STING-dependent trained immunity contributes to host defense against Clostridium perfringens infection via mTOR signaling.

Clostridium perfringens (C. perfringens) infection is recognized as one of the most challenging issues threatening food safety and perplexing agricultural development. To date, the molecular mechanisms of the interactions between C. perfringens and the host remain poorly understood. Here, we show that stimulator of interferon genes (STING)-dependent trained immunity protected against C. perfringens infection through mTOR signaling. Heat-killed Candida albicans (HKCA) training elicited elevated TNF-α and IL-6 production after LPS restimulation in mouse peritoneal macrophages (PM). Although HKCA-trained PM produced decreased levels of TNF-α and IL-6, the importance of trained immunity was demonstrated by the fact that HKCA training resulted in enhanced bacterial phagocytic ability and clearance in vivo and in vitro during C. perfringens infection. Interestingly, HKCA training resulted in the activation of STING signaling. We further demonstrate that STING agonist DMXAA is a strong inducer of trained immunity and conferred host resistance to C. perfringens infection in PM. Importantly, corresponding to higher bacterial burden, reduction in cytokine secretion, phagocytosis, and bacterial killing were shown in the absence of STING after HKCA training. Meanwhile, the high expression levels of AKT/mTOR/HIF1α were indeed accompanied by an activated STING signaling under HKCA or DMXAA training. Moreover, inhibiting mTOR signaling with rapamycin dampened the trained response to LPS and C. perfringens challenge in wild-type (WT) PM after HKCA training. Furthermore, STING­deficient PM presented decreased levels of mTOR signaling-related proteins. Altogether, these results support STING involvement in trained immunity which protects against C. perfringens infection via mTOR signaling.

Dihydroartemisinin is an inhibitor of trained immunity through Akt/mTOR/HIF1α signaling pathway.

Trained immunity is mechanistically defined as the metabolically and epigenetically mediated long-term functional adaptation of the innate immune system, characterized by a heightened response to a secondary stimulation. Given appropriate activation, trained immunity represents an attractive anti-infective therapeutic target. Nevertheless, excessive immune response and subsequent inflammatory cascades may contribute to pathological tissue damage, indicating that the negative impacts of trained immunity appear to be significant. In this study, we show that innate immune responses such as the production of extracellular traps, pro-inflammatory cytokines, and autophagy-related proteins were markedly augmented in trained BMDMs. Furthermore, heat-killed C. albicans priming promotes the activation of the AIM2 inflammasome, and AIM2-/- mice exhibit impaired memory response induced by heat-killed C. albicans. Therefore, we establish that the AIM2 inflammasome is involved in trained immunity and emerges as a promising therapeutic target for potentially deleterious effects. Dihydroartemisinin can inhibit the memory response induced by heat-killed C. albicans through modulation of mTOR signaling and the AIM2 inflammasome. The findings suggest that dihydroartemisinin can reduce the induction of trained immunity by heat-killed C. albicans in C57BL/6 mice. Dihydroartemisinin is one such therapeutic intervention that has the potential to treat of diseases characterized by excessive trained immunity.

Identification and biological characteristics of Enterococcus casseliflavus TN-47 isolated from Monochamus alternatus.

With the widespread use of antibiotics, the incidence of antibiotic resistance in microorganisms has increased. Monochamus alternatus is a trunk borer of pine trees. This study aimed to investigate the in vitro antimicrobial and biological characteristics of Enterococcus casseliflavus TN-47 (PP411196), isolated from the gastrointestinal tract of M. alternatus in Jilin Province, PR China. Among 13 isolates obtained from the insects, five were preliminarily screened for antimicrobial activity. E. casseliflavus TN-47, which exhibited the strongest antimicrobial activity, was identified. E. casseliflavus TN-47 possessed antimicrobial activity against Staphylococcus aureus USA300 and Salmonella enterica serovar Pullorum ATCC 19945. Furthermore, E. casseliflavus TN-47 was sensitive to tetracyclines, penicillins (ampicillin, carbenicillin, and piperacillin), quinolones and nitrofuran antibiotics, and resistant to certain beta-lactam antibiotics (oxacillin, cefradine and cephalexin), macrolide antibiotics, sulfonamides and aminoglycosides. E. casseliflavus TN-47 could tolerate low pH and pepsin-rich conditions in the stomach and grow in the presence of bile acids. E. casseliflavus TN-47 retained its strong auto-aggregating ability and hydrophobicity. This strain did not exhibit any haemolytic activity. These results indicate that E. casseliflavus TN-47 has potential as a probiotic. This study provides a theoretical foundation for the future applications of E. casseliflavus TN-47 and its secondary metabolites in animal nutrition and feed.

