Sodium aescinate and its bioactive components induce degranulation via oxidative stress in RBL-2H3 mast cells

Sodium aescinate induces hepatotoxicity through apoptosis and ferroptosis by inhibiting the Nrf2/CTH pathway

ETHNOPHARMACOLOGICAL RELEVANCE

The seed of Aesculus wilsonii Rehd., also known as Suoluozi in China, is a traditional Chinese herb included in the Pharmacopoeia of China (2020). Sodium aescinate (SA) is derived from the Aesculus wilsonii Rehd.'s seeds and is extensively used in clinical practice.

AIM OF THE STUDY

The study investigated the involvement of the Nrf2/CTH pathway in SA-induced hepatotoxicity and explored potential strategies for alleviating SA-induced liver damage.

MATERIALS AND METHODS

The ICR mice and AML12 mouse hepatocytes were exposed to SA. The levels of Fe2+, cysteine (Cys), glutathione (GSH), hydrogen sulfide (H2S), ROS, lipid peroxides and caspase-3 activity were assessed. The effects of SA on signaling pathways related to ferroptosis and apoptosis were examined. Furthermore, genetic modification or agonists of Nrf2 and CTH were co-treated with SA.

RESULTS

SA triggered ferroptosis and apoptosis in AML12 cells and mouse livers, characterized by a decline in Cys, GSH, and H2S levels, as well as accumulation of Fe2+, ROS and lipid peroxides, mitochondrial dysfunction, and chromatin condensation. SA decreased Nrf2, CTH, and Bcl-2 levels, elevated Bax levels, and activated caspase-9/3. Overexpression of Nrf2 or CTH, or NAC supplementation alleviated SA-induced ferroptosis by upregulating Cys and GSH levels. Overexpression of Nrf2 or CTH, or NaHS supplementation increased H2S levels, which reduced the interaction between p616-Drp1 and VDAC1 by enhancing Drp1 S-sulfenylation, thereby alleviating SA-induced mitochondrial-dependent apoptosis. Furthermore, DMF or Met mitigated SA-induced hepatotoxicity by activating the Nrf2/CTH pathway.

CONCLUSIONS

SA triggers oxidative stress, mitochondrial dysfunction, apoptosis, and ferroptosis, ultimately leading to liver damage by suppressing the Nrf2/CTH pathway.

Sodium aescinate-induced hepatotoxicity via ATF4/GSH/GPX4 axis-mediated ferroptosis

Sodium aescinate (SA), a natural plant extract with various bioactivities, is widely used to treat oedema and inflammation in clinics. However, adverse events, including liver injury, kidney injury, and phlebitis, have been reported in patients with SA in recent years. In this study, we used BALB/c mice and L02 cells to evaluate the role of ferroptosis in SA-induced liver injury. SA significantly increased AST, ALT, MDA and Fe2+, decreased GSH levels, and induced pathological changes in the liver in vivo. SA also reduced the viability of L02 cells and induced LDH release, intracellular cysteine reduction, GSH depletion, iron accumulation, ROS production, and lipid peroxidation, indicating that SA causes ferroptosis. In addition, SA inhibited transcriptional activity of activating transcription factor 4 (ATF4) and subsequently reduced the expression of the downstream genes xCT (solute carrier family 7a member 11, SLC7A11) and Cystathionine gamma-lyase (CTH) which play vital roles in GSH biosynthesis. Interestingly, the cytotoxic effects of SA were effectively attenuated by ATF4 overexpression, while they were significantly aggravated by ATF4 silencing. These results revealed that SA triggers hepatocyte ferroptosis by inhibiting the activity of ATF4, which causes an oxidative imbalance.

