Nitric Oxide Synthase Protein Levels Research Articles

Protection of HT22 neuronal cells against chemically-induced ferroptosis by catechol estrogens: protein disulfide isomerase as a mechanistic target

Ferroptosis is a form of regulated cell death, characterized by excessive iron-dependent lipid peroxidation. Biochemically, ferroptosis can be selectively induced by erastin through glutathione depletion or through inhibition of glutathione peroxidase 4 by RSL3, which leads to accumulation of cytotoxic lipid reactive oxygen species (ROS). Protein disulfide isomerase (PDI) was recently shown to mediate erastin/RSL3-induced ferroptosis and thus also become a new target for protection against chemically-induced ferroptosis. The present study aims to identify endogenous compounds that can protect against erastin/RSL3-induced ferroptotic cell death. We find that 2-hydroxyestrone, 2-hydroxyestradiol, 4-hydroxyestrone and 4-hydroxyestradiol, four major endogenous catechol estrogens, are effective inhibitors of PDI, and can strongly protect against chemically-induced ferroptotic cell death in cultured HT22 mouse hippocampal neuronal cells. The CETSA assay showed that these catechol estrogens can bind to PDI in live cells. PDI knockdown attenuates the protective effect of these catechol estrogens against chemically-induced ferroptosis. Mechanistically, inhibition of PDI’s catalytic activity by catechol estrogens abrogates erastin/RSL3-induced dimerization of nitric oxide synthase, thereby preventing the subsequent accumulation of cellular nitric oxide, ROS and lipid-ROS, and ultimately ferroptotic cell death. In addition, joint treatment of cells with catechol estrogens also abrogates erastin/RSL3-induced upregulation of nitric oxide synthase protein levels, which also contributes to the cytoprotective effect of the catechol estrogens. In conclusion, the present study demonstrates that the catechol estrogens are protectors of HT22 neuronal cells against chemically-induced ferroptosis, and inhibition of PDI’s catalytic activity by these estrogens contributes to a novel, estrogen receptor-independent mechanism of cytoprotection.

Serum-Derived Macrophage-Activating Factor Exhibits Anti-Tumor Activity via M2-to-M1 Macrophage Reprogramming

Many anti-tumor effects of group-specific component-derived macrophage-activating factors (GcMAFs) have been reported; however, the specific mechanisms remain unclear. Controlling tumor-associated macrophages (TAMs) in the tumor microenvironment is essential for cancer treatment. This study assessed the role of GcMAF in macrophage activation, elucidated the mechanisms by which it exerts its anti-tumor effects, and determined its effects on TAMs in the tumor microenvironment. GcMAF-stimulated RAW264.7 macrophages and EMT6 breast tumor cells were co-cultured in a 0.4 µm pore cell culture insert, and gene and protein expression and cell viability were evaluated. DNA microarray analysis of GcMAF-stimulated RAW264.7 cells was conducted. The induction of M2 RAW264.7 cells by interleukin (IL)-4 and IL-13 was analyzed. GcMAF stimulation increased the tumor necrosis factor-α and inducible nitric oxide synthase mRNA and protein levels in RAW264.7 cells but decreased the viability of co-cultured EMT6 cells. Although the details of the receptor or signal pathway of GcMAF are still unclear, these results were confirmed in the M2 RAW264.7 cells, suggesting that GcMAF exerts anti-tumor effects by inducing the differentiation of macrophages into the M1 type and reprogramming M2 macrophages to the M1 type. The anti-tumor activity of GcMAF via M2-to-M1 macrophage reprogramming could aid in developing novel cancer immunotherapies.

Increased Neuronal Nitric Oxide Synthase in Alzheimer's Disease Mediates Spontaneous Calcium Signaling and Divergent Glutamatergic Calcium Responses.

