scholarly journals Activation of human complement serine-proteinase C1r is down-regulated by a Ca2+-dependent intramolecular control that is released in the C1 complex through a signal transmitted by C1q

1994 ◽  
Vol 301 (2) ◽  
pp. 509-516 ◽  
Author(s):  
N M Thielens ◽  
C Illy ◽  
I M Bally ◽  
G J Arlaud
Keyword(s):  
Serine Proteinase ◽  
Intrinsic Property ◽  
Inhibitory Effect ◽  
Activation Process ◽  
Activation Kinetics ◽  
Activation Reaction ◽  
Comparable Effect ◽  
Partial Release ◽  
Intramolecular Mechanism

The activation of human C1, a Ca(2+)-dependent complex proteinase comprising a non-enzymic protein, C1q, and two serine proteinases, C1r and C1s, is based primarily on the intrinsic property of C1r to autoactivate. The aim of the present study was to investigate the mechanisms involved in the regulation of C1r autoactivation, with particular attention to the role of Ca2+ ions. Spontaneous activation of proenzyme C1r was observed upon incubation in the presence of EDTA, whereas Ca2+ ions reduced markedly the activation process. Several lines of evidence indicated that Ca2+ inhibited the intramolecular activation reaction but had little or no effect on the intermolecular activation reaction. C1q caused partial release of this inhibitory effect of Ca2+. Complete stabilization of C1r in its proenzyme form was obtained upon incorporation within the Ca(2+)-dependent C1s-C1r-C1r-C1s tetramer, and a comparable effect was observed when C1s was replaced by its Ca(2+)-binding alpha-fragment. Both tetramers, C1s-C1r-C1r-C1s and C1s alpha-C1r-C1r-C1s alpha, readily associated with C1q to form 16.0 S and 14.7 S complexes respectively in which C1r fully recovered its activation potential. Both complexes showed indistinguishable activation kinetics, indicating that the gamma B catalytic region of C1s plays no role in the mechanism that triggers C1r activation in C1. The collagen-like fragments of C1q retained the ability to bind to C1s-C1r-C1r-C1s, but, in contrast with intact C1q, failed to induce C1r activation in the resulting complex at temperatures above 25 degrees C. On the basis of these observations it is proposed that activation of the serine-proteinase domain of C1r is controlled by a Ca(2+)-dependent intramolecular mechanism involving the Ca(2+)-binding alpha-region, and that this control is released in C1 by a signal originating in C1q and transmitted through the C1q/C1r interface.

scholarly journals Bio-Insecticide of Thymus vulgaris and Ocimum basilicum Extract from Cell Suspensions and Their Inhibitory Effect against Serine, Cysteine, and Metalloproteinases of the Red Palm Weevil (Rhynchophorus ferrugineus)

Insects ◽  
2021 ◽  
Vol 12 (5) ◽  
pp. 405
Author(s):  
Hossam Moustafa Darrag ◽  
Mohammed Refdan Alhajhoj ◽  
Hany Ezzat Khalil
Keyword(s):  
Cell Suspension ◽  
Serine Proteinase ◽  
Inhibitory Effect ◽  
Cell Suspensions ◽  
Thymus Vulgaris ◽  
Red Palm Weevil ◽  
Phenolic Constituents ◽  
Germacrene D ◽  
Ic50 Values

