Flightless I Expression Enhances Murine Claw Regeneration Following Digit Amputation.
The mammalian digit tip is capable of both reparative and regenerative wound healing dependent on the level of amputation injury. Removal of the distal third of the terminal phalange results in successful regeneration, whereas a more severe, proximal, amputation heals by tissue repair. Flightless I (Flii) is involved in both tissue repair and regeneration. It negatively regulates wound repair but elicits a positive effect in hair follicle regeneration, with Flii overexpression resulting in significantly longer hair fibers. Using a model of digit amputation in Flii overexpressing (FIT) mice, we investigated Flii in digit regeneration. Both wild-type and FIT digits regenerated after distal amputation with newly regenerated FIT claws being significantly longer than intact controls. No regeneration was observed in wild-type mice after severe proximal amputation; however, FIT mice showed significant regeneration of the missing digit. Using a three-dimensional model of nail formation, connective tissue fibroblasts isolated from the mesenchymal tissue surrounding the wild-type and FIT digit tips and cocultured with skin keratinocytes demonstrated aggregate structures resembling rudimentary nail buds only when Flii was overexpressed. Moreover, β-catenin and cyclin D1 expression was maintained in the FIT regenerating germinal matrix suggesting a potential interaction of Flii with Wnt signaling during regeneration.
Future Industries Institute, University of South Australia, Mawson Lakes, South Australia, Australia. Electronic address: xanthe.strudwick@unisa.edu.au.
Xanthe L
XL
Strudwick
Women's and Children's Health Research Institute, North Adelaide, South Australia, Australia.
James M
JM
Waters
Future Industries Institute, University of South Australia, Mawson Lakes, South Australia, Australia.
Allison J
AJ
Cowin
D000671:Amputation, Surgical / Q000379:methods*; D000818:Animals; D001707:Biopsy, Needle; D002352:Carrier Proteins / Q000235:genetics*; D004195:Disease Models, Animal; D005786:Gene Expression Regulation; D006724:Hoof and Claw / Q000502:physiology / Q000601:surgery*; D007150:Immunohistochemistry; D051379:Mice; D008807:Mice, Inbred BALB C; D008822:Mice, Transgenic; D008840:Microfilament Proteins; D011897:Random Allocation; D012038:Regeneration / Q000235:genetics*; D015534:Trans-Activators; D014945:Wound Healing / Q000235:genetics / Q000502:physiology; D051176:beta Catenin / Q000378:metabolism
D002352:Carrier Proteins; C000609263:FlII protein, mouse; D008840:Microfilament Proteins; D015534:Trans-Activators; D051176:beta Catenin