Structures of TGF-ß with betaglycan and the signaling receptors reveal the mechanism whereby betaglycan potentiates receptor complex assembly and signaling.

Betaglycan (BG) is a transmembrane co-receptor of the transforming growth factor-ß (TGF-ß) family of signaling ligands. It is essential for embryonic development and tissue homeostasis and fertility in adults. It functions by enabling binding of the three TGF-ß isoforms to their signaling receptors and is additionally required for inhibin A (InhA) activity. Despite its requirement for the functions of TGF-ßs and InhA in vivo, structural information explaining BG ligand selectivity and its mechanism of action is lacking. Here, we determine the structure of TGF-ß bound both to BG and the signaling receptors, TGFBR1 and TGFBR2. We identify key regions responsible for ligand engagement, which has revealed novel binding interfaces that differ from those described for the closely related co-receptor of the TGF-ß family, endoglin, thus demonstrating remarkable evolutionary adaptation to enable ligand selectivity. Finally, we provide a structural explanation for the hand-off mechanism underlying TGF-ß signal potentiation.

Chaperone BiP controls ER stress sensor Ire1 through interactions with its oligomers.

The complex multistep activation cascade of Ire1 involves changes in the Ire1 conformation and oligomeric state. Ire1 activation enhances ER folding capacity, in part by overexpressing the ER Hsp70 molecular chaperone BiP; in turn, BiP provides tight negative control of Ire1 activation. This study demonstrates that BiP regulates Ire1 activation through a direct interaction with Ire1 oligomers. Particularly, we demonstrated that the binding of Ire1 luminal domain (LD) to unfolded protein substrates not only trigger conformational changes in Ire1-LD that favour the formation of Ire1-LD oligomers but also exposes BiP binding motifs, enabling the molecular chaperone BiP to directly bind to Ire1-LD in an ATP-dependent manner. These transient interactions between BiP and two short motifs in the disordered region of Ire1-LD are reminiscent of interactions between clathrin and another Hsp70, cytoplasmic Hsc70. BiP binding to substrate-bound Ire1-LD oligomers enables unfolded protein substrates and BiP to synergistically and dynamically control Ire1-LD oligomerisation, helping to return Ire1 to its deactivated state when an ER stress response is no longer required.

Synthesis of 13C-methyl-labeled amino acids and their incorporation into proteins in mammalian cells.

Isotopic labeling of methyl-substituted proteinogenic amino acids with 13C has transformed applications of solution-based NMR spectroscopy and allowed the study of much larger and more complex proteins than previously possible with 15N labeling. Procedures are well-established for producing methyl-labeled proteins expressed in bacteria, with efficient incorporation of 13C-methyl labeled metabolic precursors to enable the isotopic labeling of Ile, Val, and Leu methyl groups. Recently, similar methodology has been applied to enable 13C-methyl labeling of Ile, Val, and Leu in yeast, extending the approach to proteins that do not readily fold when produced in bacteria. Mammalian or insect cells are nonetheless preferable for production of many human proteins, yet 13C-methyl labeling using similar metabolic precursors is not feasible as these cells lack the requisite biosynthetic machinery. Herein, we report versatile and high-yielding synthetic routes to 13C methyl-labeled amino acids based on palladium-catalyzed C(sp3)-H functionalization. We demonstrate the efficient incorporation of two of the synthesized amino acids, 13C-γ2-Ile and 13C-γ1,γ2-Val, into human receptor extracellular domains with multiple disulfides using suspension-cultured HEK293 cells. Production costs are reasonable, even at moderate expression levels of 2-3 mg purified protein per liter of medium, and the method can be extended to label other methyl groups, such as 13C-δ1-Ile and 13C-δ1,δ2-Leu. In summary, we demonstrate the cost-effective production of methyl-labeled proteins in mammalian cells by incorporation of 13C methyl-labeled amino acids generated de novo by a versatile synthetic route.

An oncolytic virus-delivered TGFß inhibitor overcomes the immunosuppressive tumor microenvironment.

