The 20 gene signatures defined by this study included hair follicles, glands (sebaceous, sweat, apocrine), keratinocytes, melanocytes, endothelia, muscle, adipocytes, immune cells, and a number of pathway systems.
The resources can help us ask some important and even fun questions like,
Who is more oily- Men or Women?
Scientists compared the expression of hair follicles and sebaceous glands in men and women. Sebaceous glands are microscopic glands that are responsible for secreting the oily & waxy matter over our skin. They observed that men have more number of sebaceous glands and voilà are probably more oily than women.
Additionally, they observed a reduction in the number of sebaceous glands and hair follicles with age. This explains why our skin becomes dry and flaking as we age. Previously it was thought to be because of a decrease in keratinization and fatty metabolism with age.
As men have more sebaceous glands than women, a possible consolation for their oily skin is that they tend to age better and not wrinkle as much.
Disorders of the skin are the fourth leading cause of non‐fatal disease.
During disease, the biology and the cellular composition of the skin may change significantly and so if we knew the genes specifically expressed by cells found in the skin, we could use them to assess their change in diseases, thereby allowing us to better understand the disease and develop therapeutic interventions.
Hence scientists measured the over‐/under‐representation of various cell types in 18 skin conditions. You can go through the below figure yourself to get an idea of what is going wrong in each disease. The figure commonly called as a heat map is colored from blue to brown representing under to over-representation of cell types and structures within the human skin.
For example in group 1 which includes conditions like psoriasis (skin condition that causes red, flaky, crusty patches of skin covered with silvery scales) and squamous and basal cell carcinoma (types of skin cancer), a marked increases in the keratinocyte signature is observed, while group-2 set of skin conditions were characterised by strongly up-regulation of immune cells.
In summary, scientists have defined a set of marker genes, collectively named SkinSig for skin appendages, cell types, and pathways present in the normal human skin. This studies lay the foundation for a wide spectrum of future exploration to interrogate skin conditions and obtain novel insights into the physiological and pathological changes that occur in the skin.
Research article: Derivation of marker gene signatures from human skin and their use in the interpretation of the transcriptional changes associated with dermatological disorders, Shih et.al, The Journal of pathology.