Cellular Mechanism for Impaired Hepatitis C Virus Clearance by Interferon Associated with IFNL3 Gene Polymorphisms Relates to Intrahepatic Interferon-λ Expression

Mechanisms of Sorafenib Resistance in HCC Culture Relate to the Impaired Membrane Expression of Organic Cation Transporter 1 (OCT1)

Introduction

Sorafenib, an FDA-approved drug for advanced hepatocellular carcinoma (HCC) treatment, encounters resistance in many patients. Deciphering the mechanisms underlying sorafenib resistance is crucial for devising alternative strategies to overcome it.

Aim

This study aimed to investigate sorafenib resistance mechanisms using a diverse panel of HCC cell lines.

Methods

HCC cell lines were subjected to continuous sorafenib treatment, and stable cell lines (Huh 7.5 and Huh 7PX) exhibiting sustained growth in its presence were isolated. The investigation of drug resistance mechanisms involved a comparative analysis of drug-targeted signal transduction pathways (EGFR/RAF/MEK/ERK/Cyclin D), sorafenib uptake, and membrane expression of the drug uptake transporter.

Results

HCC cell lines (Huh 7.5 and Huh 7PX) with a higher IC50 (10μM) displayed a more frequent development of sorafenib resistance compared to those with a lower IC50 (2-4.8μM), indicating a potential impact of IC50 variation on initial treatment response. Our findings reveal that activated overexpression of Raf1 kinases and impaired sorafenib uptake, mediated by reduced membrane expression of organic cation transporter-1 (OCT1), contribute to sorafenib resistance in HCC cultures. Stable expression of the drug transporter OCT1 through cDNA transfection or adenoviral delivery of OCT1 mRNA increased sorafenib uptake and successfully overcame sorafenib resistance. Additionally, consistent with sorafenib resistance in HCC cultures, cirrhotic liver-associated human HCC tumors often exhibited impaired membrane expression of OCT1 and OCT3.

Conclusion

Intrinsic differences among HCC cell clones, affecting sorafenib sensitivity at the expression level of Raf kinases, drug uptake, and OCT1 transporters, were identified. This study underscores the potential of HCC tumor targeted OCT1 expression to enhance sorafenib treatment response.

Genome-wide mining of diversity and evolutionary signatures revealed selective hotspots in Indian Sahiwal cattle

The Sahiwal cattle breed is the best indigenous dairy cattle breed, and it plays a pivotal role in the Indian dairy industry. This is due to its exceptional milk-producing potential, adaptability to local tropical conditions, and its resilience to ticks and diseases. The study aimed to identify selective sweeps and estimate intrapopulation genetic diversity parameters in Sahiwal cattle using ddRAD sequencing-based genotyping data from 82 individuals. After applying filtering criteria, 78,193 high-quality SNPs remained for further analysis. The population exhibited an average minor allele frequency of 0.221 ± 0.119. Genetic diversity metrics, including observed (0.597 ± 0.196) and expected heterozygosity (0.433 ± 0.096), nucleotide diversity (0.327 ± 0.114), the proportion of polymorphic SNPs (0.726), and allelic richness (1.323 ± 0.134), indicated ample genomic diversity within the breed. Furthermore, an effective population size of 74 was observed in the most recent generation. The overall mean linkage disequilibrium (r2) for pairwise SNPs was 0.269 ± 0.057. Moreover, a greater proportion of short Runs of Homozygosity (ROH) segments were observed suggesting that there may be low levels of recent inbreeding in this population. The genomic inbreeding coefficients, computed using different inbreeding estimates (FHOM, FUNI, FROH, and FGROM), ranged from -0.0289 to 0.0725. Subsequently, we found 146 regions undergoing selective sweeps using five distinct statistical tests: Tajima's D, CLR, |iHS|, |iHH12|, and ROH. These regions, located in non-overlapping 500 kb windows, were mapped and revealed various protein-coding genes associated with enhanced immune systems and disease resistance (IFNL3, IRF8, BLK), as well as production traits (NRXN1, PLCE1, GHR). Notably, we identified interleukin 2 (IL2) on Chr17: 35217075-35223276 as a gene linked to tick resistance and uncovered a cluster of genes (HSPA8, UBASH3B, ADAMTS18, CRTAM) associated with heat stress. These findings indicate the evolutionary impact of natural and artificial selection on the environmental adaptation of the Sahiwal cattle population.

