Verapamil Inhibits Mitochondria-Induced Reactive Oxygen Species and Dependent Apoptosis Pathways in Cerebral Transient Global Ischemia/Reperfusion

Verapamil and tangeretin enhances the M1 macrophages to M2 type in lipopolysaccharide-treated mice and inhibits the P-glycoprotein expression by downregulating STAT1/STAT3 and upregulating SOCS3

LPS induced sepsis is a complex process involving various immune cells and signaling molecules. Dysregulation of macrophage polarization and ROS production contributed to the pathogenesis of sepsis. PGP is a transmembrane transporter responsible for the efflux of a number of drugs and also expressed in murine macrophages. Natural products have been shown to decrease inflammation and expression of efflux transporters. However, no treatment is currently available to treat LPS induced sepsis. Verapamil and Tangeretin also reported to attenuate lipopolysaccharide-induced inflammation. However, the effects of verapamil or tangeretin on lipopolysaccharide (LPS)-induced sepsis and its detailed anti-inflammatory mechanism have not been reported. Here, we have determined that verapamil and tangeretin protects against LPS-induced sepsis by suppressing M1 macrophages populations and also through the inhibition of P-glycoprotein expression via downregulating STAT1/STAT3 and upregulating SOCS3 expression in macrophages. An hour before LPS (10 mg/kg) was administered; mice were given intraperitoneal injections of either verapamil (5 mg/kg) or tangeretin (5 mg/kg). The peritoneal macrophages from different experimental groups of mice were isolated. Hepatic, pulmonary and splenic morphometric analyses revealed that verapamil and tangeretin decreased the infiltration of neutrophils into the tissues. Verapamil and tangeritin also enhanced the activity of SOD, CAT, GRX and GSH level in all the tissues tested. verapamil or tangeretin pre-treated mice shifted M1 macrophages to M2 type possibly through the inhibition of P-glycoprotein expression via downregulating STAT1/STAT3 and upregulating SOCS3 expression. Hence, both these drugs have shown protective effects in sepsis via suppressing iNOS, COX-2, oxidative stress and NF-κB signaling in macrophages. Therefore, in our study we can summarize that mice were treated with either Vera or Tan before LPS administration cause an elevated IL-10 by the macrophages which enhances the SOCS3 expression, and thereby able to limits STAT1/STAT3 inter-conversion in the macrophages. As a result, NF-κB activity is also getting down regulated and ultimately mitigating the adverse effect of inflammation caused by LPS in resident macrophages. Whether verapamil or tangeretin offers such protection possibly through the inhibition of P-glycoprotein expression in macrophages needs clarification with the bio availability of these drugs under PGP inhibited conditions is a limitation of this study.

Targeted Energy Metabolomics Combined with Spatial Metabolomics Study on the Efficacy of Guhong Injection Against Cerebral Ischemia Reperfusion

Optimizing the metabolic phenotype to improve cerebral function is critical for treatment of cerebral ischemia-reperfusion (I/R) injury. Guhong injection (GHI), which comprised safflower extract and aceglutamide, is widely prescribed in Chinese medicine for the treatment of cerebrovascular diseases. In this study, a combination of LC-QQQ-MS and MALDI-MSI were utilized to explore tissue-specific metabolic alterations in the brain of I/R, as well as to evaluate the therapeutic effect of GHI. Pharmacological evaluation demonstrated that GHI can significantly improve infarction rate, neurological deficit, cerebral blood flow, and neuronal damage in I/R rats. Based on LC-QQQ-MS, 23 energy metabolites were found to be significantly altered in the I/R group compared to the sham group (P < 0.05). After GHI treatment, 12 metabolites, including G6P, TPP, NAD, citrate, succinate, malate, ATP, GTP, GDP, ADP, NADP, and FMN showed a significant tendency of returning to baseline values (P < 0.05). Based on MALDI-MSI, 4 metabolites in glycolysis and TCA, 4 metabolites in nucleic acid metabolism, 4 amino acid metabolites, and 6 metabolites were discovered and compared between the different groups in the four special regions of cortex, hippocampus, hypothalamus, and striatum. Parts of these were found to have significant changes after I/R in the special brain region, and were regulated by GHI. The study provides comprehensive and detailed information for specific metabolic reprogramming of brain tissue in rats with I/R, and the therapeutic effect of GHI. Schema describing the discovery strategies of integrated LC-MS and MALDI-MSI to identify cerebral ischemia reperfusion metabolic reprogramming and GHI therapeutic effects.

