Empagliflozin, a sodium-glucose cotransporter inhibitor enhancing mitochondrial action and cardioprotection in metabolic syndrome.

Metabolic syndrome (MetS) has a large clinical population nowadays, usually due to excessive energy intake and lack of exercise. During MetS, excess nutrients stress the mitochondria, resulting in relative hypoxia in tissues and organs, even when blood supply is not interrupted or reduced, making mitochondrial dysfunction a central pathogenesis of cardiovascular disease in the MetS. Sodium-glucose cotransporter 2 inhibitors were designed as a hyperglycemic drug that acts on the renal tubules to block sugar reabsorption in primary urine. Recently they have been shown to have anti-inflammatory and other protective effects on cardiomyocytes in MetS, and have also been recommended in the latest heart failure guidelines as a routine therapy. Among these inhibitors, empagliflozin shows better clinical promise due to less influence from glomerular filtration rate. This review focuses on the mitochondrial mechanisms of empagliflozin, which underlie the anti-inflammatory and recover cellular functions in MetS cardiomyocytes, including stabilizing calcium concentration, mediating metabolic reprogramming, maintaining homeostasis of mitochondrial quantity and quality, stable mitochondrial DNA copy number, and repairing damaged mitochondrial DNA.

Mitochondrial abnormalities: a hub in metabolic syndrome-related cardiac dysfunction caused by oxidative stress.

Metabolic syndrome (MetS) refers to a group of cardiovascular risk elements comprising insulin resistance, obesity, dyslipidemia, increased glucose intolerance, and increased blood pressure. Individually, all the MetS components can lead to cardiac dysfunction, while their combination generates additional risks of morbidity and mortality. Growing evidence suggests that oxidative stress, a dominant event in cellular damage and impairment, plays an indispensable role in cardiac dysfunction in MetS. Oxidative stress can not only disrupt mitochondrial activity through inducing oxidative damage to mitochondrial DNA, RNA, lipids, and proteins but can also impair cardiomyocyte contractile function via mitochondria-related oxidative modifications of proteins central to excitation-contraction coupling. Furthermore, excessive reactive oxygen species (ROS) generation can lead to the activation of several mitochondria apoptotic signaling pathways, release of cytochrome c, and eventual induction of myocardial apoptosis. This review will focus on such processes of mitochondrial abnormalities in oxidative stress induced cardiac dysfunction in MetS.

Dexmedetomidine Reduces the Lidocaine-Induced Neurotoxicity by Inhibiting Inflammasome Activation and Reducing Pyroptosis in Rats.

Local anesthetic toxicity is closely related to neuronal death and activation of the inflammatory response. Dexmedetomidine (Dex) is an adrenergic α2 receptor agonist that can reduce the neurotoxicity induced by lidocaine. It also has anti-inflammatory effects. However, the mechanism underlying the neuroprotective effects of Dex against lidocaine-induced toxicity remains to be defined. We hypothesized that Dex exerts its neural protective effect through inhibiting inflammasome activation and through anti-pyroptosis effects against local anesthetic-induced nerve injury. In a rat model of lidocaine-induced spinal cord injury, we studied the protective effect of Dex on lidocaine-induced changes in spinal cord function, inflammasome formation and pyroptosis, pro-inflammatory cytokine expression, and protein kinase C (PKC)-δ phosphorylation. Dex reduced lidocaine-induced neurotoxicity and inhibited PKC-δ phosphorylation in the spinal cord of rats. Furthermore, Dex inhibited pyroptosis and inflammasome formation (caspase-1, NLRP3, and apoptosis-associated speck-like protein (ASC)). Finally, Dex attenuated interleukin (IL)-1ß and IL-18 expression, as well as microglia response. In conclusion, Dex can reduce the severity of lidocaine-induced spinal cord injury in rats by inhibiting priming and inflammasome activation and reducing pyroptosis via PKC-δ phosphorylation.

Therapeutic Effects of Coccomyxagloeobotrydiformis on the Metabolic Syndrome in Rats.

