Biology subjects

Breault, D.

Publications and source records attributed to Breault, D..

10 recordsLinked to original sources

bioRxiv2026

Neural Activation of Human Primary Intestinal Enteroendocrine L-cells

Intestinal enteroendocrine L-cells play a central role in metabolic homeostasis by secreting the gut hormones GLP-1 and PYY, but whether and how neural signals regulate human L-cell function remains poorly understood. This gap reflects the limited availability of human model systems enriched for mature L-cells. Here, we establish a differentiation strategy that generates human donor-derived ileal organoids with markedly increased L-cell abundance, enabling functional interrogation of L-cell physiology in their basal state. Using this system, we show that cholinergic and adrenergic stimuli activate L-cells, triggering calcium influx and secretion of GLP-1 and PYY. Pharmacological analysis reveals that cholinergic regulation of human L-cells is mediated predominantly through M3 muscarinic receptors, while adrenergic regulation is mediated through the {beta}1 adrenergic receptor. Neurotransmitter-evoked activation also initiates gap junction-dependent calcium waves that propagate across the intestinal epithelium; however, disruption of epithelial coupling by abolishing calcium propagation does not impair hormone secretion. Together, these findings identify L-cells as integrative hubs that couple neural signals to gut hormone secretion and epithelial calcium waves, providing mechanistic insight into the gut-brain axis and how the nervous system regulates intestinal endocrine function in human intestine.

cell biology↗

bioRxiv2026

Early-life mucosal T cells direct intestinal stem cell fate via a coordinated developmental program

Although early-life immunity was once considered immature, the human fetal immune system is dynamic and compartmentalized by the second trimester. By 21 weeks of gestation, T lymphocytes become a major immune population in the fetal small intestine (SI), yet their functional roles within this tissue remain largely undefined. To explore their unique contributions to intestinal development, we established an ex vivo co-culture system in which mucosal T cells isolated from fetal, neonatal, or adult SI donors were cultured with tissue-derived 3D SI organoids derived from various ages. Homeostatic early-life (fetal and neonatal) SI T cells uniquely promoted organoid generation, a metric of stem cell renewal, by upregulating cell cycle-associated gene programs. These early-life T cells also directed intestinal stem cell differentiation toward the secretory lineage in both growth and differentiation phase, highlighting that T cells poise stem cells to adopt secretory fates. T cells from infants with necrotizing enterocolitis (NEC) - an inflammatory intestinal disease affecting predominantly preterm infants - failed to activate these same programs, suggesting a pathologic role for T cells in NEC. T cells from the adult SI similarly failed to support organoid growth or differentiation, revealing developmentally specialized, nonimmune functions for early-life T cells in the intestine. Similarly, T cells derived from cord blood did not enhance organoid generation, indicating that this function is not necessarily a generalized feature of early-life T cells but rather is restricted to mucosal T cells. Organoids derived from adults or NEC, however, could re-enter regenerative states when co-cultured with fetal T cells, indicating that fetal T cells can restore stem cell self-renewal across developmentally and disease-imposed states. We further identified that T cell-derived soluble factors alone were insufficient to modulate intestinal stem cell fate, implying the need for physical interactions. Concordant with this finding, we report that T cells heavily localize to the stem cell niche during prenatal development, where they express factors involved in Notch, Wnt, and growth factor signaling to support fetal stem cell function. Collectively, these findings reveal a coordinated developmental program in which fetal SI T cells balance stem cell self-renewal and differentiation, identifying a developmental immune-epithelial axis that can be harnessed to restore intestinal regeneration.

immunology↗

bioRxiv2026

Blautia wexlerae Transforms Dietary Fatty Acids to Activate Enteroendocrine Signaling and Improve Metabolic Health in Mice and Humans

