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Myocardial infarction (MI) is a leading cause of morbidity and mortality worldwide, and endoplasmic reticulum stress (ERS) and mitochondrial Ca2+ overload have been involved in apoptotic cardiomyocyte death during MI. 13-Methylpalmatine (13-Me-PLT) is a natural isoquinoline alkaloid isolated from Coptis chinensis and has not been systematically studied for their potential pharmacological effects in cardiovascular diseases. We conducted the present study to elucidate whether 13-Me-PLT modulates MI pathology in animal MI and cellular hypoxic models, employing state-of-the-art molecular techniques. The results demonstrated that 13-Me-PLT preserved post-ischemic cardiac function and alleviated cardiomyocyte apoptosis. 13-Me-PLT decreased ERS and the communication between ER and mitochondria, which serves as a protective mechanism against mitochondrial Ca2+ overload and structural and functional injuries to mitochondria. Our data revealed mitigating mitochondrial Ca2+ overload and apoptosis by inhibiting CHOP-mediated Ca2+ transfer between inositol 1,4,5-trisphosphate receptor (IP3R) in ER and VDAC1 in mitochondria as an underlying mechanism for 13-Me-PLT action. Furthermore, 13-Me-PLT produced superior effects in alleviating cardiac dysfunction and apoptosis post-MI to diltiazem and palmatine. Collectively, our research suggests that the CHOP/IP3R/VDAC1 signaling pathway mediates ER-mitochondrial Ca2+ transfer and 13-Me-PLT activates this axis to maintain cellular and organellar Ca2+ homeostasis, protecting against ischemic myocardial injury. These findings may offer an opportunity to develop new agents for the therapy of ischemic heart disease.
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Strengthening tumor cellular adhesion through regulating the concentration of extracellular Ca2+ is highly challenging and promising for antimetastasis. Herein, a pH-responsive conjugated polymer-calcium composite nanoparticle (PFV/CaCO3/PDA@PEG) is developed for calcium-mediated cell adhesion enhancement-based antimetastasis and reactive oxygen species (ROS)-triggered calcium overload and photodynamic therapy (PDT) synergistic tumor treatment. PFV/CaCO3/PDA@PEG is mainly equipped with conjugated poly(fluorene-co-vinylene) (PFV-COOH)-composited CaCO3 nanoparticles, which can be rapidly decomposed under the tumor acidic microenvironment, effectively releasing Ca2+ and the photosensitizer PFV-COOH. The high extracellular Ca2+ concentration facilitates the generation of dimers between two adjacent cadherin ectodomains, which greatly enhances cell-cell adhesion and suppresses tumor metastasis. The inhibition rates are 97 and 87% for highly metastatic tumor cells 4T1 and MCF-7, respectively. Such a well-designed nanoparticle also contributes to realizing PDT, mitochondrial dysfunction, and ROS-triggered Ca2+ overload synergistic therapy. Furthermore, PFV/CaCO3/PDA@PEG displayed superior in vivo inhibition of 4T1 tumor growth and demonstrated a marked antimetastatic effect by both intravenous and intratumoral injection modes. Thus, this study provides a powerful strategy for calcium-mediated metastasis inhibition for tumor therapy.
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Antineoplásicos , Calcio , Adhesión Celular , Nanopartículas , Fotoquimioterapia , Especies Reactivas de Oxígeno , Nanopartículas/química , Humanos , Animales , Calcio/metabolismo , Adhesión Celular/efectos de los fármacos , Ratones , Especies Reactivas de Oxígeno/metabolismo , Antineoplásicos/farmacología , Antineoplásicos/química , Polímeros/química , Polímeros/farmacología , Fármacos Fotosensibilizantes/farmacología , Fármacos Fotosensibilizantes/química , Femenino , Ratones Endogámicos BALB C , Células MCF-7 , Carbonato de Calcio/química , Carbonato de Calcio/farmacología , Proliferación Celular/efectos de los fármacos , Metástasis de la Neoplasia , Línea Celular Tumoral , Ensayos de Selección de Medicamentos AntitumoralesRESUMEN
Repeated sevoflurane exposure in neonatal mice can leads to neuronal apoptosis and mitochondrial dysfunction. The mitochondria are responsible for energy production to maintain homeostasis in the central nervous system. The mitochondria-associated endoplasmic reticulum membrane (MAM) is located between the mitochondria and endoplasmic reticulum (ER), and it is critical for mitochondrial function and cell survival. MAM malfunction contributes to neurodegeneration, however, whether it is involved in sevoflurane-induced neurotoxicity remains unknown. Our study demonstrated that repeated sevoflurane exposure induced mitochondrial dysfunction and dampened the MAM structure. The upregulated ER-mitochondria tethering enhanced Ca2+ transition from the cytosol to the mitochondria. Overload of mitochondrial Ca2+ contributed to opening of the mitochondrial permeability transition pore (mPTP), which caused neuronal apoptosis. Mitofusin 2(Mfn2), a key regulator of ER-mitochondria contacts, was found to be suppressed after repeated sevoflurane exposure, while restoration of Mfn2 expression alleviated cognitive dysfunction due to repeated sevoflurane exposure in the adult mice. These evidences suggest that sevoflurane-induced MAM malfunction is vulnerable to Mfn2 suppression, and the enhanced ER-mitochondria contacts promotes mitochondrial Ca2+ overload, contributing to mPTP opening and neuronal apoptosis. This paper sheds light on a novel mechanism of sevoflurane-induced neurotoxicity. Furthermore, targeting Mfn2-mediated regulation of the MAM structure and mitochondrial function may provide a therapeutic advantage in sevoflurane-induced neurodegeneration.
