Objectives. Dendritic cells (DCs) can inhibit immune response by clonal anergy when immature. Recent studies have shown that immature DCs (iDCs) may serve as a live cell vaccine after specific ...antigen pulse based on its potential of blocking antibody production. In this study, we aimed to investigate the effects of nuclear antigen-pulsed iDCs in the treatment of lupus-like renal damages induced by anti-dsDNA antibodies.
Methods. iDCs were generated from haemopoietic stem cells in bone marrow and then pulsed in vitro with nuclear antigen. The iDC vaccine and corresponding controls were injected into mice with lupus-like renal damages. The evaluation of disease was monitored by biochemical parameters and histological scores. Anti-dsDNA antibody isotypes and T-lymphocyte-produced cytokines were analysed for elucidating therapeutic mechanisms.
Results. The mice treated with antigen-pulsed iDCs had a sustained remission of renal damage compared with those injected with non-pulsed iDCs or other controls, including decreased anti-dsDNA antibody level, less proteinuria, lower blood urea nitrogen and serum creatinine values, and improved histological evaluation. Analysis on isotypes of anti-dsDNA antibody showed that iDC vaccine preferentially inhibited the production of IgG3, IgG2b and IgG2a. Furthermore, administration of antigen-treated iDCs to mice resulted in significantly reduced IL-2, IL-4 and IL-12 and IFN-γ produced by T-memory cells. Conversely, the vaccination of antigen-pulsed mature DCs led to increased anti-dsDNA antibody production and an aggravation of lupus-like disease in the model.
Conclusions. These results suggested the high potency of iDC vaccine in preventing lupus-like renal injuries induced by pathogenic autoantibodies.
The beta-amyloid (A beta 1-40) peptide has previously been shown to enhance phenylephrine contraction of aortic rings in vitro. We have employed a novel observation, that A beta peptides enhance ...endothelin-1 (ET-1) contraction, to examine the relationship between vasoactivity and potential amyloidogenicity of A beta peptides, the role played by free radicals and calcium in the vasoactive mechanism, and the requirement of an intact endothelial layer for enhancement of vasoactivity. Rings of rat aortae were constricted with ET-1 before and after addition of amyloid peptide and/or other compounds, and a comparison was made between post- and pre-treatment contractions. In this system, vessel constriction is consistently dramatically enhanced by A beta 1-40, is enhanced less so by A beta 1-42, and is not enhanced by A beta 25-35. The endothelium is not required for A beta vasoactivity, and calcium channel blockers have a greater effect than antioxidants in blocking enhancement of vasoconstriction by A beta peptides. In contrast to A beta-induced cytotoxicity, A beta-induced vasoactivity is immediate, occurs in response to low doses of freshly solubilized peptide, and appears to be inversely related to the amyloidogenic potential of the A beta peptides. We conclude that the mechanism of A beta vasoactivity is distinct from that of A beta cytotoxicity. Although free radicals appear to modulate the vasoactive effects, the lack of requirement for endothelium suggests that loss of the free radical balance (between NO and O2-) may be a secondary influence on A beta enhancement of vasoconstriction. These effects of A beta on isolated vessels, and reported effects of A beta in cells of the vasculature, suggest that A beta-induced disruption of vascular tone may be a factor in the pathogenesis of cerebral amyloid angiopathy and Alzheimer's disease. Although the mechanism of enhanced vasoconstriction is unknown, it is reasonable to propose that in vivo contact of A beta peptides with small cerebral vessels may increase their tendency to constrict and oppose their tendency to relax. The subclinical ischemia resulting from this would be expected to up-regulate beta APP production in and around the vasculature with further increase in A beta formation and deposition. The disruptive and degenerative effects of such a cycle would lead to the complete destruction of cerebral vessels and consequently neuronal degeneration in the affected areas.
