TY - JOUR
T1 - T-type ca2+ enhancer sak3 activates camkii and proteasome activities in lewy body dementia mice model
AU - Xu, Jing
AU - Kawahata, Ichiro
AU - Izumi, Hisanao
AU - Fukunaga, Koji
N1 - Funding Information:
Acknowledgments: Jing Xu gratefully appreciates the LOTTE Foundation for its financial support.
Funding Information:
Funding: This work was supported in part by the Strategic Research Program for Brain Sciences from the Japan Agency for Medical Research and Development (JP17dm0107071, JP18dm0107071, JP19dm0107071, and JP20dm0107071 [to K.F.]), and the Smoking Research Foundation (to I.K.).
Publisher Copyright:
© 2021 by the authors. Licensee MDPI, Basel, Switzerland.
PY - 2021/6/2
Y1 - 2021/6/2
N2 - Lewy bodies are pathological characteristics of Lewy body dementia (LBD) and are composed of α-synuclein (α-Syn), which is mostly degraded via the ubiquitin–proteasome system. More importantly, 26S proteasomal activity decreases in the brain of LBD patients. We recently introduced a T-type calcium channel enhancer SAK3 (ethyl-8-methyl-2,4-dioxo-2-(piperidin-1-yl)2H-spiro[cyclopentane-1,3-imidazo [1,2-a]pyridin]-2-ene-3-carboxylate) for Alzheimer’s disease therapeutics. SAK3 enhanced the proteasome activity via CaMKII activation in amyloid precursor protein knock-in mice, promoting the degradation of amyloid-β plaques to improve cognition. At this point, we addressed whether SAK3 promotes the degradation of misfolded α-Syn and the aggregates in α-Syn preformed fibril (PFF)-injected mice. The mice were injected with α-Syn PFF in the dorsal striatum, and SAK3 (0.5 or 1.0 mg/kg) was administered orally for three months, either immediately or during the last month after injection. SAK3 significantly inhibited the accumulation of fibrilized phosphorylated-α-Syn in the substantia nigra. Accordingly, SAK3 significantly recovered mesencephalic dopamine neurons from cell death. Decreased α-Syn accumulation was closely associated with increased proteasome activity. Elevated CaMKII/Rpt-6 signaling possibly mediates the enhanced proteasome activity after SAK3 administration in the cortex and hippocampus. CaMKII/Rpt-6 activation also accounted for improved memory and cognition in α-Syn PFF-injected mice. These findings indicate that CaMKII/Rpt-6-dependent proteasomal activation by SAK3 recovers from α-Syn pathology in LBD.
AB - Lewy bodies are pathological characteristics of Lewy body dementia (LBD) and are composed of α-synuclein (α-Syn), which is mostly degraded via the ubiquitin–proteasome system. More importantly, 26S proteasomal activity decreases in the brain of LBD patients. We recently introduced a T-type calcium channel enhancer SAK3 (ethyl-8-methyl-2,4-dioxo-2-(piperidin-1-yl)2H-spiro[cyclopentane-1,3-imidazo [1,2-a]pyridin]-2-ene-3-carboxylate) for Alzheimer’s disease therapeutics. SAK3 enhanced the proteasome activity via CaMKII activation in amyloid precursor protein knock-in mice, promoting the degradation of amyloid-β plaques to improve cognition. At this point, we addressed whether SAK3 promotes the degradation of misfolded α-Syn and the aggregates in α-Syn preformed fibril (PFF)-injected mice. The mice were injected with α-Syn PFF in the dorsal striatum, and SAK3 (0.5 or 1.0 mg/kg) was administered orally for three months, either immediately or during the last month after injection. SAK3 significantly inhibited the accumulation of fibrilized phosphorylated-α-Syn in the substantia nigra. Accordingly, SAK3 significantly recovered mesencephalic dopamine neurons from cell death. Decreased α-Syn accumulation was closely associated with increased proteasome activity. Elevated CaMKII/Rpt-6 signaling possibly mediates the enhanced proteasome activity after SAK3 administration in the cortex and hippocampus. CaMKII/Rpt-6 activation also accounted for improved memory and cognition in α-Syn PFF-injected mice. These findings indicate that CaMKII/Rpt-6-dependent proteasomal activation by SAK3 recovers from α-Syn pathology in LBD.
KW - Alpha-synuclein
KW - Alzheimer’s disease
KW - Amyloid β plaque
KW - Lewy body dementia
KW - Proteasome activity
KW - SAK3
KW - T-type Ca channel enhancer
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UR - http://www.scopus.com/inward/citedby.url?scp=85107378053&partnerID=8YFLogxK
U2 - 10.3390/ijms22126185
DO - 10.3390/ijms22126185
M3 - Article
C2 - 34201181
AN - SCOPUS:85107378053
VL - 22
JO - International Journal of Molecular Sciences
JF - International Journal of Molecular Sciences
SN - 1422-0067
IS - 12
M1 - 6185
ER -