Project description:Hepatitis C virus (HCV) chronically infects 170 million people worldwide and is a leading cause of liver-related mortality due to hepatocellular carcinoma and cirrhosis1. Standard-of-care treatment is shifting from interferon-alpha (IFNM-NM-1)-based to IFNM-NM-1-free directly acting antiviral (DAA) regimens, which demonstrate improved efficacy and tolerability in clinical trials2,3. Virologic relapse after completion of DAA therapy is a common cause of treatment failure, although mechanisms are unclear2,3. We conducted a clinical trial using the DAA sofosbuvir with ribavirin (SOF/RBV)4, and report here detailed mRNA expression analysis of pre- and end-of-treatment (EOT) liver biopsies and blood samples. On-treatment viral clearance was accompanied by rapid down-regulation of interferon-stimulated genes (ISGs) in liver and blood. Analysis of paired liver biopsies from patients who achieved a sustained virologic response (SVR) revealed that viral clearance was accompanied by decreased expression of ISGs, IFNG, and IFNLs, but increased expression of IFNA2. Patients who achieved SVR had higher expression of a hepatic type-I interferon gene signature in unpaired EOT liver biopsies than patients who later relapsed. Together, these results support a model whereby restoration of type-I intrahepatic interferon signaling at the EOT is associated with sustained hepatic HCV suppression and prevention of relapse upon withdrawal of SOF/RBV. Sustained Virologic Response for Chronic Hepatitis C Patients Treated with Sofosbuvir and Ribavirin
Project description:Gene expression profiling of immortalized human mesenchymal stem cells with hTERT/E6/E7 transfected MSCs. hTERT may change gene expression in MSCs. Goal was to determine the gene expressions of immortalized MSCs.
Project description:Background: Hepatitis E Virus (HEV) is a new causative agent of chronic hepatitis in solid organ transplant recipients in Europe. Factors associated with the occurrence and persistence of chronic HEV infection remain largely unknown but chronic evolution seems to be the consequence of hostM-bM-^@M-^Ys immunological factors rather than of viral factors. Method: In a prospective case-control study, we have determined in whole blood of chronically HEV-infected kidney-transplant recipients the host response using microarray technology. Results: Chronically HEV-infected kidney-transplant recipients exhibited a specific transcriptional program, in which interferon effectors were prominent. The intensity of expression of each signatureM-bM-^@M-^Ys gene was significantly lower in patients who were subsequently cleared of HEV than in patients who were not. Furthermore, in patients who were cleared of HEV, a higher expression of these genes was associated with a longer delay until HEV clearance. Conclusions: The specific transcriptional program determined in chronically HEV-infected kidney-transplant recipients suggests an activation of type I interferon response. Intensity of interferon-stimulated genes expression could be useful to forecast the outcome of infection. High expression of interferon-stimulated genes could signify a dysregulation in the interferon response that might favour the persistence of the HEV infection. TrialM-bM-^@M-^Ys registration number: NCT01090232; RegistryM-bM-^@M-^Ys URL: http://clinicaltrials.gov/ct2/show/study/NCT01090232?term=kidney+transplant+recipients&cntry1=EU%3AFR&rank=2 Total RNA was extracted from whole-blood sample or monocytes of kidney-transplant patients with or without chronic hepatitis E (CHE) infection. Control patients were matched up with CHE patients for age, sex, time since kidney transplant and immunosuppressive treatment.
Project description:Kynureninase is a member of a large family of catalytically diverse but structurally homologous pyridoxal 5'-phosphate (PLP) dependent enzymes known as the aspartate aminotransferase superfamily or alpha-family. The Homo sapiens and other eukaryotic constitutive kynureninases preferentially catalyze the hydrolytic cleavage of 3-hydroxy-l-kynurenine to produce 3-hydroxyanthranilate and l-alanine, while l-kynurenine is the substrate of many prokaryotic inducible kynureninases. The human enzyme was cloned with an N-terminal hexahistidine tag, expressed, and purified from a bacterial expression system using Ni metal ion affinity chromatography. Kinetic characterization of the recombinant enzyme reveals classic Michaelis-Menten behavior, with a Km of 28.3 +/- 1.9 microM and a specific activity of 1.75 micromol min-1 mg-1 for 3-hydroxy-dl-kynurenine. Crystals of recombinant kynureninase that diffracted to 2.0 A were obtained, and the atomic structure of the PLP-bound holoenzyme was determined by molecular replacement using the Pseudomonas fluorescens kynureninase structure (PDB entry 1qz9) as the phasing model. A structural superposition with the P. fluorescens kynureninase revealed that these two structures resemble the "open" and "closed" conformations of aspartate aminotransferase. The comparison illustrates the dynamic nature of these proteins' small domains and reveals a role for Arg-434 similar to its role in other AAT alpha-family members. Docking of 3-hydroxy-l-kynurenine into the human kynureninase active site suggests that Asn-333 and His-102 are involved in substrate binding and molecular discrimination between inducible and constitutive kynureninase substrates.