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71.
Colgrave ML Xi L Lehnert SA Flatscher-Bader T Wadensten H Nilsson A Andren PE Wijffels G 《Proteomics》2011,11(7):1264-1276
The hypothalamus is the central regulatory region of the brain that links the nervous system to the endocrine system via the pituitary gland. It synthesizes and secretes neuropeptide hormones, which in turn act to stimulate or inhibit the secretion of pituitary hormones. We have undertaken a detailed MS investigation of the peptides present in the bovine hypothalamus by adapting a novel heat stabilization methodology, which improved peptide discovery to direct our studies into the molecular mechanisms involved in bovine reproduction. The untreated samples contained large numbers of protein degradation products that interfered with the analysis of the neuropeptides. In the thermally stabilized samples, we were able to identify many more neuropeptides that are known to be expressed in the bovine hypothalamus. Furthermore, we have characterized a range of post-translational modifications that indicate the presence of processed intact mature neuropeptides in the stabilized tissue samples, whereas we detected many trimmed or truncated peptides resulting from post-mortem degradation in the untreated tissue samples. Altogether, using an optimized workflow, we were able to identify 140 candidate neuropeptides. We also nominate six new candidate neuropeptides derived from proSAAS, secretogranin-2 and proTRH. 相似文献
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75.
Human mineralocorticoid receptor expression renders cells responsive for nongenotropic aldosterone actions 总被引:7,自引:0,他引:7
Grossmann C Benesic A Krug AW Freudinger R Mildenberger S Gassner B Gekle M 《Molecular endocrinology (Baltimore, Md.)》2005,19(7):1697-1710
The steroid hormone aldosterone is important for salt and water homeostasis as well as for pathological tissue modifications in the cardiovascular system and the kidney. The mechanisms of action include a classical genomic pathway, but physiological relevant nongenotropic effects have also been described. Unlike for estrogens or progesterone, the mechanisms for these nongenotropic effects are not well understood, although pharmacological studies suggest a role for the mineralocorticoid receptor (MR). Here we investigated whether the MR contributes to nongenotropic effects. After transfection with human MR, aldosterone induced a rapid and dose-dependent phosphorylation of ERK1/2 and c-Jun NH2-terminal kinase (JNK) 1/2 kinases in Chinese hamster ovary or human embryonic kidney cells, which was reduced by the MR-antagonist spironolactone and involved cSrc kinase as well as the epidermal growth factor receptor. In primary human aortic endothelial cells, similar results were obtained for ERK1/2 and JNK1/2. Inhibition of MAPK kinase (MEK) kinase but not of protein kinase C prevented the rapid action of aldosterone and also reduced aldosterone-induced transactivation, most probably due to impaired nuclear-cytoplasmic shuttling of MR. Cytosolic Ca2+ was increased by aldosterone in mock- and in human MR-transfected cells to the same extend due to Ca2+ influx, whereas dexamethasone had virtually no effect. Spironolactone did not prevent the Ca2+ response. We conclude that some nongenotropic effects of aldosterone are MR dependent and others are MR independent (e.g. Ca2+), indicating a higher degree of complexity of rapid aldosterone signaling. According to this model, we have to distinguish three aldosterone signaling pathways: 1) genomic via MR, 2) nongenotropic via MR, and 3) nongenotropic MR independent. 相似文献
76.
De Klerck B Geboes L Hatse S Kelchtermans H Meyvis Y Vermeire K Bridger G Billiau A Schols D Matthys P 《Arthritis research & therapy》2005,7(6):R1208-R1220
CXCL12 (stromal cell-derived factor 1) is a unique biological ligand for the chemokine receptor CXCR4. We previously reported
that treatment with a specific CXCR4 antagonist, AMD3100, exerts a beneficial effect on the development of collagen-induced
arthritis (CIA) in the highly susceptible IFN-γ receptor-deficient (IFN-γR KO) mouse. We concluded that CXCL12 plays a central
role in the pathogenesis of CIA in IFN-γR KO mice by promoting delayed type hypersensitivity against the auto-antigen and
by interfering with chemotaxis of CXCR4+ cells to the inflamed joints. Here, we investigated whether AMD3100 can likewise inhibit CIA in wild-type mice and analysed
the underlying mechanism. Parenteral treatment with the drug at the time of onset of arthritis reduced disease incidence and
modestly inhibited severity in affected mice. This beneficial effect was associated with reduced serum concentrations of IL-6.
AMD3100 did not affect anti-collagen type II antibodies and, in contrast with its action in IFN-γR KO mice, did not inhibit
the delayed type hypersensitivity response against collagen type II, suggesting that the beneficial effect cannot be explained
by inhibition of humoral or cellular autoimmune responses. AMD3100 inhibited the in vitro chemotactic effect of CXCL12 on splenocytes, as well as in vivo leukocyte infiltration in CXCL12-containing subcutaneous air pouches. We also demonstrate that, in addition to its effect
on cell infiltration, CXCL12 potentiates receptor activator of NF-κB ligand-induced osteoclast differentiation from splenocytes
and increases the calcium phosphate-resorbing capacity of these osteoclasts, both processes being potently counteracted by
AMD3100. Our observations indicate that CXCL12 acts as a pro-inflammatory factor in the pathogenesis of autoimmune arthritis
by attracting inflammatory cells to joints and by stimulating the differentiation and activation of osteoclasts. 相似文献
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78.
