Keloid scarring is a dermal fibroproliferative response characterized by excessive and progressive deposition of collagen; aetiology and molecular pathology underlying keloid formation and progression remain unclear. Genetic predisposition is important in the pathogenic processes of keloid formation, however, environmental factors and epigenetic mechanisms may also play pivotal roles. Epigenetic modification is a recent area of investigation in understanding the molecular pathogenesis of keloid scarring and there is increasing evidence that epigenetic changes may play a role in induction and persistent activation of fibroblasts in keloid scars. Here we have reviewed three epigenetic mechanisms: DNA methylation, histone modification and the role of non-coding RNAs. We also review the evidence that these mechanisms may play a role in keloid formation - in future, it may be possible that epigenetic markers may be used instead of prognostic or diagnostic markers here. However, there is a significant amount of work required to increase our current understanding of the role of epigenetic modification in keloid disease.

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Fibrosis is a common pathological state characterized by the excessive accumulation of extracellular matrix components, but the pathogenesis of the disease is still not clear. Previous studies have shown that microRNA-29 (miR-29) can play pivotal roles in the regulation of a variety of organ fibrosis, including cardiac fibrosis, hepatic fibrosis, lung fibrosis, systemic sclerosis, and keloid. In this review, we outline the structure, expression, and regulation of miR-29 as well as its role in fibrotic diseases.

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Keloid scarring is a fibroproliferative disorder of the skin of unknown pathophysiology, characterised by fibrotic tissue that extends beyond the boundaries of the original wound. 1 Keloids develop as a result of disturbance to skin architecture by any wound, and have a strong genetic component, appearing in ethnicities with darker skin pigmentation. 1 There are estimated to be over 11 million keloids in the developed world, with the global number unknown but expected to be higher. 2 Current dogma suggests keloid development follows a similar pathway to normal wound healing but with chronic progression, suggesting disturbance in the fine control of cellular functions that occur during wound healing. 3 Epigenetics, defined as non-base-pair sequence alterations to the DNA, is a key regulator of cell functions, and aberrant epigenetic modifications have been found to contribute to many pathologies, including keloid scars. Our knowledge of progressive fibrosis remains limited, and therapeutic options are few and commonly ineffective, with keloids commonly recurring even after surgery and adjunct treatments. There is an urgent need to gain critical knowledge that will allow us to design better therapeutic strategies and provide evidence to support clinical decisions. This review will explore the current knowledge of the contribution of epigenetic modifications such as DNA methylation, histone modification, microRNAs, long non-coding RNAs to keloid scar formation and progression, and potential treatments utilising modifiers of these processes.

Melanoma is a common skin cancer associated with ultraviolet light exposure and genetic variance. However, the etiology and molecular mechanisms of melanoma remain unknown. Recent studies have shown that microRNAs (miRNAs) can play key roles in the development and prognosis of this disease. In this study, we reviewed several pivotal miRNAs that may contribute to melanoma by involvement in the processes of invasion, migration, and metastasis of melanoma cells.

Scarring is a lifelong consequence of skin injury, with scar stiffness and poor appearance presenting physical and psychological barriers to a return to normal life. Lysyl oxidases are a family of enzymes that play a critical role in scar formation and maintenance. Lysyl oxidases stabilize the main component of scar tissue, collagen, and drive scar stiffness and appearance. Here we describe the development and characterisation of an irreversible lysyl oxidase inhibitor, PXS-6302. PXS-6302 is ideally suited for skin treatment, readily penetrating the skin when applied as a cream and abolishing lysyl oxidase activity. In murine models of injury and fibrosis, topical application reduces collagen deposition and cross-linking. Topical application of PXS-6302 after injury also significantly improves scar appearance without reducing tissue strength in porcine injury models. PXS-6302 therefore represents a promising therapeutic to ameliorate scar formation, with potentially broader applications in other fibrotic diseases.

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