Leptospira-specific immunoglobulin Y (IgY) is protective in infected hamsters

Leptospirosis, a globally significant zoonotic disease caused by pathogenic Leptospira, continues to threaten the health and public safety of both humans and animals. Current clinical treatment of leptospirosis mainly relies on antibiotics but their efficacy in severe cases is controversial. Passive immunization has a protective effect in the treatment of infectious diseases. In addition, chicken egg yolk antibody (IgY) has gained increasing attention as a safe passive immunization agent. This study aimed to investigate whether hens produce specific IgY after immunization with inactivated Leptospira and the protective effect of specific IgY against leptospirosis. First, it was demonstrated that specific IgY could be extracted from the eggs of hens vaccinated with inactivated Leptospira and that specific IgY can specifically recognize and bind homotypic Leptospira with a high titre, as shown by MAT and ELISA. Next, we tested the therapeutic effects of IgY in early and late leptospirosis using a hamster model. The results showed that early specific IgY treatment increased the survival rate of hamsters to 100%, alleviated pathological damage to the liver, kidney, and lung, reduced leptospiral burden, and restored haematological indices as well as functional indicators of the liver and kidney. The therapeutic effect of early specific IgY was comparable to that of doxycycline. Late IgY treatment also enhanced the survival rate of hamsters and improved the symptoms of leptospirosis similar to early IgY treatment. However, the therapeutic effect of late IgY treatment was better when combined with doxycycline. Furthermore, no Leptospira colonization was observed in the kidneys, livers, or lungs of the surviving hamsters treated with specific IgY. Mechanistically, IgY was found to inhibit the growth and adhesion to cells of Leptospira. In conclusion, passive immunotherapy with specific IgY can be considered an effective treatment for leptospirosis, and may replace antibiotics regarding its therapeutic effects.

Transcriptome Analysis of Host Anti-Vibrio harveyi Infection Revealed the Pathogenicity of V. harveyi to American Eel (Anguilla rostrata)

Vibrio harveyi, a recently discovered pathogenic bacterium isolated from American eels (Anguilla rostrata), poses uncertainties regarding its pathogenesis in American eel and the molecular mechanisms underlying host defense against V. harveyi infection. This study aimed to determine the LD50 of V. harveyi in American eel and assess the bacterial load in the liver, spleen, and kidney post-infection with the LD50 dose. The results showed that the LD50 of V. harveyi via intraperitoneal injection in American eels over a 14d period was determined to be 1.24 × 103 cfu/g body weight (6.2 × 104 cfu/fish). The peak bacterial load occurred at 36 h post-infection (hpi) in all three organs examined. Histopathology analysis revealed hepatic vein congestion and thrombi, tubular vacuolar degeneration, and splenic bleeding. Moreover, quantitative reverse transcription polymerase chain reaction (qRT-PCR) results indicated significant up or downregulation of 18 host immune- or anti-infection-related genes post 12 to 60 hpi following the infection. Additionally, RNA sequencing (RNA-seq) unveiled 7 hub differentially expressed genes (DEGs) and 11 encoded proteins play crucial roles in the anti-V. harveyi response in American eels. This study firstly represents the comprehensive report on the pathogenicity of V. harveyi to American eels and RNA-seq of host's response to V. harveyi infection. These findings provide valuable insights into V. harveyi pathogenesis and the strategies employed by the host's immune system at the transcriptomic level to combat V. harveyi infection.

Protective effects of puerarin on liver tissue in Salmonella-infected chicks: a proteomic analysis

Salmonella enterica is a zoonotic bacterium that not only causes serious economic losses to the livestock and poultry industries but also seriously endangers human health. Long-term indiscriminate use of antibiotics has led to drug resistance in Salmonella, and thus the identification of alternatives to antibiotics is crucial. In this study, the effects of puerarin on the S. enterica-infected chickens were investigated. A total of 360 chicks were randomly assigned as the control group (CON), the S. enterica group (S), and puerarin-treatment group (P). Chicks in the P group were fed the basal diet supplemented with 50 (P50), 100 (P100), 200 (P200), and 400 (P400) mg/kg puerarin, respectively. It was found that puerarin treatment markedly altered the serum activities of aspartate aminotransferase (AST), alanine transaminase (ALT), and superoxide dismutase (SOD), together with the malondialdehyde (MDA) and total antioxidant capacity (T-AOC) contents in the serum. The mRNA expression of IL-6, IL-1β, TNF-α, Bcl-2, and caspase-8 in the livers of S. enterica-infected chicks was increased after infection but significantly reduced after treatment with puerarin. Histologic analysis showed that puerarin effectively mitigated morphological damage in the liver caused by S. enterica. Proteomic analysis revealed that S. enterica infection led to metabolic disorders in the liver, resulting in oxidative stress, increased inflammation, and significantly elevated levels of hepatocellular carcinoma biomarkers. The findings of the filtered sequencing were verified by using quantitative PCR (qPCR). Treatment with 100 mg/mL puerarin thus effectively alleviated disordered liver metabolism, reduced inflammation and oxidative damage and significantly reduced the levels of hepatocellular carcinoma biomarkers in the liver. The results suggest that puerarin has the potential to replace antibiotics to control Salmonella infection in poultry and thus improve food safety.

Macrophage superclusters to the rescue

Macrophage aggregates step in to capture blood-borne pathogens in the injured liver.

Exudate From Retail Chicken Liver Packaging Allows for Survival of Naturally Occurring Campylobacter, Coliforms, and Aerobic Microorganisms Under Drying Conditions

Campylobacter spp. are a leading cause of human foodborne illness associated with chicken meat products in the United States. Chicken livers, including exudate from packaging, commonly carry Campylobacter and could be a source of illness if mishandled. Survivability of naturally occurring Campylobacter, total aerobic bacteria, and coliforms was determined under drying conditions in two consumer simulated environments: moist sponge and solid surface. Fresh chicken liver exudate was dispensed onto sponges and glass slides and allowed to dry under ambient conditions for 7 days. Bacterial concentration was measured at 0, 6, 24, 48, 72, and 168 h. Total aerobic population did not decrease by more than one log over 7 days and did not correlate to water activity or time in either simulation. Coliform concentrations increased in sponge simulations but decreased in solid surface simulations. Further, coliform concentrations were significantly higher in sponge simulations than in solid surface. Campylobacter was naturally present in exudate and survived at least to 6 h in every trial. Campylobacter was recoverable at 24 h in some sponge trials. However, Campylobacter concentration was strongly correlated to water activity. Fresh chicken liver exudate could present a risk of campylobacteriosis to consumers if mishandled even after drying.

Cluster of Donor-Derived Cryptococcosis after Liver and Kidney Transplantation

Cryptococcosis infection after transplantation is easily overlooked or misdiagnosed. We report a cluster of donor-derived cryptococcosis infection in liver and kidney transplant recipients from the same donor in China. Infections occurred within 1 month after transplantation, and were confirmed by using biopsies and blood tests.

Tet2 deficiency drives liver microbiome dysbiosis triggering Tc1 cell autoimmune hepatitis

The triggers that drive interferon-γ (IFNγ)-producing CD8 T cell (Tc1 cell)-mediated autoimmune hepatitis (AIH) remain obscure. Here, we show that lack of hematopoietic Tet methylcytosine dioxygenase 2 (Tet2), an epigenetic regulator associated with autoimmunity, results in the development of microbiota-dependent AIH-like pathology, accompanied by hepatic enrichment of aryl hydrocarbon receptor (AhR) ligand-producing pathobionts and rampant Tc1 cell immunity. We report that AIH-like disease development is dependent on both IFNγ and AhR signaling, as blocking either reverts ongoing AIH-like pathology. Illustrating the critical role of AhR-ligand-producing pathobionts in this condition, hepatic translocation of the AhR ligand indole-3-aldehyde (I3A)-releasing Lactobacillus reuteri is sufficient to trigger AIH-like pathology. Finally, we demonstrate that I3A is required for L. reuteri-induced Tc1 cell differentiation in vitro and AIH-like pathology in vivo, both of which are restrained by Tet2 within CD8 T cells. This AIH-disease model may contribute to the development of therapeutics to alleviate AIH.

