Mechanism underlying the effects of doxepin on β-amyloid -induced memory impairment in rats

Document Type : Original Article

Authors

Department of Neurology, Jinshan Hospital, Fudan University, JinShan District 201508, Shanghai, China

Abstract

Objective(s): In previous studies, researchers observed that doxepin could improve cognitive processes and has protective effectson the central nervous system. Thus, this study was designed to analyze the effects of doxepin on β-amyloid (Aβ)-induced memory impairment and neuronal toxicity in ratand to explore the underlying mechanism.
Materials and Methods: Rats were treated with Aβ1-42 and doxepin was injected to validate its effects on cognitive function. The Morris water maze test was performed to detect memory function.  Aβ1-42-treated SH-SY5Y human neuroblastoma cell line was also used to detect the effects of doxepin and to explore the underlying mechanism. Western blotting analysis was used to detect the protein expression levels of PSD-95, synapsin 1, p-AKT and p-mTOR in rats.
Results: After treated with 1 mg/kg of doxepin, Aβ1-42-treated rats showed markedly lower escape latency and higher platform-finding strategy score. Low doses of doxepin significantly reversed the effects of Aβ1-42 on the protein expression levels of PSD-95, synapsin 1, p-AKT and p-mTOR in rats.   In vitro experiment showed the consistent results. Besides, PI3K inhibitor (LY294002) treatment could markedly reversed the effects of doxepin on Aβ1-42-treated SH-SY5Y cells.
Conclusion: Our results demonstrated that doxepin could protect against the Aβ1-42-induced memory impairment in rats. The protective effect of doxepin was associated with the enhancement of PSD-95 and synapsin 1 expression via PI3K/AKT/mTOR signaling pathway.

