Inhibition Of Calcium Overload Research Articles

Progress of researches on mechanisms of acupuncture underlying improvement of cerebral ischemia-reperfusion injury by regulating calcium overload.

Ischemic stroke is currently the most common type of stroke, and the key pathological link is cerebral ischemia-reperfusion injury (CIRI), while the key factor leading to apoptosis and necrosis of ischemic nerve cells is calcium overload. Current studies have confirmed that acupuncture therapy has a good modulating effect on calcium homeostasis and can reduce cerebral ischemia-reperfusion induced damage of neuronal cells by inhibiting calcium overload. After reviewing the relevant literature published in the past 15 years, we find that acupuncture plays a role in regulating the pathological mechanism of calcium overload after CIRI by inhibiting the opening of connexin 43 hemichannels, regulating the intracellular free calcium ion concentration, suppressing the expression of calmodulin, and blocking the function of L-type voltage-gated calcium channels, thereby inhibiting calcium overload, regulating calcium homeostasis and antagonizing neuronal damage resulted from cerebral ischemia-reperfusion, which may provide ideas for future research.

Zishenhuoxue decoction-induced Myocardial protection against Ischemic injury through TMBIM6-VDAC1-mediated regulation of Calcium homeostasis and mitochondrial quality surveillance

BackgroundZishenhuoxue decoction (ZSHX), a Chinese herbal medicine, exhibits myocardial and vascular endothelial protective properties. The intricate regulatory mechanisms underlying myocardial ischemic injury and its association with dysfunctional mitochondrial quality surveillance (MQS) remain elusive. Hypothesis/PurposeTo study the protective effect of ZSHX on ischemic myocardial injury in mice using a TMBIM6 gene-modified animal model and mitochondrial quality control-related experiments. Study designUsing model animals and myocardial infarction surgery-induced ischemic myocardial injury TMBIM6 gene-modified mouse models, the pharmacological activity of ZSHX in inhibiting ischemic myocardial injury and mitochondrial homeostasis disorder in vivo was tested. MethodsOur focal point entailed scrutinizing the impact of ZSHX on ischemic myocardial impairment through the prism of TMBIM6. This endeavor was undertaken utilizing mice characterized by heart-specific TMBIM6 knockout (TMBIM6CKO) and their counterparts, the TMBIM6 transgenic (TMBIM6TG) and VDAC1 transgenic (VDAC1 TG) mice. ResultsZSHX demonstrated dose-dependent effectiveness in mitigating ischemic myocardial injury and enhancing mitochondrial integrity. TMBIM6CKO hindered ZSHX's cardio-therapeutic and mitochondrial protective effects, while ZSHX's benefits persisted in TMBIM6TG mice. TMBIM6CKO also blocked ZSHX's regulation of mitochondrial function in HR-treated cardiomyocytes. Hypoxia disrupted the MQS in cardiomyocytes, including calcium overload, excessive fission, mitophagy issues, and disrupted biosynthesis. ZSHX counteracted these effects, thereby normalizing MQS and inhibiting calcium overload and cardiomyocyte necroptosis. Our results also showed that hypoxia-induced TMBIM6 blockade resulted in the over-activation of VDAC1, a major mitochondrial calcium uptake pathway, while ZSHX could increase the expression of TMBIM6 and inhibit VDAC1-mediated calcium overload and MQS abnormalities. ConclusionsOur findings suggest that ZSHX regulates mitochondrial calcium homeostasis and MQS abnormalities through a TMBIM6-VDAC1 interaction mechanism, which helps to treat ischemic myocardial injury and provides myocardial protection. This study also offers insights for the clinical translation and application of mitochondrial-targeted drugs in cardiomyocytess.

Mechanism of Magnolia Volatile Oil in the Treatment of Acute Pancreatitis Based on GC-MS, Network Pharmacology, and Molecular Docking.

