Exopharm (ASX: EX1) has produced prototype exosome (extracellular vesicle [EV]) products containing Elastin Messenger Ribonucleic Acid (ELN-mRNA-EV) using a number of its proprietary manufacturing technologies.
The company has been working on an in-house exosome prototype product to increase elastin – as a potential additive gene-therapy product to treat elastin deficiency in skin, arteries, lungs and other tissue.
Elastin (ELN) is a large natural molecule found in the extracellular matrix surrounding cells – elastin imparts elasticity to the tissue. ELN normally has a long half-life of approximately 70 years and its natural replacement is limited in adults. Elastin constitutes about 28%–32% of major blood vessels, 30%–57% of the aorta, 50% of elastic ligaments, 3%–7% of lung, and 2%–3% of the dry weight of skin.
With aging, injuries, exposure to UV light (from sun exposure) and many other environmental factors, such as smoke, the normal levels of elastin decrease and medical and aesthetic issues arise from that elastic deficiency.
Exopharm selected an additive gene-therapy for elastin deficiency as a development target as elastin deficiency is not readily treated by dietary or other means and Exopharm’s exosomes could be a useful drug-delivery chassis for ELN mRNA.
Medical problems that could potentially be treated with an additive gene-therapy for elastin include photoaging, striae distensae alba (stretch marks), aging skin, photoaged skin, arterial stiffness, chronic obstructive pulmonary disease (COPD) and Williams-Beuren syndrome amongst others.
Prototype exosome product to increase elastin production by human cells
The work was designed to compare ‘naked’ (i.e. no drug-delivery technology used) ELN mRNA with exosome-delivered ELN mRNA as a way of increasing human cell production of elastin.
Making the prototype ELN-mRNA-EV product involved a number of steps:
1. Culture human HEK293 cells in Exopharm’s proprietary collection media Hexocollect
2. Purify exosomes from cells using Exopharm’s patented LEAP technology
3. Use Exopharm’s LOAD technology to add mRNA into exosomes
4. Conduct analytics to determine copy-number of mRNA LOADing
Exopharm’s suite of proprietary manufacturing technologies has enabled this work.
ELN-mRNA-EVs and other test materials were delivered to human fibroblasts in vitro to form 4 test materials.
Two days following treatment with various test materials, cells were collected and assessed for ELN content.
ELN-mRNA-EVs were compared to a PBS (Phosphate Buffered Saline) vehicle control, an unloaded HEK293 (naïve) EV control and an equivalent amount of loading reagent and ELN mRNA (equivalent to LOADed test material) control.
Findings and results
At the end of treatment, cells administered ELN-mRNA-EVs showed a clear difference in cell morphology (i.e. how the cells appear) compared to control and other test panels.
Following cell harvest, analysis showed ELN gene expression was elevated 4-fold in ELN-mRNA-EVs treated cells compared to controls (normalised to native ELN), and around 4-fold increase over ‘naked’ ELN mRNA materials.
Elevated gene expression translated to more than two-fold increase in ELN protein content compared to controls as determined by FASTIN assay.
This data shows ability to load mRNA into EVs and that the ELN mRNA is subsequently processed within the cells into ELN protein.
ELN is not typically produced by mature cells, so using ELN-mRNA-EVs to induce ELN protein expression is a step towards potential clinical utility of exosomes as a drug-delivery chassis for additive gene therapy for elastin-deficiency.
Limitations and next steps
This study is an in vitro study with limited replicates. The next step would be to test the ELN- mRNA-EVs in ex vivo human skin experiments. Previous testing has demonstrated HEK293 naïve exosomes to be nontoxic and non-immunogenic in animal studies. A further potential step could be to conduct an animal study or a small human study.