Trained immunity in recurrent Staphylococcus aureus infection promotes bacterial persistence.

Bacterial persister cells, a sub-population of dormant phenotypic variants highly tolerant to antibiotics, present a significant challenge for infection control. Investigating the mechanisms of antibiotic persistence is crucial for developing effective treatment strategies. Here, we found a significant association between tolerance frequency and previous infection history in bovine mastitis. Previous S. aureus infection led to S. aureus tolerance to killing by rifampicin in subsequent infection in vivo and in vitro. Actually, the activation of trained immunity contributed to rifampicin persistence of S. aureus in secondary infection, where it reduced the effectiveness of antibiotic treatment and increased disease severity. Mechanically, we found that S. aureus persistence was mediated by the accumulation of fumarate provoked by trained immunity. Combination therapy with metformin and rifampicin promoted eradication of persisters and improved the severity of recurrent S. aureus infection. These findings provide mechanistic insight into the relationship between trained immunity and S. aureus persistence, while providing proof of concept that trained immunity is a therapeutic target in recurrent bacterial infections involving persistent pathogens.

Culturing the Chicken Intestinal Microbiota and Potential Application as Probiotics Development.

Pure cultures of chicken intestinal microbial species may still be crucial and imperative to expound on the function of gut microbiota, and also contribute to the development of potential probiotics and novel bioactive metabolites from gut microbiota. In this study, we isolated and identified 507 chicken intestinal bacterial isolates, including 89 previously uncultured isolates. Among these, a total of 63 Lactobacillus strains, belonging to L. vaginalis, L. crispatus, L. gallinarum, L. reuteri, L. salivarius, and L. saerimneri, exhibited antibacterial activity against S. Pullorum. Acid tolerance tests showed Limosilactobacillus reuteri strain YPG14 (L. reuteri strain YPG14) has a particularly strong tolerance to acid. We further characterized other probiotic properties of L. reuteri strain YPG14. In simulated intestinal fluid, the growth of L. reuteri strain YPG14 remained stable after incubation for 4 h. The auto-aggregation test showed the auto-aggregation percentage of L. reuteri strain YPG14 was recorded as 15.0 ± 0.38%, 48.3 ± 2.51%, and 75.1 ± 4.44% at 3, 12, and 24 h, respectively. In addition, the mucin binding assay showed L. reuteri strain YPG14 exhibited 12.07 ± 0.02% adhesion to mucin. Antibiotic sensitivity testing showed that L. reuteri strain YPG14 was sensitive to the majority of the tested antibiotics. The anti-Salmonella Pullorum (S. Pullorum) infection effect in vivo revealed that the consumption of L. reuteri strain YPG14 could significantly improve body weight loss and survival rate of chicks infected by S. Pullorum; reduce the loads of S. Pullorum in the jejunum, liver, spleen, and feces; and alleviate the jejunum villi morphological structure damage, crypt loss, and inflammatory cell infiltration caused by S. Pullorum. Overall, this study may help us to understand the diversity of chicken intestinal microflora and provide some insights for potential probiotic development from gut microbiota and may find application in the poultry industry.

Longitudinal association between interparental conflict and risk-taking behavior among Chinese adolescents: testing a moderated mediation model.

