Astrocytes in the tempest of multiple sclerosis

Astrocytes are the most abundant cell population within the CNS of mammals. Their glial role is perfectly performed in the healthy CNS as they support functions of neurons. The omnipresence of astrocytes throughout the white and grey matter and their intimate relation with blood vessels of the CNS, as well as numerous immunity-related actions that these cells are capable of, imply that astrocytes should have a prominent role in neuroinflammatory disorders, such as multiple sclerosis (MS). The role of astrocytes in MS is rather ambiguous, as they have the capacity to both stimulate and restrain neuroinflammation and tissue destruction. In this paper we present some of the proved and the proposed functions of astrocytes in neuroinflammation and discuss the effect of MS therapeutics on astrocytes.     

Cross-presentation of HLA class I epitopes from exogenous NY-ESO-1 polypeptides by nonprofessional APCs

NY-ESO-1, a germ cell Ag often detected in tumor tissues, frequently elicits Ab and CD8(+) T cell responses in cancer patients. Overlapping long peptides spanning the NY-ESO-1 sequence have been used to map HLA class I-restricted epitopes recognized by NY-ESO-1-specific CD8(+) T lymphocytes. To address the antigenicity of long peptides, we analyzed two synthetic 30-mer peptides from NY-ESO-1, polypeptides 80-109 and 145-174, for their capacity to be processed by APCs and to stimulate CD8(+) T cells. By incubating APCs with polypeptides at different temperatures or in the presence of protease inhibitors, we found that NY-ESO-1 polypeptides were rapidly internalized by B cells, T2 cells, or PBLs and submitted to cellular proteolytic action to yield nonamer epitopes presented by HLA class I. Polypeptides were also immunogenic in vitro and stimulated the expansion of CD8(+) T cells against naturally processed NY-ESO-1 epitopes in the context of three different HLA class I alleles. Polypeptides can thus serve as exogenous Ags that are cross-presented on HLA class I without requiring the action of professional APCs. These findings support innovative vaccination strategies using NY-ESO-1 polypeptides that would circumvent current limitations of HLA class I peptide vaccination, i.e., HLA eligibility criteria and knowledge of epitope, while allowing for facilitated immunogenicity in the presence of helper epitopes.     

Crystal Structure of the Antitoxin-Toxin Protein Complex RelB-RelE from Methanococcus jannaschii

Here we present the crystal structure of the Methanococcus jannaschii RelE-RelB (RelBE) toxin-antitoxin (TA) protein complex determined by the MIRAS (multiple isomorphous replacement with anomalous signal) method. The genes encoding this TA system are located in the chromosome of this archaeon and involved in stress response. RelE acts as an endoribonuclease that cleaves mRNA on the ribosome, and we compare the RelBE complex to the known structures of other TA systems belonging to this group and to endoribonucleases. M. jannaschii RelBE forms a heterotetramer with the antitoxin in the centre of the complex, a configuration that differs vastly from the heterotetramer structure of the previously published RelBE from another archaeon, Pyrococcus horikoshii. The long N-terminal α-helix of the tightly bound M. jannaschii antitoxin RelB covers the presumed active site of the toxin RelE that is formed by a central β-sheet, a loop on one side and a C-terminal α-helix on the other side. The active site of the M. jannaschii toxin RelE harbours positive charges that are thought to neutralize the negative charges of the substrate mRNA, including Arg62 that was changed to Ser62 by the Escherichia coli expression system, thereby leading to inactive toxin RelE. Comparative studies suggest that Asp43 and His79 are also involved in the activity of the toxin.     

41.8 degrees C whole body hyperthermia as an adjunct to chemotherapy induces prolonged T cell activation in patients with various malignant diseases

