32 research outputs found

    Stable Engraftment of \u3ci\u3eBifidobacterium longum\u3c/i\u3e AH1206 in the Human Gut Depends on Individualized Features of the Resident Microbiome

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    Live bacteria (such as probiotics) have long been used to modulate gut microbiota and human physiology, but their colonization is mostly transient. Conceptual understanding of the ecological principles as they apply to exogenously introduced microbes in gut ecosystems is lacking. We find that, when orally administered to humans, Bifidobacterium longum AH1206 stably persists in the gut of 30% of individuals for at least 6 months without causing gastrointestinal symptoms or impacting the composition of the resident gut microbiota. AH1206 engraftment was associated with low abundance of resident B. longum and underrepresentation of specific carbohydrate utilization genes in the pre-treatment microbiome. Thus, phylogenetic limiting and resource availability are two factors that control the niche opportunity for AH1206 colonization. These findings suggest that bacterial species and functional genes absent in the gut microbiome of individual humans can be reestablished, providing opportunities for precise and personalized microbiome reconstitution

    Stable Engraftment of \u3ci\u3eBifidobacterium longum\u3c/i\u3e AH1206 in the Human Gut Depends on Individualized Features of the Resident Microbiome

    Get PDF
    Live bacteria (such as probiotics) have long been used to modulate gut microbiota and human physiology, but their colonization is mostly transient. Conceptual understanding of the ecological principles as they apply to exogenously introduced microbes in gut ecosystems is lacking. We find that, when orally administered to humans, Bifidobacterium longum AH1206 stably persists in the gut of 30% of individuals for at least 6 months without causing gastrointestinal symptoms or impacting the composition of the resident gut microbiota. AH1206 engraftment was associated with low abundance of resident B. longum and underrepresentation of specific carbohydrate utilization genes in the pre-treatment microbiome. Thus, phylogenetic limiting and resource availability are two factors that control the niche opportunity for AH1206 colonization. These findings suggest that bacterial species and functional genes absent in the gut microbiome of individual humans can be reestablished, providing opportunities for precise and personalized microbiome reconstitution

    Molecular and functional correction of a deep intronic splicing mutation in CFTR by CRISPR-Cas9 gene editing

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    Cystic fibrosis (CF) is an autosomal recessive disorder caused by mutations in the CFTR gene. The 10th most common mutation, c.3178-2477C>T (3849+10kb C>T), involves a cryptic, intronic splice site. This mutation was corrected in CF primary cells homozygous for this mutation by delivering pairs of guide RNAs (gRNAs) with Cas9 protein in ribonucleoprotein (RNP) complexes that introduce double-strand breaks to flanking sites to excise the 3849+10kb C>T mutation, followed by DNA repair by the non-homologous end-joining pathway, which functions in all cells of the airway epithelium. RNP complexes were delivered to CF basal epithelial cell by a non-viral, receptor-targeted nanocomplex comprising a formulation of targeting peptides and lipids. Canonical CFTR mRNA splicing was, thus, restored leading to the restoration of CFTR protein expression with concomitant restoration of electrophysiological function in airway epithelial air-liquid interface cultures. Off-target editing was not detected by Sanger sequencing of in silico-selected genomic sites with the highest sequence similarities to the gRNAs, although more sensitive unbiased whole genome sequencing methods would be required for possible translational developments. This approach could potentially be used to correct aberrant splicing signals in several other CF mutations and other genetic disorders where deep-intronic mutations are pathogenic

    Interaction Testing and Polygenic Risk Scoring to Estimate the Association of Common Genetic Variants with Treatment Resistance in Schizophrenia

