Aquaporins are involved in the normal physiology of the skin, and the dysregulation of aquaporins is implicated in different skin disorders, serving as potential therapeutic targets.
Aquaporins (AQPs) are membrane channel proteins that allow the movement of small neutral solutes and water, playing an important role in the skin’s barrier function. The altered skin barrier system in inflammatory skin diseases is associated with altered levels of AQPs and the permeability of water and glycerol. Knowledge of the role of AQPs in the defective skin barrier and skin diseases is useful for developing potential therapeutic strategies for different skin diseases. These findings are published in the International Journal of Molecular Sciences.
Aquaporins in the Skin Barrier
AQP1 and AQP3 are present in the dermis and epidermis of the skin. AQP9 and AQP10 are present in the epidermis, whereas AQP5 is found in the eccrine sweat glands. AQP7 is primarily present in the hypodermis but also in the epidermal and dermal dendritic cells.
The Dysregulated Involvement of AQPs in Inflammatory Dermatological Diseases
Several inflammatory dermatological diseases, such as psoriasis and atopic dermatitis, are characterized by skin barrier dysfunction. AQPs play a crucial role in these conditions by regulating water transport across the skin barrier. Dysregulated expression and activity of AQPs have been observed in these diseases, contributing to impaired skin barrier function and increased water loss, leading to skin dryness and inflammation.
Inflammatory Dermatological Diseases and Skin Aquaporins
Skin cells are involved in immunological defense, preventing the penetration of microorganisms and dangerous substances. The dysregulation of the skin immune homeostasis gives rise to several inflammatory skin disorders, which include psoriasis, hidradenitis suppurativa, and atopic dermatitis.
The Link Between AQP3 and Psoriasis, AQP9 and Atopic Dermatitis
There is a decreased expression of AQP9 in atopic dermatitis, with an upregulation of AQP3. This leads to increased water loss, higher levels of inflammatory markers, and increased proliferation of keratinocytes. The downregulation of AQP3 is observed in psoriasis, which is associated with decreased activation of NK-kB, decreased hydration, and increased water loss.
Skin Barrier Impairment in Hidradenitis Suppurativa: The Role of AQP5
The downregulation of AQP5 results in the impairment of the turnover of keratinocytes and the production of sweat in hidradenitis suppurativa. This leads to a disrupted skin barrier in this inflammatory skin disease.
This review demonstrated the involvement of AQPs in different inflammatory skin conditions; therefore, potential therapeutic approaches that target AQPs may help treat these inflammatory conditions.
Tricarico, P. M., Mentino, D., De Marco, A., Del Vecchio, C., Garra, S., Cazzato, G., Foti, C., Crovella, S., & Calamita, G. (2022). Aquaporins Are One of the Critical Factors in the Disruption of the Skin Barrier in Inflammatory Skin Diseases. Int J Mol Sci, 23(7). https://doi.org/10.3390/ijms23074020