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The spread of multidrug-resistant strains of Neisseria gonorrhoeae, the etiologic agent of gonorrhea, represents a global health emergency. Therefore, the development of a safe and effective vaccine against gonorrhea is urgently needed. In previous studies, murine monoclonal antibody (mAb) 2C7 was raised against gonococcal lipooligosaccharide (LOS). mAb 2C7 elicits complement-dependent bactericidal activity against gonococci, and its glycan epitope is expressed by almost every clinical isolate. Furthermore, we identified a peptide, cyclic peptide 2 (CP2) that mimicked the 2C7 LOS epitope, elicited bactericidal antibodies in mice, and actively protected in a mouse vaginal colonization model. In this study, we performed structural analyses of mAb 2C7 and its complex with the CP2 peptide by X-ray crystallography, NMR spectroscopy, and molecular dynamics (MD) simulations. The crystal structure of Fab 2C7 bound to CP2 showed that the peptide adopted a beta-hairpin conformation and bound the Fab primarily through hydrophobic interactions. We employed NMR spectroscopy and MD simulations to map the 2C7 epitope and identify the bioactive conformation of CP2. We also used small-angle X-ray scattering (SAXS) and native mass spectrometry to obtain further information about the shape and assembly state of the complex. Collectively, our new structural information suggests strategies for humanizing mAb 2C7 as a therapeutic against gonococcal infection and for optimizing peptide CP2 as a vaccine antigen.
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Glycosylation is the most prominent modification important for vaccines and its specific pattern depends on several factors that need to be considered when developing a new biopharmaceutical. Tailor-made glycosylation can be exploited to develop more effective and safer vaccines; for this reason, a deep understanding of both glycoengineering strategies and glycans structures and functions is required. In this review we discuss the recent advances concerning glycoprotein expression systems and the explanation of glycans immunomodulation mechanisms. Furthermore, we highlight how glycans tune the immunological properties among different vaccines platforms (whole virus, recombinant protein, nucleic acid), also comparing commercially available formulations and describing the state-of-the-art analytical technologies for glycosylation analysis. The whole review stresses the aspect of glycoprotein glycans as a potential tool to overcome nowadays medical needs in vaccine field.
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Glicoproteínas , Polisacáridos , Vacunas Virales , Glicosilación , Humanos , Polisacáridos/química , Vacunas Virales/química , Vacunas Virales/inmunología , Glicoproteínas/química , Glicoproteínas/inmunología , AnimalesRESUMEN
OBJECTIVE: Assessing unclear biliary strictures is challenging. We analyzed the diagnostic performance of radiology, EUS, and ERCP. METHODS: All patients referred for EUS and ERCP to assess an unclear biliary stricture were prospectively included. The data from radiology, EUS, ERCP, and tissue sampling were recorded. The diagnostic modalities were analyzed separately and in combination, with a focus on PSC. RESULTS: Between 2013 and 2020, 78 patients were included; 31% had PSC. A cholangioscopy was not performed in this study. The final diagnosis indicated that the biliary stricture was benign in 62% of the patients and malignant in 38%. The differences among the modalities were numerical, not significant. The modalities showed an accuracy between 78 and 83% in all the patients and between 75 and 83% in the patients with PSC. The combination of radiology and EUS showed the highest sensitivity of 94% in all the patients and a sensitivity of 100% in PSC. Tissue sampling showed the highest specificity of 93% in all patients and 89% in PSC. In 22 cases with combined EUS, ERCP, and tissue sampling, the accuracy, sensitivity, and specificity were 82%, 70%, and 92%, respectively. Minor differences were observed between the intention-to-diagnose analysis and the per-protocol analysis. Adverse events were recorded in 4% of cases. CONCLUSION: The combination of EUS and ERCP with tissue sampling seems to be useful and safe for excluding malignancy in unclear biliary strictures. In cases with a reduced suspicion of malignancy, radiology with an EUS may be sufficient.
