| First Author | Chen K | Year | 2022 |
| Journal | Mol Neurodegener | Volume | 17 |
| Issue | 1 | Pages | 57 |
| PubMed ID | 36056345 | Mgi Jnum | J:328336 |
| Mgi Id | MGI:7335556 | Doi | 10.1186/s13024-022-00560-w |
| Citation | Chen K, et al. (2022) LRP1 is a neuronal receptor for alpha-synuclein uptake and spread. Mol Neurodegener 17(1):57 |
| abstractText | BACKGROUND: The aggregation and spread of alpha-synuclein (alpha-Syn) protein and related neuronal toxicity are the key pathological features of Parkinson's disease (PD) and Lewy body dementia (LBD). Studies have shown that pathological species of alpha-Syn and tau can spread in a prion-like manner between neurons, although these two proteins have distinct pathological roles and contribute to different neurodegenerative diseases. It is reported that the low-density lipoprotein receptor-related protein 1 (LRP1) regulates the spread of tau proteins; however, the molecular regulatory mechanisms of alpha-Syn uptake and spread, and whether it is also regulated by LRP1, remain poorly understood. METHODS: We established LRP1 knockout (LRP1-KO) human induced pluripotent stem cells (iPSCs) isogenic lines using a CRISPR/Cas9 strategy and generated iPSC-derived neurons (iPSNs) to test the role of LRP1 in alpha-Syn uptake. We treated the iPSNs with fluorescently labeled alpha-Syn protein and measured the internalization of alpha-Syn using flow cytometry. Three forms of alpha-Syn species were tested: monomers, oligomers, and pre-formed fibrils (PFFs). To examine whether the lysine residues of alpha-Syn are involved in LRP1-mediated uptake, we capped the amines of lysines on alpha-Syn with sulfo-NHS acetate and then measured the internalization. We also tested whether the N-terminus of alpha-Syn is critical for LRP1-mediated internalization. Lastly, we investigated the role of Lrp1 in regulating alpha-Syn spread with a neuronal Lrp1 conditional knockout (Lrp1-nKO) mouse model. We generated adeno-associated viruses (AAVs) that allowed for distinguishing the alpha-Syn expression versus spread and injected them into the hippocampus of six-month-old Lrp1-nKO mice and the littermate wild type (WT) controls. The spread of alpha-Syn was evaluated three months after the injection. RESULTS: We found that the uptake of both monomeric and oligomeric alpha-Syn was significantly reduced in iPSNs with LRP1-KO compared with the WT controls. The uptake of alpha-Syn PFFs was also inhibited in LRP1-KO iPSNs, albeit to a much lesser extent compared to alpha-Syn monomers and oligomers. The blocking of lysine residues on alpha-Syn effectively decreased the uptake of alpha-Syn in iPSNs and the N-terminus of alpha-Syn was critical for LRP1-mediated alpha-Syn uptake. Finally, in the Lrp1-nKO mice, the spread of alpha-Syn was significantly reduced compared with the WT littermates. CONCLUSIONS: We identified LRP1 as a key regulator of alpha-Syn neuronal uptake, as well as an important mediator of alpha-Syn spread in the brain. This study provides new knowledge on the physiological and pathological role of LRP1 in alpha-Syn trafficking and pathology, offering insight for the treatment of synucleinopathies. |
