## Abstract The cβJun Nβterminal kinases (JNKs) are members of the mitogenβactivated protein kinase (MAPK) family. In mammalian genomes, three genes encode the JNK family. To evaluate JNK function, mice have been created with deletions in one or more of three __Jnk__ genes. Initial studies on __jnk
c-Jun N-terminal kinases (JNKs) mediate pro-inflammatory actions of microglia
β Scribed by Vicki Waetzig; Karen Czeloth; Ute Hidding; Kirsten Mielke; Moritz Kanzow; Stephan Brecht; Mario Goetz; Ralph Lucius; Thomas Herdegen; Uwe-Karsten Hanisch
- Publisher
- John Wiley and Sons
- Year
- 2005
- Tongue
- English
- Weight
- 530 KB
- Volume
- 50
- Category
- Article
- ISSN
- 0894-1491
No coin nor oath required. For personal study only.
β¦ Synopsis
The activation and function of c-Jun N-terminal kinases (JNKs) were investigated in primary microglia cultures from neonatal rat brain, which express all three JNK isoforms. Lipopolysaccharide (LPS), tumor necrosis factor-a (TNF-a), and thrombin preparations induced a rapid and lasting activation of JNKs in the cytoplasm. In the nucleus, the activation patterns were rather complex. In untreated microglia, the small pool of nuclear JNKs was strongly activated, while the high-affinity JNK substrate c-Jun was only weakly phosphorylated. Stimulation with LPS increased the total amount of nuclear JNKs and the phosphorylation of the transcription factor c-Jun. Levels of activated JNKs in the nucleus, however, rapidly decreased. Analysis of the nuclear JNK isoforms revealed that the amount of JNK1 declined, while JNK2 increased, and the weakly expressed JNK3 did not vary. This observation suggests that JNK2 is mainly responsible for the activation of c-Jun in this context. Upstream of JNKs, LPS induced a lasting activation of the constitutively present JNK kinase MKK4. The function of JNKs in LPS-triggered cellular reactions was investigated using SP600125 (0.5-5 mM), a direct inhibitor of JNKs. Inhibition of JNKs reduced the LPS-induced metabolic activity and induction of the AP-1 target genes cyclooxygenase-2 (Cox-2), TNF-a, monocyte chemoattractant protein-1 (MCP-1), and interleukin-6 (IL-6) in response to LPS, while ERK1/2 and p38a had a more pronounced effect on LPS-induced cellular enlargement than JNKs. In summary, JNKs are essential mediators of relevant pro-inflammatory functions in microglia with different contributions of the JNK isoforms. V
π SIMILAR VOLUMES
Erosive osteolysis induced by implant-derived wear debris is mediated by recruitment and activation of osteoclasts in a pro-inflammatory microenvironment that is enriched with osteoclastogenic and pro-inflammatory cytokines such as RANKL and tumor necrosis factor alpha (TNF-alpha). These cytokines a
To examine the role of c-Jun N-terminal kinase (JNK/SAPK) in the developing nervous system of vertebrates, the localization of an active form of JNK, phosphorylated JNK (p-JNK), was studied in the lumbosacral spinal cord of the chick embryo. We also examined the localization of phosphorylated neurof
## Abstract We have previously demonstrated that activation of the Ras/Mapk pathways is required for transforming growth factor Ξ² (TGFβΞ²) induction of TGFβΞ²~1~ expression. Here we examined the role of the Ras/Mapk pathways in TGFβΞ² induction of urokinaseβtype plasminogen activator receptor (uPAR) e
## Abstract Nitric oxide (NO) can regulate osteoblast activity. In this study, we evaluated the effects of pretreatment with a low concentration of NO on osteoblast injuries induced by a high level of NO and its possible molecular mechanisms. Exposure of osteoblasts to 0.3 mM sodium nitroprusside (
## Abstract Nitric oxide (NO) can regulate chondrocyte activities. This study was aimed to evaluate the molecular mechanisms of NO donor sodium nitroprusside (SNP)βinduced insults to human chondrocytes. Exposure of human chondrocytes to SNP increased cellular NO levels but decreased cell viability