Leishmania mexicana lipophosphoglycan activates ERK and p38 MAP kinase and induces production of proinflammatory cytokines in human macrophages through TLR2 and TLR4

SUMMARYProtozoan parasites of genus Leishmania are the causative agents of leishmaniasis. Leishmania promastigotes primarily infect macrophages in the host, where they transform into amastigotes and multiply. Lipophosphoglycan (LPG), the most abundant surface molecule of the parasite, is a virulence determinant that regulates the host immune response. Promastigotes are able to modulate this effect through LPG, creating a favourable environment for parasite survival, although the mechanisms underlying this modulation remain unknown. We analysed the participation of TLR2 and TLR4 in the production of cytokines and explored the possible phosphorylation of ERK and/or p38 MAP kinase signalling cascades in human macrophages stimulated with Leishmania mexicana LPG. The results show that LPG induced the production of TNF-α, IL-1β, IL-12p40, IL-12p70 and IL-10 and led to phosphorylation of ERK and p38 MAP kinase. Specific inhibitors of ERK or p38 MAP kinases and mAbs against TLR2 and TLR4 reduced cytokine production and phosphorylation of both kinases. Our results suggest that L. mexicana LPG binds TLR2 and TLR4 receptors in human macrophages, leading to ERK and MAP kinase phosphorylation and production of pro-inflammatory cytokines.

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Functional Role of p38 Mitogen Activated Protein Kinase in Platelet Activation induced by a Thromboxane A2 Analogue and by 8-iso-prostaglandin F2 α

Thrombosis and Haemostasis ◽

10.1055/s-0037-1613101 ◽

2002 ◽

Vol 87 (05) ◽

pp. 888-898 ◽

Cited By ~ 23

Author(s):

Stefania Gaino ◽

Valeria Zuliani ◽

Rosa Tommasoli ◽

Donatella Benati ◽

Riccardo Ortolani ◽

...

Keyword(s):

Map Kinase ◽

Platelet Activation ◽

Tyrosine Kinases ◽

Actin Polymerization ◽

Shape Change ◽

Specific Inhibitor ◽

P38 Map Kinase ◽

Mitogen Activated Protein Kinase ◽

Mitogen Activated Protein ◽

Kinase Phosphorylation

SummaryWe investigated similarities in the signaling pathways elicited by the F2 isoprostane 8-iso-PGF2α and by low doses of U46619 to induce platelet activation. Both 0.01-0.1 µmol/L U46619 and 0.01-1 µmol/L 8-isoPGF2α triggered shape change and filopodia extension, as well as adhesion to immobilized fibrinogen of washed platelets. At these doses the two platelet agonists failed to trigger secretion and aggregation, which were however induced by higher doses of U46619 (0.1-1 µmol/L). SB203580 (1-10 µmol/L), a specific inhibitor of the p38 mitogen activated protein (MAP) kinase blunted platelet shape change and adhesion induced by 0.05-1 µmol/L 8-iso-PGF2α and by 0.01 µmol/L U46619. These platelet responses were also inhibited by 20 µmol/L cytochalasin D, an inhibitor of actin polymerization, and 50 µmol/L piceatannol, an inhibitor of the Syk tyrosine kinases. Both 8-iso-PGF2α and U46619-induced p38 MAP kinase phosphorylation in suspended platelets and this was inhibited by piceatannol, indicating that Syk activation occurs upstream p38 MAP kinase phosphorylation. These findings suggest that the signaling pathway triggered by both 8-iso-PGF2α and low concentrations of U46619 to induce platelet adhesion and shape change implicates Syk, the p38 MAP kinase, and actin polymerization.

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Coupling of M2 muscarinic receptors to ERK MAP kinases and caldesmon phosphorylation in colonic smooth muscle

AJP Gastrointestinal and Liver Physiology ◽

10.1152/ajpgi.2000.278.3.g429 ◽

2000 ◽

Vol 278 (3) ◽

pp. G429-G437 ◽

Cited By ~ 21

Author(s):

Amy K. Cook ◽

Michael Carty ◽

Cherie A. Singer ◽

Ilia A. Yamboliev ◽

William T. Gerthoffer

Keyword(s):

