Expression of cytosolic retinoid-binding protein genes in human skin biopsies and cultured keratinocytes and fibroblasts

Summary Using reverse transcription coupled to polymerase chain reaction we have studied the mRNA expression of serum retinol-binding protein and cytosolic receptors for retinol and retinoic acid in skin biopsies, and in cultured epidermal keratinocytes and dermal fibroblasts. Transcripts for cellular retinol-binding protein (CRBP) I and cellular retinoic-acid-binding protein (CRABP) I were found in normal skin, keratinocytes, and fibroblasts. CRABP II transcripts were detected in skin and keratinocytes. A decreased mRNA expression of CRABP I and an increased mRNA expression of CRABP II were found in lesional psoriatic skin compared with uninvolved skin, mRNA transcripts for serum retinol-binding protein (s-RBP) were detected in all tissues and cells. The biological importance of s-RBP expression in keratinocytes and fibroblasts is not known, but hypothetically this protein may be involved in the intracellular shuttling of retinol and retinoic acid, or in the retransportation of cellular retinoids into the extracellular space.