The current study was designed to investigate the insecticide role of volatile constituents produced from cell suspensions of T. vulgaris and O. basilicum against R. ferrugineus. Constituents were extracted from cell suspension after 40 days. Growth kinetics were measured with an inoculation of Verticillium dahliae and identified by GC-MS. Total volatile phenolic constituents were measured. Insecticidal activity against R. ferrugineus (adult) and proteolytic enzyme activity in larvae were assessed. GC-MS showed that the T. vulgaris extract has higher amounts of thymol, p-cymene, γ-terpinene, β-caryophyllene, and linalool in comparison to the O. basilicum extract, which is rich in estragole, β-terpineol, (E)-β-ocimene, 1,8-cineole, germacrene D, and eugenol. The T. vulgaris extract showed an LC50 of 1032 µg/mL, followed by O. basilicum with an LC50 of 1246 µg/mL. The IC50 values against the total proteases were 110.8 and 119.4 µg/mL for T. vulgaris and O. basilicum, respectively. The IC50 for the trypsin-like serine proteinase assessment was 81.6 and 91 µg/mL for T. vulgaris and O. basilicum, respectively. Cysteine, chymotrypsin, and metalloproteinase assessment showed an IC50 above 5000 µg/mL for both extracts. The study is proposed as a potential approach to use T. vulgaris and O. basilicum extract as a bio-insecticide against R. ferrugineus using an accessible and efficient cell suspension technique.

scholarly journals Functional role of the polysaccharide component of rabbit thrombomodulin proteoglycan. Effects on inactivation of thrombin by antithrombin, cleavage of fibrinogen by thrombin and thrombin-catalysed activation of factor V

1990 ◽  
Vol 270 (2) ◽  
pp. 419-425 ◽  
Author(s):  
M C Bourin ◽  
U Lindahl
Keyword(s):  
Protein C ◽  
Inhibitory Effect ◽  
Factor V ◽  
Promoting Effect ◽  
Activation Kinetics ◽  
Polysaccharide Chain ◽  
Factor Va ◽  
Kinetics Of ◽  
Similar Sample

Thrombomodulin (TM), a major anticoagulant protein at the vessel wall, serves as a potent cofactor for the activation of Protein C by thrombin. Previous work has indicated that (rabbit) TM is a proteoglycan that contains a single polysaccharide chain, tentatively identified as a sulphated galactosaminoglycan, and furthermore suggested that this component may be functionally related to additional anticoagulant activities expressed by the TM molecule [Bourin, Ohlin, Lane, Stenflo & Lindahl (1988) J. Biol. Chem. 263, 8044-8052]. Results of the present study establish that (enzymic) removal of the polysaccharide chain abolishes the inhibitory effect of TM on thrombin-induced fibrinogen clotting as well as the promoting effect of TM on the inactivation of thrombin by antithrombin, but does not affect the ability of TM to serve as a cofactor in the activation of Protein C. Studies of yet another biological activity of rabbit TM, namely the ability to prevent the activation of Factor V by thrombin [Esmon, Esmon & Harris (1982) J. Biol. Chem. 257, 7944-7947], confirmed that TM markedly delays the conversion of the native 330 kDa Factor V precursor into polypeptide intermediates, and further into the 96 kDa heavy chain and 71-74 kDa light-chain components of activated Factor Va. In contrast, the activation kinetics of a similar sample of Factor V incubated with thrombin in the presence of chondroitinase ABC-digested TM did not differ from that observed in the absence of TM. It is concluded that the inhibitory effect of TM on Factor V activation also depends on the presence of the polysaccharide component on the TM molecule.

Effect of Dipyridamole on Spontaneous Platelet Aggregation in Whole Blood Decreases with the Time After Venepuncture: Evidence for the Role of ADP

1987 ◽  
Vol 58 (02) ◽  
pp. 744-748 ◽  
Author(s):  
A R Saniabadi ◽  
G D O Lowe ◽  
J C Barbenel ◽  
C D Forbes
Keyword(s):  
Platelet Aggregation ◽  
Correlation Coefficient ◽  
Whole Blood ◽  
Blood Platelet ◽  
Inhibitory Effect ◽  
Time Interval ◽  
Adp Receptor ◽  
Spontaneous Platelet Aggregation

