A comparative study on pharmacokinetics and tissue distribution of 5-hydroxy-4-methoxycanthin-6-one and its metabolite in normal and dextran sodium sulfate-induced colitis rats by HPLC-MS/MS

Trichodelphinine A alleviates pulmonary fibrosis by inhibiting collagen synthesis via NOX4-ARG1/TGF-β signaling pathway

BACKGROUND

Pulmonary fibrosis, a progressive and fatal lung disease with no effective treatment medication, is characterized by lung remodeling and fibroblastic foci caused by an oxidative imbalance with an overloading deposition of collagen. Trichodelphinine A, a hetisine-type C20-diterpenoid alkaloid, was found anti-fibrotic activity in vitro, but its effect and mechanism on pulmonary fibrosis still unknown.

PURPOSE

Our study aimed to investigate and validate the anti-fibrotic properties of trichodelphinine A in pulmonary fibrosis animals induced by bleomycin (BLM), and its mechanism whether via NOX4-ARG1/TGF-β signaling pathway.

METHODS

The anti-fibrotic effects of trichodelphinine A were evaluated using BLM-induced rats through indicators of lung histopathology and collagen synthesis. Dynamic metabolomics evaluated the metabolic disorder and therapeutic effect of trichodelphinine A. The interaction between trichodelphinine A and NOX4 receptor was confirmed using CETSA and molecular dynamics experiments. Molecular biology experiments were conducted in NOX4 gene knockout mice to investigate the intervention effect of trichodelphinine A.

RESULTS

Trichodelphinine A could suppress histopathologic changes, collagen deposition and proinflammatory cytokine release pulmonary fibrosis in bleomycin induced rats. Dynamic metabolomics studies revealed that trichodelphinine A could correct endogenous metabolic disorders of arachidonic acid, arginine and proline during fibrosis development, which revealed that the regulation of oxidative stress and amino acid metabolism targeting NOX4 and ARG1 may be the main pharmacological mechanisms of trichodelphinine A on pulmonary fibrosis. We further determined that trichodelphinine A inhibited over oxidative stress and collagen deposition by suppressing Nrf2-keap1 and ARG1-OAT signaling pathways, respectively. Molecular dynamics studies showed that trichodelphinine A was directly binds with NOX4, in which PHE354 and THR355 residues of NOX4 are critical binding sites for trichodelphinine A. Mechanistic validation in cells or mice with NOX4 knockout or silencing suggested that the anti-fibrotic effects of trichodelphinine A depended on inhibition of NOX4 to suppress ARG1/OAT activation and TGF-β/Smads signaling pathway.

CONCLUSION

Collectively, our findings indicate a powerful anti-fibrotic function of trichodelphinine A in pulmonary fibrosis via targeting NOX4. NOX4 mediates the activation of ARG1/OAT to regulate arginase-proline metabolism, and promotes TGF-β/Smads signaling pathway, thereby affecting the collagen synthesis in pulmonary fibrosis, which is a novel finding and indicates that inhibition of NOX4 is a novel therapeutic strategy for pulmonary fibrosis.

Therapeutic interventions target the NLRP3 inflammasome in ulcerative colitis: Comprehensive study

One of the significant health issues in the world is the prevalence of ulcerative colitis (UC). UC is a chronic disorder that mainly affects the colon, beginning with the rectum, and can progress from asymptomatic mild inflammation to extensive inflammation of the entire colon. Understanding the underlying molecular mechanisms of UC pathogenesis emphasizes the need for innovative therapeutic approaches based on identifying molecular targets. Interestingly, in response to cellular injury, the NLR family pyrin domain containing 3 (NLRP3) inflammasome is a crucial part of the inflammation and immunological reaction by promoting caspase-1 activation and the release of interleukin-1β. This review discusses the mechanisms of NLRP3 inflammasome activation by various signals and its regulation and impact on UC.