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Retículo Endoplásmico , GTP Fosfohidrolasas , Mitocondrias , Sevoflurano , Animales , Sevoflurano/toxicidad , Sevoflurano/farmacología , GTP Fosfohidrolasas/metabolismo , Ratones , Retículo Endoplásmico/efectos de los fármacos , Retículo Endoplásmico/metabolismo , Mitocondrias/efectos de los fármacos , Mitocondrias/metabolismo , Ratones Endogámicos C57BL , Apoptosis/efectos de los fármacos , Anestésicos por Inhalación/toxicidad , Anestésicos por Inhalación/farmacología , Masculino , Calcio/metabolismo , Membranas Intracelulares/efectos de los fármacos , Membranas Intracelulares/metabolismo , Proteínas de Transporte de Membrana Mitocondrial/metabolismo , Proteínas de Transporte de Membrana Mitocondrial/efectos de los fármacosRESUMEN
Breast cancer treatment has been a global puzzle, and apoptosis strategies based on mitochondrial Ca2+ overload have attracted extensive attention. However, various limitations of current Ca2+ nanogenerators make it difficult to maintain effective Ca2+ overload concentrations. Here, we constructed a multimodal Ca2+ nano-modulator that, for the first time, combined photothermal therapy (PTT) and mitochondrial Ca2+ overload strategies to inhibit tumor development. By crosslinking sodium alginate (SA) on the surface of calcium carbonate (CaCO3) nanoparticles encapsulating with Cur and ICG, we prepared a synergistic Ca2+ nano-regulator SA/Cur@CaCO3-ICG (SCCI). In vitro studies have shown that SCCI further enhanced photostability while preserving the optical properties of ICG. After uptake by tumor cells, SCCI can reduce mitochondrial membrane potential and down-regulate ATP production by producing large amounts of Ca2+ at low pH. Near-infrared light radiation (NIR) laser irradiation made the tumor cells heat up sharply, which not only accelerated the decomposition of CaCO3, but also produced large amounts of reactive oxygen species (ROS) followed by cell apoptosis. In vivo studies have revealed that the Ca2+ nano-regulators had excellent targeting, biocompatibility, and anti-tumor effects, which can significantly inhibit the proliferation of tumor cells and play a direct killing effect. These findings indicated that therapeutic strategies based on ionic interference and PTT had great therapeutic potential, providing new insights into antitumor therapy.
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Neoplasias de la Mama , Nanopartículas , Fotoquimioterapia , Humanos , Femenino , Neoplasias de la Mama/terapia , Verde de Indocianina/química , Fototerapia , Nanopartículas/química , Homeostasis , Línea Celular TumoralRESUMEN
Mitochondria are specialized organelles, which serve as the "Power House" to generate energy for maintaining heart function. These organelles contain various enzymes for the oxidation of different substrates as well as the electron transport chain in the form of Complexes I to V for producing ATP through the process of oxidative phosphorylation (OXPHOS). Several studies have shown depressed OXPHOS activity due to defects in one or more components of the substrate oxidation and electron transport systems which leads to the depletion of myocardial high-energy phosphates (both creatine phosphate and ATP). Such changes in the mitochondria appear to be due to the development of oxidative stress, inflammation, and Ca2+-handling abnormalities in the failing heart. Although some investigations have failed to detect any changes in the OXPHOS activity in the failing heart, such results appear to be due to a loss of Ca2+ during the mitochondrial isolation procedure. There is ample evidence to suggest that mitochondrial Ca2+-overload occurs, which is associated with impaired mitochondrial OXPHOS activity in the failing heart. The depression in mitochondrial OXPHOS activity may also be due to the increased level of reactive oxygen species, which are formed as a consequence of defects in the electron transport complexes in the failing heart. Various metabolic interventions which promote the generation of ATP have been reported to be beneficial for the therapy of heart failure. Accordingly, it is suggested that depression in mitochondrial OXPHOS activity plays an important role in the development of heart failure.
