Identification of microRNAs Implicated in Modulating Senecionine-Induced Liver Toxicity in HepaRG Cells.

Albert Braeuning,Stefanie Hessel-Pras,Anne-Margarethe Enge,Heike Sprenger

doi:10.3390/foods11040532

Albert Braeuning, Stefanie Hessel-Pras + Show 2 more

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https://doi.org/10.3390/foods11040532

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Abstract

1,2-unsaturated Pyrrolizidine Alkaloids (PAs) are secondary plant metabolites that occur as food contaminants. Upon consumption, they can cause severe liver damage. PAs have been shown to induce apoptosis, to have cytotoxic and genotoxic effects, and to impair bile acid homeostasis in the human hepatoma cell line HepaRG. The major mode of action of PAs is DNA- and protein-adduct formation. Beyond that, nuclear receptor activation has only been observed for one receptor and two PAs, yielding the possibility that other cellular mediators are involved in PA-mediated toxicity. Here, the mode of action of Senecionine (Sc), a prominent and ubiquitous representative of hepatotoxic PAs, was investigated by analyzing 7 hepatic microRNAs (miRNAs) in HepaRG cells. Ultimately, 11 target genes that were predicted with Ingenuity Pathway Analysis software (IPA) were found to be significantly downregulated, while their assigned miRNAs showed significant upregulation of gene expression. According to IPA, these targets are positively correlated with apoptosis and cellular death and are involved in diseases such as hepatocellular carcinoma. Subsequent antagomiR-inhibition analysis revealed a significant correlation between PA-induced miRNA-4434 induction and P21-Activated Kinase-1 (PAK1) downregulation. PAK1 downregulation is usually associated with cell cycle arrest, suggesting a new function of Sc-mediated toxicity in human liver cells.

Highlights

Pyrrolizidine alkaloids are the most common natural toxins with over 660 different chemical structures
The miRNA expression profile in HepaRG cells was analyzed with a customized liver-specific miCURY Locked Nucleic Acids (LNA) Array covering 84 miRNAs
Compared to the control group, the number of deregulated miRNAs above 1 log2 Fold Change (FC) or below 1 log2 FC tended to be highest at 250 μM after 8 h and at 35 μM after 24 h, respectively

Summary

Introduction

Pyrrolizidine alkaloids are the most common natural toxins with over 660 different chemical structures. They are present in more than 6000 plant species worldwide and can occur as contaminants in food and feed, posing a possible health risk for humans and livestock [1]. They can be found in products such as tea, honey, culinary herbs, dietary supplements or herbal preparations such as traditional medicine [2,3,4,5]. It is recommended to apply the ALARA principle (As Low As Reasonably Achievable) to prevent unnecessary exposure [6]

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