gw9662 and Stroke

Neuroinflammation plays an important role in the pathophysiological process of acute cerebral infarction, which may aggravate brain injury and hinder neuro-repair. Microglia are innate immune cells in the brain. Ginkgetin has anti-inflammatory and neuroprotective effects, but the mechanism remains unclear. This study aims to explore the regulatory effects of ginkgetin on microglia polarization in brain ischemia. Oxygen glucose deprivation (OGD) cellular model and middle cerebral artery occlusion (MCAO) animal model was used in this study. We first observed the dynamic process of microglia polarization in ischemic stroke, and then investigated the effect of ginkgetin treatment on microglia polarization. Finally, we studied the role of PPARγ signaling pathway and the blocking effect of PPARγ antagonist GW9662 in this process. OGD and cerebral ischemia polarized microglia mainly to M1 type. However, ginkgetin treatment converted microglia from M1 type to M2 type, inhibited neuroinflammation, and exerted neuronal protective effects. PPARγ signaling pathway was activated during this process. The above effects could be blocked by GW9662. Ginkgetin can promote M2 polarization of microglia through PPARγ signaling pathway, thereby inhibiting neuroinflammation and promoting recovery of neurological functions in ischemic stroke.

Topics: Anilides; Animals; Biflavonoids; Brain Ischemia; Infarction, Middle Cerebral Artery; Ischemic Stroke; Microglia; Neuroprotection; PPAR gamma; Stroke

Delayed thrombolytic therapy with recombinant tissue plasminogen activator (tPA) may exacerbate blood-brain barrier (BBB) breakdown after ischemic stroke and lead to catastrophic hemorrhagic transformation (HT). Rosiglitazone(RSG), a widely used antidiabetic drug that activates peroxisome proliferator-activated receptor-γ (PPAR-γ), has been shown to protect against cerebral ischemia through promoting poststroke microglial polarization toward the beneficial anti-inflammatory phenotype. However, whether RSG can alleviate HT after delayed tPA treatment remains unknown. In this study, we sort to examine the role of RSG on tPA-induced HT after stroke.. We used the murine suture middle cerebral artery occlusion (MCAO) models of stroke followed by delayed administration of tPA (10 mg/kg, 2 hours after suture occlusion) to investigate the therapeutic potential of RSG against tPA-induced HT. When RSG(6 mg/kg) was intraperitoneally administered 1 hour before MCAO in tPA-treated MCAO mice, HT in the ischemic territory was significantly attenuated 1 day after stroke. In the tPA-treated MCAO mice, we found RSG significantly mitigated BBB disruption and hemorrhage development compared to tPA-alone-treated stroke mice. Using flow cytometry and immunostaining, we confirmed that the expression of CD206 was significantly upregulated while the expression of iNOS was down-regulated in microglia of the RSG-treated mice. We further found that the expression of Arg-1 was also upregulated in those tPA and RSG-treated stroke mice and the protection against tPA-induced HT and BBB disruption in these mice were abolished in the presence of PPAR-γ antagonist GW9662 (4 mg/kg, 1 hour before dMCAO through intraperitoneal injection).. RSG treatment protects against BBB damage and ameliorates HT in delayed tPA-treated stroke mice by activating PPAR-γ and favoring microglial polarization toward anti-inflammatory phenotype.

Topics: Anilides; Animals; Anti-Inflammatory Agents; Blood-Brain Barrier; Hypoglycemic Agents; Infarction, Middle Cerebral Artery; Injections, Intraperitoneal; Intracranial Hemorrhages; Lectins, C-Type; Male; Mannose Receptor; Mannose-Binding Lectins; Mice; Mice, Inbred C57BL; Nitric Oxide Synthase Type II; Plasminogen Activators; PPAR gamma; Receptors, Cell Surface; Rosiglitazone; Stroke; Tissue Plasminogen Activator

It is known that cerebral ischemia can cause brain inflammation and adiposome can serve as a depot of inflammatory mediators. In the study, the pro-inflammatory and pro-death role of adiposome in ischemic microglia and ischemic brain was newly investigated. The contribution of PPARγ to adiposome formation was also evaluated for the first time in ischemic microglia. Focal cerebral ischemia/reperfusion (I/R) animal model and the in vitro glucose-oxygen-serum deprivation (GOSD) cell model were both applied in the study. GOSD- or I/R-induced adiposome formation, inflammatory activity, cell death of microglia, and brain infarction were, respectively, determined, in the absence or presence of NS-398 (adiposome inhibitor) or GW9662 (PPARγ antagonist). GOSD-increased adiposome formation played a critical role in stimulating the inflammatory activity (production of TNF-α and IL-1β) and cell death of microglia. Similar results were also found in ischemic brain tissues. GOSD-induced PPARγ partially contributed to the increase of adiposomes and adiposome-mediated inflammatory responses of microglia. Blockade of adiposome formation with NS-398 or GW9662 significantly reduced not only the inflammatory activity and death rate of GOSD-treated microglia but also the brain infarct volume and motor function deficit of ischemic rats. The pathological role of microglia-derived adiposome in cerebral ischemia has been confirmed and attributed to its pro-inflammatory and/or pro-death effect upon ischemic brain cells and tissues. Adiposome and its upstream regulator PPARγ were therefore as potential targets for the treatment of ischemic stroke. Therapeutic values of NS-398 and GW9662 have been suggested.

