Aeromonas sobria Induces Proinflammatory Cytokines Production in Mouse Macrophages via Activating NLRP3 Inflammasome Signaling Pathways

Apoptosis, MAPK signaling pathway affected in tilapia liver following nano-microplastics and sulfamethoxazole acute co-exposure

Studies showed that toxicants that adhered to the surface of nano-microplastics (NPs) have toxicological effects. Juvenile tilapia were divided into four groups namely the control group (A), 100 ng·L-1 sulfamethoxazole (SMZ) group (B), 75 nm NPs group (C) and SMZ + 75 nm NPs group (D), and were exposed to an acute test for 2, 4 and 8 days. The hepatic histopathological changes, enzymatic activities, transcriptomics and proteomics analysis have been performed. The results showed that; the enzymatic activities of anti-oxidative enzymes (ROS, SOD, EROD), energy (ATP), lipid metabolism (TC, TG, FAS, LPL, ACC), pro-inflammatory factors (TNFα, IL-1β) and apoptosis (Caspase 3) have decreased significantly at 8 d. Hepatic histopathological results revealed the narrowed hepatic sinuses, displaced nucleus, and vacuoles under SMZ exposure. Transcriptome results demonstrated that endocytosis, MAPK signaling pathway, apoptosis, lysosome and herpes simplex infection were enriched in group C at 8 d. apaf1, casp3a, nfkbiaa (apoptosis, except for 8 d) were significantly increased, il1b and tgfb3, fgfr2 showed significant increase and decrease in group C/D. ctsd and ctsk associated with apoptosis have been especially significantly increased at 8 d, while MAPK signaling pathway, gadd45ga, gadd45gb/gadd45gg have been significantly decreased and increased, as well as map3k3/map3k2 significantly decreased at 8 d. Apoptosis and MAPK signaling pathway were affected and the synergistic effect was verified in tilapia liver following NPs and SMZ acute co-exposure.

Gypenoside XLIX alleviates sepsis-associated encephalopathy by targeting PPAR-α

Sepsis-related systemic inflammation is a deadly condition with high rates of morbidity and mortality. There is evidence that sepsis affects the brain, and the most frequent organ dysfunction linked to sepsis is sepsis-associated encephalopathy. Sepsis-related brain damage can drastically reduce a patient's chances of survival. However, a specific treatment for sepsis-associated encephalopathy is not currently available. Consequently, to treat the brain damage caused by sepsis, investigating novel therapeutic strategies is imperative. After establishing the CLP-induced mouse SAE model, we treated the mice with Gyp-XLIX and evaluated apoptosis, neuroinflammation, brain damage, and oxidative stress in the brain tissue of each group of mice. Furthermore, the protective effects of Gyp-XLIX on LPS-treated BV-2 cells were assessed. We discovered that Gyp-XLIX treatment increased the survival rate of CLP-treated mice, alleviated SAE-related cerebral nerve abnormalities, and decreased blood-brain barrier breakdown, all of which could better preserve brain tissue in vivo. Furthermore, we identified associated proteins and found that Gyp-XLIX may reduce oxidative stress, cell apoptosis, and inflammation in the brain tissues of SAE mice. This observation was further validated in vitro. We established that Gyp-XLIX alleviates SAE by targeting PPAR-α. These findings may be important for the clinical applicability of Gyp-XLIX in SAE treatment. We found that Gyp-XLIX can alleviate brain injury in SAE by targeting PPAR-α and is a potential protective agent for SAE.

Integration analysis of miRNA-mRNA uncovers the molecular immune mechanism of macrophage response to Aeromonas veronii infection

