Circadian clock regulates metabolism and toxicity of Fuzi(lateral root of Aconitum carmichaeli Debx) in mice

The acute toxic effect of Chinese medicine Fuzi is exacerbated in kidney yang deficiency mice due to metabolic difference

ETHNOPHARMACOLOGICAL RELEVANCE

The proper application of toxic medicines is one of the characteristics of traditional Chinese medicines, and the use of traditional Chinese medicines follows the principle of dialectical treatment. It is necessary to combine different "syndrome" or "disease" states with the toxicity of traditional Chinese medicines to form a reliable toxicity evaluation system. Fuzi, the lateral root of Aconitum carmichaelii Debx, is recognized as a panacea for kidney yang deficiency syndrome, however, its toxic effects significantly limit its clinical application.

AIM OF THE STUDY

Herein, our research aimed to explore the toxic effects of Fuzi on syndrome models, and tried to reveal the underlying mechanisms.

MATERIALS AND METHODS

Firstly, the mouse model of kidney yang deficiency syndrome was established through intramuscular injection of 25 mg/kg hydrocortisone per day for 10 consecutive days. Then, the acute toxicity of Fuzi in normal mice and kidney yang deficiency model mice was explored. Finally, the plasma metabolite concentrations and liver CYP3A4 enzyme activity were analyzed to reveal the possible mechanisms of the different pharmacological and toxicological effects of Fuzi in individuals with different physical constitutions.

RESULTS

It was found that the treatment with Fuzi (138 g/kg) had serious toxic effects on kidney yang deficiency mice, leading to the death of 80% of the mice, whereas it showed no lethal toxicity in normal mice. This indicates that Fuzi induced greater toxicity in kidney yang deficiency mice than in normal ones. The liver CYP3A4 enzyme activity in kidney yang deficiency mice was decreased by 20% compared to the controls, resulting in slower metabolism of the toxic diester diterpenoid alkaloids in Fuzi.

CONCLUSION

In conclusion, our study showed that changes of the metabolic enzyme activity in individuals with different syndromes led to different toxic effects of Chinese medicines, emphasizing the crucial importance of considering individual physical syndromes in the clinical application of traditional Chinese medicine, and the significance of conducting safety evaluations and dose predictions on animal models with specific syndromes for traditional Chinese medicines.

Circadian control of ConA-induced acute liver injury and inflammatory response via Bmal1 regulation of Junb

Background & Aims

Circadian rhythms play significant roles in immune responses, and many inflammatory processes in liver diseases are associated with malfunctioning molecular clocks. However, the significance of the circadian clock in autoimmune hepatitis (AIH), which is characterised by immune-mediated hepatocyte destruction and extensive inflammatory cytokine production, remains unclear.

Methods

We tested the difference in susceptibility to the immune-mediated liver injury induced by concanavalin A (ConA) at various time points throughout a day in mice and analysed the effects of global, hepatocyte, or myeloid cell deletion of the core clock gene, Bmal1 (basic helix-loop-helix ARNT-like 1), on liver injury and inflammatory responses. Multiple molecular biology techniques and mice with macrophage-specific knockdown of Junb, a Bmal1 target gene, were used to investigate the involvement of Junb in the circadian control of ConA-induced hepatitis.

Results

The susceptibility to ConA-induced liver injury is highly dependent on the timing of ConA injection. The treatment at Zeitgeber time 0 (lights on) triggers the highest mortality as well as the severest liver injury and inflammatory responses. Further study revealed that this timing effect was driven by macrophage, but not hepatocyte, Bmal1. Mechanistically, Bmal1 controls the diurnal variation of ConA-induced hepatitis by directly regulating the circadian transcription of Junb and promoting M1 macrophage activation. Inhibition of Junb in macrophages blunts the administration time-dependent effect of ConA and attenuates liver injury. Moreover, we demonstrated that Junb promotes macrophage inflammation by regulating AKT and extracellular signal-regulated kinase (ERK) signalling pathways.

Conclusions

Our findings uncover a critical role of the Bmal1-Junb-AKT/ERK axis in the circadian control of ConA-induced hepatitis and provide new insights into the prevention and treatment of AIH.

Impact and Implications

This study unveils a critical role of the Bmal1-Junb-AKT/ERK axis in the circadian control of ConA-induced liver injury, providing new insights into the prevention and treatment of immune-mediated hepatitis, including autoimmune hepatitis (AIH). The findings have scientific implications as they enhance our understanding of the circadian regulation of immune responses in liver diseases. Furthermore, clinically, this research offers opportunities for optimising treatment strategies in immune-mediated hepatitis by considering the timing of therapeutic interventions.

