An integrated strategy combining network toxicology and feature-based molecular networking for exploring hepatotoxic constituents and mechanism of Epimedii Folium-induced hepatotoxicity in vitro

Integrated bioinformatics and multi-omics to investigate the mechanism of Rhododendron molle Flos-induced hepatotoxicity

ETHNOPHARMACOLOGICAL RELEVANCE

Drug-induced liver injury (DILI) is an important and common adverse drug event. Rhododendron molle Flos (RMF), as one of toxic Traditional Chinese medicines (TCMs), holds a prominent position in clinical practice for treating rheumatoid arthritis. However, the toxicity of RMF limits its safe. Most of the concerns are about its rapid neurotoxicity and cardiotoxicity, with less attention paid to its hepatotoxicity, and the mechanism of which is still unclear.

AIM OF THE STUDY

To reveal the mechanism of RMF-induced hepatotoxicity by bioinformatics and multi-omics.

MATERIALS AND METHODS

Rats were intragastric administered RMF at doses of 0.8 g/kg, 0.4 g/kg, and 0.2 g/kg once daily for 2 weeks. Initially, hepatotoxicity was then evaluated using liver function enzymes, antioxidant enzymes, and histopathology. Subsequently, network toxicology, transcriptomics, and metabolomics were used to identify the genes and metabolites. In addition, molecular docking and Western blot were employed to verify toxic components and key targets.

RESULTS

RMF caused abnormal levels of ALT, γ-GT, TBIL, and TBA in the serum of rats, as well as abnormal levels of MDA, GSH-Px, and SOD in the liver, leading to inflammatory infiltration of liver cells, with a dose-dependent manner. RMF disordered the steroid hormone biosynthesis, pyruvate metabolism, fatty acid biosynthesis, and arachidonic acid metabolism. Six key targets were identified- UGT1A6, CYP2E1, ACOT1, ACSL5, CTH, and PKLR, along with their corresponding metabolites, namely 17β-estradiol, estriol, arachidonic acid, octadecanoic acid, and pyruvic acid. The hepatotoxicity could be attributed to five diterpenoid components, including grayanotoxin-III, rhodojaponin (RJ)-I, RJ-II, RJ-III, and RJ-V.

CONCLUSIONS

This study comprehensively identified the toxic components, upstream targets, and downstream metabolites of RMF-induced liver toxicity, providing a basis for evaluating and monitoring liver function in patients during clinical application.

Integration of network toxicology and transcriptomics reveals the novel neurotoxic mechanisms of 2, 2', 4, 4'-tetrabromodiphenyl ether

The brominated flame retardant 2, 2', 4, 4'-tetrabromodiphenyl ether (PBDE-47) is known as a developmental neurotoxicant, yet the underlying mechanisms remain unclear. This study aims to explore its neurotoxic mechanisms by integrating network toxicology with transcriptomics based on human neural precursor cells (hNPCs) and neuron-like PC12 cells. Network toxicology revealed that PBDE-47 crosses the blood-brain barrier more effectively than heavier PBDE congeners, and is associated with disruptions in 159 biological pathways, including cytosolic DNA-sensing pathway, ferroptosis, cellular senescence, and chemokine signaling pathway. Additionally, transcriptomic analyses of hNPCs and PC12 cells exposed to PBDE-47 uncovered substantial gene expression changes, with 855 and 702 genes up- and down-regulated in hNPCs, and 2844 and 2711 genes in PC12 cells, respectively. These differentially expressed genes were primarily implicated in crucial processes like neuroactive ligand-receptor interaction, nucleocytoplasmic transport, ferroptosis, p53 signaling, and cell cycle regulation. Integration of the results identified novel mechanisms of PBDE-47 neurotoxicity, such as neuroinflammation and cellular senescence, alongside established mechanisms like ferroptosis, apoptosis and cell cycle arrest. Overall, these findings provide critical insights into the mechanisms of PBDE-47 neurotoxicity, highlighting the integration of network toxicology and transcriptomics as a novel study approach to explore the modes of action of toxicants.

Efficient analysis of adverse drug events and toxicological mechanisms of newly marketed drugs by integrating pharmacovigilance and network toxicology: selumetinib as an example

Objective

To integrate pharmacovigilance and network toxicology methods to explore the potential adverse drug events (ADEs) and toxic mechanisms of selumetinib, and to provide a reference for quickly understanding the safety and toxicological mechanisms of newly marketed drugs.

