Li Muyao, Mossman Brooke T, Kolpa Emily, Timblin Cynthia R, Shukla Arti, Taatjes Douglas J, Fukagawa Naomi K
Department of Medicine, University of Vermont College of Medicine, Burlington, Vermont 05405, USA.
J Cell Physiol. 2003 Dec;197(3):418-25. doi: 10.1002/jcp.10384.
Aortic vascular smooth muscle cells (VSMC) were used to study the effect of age on responses to high glucose concentrations or the cytokine, tumor necrosis factor-alpha (TNF-alpha). Activator protein-1 (AP-1) binding to DNA increased more in VSMC from old versus young rats (P < 0.02) and was related to increased expression of its components, c-Fos, Fra-1, and JunD. The relationship to upstream signals, i.e., activities of mitogen-activated protein kinases (MAPK), was studied using antibodies to total and phosphorylated forms of extracellular signal-regulated kinases (ERK), c-Jun N-terminal kinases (JNK) and p38. High glucose and TNF-alpha increased ERK phosphorylation more in old (P < 0.05); whereas only TNF-alpha induced JNK activation in young (P < 0.04). PD98059, a MEK inhibitor, attenuated AP-1 activation, lowered c-Fos and Fra-1 protein levels and reduced cell number and cells positive for proliferating cell nuclear antigen in old. We concluded that age differentially influenced activation of signaling pathways in VSMC exposed to high glucose or TNF-alpha. This may contribute to the increased risk for vascular disease associated with aging and diabetes mellitus (DM).
主动脉血管平滑肌细胞（VSMC）被用于研究年龄对高葡萄糖浓度或细胞因子肿瘤坏死因子-α（TNF-α）反应的影响。与年轻大鼠相比，老年大鼠VSMC中与DNA结合的激活蛋白-1（AP-1）增加更多（P<0.02），且与其成分c-Fos、Fra-1和JunD的表达增加有关。使用针对细胞外信号调节激酶（ERK）、c-Jun氨基末端激酶（JNK）和p38的总形式和磷酸化形式的抗体，研究了与上游信号（即丝裂原活化蛋白激酶（MAPK）的活性）的关系。高葡萄糖和TNF-α在老年大鼠中使ERK磷酸化增加更多（P<0.05）；而仅TNF-α在年轻大鼠中诱导JNK激活（P<0.04）。MEK抑制剂PD98059减弱了老年大鼠的AP-1激活，降低了c-Fos和Fra-1蛋白水平，并减少了细胞数量和增殖细胞核抗原阳性细胞。我们得出结论，年龄对暴露于高葡萄糖或TNF-α的VSMC中信号通路的激活有不同影响。这可能导致与衰老和糖尿病（DM）相关的血管疾病风险增加。
