Fibroblast growth factor 16: Molecular mechanisms, signalling crosstalk, and emerging roles in cardiac biology and metabolic regulation.

Fibroblast growth factor (FGF) 16 is critically involved in embryonic heart development, adult cardiac homeostasis, and potentially in metabolic regulation. Initially recognized for its cardiac-specific role during embryogenesis, recent studies demonstrate that FGF16 significantly mitigates pathological cardiac remodelling, such as fibrosis and hypertrophy, through competitive inhibition of FGF2-induced transforming growth factor-β1 signalling via FGF receptor 1c. Molecular investigations further indicate that FGF16 exerts cardioprotective effects primarily through activation of key intracellular pathways, including phosphoinositide 3-kinase/protein kinase B and protein kinase C, as well as regulation by transcription factors GATA binding protein 4, nuclear Factor kappa-light-chain-enhancer of activated B cells, and cardiac-specific homeobox/NK2 homeobox 5, and RNA methyltransferase-mediated N6-methyladenosine modifications. However, detailed mechanisms underlying receptor-specific interactions remain unclear. This review systematically summarizes the genomic organization, receptor selectivity, cardiac signalling mechanisms, and emerging metabolic roles of FGF16, critically evaluates the current evidence, identifies key research gaps, and highlights therapeutic potentials for cardiovascular and metabolic disorders.