Involvement of regulated necrosis in blinding diseases: Focus on necroptosis and ferroptosis.

Besides apoptosis, necrosis can also occur in a highly regulated and genetically controlled manner, defined as regulated necrosis, which is characterized by a loss of cell membrane integrity and release of cytoplasmic content. Depending on the involvement of its signal pathway, regulated necrosis can be further classified as necroptosis, ferroptosis, pyroptosis and parthanatos. Numerous studies have demonstrated that regulated necrosis is involved in the pathogenesis of many diseases covering almost all organs including the brain, heart, liver, kidney, intestine, blood vessel, eye and skin, particularly myocardial infarction and stroke. Most recently, growing evidence suggests that multiple types of regulated necrosis contribute to the degeneration of retinal ganglion cells, retinal pigment epithelial cells or photoreceptor cells, which are the main pathologic features for glaucoma, age-related macular degeneration or retinitis pigmentosa, respectively. This review focuses on the involvement of necroptosis and ferroptosis in these blinding diseases.

Magnesium Lithospermate B Derived from Salvia miltiorrhiza Ameliorates Right Ventricle Remodeling in Pulmonary Hypertensive Rats via Inhibition of NOX/VPO1 Pathway.

Right ventricle (RV) remodeling is a major pathological feature in pulmonary arterial hypertension (PAH). Magnesium lithospermate B (MLB) is a compound isolated from the roots of Salvia miltiorrhiza and it possesses multiple pharmacological activities such as anti-inflammation and antioxidation. This study aims to investigate whether MLB is able to prevent RV remodeling in PAH and the underlying mechanisms. In vivo, SD rats were exposed to 10% O2 for 21 d to induce RV remodeling, which showed hypertrophic features (increases in the ratio of RV weight to tibia length, cellular size, and hypertrophic marker expression), accompanied by upregulation in expression of NADPH oxidases (NOX2 and NOX4) and vascular peroxidase 1 (VPO1), increases in hydrogen peroxide (H2O2) and hypochlorous acid (HOCl) production and elevation in phosphorylation levels of ERK; these changes were attenuated by treating rats with MLB. In vitro, the cultured H9c2 cells were exposed to 3% O2 for 24 h to induce hypertrophy, which showed hypertrophic features (increases in cellular size and hypertrophic marker expression). Administration of MLB or VAS2870 (a positive control for NOX inhibitor) could prevent cardiomyocyte hypertrophy concomitant with decreases in NOX (NOX2 and NOX4) and VPO1 expression, H2O2 and HOCl production, and ERK phosphorylation. Based on these observations, we conclude that MLB is able to prevent RV remodeling in hypoxic PAH rats through a mechanism involving a suppression of NOX/VPO1 pathway as well as ERK signaling pathway. MLB may possess the potential clinical value for PAH therapy.

Suppression of NADPH oxidase attenuates hypoxia-induced dysfunctions of endothelial progenitor cells.

NADPH oxidases (NOX) - derived reactive oxygen species (ROS) contribute to oxidative injury in hypoxia-induced pulmonary arterial hypertension. This study aims to evaluate the status of NOX in endothelial progenitor cells (EPCs) under hypoxic condition and to determine whether NOX inhibitors could attenuate hypoxia-induced dysfunctions of EPCs. EPCs were isolated from peripheral blood of SD rats and subjected to hypoxia (O2/N2/CO2, 1/94/5) for 24 h. The cells were collected for ß-galactosidase or Hoechst staining, or for functional analysis (migration, adhesion and tube formation). The NOX expression, activity and H2O2 content in EPCs were measured. The results showed that hypoxia treatment promoted EPC senescence and apoptosis, accompanied by the deteriorated functions of EPCs (the reduced abilities in adhesion, migration and tube formation), as well as an increase in NOX2 and NOX4 expression, NOX activity and H2O2 production, these phenomena were attenuated by NOX inhibitors. Furthermore, administration of catalase could also improve the functions of hypoxia-treated EPCs. Based on these observations, we conclude that NOX-derived ROS contributes to the dysfunctions of EPCs under hypoxic condition. Thus, suppression of NOX may provide a novel strategy to improve endothelial functions in hypoxia-relevant diseases.

Nuclear cardiac myosin light chain 2 modulates NADPH oxidase 2 expression in myocardium: a novel function beyond muscle contraction.