Whole body hyperthermia (WBH) has been used as an adjunct to radio-/chemotherapy in patients with various malignant diseases. Although clear evidence is still missing, it has been hypothesized that an activation of the immune system might contribute to the therapeutic effect of WBH. To examine whether a treatment with 60-minute 41.8 degrees C WBH as an adjunct to chemotherapy (WBH-CT) induces an activation of T cells, blood samples were collected at numerous time points before and up to 48 h post-treatment. The aim of this study was to examine the effect of WBH-CT on the expression of a broad range of activation markers on peripheral blood lymphocytes (PBL), on serum cytokines and intracellular cytokine levels in T cells, and the capacity of these cells to proliferate. Immediately after 41.8 degrees C WBH-CT treatment, a drastic increase in peripheral natural killer (NK) cells ( P<0.05) and CD56+ cytotoxic T lymphocytes (CTL; P<0.01) in the patients' peripheral blood was observed. At 5 h post-treatment, the percentages of both effector cell types had returned to baseline levels. This transient phenomenon was accompanied by a short period of reduced T cell activity, indicated by diminished serum levels of soluble interleukin-2 receptors (sIL-2R) at 3 h post-WBH-CT ( P<0.05) and decreased lymphocytic proliferation at the same point in time. This first phase was followed by a marked but short-lived increase in the patients' serum levels of interleukin-6 (IL-6; P<0.01) during the first 5 h following treatment, with a subsequent decrease to baseline levels at 24 h and significantly increased serum levels of tumor necrosis factor-alpha (TNF-alpha) at 0 h ( P<0.01), 3 h ( P<0.05), 5 h ( P<0.05) and 24 h ( P<0.01) post-WBH-CT. The third phase of the immunological consequences of WBH-CT consisted of an increase in the percentage of peripheral cytotoxic T lymphocytes (CTL) expressing CD56, reaching a maximum at 48 h post-WBH ( P<0.01). Furthermore, the percentage of CD4+ T cells expressing the T cell activation marker CD69 increased nearly two-fold over time, reaching its maximum at 48 h ( P<0.05). As an additional marker for T cell activation, serum levels of sIL-2R increased markedly ( P<0.01), reaching maximum levels at the same point in time. Elevated intracellular concentrations of interferon-gamma (IFN-gamma) and/or TNF-alpha in CD8+ T cells were found in 4 out of 5 patients at 24 h post-WBH-CT. Since similar changes were not observed in patients receiving chemotherapy alone, this is the first study to provide evidence for prolonged WBH-CT-induced activation of human T cells.     

The oxidation of alkylaryl sulfides and benzo[b]thiophenes by Escherichia coli cells expressing wild-type and engineered styrene monooxygenase from Pseudomonas putida CA-3

Nine different sulfur-containing compounds were biotransformed to the corresponding sulfoxides by Escherichia coli Bl21(DE3) cells expressing styrene monooxygenase (SMO) from Pseudomonas putida CA-3. Thioanisole was consumed at 83.3 μmoles min^?1 g cell dry weight^?1 resulting mainly in the formation of R-thioanisole sulfoxide with an enantiomeric excess (ee) value of 45 %. The rate of 2-methyl-, 2-chloro- and 2-bromo-thioanisole consumption was 2-fold lower than that of thioanisole. Surprisingly, the 2-methylthioanisole sulfoxide product had the opposite (S) configuration to that of the other 2-substituted thioanisole derivatives and had a higher ee value (84 %). The rate of oxidation of 4-substituted thioanisoles was higher than the corresponding 2-substituted substrates but the ee values of the products were consistently lower (10–23 %). The rate of benzo[b]thiophene and 2-methylbenzo[b]thiophene sulfoxidation was approximately 10-fold lower than that of thioanisole. The ee value of the benzo[b]thiophene sulfoxide could not be determined as the product racemized rapidly. E. coli cells expressing an engineered SMO (SMOeng R3-11) oxidised 2-substituted thioanisoles between 1.8- and 2.8-fold faster compared to cells expressing the wild-type enzyme. SMOeng R3-11 oxidised benzo[b]thiophene and 2-methylbenzo[b]thiophene 10.1 and 5.6 times faster that the wild-type enzyme. The stereospecificity of the reaction catalysed by SMOeng was unchanged from that of the wild type. Using the X-ray crystal structure of the P. putida S12 SMO, it was evident that the entrance of substrates into the SMO active site is limited by the binding pocket bottleneck formed by the side chains of Val-211 and Asn-46 carboxyamide group.     

Structure-based design of 7-azaindole-pyrrolidine amides as inhibitors of 11β-hydroxysteroid dehydrogenase type I

Indole-pyrrolidines were identified as inhibitors of 11β-hydroxysteroid dehydrogenase type 1 (11β-HSD1) by high-throughput screening. Optimisation of the initial hit through structure-based design led to 7-azaindole-derivatives, with the best analogues displaying single digit nanomolar IC(50) potency. The modeling hypotheses were confirmed by solving the X-ray co-crystal structure of one of the lead compounds. These compounds were selective against 11β-hydroxysteroid dehydrogenase type 2 (selectivity ratio >200) and exhibited good inhibition of 11β-HSD1 (IC(50)<1μM) in a cellular model (3T3L1 adipocytes).     

Fragment-based discovery of focal adhesion kinase inhibitors

Chemically diverse fragment hits of focal adhesion kinase (FAK) were discovered by surface plasmon resonance (SPR) screening of our in-house fragment library. Site specific binding of the primary hits was confirmed in a competition setup using a high-affinity ATP-site inhibitor of FAK. Protein crystallography revealed the binding mode of 41 out of 48 selected fragment hits within the ATP-site. Structural comparison of the fragment binding modes with a DFG-out inhibitor of FAK initiated first synthetic follow-up optimization leading to improved binding affinity.     