Nitrosative stress is a feature of Alzheimer's disease (AD). Aims: We aimed to identify the cause underpinning increased nitric oxide (NO) in neurons and the impact of NO on neuronal function in AD. Results: We analyzed neuronal nitric oxide synthase (nNOS) protein levels in postmortem tissue and induced pluripotent stem cell (iPSC)-derived neurons from Alzheimer's patients and controls by immunohistochemistry and Western blots. Furthermore, we assessed the impact of modulating nNOS function or NO levels on neuronal glutamatergic signaling using calcium imaging. We show that nNOS protein levels are increased in early and severely affected brain regions of AD postmortem tissue, but not late and mildly affected regions, or cognitively normal individuals. The increased nNOS phenotype was also present in iPSC-derived neurons from late-onset Alzheimer's disease (LOAD) patients compared with controls, along with increased levels of nitrite, a stable marker of NO. Innovation: We observed a divergent functional impact of NO that included strengthening the calcium response in control neurons, while dysregulating calcium signaling and altering the amplitude and kinetics of the calcium responses to glutamate in the AD neurons. Pharmacological scavenging of NO or inhibition of nNOS prevented aberrant spontaneous calcium signaling in AD neurons. Conclusion: Together these data identify increases in nNOS protein in AD. Functional data suggest that NO modulation of glutamatergic calcium signaling is neuroprotective under nonpathogenic conditions, with increased nNOS and NO contributing to dysregulated spontaneous calcium signaling in AD neurons.

Voluntary exercise does not increase gastrointestinal motility but increases spatial memory, intestinal eNOS, Akt levels, and Bifidobacteria abundance in the microbiome.

The interaction between the gut and brain is a great puzzle since it is mediated by very complex mechanisms. Therefore, the possible interactions of the brain-exercise-intestine-microbiome axis were investigated in a control (C, N = 6) and voluntarily exercised (VE, N = 8) middle-aged rats. The endurance capacity was assessed by VO2max on the treadmill, spatial memory by the Morris maze test, gastrointestinal motility by EMG, the microbiome by 16S RNA gene amplicon sequencing, caveolae by electron microscopy, and biochemical assays were used to measure protein levels and production of reactive oxygen species (ROS). Eight weeks of voluntary running increased VO2max, and spatial memory was assessed by the Morris maze test but did not significantly change the motility of the gastrointestinal tract or production of ROS in the intestine. The protein kinase B (Akt) and endothelial nitric oxide synthase (eNOS) protein levels significantly increased in the intestine, while peroxisome proliferator-activated receptor gamma coactivator 1 alpha (PGC-1α), mitochondrial transcription factor A (TFAM), nuclear respiratory factor 1 (NFR1), SIRT1, SIRT3, nicotinamide phosphoribosyl transferase (NAMPT), and nuclear factor κB (NF-κB) did not change. On the other hand, voluntary exercise increased the number of caveolae in the smooth muscles of the intestine and relative abundance of Bifidobacteria in the microbiome, which correlated with the Akt levels in the intestine. Voluntary exercise has systemic effects and the relationship between intestinal Akt and the microbiome of the gastrointestinal tract could be an important adaptive response.

Exercise-induced angiogenesis is attenuated by captopril but maintained under perindopril treatment in hypertensive rats.

Angiogenesis is an important exercise-induced response to improve blood flow and decrease vascular resistance in spontaneously hypertensive rats (SHR), but some antihypertensive drugs attenuate this effect. This study compared the effects of captopril and perindopril on exercise-induced cardiac and skeletal muscle angiogenesis. Forty-eight Wistar rats and 48 SHR underwent 60 days of aerobic training or were kept sedentary. During the last 45 days, rats were treated with captopril, perindopril or water (Control). Blood pressure (BP) measurements were taken and histological samples from the tibialis anterior (TA) and left ventricle (LV) muscles were analyzed for capillary density (CD) and vascular endothelial growth factor (VEGF), VEGF receptor-2 (VEGFR-2) and endothelial nitric oxide synthase (eNOS) protein level. Exercise increased vessel density in Wistar rats due to higher VEGFR-2 (+17%) and eNOS (+31%) protein level. Captopril and perindopril attenuated exercise-induced angiogenesis in Wistar rats, but the attenuation was small in the perindopril group, and this response was mediated by higher eNOS levels in the Per group compared to the Cap group. Exercise increased myocardial CD in Wistar rats in all groups and treatment did not attenuate it. Both exercise and pharmacological treatment reduced BP of SHR similarly. Rarefaction was found in TA of SHR compared to Wistar, due to lower levels of VEGF (-26%) and eNOS (-27%) and treatment did not avoid this response. Exercise prevented these reductions in control SHR. While rats treated with perindopril showed angiogenesis in the TA muscle after training, those rats treated with captopril showed attenuated angiogenesis (-18%). This response was also mediated by lower eNOS levels in Cap group compared with Per and control group. Myocardial CD was reduced in all sedentary hypertensive compared with Wistar and training restored the number of vessels compared with sedentary SHR. In conclusion, taken into account only the aspect of vessel growth, since both pharmacological treatments reduced BP in SHR, the result of the present study suggests that perindopril could be a drug of choice over captopril for hypertensive practitioners of aerobic physical exercises, especially considering that it does not attenuate angiogenesis induced by aerobic physical training in skeletal and cardiac muscles.

