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Pigment Cell & Melanoma Research Mar 2024The human red hair color (RHC) trait is caused by increased pheomelanin (red-yellow) and reduced eumelanin (black-brown) pigment in skin and hair due to diminished...
The human red hair color (RHC) trait is caused by increased pheomelanin (red-yellow) and reduced eumelanin (black-brown) pigment in skin and hair due to diminished melanocortin 1 receptor (MC1R) function. In addition, individuals harboring the RHC trait are predisposed to melanoma development. While MC1R variants have been established as causative of RHC and are a well-defined risk factor for melanoma, it remains unclear mechanistically why decreased MC1R signaling alters pigmentation and increases melanoma susceptibility. Here, we use single-cell RNA sequencing (scRNA-seq) of melanocytes isolated from RHC mouse models to define a MC1R-inhibited Gene Signature (MiGS) comprising a large set of previously unidentified genes which may be implicated in melanogenesis and oncogenic transformation. We show that one of the candidate MiGS genes, TBX3, a well-known anti-senescence transcription factor implicated in melanoma progression, binds both E-box and T-box elements to regulate genes associated with melanogenesis and senescence bypass. Our results provide key insights into further mechanisms by which melanocytes with reduced MC1R signaling may regulate pigmentation and offer new candidates of study toward understanding how individuals with the RHC phenotype are predisposed to melanoma.
Topics: Mice; Animals; Humans; Melanoma; Receptor, Melanocortin, Type 1; Melanocytes; Pigmentation; Gene Expression Regulation; Hair Color
PubMed: 37972124
DOI: 10.1111/pcmr.13141 -
Animal Genetics Feb 2022Our understanding of canine coat colour genetics and the associated health implications is developing rapidly. To date, there are 15 genes with known roles in canine... (Review)
Review
Our understanding of canine coat colour genetics and the associated health implications is developing rapidly. To date, there are 15 genes with known roles in canine coat colour phenotypes. Many coat phenotypes result from complex and/or epistatic genetic interactions among variants within and between loci, some of which remain unidentified. Some genes involved in canine pigmentation have been linked to aural, visual and neurological impairments. Consequently, coat pigmentation in the domestic dog retains considerable ethical and economic interest. In this paper we discuss coat colour phenotypes in the domestic dog, the genes and variants responsible for these phenotypes and any proven coat colour-associated health effects.
Topics: Animals; Dog Diseases; Dogs; Hair Color; Phenotype; Pigmentation; Pigmentation Disorders
PubMed: 34751460
DOI: 10.1111/age.13154 -
NTM Dec 2021
Topics: Ferrocyanides; Pigmentation
PubMed: 34491368
DOI: 10.1007/s00048-021-00311-w -
Infection Dec 2021Cydnidae bug (also termed the burrowing bug) are arthropods of the order Hemiptera, that are recognized by their morphological adaptations for digging. They release an...
Cydnidae bug (also termed the burrowing bug) are arthropods of the order Hemiptera, that are recognized by their morphological adaptations for digging. They release an odorous substance from special glands that serve as self-defense, causing pigmented macules when in contact with human skin, especially during the rainy season. Knowledge of this rarely described condition can help avoid unnecessary investigation(s).
Topics: Animals; Heteroptera; Humans; Pigmentation
PubMed: 32654020
DOI: 10.1007/s15010-020-01481-w -
ELife Jun 2021Analysing changes in hair pigmentation may lead to a better understanding of the impacts of 'life events' on human biology and aging.
Analysing changes in hair pigmentation may lead to a better understanding of the impacts of 'life events' on human biology and aging.
Topics: Aging; Hair; Hair Color; Humans; Pigmentation
PubMed: 34190044
DOI: 10.7554/eLife.70584 -
Anais Brasileiros de Dermatologia 2024The vast majority of publications in dermatology refer to lightly pigmented skin, with few addressing the peculiarities of black skin. In addition there is no consensus... (Review)
Review
The vast majority of publications in dermatology refer to lightly pigmented skin, with few addressing the peculiarities of black skin. In addition there is no consensus on what it means to be black in different regions of the world. The lack of knowledge on the subject makes it difficult to recognize and manage dermatoses in this type of skin. This article aims to review the literature on intrinsic characteristics, as well as epidemiological and clinical aspects of the cutaneous manifestations of different dermatoses in black skin. It was found that there are sometimes striking differences, in the structural, biological, and functional aspects when comparing lightly pigmented and black skin. There are also physiological changes that need to be recognized to avoid unnecessary interventions. Some dermatoses have a higher incidence in black skin, such as acne, eczema, dyschromia and dermatophytosis. On the other hand, several dermatoses are more specific to black skin, such as pseudofolliculitis barbae, keloid, dermatosis papulosa nigra, ulcers caused by sickle-cell anemia, dactylolysis spontanea, confluent and reticulated papillomatosis of Gougerot and Carteaud, and some diseases of the hair and scalp (including fragile and brittle hair, traction alopecia, folliculitis keloidalis nuchae, folliculitis dissecans and central centrifugal cicatricial alopecia). A spectrum of peculiar aspects of specific dermatoses, including sarcoidosis, lichen planus (with emphasis on the pigmentosus variant), psoriasis, lupus erythematosus, vitiligo, syphilis, pityriasis versicolor, and neoplasms are highlighted. In the latter, characteristics of basal cell carcinoma, squamous cell carcinoma, and melanoma are compared, in addition to highlighting unusual aspects of primary cutaneous T-cell lymphoma, endemic Kaposi sarcoma, and dermatofibrosarcoma protuberans.
