Momordica charantia polysaccharides could protect against cerebral ischemia/reperfusion injury through inhibiting oxidative stress mediated c-Jun N-terminal kinase 3 signaling pathway

Targeting RNS/caveolin-1/MMP signaling cascades to protect against cerebral ischemia-reperfusion injuries: potential application for drug discovery

Reactive nitrogen species (RNS) play important roles in mediating cerebral ischemia-reperfusion injury. RNS activate multiple signaling pathways and participate in different cellular events in cerebral ischemia-reperfusion injury. Recent studies have indicated that caveolin-1 and matrix metalloproteinase (MMP) are important signaling molecules in the pathological process of ischemic brain injury. During cerebral ischemia-reperfusion, the production of nitric oxide (NO) and peroxynitrite (ONOO⁻), two representative RNS, down-regulates the expression of caveolin-1 (Cav-1) and, in turn, further activates nitric oxide synthase (NOS) to promote RNS generation. The increased RNS further induce MMP activation and mediate disruption of the blood-brain barrier (BBB), aggravating the brain damage in cerebral ischemia-reperfusion injury. Therefore, the feedback interaction among RNS/Cav-1/MMPs provides an amplified mechanism for aggravating ischemic brain damage during cerebral ischemia-reperfusion injury. Targeting the RNS/Cav-1/MMP pathway could be a promising therapeutic strategy for protecting against cerebral ischemia-reperfusion injury. In this mini-review article, we highlight the important role of the RNS/Cav-1/MMP signaling cascades in ischemic stroke injury and review the current progress of studies seeking therapeutic compounds targeting the RNS/Cav-1/MMP signaling cascades to attenuate cerebral ischemia-reperfusion injury. Several representative natural compounds, including calycosin-7-O-β-D-glucoside, baicalin, Momordica charantia polysaccharide (MCP), chlorogenic acid, lutein and lycopene, have shown potential for targeting the RNS/Cav-1/MMP signaling pathway to protect the brain in ischemic stroke. Therefore, the RNS/Cav-1/MMP pathway is an important therapeutic target in ischemic stroke treatment.

Targeting the Dvl-1/β-arrestin2/JNK3 interaction disrupts Wnt5a-JNK3 signaling and protects hippocampal CA1 neurons during cerebral ischemia reperfusion

It is well known that Wnt5a activation plays a pivotal role in brain injury and β-arrestin2 induces c-Jun N-terminal kinase (JNK3) activation is involved in neuronal cell death. Nonetheless, the relationship between Wnt5a and JNK3 remains unexplored during cerebral ischemia/reperfusion (I/R). In the present study, we tested the hypothesis that Wnt5a-mediated JNK3 activation via the Wnt5a-Dvl-1-β-arrestin2-JNK3 signaling pathway was correlated with I/R brain injury. We found that cerebral I/R could enhance the assembly of the Dvl-1-β-arrestin2-JNK3 signaling module, Dvl-1 phosphorylation and JNK3 activation. Activated JNK3 could phosphorylate the transcription factor c-Jun, prompt caspase-3 activation and ultimately lead to neuronal cell death. To further explore specifically Wnt5a mediated JNK3 pathway activation in neuronal injury, we used Foxy-5 (a peptide that mimics the effects of Wnt5a) and Box5 (a Wnt5a antagonist) both in vitro and in vivo. AS-β-arrestin2 (an antisense oligonucleotide against β-arrestin2) and RRSLHL (a small peptide that competes with β-arrestin2 for binding to JNK3) were applied to confirm the positive signal transduction effect of the Dvl-1-β-arrestin2-JNK3 signaling module during cerebral I/R. Furthermore, Box5 and the RRSLHL peptide were found to play protective roles in neuronal death both in vivo global and focal cerebral I/R rat models and in vitro oxygen glucose deprivation (OGD) neural cells. In summary, our results indicate that Wnt5a-mediated JNK3 activation participates in I/R brain injury by targeting the Dvl-1-β-arrestin2/JNK3 interaction. Our results also point to the possibility that disrupting Wnt5a-JNK3 signaling pathway may provide a new approach for stroke therapy.

