Pinocembrin alleviates lipopolysaccharide-induced myocardial injury and cardiac dysfunction in rats by inhibiting p38/JNK MAPK pathway

Bridging the gap between GLP1-receptor agonists and cardiovascular outcomes: evidence for the role of tirzepatide

Tirzepatide is a new drug targeting glucagon-like peptide 1(GLP1) and gastric inhibitory polypeptide (GIP) receptors. This drug has demonstrated great potential in improving the clinical outcomes of patients with type 2 diabetes. It can lead to weight loss, better glycemic control, and reduced cardiometabolic risk factors. GLP1 receptor agonists have been proven effective antidiabetic medications with possible cardiovascular benefits. Even though they have been proven to reduce the risk of major adverse cardiovascular events, their effectiveness in treating heart failure is unknown. Unlike traditional GLP1 receptor agonists, tirzepatide is more selective for the GIP receptor, resulting in a more balanced activation of these receptors. This review article discusses the possible mechanisms tirzepatide may use to improve cardiovascular health. That includes the anti-inflammatory effect, the ability to reduce cell death and promote autophagy, and also its indirect effects through blood pressure, obesity, and glucose/lipid metabolism. Additionally, tirzepatide may benefit atherosclerosis and lower the risk of major adverse cardiac events. Currently, clinical trials are underway to evaluate the safety and efficacy of tirzepatide in patients with heart failure. Overall, tirzepatide's dual agonism of GLP1 and GIP receptors appears to provide encouraging cardiovascular benefits beyond glycemic control, offering a potential new therapeutic option for treating cardiovascular diseases and heart failure.

CNS-Active p38α MAPK Inhibitors for the Management of Neuroinflammatory Diseases: Medicinal Chemical Properties and Therapeutic Capabilities

During the last two decades, many p38α mitogen-activated protein kinase (p38α MAPK) inhibitors have been developed and tested in preclinical/clinical studies for the treatment of various disorders, especially problems with the origin of inflammation. Previous studies strongly suggest the involvement of the p38α MAPK pathway in the pathogenesis of neurodegenerative disorders. Despite the significant progress made in this field, so far no studies have focused on p38α MAPK inhibitors that have the capability to be used for the treatment of neurodegenerative disorders. In the present review, we evaluated a wide range of well-known p38α MAPK inhibitors (more than 140 small molecules) by measuring key physicochemical parameters to identify those capable of successfully crossing the blood-brain barrier (BBB). As a result, we identify about 50 naturally occurring and synthetic p38α MAPK inhibitors with high potential to cross the BBB, which can be further explored in the future for the treatment of neurodegenerative disorders. In addition, a detailed analysis of the previously released X-ray crystal structure of the inhibitors in the active site of the p38α MAPK enzyme revealed that some residues such as Met109 play a critical role in the occurrence of effective interactions by constructing strong H-bonds. This study can encourage scientists to focus more on the design, production, and biological evaluation of new central nervous system (CNS)-active p38α MAPK inhibitors in the future.

Crosstalk among Reactive Oxygen Species, Autophagy and Metabolism in Myocardial Ischemia and Reperfusion Stages

Myocardial ischemia is the most common cardiovascular disease. Reperfusion, an important myocardial ischemia tool, causes unexpected and irreversible damage to cardiomyocytes, resulting in myocardial ischemia/reperfusion (MI/R) injury. Upon stress, especially oxidative stress induced by reactive oxygen species (ROS), autophagy, which degrades the intracellular energy storage to produce metabolites that are recycled into metabolic pathways to buffer metabolic stress, is initiated during myocardial ischemia and MI/R injury. Excellent cardioprotective effects of autophagy regulators against MI and MI/R have been reported. Reversing disordered cardiac metabolism induced by ROS also exhibits cardioprotective action in patients with myocardial ischemia. Herein, we review current knowledge on the crosstalk between ROS, cardiac autophagy, and metabolism in myocardial ischemia and MI/R. Finally, we discuss the possible regulators of autophagy and metabolism that can be exploited to harness the therapeutic potential of cardiac metabolism and autophagy in the diagnosis and treatment of myocardial ischemia and MI/R.

