Ayşegül Başak AKADAM TEKER, Erhan TEKER, Özlem KURNAZ GÖMLEKSİZ, Hülya YILMAZ AYDOĞAN

Koroner Kalp Hastalarında PCSK9 E670G ve N425S Gen Varyasyonlarının Etkisinin Türk Toplumunda Değerlendirilmesi

Amaç: Aterosklerozdan kaynaklanan Koroner Arter Hastalığı (KAH) çeşitli genetik ve çevresel etmenlerin etkileşiminden kaynaklanan multifaktöriyel bir hastalıktır. Gelişmiş ülkelerde en yüksek mortalite ve morbidite nedenlerindendir. Proprotein subtilisin keksin tip-9 (PCSK9), Düşük Yoğunluklu Lipoprotein Reseptörü (Low-density lipoprotein-Receptor / LDLR)'nün post-transkripsiyonel degredasyonunu indükleyerek kolesterol hemostazında önemli bir rol oynamaktadır. PCSK9'un ilk keşfedildiği 2003 yılından bu yana çalışmalar hız kesmeden devam etmiş ve artık anti-PCSK9 monoklonal antikorları ateroskleroz tedavisinde yeni bir hedef olarak sunulmuştur. Ancak Türk popülasyonunda PCSK9'un genetik varyasyonları ve LDL-kolesterol (LDL-K) üzerindeki etkisi hakkında çok az bilgi vardır. PCSK9 genindeki mutasyonlar sırasıyla fonksiyon kaybı ve fonsiyon kazanımı mekanizmaları aracılığı ile hem hipokolesterolemi hemde hiperkolesterolemi ile ilişkilidir. Çalışmamızda; PCSK9 fonksiyon kazanımı ile ilişkili N425S (rs28362261) ve E670G (23968A>G) (rs 505151) gen polimorfizmlerinin serum lipoprotein düzeyi ve KAH gelişimindeki etkilerinin belirlenmesi amaçlanmıştır. Yöntem: 64 hasta ve 50 kontrol’ün PCSK9 E670G ve N425S varyantının belirlenmesi için PCR-RFLP (Polimeraz Zincir Reaksiyonu-Restriksiyon Parça Uzunluk Polimorfizmi) yöntemi kullanılmıştır. Bulgular: Koroner arter hastalarında PCSK9 E670G mutant T alleli frekansı kontrol grubuna göre daha yüksek gözlenmiştir. Verilerimiz bu varyantın koroner kalp hastalığı gelişiminde bağımsız risk faktörü olabileceğini önermektedir. Koroner arter hastalarında PCSK9 E670G normal A alleli yüksek serum total-kolesterol düzeyi ile ilişkili bulunmuştur. PCSK9 N425S polimorfizmi dağılımlarında hasta ve kontrol gruplarında sadece NN normal homozigot genotipi gözlenmiştir. Sonuç: PCSK9 genindeki E670G varyantının serum lipid profili üzerindeki olumsuz etkileriyle koroner kalp hastalığı gelişiminde risk oluşturabileceğini göstermektedir.

Anahtar Kelimeler:

LDL-K, Proprotein konvertaz subtilisin keksin tip-9 (PCSK9), koroner arter hastalığı, lipoprotein, hiperkolesterolemi

Evaluation of PCSK9 E670G and N425S Gene Variations in Coronary Heart Disease in Turkish Population

