Springer Verlag, AGE, 4(31), p. 365-372, 2009
DOI: 10.1007/s11357-009-9111-6
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Aging in human skin is the composite of time-dependent intrinsic aging plus photoaging induced by chronic exposure to ultraviolet radiation. Nuclear hormone receptors coordinate diverse processes including metabolic homeostasis. Liver X receptor beta (LXRbeta) is a close human homologue of daf-12, a regulator of nematode longevity. LXRbeta is positively regulated by sirtuin-1 and resveratrol, while LXRbeta-null mice show transcriptional profiles similar to those seen in aged human skin. In these studies, we examined LXRbeta expression in aged and photoaged human skin. Volunteers were recruited to assess intrinsic aging and photoaging. Epidermal LXRbeta mRNA was examined by in situ hybridization while protein was identified by immunofluorescence. No significant changes were observed in either LXRbeta mRNA or protein expression between young and aged volunteers (mRNA p = 0.90; protein p = 0.26). Similarly, LXRbeta protein expression was unaltered in photoaged skin (p = 0.75). Our data therefore suggest that, while not playing a major role in skin aging, robust cutaneous expression implies a fundamental role for LXRbeta in epidermal biology.