BACKGROUND: The interparental conflict has been associated with an increased adolescents' engagement in risk-taking behaviors. However, few studies have examined the potential mediation of deviant peer affiliation and the potential moderation of school climate. Grounded in the ecological system theory, this study aimed to explore the mediating role of deviant peer affiliation and the moderating role of school climate between the association of interparental conflict and risk-taking behavior. METHODS: This study conducted a longitudinal design (3 time points, 3 months apart) with the sample comprising 550 middle school students in southeastern China (52.91% males; mean age at Time 1 = 15.37). The performed measurements encompassed interparental conflict (T1), deviant peer affiliation (T2), school climate (T3), risk-taking behavior (T1/T2/T3), and demographic information. RESULTS: The moderated mediation model revealed that after controlling for T1/T2 risk-taking behavior, T1 interparental conflict was longitudinally and positively correlated with T3 risk-taking behavior through T2 deviant peer affiliation. Furthermore, moderated mediation analysis demonstrated that a positive school climate ameliorated the adverse impact of deviant peer affiliation on risk-taking behavior, thereby mitigating the indirect effect of interparental conflict on risk-taking behavior among adolescents. CONCLUSIONS: Our findings propose a nuanced explanation of the processing mechanisms between interparental conflict and risk-taking behaviors among Chinese adolescents. The theoretical and practical implications of the findings are discussed.

IFI204 protects host defense against Staphylococcus aureus-induced pneumonia by promoting extracellular traps formation.

Interferon-inducible protein 204 (IFI204) is an intracellular DNA receptor that can recognize DNA viruses and intracellular bacteria. Extracellular traps (ETs) have been recognized as an indispensable antimicrobial barrier that play an indispensable role in bacterial, fungal, parasitic, and viral infections. However, how ETs form and the mechanisms by which IFI204 function in Staphylococcus aureus pneumonia are still unclear. Moreover, by in vitro experiments, we proved that IFI204 deficiency decreases the formation of ETs induced by Staphylococcus aureus in a NOX-independent manner. More importantly, Deoxyribonuclease I (DNase I) treatment significantly inhibited the formation of ETs. IFI204 contributed to ETs formation by promoting citrullination of histone H3 and the expression of PAD4 (peptidylarginine deiminase 4). Altogether, these findings highlight the potential importance of IFI204 for host defense against S. aureus USA300-TCH1516 infection.

Akkermansia muciniphila Suppresses High-Fat Diet-Induced Obesity and Related Metabolic Disorders in Beagles.

Obesity is one of the prevalent chronic diseases in human and companion animals usually associated with several metabolic disorders. The gut commensal bacterium Akkermansia muciniphila (A. muciniphila) is known for its therapeutic effects on metabolic disorders and inflammations. Here, we isolated the A. muciniphila AKK2 strain from the feces of interferon-inducible protein 204-/- (IFI204-/-) mice and further evaluated its anti-obesity effects on high-fat diet (HFD)-fed C57BL/6J mice and beagles. The results showed that it effectively controlled weight gain. Microbiome analysis using 16S rRNA gene sequencing revealed that HFD alters gut microbiota composition and A. muciniphila AKK2 increases the Firmicutes/Bacteroidetes (F/B) ratio in beagles. Furthermore, we prepared microcapsules containing A. muciniphila AKK2, and tolerance tests showed the encapsulation maintained high viability and stability in an aerobic environment and simulated the secretion of gastrointestinal fluids. Overall, this study widens the spectrum of A. muciniphila applications to prevent obesity.

Purification, Characterization, Mode of Action, and Application of Jileicin, a Novel Antimicrobial from Paenibacillus jilinensis YPG26.

Antimicrobial compounds from the commensal gut microbiota have gained much attention due to their multifunctionality in maintaining good health in the host and killing multidrug-resistant bacteria. Our previous study showed that Paenibacillus jilinensis YPG26 isolated from chicken intestine can antagonize multiple pathogens. Herein, we characterized a bacteriocin-like inhibitory substance, jileicin, purified from P. jilinensis YPG26. Mass spectrometry analysis revealed that jileicin was a protein consisting of 211 amino acids, which showed 88.98% identity to the SIMPL domain-containing protein. The jileicin showed a relatively broad-spectrum antibacterial ability, especially against enterococci. Additionally, the jileicin exhibited good stability after various treatments, no detectable resistance, no significant cytotoxicity, and very low levels of hemolytic activity. The mode of action against Enterococcus faecium demonstrated that jileicin could destroy cell membrane integrity, increase cell membrane permeability, and eventually lead to cell death. Furthermore, jileicin was efficient in controlling the growth of E. faecium in milk. In conclusion, jileicin, as a newly identified antibacterial agent, is expected to be a promising candidate for application in the food, pharmaceutical, and biomedical industries.

