Neural stem cells respond to stress hormones: distinguishing beneficial from detrimental stress

Abstract

Neural stem cells (NSCs), the progenitors of the nervous system, control distinct, position-specific functions and are critically involved in the maintenance of homeostasis in the brain. The responses of these cells to various stressful stimuli are shaped by genetic, epigenetic, and environmental factors via mechanisms that are age and developmental stage-dependent and still remain, to a great extent, elusive. Increasing evidence advocates for the beneficial impact of the stress response in various settings, complementing the extensive number of studies on the detrimental effects of stress, particularly in the developing brain. In this review, we discuss suggested mechanisms mediating both the beneficial and detrimental effects of stressors on NSC activity across the lifespan. We focus on the specific effects of secreted factors and we propose NSCs as a “sensor,” capable of distinguishing among the different stressors and adapting its functions accordingly. All the above suggest the intriguing hypothesis that NSCs are an important part of the adaptive response to stressors via direct and indirect, specific mechanisms.

Environmental enrichment and physical exercise revert behavioral and electrophysiological impairments caused by reduced adult neurogenesis

“…This is reinforced by the fact that transgenics showed increased freezing already during acquisition, suggesting that this behavior is more related to exacerbated reaction to the electric shock as stressor than to emotional learning. Thus newborn neurons seem to play a decisive role when the organism must confront novelty and complex situations, for instance, stressful events (Surget et al, ; Koutmani and Karalis, ).…”

Effects of antenatal glucocorticoids on the developing brain

“…A recent study examined antenatal betamethasone administration and demonstrated that antenatal sGC therapy induces immediate hormonal alterations in the fetus 36 . Depending on the nature of the exposure, HPA function may demonstrate increased or decreased reactivity to GC 2,3,37–39 . Neural stem/progenitor cells (NSPCs) are especially sensitive to increased levels of GCs, and recent evidence suggests the extent of exposure may have life-long effects on NSPCs, which ultimately shape brain development and behavior 39–45 .…”

“…Depending on the nature of the exposure, HPA function may demonstrate increased or decreased reactivity to GC 2,3,37–39 . Neural stem/progenitor cells (NSPCs) are especially sensitive to increased levels of GCs, and recent evidence suggests the extent of exposure may have life-long effects on NSPCs, which ultimately shape brain development and behavior 39–45 . It is important to recognize that many of the effects of GCs in the developing brain are necessary for proper development and have positive effects including NSPC proliferation, differentiation and survival 2,3,39 .…”

Severity of Early Life Stress Moderates the Effect of Fine Particle Air Pollution on Adolescent Brain Development

“…Interestingly, ELS affects many of these same biological pathways implicated in apoptosis and neurogenesis, allostatic load, and inflammation (20,21,38). In the present study, the brain regions that showed greater contraction, or shrinking, related to severe ELS or increased PM2.5 may be experiencing accelerated cell death.…”