Magnoliae officinalis cortex (MOC) is one of the most frequently used traditional Chinese medicine (TCM) for the treatment of acute pancreatitis (AP). Magnolia volatile oil (MVO) is considered to be one of the main active ingredients in MOC for AP treatment. However, the underlying mechanism of MVO in AP therapy is unknown. An integrated strategy of gas chromatography-mass spectrum (GC-MS), network pharmacology, and molecular docking simulation was employed to predict underlying mechanism of MVO in AP treatment. First, the compounds of MVO were identified by GC-MS, and the targets of the identified characteristic compounds were collected from several databases, as well as AP-related targets. Next, Gene Ontology (GO) and Kyoto Encyclopedia of Genes and Genomes (KEGG) analysis were carried out to obtain the mechanism. Moreover, the binding activity between core therapeutic targets and their corresponding compounds was evaluated by molecular docking simulation. GC-MS results showed a total of 35 compounds that appeared in at least 18 out of 20 chromatograms were considered as characteristic compounds of MVO, and 33 compounds of those were identified. Network analysis demonstrated that 33 compounds regulated 142 AP-related targets. Of those, 8 compounds (α-eudesmol, γ-eudesmol, (-)-terpinen-4-ol, terpineol, hinesol, linalool, borneol, and β-eudesmol) and 8 targets (TNF, IL-1β, PPARγ, PPARα, PTGS2, NCOA1, CNR1, and ESR1) have a close relationship with AP treatment and were recognized as the key active compounds and the core therapeutic targets, respectively. The 142 targets were involved in both inflammation and calcium overload-related biological pathways, such as neuroactive ligand-receptor interaction, estrogen, MAPK, and calcium signaling pathway. Moreover, molecular docking simulation indicated that the 8 core therapeutic targets strongly interacted with their corresponding compounds. In summary, the present study elucidated that the efficacy of MVO in AP treatment might be attributed to anti-inflammation and inhibition of calcium overload through multicomponents and multitargets.

[Regulation of myocardial ischemia reperfusion injury signal pathway by flavonoid monomer].

Acute myocardial infarction seriously endangers the health of people due to its high morbidity and high mortality. Reperfusion strategy is the preferred treatment strategy for acute myocardial infarction. However, reperfusion may lead to additional heart damage, namely myocardial ischemia reperfusion injury(MIRI). Therefore, how to reduce myocardial ischemia reperfusion injury has become one of the urgent problems to be solved in cardiovascular disease. Traditional Chinese medicine(TCM) has the multi-component, multi-channel, and multi-target advantages in the treatment of MIRI, which offers new ideas in this aspect. TCM containing flavonoids has a variety of biological activities and plays a significant role in the treatment of MIRI, which has great research and development application value. TCM containing flavonoids can regulate multiple signaling pathways of MIRI, such as phosphatidylinositol 3 kinase/kinase B(PI3K/Akt) signaling pathway, Janus kinase/signal transducer and activator of transcriptions(JAK/STAT) signaling pathway, adenosine 5'-monophosphate(AMP)-activated protein kinase(AMPK) signaling pathway, mitogen-activated protein kinase(MAPK) signaling pathway, nuclear factor-erythroid 2-related factor 2/antioxidant response element(Nrf2/ARE) signaling pathway, nuclear factor kappa-B(NF-κB) signaling pathway, silent information regulator 1(Sirt1) signaling pathway, and Notch signaling pathway. It reduces MIRI by inhibiting calcium overload, improving energy metabolism, regulating autophagy, and inhibiting ferroptosis and apoptosis. Therefore, a review has been made based on the regulation of relative signaling pathways against MIRI by TCM containing flavonoids, thus providing theoretical support and potential therapeutic strategies for TCM to alleviate MIRI.

Effect of Tetrahedral Framework Nucleic Acids on Neurological Recovery via Ameliorating Apoptosis and Regulating the Activation and Polarization of Astrocytes in Ischemic Stroke

Astrocytes, as the most plentiful subtypes of glial cells, play an essential biphasic function in ischemic stroke (IS). However, although having beneficial effects on stroke via promoting nerve restoration and limiting lesion extension, astrocytes can unavoidably cause exacerbated brain damage due to their participation in the inflammatory response. Therefore, seeking an effective and safe drug/strategy for protecting and regulating astrocytes in stroke is urgent. Here, we employ tetrahedral framework nucleic acid (tFNA) nanomaterials for astrocytes in stroke, considering their excellent biological properties and outstanding biosafety. In vitro, tFNA can inhibit calcium overload and ROS regeneration triggered by oxygen-glucose deprivation/reoxygenation (OGD/R), which provides a protective effect against astrocytic apoptosis. Furthermore, morphological changes such as hyperplasia and hypertrophy of reactive astrocytes are restrained, and the astrocytic polarization from the proinflammatory A1 phenotype to the neuroprotective A2 phenotype is facilitated by tFNA, which further alleviates cerebral infarct volume and facilitates the recovery of neurological function in transient middle cerebral artery occlusion (tMCAo) rat models. Moreover, the TLRs/NF-κB signaling pathway is downregulated by tFNA, which may be the potential mechanism of tFNA for protecting astrocytes in stroke. Collectively, we demonstrate that tFNA can effectively mediate astrocytic apoptosis, activation, and polarization to alleviate brain injury, which represents a potential intervention strategy for IS.

