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Endogenous Inhibitor (endogenous + inhibitor)
Selected AbstractsEFFECT OF FROZEN TEMPERATURE AND STORAGE TIME ON CALPAINS, CATHEPSINS (B, B + L, H AND D) AND THEIR ENDOGENOUS INHIBITORS IN GOAT MUSCLESJOURNAL OF FOOD BIOCHEMISTRY, Issue 2 2006N.S. NAGARAJ ABSTRACT The effects of frozen storage on the biochemical properties of myofibrils, muscle proteinases (cathepsins and calpains) and their endogenous inhibitors were investigated. Longissimus dorsi, biceps femoris, semimembranosus and semitendinosus muscles from goat were frozen (,15C) and studied up to 120 days. The results showed that the percentage change in sarcomere length was 8.4,13.1. The calpain activity was determined after separation on a diethylaminoethyl,Sephacel column (Sigma, St. Louis, MO). Significantly greater percentage of calpain II activity was recovered when compared to calpain I. There was a 15,25% loss in calpastatin inhibitory activity, and the cystatin level fell by 11,16% after 80 days. Cathepsin B, B + L, H and D were very stable when compared to calpains. The calcium concentration may also be the factor for calpain activation. The sodium dodecyl sulfate,polyacrylamide gel electrophoresis result showed the appearance of 55 kDa components. It was concluded that calpains, not cathepsins, play an important role in the proteolysis of myofibrillar proteins at the freezing temperature. [source] Myoblast attachment and spreading are regulated by different patterns by ubiquitous calpainsCYTOSKELETON, Issue 4 2006Germain Mazčres Abstract The calcium-dependent proteolytic system is a large family of well-conserved ubiquitous and tissue-specific proteases, known as calpains, and an endogenous inhibitor, calpastatin. Ubiquitous calpains are involved in many physiological phenomena, such as the cell cycle, muscle cell differentiation, and cell migration. This study investigates the regulation of crucial steps of cell motility, myoblast adhesion and spreading, by calpains. Inhibition of each ubiquitous calpain isoform by antisense strategy pinpointed the involvement of each of these proteases in myoblast adhesion and spreading. Moreover, the actin cytoskeleton and microtubules were observed in transfected cells, demonstrating that each ubiquitous calpain could be involved in the actin fiber organization. C2C12 cells with reduced ,- or m-calpain levels have a rounded morphology and disorganized stress fibers, but no modification in the microtubule cytoskeleton. Antisense strategy directed against MARCKS, a calpain substrate during C2C12 migration, showed that this protein could play a role in stress fiber polymerization. A complementary proteomic analysis using C2C12 cells over-expressing calpastatin indicated that two proteins were under-expressed, while six, which are involved in the studied phenomena, were overexpressed after calpain inhibition. The possible role of these proteins in adhesion, spreading, and migration was discussed. Cell Motil. Cytoskeleton 63: 2006. © 2006 Wiley-Liss, Inc. [source] Attenuation of retinal vascular development and neovascularization in transgenic mice over-expressing thrombospondin-1 in the lensDEVELOPMENTAL DYNAMICS, Issue 7 2006Zhifeng Wu Abstract Thrombospondin-1 (TSP1) is an endogenous inhibitor of angiogenesis and induces endothelial cell (EC) apoptosis. To study the role TSP1 plays during vascular development and neovascularization, we assessed the effects of ectopic TSP1 expression in the lens on retinal vascularization in transgenic mice. The TSP1 over-expressing mice showed abnormalities in the development of retinal vasculature. There was a dramatic decrease in the density of superficial and deep vascular plexuses of the retina in transgenic mice. The retinal vessels in TSP1 transgenic mice also appeared nonuniform and abnormal in maturation. We detected an increase in the number of EC undergoing apoptosis, which was compensated, in part, by an increase in cell proliferation in retinal vasculature of TSP1 transgenic mice. The TSP1 transgenic mice also exhibited increased levels of vessel obliteration and a limited preretinal neovascularization during oxygen-induced ischemic retinopathy (OIR). Our results indicate increased expression of TSP1 attenuates normal retinal vascularization and preretinal neovascularization during OIR. Therefore, modulation of TSP1 expression may provide an effective mechanism for regulation of ocular angiogenesis. Developmental Dynamics 235:1908,1920, 2006. © 2006 Wiley-Liss, Inc. [source] 8-isoprostane increases scavenger receptor A and matrix metalloproteinase activity in THP-1 macrophages, resulting in long-lived foam cellsEUROPEAN JOURNAL OF CLINICAL INVESTIGATION, Issue 7 2004H. Scholz Abstract Background, Oxidative stress is a key factor in atherogenesis, in which it is closely associated with the inflammation and formation of bioactive lipids. Although 8-isoprostane is regarded as a reliable marker of oxidative stress in vivo, the pathogenic role of this F2 -isoprostane in atherogenesis is far from clear. Based on the important role of foam cells in the initiation and progression of atherosclerosis we hereby examined the ability of 8-isoprostane to modulate oxidized (ox)LDL-induced foam cell formation and the function of these cells, particularly focusing on the effect on matrix degradation. Methods and results, 8-isoprostane (10 µM) augmented the oxLDL-induced (20 µg mL,1) lipid accumulation of THP-1 macrophages evaluated by Oil-Red-O staining and lipid mass quantification (colourimetric assay). Additionally, 8-isoprostane induced the expression of the scavenger receptor A type 1 (MSR-1) [mRNA and protein level], assessed by RT-PCR and Western blotting, respectively. Moreover, 8-isoprostane counteracted the oxLDL-induced apoptosis of these cells, involving both mitochondrial-protective and caspase-suppressive mechanisms. Along with these changes, 8-isoprostane