Abstract：
BACKGROUND: Muscle atrophy can cause muscle dysfunction and weakness. Krüppel-like factor 13 (KLF13), a central regulator of cellular energy metabolism, is highly expressed in skeletal muscles and implicated in the pathogenesis of several diseases. This study investigated the role of KLF13 in muscle atrophy, which could be a novel therapeutic target.
METHODS: The effects of gene knockdown and pharmacological targeting of KLF13 on skeletal muscle atrophy were investigated using cell-based and animal models. Clofoctol, an antibiotic and KLF13 agonist, was also investigated as a candidate for repurposing. The mechanisms related to skeletal muscle atrophy were assessed by measuring the expression levels and activation statuses of key regulatory pathways and validated using gene knockdown and RNA sequencing.
RESULTS: In a dexamethasone-induced muscle atrophy mouse model, the KLF13 knockout group had decreased muscle strength (N) (1.77 ± 0.10 vs. 1.48 ± 0.16, P < 0.01), muscle weight (%) [gastrocnemius (Gas): 76.0 ± 5.69 vs. 60.7 ± 7.23, P < 0.001; tibialis anterior (TA): 75.8 ± 6.21 vs. 67.5 ± 5.01, P < 0.05], and exhaustive running distance (m) (495.5 ± 64.8 vs. 315.5 ± 60.9, P < 0.05) compared with the control group. KLF13 overexpression preserved muscle mass (Gas: 100 ± 6.38 vs. 120 ± 14.4, P < 0.01) and the exhaustive running distance (423.8 ± 59.04 vs. 530.2 ± 77.45, P < 0.05) in an in vivo diabetes-induced skeletal muscle atrophy model. Clofoctol treatment protected against dexamethasone-induced muscle atrophy. Myotubes treated with dexamethasone, an atrophy-inducing glucocorticoid, were aggravated by KLF13 knockout, but anti-atrophic effects were achieved by inducing KLF13 overexpression. We performed a transcriptome analysis and luciferase reporter assays to further explore this mechanism, finding that delta-like 4 (Dll4) was a novel target gene of KLF13. The KLF13 transcript repressed Dll4, inhibiting the Dll4-Notch2 axis and preventing muscle atrophy. Dexamethasone inhibited KLF13 expression by inhibiting myogenic differentiation 1 (i.e., MYOD1)-mediated KLF13 transcriptional activation and promoting F-Box and WD repeat domain containing 7 (i.e., FBXW7)-mediated KLF13 ubiquitination.
CONCLUSIONS: This study sheds new light on the mechanisms underlying skeletal muscle atrophy and potential drug targets. KLF13 regulates muscle atrophy and is a potential therapeutic target. Clofoctol is an attractive compound for repurposing studies to treat skeletal muscle atrophy.
METHODS: The effects of gene knockdown and pharmacological targeting of KLF13 on skeletal muscle atrophy were investigated using cell-based and animal models. Clofoctol, an antibiotic and KLF13 agonist, was also investigated as a candidate for repurposing. The mechanisms related to skeletal muscle atrophy were assessed by measuring the expression levels and activation statuses of key regulatory pathways and validated using gene knockdown and RNA sequencing.
RESULTS: In a dexamethasone-induced muscle atrophy mouse model, the KLF13 knockout group had decreased muscle strength (N) (1.77 ± 0.10 vs. 1.48 ± 0.16, P < 0.01), muscle weight (%) [gastrocnemius (Gas): 76.0 ± 5.69 vs. 60.7 ± 7.23, P < 0.001; tibialis anterior (TA): 75.8 ± 6.21 vs. 67.5 ± 5.01, P < 0.05], and exhaustive running distance (m) (495.5 ± 64.8 vs. 315.5 ± 60.9, P < 0.05) compared with the control group. KLF13 overexpression preserved muscle mass (Gas: 100 ± 6.38 vs. 120 ± 14.4, P < 0.01) and the exhaustive running distance (423.8 ± 59.04 vs. 530.2 ± 77.45, P < 0.05) in an in vivo diabetes-induced skeletal muscle atrophy model. Clofoctol treatment protected against dexamethasone-induced muscle atrophy. Myotubes treated with dexamethasone, an atrophy-inducing glucocorticoid, were aggravated by KLF13 knockout, but anti-atrophic effects were achieved by inducing KLF13 overexpression. We performed a transcriptome analysis and luciferase reporter assays to further explore this mechanism, finding that delta-like 4 (Dll4) was a novel target gene of KLF13. The KLF13 transcript repressed Dll4, inhibiting the Dll4-Notch2 axis and preventing muscle atrophy. Dexamethasone inhibited KLF13 expression by inhibiting myogenic differentiation 1 (i.e., MYOD1)-mediated KLF13 transcriptional activation and promoting F-Box and WD repeat domain containing 7 (i.e., FBXW7)-mediated KLF13 ubiquitination.