High-dose Vitamin C injection ameliorates against sepsis-induced myocardial injury by anti-apoptosis, anti-inflammatory and pro-autophagy through regulating MAPK, NF-κB and PI3K/AKT/mTOR signaling pathways in rats

AIMS

This study aimed to evaluate the effects of VC on SIMI in rats.

METHODS

In this study, the survival rate of high dose VC for SIMI was evaluated within 7 days. Rats were randomly assigned to three groups: Sham group, CLP group, and high dose VC (500 mg/kg i.v.) group. The animals in each group were treated with drugs for 1 day, 3 days or 5 days, respectively. Echocardiography, myocardial enzymes and HE were used to detect cardiac function. IL-1β, IL-6, IL-10 and TNF-α) in serum were measured using ELISA kits. Western blot was used to detect proteins related to apoptosis, inflammation, autophagy, MAPK, NF-κB and PI3K/Akt/mTOR signaling pathways.

RESULTS

High dose VC improved the survival rate of SIMI within 7 days. Echocardiography, HE staining and myocardial enzymes showed that high-dose VC relieved SIMI in rats in a time-dependent manner. And compared with CLP group, high-dose VC decreased the expressions of pro-apoptotic proteins, while increased the expression of anti-apoptotic protein. And compared with CLP group, high dose VC decreased phosphorylation levels of Erk1/2, P38, JNK, NF-κB and IKK α/β in SIMI rats. High dose VC increased the expression of the protein Beclin-1 and LC3-II/LC3-I ratio, whereas decreased the expression of P62 in SIMI rats. Finally, high dose VC attenuated phosphorylation of PI3K, AKT and mTOR compared with the CLP group.

SIGNIFICANCE

Our results showed that high dose VC has a good protective effect on SIMI after continuous treatment, which may be mediated by inhibiting apoptosis and inflammatory, and promoting autophagy through regulating MAPK, NF-κB and PI3K/AKT/mTOR pathway.

Dapagliflozin ameliorates sepsis-induced heart injury by inhibiting cardiomyocyte apoptosis and electrical remodeling through the PI3K/Akt pathway

BACKGROUND

Sepsis-induced heart injury is one of the leading causes of circulation disorders worldwide. Dapagliflozin, a sodium-glucose cotransporter 2 inhibitor mainly used for controlling blood glucose, has been shown to exert a protective effect on cardiomyocytes. However, the protective effect of dapagliflozin against sepsis-induced cardiac injury and the underlying mechanism needs to be studied.

AIM

This study aims to investigate the effect of dapagliflozin on sepsis-induced cardiomyopathy and the potential mechanisms involved.

METHODS

The rat model of sepsis was constructed by intraperitoneal injection of lipopolysaccharide. Echocardiography and electrophysiological studies were performed to detect changes in cardiac function and electrical activity. Cardiac pathological alternation and cardiomyocyte apoptosis were measured by H&E staining, serological analysis, immunohistochemical, immunofluorescence, and TUNEL assays. Western blot and qRT-PCR were performed to elucidate the underlying mechanism of dapagliflozin. Additionally, corresponding experiments in H9c2 cells were performed to further validate the mechanisms in vitro.

RESULTS

Dapagliflozin improved cardiac dysfunction and reduced the susceptibility to ventricular arrhythmias in sepsis rats by ameliorating cardiac inflammation, suppressing cardiomyocyte apoptosis, and alleviating ventricular electrical remodeling. The PI3K/Akt signaling pathway inhibitor inhibited the anti-apoptotic effect of dapagliflozin, indicating that the protective effect was related to the activation of the PI3K/Akt pathway.

CONCLUSION

Dapagliflozin ameliorated sepsis-induced cardiac injury by suppressing electrical remodeling and cardiomyocyte apoptosis, which could be attributed to the PI3K/Akt pathway.

