Biology subjects

Stefani, C.

Publications and source records attributed to Stefani, C..

5 recordsLinked to original sources

bioRxiv2026

UC-associated autoantibodies to αvβ6 inhibit mucosal TGFβ activation and predispose to intestinal inflammation

Ulcerative colitis (UC) is characterized by epithelial barrier dysfunction and dysregulated mucosal immune responses; however, the mechanisms driving disease onset remain poorly defined. Autoantibodies against the epithelial-restricted integrin v{beta}6 are a highly specific biomarker of UC that can precede clinical diagnosis by up to 10 years. Because v{beta}6 activates TGF{beta} at epithelial surfaces, we hypothesized that UC-associated v{beta}6 autoantibodies inhibit mucosal TGF{beta} activation and disrupt epithelial homeostasis. We showed that v{beta}6 autoantibodies were enriched in UC and that IgG from autoantibody-positive individuals inhibited v{beta}6-dependent activation of TGF{beta}. v{beta}6 blockade dampened TGF{beta} signaling and altered differentiation-associated gene programs in human intestinal epithelial cells. In mice, deletion of v caused expansion of inflammation-associated goblet cells in the colon and changes in intestinal immune cells. Using a novel mouse model, we showed that v{beta}6-specific autoantibody disrupted epithelial-immune crosstalk and increased susceptibility to DSS colitis. Together, these findings establish anti-v{beta}6 autoantibodies as active inhibitors of epithelial TGF{beta} signaling, constituting a de facto anti-cytokine response, rather than passive biomarkers. By linking preclinical seropositivity to impaired epithelial signaling and heightened susceptibility to colitis, this work identifies epithelial v{beta}6-dependent TGF{beta} activation as a pathway that may be leveraged to modify disease risk or limit disease severity. One Sentence SummaryUC-associated autoantibodies impair epithelial TGF{beta} activation, alter mucosal homeostasis, and predispose to colitis.

immunology↗

bioRxiv2025

The E. coli CNF1 toxin induces fetal reprogramming of intestinal stem cells and a serrated colorectal cancer transcriptional signature in organoids

Mechanistic insights are essential to understand how gut microbiota pathobionts contribute to tumorigenesis, given the mounting evidence linking them to colorectal cancer. We report a higher prevalence of the Rho GTPases-targeting cnf1 toxin gene from Escherichia coli in the microbiota of early-stage, proximal colorectal cancer. Comparative gene set enrichment analysis reveals a concordant serrated pathway signature between colorectal cancer tissue of patients colonized with cnf1+ bacteria and CNF1-treated mouse intestinal organoids. RNA sequencing of organoids shows that CNF1 induces a fetal-like transcriptional reprogramming. Using integrated approaches, we demonstrate that CNF1 reprograms Lgr5 stem cells into a Ly6a/Sca-1 fetal-like state, that exhibits enhanced stemness potential. This reprogramming is preceded by a Yap/Taz-driven early transcriptional program and nuclear translocation of Yap. Functional analyses identify a RhoA/Rock-Yap/Taz-dependent transition to Ly6a/Sca-1 stem cells, highlighting a mechanistic link between bacterial effectors and stem cell plasticity in colorectal tumorigenesis.

cancer biology↗

bioRxiv2025

Infants who develop BPD have an airway endotype defined by vimentin expression and ciliary loss

RationaleBronchopulmonary Dysplasia (BPD) results from abnormal lung development after preterm birth, with structural deficits at every respiratory tree level. BPD with lower airway disease is emerging as a clinically significant phenotype with increased mortality, and there is a significant knowledge gap in the molecular mechanisms whereby preterm birth disrupts normal airway development. ObjectivesTo develop a human model of lower airway disease after preterm birth and to characterize a molecular endotype of evolving BPD (eBPD) at baseline and in response to injury. MethodsWe used a combination of an ex vivo organotypic Airway Epithelial Cell (AEC models) and well-characterized pathologic and transcriptomic patient samples for quantitative immunohistochemistry and RNA sequencing analyses. Measurements and Main ResultsCompared to AECs from healthy patients, eBPD- derived AECs have a molecular endotype of reduced proliferation, impaired differentiation to ciliated epithelium, and an expanded vimentin-positive population with a transcriptional shift toward stromal cell-associated genes. With hyperoxia exposure, eBPD-derived AECs exhibited a pronounced vimentin response ex vivo, which parallels the increased vimentin expression of airway cells observed in lung tissue from human infants with BPD. ConclusionsIn this organotypic model of neonatal airway differentiation, we find that infants with eBPD have impaired differentiation, increased expression of vimentin, and concomitant loss of cilia, with an exaggerated increase in vimentin expression after hyperoxia injury, findings that mimic the effects of prematurity in airway cells in human patients. These data provide a foundation for future mechanistic studies interrogating the role of intermediate filaments in epithelial differentiation and repair.

cell biology↗

bioRxiv2022

Caveolae govern plasma membrane mechanics to protect cells against EDIN B-induced transcellular tunnel formation and lethality from S. aureus septicaemia

Large transcellular pores elicited by bacterial mono-ADP-ribosyltransferase (mART) exotoxins inhibiting the small RhoA GTPase compromise the endothelial barrier. Recent advances in biophysical modeling point towards membrane tension and bending rigidity as the minimal set of mechanical parameters determining the nucleation and maximal size of transendothelial cell macroaperture (TEM) tunnels induced by bacterial RhoA-targeting mART exotoxins. We report that cellular depletion of caveolin-1, the membrane-embedded building block of caveolae, and depletion of cavin-1, the master regulator of caveolae invaginations, increase the number of TEMs per cell. The enhanced occurrence of TEM nucleation events correlates with a reduction of cell height, due to the increase of cell spreading and decrease of cell volume, which, together with the disruption of RhoA-driven F-actin meshwork, favor membrane apposition for TEM nucleation. Strikingly, caveolin-1 specifically controls the opening speed of TEMs leading to their dramatic 5.4-fold larger widening. Consistent with the increase of TEM density and width in siCAV1 cells, we record a higher lethality in caveolin-1-deficient mice subjected to a catalytically active mART exotoxin targeting RhoA during staphylococcal bloodstream infection. Combined theoretical modeling with independent biophysical measurements of plasma membrane bending rigidity point toward a specific contribution of caveolin-1 to membrane stiffening in addition to the role of cavin-1/caveolin-1-dependent caveolae in the control of membrane tension homeostasis.

biophysics↗

bioRxiv2020

Ctenophore immune cells produce chromatin traps in response to pathogens and NADPH-independent stimulus

The formation of extracellular DNA traps (ETosis) is a first response mechanism by specific immune cells following exposure to microbes 1,2. Initially characterized in vertebrate neutrophils, cells capable of ETosis have been discovered recently in diverse non-vertebrate taxa 3 4-6. To assess the conservation of ETosis between evolutionarily distant non-vertebrate phyla, we observed and quantified ETosis using the model ctenophore Mnemiopsis leidyi and the oyster Crassostrea gigas. Here we report that ctenophores - thought to have diverged very early from the metazoan stem lineage 7-10- possess immune cell types capable of phagocytosis and ETosis. We demonstrate that both Mnemiopsis and Crassostrea immune cells undergo ETosis after exposure to diverse microbes and chemical agents that stimulate ion flux. Our results support ETosis as an evolutionarily ancient metazoan defense against pathogens.

evolutionary biology↗