Retinoic acid is a negative regulator for the differentiation of cord blood-derived human mast cell progenitors

We examined the effects of retinoids on the human mast cell development usi ng a serum-deprived culture system. When 10-week cultured mast cells derive d from CD34(+) cord blood cells were used as target cells, both all-trans r etinoic acid (ATRA) and 9-cis RA inhibited the progeny generation under sti mulation with stem cell factor (SCF) in a dose-dependent manner (the number of progeny grown by SCF plus RA at 10(-7) mol/L was one tenth of the value obtained by SCF alone). The early steps in mast cell development appear to be less sensitive to RA according to the single CD34(+)c-kit(+) cord blood cell culture study. The optimal concentration of RAs also reduced the hist amine concentration in the cultured mast cells (3.00 +/- 0.47 pg per cell i n SCF alone, 1.44 +/- 0.18 pg per cell in SCF+ATRA, and 1.41 +/- 0.10 pg pe r cell in SCF + 9-cis RA), RT-PCR analyses showed the expression of RAR alp ha, RAR beta, RXR alpha, and RXR beta messenger ribonucleic acid (mRNA) in 10-week cultured mast cells. The addition of an RAR-selective agonist at 10 (-10) mol/L to 10(-7) mol/L decreased the number of mast cells grown in SCF , whereas an RXR-selective agonist at up to 10(-8) mol/L was inactive. Amon g RAR subtype selective retinoids used at 10(-9) mol/L to 10(-7) mol/L, onl y the RAR alpha agonist was equivalent to ATRA at 10(-7) mol/L in its abili ty to inhibit mast cell growth. Conversely, the addition of excess concentr ations of a RAR alpha antagonist profoundly counteracted the retinoid-media ted suppressive effects. These results suggest that RA inhibits SCF-depende nt differentiation of human mast cell progenitors through a specific recept or. (Blood. 2000;95:2821-2828) (C) 2000 by The American Society of Hematolo gy.