Attenuation of Na/K-ATPase/Src/ROS amplification signal pathway with pNaktide ameliorates myocardial ischemia-reperfusion injury

Adenosine triphosphate-induced cell death in heart failure: Is there a link?

Heart failure (HF) has emerged as one of the foremost global health threats due to its intricate pathophysiological mechanisms and multifactorial etiology. Adenosine triphosphate (ATP)-induced cell death represents a novel form of regulated cell deaths, marked by cellular energy depletion and metabolic dysregulation stemming from excessive ATP accumulation, identifying its uniqueness compared to other cell death processes modalities such as programmed cell death and necrosis. Growing evidence suggests that ATP-induced cell death (AICD) is predominantly governed by various biological pathways, including energy metabolism, redox homeostasis and intracellular calcium equilibrium. Recent research has shown that AICD is crucial in HF induced by pathological conditions like myocardial infarction, ischemia-reperfusion injury, and chemotherapy. Thus, it is essential to investigate the function of AICD in the pathogenesis of HF, as this may provide a foundation for the development of targeted therapies and novel treatment strategies. This review synthesizes current advancements in understanding the link between AICD and HF, while further elucidating its involvement in cardiac remodeling and HF progression.

The Na/K-ATPase α1/Src Signaling Axis Regulates Mitochondrial Metabolic Function and Redox Signaling in Human iPSC-Derived Cardiomyocytes

Na/K-ATPase (NKA)-mediated regulation of Src kinase, which involves defined amino acid sequences of the NKA α1 polypeptide, has emerged as a novel regulatory mechanism of mitochondrial function in metazoans. Mitochondrial metabolism ensures adequate myocardial performance and adaptation to physiological demand. It is also a critical cellular determinant of cardiac repair and remodeling. To assess the impact of the proposed NKA/Src regulatory axis on cardiac mitochondrial metabolic function, we used a gene targeting approach in human cardiac myocytes. Human induced pluripotent stem cells (hiPSC) expressing an Src-signaling null mutant (A420P) form of the NKA α1 polypeptide were generated using CRISPR/Cas9-mediated genome editing. Total cellular Na/K-ATPase activity remained unchanged in A420P compared to the wild type (WT) hiPSC, but baseline phosphorylation levels of Src and ERK1/2 were drastically reduced. Both WT and A420P mutant hiPSC readily differentiated into cardiac myocytes (iCM), as evidenced by marker gene expression, spontaneous cell contraction, and subcellular striations. Total NKA α1-3 protein expression was comparable in WT and A420P iCM. However, live cell metabolism assessed functionally by Seahorse extracellular flux analysis revealed significant reductions in both basal and maximal rates of mitochondrial respiration, spare respiratory capacity, ATP production, and coupling efficiency. A significant reduction in ROS production was detected by fluorescence imaging in live cells, and confirmed by decreased cellular protein carbonylation levels in A420P iCM. Taken together, these data provide genetic evidence for a role of NKA α1/Src in the tonic stimulation of basal mitochondrial metabolism and ROS production in human cardiac myocytes. This signaling axis in cardiac myocytes may provide a new approach to counteract mitochondrial dysfunction in cardiometabolic diseases.

Inhibitory mechanism of quercetin on Alicyclobacillus acidoterrestris

In this the antibacterial of quercetin against Alicyclobacillus acidoterrestris was evaluated by measuring the minimal inhibitory concentration (MIC) and minimal bactericidal concentration (MBC). Subsequently, the effect of quercetin on A. acidoterrestris cell membrane was evaluated through scanning electron microscopy (SEM), surface hydrophobicity determination, diacetate fluorescein staining and propidium iodide (PI) staining. Additionally, the effects of quercetin on intracellular macromolecules and cell metabolism were explored by measuring the culture medium protein, bacterial protein and intracellular sodium and potassium adenosine triphosphate (ATP) enzyme activity. The results revealed that quercetin exhibited the MIC and MBC values of 100 ug/mL and 400 ug/mL, respectively, against A. acidoterrestris. The SEM results revealed that quercetin could induce irreversible damage to the cell membrane effectively. Moreover, quercetin could enhance the surface hydrophobicity of A. acidoterrestris. The results of flow cytometry and fluorescence microscopy analyses revealed that quercetin could promote cell damage by altering the cell membrane permeability of A. acidoterrestris, inducing the release of nucleic acid substances from the cells. Furthermore, the determination of protein content in the culture medium, bacterial protein content, and the Na(+)/K(+)-ATPase activity demonstrated that quercetin could reduce the intracellular protein content and impedes protein expression and ATPase synthesis effectively, leading to apoptosis.

Src tyrosine kinase promotes cardiac remodeling induced by chronic sympathetic activation

Cardiac remodeling serves as the underlying pathological basis for numerous cardiovascular diseases and represents a pivotal stage for intervention. The excessive activation of β-adrenergic receptors (β-ARs) assumes a crucial role in cardiac remodeling. Nonetheless, the underlying molecular mechanisms governing β-AR-induced cardiac remodeling remain largely unresolved. In the present study, we identified Src tyrosine kinase as a key player in the cardiac remodeling triggered by excessive β-AR activation. Our findings demonstrated that Src mediates isoproterenol (ISO)-induced cardiac hypertrophy, fibrosis, and inflammation in vivo. Furthermore, Src facilitates β-AR-mediated proliferation and transdifferentiation of cardiac fibroblasts, and hypertrophy and cardiomyocytes in vitro. Subsequent investigations have substantiated that Src mediates β-AR induced the extracellular signal-regulated protein kinase (ERK1/2) signaling pathway activated by β-AR. Our research presents compelling evidence that Src promotes β-AR-induced cardiac remodeling in both in vivo and in vitro settings. It establishes the promoting effect of the β-AR/Src/ERK signaling pathway on overall cardiac remodeling in cardiac fibroblasts and underscores the potential of Src as a therapeutic target for cardiac remodeling.

