scholarly journals Glycogen Synthase Kinase 3 Activation Is Important for Anthrax Edema Toxin-Induced Dendritic Cell Maturation and Anthrax Toxin Receptor 2 Expression in Macrophages

2011 ◽  
Vol 79 (8) ◽  
pp. 3302-3308 ◽  
Author(s):  
Jason L. Larabee ◽  
Francisco J. Maldonado-Arocho ◽  
Sergio Pacheco ◽  
Bryan France ◽  
Kevin DeGiusti ◽  
...  
Keyword(s):  
Dendritic Cell ◽  
Glycogen Synthase ◽  
Dominant Negative ◽  
Anthrax Toxin ◽  
Glycogen Synthase Kinase ◽  
Glycogen Synthase Kinase 3 ◽  
Cell Surface Expression ◽  
Luciferase Reporter ◽  
Edema Toxin ◽  
The Impact

ABSTRACTAnthrax edema toxin (ET) is one of two binary toxins produced byBacillus anthracisthat contributes to the virulence of this pathogen. ET is an adenylate cyclase that generates high levels of cyclic AMP (cAMP), causing alterations in multiple host cell signaling pathways. We previously demonstrated that ET increases cell surface expression of the anthrax toxin receptors (ANTXR) in monocyte-derived cells and promotes dendritic cell (DC) migration toward the lymph node-homing chemokine MIP-3β. In this work, we sought to determine if glycogen synthase kinase 3 (GSK-3) is important for ET-induced modulation of macrophage and DC function. We demonstrate that inhibition of GSK-3 dampens ET-induced maturation and migration processes of monocyte-derived dendritic cells (MDDCs). Additional studies reveal that the ET-induced expression of ANTXR in macrophages was decreased when GSK-3 activity was disrupted with chemical inhibitors or with small interfering RNA (siRNA) targeting GSK-3. Further examination of the ET induction of ANTXR revealed that a dominant negative form of CREB could block the ET induction of ANTXR, suggesting that CREB or a related family member was involved in the upregulation of ANTXR. Because CREB and GSK-3 activity appeared to be important for ET-induced ANTXR expression, the impact of GSK-3 on ET-induced CREB activity was examined in RAW 264.7 cells possessing a CRE-luciferase reporter. As with ANTXR expression, the ET induction of the CRE reporter was decreased by reducing GSK-3 activity. These studies not only provide insight into host pathways targeted by ET but also shed light on interactions between GSK-3 and CREB pathways in host immune cells.

scholarly journals Regulation of Ribosomal S6 Protein Kinase-p90rsk, Glycogen Synthase Kinase 3, and β-Catenin in Early Xenopus Development

1999 ◽  
Vol 19 (2) ◽  
pp. 1427-1437 ◽  
Author(s):  
Monica A. Torres ◽  
Hagit Eldar-Finkelman ◽  
Edwin G. Krebs ◽  
Randall T. Moon
Keyword(s):  
Cell Fate ◽  
Glycogen Synthase ◽  
Dominant Negative ◽  
Glycogen Synthase Kinase ◽  
Glycogen Synthase Kinase 3 ◽  
Fgf Signaling ◽  
Fgf Receptor ◽  
Multifunctional Protein ◽  
Downstream Target ◽  
Cytoplasmic Proteins

ABSTRACT β-Catenin is a multifunctional protein that binds cadherins at the plasma membrane, HMG box transcription factors in the nucleus, and several cytoplasmic proteins that are involved in regulating its stability. In developing embryos and in some human cancers, the accumulation of β-catenin in the cytoplasm and subsequently the nuclei of cells may be regulated by the Wnt-1 signaling cascade and by glycogen synthase kinase 3 (GSK-3). This has increased interest in regulators of both GSK-3 and β-catenin. Searching for kinase activities able to phosphorylate the conserved, inhibitory-regulatory GSK-3 residue serine 9, we found p90 rsk to be a potential upstream regulator of GSK-3. Overexpression of p90 rsk in Xenopus embryos leads to increased steady-state levels of total β-catenin but not of the free soluble protein. Instead, p90 rsk overexpression increases the levels of β-catenin in a cell fraction containing membrane-associated cadherins. Consistent with the lack of elevation of free β-catenin levels, ectopic p90 rsk was unable to rescue dorsal cell fate in embryos ventralized by UV irradiation. We show that p90 rsk is a downstream target of fibroblast growth factor (FGF) signaling during early Xenopus development, since ectopic FGF signaling activates both endogenous and overexpressed p90 rsk . Moreover, overexpression of a dominant negative FGF receptor, which blocks endogenous FGF signaling, leads to decreased p90 rsk kinase activity. Finally, we report that FGF inhibits endogenous GSK-3 activity inXenopus embryos. We hypothesize that FGF and p90 rsk play heretofore unsuspected roles in modulating GSK-3 and β-catenin.

