Lipocalin 2 is a choroid plexus acute-phase protein.
Lipocalin 2 (LCN2) is able to sequester iron-loaded bacterial siderophores and, therefore, is known to participate in the mammalian innate immune response. Of notice, LCN2 was shown to display bacteriostatic effects both in in vitro and in vivo. To reach the brain, bacteria must cross the blood-brain or the choroid plexus (CP)/cerebrospinal fluid (CSF) barriers. Additionally, as the CP is responsible for the production of most of the CSF, responses of the CP mediate signaling into the brain. We show here that in conditions of peripheral inflammation, LCN2 behaves as an acute phase protein in the CP. As early as 1 h after lipopolysaccharide peripheral administration, Lcn2 mRNA levels are upregulated, returning to basal levels after 72 h. Increased LCN2 protein is observed in choroidal epithelia and in endothelial cells of blood vessels in the brain parenchyma. Higher levels of LCN2 are also present in the CSF. These observations suggest that expression of LCN2 at the CP/CSF barrier might be bacteriostatic in the brain, avoiding bacteria dissemination within the CSF into the brain parenchyma. This study shows that the LCN2 is produced by the CP as a component of the innate immune response that protects the central nervous system from infection.
Marques
Fernanda
F
Life and Health Sciences Research Institute (ICVS), School of Health Sciences, University of Minho, Campus Gualtar, Braga, Portugal.
Rodrigues
Ana-João
AJ
Sousa
João C
JC
Coppola
Giovanni
G
Geschwind
Daniel H
DH
Sousa
Nuno
N
Correia-Neves
Margarida
M
Palha
Joana A
JA
D000209:Acute-Phase Proteins / Q000032:analysis / Q000235:genetics / Q000276:immunology*; D000818:Animals; D002555:Cerebrospinal Fluid / Q000737:chemistry; D002831:Choroid Plexus / Q000737:chemistry / Q000276:immunology*; D006801:Humans; D007113:Immunity, Innate; D007249:Inflammation; D000071068:Lipocalin-2; D054834:Lipocalins / Q000032:analysis / Q000235:genetics / Q000276:immunology*; D008070:Lipopolysaccharides / Q000494:pharmacology; D008297:Male; D051379:Mice; D008810:Mice, Inbred C57BL; D015513:Oncogene Proteins / Q000032:analysis / Q000235:genetics / Q000276:immunology*; D012333:RNA, Messenger / Q000032:analysis; D015854:Up-Regulation / Q000235:genetics
D000209:Acute-Phase Proteins; D000071068:Lipocalin-2; D054834:Lipocalins; D008070:Lipopolysaccharides; D015513:Oncogene Proteins; D012333:RNA, Messenger; C071332:Lcn2 protein, mouse