Recognition of genetic factors influencing the progression of hepatitis C : potential for personalized therapy

Secreted protein acidic and rich in cysteine gene variants: Impact on susceptibility and survival of hepatocellular carcinoma patients

BACKGROUND AND AIM

Secreted protein acidic and rich in cysteine (SPARC) is a glycoprotein involved in extracellular matrix remodeling, which regulates cell growth. It could be involved in hepatic fibrogenesis related to chronic inflammations, hepatocellular carcinoma (HCC) angiogenesis, and tumor progression. We aimed to study the expressions of single nucleotide polymorphisms in the SPARC gene and their impact on susceptibility and survival of HCC patients.

METHODS

We conducted a case-control study on 200 HCC patients and 50 matched healthy controls. All patients were subjected to laboratory investigations, ultrasound, and real-time polymerase chain reaction to detect the genetic polymorphisms (rs3210714, rs11950384, and rs7719521) in the SPARC gene in the blood.

RESULTS

One hundred sixty (80%) patients were men with a mean age of 43 years. The SPARC gene showed a significant higher prevalence of rs3210714 mutation (i.e. AA or AG) and a significant lower prevalence of rs11950384 mutation (i.e. AA or AC) among HCC patients in comparison with controls (83% vs 22%, P ≤ 0.001) and (65.5 vs 86%, P = 0.005), respectively, while rs7719521 mutation did not reach significance. On univariate and multivariate analyses, elder age and having at least one copy of the mutant rs3210714 were associated with a significantly increased risk of HCC (P < 0.001 for both), whereas the presence of at least one copy of the mutant rs11950384 carried a significantly reduced risk of having HCC (P < 0.01). Overall survival did not differ significantly between any of the SPARC gene mutation groups.

CONCLUSIONS

The SPARC gene polymorphisms had a diverse impact on the susceptibility of HCC due to its ability to inhibit or promote tumor progression. SPARC gene polymorphisms were not related to survival of our HCC patients, and probably, this needs further analysis of other SPARC gene nucleotides.

The relationships among host transcriptional responses reveal distinct signatures underlying viral infection-disease associations

Genome-scale DNA microarrays and computational biology facilitate new understanding of viral infections at the system level. Recent years have witnessed a major shift from microorganism-centric toward host-oriented characterization and categorization of viral infections and infection related diseases. We established host transcriptional response (HTR) relationships among 23 different types of human viral pathogens based on calculating HTR similarities using computational integration of 587 public available gene expression profiles. We further identified five virus clusters that show consensus internal HTRs and defined cluster signatures using common dysregulated genes. Individual cluster signature genes were distinguished from one another, and functional analysis revealed common and specific host cellular bioprocesses and signaling pathways involved in confronting viral infections. Through literature investigation and support from epidemiological studies, these were confirmed to be important gene factors associating viral infections with cluster-common and cluster-specific non-infectious human disease(s). Our analyses were the first to feature differential HTRs to viral infections as clusters, and they present a new perspective for understanding infection-disease associations and the underlying pathogeneses.

Current and future therapies for hepatitis C virus infection

Only 20 years after the discovery of the Hepatitis C Virus (HCV), a cure is now likely for most people affected by this chronic infection, which carries a substantial disease burden, not only in the United States but also worldwide.1 The recent approval of two direct-acting antiviral agents that specifically inhibit viral replication has dramatically increased the viral clearance rate, from less than 10% with the initial regimen of interferon monotherapy to more than 70% with current therapy. Moreover, many other drugs targeting viral or host factors are in development, and some will almost certainly be approved in the coming years. The questions of who should be treated and with what regimen will be increasingly complex to address and will require careful consideration. As therapy improves, systemwide identification and care of patients who need treatment will be the next challenge. Because most infected persons are unaware of their diagnosis, the Centers for Disease Control and Prevention recently recommended screening for HCV all persons born between 1945 and 1965.2 ,3 It is anticipated that in the course of such a screening process, a large number of persons will be found to be infected with the virus; whether it will be possible to treat all these people is unclear. This article reviews the current therapy for HCV infection and the landscape of drug development.