increased the oxLDL-induced gene expression of matrix metalloproteinase (MMP)-9 and its endogenous inhibitor [i.e. tissue inhibitor of MMP (TIMP)-1] accompanied by enhanced total MMP activity. Conclusions, We show that 8-isoprostane increases foam cell formation at least partly by enhancing MSR-1 expression and by inhibiting apoptosis of these cells, inducing long-lived foam cells with enhanced matrix degrading capacity. Our findings further support a role for 8-isoprostane not only as a marker of oxidative stress in patients with atherosclerotic disorders, but also as a mediator in atherogenesis and plaque destabilization. [source] BJ46a, a snake venom metalloproteinase inhibitorFEBS JOURNAL, Issue 10 2001Isolation, characterization, cloning, insights into its mechanism of action Fractionation of the serum of the venomous snake Bothrops jararaca with (NH4)2SO4, followed by phenyl-Sepharose and C4 -reversed phase chromatographies, resulted in the isolation of the anti-hemorrhagic factor BJ46a. BJ46a is a potent inhibitor of the SVMPs atrolysin C (class P-I) and jararhagin (P-III) proteolytic activities and B. jararaca venom hemorrhagic activity. The single-chain, acidic (pI 4.55) glycoprotein has a molecular mass of 46 101 atomic mass units determined by MALDI-TOF MS and 79 kDa by gel filtration and dynamic laser light scattering, suggesting a homodimeric structure. mRNA was isolated from the liver of one specimen and transcribed into cDNA. The cDNA pool was amplified by PCR, cloned into a specific vector and used to transform competent cells. Clones containing the complete coding sequence for BJ46a were isolated. The deduced protein sequence was in complete agreement with peptide sequences obtained by Edman degradation. BJ46a is a 322-amino-acid protein containing four putative N-glycosylation sites. It is homologous to the proteinase inhibitor HSF (member of the fetuin family, cystatin superfamily) isolated from the serum of the snake Trimeresurus flavoviridis, having 85% sequence identity. This is the first report of a complete cDNA sequence for an endogenous inhibitor of snake venom metalloproteinases (SVMPs). The sequence reveals that the only proteolytic processing required to obtain the mature protein is the cleavage of the signal peptide. Gel filtration analyses of the inhibitory complexes indicate that inhibition occurs by formation of a noncovalent complex between BJ46a and the proteinases at their metalloproteinase domains. Furthermore, the data shows that the stoichiometry involved in this interaction is of one inhibitor monomer to two enzyme molecules, suggesting an interesting mechanism of metalloproteinase inhibition. [source] BRCA1-IRIS activates cyclin D1 expression in breast cancer cells by downregulating the JNK phosphatase DUSP3/VHRINTERNATIONAL JOURNAL OF CANCER, Issue 1 2007Lu Hao Abstract Cyclin D1 plays an important role in cell cycle progression. In breast cancer, Cyclin D1 expression is deregulated by several mechanisms. We previously showed that in breast cancer cells, overexpression of BRCA1-IRIS induces Cyclin D1 overexpression and increases cell proliferation. BRCA1-IRIS alone or in complex with steroid receptor co-activators was targeted to the cyclin D1 promoter pre-bound by the c-Jun/AP1 and activated its transcription, which could explain the co-overexpression of BRCA1-IRIS and Cyclin D1 in breast cancer cells coupled with their increased proliferation. We report here an alternate or a complementary pathway by which BRCA1-IRIS activates Cyclin D1 expression. BRCA1-IRIS overexpression decreases the expression of the dual specificity phosphatase, DUSP3/VHR, an endogenous inhibitor of several MAPKs, including c-Jun N-terminal kinase. Although, the mechanism by which BRCA1-IRIS overexpression accomplishes that is not yet known, it is sufficient to induce Cyclin D1 overexpression in a human mammary epithelial cell model. Cyclin D1 overexpression could be blocked by co-overexpression of VHR in those cells. Furthermore, in 2 breast cancer cell lines that overexpress both BRCA1-IRIS and Cyclin D1 (MCF-7 and SKBR3) depletion of BRCA1-IRIS by RNA interference attenuated the expression of Cyclin D1 by elevating the expression level of VHR. These data demonstrate a critical role for BRCA1-IRIS in human breast cancer cell-cycle control and suggest that deregulated expression of BRCA1-IRIS is likely to reduce dependence on normal physiological growth stimuli, thereby providing a growth advantage to tumor cells and a potential mechanism of resistance to endocrine therapy. © 2007 Wiley-Liss, Inc. [source] Thrombospondin-1 as an endogenous inhibitor of angiogenesis and tumor growthJOURNAL OF CELLULAR AND MOLECULAR MEDICINE, Issue 1 2002Jack Lawler Thrombospondin-1 (TSP-1) is a matricellular glycoprotein that influences cellular phenotype and the structure of the extracellular matrix. These effects are important components of the tissue remodeling that is associated with angiogenesis and neoplasia. The genetic mutations in oncogenes and tumor suppressor genes that occur within tumor cells are frequently associated with decreased expression of TSP-1. However, the TSP-1 that is produced by stromal fibroblasts, endothelial cells and immune cells suppresses tumor progression. TSP-1 inhibits angiogenesis through direct effects on endothelial cell migration and survival and through indirect effects on growth factor mobilization. TSP-1 that is present in the tumor microenvironment also acts to suppress tumor cell growth through activation of transforming growth factor , in those tumor cells that are responsive to TGF,. In this review, the molecular basis for the role of TSP-1 in the inhibition of tumor growth and angiogenesis is summarized. [source] Thioredoxin interacting protein (TXNIP) induces inflammation through chromatin modification in retinal capillary endothelial cells under diabetic conditionsJOURNAL OF CELLULAR PHYSIOLOGY, Issue 