Institute of Life Sciences, Nalco Square, Chandrasekharpur, Bhubaneswar, India.
Laboratory of Molecular and Cellular Screening Processes, Centre of Biotechnology of Sfax, University of Sfax, Sfax, Tunisia.
PLoS One. 2022 Jun 3;17(6):e0269558. doi: 10.1371/journal.pone.0269558. eCollection 2022.
Otosclerosis (OTSC) is the primary form of conductive hearing loss characterized by abnormal bone remodelling within the otic capsule of the human middle ear. A genetic association of the RELN SNP rs3914132 with OTSC has been identified in European population. Previously, we showed a trend towards association of this polymorphism with OTSC and identified a rare variant rs74503667 in a familial case. Here, we genotyped these variants in an Indian cohort composed of 254 OTSC cases and 262 controls. We detected a significant association of rs3914132 with OTSC (OR = 0.569, 95%CI = 0.386-0.838, p = 0.0041). To confirm this finding, we completed a meta-analysis which revealed a significant association of the rs3914132 polymorphism with OTSC (Z = 6.707, p<0.0001) across different ethnic populations. Linkage analysis found the evidence of linkage at RELN locus (LOD score 2.1059) in the OTSC family which has shown the transmission of rare variant rs74503667 in the affected individuals. To understand the role of RELN and its receptors in the development of OTSC, we went further to perform a functional analysis of RELN/reelin. Here we detected a reduced RELN (p = 0.0068) and VLDLR (p = 0.0348) mRNA levels in the otosclerotic stapes tissues. Furthermore, a reduced reelin protein expression by immunohistochemistry was confirmed in the otosclerotic tissues. Electrophoretic mobility shift assays for rs3914132 and rs74503667 variants revealed an altered binding of transcription factors in the mutated sequences which indicates the regulatory role of these variations in the RELN gene regulation. Subsequently, we showed by scanning electron microscopy a change in stapes bone morphology of otosclerotic patients. In conclusion, this study evidenced that the rare variation rs74503667 and the common polymorphism rs3914132 in the RELN gene and its reduced expressions that were associated with OTSC.
耳硬化症（otosclerosis，OTSC）是一种以人类中耳骨迷路异常重塑为特征的传导性听力损失的主要形式。RELN 基因 rs3914132 单核苷酸多态性与 OTSC 的遗传关联已在欧洲人群中得到鉴定。先前，我们发现该多态性与 OTSC 呈趋势相关，并在一个家族病例中鉴定出一种罕见变异 rs74503667。在此，我们对由 254 例 OTSC 患者和 262 例对照组成的印度队列进行了这些变体的基因分型。我们检测到 rs3914132 与 OTSC 显著相关（OR = 0.569，95%CI = 0.386-0.838，p = 0.0041）。为了证实这一发现，我们完成了一项荟萃分析，结果表明 rs3914132 多态性与 OTSC 显著相关（Z = 6.707，p<0.0001），这一关联存在于不同种族人群中。连锁分析在 OTSC 家族中发现了 RELN 基因座的连锁证据（LOD 得分 2.1059），该家族中 rs74503667 罕见变异在受影响个体中发生了传递。为了了解 RELN 及其受体在 OTSC 发展中的作用，我们进一步对 RELN/reelin 进行了功能分析。在此，我们检测到硬化镫骨组织中 RELN（p = 0.0068）和 VLDLR（p = 0.0348）mRNA 水平降低。此外，通过免疫组织化学进一步证实了硬化组织中 reelin 蛋白表达减少。对 rs3914132 和 rs74503667 变体的电泳迁移率变动分析显示，突变序列中转录因子的结合发生改变，这表明这些变异在 RELN 基因调控中具有调节作用。随后，我们通过扫描电子显微镜观察到硬化患者镫骨骨形态的变化。总之，这项研究证明了 RELN 基因中的罕见变异 rs74503667 和常见多态性 rs3914132 及其与 OTSC 相关的表达降低。