Genome mining reveals polysaccharide-degrading potential and new antimicrobial gene clusters of novel intestinal bacterium Paenibacillus jilinensis sp. nov.

BACKGROUND: Drug-resistant bacteria have posed a great threat to animal breeding and human health. It is obviously urgent to develop new antibiotics that can effectively combat drug-resistant bacteria. The commensal flora inhabited in the intestines become potential candidates owing to the production of a wide range of antimicrobial substances. In addition, host genomes do not encode most of the enzymes needed to degrade dietary structural polysaccharides. The decomposition of these polysaccharides mainly depends on gut commensal-derived CAZymes. RESULTS: We report a novel species isolated from the chicken intestine, designated as Paenibacillus jilinensis sp. nov. and with YPG26T (= CCTCC M2020899T) as the type strain. The complete genome of P. jilinensis YPG26T is made up of a single circular chromosome measuring 3.97 Mb in length and containing 49.34% (mol%) G + C. It carries 33 rRNA genes, 89 tRNA genes, and 3871 protein-coding genes, among which abundant carbohydrate-degrading enzymes (CAZymes) are encoded. Moreover, this strain has the capability to antagonize multiple pathogens in vitro. We identified putative 6 BGCs encoding bacteriocin, NRPs, PKs, terpenes, and protcusin by genome mining. In addition, antibiotic susceptibility testing showed sensitivity to all antibiotics tested. CONCLUSIONS: This study highlights the varieties of CAZymes genes and BGCs in the genome of Paenibacillus jilinensis. These findings confirm the beneficial function of the gut microbiota and also provide a promising candidate for the development of new carbohydrate degrading enzymes and antibacterial agents.

Extracellular trap can be trained as a memory response.

Extracellular trap (ET) appears as a double-edged sword for the host since it participates in host immune defense by entrapping pathogens, while excessive ET release also contributes to various diseases progression including atherosclerosis, cancer, and autoimmune disorders. A better understanding of ET formation and regulation will be beneficial for developing strategies for infection control and ET-associated disease treatment. There is some evidence indicating that prior infection can enhance extracellular killing. Neutrophils from cancer or sepsis are predisposed to generate ET. It is reasonable to suspect that ET may be trained to form as a memory response, just like cytokine memory response termed "trained immunity." The mice were intraperitoneally injected with heat-killed Candida albicans (HK-C. albicans), 3 days later bone marrow-derived macrophages (BMDM) were isolated and challenged with Clostridium perfringens as a second stimulation. We found that HK-C. albicans priming enhanced ET formation upon Clostridium perfringens infection, accompanied by increased extracellular killing capacity. Mannan priming also enhanced ET formation. Since ETs memory was induced in chicken PBMC, ETs memory may be evolutionarily conserved. Moreover, mTOR was required for ETs memory response. Collectively, this study showed that ETs can be trained as a memory response and indicated that memory property of ETs should be considered during the understanding of recurrent infection and ET-associated disorders.

Individualized treatment of breast cancer with chronic renal failure: A case report and review of literature.