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Chlorpyrifos (CPF) is a typical organophosphate insecticide known to has serious toxicological effects on aquatic animals and causes many environmental contamination problems. To assess the effects of CPF on the epithelioma papulosum cyprini (EPC) cells of the common carps from the point of calcium ion (Ca2+) transport, the CPF-exposed EPC models were primarily established, and both AO/EB staining and Annexin V/PI assay with flow cytometry analysis were subsequently implemented to identify that CPF-induced EPC cell apoptosis, in consistent with the up-regulated expression of BAX, Cyt-c, CASP3 and CASP9, and down-regulated BCL-2 expression. Then, Mag-Fluo-4 AM, Fluo-4 AM and Rhod-2 AM staining probes were co-stained with ER-Tracker Red and Mito-Tracker Green applied to image cellular Ca2+ flux, illuminating Ca2+ depleted from ER and flux into mitochondria, resulting in ER stress and mitochondrial dysfunction. Additionally, 2-Aminoethyl Diphenylborinate (2-APB), 4-Phenylbutyric acid (4-PBA) and Dorsomorphin (Compound C) were performed as the inhibitor of Ca2+ transition, ER stress and AMPK phosphorylation, suggesting CPF-mediated Ca2+ overload triggered ER stress. And the over-generation of Mito-ROS intensified oxidative stress, promoting the phosphorylation of AMPK and deteriorating cell apoptotic death. The results of this study demonstrated Ca2+ overload-dependent mitochondrial dysfunction engages in the CPF-induced apoptosis, providing a novel concept for investigating the toxicity of CPF as environmental pollution on aquatic organisms.
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Dibutyl phthalate (DBP) is a typical plasticizer and is widely used in industrial manufacturing. DBP has been reported to be cardiotoxic, manifested by oxidative stress and inflammatory damage. However, the potential mechanism of heart damage caused by DBP remains unclear. By in vivo and in vitro experiments, first, this study demonstrated that DBP induced endoplasmic reticulum (ER) stress, mitochondrial damage, and pyroptosis in cardiomyocytes; second, it was confirmed that the ER stress increased mitochondrial-associated ER membrane (MAM), which led to mitochondrial damage by abnormalizing Ca2+ transfer within MAMs; finally, it was confirmed that mitochondrial reactive oxygen species (mtROS) production was increased after mitochondrial damage, which activated NLRP3 inflammasome and pyroptosis in cardiomyocytes. In summary, ER stress is the initiation of DBP cardiotoxicity, which leads to mitochondrial damage by disrupting Ca2+ transfer from ER to mitochondria. Subsequently, released mtROS promotes the activation of NLRP3 inflammasome and pyroptosis, eventually leading to heart damage.
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Dibutil Ftalato , Lesiones Cardíacas , Humanos , Dibutil Ftalato/metabolismo , Piroptosis , Inflamasomas/metabolismo , Proteína con Dominio Pirina 3 de la Familia NLR , Mitocondrias , Retículo Endoplásmico/metabolismo , Lesiones Cardíacas/metabolismoRESUMEN
Severe hypoxia triggers apoptosis leads to myofibers loss and is attributable to impaired intracellular calcium (iCa2+ ) homeostasis, resulting in reduced muscle activity. Hypoxia increases intracellular Ca2+ by activating the release of Ca2+ from iCa2+ stores, however, the effect of increased [iCa2+ ] on the mitochondria of muscle cells at high-altitude hypoxia is largely unexplored. This study examined mitochondrial Ca2+ overload due to altered expression of mitochondrial calcium uptake 1 (MICU1), that is, a gatekeeper of the mitochondrial Ca2+ uniporter, impaired mitochondrial membrane potential (ΔΨm). p53 stabilization and its translocation to the mitochondria were observed following disrupted mitochondrial membrane integrity in myoblasts under hypoxia. Furthermore, the downstream effects of p53 led to the upregulation of proapoptotic proteins (Bax, Caspase-3, and cytochrome C) in myoblasts under hypoxia. Nanocurcumin-pyrroloquinoline quinone formulation (NCF; Indian patent no. 302877), developed to address hypoxia-induced consequences, was found to be beneficial in maintaining mitochondrial Ca2+ homeostasis and limiting p53 translocation into mitochondria under hypoxia in muscle myoblasts. NCF treatment also modulates heat shock proteins and apoptosis-regulating protein expression in myoblasts. Conclusively, we proposed that mitochondrial Ca2+ overload due to altered MICU1 expression intensifies apoptosis and mitochondrial dysfunctionality. The study also reported that NCF could improve mitochondrial [Ca2+ ] homeostasis and antiapoptotic ability in C2C12 myoblasts under hypoxia.
