Publications
49 results found
Routy B, Lenehan JG, Miller WH, et al., 2024, Author Correction: Fecal microbiota transplantation plus anti-PD-1 immunotherapy in advanced melanoma: a phase I trial., Nat Med, Vol: 30
Forlano R, Martinez-Gili L, Takis P, et al., 2024, Disruption of gut barrier integrity and host-microbiome interactions underlie MASLD severity in patients with type-2 diabetes mellitus, Gut Microbes, Vol: 16, ISSN: 1949-0976
Aberration of the “gut-liver axis” contributes to the development and progression of metabolic dysfunction-associated steatotic liver disease (MASLD). Here, we use multi-omics to analyze the gut microbiota composition and metabolic profile of patients with type-2 diabetes mellitus (T2DM). T2DM patients were screened for liver disease by blood tests, ultrasound, and liver stiffness measurements. Stool microbiota was analyzed by 16S rRNA gene sequencing; metabolomic profiling by Nuclear Magnetic Resonance spectroscopy and Ultra-High Performance-Mass Spectrometry. Microbiome and metabolic signatures were analyzed in the whole cohort and in matched subsets to identify signatures specific for steatosis (MASLD±) or fibrosis (Fibrosis±). Gut permeability was assessed in-vitro using monolayers of MDCK cells and trans-epithelial electric resistance (TEER). Cytokine profile was assessed in serum and stools.Overall, 285 patients were enrolled: 255 serum, 252 urine and 97 stool samples were analyzed. Anaeroplasma and Escherichia/Shigella ASVs were higher, while Butyricicoccus ASVs were lower in those with normal liver. In MASLD±, Butyricicoccus ASV was significantly higher in those with steatosis. In the Fibrosis±, Butyricicoccus ASV was significantly lower in those with fibrosis. Glycochenodeoxycholic acid-3-sulfate (G-UDCA-3S) appeared to be higher in MASLD with fibrosis. Fecal water from patients with MASLD and fibrosis caused the greatest drop in the TEER vs those with normal liver; this was reversed with protease inhibitors. Finally, fecal IL-13 was lower in MASLD with fibrosis. We identified microbiome signatures which were specific for steatosis and fibrosis and independent of other metabolic risk factors. Moreover, we conclude that protease-related gut permeability plays a role in those MASLD patients with fibrosis, and that disease progression is linked to a gut-liver axis which is at least partially independent of T2DM.
Quesada-Vázquez S, Castells-Nobau A, Latorre J, et al., 2023, Potential therapeutic implications of histidine catabolism by the gut microbiota in NAFLD patients with morbid obesity., Cell Rep Med, Vol: 4
The gut microbiota contributes to the pathophysiology of non-alcoholic fatty liver disease (NAFLD). Histidine is a key energy source for the microbiota, scavenging it from the host. Its role in NAFLD is poorly known. Plasma metabolomics, liver transcriptomics, and fecal metagenomics were performed in three human cohorts coupled with hepatocyte, rodent, and Drosophila models. Machine learning analyses identified plasma histidine as being strongly inversely associated with steatosis and linked to a hepatic transcriptomic signature involved in insulin signaling, inflammation, and trace amine-associated receptor 1. Circulating histidine was inversely associated with Proteobacteria and positively with bacteria lacking the histidine utilization (Hut) system. Histidine supplementation improved NAFLD in different animal models (diet-induced NAFLD in mouse and flies, ob/ob mouse, and ovariectomized rats) and reduced de novo lipogenesis. Fecal microbiota transplantation (FMT) from low-histidine donors and mono-colonization of germ-free flies with Enterobacter cloacae increased triglyceride accumulation and reduced histidine content. The interplay among microbiota, histidine catabolism, and NAFLD opens therapeutic opportunities.
