A unique snake venom neuritogenesis mechanism: A cornerstone in the treatment of neurodegenerative diseases?: An Editorial Highlight for "Transcriptomic, proteomic, and biochemical analyses reveal a novel neuritogenesis mechanism of Naja naja venom α-elapitoxin post binding to TrkA receptor of rat pheochromocytoma cells" on 612

Neurodegenerative diseases are a worldwide health problem and are a major cause of death and disability. A progressive loss of defined neuronal populations is triggered by a diverse array of stimuli that converge in deficient neurotrophic signaling. Therefore, much effort has been placed in recent years in the characterization of the molecular mechanisms associated with the structure and function of neurotrophins, its receptors, signaling strategies, and their target genes. This Editorial highlights an impressive study by the group of Prof. Ashis K. Mukherjee, a renowned specialist in snake venoms, in which a component of the Indian Cobra N.naja venom with no significant similarity to nerve growth factor, is shown to induce sustained neuritogenesis. An elegant transcriptomic and functional analysis of this component, named Nn-α-elapitoxin, mapped novel domains in mammalian neurotrophic receptors that trigger both conventional and novel signal cascades that support neurite extension in the PC-12 neuronal model system. The authors discuss their findings in the context of the paradoxical neurite outgrowth properties of this toxin which originate in their unique receptor binding site. This study takes an important step towards a better understanding of the complexity of neuronal development and maintenance of the nervous system and provides a potential target to improve neurotrophic signaling, independent of endogenous growth factors, in the diseased brain.

A distinct gene expression signature characterizes human neuroblastoma cancer stem cells. Stem Cell Res. 2015;15:419-426. [PMID: 26342562 DOI: 10.1016/j.scr.2015.08.008]

Neuroblastoma, a malignancy of multipotent embryonic neural crest cells, is the most common extracranial solid cancer in childhood and most common cancer in infancy. Cellular phenotype has been shown to be an important determinant of the malignant potential in human neuroblastoma cells and tumors. Whereas neuroblastic (N-type) are moderately malignant and nonneuronal (S-type) cells are nonmalignant, I-type stem cells are highly tumorigenic, irrespective of N-myc amplification status. In the present study, we sought to determine which genes were overexpressed in the I-type cells which might characterize and maintain the stem cell state and/or malignancy of human neuroblastoma cancer stem cells. We used a microarray platform to compare the steady-state expression levels of mRNAs from 13 human neuroblastoma cell lines representing the three cellular phenotypes. Using qRT-PCR and Western blot analyses, we identified seven genes whose expression is consistently elevated exclusively in neuroblastoma cancer stem cells: CD133, KIT, NOTCH1, GPRC5C, PIGF2, TRKB, and LNGFR. Moreover, we show that the genes are phenotype specific, as differentiation of I-type BE(2)-C cells to either an N- or S-type morphology results in significantly reduced mRNA expression. Finally, we show that NOTCH1 plays an important role in maintaining the stem cell phenotype. The identification and characterization of these genes, elevated in highly malignant neuroblastoma stem cells, could provide the basis for developing novel therapies for treatment of this lethal childhood cancer.