Toxicity of Carboxylic Acid-Containing Drugs: The Role of Acyl Migration and CoA Conjugation Investigated

Abstract

Many carboxylic acid-containing drugs are associated with idiosyncratic drug toxicity (IDT), which may be caused by reactive acyl glucuronide metabolites. The rate of acyl migration has been earlier suggested as a predictor of acyl glucuronide reactivity. Additionally, acyl Coenzyme A (CoA) conjugates are known to be reactive. Here, 13 drugs with a carboxylic acid moiety were incubated with human liver microsomes to produce acyl glucuronide conjugates for the determination of acyl glucuronide half-lives by acyl migration and with HepaRG cells to monitor the formation of acyl CoA conjugates, their further conjugate metabolites, and trans-acylation products with glutathione. Additionally, in vitro cytotoxicity and mitochondrial toxicity experiments were performed with HepaRG cells to compare the predictability of toxicity. Clearly, longer acyl glucuronide half-lives were observed for safe drugs compared to drugs that can cause IDT. Correlation between half-lives and toxicity classification increased when "relative half-lives," taking into account the formation of isomeric AG-forms due to acyl migration and eliminating the effect of hydrolysis, were used instead of plain disappearance of the initial 1-O-β-AG-form. Correlation was improved further when a daily dose of the drug was taken into account. CoA and related conjugates were detected primarily for the drugs that have the capability to cause IDT, although some exceptions to this were observed. Cytotoxicity and mitochondrial toxicity did not correlate to drug safety. On the basis of the results, the short relative half-life of the acyl glucuronide (high acyl migration rate), high daily dose and detection of acyl CoA conjugates, or further metabolites derived from acyl CoA together seem to indicate that carboxylic acid-containing drugs have a higher probability to cause drug-induced liver injury (DILI).

Kinetic modelling of acyl glucuronide and glucoside reactivity and development of structure–property relationships

“…The reactivity of the acyl glucuronide conjugates of drugs and other xenobiotics has been studied extensively on account of their potential hepatotoxicity [1][2][3][4] (as have the corresponding S-acyl-CoA thioesters which are also chemically reactive). [5][6][7][8] Acyl glucuronides are formed through the conjugation of α-Dglucuronic acid with the carboxylic acid group of a xenobiotic in the presence of membrane-bound UDP-glucuronosyltransferase (UGT) enzymes. The 1-β-O-acyl glucuronides that form can undergo a cascade of spontaneous chemical reactions including acyl migration, anomerisation, and hydrolysis to produce seven further positional anomers: 1-α, 2-α, 2-β, 3-α, 3β, 4-α, 4-β, the aglycone, and both αand β-glucuronic acid.…”

PON1 increases cellular DNA damage by lactone substrates

“…This might argue that the DNA damaging moiety is the intact lactone, and indeed a number of different lactones including AL have been shown to react with the DNA surrogate, 4-(p-nitrobenzyl)pyridine (Manso et al 2005;Fernández-Rodríguez et al 2007). However, lactones are hydrolysed by PON1 to the corresponding hydroxyl acid (Billecke et al 2000;Teiber et al 2003) and acyl glucuronides of carboxylic acid containing agents have been reported to be toxic and react with cellular macromolecules (Lassila et al 2015;Van Vleet et al 2017). The exact nature of the DNA damaging agent is thus currently unclear.…”

Metabolite profiling of carbamazepine and ibuprofen in Solea senegalensis bile using high-resolution mass spectrometry

“…In contrast to CBZ where the glucuronidation of the (di)hydroxylated metabolites involved the formation of an ether bond, transfer of glucuronic acid to the carboxyl group IBU molecule produced the acyl glucuronide (M382), i.e., an ester bond. The observation of a partially resolved peak cluster of M382 in the extracted ion chromatogram (m/z 381.1558) instead of a single peak with a defined retention time (see ESM Table S1) is typical of acyl glucuronides because they are subject to acyl migration yielding positional isomers [26]. Taking advantage of this characteristic behavior, the visual inspection of the peak profiles allowed to easily discriminate between the hydroxyglucuronides bearing the glucuronic acid on the OH group and the isobaric acyl glucuronides.…”