Licochalcone B specifically inhibits the NLRP3 inflammasome by disrupting NEK7-NLRP3 interaction.

The activation of the nucleotide oligomerization domain (NOD)-like receptor (NLR) family, pyrin domain-containing protein 3 (NLRP3) inflammasome is related to the pathogenesis of a wide range of inflammatory diseases, but drugs targeting the NLRP3 inflammasome are still scarce. In the present study, we demonstrated that Licochalcone B (LicoB), a main component of the traditional medicinal herb licorice, is a specific inhibitor of the NLRP3 inflammasome. LicoB inhibits the activation of the NLRP3 inflammasome in macrophages but has no effect on the activation of AIM2 or NLRC4 inflammasome. Mechanistically, LicoB directly binds to NEK7 and inhibits the interaction between NLRP3 and NEK7, thus suppressing NLRP3 inflammasome activation. Furthermore, LicoB exhibits protective effects in mouse models of NLRP3 inflammasome-mediated diseases, including lipopolysaccharide (LPS)-induced septic shock, MSU-induced peritonitis and non-alcoholic steatohepatitis (NASH). Our findings indicate that LicoB is a specific NLRP3 inhibitor and a promising candidate for treating NLRP3 inflammasome-related diseases.

Tanshinone I specifically suppresses NLRP3 inflammasome activation by disrupting the association of NLRP3 and ASC.

BACKGROUND: Abnormal activation of NLRP3 inflammasome is related to a series of inflammatory diseases, including type 2 diabetes, gouty arthritis, non-alcoholic steatohepatitis (NASH), and neurodegenerative disorders. Therefore, targeting NLRP3 inflammasome is regarded as a potential therapeutic strategy for many inflammatory diseases. A growing number of studies have identified tanshinone I (Tan I) as a potential anti-inflammatory agent because of its good anti-inflammatory activity. However, its specific anti-inflammatory mechanism and direct target are unclear and need further study. METHODS: IL-1ß and caspase-1 were detected by immunoblotting and ELISA, and mtROS levels were measured by flow cytometry. Immunoprecipitation was used to explore the interaction between NLRP3, NEK7 and ASC. In a mouse model of LPS-induced septic shock, IL-1ß levels in peritoneal lavage fluid and serum were measured by ELISA. Liver inflammation and fibrosis in the NASH model were analyzed by HE staining and immunohistochemistry. RESULTS: Tan I inhibited the activation of NLRP3 inflammasome in macrophages, but had no effect on the activation of AIM2 or NLRC4 inflammasome. Mechanistically, Tan I inhibited NLRP3 inflammasome assembly and activation by targeting NLRP3-ASC interaction. Furthermore, Tan I exhibited protective effects in mouse models of NLRP3 inflammasome-mediated diseases, including septic shock and NASH. CONCLUSIONS: Tan I specifically suppresses NLRP3 inflammasome activation by disrupting the association of NLRP3 and ASC, and exhibits protective effects in mouse models of LPS-induced septic shock and NASH. These findings suggest that Tan I is a specific NLRP3 inhibitor and may be a promising candidate for treating NLRP3 inflammasome-related diseases.

Novel role for epalrestat: protecting against NLRP3 inflammasome-driven NASH by targeting aldose reductase.

BACKGROUND: Nonalcoholic steatohepatitis (NASH) is a progressive and inflammatory subtype of nonalcoholic fatty liver disease (NAFLD) characterized by hepatocellular injury, inflammation, and fibrosis in various stages. More than 20% of patients with NASH will progress to cirrhosis. Currently, there is a lack of clinically effective drugs for treating NASH, as improving liver histology in NASH is difficult to achieve and maintain through weight loss alone. Hence, the present study aimed to investigate potential therapeutic drugs for NASH. METHODS: BMDMs and THP1 cells were used to construct an inflammasome activation model, and then we evaluated the effect of epalrestat on the NLRP3 inflammasome activation. Western blot, real-time qPCR, flow cytometry, and ELISA were used to evaluate the mechanism of epalrestat on NLRP3 inflammasome activation. Next, MCD-induced NASH models were used to evaluate the therapeutic effects of epalrestat in vivo. In addition, to evaluate the safety of epalrestat in vivo, mice were gavaged with epalrestat daily for 14 days. RESULTS: Epalrestat, a clinically effective and safe drug, inhibits NLRP3 inflammasome activation by acting upstream of caspase-1 and inducing ASC oligomerization. Importantly, epalrestat exerts its inhibitory effect on NLRP3 inflammasome activation by inhibiting the activation of aldose reductase. Further investigation revealed that the administration of epalrestat inhibited NLRP3 inflammasome activation in vivo, alleviating liver inflammation and improving NASH pathology. CONCLUSIONS: Our study indicated that epalrestat, an aldose reductase inhibitor, effectively suppressed NLRP3 inflammasome activation in vivo and in vitro and might be a new therapeutic approach for NASH.

