FARP1 Promotes the Dendritic Growth of Spinal Motor Neuron Subtypes through Transmembrane Semaphorin6A and PlexinA4 Signaling

SummaryThe dendritic morphology of neurons dictates their abilities to process and transmit information; however, the signaling pathways that regulate dendritic growth and complexity are poorly understood. Here, we show that retinoids induce the expression of the FERM Rho-GEF protein FARP1 in the developing spinal cord. FARP1 is expressed in subsets of motor neurons and is enriched in dendrites of lateral motor column (LMC) neurons that innervate the limb. FARP1 is necessary and sufficient to promote LMC dendritic growth but does not affect dendrite number or axonal morphology. We show that FARP1 serves as a specific effector of transmembrane Semaphorin6A and PlexinA4 signals to regulate LMC dendritic growth, and that its Rho-GEF domain is necessary for this function. These findings reveal that retinoid and Sema6A/PlexA4 signaling pathways intersect through FARP1 to control dendritic growth, and uncover the existence of subtype-specific signaling networks that control dendritic developmental programs in spinal motor neurons

Endovascular therapies for malignant gliomas: Challenges and the future

Malignant gliomas are very difficult tumors to treat, with few effective therapies, early progression and high rates of recurrence. Here we review the literature on malignant gliomas treated with endovascular therapy. Endovascular therapy for malignant gliomas falls into one of three categories: (1) neoadjuvant embolization and devascularization; (2) direct intra-arterial drug delivery; and (3) disruption of the blood-brain barrier for improved intra-arterial drug delivery. There is a range of therapeutic benefits based on the endovascular intervention used. Challenges remain for those who aim to treat malignant gliomas with an endovascular approach. Specifically, embolization is difficult to accomplish in the small vessels that feed into malignant gliomas, and intra-arterial chemotherapy has yet to prove itself better than traditional intravenous chemotherapy. However, there exists promise in the therapeutic potential of intra-arterial chemotherapy paired with disruption of the blood-brain barrier at tumor-specific sites, and as such, continued research to optimize this approach is expected to yield benefit for patients with malignant gliomas