Keywords


1. Tan L, Yu JT, Zhang W, Wu ZC, Zhang Q, Liu QY, et al. Association of GWAS-linked loci with late-onset Alzheimer's disease in a northern Han Chinese population. Alzheimers  Dement 2012; 9:546-553.
2. Tan MS, Yu JT, Jiang T, Zhu XC, Wang HF, Zhang W, et al. NLRP3 polymorphisms are associated with late-onset Alzheimer's disease in Han Chinese. J Neuroimmunol 2013; 265:91-95.
3. Weintraub D, Rosenberg PB, Drye LT, Martin BK, Frangakis C, Mintzer JE, et al. Sertraline for the treatment of depression in Alzheimer disease: week-24 outcomes. J Geriatr Psychiatry Neurol 2011; 24:222-228.
4. Lyketsos CG, Lopez O, Jones B, Fitzpatrick AL, Breitner J, Dekosky S. Prevalence of neuropsychiatric symptoms in dementia and mild cognitive impairment: results from the cardiovascular health study. Jama  J Am Med Assoc 2002; 288:1475-1483.
5. Nyth AL, Gottfries CG, Lyby K, Smedegaardandersen L, Gyldingsabroe J, Kristensen M, et al. A controlled multicenter clinical study of citalopram and placebo in elderly depressed patients with and without concomitant dementia. Acta Psychiatr Scand 1992; 86:138-145.
6. Mossello E, Boncinelli M, Caleri V, Cavallini MC, Palermo E, Di BM, et al. Is antidepressant treatment associated with reduced cognitive decline in Alzheimer's disease? Dement Geriatr Cogn Dis 2008; 25:372-379.
7. Vermeeren A, Coenen AM. Effects of the use of hypnotics on cognition. Prog Brain Res 2011; 190:189.
8. Drake LA, Fallon JD, Sober A. Relief of pruritus in patients with atopic dermatitis after treatment with topical doxepin cream. The Doxepin Study Group. J Am Acad Dermatol 1994; 31:613-616.
9. Hajak G, Rodenbeck A, Voderholzer U, Riemann D, Cohrs S, Hohagen F, et al. Doxepin in the treatment of primary insomnia: a placebo-controlled, double-blind, polysomnogra-phic study. J Clin Psychiatr 2001; 62:453-463.
10. Ray SK, Fidan M, Nowak MW, Wilford GG, Hogan EL, Banik NL. Oxidative stress and Ca2+ influx upregulate calpain and induce apoptosis in PC12 cells. Brain Res 2000; 852:326-334.
11. Bian-shengJI, HeJI, Guo-qingLIU. Doxepin protects cultured neurons against oxidative stress-induced injury. Acta Pharm Sin 2004; 25:297-300.
12. Gharzi M, Dolatabadi HR, Reisi P, Javanmard SH. Effects of different doses of doxepin on passive avoidance learning in rats.Adv Biomed Res  2013; 2:66.
13. Azadbakht AA, Radahmadi M, Sh HJ, Reisi P. The effects of doxepin on stress-induced learning, memory impairments, and TNF-α level in the rat hippocampus. Res Pharm Sci 2015; 10:460-465.
14.O' NC. PI3-kinase/Akt/mTOR signaling: impaired on/off switches in aging, cognitive decline and Alzheimer's disease. Exp Gerontol 2013; 48:647-653.
15. Mairetcoello G, Courchet J, Pieraut S, Courchet V, Maximov A, Polleux F. The CAMKK2-AMPK kinase pathway mediates the synaptotoxic effects of Aβ oligomers through Tau phosphorylation. Neuron 2013; 78:94.
16. Stein SC, Woods A, Jones NA, Davison MD, Carling D. The regulation of AMP-activated protein kinase by phosphorylation. Biochem J 2000; 345 Pt 3:437-443.
17. Carling D, Thornton C, Woods A, Sanders MJ. AMP-activated protein kinase: new regulation, new roles? Biochem J 2012; 445:11-27.
18. CM T, SA R, Z X, AC M, TJ C, ML S, et al. beta-Amyloid-induced neuronal apoptosis requires c-Jun N-terminal kinase activation. J Neurochem 2001; 77:157-164.
19. Lin J, Li W, Zhang XL. Effects of Gingko biloba leaf extract on the learning and memory and expression of glial fibrillary acidic protein in hippocampal astrocytes of type 2 diabetic rats. Chinese J Clin Rehabil 2006; 10:176-179.
20. Jämsä A, Hasslund K, Cowburn RF, Bäckström A, Vasänge M. The retinoic acid and brain-derived neurotrophic factor differentiated SH-SY5Y cell line as a model for Alzheimer’s disease-like tau phosphorylation. Biochem Biophys Res Commun 2004; 319:993-1000.
21. Leblanc AC, Kovacs DM, Chen HY, Villaré F, Tykocinski M, Autilio-Gambetti L, et al. Role of amyloid precursor protein (APP): study with antisense transfection of human neuroblastoma cells. J Neurosci Res 1992; 31:635-645.
22. Schonrock N, Matamales M, Ittner LM, Götz J. MicroRNA networks surrounding APP and amyloid-β metabolism--implications for Alzheimer's disease. Exp Neurol 2012; 235:447.
23. Li S, Yan Y, Jiao Y, Gao Z, Xia Y, Kong L, et al. Neuroprotective effect of osthole on neuron synapses in an alzheimer’s disease cell model via upregulation of microRNA-9. J Mol Neurosci 2016; 1-11.
24. Krystal AD, Durrence HH, Scharf M, Jochelson P, Rogowski R, Ludington E, et al. Efficacy and safety of doxepin 1 mg and 3 mg in a 12-week sleep laboratory and outpatient trial of elderly subjects with chronic primary lnsomnia. Sleep 2010; 33:1553-1561.
25. Weber J, Siddiqui MA, Wagstaff AJ, Mccormack PL. Low-dose doxepin: in the treatment of insomnia. CNS Drugs 2010; 24:713-720.
26. Chong ZZ, Shang YC, Wang S, Maiese K. A Critical kinase cascade in neurological disorders: PI 3-K, Akt, and mTOR. Future Neurol 2012; 7:733.
27. Griffin RJ, Moloney A, Kelliher M, Johnston JA, Ravid R, Dockery P, et al. Activation of Akt/PKB, increased phosphorylation of Akt substrates and loss and altered distribution of Akt and PTEN are features of Alzheimer's disease pathology. J Neurochem 2005; 93:105-117.
28.Xian YF, Lin ZX, Mao QQ, Chen JN, Su ZR, Lai XP, et al. Isorhynchophylline Protects PC12 Cells Against Beta-Amyloid-Induced Apoptosis via PI3K/Akt Signaling Pathway. Evid Based Complementary Altern Med 2013; 2013:163057.