Despite the characterization of neuroprotection by transforming growth factor-beta1 (TGF-beta1), the signaling pathway mediating its protective effect is unclear. Bad is a proapoptotic member of the Bcl-2 family and is inactivated on phosphorylation via mitogen-activated protein kinase (MAPK). This study attempted to address whether MAPK signaling and Bad phosphorylation were influenced by TGF-beta1 and, furthermore, whether these two events were involved in the antiapoptotic effect of TGF-beta1. We found a gradual activation of extracellular signal-regulated kinase 1/2 (Erk1/2) and MAPK-activated protein kinase-1 (also called Rsk1) and a concomitant increase in Bad phosphorylation at Ser(112) in mouse brains after adenovirus-mediated TGF-beta1 transduction under nonischemic and ischemic conditions induced by transient middle cerebral artery occlusion. Consistent with these effects, the ischemia-induced increase in Bad protein level and caspase-3 activation were suppressed in TGF-beta1-transduced brain. Consequently, DNA fragmentation, ischemic lesions, and neurological deficiency were significantly reduced. In cultured rat hippocampal cells, TGF-beta1 inhibited the increase in Bad expression caused by staurosporine. TGF-beta1 concentration- and time-dependently activated Erk1/2 and Rsk1 accompanied by an increase in Bad phosphorylation. These effects were blocked by U0126, a mitogen-activated protein kinase/Erk kinase 1/2 inhibitor, suggesting an association between Bad phosphorylation and MAPK activation. Notably, U0126 and a Rsk1 inhibitor (Ro318220) abolished the neuroprotective activity of TGF-beta1 in staurosporine-induced apoptosis, indicating that activation of MAPK is necessary for the antiapoptotic effect of TGF-beta1 in cultured hippocampal cells. Together, we demonstrate that TGF-beta1 suppresses Bad expression under lesion conditions, increases Bad phosphorylation, and activates the MAPK/Erk pathway, which may contribute to its neuroprotective activity.
M2 macrophages was domesticated by tumor microenvironment to produce some angiogenic molecules and protease, facilitating angiogenesis and matrix breakdown, promoting tumor invasive and metastasis. However, The function of M2 macrophages to progression of esophageal carcinoma, especially Kazakh esophageal carcinoma is still dimness. This study aims to investigate M2 macrophages correlated with matrix metalloproteinase-9 (MMP9) and microvessel density, and the role in the progression of Kazakh esophageal squamous cell carcinoma. CD163 and CD34 as the marker of M2 macrophages and endothelial cells, were used to identify the M2 macrophages density and microvessel density, respectively. Immunohistochemistry staining was evaluated the expression of MMP9. The number of infiltrated CD163-positive M2 macrophages in tumor islets and stroma was significantly higher than in cancer adjacent normal tissues. The increased of M2 macrophages and microvessel density were significantly correlated with more malignant phenotypes including lymph node metastasis and clinical stage progression. Meanwhile, the expression of MMP9 showed much higher level in esophageal squamous cell carcinoma than that in cancer adjacent normal tissues, and high expression of MMP9 in Kazakh esophageal squamous cell carcinoma was significantly associated with age, depth of tumor invasion, lymph node metastasis, and tumor clinical stage. The quantity of M2 macrophages in tumor stroma was positively associated with microvessel density and the expression of MMP9, and as an independent poorly prognostic factor for overall survival time of Kazakh esophageal squamous cell carcinoma. These findings suggest the increased number of M2 macrophages correlated with high expression of MMP9 and high microvessel density may contribute to the tumor aggressiveness and angiogenesis, promoting the progression of Kazakh esophageal squamous cell carcinoma.
Background and Purpose-Chemokines have been shown to play an important role in leukocyte and monocyte/macrophage infiltration into ischemic regions. The purpose of this study is to identify whether overexpression of the active human transforming growth factor-1 (ahTGF-1) can downregulate expression of monocyte chemoattractant protein-1 (MCP-1), macrophage inflammatory protein-1␣ (MIP-1␣), and intercellular adhesion molecule-1 (ICAM-1) and reduce ischemic brain injury. Methods-Overexpression of transforming growth factor-1 (TGF-1) was achieved through adenoviral gene transfer.Five days after adenoviral transduction, the mouse underwent 30 minutes of middle cerebral artery occlusion followed by 1 to 7 days of reperfusion. TGF-1, MCP-1, MIP-1␣, and ICAM-1 were detected by enzyme-linked immunosorbent assay and immunohistochemistry. Infarct areas and volumes were measured by cresyl violet staining. Results-MCP-1 and MIP-1␣ expression is increased after middle cerebral artery occlusion, and double-labeled immunostaining revealed that MCP-1 is colocalized with neurons and astrocytes. Viral-mediated TGF-1 overexpression was significantly greater at measured time points, with a peak at 7 to 9 days. The expression of MCP-1 and MIP-1␣, but not ICAM-1, was reduced in the mice overexpressing ahTGF-1 (PϽ0.05). Furthermore, infarct volume was significantly reduced in the mice overexpressing ahTGF-1 (PϽ0.05). Conclusions-This
Both bombesin and epidermal growth factor (EGF) are potent mitogens in Swiss 3T3 cells that nonetheless have dissimilar receptor structures. To explore possible common intracellular events involved in the stimulation of cellular growth by these two peptides, we have evaluated the regulation of the mitogen-activated protein (MAP) kinase. Exposure of Swiss 3T3 cells to bombesin, EGF or the protein kinase C activator phorbol 12-myristate 13-acetate (PMA) causes the rapid and transient stimulation of the enzyme activity. Pretreatment of cells with the protein kinase inhibitor H-7, or down-regulation of cellular protein kinase C by prolonged exposure to PMA, causes a decrease of over 90% in the activation of MAP kinase by bombesin. In contrast, these treatments have no effect on the stimulation of MAP kinase by EGF. The stimulation of MAP kinase activity by bombesin is dose-dependent, occurring over a narrow concentration range of the peptide. Both EGF and bombesin stimulate the phosphorylation of an immunoprecipitable MAP kinase protein migrating at 42 kDa on SDS/PAGE. Phosphoamino acid analysis of this phosphorylated protein reveals that EGF and bombesin stimulate phosphorylation on tyrosine, threonine and serine residues. Tyrosine phosphorylation of the enzyme, as evaluated by antiphosphotyrosine blotting of the immunoprecipitated protein, reveals that the time course of phosphorylation by both mitogens correlates with stimulation of enzyme activity. These results provide further evidence for the convergence of discrete pathways emanating from tyrosine kinase and G-protein-linked receptors in the regulation of MAP kinase.
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