed that the rpoS mutant was unable to suppress iNOS induction and that the mutant showed less induction of autophagy and lower co-localization with LC3, and this was coupled with a lower intracellular growth rate. Combining these results suggest that B. pseudomallei rpoS is an important factor in establishing infection in liver cells.
Department of Biochemistry, Faculty of Science, Mahidol University, Bangkok 10400, Thailand.
Sucharat
S
Sanongkiet
Chulabhorn International College of Medicine, Thammasart University, Rangsit campus, Pathumthani 12120, Thailand.
Saranyoo
S
Ponnikorn
Center for Innovation Development and Technology Transfer, Faculty of Medical Technology, Mahidol University, Salaya, Nakhon Pathom 73170, Thailand.
Rachanee
R
Udomsangpetch
Department of Biochemistry, Faculty of Science, Mahidol University, Bangkok 10400, Thailand pexcotung@gmail.com.
Sumalee
S
Tungpradabkul
D001343:Autophagy; D001426:Bacterial Proteins / Q000235:genetics / Q000378:metabolism*; D016957:Burkholderia pseudomallei / Q000235:genetics* / Q000254:growth & development / Q000378:metabolism; D002460:Cell Line; D004790:Enzyme Induction; D022781:Hepatocytes / Q000201:enzymology* / Q000382:microbiology*; D054884:Host-Pathogen Interactions; D006801:Humans; D008554:Melioidosis / Q000382:microbiology; D050296:Microbial Viability; D008869:Microtubule-Associated Proteins / Q000378:metabolism; D009154:Mutation; D052247:Nitric Oxide Synthase Type II / Q000096:biosynthesis* / Q000235:genetics; D012808:Sigma Factor / Q000235:genetics / Q000378:metabolism*
D001426:Bacterial Proteins; C477012:MAP1LC3A protein, human; D008869:Microtubule-Associated Proteins; D012808:Sigma Factor; C069567:sigma factor KatF protein, Bacteria; D052247:Nitric Oxide Synthase Type II
Burkholderia pseudomallei; RpoS; autophagy; hepatocyte; inducible nitric oxide synthase (iNOS); melioidosis