Saprirearine protects H9c2 cardiomyocytes against hypoxia/reoxygenation-induced apoptosis by activating Nrf2.

Myocardial infarction is a major cause of mortality and disability worldwide. Ischemia/reperfusion injury is the key factor that results in the increase in infarct size in pathogenesis. To find a novel therapy for myocardial infarction, we have evaluated saprirearine, a natural diterpenoid, using H9c2 cardiomyocytes injured by hypoxia/reoxygenation and explored the possible mechanisms. The results showed that saprirearine improved cell survival by increasing cell viability and blocking the release of lactate dehydrogenase. Meanwhile, saprirearine was found to attenuate mitochondrial dysfunction by inhibiting calcium overload, collapse of the mitochondrial membrane potential, and opening of the mitochondrial permeability transition pore. And oxidative stress resulting from hypoxia/reoxygenation was ameliorated by saprirearine through the reduction of reactive oxygen species and malondialdehyde as well as activation of superoxide dismutase and catalase. Additionally, saprirearine inactivated cysteinyl aspartate-specific proteinase-3, the up-regulated B-cell lymphoma-2 and down-regulated Bcl-2-associated X protein, to inhibit hypoxia/reoxygenation-induced apoptosis. Further research revealed saprirearine-activated nuclear factor E2-related factor-2 in H9c2 cardiomyocytes, which is closely associated with its protective effects. These findings can provide evidence for the discovery of new therapies targeting myocardial infarction and the application of saprirearine in clinical practice.

Electro-Acupuncture Pretreatment Ameliorates Anesthesia and Surgery-Induced Cognitive Dysfunction Via Inhibiting Mitochondrial Injury and nEuroapoptosis in Aged Rats.

Postoperative cognitive dysfunction (POCD) remains one of the most common complications following anesthesia and surgery (AS) in the elderly population. Calcium-mediated mitochondrial injury has been proved to induce cognitive impairment in a variety of neurologic diseases. In the current study we determined whether electro-acupuncture (EA) pretreatment ameliorated AS-induced POCD in aged rats, as well as the underlying mechanism. Eighty SD rats (18months, male) were randomly assigned into four groups (n = 20): C, C + EA, POCD and EA + POCD. Rats in Group POCD and EA + POCD were subjected to exploratory laparotomy under sevoflurane anesthesia. Rats of Group C + EA and EA + POCD received a 5-day EA stimulation at Hegu, Neiguan and Zusanli acupoints before AS. At 3rd day after AS, open field test along with Morris water maze test were employed to examine the cognitive function of aged rats. Then hippocampal tissues were stripped and hippocampal neuronal amount, expression level of cleaved caspase-9 level, cytochrome c (Cyt C), cleaved caspase-3 level, Bcl-2, Bax, ROS expression level, apoptosis rate, mitochondrial membrane potential (MMP), cytosolic calcium concentration ([Ca2+]c), opening level of mitochondrial permeability transition pore (mPTP) and ultrastructure of hippocampal neurons were detected separately. EA pretreatment inhibited AS-induced cognitive dysfunction. Furthermore, EA pretreatment decreased level of [Ca2+]c, MMP, mPTP, ROS and hippocampal mitochondrial disruption and enhanced neuronal amount. In addition, EA pretreatment notably reduced the AS-induced increased level of cleaved caspase-9, cleaved caspase-3 and expression of Cyt c, Bax/Bcl-2 ratio, as well as neuronal apoptosis rate in aged rats. EA pretreatment ameliorates AS-induced POCD in aged rats, the potential mechanism may be associated with inhibiting calcium overload and ameliorating mitochondrial injury and neuroapoptosis in hippocampal neurons.

Calenduloside E protects against myocardial ischemia-reperfusion injury induced calcium overload by enhancing autophagy and inhibiting L-type Ca2+ channels through BAG3.