Recent studies demonstrated that NADPH oxidase 2 (NOX2) expression in myocardium after ischemia-reperfusion (IR) is significantly upregulated. However, the underlying mechanisms remain unknown. This study aims to determine if nuclear cardiac myosin light chain 2 (MYL2), a well-known regulatory subunit of myosin, functions as a transcription factor to promote NOX2 expression following myocardial IR in a phosphorylation-dependent manner. We examined the phosphorylation status of nuclear MYL2 (p-MYL2) in a rat model of myocardial IR (left main coronary artery subjected to 1 h ligation and 3 h reperfusion) injury, which showed IR injury and upregulated NOX2 expression as expected, accompanied by elevated H2O2 and nuclear p-MYL2 levels; these effects were attenuated by inhibition of myosin light chain kinase (MLCK). Next, we explored the functional relationship of nuclear p-MYL2 with NOX2 expression in H9c2 cell model of hypoxia-reoxygenation (HR) injury. In agreement with our in vivo findings, HR treatment increased apoptosis, NOX2 expression, nuclear p-MYL2 and H2O2 levels, and the increases were ameliorated by inhibition of MLCK or knockdown of MYL2. Finally, molecular biology techniques including co-immunoprecipitation (Co-IP), chromatin immunoprecipitation (ChIP), DNA pull-down and luciferase reporter gene assay were utilized to decipher the molecular mechanisms. We found that nuclear p-MYL2 binds to the consensus sequence AGCTCC in NOX2 gene promoter, interacts with RNA polymerase II and transcription factor IIB to form a transcription preinitiation complex, and thus activates NOX2 gene transcription. Our results demonstrate that nuclear MYL2 plays an important role in IR injury by transcriptionally upregulating NOX2 expression to enhance oxidative stress in a phosphorylation-dependent manner.

Salviaolate Protects Rat Brain from Ischemia-Reperfusion Injury through Inhibition of NADPH Oxidase.

Salviaolate is a group of depside salts isolated from Danshen (a traditional Chinese herbal medicine), with ≥ 85 % of magnesium lithospermate B. This study aims to investigate whether salviaolate is able to protect the rat brain from ischemia/reperfusion injury and the underlying mechanisms. Rats were subjected to 2 h of cerebral ischemia and 24 h of reperfusion to establish an ischemia/reperfusion injury model. The neuroprotective effects of salviaolate at different dosages were evaluated. A dosage (25 mg/kg) was chosen to explore the neuroprotective mechanisms of salviaolate. Neurological function, infarct volume, cellular apoptosis, nicotinamide adenine dinucleotide phosphate-oxidase activity, and H2O2 content were measured. In a nerve cell model of hypoxia/reoxygenation injury, magnesium lithospermate B was applied. Cellular apoptosis, lactate dehydrogenase, nicotinamide adenine dinucleotide phosphate-oxidase activity, and H2O2 content were examined. Ischemia/reperfusion treatment significantly increased the neurological deficit score, infarct volume, and cellular apoptosis accompanied by the elevated nicotinamide adenine dinucleotide phosphate-oxidase activity and H2O2 content in the rat brains. Administration of salviaolate reduced ischemia/reperfusion-induced cerebral injury in a dose-dependent manner concomitant with a decrease in nicotinamide adenine dinucleotide phosphate-oxidase activity and H2O2 production. Magnesium lithospermate B (20 mg/kg) and edaravone (6 mg/kg, the positive control) achieved the same beneficial effects as salviaolate did. In the cell experiments, the injury (indicated by apoptosis ratio and lactate dehydrogenase release), nicotinamide adenine dinucleotide phosphate-oxidase activity and H2O2 content were dramatically increased following hypoxia/reoxygenation, which were attenuated in the presence of magnesium lithospermate B (10(-5) M), VAS2870 (nicotinamide adenine dinucleotide phosphate-oxidase inhibitor), or edaravone (10(-5) M). The results suggest that salviaolate is able to protect the brain from ischemia/reperfusion oxidative injury, which is related to the inhibition of nicotinamide adenine dinucleotide phosphate-oxidase and a reduction of reactive oxygen species production.

Telaprevir Improves Memory and Cognition in Mice Suffering Ischemic Stroke via Targeting MALT1-Mediated Calcium Overload and Necroptosis.

