Corrigendum: reduced IFNλ4 activity is associated with improved HCV clearance and reduced expression of interferon-stimulated genes

Erratum for Reduced IFNλ4 activity is associated with improved HCV clearance and reduced expression of interferon-stimulated genes. [Nat Commun. 2014]

Methodologies for the Analysis of HCV-Specific CD4(+) T Cells

Virus-specific CD4(+) T cells play a major role in viral infections, such as hepatitis C virus (HCV). Viral clearance is associated with vigorous and multi-specific CD4(+) T-cell responses, while chronic infection has been shown to be associated with weak or absent T-cell responses. Most of these studies have used functional assays to analyze virus-specific CD4(+) T-cell responses; however, these and other detection methods have various limitations. Therefore, the important question of whether virus-specific CD4(+) T cells are completely absent or primarily impaired in specific effector functions during chronic infection, has yet to be analyzed in detail. A novel assay, in which virus-specific CD4(+) T-cell frequencies can be determined by de novo CD154 (CD40 ligand) expression in response to viral antigens, can help to overcome some of the limitations of functional assays and restrictions of multimer-based methods. This and other current established methods for the detection of HCV-specific CD4(+) T cells will be discussed in this review.

Improvement of platelets after SVR among patients with chronic HCV infection and advanced hepatic fibrosis.

BACKGROUND & AIMS Patients with chronic hepatitis C virus (HCV) infection may develop cirrhosis with portal hypertension, reflected by decreased platelet count and splenomegaly. This retrospective cohort study aimed to assess changes in platelet counts after antiviral therapy among chronic HCV-infected patients with advanced fibrosis. METHODS Platelet counts and spleen sizes were recorded in an international cohort of patients with Ishak 4-6 fibrosis who started antiviral therapy between 1990 and 2003. Last measured platelet counts and spleen sizes were compared to their pre-treatment values (within 6 six months prior to the start of therapy). All registered platelet count measurements from 24 week following cessation of antiviral therapy were included in repeated measurement analyses. RESULTS This study included 464 patients; 353 (76%) had cirrhosis and 187 (40%) attained sustained virological response (SVR). Among patients with SVR, median platelet count, increased by 35 x10(9) /L (IQR 7-62, p<0.001). In comparison, patients without SVR showed a median decline of 17 x10(9) /L (IQR -5-47, p<0.001). In a subgroup of 209 patients, median decrease in spleen size was 1.0 cm (IQR 0.3-2.0) for patients with SVR, while median spleen size increased with 0.6 cm (IQR -0.1-2.0, p<0.001) among those without SVR. The changes in spleen size and platelet count were significantly correlated (R=-0.41, p<0.001). CONCLUSIONS Among chronic HCV-infected patients with advanced hepatic fibrosis the platelet counts improved following SVR and the change in platelets correlated with the change in spleen size following antiviral therapy. These results suggest that HCV eradication leads to reduced portal pressure. This article is protected by copyright. All rights reserved.

Modelling the impact of deferring HCV treatment on liver-related complications in HIV coinfected men who have sex with men

BACKGROUND AND AIMS Hepatitis C (HCV) is a leading cause of morbidity and mortality in people who live with HIV. In many countries, access to direct acting antiviral agents to treat HCV is restricted to individuals with advanced liver disease (METAVIR stage F3 or F4). Our goal was to estimate the long term impact of deferring HCV treatment for men who have sex with men (MSM) who are coinfected with HIV and often have multiple risk factors for liver disease progression. METHODS We developed an individual-based model of liver disease progression in HIV/HCV coinfected men who have sex with men. We estimated liver-related morbidity and mortality as well as the median time spent with replicating HCV infection when individuals were treated in liver fibrosis stages F0, F1, F2, F3 or F4 on the METAVIR scale. RESULTS The percentage of individuals who died of liver-related complications was 2% if treatment was initiated in F0 or F1. It increased to 3% if treatment was deferred until F2, 7% if it was deferred until F3 and 22% if deferred until F4. The median time individuals spent with replicating HCV increased from 5 years if treatment was initiated in F2 to almost 15 years if it was deferred until F4. CONCLUSIONS Deferring HCV therapy until advanced liver fibrosis is established could increase liver-related morbidity and mortality in HIV/HCV coinfected individuals, and substantially prolong the time individuals spend with replicating HCV infection.