Therapeutic prospects of naturally occurring p38 MAPK inhibitors tanshinone IIA and pinocembrin for the treatment of SARS-CoV-2-induced CNS complications

P38 mitogen-activated protein kinase (p38 MAPK) signaling pathway is closely related to severe acute respiratory syndrome coronavirus-2 (SARS-CoV-2) replication and hyperinflammatory responses in coronavirus disease 2019 (COVID-19). Therefore, blood-brain barrier-penetrating p38 MAPK inhibitors have good potential for the treatment of central nervous system (CNS) complications of COVID-19. The aim of the present study is the characterization of the therapeutic potential of tanshinone IIA and pinocembrin for the treatment of CNS complications of COVID-19. Studies published in high-quality journals indexed in databases Scopus, Web of Science, PubMed, and so forth were used to review the therapeutic capabilities of selected compounds. In continuation of our previous efforts to identify agents with favorable activity/toxicity profiles for the treatment of COVID-19, tanshinone IIA and pinocembrin were identified with a high ability to penetrate the CNS. Considering the nature of the study, no specific time frame was determined for the selection of studies, but the focus was strongly on studies published after the emergence of COVID-19. By describing the association of COVID-19-induced CNS disorders with p38 MAPK pathway disruption, this study concludes that tanshinone IIA and pinocembrin have great potential for better treatment of these complications. The inclusion of these compounds in the drug regimen of COVID-19 patients requires confirmation of their effectiveness through the conduction of high-quality clinical trials.

Tirzepatide attenuates lipopolysaccharide-induced left ventricular remodeling and dysfunction by inhibiting the TLR4/NF-kB/NLRP3 pathway

BACKGROUNDS

Sepsis-induced cardiac dysfunction is a leading cause of mortality in intensive care units. Tirzepatide, a dual glucagon-like peptide-1 (GLP-1) and glucose-dependent insulinotropic polypeptide (GIP) receptor agonist, possess cardio-protective, their effects on sepsis-induced cardiomyopathy remain unknown.

METHODS

C57BL/6 mice received subcutaneous injections of tirzepatide once a day for 14 days before subjected to LPS challenge for 12 h. LPS-induced cardiac dysfunction and its potential mechanisms were estimated by pathological analysis, echocardiographic measurement, electrocardiography, langendorff-perfused heart and molecular analysis.

RESULTS

Pretreatment with tirzepatide attenuates LPS-induced cardiac dysfunction. tirzepatide remarkably reduces LPS-mediated inflammatory responses by inhibiting  the cardiac protein levels of TNF-α, IL-6, and IL-1B in mice. Interestingly, tirzepatide administration also improves cardiomyocytes apoptosis caused by LPS treatment. Furthermore, the protective roles of irzepatide against LPS-mediated increased inflammatory responses and decreased cardiomyocytes apoptosis are partially blunted by inhibiting TLR4/NF-kB/NLRP3 inflammation signaling. In addition, tirzepatide reduce the susceptibility ventricular arrhythmia in LPS-treated mice.

CONCLUSION

In brief, tirzepatide attenuates LPS-induced left ventricular remodeling and dysfunction by inhibiting the TLR4/NF-kB/NLRP3 pathway.

Polygonum orientale L. Alleviates Myocardial Ischemia-Induced Injury via Activation of MAPK/ERK Signaling Pathway

Although Polygonum orientale L. (PO) has a beneficial effect on treatment of myocardial ischemia (MI), its mechanism remains unclear. This study aimed to explore the pharmacological mechanism of PO against MI through MAPK signaling pathways. Firstly, the therapeutic effect of PO was evaluated for treatment of MI mice. Using Western blot and immunohistochemistry, the influence of PO on MAPK signaling pathways and cell apoptosis was investigated. Subsequently, one key pathway (ERK) of MAPK signaling pathways was screened out, on which PO posed the most obvious impact. Finally, an inhibitor of ERK1/2 was utilized to further verify the regulatory effect of PO on the MAPK/ERK signaling pathway. It was found that PO could reduce the elevation of the ST segment; injury of heart tissue; the activity of LDH, CK, NOS, cNOS and iNOS and the levels of NO, BNP, TNF-α and IL-6. It is notable that PO could significantly modulate the protein content of p-ERK/ERK in mice suffering from MI but hardly had an effect on p-JNK/JNK and p-p38/p38. Additionally, the expressions of bax, caspase3 and caspase9 were inhibited in heart tissue in the PO-treated group. To evaluate whether ERK1/2 inhibitor (PD98059) could block the effect of PO on treatment of MI, both PO and PD98059 were given to mice with MI. It was discovered that the inhibitor indeed could significantly reverse the regulatory effects of PO on the above indicators, indicating that PO could regulate p-ERK/ERK. This study provides experimental evidence that PO extenuates MI injury, cardiomyocyte apoptosis and inflammation by activating the MAPK/ERK signaling pathway.