Andrikopoulos P, Aron-Wisnewsky J, Chakaroun R, et al., 2023, Evidence of a causal and modifiable relationship between kidney function and circulating trimethylamine N-oxide, Nature Communications, Vol: 14, Pages: 1-18, ISSN: 2041-1723
The host-microbiota co-metabolite trimethylamine N-oxide (TMAO) is linked to increased cardiovascular risk but how its circulating levels are regulated remains unclear. We applied “explainable” machine learning, univariate, multivariate and mediation analyses of fasting plasma TMAO concentration and a multitude of phenotypes in 1,741 adult Europeans of the MetaCardis study. Here we show that next to age, kidney function is the primary variable predicting circulating TMAO, with microbiota composition and diet playing minor, albeit significant, roles. Mediation analysis suggests a causal relationship between TMAO and kidney function that we corroborate in preclinical models where TMAO exposure increases kidney scarring. Consistent with our findings, patients receiving glucose-lowering drugs with reno-protective properties have significantly lower circulating TMAO when compared to propensity-score matched control individuals. Our analyses uncover a bidirectional relationship between kidney function and TMAO that can potentially be modified by reno-protective anti-diabetic drugs and suggest a clinically actionable intervention for decreasing TMAO-associated excess cardiovascular risk.
Routy B, Lenehan JG, Miller WH, et al., 2023, Fecal microbiota transplantation plus anti-PD-1 immunotherapy in advanced melanoma: a phase I trial, Nature Medicine, ISSN: 1546-170X
Fecal microbiota transplantation (FMT) represents a potential strategy to overcome resistance to immune checkpoint inhibitors in patients with refractory melanoma; however, the role of FMT in first-line treatment settings has not been evaluated. We conducted a multicenter phase I trial combining healthy donor FMT with the PD-1 inhibitors nivolumab or pembrolizumab in 20 previously untreated patients with advanced melanoma. The primary end point was safety. No grade 3 adverse events were reported from FMT alone. Five patients (25%) experienced grade 3 immune-related adverse events from combination therapy. Key secondary end points were objective response rate, changes in gut microbiome composition and systemic immune and metabolomics analyses. The objective response rate was 65% (13 of 20), including four (20%) complete responses. Longitudinal microbiome profiling revealed that all patients engrafted strains from their respective donors; however, the acquired similarity between donor and patient microbiomes only increased over time in responders. Responders experienced an enrichment of immunogenic and a loss of deleterious bacteria following FMT. Avatar mouse models confirmed the role of healthy donor feces in increasing anti-PD-1 efficacy. Our results show that FMT from healthy donors is safe in the first-line setting and warrants further investigation in combination with immune checkpoint inhibitors. ClinicalTrials.gov identifier NCT03772899.
Balarajah S, Martinez-Gili L, Alexander J, et al., 2023, The South Asian inflammatory bowel disease (IBD) phenotype: ethnic differences demonstrated through analysis of the UK IBD BioResource database, Annual Meeting of the British-Society-of-Gastroenterology (BSG), Publisher: BMJ PUBLISHING GROUP, Pages: A72-A72, ISSN: 0017-5749
Forlano R, Martinez-Gili L, Blanco JM, et al., 2023, Altered gut barrier integrity as a mediator of host-microbiome interactions in diabetic patients with advanced Non-alcoholic fatty liver disease, Publisher: ELSEVIER, Pages: S601-S602, ISSN: 0168-8278
Mullish BH, Martinez Gili L, Allegretti JR, 2023, Editorial: the acid test—can bile acids predict recurrence of Clostridioides difficile infection? Authors' reply, Alimentary Pharmacology and Therapeutics, Vol: 57, Pages: 169-170, ISSN: 0269-2813
Martinez Gili L, Pechlivanis A, McDonald J, et al., 2023, Bacterial and metabolic phenotypes associated with inadequate response to ursodeoxycholic acid treatment in primary biliary cholangitis, Gut Microbes, Vol: 15, Pages: 1-19, ISSN: 1949-0976
Primary biliary cholangitis (PBC) is a chronic cholestatic liver disease with ursodeoxycholic acid (UDCA) as first-line treatment. Poor response to UDCA is associated with a higher risk of progressing to cirrhosis, but the underlying mechanisms are unclear. UDCA modulates the composition of primary and bacterial-derived bile acids (BAs). We characterized the phenotypic response to UDCA based on BA and bacterial profiles of PBC patients treated with UDCA. Patients from the UK-PBC cohort (n = 419) treated with UDCA for a minimum of 12-months were assessed using the Barcelona dynamic response criteria. BAs from serum, urine, and feces were analyzed using Ultra-High-Performance Liquid Chromatography-Mass Spectrometry and fecal bacterial composition measured using 16S rRNA gene sequencing. We identified 191 non-responders, 212 responders, and a subgroup of responders with persistently elevated liver biomarkers (n = 16). Responders had higher fecal secondary and tertiary BAs than non-responders and lower urinary bile acid abundances, with the exception of 12-dehydrocholic acid, which was higher in responders. The sub-group of responders with poor liver function showed lower alpha-diversity evenness, lower abundance of fecal secondary and tertiary BAs than the other groups and lower levels of phyla with BA-deconjugation capacity (Actinobacteriota/Actinomycetota, Desulfobacterota, Verrucomicrobiota) compared to responders. UDCA dynamic response was associated with an increased capacity to generate oxo-/epimerized secondary BAs. 12-dehydrocholic acid is a potential biomarker of treatment response. Lower alpha-diversity and lower abundance of bacteria with BA deconjugation capacity might be associated with an incomplete response to treatment in some patients.
