Biology subjects

Biouss, G.

Publications and source records attributed to Biouss, G..

4 recordsLinked to original sources

bioRxiv2025

Molecular and Epigenetic Pathways Underlying Epithelial Damage and Repair in Necrotizing Enterocolitis via Multi-omics Approach

IntroductionNeonatal necrotizing enterocolitis (NEC) is a severe gastrointestinal disorder with high mortality, characterized by epithelial cell injury and compromised epithelial repair. The mechanisms underlying defective epithelial regeneration remain poorly understood despite advances in single-cell omics. Addressing these challenges is essential for elucidating the pathogenesis of NEC and identifying therapeutic targets to restore epithelial regeneration and replace the damaged epithelial layer. MethodsMulti-omics approaches were employed to investigate molecular and spatial changes in experimental NEC at epigenetic and transcriptomic levels. These included bulk RNA sequencing, single-nucleus RNA sequencing (snRNA-seq), single-nucleus assay for transposase-accessible chromatin sequencing (snATAC-seq), and multiplexed error-robust fluorescence in situ hybridization (MERFISH) for spatial transcriptomics. Complementary in vitro experiments and in vivo mouse models were utilized to evaluate NEC phenotypes, intestinal tissue morphology, and organoid formation. ResultsChanges in cell type composition, transcriptional network remodeling, and chromatin accessibility were observed in the small intestine of neonatal mice with NEC. Chromatin accessibility significantly changed in epithelial cells, highlighting their pivotal roles in NEC. A marked reduction in intestinal stem cells (ISCs) and transit-amplifying cells, along with an increased proportion of enteroendocrine cells, indicates disrupted epithelial regeneration and functional differentiation. These changes correlated with disrupted WNT signaling and stem cell maintenance genes (e.g., Lgr5, Smoc2, Axin2) and activation of inflammatory and hypoxia-related pathways (e.g., Il6, Tnf). The epigenetic regulator Ezh2 was identified as a critical factor in maintaining LGR5+ ISCs and epithelial homeostasis. Knockdown of Ezh2 reduced stemness and proliferation-related gene expression and exacerbated inflammation. Reactivation of WNT signaling restored Ezh2 and Lgr5 expression, improving intestinal regeneration. ConclusionThis study reveals dynamic transcriptomic, epigenetic, and spatial changes in NEC and highlights Ezh2 as a key regulator of LGR5+ intestinal stem cell function and epithelial regeneration. These findings provide insights into NEC pathogenesis and a basis for therapies targeting Ezh2 and WNT signaling to restore intestinal integrity. O_FIG O_LINKSMALLFIG WIDTH=200 HEIGHT=194 SRC="FIGDIR/small/647851v1_ufig1.gif" ALT="Figure 1"> View larger version (53K): org.highwire.dtl.DTLVardef@1ad89eaorg.highwire.dtl.DTLVardef@396282org.highwire.dtl.DTLVardef@172596forg.highwire.dtl.DTLVardef@4daf28_HPS_FORMAT_FIGEXP M_FIG C_FIG

pathology↗

bioRxiv2024

Amniotic fluid stem cell extracellular vesicles promote lung development via TGF-beta modulation in a fetal rat model of oligohydramnios

Oligohydramnios (decreased amniotic fluid volume for gestational age) is a severe condition associated with high morbidity and mortality mainly due to fetal pulmonary hypoplasia. Currently, there are limited treatment options to promote fetal lung development. Administration of stem cells and their derivates have shown promising regenerative properties for several fetal and neonatal diseases related to arrested lung development. Herein, we first characterized pulmonary hypoplasia secondary to oligohydramnios in a surgical rat model. Experimental induction of oligohydramnios led to impaired lung growth, branching morphogenesis (fewer airspaces with decreased Fgf10, Nrp1, Ctnnb1 expression), proximal/distal progenitor cell patterning (decreased Sox2 and Sox9 expression), and TGF-{beta} signaling. We then tested antenatal administration of extracellular vesicles derived from amniotic fluid stem cells (AFSC- EVs). In oligohydramnios lungs, AFSC-EV administration improved lung branching morphogenesis and airway progenitor cell patterning at least in part through the release of miR-93-5p. Our experiments suggest that AFSC-EV miR-93-5p blocked SMAD 7, resulting in upregulation of pSMAD2/3 and restoration of TGF-{beta} signaling. Conversely, oligohydramnios lungs treated with antagomir 93-5p transfected AFSC- EVs had decreased branching morphogenesis and TGF-{beta} signaling. This is the first study reporting that antenatal administration of stem cell derivatives could be a potential therapy to rescue lung development in fetuses with oligohydramnios. HighlightsO_LIPulmonary hypoplasia secondary to oligohydramnios in fetal rats is characterized by impaired TGF-{beta} signaling. C_LIO_LIAFSC-EV administration improves fetal lung branching morphogenesis and airway progenitor cell patterning. C_LIO_LIAFSC-EV effects are mediated at least in part via modulation of TGF-{beta} signaling by the release of miR-93-5p from AFSC-EVs. C_LI

