Cheishvili David, Dietrich Paula, Maayan Channa, Even Aviel, Weil Miguel, Dragatsis Ioannis, Razin Aharon
Familial Dysautonomia Centre, Pediatric Department Hadassah Hospital Hebrew University Hadassah Medical School, Jerusalem, Israel; Department of Developmental Biology and Cancer Research, Institute of Medical Research Israel-Canada, The Hebrew University Hadassah Medical School, Jerusalem, Israel.
Department of Physiology, College of Medicine, The University of Tennessee, Health Science Center, Memphis, Tennessee, United States of America.
PLoS One. 2014 Apr 23;9(4):e94612. doi: 10.1371/journal.pone.0094612. eCollection 2014.
The splice site mutation in the IKBKAP gene coding for IKAP protein leads to the tissue-specific skipping of exon 20, with concomitant reduction in IKAP protein production. This causes the neurodevelopmental, autosomal-recessive genetic disorder - Familial Dysautonomia (FD). The molecular hallmark of FD is the severe reduction of IKAP protein in the nervous system that is believed to be the main reason for the devastating symptoms of this disease. Our recent studies showed that in the brain of two FD patients, genes linked to oligodendrocyte differentiation and/or myelin formation are significantly downregulated, implicating IKAP in the process of myelination. However, due to the scarcity of FD patient tissues, these results awaited further validation in other models. Recently, two FD mouse models that faithfully recapitulate FD were generated, with two types of mutations resulting in severely low levels of IKAP expression. Here we demonstrate that IKAP deficiency in these FD mouse models affects a similar set of genes as in FD patients' brains. In addition, we identified two new IKAP target genes involved in oligodendrocyte cells differentiation and myelination, further underscoring the essential role of IKAP in this process. We also provide proof that IKAP expression is needed cell-autonomously for the regulation of expression of genes involved in myelin formation since knockdown of IKAP in the Oli-neu oligodendrocyte precursor cell line results in similar deficiencies. Further analyses of these two experimental models will compensate for the lack of human postmortem tissues and will advance our understanding of the role of IKAP in myelination and the disease pathology.
编码IKAP蛋白的IKBKAP基因中的剪接位点突变导致外显子20的组织特异性跳跃,同时IKAP蛋白产生减少。这会引发神经发育性常染色体隐性遗传病——家族性自主神经功能异常(FD)。FD的分子标志是神经系统中IKAP蛋白的严重减少,这被认为是该疾病出现毁灭性症状的主要原因。我们最近的研究表明,在两名FD患者的大脑中,与少突胶质细胞分化和/或髓鞘形成相关的基因显著下调,这表明IKAP参与了髓鞘形成过程。然而,由于FD患者组织稀缺,这些结果有待在其他模型中进一步验证。最近,生成了两种忠实地模拟FD的FD小鼠模型,两种类型的突变导致IKAP表达水平极低。在这里,我们证明这些FD小鼠模型中的IKAP缺陷影响了与FD患者大脑中相似的一组基因。此外,我们鉴定出两个参与少突胶质细胞分化和髓鞘形成的新的IKAP靶基因,进一步强调了IKAP在此过程中的重要作用。我们还提供了证据,证明IKAP表达对于髓鞘形成相关基因的表达调控是细胞自主必需的,因为在Oli-neu少突胶质细胞前体细胞系中敲低IKAP会导致类似的缺陷。对这两种实验模型的进一步分析将弥补人类尸检组织的不足,并推动我们对IKAP在髓鞘形成和疾病病理中的作用的理解。