1 2009Lorena Perrone Chronic hyperglycemia and activation of receptor for advanced glycation end products (RAGE) are known risk factors for microvascular disease development in diabetic retinopathy. Thioredoxin-interacting protein (TXNIP), an endogenous inhibitor of antioxidant thioredoxin (TRX), plays a causative role in diabetes and its vascular complications. Herein we investigate whether HG and RAGE induce inflammation in rat retinal endothelial cells (EC) under diabetic conditions in culture through TXNIP activation and whether epigenetic mechanisms play a role in inflammatory gene expression. We show that RAGE activation by its ligand S100B or HG treatment of retinal EC induces the expression of TXNIP and inflammatory genes such as Cox2, VEGF-A, and ICAM1. TXNIP silencing by siRNA impedes RAGE and HG effects while stable over-expression of a cDNA for human TXNIP in EC elevates inflammation. p38 MAPK-NF-,B signaling pathway and histone H3 lysine (K) nine modifications are involved in TXNIP-induced inflammation. Chromatin immunoprecipitation (ChIP) assays reveal that TXNIP over-expression in EC abolishes H3K9 tri-methylation, a marker for gene inactivation, and increases H3K9 acetylation, an indicator of gene induction, at proximal Cox2 promoter bearing the NF-,B-binding site. These findings have important implications toward understanding the molecular mechanisms of ocular inflammation and endothelial dysfunction in diabetic retinopathy. J. Cell. Physiol. 221: 262,272, 2009. © 2009 Wiley-Liss, Inc [source] MMP-2, TIMP-2 and MT1-MMP are differentially expressed in lesional skin of melanocytic nevi and their expression is modulated by UVB-lightJOURNAL OF CUTANEOUS PATHOLOGY, Issue 7 2002S. Krengel Background:, In malignant melanoma, recent studies have demonstrated an important role of matrix-metalloproteinase 2 (MMP-2), its co-activating enzyme membrane-type matrix-metalloproteinase 1 (MT1-MMP), and the endogenous inhibitor of MMP-2, tissue-inhibitor of matrix metalloproteinase 2 (TIMP-2). Melanocytic nevi are benign neoplasms of the melanocytic lineage, but may exhibit dysplastic features that can be difficult to distinguish from early stage melanoma. As shown in earlier studies, nevi show important morphological and phenotypical changes in response to ultraviolet light (UVB) irradiation. Objective:, To clarify the role of MMP-2, TIMP-2 and MT1-MMP in UVB-irradiated vs. non-irradiated melanocytic nevi. Methods:, Immunohistochemical comparison of the MMP-2, TIMP-2 and MT1-MMP expression pattern. Results:, MMP-2 is expressed by lesional keratinocytes and its expression is up-regulated by UVB-irradiation. MMP-2 expression was not observed in melanocytic cells. TIMP-2, by contrast, is predominantly expressed by melanocytic nevus cells, and its expression is in part down-regulated by UVB-irradiation. MT1-MMP is expressed by basal keratinocytes and to a weaker extent by melanocytic nevus cells. Conclusions:, MMP-2 expression by keratinocytes in nevi probably represents the result of activation of keratinocyte turnover in lesional epidermis. MMP-2 could play a role in the downward movement of junctional nevus cells into the dermis. The reduction of TIMP-2 expression in melanocytic cells by UV-light together with the enhanced expression of MMP-2 in the adjacent epidermis may promote basement membrane degradation. The expression pattern of MT1-MMP in close proximity to epithelial,mesenchymal interfaces underlines the synergistic role of MT1-MMP in this process. [source] Lifeguard/neuronal membrane protein 35 regulates Fas ligand-mediated apoptosis in neurons via microdomain recruitmentJOURNAL OF NEUROCHEMISTRY, Issue 1 2007Miriam Fernández Abstract Fas ligand (FasL)-receptor system plays an essential role in regulating cell death in the developing nervous system, and it has been implicated in neurodegenerative and inflammatory responses in the CNS. Lifeguard (LFG) is a protein highly expressed in the hippocampus and the cerebellum, and it shows a particularly interesting regulation by being up-regulated during postnatal development and in the adult. We show that over-expression of LFG protected cortical neurons from FasL-induced apoptosis and decreased caspase-activation. Reduction of endogenous LFG expression by small interfering RNA sensitized cerebellar granular neurons to FasL-induced cell death and caspase-8 activation, and also increased sensitivity of cortical neurons. In differentiated cerebellar granular neurons, protection from FasL-induced cell death could be attributed exclusively to LFG and appears to be independent of FLICE inhibitor protein. Thus, LFG is an endogenous inhibitor of FasL-mediated neuronal death and it mediates the FasL resistance of CNS differentiated neurons. Finally, we also demonstrate that LFG is detected in lipid rafts microdomains, where it may interact with Fas receptor and regulate FasL-activated signaling pathways. [source] Embryonic gene expression and pro-protein processing of proSAAS during rodent developmentJOURNAL OF NEUROCHEMISTRY, Issue 6 2005Daniel J. Morgan Abstract In vitro assays have demonstrated that peptides derived from the recently,identified proSAAS precursor inhibit prohormone convertase 1 (PC1) suggesting that this novel peptide may function as an endogenous inhibitor of PC1. To further understand the role of proSAAS in vivo, we have investigated the expression of proSAAS mRNA and processing of proSAAS during pre- and early postnatal rodent development. In situ hybridization showed that, by embryonic day 12.5 (e12.5) in the rat, proSAAS mRNA was present in essentially all differentiating neurons in the mantle layer of the myelencephalon, metencephalon, diencephalon, spinal cord and several sympathetic ganglia. During later stages of prenatal development, widespread proSAAS expression continues in post-mitotic neurons of both the CNS and PNS and begins in endocrine cells of the anterior and