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Koval, J.

Publications and source records attributed to Koval, J..

6 recordsLinked to original sources

Epithelial-Intrinsic Alterations and Maladaptation to Luminal Metabolites Underlie Persistent Crohn's Disease Pathogenesis

In patients with Crohns disease, the noninflamed intestinal epithelium exhibits inflammation-like transcriptional signatures that persist even during clinical remission. However, it is unclear whether this signature is due to sustained environmental triggers or to the epitheliums intrinsic immunological adaptions. To disentangle environmental and cell-intrinsic effects on disease signatures, we used noninflamed intestinal tissue biopsies from patients with active and inactive Crohns disease, as well as control donors, to generate donor-matched organoids enriched for intestinal epithelial cells. We collected single-cell RNA-seq and single-cell ATAC-seq data from intestinal tissues, and from their matched organoids before and after stimulation with luminal metabolites of patients. This approach allowed us to distinguish between the effects of extrinsic factors and the intrinsic alterations that persist when cells are removed from their local environment. We found that organoid cells retained epithelial-autonomous disease phenotypes, even when derived from patients in remission, whereas signatures from tissue cells showed evidence of immune- and microbial-epithelial crosstalk. In contrast to healthy control organoids, organoids from Crohns disease patients exhibited selective activation of disease-associated transcriptional changes and environment-responsive inflammatory chromatin remodeling after exposure to patient-derived luminal metabolites. Overall, our study suggests that disease-associated epithelial states are shaped by both cell-intrinsic dysregulation and microenvironmental cues.

immunology↗

Epithelia mediate inflammation with myeloid cells in Crohn's disease patients under treatment

Many Crohn's disease patients fail to respond to biologic therapies targeting canonical immune pathways, and the mechanisms underlying treatment non-response remain poorly understood. Integrating single-cell and spatial transcriptomics, we generated a comprehensive mucosal atlas of 380,000 cells spanning the terminal ileum and ascending colon of healthy donors and Crohn's disease patients receiving biologics. We revealed site-specific programs centered on TNF-expressing macrophages embedded within epithelial-stromal networks: follicle-associated enterocytes dictated immune activation in the ileum, while FAP-expressing stromal cells served this role in the colon. Co-expression network analysis further identified lineage-specific programs associating non-response, including a novel epithelial marker BPIFB1 independent of known genetic risk loci. Co-expression marker Z-scores significantly differed between responders and non-responders in published datasets. Together, these findings define a non-responder-specific epithelial-stromal-immune ecosystem that sustains chronic inflammation, providing a framework for stratifying treatment resistance and informing therapeutic strategies in Crohn's disease and other barrier organ disorders.

immunology↗

MICROBIOME-MODIFIED METABOLITES PREDICT ACUTE BRAIN INJURY OUTCOME

BACKGROUNDAcute brain injury (ABI)-mediated disruption of the microbiome may potentiate inflammation and secondary brain injury (SBI). However, microbial-specific mediators and mechanisms remain unclear. METHODSThirty-five consecutive patients with ABI admitted to the neuroscience critical care unit at the University of Chicago were prospectively studied. Injury severity at hospital admission was assessed using the Injury Severity Score (ISS) and the Glasgow Coma Scale (GCS). Final neurologic function was assessed via the Glasgow Outcome Score extended (GOSe). Serum, plasma, and stool targeted metabolomics, as well as stool shotgun metagenomics, were performed on longitudinal samples collected during hospitalization. RESULTSMultivariate analysis identified microbiome-modified metabolites that were positively and negatively associated with functional outcomes after ABI. Novel identification of conjugated bile acid (BA) species and vitamin B12 precursors indicative of outcome were detected in the first collected samples (within 48 hours). Network analysis revealed greater integration of negatively associated metabolites across tissues and identified tauro-/-muricholic acid (TMCA) as central to the cross-tissue metabolomes. CONCLUSIONSMicrobiome metabolites may be useful in assessing brain injury outcomes to inform treatment. Bile acid species transformed by the gut microbiome are predictive of ABI outcome.