BACKGROUND/AIMS: The metabolic syndrome (MS) is a cluster of metabolic changes that carry a high risk of cardiovascular disease (CVD). A newly discovered microalga, coccomyxagloeobotrydiformis (CGD), has been reported to improve ischemic stroke and metabolism-related indicators. We observed the therapeutic effects of CGD on MS and postulated the underlying mechanism. METHODS: A diet-induced MS model in rats was used to observe the therapeutic effects of CGD on MS. Blood-glucose and lipid indices were measured using enzymatic colorimetric kits. A biologic data acquisition and analysis system (BL-420F) was used to evaluate cardiac function. Expression of mitochondrial respiratory chain (MRC) enzymes was measured by immunofluorescence staining. The proteins associated with oxidative stress, apoptosis and inflammation were detected by western blotting. RESULTS: Body weight, abdominal circumference, fasting blood glucose , blood pressure as well as serum levels of total cholesterol, triglycerides and low-density lipoprotein-cholesterol were decreased whereas serum levels of high-density lipoprotein-cholesterol was increased in CGD-treated MS rats. CGD increased left-ventricular systolic pressure, left-ventricular end-diastolic pressure, left-ventricular systolic pressure maximum rate of increase and left-ventricular diastolic pressure maximum rate of decrease in MS rats with cardiovascular complications. CGD up-regulated expression of adenosine monophosphate-activated protein kinase and peroxisome proliferator activated receptor gamma coactivator 1-alpha in the heart, adipose tissue and skeletal muscle. Expression of the MRC subunits of ATPase 6, cytochrome b and succinate dehydrogenase complex, subunit-A was increased whereas that of uncoupling protein-2 decreased in different tissues. CGD showed anti-oxidation effects by increasing expression of superoxide dismutase and decreasing that of malondialdehyde. High expression of Bcl-2 and low expression of Bax and caspase-3 supported the anti-apoptotic effect of CGD on the cardiovascular complications of MS. CONCLUSION: CGD has a therapeutic effect on MS and associated cardiovascular complications by eliciting mitochondrial protection and having anti-oxidation and anti-apoptosis effects. CGD could be used for MS treatment.

p62/SQSTM1 interacts with vimentin to enhance breast cancer metastasis.

The signalling adaptor p62 is frequently overexpressed in numerous cancer types. Here, we found that p62 expression was elevated in metastatic breast cancer and its overexpression correlated with reduced metastasis- and relapse-free survival times. Analysis of p62 expression in breast cancer cell lines demonstrated that high p62 expression was associated with the invasive phenotypes of breast cancer. Indeed, silencing p62 expression attenuated the invasive phenotypes of highly metastatic cells, whereas overexpressing p62 promoted the invasion of non-metastatic cells in in vitro microfluidic model. Moreover, MDA-MB-231 cells with p62 depletion which were grown in a three-dimensional culture system exhibited a loss of invasive protrusions. Consistently, genetic ablation of p62 suppressed breast cancer metastasis in both zebrafish embryo and immunodeficient mouse models, as well as decreased tumourigenicity in vivo. To explore the molecular mechanism by which p62 promotes breast cancer invasion, we performed a co-immunoprecipitation-mass spectrometry analysis and revealed that p62 interacted with vimentin, which mediated the function of p62 in promoting breast cancer invasion. Vimentin protein expression was downregulated upon p62 suppression and upregulated with p62 overexpression in breast cancer cells. Linear regression analysis of clinical breast cancer specimens showed a positive correlation between p62 and vimentin protein expression. Together, our findings provide strong evidence that p62 functions as a tumour metastasis promoter by binding vimentin and promoting its expression. This finding might help to develop novel molecular therapeutic strategies for breast cancer metastasis treatment.

Dexmedetomidine preconditioning attenuates global cerebral ischemic injury following asphyxial cardiac arrest.

