肌肉再生,代表一个基本的体内平衡过程,主要依赖于常驻卫星细胞的肌源性进展,它由多种物理和营养因素调节。这里,我们研究了肌源性分化相关因子和途径如何响应快速和慢速肌肉中的第一个限制性氨基酸赖氨酸(Lys),和他们的卫星细胞(SC),猪。30只体重相似的28日龄断奶仔猪接受三种饮食方案:对照组(d0-28:1.31%Lys,n=12),Lys缺乏组(d0-28:0.83%Lys,n=12),和Lys救援组(d0-14:0.83%Lys;d15-28:1.31%Lys,n=6)。对第15天和第29天的猪进行选择性屠宰以进行肌肉参数评估。还选择了从快速(半膜)和慢速(半腱肌)肌肉分离的卫星细胞来研究分化能力的变化。我们发现Lys缺乏通过对肌源性调节因子和Wnt/Ca2途径的独特操纵显着阻碍了快速和慢速肌肉的肌肉发育。在SC模型中,Lys缺乏抑制Wnt/Ca2+途径和肌球蛋白重链,Myogenin,和肌源性调节因子4在慢肌SCs中,但在快肌SCs中刺激它们。当获得足够的Lys时,快肌来源的SCsWnt/Ca2+途径(蛋白激酶C,钙调磷酸酶,钙/钙调蛋白依赖性蛋白激酶II,和活化T细胞核因子1)被抑制,同时刺激其对应物的Wnt/Ca2途径以进一步促进肌源性分化。Lys可能以相反的趋势通过Wnt/Ca2途径操纵猪慢肌纤维和快肌纤维的分化。
Muscle regeneration, representing an essential homeostatic process, relies mainly on the myogenic progress of resident satellite cells, and it is modulated by multiple physical and nutritional factors. Here, we investigated how myogenic differentiation-related factors and pathways respond to the first limiting amino acid lysine (Lys) in the fast and slow muscles, and their satellite cells (SCs), of swine. Thirty 28-day-old weaned piglets with similar body weights were subjected to three diet regimens: control group (d 0-28: 1.31% Lys, n = 12), Lys-deficient group (d 0-28: 0.83% Lys, n = 12), and Lys rescue group (d 0-14: 0.83% Lys; d 15-28: 1.31% Lys, n = 6). Pigs on d 15 and 29 were selectively slaughtered for muscular parameters evaluation. Satellite cells isolated from fast (semimembranosus) and slow (semitendinosus) muscles were also selected to investigate differentiation ability variations. We found Lys deficiency significantly hindered muscle development in both fast and slow muscles via the distinct manipulation of myogenic regulatory factors and the Wnt/Ca2+ pathway. In the SC model, Lys deficiency suppressed the Wnt/Ca2+ pathways and myosin heavy chain, myogenin, and myogenic regulatory factor 4 in slow muscle SCs but stimulated them in fast muscle SCs. When sufficient Lys was attained, the fast muscle-derived SCs Wnt/Ca2+ pathway (protein kinase C, calcineurin, calcium/calmodulin-dependent protein kinase II, and nuclear factor of activated T cells 1) was repressed, while the Wnt/Ca2+ pathway of its counterpart was stimulated to further the myogenic differentiation. Lys potentially manipulates the differentiation of porcine slow and fast muscle myofibers via the Wnt/Ca2+ pathway in opposite trends.