Genes and miRNAs as Hurdles and Promoters of Corticospinal Tract Regeneration in Spinal Cord Injury

Spinal cord injury (SCI) is a devastating lesion to the spinal cord, which determines the interruption of ascending/descending axonal tracts, the loss of supraspinal control of sensory-motor functions below the injured site, and severe autonomic dysfunctions, dramatically impacting the quality of life of the patients. After the acute inflammatory phase, the progressive formation of the astrocytic glial scar characterizes the acute-chronic phase: such scar represents one of the main obstacles to the axonal regeneration that, as known, is very limited in the central nervous system (CNS). Unfortunately, a cure for SCI is still lacking: the current clinical approaches are mainly based on early vertebral column stabilization, anti-inflammatory drug administration, and rehabilitation programs. However, new experimental therapeutic strategies are under investigation, one of which is to stimulate axonal regrowth and bypass the glial scar. One major issue in axonal regrowth consists of the different genetic programs, which characterize axonal development and maturation. Here, we will review the main hurdles that in adulthood limit axonal regeneration after SCI, describing the key genes, transcription factors, and miRNAs involved in these processes (seen their reciprocal influencing action), with particular attention to corticospinal motor neurons located in the sensory-motor cortex and subjected to axotomy in case of SCI. We will highlight the functional complexity of the neural regeneration programs. We will also discuss if specific axon growth programs, that undergo a physiological downregulation during CNS development, could be reactivated after a spinal cord trauma to sustain regrowth, representing a new potential therapeutic approach

Chitosan-based hydrogel to support the paracrine activity of mesenchymal stem cells in spinal cord injury treatment

Abstract Advanced therapies which combine cells with biomaterial-based carriers are recognized as an emerging and powerful method to treat challenging diseases, such as spinal cord injury (SCI). By enhancing transplanted cell survival and grafting, biomimetic hydrogels can be properly engineered to encapsulate cells and locate them at the injured site in a minimally invasive way. In this work, chitosan (CS) based hydrogels were developed to host mesenchymal stem cells (MSCs), since their paracrine action can therapeutically enhance the SC regeneration, limiting the formation of a glial scar and reducing cell death at the injured site. An injectable and highly permeable CS-based hydrogel was fabricated having a rapid gelation upon temperature increase from 0 to 37 °C. CS was selected as former material both for its high biocompatibility that guarantees the proper environment for MSCs survival and for its ability to provide anti-inflammatory and anti-oxidant cues. MSCs were mixed with the hydrogel solution prior to gelation. MSC viability was not affected by the CS hydrogel and encapsulated MSCs were able to release MSC-vesicles as well as to maintain their anti-oxidant features. Finally, preliminary in vivo tests on SCI mice revealed good handling of the CS solution loading MSCs during implantation and high encapsulated MSCs survival after 7 days

Mesenchymal Stem Cells for Spinal Cord Injury: Current Options, Limitations, and Future of Cell Therapy

Spinal cord injury (SCI) constitutes an inestimable public health issue. The most crucial phase in the pathophysiological process of SCI concerns the well-known secondary injury, which is the uncontrolled and destructive cascade occurring later with aberrant molecular signaling, inflammation, vascular changes, and secondary cellular dysfunctions. The use of mesenchymal stem cells (MSCs) represents one of the most important and promising tested strategies. Their appeal, among the other sources and types of stem cells, increased because of their ease of isolation/preservation and their properties. Nevertheless, encouraging promise from preclinical studies was followed by weak and conflicting results in clinical trials. In this review, the therapeutic role of MSCs is discussed, together with their properties, application, limitations, and future perspectives

Pharmacological c-Jun NH2-Terminal Kinase (JNK) Pathway Inhibition Reduces Severity of Spinal Muscular Atrophy Disease in Mice

Spinal muscular atrophy (SMA) is a severe neurodegenerative disorder that occurs in early childhood. The disease is caused by the deletion/mutation of the survival motor neuron 1 (SMN1) gene resulting in progressive skeletal muscle atrophy and paralysis, due to the degeneration of spinal motor neurons (MNs). Currently, the cellular and molecular mechanisms underlying MN death are only partly known, although recently it has been shown that the c-Jun NH2-terminal kinase (JNK)-signaling pathway might be involved in the SMA pathogenesis. After confirming the activation of JNK in our SMA mouse model (SMN2+/+; SMN\u3947+/+; Smn-/-), we tested a specific JNK-inhibitor peptide (D-JNKI1) on these mice, by chronic administration from postnatal day 1 to 10, and histologically analyzed the spinal cord and quadriceps muscle at age P12. We observed that D-JNKI1 administration delayed MN death and decreased inflammation in spinal cord. Moreover, the inhibition of JNK pathway improved the trophism of SMA muscular fibers and the size of the neuromuscular junctions (NMJs), leading to an ameliorated innervation of the muscles that resulted in improved motor performances and hind-limb muscular tone. Finally, D-JNKI1 treatment slightly, but significantly increased lifespan in SMA mice. Thus, our results identify JNK as a promising target to reduce MN cell death and progressive skeletal muscle atrophy, providing insight into the role of JNK-pathway for developing alternative pharmacological strategies for the treatment of SMA

Molecular diversity within clones of cv. Tannat (Vitis vinifera)

DNAs from 9 clones of cv. Tannat (Vitis vinifera) were analyzed at 89 microsatellite loci. Only one, VMCNg 1d12, showed a differential pattern that separated the clones in two groups. The statistical analysis of concentrations for aroma compounds from microvinifications also resulted in the same two groupings of clones. Many analyzed microsatellite loci amplified only one allele, implying that Tannat is a highly homozygous variety. For a given set of 15 microsatellites the level of homozygosity was 53 % for Tannat, in contrast to 6 % for Pinot, 20 % for both Cabernet Franc and Chardonnay and 33 % for Cabernet Sauvignon. We provide molecular data for Tannat, originating from southwestern France and nowadays becoming the emblematic cultivar of Uruguayan fine red wines. We also report a correlation between aroma-related compounds and molecular markers within clones of a cultivar.

Synthesis and CNS activities of pyridopyrazinone and pyridodiazepinone derivatives

New tricyclic derivatives with cyclocondensed pyrido-pyrazine 7,10 and pyrido-diazepine 20a,20b skeletons were synthetized and biologically investigated. The compounds, preliminarily tested on explorative, muscle relaxing, antinociceptive, spontaneous motor activities and influence on the narcotic effect of Evipan, revealed interesting CNS depressant and analgesic activities. The pyrido[2,3-e]pyrrolo[1,2-a]pyrazine structure of 7 appeared the most promising for analgesic and neuroleptic activities. The above compounds were assayed also for their capacity to inhibit DNA synthesis in Ehrlich ascites tumor cells; 20a appeared to be able of inducing a significant inhibition