Identification and characterization of Sofosbuvir-resistant mutations of hepatitis C virus genotype 3a replicon.

Hepatitis C virus (HCV) infection is a major cause of chronic liver disease worldwide. Among its 8 genotypes (GT), GT3 has a relatively lower sustained virological response to highly effective direct-acting antiviral agents (DAA). Sofosbuvir (SOF), an anti-NS5B polymerase inhibitor, is a core component of many anti-HCV DAA cocktail regimens, and its resistant mutations are rare in clinics because these mutations usually severely impair the NS5B polymerase activity, including a mutation S282T in NS5B, the most frequently reported SOF-resistant mutation. In this study, we selected SOF-resistant variants of a previously developed GT3 subgenomic replicon (PR87A7). Two mutations were identified in the viral genome of SOF-resistant PR87A7 variants, Q606R in nontargeted NS3 and S282T in targeted N5SB. We demonstrated that Q606R could rescue the replication defect of S282T in PR87A7, and the resulting double mutant confers the SOF resistance. Finally, we showed that NS3-606R could not compensate for the replication defect of S282T in other GTs. In conclusion, we identified a novel GT3-specific combination of two mutations that confers SOF resistance. Our result calls for attention to potential mutations that may arise in nontargeted viral proteins during the SOF-based DAA treatment of chronic HCV.

Hepatitis C virus genotype 4: A poorly characterized endemic genotype.

Globally, 13% of all hepatitis C virus (HCV) infections are caused by genotype 4 (GT4), which consists of 17 subtypes with various levels of susceptibility to anti-HCV therapy. This genotype is endemic in the Middle East and Africa and has considerably spread to Europe lately. The molecular features of HCV-GT4 infection, as well as its appropriate therapeutics, are poorly characterized as it has not been the subject of widespread basic research. As such, in this review, we aim to gather the current state of knowledge of this genotype with a particular emphasis on its heterogeneity, sequence signatures, resistance-associated substitutions, and available in vivo and in vitro models used for its study. We urge developing more cell-culture models based on different GT4 subtypes to better understand the virology and therapeutic response of this particular genotype. This review may raise more awareness about this genotype and trigger more basic research work to develop its research tools. This will be critical to design better therapeutics and help to provide adequate guidelines for physicians working with HCV-GT4 patients.

Global Burden of Hepatitis B Infection in People Living With Human Immunodeficiency Virus: A Systematic Review and Meta-analysis.

BACKGROUND: This meta-analysis was conducted to estimate the global burden of hepatitis B virus (HBV) infection in people living with human immunodeficiency virus (PLWH). METHODS: We searched multiple databases for studies published between January 1990 and December 2017. HBV infection (hepatitis B surface antigen) was diagnosed with serological assays. A random-effects meta-analysis served to pool data. RESULTS: We included 358 studies (834 544 PLWH from 87 countries). The pooled prevalence of HBV infection was 8.4% (95% confidence interval [CI], 7.9%-8.8%), among which 26.8% (95% CI, 22.0%-31.9%) was positive to hepatitis B e antigen. HBV prevalence (with 95% CIs) differed according to region: West and Central Africa, 12.4% (11.0%-13.8%); Middle East and North Africa, 9.9% (6.0%-14.6%); Asia and the Pacific, 9.8% (8.7%-11.0%); Eastern and Southern Africa, 7.4% (6.4%-8.4%); Western and Central Europe and North America, 6.0% (5.5%-6.7%); and Latin America and the Caribbean, 5.1% (4.2%-6.2%) (P < .0001). The prevalence decreased from 10.4% in low-developed to 6.6% in highly developed countries (P < .0001) and increased from 7.3% in countries with HIV prevalence ≤1% to 9.7% in countries with HIV prevalence >1% (P < .0001). Globally, we estimated that there were 3 136 500 (95% CI, 2 952 000-3 284 100) cases of HBV in PLWH, with 73.8% of estimated regional cases from sub-Saharan Africa and 17.1% from Asia and the Pacific. CONCLUSIONS: This study suggests a high burden of HBV infection in PLWH, with disparities according to region, level of development, and country HIV prevalence.

