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1.
Sci Rep ; 14(1): 9322, 2024 04 23.
Article in English | MEDLINE | ID: mdl-38654034

ABSTRACT

Dengue virus (DENV) infection can lead to severe outcomes through a virus-induced cytokine storm, resulting in vascular leakage and inflammation. An effective treatment strategy should target both virus replication and cytokine storm. This study identified Kaempferia galanga L. (KG) extract as exhibiting anti-DENV activity. The major bioactive compound, ethyl-p-methoxycinnamate (EPMC), significantly reduced DENV-2 infection, virion production, and viral protein synthesis in HepG2 and A549 cells, with half-maximal effective concentration (EC50) values of 22.58 µM and 6.17 µM, and impressive selectivity indexes (SIs) of 32.40 and 173.44, respectively. EPMC demonstrated efficacy against all four DENV serotypes, targeting the replication phase of the virus life cycle. Importantly, EPMC reduced DENV-2-induced cytokines (IL-6 and TNF-α) and chemokines (RANTES and IP-10), as confirmed by immunofluorescence and immunoblot analyses, indicating inhibition of NF-κB activation. EPMC's role in preventing excessive inflammatory responses suggests it as a potential candidate for dengue treatment. Absorption, distribution, metabolism, excretion, and toxicity (ADMET) and drug-likeness for EPMC were predicted using SwissADME and ProTox II servers, showing good drug-like properties without toxicity. These findings highlight KG extract and EPMC as promising candidates for future anti-dengue therapeutics, offering a dual-action approach by inhibiting virus replication and mitigating inflammatory reactions.


Subject(s)
Antiviral Agents , Cinnamates , Dengue Virus , Dengue , Inflammation , NF-kappa B , Virus Replication , Humans , A549 Cells , Antiviral Agents/pharmacology , Cinnamates/pharmacology , Cytokines/metabolism , Dengue/drug therapy , Dengue/virology , Dengue Virus/drug effects , Hep G2 Cells , Inflammation/drug therapy , NF-kappa B/antagonists & inhibitors , NF-kappa B/drug effects , NF-kappa B/metabolism , Signal Transduction/drug effects , Virus Replication/drug effects
2.
J Evid Based Integr Med ; 28: 2515690X231191101, 2023.
Article in English | MEDLINE | ID: mdl-37553989

ABSTRACT

Psoriasis is an incurable, chronic and auto-immune skin disorder with a global prevalence rate of approximately 2-3%. The study investigated the antipsoriasis activities of Deprungsith formulation and its bioactive components and their potential for inhibitory activities on human cytochrome P450 (CYP450). HaCaT and peripheral blood mononuclear cells (PBMCs) from healthy volunteers (n = 9) and psoriasis patients (n = 10) were exposed to Deprungsith formulation (Thai traditional medicine for psoriasis consisting of 16 plants), ethyl p-methoxycinnamate (EPMC), ligustilide and cyclosporin for 24 and 48 h. The antiproliferative, cell apoptosis and cell cycle arrest activities were evaluated using MTT assay and flow cytometry, respectively. The pro-inflammatory cytokine mRNA expression levels were measured using real-time polymerase chain reaction (RT-PCR). The CYP450 inhibitory effect was investigated using a bioluminescent-based CYP450 assay. Deprungsith formulation and the bioactive compounds inhibited HaCaT cells and PBMCs with weak to moderate potencies. EPMC and ligustilide combination produced an additive effect. Most substances arrested cell transition at sub-G1 and S phases, leading to early and late apoptosis induction. With prolonged exposure (48 h), all test substances decreased PBMCs necrosis. The mRNA expression of all pro-inflammatory cytokines was downregulated. Deprungsith formulation, EPMC, ligustilide and ferulic acid inhibited CYP1A2, CYP2C9, CYP2D6 and CYP3A4 activities with weak to moderate potencies. Deprungsith formulation and bioactive components induced cell apoptosis by inhibiting cell transition at specific cell cycle phases, which was correlated with the mRNA downregulation of interleukin (IL-6, IL-12p19, IL-23) and tumor necrosis factor (TNF-α). There is a low risk of potential adverse drug reactions and toxicity due to CYP450 interaction when Deprungsith formulation is concurrently administered with modern medicines.


