Deciphering the role of V200A and N291S mutations leading to LPL deficiency.
Familial hypertrygliceridemia
Lipase deficiency
Lipoprotein lipase
Missense and frameshift mutations
cs941507
rs268
rs528243561
rs767260655
Journal
Atherosclerosis
ISSN: 1879-1484
Titre abrégé: Atherosclerosis
Pays: Ireland
ID NLM: 0242543
Informations de publication
Date de publication:
03 2019
03 2019
Historique:
received:
11
10
2018
revised:
19
12
2018
accepted:
09
01
2019
pubmed:
28
1
2019
medline:
12
5
2020
entrez:
28
1
2019
Statut:
ppublish
Résumé
Type I hyperlipoproteinemia is an autosomal recessive disorder of lipoprotein metabolism caused by mutations in the LPL gene, with an estimated prevalence in the general population of 1 in a million. In this work, we studied the molecular mechanism of two known mutations in the LPL gene in ex vivo and in vitro experiments and also the effect of two splice site mutations in ex vivo experiments. Two patients with hypertriglyceridemia were selected from the Lipid Clinic in Vienna. The first patient was compound heterozygote for c.680T > C (exon 5; p.V200A) and c.1139+1G > A (intron 7 splice site). The second patient was compound heterozygote for c.953A > G (exon 6; p.N291S) and c.1019-3C > A (intron 6 splice site). The LPL gene was sequenced and post-heparin plasma samples (ex vivo) were used to test LPL activity. In vitro experiments were performed in HEK 293T/17 cells transiently transfected with wild type or mutant LPL plasmids. Cell lysate and media were used to evaluate LPL production, secretion, activity and dimerization by Western blot analysis and LPL enzymatic assay, respectively. Our data show that in both patients, LPL activity is absent. V200A is a mutation that alters LPL secretion and activity whereas the N291S mutation affects LPL activity, but both mutations do not affect dimerization. The effect of these mutations in patients is more severe since they have splice site mutations on the other allele. We characterized these LPL mutations at the molecular level showing that are pathogenic.
Sections du résumé
BACKGROUND AND AIMS
Type I hyperlipoproteinemia is an autosomal recessive disorder of lipoprotein metabolism caused by mutations in the LPL gene, with an estimated prevalence in the general population of 1 in a million. In this work, we studied the molecular mechanism of two known mutations in the LPL gene in ex vivo and in vitro experiments and also the effect of two splice site mutations in ex vivo experiments.
METHODS
Two patients with hypertriglyceridemia were selected from the Lipid Clinic in Vienna. The first patient was compound heterozygote for c.680T > C (exon 5; p.V200A) and c.1139+1G > A (intron 7 splice site). The second patient was compound heterozygote for c.953A > G (exon 6; p.N291S) and c.1019-3C > A (intron 6 splice site). The LPL gene was sequenced and post-heparin plasma samples (ex vivo) were used to test LPL activity. In vitro experiments were performed in HEK 293T/17 cells transiently transfected with wild type or mutant LPL plasmids. Cell lysate and media were used to evaluate LPL production, secretion, activity and dimerization by Western blot analysis and LPL enzymatic assay, respectively.
RESULTS
Our data show that in both patients, LPL activity is absent. V200A is a mutation that alters LPL secretion and activity whereas the N291S mutation affects LPL activity, but both mutations do not affect dimerization. The effect of these mutations in patients is more severe since they have splice site mutations on the other allele.
CONCLUSIONS
We characterized these LPL mutations at the molecular level showing that are pathogenic.
Identifiants
pubmed: 30685441
pii: S0021-9150(19)30010-3
doi: 10.1016/j.atherosclerosis.2019.01.004
pii:
doi:
Substances chimiques
LPL protein, human
EC 3.1.1.34
Lipoprotein Lipase
EC 3.1.1.34
Types de publication
Case Reports
Journal Article
Research Support, Non-U.S. Gov't
Langues
eng
Sous-ensembles de citation
IM
Pagination
45-51Informations de copyright
Copyright © 2019 The Authors. Published by Elsevier B.V. All rights reserved.