NEDD4 attenuates oxidized low‑density lipoprotein‑induced inflammation and dysfunction in vascular endothelial cells via regulating APEX1 expression.

Atherosclerosis chiefly results from inflammation as well as vascular endothelial cell dysfunction. Methylation levels of neuronally expressed developmentally downregulated 4 (NEDD4) were found to be fortified in atherosclerosis patients and NEDD4 deficiency enhanced vascular calcification. However, the exact function of NEDD4 in inflammation and vascular endothelial dysfunction remains to be elucidated. In the present study, CCK-8 assay was used to estimate cell viability. Reverse transcription-quantitative PCR was adopted to examine the expression of NEDD4, inflammation-associated enzymes and apurinic/apyrimidinic endodeoxyribonuclease 1 (APEX1). Western blotting was used to test NEDD4, endothelial nitric oxide synthase, inducible nitric oxide synthase and APEX1 protein levels. Cytotoxicity was detected by a lactate dehydrogenase (LDH) kit. Reactive oxygen species level was tested by a corresponding kit. Vascular cell adhesion molecule 1 and intercellular adhesion molecule 1 contents were examined with ELISA. Cell adhesion assays evaluated the adhesion of endothelial cells. Co-immunoprecipitation assay was used to test the relationship between NEDD4 and APEX1. The data revealed that NEDD4 expression rapidly declined in oxidized low density lipoprotein (ox-LDL)-induced human umbilical vein endothelial cells (HUVECs). Following NEDD4 overexpression, the active damage, inflammatory release and endothelial cell dysfunction in ox-LDL-induced HUVECs were attenuated. After co-transfection of APEX1 interference plasmids and NEDD4 overexpression plasmids, cell damage, inflammatory release and endothelial cell dysfunction in ox-LDL-induced HUVECs were improved again. Taken together, NEDD4 attenuated ox-LDL-induced inflammation and endothelial dysfunction by regulating APEX1 expression.

Investigation of the neuroprotective effect of kefir in experimental spinal cord injury

In this study, the antioxidant, anti-inflammatory, and neuroprotective effects of kefir were investigated in spinal cord injury that was experimentally created on rats with a compression trauma model. A total of 56 Wistar-Albino male rats were used in the study. Daily freshly prepared 18 ml/kg/day of kefir was given by oral gavage to animals 7 days before and during the trauma and during the trauma. Spinal cord injury was created according to the weight drop method. On the 1st and 7th days before euthanasia, intracardiac blood was collected for analysis, and then they were sacrificed. The damaged spinal cord segments were examined biochemically, immunohistochemically, and histopathologically. When compared to the sham groups, kefir had a positive effect in the preconditioning and treatment groups by decreasing spinal cord bleeding, edema, myelin sheath damage, liquefactive necrosis, neuronal necrosis, selectivity of canalis centralis, and gitter cell levels significantly. When compared to the sham groups, kefir was found to have a positive effect in the treatment groups by decreasing the neuron specific enolase (NSE), ionized calcium binding adapter molecule 1 (IBA-1), inducible nitric oxide synthase (INOS), cyclooxygenase 2 (COX-2) and myelin basic protein (MBP) levels significantly on the 1st and 7th days, and by increasing the glial fibrillary acidic protein (GFAP) level significantly. As a result, it was demonstrated that kefir had a protective and therapeutic effect on spinal cord injury.

Renoprotection and Its Mechanism of Fasudil in Nitric Oxide Synthase-Deficient Hypertensive Rats

