Transferase-mediated dUTP Nick-end Labeling Staining Research Articles

Polyoxometalate SbW9 regulates proliferation and apoptosis of NSCLC cells via PTEN-dependent AKT signaling pathway.

To explore the influence of polyoxometalate SbW9 on proliferation and apoptosis of non-small cell lung cancer (NSCLC) cells and its mechanism. NSCLC cell lines A549 and PC9 were treated with 50 μM polyoxometalate. Then, the proliferation of NSCLC cells was detected via 2,3-bis(2-methoxy-4-nitro-5-sulfophenyl)-5-[(phenylamino)carbonyl]-2H-t tetrazolium hydroxide (XTT) assay and colony formation assay; the apoptosis of NSCLC cells was detected via flow cytometry and terminal deoxynucleotidyl transferase-mediated dUTP nick end labeling (TUNEL); and the expression of apoptosis-related proteins, B-cell lymphoma-2 (Bcl-2), and Bcl-2 associated X protein (Bax), was detected via Western blotting. Moreover, the protein expression levels of phosphatase and tensin homolog deleted on chromosome ten (PTEN), phosphorylated-protein kinase B (P-AKT) and total AKT (T-AKT) were detected via Western blotting. The polyoxometalate inhibited the proliferation of A549 and PC9 cells in a concentration-dependent manner (5-100 μM) (p<0.05), and it (50 μM) also inhibited the proliferation of both cells in a time-dependent manner (0-72 h) (p<0.05). The results of colony formation assay revealed that the polyoxometalate (50 μM) could significantly inhibit the colony formation of A549 and PC9 cells (p<0.05). The results of flow cytometry and TUNEL staining showed that the polyoxometalate (50 μM) significantly induced the apoptosis of A549 and PC9 cells (p<0.05). According to further studies, the polyoxometalate (50 μM) inhibited the expression of anti-apoptotic gene Bcl-2 and promoted the expression of pro-apoptotic gene Bax. Besides, the Western blotting results manifested that the polyoxometalate could activate the expression of PTEN and inhibit the phosphorylation of downstream AKT (p<0.05). The polyoxometalate can activate the expression of PTEN to inhibit the phosphorylation of AKT, ultimately inhibiting the proliferation and inducing the apoptosis of NSCLC cells. Therefore, the polyoxometalate is expected to become a novel drug for the clinical treatment of NSCLC.

Atorvastatin improves the cardiac function of rats after acute myocardial infarction through ERK1/2 pathway.

To study the regulatory effect of atorvastatin (ATV) on the extracellular signal-regulated kinase (ERK) 1/2 pathway and explore its effect on acute myocardial infarction (AMI) rats. The rat model of AMI was established, and the model rats were randomly divided into AMI group and ATV-AMI group, and Sham group was also set up. At 4 weeks after successful modeling, the cardiac function indexes of Sprague-Dawley (SD) rats were detected via magnetic resonance imaging (MRI) and echocardiography (ECG). After the rats were executed, the left ventricular weight index (LVWI) was measured, and the myocardial damage was detected via hematoxylin-eosin (HE) staining and terminal deoxynucleotidyl transferase-mediated dUTP nick end labeling (TUNEL) staining. Moreover, the messenger ribonucleic acid (mRNA) expressions of collagen I and collagen III in myocardial tissues were detected via Real Time-Polymerase Chain Reaction (PCR), and the expressions of ERK1/2 pathway-related proteins in myocardial tissues were detected via Western blotting. After administration of ATV for AMI, the fractional shortening (FS%) and ejection fraction (EF%) were significantly restored. Compared with that in ATV-AMI group, LVWI was significantly increased in AMI group (p<0.05), indicating that ATV could improve the cardiac function after AMI. The results of HE staining and TUNEL staining showed that ATV-AMI group had slighter myocardial damage and significantly lower apoptosis rate than AMI group, indicating that ATV could reverse AMI through the ERK1/2 pathway. Besides, the mRNA expressions of collagen I and collagen III were higher in AMI group and ATV-AMI group than those in Sham group (p<0.05), while they were significantly lower in ATV-AMI group than those in AMI group (p<0.05). The expressions of ERK1/2 pathway-related proteins were also higher in AMI group and ATV-AMI group than those in Sham group (p<0.05). ATV can significantly improve the cardiac function of SD rats after AMI, whose mechanism is related to the expression of the ERK1/2 pathway.

Effect of miR-26a targeting GSK-3β/β-catenin signaling pathway on myocardial apoptosis in rats with myocardial ischemia-reperfusion.