Nrf2/FSP1/CoQ10 axis-mediated ferroptosis is involved in sodium aescinate-induced nephrotoxicity

Sodium aescinate (SA), an active compound found in horse chestnut seeds, is widely used in clinical practice. Recently, the incidence of SA-induced adverse events, particularly renal impairment, has increased. Our previous work demonstrated that SA causes severe nephrotoxicity via nephrocyte ferroptosis; however, the underlying mechanism remains to be fully elucidated. In the current study, we investigated additional molecular pathways involved in SA-induced nephrotoxicity. Our results showed that SA inhibited cell viability, disrupted cellular membrane integrity, and enhanced reactive oxygen species (ROS), ferrous iron (Fe2+), and malondialdehyde (MDA) levels, as well as lipid peroxidation in rat proximal renal tubular epithelial cell line (NRK-52E) cells. SA also depleted coenzyme Q10 (CoQ10, ubiquinone) and nicotinamide adenine dinucleotide (NADH) and reduced ferroptosis suppressor protein 1 (FSP1) and polyprenyltransferase (coenzyme Q2, COQ2) activity, triggering lipid peroxidation and ROS accumulation in mouse kidneys and NRK-52E cells. The overexpression of COQ2, FSP1, or CoQ10 (ubiquinone) supplementation effectively attenuated SA-induced ferroptosis, whereas iFSP1 or 4-formylbenzoic acid (4-CBA) pretreatment exacerbated SA-induced nephrotoxicity. Additionally, SA decreased nuclear factor-erythroid-2-related factor 2 (Nrf2) levels and inhibited Nrf2 binding to the -1170/-1180 bp ARE site in FSP1 promoter, resulting in FSP1 suppression. Overexpression of Nrf2 or its agonist dimethyl fumarate (DMF) promoted FSP1 expression, thereby improving cellular antioxidant capacity and alleviating SA-induced ferroptosis. These results suggest that SA-triggers renal injury through oxidative stress and ferroptosis, driven by the suppression of the Nrf2/FSP1/CoQ10 axis.

Comparative analyses of various IgE-mediated and non-IgE-mediated inducers of mast cell degranulation for in vitro study

In vitro investigations of mast cell (MC) degranulation are essential for studying many diseases, particularly allergy and urticaria. Many MC-degranulation inducers are currently available. However, there is no previous systematic comparative analysis of these available inducers in term of their efficacies to induce MC degranulation. Herein, we performed systematic comparisons of efficacies of five well-known and commonly used MC-degranulation inducers. RBL-2H3 cells were sensitized with 50 ng/ml anti-DNP IgE or biotinylated IgE followed by stimulation with 100 ng/ml DNP-BSA or streptavidin, respectively. For non-IgE-mediated inducers, the cells were treated with 5 µg/ml substance P, compound 48/80, or A23187. At 15-, 30-, 45- and 60-min post-induction, several common MC-degranulation markers (including intracellular [Ca2+], β-hexosaminidase release, tryptase expression by immunofluorescence staining, cellular tryptase level by immunoblotting, secretory tryptase level by immunoblotting, CD63 expression by immunofluorescence staining, and CD63 expression by flow cytometry) were evaluated. The data showed that all these markers significantly increased after activation by all inducers. Among them, A23187 provided the greatest degrees of increases in intracellular [Ca2+] and β-hexosaminidase release at all time-points and upregulation of CD63 at one time-point. These data indicate that all these IgE-mediated (anti-DNP IgE/DNP-BSA and biotinylated IgE/streptavidin) and non-IgE-mediated (substance P, compound 48/80, and A23187) inducers effectively induce MC degranulation, while A23187 seems to be the most effective inducer for MC degranulation.