Nigakinone alleviates DSS-induced experimental colitis via regulating bile acid profile and FXR/NLRP3 signaling pathways

The correlation of bile acid (BA) metabolism disorder with the pathogenesis of ulcerative colitis (UC) is realized nowadays. Farnesoid X receptor (FXR), a controller for BA homeostasis and inflammation, is a promising target for UC therapy. Nigakinone has potential therapeutic effects on colitis. Herein, we investigated the anti-UC effects and mechanism of nigakinone in colitic animals induced by dextran sulfate sodium (DSS). The related targets involved in the nucleotide-binding oligomerization domain, leucine-rich repeat, and pyrin domain-containing 3 (NLRP3) signaling pathway were measured. BA-targeted metabolomics was employed to reveal the regulatory effects of nigakinone on BA profile in colitis, while expressions of FXR and its mediated targets referring to BA enterohepatic circulation were determined. The critical role of FXR in the treatment of nigakinone for colitis was studied via molecule-docking, dual-luciferase reporter® (DLR™) assays, FXR silencing cells, and FXR knockout mice. Results showed nigakinone attenuated DSS-induced colitis symptoms, including excessive inflammatory response by NLRP3 activation, and injury of the intestinal mucosal barrier. Nigakinone regulated BA disorders by controlling cholesterol hydroxylase and transporters mediated by FXR, then decreased BA accumulation in colon. Molecular-docking and DLR™ assays indicated FXR might be a target of nigakinone. In vitro, nigakinone restrained BA-induced inflammation and cell damage via FXR activation and inhibition of inflammatory cytokines. However, ameliorating effects of nigakinone on colitis were suppressed by FXR knockout or silencing in vivo or in vitro. Taken together, nigakinone ameliorated experimental colitis via regulating BA profile and FXR/NLRP3 signaling pathway.

Pharmacokinetic Study of Four Major Bioactive Components of Liandan Xiaoyan Formula in Ulcerative Colitis and Control Rats Using UPLC-MS/MS

Liandan Xiaoyan Formula (LXF), a classic Traditional Chinese medicine (TCM) formula, is composed of two Chinese herbal medicines for treating bowel disease under the TCM theory. This study aimed to develop a rapid, stable, sensitive, and reliable method based on ultra-high performance liquid chromatography-tandem mass spectrometry (UPLC-MS/MS) to simultaneously determine four major bioactive components of LXF (andrographolide, dehydroandrographolide, 1-methoxicabony-β-carboline, 4-methoxy-5-hydroxy-canthin-6-one) in rat serum and evaluate the pharmacokinetic characteristics of LXF in ulcerative colitis (UC) and control rats. After pretreating by protein precipitation with methanol, separation was performed on a UPLC C18 column using gradient elution with a mobile phase consisting of acetonitrile and 0.1% formic acid at a flowing rate of 0.4 ml/min. Detection was performed on Triple-TOF™ 5600 mass spectrometry set at the positive ionization and multiple reaction monitoring (MRM) mode. The validated method showed good linearity (R² ≥ 0.9970), the intra- and inter-day accuracy were within ±11.58%, whereas the intra- and inter-day precision were less than 13.79%. This method was validated and applied to compare the pharmacokinetic profiles of the analytes in serum of UC induced by dextran sulphate sodium (DSS) and control rats after oral administration of LXF. The results showed that four major bioactive components of LXF were quickly absorbed after oral administration in both groups, with higher exposure levels in the UC group. This relationship between the active ingredients’ pharmacokinetic properties provided essential scientific information for applying LXF in clinical.

Canthin-6-one (CO) from Picrasma quassioides (D.Don) Benn. ameliorates lipopolysaccharide (LPS)-induced astrocyte activation and associated brain endothelial disruption

BACKGROUND

Canthin-6-one (CO) is an active ingredient found in Picrasma quassioides (D.Don) Benn. (PQ) that displays various biological activities including anti-inflammatory properties. Several studies reported PQ displayed neuroprotective activities, but its effects on astrocytes have not yet been investigated. Astrocytes are crucial regulators of neuroinflammatory responses under pathological conditions in the central nervous system (CNS). Proinflammatory astrocytes can induce the blood-brain barrier (BBB) breakdown, which plays a key role in the progression of neurodegenerative disorder (ND).

PURPOSE

This study aims to investigate the anti-neuroinflammatory effects of CO in LPS-induced astrocyte activation and its underlying mechanisms in protecting the blood-brain barrier (BBB) in vitro.

METHODS

Mouse astrocytes (C8-D1A) were activated with lipopolysaccharide (LPS) with or without CO pretreatment. Effects of CO on astrocyte cell viability, secretions of tumor necrosis factor-α (TNF-α), interleukin-6 (IL-6), interleukin-1β (IL-1β) and nitric oxide (NO) were determined. Intracellular transcriptions and translations of proinflammatory mediators, molecular signaling, [Ca²⁺] and the levels of reactive oxygen species (ROS) were evaluated by RT-PCR, western blotting, and flow cytometry, respectively. Astrocyte-conditioned medium (ACM) was further prepared for incubating endothelial monolayer (bEnd.3) grown on transwell. Endothelial disruptions were evaluated by transendothelial electrical resistance (TEER), FITC-dextran permeability and monocyte adhesion assays. Endothelial tight junctions (TJs) and molecular signaling pathways were evaluated by immunofluorescence staining and western blotting.

