scholarly journals Serum amyloid A protein enhances the activity of secretory non-pancreatic phospholipase A2

1995 ◽  
Vol 309 (2) ◽  
pp. 461-464 ◽  
Author(s):  
W Pruzanski ◽  
F C de Beer ◽  
M C de Beer ◽  
E Stefanski ◽  
P Vadas
Keyword(s):  
Phospholipase A2 ◽  
Acute Phase ◽  
Serum Amyloid A ◽  
Acute Phase Proteins ◽  
Lipolytic Activity ◽  
Lipoprotein Metabolism ◽  
Serum Amyloid ◽  
Dependent Manner ◽  
Amyloid A ◽  
Serum Amyloid A Protein

The acute-phase proteins serum amyloid A protein (SAA) and secretory phospholipase A2 (sPLA2) are simultaneously expressed during inflammatory conditions. SAA associates with high-density lipoprotein (HDL) altering its physicochemical composition. We found that purified acute-phase SAA, but not the constitutive form, markedly enhances the lipolytic activity of sPLA2 in a dose-related manner with phosphatidylcholine/lysophosphatidylcholine or phosphatidylethanolamine/lysophosphatidylethanolamine liposomal substrates. Normal HDL was found to reduce activity of sPLA2 in a dose-dependent manner, but when acute-phase HDL containing 27% SAA was tested, it enhanced sPLA2 activity. Immunopurified monospecific antibodies against SAA completely abolished the enhancing activity of SAA and acute-phase HDL. Given the central role of HDL in lipoprotein metabolism, the interaction between HDL, SAA and sPLA2 may account for changes detected in lipoprotein metabolism during the acute phase.

The acute phase response and C-reactive protein

2020 ◽  
pp. 2199-2207
Author(s):  
Mark B. Pepys
Keyword(s):  
Acute Phase ◽  
Acute Phase Response ◽  
Serum Amyloid A ◽  
Acute Phase Proteins ◽  
Phase Response ◽  
Serum Amyloid ◽  
C Reactive Protein ◽  
Reactive Protein ◽  
Amyloid A ◽  
Serum Amyloid A Protein

The acute phase response—trauma, tissue necrosis, infection, inflammation, and malignant neoplasia induce a complex series of nonspecific systemic, physiological, and metabolic responses including fever, leucocytosis, catabolism of muscle proteins, greatly increased de novo synthesis and secretion of a number of ‘acute phase’ plasma proteins, and decreased synthesis of albumin, transthyretin, and high- and low-density lipoproteins. The altered plasma protein concentration profile is called the acute phase response. Acute phase proteins—these are mostly synthesized by hepatocytes, in which transcription is controlled by cytokines including interleukin 1, interleukin 6, and tumour necrosis factor. The circulating concentrations of complement proteins and clotting factors increase by up to 50 to 100%; some of the proteinase inhibitors and α‎1-acid glycoprotein can increase three- to fivefold; but C-reactive protein (CRP) and serum amyloid A protein (an apolipoprotein of high-density lipoprotein particles) are unique in that their concentrations can change by more than 1000-fold. C-reactive protein—this consists of five identical, nonglycosylated, noncovalently associated polypeptide subunits. It binds to autologous and extrinsic materials which contain phosphocholine, including bacteria and their products. Ligand-bound CRP activates the classical complement pathway and triggers the inflammatory and opsonizing activities of the complement system, thereby contributing to innate host resistance to pneumococci and probably to recognition and safe ‘scavenging’ of cellular debris. Clinical features—(1) determination of CRP in serum or plasma is the most useful marker of the acute phase response in most inflammatory and tissue damaging conditions. (2) Acute phase proteins may be harmful in some circumstances. Sustained increased production of serum amyloid A protein can lead to the deposition of AA-type, reactive systemic amyloid.

scholarly journals Serum amyloid A is a positive acute phase protein in Russian sturgeon challenged with Aeromonas hydrophila

2020 ◽  
Vol 10 (1) ◽  
Author(s):  
Mauricio Castellano ◽  
Valeria Silva-Álvarez ◽  
Marcio Aversa-Marnai ◽  
María Lamas-Bervejillo ◽  
Ignacio Quartiani ◽  
...  
Keyword(s):  
Acute Phase ◽  
Aeromonas Hydrophila ◽  
Serum Amyloid A ◽  
Acute Phase Proteins ◽  
Mrna Level ◽  
Serum Amyloid ◽  
Amyloid A ◽  
Non Invasive ◽  
Serum Amyloid A Protein ◽  
First Time