Mucosa-associated lymphoid tissue lymphoma translocation protein 1 (MALT1) has been confirmed to contribute to brain injury in ischemic stroke via promoting excitotoxicity and necroptosis. Telaprevir, a hepatitis C virus protease inhibitor, is predicted to be a potential MALT1 inhibitor. Here, we showed that telaprevir protected against cerebral ischemic injury via inhibiting MALT1, thereby preventing glutamate receptor ionotropic NMDA 2B (GluN2B) activation, limiting calcium overload, and suppressing necroptosis. In ischemic stroke mice, telaprevir reduced infarct volume, improved the long-term survival rate, and enhanced sensorimotor, memory, and cognitive functions. In hypoxia-treated nerve cells, telaprevir decreased the intracellular calcium concentrations and reduced LDH release. Mechanistically, telaprevir inhibited MALT1 protease activity, thus decreasing the membrane protein level of GluN2B and its phosphorylation through reducing the level of STEP61. Moreover, telaprevir was able to inhibit the levels of necroptosis-associated proteins. According to these results, it can be concluded that telaprevir alleviates neuronal brain injury in stroke mice via restraining GluN2B activation and suppresses the receptor-interacting protein kinase 1 (RIPK1)/receptor-interacting protein kinase 3 (RIPK3)/mixed lineage kinase domain-like pseudokinase (MLKL) pathway through inhibiting MALT1. Thus, telaprevir might have a novel indication for treating patients with ischemic stroke.

BloodCaps: A capsule network based model for the multiclassification of human peripheral blood cells.

BACKGROUND AND OBJECTIVE: The classification of human peripheral blood cells yields significance in the detection of inflammation, infections and blood cell disorders such as leukemia. Limitations in traditional algorithms for blood cell classification and increased computational processing power have allowed machine learning methods to be utilized for this clinically prevalent task. METHODS: In the current work, we present BloodCaps, a capsule based model designed for the accurate multiclassification of a diverse and broad spectrum of blood cells. RESULTS: Implemented on a large-scale dataset of 8 categories of human peripheral blood cells, the proposed architecture achieved an overall accuracy of 99.3%, outperforming convolutional neural networks such as AlexNet(81.5%), VGG16(97.8%), ResNet-18(95.9%) and InceptionV3(98.4%). Furthermore, we devised three new datasets(low-resolution dataset, small dataset, and low-resolution small dataset) from the original dataset, and tested BloodCaps in comparison with AlexNet, VGG16, ResNet-18, and InceptionV3. To further validate the applicability of our proposed model, we tested BloodCaps on additional public datasets such as the All IDB2, BCCD, and Cell Vision datasets. Compared with the reported results, BloodCaps showed the best performance in all three scenarios. CONCLUSIONS: The proposed method proved superior in octal classification among all three datasets. We believe the proposed method represents a promising tool to improve the diagnostic performance of clinical blood examinations.

Vaginal microbiomes and ovarian cancer: a review.

The human microbiome, often termed as "the forgotten organ", is an aggregation of microorganisms and their genomes that forms a mutualistic complex with the host. Recent research has shown the symbiotic merits of a microbiome ecosystem and its crucial role in the hosts' physiological functions. Disruption of this symbiotic relationship is prone to cause a broad spectrum of ailments, including cancer. The compositional and environmental factors that tip the scales from beneficial co-existence to the development of malignancy is actively investigated. Herein we review the latest research in knowledge regarding the association between the vaginal microbiomes and oncogenesis, with a particular focus on ovarian carcinoma.

Diabetic retinopathy: Focus on NADPH oxidase and its potential as therapeutic target.

Diabetic retinopathy is a common complication of diabetes that affects the retina due to a sustained high blood sugar level. Recent studies have demonstrated that high glucose-driven oxidative stress plays an important role in the microvascular complications of retina in diabetes. Oxidative stress occurs due to the excess of reactive oxygen species, which causes oxidative damage to retina, leading to the leak of tiny blood vessels, or acts as signaling molecules to trigger neovascularization, resulting in new fragile vessels. NADPH oxidase (NOX) is a key enzymatic source of reactive oxygen species in the retina, and it is involved in the early as well as the advanced stage of diabetic retinopathy. To date, at least 7 NOX isoforms, including NOX1 to NOX5, dual oxidase1 and dual oxidase 2, have been identified. It has been shown that NOX isoforms exert different roles in the pathogenesis of diabetic retinopathy. Intervention of NOX by its inhibitors or modulators shows beneficial effect on improving the retinal functions in the models of diabetic retinopathy in vivo or in vitro. Thereby, NOX might be a potential target for the therapy of diabetic retinopathy. The present review focuses on the role of NOX, particularly the NOX isoforms, in promoting the development of diabetic retinopathy. In addition, NOX isoforms as potential targets for therapy of diabetic retinopathy are also discussed.

