Objective  To analyze the influences of different concentrations of homocysteine (Hcy) mediated protein kinase C (PKC)/mitogen-activated protein kinase (MAPK)/signal transducer in vitro and activator of transcription 1 (STAT1) signaling pathway on the expression of cathepsin V (CTSV) and inflammatory factors in human coronary endothelial cells (HCAECs).

  Methods  The experiment was divided into four groupscontrol group (normal saline), low-concentration (Hcy 1 mmol/L), medium-concentration (5 mmol/L) and high-concentration (10 mmol/L) groups. They were co-cultured with HCAECs at four concentrations for 72 hours. The cell viability was detected by May-Thurner syndrome (MTS), the relative expression of PKC, MAPK, STAT1 and CTSV were detected by western blot, and inflammatory factors including vascular endothelial growth factor receptor-1 (VEGFR-1), tumor necrosis factor-α(TNF-α) and interleukin-1 β (IL-1 β) were detected by enzyme-linked immunosorbent assay.

  Results  Compared with the control group and low-concentration group, the cell viability was increased, relative expression of PKC, MAPK, STAT1 and CTSV were increased, the expression levels of VEGFR-1, TNF- α and IL-1 β were significantly increased in the medium and high-concentration group(P<0.05). The relative expression of PKC, MAPK, STAT1 and CTSV, the expression levels of VEGFR-1, TNF-α and IL-1 β and the cell viability in the high-concentration group were significantly higher than those in the medium-concentration group (P<0.05), while there were no differences between the control group and the low-concentration group in above indicators (P>0.05).

  Conclusion  The increase of Hcy concentration can activate PKC/MAPK/STAT1 signal pathway in HCAECs and affect the expression of CTSV and inflammatory factors with a concentration-dependent manner. High expression of Hcy is closely related to coronary artery injury caused by Kawasaki disease, which provides an important target for clinical intervention.