CELLULAR RETINOL-BINDING PROTEIN-1 IS TRANSIENTLY EXPRESSED IN GRANULATION-TISSUE FIBROBLASTS AND DIFFERENTIALLY EXPRESSED IN FIBROBLASTS CULTURED FROM DIFFERENT ORGANS

We have reported that cellular retinol-binding protein-1 (CRBP-1) is t ransiently expressed by arterial smooth muscle cells during experiment al intimal repair (P. Neuville, A. Geinoz, G. Benzonana, M. Redard, F. Gabbiani, F. Ropraz, G. Gabbiani: Am J Pathol 1997, 150:509-521). We have examined here the expression of CRBP-1 during wound healing after a full-thickness rat skin wound, CRBP-1 was transiently expressed by a significant proportion of fibroblastic cells including myofibroblast s. Expression started 4 days after wounding, reached a maximum at 12 d ays, and persisted up to 30 days when a scar was formed. After wound c losure, most CRBP-l-containing fibroblastic cells underwent apoptosis, We have further investigated CRBP-1 expression in rat fibroblasts cul tured from different organs, CRBP-I was abundant in lung and heart fib roblasts and was detected in decreasing amounts in muscle, tendon, sub cutaneous tissue, and granulation tissue fibroblasts, Dermis fibroblas ts contained no detectable levels of CRBP-1, All-trans retinoic acid a nd transforming growth factor-beta 1 inhibited cell proliferation and increased CRBP-1 expression in fibroblastic populations except dermis fibroblasts, We demonstrate that during granulation tissue formation a subpopulation of fibroblastic cells express CRBP-1 ne novo, We also d emonstrate that CRBP-1 expression by fibroblasts is regulated in vitro by retinoic acid and transforming growth factor-beta 1 Our results su ggest that CRBP-1 and possibly retinoic acid play a role in the evolut ion of granulation tissue.