BACKGROUND: Studies have shown that patients with chronic renal failure (CRF) are more likely to suffer from breast cancer and other malignant tumors. To our knowledge, CRF can reduce drug excretion, thereby increase drug exposure and lead to increased toxicity, which will limit drug treatment and lead to tumor progression. Currently, there are few successful reports on the combination of docetaxel, trastuzumab, and pertuzumab (THP) as a neoadjuvant treatment regimen for breast cancer patients with CRF. CASE SUMMARY: We report a breast cancer (cT2N2M0, Her-2+/HR-) patient with CRF. It was a clinical stage IIIA tumor on the left breast. The patient had suffered from uremia for 2 years, and her heart function was normal. Based on the pathological type, molecular type, and clinical stage of breast cancer, and the patient's renal function, the clinician analyzed the pharmacological and pharmacokinetic characteristics of the antitumor drugs after consulting the relevant literature, and prescribed the neoadjuvant regimen of THP (docetaxel 80 mg/m², trastuzumab 8 mg/kg for the first dose, and 6 mg/kg for the maintenance dose with pertuzumab 840 mg for the first dose and 420 mg for the maintenance dose), once every 3 wk, for a total of 6 courses. The neoadjuvant treatment had a good effect, and the patient then underwent surgery which was uneventful. CONCLUSION: CRF is not a contraindication for systemic treatment and surgery of breast cancer. The THP regimen without dose adjustment may be a safe and effective neoadjuvant treatment for HER-2 positive breast cancer patients with CRF.

GSDMD contributes to host defence against Staphylococcus aureus skin infection by suppressing the Cxcl1-Cxcr2 axis.

Gasdermin D (GSDMD), a member of the gasdermin protein family, is a caspase substrate, and its cleavage is required for pyroptosis and IL-1ß secretion. To date, the role and regulatory mechanism of GSDMD during cutaneous microbial infection remain unclear. Here, we showed that GSDMD protected against Staphylococcus aureus skin infection by suppressing Cxcl1-Cxcr2 signalling. GSDMD deficiency resulted in larger abscesses, more bacterial colonization, exacerbated skin damage, and increased inflammatory cell infiltration. Although GSDMD deficiency resulted in defective IL-1ß production, the critical role of IL-1ß was counteracted by the fact that Caspase-1/11 deficiency also resulted in less IL-1ß production but did not aggravate disease severity during S. aureus skin infection. Interestingly, GSDMD-deficient mice had increased Cxcl1 secretion accompanied by increased recruitment of neutrophils, whereas Caspase-1/11-deficient mice presented similar levels of Cxcl1 and neutrophils as wild-type mice. Moreover, the absence of GSDMD promoted Cxcl1 secretion in bone marrow-derived macrophages induced by live, dead, or different strains of S. aureus. Corresponding to higher transcription and secretion of Cxcl1, enhanced NF-κB activation was shown in vitro and in vivo in the absence of GSDMD. Importantly, inhibiting the Cxcl1-Cxcr2 axis with a Cxcr2 inhibitor or anti-Cxcl1 blocking antibody rescued host defence defects in the GSDMD-deficient mice. Hence, these results revealed an important role of GSDMD in suppressing the Cxcl1-Cxcr2 axis to facilitate pathogen control and prevent tissue damage during cutaneous S. aureus infection.

Chinese public's knowledge, perceived severity, and perceived controllability of COVID-19 and their associations with emotional and behavioural reactions, social participation, and precautionary behaviour: a national survey.

BACKGROUND: The outbreak of the coronavirus disease-19 (COVID-19) has caused enormous stress among the public in China. Intellectual input from various aspects is needed to fight against COVID-19, including understanding of the public's emotion and behaviour and their antecedents from the psychological perspectives. Drawing upon the cognitive appraisal theory, this study examined three cognitive appraisals (i.e., perceived severity, perceived controllability, and knowledge of COVID-19) and their associations with a wide range of emotional and behavioural outcomes among the Chinese public. METHODS: Participants were 4607 citizens (age range: 17-90 years, Mage = 23.71 years) from 31 provinces in China and they took part in a cross-sectional survey online. RESULTS: The results showed that the public's emotional and behavioural reactions were slightly affected by the outbreak of COVID-19. Moreover, the public had limited participation in the events regarding COVID-19 but actively engaged in precautionary behaviour. In addition, results of structural equation model with latent variables revealed that the three appraisals were differentially related to the outcome variables (i.e., negative emotion, positive emotion, sleep problems, aggression, substance use, mobile phone use, social participation, and precautionary behaviour). CONCLUSIONS: The findings highlight the utility of cognitive appraisal, as a core process of coping stress, in explaining the public's emotion and behaviour in the encounter of public health concern. Practically, the findings facilitate the government and practitioners to design and deliver targeted intervention programs to the public.