Alterations of Cytochrome P450-Mediated Drug Metabolism during Liver Repair and Regeneration after Acetaminophen-Induced Liver Injury in Mice

Paeonia lactiflora Pall. ameliorates acetaminophen-induced oxidative stress and apoptosis via inhibiting the PKC-ERK pathway

ETHNOPHARMACOLOGICAL RELEVANCE

Paeonia lactiflora Pall. (PLP), a traditional Chinese medicine, is recognized for its antioxidative and anti-apoptotic properties. Despite its potential medicinal value, the mechanisms underlying its efficacy have been less explored, particularly in alleviating acute liver injury (ALI) caused by excessive intake of acetaminophen (APAP).

AIM OF THE STUDY

This study aims to elucidate the role and mechanisms of PLP in mitigating oxidative stress and apoptosis induced by APAP.

MATERIALS AND METHODS

C57BL/6 male mice were pre-treated with PLP for seven consecutive days, followed by the induction of ALI using APAP. Liver pathology was assessed using HE staining. Serum indicators, immunofluorescence (IF), immunohistochemical (IHC), and transmission electron microscopy were employed to evaluate levels of oxidative stress, ferroptosis and apoptosis. Differential expression proteins (DEPs) in the APAP-treated and PLP pre-treated groups were analyzed using quantitative proteomics. Subsequently, the potential mechanisms of PLP pre-treatment in treating ALI were validated using western blotting, molecular docking, molecular dynamics simulations, and surface plasmon resonance (SPR) analysis.

RESULTS

The UHPLC assay confirmed the presence of three compounds, i.e., albiflorin, paeoniflorin, and oxypaeoniflorin. Pre-treatment with PLP was observed to ameliorate liver tissue pathological damage through HE staining. Further confirmation of efficacy of PLP in alleviating APAP-induced liver injury and oxidative stress was established through liver function serum biochemical indicators, IF of reactive oxygen species (ROS) and IHC of glutathione peroxidase 4 (GPX4) detection. However, PLP did not demonstrate a significant effect in alleviating APAP-induced ferroptosis. Additionally, transmission electron microscopy and TUNEL staining indicated that PLP can mitigate hepatocyte apoptosis. PKC-ERK pathway was identified by proteomics, and subsequent molecular docking, molecular dynamics simulations, and SPR verified binding of the major components of PLP to ERK protein. Western blotting demonstrated that PLP suppressed protein kinase C (PKC) phosphorylation, blocking extracellular signal-regulated kinase (ERK) phosphorylation and inhibiting oxidative stress and cell apoptosis.

CONCLUSION

This study demonstrates that PLP possesses hepatoprotective abilities against APAP-induced ALI, primarily by inhibiting the PKC-ERK cascade to suppress oxidative stress and cell apoptosis.

Transcriptomic signature, bioactivity and safety of a non-hepatotoxic analgesic generating AM404 in the midbrain PAG region

Safe and effective pain management is a critical healthcare and societal need. The potential for acute liver injury from paracetamol (ApAP) overdose; nephrotoxicity and gastrointestinal damage from chronic non-steroidal anti-inflammatory drug (NSAID) use; and opioids' addiction are unresolved challenges. We developed SRP-001, a non-opioid and non-hepatotoxic small molecule that, unlike ApAP, does not produce the hepatotoxic metabolite N-acetyl-p-benzoquinone-imine (NAPQI) and preserves hepatic tight junction integrity at high doses. CD-1 mice exposed to SRP-001 showed no mortality, unlike a 70% mortality observed with increasing equimolar doses of ApAP within 72 h. SRP-001 and ApAP have comparable antinociceptive effects, including the complete Freund's adjuvant-induced inflammatory von Frey model. Both induce analgesia via N-arachidonoylphenolamine (AM404) formation in the midbrain periaqueductal grey (PAG) nociception region, with SRP-001 generating higher amounts of AM404 than ApAP. Single-cell transcriptomics of PAG uncovered that SRP-001 and ApAP also share modulation of pain-related gene expression and cell signaling pathways/networks, including endocannabinoid signaling, genes pertaining to mechanical nociception, and fatty acid amide hydrolase (FAAH). Both regulate the expression of key genes encoding FAAH, 2-arachidonoylglycerol (2-AG), cannabinoid receptor 1 (CNR1), CNR2, transient receptor potential vanilloid type 4 (TRPV4), and voltage-gated Ca2+ channel. Phase 1 trial (NCT05484414) (02/08/2022) demonstrates SRP-001's safety, tolerability, and favorable pharmacokinetics, including a half-life from 4.9 to 9.8 h. Given its non-hepatotoxicity and clinically validated analgesic mechanisms, SRP-001 offers a promising alternative to ApAP, NSAIDs, and opioids for safer pain treatment.

