期刊名称：Proceedings of the National Academy of Sciences
印刷版ISSN：0027-8424
电子版ISSN：1091-6490
出版年度：2016
卷号：113
期号：28
页码：7840-7845
DOI：10.1073/pnas.1522054113
语种：English
出版社：The National Academy of Sciences of the United States of America
摘要：Cell-based or pharmacological approaches for promoting tendon repair are currently not available because the molecular mechanisms of tendon development and healing are not well understood. Although analysis of knockout mice provides many critical insights, small animals such as mice have some limitations. In particular, precise physiological examination for mechanical load and the ability to obtain a sufficient number of primary tendon cells for molecular biology studies are challenging using mice. Here, we generated Mohawk (Mkx)−/− rats by using CRISPR/Cas9, which showed not only systemic hypoplasia of tendons similar to Mkx−/− mice, but also earlier heterotopic ossification of the Achilles tendon compared with Mkx−/− mice. Analysis of tendon-derived cells (TDCs) revealed that Mkx deficiency accelerated chondrogenic and osteogenic differentiation, whereas Mkx overexpression suppressed chondrogenic, osteogenic, and adipogenic differentiation. Furthermore, mechanical stretch stimulation of Mkx−/− TDCs led to chondrogenic differentiation, whereas the same stimulation in Mkx+/+ TDCs led to formation of tenocytes. ChIP-seq of Mkx overexpressing TDCs revealed significant peaks in tenogenic-related genes, such as collagen type (Col)1a1 and Col3a1, and chondrogenic differentiation-related genes, such as SRY-box (Sox)5, Sox6, and Sox9. Our results demonstrate that Mkx has a dual role, including accelerating tendon differentiation and preventing chondrogenic/osteogenic differentiation. This molecular network of Mkx provides a basis for tendon physiology and tissue engineering.
关键词：tendon development ; Mkx ; knockout rat ; CRISPR-Cas9 ; Achilles tendon ossification
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