intermediate pituitary. Although proSAAS expression overlaps with PC1 in several regions, its overall expression pattern is significantly more extensive, suggesting that proSAAS may be multifunctional during development. Processed forms of proSAAS are present by at least mid-gestation with marked accumulation of two C-terminal forms, comprising the PC1 inhibitory fragment of proSAAS. [source] Calpain-mediated degradation of G-substrate plays a critical role in retinal excitotoxicity for amacrine cellsJOURNAL OF NEUROSCIENCE RESEARCH, Issue 6 2009Toru Nakazawa Abstract The role of neuronal N-methyl-D-aspartate (NMDA) receptor-mediated intracellular signaling has been elucidated in both physiological and pathological conditions. However, the details of relative vulnerability for excitotoxicity remain unknown. Retinal excitotoxicity is involved in various diseases leading to irreversible blindness. Here, we used the visual system and explored the mechanistic details of the NMDA-elicited intracellular events, especially in the amacrine cells, which are the most vulnerable type of neuron in the retina. G-substrate, a specific substrate of cyclic guanosine 3,,5,-monophosphate (cGMP)-dependent protein kinase, is colocalized with amacrine cells and acts as an endogenous inhibitor of protein phosphatase. To elucidate how G-substrate was involved in NMDA-induced amacrine cell death, the immunohistochemical analysis with G-substrate antibody was performed following NMDA injury. In vivo, NMDA immediately decreased G-substrate immunoreactivity, and the suppression of calpain activation using ALLN or calpain III, an inhibitor of calpain, blocked this decrease. In vitro, degraded fragments of G-substrate were detected within 10 min after coincubation of G-substrate and calpain. Moreover, G-substrate knockout (G-substrate,/,) mice were more susceptible to NMDA injury than wild-type mice. ALLN did not have a neuroprotective effect in G-substrate,/, mice. These data strongly suggest that calpain-mediated loss of G-substrate represents an important mechanism contributing to NMDA-induced amacrine cell death. © 2008 Wiley-Liss, Inc. [source] Folding transitions in calpain activator peptides studied by solution NMR spectroscopyJOURNAL OF PEPTIDE SCIENCE, Issue 6 2009Orsolya Toke Abstract Calpastatin, the endogenous inhibitor of calpain, a cysteine protease in eukaryotic cells, is an intrinsically unstructured protein, which upon binding to the enzyme goes through a conformational change. Peptides calpA (SGKSGMDAALDDLIDTLGG) and calpC (SKPIGPDDAIDALSSDFTS), corresponding to the two conserved subdomains of calpastatin, are known to activate calpain and increase the Ca2+ sensitivity of the enzyme. Using solution NMR spectroscopy, here we show that calpA and calpC are disordered in water but assume an ,-helical conformation in 50% CD3OH. The position and length of the helices are in agreement with those described in the literature for the bound state of the corresponding segments of calpastatin suggesting that the latter might be structurally primed for the interaction with its target. According to our data, the presence of Ca2+ induces a backbone rearrangement in the peptides, an effect that may contribute to setting the fine conformational balance required for the interaction of the peptides with calpain. Copyright © 2009 European Peptide Society and John Wiley & Sons, Ltd. [source] Thioredoxin system inhibitors as mediators of apoptosis for cancer therapyMOLECULAR NUTRITION & FOOD RESEARCH (FORMERLY NAHRUNG/FOOD), Issue 1 2009Kathryn F. Tonissen Abstract The thioredoxin (Trx) system is a major antioxidant system integral to maintaining the intracellular redox state. It contains Trx, a redox active protein, which regulates the activity of various enzymes including those that function to counteract oxidative stress within the cell. Trx can also scavenge reactive oxygen species (ROS) and directly inhibits proapoptotic proteins such as apoptosis signal-regulating kinase 1 (ASK1). The oxidized form of Trx is reduced by thioredoxin reductase (TrxR). The cytoplasm and mitochondria contain equivalent Trx systems and inhibition of either system can lead to activation of apoptotic signaling pathways. There are a number of inhibitors with chemotherapy applications that target either Trx or TrxR to induce apoptosis in cancer cells. Suberoylanilide hydroxamic acid (SAHA) is effective against many cancer cells and functions by up-regulating an endogenous inhibitor of Trx. Other compounds target the selenocysteine-containing active site of TrxR. These include gold compounds, platinum compounds, arsenic trioxide, motexafin gadolinium, nitrous compounds, and various flavonoids. Inhibition of TrxR leads to an accumulation of oxidized Trx resulting in cellular conditions that promote apoptosis. In addition, some compounds also convert TrxR to a ROS generating enzyme. The role of Trx system inhibitors in cancer therapy is discussed in this review. [source] Recombinant C1 inhibitor in brain ischemic injury,ANNALS OF NEUROLOGY, Issue 3 2009Raffaella Gesuete BD Objective C1 inhibitor (C1-INH) is an endogenous inhibitor of complement and kinin systems. We have explored the efficacy and the therapeutic window of the recently available human recombinant (rh) C1-INH on ischemic brain injury and investigated its mechanism of action in comparison with that of plasma-derived (pd) C1-INH. Methods rhC1-INH was administered intravenously to C57Bl/6 mice undergoing transient or permanent ischemia, and its protective effects were evaluated by measuring infarct volume and neurodegeneration. The binding profiles of rhC1-INH and pdC1-INH were assessed in vitro using surface plasmon resonance. Their localization in the ischemic brain tissue was determined by immunohistochemistry and confocal analysis. The functional consequences of rhC1-INH and pdC1-INH administration on complement activation were analyzed by