Retromer stabilization results in neuroprotection in a model of Amyotrophic Lateral Sclerosis

Luca Muzio,Emanuele Scalone,Linda Ottoboni,Pierfausto Seneci,Luciana Marinelli,Andrea Fossaghi,Eloise Mastrangelo,Luca Sorrentino,Giancarlo Comi,Davide Gornati,Luca De Feo,Simona Eleuteri,Leonardo Manzoni,Diego Brancaccio,Nilo Riva,Mario Milani,Riccardo Sirtori,Angelo Quattrini,Gianvito Martino

doi:10.1038/s41467-020-17524-7

Abstract

Amyotrophic Lateral Sclerosis (ALS) is a fatal disease characterized by the degeneration of upper and lower motor neurons (MNs). We find a significant reduction of the retromer complex subunit VPS35 in iPSCs-derived MNs from ALS patients, in MNs from ALS post mortem explants and in MNs from SOD1G93A mice. Being the retromer involved in trafficking of hydrolases, a pathological hallmark in ALS, we design, synthesize and characterize an array of retromer stabilizers based on bis-guanylhydrazones connected by a 1,3-phenyl ring linker. We select compound 2a as a potent and bioavailable interactor of VPS35-VPS29. Indeed, while increasing retromer stability in ALS mice, compound 2a attenuates locomotion impairment and increases MNs survival. Moreover, compound 2a increases VPS35 in iPSCs-derived MNs and shows brain bioavailability. Our results clearly suggest the retromer as a valuable druggable target in ALS.

Highlights

Amyotrophic Lateral Sclerosis (ALS) is a fatal disease characterized by the degeneration of upper and lower motor neurons (MNs)
We describe a substantial reduction of cargo recognition core (CRC) proteins in MNs of G93A mice; a similar VPS35 downregulation in spinal cord (SC) from ALS patients and in inducible pluripotent stem cells-derived MNs
VPS35 immunoreactivity in cultured neurons is organized in puncta that localize throughout the cell soma, dendrites, and axons[9,22,23]

Summary

Introduction

Amyotrophic Lateral Sclerosis (ALS) is a fatal disease characterized by the degeneration of upper and lower motor neurons (MNs). While increasing retromer stability in ALS mice, compound 2a attenuates locomotion impairment and increases MNs survival. Two subcomplexes assemble in the cytoplasm to produce the retromer complex The former is a trimeric complex composed by vacuolar protein sorting (VPS) 35, 29, and 26 that assemble into the cargo recognition core (CRC) complex[9]. The retromer recycles specific cargos, such as Vps10/Sortilin protein family members[14] or the cation-independent mannose 6-phosphate receptor (CI-MPR)[15]. The latter is involved in the delivery of proteolytic enzymes to lysosomes. VPS35 deficiency alters the distribution of lysosome-associated membrane glycoprotein 2a (Lamp2a) in neurons[19]

Methods

Results

Conclusion