Myocardial ischemia-reperfusion injury; Molecular mechanisms and prevention

Cardiovascular diseases are one of the leading causes of mortality in developed countries. Among cardiovascular disorders, myocardial infarction remains a life-threatening problem predisposing to the development and progression of ischemic heart failure. Ischemia/reperfusion (I/R) injury is a critical cause of myocardial injury. In recent decades, many efforts have been made to find the molecular and cellular mechanisms underlying the development of myocardial I/R injury and post-ischemic remodeling. Some of these mechanisms are mitochondrial dysfunction, metabolic alterations, inflammation, high production of ROS, and autophagy deregulation. Despite continuous efforts, myocardial I/R injury remains a major challenge in medical treatments of thrombolytic therapy, heart disease, primary percutaneous coronary intervention, and coronary arterial bypass grafting. The development of effective therapeutic strategies to reduce or prevent myocardial I/R injury is of great clinical significance.

Meta-data analysis of kidney stone disease highlights ATP1A1 involvement in renal crystal formation

Nephrolithiasis is a complicated disease affected by various environmental and genetic factors. Crystal-cell adhesion is a critical initiation process during kidney stone formation. However, genes regulated by environmental and genetic factors in this process remain unclear. In the present study, we integrated the gene expression profile data and the whole-exome sequencing data of patients with calcium stones, and found that ATP1A1 might be a key susceptibility gene involved in calcium stone formation. The study showed that the T-allele of rs11540947 in the 5'-untranslated region of ATP1A1 was associated with a higher risk of nephrolithiasis and lower activity of a promoter of ATP1A1. Calcium oxalate crystal deposition decreased ATP1A1 expression in vitro and in vivo and was accompanied by the activation of the ATP1A1/Src/ROS/p38/JNK/NF-κB signaling pathway. However, the overexpression of ATP1A1 or treatment with pNaKtide, a specific inhibitor of the ATP1A1/Src complex, inhibited the ATP1A1/Src signal system and alleviated oxidative stress, inflammatory responses, apoptosis, crystal-cell adhesion, and stone formation. Moreover, the DNA methyltransferase inhibitor 5-aza-2'-deoxycytidine reversed ATP1A1 down-regulation induced by crystal deposition. In conclusion, this is the first study to show that ATP1A1, a gene modulated by environmental factors and genetic variations, plays an important role in renal crystal formation, suggesting that ATP1A1 may be a potential therapeutic target for treating calcium stones.

A newly developed consortium with a highly efficient thiocyanate degradation capacity: A comprehensive investigation of the degradation and detoxification potential

Thiocyanate-containing wastewater harms ecosystems and can cause serious damage to animals and plants, so it is urgent to treat it effectively. In this study, a new efficient thiocyanate-degrading consortium was developed and its degradation characteristics were studied. It was found that up to 154.64 mM thiocyanate could be completely degraded by this consortium over 6 days of incubation, with a maximum degradation rate of 1.53 mM h^-1. High-throughput sequencing analysis showed that Thiobacillus (77.78%) was the predominant thiocyanate-degrading bacterial genus. Plant toxicology tests showed that the germination index of mung bean and rice seeds cultured with media obtained after thiocyanate degradation by the consortium increased by 94% and 84.83%, respectively, compared with the control group without thiocyanate degradation. Cytotoxicity tests showed that thiocyanate without degradation significantly decreased the Neuro-2a cell activity and mitochondrial membrane potential; induced reactive oxygen species generation and apoptosis; increased the cellular Ca²⁺ concentration; and damaged the cell nucleus and DNA. Furthermore, the thiocyanate degradation products produced the consortium were almost totally non-toxic, revealing the same characteristics as those of the control using distilled water. This study shows that the consortium has a high degradation efficiency and detoxification characteristics, as well as great application potential in bioremediation of industrial thiocyanate-containing wastewater.

The combination of sodium alginate and chlorogenic acid enhances the therapeutic effect on ulcerative colitis by the regulation of inflammation and the intestinal flora

Chlorogenic acid (CA) and sodium alginate (SA) each have good therapeutic effects on ulcerative colitis (UC) owing to their antioxidant and anti-inflammatory activity. This study aimed to investigate the effects of CA alone and in combination with SA on inflammatory cells and UC mice. In the Lipopolysaccharide (LPS)-induced RAW 264.7 inflammatory cell model, Nitric oxide (NO) and interleukin-6 (IL-6) levels were significantly lower after treatment with CA plus SA than with CA alone. In the DSS-induced UC mouse model, compared with CA alone, CA plus SA showed a better ability to alleviate weight loss, reduce the disease activity index (DAI), improve the colonic mucosa, reduce the expression of inflammatory factors in the serum and myeloperoxidase (MPO) in colonic tissue, increase superoxide dismutase (SOD) levels, protect the intestinal mucosa and regulate the abundance of Actinobacteriota, Lactobacillus, Bifidobacterium, Bacteroides, Subdoligranulum and Streptococcus. Thus, CA plus SA can improve the therapeutic efficacy of CA in UC by regulating inflammatory factors, oxidative stress, and the intestinal flora and by protecting ulcerative wounds. These findings broaden our understanding of the role of the combination of SA and CA in enhancing the effects of CA on UC and provide strategies for prevention and treatment.