Sodium aescinate induces renal toxicity by promoting Nrf2/GPX4-mediated ferroptosis

Sodium aescinate (SA) is extracted from Aesculus wilsonii Rehd seeds and was first marketed as a medicament in German. With the wide application of SA in clinical practice, reports of adverse drug reactions and adverse events have gradually increased, including renal impairment. However, the pathogenic mechanisms of SA have not yet been fully elucidated. The toxic effects and underlying mechanisms of SA were explored in this study. Our data showed that SA significantly elevated the levels of blood urea nitrogen (BUN), serum creatinine (Scr) and Kidney injury molecule 1 (Kim-1), accompanied by pathologically significant changes in renal tissue. SA induced NRK-52E cell death and disrupted the integrity of the cell membrane. Moreover, SA caused significant reductions in FTH, Nrf2, xCT, GPX4, and FSP1 levels, but increased TFR1 and ACSL4 levels. SA decreased glutathione peroxidase (GPx), glutathione (GSH) and cysteine (Cys) levels, but improved Fe2+, malondialdehyde (MDA), reactive oxygen species (ROS) and lipid peroxidation levels, ultimately leading to the induction of ferroptosis. Importantly, inhibition of ferroptosis or activation of the Nrf2/GPX4 pathway prevented SA-induced nephrotoxicity. These findings indicated that SA induced oxidative damage and ferroptosis-mediated kidney injury by suppressing the Nrf2/GPX4 axis activity.

Sodium aescinate improve behavioral performance by inhibiting dorsal raphe nucleus NLRP3 inflammasome in Post-traumatic stress disorder Rat Model

Growing evidence suggest that NLRP3 inflammasome activation in hippocampus and amygdala is involved in the pathophysiology of PTSD. Our previous studies have demonstrated that apoptosis of dorsal raphe nucleus (DRN) contributes to the pathological progression of PTSD. Recent studies by others have shown that in brain injury sodium aescinate (SA) has a protective effect on neurons by inhibiting inflammatory response pathways, thereby relieving symptoms. Here, we extend the therapeutic effects of SA to PTSD rats. We found that PTSD was associated with significant activation of the NLRP3 inflammasome in DRN, whereas administration of SA significantly inhibited DRN NLRP3 inflammasome activation and reduced DRN apoptosis level. SA also improved learning and memory ability and reduced anxiety and depression level in PTSD rats. In addition, NLRP3 inflammasome activation in DRN of PTSD rats impaired mitochondria function by inhibiting ATP synthesis and increasing ROS production, whereas SA can effectively reverse the pathological progression of mitochondria. We recommend SA as a new candidate for the pharmacological treatment of PTSD.

Systematic comparisons of various markers for mast cell activation in RBL-2H3 cells

Mast cell activation plays a key role in various allergic diseases and anaphylaxis. Several methods/techniques can be used for detection of mast cell activation. However, there was no previous systematic evaluation to compare the efficacy of each method/technique. The present study thus systematically compared various markers for mast cell activation induced by IgE cross-linking. The widely used RBL-2H3 mast cells were sensitized with anti-DNP (dinitrophenyl) IgE overnight and activated with DNP-BSA (bovine serum albumin) for up to 4 h. The untreated cells and those with anti-DNP IgE sensitization but without DNP-BSA activation served as the controls. Intracellular calcium level gradually increased to ~2-fold at 1 h, reached its peak (~5-fold) at 2 h, and returned to the basal level at 3-h post-activation. The increases in cellular tryptase level (by Western blotting) (~0.3- to 0.4-fold) and average cell size (~2.5-fold) and decrease of nucleus/cytoplasm ratio (~0.4- to 0.5-fold) were marginal at all time-points. By contrast, β-hexosaminidase release and CD63 expression (by both flow cytometry and immunofluorescence detection/localization), secreted tryptase level (by Western blotting), and tryptase expression (by immunofluorescence detection/localization) stably and obviously increased (~10-fold as compared with the untreated control and sensitized-only cells or detectable only after activation). Based on these data, the stably obvious increases (by ≥ 10-fold) in β-hexosaminidase release, CD63 expression (by both flow cytometry and immunofluorescence staining), secreted tryptase level (by Western blotting), and tryptase expression (by immunofluorescence staining) are recommended as the markers of choice for the in vitro study of mast cell activation using RBL-2H3 cells.

