Plasminogen binding and activation at the surface of Helicobacter pylori CCUG 17874

Identification of interaction partners of outer inflammatory protein A: Computational and experimental insights into how Helicobacter pylori infects host cells

Outer membrane proteins (OMPs) play a key role in facilitating the survival of Helicobacter pylori within the gastric tissue by mediating adherence. Among these proteins, Outer inflammatory protein A (OipA) is a critical factor in H. pylori colonization of the host gastric epithelial cell surface. While the role of OipA in H. pylori attachment and its association with clinical outcomes have been established, the structural mechanisms underlying OipA's action in adherence to gastric epithelial cells remain limited. Our study employed experimental and computational approaches to investigate the interaction partners of OipA on the gastric epithelial cell surface. Initially, we conducted a proteomic analysis using a pull-down assay with recombinant OipA and gastric epithelial cell membrane proteins to identify the OipA interactome. This analysis revealed 704 unique proteins that interacted with OipA. We subsequently analyzed 16 of these OipA partners using molecular modeling tools. Among these 16 partners, we highlight three human proteins, namely Hepatocyte growth factor (HGF), Mesenchymal epithelial transition factor receptor (Met), and Adhesion G Protein-Coupled Receptor B1 (AGRB1) that could play a role in H. pylori adherence to the gastric epithelial cell surface with OipA. Collectively, these findings reveal novel host interactions mediated by OipA, suggesting their potential as therapeutic targets for combating H. pylori infection.

Helicobacter pylori and Pro-Inflammatory Protein Biomarkers in Myocardial Infarction with and without Obstructive Coronary Artery Disease

Myocardial infarction (MI) with obstructive coronary artery disease (MI-CAD) and MI in the absence of obstructive coronary artery disease (MINOCA) affect different populations and may have separate pathophysiological mechanisms, with greater inflammatory activity in MINOCA compared to MI-CAD. Helicobacter pylori (Hp) can cause systemic inflammation and has been associated with cardiovascular disease (CVD). We aimed to investigate whether Hp infection is associated with concentrations of protein biomarkers of inflammation and CVD. In a case-control study, patients with MINOCA (n = 99) in Sweden were included, complemented by matched subjects with MI-CAD (n = 99) and controls (n = 100). Protein biomarkers were measured with a proximity extension assay in plasma samples collected 3 months after MI. The seroprevalence of Hp and cytotoxin-associated gene A (CagA) was determined using ELISA. The associations between protein levels and Hp status were studied with linear regression. The prevalence of Hp was 20.2%, 19.2%, and 16.0% for MINOCA, MI-CAD, and controls, respectively (p = 0.73). Seven proteins were associated with Hp in an adjusted model: tissue plasminogen activator (tPA), interleukin-6 (IL-6), myeloperoxidase (MPO), TNF-related activation-induced cytokine (TRANCE), pappalysin-1 (PAPPA), soluble urokinase plasminogen activator receptor (suPAR), and P-selectin glycoprotein ligand 1 (PSGL-1). Hp infection was present in one in five patients with MI, irrespective of the presence of obstructive CAD. Inflammatory proteins were elevated in Hp-positive subjects, thus not ruling out that Hp may promote an inflammatory response and potentially contribute to the development of CVD.

Therapeutic potentials of Adenostemma lavenia (L.) O.Kuntze evidenced into an array of pharmacological effects and ligand-receptor interactions

This study constructed the phytochemical profiles of Adenostemma lavenia (L) methanol extract (MEAL) and investigated its anti-nociceptive, anti-diarrheal, antipyretic, thrombolytic and anthelmintic effects. The GC-MS characterized MEAL had undergone an in vivo antipyretic effect assayed on Swiss albino mice adopting the yeast-induced pyrexia model, antinociceptive activity tested following acetic acid-induced writhing and formalin-induced licking paw models, anti-diarrheal effect in castor oil-induced diarrhea, castor oil-induced enteropooling, and charcoal-induced intestinal transit tests, in vitro thrombolytic effect using clot-lysis model and anthelmintic effects assayed on Tubifex tubifex nematode. The MEAL biometabolites and associated proteins of target diseases were interacted with computational analysis. The MEAL showed a significant dose-dependent percentage of inhibition in acetic acid-induced writhing and formalin-induced paw licking displaying inhibition of 80.40% in acetic acid-induced writhing and 36.23% and 58.21% in the second phase of the formalin-induced model. The MEAL inhibition of 34.37%, 35.29%, and 42.95% in castor oil-induced diarrhea, castor oil-induced enteropooling, and charcoal-induced gastrointestinal motility, respectively. The MEAL significantly reduced yeast-induced pyrexia. Its biometabolites showed remarkable (-4.1 kcal/mol to 7.4 kcal/mol) binding affinity with the protein receptors. Caryophyllene and Cyclobarbital yielded the best binding scores in this research. Results suggest that pure compounds-based pharmacological investigations are necessary to affirm the therapeutic effects.

Biological Functions of Dillenia pentagyna Roxb. Against Pain, Inflammation, Fever, Diarrhea, and Thrombosis: Evidenced From in vitro, in vivo, and Molecular Docking Study

