Antagonizing roles of SHP1 in the pathogenesis of Helicobacter pylori infection.

BACKGROUND: SHP1 has been documented as a tumor suppressor and it was thought to play an antagonistic role in the pathogenesis of Helicobacter pylori infection. In this study, the exact mechanism of this antagonistic action was studied. MATERIALS AND METHODS: AGS, MGC803, and GES-1 cells were infected with H. pylori, intracellular distribution changes of SHP1 were first detected by immunofluorescence. SHP1 overexpression and knockdown were then constructed in these cells to investigate its antagonistic roles in H. pylori infection. Migration and invasion of infected cells were detected by transwell assay, secretion of IL-8 was examined via ELISA, the cells with hummingbird-like alteration were determined by microexamination, and activation of JAK2/STAT3, PI3K/Akt, and ERK pathways were detected by immunoblotting. Mice infection model was established and gastric pathological changes were evaluated. Finally, the SHP1 activator sorafenib was used to analyze the attenuating effect of SHP1 activation on H. pylori pathogenesis in vitro and in vivo. RESULTS: The sub-localization of SHP1 changed after H. pylori infection, specifically that the majority of the cytoplasmic SHP1 was transferred to the cell membrane. SHP1 inhibited H. pylori-induced activation of JAK2/STAT3 pathway, PI3K/Akt pathway, nuclear translocation of NF-κB, and then reduced EMT, migration, invasion, and IL-8 secretion. In addition, SHP1 inhibited the formation of CagA-SHP2 complex by dephosphorylating phosphorylated CagA, reduced ERK phosphorylation and the formation of CagA-dependent hummingbird-like cells. In the mice infection model, gastric pathological changes were observed and increased IL-8 secretion, indicators of cell proliferation and EMT progression were also detected. By activating SHP1 with sorafenib, a significant curative effect against H. pylori infection was obtained in vitro and in vivo. CONCLUSIONS: SHP1 plays an antagonistic role in H. pylori pathogenesis by inhibiting JAK2/STAT3 and PI3K/Akt pathways, NF-κB nuclear translocation, and CagA phosphorylation, thereby reducing cell EMT, migration, invasion, IL-8 secretion, and hummingbird-like changes.

Chronic exposure to polystyrene nanoplastics induces intestinal mechanical and immune barrier dysfunction in mice.

Micro(nano)plastics are prevalent in the environment, and prolonged exposure to them represents a threat to human health. The goal of this study is to assess the health risk of long-term exposure to nanoplastics (NPs) at environmental concentrations on the intestinal mechanical and immune barrier in mice. In this study, mice were provided drinking water containing polystyrene NPs (PS-NPs; 0.1, 1, and 10 mg·L-1) for 32 consecutive weeks. The levels of endocytosis proteins caveolin and clathrin and of tight junctional proteins claudin-1, occludin, and ZO-1, and morphological changes, proportion of lymphocytes B in MLNs and lymphocytes T in IELs and LPLs were determined by immunohistochemistry, hematoxylin-eosin, and flow cytometry assays in the intestinal tissues of mice at 28 weeks. The activities or concentrations of ROS, SOD, MDA, and GSH-Px and inflammatory factors (IL-1ß, IL-6, and TNF-α) in the intestinal tissues of mice were measured by ELISA at 12, 16, 20, 24, and 32 weeks. Compared with the control group, oral ingested PS-NPs entered the intestinal tissues of mice and upregulated expression levels of the clathrin and caveolin. The intestinal tissue structure of mice in the PS-NPs (1 and 10 mg·L-1) exposure groups showed significant abnormalities, such as villus erosion, decreased of crypts numbers and large infiltration of inflammatory cells. Exposure to 0.1 mg·L-1 PS-NPs decreased occludin protein levels, but not claudin-1 and ZO-1 levels. The levels of these three tight junction proteins decreased significantly in the 1 and 10 mg·L-1 PS-NPs exposed groups. Exposure to PS-NPs led to a significant time- and dose-dependent increase in ROS and MDA levels, and concurrently decreased GSH-Px and SOD contents. Exposure to PS-NPs increased the proportion of B cells in MLNs, and decreased the proportion of CD8+ T cells in IELs and LPLs. The levels of pro-inflammatory cytokines IL-6, TNF-α and IL-1ß were markedly elevated after PS-NPs exposure. Long-term PS-NPs exposure impaired intestinal mechanical and immune barrier, and indicate a potentially significant threat to human health.