developmental biology↗

bioRxiv2023

Unveiling fetal brain changes in congenital diaphragmatic hernia: hypoxic injury with loss of progenitor cells, neurons, and oligodendrocytes

Congenital diaphragmatic hernia (CDH) is a birth defect characterized by incomplete closure of the diaphragm, herniation of abdominal organs into the chest, and compression of the lungs and the heart. Besides complications related to pulmonary hypoplasia, 1 in 4 survivors develop neurodevelopmental impairment, whose etiology remains unclear. Using a fetal rat model of CDH, we demonstrated that the compression exerted by herniated organs on the mediastinal structures results in decreased brain perfusion on ultrafast ultrasound, cerebral hypoxia with compensatory angiogenesis, mature neuron and oligodendrocyte loss, and activated microglia. In CDH fetuses, apoptosis was prominent in the subventricular and subgranular zones, areas that are key for neurogenesis. We validated these findings in the autopsy samples of four human fetuses with CDH compared to age- and sex-matched controls. This study reveals the molecular mechanisms and cellular changes that occur in the brain of fetuses with CDH and creates opportunities for therapeutic targets.

developmental biology↗

bioRxiv2022

Amniotic fluid stem cell extracellular vesicles promote fetal lung branching and cell differentiation in experimental congenital diaphragmatic hernia

Pulmonary hypoplasia secondary to congenital diaphragmatic hernia (CDH) is characterized by impaired branching morphogenesis and differentiation. We have previously demonstrated that administration of extracellular vesicles derived from rat amniotic fluid stem cells (AFSC-EVs) rescues development of hypoplastic lungs at the pseudoglandular and alveolar stages in rodent models of CDH. Herein, we tested whether AFSC-EVs exert their regenerative effects at the canalicular and saccular stages, as these are translationally relevant for clinical intervention. To induce fetal pulmonary hypoplasia, we gavaged rat dams with nitrofen at embryonic day 9.5 and demonstrated that nitrofen-exposed lungs had impaired branching morphogenesis, dysregulated signaling pathways relevant to lung development (FGF10/FGFR2, ROBO/SLIT, Ephrin, Neuropilin 1, {beta}-catenin) and impaired epithelial and mesenchymal cell marker expression at both stages. AFSC-EVs administered to nitrofen-exposed lung explants rescued airspace density and increased the expression levels of key factors responsible for branching morphogenesis. Moreover, AFSC-EVs rescued the expression of alveolar type 1 and 2 cell markers at both canalicular and saccular stages, and restored markers of club, ciliated epithelial, and pulmonary neuroendocrine cells at the saccular stage. AFSC-EV treated lungs also had restored markers of lipofibroblasts and PDGFRA+ cells to control levels at both stages. EV tracking showed uptake of AFSC-EV RNA cargo throughout the fetal lung and an mRNA-miRNA network analysis identified that several miRNAs responsible for regulating lung development processes were contained in the AFSC-EV cargo. These findings suggest that AFSC-EV based therapies hold potential for restoring fetal lung growth and maturation in babies with pulmonary hypoplasia secondary to CDH. Graphical abstractBabies with congenital diaphragmatic hernia have hypoplastic lungs characterized by impaired branching morphogenesis and undifferentiated epithelium and mesenchyme. The authors demonstrate that amniotic fluid stem cell extracellular vesicles (AFSC-EVs) administered to rat hypoplastic fetal lungs restore branching and exert regenerative effects on epithelial and mesenchymal cells, partly through miRNA cargo transfer. AFSC-EV beneficial effects were obtained at translationally relevant timepoints. O_FIG O_LINKSMALLFIG WIDTH=200 HEIGHT=118 SRC="FIGDIR/small/475632v1_ufig1.gif" ALT="Figure 1"> View larger version (25K): org.highwire.dtl.DTLVardef@144784aorg.highwire.dtl.DTLVardef@3560acorg.highwire.dtl.DTLVardef@5dc277org.highwire.dtl.DTLVardef@18a14de_HPS_FORMAT_FIGEXP M_FIG C_FIG

developmental biology↗