The aim of this study was to evaluate the effect of micro ribonucleic acid (miR)-26a on myocardial ischemia-reperfusion (I/R) injury in rats and to explore its potential mechanism. Our findings might help to provide references for clinical prevention and treatment of myocardial I/R. A total of 60 male Sprague-Dawley (SD) rats were randomly divided into three groups using a random number table, including: Control group (n=20), I/R group (n=20) and I/R + miR-26a siRNA group (n=20). I/R model was established via recanalization after ligation of left anterior descending coronary artery (LAD). The model of miR-26a knockdown was established in rats of I/R + miR-26a siRNA group via tail intravenous injection of miR-26a siRNA. Ejection fraction (EF%) and fractional shortening (FS%) of rats in each group were detected via echocardiography. The infarction area of each group was detected via 2,3,5-triphenyltetrazolium chloride (TTC) assay. Subsequently, morphological changes in myocardial cells of each group were detected via hematoxylin-eosin (H&E) staining. Myocardial apoptosis level was measured via terminal deoxynucleotidyl transferase-mediated dUTP nick end labeling (TUNEL) assay. At the same time, the expression levels of pro-apoptotic proteins Bcl-2 associated X protein (Bax) and cleaved (C)-caspase3 in myocardial tissues of the three groups were determined using Western blotting. Finally, the effects of miR-26a knockdown on the expressions of glycogen synthase kinase (GSK)-3β/β-catenin signaling pathway-related proteins were detected via Western blotting and immunohistochemistry. The expression of miR-26a in myocardial tissues of I/R group increased significantly when compared with that in Control group (p<0.05). Knockdown of miR-26a significantly improved cardiac insufficiency caused by I/R, which also obviously increased both EF% and FS% in rats (p<0.05). In addition, knockdown of miR-26a significantly inhibited myocardial infarction caused by I/R injury, and reduced infarction area from (43.08±2.43) to (21.54±1.82) (p<0.05). The results of H&E staining revealed that in I/R + miR-26a siRNA group, myofilaments were arranged more orderly, the degree of degradation and necrosis was significantly lower, and cellular edema was significantly alleviated when compared with I/R group. Subsequent TUNEL staining demonstrated that rats in I/R + miR-26a siRNA group showed a remarkably lower level of myocardial apoptosis than I/R group (p<0.05). Meanwhile, the protein expression levels of Bax and C-caspase3 were remarkably declined in I/R + miR-26a siRNA group (p<0.05). Furthermore, the results of Western blotting showed that miR-26a siRNA could significantly reverse the inhibition of GSK-3β/β-catenin signaling pathway induced by I/R injury (p<0.05). Knockdown of miR-26a could significantly improve I/R-induced myocardial injury and promote cardiac function in rats. The possible underlying mechanism might be related to targeted regulation of miR-26a on GSK-3β/β-catenin signaling pathway. Therefore, miR-26a was expected to be a new therapeutic target for myocardial I/R injury.

Nicorandil prevents doxorubicin-induced human umbilical vein endothelial cell apoptosis

Nicorandil is an adenosine triphosphate-sensitive potassium channel opener with additional antioxidant properties. Doxorubicin (DOX) is an anticancer drug that exerts oxidation-mediated adverse cardiovascular effects. This study examined the effects of nicorandil on DOX-induced cytotoxicity in human umbilical vein endothelial cells (HUVECs) and underlying intracellular signaling mechanisms. Cultured HUVECs were pretreated with nicorandil (0.1, 0.3, 1, 3, and 10 μM) for 12 h and then treated with DOX (1 μM) for 24 h. Cell viability and cytotoxicity were measured using 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide and lactate dehydrogenase assays, respectively. Cell apoptosis was examined using a caspase-3 activity assay, and DNA fragmentation was detected through TUNEL (terminal deoxynucleotidyl transferase-mediated dUTP nick end labeling) staining. Western blot analysis was conducted to determine the related protein expression. DOX markedly increased reactive oxygen species production, p53 expression, caspase-3 activity, cleaved caspase-3 levels, and TUNEL-positive cell numbers but reduced Bcl-2 expression and intracellular antioxidant enzyme levels; these effects were effectively antagonized through nicorandil (3 μM, 12 h) pretreatment, which resulted in HUVECs being protected from DOX-induced apoptosis. Activating transcription factor 3 (ATF3), a stress-induced transcription factor, was induced by nicorandil (3 μM). Furthermore, nicorandil (3 μM) enhanced nuclear factor erythroid 2–related factor 2 (Nrf2) translocation and heme oxygenase-1 (HO-1) expression. ATF3 short interfering RNA significantly attenuated nicorandil-mediated Nrf2 translocation, HO-1 expression, and inhibitory effects on DOX-stimulated reactive oxygen species production and cell apoptosis. In summary, nicorandil may protect HUVECs from DOX-induced apoptosis, in part through ATF3-mediated Nrf2/HO-1 signaling pathways, which potentially protect the vessels from severe DOX toxicity.

Neuronal Ca2+ -dependent activator protein 1 (NCDAP1) induces neuronal cell death by activating p53 pathway following traumatic brain injury.

Overactivation of N-methyl-d-aspartate glutamate receptors (NMDARs) after traumatic brain injury (TBI) contributes to excitotoxic cell death. The hyperactivation of NMDARs results in toxic levels of intracellular Ca2+ and in the activation of p53-mediated apoptosis pathway. Neuronal Ca2+ -dependent activator protein 1 (NCDAP1) was identified as an epileptogenic gene of unknown function in our laboratory. In this study, we investigated the expression and cellular localization of NCDAP1 in rat models of fluid percussion-induced TBI. NCDAP1 expression increased in the ipsilateral cortex and hippocampus adjacent to the lesion of the TBI rats compared with that in the sham-operated controls. In addition, NCDAP1 was co-expressed with neuronal marker (NeuN), and the results of terminal deoxynucleotidyl transferase-mediated dUTP nick-end labeling (TUNEL) staining suggest that NCDAP1 is involved in neuronal apoptosis that occurs after brain injury. In addition, the expression levels of p53, Bax, and active caspase-3 correlated with those of NCDAP1. To further investigate the function of NCDAP1, primary cultured neurons were employed to establish an apoptosis model. The expression of NCDAP1 was induced by NMDA-induced Ca2+ influx, and the knockdown of NCDAP1 by siRNA decreased apoptosis caused by treatment with NMDA. Silencing of NCDAP1 also reduced p53 expression, whereas the over-expression of NCDAP1 induced cell death and up-regulated the expression of p53. The inhibition of p53 with pifithrin alpha or siRNA counteracted the effects of NCDAP1. Based on our data, we suggest that NCDAP1 plays an important role in p53-mediated neuronal apoptosis following TBI.

