Psoralidin, a major component of Psoraleae Fructus, induces inflammasome activation and idiosyncratic liver injury

Bavachinin, a main compound of Psoraleae Fructus, facilitates GSDMD-mediated pyroptosis and causes hepatotoxicity in mice

Psoraleae Fructus (PF, Psoralea corylifolia L.), a traditional medicine with a long history of application, is widely used clinically for the treatment of various diseases. However, the reports of PF-related adverse reactions, such as hepatotoxicity, phototoxic dermatitis, and allergy, are increasing year by year, with liver injury being the mostly common. Our previous studies have demonstrated that PF and its preparations can cause liver injury in lipopolysaccharide (LPS)-mediated susceptibility mouse model, but the mechanism of PF-related liver injury is unclear. In this study, we showed that PF and bavachinin, a major component of PF, can directly induce the expression of caspase-1 and interleukin-1β (IL-1β), indicating that PF and bavachinin can directly triggered the activation of inflammasome. Furthermore, pretreatment with NLR family pyrin domain-containing 3 (NLRP3), NLR family CARD domain containing 4 (NLRC4) or absent in melanoma 2 (AIM2) inflammasome inhibitors, containing MCC950, ODN TTAGGG (ODN) and carnosol, all significantly reversed bavachinin-induced inflammasome activation. Mechanistically, bavachinin dose-dependently promote Gasdermin D (GSDMD) post-shear activation and then induce mitochondrial reactive oxygen species (mtROS) production and this effect is markedly inhibited by pretreatment with N-Acetylcysteine amide (NAC). In addition, combination treatment of LPS and bavachinin significantly induced liver injury in mice, but not LPS or bavachinin alone, and transcriptome analysis further validated these results. Thus, PF and bavachinin can induce the activation of inflammasome by promoting GSDMD cleavage and cause hepatotoxicity in mice. Therefore, PF, bavachinin, and PF-related preparations should be avoided in patients with inflammasome activation-associated diseases.

Exploring the anti-inflammatory and immunomodulatory potential of licochalcone B against psoralidin-induced liver injury

ETHNOPHARMACOLOGICAL RELEVANCE

Herb-induced liver injury (HILI) represents an exacerbated inflammatory response, with Psoraleae fructus (PF) and its preparations recently associated with hepatotoxicity. Licorice, historically recognized as a detoxifying herbal remedy, is considered to possess hepatoprotective properties. Our previous research identified bavachin, bakuchiol, and psoralidin (PSO) as potential toxic constituents in PF, while licochalcone B (LCB) and echinatin were identified as bioactive components in licorice. However, evidence regarding the interactions of active compounds in herbs and their underlying mechanisms remains limited.

AIM OF THE STUDY

The objective of this study is to assess the potential mechanisms through which LCB modulates immunological and anti-inflammatory responses to treat PSO-induced liver injury by using human hepatocyte cells (L02) and LPS-primed mice.

METHODS

The ameliorative effects of LCB and echinatin on bavachin, bakuchiol, and PSO-induced liver injury were demonstrated in L02 cells. Subsequently, the efficacy of LCB on PSO-induced idiosyncratic liver injury was further validated in C57BL/6 mice under moderate inflammatory stress induced by LPS priming. The mechanisms were preliminarily explored with an integrated strategy of molecular docking, RT-PCR verification, and untargeted metabolomics.

RESULTS

The study shows that LCB significantly reduced cell injury induced by the three chemicals in PF and provided substantial protection against PSO-induced hepatic damage, as indicated by the levels of ALT, AST, and LDH. LCB normalized liver function and remarkedly alleviated hepatic lesions and inflammation caused by PSO in mice under moderate inflammatory stress. The mRNA profiles of both L02 cells and mice liver tissue revealed that LCB mitigated PSO-induced hepatotoxicity by regulating the gene expression of pro-inflammatory cytokines IL1B and TNF, as well as immunoinflammatory genes PIK3CA, AKT1, NFKB1, and NLRP3. Furthermore, untargeted metabolomics of liver tissue indicated that LCB could reverse the abnormal expression of 11 discriminatory metabolites, with the interrelationship between differential metabolites and target genes primarily clustering in glycerophospholipid metabolism, arachidonic acid metabolism, and phosphatidylinositol signaling system.

