INCREASING MEMBRANE REPAIR AS A NOVEL THERAPEUTIC APPROACH IN THE TREATMENT OF MYOSITIS

Myositis is an idiopathic autoimmune disorder characterized by severe skeletal muscle inflammation and degeneration. Treatment is limited to systemic immunological suppression and development of future therapeutic strategies are contingent upon the elucidation of pathogenic mechanisms. Recent studies under Dr. Noah Weisleder at The Ohio State University show that muscle antigen exposure due to compromised membrane resealing accompanies myositis progression. TRIM72 is a critical facilitator of the membrane resealing process and has been identified as a novel myositis specific autoantigen (MSA). TRIM72 proteins may act as autoantigens following membrane injury, resulting in TRIM72 autoantibodies that compromise membrane resealing and increase inflammation. Using an indirect ELISA, myositis patient sera was screened for increased levels of TRIM 72 antibodies. Patient sera positive for high levels of TRIM72 antibodies (> 1 standard deviation) will be tested for membrane resealing capacity using a glass bead damage assay and human embryonic kidney (HEK) cells. Readout is intracellular lactate dehydrogenase (LDH) release after membrane injury. F urther experiments will utilize a multiphoton infrared laser injury assay and a lipophilic dye that fluoresces only when exposed to membrane phospholipids to quantify cellular membrane damage in the presence of positive patient sera. If TRIM72 autoantibodies prove to be crucial in myositis associated membrane-resealing impairment, it presents a potential therapeutic target. Exogenous poloxamer 188 (P188) is proven to enhance membrane-resealing capacity in muscle membranes. Later laser injury assays will be performed in the presence of P188 to investigate if there is an improvement in myositis related membrane resealing capacity.