The findings demonstrate that embigin binds to the extracellular matrix protein called fibronectin that acts as adhesion molecule for cells.

A fluorescence microscopy image of adult mouse sebaceous glands expressing embigin (violet/red/yellow spectrum). Cell nuclei are blue and the long tubular structures are hair follicles.

Stem cells and progenitor cells play an important role in the renewal of multiple tissues. Dr Kalle Sipilä, based in Professor Fiona Watt´s research group in the Centre for Gene Therapy & Regenerative Medicine, has discovered a molecule called embigin on the surface of epithelia progenitor cells and proven its significance to sebaceous gland function.

"Embigin was discovered in malignant embryonic cells decades ago. However, little has been known about how this molecule functions and what kind of role it has in the normal cells of the body”

– Dr Kalle Sipilä, first author

Researchers found that purified embigin protein bound tightly to fibronectin, one of the molecules that are abundantly found in the space between cells to support cell adhesion. Interestingly, embigin seems to operate in the body in the same way as in a laboratory: when researchers at King’s removed embigin from the stem cells of the skin by editing the mouse genome they found that the sebaceous gland progenitor cells detached from the extracellular matrix and began their differentiation prematurely.

"Embigin does not only help cells to adhere and differentiate punctually, but it also directs some transport proteins on the cell surface, through which precursors molecules of lipid synthesis can access the cell. This process is especially important for the sebum production to lubricate skin.”

– Dr Kalle Sipilä, first author

The interaction of stem cells with their niche extracellular matrix is important for nearly all stem cell types of the body. The European Medicines Agency approved the first stem cell therapy in 2015 for the treatment of damaged cornea, and the applications of different stem cells in the repairing of tissues are under intensive investigation currently. According to Sipilä, one of the great challenges of stem cell research is to create an artificial laboratory environment, in which the cells can adhere supporting cell renewal and differentiation as in a normal tissue.

The work was done in close collaboration with Professor Jyrki Heino’s research group from the University of Turku, Finland, which highlights the importance of multinational collaborations, researcher mobility, and interdisciplinary collaborations for biomedical research.

Read the full article Embigin is a fibronectin receptor that affects sebaceous gland differentiation and metabolism in Developmental Cell.