Induction of FcγRIIA expression in myeloid PLB cells during differentiation depends on cytosolic phospholipase A2 activity and is regulated via activation of CREB by PGE2

Abstract

FcγRIIA expressed on neutrophils and monocytes has a fundamental role in combating bacterial infections. In the present study, the requirement of cytosolic phospholipase A2 (cPLA2) for induction of FcγRIIA expression was studied in a model of cPLA2-deficient PLB-985 cells (PLB-D cells). FcγRIIA was acquired only during differentiation of PLB but not of PLB-D cells induced by either 1,25-dihydroxyvitamin D3, retinoic acid, or interferon γ. Addition of prostaglandin E2 (PGE2) to PLB-D cells undergoing differentiation restored the expression of FcγRIIA protein, whereas addition of indomethacin to PLB cells during differentiation inhibited both the production of PGE2 and the expression of FcγRIIA. Inhibition of PKA during PLB differentiation prevented FcγRIIA expression, whereas dibutyryl cAMP (dbcAMP) induced its expression in both PLB and PLB-D cells. CREB phosphorylation and CREB-CRE interaction were detected only in differentiated PLB cells and not PLB-D cells and were inhibited by indomethacin. A reporter gene containing a FcγRIIA gene promoter fragment with the CRE element was sufficient for CREB activation. Our results are the first to show that CREB activation is involved in up-regulation of FcγRIIA expression in myeloid lineages. PGE2 formed via cPLA2 activates CREB through PKA and this process is dependent on development of PGE2 receptor 4.

Endothelial ICAM-1 Protein Induction Is Regulated by Cytosolic Phospholipase A2α via Both NF-κB and CREB Transcription Factors

“…In our previous studies, we have shown that cPLA 2 a exerts its effect on gene expression and protein upregulation in the leukemic PLB cells (18) and in primary rat microglia (19,31) via the production of PGE 2 . To study whether PGE 2 is involved in TNFa-induced ICAM-1 upregulation in endothelial ECV-304 cells, we first studied the secretion of PGE 2 induced by TNF-a during 24 h. As shown in Fig.…”

“…cDNA was amplified via PCR using Thermus aquaticus DNA polymerase under conditions found to amplify cDNA molecules in a linear fashion. For detection of the Eprostanoid (EP) receptors, we used published primers (10) that were used by us before (19). PCR amplification was performed in a microprocessor-controlled incubation system (Crocodile II; Appligene, Plessanton, CA).…”

“…Nuclear protein extract preparation was performed as previously described (12,19) and analyzed by electrophoresis on 8% SDS-PAGE.…”

Reduction of cPLA2α overexpression: An efficient anti‐inflammatory therapy for collagen‐induced arthritis

“…Immunoblot detection of cPLA 2 and b-actin in peritoneal cell was detected as described previously [40]. Immunoblot detection of cPLA 2 , MPO and b-actin in mouse joints was performed after being frozen in liquid nitrogen, wrapped with aluminium foil and crushed before boiling in lameli buffer.…”

Signalling in Neutrophils: A Retro Look

“…The implication of the heterotrimeric G protein Gs, which is known to be present and active in neutrophils [165,166], in the mediation of the increases of cAMP in neutrophils remains to be investigated. The role of cAMP in dampening neutrophil responses, while generally admitted, is however far from being completely understood as is the cAMPmediated regulation of gene transcription in neutrophils [167,168].…”