# Lab life, seasons and chromosome fusions affect non-cell-autonomously proliferation and neurogenesis, but not oligodendrogenesis, in mice and voles

## TL;DR

Lab conditions, seasons, and chromosome changes affect brain cell growth in mice and voles, but not all cell types are impacted.

## Contribution

The study reveals non-cell-autonomous effects of environmental and chromosomal factors on neurogenesis in wild and lab animals.

## Key findings

- Lab mice and wild voles show lower NSPC and neuroblast density in the Subependymal Zone compared to wild mice.
- Neurogenesis decreases with fewer chromosomes due to Robertsonian fusions, but oligodendrogenesis remains unaffected.
- Environmental and genetic effects are mediated non-cell-autonomously, as cultured NSPCs showed no differences.

## Abstract

Environmental and behavioral factors have been shown, in experimental settings, to affect neurogenesis in the mouse brain. We found that the density of proliferating neural stem/progenitor cells (NSPCs) and of neuroblasts was significantly lower in the Subependymal Zone stem cell niche of lab mice when compared with mice and pine voles captured in the wild, with seasonal variation observed only in voles. Moreover, levels of proliferation and neurogenesis were found to decrease in proportion to the decrease in the numbers of chromosomes (from the typical 2n = 40 down to 2n = 26) caused by Robertsonian fusions. In contrast, oligodendroglial progenitors and microglial cells were unaffected by wildlife, seasons and chromosomal fusions. When NSPCs were grown in cultures no differences were detected, suggesting that environmental and genetic effects are mediated by non-cell-autonomous mechanisms. These “real-world” data provide a platform for the identification of systemic factors and genetic loci that control postnatal brain neurogenesis.