CONCLUSION

LCB demonstrated a superior anti-inflammatory and immunomodulatory effect on PSO-induced hepatotoxicity by modulating the inflammatory response and metabolic signaling system. Key interactive targets included phosphatidylcholine, phosphatidic acid, and subunit isoforms of PI3K.

The acute oral toxicity test of ethanol extract of salt-processed Psoraleae Fructus and its acute hepatotoxicity and nephrotoxicity risk assessment

ETHNOPHARMACOLOGICAL RELEVANCE

Psoraleae Fructus is a well-known Traditional Chinese Medicine which has long been used to warm and tonify the kidney and treat diseases such as osteoporosis and diarrhea. However, it may cause multiorgan injury, which limited its use.

AIM OF THE STUDY

The aim of this study was to identify the components of ethanol extract of salt-processed Psoraleae Fructus (EEPF) and systematically investigate its acute oral toxicity and the mechanism underlying its acute hepatotoxicity.

MATERIALS AND METHODS

In this study, the UHPLC-HRMS analysis was carried out for components identification. Followed by acute oral toxicity test in Kunming mice, which received oral gavage of EEPF from 3.85 to 78.00 g/kg. Body weight, organ indexes, biochemical analysis, morphology, histopathology, oxidative stress state, TUNEL, mRNA and protein expression of NLRP3/ASC/Caspase-1/GSDMD signaling pathway were evaluated to study the EEPF-induced acute hepatotoxicity and its underlying mechanisms.

RESULTS

The results showed that 107 compounds such as psoralen and isopsoralen were identified in EEPF. And the acute oral toxicity test demonstrated the LD₅₀ of EEPF was 15.95 g/kg in Kunming mice. The survival mice displayed non-significant difference in body weight compared with Control at the end of the observation period. And the organ indexes of heart, liver, spleen, lung, and kidney showed no significant difference. However, the morphological and histopathological changes of these organs in high-dose-groups mice indicated that the liver and kidney might be the main target toxic organs of EEPF, which showed hepatocyte degeneration with lipid droplets and protein cast in kidney. It could be confirmed by the significant increases of liver and kidney function parameters such as AST, ALT, LDH, BUN, and Crea. In addition, the oxidative stress markers, MDA in the liver and kidney was significantly increased while SOD, CAT, GSH-Px (only liver), and GSH were significantly decreased. Furthermore, EEPF increased the TUNEL-positive cells and the mRNA and protein expression of NLRP3, Caspase-1, ASC and GSDMD in liver with increased protein expression of IL-1β and IL-18. Notably, cell viability test showed that the specific inhibitor of Caspase-1 could reverse the Hep-G2 cell death induced by EEPF.

CONCLUSION

To summarize, this study analyzed the 107 compounds of EEPF. The acute oral toxicity test demonstrated the LD₅₀ value of EEPF was 15.95 g/kg in Kunming mice and the liver and kidney might be the main target toxic organs of EEPF. It caused liver injury through oxidative stress and pyroptotic damage via NLRP3/ASC/Caspase-1/GSDMD signaling pathway.

Cytochrome P450-mediated herb-drug interaction (HDI) of Polygonum multiflorum Thunb. based on pharmacokinetic studies and in vitro inhibition assays

BACKGROUND

Polygonum multiflorum Thunb. (PM) is well known both in China and other countries of the world for its tonic properties, however, it has lost its former glory due to liver toxicity incidents in recent years.

PURPOSE

The purpose of this study is to determine whether the occurrence of herb-drug interaction (HDI) caused by PM is associated with cytochrome P450 (CYP450) based on pharmacokinetic studies and in vitro inhibition assays. The objective was to provide a reference for the rational and safe use of drugs in clinical practice.

