Lack of Smad3 signaling leads to impaired skeletal muscle regeneration

2012 ◽  
Vol 303 (1) ◽  
pp. E90-E102 ◽  
Author(s):  
Xiaojia Ge ◽  
Anuradha Vajjala ◽  
Craig McFarlane ◽  
Walter Wahli ◽  
Mridula Sharma ◽  
...  

Smad3 is a key intracellular signaling mediator for both transforming growth factor-β and myostatin, two major regulators of skeletal muscle growth. Previous published work has revealed pronounced muscle atrophy together with impaired satellite cell functionality in Smad3-null muscles. In the present study, we have further validated a role for Smad3 signaling in skeletal muscle regeneration. Here, we show that Smad3-null mice had incomplete recovery of muscle weight and myofiber size after muscle injury. Histological/immunohistochemical analysis suggested impaired inflammatory response and reduced number of activated myoblasts during the early stages of muscle regeneration in the tibialis anterior muscle of Smad3-null mice. Nascent myofibers formed after muscle injury were also reduced in number. Moreover, Smad3-null regenerated muscle had decreased oxidative enzyme activity and impaired mitochondrial biogenesis, evident by the downregulation of the gene encoding mitochondrial transcription factor A, a master regulator of mitochondrial biogenesis. Consistent with known Smad3 function, reduced fibrotic tissue formation was also seen in regenerated Smad3-null muscle. In conclusion, Smad3 deficiency leads to impaired muscle regeneration, which underscores an essential role of Smad3 in postnatal myogenesis. Given the negative role of myostatin during muscle regeneration, the increased expression of myostatin observed in Smad3-null muscle may contribute to the regeneration defects.

2015 ◽  
Vol 309 (2) ◽  
pp. E122-E131 ◽  
Author(s):  
Preeti Chandrashekar ◽  
Ravikumar Manickam ◽  
Xiaojia Ge ◽  
Sabeera Bonala ◽  
Craig McFarlane ◽  
...  

Peroxisome proliferator-activated receptor β/δ ( PPARβ/δ) is a ubiquitously expressed gene with higher levels observed in skeletal muscle. Recently, our laboratory showed (Bonala S, Lokireddy S, Arigela H, Teng S, Wahli W, Sharma M, McFarlane C, Kambadur R. J Biol Chem 287: 12935–12951, 2012) that PPARβ/δ modulates myostatin activity to induce myogenesis in skeletal muscle. In the present study, we show that PPARβ/δ-null mice display reduced body weight, skeletal muscle weight, and myofiber atrophy during postnatal development. In addition, a significant reduction in satellite cell number was observed in PPARβ/δ-null mice, suggesting a role for PPARβ/δ in muscle regeneration. To investigate this, tibialis anterior muscles were injured with notexin, and muscle regeneration was monitored on days 3, 5, 7, and 28 postinjury. Immunohistochemical analysis revealed an increased inflammatory response and reduced myoblast proliferation in regenerating muscle from PPARβ/δ-null mice. Histological analysis confirmed that the regenerated muscle fibers of PPARβ/δ-null mice maintained an atrophy phenotype with reduced numbers of centrally placed nuclei. Even though satellite cell numbers were reduced before injury, satellite cell self-renewal was found to be unaffected in PPARβ/δ-null mice after regeneration. Previously, our laboratory had showed (Bonala S, Lokireddy S, Arigela H, Teng S, Wahli W, Sharma M, McFarlane C, Kambadur R. J Biol Chem 287: 12935–12951, 2012) that inactivation of PPARβ/δ increases myostatin signaling and inhibits myogenesis. Our results here indeed confirm that inactivation of myostatin signaling rescues the atrophy phenotype and improves muscle fiber cross-sectional area in both uninjured and regenerated tibialis anterior muscle from PPARβ/δ-null mice. Taken together, these data suggest that absence of PPARβ/δ leads to loss of satellite cells, impaired skeletal muscle regeneration, and postnatal myogenesis. Furthermore, our results also demonstrate that functional antagonism of myostatin has utility in rescuing these effects.


2019 ◽  
Vol 30 (12) ◽  
pp. 1553-1598 ◽  
Author(s):  
Francesca De Santa ◽  
Laura Vitiello ◽  
Alessio Torcinaro ◽  
Elisabetta Ferraro

1996 ◽  
Vol 21 (4) ◽  
pp. 236-250 ◽  
Author(s):  
Jamie MacGregor ◽  
Wade S. Parkhouse

The role of the insulin-like growth factors I and II (IGF-I and IGF-II), previously known as the somatomedins, in general growth and development of various tissues has been known for many years. Thought of exclusively as endocrine factors produced by the liver, and under the control of growth hormone, the somatomedins were known as the intermediaries by which growth hormone exerted its cellular effects during tissue growth and maturation. Eventually it was discovered that virtually every tissue type is capable of autocrine production of the IGFs, and their involvement in skeletal muscle tissue repair and regeneration became apparent. Recent advances in technology have allowed the characterisation of many of the different growth factors believed to play a role in muscle regeneration, and experimental manipulations of cells in culture have provided insight into the effects of the various growth factors on the myoblast. This paper explores the potential role of the IGFs in skeletal muscle regeneration. A critical role of IGF-II in terminal differentiation of proliferating muscle precurser cells following injury is proposed. Key words: growth factors, myogenesis, skeletal muscle regeneration


2021 ◽  
Author(s):  
Kentaro Fukuda ◽  
Taisuke Kuroda ◽  
Norihisa Tamura ◽  
Hiroshi Mita ◽  
Hirofumi Miyata ◽  
...  

