title: Doxycycline-regulated GDNF expression promotes axonal regeneration and functional recovery in transected peripheral nerve.
abstract: Increased production of neurotrophic factors (NTFs) is one of the key responses seen following peripheral nerve injury, making them an attractive choice for pro-regenerative gene therapies. However, the downside of over-expression of certain NTFs, including glial cell line-derived neurotrophic factor (GDNF), was earlier found to be the trapping and misdirection of regenerating axons, the so-called 'candy-store' effect. We report a proof-of-principle study on the application of conditional GDNF expression system in injured peripheral nerve. We engineered Schwann cells (SCs) using dendrimers or lentiviral transduction with the vector providing doxycycline-regulated GDNF expression. Injection of GDNF-modified cells into the injured peripheral nerve followed by time-restricted administration of doxycycline demonstrated that GDNF expression in SCs can also be controlled locally in the peripheral nerves of the experimental animals. Cell-based GDNF therapy was shown to increase the extent of axonal regeneration, while controlled deactivation of GDNF effectively prevented trapping of regenerating axons in GDNF-enriched areas, and was associated with improved functional recovery.
authors.affiliation: Department of Clinical Neuroscience, Faculty of Medicine, University of Calgary, Calgary, Canada; Hotchkiss Brain Institute, University of Calgary, Calgary, Canada. Electronic address: shakhbazau@gmail.com.
authors.forename: Antos
authors.initials: A
authors.lastname: Shakhbazau
authors.forename: Chandan
authors.initials: C
authors.lastname: Mohanty
authors.forename: Dzmitry
authors.initials: D
authors.lastname: Shcharbin
authors.forename: Maria
authors.initials: M
authors.lastname: Bryszewska
authors.forename: Anne-Marie
authors.initials: AM
authors.lastname: Caminade
authors.forename: Jean-Pierre
authors.initials: JP
authors.lastname: Majoral
authors.forename: Jacob
authors.initials: J
authors.lastname: Alant
authors.forename: Rajiv
authors.initials: R
authors.lastname: Midha
mesh_terms: D000818:Animals; D000900:Anti-Bacterial Agents / Q000627:therapeutic use*; D060846:Cell Engineering; D002478:Cells, Cultured; D004318:Doxycycline / Q000627:therapeutic use*; D005786:Gene Expression Regulation / Q000187:drug effects*; D051100:Glial Cell Line-Derived Neurotrophic Factor / Q000235:genetics* / Q000378:metabolism; D057809:HEK293 Cells; D006801:Humans; D016086:Lentivirus / Q000235:genetics; D008297:Male; D009416:Nerve Regeneration; D059348:Peripheral Nerve Injuries / Q000235:genetics / Q000378:metabolism / Q000503:physiopathology / Q000628:therapy*; D010525:Peripheral Nerves / Q000378:metabolism / Q000502:physiology / Q000503:physiopathology; D051381:Rats; D011917:Rats, Inbred Lew; D020127:Recovery of Function; D012583:Schwann Cells / Q000166:cytology / Q000378:metabolism / Q000637:transplantation*
chemical_list: D000900:Anti-Bacterial Agents; D051100:Glial Cell Line-Derived Neurotrophic Factor; D004318:Doxycycline
keywords: Conditional expression; DiI (PubChem CID 2762626); Doxycycline; Doxycycline (PubChem CID 54686183); Forskolin (PubChem CID 47936); GDNF; Lentivirus; MTT (PubChem CID 64965); Peripheral nerve; Regeneration