Overexpression of the steroidogenic acute regulatory protein increases the expression of ATP-binding cassette transporters in microvascular endothelial cells (bEnd.3).

OBJECTIVE: To determine the effect of steroidogenic acute regulatory protein (StAR) overexpression on the levels of adenosine triphosphate (ATP)-binding cassette transporter A1 (ABCA1) and ATP-binding cassette transporter G1 (ABCG1) in an endothelial cell line (bEnd.3). METHODS: The StAR gene was induced in bEnd.3 cells with adenovirus infection. The infection efficiency was detected by fluorescence activated cell sorter (FACS) and fluorescence microscopy. The expressions of StAR gene and protein levels were detected by real-time polymerase chain reaction (PCR) and Western blot. The gene and protein levels of ABCA1 and ABCG1 were detected by real-time PCR and Western blot after StAR overexpression. RESULTS: The result shows that StAR was successfully overexpressed in bEnd.3 cells by adenovirus infection. The mRNA and protein expressions of ABCA1 and ABCG1 were greatly increased by StAR overexpression in bEnd.3 cells. CONCLUSION: Overexpression of StAR increases ABCA1 and ABCG1 expressions in endothelial cells.

Effects of ginkgo biloba extract EGb761 on expression of RAGE and LRP-1 in cerebral microvascular endothelial cells under chronic hypoxia and hypoglycemia.

Alzheimer's disease (AD), characterized by accumulation of amyloid-beta protein (Abeta) in brain parenchyma, is closely associated with brain ischemia. Decreased clearance of Abeta from brain is the main cause of Abeta accumulation in sporadic AD. However, the mechanisms underlying ischemia-mediated AD pathogenesis remain unclear. The receptor for advanced end glycation products (RAGE) and low-density lipoprotein receptor-related protein-1 (LRP-1) expressed at blood brain barrier (BBB) are actively involved in Abeta clearance. RAGE is thought to be a primary transporter of Abeta across BBB into the brain from the systemic circulation, while LRP-1 mediates the transport of Abeta out of the brain. Ginkgo biloba extract EGb761, a traditional Chinese medicine, has been widely used in the treatment of AD. To investigate the effects of EGb761 on the expression of RAGE and LRP-1 in endothelial cells in response to ischemic injury, we cultured bEnd.3 cells, an immortalized mouse cerebral microvessel endothelial cell line, under a chronic hypoxic and hypoglycemic condition (CHH) to mimic ischemic injury of BBB, and then treated with EGb 761. We found that EGb 761 markedly ameliorated the damage (evaluated by MTT assay) from CHH. Moreover, we demonstrated that CHH led to a significant increase in the expression of RAGE both at the mRNA and protein levels at all times (24, 36, and 48 h), conversely; CHH induced a dramatic decrease in LRP-1 mRNA and protein expression at both 36 and 48 h. The results indicated that CHH has differential effects on the expression of RAGE and LRP-1. Furthermore, EGb761 significantly reversed CHH-induced upregulation of RAGE expression and downregulation of LRP-1 expression. Our findings suggest that EGb761 favor clearance of Abeta via regulating the expression of RAGE and LRP-1 during brain ischemia. This may provide a new insight into a possible molecular mechanism underlying brain ischemia-mediated AD pathogenesis, and potential therapeutic application of EGb 761 in treatment of AD.

Effects of RNA interference-induced tryptase down-regulation in P815 cells on IL-6 and TNF-alpha release of endothelial cells.

OBJECTIVE: To explore the effects of down-regulated tryptase expression in mast cells on the synthesis and release of interleukin-6 (IL-6) and tumor necrosis factor-alpha (TNF-alpha) of vascular endothelial cells. METHODS: Tryptase-siRNA (small-interfering RNA) vector was constructed to inhibit tryptase expression in P815 cells. The medium of P815 cells treated by the tryptase-siRNA (RNAi-P815 group) or pure vector (P815 group) was collected and used to culture bEnd.3 cells. The messenger RNAs (mRNAs) of IL-6 and TNF-alpha in bEnd.3 cells and their protein levels in the medium were measured by reverse transcription polymerase chain reaction (RT-PCR) and enzyme-linked immunosorbent assay (ELISA), respectively. RESULTS: IL-6 and TNF-alpha mRNAs in bEnd.3 cells cultured in RNAi-P815-conditioned medium decreased significantly compared to those in P815-conditioned medium. Consistently, IL-6 and TNF-alpha protein levels in the medium of bEnd.3 of RNAi-P815 group were lower than those of P815 group. CONCLUSION: Reduced tryptase expression significantly inhibited the synthesis and release of IL-6 and TNF-alpha in vascular endothelial cells. RNA interference targeting tryptase expression may be a new anti-inflammatory strategy for vascular diseases.