enzyme-linked immunosorbent assay on plasma samples. Results rhC1-INH markedly reduced cerebral damage when administered up to 18 hours after transient ischemia and up to 6 hours after permanent ischemia, thus showing a surprisingly wide therapeutic window. In vitro rhC1-INH bound mannose-binding lectin (MBL), a key protein in the lectin complement pathway, with high affinity, whereas pdC1-INH, which has a different glycosylation pattern, did not. In the ischemic brain, rhC1-INH was confined to cerebral vessels, where it colocalized with MBL, whereas pdC1-INH diffused into the brain parenchyma. In addition, rhC1-INH was more active than pdC1-INH in inhibiting MBL-induced complement activation. Interpretation rhC1-INH showed a surprisingly wider time window of efficacy compared with the corresponding plasmatic protein. We propose that the superiority of rhC1-INH is due to its selective binding to MBL, which emerged as a novel target for stroke treatment. Ann Neurol 2009;66:332,342 [source] Glucocorticoid-induced leucine zipper is an endogenous antiinflammatory mediator in arthritisARTHRITIS & RHEUMATISM, Issue 9 2010Elaine Beaulieu Objective Glucocorticoid-induced leucine zipper (GILZ) is a glucocorticoid-induced protein, the reported molecular interactions of which suggest that it functions to inhibit inflammation. However, the role of endogenous GILZ in the regulation of inflammation in vivo has not been established. This study was undertaken to examine the expression and function of GILZ in vivo in collagen-induced arthritis (CIA), a murine model of rheumatoid arthritis (RA), and in RA synoviocytes. Methods GILZ expression was detected in mouse and human synovium by immunohistochemistry and in cultured cells by real-time polymerase chain reaction and permeabilization flow cytometry. GILZ function was assessed in vivo by small interfering RNA (siRNA) silencing using cationic liposome,encapsulated GILZ or control nontargeting siRNA and was assessed in vitro using transient overexpression. Results GILZ was readily detectable in the synovium of mice with CIA and was up-regulated by therapeutic doses of glucocorticoids. Depleting GILZ expression in vivo increased the clinical and histologic severity of CIA and increased synovial expression of tumor necrosis factor and interleukin-1 (IL-1), without affecting the levels of circulating cytokines or anticollagen antibodies. GILZ was highly expressed in the synovium of patients with active RA and in cultured RA synovial fibroblasts, and GILZ overexpression in synovial fibroblasts inhibited IL-6 and IL-8 release. Conclusion Our findings indicate that GILZ functions as an endogenous inhibitor of chronic inflammation via effects on cytokine expression and suggest that local modulation of GILZ expression could be a beneficial therapeutic strategy. [source] Plasminogen activator inhibitor 1 gene polymorphisms and mirtazapine responses in Koreans with major depressionASIA-PACIFIC PSYCHIATRY, Issue 3 2009Hun Soo Chang PhD Abstract Introduction: Brain-derived neurotrophic factor (BDNF) is involved in the pathophysiology of mental disorders and in the mechanism of action of antidepressant medications. The mature form of BDNF is derived from proBDNF through tissue type plasminogen activator (tPA) and the plasminogen system in the brain, which is regulated by an endogenous inhibitor, plasminogen activator inhibitor (PAI). Therefore, PAI may be involved in the development of major depressive disorder (MDD) and its response to antidepressant treatment. The present study determined the relationship between the 4G/5G polymorphism in the PAI1 gene and the clinical outcome of mirtazapine treatment in 271 Korean MDD patients. Methods: We tested the association between the polymorphism and response to mirtazapine treatment or percentage decrease of the 21-item Hamilton Depression Rating (HAMD21) scores using multiple logistic and linear regression analysis. Results: PAI1 4G/5G genotypes and allele distributions were comparable between responders and non-responders during the treatment period. Similarly, linear regression showed no association between genotypes or alleles and the percentage decline in total HAMD21 with mirtazapine treatment. In the analysis of symptomatic subscores, the percentage decline in the psychic anxiety and delusion scores after 4 weeks of mirtazapine treatment showed a statistical trend to a difference among genotypes, although it was not statistically significance. Discussion: In this first pharmacogenetics study of the PAI1 4G/5G polymorphism and mirtazapine treatment response, our results do not support the hypothesis that this polymorphism is involved in the therapeutic response to mirtazapine. [source] Endogenous nitric oxide synthase inhibitors in sickle cell disease: abnormal levels and correlations with pulmonary hypertension, desaturation, haemolysis, organ dysfunction and deathBRITISH JOURNAL OF HAEMATOLOGY, Issue 4 2009Gregory J. Kato Summary Pulmonary hypertension (PH) in patients with sickle cell disease (SCD) is linked to intravascular haemolysis, impaired nitric oxide bioavailability, renal dysfunction, and early mortality. Asymmetric dimethylarginine (ADMA), an endogenous inhibitor of nitric oxide synthases (NOS), is associated with vascular disease in other populations. We determined the plasma concentrations for several key arginine metabolites and their relationships to clinical variables in 177 patients with SCD and 29 control subjects: ADMA, symmetric dimethylarginine (SDMA), NG-monomethyl L-arginine (L-NMMA), N-omega-hydroxy-L-arginine (NOHA), arginine and citrulline. The median ADMA was significantly higher in SCD than controls (0·94 ,mol/l vs. 0·31 ,mol/l, P < 0·001). Patients with homozygous SCD had a remarkably lower ratio of arginine to ADMA (50 ,mol/l vs. 237, P < 0·001). ADMA correlated with markers of haemolysis, low oxygen saturation and soluble adhesion molecules. PH was