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    Importance: About 20% to 30% of people with schizophrenia have psychotic symptoms that do not respond adequately to first-line antipsychotic treatment. This clinical presentation, chronic and highly disabling, is known as treatment-resistant schizophrenia (TRS). The causes of treatment resistance and their relationships with causes underlying schizophrenia are largely unknown. Adequately powered genetic studies of TRS are scarce because of the difficulty in collecting data from well-characterized TRS cohorts. Objective: To examine the genetic architecture of TRS through the reassessment of genetic data from schizophrenia studies and its validation in carefully ascertained clinical samples. Design, Setting, and Participants: Two case-control genome-wide association studies (GWASs) of schizophrenia were performed in which the case samples were defined as individuals with TRS (n = 10501) and individuals with non-TRS (n = 20325). The differences in effect sizes for allelic associations were then determined between both studies, the reasoning being such differences reflect treatment resistance instead of schizophrenia. Genotype data were retrieved from the CLOZUK and Psychiatric Genomics Consortium (PGC) schizophrenia studies. The output was validated using polygenic risk score (PRS) profiling of 2 independent schizophrenia cohorts with TRS and non-TRS: a prevalence sample with 817 individuals (Cardiff Cognition in Schizophrenia [CardiffCOGS]) and an incidence sample with 563 individuals (Genetics Workstream of the Schizophrenia Treatment Resistance and Therapeutic Advances [STRATA-G]). Main Outcomes and Measures: GWAS of treatment resistance in schizophrenia. The results of the GWAS were compared with complex polygenic traits through a genetic correlation approach and were used for PRS analysis on the independent validation cohorts using the same TRS definition. Results: The study included a total of 85490 participants (48635 [56.9%] male) in its GWAS stage and 1380 participants (859 [62.2%] male) in its PRS validation stage. Treatment resistance in schizophrenia emerged as a polygenic trait with detectable heritability (1% to 4%), and several traits related to intelligence and cognition were found to be genetically correlated with it (genetic correlation, 0.41-0.69). PRS analysis in the CardiffCOGS prevalence sample showed a positive association between TRS and a history of taking clozapine (r2 = 2.03%; P =.001), which was replicated in the STRATA-G incidence sample (r2 = 1.09%; P =.04). Conclusions and Relevance: In this GWAS, common genetic variants were differentially associated with TRS, and these associations may have been obscured through the amalgamation of large GWAS samples in previous studies of broadly defined schizophrenia. Findings of this study suggest the validity of meta-analytic approaches for studies on patient outcomes, including treatment resistance

    Establishing Boundaries: The Relationship That Exists between Intestinal Epithelial Cells and Gut-Dwelling Bacteria

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    The human gastrointestinal (GI) tract is a highly complex organ in which various dynamic physiological processes are tightly coordinated while interacting with a complex community of microorganisms. Within the GI tract, intestinal epithelial cells (IECs) create a structural interface that separates the intestinal lumen from the underlying lamina propria. In the lumen, gut-dwelling microbes play an essential role in maintaining gut homeostasis and functionality. Whether commensal or pathogenic, their interaction with IECs is inevitable. IECs and myeloid immune cells express an array of pathogen recognition receptors (PRRs) that define the interaction of both pathogenic and beneficial bacteria with the intestinal mucosa and mount appropriate responses including induction of barrier-related factors which enhance the integrity of the epithelial barrier. Indeed, the integrity of this barrier and induction of appropriate immune responses is critical to health status, with defects in this barrier and over-activation of immune cells by invading microbes contributing to development of a range of inflammatory and infectious diseases. This review describes the complexity of the GI tract and its interactions with gut bacteria

    Caregivers of children with fetal alcohol spectrum disorder: psychosocial factors and evidence for self-compassion as a potential intervention target