Chloroquine inhibited Helicobacter pylori-related gastric carcinogenesis by YAP-ß-catenin-autophagy axis.

YAP participates in autophagy associated with many diseases. In this study, we demonstrate that YAP promotes autophagy by interacting with beclin 1, upregulating beclin 1 and LC3B-II protein expression, and promoting autophagosome formation after H. pylori infection in a vacuolating cytotoxin A-dependent manner. The protein levels of ß-catenin in the cytoplasm and nuclei of GES-1 cells and the mRNA levels of Axin2, Myc, Lgr5, and Ccnd1 were increased in H. pylori-infected cells or YAP-overexpressed cells, but were decreased in YAP-silenced cells. The ß-catenin inhibitor XAV939 significantly downregulated autophagy, whereas the activator LiCl showed opposite effects. An H. pylori-infected mouse model of gastric carcinoma was successfully established. The mouse model showed that H. pylori infection, when combined with NMU, promoted the tumorigenesis of gastric tissues; increased IL-1ß, IL-6, and TNF-α levels; promoted NO release; and increased the expression of beclin 1, LC3B-II more than NMU alone. Chloroquine inhibited these phenomena, but did not completely attenuate the effects of H. pylori. These results demonstrate that chloroquine can be used as a drug for the treatment of H. pylori-related gastric cancer, but the treatment should simultaneously remove H. pylori.

Helicobacter pylori infection induces autophagy via ILK regulation of NOXs-ROS-Nrf2/HO-1-ROS loop.

Reactive oxygen species (ROS) can regulate the occurrence of autophagy, and effective control of the balance between ROS and autophagy may be an important strategy for Helicobacter pylori induced gastric-related diseases. In this study, infection with H. pylori led to a lower level of ILK phosphorylation and increased ROS generation. Knockdown of ILK enhanced total ROS generation, and upregulated NADPH oxidase (NOX) subunit p22-phox levels. Inhibition of NOXs affected total ROS generation. The inhibition of NOX and ROS generation reduced Nrf2 and HO-1 levels, and knockdown of ILK significantly enhanced Nrf2 levels in H. pylori-infected GES-1 cells. Activation of Nrf2 by DMF decreased ROS levels. Therefore, NOX-dependent ROS production regulated by ILK was essential for activation of Nrf2/HO-1 signaling pathways in H. pylori-infected GES-1 cells. Beclin1, ATG5 and LC3B-II levels were higher both in H. pylori-infected and ILK-knockdown GES-1 cells. In NAC-pretreated GES-1 cells infected with H. pylori, the LC3B-II level was decreased compared to that in cells after H. pylori infection alone. Stable low expression of ILK with further knockdown of Beclin1 or ATG5 significantly reduced LC3B-II levels in GES-1 cells, while with the addition of the autophagy inhibitor chloroquine (CQ), LC3B-II and p62 protein levels were both remarkably upregulated. H. pylori accelerated the accumulation of ROS and further led to the induction of ROS-mediated autophagy by inhibiting ILK levels. Together, these results indicate that H. pylori infection manipulates the NOX-ROS-Nrf2/HO-1-ROS loop to control intracellular oxygen stress and further induced ROS-mediated autophagy by inhibiting ILK levels.

The phosphotransferase system gene ptsH affects persister formation in Klebsiella pneumoniae by regulating cyclic adenosine monophosphate levels.

