A mechanism by which gut microbiota elevates permeability and inflammation in obese/diabetic mice and human gut.

OBJECTIVE: Ample evidence exists for the role of abnormal gut microbiota composition and increased gut permeability ('leaky gut') in chronic inflammation that commonly co-occurs in the gut in both obesity and diabetes, yet the detailed mechanisms involved in this process have remained elusive. DESIGN: In this study, we substantiate the causal role of the gut microbiota by use of faecal conditioned media along with faecal microbiota transplantation. Using untargeted and comprehensive approaches, we discovered the mechanism by which the obese microbiota instigates gut permeability, inflammation and abnormalities in glucose metabolism. RESULTS: We demonstrated that the reduced capacity of the microbiota from both obese mice and humans to metabolise ethanolamine results in ethanolamine accumulation in the gut, accounting for induction of intestinal permeability. Elevated ethanolamine increased the expression of microRNA-miR-101a-3p by enhancing ARID3a binding on the miR promoter. Increased miR-101a-3p decreased the stability of zona occludens-1 (Zo1) mRNA, which in turn, weakened intestinal barriers and induced gut permeability, inflammation and abnormalities in glucose metabolism. Importantly, restoring ethanolamine-metabolising activity in gut microbiota using a novel probiotic therapy reduced elevated gut permeability, inflammation and abnormalities in glucose metabolism by correcting the ARID3a/miR-101a/Zo1 axis. CONCLUSION: Overall, we discovered that the reduced capacity of obese microbiota to metabolise ethanolamine instigates gut permeability, inflammation and glucose metabolic dysfunctions, and restoring ethanolamine-metabolising capacity by a novel probiotic therapy reverses these abnormalities. TRIAL REGISTRATION NUMBER: NCT02869659 and NCT03269032.

Abnormalities in microbiota/butyrate/FFAR3 signaling in aging gut impair brain function.

Aging-related abnormalities in gut microbiota are associated with cognitive decline, depression, and anxiety, but underlying mechanisms remain unstudied. Here, our study demonstrated that transplanting old gut microbiota to young mice induced inflammation in the gut and brain coupled with cognitive decline, depression, and anxiety. We observed diminished mucin formation and increased gut permeability ("leaky gut") with a reduction in beneficial metabolites like butyrate because of decline in butyrate-producing bacteria in the aged gut microbiota. This led to suppressed expression of butyrate receptors, free fatty acid receptors 2 and 3 (FFAR2/3). Administering butyrate alleviated inflammation, restored mucin expression and gut barriers, and corrected brain dysfunction. Furthermore, young mice with intestine-specific loss of FFAR2/3 exhibited gut and brain abnormalities akin to those in older mice. Our results demonstrate that reduced butyrate-producing bacteria in aged gut microbiota result in low butyrate levels and reduced FFAR2/3 signaling, leading to suppressed mucin formation that increases gut permeability, inflammation, and brain abnormalities. These findings underscore the significance of butyrate-FFAR2/3 agonism as a potential strategy to mitigate aged gut microbiota-induced detrimental effects on gut and brain health in older adults.

New Horizons in Microbiota and Metabolic Health Research.

Decade-old studies have demonstrated that microbes living in our gut (microbiota) contribute to both maintaining normal metabolic function and to the pathology of metabolic diseases, such as obesity and diabetes. Emerging evidence suggests that gut microbiota influences the personalized effects of diets and drugs and impact the gut-brain axis and leaky gut inflammation to control metabolic function/diseases. Gut microbiota can be an ideal source of prognostic markers and therapies for metabolic diseases. Here we discuss the emerging concepts in the area of microbiota and metabolic interactions in personalized nutrition, drug response, and disease prognosis.

Free Fatty Acid Receptors 2 and 3 as Microbial Metabolite Sensors to Shape Host Health: Pharmacophysiological View.

The role of the gut microbiome in human health is becoming apparent. The major functional impact of the gut microbiome is transmitted through the microbial metabolites that are produced in the gut and interact with host cells either in the local gut environment or are absorbed into circulation to impact distant cells/organs. Short-chain fatty acids (SCFAs) are the major microbial metabolites that are produced in the gut through the fermentation of non-digestible fibers. SCFAs are known to function through various mechanisms, however, their signaling through free fatty acid receptors 2 and 3 (FFAR2/3; type of G-coupled protein receptors) is a new therapeutic approach. FFAR2/3 are widely expressed in diverse cell types in human and mice, and function as sensors of SCFAs to change several physiological and cellular functions. FFAR2/3 modulate neurological signaling, energy metabolism, intestinal cellular homeostasis, immune response, and hormone synthesis. FFAR2/3 function through Gi and/or Gq signaling, that is mediated through specific structural features of SCFAs-FFAR2/3 bindings and modulating specific signaling pathway. In this review, we discuss the wide-spread expression and structural homologies between human and mice FFAR2/3, and their role in different human health conditions. This information can unlock opportunities to weigh the potential of FFAR2/3 as a drug target to prevent human diseases.

Investigating genetic variability in Hsp70 gene-5'-fragment and its association with thermotolerance in Murrah buffalo (Bubalus bubalis) under sub-tropical climate of India.

