The gut microbiome has been implicated in multiple human chronic gastrointestinal (GI) disorders. Determining its mechanistic role in disease has been difficult due to apparent disconnects between ...animal and human studies and lack of an integrated multi-omics view of disease-specific physiological changes. We integrated longitudinal multi-omics data from the gut microbiome, metabolome, host epigenome, and transcriptome in the context of irritable bowel syndrome (IBS) host physiology. We identified IBS subtype-specific and symptom-related variation in microbial composition and function. A subset of identified changes in microbial metabolites correspond to host physiological mechanisms that are relevant to IBS. By integrating multiple data layers, we identified purine metabolism as a novel host-microbial metabolic pathway in IBS with translational potential. Our study highlights the importance of longitudinal sampling and integrating complementary multi-omics data to identify functional mechanisms that can serve as therapeutic targets in a comprehensive treatment strategy for chronic GI diseases.
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•Longitudinal sampling limits heterogeneity seen in cross-sectional microbiome studies•Alteration in the gut microbiome and microbial metabolites underlie IBS and symptom flares•Data integration reveals effect of microbial metabolites on gastrointestinal function•Purine starvation is identified as a possible therapeutic target in IBS
Integrated and longitudinal multiomic analyses of patients with irritable bowel syndrome reveals a role for the gut microbiota in modulating purine metabolism and influencing host gastrointestinal function.
ABSTRACTThe Ca2+‐activated Cl− channel, anoctamin 1 (Ano1, also known as transmembrane protein 16A) contributes to intestinal pacemaking, fluid secretion, cellular excitability, and tissue ...development. The human ANO1 promoter contains binding sites for the glioma‐associated oncogene (Gli) proteins. We investigated regulation of ANO1 transcription by Gli. ANO1 promoter activity was determined using a luciferase reporter system. Binding and functional effects of Glis on ANO1 transcription and expression were demonstrated by chromatin immunoprecipitation, small interfering RNA knockdown, PCR, immunolabeling, and recordings of Ca2+‐activated Cl− currents in human embryonic kidney 293 (HEK293) cells. Results from previous genome‐wide association studies were used to test ANO1 promoter polymorphisms for association with disease. Gli1 and Gli2 bound to the promoter and repressed ANO1 transcription. Repression depended on Gli binding to a site close to the ANO1 transcriptional start site. Mutation of this site prevented Gli binding and transcriptional repression. Knockdown of Gli expression and inhibition of Gli activity increased expression of ANO1 RNA and Ca2+‐activated Cl− currents in HEK293 cells. A single‐nucleotide polymorphism prevented Gli binding and showed association with irritable bowel syndrome. We conclude that Gli1 and Gli2 repress ANO1 by a novel mechanism that is independent of Gli cleavage and that has a role in gastrointestinal function.—Mazzone, A., Gibbons, S. J., Eisenman, S. T., Strege, P. R., Zheng, T., D'Amato, M., Ordog, T., Fernandez‐Zapico, M. E., Farrugia, G. Direct repression of anoctamin 1 (ANO1) gene transcription by Gli proteins. FASEB J. 33, 6632–6642 (2019). www.fasebj.org
Aim
This study aimed to investigate the presence of plasma minichromosome maintenance complex component 6 (MCM6) mRNA and protein levels in hepatocellular carcinoma (HCC) patients and evaluate their ...diagnostic value for HCC.
Methods
Blood samples were collected from 61 HCC and 29 cirrhotic patients, and 30 healthy individuals. Circulating RNA was extracted from plasma of all samples. The mRNA for MCM6 were amplified and quantified by real‐time polymerase chain reaction. Plasma MCM6 and α‐fetoprotein (AFP) protein levels were measured by enzyme‐linked immunosorbent assay.
Results
In HCC patients, MCM6 mRNA and protein levels were significantly increased over the cirrhotic and healthy controls. The levels of MCM6 mRNA and protein in the plasma of HCC patients correlated to vascular invasion (P < 0.01). Higher MCM6 protein levels also correlated with tumor stage progression and lymph node metastasis. The MCM6 protein has sensitivity of 67.2% and specificity of 89.8% in differentiating total HCC from non‐HCC individuals. In the AFP negative HCC group, MCM6 mRNA and protein could both detect 76.9% of HCC patients; combining the two of them increased the detection rate to 84.6%. In small HCC patients, MCM6 mRNA and protein could detect 64.3% and 71.4% of patients, respectively; combining AFP, MCM6 mRNA and MCM6 protein could detect 85.7% of small HCC patients.
