SummaryThe RNA-binding protein HuD promotes neurogenesis and favors recovery from peripheral axon injury. HuD interacts with many mRNAs, altering both stability and translation efficiency. We generated a nucleotide resolution map of the HuD RNA interactome in motor neuron-like cells, identifying HuD target sites in 1,304 mRNAs, almost exclusively in the 3′ UTR. HuD binds many mRNAs encoding mTORC1-responsive ribosomal proteins and translation factors. Altered HuD expression correlates with the translation efficiency of these mRNAs and overall protein synthesis, in a mTORC1-independent fashion. The predominant HuD target is the abundant, small non-coding RNA Y3, amounting to 70% of the HuD interaction signal. Y3 functions as a molecular sponge for HuD, dynamically limiting its recruitment to polysomes and its activity as a translation and neuron differentiation enhancer. These findings uncover an alternative route to the mTORC1 pathway for translational control in motor neurons that is tunable by a small non-coding RNA.

SummaryScientific background: Platelet concentrates are nowadays widely applied in different clinical fields to improve soft tissue and bone regeneration. "Concentrated Growth Factors" (CGF) is a new generation of platelet concentrate products, which exhibits an interesting clinical and biotechnological application potential. Aim of the study:The aim of this study is to assess the biological rationale for the use of CGF, by evaluating blood cell localization, the in vitro cumulative release of seven growth factors (PDGF-AB, VEGF, TNF-α, TGF-β1, BDNF, BMP-2 and IGF-1), its in vitro effects on cell proliferation and its mechanical behavior.Methods: CGFs were obtained from volunteer donors. Blood cell localization was evaluated after properly morphological staining and immunohistochemistry. The amount of growth factors release was measured at 5 hours, 1, 3, 6, 7 and 8 days, using ELISA assay. Cells were cultured with and without CGF and their proliferation was evaluated after 72 hours, performing the quantification of Ki-67, using flow cytometry (FACS). The mechanical response of CGF under compression was also attempted. Results:The results showed that platelets and leukocytes were found in a very thin space called "buffy coat", localized between the white and red part of CGF. Each growth factor evaluated, had a specific kinetic release with a great variability among subjects. The in vitro cell proliferation was stimulated. CGF showed an "apparent plasticity" and its mechanical response was influenced by fibrin network structure. Conclusion:These findings support the CGF's clinical use and will allow us to better understand and improve the clinical outcomes. B io lo g y and M e d ic in e

Bisphosphonates are primary pharmacological agents against osteoclast-mediated bone loss and widely used in the clinical practice for prevention and treatment of a variety of skeletal conditions, such as low bone density and osteogenesis imperfecta, and pathologies, such as osteoporosis, malignancies metastatic to bone, Paget disease of bone, multiple myeloma, and hypercalcemia of malignancy. However, long-term bisphosphonate treatment is associated with pathologic conditions including osteonecrosis of the jaw, named BRONJ, which impaired bone regeneration process. Clinical management of BRONJ is controversy and one recent approach is the use of platelet concentrates, such as Concentrated Growth Factors, alone or together with biomaterials or antioxidants molecules, such as resveratrol. The aim of the present study was to investigate the in vitro effects of Concentrated Growth Factors and/or resveratrol on the proliferation and differentiation of human osteoblasts, treated or not with bisphosphonates. Human osteoblasts were stimulated for 3 days in complete medium and for 21 days in mineralization medium. At the end of the experimental period, the in vitro effect on osteoblast proliferation and differentiation was evaluated using different techniques such as MTT, ELISA for the quantification/detection of osteoprotegerin and bone morphogenetic protein-2, immunohistochemistry for sirtuin 1 and collagen type I, and the Alizarin Red S staining for the rate of mineralization. Results obtained showed that Concentrated Growth Factors and/or resveratrol significantly increased osteoblast proliferation and differentiation and that the cotreatment with Concentrated Growth Factors and resveratrol had a protective role on osteoblasts treated with bisphosphonates. In conclusion, these data suggest that this approach could be promised in the clinical management of BRONJ.

Platelet concentrates, such as Concentrated Growth Factors (CGF), are autologous preparations obtained from the patient's own blood and rich in platelets, growth factors and cytokines involved in the key processes of tissue regeneration. These autologous concentrates differ in the way of preparation and also in the content of platelets, growth factors and leucocytes, as well as in the fibrin network architecture. So it is difficult to have a standardized product. The aim of the present study was to evaluate how the use of test tubes of different material, for blood collection, could influence the CGF production. Three different test tubes were used and the obtained CGFs were subjected to histomorphological and immunohistochemical analyses. Results showed that the tube material and shape influenced the CGF composition. In fact, according to the type of tube used, the obtained CGFs showed differences in morphology, in the fibrin network architecture and in blood cell localization and distribution.

The aim of this study was to investigate the in vitro effect of Silicon, in the soluble form of sodium orthosilicate, combined and not with the concentrated growth factors (CGF), a platelet-rich preparation, on three different human cell lines of fibroblasts (NHDF), endothelial cells (HUVEC), and osteoblasts (HOBs). Each cell type was treated with sodium orthosilicate at the final concentration of 0.5 mM and 1 mM, CGF, and sodium orthosilicate combined with CGF, for 72 h. At the end of the experimental period, the in vitro effect on cell growth, proliferation, and metabolic activity was evaluated by performing a simple cell count, using an automated cell counter and by evaluating the expression of the intracellular proliferation marker Ki-67, using Fluorescence-activated cell sorting (FACS) analysis. Moreover, the expression of other cell markers and active molecules, such as Collagen type I, Osteopontin, Vascular Endothelial Growth Factor, and endothelial Nitric Oxide Synthase, was evaluated, through immunohistochemistry. Results obtained showed that the combined use of CGF and sodium orthosilicate stimulates cell growth, proliferation, and metabolic activity, suggesting that this treatment could be effective in tissue regeneration.