The Combined Treatment of Curcumin with Verapamil Ameliorates the Cardiovascular Pathology in a Williams-Beuren Syndrome Mouse Model

Williams-Beuren syndrome (WBS) is a rare disorder caused by a recurrent microdeletion with hallmarks of cardiovascular manifestations, mainly supra-valvular aortic stenosis (SVAS). Unfortunately, there is currently no efficient treatment. We investigated the effect of chronic oral treatment with curcumin and verapamil on the cardiovascular phenotype of a murine model of WBS harbouring a similar deletion, CD (complete deletion) mice. We analysed systolic blood pressure in vivo and the histopathology of the ascending aorta and the left ventricular myocardium to determine the effects of treatments and their underlying mechanism. Molecular analysis showed significantly upregulated xanthine oxidoreductase (XOR) expression in the aorta and left ventricular myocardium of CD mice. This overexpression is concomitant with increased levels of nitrated proteins as a result of byproduct-mediated oxidative stress damage, indicating that XOR-generated oxidative stress impacts the pathophysiology of cardiovascular manifestations in WBS. Only the combined therapy of curcumin and verapamil resulted in a significant improvement of cardiovascular parameters via activation of the nuclear factor erythroid 2 (NRF2) and reduction of XOR and nitrated protein levels. Our data suggested that the inhibition of XOR and oxidative stress damage could help prevent the severe cardiovascular injuries of this disorder.

Combination of puerarin and tanshinone IIA alleviates ischaemic stroke injury in rats via activating the Nrf2/ARE signalling pathway

CONTEXT

Puerarin (Pue) and tanshinone IIA (Tan IIA) are often used in combination in the treatment of cerebrovascular diseases.

OBJECTIVE

To investigate the neuroprotective effect and synergic mechanism of Pue-Tan IIA on the treatment of ischaemic stroke (IS).

MATERIALS AND METHODS

IS was induced in rats by middle cerebral artery occlusion (MCAO). Rats were intraperitoneally injected with Pue (36 mg/kg), Tan IIA (7.2 mg/kg), or Pue-Tan IIA (36 and 7.2 mg/kg) for five times [30 min before ischaemia, immediately after reperfusion (0 h), 24, 48, and 72 h after reperfusion]. After administration, neurological function assessment and histological changes in the brain were performed. S-100β and NSE levels were measured to determine the severity of brain injury. Oxidative stress parameters and inflammatory mediators were measured. The proteins involved in Nrf2/ARE signalling pathway were determined by qRT-PCR and western blot.

RESULTS

After administration, the neurological function scores, infarct volume, S-100β, and NSE levels were significantly reduced in MCAO rats, especially with Pue-Tan IIA treatment (p < 0.05). All treatments increased T-AOC, CAT, SOD, and GSH activities and reduced GSSG activity and MDA, TNF-α, IL-6, ICAM-1, and COX-2 levels in MCAO rats. Pue-Tan IIA significantly increased Nrf2 expression in the nucleus (1.81-fold) and decreased its expression in the cytoplasm (0.60-fold). Pue-Tan IIA significantly increased the expressions of HO-1 (1.87-fold) and NQO1 (1.76-fold) and decreased Keap1 expression (0.39-fold).

DISCUSSION AND CONCLUSIONS

The combination of Pue and Tan IIA could alleviate ischaemic brain injury by activating Nrf2/ARE signalling pathway, providing an experimental basis for clinical applications.

Verapamil inhibits TXNIP-NLRP3 inflammasome activation and preserves functional recovery after intracerebral hemorrhage in mice

Intracerebral hemorrhage (ICH) is the second most common type of stroke with no satisfactory treatment. Recent studies from our group and others indicated a potential positive effect of verapamil, a commonly prescribed calcium channel blocker, with thioredoxin-interacting protein (TXNIP) inhibitor properties, in ischemic stroke and cognitive disorders. It is unclear whether there would be a beneficial effect of verapamil administration in ICH. Therefore, this study was designed to determine the neuroprotective effects of verapamil in a murine ICH model. ICH was induced by stereotactic injection of collagenase type VII (0.075 U) into the right striatum of adult male C57BL/6 mice. Verapamil (0.15 mg/kg) or saline was administered intravenously at 1 h post-ICH followed by oral (1 mg/kg/d) administration in drinking water for 28 days. Motor and cognitive function were assessed using established tests for motor coordination, spatial learning, short- and long-term memory. A subset of animals was sacrificed at 72 h after ICH for molecular analysis. Verapamil treatment reduced expression of TXNIP and NOD-like receptor pyrin domain-containing-3 inflammasome activation in the perihematomal area. These protective effects of verapamil were associated with decreased proinflammatory mediators, microglial activation, and blood-brain barrier permeability markers and paralleled less phosphorylated nuclear factor kappa B level. Our findings also demonstrate that long-term low-dose verapamil effectively attenuated motor and cognitive impairments. Taken together, these data indicate that verapamil has therapeutic potential in improving acute motor function after ICH. Further investigations are needed to confirm whether verapamil treatment could be a promising candidate for clinical trials.