Polysaccharide extract from Isatidis Radix inhibits multiple inflammasomes activation and alleviate gouty arthritis.

The polysaccharide extract from Isatidis Radix exhibits potent antiinflammatory and antiviral activities, but the mechanism of Isatidis Radix polysaccharide (IRP) remains obscure. Herein, we reported that IRP blocked the activation of nod-like receptor pyrin domain-containing 3 (NLRP3) inflammasome, leading to the inhibiting of caspase-1 cleavage and IL-1ß secretion. Mechanistically, IRP did not inhibit NLRP3 inflammasome through suppressing mitochondrial reactive oxygen species (mtROS) production. However, IRP can significantly suppress the oligomerization of apoptosis-associated speck-like protein (ASC) and subsequently block the formation of inflammasome. Next, we evaluate the role of IRP in monosodium urate (MSU)-induced gout in vivo which is a NLRP3-associated disease. We also observed that oral administration of IRP can reduce the increased ankle thickness and the secretion of IL-1ß, IL-18, IL-6, TNF-α and MPO of the mouse ankle joints caused by MSU crystals. Furthermore, flow cytometry analysis highlighted a significant modulation of T helper 17 cells (Th17)/regulatory T cells (Treg) following IRP treatment in MSU induced gout. Overall, our findings suggest that IRP has comprehensive and potent antiinflammatory effects and provide a reasonable therapeutic strategy in preventing inflammasome-associated diseases, such as inflammatory gouty arthritis.

Establishment of an anti-inflammation-based bioassay for the quality control of the 13-component TCM formula (Lianhua Qingwen).

CONTEXT: Owing to the complexity of chemical ingredients in traditional Chinese medicine (TCM), it is difficult to maintain quality and efficacy by relying only on chemical markers. OBJECTIVE: Lianhua Qingwen capsule (LHQW) was selected as an example to discuss the feasibility of a bioassay for quality control. MATERIALS AND METHODS: Network pharmacology was used to screen potential targets in LHQW with respect to its anti-inflammatory effects. An in vitro cell model was used to validate the prediction. An anti-inflammatory bioassay was established for the quality evaluation of LHQW in 40 batches of marketed products and three batches of destructed samples. RESULTS: The tumor necrosis factor/interleukin-6 (TNF/IL-6) pathway via macrophage was selected as the potential target of LHQW. The IC50 value of LHQW on RAW 264.7 was 799.8 µg/mL. LHQW had significant inhibitory effects on the expression of IL-6 in a dose-dependent manner (p < 0.05). The anti-inflammatory biopotency of LHQW was calculated based on the inhibitory bioactivity on IL-6. The biopotency of 40 marketed samples ranged from 404 U/µg to 2171 U/µg, with a coefficient of variation (CV) of 37.91%. By contrast, the contents of forsythin indicated lower CV (28.05%) than the value of biopotency. Moreover, the biopotencies of destructed samples declined approximate 50%, while the contents of forsythin did not change. This newly established bioassay revealed a better ability to discriminate the quality variations of LHQW as compared to the routine chemical determination. CONCLUSIONS: A well-established bioassay may have promising ability to reveal the variance in quality of TCM.

Tryptanthrin suppresses multiple inflammasome activation to regulate NASH progression by targeting ASC protein.