The neuroprotection of hypoxic adipose tissue-derived mesenchymal stem cells in experimental traumatic brain injury

Traumatic brain injury is one of the leading causes of mortality and morbidity worldwide. At present there is no effective treatment. Previous studies have demonstrated that topical application of adipose tissue-derived mesenchymal stem cells can improve functional recovery in experimental traumatic brain injury. In this study, we evaluated whether hypoxic preconditioned mesenchymal stem cells could enhance the recovery from traumatic brain injury. Traumatic brain injury was induced with an electromagnetically controlled cortical impact device. Two million mesenchymal stem cells derived from the adipose tissue of transgenic green fluorescent protein Sprague-Dawley rats were cultured under either hypoxic (2.5% O2 for 18 hours) (N = 30) or normoxic (18% O2) (N = 30) conditions, then topically applied to the exposed cerebral cortex within 1 hour after traumatic brain injury. A thin layer of fibrin was used to fix the cells in position. No treatment was given to the animals with traumatic brain injury (N = 30). Animals that underwent craniectomy without traumatic brain injury were treated as the sham group (N = 15). Neurological functions were evaluated with water maze, Roto-rod and gait analysis. Animals were sacrificed at days 3, 7, and 14 for microscopic examinations and real-time polymerase chain reaction analysis. The rats treated with hypoxic mesenchymal stem cells showed the greatest improvement in neurological function recovery. More green fluorescent protein-positive cells were found in the injured brain parenchyma treated with hypoxic mesenchymal stem cells that co-expressed glial fibrillary acidic protein, Nestin, and NeuN. Moreover, there was early astrocytosis triggered by the infiltration of more glial fibrillary acidic protein-positive cells and microgliosis was suppressed with fewer ionized calcium binding adapter molecule 1-positive cells in the penumbra region of hypoxic mesenchymal stem cells group at day 3. Compared with normoxic mesenchymal stem cells and traumatic brain injury only groups, there was significantly (p < 0.05) less neuronal death in both the hippocampus and penumbral regions in sections treated with hypoxic mesenchymal stem cells as determined by Cresyl violet and terminal deoxynucleotidyl transferase-mediated dUTP nick end-labeling staining respectively. The expression of pro-inflammatory genes (interleukin 6, interleukin 1a, interleukin 1b, tumor necrosis factor α) was upregulated and apoptotic gene (Caspase-3) expression was suppressed at day 3. Anti-inflammatory (interleukin 10) and anti-apoptotic (BCL2 associated agonist of cell death) gene expression was upregulated at days 7 and 14. Our study showed that a hypoxic precondition enhanced the beneficial effects of mesenchymal stem cells on neurological recovery after traumatic brain injury.

Effects of miR-21 on hypertensive rats through PTEN/PI3K/Akt/mTOR signaling pathway.

The aim of this study was to investigate the effects of micro-ribonucleic acid (miR)-21 on hypertensive rats through the phosphatase and tensin homolog deleted on chromosome ten (PTEN)/phosphatidylinositol 3-kinase (PI3K)/protein kinase B (Akt)/mammalian target of rapamycin (mTOR) signaling pathway. A total of 10 spontaneously hypertensive rats (SHRs) were selected as the model group. Meanwhile, 10 rats with the same age were enrolled in the normal control group. Real Time-fluorescence quantitative Polymerase Chain Reaction (qRT-PCR) was performed to detect the mRNA level of miR-21 in rats of the SHR model group and control group. The tail arterial diastolic pressure of rats in the awake and resting state was measured in both groups, respectively. Pathological sections were prepared to evaluate pathological changes in myocardial tissues. Subsequently, myocardial cells were isolated, cultured and transfected with miR-21 mimics and miR-21 inhibitor, respectively. Transfection efficiency was verified using fluorescence quantitative PCR. Terminal deoxynucleotidyl transferase-mediated dUTP nick end labeling (TUNEL) assay was utilized to determine the apoptosis level of myocardial cells. Furthermore, the expression levels of the signaling pathway-related proteins were detected via Western blotting assay. Fluorescence quantitative PCR results revealed that the expression level of miR-21 was significantly higher in the SHR model group (p<0.05). The diastolic pressure increased markedly in the SHR model group when compared with that in the control group (p<0.05). Subsequent hematoxylin and eosin (HE) staining indicated apparent myocardial tissue injury in the SHR model group (p<0.05). After transfection, the results showed that miR-21 inhibitor could effectively down-regulate the expression level of miR-21 in myocardial cells (p<0.05). Meanwhile, TUNEL staining revealed that the number of apoptotic cells in the miR-21 inhibitor group was remarkably higher than that of the other two groups (p<0.05). In addition, Western blotting results manifested that the protein expression levels of PTEN, PI3K, Akt and mTOR were significantly lower in the miR-21 mimics group (p<0.05), whereas was remarkably higher in the miR-21 inhibitor group (p<0.05). MiR-21 is involved in regulating the pathological symptoms and myocardial cell apoptosis in hypertensive rats through the PTEN/PI3K/Akt/mTOR signaling pathway.

