Glaucoma is one of the leading causes of blindness in the world. This chronic and progressive optic neuropathy is characterized by loss of axons of the retinal ganglion cells (RGC) that constitute the optic nerve. Nerve growth factor (NGF) binds to both tyrosine kinase receptor TrkA and receptor P75NTR (TNF receptor superfamily). Importantly, the binding of NGF to TrkA alone promotes RGC’s survival and proliferation. In contrast, binding of NGF to p75NTR leads to apoptosis. rNGF (recombinant NGF) is currently produced in non-human cell systems. Due to the importance of pro-sequence for efficient folding or refolding, the in vitro or in vivo post-proteolytic modifications of pro-NGF, and the requirement of forming disulfide bonded monomer and non-covalent homodimer, expression yields from current manufacturing process are low and the NGF protein was in low quality. 

We have developed a cost-effective and scalable expression system to produce therapeutic human proteins from a proprietary HEK293 cell line. In the preliminary studies, we have established a cell pool of NGF which exhibited >10-fold higher yield than current expression systems with the ex vivo activity comparable to that of the murine wildtype NGF. We are optimizing the NGF to selectively activate TrkA receptor without compromising the expression yield or protein stability. We will then select top stable HEK293 cell clones for TrkA selective NGF mutant, which will be suitable for future large-scale cGMP manufacturing. Since there are substantial similarities between the rodent and human eyes, we will validate the efficacy and safety in an established rat model of glaucoma.