Dillenia pentagyna Roxb. is traditionally used to treat cancer, wound healing, diabetes, and diarrhea in local tribes. This study was designed to evaluate the pharmacological potentiality of this plant. In vivo analgesic, anti-inflammatory, and antipyretic studies of the methanol extracts of D. pentagyna (MEDP) leaves were performed by using acetic acid-induced nociception, formalin-induced paw licking, and yeast-induced pyrexia assay methods, respectively. In vivo antidiarrheal activity was carried out in mice by following castor oil-induced diarrhea and gastrointestinal transit manner. In vitro thrombolytic experiment was performed employing the clot lysis activity. Besides, a molecular docking study was performed by executing the software (PyRx, Discovery Studio, and UCSF Chimera). In the acetic acid-induced writhing study, MEDP possesses significant writhing inhibition in a dose-dependent manner. It showed 50.86% of maximum inhibition of pain in the case of MEDP at a dose of 400 mg/kg body weight. In the anti-inflammatory study, maximum inhibition rate was observed at a value of 59.98 and 41.29% in early and late phases, respectively, at the dose of 400 mg/kg body weight. In the case of yeast-induced hyperpyrexia, MEDP reduced hyperpyrexia in a dose-dependent manner. In the antidiarrheal assay, MEDP moderately inhibited the occurrence of diarrhea in all the experiments. In the thrombolytic study, a moderate (17.76%) clot lysis potency has been yielded by MEDP. Again, the molecular docking simulation revealed strong binding affinities with almost all the targeted proteins. The present study suggests that the MEDP possesses remarkable pharmacological activity and this finding validated the ethnobotanical significance of D. pentagyna as the source of pain, fever, and diarrhea management agent.

Chemical profiles and pharmacological insights of Anisomeles indica Kuntze: An experimental chemico-biological interaction

Anisomeles indica (L.) Kuntze is an ethnomedicinally important plant that has long been used in traditional medicine to treat a variety of ailments, including dyspepsia, abdominal pain, colic, allergies, inflammation, and rheumatic arthritis. However, the scientific framework underlying these medicinal properties is not well known. This study aimed to investigate the antidepressive, antidiarrheal, thrombolytic, and anti-inflammatory potential of a methanol extract of A. indica (MeOH-AI). The potential bioactive compounds in the MeOH-AI were identified using gas chromatography-mass spectrometry (GC-MS), and antidepressant activities were evaluated using the tail suspension test (TST) and forced swim test (FST). Antidiarrheal effects were also assayed in castor oil-induced diarrhea and gastrointestinal motility studies. The anti-inflammatory activities were explored by examining the effects on protein inhibition and denaturation in heat- and hypotonic solution-induced hemolysis assays. The thrombolytic activity was evaluated using the clot lysis test in human blood. BIOVIA and Schrödinger Maestro (v11.1) were applied for docking analysis to determine binding interactions, and the absorption, distribution, metabolisms, excretion/toxicity (ADME/T) properties of bioactive compounds were explored using a web-based method. The GC-MS analysis of MeOH-AI revealed the presence of several bioactive compounds. MeOH-AI administration resulted in significant (p < 0.01) reductions in the immobility times for both the FST and TST compared with those in the control group. MeOH-AI also induced significant (p < 0.01) reductions in castor oil-induced diarrhea severity and gastrointestinal motility in a mouse model. In addition, the in vitro anti-inflammatory and thrombolytic activity studies produced remarkable responses. The binding assay showed that 4-dehydroxy-N-(4,5-methylenedioxy-2-nitrobenzylidene) tyramine interacts favorably with monoamine oxidase and serotonin and M3 muscarinic acetylcholine receptors, displaying good pharmacokinetic properties, which may mediate the effects of MeOH-AI on depression and diarrhea. Overall, the research findings indicated that MeOH-AI has significant antidepressant, antidiarrheal, and anti-inflammatory effects and may represent an alternative source of novel therapeutic factors.

Chemical, biological and protein-receptor binding profiling of Bauhinia scandens L. stems provide new insights into the management of pain, inflammation, pyrexia and thrombosis

Bauhinia scandens L. (Family, Fabaceae) is a medicinal plant used for conventional and societal medication in Ayurveda. The present study has been conducted to screen the chemical, pharmacological and biochemical potentiality of the methanol extracts of B. scandens stems (MEBS) along with its related fractions including carbon tetrachloride (CTBS), di-chloromethane (DMBS) and n-butanol (BTBS). UPLC-QTOF-MS has been implemented to analyze the chemical compounds of the methanol extracts of Bauhinia scandens stems. Additionally, antinociceptive and anti-inflammatory effects were performed by following the acetic acid-induced writhing test and formalin-mediated paw licking test in the mice model. The antipyretic investigation was performed by Brewer Yeast induced pyrexia method. The clot lysis method was implemented to screen the thrombolytic activity in human serum. Besides, the in silico study was performed for the five selected chemical compounds of Bauhinia scandens, found by UPLC-QTOF-MS By using Discover Studio 2020, UCSF Chimera, PyRx autodock vina and online tools. The MEBS and its fractions exhibited remarkable inhibition in dose dependant manner in the antinociceptive and antiinflammatory investigations. The antipyretic results of MEBS and DMBS were close to the standard drug indomethacin. Investigation of the thrombolytic effect of MEBS, CTBS, DMBS, and BTBS revealed notable clot-lytic potentials. Besides, the phenolic compounds of the plant extracts revealed strong binding affinity to the COX-1, COX-2, mPGES-1 and plasminogen activator enzymes. To recapitulate, based on the research work, Bauhinia scandens L. stem and its phytochemicals can be considered as prospective wellsprings for novel drug development and discovery by future researchers.

The fibrinolytic system enables the onset of Plasmodium infection in the mosquito vector and the mammalian host

Plasmodium parasites must migrate across proteinaceous matrices to infect the mosquito and vertebrate hosts. Plasmin, a mammalian serine protease, degrades extracellular matrix proteins allowing cell migration through tissues. We report that Plasmodium gametes recruit human plasminogen to their surface where it is processed into plasmin by corecruited plasminogen activators. Inhibition of plasminogen activation arrests parasite development early during sexual reproduction, before ookinete formation. We show that increased fibrinogen and fibrin in the blood bolus, which are natural substrates of plasmin, inversely correlate with parasite infectivity of the mosquito. Furthermore, we show that sporozoites, the parasite form transmitted by the mosquito to humans, also bind plasminogen and plasminogen activators on their surface, where plasminogen is activated into plasmin. Surface-bound plasmin promotes sporozoite transmission by facilitating parasite migration across the extracellular matrices of the dermis and of the liver. The fibrinolytic system is a potential target to hamper Plasmodium transmission.