Periplocin ameliorates mouse age-related meibomian gland dysfunction through up-regulation of Na/K-ATPase via SRC pathway

Age-related meibomian gland dysfunction (MGD) is the main cause of evaporative dry eye disease in an aging population. Decreased meibocyte cell renewal and lipid synthesis are associated with age-related MGD. Here, we found an obvious decline of Ki67, ΔNp63, and Na+/K+ ATPase expression in aged meibomian glands. Potential Na+/K+ ATPase agonist periplocin, a naturally occurring compound extracted from the traditional herbal medicine cortex periplocae, could promote the proliferation and stem cell activity of meibocyte cells in vitro. Moreover, we observed that periplocin treatment effectively increased the expression of Na+ /K+ ATPase, accompanied with the enhanced expression of Ki67 and ΔNp63 in aged meibomian glands, indicating that periplocin may accelerate meibocyte cell renewal in aged mice. LipidTox staining showed increased lipid accumulation after periplocin treatment in cultured meibomian gland cells and aged meibomian glands. Furthermore, we demonstrated that the SRC pathway was inhibited in aged meibomian glands; however, it was activated by periplocin. Accordingly, the inhibition of the SRC signaling pathway by saracatinib blocked periplocin-induced proliferation and lipid accumulation in meibomian gland cells. In sum, we suggest periplocin-ameliorated meibocyte cell renewal and lipid synthesis in aged meibomian glands via the SRC pathway, which could be a promising candidate for age-related MGD.

Target Characterization of Kaempferol against Myocardial Infarction Using Novel In Silico Docking and DARTS Prediction Strategy

Target identification is a crucial process for advancing natural products and drug leads development, which is often the most challenging and time-consuming step. However, the putative biological targets of natural products obtained from traditional prediction studies are also informatively redundant. Thus, how to precisely identify the target of natural products is still one of the major challenges. Given the shortcomings of current target identification methodologies, herein, a novel in silico docking and DARTS prediction strategy was proposed. Concretely, the possible molecular weight was detected by DARTS method through examining the protected band in SDS-PAGE. Then, the potential targets were obtained from screening and identification through the PharmMapper Server and TargetHunter method. In addition, the candidate target Src was further validated by surface plasmon resonance assay, and the anti-apoptosis effects of kaempferol against myocardial infarction were further confirmed by in vitro and in vivo assays. Collectively, these results demonstrated that the integrated strategy could efficiently characterize the targets, which may shed a new light on target identification of natural products.

A Novel Peptide Ameliorates TNFα- and LPS-Induced Endothelia Dysfunction in Preeclampsia

BACKGROUND

To investigate the protective effects of the novel peptide antiendothelial dysfunction peptide in preeclampsia (AEDPPE) on tumor necrosis factor α (TNFα)- and lipopolysaccharide (LPS)-induced injury in the vascular endothelium in preeclampsia.

METHODS

The effects of AEDPPE on TNFα-induced vascular endothelial injury were assessed by enzyme-linked immunosorbent assay, quantitative real-time PCR, mitochondrial membrane potential assay, Cell Counting Kit-8 assay, THP-1 monocyte-human umbilical vein endothelial cell (HUVEC) adhesion assay, endothelial tube-forming assay, transcriptomic analysis, preeclamptic symptom analysis, and histological analysis in preeclampsia-like rat models induced by LPS.

RESULTS

AEDPPE alleviated the upregulation of antiangiogenic factors including soluble fms-like tyrosine kinase-1, endothelin-1, and tissue plasminogen activator and attenuated the reduction in mitochondrial potential induced by TNFα in HUVECs. In addition, AEDPPE treatment counteracted the decrease in tube formation and decreased the numbers of THP-1 monocytes attached to HUVECs caused by TNFα. Mechanistically, cytokine-cytokine receptor interactions enriched many genes and the TNF signaling pathway may be involved in this phenomenon. Moreover, cotreatment with LPS and AEDPPE significantly reversed the preeclampsia-like phenotype including hypertension and proteinuria and improved the functions of the kidney and placenta.

CONCLUSIONS

AEDPPE effectively ameliorated the vascular endothelial injury induced by TNFα and LPS in preeclampsia. We suggest that AEDPPE may be a novel therapeutic candidate for preeclampsia treatment. These findings demonstrate that AEDPPE may play an effective role in ameliorating vascular endothelial dysfunction and be a potential therapeutic agent for preeclampsia.

Anastatin Derivatives Alleviate Myocardial Ischemia-Reperfusion Injury via Antioxidative Properties

(±)-Anastatins A and B are flavonoids isolated from Anastatica hierochuntica. In a previous study, twenty-four di- and tri-substituted novel derivatives of anastatins were designed and their preliminary antioxidant activities were evaluated. In the present study, the protective effect of myocardial ischemia-reperfusion (I/R) and the systematic antioxidant capacity of 24 derivatives were further studied. Compound 13 was the most potent among all the compounds studied, which increased the survival of H9c2 cells to 80.82%. The antioxidant capability of compound 13 was evaluated in ferric reducing antioxidant power, 2,2'-azino-bis (3-ethylbenzothiazoline-6-sulfonic acid) radical scavenging, and 2,2-diphenyl-1-picrylhydrazyl assays. It was observed that compound 13 significantly reduced infarcted areas and improved histopathological and electrocardiogram changes in rats with myocardial I/R injury. Moreover, compound 13 decreased the leakage rates of serum lactate dehydrogenase, creatine kinase, and malonyldialdehyde from rat myocardial tissues and increased the level of glutathione and superoxide dismutase activities following myocardial I/R injury in rats. Taken together, we concluded that compound 13 had potent cardioprotective effects against myocardial I/R injury both in vitro and in vivo owing to its extensive antioxidant activities.

