Calcium Homeostasis and Muscle Energy Metabolism Are Modified in HspB1-Null Mice

Abstract

Hsp27—encoded by HspB1—is a member of the small heat shock proteins (sHsp, 12–43 kDa (kilodalton)) family. This protein is constitutively present in a wide variety of tissues and in many cell lines. The abundance of Hsp27 is highest in skeletal muscle, indicating a crucial role for muscle physiology. The protein identified as a beef tenderness biomarker was found at a crucial hub in a functional network involved in beef tenderness. The aim of this study was to analyze the proteins impacted by the targeted invalidation of HspB1 in the Tibialis anterior muscle of the mouse. Comparative proteomics using two-dimensional gel electrophoresis revealed 22 spots that were differentially abundant between HspB1-null mice and their controls that could be identified by mass spectrometry. Eighteen spots were more abundant in the muscle of the mutant mice, and four were less abundant. The proteins impacted by the absence of Hsp27 belonged mainly to calcium homeostasis (Srl and Calsq1), contraction (TnnT3), energy metabolism (Tpi1, Mdh1, PdhB, Ckm, Pygm, ApoA1) and the Hsp proteins family (HspA9). These data suggest a crucial role for these proteins in meat tenderization. The information gained by this study could also be helpful to predict the side effects of Hsp27 depletion in muscle development and pathologies linked to small Hsps.

The Invalidation of HspB1 Gene in Mouse Alters the Ultrastructural Phenotype of Muscles

“…Compensation which may be elicited by other small Hsps has probably occurred during early development and postnatal life. Consistently we previously reported changes in the status of sHsps in the muscles of the HspB1 -/- mouse [ 36 , 37 ] that may support functional redundancy. However we report here specific characteristics of the HspB1 -/- mouse: a gender dimorphism with marked effects in males, an effect on body weight with no obvious changes in the growth rate, a lower plasma lipids profile, and an alteration of muscle ultrastructure.…”

“…However, as we examined animals only postnatally we cannot exclude that the muscles of the mutant mouse could have developed slower than those of wild-type during foetal development. Interestingly, very specific differences between mutants and wild-type controls were detected at the protein level [ 37 ]. The electrophoretic profiles of m. Soleus proteins showed differences in myofibrillar proteins, especially the presence of a putative developmental MyHC isoform which remains to be confirmed.…”

Beef tenderness and intramuscular fat proteomic biomarkers: muscle type effect

“…Following the procedure used by ( Gagaoua et al, 2015b ), a correlation between biomarkers (strength and sign) was considered robust if it existed at the same time and in the same direction for each of the five muscles. Networks describing cellular processes of the conversion of muscle into meat are very scarce ( Gagaoua et al, 2015b ; Picard et al, 2016 ). Thus, the interpretation of the consistent correlations ( Fig.…”

“…An earlier study by our group showed that it is at a crucial hub in a functional network involved in beef tenderness ( Guillemin et al, 2011a ). In HspB1 -null mice, comparative proteomics in Tibialis anterior muscle comparatively to the littermate controls showed that the proteins impacted by the absence of HSP27 belong mainly to calcium homeostasis (DRL and CALSQ1), contraction (TnnT3), energy metabolism (TPI1, MDH1, PDHB, CKM, PYGM and APOA1) and Hsp proteins family (HspA9) ( Picard et al, 2016 ). The negative correlation observed in the present study between HSP27 and slow oxidative proteins such as TNNT1, is in accordance with the data of these authors ( Table S1 ).…”

Effect of sex and RYR1 gene mutation on the muscle proteomic profile and main physiological biomarkers in pigs at slaughter

“…In our study we could not quantify changes in the 469 abundance of muscle proteins involved in calcium homeostasis, such as sarcalumenin or 470 calsequestrin-1, that were not separated in the 1D SDS-PAGE gels. These proteins have 471 recently been detected by 2D-electrophoresis in mice muscle by Picard et al (2016) 472 who found that its abundance in the Tibialis anterior muscle (fast glycolytic) increased 473 in the absence of Hsp27 (heat shock protein that has been described as beef tenderness 474 biomarker, by the group of Picard).…”