Mullish BH, Martinez Gili L, Chekmeneva E, et al., 2022, Assessing the clinical value of faecal bile acid profiling to predict recurrence in primary Clostridioides difficile infection, Alimentary Pharmacology and Therapeutics, Vol: 56, Pages: 1556-1569, ISSN: 0269-2813
Background:Factors influencing recurrence risk in primary Clostridioides difficile infection (CDI) are poorly understood, and tools predicting recurrence are lacking. Perturbations in bile acids (BAs) contribute to CDI pathogenesis and may be relevant to primary disease prognosis.Aims:To define stool BA dynamics in patients with primary CDI and explore signatures predicting recurrenceMethodsWeekly stool samples were collected from patients with primary CDI from the last day of anti-CDI therapy until recurrence or, otherwise, through 8 weeks post-completion. Ultra-high performance liquid chromatography-mass spectrometry was used to profile BAs; stool bile salt hydrolase (BSH) activity was measured to determine primary BA bacterial deconjugation capacity. Multivariate and univariate models were used to define differential BA trajectories in patients with recurrence versus those without, and to assess faecal BAs as predictive markers for recurrence.Results:Twenty (36%) of 56 patients (median age: 57, 64% male) had recurrence; 80% of recurrences occurred within the first 9 days post-antibiotic treatment. Principal component analysis of stool BA profiles demonstrated clustering by recurrence status and post-treatment timepoint. Longitudinal faecal BA trajectories showed recovery of secondary BAs and their derivatives only in patients without recurrence. BSH activity increased over time only among non-relapsing patients (β = 0.056; likelihood ratio test p = 0.018). A joint longitudinal-survival model identified five stool BAs with area under the receiver operating characteristic curve >0.73 for predicting recurrence within 9 days post-CDI treatment.Conclusions:Gut BA metabolism dynamics differ in primary CDI patients between those developing recurrence and those who do not. Individual BAs show promise as potential novel biomarkers to predict CDI recurrence.
Belda E, Voland L, Tremaroli V, et al., 2022, Impairment of gut microbial biotin metabolism and host biotin status in severe obesity: effect of biotin and prebiotic supplementation on improved metabolism, Gut, Vol: 71, Pages: 2463-2480, ISSN: 0017-5749
Objectives Gut microbiota is a key component in obesity and type 2 diabetes, yet mechanisms and metabolites central to this interaction remain unclear. We examined the human gut microbiome’s functional composition in healthy metabolic state and the most severe states of obesity and type 2 diabetes within the MetaCardis cohort. We focused on the role of B vitamins and B7/B8 biotin for regulation of host metabolic state, as these vitamins influence both microbial function and host metabolism and inflammation.Design We performed metagenomic analyses in 1545 subjects from the MetaCardis cohorts and different murine experiments, including germ-free and antibiotic treated animals, faecal microbiota transfer, bariatric surgery and supplementation with biotin and prebiotics in mice.Results Severe obesity is associated with an absolute deficiency in bacterial biotin producers and transporters, whose abundances correlate with host metabolic and inflammatory phenotypes. We found suboptimal circulating biotin levels in severe obesity and altered expression of biotin-associated genes in human adipose tissue. In mice, the absence or depletion of gut microbiota by antibiotics confirmed the microbial contribution to host biotin levels. Bariatric surgery, which improves metabolism and inflammation, associates with increased bacterial biotin producers and improved host systemic biotin in humans and mice. Finally, supplementing high-fat diet-fed mice with fructo-oligosaccharides and biotin improves not only the microbiome diversity, but also the potential of bacterial production of biotin and B vitamins, while limiting weight gain and glycaemic deterioration.Conclusion Strategies combining biotin and prebiotic supplementation could help prevent the deterioration of metabolic states in severe obesity.Trial registration number NCT02059538.