Accumulating evidence suggests that β-amyloid (Aβ)-induced inflammatory reactions may partially drive the pathogenesis of Alzheimer's disease (AD). Recent data also implicate similar inflammatory ...processes in cerebral amyloid angiopathy (CAA). To evaluate the roles of Aβ in the inflammatory processes in vascular tissues, we have tested the ability of Aβ to trigger inflammatory responses in cultured human vascular cells. We found that stimulation with Aβ dose-dependently increased the expression of CD40, and secretion of interferon-γ (IFN-γ) and interleukin-1β (IL-1β) in endothelial cells. Aβ also induced expression of IFN-γ receptor (IFN-γR) both in endothelial and smooth muscle cells. Characterization of the Aβ-induced inflammatory responses in the vascular cells showed that the ligation of CD40 further increased cytokine production and/or the expression of IFN-γR. Moreover, IL-1β and IFN-γ synergistically increased the Aβ-induced expression of CD40 and IFN-γR. We have recently found that Aβ induces expression of adhesion molecules, and that cytokine production and interaction of CD40–CD40 ligand (CD40L) further increase the Aβ-induced expression of adhesion molecules in these same cells. These results suggest that Aβ can function as an inflammatory stimulator to activate vascular cells and induces an auto-amplified inflammatory molecular cascade, through interactions among adhesion molecules, CD40–CD40L and cytokines. Additionally, Aβ
1–42, the more pathologic form of Aβ, induces much stronger effects in endothelial cells than in smooth muscle cells, while the reverse is true for Aβ
1–40. Collectively, these findings support the hypothesis that the Aβ-induced inflammatory responses in vascular cells may play a significant role in the pathogenesis of CAA and AD.
In this article,the shrinking of Dongting Lake and its progressively weakening connection with the Yangtze River and their impact on flooding before and after the implementation of the Three Gorges ...Project are analyzed.In recent decades,human activity combined with natural processes has altered the flow of the middle reach channel of the Yangtze River and interfered with its connection with Dongting Lake.This has resulted in progressively more frequent flooding in the area.This study uses hydrological data to analyze the annual maximum discharge and annual maximum stage development of the middle reach of the Yangtze River and Dongting Lake.In recent decades before the Three Gorges Project became operational in 2003,the annual maximum discharge and the maximum stage recorded in the middle reach of the river downstream of Dongting Lake had increased,a result of the weakening of the flood regulation function of Dongting Lake;the annual maximum stage at Luoshan station（downstream,close to the confluence of the Yangtze River and Dongting Lake） had risen by about 2.0 m during 1955-2005,（1.5 m attributed to annual maximum discharge and 0.5 m to river channel deposition）.Observational data recorded after the Three Gorges Project was put into operation in 2003,it can be seen that deposition in the Dongting Lake has nearly ceased and the lake＇s connection with the Yangtze River is stable.It is evident that the flood regulation function of Dongting Lake will continue,and that during the lifetime of the Three Gorges Project,the flood situation in the middle reach of the Yangtze River and Dongting Lake will remain stable.
Anti-double-stranded DNA (dsDNA) IgG causes renal damage in patients with lupus nephritis by cross-reacting with multiple autoantigens, including alpha-actinin-4, in mesangial cells (MCs). However, ...how the cross-reactions play a role in mesangial phenotypic abnormalities is not well understood. Here, we investigated the effects of the fragment antigen-binding (Fab) of anti-dsDNA IgG3 on the biochemical properties of alpha-actinin-4. Experiments revealed that anti-dsDNA Fab specifically binds to alpha-actinin-4, but not G-actin. The binding by anti-dsDNA Fab sequentially increases the positive charge of alpha-actinin-4 and inhibits the affinity of alpha-actinin-4 to calcium ions. By the low shear viscosity and a co-sedimentation assay, we found that the alpha-actinin-4-induced F-actin gelation improves when anti-dsDNA Fab is added. However, the Fab control has no such effect on F-actin gelation. Furthermore, the in vitro cultured MCs exhibit higher F-actin expression and transforming growth factor-β1 synthesis after the incubation with anti-dsDNA Fab. Therefore, our results indicated that anti-dsDNA Fab may enhance F-actin formation by the proprietary modification of alpha-actinin-4, which could partially explain the myofibroblast-like phenotype of MCs in anti-dsDNA-positive lupus nephritis.
Anti–double-stranded DNA (dsDNA) antibodies have been indicated to play a major role in the pathogenesis of lupus nephritis (LN), which is characterized by mesangial alterations, including phenotypic ...changes. To explore the effects of anti-dsDNA antibodies on the phenotype of mesangial cells (MCs), the anti-dsDNA IgG in sera and histological features of glomeruli were analyzed in the mice models of immune-complex glomerulonephritis. The MCs were cultured
in vitro
with the addition of anti-dsDNA or non-anti-dsDNA IgG. Compared to the anti-dsDNA-negative controls, the serum positive mice had increased extracellular matrix accumulation and higher alpha-smooth muscle actin expression in the mesangial region. The anti-dsDNA IgG enhanced the synthesis of transforming growth factor beta, alpha-smooth muscle actin, and fibronectin, and even induced the myofibroblast-like morphological features in cultured MCs. Our results indicated that anti-dsDNA antibodies contribute to the phenotypic changes in MCs, which suggests another mechanism of renal injuries in LN induced by anti-dsDNA antibodies.
