Autophagy is a housekeeping process that maintains cellular homeostasis through recycling of nutrients and degradation of damaged or aged cytoplasmic constituents. Over the past several years, accumulating evidence has suggested that autophagy can function as an intracellular innate defense pathway in response to infection with a variety of bacteria and viruses. Autophagy plays a role as a specialized immunologic effector and regulates innate immunity to exert antimicrobial defense mechanisms. Numerous bacterial pathogens have developed the ability to invade host cells or to subvert host autophagy to establish a persistent infection. In this review, we have summarized the recent advances in our understanding of the interaction between antibacterial autophagy (xenophagy) and different bacterial pathogens.
Animals ; Autophagy/*physiology ; Bacterial Infections/*immunology/metabolism ; Humans ; Immunity, Innate/physiology ; Reactive Oxygen Species/metabolism

Infection and inflammation account for approximately 25% of cancer-causing factors. Inflammation-related cancers are characterized by mutagenic DNA lesions, such as 8-oxo-7,8-dihydro-2'-deoxyguanosine (8-oxodG) and 8-nitroguanine. Our previous studies demonstrated the formation of 8-oxodG and 8-nitroguanine in the tissues of cancer and precancerous lesions due to infection (e.g., Opisthorchis viverrini-related cholangiocarcinoma, Schistosoma haematobium-associated bladder cancer, Helicobacter pylori-infected gastric cancer, human papillomavirus-related cervical cancer, Epstein-Barr virus-infected nasopharyngeal carcinoma) and pro-inflammatory factors (e.g., asbestos, nanomaterials, and inflammatory diseases such as Barrett's esophagus and oral leukoplakia). Interestingly, several of our studies suggested that inflammation-associated DNA damage in cancer stem-like cells leads to cancer development with aggressive clinical features. Reactive oxygen/nitrogen species from inflammation damage not only DNA but also other biomacromolecules, such as proteins and lipids, resulting in their dysfunction. We identified oxidatively damaged proteins in cancer tissues by 2D Oxyblot followed by MALDI-TOF/TOF. As an example, oxidatively damaged transferrin released iron ion, which may mediate Fenton reactions and generate additional reactive oxygen species. Dysfunction of anti-oxidative proteins due to this damage might increase oxidative stress. Such damage in biomacromolecules may form a vicious cycle of oxidative stress, leading to cancer development. Epigenetic alterations such as DNA methylation and microRNA dysregulation play vital roles in carcinogenesis, especially in inflammation-related cancers. We examined epigenetic alterations, DNA methylation and microRNA dysregulation, in Epstein-Barr virus-related nasopharyngeal carcinoma in the endemic area of Southern China and found several differentially methylated tumor suppressor gene candidates by using a next-generation sequencer. Among these candidates, we revealed higher methylation rates of RAS-like estrogen-regulated growth inhibitor (RERG) in biopsy specimens of nasopharyngeal carcinoma more conveniently by using restriction enzyme-based real-time PCR. This result may help to improve cancer screening strategies. We profiled microRNAs of nasopharyngeal carcinoma tissues using microarrays. Quantitative RT-PCR analysis confirmed the concordant downregulation of miR-497 in cancer tissues and plasma, suggesting that plasma miR-497 could be used as a diagnostic biomarker for nasopharyngeal carcinoma. Chronic inflammation promotes genetic and epigenetic aberrations, with various pathogeneses. These changes may be useful biomarkers in liquid biopsy for early detection and prevention of cancer.
Animals ; DNA Damage ; Epigenesis, Genetic ; Humans ; Inflammation ; etiology ; immunology ; Mice ; Neoplasms ; etiology ; genetics ; immunology ; Reactive Nitrogen Species ; metabolism ; Reactive Oxygen Species ; metabolism

The human intestinal microbiota is a community of 10(13)-10(14) microorganisms that harbor in the intestine and normally participate in a symbiotic relationship with human. Technical and conceptual advances have enabled rapid progress in characterizing the taxonomic composition, metabolic capacity and immunomodulatory activity of the human intestinal microbiota. Their collective genome, defined as microbiome, is estimated to contain > or =150 times as many genes as 2.85 billion base pair human genome. The intestinal microbiota and its microbiome form a diverse and complex ecological community that profoundly impact intestinal homeostasis and disease states. It is becoming increasingly evident that the large and complex bacterial population of the large intestine plays an important role in colorectal carcinogenesis. Numerous studies show that gut immunity and inflammation have impact on the development of colorectal cancer. Additionally, bacteria have been linked to colorectal cancer by the production of toxic and genotoxic bacterial metabolite. In this review, we discuss the multifactorial role of intestinal microbiota in colorectal cancer and role for probiotics in the prevention of colorectal cancer.
Animals ; Bacteroides/metabolism ; Colorectal Neoplasms/immunology/*microbiology ; Fatty Acids, Nonesterified/metabolism ; Humans ; Hydrogen Sulfide/metabolism ; Intestinal Mucosa/immunology/microbiology ; Metagenome ; *Probiotics ; Reactive Oxygen Species/metabolism ; Toxins, Biological/metabolism