Targeting Nrf2-Mediated Oxidative Stress Response in Traumatic Brain Injury: Therapeutic Perspectives of Phytochemicals

Traumatic brain injury (TBI), known as mechanical damage to the brain, impairs the normal function of the brain seriously. Its clinical symptoms manifest as behavioral impairment, cognitive decline, communication difficulties, etc. The pathophysiological mechanisms of TBI are complex and involve inflammatory response, oxidative stress, mitochondrial dysfunction, blood-brain barrier (BBB) disruption, and so on. Among them, oxidative stress, one of the important mechanisms, occurs at the beginning and accompanies the whole process of TBI. Most importantly, excessive oxidative stress causes BBB disruption and brings injury to lipids, proteins, and DNA, leading to the generation of lipid peroxidation, damage of nuclear and mitochondrial DNA, neuronal apoptosis, and neuroinflammatory response. Transcription factor NF-E2 related factor 2 (Nrf2), a basic leucine zipper protein, plays an important role in the regulation of antioxidant proteins, such as oxygenase-1(HO-1), NAD(P)H Quinone Dehydrogenase 1 (NQO1), and glutathione peroxidase (GPx), to protect against oxidative stress, neuroinflammation, and neuronal apoptosis. Recently, emerging evidence indicated the knockout (KO) of Nrf2 aggravates the pathology of TBI, while the treatment of Nrf2 activators inhibits neuronal apoptosis and neuroinflammatory responses via reducing oxidative damage. Phytochemicals from fruits, vegetables, grains, and other medical herbs have been demonstrated to activate the Nrf2 signaling pathway and exert neuroprotective effects in TBI. In this review, we emphasized the contributive role of oxidative stress in the pathology of TBI and the protective mechanism of the Nrf2-mediated oxidative stress response for the treatment of TBI. In addition, we summarized the research advances of phytochemicals, including polyphenols, terpenoids, natural pigments, and otherwise, in the activation of Nrf2 signaling and their potential therapies for TBI. Although there is still limited clinical application evidence for these natural Nrf2 activators, we believe that the combinational use of phytochemicals such as Nrf2 activators with gene and stem cell therapy will be a promising therapeutic strategy for TBI in the future.

Anshen Buxin Liuwei Pill, a Mongolian Medicinal Formula, Could Protect H2O2-Induced H9c2 Myocardial Cell Injury by Suppressing Apoptosis, Calcium Channel Activation, and Oxidative Stress

Background

Anshen Buxin Liuwei pill (ABLP) is a Mongolian medicinal formula which has a therapeutic effect on the symptoms such as coronary heart disease, angina pectoris, arrhythmia, depression and irritability, palpitation, and short breath. However, its bioactivity against cardiac injury remains unclear.

Methods

The protective effect of ABLP was evaluated using H9c2 cells. Cell viability, intracellular Ca²⁺, reactive oxidative indices, and mitochondrial membrane potential (∆ψ) were assessed, respectively. The mRNA levels of Ca²⁺ channel-related genes (DHPR, RyR2, and SCN5A) and oxidative stress-related genes (Keap1, Nrf2, and HO-1) were measured by RT-PCR.

Results

0.5–50 μg/mL ABLP could significantly decrease H₂O₂-induced cell injury by suppressing cell necrosis/apoptosis and excess oxidative stress, ameliorating the collapse of ∆ψ, and reducing intracellular Ca²⁺ concentration. Furthermore, 0.5–50 μg/mL ABLP reversed H₂O₂-induced imbalance in the mRNA levels of DHPR, RyR2, SCN5A, Keap1, Nrf2, and HO-1 gene in H9c2 cells, which further illustrate the mechanism.

Conclusion

ABLP provided protective and therapeutic benefits against H₂O₂-induced H9c2 cell injury, indicating that this formula can effectively treat coronary disease. In addition, the present study also provides an in-depth understanding of the pharmacological functions of ABLP, which may lead to further successful applications of Mongolian medicine.