Project description:Human activity is altering the environment at a rapid pace, challenging the adaptive capacities of genetic variation within animal populations. Animals also harbor extensive gut microbiomes, which play diverse roles in host health and fitness and may help expanding host capabilities. The unprecedented scale of human usage of xenobiotics and contamination with environmental toxins describes one challenge against which bacteria with their immense biochemical diversity are particularly suited to offer solutions. To explore the paths leading to bacteria-assisted rapid adaptation, we used Caenorhabditis elegans harboring a defined microbiome, and the antibiotic neomycin as a model toxin, harmful for the worm host and neutralized to different extents by microbiome members. Worms exposed to neomycin showed delayed development and decreased survival but were protected when colonized by neomycin-resistant members of the microbiome. Through a combination of 16S gene sequencing, counting of live bacteria and behavioral assays we identified two distinct mechanisms that facilitated adaptation: gut enrichment for a neomycin-modifying strain driven by altered bacterial competition; and host avoidance behavior, which depended on the stress-activated KGB-1/JNK and enabled preference of neomycin-protective bacteria. The straightforwardness of these mechanisms suggests that bacteria-assisted host adaptation may be more common than currently appreciated, protecting animals from novel stressors. However, gut remodeling may also cause dysbiosis, and additional experiments identified fitness trade-offs including increased susceptibility to infection as well as metabolic remodeling. Extending these results to other toxins suggests yet unaccounted-for microbiome-dependent long-term consequences of toxin exposure.
Project description:We quantitatively examine inputs and outputs of the mouse gut microbiome, using isotope tracing. To determine nutrient preferences across bacteria, we traced into genus-specific bacterial protein sequences. By in vivo isotope tracer feeding, mapped the contribution of different dietary nutrients vs circulating nutrients contribution to different gut bacterial genera.
Project description:Gut bacterial β-glucuronidases (GUS) promote the toxic side effects of therapeutics by reactivating drugs from their inactive glucuronide conjugates. It is increasingly clear that the interindividual variability of bacterial GUS-producing species in the gut microbiota contributes to differential drug responses. Indeed, the anticancer drug irinotecan exhibits variable clinical toxicity outcomes that have been linked to interindividual differences in the composition of the gut microbiota. However, identification of the specific GUS enzymes responsible for drug metabolism in the context of the complexity of the human fecal microbiota has not been achieved. Here we pinpoint the specific bacterial GUS enzymes that reactivate SN-38, the active metabolite of irinotecan, from complex human fecal microbiota samples with activity-based protein profiling (ABPP). We identify and quantify gut bacterial GUS enzymes from human feces with ABPP-enabled proteomics and then integrate this information with ex vivo kinetics to reveal the specific GUS enzymes responsible for the reactivation of SN-38. The same ABPP approach also reveals the molecular basis for differential gut bacterial GUS inhibition between human fecal samples. Taken together, this work provides an unprecedented pipeline to identify the specific bacterial GUS enzymes responsible for drug-induced GI toxicity from the complexity of human feces, which may serve as highly precise biomarkers of clinical outcomes for irinotecan and other therapeutics.
Project description:This study was designed to look for differential gene expression in the annual dicot weed velvetleaf when it is grown in competition with corn relative to when it is grown in monoculture. Keywords: weed/crop competition
Project description:Imbalance in beneficial and harmful bacteria underlies gastrointestinal diseases, such as inflammatory bowel disease. Here, we demonstrated that certain E. coli strains, specifically adherent-invasive E. coli (AIEC), utilize a serine metabolism pathway to outcompete other E. coli strains in the inflamed gut. In contrast, amino acid metabolism has a minimal effect on their competitive fitness in the healthy gut. The availability of luminal serine used for the competition of E. coli is largely dependent on dietary intake, as the inflammation-induced blooms of AIEC are significantly blunted when amino acids, particularly serine, are removed from the diet. Thus, intestinal inflammation regulates the intraspecific competition between Enterobacteriaceae by eliciting their metabolic reprogramming.
Project description:Although increasing studies have proved cell competition widely involved in the growth and homeostasis of multicellular organisms is closely linked to tumorigenesis and development, the mechanistic contributions between drug resistance and tumor cell competition remain ill-defined. In this paper, we applied MS of cell competition group to determine the dominant characteristics of lenvatinib resistance and its metabolic differences in cell competition. Our results showed a vital role of HSP90-IDH1 mediated lipid accumulation in maintaining the competitive outcome of HCC drug-resistant cells via regulating lipid metabolism. HSP90-IDH1 axis could be a promising target to overcome HCC drug resistance.
Project description:we develop an interspecies pluripotent stem cell (PSC) co-culture strategy and uncover a previously unknown mode of cell competition. Interspecies PSC competition occurs during primed but not naive pluripotency, and between evolutionarily distant species. We identified genes related to NF-κB signaling pathways, among others, were upregulated in loser cells and genetic inactivation of RELA, a core component of canonical NF-κB pathway, could overcome interspecies PSC competition. We further showed that an upstream regulator of the NF-κB signaling, MYD88 innate immune signal transduction adaptor, was also involved in promoting loser PSC elimination. Suppressing interspecies PSC competition via genetic perturbation of MYD88 or P65 improved engraftment of human cells in early post-implantation mouse embryos. Our study discovers a new paradigm of cell competition and paves the way for studying evolutionarily conserved cell competition mechanisms during early mammalian development. Strategies developed here to overcome interspecies PSC competition may facilitate interspecies organogenesis between evolutionary distant species, including humans.
Project description:<p><strong>Background</strong></p><p>Antibiotic treatment has a well-established detrimental effect on the gut bacterial composition, but effects on the fungal community are less clear. Bacteria in the lumen of the gastrointestinal tract may limit fungal colonization and invasion. Antibiotic drugs targeting bacteria are therefore seen as an important risk factor for fungal infections and induced allergies. However, antibiotic effects on gut bacterial-fungal interactions, including disruption and resilience of fungal community compositions, were not investigated in humans. We analysed stool samples collected from 14 healthy human participants over three months following a 6-day antibiotic administration. We integrated data from shotgun metagenomics, metatranscriptomics, metabolomics, and fungal ITS2 sequencing. </p><p><strong>Results</strong></p><p>While the bacterial community recovered mostly over three months post treatment, the fungal community was shifted from mutualism at baseline to competition. Half of the bacterial-fungal interactions present before drug intervention had disappeared three months later. During treatment, fungal abundances were associated with the expression of bacterial genes with functions for cell growth and repair. By extending the metagenomic species approach, we revealed bacterial strains inhibiting the opportunistic fungal pathogen Candida albicans. We demonstrate in vitro how C. albicans pathogenicity and host cell damage might be controlled naturally in the human gut by bacterial metabolites such as propionate or 5-dodecenoate.</p><p><strong>Conclusions</strong></p><p>We demonstrate that antibacterial drugs have long-term influence on the human gut mycobiome. While bacterial communities recovered mostly 30-days post antibacterial treatment, the fungal community was shifted from mutualism towards competition.</p><p><br></p><p><strong>Linked data:</strong></p><p>Metagenomics has been submitted to NCBI SRA repository as projects PRJNA573821, PRJNA573905 and PRJNA579284.</p>