All skeletal bones house osteogenic stem cell niches, in which mesenchymal stromal cells (MSC) provide progenitors for tissue growth and regeneration. They have been widely studied in long bones formed through endochondral ossification. Limited information is available on the composition of the osteogenic niche in flat bones (i.e., skull vault bones) that develop through direct membranous ossification. Craniosynostosis (CS) is a congenital craniofacial defect due to the excessive and premature ossification of skull vault sutures. This study aimed at analysing the expression of GLI1, AXIN2 and THY1 in the context of the human skull vault, using nonsyndromic forms of CS (NCS) as a model to test their functional implication in the aberrant osteogenic process. The expression of selected markers was studied in NCS patients’ calvarial bone specimens, to assess the in vivo location of cells, and in MSC isolated thereof. The marker expression profile was analysed during in vitro osteogenic differentiation to validate the functional implication. Our results show that GLI1 and AXIN2 are expressed in periosteal and endosteal locations within the osteogenic niche of human calvarial bones. Their expression is higher in MSC isolated from calvarial bones than in those isolated from long bones and tends to decrease upon osteogenic commitment and differentiation. In particular, AXIN2 expression was lower in cells isolated from prematurely fused sutures than in those derived from patent sutures of NCS patients. This suggests that AXIN2 could reasonably represent a marker for the stem cell population that undergoes depletion during the premature ossification process occurring in CS.

Childhood ependymomas are heterogenous chemoresistant neoplasms arising from aberrant stem-like cells. Epigenome deregulation plays a pivotal role in ependymoma pathogenesis, suggesting that epigenetic modifiers hold therapeutic promise against this disease. Bromodomain and extraterminal domain (BET) proteins are epigenome readers of acetylated signals in histones and coactivators for oncogenic and stemness-related transcriptional networks, including MYC/MYCN (Proto-Oncogene, BHLH Transcritpion Factor)-regulated genes. We explored BET inhibition as an anticancer strategy in a panel of pediatric patient-derived ependymoma stem cell models by OTX015-mediated suppression of BET/acetylated histone binding. We found that ependymoma tissues and lines express BET proteins and their targets MYC and MYCN. In vitro, OTX015 reduced cell proliferation by inducing G0/G1-phase accumulation and apoptosis at clinically tolerable doses. Mechanistically, inhibitory p21 and p27 increased in a p53-independent manner, whereas the proliferative driver, phospho-signal transducer and activator of transcription 3 (STAT3), decreased. Upregulation of apoptosis-related proteins and survivin downregulation were correlated with cell line drug sensitivity. Minor alterations of MYC/MYCN expression were reported. In vivo, OTX015 significantly improved survival in 2/3 orthotopic ependymoma models. BET proteins represent promising targets for pharmaceutical intervention with OTX015 against ependymoma. The identification of predictive determinants of sensitivity may help identify ependymoma molecular subsets more likely to benefit from BET inhibitor therapies.

This narrative review highlights the latest achievements in the field of post-surgical rehabilitation of posterior fossa tumors. Studies investigating the effects of cognitive rehabilitation programs have been considered, following a comprehensive literature search in the scientific electronic databases: Pubmed, Scopus, Plos One, and ScienceDirect. This review investigates the effects of cognitive remediation, with specific highlights for single cognitive domains. The results revealed that in spite of the increasing number of children who survive into adulthood, very few studies investigated the effects of rehabilitation programs in this specific population. This study details new, promising therapeutic opportunities for children after brain surgery. More research in this filed is needed to identify the most effective protocols for clinical use.

Craniosynostosis (CS) is the second most prevalent craniofacial congenital malformation due to the premature fusion of skull sutures. CS care requires surgical treatment of variable complexity, aimed at resolving functional and cosmetic defects resulting from the skull growth constrain. Despite significant innovation in the management of CS, morbidity and mortality still exist. Residual cranial defects represent a potential complication and needdedicated management to drive a targeted bone regeneration while modulating suture ossification. To this aim, existing techniques are rapidly evolving and include the implementation of novel biomaterials, 3D printing and additive manufacturing techniques, and advanced therapies based on tissue engineering. This review aims at providing an exhaustive and up-to-date overview of the strategies in use to correct these congenital defects, focusing on the technological advances in the fields of biomaterials and tissue engineering implemented in pediatric surgical skull reconstruction, i.e., biodegradable bone fixation systems, biomimetic scaffolds, drug delivery systems, and cell-based approaches.