{"database":"GEO","file_versions":[{"headers":{"Content-Type":["application/json"]},"body":{"files":{"Other":["ftp://ftp.ncbi.nlm.nih.gov/geo/series/GSE285nnn/GSE285911/"]},"type":"primary"},"statusCode":"OK","statusCodeValue":200}],"scores":null,"additional":{"omics_type":["Transcriptomics"],"species":["Mus musculus"],"gds_type":["Expression profiling by high throughput sequencing"],"full_dataset_link":["https://www.ncbi.nlm.nih.gov/geo/query/acc.cgi?acc=GSE285911"],"repository":["GEO"],"entry_type":["GSE"],"additional_accession":[]},"is_claimable":false,"name":"Inherited Variant in MRC2 Causes Cardiac Fibroblast Dysfunction and Increases Atrial Fibrillation Susceptibility","description":"Background. A recent study identified a rare variant in the MRC2 gene in individuals with familial reentrant supraventricular tachycardia, a Wolff-Parkinson-White (WPW) ECG pattern, and structurally normal hearts. WPW syndrome is associated with atrial fibrillation (AF), and MRC2 was recently proposed as a protective gene for AF. Objective. We aimed to determine whether the E990G-heterozygous (het) loss-of-function variant in MRC2 increases AF susceptibility and aberrant atrial cardiofibroblast (ACF) function in mice. Methods. Programmed electrical stimulation (PES) was performed to determine AF susceptibility in E990G-het mice and wild-type (WT) controls. ACFs were isolated from these mice and cultured, and their migration, and collagen deposition were quantified. Finally, transcriptomic profiling by RNA sequencing and secretomic/proteomic profiling by mass spectrometry were performed on ACFs and whole atrial tissue. Results. E990G-het mice exhibited increased susceptibility to pacing-induced AF and had decreased atrioventricular effective refractory periods compared to WT controls. ACFs isolated from E990G-het mice deposited greater amounts of acid-soluble collagen in 2D cultures as quantified by Sirius red staining compared with WT controls. Transcriptomic, secretomic, and proteomic profiling of cultured ACFs and whole-atrial tissue suggest that some fibrotic regulators are differentially expressed or secreted, including decreased ACF expression of matrix metalloproteinase 13 (MMP-13), which degrades collagen types I, II, and III; decreased ACF expression, ACF secretion, and atrial tissue levels of matrix metalloproteinase 12 (MMP-12), which degrades collagen types I, III, IV, elastin, and fibronectin; and increased tissue levels of cellular communication network factor 2/connective tissue growth factor (CCN2/CTGF), a profibrotic regulator. Conclusions. MRC2 E990G-het mice exhibit increased AF susceptibility, altered collagen deposition by ACFs, and differentially regulated fibrotic genes and proteins. Together, these findings suggest that excessive collagen deposition and reduced MMP-mediated collagen removal generate a substrate for the development of AF in the presence of a loss-of-function variant in MRC2.","dates":{"publication":"2026/06/01"},"accession":"GSE285911","cross_references":{"GSM":["GSM8712449","GSM8712447","GSM8712448","GSM8712445","GSM8712446"],"GPL":["24247"],"GSE":["285911"],"taxon":["Mus musculus"]}}