The acute phase response in apolipoprotein A-1 knockout mice: apolipoprotein serum amyloid A and lipid distribution in plasma high density lipoproteins

Hajri, Tahar; Elliott-Bryant, Rosemary; Sipe, Jean D.; Liang, J S; Hayes, K. C.; Cathcart, Edgar S.

doi:10.1016/s0005-2760(98)00109-x

Cited by 14 publications

(9 citation statements)

References 35 publications

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“…Because it has been shown that SAA can also exist in vivo in lipid-free form, it is plausible that at high SAA concentrations (up to 1-2 mg/ml (4)) present during inflammation, lipid-free SAA might exist in an oligomeric non-HDL binding state for functional reasons (34). This reasoning is consistent with a study showing that after an acute phase reaction in mice, SAA was found to be circulating free in serum in addition to being HDL-bound (35,36). Thus, the structural malleability of SAA1.1 and SAA2.2 we observed in vitro may reflect the in vivo properties of SAA proteins to allow the regulation of their many putative functions related to cholesterol metabolism and the inflammatory responses (34).…”

Section: Discussionsupporting

confidence: 74%

Pathogenic Serum Amyloid A 1.1 Shows a Long Oligomer-rich Fibrillation Lag Phase Contrary to the Highly Amyloidogenic Non-pathogenic SAA2.2

Srinivasan

Patke

Wang

et al. 2013

Journal of Biological Chemistry

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Background: Murine SAA1.1 is pathogenic and SAA2.2 is non-pathogenic in AA amyloidosis. Results: SAA1.1 and SAA2.2 exhibit different biophysical properties, including fibrillation kinetics and fibril morphology. Conclusion:The distinct biophysical properties of highly homologous SAA proteins may contribute to their different pathogenicity during chronic inflammation. Significance: Structural and kinetic factors, more than their intrinsic amyloidogenicity, may determine the diverse pathogenicity among nearly identical SAA isoforms.

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Section: Discussionsupporting

confidence: 74%

Pathogenic Serum Amyloid A 1.1 Shows a Long Oligomer-rich Fibrillation Lag Phase Contrary to the Highly Amyloidogenic Non-pathogenic SAA2.2

Srinivasan

Patke

Wang

et al. 2013

Journal of Biological Chemistry

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“…Normally, the N-terminal amyloidogenic portion of SAA is bound to high-density lipoprotein (HDL), and thus protected from interaction with AA fibrils (36). However, when the serum concentration of this amyloidogenic protein is greatly increased as a result of an inflammatory stimulus, not all SAA molecules are bound to HDL (37), and thus would be free to interact with AA-derived fibril seeds. As a consequence of this interaction, we posit that SAA undergoes a conformational change leading to the formation of oligomeric intermediates, protofibrils, and ever-expanding amyloid deposits.…”

Section: Discussionmentioning

confidence: 99%

Transmissibility of systemic amyloidosis by a prion-like mechanism

Lundmark

Westermark

Nyström

et al. 2002

Proc. Natl. Acad. Sci. U.S.A.

249

213

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3T3-L1 adipocytes were incubated in serum-free media at 37°C with (dashed line) or without (solid line) 100 ng͞ml insulin for 8 h. Isoproterenol (10 M) was then added for the indicated time course at 37°C, and intracellular cAMP was determined by enzyme immunoassay, as described in Materials and Methods. Data are from a typical experiment done in triplicate wells Ϯ SEM and are representative of three separate experiments. (B) 3T3-L1 adipocytes were incubated in serum-free media for 8 h. Where indicated, 100 ng͞ml insulin was added for 15 min before isoproterenol treatment. Cells were then treated with 10 M isoproterenol for 5 min at 37°C, and intracellular cAMP was determined by enzyme immunoassay, as described in Materials and Methods. Data are from a typical experiment done in triplicate wells Ϯ SEM and are representative of three separate experiments.www.pnas.org͞cgi͞doi͞10.1073͞pnas.0630528100 After this, cells were treated with 10 M isoproterenol for 5 min at 37°C. Cells were then washed with PBS at 37°C and restimulated with a second 10 M dose of isoproterenol for an additional 5 min at 37°C; intracellular cAMP was determined by enzyme immunoassay. (B) 3T3-L1 adipocytes were incubated at 37°C in serum-free media for 8 h in the presence (dashed lines) or absence (solid lines) of 100 ng͞ml insulin. Forskolin was added for the final 5 min, and intracellular cAMP levels were determined by enzyme-linked immunoassay. Data are from typical experiments done in triplicate wells and are representative of three separate experiments.

