Unexpected Expression of Hemoglobin Alpha as an Endogenous Antioxidant in Epidermal Keratinocytes

The study discovered that hemoglobin α (HBA), typically known for its role as an oxygen transporter in erythroid cells, is expressed in epidermal keratinocytes, particularly in the upper layers of the skin and the bulge region of hair follicles. This expression was found to be more prominent after exposure to ultraviolet (UV) radiation, a major cause of oxidative stress in the skin. The researchers concluded that HBA acts as an endogenous antioxidant in these cells, protecting them from oxidative stress and potentially preventing skin cancers. Interestingly, HBA expression was not observed in other stratified squamous epithelia like the tongue, esophagus, forestomach, and vagina in mice. This suggests that HBA's antioxidant role may be specific to sun-exposed epithelium and hair follicle stem cells.