Klebsiella pneumoniae is one of the most common opportunistic pathogens causing hospital- and community-acquired infections. Antibiotic resistance in K. pneumoniae has emerged as a major clinical and public health threat. Persisters are specific antibiotic-tolerant bacterial cells. Studies on the mechanism underlying their formation mechanism and growth status are scarce. Therefore, it is urgent to explore the key genes and signalling pathways involved in the formation and recovery process of K. pneumoniae persisters to enhance the understanding and develop relevant treatment strategies. In this study, we treated K. pneumoniae with a lethal concentration of levofloxacin. It resulted in a distinct plateau of surviving levofloxacin-tolerant persisters. Subsequently, we obtained bacterial samples at five different time points during the formation and recovery of K. pneumoniae persisters to perform transcriptome analysis. ptsH gene was observed to be upregulated during the formation of persisters, and down-regulated during the recovery of the persisters. Further, we used CRISPR-Cas9 to construct ΔptsH, the ptsH-knockout K. pneumoniae strain, and to investigate the effect of ptsH on the persister formation. We observed that ptsH can promote the formation of persisters, reduce accumulation of reactive oxygen species, and enhance antioxidant capacity by reducing cyclic adenosine monophosphate (cAMP) levels. To the best of our knowledge, this is the first study to report that ptsH plays a vital role in forming K. pneumoniae persisters. This study provided important insights to further explore the mechanism underlying the formation of K. pneumoniae persisters and provided a potential target for treating infection with K. pneumoniae persisters.

Analysis of cross neutralizing activity of antibodies from sera of severe fever with thrombocytopenia syndrome patients to deal with different genotype strains.

Background: Severe fever with thrombocytopenia syndrome bunyavirus (SFTSV) is a tick-borne virus that causes severe communicable fever with thrombocytopenia syndrome (SFTS) with an average case fatality rate of 10%. In the study, we aimed to identify the cross-neutralizing antibody (nAb) against different genotype strains from sera of SFTSV infected patients. Methods: Firstly the genotype of SFTSV was identified by constructing a phylogenetic tree based on the M segments epidemic in the Jiaodong area of Shandong province, then different sera of subjects cross reactive with recombinant Gn (rGn-Fc) or recombinant Gc (rGc-Fc) of 0921 strain were examined. The levels of polyclonal nAbs from sera of 25 convalescents were measured by a pseudovirus-based neutralizing experiment. Results: We found local endemic strains were mainly C2 and C3 isolates of SFTSV. 14 of 15 sera from donors reacted with 0921 rGn-Fc, and 9 of 15 sera from donors reacted with 0921 rGc-Fc. Cross nAbs were produced by 10 of 25 sera from donors during the period of 2019-2021. Among these, five nAbs (A2, A4, A5, L9, and L10) neutralized the pseudoviruses of HB29, Gangwon, HN13, HN20, SPL030A, and SD4 strains. Conclusion: Our data suggested that epidemic strains showed relatively stable heredity. Some blood sources from patients produced cross nAbs that could neutralize all of the strains examined. These findings highlight the important role played by humoral immunity in combatting SFTSV.

Oceanospirillum sediminis sp. nov., Isolated From Coastal Sediment in the Yellow Sea.

A novel Gram-negative, motile, aerobic, spiral-shaped bacterium designated D5T, was isolated from a coastal sediment collected in the Yellow Sea. Optimal growth occurred at 30 °C, pH 7.0-8.0 and in the presence of 1-3% (w/v) NaCl. Strain D5T contained ubiquinone 8 (Q-8) as the predominant respiratory quinone. The major fatty acids (> 10%) were C16:0, C16:1 ω7c/C16:1 ω6c and C18:1w7c/C18:1w6c. The main polar lipids were phosphatidylglycerol and phosphatidylethanolamine. The draft genome is 5.6 Mb in length, and DNA G + C content is 47.2 mol%. 16S rRNA gene sequences showed that strain D5T is most closely related to Oceanospirillum beijerinckii NBRC 15445T (97.8%, sequence similarity). However, the digital DNA-DNA hybridization (dDDH) value and average nucleotide identity (ANI) between strain D5T and O. beijerinckii is only 27.8% and 77.1%. Phylogenetic trees based on 16S rRNA gene sequences and whole genomes all indicated that strain D5T formed a separate branch in the genus Oceanospirillum. Combined results of the polyphasic analyses suggested that strain D5T represents a novel species in the genus Oceanospirillum, for which the name Oceanospirillum sediminis sp. nov. is proposed. The type strain is D5T (= MCCC 1K06061T = KCTC 62987T).