Conclusion
Our results suggest that MCM6 mRNA and protein levels in plasma can be promising independent biomarkers for HCC, especially in AFP negative and small HCC patients.
Fluconazole, a commonly used azole antifungal drug, can induce QT prolongation, which may lead to Torsades de Pointes and sudden death. To investigate the arrhythmogenic side effects of fluconazole, ...we studied the effect of fluconazole on human
ether-
a-
go-
go-related gene (hERG) K
+ channels (wild type, Y652A and F656C) expressed in human embryonic kidney (HEK293) cells using a whole-cell patch clamp technique, Western blot analysis and confocal microscopy. Fluconazole inhibited wild type hERG currents in a concentration-dependent manner, with a half-maximum block concentration (IC
50) of 48.2
±
9.4
μM. Fluconazole did not change other channel kinetics (activation and steady-state inactivation) of hERG channel. Mutations in drug- binding sites (Y652A or F656C) of the hERG channel significantly attenuated the hERG current blockade by fluconazole. In addition, fluconazole inhibited the trafficking of hERG protein by Western blot analysis and confocal microscopy, respectively. These findings indicate that fluconazole may cause acquired long QT syndrome (LQTS) via a direct inhibition of hERG current and by disrupting hERG protein trafficking, and the mutations Y652 and F656 may be obligatory determinants in inhibition of hERG current for fluconazole.
Gut dysmotility is associated with constipation, diarrhea, and functional gastrointestinal disorders like irritable bowel syndrome (IBS), although its molecular underpinnings are poorly ...characterized. We studied stool frequency (defined by the number of bowel movements per day, based on questionnaire data) as a proxy for gut motility in a GWAS meta-analysis including 167,875 individuals from UK Biobank and four smaller population-based cohorts. We identify 14 loci associated with stool frequency (p ≤ 5.0 × 10−8). Gene set and pathway analyses detected enrichment for genes involved in neurotransmitter/neuropeptide signaling and preferentially expressed in enteric motor neurons controlling peristalsis. PheWAS identified pleiotropic associations with dysmotility syndromes and the response to their pharmacological treatment. The genetic architecture of stool frequency correlates with that of IBS, and UK Biobank participants from the top 1% of stool frequency polygenic score distribution were associated with 5× higher risk of IBS with diarrhea. These findings pave the way for the identification of actionable pathological mechanisms in IBS and the dysmotility syndromes.
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Genetics of gut motility via data on stool frequency in 167,875 individualsGWAS identifies 14 loci associated with stool frequencyCandidate genes enriched in neurotransmitter signaling and enteric motor neuronsPolygenic scores predict increased risk of irritable bowel syndrome
Bonfiglio et al. investigate the genetics of human gut motility using genotype and questionnaire data on stool frequency in 167,875 individuals from the UK Biobank and four other cohorts. They identify 14 loci associated with stool frequency as well as candidate genes enriched in neurotransmitter signaling and preferentially expressed in enteric neurons controlling peristalsis. The genetic architecture of stool frequency correlates with that of irritable bowel syndrome (IBS), and stool frequency polygenic scores were predictive of IBS risk.
The gut microbiome and hypertension O'Donnell, Joanne A; Zheng, Tenghao; Meric, Guillaume ...
Nature reviews. Nephrology,
03/2023, Letnik:
19, Številka:
3
Journal Article
Recenzirano
A large body of evidence has emerged in the past decade supporting a role for the gut microbiome in the regulation of blood pressure. The field has moved from association to causation in the last 5 ...years, with studies that have used germ-free animals, antibiotic treatments and direct supplementation with microbial metabolites. The gut microbiome can regulate blood pressure through several mechanisms, including through gut dysbiosis-induced changes in microbiome-associated gene pathways in the host. Microbiota-derived metabolites are either beneficial (for example, short-chain fatty acids and indole-3-lactic acid) or detrimental (for example, trimethylamine N-oxide), and can activate several downstream signalling pathways via G protein-coupled receptors or through direct immune cell activation. Moreover, dysbiosis-associated breakdown of the gut epithelial barrier can elicit systemic inflammation and disrupt intestinal mechanotransduction. These alterations activate mechanisms that are traditionally associated with blood pressure regulation, such as the renin-angiotensin-aldosterone system, the autonomic nervous system, and the immune system. Several methodological and technological challenges remain in gut microbiome research, and the solutions involve minimizing confounding factors, establishing causality and acting globally to improve sample diversity. New clinical trials, precision microbiome medicine and computational methods such as Mendelian randomization have the potential to enable leveraging of the microbiome for translational applications to lower blood pressure.
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