BACKGROUND/AIMS: To investigate the protection effect of dexmedetomidine preconditioning on global cerebral ischemic injury following asphyxial cardiac arrest (CA) in rats. METHODS: Seventy-two rats were randomly assigned into three groups, sham group (no asphyxia), control group (asphyxia only), and dexmedetomidine preconditioned group (asphyxia + dexmedetomidine). Dexmedetomidine was administered 5 minutes before an 8 min of asphyxia. Rats were resuscitated by a standardized method. Blood O(2) and CO(2) partial pressures were, pH, base excess (BE), and blood glucose concentration measured before asphyxial CA and 1 h after resuscitation. Neurological deficit score (NDS) was measured at 12, 24, 48, and 72 h after CA. Histopathologic changes in the hippocampal region were observed by H&E staining and histopathologic damage score. Ultrastructural morphology was observed by transmission electron microscopy. HIF-1 and VEGF expression were measured by immunostaining of serial sections obtained from brain tissue. RESULTS: Asphyxial CA -induced global cerebral ischemic decreased PaO(2), pH, BE and increased PaCO(2), blood glucose. Dexmedetomidine preconditioning improved neurologic outcome, which was associated with reduction in histopathologic injury measured by H&E staining, the histopathologic damage score and electron microscopy. Dexmedetomidine preconditioning also elevated HIF-1α and VEGF expression after global cerebral ischemia following asphyxial CA. CONCLUSION: Dexmedetomidine preconditioning protected against cerebral ischemic injury and was associated with upregulation of HIF-1α and VEGF expression.

Ca2+ influx via the Na+/Ca2+ exchanger is enhanced in malignant hyperthermia skeletal muscle.

Malignant hyperthermia (MH) is potentially fatal pharmacogenetic disorder of skeletal muscle caused by intracellular Ca(2+) dysregulation. NCX is a bidirectional transporter that effluxes (forward mode) or influxes (reverse mode) Ca(2+) depending on cellular activity. Resting intracellular calcium ([Ca(2+)]r) and sodium ([Na(+)]r) concentrations are elevated in MH susceptible (MHS) swine and murine muscles compared with their normal (MHN) counterparts, although the contribution of NCX is unclear. Lowering [Na(+)]e elevates [Ca(2+)]r in both MHN and MHS swine muscle fibers and it is prevented by removal of extracellular Ca(2+) or reduced by t-tubule disruption, in both genotypes. KB-R7943, a nonselective NCX3 blocker, reduced [Ca(2+)]r in both swine and murine MHN and MHS muscle fibers at rest and decreased the magnitude of the elevation of [Ca(2+)]r observed in MHS fibers after exposure to halothane. YM-244769, a high affinity reverse mode NCX3 blocker, reduces [Ca(2+)]r in MHS muscle fibers and decreases the amplitude of [Ca(2+)]r rise triggered by halothane, but had no effect on [Ca(2+)]r in MHN muscle. In addition, YM-244769 reduced the peak and area under the curve of the Ca(2+) transient elicited by high [K(+)]e and increased its rate of decay in MHS muscle fibers. siRNA knockdown of NCX3 in MHS myotubes reduced [Ca(2+)]r and the Ca(2+) transient area induced by high [K(+)]e. These results demonstrate a functional NCX3 in skeletal muscle whose activity is enhanced in MHS. Moreover reverse mode NCX3 contributes to the Ca(2+) transients associated with K(+)-induced depolarization and the halothane-triggered MH episode in MHS muscle fibers.

PDK1 Activity Regulates Proliferation, Invasion and Growth of Hemangiomas.

