A 3D Mitral Valve Interstitial Cell Model Recapitulates Selected Transcriptomic Signatures of Degenerative Mitral Valve Disease

Degenerative mitral valve disease (DMVD) is a highly prevalent cardiovascular disorder in humans, dogs and pigs. However, the molecular mechanisms driving mitral valve interstitial cell (VIC) activation and extracellular matrix (ECM) remodeling remain incompletely understood. In this study, we established a three-dimensional (3D) VIC-collagen model (VIC-COL) to investigate the cellular changes of VIC activation and ECM remodeling in response to transforming growth factor-β1 (TGF-β1) stimulation. The results revealed that upregulation of α-smooth muscle actin (α-SMA), fibronectin and matrix metalloproteinase 2 (MMP2) was induced by TGF-β1 in the VIC-COL model; subsequent transcriptomic profiling identified a significant phenotypic shift toward pro-inflammatory and matrix remodeling pathways. Crucially, comparative transcriptomic analysis with naturally occurred DMVD public datasets identified 120 shared Gene Ontology (GO) biological process pathways and 111 conserved differentially expressed genes. Kyoto Encyclopedia of Genes and Genomes (KEGG) pathway analysis confirmed that TGF-β1 treatment in the porcine in vitro model recapitulates a subset of the transcriptional features of DMVD, including the cell adhesion molecules, ECM-receptor interactions, tumor necrosis factor (TNF) signaling and cytokine-cytokine receptor interactions. Gene Set Enrichment Analysis (GSEA) further corroborated concordant Hallmark inflammatory signatures, including TNF-α signaling via nuclear factor-kappa B (NF-κB), and interleukin-6/Janus kinase/signal transducer and activator of transcription 3 (IL-6/JAK/STAT3) signaling. These shared transcriptomic features indicate that TGF-β1 stimulation captures certain molecular aspects of ECM remodeling, VIC activation, and inflammatory-related signaling seen in naturally occurring DMVD. Collectively, the 3D VIC-COL system provides a reproducible in vitro platform for investigating selected molecular mechanisms of DMVD.