Subject(s)
Herb-Drug Interactions , Psoriasis , Humans , Plant Extracts/pharmacology , Plant Extracts/therapeutic use , Leukocytes, Mononuclear/metabolism , Cytochrome P-450 Enzyme System/metabolism , Anti-Inflammatory Agents/pharmacology , Anti-Inflammatory Agents/therapeutic use , Psoriasis/drug therapy , Cytokines , RNA, Messenger/therapeutic use
3.
Pathogens ; 12(3)2023 Mar 01.
Article in English | MEDLINE | ID: mdl-36986318

ABSTRACT

There is an inverse relationship between the high incidence of helminth infection and the low incidence of inflammatory disease. Hence, it may be that helminth molecules have anti-inflammatory effects. Helminth cystatins are being extensively studied for anti-inflammatory potential. Therefore, in this study, the recombinant type I cystatin (stefin-1) of Fasciola gigantica (rFgCyst) was verified to have LPS-activated anti-inflammatory potential, including in human THP-1-derived macrophages and RAW 264.7 murine macrophages. The results from the MTT assay suggest that rFgCyst did not alter cell viability; moreover, it exerted anti-inflammatory activity by decreasing the production of proinflammatory cytokines and mediators, including IL-1ß, IL-6, IL-8, TNF-α, iNOS, and COX-2 at the gene transcription and protein expression levels, as determined by qRT-PCR and Western blot analysis, respectively. Further, the secretion levels of IL-1ß, IL-6, and TNF-α determined by ELISA and the NO production level determined by the Griess test were decreased. Furthermore, in Western blot analysis, the anti-inflammatory effects involved the downregulation of pIKKα/ß, pIκBα, and pNF-κB in the NF-κB signaling pathway, hence reducing the translocation from the cytosol into the nucleus of pNF-κB, which subsequently turned on the gene of proinflammatory molecules. Therefore, cystatin type 1 of F. gigantica is a potential candidate for inflammatory disease treatment.

4.
Asian Pac J Cancer Prev ; 23(9): 3093-3101, 2022 Sep 01.
Article in English | MEDLINE | ID: mdl-36172672

ABSTRACT

OBJECTIVES: Cholangiocarcinoma (CCA) is a highly aggressive tumor with a greater risk of distant metastasis. The promising anti-CCA activity and safety profile of Atractylodes lancea (AL) have previously been reported in a series of in vitro, in vivo and clinical studies. The present study investigated the effect of AL extract on apoptosis and metastasis signaling pathways in the Opisthorchis viverrini/dimethylnitrosamine (OV/DMN)-induced CCA hamster model. MATERIALS AND METHODS: Hamster liver tissues were obtained from the four groups (n = 5 per group), i.e., (i) 5-FU treated CCA (40 µg/mL); (ii) CCA; (iii) AL-treated CCA (5,000 mg/kg), and (iv) normal hamsters. Total RNA was isolated, and the expression levels of apoptosis-related and metastasis-related genes were determined by qRT-PCR analysis. RESULTS: The expression levels of p16, caspase-3, caspase-8, caspase-9, Apaf-1, p53 and Eef1a1 were downregulated, while that of the remaining genes were upregulated in CCA hamsters compared with normal hamsters. AL treatment increased the expression of p16, caspase-9, caspase-3, Apaf-1, p53 and E-cadherin and decreased the expression of cyclin D1, cdk4, Bax, Akt/PKB, Bcl-2, Mfge-8, Lass4, S100A6, TGF-ß, Smad-2, Smad-3, Smad-4, MMP-9, and N-cadherin. The expression of Eef1a1 was unchanged. CONCLUSION: The anti-CCA activity of AL in OV/DMN-induced CCA hamsters could be due to the induction of cell cycle arrest at the G1 phase and activation of the apoptosis pathway, resulting in cancer cell death. The activation of the apoptosis pathway mainly involved the intrinsic pathway (activation of caspase-3 and caspase-9 through p53 and Mfge-8 modulation and downregulation of anti-apoptotic genes Akt and Bcl-2). In addition, AL could also inhibit the canonical TGF-ß signaling pathway, MMP-9 and N-cadherin to suppress tumor metastasis.