Portal, but not lobular, macrophages express matrix metalloproteinase-9: association with the ductular reaction and fibrosis in chronic hepatitis C

BACKGROUND

Liver macrophages are a heterogeneous cell population that produces factors involved in fibrogenesis and matrix turnover, including matrix metalloproteinase (MMP) -9. During liver injury, their close proximity to hepatic progenitor cells and the ductular reaction may enable them to regulate liver repair and fibrosis.

AIMS

To enumerate and characterise liver macrophages in patients with chronic hepatitis C, to determine whether a distinct population of macrophages is associated with the ductular reaction and portal fibrosis.

METHODS

Immunostaining for macrophage markers (CD68, CD163, CCR2), the ductular reaction (keratin-7) and MMP-9 was performed in liver biopsy sections from patients with chronic hepatitis C virus (HCV) (n = 85).

RESULTS

Portal tracts were more densely populated with macrophages (10.5 ± 0.36 macrophages/HPF) than lobules (7.2 ± 0.16 macrophages/HPF, P < 0.001) and macrophages were found in close proximity to the ductular reaction. ≥30% of portal and periductal macrophages expressed MMP-9 and these were significantly associated with increasing stage of fibrosis (rs  = 0.58, 0.68, respectively, both P < 0.001). In contrast, MMP-9(+) macrophages were largely absent in lobular regions and non-diseased liver. Hepatic MMP-9 mRNA levels and gelatinolytic activity were significantly associated with stage of fibrosis (rs  = 0.47, rs  = 0.89, respectively, both P < 0.001). Furthermore, a second distinct CCR2(+) macrophage population was localised to the centrilobular regions and was predominantly absent from portal and periductal areas.

CONCLUSIONS

These findings demonstrate significant regional differences in macrophage phenotypes, suggesting that there are at least two populations of liver macrophages. We propose that these populations have distinct contributions to the pathogenesis of chronic HCV-related liver disease.

Lack of evidence to support the association of a single IL28B genotype SNP rs12979860 with the HTLV-1 clinical outcomes and proviral load

BACKGROUND

The Interleukin 28B (IL28B) rs12979860 polymorphisms was recently reported to be associated with the human T-cell leukemia virus type 1 (HTLV-1) proviral load (PvL) and the development of the HTLV-1-associated myelopathy/tropical spastic paraparesis (HAM/TSP).

METHODS

In an attempt to examine this hypothesis, we assessed the association of the rs12979860 genotypes with HTLV-1 PvL levels and clinical status in 112 unrelated Brazilian subjects (81 HTLV-1 asymptomatic carriers, 24 individuals with HAM/TSP and 7 with Adult T cell Leukemia/Lymphoma (ATLL)).

RESULTS

All 112 samples were successfully genotyped and their PvLs compared. Neither the homozygote TT nor the heterozygote CT mutations nor the combination genotypes (TT/CT) were associated with a greater PvL. We also observed no significant difference in allele distribution between asymptomatic carriers and patients with HTLV-1 associated HAM/TSP.

CONCLUSIONS

Our study failed to support the previously reported positive association between the IL28B rs12979860 polymorphisms and an increased risk of developing HAM/TSP in the Brazilian population.

Liver fibrosis: from animal models to mapping of human risk variants

Liver fibrosis is the sequel of chronic liver diseases and the main reason for increased mortality in affected patients. The extent of liver fibrosis displays great interindividual variation, even after controlling for exogenous factors. Thus, host genetic factors are considered to play an important role in the process of liver scarring. From a genetic perspective, liver fibrosis is a complex trait with many genes contributing to the expression of the phenotype. In genetically manipulated and inbred animals several risk loci for liver fibrosis have been identified. Some of these loci have been replicated in case-control studies of patients with hepatitis C infection. In humans, genetic risk loci were identified by single marker studies, haplotype studies or the combination of single markers. Recently, the first genome-wide association studies have also been performed in patients with liver diseases. Some of the identified gene variants have been functionally characterized in vitro, thereby opening the potential for novel therapeutic approaches and risk stratification.