CONCLUSIONS: This study sheds new light on the mechanisms underlying skeletal muscle atrophy and potential drug targets. KLF13 regulates muscle atrophy and is a potential therapeutic target. Clofoctol is an attractive compound for repurposing studies to treat skeletal muscle atrophy.
摘要：
背景：肌肉萎缩可导致肌肉功能障碍和无力。Krüppel样因子13（KLF13），细胞能量代谢的中央调节器，在骨骼肌中高度表达，并与几种疾病的发病机理有关。这项研究调查了KLF13在肌肉萎缩中的作用，这可能是一个新的治疗靶点。
方法：使用基于细胞和动物模型研究了KLF13的基因敲低和药理学靶向对骨骼肌萎缩的影响。Clofoctol,抗生素和KLF13激动剂,还被调查为重新利用的候选人。通过测量关键调节途径的表达水平和激活状态来评估与骨骼肌萎缩相关的机制，并使用基因敲低和RNA测序进行验证。
结果：在地塞米松诱导的肌肉萎缩小鼠模型中，KLF13敲除组肌肉力量（N）降低（1.77±0.10vs.1.48±0.16，P<0.01），肌肉重量（％）[腓肠肌（气体）：76.0±5.69vs.60.7±7.23，P<0.001；胫骨前肌（TA）：75.8±6.21vs.67.5±5.01,P<0.05],和穷举跑距离（m）（495.5±64.8vs.315.5±60.9,P<0.05)与对照组比较。KLF13过表达保留的肌肉质量（气体：100±6.38vs.120±14.4，P<0.01）和力竭跑距离（423.8±59.04vs.530.2±77.45，P<0.05）在体内糖尿病诱导的骨骼肌萎缩模型中。Clofoctol治疗可防止地塞米松诱导的肌肉萎缩。用地塞米松治疗的肌管，一种诱导萎缩的糖皮质激素，被KLF13击倒加剧了，但通过诱导KLF13过表达实现了抗萎缩性作用。我们进行了转录组分析和荧光素酶报告基因分析，以进一步探索这种机制，发现delta样4(Dll4)是KLF13的新靶基因。KLF13转录物抑制Dll4,抑制Dll4-Notch2轴并防止肌肉萎缩。地塞米松通过抑制肌源性分化1抑制KLF13表达(即，MYOD1）介导的KLF13转录激活和促进F-Box和WD重复结构域含有7（即，FBXW7)介导的KLF13泛素化。
结论：这项研究揭示了骨骼肌萎缩的潜在机制和潜在的药物靶点。KLF13调节肌肉萎缩，是一个潜在的治疗靶点。Clofoctol是一种有吸引力的化合物，可用于再利用研究以治疗骨骼肌萎缩。
方法：使用基于细胞和动物模型研究了KLF13的基因敲低和药理学靶向对骨骼肌萎缩的影响。Clofoctol,抗生素和KLF13激动剂,还被调查为重新利用的候选人。通过测量关键调节途径的表达水平和激活状态来评估与骨骼肌萎缩相关的机制，并使用基因敲低和RNA测序进行验证。
结果：在地塞米松诱导的肌肉萎缩小鼠模型中，KLF13敲除组肌肉力量（N）降低（1.77±0.10vs.1.48±0.16，P<0.01），肌肉重量（％）[腓肠肌（气体）：76.0±5.69vs.60.7±7.23，P<0.001；胫骨前肌（TA）：75.8±6.21vs.67.5±5.01,P<0.05],和穷举跑距离（m）（495.5±64.8vs.315.5±60.9,P<0.05)与对照组比较。KLF13过表达保留的肌肉质量（气体：100±6.38vs.120±14.4，P<0.01）和力竭跑距离（423.8±59.04vs.530.2±77.45，P<0.05）在体内糖尿病诱导的骨骼肌萎缩模型中。Clofoctol治疗可防止地塞米松诱导的肌肉萎缩。用地塞米松治疗的肌管，一种诱导萎缩的糖皮质激素，被KLF13击倒加剧了，但通过诱导KLF13过表达实现了抗萎缩性作用。我们进行了转录组分析和荧光素酶报告基因分析，以进一步探索这种机制，发现delta样4(Dll4)是KLF13的新靶基因。KLF13转录物抑制Dll4,抑制Dll4-Notch2轴并防止肌肉萎缩。地塞米松通过抑制肌源性分化1抑制KLF13表达(即，MYOD1）介导的KLF13转录激活和促进F-Box和WD重复结构域含有7（即，FBXW7)介导的KLF13泛素化。
结论：这项研究揭示了骨骼肌萎缩的潜在机制和潜在的药物靶点。KLF13调节肌肉萎缩，是一个潜在的治疗靶点。Clofoctol是一种有吸引力的化合物，可用于再利用研究以治疗骨骼肌萎缩。
