ABCMdb

ABCA1 p.Pro85Leu

Predicted by SNAP2:	A: D (63%), C: D (63%), D: D (75%), E: D (59%), F: D (71%), G: D (71%), H: N (61%), I: D (71%), K: D (53%), L: D (85%), M: D (85%), N: D (71%), Q: N (57%), R: D (59%), S: D (59%), T: N (61%), V: D (66%), W: D (75%), Y: D (66%),
Predicted by PROVEAN:	A: D, C: D, D: D, E: D, F: D, G: D, H: D, I: D, K: D, L: D, M: D, N: D, Q: D, R: D, S: D, T: D, V: D, W: D, Y: D,

[switch to compact view]
Comments [show]

None has been submitted yet.

Publications
[hide] Genetic etiology of isolated low HDL syndrome: inc... Arterioscler Thromb Vasc Biol. 2007 May;27(5):1139-45. Epub 2007 Feb 15. Kiss RS, Kavaslar N, Okuhira K, Freeman MW, Walter S, Milne RW, McPherson R, Marcel YL
Genetic etiology of isolated low HDL syndrome: incidence and heterogeneity of efflux defects.
Arterioscler Thromb Vasc Biol. 2007 May;27(5):1139-45. Epub 2007 Feb 15., [PMID:17303779]

Abstract [show]
OBJECTIVE: We have used a multitiered approach to identify genetic and cellular contributors to high-density lipoprotein (HDL) deficiency in 124 human subjects. METHODS AND RESULTS: We resequenced 4 candidate genes for HDL regulation and identified several functional nonsynonymous mutations including 2 in apolipoprotein A-I (APOA1), 4 in lecithin:cholesterol acyltransferase (LCAT), 1 in phospholipid transfer protein (PLTP), and 7 in the ATP-binding cassette transporter ABCA1, leaving 88% (110/124) of HDL deficient subjects without a genetic diagnosis. Cholesterol efflux assays performed using cholesterol-loaded monocyte-derived macrophages from the 124 low HDL subjects and 48 control subjects revealed that 33% (41/124) of low HDL subjects had low efflux, despite the fact that the majority of these subjects (34/41) were not carriers of dysfunctional ABCA1 alleles. In contrast, only 2% of control subjects presented with low efflux (1/48). In 3 families without ABCA1 mutations, efflux defects were found to cosegregate with low HDL. CONCLUSIONS: Efflux defects are frequent in low HDL syndromes, but the majority of HDL deficient subjects with cellular cholesterol efflux defects do not harbor ABCA1 mutations, suggesting that novel pathways contribute to this phenotype.

Comments [show]

None has been submitted yet.

Sentences [show]
No. Sentence Comment
47 In ABCA1, a total of 19 nonsynonymous coding sequence variants; some of these we reported previously.22 Of these, 9 sequence variants were common polymorphisms (ie, reported in the literature as common or of similar prevalence in control subjects): P85L, P85A, R219K, V399A, V771M, V825I, I883M, E1172D, R1587K.14,32-35 Another 5 sequence variants, identified here, were previously reported to be disease causing: W590L (reported as W590S)14; C1477F (reported as C1477R)13; S1731C (only found in French-Canadian populations)36; N1800H32; and 1851X.37 Five sequence variants were novel: K199F, H551D, R965C, E1386Q, and D1706N. Login to comment
42 In ABCA1, a total of 19 nonsynonymous coding sequence variants; some of these we reported previously.22 Of these, 9 sequence variants were common polymorphisms (ie, reported in the literature as common or of similar prevalence in control subjects): P85L, P85A, R219K, V399A, V771M, V825I, I883M, E1172D, R1587K.14,32-35 Another 5 sequence variants, identified here, were previously reported to be disease causing: W590L (reported as W590S)14; C1477F (reported as C1477R)13; S1731C (only found in French-Canadian populations)36; N1800H32; and 1851X.37 Five sequence variants were novel: K199F, H551D, R965C, E1386Q, and D1706N. Login to comment

[hide] Do mutations causing low HDL-C promote increased c... Clin Chim Acta. 2007 Feb;377(1-2):273-5. Epub 2006 Oct 7. Miller M, Rhyne J, Hong SH, Friel G, Dolinar C, Riley W
Do mutations causing low HDL-C promote increased carotid intima-media thickness?
Clin Chim Acta. 2007 Feb;377(1-2):273-5. Epub 2006 Oct 7., [PMID:17113061]

