摘要：
Background. Hypoxia-inducible factor-1α (HIF-1α) is one of the pivotal mediators in the response of lungs to decreased oxygen availability, and increasingly has been implicated in the pathogenesis of pulmonary hypertension. Vascular endothelial growth factor (VEGF), a downstream target gene of HIF-1α, plays an important role in the pathogenesis of hypoxic pulmonary hypertension and hypoxic pulmonary artery remodelling. In this study, we investigated the dynamic expression of HIF-1α and VEGF in pulmonary artery of rats with hypoxia-induced pulmonary hypertension. Methods. Forty male Wistar rats were exposed to hypoxia for 0, 3, 7, 14 or 21 days. Mean pulmonary arterial pressure (mPAP), vessel morphometry and right ventricle hypertrophy index (RVHI) were estimated. Lungs were inflated and fixed for in situ hybridisation and immunohistochemistry. Results. mPAP values were significantly higher than the control values after 7 days of hypoxia [(18.4 ± 0.4) mmHg, P < 0.05]. RVHI developed significantly after 14 days of hypoxia. Expression of HIF-1α protein increased in pulmonary arterial tunica intima of all hypoxic rats. In pulmonary arterial tunica media, HIF-1α protein was markedly increased by day 3 (0.20 ± 0.02, P < 0.05), reached the peak by day 7, then declined after day 14 of hypoxia. HIF-1α mRNA increased significantly after day 14 of hypoxia (0.20 ± 0.02, P < 0.05). VEGF protein began to increase markedly after day 7 of hypoxia, reaching its peak around day 14 of hypoxia (0.15 ± 0.02, P < 0.05). VEGF mRNA began to increase after day 7 of hypoxia, then remained more or less stable from day 7 onwards. VEGF mRNA is located mainly in tunica intima and tunica media, whereas VEGF protein is located predominantly in tunica intima. Linear analysis showed that HIF-1α mRNA, VEGF and mPAP were correlated with hypoxic pulmonary artery remodelling. HIF-1α mRNA was positively correlated with VEGF mRNA and protein (P < 0.01). Conclusion. HIF-1α and VEGF are both involved in the pathogenesis of hypoxia-induced pulmonary hypertension in rats.
摘要：
Background. This study was designed to investigate the potential pathogenicity of Mycoplasma penetrans (M. penetrans) and its molecular mechanisms responsible for the induction of iNOS gene expression in mouse macrophages stimulated by lipid-associated membrane proteins (LAMPs) prepared from M. penetrans. Methods. Mouse macrophages were stimulated with M. penetrans LAMPs to assay the production of nitric oxide (NO). The expression of inducible nitric oxide synthase (iNOS) was detected by RT-PCR and Western blotting. The activity of nuclear factor κB (NF-κB) and the effects of pyrrolidine dithiocarbamate (PDTC), an inhibitor of NF-κB, on the production of nitric oxide and the expression of iNOS were also assessed in mouse macrophages treated with M. penetrans LAMPs by indirect immunofluorescence and Western blotting. Results. M. penetrans LAMPs stimulated mouse macrophages to produce nitric oxide in a dose- and time-dependent manner. The mRNA and protein levels of iNOS were also upregulated in response to LAMP stimulation and inhibited by PDTC treatment. M. penetrans LAMPs were found to trigger NF-κB activation, a possible mechanism for the induction of iNOS expression. Conclusion. This study demonstrated that M. penetrans may be an important etiological factor of certain diseases due to the ability of M. penetrans LAMPs to stimulate the expression of iNOS, which is probably mediated through the activation of NF-κB.
摘要：
Cholesterol-loaded macrophage foam cells are a central component of atherosclerotic lesions. ATP binding cassette transporter A1 (ABCA1), the defective molecule in Tangier disease, mediates the efflux of phospholipid and cholesterol from cells to apolipoprotein A-I (apoA-I), reversing foam cell formation. This study investigated the effect of apoA-I on ABCA1 degradation and cholesterol efflux in THP-1 macrophage-derived foam cells. After exposure of the cultured THP-1 macrophage-derived foam cells to apoA-I for different time, cholesterol efflux, ABCA1 mRNA and protein levels were determined by FJ-2107P type liquid scintillator, RT-PCR and Western blot, respectively. The mean ABCA1 fluorescence intensity on THP-1 macrophage-derived foam cells was detected by flow cytometry. Results showed that apoA-I markedly increased ABCA1-mediated cholesterol efflux from THP-1 macrophage-derived foam cells. This was accompanied by an increase in the content of ABCA1. ApoA-I did not alter ABCA1 mRNA abundance. Significantly, thiol protease inhibitors increased the level of ABCA1 protein and slowed its decay in THP-1 macrophage-derived foam cells, whereas none of the proteosome-specific inhibitor lactacystin, other protease inhibitors, or the lysosomal inhibitor NH4Cl showed such effects. The apoA-I-mediated cellular cholesterol efflux was enhanced by thiol protease inhibitors. Our results suggested that thiol protease inhibitors might provide an alternative way to upregulate ABCA1 protein. This strategy is especially appealing since it may mimic the stabilizing effect of the natural ligands apoA-I.