neuroscience↗

Microbially-catalyzed conjugation of GABA and tyramine to bile acids

Bile acids (BAs) are cholesterol-derived molecules that aid in digestion and nutrient absorption, regulate host metabolic processes, and influence physiology of the gut microbiota. Both the host and its microbiome contribute to enzymatic modifications that shape the chemical diversity of BAs in the gut. Several bacterial species have been reported to conjugate standard amino acids to BAs, but it was not known if bacteria conjugate BAs to other amine classes. Here, we show that Bacteroides fragilis strain P207, isolated from a bacterial bloom in the J-pouch of a patient with ulcerative colitis (UC) pouchitis, conjugates standard amino acids and the neuroactive amines {gamma}-aminobutyric acid (GABA) and tyramine to deoxycholic acid. We extended this analysis to other human gut isolates and identified species that are competent to conjugate GABA and tyramine to primary and secondary BAs, and further identified diverse BA-GABA and BA-tyramine amides in human stool. A longitudinal metabolomic analysis of J-pouch contents of the patient from whom B. fragilis P207 was isolated revealed highly reduced levels of secondary bile acids and a shifting BA amide profile before, during, and after onset of pouchitis, including temporal changes in several BA-GABA amides. Treatment of pouchitis with ciprofloxacin was associated with a marked reduction of nearly all BA amides in the J-pouch. Our study expands the known repertoire of conjugated bile acids produced by bacteria to include BA conjugates to GABA and tyramine and demonstrates that these molecules are present in the human gut. ImportanceBile acids (BAs) are modified in multiple ways by host enzymes and the microbiota to produce a chemically diverse set of molecules that assist in the digestive process and impact many physiological functions. This study reports the discovery of bacteria isolated from the gut of human patients that conjugate the neuroactive amines, GABA and tyramine, to BAs and demonstrates that BA-GABA and BA-tyramine amides are present in the human gut. GABA and tyramine are common metabolic products of the gut microbiota and potent neuroactive molecules, and their conjugation to BAs may influence receptor-mediated regulatory mechanisms of humans and their gut microbes.

microbiology↗

Single cell genotyping of matched bone marrow and peripheral blood cells in treatment naive and AZA-treated MDS and CMML

Progressively acquired somatic mutations in hematopoietic stem cells are central to pathogenesis in myelodysplastic syndromes (MDS) and chronic myelomonocytic leukemia (CMML). They can lead to proliferative advantages, impaired differentiation and progressive cytopenias. MDS or CMML patients with high-risk disease are treated with hypomethylating agents including 5-azacytidine (AZA). Clinical improvement does not require eradication of mutated cells and may be related to improved differentiation capacity of mutated hematopoietic stem and progenitor cells (HSPCs). However, the contribution of mutated HSPCs to steadystate hematopoiesis in MDS and CMML is unclear. To address this, we characterised the somatic mutations of individual stem, progenitor (common myeloid progenitor, granulocyte monocyte progenitor, megakaryocyte erythroid progenitor), and matched circulating (monocyte, neutrophil, naive B cell) haematopoietic cells in treatment naive and AZA-treated MDS and CMML via high-throughput single cell genotyping. The mutational burden was similar across multiple hematopoietic cell types, and even the most mutated stem and progenitor clones maintained their capacity to differentiate to mature myeloid and, in some cases, lymphoid cell types in vivo. Our data show that even highly mutated HSPCs contribute significantly to circulating blood cells in MDS and CMML, prior to and following AZA treatment. Key points* Highly mutated HSPCs contribute significantly to circulating blood cells in MDS and CMML, prior to and following AZA treatment. * The mutational burden in matched bone marrow and peripheral blood cells in MDS and CMML was similar throughout myelopoiesis.

cancer biology↗

Wetland plant evolutionary history influences soil and endophyte microbial community composition

Methane is a microbially derived greenhouse gas whose emissions are highly variable throughout wetland ecosystems. Differences in plant community composition account for some of this variability, suggesting an influence of plant species on microbial community structure and function in these ecosystems. Given that closely related plant species have similar morphological and biochemical features, we hypothesize that plant evolutionary history is related to differences in microbial community composition. To examine species-specific patterns in microbiomes, we selected five monoculture-forming wetland plant species based on the evolutionary distances among them. We detected significant differences in microbial communities between sample types (unvegetated soil, bulk soil, rhizosphere soil, internal root tissues, and internal leaf tissues) associated with these plant species based on 16S relative abundances. We additionally found that differences in plant evolutionary history were correlated with variation in microbial communities across plant species within each sample type. Using qPCR, we observed substantial differences in overall methanogen and methanotroph population sizes between plant species and sample types. Methanogens tended to be most abundant in rhizosphere soils while methanotrophs were the most abundant in roots. Given that microbes influence methane flux and that plants affect methanogen and methanotroph populations, plant species contribute to variable degrees of methane emissions. Incorporating the influence of plant evolutionary history into future modeling efforts may improve predictions of wetland methane emission since microbial community differences correlate with differences in plant evolutionary history.

ecology↗