Search results for "Mitogen-Activated Protein Kinase"

Investigational agents for Crohn's disease.

2010

IMPORTANCE OF THE FIELD: Increased understanding of the biological mechanisms of Crohn's disease has opened the door to a large number of new molecules; some of these are approved for clinical use, while others remain under evaluation. In this review, we examine the clinical efficacy of all the new drugs that have been evaluated in controlled trials in the last 12 years. AREAS COVERED IN THIS REVIEW: Anti-TNF therapy has been reviewed briefly, given the many comprehensive reviews on this topic; attention is focused mainly on the other biological therapies. In assessing the clinical efficacy of these molecules, we consider only the remission rate, as this is considered the most meaningful en…

POLYPHENOLS FROM RED WINE MODULATE IMMUNE RESPONSIVENESS: BIOLOGICAL AND CLINICAL SIGNIFICANCE.

2008

Many studies have been conducted on the effects of red wine polyphenols on certain diseases, primarily, coronary heart disease (CHD) and, in this respect, evidence has been demonstrated that intake of red wine is associated with a reduction of CHD symptomatology. In this framework, the purpose of this review is to illustrate the effects of polyphenols on immune cells from human healthy peripheral blood. Data will show that polyphenols are able to stimulate both innate and adaptive immune responses. In particular, the release of cytokines such as interleukin (IL)-12, interferon (IFN)-gamma, and IL-10 as well as immunoglobulins may be important for host protection in different immune related …

Myeloperoxidase mediates neutrophil activation by association with CD11b/CD18 integrins.

2004

Recruitment and activation of polymorphonuclear neutrophils (PMNs) reflects a primary immunological response to invading pathogens and has also emerged as a hallmark of vascular inflammation. One of the principal enzymes released upon PMN activation is myeloperoxidase (MPO), a heme protein that not only generates cytotoxic oxidants but also impacts deleteriously on nitric oxide-dependent signaling cascades within the vasculature. Because MPO also associates with the membrane of PMN, we evaluated whether MPO could also function as an autocrine modulator of PMN activation. The extent of PMN membrane-associated MPO was elevated in patients with acute inflammatory vascular disease compared with…

Activation of the p38MAPK cascade is associated with upregulation of TNF alpha receptors in the spinal motor neurons of mouse models of familial ALS.

2005

Phosphorylated p38 mitogen-activated protein kinase (p38MAPK), but not activated c-jun-N-terminal kinase (JNK), increases in the motor neurons of transgenic mice overexpressing ALS-linked SOD1 mutants at different stages of the disease. This effect is associated with a selective increase of phosphorylated MKK3-6, MKK4 and ASK1 and a concomitant upregulation of the TNFalpha receptors (TNFR1 and TNFR2), but not IL1beta and Fas receptors. Activation of both p38 MAPK and JNK occurs in the activated microglial cells of SOD1 mutant mice at the advanced stage of the disease; however, this effect is not accompanied by the concomitant activation of the upstream kinases ASK1 and MKK3,4,6, while both …

Protein Phosphorylation by Peroxisome Proliferators: Species-specific Stimulation of Protein Kinases and Its Role in PP-induced Transcriptional Activ…

1996

Activation of NF-kappaB and IL-8 by yersinia enterocolitica invasin protein is conferred by engagement of rac1 and MAP kinase cascades.

2003

International audience; Yersinia enterocolitica triggers activation of the nuclear factor (NF)-kappaB and production of the proinflammatory chemokine interleukin (IL)-8 in intestinal epithelial cells. This activation is due to adhesion of the bacteria via their outer membrane protein invasin to the host cells. Using Clostridium difficile toxins that specifically inactivate small GTPases, and transfection of inhibitory proteins of the Rho-GTPases, we demonstrate that Rac1, but not Cdc42 or Rho, is required for activation of NF-kappaB by invasin. Invasin activated the mitogen activated protein kinases (MAPK) p38 and c-Jun N-terminal protein kinase (JNK) but not extracellular signal regulated …

Aplidin® induces JNK-dependent apoptosis in human breast cancer cells via alteration of glutathione homeostasis, Rac1 GTPase activation, and MKP-1 ph…

2006

Aplidin® is an antitumor agent in phase II clinical trials that induces apoptosis through the sustained activation of Jun N-terminal kinase (JNK). We report that Aplidin® alters glutathione homeostasis increasing the ratio of oxidized to reduced forms (GSSG/GSH). Aplidin® generates reactive oxygen species and disrupts the mitochondrial membrane potential. Exogenous GSH inhibits these effects and also JNK activation and cell death. We found two mechanisms by which Aplidin® activates JNK: rapid activation of Rac1 small GTPase and downregulation of MKP-1 phosphatase. Rac1 activation was diminished by GSH and enhanced by L-buthionine (SR)-sulfoximine, which inhibits GSH synthesis. Downregulatio…

Rho GTPases in human breast tumours: expression and mutation analyses and correlation with clinical parameters

2002

In the present study, we addressed the question of a putative relevance of Rho proteins in tumour progression by analysing their expression on protein and mRNA level in breast tumours. We show that the level of RhoA, RhoB, Rac1 and Cdc42 protein is largely enhanced in all tumour samples analysed (n=15) as compared to normal tissues originating from the same individual. The same is true for 32P-ADP-ribosylation of Rho proteins which is catalysed by Clostridium botulinum exoenzyme C3. Also the amount of Rho-GDI and ERK2 as well as the level of overall 32P-GTP binding acvitity was tumour-specific elevated, yet to a lower extent than Rho proteins. Although the amount of Rho proteins was enhance…

Rho GTPases are over-expressed in human tumors.

1999

Small GTPases of the Rho family are involved in the regulation of a variety of cellular processes, such as the organization of the microfilamental network, cell-cell contact and malignant transformation. To address the question of whether Rho proteins are involved in carcinogenesis in man, we compared their expression in tumors from colon, breast and lung with that of the corresponding normal tissue originating from the same patient. As shown by Rho-specific 32P-ADP-ribosylation, as well as Western-blot analysis, the amount of RhoA protein was largely increased in all 3 types of tumors tested. The most dramatic differences in the expression of Rho GTPases were observed in breast tissue. All…

Late Activation of Stress-activated Protein Kinases/c-Jun N-terminal Kinases Triggered by Cisplatin-induced DNA Damage in Repair-defective Cells

2011

Although stress-activated protein kinases/c-Jun N-terminal kinases (SAPK/JNK) are rapidly activated by genotoxins, the role of DNA damage in this response is not well defined. Here we show that the SEK1/MKK4-mediated dual phosphorylation of SAPK/JNK (Thr-183/Tyr-185) correlates with the level of cisplatin-DNA adducts at late times (16–24 h) after drug treatment in both human and mouse cells. Transfection of platinated plasmid DNA also caused SAPK/JNK activation. A defect in transcription-coupled nucleotide excision repair resting on a mutation in Cockayne syndrome group B protein promoted the late SAPK/JNK activation following cisplatin exposure. Signaling to SAPK/JNK was accompanied by act…