Kuwakado So, Elgaabari Alaa, Zushi Kahona, Tanaka Sakiho, Seki Miyumi, Kaneko Ryuki, Matsuyoshi Yuji, Suzuki Takahiro, Kawaguchi Kenichi, Nakashima Yasuharu, Tatsumi Ryuichi
Department of Orthopaedic Surgery, Faculty of Medical Sciences, Kyushu University, Fukuoka, Japan.
Department of Animal and Marine Bioresource Sciences, Graduate School of Agriculture, Kyushu University, Fukuoka, Japan.
PLoS One. 2025 Sep 3;20(9):e0321839. doi: 10.1371/journal.pone.0321839. eCollection 2025.
Hepatocyte growth factor (HGF) is a key myogenic stem cell (satellite cells) activator, that resides in the extracellular matrix (ECM). However, HGF distribution in the ECM varies depending on the muscle fiber type. Furthermore, aging impedes the binding of HGF to its receptors owing to nitration by peroxynitrite (ONOO-). Though oxidative stress increases rapidly during muscle disuse atrophy, satellite cells are rapidly activated upon reloading. In this study, we investigated the distribution of HGF in the ECM in various muscle fiber types, and examined nitration of HGF in disuse and reloading models. Immunofluorescence staining was performed on the soleus (Sol), plantaris (Pla), and gastrocnemius (Gas) muscles of 10-week-old mice. Six mice were used to assess HGF distribution, while 12 mice, divided into control, disuse, and reloading groups were used for qualitative evaluation of nitrated HGF (nitroHGF). Student's t-tests and the Bonferroni correction were employed for statistical analysis (p < 0.05/3 = 0.0167). In Sol muscle, type IIa and IIx muscle fibers exhibited higher HGF distribution in the ECM (61.5 ± 1.0% and 56.7 ± 1.1%, respectively) than type I fibers (32.3 ± 1.0%; p < 0.001). In Pla and Gas muscle, type IIa 55.8 ± 0.9% and 58.8 ± 1.5%, respectively) and type IIx fibers (49.6 ± 0.9% and 48.9 ± 1.1%, respectively) had significantly higher HGF distribution in the ECM than type IIb fibers (18.6 ± 0.9% and 13.0 ± 1.0%; p < 0.001, respectively). The amount of nitroHGF increased in the disuse group compared to that in the control group but decreased in the reloading group compared to that in the disuse group. This preferential HGF distribution around type IIa and IIx muscle fibers indicates a distinct mechanism for satellite cell activation, differing from the satellite cell-rich environment associated with type I fibers and the lower HGF association with type IIb fibers. Disuse-induced HGF nitration may inhibit satellite cell activation. Reloading likely triggers mechanisms that counteract nitration, enabling satellite cell reactivation in young muscle.
肝细胞生长因子（HGF）是一种关键的生肌干细胞（卫星细胞）激活剂，存在于细胞外基质（ECM）中。然而，HGF在ECM中的分布因肌纤维类型而异。此外，衰老会由于过氧亚硝酸盐（ONOO-）的硝化作用而阻碍HGF与其受体的结合。尽管在肌肉废用性萎缩期间氧化应激迅速增加，但卫星细胞在重新加载时会迅速被激活。在本研究中，我们调查了HGF在各种肌纤维类型的ECM中的分布，并在废用和重新加载模型中检测了HGF的硝化作用。对10周龄小鼠的比目鱼肌（Sol）、跖肌（Pla）和腓肠肌（Gas）进行免疫荧光染色。6只小鼠用于评估HGF分布，而12只小鼠分为对照组、废用组和重新加载组，用于对硝化HGF（nitroHGF）进行定性评估。采用学生t检验和Bonferroni校正进行统计分析（p < 0.05/3 = 0.0167）。在Sol肌中，IIa型和IIx型肌纤维在ECM中的HGF分布（分别为61.5±1.0%和56.7±1.1%）高于I型纤维（32.3±1.0%；p < 0.001）。在Pla肌和Gas肌中，IIa型纤维（分别为55.8±0.9%和58.8±1.5%）和IIx型纤维（分别为49.6±0.9%和48.9±1.1%）在ECM中的HGF分布显著高于IIb型纤维（分别为18.6±0.9%和13.0±1.0%；p < 0.001）。与对照组相比，废用组中nitroHGF的量增加，但与废用组相比，重新加载组中nitroHGF的量减少。IIa型和IIx型肌纤维周围这种优先的HGF分布表明卫星细胞激活存在一种独特的机制，不同于与I型纤维相关的富含卫星细胞的环境以及与IIb型纤维较低的HGF关联。废用诱导的HGF硝化可能会抑制卫星细胞激活。重新加载可能触发抵消硝化作用的机制，从而使年轻肌肉中的卫星细胞重新激活。
