Domesticating bacteria can help treat skin diseases

The team led by Marc Güell from the Department of Medicine and Life Sciences (MELIS) at Pompeu Fabra University has designed a kit of eleven genetic tools for Cutibacterium acnes (C. acnes) to secrete therapeutic compounds. As a proof of concept, the toolkit has been tested to make bacteria produce antioxidants in response to oxidative stress caused by ultraviolet radiation – one of the causes of skin ageing and which, in combination with other factors, can cause skin cancer. The research has been reported in the journal Cell Systems with Guillermo Nevot and Javier Santos-Moreno as first co-authors, and could be the first step towards the development of topical applications.

The toolkit contains, among other things, a plasmid. This DNA molecule contains the information that controls the secretion of the therapeutic compounds and their quantity according to external stimuli. The set also contains a control mechanism so that C. acnes does not generate its own food and thus only proliferates when it is fed externally and at the right time.

The introduction of genetically modified bacteria to treat conditions, known as engineered live biotherapeutic products (eLBPs) therapy, has already been tried in the skin. However, it has never been done with C. acnes. This is the most abundant bacteria on the skin and, although it is commonly associated with the development of acne, the presence of phylotypes II and III is a sign of healthy skin. C. acnes has been used as a live biotherapeutic product because its genome is very stable and it does not interact or recombine with other bacteria. Moreover, unlike other bacteria tested previously, it can be transplanted from donor to patient.

This study is a first step towards the development of long-lasting therapeutic creams that are safer and more affordable than other therapies. In the future, topical live biotherapeutic products could be a solution for chronic skin conditions.