Requirement for PLCγ2 in IL-3 and GM-CSF-stimulated MEK/ERK phosphorylation in murine and human hematopoietic stem/progenitor cells

Authors

  • Carlos M.M.P. Leon,

    1. Departamento de Biofísica, Universidade Federal de São Paulo, São Paulo, SP, Brazil
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  • Christiano M.V. Barbosa,

    1. Departamento de Biofísica, Universidade Federal de São Paulo, São Paulo, SP, Brazil
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  • Giselle Z. Justo,

    1. Departamento de Bioquímica, Universidade Federal de São Paulo, São Paulo, SP, Brazil
    2. Departamento de Ciências Biológicas, Universidade Federal de São Paulo, Diadema, SP, Brazil
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  • Primavera Borelli,

    1. Laboratório de Hematologia Experimental, Departamento de Análises Clínicas e Toxicológicas, Faculdade de Ciências Farmacêuticas, Universidade de São Paulo, São Paulo, SP, Brazil
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  • José Dias Resende Junior,

    1. Disciplina de Hematologia e Hemoterapia, Universidade Federal de São Paulo, São Paulo, SP, Brazil
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  • José S.R. de Oliveira,

    1. Disciplina de Hematologia e Hemoterapia, Universidade Federal de São Paulo, São Paulo, SP, Brazil
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  • Alice T. Ferreira,

    1. Departamento de Biofísica, Universidade Federal de São Paulo, São Paulo, SP, Brazil
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  • Edgar J. Paredes-Gamero

    Corresponding author
    1. Departamento de Biofísica, Universidade Federal de São Paulo, São Paulo, SP, Brazil
    2. Departamento de Bioquímica, Universidade Federal de São Paulo, São Paulo, SP, Brazil
    • Departamento de Biofísica, Universidade Federal de São Paulo, Rua Botucatu 862, 2° Andar, Sao Paulo, SP, Brazil.
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  • The authors declare that there are no conflicts of interest.

Abstract

Even though the involvement of intracellular Ca2+ (equation image) in hematopoiesis has been previously demonstrated, the relationship between equation image signaling and cytokine-induced intracellular pathways remains poorly understood. Herein, the molecular mechanisms integrating Ca2+ signaling with the extracellular signal-regulated kinase 1/2 (ERK1/2) pathway in primary murine and human hematopoietic stem/progenitor cells stimulated by IL-3 and GM-CSF were studied. Our results demonstrated that IL-3 and GM-CSF stimulation induced increased inositol 1,4,5-trisphosphate (IP3) levels and equation image release in murine and human hematopoietic stem/progenitor cells. In addition, equation image signaling inhibitors, such as inositol 1,4,5-trisphosphate receptor antagonist (2-APB), PKC inhibitor (GF109203), and CaMKII inhibitor (KN-62), blocked phosphorylation of MEK activated by IL-3 and GM-CSF, suggesting the participation of Ca2+-dependent kinases in MEK activation. In addition, we identify phospholipase Cγ2 (PLCγ2) as a PLCγ responsible for the induction of Ca2+ release by IL-3 and GM-CSF in hematopoietic stem/progenitor cells. Furthermore, the PLCγ inhibitor U73122 significantly reduced the numbers of granulocyte-macrophage colony-forming units after cytokine stimulation. Similar results were obtained in both murine and human hematopoietic stem/progenitor cells. Taken together, these data indicate a role for PLCγ2 and Ca2+ signaling through the modulation of MEK in both murine and human hematopoietic stem/progenitor cells. J. Cell. Physiol. 226: 1780–1792, 2011. © 2010 Wiley-Liss, Inc.

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