Research Areas

Gene Therapy for Diabetic Corneal Stem Cells

Delayed wound healing, erosions, and keratitis — the most serious complications of diabetes in the cornea — are treated only symptomatically. The Ljubimov Laboratory has described a number of markers altered in diabetic corneas. Using adenoviral gene therapy, the lab has been able to correct aberrant wound healing and several marker protein expression abnormalities in human organ-cultured diabetic corneas.

Researchers in the Ljubimov Lab have also documented that the expression of epithelial stem cell markers in diabetic corneas is significantly lower than normal, suggesting stem cell dysfunction as the basis of delayed diabetic wound healing. We have designed and successfully tested adenovirus-based combined gene therapy to alleviate these pathological changes. Current work is focused on normalizing cultured progenitor cells for future transplantation to diabetic corneas in order to translate gene therapy for corneal diabetes to clinical applications.

The Ljubimov Lab has also designed, together with viral gene therapy, a nontoxic nanopolymer for efficient gene manipulation in cultured corneal stem cells. This research is funded by an NIH R01 grant.

C-met gene therapy of organ-cultured human diabetic corneas normalizes staining of putative epithelial stem cell markers keratin 15 (K15), keratin 17 (K17) and ΔNp63∝. Limbal staining is shown. e, epithelium; s, stroma. Reproduced with permission from Mol Vis. 2011;17:2177-90.
Polymalic acid-based nanoconjugate structure and variants for gene therapy of diabetic corneal stem cells. Antisense oligonucleotides (AONs) inhibit cathepsin F (CF) and miR-409-3p that suppresses c-met expression. Polyethylene glycol copolymer (mPEG) protects against enzymatic degradation, targeting antibody to transferrin receptor (Mouse anti-human TfR mAb) ensures receptor-mediated drug endocytosis, and endosome escape unit (LLL) mediates drug release from endosomes inside the cell.

Limbal Stem Cell Deficiency

Limbal stem cell deficiency is a consequence of genetic diseases, chronic inflammation and eye burns. It results in partial to complete vision loss due to conjunctival ingrowth with neovascularization and is hard to cure even with corneal transplantation. The Ljubimov Lab has generated induced pluripotent stem cells (iPSC) from corneal epithelial cultures.

Currently, optimized protocol for their differentiation into corneal cells is being developed in collaboration with several labs in the Cedars-Sinai Regenerative Medicine Institute. This protocol would enable the creation of a bankable source of corneal epithelial cells for future transplantation to patients. This research is funded by a recent NIH R01 grant.

Cornea-derived iPSC on top of denuded organ-cultured human cornea (two weeks). They express differentiated corneal marker, keratin 3 (K3). DAPI, nuclear stain. S, stroma.

Contact the Ljubimov Lab

127 S. San Vicente Blvd.
Advanced Health Sciences Pavilion, Suite A8106
Los Angeles, CA 90048