Abstract [show]
BACKGROUND: Although observational data support an inverse relationship between high-density lipoprotein (HDL) cholesterol and coronary heart disease (CHD), genetic HDL deficiency states often do not correlate with premature CHD. METHODS: Carotid intima-media thickness (cIMT) measurements were obtained in cases comprising 10 different mutations in LCAT, ABCA1 and APOA1 to further evaluate the relationship between low HDL resulting from genetic variation and early atherosclerosis. RESULTS: In a 1:2 case-control study of sex and age-related (+/-5 y) subjects (n=114), cIMT was nearly identical between cases (0.66+/-0.17 cm) and controls (0.65+/-0.18 cm) despite significantly lower HDL cholesterol (0.67 vs. 1.58 mmol/l) and apolipoprotein A-I levels (96.7 vs. 151.4 mg/dl) (P<0.05) CONCLUSIONS: Genetic variants identified in the present study may be insufficient to promote early carotid atherosclerosis.

Comments [show]

None has been submitted yet.

Sentences [show]
No. Sentence Comment
11 Materials and methods We previously identified mutations in LCAT [T321M, C-deletion (codon 168) P260X [7,8], ABCA1 [D1099Y, F2009S, P85L, R1851Q, IVS46: del T-39…-46] [9-11] and APOA1 [L159P] [12]. Login to comment
46 Therefore, while we Table 1 Genetic variants causing low HDL-C Gene Mutation Number Affected Reference LCAT c-deletion (codon 168) 2 [7] T321M 5 [7] P260X 3 [8] I178T 6 [13] ABCA1 D1099Y 5 [9] F2009S 1 [9] P85L 4 [10] R1851Q 6 [11] IVS46: del T-39…-46 6 [11] APOAI L159P 6 [12] Total 41 cases (includes 3 compound heterozygotes) Table 2 Selected demographic factors, risk factor prevalence, medication use and biochemical measurements (mean and SD) and cIMT in genetic variant HDL-C cases and controls Cases (n=41) Controls (n=73) Age (y) 44.8 (20.7) 44.8 (19.1) BMI (kg/m2 ) 28.0 (4.3) 26.4 (4.9) Hypertension (%) 10.8% 15.9% Diabetes mellitus (%) 2.7% 0% Smoking history (%) 24.3% 31.7% Antiplatelet therapy (%) 18.9% 9.7% Lipid lowering therapy (%) 21.6% 12.9% cIMT (mm) 0.66 (0.17) 0.65 (0.18) TC (mmol/l) 4.92 (1.52) 5.03 (1.06) TG (mmol/l) 2.10 (1.72) ⁎ 1.36 (0.90) HDL-C (mmol/l) 0.67 (0.36) ⁎ 1.58 (0.75) LDL-C (mmol/l) 3.28 (1.31) 2.85 (0.91) APOAI (mg/dl) 96.7 (37.9) ⁎ 151.4 (34.9) APOB (mg/dl) 123.6 (44.8) ⁎ 89.9 (26.6) ⁎ Pb0.05 cases vs. controls. Login to comment

[hide] Variations on a gene: rare and common variants in ... Annu Rev Nutr. 2006;26:105-29. Brunham LR, Singaraja RR, Hayden MR
Variations on a gene: rare and common variants in ABCA1 and their impact on HDL cholesterol levels and atherosclerosis.
Annu Rev Nutr. 2006;26:105-29., [PMID:16704350]

Abstract [show]
Cholesterol and its metabolites play a variety of essential roles in living systems. Virtually all animal cells require cholesterol, which they acquire through synthesis or uptake, but only the liver can degrade cholesterol. The ABCA1 gene product regulates the rate-controlling step in the removal of cellular cholesterol: the efflux of cellular cholesterol and phospholipids to an apolipoprotein acceptor. Mutations in ABCA1, as seen in Tangier disease, result in accumulation of cellular cholesterol, reduced plasma high-density lipoprotein cholesterol, and increased risk for coronary artery disease. To date, more than 100 coding variants have been identified in ABCA1, and these variants result in a broad spectrum of biochemical and clinical phenotypes. Here we review genetic variation in ABCA1 and its critical role in cholesterol metabolism and atherosclerosis in the general population.

Comments [show]

None has been submitted yet.