RESULTS

CO attenuated LPS-induced expression of astrocytic proinflammatory mediators (TNF-α, IL-1β, IL-6, NO) and inhibited deleterious molecular activities including inducible nitric oxide synthase (iNOS), p-NFκB and p-STAT3 in astrocytes. Incubation of ACM collected from CO-treated astrocytes significantly ameliorated endothelial disruptions, reduced expressions of endothelial cytokine receptors (IL-6R, gp130 (IL-6RB), TNFR and IL-1R), suppressed proinflammatory pathways, MAPKs (p-AKT, p-MEK, p-ERK, p-p38, p-JNK) and p-STAT3, restored endothelial stabilizing pathways (p-Rac 1) and upregulated beneficial endothelial nitric oxide synthase (eNOS).

CONCLUSION

Our study demonstrates for the first time CO exhibited potent protective effects against astrocyte-mediated proinflammatory responses and associated endothelial barrier disruptions.

In-depth comparison of the metabolic and pharmacokinetic behaviour of the structurally related synthetic cannabinoids AMB-FUBINACA and AMB-CHMICA in rats

Synthetic cannabinoids receptor agonists (SCRAs) are often almost completely metabolised, and hence their pharmacokinetics should be carefully evaluated for determining the most adequate biomarker in toxicological analysis. Two structurally related SCRAs, AMB-FUBINACA and AMB-CHMICA, were selected to evaluate their in vivo metabolism and pharmacokinetics using male Sprague-Dawley rats. Brain, liver, kidney, blood (serum) and urine samples were collected at different times to assess the differences in metabolism, metabolic reactions, tissue distribution and excretion. Both compounds experimented O-demethyl reaction, which occurred more rapidly for AMB-FUBINACA. The parent compounds and O-demethyl metabolites were highly bioaccumulated in liver, and were still detected in this tissue 48 h after injection. The different indazole/indole N-functionalisation produced diverse metabolic reactions in this moiety and thus, different urinary metabolites were formed. Out of the two compounds, AMB-FUBINACA seemed to easily cross the blood-brain barrier, presenting higher brain/serum concentrations ratio than AMB-CHMICA.

Synthetic cannabinoids are amongst the most widely used psychoactive drugs which are tightly controlled by government agencies around the world. Here, pharmacokinetics of two synthetic cannabinoids in rats are evaluated along with their metabolites and tissue distribution, aiding in identifying distinct biomarkers that reflect the consumption of synthetic cannabinoids based on the tissue.

Pharmacokinetic study of seven bioactive components of Xiaoyan Lidan Formula in cholestatic and control rats using UPLC-MS/MS

A rapid, sensitive, and reliable ultra-high performance liquid chromatography-tandem mass spectrometry (UPLC-MS/MS) method has been developed to simultaneously determine the major bioactive components of Xiaoyan Lidan Formula (XYLDF) in rat plasma, using sulfamethoxazole as the internal standard (IS). The seven major bioactive components are andrographolide, dehydroandrographolide, enmein, 1-methoxicabony-β-carboline, 4,5-dimethoxy-canthin-6-one, 4-methoxy-5-hydroxy-canthin-6-one, and 1-hydroxymethyl-β-carboline. After pretreating by protein precipitation with methanol, separation was performed on a UPLC C18 column using gradient elution with a mobile phase consisting of acetonitrile and 0.1% formic acid at a flowing rate of 0.7 mL/min. Detection was performed on TSQ Quantum mass spectrometry set at the positive/negative ionization and multiple reaction monitoring (MRM) mode. The intra- and inter-day precision were less than 9.8%, whereas the intra- and inter-day accuracy were within ± 13.4%. The method was validated and applied to compare the pharmacokinetic profiles of the analytes in serum of Alpha-naphthylisothiocyanate (ANIT)-induced cholestasis and control rats after oral administration of XYLDF. The results showed remarkable differences in pharmacokinetic properties of the analytes between cholestatic (model) and control groups, thereby providing essential scientific information for better understanding of mechanism of XYLDF and a reference for its clinical applications.