Smooth Muscle ◽

Map Kinase ◽

Muscarinic Receptors ◽

Map Kinases ◽

Kinase Inhibitor ◽

Receptor Activation ◽

Inhibitory Effect ◽

Subsequent Treatment ◽

P38 Map Kinase

Coupling of M2 and M3 muscarinic receptors to activation of mitogen-activated protein (MAP) kinases and phosphorylation of caldesmon was studied in canine colonic smooth muscle strips in which M3 receptors were selectively inactivated by N, N-dimethyl-4-piperidinyl diphenylacetate (4-DAMP) mustard (40 nM). ACh elicited activation of extracellular signal-regulated kinase (ERK) 1, ERK2, and p38 MAP kinases in control muscles and increased phosphorylation of caldesmon (Ser789), a putative downstream target of MAP kinases. Alkylation of M3 receptors with 4-DAMP had only a modest inhibitory effect on ERK activation, p38 MAP kinase activation, and caldesmon phosphorylation. Subsequent treatment with 1 μM AF-DX 116 completely prevented activation of ERK and p38 MAP kinase and prevented caldesmon phosphorylation. Caldesmon phosphorylation was blocked by the MAP kinase/ERK kinase inhibitor PD-98509 but not by the p38 MAP kinase inhibitor SB-203580. These results indicate that colonic smooth muscle M2 receptors are coupled to ERK and p38 MAP kinases. Activation of ERK, but not p38 MAP kinases, results in phosphorylation of caldesmon in vivo, which is a novel function for M2receptor activation in smooth muscle.

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205 INVOLVEMENT OF P38 MAP KINASE PHOSPHORYLATION IN CHONDROCYTE APOPTOSIS INDUCED BY MECHANICAL STRESS AND HEAT STRESS

Osteoarthritis and Cartilage ◽

10.1016/s1063-4584(09)60227-2 ◽

2009 ◽

Vol 17 ◽

pp. S117

Author(s):

K. Takebe ◽

T. Nishiyama ◽

S. Hashimoto ◽

T. Fujishiro ◽

N. Kanzaki ◽

...

Keyword(s):

Heat Stress ◽

Map Kinase ◽

Mechanical Stress ◽

P38 Map Kinase ◽

Chondrocyte Apoptosis ◽

Kinase Phosphorylation

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Separating myoblast differentiation from muscle cell fusion using IGF-I and the p38 MAP kinase inhibitor SB202190

AJP Cell Physiology ◽

10.1152/ajpcell.00184.2015 ◽

2015 ◽

Vol 309 (7) ◽

pp. C491-C500 ◽

Cited By ~ 9

Author(s):

Samantha Gardner ◽

Sean M. Gross ◽

Larry L. David ◽

John E. Klimek ◽

Peter Rotwein

Keyword(s):

Growth Factor ◽

Map Kinase ◽

Cell Fusion ◽

Muscle Cell ◽

Map Kinases ◽

Kinase Inhibitor ◽

P38 Map Kinase ◽

Myoblast Differentiation ◽

Igf I ◽

Muscle Biology

The p38 MAP kinases play critical roles in skeletal muscle biology, but the specific processes regulated by these kinases remain poorly defined. Here we find that activity of p38α/β is important not only in early phases of myoblast differentiation, but also in later stages of myocyte fusion and myofibrillogenesis. By treatment of C2 myoblasts with the promyogenic growth factor insulin-like growth factor (IGF)-I, the early block in differentiation imposed by the p38 chemical inhibitor SB202190 could be overcome. Yet, under these conditions, IGF-I could not prevent the later impairment of muscle cell fusion, as marked by the nearly complete absence of multinucleated myofibers. Removal of SB202190 from the medium of differentiating myoblasts reversed the fusion block, as multinucleated myofibers were detected several hours later and reached ∼90% of the culture within 30 h. Analysis by quantitative mass spectroscopy of proteins that changed in abundance following removal of the inhibitor revealed a cohort of upregulated muscle-enriched molecules that may be important for both myofibrillogenesis and fusion. We have thus developed a model system that allows separation of myoblast differentiation from muscle cell fusion and should be useful in identifying specific steps regulated by p38 MAP kinase-mediated signaling in myogenesis.