TIGAR suppresses seizures induced by kainic acid through inhibiting oxidative stress and neuronal apoptosis

TP53-induced glycolysis and apoptosis regulator (TIGAR) activates the pentose phosphate pathway (PPP), which feeds reduced nicotinamide adenine dinucleotide phosphate (NADPH) to the antioxidant glutathione pathway. Oxidative stress-induced neuronal apoptosis is the pathological basis of several neurological disorders, including epilepsy. To determine the potential anti-epileptic action TIGAR in a rodent kainic acid (KA)-induced seizure model.Seizures were induced by the intra-cerebroventricular injection of KA, followed by injection of empty or TIGAR-expressing lentiviral vectors. Immunofluorescence was used to detect the localization of TIGAR in the cortices and hippocampi, and the expression levels of relevant proteins were determined by Western blotting. Oxidative stress-related markers were detected using commercially available kits. Neuronal apoptosis was detected by terminal deoxynucleotidyl transferase-mediated dUTP nick end-labeling (TUNEL) staining. TIGAR were mainly expressed in the neurons and rarely located in the astrocytes, and increased in the cortices and hippocampi of KA-treated rats in a time-dependent manner. Lentivirus-mediated TIGAR overexpression significantly decreased the oxidative stress and neuronal apoptosis induced by KA, resulting in prolonged seizure latency and lower Racine scores. Our findings indicate that TIGAR has anti-epileptic, anti-oxidant and anti-apoptotic effects, and is therefore a promising therapeutictarget for epilepsy.

Curcumin Inhibits the PERK-eIF2α-CHOP Pathway through Promoting SIRT1 Expression in Oxidative Stress-induced Rat Chondrocytes and Ameliorates Osteoarthritis Progression in a Rat Model.

Oxidative stress plays a crucial role in the occurrence and development of osteoarthritis (OA) through the activation of endoplasmic reticulum (ER) stress. Curcumin is a polyphenolic compound with significant antioxidant and anti-inflammatory activity among various diseases. To elucidate the role of curcumin in oxidative stress-induced chondrocyte apoptosis, this study investigated the effect of curcumin on ER stress-related apoptosis and its potential mechanism in oxidative stress-induced rat chondrocytes. The results of flow cytometry and terminal deoxynucleotidyl transferase-mediated dUTP nick-end labeling (TUNEL) staining showed that curcumin can significantly attenuate ER stress-associated apoptosis. Curcumin inhibited the expression of cleaved caspase3, cleaved poly (ADP-ribose) polymerase (PARP), C/EBP homologous protein (CHOP), and glucose-regulated protein78 (GRP78) and upregulated the chondroprotective protein Bcl2 in TBHP-treated chondrocytes. In addition, curcumin promoted the expression of silent information regulator factor 2-related enzyme 1 (SIRT1) and suppressed the expression of activating transcription factor 4 (ATF4), the ratio of p-PERK/PERK, p-eIF2α/eIF2α. Our anterior cruciate ligament transection (ACLT) rat OA model research demonstrated that curcumin (50 mg/kg and 150 mg/kg) ameliorated the degeneration of articular cartilage and inhibited chondrocyte apoptosis in ACLT rats in a dose-dependent manner. By applying immunohistochemical analysis, we found that curcumin enhanced the expression of SIRT1 and inhibited the expression of CHOP and cleaved caspase3 in ACLT rats. Taken together, our present findings firstly indicate that curcumin could inhibit the PERK-eIF2α-CHOP axis of the ER stress response through the activation of SIRT1 in tert-Butyl hydroperoxide- (TBHP-) treated rat chondrocytes and ameliorated osteoarthritis development in vivo.

Anticonvulsant and anti-apoptosis effects of salvianolic acid B on pentylenetetrazole-kindled rats via AKT/CREB/BDNF signaling

Neuronal apoptosis is a regulated intrinsic cell mechanism and common pathological phenomenon after seizures, which involves the protein kinase B/cAMP response element binding protein / brain derived neurotrophic factor (AKT/CREB/ BDNF) signaling pathway. In this study, we aimed to identify the effects of salvianolic acid B (Sal B), a major water-soluble component of the Chinese herb, Danshen, on rats in which seizures had been induced by pentylenetetrazole (PTZ) and the underlying molecular mechanisms mediating these effects. For this, 60 adult male Sprague-Dawley rats were divided into a control group, a ‘PTZ’ group and a ‘PTZ + Sal B’ group. The animals in the control group received an intraperitoneal (i.p.) injection of saline on alternate days for a total of 15 injections and saline orally once a day for 29 days. The animals in the ‘PTZ’ group received PTZ (40 mg/kg, i.p.) on alternate days for a total of 15 injections and saline orally once a day for 29 days. Similarly, the animals in the ‘PTZ + Sal B’ group received PTZ (40 mg/kg, i.p.) on alternate days and Sal B (20 mg/kg) orally once a day for 29 days. Neural density was then evaluated using immunofluorescence (IF) staining of microtubule-associated protein 2 (MAP2). Neuronal apoptosis was detected using terminal deoxynucleotidyl transferase-mediated dUTP nick end-labeling (TUNEL) staining. In addition, the expression of several proteins related to AKT/CREB/BDNF signaling was measured using Western blotting. The results indicated that more severe seizures, decreased neural density, decreased expression of Bcl-2, increased expression of Bax and cleaved caspase-3, and inactivation of AKT/CREB/BDNF signaling occurred in the ‘PTZ’ group in comparison with the control group. However, those changes were suppressed by Sal B. Thus, these data suggest that Sal B has anticonvulsant and anti-apoptotic effects in a PTZ-induced seizure model through activation of the AKT/CREB/BDNF signaling pathways.

