Defining neuroblastoma: From origin to precision medicine.

Neuroblastoma (NB), a heterogenous pediatric tumor of the sympathetic nervous system, is the most common and deadly extracranial solid malignancy diagnosed in infants. Numerous efforts have been invested in understanding its origin and in development of novel curative targeted therapies. Here, we summarize the recent advances in the identification of the cell of origin and the genetic alterations occurring during development that contribute to NB.

Activation of a neural stem cell transcriptional program in parenchymal astrocytes.

Adult neural stem cells, located in discrete brain regions, generate new neurons throughout life. These stem cells are specialized astrocytes, but astrocytes in other brain regions do not generate neurons under physiological conditions. After stroke, however, striatal astrocytes undergo neurogenesis in mice, triggered by decreased Notch signaling.

Blocking Notch-Signaling Increases Neurogenesis in the Striatum after Stroke.

Stroke triggers neurogenesis in the striatum in mice, with new neurons deriving in part from the nearby subventricular zone and in part from parenchymal astrocytes. The initiation of neurogenesis by astrocytes within the striatum is triggered by reduced Notch-signaling, and blocking this signaling pathway by deletion of the gene encoding the obligate Notch coactivator Rbpj is sufficient to activate neurogenesis by striatal astrocytes in the absence of an injury. Here we report that blocking Notch-signaling in stroke increases the neurogenic response to stroke 3.

Induction of Leptomeningeal Cells Modification Via Intracisternal Injection.

The protocol outlined here describes how to safely and manually inject solutions through the cisterna magna while eliminating the risk of damage to the underlying parenchyma. Previously published protocols recommend using straight needles that should be lowered to a maximum of 1-2 mm from the dural surface. The sudden drop in resistance once the dural membrane has been punctured makes it difficult to maintain the needle in a steady position.