scholarly journals Prion peptide induces neuronal cell death through a pathway involving glycogen synthase kinase 3

2003 ◽  
Vol 372 (1) ◽  
pp. 129-136 ◽  
Author(s):  
Mar PÉREZ ◽  
Ana I. ROJO ◽  
Francisco WANDOSELL ◽  
Javier DÍAZ-NIDO ◽  
Jesús AVILA
Keyword(s):  
Cell Death ◽  
Glycogen Synthase ◽  
Neuronal Cell Death ◽  
Neuroblastoma Cells ◽  
Neuronal Cell ◽  
Dominant Negative ◽  
Glycogen Synthase Kinase ◽  
Glycogen Synthase Kinase 3 ◽  
Dominant Negative Mutant ◽  
Neuronal Cultures

Prion diseases are characterized by neuronal cell death, glial proliferation and deposition of prion peptide aggregates. An abnormal misfolded isoform of the prion protein (PrP) is considered to be responsible for this neurodegeneration. The PrP 106–126, a synthetic peptide obtained from the amyloidogenic region of the PrP, constitutes a model system to study prion-induced neurodegeneration as it retains the ability to trigger cell death in neuronal cultures. In the present study, we show that the addition of this prion peptide to cultured neurons increases the activity of glycogen synthase kinase 3 (GSK-3), which is accompanied by the enhanced phosphorylation of some microtubule-associated proteins including tau and microtubule-associated protein 2. Prion peptide-treated neurons become progressively atrophic, and die ultimately. Both lithium and insulin, which inhibit GSK-3 activity, significantly decrease prion peptide-induced cell death both in primary neuronal cultures and in neuroblastoma cells. Finally, the overexpression of a dominant-negative mutant of GSK-3 in transfected neuroblastoma cells efficiently prevents prion peptide-induced cell death. These results are consistent with the view that the activation of GSK-3 is a crucial mediator of prion peptide-induced neurodegeneration.

scholarly journals Implication of glycogen synthase kinase 3 in diabetes-associated islet inflammation

2020 ◽  
Vol 244 (1) ◽  
pp. 133-148 ◽  
Author(s):  
Caterina Luana Pitasi ◽  
Junjun Liu ◽  
Blandine Gausserès ◽  
Gaëlle Pommier ◽  
Etienne Delangre ◽  
...  
Keyword(s):  
Inflammatory Response ◽  
Inflammatory Cytokines ◽  
Glycogen Synthase ◽  
Glycogen Synthase Kinase ◽  
Glycogen Synthase Kinase 3 ◽  
Diabetic Rat ◽  
Gk Rats ◽  
Islet Inflammation ◽  
The Impact ◽  
Pro Inflammatory Cytokines

Islet inflammation is associated with defective β cell function and mass in type 2 diabetes (T2D). Glycogen synthase kinase 3 (GSK3) has been identified as an important regulator of inflammation in different diseased conditions. However, the role of GSK3 in islet inflammation in the context of diabetes remains unexplored. In this study, we investigated the direct implication of GSK3 in islet inflammation in vitro and tested the impact of GSK3 inhibition in vivo, on the reduction of islet inflammation, and the improvement of glucose metabolism in the Goto-Kakizaki (GK) rat, a spontaneous model of T2D. GK rats were chronically treated with infra-therapeutic doses of lithium, a widely used inhibitor of GSK3. We analyzed parameters of glucose homeostasis as well as islet inflammation and fibrosis in the endocrine pancreas. Ex vivo, we tested the impact of GSK3 inhibition on the autonomous inflammatory response of non-diabetic rat and human islets, exposed to a mix of pro-inflammatory cytokines to mimic an inflammatory environment. Treatment of young GK rats with lithium prevented the development of overt diabetes. Lithium treatment resulted in reduced expression of pro-inflammatory cytokines in the islets. It decreased islet fibrosis and partially restored the glucose-induced insulin secretion in GK rats. Studies in non-diabetic human and rat islets exposed to inflammatory environment revealed the direct implication of GSK3 in the islet autonomous inflammatory response. We show for the first time, the implication of GSK3 in islet inflammation and suggest this enzyme as a viable target to treat diabetes-associated inflammation.

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