Proceedings of The Physiological Society

Europhysiology 2018 (London, UK) (2018) Proc Physiol Soc 41, PCA254

Poster Communications

The nephropathic mycotoxin Ochratoxin A leads to cell cycle arrest in human kidney cell lines

V. Dubourg1, M. Kopf1, G. Schwerdt1, M. Gekle1

1. Martin-Luther-University Halle-Wittenberg, Julius-Bernstein-Institute for Physiology, Halle (Saale), Germany.

Filtration, reabsorption and secretion are the three essential processes for renal functions. However, this physiological system turns out to be critical in the elimination process of some harmful substances. The latter include Ochratoxin A (OTA) [1], a mycotoxin produced by Aspergillus or Penicillium species that is commonly found in foodstuff. Various effects have been attributed to this substance but its main target remains the kidney due to the filtration-reabsorption-secretion system that delays its excretion and leads to its accumulation in tubular cells. The underlying mechanisms by which OTA affects kidney cells remain nonetheless mainly unknown. In the present study, we were therefore interested in identifying putative key drivers in OTA-induced nephropathies. To do so, RNA-sequencing was carried out on human kidney cell lines (HEK-293T and HK-2) that were exposed to low concentrations (nanomolar range) of OTA for 48 hours. Differential expression and pathway enrichment analyses were performed. Moreover, Propidium Iodide (PI)-staining was used for cell cycle analysis by Flow Cytometry and the level of expression of CDKN1A/p21 was further investigated by RT-qPCR and Western Blot. Our analysis revealed that the expression of several thousands of genes was influenced by OTA-exposure in human kidney cell lines (with |log2 Fold Change| > 1, FDR 0.01). These changes in the transcriptome were associated with the regulation of pathways related to DNA damage, protein metabolism and cell cycle regulation. In order to understand the impact of OTA on the latter, cell cycle analysis was additionally performed. The results highlighted a cell cycle arrest in kidney cell lines induced by OTA at physiological concentrations (< 100nM). We, moreover, observed that CDKN1A/p21, a key regulator of the G1/S check-point, was up-regulated under the influence of OTA. The data obtained for this study thus showed that exposure to OTA leads to global changes in the transcriptome of kidney cell lines, including for genes involved in the regulation of the cell cycle. More precisely, our results suggest that the OTA-induced nephropathies may be due to an arrest of the cell cycle. We propose that the OTA-regulated protein CDKN1A/p21 contributes to this effect.

Where applicable, experiments conform with Society ethical requirements