Propyl gallate induces cell death and inhibits invasion of human trophoblasts by blocking the AKT and mitogen-activated protein kinase pathways

Protein kinase-mediated signaling cascades constitute the major route by which cells respond to their extracellular environment. Of these, three well-characterized mitogen-activated protein kinase (MAPK) signaling pathways are those that use the extracellular signal-regulated kinase (ERK1/2) or the stress-activated protein kinase (p38/SAPK2 or JNK/SAPK) pathways. Mitogenic stimulation of the MAPK-ERK1/2 pathway modulates the activity of many transcription factors, leading to biological responses such as proliferation and differentiation. In contrast, the p38/SAPK2 and JNK/SAPK (c-Jun amino-terminal kinase/stress-activated protein kinase) pathways are only weakly, if at all, activated by mitogens, but are strongly activated by stress stimuli. There is now a growing body of evidence showing that these kinase signaling pathways become activated following a variety of injury stimuli including focal cerebral ischemia. Whether their activation, however, is merely an epiphenomenon of the process of cell death, or is actually involved in the mechanisms underlying ischemia-induced degeneration, remains to be fully understood. This review provides an overview of the current understanding of kinase pathway activation following cerebral ischemia and discusses the evidence supporting a role for these kinases in the mechanisms underlying ischemia-induced cell death.

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Regulation of FAS Ligand Expression during Activation-Induced Cell Death in T Cells by p38 Mitogen-Activated Protein Kinase and C-Jun Nh2-Terminal Kinase

Journal of Experimental Medicine ◽

10.1084/jem.191.6.1017 ◽

2000 ◽

Vol 191 (6) ◽

pp. 1017-1030 ◽

Cited By ~ 67

Author(s):

Jian Zhang ◽

Jian-Xin Gao ◽

Kostantin Salojin ◽

Qing Shao ◽

Marsha Grattan ◽

...

Keyword(s):

T Cells ◽

Cell Death ◽

T Cell ◽

Protein Kinase ◽

P38 Mapk ◽

Fas Ligand ◽

Mitogen Activated Protein Kinase ◽

Fasl Expression ◽

Activation Induced Cell Death ◽

Mitogen Activated Protein

Activation-induced cell death (AICD) is a mechanism of peripheral T cell tolerance that depends upon an interaction between Fas and Fas ligand (FasL). Although c-Jun NH2-terminal kinase (JNK) and p38 mitogen-activated protein kinase (MAPK) may be involved in apoptosis in various cell types, the mode of regulation of FasL expression during AICD in T cells by these two MAPKs is incompletely understood. To investigate the regulatory roles of these two MAPKs, we analyzed the kinetics of TCR-induced p38 MAPK and JNK activity and their regulation of FasL expression and AICD. We report that both JNK and p38 MAPK regulate AICD in T cells. Our data suggest a novel model of T cell AICD in which p38 MAPK acts early to initiate FasL expression and the Fas-mediated activation of caspases. Subsequently, caspases stimulate JNK to further upregulate FasL expression. Thus, p38 MAPK and downstream JNK converge to regulate FasL expression at different times after T cell receptor stimulation to elicit maximum AICD.

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