While checkpoint blockade immunotherapies have widespread success, they rely on a responsive immune infiltrate; as such, treatments enhancing immune infiltration and preventing immunosuppression are of critical need. We previously generated αPD-1 resistant variants of the murine HNSCC model MEER. While entirely αPD-1 resistant, these tumors regress after single dose of oncolytic vaccinia virus (VV). We then generated a VV-resistant MEER line to dissect the immunologic features of sensitive and resistant tumors. While treatment of both tumor types induced immune infiltration and IFNγ, we found a defining feature of resistance was elevation of immunosuppressive cytokines like TGFß, which blunted IFNγ signaling, especially in regulatory T cells. We engineered VV to express a genetically encoded TGFßRII inhibitor. Inhibitor-expressing VV produced regressions in resistant tumor models and showed impressive synergy with checkpoint blockade. Importantly, tumor-specific, viral delivery of TGFß inhibition had no toxicities associated with systemic TGFß/TGFßR inhibition. Our data suggest that aside from stimulating immune infiltration, oncolytic viruses are attractive means to deliver agents to limit immunosuppression in cancer.

The combined action of the intracellular regions regulates FGFR2 kinase activity.

Receptor tyrosine kinases (RTKs) are typically activated through a precise sequence of intracellular phosphorylation events starting with a tyrosine residue on the activation loop (A-loop) of the kinase domain (KD). From this point the mono-phosphorylated enzyme is active, but subject to stringent regulatory mechanisms which can vary dramatically across the different RTKs. In the absence of extracellular stimulation, fibroblast growth factor receptor 2 (FGFR2) exists in the mono-phosphorylated state in which catalytic activity is regulated to allow rapid response upon ligand binding, whilst restricting ligand-independent activation. Failure of this regulation is responsible for pathologic outcomes including cancer. Here we reveal the molecular mechanistic detail of KD control based on combinatorial interactions of the juxtamembrane (JM) and the C-terminal tail (CT) regions of the receptor. JM stabilizes the asymmetric dimeric KD required for substrate phosphorylation, whilst CT binding opposes dimerization, and down-regulates activity. Direct binding between JM and CT delays the recruitment of downstream effector proteins adding a further control step as the receptor proceeds to full activation. Our findings underscore the diversity in mechanisms of RTK oligomerisation and activation.

Receptor tyrosine kinases regulate signal transduction through a liquid-liquid phase separated state.

The recruitment of signaling proteins into activated receptor tyrosine kinases (RTKs) to produce rapid, high-fidelity downstream response is exposed to the ambiguity of random diffusion to the target site. Liquid-liquid phase separation (LLPS) overcomes this by providing elevated, localized concentrations of the required proteins while impeding competitor ligands. Here, we show a subset of phosphorylation-dependent RTK-mediated LLPS states. We then investigate the formation of phase-separated droplets comprising a ternary complex including the RTK, (FGFR2); the phosphatase, SHP2; and the phospholipase, PLCγ1, which assembles in response to receptor phosphorylation. SHP2 and activated PLCγ1 interact through their tandem SH2 domains via a previously undescribed interface. The complex of FGFR2 and SHP2 combines kinase and phosphatase activities to control the phosphorylation state of the assembly while providing a scaffold for active PLCγ1 to facilitate access to its plasma membrane substrate. Thus, LLPS modulates RTK signaling, with potential consequences for therapeutic intervention.

Novel TGFß Inhibitors Ameliorate Oral Squamous Cell Carcinoma Progression and Improve the Antitumor Immune Response of Anti-PD-L1 Immunotherapy.

