Basic Study
Copyright ©The Author(s) 2015. Published by Baishideng Publishing Group Inc. All rights reserved.
World J Gastroenterol. Apr 7, 2015; 21(13): 3867-3875
Published online Apr 7, 2015. doi: 10.3748/wjg.v21.i13.3867
Insulin-like growth factor-1 mRNA isoforms and insulin-like growth factor-1 receptor mRNA expression in chronic hepatitis C
Aldona Kasprzak, Agnieszka Adamek, Wiesława Przybyszewska, Przemysław Pyda, Jacek Szmeja, Agnieszka Seraszek-Jaros, Agata Lanzafame, Anna Surdacka, Iwona Mozer-Lisewska, Maria Koczorowska
Aldona Kasprzak, Wiesława Przybyszewska, Department of Histology and Embryology, Poznan University of Medical Sciences, 60-781 Poznan, Poland
Agnieszka Adamek, Iwona Mozer-Lisewska, Department of Infectious Diseases, Poznan University of Medical Sciences, 61-285 Poznan, Poland
Przemysław Pyda, Jacek Szmeja, Department of General Surgery, Gastroenterological Oncology and Plastic Surgery, Poznan University of Medical Sciences, 60-355 Poznan, Poland
Agnieszka Seraszek-Jaros, Department of Bioinformatics and Computational Biology, Chair of Clinical Pathomorphology, Poznan University of Medical Sciences, 60-529 Poznan, Poland
Agata Lanzafame, Anna Surdacka, Department and Clinics of Conservative Dentistry and Periodontology, Poznan University of Medical Sciences, 60-812, Poznan, Poland
Maria Koczorowska, Department of Molecular Virology, Adam Mickiewicz University, 61-614 Poznan, Poland
Author contributions: Kasprzak A and Adamek A contributed equally to this work; Kasprzak A and Adamek A designed the research; Kasprzak A, Adamek A, Przybyszewska W, Pyda P and Szmeja J performed the research; Kasprzak A, Adamek A, Seraszek-Jaros A, Lanzafame A, Surdacka A and Mozer-Lisewska I analyzed the data; Seraszek-Jaros A performed biostatistics; Koczorowska M contributed new reagents/analytic tools; Kasprzak A and Adamek A wrote the paper.
Supported by Minister of Education and Science, Warsaw, Poland, No. NN401009437.
Ethics approval: Committee on Bioethics, Poznan University of Medical Sciences, 61-701 Poznan, Poland (No. 22/09).
Institutional animal care and use committee: Not applicable.
Conflict-of-interest: All authors declare that they have no relevant or material financial interests that relate to the research described in this paper.
Data sharing: No additional data 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: Aldona Kasprzak, MD, PhD, Professor, Department of Histology and Embryology, Poznan University of Medical Sciences, 6 Swiecicki Street, 60-781 Poznan, Poland. akasprza@ump.edu.pl
Telephone: +48-61-8546441 Fax: +48-61-8546440
Received: August 26, 2014
Peer-review started: August 27, 2014
First decision: September 15, 2014
Revised: October 11, 2014
Accepted: January 8, 2015
Article in press: January 8, 2015
Published online: April 7, 2015
Abstract

AIM: To evaluate the expression of different insulin-like growth factor (IGF)-1 mRNA isoforms and IGF-1 receptor (IGF-1R) mRNA in hepatitis C virus (HCV)-infected livers.

METHODS: Thirty-four liver biopsy specimens from chronic hepatitis C (CH-C) patients were obtained before anti-viral therapy. Inflammatory activity (grading) and advancement of fibrosis (staging) were evaluated using a modified point scale of METAVIR. The samples were analyzed using quantitative real-time PCR technique. From fragments of liver biopsies and control liver that were divided and ground in liquid nitrogen, RNA was isolated using RNeasy Fibrous Tissue Mini Kit according to the manufacturer’s instruction. Expression levels of IGF-1 mRNA isoforms (IGF-1A, IGF-1B, IGF-1C, P1, and P2) and IGF-1R mRNA were determined through normalization of copy numbers in samples as related to reference genes: glyceraldehyde-3-phosphate dehydrogenase and hydroxymethylbilane synthase. Results on liver expression of the IGF-1 mRNA isoforms and IGF-1R transcript were compared to histological alterations in liver biopsies and with selected clinical data in the patients. Statistical analysis was performed using Statistica PL v. 9 software.

RESULTS: The study showed differences in quantitative expression of IGF-1 mRNA variants in HCV-infected livers, as compared to the control. Higher relative expression of total IGF-1 mRNA and of IGF-1 mRNAs isoforms (P1, A, and C) in HCV-infected livers as compared to the control were detected. Within both groups, expression of the IGF-1A mRNA isoform significantly prevailed over expressions of B and C isoforms. Expression of P1 mRNA was higher than that of P2 only in CH-C. Very high positive correlations were detected between reciprocal expressions of IGF-1 mRNA isoforms P1 and P2 (r = 0.876). Expression of P1 and P2 mRNA correlated with IGF-1A mRNA (r = 0.891; r = 0.821, respectively), with IGF-1B mRNA (r = 0.854; r = 0.813, respectively), and with IGF-1C mRNA (r = 0.839; r = 0.741, respectively). Expression of IGF-1A mRNA significantly correlated with isoform B and C mRNA (r = 0.956; r = 0.869, respectively), and B with C isoforms (r = 0.868) (P < 0.05 in all cases). Lower expression of IGF-1A and B transcripts was noted in the more advanced liver grading (G2) as compared to G1. Multiple negative correlations were detected between expression of various IGF-1 transcripts and clinical data (e.g., alpha fetoprotein, HCV RNA, steatosis, grading, and staging). Expression of IGF-1R mRNA manifested positive correlation with grading and HCV-RNA.

CONCLUSION: Differences in quantitative expression of IGF-1 mRNA isoforms in HCV-infected livers, as compared to the control, suggest that HCV may induce alteration of IGF-1 splicing profile.

Keywords: Chronic hepatitis C, Insulin-like growth factor-1 receptor, Insulin-like growth factor-1 mRNA isoforms, Quantitative polymerase chain reaction

Core tip: Hepatitis C virus (HCV) may induce alteration of insulin-like growth factor (IGF)-1 splicing profile. A quantitative polymerase chain reaction analysis confirmed higher relative expression of total IGF-1 mRNA and of IGF-1 mRNAs isoforms P1, A, and C in HCV-infected livers as compared to the control. An increase in inflammatory activity (grading) of HCV-infected livers was linked to decreased IGF-1 mRNA expression, an altered profile of mRNA isoforms, and to an increase in IGF-1R mRNA expression. Decreased expression level of IGF-1 mRNA isoforms and an increased liver expression of IGF-1R mRNA were associated with indicators of liver damage (e.g., grading, staging, steatosis, and liver serum enzyme activity), and may be of prognostic significance.