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“…One proposed mechanism is that lipid-free SAA secreted by hepatocytes associates with existing spherical HDL particles through a remodeling process that may involve the displacement of apoA-I ( 10, 30, 31 ). However, induction of an AP response in apoA-I-defi cient mice leads to the formation of large, spherical HDL particles in which >90% of the protein is SAA, suggesting that SAA is capable of sequestering lipid to form HDL in the absence of apoA-I and other apolipoproteins ( 30,31 ). On the other hand, adenoviral vectormediated expression of SAA in apoA-I-defi cient mice in the absence of infl ammation results in circulating SAA that is mostly in a lipid-poor form, suggesting that components of the AP response are required for the biogenesis of SAA-rich HDL in the absence of apoA-I ( 32 ).…”

Section: Ap Human Hdl Is Not a Better Acceptor For Abcg1-dependent Efmentioning

confidence: 99%

ATP binding cassette G1-dependent cholesterol efflux during inflammation

Beer

Jahangiri

et al. 2011

Journal of Lipid Research

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Journal of Lipid Research Volume 52, 2011 345export. Of major importance are transport mechanisms that promote the effl ux of excess cholesterol to extracellular acceptors, i.e., macrophage reverse cholesterol transport (RCT). The removal of excess cholesterol is critical in the vessel wall, where macrophage uptake of lipoproteinderived lipid can lead to a pathological cholesterol load in the absence of suffi cient removal systems. On the basis of studies in mice, two members of the ATP binding cassette (ABC) superfamily of transmembrane transporters, ABCA1 and ABCG1, play critical roles in preventing cholesterol accumulation in macrophages. In mice, combined defi ciency of ABCA1 and ABCG1 in macrophages leads to impaired cellular cholesterol effl ux in vitro and a massive increase in macrophage lipid accumulation in vivo ( 1-3 ). However, the role of ABCG1 in cholesterol effl ux in human monocyte-derived macrophages has recently been questioned ( 4 ). Accumulating evidence suggests that ABCA1 and ABCG1 act through distinct, yet synergistic, mechanisms to promote macrophage RCT. Whereas lipid-poor apolipoproteins serve as extracellular acceptors for ABCA1-mediated phospholipid (PL) and cholesterol effl ux, ABCG1 appears to promote effl ux by redistributing intracellular cholesterol to plasma membrane domains accessible for removal by HDL, but not lipid-poor apolipoprotein A-I (apoA-I) ( 5 ). ABCA1 and ABCG1 may act sequentially to mediate effl ux, such that nascent HDL generated through the lipidation of lipid-poor/free apoA-I by ABCA1 in turn serves as a substrate for cellular cholesterol export through ABCG1 ( 6, 7 Macrophages possess a number of mechanisms to regulate the balance between cholesterol uptake/synthesis and

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The acute phase response in apolipoprotein A-1 knockout mice: apolipoprotein serum amyloid A and lipid distribution in plasma high density lipoproteins

Cited by 14 publications

References 35 publications

Pathogenic Serum Amyloid A 1.1 Shows a Long Oligomer-rich Fibrillation Lag Phase Contrary to the Highly Amyloidogenic Non-pathogenic SAA2.2

Pathogenic Serum Amyloid A 1.1 Shows a Long Oligomer-rich Fibrillation Lag Phase Contrary to the Highly Amyloidogenic Non-pathogenic SAA2.2

Transmissibility of systemic amyloidosis by a prion-like mechanism

ATP binding cassette G1-dependent cholesterol efflux during inflammation

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