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    Objectives: Fetal alcohol spectrum disorder (FASD) is a common neurodevelopmental condition involving lifelong challenges for both children and their families. The aim of the current study was to explore experiences of caregivers of children, adolescents and young adults diagnosed with FASD. More specifically, we examined the relationship between shame, guilt, pride, selfcompassion and caregiver psychological distress. It was hypothesised that shame, guilt, pride and self-compassion would be uniquely associated with caregiver psychological distress. We also examined differences between biological and non-biological caregivers on these variables. It was hypothesised that relative to non-biological caregivers, biological parents would (i) report significantly higher levels of psychological distress, guilt and shame and (ii) report significantly lower self-compassion scores. Methods: The current study included 175 caregivers of children and young people diagnosed with FASD. Caregivers completed an online survey that included a range of standardised self-report measures that assessed psychological distress, shame, guilt, pride and self-compassion. Results: Caregiver self-compassion was negatively correlated with psychological distress, shame and guilt, and positively correlated with pride. Hierarchical multiple regression controlling for significant caregiver demographics revealed that shame, pride, guilt and self-compassion accounted for 68.1% of the variance in caregiver psychological distress. Shame and self-compassion were both unique significant factors in the final model. Some preliminary differences between caregiver groups were also found; specifically, biological parents reported higher levels of guilt compared with non-biological caregivers. Conclusions: The current findings revealed shame, pride, guilt and self-compassion were associated with caregiver psychological distress. Self-compassion and shame were identified as unique contributors to caregiver psychological distress. Future longitudinal research is required to establish if these associations may be casual, which will provide a useful starting point for further investigation into the efficacy of interventions that target self-compassion for promoting better psychological outcomes in this population

    Lactobacillus salivarius UCC118™ Dampens Inflammation and Promotes Microbiota Recovery to Provide Therapeutic Benefit in a DSS-Induced Colitis Model

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    The use of probiotics such as Lactobacillus and Bifidobacterium spp. as a therapeutic against inflammatory bowel disease (IBD) is of significant interest. Lactobacillus salivarus strain UCC118TM is a commensal that has been shown to possess probiotic properties in vitro and anti-infective properties in vivo. However, the usefulness of UCC118 TM as a therapeutic against colitis remains unclear. This study investigates the probiotic potential of Lactobacillus salivarius, UCC118™ in a mouse model of colitis. DSS-induced colitis was coupled with pre-treatment or post-treatment with UCC118TM by daily oral gavage. In the pre-treatment model of colitis, UCC118TM reduced the severity of the disease in the early stages. Improvement in disease severity was coupled with an upregulation of tissue IL-10 levels and increased expression of macrophage M2 markers. This anti-inflammatory activity of UCC118TM was further confirmed in vitro, using a model of LPS-treated bone marrow-derived macrophages. Taken together, these results suggest that UCC118TM may promote the resolution of inflammation. This was supported in a mouse model of established DSS-induced colitis whereby UCC118TM treatment accelerated recovery, as evidenced by weight, stool, histological markers and the recovery of microbiome-associated dysbiosis with an increased abundance of beneficial commensal species. These results demonstrate the potential of Lactobacillus salivarius UCC118TM as a probiotic-based therapeutic strategy to promote health through the upregulation of anti-inflammatory IL-10 and protect against dysbiosis during IBD

    Genomic Characterization of Listeria monocytogenes Isolates Associated with Clinical Listeriosis and the Food Production Environment in Ireland

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    Listeria monocytogenes is a major human foodborne pathogen that is prevalent in the natural environment and has a high case fatality rate. Whole genome sequencing (WGS) analysis has emerged as a valuable methodology for the classification of L. monocytogenes isolates and the identification of virulence islands that may influence infectivity. In this study, WGS was used to provide an insight into 25 L. monocytogenes isolates from cases of clinical infection in Ireland between 2013 and 2015. Clinical strains were either lineage I (14 isolates) or lineage II (11 isolates), with 12 clonal complexes (CC) represented, of which CC1 (6) and CC101 (4) were the most common. Single nucleotide polymorphism (SNP) analysis demonstrated that clinical isolates from mother–infant pairs (one isolate from the mother and one from the infant) were highly related (3 SNP differences in each) and also identified close similarities between isolates from otherwise distinct cases (1 SNP difference). Clinical strains were positive for common virulence-associated loci and 13 isolates harbour the LIPI-3 locus. Pulsed-field gel electrophoresis (PFGE) was used to compare strains to a database of 1300 Irish food and food processing environment isolates and determined that 64% of clinical pulsotypes were previously encountered in the food or food processing environment. Five of the matching food and food processing environment isolates were sequenced and results demonstrated a correlation between pulsotype and genotype. Overall, the work provides insights into the nature of L. monocytogenes strains currently causing clinical disease in Ireland and indicates that similar isolates can be found in the food or food processing environment
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