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Calcio , Proteína p53 Supresora de Tumor , Humanos , Calcio/metabolismo , Proteína p53 Supresora de Tumor/genética , Proteína p53 Supresora de Tumor/metabolismo , Proteostasis , Mitocondrias/metabolismo , Mioblastos , Apoptosis , Hipoxia/metabolismo , Proteínas de Transporte de Membrana Mitocondrial/metabolismo , Potencial de la Membrana MitocondrialRESUMEN
OBJECTIVE: Uncorrected obesity is accompanied by unfavorable structural and functional changes in the heart, known as obesity cardiomyopathy. Recent evidence has revealed a crucial role for mitochondria-associated endoplasmic reticulum membranes (MAMs) in obesity-induced cardiac complication. Syntaxin 17 (STX17) serves as a scaffolding molecule localized on MAMs although its role in obesity heart complication remains elusive. METHODS AND MATERIALS: This study examined the role of STX17 in MAMs and mitochondrial Ca2+ homeostasis in HFD-induced obesity cardiomyopathy using tamoxifen-induced cardiac-specific STX17 knockout (STX17cko) and STX17 overexpression mice using intravenously delivered recombinant adeno-associated virus serotype-9 (AAV9-cTNT-STX17). RESULTS: STX17 levels were significantly elevated in plasma from obese patients and heart tissues of HFD-fed mice. Our data revealed that cardiac STX17 knockout alleviated cardiac remodeling and dysfunction in obese hearts without eliciting any notable effect itself, while STX17 overexpression aggravated cardiac dysfunction in obese mice. STX17 deletion and STX17 overexpression annihilated and aggravated, respectively, HFD-induced oxidative stress (O2- production) and mitochondrial injury in the heart. Furthermore, STX17 transfection facilitated obesity-induced MAMs formation in cardiomyocytes and evoked excess mitochondrial Ca2+ influx, dependent upon interaction with mitochondrial Ca2+ uniporter dominant negative ß (MCUb) through Habc domain. Our data also suggested that STX17 promoted ubiquitination and degradation of MCUb through the E3 ligase parkin in the face of palmitate challenging. CONCLUSION: Taken together, our results identified a novel role for STX17 in facilitating obesity-induced MAMs formation, and subsequently mitochondrial Ca2+ overload, mitochondrial O2- accumulation, lipid peroxidation, resulting in cardiac impairment. Our findings denoted therapeutic promises of targeting STX17 in obesity.
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Cardiomiopatías , Mitocondrias , Animales , Ratones , Cardiomiopatías/metabolismo , Mitocondrias/metabolismo , Miocitos Cardíacos/metabolismo , Obesidad/metabolismo , Ubiquitina-Proteína Ligasas/genética , Ubiquitina-Proteína Ligasas/metabolismo , Calcio/metabolismoRESUMEN
Cadmium (Cd) is a toxic metal and also a well-known reproductive toxicant. Cd could induce germ cells apoptosis in mouse testes, however, the mechanism remains unclear. This study designed in vitro using GC-1 spermatogonial (spg) cells to explore the cytotoxicity and the molecular mechanisms induced by cadmium chloride(CdCl2). As expected, CdCl2 elevated the levels of reactive oxygen species (ROS) and induced the release of AIF and Cyt-c from the mitochondria to the cytosol in spermatogonia. Correspondingly, CdCl2 apparently increased the apoptotic rate in spermatogonia. Further researches found that CdCl2 could activate IP3R-MCU pathway, trigger Ca2+ transfer from endoplasmic reticulum to mitochondria, and cause mitochondrial Ca2+ overload. BAPTA acetoxymethyl ester (BAPTA-AM), a calcium chelator, almost completely attenuated IP3R phosphorylation, inhibited the mRNA and protein expression levels of VDAC1, MCU and MCUR1 upregulated by CdCl2, reduced the calcium ion content in the mitochondria. Moreover, BAPTA-AM could decrease the level of ROS, antagonize CdCl2-induced release of AIF and Cyt-c from the mitochondria to the cytosol and alleviate CdCl2-induced apoptosis in spermatogonia. As above, these results provided the evidence that CdCl2 might induce apoptosis of spermatogonia via mitochondrial Ca2+ overload mediated by IP3R-MCU signal pathway.
