Background: Autophagy mediates the recycling of long-lived or damaged proteins or organelles. It plays an important role in stem cell populations in particular, as these cells depend on intracellular quality control and the maintenance of cellular homeostasis. Autophagic processes have been studied in various stem cell types, including embryonic stem cells, tissue stem cells (e.g. haematopoietic or neural stem/progenitor cells (NSPCs)), cancer stem cells, and induced pluripotent stem cells (iPSCs). Previous research suggests that autophagy plays a central role in the decision between quiescence, self-renewal, and differentiation. On the one hand, cytoprotective autophagy is involved in both maintenance and neuronal differentiation of NSPCs. It has been shown that FIP200, a component of the autophagy-inducing ULK1 kinase complex, is essential for these two functions. On the other hand, it has been reported that the inhibition of autophagy reduces the radiation-induced loss of NSPCs in mice.
Aim: The influence of external stimuli on autophagic processes during neurogenesis is largely unknown. We will analyze the effects of genotoxins on autophagic processes and especially on the function of the ULK1 complex during neuronal differentiation. Furthermore, we will investigate whether the modulation of autophagic processes can influence genotoxin-mediated effects on neurogenesis.
Experimental procedure / working programme: In this project, we combine our expertise in autophagy signaling (Stork) and in the generation and differentiation of iPSCs (AG Adjaye). In the first work package, we will investigate whether treatment with genotoxins before and/or during differentiation influences the autophagic capacity of the cells using RT-qPCR, immunoblotting, and immunfluorescence. In the second work package, we will analyze whether the specific modulation of autophagy (pharmacological inhibition or activation of the ULK1 complex) influences the effects of genotoxins on cellular viability or differentiation. In the third work package, we will examine whether the applied genotoxins influence non-autophagic functions of ULK1.
- Alers, S. et al. Atg13 and FIP200 act independently of Ulk1 and Ulk2 in autophagy induction. Autophagy 7, 1423-1433, doi:10.4161/auto.7.12.18027 (2011).
- Hieke, N. et al. Expression of a ULK1/2 binding-deficient ATG13 variant can partially restore autophagic activity in ATG13-deficient cells. Autophagy 11, 1471-1483, doi:10.1080/15548627.2015.1068488 (2015).
- Löffler, A. S. et al. Ulk1-mediated phosphorylation of AMPK constitutes a negative regulatory feedback loop. Autophagy 7, 696-706, doi:10.4161/auto.7.7.15451 (2011).
- Wallot-Hieke, N. et al. Systematic analysis of ATG13 domain requirements for autophagy induction. Autophagy 14, 743-763, doi:10.1080/15548627.2017.1387342 (2018).
- Wu, W. et al. The Autophagy-Initiating Kinase ULK1 Controls RIPK1-Mediated Cell Death. Cell Rep 31, 107547, doi:10.1016/j.celrep.2020.107547 (2020).