INTEDE 2.0: the metabolic roadmap of drugs

The metabolic roadmap of drugs (MRD) is a comprehensive atlas for understanding the stepwise and sequential metabolism of certain drug in living organisms. It plays a vital role in lead optimization, personalized medication, and ADMET research. The MRD consists of three main components: (i) the sequential catalyses of drug and its metabolites by different drug-metabolizing enzymes (DMEs), (ii) a comprehensive collection of metabolic reactions along the entire MRD and (iii) a systematic description on efficacy & toxicity for all metabolites of a studied drug. However, there is no database available for describing the comprehensive metabolic roadmaps of drugs. Therefore, in this study, a major update of INTEDE was conducted, which provided the stepwise & sequential metabolic roadmaps for a total of 4701 drugs, and a total of 22 165 metabolic reactions containing 1088 DMEs and 18 882 drug metabolites. Additionally, the INTEDE 2.0 labeled the pharmacological properties (pharmacological activity or toxicity) of metabolites and provided their structural information. Furthermore, 3717 drug metabolism relationships were supplemented (from 7338 to 11 055). All in all, INTEDE 2.0 is highly expected to attract broad interests from related research community and serve as an essential supplement to existing pharmaceutical/biological/chemical databases. INTEDE 2.0 can now be accessible freely without any login requirement at: http://idrblab.org/intede/.

Natural Products for Acetaminophen-Induced Acute Liver Injury: A Review

The liver plays a vital role in metabolism, synthesis, and detoxification, but it is susceptible to damage from various factors such as viral infections, drug reactions, excessive alcohol consumption, and autoimmune diseases. This susceptibility is particularly problematic for patients requiring medication, as drug-induced liver injury often leads to underestimation, misdiagnosis, and difficulties in treatment. Acetaminophen (APAP) is a widely used and safe drug in therapeutic doses but can cause liver toxicity when taken in excessive amounts. This study aimed to investigate the hepatotoxicity of APAP and explore potential treatment strategies using a mouse model of APAP-induced liver injury. The study involved the evaluation of various natural products for their therapeutic potential. The findings revealed that natural products demonstrated promising hepatoprotective effects, potentially alleviating liver damage and improving liver function through various mechanisms such as oxidative stress and inflammation, which cause changes in signaling pathways. These results underscore the importance of exploring novel treatment options for drug-induced liver injury, suggesting that further research in this area could lead to the development of effective preventive and therapeutic interventions, ultimately benefiting patients with liver injury caused by medicine.

Epigenetic Mechanisms Contribute to Intraindividual Variations of Drug Metabolism Mediated by Cytochrome P450 Enzymes

Significant interindividual and intraindividual variations on cytochrome P450 (CYP)-mediated drug metabolism exist in the general population globally. Genetic polymorphisms are one of the major contribution factors for interindividual variations, but epigenetic mechanisms mainly contribute to intraindividual variations, including DNA methylation, histone modifications, microRNAs, and long non-coding RNAs. The current review provides analysis of advanced knowledge in the last decade on contributions of epigenetic mechanisms to intraindividual variations on CYP-mediated drug metabolism in several situations, including (1) ontogeny, the developmental changes of CYP expression in individuals from neonates to adults; (2) increased activities of CYP enzymes induced by drug treatment; (3) increased activities of CYP enzymes in adult ages induced by drug treatment at neonate ages; and (4) decreased activities of CYP enzymes in individuals with drug-induced liver injury (DILI). Furthermore, current challenges, knowledge gaps, and future perspective of the epigenetic mechanisms in development of CYP pharmacoepigenetics are discussed. In conclusion, epigenetic mechanisms have been proven to contribute to intraindividual variations of drug metabolism mediated by CYP enzymes in age development, drug induction, and DILI conditions. The knowledge has helped understanding how intraindividual variation are generated. Future studies are needed to develop CYP-based pharmacoepigenetics to guide clinical applications for precision medicine with improved therapeutic efficacy and reduced risk of adverse drug reactions and toxicity. SIGNIFICANCE STATEMENT: Understanding epigenetic mechanisms in contribution to intraindividual variations of CYP-mediated drug metabolism may help to develop CYP-based pharmacoepigenetics for precision medicine to improve therapeutic efficacy and reduce adverse drug reactions and toxicity for drugs metabolized by CYP enzymes.