Calenduloside E (CE) is a saponin isolated from Aralia elata (Miq) Seem, which has anti-cardiovascular disease effects. This study aims to evaluate the anti-myocardial ischemia-reperfusion injury (MIRI) mechanisms of CE and regulation of BAG3 on calcium overload. We adopted siRNA to interfere with BAG3 expression in H9c2 cardiomyocytes and used adenovirus to interfere with BAG3 expression (Ad-BAG3) in primary neonatal rat cardiomyocytes (PNRCMs) to clarify the role of BAG3 in mitigating MIRI by CE. The results showed that CE reduced calcium overload, and Ad-BAG3 had a significant regulatory effect on L-type Ca2+ channels (LTCC) but no effects on other calcium-related proteins. And BAG3 and LTCC were colocalized in myocardial tissue and BAG3 inhibited LTCC expression. Surprisingly, CE had no regulatory effect on LTCC mRNA, but CE promoted LTCC degradation through the autophagy-lysosomal pathway rather than the ubiquitination-protease pathway. Autophagy inhibitor played a negative regulation of cardiomyocyte contraction rhythm and field potential signals. Ad-BAG3 inhibited autophagy by regulating the expression of autophagy-related proteins and autophagy agonist treatment suppressed calcium overload. Therefore, CE promoted autophagy through BAG3, thereby regulating LTCC expression, inhibiting calcium overload, and ultimately reducing MIRI.

Ginsenoside Rg1 attenuates cerebral ischemia-reperfusion injury due to inhibition of NOX2-mediated calcium homeostasis dysregulation in mice

BackgroundThe incidence of ischemic cerebrovascular disease is increasing in recent years and has been one of the leading causes of neurological dysfunction and death. Ginsenoside Rg1 has been found to protect against neuronal damage in many neurodegenerative diseases. However, the effect and mechanism by which Rg1 protects against cerebral ischemia-reperfusion injury (CIRI) are not fully understood. Here, we report the neuroprotective effects of Rg1 treatment on CIRI and its possible mechanisms in mice. MethodsA bilateral common carotid artery ligation was used to establish a chronic CIRI model in mice. HT22 cells were treated with Rg1 after OGD/R to study its effect on [Ca2+]i. The open-field test and pole-climbing experiment were used to detect behavioral injury. The laser speckle blood flowmeter was used to measure brain blood flow. The Nissl and H&E staining were used to examine the neuronal damage. The Western blotting was used to examine MAP2, PSD95, Tau, p-Tau, NOX2, PLC, p-PLC, CN, NFAT1, and NLRP1 expression. Calcium imaging was used to test the level of [Ca2+]i. ResultsRg1 treatment significantly improved cerebral blood flow, locomotion, and limb coordination, reduced ROS production, increased MAP2 and PSD95 expression, and decreased p-Tau, NOX2, p-PLC, CN, NFAT1, and NLRP1 expression. Calcium imaging results showed that Rg1 could inhibit calcium overload and resist the imbalance of calcium homeostasis after OGD/R in HT22 cells. ConclusionRg1 plays a neuroprotective role in attenuating CIRI by inhibiting oxidative stress, calcium overload, and neuroinflammation.

Synthesis and Biological Evaluation of Falcarinol-Type Analogues as Potential Calcium Channel Blockers.

A series of enantiomers of falcarinol analogues (2) were synthesized using a chiral 1,1'-binaphth-2-ol (BINOL)-based catalytic system. The neuroprotective effects of falcarinol (1a) and its analogues (2) on PC12 cells injured by sodium azide (NaN3) were investigated. The structure-function relationships and possible mechanism were studied. Pretreatment of PC12 cells with falcarinol analogues (R)-2d and (R)-2i for 1 h following addition of NaN3 and culture in a CO2 incubator for 24 h resulted in significant elevation of cell viability, as determined by a CCK-8 assay and Hoechst staining, with reduction of LDH release and MDA content, increase of SOD activity, and decrease of ROS stress, when compared with the activity of natural falcarinol (1a). These observations indicated that the falcarinol analogues (R)-2d and (R)-2i can protect PC12 cells against NaN3-induced apoptosis via increasing resistance to oxidative stress. For the first time, falcarinol (1a) and its analogue (R)-2i were found to have potential L-type calcium channel-blocking activity, as recorded using a manual patch clamp technique on HEK-293 cells stably expressing hCav1.2 (α1C/β2a/α2δ1). These findings suggest that the mechanism of the L-type calcium channel-blocking activity of falcarinol (1a) and its analogue (R)-2i might be involved in neuroprotection by falcarinol-type analogues by inhibiting calcium overload in the upstream of the signaling pathway.

In vitro and in vivo study on prevention of myocardial ischemic injury by taurine.