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Colangiopancreatografia Retrógrada Endoscópica , Colestasis , Endosonografía , Sensibilidad y Especificidad , Humanos , Masculino , Endosonografía/métodos , Femenino , Persona de Mediana Edad , Anciano , Constricción Patológica/diagnóstico por imagen , Estudios Prospectivos , Colestasis/diagnóstico por imagen , Colestasis/etiología , Adulto , Colangitis Esclerosante/diagnóstico por imagen , Colangitis Esclerosante/complicacionesRESUMEN
Innate immune cells generate a multifaceted antitumor immune response, including the conservation of essential nutrients such as iron. These cells can be modulated by commensal bacteria; however, identifying and understanding how this occurs is a challenge. Here we show that the food commensal Lactiplantibacillus plantarum IMB19 augments antitumor immunity in syngeneic and xenograft mouse tumor models. Its capsular heteropolysaccharide is the major effector molecule, functioning as a ligand for TLR2. In a two-pronged manner, it skews tumor-associated macrophages to a classically active phenotype, leading to generation of a sustained CD8+ T cell response, and triggers macrophage 'nutritional immunity' to deploy the high-affinity iron transporter lipocalin-2 for capturing and sequestering iron in the tumor microenvironment. This process induces a cycle of tumor cell death, epitope expansion and subsequent tumor clearance. Together these data indicate that food commensals might be identified and developed into 'oncobiotics' for a multi-layered approach to cancer therapy.
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Hierro , Microambiente Tumoral , Animales , Hierro/metabolismo , Ratones , Microambiente Tumoral/inmunología , Humanos , Macrófagos Asociados a Tumores/inmunología , Macrófagos Asociados a Tumores/metabolismo , Linfocitos T CD8-positivos/inmunología , Línea Celular Tumoral , Receptor Toll-Like 2/metabolismo , Receptor Toll-Like 2/inmunología , Ratones Endogámicos C57BL , Lipocalina 2/metabolismo , Lipocalina 2/inmunología , Femenino , Simbiosis/inmunología , Macrófagos/inmunología , Macrófagos/metabolismo , Activación de Macrófagos/inmunología , Ratones NoqueadosRESUMEN
Gram-negative bacteria living in marine waters have evolved peculiar adaptation strategies to deal with the numerous stress conditions that characterize aquatic environments. Among the multiple mechanisms for efficient adaptation, these bacteria typically exhibit chemical modifications in the structure of the lipopolysaccharide (LPS), which is a fundamental component of their outer membrane. In particular, the glycolipid anchor to the membrane of marine bacteria LPSs, i.e. the lipid A, frequently shows unusual chemical structures, which are reflected in equally singular immunological properties with potential applications as immune adjuvants or anti-sepsis drugs. In this work, we determined the chemical structure of the lipid A from Cellulophaga pacifica KMM 3664T isolated from the Sea of Japan. This bacterium showed to produce a heterogeneous mixture of lipid A molecules that mainly display five acyl chains and carry a single phosphate and a D-mannose disaccharide on the glucosamine backbone. Furthermore, we proved that C. pacifica KMM 3664T LPS acts as a weaker activator of Toll-like receptor 4 (TLR4) compared to the prototypical enterobacterial Salmonella typhimurium LPS. Our results are relevant to the future development of novel vaccine adjuvants and immunomodulators inspired by marine LPS chemistry.
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Lípido A , Lípido A/química , Receptor Toll-Like 4/metabolismo , Receptor Toll-Like 4/química , Membrana Externa Bacteriana/metabolismo , Membrana Externa Bacteriana/química , Animales , Lipopolisacáridos/química , RatonesRESUMEN
Streptococcus gordonii is a Gram-positive bacterial species that typically colonizes the human oral cavity, but can also cause local or systemic diseases. Serine-rich repeat (SRR) glycoproteins exposed on the S. gordonii bacterial surface bind to sialylated glycans on human salivary, plasma, and platelet glycoproteins, which may contribute to oral colonization as well as endocardial infections. Despite a conserved overall domain organization of SRR adhesins, the Siglec-like binding regions (SLBRs) are highly variable, affecting the recognition of a wide range of sialoglycans. SLBR-N from the SRR glycoprotein of S. gordonii UB10712 possesses the remarkable ability to recognize complex core 2 O-glycans. We here employed a multidisciplinary approach, including flow cytometry, native mass spectrometry, isothermal titration calorimetry, NMR spectroscopy from both protein and ligand perspectives, and computational methods, to investigate the ligand specificity and binding preferences of SLBR-N when interacting with mono- and disialylated core 2 O-glycans. We determined the means by which SLBR-N preferentially binds branched α2,3-disialylated core 2 O-glycans: a selected conformation of the 3'SLn branch is accommodated into the main binding site, driving the sTa branch to further interact with the protein. At the same time, SLBR-N assumes an open conformation of the CD loop of the glycan-binding pocket, allowing one to accommodate the entire complex core 2 O-glycan. These findings establish the basis for the generation of novel tools for the detection of specific complex O-glycan structures and pave the way for the design and development of potential therapeutics against streptococcal infections.