The Na/K-ATPase α1/Src interaction regulates metabolic reserve and Western diet intolerance

AIM

Highly prevalent diseases such as insulin resistance and heart failure are characterized by reduced metabolic flexibility and reserve. We tested whether Na/K-ATPase (NKA)-mediated regulation of Src kinase, which requires two NKA sequences specific to the α1 isoform, is a regulator of metabolic capacity that can be targeted pharmacologically.

METHODS

Metabolic capacity was challenged functionally by Seahorse metabolic flux analyses and glucose deprivation in LLC-PK1-derived cells expressing Src binding rat NKA α1, non-Src-binding rat NKA α2 (the most abundant NKA isoform in the skeletal muscle), and Src binding gain-of-function mutant rat NKA α2. Mice with skeletal muscle-specific ablation of NKA α1 (skα1-/-) were generated using a MyoD:Cre-Lox approach and were subjected to treadmill testing and Western diet. C57/Bl6 mice were subjected to Western diet with or without pharmacological inhibition of NKA α1/Src modulation by treatment with pNaKtide, a cell-permeable peptide designed by mapping one of the sites of NKA α1/Src interaction.

RESULTS

Metabolic studies in mutant cell lines revealed that the Src binding regions of NKA α1 are required to maintain metabolic reserve and flexibility. Skα1-/- mice had decreased exercise endurance and mitochondrial Complex I dysfunction. However, skα1-/- mice were resistant to Western diet-induced insulin resistance and glucose intolerance, a protection phenocopied by pharmacological inhibition of NKA α1-mediated Src regulation with pNaKtide.

CONCLUSIONS

These results suggest that NKA α1/Src regulatory function may be targeted in metabolic diseases. Because Src regulatory capability by NKA α1 is exclusive to endotherms, it may link the aerobic scope hypothesis of endothermy evolution to metabolic dysfunction.

miR‑130b regulates PTEN to activate the PI3K/Akt signaling pathway and attenuate oxidative stress‑induced injury in diabetic encephalopathy

Diabetic encephalopathy (DE) is one of the main chronic complications of diabetes, and is characterized by cognitive defects. MicroRNAs (miRNAs/miRs) are widely involved in the development of diabetes-related complications. The present study evaluated the role of miR-130b in DE and investigated its mechanisms of action. PC12 cells and hippocampal cells were exposed to a high glucose environment to induce cell injuries to mimic the in vitro model of DE. Cells were transfected with miR-130b mimic, miR-130b inhibitor and small interfering RNA (si)-phosphatase and tensin homolog (PTEN) to evaluate the protective effect of the miR-130b/PTEN axis against oxidative stress in high glucose-stimulated cells involving Akt activity. Furthermore, the effect of agomir-130b was also assessed on rats with DE. The expression of miR-130b was reduced in the DE models in vivo and in vitro. The administration of miR-130b mimic increased the viability of high glucose-stimulated cells, prevented apoptosis, increased the activity of superoxide dismutase (SOD), decreased the malondialdehyde (MDA) content, activated Akt protein levels and inhibited the mitochondria-mediated apoptotic pathway. The administration of miR-130b inhibitor exerted opposite effects, while si-PTEN reversed the effects of miR-130b inhibitor. In vivo, the administration of agomir-130b attenuated cognitive disorders and neuronal damage, increased SOD activity, reduced the MDA content, activated Akt protein levels and inhibited the mitochondria-mediated apoptosis pathway in rats with DE. On the whole, these results suggest that miR-130b activates the PI3K/Akt signaling pathway to exert protective effects against oxidative stress injury via the regulation of PTEN in rats with DE.

Does Src Kinase Mediated Vasoconstriction Impair Penumbral Reperfusion?

Despite successful recanalization, a significant number of patients with ischemic stroke experience impaired local brain tissue reperfusion with adverse clinical outcome. The cause and mechanism of this multifactorial complication are yet to be understood. At the current moment, major attention is given to dysfunction in blood-brain barrier and capillary blood flow but contribution of exaggerated constriction of cerebral arterioles has also been suggested. In the brain, arterioles significantly contribute to vascular resistance and thus control of perfusion. Accordingly, pathological changes in arteriolar wall function can, therefore, limit sufficient reperfusion in ischemic stroke, but this has not yet received sufficient attention. Although an increased vascular tone after reperfusion has been demonstrated in several studies, the mechanism behind it remains to be characterized. Importantly, the majority of conventional mechanisms controlling vascular contraction failed to explain elevated cerebrovascular tone after reperfusion. We propose here that the Na,K-ATPase-dependent Src kinase activation are the key mechanisms responsible for elevation of cerebrovascular tone after reperfusion. The Na,K-ATPase, which is essential to control intracellular ion homeostasis, also executes numerous signaling functions. Under hypoxic conditions, the Na,K-ATPase is endocytosed from the membrane of vascular smooth muscle cells. This initiates the Src kinase signaling pathway that sensitizes the contractile machinery to intracellular Ca²⁺ resulting in hypercontractility of vascular smooth muscle cells and, thus, elevated cerebrovascular tone that can contribute to impaired reperfusion after stroke. This mechanism integrates with cerebral edema that was suggested to underlie impaired reperfusion and is further supported by several studies, which are discussed in this article. However, final demonstration of the molecular mechanism behind Src kinase-associated arteriolar hypercontractility in stroke remains to be done.