Sentences [show]
No. Sentence Comment
555 Since a complete loss of function allele would be expected to result in a 50% reduction in HDL levels, a greater than 50% reduction in HDL is most likely explained by a dominant negative allele, in which TABLE 3 Patient phenotypes associated with heterozygous ABCA1 mutations Mutation HDL (mmol/L) HDL (% of control) Number of patients M1091T 0.48 ± 0.5 30 ± 30 4 G1216V 0.50 40 1 R2144X 0.56 ± 0.2 41 ± 18 12 R282X 0.52 41 1 R909X 0.59 ± 0.3 42 ± 19 5 K776N 0.55 ± 0.1 47 ± 5 2 R587W 0.61 ± 0.1 47 ± 8 7 S364C 0.60 48 1 P1065S 0.80 51 1 c-ter deletion 0.75 53 1 N1800H - 56.5 33 P85L 0.72 ± 0.4 57 ± 33 5 Del693L 0.79 ± 0.2 57 ± 15 8 D1289N 0.80 ± 0.1 59 ± 12 4 R2081W 0.80 ± 0.1 59 ± 12 4 2203X 0.80 ± 0.2 59 ± 20 4 DelED1893,4 0.77 ± 0.2 59 ± 18 8 2145X 0.82 ± 0.1 59 ± 9 4 A1046D 0.70 ± 0.1 60 ± 8 2 Q597R 0.82 ± 0.1 60 ± 5 5 C1477R 0.82 ± 0.2 61 ± 15 9 IVS25 + 1G > C 0.78 ± 0.1 62 ± 12 4 D1099Y 0.83 ± 0.3 63 ± 21 5 1552X 1.00 64 1 F2009S 0.82 ± 0.2 64 ± 19 6 R587W 0.86 ± 0.1 65 ± 17 2 R1068H 0.90 ± 0.3 67 ± 26 9 N935S 1.00 ± 0.3 74 ± 16 7 T929I 1.01 ± 0.2 76 ± 7 8 1284X 1.11 ± 0.2 83 ± 14 5 A937V 1.15 ± 0.6 85 ± 28 2 R1680W 1.22 ± 0.2 87 ± 17 3 635X 1.24 ± 0.5 90 ± 32 7 W590S 1.32 ± 0.6 103 ± 46 15 the mutant protein actually interferes with the activity of the remaining wild-type protein. Login to comment

[hide] Accurate prediction of the functional significance... PLoS Genet. 2005 Dec;1(6):e83. Epub 2005 Dec 30. Brunham LR, Singaraja RR, Pape TD, Kejariwal A, Thomas PD, Hayden MR
Accurate prediction of the functional significance of single nucleotide polymorphisms and mutations in the ABCA1 gene.
PLoS Genet. 2005 Dec;1(6):e83. Epub 2005 Dec 30., [PMID:16429166]

Abstract [show]
The human genome contains an estimated 100,000 to 300,000 DNA variants that alter an amino acid in an encoded protein. However, our ability to predict which of these variants are functionally significant is limited. We used a bioinformatics approach to define the functional significance of genetic variation in the ABCA1 gene, a cholesterol transporter crucial for the metabolism of high density lipoprotein cholesterol. To predict the functional consequence of each coding single nucleotide polymorphism and mutation in this gene, we calculated a substitution position-specific evolutionary conservation score for each variant, which considers site-specific variation among evolutionarily related proteins. To test the bioinformatics predictions experimentally, we evaluated the biochemical consequence of these sequence variants by examining the ability of cell lines stably transfected with the ABCA1 alleles to elicit cholesterol efflux. Our bioinformatics approach correctly predicted the functional impact of greater than 94% of the naturally occurring variants we assessed. The bioinformatics predictions were significantly correlated with the degree of functional impairment of ABCA1 mutations (r2 = 0.62, p = 0.0008). These results have allowed us to define the impact of genetic variation on ABCA1 function and to suggest that the in silico evolutionary approach we used may be a useful tool in general for predicting the effects of DNA variation on gene function. In addition, our data suggest that considering patterns of positive selection, along with patterns of negative selection such as evolutionary conservation, may improve our ability to predict the functional effects of amino acid variation.

Comments [show]

None has been submitted yet.