associated with high levels of ADMA and related metabolites. Higher ADMA level was associated with early mortality, remaining significant in a multivariate analysis. Subjects with homozygous SCD have high systemic levels of ADMA, associated with PH and early death, implicating ADMA as a functional NOS inhibitor in these patients. These defects and others converge on the nitric oxide pathway in homozygous SCD with vasculopathy. [source] Resolvin D1 attenuates activation of sensory transient receptor potential channels leading to multiple anti-nociceptionBRITISH JOURNAL OF PHARMACOLOGY, Issue 3 2010S Bang BACKGROUND AND PURPOSE Temperature-sensitive transient receptor potential ion channels (thermoTRPs) expressed in primary sensory neurons and skin keratinocytes play a crucial role as peripheral pain detectors. Many natural and synthetic ligands have been found to act on thermoTRPs, but little is known about endogenous compounds that inhibit these TRPs. Here, we asked whether resolvin D1 (RvD1), a naturally occurring anti-inflammatory and pro-resolving lipid molecule is able to affect the TRP channel activation. EXPERIMENTAL APPROACH We examined the effect of RvD1 on the six thermoTRPs using Ca2+ imaging and whole cell electrophysiology experiments using the HEK cell heterologous expression system, cultured sensory neurons and HaCaT keratinocytes. We also checked changes in agonist-specific acute licking/flicking or flinching behaviours and TRP-related mechanical and thermal pain behaviours using Hargreaves, Randall-Selitto and von Frey assay systems with or without inflammation. KEY RESULTS RvD1 inhibited the activities of TRPA1, TRPV3 and TRPV4 at nanomolar and micromolar levels. Consistent attenuations in agonist-specific acute pain behaviours by immediate peripheral administration with RvD1 were also observed. Furthermore, local pretreatment with RvD1 significantly reversed mechanical and thermal hypersensitivity in inflamed tissues. CONCLUSIONS AND IMPLICATIONS RvD1 was a novel endogenous inhibitor for several sensory TRPs. The results of our behavioural studies suggest that RvD1 has an analgesic potential via these TRP-related mechanisms. [source] Thrombin-induced platelet endostatin release is blocked by a proteinase activated receptor-4 (PAR4) antagonistBRITISH JOURNAL OF PHARMACOLOGY, Issue 4 2001Li Ma Endostatin is a potent endogenous inhibitor of angiogenesis that was recently shown to be stored in platelets and released in response to thrombin, but not ADP. In the present study, we have tested the hypothesis that thrombin-induced endostatin release from rat platelets is mediated via proteinase-activated receptor-4 (PAR4). Immunoprecipitation and Western blotting confirmed that endostatin is contained within rat platelets. Aggregation and release of endostatin could be elicited by thrombin (0.5 , 1.0 U ml,1) or by specific PAR4 agonist (AYPGKF-NH2; AY-NH2; 15 , 50 ,M). Significant release of endostatin could be induced by a dose of thrombin below that necessary for induction of aggregation. An adenosine diphosphate (ADP) scavenger, apyrase, inhibited the platelet aggregation induced by thrombin, but not the release of endostatin. In contrast, a selective PAR4 antagonist (trans-cinnamoyl-YPGKF-NH2; tcY-NH2) prevented endostatin release and aggregation induced by thrombin or by AY-NH2. We conclude that thrombin-induced endostatin release from rat platelets is PAR4-mediated via an ADP-independent mechanism that can occur independently of platelet aggregation. British Journal of Pharmacology (2001) 134, 701,704; doi:10.1038/sj.bjp.0704312 [source] Asymmetric dimethylarginine (ADMA): the silent transition from an ,uraemic toxin' to a global cardiovascular risk moleculeEUROPEAN JOURNAL OF CLINICAL INVESTIGATION, Issue 2 2005D. Fliser Abstract Endothelial dysfunction as a result of reduced bioavailability of nitric oxide (NO) plays a central role in the process of atherosclerotic vascular disease. In endothelial cells NO is synthesized from the amino acid l -arginine by the action of the NO synthase (NOS), which can be blocked by endogenous inhibitors such as asymmetric dimethylarginine (ADMA). Acute systemic administration of ADMA to healthy subjects significantly reduces NO generation, and causes an increase in systemic vascular resistance and blood pressure. Increased plasma ADMA levels as a result of reduced renal excretion have been associated with atherosclerotic complications in patients with terminal renal failure. However, a significant relationship between ADMA and traditional cardiovascular risk factors such as advanced age, high blood pressure and serum LDL-cholesterol, has been documented even in individuals without manifest renal dysfunction. As a consequence, the metabolism of ADMA by the enzyme dimethylarginine dimethylaminohydrolase (DDAH) has come into the focus of cardiovascular research. It has been proposed that dysregulation of DDAH with consecutive increase in plasma ADMA concentration and chronic NOS inhibition is a common pathophysiological pathway in numerous clinical conditions. Thus, ADMA has emerged as a potential mediator of atherosclerotic complications in patients with coronary heart disease, peripheral vascular disease, stroke, etc., being the culprit and not only an innocent biochemical marker of the atherosclerotic disease process. [source] Differential regulation of CaMKII inhibitor , protein expression after exposure to a novel context and during contextual fear memory formationGENES, BRAIN AND BEHAVIOR, Issue 6 2010K. Radwa Understanding of the molecular basis of long-term fear memory (fear LTM) formation provides targets in the treatment of emotional disorders. Ca2+/calmodulin-dependent protein kinase II (CaMKII) is one of the key synaptic molecules involved in fear LTM formation. There are two endogenous inhibitor proteins of CaMKII, CaMKII N, and N,, which can regulate CaMKII activity in vitro. However, the