Hydrogen sulfide protects neurons against hypoxic injury via stimulation of ATP-sensitive potassium channel/protein kinase C/extracellular signal-regulated kinase/heat shock protein90 pathway

Neuroscience ◽  
2010 ◽  
Vol 167 (2) ◽  
pp. 277-286 ◽  
Author(s):  
A.S. Tay ◽  
L.F. Hu ◽  
M. Lu ◽  
P.T.H. Wong ◽  
J.S. Bian
1998 ◽  
Vol 18 (2) ◽  
pp. 790-798 ◽  
Author(s):  
Dorothee C. Schönwasser ◽  
Richard M. Marais ◽  
Christopher J. Marshall ◽  
Peter J. Parker

ABSTRACT Phorbol ester treatment of quiescent Swiss 3T3 cells leads to cell proliferation, a response thought to be mediated by protein kinase C (PKC), the major cellular receptor for this class of agents. We demonstrate here that this proliferation is dependent on the activation of the extracellular signal-regulated kinase/mitogen-activated protein kinase (ERK/MAPK) cascade. It is shown that dominant-negative PKC-α inhibits stimulation of the ERK/MAPK pathway by phorbol esters in Cos-7 cells, demonstrating a role for PKC in this activation. To assess the potential specificity of PKC isotypes mediating this process, constitutively active mutants of six PKC isotypes (α, β1, δ, ɛ, η, and ζ) were employed. Transient transfection of these PKC mutants into Cos-7 cells showed that members of all three groups of PKC (conventional, novel, and atypical) are able to activate p42 MAPK as well as its immediate upstream activator, the MAPK/ERK kinase MEK-1. At the level of Raf, the kinase that phosphorylates MEK-1, the activation cascade diverges; while conventional and novel PKCs (isotypes α and η) are potent activators of c-Raf1, atypical PKC-ζ cannot increase c-Raf1 activity, stimulating MEK by an independent mechanism. Stimulation of c-Raf1 by PKC-α and PKC-η was abrogated for RafCAAX, which is a membrane-localized, partially active form of c-Raf1. We further established that activation of Raf is independent of phosphorylation at serine residues 259 and 499. In addition to activation, we describe a novel Raf desensitization induced by PKC-α, which acts to prevent further Raf stimulation by growth factors. The results thus demonstrate a necessary role for PKC and p42 MAPK activation in 12-O-tetradecanoylphorbol-13-acetate induced mitogenesis and provide evidence for multiple PKC controls acting on this MAPK cascade.


2012 ◽  
Vol 117 (2) ◽  
pp. 293-301 ◽  
Author(s):  
Björn Müller-Edenborn ◽  
Birgit Roth-Z'graggen ◽  
Kamila Bartnicka ◽  
Alain Borgeat ◽  
Alexandra Hoos ◽  
...  

Background Invasion of extracellular matrix is a hallmark of malignant tumors. Clamping maneuvers during cancer surgery reduce blood loss, but trigger reperfusion injury (RI). RI increases cancer recurrence in the reperfused organ through up-regulation of matrix metalloproteinase-9 (MMP-9). Interleukin-8 is an important cytokine in RI promoting accumulation of neutrophils, a major source of MMP-9. Volatile anesthetics were demonstrated to reduce RI. We hypothesized that these anesthetics might attenuate MMP-9 up-regulation and consequently tumor cell invasion in RI. Methods Isolated human neutrophils (n = 6) were preconditioned with sevoflurane or desflurane, followed by stimulation with interleukin-8, phorbol myristate acetate, or chemokine CXC-ligand 1 (CXCL1) to differentiate intracellular pathways. MMP-9 release and activity were quantified by enzyme-linked immunosorbent assay and zymography, respectively. CXC-receptor-2 (CXCR2) expression and phosphorylation of extracellular signal-regulated kinases 1/2 were assessed by flow cytometry. The impact of MMP-9 on the invasion of neutrophils and MC-38 colon cancer cells was assessed using Matrigel-coated filters (n = 6). Results Preconditioning reduced interleukin-8-induced MMP-9-release by 41% (±13, 5%, sevoflurane) and 40% (±13%, desflurane). This was also evident following stimulation of CXCR2 with CXCL1. No impact on phosphorylation of extracellular signal-regulated kinases 1/2 and MMP-9 release was observed with receptor-independent stimulation of protein kinase C with phorbol myristate acetate. Preconditioning reduced transmigration of neutrophils and MC-38 tumor cells to baseline levels. Discussion Volatile anesthetics impair neutrophil MMP-9 release and interfere with pathways downstream of CXCR2, but upstream of protein kinase C. Through down-regulation of MMP-9, volatile anesthetics decrease Matrigel breakdown and reduce subsequent migration of cancer cells in vitro.


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