16K prolactin induces NF-kappaB activation in pulmonary fibroblasts.
The amino-terminal 16 kDa fragment of prolactin (16K PRL) promotes the expression of the inducible isoform of nitric oxide synthase (iNOS) accompanied by the production of nitric oxide (NO) by rat pulmonary fibroblasts. The present study was designed to elucidate whether the mechanism by which 16K PRL promotes iNOS expression involves the activation of nuclear factor-kappa B (NF-kappaB), a key transcription factor for iNOS induction. 16K PRL stimulated DNA-binding activity of NF-kappaB in pulmonary fibroblasts as demonstrated by gel shift assays. Likewise, fluorescence immunocytochemistry showed that 16K PRL promotes nuclear translocation of the p65 subunit of NF-kappaB. Finally, treatment with 16K PRL induced the degradation of the NF-kappaB inhibitor kappaB-beta (IkappaB-beta), and such degradation was prevented by blocking IkappaB-beta phosphorylation. Altogether, these results show that 16K PRL activates NF-kappaB nuclear translocation via the phosphorylation and degradation of IkappaB-beta. These findings are consistent with NF-kappaB being part of the signal transduction pathway activated by 16K PRL to induce iNOS expression.
Macotela
Y
Y
Instituto de Neurobiología, Universidad Nacional Autónoma de México, Campus UNAM-Juriquilla, Apartado postal 1-1141, Juriquilla-Querétaro, Qro, 76001 México.
Mendoza
C
C
Corbacho
A M
AM
Cosío
G
G
Eiserich
J P
JP
Zentella
A
A
Martínez de la Escalera
G
G
Clapp
C
C
D021581:Active Transport, Cell Nucleus / Q000187:drug effects; D000818:Animals; D000890:Anti-Infective Agents / Q000494:pharmacology; D002478:Cells, Cultured; D024202:Electrophoretic Mobility Shift Assay / Q000379:methods; D004791:Enzyme Inhibitors / Q000494:pharmacology; D005347:Fibroblasts / Q000187:drug effects / Q000378:metabolism*; D005455:Fluorescent Antibody Technique; D051550:I-kappa B Kinase; D020672:I-kappa B Proteins / Q000378:metabolism; D008168:Lung / Q000187:drug effects / Q000378:metabolism*; D016328:NF-kappa B / Q000378:metabolism*; D019001:Nitric Oxide Synthase / Q000378:metabolism; D052247:Nitric Oxide Synthase Type II; D009570:Nitriles; D010446:Peptide Fragments / Q000494:pharmacology; D010766:Phosphorylation; D011388:Prolactin / Q000494:pharmacology*; D017346:Protein Serine-Threonine Kinases / Q000037:antagonists & inhibitors; D051381:Rats; D017207:Rats, Sprague-Dawley; D015398:Signal Transduction / Q000187:drug effects*; D013450:Sulfones; D014409:Tumor Necrosis Factor-alpha / Q000494:pharmacology
D000890:Anti-Infective Agents; C416282:BAY 11-7085; D004791:Enzyme Inhibitors; C083487:I kappa B beta protein; D020672:I-kappa B Proteins; D016328:NF-kappa B; D009570:Nitriles; D010446:Peptide Fragments; D013450:Sulfones; D014409:Tumor Necrosis Factor-alpha; D011388:Prolactin; D019001:Nitric Oxide Synthase; D052247:Nitric Oxide Synthase Type II; C496318:Nos2 protein, rat; D017346:Protein Serine-Threonine Kinases; D051550:I-kappa B Kinase