Profilin-1 negatively controls osteoclast migration by suppressing the protrusive structures based on branched actin filaments
Profilin-1 negatively controls osteoclast migration by suppressing the protrusive structures based on branched actin filaments
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DOI：
10.1007/s00774-022-01320-y
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发表时间：
2022-04-15
影响因子：
3.3
通讯作者：
Nifuji, Akira
中科院分区：
文献类型：
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作者：
Kajikawa, Shuhei;Ezura, Yoichi;Nifuji, Akira
Profilin-1 （Pfn1）是一种进化保守的肌动蛋白结合蛋白，是细胞骨架的重要调节因子。我们之前报道了破骨细胞特异性pfn1条件敲除（cKO）小鼠的出生后溶骨表型，颅面和长骨畸形与培养的破骨细胞迁移增加有关。我们假设，在这些突变小鼠中，分支肌动蛋白丝结构的细胞过程增加可能是骨吸收增加的机制基础。材料与方法采用荧光显微镜和延时成像技术观察培养的破骨细胞的形态结构和细胞迁移情况。比较对照组和Pfn1-cKO小鼠细胞的分数迁移距离，以及评估相对边界长度的突出结构指数（%-PB）。结果延时图像分析显示Pfn1-cKO破骨细胞中%-PB明显增大。此外，分数迁移距离与该指数呈正相关。当化学抑制剂抑制分支肌动蛋白丝组织时，破骨细胞迁移减少。重要的是，这种抑制在Pfn1-cKO中比在对照破骨细胞中更为广泛。结论支状肌动蛋白丝的形成增加，至少是其过度迁移的部分原因。我们的研究结果为测试针对分支肌动蛋白丝治疗溶骨疾病的新治疗方法提供了机制基础。
Background Profilin-1 (Pfn1), an evolutionarily conserved actin-binding protein, is an important regulator of the cytoskeleton. We previously reported the osteoclast-specific Pfn1-conditional knockout (cKO) mice had postnatal osteolytic phenotype with craniofacial and long-bone deformities associated with increased migration of cultured osteoclasts. We hypothesized the increased cellular processes structured with branched actin filaments may underlies the mechanism of increased bone resorption in these mutant mice. Materials and methods The morphological structure and cell migration of the cultured osteoclasts were analyzed using fluorescent microscopy and time-lapse image capturing. Fractional migration distances, as well as the index of protrusive structures (%-PB) that evaluates relative border length of the protrusion were compared between the cells from control and Pfn1-cKO mice. Results Time-lapse image analysis showed that %-PB was significantly larger in Pfn1-cKO osteoclasts. In addition, the fractional migration distance was positively correlated with the index. When the branched actin filament organization was suppressed by chemical inhibitors, the osteoclast migration was declined. Importantly, the suppression was more extensive in Pfn1-cKO than in control osteoclasts. Conclusion Our results indicated the causative involvement of the increased branched actin filament formation at least in part for their excessive migration. Our findings provide a mechanistic rationale for testing novel therapeutic approaches targeting branched actin filaments in osteolytic disorders.