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Recombinant milk fat globule-EGF factor-8 reduces oxidative stress via integrin ?3/nuclear factor erythroid 2-related factor 2/heme oxygenase pathway in subarachnoid hemorrhage rats.

ABSTRACT: Milk fat globule-EGF factor-8 (MFGE8) has been reported to be neuroprotective in ischemic stroke. However, the effects of MFGE8 in early brain injury after subarachnoid hemorrhage (SAH) have not been investigated. We investigated the role of MFGE8 in early brain injury and the potential mechanisms in antioxidation after SAH.Two dosages (1 ?g and 3.3 ?g) of recombinant human MFGE8 were injected intracerebroventricularly at 1.5 hours after SAH. SAH grades, neurological scores, and brain water content were measured at 24 and 72 hours. For mechanistic study, MFGE8 siRNA, integrin ?3 siRNA, and heme oxygenase (HO) inhibitor SnPP IX were used for intervention. The oxidative stress and expression of MFGE8, integrin ?3, HO-1, extracellular signal-regulated kinase, and nuclear factor erythroid 2-related factor 2 were measured by Western blots 24 hours after SAH.The expression of MFGE8 and HO-1 increased and peaked 24 hours after SAH. Administration of recombinant human MFGE8 decreased brain water content and improved neurological functions both at 24 hours and at 72 hours after SAH. Recombinant human MFGE8 reduced oxidative stress and enhanced the expression of extracellular signal-regulated kinase, nuclear factor erythroid 2-related factor 2, and HO-1; and the effects were abolished by integrin ?3 siRNA and HO inhibitor SnPP IX.Recombinant MFGE8 attenuated oxidative stress that may be mediated by integrin ?3/nuclear factor erythroid 2-related factor 2/HO pathway after SAH. Recombinant MFGE8 may serve as an alternative treatment to ameliorate early brain injury for SAH patients.

SUBMITTER: Liu F

PROVIDER: S-EPMC4245320 | biostudies-literature | 2014 Dec

REPOSITORIES: biostudies-literature

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Recombinant milk fat globule-EGF factor-8 reduces oxidative stress via integrin β3/nuclear factor erythroid 2-related factor 2/heme oxygenase pathway in subarachnoid hemorrhage rats.

Liu Fei F Hu Qin Q Li Bo B Manaenko Anatol A Chen Yujie Y Tang Junjia J Guo Zongduo Z Tang Jiping J Zhang John H JH

Stroke 20141023 12

<h4>Background and purpose</h4>Milk fat globule-EGF factor-8 (MFGE8) has been reported to be neuroprotective in ischemic stroke. However, the effects of MFGE8 in early brain injury after subarachnoid hemorrhage (SAH) have not been investigated. We investigated the role of MFGE8 in early brain injury and the potential mechanisms in antioxidation after SAH.<h4>Methods</h4>Two dosages (1 μg and 3.3 μg) of recombinant human MFGE8 were injected intracerebroventricularly at 1.5 hours after SAH. SAH gr ...[more]

PMID: 25342030

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Project description:Subarachnoid hemorrhage is a specific, life-threatening form of hemorrhagic stroke linked to high morbidity and mortality. It has been found that the choroid plexus of the brain ventricles forming the blood-cerebrospinal fluid barrier plays an important role in subarachnoid hemorrhage pathophysiology. Heme oxygenase-1 and biliverdin reductase are two of the key enzymes of the hemoglobin degradation cascade. Therefore, the aim of present study was to investigate changes in protein levels of heme oxygenase-1 and biliverdin reductase in the rat choroid plexus after experimental subarachnoid hemorrhage induced by injection of non-heparinized autologous blood to the cisterna magna. Artificial cerebrospinal fluid of the same volume as autologous blood was injected to mimic increased intracranial pressure in control rats. Immunohistochemical and Western blot analyses were used to monitor changes in the of heme oxygenase-1 and biliverdin reductase levels in the rat choroid plexus after induction of subarachnoid hemorrhage or artificial cerebrospinal fluid application for 1, 3, and 7 days. We found increased levels of heme oxygenase-1 and biliverdin reductase protein in the choroid plexus over the entire period following subarachnoid hemorrhage induction. The level of heme oxygenase-1 was the highest early (1 and 3 days) after subarachnoid hemorrhage indicating its importance in hemoglobin degradation. Increased levels of heme oxygenase-1 were also observed in the choroid plexus epithelial cells at all time points after application of artificial cerebrospinal fluid. Biliverdin reductase protein was detected mainly in the choroid plexus epithelial cells, with levels gradually increasing during subarachnoid hemorrhage. Our results suggest that heme oxygenase-1 and biliverdin reductase are involved not only in hemoglobin degradation but probably also in protecting choroid plexus epithelial cells and the blood-cerebrospinal fluid barrier from the negative effects of subarachnoid hemorrhage.