Cloning of a protease gene family of Fasciola hepatica by the polymerase chain reaction

Degenerate oligonucleotide primers derived from conserved cysteine protease sequences were used in the reverse transcription polymerase chain reaction to amplify seven different cysteine protease cDNA clones, Fcp1-7, from RNA isolated from adult Fasciola hepatica. Five of the amplified F. hepatica sequences showed homology to the cathepsin L type and two were more related to the cathepsin B type. Southern blot analysis suggests that some members of this protease gene family are present in multiple copies. Northern blot analysis revealed differences in the levels of steady state mRNA expression for some of these proteases. The 5' and the 3' regions of Fcp1 were amplified using the rapid amplification of cDNA ends PCR protocol (RACE-PCR) and an additional clone was obtained by screening a lambda gt10 cDNA library using Fcp1 as a probe. The Fcp1 cDNA fragment was also subcloned in the expression vector pGEX and expressed as a glutathione-S-transferase (GST) fusion protein in Escherichia coli. Antibodies, raised in rabbits against the GST:Fcp1 fusion protein, were used in western blot analysis to examine expression in different life-cycle stages of F. hepatica. In extracts from adult and immature parasites, the immune serum recognised predominantly two proteins of 30 kDa and 38 kDa. In other parasite stages, proteins of different molecular weight were recognised by the anti-GST:Fcp1 antiserum, indicating stage-specific gene expression or processing of Fcp1. In gelatine substrate gel analysis, strong proteolytic activity could be detected at 30 kDa, but not at 38 kDa, suggesting that the 30 kDa protein represents the mature enzyme and the 38 kDa protein the proenzyme.

Non-sexual household transmission of HCV infection: A cohort study

Objective. This study was designed to determine the prevalence and incidence of HCV infection among non-sexual household contacts of HCV-infected women and to describe the association between HCV infection and potential household risk factors in order to examine whether non-sexual household contact is a route of transmission for HCV infection. ^ Methods. A baseline prevalence survey included 409 non-sexual household contacts of 241 HCV-infected index women in the Houston area from 1994 to 1997. A total of 470 non-sexual household contacts with no evidence of HCV infection at baseline investigation were re-assessed approximately three years after baseline enrollment. Information on potential risk factors was collected through face to face interviews and blood samples were tested for anti-HCV with ELISA-2 and Matrix/RIBA-2. The relationships between HCV infection and potential risk factors were examined by using univariate and multivariate logistic regression analyses. ^ Results. The overall prevalence of anti-HCV positivity among 409 non-sexual household contacts was 4.4%. The highest prevalence of anti-HCV was found in parents (19.5%), followed by siblings (8.1%) and other relatives (5.6%); the children had the lowest prevalence of anti-HCV (1.2%). The univariate analysis showed that IDU, blood transfusion, tattoos, sexual contact with injecting drug users, more than 3 sexual partners in a lifetime, history of a STD, incarceration, previous hepatitis, and contact with hepatitis patients were significantly associated with HCV infection, however, sharing razors, nail clippers, toothbrushes, gum, food or beds with HCV-infected women, and history of dialysis, health care job, body piercing, and homosexual activities were not. Multivariate analysis found that IDU (OR = 221.7 with 95% CI of 22.8 to 2155.7) and history of a STD (OR = 11.7 with 95% CI of 1.2 to 113.1) were the only variables significantly associated with HCV infection. No such associations remained for other risk factors. The three-year cumulative incidence of anti-HCV among 352 non-sexual household contacts of HCV-infected women was zero. ^ Conclusion. This study has provided no evidence that non-sexual household contact is a likely route of transmission for HCV infection. The risk of sharing razors, nail clippers, toothbrushes, gum, food and/or beds with HCV-infected women is not evident and has not been shown to be the likely mode for HCV spread among family members. This study does suggest that IDU is the likely route of transmission for most HCV infection. Association also has been shown independently with a history of STD. The prevalence of anti-HCV among non-sexual household contacts was low. Exposure to common parenteral risk factors and sexual transmission between sexual partners may account for HCV spread among household members of HCV-infected persons. ^

Protease-activated receptor-1 signaling plays a major role in melanoma growth and metastasis

