title: Induction of autophagy by spermidine is neuroprotective via inhibition of caspase 3-mediated Beclin 1 cleavage.
abstract: Spermidine, a natural polyamine presented widely in mammalian cells, has been implicated to extend the lifespan of several model organisms by inducing autophagy. However, the effect of spermidine against neuronal damage has not yet been fully determined. In this study, neuronal cell injury was induced by treating PC12 cells and cortical neurons with 1 μM staurosporine (STS). We found that STS-induced cell injury could be efficiently attenuated by pretreatment with 1 mM spermidine. Spermidine inhibited the caspase 3 activation induced by STS. Moreover, STS incubation resulted in autophagic degradation failure, which could be attenuated by the pretreatment of spermidine. Knocking down the expression of Beclin 1 efficiently suppressed autophagosome and autolysosome accumulation, and abolished the protective effects of spermidine against STS-induced neurotoxicity. Increased Beclin 1 cleavage and partial nuclear translocation of Beclin 1 fragment was detected in STS-treated cells, which could be blocked by spermidine, pan-caspase inhibitor or caspase 3-specific inhibitor. The nuclear translocation of Beclin 1 fragment universally occurs in damaged neurons. Beclin 1 mutation at the sites of 146 and 149 prevented the intracellular re-distribution of Beclin 1 induced by STS. In addition, intraperitoneal injection of spermidine ameliorated ischemia/reperfusion-induced neuronal injury in the hippocampus and cortex of rats, possibly via blocking caspase 3 activation and consequent Beclin 1 cleavage. Our findings suggest that caspase 3-mediated Beclin 1 cleavage occurs in acute neuronal cell injury both in vitro and in vivo. The neuroprotective effect of spermidine may be related to inhibition of the caspase 3-mediated Beclin 1 cleavage and restoration of the Beclin 1-dependent autophagy.
authors.affiliation: Department of Pharmacology, Hangzhou Key Laboratory of Medical Neurobiology, School of Medicine, Hangzhou Normal University, Hangzhou, China.|Department of Biomedical Engineering, Zhejiang Provincial Key Laboratory of Cardio-Cerebral Vascular Detection Technology and Medicinal Effectiveness Appraisal, Zhejiang University, Hangzhou, China.
authors.forename: Yi
authors.initials: Y
authors.lastname: Yang
authors.affiliation: Department of Biomedical Engineering, Zhejiang Provincial Key Laboratory of Cardio-Cerebral Vascular Detection Technology and Medicinal Effectiveness Appraisal, Zhejiang University, Hangzhou, China.|Clinical Research Center, The 2nd Affiliated Hospital, Zhejiang University School of Medicine, Hangzhou, China.
authors.forename: Sicong
authors.initials: S
authors.lastname: Chen
authors.affiliation: Department of Pharmacology, Hangzhou Key Laboratory of Medical Neurobiology, School of Medicine, Hangzhou Normal University, Hangzhou, China.
authors.forename: Yuqing
authors.initials: Y
authors.lastname: Zhang
authors.affiliation: Department of Pharmacology, Hangzhou Key Laboratory of Medical Neurobiology, School of Medicine, Hangzhou Normal University, Hangzhou, China.
authors.forename: Xiaoxia
authors.initials: X
authors.lastname: Lin
authors.affiliation: Department of Pharmacology, Hangzhou Key Laboratory of Medical Neurobiology, School of Medicine, Hangzhou Normal University, Hangzhou, China.
authors.forename: Yiyin
authors.initials: Y
authors.lastname: Song
authors.affiliation: Department of Neurosurgery, Sir Run Run Shaw Hospital, Medical College of Zhejiang University, Hangzhou, China.
authors.forename: Zhaoliang
authors.initials: Z
authors.lastname: Xue
authors.affiliation: Department of General Surgery, Institute of Micro-Invasive Surgery of Zhejiang University, Sir Run Run Shaw Hospital, Medical College of Zhejiang University, Hangzhou, China.
authors.forename: Haoran
authors.initials: H
authors.lastname: Qian
authors.affiliation: Department of Pharmacology, Hangzhou Key Laboratory of Medical Neurobiology, School of Medicine, Hangzhou Normal University, Hangzhou, China.
authors.forename: Shanshan
authors.initials: S
authors.lastname: Wang
authors.affiliation: Department of Pharmacology, Hangzhou Key Laboratory of Medical Neurobiology, School of Medicine, Hangzhou Normal University, Hangzhou, China.
authors.forename: Guihua
authors.initials: G
authors.lastname: Wan
authors.affiliation: Department of Biomedical Engineering, Zhejiang Provincial Key Laboratory of Cardio-Cerebral Vascular Detection Technology and Medicinal Effectiveness Appraisal, Zhejiang University, Hangzhou, China.
authors.forename: Xiaoxiang
authors.initials: X
authors.lastname: Zheng
authors.affiliation: Department of Pharmacology, Hangzhou Key Laboratory of Medical Neurobiology, School of Medicine, Hangzhou Normal University, Hangzhou, China.
authors.forename: Lihui
authors.initials: L
authors.lastname: Zhang
mesh_terms: D000818:Animals; D001343:Autophagy / Q000187:drug effects* / Q000235:genetics; D000071186:Beclin-1 / Q000235:genetics / Q000378:metabolism*; D053148:Caspase 3 / Q000235:genetics / Q000378:metabolism*; D002540:Cerebral Cortex / Q000378:metabolism* / Q000473:pathology; D006624:Hippocampus / Q000378:metabolism* / Q000473:pathology; D009474:Neurons / Q000378:metabolism / Q000473:pathology; D018696:Neuroprotective Agents / Q000494:pharmacology*; D016716:PC12 Cells; D059748:Proteolysis / Q000187:drug effects*; D051381:Rats; D015427:Reperfusion Injury / Q000188:drug therapy / Q000235:genetics / Q000378:metabolism / Q000473:pathology; D013095:Spermidine / Q000494:pharmacology*
chemical_list: D000071186:Beclin-1; C512829:Becn1 protein, rat; D018696:Neuroprotective Agents; C505410:Casp3 protein, rat; D053148:Caspase 3; D013095:Spermidine