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Cadmio , Calcio , Masculino , Ratones , Animales , Cadmio/toxicidad , Calcio/metabolismo , Especies Reactivas de Oxígeno/metabolismo , Espermatogonias/metabolismo , Mitocondrias/metabolismo , Transducción de Señal , ApoptosisRESUMEN
Metabolic reprogramming of macrophages initiates the polarization of pro-inflammatory macrophages that exacerbates adipocyte dysfunction and obesity. The imbalance of mitochondrial Ca2+ homeostasis impairs mitochondrial function and promotes inflammation. Connexin 43 (Cx43), a ubiquitous gap junction protein, has been demonstrated to regulate intracellular Ca2+ homeostasis. Here we explored whether macrophage Cx43 affects the obesity process by regulating the polarization of macrophage. HFD treatment induced obesity and exacerbated macrophages infiltration with upregulation of macrophages Cx43. Macrophage-specific knockout of Cx43 reduced HFD-induced obesity by alleviating inflammation in adipose tissue, with less pro-inflammatory M1 macrophage infiltration. Consistently, inhibition or knockdown of Cx43 improved palmitic acid (PA) induced mitochondrial dysfunction, as indicated by improved oxidative phosphorylation (OXPHOS), reduced formation of mitochondria-associated membranes (MAM) and mitochondrial Ca2+ overload. Mechanistically, Cx43 interacted with the mitochondrial Ca2+ uniporter (MCU) and knockdown of Cx43 alleviated PA-induced succinate dehydrogenase (SDH) oxidation by lowering MCU-mediated mitochondrial Ca2+ uptake, which then, promoting the polarization of pro-inflammatory M1 macrophages. Thus, this study identified Cx43 as a mitochondrial Ca2+ regulator that aggravates obesity via promoting macrophages polarized to M1 pro-inflammatory phenotype and suggests that Cx43 might be a promising therapeutic target antagonizing obesity.
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Calcio , Conexina 43 , Humanos , Calcio/metabolismo , Conexina 43/metabolismo , Tejido Adiposo/metabolismo , Macrófagos/metabolismo , Obesidad/metabolismo , Inflamación/metabolismo , Mitocondrias/metabolismoRESUMEN
Pyroptosis provides a new direction and broad prospects for cancer immunotherapy. However, the development of a nanoplatform as a pyroptosis inducer is limited, and the discovery of a new type of nano-pyroptosis inducer for cancer immunotherapy is still imminent. Herein, biodegradable Ca2+ nanomodulators (CaNMs) are prepared as pyroptosis inducers for cancer immunotherapy via mitochondrial Ca2+ overload. The obtained CaNMs can decompose under low pH to release Ca2+ and curcumin, leading to a sudden surge in mitochondrial Ca2+ ions, eventually resulting in pyroptosis. We not only confirm the occurrence of mitochondrial Ca2+ overload-triggered pyroptosis for the first time but also reveal the robust immune responses via CaNMs, along with remarkably suppressing tumor proliferation and lung metastasis. This work will provide new strategies and inspiration for pyroptosis-mediated cancer treatments, greatly contributing to the further development of Ca2+ nanomodulators.
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Curcumina , Neoplasias , Inmunoterapia , Mitocondrias , Neoplasias/terapia , PiroptosisRESUMEN
BACKGROUND: By hindering energy supply pathway for cancer cells, an alternative therapeutic strategy modality is put forward: tumor starvation therapy. And yet only in this blockade of glucose supply which is far from enough to result in sheer apoptosis of cancer cells. RESULTS: In an effort to boost nutrient starvation-dominated cancer therapy, here a novel mitochondrial Ca2+ modulator Alg@CaP were tailor-made for the immobilization of Glucose oxidase for depriving the intra-tumoral glucose, followed by the loading of Curcumin to augment mitochondrial Ca2+ overload to maximize the therapeutic efficiency of cancer starvation therapy via mitochondrial dysfunctions. Also, autophagy inhibitors Obatoclax were synchronously incorporated in this nano-modulator to highlight autophagy inhibition. CONCLUSION: Here, a promising complementary modality for the trebling additive efficacy of starvation therapy was described for cutting off the existing energy sources in starvation therapy through Curcumin-augmented mitochondrial Ca2+ overload and Obatoclax-mediated autophagy inhibition.
