scholarly journals Attenuation of astrogliosis and modulation of endothelial growth factor receptor in lipid rafts by simvastatin after traumatic brain injury

2010 ◽  
Vol 113 (3) ◽  
pp. 591-597 ◽  
Author(s):  
Hongtao Wu ◽  
Asim Mahmood ◽  
Dunyue Lu ◽  
Hao Jiang ◽  
Ye Xiong ◽  
...  
Keyword(s):  
Traumatic Brain Injury ◽  
Brain Injury ◽  
Growth Factor ◽  
Western Blot ◽  
Lipid Rafts ◽  
Blot Analysis ◽  
Western Blot Analysis ◽  
Growth Factor Receptor ◽  
Astrocyte Activation ◽  
Caveolin 1

Object The authors' previous studies have demonstrated that simvastatin treatment promotes neuronal survival and reduces inflammatory cytokine release from astrocytes after traumatic brain injury (TBI) in rats. Since reactive astrocytes produce inflammation mediators, in the current study the authors investigated the effect of simvastatin on astrocyte activation after TBI and its underlying signaling mechanisms. Methods Saline or simvastatin (1 mg/kg) was orally administered to rats starting at Day 1 after TBI and then daily for 14 days. Rats were killed at 1, 3, 7, and 14 days after treatment. Brain sections and tissues were prepared for immunohistochemical staining and Western blot analysis, respectively. Cultured astrocytes were subjected to oxygen-glucose deprivation (OGD) and followed by immunocytochemical staining with glial fibrillary acidic protein/caveolin-1 and Western blot analysis. Lipid rafts were isolated from the cell lysate and Western blotting was carried out to detect the changes in epidermal growth factor receptor (EGFR) expression and phosphorylation in the lipid rafts. Results Simvastatin significantly promoted neuronal survival after TBI and attenuated activation of astrocytes. Simvastatin modified the caveolin-1 expression in lipid rafts in astrocyte cell membrane, suppressed the phosphorylation of EGFR in lipid rafts of astrocytes after OGD, and inhibited the OGD-induced interleukin-1 production. Conclusions These data suggest that simvastatin reduces reactive astrogliosis and rescues neuronal cells after TBI. These beneficial effects of simvastatin may be mediated by inhibiting astrocyte activation after TBI through modifying the caveolin-1 expression in lipid rafts and the subsequent modulation of EGFR phosphorylation in lipid rafts.

Rhamnazin Ameliorates Traumatic Brain Injury in Mice via Reduction in Apoptosis, Oxidative Stress, and Inflammation

2021 ◽  
pp. 1-8
Author(s):  
Boxiao Yang ◽  
Rui Zhang ◽  
Qire Sa ◽  
Yanli Du
Keyword(s):  
Oxidative Stress ◽  
Traumatic Brain Injury ◽  
Flow Cytometry ◽  
Brain Injury ◽  
Western Blot ◽  
Protective Effect ◽  
Blot Analysis ◽  
Western Blot Analysis ◽  
Neuronal Degeneration ◽  
Flow Cytometry Analysis

<b><i>Background:</i></b> Traumatic brain injury (TBI) is posing serious health challenges for people across the globe due to high morbidity and mortality. However, none of the agents prevents or limits the damage caused by TBI because of its multifactorial etiology. Thus, the discovery of novel agents which can act via several pathways could serve the purpose and afford favorable consequence against TBI. Therefore, in the present article, we intended to investigate the protective effect of rhamnazin (RMZ), a dimethoxyflavone against experimentally induced TBI in mice. <b><i>Methods:</i></b> The effect of RMZ was investigated on cerebral edema and grip test score after induction of experimental brain injury in rats. The effect of RMZ was also investigated on neuronal degeneration in brain tissues of the experimental mice via Nissl staining and flow cytometry analysis. The expression of Bax and Bcl-2 was also quantified using Western blot analysis. The level of inflammatory cytokines (TNF-α and IL-1β) and oxidative stress markers (malondialdehyde, superoxide dismutase, and glutathione peroxidase) was also determined using enzyme-linked immunosorbent assay. <b><i>Results:</i></b> RMZ showed a significant reduction in edema and improved grip strength. It also prevented neuronal degeneration via inhibition of neuronal apoptosis as shown by flow cytometry analysis. RMZ showed an antiapoptotic effect via reduction of Bax and increased the expression of Bcl-2 in Western blot analysis. It also showed to inhibit oxidative stress and inflammation compared to the TBI group. <b><i>Conclusion:</i></b> Collectively, our study is first to demonstrate the protective effect of RMZ against experimentally induced TBI in rats.

Endosomal trafficking of the EGFR mutant, EGFRvIII, results in exosomal secretion that triggers astrocyte reactivity

2019 ◽  
Author(s):  
Kimiya Memarzadeh ◽  
Anthony N Patrizz ◽  
Edward C. Koellhoffer ◽  
Monica Gireud-Goss ◽  
Andrew Bean
Keyword(s):  
Plasma Membrane ◽  
Tumor Microenvironment ◽  
Western Blot ◽  
Blot Analysis ◽  
Western Blot Analysis ◽  
Growth Factor Receptor ◽  
Endosomal Trafficking ◽  
Protein Marker ◽  
Patient Prognosis ◽  
Egfr Mutant

