Marchini Marta, Ashkin Mitchell R, Bellini Melina, Sun Margaret Man-Ger, Workentine Matthew Lloyd, Okuyan Hamza Malik, Krawetz Roman, Beier Frank, Rolian Campbell
Department of Anatomy and Cell Biology, Cumming School of Medicine, University of Calgary, Calgary, AB, Canada.
McCaig Institute for Bone and Joint Health, University of Calgary, Calgary, AB, Canada.
Front Cell Dev Biol. 2021 Dec 14;9:708384. doi: 10.3389/fcell.2021.708384. eCollection 2021.
The genetic and developmental mechanisms involved in limb formation are relatively well documented, but how these mechanisms are modulated by changes in chondrocyte physiology to produce differences in limb bone length remains unclear. Here, we used high throughput RNA sequencing (RNAseq) to probe the developmental genetic basis of variation in limb bone length in Longshanks, a mouse model of experimental evolution. We find that increased tibia length in Longshanks is associated with altered expression of a few key endochondral ossification genes such as and , as well reduced expression of a facultative subunit of the cell membrane-bound Na/K ATPase pump (NKA). Next, using murine tibia and cell cultures, we show a dynamic role for NKA in chondrocyte differentiation and in bone length regulation. Specifically, we show that pharmacological inhibition of NKA disrupts chondrocyte differentiation, by upregulating expression of mesenchymal stem cell markers (), downregulation of chondrogenesis marker , and altered expression of extracellular matrix genes (e.g., collagens) associated with proliferative and hypertrophic chondrocytes. Together, Longshanks and data suggest a broader developmental and evolutionary role of NKA in regulating limb length diversity.
参与肢体形成的遗传和发育机制已有相对充分的文献记载，但这些机制如何通过软骨细胞生理学变化进行调节以产生肢体骨长度差异仍不清楚。在这里，我们使用高通量RNA测序（RNAseq）来探究实验进化小鼠模型长胫鼠（Longshanks）肢体骨长度变异的发育遗传基础。我们发现，长胫鼠胫骨长度增加与一些关键的软骨内骨化基因（如……和……）表达改变有关，同时细胞膜结合的钠钾ATP酶泵（NKA）的一个兼性亚基表达降低。接下来，利用小鼠胫骨和细胞培养，我们展示了NKA在软骨细胞分化和骨长度调节中的动态作用。具体而言，我们表明对NKA的药理学抑制会破坏软骨细胞分化，通过上调间充质干细胞标志物（……）的表达、下调软骨生成标志物……以及改变与增殖性和肥大性软骨细胞相关的细胞外基质基因（如胶原蛋白）的表达。总之，长胫鼠模型和相关数据表明NKA在调节肢体长度多样性方面具有更广泛的发育和进化作用。
