Background <p>Cardiac fibroblasts play a key role in extracellular matrix (ECM) remodelling through the synthesis of glycosaminoglycans and proteoglycans (PGs), such as decorin; however, the effects of kisspeptin-10 (KiSS-10) on these components in the heart remain unknown. The aim of this study was to determine the influence of KiSS-10 on glycosaminoglycan and decorin content in human cardiac fibroblast cultures and identify its mechanism.</p> Methods <p>The effects of KiSS-10 on glycosaminoglycans and decorin were assessed in human cardiac fibroblast cell line, with or without signalling inhibitor. Glycosaminoglycan levels were determined by the Farndale method, decorin secretion by enzyme-linked immunosorbent assay (ELISA), and decorin expression by quantitative polymerase chain reaction (qPCR).</p> Results <p>KiSS-10 treatment caused a dose-dependent increase in glycosaminoglycan content in both cells and medium. This stimulatory effect was abolished by blocking G-protein–coupled receptor 54 (GPR54) with peptide 234 or focal adhesion kinase (FAK) with FAK inhibitor 14 (FAKi). Combining KiSS-10 with phospholipase C inhibitor (D609) did not alter the glycosaminoglycan level compared to KiSS-10 alone. KiSS-10 increased decorin secretion but not expression. Combining peptide 234 with KiSS-10 did not alter media decorin level compared to KiSS-10 alone.</p> Conclusions <p>KiSS-10 significantly elevated glycosaminoglycan and decorin accumulation in human cardiac fibroblast cultures. This regulatory effect on glycosaminoglycan level appears to be dependent on GPR54 activation and FAK signalling, but not on phospholipase C function. Hence, KiSS-10 may be involved in ECM remodelling in the heart.</p>