CRMP5 Regulates Generation and Survival of Newborn Neurons in Olfactory and Hippocampal Neurogenic Areas of the Adult Mouse Brain

The Collapsin Response Mediator Proteins (CRMPs) are highly expressed in the developing brain, and in adult brain areas that retain neurogenesis, ie: the olfactory bulb (OB) and the dentate gyrus (DG). During brain development, CRMPs are essentially involved in signaling of axon guidance and neurite outgrowth, but their functions in the adult brain remain largely unknown. CRMP5 has been initially identified as the target of auto-antibodies involved in paraneoplasic neurological diseases and further implicated in a neurite outgrowth inhibition mediated by tubulin binding. Interestingly, CRMP5 is also highly expressed in adult brain neurogenic areas where its functions have not yet been elucidated. Here we observed in both neurogenic areas of the adult mouse brain that CRMP5 was present in proliferating and post-mitotic neuroblasts, while they migrate and differentiate into mature neurons. In CRMP5−/− mice, the lack of CRMP5 resulted in a significant increase of proliferation and neurogenesis, but also in an excess of apoptotic death of granule cells in the OB and DG. These findings provide the first evidence that CRMP5 is involved in the generation and survival of newly generated neurons in areas of the adult brain with a high level of activity-dependent neuronal plasticity

The transcriptional landscape of Shh medulloblastoma

© The Author(s) 2021. Open Access. This article is licensed under a Creative Commons Attribution 4.0 International License, which permits use, sharing, adaptation, distribution and reproduction in any medium or format, as long as you give appropriate credit to the original author(s) and the source, provide a link to the Creative Commons license, and indicate if changes were made. The images or other third party material in this article are included in the article’s Creative Commons license, unless indicated otherwise in a credit line to the material. If material is not included in the article’s Creative Commons license and your intended use is not permitted by statutory regulation or exceeds the permitted use, you will need to obtain permission directly from the copyright holder. To view a copy of this license, visit http://creativecommons.org/licenses/by/4.0/.Sonic hedgehog medulloblastoma encompasses a clinically and molecularly diverse group of cancers of the developing central nervous system. Here, we use unbiased sequencing of the transcriptome across a large cohort of 250 tumors to reveal differences among molecular subtypes of the disease, and demonstrate the previously unappreciated importance of non-coding RNA transcripts. We identify alterations within the cAMP dependent pathway (GNAS, PRKAR1A) which converge on GLI2 activity and show that 18% of tumors have a genetic event that directly targets the abundance and/or stability of MYCN. Furthermore, we discover an extensive network of fusions in focally amplified regions encompassing GLI2, and several loss-of-function fusions in tumor suppressor genes PTCH1, SUFU and NCOR1. Molecular convergence on a subset of genes by nucleotide variants, copy number aberrations, and gene fusions highlight the key roles of specific pathways in the pathogenesis of Sonic hedgehog medulloblastoma and open up opportunities for therapeutic intervention.info:eu-repo/semantics/publishedVersio

TERT promoter mutations are highly recurrent in SHH subgroup medulloblastoma

Telomerase reverse transcriptase (TERT) promoter mutations were recently shown to drive telomerase activity in various cancer types, including medulloblastoma. However, the clinical and biological implications of TERT mutations in medulloblastoma have not been described. Hence, we sought to describe these mutations and their impact in a subgroup-specific manner. We analyzed the TERT promoter by direct sequencing and genotyping in 466 medulloblastomas. The mutational distributions were determined according to subgroup affiliation, demographics, and clinical, prognostic, and molecular features. Integrated genomics approaches were used to identify specific somatic copy number alterations in TERT promoter-mutated and wild-type tumors. Overall, TERT promoter mutations were identified in 21 % of medulloblastomas. Strikingly, the highest frequencies of TERT mutations were observed in SHH (83 %; 55/66) and WNT (31 %; 4/13) medulloblastomas derived from adult patients. Group 3 and Group 4 harbored this alteration in <5 % of cases and showed no association wit

Les tumeurs neuroendocrines du thymus [Thymic neuroendocrine tumors: report on 6 cases]

AIM: the aim of our study was to analyze a series of 6 thymic neuroendocrine tumors (TNET). METHODS: we report the clinical and pathological features of 6 TNET reclassified according to the last WHO classification (2004). RESULTS: there were 4 men and 2 women, (mean age of 61.3 years), presenting with local symptoms in 4 cases. The tumors were reclassified as 3 atypical carcinoids (AC), 2 small cell carcinomas (SCC) and 1 large cell neuroendocrine carcinoma (LCNEC). Cytokeratin, EMA and neuroendocrine markers were expressed in poorly-differentiated tumors. Two patients were lost of follow-up. Two patients with AC died of disease at 20 and 36 months. One patient with SCC died of disease at 2 years and the patient with the LCNEC died of disease in 3 months. CONCLUSION: TNET are poor prognosis tumors with a prognosis similar to thymic carcinomas. Adequate surgical resection is a strong prognosis facto

Surgical approach for suprasellar hemangioblastomas preserving the pituitary stalk: Review of the literature and report of a further case.

Hemangioblastomas (HBLs) are challenging vascular tumours with rare suprasellar location Surgery is recommended in patients with visual impairment, endocrine disorders or hydrocephalus. Surgical removal of pituitary stalk HBLs is challenging due to their location and high vascularity. Our narrative review was guided by the question: "what is the more suitable surgical approach to excise a suprasellar HBL?". Pertinent English literature was scrutinized from database inception to October 2016. Eighteen articles matched our selection criteria. Among the surgically treated patients, 4 were treated through a trans-sphenoidal (TS) approach, 13 through a transcranial approach (2 of them after TS failure). Five other cases were treated with radiotherapy (adjuvant in 3 cases) and 9 patients were managed with simple observation and/or medical treatment. We add a case of complete suprasellar HBL resection through an orbito-zygomatic (OZ) craniotomy with extradural anterior clinoidectomy (EAC). To achieve satisfactory oncologic results with acceptable morbidity for symptomatic suprasellar HBLs, complete tumour removal with pituitary stalk sparing should be attempted through an OZ craniotomy with EAC that provides adequate exposure of the tumour, its vascular supply and the adjacent neural structures

Two-peaked 5-ALA-induced PpIX fluorescence emission spectrum distinguishes glioblastomas from low grade gliomas and infiltrative component of glioblastomas

International audience5-ALA-induced protoporphyrin IX (PpIX) fluorescence enables to guiding in intra-operative surgical glioma resection. However at present, it has yet to be shown that this method is able to identify infiltrative component of glioma. In extracted tumor tissues we measured a two-peaked emission in low grade gliomas and in the infiltrative component of glioblastomas due to multiple photochemical states of PpIX. The second emission peak appearing at 620 nm (shifted by 14 nm from the main peak at 634 nm) limits the sensibility of current methods to measured PpIX concentration. We propose new measured parameters, by taking into consideration the two-peaked emission, to overcome these limitations in sensitivity. These parameters clearly distinguish the solid component of glioblastomas from low grade gliomas and infiltrative component of glioblastomas

5-ALA-induced PpIX fluorescence in gliomas resection: spectral complexity of the emission spectrum in the infiltrative compound

International audienc

5-ALA-induced PpIX fluorescence emission spectrum in low grade gliomas and in the infiltrative component of glioblastomas

International audienc

Liponeurocytoma of the Cerebellopontine Angle

International audienc