Age-related changes in matrix metalloproteinase-9 regulation in cultured mouse aortic smooth muscle cells.
We previously reported that aortic smooth muscle cells (SMC) from aged mice have an age-related decline in proliferative capacity compared with those derived from young mice. Here we investigated matrix metalloproteinase-9 (MMP-9) regulation in both young and aged SMC. Zymography, immunoblot, and northern blot analysis showed that MMP-9 expression is significantly reduced in response to tumor necrosis factor-alpha stimulation with increasing in vitro age. Mutational analysis, gel shift assays and supershift assays demonstrated that the lower MMP-9 expression in aged SMC is associated with lower activities of NF-kappaB and AP-1. Since mitogen-activated protein kinase ERK1/2 induce MMP-9 expression, we examined whether U0126, an ERK1/2 inhibitor, influenced MMP-9 expression in aged SMC. Treatment with U0126 successfully inhibited MMP-9 expression in both young and aged SMC. Finally, to analyze the causal relationship between replicative senescence and MMP-9 expression, we stably overexpressed the MMP-9 gene in aged SMC and we showed no alteration of the proliferative capacity of the transduced cells. Taken together, these results suggest that down-regulation of MMP-9 expression in SMC may play a role in vascular remodeling during in vitro aging.
Moon
Sung-Kwon
SK
National Research Laboratory for Glycobiology, Korean Ministry of Science and Technology, Kyungju, Kyungbuk 780-714, South Korea.
Cha
Byung-Yoon
BY
Lee
Young-Choon
YC
Nam
Kyung-Soo
KS
Runge
Marschall S
MS
Patterson
Cam
C
Kim
Cheorl-Ho
CH
D000375:Aging / Q000502:physiology*; D000818:Animals; D001011:Aorta; D015152:Blotting, Northern / Q000379:methods; D002455:Cell Division; D002478:Cells, Cultured; D004591:Electrophoresis, Polyacrylamide Gel / Q000379:methods; D015870:Gene Expression; D015151:Immunoblotting / Q000379:methods; D008297:Male; D020780:Matrix Metalloproteinase 9 / Q000032:analysis / Q000235:genetics / Q000378:metabolism*; D051379:Mice; D009130:Muscle, Smooth / Q000201:enzymology*; D016328:NF-kappa B / Q000032:analysis / Q000378:metabolism; D011401:Promoter Regions, Genetic; D018808:Transcription Factor AP-1 / Q000032:analysis / Q000378:metabolism; D014161:Transduction, Genetic / Q000379:methods; D014409:Tumor Necrosis Factor-alpha / Q000494:pharmacology
D016328:NF-kappa B; D018808:Transcription Factor AP-1; D014409:Tumor Necrosis Factor-alpha; D020780:Matrix Metalloproteinase 9