Receptor-Interacting Protein 3/Calmodulin-Dependent Kinase II/Proline-Rich Tyrosine Kinase 2 Pathway is Involved in Programmed Cell Death in a Mouse Model of Brain Ischaemic Stroke

Neuronal necroptosis and apoptosis are the most important pathways for programmed cell death after brain ischaemic stroke. Although apoptosis signalling pathways have been extensively studied, molecular mechanisms underlying necroptosis remain unclear. In this study, we found that receptor-interacting protein 3 (RIP3) deficiency reduced cerebral infarction volume, neurological deficits, and neuronal ultrastructural damage in a mouse model of brain ischaemic stroke by inhibiting programmed cell death. RIP3 deficiency inhibited the activation of both calmodulin-dependent kinase II (CaMKII) and proline-rich tyrosine kinase 2 (Pyk2) cascade, decreased the expression of classic necroptotic and apoptotic proteins, and ultimately decreased neuronal necroptosis and apoptosis. We further confirmed that RIP3 deficiency inhibited the decrease of mitochondrial membrane potential, the increase of calcium influx and reactive oxygen species (ROS) production. In addition, compared with WT primary cortical neurons, the decreased expression of CaMKII and Pyk2 was further verified in a Ripk3^-/- primary cortical neurons underlying oxygen and glucose deprivation/reoxygenation (OGD/R) model. In conclusion, we first identified that the RIP3/CaMKII/Pyk2 pathway is involved in programmed cell death after brain ischaemic stroke, which suggests it is a promising therapeutic target in ischaemia-induced neuronal injury.

Chronotherapeutic neuroprotective effect of verapamil against lipopolysaccharide-induced neuroinflammation in mice through modulation of calcium-dependent genes

Background

Neuroinflammation is a major mechanism in neurodegenerative diseases such as Alzheimer’s disease (AD), which is a major healthcare problem. Notwithstanding of ample researches figured out possible molecular mechanisms underlying the pathophysiology of AD, there is no definitive therapeutics that aid in neuroprotection. Therefore, searching for new agents and potential targets is a critical demand. We aimed to investigate the neuroprotective effect of verapamil (VRP) against lipopolysaccharide (LPS)-induced neuroinflammation in mice and whether the time of VRP administration could affect its efficacy.

Methods

Forty male albino mice were used and were divided into normal control, LPS only, morning VRP, and evening VRP. Y-maze and pole climbing test were performed as behavioral tests. Hematoxylin and eosin together with Bielschowsky silver staining were done to visualize neuroinflammation and phosphorylated tau protein (pTAU); respectively. Additionally, the state of mitochondria, the levels of microglia-activation markers, inflammatory cytokines, intracellular Ca2+, pTAU, and Ca2+-dependent genes involving Ca2+/ calmodulin dependent kinase II (CAMKII) isoforms, protein kinase A (PKA), cAMP response element-binding protein (CREB), and brain-derived neurotrophic factor (BDNF), with the level of VRP in the brain tissue were measured.

Results

LPS successfully induced neuroinflammation and hyperphosphorylation of tau protein, which was indicated by elevated levels of microglia markers, inflammatory cytokines, and intracellular Ca2+ with compromised mitochondria and downregulated CAMKII isoforms, PKA, CREB and BDNF. Pretreatment with VRP showed significant enhancement in the architecture of the brain and in the behavioral tests as indicated by the measured parameters. Moreover, morning VRP exhibited better neuroprotective profile compared to the evening therapy.

Conclusions

VRP highlighted a multilevel of neuroprotection through anti-inflammatory activity, Ca2+ blockage, and regulation of Ca2+-dependent genes. Furthermore, chronotherapy of VRP administration should be consider to achieve best therapeutic efficacy.

