ROS-mediated downregulation of MYPT1 in smooth muscle cells: a potential mechanism for the aberrant contractility in atherosclerosis.

Reactive oxygen species (ROS) mediates the aberrant contractility in hypertension. Abnormal contractility occurs in atherosclerotic vessels but changes in proteins that regulate contractility remain poorly understood. Myosin phosphatase (MP) activity, which regulates smooth muscle relaxation, is regulated by the phosphorylation of its regulatory subunit, MP targeting subunit 1 (MYPT1). In the present study, we examined the roles of ROS in MP subunit expression both in cultured human aortic smooth muscle cells (HASMCs) and during atherosclerosis progression in apolipoprotein E-knockout (apoE-KO) mice. Furthermore, the effect of decreased MYPT1 on actin cytoskeleton and cell migration activity was assessed in HASMCs. Short hairpin RNA-mediated knockdown of MYPT1 increased stress fibers and attenuated platelet-derived growth factor-induced cell migration in HASMCs. Superoxide anion-inducing agent LY83583 downregulated MYPT1 mRNA and protein levels, but did not affect the phosphorylation of MYPT1 and catalytic subunit of MP, PP1δ. The LY83583-induced decrease in MYPT1 was abolished by co-treating with superoxide dismutase or by inhibiting NADPH oxidase with diphenyleneiodonium. Treatment of peroxynitrite, but not hydrogen peroxide (H2O2), downregulated MYPT1 protein expression and induced MYPT1 phosphorylation without affecting mRNA levels. Co-treatment with a proteasome inhibitor, MG-132, eliminated peroxynitrite-induced MYPT1 downregulation. In apoE-KO mice, MYPT1 protein, but not mRNA, levels were markedly decreased in 16-week- and 24-week-old mice. Oral estrogen treatment, which was previously shown to decrease aortic ROS levels, upregulated aortic MYPT1 expression. Moreover, reduction in MYPT1 expression correlated with increased aortic sensitivity toward vasoconstrictors. These results suggested that during atherosclerosis progression oxidative stress mediates the downregulation of MYPT1, which may inhibit smooth muscle cell migration and contribute to the aberrant contractility.

Costs of cervical cancer and precancerous lesions treatment in a publicly financed health care system.

PURPOSE: Although cervical cancer is the most frequent cancer for women in Taiwan, no examination of its treatment costs has yet been undertaken. This study aimed to investigate the costs of cervical cancer and precancerous lesion treatment in Taiwan. METHODS: A total of 7,398 cases of cervical intraepithelial neoplasia (CIN) lesions were identified from the Taiwan Cervical Cancer Screening Registration System in 2003. A further 1,469 cases of invasive cervical cancer (ICC) were also identified from a survey on cervical cancer staging information conducted by the Taiwan Cancer Registration Task Force. Resource usage covering the first 6 months after CIN diagnosis and the 5 years after ICC diagnosis were extracted from the National Health Insurance claims database. The duration of each visit and the transportation costs were collected by means of personal interviews with CIN/ICC patients. The mean and standard deviation of the treatment and indirect costs were estimated. RESULTS: The average total costs for CIN patients were NT$4,201 for CIN1, NT$8,623 for CIN2 and NT$14,406 for CIN3, with the indirect costs accounting for 25-33% of the total. The total costs for ICC patients were NT$210,230 for Stage 1, NT$392,387 for Stage 2, NT$433,969 for Stage 3 and NT$464,701 for Stage 4, with the indirect costs accounting for about 14-17% of the total. CONCLUSIONS: CIN and ICC treatment resulted in considerable costs to the healthcare system in Taiwan. Indirect costs associated with such treatment were also substantial and cannot be ignored.