title: Nuclear factor-kappa β regulates Notch signaling in production of proinflammatory cytokines and nitric oxide in murine BV-2 microglial cells.
abstract: Microglial cells exhibit Notch-1 signaling expression which is enhanced upon activation. We reported previously that enhanced Notch-1 expression in activated microglia modulates production of proinflammatory cytokines and nitric oxide (NO). Furthermore, Notch-1 modulates transcription factor nuclear factor-kappa B (NF-κB). This study was aimed to investigate if NF-κB reciprocally modulates Notch signaling in BV-2 cells. In this connection, the cells were pretreated with caffeic acid phenethyl ester (Cape) followed by stimulating the cells with lipopolysaccharide (LPS). Cape+LPS treatment resulted in reduced translocation of NF-κB into the nucleus. Concomitantly, NF-κB DNA binding activity and the mRNA and protein expression levels of NF-κB/p65, Notch-1, intracellular domain of Notch-1 receptor (NICD), Hes-1, tumor necrosis factor-alpha (TNF-α), interleukin-1 beta (IL-1β) and inducible nitric oxide synthase (iNOS) along with nitrite level were significantly reduced. Additionally, flow cytometry analysis showed a decrease in expression levels of NF-κB/p65, Notch-1, NICD but an increase in that of signal transducers and activators of transcription 3 (Stat3). Furthermore, nuclear Hes-1, phosphorylated Stat3 (p-Stat3) and recombination signal-binding protein 1 for J-Kappa (RBP-JK) expression levels were significantly suppressed. The present results suggest that Cape inhibits NF-κB activation through suppressing its interaction with DNA. Cape-induced reduction of Hes-1 may be attributed to decreased interaction between NICD and RBP-JK whose levels were reduced concurrently. Hes-1 reduction may lead to decreased production of inflammatory cytokines and NO. It is concluded that NF-κB can modulate Notch-1 signaling. Both pathways operate synergistically for production of proinflammatory cytokines and NO in activated microglia.
authors: Department of Anatomy, Block MD 10, 4 Medical Drive, Yong Loo Lin School of Medicine, National University of Singapore, Singapore 117597.
authors: Q
authors: Q
authors: Cao
authors: C
authors: C
authors: Kaur
authors: C-Y
authors: CY
authors: Wu
authors: J
authors: J
authors: Lu
authors: E-A
authors: EA
authors: Ling
mesh_terms: D000818:Animals; D015153:Blotting, Western; D002109:Caffeic Acids / Q000494:pharmacology; D002460:Cell Line; D002469:Cell Separation; D016207:Cytokines / Q000096:biosynthesis*; D003603:Cytotoxins / Q000494:pharmacology; D005434:Flow Cytometry; D005455:Fluorescent Antibody Technique; D007249:Inflammation / Q000378:metabolism; D051379:Mice; D017628:Microglia / Q000378:metabolism*; D016328:NF-kappa B / Q000378:metabolism*; D009569:Nitric Oxide / Q000096:biosynthesis*; D010626:Phenylethyl Alcohol / Q000031:analogs & derivatives / Q000494:pharmacology; D060888:Real-Time Polymerase Chain Reaction; D051880:Receptors, Notch / Q000378:metabolism*; D020133:Reverse Transcriptase Polymerase Chain Reaction; D015398:Signal Transduction / Q000502:physiology*
chemical_list: D002109:Caffeic Acids; D016207:Cytokines; D003603:Cytotoxins; D016328:NF-kappa B; D051880:Receptors, Notch; D009569:Nitric Oxide; C055494:caffeic acid phenethyl ester; D010626:Phenylethyl Alcohol