Knockdown of lncRNA TTTY15 alleviates myocardial ischemia-reperfusion injury through the miR-374a-5p/FOXO1 axis

Myocardial ischemia/reperfusion (I/R) injury greatly contributes to myocardial tissue damage in patients with coronary disease, which eventually leads to heart failure. Long noncoding RNAs (lncRNAs) have an emerging role in the process of myocardial I/R injury. Our previous work revealed the protective role of miR-374a-5p against myocardial I/R injury. In this study, we explored the role of lncRNA TTTY15 and its potential interaction mechanisms with miR-374a-5p in myocardial I/R injury. The expression of TTTY15 was increased both in vitro and in vivo after myocardial I/R injury models according to quantitative real-time polymerase chain reaction. Various assays were conducted to evaluate the regulatory relationship among TTTY15, miR-374a-5p, FOXO1, and autophagy in H9c2 and HL-1 cells. The results showed that TTTY15 suppresses autophagy and myocardial I/R injury by targeting miR-374a-5p. We found that TTTY15 regulates miR-374a-5p, thus affecting FOXO1 expression and autophagy in myocytes during I/R. Furthermore, in an in vivo mouse model of myocardial I/R injury, suppression of TTTY15 successfully alleviated myocardial I/R injury. Our results reveal a novel feedback mechanism in which TTTY15 regulates miRNA processing and a potential target in myocardial I/R injury. TTTY15 is a promising therapeutic target for treating myocardial I/R injury.

The Pivotal Role of Adipocyte-Na K peptide in Reversing Systemic Inflammation in Obesity and COVID-19 in the Development of Heart Failure

This review summarizes data from several laboratories that have demonstrated a role of the Na/K-ATPase, specifically its α1 subunit, in the generation of reactive oxygen species (ROS) via the negative regulator of Src. Together with Src and other signaling proteins, the Na/K-ATPase forms an oxidant amplification loop (NKAL), amplifies ROS, and participates in cytokines storm in obesity. The development of a peptide fragment of the α1 subunit, NaKtide, has been shown to negatively regulate Src. Several groups showed that the systemic administration of the cell permeable modification of NaKtide (pNaKtide) or its selective delivery to fat tissue-adipocyte specific expression of NaKtide-ameliorate the systemic elevation of inflammatory cytokines seen in chronic obesity. Severe acute respiratory syndrome - coronavirus 2 (SARS-CoV-2), the RNA Coronavirus responsible for the COVID-19 global pandemic, invades cells via the angiotensin converting enzyme 2 (ACE-2) receptor (ACE2R) that is appended in inflamed fat tissue and exacerbates the formation of the cytokines storm. Both obesity and heart and renal failure are well known risks for adverse outcomes in patients infected with COVID-19. White adipocytes express ACE-2 receptors in high concentration, especially in obese patients. Once the virus invades the white adipocyte cell, it creates a COVID19-porphyrin complex which degrades and produces free porphyrin and iron and increases ROS. The increased formation of ROS and activation of the NKAL results in a further potentiated formation of ROS production, and ultimately, adipocyte generation of more inflammatory mediators, leading to systemic cytokines storm and heart failure. Moreover, chronic obesity also results in the reduction of antioxidant genes such as heme oxygenase-1 (HO-1), increasing adipocyte susceptibility to ROS and cytokines. It is the systemic inflammation and cytokine storm which is responsible for many of the adverse outcomes seen with COVID-19 infections in obese subjects, leading to heart failure and death. This review will also describe the potential antioxidant drugs and role of NaKtide and their demonstrated antioxidant effect used as a major strategy for improving obesity and epicardial fat mediated heart failure in the context of the COVID pandemic.

Attenuation of the Na/K‑ATPase/Src/ROS amplification signaling pathway by astaxanthin ameliorates myocardial cell oxidative stress injury

The 3S, 3′S-ASTaxanthin (3S, 3′S-AST) isomer has strong antioxidant activity; however, its protective roles and potential mechanisms against oxidative stress damage in cardiomyocytes have not been investigated. Na⁺/K⁺-ATPase (NKA)/Src signal activation has an important role in increasing reactive oxygen species (ROS) production. The aim of the present study was to investigate the protective effects and mechanism of 3S, 3′S-AST on hydrogen peroxide (H₂O₂)-induced oxidative stress injury in H9c2 myocardial cells. The protective effects of 3S, 3′S-AST on H₂O₂-induced H9c2 cell injury was observed by measuring lactate dehydrogenase and creatine kinase myocardial band content, cell viability and nuclear morphology. The antioxidant effect was investigated by analyzing ROS accumulation and malondialdehyde, glutathione (GSH) peroxidase, GSH and glutathione reductase activity levels. The protein expression levels of Bax, Bcl-2, caspase-3 and cleaved caspase-3 were analyzed using western blotting to determine cardiomyocyte apoptosis. Western blot analysis of the phosphorylation levels of Src and Erk1/2 were also performed to elucidate the molecular mechanism involved. The results showed that 3S, 3′S-AST reduced the release of LDH and promoted cell viability, and attenuated ROS accumulation and cell apoptosis induced by H₂O₂. Furthermore, 3S, 3′S-AST also restored apoptosis-related Bax and Bcl-2 protein expression levels in H₂O₂-treated H9c2 cells. The phosphorylation levels of Src and Erk1/2 were significantly higher in the H₂O₂ treatment group, whereas 3S, 3′S-AST pretreatment significantly decreased the levels of phosphorylated (p)-Src and p-ERK1/2. The results provided evidence that 3S, 3′S-AST exhibited a cardioprotective effect against oxidative stress injury by attenuating NKA/Src/Erk1/2-modulated ROS amplification.

