Fusobacterium nucleatum-Induced Impairment of Autophagic Flux Enhances the Expression of Proinflammatory Cytokines via ROS in Caco-2 Cells

PLoS One. 2016 Nov 9;11(11):e0165701. doi: 10.1371/journal.pone.0165701. eCollection 2016.

Abstract

Fusobacterium nucleatum (F. nucleatum) plays a critical role in gastrointestinal inflammation. However, the exact mechanism by which F. nucleatum contributes to inflammation is unclear. In the present study, it was revealed that F. nucleatum could induce the production of proinflammatory cytokines (IL-8, IL-1β and TNF-α) and reactive oxygen species (ROS) in Caco-2 colorectal) adenocarcinoma cells. Furthermore, ROS scavengers (NAC or Tiron) could decrease the production of proinflammatory cytokines during F. nucleatum infection. In addition, we observed that autophagy is impaired in Caco-2 cells after F. nucleatum infection. The production of proinflammatory cytokines and ROS induced by F. nucleatum was enhanced with either autophagy pharmacologic inhibitors (3-methyladenine, bafilomycin A1) or RNA interference in essential autophagy genes (ATG5 or ATG12) in Caco-2 cells. Taken together, these results indicate that F. nucleatum-induced impairment of autophagic flux enhances the expression of proinflammatory cytokines via ROS in Caco-2 Cells.

MeSH terms

  • 1,2-Dihydroxybenzene-3,5-Disulfonic Acid Disodium Salt / pharmacology
  • Acetylcysteine / pharmacology
  • Adenine / analogs & derivatives
  • Adenine / pharmacology
  • Animals
  • Autophagy / drug effects
  • Autophagy-Related Protein 12 / antagonists & inhibitors
  • Autophagy-Related Protein 12 / genetics
  • Autophagy-Related Protein 12 / immunology
  • Autophagy-Related Protein 5 / antagonists & inhibitors
  • Autophagy-Related Protein 5 / genetics
  • Autophagy-Related Protein 5 / immunology
  • Caco-2 Cells
  • Cell Line, Tumor
  • Epithelial Cells / cytology
  • Epithelial Cells / drug effects
  • Epithelial Cells / immunology*
  • Free Radical Scavengers / pharmacology
  • Fusobacterium Infections / genetics
  • Fusobacterium Infections / immunology*
  • Fusobacterium Infections / microbiology
  • Fusobacterium Infections / pathology
  • Fusobacterium nucleatum / immunology*
  • Gene Expression Regulation
  • Humans
  • Interleukin-1beta / genetics
  • Interleukin-1beta / immunology*
  • Interleukin-8 / genetics
  • Interleukin-8 / immunology*
  • Macrolides / pharmacology
  • Mice
  • Mice, Inbred C57BL
  • RNA, Small Interfering / genetics
  • RNA, Small Interfering / metabolism
  • Reactive Oxygen Species / immunology*
  • Reactive Oxygen Species / metabolism
  • Signal Transduction
  • Tumor Necrosis Factor-alpha / genetics
  • Tumor Necrosis Factor-alpha / immunology*

Substances

  • ATG12 protein, human
  • ATG5 protein, human
  • Autophagy-Related Protein 12
  • Autophagy-Related Protein 5
  • Free Radical Scavengers
  • IL1B protein, human
  • Interleukin-1beta
  • Interleukin-8
  • Macrolides
  • RNA, Small Interfering
  • Reactive Oxygen Species
  • Tumor Necrosis Factor-alpha
  • 1,2-Dihydroxybenzene-3,5-Disulfonic Acid Disodium Salt
  • 3-methyladenine
  • bafilomycin A1
  • Adenine
  • Acetylcysteine

Grants and funding

This work was supported by a grant from National Natural Science Foundation of China (NSFC, 81301482 and 81501796), and the project of medical science and technology for training youth scholars of PLA (14QNP054).