Abstract Background To investigate whether fasudil can improve renal microcirculation and protect the kidney in NG-nitro-l-arginine methyl ester (l-NAME)-induced hypertensive rats by inhibiting Rho/Rho associated coiled-coil containing protein kinase (ROCK) signal pathway. Methods The nitric oxide-deficient hypertension was induced by l-NAME (60 mg/l·d) which was provided in drinking water for 8 weeks in Wistar rats. Then they were randomly divided into l-NAME and l-NAME + fasudil groups. Blood, urine, and left kidney samples were collected after fasudil intervention for 6 weeks. Renal artery blood flow, renal function markers in serum and urine, morphological changes of renal interlobular artery, and expression levels of related proteins were detected. Results Compared with normal control rats, the levels of serum creatinine (SCr) and blood urea nitrogen (BUN) increased while creatinine clearance (CCr) decreased in l-NAME rats. Fasudil treatment significantly decreased SCr and BUN, and increased CCr compared with l-NAME group. Compared with normal controls, the intima of renal interlobular artery increased, the lumen narrowed, the expression of ROCK-1, phosphorylated myosin phosphatase 1/myosin phosphatase 1 (p-MYPT1/MYPT1) increased while endothelial nitric oxide synthase (eNOS) protein levels decreased in l-NAME group (all P < 0.05). Fasudil treatment reduced intimal hyperplasia and lumen stenosis of renal interlobular artery, downregulated ROCK-1 and p-MYPT protein levels and upregulated eNOS expression in l-NAME rats (all P < 0.05). Conclusions Fasudil treatment improves renal function and structure of renal interlobar artery in nitric oxide-deficient hypertensive rats induced by l-NAME.

Anti-Inflammatory and Anti-Oxidant Effects of Epilobium amurense subsp. cephalostigma via Activation of Nrf2/HO-1 and Inhibition of NF-κB/p38 MAPK Signaling in LPS-Stimulated Macrophages

The genus Epilobium consists of approximately 200 species that are distributed worldwide. Some of these herbs have been used for the treatment of diarrhea, infection, irritation, and other disorders associated with inflammation. Unlike that of other Epilobium species, there is little scientific understanding of the pharmacological effect of Epilobium amurense subsp. cephalostigma (Hausskn.) C. J. Chen, Hoch & P. H. Raven. In this study, we demonstrated the anti-inflammatory and antioxidative properties of an E. amurense 95% ethanol extract (EACEE) in lipopolysaccharide (LPS)-stimulated RAW 264.7 macrophages, and observed the underlying mechanism of this effect. We measured the productions of nitric oxide (NO) and reactive oxygen species, and examined the actions of EACEE on transcription factors in the macrophages. EACEE reduced NO production and inducible nitric oxide synthase protein levels via the inhibition of the nuclear factor (NF)-κB pathway. Additionally, EACEE suppressed redundant reactive oxygen species production and regulated nuclear factor erythroid 2-related factor 2/heme oxygenase-1 (Nrf2/HO-1) signaling. Furthermore, EACEE significantly inhibited the phosphorylation of p38 mitogen-activated protein kinase (MAPK). Overall, these results indicate that EACEE exerts anti-inflammatory and antioxidant effects via the activation of Nrf2/HO-1 and inhibition of NF-κB/p38 MAPK signaling.

Anticancer profile and anti-inflammatory effect of new N-(2-((4-(1,3-diphenyl-1H-pyrazol-4-yl)pyridine sulfonamide derivatives

A new series of N-(2-((4-(1,3-diphenyl-1H-pyrazol-4-yl)pyridine sulfonamide derivatives 11a-o were designed and synthesized based on our previous works. The new series was tested for its anticancer and anti-inflammatory effects. The anticancer profile of final target compounds was obtained by testing them over 60 cell lines belong to nine types of cancers. Compound 11c showed the highest percent inhibition, so its potency was measured over the most sensitive cell line to determine its IC50 over each cell. In addition, compound 11c was tested over kinase panel to get its biological target(s). Compound 11c had strong activity over JNK1, JNK2, p38a and V600EBRAF. All final target compounds were tested against the four kinases to build a structure activity relationship. Compound 11c was subjected to cell cycle analysis to check at which phase is affected by 11c. The anti-inflammatory effect of final target compounds was screened by testing their ability to inhibit both nitric oxide release and prostaglandin E2 production on raw 264.7 macrophages in addition to test their cytotoxic effect on the same cells. Compound 11n showed the highest ability to inhibit prostaglandin E2 and all compound showed moderate to low activity regarding inhibition of nitric oxide release. Compound 11n was investigated for its ability to reduce Interleukin 6 and TNF-alpha. In addition, compound 11n was tested for its effect on induced Nitric oxide synthase (iNOS), and COX-2 mRNA expression level and its effect on nitric oxide synthase (iNOS), COX-1 and COX-2 protein levels where it showed selectivity for COX-2 compared to COX-1 and iNOS.