SummarySpontaneous platelet aggregation (SPA) was studied in human whole blood at 3, 5, 10, 20, 30, 40 and 60 minutes after venepuncture. Using a whole blood platelet counter, SPA was quantified by measuring the fall in single platelet count upon rollermixing aliquots of citrated blood at 37° C. The extent of SPA increased with the time after venepuncture, with a correlation coefficient of 0.819. The inhibitory effect of dipyridamole (Dipy) on SPA was studied: (a) 10 μM at each time interval; (b) 0.5-100 μM at 3 and 30 minutes and (c) 15 μM in combination with 100 μM adenosine, 8 μM 2-chloroadenosine (2ClAd, an ADP receptor blocker) and 50 μM aspirin. There was a rapid decrease in the inhibitory effect of Dipy with the time after venepuncture; the correlation coefficient was -0.533. At all the concentrations studied, Dipy was more effective at 3 minutes than at 30 minutes after venepuncture. A combination of Dipy with adenosine, 2ClAd or aspirin was a more effective inhibitor of SPA than either drug alone. However, when 15 μM Dipy and 10 μM Ad were added together, the inhibitory effect of Dipy was not increased significantly, suggesting that Dipy inhibits platelet aggregation independent of Ad. The increase in SPA with the time after venepuncture was abolished when blood was taken directly into the anticoagulant containing 5 μM 2ClAd. It is suggested that ADP released from the red blood cells is responsible for the increased platelet aggregability with the time after venepuncture and makes a serious contribution to the artifacts of in vitro platelet function studies.

Effect of human galanin on the response of circulating catecholamines to hypoglycemia in man

1995 ◽  
Vol 133 (6) ◽  
pp. 723-728 ◽  
Author(s):  
Ettore C degli Uberti ◽  
Maria R Ambrosio ◽  
Marta Bondanelli ◽  
Giorgio Transforini ◽  
Alberto Valentini ◽  
...  
Keyword(s):  
Heart Rate ◽  
Healthy Subjects ◽  
Sympathetic Nerve Activity ◽  
Heart Rate Response ◽  
Statistical Significance ◽  
Inhibitory Effect ◽  
Amino Acid Residues ◽  
Nerve Activity ◽  
Receptor Stimulation

degli Uberti EC, Ambrosio MR, Bondanelli M, Trasforini G, Valentini A, Rossi R, Margutti A, Campo M. Effect of human galanin on the response of circulating catecholamines to hypoglycemia in man. Eur J Endocrinol 1995;133:723–8. ISSN 0804–4643 Human galanin (hGAL) is a neuropeptide with 30 amino acid residues that has been found in the peripheral and central nervous system, where it often co-exists with catecholamines. In order to clarify the possible role of hGAL in the regulation of sympathoadrenomedullary function, the effect of a 60 min infusion of hGAL (80 pmol·kg−1 · min−1) on plasma epinephrine and norepinephrine responses to insulin-induced hypoglycemia in nine healthy subjects was investigated. Human GAL administration significantly reduced both the release of basal norepinephrine and the response to insulin-induced hypoglycemia, whereas it attenuated the epinephrine response by 26%, with the hGAL-induced decrease in epinephrine release failing to achieve statistical significance. Human GAL significantly increased the heart rate in resting conditions and clearly exaggerated the heart rate response to insulin-induced hypoglycemia, whereas it had no effect on the blood pressure. We conclude that GAL receptor stimulation exerts an inhibitory effect on basal and insulin-induced hypoglycemia-stimulated release of norepinephrine. These findings provide further evidence that GAL may modulate sympathetic nerve activity in man but that it does not play an important role in the regulation of adrenal medullary function. Ettore C degli Uberti, Chair of Endocrinology, University of Ferrara, Via Savonarola 9, I-44100 Ferrara, Italy

Biological role of AKT, and regulation of AKT signaling pathway by thymoquinone: perspectives in cancer therapeutics