Metabolic competency of larval zebrafish in drug-induced liver injury: a case study of acetaminophen poisoning

Larval zebrafish is emerging as a new model organism for studying drug-induced liver injury (DILI) with superiorities in visual assessment, genetic engineering as well as high throughput. Metabolic bioactivation to form reactive intermediates is a common event that triggers DILI. This study first addressed the correlation between acetaminophen metabolism and hepatotoxicity in zebrafish larvae (3 days post-fertilization) and demonstrated the occurrence of cytochrome P450 enzymes-mediated APAP bioactivation at early developmental stage through characterizing the dose-effect (0-1.6 mg/mL) and the time-course (0-72 h) of liver injury and metabolism in the AB strain and LiPan transgenic line Tg(lfabp10a: DsRed; elaA: egfp) expressing liver-specific fluorescent protein. APAP caused multi-organ developmental retardation and elicited dose- and time-dependent hepatotoxicity. Liver imaging revealed significant changes earlier than histological and biochemical measurements. APAP bioactivation in larval zebrafish was first confirmed by the detection of the glutathione conjugate of the reactive intermediate NAPQI (NAPQI-GSH) and subsequent mercapturate derivatives NAPQI-cysteine and NAPQI-N-acetylcysteine after even short (0.5-hour post exposure) or low (0.2 mg/mL) APAP exposure. APAP overdose impaired metabolic function, in particular sulfation, while facilitated GSH depletion and APAP sulfate excretion. Meanwhile, APAP displayed triphasic accumulation in the larvae, agreeing with fluctuating metabolic capabilities with sulfation dominating the early larval developmental stage. Most importantly, the dose-response effects and time-course of APAP accumulation and metabolism agree well with those of the liver injury development. Overall, larval zebrafish has developed mammalian-like metabolic function, enabling it an ideal model organism for high throughput screening hepatotoxicity and mechanistic study of bioactivation-based DILI.

Tanshinone IIA prevents acetaminophen-induced nephrotoxicity through the activation of the Nrf2-Mrp2/4 pathway in mice

It's known that APAP overdose often leads to hepatotoxicity and nephrotoxicity. In the present study, we investigated the preventative effect of Tan IIA on APAP-induced nephrotoxicity. Mice were orally administrated with Tan IIA (10 or 30 mg/kg/day) for 1 week and subsequently gavaged with 200 mg/kg of APAP. Tan IIA reduced APAP-induced nephrotoxicity as evidenced by histopathological evaluation and serum creatinine levels. Tan IIA pretreatment promoted the efflux of the toxic intermediate metabolite N-acetyl-p-benzoquinone imine (NAPQI), thus reduced its injury to mouse kidney. After Tan IIA pretreatment, a remarkable increase in mRNA and protein expression of Nrf2 and its target genes Mrp2 and Mrp4 was observed in Nrf2^+/+ mice kidneys, however, no obvious change of Mrp2 and Mrp4 mRNA and protein expression was detected in Nrf2^-/- mice kidneys. HK-2 cells were used for exploring the roles of Tan IIA in the Nrf2-MRPs pathway in vitro. Consistently, Tan IIA up-regulated the Nrf2-MRPs pathway and promoted the nuclear Nrf2 accumulation in HK-2 cells. Collectively, our findings suggested that Tan IIA facilitated the clearance of toxic intermediate metabolite NAPQI from the kidney through upregulation of the Nrf2-MRP2/4 pathway, thereby, performing preventive effects against APAP-induced nephrotoxicity.