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Moraxella nonliquefaciens is a commensal of the human upper respiratory tract (URT) but on rare occasions is recovered in cases of ocular, septic and pulmonary infections. Hence there is interest in the pathogenic determinants of M. nonliquefaciens, of which outer membrane (OM) structures such as fimbriae and two capsular polysaccharide (CPS) structures, â3)-ß-D-GalpNAc-(1â5)-ß-Kdop-(2â and â8)-α-NeuAc-(2â, have been reported in the literature. To further characterise its surface virulence factors, we isolated a novel CPS from M. nonliquefaciens type strain CCUG 348T. This structure was elucidated using NMR data obtained from CPS samples that were subjected to various degrees of mild acid hydrolysis. Together with GLC-MS data, the structure was resolved as a linear polymer composed of two GalfNAc residues consecutively added to Kdo, â3)-ß-D-GalfNAc-(1â3)-α-D-GalfNAc-(1â5)-α-(8-OAc)Kdop-(2â. Supporting evidence for this material being CPS was drawn from the proposed CPS biosynthetic locus which encoded a potential GalfNAc transferase, a UDP-GalpNAc mutase for UDP-GalfNAc production and a putative CPS polymerase with predicted GalfNAc and Kdo transferase domains. This study describes a unique CPS composition reported in Moraxella spp. and offers genetic insights into the synthesis and expression of GalfNAc residues, which are rare in bacterial OM glycans.
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Moraxella , Polisacáridos , Humanos , Polisacáridos/análisis , Transferasas/análisis , Uridina Difosfato/análisis , Cápsulas Bacterianas/química , Polisacáridos Bacterianos/químicaRESUMEN
The evaluation of Bacteroides vulgatus mpk (BVMPK) lipopolysaccharide (LPS) recognition by DC-SIGN, a key lectin in mediating immune homeostasis, has been here performed. A fine chemical dissection of BVMPK LPS components, attained by synthetic chemistry combined to spectroscopic, biophysical, and computational techniques, allowed to finely map the LPS epitopes recognized by DC-SIGN. Our findings reveal BVMPK's role in immune modulation via DC-SIGN, targeting both the LPS O-antigen and the core oligosaccharide. Furthermore, when framed within medical chemistry or drug design, our results could lead to the development of tailored molecules to benefit the hosts dealing with inflammatory diseases.
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In this study, we have investigated innate immune activation capacity and metabolic features of a population of P. aeruginosa PAO1 phage-resistant mutants with diverse genetic modification (large genomic deletions and point mutations) arising after exposure to phages targetting lipopolysaccharide (LPS) or Type-4 pili (T4P). Deletions led to the loss of genes involved in LPS synthesis, cell envelope permeability, efflux systems, biofilm production, oxidative stress tolerance, and DNA repair. Loss of LPS O antigen resulted in bacterial sensitivity to serum complement and stimulation of inflammatory cascades but did not cause increased phagocytosis, while T4P phage-resistant mutants were more effectively phagocytized than LPS-defective mutants. Changes in the utilization of different carbon, nitrogen, sulphur, and phosphorus sources were identified, especially in mutants where the two phage DNA persisted in the bacterial population (pseudolysogeny). However, the metabolic changes did not directly correlate with single-gene mutations or the large gene deletions, suggesting they reflect adaptive changes to the gene modifications that arise during the selection of resistant mutants. In contrast, phage-resistant mutants were susceptible to humoral innate immune responses, suggesting that phage resistance may be a beneficial outcome of phage therapy.
