scholarly journals Icaritin requires Phosphatidylinositol 3 kinase (PI3K)/Akt signaling to counteract skeletal muscle atrophy following mechanical unloading

2016 ◽  
Vol 6 (1) ◽  
Author(s):  
Zong-Kang ZHANG ◽  
Jie LI ◽  
Jin LIU ◽  
Baosheng GUO ◽  
Albert LEUNG ◽  
...  
Keyword(s):  
Skeletal Muscle ◽  
Muscle Atrophy ◽  
Akt Signaling ◽  
Skeletal Muscle Atrophy ◽  
Phosphatidylinositol 3 Kinase ◽  
Mechanical Unloading ◽  
Phosphatidylinositol 3

scholarly journals Myotubularin Regulates Akt-dependent Survival Signaling via Phosphatidylinositol 3-Phosphate

2011 ◽  
Vol 286 (22) ◽  
pp. 20005-20019 ◽  
Author(s):  
Gina L. Razidlo ◽  
Dawn Katafiasz ◽  
Gregory S. Taylor
Keyword(s):  
Skeletal Muscle ◽  
Muscle Atrophy ◽  
Muscle Development ◽  
Critical Factor ◽  
Skeletal Muscle Atrophy ◽  
Phosphatidylinositol 3 Kinase ◽  
Myotubular Myopathy ◽  
Akt Activation ◽  
Survival Signaling ◽  
Phosphatidylinositol 3

Myotubularin is a 3-phosphoinositide phosphatase that is mutated in X-linked myotubular myopathy, a severe neonatal disorder in which skeletal muscle development and/or regeneration is impaired. In this report we provide evidence that siRNA-mediated silencing of myotubularin expression markedly inhibits growth factor-stimulated Akt phosphorylation, leading to activation of caspase-dependent pro-apoptotic signaling in HeLa cells and primary human skeletal muscle myotubes. Myotubularin silencing also inhibits Akt-dependent signaling through the mammalian target of rapamycin complex 1 as assessed by p70 S6-kinase and 4E-BP1 phosphorylation. Similarly, phosphorylation of FoxO transcription factors is also significantly reduced in myotubularin-deficient cells. Our data further suggest that inhibition of Akt activation and downstream survival signaling in myotubularin-deficient cells is caused by accumulation of the MTMR substrate lipid phosphatidylinositol 3-phosphate generated from the type II phosphatidylinositol 3-kinase PIK3C2B. Our findings are significant because they suggest that myotubularin regulates Akt activation via a cellular pool of phosphatidylinositol 3-phosphate that is distinct from that generated by the type III phosphatidylinositol 3-kinase hVps34. Because impaired Akt signaling has been tightly linked to skeletal muscle atrophy, we hypothesize that loss of Akt-dependent growth/survival cues due to impaired myotubularin function may be a critical factor underlying the severe skeletal muscle atrophy characteristic of muscle fibers in patients with X-linked myotubular myopathy.

Fam83d modulates MAP kinase and AKT signaling and is induced during neurogenic skeletal muscle atrophy

2020 ◽  
Vol 70 ◽  
pp. 109576 ◽  
Author(s):  
Lisa M. Cooper ◽  
Abby Hanson ◽  
Jack A. Kavanagh ◽  
David S. Waddell
Keyword(s):  
Skeletal Muscle ◽  
Map Kinase ◽  
Muscle Atrophy ◽  
Akt Signaling ◽  
Skeletal Muscle Atrophy

scholarly journals Nox2 Inhibition Regulates Stress Response and Mitigates Skeletal Muscle Fiber Atrophy during Simulated Microgravity

2021 ◽  
Vol 22 (6) ◽  
pp. 3252
Author(s):  
John M. Lawler ◽  
Jeffrey M. Hord ◽  
Pat Ryan ◽  
Dylan Holly ◽  
Mariana Janini Gomes ◽  
...  
Keyword(s):  
Skeletal Muscle ◽  
Stress Response ◽  
Muscle Atrophy ◽  
Muscle Fiber ◽  
Skeletal Muscle Atrophy ◽  
Positive Staining ◽  
Angiotensin Ii Receptor ◽  
Mechanical Unloading ◽  
Muscle Fiber Atrophy ◽  
Fiber Atrophy

