eEF-2 Phosphorylation Down-Regulates P-Glycoprotein Over-Expression in Rat Brain Microvessel Endothelial Cells

ObjectiveWe investigated whether glutamate, NMDA receptors, and eukaryote elongation factor-2 kinase (eEF-2K)/eEF-2 regulate P-glycoprotein expression, and the effects of the eEF-2K inhibitor NH125 on the expression of P-glycoprotein in rat brain microvessel endothelial cells (RBMECs).MethodsCortex was obtained from newborn Wistar rat brains. After surface vessels and meninges were removed, the pellet containing microvessels was resuspended and incubated at 37°C in culture medium. Cell viability was assessed by the MTT assay. RBMECs were identified by immunohistochemistry with anti-vWF. P-glycoprotein, phospho-eEF-2, and eEF-2 expression were determined by western blot analysis. Mdr1a gene expression was analyzed by RT-PCR.ResultsMdr1a mRNA, P-glycoprotein and phospho-eEF-2 expression increased in L-glutamate stimulated RBMECs. P-glycoprotein and phospho-eEF-2 expression were down-regulated after NH125 treatment in L-glutamate stimulated RBMECs.ConclusionseEF-2K/eEF-2 should have played an important role in the regulation of P-glycoprotein expression in RBMECs. eEF-2K inhibitor NH125 could serve as an efficacious anti-multidrug resistant agent.     

QUANTITATIVE VARIATION OF ECDYSTEROIDS OF IXODID TICKS

Abstract  In order to explore the role of ecdysteroids in development and reproduction of ixodid ticks, we studied the quantitative variation of ecdysteroids in the hemolymph, synganglion, ovary and whole body of the female ixodid ticks, Dermacentor niveus and Haemaphysalis longicornis , before and after engorgement and oviposition by HPLC and RIA. The ecdysteroid content in eggs of these ticks was determined by HPLC. The results indicated that before engorgement the quantitative variation of ecdysteroids in the whole female body was not significant, but their levels increased rapidly after engorgement. The ecdysteroid titer in hemolymph was peaked on the 5th day after engorgement, which was one day prior to oviposition. It may be regarded as a singnal of oviposition. In the synganglion the peak of ecdysteroid level occurred also on the 5th day after engorgement. This is coincident with the secretory activity of neurosecretory cells of synganglion. From the 3rd day after engorgement until oviposition the ecdysteroid level in the ovary increased rapidly. Ecdysteroids were detected in eggs of H. longicornis too. They stem from ovary and accumulated with the process of embryonic development.     

Comparative Analysis of Endogenous Hormones and Metabolite Profiles in Early-Spring Flowering Plants and Unflowered Plants Revealing the Strategy of Blossom

Journal of Plant Growth Regulation - Early-spring plants are a special type of plant that complete their life cycle promptly in cold, early spring. Very little effort has been made into researching...     

Maturation of Human Herpesvirus 6A Glycoprotein O Requires Coexpression of Glycoprotein H and Glycoprotein L

Glycoprotein O (gO) is conserved among betaherpesviruses, but little is known about the maturation process of gO in human herpesvirus 6 (HHV-6). We found that HHV-6 gO maturation was accompanied by cleavage of its carboxyl terminus and required coexpression of gH and gL, which promoted the export of gO out of the endoplasmic reticulum (ER). Finally, we also found that gO was not required for HHV-6A growth in T cells.     

Uncovering the mystery of Ebola virus entry: Lock and key

正How Ebola virus(EBOV)enters a host cell remains intriguingly mysterious to the public.Recently,a study led by George F Gao and his colleagues has unveiled how the primed glycoprotein on the envelope of EBOV binds to its endosomal receptor Niemann-Pick C1(NPC1)molecule during the process of virus membrane fusion with the host cells,an essential step for viral entry(Wang et al.,2016).This fine resolution of the viral glycoprotein with NPC1 at the atomic level sheds light on the development of therapeutic inhibitors against EBOV infection.