TY - JOUR
T1 - Protopine promotes the proteasomal degradation of pathological tau in Alzheimer's disease models via HDAC6 inhibition
AU - Sreenivasmurthy, Sravan Gopalkrishnashetty
AU - Iyaswamy, Ashok
AU - Krishnamoorthi, Senthilkumar
AU - Senapati, Sanjib
AU - Malampati, Sandeep
AU - Zhu, Zhou
AU - Su, Cheng Fu
AU - Liu, Jia
AU - Guan, Xin Jie
AU - Tong, Benjamin Chun Kit
AU - Cheung, King Ho
AU - Tan, Jie Qiong
AU - Lu, Jia Hong
AU - Durairajan, Siva Sundara Kumar
AU - Song, Ju Xian
AU - Li, Min
N1 - Funding Information:
This study was supported by the Innovation Technology Fund (ITS/187/13), Hong Kong Health and Medical Research Fund (HMRF/15163481, HMRF/17182541) and the Hong Kong General Research Fund (HKBU 12100618, HKBU 12101417) from Hong Kong Government. The study was partly supported by the Research Fund from Hong Kong Baptist University (HKBU/RC-IRCs/17-18/03, FRGII/17-18/021), and supported by National Natural Science Foundation of China (NSFC 81773926, NSFC 81703487) and Basic Research Fund from Shenzhen Science and Technology Program (JCYJ20180507184656626, JCYJ20180302174028790).
Publisher Copyright:
© 2021 Elsevier GmbH.
PY - 2022/2
Y1 - 2022/2
N2 - Background: Collective evidences have indicated that intracellular accumulation of hyperphosphorylated tau forms neurofibrillary tangles in the brain, which impairs memory, cognition and affects social activities in Alzheimer's disease (AD). Purpose: To investigate the tau-reducing, and memory-enhancing properties of protopine (PRO), a natural alkaloid isolated from Chinese herbal medicine Corydalis yanhusuo (Yanhusuo in Chinese). Study design: By using Histone deacetylase 6 (HDAC6) profiling and immunoprecipitation assays, we assessed that PRO mediated the heat shock protein 90 (HSP90) chaperonic activities for the degradation of pathological tau in AD cell culture models. To study the efficacy of PRO in vivo, we employed 3xTg-AD and P301S tau mice models. Methods: Liquid chromatography/quadrupole time-of-flight mass spectrometry was used to analyze the pharmacokinetic profile of PRO. Seven-month-old 3xTg-AD mice and 1.5-month-old P301S mice were administered PRO (1 and 2.5 mg/kg) orally every day. Morris water maze, contextual fear conditioning and rotarod assays were applied for studying memory functions. Sarkosyl differential centrifugation was used to analyze soluble and insoluble tau. Immunohistochemical analysis were performed to determine tau deposits in AD mice's brain sections. Molecular docking, binding affinity studies and primary cell culture studies were performed to demonstrate the mechanism of action of PRO in silico and in vitro. Results: Our pharmacokinetic profiling demonstrated that PRO significantly entered the brain at a concentration of 289.47 ng/g, and specifically attenuated tau pathology, improved learning and memory functions in both 3xTg-AD and P301S mice. Docking, binding affinity studies, and fluorometric assays demonstrated that PRO directly bound to the catalytic domain 1 (CD1) of HDAC6 and down-regulated its activity. In primary cortical neurons, PRO enhanced acetylation of α-tubulin, indicating HDAC6 inhibition. Meanwhile, PRO promoted the ubiquitination of tau and recruited heat shock protein 70 (HSP70) and heat shock cognate complex 71 (HSC70) for the degradation of pathological tau via the ubiquitin-proteasomal system (UPS). Conclusion: We identified PRO as a natural HDAC6 inhibitor that attenuated tau pathology and improved memory dysfunctions in AD mice. The findings from this study provides a strong justification for future clinical development of plant-derived protopine as a novel agent for the treatment of tau-related neurodegenerative diseases.
AB - Background: Collective evidences have indicated that intracellular accumulation of hyperphosphorylated tau forms neurofibrillary tangles in the brain, which impairs memory, cognition and affects social activities in Alzheimer's disease (AD). Purpose: To investigate the tau-reducing, and memory-enhancing properties of protopine (PRO), a natural alkaloid isolated from Chinese herbal medicine Corydalis yanhusuo (Yanhusuo in Chinese). Study design: By using Histone deacetylase 6 (HDAC6) profiling and immunoprecipitation assays, we assessed that PRO mediated the heat shock protein 90 (HSP90) chaperonic activities for the degradation of pathological tau in AD cell culture models. To study the efficacy of PRO in vivo, we employed 3xTg-AD and P301S tau mice models. Methods: Liquid chromatography/quadrupole time-of-flight mass spectrometry was used to analyze the pharmacokinetic profile of PRO. Seven-month-old 3xTg-AD mice and 1.5-month-old P301S mice were administered PRO (1 and 2.5 mg/kg) orally every day. Morris water maze, contextual fear conditioning and rotarod assays were applied for studying memory functions. Sarkosyl differential centrifugation was used to analyze soluble and insoluble tau. Immunohistochemical analysis were performed to determine tau deposits in AD mice's brain sections. Molecular docking, binding affinity studies and primary cell culture studies were performed to demonstrate the mechanism of action of PRO in silico and in vitro. Results: Our pharmacokinetic profiling demonstrated that PRO significantly entered the brain at a concentration of 289.47 ng/g, and specifically attenuated tau pathology, improved learning and memory functions in both 3xTg-AD and P301S mice. Docking, binding affinity studies, and fluorometric assays demonstrated that PRO directly bound to the catalytic domain 1 (CD1) of HDAC6 and down-regulated its activity. In primary cortical neurons, PRO enhanced acetylation of α-tubulin, indicating HDAC6 inhibition. Meanwhile, PRO promoted the ubiquitination of tau and recruited heat shock protein 70 (HSP70) and heat shock cognate complex 71 (HSC70) for the degradation of pathological tau via the ubiquitin-proteasomal system (UPS). Conclusion: We identified PRO as a natural HDAC6 inhibitor that attenuated tau pathology and improved memory dysfunctions in AD mice. The findings from this study provides a strong justification for future clinical development of plant-derived protopine as a novel agent for the treatment of tau-related neurodegenerative diseases.
KW - 3xTg-AD mice
KW - Alzheimer's disease
KW - HDAC6
KW - P301S-tau mice
KW - Phospho-tau
KW - Protopine
UR - http://www.scopus.com/inward/record.url?scp=85121419828&partnerID=8YFLogxK
U2 - 10.1016/j.phymed.2021.153887
DO - 10.1016/j.phymed.2021.153887
M3 - Journal article
C2 - 34936968
AN - SCOPUS:85121419828
SN - 0944-7113
VL - 96
JO - Phytomedicine
JF - Phytomedicine
M1 - 153887
ER -
