Comparison of DNA and RNA Adduct Formation: Significantly Higher Levels of RNA than DNA Modifications in the Internal Organs of Aristolochic Acid-Dosed Rats

Abstract

Prolonged exposure to aristolochic acid (AA)contaminated slimming drugs and food is believed to be associated with the development of endemic nephropathy in Belgian women and in farmers living alongside the Danube River. Decades of research has revealed the pathophysiology of carcinogenesis of AA,and the molecular mechanisms underlying renal interstitial fibrosis remain unclear. We hypothesized that RNA modification may have contributed to the observed toxicity of AA. Thus, a highly sensitive and selective ultra-high performance liquid chromatography-coupled tandem mass spectrometric method was developed to quantify RNA-AA adducts in target and nontarget organs of AA-dosed rats. The results revealed, for the first time, that AA forms RNA adducts in vitro and in vivo. Comparative studies on DNA revealed that RNA is modified by AA at frequencies approximately 6-fold higher than that of DNA in both kidney and liver tissue in AA-dosed rats. Results also demonstrated that guanosine is modified by AA at frequencies significantly higher than that of adenosine, 2-deoxyadenosine, and 2-deoxyguanosinein both organs of the AA-dosed. This finding suggests that guanosine is a major target for AA and that guanosine adducts of AA might be critical lesions in the pathophysiology of AA-induced toxicity. It is anticipated that the results of our study may open up a new area of investigating the nephrotoxicity and/or carcinogenicity by quantifying RNA adducts using the UPLC-MS/MS technique of high sensitivity and selectivity.

An Integrated View of Aristolochic Acid Nephropathy: Update of the Literature

“…In this regard, Leung and Chan [108] first described that AA forms covalently bonded RNA adducts both in vitro and in vivo. Particularly, AA have been found to modify guanosine at significantly higher frequencies than adenosine suggesting that guanosine is a major target of AA and that guanosine adducts might constitute a critical factor in AA-induced nephrotoxicity and carcinogenicity.…”

Systematic Overview of Aristolochic Acids: Nephrotoxicity, Carcinogenicity, and Underlying Mechanisms

“…In animal studies, A→T transversions were observed in the activating positions in H- ras of rats treated with AAs (Wang et al, 2011). Further, RNAs modified by AAs were at much higher frequencies than DNA (Leung and Chan, 2015).…”

TP53 mutations in p53-negative dysplastic urothelial cells from Belgian AAN patients: New evidence for aristolochic acid-induced molecular pathogenesis and carcinogenesis

“…Compared to adenine adducts, guanine adducts have been shown to be weakly miscoding, but whether dAMP can be misincorporated in vivo opposite dG-AAI when people are accidentally exposed to high doses of AA remains to be further investigated. It is worth mentioning that the alteration of guanosine by AA at a frequency significantly higher than with adenosine has been reported in kidney and liver tissues in AA-exposed rats suggesting that guanosine adducts with AA might play a more important role than hitherto believed in AA-induced toxicity [27]. Of note, A > G transitions as found in this Belgian series of AA patients, are not an unusual finding in AA-unrelated UC nor in other cancers [28].…”