Graphical Abstract

Apoptosis Effects of Oxalis corniculata L. Extract on Human MCF-7 Breast Cancer Cell Line:

Background: Recently, the non-toxic properties of natural plant products have gained more focus as anticancer agents. Therefore, this study aimed to assess the apoptosis effects of the ethanolic extract of Oxalis corniculata on the MCF-7 breast cancer cell line.Materials and Methods: In this experimental study, aerial parts of O. corniculata were collected in Lahijan city (Iran), and after confirmation, they were dried and extracted with ethanol for 24 h. Then, the total phenolic and flavonoid contents of the extract were measured. The 2,2-diphenyl-1-picrylhydrazyl radical scavenging assay was used to measure the antioxidant properties of the extract. Selected cell lines (MCF-7 and human dermal fibroblast) were cultured in 6-wells dishes (1×10⁶ cells/well). After 72 h of treating the extract, cytotoxicity was assessed using 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyl-2H-tetrazolium bromide (MTT) assay. The expression of apoptotic genes (such as p53, bcl-2, bax, and CD95) was studied by real-time polymerase chain reaction (PCR). Results: The extract's total phenolic content was 31.30±02 μg of gallic acid equivalents/mg of dry extract, and the total flavonoid content was 49.61±04 μg of quercetin as equivalents/mg of extract. The antioxidant activity ofO. corniculata was measured at the dose of 619.2 μg/μl, indicating that it decreases cancer cell viability and enhances apoptosis. Within the half maximal inhibitory concentrations, real-time PCR revealed substantial increases in p53 (P<0.001), CD95 (P<0.05), and bcl-2 expression (P<0.05) in MCF-7 cells treated with O. corniculata. Conclusion: This study suggests that O. corniculata may cause apoptosis by oxidative stress in cancer cells.[GMJ.2022;11:e2484].

Mitochondrial Effects of Common Cardiovascular Medications: The Good, the Bad and the Mixed

Mitochondria are central organelles in the homeostasis of the cardiovascular system via the integration of several physiological processes, such as ATP generation via oxidative phosphorylation, synthesis/exchange of metabolites, calcium sequestration, reactive oxygen species (ROS) production/buffering and control of cellular survival/death. Mitochondrial impairment has been widely recognized as a central pathomechanism of almost all cardiovascular diseases, rendering these organelles important therapeutic targets. Mitochondrial dysfunction has been reported to occur in the setting of drug-induced toxicity in several tissues and organs, including the heart. Members of the drug classes currently used in the therapeutics of cardiovascular pathologies have been reported to both support and undermine mitochondrial function. For the latter case, mitochondrial toxicity is the consequence of drug interference (direct or off-target effects) with mitochondrial respiration/energy conversion, DNA replication, ROS production and detoxification, cell death signaling and mitochondrial dynamics. The present narrative review aims to summarize the beneficial and deleterious mitochondrial effects of common cardiovascular medications as described in various experimental models and identify those for which evidence for both types of effects is available in the literature.

Neurotoxic effects of environmental contaminants-measurements, mechanistic insight, and environmental relevance

Pollution is a significant and growing concern for any population regardless of age because these environmental contaminants exhibit different neurodegenerative effects on persons of different ages. These environmental contaminants are the products of human welfare projects like industry, automobile exhaust, clinical and research laboratory extrudes, and agricultural chemicals. These contaminants are found in various forms in environmental matrices like nanoparticles, particulate matter, lipophilic vaporized toxicants, and ultrafine particulate matter. Because of their small size, they can easily cross blood-brain barriers or use different cellular mechanisms for assistance. Other than this, these contaminants cause an innate immune response in different cells of the central nervous system and cause neurotoxicity. Considering the above critiques and current needs, this review summarizes different protective strategies based on bioactive compounds present in plants. Various bioactive compounds from medicinal plants with neuroprotective capacities are discussed with relevant examples. Many in vitro studies on clinical trials have shown promising outcomes using plant-based bioactive compounds against neurological disorders.

Involvement of Multidrug Resistance Modulators in the Regulation of the Mitochondrial Permeability Transition Pore

The permeability transition pore in mitochondria (MPTP) and the ATP-binding cassette transporters (АВС transporters) in cell membranes provide the efflux of low-molecular compounds across mitochondrial and cell membranes, respectively. The inhibition of ABC transporters, especially of those related to multi drug resistance (MDR) proteins, is an actively explored approach to enhance intracellular drug accumulation and increase thereby the efficiency of anticancer therapy. Although there is evidence showing the simultaneous effect of some inhibitors on both MDR-related proteins and mitochondrial functions, their influence on MPTP has not been previously studied. We examined the participation of verapamil and quinidine, classified now as the first generation of MDR modulators, and avermectin, which has recently been actively studied as an MDR inhibitor, in the regulation of the MPTP opening. In experiments on rat liver mitochondria, we found that quinidine lowered and verapamil increased the threshold concentrations of calcium ions required for MPTP opening, and that they both decreased the rate of calcium-induced swelling of mitochondria. These effects may be associated with the positive charge of the drugs and their aliphatic properties. Avermectin not only decreased the threshold concentration of calcium ions, but also by itself induced the opening of MPTP and the mitochondrial swelling inhibited by ADP and activated by carboxyatractyloside, the substrate and inhibitor of adenine nucleotide translocase (ANT), which suggests the involvement of ANT in the process. Thus, these data indicate an additional opportunity to evaluate the effectiveness of MDR modulators in the context of their influence on the mitochondrial-dependent apoptosis.