2020 ◽  
Vol 20 ◽  
Author(s):  
Md. Junaid ◽  
Yeasmin Akter ◽  
Syeda Samira Afrose ◽  
Mousumi Tania ◽  
Md. Asaduzzaman Khan
Keyword(s):  
Clinical Trials ◽  
Signaling Pathways ◽  
Signaling Pathway ◽  
Inhibitory Effect ◽  
Akt Signaling ◽  
Review Article ◽  
Therapeutic Drug ◽  
Akt Signaling Pathway ◽  
Anti Cancer

Background: AKT/PKB is an important enzyme with numerous biological functions, and its overexpression is related to the carcinogenesis. AKT stimulates different signaling pathways that are downstream of activated tyrosine kinases and phosphatidylinositol 3-kinase, hence functions as an important target for anti-cancer drugs. Objective: In this review article, we have interpreted the role of AKT signaling pathways in cancer and natural inhibitory effect of Thymoquinone (TQ) in AKT and its possible mechanism. Method: We have collected the updated information and data on AKT, their role in cancer and inhibitory effect of TQ in AKT signaling pathway from google scholar, PubMed, Web of Science, Elsevier, Scopus and many more. Results: There are many drugs already developed, which can target AKT, but very few among them have passed clinical trials. TQ is a natural compound, mainly found in black cumin, which has been found to have potential anti-cancer activities. TQ targets numerous signaling pathways, including AKT, in different cancers. In fact, many studies revealed that AKT is one of the major targets of TQ. The preclinical success of TQ suggests its clinical studies on cancer. Conclusion: This review article summarizes the role of AKT in carcinogenesis, its potent inhibitors in clinical trials, and how TQ acts as an inhibitor of AKT and TQ’s future as a cancer therapeutic drug.

The Immunomodulatory Role of G2013 (α-L-Guluronic Acid) on the Expression of TLR2 and TLR4 in HT29 cell line

2019 ◽  
Vol 16 (1) ◽  
pp. 91-95 ◽  
Author(s):  
Hamid Farhang ◽  
Laleh Sharifi ◽  
Mohammad Mehdi Soltan Dallal ◽  
Mona Moshiri ◽  
Zahra Norouzbabaie ◽  
...  
Keyword(s):  
Inflammatory Responses ◽  
Inflammatory Diseases ◽  
Rna Extraction ◽  
Cell Plate ◽  
Inhibitory Effect ◽  
Control Group ◽  
Ht29 Cells ◽  
Guluronic Acid ◽  
Tlr4 Mrna

Background: The non-steroidal anti-inflammatory drugs (NSAIDs) play crucial role in the controlling of inflammatory diseases. Due to the vast side effects of NSAIDs, its use is limited. G2013 or &amp;#945;-L-Guluronic Acid is a new NSAID with immunomodulatory features. Objectives: Considering the leading role of TLRs in inflammatory responses, in this study, we aimed to evaluate G2013 cytotoxicity and its effect on the expression of TLR2 and TLR4 molecules. Methods: HEK293-TLR2 and HEK293-TLR4 cells were cultured and seeded on 96-well cell plate, and MTT assay was performed for detecting the viability of the cells after treatment with different concentrations of G2013. HT29 cells were grown and treated with low and high doses of G2013. After total RNA extraction and cDNA synthesis, quantitative real-time PCR were performed to assess the TLR2 and TLR4 mRNA synthesis. Results: We found that concentrations of ≤125 &amp;#181;g/ml of G2013 had no apparent cytotoxicity effect on the HEK293-TLR2 and -TLR4 cells. Our results indicated that after G2013 treatment (5 &amp;#181;g/ml) in HT29 cells, TLR2 and TLR4 mRNA expression decreased significantly compared with the untreated control group (p=0.02 and p=0.001 respectively). Conclusion: The results of this study revealed that G2013 can down regulate the TLR2 and TLR4 gene expression and exerts its inhibitory effect. Our findings are parallel to our previous finding which showed G2013 ability to down regulate the signaling pathway of TLRs. However, further studies are needed to identify the molecular mechanism of G2013.<p&gt;

scholarly journals Who’s Afraid of Adversariality? Conflict and Cooperation in Argumentation