Gender-related differences in susceptibility to oxidative stress in healthy middle-aged Serbian adults

Gender-related differences in the association between polymorphism of xenobiotic-metabolising enzymes or non-genetic biomarkers and susceptibility to oxidative stress was assessed in healthy middle-aged Serbian adults, by urinary 8-oxo-7,8-dihydro-2'-deoxyguanosine (8-oxodG/creatinine) and total antioxidant status in serum (TAOS). Females were more susceptible to oxidative stress. In both genders, positive predictor of the antioxidative protection was serum triglyceride, while BMI?<25?kg/m² was associated with oxidative stress. Susceptibility to oxidative stress in males was associated with GSTT1*null allele and increased serum iron, but in females, it was decreased serum bilirubin. Early identification of the risk factors could be important in the prevention of oxidative stress-related diseases.     

The sex-specific association of Met62Ile gene polymorphism in P-selectin glycoprotein ligand (PSGL-1) with carotid plaque presence: preliminary study

Atherosclerosis is known as an inflammatory disease in which a recruitment of leukocytes to the endothelium wall represents a preliminary step of the initiation and the development of disease. The P-selectin glycoprotein ligand (PSGL-1) seems to be the major molecule mediating leukocyte–endothelium interactions and leukocyte rolling on stimulated endothelium. There are limited number of studies reporting on association of Met62Ile SNP in PSGL-1 gene and the risk for atherosclerosis. The aim of this study was to analyze possible association of this polymorphism with an advanced carotid atherosclerosis and biochemical markers of inflammation and haemostasis. The 275 patients consecutively admitted for carotid endarterectomy with stenosis >70% and 256 controls of the same ethnic origin were included in the study. The Met62Ile genotypes were determined by PCR RFLP. The Ile/Ile homozygotes had significantly higher CRP compared to the other genotypes in patients. Female patients had Ile allele dose-dependent association with the carotid plaque presence (Met/Met vs. Met/Ile vs. Ile/Ile; OR 1, OR 2.02, CI 1.0–4.08, OR 4.08, CI 1.0–16.81, respectively, p = 0.04). Our results suggest the impact of PSGL-1 Met62Ile polymorphism on inflammation in advanced atherosclerosis. We observed the sex-differential association of Met62Ile with advanced carotid atherosclerosis. Studies in larger and different populations should validate and further examine the suggested role of genetic variations in PSGL-1 with atherosclerosis and thrombosis.     

Patients with solid tumors treated with high-temperature whole body hyperthermia show a redistribution of naive/memory T-cell subtypes

An activation of the immune system might contribute to the therapeutic effect of whole body hyperthermia (WBH) in cancer patients. We explored immune and endocrine responses in patients undergoing high-temperature WBH. Identical parameters were investigated in a separate group of healthy volunteers undergoing physical exercise to rule out effects of sympathetic activation. Lymphocyte subpopulations, lymphocytic expression of a range of adhesion molecules, and serum concentrations of a variety of hormones and cytokines were assessed in cancer patients undergoing high-temperature (60 min at 41.0-41.8 degrees C) WBH (n = 25) and in a separate group of healthy volunteers (n = 10) performing strenuous physical exercise. WBH induced an increase in human growth hormone (hGH), ACTH, and cortisol as well as in TNF-alpha, IL-6, IL-8, and IL-12R. We observed an increase in natural killer (NK) cells and CD56+ NK T cells shortly after initiation of WBH. In contrast, we found a decrease in T cells expressing L-selectin (CD62L) or alpha4beta7 integrin adhesion molecules mediating homing to lymphatic tissues. Accordingly, we observed a decrease in CD45RA+CCR7+ naive and CD45RA-CCR7+ central memory T cells. Numbers of CD45RA-CCR7- memory effector and CD45RA+CCR7 terminally differentiated T cells, on the other hand, remained unchanged. No comparable changes were observed in the group of healthy volunteers. In conclusion, patients with solid tumors treated with WBH show an increase in NK and NK T cells. In a later phase, plasma concentrations of IL-8, hGH, and cortisol increase, correlated with an influx of neutrophils into the peripheral blood. The alterations in T-cell populations suggest that WBH may induce naive and central-memory T cells to enter lymphatic tissue to await antigen exposure and effector T cells to migrate into peripheral tissues to exert their effector function. Although the exercise group may not be an appropriate control to proof the effect of WBH, these changes were not seen in the healthy volunteers performing physical exercise.