Sentences [show]
No. Sentence Comment
48 This SNP has been reported to be associated with decreased HDL cholesterol and increased severity of atherosclerosis in Table 1. subPSEC Scores and Probability of Functional Impairment (Pdeleterious) for ABCA1 Mutations and SNPs Mutations SNPs Variant SubPSEC Pdeleterious Variant subPSEC Pdeleterious P85L À4.62 0.83 R219K À0.57 0.08 H160F À2.79 0.45 V399A À2.26 0.32 R230C À4.27 0.78 V771M À2.86 0.46 A255T À1.81 0.23 T774P À1.99 0.27 E284K À2.34 0.34 K776N À3.53 0.63 Y482C À4.21 0.77 V825I À1.06 0.13 R587W À6.04 0.95 I883M À1.38 0.17 W590S À5.19 0.9 E1172D À1.96 0.26 W590L À4.48 0.82 R1587K À0.58 0.08 Q597R À7.15 0.98 S1731C À4.21 0.77 T929I À4.29 0.78 N935H À8.54 1 N935S À7.53 0.99 A937V À6.6 0.97 A1046D À7.52 0.99 M1091T À3.56 0.64 D1099Y À6.09 0.96 D1289N À2.48 0.37 L1379F À3.81 0.69 C1477R À5.44 0.92 S1506L À5.17 0.9 N1611D À5.69 0.94 R1680W À6.02 0.95 V1704D À3.21 0.55 N1800H À4.23 0.77 R1901S À5.06 0.89 F2009S À2.73 0.43 R2081W À8.08 0.99 P2150L À2.88 0.47 Q2196H À2.74 0.43 DOI: 10.1371/journal.pgen.0010083.t001 PLoS Genetics | www.plosgenetics.org December 2005 | Volume 1 | Issue 6 | e83 0740 Accurate Prediction of ABCA1 Variants Synopsis A major goal of human genetics research is to understand how genetic variation leads to differences in the function of genes. Login to comment
110 DOI: 10.1371/journal.pgen.0010083.g003 Table 3. subPSEC Scores for ABCA1 Variants Described in a Cohort of Individuals with Low HDL Cholesterol from the General Population Variant subPSEC Score Macrophage Efflux PolyPhen D1706N À6.57 0.38a Possibly damaging C1477F À5.55 0.34a Probably damaging W590S À5.19 - Probably damaging H551D À4.99 0.32a Probably damaging P85L À4.62 0.8 Probably damaging W590L À4.48 0.31a Probably damaging N1800H À4.23 0.27a Possibly damaging R965C À4.22 0.59 Probably damaging S1731C À4.21 0.28a Possibly damaging A1670T À4.2 - Possibly damaging K401Q À4.2 - Benign T459P À4.11 0.28a Possibly damaging R638Q À4.08 - Possibly damaging L1026P À3.86 0.25a Benign T2073A À3.84 0.28a Possibly damaging E815G À3.53 - Probably damaging R1615Q À3.45 - Possibly damaging S1181F À3.44 - Possibly damaging R306H À3.31 - Benign E1386Q À2.44 0.51 Benign S1376G À2.19 - Benign R1341T À2.09 - Possibly damaging D2243E À1.6 - Benign P248A À0.18 - Benign a Efflux value is 2 SDs or more below control levels of 0.52 6 0.07. Login to comment

[hide] Efflux and atherosclerosis: the clinical and bioch... Arterioscler Thromb Vasc Biol. 2003 Aug 1;23(8):1322-32. Epub 2003 May 22. Singaraja RR, Brunham LR, Visscher H, Kastelein JJ, Hayden MR
Efflux and atherosclerosis: the clinical and biochemical impact of variations in the ABCA1 gene.
Arterioscler Thromb Vasc Biol. 2003 Aug 1;23(8):1322-32. Epub 2003 May 22., [PMID:12763760]

Abstract [show]
Approximately 50 mutations and many single nucleotide polymorphisms have been described in the ABCA1 gene, with mutations leading to Tangier disease and familial hypoalphalipoproteinemia. Homozygotes and heterozygotes for mutations in ABCA1 display a wide range of phenotypes. Identification of ABCA1 as the molecular defect in these diseases has allowed for ascertainment based on genetic status and determination of genotype-phenotype correlations and has permitted us to identify mutations conferring a range of severity of cellular, biochemical, and clinical phenotypes. In this study we review how genetic variation at the ABCA1 locus affects its role in the maintenance of lipid homeostasis and the natural progression of atherosclerosis.

Comments [show]

None has been submitted yet.

