Human lactoferrin stimulates skin keratinocyte function and wound re-epithelialization.
BACKGROUND
Human lactoferrin (hLF), a member of the transferrin family, is known for its antimicrobial and anti-inflammatory effects. Recent studies on various nonskin cell lines indicate that hLF may have a stimulatory effect on cell proliferation.


OBJECTIVE
To study the potential role of hLF in wound re-epithelialization.


METHODS
The effects of hLF on cell growth, migration, attachment and survival were assessed, with a rice-derived recombinant hLF (holo-rhLF), using proliferation analysis, scratch migration assay, calcein-AM/propidium iodide staining and terminal deoxynucleotidyl transferase-mediated dUTP nick-end labelling (TUNEL) method, respectively. The mechanisms of hLF on cell proliferation and migration were explored using specific pathway inhibitors. The involvement of lactoferrin receptor low-density lipoprotein receptor-related protein 1 (LRP1) was examined with RNA interference technique. An in vivo swine second-degree burn wound model was also used to assess wound re-epithelialization.


RESULTS
Studies revealed that holo-rhLF significantly stimulated keratinocyte proliferation which could be blocked by mitogen-activated protein kinase (MAPK) kinase 1 inhibitor. Holo-rhLF also showed strong promoting effects on keratinocyte migration, which could be blocked by either inhibition of the MAPK, Src and Rho/ROCK pathways, or downregulation of the LRP1 receptor. With cells under starving or 12-O-tetradecanoylphorbol-13-acetate exposure, the addition of holo-rhLF was found greatly to increase cell viability and inhibit cell apoptosis. Additionally, holo-rhLF significantly increased the rate of wound re-epithelialization in swine second-degree burn wounds.


CONCLUSIONS
Our studies demonstrate the direct effects of holo-rhLF on wound re-epithelialization including the enhancement of keratinocyte proliferation and migration as well as the protection of cells from apoptosis. The data strongly indicate its potential therapeutic applications in wound healing.
Tang
L
L
Department of Dermatology and Cutaneous Surgery, University of Miami Miller School of Medicine, Miami, FL 33136, USA.
Wu
J J
JJ
Ma
Q
Q
Cui
T
T
Andreopoulos
F M
FM
Gil
J
J
Valdes
J
J
Davis
S C
SC
Li
J
J
D000818:Animals; D017209:Apoptosis / Q000187:drug effects; D049109:Cell Proliferation / Q000187:drug effects*; D006801:Humans; D015603:Keratinocytes / Q000187:drug effects* / Q000378:metabolism; D007781:Lactoferrin / Q000494:pharmacology*; D012275:Oryza; D011994:Recombinant Proteins / Q000494:pharmacology; D012867:Skin / Q000166:cytology; D013552:Swine; D014945:Wound Healing / Q000187:drug effects*
D011994:Recombinant Proteins; D007781:Lactoferrin