Figure 2. Lfng-eGFP-expressing cells are functional NSCs.

(A) Most Lfng-eGFP⁺ NSCs are quiescent. Bar graphs represent the total number of GFP⁺ cells (left panel), GFP⁺ NSCs (middle panel) and GFP⁺ ANPs (right panel) in 3 month-old Nestin-GFP and Lfng-eGFP mice (N = 4 per genotype) treated with temozolomide (TMZ). The difference between the two mouse models is most notable with respect to ANPs: while Nestin-GFP labels a large number of ANPs, Lfng-eGFP does not - it labels primarily quiescent cells. (B) Electroconvulsive shock (ECS) and physical exercise (PE) both activate Lfng-eGFP⁺ NSCs (N = 4 per group in ECS and N = 6 per group in PE). (C) Lfng-eGFP NSCs produce neuronal progeny. The relative number of newborn, BrdU⁺ progeny was quantified over a 30 day period (NSCs: Nestin-GFP⁺ or Lfng-eGFP⁺ cells with GFAP⁺ radial processes; ANPs: GFAP^- Dcx^- NeuN^-; NBs: Dcx⁺ neuroblasts and immature neurons; GCs: NeuN⁺; Other: BrdU⁺ Dcx^- NeuN^- cells outside the SGZ; N = 4 per genotype per timepoint). Cumulative BrdU paradigm (four 150 mg/kg injections given 2 hr apart) was used to increase the yield of labeled newborn cells. N=Nestin-GFP mice, L=Lfng-eGFP mice. (D) The number of Lfng-eGFP⁺ NSCs declines over an 18 month period comparably to the number of Nestin-GFP⁺ NSCs (left panel; N = 4 per timepoint per genotype). However, the contribution of GFP⁺ cell types in the Nestin-GFP and Lfng-eGFP mice differs at different age (right panel). While Lfng-eGFP remains selective for NSCs during aging (p>0.15 for all timepoints, Tukey post-hoc test), Nestin-GFP labels significantly more non-neuroprogenitors in older mice (p<0.002; Tukey post-hoc test). Bars represent mean±SEM. NS=non-significant, *p<0.05, **p<0.001. See Figure 2—figure supplement 1 for further details.

DOI: http://dx.doi.org/10.7554/eLife.24660.004

Figure 2—figure supplement 1. The specificity of Lfng-eGFP expression for NSCs does not change over time.

(A) The total number of BrdU⁺ cells (NSCs and their progeny) in Nestin-GFP and Lfng- eGFP mice over a 30 day period indicates that cell survival is similar in both mouse models. (B) Neither the total number BrdU⁺ cells (left panel) nor the relative number of BrdU⁺ NSCs (right panel) in Nestin-GFP and Lfng-eGFP mice significantly differs over the 18 month period investigated (N = 4 per genotype per timepoint), indicating that the proliferative capacity of NSCs in the two mouse models is similar. (C) Confocal photomicrographs are representative examples of the dentate gyri of Nestin-GFP and Lfng-eGFP mice at a given age. Note a decline in the number of GFP⁺ NSCs in both models. However, while the GFP⁺ non-progenitors (‘other cells’) prevail as the Nestin-GFP mice age, in the Lfng-eGFP mice eGFP remains expressed in NSCs and the contribution of the GFP⁺‘other cells’ is minimal. See Figure 2D for quantification. Bars represent mean ± SEM. Scale bar = 20 µm.

DOI: http://dx.doi.org/10.7554/eLife.24660.005