BACKGROUND: The adaptor protein apoptosis-associated speck-like protein (ASC) containing a caspase recruitment domain (CARD) can be activated through pyrin domain (PYD) interactions between sensors and ASC, and through CARD interactions between caspase-1 and ASC. Although the majority of ternary inflammasome complexes depend on ASC, drugs targeting ASC protein remain scarce. After screening natural compounds from Isatidis Radixin, we found that tryptanthrin (TPR) could inhibit NLRP3-induced IL-1ß and caspase-1 production, but the underlying anti-inflammatory mechanisms remain to be elucidated. PURPOSE: The purpose of this study was to determine the impact of TPR on the NLRP3, NLRC4, and AIM2 inflammasomes and the underlying mechanisms. Additionally, the efficacy of TPR was analysed in the further course of methionine- and choline-deficient (MCD)-induced NASH and lipopolysaccharide (LPS)-induced sepsis models of mice. METHODS: In vitro studies used bone marrow-derived macrophages to assess the anti-inflammatory activity of TPR, and the techniques included western blot, testing of intracellular K+ and Ca2+, immunofluorescence, enzyme-linked immunosorbent assay (ELISA), co-immunoprecipitation, ASC oligomerization assay, surface plasmon resonance (SPR), and molecular docking. We used LPS-induced sepsis models and MCD-induced NASH models in vivo to evaluate the effectiveness of TPR in inhibiting inflammatory diseases. RESULTS: Our observations suggested that TPR could inhibit NLRP3, NLRC4, and AIM2 inflammasome activation. As shown in a mouse model of inflammatory diseases caused by MCD-induced NASH and LPS-induced sepsis, TPR significantly alleviated the progression of diseases. TPR interrupted the interactions between ASC and NLRP3/NLRC4/AIM2 in the co-immunoprecipitation experiment, and stable binding of TPR to ASC was also evident in SPR experiments. The underlying mechanisms of anti-inflammatory activities of TPR might be associated with targeting ASC, in particular, PYD domain of ASC. CONCLUSION: In general, the requirement for ASC in multiple inflammasome complexes makes TPR, as a novel broad-spectrum inflammasome inhibitor, potentially useful for treating a wide range of multifactorial inflammasome-related diseases.

Glycyrrhiza uralensis polysaccharides ameliorates cecal ligation and puncture-induced sepsis by inhibiting the cGAS-STING signaling pathway.

Ethnopharmacological relevance: G. uralensis Fisch. (Glycyrrhiza uralensis) is an ancient and widely used traditional Chinese medicine with good efficacy in clearing heat and detoxifying action. Studies suggest that Glycyrrhiza Uralensis Polysaccharides (GUP), one of the major components of G. uralensis, has anti-inflammatory, anti-cancer and hepatoprotective effects., but its exact molecular mechanism has not been explored in depth. Aim of the study: Objectives of our research are about exploring the anti-inflammatory role of GUP and the mechanisms of its action. Materials and methods: ELISA kits, Western blotting, immunofluorescence, quantitative real-time PCR, immunoprecipitation and DMXAA-mediated STING activation mice models were performed to investigate the role of GUP on the cGAS-STING pathway. To determine the anti-inflammatory effects of GUP, cecal ligation and puncture (CLP) sepsis models were employed. Results: GUP could effectively inhibit the activation of the cGAS-STING signaling pathway accompany by a decrease the expression of type I interferon-related genes and inflammatory factors in BMDMs, THP-1, and human PBMCs. Mechanistically, GUP does not affect the oligomerization of STING, but affects the interaction of STING with TBK1 and TBK1 with IRF3. Significantly, GUP had great therapeutic effects on DMXAA-induced agonist experiments in vivo as well as CLP sepsis in mice. Conclusion: Our studies suggest that GUP is an effective inhibitor of the cGAS-STING pathway, which may be a potential medicine for the treatment of inflammatory diseases mediated by the cGAS-STING pathway.

Compound Danshen Dripping Pill effectively alleviates cGAS-STING-triggered diseases by disrupting STING-TBK1 interaction.

