Hudson Institute

Disclosure: T.J. Cole: None. J. Ng: None. V. Wang: None. M.J. Young: None. J. Yang: None. P.J. Fuller: None. The mineralocorticoid receptor (MR) is an intracellular nuclear receptor that mediates physiological actions of the adrenal steroid ligands, aldosterone and cortisol. The MR contains a C-terminal ligand-binding domain (LBD) that consists of 11 α-helices organized in an antiparallel helical sandwich. The LBD undergoes a conformational change upon aldosterone binding such that helix 12 forms a stable interaction with helices 3, 4 and 5 to create an AF-2 domain, a hydrophobic cleft on the surface of the LBD, which serves as a docking platform for transcriptional coactivators. To determine the relative contribution to MR-mediated transactivation of the MR AF-2 domain in vivo, we have used CRISPR/Cas9 gene-editing technology to introduce a previously described, AF-2 mutation, E958A, into helix 12 of the MR LBD. These mice, bred to homozygosity (MRE958A), are viable without the fatal sodium wasting phenotype, seen for MR-null and MR-DBD C603S mutant mice, which argues that AF-2 function in mice is not obligatory for MR-mediated sodium transport. Initial phenotyping shows a significant weight difference between both male and female wildtype and MRE958A mice. Metabolic cage analyses showed increased food and water intake in the MRE958A mice potentially as compensation for mild salt and fluid loss. Both plasma and urinary aldosterone levels, and plasma renin were markedly elevated. Increased renal renin mRNA levels in MRE958A mice, were further exacerbated on a low sodium diet. The adrenal gland had increased zona glomerulosa immunostaining for aldosterone synthase with evidence of zona glomerulosa hyperplasia. Given previous evidence for the importance of the MR LBD/AF2-coregulator interaction in mediating ligand-dependent transactivation, these findings of a subtle physiological phenotype in the MRE958A mice are unexpected and suggest that novel non-AF2 mediated mechanisms may play a central role in MR-mediated transactivation. Presentation: Monday, July 14, 2025

Contamination by black mold in healthcare facilities can increase patient safety incidents through respiratory problems, allergic reactions, and healthcare associated infections. Enviromental factors such as high humidity and poor air quality support black mold growth. This study aimed to evaluate environmental conditions that potentially trigger black mold proliferation and their implications for patient safety in the Emergency Department (ED). An observational method was conducted by measuring temperature, humidity, and air quality from Juli-September 2025. An observational method was conducted by measuring temperature, humidity, and air quality from Juli-September 2025. Temperature and humidity were measured using the Thermo Hygrometer HTC-2, while air quality was assessed using the LKC-1000 Particle Counter in accordance with the Ministry of Health Regulation No.40 of 2022 and the World Health Organization Air Quality Guidelines 2021. The result showed that the ED environment contained conditions conducive to black mold growth. Room humidity ranged from 66,9% to 78,3%, exceeding the recomended standard of 60%. The PM2,5 concentration in the nurse station reached 19,4 µg/m3 higher than the WHO standard of 15 µg/m3. The findings emphasized the needs for corrective measures including increasing fresh air supply, improving ventilation system with at least 6 ACH, and implementing MERV13 air filtration to reduce environmental risk associated with black mold. In conclusion, the presence of black mold can threaten patient safety; therefore, hospital environmental management interventions are necessary to suppress mold growth.

The mevalonate kinase (MVK) pathway is an essential metabolic pathway for sterol and isoprenoid synthesis. Non-sterol isoprenoids have critical biological functions in the post-translational modifications of numerous signaling molecules via prenylation, including inflammasomes. A defect in prenylation impacts protein trafficking and localization and increases proinflammatory cytokine production. Deficiency of the enzymes in the MVK pathway is known to cause systemic autoinflammatory diseases with a broad spectrum of clinical manifestations. Anticholesterol drug statins, which block the second enzyme in this pathway, HMG-CoA reductase, can lead to muscle inflammation. We report biallelic loss-of-function variants in the HMGCS1 gene, which encodes for the first enzyme in the MVK pathway, in four patients from three unrelated families who presented with recurrent fever, arthritis, abdominal pain, and progressive myositis. Three patients were homozygous for a rare variant, c.265C>T (p.Arg89Trp), predicted to be deleterious by multiple algorithms. One patient was homozygous for the novel c.572G>C (p.Arg191Pro) variant classified as VUS. The enzyme activity of both mutant HMGCS1 proteins was decreased, suggesting a deleterious effect on the protein function. Preliminary results showed that these missense variants do not affect protein expression or dimerization, which is critical for protein activity. The PBMCs from patients and CRISPR/cas9–edited HMGSC1-deficient cells showed a defect in prenylation, confirming the involvement of the MVK pathway. HMGCS1-deficient cells displayed an elevated level of IL-1β and IL-18 in response to stimulation with Pam3CSK4 and IFNγ, indicating that HMGCS1 deficiency led to inflammasome activation, which was independent of NLRP3 but was dependent on pyrin. UMAP analysis of peripheral blood single-cell RNA sequencing identified two major cell clusters: NK cells and monocytes. The most differentially upregulated pathways include oxygen/CO2 transport genes, cell death genes, and NF-κB signaling. Intracellular cytokine staining identified a significant increase of IL-1 β, IL-6, and IFNγ in all monocyte subsets of affected patients compared with unaffected relatives. RNA sequencing of frozen muscle tissues detected strong type I and II IFN signatures. Treatment with a JAK inhibitor ameliorated systemic and muscle inflammation in two patients. Further studies are in progress to understand the spectrum of immune dysregulation associated with the HMGCS1 deficiency.