Methanol soluble fraction of fruits of Annona muricata possesses significant antidiarrheal activities

Medicinal plants are the major sources of traditional treatment of disease in Indian subcontinent due to abundant presence of plants and vast side effects of synthetic drug. The present study was subjected to observe in vitro thrombolytic, antibacterial, and in vivo antidiarrheal activities of methanol soluble fraction of fruits of Annona muricata. In thrombolytic activity assay, various concentrations (2 ─ 10 mg/ml) of methanol soluble fraction was used and dose dependently less potent activity was found. The maximum clot lysis 18.33% (p* < 0.05) was achieved at 10 mg/ml of methanolic fruit extract, whereas standard drug streptokinase showed 55.50% (p*** < 0.001) clot lysis. In antibacterial assay, disc diffusion method was used comprising two gram positive (S. aureus and Micrococcus luteus) and two gram negative (E. coli and P. aeruginosa) bacteria. None of four (0.25, 0.5, 1, and 5 mg/disc) concentration of fruit extract showed antibacterial potentiality, whereas standard amikacin (3 mg/disc) revealed strong antibacterial activities (=~ 23 ─ 24 mm of MIC). To evaluate antidiarrheal activity, castor oil induced diarrhea was created in Swiss albino mice and different doses (100, 200, and 400 mg/kgbw) of fruit extract was introduced post orally. All of three different doses of fruit extract showed significant (p < 0.05 ─ 0.001) antidiarrheal activities. Notably, the percent inhibition of diarrhea by methanolic extract of fruits of Annona muricata was found to be 58.38% at a dose of 400 mg/kgbw. The effect of vehicle saline (10 ml/kgbw) was considered as control and loperamide (5 mg/kgbw) as standard that provided 67.01% inhibition of diarrhea. The results suggest that, the fruits of Annona muricata possess potent antidiarrheal properties, providing scientific basis of using the plant parts in the treatment of diarrheal disease.

Ascertainment of pharmacological activities of Allamanda neriifolia Hook and Aegialitis rotundifolia Roxb used in Bangladesh: An in vitro study

The present study was cherished to investigate in vitro thrombolytic, membrane stabilizing and antibacterial activities of Allamanda neriifolia and Aegialitis rotundifolia. Different types methanolic extracts of these two medicinal plants were tested for determining membrane stabilizing activity at a hypotonic solution and heat induce condition by comparing with reference standard acetyl salicylic acid (0.10 mg/mL), where thrombolytic activity assessment was done by employing Streptokinase as standard drug. Finally, antibacterial activity was performed against Staphylococcus aureus as a Gram-positive (+ve) and Salmonella typhi, Escherichia coli and Pseudomonas aeruginosa as Gram negative (−ve) bacteria by using disc diffusion method. In case of membrane stabilizing studies, crude methanolic extracts of A. neriifolia at 10 mg/ml concentration, more importantly, showed 45.80% & 23.52% whereas 10 mg/ml concentration of A. rotundifolia more significantly (p < 0.01) produced 38.40% and 27.04% inhibition of hemolysis for both experimental conditions. Dose-dependently increased activity was found in the thrombolytic study where 10 mg/ml concentration of both A. neriifolia and A. rotundifolia more significantly (p < 0.01) showed 41.91% and 32.76% lysis of clot respectively by in vitro clot lysis assay method. Crude methanolic extracts of A. rotundifolia did not show any suitable antibacterial property against the test bacteria. However, the gram positive (+ve) bacteria also seemed resistant against A. neriifolia extract but this crude methanolic extracts was found to generate moderate antibacterial action against gram-negative (−ve) bacteria. The obtained results confirmed the presence of thrombolytic, membrane stabilizing activity for both plant extract along with moderate antibacterial activity for A. neriifolia.

Antithrombotic and cytotoxic activities of four Bangladeshi plants and PASS prediction of their isolated compounds

BACKGROUND

This study aims to investigate whether tested organic extracts possess antithrombotic properties with minimal or no toxicity and to predict the activity of some of their isolated compounds.

METHODS

An in vitro thrombolytic model was used to check the clot lysis effect of four Bangladeshi herbal extracts viz., roots of Curculigo recurvata W.T. Aiton (Satipata), leaf of Amorphophallus bulbifer Roxb. (Olkachu), leaf of Phyllanthus sikkimensis Muell. Arg., and whole plant of Thunbergia grandiflora Roxb. (Nillata) using streptokinase as a positive control and water as a negative control. Cytotoxicity was screened by brine shrimp lethality bioassay using vincristine sulfate as positive control. In silico prediction of activity spectra for substances (PASS) prediction was applied for phytoconstituents, namely, nyasicoside, glucomannan, grandifloric acid, serine, and alanine.

RESULTS

Using an in vitro thrombolytic model, C. recurvata, A. bulbifer, P. sikkimensis, and T. grandiflora showed 28.10±1.64%, 42.47±1.96%, 32.86±1.92%, and 25.51±1.67% of clot lysis, respectively. Reference drug streptokinase exhibited 75.00±3.04% clot lysis. Examined herbs showed significant (p<0.001) percentage (%) of clot lysis compared to negative control. In brine shrimp cytotoxic assay, C. recurvata, A. bulbifer, P. sikkimensis, and T. grandiflora showed LC50 values 210.64±3.44, 98.51±1.47, 187.29±2.01, and 386.43±3.02 μg/mL, respectively, with reference to vincristine sulfate (LC50 0.76±0.04). PASS predicted that examined phytoconstituents have a wide range of biological activity.