Topoi ◽  
2020 ◽  
Author(s):  
Catarina Dutilh Novaes
Keyword(s):  
Conflict Management ◽  
Recent Literature ◽  
Intrinsic Property ◽  
Prima Facie ◽  
Consensus Building ◽  
Conflict And Cooperation ◽  
Contextual Features

AbstractSince at least the 1980s, the role of adversariality in argumentation has been extensively discussed within different domains. Prima facie, there seem to be two extreme positions on this issue: argumentation should (ideally at least) never be adversarial, as we should always aim for cooperative argumentative engagement; argumentation should be and in fact is always adversarial, given that adversariality (when suitably conceptualized) is an intrinsic property of argumentation. I here defend the view that specific instances of argumentation are (and should be) adversarial or cooperative to different degrees. What determines whether an argumentative situation should be primarily adversarial or primarily cooperative are contextual features and background conditions external to the argumentative situation itself, in particular the extent to which the parties involved have prior conflicting or else convergent interests. To further develop this claim, I consider three teloi that are frequently associated with argumentation: the epistemic telos, the consensus-building telos, and the conflict management telos. I start with a brief discussion of the concepts of adversariality, cooperation, and conflict in general. I then sketch the main lines of the debates in the recent literature on adversariality in argumentation. Next, I discuss the three teloi of argumentation listed above in turn, emphasizing the roles of adversariality and cooperation for each of them.

scholarly journals Albizia chinensis bark extract ameliorates the genotoxic effect of cyclophosphamide

2020 ◽  
Vol 44 (1) ◽  
Author(s):  
Marian Nabil ◽  
Entesar E. Hassan ◽  
Neven S. Ghaly ◽  
Fawzia A. Aly ◽  
Farouk R. Melek ◽  
...  
Keyword(s):  
Folk Medicine ◽  
Inhibitory Effect ◽  
Protective Role ◽  
Bark Extract ◽  
Repeated Treatment ◽  
Mouse Bone Marrow ◽  
Sperm Abnormalities ◽  
Wide Range ◽  
Different Doses

Abstract Background The genus Albizia (Leguminoseae) is used in folk medicine for the treatment of a wide range of ailments. Recently, saponins from plant origin have attracted much attention. Saponins are recorded to have a broad range of biological and pharmacological activities. This study was performed to evaluate the protective role of Albizia chinensis bark methanolic extract (MEAC) against the genotoxicity induced by cyclophosphamide (CP) using different mutagenic parameters. Results The results showed that MEAC induced an inhibitory effect against chromosomal aberrations of CP in mouse bone marrow and spermatocytes. Such effect was found to be significant (p < 0.01) with a dose of 100 mg/kg treated once for 24 h and also after repeated treatment at a dose of 25 mg/kg for 7 days. In sperm abnormalities, the protective effect of Albizia extract showed a dose-related relationship. Different doses of MEAC (25, 50, and 100 mg/kg) significantly (p < 0.01) ameliorated sperm abnormalities induced by CP dose-dependently. The percentage of sperm abnormalities was decreased to 5.14 ± 0.72 in the group of animals treated with CP plus MEAC (100 mg/kg) indicating an inhibitory effect of about 50%. Conclusion MEAC at the doses examined was non-genotoxic compared to control (negative) and exhibited a protective role against CP genotoxicity.

