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The Arg499His gain-of-function mutation in the C-terminal domain of PCSK9
- Source :
- Atherosclerosis. 289:162-172
- Publication Year :
- 2019
- Publisher :
- Elsevier BV, 2019.
-
Abstract
- Background and aims Familial hypercholesterolemia (FH) is a monogenic disease characterized by high levels of low-density lipoprotein cholesterol and premature atherosclerotic cardiovascular disease. FH is caused by loss of function mutations in genes encoding LDL receptor (LDLR), and Apolipoprotein B (APOB) or gain of function (GOF) mutations in proprotein convertase subtilisin/kexin type 9 (PCSK9). In this study, we identified a novel variant in PCSK9, p.(Arg499His), located in the C-terminal domain, in two unrelated FH patients from Spain and Italy. Methods We studied familial segregation and determined variant activity in vitro. Results We determined PCSK9 expression, secretion and activity of the variant in transfected HEK293 cells; extracellular activity of the recombinant p.(Arg499His) PCSK9 variant in HEK 293 and HepG2 cells; PCSK9 affinity to the LDL receptor at neutral and acidic pH; the mechanism of action of the p.(Arg499His) PCSK9 variant by co-transfection with a soluble construct of the LDL receptor and by determining total PCSK9 intracellular accumulation when endosomal acidification is impaired and when an excess of soluble LDLr is present in the culture medium. Our results show high LDL-C concentrations and FH phenotype in p.(Arg499His) carriers. In vitro functional characterization shows that p.(Arg499His) PCSK9 variant causes a reduction in LDLr expression and LDL uptake. An intracellular activity for this variant is also shown when blocking the activity of secreted PCSK9 and by inhibiting endosomal acidification. Conclusions We demonstrated that p.(Arg499His) PCSK9 variant causes a direct intracellular degradation of LDLr therefore causing FH by reducing LDLr availability.
- Subjects :
- 0301 basic medicine
Heterozygote
Apolipoprotein B
Familial hypercholesterolemia
030204 cardiovascular system & hematology
Arginine
03 medical and health sciences
chemistry.chemical_compound
0302 clinical medicine
Protein Domains
Genetic
medicine
Humans
Histidine
Dyslipemia
Functional assay
Child
Family Health
biology
Cholesterol
PCSK9
Cell Membrane
HEK 293 cells
Hep G2 Cells
Middle Aged
Lipid
medicine.disease
Proprotein convertase
Molecular biology
Culture Media
Pedigree
HEK293 Cells
030104 developmental biology
Italy
Receptors, LDL
chemistry
Spain
Gain of Function Mutation
LDL receptor
biology.protein
Kexin
Female
lipids (amino acids, peptides, and proteins)
Gene expression
Proprotein Convertase 9
Cardiology and Cardiovascular Medicine
Mutations
Subjects
Details
- ISSN :
- 00219150
- Volume :
- 289
- Database :
- OpenAIRE
- Journal :
- Atherosclerosis
- Accession number :
- edsair.doi.dedup.....2924aa95b188a118450a82c378a2c6c8