Thermal injury and sepsis modulates β-adrenergic receptors and cAMP reponses in monocyte-committed bone marrow cells

We have previously reported that adrenergic stimulation enhances monocytopoiesis following experimental burn injury and sepsis (BI/S). In the present work we measured β-adrenergic receptor number and affinity in bone marrow committed monocyte progenitor cells (CD59+) following BI/S. We find that BI/S treatment significantly decreased monocyte progenitor cell β-adrenergic receptors but significantly increased receptor binding affinity and isoproterenol-stimulated cAMP production. CD14 expression in macrophages derived in vitro from CD59+ cells following BI/S was significantly increased by epinephrine and this change was blocked by β2-adrenergic receptor antagonist. PCR analysis suggests the presence of β2- but not β1-adrenergic receptors. Enhanced adrenergic receptor signaling in CD59+ bone marrow cells following BI/S may be important in macrophage development.