Department of Biotechnological and Applied Clinical Sciences, University of L'Aquila, Via Vetoio - Coppito 2, 67100 L'Aquila, Italy.
Department of Biotechnological and Applied Clinical Sciences, University of L'Aquila, Via Vetoio - Coppito 2, 67100 L'Aquila, Italy.
Bone. 2018 May;110:343-354. doi: 10.1016/j.bone.2018.02.031. Epub 2018 Mar 6.
Autosomal Dominant Osteopetrosis type 2 (ADO2) is a rare bone disease characterized by dense and brittle bones due to impairment of osteoclast bone resorption. Dominant negative mutations of the CLCN7 gene affect about 70% of ADO2 patients. ADO2 has no cure and our recent work established that it is suitable for gene silencing by a specific small interfering RNA that does not affect the normal mRNA, thus inducing a condition of pseudo-haplosufficiency and rescuing the bone phenotype. We performed a systematic study to test the likelihood that the therapy could progress towards clinical trials, treating Clcn7 ADO2 mice with Clcn7-specific siRNA and investigating the bone phenotype by μCT and histomorphometry, and safety, by histopathology and serology. We demonstrated that our Clcn7 siRNA is not only effective in pre-pubertal ADO2 male mice as we showed in our previous study, but also in adult and ageing mice, in males and females, by intraperitoneal and subcutaneous administration. Furthermore, the study also showed safety following prolonged chronic administration and allowed us to identify specific end-points to be potentially used in clinical trials. These results may pave the way towards regulatory toxicity studies, through which the therapy, that is patent-protected, can obtain approval from public health authorities for the transition to the Phase I/II clinical trials. The study also suggests that similar strategies could be applied to other autosomal dominant bone diseases, opening an avenue for a wider use of the RNA interference therapy in rare genetic disorders.
常染色体显性遗传骨硬化症 2 型（ADO2）是一种罕见的骨骼疾病，其特征是由于破骨细胞骨吸收受损导致骨骼致密和脆弱。CLCN7 基因突变的显性负性突变影响约 70%的 ADO2 患者。ADO2 无法治愈，我们最近的工作表明，它适合使用特定的小干扰 RNA 进行基因沉默，这种 RNA 不会影响正常的 mRNA，从而诱导假杂合不足的状态并挽救骨骼表型。我们进行了一项系统研究，以测试该疗法是否有可能进入临床试验，即用 Clcn7 特异性 siRNA 治疗 Clcn7ADO2 小鼠，并通过 μCT 和组织形态计量学研究骨骼表型，通过组织病理学和血清学研究安全性。我们证明，我们的 Clcn7 siRNA 不仅像我们之前的研究那样在青春期前的 ADO2 雄性小鼠中有效，而且在成年和老年小鼠中，无论是雄性还是雌性，通过腹腔内和皮下给药也有效。此外，该研究还表明，在长期慢性给药后具有安全性，并使我们能够确定潜在用于临床试验的特定终点。这些结果可能为监管毒理学研究铺平道路，通过该研究，受专利保护的治疗方法可以获得公共卫生当局的批准，从而过渡到 I/II 期临床试验。该研究还表明，类似的策略可以应用于其他常染色体显性遗传骨骼疾病，为 RNA 干扰疗法在罕见遗传疾病中的更广泛应用开辟了道路。
