Biology subjects

O'Connell, A. E.

Publications and source records attributed to O'Connell, A. E..

8 recordsLinked to original sources

bioRxiv2026

EGFR INHIBITION PROMOTES ENTEROENDOCRINE CELL DIFFERENTIATION CONTRIBUTING TO TREATMENT-ASSOCIATED DIARRHEA

Enteroendocrine cells (EECs) are specialized sensors of the gastrointestinal (GI) epithelium that regulate gut function and systemic metabolism through hormone secretion. The molecular pathways directing intestinal stem cell (ISC) differentiation into EECs are incompletely understood due, in part, to their rarity. We sought to identify novel regulators of human EEC differentiation using a high-throughput screen of FDA-approved drugs and human duodenal organoids. Two epidermal growth factor receptor inhibitors (EGFRi) commonly used in cancer therapy and known to cause GI side effects, erlotinib and lapatinib, emerged as strong inducers of EEC differentiation, dramatically increasing chromogranin A (CHGA) expression compared to controls, while maintaining ISC function and organoid growth. EGFRi-treated organoids revealed robust and broad upregulation of EEC hormones, including serotonin (5HT), motilin (MLN), and somatostatin (SST), among others. In agreement with these findings, analysis of a patient cohort with lung cancer revealed an association with erlotinib use and increased circulating levels of the above EEC hormones compared to matched controls. Supporting a direct effect of EGFRi on EEC differentiation, mice treated with erlotinib demonstrated increased EEC numbers and hormones and showed EGFRi-associated diarrhea (EAD), a limiting side effect of these medications. Mechanistically, EGFRi induced upregulation of interferon (IFN) signaling targets during early ISC-to-EEC differentiation. Consistent with this, inhibition of Signal Transducer and Activator of Transcription 1 (STAT1) attenuated EGFRi-induced EEC differentiation. These findings provide important insight into EEC differentiation that could inform treatment strategies for EAD, metabolic diseases, and GI diseases. Brief SummaryInhibition of EGFR signaling promotes human ISC-to-EEC differentiation through activation of STAT1 signaling.

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↗

bioRxiv2025

Necrotizing enterocolitis causes increased ileal goblet cell loss in Wnt2b KO mice

WNT2B is Wnt ligand which is able to support intestinal stem cells (ISC) in culture and support the intestinal epithelium in vivo. We have previously shown that WNT2B is critical for resistance to colitis, but not small intestinal injury, in the adult mouse. WNT2B is thought to coordinate with WNT3 in supporting ISC, and we have also shown that WNT3 expression is low in the early postnatal ileum in mice. Here, we hypothesized that WNT2B may be more critical in the small intestine during early development, and we challenged Wnt2b KO mice and controls with experimental necrotizing enterocolitis (NEC) on postnatal days 5-8. Wnt2b KO mice had similar ileum histology and injury scores to control mice. Molecular analyses showed that Wnt2b KO mice have differences in Lgr5 and Tlr4 expression compared to wild type controls in untreated conditions, but under experimental NEC expression of epithelial markers and inflammatory genes associated with NEC were similar to wild type. Periodic acid Schiff positive cells were lower in the villi of Wnt2b KO mice during NEC, however expression of goblet cell markers was not different compared to wild type mice. We also used an organoid-based NEC model to highlight the epithelium in isolation and also found no impact of WNT2B KO in the setting of NEC. These data further affirm that WNT2B is critical for inflammation responses in the mouse colon, but does not appear to play a major role in the small intestine, no matter the developmental period.

developmental biology↗

bioRxiv2024

Cataloguing the postnatal small intestinal transcriptome during the period of susceptibility to necrotizing enterocolitis

In the first postnatal month, the developing mouse intestine shifts from an immature to a mature intestine that will sustain the organism throughout the lifespan. Here, we surveyed the mouse intestine in C57Bl/6 mice by bulk RNA-Seq to evaluate the changes in gene expression over time from the day of birth through 1 month of age in both the duodenum and ileum. Using trends identified in the RNA-Seq analyses, we further evaluated expression of epithelial and mesenchymal cell markers, epithelial regulators, and immune cell markers. We confirmed key changes with qRT-PCR and immunofluorescence. In addition, we compared some findings to humans using human intestinal biopsies and organoids. This dataset can serve as a reference for other groups considering the role of single molecules or molecular families in early intestinal and postnatal development, expanding the limited literature on postnatal gene expression in the developing intestine.