De Keersmaecker SC Varszegi C van Boxel N Habel LW Metzger K Daniels R Marchal K De Vos D Vanderleyden J 《The Journal of biological chemistry》2005,280(20):19563-19568
We describe an original, short, and convenient chemical synthesis of enantiopure (S)-4,5-dihydroxy-2,3-pentanedione (DPD), starting from commercial methyl (S)-(-)-2,2-dimethyl-1,3-dioxolane-4-carboxylate. DPD is the precursor of autoinducer (AI)-2, the proposed signal for bacterial interspecies communication. AI-2 is synthesized by many bacterial species in three enzymatic steps. The last step, a LuxS-catalyzed reaction, leads to the formation of DPD, which spontaneously cyclizes into AI-2. AI-2-like activity of the synthesized molecule was ascertained by the Vibrio harveyi bioassay. To further validate the biological activity of synthetic DPD and to explore its potential in studying DPD (AI-2)-mediated signaling, a Salmonella typhimurium luxS mutant was constructed. Expression of the AI-2 regulated lsr operon can be rescued in this luxS mutant by addition of synthetic DPD or genetic complementation. Biofilm formation by S. typhimurium has been reported to be defective in a luxS mutant, and this was confirmed in this study to test DPD for chemical complementation. However, biofilm formation of the luxS mutant cannot be restored by addition of DPD. In contrast, introduction of luxS under control of its own promoter complemented biofilm formation. Further results demonstrated that biofilm formation of the luxS mutant cannot be restored with luxS under control of the strong nptII promoter. This indicates that altering the intrinsic promoter activity of luxS affects Salmonella biofilm formation. Conclusively, we synthesized biologically active DPD. Using this chemical compound in combination with genetic approaches opens new avenues in studying AI-2-mediated signaling. 相似文献
79.
Role of the programmed death-1 pathway in regulation of alloimmune responses in vivo 总被引:7,自引:0,他引:7
Sandner SE Clarkson MR Salama AD Sanchez-Fueyo A Domenig C Habicht A Najafian N Yagita H Azuma M Turka LA Sayegh MH 《Journal of immunology (Baltimore, Md. : 1950)》2005,174(6):3408-3415
Programmed death-1 (PD-1), an inhibitory receptor up-regulated on activated T cells, has been shown to play a critical immunoregulatory role in peripheral tolerance, but its role in alloimmune responses is poorly understood. Using a novel alloreactive TCR-transgenic model system, we examined the functions of this pathway in the regulation of alloreactive CD4+ T cell responses in vivo. PD-L1, but not PD-1 or PD-L2, blockade accelerated MHC class II-mismatched skin graft (bm12 (I-Abm12) into B6 (I-Ab)) rejection in a similar manner to CTLA-4 blockade. In an adoptive transfer model system using the recently described anti-bm12 (ABM) TCR-transgenic mice directly reactive to I-Abm12, PD-1 and PD-L1 blockade enhanced T cell proliferation early in the immune response. In contrast, at a later time point preceding accelerated allograft rejection, only PD-L1 blockade enhanced T cell proliferation. In addition, PD-L1 blockade enhanced alloreactive Th1 cell differentiation. Apoptosis of alloantigen-specific T cells was inhibited significantly by PD-L1 but not PD-1 blockade, indicating that PD-1 may not be the receptor for the apoptotic effect of the PD-L1-signaling pathway. Interestingly, the effect of PD-L1 blockade was dependent on the presence of CD4+ CD25+ regulatory T cells in vivo. These data demonstrate a critical role for the PD-1 pathway, particularly PD-1/PD-L1 interactions, in the regulation of alloimmune responses in vivo. 相似文献
80.
Saunders BM Tran S Ruuls S Sedgwick JD Briscoe H Britton WJ 《Journal of immunology (Baltimore, Md. : 1950)》2005,174(8):4852-4859
TNF is critical for immunity against Mycobacterium tuberculosis infection; however, the relative contributions of the soluble and transmembrane forms of TNF in this immunity are unknown. Using memTNF mice, which express only the transmembrane form of TNF, we have addressed this question. Wild-type (WT), TNF-/-, and transmembrane TNF (memTNF) mice were infected with M. tuberculosis by aerosol. TNF-/- mice developed overwhelming infection with extensive pulmonary necrosis and died after only 33 days. memTNF mice, like WT mice, contained bacterial growth for over 16 wk, developed an Ag-specific T cell response, and initially displayed compact granulomas, comprised of both lymphocytes and macrophages. Expression of mRNA for the chemokines CXCL10, CCL3, CCL5, and CCL7 was comparable in both WT and memTNF mice. As the infection progressed, however, the pulmonary lesions in memTNF mice became larger and more diffuse, with increased neutrophil accumulation and necrosis. This was accompanied by increased influx of activated memory T cells into the lungs of memTNF mice. Eventually, these mice succumbed to infection with a mean time to death of 170 days. The expression of memTNF on T cells is functionally important because the transfer of T cells from memTNF, but not TNF-/- mice, into either RAG-/- or TNF-/- mice conferred the same survival advantage on the M. tuberculosis-infected recipient mice, as the transfer of WT T cells. Therefore, memTNF, in the absence of soluble TNF, is sufficient to control acute, but not chronic, M. tuberculosis infection, in part through its expression on T cells. 相似文献