Small RNA sequencing reveals new mode of action and potential biomarkers for the mycotoxin Zearalenone

Purpose: The mycotoxin zearalenone (ZEN) poses a risk to animal health because of its estrogenic effects. Diagnosis of ZEN-induced disorders in animal production remains challenging due to the lack of appropriate non-invasive biomarkers. Thus, we combined untargeted and targeted transcriptomics approaches to investigate the effects of ZEN on the microRNA expression in porcine uterus, jejunum and serum. Methods: twenty-four piglets received either uncontaminated feed (Control) or feed containing 0.17 mg/kg ZEN (ZEN low), 1.46 mg/kg ZEN (ZEN medium) and 4.58 mg/kg ZEN (ZEN high) for 28 days. microRNA from uterus and jejunum tissues were profiled by next-generation small RNA sequencing. Serum microRNA expression was analyzed by RT-qPCR analysis. Results: the microRNA expression in the jejunum remained unaffected, while significant changes in the uterine microRNA profile were observed. Importantly, 14 microRNAs were commonly and in a dose-dependent manner affected in both the ZEN medium and ZEN high group, including microRNAs from the miR-503 cluster. Although the effects in the serum were less pronounced, the receiver operating characteristic analysis revealed that several microRNA ratios were able to discriminate properly between non-exposed and ZEN-exposed pigs (e.g. ssc-miR-135a-5p/ssc-miR-432-5p, ssc-miR-542-3p/ssc-miR-493-3p). Conclusions: This work sheds some new light on the molecular mechanisms of ZEN, and fosters biomarker discovery. Uterus and jejunum microRNA profiles at 28 days post weaned piglets. For each tissue, 6 biological replicates (= 6 pigs) from Control, 4 from ZEN low, 4 from ZEN medium, and 4 from ZEN high were used for library preparation. The final multiplexed (n=18) libraries were sequenced on a NextSeq 500