[Soy isoflavones alleviates calcium overload in rats with cerebral ischemia-reperfusion by inhibiting the Wnt/Ca2+ signaling pathway].

OBJECTIVE: To explore the mechanism by which soybean isoflavone (SI) reduces calcium overload induced by cerebral ischemia-reperfusion (I/R). METHODS: Forty-eight SD rats were randomized into 4 groups to receive sham operation, cerebral middle artery occlusion for 2 h followed by 24 h of reperfusion (I/R model group), or injection of adeno-associated virus carrying Frizzled-2 siRNA or empty viral vector into the lateral cerebral ventricle after modeling.Western blotting was used to examine Frizzled-2 knockdown efficiency and changes in protein expressions in the Wnt/Ca2+ signaling pathway.Calcium levels and pathological changes in the ischemic penumbra (IP) were measured using calcium chromogenic assay and HE staining, respectively.Another 72 SD randomly allocated for sham operation, I/R modeling, or soy isoflavones pretreatment before modeling were examined for regional cerebral blood flow using a Doppler flowmeter, and the cerebral infarct volume was assessed using TTC staining.Pathologies in the IP area were evaluated using HE and Nissl staining, and ROS level, Ca2+ level, cell apoptosis, and intracellular calcium concentration were analyzed using immunofluorescence assay or flow cytometry; the protein expressions of Wnt5a, Frizzled-2, and P-CaMK Ⅱ in the IP were detected with Western blotting and immunohistochemistry. RESULTS: In rats with cerebral I/R, Frizzled-2 knockdown significantly lowered calcium concentration (P < 0.001) and the expression levels of Wnt5a, Frizzled-2, and P-CaMK Ⅱ in the IP area.In soy isoflavones-pretreated rats, calcium concentration, ROS and MDA levels, cell apoptosis rate, cerebral infarct volume, and expression levels of Wnt/Ca2+ signaling pathway-related proteins were all significantly lower while SOD level was higher than those in rats in I/R model group. CONCLUSION: Soy isoflavones can mitigate calcium overload in rats with cerebral I/R by inhibiting the Wnt/Ca2+ signaling pathway.

Targeting TRPM channels for cerebral ischemia-reperfusion injury.

Transient receptor potential melastatin (TRPM) channels have emerged as potential therapeutic targets for cerebral ischemia-reperfusion (I/R) injury. We highlight recent findings on the involvement of TRPM channels in oxidative stress, mitochondrial dysfunction, inflammation, and calcium overload. We also discuss the challenges and future directions in targeting TRPM channels for cerebral I/R injury.

Chondroitin Sulfate-Modified Hydroxyapatite for Caspase-1 Activated Induced Pyroptosis through Ca Overload/ER Stress/STING/IRF3 Pathway in Colorectal Cancer.

Immune checkpoint inhibitors, are the fourth most common therapeutic tool after surgery, chemotherapy, and radiotherapy for colorectal cancer (CRC). However, only a small proportion (≈5%) of CRC patients, those with "hot" (immuno-activated) tumors, benefit from the therapy. Pyroptosis, an innovative form of programmed cell death, is a potentially effective means to mediate a "cold" to "hot" transformation of the tumor microenvironment (TME). Calcium-releasing hydroxyapatite (HAP) nanoparticles (NPs) trigger calcium overload and pyroptosis in tumor cells. However, current limitations of these nanomedicines, such as poor tumor-targeting capabilities and insufficient calcium (Ca) ion release, limit their application. In this study, chondroitin sulfate (CS) is used to target tumors via binding to CD44 receptors and kaempferol (KAE) is used as a Ca homeostasis disruptor to construct CS-HAP@KAE NPs that function as pyroptosis inducers in CRC cells. CS-HAP@KAE NPs bind to the tumor cell membrane, HAP released Ca in response to the acidic environment of the TME, and kaempferol (KAE) enhances the influx of extracellular Ca, resulting in intracellular Ca overload and pyroptosis. This is associated with excessive endoplasmic reticulum stress triggered activation of the stimulator of interferon genes/interferon regulatory factor 3 pathway, ultimately transforming the TME from "cold" to "hot".

