Cellular Polyamines Promote the Aggregation of α-Synuclein

Abstract

The cellular polyamines putrescine, spermidine, and spermine accelerate the aggregation and fibrillization of ␣-synuclein, the major protein component of Lewy bodies associated with Parkinson's disease. Circular dichroism and fluorometric thioflavin T kinetic studies showed a transition of ␣-synuclein from unaggregated to highly aggregated states, characterized by lag and transition phases. In the presence of polyamines, both the lag and transition times were significantly shorter. All three polyamines accelerated the aggregation and fibrillization of ␣-synuclein to a degree that increased with the total charge, length, and concentration of the polyamine. Electron and scanning force microscopy of the reaction products after the lag phase revealed the presence of aggregated particles (protofibrils) and small fibrils. At the end of the transition phase, ␣-synuclein formed long fibrils in all cases, although some morphological variations were apparent. In the presence of polyamines, fibrils formed large networks leading ultimately to condensed aggregates. In the absence of polyamines, fibrils were mostly isolated. We conclude that the polyamines at physiological concentrations can modulate the propensity of ␣-synuclein to form fibrils and may hence play a role in the formation of cytosolic ␣-synuclein aggregates.

Polyamine pathway contributes to the pathogenesis of Parkinson disease

“…A previous study showed that PD patients have elevated levels of spermidine and spermine in red blood cells (13), which do not themselves produce polyamines. Another study showed that in an in vitro system, exogenously added spermidine and spermine accelerate the aggregation of α-synuclein (12). Furthermore, previous studies have shown that SAT1 is expressed in numerous brain regions implicated in PD, including the substantia nigra pars compacta (33).…”

“…Previous in vitro studies have suggested that polyamines increase the aggregation of α-synuclein (12,15,16). To investigate the relationship between polyamines and α-synuclein in an in vivo system, we turned to an established yeast model of α-synuclein toxicity (17).…”

“…SAT1 is the rate-limiting catabolic enzyme in the polyamine metabolic pathway (11), and a decrease in SAT1 expression results in increased levels of higher-order polyamines, spermine and spermidine. Notably, previous studies have suggested that polyamines increase α-synuclein aggregation (12,13) in in vitro systems. Accordingly, we completed a wide range of additional studies using yeast models, mouse models, and human genetics to address separate but complementary questions about the pathogenicity of the polyamine pathway in PD.…”

Polyamine patterns in the cerebrospinal fluid of patients with Parkinson's disease and multiple system atrophy

“…Physiological polyamines (putrescine, cadaverine, spermidine, and spermine), the naturally occurring di, tri-, and tetra amines, are closely related to neuronal cell biochemical activity in the brain, including interaction with neurotransmitter receptors such as the Nmethyl-D-aspartate receptor, regulation of substances in degenerating cells, ion channels such as K + and protection of neuronal cells from oxidative damage [5][6][7][8][9][10]. Additionally, administration of spermine reduces infarction in cerebral ischemic rat models [11], although the systemic role of altered PAs has not been well studied.…”

Rapid Anionic Micelle-mediated α-Synuclein Fibrillization in Vitro

“…These vectors drive the expression of poly-His-tagged and non-tagged ␣-synuclein, respectively (38). His-tagged ␣-synuclein protein was expressed and purified as described previously for tau protein (38), whereas non-tagged ␣-synuclein was prepared as in Antony et al (31) except that Mono Q chromatography was used as the anion exchange resin. Because these preparations behaved similarly in all assays described below, the His-tagged form was used for experimentation for ease of preparation.…”