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Bacteriófagos , Pseudomonas aeruginosa/metabolismo , Lipopolisacáridos , Bacterias/metabolismo , Inmunidad Innata , MetabolomaRESUMEN
Background: Despite more than 50 years of research and parallel improvements in hepatology and oncology, there is still today neither a treatment to prevent disease progression in primary sclerosing cholangitis (PSC), nor reliable early diagnostic tools for the associated hepatobiliary cancers. Importantly, the limited understanding of the underlying biological mechanisms in PSC and its natural history not only affects the identification of new drug targets but implies a lack of surrogate markers that hampers the design of clinical trials and the evaluation of drug efficacy. The lack of easy access to large representative well-characterised prospective resources is an important contributing factor to the current situation. Methods: We here present the SUPRIM cohort, a national multicentre prospective longitudinal study of unselected PSC patients capturing the representative diversity of PSC phenotypes. We describe the 10-year effort of inclusion and follow-up, an intermediate analysis report including original results, and the associated research resource. All included patients gave written informed consent (recruitment: November 2011-April 2016). Findings: Out of 512 included patients, 452 patients completed the five-year follow-up without endpoint outcomes. Liver transplantation was performed in 54 patients (10%) and hepatobiliary malignancy was diagnosed in 15 patients (3%). We draw a comprehensive landscape of the multidimensional clinical and biological heterogeneity of PSC illustrating the diversity of PSC phenotypes. Performances of available predictive scores are compared and perspectives on the continuation of the SUPRIM cohort are provided. Interpretation: We envision the SUPRIM cohort as an open-access collaborative resource to accelerate the generation of new knowledge and independent validations of promising ones with the aim to uncover reliable diagnostics, prognostic tools, surrogate markers, and new treatment targets by 2040. Funding: This work was supported by the Swedish Cancer Society, Stockholm County Council, and the Cancer Research Funds of Radiumhemmet.
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Enterococcus faecium, a gram-positive opportunistic pathogen, has become a major concern for nosocomial infections due to its resistance to several antibiotics, including vancomycin. Finding novel alternatives for treatment prevention, such as vaccines, is therefore crucial. In this study, we used various techniques to discover a novel capsular polysaccharide. Firstly, we identified an encapsulated E. faecium strain by evaluating the opsonophagocytic activity of fifteen strains with antibodies targeting the well-known lipoteichoic acid antigen. This activity was attributed to an unknown polysaccharide. We then prepared a crude cell wall glycopolymer and fractionated it, guided by immunodot-blot analysis. The most immunoreactive fractions were used for opsonophagocytic inhibition assays. The fraction containing the inhibitory polysaccharide underwent structural characterization using NMR and chemical analyses. The elucidated structure presents a branched repeating unit, with the linear part being: â)-ß-d-Gal-(1 â 4)-ß-d-Glc-(1 â 4)-ß-d-Gal-(1 â 4)-ß-d-GlcNAc-(1â, further decorated with a terminal α-d-Glc and a d-phosphoglycerol moiety, attached to O-2 and O-3 of the 4-linked Gal unit, respectively. This polysaccharide was conjugated to BSA and the synthetic glycoprotein used to immunize mice. The resulting sera exhibited good opsonic activity, suggesting its potential as a vaccine antigen. In conclusion, our effector-function-based approach successfully identified an immunogenic capsular polysaccharide with promising applications in immunotherapy.
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Antígenos Bacterianos , Enterococcus faecium , Ratones , Animales , Antígenos Bacterianos/química , Enterococcus faecium/química , Proteínas Opsoninas , Polisacáridos , Anticuerpos Antibacterianos , Desarrollo de VacunasRESUMEN
Background & Aims: Changes in gut microbiota in metabolic dysfunction-associated steatotic liver disease (MASLD) are important drivers of disease progression towards fibrosis. Therefore, reversing microbial alterations could ameliorate MASLD progression. Oat beta-glucan, a non-digestible polysaccharide, has shown promising therapeutic effects on hyperlipidemia associated with MASLD, but its impact on gut microbiota and most importantly MASLD-related fibrosis remains unknown. Methods: We performed detailed metabolic phenotyping, including assessments of body composition, glucose tolerance, and lipid metabolism, as well as comprehensive characterization of the gut-liver axis in a western-style diet (WSD)-induced model of MASLD and assessed the effect of a beta-glucan intervention on early and advanced liver disease. Gut microbiota were modulated using broad-spectrum antibiotic treatment. Results: Oat beta-glucan supplementation did not affect WSD-induced body weight gain or glucose intolerance and the metabolic phenotype remained largely unaffected. Interestingly, oat beta-glucan dampened MASLD-related inflammation, which was associated with significantly reduced monocyte-derived macrophage infiltration and fibroinflammatory gene expression, as well as strongly reduced fibrosis development. Mechanistically, this protective effect was not mediated by changes in bile acid composition or signaling, but was dependent on gut microbiota and was lost upon broad-spectrum antibiotic treatment. Specifically, oat beta-glucan partially reversed unfavorable changes in gut microbiota, resulting in an expansion of protective taxa, including Ruminococcus, and Lactobacillus followed by reduced translocation of Toll-like receptor ligands. Conclusions: Our findings identify oat beta-glucan as a highly efficacious food supplement that dampens inflammation and fibrosis development in diet-induced MASLD. These results, along with its favorable dietary profile, suggest that it may be a cost-effective and well-tolerated approach to preventing MASLD progression and should be assessed in clinical studies. Impact and Implications: Herein, we investigated the effect of oat beta-glucan on the gut-liver axis and fibrosis development in a mouse model of metabolic dysfunction-associated steatotic liver disease (MASLD). Beta-glucan significantly reduced inflammation and fibrosis in the liver, which was associated with favorable shifts in gut microbiota that protected against bacterial translocation and activation of fibroinflammatory pathways. Together, oat beta-glucan may be a cost-effective and well-tolerated approach to prevent MASLD progression and should be assessed in clinical studies.
