Department of Biomedicine, Aarhus University, Aarhus, Denmark.
Department of Molecular Biology and Genetics, Aarhus University, Aarhus, Denmark.
Free Radic Biol Med. 2021 Feb 20;164:399-409. doi: 10.1016/j.freeradbiomed.2021.01.027. Epub 2021 Jan 19.
Superoxide dismutase 3 (SOD3) is an extracellular protein with the capacity to convert superoxide into hydrogen peroxide, an important secondary messenger in redox regulation. To investigate the utility of zebrafish in functional studies of SOD3 and its relevance for redox regulation, we have characterized the zebrafish orthologues; Sod3a and Sod3b. Our analyses show that both recombinant Sod3a and Sod3b express SOD activity, however, only Sod3b is able to bind heparin. Furthermore, RT-PCR analyses reveal that sod3a and sod3b are expressed in zebrafish embryos and are present primarily in separate organs in adult zebrafish, suggesting distinct functions in vivo. Surprisingly, both RT-PCR and whole mount in situ hybridization showed specific expression of sod3b in skeletal tissue. To further investigate this observation, we compared femoral bone obtained from wild-type and SOD3 mice to determine whether a functional difference was apparent in healthy adult mice. Here we report, that bone from SOD3 mice is less mineralized and characterized by significant reduction of cortical and trabecular thickness in addition to reduced mechanical strength. These analyses show that SOD3 plays a hitherto unappreciated role in bone development and homeostasis.
超氧化物歧化酶 3（SOD3）是一种具有将超氧化物转化为过氧化氢能力的细胞外蛋白，过氧化氢是氧化还原调节中的重要二级信使。为了研究斑马鱼在 SOD3 功能研究及其与氧化还原调节相关性中的应用，我们对其同源物；Sod3a 和 Sod3b 进行了特征描述。我们的分析表明，重组 Sod3a 和 Sod3b 均表达 SOD 活性，但只有 Sod3b 能够结合肝素。此外，RT-PCR 分析表明 sod3a 和 sod3b 在斑马鱼胚胎中表达，并在成年斑马鱼中主要存在于不同的器官中，提示其在体内具有不同的功能。令人惊讶的是，RT-PCR 和全胚胎原位杂交均显示 sod3b 在骨骼组织中有特异性表达。为了进一步研究这一观察结果，我们比较了来自野生型和 SOD3 小鼠的股骨，以确定在健康成年小鼠中是否存在明显的功能差异。在这里，我们报告 SOD3 小鼠的骨骼矿化程度较低，皮质和小梁厚度明显减少，机械强度降低。这些分析表明 SOD3 在骨骼发育和稳态中发挥了迄今为止尚未被认识的作用。