Metabolites produced by the gut microbiome influence host metabolic health, but how this occurs remains incompletely defined. Here, we report that a common human gut commensal, Blautia wexlerae, converts dietary fats into bioactive metabolites that induce gut hormone production to affect glucose metabolism and suppress appetite. We found that colonization with Blautia wexlerae correlated with healthier eating behaviors in humans. Blautia wexlerae encodes a unique acyl transferase and is capable of producing acyl amines from nutrient substrates. These Blautia acyl amines stimulated human enteroendocrine cells to secrete GLP-1 and other gut peptide hormones more potently than endogenously produced acyl amines. When fed to mice, acyl amines improved glycemic control and decreased appetite. In humans, higher stool levels of Blautia DNA encoding acyl amine synthesis genes correlated with leanness and decreased dietary fat intake. These results define a mechanism of action for how Blautia wexlerae affects host metabolic control.

microbiology↗

bioRxiv2025

Rho-ROCK signaling and α-Catenin mediate β-Catenin-driven hyperplasia in the adrenal via adherens junctions

How {beta}-Catenin ({beta}Cat) mediates tissue hyperplasia is poorly understood. To explore this, we employed the adrenal cortex as a model system given its stereotypical spatial organization and the important role {beta}Cat plays in homeostasis and disease. For example, excessive production of aldosterone by the adrenal cortex (primary aldosteronism, PA) constitutes a significant cause of cardiovascular morbidity, which has been associated with {beta}Cat gain-of-function ({beta}Cat-GOF). Adherens junctions (AJs) connect the actin cytoskeletons of adjacent zona Glomerulosa (zG) cells via a cadherin/{beta}Cat/-Catenin (Cat) complex and mediate aldosterone production. Whether {beta}Cat-GOF drives zG hyperplasia, a key feature of PA, via AJs is unknown. Here, we show that aldosterone secretagogues (K+, AngII) and {beta}Cat-GOF mediate AJ enrichment via Rho-ROCK-actomyosin signaling. In addition, Rho-ROCK inhibition leads to altered zG rosette morphology and decreased aldosterone production. Mice with zG-specific {beta}Cat-GOF demonstrate increased AJ formation and zG hyperplasia, which was blunted by Rho-ROCK inhibition and deletion of Cat. Further, analysis of human aldosterone-producing adenomas (APAs) revealed high levels of {beta}Cat expression were associated with increased membranous expression of K-Cadherin. Together, our findings identify Rho-ROCK signaling and Cat as key mediators of AJ enrichment and {beta}-Catenin-driven hyperplasia. One Sentence SummaryThis study demonstrates that {beta}-Catenin-driven hyperplasia in the adrenal cortex, a key feature of primary aldosteronism, is mediated through Rho-ROCK signaling and -Catenin-dependent stabilization of adherens junctions, with significant implications for patients with primary aldosteronism. HighlightsO_LIRho-ROCK signaling drives AJ enrichment in the adrenal C_LIO_LIROCK inhibition via fasudil blunts aldosterone production C_LIO_LI{beta}Cat drives adrenal hyperplasia via enhanced AJ enrichment C_LIO_LIROCK inhibition or [a]Cat deletion block zG hyperplasia C_LI

cell biology↗

bioRxiv2025

Loss of WNT2B Increases Progression from Dysplasia to Colorectal Cancer

Colorectal cancer (CRC) is the third most common cancer and the second leading cause of cancer-related deaths in the United States, and upregulation of the WNT pathway is a primary driver in most cases. However, the role of individual WNT proteins in the development of CRC remains poorly understood. Our previous studies demonstrated that WNT2B loss-of-function leads to severe intestinal enteropathy in humans and increases chemically-induced colitis in mice, suggesting a protective function in the colon. Therefore, we investigated how loss of WNT2B affects CRC development. We used azoxymethane (AOM)/dextran sodium sulfate (DSS) to model colitis-associated cancer (CAC) and AOM-induced mutagenesis to model sporadic CRC. We measured the number and size of tumors and performed histopathological and molecular analyses. We also analyzed the Cancer Genome Atlas to evaluate WNT2B expression in human colon cancer. In CAC and CRC mouse models, Wnt2b KO mice showed decreased survival and enhanced tumor burden. Moreover, Wnt2b KO mice had larger tumors and enhanced dysplasia, with a higher frequency of animals progressing from adenomas to adenocarcinomas compared to control littermates. Wnt2b KO animals frequently presented with intestinal bleeding and rectum prolapse, which resembles obstructive CRC. Furthermore, WNT2B expression was downregulated in human CRC samples compared to healthy controls, which predicted a significantly lower patient survival. These findings support the conclusion that WNT2B is required for maximal resistance against tumorigenesis and raise the possibility that selectively increasing WNT2B signaling may be a useful colon cancer prevention strategy. SignificanceWNT2B loss-of-function increases colon cancer tumorigenesis. Targeting WNT2B may represent a novel strategy for intestinal diseases with a high risk of neoplastic transformation, potentially decreasing the progression to cancer development.

