TY - JOUR
T1 - alpha1-Antitrypsin regulates CD14 expression and soluble CD14 levels in human monocytes in vitro.
AU - Nita, Izabela
AU - Serapinas, Danielius
AU - Janciauskiene, Sabina
PY - 2007
Y1 - 2007
N2 - The recognition of bacterial lipopolysaccharide (LPS) is principally mediated by either membrane-bound or soluble form of the glycoprotein CD14 and CD14-associated signal transducer, toll-like receptor 4 (TLR4). Recent findings indicate that the serine protease inhibitor, alpha 1-antitrypsin (AAT), may not only afford protection against proteolytic injury, but may also neutralize microbial activities and affect regulation of innate immunity. We postulated that AAT affects monocyte responses to LPS by regulating CD14 expression and soluble CD 14 release. Here we show that a short-term (up to 2 h) monocyte exposure to AAT alone or in combination with LPS leads to a remarkable induction of CD 14 levels. In parallel, a short-term (2 h) cell exposure to AAT/LPS significantly enhances LPS-induced NF kappa B (p50 and p65) activation in conjunction with increased TNF alpha, IL-beta and IL-8 release. In contrast, longer term incubation (18 h) of monocytes with combined AAT/LPS results in a significant reduction in expression of both CD 14 and TLR4, inhibition of LPS-induced TNF alpha, IL-beta and IL-8 mRNA and protein expression. These findings provide evidence that AAT is an important regulator of CD14 expression and release in monocytes and suggest that AAT may be involved in LPS neutralization and prevention of over-activation of monocytes in vivo. (C) 2007 Elsevier Ltd. All rights reserved.
AB - The recognition of bacterial lipopolysaccharide (LPS) is principally mediated by either membrane-bound or soluble form of the glycoprotein CD14 and CD14-associated signal transducer, toll-like receptor 4 (TLR4). Recent findings indicate that the serine protease inhibitor, alpha 1-antitrypsin (AAT), may not only afford protection against proteolytic injury, but may also neutralize microbial activities and affect regulation of innate immunity. We postulated that AAT affects monocyte responses to LPS by regulating CD14 expression and soluble CD 14 release. Here we show that a short-term (up to 2 h) monocyte exposure to AAT alone or in combination with LPS leads to a remarkable induction of CD 14 levels. In parallel, a short-term (2 h) cell exposure to AAT/LPS significantly enhances LPS-induced NF kappa B (p50 and p65) activation in conjunction with increased TNF alpha, IL-beta and IL-8 release. In contrast, longer term incubation (18 h) of monocytes with combined AAT/LPS results in a significant reduction in expression of both CD 14 and TLR4, inhibition of LPS-induced TNF alpha, IL-beta and IL-8 mRNA and protein expression. These findings provide evidence that AAT is an important regulator of CD14 expression and release in monocytes and suggest that AAT may be involved in LPS neutralization and prevention of over-activation of monocytes in vivo. (C) 2007 Elsevier Ltd. All rights reserved.
KW - TLR4
KW - CD14
KW - lipopolysaccharide
KW - alpha 1-antitrypsin
KW - monocytes
KW - inflammation
KW - cytokines
U2 - 10.1016/j.biocel.2007.02.017
DO - 10.1016/j.biocel.2007.02.017
M3 - Article
SN - 1878-5875
VL - 39
SP - 1165
EP - 1176
JO - International Journal of Biochemistry & Cell Biology
JF - International Journal of Biochemistry & Cell Biology
IS - Mar 1
ER -