Subject(s)
Atractylodes , Bile Duct Neoplasms , Cholangiocarcinoma , Opisthorchiasis , Opisthorchis , Animals , Atractylodes/genetics , Atractylodes/metabolism , Bile Duct Neoplasms/chemically induced , Bile Duct Neoplasms/drug therapy , Bile Duct Neoplasms/pathology , Bile Ducts, Intrahepatic/pathology , Cadherins/metabolism , Caspase 3/metabolism , Caspase 8/metabolism , Caspase 9/metabolism , Cholangiocarcinoma/chemically induced , Cholangiocarcinoma/drug therapy , Cholangiocarcinoma/genetics , Cricetinae , Cyclin D1/metabolism , Dimethylnitrosamine , Fluorouracil/therapeutic use , Humans , Matrix Metalloproteinase 9/metabolism , Mesocricetus , Opisthorchiasis/drug therapy , Opisthorchiasis/pathology , Plant Extracts/therapeutic use , Proto-Oncogene Proteins c-akt/metabolism , RNA , Transforming Growth Factor beta/metabolism , Tumor Suppressor Protein p53 , bcl-2-Associated X Protein/metabolism
5.
Sci Rep ; 12(1): 16088, 2022 09 27.
Article in English | MEDLINE | ID: mdl-36168031

ABSTRACT

Severe dengue virus (DENV) infection results from viral replication and dysregulated host immune response, which trigger massive cytokine production/cytokine storm. The result is severe vascular leakage, hemorrhagic diathesis, and organ dysfunction. Subsequent to previously proposing that an ideal drug for treatment of DENV infection should efficiently inhibit both virus production and cytokine storm, we discovered that α-mangostin (α-MG) from the pericarp of the mangosteen fruit could inhibit both DENV infection and cytokine/chemokine production. In this study, we investigated the molecular mechanisms underlying the antiviral and anti-inflammatory effects of α-MG. Time-of-drug-addition and time-of-drug-elimination studies suggested that α-MG inhibits the replication step of the DENV life cycle. α-MG inhibited polymerization activity of RNA-dependent RNA polymerase (RdRp) with IC50 values of 16.50 µM and significantly reduced viral RNA and protein syntheses, and virion production. Antiviral and cytokine/chemokine gene expression profiles of α-MG-treated DENV-2-infected cells were investigated by polymerase chain reaction array. α-MG suppressed the expression of 37 antiviral and cytokine/chemokine genes that relate to the NF-κB signaling pathway. Immunofluorescence and immunoblot analyses revealed that α-MG inhibits NF-κB nuclear translocation in DENV-2-infected cells in association with reduced RANTES, IP-10, TNF-α, and IL-6 production. These results suggest α-MG as a potential treatment for DENV infection.


Subject(s)
Dengue Virus , Dengue , Virus Diseases , Anti-Inflammatory Agents/pharmacology , Antiviral Agents/pharmacology , Antiviral Agents/therapeutic use , Chemokine CCL5 , Chemokine CXCL10 , Cytokine Release Syndrome , Cytokines/metabolism , Dengue/drug therapy , Dengue Virus/physiology , Humans , Inflammation/drug therapy , Interleukin-6/pharmacology , NF-kappa B/metabolism , RNA, Viral , RNA-Dependent RNA Polymerase , Tumor Necrosis Factor-alpha/metabolism , Virus Diseases/drug therapy , Virus Replication , Xanthones
6.
J Vector Borne Dis ; 58(3): 257-264, 2021.
Article in English | MEDLINE | ID: mdl-35170464

ABSTRACT

Background&objectives: Changes in parasite biology, particularly the gametocytogenesis process, could be one of the important contributing factors for worldwide malaria resurgence. The present study investigated the prevalence rates of pretreatment gametocyte carriage and density in Plasmodium falciparum and P. vivax infections in the low malaria-endemic area on the Thai-Myanmar border. METHODS: One hundred and twenty-six blood samples were collected from patients with signs and symptoms of malaria who attended malaria clinics. Malaria positive cases detected by microscopic examination were confirmed by species-specific nested-PCR in 97 (29 and 68 samples for P. falciparum and P. vivax, respectively). RESULTS: The proportion of P. vivax and P. falciparum-infected samples was 70.1: 29.9%. The density in P. falciparum positive samples [median (95%CI): 10,340 (5280-19,200) µ/l] was significantly higher than P. vivax positive samples [4508 (3240-6120) µ/l]. Sixteen out of twenty-nine (55.2%) and 36 out of 68 (52.9%) P. falciparum- and P. vivax-infected samples, respectively, were gametocyte-positive. Gametocyte density in the P. falciparum-infected[124 (69-253) /µl] was significantly higher than that of the P. vivax-infected [54 (45-70)/µl] samples. A significant correlation between gametocyte density and pretreatment parasitemia was only detected in P. falciparum-infected, but not P. vivax-infected samples. INTERPRETATION & CONCLUSION: The observed high prevalence rates of pretreatment gametocyte carriage of both malaria species, which serves as a large malaria reservoir, particularly in P. falciparum infection, could have a significant impact on malaria control in the endemic populations.