Increasing evidence implicates oxidative stress as partially responsible for the neurodegenerative process of Alzheimer's disease (AD). Recent reports show an increased production of nitrotyrosine in ...AD brains, suggesting that peroxynitrite is produced in excess in this disease. Furthermore, incidence of cerebral amyloid angiopathy in AD cases is very frequent (83%), strongly suggesting a vascular component of AD pathogenesis. We have evaluated the hypothesis that peroxynitrite could be responsible for mediating the cytotoxicity and vasoactivity induced by the amyloid-beta1-40 (Abeta) peptide. Rat brain endothelial cells (RBE-4) appear to be sensitive to Abeta-induced toxicity but not to the cytotoxicity induced by peroxynitrite. Addition of Cu/Zn superoxide dismutase to cell culture media, which is only able to clear extracellular superoxide, was not effective in blocking Abeta-induced toxicity. However, we were able to partially block Abeta-induced cytotoxicity by using Mn(III)tetrakis(4-benzoic acid) porphyrin (MnTBAP) which dismutes superoxide intracellularily. Yet, MnTBAP was not able to prevent the vasoactivity triggered by Abeta. Moreover, addition of peroxynitrite to rat aortae did not modulate the vasotension induced by Abeta. We conclude that intracellular superoxide radicals may contribute to Abeta-induced cytotoxicity. Our results also indicate that peroxynitrite does not significantly contribute to Abeta-induced cytotoxicity in rat brain endothelial cells (RBE-4) or vasoactivity in rat aortae. These results suggest that therapeutic efforts aimed at removal of reactive oxygen species with SOD is unlikely to be beneficial for treatment of Abeta-induced endothelial dysfunction. However, compounds that clear free radicals intracellularly may well be beneficial.
Bacillus subtilis is popularly used as a probiotic in many fields. Although recent research has found that some secondary metabolites of B. subtilis could cause hemolysis, the hemolytic mechanism in ...B. subtilis is still unclear. In this paper, the hemolysis-associated gene ytjA was cloned and expressed in Escherichia coli, and the hemolytic activity of the expressed soluble protein was indicated by the presence of clear hemolytic zones on sheep blood agar plates. In addition, reverse transcriptase-polymerase chain reaction analysis confirmed that the ytjA gene was transcribed in B. subtilis. These results suggest that ytjA is one of the hemolysin genes responsible for hemolysis in B. subtilis.
Marine Spatial Planning (MSP) has emerged as an integrated policy tool, which seeks to identify and manage different uses of the sea in a conducted manner to increase what has become known as blue ...growth opportunities and address marine environmental issues caused by land-sea interactions. In the historical geography of China's marine temporal and spatial development, the past MSP, whether it was a real or institutionalized system, is the basis for the interaction and temporal understanding of Chinese human-sea relationship, from which experience and lessons would be learned. The development of MSP in China origins following the implementation of the opening-up policy of 1979. These key phases of the development of the MSP system can be identified and there have been significant changes in the geographical extent and aim of MSP. In this paper, we not only explain the emergence of integrated terrestrial planning (containing land and sea) in the context of what has been happening within China but also clarify some of the challenges facing the new integrated and broad terrestrial approach, which considers the land and sea as being a single territory.
Bacillus subtilis is commonly used as a probiotic. Recently, some metabolites of B. subtilis were reported to cause hemolysis; however, the mechanism by which these metabolites cause hemolysis ...remains to be clarified. In this study, we cloned the hemolysis-associated gene yhdT and constructed a yhdT gene-deletion mutant of the B. subtilis 224 strain. Further, we determined the hemolytic activity of the culture supernatant of the yhdT gene-deletion mutant and found that the hemolytic activity of the yhdT gene-deletion mutant was lower than that of wild-type B. subtilis 224. Thus, our results indicate that the yhdT gene contributes to the hemolytic activity of B. subtilis 224.
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