AbstractThe immune system of sturgeons, one of the most ancient and economically valuable fish worldwide, is poorly understood. The lack of molecular tools and data about infection biomarkers hinders the possibility to monitor sturgeon health during farming and detect infection outbreaks. To tackle this issue, we mined publicly available transcriptomic datasets and identified putative positive acute-phase proteins (APPs) of Russian sturgeons that could be induced by a bacterial infection and monitored using non-invasive methods. Teleost literature compelled us to focus on five promising candidates: hepcidin, a warm acclimation associated hemopexin, intelectin, serum amyloid A protein (SAA) and serotransferrin. Among them, SAA was the most upregulated protein at the mRNA level in the liver of sturgeons challenged with heat-inactivated or live Aeromonas hydrophila. To assess whether this upregulation yielded increasing SAA levels in circulation, we developed an in-house ELISA to quantify SAA levels in sturgeon serum. Circulating SAA rose upon bacterial challenge and positively correlated with hepatic saa expression. This is the first time serum SAA has been quantified in an Actinopterygii fish. Since APPs vary across different fish species, our work sheds light on sturgeon acute-phase response, revealing that SAA is a positive APP with potential value as infection biomarker.

scholarly journals Two major ruminant acute phase proteins, haptoglobin and serum amyloid A, as serum biomarkers during active sheep scab infestation

2013 ◽  
Vol 44 (1) ◽  
pp. 103 ◽  
Author(s):  
Beth Wells ◽  
Giles T Innocent ◽  
Peter D Eckersall ◽  
Eilidh McCulloch ◽  
Alasdair J Nisbet ◽  
...  
Keyword(s):  
Acute Phase ◽  
Serum Amyloid A ◽  
Acute Phase Proteins ◽  
Serum Biomarkers ◽  
Serum Amyloid ◽  
Sheep Scab ◽  
Amyloid A

Haptoglobin and serum amyloid A in milk and serum during acute and chronic experimentally induced Staphylococcus aureus mastitis

2003 ◽  
Vol 70 (4) ◽  
pp. 379-386 ◽  
Author(s):  
Ulrika Grönlund ◽  
Cecilia Hultén ◽  
Peter D. Eckersall ◽  
Caroline Hogarth ◽  
Karin Persson Waller
Keyword(s):  
Staphylococcus Aureus ◽  
Acute Phase ◽  
Serum Amyloid A ◽  
Acute Phase Proteins ◽  
Chronic Phase ◽  
Subclinical Mastitis ◽  
Serum Amyloid ◽  
Amyloid A ◽  
Healthy Control ◽  
Experimentally Induced

Local and systemic changes in the acute phase proteins, haptoglobin and serum amyloid A (SAA), were studied in six dairy cows during the acute and chronic phases of experimentally induced Staphylococcus aureus mastitis. Haptoglobin and SAA were measured in serum, and in milk from infected and healthy control udder quarters within each cow. Concentrations of haptoglobin and SAA increased rapidly in both serum and milk during the acute phase of mastitis and followed a similar pattern. Significantly raised milk concentrations of SAA were also found during chronic subclinical mastitis. Serum concentrations of SAA also tended to be higher during the chronic phase than pre-infection. Increases in milk haptoglobin and SAA were specific for the infected udder quarters. In conclusion, measurement of SAA in milk samples could be a useful tool in diagnosing mastitis.

scholarly journals Phosphorylation of human serum amyloid A protein by protein kinase C

1988 ◽  
Vol 255 (1) ◽  
pp. 29-34 ◽  
Author(s):  
A E Nel ◽  
M C De Beer ◽  
E G Shephard ◽  
A F Strachan ◽  
M L Vandenplas ◽  
...  
Keyword(s):  
Protein Kinase C ◽  
Protein Kinase ◽  
Acute Phase ◽  
Serum Amyloid A ◽  
Density Lipoprotein ◽  
Acute Phase Reactant ◽  
Serum Amyloid ◽  
Amyloid A ◽  
Kinase C ◽  
Serum Amyloid A Protein

Monokine-induced hepatic secretion of serum amyloid A protein (apo-SAA), an acute-phase reactant, is followed by rapid association with high-density lipoprotein (HDL) in plasma. Plasma clearance of apo-SAA is more rapid than any of the other HDL apolipoproteins. It has been shown that, of the acute-phase HDL3 apolipoproteins, apo-SAA preferentially associates with neutrophil membranes. HDL apolipoproteins have been shown to activate protein kinase C in endothelial cells. We therefore investigated potential phosphorylation of HDL3 apolipoproteins by protein kinase C. Apo-SAA was the only apolipoprotein phosphorylated (Km = 12 mM). Phosphorylation of the apo-SAA-containing HDL3 particle was selective for the more basic isoforms of apo-SAA (pI 7.0, 7.4, 7.5 and 8.0), with more acidic isoforms being phosphorylated when delipidated acute-phase apolipoproteins were used as substrate. However, phosphorylation was not in itself responsible for the establishment of the apo-SAA isoforms.

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