Recombinant human MFG-E8 attenuates cerebral ischemic injury: Its role in anti-inflammation and anti-apoptosis

Abstract

Excessive inflammation and apoptosis contribute to the pathogenesis of ischemic stroke. MFG-E8 is a 66-kDa glycoprotein that has shown tissue protection in various models of organ injury. However, the potential role of MFG-E8 in cerebral ischemia has not been investigated. We found that levels of MFG-E8 protein in the brain were reduced at 24 h after cerebral ischemia. To assess the potential role of MFG-E8 in cerebral ischemia, adult male Sprague-Dawley rats were subjected to permanent middle cerebral artery occlusion (MCAO). At 1 h post-stroke onset, an intravenous administration of 1 ml saline as vehicle or 160 μg/kg BW recombinant human MFG-E8 (rhMFG-E8) as treatment was given. The optimal dose of rhMFG-E8 was obtained from previous dose-response organ protection in rat sepsis studies. Neurological scores were determined at 24 h and 48 h post-MCAO. Rats were sacrificed thereafter and brains rapidly removed and analyzed for infarct size, histopathology, and markers of inflammation and apoptosis. Compared with saline vehicle, rhMFG-E8 treatment led to significant decreases in sensorimotor and vestibulomotor deficits, and infarct size at 24 h and 48 h post-MCAO. Measures associated with improved outcome included reduced microglial inflammatory cytokine secretion, adhesion molecules and neutrophil influx, cleaved caspase-3, and upregulation of peroxisome proliferator activated receptor-γ (PPAR-γ), and Bcl-2/Bax ratio leading to decreased apoptosis. Thus, rhMFG-E8 treatment is neuroprotective against cerebral ischemia through suppression of inflammation and apoptosis.

MFGE8 inhibits inflammasome-induced IL-1β production and limits postischemic cerebral injury

“…These results clearly indicate that endogenous MFGE8 is required for protection against excessive postischemic cerebral damage. We also found that supplementation of WT mice ( Figure 1C) with rMFGE8 induced a significant reduction of infarct volume, in agreement with the recently reported beneficial effect of recombinant human MFGE8 in a model of cerebral injury in rats (16).…”

“…MFGE8 expression has been associated with antiinflammatory effects in settings such as postischemic injury (16)(17)(18), experimental colitis (19), or sepsis (20). However, no particular antiinflammatory mechanism was identified, and the effects were indirectly related to the known role of MFGE8 in the clearance of apoptotic cells.…”

Recombinant human MFG-E8 ameliorates colon damage in DSS- and TNBS-induced colitis in mice

“…It is also possible that the human form of MFG-E8 may be less potent in the mouse, as the homology between human and mouse MGF-E8 is only 56%. Nevertheless, rhMFG-E8 is clearly active in rodents, as we have demonstrated previously [31][32][33][34][35] and in the present study. Therefore, rhMFG-E8 is expected to have comparable beneficial effects in humans with IBD.…”

“…[31][32][33][34][35] We have injected mice with up to 2560 μg/kg rhMFG-E8 intravenously, and observed no alteration in liver transaminases (AST and ALT) 24 h later (unpublished observations). More comprehensive studies, however, will need to be conducted to exclude any toxicity.…”

Human Milk Glycoproteins Protect Infants Against Human Pathogens

“…Indeed, a recent report indicates that recombinant lactadherin may attenuate sepsis-induced apoptosis. 103 Lactadherin interacts with damaged intestinal epithelium in vivo and plays an important role in stimulating growth of intestinal epithelial cells in vitro. 104 Thus, orally ingested lactadherin could have potential in the prevention and treatment of intestinal injury in infants.…”