Within-host evolution of a gut pathobiont facilitates liver translocation

Gut commensal bacteria with the ability to translocate across the intestinal barrier can drive the development of diverse immune-mediated diseases^1-4. However, the key factors that dictate bacterial translocation remain unclear. Recent studies have revealed that gut microbiota strains can adapt and evolve throughout the lifetime of the host^5-9, raising the possibility that changes in individual commensal bacteria themselves over time may affect their propensity to elicit inflammatory disease. Here we show that within-host evolution of the model gut pathobiont Enterococcus gallinarum facilitates bacterial translocation and initiation of inflammation. Using a combination of in vivo experimental evolution and comparative genomics, we found that E. gallinarum diverges into independent lineages adapted to colonize either luminal or mucosal niches in the gut. Compared with ancestral and luminal E. gallinarum, mucosally adapted strains evade detection and clearance by the immune system, exhibit increased translocation to and survival within the mesenteric lymph nodes and liver, and induce increased intestinal and hepatic inflammation. Mechanistically, these changes in bacterial behaviour are associated with non-synonymous mutations or insertion-deletions in defined regulatory genes in E. gallinarum, altered microbial gene expression programs and remodelled cell wall structures. Lactobacillus reuteri also exhibited broadly similar patterns of divergent evolution and enhanced immune evasion in a monocolonization-based model of within-host evolution. Overall, these studies define within-host evolution as a critical regulator of commensal pathogenicity that provides a unique source of stochasticity in the development and progression of microbiota-driven disease.

[LAMTOR2 deficiency exacerbates Klebsiella pneumoniae-induced liver sepsis in mice]

Objective To explore the biological function and mechanisms of LAMTOR2 during Klebsiella pneumoniae(K. pneumoniae) induced liver sepsis by establishing late endosomal/lysosomal adaptor 2(LAMTOR2) gene liver conditional knockout mouse model infected by K. pneumoniae. Methods LAMTOR2 gene liver conditional knockout mice (LAMTOR2^flox/flox; Alb-Cre⁺) and littermate controls (LAMTOR2^flox/flox) were generated and bred. LAMTOR2 gene knockout efficiency in liver was determined by real-time quantitative PCR (RT-qPCR) and Western blot analysis. Then, both group mice were infected with K. pneumoniae, and survival rates and liver pathological changes were determined. The expression levels of liver TNF-α, IL-1β and CXCL1 mRNA were detected by RT-qPCR. Results LAMTOR2 gene liver conditional knockout mice were generated and bred successfully; compared to the littermate controls, LAMTOR2^flox/flox, Alb-Cre⁺ mice showed lower survival rates and more severe liver injury. The expression levels of TNF-α, IL-1β and CXCL1 mRNA were reduced in LAMTOR2^flox/flox and the ability of immune response was decreased in mice. Alb-Cre⁺ mice liver compared to these of littermate controls post K. pneumoniae infections. Conclusion LAMTOR2 plays a protective role during K. pneumoniae-induced liver sepsis.

A lethal model of Leptospira infection in hamster nasal mucosa

Leptospirosis is a fatal zoonosis caused by contact between skin or a mucosal surface and contaminated soil or water. Hamsters were infected by intraperitoneal injection fto establish experimental leptospirosis, which is not a natural route of infection. There are no reports of nasal mucosal infection in hamsters. In this study, infection of the nasal mucosa was performed to establish a model of natural infection. Both methods of infection can cause lethal models with similar symptoms in the later stages of infection, such as weight loss, blood concentration, increased neutrophils (GRAN), and decreased lymphocytes (LYM) in the blood, severe organ damage and liver function obstruction. The burden of Leptospira in the organs and blood was lower in the mucosal inoculation groups at 1 day after infection. However, mucosal infection induced a higher Leptospira burden in urine than intraperitoneal infection in the late stages of infection. After nasal mucosal infection, antibody levels were higher and lasted longer. These results indicated that the route of nasal mucosal infection is a good choice for studying leptospirosis in hamsters.

The establishment of a leptospirosis experimental model is still key to elucidating the pathogenesis of leptospirosis. Hamsters were infected by intraperitoneal injection to establish experimental leptospirosis, although this is not a natural route of infection. The transmission characteristics of Leptospira and the disease progression in hamsters infected by a natural transmission route (e.g. through mucosal surfaces) had not been explored. In this study, we compared the dynamics of Leptospira infection in hamsters inoculated via the nasal mucosa or by intraperitoneal inoculation, and compared the burden of Leptospira and the level of antibodies produced with disease progression, such as body weight, serology, haematological changes and histopathological changes. Our data suggested that there are significant differences in the dynamics of infection between intraperitoneal and mucosal infection pathways. Although the result was the same in the later stage of infection, the course of mucosal infection was slower, which may better recapitulate the natural history of the disease, assist in studying kidney disease caused by Leptospira, and provide an animal model for the study of leptospirosis mucosal immunity.

Polydextrose with and without Bifidobacterium animalis ssp. lactis 420 drives the prevalence of Akkermansia and improves liver health in a multi-compartmental obesogenic mice study

The past two decades of research have raised gut microbiota composition as a contributing factor to the development of obesity, and higher abundance of certain bacterial species has been linked to the lean phenotype, such as Akkermansia muciniphila. The ability of pre- and probiotics to affect metabolic health could be via microbial community alterations and subsequently changes in metabolite profiles, modulating for example host energy balance via complex signaling pathways. The aim of this mice study was to determine how administration of a prebiotic fiber, polydextrose (PDX) and a probiotic Bifidobacterium animalis ssp. lactis 420 (B420), during high fat diet (HFD; 60 kcal% fat) affects microbiota composition in the gastrointestinal tract and adipose tissue, and metabolite levels in gut and liver. In this study C57Bl/6J mice (N = 200) were split in five treatments and daily gavaged: 1) Normal control (NC); 2) HFD; 3) HFD + PDX; 4) HFD + B420 or 5) HFD + PDX + B420 (HFD+S). At six weeks of treatment intraperitoneal glucose-tolerance test (IPGTT) was performed, and feces were collected at weeks 0, 3, 6 and 9. At end of the intervention, ileum and colon mucosa, adipose tissue and liver samples were collected. The microbiota composition in fecal, ileum, colon and adipose tissue was analyzed using 16S rDNA sequencing, fecal and liver metabolomics were performed by nuclear magnetic resonance (NMR) spectroscopy. It was found that HFD+PDX intervention reduced body weight gain and hepatic fat compared to HFD. Sequencing the mice adipose tissue (MAT) identified Akkermansia and its prevalence was increased in HFD+S group. Furthermore, by the inclusion of PDX, fecal, lleum and colon levels of Akkermansia were increased and liver health was improved as the detoxification capacity and levels of methyl-donors were increased. These new results demonstrate how PDX and B420 can affect the interactions between gut, liver and adipose tissue.

Gastrodin attenuates perfluorooctanoic acid-induced liver injury by regulating gut microbiota composition in mice

Perfluorooctanoic acid (PFOA) can accumulate in the livers of humans and animals via the food chain, resulting into liver injury, which is closely related to intestinal flora dysbiosis. Gastrodin has been reported to have hepatoprotective effect. However, whether gastrodin can alleviate PFOA-induced liver injury via modulating gut microbiota remains unclear. Herein, a PFOA-induced liver injury model was established by gavage of PFOA (5 mg/kg body weight) in 2% Tween 80 solution once daily for 6 weeks in mice, and then gastrodin in saline (20 mg/kg body weight) was used once daily for 8 weeks to treat liver damage. The biochemical indexes associated with liver function, oxidative stress, and inflammatory factors were examined. Hematoxylin-eosin staining was used to determine the liver histopathological changes. Besides, 16S rRNA sequencing was used to analyze the difference of gut microbiota between the model and treatment groups. The results showed that gastrodin significantly improved the oxidative stress caused by PFOA. Intestinal flora analysis showed that gastrodin treatment significantly increased the relative abundance of probiotics, such as Lactobacillus, Bifidobacterium, and Bacteroides, while the harmful bacteria, including Desulfovibrio were decreased. Gastrodin treatment also significantly increased the level of short-chain fatty acids (SCFAs), such as butyric acid and isobutyric acid. Spearman correlation analysis showed that the composition changes of gut microbiota and SCFAs increase were both beneficial to alleviate the liver injury caused by PFOA. To sum up, gastrodin can effectively alleviate PFOA-induced liver injury through regulating gut microbiota composition.

NLRP3 Inflammasome Contributes to Host Defense Against Talaromyces marneffei Infection

Talaromyce marneffei is an important thermally dimorphic pathogen causing disseminated mycoses in immunocompromised individuals in southeast Asia. Previous studies have suggested that NLRP3 inflammasome plays a critical role in antifungal immunity. However, the mechanism underlying the role of NLRP3 inflammasome activation in host defense against T. marneffei remains unclear. We show that T. marneffei yeasts but not conidia induce potent IL-1β production. The IL-1β response to T. marneffei yeasts is differently regulated in different cell types; T. marneffei yeasts alone are able to induce IL-1β production in human PBMCs and monocytes, whereas LPS priming is essential for IL-1β response to yeasts. We also find that Dectin-1/Syk signaling pathway mediates pro-IL-1β production, and NLRP3-ASC-caspase-1 inflammasome is assembled to trigger the processing of pro-IL-1β into IL-1β. In vivo, mice deficient in NLRP3 or caspase-1 exhibit higher mortality rate and fungal load compared to wild-type mice after systemic T. marneffei infection, which correlates with the diminished recruitment of CD4 T cells into granulomas in knockout mice. Thus, our study first demonstrates that NLRP3 inflammasome contributes to host defense against T. marneffei infection.