Pre-treated Populus tomentiglandulosa extract inhibits neuronal loss and alleviates gliosis in the gerbil hippocampal CA1 area induced by transient global cerebral ischemia

The genus Populus (poplar) belonging to the Salicaceae family has been used in traditional medicine, and its several species show various pharmacological properties including antioxidant and anti-inflammatory effects. No study regarding protective effects of Populus species against cerebral ischemia has been reported. Therefore, in the present study, we examined neuroprotective effects of ethanol extract from Populus tomentiglandulosa (Korea poplar) in the hippocampal cornu ammonis (CA1) area of gerbils subjected to 5 minutes of transient global cerebral ischemia. Pretreatment with 200 mg/kg of P. tomentiglandulosa extract effectively protected CA1 pyramidal neurons from transient global cerebral ischemia. In addition, glial fibrillary acidic protein immunoreactive astrocytes and ionized calcium binding adapter molecule 1 immunoreactive microglia were significantly diminished in the ischemic CA1 area by pretreatment with 200 mg/kg of P. tomentiglandulosa extract. Briefly, our results indicate that pretreatment with P. tomentiglandulosa extract protects neurons from transient cerebral ischemic injury and diminish cerebral ischemia-induced reactive gliosis in ischemic CA1 area. Based on these results, we suggest that P. tomentiglandulosa can be used as a potential candidate for prevention of ischemic injury.

Effect of Intrauterine Infusion of Momordica Charantia L. on Oxidative Stress and Pregnancy Rate in Infertile Cows

Introduction

The effect of intrauterine administration of Momordica charantia L. (MC) extract on oxidative changes and pregnancy rate in infertile cows was investigated.

Material and Methods

Endometrial smear specimens were taken from 40 cows with fertility problems for cytological examination, and the cows were randomly divided into two groups: group I (n = 20) was subjected to intrauterine administration of 40 mL (0.25 g/mL) of MC extract, group II (n = 20) was subjected to intrauterine administration of 40 mL of pure olive oil. Blood samples were taken starting from the day of administration of MC extract or olive oil (day 0) and then for three weeks at weekly intervals (days 7, 14, 21). Blood serum samples were evaluated for total antioxidant capacity (TAS), total oxidant level (TOS), oxidative stress index (OSI), lipid hydroperoxide (LOOH), and nitric oxide (NO) levels. In addition, on the 14^th day following treatment, two doses of PGF2α were administrated to all cows at 14-day intervals. Following the second PGF2α administration, insemination and GnRH administration was performed at the 60^th h after PGF2α treatment. Smear samples were stained with Giemsa and immunohistochemically to determine cytological changes and inflammatory status.

Results

According to cytological findings, subclinical endometritis was a prevalent disorder in cows with infertility problem (82.5%; 33/40). Additionally, 60.6% (20/33) of the cows with subclinical endometritis had acute inflammation, whereas remaining 13 cows had chronic endometritis. Of the cows with subclinical endometritis, 50% (8/16) and 35% (6/17) became pregnant in group I and II, respectively (P > 0.05). Although the oxidative stress parameters showed similarities between both groups (P > 0.05), there was a significant difference (P < 0.001) between the groups in terms of mean NO and LOOH levels (NO - 31.20 ± 11.38 vs 44.53 ± 11.50 μmol/L and LOOH - 1.22 ± 0.37 vs 1.89 ± 0.36 μmol/L).

Conclusion

The obtained results indicated that MC administration, especially in the presence of active inflammation, may improve the pregnancy rate by positive reduction of oxidative changes.