Recent advances in circadian-regulated pharmacokinetics and its implications for chronotherapy

Dependence of pharmacokinetics and drug effects (efficacy and toxicity) on dosing time has long been recognized. However, significant progress has only recently been made in our understanding of circadian rhythms and their regulation on drug pharmacokinetics, efficacy and toxicity. This review will cover the relevant literature and a series of publications from our work summarizing the effects of circadian rhythms on drug pharmacokinetics, and propose that the influence of circadian rhythms on pharmacokinetics are ultimately translated into therapeutic effects and side effects of drugs. Evidence suggests that daily rhythmicity in expression of drug-metabolizing enzymes and transporters necessary for drug ADME (absorption, distribution, metabolism and excretion) are key factors determining circadian pharmacokinetics. Newly discovered mechanisms for circadian control of the enzymes and transporters are covered. We also discuss how the rhythms of drug-processing proteins are translated into circadian pharmacokinetics and drug chronoefficacy/chronotoxicity, which has direct implications for chronotherapy. More importantly, we will present perspectives on the challenges that are still needed for a breakthrough in translational research. In addition, knowledge of the circadian influence on drug disposition has provided new possibilities for novel pharmacological strategies. Careful application of pharmacokinetics-based chronotherapy strategies can improve efficacy and reduce toxicity. Circadian rhythm-mediated metabolic and transport strategies can also be implemented to design drugs.

Metabolic Behaviors of Aconitum Alkaloids in Different Concentrations of Aconiti Lateralis Radix Praeparata and Effects of Aconitine in Healthy Human and Long QT Syndrome Cardiomyocytes

Aconiti Lateralis Radix Praeparata (Fu Zi) is the processed lateral root of Aconitum carmichaelii Debx, which is widely used in emergency clinics. Poisoning incidents and adverse reactions occur with the improper intake of Fu Zi. Metabolic characteristics of aconitum alkaloids of Fu Zi may vary, and the effects of Fu Zi in healthy and Long QT syndrome (LQTS) patients is unknown. In this experiment, 24 Sprague Dawley rats were randomly divided into three groups: 2.0, 1.0, and 0.5 g/kg dose groups, and blood samples were collected after the oral administration of Fu Zi extract. We used an ultra-high performance liquid chromatography-tandem mass spectrometry system to detect the concentrations of six aconitum alkaloids. Cell toxicity, calcium imaging, and patch-clamp recordings of human induced pluripotent stem cells-cardiomyocytes (hiPSC-CMs) of aconitine in healthy and LQTS were observed. We found that the AUC(0–48h), Cmax, and t1/2 of the six compounds increased with the multiplicative dosages; those in the high group were significantly higher than those in the low group. Aconitine concentration-dependently decreased the amplitude, which has no significant effect on the cell index of normal hiPSC-CMs. Aconitine at 5.0 μM decreased the cell index between 5–30 min for LQTS hiPSC-CMs. Meanwhile, aconitine significantly increased the frequency of calcium transients in LQTS at 5 μM. Aconitine significantly shortened the action potential duration of human cardiomyocytes in both normal and LQTS groups. These results show metabolic behaviors of aconitum alkaloids in different concentrations of Fu Zi and effects of aconitine in healthy and LQTS patients.

Pharmacokinetics-based Chronotherapy

Dosing time-dependency of pharmacokinetics (or chronopharmacokinetics) has been long recognized. Studies in recent years have revealed that diurnal rhythmicity in expression of drug-metabolizing enzymes and transporters (DMETs) are key factors determining chronopharmacokinetics. In this article, we briefly summarize current knowledge with respect to circadian mechanisms of DMETs and discuss how rhythmic DMETs are translated to drug chronoeffects. More importantly, we present our perspectives on pharmacokinetics-based chronotherapy.

[Speciality of restoring the psychophysiological parameters of laboratory rats with the help of balneological procedures during the periods of equinox]

Currently methods development for restoring physiological functions and increasing the adaptive capabilities of the body after prolonged stress exposure of various genesis is an urgent problem in the field of balneology and physiotherapy. It is known that the adaptive potential of the organism is not the same in different seasons of the year. In this regard, it becomes necessary to take into account the seasonality factor when carrying out recreational activities.

PURPOSE OF THE STUDY

To perform a comparative study of balneotherapeutic procedures effectiveness in the form of water and antler baths in relation to the restoration of the psychophysiological parameters of laboratory rats after a consistent stressful effect of light desynchronosis and physical activity to a state of complete fatigue during autumn and spring equinoxes.