The deafness gene GSDME: its involvement in cell apoptosis, secondary necrosis, and cancers.

Gasdermin E (GSDME), also called DFNA5, is a member of the gasdermin family. GSDME is involved in the regulation of apoptosis and necrosis. The N-terminal domain of GSDME displays an apoptosis-inducing activity while the C-terminal domain may serve as an apoptosis-inhibiting regulator by shielding the N-terminal domain. Besides its function in the regulation of apoptosis, GSDME was recently reported to be a substrate of caspase-3 and cleavage of GSDME by caspase-3 into necrotic N-terminal fragment leads to the induction of secondary necrosis. GSDME was first identified as a deafness gene because its mutation was associated with a specific form of autosomal dominant progressive sensorineural hearing loss. Furthermore, GSDME has been considered a tumor suppressor implicated in several types of cancer. This mini-review summarized recent reports relevant to the functions of GSDME in the regulation of apoptosis and necrosis as well as its clinical relevance.

Mitochondrial E3 ubiquitin ligase 1 promotes brain injury by disturbing mitochondrial dynamics in a rat model of ischemic stroke.

Mitochondrial dysfunctions contribute to brain injury in ischemic stroke while disturbance of mitochondrial dynamics results in mitochondrial dysfunction. Mitochondrial E3 ubiquitin ligase 1 (Mul1) involves in regulation of mitochondrial fission and fusion. This study aims to explore whether Mul1 contributes to brain injury in ischemic stroke and the underlying mechanisms. First, a rat ischemic stroke model was established by middle cerebral artery occlusion (MCAO), which showed ischemic injuries (increase in neurological deficit score and infarct volume) and upregulation of Mul1 in brain tissues. Next, Mul1 siRNAs were injected intracerebroventricularly to knockdown Mul1 expression, which evidently attenuated brain injuries (decrease in neurological deficit score, infarct volume and caspase-3 activity), restored mitochondrial dynamics and functions (decreases in mitochondrial fission and cytochrome c release while increase in ATP production), and restored protein levels of dynamin-related protein 1 (Drp1, a mitochondrial fission protein) and mitofusin2 (Mfn2, a mitochondrial fusion protein) through suppressing their sumoylation and ubiquitination, respectively. Finally, PC12 cells were cultured under hypoxic condition to mimic the ischemic stroke. Consistently, knockdown of Mul1 significantly reduced hypoxic injuries (decrease in apoptosis and LDH release), restored protein levels of Drp1 and Mfn2, recovered mitochondrial dynamics and functions (decreases in mitochondrial fission, mitochondrial membrane potential, reactive oxygen species production and cytochrome c release while increase in ATP production). Based on these observations, we conclude that upregulation of Mul1 contributes to brain injury in ischemic stroke rats and disturbs mitochondrial dynamics through sumoylation of Drp1 and ubiquitination of Mfn2.

Natural compound methyl protodioscin protects rat brain from ischemia/reperfusion injury through regulation of Mul1/SOD2 pathway.

Methyl protodioscin (MPD) is reported to relieve angina pectoris and myocardial ischemia, and mitochondrial E3 ubiquitin ligase 1 (Mul1) plays a key role in maintaining mitochondrial functions. Bioinformatic analysis shows potential interactions between MPD and Mul1. This study aims to explore whether MPD could protect rat brain against ischemia/reperfusion (I/R) injury through regulation of Mul1/ superoxide dismutase 2 (SOD2) pathway. The SD rat brains were subjected to 2 h of ischemia following by 24 h of reperfusion, which showed I/R injury (increase in neurological deficit score and infarct volume), up-regulation of Mul1 and down regulation of SOD2, these phenomena were attenuated by MPD treatment (3 or 10 mg/kg, i.g.). Consistently, in cultured HT22 cells, hypoxia-reoxygenation (H/R) treatment induced cellular injury (apoptosis and LDH release) concomitant with up-regulation of Mul1 and down regulation of SOD2, these phenomena were blocked in the presence of MPD (5 µM). Knockdown of Mul1 could also decrease SOD2 protein levels in HT22 cells accompanied by alleviation of H/R injury (reduction of apoptosis and LDH release). In agreement with the change of SOD2, reactive oxygen species generation was increased in H/R-treated HT22 cells while decreased in the presence of MPD. Based on these observations, we conclude that upregulation of Mul1 in rat brain contributes to cerebral I/R injury via suppression of SOD2 and that MPD protects rat brain from I/R injury through a mechanism involving regulation of Mul1/SOD2 pathway.