Bone morphogenetic protein 9 serves a protective role in response to ischemic‑reperfusion in the brain by promoting ERK activation

The aim of the present study was to investigate the expression and function mechanism of bone morphogenetic protein 9 (BMP9) in cerebral ischemia-reperfusion (I/R) injuries in vivo and in vitro. A total of 40 Sprague-Dawley rats were randomly divided into four groups (n=10): i) Normal control; ii) sham surgery group, the procedure without occlusion; iii) I/R group, right middle cerebral artery occlusion (MCAO) followed by reperfusion; and iv) adenoviral vector (Ad)-BMP9 + I/R group, Ad-BMP9 intracerebroventricular injection was performed 2 days prior to MCAO. Neurological deficit score and infarct volume were measured at 24 h following reperfusion. To further test the mechanism of BMP9, astrocytes were isolated and treated with Ad-BMP9, Ad-BMP9 + extracellular signal-regulated kinase (ERK) inhibitor PD098059, Ad-BMP9 + c-Jun N-terminal kinase inhibitor SP600125 and Ad-BMP9 + p38 inhibitor SB203580 for 24 h, followed by undergoing oxygen-glucose deprivation and reoxygenation (OGD/R) treatment. Cell viability and death were assessed by 3-(4,5-dimethylthiazol-2yl)-5-(3-carboxymethoxyphenyl)-(4-sulfophenyl)-2H-tetrazolium and lactate dehydrogenase release, respectively. Gene expression was determined by quantitative polymerase chain reaction and western blotting. BMP9 was identified to be upregulated at mRNA and protein levels in cerebral I/R animal and cell models. BMP9 pretreatment significantly reduced the neurological score and infarct volume compared with I/R rats. In astrocytes, overexpression of BMP9 significantly decreased cell death and improved cell viability, an effect which may be mediated by the ERK signaling pathway, as ERK was activated by BMP9 and the use of PD098059 partially reversed the protective effect of BMP9. Pretreatment with BMP-9 may be a promising treatment option for prevention of cerebral I/R injuries.

Recent Advances in Momordica charantia: Functional Components and Biological Activities

Momordica charantia L. (M. charantia), a member of the Cucurbitaceae family, is widely distributed in tropical and subtropical regions of the world. It has been used in folk medicine for the treatment of diabetes mellitus, and its fruit has been used as a vegetable for thousands of years. Phytochemicals including proteins, polysaccharides, flavonoids, triterpenes, saponins, ascorbic acid and steroids have been found in this plant. Various biological activities of M. charantia have been reported, such as antihyperglycemic, antibacterial, antiviral, antitumor, immunomodulation, antioxidant, antidiabetic, anthelmintic, antimutagenic, antiulcer, antilipolytic, antifertility, hepatoprotective, anticancer and anti-inflammatory activities. However, both in vitro and in vivo studies have also demonstrated that M. charantia may also exert toxic or adverse effects under different conditions. This review addresses the chemical constituents of M. charantia and discusses their pharmacological activities as well as their adverse effects, aimed at providing a comprehensive overview of the phytochemistry and biological activities of M. charantia.

CoQ10 Augments Rosuvastatin Neuroprotective Effect in a Model of Global Ischemia via Inhibition of NF-κB/JNK3/Bax and Activation of Akt/FOXO3A/Bim Cues

Statins were reported to lower the Coenzyme Q10 (CoQ10) content upon their inhibition of HMG-CoA reductase enzyme and both are known to possess neuroprotective potentials; therefore, the aim is to assess the possible use of CoQ10 as an adds-on therapy to rosuvastatin to improve its effect using global I/R model. Rats were allocated into sham, I/R, rosuvastatin (10 mg/kg), CoQ10 (10 mg/kg) and their combination. Drugs were administered orally for 7 days before I/R. Pretreatment with rosuvastatin and/or CoQ10 inhibited the hippocampal content of malondialdehyde, nitric oxide, and boosted glutathione and superoxide dismutase. They also opposed the upregulation of gp91^phox, and p47^phox subunits of NADPH oxidase. Meanwhile, both agents reduced content/expression of TNF-α, iNOS, NF-κBp65, ICAM-1, and MPO. Besides, all regimens abated cytochrome c, caspase-3 and Bax, but increased Bcl-2 in favor of cell survival. On the molecular level, they increased p-Akt and its downstream target p-FOXO3A, with the inhibition of the nuclear content of FOXO3A to downregulate the expression of Bim, a pro-apoptotic gene. Additionally, both treatments downregulate the JNK3/c-Jun signaling pathway. The effect of the combination regimen overrides that of either treatment alone. These effects were reflected on the alleviation of the hippocampal damage in CA1 region inflicted by I/R. Together, these findings accentuate the neuroprotective potentials of both treatments against global I/R by virtue of their rigorous multi-pronged actions, including suppression of hippocampal oxidative stress, inflammation, and apoptosis with the involvement of the Akt/FOXO3A/Bim and JNK3/c-Jun/Bax signaling pathways. The study also nominates CoQ10 as an adds-on therapy with statins.