BackgroundMyocardial ischemia (MI) often causes angina, arrhythmia, and cardiac insufficiency, sometimes resulting in death. Ischemia-induced myocardial tissue damage is attributed to the hypoxic damage of myocardial cells producing apoptosis and decreased proliferation. Taurine has been shown to improve MI, but its mechanism is largely unknown.MethodsIn this study, the relationship between taurine and severity of MI in vivo was evaluated by quantifying myocardial infarct areas and metabolic indicators of myocardial damage and measuring taurine levels in cardiac muscle and plasma by high performance liquid chromatography (HPLC). To elucidate how taurine might suppress ischemic injury, we established an in vitro ischemia model with isolated primary rat cardiomyocytes cultured without serum or glucose and under hypoxia. We evaluated the indicators of MI and damage, including lactic dehydrogenase (LDH), creatine kinase (CK), and cardiac troponin I (cTnI). We also examined the levels of taurine transporter (TauT), cysteine dioxygenase (CDO), and cysteine sulfinate decarboxylase (CSD) proteins involved in transport and synthesis of taurine in the myocardium and those of 2 apoptosis-associated proteins, namely, Bcl-2 associated X protein (BAX) and B-cell lymphoma-2 (Bcl-2).ResultsExposure of myocardial cells to ischemia led to the decrease of taurine content, the suppression of cell proliferation, and led to calcium ion overload and apoptosis. Pretreatment with taurine alleviated the ischemic damage, with concomitant elevation of intracellular taurine concentrations. Molecular mechanism analysis showed that pretreatment with taurine upregulated the TauT, CDO, and CSD, 2 rate-limiting enzymes involved in taurine synthesis. These effects facilitated both taurine transport into cells and taurine synthesis, leading to taurine accumulation. In addition, apoptosis inhibition by taurine appeared to be mediated by upregulated Bcl-2 and downregulated BAX, as well as inhibition of calcium overload by suppression of calcium binding protein.ConclusionsWe demonstrated that TauT is critical for the attenuation of myocardial ischemic damage by taurine, facilitating taurine absorption and synthesis. These findings provided new insights and a theoretical foundation for future studies examining taurine as a potential treatment for MI.

Hydroxysafflor Yellow A Ameliorates Myocardial Ischemia/Reperfusion Injury by Suppressing Calcium Overload and Apoptosis.

Myocardial ischemia/reperfusion injury (MI/RI) is an urgent problem with a great impact on health globally. However, its pathological mechanisms have not been fully elucidated. Hydroxysafflor yellow A (HSYA) has a protective effect against MI/RI. This study is aimed at further clarifying the relationship between HSYA cardioprotection and calcium overload as well as the underlying mechanisms. We verified the protective effect of HSYA on neonatal rat primary cardiomyocytes (NPCMs) and human-induced pluripotent stem cell-derived cardiomyocytes (hiPSC-CMs) from hypoxia-reoxygenation (HR) injury. To explore the cardioprotective mechanism of HSYA, we employed calcium fluorescence, TUNEL assay, JC-1 staining, and western blotting. Finally, cardio-ECR and patch-clamp experiments were used to explain the regulation of L-type calcium channels (LTCC) in cardioprotection mediated by HSYA. The results showed that HSYA reduced the levels of myocardial enzymes and protected NPCMs from HR injury. HSYA also restored the contractile function of hiPSC-CMs and field potential signal abnormalities caused by HR and exerted a protective effect on cardiac function. Further, we demonstrated that HSYA protects cardiomyocytes from HR injury by decreasing mitochondrial membrane potential and inhibiting apoptosis and calcium overload. Patch-clamp results revealed that MI/RI caused a sharp increase in calcium currents, which was inhibited by pretreatment with HSYA. Furthermore, we found that HSYA restored contraction amplitude, beat rate, and field potential duration of hiPSC-CMs, which were disrupted by the LTCC agonist Bay-K8644. Patch-clamp experiments also showed that HSYA inhibits Bay-K8644-induced calcium current, with an effect similar to that of the LTCC inhibitor nisoldipine. Therefore, our data suggest that HSYA targets LTCC to inhibit calcium overload and apoptosis of cardiomyocytes, thereby exerting a cardioprotective effect and reducing MI/RI injury.

Ginsenoside Rb1 ameliorates cardiotoxicity triggered by aconitine via inhibiting calcium overload and pyroptosis