Layer-by-Layer Nanoparticles for Calcium Overload in situ Enhanced Reactive Oxygen Oncotherapy.

Background: Challenges such as poor drug selectivity, non-target reactivity, and the development of drug resistance continue to pose significant obstacles in the clinical application of cancer therapeutic drugs. To overcome the limitations of drug resistance in chemotherapy, a viable treatment strategy involves designing multifunctional nano-platforms that exploit the unique physicochemical properties of tumor microenvironment (TME). Methods: Herein, layer-by-layer nanoparticles with polyporous CuS as delivery vehicles, loaded with a sonosensitizer (tetra-(4-aminophenyl) porphyrin, TAPP) and sequentially functionalized with pH-responsive CaCO3, targeting group hyaluronic acid (HA) were designed and synthesized for synergistic treatment involving chemodynamic therapy (CDT), sonodynamic therapy (SDT), photothermal therapy (PTT), and calcium overload. Upon cleavage in an acidic environment, CaCO3 nanoparticles released TAPP and Ca2+, with TAPP generating 1O2 under ultrasound trigger. Exposed CuS produced highly cytotoxic ·OH in response to H2O2 and also exhibited a strong PTT effect. Results: CuS@TAPP-CaCO3/HA (CTCH) delivered an enhanced ability to release more Ca2+ under acidic conditions with a pH value of 6.5, which in situ causes damage to HeLa mitochondria. In vitro and in vivo experiments both demonstrated that mitochondrial dysfunction greatly amplified the damage caused by reactive oxygen species (ROS) to tumor, which strongly confirms the synergistic effect between calcium overload and reactive oxygen therapy. Conclusion: Collectively, the development of CTCH presents a novel therapeutic strategy for tumor treatment by effectively responding to the acidic TME, thus holding significant clinical implications.

Hollow mesoporous calcium peroxide nanoparticles for drug-free tumor calcicoptosis therapy.

Calcium ions (Ca2+) participate in the regulation of cellular apoptosis as a second messenger. Calcium overload, which refers to the abnormal elevation of intracellular Ca2+ concentration, is a factor that can lead to cell death. Here, based on the unique biological effects of Ca2+, hollow mesoporous calcium peroxide nanoparticles (HMCPN) were developed by a facile hydrolysis-precipitation method for drug-free tumor calcicoptosis therapy. The average pore size of the optimized HMCPN17 is 6.4 nm, and the surface area is 81.3 m2/g, which enables HMCPN17 with high drug loading capability. The Ca2+ release from HMCPN17 is much faster at pH 6.8 than that at pH 7.4, which can be ascribed to the acid-triggered conversion of HMCPN17 to Ca2+ and H2O2, indicating a pH-responsive decomposition behavior of HMCPN17. The high drug loading contents of doxorubicin (DOX) and/or sorafenib (SFN) indicate that HMCPN17 can be employed as a generic drug delivery system (DDS). The in vitro and in vivo results reinforce the high calcicoptosis therapeutic efficacy of tumors by our HMCPN17 without drug loading, which can be attributed to the efficient accumulation in tumors and the ability of H2O2 and Ca2+ production at acidic TME. Our HMCPN17 has broad application prospect for construction of multi-drug-loaded composite nanomaterials with diversified functions for the treatment of tumors. STATEMENT OF SIGNIFICANCE: The combination of hollow mesoporous nanomaterials and calcium peroxide nanoparticles has a wide range of applications in the synergistic treatment of tumors. In this study, hollow mesoporous calcium peroxide nanoparticles (HMCPN) were developed based on a simple hydrolysis-precipitation method for tumor calcicoptosis therapy without drug loading. The high drug loading contents of DOX and/or SFN indicate that our HMCPN can serve as a generic DDS. The experimental results demonstrated the high calcicoptosis therapeutic efficacy of HMCPN on tumors even without drug loading.

Mitochondrial mechanisms in the pathogenesis of chronic inflammatory musculoskeletal disorders.