Routy B, Lenehan J, Daisley B, et al., 2022, 614 Microbiome modification with fecal microbiota transplant from healthy donors before anti-PD1 therapy reduces primary resistance to immunotherapy in advanced and metastatic melanoma patients, SITC 37th Annual Meeting (SITC 2022) Abstracts, Publisher: BMJ Publishing Group Ltd
Forlano R, Mullish BH, Martinez-Gili L, et al., 2022, Factors associated with increased gut permeability and severity of liver disease in diabetic patients with NAFLD, The International Liver CongressTM 2022, Publisher: Elsevier, Pages: S674-S675, ISSN: 0168-8278
Forlano R, Mullish BH, Martinez-Gili L, et al., 2022, Factors associated with increased gut permeability and severity of liver disease in diabetic patients with NAFLD, Digestive Disease Week® (DDW) 2022, Publisher: Elsevier, Pages: S1136-S1136, ISSN: 0016-5085
Blanco JM, Danckert NP, Liu Z, et al., 2022, New links between psoriatic arthritis and the gut microbiome suggest a stronger role of the gut-joint axis, Digestive Disease Week® (DDW) 2022, Publisher: Elsevier, Pages: S456-S457, ISSN: 0016-5085
Martinez-Gili L, Gordon H, Blad W, et al., 2022, Disease location and activity impact serum and urine amino acids but not oxylipins in twins with inflammatory bowel disease, Digestive Disease Week® (DDW) 2022, Publisher: Elsevier, Pages: S796-S796, ISSN: 0016-5085
Martinez-Gili L, Gordon H, Blad W, et al., 2022, Gut bacteria composition and familiality echo Inflammatory Bowel Disease type and pathological spectrum, 17th Congress of ECCO, Publisher: Oxford University Press, Pages: I601-I602, ISSN: 1873-9946
BackgroundInflammatory bowel disease (IBD) aetiology encompasses genetic and environmental factors. Twin studies provide valuable insights to the familial degree (shared genetics and environment) of observed phenotypes. We characterised the gut bacterial composition of twins with IBD to find taxa associated with disease and estimate their familiality.MethodsFaecal samples were collected from 88 monozygotic (MZ) and dizygotic (DZ) twin pairs concordant or discordant for Crohn’s disease (CD; 26 MZ; 19 DZ) or ulcerative colitis (UC; 16 MZ; 27 DZ). The 16S rRNA gene was sequenced and amplicon sequence variants (ASV) generated. ANCOM software was used to assess differences in IBD vs. non-IBD, stratifying by disease type (CD/UC) and adjusting for age, gender and smoking. Twin pair and zygosity were added as random effects to estimate familiality, defined as percentage of variation due to common environment and genetics. IBD-affected twins were used for differences in disease location or treatment. Participants reporting antibiotic/probiotic treatment within the last 3 months or with a stoma/pouch were not included. In UC, surgery-naive patients were compared to an excluded subset who underwent ileostomy or pouch surgery without any recent antibiotic courses.ResultsDisease concordance in MZ twins was higher in CD (54%) than UC (19%). Alpha diversity was lower in CD, but not UC, and in ileostomy and pouch vs. surgery-naive UC. Principal component analysis showed that CD-affected twins clustered apart from non-IBD ones (Figure 1A). Familiality was lower in CD, with 5% of ASVs having familiality > 50%, compared to 17% in UC (Figure 1B). Two Lachnospirales order ASVs were less abundant in UC, while 15 ASVs from Clostridia, Bacteroidia, Bacilli and Coriobacteriia classes differentiated CD from non-IBD. Firmicutes were higher in CD (β= 0.95; 95%CI [0.34,1.56]), while no phyla changed in UC. Veillonella, Barnesiella, Faecalimonas and Holdemania genera had opposite t
Forslund SK, Chakaroun R, Zimmermann-Kogadeeva M, et al., 2021, Combinatorial, additive and dose-dependent drug-microbiome associations, Nature, Vol: 600, Pages: 500-505, ISSN: 0028-0836