摘要：
Background. Daxx has been identified as a nuclear protein that involves in apoptosis and transcriptional repression. Daxx co-localizes with the promyelocytic leukemia (PML) protein and regulates transcription. Human Daxx (hDaxx) is a protein that functions as a transcriptional regulation through its interaction with some DNA-associated proteins. The aim of this study was to explore the transcriptional regulatory effect of hDaxx interacting with adenovirus (Ad) 12 E1B (Ad12E1B) 55-kDa oncoprotein. Methods. The co-localization of hDaxx-Ad12E1B or hDaxx-PML protein in the nucleus was observed under a confocal microscope. Interaction of hDaxx and Ad12E1B was analyzed by yeast two-hybrid assay. Direct binding of hDaxx and Ad12E1B was analyzed using coimmunoprecipitation and Western blot in vivo and in vitro. The activity of a luciferase reporter gene, which was regulated by an hDaxx modulated thymidine kinase (TK) promoter, was detected in an automat luminometer. Results. Ad12E1B, which co-localized with hDaxx in the nuclei of G401-CC3 cells, disrupted the co-localization of hDaxx and PML in the PML oncogenic domains (PODs). hDaxx bound directly to Ad12E1B in vivo and in vitro. hDaxx interacted with Ad12E1B along its full length. Ad12E1B enhanced transcriptional repression activity of hDaxx. Conclusion. Ad12E1B disrupts the co-localization of hDaxx with PML in PODs and enhances transcriptional repression activity of hDaxx.
作者机构：
[Yang, J. H.; Sun, W. Q.; Wan, Z. Y.; Yang, B. T.; Wang, S.; Yang, Y. Z.; Liu, L. S.; Yi, G. H.; Tang, C. K.; Wang, Z.; Ruan, C. G.; Feng, D. M.] Nanhua Univ, Inst Cardiovasc Res, Hengyang, Hunan, Peoples R China.
作者机构：
[Yang, J. H.; Yang, Y. Z.; Tang, C. K.; Yil, G. H.; Yan, Wan; Mo, Z. C.] Nanhua Univ, Inst Cardiovasc Res, Hengyang, Peoples R China.;[Xi, S. M.; Wang, Z. B.; Yin, W. D.] Nanhua Univ, Sch Life Sci & Technol, Dept Biochem & Mol Biol, Hengyang, Peoples R China.
摘要：
AIM: To study the effect of oxidized low density lipoprotein (ox-LDL) on ATP binding cassette transporter A1 (ABCA1) in THP-1 macrophages. METHODS: After exposing the cultured THP-1 macrophages to ox-LDL for different periods, cholesterol efflux was determined by FJ-2107P type liquid scintillator. ABCA1 mRNA and protein level were determined by reverse trancriptase-polymerase chain reaction (RT-PCR) and Western blot, respectively. The cholesterol level in THP-1 macrophage foam cells was detected by high performance liquid chromatography. RESULTS: ox-LDL elevated ABCA1 in both protein and mRNA levels and increased apolipoprotein (apo) A-I-mediated cholesterol efflux in a time- and dose-dependent manner. 22(R)-hydroxycholesterol and 9-cis-retinoic acid did significantly increase cholesterol efflux in THP-1 macrophage foam cells (P<0.05), respectively. Both of them further promoted cholesterol efflux (P<0.01). As expected, liver X receptor (LXR) agonist decreased content of esterified cholesterol in the macrophage foam cells compared with control, whereas only a slight decrease of free cholesterol was observed. LXR activity was slightly increased by oxidized LDL by 12 % at 12 h compared with 6 h. However, LXR activity was increased about 1.8 times at 24 h, and oxidized LDL further increased LXR activity by about 2.6 times at 48 h. CONCLUSION: ABCA1 gene expression was markedly increased in cholesterol-loaded cells as a result of activation of LXR/RXR. ABCA1 plays an important role in the homeostasis of cholesterol in the macrophages.
