The regulatory roles of Fasciola hepatica GSTO1 protein in inflammatory cytokine expression and apoptosis in murine macrophages

Fascioliasis, a global zoonotic parasitic disease, is mainly caused by Fasciola hepatica (F. hepatica) parasitizing in the livers of hosts, mainly humans and herbivores. Glutathione S-transferase (GST) is one of the important excretory- secretory products (ESPs) from F. hepatica, however, the regulatory roles of its Omega subtype in the immunomodulatory effects remain unknown. Here, we expressed F. hepatica recombinant GSTO1 protein (rGSTO1) in Pichia pastoris and analyzed its antioxidant properties. Then, the interaction between F. hepatica rGSTO1 and RAW264.7 macrophages and its effects on inflammatory responses and cell apoptosis were further explored. The results revealed that GSTO1 of F. hepatica owned the potent ability to resist oxidative stress. F. hepatica rGSTO1 could interact with RAW264.7 macrophages and inhibit its cell viability, furthermore, it may suppress the production of pro-inflammatory cytokines IL-1β, IL-6 and TNF-α, but promote the expression of anti-inflammatory cytokine IL-10. In addition, F. hepatica rGSTO1 may down-regulate the ratio of Bcl-2/Bax, and increase the expression of pro-apoptotic protein caspase-3, thereby eliciting the apoptosis of macrophages. Notably, F. hepatica rGSTO1 inhibited the activation of nuclear factor-κB (NF-κB) and mitogen‑activated protein kinases (MAPKs p38, ERK and JNK) pathways in LPS-activated RAW264.7 cells, exerting potent modulatory effects on macrophages. These findings suggested that F. hepatica GSTO1 can modulate the host immune response, which provided new insights into the immune evasion mechanism of F. hepatica infection in host.

Transcriptome changes in chlorsulfuron-treated plants are caused by acetolactate synthase inhibition and not induction of a herbicide detoxification system in Marchantia polymorpha

A sensing mechanism in mammals perceives xenobiotics and induces the transcription of genes encoding proteins that detoxify these molecules. However, it is unclear if plants sense xenobiotics, and activate an analogous signalling system leading to their detoxification. Using the liverwort Marchantia polymorpha, we tested the hypothesis that there is a sensing system in plants that perceives herbicides resulting in the increased transcription of genes encoding proteins that detoxify these herbicides. Consistent with the hypothesis, we show that chlorsulfuron-treatment induces changes in the M. polymorpha transcriptome. However, these transcriptome changes do not occur in chlorsulfuron (CS)-treated target site resistant mutants, where the gene encoding the target carries a mutation that confers resistance to chlorsulfuron. Instead, we show that inactivation of the chlorsulfuron target, acetolactate synthase (ALS) (also known as acetohydroxyacid synthase (AHAS)), is required for the transcriptome response. These data demonstrate that the transcriptome changes in chlorsulfuron-treated plants are caused by disrupted amino acid synthesis and metabolism resulting from acetolactate synthase inhibition, and indicate that the transcriptome changes are not caused by a herbicide sensing mechanism.

Partial Purification of Glutathione S-transferase Enzyme From the Seed of Mallow (Malva Slyvestris L.) and Investigation of the Inhibition Kinetics of Some Heavy Metals

Glutathione S-Transferase (GST) enzyme is abundant in mammals, insects, fish and microorganisms, as well as in various tissues of these species, particularly in tissues exposed to xenobiotics from the environment. As a result, the enzyme execute detoxifying function by scavenging a diverse range of xenobiotics, such as chemotherapeutic medicines, environmental carcinogens and endogenous compounds. In this study, GST enzyme was partially purified from mallow (Malva slyvestris L.) seed for the first time and the kinetic parameters were determined. The optimum ionic intensity was found in 400 mM Tris-Buffer, optimum pH: 7.0, and optimum substrate concentration was determined as 0.2 mM. One of the biggest reasons for deterioration of ecological balance in nature is heavy metal accumulation in soil, air and water which becomes a major threat to the vital activities of living things. In this study, inhibitory effects of Cd^+ 2, Ag⁺, Zn^+ 2 and Fe^+ 3 heavy metals, which are common in nature, on mallow seed glutathione S-transferase enzyme were investigated. Each heavy metal showed micromolar inhibitory effects on enzyme activity. IC₅₀ values of the metals were calculated as 60.93, 74.602, 178.22 and 369 µM, respectively.

