Apolipoprotein A-I glycation by glucose and reactive aldehydes alters phospholipid affinity but not cholesterol export from lipid-laden macrophages
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Apolipoprotein A-I glycation by glucose and reactive aldehydes alters phospholipid affinity but not cholesterol export from lipid-laden macrophages. / Brown, Bronwyn E; Nobecourt, Estelle; Zeng, Jingmin; Jenkins, Alicia J; Rye, Kerry-Anne; Davies, Michael Jonathan.
In: PLOS ONE, Vol. 8, No. 5, 2013, p. e65430.Research output: Contribution to journal › Journal article › peer-review
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TY - JOUR
T1 - Apolipoprotein A-I glycation by glucose and reactive aldehydes alters phospholipid affinity but not cholesterol export from lipid-laden macrophages
AU - Brown, Bronwyn E
AU - Nobecourt, Estelle
AU - Zeng, Jingmin
AU - Jenkins, Alicia J
AU - Rye, Kerry-Anne
AU - Davies, Michael Jonathan
PY - 2013
Y1 - 2013
N2 - Increased protein glycation in people with diabetes may promote atherosclerosis. This study examined the effects of non-enzymatic glycation on the association of lipid-free apolipoproteinA-I (apoA-I) with phospholipid, and cholesterol efflux from lipid-loaded macrophages to lipid-free and lipid-associated apoA-I. Glycation of lipid-free apoA-I by methylglyoxal and glycolaldehyde resulted in Arg, Lys and Trp loss, advanced glycation end-product formation and protein cross-linking. The association of apoA-I glycated by glucose, methylglyoxal or glycolaldehyde with phospholipid multilamellar vesicles was impaired in a glycating agent dose-dependent manner, with exposure of apoA-I to both 30 mM glucose (42% decrease in kslow) and 3 mM glycolaldehyde (50% decrease in kfast, 60% decrease in kslow) resulting is significantly reduced affinity. Cholesterol efflux to control or glycated lipid-free apoA-I, or discoidal reconstituted HDL containing glycated apoA-I (drHDL), was examined using cholesterol-loaded murine (J774A.1) macrophages treated to increase expression of ATP binding cassette transporters A1 (ABCA1) or G1 (ABCG1). Cholesterol efflux from J774A.1 macrophages to glycated lipid-free apoA-I via ABCA1 or glycated drHDL via an ABCG1-dependent mechanism was unaltered, as was efflux to minimally modified apoA-I from people with Type 1 diabetes, or controls. Changes to protein structure and function were prevented by the reactive carbonyl scavenger aminoguanidine. Overall these studies demonstrate that glycation of lipid-free apoA-I, particularly late glycation, modifies its structure, its capacity to bind phospholipids and but not ABCA1- or ABCG1-dependent cholesterol efflux from macrophages.
AB - Increased protein glycation in people with diabetes may promote atherosclerosis. This study examined the effects of non-enzymatic glycation on the association of lipid-free apolipoproteinA-I (apoA-I) with phospholipid, and cholesterol efflux from lipid-loaded macrophages to lipid-free and lipid-associated apoA-I. Glycation of lipid-free apoA-I by methylglyoxal and glycolaldehyde resulted in Arg, Lys and Trp loss, advanced glycation end-product formation and protein cross-linking. The association of apoA-I glycated by glucose, methylglyoxal or glycolaldehyde with phospholipid multilamellar vesicles was impaired in a glycating agent dose-dependent manner, with exposure of apoA-I to both 30 mM glucose (42% decrease in kslow) and 3 mM glycolaldehyde (50% decrease in kfast, 60% decrease in kslow) resulting is significantly reduced affinity. Cholesterol efflux to control or glycated lipid-free apoA-I, or discoidal reconstituted HDL containing glycated apoA-I (drHDL), was examined using cholesterol-loaded murine (J774A.1) macrophages treated to increase expression of ATP binding cassette transporters A1 (ABCA1) or G1 (ABCG1). Cholesterol efflux from J774A.1 macrophages to glycated lipid-free apoA-I via ABCA1 or glycated drHDL via an ABCG1-dependent mechanism was unaltered, as was efflux to minimally modified apoA-I from people with Type 1 diabetes, or controls. Changes to protein structure and function were prevented by the reactive carbonyl scavenger aminoguanidine. Overall these studies demonstrate that glycation of lipid-free apoA-I, particularly late glycation, modifies its structure, its capacity to bind phospholipids and but not ABCA1- or ABCG1-dependent cholesterol efflux from macrophages.
KW - ATP-Binding Cassette Transporters
KW - Adult
KW - Aldehydes
KW - Animals
KW - Apolipoprotein A-I
KW - Biological Transport
KW - Case-Control Studies
KW - Cell Line
KW - Cholesterol
KW - Diabetes Mellitus, Type 1
KW - Female
KW - Glucose
KW - Glycosylation
KW - Humans
KW - Lipid Metabolism
KW - Lipoproteins, HDL
KW - Macrophages
KW - Male
KW - Mice
KW - Phospholipids
KW - Young Adult
U2 - 10.1371/journal.pone.0065430
DO - 10.1371/journal.pone.0065430
M3 - Journal article
C2 - 23741493
VL - 8
SP - e65430
JO - PLoS ONE
JF - PLoS ONE
SN - 1932-6203
IS - 5
ER -
ID: 128974281