BACKGROUND: The cyclic GMP-AMP synthase (cGAS)-stimulator of interferon (IFN) genes (STING) pathway is critical in the innate immune system and can be mobilized by cytosolic DNA. The various inflammatory and autoimmune diseases progression is highly correlated with aberrant cGAS-STING pathway activation. While some cGAS-STING pathway inhibitor were identified, there are no drugs that can be applied to the clinic. Compound Danshen Dripping Pill (CDDP) has been successfully used in clinic around the world, but the most common application is limited to cardiovascular disease. Therefore, the purpose of the present investigation was to examine whether CDDP inhibits the cGAS-STING pathway and could be used as a therapeutic agent for multiple cGAS-STING-triggered diseases. METHODS: BMDMs, THP1 cells or Trex1-/- BMDMs were stimulated with various cGAS-STING-agonists after pretreatment with CDDP to detect the function of CDDP on IFN-ß and ISGs productionn. Next, we detect the influence on IRF3 and P65 nuclear translocation, STING oligomerization and STING-TBK1-IRF3 complex formation of CDDP. Additionally, the DMXAA-mediated activation mice model of cGAS-STING pathway was used to study the effects of CDDP. Trex1-/- mice model and HFD-mediated obesity model were established to clarify the efficacy of CDDP on inflammatory and autoimmune diseases. RESULTS: CDDP efficacy suppressed the IRF3 phosphorylation or the generation of IFN-ß, ISGs, IL-6 and TNF-α. Mechanistically, CDDP did not influence the STING oligomerization and IRF3-TBK1 and STING-IRF3 interaction, but remarkably eliminated the STING-TBK1 interaction, ultimately blocking the downstream responses. In addition, we also clarified that CDDP could suppress cGAS-STING pathway activation triggered by DMXAA, in vivo. Consistently, CDDP could alleviate multi-organ inflammatory responses in Trex1-/- mice model and attenuate the inflammatory disorders, incleding obesity-induced insulin resistance. CONCLUSION: CDDP is a specifically cGAS-STING pathway inhibitor. Furthermore, we provide novel mechanism for CDDP and discovered a clinical agent for the therapy of cGAS-STING-triggered inflammatory and autoimmune diseases.

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-1ß (IL-1ß), 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.

Schisandrin C enhances type I IFN response activation to reduce tumor growth and sensitize chemotherapy through antitumor immunity.

With the advancing comprehension of immunology, an increasing number of immunotherapies are being explored and implemented in the field of cancer treatment. The cGAS-STING pathway, a crucial element of the innate immune response, has been identified as pivotal in cancer immunotherapy. We evaluated the antitumor effects of Schisandra chinensis lignan component Schisandrin C (SC) in 4T1 and MC38 tumor-bearing mice, and studied the enhancing effects of SC on the cGAS-STING pathway and antitumor immunity through RNA sequencing, qRT-PCR, and flow cytometry. Our findings revealed that SC significantly inhibited tumor growth in models of both breast and colon cancer. This suppression of tumor growth was attributed to the activation of type I IFN response and the augmented presence of T cells and NK cells within the tumor. Additionally, SC markedly promoted the cGAS-STING pathway activation induced by cisplatin. In comparison to cisplatin monotherapy, the combined treatment of SC and cisplatin exhibited a greater inhibitory effect on tumor growth. The amplified chemotherapeutic efficacy was associated with an enhanced type I IFN response and strengthened antitumor immunity. SC was shown to reduce tumor growth and increase chemotherapy sensitivity by enhancing the type I IFN response activation and boosting antitumor immunity, which enriched the research into the antitumor immunity of S. chinensis and laid a theoretical basis for its application in combating breast and colon cancer.

Network pharmacology-based strategy for predicting therapy targets of Ecliptae Herba on breast cancer.

