PMC

HO-1 overexpression protects cells from undergoing UV-induced apoptosis. COS cells were transfected with HO-1 and HO-2 expression plasmids and exposed to 1 J/cm² UV-B. Viability was measured by MTT assay after 48 h.

HO-1 expressed in skin repigmenting in response to PUVA treatment. HO-1 staining of skin biopsies from vitiligo (a) lesional skin before, and (b) from repigmented skin within 1 h, after 13 weeks of 3x/week PUVA treatment, total dose 100 J/cm². Red arrows: marked HO-1 expression. Blue arrows: TRP-1 expression restricted to melanocytes. Brown arrows: nuclear capping by melanin.

Confocal microscopy of cultured human skin treated with UVA. Skin before and after 1.5 J/cm² UVA was immunostained with (a, e) anti-HO-1 antibody and (b, f) anti-TRP-1 antibody, and (c, g) DAPI. In (d, h) overlays are shown. (a–d) untreated skin. (e–h) 24 h after UVA treatment. Arrows point to the same cells under (a)–(d) and under (e)–(h).

HO-1 expression is upregulated and HO-2 expression reduced in response to UVA in organotypic culture. Expression of HO-1 in the basal epidermal layer of neonatal skin (a) untreated skin and (b) after single exposure to 400 mJ/m² UVA. Comparison between expression of HO-2 in (c) the epidermis of untreated neonatal skin and (d) 24 h after UVA. HO is shown in red and TRP-1 is shown in blue. Arrows: melanocytes.