Chronic inflammatory musculoskeletal disorders characterized by prolonged muscle inflammation, resulting in enduring pain and diminished functionality, pose significant challenges for the patients. Emerging scientific evidence points to mitochondrial malfunction as a pivotal factor contributing to these ailments. Mitochondria play a critical role in powering skeletal muscle activity, but in the context of persistent inflammation, disruptions in their quantity, configuration, and performance have been well-documented. Various disturbances, encompassing alterations in mitochondrial dynamics (such as fission and fusion), calcium regulation, oxidative stress, biogenesis, and the process of mitophagy, are believed to play a central role in the progression of these disorders. Additionally, unfolded protein responses and the accumulation of fatty acids within muscle cells may adversely affect the internal milieu, impairing the equilibrium of mitochondrial functioning. The structural discrepancies between different mitochondrial subsets namely, intramyofibrillar and subsarcolemmal mitochondria likely impact their metabolic capabilities and susceptibility to inflammatory influences. The release of signals from damaged mitochondria is known to incite inflammatory responses. Intriguingly, migrasomes and extracellular vesicles serve as vehicles for intercellular transfer of mitochondria, aiding in the removal of impaired mitochondria and regulation of inflammation. Viral infections have been implicated in inducing stress on mitochondria. Prolonged dysfunction of these vital organelles sustains oxidative harm, metabolic irregularities, and heightened cytokine release, impeding the body's ability to repair tissues. This review provides a comprehensive analysis of advancements in understanding changes in the intracellular environment, mitochondrial architecture and distribution, biogenesis, dynamics, autophagy, oxidative stress, cytokines associated with mitochondria, vesicular structures, and associated membranes in the context of chronic inflammatory musculoskeletal disorders. Strategies targeting key elements regulating mitochondrial quality exhibit promise in the restoration of mitochondrial function, alleviation of inflammation, and enhancement of overall outcomes.

Multifunctional calcium-based nanocarriers for synergistic treatment of triple-negative breast cancer.

Targeted breast cancer therapies hold the potential to improve the efficiency of drug delivery to the pathology site without impacting the viability and function of healthy cells. Herein, we developed multifunctional nanocarriers that target simultaneously several downstream signaling processes in triple negative breast cancer cells. The system comprises pH sensitive CaCO3 nanoparticles (NPs) as carriers of the anticancer drug doxorubicin (DOX). The NPs were coated in a layer-by-layer (LbL) fashion using poly-l-lysine and hyaluronic acid to target receptors overexpressed in breast cancer (e.g. CD44, RHAMM). Spheroids of the triple-negative Hs578T cell line were used as a 3D model to assess the therapeutic potential of this system. Our results showed that the NPs act via a synergistic mechanism that combines Ca2+ overload causing cell calcification and DNA damage by DOX. The LbL coating was crucial for the protection of the healthy cells, i.e. it provides NPs with targeting capacity. The overall data suggests that the LbL-coated NPs loaded with DOX hold great potential for the treatment of breast cancer.

Application of capsaicin and calcium phosphate-loaded MOF system for tumor therapy involving calcium overload.

Calcium overload therapy refers to the condition of intracellular Ca2+ overload, which causes mitochondrial damage and leads to the uncontrolled release of apoptotic factors into the cytoplasm through the open mitochondrial permeability pore. Based on this, it is playing an increasingly important role in the field of oncology due to its good efficacy and small side effects. However, the regulation of calcium homeostasis by cancer cells themselves, insufficient calcium ions (Ca2+) in tumor sites and low efficiency of calcium entering tumor have limited its efficacy, resulting in unsatisfactory therapeutic effect. Therefore, a novel CAP/BSA@TCP-ZIF-8 nanoparticle drug carrier system was constructed that can provide Ca2+ from exogenous sources for pH-controlled degradation and drug release at the same time. Both in vivo and in vitro experiments have proved that the nanomaterial can activate TRPV1 channels and provide exogenous Ca2+ to cause Ca2+ overload and apoptosis, thus achieving anti-tumor effects.

Prussian Blue-Derived Nanocomposite Synergized with Calcium Overload for Three-Mode ROS Outbreak Generation to Enhance Oncotherapy.