Reduction of multiple antibiotics from the waste water using coated glutathione S-transferase producing biocatalyst

Oxytetracycline is widely used in veterinary and human medicine. It has been detected in wastewater from pharmaceuticals, hospitals and domestic wastewater. In recent years, much more attention has been directed towards glutathione transferases (GSTs) because of their bio-transforming ability of antibiotics. In this study, 19 Lactobacillus strains were initially screened for the production of GSTs and five strains were selected for biotransformation of oxytetracycline. Among the strains, L. fermentum LA6 improved oxytetracyline degradation than other strains. It was subjected to optimize GST production and optimum growth was achieved after 24 h incubation at 32 ± 2 °C and 200 mg/L initial oxytetracycline concentration. The biocatalyst was immobilized and antibiotic degradation efficiency was analyzed. The immobilized culture of L. fermentum LA6 improved biodegradation of oxytetracycline in the wastewater. At 50 mg/L initial antibiotic concentration, 53.2 ± 2.8% oxytetracycline degradation was achieved, however, it improved at 200 mg/L antibiotic concentration in the culture medium (89.1 ± 4.3%) after 24 h. The chemical oxygen demand (COD) of the wastewater decreased significantly after treatment. At 200 mg/L oxytetracycline concentration, COD removal was considerably high (93.6 ± 5.3 mg/L) than 150 mg/L oxytetracycline concentration in the medium. Antibiotic removal efficiency in immobilized form revealed that this method is highly suitable for the removal of antibiotics from the wastewater.

Impact of glutathione S transferases P1 (Ile105Val) variants on the risk of GSTp, phosphorylated c-Jun kinase, and P53 phenotypic expression and their implications on overall survival outcomes in non-small cell lung cancer patients treated with chemotherapy

AIM

This study focused on GST-M1, T1 null, and P1 Ile105Val variant genotypes associated with the risk of altered expression of GSTp, pJNK, and P53 in NSCLC patients. These markers and overall survival (OS) were correlated with a key set of clinicopathological characteristics.

METHODS

Genotyping of GST- M1, T1 (+/-), and P1 (Ile105Val) was performed using PCR-RFLP.The expression of GSTp, pJNK, and P53 phenotypes was assessed by immunohistochemistry. The Spearman test was used to examine the correlation between GSTp, pJNK, and P53. Kaplan-Meier test was used for OS analysis.

RESULTS

GSTP1 Val/Val and Ile/Val genotypes notably increased GSTp expression by 1.8 and 1.7 fold, respectively (p = 0.04,p = 0.06). GSTP1 Val/Val and Ile/Val genotypes considerably reduced P53 expression by 0.61 and 0.57 fold, respectively (p = 0.03& p = 0.05), respectively. GSTp, pJNK, and P53 were significantly co-expressed (p < 0.001). GSTp and pJNK expression showed a moderate negative correlation (ρ = -0.32, p = 0.046). In contrast, GSTp and P53 expression exhibited a strong negative correlation (ρ = -0.53, p < 0.0001). There was no correlation between P53 and pJNK expression(ρ = 0.07, p = 0.54). The patient's median OS was 8.9 months, and it was significantly related to pack-years, stage, metastasis, and GSTM1(-/-) genotypes (p > 0.05). SQCLC showed poor OS than ADC (5.7 months vs.9.1 months, p = 0.2). Stage IV and metastasis significantly reduced the OS (p = 0.001). The tumour size and lymph nodes reflected poor OS (p = 0.07&p = 0.06). Gemcitabine+Cisplatin and Gefitinib showed a slightly higher rate of survival (9.3 months and 8.1 months) than Pemtrexe+Cisplatin treatment (7.0 months,p = 0.8). Multivariate analysis revealed that pack-years and GSTp were independent predictors for OS (p = 0.03).

CONCLUSION

GSTp, pJNK, and P53 showed interconnected cascading. Age, pack-year, stage, and GSTp were found to be significant predictive factors for OS.Pack-years, GSTp independent OS predictor.

Antibiotics as Inhibitor of Glutathione S-transferase: Biological Evaluation and Molecular Structure Studies

BACKGROUND

The glutathione S-transferases (GSTs) are family of enzymes that are notable for their role in phase II detoxification reactions. Antibiotics have been reported to have several adverse effects on the activity of the enzymes in mammals.

AIM

The aim of this study was the structural and biochemical characterization of rat erythrocyte GST and understanding the effects of gentamicin, clindamycin, cefazolin, ampicillin and scopolamine butylbromide on the activity of human erythrocyte GST using rat as a model.

METHODS

The enzyme was purified by GSH-agarose affinity chromatography. In vitro GST enzyme activity was measured at 25°C using CDNB as a model substrate. IC50 of drugs was measured by activity % vs compound concentration graphs. Lineweaver Burk graphs were drawn to determine the inhibition type and Ki constants for the drugs. The structure of the enzyme was predicted via Protein Homology/analogy Recognition Engine.