POSSIBLE ROLE OF 5α-ANDROSTANE-3α,17β-DIOL IN THE CONTROL OF FOLLICLE-STIMULATING HORMONE SECRETION IN THE IMMATURE FEMALE RAT

1982 ◽  
Vol 92 (1) ◽  
pp. 37-42 ◽  
Author(s):  
H. M. A. MEIJS-ROELOFS ◽  
P. KRAMER ◽  
L. GRIBLING-HEGGE
Keyword(s):  
Inhibitory Action ◽  
Combined Treatment ◽  
Hormone Secretion ◽  
Inhibitory Effect ◽  
Ovariectomized Rats ◽  
Female Rat ◽  
Immature Rat ◽  
Rat Strain ◽  
Intact Rats

A possible role of 5α-androstane-3α,17β-diol (3α-androstanediol) in the control of FSH secretion was studied at various ages in ovariectomized rats. In the rat strain used, vaginal opening, coincident with first ovulation, generally occurs between 37 and 42 days of age. If 3α-androstanediol alone was given as an ovarian substitute, an inhibitory effect on FSH release was evident with all three doses tested (50, 100, 300 μg/100 g body wt) between 13 and 30 days of age; at 33–35 days of age only the 300 μg dose caused some inhibition of FSH release. Results were more complex if 3α-androstanediol was given in combined treatment with oestradiol and progesterone. Given with progesterone, 3α-androstanediol showed a synergistic inhibitory action on FSH release between 20 and 30 days of age. However, when 3α-androstanediol was combined with oestradiol a clear decrease in effect, as compared to the effect of oestradiol alone, was found between 20 and 30 days of age. Also the effect of combined oestradiol and progesterone treatment was greater than the effect of combined treatment with oestradiol, progesterone and 3α-androstanediol. At all ages after day 20 none of the steroid combinations tested was capable of maintaining FSH levels in ovariectomized rats similar to those in intact rats. It is concluded that 3α-androstanediol might play a role in the control of FSH secretion in the immature rat, but after day 20 the potentially inhibitory action of 3α-androstanediol on FSH secretion is limited in the presence of oestradiol.

scholarly journals F4/80+ Kupffer Cell-Derived Oncostatin M Sustains the Progression Phase of Liver Regeneration through Inhibition of TGF-β2 Pathway

Molecules ◽  
2021 ◽  
Vol 26 (8) ◽  
pp. 2231
Author(s):  
Qingjun Lu ◽  
Hao Shen ◽  
Han Yu ◽  
Jing Fu ◽  
Hui Dong ◽  
...  
Keyword(s):  
Liver Regeneration ◽  
Serum Levels ◽  
Inhibitory Effect ◽  
Regenerative Process ◽  
Oncostatin M ◽  
Hepatocyte Proliferation ◽  
Initiation Phase ◽  
Distinct Role

The role of Kupffer cells (KCs) in liver regeneration is complicated and controversial. To investigate the distinct role of F4/80+ KCs at the different stages of the regeneration process, two-thirds partial hepatectomy (PHx) was performed in mice to induce physiological liver regeneration. In pre- or post-PHx, the clearance of KCs by intraperitoneal injection of the anti-F4/80 antibody (α-F4/80) was performed to study the distinct role of F4/80+ KCs during the regenerative process. In RNA sequencing of isolated F4/80+ KCs, the initiation phase was compared with the progression phase. Immunohistochemistry and immunofluorescence staining of Ki67, HNF-4α, CD-31, and F4/80 and Western blot of the TGF-β2 pathway were performed. Depletion of F4/80+ KCs in pre-PHx delayed the peak of hepatocyte proliferation from 48 h to 120 h, whereas depletion in post-PHx unexpectedly led to persistent inhibition of hepatocyte proliferation, indicating the distinct role of F4/80+ KCs in the initiation and progression phases of liver regeneration. F4/80+ KC depletion in post-PHx could significantly increase TGF-β2 serum levels, while TGF-βRI partially rescued the impaired proliferation of hepatocytes. Additionally, F4/80+ KC depletion in post-PHx significantly lowered the expression of oncostatin M (OSM), a key downstream mediator of interleukin-6, which is required for hepatocyte proliferation during liver regeneration. In vivo, recombinant OSM (r-OSM) treatment alleviated the inhibitory effect of α-F4/80 on the regenerative progression. Collectively, F4/80+ KCs release OSM to inhibit TGF-β2 activation, sustaining hepatocyte proliferation by releasing a proliferative brake.

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