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目的:在小胶质细胞与H37Ra结核菌株共培养模型中,探讨NLRP3-Caspase-1通路是否参与到小胶质细胞的损伤过程中,并观察钾离子对该过程的影响。方法:将H37Ra菌株与大鼠小胶质细胞共培养以模拟结核杆菌中枢神经系统感染造成的损伤,并通过real-time PCR,Western blot,ELISA,MTT等相关方法评估该过程中Caspase-1,NLRP3,IL-1β,IL-18等的基因转录及蛋白表达、分泌的变化规律;随后给予细胞外高钾干预,观察其对该模型中NLRP3-Caspase-1相关通路的影响。结果:通过小胶质细胞与H37Ra共培养:(1)小胶质细胞中NLRP3,Caspase-1,IL-1β及IL-18等的转录,表达及活化较前明显增加;(2)在应用细胞外高钾干预后,小胶质细胞中活性Caspase-1明显减少,同时其下游的活性IL-1β、IL-18产生及分泌也明显减少。结论:小胶质细胞与H37Ra共培养后,NLRP3-Caspase-1信号通路被激活,而通过细胞外高钾的干预能够抑制该过程中Caspase-1的活化,以及下游的IL-1β、IL-18的产生及分泌。  相似文献   
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Hsp90 requires cochaperone Cdc37 to load its clients to the Hsp90 superchaperone complex. The purpose of this study was to utilize split Renilla luciferase protein fragment-assisted complementation (SRL-PFAC) bioluminescence to study the full-length human Hsp90-Cdc37 complex and to identity critical residues and their contributions for Hsp90/Cdc37 interaction in living cells. SRL-PFAC showed that full-length human Hsp90/Cdc37 interaction restored dramatically high luciferase activity through Hsp90-Cdc37-assisted complementation of the N and C termini of luciferase (compared with the set of controls). Immunoprecipitation confirmed that the expressed fusion proteins (NRL-Hsp90 and Cdc37-CRL) preserved their ability to interact with each other and also with native Hsp90 or Cdc37. Molecular dynamic simulation revealed several critical residues in the two interaction patches (hydrophobic and polar) at the interface of Hsp90/Cdc37. Mutagenesis confirmed the critical residues for Hsp90-Cdc37 complex formation. SRL-PFAC bioluminescence evaluated the contributions of these critical residues in Hsp90/Cdc37 interaction. The results showed that mutations in Hsp90 (Q133A, F134A, and A121N) and mutations in Cdc37 (M164A, R167A, L205A, and Q208A) reduced the Hsp90/Cdc37 interaction by 70–95% as measured by the resorted luciferase activity through Hsp90-Cdc37-assisted complementation. In comparison, mutations in Hsp90 (E47A and S113A) and a mutation in Cdc37 (A204E) decreased the Hsp90/Cdc37 interaction by 50%. In contrast, mutations of Hsp90 (R46A, S50A, C481A, and C598A) and mutations in Cdc37 (C54S, C57S, and C64S) did not change Hsp90/Cdc37 interactions. The data suggest that single amino acid mutation in the interface of Hsp90/Cdc37 is sufficient to disrupt its interaction, although Hsp90/Cdc37 interactions are through large regions of hydrophobic and polar interactions. These findings provides a rationale to develop inhibitors for disruption of the Hsp90/Cdc37 interaction.  相似文献   
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《Cytokine》2015,76(2):389-402
The aim of the study was to characterize and to quantify peripheral and tissue. IL-35— and IL-37—producing cells in Inflammatory Bowel Disease (IBD) patients. We studied a total of 38 active UC, 31 inactive UC, 17 active CD, and 13 inactive CD and 50 non-inflamed tissues as control group. Gene expression was measured by real time polymerase chain reaction (RT-PCR) and protein expression was evaluated in tissue by immunohistochemistry and in peripheral blood mononuclear cells by flow cytometry. Higher levels of IL-35 was produced by intestinal regulatory B cells and circulating regulatory CD4+ and CD8+ T cells in active vs. inactive disease or healthy donors (P < 0.05). The IL-37 was conspicuously synthesized by circulating B cells, active natural killer cells and monocytes. These results suggest that down-regulation of inflammation in active IBD patients might be based on the increased expression of IL-35 and IL-37.  相似文献   
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In previous work, a strongly stabilized variant of the β1 domain of streptococcal protein G (Gβ1) was obtained by an in vitro selection method. This variant, termed Gβ1-M2, contains the four substitutions E15V, T16L, T18I, and N37L. Here we elucidated the molecular basis of the observed strong stabilizations. The contributions of these four residues were analyzed individually and in various combinations, additional selections with focused Gβ1 gene libraries were performed, and the crystal structure of Gβ1-M2 was determined. All single substitutions (E15V, T16L, T18I, and N37L) stabilize wild-type Gβ1 by contributions of between 1.6 and 6.0 kJ mol− 1 (at 70 °C). Hydrophobic residues at positions 16 and 37 provide the major contribution to stabilization by enlarging the hydrophobic core of Gβ1. They also increase the tendency to form dimers, as shown by dependence on the concentration of apparent molecular mass in analytical ultracentrifugation, by concentration-dependent stability, and by a strongly increased van't Hoff enthalpy of unfolding. The 0.88-Å crystal structure of Gβ1-M2 and NMR measurements in solution provide the explanation for the observed dimer formation. It involves a head-to-head arrangement of two Gβ1-M2 molecules via six intermolecular hydrogen bonds between the two β strands 2 and 2′ and an adjacent self-complementary hydrophobic surface area, which is created by the T16L and N37L substitutions and a large 120° rotation of the Tyr33 side chain. This removal of hydrophilic groups and the malleability of the created hydrophobic surface provide the basis for the dimer formation of stabilized Gβ1 variants.  相似文献   
