Curiosity about what surprising molecules are expressed in the epidermis and how the epidermis shields our sensitive body from the environment drove this research. Hemoglobin? was found by researchers in hair follicles and keratinocytes of the epidermis. This surprising data expands on our knowledge of how our skin’s defense mechanisms function.
For the first time, studies have demonstrated that hemoglobin, a protein that binds oxygen in red blood cells, is also present in the epidermis, the outermost layer of our skin. The study offers significant new information about the characteristics of our skin’s outermost layer of protection and is published in the Elsevier Journal of Investigative Dermatology.
“Keratinized stratified squamous epithelium, which is primarily composed of keratinocytes, makes up the epidermis,” says Masayuki Amagai, MD, PhD, lead investigator of the study, Department of Dermatology, Keio University School of Medicine, Tokyo, and Laboratory for Skin Homeostasis, RIKEN Center for Integrative Medical Sciences, Yokohama. Previous research has shown that during keratinocyte differentiation and the formation of the outer skin barrier, a variety of genes with protective functions are expressed. However, because it was difficult to obtain sufficient numbers of isolated terminally differentiated keratinocytes for transcriptome analysis, other barrier-related genes went undetected until later.”
Hemoglobin is an iron carrier through the heme complex and binds gases like oxygen, carbon dioxide, and nitric oxide. Because of these characteristics, epidermal hemoglobin is a strong contender for roles in barrier function and antioxidant activity.
Professor Amagai goes on, “We performed a comparative transcriptome analysis of the upper and whole epidermis, which were isolated as cell sheets from human and mouse skin using an enzyme separation technique. We found that the upper layer of the epidermis contained highly active hemoglobin-producing genes. We employed immunostaining to visualize hemoglobin? protein in keratinocytes of the upper epidermis in order to validate our findings.”
Professor Amagai ends by saying, “Our research demonstrated that oxidative stress increased the expression of epidermal hemoglobin and decreased the generation of reactive oxygen species in human keratinocyte cell cultures. According to our research, haemoglobin shields keratinocytes from internal and external sources of oxidative stress, such as UV radiation and malfunctioning mitochondria, respectively. Thus, keratinocytes’ production of hemoglobin serves as an innate defense mechanism against skin aging and skin cancer.”