Verapamil attenuates oxidative stress and inflammatory responses in cigarette smoke (CS)-induced murine models of acute lung injury and CSE-stimulated RAW 264.7 macrophages via inhibiting the NF-κB pathway

Acute lung injury (ALI) and acute respiratory distress syndrome (ARDS), severe form of ALI, are characterized by overwhelming of lung inflammation, and no treatment is currently available to treat ALI/ARDS. Cigarette smoke (CS) is one of the prime causes to induce ALI/ARDS via oxidative stress. Despite extensive research, no appropriate therapy is currently available to treat ALI/ARDS. Hence, new potential approaches are needed to treat ALI/ARDS. Consequently, this project was designed to explore the protective effects of verapamil against CS-induced ALI by in vivo and in vitro method. In vivo data obtained from respiratory mechanics, pulmonary morphometric analyses and lung histopathology revealed that verapamil dose-dependently and strikingly decreased the lung weight coefficient, attenuated the albumin exudation into lungs, minimized the infiltration of macrophages and neutrophils into lungs, reduced the pro-inflammatory cytokines (tumour necrosis factor-α (TNF-α), interleukin-6 (IL-6) and keratinocyte chemoattractant (KC)) production, and improved the hypoxemia and lung histopathological changes. Similarly, verapamil also reduced the production of TNF-α, IL-6 and KC from cigarette smoke extract (CSE)-stimulated RAW 264.7 macrophage. Importantly, verapamil dose-dependently and remarkably suppressed the CS-induced oxidative stress via not only reducing the myeloperoxidase (MPO) activity of lungs, total oxidative stress (TOS) and malondialdehyde (MDA) content in the lungs and supernatant of RAW 264.7 macrophage but also improving total antioxidant capacity (TAC) and superoxide dismutase (SOD) production. Finally, verapamil strikingly decreased the NF-κB expression both in in vivo and in vitro models. Hence, verapamil has positive therapeutic effects against CS-induced ALI via suppressing uncontrolled inflammatory response, oxidative stress and NF-κB p65 signaling.

miR-92b-3p Exerts Neuroprotective Effects on Ischemia/Reperfusion-Induced Cerebral Injury via Targeting NOX4 in a Rat Model

The necessity to increase the efficiency of organ preservation has pushed researchers to consider the mechanisms to minimize cerebral ischemia/reperfusion (I/R) injury. Hence, we evaluated the role of the miR-92b-3p/NOX4 pathway in cerebral I/R injury. A cerebral I/R injury model was established by blocking the left middle cerebral artery for 2 h and reperfusion for 24 h, and a hypoxia/reoxygenation (H/R) model was established. Thereafter, cerebral I/R increased obvious neurobiological function and brain injury (such as cerebral infarction, apoptosis, and cell morphology changes). In addition, we noted a significant decrease in the expression of miR-92b-3p, as well as increases in apoptosis and oxidative stress and an increase in NOX4. Furthermore, overexpression of miR-92b-3p blocked the inhibitory effect of miR-92b-3p on the expression of NOX4 and the accumulation of oxygen-free radicals. Bioinformatics analysis found that NOX4 may be the target gene regulated by miR-92b-3p. In conclusion, the involvement of the miR-92b-3p/NOX4 pathway ameliorated cerebral I/R injury through the prevention of apoptosis and oxidative stress. The miR-92b-3p/NOX4 pathway could be considered a potential therapeutic target to alleviate cerebral I/R injury.

Verapamil Alleviates Myocardial Ischemia/Reperfusion Injury by Attenuating Oxidative Stress via Activation of SIRT1

Myocardial ischemia/reperfusion (I/R) injury is a potential complication of ischemic heart disease after recanalization. One of the primary reasons for I/R injury is the excessive accumulation of reactive oxygen species (ROS) in cardiomyocytes. Verapamil, a classic calcium channel blocker, has the potential to mitigate I/R-evoked oxidative stress. However, the underlying mechanisms have not been fully elucidated. SIRT1 is an essential regulator of I/R and offers resistance to oxidative stress arising from I/R. It is still inconclusive if verapamil can reduce myocardial I/R-triggered oxidative damage through modulating SIRT1 antioxidant signaling. To verify our hypothesis, the H9c2 cardiomyocytes and the mice were treated with verapamil and then exposed to hypoxia/reoxygenation (H/R) or I/R in the presence or absence of the SIRT1 inhibitor EX527. As expected, verapamil stimulated SIRT1 antioxidant signaling evidenced by upregulation of SIRT1, FoxO1, SOD2 expressions and downregulation of Ac-FoxO1 expression in vitro and in vivo. In addition, verapamil remarkably suppressed H/R and I/R-induced oxidative stress proven by declined ROS level and MDA content. The cardioprotective actions of verapamil via SIRT1 were further confirmed in the experiments with the presence of the specific SIRT1 inhibitor EX527. We demonstrated that verapamil alleviated myocardial I/R-evoked oxidative stress partially via activation of SIRT1 antioxidant signaling. Subsequently, verapamil protected against cardiac dysfunction and myocardial infarction accompanied by oxidative stress.