Macrophages are innate immunity cells which play pivotal roles in infectious immunity. Aeromonas veronii is a zoonotic agent capable of causing sepsis and poses a serious threat to public health. However, few studies have focused on miRNA-mRNA integration analysis to address the immune mechanisms of macrophage response to A. veronii infection. Herein, we characterized the immunophysiological, biochemical, and transcriptome changes of macrophage under A. veronii infection. We found that macrophages infected with A. veronii released large amounts of cytokines and triggered NLRP3-dependent pyroptosis. Subsequently, 603 differentially expressed miRNAs (DEMIs) and 3693 differentially expressed mRNAs (DEMs) were identified by RNA-seq analysis under A. veronii infection. Moreover, integrated analysis of miRNA-mRNA yielded 66 miRNA-target gene pairs composed of 41 DEMIs and 27 DEMs. We next identified the Toll-like receptor, NOD-like receptor, TNF and NF-κB pathways as necessary for macrophage to respond to A. veronii infection. miR-847 and miR-627 were involved in macrophage response to A. veronii infection by negatively regulating Pannexin-1 and thioredoxin interacting protein (TXNIP). Our findings elucidate the molecular mechanism of macrophage response to A. veronii infection at the miRNA level, providing many candidate miRNAs and mRNAs therapeutic targets for the prevention and treatment of A. veornii infectious diseases.

Hypoxia, hypoxia-inducible factors and inflammatory bowel diseases

Adequate oxygen supply is essential for maintaining the body's normal physiological function. In chronic inflammatory conditions such as inflammatory bowel disease (IBD), insufficient oxygen reaching the intestine triggers the regulatory system in response to environmental changes. However, the pathogenesis of IBD is still under investigation. Recent research has highlighted the significant role of hypoxia in IBD, particularly the involvement of hypoxia-inducible factors (HIF) and their regulatory mechanisms, making them promising therapeutic targets for IBD. This review will delve into the role of hypoxia, HIF, and the associated hypoxia-inflammatory microenvironment in the context of IBD. Potential interventions for addressing these challenging gastrointestinal inflammatory diseases will also be discussed within this framework.

Distinct intratumoral microbiome of young-onset and average-onset colorectal cancer

BACKGROUND

The unexplained rise of young-onset CRC (yoCRC, age <50 years) is of concern. Evidence suggests that microbial dysbiosis may be a contributing factor, but the tumor microbial profile of yoCRC in comparison to average-onset CRC (aoCRC, age >60) has not been fully investigated.

METHODS

16S rRNA amplicon sequencing was performed in tumor and paired adjacent non-malignant fresh frozen tissue specimens prospectively collected from 136 yoCRC and 140 aoCRC patients. Phyloseq, microbiomeSeq, metagenomeSeq, and NetComi were utilized for bioinformatics analysis. Statistical tests included Fisher's exact test, ANOVA, PERMANOVA with Bonferroni correction, linear regression, and Wilcoxon test. p-value <0.05 was considered statistically significant.

FINDINGS

yoCRC patients were more likely to have left-sided (72.8 vs. 54.3%), rectal (36.7% vs. 25%), and stage IV (28% vs. 15%) tumors. yoCRC tumors had significantly higher microbial alpha diversity (p = 1.5 × 10-5) and varied beta diversity (R2 = 0.31, p = 0.013) than aoCRC tumors. yoCRC tumors were enriched with Akkermansia and Bacteroides, whereas aoCRC tumors showed greater relative abundances of Bacillus, Staphylococcus, Listeria, Enterococcus, Pseudomonas, Fusobacterium, and Escherichia/Shigella. Akkermansia had a predominantly negative correlation with the microbial communities in yoCRC tumors. yoCRC and aoCRC tumors had distinct microbial profiles associated with tumor location, sidedness, stage, and obesity. Fusobacterium (R2 = -0.23, p = 0.001) and Akkermansia (R2 = 0.05, p = 0.001) abundance correlated with overall survival in yoCRC.

INTERPRETATION

Our study provides a comprehensive understanding of the microbial perturbations in yoCRC tumors. We identify microbial candidates that may highlight a distinct pathogenesis of yoCRC and serve as preventive, diagnostic, and therapeutic targets.

FUNDING

Sondra and Stephen Hardis Chair in Oncology Research (A.A.K.).

Ocular mucosal homeostasis of teleost fish provides insight into the coevolution between microbiome and mucosal immunity

BACKGROUND

The visual organ plays a crucial role in sensing environmental information. However, its mucosal surfaces are constantly exposed to selective pressures from aquatic or airborne pathogens and microbial communities. Although few studies have characterized the conjunctival-associated lymphoid tissue (CALT) in the ocular mucosa (OM) of birds and mammals, little is known regarding the evolutionary origins and functions of immune defense and microbiota homeostasis of the OM in the early vertebrates.

