[Homocysteine induces macrophage inflammatory protein-1alpha expression by activating NF-kappaB in THP-1 monocytes].

OBJECTIVE: To investigate the effect of homocysteine (HCY) on activation of nuclear factor (NF-kappaB) and inhibitory factor IkappaB-alpha in human monocyte cell line THP-1, as well as its association with macrophage inflammatory protein (MIP-1alpha) upregulation. METHODS: THP-1 monocytes were incubated with HCY, with and without NF-kappaB inhibitor pyrolidine dithiocarbamate (PDTC) pretreatment. Northern blot analysis and flow cytometry were used to detect MIP-1alpha mRNA and protein respectively. The nuclear protein NF-kappaB P65 subunit and the inhibitory protein IkappaB-alpha were analyzed by Western blotting. RESULTS: Compared with controls, HCY, at a concentration of 0.1 mmol/L, was able to enhance the expression of MIP-1alpha mRNA (up to 3.69-fold) and protein (1.16-fold) in THP-1 monocytes, as well as enhance NF-kappaB P65 transcription to nuclear proteins. These actions were significantly suppressed after pretreatment with 100 micromol/L PDTC for 30 minutes before HCY incubation; whereas incubation of THP-1 monocytes with PDTC only had no effect on both the expression of MIP-1alpha and nuclear transcription of NF-kappaB P65. Moreover, the level of IkappaB-alpha protein in THP-1 monocytes decreased after a 30-minute incubation with HCY, which gradually increased after 120 minutes. CONCLUSIONS: Homocysteine at a pathologic concentration stimulates MIP-1alpha expression in THP-1 monocytes, probably via NF-kappaB activation. Such activation may be caused by enhanced phosphorylation and degradation of the inhibitor protein IkappaB-alpha.

[Study on effect of anisodamine on expressions of tissue factor and plasminogen activator-1 inhibitor in vascular endothelial cells and its mechanisms].

OBJECTIVE: To explore the mechanism of anisodamine in treating infectious shock through studying effect of anisodamine on endotoxin lipopolysaccharide (LPS) induced expression of tissue factor (TF) and plasminogen activator inhibitor type 1 (PAI-1) in vascular endothelial cells (EC). METHODS: Human umbilical vein endothelial cells (HUVEC) were cultured by trypsin digestion method. PAI-1 was measured in the conditioned medium of HUVEC by a specific enzyme-linked immunosorbent assay (ELISA), whereas TF activity was measured in the lysates of these cells by using a single step clotting assay. Specific mRNA expressions were determined by Northern blotting. In order to evaluate a possible contribution of the nuclear factor-kappa B (NF-kappa B) pathway on the transductive effects observed, electrophoretic mobility shift assays (EMSA) were performed using nuclear extracts from HUVEC and NF-kappa B binding oligonucleotides. RESULTS: LPS could significantly strengthen the expression of HUVEC PAI-1 protein and TF activity and its mRNA, this effect of LPS could be markedly weakened after adding Anisodamine dose-dependently. Anisodamine could also completely block the LPS induced NF-kappa B DNA binding activity in nuclear extracts from HUVEC. CONCLUSION: The possible mechanism of anisodamine in treating infectious shock may be through antagonizing LPS induced HUVEC TF and PAI-1 expression, and the antagonism might be, at least partially, transduced by path of NF-kappa B.

[Lipopolysaccharide induces expression of macrophage inflammatory protein-1alpha in human umbilical vein endothelial cells].

OBJECTIVE: To understand whether endotoxin lipopolysaccharide (LPS) is able to induce the expression of macrophage inflammatory protein-1alpha (MIP-1alpha) mRNA and protein in human umbilical vein endothelial cells (HUVECs). METHODS: The expression of MIP-1alpha mRNA was determined by dot blotting analysis and by in situ hybridization using a digoxigenin-labeled MIP-1alpha cDNA probe after exposure of the cultured HUVECs to LPS at different concentrations. The expression of MIP-1alpha mRNA was determined by RT-PCR as well. In addition, the expression of MIP-1alpha protein was tested by cell enzyme-linked immunosorbent assay (ELISA) using a goat anti-human monoclonal MIP-1alpha antibody. RESULTS: Dot blotting showed that the absorbance values of the dots on the nitrocellulose membrane were 1.490 and 3.310 when exposed to LPS at the concentrations of 1 micro g/ml and 10 micro g/ml which were 1.97- and 4.38-fold over that of the control group (0.775), respectively. In situ hybridization revealed that exposure to LPS at a concentration of 1 micro g/ml led to a significant increase in the MIP-1alpha mRNA expression in HUVECs as compared to the control group (F = 142.83, P < 0.01), whereas the MIP-1alpha mRNA in HUVECs was somewhat decreased when exposed to LPS at a concentration of 10 micro g/ml. RT-PCR revealed that the expression of MIP-1alpha mRNA in HUVECs were 1.65-, 2.86- and 1.26-fold over that of the control group when exposed to LPS at the concentrations of 1 micro g/ml, 5 micro g/ml and 10 micro g/ml respectively. Cell ELISA showed that after exposure of the HUVECs to LPS at the concentrations mentioned above, the expression of MIP-1alpha protein was strongly increased, especially in the 5 micro g/ml LPS group. Analysis of variance showed that there was a significant difference between groups (F = 15.36, P < 0.05). CONCLUSIONS: LPS may induce a high level of MIP-1alpha mRNA and protein expression in HUVECs, and it might, hereby, play an important role in the recruitment of the monocytes/macrophages into the arterial intima.