METHODS

In this study, raw PM (R), together with its two processed products which included PM by Chinese Pharmacopoeia (M) and PM by "nine cycles of steaming and sunning (NCSS)" ("9"), were prepared as the main research objects. A method based on fluorescence technology was used to evaluate the inhibition levels of raw and processed PMs, as well as corresponding characteristic compounds on seven recombinant human cytochrome P450s (rhCYP450s). The pharmacokinetics of sulindac (a representative of commonly used nonsteroidal anti-inflammatory drugs) and psoralen (a major compound of Psoralea in combination with PM) in rat plasma were studied when combined with raw and different processed products of PM.

RESULTS

The inhibitory level order of the three extracts on major different subtypes of CYP450 (CYP1A2, CYP2B6, CYP2C8, CYP2C19, CYP2D6, and CYP3A4) was: R > M > "9". However, the inhibition level of R and "9" is higher than that of M on CYP2C9. Further studies showed that trans-THSG and emodin could selectively inhibit CYP3A4 and CYP1A2, respectively. Epicatechin gallate mainly inhibited CYP3A4 and CYP1A2, followed by CYP2C8 and CYP2C9. Genistein mainly inhibited CYP3A4, followed by CYP2C9 and CYP2C8. CYP3A4 and CYP2C9 were also inhibited by daidzein. The inhibitory effects of all the PM extracts were associated with their characteristic compounds. The results of HDI showed that R increased sulindac exposure to rat blood, and R and M increased psoralen exposure to rat blood, which were consistent with corresponding metabolic enzymes. Overall, the in vitro and in vivo results indicated that PM, especially R, would be at high risk to cause toxicity and drug interactions via CYP450 inhibition.

CONCLUSION

This study not only elucidates the scientific connotation of "efficiency enhancement and toxicity reduction" of PM by NCSS from the perspective of metabolic inhibition but also contributes to HDI prediction and appropriate clinical medication of PM.

The mechanism of NLRP3 inflammasome activation and its pharmacological inhibitors

NLRP3 (NOD-, LRR-, and pyrin domain-containing protein 3) is a cytosolic pattern recognition receptor (PRR) that recognizes multiple pathogen-associated molecular patterns (PAMPs) and damage-associated molecular patterns (DAMPs). Once activated, NLRP3 initiates the inflammasome assembly together with the adaptor ASC and the effector caspase-1, leading to caspase-1 activation and subsequent cleavage of IL-1β and IL-18. Aberrant NLRP3 inflammasome activation is linked with the pathogenesis of multiple inflammatory diseases, such as cryopyrin-associated periodic syndromes, type 2 diabetes, non-alcoholic steatohepatitis, gout, and neurodegenerative diseases. Thus, NLRP3 is an important therapeutic target, and researchers are putting a lot of effort into developing its inhibitors. The review summarizes the latest advances in the mechanism of NLRP3 inflammasome activation and its pharmacological inhibitors.

The progression of chronicity and autoimmune hepatitis in recurrent drug-induced liver injury

BACKGROUND AND AIMS

Recurrent drug-induced liver injury (DILI) is not well documented. We retrospectively analysed the characteristics of patients who had a history of two separate DILI episodes due to different drugs.

METHODS

We collected data from 57 patients with recurrent DILI from 9582 confirmed DILI cases. Demographic, laboratory, and clinical data from both episodes were collected and analysed to determine the relationship between recurrent DILI, chronic DILI, and autoimmune hepatitis (AIH).

RESULTS

The incidence rate of recurrent DILI in our cohort was 0.59%. Most of the 57 patients with recurrent DILI were female (73.68%). The latency period of the initial episode was 30 days, whereas that of the second episode was 13 days (P = 0.003). The pattern of liver injury was not significantly different between episodes (P = 0.52). Laboratory indicators, such as alanine aminotransferase, aspartate transaminase, alkaline phosphatase, and total bilirubin, were significantly lower in the second episode than in the initial episode (P < 0.05). The incidence of chronic DILI was 43.86% during the initial episode and increased to 63.16% during the second episode. After the initial episode, 15 patients developed AIH during the second episode.

CONCLUSIONS

The latency period of recurrent DILI was gradually shortened. The clinical indices of liver injury tended to be less elevated during the second episode. Female post-menopausal patients with abnormal serum immunoglobulin G levels may be predisposed to AIH. The second DILI episode was more likely to have features of AIH.