Interleukin 28B Polymorphism as a Predictor of Sustained Virological Response to Sofosbuvir-Based Therapy for Hepatitis C Virus Patients

In various genome-wide correlation studies, interleukin (IL)28B gene polymorphism has been strongly correlated with both the therapeutic and spontaneous mediated clearance of hepatitis C virus (HCV). Therefore, this study aimed to evaluate the genotype and allele frequency distributions of IL28B (rs12979860) in patients with chronic hepatitis C and assess the IL28B polymorphisms as predictors of sustained virological response to SOF-based therapy for HCV in Egyptian patients. This retrospective case-control study was conducted on 54 chronic HCV patients who completed treatment with SOF/DCV ± RBV for 12 weeks and responded to treatment with SVR12 (the responder group) as a control group, and 54 chronic HCV patients who completed treatment with SOF/DCV ± RBV for 12 weeks and did not respond to treatment and failed to achieve SVR12 (the non-responder group) as a case group. The CC genotype frequency of IL-28B (rs12979860) was greater in the responder group (51.9%). In contrast, the TT genotype frequency was higher in the non-responder group (48.1%) (p < 0.001), and the T allele significantly increased the risk of non-responses by 3.13 fold. Therefore IL-28B (rs12979860) SNP could be used as a genetic predictor of sustained virological response to SOF+DCV ± RBV-based HCV treatment in Egyptian patients.

SNPs of the IFNL favour spontaneous clearance of HCV infection in children

BACKGROUND

Both spontaneous and treatment-induced clearance of hepatitis C virus (HCV) in adults have been associated with genetic polymorphisms in the interferon-λ genes. The aim of the present study was to confirm the association between the rs12979860 and evaluate the association between the rs368234815 and the rs4803217 single-nucleotide polymorphisms (SNPs) of the interferon-λ genes and the outcome of the infection in children.

METHODS

Alleles and genotypes frequencies of 32 children, who presented spontaneous clearance of the virus and 135 children, with viral persistence were compared with ethnically matched controls obtained from the 1000 Genomes Project and the International HapMap Project databases.

RESULTS

The frequencies of the C/C genotype of rs12979860, the TT/TT of the rs368234815 and the A/C of the rs4803217 were higher in the clearance group than in children with viral persistence (C/C versus T/T + C/T odds ratio (OR): 2.6; 90% confidence intervals (CI): 1.3-5; p = 0.01; TT/TT versus ΔG/TT + ΔG/ΔG OR: 2.8; 90% CI: 1.4-5.5; p = 0.01; and A/A versus A/C OR: 8.3; 90% CI: 1.5-45.9; p = 0.017, respectively) and with the ethnically matched controls.

CONCLUSIONS

The rs12979860, the rs368234815 and the rs4803217 SNPs are associated with spontaneous clearance of HCV in children.

IMPACT

Innate immune system response has a key role in the outcome of vertically acquired HCV infection in children. The rs12979860, the rs368234815 and the rs4803217 SNPs are associated with spontaneous clearance of HCV in children. Interferons-λ activate the Janus kinase-Stat pathway, which in turn induces several interferon-stimulated genes, leading to suppression of HCV replication both in vivo and in vitro.

Human host genetics and susceptibility to ZIKV infection

Managing emerging infectious diseases is a current challenge in the fields of microbiology and epidemiology. Indeed, among other environmental and human-related factors, climate change and global warming favor the emergence of new pathogens. The recent Zika virus (ZIKV) epidemic, of which the large and rapid spread surprised the scientific community, is a reminder of the importance to study viruses currently responsible for sporadic infections. Increasing our knowledge of key factors involved in emerging infections is essential to implement specific monitoring that can be oriented according to the pathogen, targeted population, or at-risk environment. Recent technological developments, such as high-throughput sequencing, genome-wide association studies and CRISPR screenings have allowed the identification of human single nucleotide polymorphisms (SNPs) involved in infectious disease outcome. This review focuses on the human genetic host factors that have been identified and shown to be associated with the pathogenesis of ZIKV infection and candidate SNP targets.