Abstract Background: The epidermal growth factor receptor (EGFR) variant three (EGFRvIII) mutation is linked with approximately one third of Glioblastoma Multiforme (GBM) tumors and is associated with poor patient prognosis. Persistent signaling due to a lack of the EGFR ectodomain and inefficient degradation have been suggested to underlie the tumorgenic properties of EGFRvIII. Methods: Cell viability and trans-well migration assays were used to determine the effects that expression of the oncoprotein, EGFRvIII, had on glioma cells. A cell-free reconstitution assay developed by our laboratory was utilized to determine trafficking of EGFR and EGFRvIII at the late endosome and determine molecular requirements for inward budding of proteins into the MVB. Western Blot Analysis and Nanosight Tracking Analysis were used to characterize exosomes by protein marker presence and vesicle size, respectively. Immunohistochemistry and Western Blot analysis were used to determine astrocyte reactivity marked by GFAP expression. Results: Like the parental EGFR, we observed that EGFRvIII is internalized into the intraluminal vesicles of late endosomes / multivesicular bodies (MVBs) but does not follow the canonical pathway by which wild-type EGFR is degraded following MVB fusion with lysosomes. These studies suggested that EGFRvIII is secreted on exosomes, the intraluminal vesicles that are secreted upon MVB fusion with the plasma membrane, suggested that EGFRvIII is localized in a subset of MVBs that preferentially fuse with the plasma membrane rather than with lysosomes which may account for its decreased degradation. Astrocytes are a component of the GBM tumor microenvironment with which tumor cells interact in a paracrine manner. EGFRvIII-containing exosomes derived from GBM cells induce changes in astrocytes that mimic reactive astrogliosis including an increase in glial fibrillary acidic protein (GFAP). Conclusions: These studies reveal novel aspects of the endocytic trafficking of EGFRvIII that underlie its reduced degradation and the mechanism by which it is packaged into exosomes for secretion. Moreover, EGFRvIII secretion on exosomes can facilitate changes in the tumor microenvironment to enable tumor growth.

scholarly journals Increased expression of transforming growth factor α precursors in acute experimental colitis in rats

Gut ◽  
1997 ◽  
Vol 41 (2) ◽  
pp. 195-202 ◽  
Author(s):  
P Hoffmann ◽  
J M Zeeh ◽  
J Lakshmanan ◽  
V S Wu ◽  
F Procaccino ◽  
...  
Keyword(s):  
Growth Factor ◽  
Western Blot ◽  
Blot Analysis ◽  
Western Blot Analysis ◽  
Colonic Mucosa ◽  
Transforming Growth Factor ◽  
Rat Colon ◽  
Ribonuclease Protection Assay ◽  
Transforming Growth Factor Α ◽  
Factor Α

Background and aim—Epidermal growth factor (EGF) and transforming growth factor α (TGF-α), members of the EGF family of growth factors, protect rat gastric and colonic mucosa against injury. Having shown previously that exogenously applied EGF protects rat colonic mucosa against injury, the aim of the present study was to evaluate the endogenously expressed ligand mediating the protective effect of EGF/TGF-α in vivo.Methods—In an experimental model of trinitrobenzene sulphonic acid (TNBS)/ ethanol induced colitis in rats EGF and TGF-α expression was evaluated using a ribonuclease protection assay, northern blot analysis, western blot analysis, and immunohistochemistry.Results—TGF-α mRNA increased 3–4 times at 4–8 hours after induction of colitis and returned to control levels within 24 hours. TGF-α immunoreactive protein with a molecular size of about 28 kDa representing TGF-α precursors increased markedly after induction of colitis with a peak at 8–12 hours. No fully processed 5.6 kDa TGF-α protein was detected in normal or inflamed colon tissue. Only a weak signal for EGF mRNA expression was detected in the rat colon and no EGF protein was observed by immunohistochemistry or western blot analysis.Conclusions—TGF-α precursors are the main ligands for the EGF receptor in acute colitis. It is hypothesised that TGF-α precursors convey the biological activity of endogenous TGF-α peptides during mucosal defence and repair.

scholarly journals Identification of Matrine as a Novel Regulator of the CXCR4 Signaling Axis in Tumor Cells

2020 ◽  
Vol 21 (13) ◽  
pp. 4731 ◽  
Author(s):  
Young Yun Jung ◽  
Jae-Young Um ◽  
Acharan S. Narula ◽  
Ojas A. Namjoshi ◽  
Bruce E. Blough ◽  
...  
Keyword(s):  
Western Blot ◽  
Tumor Cells ◽  
Blot Analysis ◽  
Western Blot Analysis ◽  
Cancer Metastasis ◽  
Growth Factor Receptor ◽  
Boyden Chamber ◽  
Potential Candidate ◽  
Mrna Levels ◽  
Mobility Shift

Matrine, a quinolizidine alkaloid, is commonly employed for treating various viral and inflammatory disorders. Here, we have evaluated matrine for its activity on C-X-C chemokine receptor type 4 (CXCR4) and matrix metalloproteinases (MMP-9/2) expression, and its potential to affect tumor metastasis and invasion. The effects of matrine on CXCR4, MMP-9/2, and nuclear factor κB (NF-κB) activation in lung (A549), prostate (DU145), and pancreas (MIA PaCa-2) cells were investigated by diverse techniques. The expression level of CXCR4 and MMP-9/2 was analyzed by western blot analysis and reverse transcription polymerase chain reaction. NF-κB activation was also evaluated by western blot analysis, electrophoretic mobility shift assay as well as immunocytochemical experiments. Furthermore, we monitored cell invasion and metastasis activities by wound healing and Boyden chamber assays. We noted that matrine induced a down-regulation of CXCR4 and MMP-9/2 at both protein and mRNA levels. In addition, matrine negatively regulated human epidermal growth factor receptor 2 (HER2) and C-X-C Motif Chemokine Ligand 12 (CXCL12)-induced CXCR4 expression. Moreover, NF-κB suppression by matrine led to inhibition of metastatic potential of tumor cells. Our results suggest that matrine can block the cancer metastasis through the negative regulation of CXCR4 and MMP-9/2 and consequently it can be considered as a potential candidate for cancer therapy.

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