Aim: Coronary artery disease (CAD) due to atherosclerosis is a multifactorial disease resulting from the interaction of numerous genetic and environmental factors. In developed countries, it is among the diseases with highest rates of mortality and morbidity. Proprotein convertase subtilisin/kexin 9 (PCSK9), plays an important role for cholesterol homoeostasis via inducing post-transcriptional degradation of Low-density lipoprotein-Receptor (LDLR).Since PCSK9’s first discovery in 2003, studies focusing on PCSK9 continue without slowing down and now PCSK9 is a candidate as a new therapeutic target in atherosclerosis. However, little is known about the genetic variants of PCSK9 and its influence on Low Density Lipoprotein – cholesterol (LDL-C) in Turkish population. Mutations in the PCSK9 gene have been associated with both hypocholesterolemia and hypercholesterolemia through ‘loss-of-function’ and ‘gain-of-function’ mechanisms, respectively. Our aim was to investigate PCSK9 N425S (rs28362261) and E670G (23968A>G) (rs 505151) gene polymorphisms in regard to their effects on serum lipoprotein level and development of CHD.Method: PCR-RFLP (Polymerase Chain Reaction-Restriction Fragment Length Polymorphism) method is used for determination of PCSK9 variants.Findings: In the patient group, frequency of PCSK9 E670G mutant T allele is higher than controls. Our findings indicate that these variants might be an independent risk factors in development of CHD. In the patient group, we observed the PCSK9 E670G normal A allele is associated with increased serum total-cholesterol level. Conclusion: In conclusion we suggest that the PCSK9 gene variants might pose a risk in susceptibility to CHD, since PCSK9 has detrimental effects on serum lipids.

Keywords:

Proprotein convertase subtilisin/kexin-9 (PCSK9), coronary artery disease, lipoprotein, LDL-C, hypercholesterolemia,