Expeditious recruitment of circulating memory CD8 T cells to the liver facilitates control of malaria

Circulating memory CD8 T cell trafficking and protective capacity during liver-stage malaria infection remains undefined. We find that effector memory CD8 T cells (Tem) infiltrate the liver within 6 hours after malarial or bacterial infections and mediate pathogen clearance. Tem recruitment coincides with rapid transcriptional upregulation of inflammatory genes in Plasmodium-infected livers. Recruitment requires CD8 T cell-intrinsic LFA-1 expression and the presence of liver phagocytes. Rapid Tem liver infiltration is distinct from recruitment to other non-lymphoid tissues in that it occurs both in the absence of liver tissue resident memory "sensing-and-alarm" function and ∼42 hours earlier than in lung infection by influenza virus. These data demonstrate relevance for Tem in protection against malaria and provide generalizable mechanistic insights germane to control of liver infections.

Selenium-enriched Bifidobacterium longum DD98 attenuates irinotecan-induced intestinal and hepatic toxicity in vitro and in vivo

Irinotecan (CPT-11) is a camptothecin chemotherapy drug largely used in treating cancers. However, its strong adverse effects, such as gastrointestinal and hepatic toxicities, tend to reduce the patients' life qualities and to limit the clinical use of CPT-11. The protective roles of selenium (Se) and probiotics against CPT-11-induced toxicity have been widely reported. However, the application of Se-enriched probiotics in the adjuvant therapy of CPT-11 has not been well explored. The purpose of this study is to evaluate the in-vitro and in-vivo effects of Se-enriched Bifidobacterium longum DD98 (Se-B. longum DD98) as a chemotherapy preventive agent on alleviating intestinal and hepatic toxicities induced by CPT-11 chemotherapy. The results showed that Se-B. longum DD98 positively regulated the aberrant cell viability and oxidative stress induced by CPT-11 both in human normal liver (L-02) and rat small intestinal epithelial (IEC-6) cell lines. In vivo experiment revealed that Se-B. longum DD98 significantly attenuated intestinal and hepatic toxicities by ameliorating symptoms such as body weight loss and diarrhea, and by improving the biochemical indicators of hepatotoxicity and oxidative stress. Furthermore, we discovered that the protective effects of Se-B. longum DD98 based largely upon decreasing the pro-inflammatory cytokines IL-1β and IL-18 and enhancing the expression of tight-junction proteins occludin and ZO-1, as well as restoring the composition and diversity of gut microbiota. Results suggested that Se-B. longum DD98 effectively protected livers and intestines against the CPT-11-induced damages, and therefore, could be considered as a promising adjuvant therapeutic agent with CPT-11 for the cancer treatment.

Molecular Characterization and Defense Functions of the Nile Tilapia (Oreochromis niloticus) DnaJ B9b and DnaJ C3a Genes in Response to Pathogenic Bacteria under High-Temperature Stress Conditions

DnaJ proteins or heat shock protein 40s (HSP40s) form one of the largest heat shock protein families. In this study, 2 cDNAs encoding Nile tilapia (Oreochromis niloticus) DnaJ proteins (On-DnaJ B9b and On-DnaJ C3a) were successfully cloned and characterized. The structures and organizations of these two genes are first reported in the present study. On-DnaJ B9b is approximately 2.1 kb long and contains 2 exons and 1 intron, while On-DnaJ C3a is approximately 12 kb long and contains 12 exons and 11 introns. Under normal conditions, On-DnaJ B9b mRNA is highly expressed in gonad and trunk kidney tissues, while On-DnaJ C3a transcripts are abundantly expressed in gills, intestine, liver, and trunk kidney tissues. Following pathogenic infections, the expression of both genes is induced in the liver, spleen and head kidney tissues of Nile tilapia that were infected with two virulent pathogenic bacteria, Streptococcus agalactiae and Flavobacterium columnare. Silencing of these two genes was first carried out, and the results clearly indicated their crucial roles under both heat and bacterial stress conditions. The fundamental knowledge obtained from this study indicates the characteristic basic biofunctions of heat shock proteins in the regulation of intracellular proteins during infection, which involve preventing protein aggregation, promoting protein refolding, and activating unfolded protein degradation.

Flaxseed Powder Attenuates Non-Alcoholic Steatohepatitis via Modulation of Gut Microbiota and Bile Acid Metabolism through Gut-Liver Axis

Non-alcoholic steatohepatitis (NASH) is gradually becoming one of the most common and health-endangering diseases; therefore, it is very important to prevent the occurrence of NASH and prevent simple non-alcoholic fatty liver (NAFL) from further developing into NASH. We fed mice a high-fat diet (HFD, 60% fat) for 14 weeks to induce NAFL and then fed different doses of flaxseed powder (low (10%), middle (20%), and high (30%)) to the mice for 28 weeks. After the animal experiment, we analyzed fecal bile acid (BA) profiles of the HFD mice, flaxseed-fed (FLA-fed) mice, and control mice with a normal diet (10% fat) using a targeted metabolomics approach, and we analyzed the gut microbiota at the same time. We also investigated the mechanistic role of BAs in NASH and identified whether the altered BAs strongly bind to colonic FXR or TGR5. In the present study, we found that 28-week FLA treatment notably alleviated NASH development in NAFL model mice fed with an HFD, and the beneficial effects may be attributed to the regulation of and improvement in the gut flora- and microbiota-related BAs, which then activate the intestinal FXR-FGF15 and TGR5-NF-κB pathways. Our data indicate that FLA might be a promising functional food for preventing NASH through regulating microbiomes and BAs.

Molecular eco-epidemiology of Paracoccidioides brasiliensis in road-killed mammals reveals Cerdocyon thous and Cuniculus paca as new hosts harboring this fungal pathogen

Wild animals infected with Paracoccidioides brasiliensis represent important indicators of this fungal agent presence in the environment. The detection of this pathogen in road-killed wild animals has shown to be a key strategy for eco-epidemiological surveillance of paracoccidioidomycosis (PCM), helping to map hot spots for human infection. Molecular detection of P. brasiliensis in wild animals from PCM outbreak areas has not been performed so far. The authors investigated the presence of P. brasiliensis through nested-PCR in tissue samples obtained from road-killed animals collected nearby a human PCM outbreak spot, Rio de Janeiro state, Brazil and border areas. Eighteen species of mammals were analyzed: Dasypus novemcinctus (nine-banded armadillo, n = 6), Cerdocyon thous (crab-eating fox, n = 4), Coendou spinosus (hairy dwarf porcupine, n = 2), Lontra longicaudis (Neotropical river otter, n = 1), Procyon cancrivorus (crab-eating raccoon, n = 1), Galactis cuja (lesser grison, n = 1), Tamandua tetradactyla (collared anteater, n = 1), Cuniculus paca (paca, n = 1), and Bradypus variegatus (brown-throated three-toed sloth, n = 1). Specific P. brasiliensis sequences were detected in the liver, spleen, and lymph node samples from 4/6 (66.7%) D. novemcinctus, reinforcing the importance of these animals on Paracoccidioides ecology. Moreover, lymph nodes samples from two C. thous, as well as lung samples from the C. paca were also positive. A literature review of Paracoccidioides spp. in vertebrates in Brazil indicates C. thous and C. paca as new hosts for the fungal pathogen P. brasiliensis.

CCR2 Deficiency Impairs Ly6Clo and Ly6Chi Monocyte Responses in Orientia tsutsugamushi Infection

Orientia (O.) tsutsugamushi, the causative agent of scrub typhus, is a neglected, obligate intracellular bacterium that has a prominent tropism for monocytes and macrophages. Complications often involve the lung, where interstitial pneumonia is a typical finding. The severity of scrub typhus in humans has been linked to altered plasma concentrations of chemokines which are known to act as chemoattractants for myeloid cells. The trafficking and function of monocyte responses is critically regulated by interaction of the CC chemokine ligand 2 (CCL2) and its CC chemokine receptor CCR2. In a self-healing mouse model of intradermal infection with the human-pathogenic Karp strain of O. tsutsugamushi, we investigated the role of CCR2 on bacterial dissemination, development of symptoms, lung histology and monocyte subsets in blood and lungs. CCR2-deficient mice showed a delayed onset of disease and resolution of symptoms, higher concentrations and impaired clearance of bacteria in the lung and the liver, accompanied by a slow infiltration of interstitial macrophages into the lungs. In the blood, we found an induction of circulating monocytes that depended on CCR2, while only a small increase in Ly6Chi monocytes was observed in CCR2-/- mice. In the lung, significantly higher numbers of Ly6Chi and Ly6Clo monocytes were found in the C57BL/6 mice compared to CCR2-/- mice. Both wildtype and CCR2-deficient mice developed an inflammatory milieu as shown by cytokine and inos/arg1 mRNA induction in the lung, but with delayed kinetics in CCR2-deficient mice. Histopathology revealed that infiltration of macrophages to the parenchyma, but not into the peribronchial tissue, depended on CCR2. In sum, our data suggest that in Orientia infection, CCR2 drives blood monocytosis and the influx and activation of Ly6Chi and Ly6Clo monocytes into the lung, thereby accelerating bacterial replication and development of interstitial pulmonary inflammation.