RESULTS

Our study characterized the structure of the OM microbial ecosystem in rainbow trout (Oncorhynchus mykiss) and confirmed for the first time the presence of a diffuse mucosal-associated lymphoid tissue (MALT) in fish OM. Moreover, the microbial communities residing on the ocular mucosal surface contribute to shaping its immune environment. Interestingly, following IHNV infection, we observed robust immune responses, significant tissue damage, and microbial dysbiosis in the trout OM, particularly in the fornix conjunctiva (FC), which is characterized by the increase of pathobionts and a reduction of beneficial taxa in the relative abundance in OM. Critically, we identified a significant correlation between viral-induced immune responses and microbiome homeostasis in the OM, underscoring its key role in mucosal immunity and microbiota homeostasis.

CONCLUSIONS

Our findings suggest that immune defense and microbiota homeostasis in OM occurred concurrently in early vertebrate species, shedding light on the coevolution between microbiota and mucosal immunity. Video Abstract.

Vasculitis and the NLRP3 inflammasome

PURPOSE OF REVIEW

Vasculitis are a group of heterogeneous conditions characterized by chronic inflammation of blood vessels, leading to tissue destruction and organ failure. Vasculitis is an inflammatory process in which immune effector cells infiltrate blood vessels and surrounding tissues. The involvement of inflammasomes seems to occur during inflammatory processes.

RECENT FINDINGS

Studies have emphasized that genetic susceptibility is an important aspect of the pathogenesis of vasculitis. The innate immune system is a major contributor to these inflammatory diseases, suggesting that the NOD-like receptor family pyrin domain containing 3 (NLRP3) inflammasome plays a key role. NLRP3 activation causes the assembly of a large multiprotein and leads to the secretion of bioactive interleukin (IL)-1β and IL-18 as well as the induction of inflammatory cell death, termed pyroptosis. Accumulating evidence confirms the involvement of this cascade in sterile inflammatory diseases and other vascular diseases.

SUMMARY

In this review, we will summarize the current state of knowledge regarding the role of NLRP3 inflammasome in vascular diseases, and discuss the potential of the NLRP3 inflammasome as a therapeutic target.

Huge anthropogenic microbial load during southwest monsoon season in coastal waters of Kakinada, Bay of Bengal

To examine the influence of anthropogenic activities on the marine ecosystem near the coastal waters of the port city, Kakinada, a study was conducted to investigate the abundance of heterotrophic, indicator and pathogenic bacteria during the spring inter monsoon (SIM) and southwest monsoon (SWM) seasons. A drastic change in the marine bacteria due to the input of allochthonous bacteria during SWM was noticed. An order of magnitude higher abundance of indicators (Escherichia coli and Enterococcus faecalis) and bacterial pathogens (Proteus mirabilis and Pseudomonas aeruginosa) was observed during SWM. In contrast, Chlorophyll-a, heterotrophic bacterial abundance, Aeromonas hydrophila and Klebsiella pneumoniae were higher during SIM. A significant increase in some of the indicator and pathogenic bacterial abundance due to moderate rainfall suggests that the improper drainage system in the city could spread these bacteria, posing a considerable threat to both environment and human health.

Cytotoxicity and Antimicrobial Resistance of Aeromonas Strains Isolated from Fresh Produce and Irrigation Water

The genus Aeromonas has received constant attention in different areas, from aquaculture and veterinary medicine to food safety, where more and more frequent isolates are occurring with increased resistance to antibiotics. The present paper studied the interaction of Aeromonas strains isolated from fresh produce and water with different eukaryotic cell types with the aim of better understanding the cytotoxic capacity of these strains. To study host-cell pathogen interactions in Aeromonas, we used HT-29, Vero, J774A.1, and primary mouse embryonic fibroblasts. These interactions were analyzed by confocal microscopy to determine the cytotoxicity of the strains. We also used Galleria mellonella larvae to test their pathogenicity in this experimental model. Our results demonstrated that two strains showed high cytotoxicity in epithelial cells, fibroblasts, and macrophages. Furthermore, these strains showed high virulence using the G. mellonella model. All strains used in this paper generally showed low levels of resistance to the different families of the antibiotics being tested. These results indicated that some strains of Aeromonas present in vegetables and water pose a potential health hazard, displaying very high in vitro and in vivo virulence. This pathogenic potential, and some recent concerning findings on antimicrobial resistance in Aeromonas, encourage further efforts in examining the precise significance of Aeromonas strains isolated from foods for human consumption.