Oxaliplatin, an Anticancer Agent, Causes Erectile Dysfunction in Rats due to Endothelial Dysfunction

Chemotherapeutics, one of the standard treatment options for cancer worldwide, have various adverse effects, including erectile dysfunction (ED). To investigate erectile function in an animal model after administration of the anticancer agent oxaliplatin (L-OHP). Male Wistar/ST rats were divided into 2 groups: L-OHP rats (n = 21), which were intravenously administered L-OHP (4 mg/kg; twice a week for 4 weeks), and Control rats (n = 21), which were injected with the same volume of 5% glucose solution, using the same dosing schedule. At the end of the study period, erectile function was evaluated by measuring intracavernous pressure (ICP) and mean arterial pressure (MAP) after cavernous nerve stimulation (n = 9-10). Endothelial function was evaluated with an isometric tension study using corpus cavernosum strips (n = 11). Western blot analysis was used to assess neuronal nitric oxide (nNOS) and endothelial NO synthase (eNOS) protein levels (n = 7). Real-time quantitative polymerase chain reaction (qRT-PCR) was used to assess the expression of inflammation- and oxidative stress-related markers (nicotinamide adenine dinucleotide phosphate oxidase-1, p22phox, interleukin [IL]-6, and nuclear factor-kappa B) (n = 6). Statistical significance was determined using the Student's t-test. The L-OHP group had a significantly lower ICP:MAP ratio than the control group (P < .05). Compared to the Control group, the L-OHP group exhibited significantly lower responses to ACh and eNOS protein levels and significantly higher inflammatory biomarker levels. The results based on this animal model indicate that use of the anticancer agent L-OHP should be considered as a risk factor for ED occurring via reduction of NO bioavailability in humans; our results provide possible treatment strategies for maintaining the erectile function of cancer survivors. Our study showed that the anticancer agent L-OHP has the propensity to cause ED in rats. A major limitation of this study is the lack of an established cure for ED associated with L-OHP and the lack of clinical evidence. L-OHP causes ED in rats via reduction of NO bioavailability caused by endothelial dysfunction.

Extra Virgin Olive Oil Phenolic Extract on Human Hepatic HepG2 and Intestinal Caco-2 Cells: Assessment of the Antioxidant Activity and Intestinal Trans-Epithelial Transport.

In the framework of research aimed at promoting the nutraceutical properties of the phenolic extract (BUO) obtained from an extra virgin olive oil of the Frantoio cultivar cultivated in Tuscany (Italy), with a high total phenols content, this study provides a comprehensive characterization of its antioxidant properties, both in vitro by Trolox equivalent antioxidant capacity, oxygen radical absorbance capacity, ferric reducing antioxidant power, and 2,2-diphenyl-1-picrylhydrazyl assays, and at the cellular level in human hepatic HepG2 and human intestinal Caco-2 cells. Notably, in both cell systems, after H2O2 induced oxidative stress, the BUO extract reduced reactive oxygen species, lipid peroxidation, and NO overproduction via modulation of inducible nitric oxide synthase protein levels. In parallel, the intestinal transport of the different phenolic components of the BUO phytocomplex was assayed on differentiated Caco-2 cells, a well-established model of mature enterocytes. The novelty of our study lies in having investigated the antioxidant effects of a complex pool of phenolic compounds in an extra virgin olive oil (EVOO) extract, using either in vitro assays or liver and intestinal cell models, rather than the effects of single phenols, such as hydroxytyrosol or oleuropein. Finally, the selective trans-epithelial transport of some oleuropein derivatives was observed for the first time in differentiated Caco-2 cells.

L-Arginine inhibits hydrogen peroxide-induced oxidative damage and inflammatory response by regulating antioxidant capacity in ovine intestinal epithelial cells

