scholarly journals Ex Vivo and In Vitro Effect of Serum Amyloid A in the Induction of Macrophage M2 Markers and Efferocytosis of Apoptotic Neutrophils

2015 ◽  
Vol 194 (10) ◽  
pp. 4891-4900 ◽  
Author(s):  
Lei Sun ◽  
Huibin Zhou ◽  
Ziyan Zhu ◽  
Qian Yan ◽  
Lili Wang ◽  
...  
Keyword(s):  
Serum Amyloid A ◽  
Ex Vivo ◽  
Serum Amyloid ◽  
Amyloid A ◽  
Vitro Effect

Abstract 226: Serum Amyloid A Isoforms and the Capacity to Mediate Cholesterol Efflux

2014 ◽  
Vol 34 (suppl_1) ◽  
Author(s):  
Hussein Yassine ◽  
Olgica Trenchevska ◽  
Chad Borges ◽  
Dobrin Nedelkov ◽  
Randall W Nelson ◽  
...  
Keyword(s):  
Cholesterol Efflux ◽  
Serum Amyloid A ◽  
Hdl Cholesterol ◽  
Acute Phase Reactant ◽  
Serum Amyloid ◽  
Amyloid A ◽  
Cholesterol Levels ◽  
Acute Phase Reactant Protein

Serum Amyloid A (SAA) is an acute phase reactant protein that exists in multiple isoforms, can form HDL, and participates in cholesterol efflux. In vitro studies suggest that the SAA 2.1 isoform has an increased capacity to mediate cholesterol efflux compared to the other isoforms. We examined SAA isoforms using a novel mass spectrometric immunoassay (MSIA) and HDL’s cholesterol efflux capacity (via ABCA-1 and SR-BI) in samples from 59 subjects with (n=33) and without type 2 diabetes (n=26). SAA 1.1 levels were detectable in 58, SAA 2.1 in 14 and SAA 2.2 in 36 of the 59 subjects. SAA 2.1 levels significantly correlated with SR-BI cholesterol efflux (r=0.71, p=0.01, n=14), but not ABCA-1 mediated efflux (r=0.1, P=0.1). This correlation was not explained by changes in HDL phospholipids, Apo A-I or HDL cholesterol levels. In contrast, SAA 2.2 or 1.1 levels did not correlate with changes in SR-BI or ABCA-1 mediated efflux. Although the SAA 2.1 isoform is less frequently detected in plasma, our data confirm that it is closely linked with HDL mediated cholesterol efflux, particularly that is SR-BI mediated.

Serum amyloid A stimulates lipoprotein-associated phospholipase A2 expression in vitro and in vivo

2013 ◽  
Vol 228 (2) ◽  
pp. 370-379 ◽  
Author(s):  
Bo Li ◽  
Zhe Dong ◽  
Hui Liu ◽  
Yan-fei Xia ◽  
Xiao-man Liu ◽  
...  
Keyword(s):  
Phospholipase A2 ◽  
Serum Amyloid A ◽  
Serum Amyloid ◽  
Amyloid A

scholarly journals Serum amyloid A induces G-CSF expression and neutrophilia via Toll-like receptor 2

Blood ◽  
2009 ◽  
Vol 113 (2) ◽  
pp. 429-437 ◽  
Author(s):  
Rong L. He ◽  
Jian Zhou ◽  
Crystal Z. Hanson ◽  
Jia Chen ◽  
Ni Cheng ◽  
...  
Keyword(s):  
Serum Amyloid A ◽  
Inflammatory Diseases ◽  
Serum Amyloid ◽  
Proteinase K ◽  
In Vivo Studies ◽  
Toll Like Receptor ◽  
Amyloid A ◽  
Toll Like Receptor 2

Abstract The acute-phase protein serum amyloid A (SAA) is commonly considered a marker for inflammatory diseases; however, its precise role in inflammation and infection, which often result in neutrophilia, remains ambiguous. In this study, we demonstrate that SAA is a potent endogenous stimulator of granulocyte colony-stimulated factor (G-CSF), a principal cytokine-regulating granulocytosis. This effect of SAA is dependent on Toll-like receptor 2 (TLR2). Our data demonstrate that, in mouse macrophages, both G-CSF mRNA and protein were significantly increased after SAA stimulation. The induction of G-CSF was blocked by an anti-TLR2 antibody and markedly decreased in the TLR2-deficient macrophages. SAA stimulation results in the activation of nuclear factor–κB and binding activity to the CK-1 element of the G-CSF promoter region. In vitro reconstitution experiments also support that TLR2 mediates SAA-induced G-CSF expression. In addition, SAA-induced secretion of G-CSF was sensitive to heat and proteinase K treatment, yet insensitive to polymyxin B treatment, indicating that the induction is a direct effect of SAA. Finally, our in vivo studies confirmed that SAA treatment results in a significant increase in plasma G-CSF and neutrophilia, whereas these responses are ablated in G-CSF– or TLR2-deficient mice.

scholarly journals NFkB Inhibition Mitigates Serum Amyloid A-Induced Pro-Atherogenic Responses in Endothelial Cells and Leukocyte Adhesion and Adverse Changes to Endothelium Function in Isolated Aorta

2018 ◽  
Author(s):  
Abigail Vallejo ◽  
Belal Chami ◽  
Joanne M. Dennis ◽  
Martin Simone ◽  
Gulfam Ahmad ◽  
...  
Keyword(s):  
Gene Expression ◽  
Endothelial Cells ◽  
Vascular Function ◽  
Serum Amyloid A ◽  
Ex Vivo ◽  
Early Stage ◽  
Leukocyte Adhesion ◽  
Serum Amyloid ◽  
Amyloid A ◽  
Isolated Aorta

