Unsuspected Skin Guardian: Hemoglobin Found in Epidermis Plays a Vital Role in Protecting Skin

Unsuspected Skin Guardian: Hemoglobin Found in Epidermis Plays a Vital Role in Protecting Skin

In a groundbreaking finding, researchers have unveiled the presence of hemoglobin, a protein typically associated with red blood cells, within the epidermis, our skin’s outermost layer. This unexpected discovery, published in Elsevier’s Journal of Investigative Dermatology, sheds new light on the protective mechanisms safeguarding our skin against environmental hazards.

The study, driven by an inquisitive exploration of the epidermis’ protective functions and the unexpected substances it harbors, led to the identification of hemoglobin protein in both epidermal keratinocytes and hair follicles. This remarkable revelation adds a new dimension to our understanding of skin’s defense mechanisms.

Masayuki Amagai, MD, PhD, lead investigator of the study and a prominent figure in the fields of Dermatology and Skin Homeostasis, delves into the structural composition of the epidermis, explaining, “The epidermis is composed of keratinized stratified squamous epithelium, primarily made up of keratinocytes.”

Dr. Amagai emphasizes that previous research has highlighted the expression of various protective genes within keratinocytes during their differentiation and formation of the outer skin barrier. However, he notes that difficulties in obtaining adequate amounts of isolated terminally differentiated keratinocytes for transcriptome analysis have hindered the detection of additional barrier-related genes.

Hemoglobin, with its ability to bind gases like oxygen, carbon dioxide, and nitric oxide, also functions as an iron carrier through its heme complex. These unique properties make epidermal hemoglobin a strong candidate for antioxidant activity and potentially other roles in barrier function.

Dr. Amagai elaborates on the study’s methodology, stating, “We conducted a comparative transcriptome analysis of the whole and upper epidermis, both of which were enzymatically separated as cell sheets from human and mouse skin. Our findings revealed that the genes responsible for producing hemoglobin were highly active in the upper part of the epidermis. To confirm these results, we employed immunostaining to visualize the presence of hemoglobin a protein in keratinocytes of the upper epidermis.”

The study’s conclusions, drawn by Dr. Amagai, highlight the significance of epidermal hemoglobin in protecting keratinocytes from oxidative stress induced by both external and internal factors, including UV irradiation and impaired mitochondrial function. This protective mechanism, mediated by hemoglobin’s expression in keratinocytes, serves as an endogenous defense against skin aging and cancer.

This groundbreaking discovery opens up new avenues for research into skin’s protective mechanisms and the potential therapeutic applications of hemoglobin in addressing skin-related ailments.