Denervation of rabbit gastrocnemius and soleus muscles

Abstract

We report here, for the first time, the expression of the muscle-specific isoform of the glycolytic enzyme, enolase (EC 4.2.1.11) (b enolase), in rabbit skeletal muscles. We have analysed the fast-twitch gastrocnemius and the slow-twitch soleus muscles during normal postnatal development and following denervation. We show that, in rabbit, as already described in rodents, b enolase gene expression behaves as a good marker of the fast-twitch fibers. In soleus muscle, the b enolase transcript level is 10±20% of that found in gastrocnemius. Denervation, performed at 8 postnatal days, induces an important drop of b enolase transcript levels in both developing soleus and gastrocnemius muscles, with a 80% decrease observed 1 week after denervation in the operated muscles, as compared to the corresponding contralateral muscles. Thereafter, the b enolase transcript level continues to decrease in the fast-twitch muscle, with the b enolase subunit being detectable only in the atrophic fast-twitch fibers. In contrast, the b transcript level tends to increase in the denervated slow-twitch muscle, reaching about 50% of that in contralateral soleus, at 7 weeks after surgery. The level of b enolase transcripts still expressed after denervation seems to stabilize at the same low level in both types of inactive muscles. This suggests that the small fraction of b enolase expression which is not controlled by the nerve, or by the contractile activity imposed by it, is independent of the muscle phenotype.

Identification of O-linked N-Acetylglucosamine Proteins in Rat Skeletal Muscle Using Two-dimensional Gel Electrophoresis and Mass Spectrometry

“…Thus, myosin heavy chain, muscle creatine kinase, ␣B-crystallin, as well as glyceraldehyde-3-phosphate dehydrogenase have been reported to be four earlier markers of muscle disuse (52,53), while induction of carbonic anhydrase III (54) as well as effect on muscle specific enolase (55) have been demonstrated in muscle after denervation. This could indicate that the OGlcNAc modifications are involved in the muscle plasticity and rapid adaptation to new physiological conditions.…”

A Histone Deacetylase 4/Myogenin Positive Feedback Loop Coordinates Denervation-dependent Gene Induction and Suppression

“…muscle-specific enolase (MSE) gene for this analysis because it is robustly suppressed after muscle denervation (Nozais et al, 1999). As shown in Figure 1A, inhibition of HDAC activity with NaB resulted in increased MSE mRNA levels in differentiated C2C12 cells and the protein synthesis inhibitor cycloheximide had little effect on this induction.…”

“…Although many of the genes contributing to muscle fiber phenotype are regulated by muscle activity, not all are regulated in the same direction. For example, in the fast tibialis anterior (TA) muscle some genes, such as those encoding the MyoD family of basic helix-loop-helix transcription factors, and synaptic components such as nicotinic acetylcholine receptors (nAChRs) and muscle-specific kinase (MuSK) are induced (Goldman et al, 1985(Goldman et al, , 1986Eftimie et al, 1991;Dutton et al, 1993;, whereas other genes, such as those encoding muscle-specific enolase (MSE), phosphofructose kinase (PFK), and MHC IIb, are suppressed after muscle denervation (Huey and Bodine, 1998;Nozais et al, 1999;Tang et al, 2000;Raffaello et al, 2006). Interestingly, in contrast to denervation-dependent MHC IIb mRNA suppression in fast TA muscle (Huey and Bodine, 1998), muscle inactivity induces its expression in the slow soleus muscle (Pandorf et al, 2006), suggesting muscle fiber-type-specific regulation.…”

Proteomic changes in rat thyroarytenoid muscle induced by botulinum neurotoxin injection

“…This muscle specific glycolytic enzyme holds important roles in striated muscle development and regeneration, and is more abundant in fast-twitch muscles, such as the TA, than slow-twitch muscles [33]. Previous reports have observed downregulation of β-enolase in aged rat gastrocnemius, denervated rabbit gastrocnemius and denervated rat TA muscle [18,[33][34]. Creatine kinase, a major energy transduction enzyme and consumer of ATP, had reduced spot abundance at all post-injection time points, although it is important to note that a second protein, troponin T, was also identified in the same spot sample.…”