Targeting neutrophil extracellular traps enhanced tPA fibrinolysis for experimental intracerebral hemorrhage

The minimally invasive surgery plus fibrinolysis has been identified as a promising treatment for spontaneous intracerebral hemorrhage (ICH). However, the fibrinolytic efficacy is not satisfactory. Neutrophil extracellular traps (NETs) have been demonstrated to impair fibrinolysis in sepsis and acute ischemic stroke. Therefore, we decided to explore the presence and potential effect of NETs in ICH fibrinolysis. Intracerebral hemorrhage was induced by autologous arterial blood injection into the basal ganglia in rats. First, at 0.5 hour, 1 hour, and 1.5 hours after blood injection, the brains were collected for NETs detection by immune-staining. Second, ICH rats were given intrahematoma fibrinolysis: rats were randomized to receive the equal amount of saline, DNAse 1, tissue-plasminogen activator (tPA), and tPA + DNAse 1 at 1 hour after hematoma placement. On day 3, animals were sacrificed for terminal deoxynucleotidyl transferase-mediated dUTP Nick-end labeling staining following MRI and behavioral tests. Third, on day 3 after ICH, the hematoma within brain were collected for ex vivo fibrinolysis assay to further evaluate the effect of NETs in ICH fibrinolysis. Co-staining of DAPI, H3, and MPO confirmed the presence of NETs in ICH. Disintegration of NETs using DNAse 1 enhanced tPA-induced hematoma fibrinolysis, relieved brain swelling, reduced cell death, and improved the functional outcome in ICH rats. Therefore, we concluded that NETs impaired the efficacy of tPA for ICH fibrinolysis in rats. Targeting NETs may be a new alternative to improve the fibrinolytic therapy following ICH.

Resveratrol Promotes Diabetic Wound Healing via SIRT1-FOXO1-c-Myc Signaling Pathway-Mediated Angiogenesis.

Background/Aims: Diabetic non-healing skin ulcers represent a serious challenge in clinical practice, in which the hyperglycemia-induced disturbance of angiogenesis, and endothelial dysfunction play a crucial role. Resveratrol (RES), a silent information regulator 1 (SIRT1) agonist, can improve endothelial function and has strong pro-angiogenic properties, and has thus become a research focus for the treatment of diabetic non-healing skin ulcers; however, the underlying mechanism by which RES regulates these processes remains unclear. Therefore, the present study was intended to determine if RES exerts its observed protective role in diabetic wound healing by alleviating hyperglycemia-induced endothelial dysfunction and the disturbance of angiogenesis.Methods: We investigated the effects of RES on cell migration, cell proliferation, apoptosis, tube formation, and the underlying molecular mechanisms in 33 mM high glucose-stimulated human umbilical vein endothelial cells (HUVECs) by semi-quantitative RT-PCR, western blot analysis, terminal deoxynucleotidyl transferase-mediated dUTP nick end labeling (TUNEL) staining, and immunofluorescence in vitro. We further explored the role of RES on endothelial dysfunction and wound healing disturbance in db/db mice by TUNEL staining, immunofluorescence, and photography in vivo.Results: We observed an obvious inhibition of hyperglycemia-triggered endothelial dysfunction and a disturbance of angiogenesis, followed by the promotion of diabetic wound healing via RES, along with restoration of the activity of the hyperglycemia-impaired SIRT1 signaling pathway. Pretreatment with EX-527, a SIRT1 inhibitor, abolished the RES-mediated endothelial protection and pro-angiogenesis action, and then delayed diabetic wound healing. Furthermore, examination of the overexpression of forkhead box O1 (FOXO1), a transcription factor substrate of SIRT1, in HUVECs and db/db mice revealed that RES activated SIRT1 to restore hyperglycemia-triggered endothelial dysfunction and disturbance of angiogenesis, followed by the promotion of diabetic wound healing in a c-Myc-dependent manner. Pretreatment with 10058-F4, a c-Myc inhibitor, repressed RES-mediated endothelial protection, angiogenesis, and diabetic wound healing.Conclusion: Our findings indicate that the positive role of RES in diabetic wound healing via its SIRT1-dependent endothelial protection and pro-angiogenic effects involves the inhibition of FOXO1 and the de-repression of c-Myc expression.

MicroRNA-26a reduces synovial inflammation and cartilage injury in osteoarthritis of knee joints through impairing the NF-κB signaling pathway.

