Dyskeratosis congenita (DC) is a rare telomere biology disorder, which results in different clinical manifestations, including severe bone marrow failure. To date, the only curative treatment for the bone marrow failure in DC patients is allogeneic hematopoietic stem cell transplantation. However, due to the toxicity associated to this treatment, improved therapies are recommended for DC patients. Here, we aimed at generating DC-like human hematopoietic stem cells in which the efficacy of innovative therapies could be investigated. Because X-linked DC is the most frequent form of the disease and is associated with an impaired expression of DKC1, we have generated DC-like hematopoietic stem cells based on the stable knock-down of DKC1 in human CD34+ cells with lentiviral vectors encoding for DKC1 short hairpin RNAs. At a molecular level, DKC1-interfered CD34+ cells showed a decreased expression of TERC, as well as a diminished telomerase activity and increased DNA damage, cell senescence, and apoptosis. Moreover, DKC1-interfered human CD34+ cells showed defective clonogenic ability and were incapable of repopulating the hematopoiesis of immunodeficient NSG mice. The development of DC-like hematopoietic stem cells will facilitate the understanding of the molecular and cellular basis of this inherited bone marrow failure syndrome and will serve as a platform to evaluate the efficacy of new hematopoietic therapies for DC.

中文翻译：

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通过稳定地抑制DKC1生成角化不全先天性造血干细胞

先天性角化病（DC）是一种罕见的端粒生物学疾病，其导致不同的临床表现，包括严重的骨髓衰竭。迄今为止，DC患者中唯一治疗骨髓衰竭的方法是同种异体造血干细胞移植。但是，由于与这种治疗相关的毒性，因此建议对DC患者采用更好的治疗方法。在这里，我们旨在生成DC样的人类造血干细胞，在其中可以研究创新疗法的功效。由于X连锁的DC是该病最常见的形式，并且与DKC1的表达受损有关，我们基于DKC1在人CD34 +细胞中的稳定敲低以及慢病毒载体编码产生了DC样造血干细胞。 DKC1短发夹RNA。在分子水平上 DKC1干扰的CD34 +细胞显示TERC的表达降低，端粒酶活性降低，DNA损伤，细胞衰老和凋亡增加。此外，DKC1干扰的人CD34 +细胞显示出克隆能力不足，并且无法重新填充免疫缺陷NSG小鼠的造血功能。DC样造血干细胞的发展将促进对该遗传性骨髓衰竭综合征的分子和细胞基础的理解，并将作为评估DC新造血疗法疗效的平台。DKC1干扰的人CD34 +细胞显示出克隆能力不足，并且无法重新填充免疫缺陷NSG小鼠的造血功能。DC样造血干细胞的发展将促进对该遗传性骨髓衰竭综合征的分子和细胞基础的理解，并将作为评估DC新造血疗法疗效的平台。DKC1干扰的人CD34 +细胞显示出克隆能力不足，并且无法重新填充免疫缺陷NSG小鼠的造血功能。DC样造血干细胞的发展将促进对该遗传性骨髓衰竭综合征的分子和细胞基础的理解，并将作为评估DC新造血疗法疗效的平台。