TGFß is a key regulator of oral squamous cell carcinoma (OSCC) progression, and its potential role as a therapeutic target has been investigated with a limited success. This study evaluates two novel TGFß inhibitors as mono or combinatorial therapy with anti-PD-L1 antibodies (α-PD-L1 Ab) in a murine OSCC model. Immunocompetent C57BL/6 mice bearing malignant oral lesions induced by 4-nitroquinoline 1-oxide (4-NQO) were treated for 4 weeks with TGFß inhibitors mRER (i.p., 50 µg/d) or mmTGFß2-7m (10 µg/d delivered by osmotic pumps) alone or in combination with α-PD-L1 Abs (7× i.p. of 100 µg/72 h). Tumor progression and body weight were monitored. Levels of bioactive TGFß in serum were quantified using a TGFß bioassay. Tissues were analyzed by immunohistology and flow cytometry. Therapy with mRER or mmTGFß2-7m reduced tumor burden (P < 0.05) and decreased body weight loss compared with controls. In inhibitor-treated mice, levels of TGFß in tumor tissue and serum were reduced (P < 0.05), whereas they increased with tumor progression in controls. Both inhibitors enhanced CD8+ T-cell infiltration into tumors and mRER reduced levels of myeloid-derived suppressor cells (P < 0.001). In combination with α-PD-L1 Abs, tumor burden was not further reduced; however, mmTGFß2-7m further reduced weight loss (P < 0.05). The collagen-rich stroma was reduced by using combinatorial TGFß/PD-L1 therapies (P < 0.05), enabling an accelerated lymphocyte infiltration into tumor tissues. The blockade of TGFß signaling by mRER or mmTGFß2-7m ameliorated in vivo progression of established murine OSCC. The inhibitors promoted antitumor immune responses, alone and in combination with α-PD-L1 Abs.

Grb2 binding induces phosphorylation-independent activation of Shp2.

The regulation of phosphatase activity is fundamental to the control of intracellular signalling and in particular the tyrosine kinase-mediated mitogen-activated protein kinase (MAPK) pathway. Shp2 is a ubiquitously expressed protein tyrosine phosphatase and its kinase-induced hyperactivity is associated with many cancer types. In non-stimulated cells we find that binding of the adaptor protein Grb2, in its monomeric state, initiates Shp2 activity independent of phosphatase phosphorylation. Grb2 forms a bidentate interaction with both the N-terminal SH2 and the catalytic domains of Shp2, releasing the phosphatase from its auto-inhibited conformation. Grb2 typically exists as a dimer in the cytoplasm. However, its monomeric state prevails under basal conditions when it is expressed at low concentration, or when it is constitutively phosphorylated on a specific tyrosine residue (Y160). Thus, Grb2 can activate Shp2 and downstream signal transduction, in the absence of extracellular growth factor stimulation or kinase-activating mutations, in response to defined cellular conditions. Therefore, direct binding of Grb2 activates Shp2 phosphatase in the absence of receptor tyrosine kinase up-regulation.

Targeting the Shc-EGFR interaction with indomethacin inhibits MAP kinase pathway signalling.

Receptor tyrosine kinase (RTK)-mediated hyperactivation of the MAPK/Erk pathway is responsible for a large number of pathogenic outcomes including many cancers. Considerable effort has been directed at targeting this pathway with varying degrees of long term therapeutic success. Under non-stimulated conditions Erk is bound to the adaptor protein Shc preventing aberrant signalling by sequestering Erk from activation by Mek. Activated RTK recruits Shc, via its phosphotyrosine binding (PTB) domain (ShcPTB), precipitating the release of Erk to engage in a signalling response. Here we describe a novel approach to inhibition of MAP kinase signal transduction through attempting to preserve the Shc-Erk complex under conditions of activated receptor. A library of existing drug molecules was computationally screened for hits that would bind to the ShcPTB and block its interaction with the RTKs EGFR and ErbB2. The primary hit from the screen was indomethacin, a non-steroidal anti-inflammatory drug. Validation of this molecule in vitro and in cellular efficacy studies in cancer cells provides proof of principle of the approach to pathway down-regulation and a potential optimizable lead compound.

In silico analysis of cytochrome P450 monooxygenases in chronic granulomatous infectious fungus Sporothrix schenckii: Special focus on CYP51.

