EB Biobank at UCD's Charles Institute

Biobanks are collections of biological samples (such as cells, DNA, blood or tissue) and their associated data (such as mutation type) that are used to support the discovery of new scientific and medical knowledge. As we are all different genetically, personalised medicine aims to make treatments that work very specifically for individual patients. Biobanks are one of the essential tools in helping to develop and evaluate new approaches to personalised medicine.

The Wang Lab’s scientists have established an epidermolysis bullosa (EB) biobank at University College Dublin (UCD) in collaboration with Children’s Health Ireland at Crumlin Hospital and Consultant Dermatologist, Dr Fiona Browne. Our EB biobank, named the UCD/CHI EB Skin Biobank, is composed of skin cells (keratinocytes and fibroblasts) isolated from skin biopsies from EB patients and healthy donors. After the skin cells are isolated, they are stored at a very low temperature to be used exclusively for EB research. We will use the cells as an evaluation tool to know if our treatments are going in the right direction and have potential to be translated into the clinic in the future, so the new data generated will be information about the treatments we are evaluating, not about the cells themselves.

Cells are continuously renewed in our skin, however as we age the skin renewal process slows down and skin cells become less efficient at dividing and producing new cells. Our biobank is composed from cells obtained from skin biopsies of children, as this means researchers can use them for longer and fewer participants need to donate their skin samples.

Our EB biobank has been approved by the Children’s Health Ireland Research Ethics Committee (CHI REC REF: REC-007-21) and UCD’s Ethics Committee (UCD REC REF: LS-E-22-27-Wang) and will be used to investigate:

• All subtypes of EB, although currently our research is mainly focused on recessive dystrophic EB (RDEB). However, the strategies under development for RDEB could be adapted to other EB subtypes.

• Different mutations for EB (including for RDEB) as we are developing different therapeutic strategies in our research projects and some of them are dependent on specific mutations.

All of our new research projects that involve the use of the EB biobank are reviewed by the Children’s Health Ireland Research Ethics Committee and UCD’s REC – LS-X-X-X-Wang before we start. This webpage will be updated regularly as new projects are approved and started.

EB is a skin blistering condition in which patients are born with EB, it is a genetic disease. EB makes skin so fragile that it can blister at the slightest touch. Currently there is no treatment or cure. There are few people in the world who suffer from EB, so it is considered a rare disease - an estimated 1 in 18,000 babies born in Ireland are affected by EB. Over 500,000 people have EB worldwide. The skin becomes fragile because one of several proteins that act as a “velcro” between the different layers of our skin cannot be formed correctly, so the “velcro” does not work properly and the slightest touch causes a blister (see video in link 1 for explaining how this happens). The information for producing all the proteins of our body is kept in our cells in the form of genes. When the information in our genes is wrong (scientists call this mistake a mutation), a specific protein cannot be produced, and this can cause a disease. In the case of EB, different subtypes exist depending on which skin protein, involved in forming the “velcro”, is missing. The information to produce each of those skin proteins is contained in different genes inside of the cells, thus different EB subtypes are related to specific genes. As an example, in the case of dystrophic EB (DEB) the “velcro” is composed by anchoring fibrils formed by the collagen VII protein. Collagen VII protein is produced by the COL7A1 gene. In DEB, COL7A1 gene is mutated, so collagen VII is not produced so no anchoring fibrils to keep the skin together are missed and blisters produced with the slightest touch.

In our projects, we develop potential treatments for EB based on gene therapy, treatments that try to solve the problem caused by the mutated genes (see video about gene therapy in link 2 for better understanding). In gene therapy, we need to bring into the cells the genetic information that cells are missing, for example the correct information for producing collagen VII in dystrophic EB (DEB), contained in the COL7A1 gene. Viruses are often used for this, but they have some disadvantages, so instead of using viruses, we use synthetic polymers. Examples of synthetic polymers include nylon, polyethylene and polyester, usually used for your clothes, but our polymers are so tiny that you cannot see them. Our polymers have been designed for application directly onto the EB patients’ skin in future and would bring into their skin cells the information they need to correctly produce the missing protein, helping their skin to heal the wounds and prevent the formation of new ones. We have two different types of treatments for RDEB under development:

• GENE REPLACEMENT: In this approach, we use special chemicals to put genetic instructions back in cells so they then make the healthy protein they are missing. The drawback of gene replacement treatments is that their effect will last for a limited time, until the healthy protein is degraded inside of the body (1.5 to 2 months for collagen VII protein). Then the gene replacement strategy would need to be applied again, being a chronic treatment. The benefit of the gene replacement treatments is that the same treatment can be applied to all patients with the same gene affected, for example all patients with RDEB (as all of them have mutations in the same gene, called the COL7A1 gene).

Our gene replacement projects:

• GENE EDITING: In this approach, researchers design a ‘smart scissors’ which can be used to make changes to genes that are broken. This technique is call CRISPR and our research hopes to use it to fix mutations that cause EB. There are some mutations causing EB that after they are removed, the cell is then able to produce the missing skin protein; this new protein will be a bit smaller but fully functional. Other mutations require the insertion of the healthy version of the excised part of the gene to be able to restore protein production (see video in link 3 for better understanding of gene editing). The advantage of the gene editing treatments is that the changes (edits) made in the cells will permanently correct the wrong genetic information. Every time a corrected cell divides, it produces two new cells that will have the corrected information as well. In our skin there are some epidermal stem cells, a type of cell that never dies and constantly produces new skin cells. The target of gene editing treatments is to correct epidermal stem cells, as this ensures that new cells made in the skin will be corrected and healthy. The drawback of the gene editing treatments is that each treatment can only be applied to patients that have the same mutation in the same gene, so only patients with the same wrong information to produce the skin protein can be treated with each gene editing treatment developed - thus it is a personalised medicine. For example, RDEB patients with mutations in a region of the COL7A1 gene called exon 80 would need a gene editing treatment with specific coordinates (sgRNA), but RDEB patients with mutations in a different region of COL7A1 gene will need different coordinates (sgRNA), thus a different gene editing medicine. Although fewer patients can be treated with this option, they will need to be treated less times as in each treatment more cells will be corrected, due to a cumulative effect.

Our gene editing projects:

Non-viral Cas12a gene editing approach for DEB” Principal Investigator: Prof Wenxin Wang and Co-investigators: Dr Fiona Browne, Dr Irene Lara-Sáez; funded by DEBRA Ireland for 2 years with the aim of developing a safer gene editing treatment to correct the most common mutations causing dystrophic EB (DEB) in Ireland by using CRISPR/Cas12a, a very novel genetic tool and safer than Cas9.

Useful links:

1. Understanding EB: https://www.youtube.com/watch?v=WjXV3h5wUfc&list=PLQcqi5nu7CuKZj4nHIymFhYoep6-8A_oz
2. Basics for gene therapy: https://www.youtube.com/watch?v=BxEoX6TkitY
3. Basics for gene editing: https://www.youtube.com/watch?v=XPDb8tqgfjY

For more information about EB, please visit the EB Research Partnership website (https://www.ebresearch.org/what-is-eb.html) and DEBRA Ireland’s website (https://debraireland.org/about/what-is-eb/).