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Worldwide bacterial resistance to traditional antibiotics has drawn much research attention to naturally occurring antimicrobial peptides (AMPs) owing to their potential as alternative antimicrobials. Structural studies of AMPs are essential for an in-depth understanding of their activity, mechanism of action, and in guiding peptide design. Two-dimensional solution proton NMR spectroscopy has been the major tool. In this article, we describe the applications of natural abundance 13C NMR spectroscopy that provides complementary information to 2D 1H NMR. The correlation of 13Cα secondary shifts with both 3D structure and heteronuclear 15N NOE values indicates that natural abundance carbon chemical shifts are useful probes for backbone structure and dynamics of membrane peptides. Using human LL-37-derived peptides (GF-17, KR-12, and RI-10), as well as amphibian antimicrobial and anticancer peptide aurein 1.2 and its analog LLAA, as models, we show that the cross peak intensity plots of 2D 1H-13Cα HSQC spectra versus residue number present a wave-like pattern (HSQC wave) where key hydrophobic residues of micelle-bound peptides are located in the troughs with weaker intensities, probably due to fast exchange between the free and bound forms. In all the cases, the identification of aromatic phenylalanines as a key membrane-binding residue is consistent with previous intermolecular Phe-lipid NOE observations. Furthermore, mutation of one of the key hydrophobic residues of KR-12 to Ala significantly reduced the antibacterial activity of the peptide mutants. These results illustrate that natural abundance heteronuclear-correlated NMR spectroscopy can be utilized to probe backbone structure and dynamics, and perhaps to map key membrane-binding residues of peptides in complex with micelles. 1H-13Cα HSQC wave, along with other NMR waves such as dipolar wave and chemical shift wave, offers novel insights into peptide-membrane interactions from different angles.  相似文献   
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Alexander disease (AxD) is a rare and fatal neurodegenerative disorder caused by mutations in the gene encoding glial fibrillary acidic protein (GFAP). In this report, a mouse model of AxD (GFAPTg;Gfap+/R236H) was analyzed that contains a heterozygous R236H point mutation in murine Gfap as well as a transgene with a GFAP promoter to overexpress human GFAP. Using label-free quantitative proteomic comparisons of brain tissue from GFAPTg;Gfap+/R236H versus wild-type mice confirmed upregulation of the glutathione metabolism pathway and indicated proteins were elevated in the peroxisome proliferator-activated receptor (PPAR) signaling pathway, which had not been reported previously in AxD. Relative protein-level differences were confirmed by a targeted proteomics assay, including proteins related to astrocytes and oligodendrocytes. Of particular interest was the decreased level of the oligodendrocyte protein, 2-hydroxyacylsphingosine 1-beta-galactosyltransferase (Ugt8), since Ugt8-deficient mice exhibit a phenotype similar to GFAPTg;Gfap+/R236H mice (e.g., tremors, ataxia, hind-limb paralysis). In addition, decreased levels of myelin-associated proteins were found in the GFAPTg;Gfap+/R236H mice, consistent with the role of Ugt8 in myelin synthesis. Fabp7 upregulation in GFAPTg;Gfap+/R236H mice was also selected for further investigation due to its uncharacterized association to AxD, critical function in astrocyte proliferation, and functional ability to inhibit the anti-inflammatory PPAR signaling pathway in models of amyotrophic lateral sclerosis (ALS). Within Gfap+ astrocytes, Fabp7 was markedly increased in the hippocampus, a brain region subjected to extensive pathology and chronic reactive gliosis in GFAPTg;Gfap+/R236H mice. Last, to determine whether the findings in GFAPTg;Gfap+/R236H mice are present in the human condition, AxD patient and control samples were analyzed by Western blot, which indicated that Type I AxD patients have a significant fourfold upregulation of FABP7. However, immunohistochemistry analysis showed that UGT8 accumulates in AxD patient subpial brain regions where abundant amounts of Rosenthal fibers are located, which was not observed in the GFAPTg;Gfap+/R236H mice.  相似文献   
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