Little is known how L-arginine (Arg) affects the ovine intestinal epithelial cells (IOECs) redox status induced by hydrogen peroxide (H2O2). This study aimed to examine the impact of Arg on IOECs subjected to H2O2-induced oxidative damage, intestinal barrier injury, and inflammatory response. The IOECs were incubated for 16 h then classified as four groups (n = 6/group) and cultured in corresponding media including (1) control (CON) group, in which IOECs were cultured in Arg-free Dulbecco’s modified Eagle’s F12 Ham medium (DMEM) containing 100 μM Arg; (2) Arg group, in which IOECs were cultured in Arg-free DMEM containing 350 μM Arg; (3) H2O2 group, in which IOECs were cultured in CON group plus 150 μM H2O2; (4) Arg + H2O2 group, in which IOECs were cultured in Arg group plus150 μM H2O2. After culturing for 24 h in media, some characteristics of cells in the four groups were measured. Arg administration decreased the H2O2-induced reactive oxygen species (ROS) production compared with the H2O2 group (p < .05). Compared with H2O2, adding Arg to H2O2 increased (p < .05) transepithelial electrical resistance (TEER), but decreased (p < .05) tumour necrosis factor α (TNF-α) within the IOECs. Compared with H2O2, adding Arg to H2O2-induced injured IOECs increased (p < .05) glutathione peroxidase 1 (GPx1), zonula occludens-1 (ZO-1), and epithelial nitric oxide (NO) synthase (eNOS) protein levels, and decreased (p < .05) TNF-α levels within cells. Arg inhibits H2O2-induced oxidative damage, intestinal barrier injury, and inflammatory response by NO pathway within IOECs. HIGHLIGHTS Arg inhibits H2O2-induced oxidative damage of IOECs. Arg inhibits H2O2-induced barrier injury of IOECs. Arg inhibits H2O2-induced inflammatory of IOECs. Arg modulates the antioxidant activity by a NO pathway in IOECs.

Racial Differences in p66shc Activity in Activated Endothelial Cells

BackgroundOxidative stress plays a pivotal role in the development of endothelial dysfunction and the pathophysiology of atherosclerosis. P66shc is an adaptor protein that acts as a redox‐sensitive enzyme involved in mitochondrial reactive oxygen species (ROS) production. Upon endothelial cell activation, protein kinase C‐β2 (PKC‐β2) mediates Ser36 phosphorylation of p66shc, thereby allowing p66shc translocation from the cytosol to the mitochondria. Furthermore, we have shown that African American (AA) endothelial cells display higher levels of inflammation and oxidative stress markers compared to Caucasian American (CA) endothelial cells. Therefore, the purpose of this study was to investigate racial differences in p66shc activity in response to tumor necrosis factor‐α (TNF‐α)‐induced endothelial cell activation.MethodsHuman umbilical vein endothelial cells (HUVECs) from three AA donors and three CA donors were cultured and incubated with TNF‐α (10ng/ml, 4hr) to assess racial differences in p66shc, PKC‐β2 and endothelial nitric oxide synthase (eNOS) protein levels and bioactivity.ResultsEnzymatically active eNOS (p‐eNOSS1177) was significantly lower in AA HUVECs under both basal and TNF‐α incubation conditions (p= 0.01, Fig. 1A). Additionally, p‐Ser36 p66shc/total p66shc was significantly lower in AA HUVECs compared to CA HUVECs (p= 0.04, Fig. 3C). However, there was no group or treatment effect on any on the other variables measured.Conclusionp66shc represents an important molecular pathway that mediates ROS production and plays an integral role in the development of cardiovascular disease. According to our results, racial differences in endothelial function cannot be explained by p66shc. However, future research should focus on assessing cytosolic vs. mitochondrial p66shc levels in AA endothelial cells compared to CA.eNOS protein expression and bioactivity in CA and AA HUVECs after 4 hours of incubation with TNF‐α (10ng/ml).A) Densiometric quantification and representative Western blot of p‐eNOS. B) Densiometric quantification and representative Western blot of eNOS. C) p‐eNOS bioactivity. (* p= .01 vs. CA HUVECs, n= 4 independent experiments. Data are shown as mean ± SEM).Figure 1p66shc protein expression and bioactivity in CA and AA HUVECs after 4 hours of incubation with TNF‐α (10ng/ml).A) Densiometric quantification and representative Western blot of p‐p66shc. B) Densiometric quantification and representative Western blot of p66shc. C) p‐p66shc bioactivity. (* p= .04 vs. CA HUVECs, n= 4 independent experiments. Data are shown as mean ± SEM).Figure 2

Neuroprotective activity of different monosaccharide‐modified gastrodin analogs

AbstractGastrodin is a very important and well‐known bioactive glycoside compound in Chinese medicine. It is also known as a drug with neuroprotective function. Here, a practical diversified synthesis of a series of gastrodin analogs was reported, which involved four‐step procedures consisting of bromination, oxidation, etherification, and reduction. Various gastrodin analogs were obtained in good yields. The compound 4c in this study has a good neuroprotective function: it can significantly downregulate tumor necrosis factor‐α and inducible nitric oxide synthase protein levels. The results of this study can provide a research basis for the development of neuroprotective drugs.