Breast cancer is a prevalent malignancy affecting women globally, characterized by significant morbidity and mortality rates. Ecliptae Herba is a traditional herbal medicine commonly used in clinical practice, has recently been found to possess antitumor properties. In order to explore the underlying material basis and molecular mechanisms responsible for the anti-breast cancer effects of Ecliptae Herba, we used network pharmacology and experimental verification. UPLC-MS/MS was utilized to identify compounds present in Ecliptae Herba. The active components of Ecliptae Herba and its breast cancer targets were screened using public databases. Hub genes were identified using the STRING and Metascape database. The R software was utilized for visual analysis of GO and KEGG pathways. The affinity of the hub targets for the active ingredients was assessed by molecular docking analysis, which was verified by experimental assessment. A total of 178 targets were obtained from the 10 active components of Ecliptae Herba, while 3431 targets associated with breast cancer were screened. There were 144 intersecting targets between the components and the disease. Targets with a higher degree, namely EGFR and TGFB1, were identified through the hub subnetwork of PPI. GO and KEGG analyses revealed that Ecliptae Herba plays an important role in multiple cancer therapeutic mechanisms. Moreover, molecular docking results showed that the core components had good binding affinity with key targets. Finally, it was confirmed that TGF-ß1 might be a potential crucial target of Ecliptae Herba in the treatment of breast cancer by cytological experiments, and the TGF-ß1/Smad signaling pathway might be an important pathway for Ecliptae Herba to exert its therapeutic effects. This study elucidated the active ingredients, key targets, and molecular mechanisms of Ecliptae Herba in the treatment of breast cancer, providing a scientific foundation and therapeutic mechanism for the prevention and treatment of breast cancer with Traditional Chinese medicine.

Schizophrenia-Like Behaviors Arising from Dysregulated Proline Metabolism Are Associated with Altered Neuronal Morphology and Function in Mice with Hippocampal PRODH Deficiency.

Despite decades of research being conducted to understand what physiological deficits in the brain are an underlying basis of psychiatric diseases like schizophrenia, it has remained difficult to establish a direct causal relationship between neuronal dysfunction and specific behavioral phenotypes. Moreover, it remains unclear how metabolic processes, including amino acid metabolism, affect neuronal function and consequently modulate animal behaviors. PRODH, which catalyzes the first step of proline degradation, has been reported as a susceptibility gene for schizophrenia. It has consistently been shown that PRODH knockout mice exhibit schizophrenia-like behaviors. However, whether the loss of PRODH directly impacts neuronal function or whether such neuronal deficits are linked to schizophrenia-like behaviors has not yet been examined. Herein, we first ascertained that dysregulated proline metabolism in humans is associated with schizophrenia. We then found that PRODH was highly expressed in the oreins layer of the mouse dorsal hippocampus. By using AAV- mediated shRNA, we depleted PRODH expression in the mouse dorsal hippocampus and subsequently observed hyperactivity and impairments in the social behaviors, learning, and memory of these mice. Furthermore, the loss of PRODH led to altered neuronal morphology and function both in vivo and in vitro. Our study demonstrates that schizophrenia-like behaviors may arise from dysregulated proline metabolism due to the loss of PRODH and are associated with altered neuronal morphology and function in mice.

The role of NLRP3 inflammasome in psychotropic drug-induced hepatotoxicity.

Increased medical application of psychotropic drugs raised attention concerning their toxicological effects. In fact, more than 160 psychotropic drugs including antidepressants and antipsychotics, have been shown to cause liver side effects, but the underlying mechanisms are still poorly understood. Here, we discovered that fluoxetine, a common antidepressant, was specifically sensed by NLRP3 inflammasome, whose subsequent activation resulted in the maturation of caspase-1 and IL-1ß, as well as gasdermin D (GSDMD) cleavage, which could be completely abrogated by a selective NLRP3 inhibitor MCC950 or Nlrp3 knockout (Nlrp3-/-). Mechanistically, mitochondrial damage and the subsequent mitochondrial reactive oxygen species (mtROS) accumulation were crucial upstream signaling events in fluoxetine-triggered NLRP3 inflammasome activation. In fluoxetine hepatotoxicity models, mice showed the alterations of aminotransferase levels, hepatic inflammation and hepatocyte death in an NLRP3-dependent manner, and MCC950 pretreatment could reverse these side effects of fluoxetine. Notably, we also found that multiple antidepressants, such as amitriptyline, paroxetine, and imipramine, and antipsychotics, such as asenapine, could specifically trigger the NLRP3 inflammasome activation. Collectively, our findings implicate multiple psychotropic drugs may act as danger signals sensed by the NLRP3 inflammasome and result in hepatic injury.