BackgroundAconitine-induced cardiotoxicity limits the clinical treatment of cardiotonic, cancers and immune-related diseases. Ginsenoside Rb1 (Rb1) is an active ingredient of traditional Chinese medicine with cardioprotective effect. PurposeThis study aims to study the mechanism of aconitine cardiotoxicity and the detoxification mechanism of Rb1.Study Design: MethodsThe regulatory effect of Rb1 on aconitine was evaluated in vitro and in vivo by myocardial enzyme indicators, pathological analysis, CardioECR detection, calcium transient analysis, western blotting and immunohistochemistry. ResultsRb1 (10, 20, 40 mg/kg) alleviated apoptotic myocardial damage caused by aconitine in rats. Furthermore, Rb1 (25, 50, 100 μM) restored the contractile function and field potential of human induced pluripotent stem cell-derived cardiomyocytes (hiPSC-CMs) by regulating calcium channels and reduced myocardial cell damage by inhibiting the calcium transients of adult rat ventricular myocytes (ARVMs). Rb1 significantly reduced calcium levels in hiPSC-CMs, directly indicating that aconitine-induced calcium overload was alleviated by Rb1. Further, aconitine caused calcium overload by changing the expression of calcium pathway proteins, while Rb1 effectively restored calcium homeostasis. In addition, Rb1 also had a cardioprotective role by inhibiting cell pyroptosis. These results suggested that the maintenance of calcium homeostasis helped to suppress the inflammatory response related to pyroptosis of the heart. ConclusionAconitine-induced cardiotoxicity can be alleviated by Rb1 via restoring calcium homeostasis and inhibiting apoptosis and pyroptosis.

Calenduloside E suppresses calcium overload by promoting the interaction between L-type calcium channels and Bcl2-associated athanogene 3 to alleviate myocardial ischemia/reperfusion injury

IntroductionIntracellular calcium overload is an important contributor to myocardial ischemia/reperfusion (MI/R) injury. Total saponins of the traditional Chinese medicinal plant Aralia elata (Miq.) Seem. (AS) are beneficial for treating MI/R injury, and Calenduloside E (CE) is the main active ingredient of AS. ObjectivesThis study aimed to investigate the effects of CE on MI/R injury and determine its specific regulatory mechanisms. MethodsTo verify whether CE mediated cardiac protection in vivo and in vitro, we performed MI/R surgery in SD rats and subjected neonatal rat ventricular myocytes (NRVMs) to hypoxia-reoxygenation (HR). CE’s cardioprotective against MI/R injury was detected by Evans blue/TTC staining, echocardiography, HE staining, myocardial enzyme levels. Impedance and field potential recording, and patch-clamp techniques of human-induced pluripotent stem cell-derived cardiomyocytes (hiPSC-CMs) were used to detect the function of L-type calcium channels (LTCC). The mechanisms underlying between CE and LTCC was studied through western blot, immunofluorescence, and immunohistochemistry. Drug affinity responsive target stability (DARTS) and co-immunoprecipitation (co-IP) used to further clarify the effect of CE on LTCC and BAG3. ResultsWe found that CE protected against MI/R injury by inhibiting calcium overload. Furthermore, CE improved contraction and field potential signals of hiPSC-CMs and restored sarcomere contraction and calcium transient of adult rat ventricular myocytes (ARVMs). Moreover, patch-clamp data showed that CE suppressed increased L-type calcium current (ICa,L) caused by LTCC agonist, proving that CE could regulate calcium homeostasis through LTCC. Importantly, we found that CE promoted the interaction between LTCC and Bcl2-associated athanogene 3 (BAG3) by co-IP and DARTS. ConclusionOur results demonstrate that CE enhanced LTCC-BAG3 interaction to reduce MI/R induced-calcium overload, exerting a cardioprotective effect.

SERCA Overexpression Improves Mitochondrial Quality Control and Attenuates Cardiac Microvascular Ischemia-Reperfusion Injury

Despite significant advances in the treatment of myocardial ischemia-reperfusion (I/R) injury, coronary circulation is a so far neglected target of cardioprotection. In this study, we investigated the molecular mechanisms underlying I/R injury to cardiac microcirculation. Using gene delivery, we analyzed microvascular protective effects of sarcoplasmic/endoplasmic reticulum Ca2+-ATPase (SERCA) on the reperfused heart and examined the role of SERCA in regulating mitochondrial quality control in cardiac microvascular endothelial cells (CMECs). Our data showed that SERCA overexpression attenuates lumen stenosis, inhibits microthrombus formation, reduces inflammation response, and improves endothelium-dependent vascular relaxation. In vitro experiments demonstrated that SERCA overexpression improves endothelial viability, barrier integrity, and cytoskeleton assembly in CMECs. Mitochondrial quality control, including mitochondrial fusion, mitophagy, bioenergetics, and biogenesis, were disrupted by I/R injury but were restored by SERCA overexpression. SERCA overexpression also restored mitochondrial quality control by inhibiting calcium overload, inactivating xanthine oxidase (XO), and reducing intracellular/mitochondrial reactive oxygen species (ROS). Administration of exogenous XO or a calcium channel agonist abolished the protective effects of SERCA overexpression on mitochondrial quality control and offset the beneficial effects of SERCA overexpression after cardiac microvascular I/R injury. These findings indicate that SERCA overexpression may be an effective approach to targeting cardiac microvascular I/R injury by regulating calcium/XO/ROS signaling and preserving mitochondrial quality control.