During the transition from a healthy state to cardiometabolic disease, patients become heavily medicated, which leads to an increasingly aberrant gut microbiome and serum metabolome, and complicates biomarker discovery1,2,3,4,5. Here, through integrated multi-omics analyses of 2,173 European residents from the MetaCardis cohort, we show that the explanatory power of drugs for the variability in both host and gut microbiome features exceeds that of disease. We quantify inferred effects of single medications, their combinations as well as additive effects, and show that the latter shift the metabolome and microbiome towards a healthier state, exemplified in synergistic reduction in serum atherogenic lipoproteins by statins combined with aspirin, or enrichment of intestinal Roseburia by diuretic agents combined with beta-blockers. Several antibiotics exhibit a quantitative relationship between the number of courses prescribed and progression towards a microbiome state that is associated with the severity of cardiometabolic disease. We also report a relationship between cardiometabolic drug dosage, improvement in clinical markers and microbiome composition, supporting direct drug effects. Taken together, our computational framework and resulting resources enable the disentanglement of the effects of drugs and disease on host and microbiome features in multimedicated individuals. Furthermore, the robust signatures identified using our framework provide new hypotheses for drug–host–microbiome interactions in cardiometabolic disease.
Nalpas N, Hoyles L, Anselm V, et al., 2021, An integrated workflow for enhanced taxonomic and functional coverage of the mouse fecal metaproteome., Gut Microbes, Vol: 13, Pages: 1-23, ISSN: 1949-0976
Intestinal microbiota plays a key role in shaping host homeostasis by regulating metabolism, immune responses and behavior. Its dysregulation has been associated with metabolic, immune and neuropsychiatric disorders and is accompanied by changes in bacterial metabolic regulation. Although proteomics is well suited for analysis of individual microbes, metaproteomics of fecal samples is challenging due to the physical structure of the sample, presence of contaminating host proteins and coexistence of hundreds of taxa. Furthermore, there is a lack of consensus regarding preparation of fecal samples, as well as downstream bioinformatic analyses following metaproteomics data acquisition. Here we assess sample preparation and data analysis strategies applied to mouse feces in a typical mass spectrometry-based metaproteomic experiment. We show that subtle changes in sample preparation protocols may influence interpretation of biological findings. Two-step database search strategies led to significant underestimation of false positive protein identifications. Unipept software provided the highest sensitivity and specificity in taxonomic annotation of the identified peptides of unknown origin. Comparison of matching metaproteome and metagenome data revealed a positive correlation between protein and gene abundances. Notably, nearly all functional categories of detected protein groups were differentially abundant in the metaproteome compared to what would be expected from the metagenome, highlighting the need to perform metaproteomics when studying complex microbiome samples.
Nuzzo A, Guedj K, Curac S, et al., 2021, Accuracy of citrulline, I-FABP and d-lactate in the diagnosis of acute mesenteric ischemia, Scientific Reports, Vol: 11, Pages: 1-10, ISSN: 2045-2322
Early diagnosis of acute mesenteric ischemia (AMI) remains a clinical challenge, and no biomarker has been consistently validated. We aimed to assess the accuracy of three promising circulating biomarkers for diagnosing AMI—citrulline, intestinal fatty acid-binding protein (I-FABP), and D-lactate. A cross-sectional diagnostic study enrolled AMI patients admitted to the intestinal stroke center and controls with acute abdominal pain of another origin. We included 129 patients—50 AMI and 79 controls. Plasma citrulline concentrations were significantly lower in AMI patients compared to the controls [15.3 μmol/L (12.0–26.0) vs. 23.3 μmol/L (18.3–29.8), p = 0.001]. However, the area under the receiver operating curves (AUROC) for the diagnosis of AMI by Citrulline was low: 0.68 (95% confidence interval = 0.58–0.78). No statistical difference was found in plasma I-FABP and plasma D-lactate concentrations between the AMI and control groups, with an AUROC of 0.44, and 0.40, respectively. In this large cross-sectional study, citrulline, I-FABP, and D-lactate failed to differentiate patients with AMI from patients with acute abdominal pain of another origin. Further research should focus on the discovery of new biomarkers.
