Discovery of a Necroptosis Inhibitor Improving Dopaminergic Neuronal Loss after MPTP Exposure in Mice.

Sara R Oliveira,Mónica S Estevão,Maria J Perry,Cecília M P Rodrigues,Rui Moreira,Catarina A B Rodrigues,Carlos A M Afonso,Joana D Amaral,Rita G Pereira,Maria B T Ferreira,Pedro A Dionísio,Maria M Gaspar

doi:10.3390/ijms22105289

Sara R Oliveira, Mónica S Estevão + Show 10 more

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https://doi.org/10.3390/ijms22105289

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Abstract

Parkinson’s disease (PD) is the second most common neurodegenerative disorder, mainly characterized by motor deficits correlated with progressive dopaminergic neuronal loss in the substantia nigra pars compacta (SN). Necroptosis is a caspase-independent form of regulated cell death mediated by the concerted action of receptor-interacting protein 3 (RIP3) and the pseudokinase mixed lineage domain-like protein (MLKL). It is also usually dependent on RIP1 kinase activity, influenced by further cellular clues. Importantly, necroptosis appears to be strongly linked to several neurodegenerative diseases, including PD. Here, we aimed at identifying novel chemical inhibitors of necroptosis in a PD-mimicking model, by conducting a two-step screening. Firstly, we phenotypically screened a library of 31 small molecules using a cellular model of necroptosis and, thereafter, the hit compound effect was validated in vivo in a sub-acute 1-methyl-1-4-phenyl-1,2,3,6-tetrahydropyridine hydrochloride (MPTP) PD-related mouse model. From the initial compounds, we identified one hit—Oxa12—that strongly inhibited necroptosis induced by the pan-caspase inhibitor zVAD-fmk in the BV2 murine microglia cell line. More importantly, mice exposed to MPTP and further treated with Oxa12 showed protection against MPTP-induced dopaminergic neuronal loss in the SN and striatum. In conclusion, we identified Oxa12 as a hit compound that represents a new chemotype to tackle necroptosis. Oxa12 displays in vivo effects, making this compound a drug candidate for further optimization to attenuate PD pathogenesis.

Highlights

Parkinson’s disease (PD) is the second most common neurodegenerative disorder worldwide
The pathological mechanisms causing PD are thought to stimulate a cascade of events that activate regulated cell death (RCD) pathways, which are responsible for neuronal death [3,4]
Previous studies have demonstrated that the pan-caspase inhibitor zVAD-fmk induces necroptosis in different cellular models, including in the L929 fibrosarcoma and in the BV2 murine microglial cell lines, by a mechanism that most likely depends on tumor necrosis factor (TNF) autocrine secretion [12,21,22]

Summary

Introduction

Parkinson’s disease (PD) is the second most common neurodegenerative disorder worldwide. The pathological mechanisms causing PD are thought to stimulate a cascade of events that activate regulated cell death (RCD) pathways, which are responsible for neuronal death [3,4]. Recent evidence has shown that necroptosis, a type of regulated necrosis, plays crucial pathogenic roles in several human diseases, including neurodegenerative diseases, such as PD, while holding high potential for clinical targeting [5]. Necroptosis is a caspase-independent type of RCD commonly executed after RIP1 and RIP3 kinase activation. This type of cell death is initiated following cell death transmembrane receptor stimulation, with tumor necrosis factor (TNF) receptor 1 (TNFR1) being the most well-studied example [6,7]. Necroptosis has already been associated with neuronal death induced by the neurotoxin

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