Objective: Inflammation is closely implicated in the process of osteoarthritis (OA) and affects disease progression and pain. Herein, the present study explored the effect of microRNA-26a (miR-26a) on the synovial inflammation and cartilage injury in OA, with the involvement with the NF-κB signaling pathway.Methods: Rat models of OA were established by anterior cruciate ligament transection, which were then treated with miR-26a mimics/inhibitors or BMS-345541 (inhibitor of NF-κB pathway). The expression of miR-26a and activator proteins of NF-κB pathway (P-IκBα and P-P65) in synovial tissues was determined. Hematoxylin-eosin (HE) staining was adopted to observe pathological changes of knee joints, synovial tissues, and cartilage of femoral condyle. Terminal deoxynucleotidyl transferase-mediated dUTP nick-end labeling (TUNEL) staining was used to detect the apoptosis of synoviocytes and chondrocytes.Results: Poorly expressed miR-26a and increased protein levels of P-IκBα and P-P65 were identified in synovial tissues of OA rats. Besides, OA rats showed obvious synovial tissue hyperplasia, inflammation and cartilage injury of femoral condyle, as well as increased inflammation and cartilage injury scores, and apoptosis of synoviocytes and chondrocytes. In response to miR-26a mimics, protein levels of P-IκBα and P-P65 were reduced; meanwhile, synovial tissue hyperplasia, inflammation and cartilage injury of femoral condyle were ameliorated, with decreased inflammation and cartilage injury scores, and apoptosis of synoviocytes and chondrocytes.Conclusion: MiR-26a suppressed the activation of the NF-κB signaling pathway, by which mechanism the synovial inflammation and cartilage injury in OA rats were alleviated.

Role of the Janus kinase 2/signal transducers and activators of transcription 3 pathway in the protective effect of remote ischemia preconditioning against cerebral ischemia–reperfusion injury in rats

Remote ischemia preconditioning (RIPC) is a convenient and effective method for alleviating cerebral ischemia–reperfusion injury (CIRI). However, to date, the underlying mechanism has not been fully elucidated. The aim of this research was to explore the protective mechanism of RIPC on the brain after CIRI. Four groups of rats were included in this experiment: the sham group, the middle cerebral artery occlusion (MCAO) group, the RIPC group, and the AG490 group. As an inhibitor of Janus kinase 2 (JAK2), AG490 was used after MCAO in the AG490 group to explore the role of JAK2/signal transducers and activators of transcription 3 (STAT3) after CIRI. Brain tissue was collected for evaluation after 2 h of ischemia and 24 h of reperfusion. ELISA for interleukin (IL)-6, IL-1β and tumor necrosis factor-α, western blot for phosphorylated-JAK2 and phosphorylated-STAT3, the neurological severity score and Longa scoring system for neurological deficit evaluation, triphenyltetrazolium chloride staining for cerebral infarction, and terminal deoxynucleotidyl transferase-mediated dUTP nick-end labeling staining for apoptotic cells in the brain tissue were performed. Neurological function in the RIPC group was notably better than that in the MCAO group. There were smaller infarction sizes and fewer apoptotic cells in the ischemic area in the RIPC group than in the MCAO group. In the RIPC group, the expression levels of IL-1β, tumor necrosis factor-α, IL-6, and phosphorylated-JAK2 and phosphorylated-STAT3 were significantly lower than those in the MCAO group. The findings in the RIPC and AG490 groups were similar. The inflammatory response and apoptosis are two important processes involved in brain dysfunction after CIRI. The JAK2/STAT3 signaling pathway has an underlying relationship with these two processes. These findings suggest that RIPC can alleviate the damage to brain tissue by CIRI by regulating the JAK2/STAT3 signaling pathway negatively.

Effect of IL-6-mediated STAT3 signaling pathway on myocardial apoptosis in mice with dilated cardiomyopathy.

To investigate the effect of interleukin-6 (IL-6) gene knockout on apoptosis of myocardial cells in mice with Coxsackievirus B3 (CVB3)-induced dilated cardiomyopathy (DCM) and its potential mechanism, so as to provide certain references for the clinical prevention and treatment of DCM. A total of 40 male C57 mice were randomly divided into Sham group (n=20) and DCM group (n=20) using a random number table. Another 20 mice with IL-6 gene knockout were enrolled into DCM+IL-6 KO group (n=20). The DCM model was established via CVB3 repeated incremental infection. After 9 months, the heart weight/body weight (HW/BW) ratio of mice in each group was detected. The ejection fraction [EF (%)] and fraction shortening [FS (%)] of mice in each group were detected via two-dimensional ultrasonography. The cross-sectional area and pathological changes in myocardial cells in the heart in each group were determined using hematoxylin-eosin (HE) staining. The collagen content in myocardial tissues in each group was detected via Masson staining and picrosirius red (PSR) staining, and the expressions of Collagen I and Collagen III in myocardial tissues in each group were detected via immunohistochemistry. In addition, the myocardial apoptosis in myocardial tissues in each group was detected via terminal deoxynucleotidyl transferase-mediated dUTP nick end labeling (TUNEL) staining. Finally, the protein expression levels of B-cell lymphoma-2 (Bcl-2), Bcl-2 associated X protein (Bax), phosphorylated signal transducer and activator of transcription 3 (p-STAT3), and total STAT3 (t-STAT3) were detected via Western blotting. The expression of IL-6 messenger ribonucleic acids (mRNAs) in myocardial tissues in DCM group was significantly increased compared with that in Sham group (p<0.05). After IL-6 knockout, the HW/BW ratio of DCM mice significantly declined (p<0.05), and the cross-sectional area of myocardial cells was significantly reduced (p<0.05). According to the results of echocardiography, the cardiac function of mice in DCM+IL-6 KO group was significantly superior to that in DCM group, manifested as the significant increase in FS (%) and EF (%) (p<0.05). The results of Masson staining, PSR staining, and immunohistochemical staining showed that IL-6 knockout could reduce the collagen content and Collagen I and Collagen III expressions in myocardial tissues of DCM mice (p<0.05). Furthermore, it was found via TUNEL staining that the number of apoptotic myocardial cells in DCM+IL-6 KO group was markedly smaller than that in DCM group (p<0.05). At the same time, the Bax/Bcl-2 ratio in myocardial tissues in DCM+IL-6 KO group was lower (p<0.05). Finally, the results of Western blotting revealed that DCM+IL-6 KO group had a lower phosphorylation level of STAT3 than DCM group (p<0.05). Inhibiting IL-6 gene may improve the DCM-induced myocardial remodeling through reducing myocardial apoptosis.