Global Cerebral Ischemia in Male Long Evans Rats Impairs Dopaminergic/ΔFosB Signalling in the Mesocorticolimbic Pathway Without Altering Delay Discounting Rates

Global cerebral ischemia (GCI) in rats has been shown to promote exploration of anxiogenic zones of the Elevated-Plus Maze (EPM) and Open Field Test (OFT). This study investigated changes in impulsive choice and/or defensive responses as possible contributors of heightened anxiogenic exploration observed after ischemia. Impulsivity was assessed using delay discounting (DD) paradigms, while the Predator Odour Test (PO) served to assess changes in defensive responses towards a naturally aversive stimulus. Male Long Evans rats underwent 9 days of autoshaping training and 24 days of DD training prior to GCI or sham surgery (n = 9/group). Post-surgery, rats completed the OFT, EPM, and PO, followed by 6 days of DD sessions. Blood droplets served to evaluate corticosterone secretion associated with PO exposure. With impulsivity being regulated through mesocorticolimbic monoaminergic pathways, we also characterised post-ischemic changes in the expression of dopamine D₂ receptors (DRD₂), dopamine transporters (DAT), and 1FosB in the basolateral amygdala (BLA), nucleus accumbens core (NAcC) and shell (NAcS), and ventromedial prefrontal cortex (vmPFC) using immunohistofluorescence. Our findings revealed no impact of GCI on delay discounting rates, while PO approach behaviours were minimally affected. Nonetheless, GCI significantly reduced DRD₂ and ΔFosB-ir in the NAcS and NAcC, respectively, while DAT-ir was diminished in both NAc subregions. Collectively, our findings refine the understanding of cognitive-behavioural and biochemical responses following stroke or cardiac arrest. They support significant alterations to the dopaminergic mesocorticolimbic pathway after ischemia, which are not associated with altered impulsive choice in a DD task but may influence locomotor exploration of the OFT and EPM.

Relevance of mitochondrial oxidative stress to arrhythmias: Innovative concepts to target treatments

Cardiac arrhythmia occurs frequently worldwide, and in severe cases can be fatal. Mitochondria are the power plants of cardiomyocytes. In recent studies, mitochondria under certain stimuli produced excessive reactive oxygen species (ROS), which affect the normal function of cardiomyocytes through ion channels and related proteins. Mitochondrial oxidative stress (MOS) plays a key role in diseases with multifactorial etiopathogenesis, such as arrhythmia; MOS can lead to arrhythmias such as atrial fibrillation and ventricular tachycardia. This review discusses the mechanisms of arrhythmias caused by MOS, particularly of ROS produced by mitochondria. MOS can cause arrhythmias by affecting the activities of Ca²⁺-related proteins, the mitochondrial permeability transition pore protein, connexin 43, hyperpolarization-activated cyclic nucleotide-gated potassium channel 4, and ion channels. Based on these mechanisms, we discuss possible new treatments for arrhythmia. Targeted treatments focusing on mitochondria may reduce the progression of arrhythmias, as well as the occurrence of severe arrhythmias, and may be effective for personalized disease prevention.

Verapamil ameliorates proximal tubular epithelial cells apoptosis and fibrosis in diabetic kidney

Diabetic kidney disease (DKD) is a severe complication of diabetes mellitus for which there is still no effective treatment. We previously showed that upregulation of thioredoxin-interacting protein (TXNIP), an endogenous inhibitor of thioredoxin (TRX), accelerates the progression of DKD. In this study, we hypothesized whether verapamil, a calcium channel blocker and an established TXNIP inhibitor, might exert a renal-protective effect on DKD by regulating TXNIP expression. Herein, a systemic pharmacological network study was performed and multiple molecules and pathways targeted by verapamil on DKD were characterized. Furthermore, diabetic mice were induced by streptozotocin (STZ), and verapamil (100 mg/kg/day) or saline was intraperitoneally injected into the mice. After 16 weeks, mice were analyzed for blood glucose, blood pressure, and functional parameters followed by sacrifice and evaluation of renal tubular injury, alterations in TXNIP, apoptosis and fibrosis markers. Additionally, the effects of treatment with verapamil (50 μM, 100 μM, 150 μM) under high glucose conditions on the expression of TXNIP and signaling pathway components in proximal tubular epithelial cells (PTEC, HK-2 cells) were explored. According to these findings, we conclude that verapamil might serve as a potential agent for the prevention and treatment of DKD.