Sentences [show]
No. Sentence Comment
83 TABLE 2. Conservation of Amino Acid Residues Mutated in Humans Mutation H. sapiens M. musculus G. gallus D. melanogaster C. elegans P85L P P P ⅐ ⅐ ⅐ P R230C R R R P G A255T A A S ⅐ ⅐ ⅐ ⅐ ⅐ ⅐ R587W R R R ⅐ ⅐ ⅐ ⅐ ⅐ ⅐ W590S W W W R Q Q597R Q Q Q Q Q ⌬L693 L L L L L T929I T T T T T N935S/H N N N N N A937V A A A A A A1046D A A A A A M1091T M M M M M D1099Y D D D D D D1289L/N D D D D D C1477R C C C ⅐ ⅐ ⅐ ⅐ ⅐ ⅐ S1506L S S S ⅐ ⅐ ⅐ ⅐ ⅐ ⅐ N1611D N N N N S R1680W R R R R R N1800H N N N A W F2009S F F F I M R2081W R R R R R P2150L P P P R N ⌬E1893 E E E D S ⌬D1894 D D D D D Twenty-three of 24 (95.83%) amino acids affected by mutations are conserved with G. gallus, reflecting the functional importance of these residues. Login to comment
75 TABLE 2. Conservation of Amino Acid Residues Mutated in Humans Mutation H. sapiens M. musculus G. gallus D. melanogaster C. elegans P85L P P P ዼ ዼ ዼ P R230C R R R P G A255T A A S ዼ ዼ ዼ ዼ ዼ ዼ R587W R R R ዼ ዼ ዼ ዼ ዼ ዼ W590S W W W R Q Q597R Q Q Q Q Q èc;L693 L L L L L T929I T T T T T N935S/H N N N N N A937V A A A A A A1046D A A A A A M1091T M M M M M D1099Y D D D D D D1289L/N D D D D D C1477R C C C ዼ ዼ ዼ ዼ ዼ ዼ S1506L S S S ዼ ዼ ዼ ዼ ዼ ዼ N1611D N N N N S R1680W R R R R R N1800H N N N A W F2009S F F F I M R2081W R R R R R P2150L P P P R N èc;E1893 E E E D S èc;D1894 D D D D D Twenty-three of 24 (95.83%) amino acids affected by mutations are conserved with G. gallus, reflecting the functional importance of these residues. Login to comment

[hide] A new ABCA1 mutation associated with low HDL chole... Atherosclerosis. 2003 Aug;169(2):345-6; author reply 347-8. Kolovou G, Anagnostopoulou K, Cokkinos DV
A new ABCA1 mutation associated with low HDL cholesterol but without coronary artery disease.
Atherosclerosis. 2003 Aug;169(2):345-6; author reply 347-8., [PMID:12921988]

Abstract [show]

Comments [show]

None has been submitted yet.

Sentences [show]
No. Sentence Comment
0 Letter to the Editor A new ABCA1 mutation associated with low HDL cholesterol but without coronary artery disease We have read with great interest the paper of Seung Ho Hong and associates [1] describing the P85L variant, or ABCA1Alabama , in the ATP-binding cassette transporter (ABCA1) gene, and would like to add some comments and observations that may be of interest. Login to comment
15 Although our patient as well as her parents have a truncated ABCA1 transcript, they have no clinical signs of CAD, while the patient with the P85L variation produces a full length and possibly functional protein, and developed premature CAD which led him to coronary artery bypass grafting at the age of 48 years old. Login to comment

[hide] Genetics of HDL regulation in humans. Curr Opin Lipidol. 2003 Jun;14(3):273-9. Miller M, Rhyne J, Hamlette S, Birnbaum J, Rodriguez A
Genetics of HDL regulation in humans.
Curr Opin Lipidol. 2003 Jun;14(3):273-9., [PMID:12840658]

Abstract [show]
PURPOSE OF REVIEW: To review gene regulation of HDL-cholesterol and discuss molecular abnormalities in HDL candidate genes that may lead to human pathologic states. RECENT FINDINGS: The inverse association between HDL-cholesterol and vascular disease, especially coronary heart disease, has long been recognized, but understanding gene regulation of HDL in humans gained considerable momentum following the identification of ABCA1 as playing a pivotal role in reverse cholesterol transport. Recent data suggest that potentially important targets for upregulating HDL in humans include upregulators of ABCA1 and APOA1 (e.g. peroxisome proliferator activated receptor and liver X receptor agonists) and downregulators of CETP (e.g. JTT-705). A host of other nuclear receptors under investigation in animal models may advance to human testing in the near future. SUMMARY: Disorders affecting HDL metabolism are complex because monogenic disorders causing low HDL do not necessarily correlate with premature vascular disease. To date, pathologic phenotypes have only been deduced among several HDL candidate genes. Understanding the genetic underpinnings associated with variant HDL and reverse cholesterol transport provides an exceptional opportunity to identify novel agents that may optimize this process and reduce vascular event rates beyond currently available LDL lowering therapies.

