Eriocitrin Contained in Lemon Peel Ameliorates Disuse Muscle Atrophy by Suppressing the Expression of Atrogin-1 and MuRF-1 in Denervated Mice

Author(s):  
Takahito Takase ◽  
Satoshi Ikeuchi ◽  
Takashi Inoue ◽  
Rie Mukai
2018 ◽  
Author(s):  
L John Hoffer

This review explains starvation as both a physiologic process and a disease. It includes a detailed explanation of the modifying effects of metabolic adaptation and systemic inflammation, as interpreted in a clinical context. It navigates the reader through the difficult shoals of vague and conflicting terminology that burden this topic and provides current definitions and nuanced explanations of the important but frequently misunderstood terms related to starvation and its modifiers and consequences. It provides a succinct explanation of the physiology of total fasting and its clinical correlates. Finally, it explains the interactions among starvation, sarcopenia, frailty, involuntary weight loss, systemic inflammation, cachexia, and disuse muscle atrophy. The multiple and interacting causes of generalized muscle atrophy are pointed out. Inadequate appreciation of these interactions can result in failure to diagnose and treat starvation-induced diseases. A clinical approach to involuntary weight loss is outlined.   This review contains 6 figures, 2 tables and 56 references Key words: adaptation, cachexia, frailty, hypoalbuminemia, inflammation, ketosis, kwashiorkor, malnutrition, marasmus, muscle atrophy, protein-energy malnutrition, sarcopenia, starvation, systemic inflammation, weight loss


2013 ◽  
Vol 114 (10) ◽  
pp. 1482-1489 ◽  
Author(s):  
Erin E. Talbert ◽  
Ashley J. Smuder ◽  
Kisuk Min ◽  
Oh Sung Kwon ◽  
Scott K. Powers

Prolonged skeletal muscle inactivity results in a rapid decrease in fiber size, primarily due to accelerated proteolysis. Although several proteases are known to contribute to disuse muscle atrophy, the ubiquitin proteasome system is often considered the most important proteolytic system during many conditions that promote muscle wasting. Emerging evidence suggests that calpain and caspase-3 may also play key roles in inactivity-induced atrophy of respiratory muscles, but it remains unknown if these proteases are essential for disuse atrophy in limb skeletal muscles. Therefore, we tested the hypothesis that activation of both calpain and caspase-3 is required for locomotor muscle atrophy induced by hindlimb immobilization. Seven days of immobilization (i.e., limb casting) promoted significant atrophy in type I muscle fibers of the rat soleus muscle. Independent pharmacological inhibition of calpain or caspase-3 prevented this casting-induced atrophy. Interestingly, inhibition of calpain activity also prevented caspase-3 activation, and, conversely, inhibition of caspase-3 prevented calpain activation. These findings indicate that a regulatory cross talk exists between these proteases and provide the first evidence that the activation of calpain and caspase-3 is required for inactivity-induced limb muscle atrophy.


2010 ◽  
Vol 42 ◽  
pp. 19
Author(s):  
Kisuk Min ◽  
Ashley J. Smuder ◽  
Oh-sung Kwon ◽  
Andreas N. Kavazis ◽  
Hazel H. Szeto ◽  
...  

2010 ◽  
Vol 42 ◽  
pp. 18 ◽  
Author(s):  
W. Bradley Nelson ◽  
Ashley J. Smuder ◽  
Matthew B. Hudson ◽  
Erin E. Talbert ◽  
Scott K. Powers

2010 ◽  
Vol 298 (1) ◽  
pp. C38-C45 ◽  
Author(s):  
Sarah M. Senf ◽  
Stephen L. Dodd ◽  
Andrew R. Judge

The purpose of the current study was to determine whether heat shock protein 70 (Hsp70) directly regulates forkhead box O (FOXO) signaling in skeletal muscle. This aim stems from previous work demonstrating that Hsp70 overexpression inhibits disuse-induced FOXO transactivation and prevents muscle fiber atrophy. However, although FOXO is sufficient to cause muscle wasting, no data currently exist on the requirement of FOXO signaling in the progression of physiological muscle wasting, in vivo. In the current study we show that specific inhibition of FOXO, via expression of a dominant-negative FOXO3a, in rat soleus muscle during disuse prevented >40% of muscle fiber atrophy, demonstrating that FOXO signaling is required for disuse muscle atrophy. Subsequent experiments determined whether Hsp70 directly regulates FOXO3a signaling when independently activated in skeletal muscle, via transfection of FOXO3a. We show that Hsp70 inhibits FOXO3a-dependent transcription in a gene-specific manner. Specifically, Hsp70 inhibited FOXO3a-induced promoter activation of atrogin-1, but not MuRF1. Further studies showed that a FOXO3a DNA-binding mutant can activate MuRF1, but not atrogin-1, suggesting that FOXO3a activates these two genes through differential mechanisms. In summary, FOXO signaling is required for physiological muscle atrophy and is directly inhibited by Hsp70.


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