Irisin Rescues Blood-Brain Barrier Permeability following Traumatic Brain Injury and Contributes to the Neuroprotection of Exercise in Traumatic Brain Injury

Traumatic brain injury (TBI) has a high incidence, mortality, and morbidity all over the world. One important reason for its poor clinical prognosis is brain edema caused by blood-brain barrier (BBB) dysfunction after TBI. The mechanism may be related to the disorder of mitochondrial morphology and function of neurons in damaged brain tissue, the decrease of uncoupling protein 2 (UCP2) activity, and the increase of inflammatory reaction and oxidative stress. In this study, we aimed to investigate the effects of exogenous irisin on BBB dysfunction after TBI and its role in the neuroprotective effects of endurance exercise (EE) in mice. The concentrations of irisin in cerebrospinal fluid (CSF) and plasma of patients with mild to severe TBI were measured by ELISA. Then, male C57BL/6J mice and UCP2 knockout mice with C57BL/6J background were used to establish the TBI model. The BBB structure and permeability were examined by transmission electron microscopy and Evans blue extravasation, respectively. The protein expressions of irisin, occludin, claudin-5, zonula occludens-1 (ZO-1), nuclear factor E2-related factor 2(Nrf2), quinine oxidoreductase (NQO-1), hemeoxygenase-1 (HO-1), cytochrome C (Cyt-C), cytochrome C oxidase (COX IV), BCL2-associated X protein (Bax), cleaved caspase-3, and UCP2 were detected by western blot. The production of reactive oxygen species (ROS) was evaluated by the dihydroethidium (DHE) staining. The levels of inflammatory factors were detected by ELISA. In this study, we found that the CSF irisin levels were positively correlated with the severity of disease in patients with TBI and both EE and exogenous irisin could reduce BBB damage in a mouse model of TBI. In addition, we used UCP2-/- mice and further found that irisin could improve the dysfunction of BBB after TBI by promoting the expression of UCP2 on the mitochondrial membrane of neurons, reducing the damage of mitochondrial structure and function, thus alleviating the inflammatory response and oxidative stress. In conclusion, the results of this study suggested that irisin might alleviate brain edema after TBI by promoting the expression of UCP2 on the mitochondrial membrane of neurons and contribute to the neuroprotection of EE against TBI.

Mitochondrial Quality Control in Cerebral Ischemia-Reperfusion Injury

Ischemic stroke is one of the leading causes of death and also a major cause of adult disability worldwide. Revascularization via reperfusion therapy is currently a standard clinical procedure for patients with ischemic stroke. Although the restoration of blood flow (reperfusion) is critical for the salvage of ischemic tissue, reperfusion can also, paradoxically, exacerbate neuronal damage through a series of cellular alterations. Among the various theories postulated for ischemia/reperfusion (I/R) injury, including the burst generation of reactive oxygen species (ROS), activation of autophagy, and release of apoptotic factors, mitochondrial dysfunction has been proposed to play an essential role in mediating these pathophysiological processes. Therefore, strict regulation of the quality and quantity of mitochondria via mitochondrial quality control is of great importance to avoid the pathological effects of impaired mitochondria on neurons. Furthermore, timely elimination of dysfunctional mitochondria via mitophagy is also crucial to maintain a healthy mitochondrial network, whereas intensive or excessive mitophagy could exacerbate cerebral I/R injury. This review will provide a comprehensive overview of the effect of mitochondrial quality control on cerebral I/R injury and introduce recent advances in the understanding of the possible signaling pathways of mitophagy and potential factors responsible for the double-edged roles of mitophagy in the pathological processes of cerebral I/R injury.

