Cicatricial pemphigoid is a blinding, autoimmune disease of the ocular surface, mucous membranes and skin. Ocular manifestations are the result of pathologic fibrosis, with bands of conjunctival scar tissue binding the eye lids to the globe; conjunctival scarring and contraction rotating the eye lashed inward to rub against the cornea; subepithelial fibrosis obliterating the lacrimal gland orifices leading to dry eyes; and scarring and opacification of the cornea. Dense connective tissue and activated fibroblasts are observed during histologic and ultrastructural examination of conjunctiva from patients with cicatricial pemphigoid. The conjunctival changes of cicatricial pemphigoid are believed to result from binding of circulating antibodies against the conjunctival basement membrane with fixation of complement and formation of an inflammatory infiltrate in the subepithelial tissue which leads by an unknown mechanism to pathologic scarring. Scar tissue is an aberrant extracellular matrix produced by fibroblasts. In diseases characterized by abnormal fibrosis such as scleroderma, keloid, progressive nodular fibrosis of the skin and sclerosing basal cell carcinoma, increased expression of collagen genes by fibroblasts has been found. Conjunctival fibroblasts from patients with cicatricial pemphigoid have been shown to be hyperproliferative in vitro. The process of normal cellular proliferation involves the expression of genes known as proto- oncogenes. The changes in cell proliferation and extracellular matrix seen in cicatricial pemphigoid suggest that the fibroblasts are phenotypically abnormal, secondary perhaps to altered gene expression. Our long term goals are to establish the cellular and molecular basis of the pathogenesis of cicatricial pemphigoid.
The aim of this proposal is to test the hypothesis that the pathologic changes are due to altered gene expression. Consequently the specific aims of this proposal are to: 1) Identify the proto-oncogenes expressed in conjunctival fibroblasts from normals and patients with cicatricial pemphigoid. Fibroblasts from normals and patients with cicatricial pemphigoid will be grown in tissue culture and total cellular RNA will be extracted. RNA will be run on a formaldehyde agarose gel and Northern blot analysis will be performed using cDNA probes to proto-oncogenes and extracellular matrix protein genes. Gene expression will be quantified by examining autoradiographies. By understanding the cellular and molecular basis of the pathologic scarring responsible for the blinding and painful symptoms of cicatricial pemphigoid, we may be able to develop safe and effective new therapies.