To investigate the reversal effect of reduced glutathione (GSH) on suppression of NK cells by reactive oxygen metabolites (ROM) in K562 cells, interleukin-2 (IL-2) or mononuclear cell (Mo) was added in cultured cell line of K562 cells and NK cells, the yield of ROM and K562 cell suppression rate were observed. Then the histamine dihydrochloride (DHT) or GSH was added in the mixed cultured cell lines, the ROM production and K562 cell suppression rate were observed. The results showed that the ROM yield increased from 33.17 +/- 5.08 U/L to 223.59 +/- 9.41 U/L by IL-2, and K562 cell suppression rate increased from 65.56% to 85.89% by IL-2 (P < 0.01). The ROM yields were 389.79 +/- 43.83 U/ml, 456.74 +/- 42.77 U/ml and 601.42 +/- 21.92 U/ml respectively, and K562 cell suppression rates were 82.36%, 81.36% and 48.09% respectively, when Mo was added in the mixed cultured cell lines under ratios of E/Mo being 10/2, 10/5 and 10/10. When E/Mo was 10/2, DHT or GSH was added in the mixed cultured cell line ROM yield decreased from 389.79 +/- 3.83 U/L to 50.21 +/- 2.4 U/L or -3.58 +/- 9.49 U/L (P < 0.05) respectively. With increase of concentration of DHT or GSH, the ROM yield in the mixed cultured cell line decreased (P < 0.05), the K562 cell suppression rate increased from 82.53% to 94.64% or 96.39% (P < 0.05), the more ROM yield, the less K562 suppression rate (P < 0.05). When E/Mo is 10/5 or 10/10, the ROM yield decreased by the high concentration of DHT or GSH (P < 0.05), but the K562 cell suppression rate not increased by every concentration of DHT or GSH. GSH was as effective as DHT in the reversing ROM and increasing K562 cell suppression rate. It is concluded that GSH may reverse ROM and increase K562 cell suppression rate, and GSH is as effective as DHT, but GSH has less side-effect than DHT. Therefore, GSH would be better antileukemia immune adjuvant.
Adjuvants, Immunologic ; pharmacology ; Antineoplastic Agents ; pharmacology ; Cell Proliferation ; Coculture Techniques ; Glutathione ; pharmacology ; Histamine ; pharmacology ; Humans ; K562 Cells ; Killer Cells, Natural ; cytology ; immunology ; Reactive Oxygen Species ; metabolism

OBJECTIVEThe current study aims to investigate the effect of Hemagglutinating virus of Japan envelope (HVJ-E) on induction of apoptosis and autophagy in human prostate cancer PC3 cells, and the underlying mechanisms.

METHODSPC3 cells were treated with HVJ-E at various multiplicity of infection (MOI), and the generated reactive oxygen species (ROS), cell viability, apoptosis, and autophagy were detected, respectively. Next, the role of ROS played in the regulation of HVJ-E-induced apoptosis and autuphagy in PC3 cells were analysed. In the end, the relationship between HVJ-E-induced apoptosis and autuophagy was investigated by using rapamycin and chloroquine.

RESULTSFlow cytometry assay revealed that HVJ-E treatment induced dose-dependent apoptosis and that the JNK and p38 MAPK signaling pathways were involved in HVJ-E-induced apoptosis in PC3 cells. In addition, HVJ-E was able to induce autophagy in PC3 cells via the class III PI3K/beclin-1 pathway. The data also implyed that HVJ-E-triggered autophagy and apoptosis were ROS dependent. When ROS was blocked with N-acetylcysteine (NAC), HVJ-E-induced LC3-II conversion and apoptosis were reversed. Interestingly, HVJ-E-induced apoptosis was significantly increased by an inducer of autophagy, rapamycin pretreatment, both in vitro and in vivo.

CONCLUSIONHVJ-E exerts anticancer effects via autophagic cell death in prostate cancer cells.

