Topical sonic hedgehog gene therapy accelerates wound healing in diabetes by enhancing endothelial progenitor cell-mediated microvascular remodeling.
BACKGROUND
Sonic hedgehog (Shh) is a prototypical morphogen known to regulate epithelial-mesenchymal interaction during embryonic development. Recent observations indicate that exogenous administration of Shh can induce angiogenesis and may accelerate repair of ischemic myocardium and skeletal muscle. Because angiogenesis plays a pivotal role in wound repair, we hypothesized that activation of the hedgehog pathway may promote a favorable effect on microvascular remodeling during cutaneous wound healing and thereby accelerate wound closure. Because diabetes is associated with impaired wound healing, we tested this hypothesis in a diabetic model of cutaneous wound repair.


RESULTS
In Ptc1-LacZ mice, cutaneous injury resulted in LacZ expression, indicating that expression of the Shh receptor Patched was induced and therefore that the Shh signaling pathway was intact postnatally and upregulated in the process of wound repair. In diabetic mice, topical gene therapy with the use of naked DNA encoding for Shh resulted in significant local gene expression and acceleration of wound recovery. The acceleration in wound healing was notable for increased wound vascularity. In bone marrow transplantation models, the enhanced vascularity of the wound was shown to be mediated, at least in part, by enhanced recruitment of bone marrow-derived endothelial progenitor cells. In vitro, Shh promoted production of angiogenic cytokines from fibroblasts as well as proliferation of dermal fibroblasts. Furthermore, Shh directly promoted endothelial progenitor cell proliferation, migration, adhesion, and tube formation.


CONCLUSIONS
These findings suggest that a simple strategy of topically applied Shh gene therapy may have significant therapeutic potential for enhanced wound healing in patients with impaired microcirculation such as occurs in diabetes.
Asai
Jun
J
Division of Cardiovascular Research and Medicine, St Elizabeth's Medical Center, Tufts University School of Medicine, Boston, MA, USA.
Takenaka
Hideya
H
Kusano
Kengo F
KF
Ii
Masaaki
M
Luedemann
Corinne
C
Curry
Cynthia
C
Eaton
Elizabeth
E
Iwakura
Atsushi
A
Tsutsumi
Yoshiaki
Y
Hamada
Hiromichi
H
Kishimoto
Saburo
S
Thorne
Tina
T
Kishore
Raj
R
Losordo
Douglas W
DW
D042501:Angiogenic Proteins / Q000235:genetics; D000818:Animals; D001483:Base Sequence; D017931:DNA Primers; D003921:Diabetes Mellitus, Experimental / Q000503:physiopathology*; D004195:Disease Models, Animal; D004730:Endothelium, Vascular / Q000502:physiology*; D015316:Genetic Therapy / Q000379:methods; D053823:Hedgehog Proteins; D051379:Mice; D008822:Mice, Transgenic; D008833:Microcirculation / Q000502:physiology*; D015534:Trans-Activators / Q000235:genetics*; D014945:Wound Healing / Q000502:physiology*
D042501:Angiogenic Proteins; D017931:DNA Primers; D053823:Hedgehog Proteins; D015534:Trans-Activators