Molecular mechanism of ochratoxin A and ochratoxin A together with citrinin on human renal cells

赭曲霉毒素A和桔霉素是霉菌在食物和饲料中生长的代谢产物。通常，在食品中发现它们一起存在，由于共同暴露而产生风险。我们可以证明，在纳摩尔范围内暴露于OTA导致WISP1(WNT1信号通路蛋白1)的RNA表达显著增加。除WISP1外，与纤维化或炎症相关的其他基因的表达也升高。初步实验表明，OTA上调的WISP1-RNA不编码蛋白质，但可以与抗纤维化的miR-29b结合，从而干扰其调节功能。这个新的替代WISP1转录本还包含其他miRNAs的假定结合位点，它们与OTA毒性的相关性仍有待确定。此外，其他OTA调控基因的重要性仍有待确定。OTB是一种不含氯部分的OTA类似物，对WISP1-RNA的替代表达没有影响。因此，表征OTA分子的这个官能团和其他官能团的作用是非常诱人和机械相关的。通过氯与其他卤素的交换和苯丙氨酸与其他氨基酸的交换，我们能够确定这些基团对细胞存活、纤维化事件和基因表达的影响。OTA和桔霉素一起存在于食品中。因此，相互影响细胞的命运是可以想象的。单独一种物质(OTA或桔霉素)的有害影响可能会因额外的压力而加剧，例如由于自由基形成增加而造成的。我们能够通过测量原代培养的人肾细胞的细胞存活率、纤维化改变或基因表达异常来确定OTA和桔霉素或OTA和其他内源性应激源共同暴露的影响，作为增加自由基形成的影响。因此，有必要确定(I)WISP1-RNA(和其他OTA调节基因)的作用以及鉴定可能干扰OTA毒性的miRNAs，(Ii)使用OTA类似物确定OTA分子官能团的重要性，并确定(Iii)共同暴露于这两种真菌毒素以及内源性细胞应激所产生的潜在风险。这些研究将主要使用原代培养的人肾细胞进行。

Ochratoxin A and citrinin are metabolites of mould fungi growing on food and feed. Often they are found together in foodstuff generating a risk due to co-exposure. We could show that exposure to OTA in the nanomolar range led to a marked increase of the RNA expression of WISP1 (Wnt1 signaling pathway protein 1). Besides WISP1 also the expression of other genes involved in fibrosis or inflammation was elevated. First experiments show that the OTA-upregulated WISP1-RNA does not code for a protein but can bind the anti-fibrotic miR-29b, thereby disturbing its regulatory function. This new alternative WISP1 transcript contains putative binding sites for other miRNAs also and their relatedness to OTA toxicity remains to be determined. Additionally, the importance of the other OTA-regulated genes remains to be deter-mined.OTB, an OTA analogon without the chloride moiety, has no effect on the alternative WISP1-RNA expression. Therefore, it is extremely tantalizing and mechanistically relevant to characterize the role of this and other functional groups of the OTA molecule. By exchanging the chloride against other halogens and the phenylalanine against other amino acids, we are able to determine the impact of these groups for cell survival, fibrotic events and gene expression.OTA and citrinin can be found together in foodstuff. Therefore, a mutual influence on cell fate is conceivable. The harmful effects of one substance (OTA or citrinin) alone may be aggravated by additional stress, as caused by e.g. increased radical formation. We are able to determine the effects of a co-exposure of OTA and citrinin or OTA and other endogenously generated stressors as increased radical formation by measuring cell survival, fibrotic alterations, or dysregulated gene expression in human renal cells in primary culture.In summary therefore, it is necessary to determine(i) the role of the WISP1-RNA (and the other OTA-regulated genes) as well as to identify miRNAs which may interfere in OTA toxicity,(ii) the importance of functional groups of the OTA molecule using OTA analoga and to determine(iii) the potential risk emanating from co-exposure to the two mycotoxins together with endogenously generated cell stress.These investigations will be done using human renal cells mostly in primary culture.