BACKGROUND: Hemangiomas are common vascular endothelial cell tumors. Abnormally activated PI3K/Akt signaling pathway is one of the most important biological characteristics of Hemangioma. 3-phosphoinositide-dependent kinase 1(PDK1), an upstream protein of Akt, regulates the activity of Akt and its downstream kinases. The objective of this study is to explore the effect of PDK1 on malignant vascular tumors and their cell signaling mechanism in mice. METHODS: Mouse Hemangioendothelioma Endothelial Cells (EOMA cells) and Nu/Nu mice were used. The silencing of PDK1 was mediated by lentiviral shRNA. Western blotting, WST-1 proliferation assay, Matrigel invasion assay, and Xenograft vascular tumor model were utilized to examine the effects and mechanism of PDK1 growth, proliferation, and invasion of an Hemangioma. RESULTS: PDK1 deficiency significantly reduced the proliferation and invasion of EOMA cells in vitro, and depressed the growth of vascular tumor in vivo by decreasing the activity of Akt signaling pathway. CONCLUSION: We hypothesize that PDK1 plays a significant role in the progression and growth of vascular tumors and targeting PDK1 may thus be considered in their treatment.

Nonspecific sarcolemmal cation channels are critical for the pathogenesis of malignant hyperthermia.

Malignant hyperthermia (MH) susceptibility has been attributed to a leaky sarcoplasmic reticulum (SR) caused by missense mutations in RYR1 or CACNA1S, and the MH crisis has been attributed solely to massive self-sustaining release of Ca(2+) from SR stores elicited by triggering agents. Here, we show in muscle cells from MH-RyR1(R163C) knock-in mice that increased passive SR Ca(2+) leak causes an enlarged basal influx of sarcolemmal Ca(2+) that results in chronically elevated myoplasmic free Ca(2+) concentration ([Ca(2+)]i) at rest. We discovered that Gd(+3) and GsMTx-4 were more effective than BTP2 or expression of the dominant-negative Orai1(E190Q) in reducing both Ca(2+) entry and [Ca(2+)]i, implicating a non-STIM1/Orai1 SOCE pathway in resetting resting [Ca(2+)]i. Indeed, two nonselective cationic channels, TRPC3 and TRPC6, are overexpressed, and [Na]i is chronically elevated in MH-RyR1(R163C) muscle cells. [Ca(2+)]i and [Na(+)]i are persistently elevated in vivo and further increased by halothane in MH-RyR1(R163C/WT) muscle. These increases are markedly attenuated by local perfusion of Gd(+3) or GsMTx-4 and completely suppressed by dantrolene. These results contribute a new paradigm for understanding MH pathophysiology by demonstrating that nonselective sarcolemmal cation channel activity plays a critical role in causing myoplasmic Ca(2+) and Na(+) overload both at rest and during the MH crisis.-Eltit, J. M., Ding, X., Pessah, I. N., Allen, P. D., Lopez, J. R. Nonspecific sarcolemmal cation channels are critical for the pathogenesis of malignant hyperthermia.

Low concentration of rapamycin inhibits hemangioma endothelial cell proliferation, migration, and vascular tumor formation in mice.

BACKGROUND: Vascular endothelial cell excessive proliferation is the main biological behavior of hemangioma. Rapamycin regulates the growth of endothelial cells by inhibiting mammalian target of rapamycin (mTOR). Thus hemangioma accompanied by excessive mTOR activation should be sensitive to rapamycin. We aimed to illustrate the effect of low-concentration rapamycin on hemangioma and provide a safe and effective drug therapy. METHODS: Mouse hemangioendothelioma endothelial cells and Nu/Nu mice were used. Rapamycin was applied in a concentration from 1 nM to 20 nM. WST-1 cell proliferation and transwell migration assays were used to analyze vascular tumor proliferation and migration in vitro. Xenograft mouse models were used to test vascular tumor growth in vivo. RESULTS: Low-concentration rapamycin (1 nM) inhibited hemangioendothelioma endothelial cell proliferation and migration in vitro and vascular tumor growth in vivo. The mechanism was decreased activation of the protein kinase B/mTOR/S6 ribosomal protein (S6) signaling pathway. CONCLUSIONS: Rapamycin used in vitro was analogous to low serum concentration rapamycin (7-16 nM) and also significantly inhibited the growth of hemangioma. These results demonstrate a low-toxic drug therapy for hemangioma and encourage continued development of rapamycin and its analogs for use in vascular tumor therapy.

