Integration of Transcriptomic and Metabolomic Data to Compare the Hepatotoxicity of Neonatal and Adult Mice Exposed to Aristolochic Acid I

Disruption of local circadian clocks in aristolochic acid-induced nephropathy in mice

BACKGROUND

Aristolochic acid I (AAI), an emerging biogenic contaminant widely present in Aristolochic plants, has been implicated in the progression of tubulointerstitial disease, known as aristolochic acid nephropathy (AAN). The circadian clock, a vital regulator of organ homeostasis, is susceptible to external chemical cues, including toxins. However, the reciprocal interactions between AAI and the circadian clock remain unexplored.

METHODS

We initially assessed sex- and time-dependent nephropathy and behavioral responses in C57BL/6J mice exposed to AAI. Subsequently, we evaluated changes in the expression of circadian clock genes following treatment with AAI or its bioactive metabolite, aristolactam I, using real-time quantitative PCR and immunoblotting in renal tissues and cells. Additionally, real-time reporter assays were conducted on kidney explants from PER2::Luc knock-in reporter mice and Per2-dLuc/Bmal1-dLuc reporter cell lines. To further elucidate the regulatory role of circadian clocks in AAI-induced nephropathy, mice with global or kidney-specific knockout of Bmal1, as well as mice subjected to experimental jetlag, were utilized.

RESULTS

Our findings revealed a sex-dependent nephrotoxicity of AAI, with males exhibiting greater vulnerability. AAI-induced nephropathy was accompanied by impaired spatial cognitive function, disruptions in free-running locomotor activity, altered renal expression of multiple core clock genes, and disturbances in the circadian rhythm of renal PER2::Luc activity. Notably, kidney-specific ablation of the core clock gene Bmal1 significantly exacerbated renal injury and inflammation, whereas disruptions to the central clock, either genetically (through conventional knockout of Bmal1) or environmentally (mimicking jetlag), had minimal effects on AAI nephrotoxicity. Furthermore, both AAI and its bioactive metabolite aristolactam I demonstrated the ability to disrupt circadian clocks in human osteosarcoma cells (U2OS) and mouse renal tubular epithelial cells (mRTEC).

CONCLUSION

Collectively, these findings highlight the detrimental impact of aristolochic acids on local renal circadian clocks, ultimately exacerbating kidney damage. This study provides novel insights into the molecular mechanisms underlying AAI nephrotoxicity, potentially opening avenues for therapeutic interventions aimed at modulating the renal circadian clock to treat AAN.

Long-term oral administration of Kelisha capsule does not cause hepatorenal toxicity in rats

ETHNOPHARMACOLOGICAL RELEVANCE

Kelisha capsules (KLS) are often used to treat acute diarrhoea, bacillary dysentery, heat stroke, and other diseases. One of its components, Asarum, contains aristolochic acid I which is both nephrotoxic and carcinogenic. However, the aristolochic acid (AA) content in KLS and its toxicity remain unclear.

AIM OF THE STUDY

The aims of this study were to quantitatively determine the contents of five aristolochic acid analogues (AAAs) in Asarum and KLS, and systematically evaluate the in vivo toxicity of KLS in rats.

MATERIALS AND METHODS

Ultra-performance liquid chromatography-tandem mass spectrometry (UPLC-MS/MS) was used to determine the content of the five AAAs in Asarum and KLS. Sprague-Dawley rats were administered KLS at 0, 0.75, 1.5, and 3.0 g/kg respectively, and then sacrificed after 4 weeks of administration or after an additional 2 weeks of recovery. The endpoints assessed included body weight measurements, serum biochemistry and haematology indices, and clinical and histopathological observations.

RESULTS

The AAAs content in Asarum sieboldii Miq. (HB-ESBJ) were much lower than those of the other Asarums. The contents of AA I, AA IVa, and aristolactam I in KLS were in the ranges of 0.03-0.06 μg/g, 1.89-2.16 μg/g, and 0.55-1.60 μg/g, respectively, whereas AA II and AA IIIa were not detected. None of the rats showed symptoms of toxic reactions and KLS was well tolerated throughout the study. Compared to the control group, the activated partial thromboplastin time values of rats in the 1.5 and 3.0 g/kg groups significantly reduced after administration (P < 0.05). In addition, the serum triglycerides of male rats in the 0.75 and 1.5 g/kg groups after administration, and the 0.75, 1.5, 3.0 g/kg groups after recovery were significantly decreased (P < 0.01 or P < 0.001). No significant drug-related toxicological changes were observed in other serum biochemical indices, haematology, or histopathology.