Overexpression of the thrombin receptor (Protease-Activated-Receptor-1), PAR-1, in cell lines and tissue specimens correlates with the metastatic potential of human melanoma. Utilizing lentiviral shRNA to stably silence PAR-1 in metastatic melanoma cell lines results in decreased tumor growth and lung metastasis in vivo. Since the use of viral technology is not ideal for clinical therapies, neutral liposomes (DOPC) were utilized as a delivery vehicle for PAR-1 siRNA. Our data suggest that PAR-1 siRNA-DOPC treatment by systemic delivery significantly decreases tumor growth and lung metastasis in nude mice. Concomitant decreases in angiogenic and invasive factors (IL-8, VEGF, MMP-2) were observed in PAR-1 siRNA-DOPC-treated mice. Utilizing a cDNA microarray platform, several novel PAR-1 downstream target genes were identified, including Connexin 43 (Cx-43) and Maspin. Cx-43, known to be involved in tumor cell diapedesis and attachment to endothelial cells, is decreased after PAR-1 silencing. Furthermore, the Cx-43 promoter activity was significantly inhibited in PAR-1-silenced cells suggesting transcriptional regulation of Cx-43 by PAR-1. ChIP analysis revealed a reduction in SP-1 and AP-1 binding to the Cx-43 promoter. Moreover, melanoma cell attachment to HUVEC was significantly decreased in PAR-1-silenced cells as well as in Cx-43 shRNA transduced cells. As both SP-1 and AP-1 transcription factors act as positive regulators of Cx-43, our data provide a novel mechanism for the regulation of Cx-43 expression by PAR-1. Maspin, a serine protease inhibitor with tumor-suppressor function, was found to be upregulated after PAR-1 silencing. Our results indicate that PAR-1 transcriptionally regulates Maspin, as the promoter activity was significantly increased after PAR-1 silencing. ChIP analysis revealed that silencing PAR-1 increased binding of Ets and c-Jun to the Maspin promoter. As Maspin was recently found to be a tumor-suppressor in melanoma by reducing the invasive capacity of melanoma cells, invasion assays revealed a decrease in invasion after PAR-1 silencing and in cells transduced with a Maspin expression vector. We propose that PAR-1 is key to the progression and metastasis of melanoma in part by regulating the expression of Cx-43 and Maspin. Taken together, we propose that PAR-1 is an attractive target for the treatment of melanoma.^

Differential in vitro and in vivo effect of barley cysteine and serine protease inhibitors on phytopathogenic microorganisms

Protease inhibitors from plants have been involved in defence mechanisms against pests and pathogens. Phytocystatins and trypsin/α-amylase inhibitors are two of the best characterized protease inhibitor families in plants. In barley, thirteen cystatins (HvCPI-1 to 13) and the BTI-CMe trypsin inhibitor have been previously studied. Their capacity to inhibit pest digestive proteases, and the negative in vivo effect caused by plants expressing these inhibitors on pests support the defence function of these proteins. Barley cystatins are also able to inhibit in vitro fungal growth. However, the antifungal effect of these inhibitors in vivo had not been previously tested. Moreover, their in vitro and in vivo effect on plant pathogenous bacteria is still unknown. In order to obtain new insights on this feature, in vitro assays were made against different bacterial and fungal pathogens of plants using the trypsin inhibitor BTI-CMe and the thirteen barley cystatins. Most barley cystatins and the BTI-CMe inhibitor were able to inhibit mycelial growth but no bacterial growth. Transgenic Arabidopsis plants independently expressing the BTI-CMe inhibitor and the cystatin HvCPI-6 were tested against the same bacterial and fungal pathogens. Neither the HvCPI-6 expressing transgenic plants nor the BTI-CMe ones were more resistant to plant pathogen fungi and bacteria than control Arabidopsis plants. The differences observed between the in vitro and in planta assays against phytopathogenic fungi are discussed

A bacterial cysteine protease effector protein interferes with photosynthesis to suppress plant innate immune responses

The bacterial pathogen Pseudomonas syringae pv tomato DC3000 suppresses plant innate immunity with effector proteins injected by a type III secretion system (T3SS). The cysteine protease effector HopN1, which reduces the ability of DC3000 to elicit programmed cell death in non-host tobacco, was found to also suppress the production of defence-associated reactive oxygen species (ROS) and callose when delivered by Pseudomonas fluorescens heterologously expressing a P. syringae T3SS. Purified His 6 -tagged HopN1 was used to identify tomato PsbQ, a member of the oxygen evolving complex of photosystem II (PSII), as an interacting protein. HopN1 localized to chloroplasts and both degraded PsbQ and inhibited PSII activity in chloroplast preparations, whereas a HopN1 D299A non-catalytic mutant lost these abilities. Gene silencing of NtPsbQ in tobacco compromised ROS production and programmed cell death.

Identification of thaumatin-like protein and aspartyl protease as new major allergens in lettuce (Lactuca sativa)

Scope: Today, about 2–8% of the population of Western countries exhibits some type of food allergy whose impact ranges from localized symptoms confined to the oral mucosa to severe anaphylactic reactions. Consumed worldwide, lettuce is a Compositae family vegetable that can elicit allergic reactions. To date, however, only one lipid transfer protein has been described in allergic reaction to lettuce. The aim of this study was to identify potential new allergens involved in lettuce allergy. Methods and results: Sera from 42 Spanish lettuce-allergic patients were obtained from pa-tients recruited at the outpatient clinic. IgE-binding proteins were detected by SDS-PAGE and immunoblotting. Molecular characterization of IgE-binding bands was performed by MS. Thaumatin was purified using the Agilent 3100 OFFGEL system. The IgE-binding bands recognized in the sera of more than 50% of patients were identified as lipid transfer protein (9 kDa), a thaumatin-like protein (26 kDa), and an aspartyl protease (35 and 45 kDa). ELISA inhibition studies were performed to confirm the IgE reactivity of the purified allergen. Conclusion: Two new major lettuce allergens—a thaumatin-like protein and an aspartyl protease—have been identified and characterized. These allergens may be used to improve both diagnosis and treatment of lettuce-allergic patients.

