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de Oliveira, H.

Publications and source records attributed to de Oliveira, H..

2 recordsLinked to original sources

Collagen-Based Gut-on-Chip for in vitro modeling of intestinal barrier function and host-pathogen interactions

The human intestine, characterized by its villi and crypt structures, plays a critical role in nutrient absorption, barrier function, and host defense. However, traditional in-vitro models employing synthetic membranes like polydimethylsiloxane (PDMS) and polycarbonate (PC) often fail to accurately replicate the complex physiological environment of the intestine. To address this limitation, we developed a gut-on-chip, incorporating a porous collagen type I membrane, to better mimic the natural extracellular matrix (ECM) and create a more physiologically relevant in vitro system. Thin, porous collagen type I membranes were fabricated and characterized by linear close contact profilometry to determine their thickness, which closely approximated the in vivo intestinal basement membrane. Caco-2 cells cultured within the device exhibited the formation of villi-like structures, tight junction formation, and mucin production, demonstrating successful differentiation and functional barrier formation on the collagen membrane. We investigated the devices capacity to model host-pathogen interactions by infecting the cell layer with Candida albicans. Confocal microscopy revealed hyphal invasion of the epithelial cells, and permeability assays demonstrated increased layer permeability following infection, highlighting the devices ability to replicate infection processes and their impact on barrier integrity. This gut-on-chip, by integrating physiological membrane and replicating key structural and functional aspects of the intestine, offers a promising platform for studying intestinal physiology and host-pathogen dynamics.

bioengineering↗

Autophagy driven by VPS34 enables differentiated cell plasticity and cancer initiation

Differentiated cell plasticity and autophagy are fundamental mechanisms of tissue repair. To investigate their integration to maintain tissue homeostasis, we developed a unique model in which VPS34, the highly conserved class III PI3K that promotes autophagic flux, was inactivated in pancreatic exocrine cells, recognised study models. Using scRNAseq, we found that VPS34-null acinar cells evolved towards a transcriptional identity present at low levels in mouse and human pancreas. Functionally, it unexpectedly prevented transdifferentiation, chronic pancreatitis and precancer initiation triggered by stressors. Mechanistically, the newly differentiated cell state was less susceptible to cancer promotion by oncogenic KRAS, through reduced class I PI3K and increased lysosomal degradation of pro-inflammatory REG3A. This result opens the so far unreachable possibility of strategies for protection from environmentally induced cancer initiation.

pathology↗