CONCLUSIONS

The AA I content in KLS met the limit requirements (<0.001%) of the Chinese Pharmacopoeia. Therefore, it is safe to use KLS in the short-term. However, for safety considerations, attention should be paid to the effects of long-term KLS administration on coagulation function and triglyceride metabolism.

Unveiling correlations between aristolochic acids and liver cancer: spatiotemporal heterogeneity phenomenon

Aristolochic acids are a class of naturally occurring compounds in Aristolochiaceae that have similar structural skeletons and chemical properties. Exposure to aristolochic acids is a risk factor for severe kidney disease and urinary system cancer. However, the carcinogenicity of aristolochic acids to the liver, which is the main site of aristolochic acid metabolism, is unclear. Although the characteristic fingerprint of aristolochic acid-induced mutations has been detected in the liver and aristolochic acids are known to be hepatotoxic, whether aristolochic acids can directly cause liver cancer is yet to be verified. This review summarizes the findings of long-term carcinogenicity studies of aristolochic acids in experimental animals. We propose that spatiotemporal heterogeneity in the carcinogenicity of these phytochemicals could explain why direct evidence of aristolochic acids causing liver cancer has never been found in adult individuals. We also summarized the reported approaches to mitigate aristolochic acid-induced hepatotoxicity to better address the associated global safety issue and provide directions and recommendations for future investigation.

Gut tumors in flies alter the taste valence of an anti-tumorigenic bitter compound

The sense of taste is essential for survival, as it allows animals to distinguish between foods that are nutritious from those that are toxic. However, innate responses to different tastants can be modulated or even reversed under pathological conditions. Here, we examined whether and how the internal status of an animal impacts taste valence by using Drosophila models of hyperproliferation in the gut. In all three models where we expressed proliferation-inducing transgenes in intestinal stem cells (ISCs), hyperproliferation of ISCs caused a tumor-like phenotype in the gut. While tumor-bearing flies had no deficiency in overall food intake, strikingly, they exhibited an increased gustatory preference for aristolochic acid (ARI), which is a bitter and normally aversive plant-derived chemical. ARI had anti-tumor effects in all three of our gut hyperproliferation models. For other aversive chemicals we tested that are bitter but do not have anti-tumor effects, gut tumors did not affect avoidance behaviors. We demonstrated that bitter-sensing gustatory receptor neurons (GRNs) in tumor-bearing flies respond normally to ARI. Therefore, the internal pathology of gut hyperproliferation affects neural circuits that determine taste valence postsynaptic to GRNs rather than altering taste identity by GRNs. Overall, our data suggest that increased consumption of ARI may represent an attempt at self-medication. Finally, although ARI's potential use as a chemotherapeutic agent is limited by its known toxicity in the liver and kidney, our findings suggest that tumor-bearing flies might be a useful animal model to screen for novel anti-tumor drugs.

Detection and Removal of Aristolochic Acid in Natural Plants, Pharmaceuticals, and Environmental and Biological Samples: A Review

Aristolochic acids (AAs) are a toxic substance present in certain natural plants. Direct human exposure to these plants containing AAs leads to a severe and irreversible condition known as aristolochic acid nephropathy (AAN). Additionally, AAs accumulation in the food chain through environmental mediators can trigger Balkan endemic nephropathy (BEN), an environmental variant of AAN. This paper presents a concise overview of the oncogenic pathways associated with AAs and explores the various routes of environmental exposure to AAs. The detection and removal of AAs in natural plants, drugs, and environmental and biological samples were classified and summarized, and the advantages and disadvantages of the various methods were analyzed. It is hoped that this review can provide effective insights into the detection and removal of AAs in the future.