The acute phase protein serum amyloid A (SAA) is associated with endothelial dysfunction and early-stage atherogenesis. Stimulation of vascular cells with SAA increases gene expression of pro-inflammation cytokines and tissue factor (TF). Activation of the transcription factor, nuclear factor kappa-B (NFkB), may be central to SAA-mediated endothelial cell inflammation, dysfunction and pro-thrombotic responses, while targeting NFkB with a pharmacologic inhibitor, BAY11-7082, may mitigate SAA activity. Human carotid artery endothelial cells (HCtAEC) were pre-incubated (1.5 h) with 10 µM BAY11-7082 or vehicle (control) followed by SAA (10 μg/mL; 4.5 h). Under these conditions gene expression for TF and TNF increased in SAA-treated HCtAEC and pre-treatment with BAY11-7082 significantly (TNF) and marginally (TF) reduced mRNA expression. Intracellular TNF and IL-6 protein also increased in HCtAEC supplemented with SAA and this expression was inhibited by BAY11-7082. Supplemented BAY11-7082 also significantly decreased SAA-mediated leukocyte adhesion to apolipoprotein E-deficient mouse aorta in ex vivo vascular flow studies. In vascular function studies, isolated aortic rings pre-treated with BAY11-7082 prior to incubation with SAA showed improved endothelium-dependent vasorelaxation and increased vascular cGMP content. Together these data suggest that inhibition of NFkB activation may protect endothelial function by inhibiting the pro-inflammatory and pro-thrombotic activities of SAA.

scholarly journals Acute Serum Amyloid A Induces Migration, Angiogenesis, and Inflammation in Synovial Cells In Vitro and in a Human Rheumatoid Arthritis/SCID Mouse Chimera Model

2010 ◽  
Vol 184 (11) ◽  
pp. 6427-6437 ◽  
Author(s):  
Mary Connolly ◽  
Alessandra Marrelli ◽  
Mark Blades ◽  
Jennifer McCormick ◽  
Paola Maderna ◽  
...  
Keyword(s):  
Rheumatoid Arthritis ◽  
Scid Mouse ◽  
Serum Amyloid A ◽  
Serum Amyloid ◽  
Human Rheumatoid Arthritis ◽  
Synovial Cells ◽  
Amyloid A

scholarly journals Serum amyloid A gene expression under acute-phase conditions involves participation of inducible C/EBP-beta and C/EBP-delta and their activation by phosphorylation.

1994 ◽  
Vol 14 (6) ◽  
pp. 4324-4332 ◽  
Author(s):  
A Ray ◽  
B K Ray
Keyword(s):  
Gene Expression ◽  
Dna Binding ◽  
Serum Amyloid A ◽  
Binding Activity ◽  
Serum Amyloid ◽  
Phosphatase Inhibitors ◽  
Amyloid A ◽  
Dna Binding Activity ◽  
Inflammatory Stimuli

Serum amyloid A (SAA) is a plasma protein whose synthesis is markedly increased in the liver during the inflammatory process. Previous analysis of SAA promoter function implicated the involvement of the CCAAT/enhancer-binding protein (C/EBP) in controlling this process. In this study, using antibodies against three C/EBP isoforms in DNA-binding and Western blot (immunoblot) assays, we found that in response to inflammatory signals, both C/EBP-delta and C/EBP-beta are induced and that their interactions with the SAA promoter element are necessary for the increased SAA gene expression. Cotransfections of liver cells with an SAA promoter-linked reporter chloramphenicol acetyltransferase gene and murine sarcoma virus-expressed C/EBP-delta or C/EBP-beta confirm such phenomena. The increased transactivating ability in the presence of the cellular phosphatase inhibitors okadaic acid and sodium orthovanadate, coupled with the observation that dephosphorylation severely inhibits the DNA-binding ability in vitro, implicates a role of phosphorylation in the regulation of the activities of the C/EBP-delta isoform. Consistent with these findings, we have detected higher levels of DNA-binding activity of C/EBP-delta prepared from cells treated with phosphatase inhibitors. We also present evidence that C/EBP-delta is a phosphoprotein. These results suggest that C/EBP-delta is regulated by phosphorylation and, in conjunction with C/EBP-beta, is one of the major proteins responsible for the increased transcription of the SAA gene in response to inflammatory stimuli.

Ribozyme mediated cleavage of acute phase serum amyloid A (A-SAA) mRNA in vitro

FEBS Letters ◽  
1995 ◽  
Vol 374 (2) ◽  
pp. 241-245 ◽  
Author(s):  
Derval J. Gaughan ◽  
Diana M. Steel ◽  
Alexander S. Whitehead
Keyword(s):  
Acute Phase ◽  
Serum Amyloid A ◽  
Serum Amyloid ◽  
Amyloid A ◽  
Acute Phase Serum

scholarly journals Lipopolysaccharide signaling induces serum amyloid A (SAA) synthesis in human hepatocytes in vitro

FEBS Letters ◽  
2004 ◽  
Vol 569 (1-3) ◽  
pp. 235-239 ◽  
Author(s):  
Kiyoshi Migita ◽  
Seigo Abiru ◽  
Minoru Nakamura ◽  
Atsumasa Komori ◽  
Yuki Yoshida ◽  
...  
Keyword(s):  
Serum Amyloid A ◽  
Human Hepatocytes ◽  
Serum Amyloid ◽  
Amyloid A
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