, UMR1213 Herbivores, INRA

. Cassar-malek, There is increasing evidence to substantiate Hsp27 as biomarker in many disease states including renal injury, cancer, cardiovascular disease, and neuro-degenerative disease. Abundance of Hsp27 is the highest in skeletal muscle indicating a crucial role for muscle physiology. In the context of a research program dedicated to phenotyping of mouse models, we generated an HspB1-null mouse. The mutant mouse is viable, fertile and shows neither apparent morphological, anatomical alterations nor changes in the macroscopic muscle phenotype. However, abnormalities in the myofibrillar structure and ultrastructure of mutant mice have been observed by electron microscopy, Hsp27-encoded by HspB1-is a member of the small heat shock proteins (sHsp, pp.12-43, 2013.

, Comparative proteomics revealed 22 2-DE spots differentially abundant between HspB1-null mice (n=5) and their controls (n=5) that could be identified by mass spectrometry. Eighteen spots were more abundant in the muscle of the mutant mice and 4 were less abundant. Gene ontology analysis indicated that 60% of proteins were intracellular proteins and 40% were plasma membrane proteins. The biological processes the most represented are the metabolic process (27%), cellular process (11%) system process (11%), The aim of this study was to analyse the proteins impacted by HspB1 targeted invalidation in the m. Tibialis anterior and to reveal interactors of Hsp27

, The information gained by this study will be helpful to predict the side-effect consequences of Hsp27 depletion in muscle development and in cancer or inflammatory pathologies linked to small Hsps, The proteins impacted by Hsp27 invalidation belonged mainly to the Hsps family (HspA8, HspA9), apoptotic pathway (Park7), and calcium homeostasis (Sarcalumenin)

. Hsp27 and . Hsp,


B. Picard, ;. , and K. Vonnahme, Didier Viala (3), Muriel Bonnet

. Umr1213-herbivores, Department of Animal Sciences

. Picard, Among the environmental factors affecting myogenesis the maternal nutrition is important. However, there are few studies about its effects on muscle properties in cattle. We investigated the effects of nutrient restriction and realimentation from early to mid-gestation on myogenesis and adipogenesis. On day 30 of pregnancy, multiparous, non-lactating cows were fed at requirement or restricted, France In cattle fetuses, myogenesis has been well documented, 2010.

. Picard, In the aim to identify proteins that may have contributed to these perturbations we applied a proteomic analysis (two dimensional electrophoresis/mass spectrometry). 28 muscular proteins had abundances modified (P>0.10) by maternal nutrition in 140 days old fetuses. They are mainly involved in glycolysis, tricarboxylic acid cycle, cellular protein metabolic process, and negative regulation of apoptosis. Proteins never reported in muscle, CCT6A, VBP1, UBE2N? were proposed as central proteins for the myogenesis by a bioinformatic study performed with our recently developed webservice ProteINSIDE, 2015.

, myogenesis, foetal programming, proteomics, bioinformatics Skeletal muscle development-#3232

, Dissection of the genome-wide transcriptional synergy between Six and Myod during myogenic commitment and differentiation Maire Pascal, pp.23-356

I. Cochin, INSERM

, Using microarray experiments, we find 761 genes under the synergistic control of both Six and Myod. Using Myod ChIPseq data along with a genome-wide search for the Six1/4 MEF3 binding sites, we find a significant co-localization of Myod and Six binding on 1,230 1kbp-long Mouse genomic DNA regions. The combination of both datasets yields a set of 82 genes whose expression was synergistically activated by Six+Myod with 96 associated Myod+MEF3 putative enhancers. We tested 19 of these enhancers by luciferase assays and found that 14 of them (74%) reproduced the synergistic behavior of the nearest gene at the reporter level. Finally, we conducted a hybrid binding site analysis on these enhancers using a de novo search and binding motifs in available databases. We found 15 overrepresented motifs, including known (MEF2, AP1, MEIS1) and new ones. Extensive mutagenesis on two enhancers shows that several of these motifs participate to the Six+Myod transcriptional synergy. Corresponding nuclear proteins were as well found enriched in cells under the control of Six and Myod. Altogether, these results provide an unprecedented regulatory dissection of genetic MEF reprogramming to a myogenic fate, Myogenic regulatory factors of the Myod family are bHLH transcription factors that have the ability to engage pluripotent embryonic cells in the myogenic lineage, and to reprogram differentiated cells to a myogenic fate

, Myod Six reprogramming Skeletal muscle development-#3253

F. Ruggiero, Slow muscle precursors lay down a matrix COLXV-B fingerprint to guide motor axon navigation Emilie Guillon (1), Sandrine Bretaud, issue.1, pp.23-357

E. Igfl, -. De-lyon, and L. , France The extracellular matrix (ECM) provides local positional information to guide motoneuron axons towards their muscle target

, We further demonstrate that collagen XV-B deposition is both temporally and spatially regulated prior to motor axon extension from the spinal cord in such a way that it remains in this region after the adaxial cells have migrated towards the periphery of the myotome. Loss and gain of function experiments in zebrafish embryos demonstrate that col15a1b expression and subsequent collagen XV-B deposition and organization in the motor path ECM depend on a previously undescribed two-step mechanism involving Hedgehog/Gli and unplugged/MuSK signaling pathways. In silico analysis predicts a putative Gli binding site in the col15a1b proximal promoter. Using col15a1b promoter-reporter constructs, we demonstrate that col15a1b participates in the slow muscle genetic program as a direct target of Hedgehog/Gli signaling.Col15a1b knockdown or overexpression provokes pathfinding errors in primary and secondary motoneuron axons both at and beyond the choice point where axon pathway selection takes place. These defects result in muscle atrophy and compromised swimming behavior, a phenotype partially rescued by injection of a smyhc1:col15a1b construct. These reveal an unexpected and novel role for COLXV-B in motor axon pathfinding and neuromuscular development. extracellular matrix, Collagen XV is a basement membrane component mainly expressed in skeletal muscle. We have identified twozebrafish collagen XV gene paralogs, col15a1a and col15a1b thatdisplay distinct expression patterns

M. Pascal, Sine oculis homeobox (Six) genes and muscle stem cell environment Maud WURMSER (1), Josiane DEMIGNON, issue.1, pp.23-358

. Institut-cochin, Sine oculis homeobox (Six) genes encodes for transcription factors that are essential for muscle development. We observed that in the absence of Six1 and Six4 proteins, muscle stem cells did not locate correctly in their niche at the end of the fetal life. Upon engraftment in an injured adult muscle, those fetal cells poorly regenerated the host muscle, only forming immature myofibers. We are trying to understand the role of Six homeoproteins in the establishment of the skeletal muscle stem cell niche, with in vivo and in vitro models of myogenic stem cells homing, The environment in which stem cells behave all along their life allow them to retain their stemness properties and to renew their host tissue, p.2323

, P24-359-Pharmacologically-induced mouse model of adult spinal muscular atrophy to evaluate effectiveness of therapeutics after disease onset

Z. Feng, ;. Karen, K. Y. Ling-;-xin-zhao, ;. , G. Karp-;-ellen et al., Sergey Paushkin (5)

, Biological Sciences

N. Therapeutics and . Inc,

N. Therapeutics and . Inc,

N. Sma-foundation, Etats-Unis Spinal muscular atrophy (SMA) is a genetic disease characterized by atrophy of muscle and loss of spinal motor neurons. SMA is caused by deletion or mutation of the survival of motor neuron 1 (SMN1) gene and the nearly identical SMN2 gene fails to generate adequate levels of functional SMN protein due to a splicing defect