2019 ◽  
Vol 20 (22) ◽  
pp. 5686 ◽  
Author(s):  
Satoshi Oikawa ◽  
Minjung Lee ◽  
Takayuki Akimoto

Skeletal muscle has a remarkable regenerative capacity, which is orchestrated by multiple processes, including the proliferation, fusion, and differentiation of the resident stem cells in muscle. MicroRNAs (miRNAs) are small noncoding RNAs that mediate the translational repression or degradation of mRNA to regulate diverse biological functions. Previous studies have suggested that several miRNAs play important roles in myoblast proliferation and differentiation in vitro. However, their potential roles in skeletal muscle regeneration in vivo have not been fully established. In this study, we generated a mouse in which the Dicer gene, which encodes an enzyme essential in miRNA processing, was knocked out in a tamoxifen-inducible way (iDicer KO mouse) and determined its regenerative potential after cardiotoxin-induced acute muscle injury. Dicer mRNA expression was significantly reduced in the tibialis anterior muscle of the iDicer KO mice, whereas the expression of muscle-enriched miRNAs was only slightly reduced in the Dicer-deficient muscles. After cardiotoxin injection, the iDicer KO mice showed impaired muscle regeneration. We also demonstrated that the number of PAX7+ cells, cell proliferation, and the myogenic differentiation capacity of the primary myoblasts did not differ between the wild-type and the iDicer KO mice. Taken together, these data demonstrate that Dicer is a critical factor for muscle regeneration in vivo.


2017 ◽  
Vol 41 (7) ◽  
pp. 706-715 ◽  
Author(s):  
Kamila Delaney ◽  
Paulina Kasprzycka ◽  
Maria Anna Ciemerych ◽  
Malgorzata Zimowska

2002 ◽  
Vol 50 (12) ◽  
pp. 1579-1589 ◽  
Author(s):  
Katsuya Kami ◽  
Emiko Senba

Although growth factors and cytokines play critical roles in skeletal muscle regeneration, intracellular signaling molecules that are activated by these factors in regenerating muscles have been not elucidated. Several lines of evidence suggest that leukemia inhibitory factor (LIF) is an important cytokine for the proliferation and survival of myoblasts in vitro and acceleration of skeletal muscle regeneration. To elucidate the role of LIF signaling in regenerative responses of skeletal muscles, we examined the spatial and temporal activation patterns of an LIF-associated signaling molecule, the signal transducer and activator transcription 3 (STAT3) proteins in regenerating rat skeletal muscles induced by crush injury. At the early stage of regeneration, activated STAT3 proteins were first detected in the nuclei of activated satellite cells and then continued to be activated in proliferating myoblasts expressing both PCNA and MyoD proteins. When muscle regeneration progressed, STAT3 signaling was no longer activated in differentiated myoblasts and myotubes. In addition, activation of STAT3 was also detected in myonuclei within intact sarcolemmas of surviving myofibers that did not show signs of necrosis. These findings suggest that activation of STAT3 signaling is an important molecular event that induces the successful regeneration of injured skeletal muscles.


2021 ◽  
Author(s):  
David Ollitrault ◽  
Valentina Buffa ◽  
Rosamaria Correra ◽  
Angeliqua Sayed ◽  
Benedicte Hoareau ◽  
...  

Skeletal muscle injury results in a disruption of the muscle bed vascular network. A local source of vascular progenitors during muscle regeneration has not been clearly identified. Fibroadipogenic progenitors (FAPs) are required for proper regeneration, however they can also directly contribute to fibrotic and fatty infiltration in response to chronic muscle injury and muscle disease. We show here that acute muscle injury leads to hypoxia and glucose deprivation, triggering FAP proliferation and differentiation into endothelial cells in vitro and in vivo. In response to glucose deprivation, FAPs down regulate fibrotic and fat associated genes and acquire an endothelial cell fate, which is dependent upon mTORC2-HIF2a-eNOS pathway. These findings bring new insights into the mechanisms of vascular regeneration during muscle regeneration and define a highly plastic resident progenitor population that responds to oxygen/glucose-deprivation induced cell stress by promoting an endothelial cell fate.


2021 ◽  
pp. 1-23
Author(s):  
Theret Marine ◽  
Saclier Marielle ◽  
Messina Graziella ◽  
Rossi M.V. Fabio

While skeletal muscle remodeling happens throughout life, diseases that result in its dysfunction are accountable for many deaths. Indeed, skeletal muscle is exceptionally capable to respond to stimuli modifying its homeostasis, such as in atrophy, hypertrophy, regeneration and repair. In particular conditions such as genetic diseases (muscular dystrophies), skeletal muscle’s capacity to remodel is strongly affected and undergoes continuous cycles of chronic damage. This induces scarring, fatty infiltration, as well as loss of contractibility and of the ability to generate force. In this context, inflammation, primarily mediated by macrophages, plays a central pathogenic role. Macrophages contribute as the primary regulators of inflammation during skeletal muscle regeneration, affecting tissue-resident cells such as myogenic cells and endothelial cells, but also fibro-adipogenic progenitors, which are the main source of the fibro fatty scar. During skeletal muscle regeneration their function is tightly orchestrated, while in dystrophies their fate is strongly disturbed, resulting in chronic inflammation. In this review, we will discuss the latest findings on the role of macrophages in skeletal muscle diseases, and how they are regulated.


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