Apoptosis ; physiology ; Autophagy ; physiology ; Cell Line, Tumor ; Cell Survival ; Humans ; Male ; Oncolytic Virotherapy ; Prostatic Neoplasms ; metabolism ; Reactive Oxygen Species ; metabolism ; Sendai virus ; immunology ; physiology ; Virus Inactivation

Conglutinin is a high molecular-weight lectin originally detected in bovine serum. It belongs to the family of collectins that bind sugar residues in a Ca(2+)-dependent manner and are effector molecules in innate immunity. Conglutinin appears to play an important role in immune defense mechanisms, showing antiviral and antibacterial activities when tested in vivo and in vitro. The present study evaluated the effect of conglutinin on the respiratory bursts in bovine peripheral phagocytes. Using nitroblue tetrazolium and hydrogen peroxide assays, we showed that sugar ligand-bound conglutinin stimulated the production of superoxide and H2O2 in granulocytes whereas the non-sugar-bound form of conglutinin inhibited these processes. These results indicate that both forms of conglutinin are able to interact with surface leukocyte receptors but have opposite effects on phagocytic activity. Our findings suggest that conglutinin bound to sugar residues on microbial surfaces can induce oxygen burst in phagocytes, and thereby mediates the elimination of pathogens and prevents the spread of infection.
Animals ; Cattle/*immunology ; Collectins/*pharmacology ; Enzyme-Linked Immunosorbent Assay/veterinary ; Female ; Granulocytes/*drug effects/immunology ; Hydrogen Peroxide/immunology ; Immunity, Innate/drug effects/immunology ; Phagocytosis/immunology ; Reactive Oxygen Species/*immunology ; Respiratory Burst/*drug effects/immunology ; Serum Globulins/*pharmacology ; Statistics, Nonparametric ; Superoxides/immunology

Reactive oxygen species (ROS) production is one of the main mechanisms used to kill microbes during innate immune response. D-lactic acid, which is augmented during acute ruminal acidosis, reduces platelet activating factor (PAF)-induced ROS production and L-selectin shedding in bovine neutrophils in vitro. This study was conducted to investigate whether acute ruminal acidosis induced by acute oligofructose overload in heifers interferes with ROS production and L-selectin shedding in blood neutrophils. Blood neutrophils and plasma were obtained by jugular venipuncture, while ruminal samples were collected using rumenocentesis. Lactic acid from plasma and ruminal samples was measured by HPLC. PAF-induced ROS production and L-selectin shedding were measured in vitro in bovine neutrophils by a luminol chemiluminescence assay and flow cytometry, respectively. A significant increase in ruminal and plasma lactic acid was recorded in these animals. Specifically, a decrease in PAF-induced ROS production was observed 8 h after oligofructose overload, and this was sustained until 48 h post oligofructose overload. A reduction in PAF-induced L-selectin shedding was observed at 16 h and 32 h post oligofructose overload. Overall, the results indicated that neutrophil PAF responses were altered in heifers with ruminal acidosis, suggesting a potential dysfunction of the innate immune response.
Acidosis/chemically induced/immunology/*veterinary ; Animals ; Blood ; Cattle ; Cattle Diseases/chemically induced/*immunology ; Female ; Flow Cytometry/veterinary ; *Immunity, Innate ; L-Selectin/metabolism ; Neutrophils/*drug effects ; Oligosaccharides/*pharmacology/toxicity ; Platelet Activating Factor/*pharmacology ; Reactive Oxygen Species/metabolism ; Rumen

Tyrosine kinases are one of the most important regulators for intracellular signal transduction related to inflammatory responses. However, there are no reports describing the effects of tyrosine kinases on neutrophil apoptosis induced by Entamoeba histolytica. In this study, isolated human neutrophils from peripheral blood were incubated with live trophozoites in the presence or absence of tyrosine kinase inhibitors. Entamoeba-induced receptor shedding of CD16 and PS externalization in neutrophils were inhibited by pre-incubation of neutrophils with the broad-spectrum tyrosine kinase inhibitor genistein or the Src family kinase inhibitor PP2. Entamoeba-induced ROS production was also inhibited by genistein or PP2. Moreover, genistein and PP2 blocked the phosphorylation of ERK and p38 MAPK in neutrophils induced by E. histolytica. These results suggest that Src tyrosine kinases may participate in the signaling event for ROS-dependent activation of MAPKs during neutrophil apoptosis induced by E. histolytica.
*Apoptosis ; Cells, Cultured ; Entamoeba histolytica/*immunology/*pathogenicity ; GPI-Linked Proteins/metabolism ; Genistein/metabolism ; Humans ; Neutrophils/*immunology ; Protein Kinase Inhibitors/metabolism ; Pyrimidines/metabolism ; Reactive Oxygen Species/metabolism ; Receptors, IgG/metabolism ; src-Family Kinases/antagonists & inhibitors/*metabolism

