interleukin-8 and 3-methyladenine

Retinal pigment epithelial (RPE) cells can undergo different forms of cell death, including autophagy-associated cell death during age-related macular degeneration (AMD). Failure of macrophages or dendritic cells (DCs) to engulf the different dying cells in the retina may result in the accumulation of debris and progression of AMD. ARPE-19 and primary human RPE cells undergo autophagy-associated cell death upon serum depletion and oxidative stress induced by hydrogen peroxide (H2O2). Autophagy was revealed by elevated light-chain-3 II (LC3-II) expression and electron microscopy, while autophagic flux was confirmed by blocking the autophago-lysosomal fusion using chloroquine (CQ) in these cells. The autophagy-associated dying RPE cells were engulfed by human macrophages, DCs and living RPE cells in an increasing and time-dependent manner. Inhibition of autophagy by 3-methyladenine (3-MA) decreased the engulfment of the autophagy-associated dying cells by macrophages, whereas sorting out the GFP-LC3-positive/autophagic cell population or treatment by the glucocorticoid triamcinolone (TC) enhanced it. Increased amounts of IL-6 and IL-8 were released when autophagy-associated dying RPEs were engulfed by macrophages. Our data suggest that cells undergoing autophagy-associated cell death engage in clearance mechanisms guided by professional and non-professional phagocytes, which is accompanied by inflammation as part of an in vitro modeling of AMD pathogenesis.

Topics: Adenine; Autophagy; Biomarkers; Cell Line; Chloroquine; Coculture Techniques; Culture Media, Serum-Free; Gene Expression; Genes, Reporter; Green Fluorescent Proteins; Humans; Hydrogen Peroxide; Interleukin-6; Interleukin-8; Macrophages; Macular Degeneration; Microtubule-Associated Proteins; Models, Biological; Oxidative Stress; Phagocytosis; Primary Cell Culture; Retinal Pigment Epithelium; Triamcinolone

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.

Topics: 1,2-Dihydroxybenzene-3,5-Disulfonic Acid Disodium Salt; Acetylcysteine; Adenine; Animals; Autophagy; Autophagy-Related Protein 12; Autophagy-Related Protein 5; Caco-2 Cells; Cell Line, Tumor; Epithelial Cells; Free Radical Scavengers; Fusobacterium Infections; Fusobacterium nucleatum; Gene Expression Regulation; Humans; Interleukin-1beta; Interleukin-8; Macrolides; Mice; Mice, Inbred C57BL; Reactive Oxygen Species; RNA, Small Interfering; Signal Transduction; Tumor Necrosis Factor-alpha

Seawater drowning can lead to acute lung injury (ALI). However, the molecular and cellular mechanisms underlying this phenomenon remain elusive. The overall aim of this study is to clarify the role of autophagy in seawater-induced ALI, by which we can further understand the molecular mechanism and develop new methods for prevention and treatment of seawater-induced ALI. In this study, electron microscopy, western blot analysis, and RT-PCR were used to detect autophagy in lung tissues. Moreover, arterial blood gas analysis, lung weight coefficient, TNF-α, IL-8 in bronchoalveolar fluid (BALF), histopathology were used to detect the lung injury of seawater exposure. An inhibitor of autophagy (3-Methyladenine, 3-MA) was injected intraperitoneally before seawater exposure to further explore the role of autophagy in ALI. Electron microscopy revealed increasing autophagosomes in alveolar epithelial cell in seawater group compared with the control. The transcription and expression levels (mRNA and protein levels) of the LC3 II significantly increased in lung tissue of seawater group compared with those in control group. Furthermore, the alterations of autophage were basically consistent with the changes in arterial blood gas, lung weight coefficient, TNF-α, IL-8 in BALF and morphologic findings. In addition, inhibition of autophagy by 3-MA partly ameliorated seawater-induced ALI, as indicated by reduced lung weight coefficient and TNF-α in BALF, as well as increased PaO2. In conclusion, seawater aspiration triggered autophagy, and autophagy may be a scathing factor responsible for ALI induced by seawater.

Topics: Acute Lung Injury; Adenine; Animals; Autophagy; Disease Models, Animal; Interleukin-8; Male; Microscopy, Electron, Transmission; Microtubule-Associated Proteins; Near Drowning; Rats; Rats, Sprague-Dawley; Respiratory Aspiration; RNA, Messenger; Seawater; Tumor Necrosis Factor-alpha