Topics: Anilides; Animals; Animals, Newborn; Brain Ischemia; Cell Death; Culture Media, Serum-Free; Cyclooxygenase 2; Down-Regulation; Glucose; Inflammation; Interleukin-1beta; Lipid Droplets; Male; Microglia; Motor Activity; Neurons; Nitrobenzenes; Oxygen; PPAR gamma; Rats, Sprague-Dawley; Reperfusion Injury; Stroke; Sulfonamides; Tumor Necrosis Factor-alpha

It has been shown that the calcium antagonist nifedipine upregulates superoxide dismutase (SOD). Although the peroxisome proliferator-activated receptor (PPAR) response element is located in the promoter region of Cu/ZnSOD, it remains unclear whether nifedipine upregulates PPARs and inhibits vascular remodeling. We hypothesthized that nifedipine activates PPARgamma, inhibits vascular remodeling, and improves vascular function in hypertension.. Stroke-prone spontaneously hypertensive rats (SHRSP) were treated with vehicle, nifedipine, and PPARgamma selective antagonist GW9662 with nifedipine.. Systolic blood pressure in the three SHRSP groups was higher (p <0.01), and the left ventricular weight/body weight ratio was greater (p <0.01) than in the Wistar-Kyoto rat (WKY) group with no differences observed among the three SHRSP groups. In the SHRSP heart, nifedipine significantly inhibited intramyocardial arterial remodeling and perivascular fibrosis, and reduced oxidative stress, while it significantly restored adiponectin and the smooth muscle cell (SMC) phenotype, and selectively restored PPARgamma and Cu/ZnSOD expression/activities to their levels in the WKY rat heart. Furthermore, nifedipine induced a dose-dependent increase in PPARgamma expression in cultured vascular SMCs. These effects of nifedipine were completely abolished by the co-administration of GW9662 with nifedipine. Nifedipine treatment significantly improved acetylcholine-induced relaxation by 27% compared with the vehicle SHRSP group, but it was still significantly impaired by 20% compared with the WKY group.. Nifedipine may inhibit vascular remodeling and improve vascular function by selective activation of PPARgamma through the activation of Cu/ZnSOD in hypertension.

Topics: Anilides; Animals; Aorta; Blood Pressure; Calcium Channel Blockers; Cells, Cultured; Endothelium, Vascular; Hypertension; Immunoblotting; Male; Mesenteric Arteries; Muscle, Smooth, Vascular; Nifedipine; Oxidative Stress; PPAR gamma; Rats; Rats, Inbred SHR; Rats, Inbred WKY; Stroke; Superoxide Dismutase; Superoxides

Phytoestrogens are considered to be natural selective estrogen receptor modulators exerting antioxidant activity and improving vascular function. However, the mechanisms responsible for their antioxidative effects remain largely unknown. This study tested the hypothesis that genistein may provide significant endothelial protection by antioxidative effects through attenuating NADPH oxidase expression and activity. The results showed that genistein suppressed the expressions of the p22phox NADPH oxidase subunit and angiotensin II (Ang II) type 1 (AT1) receptor in a concentration- and time-dependent manner in aortic endothelial cells from stroke-prone spontaneously hypertensive rats examined by Western blot analysis. Treatment with genistein also remarkably reduced the Ang II-induced superoxide by the reduction of nitroblue tetrazolium, inhibited nitrotyrosine formation, and attenuated endothelin-1 production by ELISA via the stimulation of Ang II. However, when cells were pretreated with ICI-182780, an estrogen-receptor antagonist, at a concentration of 50 micromol/l for 30 min and then co-incubated with ICI-182780 and genistein for 24 h, the inhibitory effect of genistein was not blocked. In contrast, the inhibitory effect of genistein treatment was partially reversed by 30-min pretreatment of endothelial cells with GW9662, a peroxisome proliferator-activated receptor gamma (PPARgamma) antagonist. Genistein thus appears to act as an antioxidant at the transcription level by the downregulation of p22phox and AT1 receptor expression. Our data also showed that the PPARgamma pathway was involved, at least in part, in the inhibitory effect of genistein on the expression of p22phox and AT1 receptors. The endothelial-protective effects of phytoestrogen may contribute to improvement of cardiovascular functions.

Topics: Angiotensin II; Anilides; Animals; Aorta, Thoracic; Cells, Cultured; Endothelin-1; Endothelium, Vascular; Enzyme Inhibitors; Estradiol; Estrogen Antagonists; Fulvestrant; Genistein; Hypertension; Male; Membrane Transport Proteins; NADPH Dehydrogenase; NADPH Oxidases; Phosphoproteins; PPAR gamma; Rats; Rats, Inbred SHR; Receptor, Angiotensin, Type 1; Signal Transduction; Stroke; Superoxides; Tyrosine; Vasoconstrictor Agents