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Veillonella parvula, prototypical member of the oral and gut microbiota, is at times commensal yet also potentially pathogenic. The definition of the molecular basis tailoring this contrasting behavior is key for broadening our understanding of the microbiota-driven pathogenic and/or tolerogenic mechanisms that take place within our body. In this study, we focused on the chemistry of the main constituent of the outer membrane of V. parvula, the lipopolysaccharide (LPS). LPS molecules indeed elicit pro-inflammatory and immunomodulatory responses depending on their chemical structures. Herein we report the structural elucidation of the LPS from two strains of V. parvula and show important and unprecedented differences in both the lipid and carbohydrate moieties, including the identification of a novel galactofuranose and mannitol-containing O-antigen repeating unit for one of the two strains. Furthermore, by harnessing computational studies, in vitro human cell models, as well as lectin binding solid-phase assays, we discovered that the two chemically diverse LPS immunologically behave differently and have attempted to identify the molecular determinant(s) governing this phenomenon. Whereas pro-inflammatory potential has been evidenced for the lipid A moiety, by contrast a plausible "immune modulating" action has been proposed for the peculiar O-antigen portion.
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Lipopolisacáridos , Antígenos O , Humanos , Lipopolisacáridos/farmacología , Lipopolisacáridos/metabolismo , Antígenos O/metabolismo , Veillonella/metabolismo , Lípido ARESUMEN
OBJECTIVE: Investigation of serum bile acid profiles in pregnancies complicated by gestational diabetes mellitus (GDM) in a multi-ethnic cohort of women who are lean or obese. DESIGN: Prospective cohort study. SETTING: UK multicentre study. POPULATION: Fasting serum from participants of European or South Asian self-reported ethnicity from the PRiDE study, between 23 and 31 weeks of gestation. METHODS: Bile acids were measured using ultra-performance liquid chromatography-tandem mass spectrometry. Log-transformed data were analysed using linear regression in STATA/IC 15.0. MAIN OUTCOME MEASURES: Total bile acids (TBAs), C4, fasting glucose and insulin. RESULTS: The TBAs were 1.327-fold (1.105-1.594) increased with GDM in European women (P = 0.003). Women with GDM had 1.162-fold (1.002-1.347) increased levels of the BA synthesis marker C4 (P = 0.047). In South Asian women, obesity (but not GDM) increased TBAs 1.522-fold (1.193-1.942, P = 0.001). Obesity was associated with 1.420-fold (1.185-1.702) increased primary/secondary BA ratio (P < 0.001) related to 1.355-fold (1.140-1.611) increased primary BA concentrations (P = 0.001). TBAs were positively correlated with fasting glucose (P = 0.039) in all women, and with insulin (P = 0.001) and the Homeostatic Model Assessment for Insulin Resistance (HOMA-IR) (P = 0.001) in women with GDM. CONCLUSIONS: Serum BA homeostasis in late gestation depends on body mass index and GDM in ethnicity-specific ways. This suggests ethnicity-specific aetiologies may contribute to metabolic risk in European and South Asian women, with the relationship between BAs and insulin resistance of greater importance in European women. Further studies into ethnicity-specific precision medicine for GDM are required.