Physiologically-Based Pharmacokinetic Modeling Approaches for Patients with SARS-CoV-2 Infection: A Case Study with Imatinib

Severe acute respiratory syndrome coronavirus 2 (SARS‐CoV‐2) infection, which causes coronavirus disease 2019 (COVID‐19), manifests as mild respiratory symptoms to severe respiratory failure and is associated with inflammation and other physiological changes. Of note, substantial increases in plasma concentrations of α₁‐acid‐glycoprotein and interleukin‐6 have been observed among patients admitted to the hospital with advanced SARS‐CoV‐2 infection. A physiologically based pharmacokinetic (PBPK) approach is a useful tool to evaluate and predict disease‐related changes on drug pharmacokinetics. A PBPK model of imatinib has previously been developed and verified in healthy people and patients with cancer. In this study, the PBPK model of imatinib was successfully extrapolated to patients with SARS‐CoV‐2 infection by accounting for disease‐related changes in plasma α₁‐acid‐glycoprotein concentrations and the potential drug interaction between imatinib and dexamethasone. The model demonstrated a good predictive performance in describing total and unbound imatinib concentrations in patients with SARS‐CoV‐2 infection. PBPK simulations highlight that an equivalent dose of imatinib may lead to substantially higher total drug concentrations in patients with SARS‐CoV‐2 infection compared to that in patients with cancer, while the unbound concentrations remain comparable between the 2 patient populations. This supports the notion that unbound trough concentration is a better exposure metric for dose adjustment of imatinib in patients with SARS‐CoV‐2 infection, compared to the corresponding total drug concentration. Potential strategies for refinement and generalization of the PBPK modeling approach in the patient population with SARS‐CoV‐2 are also provided in this article, which could be used to guide study design and inform dose adjustment in the future.

Long Noncoding RNAs Hepatocyte Nuclear Factor 4A Antisense RNA 1 and Hepatocyte Nuclear Factor 1A Antisense RNA 1 are Involved in Ritonavir-induced Cytotoxicity in Hepatoma Cells

Ritonavir (RTV), a pharmacoenhancer used in anti-HIV regimens, can induce liver damage. RTV is primarily metabolized by cytochrome P450 3A4 (CYP3A4) in the liver. HNF4A antisense RNA 1 (HNF4A-AS1) and HNF1A antisense RNA 1 (HNF1A-AS1) are long noncoding RNAs (lncRNAs) that regulate the expression of pregnane X receptor (PXR) and CYP3A4. This study investigated the role and underlying mechanisms of HNF4A-AS1 and HNF1A-AS1 in RTV-induced hepatotoxicity. HNF4A-AS1 and HNF1A-AS1 were knocked down by small hairpin RNAs in Huh7 and HepG2 cells. Lactate dehydrogenase and reactive oxygen species assays were performed to assess RTV-induced hepatotoxicity. Chromatin immunoprecipitation qPCR was used to detect PXR enrichment and histone modifications in the CYP3A4 promoter. HNF4A-AS1 knockdown increased PXR and CYP3A4 expression and exacerbated RTV-induced cytotoxicity, whereas HNF1A-AS1 knockdown generated the opposite phenotype. Mechanistically, enrichment of PXR and trimethylation of histone 3 lysine 4 (H3K4me3) in the CYP3A4 promoter was increased, and trimethylation of histone 3 lysine 27 (H3K27me3) was decreased after HNF4A-AS1 knockdown. However, PXR and H3K4me3 enrichment decreased after HNF1A-AS1 knockdown. Alterations in RTV-induced hepatotoxicity caused by decreasing HNF4A-AS1 or HNF1A-AS1 were reversed by knockdown or overexpression of PXR. Increased susceptibility to RTV-induced liver injury caused by the PXR activator rifampicin was attenuated by HNF4A-AS1 overexpression or HNF1A-AS1 knockdown. Taken together, these results revealed that HNF4A-AS1 and HNF1A-AS1 modulated RTV-induced hepatotoxicity by regulating CYP3A4 expression, primarily by affecting the binding of PXR and histone modification status in the CYP3A4 promoter. Significance Statement HNF4A-AS1 and HNF1A-AS1, transcribed separately from neighboring antisense genes of the human transcription factor genes HNF4A and HNF1A, were identified as lncRNAs that can affect RTV-induced hepatotoxicity and susceptibility to RTV-induced hepatotoxicity caused by rifampicin exposure, mainly by affecting the expression of CY3A4 via alterations in PXR enrichment and histone modification status in the CYP3A4 promoter. This discovery provides directions for further research on the mechanisms of RTV-induced liver injury.