[Research progress on saponins in Panax notoginseng and their molecular mechanism of anti-cerebral ischemia].

Ischemic stroke is the most common form of stroke and one of the main diseases leading to death and disability in the world. Its pathological process is complex and changeable as a result of the interaction of multiple pathological links, such as oxidative stress, apoptosis and inflammation. Traditional Chinese medicine Notoginseng Radix et Rhizoma is the dried roots and rhizomes of Panax notoginseng. In clinic, it is mainly used for the treatment of diseases of cardio-cerebral system and vascular system. Recent studies have shown that total saponins of P. notoginseng, the main active ingredients of P. notoginseng against cerebral ischemia, are complex, and can interfere with the enzyme-promoted cascade reaction through multiple pathways, multiple links and multiple targets, so as to exert its physiological effect. Therefore, it has become a hotspot in studies for prevention and treatment of cerebral ischemia. At present, a great advance has been made in studies on the mechanism of anti-cerebral ischemia of P. notoginseng saponins, but more in-depth studies are needed because of its complex mechanism. Therefore, in this paper, a total of 165 kinds of P. notoginseng saponins were summarized, and simply divided into protopanaxadiol saponins(55 species), protopanaxadiol saponins(37 species) and special structural type saponins(73 species) according to their structural types, so as to provide reference for further studies of P. notoginseng saponins. In addition, the effect of P. notoginseng on cerebral ischemia is clear, but its mechanism remains to be further explored. This paper summarizes the mechanism of P. notoginseng saponins against cerebral ischemia in five aspects: antioxidant stress, reduction of apoptosis, reduction of inflammatory reaction, inhibition of calcium overload and protection of blood-brain barrier. Four kinds of drugs commonly used in the treatment of cerebral ischemia were summarized, in order to provide a theoretical basis for further development and utilization of P. notoginseng saponins in the treatment of cerebral ischemia.

Neurotoxic effects of aflatoxin B1 on human astrocytes in vitro and on glial cell development in zebrafish in vivo

Aflatoxin B1 is one of the well-known mycotoxins and mainly found in contaminated animal feed and various agricultural products inducing acute and chronic toxicology, tumor, and abnormal neural development. However, the effects of aflatoxin B1 on the human brain, especially on astrocytes, have not been studied in depth. In the present study, we studied the neurotoxic effects of aflatoxin B1, in vitro and in vivo. Aflatoxin B1 decreased the proliferation and stopped cell cycle progression at the sub G0/G1 stage with an increase in BAX, BAK, and cytochrome c proteins in human astrocytes. In addition, it increased the mitochondrial depolarization, oxidative stress, and calcium influx in both the cytosol and mitochondria. Surprisingly, inhibition of calcium overload in the cytosol and mitochondria, using calcium chelators and an inhibitor, partially rescued the proliferation of aflatoxin B1-treated astrocytes. Based on the toxicity assays using zebrafish models, aflatoxin B1 decreased the embryo survival rate with physiological changes and an increase in the caspase and tp53 genes. It also decreased the expression of gfap, mbp, and olig2 in the transgenic zebrafish embryo’s brain and axon. Our results revealed the specific mechanism of the neurotoxic effects of aflatoxin B1 on human astrocytes and zebrafish glial cells.

Antidepressant-Like Effect and Mechanism of Action of Honokiol on the Mouse Lipopolysaccharide (LPS) Depression Model

There is growing evidence that neuroinflammation is closely linked to depression. Honokiol, a biologically active substance extracted from Magnolia officinalis, which is widely used in traditional Chinese medicine, has been shown to exert significant anti-inflammatory effects and improve depression-like behavior caused by inflammation. However, the specific mechanism of action of this activity is still unclear. In this study, the lipopolysaccharide (LPS) mouse model was used to study the effect of honokiol on depression-like behavior induced by LPS in mice and its potential mechanism. A single administration of LPS (1 mg/kg, intraperitoneal injection) increased the immobility time in the forced swimming test (FST) and tail suspension test (TST), without affecting autonomous activity. Pretreatment with honokiol (10 mg/kg, oral administration) for 11 consecutive days significantly improved the immobility time of depressed mice in the FST and TST experiments. Moreover, honokiol ameliorated LPS-induced NF-κB activation in the hippocampus and significantly reduced the levels of the pro-inflammatory cytokines; tumor necrosis factor α (TNF-α), interleukin 1β (IL-1β), and interferon γ (IFN-γ). In addition, honokiol inhibited LPS-induced indoleamine 2,3-dioxygenase (IDO) activation and quinolinic acid (a toxic product) increase and reduced the level of free calcium in brain tissue, thereby inhibiting calcium overload. In summary, our results indicate that the anti-depressant-like effects of honokiol are mediated by its anti-inflammatory effects. Honokiol may inhibit the LPS-induced neuroinflammatory response through the NF-κB signaling pathway, reducing the levels of related pro-inflammatory cytokines, and furthermore, this may affect tryptophan metabolism and increase neuroprotective metabolites.