Aspergillus flavus induced oxidative stress and immunosuppressive activity in Spodoptera litura as well as safety for mammals

BACKGROUND

In the last few decades, considerable attention has been paid to entomopathogenic fungi as biocontrol agents, however little is known about their mode of action and safety. This study aimed to investigate the toxicity of Aspergillus flavus in insect Spodoptera litura by analyzing the effect of fungal extract on antioxidant and cellular immune defense. In antioxidant defense, the lipid peroxidation (Malondialdehyde content) and antioxidant enzymes activities (Catalase, Ascorbate peroxidase, Superoxide dismutase) were examined. In cellular immune defense, effect of A. flavus extract was analyzed on haemocytes using Scanning Electron Microscopy (SEM). Furthermore, mammalian toxicity was analyzed with respect to DNA damage induced in treated rat relative to control by comet assay using different tissues of rat (blood, liver, and kidney).

RESULTS

Ethyl acetate extract of A. flavus was administrated to the larvae of S.litura using artificial diet method having concentration 1340.84 μg/ml (LC50 of fungus). The effect was observed using haemolymph of insect larvae for different time intervals (24, 48, 72 and 96). In particular, Malondialdehyde content and antioxidant enzymes activities were found to be significantly (p ≤ 0.05) increased in treated larvae as compared to control. A. flavus ethyl acetate extract also exhibit negative impact on haemocytes having major role in cellular immune defense. Various deformities were observed in different haemocytes like cytoplasmic leakage and surface abnormalities etc. Genotoxicity on rat was assessed using different tissues of rat (blood, liver, and kidney) by comet assay. Non-significant effect of A. flavus extract was found in all the tissues (blood, liver, and kidney).

CONCLUSIONS

Overall the study provides important information regarding the oxidative stress causing potential and immunosuppressant nature of A. flavus against S. litura and its non toxicity to mammals (rat), mammals (rat), suggesting it an environment friendly pest management agent.

Evaluation of the Cholesterol-Lowering Mechanism of Enterococcus faecium Strain 132 and Lactobacillus paracasei Strain 201 in Hypercholesterolemia Rats

Hypercholesterolemia can cause many diseases, but it can effectively regulated by Lactobacillus. This study aimed to evaluate the cholesterol-lowering mechanism of Enterococcus faecium strain 132 and Lactobacillusparacasei strain 201. These results showed that both the strains decreased serum total cholesterol (TC), low-density lipoprotein cholesterol (LDL-C), triglycerides (TG), liver TC and TG and increased fecal TC, TG and total bile acid (TBA) levels. Additionally, both strains also reduced glutamic-pyruvic transaminase (ALT), glutamic oxaloacetic transaminase (AST) and levels of tissue inflammation levels to improve the lipid profile, and they reduced fat accumulation partially by alleviating inflammatory responses. Furthermore, both strains regulated the expression of the CYP8B1, CYP7A1, SREBP-1, SCD1 and LDL-R gene to promote cholesterol metabolism and reduce TG accumulation. Interventions with both strains also altered the gut microbiota, and decreasing the abundance of Veillonellaceae, Erysipelotrichaceae and Prevotella. Furthermore, fecal acetic acid and propionic acid were increased by this intervention. Overall, the results suggested that E. faecium strain 132 and L. paracasei strain 201 can alleviate hypercholesterolemia in rats and might be applied as a new type of hypercholesterolemia agent in functional foods.

Monosodium Glutamate Induces Changes in Hepatic and Renal Metabolic Profiles and Gut Microbiome of Wistar Rats

The short- and long-term consumption of monosodium glutamate (MSG) increases urinary pH but the effects on the metabolic pathways in the liver, kidney and the gut microbiota remain unknown. To address this issue, we investigated adult male Wistar rats allocated to receive drinking water with or without 1 g% MSG for 2 weeks (n = 10, each). We performed a Nuclear Magnetic Resonance (NMR) spectroscopy-based metabolomic study of the jejunum, liver, and kidneys, while faecal samples were collected for bacterial DNA extraction to investigate the gut microbiota using 16S rRNA gene sequencing. We observed significant changes in the liver of MSG-treated rats compared to controls in the levels of glucose, pyridoxine, leucine, isoleucine, valine, alanine, kynurenate, and nicotinamide. Among kidney metabolites, the level of trimethylamine (TMA) was increased, and pyridoxine was decreased after MSG-treatment. Sequencing of the 16S rRNA gene revealed that MSG-treated rats had increased Firmicutes, the gut bacteria associated with TMA metabolism, along with decreased Bifidobacterium species. Our data support the impact of MSG consumption on liver and kidney metabolism. Based on the gut microbiome changes, we speculate that TMA and its metabolites such as trimethylamine-N-oxide (TMAO) may be mediators of the effects of MSG on the kidney health.

Association between toothbrushing and non-alcoholic fatty liver disease

Non-alcoholic fatty liver disease (NAFLD) is considered the hepatic manifestation of metabolic syndrome. Periodontitis, as chronic inflammatory destructive disease, is associated metabolic syndromes bidirectionally. Toothbrushing is an essential and important way to manage periodontitis through mechanical removal of biofilm at periodontal tissue. We aimed to assess the association between toothbrushing frequency and the prevalent NAFLD in nationally representative Korean adults. Among adults aged 19 years and older who participated in the Korea National Health and Nutrition Examination Survey in 2010, a total of 6,352 subjects were analyzed. NAFLD was defined as fatty liver index ≥60. Multiple logistic regression analysis was used to estimate multivariable-adjusted odds ratios (ORs) and 95% confidence intervals (CIs). An inverse association between toothbrushing frequency and NAFLD was found. The adjusted ORs (95% CIs) of NALFD was 0.56 (0.35-0.91) in the group who performed toothbrushing ≥ 3 per day compared to the group that performed toothbrushing ≤ 1 per day. For those with toothbrushing frequency ≤1 per day, the adjusted OR (95% CIs) of NAFLD was 2.26 (1.22-4.19) in smokers and 4.52 (1.97-10.38) in subjects with diabetes mellitus (DM), compared to those without the disease and with toothbrushing frequency ≥2 per day, respectively. Our results indicate that higher frequency of toothbrushing is inversely associated with NAFLD. As a modifiable oral habit, regular toothbrushing may be recommended to lower risk of NAFLD, especially in high risk groups such as smokers and diabetic patients.

Brown Seaweed Sargassum siliquosum as an Intervention for Diet-Induced Obesity in Male Wistar Rats

The therapeutic potential of Sargassum siliquosum grown in Australian tropical waters was tested in a rat model of metabolic syndrome. Forty-eight male Wistar rats were divided into four groups of 12 rats and each group was fed a different diet for 16 weeks: corn starch diet (C); high-carbohydrate, high-fat diet (H) containing fructose, sucrose, saturated and trans fats; and C or H diets with 5% S. siliquosum mixed into the food from weeks 9 to 16 (CS and HS). Obesity, hypertension, dyslipidaemia, impaired glucose tolerance, fatty liver and left ventricular fibrosis developed in H rats. In HS rats, S. siliquosum decreased body weight (H, 547 ± 14; HS, 490 ± 16 g), fat mass (H, 248 ± 27; HS, 193 ± 19 g), abdominal fat deposition and liver fat vacuole size but did not reverse cardiovascular and liver effects. H rats showed marked changes in gut microbiota compared to C rats, while S. siliquosum supplementation increased gut microbiota belonging to the family Muribaculaceae. This selective increase in gut microbiota likely complements the prebiotic actions of the alginates. Thus, S. siliquosum may be a useful dietary additive to decrease abdominal and liver fat deposition.

