Retinoic acid upregulates c-kit ligand production by murine keratinocyte in vitro and increases cutaneous mast cell in vivo

Abstract

Mouse-transformed epidermal cell line (Pam 212) generated the soluble mediators for promoting the growth of a mast cell line (MC9) in the presence of retinoic acid at a concentration of 10(-6)-10(-7) M. The effective molecule of MC9 cell growth promoting factor (MC9-GF) was non-dialyzable and eluted between the molecular weight of 45 K and 68 K on a TSK 2000 G column. Chromatofocusing analysis revealed that this factor had a pI range between 7.0 and 7.5. Anti-c-kit ligand antibody abrogated MC9-GF activity and RT-PCR analysis demonstrated that retinoic acid upregulates c-kit ligand mRNA expression by Pam cells. Several recombinant cytokines including IL1-alpha, IL-1 beta, IL-2, IL-3 or IL-4 did not promote MC9 cell growth at a concentration of 100 U/ml. The presence of anti-IL-1 alpha, -IL-1 beta, -IL-2, -IL-3 or -IL-4 antibodies did not abrogate the MC9-GF activity except for anti-c-kit ligand antibody.