The effect of a mono component protease and different AMEn levels in broiler diets on growth performance from 1 to 18 days of age.

The objective of the present study was to evaluate the effect of the inclusion of a mono component serine protease (RONOZYME ProAct, DSM Nutritional Products) in diets with two different AMEn contents on apparent ileal digestibility (AID) of amino acids (AA) and growth performance in broilers from 1 to 18 days of age.

The AtCathB3 gene, encoding a cathepsin B-like protease, is expressed during germination of Arabidopsis thaliana and transcriptionally repressed by the basic leucine zipper protein GBF1.

Protein hydrolysis plays an important role during seed germination and post-germination seedling establishment. In Arabidopsis thaliana, cathepsin B-like proteases are encoded by a gene family of three members, but only the AtCathB3 gene is highly induced upon seed germination and at the early post-germination stage. Seeds of a homozygous T-DNA insertion mutant in the AtCathB3 gene have, besides a reduced cathepsin B activity, a slower germination than the wild type. To explore the transcriptional regulation of this gene, we used a combined phylogenetic shadowing approach together with a yeast one-hybrid screening of an arrayed library of approximately 1200 transcription factor open reading frames from Arabidopsis thaliana. We identified a conserved CathB3-element in the promoters of orthologous CathB3 genes within the Brassicaceae species analysed, and, as its DNA-interacting protein, the G-Box Binding Factor1 (GBF1). Transient overexpression of GBF1 together with a PAtCathB3::uidA (β-glucuronidase) construct in tobacco plants revealed a negative effect of GBF1 on expression driven by the AtCathB3 promoter. In stable P35S::GBF1 lines, not only was the expression of the AtCathB3 gene drastically reduced, but a significant slower germination was also observed. In the homozygous knockout mutant for the GBF1 gene, the opposite effect was found. These data indicate that GBF1 is a transcriptional repressor of the AtCathB3 gene and affects the germination kinetics of Arabidopsis thaliana seeds. As AtCathB3 is also expressed during post-germination in the cotyledons, a role for the AtCathB3-like protease in reserve mobilization is also inferred.

C1A Cysteine protease-cystatin interactions in leaf senescence

Senescence-associated proteolysis in plants is a crucial process to relocalize nutrients from leaves to growing or storage tissues. The massive net degradation of proteins involves broad metabolic networks, different subcellular compartments, and several types of proteases and regulators. C1A cysteine proteases, grouped as cathepsin L-, B-, H-, and F-like according to their gene structures and phylogenetic relationships, are the most abundant enzymes responsible for the proteolytic activity during leaf senescence. Besides, cystatins as specific modulators of C1A peptidase activities exert a complex regulatory role in this physiological process. This overview article covers the most recent information on C1A proteases in leaf senescence in different plant species. Particularly, it is focussed on barley, as the unique species where the whole gene family members of C1A cysteine proteases and cystatins have been analysed.

Cloning and characterization of human protease-activated receptor 4

Protease-activated receptors 1–3 (PAR1, PAR2, and PAR3) are members of a unique G protein-coupled receptor family. They are characterized by a tethered peptide ligand at the extracellular amino terminus that is generated by minor proteolysis. A partial cDNA sequence of a fourth member of this family (PAR4) was identified in an expressed sequence tag database, and the full-length cDNA clone has been isolated from a lymphoma Daudi cell cDNA library. The ORF codes for a seven transmembrane domain protein of 385 amino acids with 33% amino acid sequence identity with PAR1, PAR2, and PAR3. A putative protease cleavage site (Arg-47/Gly-48) was identified within the extracellular amino terminus. COS cells transiently transfected with PAR4 resulted in the formation of intracellular inositol triphosphate when treated with either thrombin or trypsin. A PAR4 mutant in which the Arg-47 was replaced with Ala did not respond to thrombin or trypsin. A hexapeptide (GYPGQV) representing the newly exposed tethered ligand from the amino terminus of PAR4 after proteolysis by thrombin activated COS cells transfected with either wild-type or the mutant PAR4. Northern blot showed that PAR4 mRNA was expressed in a number of human tissues, with high levels being present in lung, pancreas, thyroid, testis, and small intestine. By fluorescence in situ hybridization, the human PAR4 gene was mapped to chromosome 19p12.