RESULTS

In this study, GST was purified from rat erythrocyte with a specific activity of 6.3 EU/mg protein, 44 % yield and 115 fold. Gentamicin and clindamycin inhibited the enzymatic activity with IC50 of 1.69 and 6.9 mM and Ki of 1.70 and 2.36 mM, respectively. Ampicillin and scopolamine butylbromide were activators of the enzyme, while the activity of the enzyme was insensitive to cefazolin. The enzyme was further characterized by homology modeling and sequence alignment revealing similarities with human GST.

CONCLUSION

Collectively, it could be concluded that gentamicin and clindamycin are the inhibitors of erythrocyte GST.

CYP2E1, GSTM1, and GSTT1 genetic polymorphisms and their associations with susceptibility to antituberculosis drug-induced liver injury in Thai tuberculosis patients

Antituberculosis drug-induced liver injury (ATDILI) is the common adverse reaction of antituberculosis drugs. Glutathione S-transferases (GSTs), which are phase II metabolizing enzymes for detoxification, are recognized as potential mediators of hepatotoxicity. However, role of GSTs polymorphisms in ATDILI pathogenesis has never been observed in Thais. This study aimed to investigate associations between GSTs and ATDILI susceptibility. This retrospective case-control multicentered study was conducted by the collaboration from ten secondary and tertiary care hospitals across Thailand, including Northern, Central, and Southern parts of Thailand. We enrolled 80 tuberculosis (TB) patients with ATDILI and 174 those without ATDILI into the study. Polymerase chain reaction (PCR) was used to determine genetic polymorphisms of GSTM1 and GSTT1 genes. CYP2E1 genotyping data were derived from microarray data. We illustrated that GSTT1 null and GSTM1/GSTT1 dual null genotypes were correlated with an increased risk of ATDILI with odds ratio (OR) at 1.83 (95% confidence interval (CI), 1.00 to 3.35; P = 0.049) and 2.12 (95%CI, 1.02 to 4.38; P = 0.044), respectively. Interestingly, GSTT1 null and GSTM1/GSTT1 dual null genotypes were found to be correlated with an increased risk of ATDILI in Thai TB patients who carried CYP2E1 wild type phenotype with OR 2.99 (95%CI, 1.07 to 8.39; P = 0.037) and 3.44 (95%CI, 1.01 to 11.71; P = 0.048), respectively. Collectively, GSTT1 null and GSTM1/GSTT1 dual null genotypes were associated with a higher risk of ATDILI in Thai TB patients, which may serve as alternative genetic biomarkers for ATDILI.

A cisplatin-based platinum(IV) prodrug containing a glutathione s-transferase inhibitor to reverse cisplatin-resistance in non-small cell lung cancer

A Pt(IV) prodrug of cisplatin containing a glutathione s-transferase (GSTs) inhibitor 6-(7-nitro-2,1,3-benzoxadiazol-4-ylthio)hexanol (NBDHEX), complex 1, was designed and studied aiming to overcome cisplatin-resistance and reduce its toxicity by inhibiting GSTs overexpressed in cancer cells. The complex could be reduced to release its active Pt(II) species and axial ligand in the presence of ascorbic acid. In cytotoxicity study, complex 1 showed more potent anticancer activity than cisplatin and NBDHEX against all the tested cancer cells, especially toward cisplatin resistant A549/DDP cells with a resistance factor value of 0.37. By effectively inhibiting GSTs, complex 1 was found to be able to promote higher platinum uptake and cause more severe DNA damage in both A549 cells and A549/DDP cells as compared with cisplatin. Further mechanism study indicated that it could trigger cell death via an apoptotic pathway. In vivo tests on A549 xenograft tumor mice model showed that complex 1 presented higher tumor inhibiting rate and lower toxicity than cisplatin as well. In all, the Pt(IV) prodrug has potential to be developed as an anticancer agent.

