RETINOIC ACID UP-REGULATES CILIARY NEUROTROPHIC FACTOR RECEPTORS IN CULTURED CHICK NEURONS AND CARDIOMYOCYTES

Retinoic acid is an important developmental factor in the heart and ne rvous system and regulates the expression of trophic factor receptors in neural cell lines. Here we show the effects of retinoic acid on cyt okine responsiveness in embryonic chick neurons and myocytes. Treatmen t of cultured cardiomyocytes and retinal and ciliary ganglion neurons with retinoic acid resulted in increased expression of receptors for t he neuropoietic cytokine, CNTF. All-trans-retinoic acid induced as muc h as a 3-fold increase in CNTF receptor alpha subunit mRNA in a time a nd concentration dependent manner and resulted in an enhanced CNTF-ind uced tyrosine phosphorylation of the transcription factor, STAT3. Thes e results indicate that neurons and myocytes expressing CNTF receptors are responsive to retinoic acid and suggest that retinoids may regula te cell sensitivity to cytokines during development. (C) 1998 Elsevier Science Ireland Ltd.