Polyethylene microplastics cooperate with Helicobacter pylori to promote gastric injury and inflammation in mice.

Microplastics provide stable habitats for the colonization and survival of pathogenic microorganisms, and cooperate with microorganisms to pose a potential threat to human health. In this study, polyethylene microplastics (PE-MPs) in artificial gastric juice time-dependently decomposed and broke into small-diameter PE-MP fragments that were more stable than those in an aqueous solution. Helicobacter pylori adhered to the surfaces of the PE-MPs to form a biofilm. The gastric tissues of mice treated with PE-MPs first and mixture of PE-MPs and H. pylori were positive for H. pylori infection in the 10th and 14th weeks after treatment, whereas those infected with H. pylori first and H. pylori alone were positive only in the 14th week after treatment. PE-MPs were visible in the gastric, intestinal, and liver tissues of mice treated with PE-MPs. The average diameter of the PE-MP fragments in the liver was greater than those of fragments that entered the gastric or intestinal tissues, and the average diameter of PE-MPs in the PE-MPs only-treated mice was significantly smaller than those of PE-MPs entering the intestinal tissues of the other groups. The infiltration of inflammatory cells was most serious in the mice treated with the mixture of PE-MPs and H. pylori, or with PE-MPs first and then H. pylori. Of all the groups, the gastric organ index and MPO, IL6, and TNF-α levels were highest in the mice treated with the mixture of PE-MPs and H. pylori. These results indicate that the interaction between PE-MPs and H. pylori contributed to the rapid bacterial colonization of gastric mucosal epithelial cells, improved the efficiency of PE-MP entry into tissues, and promoted gastric injury and inflammation in mice. These findings suggest that microplastics may provide a stable habitat for H. pylori, and act synergistically with H. pylori to pose a potential threat to human health.

Regulation of ß1-integrin in autophagy and apoptosis of gastric epithelial cells infected with Helicobacter pylori.

Helicobacter pylori infection is an essential factor in the development of human gastric diseases, but its pathogenic mechanism is still unclear. In this work we have showed that, the LC3II levels were increased and ß1-integrin levels were decreased in H. pylori-positive human gastric tissue samples and H. pylori co-cultured GES-1 cells. There was significant upregulation of LC3II levels and downregulation of P62 levels in GES-1 cells after ß1-integrin knockdown co-cultured with H. pylori. This indicated that ß1-integrin downregulation promoted autophagy in GES-1 cells after H. pylori infection. The cell apoptosis rate and poly ADP-ribose polymerase (PARP) and caspase-3 activities were increased in GES-1 cells pretreated with 3-methyladenine (3-MA ) after H. pylori infection. Furthermore, there was a significant decrease in apoptosis of ß1-integrin knockdown GES-1 cells co-cultured with H. pylori; apoptosis was also downregulated in ß1-integrin knockdown- and 3-MA-treated GES-1 cells co-cultured with H. pylori. Correspondingly, PARP and caspase-3 activities were decreased in ß1-integrin knockdown cells co-cultured with H. pylori and ß1-integrin knockdown-3-MA-treated-1 cells with H. pylori infection. Thus, ß1-integrin is a novel autophagy and apoptosis regulator during H. pylori infection. However, inhibition of autophagy did not reverse the decrease in apoptosis caused by downregulation of ß1-integrin.

Helicobacter pylori regulates ILK to influence autophagy through Rac1 and RhoA signaling pathways in gastric epithelial cells.

