Size-Selective Phagocytic Clearance of Fibrillar α-Synuclein through Conformational Activation of Complement Receptor 4

作者：Kristian Juul-Madsen, P. Qvist, K. L. Bendtsen, A. Langkilde, B. Vestergaard, K. Howard, M. Dehesa-Etxebeste, S. Paludan, G. Andersen, P. Jensen, D. Otzen, M. Romero-Ramos, T. Vorup-Jensen · 发表于：Journal of Immunology · 年份：2020 · DOI：10.4049/jimmunol.1900494 · 被引用次数：36 · 研究领域：Medicine、Chemistry

Key Points CR4 binds fibrillar αSN but not monomeric species. Clearance of fibrillar αSN is strongly dependent on receptor conformation. In fibrillar αSN, anionic side chain ladders may be critical for clearance. Visual Abstract Aggregation of α-synuclein (αSN) is an important histological feature of Parkinson disease. Recent studies showed that the release of misfolded αSN from human and rodent neurons is relevant to the progression and spread of αSN pathology. Little is known, however, about the mechanisms responsible for clearance of extracellular αSN. This study found that human complement receptor (CR) 4 selectively bound fibrillar αSN, but not monomeric species. αSN is an abundant protein in the CNS, which potentially could overwhelm clearance of cytotoxic αSN species. The selectivity of CR4 toward binding fibrillar αSN consequently adds an important αSN receptor function for maintenance of brain homeostasis. Based on the recently solved structures of αSN fibrils and the known ligand preference of CR4, we hypothesize that the parallel monomer stacking in fibrillar αSN creates a known danger-associated molecular pattern of stretches of anionic side chains strongly bound by CR4. Conformational change in the receptor regulated tightly clearance of fibrillar αSN by human monocytes. The induced change coupled concomitantly with phagolysosome formation. Data mining of the brain transcriptome in Parkinson disease patients supported CR4 as an active αSN clearance mechanism in t...