Current advances on the therapeutic potential of pinocembrin: An updated review

Pinocembrin (5,7-dihydroxyflavone) is a major flavonoid found in many plants, fungi and hive products, mainly honey and propolis. Several in vitro and preclinical studies revealed numerous pharmacological activities of pinocembrin including antioxidant, anti-inflammatory, antimicrobial, neuroprotective, cardioprotective and anticancer activities. Here, we comprehensively review and critically analyze the studies carried out on pinocembrin. We also discuss its potential mechanisms of action, bioavailability, toxicity, and clinical investigations. The wide therapeutic window of pinocembrin makes it a promising drug candidate for many clinical applications. We recommend some future perspectives to improve its pharmacokinetic and pharmacodynamic properties for better delivery that may also lead to new therapeutic advances.

Aldehyde Dehydrogenase 2 Ameliorates LPS-Induced Acute Kidney Injury through Detoxification of 4-HNE and Suppression of the MAPK Pathway

Lipopolysaccharide (LPS)-induced septic acute kidney injury (AKI) is determined as a devastating organ dysfunction elicited by an inappropriate response to infection with high morbidity and mortality rates. Previous evidence has illustrated an indispensable role of mitochondrial aldehyde dehydrogenase 2 (ALDH2) in the pathogenesis of sepsis-induced multiorgan abnormalities. Specifically, this study investigated the potential role of ALDH2 in sepsis-induced AKI. After LPS administration, we observed a significant decline in renal function, increased inflammatory cytokines, oxidative stress, 4-hydroxy-2-nonenal (4-HNE) accumulation, and apoptosis via MAPK activation in ALDH2^-/- mice; in contrast, pretreatment with Alda-1 (an ALDH2 activator) alleviated the LPS-induced dysfunctions in mice. Moreover, in vitro analysis revealed that ALDH2 overexpression in mouse tubular epithelial cells (mTECs) improved the inflammatory response, oxidative stress, 4-HNE accumulation, and apoptosis via MAPK inhibition, whereas ALDH2 knockdown in mTECs aggravated these parameters via MAPK activation. Therefore, ALDH2 may protect against LPS-induced septic AKI by suppressing 4-HNE/MAPK pathway.

Pinocembrin ameliorates atrial fibrillation susceptibility in rats with anxiety disorder induced by empty bottle stimulation

Background: Anxiety disorder (AD) is the most common mental disorder, which is closely related to atrial fibrillation (AF) and is considered to be a trigger of AF. Pinocembrin has been demonstrated to perform a variety of neurological and cardiac protective effects through its anti-inflammatory and antioxidant activities. The current research aims to explore the antiarrhythmic effect of pinocembrin in anxiety disorder rats and its underlying mechanisms.

Methods: 60 male Sprague-Dawley rats were distributed into four groups: CTL group: control rats + saline; CTP group: control rats + pinocembrin; Anxiety disorder group: anxiety disorder rats + saline; ADP group: anxiety disorder rats + pinocembrin. Empty bottle stimulation was conducted to induce anxiety disorder in rats for 3 weeks, and pinocembrin was injected through the tail vein for the last 2 weeks. Behavioral measurements, in vitro electrophysiological studies, biochemical assays, ELISA, Western blot and histological studies were performed to assess the efficacy of pinocembrin. In addition, HL-1 atrial cells were cultured in vitro to further verify the potential mechanism of pinocembrin.