摘要：
AIM: To investigate the reversal effect of neferine on multidrug resistance in human gastric carcinoma cell line. METHODS: Cells of a human gastric cancer cells line, SGC7901, and its vincristine (VCR) -resistant variant, SGC7901/VCR, were cultivated with or without neferine and/or VCR. The cytotoxic effect of VCR was evaluated by the MTT assay. Cell apoptosis induced by VCR was determined by flow cytometry (FCM). The expression of P-glycoprotein (P-gp) and a multidrug-resistance-associated protein (MRP) in cells was examined by immunofluorescence and FCM. RESULTS: Neferine at the concentration from 2.5 micromol/L to 10 micromol/L had no cytotoxicity to SGC7901 cells, and its variant SGC7901/VCR cells. The IC50 of VCR against SGC7901 and SGC7901/VCR cells was 0.059 microg/mL and 2.32 microg/mL, respectively, indicating that SGC7901/VCR cells were 39 times more resistant to VCR than its parent SGC7901 cells. After treatment with neferine at concentrations of 2.5, 5 and 10 micromol/L, the IC(50) of VCR to SGC7901/VCR cell line decreased to 0.340, 0.128 and 0.053 microg/mL, respectively, thus, increased the chemosensitivity by 6.8-, 18.1- and 43.8-fold, respectively. SGC7901/VCR cells were apoptosis resistant to VCR. Neferine (2.5, 5 and 10 micromol/L) promoted the VCR-induced apoptosis of SGC7901/VCR cells in a dose-dependent manner. The expressions of P-gp and MRP were strongly positive in SGC7901/VCR cells, which were significantly down-regulated after treatment with neferine (10 micromol/L) for 24 h. CONCLUSION: Neferine reverses multidrug resistance of human gastric carcinoma SGC7901/VCR cells, which may be associated with the down-regulations of P-gp and MRP expression in SGC701/VCR cells.
期刊：
DRUGS OF THE FUTURE,2004年29(1):53-62 ISSN：0377-8282
通讯作者：
Yin, W
作者机构：
[Yin, W] Nanhua Univ, Dept Biochem & Mol Biol, Sch Life Sci & Technol, Hengyang 421001, Peoples R China.;Nanhua Univ, Cardiovasc Res Inst, Sch Med, Hengyang 421001, Peoples R China.;Otsuka Pharmaceut Factory Inc, Res & Dev, Naruto, Tokushima 7728601, Japan.
通讯机构：
[Yin, W] N;Nanhua Univ, Dept Biochem & Mol Biol, Sch Life Sci & Technol, Hengyang 421001, Peoples R China.
摘要：
Lipoprotein lipase (LPL) is a rate-limiting enzyme that hydrolyzes circulating triglyceride (TG)-rich lipoproteins such as very low-density lipoproteins (VLDL) and chylomicrons. A decrease in LPL activity is associated with an increase in plasma TG and a decrease in plasma high-density lipoprotein cholesterol (HDL-C). The increase in plasma TG and decrease in plasma HDL-C are risk factors for cardiovascular disease (CVD). Tsutsumi et al. hypothesized that elevating LPL activity would cause a reduction in plasma TG and an increase in plasma HDL-C, resulting in protection against the development of atherosclerosis. To test this hypothesis, Otsuka synthesized the LPL activator NO-1886. The effects of NO-1886 in animals have been extensively studied. NO-1886 has been shown to increase LPL mRNA and LPL activity in adipose tissue, myocardium and skeletal muscle, resulting in an elevation of post-heparin plasma LPL activity and LPL mass in rats. NO-1886 has also been shown to decrease plasma TG concentration and to cause a concomitant rise in plasma HDL-C. Long-term administration of NO-1886 to rats and rabbits with experimental atherosclerosis inhibited the development of atherosclerotic lesions in coronary arteries and aorta. The results of multiple regression analysis in these studies suggested that the increase in plasma HDL-C and the decrease in plasma TG protected against atherosclerosis. These results show that the atherogenic lipid profile is changed to an antiatherogenic lipid profile by increasing LPL activity, resulting in protection against the development of atherosclerosis. Therefore, the LPL activator NO-1886 is potentially beneficial for the treatment of hypertriglyceridemia and hypo-HDL-cholesterolemia, and for protection against atherosclerosis. Furthermore, we hypothesized that elevation of LPL activity in adipose tissue would cause an improvement in cachexia, and elevation of LPL activity in skeletal muscle would lead to an improvement in obesity, because the LPL in adipose tissue is related to fat storage and LPL in skeletal muscle is related to free fatty acid (FFA) oxidation. From the many published studies, we confirmed that NO-1886 improved cachexia by elevating LPL activity in adipose tissue and improved obesity by elevating LPL activity in skeletal muscle. It is concluded that NO-1886, and possibly other LPL-activating agents, protect against atherosclerosis, as well as cachexia and obesity.