Polymorphism rs368234815 of interferon lambda 4 gene and spontaneous clearance of hepatitis C virus in haemodialysis patients: a case-control study

BACKGROUND

In non-uremic subjects, IFNL4 rs368234815 predicts HCV clearance. We investigated whether rs368234815 is associated with spontaneous HCV clearance in haemodialysis patients and whether it is a stronger predictor of HCV resolution than the IFNL polymorphisms already associated with HCV clearance in dialysis subjects. We also evaluated an association of rs368234815 with patients` survival and alterations in transcription factor binding sites (TFBS) caused by IFNL polymorphisms.

METHODS

Among 161 haemodialysis patients with positive anti-HCV antibodies, 68 (42.2%) spontaneously resolved HCV infection, whereas 93 remained HCV RNA positive. Patients were tested for near IFNL3 rs12980275, IFNL3 rs4803217, IFNL4 rs12979860, IFNL4 rs368234815, and near IFNL4 rs8099917. IFNL4 rs368234815 polymorphism (TT/TT, ΔG/TT, ΔG/ΔG) was genotyped by restriction fragment length polymorphism analysis; other IFNL polymorphisms - by high resolution melting curve analysis. We used the Kaplan-Meier method with the log-rank test for survival analysis. In silico analysis included the use of ENCODE TFBS ChIP-seq data, HOCOMOCO, JASPAR CORE, and CIS-BP databases, and FIMO software.

RESULTS

The probability (OR, 95%CI, P) of spontaneous HCV clearance for rs368234815 TT/TT patients was higher than for the ΔG allele carriers (2.63, 1.38-5.04, 0.003). This probability for other major homozygotes varied between 2.80, 1.45-5.43, 0.002 for rs12980275 and 2.44, 1.27-4.69, 0.007 for rs12979860. In the additive model, rs368234815 TT/TT was the strongest predictor of HCV clearance (6.38, 1.69-24.2, 0.003). Survival analysis suggested an association of the ΔG allele with mortality due to neoplasms (log-rank P = 0.005). The rs368234815 ∆G allele caused TFBS removal for PLAGL1.

CONCLUSIONS

In haemodialysis patients, the association of rs368234815 with the spontaneous HCV clearance is better than that documented for other IFNL3/IFNL4 polymorphisms only in the additive mode of inheritance. However, identifying the homozygosity in the variant ∆G allele of rs368234815 means a more potent prediction of persistent HCV infection in haemodialysis subjects that we observe in the case of the variant homozygosity of other tested IFNL3/IFNL4 polymorphisms. Removal of PLAGL1 TFBS in subjects harbouring the rs368234815 ∆G allele may contribute to cancer susceptibility. The association of rs368234815 with cancer-related mortality needs further studies in HCV-exposed subjects.

Genetic and epigenetic regulation of natural resistance to HIV-1 infection: new approaches to unveil the HESN secret

Introduction: Since the identification of HIV, several studies reported the unusual case of small groups of subjects showing natural resistance to HIV infection. These subjects are referred to as HIV-1-exposed seronegative (HESN) individuals and include people located in different areas, with diverse ethnic backgrounds and routes of exposure. The mechanism/s responsible for protection from infection in HESN individuals are basically indefinite and most likely are multifactorial.Areas covered: Host factors, including genetic background as well as natural and acquired immunity, have all been associated with this phenomenon. Recently, epigenetic factors have been investigated as possible determinants of reduced susceptibility to HIV infection. With the advent of the OMICS era, the availability of techniques such as GWAS, RNAseq, and exome-sequencing in both bulk cell populations and single cells will likely lead to great strides in the understanding of the HESN mystery.Expert opinion: The employment of increasingly sophisticated techniques is allowing the gathering of enormous amounts of data. The integration of such information will provide important hints that could lead to the identification of viral and host correlates of protection against HIV infection, allowing the development of more effective preventative and therapeutic regimens.