A novel simple laser guidance puncture system for intracerebral hematoma.

OBJECTIVE: Accurate localization and real-time guidance technologies for cerebral hematomas are essential for minimally invasive procedures, including minimally invasive hematoma puncture and drainage, as well as neuroendoscopic-assisted hematoma removal. This study aims to evaluate the precision and safety of a self-developed laser-guided device in localizing and guiding hematoma punctures in minimally invasive surgery for intracerebral hemorrhage (ICH). METHODS: We present the components of the device and its operational procedures. Subsequently, surgeons with different titles conduct hematoma puncture experiments using the device on skull models, comparing it to freehand puncture methods and recording the offset distance from the puncture needle tip to the hematoma center. Additionally, we report the application of this device in 10 patients with ICH, assessing its accuracy and safety in comparison with a neuro-navigation system. RESULTS: In simulated puncture experiments, the accuracy of the laser-guided group surpasses that of the freehand puncture group, with a significant statistical difference observed between the two groups (P < 0.05). In the laser-guided group, there is no statistically significant difference in puncture accuracy among the surgeons (P > 0.05). In clinical experiments, no relevant surgical complications were observed. The offset distance for the laser-guided group was 0.61 ± 0.18 cm, while the neuro-navigation group was 0.48 ± 0.13 cm. There was no statistically significant difference between the two groups in terms of offset distance (P > 0.05). However, there was a significant difference in surgical duration (P < 0.05), with the former being 35.0 ± 10.5 minutes and the latter being 63.8 ± 10.5 minutes. CONCLUSION: The current study describes satisfactory results from both simulated experiments and clinical applications, achieved through the use of a novel laser-guided hematoma puncture device. Furthermore, owing to its portability, affordability, and simplicity, it holds significant importance in advancing surgical interventions for ICH, especially in underdeveloped regions.

Botulinum toxin A attenuates osteoarthritis development via inhibiting chondrocyte ferroptosis through SLC7Al1/GPX4 axis.

Osteoarthritis (OA) is a prevalent joint degenerative disease, resulting in a significant societal burden. However, there is currently a lack of effective treatment option available. Previous studies have suggested that Botulinum toxin A (BONT/A), a macromolecular protein extracted from Clostridium Botulinum, may improve the pain and joint function in OA patients, but the mechanism remains elusive. This study was to investigate the impact and potential mechanism of BONT/A on OA in vivo and in vitro experiment. LPS increased the levels of ROS, Fe2+and Fe3+, as well as decreased GSH levels, the ratio of GSH / GSSH and mitochondrial membrane potential. It also enhanced the degeneration of extracellular matrix (ECM) and altered the ferroptosis-related protein expression in chondrocytes. BONT/A rescued LPS-induced decrease in collagen type II (Collagen II) expression and increase in matrix metalloproteinase 13 (MMP13), mitigated LPS-induced cytotoxicity in chondrocytes, abolished the accumulation of ROS and iron, upregulated GSH and the ratio of GSH/ GSSH, improved mitochondrial function, and promoted SLC7A11/GPX4 anti-ferroptosis system activation. Additionally, intra-articular injection of BONT/A inhibited the degradation of cartilage in OA model rats. This chondroprotective effect of BONT/A was reversed by erastin (a classical ferroptosis agonist) and enhanced by liproxstatin-1 (a classic ferroptosis inhibitor). Our research confirms that BONT/A alleviates the OA development by inhibiting the ferroptosis of chondrocytes, which revealed to be a potential therapeutic mechanism for BONT/A treating the OA.

Integrated metabolic profiles and microbial communities to reveal the beneficial effect of red pitaya on early constipation.