Evaluation of high-resolution melt curve analysis for rapid differentiation of Campylobacter hepaticus from other species in birds

Spotty liver disease (SLD) is a bacterial disease of chicken, causing mortalities and reduction in egg production, hence, contributing to economic loss in the poultry industry. The causative agent of SLD has only recently been identified as a novel Campylobacter species, Campylobacter hepaticus. Specific primers were designed from the hsp60 gene of Campylobacter hepaticus and PCR followed by high-resolution melt curve analysis was optimised to detect and differentiate three species of Campylobacter (Campylobacter coli, Campylobacter jejuni and Campylobacter hepaticus). The three Campylobacter species produced a distinct curve profile and was differentiated using HRM curve analysis. The potential of the PCR-HRM curve analysis was shown in the genotyping of 37 Campylobacter isolates from clinical specimens from poultry farms. PCR-HRM curve analysis of DNA extracts from bile samples or cultures from bile samples, were identified as Campylobacter hepaticus and confirmed by DNA sequencing. The DNA sequence analysis of selected samples from each of the three HRM distinctive curves patterns showed that each DNA sequence was associated with a unique melt profile. The potential of the PCR-HRM curve analysis in genotyping of Campylobacter species was also evaluated using faecal specimens from 100 wild birds. The results presented in this study indicate that PCR followed by HRM curve analysis provides a rapid and robust technique for genotyping of Campylobacter species using either bacterial cultures or clinical specimens.

Effect of Microbial Status on Hepatic Odd-Chain Fatty Acids Is Diet-Dependent

Odd-chain fatty acids (OCFA) are inversely associated with type-2-diabetes in epidemiological studies. They are considered as a biomarker for dairy intake because fermentation in ruminants yields high amounts of propionate, which is used as the primer for lipogenesis. Recently, we demonstrated endogenous OCFA synthesis from propionate in humans and mice, but how this is affected by microbial colonization is still unexplored. Here, we investigated the effect of increasing microbiota complexity on hepatic lipid metabolism and OCFA levels in different dietary settings. Germ-free (GF), gnotobiotic (SIH, simplified human microbiota) or conventional (CONV) C3H/HeOuJ-mice were fed a CHOW or high-fat diet with inulin (HFI) to induce microbial fermentation. We found that hepatic lipogenesis was increased with increasing microbiota complexity, independently of diet. In contrast, OCFA formation was affected by diet as well as microbiota. On CHOW, hepatic OCFA and intestinal gluconeogenesis decreased with increasing microbiota complexity (GF > SIH > CONV), while cecal propionate showed a negative correlation with hepatic OCFA. On HFI, OCFA levels were highest in SIH and positively correlated with cecal propionate. The propionate content in the CHOW diet was 10 times higher than that of HFI. We conclude that bacterial propionate production affects hepatic OCFA formation, unless this effect is masked by dietary propionate intake.

Spontaneous rupture of pyogenic liver abscess with subcapsular hemorrhage mimicking ruptured hepatocellular carcinoma: A case report

RATIONALE

Spontaneous rupture of PLA (pyogenic liver abscess) is an extremely rare and life-threatening event. Ruptured PLA is very difficult to distinguish from malignant HCC (hepatocellular cancer) rupture or cholangiocarcinoma rupture on CT (computed tomography) scan.

PATIENT CONCERNS

We describe the case of a 71-year-old man with fever, right upper abdominal pain, nausea with intermittent vomiting, and general fatigue. He had no medical or surgical history.

DIAGNOSIS

CT scan showed a hypodense mass in right hepatic lobe and MRI (magnetic resonance imaging) revealed a heterogenous mass of ∼6 cm in segment VI of the liver and heterogenous fluid in the subcapsular region. We made a tentative diagnosis of HCC rupture with subcapsular hemorrhage based on these findings.

INTERVENTION

After improving the patient's condition by administering empirical therapy consisting of intravenous antibiotics and fluids, we performed surgical exploration. Gross examination of the abdomen showed that almost the entire right hepatic lobe was hemorrhagic and affected by peritonitis. Therefore, we performed right hepatectomy. The intraoperative frozen biopsy revealed suspicious PLA with marked necrosis, neutrophil infiltration, and hemorrhagic rupture, although no malignant tissue or fungus was observed. The postoperative secondary pathology report confirmed the diagnosis of PLA with hemorrhagic rupture.

OUTCOMES

The patient was discharged 13 days after the operation. Follow-up CT was performed 5 months after discharge and revealed no abnormal findings.

LESSONS

A high index of suspicion is key to preventing misdiagnosis of ruptured PLA and improving prognosis. Furthermore, even if rupture of the PLA is initially localized, delayed peritonitis may occur during medical treatment. Therefore, vigilant monitoring is essential.

Fungal liver infection mimicking hepatic malignant tumor on contrast enhanced ultrasound: A case report

RATIONAL

Fungal liver infection mostly occurs in immunocompromised patients, and is often associated with delayed diagnosis and high mortality rates. Dynamic contrast enhanced imaging is crucial for the diagnosis of fungal liver infection and has been reported having variable manifestations.

PATIENT CONCERNS

A 38-year-old Chinese man, with a history of diabetes and chronic hepatitis B, was admitted to our hospital due to prolonged fever of unknown cause. He had a medical history of receiving broad-spectrum antibiotic treatment for pulmonary inflammation at the local hospital. The blood test results showed that the white cell count (14.0 × 109/L) and neutrophil count ratio (77.0%) were subtly elevated. C-reactive protein (92.0 mg/l) and cancer antigen (CA)-125 (904.50 U/ml) were elevated. Non-small cell lung cancer antigen was within the normal limit. Hepatitis B virus DNA load was 3.28 × 103 IU/ml. Sputum and blood cultures were normal. Abdominal ultrasonography (US) found a large heterogeneous mass, with diffused echogenic foci without infiltrating the surrounding vascular, which exhibiting "rapid wash in and out" on contrast-enhanced ultrasound (CEUS).

DIAGNOSIS

The diagnosis of liver fungal infection was confirmed pathologically via ultrasound-guided biopsy.

INTERVENTIONS

Antibiotic and antifungal therapy with imipenem and voriconazole.

OUTCOMES

The patient's body temperature had been controlled and the huge mass disappeared on follow-up ultrasound 1-year later.

LESSONS

This case highlights the unusual imaging features of fungal liver infection, presenting as huge heterogeneous mass with diffusive echogenic foci without infiltrating the surrounding vascular on grayscale US and the enhancement pattern of "rapid wash in and out" on CEUS. Additionally, ultrasound-guided biopsy is necessary for the correct diagnosis of suspected liver lesions.

Minor Changes in the Composition and Function of the Gut Microbiota During a 12-Week Whole Grain Wheat or Refined Wheat Intervention Correlate with Liver Fat in Overweight and Obese Adults

BACKGROUND

Whole grain wheat (WGW) products are advocated as a healthy choice when compared with refined wheat (RW). One proposed mechanism for these health benefits is via the microbiota, because WGW contains multiple fibers. WGW consumption has been proposed to ameliorate nonalcoholic fatty liver disease, in which microbiota might play a role.

OBJECTIVES

We investigated the effect of WGW compared with RW intervention on the fecal microbiota composition and functionality, and correlated intervention-induced changes in bacteria with changes in liver health parameters in adults with overweight or obesity.

METHODS

We used data of a 12-wk double-blind, randomized, controlled, parallel trial to examine the effects of a WGW (98 g/d) or RW (98 g/d) intervention on the secondary outcomes fecal microbiota composition, predicted microbiota functionality, and stool consistency in 37 women and men (aged 45-70 y, BMI 25-35 kg/m2). The changes in microbiota composition, measured using 16S ribosomal RNA gene sequencing, after a 12-wk intervention were analyzed with nonparametric tests, and correlated with changes in liver fat and circulating concentrations of liver enzymes including alanine transaminase, aspartate transaminase, γ-glutamyltransferase, and serum amyloid A.

RESULTS

The WGW intervention increased the mean (± SD) relative abundances of Ruminococcaceae_UCG-014 (baseline: 2.2 ± 4.6%, differential change over time (Δ) 0.51 ± 4.2%), Ruminiclostridium_9 (baseline: 0.065 ± 0.11%, Δ 0.054 ± 0.14%), and Ruminococcaceae_NK4A214_group (baseline: 0.37 ± 0.56%, Δ 0.17 ± 0.83%), and also the predicted pathway acetyl-CoA fermentation to butyrate II (baseline: 0.23 ± 0.062%, Δ 0.035 ± 0.059%), compared with the RW intervention (P values <0.05). A change in Ruminococcaceae_NK4A214_group was positively correlated with the change in liver fat, in both the WGW (ρ = 0.54; P = 0.026) and RW (ρ = 0.67; P = 0.024) groups.

CONCLUSIONS

In middle-aged overweight and obese adults, a 12-wk WGW intervention increased the relative abundance of a number of bacterial taxa from the family Ruminococcaceae and increased predicted fermentation pathways when compared with an RW intervention. Potential protective health effects of replacement of RW by WGW on metabolic organs, such as the liver, via modulation of the microbiota, deserve further investigation.This trial was registered at clinicaltrials.gov as NCT02385149.

