Granulocyte colony-stimulating factor-induced activation of protein kinase-C in myeloid cells

✍ Scribed by Rajendra V. Deshpande; Robert H.F. Peterson; Malcolm A.S. Moore

• Publisher: John Wiley and Sons
• Year: 1997
• Tongue: English
• Weight: 167 KB
• Volume: 66
• Category: Article
• ISSN: 0730-2312
• DOI: 10.1002/(sici)1097-4644(19970901)66:3<286::aid-jcb2>3.0.co;2-l

✦ Synopsis

Granulocyte colony stimulating factor (G-CSF) regulates survival, proliferation, differentiation, and activation of myeloid cells. It binds to a high affinity receptor (G-CSF-R) expressed on myeloid cells, for which the signal transduction mechanisms other than protein tyrosine kinase (PTK) activation have not been completely identified. We explored the potential involvement of protein kinase-C (PKC) in G-CSF-R signal transduction. In this report, we provide direct evidence of PKC activation by G-CSF-R. G-CSF treatment of peripheral blood neutrophils, granulocytic cell lines (HL-60, NFS-60, KG-1), and monocytic cell lines (WEHI-3B,U-937) resulted in PKC activation. Chelerythrine chloride and HA-100, an isoquinolinesulfonamide derivative, the specific inhibitors of PKC, 1,2-Bis(2-aminophenoxy)ethane-N,N,N8,N8-tetra-acetic acid (BAPTA), a chelator of intracellular calcium, and 3,4,5-trimethoxybenzoic acid 8-(diethylamino)-octyl ester (TMB-8), an inhibitor of intracellular calcium release, blocked G-CSF-induced PKC activation in HL-60 cells, and reduced CD11b upregulation in neutrophils, but did not affect ligand-binding or down-modulation of G-CSF-R. Methyl 2,5-dihydroxycinnamate (MDHC), a potent inhibitor of protein tyrosine kinases (PTK), also inhibited PKC activation in response to G-CSF treatment, suggesting that PKC activation may occur downstream of PTK activation. Our results demonstrate the involvement of PKC in G-CSF-R signal transduction, and suggest a common signaling pathway in myeloid cells of granulocytic and monocytic lineages.