Inhibition of stress-activated protein kinase in the ischemic/reperfused heart: role of magnesium tanshinoate B in preventing apoptosis11Abbreviations: JIP, JNK-interacting protein; MAP, mitogen-activated protein; p38 MAPK, p38 MAP kinase; MTB, magnesium tanshinoate B; PARP, poly(ADP-ribose) polymerase; PMSF, phenylmethylsulfonyl fluoride; SAP, stress-activated protein; and TUNEL, terminal deoxyribonucleotide transferase (TdT)-mediated dUTP nick-end labeling.

2001 ◽  
Vol 62 (4) ◽  
pp. 483-493 ◽  
Author(s):  
Kathy K.W. Au-Yeung ◽  
Da-yuan Zhu ◽  
Karmin O ◽  
Yaw L. Siow
1999 ◽  
Vol 19 (1) ◽  
pp. 21-30 ◽  
Author(s):  
Ming Zhao ◽  
Liguo New ◽  
Vladimir V. Kravchenko ◽  
Yutaka Kato ◽  
Hermann Gram ◽  
...  

ABSTRACT Members of the MEF2 family of transcription factors bind as homo- and heterodimers to the MEF2 site found in the promoter regions of numerous muscle-specific, growth- or stress-induced genes. We showed previously that the transactivation activity of MEF2C is stimulated by p38 mitogen-activated protein (MAP) kinase. In this study, we examined the potential role of the p38 MAP kinase pathway in regulating the other MEF2 family members. We found that MEF2A, but not MEF2B or MEF2D, is a substrate for p38. Among the four p38 group members, p38 is the most potent kinase for MEF2A. Threonines 312 and 319 within the transcription activation domain of MEF2A are the regulatory sites phosphorylated by p38. Phosphorylation of MEF2A in a MEF2A-MEF2D heterodimer enhances MEF2-dependent gene expression. These results demonstrate that the MAP kinase signaling pathway can discriminate between different MEF2 isoforms and can regulate MEF2-dependent genes through posttranslational activation of preexisting MEF2 protein.


2002 ◽  
Vol 283 (4) ◽  
pp. L859-L866 ◽  
Author(s):  
M. R. Karamsetty ◽  
J. R. Klinger ◽  
N. S. Hill

Mitogen-activated protein (MAP) kinases regulate smooth muscle cell contraction. Hypoxia contracts pulmonary arteries by mechanisms that are incompletely understood. We hypothesized that hypoxic contraction of pulmonary arteries involves activation of the MAP kinases. To test this hypothesis, we studied the effects of SB-202190, a p38 MAP kinase inhibitor, PD-98059 and UO-126, two structurally different MEKK inhibitors, and anisomycin, a stimulator of p38 MAP kinase on acute hypoxia-induced contraction in rat conduit pulmonary artery rings precontracted with phenylephrine or KCl. Hypoxia induced a transient contraction, followed by a relaxation, and then a slowly developing sustained contraction. Hypoxia also significantly increased phosphorylation of p38 MAP kinase. SB-202190 did not affect the transient phase but abrogated the sustained phase of hypoxic contraction, whereas anisomycin enhanced both phases of contraction. SB-202190 also attenuated and anisomycin enhanced the phenylephrine-induced contraction. In contrast, PD-98059 and UO-126 had minimal effects on either hypoxic or phenylephrine-induced contraction. None of the treatments modified KCl-induced contraction. We conclude that p38, but not the ERK1/ERK2 MAP kinase pathway, mediates the sustained phase of hypoxic contraction in isolated rat pulmonary arteries.


1996 ◽  
Vol 271 (14) ◽  
pp. 8488-8492 ◽  
Author(s):  
Megan M. McLaughlin ◽  
Sanjay Kumar ◽  
Peter C. McDonnell ◽  
Stephanie Van Horn ◽  
John C. Lee ◽  
...  

2022 ◽  
Vol 54 (01) ◽  
pp. 42-49
Author(s):  
Tomoyuki Hioki ◽  
Gen Kuroyanagi ◽  
Kazuhiko Fujita ◽  
Go Sakai ◽  
Tetsu Kawabata ◽  
...  

AbstractIncretins including glucose-dependent insulinotropic polypeptide (GIP) and glucagon-like peptide-1 (GLP-1), which are secreted from the small intestine after oral food ingestion, are currently well-known to stimulate insulin secretion from pancreatic β-cells and used for the treatment of type 2 diabetes mellitus. We have previously reported that prostaglandin F2α (PGF2α) stimulates the synthesis of interleukin-6 (IL-6) and osteoprotegerin in osteoblast-like MC3T3-E1 cells, and that IL-6 and osteoprotegerin release are mediated through the p44/p42 mitogen-activated protein (MAP) kinase, p38 MAP kinase or stress-activated protein kinase/c-Jun N-terminal kinase (SAPK/JNK) pathways. In the present study, we investigated the effects of incretins including GLP-1 and GIP, on the PGF2α-induced synthesis of IL-6 and osteoprotegerin and examined the detailed mechanism in osteoblast-like MC3T3-E1 cells. We found that GIP and GLP-1 significantly stimulated the PGF2α-induced synthesis of IL-6 in osteoblast-like MC3T3-E1 cells. In addition, GIP and GLP-1 significantly enhanced the PGF2α-induced mRNA expression levels of IL-6. On the other hand, GIP and GLP-1 markedly stimulated the PGF2α-induced synthesis of osteoprotegerin. However, the phosphorylation of p44/p42 MAP kinase, p38 MAP kinase, or JNK induced by PGF2α was not affected by GIP or GLP-1. Therefore, these results strongly suggest that incretins enhance the PGF2α-induced synthesis of IL-6 and osteoprotegerin in osteoblast-like MC3T3-E1 cells. However, these syntheses are not mediated through p44/p42 MAP kinase, p38 MAP kinase, or JNK pathways.