PDF

___

Thirumalai T, Tamilselvan N, David E. Hypolipidemic activity of Piper betel in high fat diet induced hyperlipidemic rat. J Acute Disease. 2014;(3):131–135. https://doi.org/10.1016/S2221-6189(14)60029-9.
Abifadel M, Varret M, Rabès JP, et al. Mutations in PCSK9 cause autosomal dominant hypercholesterolemia. Nat Genet. 2003;34(2):154–156. doi: 10.1038/ng1161.
Lalanne F, Lambert G, Amar MJ, et al. Wild-type PCSK9 inhibits LDL clearance but does not affect apo B-containing lipoprotein production in mouse and cultured cells. J Lipid Res. 2005;46(6):1312-1319. doi: 10.1194/jlr.M400396-JLR200.
Park SW, Moon YA, Horton JD. Post-transcriptional regulation of low-density lipoprotein receptor protein by proprotein convertase subtilisin/ kexin type 9a in mouse liver. J Biol Chem. 2004;279(48):50630–50638. doi: 10.1074/jbc.M410077200.
Seidah NG, Benjannet S, Wickham L, et al. The secretory proprotein convertase neural apoptosis-regulated convertase 1 (NARC-1): Liver regeneration and neuronal differentiation. Proc Natl Acad Sci USA. 2003;100(3):928-933. doi: 10.1073/pnas.0335507100.
Dubuc G, Chamberland A, Wassef H, et al. Statins upregulate PCSK9, the gene encoding the proprotein convertase neural apoptosis-regulated convertase-1 implicated in familial hypercholesterolemia. Arterioscler Thromb Vasc Biol. 2004;24(8):1454-1459. doi: 10.1161/01.ATV.0000134621.14315.43.
Maxwell KN, Fisher EA, Breslow JL. Overexpression of PCSK9 accelerates the degradation of the LDLR in a post-endoplasmic reticulum compartment. Proc Natl Acad Sci USA. 2005;102(6):2069–2074. doi: 10.1073/pnas.0409736102.
Benjannet S, Rhainds D, Essalmani R, et al. NARC-1/PCSK9 and its natural mutants: Zymogen cleavage and effects on the low-density lipoprotein (LDL) receptor and LDL cholesterol. J Biol Chem. 2004;279(47):48865-48875. doi: 10.1074/jbc.M409699200.
Maxwell KN, Breslow JL. Adenoviral-mediated expression of PCSK9 in mice results in a low-density lipoprotein receptor knockout phenotype. Proc Natl Acad Sci USA. 2004;101(18):7100-7115. doi: 10.1073/pnas.0402133101.
Horton JD, Shah NA, Warrington JA, et al. Combined analysis of oligonucleotide microarray data from transgenic and knockout mice identifies direct SREBP target genes. Proc Natl Acad Sci USA. 2003;100(21):12027-12032. doi: 10.1073/pnas.1534923100.
Leren, TP. Mutations in the PCSK9 gene in Norwegian subjects with autosomal dominant hypercholesterolemia. Clin Genet. 2004;65(5):419–422. doi: 10.1111/j.0009-9163.2004.0238.x.
Sun XM, Eden ER, Tosi I, et al. Evidence for effect of mutant PCSK9 on apolipoprotein B secretion as the cause of unusually severe dominant hypercholesterolaemia. Hum Mol Genet. 2005;14(9):1161–1169. doi: 10.1093/hmg/ddi128.
Timms KM, Wagner S, Samuels ME, et al. A mutation in PCSK9 causing autosomal-dominant hypercholesterolemia in a Utah pedigree. Hum Genet. 2004;114(4):349–353. doi: 10.1007/s00439-003-1071-9.
Zhao ZY, Tuakli-Wosornu TA, Lagace L, et al. Molecular characterization of loss-of-function mutations in PCSK9 and identification of a compound heterozygote. Am J Hum Genet. 2006;79(3):514–523. doi: 10.1086/507488.
Cohen J, Pertsemlidis A, Kotowski IK, et al. Low LDL cholesterol in individuals of African descent resulting from frequent nonsense mutations in PCSK9. Nat Genet. 2005;37(2):161–165. doi: 10.1038/ng1509.
Welder G, Zineh I, Pacanowski MA, et al. High-dose atorvastatin causes a rapid sustained increase in human serum PCSK9 and disrupts its correlation with LDL cholesterol. J Lipid Res. 2010;51(9):2714-2721. doi: 10.1194/jlr.M008144.
Evans D, Beil FU. The E670G SNP in the PCSK9 gene is associated with polygenic hypercholesterolemia in men but not in women. BMC Med Genet. 2006;(31):7-66. https://doi.org/10.1186/1471-2350-7-66.
Pisciotta L, Priore Oliva C, Cefalù AB, et al. Additive effect of mutations in LDLR and PCSK9 genes on the phenotype of familial hypercholesterolemia. Atherosclerosis. 2006;186(2):433-440. doi: 10.1016/j.atherosclerosis.2005.08.015.
Hampton EN, Knuth MW, Li J, et al. The self-inhibited structure of full-length PCSK9 at 1.9 A reveals structural homology with resistin within the C-terminal domain. Proc Natl Acad Sci USA. 2007;104(37):14604-14609. doi: 10.1073/pnas.0703402104.
Zhang DW, Lagace TA, Garuti R, et al. Binding of proprotein convertase subtilisin/kexin type 9 to epidermal growth factor-like repeat A of low density lipoprotein receptor decreases receptor recycling and increases degradation. J Biol Chem. 2007;282(25):18602-18612. doi: 10.1074/jbc.M702027200.
Fasano T, Sun XM, Patel DD, Soutar AK. Degradation of LDLR protein mediated by ‘Gain of function’ PCSK9 mutants in normal and ARH cells. Atherosclerosis. 2009;203(1):166–171. doi: 10.1016/j.atherosclerosis. 2008.10.027.
Chen SN, Ballantyne CM, Gotto AM Jr, et al. A common PCSK9 haplotype, encompassing the E670G coding single nucleotide polymorphism, is a novel genetic marker for plasma low-density lipoprotein cholesterol levels and severity of coronary atherosclerosis. J Am Coll Cardiol. 2005;45(10):1611-1619. doi: 10.1016/j.jacc.2005.01.051.
Abboud S, Karhunen PJ, Lütjohann D, et al. Proprotein convertase subtilisin/kexin type 9 (PCSK9) gene is a risk factor of large-vessel atherosclerosis stroke. PLoS ONE. 2007;2(10):e1043. https://doi.org/10.1371/journal.pone.0001043.