Gut microbiota dysbiosis in a cohort of patients with psoriasis.

BACKGROUND: There is increasing evidence of the key role that the gut microbiota plays in inflammatory diseases. OBJECTIVES: To identify differences in the faecal microbial composition of patients with psoriasis compared with healthy individuals in order to unravel the microbiota profiling in this autoimmune disease. METHODS: 16S rRNA gene sequencing and bioinformatic analyses were performed with the total DNA extracted from the faecal microbiota of 19 patients with psoriasis and 20 healthy individuals from the same geographic location. RESULTS: Gut microbiota composition of patients with psoriasis displayed a lower diversity and different relative abundance of certain bacterial taxa compared with healthy individuals. CONCLUSIONS: The gut microbiota profile of patients with psoriasis displayed a clear dysbiosis that can be targeted for microbiome-based therapeutic approaches. What's already known about this topic? Psoriasis is a chronic inflammatory immune-mediated skin disease, the aetiology of which remains unclear. The human microbiota is a complex microbial community that inhabits our body and has been related with the maintenance of a healthy status. Several studies have focused on the skin microbiome and its connection with psoriasis although less attention has been focused on the potential role of the gut microbiota in psoriatic disease. What does this study add? This study unravels the gut microbiome dysbiosis present in a cohort of patients with psoriasis, compared with a healthy control group from the same geographical location. This study shows a lower bacterial diversity and different relative abundance of certain bacterial taxa in patients with psoriasis. We gain knowledge and insight into the microbiome alterations in psoriatic disease, opening new avenues for therapeutic approaches to reshape the human microbiome towards a healthy status.

Extraction of the same novel homoglycan mixture from two different strains of Bifidobacterium animalis and three strains of Bifidobacterium breve.

Three strains of Bifidobacterium breve (JCM 7017, JCM 7019 and JCM 2258) and two strains of Bifidobacterium animalis subsp. lactis (AD011 and A1dOxR) were grown in broth cultures or on plates, and a standard exopolysaccharide extraction method was used in an attempt to recover exocellular polysaccharides. When the extracted materials were analysed by NMR it was clear that mixtures of polysaccharides were being isolated including exopolysaccharides (EPS) cell wall polysaccharides and intracellular polysaccharides. Treatment of the cell biomass from the B. breve strains, or the B. animalis subsp. lactis AD011 strain, with aqueous sodium hydroxide provided a very similar mixture of polysaccharides but without the EPS. The different polysaccharides were partially fractionated by selective precipitation from an aqueous solution upon the addition of increasing percentages of ethanol. The polysaccharides extracted from B. breve JCM 7017 grown in HBM media supplemented with glucose (or isotopically labelled D-glucose-1-13C) were characterised using 1D and 2D-NMR spectroscopy. Addition of one volume of ethanol generated a medium molecular weight glycogen (Mw=1×105 Da, yield 200 mg/l). The addition of two volumes of ethanol precipitated an intimate mixture of a low molecular weight ß-(1→6)-glucan and a low molecular weight ß-(1→6)-galactofuranan which could not be separated (combined yield 46 mg/l). When labelled D-glucose-1-13C was used as a carbon supplement, the label was incorporated into >95% of the anomeric carbons of each polysaccharide confirming they were being synthesised in situ. Similar 1H NMR profiles were obtained for polysaccharides recovered from the cells of B. animalis subsp. lactis AD011and A1dOxR (in combination with an EPS), B. breve JCM 7017, B. breve JCM 7019, B. breve JCM 2258 and from an EPS (-ve) mutant of B. breve 7017 (a non-EPS producer).

Degenerate PCR primers for detecting putative priming glycosyltransferase genes in Bifidobacterium strains.

A new PCR-based method to detect putative exopolysaccharide (EPS) producers from the genus Bifidobacterium was developed based on the detection of two priming glycosyltransferase genes: rfbP (undecaprenyl-phosphate sugar phospho-transferase) and cpsD (galactosyl-transferase). An in silico analysis of the genomes of 28 bifidobacterial strains, belonging to 8 different species, allowed us to detect rfbP, cpsD, or both, in the large majority of the genomes. Based on DNA sequence homology studies, 24 degenerated primers were synthesised in order to select the primer pairs with the broadest capacity to detect the presence of these genes. Four primer pairs targeting internal regions of rfbP and cpsD were selected, allowing the detection of at least one of the two genes in 63 out of 99 bifidobacterial strains analysed, whereas control strains from other genera yielded negative results, suggesting that these genes are widely spread in this genus. The use of these primers is recommended to screen for the potential of Bifidobacterium strains to produce EPS.