ag-490 and rottlerin

We previously reported that prolactin (PRL) induces chitotriosidase (CHIT-1) mRNA expression in human macrophages. In this investigation we determined the signaling pathways involved in CHIT-1 induction in response to PRL. The CHIT-1 induction PRL-mediated was reduced by wortmannin and LY-294002, inhibitors of phosphatidylinositol 3-kinase (PI3-K) and by genistein an inhibitor of protein tyrosine kinase (PTK). Pre-treatment of macrophages with SB203580, a specific inhibitor of the mitogen-activated kinases (MAPK) p38, or with U0126, an inhibitor of MAPK p44/42, prevented both basal and exogenous PRL-mediated CHIT-1 expression. No significant effects on CHIT-1 induction PRL-mediated were observed with a protein kinase C inhibitor (PKC), rottlerin, or with an Src inhibitor, PP2, or with JAK2 inhibitor, AG490. In addition, PRL induced a phosphorylation of AKT that was prevented both by the two MAPK inhibitors SB203580 and U0126 and by the PI3-K inhibitors wortmannin and LY-294002. In conclusion, our results indicate that PRL up-regulated CHIT-1 expression via PTK, PI3-K, MAPK, and signaling transduction components.

Topics: Acetophenones; Benzopyrans; Butadienes; Chromones; Gene Expression Regulation, Enzymologic; Genistein; Hexosaminidases; Humans; Imidazoles; Macrophages; MAP Kinase Signaling System; Monocytes; Morpholines; Nitriles; Phosphatidylinositol 3-Kinases; Phosphorylation; Prolactin; Protein-Tyrosine Kinases; Proto-Oncogene Proteins c-akt; Pyridines; Pyrimidines; RNA, Messenger; Tyrphostins

The pro-inflammatory cytokine interleukin-6 (IL-6) together with its soluble receptor (sIL-6R) induces and maintains thermal hyperalgesia. It facilitates the heat-induced release of calcitonin gene-related peptide from rat cutaneous nociceptors in vivo and in vitro. Here we report that exposure of nociceptive neurons to the IL-6-sIL-6R complex or the gp130-stimulating designer IL-6-sIL-6R fusion protein Hyper-IL-6 (HIL-6) resulted in a potentiation of heat-activated inward currents (I(heat)) and a shift of activation thresholds towards lower temperatures without affecting intracellular calcium levels. The Janus tyrosine kinase inhibitor AG490, the selective protein kinase C (PKC) inhibitor, bisindolylmaleimide 1 (BIM1), as well as rottlerin, a selective blocker of the PKCdelta isoform, but not the cyclooxygenase inhibitor indomethacin, effectively reduced the effect. Reverse transcription-polymerase chain reaction (RT-PCR) and in situ hybridization revealed expression of mRNA for the signal-transducing beta subunit of the receptor gp130 in neuronal somata, rather than satellite cells in rat dorsal root ganglia. Together, the results suggest that IL-6-sIL-6R acts directly on sensory neurons. It increases their susceptibility to noxious heat via the gp130/Jak/PKCdelta signalling pathway.

Topics: Acetophenones; Animals; Antigens, CD; Benzopyrans; Calcium; Cells, Cultured; Cyclooxygenase Inhibitors; Cytokine Receptor gp130; Female; Ganglia, Spinal; Hot Temperature; In Situ Hybridization; Indoles; Indomethacin; Interleukin-6; Janus Kinase 1; Maleimides; Membrane Glycoproteins; Neurons, Afferent; Protein Kinase C; Protein Kinase C-delta; Protein-Tyrosine Kinases; Rats; Rats, Wistar; Receptors, Interleukin-6; Recombinant Fusion Proteins; Reverse Transcriptase Polymerase Chain Reaction; RNA, Messenger; Sensory Thresholds; Signal Transduction; Tyrphostins