Hippo Pathway and Skeletal Muscle Mass Regulation in Mammals: A Controversial Relationship

Abstract

Skeletal muscle mass reflects a dynamic turnover between net protein synthesis and degradation. In addition, satellite cell inclusion may contribute to increase muscle mass while fiber loss results in a reduction of muscle mass. Since 2010, a few studies looked at the involvement of the newly discovered Hippo pathway in the regulation of muscle mass. In line with its roles in other organs, it has been hypothesized that the Hippo pathway could play a role in different regulatory mechanisms in skeletal muscle as well, namely proliferation and renewal of satellite cells, differentiation, death, and growth of myogenic cells. While the Hippo components have been identified in skeletal muscle, their role in muscle mass regulation has been less investigated and conflicting results have been reported. Indeed, the first studies described both atrophic and hypertrophic roles of the Hippo pathway and its effectors Yap/Taz using different biochemical approaches. Further, investigation is therefore warranted to determine the role of the Hippo pathway in the regulation of skeletal muscle mass. New components of the pathway will probably emerge and unsuspected roles will likely be discovered due to its numerous interactions with different cellular processes. This mini-review aims to summarize the current literature concerning the roles of the Hippo pathway in the regulation of muscle mass and to develop the hypothesis that this pathway could contribute to muscle mass adaptation after exercise.

Acute environmental hypoxia potentiates satellite cell‐dependent myogenesis in response to resistance exercise through the inflammation pathway in human

“…6 Resistance training is a well-known strategy to induce skeletal muscle hypertrophy notably through protein synthesis activation, proteolysis inhibition, and activation of the myogenic program. [8][9][10][11][12][13] Although chronic hypoxia induces skeletal muscle wasting, 14 intermittent hypoxia has recently been identified as an efficient stimulus to promote satellite cell proliferation and muscle protein accretion. [8][9][10][11][12][13] Although chronic hypoxia induces skeletal muscle wasting, 14 intermittent hypoxia has recently been identified as an efficient stimulus to promote satellite cell proliferation and muscle protein accretion.…”

Local Vibration Stimuli Induce Mechanical Stress-Induced Factors and Facilitate Recovery From Immobilization-Induced Oxidative Myofiber Atrophy in Rats

“…Various stresses cause different types of muscle fiber atrophy: aging processes mainly cause atrophy of type II fibers, while unloading stress leads to type I fiber atrophy. In addition, stress-induced fiber transition, from slow oxidative to fast glycolytic fiber types, has been reported in unloading models such as the environment of spaceflight/microgravity and hindlimb suspension (Baldwin et al, 2013); however, the mechanisms underlying different fiber type atrophy, fiber transition, and the regenerative processes remain unknown, although some associated factors such as mechano growth factor (MGF), systemic variant of insulin-like growth factor (IGF-I), Hippo pathway, and muscle stem cells have been reported (Goldspink, 1999; Kandalla et al, 2011; Brooks and Myburgh, 2014; Gnimassou et al, 2017; Fukada, 2018).…”

Examining the Genetic Background of Porcine Muscle Growth and Development Based on Transcriptome and miRNAome Data

“…Numerous studies have shown that the Hippo signalling pathway plays a key role in muscle cell proliferation, differentiation and apoptosis and, as a result, controls myogenesis processes [ 24 , 29 , 30 , 31 ]. The Hippo signal transduction network can regulate muscle mass and organ size via the activation of cascades of serine/threonine kinases [ 32 , 33 ]. Moreover, Gnimassou et al [ 33 ] suggested that this pathway can contribute to changes and adaptation of muscle mass after exercise.…”

“…The Hippo signal transduction network can regulate muscle mass and organ size via the activation of cascades of serine/threonine kinases [ 32 , 33 ]. Moreover, Gnimassou et al [ 33 ] suggested that this pathway can contribute to changes and adaptation of muscle mass after exercise. microRNAs identified in the present study can be upstream regulators of the Hippo pathway and, as described previously, are considered to be myomiRs closely related to muscle growth.…”