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Mitogen-activated Protein Kinase Signaling Pathway (mitogen-activated + protein_kinase_signaling_pathway)

Distribution by Scientific Domains

Medical Sciences	75%

Selected Abstracts

Co-induction of activity-dependent genes in songbirds

EUROPEAN JOURNAL OF NEUROSCIENCE, Issue 7 2005
Tarciso A. F. Velho
Abstract Song behavior in songbirds induces the expression of activity-dependent genes in brain areas involved in perceptual processing, production and learning of song. This genomic response is thought to represent a link between neuronal activation and long-term changes in song-processing circuits of the songbird brain. Here we demonstrate that Arc, an activity-regulated gene whose product has dendritic localization and is associated with synaptic plasticity, is rapidly induced by song in the brain of zebra finches. We show that, in the context of song auditory stimulation, Arc expression is induced in several telencephalic auditory areas, most prominently the caudomedial nidopallium and mesopallium, whereas in the context of singing, Arc is also induced in song control areas, namely nucleus HVC, used as a proper name, the robust nucleus of the arcopallium and the interface nucleus of the nidopallium. We also show that song-induced Arc expression co-localizes at the cellular level with those of the transcriptional regulators zenk and c-fos, and that the song induction of these three genes is dependent on activation of the mitogen-activated protein kinase signaling pathway. These findings provide evidence for an involvement of Arc in the brain's response to birdsong. They also demonstrate that genes representing distinct genomic and cellular regulatory programs, namely early effectors and transcription factors, are co-activated in the same neuronal cells by a naturally learned stimulus. [source]

Strategy and mechanism for the prevention of hepatocellular carcinoma: Phosphorylated retinoid X receptor , is a critical target for hepatocellular carcinoma chemoprevention

CANCER SCIENCE, Issue 3 2009
Masahito Shimizu
Hepatocellular carcinoma (HCC) is a major health care problem worldwide. The prognosis of patients with HCC is poor because even in the early stages when surgical treatment might be expected to be curative, the incidence of recurrence in patients with underlying cirrhosis is very high due to multicentric carcinogenesis. Therefore, strategies to prevent recurrence and second primary HCC are required to improve the prognosis. One of the most practical approaches to prevent the multicentric development of HCC is ,clonal deletion' therapy, which is defined as the removal of latent (i.e. invisible) (pre)malignant clones from the liver in a hypercarcinogenic state. Retinoids, a group of structural and functional analogs of vitamin A, exert their biological function primarily through two distinct nuclear receptors, retinoic acid receptors and retinoid X receptors (RXR), and abnormalities in the expression and function of these receptors are highly associated with the development of various cancers, including HCC. In particular, a malfunction of RXR, due to phosphorylation by the Ras,mitogen-activated protein kinase signaling pathway is profoundly associated with the development of HCC and thus may be a critical target for HCC chemoprevention. Acyclic retinoid, which has been clinically shown to reduce the incidence of a post-therapeutic recurrence of HCC, can inhibit Ras activity and phosphorylation of the extracellular signal-regulated kinase and RXR, proteins. In conclusion, the inhibition of RXR, phosphorylation and the restoration of its physiological function as a master regulator for nuclear receptors may be a potentially effective strategy for HCC chemoprevention and clonal deletion. Acyclic retinoid, which targets phosphorylated RXR,, may thus play a critical role in preventing the development of multicentric HCC. (Cancer Sci 2009; 100: 369,374) [source]

Prevotella intermedia lipopolysaccharide stimulates release of tumor necrosis factor-, through mitogen-activated protein kinase signaling pathways in monocyte-derived macrophages

FEMS IMMUNOLOGY & MEDICAL MICROBIOLOGY, Issue 2 2007
Sung-Jo Kim
Abstract The purpose of this study was to investigate the effects of lipopolysaccharide from Prevotella intermedia, a major cause of inflammatory periodontal disease, on the production of tumor necrosis factor (TNF)-, and the expression of TNF-, mRNA in differentiated THP-1 cells, a human monocytic cell line. The potential involvement of the three main mitogen-activated protein kinase (MAPK) signaling pathways in the induction of TNF-, production was also investigated. Lipopolysaccharide from P. intermedia ATCC 25611 was prepared by the standard hot phenol,water method. THP-1 cells were incubated in the medium supplemented with phorbol myristate acetate to induce differentiation into macrophage-like cells. It was found that P. intermedia lipopolysaccharide can induce TNF-, mRNA expression and stimulate the release of TNF-, in differentiated THP-1 cells without additional stimuli. Treatment of the cells with P. intermedia lipopolysaccharide resulted in a simultaneous activation of three MAPKs [extracellular signal-related kinase 1/2 (ERK1/2), c-Jun N-terminal kinase 1/2 (JNK1/2) and p38]. Pretreatment of the cells with MAPK inhibitors effectively suppressed P. intermedia lipopolysaccharide-induced TNF-, production without affecting the expression of TNF-, mRNA. These data thus provided good evidence that the MAPK signaling pathways are required for the regulation of P. intermedia lipopolysaccharide-induced TNF-, synthesis at the level of translation more than at the transcriptional level. [source]

Cutaneous effects of infrared radiation: from clinical observations to molecular response mechanisms

PHOTODERMATOLOGY, PHOTOIMMUNOLOGY & PHOTOMEDICINE, Issue 5 2003
Stefan M. Schieke
Human skin is exposed to infrared (IR) radiation (760 nm,1 mm) from natural as well as artificial sources that are increasingly used for cosmetic or medical purposes. Epidemiological data and clinical observations, however, indicate that IR radiation cannot be considered as totally innocuous to human skin. In particular, IR radiation, similar to ultraviolet radiation, seems to be involved in photoaging and potentially also in photocarcinogenesis. The molecular consequences resulting from IR exposure are virtually unknown. Recent studies, however, have begun to shed light on the basic molecular processes such as cellular signal transduction and gene expression triggered by exposure to IR radiation. In response to IR irradiation, mitogen-activated protein kinase signaling pathways were activated mediating the upregulation of matrix metalloproteinase-1 expression. This previously unrecognized molecular ,IR response' shows that IR radiation is capable of specifically interfering with cellular functions and provides a molecular basis for biological effects of IR on human skin. [source]