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Pueblo Asiatico , Ácidos y Sales Biliares , Diabetes Gestacional , Población Blanca , Humanos , Femenino , Diabetes Gestacional/sangre , Diabetes Gestacional/etnología , Embarazo , Ácidos y Sales Biliares/sangre , Adulto , Estudios Prospectivos , Población Blanca/estadística & datos numéricos , Glucemia/metabolismo , Glucemia/análisis , Reino Unido/epidemiología , Obesidad/sangre , Obesidad/etnología , Insulina/sangre , Estudios de Cohortes , Índice de Masa CorporalRESUMEN
BACKGROUND: Interactions between the gut microbiota, diet, and host metabolism contribute to the development of cardiovascular disease, but a firm link between disease-specific gut microbiota alterations and circulating metabolites is lacking. METHODS: We performed shot-gun sequencing on 235 samples from 166 HF patients and 69 healthy control samples. Separate plasma samples from healthy controls (n = 53) were used for the comparison of imidazole propionate (ImP) levels. Taxonomy and functional pathways for shotgun sequencing data was assigned using MetaPhlAn3 and HUMAnN3 pipelines. RESULTS: Here, we show that heart failure (HF) is associated with a specific compositional and functional shift of the gut microbiota that is linked to circulating levels of the microbial histidine-derived metabolite ImP. Circulating ImP levels are elevated in chronic HF patients compared to controls and associated with HF-related gut microbiota alterations. Contrary to the microbiota composition, ImP levels provide insight into etiology and severity of HF and also associate with markers of intestinal permeability and systemic inflammation. CONCLUSIONS: Our findings establish a connection between changes in the gut microbiota, the presence, etiology, and severity of HF, and the gut-microbially produced metabolite ImP. While ImP appears promising as a circulating biomarker reflecting gut dysbiosis related to HF, further studies are essential to demonstrate its causal or contributing role in HF pathogenesis. TRIAL REGISTRATION: NCT02637167, registered December 22, 2015.
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Insuficiencia Cardíaca , Microbiota , Humanos , Disbiosis , Insuficiencia Cardíaca/metabolismo , Imidazoles , Gravedad del PacienteRESUMEN
Due to their ability to recognize carbohydrate structures, lectins emerged as potential receptors for bacterial lipopolysaccharides (LPS). Despite growing interest in investigating the association between host receptor lectins and exogenous glycan ligands, the molecular mechanisms underlying bacterial recognition by human lectins are still not fully understood. We contributed to fill this gap by unveiling the molecular basis of the interaction between the lipooligosaccharide of Escherichia coli and the dendritic cell-specific intracellular adhesion molecules (ICAM)-3 grabbing non-integrin (DC-SIGN). Specifically, a combination of different techniques, including fluorescence microscopy, surface plasmon resonance, NMR spectroscopy, and computational studies, demonstrated that DC-SIGN binds to the purified deacylated R1 lipooligosaccharide mainly through the recognition of its outer core pentasaccharide, which acts as a crosslinker between two different tetrameric units of DC-SIGN. Our results contribute to a better understanding of DC-SIGN-LPS interaction and may support the development of pharmacological and immunostimulatory strategies for bacterial infections, prevention, and therapy.
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Moraxella ovis is a Gram-negative bacterium isolated from sheep conjunctivitis cases and is a rare isolate of infectious bovine keratoconjunctivitis (IBK). This species is closely related to M. bovoculi, another species which can also be isolated from IBK, or cattle upper respiratory tract (URT). Prior to molecular identification techniques, M. bovoculi was frequently misclassified as M. ovis. We previously described the structure of two oligosaccharides (lipooligosaccharide-derived, minor and major glycoforms) from M. bovoculi 237T (type strain, also ATCC BAA-1259T). Here, we have identified the genetic loci for lipooligosaccharide synthesis in M. ovis 354T (NCTC11227) and compared it with M. bovoculi 237T. We identified genes encoding the known glycosyltransferases Lgt6 and Lgt3 in M.ovis. These genes are conserved in Moraxella spp., including M bovoculi. We identified three further putative OS biosynthesis genes that are restricted to M. ovis and M. bovoculi. These encode enzymes predicted to function as GDP-mannose synthases, namely a mannosyltransferase and a glycosyltransferase. Adding insight into the genetic relatedness of M.ovis and M. bovoculi, the M. ovis genes have higher similarity to those in M. bovoculi genotype 2 (nasopharyngeal isolates from asymptomatic cattle), than to M. bovoculi genotype 1 (isolates from eyes of IBK-affected cattle). Sequence analysis confirmed that the predicted mannosyltransferase in M. bovoculi 237T is interrupted by a C>T polymorphism. This mutation is not present in other M. bovoculi strains sequenced to date. We isolated and characterised LOS-derived oligosaccharide from M. ovis 354T. GLC-MS and NMR spectroscopy data revealed a heptasaccharide structure with three ß-D-Glcp residues attached as branches to the central 3,4,6-α-D-Glcp, with subsequent attachment to Kdo. This inner core arrangement is consistent with the action of Lgt6 and Lgt3 glycosyltransferases. Two α-D-Manp residues are linearly attached to the 4-linked ß-D-Glcp, consistent with the presence of the two identified glycosyltransferases. This oligosaccharide structure is consistent with the previously reported minor glycoform isolated from M. bovoculi 237T.