Calcium overload can lead to tumor cell death. However, because of the powerful calcium channel excretory system within tumor cells, simplistic calcium overloads do not allow for an effective antitumor therapy. Hence, the nanoparticles are created with polyethylene glycol (PEG) donor-modified calcium phosphate (CaP)-coated, manganese-doped hollow mesopores Prussian blue (MMPB) encapsulating glucose oxidase (GOx), called GOx@MMPB@CaP-PEG (GMCP). GMCP with a three-mode enhancement of intratumor reactive oxygen species (ROS) levels is designed to increase the efficiency of the intracellular calcium overload in tumor cells to enhance its anticancer efficacy. The released exogenous Ca2+ and the production of cytotoxic ROS resulting from the perfect circulation of the three-mode ROS outbreak generation that Fenton/Fenton-like reaction and consumption of glutathione from Fe2+/Fe3+and Mn2+/Mn3+ circle, and amelioration of hypoxia from MMPB-guided and GOx-mediated starvation therapy. Photothermal efficacy-induced heat generation owing to MMPB accelerates the above reactions. Furthermore, abundant ROS contribute to damage to mitochondria, and the calcium channels of efflux Ca2+ are inhibited, resulting in a calcium overload. Calcium overload further increases ROS levels and promotes apoptosis of tumor cells to achieve excellent therapy.

Trauma in Neonatal Acute Brain Slices Alters Calcium and Network Dynamics and Causes Calpain-Mediated Cell Death.

Preparing acute brain slices produces trauma that mimics severe penetrating brain injury. In neonatal acute brain slices, the spatiotemporal characteristics of trauma-induced calcium dynamics in neurons and its effect on network activity are relatively unknown. Using multiphoton laser scanning microscopy of the somatosensory neocortex in acute neonatal mouse brain slices (P8-12), we simultaneously imaged neuronal Ca2+ dynamics (GCaMP6s) and cytotoxicity (propidium iodide or PI) to determine the relationship between cytotoxic Ca2+ loaded neurons (GCaMP-filled) and cell viability at different depths and incubation times. PI+ cells and GCaMP-filled neurons were abundant at the surface of the slices, with an exponential decrease with depth. Regions with high PI+ cells correlated with elevated neuronal and neuropil Ca2+ The number of PI+ cells and GCaMP-filled neurons increased with prolonged incubation. GCaMP-filled neurons did not participate in stimulus-evoked or seizure-evoked network activity. Significantly, the superficial tissue, with a higher degree of trauma-induced injury, showed attenuated seizure-related neuronal Ca2+ responses. Calpain inhibition prevented the increase in PI+ cells and GCaMP-filled neurons in the deep tissue and during prolonged incubation times. Isoform-specific pharmacological inhibition implicated calpain-2 as a significant contributor to trauma-induced injury in acute slices. Our results show a calpain-mediated spatiotemporal relationship between cell death and aberrant neuronal Ca2+ load in acute neonatal brain slices. Also, we demonstrate that neurons in acute brain slices exhibit altered physiology depending on the degree of trauma-induced injury. Blocking calpains may be a therapeutic option to prevent acute neuronal death during traumatic brain injury in the young brain.

Maintaining calcium homeostasis as a strategy to alleviate nephrotoxicity caused by evodiamine.

Evodiamine (EVO), the main active alkaloid in Evodia rutaecarpa, was shown to exert various pharmacological activities, especially anti-tumor. Currently, it is considered a potential anti-cancer drug due to its excellent anti-tumor activity, which unfortunately has adverse reactions, such as the risk of liver and kidney injury, when Evodia rutaecarpa containing EVO is used clinically. In the present study, we aim to clarify the potential toxic target organs and toxicity mechanism of EVO, an active monomer in Evodia rutaecarpa, and to develop mitigation strategies for its toxicity mechanism. Transcriptome analysis and related experiments showed that the PI3K/Akt pathway induced by calcium overload was an important step in EVO-induced apoptosis of renal cells. Specifically, intracellular calcium ions were increased, and mitochondrial calcium ions were decreased. In addition, EVO-induced calcium overload was associated with TRPV1 receptor activation. In vivo TRPV1 antagonist and calcium chelator effects were observed to significantly reduce body weight loss and renal damage in mice due to EVO toxicity. The potential nephrotoxicity of EVO was further confirmed by an in vivo test. In conclusion, TRPV1-mediated calcium overload-induced apoptosis is one of the mechanisms contributing to the nephrotoxicity of EVO due to its toxicity, whereas maintaining body calcium homeostasis is an effective measure to reduce toxicity. These studies suggest that the clinical use of EVO-containing herbal medicines should pay due attention to the changes in renal function of patients as well as the off-target effects of the drugs.