Pitaya is a well-known fruit widely cultivated in tropical and subtropical tropical regions, and is characterized by its flesh colour into red, white, and yellow pitaya. Red pitaya has dark red flesh and is the preferred choice among consumers due to its superior taste compared to other varieties. Red pitaya has been known to cause diarrhoea, and studies have reported that pitaya does this by drawing moisture into the intestines, resulting in defecation. However, the exact mechanism of action is still unclear. In this study, mass spectrometry was employed to identify small molecular compounds in red pitaya powder, and a loperamide hydrochloride-induced early constipation mouse model was used to assess the efficacy of red pitaya. 16S rDNA and non-targeted metabolomics techniques were used to systematically reveal the regulatory characteristics of the intestinal flora and to identify the intestinal metabolites associated with constipation. The results showed that 44 novel small molecular compounds were identified from red pitaya powder, including a variety of phenolic acids and flavonoids. Pathological results showed that administration of red pitaya powder at a high dose (1000 mg kg-1) significantly ameliorated the abnormal expansion of intestinal goblet cells observed in the early stages of constipation. In addition, early constipation increased metabolites such as serotonin and 5-hydroxytryptophol, which were normalized following the ingestion of red pitaya powder. Furthermore, Erysipelatoclostridium, Parasutterella, and other abnormal gut microbiota associated with early constipation returned to healthy levels after the ingestion of red pitaya powder. Finally, significant correlations were observed between the expression of 33 different serum metabolites and the abundance of eight kinds of intestinal flora. Consequently, red pitaya holds potential as a safe food supplement for the prevention or amelioration of early-stage constipation.

Aurora kinase A regulates cancer-associated RNA aberrant splicing in breast cancer.

The contribution of oncogenes to tumor-associated RNA splicing and the relevant molecular mechanisms therein require further elaboration. Here, we show that oncogenic Aurora kinase A (AURKA) promotes breast cancer-related RNA aberrant splicing in a context-dependent manner. AURKA regulated pan-breast cancer-associated RNA splicing events including GOLGA4, RBM4 and UBQLN1. Aberrant splicing of GOLGA4 and RBM4 was closely related to breast cancer development. Mechanistically, AURKA interacted with the splicing factor YBX1 and promoted AURKA-YBX1 complex-mediated GOLGA4 exon inclusion. AURKA binding to the splicing factor hnRNPK promoted AURKA-hnRNPK complex-mediated RBM4 exon skipping. Analysis of clinical data identified an association between the AURKA-YBX1/hnRNPK complex and poor prognosis in breast cancer. Blocking AURKA nuclear translocation with small molecule drugs partially reversed the oncogenic splicing of RBM4 and GOLGA4 in breast cancer cells. In summary, oncogenic AURKA executes its function on modulating breast cancer-related RNA splicing, and nuclear AURKA is distinguished as a hopeful target in the case of treating breast cancer.

Mitochondrial DNA abnormalities and metabolic syndrome.

Metabolic syndrome (MetS) is a complex pathological condition that involves disrupted carbohydrate, protein, and fat metabolism in the human body, and is a major risk factor for several chronic diseases, including diabetes, cardiovascular disease, and cerebrovascular disease. While the exact pathogenesis of metabolic syndrome is not yet fully understood, there is increasing evidence linking mitochondrial dysfunction, which is closely related to the mitochondrial genome and mitochondrial dynamics, to the development of this condition. Recent advancements in genetic sequencing technologies have allowed for more accurate detection of mtDNA mutations and other mitochondrial abnormalities, leading to earlier diagnosis and intervention in patients with metabolic syndrome. Additionally, the identification of specific mechanisms by which reduced mtDNA copy number and gene mutations, as well as abnormalities in mtDNA-encoded proteins and mitochondrial dynamics, contribute to metabolic syndrome may promote the development of novel therapeutic targets and interventions, such as the restoration of mitochondrial function through the targeting of specific mitochondrial defects. Additionally, advancements in genetic sequencing technologies may allow for more accurate detection of mtDNA mutations and other mitochondrial abnormalities, leading to earlier diagnosis and intervention in patients with MetS. Therefore, strategies to promote the restoration of mitochondrial function by addressing these defects may offer new options for treating MetS. This review provides an overview of the research progress and significance of mitochondrial genome and mitochondrial dynamics in MetS.

