[Impact and potential mechanism of human α-defensin 1 on low-density lipoprotein oxidation ability of ECV304 cells].

OBJECTIVE: To explore the role and potential mechanism of human α-defensin 1 (HNP-1) on low-density lipoprotein (LDL) oxidation ability of human endothelial cells (EVC304). METHODS: Post incubation with LDL for 3 h, the malondialdehyde (MDA) and protein carbonyl (PCO) were detected in untreated ECV304 (control) and in HNP-1 transfected ECV304 in the presence and absence of siRNA against HNP-1. Flow cytometry and fluorescence microscopy were used to detect the generation of oxygen free radical in the ECV304 which have been pretreated by LDL, LPS and HNP-1, respectively. RESULT: Compared with control group, MDA level was significantly increased in HNP-1 transfected [(4.21 ± 0.03) vs. (3.15 ± 0.02) nmol/mg · pro] or in HNP-1 stimulated ECV304 cells [(14.49 ± 1.10) vs. (9.47 ± 1.18) nmol/mg · pro], which could be significantly downregulated by siRNA [(3.76 ± 0.48) vs. (4.54 ± 0.28) nmol/mg·pro, all P < 0.05]. PCO was also significantly increased in HNP-1 transfected ECV304 cells. The levels of free radical were significantly increased in HNP-1 transfected or HNP-1 stimulated ECV304 cells. CONCLUSION: HNP-1 can enhance the LDL oxidation ability of human endothelial cells via promoting the generation of free radicals.

Inhibitory effect of paclitaxel on endothelial cell adhesion and migration.

The long-term success of percutaneous coronary interventions has been limited by restenosis. Therefore, local delivery of paclitaxel, an antiproliferative agent, using drug-eluting stents has been applied to prevent in-stent restenosis. However, paclitaxel not only inhibits smooth muscle cell proliferation, but also delays re-endothelialization of the damaged site, which may cause potentially life-threatening cardiovascular adverse events, especially late and very late stent thrombosis. We investigated the role of paclitaxel in endothelial cell line ECV304 adhesion and migration. Accordingly, changes in vasodilator-stimulated phosphoprotein protein (VASP) phosphorylation and cAMP-dependent protein kinase activity during ECV304 cell detachment and reattachment were investigated as well. The results showed that the decrease in VASP phosphorylation paralleled the inhibition of cAMP-dependent protein kinase (PKA) activity in the presence of paclitaxel (10 microg/l). Cell adhesion assay and two- and three-dimensional cell migration assays were performed to determine the effect of paclitaxel on the adhesion and migration of ECV304 cells. Paclitaxel significantly suppresses the adhesion (p < 0.05) and migration of ECV304 cells (p < 0.05). These data suggest that the inhibitory effect of paclitaxel may be produced by decreasing the phosphorylation of VASP via inhibition of PKA activity during ECV304 cell adhesion and migration.

Periplaneta americana extract promotes intestinal mucosa repair of ulcerative colitis in rat.

PURPOSE: To investigate the mechanism of Periplaneta americana extract promoting intestinal mucosal repair of OXZ-induced colitis in rat. METHODS: All experiments used an equal number of male and female SD rats (n=48). We injected OXZ into the colon to induce UC rat model. To determine the optimal concentration of P. Americana's extract (PA-40), it was classified into low (L), medium (M), and high (H) doses. After OXZ treatment, each drug was administered by enema for 7 consecutive days. Rats were divided into the following 6 groups: (1) Saline treatment group (NC), (2) OXZ treatment UC model group (MC), (3) OXZ + budesonide group (BUN), (4) OXZ + PA-40 L group, (5) OXZ + PA-40 M group, (6) OXZ + PA-40 H group. Disease activity index (DAI) scores, colon length, histopathological score, serum cytokine level (IL-4, IL-10, iNOS, tNOS), and amount of MPO, EGF, IL-13 in colonic mucosa were measured. RESULTS: PA treatment had a significant healing effect on the OXZ-colitis model and significantly reduced the lesioned area, especially in the PA-40H groups. PA treatment did not alter the expression of IL-10 and MPO level, but increased EGF (epidermal growth factor) and decrease IL-13 in the colonic tissue. PA inhibited the rise of NOSs (nitric oxide synthase) and decreased the serum IL-4 level. CONCLUSIONS: The data suggest that Periplaneta americana extract may be a potential compound for the treatment of colonic lesions. The mechanism may be related to inhibiting the secretion of IL-13 and promoting the formation of EGF.

Native low density lipoprotein promotes lipid raft formation in macrophages.

Oxidized low­density lipoprotein (LDL) has an important role in atherogenesis; however, the mechanisms underlying cell­mediated LDL oxidation remain to be elucidated. The present study investigated whether native­LDL induced lipid raft formation, in order to gain further insight into LDL oxidation. Confocal microscopic analysis revealed that lipid rafts were aggregated or clustered in the membrane, which were colocalized with myeloperoxidase (MPO) upon native LDL stimulation; however, in the presence of methyl­ß­cyclodextrin (MßCD), LDL­stimulated aggregation, translocation, and colocalization of lipid rafts components was abolished.. In addition, lipid raft disruptors MßCD and filipin decreased malondialdehyde expression levels. Density gradient centrifugation coupled to label­free quantitative proteomic analysis identified 1,449 individual proteins, of which 203 were significantly upregulated following native­LDL stimulation. Functional classification of the proteins identified in the lipid rafts revealed that the expression levels of translocation proteins were upregulated. In conclusion, the results of the present study indicated that native­LDL induced lipid raft clustering in macrophages, and the expression levels of several proteins were altered in the stimulated macrophages, which provided novel insights into the mechanism underlying LDL oxidation.

Periplaneta americana extract promotes intestinal mucosa repair of ulcerative colitis in rat

Abstract Purpose: To investigate the mechanism of Periplaneta americana extract promoting intestinal mucosal repair of OXZ-induced colitis in rat. Methods: All experiments used an equal number of male and female SD rats (n=48). We injected OXZ into the colon to induce UC rat model. To determine the optimal concentration of P. Americana's extract (PA-40), it was classified into low (L), medium (M), and high (H) doses. After OXZ treatment, each drug was administered by enema for 7 consecutive days. Rats were divided into the following 6 groups: (1) Saline treatment group (NC), (2) OXZ treatment UC model group (MC), (3) OXZ + budesonide group (BUN), (4) OXZ + PA-40 L group, (5) OXZ + PA-40 M group, (6) OXZ + PA-40 H group. Disease activity index (DAI) scores, colon length, histopathological score, serum cytokine level (IL-4, IL-10, iNOS, tNOS), and amount of MPO, EGF, IL-13 in colonic mucosa were measured. Results: PA treatment had a significant healing effect on the OXZ-colitis model and significantly reduced the lesioned area, especially in the PA-40H groups. PA treatment did not alter the expression of IL-10 and MPO level, but increased EGF (epidermal growth factor) and decrease IL-13 in the colonic tissue. PA inhibited the rise of NOSs (nitric oxide synthase) and decreased the serum IL-4 level. Conclusions: The data suggest that Periplaneta americana extract may be a potential compound for the treatment of colonic lesions. The mechanism may be related to inhibiting the secretion of IL-13 and promoting the formation of EGF.