Selenium represses microRNA-202-5p/MICU1 aixs to attenuate mercuric chloride-induced kidney ferroptosis.

Mercuric chloride (HgCl2) is a nephrotoxic contaminant that is widely present in the environment. Selenium (Se) can effectively antagonize the biological toxicity caused by heavy metals. Here, in vivo and in vitro models of Se antagonism to HgCl2-induced nephrotoxicity in chickens were established, with the aim of exploring the specific mechanism. Morphological observation and kidney function analysis showed that Se alleviated HgCl2-induced kidney tissue injury and cytotoxicity. The results showed that ferroptosis was the primary mechanism for the toxicity of HgCl2, as indicated by iron overload and lipid peroxidation. On the one hand, Se significantly prevented HgCl2-induced iron overload. On the other hand, Se alleviated the intracellular reactive oxygen species (ROS) levels caused by HgCl2. Subsequently, we focused on the sources of ROS during HgCl2-induced ferroptosis. Mechanically, Se reduced ROS overproduction induced by HgCl2 through mitochondrial calcium uniporter (MCU)/mitochondrial calcium uptake 1 (MICU1)-mediated mitochondrial calcium ion (Ca2+) overload. Furthermore, a dual luciferase reporter assay demonstrated that MICU1 was the direct target of miR-202-5p. Overall, Se represses miR-202-5p/MICU1 axis to attenuate HgCl2-induced kidney ferroptosis.

Dopamine D2 Receptor Activation Blocks GluA2/ROS Positive Feedback Loop to Alienate Chronic-Migraine-Associated Pain Sensitization.

Chronic migraine is a disabling disorder without effective therapeutic medicine. AMPA receptors have been proven to be essential to pathological pain and headaches, but the related regulatory mechanisms in chronic migraine have not yet been explored. In this study, we found that the level of surface GluA2 was reduced in chronic migraine rats. Tat-GluR23Y (a GluA2 endocytosis inhibitor) reduced calcium inward flow and weakened synaptic structures, thus alleviating migraine-like pain sensitization. In addition, the inhibition of GluA2 endocytosis reduced the calcium influx and alleviated mitochondrial calcium overload and ROS generation in primary neurons. Furthermore, our results showed that ROS can induce allodynia and GluA2 endocytosis in rats, thus promoting migraine-like pain sensitization. In our previous study, the dopamine D2 receptor was identified as a potential target in the treatment of chronic migraine, and here we found that dopamine D2 receptor activation suppressed chronic-migraine-related pain sensitization through blocking the GluA2/ROS positive feedback loop in vivo and in vitro. Additionally, ligustrazine, a core component of ligusticum chuanxiong, was shown to target the dopamine D2 receptor, thereby alleviating ROS production and abnormal nociception in CM rats. This study provides valuable insight into the treatment of chronic migraine.

Mitochondrial calcium uniporter promotes kidney aging in mice through inducing mitochondrial calcium-mediated renal tubular cell senescence.

Renal tubular epithelial cell senescence plays a critical role in promoting and accelerating kidney aging and age-related renal fibrosis. Senescent cells not only lose their self-repair ability, but also can transform into senescence-associated secretory phenotype (SASP) to trigger inflammation and fibrogenesis. Recent studies show that mitochondrial dysfunction is critical for renal tubular cell senescence and kidney aging, and calcium overload and abnormal calcium-dependent kinase activities are involved in mitochondrial dysfunction-associated senescence. In this study we investigated the role of mitochondrial calcium overload and mitochondrial calcium uniporter (MCU) in kidney aging. By comparing the kidney of 2- and 24-month-old mice, we found calcium overload in renal tubular cells of aged kidney, accompanied by significantly elevated expression of MCU. In human proximal renal tubular cell line HK-2, pretreatment with MCU agonist spermine (10 µM) significantly increased mitochondrial calcium accumulation, and induced the production of reactive oxygen species (ROS), leading to renal tubular cell senescence and age-related kidney fibrosis. On the contrary, pretreatment with MCU antagonist RU360 (10 µM) or calcium chelator BAPTA-AM (10 µM) diminished D-gal-induced ROS generation, restored mitochondrial homeostasis, retarded cell senescence, and protected against kidney aging in HK-2 cells. In a D-gal-induced accelerated aging mice model, administration of BAPTA (100 µg/kg. i.p.) every other day for 8 weeks significantly alleviated renal tubuarl cell senescence and fibrosis. We conclude that MCU plays a key role in promoting renal tubular cell senescence and kidney aging. Targeting inhibition on MCU provides a new insight into the therapeutic strategy against kidney aging.