[Effects of RNAi on cyclooxygenase-2 expression and biologic activity of human rheumatoid arthritis synovial fibroblasts].

OBJECTIVE: To screen highly efficient small interfering RNA (siRNA) targeting human cyclooxygenase-2 (hCOX-2) mRNA on human rheumatoid arthritis synovial fibroblasts (RASF) and to further study the impact there on prostaglandin E2 (PGE2) and cytokines, such as interleukin-1beta (IL-1beta), interleukin-6 (IL-6), timorous necrosis factor-alpha (TNF-alpha), and vascular endothelial growth factor (VEGF). METHODS: 4 lines of COX-2 mRNA siRNA (1(#) - 4(#) siRNA) were designed and transfected into the fibroblasts from the synovial membrane of a patient with rheumatoid arthritis (RASF). Phorbol ester was added 4 hours later. A scrambled line (NC) group and a blank control (CTL) group were used. RT-PCR and Western blot ting were used to detect the mRNA and protein expression of COX-2 36 and 48 hours after transfection. The levels of PGE2, IL-1beta, IL-6, TNF-alpha, and VEGF were measured by ELISA. RESULTS: RT-PCR showed that the absorbance ratios of the positively interfering groups, NC, and 1(#) - 3(#) siRNA groups, to CTL group were 0.72, 0.3, 0.25, 0.4, and 0.04 respectively. The ratios of the positively interfering groups to CTL group were 1.04, 0.52, 0.39, 0.9, and 36 h after transfection and 1.05, 0.52, 0.51, 0.9, and 0.15 respectively 48 h after transfection. The levels of PGE2, IL-1beta, IL-6, TNF-alpha, and VEGF in the culture supernatant were lower in the 4(#) siRNA group than in other groups 24, 36, and 48 h after transfection. The death rates of RASF of all trial groups were within the range of 9% - 11% and there were not statistically significant differences between the CTL group and the siRNA groups or between the 4(#) siRNA and other siRNA groups. CONCLUSION: 4(#) siRNA effectively inhibits the expression of COX-2 mRNA and protein the level of PGE2, IL-1beta, IL-6, TNF-alpha, and VEGF in the clear supernatant of the 4(#) group is lowest.

Up regulation of interleukin-8 expressions induced by mast cell tryptase via protease activated receptor-2 in endothelial cell line.

BACKGROUND: Protease activated receptor-2 is cleaved and activated by trypsin or mast cell tryptase and may play an important role in inflammation. However, it is unknown whether PAR-2 can mediate tryptase-induced inflammatory reaction. This study was conduct to investigate whether PAR-2 could be the activated by mast cell tryptase and medicated the tryptase induced interleukin-8 expression in endothelial cells. METHODS: Protease activated receptor-2 expression was found in endothelial cell lines ECV304 cell by reverse transcription-polymerase chain reaction (RT-PCR) and Western blotting. Interleukin-8 stimulated by purified human mast cell tryptase was determined by RT-PCR and enzyme linked immunosorbent assay (ELISA). Data were analysed by the S-N-K one-way ANOVA test. RESULTS: The present study shows that mRNA and protein of protease activated receptor-2 could be expressed in ECV304 cells, and tryptase upregulated the expression levels of both interleukin-8 mRNA and protein. The increased expression of interleukin-8 was inhibited by an antiprotease activated receptor-2 monoclonal antibody, SAM11. An additional band was observed by Western blotting after the incubation of ECV304 cells with tryptase for 2 hours, which suggested that protease activated receptor-2 was activated. CONCLUSION: Protease activated receptor-2 can mediate the mast cell tryptase stimulated expression of interleukin-8 in ECV304 cell.