Comments [show]

None has been submitted yet.

Sentences [show]
No. Sentence Comment
63 FHA 648 C/T 4 P85L extracellular loop # 1 [72.] Login to comment

[hide] ABCA1(Alabama): a novel variant associated with HD... Atherosclerosis. 2002 Oct;164(2):245-50. Hong SH, Rhyne J, Zeller K, Miller M
ABCA1(Alabama): a novel variant associated with HDL deficiency and premature coronary artery disease.
Atherosclerosis. 2002 Oct;164(2):245-50., [PMID:12204794]

Abstract [show]
The ATP-binding cassette transporter, ABCA1, is a member of the ABC superfamily of proteins involved in the active transport of substrates across cellular membranes. Recent studies have implicated mutations in ABCA1 as the cause of Tangier disease (TD) and familial hypoalphalipoproteinemia (FHA). To evaluate the molecular basis of low high density lipoprotein (HDL) in a family with premature coronary artery disease, single strand conformational polymorphism analysis was performed for all coding regions and splice site junctions of ABCA1 with the genomic DNA of the proband. The proband and affected individuals were heterozygotes for C254T with proline converted to leucine (P85L). This mutation was not identified in over 400 chromosomes of healthy subjects. In the FHA kindred, family members heterozygous for the ABCA1 variant also exhibited corresponding low levels of HDL cholesterol. These data confirm recent data that a single defective allele in ABCA1 may be associated with reduced HDL cholesterol and FHA.

Comments [show]

None has been submitted yet.

Sentences [show]
No. Sentence Comment
3 The proband and affected individuals were heterozygotes for C254T with proline converted to leucine (P85L). Login to comment
50 Pedigree of the kindred showing HDL segregation of the P85L mutation. Login to comment
51 Solid symbols indicate heterozygote carrier status for the P85L mutation. Login to comment
73 This mutation changes proline to leucine (P85L). Login to comment
111 Mean plasma lipid levels were compared between carriers ('/) and non-carriers ((/) of the P85L mutation. Login to comment
122 In the present study, the novel mutation (P85L) in ABCA1 was identified in one family with low HDL but was not detected in over 400 chromosomes of healthy subjects. Login to comment
124 The P85L mutation is located in the 5? Login to comment
110 Mean plasma lipid levels were compared between carriers (/) and noncarriers (/) of the P85L mutation. Login to comment
121 In the present study, the novel mutation (P85L) in ABCA1 was identified in one family with low HDL but was not detected in over 400 chromosomes of healthy subjects. Login to comment
123 The P85L mutation is located in the 5? Login to comment

[hide] HDL does not influence the polarization of human m... Int J Cardiol. 2014 Mar 1;172(1):179-84. doi: 10.1016/j.ijcard.2013.12.168. Epub 2014 Jan 8. Colin S, Fanchon M, Belloy L, Bochem AE, Copin C, Derudas B, Stroes ES, Hovingh GK, Kuivenhoven JA, Dallinga-Thie GM, Staels B, Chinetti-Gbaguidi G
HDL does not influence the polarization of human monocytes toward an alternative phenotype.
Int J Cardiol. 2014 Mar 1;172(1):179-84. doi: 10.1016/j.ijcard.2013.12.168. Epub 2014 Jan 8., [PMID:24456889]

