Crohn’s disease (CD)–associated variants in the LRRK2 gene for risk (N2081D) and for protection (N551K) mediate shared effects in CD and Parkinson’s disease.
In eukaryotes, a key step in the initiation of translation is the binding of the eukaryotic initiation factor 4E (eIF4E) to the cap structure of the mRNA. Subsequent recruitment of several components, including the small ribosomal subunit, is thought to allow migration of initiation complexes and recognition of the initiation codon. Mitogens and cytokines stimulate the phosphorylation of eIF4E at Ser209, but the functional consequences of this modification have remained a major unresolved question. Using fluorescence spectroscopy and surface plasmon resonance techniques, we show that phosphorylation of eIF4E markedly reduces its affinity for capped RNA, primarily due to an increased rate of dissociation. Variant eIF4E proteins harboring negatively charged acidic residues at position 209 also showed decreased binding to capped RNA. Furthermore, a basic residue at position 159 was shown to be essential for cap binding. Although eIF4E-binding protein 1 greatly stabilized binding of phosphorylated eIF4E to capped RNA, in the presence of eIF4E-binding protein 1 the phosphorylated form still dissociated faster compared with nonphopshorylated eIF4E. The implications of our findings for the mechanism of translation initiation are discussed.
This study was aimed to assess the diversity of the meconium microbiome and determine if the bacterial community is affected by maternal diabetes status. The first intestinal discharge (meconium) was collected from 23 newborns stratified by maternal diabetes status: 4 mothers had pre-gestational type 2 diabetes mellitus (DM) including one mother with dizygotic twins, 5 developed gestational diabetes mellitus (GDM) and 13 had no diabetes. The meconium microbiome was profiled using multi-barcode 16S rRNA sequencing followed by taxonomic assignment and diversity analysis. All meconium samples were not sterile and contained diversified microbiota. Compared with adult feces, the meconium showed a lower species diversity, higher sample-to-sample variation, and enrichment of Proteobacteria and reduction of Bacteroidetes. Among the meconium samples, the taxonomy analyses suggested that the overall bacterial content significantly differed by maternal diabetes status, with the microbiome of the DM group showing higher alpha-diversity than that of no-diabetes or GDM groups. No global difference was found between babies delivered vaginally versus via Cesarean-section. Regression analysis showed that the most robust predictor for the meconium microbiota composition was the maternal diabetes status that preceded pregnancy. Specifically, Bacteroidetes (phyla) and Parabacteriodes (genus) were enriched in the meconium in the DM group compared to the no-diabetes group. Our study provides evidence that meconium contains diversified microbiota and is not affected by the mode of delivery. It also suggests that the meconium microbiome of infants born to mothers with DM is enriched for the same bacterial taxa as those reported in the fecal microbiome of adult DM patients.
9 February 2016 in Alimentary Pharmacology & Therapeutics
Summary: Background: Little is known about the role of the microbiome in primary sclerosing cholangitis.Aim: To explore the mucosa‐associated microbiota in primary sclerosing cholangitis (PSC) patients across different locations in the gut, and to compare it with inflammatory bowel disease (IBD)‐only patients and healthy controls.Methods: Biopsies from the terminal ileum, right colon, and left colon were collected from patients and healthy controls undergoing colonoscopy. Microbiota profiling using bacterial 16S rRNA sequencing was performed on all biopsies.Results: Forty‐four patients were recruited: 20 with PSC (19 with PSC‐IBD and one with PSC‐only), 15 with IBD‐only and nine healthy controls. The overall microbiome profile was similar throughout different locations in the gut. No differences in the global microbiome profile were found. However, we observed significant PSC‐associated enrichment in Barnesiellaceae at the family level, and in Blautia and an unidentified Barnesiellaceae at the genus level. At the operational taxa unit level, most shifts in PSC were observed in Clostridiales and Bacteroidales orders, with approximately 86% of shifts occurring within the former order.Conclusions: The overall microbiota profile was similar across multiple locations in the gut from the same individual regardless of disease status. In this study, the mucosa associated‐microbiota of patients with primary sclerosing cholangitis was characterised by enrichment of Blautia and Barnesiellaceae and by major shifts in operational taxa units within Clostridiales order.