Radiotherapy in children causes debilitating cognitive decline, partly linked to impaired neurogenesis. Irradiation targets primarily cancer cells but also endogenous neural stem/progenitor cells (NSPCs) leading to cell death or cell cycle arrest. Here we evaluated the effects of lithium on proliferation, cell cycle and DNA damage after irradiation of young NSPCs in vitro.NSPCs were treated with 1 or 3 mM LiCl and we investigated proliferation capacity (neurosphere volume and bromodeoxyuridine (BrdU) incorporation). Using flow cytometry, we analysed apoptosis (annexin V), cell cycle (propidium iodide) and DNA damage (γH2AX) after irradiation (3.5 Gy) of lithium-treated NSPCs.Lithium increased BrdU incorporation and, dose-dependently, the number of cells in replicative phase as well as neurosphere growth. Irradiation induced cell cycle arrest in G1 and G2/M phases. Treatment with 3 mM LiCl was sufficient to increase NSPCs in S phase, boost neurosphere growth and reduce DNA damage. Lithium did not affect the levels of apoptosis, suggesting that it does not rescue NSPCs committed to apoptosis due to accumulated DNA damage.Lithium is a very promising candidate for protection of the juvenile brain from radiotherapy and for its potential to thereby improve the quality of life for those children who survive their cancer.

during cancer treatment. neural stem cells and is a selective target for neuroprotection HCN channel activity balances quiescence and proliferation in Updated version

Pluripotent stem cells are the starting cell type of choice for the development of many cell-based regenerative therapies due to their rapid and unlimited proliferation and broad differentiation potential. The unique pluripotent cell cycle underlies both these properties. Hyperpolarization-activated cyclic nucleotide-gated cation (HCN) family channels have previously been reported to modulate mouse embryonic stem cell (ESC) proliferation and here we characterize the effects of HCN inhibitor ZD7288 on ESC proliferation and stem cell identity. The doubling time of cells treated with the HCN blocker increased by ~30 % due to longer G1 and S phases, resulting in a nearly twofold reduction in ESC numbers after 4 day serum-free culture. Slower progression through S phase was not accompanied by H2AX phosphorylation or cell stalling at transition points, although EdU incorporation in treated cells was reduced. Despite the drastic cell cycle perturbations, the pluripotent status of the cells was not compromised by treatment. Cultures treated with the HCN blocker in maintenance conditions maintained pluripotency marker expression on both RNA and protein level, although we observed a reversible effect on morphology and colony formation frequency. Addition of ZD7288 in differentiating media improved FBS-driven differentiation, but not directed differentiation to neuroectoderm, further indicating that altered cell cycle structure does not necessarily compromise pluripotency and drive ESCs to differentiation. The categorically different outcomes of ZD7288 use during differentiation indicate that cell culture context can be determinative for effects of ion-modulatory molecules and underscores the need for exploring their action in serum-free conditions demanded by potential clinical use.Electronic supplementary materialThe online version of this article (doi:10.1186/s40064-016-1678-7) contains supplementary material, which is available to authorized users.