Melatonin protects against focal cerebral ischemia-reperfusion injury in diabetic mice by ameliorating mitochondrial impairments: involvement of the Akt-SIRT3-SOD2 signaling pathway

Diabetic patients are more vulnerable to cerebral ischemia-reperfusion (CIR) injury and have a worse prognosis and higher mortality after ischemic stroke than non-diabetic counterparts. Melatonin can exert neuroprotective effects against CIR injury in nondiabetic animal models. However, its effects on diabetic CIR injury and the underlying mechanisms remain unclarified. Herein, we found that melatonin administration improved neurological deficit, cerebral infarct volume, brain edema, and cell viability, reduced mitochondrial swelling, reactive oxygen species generation, and cytoplasmic cytochrome C release, and increased mitochondrial antioxidant enzymes activities, adenosine triphosphate production, and mitochondrial membrane potential in both streptozotocin-induced diabetic mice and high glucose-treated HT22 cells. Importantly, melatonin also activated protein kinase B (Akt) and sirtuin 3 (SIRT3)/superoxide dismutase 2 (SOD2) signaling and upregulated mitochondrial biogenesis-related transcription factors. However, these effects were largely attenuated by LY294002 (a specific Akt signaling blocker) administration. Additionally, 3-TYP (a selective SIRT3 inhibitor) and SIRT3 siRNA inhibited the above protective effects of melatonin as well as the upregulation of SIRT3 and the decrease of SOD2 acetylation but did not affect the p-Akt/Akt ratio. Overall, we demonstrate that melatonin can alleviate CIR injury in diabetic mice by activating Akt-SIRT3-SOD2 signaling and subsequently improving mitochondrial damage.

Hydromorphone Protects against CO2 Pneumoperitoneum-Induced Lung Injury via Heme Oxygenase-1-Regulated Mitochondrial Dynamics

Various pharmacological agents and protective methods have been shown to reverse pneumoperitoneum-related lung injury, but identifying the best strategy is challenging. Herein, we employed lung tissues and blood samples from C57BL/6 mice with pneumoperitoneum-induced lung injury and blood samples from patients who received laparoscopic gynecological surgery to investigate the therapeutic role of hydromorphone in pneumoperitoneum-induced lung injury along with the underlying mechanism. We found that pretreatment with hydromorphone alleviated lung injury in mice that underwent CO₂ insufflation, decreased the levels of myeloperoxidase (MPO), total oxidant status (TOS), and oxidative stress index (OSI), and increased total antioxidant status (TAS). In addition, after pretreatment with hydromorphone, upregulated HO-1 protein expression, reduced mitochondrial DNA content, and improved mitochondrial morphology and dynamics were observed in mice subjected to pneumoperitoneum. Immunohistochemical staining also verified that hydromorphone could increase the expression of HO-1 in lung tissues in mice subjected to CO₂ pneumoperitoneum. Notably, in mice treated with HO-1-siRNA, the protective effects of hydromorphone against pneumoperitoneum-induced lung injury were abolished, and hydromorphone did not have additional protective effects on mitochondria. Additionally, in clinical patients who received laparoscopic gynecological surgery, pretreatment with hydromorphone resulted in lower serum levels of club cell secretory protein-16 (CC-16) and intercellular adhesion molecule-1 (ICAM-1), a lower prooxidant-antioxidant balance (PAB), and higher heme oxygenase-1 (HO-1) activity than morphine pretreatment. Collectively, our results suggest that hydromorphone protects against CO₂ pneumoperitoneum-induced lung injury via HO-1-regulated mitochondrial dynamics and may be a promising strategy to treat CO₂ pneumoperitoneum-induced lung injury.

Costunolide attenuates oxygen‑glucose deprivation/reperfusion‑induced mitochondrial‑mediated apoptosis in PC12 cells

The present study investigated the effect of costunolide (CT), a compound extracted from Aucklandia lappa Decne, to attenuate oxygen-glucose deprivation/reperfusion (OGD/R)-induced mitochondrial-mediated apoptosis in PC12 cells. The present study used molecular docking technology to detect the binding of CT with mitochondrial apoptotic protein targets. A model of oxygen-glucose deprivation for 2 h and reperfusion for 24 h in PC12 cells was used to mimic cerebral ischemic injury. Cell viability and damage were measured using the Cell Counting kit-8 and lactate dehydrogenase (LDH) cytotoxicity assay kits. Cellular apoptosis was analyzed using flow cytometry. A fluorescence microscope determined intracellular [Ca²⁺] and mitochondrial membrane potential. Furthermore, immunofluorescence and Western blot analyses were used to detect the expression of apoptosis-associated proteins. CT contains binding sites with Caspase-3, Caspase-9 and Caspase-7. CT markedly enhanced cell viability, inhibited LDH leakage, increased intracellular [Ca²⁺], stabilized the mitochondrial membrane potential, increased the expression of Bcl-2 and inhibited the expression of Apaf-1, Bax, cleaved-caspase-7, cleaved-caspase-9 and cleaved-caspase-3. CT may markedly protect PC12 cells from damage caused by OGD/R, and its mechanism is associated with blocking the calcium channel and inhibiting mitochondrial-mediated apoptosis.