Pulsed magnetic field maintains vascular homeostasis against H2O2-induced oxidative stress.

Pulsed magnetic fields (PMFs) have significant therapeutic effects on many disorders. However, the effects of PMF on vascular homeostasis remain unclear. Therefore, in the present study, we investigated the role of in vivo PMF in maintaining vascular homeostasis during H2O2-induced oxidative stress. For this purpose, rats were exposed to PMF (40 Hz, 1.5 mT) for 1 h for a period of 30 days, following which their thoracic aortas were excised. H2O2 was exogenously applied to the aortic rings. Constrictions were measured in a tissue bath using an electrophysiological technique. Bcl-2 and endothelial nitric oxide synthase (eNOS) protein levels were determined by Western blotting. We found lesser H2O2-induced vasoconstriction in the PMF group than in the control group in endothelium-intact (E+) rings. As H2O2 also induces apoptosis, after incubation with H2O2 (40 min) to induce early apoptosis, we added KCl and measured KCl-induced contractions. All the groups, endothelium intact or denuded (E-) showed decreased responses; however, we still observed the effect of PMF in the E+ group due to increased endothelial activity. In addition, PMF increased the expression of the eNOS protein, which might be a key target of PMF. Our results suggest that in vivo application of PMF protects vascular responses through endothelium-mediated mechanisms during oxidative stress. Therefore, PMF might play a protective role against vascular diseases.

Estrogenic and anti-inflammatory effects of pseudoprotodioscin in atherosclerosis-prone mice: Insights into endothelial cells and perivascular adipose tissues

Pseudoprotodioscin (PPD), a phytoestrogen isolated from Dioscorea nipponica Makino, is recognized to possess anti-inflammatory and antiadipogenic capacities. However, little is known about the antiatherosclerotic effects of PPD and the underlying mechanisms. Here, the contribution of estrogen receptors (ERs) and inflammation to PPD-mediated amelioration of endothelial dysfunction has been fully assessed. PPD administration alleviated atherosclerotic lesions by lowering total cholesterol in ovariectomized apoE−/- mice fed a high-cholesterol diet. Molecular docking analysis suggested a selective interaction of PPD with ERα. Upon PPD treatment, ERα and endothelial nitric oxide synthase (eNOS) protein levels were increased, whereas cell adhesion molecule and monocyte chemoattractant protein-1 (MCP-1) mRNA levels were suppressed in human umbilical vein endothelial cells (HUVECs) after injury caused by oxidized low-density lipoprotein (ox-LDL). These effects could be abolished by an ERα antagonist or a NOS inhibitor. Whereas, PPD can ERα-independently suppress TNFα expression in peritoneal macrophages upon LPS induction. Estrogen deficiency induced inflammatory phenotypes in perivascular adipose tissue (PAT), which could be partially attenuated by PPD. The increased release of adiponectin in PAT after PPD treatment is in accordance with previous reported data showing that adiponectin exerts anti-inflammatory effects in multiple cell types. ERα-dependent antiadipogenic effects of PPD were also detected in PAT-derived stromal cells. The present study reveals a novel mechanism through which PPD exerts estrogenic and anti-inflammatory properties in atherosclerosis-prone mice. Thus, PPD is a promising compound which has potential therapeutic effects on atherosclerotic cardiovascular diseases in postmenopausal women.

Effect of dehydroepiandrosterone on the immune response and gut microbiota in dextran sulfate sodium-induced colitis mice

Dehydroepiandrosterone (DHEA) possess anti-inflammatory, anti-oxidant and immune-regulating function in animals and humans, but there is not enough information about the mechanisms underlying its beneficial effects. The present study investigated the effect and mechanism of DHEA in dextran sulfate sodium (DSS)-induced colitis mice. The findings showed that DHEA relieved the decreasing of body weight, the increasing of disease activity index, the enhancing of spleen weight, the shortening of colon length and the rising of myeloperoxidase activity; meanwhile, histopathological analysis showed that DHEA maintained a relatively intact structure of colon in DSS-induced colitis mice. DHEA decreased the malondialdehyde content, superoxide dismutase activity and inducible nitric oxide synthase protein level; meanwhile, DHEA also inhibited the secretion of tumor necrosis factor-α, interleukin-1β and interleukin-6 in DSS-induced colitis mice. Importantly, our results showed that DHEA blocked the activation of nuclear factor-kappa B (NF-κB) and p38 mitogen-activated protein kinase (MAPK) pathways; and it inhibited the Nod-like receptor protein 3 inflammasome activation in DSS-induced colitis mice. Furthermore, DHEA markedly promoted the intestinal barrier function by up-regulation zonula occludens-1 expression level. The 16S rDNA gene sequencing demonstrated that DHEA decreased the Pseudomonas abundance in DSS-induced colitis mice. In conclusion, our data demonstrated that DHEA reduces oxidative damage through regulating antioxidant enzyme activity; inhibits pro-inflammatory cytokines production by blocking the activation of p38 MAPK and NF-κB signal pathway; protects colon barrier integrity via increasing tight junction protein expression and modulating gut microbiota taxa; all that finally alleviates DSS-induced experimental colitis in mice.