CONCLUSIONS

Through our study it was found that A. bulbifer and P. sikkimensis could be considered as very promising and beneficial thrombolytic agents.

Anti-inflammatory, anti-diarrheal, thrombolytic and cytotoxic activities of an ornamental medicinal plant: Persicaria orientalis

BACKGROUND

Persicaria orientalis, an ornamental medicinal plant, has been used in traditional medicine for the treatment of various diseases. Although the plant is reported to have some important pharmacological effects, many medicinal values remain unidentified. Our objective was to evaluate the anti-inflammatory, anti-diarrheal, thrombolytic, and cytotoxic properties of the methanol extract of P. orientalis leaves (Po-MeOH).

METHODS

Anti-inflammatory activity was measured by the inhibition of hypotonicity-induced human red blood cell hemolysis and albumin denaturation technique in vitro of Po-MeOH. Diarrheal episodes were examined in mice with castor oil-induced diarrhea. The clot lysis and brine shrimp lethality bioassay in vitro were used to evaluate the thrombolytic and cytotoxic activities of the plant extract, respectively.

RESULTS

Using in vitro anti-inflammatory models, the results demonstrated that Po-MeOH at the five different dose ranges from 31.25 to 500 μg/mL significantly (p<0.05) protected (0.98%-50.71%) the erythrocyte membrane against lysis induced by hypotonic medium solution and protein denaturation (38.27%-79.22%) of bovine albumin, respectively. The extract exhibited a significant reduction of severity (75.17%) of castor oil-induced diarrhea in mice at the highest dose of 400 mg/kg compared to loperamide (82.06%) at 5 mg/kg. Po-MeOH also showed 33.14% clot lytic activity in the thrombolytic test and cytotoxicity with LC50 value 58.91 μg/mL in the brine shrimp bioassay.

CONCLUSIONS

These findings suggest that Po-MeOH has significant anti-inflammatory and anti-diarrheal effects along with moderate thrombolytic and lower cytotoxic properties that may warrant the further exploration.

Effects of organic extracts and their different fractions of five Bangladeshi plants on in vitro thrombolysis

BACKGROUND

The increasingly high incidence of ischemic stroke caused by thrombosis of the arterial vessels is one of the major factors that threaten people's health and lives in the world. The present treatments for thrombosis are still unsatisfactory. Herbal preparations have been used since ancient times for the treatment of several diseases. The aim of this study was to investigate whether herbal preparations possess thrombolytic activity or not.

METHODS

An in vitro thrombolytic model was used to check the clot lysis effect of the crude extracts and fractions of five Bangladeshi plant viz., Trema orientalis L., Bacopa monnieri L., Capsicum frutescens L., Brassica oleracea L. and Urena sinuata L. using streptokinase as a positive control and water as a negative control. Briefly, venous blood drawn from twenty healthy volunteers was allowed to form clots which were weighed and treated with the test plant materials to disrupt the clots. Weight of clot after and before treatment provided a percentage of clot lysis.

RESULTS

Using an in vitro thrombolytic model, different fractions of five Bangladeshi medicinal plants namely T. orientalis, B. monnieri, C. frutescens, B. oleracea and U. sinuata showed various range of clot lysis activity. Chloroform fractions of T. orientalis, B. monnieri, C. frutescens, B. oleracea and U. sinuata showed highest significant (P < 0.05 and P < 0.001) clot lysis activity viz., 46.44 ± 2.44%, 48.39 ± 10.12%, 36.87 ± .27%, 30.24 ± 0.95% and 47.89 ± 6.83% respectively compared with positive control standard streptokinase (80.77 ± 1.12%) and negative control sterile distilled water (5.69 ± 3.09%). Other fractions showed moderate to low clot lysis activity. Order of clot lysis activity was found to be: Streptokinase > Chloroform fractions > Methanol (crude) extract > Hydro-methanol fractions > Ethyl acetate fractions > n-hexane fractions > Water.

CONCLUSIONS

Our study suggests that thrombolytic activity of T. orientalis, B. monnieri and U. sinuata could be considered as very promising and beneficial for the Bangladeshi traditional medicine. Lower effects of other extracts might suggest the lack of bio-active components and/or insufficient quantities in the extract. In vivo clot dissolving property and active component(s) of T. orientalis and B. monnieri for clot lysis could lead the plants for their therapeutic uses. However, further work will establish whether or not, chloroform soluble phytochemicals from these plants could be incorporated as a thrombolytic agent for the improvement of the patients suffering from atherothrombotic diseases.

In vivo analgesic, antipyretic, and anti-inflammatory potential in Swiss albino mice and in vitro thrombolytic activity of hydroalcoholic extract from Litsea glutinosa leaves

Background

The study was conducted to evaluate the in vitro thrombolytic activity, and in vivo analgesic, anti-inflammatory and antipyretic potentials of different hydrocarbon soluble extracts of Litsea glutinosa leaves for the first time widely used in the folkloric treatments in Bangladesh. This work aimed to create new insights on the fundamental mechanisms of the plant extracts involved in these activities.

Results

In thrombolytic activity assay, a significant clot disruption was observed at dose of 1 mg/mL for each of the extracts (volume 100 μL) when compared to the standard drug streptokinase. The n-hexane, ethyl acetate, chloroform, and crude methanolic extracts showed 32.23 ± 0.26, 37.67 ± 1.31, 43.13 ± 0.85, and 46.78 ± 0.9% clot lysis, respectively, whereas the positive control streptokinase showed 93.35 ± 0.35% disruption at the dose of 30,000 I.U. In hot plate method, the highest pain inhibitory activity was found at a dose of 500 mg/kg of crude extract (15.54 ± 0.37 sec) which differed significantly (P <0.01 and P <0.001) with that of the standard drug ketorolac (16.38 ± 0.27 sec). In acetic acid induced writhing test, the crude methanolic extract showed significant (P <0.01 and P <0.001) analgesic potential at doses 250 and 500 mg/kg body weight (45.98 and 56.32% inhibition, respectively), where ketorolac showed 64.36% inhibition. In anti-inflammatory activity test, the crude methanolic extract showed significant (P <0.001) potential at doses 250 and 500 mg/kg body weight (1.51 ± 0.04 and 1.47 ± 0.03 mm paw edema, respectively), where ketorolac showed 1.64 ± 0.05 mm edema after 3 h of carrageenan injection. In antipyretic activity assay, the crude extract showed notable reduction in body temperature (32.78 ± 0.46°C) at dose of 500 mg/kg-body weight, when the standard (at dose 150 mg/kg-body weight) exerted 33.32 ± 0.67°C temperature after 3 h of administration.