Rhodnius prolixus supergene families of enzymes potentially associated with insecticide resistance

Chagas disease or American trypanosomiasis, is a potentially life-threatening illness caused by the protozoan parasite, Trypanosoma cruzi. Once known as an endemic health problem of poor rural populations in Latin American countries, it has now spread worldwide. The parasite is transmitted by triatomine bugs, of which Rhodnius prolixus (Hemiptera, Reduviidae, Triatominae) is one of the vectors and a model organism. This species occurs mainly in Central and South American countries where the disease is endemic. Disease prevention focuses on vector control programs that, in general, rely intensely on insecticide use. However, the massive use of chemical insecticides can lead to resistance. One of the major mechanisms is known as metabolic resistance that is associated with an increase in the expression or activity of detoxification genes. Three of the enzyme families that are involved in this process - carboxylesterases (CCE), glutathione s-transferases (GST) and cytochrome P450s (CYP) - are analyzed in the R. prolixus genome. A similar set of detoxification genes to those of the Hemipteran Acyrthosiphon pisum but smaller than in most dipteran species was found in R. prolixus genome. All major CCE classes (43 genes found) are present but the pheromone/hormone processing class had fewer genes than usual. One main expansion was detected on the detoxification/dietary class. The phosphotriesterase family, recently associated with insecticide resistance, was also represented with one gene. One microsomal GST gene was found and the cytosolic GST gene count (14 genes) is extremely low when compared to the other hemipteran species with sequenced genomes. However, this is similar to Apis mellifera, a species known for its deficit in detoxification genes. In R. prolixus 88 CYP genes were found, with representatives in the four clans (CYP2, CYP3, CYP4 and mitochondrial) usually found in insects. R. prolixus seems to have smaller species-specific expansions of CYP genes than mosquitoes and beetles, among others. The number of R. prolixus CYP genes is similar to the hemipteran Ac. pisum, although with a bigger expansion in CYP3 and CYP4 clans, along with several gene fragments, mostly in CYP4 clan. Eleven founding members of new families were detected, consisting of ten genes in the CYP3 clan and 1 gene in the CYP4 clan. Members of these clans were proposed to have important detoxification roles in insects. The identification of CCE, GST and CYP genes is of utmost importance for directing detoxification studies on triatomines that can help insecticide management strategies in control programs.

Infection of Schistosomiasis japanicum is likely to enhance proliferation and migration of human breast cancer cells: mechanism of action of differential expression of MMP2 and MMP9

OBJECTIVE

To study whether the infection of Schistosomiasis japanicum (S. japanicum) is related to enhanced proliferation and migration of cancer cells, and the molecular mechanism pertains to cancer cell metastasis in human host.

METHODS

The gene of S. japanicum glutathione transferase (sjGST) cloned from S. japanicum was expressed, purified and applied in a series of assays to explore the effect of sjGST on proliferation and migration of MDA-MB-435S, and the expression of MMP2 and MMP9. Immunofluorescence assay for the binding of sjGST to MDA-MB-435S was also carried out.

RESULTS

Results showed that sjGST enhanced proliferation and migration in human breast cancer cell MDA-MB-435S signifycantly at 50-200 nM, but did not enhance them in human lung cancer cell A549. Immunofluorescence assay for the binding of sjGST to MDA-MB-435S and A549 showed that GST was readily bound to the breast cancer cells, but showed almost no binding to human lung cancer cells. The assays for gelatinase activity showed that both MMP2 and MMP9 activities were increased significantly in the presence of sjGST (50-200 nM) in MDA-MB-435S, but they were not significant in A549.

CONCLUSIONS

Our current results show strongly that S. japanicum GST binds to MDA-MB-435S probably via its receptor, and enhances proliferation and migration of the cancer cells by up-regulatory expression of MMP2 and MMP9.

Proteolytically activated anti-bacterial hydrogel microspheres

Hydrogels are finding increased clinical utility as advances continue to exploit their favorable material properties. Hydrogels can be adapted for many applications, including surface coatings and drug delivery. Anti-infectious surfaces and delivery systems that actively destroy invading organisms are alternative ways to exploit the favorable material properties offered by hydrogels. Sterilization techniques are commonly employed to ensure the materials are non-infectious upon placement, but sterilization is not absolute and infections are still expected. Natural, anti-bacterial proteins have been discovered which have the potential to act as anti-infectious agents; however, the proteins are toxic and need localized release to have therapeutic efficacy without toxicity. In these studies, we explore the use of the glutathione s-transferase (GST) to anchor the bactericidal peptide, melittin, to the surface of poly(ethylene glycol) diacrylate (PEGDA) hydrogel microspheres. We show that therapeutic levels of protein can be anchored to the surface of the microspheres using the GST anchor. We compared the therapeutic efficacy of recombinant melittin released from PEGDA microspheres to melittin. We found that, when released by an activating enzyme, thrombin, recombinant melittin efficiently inhibits growth of the pathogenic bacterium Streptococcus pyogenes as effectively as melittin created by solid phase peptide synthesis. We conclude that a GST protein anchor can be used to immobilize functional protein to PEGDA microspheres and the protein will remain immobilized under physiological conditions until the protein is enzymatically released.