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Sam68 ensures the establishment of neuromuscular junctions (NMJs) and motor unit integrity by orchestrating a neuronal splicing program., RNA-binding proteins orchestrate the composite life of RNA molecules and impact most physiological processes, thus underlying complex phenotypes. The RNA-binding protein Sam68 regulates differentiation processes by modulating splicing, polyadenylation, and stability of select transcripts. Herein, we found that Sam68−/− mice display altered regulation of alternative splicing in the spinal cord of key target genes involved in synaptic functions. Analysis of the motor units revealed that Sam68 ablation impairs the establishment of neuromuscular junctions and causes progressive loss of motor neurons in the spinal cord. Importantly, alterations of neuromuscular junction morphology and properties in Sam68−/− mice correlate with defects in muscle and motor unit integrity. Sam68−/− muscles display defects in postnatal development, with manifest signs of atrophy. Furthermore, fast-twitch muscles in Sam68−/− mice show structural features typical of slow-twitch muscles, suggesting alterations in the metabolic and functional properties of myofibers. Collectively, our data identify a key role for Sam68 in muscle development and suggest that proper establishment of motor units requires timely expression of synaptic splice variants.

During aging, multifactorial events such as activation of inflammatory pathways and mitochondrial dysfunction lead to the onset of sarcopenia, which is characterized by a gradual loss of muscle protein component. It is well known that changes in the quantity and the quality of dietary proteins, as well as the intake of specific amino acids or antioxidants supplementation, counteract some physiopathological processes related to the progression of the loss of muscle mass and may have beneficial effects in improving the anabolic response of muscle in the elderly. The aim of this research is to delay and hopefully prevent, in a mouse experimental model, the loss of muscle mass and functional capacity of aged muscle by dietary supplementation of micronutrients intake. To this purpose we evaluated whether a protein diet rich in arginine and/or taurine, already known to down-regulate the release of inflammatory cytokines in dystrophic muscles (1, 2), modulates the activation of catabolic processes leading to loss of muscle mass characteristic of aged muscle. To this purpose, adult mice were subjected to intraperitoneal injections of taurine, arginine or both, all days for 2 months. The tibialis anterior muscles (TA) were then damaged by cardiotoxin injection. Our results demonstrate that injured TA muscles of mice which received both aminoacids show enhanced regeneration response as demonstrated by the presence of central nucleated fibers, less amount of inflammatory cells and fibrosis, if compared to the control. Moreover the high expression of the inflammation marker, NF-kB, in injured muscle of control mice strongly decreases in taurine + arginine injected mice. These results suggest a role of taurine and arginine in the down-regulation of inflammation and the enhancement of regeneration in skeletal muscle., Italian Journal of Anatomy and Embryology, Vol. 120, No. 1 (Supplement) 2015

Reelin is a large secreted extracellular glycoprotein that plays a critical role in the regulation of neuronal migration during brain development. Reelin is thought to guide migrating neurons by interacting with cell surface receptors, very low density lipoprotein receptor (VLDLR), apolipoprotein E receptor 2 (ApoER2), and a3 b1integrin, inducing tyrosine phosphorylation of the intracellular adapter protein Disabled-1 (Dab-1) that instructs neurons to reach their correct laminar position in the cortex. Recent evidence supports a role of Reelin in the control of cell proliferation through the activation of mitogen protein kinase (ERK) pathway. We have previously shown, by immunohistochemistry and stereological analysis, the expression of Reelin in both Glioblastoma (GBM) and in peritumor tissue. Moreover, we reported the expression of Reelin in cancer stem cells isolated from both tumor (GCSC) and peritumor tissue (PCSC), suggesting that this protein might contribute to neurosphere formation. Here we investigated by both Real-Time Polymerase Chain Reaction (RT-PCR) and Western Blotting (WB) analysis the gene and protein expression of Reelin and its intracellular adapter Dab-1 in GCSC and PCSC derived from four different patients. Analysis of gene and protein expression indicates higher level of Reelin and DAB-1 in PCSC compared to GCSC. These data suggest a possible role for Reelin and Dab-1 in the control of cell migration and GBM invasiveness., Italian Journal of Anatomy and Embryology, Vol. 120, No. 1 (Supplement) 2015