Reactive oxygen species (ROS) play an important role in the pathogenesis of airway inflammation and hyperresponsiveness. Recent studies have demonstrated that antioxidants are able to reduce airway inflammation and hyperreactivity in animal models of allergic airway disease. A newly developed antioxidant, small molecular weight thiol compound, N-acetylcysteine amide (AD4) has been shown to increase cellular levels of glutathione and to attenuate oxidative stress related disorders such as Alzheimer's disease, Parkinson's disease, and multiple sclerosis. However, the effects of AD4 on allergic airway disease such as asthma are unknown. We used ovalbumin (OVA)-inhaled mice to evaluate the role of AD4 in allergic airway disease. In this study with OVA-inhaled mice, the increased ROS generation, the increased levels of Th2 cytokines and VEGF, the increased vascular permeability, the increased mucus production, and the increased airway resistance in the lungs were significantly reduced by the administration of AD4. We also found that the administration of AD4 decreased the increases of the NF-kappaB and hypoxia-inducible factor-1alpha (HIF-1alpha) levels in nuclear protein extracts of lung tissues after OVA inhalation. These results suggest that AD4 attenuates airway inflammation and hyperresponsiveness by regulating activation of NF-kappaB and HIF-1alpha as well as reducing ROS generation in allergic airway disease.
Acetylcysteine/*analogs & derivatives/therapeutic use ; Animals ; Asthma/drug therapy/*immunology/pathology ; Bronchial Hyperreactivity/*drug therapy/metabolism ; Hypoxia-Inducible Factor 1, alpha Subunit/*metabolism ; Mice ; NF-kappa B/*metabolism ; Ovalbumin/immunology ; Reactive Oxygen Species/*metabolism ; Vascular Endothelial Growth Factor A/metabolism

To investigate the effect of a new reactive oxygen metabolites (ROM) scavenger as immune adjuvant in NK cell-mediated killing effect on K562 cell, IL-2 and PHA were used to activate monocyte to produce ROM, and different concentrations of tiopronin as ROM scavenger was used in the cultivated systems with different ratio of monocytes plus NK cells and K562 cells, while histamine dihydrochloride (DHT) with different concentrations was used as positive control. The reuslts indicated that after IL-2 and PHA were supplemented in the cultivated systems mixing with NK cells and K562 cells as the E/T ratio was 10/1, the ROM production increased from 33.17 +/- 25.02 U/ml to 223.59 +/- 59.41 U/ml (P < 0.05) while K562 cell inhibition rate (KIR) increased from 65.56% to 85.89% (P < 0.05). When the monocytes as the E/MO ratios of 10/2, 10/5 and 10/10 were supplemented respectively, ROM production increased correspondingly (ROM production was 389.79 +/- 43.83 U/ml, 456.74 +/- 42.77 U/ml, 601.42 +/- 21.92 U/ml, respectively), and KIR was on the other round (KIR was 82.36%, 81.36%, 48.09% respectively). Tiopronin, DHT were used in the K562 + NK + MO + IL-2/PHA cultivated systems as the E/MO ratio was 10/2, the ROM production also decreased from 389.79 +/- 43.83 U/ml to -1.20 +/- 60.70 U/ml, 50.21 +/- 22.4 U/ml (P < 0.05), respectively, however KIR increased from 82.53% to 96.09% and 94.64% either (P < 0.05). Higher concentrations of tiopronin and DHT were used, ROM production decreased accordingly. There showed a reverse correlation between ROM production and KIR (r = -0.518). When E/MO ratio was 10/5 or 10/10, tiopronin at any testing concentration and DHT at the higher testing concentration could reduce the ROM production (P < 0.05), but did not improve KIR significantly (P > 0.05). Tiopronin was as good as DHT in ameliorating KIR (P > 0.05) and better than DHT in scavenging ROM (P < 0.05). It is concluded that (1) Monocytes are the major resources of ROM, and the ROM derived from monocytes can disable NK cells in killing neoplasm cells (K562 cells); (2) A new ROM scavenger, tiopronin, can scavenge ROM effectively, and reverse the ROM induced inhibition of NK cell-mediated killing of K562 cell in a certain extent. And tiopronin is better than DHT in scavenging ROM, and as good as DHT in up-regulating KIR. The new ROM scavenger tiopronin with less side effect may take the place of DHT as adjuvant during the adoptive immuno-therapy in leukemia.
Coculture Techniques ; Cytotoxicity Tests, Immunologic ; Cytotoxicity, Immunologic ; drug effects ; immunology ; Free Radical Scavengers ; pharmacology ; Humans ; K562 Cells ; Killer Cells, Natural ; cytology ; drug effects ; immunology ; Reactive Oxygen Species ; antagonists & inhibitors ; metabolism ; Tiopronin ; pharmacology