Compound anisodine affects the proliferation and calcium overload of hypoxia-induced rat retinal progenitor cells and brain neural stem cells via the p-ERK1/2/HIF-1α/VEGF pathway.

As a Traditional Chinese Medicine, compound anisodine (CA) has previously been shown to regulate the vegetative nervous system, improve microcirculation and scavenge reactive oxygen species, and has been commonly utilized as a neuroprotective agent to treat ischemic optic neuropathy and choroidoretinopathy. The present study aimed to investigate the neuroprotective effects of CA on the proliferation and calcium overload of hypoxia-induced rat retinal progenitor cells (RPCs) and brain neural stem cells (BNSCs) harvested from neonatal Sprague-Dawley rats. Cells were treated with CA at 0.126, 0.252, 0.505 or 1.010 g/l for four hours prior to or after hypoxia (<1% oxygen) for four h, followed by re-oxygenation for four hours; a normal control group and a CA-untreated hypoxia model group were also included. An MTT assay demonstrated that the cell viability was markedly improved following treatment with 0.126–1.010 g/l CA, compared with that in the hypoxia model group (P<0.05). Bromodeoxyuridine (BrdU) immunocytochemical staining and flow cytometry indicated that after culture in hypoxia for 4 h, the number of BrdU+ RPCs and BNSCs was significant decreased, as well as the cell population in S+G2 phase of the cell cycle, which was significantly attenuated by treatment with 1.010 g/l CA for 4 h prior to hypoxia (P<0.05). Furthermore, laser scanning confocal microscopy showed that the intracellular calcium concentration in hypoxia-cultured RPCs and BNSCs was markedly increased, which was attenuated by 0.126–1.010 g/l CA in a concentration-dependent manner (P<0.05). Furthermore, western blot analysis demonstrated that after hypoxia, the protein levels of hypoxia-inducible factor (HIF)-1α and vascular endothelial growth factor (VEGF) were upregulated in RPCs and BNSCs, whereas phosphorylated extracellular signal-regulated kinase (phospho-ERK 1/2Thr202/Tyr204) and Cyclin D1 were downregulated; of note, treatment with 1.010 g/l CA significantly attenuated these changes (P<0.05). The results of the present study suggested that CA may improve the proliferation and inhibit calcium overload in hypoxia-induced RPCs and BNSCs by altering the protein levels of Cyclin D1 as well as signaling through the p-ERK1/2/HIF-1α/VEGF pathway.

Mitigation Effect of Proanthocyanidin on Secondary Heart Injury in Rats Caused by Mechanical Trauma

Multiple organ dysfunctional syndrome secondary to mechanical trauma (MT) has attracted considerable research attention. The heart is one of the most important organs of the body, and secondary cardiac insufficiency caused by MT seriously affects the quality of life. This study aims to investigate whether proanthocyanidin can alleviate myocardial injury and improve heart function in the process of MT leading to secondary cardiac insufficiency. Noble-Collip drum wasused to prepare MT model in rats. And myocardial apoptosis index was calculated after TUNEL staining. Ventricular intubation was employed to detect heart function. Changes in myocardial ultrastructure were observed using an electron microscope. ELISA was used to detect the content of TNF-α and reactive oxygen species generated from monocytes and cardiomyocytes. The changes in Ca2+ concentration in cardiomyocyte were observed by confocal microscope. Compared with trauma group, the administration group had a decreased apoptosis index of cardiomyocytes, and increased ±dp/dtmax. Meanwhile, proanthocyanidin can inhibit monocytes’ TNF-α production, and reduce plasma TNF-α concentration. Moreover, proanthocyanidin can attenuate the excessive oxidative stress reaction of cardiomyocyte, and inhibit calcium overload in cardiomyocytes. In conclusion, proanthocyanidin can effectively ease myocardial damage and improve cardiac function, through anti-inflammatory and antioxidant effects in secondary cardiac insufficiency caused by MT.