Rodent CNS neuroblasts exhibit both perpendicular and parallel contact guidance on the aligned parallel neurite bundle

Development ◽  
1991 ◽  
Vol 112 (2) ◽  
pp. 581-590
Author(s):  
I. Nagata ◽  
N. Nakatsuji

Mouse cerebellar granule cells showed two types of migration behavior in microexplant cultures. They first migrated along their neurites, showing the typical contact guidance, and then oriented themselves at right angles to the parallel neurites, thus exhibiting the ‘perpendicular contact guidance’ (Nakatsuji, N. and Nagata, I. 1989 Development, 106, 441–447). To study whether other neurons have the capacity to show similar ‘perpendicular contact guidance’, we cultured dissociated neuroblasts from various parts of CNS or PNS on parallel neurite bundles. The PNS neuroblasts always extended their processes parallel to the neurite bundle. In contrast, almost all kinds of CNS neuroblasts tested oriented their processes both perpendicular and parallel to the neurite bundles that were all free of glia. Time-lapse video recording revealed that neuroblasts migrated in both directions. Thus, CNS neuroblasts possess the capacity to migrate and extend their processes at right angles to the substratum of heterotypic neurite bundles, which may play an important role in histogenesis of the CNS during development.

Development ◽  
2002 ◽  
Vol 129 (6) ◽  
pp. 1435-1442 ◽  
Author(s):  
Paul R. Borghesani ◽  
Jean Michel Peyrin ◽  
Robyn Klein ◽  
Joshua Rubin ◽  
Alexandre R. Carter ◽  
...  

During development of the nervous system, neural progenitors arise in proliferative zones, then exit the cell cycle and migrate away from these zones. Here we show that migration of cerebellar granule cells out of their proliferative zone, the external granule cell layer (EGL), is impaired in Bdnf–/– mice. The reason for impaired migration is that BDNF directly and acutely stimulates granule cell migration. Purified Bdnf–/– granule cells show defects in initiation of migration along glial fibers and in Boyden chamber assays. This phenotype can be rescued by exogenous BDNF. Using time-lapse video microscopy we find that BDNF is acutely motogenic as it stimulates migration of individual granule cells immediately after addition. The stimulation of migration reflects both a chemokinetic and chemotactic effect of BDNF. Collectively, these data demonstrate that BDNF is directly motogenic for granule cells and provides a directional cue promoting migration from the EGL to the internal granule cell layer (IGL). Movies available on-line


BMC Biology ◽  
2021 ◽  
Vol 19 (1) ◽  
Author(s):  
Wenqin Luo ◽  
Guan Ning Lin ◽  
Weichen Song ◽  
Yu Zhang ◽  
Huadong Lai ◽  
...  

Abstract Background Cerebellar neurogenesis involves the generation of large numbers of cerebellar granule neurons (GNs) throughout development of the cerebellum, a process that involves tight regulation of proliferation and differentiation of granule neuron progenitors (GNPs). A number of transcriptional regulators, including Math1, and the signaling molecules Wnt and Shh have been shown to have important roles in GNP proliferation and differentiation, and deregulation of granule cell development has been reported to be associated with the pathogenesis of medulloblastoma. While the progenitor/differentiation states of cerebellar granule cells have been broadly investigated, a more detailed association between developmental differentiation programs and spatial gene expression patterns, and how these lead to differential generation of distinct types of medulloblastoma remains poorly understood. Here, we provide a comparative single-cell spatial transcriptomics analysis to better understand the similarities and differences between developing granule and medulloblastoma cells. Results To acquire an enhanced understanding of the precise cellular states of developing cerebellar granule cells, we performed single-cell RNA sequencing of 24,919 murine cerebellar cells from granule neuron-specific reporter mice (Math1-GFP; Dcx-DsRed mice). Our single-cell analysis revealed that there are four major states of developing cerebellar granule cells, including two subsets of granule progenitors and two subsets of differentiating/differentiated granule neurons. Further spatial transcriptomics technology enabled visualization of their spatial locations in cerebellum. In addition, we performed single-cell RNA sequencing of 18,372 cells from Patched+/− mutant mice and found that the transformed granule cells in medulloblastoma closely resembled developing granule neurons of varying differentiation states. However, transformed granule neuron progenitors in medulloblastoma exhibit noticeably less tendency to differentiate compared with cells in normal development. Conclusion In sum, our study revealed the cellular and spatial organization of the detailed states of cerebellar granule cells and provided direct evidence for the similarities and discrepancies between normal cerebellar development and tumorigenesis.


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