physiological role of these endogenous inhibitors is not known. Here, we have investigated whether CaMKII N, protein expression is regulated after contextual fear conditioning or exposure to a novel context. Using a novel CaMKII N, -specific antibody, CaMKII N, expression was analysed in the naďve mouse brain as well as in the amygdala and hippocampus after conditioning and context exposure. We show that in naďve mouse forebrain CaMKII N, protein is expressed at its highest levels in olfactory bulb, prefrontal and piriform cortices, amygdala and thalamus. The protein is expressed both in dendrites and cell bodies. CaMKII N, expression is rapidly and transiently up-regulated in the hippocampus after context exposure. In the amygdala, its expression is regulated only by contextual fear conditioning and not by exposure to a novel context. In conclusion, we show that CaMKII N, expression is differentially regulated by novelty and contextual fear conditioning, providing further insight into molecular basis of fear LTM. [source] EFFECT OF FROZEN TEMPERATURE AND STORAGE TIME ON CALPAINS, CATHEPSINS (B, B + L, H AND D) AND THEIR ENDOGENOUS INHIBITORS IN GOAT MUSCLESJOURNAL OF FOOD BIOCHEMISTRY, Issue 2 2006N.S. NAGARAJ ABSTRACT The effects of frozen storage on the biochemical properties of myofibrils, muscle proteinases (cathepsins and calpains) and their endogenous inhibitors were investigated. Longissimus dorsi, biceps femoris, semimembranosus and semitendinosus muscles from goat were frozen (,15C) and studied up to 120 days. The results showed that the percentage change in sarcomere length was 8.4,13.1. The calpain activity was determined after separation on a diethylaminoethyl,Sephacel column (Sigma, St. Louis, MO). Significantly greater percentage of calpain II activity was recovered when compared to calpain I. There was a 15,25% loss in calpastatin inhibitory activity, and the cystatin level fell by 11,16% after 80 days. Cathepsin B, B + L, H and D were very stable when compared to calpains. The calcium concentration may also be the factor for calpain activation. The sodium dodecyl sulfate,polyacrylamide gel electrophoresis result showed the appearance of 55 kDa components. It was concluded that calpains, not cathepsins, play an important role in the proteolysis of myofibrillar proteins at the freezing temperature. [source] Endogenous Mechanisms of Inhibition of Platelet FunctionMICROCIRCULATION, Issue 3 2005RICHARD C. JIN MA ABSTRACT Platelets play an important role in coagulation, in maintenance of hemostasis, and in the pathophysiology of thrombotic diseases. In response to blood vessel injury, platelets accumulate at the site, recruit other platelets, promote clotting, and form a hemostatic plug to prevent hemorrhage. By contrast, several inhibitory mechanisms modulate platelet function and act in a synergistic manner to prevent pathologic thrombus formation. This review focuses on the principal endogenous inhibitors of platelet function and the central role of the normal endothelium in these inhibitory processes. The main endothelium-derived platelet inhibitors include nitric oxide, prostacyclin, and Ecto-ADPase/CD39/NTPDase. Each of these factors is discussed in turn, and the specific mechanisms by which they inhibit platelet function are reviewed. [source] Mercury Exposure Increases Circulating Net Matrix Metalloproteinase (MMP)-2 and MMP-9 ActivitiesBASIC AND CLINICAL PHARMACOLOGY & TOXICOLOGY, Issue 4 2009Anna L. B. Jacob-Ferreira We investigated whether there is an association between the circulating levels of MMP-2, MMP-9, their endogenous inhibitors (the tissue inhibitors of metalloproteinases; TIMPs) and the circulating Hg levels in 159 subjects environmentally exposed to Hg. Blood and plasma Hg were determined by inductively coupled plasma-mass spectrometry (ICP-MS). MMP and TIMP concentrations were measured in plasma samples by gelatin zymography and ELISA respectively. Thiobarbituric acid-reactive species (TBARS) were measured in plasma to assess oxidative stress. Selenium (Se) levels were determined by ICP-MS because it is an antioxidant. The relations between bioindicators of Hg and the metalloproteinases levels were examined using multivariate regression models. While we found no relation between blood or plasma Hg and MMP-9, plasma Hg levels were negatively associated with TIMP-1 and TIMP-2 levels, and thereby with increasing MMP-9/TIMP-1 and MMP-2/TIMP-2 ratios, thus indicating a positive association between plasma Hg and circulating net MMP-9 and MMP-2 activities. These findings provide a new insight into the possible biological mechanisms of Hg toxicity, particularly in cardiovascular diseases. [source] Notch: Implications of endogenous inhibitors for therapyBIOESSAYS, Issue 6 2010Ivan Dikic Abstract Soluble components of Notch signalling can be applied to manipulate a central pathway essential for the development of metazoans and often deregulated in illnesses such as stroke, cancer or cardiovascular diseases. Commonly, the Notch cascade is inhibited by small compound inhibitors, which either block the proteolysis of Notch receptors by ,-secretases or interfere with the transcriptional activity of the Notch intracellular domain. Specific antibodies can also be used to inhibit ligand-induced activation of Notch receptors. Alternatively, naturally occurring endogenous inhibitors of Notch signalling might offer a specific way to block receptor activation. Examples are the soluble variants of the canonical Notch ligand Jagged1 and the non-canonical Notch ligand Dlk1, both deprived of their transmembrane regions upon ectodomain shedding, or the bona fide secreted molecule EGFL7. We present frequently used methods to decrease Notch signalling, and we discuss how soluble Notch inhibitors may be used to treat diseases. [source] The effect of Phyllanthus niruri on urinary inhibitors of calcium oxalate crystallization and other factors associated