Biology subjects

Mayhew, C. N.

Publications and source records attributed to Mayhew, C. N..

4 recordsLinked to original sources

bioRxiv2025

Mortality Risk-Stratified Septic Serum Depresses Contractility and Mitochondrial Function in Human Induced Pluripotent Stem Cell-Derived Cardiomyocytes

BackgroundSepsis-associated myocardial dysfunction (SAMD) is common in children with septic shock, is independently associated with mortality, and has no disease-modifying treatments. Differences in murine cardiomyocyte biology and repeated failures to translate discoveries into novel therapies for septic shock underscore a key translational need for human-relevant disease modeling. We sought to investigate human induced pluripotent stem cell-derived cardiomyocytes (iPSC-CMs) exposed to mortality risk-stratified septic serum as a model of SAMD. MethodsSerum from children with septic shock (n=120) was stratified by Pediatric Sepsis Biomarker Risk Model (PERSEVERE) II mortality probability as low, intermediate, or high risk. We conducted aptamer-based proteomic analysis of septic serum to determine differentially expressed proteins in children with high compared to low mortality risk. We treated iPSC-CMs with risk-stratified septic serum and defined contractile and mitochondrial functional and transcriptomic responses. ResultsWe found 612 differentially expressed proteins in children with high mortality probability, most prominently interleukins (IL)-6 and -8. High-risk septic serum reversibly depressed iPSC-CM contractility as measured by percent shortening, while low-risk septic serum had no impact. Further, high-risk septic serum depressed basal mitochondrial respiration, maximum uncoupled respiration, and coupled oxidative phosphorylation in iPSC-CMs relative to low-risk serum. We identified distinct patterns of gene expression due to risk-stratified serum with 5,293 differentially expressed genes, including upregulation of acute phase reactants and apolipoproteins and downregulation of chemokines, as well as transcriptional changes reflective of chronic IL-6 and IL-8 signaling. ConclusionsSeptic serum from children with high mortality risk exhibited distinct proteomic signatures, notably enriched for IL-6 and IL-8. Human iPSC-CMs differentially responded to risk-stratified septic serum, recapitulating phenotypic features of SAMD including reversible contractility depression and mitochondrial dysfunction with high-risk septic serum. These findings establish mortality risk-stratified septic serum exposure of iPSC-CMs as a human-relevant translational platform to interrogate mechanisms of myocardial dysfunction in septic shock.

immunology↗

bioRxiv2025

Patient-Specific Midbrain Organoids with CRISPR Correction Reveal Disease Mechanisms and Enable Therapeutic Evaluation in Neuronopathic Gaucher Disease

Neuronopathic Gaucher disease (nGD) is a lysosomal storage disorder caused by GBA1 mutations, leading to defective acid {beta}-glucosidase (GCase) and accumulation of glycosphingolipid substrates, causing inflammation and neurodegeneration. Patients with nGD manifest severe neurological symptoms, but current animal models fail to fully recapitulate human condition, posing a major barrier to the development of effective therapies targeting the brain. To bridge this gap, we have developed midbrain-like organoids (MLOs) from human induced pluripotent stem cells (hiPSCs) of nGD patients with GBA1L444P/P415R and GBA1L444P/RecNcil mutations to model nGD brain pathogenesis. These nGD MLOs exhibited GCase deficiency, resulting in diminished enzymatic function, accumulation of lipid substrates, widespread transcriptomic changes, and impaired dopaminergic neuron differentiation, mirroring nGD pathology. GBA1 mutation correction mediated by CRISPR/Cas9 restored GCase activity, normalized lipid substrate levels, and rescued dopaminergic neuron function, confirming the causal role of GBA1 mutations during early brain development. Using this novel platform, we further evaluated therapeutic strategies, including SapC-DOPS nanovesicles delivering GCase, AAV9-GBA1 gene therapy, and substrate reduction therapy with GZ452, a glucosylceramide synthase inhibitor currently under clinical investigation. These treatments either restored GCase activity, reduced lipid substrate accumulation, improved autophagic and lysosomal abnormalities, or ameliorated dysregulated genes involved in neural development. These patient-specific, 3D neural models offer a transformative, physiologically relevant platform for unravelling disease mechanisms and accelerating the discovery of therapies for patients with nGD.

neuroscience↗

bioRxiv2025

Engineering Large-Scale and Innervated Functional Human Gut for Transplantation

A confined culture system (CCS) establishes methods to generate complex functional human gastrointestinal tissues. This approach yields large-scale innervated small intestinal, colonic and gastric organoids with an elongated tubular shape for both in vitro and in vivo studies. Transcriptomic and electrophysiological data demonstrate the co-development of a functional de novo enteric nervous system, which is absent from conventional organoids. When compared to traditional methods, CCS derived small intestinal, colonic and gastric organoids reached maturation supporting transplantation in half of the time, resulting in enhanced engraftment rates and sizes. Murine luminal content exposure within CCS organoids in vivo further augmented function, supporting the potential translational benefits required to model complex intestinal diseases. In summary, the CCS methodology simplifies current protocols while adding complexity and expediting the generation of clinically relevant functional gut tissues.

bioengineering↗

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↗