Biology subjects

Gorkiewicz, G.

Publications and source records attributed to Gorkiewicz, G..

4 recordsLinked to original sources

bioRxiv2026

Host-derived bile acids drive dysbiosis by selecting bile-resistant epimerizing bacteria in inflammatory bowel disease

Microbial dysbiosis is a hallmark of inflammatory bowel diseases (IBD); however, its drivers and impact on disease pathophysiology are poorly understood. Applying neural network-based feature attribution to metabolomics and metagenomics datasets from >5000 individuals, we identified epimerized host derived bile acids (BAs) produced by microbial hydroxysteroid dehydrogenases (HSDHs) as a novel hallmark of IBD-associated dysbiosis. Epimerized BAs reduce FXR activity in intestinal epithelial cells and dampen their production of FGF19, a negative feedback regulator of host-derived bile acid (HBA) production in the liver. Increased HBA levels drive colonic epithelial remodeling by impacting goblet cell maturation and select for HSDH-carrying bacteria that transform bactericidal HBA into less toxic, epimerized forms. Confirming the translational relevance of these findings, we demonstrated that high HBA levels limit fecal microbiota transplant engraftment and show that BA sequestering drugs support microbiome recovery in patients with high HBA levels. Together, we discover that elevated HBAs deplete BA-sensitive commensals and favor the growth of HSDH-encoding pathobionts that disrupt host BA feedback signaling, establishing a causal link between changes in microbial ecology and IBD pathophysiology.

microbiology↗

bioRxiv2025

Methanobrevibacter smithii associates with colorectal cancer through trophic control of the cancer bacteriome

The human gut is colonized by trillions of microbes that influence the health of their human host. Whereas many bacterial species have now been linked to a variety of different diseases, the involvement of Archaea in human disease remains elusive. Here we searched for gut archaeal signatures of disease by screening 19 cross-sectional clinical studies comprising more than 1,800 individuals. We found that associations between Archaea and medical disorders are common but highly variable and are dominated by a significant increase of Methanobrevibacter smithii in colorectal cancer (CRC) patients. Metabolic modelling and in vitro co-culture identified distinct mutualistic interactions of M. smithii with CRC-causing bacteria such as Fusobacterium nucleatum, including metabolic enhancement. Metabolomics further revealed archaeal-derived compounds with tumor-modulating properties. This provides the first mechanistic link between human gut archaeome and CRC and highlights its role in modulating health in humans through trophic control of the resident bacteriome.

microbiology↗

bioRxiv2023

Fecal microbiota transplantation (FMT) from healthy and bipolar donors elicits distinct emotional behaviors and gut-brain metabolite profiles in mice

Bipolar disorder (BD) is a chronic mood disorder characterized by recurrent episodes of depression and (hypo-) mania. The gut microbiome is a potential avenue through which metabolic signaling, inflammatory pathways, environmental factors, and genetics influence BD pathogenesis via the gut-brain axis. Fecal microbiota transplantation (FMT) is a powerful translational tool for investigating the connections between the gut microbiome and BD, and there is evidence FMT can transfer affective symptoms of BD from humans to mice. In this study, we compared the behavior, gut-brain metabolomic profiles, and inflammatory marker expression in two groups of adult female C57BL/6J mice, one receiving FMT from a human donor with BD in a mixed episode ( HAM-D = 20, YMRS = 14) and another receiving FMT from a mentally healthy weight and age-matched control donor without BD (HAM-D and YMRS = 0). Here, we demonstrate that mice receiving FMT from individuals with BD had an increased abundance of Bacteroidota and decreased abundances of Parabacteroides merdae and Akkermansia muciniphila associated with altered levels of fecal metabolites, short-chain fatty acids, and related gut hormone expression relative to mice receiving control donor FMT. BD mice also exhibited differential regulation of several metabolites and inflammatory markers in the amygdala, with glycine being the most prominently affected. Furthermore, BD mice displayed increased anxiety-like behavior and decreased sociability, indicating that aspects of the behavioral phenotype of BD are transferable from humans to mice via FMT. Taken together, these findings implicate gut-brain signaling in the physiological and behavioral changes observed in our BD-FMT mouse model.

microbiology↗

bioRxiv2021

Altered fibrin clot structure contributes to thrombosis risk in severe COVID-19

The high incidence of thrombotic events suggests a possible role of the contact system pathway in COVID-19 pathology. Here, we demonstrate altered levels of factor XII (FXII) and its activation products in two independent cohorts of critically ill COVID-19 patients in comparison to patients suffering from severe acute respiratory distress syndrome due to influenza virus (ARDS-influenza). Compatible with this data, we report rapid consumption of FXII in COVID-19, but not in ARDS-influenza, plasma. Interestingly, the kaolin clotting time was not prolonged in COVID-19 as compared to ARDS-influenza. Using confocal and electron microscopy, we show that increased FXII activation rate, in conjunction with elevated fibrinogen levels, triggers formation of fibrinolysis-resistant, compact clots with thin fibers and small pores in COVID-19. Accordingly, we observed clot lysis in 30% of COVID-19 patients and 84% of ARDS-influenza subjects. Analysis of lung tissue sections revealed wide-spread extra- and intra-vascular compact fibrin deposits in COVID-19. Together, our results indicate that elevated fibrinogen levels and increased FXII activation rate promote thrombosis and thrombolysis resistance via enhanced thrombus formation and stability in COVID-19.

biochemistry↗