H/ACA Box Small Nucleolar RNA 7A Promotes the Self-Renewal of Human Umbilical Cord Mesenchymal Stem Cells
H/ACA Box Small Nucleolar RNA 7A Promotes the Self-Renewal of Human Umbilical Cord Mesenchymal Stem Cells
复制标题
H/ACA Box小核仁RNA 7A促进人脐带间充质干细胞的自我更新
作者：
Zhang Yan;Xu Chen;Gu Daolan;Wu Minjuan;Yan Binghao;Xu Zhenyu;Wang Yue;Liu Houqi
人脐带血间充质干细胞（uMSC）是一种多能性细胞，目前已被认为是多种细胞治疗的理想候选细胞。然而，它们有限的体外增殖能力和多能性的逐渐丧失为进一步的应用设置了障碍。新出现的证据表明，小核仁RNA（snoRNA）积极参与细胞增殖，特别是在肿瘤细胞中，但它们在干细胞中的作用在很大程度上是未知的。在这项研究中，我们证明了H/ACA盒小核仁RNA 7A（SNORA 7A）与uMSC体外传代过程中增殖率的降低呈负相关。进一步的研究表明，SNORA 7A过表达可以促进uMSC增殖和自我更新。使用反义寡核苷酸抑制SNORA 7A显著降低了SNORA 7A与DKC 1的表达和结合，DKC 1是形成小核仁核糖核颗粒（snoRNP）复合物和催化28 S RNA中的假尿苷所必需的核心蛋白。抑制uMSC的增殖和自我更新。此外，与snoRNP核心蛋白和28 S RNA的结合区域的突变的SNORA 7A转录本的过表达不诱导增殖和自我更新。此外，SNORA 7A还抑制uMSC的成骨和成脂分化，加强其自我更新维持作用。综上所述，我们的研究首次表明，H/ACA盒snoRNA积极参与MSC增殖以及多能性控制，并且我们将SNORA 7A鉴定为通过snoRNP募集调节uMSC增殖和自我更新的关键snoRNA之一。
AbstractHuman umbilical cord blood derived mesenchymal stem cells (uMSC) are pluripotent cells that have been now considered as a promising candidate for various cell-based therapies. However, their limited in vitro proliferation ability and the gradual loss of pluripotency set barricades for further usages. Emerging evidence suggests that small nucleolar RNAs (snoRNA) are actively involved in cell proliferation especially in tumor cells, but their roles in stem cells are largely unknown. In this study, we demonstrated that H/ACA box small nucleolar RNA 7A (SNORA7A) is inversely correlated to the decreased proliferation rate during in vitro passaging of uMSC. Further investigations indicate that SNORA7A overexpression can promote uMSC proliferation and self-renewal. The inhibition of SNORA7A using antisense oligonucleotides significantly reduces the expression and the binding of SNORA7A to DKC1, core protein that essential to form small nucleolar ribonucleo-particles (snoRNP) complex and catalyze pseudouridines in 28S RNA. And the inhibition also significantly suppresses uMSC proliferation and self-renewal. Moreover, overexpression of SNORA7A transcripts with mutations of binding regions for snoRNP core proteins and 28S RNA did not induce proliferation and self-renewal. Besides, SNORA7A also suppresses both the osteogenic and adipogenic differentiation, strengthening its self-renewal maintaining roles in uMSC. Taken together, our study for the first time showed that H/ACA box snoRNAs are actively involved in MSC proliferation as well as pluripotency control, and we identify SNORA7A as one of the critical snoRNAs that regulate the proliferation and self-renewal of uMSC through snoRNP recruiting.