Although ∼20% of early-onset colorectal cancer (EOCRC, age at diagnosis <50y) cases are due to germline mutations, the etiology of the majority of EOCRC cases remains poorly understood. EOCRC differs molecularly from late-onset colorectal cancer (LOCRC, age at diagnosis > 70y), with EOCRC tumors more frequently exhibiting high-grade histology, immune-related signatures, and microsatellite instability, while LOCRC is marked by DNA damage and oxidative stress pathways. Although consensus molecular subtypes (CMS) offer a framework for classification, they do not fully explain the rising EOCRC incidence, highlighting the need for integrative multiomic approaches to uncover underlying genetic, epigenetic, and environmental drivers for EOCRC. We leveraged genomic, transcriptomic, and clinical data from 1,135 sporadic microsatellite stable colorectal cancer (CRC) patients enrolled in the Total Cancer Care protocol and included in the Oncology Research Information Exchange Network (ORIEN) Avatar program across seven U.S. cancer centers, using standardized protocols for biospecimen collection, sequencing, and data harmonization. Whole exome sequencing (WES) and transcriptomic profiling (RNA-Seq) was conducted using standardized pipelines, followed by normalization and filtering. We characterized biological differences across EOCRC and LOCRC using differential expression, molecular subtyping, immune deconvolution, survival analysis, and integrated pathway analyses combining RNA-seq and WES data. Our cohort included 27.8% EOCRC, 53.5% average-onset (50-69y) and 18.9% LOCRC cases. EOCRC patients were more likely to present with rectal tumors (24% vs. 14%), advanced stage (75% vs. 57%), and receive treatments at a higher proportion (radiotherapy: 35% vs. 23%; adjuvant therapy: 51% vs. 37%) compared to LOCRC. No significant differences were observed in common CRC mutations or tumor mutational burden. EOCRC cases were significantly enriched for the mesenchymal CMS4 subtype and depleted in CMS2 and CMS3 (p < 9.46 × 10-6), though 5-year survival did not differ by CMS (p-value=0.23). Notably, we observed that EOCRC cases with CMS2 or CMS4 were more likely to be overweight (BMI >= 25kg/m2) as compared to LOCRC (OR > 2). Transcriptomic analysis identified 328 differentially expressed genes (306 up-regulated and 22 down-regulated in EOCRC); GSEA analysis showed enrichment of Hedgehog and calcium signaling pathways (FDR < 0.1) in EOCRC. This comparison of EOCRC and LOCRC cases demonstrates clear differences in CMS subtypes, reveals specific associations with environmental factors, and suggests that calcium channel signaling and hedgehog signaling may play a crucial role in the development and progression of EOCRC compared to LOCRC. Sheetal Hardikar, Griffin Caryotakis, David A. Nix, Aaron Atkinson, Jamie Teer, Vaia Florou, Andreana Holowatyj, Michelle L. Churchman, David M. McKean, Phaedra Agius, Bodour Salhia, Ning Jin, Daniel Spakowicz, Micha Cavnar, Emily Baiyee. Toegel, Tiago Biachi de Castria, Patrick M. Boland, Ahmad Tarhini, Bryan P. Schneider, Matthew Reilley, Deepak Vadehra, Michele M. Gage, Howard Colman, Courtney Scaife, Jessica N. Cohan, Biljana Gigic, Adetunji Toriola, Christopher I. Li, Jane Figueiredo, Dorotha Byrd, David Shibata, Cornelia M. Ulrich, Aik Choo Tan, Erin M. Siegel. Transcriptomic and pathway analyses patterns in early-onset and late-onset microsatellite stable colorectal cancer: Results from the ORIEN Network [abstract]. In: Proceedings of the AACR Special Conference in Cancer Research: The Rise in Early-Onset Cancers—Knowledge Gaps and Research Opportunities; 2025 Dec 10-13; Montreal, QC, Canada. Philadelphia (PA): AACR; Clin Cancer Res 2025;31(23_Suppl):Abstract nr PR012.