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

Aristolochic acid (AA) is a group of structurally related compounds what have been used to treat various diseases in recent decades. Aristolochic acid I (AAI), an important ingredient, has been associated with tumorigenesis. Recently, some studies indicated that AAI could induce liver injury in mice of different age, but comprehensive mechanisms of AAI-induced differences in liver injury in various age groups have not yet been elucidated. This study aims to evaluate the causal relationship between AAI-induced liver injury and age based on neonatal mice and adult mice. A survival experiment indicated that all neonatal mice survived. Moreover, the adult mice in the high-dose AAI group all died, whereas half of the adult mice in the low-dose AAI group died. In observation experiments, AAI induced more severe liver injury in neonatal mice than adult mice under long-term than short-term exposure. Furthermore, integrated metabolomics and transcriptomics indicated that AAI disturbing steroid hormone biosynthesis, arachidonic acid metabolism, the drug metabolism-cytochrome P450 pathway and glycerophospholipid metabolism induced neonatal mice liver injury. The important role of age in AAI-induced liver injury was illustrated in our study. This study also lays a solid foundation for scientific supervision of AA safety.

Chemical Exchange Saturation Transfer (CEST) Signal at -1.6 ppm and Its Application for Imaging a C6 Glioma Model.

The chemical exchange saturation transfer (CEST) signal at -1.6 ppm is attributed to the choline methyl on phosphatidylcholines and results from the relayed nuclear Overhauser effect (rNOE), that is, rNOE(-1.6). The formation of rNOE(-1.6) involving the cholesterol hydroxyl is shown in liposome models. We aimed to confirm the correlation between cholesterol content and rNOE(-1.6) in cell cultures, tissues, and animals. C57BL/6 mice (N = 9) bearing the C6 glioma tumor were imaged in a 7 T MRI scanner, and their rNOE(-1.6) images were cross-validated through cholesterol staining with filipin. Cholesterol quantification was obtained using an 18.8-T NMR spectrometer from the lipid extracts of the brain tissues from another group of mice (N = 3). The cholesterol content in the cultured cells was manipulated using methyl-ß-cyclodextrin and a complex of cholesterol and methyl-ß-cyclodextrin. The rNOE(-1.6) of the cell homogenates and their cholesterol levels were measured using a 9.4-T NMR spectrometer. The rNOE(-1.6) signal is hypointense in the C6 tumors of mice, which matches the filipin staining results, suggesting that their tumor region is cholesterol deficient. The tissue extracts also indicate less cholesterol and phosphatidylcholine contents in tumors than in normal brain tissues. The amplitude of rNOE(-1.6) is positively correlated with the cholesterol concentration in the cholesterol-manipulated cell cultures. Our results indicate that the cholesterol dependence of rNOE(-1.6) occurs in cell cultures and solid tumors of C6 glioma. Furthermore, when the concentration of phosphatidylcholine is carefully considered, rNOE(-1.6) can be developed as a cholesterol-weighted imaging technique.

Schisandra chinensis Oil Attenuates Aristolochic Acid I-Induced Nephrotoxicity in vivo and in vitro.

OBJECTIVE: To investigate the protective effects of Schisandra chinensis oil (SCEO) against aristolochic acid I (AA I)-induced nephrotoxicity in vivo and in vitro and elucidate the underlying mechanism. METHODS: C57BL/6 mice were randomly divided into 5 groups according to a random number table, including control group, AA I group, and AA I +SCEO (0.25, 0.5 and 1 g/kg) groups (n=5 per group). Pretreatment with SCEO was done for 2 days by oral administration, while the control and AA I groups were treated with sodium carboxymethyl cellulose. Mice of all groups except for the control group were injected intraperitoneally with AA I (5 mg/kg) from day 3 until day 7. Histopathological examination and apoptosis of kidney tissue were observed by hematoxylin and eosin and TdT-mediated dUTP nick-end labeling (TUNEL) staining, respectively. The levels of serum alanine aminotransferase (ALT), aspartate aminotransferase (AST), blood urea nitrogen (BUN), and serum creatinine (SCr), as well as renal malondialdehyde (MDA), glutathione, r-glutamyl cysteingl+glycine (GSH), and superoxide dismutase (SOD) were analyzed using enzyme-linked immunosorbent assay (ELISA). Expressions of hepatic cytochrome P450 1A1 (CYP1A1), CYP1A2, and nad(p)hquinonedehydrogenase1 (NQO1) were analyzed using ELISA, quantitative real-time polymerase chain reaction (qPCR) and Western blot, respectively. In vitro, SCEO (40 µ g/mL) was added 12 h before treatment with AA I (40 µ mol/mL for 48 h) in human renal proximal tubule cell line (HK-2), then apoptosis and reactive oxygen species (ROS) were analyzed by flow cytometry. RESULTS: SCEO 0.5 and 1 g/kg ameliorated histopathological changes and TUNEL+ staining in the kidney tissues of mice with AA I-induced nephrotoxicity, and reduced serum levels of ALT, AST, BUN and SCr (P<0.01 or P<0.05). SCEO 0.5 and 1 g/kg alleviated the ROS generation in kidney, containing MDA, GSH and SOD (P<0.01 or P<0.05). SCEO 1 g/kg increased the expressions of CYP1A1 and CYP1A2 and decreased NQO1 level in the liver tissues (P<0.01 or P<0.05). Besides, in vitro studies also demonstrated that SCEO 40 µ g/mL inhibited apoptosis and ROS generation (P<0.05 or P<0.01). CONCLUSIONS: SCEO can alleviate AA I-induced kidney damage both in vivo and in vitro. The protective mechanism may be closely related to the regulation of metabolic enzymes, thereby inhibiting apoptosis and ROS production.