Subject(s)
Malaria, Falciparum , Malaria, Vivax , Humans , Malaria, Falciparum/epidemiology , Malaria, Vivax/epidemiology , Myanmar/epidemiology , Plasmodium falciparum , Plasmodium vivax , Thailand
7.
J Integr Med ; 18(4): 326-333, 2020 Jul.
Article in English | MEDLINE | ID: mdl-32418766

ABSTRACT

OBJECTIVE: To evaluate the cytotoxic, apoptotic, mutagenic and immunomodulatory activities of Kaempferia galanga Linn. (KG) extract and ethyl-p-methoxycinnamate (EPMC) in vitro. METHODS: The present study investigated the cytotoxic [using the 3-(4,5-dimethyl-2-thiazolyl)-2,5-diphenyl-2-H-tetrazolium bromide test], apoptotic (using a mitochondrial membrane potential assay), mutagenic (using a micronucleus test) and immunomodulatory (using flow cytometry) activities of the ethanolic extract of KG and its bioactive component, EPMC, against two cholangiocarcinoma (CCA) cell lines, CL-6 and HuCCT1, and one normal human cell line, OUMS-36T-1F. RESULTS: Both KG extract and EPMC exhibited moderate cytotoxic activity against both CCA cells. The cytotoxic activity was supported by their concentration-dependent induction of apoptosis. CL-6 was most sensitive (3-4 fold) and selective to 5-fluorouracil (5-FU), compared with KG extract and EPMC [median half inhibiting concentration (IC50) and selectivity index (SI) were 23.01 µg/mL and 17.32; 78.41 µg/mL and 4.44; 100.76 µg/mL and 2.20, respectively for 5-FU vs. KG extract vs. EPMC]. HuCCT1 was relatively more sensitive and selective to 5-FU and EPMC than KG extract [median IC50 and SI were 66.03 µg/mL and 6.04; 60.90 µg/mL and 3.65; 156.60 µg/mL and 2.23, respectively for 5-FU vs. EPMC vs. KG extract]. EPMC produced relatively potent cytotoxic activity against polymorphonuclear cells (IC50 = 92.20 µg/mL). KG extract and EPMC exhibited concentration-dependent mutagenic activity, as well as inhibition of tumor necrosis factor-α and interleukin-6. CONCLUSION: Considering cytotoxic, apoptotic, immunomodulatory and mutagenic activities, further development of KG as a drug candidate is likely to focus on the oral pharmaceutical formulation of a standardized KG extract rather than isolated compounds.


Subject(s)
Antineoplastic Agents, Phytogenic/pharmacology , Bile Duct Neoplasms , Cholangiocarcinoma , Plant Extracts/pharmacology , Zingiberaceae , Bile Duct Neoplasms/drug therapy , Bile Duct Neoplasms/pathology , Cell Line, Tumor/drug effects , Cholangiocarcinoma/drug therapy , Cholangiocarcinoma/pathology , Humans , Zingiberaceae/chemistry
8.
Drug Metab Pers Ther ; 34(4)2019 12 18.
Article in English | MEDLINE | ID: mdl-32004143

ABSTRACT

Background Marked differences among genotype frequencies (Caucasians, Asians, and Africans) have been observed in cytochrome P450 (CYP) genes. Data on the frequency of pharmacogenetic relevant polymorphisms in Bhutanese population is absent. This study aimed to investigate the frequencies of pharmacogenetic relevant polymorphisms of CYP2C9 (*2 and *3), CYP2C19 (*2 and *3), CYP2D6 (*10), and CYP3A5 (*3) in Bhutanese population. Methods Genotyping was performed in 443 DNA samples using polymerase chain reaction-restriction fragment length polymorphism. Results For CYP2C9, allele frequencies of *2 and *3 variants were 0.339% and 0%, respectively. For CYP2C19, frequencies of *2 and *3 variants were 30.135% and 15.689%, respectively. Allele frequencies of CYP2D6*10 and CYP3A5*3 were 21.332% and 77.314%, respectively. Allele frequencies of CYP2C9*2 are similar to most Asians while CYP2C9*3 was absent. CYP2C19*2 showed a close resemblance to Japanese and Burmese, while CYP2C19*3 is near to Japanese and Korean. CYP2D6*10 is noticeably lower than other Asians. CYP3A5*3 is similar to East Asians (Chinese, Japanese, and Korean). Conclusions The Bhutanese population is polymorphic for these CYP genes, except for CYP2C9*3. Similar to other populations, genetic testing for these genes may, therefore, be helpful to obtain the benefit from pharmacological treatments and prevent adverse drug reactions.