The hepatitis C virus core protein indirectly induces alpha-smooth muscle actin expression in hepatic stellate cells via interleukin-8

BACKGROUND & AIMS

Progressive deposition of liver fibrosis is a common feature of chronic hepatitis associated with hepatitis C virus (HCV) infection, and it may eventually lead to cirrhosis and liver failure. Although this fibrogenic process appears to be linked to HCV protein expression and replication via indirect mechanisms, i.e., to be mediated by virally-driven inflammation, a direct role of HCV in inducing fibrosis deposition has never been entirely excluded.

METHODS

We established an in vitro system in which the human hepatic stellate cell line LX-2 was cultured in the presence of conditioned medium from human hepatoma Huh-7 cells transduced with a lentiviral vector expressing HCV core proteins of different genotypes.

RESULTS

Treatment of LX-2 cells, with conditioned medium from Huh-7 cells expressing HCV core protein, led to the activation of alpha-smooth muscle actin expression. Among the chemokines secreted by cells transduced with HCV core, interleukin-8 was identified as the strongest inducer of alpha-smooth muscle actin expression in LX-2 and primary hepatic stellate cells. This effect was accompanied by a decrease in cell migration and increased focal contact organisation.

CONCLUSIONS

The expression of the HCV core in hepatocytes may contribute to the establishment of a profibrogenic microenvironment.

Secreted protein acidic and rich in cysteine (SPARC) gene polymorphism association with hepatocellular carcinoma in Italian patients

BACKGROUND AND AIM

Hepatocellular carcinoma (HCC) is a multifactorial disease driven by both genetic and epigenetic factors. Infection, inflammation and the immune response against hepatitis B virus and hepatitis C virus have been shown to play an important role in increasing cancer risk and promoting tumor development. In order to investigate the genetic component influencing HCC development, we analyzed 50 single nucleotide polymorphisms (SNP) spanning 34 different genes in 230 Italian patients affected by HCC and 230 controls.

METHODS

Genes were selected on the basis of their known biological function and their possible involvement in the progression or in the susceptibility to HCC was considered. SNP genotyping was performed using allelic-specific fluorescent probes.

RESULTS

For most SNP, no differences were identified between HCC patients and controls, with the exception of rs2304052, localized on the secreted protein acidic and rich in cysteine (SPARC) gene, which was significantly associated to the disease. The C allele was significantly more frequent in the HCC patients than in the healthy controls (23% vs 10%, corrected P < 0.001), as well as the CC genotype (13% vs 1%, corrected P < 0.001).

CONCLUSION

Since the presence of the rs2304052 C allele is associated with an increased risk (odds ratio: 2.76) of developing hepatocarcinoma, our results allowed us to identify a SNP in the SPARC gene correlating to HCC susceptibility.

Molecular and contextual markers of hepatitis C virus and drug abuse

The spread of hepatitis C virus (HCV) infection involves a complex interplay of social risks, and molecular factors of both virus and host. Injection drug abuse is the most powerful risk factor for HCV infection, followed by sexual transmission and additional non-injection drug abuse factors such as co-infection with other viruses and barriers to treatment. It is clearly important to understand the wider context in which the factors related to HCV infection occur. This understanding is required for a comprehensive approach leading to the successful prevention, diagnosis, and treatment of HCV. An additional consideration is that current treatments and advanced molecular methods are generally unavailable to socially disadvantaged patients. Thus, the recognition of behavioral/social, viral, and host factors as components of an integrated approach to HCV is important to help this vulnerable group. Equally important, this approach is key to the development of personalized patient treatment - a significant goal in global healthcare. In this review, we discuss recent findings concerning the impact of drug abuse, epidemiology, social behavior, virology, immunopathology, and genetics on HCV infection and the course of disease.