Sporotrichosis is an emerging chronic, granulomatous, subcutaneous, mycotic infection caused by Sporothrix species. Sporotrichosis is treated with the azole drug itraconazole as ketoconazole is ineffective. It is a well-known fact that azole drugs act by inhibiting cytochrome P450 monooxygenases (P450s), heme-thiolate proteins. To date, nothing is known about P450s in Sporothrix schenckii and the molecular basis of its resistance to ketoconazole. Here we present genome-wide identification, annotation, phylogenetic analysis and comprehensive P450 family-level comparative analysis of S. schenckii P450s with pathogenic fungi P450s, along with a rationale for ketoconazole resistance by S. schenckii based on in silico structural analysis of CYP51. Genome data-mining of S. schenckii revealed 40 P450s in its genome that can be grouped into 32 P450 families and 39 P450 subfamilies. Comprehensive comparative analysis of P450s revealed that S. schenckii shares 11 P450 families with plant pathogenic fungi and has three unique P450 families: CYP5077, CYP5386 and CYP5696 (novel family). Among P450s, CYP51, the main target of azole drugs was also found in S. schenckii. 3D modeling of S. schenckii CYP51 revealed the presence of characteristic P450 motifs with exceptionally large reductase interaction site 2. In silico analysis revealed number of mutations that can be associated with ketoconazole resistance, especially at the channel entrance to the active site. One of possible reason for better stabilization of itraconazole, compared to ketoconazole, is that the more extended molecule of itraconazole may form a hydrogen bond with ASN-230. This in turn may explain its effectiveness against S. schenckii vis-a-vis resistant to ketoconazole. This article is part of a Special Issue entitled: Cytochrome P450 biodiversity and biotechnology, edited by Erika Plettner, Gianfranco Gilardi, Luet Wong, Vlada Urlacher, Jared Goldstone.

Allosteric fine-tuning of the conformational equilibrium poises the chaperone BiP for post-translational regulation.

BiP is the only Hsp70 chaperone in the endoplasmic reticulum (ER) and similar to other Hsp70s, its activity relies on nucleotide- and substrate-controllable docking and undocking of its nucleotide-binding domain (NBD) and substrate-binding domain (SBD). However, little is known of specific features of the BiP conformational landscape that tune BiP to its unique tasks and the ER environment. We present methyl NMR analysis of the BiP chaperone cycle that reveals surprising conformational heterogeneity of ATP-bound BiP that distinguishes BiP from its bacterial homologue DnaK. This unusual poise enables gradual post-translational regulation of the BiP chaperone cycle and its chaperone activity by subtle local perturbations at SBD allosteric 'hotspots'. In particular, BiP inactivation by AMPylation of its SBD does not disturb Hsp70 inter-domain allostery and preserves BiP structure. Instead it relies on a redistribution of the BiP conformational ensemble and stabilization the domain-docked conformation in presence of ADP and ATP.

Identification of Relationships Between Interleukin 15 mRNA and Brain-Derived Neurotrophic Factor II mRNA Levels With Formal Components of Temperament in Asthmatic Patients.

Asthma is a chronic inflammatory and heterogeneous disease developing mostly through allergic inflammation, which modifies the expression of various cytokines and neurotrophins. Previous studies suggest the involvement of interleukin (IL)-15 in the regulation of immune response in asthma. Brain-derived neurotrophic factor (BDNF) II plays an important role as a regulator of development and survival of neurons as well as maintenance of their physiological activity. Chronic stress associated with asthma and elevated IL-15 mRNA and BDNFII mRNA levels may affect the mood and a subjective sensation of dyspnoea-inducing anxiety. Psychopathological variables and numerous cytokine/neurotrophin interactions influence the formation of temperament and strategies of coping with stress. The aim of the study was to identify the role of IL-15 mRNA and BDNFII mRNA expressions and their effect on components of temperament and strategies of coping with stress in asthmatics. A total of 352 subjects (176 healthy volunteers and 176 asthmatic patients) participated in the study. The Formal Characteristic of Behaviour-Temperament Inventory (FCB-TI), Coping Inventory for Stressful Situations (CISS), Beck Depression Inventory, State-Trait Anxiety Inventory, and Borg Rating of Perceived Exertion (RPE) Scale were applied in all the subjects. The expression of IL-15 and BDNFII gene was measured using quantitative real-time polymerase chain reaction (qRT-PCR). Different levels of IL-15 and BDNFII expressions between healthy volunteers and patients were revealed in the study. IL-15 enhanced the BDNFII mRNA expression among patients with bronchial asthma. The depression level negatively correlated with the BDNFII mRNA expression. This neurotrophin modified the temperament variable. BDNFII significantly affected (proportional relationship) the level of briskness in asthmatic patients. BDNFII might influence the level and style of coping with stress (emotion-oriented style). This hypothesis requires further studies on protein functional models. The obtained data confirms the role of IL-15 and BDNFII in the pathomechanisms of depression and formation of selected traits defining the temperament in asthmatics.

