Association of the Genetic Polymorphisms in Pre-MicroRNAs with Risk of Ischemic Stroke in a Chinese Population

February Association of the Genetic Polymorphisms in Pre-MicroRNAs with Risk of Ischemic Stroke in a Chinese Population Suli Huang 0 1 2 Shiquan Zhou 0 1 2 Yanwei Zhang 0 1 2 Ziquan Lv 0 1 2 Shanshan Li 0 1 2 Changhui Xie 0 1 2 Yuebin Ke 0 1 2 Pingjian Deng 0 1 2 Yijie Geng 0 1 2 Qian Zhang 0 1 2 Xiaofan Chu 0 1 2 Zhaohui Yi 0 1 2 Ying Zhang 0 1 2 Tangchun Wu 0 1 2 Jinquan Cheng 0 1 2 0 1 Key Laboratory of Molecular Biology, Shenzhen Center for Disease Control and Prevention , Shenzhen , China , 2 LongHua new District Center for Disease Control and Prevention , Shenzhen , China , 3 Department of Neurology, People's Hospital of Shenzhen , Shenzhen , China , 4 Key Laboratory of Environment and Health, Ministry of Education & Ministry of Environmental Protection, and State Key Laboratory of Environmental Health (Incubating), School of Public Health, Tongji Medical College, Huazhong University of Science and Technology , Wuhan, Hubei , China 1 Funding: This work was supported by the following sources: National Natural Science Foundation of China (no: 30771852, JQC), for study design, China Postdoctoral Scientific Foundation (no:2014M562031, SLH) for data collection and analysis, and National Natural Science Foundation of China (no: 81402754, SLH) for preparation of the manuscript 2 Academic Editor: Xin-Yuan Guan, The University of Hong Kong , CHINA microRNA (miRNA) plays a role in the pathogenesis of ischemic stroke, and single nucleotide polymorphisms in miRNA genes may contribute to disease susceptibility. However, the effect of miR-146a, miR-196a2, and miR-499 polymorphisms on ischemic stroke susceptibility has been rarely reported. Using the TaqMan assay, we evaluated the association of hsa-miR-146a/rs2910164, hsa-miR-196a2/rs11614913, and hsa-miR-499/rs3746444 polymorphisms with the risk of ischemic stroke in a Chinese population with 531 ischemic stroke patients and 531 control subjects. Rs2910164 C/G genotypes were significantly associated with increased risk of ischemic stroke in different genetic model (homozygote comparison: OR = 2.00, 95% CI, 1.29-3.12, P = 0.002; additive model: OR = 1.35, 95% CI, 1.10-1.65, P = 0.004;dominant model: OR = 1.33, 95% CI, 1.00-1.75, P = 0.049; recessive model: OR = 1.82, 95% CI, 1.20-2.74, P = 0.004). Subjects with allele G of hsa-miR-146a/ rs2910164 also showed increased risk of ischemic stroke (OR = 1.33, 95% CI, 1.09-1.62, P = 0.005). Stratification analysis showed that the association between rs2910164 and the risk of ischemic stroke was more pronounced in subjects over 60 years old, females, non-drinkers, subjects without hypertension or diabetes mellitus. There were significant combined effects between miR-146a/rs2910164 and fasting glucose/low-density lipoprotein cholesterol levels on ischemic stroke susceptibility. However, we failed to find any association between the alleles/genotypes of rs11614913 T/C and ischemic stroke, respectively (P> 0.05). In summary, this study provides evidence that miR-146a/rs2910164 might be associated with a significantly increased risk of ischemic stroke in a Chinese population, and the combined effects between miRNA polymorphism and fasting glucose /blood lipid levels may contribute to stroke pathogenesis. - Competing Interests: The authors have declared that no competing interests exist. Globally, stroke is the second leading cause of death for people over 60 years old [1]. In China, with 1.4 billion populations, the annual stroke mortality rate is approximately 157 per 100000, which has exceeded heart disease and become the leading cause of death and adult disability [2]. About 80% of strokes are ischemic in origin [3]. Ischemic stroke is a complex disease caused by multiple genetic and environmental factors. In addition to the conventional risk factors, such as age, sex, body mass index, hypertension, diabetes mellitus, smoking, and hyperlipidemia, single-nucleotide polymorphisms (SNPs) have been identified in genome-wide association studies (GWAS) as susceptibility loci for ischemic stroke risk [4,5]. However, such loci explain only a small portion of the total risk, and few of these SNPs discovered by GWAS involve miRNA genes. microRNAs (miRNAs) are a class of *22-nucleotide non-protein coding RNAs that have emerged as key regulators of fundamental biological processes through regulating more than one third of human genes by binding to the 3untranslated region of target gene mRNAs [6]. miRNAs are initially transcribed as primary miRNAs (pri-miRNA) with several hundred nucleotides, which are further processed into hairpin-structured precursor miRNAs (premiRNA) that have approximately 70 nucleotides. Pre-miRNAs are the direct precursors of mature miRNAs that have 18 to 25 nucleotides in length [7,8]. Emerging evidence supports a role of miRNAs in regulating a variety of ischemic stroke-related biologic processes, such as atherosclerosis, hypertension and plaque rupture et al [9]. miRNAs are also aberrantly expressed in ischemic stroke, and specific miRNAs have been shown to be associated with the clinical subtype of stroke and could be used as biomarker for ischemic stroke [10]. Recently, it has been proposed that the presence of genetic variants in miRNA genes could affect the processing and subsequent maturation of miRNAs [11], and collectively affect the risk and/or prognosis of diseases. Three well-known miRNA polymorphisms in pre-miRNA sequences (miR-146a C>G, rs2910164; miR-196a2 T>C, rs11614913; and miR-499 A>G, rs3746444) have been extensively studied and were found to be associated with the risk and/or prognosis of various diseases [12,13]. Interestingly, the three miRNAs also regulate genes related to thrombosis and inflammation pathways in the circulation system, including tumor necrosis factor- (TNF-) [14], annexin A1 (ANXA1) [15], and C-reactive protein (CRP) [16], and affect vascular damage response. However, rare data has been reported regarding the role of the miRNA polymorphisms in the pathogenesis of ischemic stroke. In this study, we sought to investigate the association between the three miRNA polymorphisms and ischemic stroke risk in a Chinese population. Materials and Methods Study population This study is a hospital-based case-control study including 531 patients with ischemic stroke and 531 healthy unrelated volunteers. All subjects were the ethnic Han origin by self-description and unrelated Chinese people. All cases were first-diagnosed with ischemic stroke and recruited from ischemic stroke inpatients in the Department of Neurology, People's Hospital of Shenzhen (Guangdong, China) from July 2012 to July 2013. The diagnosis of ischemic stroke was based on the appearance of a new and abrupt focal neurological deficit, with neurological symptoms and signs persisting for more than 24h. Ischemic stroke was confirmed by the positive findings by head CT or MRI according to the International Classification of Disease (9th Revision, codes 430 to 438). Patients (...truncated)