Bermudez-Martin P, Becker JAJ, Caramello N, et al., 2021, The microbial metabolite p-Cresol induces autistic-like behaviors in mice by remodeling the gut microbiota, Microbiome, Vol: 9, Pages: 1-23, ISSN: 2049-2618
BackgroundAutism spectrum disorders (ASD) are associated with dysregulation of the microbiota-gut-brain axis, changes in microbiota composition as well as in the fecal, serum, and urine levels of microbial metabolites. Yet a causal relationship between dysregulation of the microbiota-gut-brain axis and ASD remains to be demonstrated. Here, we hypothesized that the microbial metabolite p-Cresol, which is more abundant in ASD patients compared to neurotypical individuals, could induce ASD-like behavior in mice.ResultsMice exposed to p-Cresol for 4 weeks in drinking water presented social behavior deficits, stereotypies, and perseverative behaviors, but no changes in anxiety, locomotion, or cognition. Abnormal social behavior induced by p-Cresol was associated with decreased activity of central dopamine neurons involved in the social reward circuit. Further, p-Cresol induced changes in microbiota composition and social behavior deficits could be transferred from p-Cresol-treated mice to control mice by fecal microbiota transplantation (FMT). We also showed that mice transplanted with the microbiota of p-Cresol-treated mice exhibited increased fecal p-Cresol excretion, compared to mice transplanted with the microbiota of control mice. In addition, we identified possible p-Cresol bacterial producers. Lastly, the microbiota of control mice rescued social interactions, dopamine neurons excitability, and fecal p-Cresol levels when transplanted to p-Cresol-treated mice.ConclusionsThe microbial metabolite p-Cresol induces selectively ASD core behavioral symptoms in mice. Social behavior deficits induced by p-Cresol are dependant on changes in microbiota composition. Our study paves the way for therapeutic interventions targeting the microbiota and p-Cresol production to treat patients with ASD.
Martinez-Gili L, Pechlivanis A, Begum S, et al., 2021, Response failure to ursodeoxycholic acid treatment in primary biliary cholangitis is associated with a distinct stool and urine secondary bile acid profile, Publisher: ELSEVIER, Pages: S404-S405, ISSN: 0168-8278
Martinez-Gili L, Mullish BH, Correia G, et al., 2021, A distinctive signature of fecal bile acids and other novel metabolites accompanying recurrence after primary clostridioides difficile infection, Society for Surgery of the Alimentary Tract Annual Meeting at Digestive Disease Week (DDW), Publisher: Elsevier, Pages: S368-S368, ISSN: 0016-5085
Martinez-Gili L, McDonald JAK, Liu Z, et al., 2020, Understanding the mechanisms of efficacy of fecal microbiota transplant in treating recurrent Clostridioides difficile infection and beyond: the contribution of gut microbial derived metabolites, Gut Microbes, Vol: 12, ISSN: 1949-0976
Fecal microbiota transplant (FMT) is a highly-effective therapy for recurrent Clostridioides difficile infection (rCDI), and shows promise for certain non-CDI indications. However, at present, its mechanisms of efficacy have remained poorly understood. Recent studies by our laboratory have noted the particular key importance of restoration of gut microbe-metabolite interactions in the ability of FMT to treat rCDI, including the impact of FMT upon short chain fatty acid (SCFAs) and bile acid metabolism. This includes a significant impact of these metabolites upon the life cycle of C. difficile directly, along with potential postulated additional benefits, including effects upon host immune response. In this Addendum, we first present an overview of these recent advancements in this field, and then describe additional novel data from our laboratory on the impact of FMT for rCDI upon several gut microbial-derived metabolites which had not previously been implicated as being of relevance.