The ability of Helicobacter pylori to manipulate host autophagy is an important pathogenic mechanism. We found an inverse correlation between the expression of ILK and the autophagy marker protein LC3B in H. pylori-positive human samples, H. pylori-infected mice models and H. pylori-infected GES-1 cell lines. When the ILK-knockdown GES-1 cells were infected by H. pylori, CagA were significantly degraded, autophagosomes accumulation and autolysosomes formation were significantly increased, and LC3B protein levels and ratio of LC3BII to LC3BI were also remarkably upregulated. And chloroquine treatment increased LC3B levels in ILK-knockdown GES-1 cells. The expression levels of both Rac1 and RhoA were downregulated in GES-1 cells after H. pylori infection and were decreased in ILK-knockdown GES-1 cells. The mRNA and protein levels of PAK1, MLC, and LIMK were significantly decreased and cofilin mRNA and protein levels were significantly increased in GES-1 cells treated with the Rac1 inhibitor NSC 23766. The mRNA and protein levels of ROCK1, ROCK2, MLC, and LIMK1 were significantly reduced and cofilin mRNA and protein levels were significantly increased in GES-1 cells treated with the RhoA inhibitor CCG-1423. F-actin was significantly reduced in Rac1- or RhoA-inhibited GES-1 cells. F-actin depolymerization induced autophagosomes accumulation, autolysosomes formation, and the increase of LC3B levels in GES-1 cells. Therefore, these findings revealed that ILK could serve as a novel regulator to affect Rac1/PAK1 and RhoA/ROCKs signaling pathways, thereby influencing H. pylori-induced autophagy.

Tissue distribution of polystyrene nanoplastics in mice and their entry, transport, and cytotoxicity to GES-1 cells.

With the widespread use of plastics and nanotechnology products, nanoplastics (NPs) have become a potential threat to human health. It is of great practical significance to study and evaluate the distribution of NPs in mice as mammal models and their entry, transport, and cytotoxicity in human cell lines. In this study, we detected the tissue distribution of fluorescent polystyrene nanoplastics (PS-NPs) in mice and assessed their endocytosis, transport pathways, and cytotoxic effects in GES-1 cells. We found that PS-NPs were clearly visible in gastric, intestine, and liver tissues of mice and in GES-1 cells treated with PS-NPs. Entry of PS-NPs into GES-1 cells decreased with the inhibition of caveolae-mediated endocytosis (nystatin), clathrin-mediated endocytosis (chlorpromazine HCl), micropinocytosis (ethyl-isopropyl amiloride), RhoA (CCG-1423), and F-actin polymerization (lantrunculin A). Rac1 inhibitors (NSC 23766) had no significant effect on PS-NPs entering GES-1 cells. F-actin levels significantly decreased in CCG-1423-pretreated GES-1 cells exposed to PS-NPs. GES-1 cell ultrastructural features indicated that internalized PS-NPs can be encapsulated in vesicles, autophagosomes, lysosomes, and lysosomal residues. RhoA, F-actin, RAB7, and LAMP1 levels in PS-NPs-treated GES-1 cells were remarkably up-regulated and the Rab5 level was significantly down-regulated compared to levels in untreated cells. PS-NPs treatment decreased cell proliferation rates and increased cell apoptosis. The formation of autophagosomes and autolysosomes and levels of LC3II increased with the length of PS-NPs treatment. The results indicated that cells regulated endocytosis in response to PS-NPs through the RhoA/F-actin signaling pathway and internalized PS-NPs in the cytoplasm, autophagosomes, or lysosomes produced cytotoxicity. These results illustrate the potential threat of NPs pollution to human health.

Vibrio marinisediminis sp. nov., Isolated from Marine Sediment.

A novel Gram-stain-negative, facultative anaerobic, motile bacterium, designated as 404T, was isolated from a marine sediment sample in the Bohai Gulf, China. Growth was observed at 10-35 °C (optimum, 20-25 °C) and in the presence of 1.0-6.0% (w/v) NaCl (optimum, 1.0-3.0%). Phylogenetic analysis based on 16S rRNA gene sequences indicated that the strain 404T belonged to the genus Vibrio, showing the highest sequence similarity to Vibrio renipiscarius KCTC 42287T (97.6%). The draft genome is 4.5 Mb in length, containing 4278 protein-coding genes, 60 tRNA genes and 9 rRNA genes, and DNA G+C content is 44.1 mol%. Strain 404T contains phosphatidylglycerol, phosphatidylethanolamine, diphosphatidylglycerol, phosphatidylcholine, and phospholipid as the main polar lipids, and the predominant quinone is ubiquinone Q-8. The major cellular fatty acids (>8.0%) are C16 : 1ω6c and/or C16 : 1ω7c, C16 : 0, C18 : 1ω6c and/or C18 : 1ω7c. Strain 404T shows some typical characteristics among the members of genus Vibrio, while it can be clearly distinguished from the closely related type strains through genome analysis (average nucleotide identity and digital DNA-DNA hybridization values), fatty acid composition and a series of physiological and biochemical characteristics. On the basis of the polyphasic analysis, strain 404T is considered to represent a novel species of the genus Vibrio, for which the name Vibrio marinisediminis sp. nov., is proposed. The type strain is 404T (= MCCC 1H00367T = KCTC 62958T).

