Cyclosporin A impairs dendritic cell migration by regulating chemokine receptor expression and inhibiting cyclooxygenase-2 expression

Migration of dendritic cells (DCs) into tissues and secondary lymphoid organs plays a crucial role in the initiation of innate and adaptive immunity. In this article, we show that cyclosporin A (CsA) impairs the migration of DCs both in vitro and in vivo. Exposure of DCs to clinical concentrations of CsA neither induces apoptosis nor alters development but does impair cytokine secretion, chemokine receptor expression, and migration. In vitro, CsA impairs the migration of mouse bone marrow-derived DCs toward macrophage inflammatory protein-3beta (MIP-3beta) and induces them to retain responsiveness to MIP-1alpha after lipopolysaccharide (LPS)-stimulated DC maturation, while in vivo administration of CsA inhibits the migration of DCs out of skin and into the secondary lymphoid organs. CsA impairs chemokine receptor and cyclooxygenase-2 (COX-2) expression normally triggered in LPS-stimulated DCs; administration of exogenous prostaglandin E2 (PGE2) reverses the effects of CsA on chemokine receptor expression and DC migration. Inhibition of nuclear factor-kappaB (NF-κB) and mitogen-activated protein kinase (MAPK) pathway signaling by CsA may be responsible for the CsA-mediated effects on the regulation of chemokine receptor and cyclooxygenase-2 (COX-2) expression. Impairment of DC migration due to inhibition of PGE2 production and regulation of chemokine receptor expression may contribute, in part, to CsA-mediated immunosuppression.

CREG regulates vascular endothelial cell migration mediated by ILK-β-parvin signal pathway

Background To investigate the effects and mechanisms of cellular repressor of ElA stimulated genes (CREG) on endothelial cell(EC) migration.Methods vascular endothelial cells(VE),CREG overexpression VEs, CREG suppression VEs and VEs transfected with CREG gene modified adenovirus(Ad-CREG) were cultured with dulbecco’s modified eagle’s medium contained 10%fetal calf serum. Western blot was used to detect the protein level of CREG and integrin-linked kinase(ILK) in the four kind ECs.Tran-swell migration model was applied to compare the migration cell number of the four kind ECs.Two kinds of ILK mutant plasmids;PCXN2-flag-ILK wt-IRES-GFP(wild-type ILK)and PCXN2-flag-ILK p-parvin-IRES-GFP(P-parvin-binding mutant) were used to transfect VS and VE respectively,then the two kind transfection ECs were named as VS-wtILK and VE-P -parvin which were selected by G418(600ng/ml)for 2 weeks;Transwell migration model was applied to compare migration capability before and after ILK plasmids transfecting VE and VS.Results Western blot analysis showed that CREG overexpression promoted ILK expression in ECs,on the contrary,ILK expression was down-regulated in CREG silent ECs(P【0.05).Further more,ILK expression was up-regulated obviously in VE transfected with Ad-CREG(P【 0.05);Transwell migration model showed that EC’s migration capability was positively correlated with the expression level of CREG in EC,that is,CREG overexpression induced VE migration and CREG silent suppressed VE migration, moreover,Ad-CREG transfecting VE showed better migration capability accompanied with CREG expression increase by transwell migration model(P【0.05).In order to know the relationship between ILK expression and cell migration,we obtained stable transfection cell strains of VS-wtILK and VE-Pparvin, transwell migration model demonstrated that VS-wtILK remarkably corrected the poor migration capability of VS(P【 0.01),butβ-parvin combining site mutation in ILK genes inhibited VE migration markedly(P【0.01).Conclusions ILKp -parvin signal pathway mediated vascular endothelial cell migration induced by CREG.

Endogenous bioelectric fields: a putative regulator of wound repair and regeneration in the central nervous system

Studies on a variety of highly regenerative tissues, including the central nervous system（CNS） in non-mammalian vertebrates, have consistently demonstrated that tissue damage induces the formation of an ionic current at the site of injury. These injury currents generate electric fields（EF） that are 100-fold increased in intensity over that measured for uninjured tissue. In vitro and in vivo experiments have convincingly demonstrated that these electric fields（by their orientation, intensity and duration） can drive the migration, proliferation and differentiation of a host of cell types. These cellular behaviors are all necessary to facilitate regeneration as blocking these EFs at the site of injury inhibits tissue repair while enhancing their intensity promotes repair. Consequently, injury-induced currents, and the EFs they produce, represent a potent and crucial signal to drive tissue regeneration and repair. In this review, we will discuss how injury currents are generated, how cells detect these currents and what cellular responses they can induce. Additionally, we will describe the growing evidence suggesting that EFs play a key role in regulating the cellular response to injury and may be a therapeutic target for inducing regeneration in the mammalian CNS.

THE PIGMENT-PROTEIN COMPLEXES OF HIGHER PLANTS MIGRATION IN THYLAKOID AND THE REGULATION OF LIGHT ENERGY DISTRIBUTION BETWEEN PHOTOSYSTEMS

Appressed and non-appressed lamella membranes of Castor bean leaf chloroplasts were separated by non-ionic detergent Triton-X 100.Appressed membranes showed a high oxygen-evolving activity and low chl a/b ratio. Examining with SDS-PTGE and liquid nitrogen temperature fluorescence measurement showed that they contained only PSII and light-harvesting pigment-protein complexes (LHCP),and there was no detectable amount of PSI. Freeze-fracture electromicroscopic observation confirmed that this part was really an appressed lamella membrane. Through divalent cation Mg^(++), the thylakoid membranes were induced to unstack and restack.With the addition of Mg^(++), the fluorescence intensity was changed instantly. We realized that there existed two processes:One was a rapid process which was accomplished within 30 s. The other was a slow process of which the time duration was about 60 min. This dual effects of Mg^(++) had not been reported before.We had analyzed the change of F685/F730 and discussed the possible rneehanis ms of light energy distribution between photosystems.