Macrophage inhibitory cytokine MIC‐1 is upregulated by short‐wavelength light in cultured normal human dermal fibroblasts

Abstract

To better understand dermal response to visible light, we used DNA microarray analysis to search genes induced by blue or near‐UV light in normal human dermal fibroblasts. Of about 12 800 transcripts analyzed, near‐UV light most prominently upregulated the transcript level of Mic‐1, a gene encoding a TGF‐β superfamily protein. Quantitative RT‐PCR and immunoblot analyses revealed that mRNA and protein levels of Mic‐1 were upregulated by both short‐wavelength light but not by green or red light. These results suggest that the human dermis is a site for macrophage inhibitory cytokine‐1 (MIC‐1) production and that visible light activates a dermal transcription cascade. Considering the role of MIC‐1 in immune regulation and appetite control, photic MIC‐1 regulation is of physiological importance.