The proinflammatory cytokines tumor necrosis factor-alpha and interleukin-1 stimulate neuropeptide gene transcription and secretion in adrenochromaffin cells via activation of extracellularly regulated kinase 1/2 and p38 protein kinases, and activator protein-1 transcription factors.
Immune-autonomic interactions are known to occur at the level of the adrenal medulla, and to be important in immune and stress responses, but the molecular signaling pathways through which cytokines actually affect adrenal chromaffin cell function are unknown. Here, we studied the effects of the proinflammatory cytokines, TNF-alpha and IL-1, on gene transcription and secretion of bioactive neuropeptides, in primary bovine adrenochromaffin cells. TNF-alpha and IL-1 induced a time- and dose-dependent increase in galanin, vasoactive intestinal polypeptide, and secretogranin II mRNA levels. The two cytokines also stimulated the basal as well as depolarization-provoked release of enkephalin and secretoneurin from chromaffin cells. Stimulatory effects of TNF-alpha on neuropeptide gene expression and release appeared to be mediated through the type 2 TNF-alpha receptor, and required activation of ERK 1/2 and p38, but not Janus kinase, MAPKs. In addition, TNF-alpha increased the binding activity of activator protein-1 (AP-1) and stimulated transcription of a reporter gene containing AP-1-responsive elements in chromaffin cells. The AP-1-responsive reporter gene could also be activated through the ERK pathway. These results suggest that neuropeptide biosynthesis in chromaffin cells is regulated by TNF-alpha via an ERK-dependent activation of AP-1-responsive gene elements. Either locally produced or systemic cytokines might regulate biosynthesis and release of neuropeptides in chromaffin cells, integrating the adrenal medulla in the physiological response to inflammation. This study describes, for the first time, a signal transduction pathway activated by TNF-alpha in a major class of neuroendocrine cells that, unlike TNF-alpha signaling in lymphoid cells, employs ERK and p38 rather than Janus kinase and p38 to transmit gene-regulatory signals to the cell nucleus.
Ait-Ali
Djida
D
European Institute for Peptide Research (IFRMP 23), Institut National de la Santé et de la Recherche Médicale Unité 413, Unité Associée Centre National de la Recherche Scientifique, University of Rouen, 76821 Mont-Saint-Aignan, France.
Turquier
Valerie
V
Grumolato
Luca
L
Yon
Laurent
L
Jourdain
Matthieu
M
Alexandre
David
D
Eiden
Lee E
LE
Vaudry
Hubert
H
Anouar
Youssef
Y
D000818:Animals; D002417:Cattle; D002467:Cell Nucleus / Q000187:drug effects / Q000378:metabolism; D002478:Cells, Cultured; D019439:Chromaffin Cells / Q000187:drug effects / Q000378:metabolism; D003513:Cycloheximide / Q000494:pharmacology; D004789:Enzyme Activation; D007375:Interleukin-1 / Q000494:pharmacology*; D020928:Mitogen-Activated Protein Kinases / Q000187:drug effects / Q000378:metabolism*; D016328:NF-kappa B / Q000187:drug effects / Q000378:metabolism; D009479:Neuropeptides / Q000187:drug effects / Q000235:genetics* / Q000378:metabolism; D047889:Receptors, Tumor Necrosis Factor, Type II / Q000187:drug effects / Q000378:metabolism; D018808:Transcription Factor AP-1 / Q000187:drug effects / Q000378:metabolism*; D014158:Transcription, Genetic; D014409:Tumor Necrosis Factor-alpha / Q000494:pharmacology*
D007375:Interleukin-1; D016328:NF-kappa B; D009479:Neuropeptides; D047889:Receptors, Tumor Necrosis Factor, Type II; D018808:Transcription Factor AP-1; D014409:Tumor Necrosis Factor-alpha; D003513:Cycloheximide; D020928:Mitogen-Activated Protein Kinases