Farràs M, Martinez-Gili L, Portune K, et al., 2020, Modulation of the gut microbiota by olive oil phenolic compounds: implications for lipid metabolism, immune system, and obesity, Nutrients, Vol: 12, Pages: 1-28, ISSN: 2072-6643
There is extensive information of the beneficial effects of virgin olive oil (VOO), especially on cardiovascular diseases. Some VOO healthy properties have been attributed to their phenolic-compounds (PCs). The aim of this review is to present updated data on the effects of olive oil (OO) PCs on the gut microbiota, lipid metabolism, immune system, and obesity, as well as on the crosstalk among them. We summarize experiments and clinical trials which assessed the specific effects of the olive oil phenolic-compounds (OOPCs) without the synergy with OO-fats. Several studies have demonstrated that OOPC consumption increases Bacteroidetes and/or reduces the Firmicutes/Bacteroidetes ratio, which have both been related to atheroprotection. OOPCs also increase certain beneficial bacteria and gut-bacteria diversity which can be therapeutic for lipid-immune disorders and obesity. Furthermore, some of the mechanisms implicated in the crosstalk between OOPCs and these disorders include antimicrobial-activity, cholesterol microbial metabolism, and metabolites produced by bacteria. Specifically, OOPCs modulate short-chain fatty-acids produced by gut-microbiota, which can affect cholesterol metabolism and the immune system, and may play a role in weight gain through promoting satiety. Since data in humans are scarce, there is a necessity for more clinical trials designed to assess the specific role of the OOPCs in this crosstalk.
Martinez-Gili L, McDonald JA, Liu Z, et al., 2020, 644 identification of novel changes in microbially-derived metabolites after fecal microbiota transplant for recurrent clostridioides difficile infection, Publisher: Elsevier BV, Pages: S-138-S-139, ISSN: 0016-5085
Abdul Rahim MBH, Chilloux J, Martinez-Gili L, et al., 2019, Diet-induced metabolic changes of the human gut microbiome: importance of short-chain fatty acids, methylamines and indoles, Acta Diabetologica, Vol: 56, Pages: 493-500, ISSN: 0940-5429
The human gut is a home for more than 100 trillion bacteria, far more than all other microbial populations resident on the body's surface. The human gut microbiome is considered as a microbial organ symbiotically operating within the host. It is a collection of different cell lineages that are capable of communicating with each other and the host and has an ability to undergo self-replication for its repair and maintenance. As the gut microbiota is involved in many host processes including growth and development, an imbalance in its ecological composition may lead to disease and dysfunction in the human. Gut microbial degradation of nutrients produces bioactive metabolites that bind target receptors, activating signalling cascades, and modulating host metabolism. This review covers current findings on the nutritional and pharmacological roles of selective gut microbial metabolites, short-chain fatty acids, methylamines and indoles, as well as discussing nutritional interventions to modulate the microbiome.
Leboucher A, Pisani DF, Martinez-Gili L, et al., 2019, The translational regulator FMRP controls lipid and glucose metabolism in mice and humans, Molecular Metabolism, Vol: 21, Pages: 22-35, ISSN: 2212-8778
ObjectivesThe Fragile X Mental Retardation Protein (FMRP) is a widely expressed RNA-binding protein involved in translation regulation. Since the absence of FMRP leads to Fragile X Syndrome (FXS) and autism, FMRP has been extensively studied in brain. The functions of FMRP in peripheral organs and on metabolic homeostasis remain elusive; therefore, we sought to investigate the systemic consequences of its absence.MethodsUsing metabolomics, in vivo metabolic phenotyping of the Fmr1-KO FXS mouse model and in vitro approaches, we show that the absence of FMRP induced a metabolic shift towards enhanced glucose tolerance and insulin sensitivity, reduced adiposity, and increased β-adrenergic-driven lipolysis and lipid utilization.ResultsCombining proteomics and cellular assays, we highlight that FMRP loss increased hepatic protein synthesis and impacted pathways notably linked to lipid metabolism. Mapping metabolomic and proteomic phenotypes onto a signaling and metabolic network, we predicted that the coordinated metabolic response to FMRP loss was mediated by dysregulation in the abundances of specific hepatic proteins. We experimentally validated these predictions, demonstrating that the translational regulator FMRP associates with a subset of mRNAs involved in lipid metabolism. Finally, we highlight that FXS patients mirror metabolic variations observed in Fmr1-KO mice with reduced circulating glucose and insulin and increased free fatty acids.ConclusionsLoss of FMRP results in a widespread coordinated systemic response that notably involves upregulation of protein translation in the liver, increased utilization of lipids, and significant changes in metabolic homeostasis. Our study unravels metabolic phenotypes in FXS and further supports the importance of translational regulation in the homeostatic control of systemic metabolism.