Coordination between NADPH oxidase and vascular peroxidase 1 promotes dysfunctions of endothelial progenitor cells in hypoxia-induced pulmonary hypertensive rats.

Previous studies have demonstrated that NADPH oxidase (NOX)/vascular peroxidase (VPO1) pathway - mediated oxidative stress plays an important role in the pathogenesis of multiple cardiovascular diseases. This study aims to evaluate the correlation between NOX/VPO1 pathway and endothelial progenitor cells (EPCs) dysfunctions in hypoxia-induced pulmonary hypertension (PH). The rats were exposed to 10% hypoxia for 3 weeks to establish a PH model, which showed increases in right ventricle systolic pressure, right ventricular and pulmonary vascular remodeling, acceleration in apoptosis and impairment in functions of the peripheral blood derived - EPCs (the reduced abilities in adhesion, migration and tube formation), accompanied by up-regulation of NOX (NOX2 and NOX4) and VPO1. Next, normal EPCs were cultured under hypoxia to induce apoptosis in vitro. Consistent with the in vivo findings, hypoxia enhanced the apoptosis and dysfunctions of EPCs concomitant with an increase in NOX and VPO1 expression, hydrogen peroxide (H2O2) and hypochlorous acid (HOCl) production; these phenomena were attenuated by NOX2 or NOX4 siRNA. Knockdown of VPO1 showed similar results to that of NOX siRNA except no effect on NOX expression and H2O2 production. Based on these observations, we conclude that NOX/VPO1 pathway-derived reactive oxygen species promote the oxidative injury and dysfunctions of EPCs in PH, which may contribute to endothelial dysfunctions in PH.

Combination of Emricasan with Ponatinib Synergistically Reduces Ischemia/Reperfusion Injury in Rat Brain Through Simultaneous Prevention of Apoptosis and Necroptosis.

Apoptosis and receptor-interacting protein kinase 1/3(RIPK1/3)-mediated necroptosis contribute to the cerebral ischemia/reperfusion (I/R) injury. Emricasan is an inhibitor of caspases in clinical trials for liver diseases while ponatinib could be a potential inhibitor for RIPK1/3. This study aims to investigate the effect of emricasan and/or ponatinib on cerebral I/R injury and the underlying mechanisms. Firstly, we evaluated the status of apoptosis and necroposis in a rat model of cerebral I/R under different conditions, which showed noticeable apoptosis and necroptosis under condition of 2-h ischemia and 24-h reperfusion; next, the preventive or therapeutic effect of emricasan or ponatinib on cerebral I/R injury was tested. Administration of emricasan or ponatinib either before or after ischemia could decrease the neurological deficit score and infarct volume; finally, the combined therapeutic effect of emricasan with ponatinib on I/R injury was examined. Combined application of emricasan and ponatinib could further decrease the I/R injury compared to single application. Emricasan decreased the activities of capase-8/-3 in the I/R-treated brain but not the protein levels of necroptosis-relevant proteins: RIPK1, RIPK3, and mixed lineage kinase domain-like (MLKL), whereas ponatinib suppressed the expressions of these proteins but not the activities of capase-8/-3. Combination of emricasan with ponatinib could suppress both capase-8/-3 and necroptosis-relevant proteins. Based on these observations, we conclude that combination of emricasan with ponatinib could synergistically reduce I/R injury in rat brain through simultaneous prevention of apoptosis and necroptosis. Our findings might lay a basis on extension of the clinical indications for emricasan and ponatinib in treating ischemic stroke.

Atorvastatin exerts inhibitory effect on endothelial senescence in hyperlipidemic rats through a mechanism involving down-regulation of miR-21-5p/203a-3p.

