OBJECTIVETo observe whether CD137 signaling could affect the nuclear factor of activated T cells c1 (NFATc1) expression through nuclear factor-κB (NF-κB) pathway in mice aortic vascular smooth muscle cells (VSMCs).

METHODSAdherence methods for tissues explants were used for primary culture of mouse aortic VSMCs. The mRNA expression of CD137 and NFATc1 was detected by real-time quantitative PCR (RT-qPCR). The VSMCs protein expression of IκB-α, NF-κB p65, phospo-p65 and NFATc1 was determined by Western blot. The level of CD137 was measured by Flow Cytometry (FCM).

RESULTS(1) The mRNA and protein expression of CD137 in VSMCs was significantly upregulated at 24 h after co-culture with TNF-α (10 ng/ml, all P < 0.05). (2) Compared with the control group, the level of p-NF-κB p65 in cytoplasm and nucleus was significantly increased (8.34 ± 0.28 vs. 1, P < 0.05, and 2.64 ± 0.42 vs. 1, P < 0.05) while the level of IκB-α was reduced (1 vs. 2.70 ± 0.28, P < 0.05) after co-treatment with agonist-CD137 mAb, above effects were partly blocked by adding specific NF-κB inhibitor PDTC (30 µmol/L: 1.15 ± 0.14 vs. 8.34 ± 0.28, P < 0.05, and 2.09 ± 0.12 vs. 2.64 ± 0.42, P < 0.05, and 1.78 ± 0.74 vs. 1, P < 0.05). (3) The mRNA (2.07 ± 0.09 vs. 1, P < 0.05) and protein (1.75 ± 0.07 vs. 1, P < 0.05) expression of NFATc1 was significantly upregulated by agonist CD137mAb compared with the control group, and these effects could be reversed by PDTC (1.15 ± 0.07 vs. 2.07 ± 0.09, P < 0.05, and 0.90 ± 0.11 vs. 1.75 ± 0.07, P < 0.05).

CONCLUSIONCD137 signaling could affect the NFATc1expression in VSMCs through NF-kappaB pathway.