Methods

Taking selumetinib as an example, this study integrated pharmacovigilance methods based on real-world data and network toxicology methods to analyze its ADE and its potential toxicological mechanism. First, the ADE reports of selumetinib were extracted from the US Food and Drug Administration (FDA) adverse event reporting system (FAERS), and the ADE signals were detected by reporting odds ratio (ROR) and UK medicines and healthcare products regulatory agency (MHRA) methods. The ADE signals were classified and described according to the preferred terms (PTs) and system organ class (SOC) derived from the Medical Dictionary for Regulatory Activities (MedDRA). The network toxicology method was used to analyze the toxicological mechanism of the interested SOCs. The specific steps included predicting the potential targets of selumetinib using TOXRIC, STITCH, ChEMBL, CTD, SwissTargetPreditcion, and Super-PRED databases, collecting the targets of SOC using GeneCards database, conducting protein-protein interaction (PPI) analysis through STRING database, conducting gene ontology (GO) and Kyoto encyclopedia of genes and genomes (KEGG) analysis through DAVID database, and testing the molecular affinity using AutoDock software.

Results

A total of 1388 ADE reports related to selumetinib were extracted, and 53 positive signals were detected by ROR and MHRA methods, of which 20 signals were not mentioned in the package insert, including ingrowing nail, hyperphosphatemia, cardiac valve disease, hematuria, neutropenia, etc. Analysis of the toxicological mechanism of six SOCs involved in positive ADE signals revealed that the key targets included EGFR, STAT3, AKT1, IL6, BCL2, etc., and the key pathways included PI3K/Akt pathway, apoptosis, ErbB signaling pathway, and EGFR tyrosine kinase inhibitor resistance, etc. Molecular docking assays showed spontaneous binding of selumetinib to key targets in these pathways.

Conclusion

The pharmacovigilance analysis identified some new potential ADEs of selumetinib, and the network toxicology analysis showed that the toxic effects of selumetinib may be related to PI3K/Akt pathway, apoptosis, ErbB signaling pathway, EGFR tyrosine kinase inhibitor resistance and other pathways.

Preface to the special issue of Food and Chemical Toxicology on "New approach methodologies and machine learning in food safety and chemical risk assessment: Development of reproducible, open-source, and user-friendly tools for exposure, toxicokinetic, and toxicity assessments in the 21st century"

This Special Issue contains articles on applications of various new approach methodologies (NAMs) in the field of toxicology and risk assessment. These NAMs include in vitro high-throughput screening, quantitative structure-activity relationship (QSAR) modeling, physiologically based pharmacokinetic (PBPK) modeling, network toxicology analysis, molecular docking simulation, omics, machine learning, deep learning, and "template-and-anchor" multiscale computational modeling. These in vitro and in silico approaches complement each other and can be integrated together to support different applications of toxicology, including food safety assessment, dietary exposure assessment, chemical toxicity potency screening and ranking, chemical toxicity prediction, chemical toxicokinetic simulation, and to investigate the potential mechanisms of toxicities, as introduced further in selected articles in this Special Issue.

Aqueous extract of Epimedium sagittatum (Sieb. et Zucc.) Maxim. induces liver injury in mice via pyroptosis

ETHNOPHARMACOLOGICAL RELEVANCE

Epimedium sagittatum (Sieb. et Zucc.) Maxim. has been used traditionally in Asia. It can dispel wind and cold, tonify the kidney, and strengthen bones and tendons. However, adverse effects of E. sagittatum have been reported, and the underlying mechanisms remain unclear.

AIM OF THE STUDY

This study aimed to investigate liver injury caused by an aqueous extract of E. sagittatum in Institute of Cancer Research (ICR) mice and explore its potential mechanisms.

MATERIALS AND METHODS

Dried E. sagittatum leaves were decocted in water to prepare aqueous extracts for ultra-high performance liquid chromatography analysis. Mice were administered an aqueous extract of E. sagittatum equivalent to either 3 g raw E. sagittatum/kg or 10 g raw E. sagittatum/kg once daily via intragastric injection for three months. The liver weights and levels of the serum biochemical parameters including alanine transaminase (ALT), aspartate aminotransferase (AST), lactate dehydrogenase (LDH), total bilirubin (TBIL), and alkaline phosphatase were measured. Hematoxylin-eosin staining was performed for histopathology. Apoptosis was detected using the TUNEL apoptosis assay kit. IL-1β was detected using ELISA kits. Proteomics was used to identify the differentially expressed proteins. Western blot analysis was performed to determine the levels of proteins significantly affected by the aqueous extract of E. sagittatum.