with renal stone formationBJU INTERNATIONAL, Issue 9 2002A.M. Freitas Objective,To evaluate the effect of an aqueous extract of Phyllanthus niruri (Pn), a plant used in folk medicine to treat lithiasis, on the urinary excretion of endogenous inhibitors of lithogenesis, citrate, magnesium and glycosaminoglycans (GAGs). Materials and methods,The effect of chronic (42 days) administration of Pn (1.25 mg/mL/day, orally) was evaluated in a rat model of urolithiasis induced by the introduction of a calcium oxalate (CaOx) seed into the bladder of adult male Wistar rats. The animals were divided into four groups: a sham control (16 rats); a control+Pn (six); CaOx+water instead of Pn (14); and CaOx+Pn (22). Plasma and urine were collected after 42 days of treatment for biochemical analysis and the determination of urinary excretion of citrate, magnesium and GAGs. The animals were then killed and the calculi analysed. Results,The creatinine clearance or urinary and plasma concentrations of Na+, K+, Ca2+, oxalate, phosphate and uric acid were unaffected by Pn or the induction of lithiasis. Treatment with Pn strongly inhibited the growth of the matrix calculus and reduced the number of stone satellites compared with the group receiving water. The calculi were eliminated or dissolved in some treated animals (three of 22). The urinary excretion of citrate and magnesium was unaffected by Pn treatment. However, the mean (sd) urinary concentration of GAGs was significantly lower in rats treated with CaOx+Pn, at 5.64 (0.86) mg/g creatinine, than when treated with CaOx + water, at 11.78 (2.21) mg/g creatinine. In contrast, the content of GAGs in the calculi was higher in the CaOx + Pn rats, at 48.0 (10.4) g/g calculus, than in the CaOx + water group, at 16.6 (9.6) g/g calculus. Conclusion,These results show that Pn has an inhibitory effect on crystal growth, which is independent of changes in the urinary excretion of citrate and Mg, but might be related to the higher incorporation of GAGs into the calculi. [source] Therapeutic manipulation of glucocorticoid metabolism in cardiovascular diseaseBRITISH JOURNAL OF PHARMACOLOGY, Issue 5 2009Patrick W.F. Hadoke The therapeutic potential for manipulation of glucocorticoid metabolism in cardiovascular disease was revolutionized by the recognition that access of glucocorticoids to their receptors is regulated in a tissue-specific manner by the isozymes of 11,-hydroxysteroid dehydrogenase. Selective inhibitors of 11,-hydroxysteroid dehydrogenase type 1 have been shown recently to ameliorate cardiovascular risk factors and inhibit the development of atherosclerosis. This article addresses the possibility that inhibition of 11,-hydroxsteroid dehydrogenase type 1 activity in cells of the cardiovascular system contributes to this beneficial action. The link between glucocorticoids and cardiovascular disease is complex as glucocorticoid excess is linked with increased cardiovascular events but glucocorticoid administration can reduce atherogenesis and restenosis in animal models. There is considerable evidence that glucocorticoids can interact directly with cells of the cardiovascular system to alter their function and structure and the inflammatory response to injury. These actions may be regulated by glucocorticoid and/or mineralocorticoid receptors but are also dependent on the 11,-hydroxysteroid dehydrogenases which may be expressed in cardiac, vascular (endothelial, smooth muscle) and inflammatory (macrophages, neutrophils) cells. The activity of 11,-hydroxysteroid dehydrogenases in these cells is dependent upon differentiation state, the action of pro-inflammaotory cytokines and the influence of endogenous inhibitors (oxysterols, bile acids). Further investigations are required to clarify the link between glucocorticoid excess and cardiovascular events and to determine the mechanism through which glucocorticoid treatment inhibits atherosclerosis/restenosis. This will provide greater insights into the potential benefit of selective 11,-hydroxysteroid dehydrogenase inhibitors in treatment of cardiovascular disease. [source] Functional and Edible Uses of Soy Protein ProductsCOMPREHENSIVE REVIEWS IN FOOD SCIENCE AND FOOD SAFETY, Issue 1 2008Preeti Singh ABSTRACT:, Consumers are becoming increasingly interested in healthful foods and are open to soy protein ingredients. Soybeans as food are very versatile and a rich source of essential nutrients. They are also an excellent source of good-quality protein, comparable to other protein foods, and suitable for all ages. Adverse nutritional and other undesirable effects followed by the consumption of raw soybean meal have been attributed to the presence of endogenous inhibitors of digestive enzymes and lectins, as well as poor digestibility. To improve the nutritional quality of soy foods, inhibitors and lectins are generally inactivated by heat or eliminated by fractionation during food processing. Soybeans provide an alternative source of protein for people who are allergic to milk protein. Soy protein is highly digestible (92% to 100%) and contains all essential amino acids. Although relatively low in methionine, it is a good source of lysine. Soy-protein products contain a high concentration of isoflavones, up to 1 g/kg. Increased acceptance of soy proteins is due to unmatched qualities like good functional properties in food applications, high nutritional quality, abundance, availability, and low cost. At present the various forms of soy proteins are primarily utilized for their functional effects rather than their nutritional properties. This article summarizes the integrated overview of the widely available, scattered information about the nutritional and functional uses of the soy proteins when applied in food systems and intends to present the most current knowledge with an interest to stimulate further research to optimize their beneficial effects. [source] | ||||||||||||||||