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Curcumina , Neoplasias , Inanición , Apoptosis , Autofagia , Línea Celular Tumoral , Curcumina/farmacología , Curcumina/uso terapéutico , Glucosa , Humanos , Indoles , Neoplasias/terapia , Nutrientes , PirrolesRESUMEN
It is now well known that oxidative stress promotes lipid peroxidation, protein oxidation, activation of proteases, fragmentation of DNA and alteration in gene expression for producing myocardial cell damage, whereas its actions for the induction of fibrosis, necrosis and apoptosis are considered to result in the loss of cardiomyocytes in different types of heart disease. The present article is focused on the discussion concerning the generation and implications of oxidative stress from various sources such as defective mitochondrial electron transport and enzymatic reactions mainly due to the activation of NADPH oxidase, nitric oxide synthase and monoamine oxidase in diseased myocardium. Oxidative stress has been reported to promote excessive entry of Ca2+ due to increased permeability of the sarcolemmal membrane as well as depressions of Na+-K+ ATPase and Na+-Ca2+ exchange systems, which are considered to increase the intracellular of Ca2+. In addition, marked changes in the ryanodine receptors and Ca2+-pump ATPase have been shown to cause Ca2+-release and depress Ca2+ accumulation in the sarcoplasmic reticulum as a consequence of oxidative stress. Such alterations in sarcolemma and sarcoplasmic reticulum are considered to cause Ca2+-handling abnormalities, which are associated with mitochondrial Ca2+-overload and loss of myofibrillar Ca2+-sensitivity due to oxidative stress. Information regarding the direct effects of different oxyradicals and oxidants on subcellular organelles has also been outlined to show the mechanisms by which oxidative stress may induce Ca2+-handling abnormalities. These observations support the view that oxidative stress plays an important role in the genesis of subcellular defects and cardiac dysfunction in heart disease.
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Autophagy inhibition could hinder the underlying protective mechanisms in the course of tumor treatment. The advances in autophagy inhibition have driven focus on the functionalized nanoplatforms by combining the current treatment paradigms with complementary autophagy inhibition for enhanced efficacy. Furthermore, Ca2+ overload is also a promising adjuvant target for the tumor treatment by augmenting mitochondrial damage. In this view, complementary mitochondrial Ca2+ overload and autophagy inhibition were first demonstrated as a novel strategy suitable for homing in on the shortage of photodynamic therapy (PDT). We constructed biodegradable tumor-targeted inorganic/organic hybrid nanocomposites (DPGC/OI) synchronously encapsulating IR780 and Obatoclax by biomineralization of the nanofilm method, which consists of pH-triggered calcium phosphate (CP), long circulation phospholipid block copolymers 1,2-distearoyl-sn-glycero-3-phosphoethanolamine (DSPE)-poly(ethylene glycol) (PEG)2000-glucose (DPG). In the presence of the hydrophilic PEG chain and glucose transporter 1 (Glut-1) ligands, DPGC would become an effectively tumor-oriented nanoplatform. Subsequently, IR780 as an outstanding photosensitizer could produce increased amounts of toxic reactive oxygen species (ROS) after laser irradiation. Calcium phosphate (CP) as the Ca2+ nanogenerator could generate Ca2+ at low pH to induce mitochondrial Ca2+ overload. The dysfunction of mitochondria could enhance increased amounts of ROS. Based on the premise that autophagy would degrade dysfunctional organelles to sustain metabolism and homeostasis, which might participate in resistance to PDT, Obatoclax as an autophagy inhibitor would hinder the protective mechanism from cancer cells with negligible toxicity. Such an enhanced PDT via mitochondrial Ca2+ overload and autophagy inhibition could be realized by DPGC/OI.