Momordica charantia: a popular health-promoting vegetable with multifunctionality

Products derived from edible medicinal plants have been used for centuries to prevent, treat, and even cure multiple diseases. Momordica charantia L., widely cultivated around the world, is a typical one bred for vegetables and medicinal usage. All parts of M. charantia possess important medicinal properties, including antidiabetic, anticancer, hypotensive, anti-obesity, antimicrobial, antihyperlipidemic, antioxidant, anti-inflammatory, immuno-modulatory, anthelmintic, neuro-protective, as well as hepato-protective properties both in vitro and in vivo. This review summarizes the active components and medicinal properties of M. charantia, especially the activities and mechanisms of its anti-diabetic and anti-cancer properties. The anti-diabetic properties involve inhibiting intestinal α-glucosidase and glucose transport, protecting islet β-cells, enhancing insulin secretion, increasing hepatic glucose disposal, decreasing gluconeogenesis, and even ameliorating insulin resistance. Moreover, the expressions of PPARs could also be activated and up-regulated. Meanwhile, its anticancer properties are mostly due to apoptosis, cell cycle arrest, and expression of serum factors associated with immunity. In this review, we aim to provide an overview of M. charantia and its benefits for development as a functional food.

Protective effect of Momordica charantia water extract against liver injury in restraint-stressed mice and the underlying mechanism

Background: Momordica charantia is used in China for its jianghuo (heat-clearing and detoxifying) effects. The concept of shanghuo (the antonym of jianghuo, excessive internal heat) in traditional Chinese medicine is considered a type of stress response of the body. The stress process involves internal organs, especially the liver. Objective: We hypothesized that Momordica charantia water extract (MWE) has a hepatoprotective effect and can protect the body from stress. The aim of this study was to investigate the possible effects of MWE against liver injury in restraint-stressed mice. Design: The mice were intragastrically administered with MWE (250, 500 and 750 mg/kg bw) daily for 7 days. The Normal Control (NC) and Model groups were administered distilled water. A positive control group was intragastrically administered vitamin C 250 mg/kg bw. After the last administration, mice were restrained for 20 h. Results: MWE reduced the serum AST and ALT, reduced the NO content and the protein expression level of iNOSin the liver; significantly reduced the mitochondrial ROS content, increased the mitochondrial membrane potential and the activities of mitochondrial respiratory chain complexes I and II in restraint-stressed mice. Conclusions: The results indicate that MWE has a protective effect against liver injury in restraint-stressed mice. Abbreviations: MWE: Momordica charantia water extract; M. charantia: Momordica charantia L.; ROS: reactive oxygen species; NO: nitric oxide; iNOS: inducible nitric oxide synthase; IL-1β: interleukin-1 beta; TNF-α: tumor necrosis factor alpha; IL-6: interleukin 6; IFN-γ: interferon gamma; VC: vitamin C; ALT: alanine transaminase; AST: aspartate aminotransferase; GSH: glutathione; GSH-PX: glutathione peroxidase; MDA: malondialdehyde; BCA: bicinchoninic acid; TBARS: thiobarbituric acid reactive substances; Trolox: 6-hydroxy-2,5,7,8-tetramethylchroman-2-carboxylic acid; JC-B: Janus Green B; DW: dry weight; FC: Folin-Ciocalteu; GAE: gallic acid equivalents; bw: body weight; NC: normal control group; Model: restraint stress model group; VC: positive control vitamin C group, 250 mg/kg bw; MWEL: Momordica charantia water extract low-dose group, 250 mg/kg bw; MWEM: Momordica charantia water extract middle-dose group, 500 mg/kg bw; MWEH: Momordica charantia water extract high-dose group, 750 mg/kg bw; HE: hematoxylin and eosin; ORAC: total oxygen radical absorbance capacity; ABAP: dihydrochloride; ATP: adenosine triphosphate.

