Naringenin and SMER28 target lysosomal reformation and rescue SPG11 and SPG15 hereditary spastic paraplegia phenotypes

: SPG11 and SPG15 are two Hereditary Spastic Paraplegia forms characterized by autophagosome accumulation, reduced free lysosomes and defects in autophagic lysosomal reformation (ALR). We demonstrated that attempts to rescue ALR and/or lysosome biogenesis are critical strategies for SPG15 phenotype and that SMER28 improved lysosomal reformation rescuing locomotor deficit in a SPG15 Drosophila model. Here we assessed the therapeutic potential of two FDA-approved compounds, tideglusib and naringenin, that target lysosomal function and regeneration, both registered for clinical use. Their effects were compared with those of SMER28 and of miglustat, the latter tested in a phase II clinical trial in SPG11 patients, in both SPG15 and SPG11 patient's derived cells and in the corresponding Drosophila models. We demonstrated that naringenin and SMER28 restored lysosomal and autophagic parameters in SPG15 and SPG11 cells and fly models, rescued ALR and improved locomotor deficit in vivo. Both compounds induced lysosomal tubulation, downstream of mTOR, promoting lysosomal reformation. Our work indicates that lysosomal reformation is a good strategy for HSPs with impaired lysosomal function and identifies naringenin as new modulator of this process, offering further hand to planning phase II clinical trials in SPG11-SPG15 patients.