Results: After 3 weeks of empty bottle stimulation, pinocembrin significantly improved the exploration behaviors in anxiety disorder rats. Pinocembrin alleviated electrophysiological remodeling in anxiety disorder rats, including shortening the action potential duration (APD), prolonging the effective refractory period (ERP), increasing the expression of Kv1.5, Kv4.2 and Kv4.3, decreasing the expression of Cav1.2, and ultimately reducing the AF susceptibility. These effects may be attributed to the amelioration of autonomic remodeling and structural remodeling by pinocembrin, as well as the inhibition of oxidative stress with upregulation of the nuclear factor erythroid 2-related factor 2 (Nrf2) and heme oxygenase-1 (HO-1) pathway.

Conclusion: Pinocembrin can reduce AF susceptibility in anxiety disorder rats induced by empty bottle stimulation, with the inhibition of autonomic remodeling, structural remodeling, and oxidative stress. Therefore, pinocembrin is a promising treatment for AF in patients with anxiety disorder.

The caspase-1 inhibitor VX765 upregulates connexin 43 expression and improves cell-cell communication after myocardial infarction via suppressing the IL-1β/p38 MAPK pathway

Connexin 43 (Cx43) is the most important protein in the gap junction channel between cardiomyocytes. Abnormalities of Cx43 change the conduction velocity and direction of cardiomyocytes, leading to reentry and conduction block of the myocardium, thereby causing arrhythmia. It has been shown that IL-1β reduces the expression of Cx43 in astrocytes and cardiomyocytes in vitro. However, whether caspase-1 and IL-1β affect connexin 43 after myocardial infarction (MI) is uncertain. In this study we investigated the effects of VX765, a caspase-1 inhibitor, on the expression of Cx43 and cell-to-cell communication after MI. Rats were treated with VX765 (16 mg/kg, i.v.) 1 h before the left anterior descending artery (LAD) ligation, and then once daily for 7 days. The ischemic heart was collected for histochemical analysis and Western blot analysis. We showed that VX765 treatment significantly decreased the infarct area, and alleviated cardiac dysfunction and remodeling by suppressing the NLRP3 inflammasome/caspase-1/IL-1β expression in the heart after MI. In addition, VX765 treatment markedly raised Cx43 levels in the heart after MI. In vitro experiments were conducted in rat cardiac myocytes (RCMs) stimulated with the supernatant from LPS/ATP-treated rat cardiac fibroblasts (RCFs). Pretreatment of the RCFs with VX765 (25 μM) reversed the downregulation of Cx43 expression in RCMs and significantly improved intercellular communication detected using a scrape-loading/dye transfer assay. We revealed that VX765 suppressed the activation of p38 MAPK signaling in the heart tissue after MI as well as in RCMs stimulated with the supernatant from LPS/ATP-treated RCFs. Taken together, these data show that the caspase-1 inhibitor VX765 upregulates Cx43 expression and improves cell-to-cell communication in rat heart after MI via suppressing the IL-1β/p38 MAPK pathway.

Pinocembrin polymeric micellar drug delivery system: preparation, characterisation and anti-hyperuricemic activity evaluation

Aim: Hydrophobic pinocembrin (PCB) was incorporated into a new nano-drug delivery system to enhance solubility, bioavailability and anti-hyperuricemic activity of the drug.Methods: We fabricated PCB loaded polymeric micelles (PCB-FPM) by thin film dispersion method and appropriately determined their physical characteristics. The oral relative bioavailability and anti-hyperuricemic activity of PCB-FPM and free PCB were observed.Results: The optimum particle size of the micelles was 19.90 ± 0.93 nm. PCB-FPM exhibited great stability within 18 days, coupled with lower cytotoxicity and higher biocompatibility. Moreover, the percent cumulative release of PCB-FPM was much higher than free PCB in the dissolution media. The oral bioavailability of PCB-FPM was increased by 2.61 times compared with free PCB. Uric acid (UA) level of rats was reduced in PCB-FPM group (200 mg/kg) by 78.82% comparable to the model control.Conclusion: PCB-FPM may become an ideal strategy to increase oral in-vivo availability and anti-hyperuricemic activity of PCB.

