Desmond J. Tobin MRIA, Skin Scientist06 November 2023
Professor Tobin researches cutaneous science, with a focus on the regulation of skin and hair pigmentation and immune-mediated control of skin and hair growth in human health and disease.
Desmond J. Tobin MRIA, Full Professor of Dermatological Science, Charles Institute of Dermatology, School of Medicine, University College Dublin
I am fascinated with how our body’s largest organ can affect so much of how human beings function during our lifetimes.
The skin, our body’s largest organ and key social signalling system, is located at the interface of our external and internal worlds. Because of this, it is strategically placed to provide not only a barrier against a range of fluctuating noxious stressors (UV radiation, mechanical, chemical and biological insults), but also to act as the periphery’s ‘stress sensing’ system. Recent research developments suggest that skin is a key sensor that recognises, discriminates and integrates signals from myriad sources, including our immune, pigmentary and neuroendocrine systems. It is much more important in maintaining total body homeostasis than previously thought.
The last couple of decades have witnessed a new appreciation of the skin’s main appendage: the hair follicle—a (mini)organ unique to mammals. It is the only tissue that shows life-long cycling in the adult—the so-called hair growth cycle—and is an unsurpassed tool to study multiple and life-long recapitulations of developmental stages. More prosaically, and despite global economic woes, the level of monetary spend on skincare continues to astound. Our aging and increasingly diabetic populations continue to drive rising skin-fragility and wound care costs for national healthcare budgets.
My research over more than 25 years has exploited the amazing accessibility of skin and hair follicles as a multi-cellular interactome of (neuro)ectodermal (melanocytes), mesenchymal cells (fibroblasts) and epithelium (keratinocytes), and immunocytes, etc. My academic focus on skin has been informed by basic research and contexts of translating research into practice, and is strongly influenced by training in laboratories associated with clinical dermatology departments. To harness research more focused on the context of the skin with its appendages, however, I established and led the Centre for Skin Sciences in Britain (2009–18), building this centre into the second-largest academic unit of its kind there. Moreover, to bring basic skin scientists closer to organised dermatology, I served a stint as the first non-clinical chair of the British Society for Investigative Dermatology. Since my return home to Ireland in 2018, my focus has shifted to leading UCD’s Charles Institute of Dermatology as its first non-clinical director. The Charles remains the only dedicated academic centre for skin research on the island of Ireland.
My research contributions include investigation into the basis for preferential targeting of pigmented hair in the common autoimmune hair loss disease, alopecia areata, during which we found that melanocytes of the hair follicle (but not the epidermis) are targeted. Building on research from my PhD project days, my lab is interested in autoantigen discovery in alopecia areata. Affected patients have circulating antibodies to hair follicle-specific antigens, including the structural protein Trichohyalin. We now have reason to consider this protein as a source of immunodominant antigens in alopecia areata, opening potential strategies to therapeutically ‘vaccinate’ against an aberrant immune response to this protein.
We succeeded in growing adult human hair follicle melanocytes outside the body for the first time, and we used these cells to reveal striking differences in the functionality of peptides of the prohormone proopiomelanocortin in the hair follicle and epidermis. Breaking the melanocortin-centric view of human pigmentation, we showed that the opioid beta-endorphin also acts as a potent melanotropin. In Science Foundation Ireland-funded work with colleagues, we detected programmed cell death (apoptosis) in hair follicle melanocytes (this is of potential relevance in targeting apoptosis-resistant pigment cell tumor (melanoma). There are more cases of skin cancer than of all other cancers combined, with indigenous Irish skin particularly vulnerable. Together with Associate Professor Shirley Potter, I co-chair the Irish Melanoma Forum, an organisation that seeks to develop much needed basic and clinical research capacity in Ireland into melanoma.
My lab is also engaged in skin assay development (and is part of the EU Cost Action NetSkinModels), including tracking melanin transfer in the human epidermis—this would be a key evolutionary adaptation to life on a UV-irradiated planet. We observed that the atypical myosin (Myosin-X) can act as a key motor protein to drive melanin transfer between the melanocyte and keratinocyte via nanotubes called filopodia. I am currently extending this work with photobiology colleagues, to understand how optimising melanin distribution within the human skin can provide protection against UVR-associated DNA damage.
We remain very grateful to both healthy and patient donors of skin and hair follicles for our research. Despite evident patient willingness to collaborate, we can blanch at the hurdles to be crossed to access these tissues.
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