Conclusions

Our results yield that the crude hydroalcoholic extract has better effects than the other in all trials. In the context, it can be said that the leaves of L. glutinosa possess remarkable pharmacological effects, and justify its traditional use as analgesic, antipyretic, anti-inflammatory, and thrombolytic agent.

The plasminogen activation system in periodontal tissue (Review)

The plasminogen activation system (PAS) plays an essential role in tissue proteolysis in physiological and pathological processes. Periodontitis is a chronic infection associated with increased proteolysis driven by plasminogen activation. In this comprehensive review, we summarise the effects of PAS in wound healing, tissue remodelling, inflammation, bacterial infection, and in the initiation and progression of periodontal disease. Specifically, we discuss the role of plasminogen activators (PAs), including urokinase PA (uPA), tissue-type PA (tPA), PA inhibitor type 1 (PAI-1) and 2 (PAI-2) and activated plasminogen in periodontal tissue, where their concentrations can reach much higher values than those found in other parts of the body. We also discuss whether PA deficiencies can have effects on periodontal tissue. We conclude that in periodontal disease, PAS is unbalanced and equalizing its function can improve the clinical periodontal tissue condition.

Glycoproteomic analysis of serum from patients with gastric precancerous lesions

Gastric cancer is preceded by a carcinogenesis pathway that includes gastritis caused by Helicobacter pylori infection, chronic atrophic gastritis that may progress to intestinal metaplasia (IM), dysplasia, and ultimately gastric carcinoma of the more common intestinal subtype. The identification of glycosylation changes in circulating serum proteins in patients with precursor lesions of gastric cancer is of high interest and represents a source of putative new biomarkers for early diagnosis and intervention. This study applies a glycoproteomic approach to identify altered glycoproteins expressing the simple mucin-type carbohydrate antigens T and STn in the serum of patients with gastritis, IM (complete and incomplete subtypes), and control healthy individuals. The immunohistochemistry analysis of the gastric mucosa of these patients showed expression of T and STn antigens in gastric lesions, with STn being expressed only in IM. The serum glycoproteomic analysis using 2D-gel electrophoresis, Western blot, and MALDI-TOF/TOF mass spectrometry led to the identification of circulating proteins carrying these altered glycans. One of the glycoproteins identified was plasminogen, a protein that has been reported to play a role in H. pylori chronic infection of the gastric mucosa and is involved in extracellular matrix modeling and degradation. Plasminogen was further characterized and showed to carry STn antigens in patients with gastritis and IM. These results provide evidence of serum proteins displaying abnormal O-glycosylation in patients with precursor lesions of gastric carcinoma and include a panel of putative targets for the non-invasive clinical diagnosis of individuals with gastritis and IM.

Effects of organic extracts of six Bangladeshi plants on in vitro thrombolysis and cytotoxicity

BACKGROUND

Thrombus formed in blood vessels lead to atherothrombotic diseases such as myocardial or cerebral infarction. Thrombolytic agents are used to dissolve the already formed clots in the blood vessels; however, these drugs sometimes cause serious and fatal consequences. Herbal preparations have been used since ancient times for the treatment of several diseases although they show little toxicity in some cases. Aqueous extracts of herbs used in thrombolysis have been reported before with cytotoxic data, however, the organic extracts of herbs have not been documented. This study aims to investigate whether organic extracts possess thrombolytic properties with minimal or no toxicity.

METHODS

An in vitro thrombolytic model was used to check the clot lysis effect of six Bangladeshi herbal extracts viz., Ageratum conyzoides L., Clausena suffruticosa, Leea indica (Burm.f.) Merr., Leucas aspera Willd., Senna sophera L. Roxb., and Solanum torvum Swartz. using streptokinase as a positive control and water as a negative control. Briefly, venous blood drawn from twenty healthy volunteers was allowed to form clots which were weighed and treated with the test plant materials to disrupt the clots. Weight of clot after and before treatment provided a percentage of clot lysis. Cytotoxicity was screened by brine shrimp lethality bioassay using vincristine sulfate as positive control.

RESULTS

Using an in vitro thrombolytic model, Ageratum conyzoides, Clausena suffruticosa, Leea indica, Leucas aspera, Senna sophera and Solanum torvum showed 18.12 ± 2.34%, 48.9 ± 2.44%, 39.30 ± 0.96%, 37.32 ± 2.00%, 31.61 ± 2.97% and 31.51 ± 0.57% and clot lysis respectively. Among the herbs studied Clausena suffruticosa, Leea indica and Leucas aspera showed very significant (p < 0.0001) percentage (%) of clot lysis compared to reference drug streptokinase (75.00 ± 3.04%). In brine shrimp cytotoxic assay, the extracts Ageratum conyzoides, Clausena suffruticosa, Leea indica, Leucas aspera, Senna sophera and Solanum torvum showed LC50 values 508.86 ± 6.62,41.16 ± 1.26, 2.65 ± 0.16, 181.67 ± 1.65, 233.37 ± 7.74 and 478.40 ± 3.23 μg/ml, respectively, with reference to vincristine sulfate (LC50 0.76 ± 0.04).