[miR-133b inhibits myocardial ischemia-reperfusion-induced cardiomyocyte apoptosis and accumulation of reactive oxygen species in rats by targeting YES1]

OBJECTIVE

To investigate the effect of miR-133b on cardiomyocyte apoptosis induced by myocardial ischemia-reperfusion (I/R) and explore the mechanism.

METHODS

Thirty-six adult SD rats were randomized into sham-operated group, I/R group, AdmiR-NC group and AdmiR-133b group, and rat models of myocardial I/R were established in the latter 3 groups with myocardial injections of saline or recombinant adenoviruses in the left ventricle. The expression of MiR-133b was detected using RT-qPCR, and cardiac function of the rats was determined using FDP 1 HRV and BRS analysis system. Serum CK-MB and cTnI levels were determined by ELISA, myocardial injury was evaluated with HE staining, cardiomocyte apoptosis was detected by flow cytometry, and ROS content was determined using a DCFH-DA probe. In the in vitro experiment, H9C2 myocardial cells with hypoxia/reoxygenation (H/R) treatment were transfected with Mir-NC or MiR-133b mimic, and the cellular expression of MiR-133b, cell apoptosis, and ROS content were determined. Dual luciferase reporter assay was performed to verify the targeting relationship between miR-133b and YES1. The effects of pc-YES1 or miR-133b mimic transfection on YES1 expression, apoptosis, and ROS content in H9C2 cells were evaluated.

RESULTS

Compared with those in I/R group, miR-133b expression was obviously up-regulated, LVEDP, cTnI and CK-MB levels were significantly decreased, and LVSP, +dp/dt, -dp/dt, HR and CF levels were increased in admiR-133b group (P < 0.01). The rats in admiR-133b group showed obviously reduced pathological damage, cell apoptosis and ROS content compared with those in I/ R group (P < 0.01). In H9C2 cells exposed to H/R, transfection with miR-133b mimic significantly up-regulated miR-133b expression and decreased cell apoptosis and ROS content (P < 0.01). The results of dual luciferase reporter assay suggested a direct targeting relationship between miR-133b and YES1, and MiR-133b mimic transfection significantly down-regulated YES1 protein expression in cells with H/R exposure (P < 0.01). Co-transfection with pc-YES1 reversed the effect of miR-133b overexpression on myocardial cell apoptosis and ROS accumulation.

CONCLUSIONS

miR-133b can inhibit I/R-induced myocardial cell apoptosis and ROS accumulation by targeting YES1 to reduce myocardial I/R injury in rats.

Peptidomics Analysis Reveals Peptide PDCryab1 Inhibits Doxorubicin-Induced Cardiotoxicity

Doxorubicin (DOX) is limited due to dose-dependent cardiotoxicity. Peptidomics is an emerging field of proteomics that has attracted much attention because it can be used to study the composition and content of endogenous peptides in various organisms. Endogenous peptides participate in various biological processes and are important sources of candidates for drug development. To explore peptide changes related to DOX-induced cardiotoxicity and to find peptides with cardioprotective function, we compared the expression profiles of peptides in the hearts of DOX-treated and control mice by mass spectrometry. The results showed that 236 differential peptides were identified upon DOX treatment, of which 22 were upregulated and 214 were downregulated. Next, we predicted that 31 peptides may have cardioprotective function by conducting bioinformatics analysis on the domains of each precursor protein, the predicted score of peptide biological activity, and the correlation of each peptide with cardiac events. Finally, we verified that a peptide (SPFYLRPPSF) from Cryab can inhibit cardiomyocyte apoptosis, reduce the production of reactive oxygen species, improve cardiac function, and ameliorate myocardial fibrosis in vitro and vivo. In conclusion, our results showed that the expression profiles of peptides in cardiac tissue change significantly upon DOX treatment and that these differentially expressed peptides have potential cardioprotective functions. Our study suggests a new direction for the treatment of DOX-induced cardiotoxicity.

Phenylethanoid glycosides of Callicarpa kwangtungensis Chun exert cardioprotective effect by weakening Na+-K+-ATPase/Src/ERK1/2 pathway and inhibiting apoptosis mediated by oxidative stress and inflammation

ETHNOPHARMACOLOGICAL RELEVANCE

Callicarpa kwangtungensis Chun (C. kwangtungensis) is a very famous herbal medicine with the function of promoting blood circulation and removing blood stasis which is beneficial for cardiovascular disease (CVD). Phenylethanoid glycosides (PGs) are the major class of active ingredients in C. kwangtungensis and present significant anti-oxidative and anti-inflammatory property related to apoptosis. Therefore, this study aimed to investigate the effects of total phenylethanoid glycosides of C. kwangtungensis (CK-PGs) on isoproterenol (ISO) induced myocardial ischemic injury (MI) and the mechanisms related to the apoptosis mediated by oxidative damage and inflammation.

METHODS

The myocardial ischemia animal model was established as subcutaneous injecting ISO. Echocardiography and biomarkers were employed to determine the degree of myocardial damage. Histopathological changes were observed by hematoxylin and eosin test. The TUNEL staining and activity of caspase-3 were measured to detect the level of apoptosis which is medicated by the oxidative damage detected by the level of MDA, GSH and ROS tested with the kit and the inflammation reflected by TNF-α. The activity of Na⁺-K⁺-ATPase (NKA) was detected by the commercial kits, whose expression was measured by immunohistochemistry analysis. At last, Western blot analysis was used to measure Na⁺-K⁺-ATPase/Src/ERK1/2 and Bax/Bcl-2 pathway.