Construction and Investigation of MicroRNA-mRNA Regulatory Network of Gastric Cancer with Helicobacter pylori Infection.

BACKGROUND: Helicobacter pylori (H. pylori) is a common human pathogen, which is closely correlated with gastric cancer (GC). However, the mechanism of H. pylori-related GC has not been elucidated. This study aimed to explore the role of H. pylori infection in GC and find biomarkers for early diagnosis of H. pylori-related GC. METHODS: We identified differentially expressed microRNAs (DEMs) and genes (DEGs) from the Gene Expression Omnibus (GEO) dataset, constructed microRNA-(miRNA-)mRNA expression networks, analyzed the function and signal pathway of cross-genes, analyzed the relations between cross-genes and GC prognosis with the Cancer Genome Atlas (TCGA) data, and verified the expression of cross-genes in patients with H. pylori infection. RESULTS: 22 DEMs and 68 DEGs were identified in GSE197694 and GSE27411 dataset. 16 miRNAs and 509 genes were involved in the expression network, while the cross-genes of the network were mainly enriched in MAP kinase (MAPK) signaling pathway and TGF-beta signaling pathway. Patients with higher expression of hsa-miR-196b-3p, CALML4, or SMAD6 or lower expression of PITX2 or TGFB2 had better outcomes than those with lower expression of hsa-miR-196b-3p, CALML4, or SMAD6 or higher expression of PITX2 or TGFB2 (P < 0.05). Patients with H. pylori infection had a higher expression of hsa-miR-196b-3p and CALML4 than those without H. pylori infection (P < 0.05). CONCLUSION: The study of miRNA-mRNA expression network would provide molecular support for early diagnosis and treatment of H. pylori-related GC.

Halomonas marinisediminis sp. nov., A Moderately Halophilic Bacterium Isolated from the Bohai Gulf.

A novel Gram-stain-negative, moderately halophilic bacterium, designated strain 204T, was isolated from a marine sediment sample in the Bohai Gulf, Yellow Sea, China. Cells of strain 204T are aerobic, motile, cocci or short rods with two lateral flagella. Growth was observed at 15-40 °C (optimum, 30 °C), pH 6.0-9.0 (optimum, 7.0-7.5) and in the presence of 1.0-18.0% (w/v) NaCl (optimum, 3.0-8.0%). Phylogenetic analysis based on 16S rRNA gene sequences indicated that strain 204T belonged to the genus Halomonas, showing highest sequence similarity to Halomonas alimentaria YKJ-16T (98.08%), followed by Halomonas sediminicola (97.47%), Halomonas fontilapidosi (97.14%), Halomonas halodenitrificans (96.98%), Halomonas ventosae (96.92%), and Halomonas shengliensis (96.85%). The draft genome is 3.8 Mb in length, containing 3673 protein-coding genes, 62 tRNA genes and 10 rRNA genes, and DNA G+C content is 62.7 mol%. Strain 204T contains phosphatidylglycerol, phosphatidylethanolamine, and diphosphatidylglycerol as the main polar lipids, and the predominant respiratory quinone was ubiquinone Q-9. The major cellular fatty acids (> 5%) are C18:1ω7c, C16:1ω7c and/or C16:1ω6c, C16:0 and C12:03-OH. Strain 204T was clearly distinguished from the closely related type strains through phylogenetic analysis, dDNA-DNA hybridization, fatty acid composition data and a range of physiological and biochemical characteristics comparisons. On the basis of the polyphasic analysis, strain 204T is considered to represent a novel species of the genus Halomonas, for which the name Halomonas marinisediminis sp. nov. is proposed. The type strain is 204T (= MCCC 1H00366T = KCTC 62957T).

