Discovery of a ULK1 activator that induces autophagy in vitro and in vivo Parkinson＇ s disease models

Aim It has been widely accepted that autophagy plays a key role in some human diseases such as Par- kinson＇ s disease （PD）. UNC-51-1ike kinasesl （ ULK1 ） has been widely reported to initiate autophagy via its com- plex ULKl-mAtg13-FIP200 at the first stage; however, targeting ULK1 as a therapeutic strategy in PD still remains in its infancy. This study aimed at developing a novel ULK1 activator as candidate drugs for PD therapy and valida- ting the possible mechanism and efficacy in vitro and in vivo. Methods Sequence alignment, phylogenetic analy- sis, homology modeling, molecular dockingand structure modificationwere applied forscreening of candidate com- pounds. Surface plasmon resonance （SPR） analysis and molecular dynamics （MD） simulations were carried outto prove the binding betweenULKland BL-UA07. Observations of cell morphology were executed through several methods including MDC staining and GFP-LC3 transfection. Flow cytometric analysis of MDC was used for quantifi- cation of autophagy ratio. Western blot and RNAi transfection were used to explore the detailed mechanisms of BL- UA07-induced autophagy. Furthermore, an in vivo PD mouse model was established for validating the PD treatment efficacy of BL-UA07. Results After a series of screening and structure modification, a novel compound BL-UA07 targeting ULK1 was obtained, which couldeffectivelybind with its target. Then, our results showed that BL-UA07 could induce autophagy via ULK1 complex and decrease damage induced by MPP ~ in SH-SY5Y cells. In addition, in vivomouse model was established to evaluate the protective effect of BL-UA07. The results demonstrated that BL- UA07 has a therapeutic effect on the in vivomouse model without apparent toxicity, which is dependent on the cyto- protective autophagy mediated by ULK1. Conclusion In this study, a novel specific ULK1 activator （BL-UA07） was computationally designed, chemically synthesized and biologically validatedthat could induce cytoprotective au- tophagy in neuroblastoma SH-SYSY cells and in vivo mouse models. Together, these results may uncover this small-molecule compound BL-UA07 as a novel ULK1 activator in autophagy and thus would provide a new clue for exploring more candidate drug targeting ULK1 for future PD therapy.