RESULTS

E. sagittatum treatment increased the liver weights and liver coefficients, and ALT and AST levels significantly increased (p < 0.05). A high dose of E. sagittatum significantly increased LDH and TBIL levels (p < 0.05). Ruptured cell membranes and multiple sites of inflammatory cell infiltration were also observed. No evidence of apoptosis was observed. IL-1β levels were significantly increased (p < 0.05). The expressions of PIK3R1, p-MAP2K4, p-Jun N-terminal kinase (JNK)/JNK, p-c-Jun, VDAC2, Bax, and CYC were upregulated, whereas that of Bcl-2 was inhibited by E. sagittatum. The expression of cleaved caspase-1 was significantly increased; however, its effects on GSDMD and GSDMD-N were significantly decreased. The expression levels of cleaved caspase-3 and its effector proteins GSDME and GSDME-N significantly increased.

CONCLUSIONS

Our results suggest that the aqueous extract of E. sagittatum induces liver injury in ICR mice after three months of intragastric injection via inflammatory pyroptosis.

Natural Product Baohuoside I Impairs the Stability and Membrane Location of MRP2 Reciprocally Regulated by SUMOylation and Ubiquitination in Hepatocytes

Epimedii Folium (EF) is a botanical dietary supplement to benefit immunity. Baohuoside I (BI), a prenylated flavonoid derived from EF, has exhibited the cholestatic risk before. Here, the mechanism of BI on the stability and membrane localization of liver MRP2, a bile acid exporter in the canalicular membrane of hepatocytes, was investigated. The fluorescent substrate of MRP2, CMFDA was accumulated in sandwich-cultured primary mouse hepatocytes (SCH) under BI stimulation, followed by reduced membrane MRP2 expression. BI triggered MRP2 endocytosis associated with oxidative stress via inhibition of the NRF2 signaling pathway. Meanwhile, BI promoted the degradation of MRP2 by reducing its SUMOylation and enhancing its ubiquitination level. Co-IP and fluorescence colocalization experiments all proved that MRP2 was a substrate protein for SUMOylation for SUMO proteins. CHX assays showed that SUMO1 prolonged the half-life of MRP2 and further increased its membrane expression, which could be reversed by UBC9 knockdown. Correspondingly, MRP2 accumulated in the cytoplasm by GP78 knockdown or under MG132 treatment. Additionally, the SUMOylation sites of MRP2 were predicted by the algorithm, and a conversion of lysines to arginines at positions 940 and 953 of human MRP2 caused its decreased stability and membrane location. K940 was further identified as the essential ubiquitination site for MRP2 by an in vitro ubiquitination assay. Moreover, the decreased ubiquitination of MRP2 enhanced the SUMOylation MRP2 and vice versa, and the crosstalk of these two modifiers could be disrupted by BI. Collectively, our findings indicated the process of MRP2 turnover from the membrane to cytoplasm at the post-translational level and further elucidated the novel toxicological mechanism of BI.

Arecoline-Induced Hepatotoxicity in Rats: Screening of Abnormal Metabolic Markers and Potential Mechanisms

Arecoline is a pyridine alkaloid derived from areca nut in the Arecaceae family. It has extensive medicinal activity, such as analgesic, anti-inflammatory, and anti-allergic. However, the toxicity of Arecoline limits its application. Most current studies on its toxicity mainly focus on immunotoxicity, carcinogenesis, and cancer promotion. However, there are few systematic studies on its hepatotoxicity and mechanisms. Therefore, this research explored the mechanism of hepatotoxicity induced by Arecoline in rats and analyzed endogenous metabolite changes in rat plasma by combining network toxicology with metabolomics. The differential metabolites after Arecoline exposure, such as D-Lysine, N4-Acetylaminobutanal, and L-Arginine, were obtained by metabolomics study, and these differential metabolites were involved in the regulation of lipid metabolism, amino acid metabolism, and vitamin metabolism. Based on the strategy of network toxicology, Arecoline can affect the HIF-1 signaling pathway, MAPK signaling pathway, PI3K-Akt signaling pathway, and other concerning pathways by regulating critical targets, such as ALB, CASP3, EGFR, and MMP9. Integration of metabolomics and network toxicology results were further analyzed, and it was concluded that Arecoline may induce hepatotoxicity by mediating oxidative stress, inflammatory response, energy and lipid metabolism, and cell apoptosis.