Glutathione-S-transferase alpha-4 in Hippocampus abdominalis (big-belly seahorse): Molecular characterization, antioxidant properties, and its potent immune response

Glutathione-S-transferase (GST) is a key enzyme in the phase-II detoxification process and is a biomarker of oxidative stress. In this study, we analyzed the molecular, biochemical, and antioxidant properties of GST alpha-4 from Hippocampus abdominalis (HaGSTA-4). Also, the spatial and temporal expression of HaGSTA-4 upon immune challenge with abiotic and biotic stimulants were evaluated. The HaGSTA-4 ORF encodes 223 amino acids with a molecular weight of 25.7 kDa, and an estimated isoelectric point (pI) of 8.47. It consists of the GST_C superfamily and thioredoxin-like superfamily domain. The phylogenetic tree revealed that HaGSTA-4 is evolutionarily conserved with its GST alpha class counterparts. From pairwise alignment, the highest values of identity (78.5%) and similarity (85.7%) were with Parambassis ranga GSTA-4. Protein rHaGSTA-4 exhibited the highest conjugation activity towards 1-chloro-2,4-dinitrobenzene (CDNB) at pH 7 and 20 °C. A disk diffusion assay showed that rHaGSTA-4 significantly protects cells from the stress of exposure to ROS inducers such as CuSO₄, CdCl₂, and ZnCl₂. Furthermore, overexpressed HaGSTA-4 defended cells against oxidative stress caused by H₂O₂; evidence of selenium-independent peroxidase activity. From qPCR, the tissue-specific expression profile demonstrates that HaGSTA-4 is most highly expressed in the kidney, followed by the intestine and stomach, among fourteen different tissues extracted from healthy seahorses. The mRNA expression profile of HaGSTA-4 upon immune challenge varied depending on the tissue and the time after challenge. Altogether, this study suggests that HaGSTA-4 may be involved in protection against oxidative stress, in immune defense regulation, and xenobiotic metabolism.

Bactericidal Permeability Increasing Protein Deficiency Aggravates Acute Colitis in Mice by Increasing the Serum Levels of Lipopolysaccharide

Objective

The objective of this study was to understand the role of bactericidal permeability increasing protein (BPI) in the pathogenesis of experimental murine colitis.

Methods

We used the Cre-LoxP system to generate BPI knockout (BPI KO) mice. Acute colitis was induced in BPI KO mice and wild-type (WT) mice by subjecting the mice to 5% dextran sulfate sodium (DSS). Mice were observed for symptoms of experimental colitis. The survival of BPI KO mice to infection with Acinetobacter baumannii, a gram-negative bacterium, was also assessed.

Results

Southern blot, RT-PCR, and western blot results showed that the 2nd and 3rd exons of the murine Bpi gene were knocked out systemically, confirming successful construction of the BPI KO mouse. BPI KO mice subjected to DSS showed increased symptoms of experimental colitis, increased colonic mucosal damage, increased epithelial permeability, elevated levels of serum LPS, and a disrupted fecal microbiome as compared with WT mice. Furthermore, BPI KO mice challenged intraperitoneally with A. baumannii died sooner than WT mice, and the total number of bacteria in the abdominal cavity, spleen, and liver was increased in BPI KO mice as compared to WT mice.

Conclusions

We successfully generated BPI KO mice. The BPI KO mice developed worse colitis than WT mice by increased colitis symptoms and colonic mucosal damage, elevated levels of serum LPS, and a disrupted microbiome. BPI could be a potential target for treatment of ulcerative colitis in humans.

Developing Tadpole Xenopus laevis as a Comparative Animal Model to Study Mycobacterium abscessus Pathogenicity

Mycobacterium abscessus (Mab) is an emerging, nontuberculosis mycobacterium (NTM) that infects humans. Mab has two morphotypes, smooth (S) and rough (R), related to the production of glycopeptidolipid (GPL), that differ in pathogenesis. To further understand the pathogenicity of these morphotypes in vivo, the amphibian Xenopus laevis was used as an alternative animal model. Mab infections have been previously modeled in zebrafish embryos and mice, but Mab are cleared early from immunocompetent mice, preventing the study of chronic infection, and the zebrafish model cannot be used to model a pulmonary infection and T cell involvement. Here, we show that X. laevis tadpoles, which have lungs and T cells, can be used as a complementary model for persistent Mab infection and pathogenesis. Intraperitoneal (IP) inoculation of S and R Mab morphotypes disseminated to tadpole tissues including liver and lungs, persisting for up to 40 days without significant mortality. Furthermore, the R morphotype was more persistent, maintaining a higher bacterial load at 40 days postinoculation. In contrast, the intracardiac (IC) inoculation with S Mab induced significantly greater mortality than inoculation with the R Mab form. These data suggest that X. laevis tadpoles can serve as a useful comparative experimental organism to investigate pathogenesis and host resistance to M. abscessus.

Production of Murine Macrophages from Hoxb8-Immortalized Myeloblasts: Utility and Use in the Context of Salmonella Infection

Salmonella enterica is a Gram-negative intracellular pathogen that causes a range of life-threatening diseases in humans and animals worldwide. In a systemic infection, the ability of Salmonella to survive/replicate in macrophages, particularly in the liver and spleen, is crucial for virulence. Transformed macrophage cell lines and primary macrophages prepared from mouse bone marrow are commonly used models for the study of Salmonella infection. However, these models raise technical or ethical issues that highlight the need for alternative methods. This chapter describes a technique for immortalizing early hematopoietic progenitor cells derived from wild-type or transgenic mice and using them to produce macrophages. It validates, through a specific example, the interest of this cellular approach for the study of Salmonella infection.

Celastrol ameliorates Propionibacterium acnes/LPS-induced liver damage and MSU-induced gouty arthritis via inhibiting K63 deubiquitination of NLRP3

BACKGROUND

Celastrol, a pentacyclic triterpenoid quinonemethide isolated from several spp. of Celastraceae family, exhibits anti-inflammatory activities in a variety of diseases including arthritis.

PURPOSE

This study aims to investigate whether the inhibition of NLRP3 inflammasome is engaged in the anti-inflammatory activities of celastrol and delineate the underlying mechanism.

METHODS

The influence of celastrol on NLRP3 inflammasome activation was firstly studied in lipopolysaccharide (LPS)-primed mouse bone marrow-derived macrophages (BMDMs) and phorbol 12-myristate 13-acetate (PMA)-primed THP-1 cells treated with nigericin. Reconstituted inflammasome was also established by co-transfecting NLRP3, ASC, pro-caspase-1 and pro-IL-1β in HEK293T cells. The changes of inflammasome components including NLRP3, ASC, pro-caspase-1/caspase-1 and pro-IL-1β/IL-1β were examined by enzyme-linked immunosorbent assay (ELISA), western blotting and immunofluorescence. Furthermore, Propionibacterium acnes (P. acnes)/LPS-induced liver injury and monosodium urate (MSU)-induced gouty arthritis in mice were employed in vivo to validate the inhibitory effect of celastrol on NLRP3 inflammasome.

RESULTS

Celastrol significantly suppressed the cleavage of pro-caspase-1 and pro-IL-1β, while not affecting the protein expressions of NLRP3, ASC, pro-caspase-1 and pro-IL-1β in THP-1 cells, BMDMs and HEK293T cells. Celastrol suppressed NLRP3 inflammasome activation and alleviated P. acnes/LPS-induced liver damage and MSU-induced gouty arthritis. Mechanism study revealed that celastrol could interdict K63 deubiquitination of NLRP3, which may concern interaction of celastrol and BRCA1/BRCA2-containing complex subunit 3 (BRCC3), and thereby prohibited the formation of NLRP3, ASC and pro-caspase-1 complex to block the generation of mature IL-1β.

CONCLUSION

Celastrol suppresses NLRP3 inflammasome activation in P. acnes/LPS-induced liver damage and MSU-induced gouty arthritis via inhibiting K63 deubiquitination of NLRP3, which presents a novel insight into inhibition of celastrol on NLRP3 inflammasome and provides more evidences for its application in the therapy of inflammation-related diseases.

Association of Chronic Opisthorchis Infestation and Microbiota Alteration on Tumorigenesis in Cholangiocarcinoma

Cholangiocarcinoma (CCA) is a common hepatobiliary cancer in East and Southeast Asia. The data of microbiota contribution in CCA are still unclear. Current available reports have demonstrated that an Opisthorchis viverrini (OV) infection leads to dysbiosis in the bile duct. An increase in the commensal bacteria Helicobacter spp. in OV-infected CCA patients is associated with bile duct inflammation, severity of bile duct fibrosis, and cholangiocyte proliferation. In addition, secondary bile acids, major microbial metabolites, can mediate cholangiocyte inflammation and proliferation in the liver. A range of samples from CCA patients (stool, bile, and tumor) showed different degrees of dysbiosis. The evidence from these samples suggests that OV infection is associated with alterations in microbiota and could potentially have a role in CCA. In this comprehensive review, reports from in vitro, in vivo, and clinical studies that demonstrate possible links between OV infection, microbiota, and CCA pathogenesis are summarized and discussed. Understanding these associations may pave ways for novel potential adjunct intervention in gut microbiota in CCA patients.

