Expression of TRIM22 mRNA in chronic hepatitis C patients treated with direct-acting antiviral drugs

Hepatitis C is a global public health problem, and Pakistan is the second largest country in the globe with highest prevalence rate of hepatitis C virus (HCV). Until 2014, pegylated interferon (PEG-IFN) plus ribavirin (RBV) has been the standard therapy for HCV, however, owing to its adverse side effects and very low sustained virologic response (SVR) rates therapeutics trend is shifted toward direct-acting antivirals. Tripartite motif containing 22 (TRIM22) is a dynamic antiviral protein that can inhibit multiple viruses in vivo. Expression of TRIM22 mRNA has been linked to outcome of PEG-IFN and ribavirin therapy, where its higher expression leads to rapid virus clearance. However, in terms of therapy with direct-acting antiviral (DAA) or double DAA, impact of TRIM22 expression is largely unknown. These new drugs show more than 90% of SVR rates and lesser side effects and have proven to be better than IFN therapy. Endogenous IFN system suppresses various pathogens through the induction of antiviral effectors termed as interferon-stimulating genes (ISGs). We have studied the expression levels of one of these antiviral effectors, TRIM22 in response to sofosbuvir (SOF) and daclatasvir (DAC) in combination with RBV, using quantitative PCR in the peripheral blood mononuclear cells (PBMCs) of HCV-infected patients. We have observed sustained virus clearance in more than 90% of patients treated with DAA and double DAA and have seen the expression of TRIM22 to be higher in patients who attained SVR as compared to the untreated patients. We have also observed downregulation of TRIM22 in patients who failed to attain rapid virus clearance, and upregulation in those who achieved rapid clearance of virus. Genetic factors that determine the lower TRIM22 expression in these patients are needed to be explored that may also play a role in lower response to anti-HCV therapy. Endogenous IFN system and effects of antiviral proteins in response to DAA therapy is needed to be studied in order to better understand the host response toward these drugs to make them more effective.     

Coxsackievirus B3 replication and persistence in intestinal cells from mice infected orally and in the human CaCo-2 cell line

Although the transmission of coxsackievirus B3 occurs mainly via the oral route, little is known about the primary replication and persistence of this agent in the intestine. To address this question, BALB/c mice were inoculated by gavage with coxsackievirus B3, Nancy strain. The mice were killed from 1 hr to 90 days after infection. The viral markers were detected in the small intestine using RT-PCR, cell culture and detection of VP1 protein. Coxsackievirus B3 was detected positive by the three methods from hr 2 to day 45 after infection. By using monoclonal antibodies directed towards VP1, CD40 and CD26, the virus was shown to be present in the lymphocytes of the mucosa as soon as 2 hr after infection; in contrast, no virus was detected in the epithelial cells lining the intestinal lumen. Further experiments were performed to evaluate the capacity of coxsackievirus B3 to establish a persistent infection in two intestinal cell lines. In contrast to HT29 cells, the CaCo-2 cells were shown to develop a persistent infection for up to 20 passages, as demonstrated by the detection of viral RNA and VP1 protein. This study provides further evidence that, after infection by the oral route, the viral particles are concentrated in the lymphocytes of the mucosal layer. In addition, the results suggest that coxsackievirus B3 is capable of establishing a persistent infection in the small intestine that may act as a reservoir of viral particles for the delayed spread of the virus to other target organs.     

Respiratory syncytial virus associated illness in high-risk children and national characterisation of the circulating virus genotype in South Africa.