NIR-II Absorbed Dithienopyrrole-Benzobisthiadiazole Based Nanosystems for Autophagy Inhibition and Calcium Overload Enhanced Photothermal Therapy.

Although the current cancer photothermal therapy (PTT) can produce a powerful therapeutic effect, tumor cells have been proved a protective mechanism through autophagy. In this study, a novel hybrid theranostic nanoparticle (CaCO3@CQ@pDB NPs, CCD NPs) is designed and prepared by integrating a second near-infrared (NIR-II) absorbed conjugated polymer DTP-BBT (pDB), CaCO3, and autophagy inhibitor (chloroquine, CQ) into one nanosystem. The conjugated polymer pDB with asymmetric donor-acceptor structure shows strong NIR-II absorbing capacity, of which the optical properties and photothermal generation mechanism of pDB are systematically analyzed via molecular theoretical calculation. Under NIR-II laser irradiation, pDB-mediated PTT can produce powerful killing ability to tumor cells. At the same time, heat stimulates a large amount of Ca2+ inflow, causing calcium overload induced mitochondrial damage and enhancing the apoptosis of tumor cells. Besides, the released CQ blocks the self-protection mechanism of tumor cells and greatly enhances the attack of PTT and calcium overload therapy. Both in vitro and in vivo experiments confirm that CCD NPs possess excellent NIR-II theranostic capacity, which provides a new nanoplatform for anti-tumor therapy and builds great potential for future clinical research.

The mitochondrial calcium uniporter inhibitor Ru265 increases neuronal excitability and reduces neurotransmission via off-target effects.

BACKGROUND AND PURPOSE: Excitotoxicity due to mitochondrial calcium (Ca2+) overloading can trigger neuronal cell death in a variety of pathologies. Inhibiting the mitochondrial calcium uniporter (MCU) has been proposed as a therapeutic avenue to prevent calcium overloading. Ru265 (ClRu(NH3)4(µ-N)Ru(NH3)4Cl]Cl3) is a cell-permeable inhibitor of the mitochondrial calcium uniporter (MCU) with nanomolar affinity. Ru265 reduces sensorimotor deficits and neuronal death in models of ischemic stroke. However, the therapeutic use of Ru265 is limited by the induction of seizure-like behaviours. EXPERIMENTAL APPROACH: We examined the effect of Ru265 on synaptic and neuronal function in acute brain slices and hippocampal neuron cultures derived from mice, in control and where MCU expression was genetically abrogated. KEY RESULTS: Ru265 decreased evoked responses from calyx terminals and induced spontaneous action potential firing of both the terminal and postsynaptic principal cell. Recordings of presynaptic Ca2+ currents suggested that Ru265 blocks the P/Q type channel, confirmed by the inhibition of currents in cells exogenously expressing the P/Q type channel. Measurements of presynaptic K+ currents further revealed that Ru265 blocked a KCNQ current, leading to increased membrane excitability, underlying spontaneous spiking. Ca2+ imaging of hippocampal neurons showed that Ru265 increased synchronized, high-amplitude events, recapitulating seizure-like activity seen in vivo. Importantly, MCU ablation did not suppress Ru265-induced increases in neuronal activity and seizures. CONCLUSIONS AND IMPLICATIONS: Our findings provide a mechanistic explanation for the pro-convulsant effects of Ru265 and suggest counter screening assays based on the measurement of P/Q and KCNQ channel currents to identify safe MCU inhibitors.