Haloperidol, but not olanzapine, may affect expression of PER1 and CRY1 genes in human glioblastoma cell line.

Background: There is barely any evidence of antipsychotic drugs affecting the molecular clockwork in human, yet it is suggested that clock genes are associated with dopaminergic transmission, i.e. the main target of this therapeutics. We decided to verify if haloperidol and olanzapine affect expression of CLOCK, BMAL1, PER1 and CRY1 in a human central nervous system cell line model. Methods: U-87MG human glioblastoma cell line was used as an experimental model. The cells were incubated with or without haloperidol and olanzapine in the concentration of 5 and 20 µM for 24 h. Real-time quantitative polymerase chain reaction with the ΔCT analysis was used to examine the effect of haloperidol and olanzapine on the mRNA expression of the genes. Results: At 5 µM, haloperidol decreased expression of CRY1 almost 20-fold. There was nearly a 1.5-fold increase in expression of PER1. Considering the 20 µM haloperidol concentration and both olanzapine concentrations, no other statistically significant effect was observed. Conclusions: At certain concentration, haloperidol seems to affect expression of particular clock genes in a human central nervous system cell line model, yet mechanism underlying this phenomenon remains elusive.

Coarse-Grained Protein Models and Their Applications.

The traditional computational modeling of protein structure, dynamics, and interactions remains difficult for many protein systems. It is mostly due to the size of protein conformational spaces and required simulation time scales that are still too large to be studied in atomistic detail. Lowering the level of protein representation from all-atom to coarse-grained opens up new possibilities for studying protein systems. In this review we provide an overview of coarse-grained models focusing on their design, including choices of representation, models of energy functions, sampling of conformational space, and applications in the modeling of protein structure, dynamics, and interactions. A more detailed description is given for applications of coarse-grained models suitable for efficient combinations with all-atom simulations in multiscale modeling strategies.

A novel approach to understanding the role of polymorphic forms of the NR3C1 and TGF-ß1 genes in the modulation of the expression of IL-5 and IL-15 mRNA in asthmatic inflammation.

The aim of the present study was to identify polymorphic forms of the nuclear receptor subfamily 3, group C, member 1 (NR3C1) and transforming growth factor ß1 (TGF-ß1) genes and evaluate their impact on the expression levels of interleukin (IL)-5 and IL­15 in asthma. The study was conducted on a control group consisting of 91 people (54 women and 37 men). The patient group consisted of 130 participants (86 women and 44 men). Genotyping was performed by polymerase chain reaction­restriction fragment length polymorphism (PCR­RFLP) and PCR­high resolution melting (HRM) methods. Interleukin expression was measured by reverse transcription­quantitative polymerase chain reaction. The frequency of the polymorphic forms in the analyzed group were observed to be: Tth111I (rs10052957) controls AA 0.0440, AG 0.5714, GG 0.3846, patients AA 0.1538/AG 0.4692, GG 0.3769; ER22/23EK (rs6189 /rs6190) controls AG 0.0556, GG 0.9444, patients AG 0.0385, GG 0.9615; N363S (rs6195) controls AA 0.6444, AG 0.2667, GG 0.0889, patients AA 0.7846, AG 0.1385, GG 0.0769; BclI (rs41423247) controls CC 0.0879, CG 0.5604, GG 0.3516, patients CC 0.1008, CG 0.5736, GG 0.3256; C­509T (rs1800469) controls TT 0.0805, CT 0.6322, CC 0.2874, patients TT 0.1102, CT 0.5669, CC 0.3228. The results indicated that the C­509T single nucleotide polymorphism (SNP) of the TGF-ß1 gene contributed to an increase in the IL­5 mRNA expression levels. The GG genotype of the N363S SNP of the NR3C1 gene was observed to result in an increase in the expression levels of IL­15. The present study indicated that the selected SNPs of the NR3C1 and TGF­ß1 genes demonstrate a regulatory effect on the expression of IL­5 and IL­15. Therefore, genetic variation affects inflammation in asthma and the clinical course of the disease.

