Neurogenesis in the postnatal cerebellum after injury

Abstract

The cerebellum plays major role in motor coordination and learning. It contains half of the neurons in the brain. Thus, deciphering the mechanisms by which cerebellar neurons are generated is essential to understand the cerebellar functions and the pathologies associated with it. In a recent study, Wojcinski et al. (2017) by using in vivo Cre/loxP technologies reveal that Nestin-expressing progenitors repopulated the external granular cell layer after injury. Depletion of postnatal external granular cell layer is not sufficient to induce motor behavior defects in adults, as the cerebellum recovers these neurons. Strikingly, Nestin-expressing progenitors differentiate into granule cell precursors and mature granule neurons after ablation of perinatal external granular layer, either by irradiation or by genetic ablation. This work identified a novel role of Nestin-expressing progenitors in the cerebellar microenvironment during development, and revealed that extracellular signals can convert specified progenitors into multipotent stem cells. Here, we discuss the findings from this study, and evaluate recent advances in our understanding of the cerebellar neurogenesis.

Keywords: Cerebellum; Nestin; Neurogenesis; Progenitors.

Figure 1. Cerebellar Nestin-expressing progenitors replenish the external granular cell layer after injury.

The neural cells that form the cerebellum originate in a sequential way during the embryonic and postnatal development. The study of Wojcinski and colleagues now reveals that cerebellar Nestin-expressing progenitors in the Purkinje cell layer, which during normal development only form interneurons and astroglia, extend their differentiation capacity, and originate mature granule neurons after injury (Wojcinski et al., 2017).