Alopecia areata (AA) is an autoimmune form of hair loss involving infiltration of CD8+ T cells in the hair follicles (HFs) in conjunction with the upregulated antigen presentation processes. The growing (anagen) HFs are preferentially attacked in AA, leading to the hypothesis that epitopes derived from anagen-specific proteins are targeted by the T cells. Melanogenesis is a highly active process during anagen and clinical observations reported preferential loss of pigmented hairs during the initial onset of AA and regrowth of unpigmented hair during recovery. However, whether melanogenesis antigens are an inciting factor for AA has not been determined. We utilized a computer-assisted epitope prediction algorithm to design a panel of candidate CD8 T cell-specific epitope sequences in the C3H/HeJ mouse model, which we derived from several sources including our previous GWAS studies, published data, and known melanogenesis proteins. In addition, we isolated protein homogenates from the skin of AA-affected and normal-haired C3H/HeJ mice at either anagen or telogen stages of hair cycle. The epitope peptides and protein homogenates were used to stimulate skin-draining lymph node cells (LNCs) of C3H/HeJ mice with chronic AA or normal-haired mice and assessed the number of activated IFNg-producing CD8 T cells via ELISpot assays. We found that anagen stage protein homogenates induced a higher level of CD8 T cell activation, especially those with higher molecular weight, supporting the hypothesis that AA is an anagen-specific disease. Interestingly, epitopes derived from melanosomal membrane glycoprotein OA1 and transport protein SLC24A5 and SLC45A2 induced significantly higher frequency of CD8 T cell activation. Some of the antigens that showed higher antigenicity were suggested in previous studies to display molecular mimicry with peptides from the HBV vaccine. Further finemapping of epitopes will help define AA-associated antigens and the development of potential antigen-specific tolerogenic therapies. DNA immunization has theoretical and practical advantages over conventional protein-based immunization strategies. Though studies in animal models demonstrate the promise of nonviral DNA vaccines, clinical translation has thus far been disappointing. Here we develop a unique approach to increase the immunogenicity of non-viral DNA vaccines by combining "skin targeting" with a novel keratinocyte targeted approach to create a pro-immunogenic cutaneous microenvironment. Specifically, we co-delivered antigen with the transcription factor x-box binding protein 1 (XBP1) to the skin. XBP1 is an endoplasmic reticulum (ER) stress-associated factor that regulates ER function, promotes the production and secretion of proteins, regulates survival and function of antigen presenting cells, and has been shown to induce innate immunity under some conditions. In mouse models, we find that compared to delivery of antigen encoding plasmid alone, co-delivery with K14 promoter driven XBP1 plasmid DNA results in improved antigen-specific humor...

Polycomb repressive complexes (PRCs) are essential chromatin regulators of cell identity. PRC1, which is a dominant executer of Polycomb-mediated control, possesses catalyticdependent H2AK119 mono-ubiquitination and catalytic-independent activities. Despite extensive knowledge of PRC1s role in embryonic stem cells (SCs), its function in somatic SCs and tissue development is largely unknown. Here, we show that despite its well-established repressor functions, PRC1 binds to both silent and active genes in epidermal progenitors. Through loss-of-function studies, we show that global PRC1 function is essential for skin development and SC specification, whereas PRC1 catalytic activity is dispensable. By dissecting molecular mechanisms, we show that PRC1 catalytic-dependent and -independent activities repress non-skin lineage genes and attenuate expression of differentiation and proliferation genes. Interestingly, PRC1 also binds to and promotes the expression of critical skin developmental and SC genes independently of its catalytic activities. Our findings highlight PRC1s diverse roles in executing a precise developmental program. 1359

United StatesMelanoDermÔ, supplied by MatTek Corporation, Ashland, MA is a commonly used in vitro model to test a formula or ingredient's impact on melanin and therefore their ability to even or lighten skin tone. MelanoDermÔ is a 3D constructed, live, manufactured skin culture that is widely used as a screening tool in the cosmetic industry to study melanogenesis and pigmentation. In this study, we evaluated well-known cosmetic compounds i.e. hydroquinone and kojic acid causing effects on melanin and melanogenesis in vivo, as relevant benchmark positive controls for in vitro screening architecture of other actives alone or in combination. Hydroquinone was tested in water solution as a single ingredient or as finished goods formulation at the concentration of 2% and Kojic Acid was investigated in water solutions at two different concentrations (1% and 2%) for their ability to reduce existing and new pigment formation on MelanoDermÔ (MEB-300B) tissues after 14 days of topical application. Cell viability was assessed with MTT assay, color measurements (L*, a*, b* values) with chromameter, and in situ histology of the selected tissues was performed with Hematoxylin and Eosin staining. Hydroquinone evaluation in this model was somewhat challenging due to its known cytotoxicity geared specifically towards melanocytes, while kojic acid was safe at the concentration of 1%. Generated data indicate that both actives may be used as positive controls and thus serve as a validated model in screening architecture of the new perspective skin lightening/brightening actives and represent a translation platform between vitro-to-vivo studies. It is well known that the cosmetic property of evening skin tone can help reduce the visible signs of aging on photodamaged skin. Photodamage originates from a variety of environmental aggressors including UV exposure, high energy visible light, and pollutants. Mel-anoDermÔ is a commonly used in vitro method to test a formula or ingredient's impact on melanin and therefore ability to even skin tone. MelanoDermÔ, supplied by MatTek Corporation, Ashland, MA, is a 3D constructed, live, synthetic skin culture that is widely used in the cosmetic industry. L-ascorbic acid is a known reactive oxygen species (ROS) scavenger and is often claimed to even skin tone through several biological pathways, including its ability to interrupt melanin synthesis by interacting with the copper ions at the active site of the enzyme Tyrosinase, a key enzyme in melanogenesis (pheomelanin and eumelanin); an increase in the amount and location of melanin in the skin is responsible for areas of uneven skin tone, and thus the appearance of aged skin upon exposure to environmental aggressors. This study was designed to test several topical dermatologics containing different levels of Lascorbic acid, and its esters, along with other ingredients in their ability reduce melanin pigment and its further formation on MelanoDermÔ (MEL-300B) tissues after 14 days of topical application. The CIE L*a*b* values were recorded with S...

Other health maintenance practices were generally associated with both SCC and BCC. Our results demonstrate potential detection bias in epidemiologic studies of skin cancer, which future studies should take into consideration.

Becker's nevus is a common cutaneous disorder with unknown pathogenesis, affecting between 1 in 200 to 1 in 50 individuals. Affected individuals typically develop a hyperpigmented overgrowth of hair and tissue on their torso or upper extremities during adolescence which can be distressing. In some cases, Becker's nevi can be associated with underlying ipsilateral muscle hypoplasia or other extracutaneous abnormalities, termed Becker's nevus syndrome. Whole-exome, Sanger, and CRISPR site-specific sequencing identified recurrent hotspot mutations in the cytoplasmic beta-actin encoding gene ACTB (p.R147C, p.R147S) in 14/24, or 58% of Becker's nevi that was absent from adjacent non-lesional skin tissue. Interestingly, the ACTB mutation was also detected in an individual with Becker's nevus syndrome with unilateral delayed breast development. Laser capture microdissection of Becker's nevi revealed the mutation occurred solely in the smooth muscle bundles of the skin. Functional analysis of the ACTB mutations in myocytes showed that this mutation did not affect F-actin stability, nor increased signaling activity of the RAS or Hedgehog signaling pathways as measured by phospo-Erk and Gli1 respectively. Further investigation into the novel role of postzygotic ACTB mutations in Becker's nevi is recommended.