cancer biology↗

bioRxiv2025

Mesenchymal WNT2B is Required for the Development and Function of the Human Intestine

Background and AimsWNT2B mutations result in Diarrhea-9 (DIAR9), a congenital diarrhea syndrome with an extreme phenotype and unique histological defects. Attempts to model DIAR9 in rodents and study patient epithelial tissue have not been able to fully reproduce the human phenotype, making understanding this condition challenging. Here, we aimed to interrogate the mechanisms and the specific cellular compartment contributing to DIAR9 using a human intestinal organoid model. MethodsHuman intestinal organoids (HIOs) generated from both a patient-derived WNT2BR69*iPSC line and a control line were transplanted into immunocompromised mice for 10 weeks. Grafts were harvested and histologically compared. Bulk RNA sequencing was performed on both organoid groups and on patient-biopsy derived enteroids. In vitro recombination experiments were performed to describe the causative cellular compartment. ResultsLive and histological imaging revealed partial epithelial delamination in WNT2BR69*HIOs, which was absent in controls. A significant number of crypts in WNT2BR69* HIOs lacked OLFM4, a surrogate marker of stem cell activity. Key transcriptomic pathways altered between groups included trafficking of apical digestion proteins, which was confirmed via immunofluorescence. Patient derived enteroid proteomic analysis revealed similar results. Recombination experiments in HIOs revealed that while both epithelial and mesenchymal WNT2B are important for stem cell function, lack of mesenchymal WNT2B was sufficient to elicit the phenotype. ConclusionWe demonstrated that mesenchymal WNT2B is critical for supporting human intestinal epithelial development and function.

developmental biology↗

bioRxiv2024

Non-canonical Wnt signaling triggered by WNT2B drives adrenal aldosterone production

The steroid hormone aldosterone, produced by the zona glomerulosa (zG) of the adrenal gland, is a master regulator of plasma electrolytes and blood pressure. While aldosterone control by the renin-angiotensin system is well understood, other key regulatory factors have remained elusive. Here, we replicated a prior association between a non-coding variant in WNT2B and an increased risk of primary aldosteronism, a prevalent and debilitating disease caused by excessive aldosterone production. We further show that in both mice and humans, WNT2B is expressed in the mesenchymal capsule surrounding the adrenal cortex, in close proximity to the zG. Global loss of Wnt2b in the mouse results in a dysmorphic and hypocellular zG, with impaired aldosterone production. Similarly, humans harboring WNT2B loss-of-function mutations develop a novel form of Familial Hyperreninemic Hypoaldosteronism, designated here as Type 4. Additionally, we demonstrate that WNT2B signals by activating the non-canonical Wnt/planar cell polarity pathway. Our findings identify WNT2B as a key regulator of zG function and aldosterone production with important clinical implications. HighlightsO_LIWNT2B variant is associated with increased risk for primary aldosteronism C_LIO_LIWnt2b knock-out mice show defects in adrenal morphology C_LIO_LIWnt2b knock-out mice have hyperreninemic hypoaldosteronism C_LIO_LIWNT2B activates non-canonical Wnt/planar cell polarity signaling C_LIO_LIWNT2B deficiency causes a new form of familial hyperreninemic hypoaldosteronism C_LI

genetics↗

bioRxiv2022

Loss of SUMO-specific protease 2 causes isolated glucocorticoid deficiency by blocking zonal transdifferentiation