CONCLUSION

Through our study it was found that Clausena suffruticosa, Leea indica and Leucas aspera possessed effective thrombolytic properties whereas Senna sophera and Solanum torvum showed moderate to mild thrombolytic effects while Ageratum conyzoides showed no significant effect. No extract was found cytoxic compared to positive control. Clausena suffruticosa, Leea indica and Leucas aspera could be incorporated as a thrombolytic agent with in vivo effects to improve the atherothrombotic patients. However, Clausena suffruticosa could be the best one to use in this purpose.

Bacterial plasminogen receptors utilize host plasminogen system for effective invasion and dissemination

In order for invasive pathogens to migrate beyond the site of infection, host physiological barriers such as the extracellular matrix, the basement membrane, and encapsulating fibrin network must be degraded. To circumvent these impediments, proteolytic enzymes facilitate the dissemination of the microorganism. Recruitment of host proteases to the bacterial surface represents a particularly effective mechanism for enhancing invasiveness. Plasmin is a broad spectrum serine protease that degrades fibrin, extracellular matrices, and connective tissue. A large number of pathogens express plasminogen receptors which immobilize plasmin(ogen) on the bacterial surface. Surface-bound plasminogen is then activated by plasminogen activators to plasmin through limited proteolysis thus triggering the development of a proteolytic surface on the bacteria and eventually assisting the spread of bacteria. The host hemostatic system plays an important role in systemic infection. The interplay between hemostatic processes such as coagulation and fibrinolysis and the inflammatory response constitutes essential components of host defense and bacterial invasion. The goal of this paper is to highlight mechanisms whereby pathogenic bacteria, by engaging surface receptors, utilize and exploit the host plasminogen and fibrinolytic system for the successful dissemination within the host.

Plasminogen acquisition and activation at the surface of leptospira species lead to fibronectin degradation

Pathogenic Leptospira species are the etiological agents of leptospirosis, a widespread disease of human and veterinary concern. In this study, we report that Leptospira species are capable of binding plasminogen (PLG) in vitro. The binding to the leptospiral surface was demonstrated by indirect immunofluorescence confocal microscopy with living bacteria. The PLG binding to the bacteria seems to occur via lysine residues because the ligation is inhibited by addition of the lysine analog 6-aminocaproic acid. Exogenously provided urokinase-type PLG activator (uPA) converts surface-bound PLG into enzymatically active plasmin, as evaluated by the reaction with the chromogenic plasmin substrate d-Val-Leu-Lys 4-nitroanilide dihydrochloridein. The PLG activation system on the surface of Leptospira is PLG dose dependent and does not cause injury to the organism, as cellular growth in culture was not impaired. The generation of active plasmin within Leptospira was observed with several nonvirulent high-passage strains and with the nonpathogenic saprophytic organism Leptospira biflexa. Statistically significant higher activation of plasmin was detected with a low-passage infectious strain of Leptospira. Plasmin-coated virulent Leptospira interrogans bacteria were capable of degrading purified extracellular matrix fibronectin. The breakdown of fibronectin was not observed with untreated bacteria. Our data provide for the first time in vitro evidence for the generation of active plasmin on the surface of Leptospira, a step that may contribute to leptospiral invasiveness.

Characteristics of plasminogen binding to Trypanosoma cruzi epimastigotes

The binding constants of the interaction between plasminogen and Trypanosoma cruzi epimastigotes were determined. An indirect method in which the bound plasminogen is detached from the cell by epsilon-aminocaproic acid and a direct method through biotinylated plasminogen were used. The analyses revealed a dissociation constant (Kd) from 0.4 to 1.2microM, these values being compatible with recognition in vivo. Moreover, epimastigotes from the gut of Rhodnius prolixus were able to bind plasminogen from the blood meal. Fragments derived from elastase digestion of plasminogen were tested for their ability to bind T. cruzi cells. The fragment with highest ability to interact with the parasite was miniplasminogen that bound in a concentration-dependent and saturable manner with a Kd similar to that for plasminogen. This binding was inhibited by epsilon-aminocaproic acid indicating that the lysine-binding site of kringle 5 may be responsible for the interaction of plasminogen with T. cruzi.

Effect of Fagonia Arabica (Dhamasa) on in vitro thrombolysis

BACKGROUND

Atherothrombotic diseases such as myocardial or cerebral infarction are serious consequences of the thrombus formed in blood vessels. Thrombolytic agents are used to dissolve the already formed clots in the blood vessels; however, these drugs have certain limitations which cause serious and sometimes fatal consequences. Herbal preparations have been used since ancient times for the treatment of several diseases. Herbs and their components possessing antithrombotic activity have been reported before; however, herbs that could be used for thrombolysis has not been reported so far. This study's aim was to investigate whether herbal preparations (aqueous extract) possess thrombolytic activity or not.

METHODS

An in vitro thrombolytic model was used to check the clot lysis effect of six aqueous herbal extracts viz., Tinospora cordifolia, Rubia cordifolia, Hemidesmus indicus, Glycyrrhiza glabra Linn, Fagonia Arabica and Bacopa monnieri Linn along with Streptokinase as a positive control and water as a negative control.

RESULTS

Using an in vitro thrombolytic model, Tinospora cordifolia, Rubia cordifolia, Hemidesmus indicus, Glycyrrhiza glabra Linn, Fagonia Arabica and Bacopa monnieri Linn showed 19.3%, 14.5%, 20.3%, 17.8%, 75.6% and 41.8% clot lysis respectively . Among the herbs studied Fagonia arabica showed significant % of clot lysis (75.6%) with reference to Streptokinase (86.2%).