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↗

bioRxiv2023

WNT2B Deficiency Causes Increased Susceptibility to Colitis in Mice and Impairs Intestinal Epithelial Development in Humans

Background and aimsWNT2B is a canonical Wnt ligand previously thought to be fully redundant with other Wnts in the intestinal epithelium. However, humans with WNT2B deficiency have severe intestinal disease, highlighting a critical role for WNT2B. We sought to understand how WNT2B contributes to intestinal homeostasis. MethodsWe investigated the intestinal health of Wnt2b knock out (KO) mice. We assessed the impact of inflammatory challenge to the small intestine, using anti-CD3{chi} antibody, and to the colon, using dextran sodium sulfate (DSS). In addition, we generated human intestinal organoids (HIOs) from WNT2B-deficient human iPSCs for transcriptional and histological analyses. ResultsMice with WNT2B deficiency had significantly decreased Lgr5 expression in the small intestine and profoundly decreased expression in the colon, but normal baseline histology. The small intestinal response to anti-CD3{chi} antibody was similar in Wnt2b KO and wild type (WT) mice. In contrast, the colonic response to DSS in Wnt2b KO mice showed an accelerated rate of injury, featuring earlier immune cell infiltration and loss of differentiated epithelium compared to WT. WNT2B-deficient HIOs showed abnormal epithelial organization and an increased mesenchymal gene signature. ConclusionWNT2B contributes to maintenance of the intestinal stem cell pool in mice and humans. WNT2B deficient mice, which do not have a developmental phenotype, show increased susceptibility to colonic injury but not small intestinal injury, potentially due to a higher reliance on WNT2B in the colon compared to the small intestine. WNT2B deficiency causes a developmental phenotype in human intestine with HIOs showing a decrease in their mesenchymal component and WNT2B-deficient patients showing epithelial disorganization. Data Transparency StatementAll RNA-Seq data will be available through online repository as indicated in Transcript profiling. Any other data will be made available upon request by emailing the study authors.

molecular biology↗

bioRxiv2023

Antimicrobial peptides modulate pulmonary inflammation by altering the intestinal microbiota

Mammalian mucosal barriers secrete antimicrobial peptides (AMPs) as critical host-derived regulators of the microbiota. However, mechanisms that support homeostasis of the microbiota in response to inflammatory stimuli such as supraphysiologic oxygen remain unclear. Here, we show that neonatal mice breathing supraphysiologic oxygen or direct exposure of intestinal organoids to supraphysiologic oxygen suppress the intestinal expression of AMPs and alters the composition of the intestinal microbiota. Oral supplementation of the prototypical AMP lysozyme to hyperoxia exposed neonatal mice reduced hyperoxia-induced alterations in their microbiota and was associated with decreased lung injury. Our results identify a gut-lung axis driven by intestinal AMP expression and mediated by the intestinal microbiota that is linked to lung injury. Together, these data support that intestinal AMPs modulate lung injury and repair. Graphical Abstract O_FIG O_LINKSMALLFIG WIDTH=200 HEIGHT=185 SRC="FIGDIR/small/529700v2_ufig1.gif" ALT="Figure 1"> View larger version (66K): org.highwire.dtl.DTLVardef@800123org.highwire.dtl.DTLVardef@1caac5forg.highwire.dtl.DTLVardef@faa875org.highwire.dtl.DTLVardef@49c4e9_HPS_FORMAT_FIGEXP M_FIG C_FIG In BriefUsing a combination of murine models and organoids, Abdelgawad and Nicola et al. find that suppression of antimicrobial peptide release by the neonatal intestine in response to supra-physiological oxygen influences the progression of lung injury likely via modulation of the ileal microbiota. HighlightsO_LISupraphysiologic oxygen exposure alters intestinal antimicrobial peptides (AMPs). C_LIO_LIIntestinal AMP expression has an inverse relationship with the severity of lung injury. C_LIO_LIAMP-driven alterations in the intestinal microbiota form a gut-lung axis that modulates lung injury. C_LIO_LIAMPs may mediate a gut-lung axis that modulates lung injury. C_LI

microbiology↗