Subject(s)
Cytochrome P-450 CYP2C19/genetics , Cytochrome P-450 CYP2C9/genetics , Cytochrome P-450 CYP2D6/genetics , Cytochrome P-450 CYP3A/genetics , Pharmacogenomic Testing , Polymorphism, Genetic , Alleles , Bhutan , Genotype , Humans
9.
Virus Res ; 240: 180-189, 2017 08 15.
Article in English | MEDLINE | ID: mdl-28864423

ABSTRACT

Since severe dengue virus (DENV) infection in humans associates with both high viral load and massive cytokine production - referred to as "cytokine storm", an ideal drug for treatment of DENV infection should efficiently inhibit both virus production and cytokine expression. In searching for such an ideal drug, we discovered that α-mangostin (α-MG), a major bioactive compound purified from the pericarp of the mangosteen fruit (Garcinia mangostana Linn), which has been used in traditional medicine for several conditions including trauma, diarrhea, wound infection, pain, fever, and convulsion, inhibits both DENV production in cultured hepatocellular carcinoma HepG2 and Huh-7 cells, and cytokine/chemokine expression in HepG2 cells. α-MG could also efficiently inhibit all four serotypes of DENV. Treatment of DENV-infected cells with α-MG (20µM) significantly reduced the infection rates of four DENV serotypes by 47-55%. α-MG completely inhibited production of DENV-1 and DENV-3, and markedly reduced production of DENV-2 and DENV-4 by 100 folds. Furthermore, it could markedly reduce cytokine (IL-6 and TNF-α) and chemokine (RANTES, MIP-1ß, and IP-10) transcription. These actions of α-MG are more potent than those of antiviral agent (ribavirin) and anti-inflammatory drug (dexamethasone). Thus, α-MG is potential to be further developed as therapeutic agent for DENV infection.


Subject(s)
Antiviral Agents/pharmacology , Chemokines/metabolism , Cytokines/metabolism , Dengue Virus/drug effects , Dengue/metabolism , Dengue/virology , Plant Extracts/pharmacology , Xanthones/pharmacology , Chemokines/genetics , Cytokines/genetics , Dengue/drug therapy , Dengue/genetics , Dengue Virus/genetics , Dengue Virus/physiology , Garcinia/chemistry , Humans , Virus Replication/drug effects
10.
Acta Trop ; 173: 17-22, 2017 Sep.
Article in English | MEDLINE | ID: mdl-28495402

ABSTRACT

Inconsistency of reported associations between the tumor necrosis factor-alpha-308 (TNFα-308) polymorphism (rs1800629) and dengue virus infection prompted a meta-analysis, to obtain more precise estimates. A literature search yielded 14 case-control studies. We calculated pooled odds ratios (OR) and 95% confidence intervals in three groups according to severity, dengue fever (DF), dengue hemorrhagic fever (DHF) and dengue (DEN) using standard genetic models. Pooled ORs were subjected to modifier treatment where re-analysis was confined to Hardy-Weinberg compliant (HWC) studies. Heterogeneity of outcomes warranted examining their sources with outlier treatment. In subgroup analysis, we compared Asian and South/Central American (SCA)/Brazilian effects. Overall pooled outcomes yielded no significant effects (OR 0.66-1.44, P=0.08-0.96). In the dominant-codominant model, pooled effects were heterogeneous (I2=47%-71%) which was lost/reduced (I2=0%-43%) when outlier treatment was applied. This also yielded significant associations (OR 0.68-0.77, P=0.02-0.05). Our results are best seen in the Asian subgroup, which in itself already yielded significant effects in DEN (OR 0.62-0.67, P=0.01-0.02). These reduced risk findings were significant from the tests of interaction (P=0.001-0.02) which highlights the protective effects of TNFα-308 among Asians. TNFα-308 effects on dengue are based on significance and non-heterogeneity of the post-outlier outcomes in the dominant and codominant models. Here, pooled effects may also be ethnic specific, where Asians are protected but not SCA. Both modified and Asian effects are up to 38% protective.


