Basic Study
Copyright ©The Author(s) 2016. Published by Baishideng Publishing Group Inc. All rights reserved.
World J Gastroenterol. Dec 21, 2016; 22(47): 10341-10352
Published online Dec 21, 2016. doi: 10.3748/wjg.v22.i47.10341
Anti-viral role of toll like receptor 4 in hepatitis B virus infection: An in vitro study
Dipanwita Das, Neelakshi Sarkar, Isha Sengupta, Ananya Pal, Debraj Saha, Manikankana Bandopadhyay, Chandrima Das, Jimmy Narayan, Shivram Prasad Singh, Runu Chakravarty
Dipanwita Das, Neelakshi Sarkar, Ananya Pal, Debraj Saha, Manikankana Bandopadhyay, Runu Chakravarty, ICMR Virus Unit, Kolkata, ID and BG Hospital Campus, Kolkata 700010, India
Isha Sengupta, Chandrima Das, Biophysics and Structural Genomics Division, Saha Institute of Nuclear Physics, Kolkata 700064, India
Jimmy Narayan, Shivram Prasad Singh, Department of Gastroenterology, SCB Medical College, Cuttack 753007, India
Shivram Prasad Singh, Kalinga Gastroenterology Foundation, Beam Diagnostics Premises, Cuttack 753001, India
Author contributions: Das D, Sarkar N, Das C and Chakravarty R conceived and designed the experiments; Das D, Sarkar N, Sengupta I and Pal A performed the experiments; Das D, Sarkar N, Sengupta I, Das C, Narayan J, Singh SP and Chakravarty R analyzed the data; Das D, Sarkar N, Pal A, Saha D, Bandopadhyay M, Das C and Chakravarty R contributed reagents/materials/analysis tools; Das D, Sarkar N, Sengupta I, Pal A, Saha D, Bandopadhyay M, Das C and Chakravarty R wrote the paper.
Supported by the Indian Council of Medical Research (ICMR) intramural project; Das C acknowledges the financial support from Biomolecular Assembly, Recognition and Dynamics (BARD) project (Grant 12-R &D- SIN-5.04-0103) from Department of Atomic Energy (DAE), Government of India and Ramalingaswami Fellowship, Department of Biotechnology, Government of India.
Institutional review board statement: Signed informed consent was obtained from patients and the study was approved by the institutional ethical committee of Kalinga Gastroenterology Foundation.
Conflict-of-interest statement: The authors declare no conflict of interest.
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: Dr. Runu Chakravarty, ICMR Virus Unit, Kolkata, ID and BG Hospital Campus, GB 4, Kolkata 700010, India. runugc@gmail.com
Telephone: +91-33-23537425 Fax: +91-33-23537424
Received: June 26, 2016
Peer-review started: June 27, 2016
First decision: August 29, 2016
Revised: October 1, 2016
Accepted: November 16, 2016
Article in press: November 16, 2016
Published online: December 21, 2016
Processing time: 176 Days and 19.8 Hours
Abstract
AIM

Toll like receptors plays a significant anti-viral role in different infections. The aim of this study was to look into the role of toll like receptor 4 (TLR4) in hepatitis B virus (HBV) infection.

METHODS

Real time PCR was used to analyze the transcription of TLR4 signaling molecules, cell cycle regulators and HBV DNA viral load after triggering the HepG2.2.15 cells with TLR4 specific ligand. Nuclear factor (NF)-κB translocation on TLR4 activation was analyzed using microscopic techniques. Protein and cell cycle analysis was done using Western Blot and FACS respectively.

RESULTS

The present study shows that TLR4 activation represses HBV infection. As a result of HBV suppression, there are several changes in host factors which include partial release in G1/S cell cycle arrest and changes in host epigenetic marks. Finally, it was observed that anti-viral action of TLR4 takes place through the NF-κB pathway.

CONCLUSION

The study shows that TLR4 activation in HBV infection brings about changes in hepatocyte microenvironment and can be used for developing a promising therapeutic target in future.

Keywords: Hepatitis B virus; Toll like receptor 4; Cell cycle; Epigenetic marks; Innate immune response

Core tip: The study delves into the role of toll like receptor 4 (TLR4) in hepatitis B virus (HBV) infection. Inciting TLR4 brings about drastic changes in viral and host responses in hepatocyte niche. Stimulating TLR4 represses viral replication and alters important host gene expression. Virus induced G1/S cell cycle arrest is partially released on viral elimination which is corroborated with the expression of chief cell cycle regulators. Further, we have observed activation of epigenetic signatures H3K9Ac/H3K18Ac, on viral suppression post TLR4 activation. Thus, this work is important in perspective of the role of TLR4 during HBV infection in hepatocyte microenvironment.