Hoyles L, Fernández-Real JM, Federici M, et al., 2018, Molecular phenomics and metagenomics of hepatic steatosis in non-diabetic obese women, Nature Medicine, Vol: 24, Pages: 1-17, ISSN: 1078-8956
Hepatic steatosis is a multifactorial condition that is often observed in obese patients and is a prelude to non-alcoholic fatty liver disease. Here, we combine shotgun sequencing of fecal metagenomes with molecular phenomics (hepatic transcriptome and plasma and urine metabolomes) in two well-characterized cohorts of morbidly obese women recruited to the FLORINASH study. We reveal molecular networks linking the gut microbiome and the host phenome to hepatic steatosis. Patients with steatosis have low microbial gene richness and increased genetic potential for the processing of dietary lipids and endotoxin biosynthesis (notably from Proteobacteria), hepatic inflammation and dysregulation of aromatic and branched-chain amino acid metabolism. We demonstrated that fecal microbiota transplants and chronic treatment with phenylacetic acid, a microbial product of aromatic amino acid metabolism, successfully trigger steatosis and branched-chain amino acid metabolism. Molecular phenomic signatures were predictive (area under the curve = 87%) and consistent with the gut microbiome having an effect on the steatosis phenome (>75% shared variation) and, therefore, actionable via microbiome-based therapies.
Baulies A, Montero J, Matías N, et al., 2017, The 2-oxoglutarate carrier promotes liver cancer by sustaining mitochondrial GSH despite cholesterol loading., Redox Biology, Vol: 14, Pages: 164-177, ISSN: 2213-2317
Cancer cells exhibit mitochondrial cholesterol (mt-cholesterol) accumulation, which contributes to cell death resistance by antagonizing mitochondrial outer membrane (MOM) permeabilization. Hepatocellular mt-cholesterol loading, however, promotes steatohepatitis, an advanced stage of chronic liver disease that precedes hepatocellular carcinoma (HCC), by depleting mitochondrial GSH (mGSH) due to a cholesterol-mediated impairment in mGSH transport. Whether and how HCC cells overcome the restriction of mGSH transport imposed by mt-cholesterol loading to support mGSH uptake remains unknown. Although the transport of mGSH is not fully understood, SLC25A10 (dicarboxylate carrier, DIC) and SLC25A11 (2-oxoglutarate carrier, OGC) have been involved in mGSH transport, and therefore we examined their expression and role in HCC. Unexpectedly, HCC cells and liver explants from patients with HCC exhibit divergent expression of these mitochondrial carriers, with selective OGC upregulation, which contributes to mGSH maintenance. OGC but not DIC downregulation by siRNA depleted mGSH levels and sensitized HCC cells to hypoxia-induced ROS generation and cell death as well as impaired cell growth in three-dimensional multicellular HCC spheroids, effects that were reversible upon mGSH replenishment by GSH ethyl ester, a membrane permeable GSH precursor. We also show that OGC regulates mitochondrial respiration and glycolysis. Moreover, OGC silencing promoted hypoxia-induced cardiolipin peroxidation, which reversed the inhibition of cholesterol on the permeabilization of MOM-like liposomes induced by Bax or Bak. Genetic OGC knockdown reduced the ability of tumor-initiating stem-like cells to induce liver cancer. These findings underscore the selective overexpression of OGC as an adaptive mechanism of HCC to provide adequate mGSH levels in the face of mt-cholesterol loading and suggest that OGC may be a novel therapeutic target for HCC treatment.
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