Skin condition seborrheic dermatitis
New therapeutic approach and breakthrough in understanding sebaceous glands

Ulm University

The skin is the largest organ of the human body and determines our external appearance: Therefore, diseases such as seborrheic dermatitis can significantly reduce the quality of life for those affected. This skin condition is characterised by a mostly scaly rash on the face and scalp. Some patients - often infants and middle-aged people - also suffer from itching. The pathological process of the condition is not yet fully understood. It is assumed that various causes interact, such as inflammatory reactions to yeast fungi and a genetic predisposition.

Researchers led by Professor Karin Scharffetter-Kochanek, Medical Director of the Ulm University Clinic for Dermatology and Allergology, and her research assistant Dr. Karmveer Singh are now bringing the transcription factor JunB into play. In the renowned journal Nature Communications, the group from Ulm, Cologne, Heidelberg and Rome describes a previously unknown function of the transcription factor that can lead to new therapeutic approaches in seborrheic dermatitis.

In the skin, transcription factor JunB plays an important role: it ensures the differentiation of the epidermal stem cells - also known as the formation of new skin cells. JunB thus keeps the skin in balance. In the mouse model and with the help of methods such as Next Generation Sequencing, the authors have now been able to show: A missing transcription factor leads to structural and functional limitations of the sebaceous glands and, in consequence, a disrupted lipid layer of the skin. Genetically modified mice without JunB develop enlarged sebaceous glands and eventually a disease similar to seborrheic dermatitis in humans. 'However, a subtype of skin stem cells that lack JunB begins to form new sebaceous glands during wound healing,' explains Scharffetter-Kochanek. This process, which is described in the publication, is called fate switch, or plasticity of cell differentiation. These new findings highlight the important role of JunB in skin regeneration and possibly in the development of seborrheic dermatitis.

In any case, the research results are highly relevant for the future treatment of the skin disease: 'A better understanding of the function of the transcription factor JunB may lead to new therapeutic approaches for patients suffering from sebaceous gland dysfunction,' said Dr. Karmveer Singh. Overall, the findings also contribute to a better understanding of the sebaceous glands of the skin and hair.

The work of the group at the University Medical Centre Ulm, the German Cancer Research Center (DKFZ) as well as the University of Cologne and the University of Rome received funding from the German Research Foundation (DFG) (KFO 142, SFB 1149, GRK 1789) and through the 'Cellular Decision and Signalling Pathways in Ageing' funding line of the Baden-Württemberg Ministry of Science, Research and the Arts (MWK).

Literature reference:
Singh K., Camera E., Krug L., Basu A., Pandey R., Munir S., Wlaschek M., Kochanek S., Schorpp-Kistner M., Picardo M., Angel P., Niemann C., Maity P., Scharffetter-Kochanek K. (2018) JunB defines functional and structural integrity of the epidermo-pilosebaceous unit in the skin. Nature Communications 9, Article number 3425, DOI: 10.1038/s41467-018-05726-z

Microscopic image of a tissue section of a mouse with deactivated transcription factor JunB. The symptoms correspond to seborrheic dermatitis. This chronic form of skin eczema leads to the formation of a scaly rash on skin surfaces with many sebaceous glands. The microscopic image clearly shows the inflammatory thickenings in the epidermis and the sebaceous glands as well as the penetration of inflammatory cells into the skin tissue. (image: Dr. Karmveer Singh / University Medical Centre Ulm)
Dr. Karmveer Singh is a research assistant at the University Clinic for Dermatology and Allergology in Ulm. (photo: University Medical Centre Ulm)