MATERIAL AND METHODS

The experiment was carried out during the periods of the spring and autumn equinoxes on 160 male Wistar rats weighing 220-250 g. In each season, the animals were divided into 8 groups of 10 individuals. Two groups were in natural lighting conditions. Animals of the 1st group (intact) were not exposed to experimental influences; rats of the 2nd group were exposed to physical activity in the form of a swimming test until complete fatigue for 5 days in a row in the morning; animals of groups 3-8 were exposed to stress loads in the form of 10-day light desynchronosis (light or dark deprivation) followed by physical activity. In the 4-th, 5-th, 7-th and 8-th groups, post-experimental post-stress recovery programs were carried out using water baths (groups 4 and 7) and baths with drug «Pantovanna» (groups 5 and 8). After the completion of exposures, the animals were tested in the «open field» according to the standard method. The level of corticosterone in the blood serum was determined by ELISA.

RESULTS

It was found that in laboratory rats sensitivity to stressful influences - light desynchronosis followed by physical activity to the point of fatigue, as well as active post-stress recovery were determined by the nature of desynchronosis and the season of the year. The stress load was accompanied by a phase of exhaustion during the spring equinox and by a phase of anxiety during the autumn equinox. In the spring, antler baths as a procedure for active post-stress recovery were ineffective; in autumn, they had a normalizing effect on the level of corticosterone and behavior only after dark deprivation.

CONCLUSION

The conducted experiment indicates the need to take into account the season of the year and the direction of the transmeridian flight to sanatorium-and-spa treatment with balneotherapy procedures. Using the example of equinoxes under experimental conditions on laboratory rats, it has been shown that balneological procedures will more effectively perform rehabilitative functions when the light phase of the day expands as a result of such a shift, but not the dark one.

Pharmacokinetics-Based Chronoefficacy of Semen Strychni and Tripterygium Glycoside Tablet Against Rheumatoid Arthritis

Rheumatoid arthritis is a systemic autoimmune disease characterized by synovial inflammation and bone destruction. Identifying drugs with time-varying efficacy and toxicity, and elucidating the mechanisms would help to improve treatment efficacy and reduce adverse effects. Here, we aimed to determine the chronoefficacy of semen strychni (SS) and tripterygium glycoside tablet (TGT) against rheumatoid arthritis in mice, and to investigate a potential role of circadian pharmacokinetics in generating chronoefficacy. SS extract and TGT suspension were prepared with ultrasonication. Effects of SS and TGT on collagen-induced arthritis (CIA) were evaluated by measuring TNF-α and IL-6 levels. SS dosed at ZT18 was more effective in protecting against CIA than drug dosed at ZT6 (i.e., lower levels of key inflammatory factors at ZT18 than at ZT6). This was accompanied by higher systemic exposure levels of strychnine and brucine (two main putative active ingredients of SS) in ZT18-treated than in ZT6-treated CIA mice. TGT dosing at ZT2 showed a better efficacy against CIA as compared to herb doing at ZT14. Consistently, ZT2 dosing generated a higher exposure of triptolide (a main putative active ingredient of TGT) as compared to ZT14 dosing in CIA mice. Moreover, strychnine, brucine, and triptolide significantly inhibited the proliferation of fibroblast-like synoviocytes, and reduced the production of TNF-α and IL-6 and the mRNAs of TNF-α, IL-6, COX-2, and iNOS, suggesting that they possessed an anti-arthritis activity. In conclusion, SS and TGT display chronoefficacy against rheumatoid arthritis in mice, that is attributed to circadian pharmacokinetics of main active ingredients. Our findings have implications for improving treatment outcomes of SS and TGT via timed delivery.

Pharmacokinetics-based chronoefficacy of Fuzi against chronic kidney disease

OBJECTIVES

Identifying drugs with time-varying efficacy or toxicity, and understanding the underlying mechanisms would help to improve treatment efficacy and reduce adverse effects. In this study, we uncovered that the therapeutic effect of Fuzi (the lateral root of Aconitum carmichaelii Debeaux) depended on the dosing time in mice with adenine-induced chronic kidney disease (CKD).

METHODS

The Fuzi efficacy was determined by biomarker measurements [i.e. plasma creatinine (CRE), blood urea nitrogen (BUN) and urinary N-acetyl-β-D-glucosaminidase (NAG)], as well as inflammation, fibrosis and histological analyses. Circadian regulation of Fuzi pharmacokinetics and efficacy was evaluated using brain and muscle Arnt-like protein-1 (Bmal1)-deficient (Bmal1-/-) mice.