Insulin resistance and associated factors among HIV-infected patients in sub-Saharan Africa: a cross sectional study from Cameroon.

BACKGROUND: Little is known on the magnitude and correlates of insulin resistance in HIV-infected people in Africa. We determined the prevalence of insulin resistance and investigated associated factors in HIV-infected adult Cameroonians. METHODS: We conducted a cross-sectional study at the Yaoundé Central Hospital, Cameroon; during which we enrolled HIV-infected people aged 30 to 74 years with no previous history of cardiovascular disease. An homeostatic model assessment of insulin resistance (HOMA-IR) like index served to assess insulin sensitivity with insulin resistance defined by values of 2.1 or higher. RESULTS: We included 452 patients (20% men). Their mean age was 44.4 ± 9.8 years and 88.5% of them were on antiretroviral therapy (93.3% on first line regimen including Zidovudine, lamivudine and Efavirenz/Nevirapine). Of all participants, 28.5% were overweight, 19.5% had obesity and 2.0% had diabetes. The prevalence of insulin resistance was 47.3% without any difference between patients on ART and those ART-naïve (48.5% vs. 38.5%; p = 0.480). Obesity was the only factor independently associated with insulin resistance (adjusted odds ratio: 2.28; 95% confidence interval: 1.10-4.72). CONCLUSION: Insulin resistance is present in nearly half of HIV-infected patients in Cameroon despite a low prevalence rate of diabetes, and is associated with obesity.

Gasdermin D promotes influenza virus-induced mortality through neutrophil amplification of inflammation.

Influenza virus activates cellular inflammasome pathways, which can be both beneficial and detrimental to infection outcomes. Here, we investigate the function of the inflammasome-activated, pore-forming protein gasdermin D (GSDMD) during infection. Ablation of GSDMD in knockout (KO) mice (Gsdmd-/-) significantly attenuates influenza virus-induced weight loss, lung dysfunction, lung histopathology, and mortality compared with wild type (WT) mice, despite similar viral loads. Infected Gsdmd-/- mice exhibit decreased inflammatory gene signatures shown by lung transcriptomics. Among these, diminished neutrophil gene activation signatures are corroborated by decreased detection of neutrophil elastase and myeloperoxidase in KO mouse lungs. Indeed, directly infected neutrophils are observed in vivo and infection of neutrophils in vitro induces release of DNA and tissue-damaging enzymes that is largely dependent on GSDMD. Neutrophil depletion in infected WT mice recapitulates the reductions in mortality, lung inflammation, and lung dysfunction observed in Gsdmd-/- animals, while depletion does not have additive protective effects in Gsdmd-/- mice. These findings implicate a function for GSDMD in promoting lung neutrophil responses that amplify influenza virus-induced inflammation and pathogenesis. Targeting the GSDMD/neutrophil axis may provide a therapeutic avenue for treating severe influenza.

Identification of a novel replication-competent hepatitis C virus variant that confers the sofosbuvir resistance.

Despite the excellent antiviral potency of direct-acting antivirals (DAAs) against hepatitis C virus (HCV), emergence of drug-resistant viral mutations remains a potential challenge. Sofobuvir (SOF), a nucleotide analog targeting HCV NS5B - RNA-dependent RNA polymerase (RdRp), constitutes a key component of many anti-HCV cocktail regimens and confers a high barrier for developing drug resistance. The serine to threonine mutation at the amino acid position 282 of NS5B (S282T) is the mostly documented SOF resistance-associated substitution (RAS), but severely hampers the virus fitness. In this study, we first developed new genotype 1b (GT1b) subgenomic replicon cells, denoted PR52D4 and PR52D9, directly from a GT1b clinical isolate. Next, we obtained SOF-resistant and replication-competent PR52D4 replicon by culturing the replicon cells in the presence of SOF. Sequencing analysis showed that the selected replicon harbored two mutations K74R and S282T in NS5B. Reverse genetics analysis showed that while PR52D4 consisting of either single mutation K74R or S282T could not replicate efficiently, the engineering of the both mutations led to a replication-competent and SOF-resistant PR52D4 replicon. Furthermore, we showed that the K74R mutation could also rescue the replication deficiency of the S282T mutation in Con1, another GT1b replicon as well as in JFH1, a GT2a replicon. Structural modeling analysis suggested that K74R might help maintain an active catalytic conformation of S282T by engaging with Y296. In conclusion, we identified the combination of two NS5B mutations S282T and K74R as a novel RAS that confers a substantial resistance to SOF while retains the HCV replication capacity.