CONCLUSION

Through our study it was found that Dhamasa possesses thrombolytic properties that could lyse blood clots in vitro; however, in vivo clot dissolving properties and active component(s) of Dhamasa for clot lysis are yet to be discovered. Once found Dhamasa could be incorporated as a thrombolytic agent for the improvement of patients suffering from Atherothrombotic diseases.

Bacterial metastasis: the host plasminogen system in bacterial invasion

Several pathogenic bacterial species intervene with the mammalian proteolytic plasminogen-plasmin system. Recent developments have been made in understanding the structure and the virulence-associated functions of bacterial plasminogen receptors and activators, in particular by using plasminogen-deficient or transgenic gain-of-function mice. Bacteria can affect the regulation of the plasminogen system by degrading circulating plasmin inhibitors and by influencing the expression levels of mammalian plasminogen activators and activation inhibitors. Interaction with the plasminogen system promotes damage of extracellular matrices as well as bacterial spread and organ invasion during infection, suggesting common mechanisms in migration of eukaryotic and prokaryotic cells.

Molecular cloning and characterization of two Helicobacter pylori genes coding for plasminogen-binding proteins

Helicobacter pylori binds a number of host cell proteins, including the plasma protein plasminogen, which is the proenzyme of the serine protease plasmin. Two H. pylori plasminogen-binding proteins have been described; however, no genes were identified. Here we report the use of a phage display library to clone two genes from the H. pylori CCUG 17874 genome that mediate binding to plasminogen. DNA sequence analysis of one of these genes revealed 96.6% homology with H. pylori 26695 HP0508. A subsequent database search revealed that the amino acid sequence of a lysine-rich C-terminal segment of HP0508 is identical to the C terminus of HP0863. Recombinant proteins expressed from HP0508 and HP0863 bound plasminogen specifically and in a lysine-dependent manner. We designate these genes pgbA and pgbB, respectively. These proteins are expressed by a variety of H. pylori strains, have surface-exposed domains, and do not inhibit plasminogen activation. These results indicate that pgbA and pgbB may allow H. pylori to coat its exterior with plasminogen, which subsequently can be activated to plasmin. The surface acquisition of protease activity may enhance the virulence of H. pylori.

Candida albicans binds human plasminogen: identification of eight plasminogen-binding proteins

Several microbial pathogens augment their invasive potential by binding and activating human plasminogen to generate the proteolytic enzyme plasmin. Yeast cells and cell wall proteins (CWP) of the human pathogenic fungus Candida albicans bound plasminogen with a K(d) of 70 +/- 11 nM and 112 +/- 20 nM respectively. Bound plasminogen could be activated to plasmin by mammalian plasminogen activators; no C. albicans plasminogen activator was detected. Binding of plasminogen to CWP and whole cells was inhibited by epsilon ACA, indicating that binding was predominantly to lysine residues. Candida albicans mutant strains defective in protein glycosylation did not show altered plasminogen binding, suggesting that binding was not mediated via a surface lectin. Binding was sensitive to digestion by basic carboxypeptidase, implicating C-terminal lysine residues in binding. Proteomic analysis identified eight major plasminogen-binding proteins in isolated CWP. Five of these (phosphoglycerate mutase, alcohol dehydrogenase, thioredoxin peroxidase, catalase, transcription elongation factor) had C-terminal lysine residues and three (glyceraldehyde-3-phosphate dehydrogenase, phosphoglycerate kinase and fructose bisphosphate aldolase) did not. Activation of plasminogen could potentially increase the capacity of this pathogenic fungus for tissue invasion and necrosis. Although surface-bound plasmin(ogen) degraded fibrin, no direct evidence for a role in invasion of endothelial matrix or in penetration and damage of endothelial cells was found.

Helicobacter pylori interactions with host serum and extracellular matrix proteins: potential role in the infectious process

Helicobacter pylori, a gram-negative spiral-shaped bacterium, specifically colonizes the stomachs of humans. Once established in this harsh ecological niche, it remains there virtually for the entire life of the host. To date, numerous virulence factors responsible for gastric colonization, survival, and tissue damage have been described for this bacterium. Nevertheless, a critical feature of H. pylori is its ability to establish a long-lasting infection. In fact, although good humoral (against many bacterial proteins) and cellular responses are observed, most infected persons are unable to eradicate the infection. A large body of evidence has shown that the interaction between H. pylori and the host is very complex. In addition to the effect of virulence factors on colonization and persistence, binding of specialized bacterial proteins, known as receptins, to certain host molecules (ligands) could explain the success of H. pylori as a chronically persisting pathogen. Some of the reported interactions are of high affinity, as revealed by their calculated dissociation constant. This review examines the binding of host proteins (serum and extracellular matrix proteins) to H. pylori and considers the significance of these interactions in the infectious process. A more thorough understanding of the kinetics of these receptin interactions could provide a new approach to preventing deeper tissue invasion in H. pylori infections and could represent an alternative to antibiotic treatment.

A study of the interaction between Helicobacter pylori and components of the human fibrinolytic system

The interaction of plasminogen, tissue plasminogen activator (t-PA) and urokinase with a clinical strain of Helicobacter pylori was studied. Plasminogen bound to the surface of H. pylori cells in a concentration-dependent manner and could be activated to the enzymatic form, plasmin, by t-PA. Affinity chromatography assays revealed a plasminogen-binding protein of 58.9 kDa in water extracts of surface proteins. Surface-associated plasmin activity, detected with the chromogenic substrate CBS 00.65, was observed only when plasminogen and an exogenous activator were added to the cell suspension. The two physiologic plasminogen activators, t-PA and urokinase, were also shown to bind to and remain active on the surface of bacterial cells. epsilon-Aminocaproic acid caused partial inhibition of t-PA binding, suggesting that the kringle 2 structure of this activator is involved in the interaction with surface receptors. The activation of plasminogen by t-PA, but not urokinase, strongly depended on the presence of cells and a 25-fold enhancer effect on the initial velocity of activation by t-PA compared to urokinase was established. Furthermore, a relationship between cell concentration and the initial velocity of activation was demonstrated. These findings support the concept that plasminogen activation by t-PA on the bacterial surface is a surface-dependent reaction which offers catalytic advantages.