Isoxanthohumol, a component of Sophora flavescens, promotes the activation of the NLRP3 inflammasome and induces idiosyncratic hepatotoxicity.

ETHNOPHARMACOLOGICAL RELEVANCE: Sophora flavescens is a traditional Chinese medicine commonly used in clinical practice, which has the effects of clearing away heat and dampness. Unfortunately, it has been reported that Sophora flavescens and its preparation may cause liver damage to a certain extent, but the exact mechanism is not clear. AIM OF THE STUDY: To assess the safety and risk of Sophora flavescens and to elucidate the relationship between Idiosyncratic drug-induced liver injury (IDILI) and the NOD-like receptor family protein 3 (NLRP3) inflammasome. MATERIALS AND METHODS: Western blot, Caspase-Glo® 1 Inflammasome Assay, ELISA kits, Flow cytometry and FLIPRT Tetra system were used to study the effect of isoxanthohumol (IXN) on the activation of NLRP3 inflammasome and its mechanism. Combined with the lipopolysaccharide-mediated susceptibility IDILI model in mice to evaluate the hepatotoxicity of IXN. RESULTS: IXN facilitates the activation of caspase-1 and secretion of interleukin (IL)-1ß triggered by adenosine triphosphate (ATP), nigericin but not those induced by silicon dioxide and poly (I:C). Furthermore, the activation of NLR-family CARD-containing protein 4 (NLRC4) and the absent in melanoma 2 (AIM2) was not affected by IXN. Mechanistically, IXN promotes NLRP3-dependent apoptosis-associated speck-like protein containing a C-terminal caspase recruitment domain (ASC) oligomerization and the generation of mitochondrial reactive oxygen species (mtROS) triggered by ATP. The in vivo data showed that non-hepatotoxic doses of IXN resulted in increased levels of glutamate-pyruvate transaminase, glutamate-oxaloacetate transaminase, tumor necrosis factor and IL-1ß in the serum and showed increased liver inflammation in the susceptible IDILI model mediated by lipopolysaccharide. CONCLUSIONS: These results show that IXN enhances NLRP3 inflammasome activation by promoting the accumulation of ATP-induced mtROS and ASC oligomerization to cause IDILI, indicating that IXN may be a risk factor for liver injury caused by the clinical use of Sophora flavescens.

Discovery of bakuchiol as an AIM2 inflammasome activator and cause of hepatotoxicity.