Global, regional, and national prevalence of hepatitis B infection in the general and key populations living with HIV: a systematic review and meta-analysis protocol.

BACKGROUND: Hepatitis B causes death mainly due to liver disease worldwide. Human immunodeficiency virus increases the pathological effect of hepatitis viruses and potentiates re-activation of latent hepatitis infections as a result of reduced immunity. Because of the same modes of transmission shared by the two infections, HBV represents an important cause of co-morbidity and mortality among people living with HIV; hence, the aim of this review is to determine the prevalence of HBV among people living with HIV. METHODS: This systematic review and meta-analysis will include cross-sectional, case-control, and cohort studies of patients positive for HBV and HIV irrespective of their countries. All pertinent articles published on hepatitis B in people living with HIV from January 1, 1990, to July 31, 2017, without any language restriction will be searched in PubMed/MEDLINE, Global Index Medicus Web of Science, and Excerpta Medica Database. Two review authors will independently assess the relevance of all titles and abstracts identified from the electronic searches. The study-specific estimates will be pooled through a random-effects meta-analysis model to obtain an overall summary estimate of the prevalence of HBV across studies. We will assess statistical heterogeneity and pool clinically homogeneous studies. On the other hand, we will evaluate statistical heterogeneity by the chi-squared test on Cochrane's Q statistic. Symmetry of funnel plots and Egger's test will be used to detect the presence of publication and selective reporting bias. In the case of publication bias, we will report estimates after adjustment on publication bias using the trim-and-fill method. We will assess inter-rater agreement between investigators for study inclusion, data extraction, and methodological quality assessment using Kappa Cohen's coefficient. This protocol will comply with the guidelines for meta-analyses and systematic reviews of Preferred Reporting Items for Systematic Review and Meta-Analysis (PRISMA). DISCUSSION: To our knowledge, this is the first systematic review and meta-analysis protocol to report the prevalence of HBV in people living with HIV. We believe its outcomes will be of utility in providing insights on the characteristics of HBV epidemic in people living with HIV, and draw more attention of public health services to this association. SYSTEMATIC REVIEW REGISTRATION: PROSPERO CRD42017073124.

Relationship between estimated cardiovascular disease risk and insulin resistance in a black African population living with HIV: a cross-sectional study from Cameroon.

OBJECTIVES: Cardiovascular disease (CVD) and metabolic diseases are growing concerns among patients with HIV infection as a consequence of the improving survival of this population. We aimed to assess the relationship between CVD risk and insulin resistance in a group of black African individuals with HIV infection. METHODS: This cross-sectional study involved patients with HIV infection aged 30-74 years and followed up at the Yaoundé Central Hospital, Cameroon. Absolute CVD risk was calculated using the Framingham and the DAD CVD risk equations while the HOMA-IR index was used to assess insulin resistance (index ≥2.1). RESULTS: A total of 452 patients (361 women; 80%) were screened. The mean age was 44.4 years and most of the respondents were on antiretroviral therapy (88.5%). The median 5-year cardiovascular risk was 0.7% (25th-75th percentiles: 0.2-2.0) and 0.6% (0.3-1.3) according to the Framingham and DAD equations respectively. Of all participants, 47.3% were insulin resistant. The Framingham equation derived absolute CVD risk was significantly associated with insulin resistance; while no linear association was found using the DAD equation. CONCLUSION: The relationship between cardiovascular risk and insulin resistance in black African patients with HIV infection seems to depend on the cardiovascular risk equation used.