Biosynthesis, Characterization, and Efficacy in Retinal Degenerative Diseases of Lens Epithelium-derived Growth Factor Fragment (LEDGF1-326), a Novel Therapeutic Protein

For vision-threatening retinitis pigmentosa and dry age-related macular degeneration, there are no United States Food and Drug Administration (FDA)-approved treatments. We identified, biosynthesized, purified, and characterized lens epithelium-derived growth factor fragment (LEDGF(1-326)) as a novel protein therapeutic. LEDGF(1-326) was produced at about 20 mg/liter of culture when expressed in the Escherichia coli system, with about 95% purity and aggregate-free homogeneous population with a mean hydrodynamic diameter of 9 +/- 1 nm. The free energy of unfolding of LEDGF(1-326) was 3.3 +/- 0.5 kcal mol(-1), and melting temperature was 44.8 +/- 0.2 degrees C. LEDGF(1-326) increased human retinal pigment epithelial cell viability from 48.3 +/- 5.6 to 119.3 +/- 21.1% in the presence of P23H mutant rhodopsin-mediated aggregation stress. LEDGF(1-326) also increased retinal pigment epithelial cell FluoSphere uptake to 140 +/- 10%. Eight weeks after single intravitreal injection in Royal College of Surgeons (RCS) rats, LEDGF(1-326) increased the b-wave amplitude significantly from 9.4 +/- 4.6 to 57.6 +/- 8.8 mu V for scotopic electroretinogram and from 10.9 +/- 5.6 to 45.8 +/- 15.2 mu V for photopic electroretinogram. LEDGF(1-326) significantly increased the retinal outer nuclear layer thickness from 6.34 +/- 1.6 to 11.7 +/- 0.7 mu m. LEDGF(1-326) is a potential new therapeutic agent for treating retinal degenerative diseases.