Antipsychotic Drugs Differentially Affect mRNA Expression of Genes Encoding the Neuregulin 1-Downstream ErbB4-PI3K Pathway.

BACKGROUND/AIMS: The PIK3CD gene encodes the delta catalytic subunit of phosphoinositide 3-kinase (PI3K), an element of the neuregulin 1-downstream ErbB4-PI3K signaling pathway, which was recently identified as a molecular target for the treatment of schizophrenia. The aim of the study was to examine the effect of haloperidol (HALO), clozapine (CLO), olanzapine (OLA), quetiapine (QUE) and amisulpride (AMI) on the mRNA and protein expression of genes encoding the elements of ErbB4-PI3K pathway, in a human central nervous system cell line. METHODS: The U-87MG human glioblastoma cell line was used as an experimental model. Quantitative polymerase chain reaction was used to examine the expression of mRNA and enzyme-linked immunosorbent assay for protein expression. RESULTS: At concentrations reached in clinical settings in the brain, CLO, as well as OLA and QUE to a lesser extent, but not AMI and probably not HALO, decreased the mRNA expression of PIK3CD. Protein expression of the gene did not confirm the mRNA expression profile. CONCLUSIONS: The tested antipsychotic drugs (APDs) in the U-87MG glioblastoma cell line differentially regulates the mRNA expression of PIK3CD; however, the protein expression does not confirm these findings. The results of the study may help deepen the understanding of the mechanism of action of APDs.

Higher mitochondrial potential and elevated mitochondrial respiration are associated with excessive activation of blood platelets in diabetic rats.

AIMS: The high glucose concentration observed in diabetic patients is a recognized factor of mitochondrial damage in various cell types. Its impact on mitochondrial bioenergetics in blood platelets remains largely vague. The aim of the study was to determine how the metabolism of carbohydrates, which has been impaired by streptozotocin-induced diabetes may affect the functioning of platelet mitochondria. MATERIALS AND METHODS: Diabetes was induced in Sprague Dawley rats by intraperitoneal injection of streptozotocin. Platelet mitochondrial respiratory capacity was monitored as oxygen consumption (high-resolution respirometry). Mitochondrial membrane potential was assessed using a fluorescent probe, JC-1. Activation of circulating platelets was monitored by flow cytometry measuring of the expressions of CD61 and CD62P on a blood platelet surface. To determine mitochondrial protein density in platelets, Western Blot technique was used. KEY FINDINGS: The results indicate significantly elevated mitochondria mass, increased mitochondrial membrane potential (ΔΨm) and enhanced respiration in STZ-diabetic animals, although the respiration control ratios appear to remain unchanged. Higher ΔΨm and elevated mitochondrial respiration were closely related to the excessive activation of circulating platelets in diabetic animals. SIGNIFICANCE: Long-term diabetes can result in increased mitochondrial mass and may lead to hyperpolarization of blood platelet mitochondrial membrane. These alterations may be a potential underlying cause of abnormal platelet functioning in diabetes mellitus and hence, a potential target for antiplatelet therapies in diabetes.

Modeling of protein-peptide interactions using the CABS-dock web server for binding site search and flexible docking.

Protein-peptide interactions play essential functional roles in living organisms and their structural characterization is a hot subject of current experimental and theoretical research. Computational modeling of the structure of protein-peptide interactions is usually divided into two stages: prediction of the binding site at a protein receptor surface, and then docking (and modeling) the peptide structure into the known binding site. This paper presents a comprehensive CABS-dock method for the simultaneous search of binding sites and flexible protein-peptide docking, available as a user's friendly web server. We present example CABS-dock results obtained in the default CABS-dock mode and using its advanced options that enable the user to increase the range of flexibility for chosen receptor fragments or to exclude user-selected binding modes from docking search. Furthermore, we demonstrate a strategy to improve CABS-dock performance by assessing the quality of models with classical molecular dynamics. Finally, we discuss the promising extensions and applications of the CABS-dock method and provide a tutorial appendix for the convenient analysis and visualization of CABS-dock results. The CABS-dock web server is freely available at http://biocomp.chem.uw.edu.pl/CABSdock/.