MiR-766-3p and miR-671-5p attenuate aristolochic acid-induced hepatotoxicity by directly targeting the key bioactivating enzyme NQO1

Aristolochic acid (AA) as an emerging contaminant in herbal medicines or crops has been well-recognized for causing nephropathy since 1990s. Over the last decade, mounting evidence has linked AA to liver injury; however, the underlying mechanism is poorly elucidated. MicroRNAs respond to environmental stress and mediate multiple biological processes, thus showing biomarker potentials prognostically or diagnostically. In the present study, we investigated the role of miRNAs in AA-induced hepatotoxicity, specifically in regulating NQO1, the key enzyme responsible for AA bioactivation. In silico analysis showed that hsa-miR-766-3p and hsa-miR-671-5p were significantly associated with AAI exposure as well as NQO1 induction. A 28-day rat experiment of 20 mg/kg AA exposure demonstrated a 3-fold increase of NQO1 and an almost 50 % decrease of the homologous miR-671 that were accompanied with liver injury, which was consistent with in silico prediction. Further mechanistic investigation using Huh7 cells with IC50 of AAI at 146.5 µM showed both hsa-miR-766-3p and hsa-miR-671-5p were able to directly bind to and down-regulate NQO1 basal expression. In addition, both miRNAs were shown to suppress AAI-induced NQO1 upregulation in Huh7 cells at a cytotoxic concentration of 70 μM, and consequently alleviate AAI-induced cellular effects, including cytotoxicity and oxidative stress. Together, these data illustrate that miR-766-3p and miR-671-5p attenuate AAI-induced hepatotoxicity, and thus have monitoring and diagnostic potentials.

Grape seed extract proanthocyanidin antagonizes aristolochic acid I-induced liver injury in rats by activating PI3K-AKT pathway

Aristolochic acid is internationally recognized as a carcinogen. It has been shown that the main toxic mechanism of aristolochic acid on the liver and kidney is the induction of ROS-induced oxidative stress damage. To investigate whether proanthocyanidins (GSPE), a natural antioxidant product from grape seed extract, could antagonize AA-I-induced liver injury. Thirty-two SD rats were selected and divided into aristolochic acid exposure group (AA-I), normal control group, GSPE group and GSPE intervention group. The protective effects of GSPE on AA-I liver injury were evaluated by examining the body weight, liver index, liver function and liver pathological sections of rats. The results of body weight, liver index, liver function and liver pathological sections of rats showed that GSPE had antagonistic effects on AA-I-induced liver injury. antioxidant enzyme activity in the GSPE intervention group was significantly higher than that in the aristolochic acid group, apoptotic cells were significantly lower than that in the aristolochic acid group, protein and mRNA expression of PI3K-AKT and BCL-2 were significantly higher than that in the aristolochic acid group, BAX, The protein and mRNA expression of BAX, CASPAES-3, CASPAES-9 were significantly lower than those of the aristolochic acid group. GSPE can antagonize aristolochic acid-induced hepatotoxicity, and its mechanism of action is to antagonize aristolochic acid I-induced liver injury by inhibiting PI3K-AKT pathway-mediated hepatocyte apoptosis.

Dissection of cellular and molecular mechanisms of aristolochic acid-induced hepatotoxicity via single-cell transcriptomics

Background

Aristolochic acids (AAs), a class of carcinogenic and mutagenic natural products from Aristolochia and Asarum plants, are well-known to be responsible for inducing nephrotoxicity and urothelial carcinoma. Recently, accumulating evidence suggests that exposure to AAs could also induce hepatotoxicity and even hepatocellular carcinoma, though the mechanisms are poorly defined.

Methods

Here, we aimed to dissect the underlying cellular and molecular mechanisms of aristolochic acid I (AAI)-induced hepatotoxicity by using advanced single-cell RNA sequencing (scRNA-seq) and proteomics techniques. We established the first single-cell atlas of mouse livers in response to AAI.

Results

In hepatocytes, our results indicated that AAI activated NF-κB and STAT3 signaling pathways, which may contribute to the inflammatory response and apoptosis. In liver sinusoidal endothelial cells (LSECs), AAI activated multiple oxidative stress and inflammatory associated signaling pathways and induced apoptosis. Importantly, AAI induced infiltration of cytotoxic T cells and activation of proinflammatory macrophage and neutrophil cells in the liver to produce inflammatory cytokines to aggravate inflammation.

Conclusions

Collectively, our study provides novel knowledge of AAs-induced molecular characteristics of hepatotoxicity at a single-cell level and suggests future treatment options for AAs associated hepatotoxicity.