Topics: Humans; Skin Diseases; Skin Pigmentation; Skin; Black People
PubMed: 38310012
DOI: 10.1016/j.abd.2023.10.001 -
Trends in Ecology & Evolution May 2021Melanins are widespread pigments in vertebrates, with important roles in visual signaling, UV protection, and homeostasis. Fossil evidence of melanin and melanin-bearing... (Review)
Review
Melanins are widespread pigments in vertebrates, with important roles in visual signaling, UV protection, and homeostasis. Fossil evidence of melanin and melanin-bearing organelles - melanosomes - in ancient vertebrates may illuminate the evolution of melanin and its functions, but macroevolutionary trends are poorly resolved. Here, we integrate fossil data with current understanding of melanin function, biochemistry, and genetics. Mapping key genes onto phenotypic attributes of fossil vertebrates identifies potential genomic controls on melanin evolution. Taxonomic trends in the anatomical location, geometry, and chemistry of vertebrate melanosomes are linked to the evolution of endothermy. These shifts in melanin biology suggest fundamental links between melanization and vertebrate ecology. Tissue-specific and taxonomic trends in melanin chemistry support evidence for evolutionary tradeoffs between function and cytotoxicity.
Topics: Animals; Fossils; Melanins; Melanosomes; Pigmentation; Vertebrates
PubMed: 33549373
DOI: 10.1016/j.tree.2020.12.012 -
Pediatric Dermatology Nov 2022After the skin is irritated or injured, the color of the skin can change. The skin may become darker or lighter than the natural skin color. This skin color change is...
After the skin is irritated or injured, the color of the skin can change. The skin may become darker or lighter than the natural skin color. This skin color change is called postinflammatory pigment alteration. The color change is temporary but can be worrisome for families.
Topics: Humans; Pigmentation Disorders; Skin Pigmentation; Skin
PubMed: 36440999
DOI: 10.1111/pde.15203 -
EMBO Reports Jul 2023Dysregulation of the activity of the mechanistic target of rapamycin complex 1 (mTORC1) is commonly linked to aging, cancer, and genetic disorders such as tuberous...
Dysregulation of the activity of the mechanistic target of rapamycin complex 1 (mTORC1) is commonly linked to aging, cancer, and genetic disorders such as tuberous sclerosis (TS), a rare neurodevelopmental multisystemic disease characterized by benign tumors, seizures, and intellectual disability. Although patches of white hair on the scalp (poliosis) are considered as early signs of TS, the underlying molecular mechanisms and potential involvement of mTORC1 in hair depigmentation remain unclear. Here, we have used healthy, organ-cultured human scalp hair follicles (HFs) to interrogate the role of mTORC1 in a prototypic human (mini-)organ. Gray/white HFs exhibit high mTORC1 activity, while mTORC1 inhibition by rapamycin stimulated HF growth and pigmentation, even in gray/white HFs that still contained some surviving melanocytes. Mechanistically, this occurred via increased intrafollicular production of the melanotropic hormone, α-MSH. In contrast, knockdown of intrafollicular TSC2, a negative regulator of mTORC1, significantly reduced HF pigmentation. Our findings introduce mTORC1 activity as an important negative regulator of human HF growth and pigmentation and suggest that pharmacological mTORC1 inhibition could become a novel strategy in the management of hair loss and depigmentation disorders.
Topics: Humans; Hair Follicle; Mechanistic Target of Rapamycin Complex 1; Pigmentation; Melanocytes; Hair Color
PubMed: 37212043
DOI: 10.15252/embr.202256574 -
Dermatologic Clinics Jan 2020Phototherapy in skin of color requires special consideration. Pigmented skin is an efficient ultraviolet filter. Hence, higher doses of ultraviolet radiation are... (Review)
Review
Phototherapy in skin of color requires special consideration. Pigmented skin is an efficient ultraviolet filter. Hence, higher doses of ultraviolet radiation are generally more effective and well tolerated in skin of color. An objective and practical system has not yet been established to determine optimal phototherapy dosing in skin of color. The authors recommend obtaining a detailed history of each individual patient's response to sun exposure before prescribing a phototherapy dosing regimen. In addition, providers should consider the role of socioeconomic factors and their impact on phototherapy-related outcomes, including barriers to access and compliance.
Topics: Humans; Phototherapy; Pigmentation Disorders; Skin Pigmentation
PubMed: 31753193
DOI: 10.1016/j.det.2019.08.006