Genetic Polymorphisms within Interferon-λ Region and Interferon-λ3 in the Human Pathophysiology: Their Contribution to Outcome, Treatment, and Prevention of Infections with Hepatotropic Viruses

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Genetic polymorphisms within the interferon λ (IFN-λ) chromosomal region, mainly rs12979860 of IFN-λ4 gene (IFNL4), are known as associated with spontaneous hepatitis C virus (HCV) resolution and sustained viral response to therapy with pegylated interferon- α and ribavirin. Strong linkage disequilibrium of IFNL4 rs12979860 with IFNL4 rs368234815, which is casually associated with HCV spontaneous and therapeutical eradication, at least partially explains favorable HCV outcomes attributed to major homozygosity in rs12979860. Effects of IFN-based antiviral treatment are associated with pretreatment expression of the IFN-λ1 receptor, expression of hepatic IFN-stimulated genes, production of IFN- λ4, and preactivation of the JAK-STAT signaling. Nowadays direct-acting antivirals (DAAs) became a potent tool in the treatment of hepatitis C, but IFN-λs are still under investigation as potential antivirals and might be an option in HCV infection (DAA resistance, recurrent viremia, adverse effects).

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Patients with altered immunocompetence are especially prone to infections. In uremic subjects, polymorphisms within the IFN-λ chromosomal region associate with spontaneous HCV clearance, similarly like in the non-uremic population. Circulating IFN-λ3 shows a positive correlation with plasma titers of antibodies to surface antigen of hepatitis B virus (anti-HBs), which are crucial for protection against hepatitis B virus. More efficient anti-HBs production in the presence of higher IFN-λ3 levels might occur due to IFN-λ3-induced regulation of indoleamine 2,3-dioxygenase (IDO) expression. IFN-stimulated response element is a part of IDO gene promoter. It is worth further investigation whether IDO gene, circulating IDO, genetic polymorphisms within the IFN-λ region, and circulating IFN-λ3 act in concordance in immunological response to hepatotropic viruses.

Circulating Interferon-λ3, Responsiveness to HBV Vaccination, and HBV/HCV Infections in Haemodialysis Patients

The IFN-λ3 gene (IFNL3) plays a role in HCV clearance. We investigated circulating IFN-λ3 and IFNL3 SNPs in haemodialysis patients who differed in their response to HBV vaccination and their HBV/HCV infection status. In 201 patients, plasma IFN-λ3 was determined using ELISA. IFNL3 SNPs (rs12979860, rs8099917) were genotyped using HRM analysis. Differences in IFN-λ3 levels were shown between responders and nonresponders to HBV vaccination and between HBsAg-positive patients and those who developed anti-HBs after infection and became HBsAg negative. HBV vaccine responders without HCV resolution revealed lower IFN-λ3 than noninfected responders. HBsAg/HCV RNA-positive subjects showed lower IFN-λ3 than patients positive only for HCV RNA or subjects who resolved both infections. Circulating IFN-λ3 correlated positively with anti-HBs and negatively with positive HCV RNA testing in the adjusted regression analyses. HBV vaccine nonresponders, HBsAg-positive patients, and subjects with replicating HCV composed a group with unfavourable outcomes. Responders to HBV vaccination, subjects who became HBsAg negative, and those who cleared HCV were analysed as having favourable outcomes. The latter showed higher IFN-λ3 but did not differ in distribution of IFNL3 SNPs compared with subjects with unfavourable outcomes. Higher IFN-λ3 concentrations are associated with response to HBV vaccination, self-limited HBV infection, and HCV resolution.

IFN-λ4 Attenuates Antiviral Responses by Enhancing Negative Regulation of IFN Signaling

Type III IFNs are important mediators of antiviral immunity. IFN-λ4 is a unique type III IFN because it is produced only in individuals who carry a dG allele of a genetic variant rs368234815-dG/TT. Counterintuitively, those individuals who can produce IFN-λ4, an antiviral cytokine, are also less likely to clear hepatitis C virus infection. In this study, we searched for unique functional properties of IFN-λ4 that might explain its negative effect on hepatitis C virus clearance. We used fresh primary human hepatocytes (PHHs) treated with recombinant type III IFNs or infected with Sendai virus to model acute viral infection and subsequently validated our findings in HepG2 cell line models. Endogenous IFN-λ4 protein was detectable only in Sendai virus-infected PHHs from individuals with the dG allele, where it was poorly secreted but highly functional, even at concentrations < 50 pg/ml. IFN-λ4 acted faster than other type III IFNs in inducing antiviral genes, as well as negative regulators of the IFN response, such as USP18 and SOCS1 Transient treatment of PHHs with IFN-λ4, but not IFN-λ3, caused a strong and sustained induction of SOCS1 and refractoriness to further stimulation with IFN-λ3. Our results suggest unique functional properties of IFN-λ4 that can be important in viral clearance and other clinical conditions.

