miRNA-324, a potential therapeutic target for paracetamol-induced liver injury

miRNA-324, a potential therapeutic target for paracetamol-induced liver injury

Hong Min Wu, Sang Geon Kim

College of Pharmacy and Research Institute of Pharmaceutical Sciences, Seoul National University, Seoul, Korea

Correspondence to: Sang Geon Kim, PhD. College of Pharmacy, Seoul National University, Sillim-dong, Kwanak-gu, Seoul 151-742, Korea. Email: sgk@snu.ac.kr.

Received: 01 September 2016; Accepted: 12 October 2016; Published: 25 October 2016.

doi: 10.21037/sci.2016.10.04

Paracetamol is one of the most widely used medications for relieving pain and fever. When taken in the therapeutic doses, paracetamol is predominantly metabolized in the liver via conjugation reaction by phase II drug metabolizing enzymes such as sulfotransferases and glucuronyl transferases, and is removed from the body without liver damage (1). However, when paracetamol is taken in excessive doses, it is bioactivated by phase I enzymes (e.g., CYP3A4 and CYP2E1) to generate a toxic intermediate N-acetyl-p-benzoquinone imine (NAPQI). Rapid generation of NAPQI can lead to the depletion of intrahepatic glutathione and result in hepatocyte death and liver injury (2). Thus, hepatotoxicity elicited by paracetamol overdose is the most common cause of poisoning-related deaths (3). In other studies, overdose of paracetamol accounted for the highest proportion of cases of acute liver failure in many developed countries, resulting in death or liver transplantation (4,5). Currently, N-acetylcysteine (NAC) is the mainstay strategy in treating hepatotoxicity following paracetamol overdose. However, oral and intravenous NAC treatment has limitations because of adverse effects (6,7). Thus, identifying new therapeutic targets would be of help for clinical remedy of paracetamol overdose-related liver injury.

Numerous studies have been conducted on the expression and function of drug-metabolizing enzymes (DMEs), and the information was applied for better understanding and prediction of drug responses in patients (8). Moreover, identification of novel regulators of DMEs is critical to supply more information for clinical applications. In a recent issue of Stem Cells Transl Med, Hay and colleagues have identified that inhibition of a novel noncoding RNA can reduce paracetamol-induced liver toxicity (9). The authors demonstrated that miRNA-324-5p regulates phase II drug metabolism and that the inhibitor of miRNA-324-5p can promote nontoxic metabolism of paracetamol. This finding has the potential to help clinical research in identifying future therapeutic strategy for paracetamol-induced toxicity.

To examine hepatocyte biology in vitro, immortalized human hepatocytes have been developed since they are the most physiologically relevant to human liver in drug response (10). However, some limitations such as karyotypic instability and poor function exist in the derived cell lines, thus preventing their further application (10). Previously, Hay et al. have used human embryonic stem cells (hESCs) to generate human hepatocyte-like cells (hHLCs) using a serum-free-based procedure (11), which has been proved to be scalable and more primary in nature and is promising in modeling human drug metabolism and toxicity. In the current research, according to the established methodology, hESCs were differentiated to hHLCs through 18 days of culture, as indicated by the appropriate cell morphology, gene expression, and appreciable levels of metabolic function (9). Hay et al. compared hHLCs with adult human hepatocytes and confirmed the gene expression profiles of phase I, II and II drug-metabolism (9). Thus, use of hESCs and hHLCs has become a useful in vitro model in studying and understanding the genotype-phenotype relationship in the human population.

The miRNAs post-transcriptionally control protein expression by binding to the 3’-UTRs of target mRNAs, and thereby lead to translational inhibition or mRNA degradation (12). In many laboratories, miRNAs have been shown to affect DMEs related with paracetamol metabolism (13-19). For example, miR-27b and miR-378 regulate paracetamol oxidation enzyme CYP3A4 and CYP2E1, respectively (13,14). Research on miRNAs regulation of phase II enzymes was limited to SULT1A1 (paracetamol sulfation enzyme), GSTP1 (NAPQI conjugation enzyme) and UGT1A (paracetamol glucuronidation enzyme) (15-17). Other studies have focused on miRNA regulation of paracetamol transporter-related ATP Binding Cassette (ABC) transporters (e.g., ABCC4 and ABCG2) (18,19). In the current study, Hay and colleagues enlarged our understanding on the information of miRNA that can regulate paracetamol-metabolizing DMEs by identifying a novel miRNA, miRNA-324-5p, in the regulation of SULT2A1 (9). They elucidated a supportive role of antagomir 324 (miR-324 inhibitor) in the improvement of hepatocyte survival in the context of acute injury and patient recovery after paracetamol overdose. From a standpoint of molecular mechanisms responsible for hepatotoxicity following paracetamol overdose, this study broadens our understanding on miRNA-based regulation of phase II drug metabolizing enzymes and may offer a new and attractive strategy for the treatment of liver injury induced by paracetamol overdose.


Funding: This editorial is supported by the Bio and Medical Technology Development Program of the NRF funded by the Korean government, MSIP (2015M3A9B6074045) and by Korea Institute of Oriental Medicine (K16820).


