TY - JOUR
T1 - The Transcription Factor C/EBP-β Mediates Constitutive and LPS-Inducible Transcription of Murine SerpinB2
AU - Udofa, Ekemini A.
AU - Stringer, Brett W.
AU - Gade, Padmaja
AU - Mahony, Donna
AU - Buzza, Marguerite S.
AU - Kalvakolanu, Dhananjaya V.
AU - Antalis, Toni M.
N1 - Unless otherwise indicated, articles and accompanying materials published by PLOS on the PLOS Sites, including peer reviews, are licensed by the respective authors for use and distribution by you subject to citation of the original source in accordance with the Creative Commons Attribution (CC BY) license.
PY - 2013/3/5
Y1 - 2013/3/5
N2 - SerpinB2 or plasminogen activator inhibitor type 2 (PAI-2) is highly induced in macrophages in response to inflammatory stimuli and is linked to the modulation of innate immunity, macrophage survival, and inhibition of plasminogen activators. Lipopolysaccharide (LPS), a potent bacterial endotoxin, can induce SerpinB2 expression via the toll-like receptor 4 (TLR4) by ~1000-fold over a period of 24 hrs in murine macrophages. To map the LPS-regulated SerpinB2 promoter regions, we transfected reporter constructs driven by the ~5 kb 5'-flanking region of the murine SerpinB2 gene and several deletion mutants into murine macrophages. In addition, we compared the DNA sequence of the murine 5′ flanking sequence with the sequence of the human gene for homologous functional regulatory elements and identified several regulatory cis-acting elements in the human SERPINB2 promoter conserved in the mouse. Mutation analyses revealed that a CCAAT enhancer binding (C/EBP) element, a cyclic AMP response element (CRE) and two activator protein 1 (AP-1) response elements in the murine SerpinB2 proximal promoter are essential for optimal LPS-inducibility. Electrophoretic mobility shift (EMSA) and chromatin immunoprecipitation (ChIP) assays demonstrated that LPS induces the formation of C/EBP-β containing complexes with the SerpinB2 promoter. Importantly, both constitutive and LPS-induced SerpinB2 expression was severely abrogated in C/EBP-β-null mouse embryonic fibroblasts (MEFs) and primary C/EBP-β-deficient peritoneal macrophages. Together, these data provide new insight into C/EBP-β-dependent regulation of inflammation-associated SerpinB2 expression.
AB - SerpinB2 or plasminogen activator inhibitor type 2 (PAI-2) is highly induced in macrophages in response to inflammatory stimuli and is linked to the modulation of innate immunity, macrophage survival, and inhibition of plasminogen activators. Lipopolysaccharide (LPS), a potent bacterial endotoxin, can induce SerpinB2 expression via the toll-like receptor 4 (TLR4) by ~1000-fold over a period of 24 hrs in murine macrophages. To map the LPS-regulated SerpinB2 promoter regions, we transfected reporter constructs driven by the ~5 kb 5'-flanking region of the murine SerpinB2 gene and several deletion mutants into murine macrophages. In addition, we compared the DNA sequence of the murine 5′ flanking sequence with the sequence of the human gene for homologous functional regulatory elements and identified several regulatory cis-acting elements in the human SERPINB2 promoter conserved in the mouse. Mutation analyses revealed that a CCAAT enhancer binding (C/EBP) element, a cyclic AMP response element (CRE) and two activator protein 1 (AP-1) response elements in the murine SerpinB2 proximal promoter are essential for optimal LPS-inducibility. Electrophoretic mobility shift (EMSA) and chromatin immunoprecipitation (ChIP) assays demonstrated that LPS induces the formation of C/EBP-β containing complexes with the SerpinB2 promoter. Importantly, both constitutive and LPS-induced SerpinB2 expression was severely abrogated in C/EBP-β-null mouse embryonic fibroblasts (MEFs) and primary C/EBP-β-deficient peritoneal macrophages. Together, these data provide new insight into C/EBP-β-dependent regulation of inflammation-associated SerpinB2 expression.
UR - http://www.scopus.com/inward/record.url?scp=84874626573&partnerID=8YFLogxK
U2 - 10.1371/journal.pone.0057855
DO - 10.1371/journal.pone.0057855
M3 - Article
C2 - 23472114
AN - SCOPUS:84874626573
SN - 1932-6203
VL - 8
SP - 1
EP - 14
JO - PLoS One
JF - PLoS One
IS - 3
M1 - e57855
ER -