Clonidine preconditioning alleviated focal cerebral ischemic insult in rats via up-regulating p-NMDAR1 and down-regulating NMDAR2A / p-NMDAR2B

A brain ischemia rat model was established by middle cerebral artery occlusion (MCAO) for 2h and reperfusion for 4h to investigate the underlying mechanism of the neuroprotection action of clonidine, a classical alpha-2 adrenergic agonist, on cerebral ischemia. Clonidine and yohimbine were intraperitoneally given to the rats each day for a week before ischemia. Neurological deficits evaluations were carried out at 6h after operation. TTC staining method was used to measure the volume of brain infarction. Expression levels of NMDAR1, NMDAR2A, NMDAR2B were assayed by western blotting. Our data demonstrated that clonidine pretreatment significantly improved the neurological deficit scores and reduced the brain infarct volumes of the rats. Furthermore, protein expression level of p-NMDAR2B in cortex was significantly up-regulated whereas that of p-NMDAR1 was decreased when compared with the sham-operated rats. Remarkably, clonidine treatment led to significant down-regulation of p-NMDAR2B and NMDAR2A in addition to enhancement of the expression level of p-NMDAR1 in cortex. This is the first report illustrating the neuroprotective role of clonidine may be mediated through modulation of the expression levels of p-NMDAR2B, NMDAR2A and p-NMDAR1 during cerebral ischemia.

Caveolin-1 protects against hepatic ischemia/reperfusion injury through ameliorating peroxynitrite-mediated cell death

Nitrative stress is considered as an important pathological process of hepatic ischemia and reperfusion injury but its regulating mechanisms are largely unknown. In this study, we tested the hypothesis that caveolin-1 (Cav-1), a plasma membrane scaffolding protein, could be an important cellular signaling against hepatic I/R injury through inhibiting peroxynitrite (ONOO(-))-induced cellular damage. Male wild-type mice and Cav-1 knockout (Cav-1(-/-)) were subjected to 1h hepatic ischemia following 1, 6 and 12h of reperfusion by clipping and releasing portal vessels respectively. Immortalized human hepatocyte cell line (L02) was subjected to 1h hypoxia and 6h reoxygenation and treated with Cav-1 scaffolding domain peptide. The major discoveries included: (1) the expression of Cav-1 in serum and liver tissues of wild-type mice was time-dependently elevated during hepatic ischemia-reperfusion injury. (2) Cav-1 scaffolding domain peptide treatment inhibited cleaved caspase-3 expression in the hypoxia-reoxygenated L02 cells; (3) Cav-1 knockout (Cav-1(-/-)) mice had significantly higher levels of serum transaminases (ALT&AST) and TNF-α, and higher rates of apoptotic cell death in liver tissues than wild-type mice after subjected to 1h hepatic ischemia and 6hour reperfusion; (4) Cav-1(-/-) mice revealed higher expression levels of iNOS, ONOO(-) and 3-nitrotyrosine (3-NT) in the liver than wild-type mice, and Fe-TMPyP, a representative peroxynitrite decomposition catalyst (PDC), remarkably reduced level of ONOO(-) and 3-NT and ameliorated the serum ALT, AST and TNF-α levels in both wild-type and Cav-1(-/-) mice. Taken together, we conclude that Cav-1 could play a critical role in preventing nitrative stress-induced liver damage during hepatic ischemia-reperfusion injury.