Gut microbiota-derived metabolites mediate the neuroprotective effect of melatonin in cognitive impairment induced by sleep deprivation

Sleep loss is a serious global health concern. Consequences include memory deficits and gastrointestinal dysfunction. Our previous research showed that melatonin can effectively improve cognitive impairment and intestinal microbiota disturbances caused by sleep deprivation (SD). The present study further explored the mechanism by which exogenous melatonin prevents SD-induced cognitive impairments. Here, we established fecal microbiota transplantation, Aeromonas colonization and LPS or butyrate supplementation tests to evaluate the role of the intestinal microbiota and its metabolites in melatonin in alleviating SD-induced memory impairment.  RESULTS: Transplantation of the SD-gut microbiota into normal mice induced microglia overactivation and neuronal apoptosis in the hippocampus, cognitive decline, and colonic microbiota disorder, manifesting as increased levels of Aeromonas and LPS and decreased levels of Lachnospiraceae_NK4A136 and butyrate. All these events were reversed with the transplantation of SD + melatonin-gut microbiota. Colonization with Aeromonas and the addition of LPS produced an inflammatory response in the hippocampus and spatial memory impairment in mice. These changes were reversed by supplementation with melatonin, accompanied by decreased levels of Aeromonas and LPS. Butyrate administration to sleep-deprived mice restored inflammatory responses and memory impairment. In vitro, LPS supplementation caused an inflammatory response in BV2 cells, which was improved by butyrate supplementation. This ameliorative effect of butyrate was blocked by pretreatment with MCT1 inhibitor and HDAC3 agonist but was mimicked by TLR4 and p-P65 antagonists.  CONCLUSIONS: Gut microbes and their metabolites mediate the ameliorative effects of melatonin on SD-induced cognitive impairment. A feasible mechanism is that melatonin downregulates the levels of Aeromonas and constituent LPS and upregulates the levels of Lachnospiraceae_NK4A136 and butyrate in the colon. These changes lessen the inflammatory response and neuronal apoptosis in the hippocampus through crosstalk between the TLR4/NF-κB and MCT1/ HDAC3 signaling pathways. Video Abstract.

A. caviae infection triggers IL-1β secretion through activating NLRP3 inflammasome mediated by NF-κB signaling pathway partly in a TLR2 dependent manner

Aeromonas caviae, an important food-borne pathogen, induces serious invasive infections and inflammation. The pro-inflammatory IL-1β functions against pathogenic infections and is elevated in various Aeromonas infection cases. However, the molecular mechanism of A. caviae-mediated IL-1β secretion remains unknown. In this study, mouse macrophages (PMs) were used to establish A. caviae infection model and multiple strategies were utilized to explore the mechanism of IL-1β secretion. IL-1β was elevated in A. caviae infected murine serum, PMs lysates or supernatants. This process triggered NLRP3 levels upregulation, ASC oligomerization, as well as dot gathering of NLRP3 and speck-like signals of ASC in the cytoplasm. MCC950 blocked A. caviae mediated IL-1β release. Meanwhile, NLRP3 inflammasome mediated the release of IL-1β in dose- and time-dependent manners, and the release of IL-1β was dependent on active caspase-1, as well as NLRP3 inflammasome was activated by potassium efflux and cathepsin B release ways. A. caviae also enhanced TLR2 levels, and deletion of TLR2 obviously decreased IL-1β secretion. What’s more, A. caviae resulted in NF-κB p65 nuclear translocation partly in a TLR2-dependent manner. Blocking NF-κB using BAY 11-7082 almost completely inhibited NLRP3 inflammasome first signal pro-IL-1β expression. Blocking TLR2, NF-κB, NLRP3 inflammasome significantly downregulated IL-1β release and TNF-α and IL-6 levels. These data illustrate that A. caviae caused IL-1β secretion in PMs is controlled by NLRP3 inflammasome, of which is mediated by NF-κB pathway and is partially dependent on TLR2, providing basis for drugs against A. caviae.