Collagen VI (COL6) is an extracellular matrix protein exerting multiple functions in different tissues. In humans, mutations of COL6 genes cause rare inherited congenital disorders, primarily affecting skeletal muscles and collectively known as COL6-related myopathies, for which no cure is available yet. In order to get insights into the pathogenic mechanisms underlying COL6-related diseases, diverse animal models were produced. However, the roles exerted by COL6 during embryogenesis remain largely unknown. Here, we generated the first zebrafish COL6 knockout line through CRISPR/Cas9 site-specific mutagenesis of the col6a1 gene. Phenotypic characterization during embryonic and larval development revealed that lack of COL6 leads to neuromuscular defects and motor dysfunctions, together with distinctive alterations in the three-dimensional architecture of craniofacial cartilages. These phenotypic features were maintained in adult col6a1 null fish, which displayed defective muscle organization and impaired swimming capabilities. Moreover, col6a1 null fish showed autophagy defects and organelle abnormalities at both embryonic and adult stages, thus recapitulating the main features of patients affected by COL6-related myopathies. Mechanistically, lack of COL6 led to increased BMP signaling, and direct inhibition of BMP activity ameliorated the locomotor activity of col6a1 null embryos. Finally, treatment with salbutamol, a β₂-adrenergic receptor agonist, elicited a significant amelioration of the neuromuscular and motility defects of col6a1 null fish embryos. Altogether, these findings indicate that this newly generated zebrafish col6a1 null line is a valuable in vivo tool to model COL6-related myopathies and suitable for drug screenings aimed at addressing the quest for effective therapeutic strategies for these disorders.

胶原蛋白 VI (COL6) 是一种细胞外基质蛋白，在不同组织中发挥多种功能。在人类中，COL6 基因突变导致罕见的遗传性先天性疾病，主要影响骨骼肌，统称为 COL6 相关肌病，目前尚无治愈方法。为了深入了解 COL6 相关疾病的致病机制，制作了多种动物模型。然而，COL6 在胚胎发生过程中发挥的作用在很大程度上仍然未知。在这里，我们通过 col6a1 的 CRISPR/Cas9 位点特异性诱变生成了第一个斑马鱼 COL6 基因敲除系基因。胚胎和幼虫发育过程中的表型特征表明，缺乏 COL6 会导致神经肌肉缺陷和运动功能障碍，以及颅面软骨三维结构的明显改变。这些表型特征在成年col6a1无效鱼中得以保留，这些鱼显示出肌肉组织缺陷和游泳能力受损。此外，col6a1缺失鱼在胚胎期和成年期均表现出自噬缺陷和细胞器异常，从而概括了受 COL6 相关肌病影响的患者的主要特征。从机制上讲，缺乏 COL6 会导致 BMP 信号增加，而直接抑制 BMP 活性可改善col6a1的运动活性无效胚胎。最后，用沙丁胺醇（一种 β ₂肾上腺素能受体激动剂）治疗可显着改善col6a1缺失鱼胚胎的神经肌肉和运动缺陷。总而言之，这些发现表明这种新生成的斑马鱼col6a1无效系是一种有价值的体内工具，可以模拟 COL6 相关的肌病，并且适用于旨在解决这些疾病有效治疗策略的药物筛选。