Blood ◽  
2004 ◽  
Vol 104 (11) ◽  
pp. 470-470
Author(s):  
Mani Mohindru ◽  
Perry Pahanish ◽  
Efstratios Katsoulidis ◽  
Robert Collins ◽  
Thomas Rogers ◽  
...  

Abstract Cytokines such as TNF α, IFN γ and others have been implicated in the pathogenesis of ineffective hematopoiesis in MDS and are thought to lead to the high rate of apoptosis in hematopoietic progenitors. The p38 Mitogen Activated Protein Kinase (MAPK) is an evolutionary conserved enzyme that is involved in many cellular processes including stress signaling. We have previously shown that the p38 MAP kinase is strongly activated by IFNs, TNF α, TGF β and other inhibitory cytokines in normal primary hematopoietic progenitors and plays an important role in the negative regulation of normal hematopoiesis. In the present study, we determined the role of the p38 MAPK in the pathogenesis of MDS evaluated its inhibition as a potential therapeutic strategy in this disease. p38 MAPK inhibition was achieved by the use of a novel p38 inhibitor - SD-282, a specific inhibitor of p38α MAP kinase. SD-282 performs very similarly in animal and cell models to a p38 inhibitor now in the clinic. We also transfected primary hematopoietic cells with flurescent labeled siRNAs against p38 and successfully downregulated the levels of the protein. Using these approaches, we demonstrate that pharmacological inhibition of the p38 MAPK can reverse the growth inhibitory effects of TNF α and IFN γ on erythroid and myeloid colony formation. This reversal of TNF α mediated inhibition correlates with significant reduction of apoptosis seen in human hematopoeitic progenitors pretreated with p38 inhibitor SD-282. Having established the importance of p38 MAPK in cytokine mediated inhibition of normal hematopoiesis, we performed colony forming assays with bone marrow CD34+ cells from 8 patients with MDS in the presence of either pharmacologic or siRNA based inhibitors of p38. All patients had refractory cytopenias with multilineage dysplasia. Our data indicates that SD-282 treatment strongly enhances both erythroid and myeloid colony formation in MDS CD34+ bone marrow cells in vitro. This increase was not observed when these progenitors were grown in the presence of negative controls - SB 202474 and the MEK inhibitor PD 98059. Similarly, an increase in hematopoietic colony formation, though of a lesser magnitude was seen when MDS bone marrow progenitors were transfected with siRNAs against p38 MAPK. To further determine the role of cytokines in the pathogenesis of MDS, we also used bone marrow derived sera from the same MDS patients. Our studies show exposure to patient derived sera led to the phosphorylation/activation of p38 MAPK in normal hematopoietic progenitors when compared to sera from healthy volunteers. Our studies also demonstrate that bone marrow derived sera from MDS patients can inhibit erythroid and myeloid colony formation of normal hematopoietic progenitors. This inhibition can be reversed by blocking p38 MAPK using SD-282, other p38 inhibitors and siRNAs. This finding confirms the role of marrow cytokine /serum factors in the ineffective hematopoiesis seen in MDS and suggests the importance of p38 MAPK activation in this phenomenon. Thus our studies show the p38 MAPK may be a common effector of inhibitory cytokine signaling in normal and MDS hematopoietic cells. These results provide a strong rationale for using p38 inhibition as a novel treatment strategy for MDS. Supported by Harris Methodist Foundation Grant, VISN-17 New Investigator Grant and VA Research Corp Grant to AV.


2005 ◽  
Vol 25 (9) ◽  
pp. 3670-3681 ◽  
Author(s):  
Deborah Brancho ◽  
Juan-Jose Ventura ◽  
Anja Jaeschke ◽  
Beth Doran ◽  
Richard A. Flavell ◽  
...  

ABSTRACT Mixed-lineage protein kinase 3 (MLK3) is a member of the mitogen-activated protein (MAP) kinase kinase kinase group that has been implicated in multiple signaling cascades, including the NF-κB pathway and the extracellular signal-regulated kinase, c-Jun NH2-terminal kinase (JNK), and p38 MAP kinase pathways. Here, we examined the effect of targeted disruption of the murine Mlk3 gene. Mlk3 −/− mice were found to be viable and healthy. Primary embryonic fibroblasts prepared from these mice exhibited no major signaling defects. However, we did find that MLK3 deficiency caused a selective reduction in tumor necrosis factor (TNF)-stimulated JNK activation. Together, these data demonstrate that MLK3 contributes to the TNF signaling pathway that activates JNK.


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