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Autofagia/efectos de los fármacos , Fosfatos de Calcio/química , Glucosa/química , Indoles/química , Nanocompuestos/química , Fosfatidiletanolaminas/química , Fármacos Fotosensibilizantes/química , Polietilenglicoles/química , Animales , Transporte Biológico , Refuerzo Biomédico , Femenino , Humanos , Indoles/metabolismo , Indoles/farmacología , Ratones Endogámicos BALB C , Mitocondrias/metabolismo , Mitocondrias/ultraestructura , Neoplasias/diagnóstico por imagen , Neoplasias/terapia , Fosfolípidos/química , Fotoquimioterapia , Fármacos Fotosensibilizantes/farmacología , Pirroles/química , Pirroles/metabolismo , Especies Reactivas de Oxígeno/metabolismo , Transducción de Señal , Propiedades de Superficie , Distribución TisularRESUMEN
Multidrug resistance (MDR) is one of the biggest obstacles in cancer chemotherapy. Here, a remarkable reversal of MDR in breast cancer through the synergistic effects of bioactive hydroxyapatite nanoparticles (HAPNs) and doxorubicin (DOX) is shown. DOX loaded HAPNs (DHAPNs) exhibit a 150-fold reduction in IC50 compared with free DOX for human MDR breast cancer MCF-7/ADR cells, and lead to almost complete inhibition of tumor growth in vivo without obvious side effects of free DOX. This high efficacy and specificity could be attributed to multiple action mechanisms of HAPNs. In addition to acting as the conventional nanocarriers to facilitate the cellular uptake and retention of DOX in MCF-7/ADR cells, more importantly, drug-free HAPNs themselves are able to prevent drug being pumped out of MDR cells through targeting mitochondria to induce mitochondrial damage and inhibit ATP production and to trigger sustained mitochondrial calcium overload and apoptosis in MDR cancer cells while not affecting normal cells. The results demonstrate that this simple but versatile bioactive nanoparticle provides a practical approach to effectively overcome MDR.
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Neoplasias de la Mama , Nanopartículas , Doxorrubicina/farmacología , Resistencia a Múltiples Medicamentos , Resistencia a Antineoplásicos , Durapatita , Femenino , Humanos , Células MCF-7RESUMEN
BACKGROUND: Apolipoprotein E4 (apoE4) is a major genetic risk factor of Alzheimer's disease. Its C-terminal-truncated apoE4 (Δ272-299) has neurotoxicity by affecting mitochondrial respiratory function. However, the molecular mechanism(s) underlying the action of apoE4 (Δ272-299) in mitochondrial function remain poorly understood. METHODS: The impact of neuronal apoE4 (Δ272-299) expression on ER stress, mitochondrial-associated membrane (MAM) formation, GRP75, calcium transport and mitochondrial impairment was determined in vivo and in vitro. Furthermore, the importance of ER stress or GRP75 activity in the apoE4 (Δ272-299)-promoted mitochondrial dysfunction in neuron was investigated. RESULTS: Neuronal apoE4 (Δ272-299) expression induced mitochondrial impairment by inducing ER stress and mitochondrial-associated membrane (MAM) formation in vivo and in vitro. Furthermore, apoE4 (Δ272-299) expression promoted GRP75 expression, mitochondrial dysfunction and calcium transport into the mitochondria in neuron, which were significantly mitigated by treatment with PBA (an inhibitor of ER stress), MKT077 (a specific GRP75 inhibitor) or GRP75 silencing. CONCLUSIONS: ApoE4 (Δ272-299) significantly impaired neuron mitochondrial function by triggering ER stress, up-regulating GRP75 expression to increase MAM formation, and mitochondrial calcium overload. Our findings may provide new insights into the neurotoxicity of apoE4 (Δ272-299) against mitochondrial function and uncover new therapeutic targets for the intervention of Alzheimer's disease.
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The proteasome inhibitor (PI), bortezomib (Btz), is effective in treating multiple myeloma and mantle cell lymphoma, but not solid tumors. In this study, we show for the first time that lercanidipine (Ler), an antihypertensive drug, enhances the cytotoxicity of various PIs, including Btz, carfilzomib, and ixazomib, in many solid tumor cell lines by inducing paraptosis, which is accompanied by severe vacuolation derived from the endoplasmic reticulum (ER) and mitochondria. We found that Ler potentiates Btz-mediated ER stress and ER dilation, possibly due to misfolded protein accumulation, in MDA-MB 435S cells. In addition, the combination of Btz and Ler triggers mitochondrial Ca2+ overload, critically contributing to mitochondrial dilation and subsequent paraptotic events, including mitochondrial membrane potential loss and ER dilation. Taken together, our results suggest that a combined regimen of PI and Ler may effectively kill cancer cells via structural and functional perturbations of the ER and mitochondria.