RESULTS

CK-PGs showed cardioprotective effect against ISO-induced myocardial ischemic injury evidenced by improving heart function and lowering myocardial injury markers. CK-PGs could inhibit the level of apoptosis as shown by the decrease of the TUNEL-positive cells, the activity of caspase-3 and increase of the expression of Bax. CK-PGs also reduced oxidative stress and inflammation to suppress apoptosis by decreasing the level of ROS, MDA, and increasing GSH activity and lowering the level of TNF-α. In addition, CK-PGs exerted the protection by increasing the activity and the expression of NKA. Meanwhile, Na⁺-K⁺-ATPase/Src/ERK1/2pathway was weakened for the inhibition of apoptosis.

CONCLUSIONS

CK-PGs could protect cardiomyocytes from myocardial injury through suppressing Na⁺-K⁺-ATPase/Src/ERK1/2 pathway and inhibiting apoptosis mediated by oxidative stress and inflammation.

Central Role for Adipocyte Na,K-ATPase Oxidant Amplification Loop in the Pathogenesis of Experimental Uremic Cardiomyopathy

BACKGROUND

Oxidative stress in adipocyte plays a central role in the pathogenesis of obesity as well as in the associated cardiovascular complications. The putative uremic toxin indoxyl sulfate induces oxidative stress and dramatically alters adipocyte phenotype in vitro. Mice that have undergone partial nephrectomy serve as an experimental model of uremic cardiomyopathy. This study examined the effects on adipocytes of administering a peptide that reduces oxidative stress to the mouse model.

METHODS

A lentivirus vector introduced the peptide NaKtide with an adiponectin promoter into the mouse model of experimental uremic cardiomyopathy, intraperitoneally. Then adipocyte-specific expression of the peptide was assessed for mice fed a standard diet compared with mice fed a western diet enriched in fat and fructose.

RESULTS

Partial nephrectomy induced cardiomyopathy and anemia in the mice, introducing oxidant stress and an altered molecular phenotype of adipocytes that increased production of systemic inflammatory cytokines instead of accumulating lipids, within 4 weeks. Consumption of a western diet significantly worsened the adipocyte oxidant stress, but expression of NaKtide in adipocytes completely prevented the worsening. The peptide-carrying lentivirus achieved comparable expression in skeletal muscle, but did not ameliorate the disease phenotype.

CONCLUSIONS

Adipocyte-specific expression of NaKtide, introduced with a lentiviral vector, significantly ameliorated adipocyte dysfunction and uremic cardiomyopathy in partially nephrectomized mice. These data suggest that the redox state of adipocytes controls the development of uremic cardiomyopathy in mice subjected to partial nephrectomy. If confirmed in humans, the oxidative state of adipocytes may be a therapeutic target in chronic renal failure.

Chemical Composition and Anti-Alzheimer's Disease-Related Activities of a Functional Oil from the Edible Seaweed Hizikia fusiforme

Cholinergic disorder, oxidative stress, and neuroinflammation play important roles in the pathology of Alzheimer's disease. To explore the healthy potential of the edible seaweed Hizikia fusiforme on this aspect, a functional oil (HFFO) was extracted from this alga and investigated on its constituents by gas chromatography-mass spectrometry (GC/MS) in this study. Its anti-Alzheimer's related bioactivities including acetylcholinesterase (AChE) inhibition, antioxidation, and anti-neuroinflammation were evaluated, traced, and simulated by in vitro and in silico methods. GC/MS analysis indicated that HFFO mainly contained arachidonic acid (ARA), 11,14,17-eicosatrienoic acid (ETrA), palmitic acid, phytol, etc. HFFO showed moderate AChE inhibition and antioxidant activity. Bioactivity tracing using commercial standards verified that AChE inhibition of HFFO mainly originated from ARA and ETrA, whereas antioxidant activity mainly from ARA. Lineweaver-Burk plots showed that both ARA and ETrA are noncompetitive AChE inhibitors. A molecular docking study demonstrated low CDOCKER interaction energy of -26.33 kcal/mol for ARA and -43.70 kcal/mol for ETrA when interacting with AChE and multiple interactions in the ARA (or ETrA)-AChE complex. In the anti-neuroinflammatory evaluation, HFFO showed no toxicity toward BV-2 cells at 20 μg/mL and effectively inhibited the production of nitroxide and reduced the level of reactive oxygen species in lipopolysaccharide-induced BV-2 cells. The results indicated that HFFO could be used in functional foods for its anti-Alzheimer's disease-related activities.

A caveolin binding motif in Na/K-ATPase is required for stem cell differentiation and organogenesis in mammals and C. elegans

Several signaling events have been recognized as essential for regulating cell lineage specification and organogenesis in animals. We find that the gain of an amino-terminal caveolin binding motif (CBM) in the α subunit of the Na/K-adenosine triphosphatase (ATPase) (NKA) is required for the early stages of organogenesis in both mice and Caenorhabditis elegans. The evolutionary gain of the CBM occurred at the same time as the acquisition of the binding sites for Na+/K+. Loss of this CBM does not affect cell lineage specification or the initiation of organogenesis, but arrests further organ development. Mechanistically, this CBM is essential for the dynamic operation of Wnt and the timely up-regulation of transcriptional factors during organogenesis. These results indicate that the NKA was evolved as a dual functional protein that works in concert with Wnt as a hitherto unrecognized common mechanism to enable stem cell differentiation and organogenesis in multicellular organisms within the animal kingdom.

