Effect of heme and heme oxygenase-1 on vascular endothelial growth factor synthesis and angiogenic potency of human keratinocytes.
BACKGROUND
Skin injury leads to the release of heme, a potent prooxidant which is degraded by heme oxygenase-1 (HO-1) to carbon monoxide, iron, and biliverdin, subsequently reduced to bilirubin. Recently the involvement of HO-1 in angiogenesis has been shown; however, the role of heme and HO-1 in wound healing angiogenesis has not been yet investigated.


RESULTS
Treatment of HaCaT keratinocytes with hemin (heme chloride) induced HO-1 expression and activity. The effect of heme on vascular endothelial growth factor (VEGF) synthesis is variable: induction is significant after a short, 6 h treatment with heme, while longer stimulation may attenuate its production. The involvement of HO-1 in VEGF synthesis was confirmed by inhibition of VEGF expression by SnPPIX, a blocker of HO activity and by attenuation of HO-1 mRNA expression with specific siRNA. Importantly, induction of HO-1 by hemin was able to overcome the inhibitory effect of high glucose on VEGF synthesis. Moreover, HO-1 expression was also induced in keratinocytes cultured in hypoxia, with concomitant augmentation of VEGF production, which was further potentiated by hemin stimulation. Accordingly, conditioned media from keratinocytes overexpressing HO-1 enhanced endothelial cell proliferation and augmented formation of capillaries in angiogenic assay in vitro.


CONCLUSIONS
HO-1 is involved in hemin-induced VEGF expression in HaCaT and may play a role in hypoxic regulation of this protein. HO-1 overexpression may be beneficial in restoring the proper synthesis of VEGF disturbed in diabetic conditions.
Jazwa
Agnieszka
A
Department of Medical Biotechnology, Faculty of Biotechnology, Jagiellonian University, Gronostajowa 7, 30-387 Krakow, Poland.
Loboda
Agnieszka
A
Golda
Slawomir
S
Cisowski
Jaroslaw
J
Szelag
Magdalena
M
Zagorska
Anna
A
Sroczynska
Patrycja
P
Drukala
Justyna
J
Jozkowicz
Alicja
A
Dulak
Jozef
J
D049109:Cell Proliferation / Q000187:drug effects; D002478:Cells, Cultured; D017077:Culture Media, Conditioned / Q000494:pharmacology; D004730:Endothelium, Vascular / Q000166:cytology; D005609:Free Radicals / Q000378:metabolism; D005947:Glucose / Q000494:pharmacology; D051547:Heme Oxygenase-1 / Q000494:pharmacology*; D006427:Hemin / Q000494:pharmacology*; D006801:Humans; D000860:Hypoxia / Q000378:metabolism; D015603:Keratinocytes / Q000378:metabolism*; D018919:Neovascularization, Physiologic / Q000502:physiology*; D011401:Promoter Regions, Genetic / Q000187:drug effects; D034741:RNA, Small Interfering / Q000494:pharmacology; D042461:Vascular Endothelial Growth Factor A / Q000096:biosynthesis*; D014945:Wound Healing / Q000502:physiology
D017077:Culture Media, Conditioned; D005609:Free Radicals; D034741:RNA, Small Interfering; C467484:VEGFA protein, human; D042461:Vascular Endothelial Growth Factor A; D006427:Hemin; D051547:Heme Oxygenase-1; D005947:Glucose