SUMOylation is a dynamic posttranslational modification, that provides fine-tuning of protein function involved in the cellular response to stress, differentiation, and tissue development. In the adrenal cortex, an emblematic endocrine organ that mediates adaptation to physiological demands, the SUMOylation gradient is inversely correlated with the gradient of cellular differentiation raising important questions about its role in functional zonation and the response to stress. Considering that SUMO-specific protease 2 (SENP2), a deSUMOylating enzyme, is upregulated by ACTH/PKA signalling within the zona Fasciculata (zF), we generated mice with adrenal-specific Senp2 loss to address these questions. Disruption of SENP2 activity in steroidogenic cells leads to specific hypoplasia of the zF, a blunted reponses to ACTH and isolated glucocorticoid deficiency. Mechanistically, overSUMOylation resulting from SENP2 loss shifts the balance between ACTH/PKA and WNT/{beta}-catenin signalling leading to repression of PKA activity and ectopic activation of {beta}-catenin. At the cellular level, this blocks transdifferentiation of {beta}-catenin-positive zona Glomerulosa cells into zF cells and sensitises them to premature apoptosis. Our findings indicate that the SUMO pathway is critical for adrenal homeostasis and stress responsiveness.

physiology↗

bioRxiv2021

Stiffness Regulates Intestinal Stem Cell Fate

Does fibrotic gut stiffening caused by inflammatory bowel diseases (IBD) direct the fate of intestinal stem cells (ISCs)? To address this question we first developed a novel long-term culture of quasi-3D gut organoids plated on hydrogel matrix of varying stiffness. Stiffening from 0.6kPa to 9.6kPa significantly reduces Lgr5high ISCs and Ki67+ progenitor cells while promoting their differentiation towards goblet cells. These stiffness-driven events are attributable to YAP nuclear translocation. Matrix stiffening also extends the expression of the stemness marker Olfactomedin 4 (Olfm4) into villus-like regions, mediated by cytoplasmic YAP. We next used single-cell RNA sequencing to generate for the first time the stiffness-regulated transcriptional signatures of ISCs and their differentiated counterparts. These signatures confirm the impact of stiffening on ISC fate and additionally suggest a stiffening-induced switch in metabolic phenotype, from oxidative phosphorylation to glycolysis. Finally, we used colon samples from IBD patients as well as chronic colitis murine models to confirm the in vivo stiffening-induced epithelial deterioration similar to that observed in vitro. Together, these results demonstrate stiffness-dependent ISC reprograming wherein YAP nuclear translocation diminishes ISCs and Ki67+ progenitors and drives their differentiation towards goblet cells, suggesting stiffening as potential target to mitigate gut epithelial deterioration during IBD.

cell biology↗

bioRxiv2019

Niche-inspired synthetic matrices for epithelial organoid culture

Epithelial organoids are now an important tool in fields ranging from regenerative medicine to drug discovery. Organoid culture requires Matrigel, a complex, tumor-derived, extracellular matrix. An alternative completely synthetic matrix could improve culture reproducibility, clarify mechanistic phenomena, and enable applications involving human implantation. Here, we designed synthetic matrices with tunable biomolecular and biophysical properties that allowed us to identify critical gel parameters in organoid formation. Inspired by known epithelial integrin expression in the proliferative niche of the human intestine, we identified an 2{beta}1 integrin-binding peptide as a critical component of the synthetic matrix that supports human duodenal colon and endometrial organoid propagation. We show that organoids emerge from single cells, retain their proliferative capacity, are functionally responsive to basolateral stimulation and have correct apicobasal polarity upon induction of differentiation. The local biophysical presentation of the cues, rather than bulk mechanical properties, appears to be the dominant parameter governing epithelial cell proliferation and organoid formation in the synthetic matrix.

bioengineering↗