Cilostazol Promotes Angiogenesis and Increases Cell Proliferation After Myocardial Ischemia–Reperfusion Injury Through a cAMP-Dependent Mechanism

Previous study indicated the protective role of cilostazol in ischemia-reperfusion (I/R) injury. Here, we aimed to explore the function of cilostazol in myocardial I/R injury and the underlying mechanism. The myocardial I/R injury rat model was constructed, and the expression levels of vascular endothelial growth factor (VEGF), hepatocyte growth factor (HGF), basic fibroblast growth factor (bFGF), platelet-derived growth factor receptor b (PDGF-B) and the number of new blood vessels were measured by qRT-PCR and immunohistochemistry. VSMC and HUVEC cells were treated with hypoxia to induce in vivo I/R injury model. The protein expression of AKT, endothelial nitric oxide synthase (eNOS) and apoptosis-related protein levels were detected by western blotting. Besides, the positive staining rate and cell viability were tested by 5-bromo-2-deoxyuridine (Brdu)/4',6-diamidino-2-phenylindole (DAPI) or DAPI/TdT-mediated dUTP Nick-End Labeling (TUNEL) staining and MTT assay. Cilostazol promoted angiogenesis by increasing the number of new blood vessels and up-regulating the expression of VEGF, HGF, bFGF and PDGF-B in myocardial I/R-injury rat model. The in vitro experiments showed that cilostazol increased the level of eNOS and AKT, and also enhanced cell proliferation in hypoxia-treated VSMC and HUVEC cells. Furthermore, after 8-Br-cAMP treatment, VEGF, HGF, bFGF, PDGF-B, p-AKT and p-eNOS expression were up-regulated, while cleaved-caspase 3 and cleaved-PARP expression were down-regulated. In addition, the effects of cilostazol on cell viability and apoptosis were aggravated by 8-Br-cAMP and attenuated after KT-5720 treatment. Cilostazol could promote angiogenesis, increase cell viability and inhibit cell apoptosis, consequently protecting myocardial tissues against I/R-injury through activating cAMP.

Dehydroepiandrosterone alleviates E. Coli O157:H7-induced inflammation by preventing the activation of p38 MAPK and NF-κB pathways in mice peritoneal macrophages

As an important metabolite in cholesterol metabolism, dehydroepiandrosterone (DHEA) can modulate the immune function in animals and humans, but the underlying mechanism is still unclear. The present study investigated the effect and mechanism of DHEA’s anti-inflammatory action in primary mice peritoneal macrophages infected with E. coli O157:H7. The finding showed that DHEA improved the phagocytic ability in E. coli O157:H7-infected macrophages. DHEA inhibited the cytokines (including tumor necrosis factor-α, interleukin-1β and interleukin-6) secretion in E. coli O157:H7-infected macrophages. The inducible nitric oxide synthase and cyclooxygenase-2 protein level were significantly decreased in E. coli O157:H7-infected macrophages treated with DHEA. In addition, DHEA markedly decreased the phospho (p)-p38 MAPK protein level in E. coli O157:H7-infected macrophages. Furthermore, DHEA prevented the nuclear translocation of NF-κB by decreasing of p-IκB-α protein level in E. coli O157:H7-infected macrophage; and these effects of DHEA were heightened when the cells were pre-treated with p38 MAPK inhibitor SB203580. Our data indicated that DHEA alleviates the pro-inflammatory mediator production in E. coli O157:H7-infected mice peritoneal macrophages; and this beneficial action associated with it prevents the activation of p38 MAPK and NF-κB signaling pathway.