Mimicking the LOX-Related Autosomal Recessive Congenital Ichthyosis Skin Disease Using a CRISPR-Cas9 System and Unravelling 12S-LOX Function in the Skin.

Stratum Corneum (SC) formation in the human epidermis requires lipid processing. Lipoxygenases (LOXs) such as 12R-Lipoxygenase (12R-LOX) and Epidermis-type lipoxygenase 3 (eLOX-3) contribute to this process. Mutations in their genes cause Autosomal Recessive Congenital Ichthyosis (ARCI) in patients. On the other hand, 12S-lipoxygenase (12S-LOX) is expressed in the human epidermis, but its role still remains to be clarified. The involvement of eLOX-3, 12R, and 12S-LOX in conditions or processes such as skin photodamage, wound healing, psoriasis, and atopic dermatitis is suggested but still remains unclear. In order to eventually gain a better understanding of the role of these LOXs in such processes, models of Tissue-Engineered Skins (TESs) with an impaired expression for the native form of either eLOX-3, 12R-LOX, or 12S-LOX were produced using CRISPR-Cas9(D10A) technology. All three models showed impaired keratinocyte differentiation and changes in the prevalence or the size of lipid droplets within the most superficial layers, thus reproducing features observed in ARCI and supporting a role for 12S-LOX in SC formation. Since eLOX-3 and 12R-LOX depleted TES's reproduced features observed in ARCI, such models can be considered as reliable tools for the functional studies of these LOXs in the human epidermis.