KEY FINDINGS

The Fuzi efficacy was higher when the drug was dosed at ZT10 and was lower when the drug was dosed at other times (ZT2, ZT6, ZT14, ZT18 and ZT22) according to measurements of plasma CRE, BUN and urinary NAG. Consistently, ZT10 (5 PM) dosing showed a stronger protective effect on the kidney (i.e. less extensive tubular injury) as compared to ZT22 (5 AM) dosing. This was supported by lower levels of inflammatory and fibrotic factors (IL-1β, IL-6, Tnf-α, Ccl2, Tgfb1 and Col1a1) at ZT10 than at ZT22. Pharmacokinetic analyses showed that the area under the curve (AUC) values (reflective of systemic exposure) and renal distribution of aconitine, hypaconitine and mesaconitine (three putative active constituents) for Fuzi dosing at ZT10 were significantly higher than those for herb dosing at ZT22, suggesting a role of circadian pharmacokinetics in Fuzi chronoefficacy. Drug efficacy studies confirmed that aconitine, hypaconitine and mesaconitine possessed a kidney-protecting effect. In addition, genetic knockout of Bmal1 in mice abolished the time-dependency of Fuzi pharmacokinetics and efficacy. This reinforced the existence of chronoefficacy for Fuzi and supported the role of circadian pharmacokinetics in Fuzi chronoefficacy.

CONCLUSIONS

The efficacy of Fuzi against CKD depends on the dosing time in mice, which is associated with circadian pharmacokinetics of the three main active constituents (i.e. aconitine, hypaconitine and mesaconitine). These findings highlight the relevance of dosing time in the therapeutic outcomes of herbal medicines.

Water-soluble alkaloids extracted from Aconiti Radix lateralis praeparata protect against chronic heart failure in rats via a calcium signaling pathway

ETHNOPHARMACOLOGICAL RELEVANCE

Many studies have shown the beneficial effects of aconite water-soluble alkaloid extract (AWA) in experimental models of heart disease, which have been ascribed to the presence of aconine, hypaconine, talatisamine, fuziline, neoline, and songorine. This study evaluated the effects of a chemically characterized AWA by chemical content, evaluated its effects in suprarenal abdominal aortic coarctation surgery (AAC)-induced chronic heart failure (CHF) in rats, and revealed the underlying mechanisms of action by proteomics.

METHODS

Rats were distributed into different groups: sham, model, and AWA-treated groups (10, 20, and 40 mg/kg/day). Sham rats received surgery without AAC, whereas model rats an AWA-treated groups underwent AAC surgery. after 8 weeks, the treatment group was fed AWA for 4 weeks, and body weight was assessed weekly. At the end of the treatment, heart function was tested by echocardiography. AAC-induced chronic heart failure, including myocardial fibrosis, cardiomyocyte hypertrophy, and apoptosis, was evaluated in heart tissue and plasma by RT-qPCR, ELISA, hematoxylin and eosin (H&E) staining, Masson's trichrome staining, TUNEL staining, and immunofluorescence staining of α-SMA, Col Ⅰ, and Col Ⅲ. Then, a proteomics approach was used to explore the underlying mechanisms of action of AWA in chronic heart failure.

RESULTS

AWA administration reduced body weight gain, myocardial fibrosis, cardiomyocyte hypertrophy, and apoptosis, and rats showed improvement in cardiac function compared to model group. The extract significantly ameliorated the AAC-induced altered expression of heart failure markers such as ANP, NT-proBNP, and β-MHC, as well as fibrosis, hypertrophy markers MMP-2 and MMP-9, and other heart failure-related factors including plasma levels of TNF-α and IL-6. Furthermore, the extract reduced the protein expression of α-SMA, Col Ⅰ, and Col Ⅲ in the left ventricular (LV), thus inhibiting the LV remodeling associated with CHF. In addition, proteomics characterization of differentially expressed proteins showed that AWA administration inhibited left ventricular remodeling in CHF rats via a calcium signaling pathway, and reversed the expression of RyR2 and SERCA2a.

CONCLUSIONS

AWA extract exerts beneficial effects in an AAC-induced CHF model in rats, which was associated with an improvement in LV function, hypertrophy, fibrosis, and apoptotic status. These effects may be related to the regulation of calcium signaling by the altered expression of RyR2 and SERCA2a.

