Department of Biological Science, Graduate School of Science, Hiroshima University, Kagamiyama 1-3-1, Higashi-Hiroshima, Hiroshima, 739-8526, Japan.
Hematology Business Development, HU Business Development, Sysmex Corporation, 4-4-4 Takatsukadai, Nishi-ku, Kobe, 651-2271, Japan.
Sci Rep. 2018 May 29;8(1):8278. doi: 10.1038/s41598-018-26664-2.
In animal regeneration, control of position-dependent cell proliferation is crucial for the complete restoration of patterned appendages in terms of both, shape and size. However, detailed mechanisms of this process are largely unknown. In this study, we identified leucine/glutamine and v-ATPase/lysosomal acidification, via mechanistic target of rapamycin complex 1 (mTORC1) activation, as effectors of amputation plane-dependent zebrafish caudal fin regeneration. mTORC1 activation, which functions in cell proliferation, was regulated by lysosomal acidification possibly via v-ATPase activity at 3 h post amputation (hpa). Inhibition of lysosomal acidification resulted in reduced growth factor-related gene expression and suppression of blastema formation at 24 and 48 hpa, respectively. Along the proximal-distal axis, position-dependent lysosomal acidification and mTORC1 activation were observed from 3 hpa. We also report that Slc7a5 (L-type amino acid transporter), whose gene expression is position-dependent, is necessary for mTORC1 activation upstream of lysosomal acidification during fin regeneration. Furthermore, treatment with leucine and glutamine, for both proximal and distal fin stumps, led to an up-regulation in cell proliferation via mTORC1 activation, indicating that leucine/glutamine signaling possesses the ability to change the position-dependent regeneration. Our findings reveal that leucine/glutamine and v-ATPase/lysosomal acidification via mTORC1 activation are required for position-dependent zebrafish fin regeneration.
在动物再生中，控制位置依赖性细胞增殖对于形态和大小方面的完整模式附肢的恢复至关重要。然而，这个过程的详细机制在很大程度上是未知的。在这项研究中，我们通过机制靶向雷帕霉素复合物 1 (mTORC1) 的激活，确定亮氨酸/谷氨酰胺和 v-ATPase/溶酶体酸化是斑马鱼尾鳍再生中截肢平面依赖性的效应物。mTORC1 激活通过溶酶体酸化起作用，可能通过 v-ATPase 活性在截肢后 3 小时 (hpa) 调节细胞增殖。溶酶体酸化的抑制导致生长因子相关基因表达减少，并分别在 24 和 48 hpa 时抑制芽基形成。在近-远轴上，从 3 hpa 开始观察到位置依赖性的溶酶体酸化和 mTORC1 激活。我们还报告说，Slc7a5（L 型氨基酸转运蛋白）的基因表达是位置依赖性的，在 fin 再生过程中，在溶酶体酸化的上游，它是 mTORC1 激活所必需的，用于亮氨酸/谷氨酰胺信号传导改变位置依赖性再生。此外，用亮氨酸和谷氨酰胺处理近端和远端鳍残端，通过 mTORC1 激活导致细胞增殖上调，表明亮氨酸/谷氨酰胺信号具有改变位置依赖性再生的能力。我们的研究结果表明，亮氨酸/谷氨酰胺和 v-ATPase/溶酶体酸化通过 mTORC1 激活是位置依赖性斑马鱼 fin 再生所必需的。