Genome-to-genome analysis highlights the effect of the human innate and adaptive immune systems on the hepatitis C virus

Outcomes of hepatitis C virus (HCV) infection and treatment depend on viral and host genetic factors. We use human genome-wide genotyping arrays and new whole-genome HCV viral sequencing technologies to perform a systematic genome-to-genome study of 542 individuals chronically infected with HCV, predominately genotype 3. We show that both HLA alleles and interferon lambda innate immune system genes drive viral genome polymorphism, and that IFNL4 genotypes determine HCV viral load through a mechanism that is dependent on a specific polymorphism in the HCV polyprotein. We highlight the interplay between innate immune responses and the viral genome in HCV control.

Interferon Lambda: Modulating Immunity in Infectious Diseases

Interferon lambdas (IFN-λs; IFNL1-4) modulate immunity in the context of infections and autoimmune diseases, through a network of induced genes. IFN-λs act by binding to the heterodimeric IFN-λ receptor (IFNLR), activating a STAT phosphorylation-dependent signaling cascade. Thereby hundreds of IFN-stimulated genes are induced, which modulate various immune functions via complex forward and feedback loops. When compared to the well-characterized IFN-α signaling cascade, three important differences have been discovered. First, the IFNLR is not ubiquitously expressed: in particular, immune cells show significant variation in the expression levels of and susceptibilities to IFN-λs. Second, the binding affinities of individual IFN-λs to the IFNLR varies greatly and are generally lower compared to the binding affinities of IFN-α to its receptor. Finally, genetic variation in the form of a series of single-nucleotide polymorphisms (SNPs) linked to genes involved in the IFN-λ signaling cascade has been described and associated with the clinical course and treatment outcomes of hepatitis B and C virus infection. The clinical impact of IFN-λ signaling and the SNP variations may, however, reach far beyond viral hepatitis. Recent publications show important roles for IFN-λs in a broad range of viral infections such as human T-cell leukemia type-1 virus, rotaviruses, and influenza virus. IFN-λ also potentially modulates the course of bacterial colonization and infections as shown for Staphylococcus aureus and Mycobacterium tuberculosis. Although the immunological processes involved in controlling viral and bacterial infections are distinct, IFN-λs may interfere at various levels: as an innate immune cytokine with direct antiviral effects; or as a modulator of IFN-α-induced signaling via the suppressor of cytokine signaling 1 and the ubiquitin-specific peptidase 18 inhibitory feedback loops. In addition, the modulation of adaptive immune functions via macrophage and dendritic cell polarization, and subsequent priming, activation, and proliferation of pathogen-specific T- and B-cells may also be important elements associated with infectious disease outcomes. This review summarizes the emerging details of the IFN-λ immunobiology in the context of the host immune response and viral and bacterial infections.

Type III Interferons in Hepatitis C Virus Infection

The interferon (IFN)-λ family of type III cytokines includes the closely related interleukin (IL)-28A (IFN-λ2), IL-28B (IFN-λ3), and IL-29 (IFN-λ1). They signal through the Janus kinases (JAK)-signal transducers and activators of transcription pathway and promote an antiviral state by the induction of expression of several interferon-stimulated genes (ISGs). Contrary to type I IFNs, the effect of IFN-λ cytokines is largely limited to epithelial cells due to the restricted pattern of expression of their specific receptor. Several genome-wide association studies have established a strong correlation between polymorphism in the region of IL-28B gene (encoding for IFN-λ3) and both spontaneous and therapeutic IFN-mediated clearance of hepatitis C virus (HCV) infection, but the mechanism(s) underlying this enhanced viral clearance are not fully understood. IFN-λ3 directly inhibits HCV replication, and in vitro studies suggest that polymorphism in the IFN-λ3 and its recently identified overlapping IFN-λ4 govern the pattern of ISGs induced upon HCV infection of hepatocytes. IFN-λ can also be produced by dendritic cells, and apart from its antiviral action on hepatocytes, it can regulate the inflammatory response of monocytes/macrophages, thus acting at the interface between innate and adaptive immunity. Here, we review the current state of knowledge about the role of IFN-λ cytokines in mediating and regulating the immune response during acute and chronic HCV infections.