Intestinal metabolites and the risk of autistic spectrum disorder: A two-sample Mendelian randomization study.

Background: Observational studies have reported a strong association between autistic spectrum disorder (ASD) and intestinal metabolites. However, it is unclear whether this correlation is causally or violated by confounding or backward causality. Therefore, this study explored the potential causal relationship between intestinal metabolites and dependent metabolites on ASD. Methods: We used a two-sample Mendelian random analysis and selected variants closely related to intestinal flora-dependent metabolites as instrumental variables. MR-Egger, inverse variance weighted (IVW), MR-PRESSO, maximum likelihood, and weighted median were performed to reveal their causal relationships. Ten metabolites were studied, which included trimethylamine-N-oxide, betaine, carnitine, choline, glutamate, kynurenine, phenylalanine, serotonin, tryptophan, and tyrosine. Sensitivity tests were also performed to evaluate the robustness of the MR study. Results: The IVW method revealed that serotonin may increase the ASD risk (OR 1.060, 95% CI: 1.006-1.118), while choline could decrease the ASD risk (OR 0.925, 95% CI: 0.868-0.988). However, no definite causality was observed between other intestinal metabolites (e.g., trimethylamine-N-oxide, betaine, and carnitine) with ASD. Additionally, neither the funnel plot nor the MR-Egger test showed horizontal pleiotropy, and the MR-PRESSO test found no outliers. Cochran's Q test showed no significant heterogeneity among the studies, suggesting the robustness of the study. Conclusion: Our study found potential causality from intestinal metabolites on ASD. Clinicians are encouraged to offer preventive measures to such populations.

Melatonin Attenuates Ropivacaine-Induced Apoptosis by Inhibiting Excessive Mitophagy Through the Parkin/PINK1 Pathway in PC12 and HT22 Cells.

Melatonin, as an endogenous circadian indoleamine secreted by the pineal gland, executes extensive biological functions, including antioxidant, anti-inflammatory, anti-tumor, and neuroprotective effects. Although melatonin has been reported to serve as a potential therapeutic against many nerve injury diseases, its effect on ropivacaine-induced neurotoxicity remains obscure. Our research aimed to explore the impact and mechanism of melatonin on ropivacaine-induced neurotoxicity. Our results showed that melatonin pretreatment protected the cell viability, morphology, and apoptosis of PC12 and HT22 cells, and it also improved ropivacaine-induced mitochondrial dysfunction and the activation of mitophagy. In addition, we found that autophagy activation with rapamycin significantly weakened the protective effect of melatonin against ropivacaine-induced apoptosis, whereas autophagy inhibition with 3-MA enhanced the effect of melatonin. We also detected the activation of Parkin and PINK1, a canonical mechanism for mitophagy regulation, and results shown that melatonin downregulated the expression of Parkin and PINK1, and upregulated Tomm20 and COXIV proteins, so that those results indicated that melatonin protected ropivacaine-induced apoptosis through suppressing excessive mitophagy by inhibiting the Parkin/PINK1 pathway. Melatonin may be a useful potential therapeutic agent against ropivacaine-induced neurotoxicity.

Impaired Orai1-mediated resting Ca2+ entry reduces the cytosolic [Ca2+] and sarcoplasmic reticulum Ca2+ loading in quiescent junctophilin 1 knock-out myotubes.

