Basic Study
Copyright ©The Author(s) 2018. Published by Baishideng Publishing Group Inc. All rights reserved.
World J Gastroenterol. Feb 14, 2018; 24(6): 680-692
Published online Feb 14, 2018. doi: 10.3748/wjg.v24.i6.680
Analysis of hepatitis B virus preS1 variability and prevalence of the rs2296651 polymorphism in a Spanish population
Rosario Casillas, David Tabernero, Josep Gregori, Irene Belmonte, Maria Francesca Cortese, Carolina González, Mar Riveiro-Barciela, Rosa Maria López, Josep Quer, Rafael Esteban, Maria Buti, Francisco Rodríguez-Frías
Rosario Casillas, David Tabernero, Irene Belmonte, Maria Francesca Cortese, Carolina González, Rosa Maria López, Francisco Rodríguez-Frías, Liver Pathology Unit, Departments of Biochemistry and Microbiology, Hospital Universitari Vall d’Hebron, Universitat Autònoma de Barcelona, Barcelona 08035, Spain
Rosario Casillas, Josep Gregori, Maria Francesca Cortese, Josep Quer, Liver Unit, Liver Disease Laboratory-Viral Hepatitis, Vall d’Hebron Institut Recerca-Hospital Universitari Vall d’Hebron, Universitat Autònoma de Barcelona, Barcelona 08035, Spain
David Tabernero, Josep Gregori, Mar Riveiro-Barciela, Josep Quer, Rafael Esteban, Maria Buti, Francisco Rodríguez-Frías, Centro de Investigación Biomédica en Red de Enfermedades Hepáticas y Digestivas (CIBERehd), Instituto de Salud Carlos III, Madrid 28029, Spain
Josep Gregori, Roche Diagnostics SL, Sant Cugat del Vallès 08174, Spain
Mar Riveiro-Barciela, Rafael Esteban, Maria Buti, Liver Unit, Department of Internal Medicine, Hospital Universitari Vall d'Hebron, Universitat Autònoma de Barcelona, Barcelona 08035, Spain
Author contributions: Buti M and Rodríguez-Frías F equally contributed to designing the research; Tabernero D and López RM coordinated the research. Casillas R and Belmonte I designed the experiments; Casillas R and González C performed the experiments, Casillas R, Tabernero D, Gregori J, Riveiro-Barciela M, and Quer J analyzed data acquired during the experiments and interpreted the results, Casillas R, Tabernero D and Belmonte I drafted the manuscript; Cortese MF, Buti M, Esteban R and Rodríguez-Frías F critically reviewed the manuscript.
Supported by Instituto de Salud Carlos III, No. PI14/01416 and No. PI15/00856, cofinanced by the European Regional Development Fund (ERDF); and the Gilead Fellowship Program, No. GLD14-00296.
Institutional review board statement: The study was reviewed and approved by the Clinical Research Ethics Committee (CEIC) of Hospital Universitari Vall d’Hebron.
Conflict-of-interest statement: Josep Gregori is an employee of Roche Diagnostics, SL.
Data sharing statement: No additional data are available.
Open-Access: This article is an open-access article which was selected by an in-house editor and fully peer-reviewed by external reviewers. It is distributed in accordance with the Creative Commons Attribution Non Commercial (CC BY-NC 4.0) license, which permits others to distribute, remix, adapt, build upon this work non-commercially, and license their derivative works on different terms, provided the original work is properly cited and the use is non-commercial. See: http://creativecommons.org/licenses/by-nc/4.0/
Correspondence to: David Tabernero, PhD, Research Scientist, Liver Pathology Unit, Departments of Biochemistry and Microbiology, Hospital Universitari Vall d’Hebron (HUVH), Passeig Vall d’Hebron 119-129, clinical laboratories, Barcelona 08035, Spain. david.tabernero@ciberehd.org
Telephone: +34-932-746897
Received: August 29, 2017
Peer-review started: September 28, 2017
First decision: October 18, 2017
Revised: December 25, 2017
Accepted: January 18, 2018
Article in press: January 18, 2018
Published online: February 14, 2018
Abstract
AIM

To determine the variability/conservation of the domain of hepatitis B virus (HBV) preS1 region that interacts with sodium-taurocholate cotransporting polypeptide (hereafter, NTCP-interacting domain) and the prevalence of the rs2296651 polymorphism (S267F, NTCP variant) in a Spanish population.

METHODS

Serum samples from 246 individuals were included and divided into 3 groups: patients with chronic HBV infection (CHB) (n = 41, 73% Caucasians), patients with resolved HBV infection (n = 100, 100% Caucasians) and an HBV-uninfected control group (n = 105, 100% Caucasians). Variability/conservation of the amino acid (aa) sequences of the NTCP-interacting domain, (aa 2-48 in viral genotype D) and a highly conserved preS1 domain associated with virion morphogenesis (aa 92-103 in viral genotype D) were analyzed by next-generation sequencing and compared in 18 CHB patients with viremia > 4 log IU/mL. The rs2296651 polymorphism was determined in all individuals in all 3 groups using an in-house real-time PCR melting curve analysis.

RESULTS

The HBV preS1 NTCP-interacting domain showed a high degree of conservation among the examined viral genomes especially between aa 9 and 21 (in the genotype D consensus sequence). As compared with the virion morphogenesis domain, the NTCP-interacting domain had a smaller proportion of HBV genotype-unrelated changes comprising > 1% of the quasispecies (25.5% vs 31.8%), but a larger proportion of genotype-associated viral polymorphisms (34% vs 27.3%), according to consensus sequences from GenBank patterns of HBV genotypes A to H. Variation/conservation in both domains depended on viral genotype, with genotype C being the most highly conserved and genotype E the most variable (limited finding, only 2 genotype E included). Of note, proline residues were highly conserved in both domains, and serine residues showed changes only to threonine or tyrosine in the virion morphogenesis domain. The rs2296651 polymorphism was not detected in any participant.

CONCLUSION

In our CHB population, the NTCP-interacting domain was highly conserved, particularly the proline residues and essential amino acids related with the NTCP interaction, and the prevalence of rs2296651 was low/null.

Keywords: Hepatitis B virus, Hepatitis B virus preS1 region, Sodium-taurocholate co-transporting polypeptide, NTCP-interacting domain, Virion morphogenesis domain, SNP rs2296651, Next-generation sequencing, Real-time PCR melting curves

Core tip: Simultaneous analysis of both viral and host features important for hepatitis B virus (HBV) entry into hepatocytes provided locally relevant preliminary information in a population previously uncharacterized in this regard. In-house developed next-generation sequencing was successfully used to investigate the variability of the preS1 region of the HBV large envelope protein, and real-time PCR melting curve analysis to detect the rs2296651 polymorphism (NTCP variant, S267F) in the HBV cellular receptor, NTCP. Results in a limited sample indicate that the features analyzed would not decrease the effectiveness of new therapies to block NTCP and avert HBV binding to hepatocytes in our particular CHB population.