Systematically explore the potential hepatotoxic material basis and molecular mechanism of Radix Aconiti Lateralis based on the concept of toxicological evidence chain (TEC)

Radix aconiti lateralis (Fuzi) is widely used in China as a traditional Chinese medicine for the treatment of asthenia, pain and inflammation. However, its toxic alkaloids often lead to adverse reactions. Currently, most of the toxicity studies on Fuzi are focused on the heart and nervous system, and more comprehensive toxicity studies are needed. In this study, based on the previous reports of Fuzi hepatotoxicity, serum pharmacochemistry and network toxicology were used to screen the potential toxic components of Heishunpian(HSP), a processed product of Fuzi, and to explore the possible mechanism of HSP-induced hepatotoxicity. The results obtained are expressed based on the toxicological evidence chain (TEC). It was found that 22 potential toxic components screened can affect Th17 cell differentiation, Jak-STAT signaling pathway, glutathione metabolism, and other related pathways by regulating AKT1, IL2, F2, GSR, EGFR and other related targets, which induces oxidative stress, metabolic disorders, cell apoptosis, immune response, and excessive release of inflammatory factors, eventually inducing liver damage in rats. This is the first study on HSP-induced hepatotoxicity based on the TEC concept, providing references for further studies on the toxicity mechanism of Fuzi.

Light-resetting impact on behavior and the central circadian clock in two vole species (genus: Lasiopodomys)

The behavioral circadian rhythms of subterranean rodents show intra- and interspecies diversity in terms of adaptation to dark underground environments, but the endogenous molecular mechanism of rhythm regulation in the suprachiasmatic nuclei (SCN) is stable to many species. In this study, we sought to determine the rhythms of behavior and central molecular regulatory mechanisms in the SCN of the subterranean Mandarin voles (Lasiopodomys mandarinus) compared with a related aboveground species, Brandt's voles (Lasiopodomys brandtii). Both species were reared under a 12 L:12 D cycle or in continuous darkness for 4 weeks. The pattern of wheel-running activity was similar in both species and had a periodicity of almost 24 h regardless of rearing conditions. However, the intensity of daily activity in Brandt's voles decreased markedly in darkness, while there was no significant difference in activity intensity in mandarin voles under different light regimes. In both vole species, all tested genes in the SCN showed significant time-dependent expression regardless of rearing conditions, and the expression levels of most genes did not differ significantly between different species and conditions. However, the peak phase shift in gene expression differed between the two species. In conclusion, behavioral patterns in mandarin and Brandt's voles were regulated by a stable molecular endogenous biological clock. The observed differences in activity intensity and phase shift suggest that different mechanisms regulate circadian rhythms in different living environments.

Circadian Clock-Controlled Drug Metabolism: Implications for Chronotherapeutics

Dependence of drug metabolism on dosing time has long been recognized. However, only recently are the underlying mechanisms for circadian drug metabolism being clarified. Diurnal rhythmicity in expression of drug-metabolizing enzymes is believed to be a key factor determining circadian metabolism. Supporting the notion that biological rhythms are generated and maintained by the circadian clock, a number of diurnal enzymes are under the control of the circadian clock. In general, circadian clock genes generate and regulate diurnal rhythmicity in drug-metabolizing enzymes via transcriptional actions on one or two of three cis-elements (i.e., E-box, D-box, and Rev-erb response element or RAR-related orphan receptor response element). Additionally, cycling or clock-controlled nuclear receptors such as hepatocyte nuclear factor 4α and peroxisome proliferator-activated receptor γ are contributors to diurnal enzyme expression. These newly discovered mechanisms for each of the rhythmic enzymes are reviewed in this article. We also discuss how the rhythms of enzymes are translated to circadian pharmacokinetics and drug chronotoxicity, which has direct implications for chronotherapeutics. Our discussion is also extended to two diurnal transporters (P-glycoprotein and multidrug resistance-associated protein 2) that have an important role in drug absorption. Although the experimental evidence is lacking in metabolism-based chronoefficacy, circadian genes (e.g., Rev-erbα) as drug targets are shown to account for diurnal variability in drug efficacy. SIGNIFICANCE STATEMENT: Significant progress has been made in understanding the molecular mechanisms for generation of diurnal rhythmicity in drug-metabolizing enzymes. In this article, we review the newly discovered mechanisms for each of the rhythmic enzymes and discuss how the rhythms of enzymes are translated to circadian pharmacokinetics and drug chronotoxicity, which has direct implications for chronotherapeutics.