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Activation of p38 MAP Kinase and JNK But Not ERK Is Required for Erythropoietin-Induced Erythroid Differentiation

Blood ◽

10.1182/blood.v92.6.1859.418k37_1859_1869 ◽

1998 ◽

Vol 92 (6) ◽

pp. 1859-1869 ◽

Cited By ~ 7

Author(s):

Yuka Nagata ◽

Noriko Takahashi ◽

Roger J. Davis ◽

Kazuo Todokoro

Keyword(s):

Cell Growth ◽

Map Kinase ◽

Antisense Oligonucleotides ◽

Map Kinases ◽

Physiological Function ◽

Critical Role ◽

Specific Inhibitor ◽

Erythroid Differentiation ◽

P38 Map Kinase ◽

American Society

p38 MAP kinase (p38) and JNK have been described as playing a critical role in the response to a variety of environmental stresses and proinflammatory cytokines. It was recently reported that hematopoietic cytokines activate not only classical MAP kinases (ERK), but also p38 and JNK. However, the physiological function of these kinases in hematopoiesis remains obscure. We found that all MAP kinases examined, ERK1, ERK2, p38, JNK1, and JNK2, were rapidly and transiently activated by erythropoietin (Epo) stimulation in SKT6 cells, which can be induced to differentiate into hemoglobinized cells in response to Epo. Furthermore, p38-specific inhibitor SB203580 but not MEK-specific inhibitor PD98059 significantly suppressed Epo-induced differentiation and antisense oligonucleotides of p38, JNK1, and JNK2, but neither ERK1 nor ERK2 clearly inhibited Epo-induced hemoglobinization. However, in Epo-dependent FD-EPO cells, inhibition of either ERKs, p38, or JNKs suppressed cell growth. Furthermore, forced expression of a gain-of-function MKK6 mutant, which specifically activated p38, induced hemoglobinization of SKT6 cells without Epo. These results indicate that activation of p38 and JNKs but not of ERKs is required for Epo-induced erythroid differentiation of SKT6 cells, whereas all of these kinases are involved in Epo-induced mitogenesis of FD-EPO cells. © 1998 by The American Society of Hematology.

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Spontaneous activation of the NF-κB signaling pathway in isolated normal glomeruli

AJP Renal Physiology ◽

10.1152/ajprenal.00513.2005 ◽

2006 ◽

Vol 291 (6) ◽

pp. F1169-F1176 ◽

Cited By ~ 11

Author(s):

Kunihiro Hayakawa ◽

Yiman Meng ◽

Nobuhiko Hiramatsu ◽

Ayumi Kasai ◽

Jian Yao ◽

...

Keyword(s):

Map Kinase ◽

Map Kinases ◽

Mesangial Cells ◽

Ex Vivo ◽

P38 Map Kinase ◽

Paracrine Factors ◽

Enhancer Element ◽

Monocyte Chemoattractant Protein 1 ◽

Isolated Glomeruli ◽

Tnf Α

In this report, we describe that NF-κB is spontaneously activated in isolated, normal glomeruli. Ex vivo incubation of isolated rat glomeruli triggered expression of a NF-κB-dependent gene, monocyte chemoattractant protein-1 (MCP-1), in parallel with downregulation of IκBα and IκBβ proteins and activation of the p65 NF-κB subunit. The induction of MCP-1 was also observed in mesangial cells coincubated with isolated glomeruli or exposed to media conditioned by isolated glomeruli (GCM), which was abrogated by inhibition of NF-κB. The activation of NF-κB by glomerulus-derived factors was confirmed using reporter mesangial cells that produce secreted alkaline phosphatase (SEAP) under the control of the κB enhancer element. When the reporter cells were adoptively transferred into normal glomeruli, expression of SEAP mRNA and activity of SEAP were also upregulated in the explanted glomeruli. The molecular weight of factors responsible for activation of NF-κB was >50 kDa, and TNF-α was identified as one of glomerulus-derived activators. To examine upstream events involved, we focused on MAP kinases that are spontaneously activated in explanted glomeruli. Selective suppression of ERK or p38 MAP kinase significantly attenuated activation of NF-κB in mesangial cells triggered by coculture with isolated glomeruli. Interestingly, the suppressive effects by MAP kinase inhibitors were not observed in mesangial cells treated with GCM. These data suggested that NF-κB was spontaneously activated in explanted glomeruli via autocrine/paracrine factors including TNF-α and that the production of NF-κB activators by glomeruli was, at least in part, through MAP kinase pathways.