Statins are reported to exert benefits on endothelial function through a mechanism involving in prevention of endothelial senescence. This study aims to explore whether atorvastatin exerts inhibitory effect on endothelial senescence in hyperlipidemic rats or ox-LDL-treated HUVECs through a mechanism involving suppress of miR-21-5p/203a-3p expression and their downstream pathway. The rats were fed with high-fat diet to establish a hyperlipidemic model, which showed an increase in plasma lipids and endothelial senescence, accompanied by the elevation in plasma levels of miR-21-5p/203a-3p, down-regulation of Drp1 and up-regulation of p53 in the aorta of hyperlipidemic rats; these phenomena were reversed by atorvastatin. Next, HUVECs were incubated with ox-LDL to establish a senescent model in vitro. Consistent with the finding in vivo, atorvastatin treatment decreased the level of miR-21-5p and miR-203a-3p in the ox-LDL-treated HUVECs, restored Drp1 expression and mitochondrial function, as well as suppressed p53 and p16 expression and endothelial senescence. Based on these observations, we conclude that atorvastatin exerts inhibitory effect on endothelial senescence in hyperlipidemic rats through a mechanism involving down-regulation of miR-21-5p/203a-3p, which leads to the restoration of Drp1 level and recovery of mitochondrial function. Our findings highlight a novel non-lipid effect for atorvastatin besides its function in modulation of lipids.

NADPH oxidase: its potential role in promotion of pulmonary arterial hypertension.

NADPH oxidases (NOXs) are a group of enzymes for superoxide anion (O2·- ) generation through transferring electrons from NADPH to molecular oxygen, which is rapidly converted into hydrogen peroxide (H2O2). There are seven members in NOX family, including NOX1 to NOX5, dual oxidase1, and dual oxidase 2. Recent studies have demonstrated that NOX subtypes may have different functions in different types of pulmonary arterial hypertension (PAH). The NOX-derived reactive oxygen species (ROS) are key factors that are involved in promoting the processes of pulmonary vascular remodeling, such as endothelial dysfunction, proliferation of pulmonary arterial smooth muscle cells (PASMCs), and cellular trans-differentiation, which are the basic pathologic characteristics of PAH. Inhibition of NOX shows beneficial effect on prevention of PAH development. Thus, NOX might be a potential target for PAH therapy. The main purpose of this review is to summarize recent findings on the role of NOX, particularly the NOX subtypes, in promotion of PAH development and to list recent progress regarding the NOX-based intervention for PAH.

miR-21-5p/203a-3p promote ox-LDL-induced endothelial cell senescence through down-regulation of mitochondrial fission protein Drp1.

This study aims to identify both endothelia-specific/enriched and senescence-associated miRNAs as well as their functions. The rats were fed on high-fat diet to establish a hyperlipidemic model, which showed an increase in plasma lipids and acceleration in endothelial senescence and endothelial dysfunction, accompanied by alterations in 7 endothelia-specific/enriched and senescence-associated miRNAs. Among the 7 selected miRNAs, miR-21-5p and miR-203a-3p were significantly up-regulated in a human umbilical vein endothelial cells (HUVECs) senescent model induced by ox-LDL, consistent with their changes in the hyperlipidemic rats. After performing the bioinformatic analysis, dynamin-related protein 1 (Drp1) was predicted to be a potential target for both miR-21-5p and miR-203a-3p. In ox-LDL-induced senescent HUVECs, Drp1 was significantly down-regulated, concomitant with mitochondrial dysfunctions and the activation of AMPK-p53/p16 pathway, while these phenomena were attenuated by miR-21-5p or miR-203a-3p inhibitor. Luciferase reporter gene assay confirmed a direct interaction between miR-21-5p and Drp1 but not between miR-203a-3p and Drp1. Based on these observations, we conclude that miR-21-5p/203a-3p promote ox-LDL-induced endothelial senescence through down-regulation of Drp1 in a direct or indirect way. Our findings highlight the plasma levels of miR-21-5p/203a-3p may serve as novel biomarkers to evaluate the degree of endothelial senescence in hyperlipidemia.

Non-muscle myosin light chain promotes endothelial progenitor cells senescence and dysfunction in pulmonary hypertensive rats through up-regulation of NADPH oxidase.