Subject(s)
Dengue/genetics , Genetic Predisposition to Disease , Polymorphism, Genetic , Tumor Necrosis Factor-alpha/genetics , Global Health , Humans , Odds Ratio
11.
Int J Mol Med ; 33(3): 515-22, 2014 Mar.
Article in English | MEDLINE | ID: mdl-24424397

ABSTRACT

Macrophage migration inhibitory factor (MIF) is a pro-inflammatory cytokine, secreted from a variety of immune cells, that regulates innate and adaptive immune responses. Elevation of MIF levels in plasma correlates with the severity of inflammatory diseases in humans. Inhibition of MIF or its tautomerase activity ameliorates disease severity by reducing inflammatory responses. In this study, the human single-chain variable fragment (HuScFv) antibody specific to MIF was selected from the human antibody phage display library by using purified recombinant full-length human MIF (rMIF) as the target antigen. Monoclonal HuScFv was produced from phage-transformed bacteria and tested for their binding activities to rMIF by indirect enzyme-linked immunosorbent assay as well as to native MIF by western blot analysis and immunofluorescence assay. The HuScFv with highest binding signal to rMIF also inhibited the tautomerase activities of both rMIF and native MIF in human monoblastic leukemia (U937) cells in a dose-dependent manner. Mimotope searching and molecular docking concordantly demonstrated that the HuScFv interacted with Lys32 and Ile64 in the MIF tautomerase active site. To the best of our knowledge, this is the first study to focus on MIF-specific fully-human antibody fragment with a tautomerase-inhibitory effect that has potential to be developed as anti-inflammatory biomolecules for human use.


Subject(s)
Anti-Inflammatory Agents/administration & dosage , Immunity, Innate , Intramolecular Oxidoreductases/metabolism , Leukemia/drug therapy , Macrophage Migration-Inhibitory Factors/metabolism , Single-Chain Antibodies/administration & dosage , Catalytic Domain , Cell Line, Tumor , Enzyme-Linked Immunosorbent Assay , Humans , Intramolecular Oxidoreductases/antagonists & inhibitors , Intramolecular Oxidoreductases/immunology , Leukemia/immunology , Macrophage Migration-Inhibitory Factors/antagonists & inhibitors , Macrophage Migration-Inhibitory Factors/immunology , Protein Binding/immunology , Single-Chain Antibodies/metabolism
12.
Mol Biochem Parasitol ; 167(1): 60-71, 2009 Sep.
Article in English | MEDLINE | ID: mdl-19416741

ABSTRACT

In the present study we describe type 1 cystatin, a cysteine protease inhibitor, as a major released antigen of the tropical liver fluke Fasciola gigantica (FgStefin-1). Immunohistochemical analysis showed that FgStefin-1 is abundant in (a) tissue of tegumental type, including oral and ventral sucker, pharynx, genital atrium, metraterm, cirrus and (b) the intestinal epithelium. Faint staining was observed in the epithelia of ovary and proximal uterus. Immunoblots showed the presence of FgStefin-1 in the parasite's excretion/secretion (ES) product and immunodepletion demonstrated that FgStefin-1 herein is partially complexed with cathepsin L. Furthermore, quantitation of FgStefin-1 in comparison to cathepsin L in ES product and crude worm extract of adults supports a major external function of FgStefin-1 with an estimated 50% being released in at least equimolar amounts to cathepsin L. Sera of an experimentally infected rabbit reacted with recombinant FgStefin-1 starting 8 weeks postinfection. Activity analyses of recombinant FgStefin-1 showed nanomolar inhibition constants for mammalian cathepsin B, L, and S cysteine proteases and released cysteine proteases of the parasite. The protein is active over a wide pH range and is heat stable. Our results suggest protective functions of FgStefin-1, regulating intracellular cysteine protease activity, and possibly protection against extracellular proteolytic damage to the parasite's intestinal and tegumental surface proteins. Considering inhibition kinetics and previously demonstrated immunomodulatory properties of cystatin in parasitic nematodes a comparable function of FgStefin-1 is suggested and is at present under investigation.


Subject(s)
Cystatins/analysis , Cystatins/metabolism , Fasciola/chemistry , Fasciola/metabolism , Helminth Proteins/analysis , Helminth Proteins/metabolism , Amino Acid Sequence , Animal Structures/chemistry , Animals , Antibodies, Helminth/blood , Cathepsins/metabolism , Cystatins/genetics , Cysteine Endopeptidases/metabolism , DNA, Helminth/chemistry , DNA, Helminth/genetics , Helminth Proteins/genetics , Hydrogen-Ion Concentration , Lagomorpha/immunology , Lagomorpha/parasitology , Molecular Sequence Data , Protein Binding , Protein Stability , Sequence Analysis, DNA , Substrate Specificity , Temperature
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