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PTHrP stimulated by the calcium-sensing receptor requires MAP kinase activation

AJP Endocrinology and Metabolism ◽

10.1152/ajpendo.00143.2002 ◽

2003 ◽

Vol 284 (2) ◽

pp. E435-E442 ◽

Cited By ~ 49

Author(s):

R. John MacLeod ◽

Naibedya Chattopadhyay ◽

Edward M. Brown

Keyword(s):

Map Kinase ◽

Map Kinases ◽

Kinase Inhibitor ◽

Hormone Secretion ◽

P38 Map Kinase ◽

Mitogen Activated Protein Kinase ◽

Humoral Hypercalcemia Of Malignancy ◽

Calcium Sensing Receptor ◽

Calcium Sensing ◽

Hek Cells

Increases in extracellular calcium concentration ([Ca2+]o) stimulate from normal and malignant cells secretion of parathroid hormone-related protein (PTHrP), a major mediator of humoral hypercalcemia of malignancy. Because the calcium-sensing receptor (CaR) is a determinant of calcium-regulated hormone secretion, we examined whether HEK cells stably transfected with human CaR secreted PTHrP in response to CaR stimulation. Increases in [Ca2+]o or neomycin and Gd3+ all substantially increased PTHrP secretion in CaR-HEK cells but had no effect on nontransfected cells. CaR activation likewise increased PTHrP transcripts. PD-098059 and U-0126, inhibitors of the mitogen-activated protein kinase kinase MEK1/2, abolished CaR-stimulated secretion but had no effect on basal secretion. An inhibitor of p38 MAP kinase, SB-203580, also attenuated CaR-stimulated secretion. Western analysis revealed that CaR activation caused a robust increase in MEK1/2 and p38 MAP kinase phosphorylation. A Src family kinase inhibitor, PP2, blocked both basal and CaR-stimulated secretion. We conclude that CaR specifically mediates the effect of increasing [Ca2+]o on PTHrP synthesis and secretion and that activated MEK1/2 and p38 MAP kinases are determinants of the CaR's stimulation of PTHrP secretion.

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Involvement of endogenous nitric oxide in angiotensin II-induced activation of vascular mitogen-activated protein kinases

AJP Heart and Circulatory Physiology ◽

10.1152/ajpheart.00288.2007 ◽

2007 ◽

Vol 293 (4) ◽

pp. H2403-H2408 ◽

Cited By ~ 10

Author(s):

Guo-Xing Zhang ◽

Yukiko Nagai ◽

Toshitaka Nakagawa ◽

Hiroshi Miyanaka ◽

Yoshihide Fujisawa ◽

...

Keyword(s):

Nitric Oxide ◽

Angiotensin Ii ◽

Map Kinase ◽

Map Kinases ◽

No Synthase ◽

Dependent Manner ◽

Ang Ii ◽

No Donor ◽

Mitogen Activated Protein ◽

Kinase Phosphorylation

Angiotensin II (ANG II) is a powerful activator of mitogen-activated protein (MAP) kinase cascades in cardiovascular tissues through a redox-sensitive mechanism. Nitric oxide (NO) is considered to antagonize the vasoconstrictive and proarteriosclerotic actions of ANG II. However, the role of endogenous NO in ANG II-induced redox-sensitive signal transduction is not yet clear. In this study using catheterized, conscious rats, we found that acute intravenous administration of NG-nitro-l-arginine methyl ester (l-NAME; 5 mg/kg) enhanced phosphorylation of aortic MAP kinases extracellular signal regulated kinase (ERK) 1/2 and p38, which were suppressed only partially by a superoxide dismutase mimetic (Tempol), whereas ANG II-induced MAP kinase phosphorylation was markedly suppressed by Tempol. FK409, a NO donor, had little effect on vascular MAP kinase phosphorylation. On the other hand, acute exposure to a vasoconstrictor dose of ANG II (200 ng·kg−1·min−1 iv) failed to enhance phosphorylation of aortic MAP kinases in the chronically l-NAME-treated rats, whereas the vasoconstrictor effect of ANG II was not affected by l-NAME treatment. Furthermore, three different inhibitors of NO synthase suppressed, in a dose-dependent manner, ANG II-induced MAP kinase phosphorylation in rat vascular smooth muscle cells, which was closely linked to superoxide generation in cells. These results indicate the involvement of endogenous NO synthase in ANG II-induced signaling pathways, leading to activation of MAP kinase, and that NO may have dual effects on the vascular MAP kinase activation associated with redox sensitivity.

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