Inflammasomes and Pyroptosis of Liver Cells in Liver Fibrosis

Inflammasomes are multiprotein complexes that can sense danger signals and activate caspase-1 to mediate pro-inflammatory cytokines release and pyroptotic cell death. There are two main canonical and non-canonical signaling pathways that trigger inflammasome activation. Inflammasomes are expressed and assembled in parenchymal and nonparenchymal cells in response to liver injury in the liver. Additionally, the hepatocytes, biliary epithelial cells (cholangiocytes), hepatic stellate cells (HSCs), hepatic macrophages, and liver sinusoidal endothelial cells (LSECs) contribute to liver fibrosis via different mechanisms. However, the underlying mechanism of the inflammasome and pyroptosis in these liver cells in liver fibrosis remains elusive. This review summarizes the activation and function of inflammasome complexes and then discusses the association between inflammasomes, pyroptosis, and liver fibrosis. Unlike other similar reviewers, we will focus on the effect of inflammasome activation and pyroptosis in the various liver cells during the development of liver fibrosis. We will also highlight the latest progress of pharmacological intervention in inflammasome-mediated liver fibrosis.

A new strategy for the rapid identification and validation of direct toxicity targets of psoralen-induced hepatotoxicity

The interaction between small-molecule compounds of traditional Chinese medicine and their direct targets is the molecular initiation event, which is the key factor for toxicity efficacy. Psoralen, an active component of Fructus Psoraleae, is toxic to the liver and has various pharmacological properties. Although the mechanism of psoralen-induced hepatotoxicity has been studied, the direct target of psoralen remains unclear. Thus, the aim of this study was to discover direct targets of psoralen. To this end, we initially used proteomics based on drug affinity responsive target stability (DARTS) technology to identify the direct targets of psoralen. Next, we used surface plasmon resonance (SPR) analysis and verified the affinity effect of the 'component-target protein'. This method combines molecular docking technology to explore binding sites between small molecules and proteins. SPR and molecular docking confirmed that psoralen and tyrosine-protein kinase ABL1 could be stably combined. Based on the above experimental results, ABL1 is a potential direct target of psoralen-induced hepatotoxicity. Finally, the targets Nrf2 and mTOR, which are closely related to the hepatotoxicity caused by psoralen, were predicted by integrating proteomics and network pharmacology. The direct target ABL1 is located upstream of Nrf2 and mTOR, Nrf2 can influence the expression of mTOR by affecting the level of reactive oxygen species. Immunofluorescence experiments and western blot results showed that psoralen could affect ROS levels and downstream Nrf2 and mTOR protein changes, whereas the ABL1 inhibitor imatinib and ABL1 agonist DPH could enhance or inhibit this effect. In summary, we speculated that when psoralen causes hepatotoxicity, it acts on the direct target ABL1, resulting in a decrease in Nrf2 expression, an increase in ROS levels and a reduction in mTOR expression, which may cause cell death. We developed a new strategy for predicting and validating the direct targets of psoralen. This strategy identified the toxic target, ABL1, and the potential toxic mechanism of psoralen.

NLRP3 Inflammasome: A Promising Therapeutic Target for Drug-Induced Toxicity

Drug-induced toxicity, which impairs human organ function, is a serious problem during drug development that hinders the clinical use of many marketed drugs, and the underlying mechanisms are complicated. As a sensor of infections and external stimuli, nucleotide-binding oligomerization domain (NOD)-like receptor family pyrin domain containing 3 (NLRP3) inflammasome plays a key role in the pathological process of various diseases. In this review, we specifically focused on the role of NLRP3 inflammasome in drug-induced diverse organ toxicities, especially the hepatotoxicity, nephrotoxicity, and cardiotoxicity. NLRP3 inflammasome is involved in the initiation and deterioration of drug-induced toxicity through multiple signaling pathways. Therapeutic strategies via inhibiting NLRP3 inflammasome for drug-induced toxicity have made significant progress, especially in the protective effects of the phytochemicals. Growing evidence collected in this review indicates that NLRP3 is a promising therapeutic target for drug-induced toxicity.