Influences of hucMSC-exosomes on VEGF and BMP-2 expression in SNFH rats.

To investigate the influences of human umbilical cord mesenchymal stem cell-derived exosomes (hucMSC-exosome) on steroid-induced necrosis of the femoral head (SNFH) and the expressions of vascular endothelial growth factor (VEGF) and bone morphogenetic protein-2 (BMP-2) in rats. A total of 20 male Sprague-Dawley rats were randomly divided into SNFH group and SNFH + hucMSC-exosome group using a random number table. Prednisolone acetate (24.5 mg/kg) was injected twice a week to establish the rat model of SNFH, and hucMSC-exosome in a certain dose was additionally injected into the marrow cavity in SNFH + hucMSC-exosome group. After 3 weeks, the influences of hucMSC-exosome on the pathological changes and apoptosis of the femoral head in SNFH rats were detected via hematoxylin-eosin (H&E) staining and terminal deoxynucleotidyl transferase-mediated dUTP nick end labeling (TUNEL) staining. In addition, the expressions of cluster of differentiation 31 (CD31), VEGF, and BMP-2 in bone tissues in both groups were detected via immunohistochemical staining, and the messenger ribonucleic acid (mRNA) and protein expression levels of VEGF and BMP-2 in necrotic bone tissues in both groups were detected via Reverse Transcription-Polymerase Chain Reaction (RT-PCR) and Western blotting. The results of H&E staining revealed that the fibrous callus formation was good, the new trabecular structure was more obvious, the number of vacuum cleft declined, and there were fewer enlarged adipocytes in SNFH + hucMSC-exosome group compared with SNFH group. The results of TUNEL staining showed that the number of apoptotic cells in femoral head tissues was smaller in SNFH + hucMSC-exosome group (p<0.05). According to the results of immunohistochemistry, hucMSC-exosome could increase the expression of vascular endothelial marker CD31 in SNFH rats (p<0.05). Besides, the results of RT-PCR, immunostaining and Western blotting manifested that both the mRNA and protein levels of BMP-2 and VEGF in femoral head tissues were significantly increased in SNFH + hucMSC-exosome group (p<0.05). HucMSC-exosome can improve SNFH in rats, whose mechanism may be related to the up-regulation of VEGF and BMP-2 by exosomes.

Epigallocatechin-3-Gallate Attenuates Adriamycin-Induced Focal Segmental Glomerulosclerosis via Suppression of Oxidant Stress and Apoptosis by Targeting Hypoxia-Inducible Factor-1α/ Angiopoietin-Like 4 Pathway

Background: Focal and segmental glomerular sclerosis (FSGS) is a common cause of nephrotic syndrome and end-stage renal disease. It has been reported that overproduction of reactive oxygen species (ROS) and cell apoptosis are associated with the development of FSGS. Epigallocatechin-3-gallate (EGCG) is a bioactive constituent accounting for more than 50% of the total catechins in green tea, which have anti-oxidative and anti-apoptotic effects. Based on this, this study was designed to evaluate the renoprotective effect of EGCG treatment on Adriamycin-induced FSGS. ­Methods: In C57BL/6 mice, Adriamycin nephropathy (AN) was induced by Adriamycin (10 mg/kg body weight, diluted in normal saline) via a tail vein on day 0. Then the mice were given with EGCG (20 mg/kg body weight) or YC-1 (Lificiguat, a specific inhibitor of hypoxia-inducible factor-1α [HIF-1α], 50 mg/kg body weight) or both intraperitoneally. Both the EGCG and YC-1 were given on the day of Adriamycin injection and continued for 6 weeks. The animals were organized into the following 5 groups for the animal experiments: the control group, the AN group, the AN + EGCG group, the AN + YC-1 group and the AN + EGCG + YC-1 group. At 6 weeks, the mice were sacrificed; kidneys and blood samples were collected for further analysis. The HIF-1α and the angiopoietin-like 4 (ANGPTL4) expression were detected by Western blot, real-time PCR, immunohistochemistry or immunofluorescence. Dihydroethidium staining and NADPH oxidase 1 (Nox1) measurement were used to detect ROS production. Terminal deoxynucleotide transferase-mediated dUTP nick end-labeling (TUNEL) staining and caspase-3 measurement was used to detect cell apoptosis. Results: When the animals were treated with Adriamycin, both the ROS production and TUNEL positive cells increased. Besides, the expression of HIF-1α, ANGPTL4, and caspase-3 were also up-regulated, while EGCG treatment could attenuate these changes. Interestingly, compared with treatment with YC-1 or EGCG alone, more pronounced inhibition of ANGPTL4, caspase-3 and Nox1 were obtained when YC-1 and EGCG were administered simultaneously. Conclusion: EGCG attenuates FSGS through the suppression of Oxidant Stress and apoptosis by targeting the HIF-1α/ANGPTL4 pathway.