Pinocembrin ameliorates lipopolysaccharide‑induced HK‑2 cell apoptosis and inflammation by regulating endoplasmic reticulum stress

Pinocembrin (PINO) is a natural flavonoid drug that possesses a range of biological activities, including antimicrobial, antioxidant and anti-inflammatory activities. The specific aim of the present study was to examine the pharmacological role of PINO in sepsis-mediated acute kidney injury (AKI), as well as to investigate the potential underlying mechanism. Human renal tubular epithelial cells (of the HK-2 cell line) were stimulated with lipopolysaccharide (LPS) for 24 h to simulate septic AKI in vitro, after which the experiments were repeated and the cells were pretreated with increasing concentrations of PINO (0, 50, 100 and 200 µg/ml). Using an MTT cell viability assay, PINO was revealed to be non-toxic to HK-2 cells. In LPS-treated HK-2 cells, PINO alleviated the loss of cell viability. Western blotting was used to analyze the expression levels of pro-inflammatory cytokines, including IL-1β, IL-6 and TNF-α, and the results revealed that PINO decreased the expression levels of these cytokines in a concentration-dependent manner. Furthermore, malondialdehyde (MDA) and glutathione (GSH) activities were assessed using MDA and GSH assay kits and it was revealed that PINO decreased the significantly increased level of malondialdehyde, while it also decreased the reduction in the level of GSH in LPS-challenged HK-2 cells. In addition, a TUNEL assay and western blotting were performed to examine cell apoptosis, and PINO was identified to significantly inhibit the level of apoptosis in LPS-induced HK-2 cells. Subsequently, the expression levels of endoplasmic reticulum stress (ERS)-associated factors, including activating transcription factor 4, C/EBP homologous protein and phosphorylated/total eukaryotic translation initiation factor 2 subunit 1 were examined by western blotting and it was demonstrated that ERS was triggered in HK-2 cells exposed to LPS, although this was partly circumvented through PINO treatment in a concentration-dependent manner. Furthermore, after the addition of tunicamycin, which acts as an agonist of ERS, the aforementioned experiments were performed again. Tunicamycin led to partial abolition of the protective function of PINO against inflammation, oxidative stress and apoptosis in LPS-challenged HK-2 cells. Overall, the results of the present study demonstrated that PINO was able to ameliorate the injuries sustained by LPS-challenged HK-2 cells via modulating ERS to reduce inflammation, oxidative stress and apoptosis; therefore, PINO may be a novel candidate drug for treating septic AKI.

Ferrostatin-1 alleviates lipopolysaccharide-induced cardiac dysfunction

Cardiac dysfunction is a common complication of sepsis, and is attributed to severe inflammatory responses. Ferroptosis is reported to be involved in sepsis-induced cardiac inflammation. Therefore, we speculated that ferrostatin-1 (Fer-1), a ferroptosis inhibitor, improves cardiac dysfunction caused by sepsis. An intraperitoneal injection of lipopolysaccharide (LPS) was performed to induce a rat cardiac dysfunction model. Echocardiography, cardiac histopathology, biochemical and western blot results were analyzed. Twelve hours after the LPS injection, LPS-treated rats exhibited deteriorating cardiac systolic function, increased levels of cardiac injury markers and levels of ferroptosis markers prostaglandin endoperoxide synthase 2 (PTGS2). Additionally, LPS increased iron deposition in the myocardium, with downregulating ferroportin (FPN, SLC40A1) and transferrin receptor (TfR)expression, and upregulating ferritin light chain (FTL) and ferritin heavy chain (FTH1) expression. Meanwhile, LPS also increased lipid peroxidation in the rat heart by decreasing the expression of glutathione peroxidase 4 (GPX4). Moreover, the expression of inflammatory cytokines, such as tumor necrosis-alpha (TNF-α), interleukin-1 (IL-1β), and interleukin-6 (IL-6), and inflammatory cell infiltration were also increased following LPS challenge. Finally, the abovementioned adverse effects of LPS were relieved by Fer-1 except for TfR expression. Mechanistically, Fer-1 significantly reduced the levels of toll-like receptor 4 (TLR4), phospho-nuclear factor kappa B (NF-κB), and phospho-inhibitor of kappa Bα (IκBα) in LPS-treated rats. In summary, these findings imply that Fer-1 improved sepsis-induced cardiac dysfunction at least partially via the TLR4/NF-κB signaling pathway.