Project description:Accumulating evidence suggests neuronal apoptosis has the potential to lead to more harmful effects in the pathological processes following traumatic brain injury (TBI). Previous studies have established that milk fat globule-EGF factor-8 (MFG-E8) provides neuroprotection through modulation of inflammation, oxidative stress, and especially apoptosis in cerebral ischemia and neurodegenerative disease. However, the effects of MFG-E8 on neuronal apoptosis in TBI have not yet been investigated. Therefore, we explored the role of MFG-E8 on anti-apoptosis and its potential mechanism following TBI. In the first set of experiments, adult male Sprague-Dawley (SD) rats were randomly divided into Sham and TBI groups that were each further divided into five groups representing different time points (6?h, 24?h, 72?h, and 7 days) (n?=?9 each). Western blotting, quantitative real-time PCR, and immunofluorescence staining were performed to identify the expression and cellular localization of MFG-E8. In the second set of experiments, four groups were randomly assigned: Sham group, TBI?+?Vehicle group, and TBI?+?rhMFG-E8 (1 and 3?µg) (n?=?15). Recombinant human MFGE8 (rhMFG-E8) was administrated as two concentrations through intracerebroventricular (i.c.v.) injection at 1?h after TBI induction. Brain water content, neurological severity score, western blotting, and immunofluorescence staining were measured at 24 and 72?h following TBI. In the final set of experiments, MFG-E8 siRNA (500?pmol/3?µl), integrin ?3 siRNA (500?pmol/3?µl), and PI3K inhibitor LY294002 (5 and 20?µM) were injected i.c.v. and thereafter rats exposed to TBI. Western blotting, immunofluorescence staining, brain water content, neurological severity score, and Fluoro-Jade C (FJC) staining were used to investigate the effect of the integrin-?3/FAK/PI3K/AKT signaling pathway on MFG-E8-mediated anti-apoptosis after TBI. The expression of MFG-E8 was mainly located in microglial cells and increased to peak at 24?h after TBI. Treatment with rhMFG-E8 (3?µg) markedly decreased brain water content, improved neurological deficits, and reduced neuronal apoptosis at 24 and 72?h after TBI. rhMFG-E8 significantly enhanced the expression of integrin-?3/FAK/PI3K/AKT pathway-related components. Administration of integrin-?3 siRNA and LY294002 (5 and 20?µM) abolished the effect of rhMFG-E8 on anti-apoptosis and neuroprotection after TBI. This study demonstrated for the first time that rhMFG-E8 inhibits neuronal apoptosis and offers neuroprotection. This is suggested to occur through the modulation of the integrin-?3/FAK/PI3K/AKT signaling pathway, highlighting rhMFG-E8 as a potentially promising therapeutic strategy for TBI patients.

Dataset Information

Recombinant milk fat globule-EGF factor-8 reduces oxidative stress via integrin ?3/nuclear factor erythroid 2-related factor 2/heme oxygenase pathway in subarachnoid hemorrhage rats.

Publications

Recombinant milk fat globule-EGF factor-8 reduces oxidative stress via integrin β3/nuclear factor erythroid 2-related factor 2/heme oxygenase pathway in subarachnoid hemorrhage rats.

Similar Datasets

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