Provenance: This is a Guest Editorial commissioned by Editor-in-Chief Zhizhuang Joe Zhao (Pathology Graduate Program, University of Oklahoma Health Sciences Center, Oklahoma City, USA).

Conflicts of Interest: The authors have no conflicts of interest to declare.

Comment on: Szkolnicka D, Lucendo-Villarin B, Moore JK, et al. Reducing Hepatocyte Injury and Necrosis in Response to Paracetamol Using Noncoding RNAs. Stem Cells Transl Med 2016;5:764-72.


  1. Chun LJ, Tong MJ, Busuttil RW, et al. Acetaminophen hepatotoxicity and acute liver failure. J Clin Gastroenterol 2009;43:342-9. [Crossref] [PubMed]
  2. Makin AJ, Wendon J, Williams R. A 7-year experience of severe acetaminophen-induced hepatotoxicity (1987-1993). Gastroenterology 1995;109:1907-16. [Crossref] [PubMed]
  3. Mowry JB, Spyker DA, Brooks DE, et al. 2014 Annual Report of the American Association of Poison Control Centers' National Poison Data System (NPDS): 32nd Annual Report. Clin Toxicol (Phila) 2015;53:962-1147. [Crossref] [PubMed]
  4. Larsen FS, Wendon J. Understanding paracetamol-induced liver failure. Intensive Care Med 2014;40:888-90. [Crossref] [PubMed]
  5. Yoon E, Babar A, Choudhary M, et al. Acetaminophen-induced hepatotoxicity: a comprehensive update. J Clin Transl Hepatol 2016;4:131-42. [PubMed]
  6. Smilkstein MJ, Knapp GL, Kulig KW, et al. Efficacy of oral N-acetylcysteine in the treatment of acetaminophen overdose. Analysis of the national multicenter study (1976 to 1985). N Engl J Med 1988;319:1557-62. [Crossref] [PubMed]
  7. Pakravan N, Waring WS, Sharma S, et al. Risk factors and mechanisms of anaphylactoid reactions to acetylcysteine in acetaminophen overdose. Clin Toxicol (Phila) 2008;46:697-702. [Crossref] [PubMed]
  8. Ikemura K, Iwamoto T, Okuda M. MicroRNAs as regulators of drug transporters, drug-metabolizing enzymes, and tight junctions: implication for intestinal barrier function. Pharmacol Ther 2014;143:217-24. [Crossref] [PubMed]
  9. Szkolnicka D, Lucendo-Villarin B, Moore JK, et al. Reducing hepatocyte injury and necrosis in response to paracetamol using noncoding RNAs. Stem Cells Transl Med 2016;5:764-72. [Crossref] [PubMed]
  10. Delgado JP, Parouchev A, Allain JE, et al. Long-term controlled immortalization of a primate hepatic progenitor cell line after Simian virus 40 T-Antigen gene transfer. Oncogene 2005;24:541-51. [Crossref] [PubMed]
  11. Szkolnicka D, Farnworth SL, Lucendo-Villarin B, et al. Deriving functional hepatocytes from pluripotent stem cells. Curr Protoc Stem Cell Biol 2014;30:1G.5.1-12.
  12. Carthew RW, Sontheimer EJ. Origins and mechanisms of miRNAs and siRNAs. Cell 2009;136:642-55. [Crossref] [PubMed]
  13. Pan YZ, Gao W, Yu AM. MicroRNAs regulate CYP3A4 expression via direct and indirect targeting. Drug Metab Dispos 2009;37:2112-7. [Crossref] [PubMed]
  14. Mohri T, Nakajima M, Fukami T, et al. Human CYP2E1 is regulated by miR-378. Biochem Pharmacol 2010;79:1045-52. [Crossref] [PubMed]
  15. Yu X, Dhakal IB, Beggs M, et al. Functional genetic variants in the 3'-untranslated region of sulfotransferase isoform 1A1 (SULT1A1) and their effect on enzymatic activity. Toxicol Sci 2010;118:391-403. [Crossref] [PubMed]
  16. Zhang X, Zhu J, Xing R, et al. miR-513a-3p sensitizes human lung adenocarcinoma cells to chemotherapy by targeting GSTP1. Lung Cancer 2012;77:488-94. [Crossref] [PubMed]
  17. Dluzen DF, Sun D, Salzberg AC, et al. Regulation of UDP-glucuronosyltransferase 1A1 expression and activity by microRNA 491-3p. J Pharmacol Exp Ther 2014;348:465-77. [Crossref] [PubMed]
  18. Borel F, Han R, Visser A, et al. Adenosine triphosphate-binding cassette transporter genes up-regulation in untreated hepatocellular carcinoma is mediated by cellular microRNAs. Hepatology 2012;55:821-32. [Crossref] [PubMed]
  19. Padmanabhan R, Chen KG, Gillet JP, et al. Regulation and expression of the ATP-binding cassette transporter ABCG2 in human embryonic stem cells. Stem Cells 2012;30:2175-87. [Crossref] [PubMed]
doi: 10.21037/sci.2016.10.04
Cite this article as: Wu HM, Kim SG. miRNA-324, a potential therapeutic target for paracetamol-induced liver injury. Stem Cell Investig 2016;3:67.