Non-muscle myosin regulatory light chain (nmMLC20) is reported to exert transcriptional function in regulation of gene expression, and NADPH oxidase (NOX)-derived reactive oxygen species contribute to vascular remodeling of pulmonary artery hypertension (PAH). This study aims to determine if nmMLC20 can promote endothelial progenitor cells (EPCs) senescence and dysfunction through up-regulation of NOX in PAH rats. The rats were exposed to10% hypoxia for 3 weeks to establish a PAH model, which showed an increase in right ventricle systolic pressure, right ventricular and pulmonary vascular remodeling, and the accelerated senescence and impaired functions in EPCs, accompanied by an increase in Rho-kinase (ROCK) and NOX activities, p-nmMLC20 level, NOX expression and H2O2 content; these phenomena were reversed by fasudil, a selective inhibitor of ROCK. Next, normal EPCs were cultured under hypoxia to induce senescence in vitro. Consistent with the in vivo findings, hypoxia increased the senescence and dysfunction of EPCs concomitant with an increase in ROCK and NOX activities, p-nmMLC20 level, NOX expression and H2O2 content; these phenomena were reversed by fasudil. Knockdown of nmMLC20 showed similar results to that of fasudil except no effect on ROCK activity. Based on these observations, we conclude that nmMLC20 could promote the senescence and dysfunctions of EPCs in PAH through up-regulation of NOX in a phosphorylation-dependent manner.

Beneficial effect of magnesium lithospermate B on cerebral ischemia-reperfusion injury in rats involves the regulation of miR-107/glutamate transporter 1 pathway.

Recent studies uncovered that glutamate accumulation following cerebral ischemia-reperfusion (I/R) was related to the dysfunction of miR-107/glutamate transporter-1(GLT-1) pathway and magnesium lithospermate B (MLB) possesses the pharmacological activity of anti-excitotoxicity. This study aims to explore whether MLB is able to protect rat brain from excitatory neurotoxicity during I/R by modulating miR-107/GLT-1 pathway. Rats were subjected to 2h of cerebral ischemia following by 24h of reperfusion to establish an I/R injury model, which showed an increase in neurological deficit score, infarct volume and cellular apoptosis concomitant with glutamate accumulation, miR-107 elevation and GLT-1 down-regulation. Administration of MLB reduced I/R-induced cerebral injury accompanied by a reverse in glutamate accumulation, miR-107 and GLT-1 expression. Next, we examined the association of MLB with miR-107/GLT-1 pathway in a nerve cell hypoxia/reoxygenation (H/R) injury model. H/R treatment increased the nerve cells apoptosis concomitant with glutamate accumulation and miR-107 elevation, and suppressed GLT-1 expression, mimicking our in vivo findings. All these effects were reversed in the presence of MLB, confirming a strong correlation between MLB and miR-107/GLT-1 pathway. Based on these observations, we conclude that MLB is able to protect the rat brain from excitatory neurotoxicity during I/R through the regulation of miR-107/GLT-1 pathway.

Inhibition of myosin light chain kinase reduces NADPH oxidase-mediated oxidative injury in rat brain following cerebral ischemia/reperfusion.

Previous studies have demonstrated that nicotinamide adenine dinucleotide phosphate (NADPH) oxidase (NOX)-mediated oxidative stress plays a key role in brain injury following cerebral ischemia/reperfusion (I/R) and myosin regulatory light chain kinase (MLCK) has been reported to be involved in NOX activation in lung endothelium. This study was performed to explore the correlation between MLCK and NOX following cerebral I/R and the underlying mechanisms. Sprague-Dawley (SD) rats were subjected to 2 h middle cerebral artery occlusion and 24 h reperfusion to establish a model of focal cerebral I/R injury. At the end of experiments, neurological function, infarct volume, cellular apoptosis, activities of MLCK and NOX, messenger RNA (mRNA) and protein expression of NOX (NOX1-NOX4), phosphorylation level of myosin regulatory light chain (MLC20) and hydrogen peroxide (H2O2) level were determined. The results showed that I/R treatment led to increase in neurological deficit score, infarct volume and cellular apoptosis, accompanied by the elevated activities of MLCK and NOX, expressions of NOX2 and NOX4, levels of phosphorylation MLC20 and H2O2, these effects were attenuated by MLCK specific inhibitor (ML-7). NOX inhibitors (diphenylene iodonium (DPI) or apocynin) were able to achieve similar results to that of ML-7 except no effect on MLCK activity and MLC20 phosphorylation. These results suggest that activation of MLCK contributes to cerebral I/R oxidative injury through upregulation of NOX2 and NOX4 expression, which is involved in phosphorylation of MLC20.