Julie Lerond, Bertrand Mathon, Mélina Scopin, Lucia Nichelli, Justine Guégan, Céline Bertholle, Brigitte Izac, Muriel Andrieu, Thomas Gareau, Florian Donneger, Badreddine Mohand Oumoussa, Franck Letourneur, Suzanne Tran, Mathilde Bertrand, Isabelle Le Roux, Mehdi Touat, Sophie Dupont, Jean Christophe Poncer, Vincent Navarro, Franck Bielle
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引用次数: 0
Abstract
Objective: Mesial Temporal Lobe Epilepsy-associated Hippocampal Sclerosis (MTLE-HS) is a syndrome associated with various aetiologies. We previously identified CD34-positive extravascular stellate cells (CD34+ cells) possibly related to BRAFV600E oncogenic variant in a subset of MTLE-HS. We aimed to identify the BRAFV600E oncogenic variants and characterise the CD34+ cells.
Methods: We analysed BRAFV600E oncogenic variant by digital droplet Polymerase Chain Reaction in 53 MTLE-HS samples (25 with CD34+ cells) and nine non-expansive neocortical lesions resected during epilepsy surgery (five with CD34+ cells). Ex vivo multi-electrode array recording, immunolabelling, methylation microarray and single nuclei RNAseq were performed on BRAFwildtype MTLE-HS and BRAFV600E mutant non-expansive lesion of hippocampus and/or neocortex.
Results: We identified a BRAFV600E oncogenic variant in five MTLE-HS samples with CD34+ cells (19%) and in five neocortical samples with CD34+ cells (100%). Single nuclei RNAseq of resected samples revealed two unique clusters of abnormal cells (including CD34+ cells) associated with senescence and oligodendrocyte development in both hippocampal and neocortical BRAFV600E mutant samples. The co-expression of the oncogene-induced senescence marker p16INK4A and the outer subventricular zone radial glia progenitor marker HOPX in CD34+ cells was confirmed by multiplex immunostaining. Pseudotime analysis showed that abnormal cells share a common lineage from progenitors to myelinating oligodendrocytes. Epilepsy surgery led to seizure freedom in eight of the 10 patients with BRAF mutant lesions.
Interpretation: BRAFV600E underlies a subset of MTLE-HS and epileptogenic non-expansive neocortical focal lesions. Detection of the oncogenic variant may help diagnosis and open perspectives for targeted therapies.
期刊介绍：
Neuropathology and Applied Neurobiology is an international journal for the publication of original papers, both clinical and experimental, on problems and pathological processes in neuropathology and muscle disease. Established in 1974, this reputable and well respected journal is an international journal sponsored by the British Neuropathological Society, one of the world leading societies for Neuropathology, pioneering research and scientific endeavour with a global membership base. Additionally members of the British Neuropathological Society get 50% off the cost of print colour on acceptance of their article.
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