Microbiota-Dependent Effects of IL-22

Cytokines are important contributors to immune responses against microbial and environmental threats and are of particular importance at epithelial barriers. These interfaces are continuously exposed to external factors and thus require immune components to both protect the host from pathogen invasion and to regulate overt inflammation. Recently, substantial efforts have been devoted to understanding how cytokines act on certain cells at barrier sites, and why the dysregulation of immune responses may lead to pathogenesis. In particular, the cytokine IL-22 is involved in preserving an intact epithelium, maintaining a balanced microbiota and a functioning defense system against external threats. However, a tight regulation of IL-22 is generally needed, since uncontrolled IL-22 production can lead to the progression of autoimmunity and cancer. Our aim in this review is to summarize novel findings on IL-22 and its interactions with specific microbial stimuli, and subsequently, to understand their contributions to the function of IL-22 and the clinical outcome. We particularly focus on understanding the detrimental effects of dysregulated control of IL-22 in certain disease contexts.

Helicobacter genus in the intestine and liver of stray cats: the molecular, histopathological, and immunohistochemical study

OBJECTIVES

The study was designed to determine the presence of Helicobacter genus and three species of H. pylori, H. bilis, and H. canis, in the duodenum, ileum, colon, and liver of stray cats. Moreover, the histopathological and immunohistochemical analyses have been performed.

METHODS

Samples were taken from the duodenum, ileum, colon, and liver of 30 cats for molecular and histopathological evaluations. Polymerase chain reaction was carried out for the detection of the Helicobacter genus in the mentioned samples. Then, species-specific primers were used in Helicobacter-positive samples.

RESULTS

Helicobacter genus prevalence rates in the duodenum, ileum, colon, and liver samples were 50%, 60%, 50%, and 43.3%, respectively. Helicobacter pylori, H. canis, and H. bilis were isolated from at least one tissue of 18 (60%), 13 (43.3%), and 8 (26.7%) of the cats, respectively. Immunohistochemical findings confirmed the presence of bacteria in the intestinal crypt or the mucosal layer of duodenum, ileum, colon, and hepatic sinusoids.

CONCLUSION

In the present study, the concurrent infection of duodenum and liver was noticeable. Furthermore, the high prevalence of H. pylori in cats, as a well-known human pathogen, should be considered. High incidence of Helicobacter in gut and liver of Ahvaz stray cats is noticeable. According to the zoonotic importance of Helicobacter, more studies in the field of treatment and prevention are highly recommended.

Effect of dietary supplementation with yeast Saccharomyces cerevisiae on skin, serum and liver of gilthead seabream (Sparus aurata L)

The effect of dietary supplementation with Saccharomyces cerevisiae on gilthead seabream (Sparus aurata L.) was studied. Four replicates of fish (n = 6) were fed with a commercial diet containing 0 (control, no yeast added) or 10 mg per kilogram of heat-killed (30 min, 60°C) S. cerevisiae. After 4 weeks, half of the fish (two replicates) were injured and continued with the same diet. At 3 and 7 days post-wounding, samples of blood, skin mucus, skin and liver were obtained from each fish. The results showed that calcium concentrations were significantly higher (with respect to control fish) in the serum from fish sampled at 3 days post-wounding, whereas antioxidant enzymes in the skin mucus were altered after wounding (at both 3 and 7 days). Histological analyses revealed oedema, signs of inflammation and white cell recruitment together with a reduction in the epidermis layer in the wounded regions of fish fed control diet. Yeast supplementation did not change growth performance and helped maintain the normal serum calcium concentrations in wounded fish. Furthermore, a reduction in inflammation around wounds in the animals fed yeast with respect to that fed control diet was evident in the histological study. Furthermore, increased levels of stress-related gene expression in liver and skin from wounded fish were obtained. Overall, yeast supplementation seemed to be a functional and appropriate dietary additive to improve skin recovery reducing the stress resulting from wounds.

Detection of Campylobacter jejuni liver dissemination in experimentally colonized turkey poults

Consumption of contaminated poultry products, including chicken livers, is the main source of human campylobacteriosis and approximately 90% of human cases are caused by Campylobacter jejuni subsp. jejuni (C. jejuni). Recent culinary trends that favor undercooked chicken livers may be responsible for outbreaks. Turkey is an emerging human protein source, and poultry livers are commonly prepared in popular cuisine such as pâté. The mechanism of how Campylobacter disseminates to poultry liver tissue is unknown. We have previously demonstrated that certain strains of C. jejuni persistently colonize turkeys with the highest density in the ceca. Whether C. jejuni disseminates to the liver of turkeys following intestinal colonization is unknown. In this study, 45 D of hatch turkey poults were co-housed for 30 D. Five poults were euthanized to screen for Campylobacter colonization, and were free of detectable Campylobacter. The remaining 40 poults were randomly split into 2 rooms, with 20 poults per room. At 35 D of age, poults were inoculated by oral gavage with 1 × 10⁶ cfu of C. jejuni isolate NCTC 11168 or mock-inoculated with sterile medium. Ten poults from each room were euthanized at 7 and 14 D post-inoculation (dpi), and cecal contents and livers were cultured and/or enriched for Campylobacter. Livers were harvested aseptically. The ceca of C. jejuni-inoculated poults were highly colonized at 7 and 14 dpi with approximately 10⁸ cfu/mL of cecal contents. At 7 and 14 dpi, 3 and 5 of 10 liver samples were positive for C. jejuni culture (8.6 × 10³ cfu/g of liver ± 4.43 × 10³ and 5.10 × 10³ cfu/g of liver ± 1.74 × 10³), respectively. At 14 dpi, liver samples were cultured by enrichment, and 6 of 10 were positive for Campylobacter. Some liver samples may be below the limit of detection for direct plate culturing. These data determined that turkey liver is a potential reservoir of C. jejuni following intestinal colonization, and identified a potential food safety consideration when turkey liver is prepared for human or pet food consumption.

Supplementation of a propionate-producing consortium improves markers of insulin resistance in an in vitro model of gut-liver axis

Gut-liver cross talk is an important determinant of human health with profound effects on energy homeostasis. While gut microbes produce a huge range of metabolites, specific compounds such as short-chain fatty acids (SCFAs) can enter the portal circulation and reach the liver (Brandl K, Schnabl B. Curr Opin Gastroenterol 33: 128-133, 2017), a central organ involved in glucose homeostasis and diabetes control. Propionate is a major SCFA involved in activation of intestinal gluconeogenesis (IGN), thereby regulating food intake, enhancing insulin sensitivity, and leading to metabolic homeostasis. Although microbiome-modulating strategies may target the increased microbial production of propionate, it is not clear whether such an effect spreads through to the hepatic cellular level. Here, we designed a propionate-producing consortium using a selection of commensal gut bacteria, and we investigated how their delivered metabolites impact an in vitro enterohepatic model of insulin resistance. Glycogen storage on hepatocyte-like cells and inflammatory markers associated with insulin resistance were evaluated to understand the role of gut metabolites on gut-liver cross talk in a simulated scenario of insulin resistance. The metabolites produced by our consortium increased glycogen synthesis by ~57% and decreased proinflammatory markers such as IL-8 by 12%, thus elucidating the positive effect of our consortium on metabolic function and low-grade inflammation. Our results suggest that microbiota-derived products can be a promising multipurpose strategy to modulate energy homeostasis, with the potential ability to assist in managing metabolic diseases due to their adaptability.

Specific pathogens and microbial abundance within liver and kidney tissues of wild marine fish from the Eastern Mediterranean Sea

This study is an initial description and discussion of the kidney and liver microbial communities of five common fish species sampled from four sites along the Eastern Mediterranean Sea shoreline. The goals of the present study were to establish a baseline dataset of microbial communities associated with the tissues of wild marine fish, in order to examine species-specific microbial characteristics and to screen for candidate pathogens. This issue is especially relevant due to the development of mariculture farms and the possible transmission of pathogens from wild to farmed fish and vice versa. Although fish were apparently healthy, 16S rRNA NGS screening identified three potential fish bacterial pathogens: Photobacterium damselae, Vibrio harveyi and Streptococcus iniae. Based on the distribution patterns and relative abundance, 16 samples were classified as potential pathogenic bacteria-infected samples (PPBIS). Hence, PPBIS prevalence was significantly higher in kidneys than in liver samples and variation was found between the fish species. Significant differences were observed between fish species, organs and sites, indicating the importance of the environmental conditions on the fish microbiome. We applied a consistent sampling and analytical method for monitoring in long-term surveys which may be incorporated within other marine fish pathogens surveys around the world.

