Mesenchymal stem cells (MSC) are an important type of cell that are highly recognized for their safety and efficacy as a cell therapy agent. In order to obtain MSC, primary tissues (adipose tissue, bone marrow, and umbilical cord blood) must be used; however, these tissues, especially umbilical cord blood, are difficult to obtain due to various reasons, such as the low birth rate trend. In addition, to maximize the safety and efficacy of MSC as allogenic cell therapeutic agents, it is desirable to minimize the possibility of an immune rejection reaction after in vivo transplantation. This study tried to establish a novel method for producing induced pluripotent stem cells (iPSC)-derived MSC in which the human leukocyte antigen (HLA)-class I gene is knocked out. To do so, dermal fibroblast originated iPSC generation using Yamanaka 4-factor, HLA class I gene edited iPSC generation using CRISPR/Cas9, and differentiation from iPSC to MSC using MSC culture medium was utilized. Through this, HLA-A, B, and C pseudo-homozygous iPSC-derived MSC (KO iMSC) were produced by monoallelically knocking out the polymorphic HLA-A, B, and C genes, which are the major causes of immune rejection during allogenic cell transplantation. Produced KO iMSC possesses multipotency and it was safe in vivo to be able to be differentiated to cartilage. In addition, it was not attacked by natural killer cells unlike HLA class I null cells. In conclusion, KO iMSC that do not induce immune rejection during allogenic cell transplantation can be produced. In the future, KO iMSC can be successfully utilized as allogenic cell therapeutic agents for many recipients through HLA screening.

中文翻译：

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源自人诱导的多能干细胞的人白细胞抗原I类伪纯合间充质干细胞。

间充质干细胞（MSC）是一种重要的细胞类型，以其作为细胞治疗剂的安全性和有效性而广受认可。为了获得MSC，必须使用原发组织（脂肪组织，骨髓和脐带血）。然而，由于诸如低出生率趋势之类的各种原因，难以获得这些组织，特别是脐带血。另外，为了使MSC作为同种异体细胞治疗剂的安全性和效力最大化，期望使体内移植后免疫排斥反应的可能性最小化。这项研究试图建立一种新的方法来生产诱导多能干细胞（iPSC）衍生的MSC，其中人类白细胞抗原（HLA）I类基因被敲除。为此，使用Yamanaka 4因子，真皮成纤维细胞起源于iPSC代，HLA I类基因使用CRISPR / Cas9编辑iPSC生成，并利用MSC培养基从iPSC分化为MSC。通过这种方法，通过单等位敲除多态性HLA-A，B和C基因，产生了HLA-A，B和C假纯合iPSC衍生的MSC（KO iMSC），这是同种异体免疫排斥的主要原因细胞移植。产生的KO iMSC具有多能性，能够在体内分化为软骨是安全的。此外，它不像HLA I类空细胞那样受到自然杀伤细胞的攻击。总之，可以产生在异源细胞移植过程中不诱导免疫排斥的KO iMSC。将来，通过HLA筛选，KO iMSC可以成功地用作许多受体的同种异体细胞治疗剂。