BACKGROUND: There is limited information about respiratory syncytial virus (RSV) in high-risk children from developing countries or on the genotype characterisation of the circulating virus. OBJECTIVE: To define the proportion of children with RSV associated lower respiratory tract infections (LRTI) that had risk factors for severe disease and to genotype the circulating RSV strains across the country. STUDY DESIGN: A prospective study was performed in four distinct regions. During April 2000-December 2000 (period 1), all children, with LRTI or without underlying high risk factors for severe RSV disease were enrolled. During January to September 2001 (period 2), only children with LRTI with underlying high risk factors were enrolled. Nasopharyngeal aspirates were evaluated for RSV infection using an ELISA test. RSV isolates were also subtyped and genotyped. RESULTS: Fifty three (24%) of 220 children enrolled during period 1 had risk factors for severe RSV disease; in addition to which a further 38 high-risk children were enrolled during 2001. RSV was isolated from 16 (30%) of 53 and 37 (22%) of 167 high-risk and non-high risk children, respectively, P=0.31. High-risk children were more likely to require intensive unit care (25 vs. 2.7%, P=0.02) and were also more likely to be hospitalised for a longer duration (median 7 vs. 5 days, P=0.06) than non high-risk infants. Overall (periods 1 and 2), RSV was isolated from 34 (37.4%) of the 91 high-risk infants enrolled. Among high-risk children, those from whom RSV was isolated were more likely to require hospitalisation (73.5 vs. 54.4%, P=0.07) and admission to an intensive care unit (14.7 vs. 1.8%, P=0.03) than those from whom RSV was not isolated. Of 40 isolates subtyped during period one, 92.5% were subtype A. Further, 27 (83.3%) of 30 subtype A isolates genotyped during period 1 clustered with GA2. CONCLUSION: RSV is an important cause of LRTI among high-risk infants in a developing country such as South Africa. For the season in question, the genotype that was dominant in Johannesburg was isolated throughout the country, suggesting that successful genotypes may have the ability to spread nationwide.     

An investigation of human and rat liver microsomal mycophenolic acid glucuronidation: evidence for a principal role of UGT1A enzymes and species differences in UGT1A specificity.

Mycophenolic acid (MPA; 1,3-dihydro-4-hydroxy-6-methoxy-7-methyl-3-oxo-5-isobenzylfuranyl)-4-methyl-4-hexenoate), the active metabolite of the immunosuppressant prodrug, mycophenolate mofetil, undergoes glucuronidation to its 7-O-glucuronide as a primary route of metabolism. Because differences in glucuronidation may influence the efficacy and/or toxicity of MPA, we investigated the MPA UDP-glucuronosyltransferase (UGT) activities of human liver microsomes (HLMs) and rat liver microsomes with the goal of identifying UGTs responsible for MPA catalysis. HLMs (n = 23) exhibited higher average MPA glucuronidation rates (14.7 versus 6.0 nmol/mg/min, respectively, p < 0.001) and higher apparent affinity for MPA (K(m) = 0.082 mM versus 0.20 mM, p < 0.001) compared with rat liver microsomes. MPA UGT activities were reduced >80% in liver microsomes from Gunn rats. To identify the active enzymes, human and rat UGT1A enzymes were screened for MPA-glucuronidating activity. UGT1A9 was the only human liver-expressed UGT1A enzyme with significant activity and exhibited both high affinity (K(m) = 0.077 mM) and high activity (V(max) = 28 nmol x min(-1) x mg(-1)). Spearman correlation analyses revealed a stronger relationship between HLM MPA UGT activities and 1A9-like content (r(2) = 0.79) relative to 1A1 (r(2) = 0.20), 1A4-like (r(2) = 0.22), and 1A6 (r(2) = 0.41) protein. A different profile was observed for rat with three active liver-expressed UGT1A enzymes: 1A1 (medium affinity/capacity), 1A6 (low affinity/medium capacity), and 1A7 (high affinity/capacity). Our data suggest that UGT1A enzymes are the major contributors to hepatic MPA metabolism in both species, but 1A9 is dominant in human, whereas 1A1 and 1A7 are likely the principal mediators in control rat liver. This information should be useful for interpretation of MPA pharmacokinetic and toxicity data in clinical and animal studies.     

Corticosteroid treatment exacerbates nephrotic syndrome in a zebrafish model of magi2a knockout

1. Download high-res image (304KB)
2. Download full-size image

     

HLA incompatible combined liver–kidney transplantation: Dynamics of antibody modulation revealed by a novel approach to HLA antibody characterisation

This case report confirms the utility of simultaneous liver transplantation in allowing successful kidney transplantation in the face of preformed, high levels of DSA, which would under normal circumstances be associated with hyperacute rejection and kidney graft failure. Antibody characterisation in terms of epitope specificity is more accurate and informative than antibodies described as “antigen-specific” and we suggest a method for identifying and tracking these antibodies; i.e. follow the epitope reaction not the antigen reactions. We consider that this will give a better insight into the behaviour and pathogenicity of HLA-specific sera. In the case presented here this approach has revealed some novel features of the post transplant antibody response in a sensitised recipient. These illustrate three phenomena which challenge current dogmas; an early resynthesis of DSA does not necessarily cause AMR, high levels of DSA can spontaneously modulate, and measurement of antibodies in terms of antigen specificity can give misleading results.