Qiangxinyin formula protects against isoproterenol-induced cardiac hypertrophy.

Heart failure is a life-threatening cardiovascular disease and characterized by cardiac hypertrophy, inflammation and fibrosis. The traditional Chinese medicine formula Qiangxinyin (QXY) is effective for the treatment of heart failure while the underlying mechanism is not clear. This study aims to identify the active ingredients of QXY and explore its mechanisms protecting against cardiac hypertrophy. We found that QXY significantly protected against isoproterenol (ISO)-induced cardiac hypertrophy and dysfunction in zebrafish. Eight compounds, including benzoylmesaconine (BMA), atractylenolide I (ATL I), icariin (ICA), quercitrin (QUE), psoralen (PRN), kaempferol (KMP), ferulic acid (FA) and protocatechuic acid (PCA) were identified from QXY. PRN, KMP and icaritin (ICT), an active pharmaceutical ingredient of ICA, prevented ISO-induced cardiac hypertrophy and dysfunction in zebrafish. In H9c2 cardiomyocyte treated with ISO, QXY significantly blocked the calcium influx, reduced intracellular lipid peroxidative product MDA, stimulated ATP production and increased mitochondrial membrane potential. QXY also inhibited ISO-induced cardiomyocyte hypertrophy and cytoskeleton reorganization. Mechanistically, QXY enhanced the phosphorylation of Smad family member 2 (SMAD2) and myosin phosphatase target subunit-1 (MYPT1), and suppressed the phosphorylation of myosin light chain (MLC). In conclusion, PRN, KMP and ICA are the main active ingredients of QXY that protect against ISO-induced cardiac hypertrophy and dysfunction largely via the blockage of calcium influx and inhibition of mitochondrial dysfunction as well as cytoskeleton reorganization.

MCU inhibition protects against intestinal ischemia‒reperfusion by inhibiting Drp1-dependent mitochondrial fission.

Intestinal ischemia‒reperfusion (IIR) injury is a common complication of surgery, but clear molecular insights and valuable therapeutic targets are lacking. Mitochondrial calcium overload is an early sign of various diseases and is considered a vital factor in ischemia‒reperfusion injury. The mitochondrial calcium uniporter (MCU), which is located on the inner mitochondrial membrane, is the primary mediator of calcium ion entry into the mitochondria. However, the specific mechanism of MCU in IIR injury remains to be clarified. In this study, we generated an IIR model using C57BL/6 mice and Caco-2 cells and found increases in the calcium levels and MCU expression following IIR injury. The specific inhibition of MCU markedly attenuated IIR injury. Moreover, MCU knockdown alleviates mitochondrial dysfunction by reducing oxidative stress and apoptosis. Mechanistically, MCU knockdown substantially reduced the translocation of Drp1 and thus its binding to Fis1 receptors, resulting in decreased mitochondrial fission. Taken together, our findings demonstrated that MCU is a novel upstream regulator of Drp1 in ischemia‒reperfusion and represents a predictive and therapeutic target for IIR.

Mitochondrial Ca2+ Uniporter-Dependent Energetic Dysfunction Drives Hypertrophy in Heart Failure.

The role of the mitochondrial calcium uniporter (MCU) in energy dysfunction and hypertrophy in heart failure (HF) remains unknown. In angiotensin II (ANGII)-induced hypertrophic cardiac cells we have shown that hypertrophic cells overexpress MCU and present bioenergetic dysfunction. However, by silencing MCU, cell hypertrophy and mitochondrial dysfunction are prevented by blocking mitochondrial calcium overload, increase mitochondrial reactive oxygen species, and activation of nuclear factor kappa B-dependent hypertrophic and proinflammatory signaling. Moreover, we identified a calcium/calmodulin-independent protein kinase II/cyclic adenosine monophosphate response element-binding protein signaling modulating MCU upregulation by ANGII. Additionally, we found upregulation of MCU in ANGII-induced left ventricular HF in mice, and in the LV of HF patients, which was correlated with pathological remodeling. Following left ventricular assist device implantation, MCU expression decreased, suggesting tissue plasticity to modulate MCU expression.