Matrix metalloproteinase-3 (MMP3) in non-syndromic cleft lip and palate: extracellular matrix remodeling, developmental signaling, and molecular mechanisms.

Non-syndromic cleft lip and/or palate is one of the most common congenital craniofacial malformations and results from disruptions in tightly regulated developmental processes during early embryogenesis. Although non-syndromic cleft lip and/or palate has been primarily investigated through key developmental regulators, growing evidence indicates that EMC remodeling represents a critical and underexplored layer of disease susceptibility. Matrix metalloproteinase-3 (MMP3), zinc-dependent endopeptidase with broad substrate specificity and regulatory capacity, has repeatedly emerged as a candidate gene in genetic association studies of NSCL/P. This review integrates genetic, molecular, and systems-level evidence linking MMP3 to craniofacial development and non-syndromic cleft lip and/or palate pathogenesis. We summarize the structural features, regulatory mechanisms, and biological functions of MMP3, highlighting its role in controlled ECM remodeling and signal modulation. Genetic studies across multiple populations consistently implicate functional MMP3 promoter polymorphisms in non-syndromic cleft lip and/or palate susceptibility, with experimental data demonstrating their effects on transcriptional activity. Such regulatory variation provides a biologically plausible mechanism by which subtle changes in MMP3 expression during critical developmental windows may impair tissue fusion. Moving beyond isolated associations, protein-protein interaction and network-based analyses position MMP3 at the interface between ECM remodeling pathways and canonical developmental signaling networks, including TGF-β and epidermal growth factor-related pathways. This systems-level perspective supports a model in which MMP3 functions as a molecular integrator linking extracellular dynamics to developmental programs. These insights advance a refined molecular framework for understanding non-syndromic cleft lip and/or palate as a network-based developmental disorder.