ETHNOPHARMACOLOGICAL RELEVANCE: Psoralea corylifolia (P. corylifolia Linn.) is a traditional Chinese medicinal plant that exhibits significant aphrodisiac, diuretic, and anti-rheumatic effects. However, it has been reported to cause hepatic injury, but the precise mechanisms remain unclear. AIM OF THE STUDY: To evaluate the safety and risk of P. corylifolia and to elucidate the underlying mechanisms of drug-induced liver injury. MATERIALS AND METHODS: Western blotting, enzyme-linked immunosorbent assay (ELISA), immunofluorescence, quantitative polymerase chain reaction (Q-PCR), and flow cytometry were used to explore the effect of bakuchiol (Bak), one of the most abundant and biologically active components of P. corylifolia, on the AIM2 inflammasome activation and the underlying mechanism. Furthermore, we used the lipopolysaccharides (LPS)-induced drug-induced liver injury (DILI) susceptible mice model to study the Bak-mediated hepatotoxicity. RESULTS: Bak induced the maturation of caspase-1 P20, and significantly increased the expression of IL-1ß and TNF-α (P < 0.0001) compared with the control group. Moreover, compared to the Bak group, knockdown of AIM2 inhibited Bak-induced caspase-1 maturation and significantly decreased the production of IL-1ß and TNF-α, but knockout of NLRP3 had no effect. Mechanistically, Bak-induced AIM2 inflammasome activation is involved in mitochondrial damage, mitochondrial DNA (mtDNA) release, and subsequent recognition of cytosolic mtDNA. Our in vivo data showed that co-exposure to LPS and non-hepatotoxic doses of Bak significantly increased the levels of ALT, AST, IL-1ß, TNF-α, and IL-18, indicating that Bak can induce severe liver inflammation (P < 0.005). CONCLUSIONS: The result shows that Bak activates the AIM2 inflammasome by inducing mitochondrial damage to release mtDNA, and subsequently binds to the AIM2 receptor, indicating that Bak may be a risk factor for P. corylifolia-induced hepatic injury.

Dihydrotanshinone I Specifically Inhibits NLRP3 Inflammasome Activation and Protects Against Septic Shock In Vivo.

The abnormal activation of the NLRP3 inflammasome is closely related to the occurrence and development of many inflammatory diseases. Targeting the NLRP3 inflammasome has been considered an efficient therapy to treat infections. We found that dihydrotanshinone I (DHT) specifically blocked the canonical and non-canonical activation of the NLRP3 inflammasome. Nevertheless, DHT had no relation with the activation of AIM2 or the NLRC4 inflammasome. Further study demonstrated that DHT had no influences on potassium efflux, calcium flux, or the production of mitochondrial ROS. We also discovered that DHT suppressed ASC oligomerization induced by NLRP3 agonists, suggesting that DHT inhibited the assembly of the NLRP3 inflammasome. Importantly, DHT possessed a significant therapeutic effect on NLRP3 inflammasome-mediated sepsis in mice. Therefore, our results aimed to clarify DHT as a specific small-molecule inhibitor for the NLRP3 inflammasome and suggested that DHT can be used as a potential drug against NLRP3-mediated diseases.

Germacrone Attenuates Hepatic Stellate Cells Activation and Liver Fibrosis via Regulating Multiple Signaling Pathways.

Liver fibrosis is an abnormal proliferation of connective tissue in the liver caused by various pathogenic factors. Chronic liver injury leads to release of inflammatory cytokines and reactive oxygen species (ROS) from damaged hepatocytes, which activates hepatic stellate cells (HSCs) to secrete extracellular matrix proteins, thereby leading to fibrosis. Thus, inhibition of hepatocyte injury and HSC activation, and promotion of apoptosis of activated HSCs are important strategies for prevention of liver fibrosis. In this study, we showed that the germacrone (GER), the main component in the volatile oil of zedoary turmeric, inhibited hepatic fibrosis by regulating multiple signaling pathways. First, GER improved the cell survival rate by inhibiting the production of ROS after hepatocyte injury caused by acetaminophen (APAP). In addition, GER inhibited the activation of HSCs and expression of collagen I by blocking TGF-ß/Smad pathway in LX-2 cells. However, when the concentration of GER was higher than 60 µM, it specifically induced HSCs apoptosis by promoting the expression and activation of apoptosis-related proteins, but it had no effect on hepatocytes. Importantly, GER significantly attenuated the methionine- and choline-deficient (MCD) diet-induced liver fibrosis by inhibiting liver injury and the activation of HSCs in vivo. In summary, GER can not only protect hepatocytes by reducing ROS release to avoid the liver injury-induced HSC activation, but also directly inhibit the activation and survival of HSCs by regulating TGF-ß/Smad and apoptosis pathways. These results demonstrate that GER can be used as a potential therapeutic drug for the treatment of liver fibrosis.