cAMP effects on microglia and macrophages polarization to pro-inflammatory or anti-inflammatory phenotypes

Trabajo presentado en el IV International Congress on Research and Innovation in Neurodegenerative Diseases, celebrado en Alicante, España, del 21 al 23 de septiembre de 2016Peer Reviewe

cAMP effects on polarization of microglia and macrophages to pro-inflammatory or anti-inflammatory phenotypes

Trabajo presentado en el X Simposi de Neurobiologia, celebrado en Barcelona, España, el 6 y 7 de octubre de 2016Peer Reviewe

cAMP effects on polarization of BMDM and RAW264.7 macrophages to proinflammatory or antiinflammatory phenotypes

Trabajo presentado en el Neuroscience 2017, celebrado en Washington del 11 al 15 de noviembre de 2017Infiltrating macrophages are implicated in the neuroinflammatory response in neurodegenerative diseases. There appears to be equilibrium in the lesion site between cells that either exacerbate tissue injury or promote CNS repair. In vitro studies show that this equilibrium can be shifted by chemical stimuli. “Classically activated” M1 macrophages or “M1 spectrum” are considered pro-inflammatory and can be induced by stimuli such as LPS and pro-inflammatory cytokines IFN-gamma or TNF-alpha. The “alternative activation” to M2 macrophages or “M2 spectrum” has anti-inflammatory and tissue reparative phenotype. We studied the influence of cAMP levels on primary Bone Marrow Derived Macrophages (BMDM) and the murine macrophage cell line Raw264.7 to shift to M1 or M2 phenotypes when cells are grown in the presence of pro- or anti-inflammatory stimuli. We tested the implication of different components of the cAMP cascade: adenylyl cyclase, cAMP-PDE4, and PKA. Cells were first pre-incubated 30 min with the different drugs, then stimulated by M1 (10 ng/mL LPS, 20 ng/mL IFN-gamma) or M2 stimuli (20 ng/mL each IL-4/IL-13 for BMDM or 20 ng/mL each IL-4/IL-10 for Raw264.7 for 24 h. Nitric oxide (NO) production or arginase activity were then determined. When BMDM and Raw264.7 cells were pre-treated with the adenylyl cyclase activator forskolin both M1 and M2 cells reverted to M0 phenotype in a concentration-dependent manner. IBMX and some PDE4 inhibitors, rolipram, roflumilast, apremilast and C33 induced a M1 to M0 shift and all potentiated a M2 phenotype in a concentration-dependent manner. cAMP analogs acting on PKA induced a M1 to M2 shift and potentiated the M2 phenotype. In contrast, cAMP analogs acting on Epac did not modify the effects of M1 or M2 stimuli, suggesting that polarization occurs through PKA and not Epac under high cAMP levels. These results were confirmed by immunocytochemistry with phenotype-specific antibodies (iNOS for M1 cells and mannose receptor or arginase 1 for M2 cells). Phenotypic regulation of macrophages with cAMP elevating drugs may be a therapeutic tool for neuroinflammatory diseases.Peer reviewe