In the absence of store depletion, plasmalemmal Ca(2+) permeability in resting muscle is very low, and its contribution in the maintenance of Ca(2+) homeostasis at rest has not been studied in detail. Junctophilin 1 knock-out myotubes (JP1 KO) have a severe reduction in store-operated Ca(2+) entry, presumably caused by physical alteration of the sarcoplasmic reticulum (SR) and T-tubule junction, leading to disruption of the SR signal sent by Stim1 to activate Orai1. Using JP1 KO myotubes as a model, we assessed the contribution of the Orai1-mediated Ca(2+) entry pathway on overall Ca(2+) homeostasis at rest with no store depletion. JP1 KO myotubes have decreased Ca(2+) entry, [Ca(2+)](rest), and intracellular Ca(2+) content compared with WT myotubes and unlike WT myotubes, are refractory to BTP2, a Ca(2+) entry blocker. JP1 KO myotubes show down-regulation of Orai1 and Stim1 proteins, suggesting that this pathway may be important in the control of resting Ca(2+) homeostasis. WT myotubes stably transduced with Orai1(E190Q) had similar alterations in their resting Ca(2+) homeostasis as JP1 KO myotubes and were also unresponsive to BTP2. JP1 KO cells show decreased expression of TRPC1 and -3 but overexpress TRPC4 and -6; on the other hand, the TRPC expression profile in Orai1(E190Q) myotubes was comparable with WT. These data suggest that an important fraction of resting plasmalemmal Ca(2+) permeability is mediated by the Orai1 pathway, which contributes to the control of [Ca(2+)](rest) and resting Ca(2+) stores and that this pathway is defective in JP1 KO myotubes.

Mitophagy Disequilibrium, a Prominent Pathological Mechanism in Metabolic Heart Diseases.

With overall food intake among the general population as high as ever, metabolic syndrome (MetS) has become a global epidemic and is responsible for many serious life-threatening diseases, especially heart failure. In multiple metabolic disorders, maintaining a dynamic balance of mitochondrial number and function is necessary to prevent the overproduction of reactive oxygen species (ROS), which has been proved to be one of the important mechanisms of cardiomyocyte injury due to the mismatching of oxygen consumption and mitochondrial population and finally to heart failure. Mitophagy is a process that eliminates damaged or redundant mitochondria. It is mediated by a series of signaling molecules, including PINK, parkin, BINP3, FUNDC1, CTSD, Drp1, Rab9 and mTOR. Meanwhile, increasing evidence also showed that the interaction between ferroptosis and mitophagy interfered with mitochondrial homeostasis. This review will focus on these essential molecules and pathways of mitophagy and cell homeostasis affected by hypoxia and other stimuli in metabolic heart diseases.

Ropivacaine Induces Cell Cycle Arrest in the G0/G1 Phase and Apoptosis of PC12 Cells via Inhibiting Mitochondrial STAT3 Translocation.

STAT3 has neuroprotective effect via non-canonical activation and mitochondrial translocation, but its effect on ropivacaine-induced neurotoxicity remains unclear. Our previous study revealed that apoptosis was an important mechanism of ropivacaine-induced neurotoxicity; this study is to illustrate the relationship between STAT3 with ropivacaine-induced apoptosis. Those results showed that ropivacaine treatment decreased cell viability, induced cell cycle arrest in the G0/G1 phase, apoptosis, oxidative stress, and mitochondrial dysfunction in PC12 cells. Moreover, ropivacaine decreased the phosphorylated levels of STAT3 at Ser727 and downregulated the expression of STAT3 upstream gene IL-6. The mitochondrial translocation of STAT3 was also hindered by ropivacaine. To further illustrate the connection of STAT3 protein structure with ropivacaine, the autodock-vina was used to examine the interaction between STAT3 and ropivacaine, and the results showed that ropivacaine could bind to STAT3's proline site and other sites. In addition, the activator and inhibitor of mitoSTAT3 translocation were used to demonstrate it was involved in ropivacaine-induced apoptosis; the results showed that enhancing the mitochondrial STAT3 translocation could prevent ropivacaine-induced apoptosis. Finally, the expression of p-STAT3 and the levels of apoptosis in the spinal cord were also detected; the results were consistent with the cell experiment; ropivacaine decreased the expression of p-STAT3 protein and increased the levels of apoptosis in the spinal cord. We demonstrated that ropivacaine induced apoptosis by inhibiting the phosphorylation of STAT3 at Ser727 and the mitochondrial STAT3 translocation. This effect was reversed by the activation of the mitochondrial STAT3 translocation.