CD4 binding loop responsible for the neutralization of human monoclonal neutralizing antibody Y498.

Broad and potent human monoclonal neutralizing antibodies have considerable potential in the prevention and treatment of acquired immunodeficiency syndrome (AIDS). To identify the key amino acid recognition site contacted with neutralizing antibody Y498, peptides were panned from the PhD-12 peptide library and predicted using online software. Then, four key amino acid sites, G367, D368, E370, and V372 located on the CD4 binding loop on gp120 of envelope of human immunodeficiency virus-1 (HIV-1), were found to determine the neutralization of antibody Y498. Residue E370 is in the deep part of the CD4 binding loop, which affects Y498-mediated neutralization. This form of recognition leads to a somewhat limiting neutralization spectrum of neutralizing antibody Y498, although it has some neutralization ability. Further study of the interactions between the neutralizing antibody Y498 and its epitope on the surface of the virus may facilitate vaccine development and so prevent new AIDS cases.

Polyethylene microplastics affect the distribution of gut microbiota and inflammation development in mice.

Environmental pollution caused by plastics has become a public health problem. However, the effect of microplastics on gut microbiota, inflammation development and their underlying mechanisms are not well characterized. In the present study, we assessed the effect of exposure to different amounts of polyethylene microplastics (6, 60, and 600 µg/day for 5 consecutive weeks) in a C57BL/6 mice model. Treatment with a high concentration of microplastics increased the numbers of gut microbial species, bacterial abundance, and flora diversity. Feeding groups showed a significant increase in Staphylococcus abundance alongside a significant decrease in Parabacteroides abundance, as compared to the blank (untreated) group. In addition, serum levels of interleukin-1α in all feeding groups were significantly greater than that in the blank group. Of note, treatment with microplastics decreased the percentage of Th17 and Treg cells among CD4+ cells, while no significant difference was observed between the blank and treatment groups with respect to the Th17/Treg cell ratio. The intestine (colon and duodenum) of mice fed high-concentration microplastics showed obvious inflammation and higher TLR4, AP-1, and IRF5 expression. Thus, polyethylene microplastics can induce intestinal dysbacteriosis and inflammation, which provides a theoretical basis for the prevention and treatment of microplastics-related diseases.

Investigation on the role of gene hp0788 in Helicobacter pylori in infecting gastric epithelial cells.

Helicobacter pylori infection can cause a wide range of digestive diseases. Gene hp0788 encodes an outer membrane protein HofF, which can reduce the bacterial adherence to the GES-1 cells and affect pathogenesis of H. pylori. In this study, the role of hp0788 in H. pylori infection was further analyzed. RNA-seq data showed that two genes (hp0523 and hp0539), located on the cagPAI, were down-regulated in Δ0788 mutant. The changes were confirmed through qRT-PCR, and the expression of these two genes will be almost recovered to the normal level in complemented strain. These two genes, hp0523 and hp0539, are known to be necessary for integrated T4SS, which related to CagA translocation and IL-8 induction. In H. pylori infected assay, lower amount of phosphorylated CagA and lower induction of IL-8 were both detected in GES-1 cells infected by Δ0788 mutant, compared with the wild type strain. Meanwhile, these reductions almost recovered to the wild-type level in complemented strain. These results reveal that there is a correlation between hp0788 disruption and CagA/IL-8 decline. Deletion of CagA-encoding gene (hp0547) in Δ0788 mutant was further constructed. The double deleted mutant shows lower IL-8-inducing capability than Δ0788 mutant, indicated the correlation between deficiency of CagA and reduced IL-8 production. These results together imply that disruption of hp0788 might affect the efficiency of T4SS and CagA injection, then weaken the induction of IL-8 in infected GES-1 cells.

Detection of Neutralizing Antibodies in HIV-1 Patients on Antiretroviral Treatment for Over Ten Years.