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Bortezomib/farmacología , Calcio/metabolismo , Dihidropiridinas/farmacología , Estrés del Retículo Endoplásmico/efectos de los fármacos , Mitocondrias/efectos de los fármacos , Inhibidores de Proteasoma/farmacología , Apoptosis/efectos de los fármacos , Línea Celular Tumoral , Supervivencia Celular/efectos de los fármacos , Sinergismo Farmacológico , Humanos , Iones/química , Mitocondrias/metabolismo , Vacuolas/efectos de los fármacos , Vacuolas/metabolismoRESUMEN
Coronary microvascular rarefaction, due to endothelial cell (EC) dysfunction, is one of the causes of increased morbidity and mortality in diabetes. Coronary ECs in diabetes are more apoptotic due partly to mitochondrial calcium overload. This study was designed to investigate the role of hexokinase 2 (HK2, an endogenous inhibitor of voltage-dependent anion channel) in coronary endothelial dysfunction in type 2 diabetes. We used mouse coronary ECs (MCECs) isolated from type 2 diabetic mice and human coronary ECs (HCECs) from type 2 diabetic patients to examine protein levels and mitochondrial function. ECs were more apoptotic and capillary density was lower in the left ventricle of diabetic mice than the control. MCECs from diabetic mice exhibited significant increase in mitochondrial Ca2+ concentration ([Ca2+]mito) compared with the control. Among several regulatory proteins for [Ca2+]mito, hexokinase 1 (HK1) and HK2 were significantly lower in MCECs from diabetic mice than control MCECs. We also found that the level of HK2 ubiquitination was higher in MCECs from diabetic mice than in control MCECs. In line with the data from MCECs, HCECs from diabetic patients showed lower HK2 protein levels than HCECs from nondiabetic patients. High-glucose treatment, but not high-fat treatment, significantly decreased HK2 protein levels in MCECs. HK2 overexpression in MCECs of diabetic mice not only lowered the level of [Ca2+]mito, but also reduced mitochondrial reactive oxygen species production toward the level seen in control MCECs. These data suggest that HK2 is a potential therapeutic target for coronary microvascular disease in diabetes by restoring mitochondrial function in coronary ECs.
Asunto(s)
Calcio/metabolismo , Vasos Coronarios/enzimología , Diabetes Mellitus Experimental/enzimología , Diabetes Mellitus Tipo 2/enzimología , Angiopatías Diabéticas/enzimología , Células Endoteliales/enzimología , Hexoquinasa/metabolismo , Mitocondrias/enzimología , Animales , Apoptosis , Glucemia/metabolismo , Vasos Coronarios/patología , Diabetes Mellitus Experimental/genética , Diabetes Mellitus Experimental/patología , Diabetes Mellitus Tipo 2/genética , Diabetes Mellitus Tipo 2/patología , Angiopatías Diabéticas/genética , Angiopatías Diabéticas/patología , Células Endoteliales/patología , Hexoquinasa/genética , Humanos , Masculino , Ratones Endogámicos C57BL , Especies Reactivas de Oxígeno/metabolismo , Ubiquitinación , Regulación hacia ArribaRESUMEN
Epithelial ovarian cancer (EOC) is the leading cause of death among all gynecological cancers. Morusin, a prenylated flavonoid extracted from the root bark of Morus australis, has been reported to exhibit anti-tumor activity against various human cancers except EOC. In the present study, we explored the potential anti-cancer activity of morusin against EOC in vitro and in vivo and possible underlying mechanisms for the first time. We first found that morusin effectively inhibited EOC cell proliferation and survival in vitro and suppressed tumor growth in vivo. Then we observed that treatment of EOC cells with morusin resulted in paraptosis-like cell death, a novel mode of non-apoptotic programmed cell death that is characterized by extensive cytoplasmic vacuolation due to dilation of the endoplasmic reticulum (ER) and mitochondria and lack of apoptotic hallmarks. In addition, we discovered that morusin induced obvious increase in mitochondrial Ca2+ levels, accumulation of ER stress markers, generation of reactive oxygen species (ROS), and loss of mitochondrial membrane potential (Δψm) in EOC cells. Furthermore, pretreatment with 4, 4'-diisothiocyanostilbene-2, 2'-disulfonic acid (DIDS), a chemical inhibitor of voltage-dependent anion channel (VDAC) on the outer mitochondrial membrane, effectively inhibited mitochondrial Ca2+ influx, cytoplasmic vacuolation and cell death induced by morusin in EOC cells. Moreover, DIDS pretreatment also suppressed morusin-induced accumulation of ER stress markers, ROS production and depletion of Δψm. Consistently, tumor xenograft assays showed that co-treatment with DIDS partially reversed the inhibitory effects of morusin on tumor growth in vivo and inhibited the increased levels of ER stress markers induced by morusin in tumor tissues. Collectively, our results suggest that VDAC-mediated Ca2+ influx into mitochondria and subsequent mitochondrial Ca2+ overload contribute to mitochondrial swelling and dysfunction, leading to morusin-induced paraptosis-like cell death in EOC. This study may provide alternative therapeutic strategies for EOC exhibiting resistance to apoptosis.