The exact pathophysiological change concerning mitochondrial injury and oligodendrocyte apoptosis in MS and EAE model is still unknown. Whether curcumin is able to inhibit mitochondrial injury and suppress the apoptosis in the early stages of MS/EAE is still unclear. We first explored mitochondrial injury and apoptosis at different time points p.i. in C57 BL/6 EAE mice. We then explored the effects of curcumin on mitochondria and apoptosis. Results showed that mitochondrial injury can be observed 3 days p.i. Apoptosis in the spinal cord occurred 3 days p.i. and the apoptotic cells were shown to be oligodendrocytes and neuronal cells. Curcumin significantly reduced the number of apoptotic cells and inhibited the upregulation of cyt-c, caspase-9, and caspase-3 at 7 days p.i. in the EAE mice. These observations demonstrate that mitochondrial injury and oligodendrocyte/neuronal apoptosis occur in the early stages of EAE. Curcumin can inhibit apoptosis in EAE mice which maybe act through protection of mitochondrial injury and inhibition of the intrinsic apoptotic pathway.
Inflammation plays an important role in the pathophysiological process after carotid artery stenting (CAS). Monocyte is a significant source of inflammatory cytokines in vascular remodeling. Telmisartan could reduce inflammation. In our study, we first found that, after CAS, the serum IL-1β, IL-6, TGF-β, and MMP-9 levels were significantly increased, but only MMP-9 level was elevated no less than 3 months. Second, we established a new in vitro model, where THP-1 monocytes were treated with the supernatants of human umbilical vein endothelial cells (HUVECs) that were scratched by pipette tips, which mimics monocytes activated by mechanical injury of stenting. The treatment enhanced THP-1 cell adhesion, migration and invasion ability, and the phosphorylation of ERK1/2 and Elk-1 and MMP-9 expression were significantly increased. THP-1 cells pretreated with PD98095 (ERK1/2 inhibitor) attenuated the phosphorylation of ERK1/2 and Elk-1 and upregulation of MMP-9, while pretreatment with telmisartan merely decreased the phosphorylation of Elk-1 and MMP-9 expression. These results suggested that IL-1β, IL-6, TGF-β, and MMP-9 participate in the pathophysiological process after CAS. Our new in vitro model mimics monocytes activated by stenting. MMP-9 expression could be regulated through ERK1/2/Elk-1 pathway, and the protective effects of telmisartan after stenting are partly attributed to its MMP-9 inhibition effects via suppression of Elk-1.
Botulinum neurotoxin (BoNT) potently inhibits cholinergic signaling at the neuromuscular junction. The ideal countermeasures for BoNT exposure are monoclonal antibodies or BoNT antisera, which form BoNT-containing immune complexes that are rapidly cleared from the general circulation. Clearance of opsonized toxins may involve complement receptor-mediated immunoadherence to red blood cells (RBC) in primates or to platelets in rodents. Methods of enhancing immunoadherence of BoNT-specific antibodies may increase their potency in vivo. We designed a novel fusion protein (FP) to link biotinylated molecules to glycophorin A (GPA) on the RBC surface. The FP consists of an scFv specific for murine GPA fused to streptavidin. FP:mAb:BoNT complexes bound specifically to the RBC surface in vitro. In a mouse model of BoNT neutralization, the FP increased the potency of single and double antibody combinations in BoNT neutralization. A combination of two antibodies with the FP gave complete neutralization of 5,000 LD50 BoNT in mice. Neutralization in vivo was dependent on biotinylation of both antibodies and correlated with a reduction of plasma BoNT levels. In a post-exposure model of intoxication, FP:mAb complexes gave complete protection from a lethal BoNT/A1 dose when administered within 2 hours of toxin exposure. In a pre-exposure prophylaxis model, mice were fully protected for 72 hours following administration of the FP:mAb complex. These results demonstrate that RBC-targeted immunoadherence through the FP is a potent enhancer of BoNT neutralization by antibodies in vivo.
Ischemia/reperfusion (I/R) injury after middle cerebral artery occlusion (MCAO) induces detrimental processes such as oxidative stress, inflammation, and apoptosis. All parts of the neurovascular unit are involved in these pathological processes. Fibulin-5 is a 66-kD glycoprotein secreted by various vascular cells, including vascular smooth muscle cells (SMCs), fibroblasts, and endothelial cells. As an extracellular matrix protein involved in cell adhesion, fibulin-5 has been widely studied in tumor growth and invasion. However, the effects of fibulin-5 on brain injury following ischemia/reperfusion have not been reported. In this study, we examined the effect of overexpressed fibulin-5 on reactive oxygen species (ROS) production. Fibulin-5 overexpression attenuated ROS expression, which in turn decreased apoptosis and blood-brain barrier (BBB) permeability following MCAO and reperfusion. Fibulin-5 also improved neurological deficits but had no effect on infarction volume. T2-weighted MRI and electron microscopy further confirmed brain edema reduction and decreased BBB disruption in fibulin-5 overexpression recombinant adenovirus (Ad-FBLN) treated rats. In addition, tight junction protein occludin was significantly degraded and matrix metalloproteinase 9 (MMP-9) immunoreactivity was significantly increased. Fibulin-5-mediated ROS decrease was not due to increased total superoxide dismutase levels but was instead correlated with the activation of Rac-1 pathway. The findings highlight the importance of antioxidant mechanism underlying cerebral ischemia/reperfusion.
Minocycline has been recently implicated in protection against focal cerebral ischemia reperfusion (I/R), but the protective effects on neurobehavioral abnormalities remains contradictory. In the present study, we investigate whether minocycline improves axonal regeneration and neurological function recovery by inhibiting the expression of the repulsive guidance molecular A (RGMa) after focal cerebral ischemia reperfusion. Male Sprague-Dawley (SD) rats were subjected to occlusion of the right middle cerebral artery (MCAO) for 2 h and 3 mg kg⁻¹ minocycline was injected intravenously immediately after reperfusion twice a day for 14 days. The staircase test and modified neurological severity score (mNSS) were performed to evaluate functional outcome and blood-brain barrier (BBB) permeability was assessed by Evan's blue dye extravasation (EB) at the expected time point. The expression of RGMa in ischemic cortex was measured by immunohistochemical staining and Western blot 2 weeks after MCAO. Neurofilament protein 200 (NF-200) immunohistochemical staining was used to assess axonal damage. Treatment with minocycline at a dose of 3 mg kg⁻¹ via the caudal vein significantly reduced the extravasation of EB, elevated mNSS and improved forelimb motor function as assessed by the staircase test when compared to the I/R group (P < 0.05). Moreover, axonal regrowth was enhanced in the minocycline treatment group when compared to the I/R group (P < 0.05). In addition, minocycline significantly reduced the expression of RGMa protein 2 weeks after MCAO as assessed by both immunostaining and Western blot. Our studies suggest that early minocycline treatment promotes neurological functional recovery and axonal regeneration in rats after MCAO, which might be mediated by down-regulating RGMa expression.
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