The Toll-like Receptor (TLR) family ensures prompt response towards pathogens, protecting the host against infections, and guarantees a realistic balance between protective and detrimental activities. Multiple regulating mechanisms characterize TLR activity that is not limited to innate and adaptive antimicrobial immune responses, as observed in the inflammatory (either infective, allergic, or autoimmune) responses associated with tissue remodeling. Following the insult and the arise of inflammatory response, tissue remodeling takes place and might develop in fibrosis, depending on microenvironment as a result of imbalanced fibroblasts (FBs) and myofibroblasts (myoFBs) activation/survival. The process is driven by an epithelial-fibroblast-immune cell cross-talk. While the main FB function is the matrix metabolism for tissue homeostasis or repair, the myoFB differentiation represents a crucial step in attempting repair of injury. FBs/myoFBs provide more than structural support at site of injury, synthesizing and/or reacting to different cytokines, growth factors, neuromediators and soluble/lipid mediators. TLR-bearing FBs/myoFBs might contribute at the innate immune level, providing a second line of protection/defense as well as being a target/effector cell of tissue remodeling. TLRs might also interfere with acute inflammation as well as with established fibrosis, triggering structural/functional changes in agreement with the genetic background, the site of lesion, the entity of associated infection, the poor blood circulation or the pharmacological treatments, all together strictly influencing tissue repair/remodeling process. This review will focus on the recent findings on TLRs at launch and long-lasting tissue remodeling process, that strongly suggest TLRs as optional targets for future therapies.

The mechanisms responsible for resistance to damage in normal cells might determine chemoresistance in both tumor cells and cancer stem cells (CSC). Relapse due to chemoresistant residual disease is a major cause of death in GBM. Increasing body of evidence indicates that not only tumor area (TT), but also tissue surrounding the tumor border (pTT) of GBM contains tumor cells and CSC, which could contribute to the disease progression. Therefore, the need to have a deeper insight in this area through identification of the characteristics that confer chemoresistance. In this study, the expression of molecules involved in chemoresistance was investigated in samples derived from TT and from pTT at, Italian Journal of Anatomy and Embryology, Vol 118, No 2 (Supplement) 2013

It is becoming increasingly clear that tumour development is due to a small fraction of mutated stem cells (CSC). Established cancer cell lines represent a good source of CSC with respect to tissue tumour samples because they do not contain any contaminating normal stem cells and it is easy to obtain large quantities of them. We isolated putative CSC via a non-adherent neurosphere (NS) assay from LI. Using a clonal assay, we selected from the primary NS two clones named F11 and D2. LI, F11 and D2 cells and these clones under differentiation were examined for expression of stem cell markers (CD133, Nestin, Musashi-1 and Sox-2), markers of differentiation (βIII-Tubulin and GFAP) and Ca2+-channels, by immunocytochemistry, western blot analysis and confocal Ca2+ imaging. Both F11 and D2 clones expressed higher levels of stem cell markers with respect to LI cells. Markers of differentiation were expressed at high levels in both LI cells and clones. The expression of Nestin, Sox-2, and βIII-Tubulin was down-regulated in clones under differentiation, whereas Musashi-1 was increased. LI, F11 and D2 cells did not exhibit Ca2+ signals following KCl-induced membrane depolarization, thus suggesting that they do not express functional voltage-dependent Ca2+-channels. Nevertheless, transient increases in intracellular Ca2+ levels were observed after cell exposure to ATP in both F11 and D2 during differentiation. The ATP treatment did not affect cell proliferation. The increased expression of stem cell markers and their decrease in cells under differentiation demonstrate the stem characteristics of clones we selected. The findings regarding expression of differentiation markers and of Ca2+-channels require further investigation. After a deeper characterization, both F11 and D2 could represent a good model to improve the knowledge on CSC and to identify new therapeutic approaches in GBM., Italian Journal of Anatomy and Embryology, Vol 117, No 2 (Supplement) 2012