Insufficient stress response and elevated oxidative stress can contribute to skeletal muscle atrophy during mechanical unloading (e.g., spaceflight and bedrest). Perturbations in heat shock proteins (e.g., HSP70), antioxidant enzymes, and sarcolemmal neuronal nitric oxidase synthase (nNOS) have been linked to unloading-induced atrophy. We recently discovered that the sarcolemmal NADPH oxidase-2 complex (Nox2) is elevated during unloading, downstream of angiotensin II receptor 1, and concomitant with atrophy. Here, we hypothesized that peptidyl inhibition of Nox2 would attenuate disruption of HSP70, MnSOD, and sarcolemmal nNOS during unloading, and thus muscle fiber atrophy. F344 rats were divided into control (CON), hindlimb unloaded (HU), and hindlimb unloaded +7.5 mg/kg/day gp91ds-tat (HUG) groups. Unloading-induced elevation of the Nox2 subunit p67phox-positive staining was mitigated by gp91ds-tat. HSP70 protein abundance was significantly lower in HU muscles, but not HUG. MnSOD decreased with unloading; however, MnSOD was not rescued by gp91ds-tat. In contrast, Nox2 inhibition protected against unloading suppression of the antioxidant transcription factor Nrf2. nNOS bioactivity was reduced by HU, an effect abrogated by Nox2 inhibition. Unloading-induced soleus fiber atrophy was significantly attenuated by gp91ds-tat. These data establish a causal role for Nox2 in unloading-induced muscle atrophy, linked to preservation of HSP70, Nrf2, and sarcolemmal nNOS.

scholarly journals Long Noncoding RNA lncMUMA Reverses Established Skeletal Muscle Atrophy following Mechanical Unloading

2018 ◽  
Vol 26 (11) ◽  
pp. 2669-2680 ◽  
Author(s):  
Zong-Kang Zhang ◽  
Jie Li ◽  
Daogang Guan ◽  
Chao Liang ◽  
Zhenjian Zhuo ◽  
...  
Keyword(s):  
Skeletal Muscle ◽  
Muscle Atrophy ◽  
Long Noncoding Rna ◽  
Noncoding Rna ◽  
Skeletal Muscle Atrophy ◽  
Mechanical Unloading

scholarly journals Standardized Kaempferia parviflora Wall. ex Baker (Zingiberaceae) Extract Inhibits Fat Accumulation and Muscle Atrophy in ob/ob Mice

2018 ◽  
Vol 2018 ◽  
pp. 1-11 ◽  
Author(s):  
Sunkyu Lee ◽  
Changhee Kim ◽  
Dowan Kwon ◽  
Mi-Bo Kim ◽  
Jae-Kwan Hwang
Keyword(s):  
Skeletal Muscle ◽  
Muscle Atrophy ◽  
Normal Diet ◽  
Skeletal Muscle Atrophy ◽  
Kaempferia Parviflora ◽  
Phosphatidylinositol 3 Kinase ◽  
Fat Accumulation ◽  
Exercise Endurance ◽  
Amp Activated Protein Kinase ◽  
Fat Volume

Obesity, a metabolic disorder caused by an imbalance between energy intake and energy expenditure, is accompanied with fat accumulation and skeletal muscle atrophy. Kaempferia parviflora Wall. ex Baker, also called black ginger, is known to increase physical fitness performance and improve energy metabolism. In this study, we investigated whether Kaempferia parviflora extract (KPE) alleviates both obesity and muscle atrophy using ob/ob mice. Wild-type C57BL/6J and ob/ob mice were provided with a normal diet ad libitum, and ob/ob mice were orally given KPE at a dose of 100 mg/kg/day or 200 mg/kg/day for eight weeks. KPE significantly decreased body weight, fat volume, and fat weight without affecting appetite. It inhibited the expression of adipogenic transcription factors and lipogenic enzymes by upregulating AMP-activated protein kinase (AMPK) in epididymal fat. In contrast, it markedly increased the muscle fiber size, muscle volume, and muscle mass, resulting in the enhancement of muscle function, such as exercise endurance and grip strength. On the molecular level, it activated the phosphatidylinositol 3 kinase (PI3K)/Akt pathway, a key regulator in protein synthesis in skeletal muscle. KPE could be a promising material to alleviate obesity by inhibiting adipogenesis, lipogenesis, and muscle atrophy.

The effect of icaritin on skeletal muscle atrophy following mechanical unloading

Planta Medica ◽  
2014 ◽  
Vol 80 (10) ◽  
Author(s):  
Z Zhang ◽  
WN Leung ◽  
G Zhang ◽  
J Li ◽  
BT Zhang
Keyword(s):  
Skeletal Muscle ◽  
Muscle Atrophy ◽  
Skeletal Muscle Atrophy ◽  
Mechanical Unloading
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