Large-scale profiling of the proteome and dual transcriptome in Nile tilapia (Oreochromis niloticus) challenged with low- and high-virulence strains of Streptococcus agalactiae

Streptococcus agalactiae is a common pathogen in aquatic animals, especially tilapia, that hinders aquaculture development and leads to serious economic losses. Previously, a S. agalactiae strain named HN016 was identified from infected tilapia, and the attenuated strain YM001 was subsequently obtained by continuous passaging in Tryptic Soy Broth (TSB) medium. YM001 has been demonstrated as a safe vaccine for S. agalactiae infection in tilapia. To understand the molecular bases of the virulence of these two strains, we performed proteomic and transcriptomic analysis to reveal the protein and gene expression changes in the liver and intestine during the infection process. HN016 significantly decreased the contents of white blood cells (WBCs), neutrophils (NEUs), red blood cells (RBCs) and hematocrit (HCT) and increased the levels of total protein (TP), albumin (ALB) and globulin (GLO), while no such significant differences were observed when comparing the control with YM001. During the infection process, pathogenic peptidoglycan hydrolase, CSPA and membrane proteins were significantly differentially expressed between YM001 and HN016. Furthermore, both proteome and transcriptome data showed that the complement and coagulation cascades pathway and the antigen processing and presentation pathway were stimulated in the liver and intestine, respectively, by YM001 infection compared to HN016 infection. The interaction network analysis of key virulence genes from pathogens suggested that CSPA, as a key node, affects the expression of DOLPP1, MIPEP, PA2G4, OCIAD1, G3BP1 and CLIC5 with a positive correlation. The present evidence suggests that during the infection process, CSPA was the key genes contributing to low virulence in YM001.

Expression and functional analysis of Nile tilapia transferrin receptors (TfRs) in host resistance to pathogenic bacteria and iron ion metabolism

Transferrin receptors (TfRs) play an essential role in iron-withholding strategy, and are involved in immune response against bacterial infection. In this study, the transferrin receptor 1 (OnTfR1) and transferrin receptor 2 (OnTfR2) genes are identified and characterized in Nile tilapia (Oreochromis niloticus). The open reading frames of OnTfR1 and OnTfR2 are 2220 and 2343 bp of nucleotide sequence, encoding 739 and 780 amino acids, respectively. The deduced proteins of OnTfR1 and OnTfR2 are highly homologous to those of other species, containing three conserved TfR superfamily domains (PA TfR domain, M28 TfR domain and TfR dimer domain). Expression analyses of OnTfRs in the healthy tilapia reveal that the OnTfR1 and OnTfR2 transcripts are the most abundant in the liver. The in vivo studies show that the expressions of OnTfRs are significantly up-regulate in liver and spleen, following infections of Streptococcus agalactiae and Aeromonas hydrophila. In addition, the in vitro studies reveal that the up-regulations of OnTfR expressions are also significant in monocytes/macrophages and hepatocytes upon the stimulations of S. agalactiae and A. hydrophila. Moreover, the iron ion (Fe³⁺) could significantly increase the expressions of OnTfRs in monocytes/macrophages and hepatocytes. Taken together, the present study indicates that OnTfRs may be involved in host defense against bacterial infection and possess the function of combining or transporting iron ions in Nile tilapia.

Brucella ovis mutant in ABC transporter protects against Brucella canis infection in mice and it is safe for dogs

BACKGROUND/OBJECTIVES

Vaccination is the most important tool for controlling brucellosis, but currently there is no vaccine available for canine brucellosis, which is a zoonotic disease of worldwide distribution caused by Brucella canis. This study aimed to evaluate protection and immune response induced by Brucella ovis ΔabcBA (BoΔabcBA) encapsulated with alginate against the challenge with Brucella canis in mice and to assess the safety of this strain for dogs.

METHODS

Intracellular growth of the vaccine strain BoΔabcBA was assessed in canine and ovine macrophages. Protection induced by BoΔabcBA against virulent Brucella canis was evaluated in the mouse model. Safety of the vaccine strain BoΔabcBA was assessed in experimentally inoculated dogs.

RESULTS

Wild type B. ovis and B. canis had similar internalization and intracellular multiplication profiles in both canine and ovine macrophages. The BoΔabcBA strain had an attenuated phenotype in both canine and ovine macrophages. Immunization of BALB/c mice with alginate-encapsulated BoΔabcBA (108 CFU) induced lymphocyte proliferation, production of IL-10 and IFN-γ, and protected against experimental challenge with B. canis. Dogs immunized with alginate-encapsulated BoΔabcBA (109 CFU) seroconverted, and had no hematologic, biochemical or clinical changes. Furthermore, BoΔabcBA was not detected by isolation or PCR performed using blood, semen, urine samples or vaginal swabs at any time point over the course of this study. BoΔabcBA was isolated from lymph nodes near to the site of inoculation in two dogs at 22 weeks post immunization.

CONCLUSION

Encapsulated BoΔabcBA protected mice against experimental B. canis infection, and it is safe for dogs. Therefore, B. ovis ΔabcBA has potential as a vaccine candidate for canine brucellosis prevention.

Structural Changes in the Lungs and Liver of Mice with Experimental Tuberculosis Treated with Liposome-Encapsulated Dextrazide

Male BALB/с mice were intravenously infected with Mycobacterium tuberculosis H37Rv (0.5 ml of 2-week culture). One month later, treatment with liposome-encapsulated dextrazide (LEDZ, a conjugate of isonicotinic acid hydrazide (INH) and 40 kDa oxidized dextran encapsulated in phosphatidylcholine liposomes), INH, or a combination of LEDZ with INH was started. The doses of LEDZ (liposome suspension) and INH were 0.025 ml/10 g body weight and 5 mg/kg body weight, respectively. All the substances were administered 2 times a week via inhalation or intraperitoneally (a total of 40 doses). We studied the number and the size of tuberculous granulomas, the size of destruction foci and inflammatory infiltrates in the lungs and liver, the amount of fibrous connective tissue, and the dynamic of these parameters. LEDZ+INH inhalations were most effective by the therapeutic ratios in comparison with inhalation and intraperitoneal injections of INH.

Prevalence of Coxiella burnetii (Legionellales: Coxiellaceae) Infection Among Wildlife Species and the Tick Hyalomma lusitanicum (Acari: Ixodidae) in a Meso-Mediterranean Ecosystem

Q fever is a worldwide zoonosis caused by Coxiella burnetii (Derrick) Philip. It is a major cause of abortion among sheep and may be responsible for reproductive losses in red deer in Spain. Airborne transmission is the most widespread; however, some studies suggested that ticks may play a role, but little is known about their actual involvement in the C. burnetii cycle. The aim of this study was to determine the role that Hyalomma lusitanicum (Koch) tick plays in the maintenance of this agent among wildlife in the meso-Mediterranean areas. We processed by PCR 53 swabs from wild rabbits, 21 liver samples from red deer, and 236 ticks collected at different stages. Coxiella burnetii DNA was detected in 43.40% of wild rabbits and 38.09% of red deer, supporting the hypothesis that these animals are quite likely to serve as a reservoir in the field. We also found a high prevalence of C. burnetii in ticks (55.66%). It is worth noting that 50.45% of positive ticks were collected from negative hosts, suggesting that the pathogen probably was acquired at a previous tick stage. Our results suggest transstadial transmission, and the presence of bacterial DNA in the offspring of positive female ticks is the first evidence of the transovarial transmission of C. burnetii by H. lusitanicum. Thus, this tick species seems to play an important role as a bridge of infection in the wildlife cycle, although further studies are needed to confirm vector competence.

Critical Role of Lipid Scramblase TMEM16F in Phosphatidylserine Exposure and Repair of Plasma Membrane after Pore Formation

Plasma membrane damage and cell death during processes such as necroptosis and apoptosis result from cues originating intracellularly. However, death caused by pore-forming agents, like bacterial toxins or complement, is due to direct external injury to the plasma membrane. To prevent death, the plasma membrane has an intrinsic repair ability. Here, we found that repair triggered by pore-forming agents involved TMEM16F, a calcium-activated lipid scramblase also mutated in Scott's syndrome. Upon pore formation and the subsequent influx of intracellular calcium, TMEM16F induced rapid "lipid scrambling" in the plasma membrane. This response was accompanied by membrane blebbing, extracellular vesicle release, preserved membrane integrity, and increased cell viability. TMEM16F-deficient mice exhibited compromised control of infection by Listeria monocytogenes associated with a greater sensitivity of neutrophils to the pore-forming Listeria toxin listeriolysin O (LLO). Thus, the lipid scramblase TMEM16F is critical for plasma membrane repair after injury by pore-forming agents.