Long-term untreated streptozotocin-diabetes leads to increased expression and elevated activity of prostaglandin H2 synthase in blood platelets.

In diabetes-related states of chronic hyperglycaemia elevated concentrations of glucose may alter the functioning of platelet enzymes involved in arachidonic acid metabolism, including prostaglandin H2 synthase (cyclooxygenase) (PGHS, COX). Therefore, the principal aim of this study was to assess the effects of experimental chronic hyperglycaemia on platelet PGHS-1 (COX-1) expression and activity. Blood platelet activation and reactivity were assessed in Sprague-Dawley rats with the 5-month streptozotocin (STZ) diabetes. The PGHS-1 abundance in platelets was evaluated with flow cytometry and Western blotting, while its activity monitored using a high resolution respirometry and the peroxidase fluorescent assay. The production of prostaglandin E2 (PGE2) and thromboxane B2 (TXB2) in platelets were assayed immunoenzymatically. Circulating platelets from diabetic were characterised by increased size, elevated 'priming' and altered reactivity, compared to non-diabetic animals. Both Western blot analysis and flow cytometry revealed significantly elevated expressions of platelet PGHS-1 in STZ-diabetic rats (p < 0.05). We also observed significantly elevated platelet PGHS-1-related arachidonic acid metabolism in diabetic vs. non-diabetic animals, with the use of polarographic (p < 0.05) and total activity assay (p < 0.001). Such increases were accompanied by the elevated production of PGE2 (p < 0.001) and TXB2 (p < 0.05) in diabetic animals. The increased PGHS-1-dependent oxygen consumption and the total activity of PGHS-1 in diabetic animals remained very significant (p < 0.001) also upon adjusting for blood platelet PGHS-1 abundance. Therefore, our results further contribute to the explanation of the increased metabolism of arachidonic acid observed in diabetes.

Identification and association of relationships between selected personal and environmental factors and formal components of temperament and strategies of coping with stress in asthmatic patients.

Background: Personal and environmental factors might have an impact on strategies of coping with stress and temperamental traits according to the Regulative Theory of Temperament in asthmatic patients. They can modify the clinical picture, the course of a disease and effectiveness of treatment. Personal variables are key factors in determining formal characteristic of behavior and effective management method in asthmatic patients. Aim of study: The aim of the study was to identify selected personal and environmental factors, as well as factors inducing attacks and asthma exacerbations or maintaining them in a complex of personal traits of patients. Methods: Two hundred and eighty one participants were included in the study. Of this number 122 subjects were healthy volunteers and 159 were asthmatic patients. In all the subjects the authors applied the Formal Characteristic of Behaviour ­ FCZ-KT ­ Temperament Inventory, Coping Inventory for Stressful Situations (CISS), Beck Depression Inventory, State-Trait Anxiety Inventory and Borg Rating of Perceived Exertion (RPE) Scale. Genotyping of polymorphic forms of NR3C1 gene was conducted with PCR-RFLP and PCR-HRM methods. Expression of TGFß1 gene was measured with the use of qRT-PCR. Results: The authors confirmed a significant influence of personal and environmental factors, such as: age, height, body weight, sex, asthma exacerbations, drugs administered by patients, allergy and psychopathological variables on strategies of coping with stress by asthmatic patients (Task-Oriented Coping, Emotion-Oriented Coping, Avoidance-Oriented Coping, distraction seeking, social diversion). Temperamental traits (Briskness, Perseverance, Sensory Sensitivity, Emotional Reactivity, Endurance, Activity) depend on age, sex, body weight, genetic predispositions and they are modified by asthma exacerbations, allergy, drugs administered by patients, depression and anxiety (state and trait). The authors confirmed a correlation between Tth111I polymorphic form of NR3C1 gene and perseverance (p= 0.0450). It was noted that an increase in the TGFß1 expression level led to a decrease in the patients' emotional reactivity (p= 0.0212). Conclusions: Strategies of coping with stress and temperamental traits according to the Regulative Theory of Temperament in asthmatic patients are determined by personal and environmental factors.