BACKGROUND: Recently, many broadly applicable and potent neutralizing antibodies have been screened from HIV-1-infected patients. However, all these effective neutralizing antibodies were isolated from patients naive to anti-retroviral treatment (ART). METHODS: To better understand the induction of neutralizing antibodies in patients on ART, we screened 3 patients with an over ten-year infection history on ART from 350 patients in China for a cross-reactive neutralizing antibody response based on the use of different antigens and recombinant viruses. We studied the evolution of neutralizing activity in two patients during a one-year period with previously described recombinant viruses NL4-3 and SF162 using ELISA and neutralization assays. RESULTS: Antibodies purified from sera were able to react with recombinant virus antigens R2-gp120 and SF162-gp140 and neutralize SF162 recombinant virus but not NL4-3 recombinant virus. In addition, we observed a significant increase in the neutralizing response of immunoglobulin G (IgG) isolated from the serum sample in Patient 1 and compared it with the serum from Patient 1 six months ago. CONCLUSIONS: We thus confirm the possibility of production of neutralizing antibodies in patients infected for over ten years on ART, and it is possible over time of the improvement of HIV-1 potent neutralizing activity associated with viremia and immune reconstruction.

Aureibaculum marinum gen. nov., sp. nov., a Novel Bacterium of the Family Flavobacteriaceae Isolated from the Bohai Gulf.

A novel Gram-stain-negative bacterium, designated strain BH-SD17T, was isolated from a marine sediment sample in the Bohai Gulf, Yellow Sea, China. Cells of strain BH-SD17T are aerobic, yellow-colored, non-flagellated rods. Growth occurs between 15 and 40 °C (optimum, 30 °C), at pH 6.0-8.5 (optimum, 7.5) and with 1.0-8.0% (w/v) NaCl (optimum, 3.0%). Strain BH-SD17T contains phosphatidylethanolamine and two unidentified lipids as the major polar lipids. The predominant fatty acids are iso-C15:0 (28.5%), iso-C15:1 G (24.4%), and iso-C17:0 3-OH (12.3%). The major respiratory quinone is MK-6. Strain BH-SD17T shows moderate 16S rRNA gene sequence similarity to existing identified strains, is most closely related to the genera Lutimonas (92.1-92.4%), Lutibacter (91.6-92.3%), and Taeania (91.9%). Phylogenetic trees based on 16S rRNA gene sequences show that strain BH-SD17T forms a distinct lineage within the family Flavobacteriaceae. Based on the results of phenotypic, chemotaxonomic and phylogenetic analysis, strain BH-SD17T is considered to represent a novel genus and species in the family Flavobacteriaceae, for which the name Aureibaculum marinum is proposed. The type strain is BH-SD17T (=CCTCC AB 2017072T=KCTC 62204T).

The regulatory role of C1q on Helicobacter pylori-induced inflammatory cytokines secretion in THP-1 cells.

C1q, as a LAIR-1 ligand, maintains monocytes quiescence and possess immunosuppressive properties. To understand the roles and molecular mechanisms, C1q mediated inflammation cytokines and several pivotal proteins in THP-1 cells after H. pylori infection were detected. The results showed that the expression of IL-8, IL-10, LAIR-1, phosphorylated/total JNK, phosphorylated/total p38-MAPK, phosphorylated/total AKT and phosphorylated/total NF-κB were up-regulated significantly in THP-1 cells after H. pylori infection. There was significant upregulation in IL-10 concentration, phosphorylated/total p38-MAPK and phosphorylated/total AKT, and downregulation in phosphorylated/total JNK in non-H. pylori infected THP-1 cells pretreated with C1q. C1q was also able to increase IL-8 and IL-10 production, and reduce LAIR-1 and phosphorylated/total p38-MAPK expression in pretreatment-C1q THP-1 cells after H. pylori infection. These results together indicated that H. pylori might induce IL-8 and IL-10 production through JNK, p38-MAPK, PI3K/AKT and NF-κB signaling pathway. C1q manipulate LAIR-1 to regulation IL-8 and IL-10 secretion in THP-1 cells after H. pylori infection through the p38-MAPK signaling pathway. This information is helpful to further understand the role and mechanisms of C1q on inflammation cytokines secretion in monocytes after H. pylori infection.