COLCHICINE-INDUCED MODULATION OF COLLAGENASE IN HUMAN-SKIN FIBROBLAST-CULTURES .2. A PROBE FOR DEFECTIVE REGULATION IN EPIDERMOLYSIS BULLOSA

[摘要] The addition of colchicine to cultures of normal human skin fibroblasts produces a significant stimulation of collagenase. Because this finding implies a role for the microtubule system in the regulation of normal collagenase synthesis, colchicine was used as a probe for aberrations in this enzymne in epidermolysis bullosa. In fibroblast cultures from the dominant simplex, dominant dystrophic and recessive letalis forms of epidermolysis bullosa, 10-6 M colchicine produced approximately a 2-fold increase in collagenase in the culture medium, a finding shown by biosynthetic studies to be attributable to enhanced synthesis of enzyme protein. In the case of typical recessive dystrophic epidermolysis bullosa, a disease characterized by excessive collagenase synthesis, the fibroblasts could also be stimulated to produce additional collagenase, despite having elevated baseline synthetic rates. Fibroblasts isolated from 1 recessive epidermolysis bullosa [REB] patient were resistant to the stimulatory effects of colchicine in concentrations up to 5 .times. 10-6 M. In the absence of colchicine, collagenase synthesis in this patient''s cells (termed REBc-) was 3-4 times that of normal controls, suggesting that the as yet undefined cellular function that is abrogated (or stimulated) by colchicine in normal cells may have been genetically impaired in these REBc- cells. Despite the resistance to colchicine, as manifested by the failure to stimulate collagenase, gross parameters of microtubular function, such as cell replication, were intact. Phenotypically, this patient had a form of epidermolysis bullosa intermediate between typical recessive dystrophic and recessive letalis forms of the disease. Although an experimentally induced blister was located in the lamina lucida, hypoplastic anchoring fibrils were also observed. These findings, in addition to the marked increase in collagenase synthesis, suggest the possibility that this patient may represent a compound heterozygote of 2 forms of epidermolysis bullosa and that colchicine may be useful in defining other such patients.