Penehyclidine hydrochloride exerts protective effects in rats with acute lung injury via the Fas/FasL signaling pathway.

Acute lung injury (ALI) is a critical syndrome that is associated with high morbidity and mortality rates. The activation of the Fas/Fas ligand (FasL) signaling pathway may be an important pathophysiological mechanism during ALI development. Penehyclidine hydrochloride (PHC) has been revealed to exhibit anti-apoptotic properties and may attenuate the observed systemic inflammatory response. The present study was performed to elucidate the molecular mechanism of PHC in the regulation of the Fas/FasL signaling pathway in rats with ALI. An ALI rat model was constructed by inducing blunt chest trauma and hemorrhagic shock (T/HS), with PHC administration prior to or following T/HS. At 6 h following T/HS, blood samples and lung tissues were collected. Western blotting, arterial blood gas analysis, ELISA, hematoxylin and eosin staining, terminal deoxynucleotidyl transferase-mediated dUTP nick-end labeling staining and biochemical indicator analysis were performed to determine the degree of lung injury and the key signaling pathways associated with lung damage. The results indicated that the administration of PHC following T/HS effectively attenuates lung injury by improving pulmonary oxygenation, decreasing histopathological damage, decreasing polymorphonuclear neutrophil count and decreasing Fas, FasL, caspase-8, caspase-3, tumor necrosis factor-α, interleukin (IL)-6 and IL-1β expression. The results indicated that PHC exhibits anti-apoptotic functions and exerts protective effects in ALI rats induced by T/HS, which may be attributed to the inhibition of the Fas/FasL signaling pathway.

Ginkgolide B ameliorates myocardial ischemia reperfusion injury in rats via inhibiting endoplasmic reticulum stress.

PurposeGinkgolide B (GB) is a terpene lactone component found in Ginkgo biloba, which has a protective role on ischemia reperfusion (I/R) injury. This study was aimed at exploring the protective mechanism of GB on the myocardial I/R.Patients and methodsMyocardial I/R model was established on Sprague Dawley rats. The levels of cardiac troponin I, cardiac troponin T, lactic dehydrogenase, and myoglobin were determined by a 200FR NEO automatic biochemical analyzer. Histological examination was performed through HE and terminal deoxynucleotidyl transferase-mediated dUTP nick end-labeling staining. The expression levels of p-PERK, p-IRE1α, ATF6, p-AKT, and mTOR were detected by Western blot.ResultsThe results exhibited that GB treatment suppressed the high levels of cardiac troponin I, cardiac troponin T, lactic dehydrogenase, and myoglobin and ameliorated the damaged and irregularly arranged myocardial cells induced by I/R injury significantly, indicating that GB could ameliorate myocardial I/R injury. Moreover, the high expression levels of endoplasmic reticulum (ER) stress key proteins caused by I/R injury were suppressed significantly by GB treatment, including p-PERK, p-IRE1α, and ATF6. GB treatment also decreased the number of apoptotic cells compared with I/R group. In addition, activation of ER stress by Tunicamycin treatment could counteract the protective effects of GB on I/R injury, suggesting that GB ameliorated myocardial I/R injury through inhibition of ER stress-induced apoptosis. Finally, the decreased p-AKT and p-mTOR expressions caused by I/R injury were upregulated by GB and inhibition of PI3K/AKT/mTOR pathway by LY294002 abolished the protective effects of GB on I/R injury, indicating that GB activated PI3K/AKT/mTOR pathway during I/R injury.ConclusionGB protected against myocardial I/R injury through inhibiting ER stress-induced apoptosis via PI3K/AKT/mTOR signaling pathway.

Inhibition of the PI3K/Akt signaling pathway impedes the restoration of neurological function following hypoxic-ischemic brain damage in a neonatal rabbit model.

Hypoxic-ischemic brain damage (HIBD), frequently occurring in infancy and childhood, is a major cause of mortality and severe neurologic impairment. This study was performed to examine the effect of the PI3K/Akt signaling pathway on HIBD in a neonatal rabbit model. Uterine artery occlusion was used to establish HIBD models in neonatal rabbits, which were then subjected to sham operation, dimethyl sulfoxide (2 mL) or LY294002 (inhibitor of PI3K/Akt signaling pathway, 6.4 μg/kg). Behavioral neurological assessment was performed in neonatal rabbits delivered by cesarean section, after which serum neuron-specific enolase (NSE) level and cerebral water content were determined. The level of cleaved caspase-3 level and apoptosis of neurons were observed by immunohistochemistry and terminal deoxynucleotidyl transferase-mediated dUTP nick-end labeling (TUNEL) staining. Furthermore, the expression of PI3K/Akt signaling pathway- and apoptosis-related factors was examined. In neonatal rabbits, HIBD increased the fetal death rate; reduced neurological scores of posture, righting reflex, and deglutition reflex; elevated serum NSE levels, cerebral water content, cleaved caspase-3-positive expression in hippocampal CA1 region and apoptotic neurons; inactivated PI3K/Akt signaling pathway as well as reduced Bcl-2 expression and increased BAD and Bax expression. Notably, the treatment of LY294002 further aggravated neurological impairment in neonatal rabbits in response to HIBD. Following the HIBD caused by intrauterine asphyxia, the LY294002 administered through auricular vein infusion into pregnant rabbits exacerbates neurological impairment of neonatal rabbits, suggesting that inhibition of PI3K/Akt signaling pathway may serve as a candidate therapeutic target for neurological recovery.