Helicobacter pylori interactions with plasminogen

Helicobacter pylori is the causative agent of chronic gastritis, peptic ulcer, and gastric malignancies. A number of virulence factors have been described including several adhesins, a cytotoxin, neutrophil-activating protein, and expression of binding of extracellular matrix proteins, like collagen type IV, laminin, and vitronectin. H. pylori strains commonly express binding of soluble plasminogen. Coccoid forms also express binding. Plasminogen binding was optimal at pH 7.0. The binding is mediated by two cell surface proteins of 42 and 57 kDa. Scatchard plot analysis showed a straight line with a K(d) of 7 x 10(-7) M. Lysine and E-aminocaproic acid inhibited binding. The binding domain on the plasminogen molecule is the fifth kringle, miniplasminogen. Plasminogen is converted to plasmin by tissue plasminogen activator. During H. pylori infection the activity of tissue plasminogen activator is decreased and that of urokinase increased. This is reversed after eradication therapy. The plasminogen binding and conversion to plasmin is the only proteolytic activity of H. pylori, and may enhance tissue penetration and be involved in carcinogenesis.

Interaction of group A streptococci with human plasmin(ogen) under physiological conditions

A series of methods for analyzing the interaction of group A streptococci with the human plasminogen system are described. Examples of group A streptococcal isolates capable of assembling surface plasminogen activator activity when grown in human plasma are presented and the key requirements for this process are evaluated. The stabilities of cell-associated plasmin and plasminogen activator complexes are compared and a model for the interaction of group A streptococci with the plasminogen system in an infected host is presented.

Bacterial proteinases as targets for the development of second-generation antibiotics

The emergence of bacterial pathogen resistance to common antibiotics strongly supports the necessity to develop alternative mechanisms for combating drug-resistant forms of these infective organisms. Currently, few pharmaceutical companies have attempted to investigate the possibility of interrupting metabolic pathways other than those that are known to be involved in cell wall biosynthesis. In this review, we describe multiple, novel roles for bacterial proteinases during infection using, as a specific example, the enzymes from the organism Porphyromonas gingivalis, a periodontopathogen, which is known to be involved in the development and progression of periodontal disease. In this manner, we are able to justify the concept of developing synthetic inhibitors against members of this class of enzymes as potential second-generation antibiotics. Such compounds could not only prove valuable in retarding the growth and proliferation of bacterial pathogens but also lead to the use of this class of inhibitors against invasion by other infective organisms.

Acquisition of plasmin activity by Fusobacterium nucleatum subsp. nucleatum and potential contribution to tissue destruction during periodontitis

Fusobacterium nucleatum subsp. nucleatum has been associated with a variety of oral and nonoral infections such as periodontitis, pericarditis, bone infections, and brain abscesses. Several studies have shown the role of plasmin, a plasma serine protease, in increasing the invasive capacity of microorganisms. In this study, we investigated the binding of human plasminogen to F. nucleatum subsp. nucleatum, and its subsequent activation into plasmin. Plasminogen-binding activity of bacterial cells was demonstrated by a solid-phase dot blot assay using an anti-plasminogen antibody. The binding activity was heat resistant and involved cell-surface lysine residues since it was abolished in the presence of the lysine analog epsilon-aminocaproic acid. Activation of plasminogen-coated bacteria occurred following incubation with either streptokinase, urokinase-type plasminogen activator (u-PA), or a Porphyromonas gingivalis culture supernatant. In the case of the P. gingivalis culture supernatant, a cysteine protease was likely involved in the activation. The plasmin activity generated on the cell surface of F. nucleatum subsp. nucleatum could be inhibited by aprotinin. Activation of plasminogen by u-PA was greatly enhanced when plasminogen was bound to bacteria rather than in a free soluble form. u-PA-activated plasminogen-coated F. nucleatum subsp. nucleatum was found to degrade fibronectin, as determined by sodium dodecyl sulfate-polyacrylamide gel electrophoresis. Tissue inhibitor of metalloproteinase-1 was also degraded by the plasmin activity generated on the bacterial cells. This study suggests a possible role for plasminogen, which is present in affected periodontal sites, in promoting tissue destruction and invasion by nonproteolytic bacteria such as F. nucleatum subsp. nucleatum.

Activation of interstitial collagenase, MMP-1, by Staphylococcus aureus cells having surface-bound plasmin: a novel role of plasminogen receptors of bacteria

Plasmin, the enzymatically active form of plasminogen, can activate several matrix metalloproteinases (MMPs). In this study, we investigated the activation of MMP-1, one of the major interstitial collagenases, by plasmin which was generated on the surface of Staphylococcus aureus cells. Plasmin bound to plasminogen receptors on S. aureus degraded the major (125)I-labeled 55-kDa proMMP-1 into the 42-kDa form corresponding to the size of active MMP-1. MMP-1 formed by S. aureus-bound plasmin was also enzymatically active as judged by digestion of the synthetic collagenase substrate, DNP-Pro-Leu-Gly-Leu-Trp-Ala-D-Arg-NH(2). The finding that, in MMP-1 molecules generated either by soluble plasmin or by S. aureus-bound plasmin, the amino-terminal amino acid sequences were identical indicated that the activation mechanisms of the two plasmin forms do not differ from each other. The present observations emphasise and broaden the physiological importance of bacterial plasminogen receptors. In addition to direct proteolytic effects on components of the extracellular matrix, receptor-bound plasmin is also capable of initiating an MMP-1-dependent matrix-degrading enzymatic cascade.