ANTI-INFLAMMATORY STEROIDS AND COLLAGEN SYNTHESIS

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Anti-inflammatory steroids are used in various dermatological diseases. One of the most conspicuous side effects of these steroids is skin atrophy. In the past granting periods we have shown that anti-inflammatory steroids selectively decrease type I procollagen synthesis and decrease mRNAs for both pro Alpha1(I) and pro Alpha2(I) in chick skin and in chick skin fibroblasts. We now propose to determine the effects of anti-inflammatory steroids on type I procollagen mRNA's in nuclei, in the cytoplasm and in polysomes by using cloned cDNA probes for procollagen pro Alpha1(I) and pro Alpha2(I) mRNA's. The effects of glucocorticoids on the turnover rates of type I procollagen mRNAs in the cytoplasm will be determined. The effect of glucocorticoid on the transcription of type I procollagen nuclear RNA will also be determined. Nuclei will be isolated from control and steroid treated fibroblasts and transcribed in vitro. Nuclei isolated from control fibroblasts will be incubated with activated glucocorticoid-receptor in vitro and transcription of type I procollagen genes will be determined. The effect of the activated glucocorticoid-receptor on polyadenylation and splicing of type I procollagen nuclear RNA will also be accessed. Furthermore, nuclei from control and glucocorticoid treated chick skin fibroblasts will be assayed for poly(A)polymerase activity. We will determine the degree of binding of the steroid-receptor to a 5 feet procollagen cloned gene fragment which has been successfully transcribed in vitro. The ability of the steroid-receptor to regulate the synthesis of procollagen type I transcripts by this gene fragment will be accessed. We will also determine the ability of two novel prednisolone ester derivatives, methylprednisolonate and methyl 20 dihydroprednisolonate, to inhibit bleomycin-induced collagen synthesis in chick skin and in chick skin fibroblasts. We are particularly excited about these new steroids since they are anti-inflammatory but do not inhibit normal skin collagen synthesis. These studies will provide a molecular basis for glucocorticoid inhibition of procollagen synthesis in skin.