A genome-wide expression quantitative trait loci analysis of proprotein convertase subtilisin/kexin enzymes identifies a novel regulatory gene variant for FURIN expression and blood pressure
HUMAN GENETICS
Authors: Turpeinen, Hannu; Seppala, Ilkka; Lyytikainen, Leo-Pekka; Raitoharju, Emma; Hutri-Kahonen, Nina; Levula, Mari; Oksala, Niku; Waldenberger, Melanie; Klopp, Norman; Illig, Thomas; Mononen, Nina; Laaksonen, Reijo; Raitakari, Olli; Kahonen, Mika; Lehtimaki, Terho; Pesu, Marko
Abstract
Proprotein convertase subtilisin/kexin (PCSK) enzymes cleave and convert their immature substrates into biologically active forms. Polymorphisms in the PCSK genes have been reported to associate with human diseases and phenotypes, including hypercholesterolemia and blood pressure (BP), and targeting PCSKs is considered a promising future form of drug therapy. PCSK processing is readily induced upon upregulation of the enzyme, but the genetic factors contributing to PCSK expression have not been thoroughly characterized. To gain a comprehensive understanding of the genetic regulation of PCSK expression, we performed, for the first time, a genome-wide expression quantitative trait loci (eQTL) analysis using mRNA expression in > 1400 human peripheral blood samples from the Cardiovascular Risk in Young Finns Study and ca. ten million single-nucleotide polymorphisms (SNPs). The expression data showed clear expression for FURIN, PCSK5, PCSK7 and MBTPS1 (membrane-bound transcription factor peptidase, site 1) mRNAs in virtually all tested samples. A discovery analysis demonstrated a genome-wide significant (p < 5 x 10(-8)) association with the selected PCSK probes for 1024 variants, which were located at ten independent loci. Of these loci, 5/10 could be confirmed to regulate PCSK expression in two additional and independent sample sets. Finally, a phenotypic analysis demonstrated that a novel cis-eQTL SNP rs4702 for FURIN is strongly associated with both diastolic (p = 0.012) and systolic (p = 0.035) BP levels, as well as peripheral vascular resistance (p = 0.003). These findings indicate that the expression of the PCSK enzymes is regulated by genetic factors, which have biological roles in health and disease.
Intake levels of dietary polyunsaturated fatty acids modify the association between the genetic variation in PCSK5 and HDL cholesterol
JOURNAL OF MEDICAL GENETICS
Authors: Jang, Han Byul; Hwang, Joo-Yeon; Park, Ji Eun; Oh, Ji Hee; Ahn, YounJhin; Kang, Jae-Heon; Park, Kyung-Hee; Han, Bok-Ghee; Kim, Bong Jo; Park, Sang Ick; Lee, Hye-Ja
Abstract
Background A low serum level of high-density lipoprotein cholesterol (HDL-C) is a risk factor for cardiovascular disease. Proprotein convertase subtilisin/kexin type 5 (PCSK5) modulates HDL-C metabolism through the inactivation of endothelial lipase activity. Methods Therefore, we analysed the effects of PCSK5 on HDL-C and investigated the association between genetic variation in PCSK5 and dietary polyunsaturated fatty acids (PUFAs) intakes in Korean adults and children. This population-based study which was conducted in South Korea included 4205 adults (43% male) aged 40-69 years and 1548 children (48.6% boys) aged 8-13 years. Dietary intake was assessed using a semiquantitative food frequency questionnaire in adults and modified 3-day food records in children. Results After adjustments for age and body mass index, we identified a significant association between SNP rs1029035 of the PCSK5 gene and HDL-C concentrations specifically for men in both populations (adults, p=0.004; children, p=0.003; meta, p=7x10(-4)). Additionally, the interaction between the PCSK5 rs1029035 genotype and dietary polyunsaturated fatty acids intake influenced serum HDL-C concentrations in men (adults, p=0.001; children, p=0.008). The deleterious effect of the C allele on serum HDL-C was present only when dietary PUFA intake was less than the dichotomised median level (adults, p=0.011; children, p=0.001). Serum HDL-C concentrations were decreased in men with the C allele genotype and low consumption of dietary PUFA including n-3 and n-6. Conclusion According to these results, men carrying of the C allele were associated with low HDL-C concentrations and might exert beneficial effects on HDL-C concentrations following consumption of a high-PUFA diet.