Abstract [show]
BACKGROUND: Macrophages are crucial cells in the pathogenesis of atherosclerosis. Macrophages are plastic cells which can switch from a classical pro-inflammatory M1 to an alternative anti-inflammatory M2 macrophage phenotype, depending on the environmental stimuli. Because high-density lipoprotein (HDL) cholesterol levels are inversely correlated to cardiovascular disease and since HDL displays anti-inflammatory properties, we investigated whether HDL can affect alternative macrophage differentiation of primary human monocytes in the presence of interleukin (IL)-4, a M2 macrophage polarization driver, in vitro and ex vivo. METHODS AND RESULTS: M2 macrophages are highly responsive to HDL stimulation, since the expression of pentraxin 3 (PTX3), a well known HDL target gene, is induced by HDL more strongly in M2 macrophages than in control unpolarized resting macrophages (RM). As expected, the expression of M2 markers, such as Mannose Receptor (MR), CD200 Receptor (CD200R), Coagulation factor XIII A1 (F13A1), IL-1 receptor antagonist (IL-1RA) and IL10, was induced in IL-4 polarized M2 macrophages compared to RM. However, incubation with HDL added in vitro did not modulate the gene expression of M2 macrophage polarization markers. Moreover, monocytes isolated from subjects with genetically low HDL levels, carrying ABCA1 or LCAT mutations, differentiated ex vivo into M2 macrophages without any difference in the alternative macrophage marker expression profile. CONCLUSIONS: These in vitro and ex vivo results indicate that, contrary to mouse macrophages, HDL does not influence macrophage M2 polarization of human monocyte-derived macrophages. Thus, the anti-inflammatory properties of HDL in humans are probably not related to the enhancement of the M2 macrophage phenotype.

Comments [show]

None has been submitted yet.

Sentences [show]
No. Sentence Comment
39 We included 6 subjects who carried heterozygous mutations in ABCA1: p.Arg587Trp, p.Val618Asp, p.Ser140Ter, p.Pro85Leu, p.Cys1941Arg/c.6402 + 2TNG, 3 subjects with a homozygous mutation in LCAT: p.Thr147Leu/p.Val333Met, p.Thr147Leu and 3 subjects with a heterozygous mutation in LCAT: p.Pro34Gln [19,20]. Login to comment

[hide] Genes associated with low serum high-density lipop... Arch Iran Med. 2014 Jun;17(6):444-50. doi: 014176/AIM.0013. Ahmadzadeh A, Azizi F
Genes associated with low serum high-density lipoprotein cholesterol.
Arch Iran Med. 2014 Jun;17(6):444-50. doi: 014176/AIM.0013., [PMID:24916532]

Abstract [show]
Atherosclerosis is the main cause of death in the world through causing ischemic heart disease (IHD). Altered serum lipid level is the most important risk factor for coronary artery disease (CAD). Many studies reveal a strong inverse association between low levels of high density lipoprotein cholesterol (HDL-C) and increased risk of IHD. On the other hand, plasma levels of HDL-C has a strong hereditary basis. This review focuses on recent data about genetic defects that reduce the level of HDL-C. In order to investigate possible genes linked to low HDL-C disorder, we reviewed previous studies; we searched current medical literature from September 1990 through January 2013 for the genetics causes of low HDL-C levels. Genetic defects in ATP binding cassette protein (ABCA1), apolipoprotein (APO) A1, lecithin cholesteryl acyl transferase, Lipoprotein lipase (LPL), and angiopoietin-like 3 proteins (ANGPTL3) associated with low HDL-C. Other potentially important candidates involved in low HDL-C syndromes are metabolic disorders including sphingomyelin phosphodiesterase 1 and glucocerebrosidase. Also Molecular variations in many genes such as ABCAI and APOAI, TRIB1 and Apo E, lipoprotein lipase (LPL), WW domain-containing oxidoreductase (WWOX), Hepatic lipase (HL), lecithin cholesteryl acyl transferase and some linkage analysis have been associated with reduced HDL-Status. Low HDL-C syndrome has a strong genetic basis and is correlated with an increased risk of CAD.

Comments [show]

None has been submitted yet.

Sentences [show]
No. Sentence Comment
26 Homozygosity and heterozygosity mutations in this gene have been associated with Tangier disease, an autosomal-recessive disorder characterized by deposition of cholesterol esters in organs, and familial high-density lipoprotein GH&#bf;FLHQF\UHVSHFWLYHO\28,29 /RZFHOOXODUFKROHVWHUROHI&#c0;X[GXHWR mutant ABCA1 leads to reduced apolipoprotein A-I stability and rapid catabolism of HDL-C.30 Over 90 structural variants have been known to cause low HDL-C, most of which are in coding areas, whereas only a few are located in intronic regions31,32 ; e.g., a single defective allele in exon 4 ABCA1 at C254T changing a proline to a leucine (P85L) may be associated with low HDL-C.33 Lecithin cholesteryl acyl transferase LCAT (16q22.1), a member of the lipase superfamily, is a plasma enzyme synthesized by the liver and the small intestine. Login to comment