Panax Notoginseng Saponins Attenuate Myocardial Ischemia-Reperfusion Injury Through the HIF-1α/BNIP3 Pathway of Autophagy

BACKGROUND AND OBJECTIVE

Panax Notoginseng Saponins (PNS) is a formula of Chinese medicine commonly used for treating ischemia myocardial in China. However, its mechanism of action is yet unclear. This study investigated the effect and the mechanism of PNS on myocardial ischemia-reperfusion injury (MIRI) through the hypoxia-inducible factor 1α (HIF-1α)/bcl-2/adenovirus E1B19kDa-interacting protein3 (BNIP3) pathway of autophagy.

METHODS

We constructed a rat model of myocardial injury and compared among 4 groups (n = 10, each): the sham-operated group (Sham), the ischemia-reperfusion group (IR), the PNS low-dose group, and the PNS high-dose group were pretreated with PNS (30 and 60 mg/kg, respectively). Serum creatine kinase, malonaldehyde (MDA), lactate dehydrogenase, myocardial tissue superoxide dismutase, and reactive oxygen species were detected in rats with myocardial ischemia-reperfusion after the intervention of PNS. The rat myocardial tissue was examined using hematoxylin and eosin (H&E) staining, and the mitochondria of myocardial cells were observed using transmission electron microscopy. The expressions of microtubule-associated protein light chain 3 (LC3), HIF-1α, BNIP3, Beclin-1, and autophagy-related gene-5 (Atg5) in rat myocardial tissue were detected using Western blotting.

RESULTS

The results showed that PNS was significantly protected against MIRI, as evidenced by the decreasing in the concentration of serum CK, MDA, lactate dehydrogenase, and myocardial tissue superoxide dismutase, reactive oxygen species, the attenuation of myocardial tissue histopathological changes and the mitochondrial damages of myocardial cells, and the increase of mitochondria autophagosome in myocardial cells. In addition, PNS significantly increased the expression of LC3 and the ratio of LC3II/LC3I in rat myocardial tissue. Moreover, PNS significantly increased the expression of HIF-1α, BNIP3, Atg5, and Beclin-1 in rat myocardial tissue.

CONCLUSIONS

The protective effect of PNS on MIRI was mainly due to its ability to enhance the mitochondrial autophagy of myocardial tissue through the HIF-1α/BNIP3 pathway.

Ginkgetin aglycone attenuates the apoptosis and inflammation response through nuclear factor-kB signaling pathway in ischemic-reperfusion injury

AIMS

Acute myocardial infarction (AMI) is one of the most threaten disease in the world. Ginkgetin aglycone (GA) was a new kind of Ginkgo biloba, involved in various diseases, including kidney injury and acute pancreatitis. However, the function of GA in AMI remains unknown. The aim of the study was to investigate the characteristics and function of GA in ischemic-reperfusion injury.

METHODS

H₂ O ₂ - and CoCl ₂ -treated H9C2 cells were used to analyze the function of GA in vitro. Caspase 3, interleukin-6 (IL-6), and tumor necrosis factor-α were detected to evaluate the apoptosis and inflammation response. Rat AMI was performed to elucidate the function in vivo.

RESULTS

We found that GA could reduce the apoptosis and improved cell survival of H₂ O ₂ -treated H9C2 cardiomyocytes and CoCl ₂ -treated H9C2 cells. GA attenuated CoCl ₂ -induced inflammatory response and the level of cleaved caspase 33, suggesting that GA could alleviate the cell apoptosis. GA improved the cardiac function and attenuated the inflammatory cell infiltration in vivo. We also found that nuclear factor-kB signaling pathway, which was activated under hypoxia environment, was also suppressed in the GA-treated group.

CONCLUSION

We verified the function and mechanism of GA and provide evidence that GA may play a vital role in ischemic-reperfusion injury, and understanding the precise role of GA will undoubtedly shed new light on the clinical treatment.

The Na,K-ATPase in vascular smooth muscle cells

The Na,K-ATPase is an enzyme essential for ion homeostasis in all cells. Over the last decades, it has been well-established that in addition to the transport of Na⁺/K⁺ over the cell membrane, the Na,K-ATPase acts as a receptor transducing humoral signals intracellularly. It has been suggested that ouabain-like compounds serve as endogenous modulators of this Na,K-ATPase signal transduction. The molecular mechanisms underlying Na,K-ATPase signaling are complicated and suggest the confluence of divergent biological pathways. This review discusses recent updates on the Na,K-ATPase signaling pathways characterized or suggested in vascular smooth muscle cells. The conventional view on this signaling is based on a microdomain structure where the Na,K-ATPase controls the Na,Ca-exchanger activity via modulation of intracellular Na⁺ in the spatially restricted submembrane space. This, in turn, affects intracellular Ca²⁺ and Ca²⁺ load in the sarcoplasmic reticulum leading to modulation of contractility as well as gene expression. An ion-transport-independent signal transduction from the Na,K-ATPase is based on molecular interactions. This was primarily characterized in other cell types but recently also demonstrated in vascular smooth muscles. The downstream signaling from the Na,K-ATPase includes Src and phosphatidylinositol-4,5-bisphosphate 3 kinase signaling pathways and generation of reactive oxygen species. Moreover, in vascular smooth muscle cells the interaction between the Na,K-ATPase and proteins responsible for Ca²⁺ homeostasis, e.g., phospholipase C and inositol triphosphate receptors, contributes to an integration of the signaling pathways. Recent update on the Na,K-ATPase dependent intracellular signaling and the significance for physiological functions and pathophysiological changes are discussed in this review.