title: Cycloastragenol is a potent telomerase activator in neuronal cells: implications for depression management.
abstract: Cycloastragenol (CAG) is an aglycone of astragaloside IV. It was first identified when screening Astragalus membranaceus extracts for active ingredients with antiaging properties. The present study demonstrates that CAG stimulates telomerase activity and cell proliferation in human neonatal keratinocytes. In particular, CAG promotes scratch wound closure of human neonatal keratinocyte monolayers in vitro. The distinct telomerase-activating property of CAG prompted evaluation of its potential application in the treatment of neurological disorders. Accordingly, CAG induced telomerase activity and cAMP response element binding (CREB) activation in PC12 cells and primary neurons. Blockade of CREB expression in neuronal cells by RNA interference reduced basal telomerase activity, and CAG was no longer efficacious in increasing telomerase activity. CAG treatment not only induced the expression of bcl2, a CREB-regulated gene, but also the expression of telomerase reverse transcriptase in primary cortical neurons. Interestingly, oral administration of CAG for 7 days attenuated depression-like behavior in experimental mice. In conclusion, CAG stimulates telomerase activity in human neonatal keratinocytes and rat neuronal cells, and induces CREB activation followed by tert and bcl2 expression. Furthermore, CAG may have a novel therapeutic role in depression.
authors.affiliation: Division of Life Science, The Hong Kong University of Science and Technology, Hong Kong, China.
authors.forename: Fanny C F
authors.initials: FC
authors.lastname: Ip
authors.forename: Yu Pong
authors.initials: YP
authors.lastname: Ng
authors.forename: H J
authors.initials: HJ
authors.lastname: An
authors.forename: Ying
authors.initials: Y
authors.lastname: Dai
authors.forename: Hai Hong
authors.initials: HH
authors.lastname: Pang
authors.forename: Yue Qing
authors.initials: YQ
authors.lastname: Hu
authors.forename: Allison C
authors.initials: AC
authors.lastname: Chin
authors.forename: Calvin B
authors.initials: CB
authors.lastname: Harley
authors.forename: Yung Hou
authors.initials: YH
authors.lastname: Wong
authors.forename: Nancy Y
authors.initials: NY
authors.lastname: Ip
mesh_terms: D000818:Animals; D000928:Antidepressive Agents / Q000008:administration & dosage; D017362:Cyclic AMP Response Element-Binding Protein / Q000378:metabolism; D003863:Depression / Q000188:drug therapy*; D006801:Humans; D015603:Keratinocytes / Q000187:drug effects / Q000378:metabolism; D051379:Mice; D020932:Nerve Growth Factor / Q000378:metabolism; D009474:Neurons / Q000187:drug effects* / Q000378:metabolism*; D016716:PC12 Cells; D019253:Proto-Oncogene Proteins c-bcl-2 / Q000378:metabolism; D051381:Rats; D012502:Sapogenins / Q000008:administration & dosage* / Q000138:chemical synthesis; D019098:Telomerase / Q000378:metabolism*
chemical_list: D000928:Antidepressive Agents; D017362:Cyclic AMP Response Element-Binding Protein; D019253:Proto-Oncogene Proteins c-bcl-2; D012502:Sapogenins; D020932:Nerve Growth Factor; D019098:Telomerase; C061014:cycloastragenol