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Queratoconjuntivitis Infecciosa , Lipopolisacáridos , Manosiltransferasas , Animales , Bovinos , Ovinos , Queratoconjuntivitis Infecciosa/microbiología , Moraxella/genética , Glicosiltransferasas/genética , OligosacáridosRESUMEN
BACKGROUND: The impact of gut microbiota and its metabolites on coronary artery disease (CAD) in people with human immunodeficiency virus (PWH) is unknown. Emerging evidence suggests that imidazole propionate (ImP), a microbial metabolite, is linked with cardiometabolic diseases. METHODS: Fecal samples from participants of the Copenhagen Comorbidity in HIV infection (COCOMO) study were processed for 16S rRNA sequencing and ImP measured with liquid chromatography-tandem mass spectrometry. CAD severity was investigated by coronary computed tomography-angiography, and participants grouped according to obstructive CAD (n = 60), nonobstructive CAD (n = 80), or no CAD (n = 114). RESULTS: Participants with obstructive CAD had a gut microbiota with lower diversity and distinct compositional shift, with increased abundance of Rumiococcus gnavus and Veillonella, known producers of ImP. ImP plasma levels were associated with this dysbiosis, and significantly elevated in participants with obstructive CAD. However, gut dysbiosis but not plasma ImP was independently associated with obstructive CAD after adjustment for traditional and HIV-related risk factors (adjusted odds ratio, 2.7; 95% confidence interval, 1.1-7.2; P = .048). CONCLUSIONS: PWH with obstructive CAD displays a distinct gut microbiota profile and increased circulating ImP plasma levels. Future studies should determine whether gut dysbiosis and related metabolites such as ImP are predictive of incident cardiovascular events.
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Enfermedad de la Arteria Coronaria , Microbioma Gastrointestinal , Infecciones por VIH , Imidazoles , Humanos , VIH , Infecciones por VIH/complicaciones , Disbiosis , ARN Ribosómico 16S/genéticaRESUMEN
Introduction: Food allergy (FA) in children is a major health concern. A better definition of the pathogenesis of the disease could facilitate effective preventive and therapeutic measures. Gut microbiome alterations could modulate the occurrence of FA, although the mechanisms involved in this phenomenon are poorly characterized. Gut bacteria release signaling byproducts from their cell wall, such as lipopolysaccharides (LPSs), which can act locally and systemically, modulating the immune system function. Methods: In the current study gut microbiome-derived LPS isolated from fecal samples of FA and healthy children was chemically characterized providing insights into the carbohydrate and lipid composition as well as into the LPS macromolecular nature. In addition, by means of a chemical/MALDI-TOF MS and MS/MS approach we elucidated the gut microbiome-derived lipid A mass spectral profile directly on fecal samples. Finally, we evaluated the pro-allergic and pro-tolerogenic potential of these fecal LPS and lipid A by harnessing peripheral blood mononuclear cells from healthy donors. Results: By analyzing fecal samples, we have identified different gut microbiome-derived LPS chemical features comparing FA children and healthy controls. We also have provided evidence on a different immunoregulatory action elicited by LPS on peripheral blood mononuclear cells collected from healthy donors suggesting that LPS from healthy individuals could be able to protect against the occurrence of FA, while LPS from children affected by FA could promote the allergic response. Discussion: Altogether these data highlight the relevance of gut microbiome-derived LPSs as potential biomarkers for FA and as a target of intervention to limit the disease burden.