Expression of Notch-1 receptor and its ligands Jagged-1 and Delta-1 in amoeboid microglia in postnatal rat brain and murine BV-2 cells.
Notch-1 receptor signaling pathway is involved in neuronal and glial differentiation. Its involvement in microglial functions, however, has remained elusive. This study reports the localization of Notch-1 receptor immunoreactivity in the amoeboid microglial cells (AMC) in the postnatal rat brain. By immunofluorescence, Notch-1 receptor was colocalized with its ligands, Jagged-1 and Delta-1, in the AMC in the corpus callosum and subventricular zone. Notch-1 immunopositive cells were confirmed to be microglia labeled by OX42 and lectin. Immunoexpression of Notch-1 receptor was progressively reduced with age. Western blot analysis showed that Notch-1 protein level in the corpus callosum in which the AMC were heavily populated was concomitantly decreased. In postnatal rats challenged with lipopolysaccharide (LPS), Notch-1 receptor immunofluorescence in AMC was noticeably enhanced. Furthermore, Notch-1 protein level in the corpus callosum was increased as revealed by Western blotting analysis. In primary microglial culture treated with LPS, mRNA expression of Notch-1 and its ligand Jagged-1 was upregulated but that of Delta-1 was reduced. The expression pattern of Notch-1 and its ligands was confirmed in murine BV-2 cells. Furthermore, Notch-1 neutralization with its antibody reduced its protein expression. More importantly, neutralization of Notch-1 concomitantly suppressed the mRNA expression of IL-6, IL-1, M-CSF, and iNOS; TNF-alpha, mRNA expression, however, was enhanced. Western blot confirmed the changes of protein level of the above except for IL-6, which remained relatively unaltered. It is concluded that Notch-1 signaling in the AMC and LPS-activated microglia/BV-2 cells modulates the expression of proinflammatory cytokines and nitric oxide.
Cao
Qiong
Q
Department of Anatomy, Yong Loo Lin School of Medicine, National University of Singapore, Singapore.
Lu
Jia
J
Kaur
Charanjit
C
Sivakumar
Viswanathan
V
Li
Fan
F
Cheah
Pike See
PS
Dheen
S Thameem
ST
Ling
Eng-Ang
EA
D000818:Animals; D000831:Animals, Newborn; D001921:Brain / Q000254:growth & development* / Q000378:metabolism; D002135:Calcium-Binding Proteins / Q000096:biosynthesis* / Q000235:genetics; D002460:Cell Line; D002478:Cells, Cultured; D016207:Cytokines / Q000096:biosynthesis; D018507:Gene Expression Regulation, Developmental / Q000502:physiology*; D018836:Inflammation Mediators / Q000378:metabolism; D036341:Intercellular Signaling Peptides and Proteins / Q000096:biosynthesis* / Q000235:genetics; D047908:Intracellular Signaling Peptides and Proteins; D000072100:Jagged-1 Protein; D008024:Ligands; D008565:Membrane Proteins / Q000096:biosynthesis* / Q000235:genetics; D051379:Mice; D017628:Microglia / Q000502:physiology*; D017942:Nitric Acid / Q000378:metabolism; D051381:Rats; D017208:Rats, Wistar; D051881:Receptor, Notch1 / Q000096:biosynthesis* / Q000235:genetics; D000072099:Serrate-Jagged Proteins
D002135:Calcium-Binding Proteins; D016207:Cytokines; D018836:Inflammation Mediators; D036341:Intercellular Signaling Peptides and Proteins; D047908:Intracellular Signaling Peptides and Proteins; C000606274:Jag1 protein, mouse; C000606275:Jag1 protein, rat; D000072100:Jagged-1 Protein; D008024:Ligands; D008565:Membrane Proteins; C497763:Notch1 protein, rat; D051881:Receptor, Notch1; D000072099:Serrate-Jagged Proteins; C064045:delta protein; D017942:Nitric Acid