The present study was undertaken to investigate genetic variability in a fragment comprising 5'UTR along with partial coding sequence of Hsp70 gene and its association with thermotolerance traits in Murrah buffalo at ICAR-Research Complex for Eastern Region, Patna (India). The allelic variants were identified from genomic DNA samples using SSCP technique. The PCR products were sequenced and analyzed. Data on different thermotolerance traits recorded in three seasons were analyzed by least squares ANOVA taking the SSCP genotypes as fixed effect. Two allelic variants (A and B), each of 503-bp in size, were documented with frequency of 0.59 and 0.41, respectively, and three genotypes (AA, AB and BB) with corresponding frequency of 0.30, 0.58 and 0.12. The allelic variants were due to single nucleotide substitution at 55th base position leading to a change of threonine (A) to methionine (B) in amino acid sequence. Both the allelic variants had 99.8% similarity in nucleotide sequence. In phylogenetic tree, allele A was in a cluster while allele B and Gangatiri cattle sequence formed a different cluster. The SSCP genotypes had significant effect on different thermotolerance traits in summer with thermo-humidity index of ≥ 84. Buffaloes with AA genotype had the highest (P Ë‚ 0.05) summer evening rectal temperature, respiration rate and pulse rate, inferring that the buffaloes carrying AA genotype had more stress in summer than those with AB and BB genotype. These SSCP genotypes might have differential role in heat shock protein response to induce thermotolerance of Murrah buffaloes in Gangetic plains.

Probiotics and Prebiotics for the Amelioration of Type 1 Diabetes: Present and Future Perspectives.

Type 1-diabetes (T1D) is an autoimmune disease characterized by immune-mediated destruction of pancreatic beta (ß)-cells. Genetic and environmental interactions play an important role in immune system malfunction by priming an aggressive adaptive immune response against ß-cells. The microbes inhabiting the human intestine closely interact with the enteric mucosal immune system. Gut microbiota colonization and immune system maturation occur in parallel during early years of life; hence, perturbations in the gut microbiota can impair the functions of immune cells and vice-versa. Abnormal gut microbiota perturbations (dysbiosis) are often detected in T1D subjects, particularly those diagnosed as multiple-autoantibody-positive as a result of an aggressive and adverse immunoresponse. The pathogenesis of T1D involves activation of self-reactive T-cells, resulting in the destruction of ß-cells by CD8⁺ T-lymphocytes. It is also becoming clear that gut microbes interact closely with T-cells. The amelioration of gut dysbiosis using specific probiotics and prebiotics has been found to be associated with decline in the autoimmune response (with diminished inflammation) and gut integrity (through increased expression of tight-junction proteins in the intestinal epithelium). This review discusses the potential interactions between gut microbiota and immune mechanisms that are involved in the progression of T1D and contemplates the potential effects and prospects of gut microbiota modulators, including probiotic and prebiotic interventions, in the amelioration of T1D pathology, in both human and animal models.

Genetic profiling of Hsp70 gene in Murrah buffalo (Bubalus bubalis) under sub-tropical climate of India.

This study was aimed to genetic profiling of heat shock protein 70 (Hsp70) gene in Murrah buffalo investigating 50 unrelated adult animals at ICAR-Research Complex for Eastern Region, Patna (India) in winter, spring, and summer. PCR ready genomic DNA samples and season-wise total RNA samples were prepared. The PCR products of Hsp70 eluted from agarose gel were sequenced and analyzed. The first-strand cDNA was synthesized and concentration was equalized to 25 ng/µl. Expression kinetics of mRNA transcripts in different seasons was studied using Brilliant SYBR Green QPCR technique and the data retrieved was analyzed by least-squares ANOVA. DNA sequencing by primer walking revealed four allelic variants of Hsp70 gene. Alignment study revealed one substitution in 5'UTR, six substitutions in coding region, and one addition in 3'UTR. The highest percent identity and negligible phylogenetic distance were found among the alleles and reference bovine sequences. The relative mRNA expression was significantly higher in summer when THI ≥ 84 than the spring and winter; fold change increased by 4.5 times in summer than the spring whereas found nearly half in winter. These findings can be useful for heat stress management in buffaloes and help in understanding the mechanism of thermo-regulation well.

Investigation of transferrin polymorphism in Garole sheep.

The aim of this study was to determine the genetics of polymorph systems of Transferrin in Garole sheep breed. The present study was conducted on 95 adult Garole sheep comprising 52 ewes and 43 rams, maintained at Sheep and Goat Breeding Farm of West Bengal University of Animal and Fishery Sciences, West Bengal, during the period from April-September, 2009. The polymorphism of transferrin was determined through SDS-Polyacrylamide gel electrophoresis technique. It was found that the transferrin type was controlled by five codominant alleles (TfA, TfB, TfC TfD and TfE) in Garole sheep. These five alleles, because of co-dominant nature of inheritance, determined the occurrence of nine transferrin genotypes in the analyzed flock. Four (TfAA, TfBB, TfCC and TfDD) of these were homozygous and the remaining five (TfAD, TfBC, TfBD, TfCD and TfDE) heterozygous. It was found that the TfDD genotype (0.263) was predominant while TfDE genotype (0.042) was least common in the analyzed flock. Frequencies of other genotypes were as: TfCD(0.242), TfBD(0.126), TfCC(0.084), TfBB(0.074), TfAA(0.063), TfAD and TfBC (0.053 for each genotype ) in whole population. From the result it was found that in whole population combined, the heterozygotic genotypic frequency (0.516) was more than that of homozygotic genotypic frequency (0.484). Considerable variations were recognized in the frequencies of transferrin alleles. In the whole population frequencies of transferrin alleles were found to be TfA = 0.089, TfB = 0.163, TfC = 0.232, TfD = 0.495 and TfE = 0.021. Transferrin system has shown an absence of genetic equilibrium among the analyzed herd (chi2 value = 51.31). In conclusion, there were polymorphism in Transferrin types and the presence of differences among the frequencies of the five alleles by categories could be a source of genetic variation in Garole sheep.