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ELife Jun 2021Hair greying is a hallmark of aging generally believed to be irreversible and linked to psychological stress.
BACKGROUND
Hair greying is a hallmark of aging generally believed to be irreversible and linked to psychological stress.
METHODS
Here, we develop an approach to profile hair pigmentation patterns (HPPs) along individual human hair shafts, producing quantifiable physical timescales of rapid greying transitions.
RESULTS
Using this method, we show white/grey hairs that naturally regain pigmentation across sex, ethnicities, ages, and body regions, thereby quantitatively defining the reversibility of greying in humans. Molecularly, grey hairs upregulate proteins related to energy metabolism, mitochondria, and antioxidant defenses. Combining HPP profiling and proteomics on single hairs, we also report hair greying and reversal that can occur in parallel with psychological stressors. To generalize these observations, we develop a computational simulation, which suggests a threshold-based mechanism for the temporary reversibility of greying.
CONCLUSIONS
Overall, this new method to quantitatively map recent life history in HPPs provides an opportunity to longitudinally examine the influence of recent life exposures on human biology.
FUNDING
This work was supported by the Wharton Fund and NIH grants GM119793, MH119336, and AG066828 (MP).
Topics: Adolescent; Adult; Aging; Child; Chromosome Mapping; Hair; Hair Color; Humans; Middle Aged; Stress, Psychological; Young Adult
PubMed: 34155974
DOI: 10.7554/eLife.67437 -
Cells Sep 2022Autophagy is a vital process for cell survival and it preserves homeostasis by recycling or disassembling unnecessary or dysfunctional cellular constituents. Autophagy... (Review)
Review
Autophagy is a vital process for cell survival and it preserves homeostasis by recycling or disassembling unnecessary or dysfunctional cellular constituents. Autophagy ameliorates skin integrity, regulating epidermal differentiation and constitutive pigmentation. It induces melanogenesis and contributes to skin color through melanosome turnover. Autophagy activity is involved in skin phenotypic plasticity and cell function maintenance and, if altered, it concurs to the onset and/or progression of hypopigmentary and hyperpigmentary disorders. Overexpression of autophagy exerts a protective role against the intrinsic metabolic stress occurring in vitiligo skin, while its dysfunction has been linked to the tuberous sclerosis complex hypopigmentation. Again, autophagy impairment reduces melanosome degradation by concurring to pigment accumulation characterizing senile lentigo and melasma. Here we provide an updated review that describes recent findings on the crucial role of autophagy in skin pigmentation, thus revealing the complex interplay among melanocyte biology, skin environment and autophagy. Hence, targeting this process may also represent a promising strategy for treating pigmentary disorders.
Topics: Autophagy; Humans; Hypopigmentation; Melanocytes; Pigmentation Disorders; Skin Pigmentation
PubMed: 36230960
DOI: 10.3390/cells11192999 -
Indian Pediatrics Apr 2024
Topics: Animals; Humans; Pigmentation; Heteroptera
PubMed: 38419280
DOI: No ID Found -
NTM Dec 2021
Topics: Ferrocyanides; Pigmentation
PubMed: 34491368
DOI: 10.1007/s00048-021-00311-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 -
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 -
Journal of Osteopathic Medicine Apr 2021
Topics: Animals; Citrus sinensis; Eyelids; Pigmentation; Poecilia
PubMed: 33878250
DOI: 10.1515/jom-2021-0076 -
The New Phytologist Oct 2019Within the angiosperm order Caryophyllales, an unusual class of pigments known as betalains can replace the otherwise ubiquitous anthocyanins. In contrast to the... (Review)
Review
Within the angiosperm order Caryophyllales, an unusual class of pigments known as betalains can replace the otherwise ubiquitous anthocyanins. In contrast to the phenylalanine-derived anthocyanins, betalains are tyrosine-derived pigments which contain the chromophore betalamic acid. The origin of betalain pigments within Caryophyllales and their mutual exclusion with anthocyanin pigments have been the subject of considerable research. In recent years, numerous discoveries, accelerated by -omic scale data, phylogenetics and synthetic biology, have shed light on the evolution of the betalain biosynthetic pathway in Caryophyllales. These advances include the elucidation of the biosynthetic steps in the betalain pathway, identification of transcriptional regulators of betalain synthesis, resolution of the phylogenetic history of key genes, and insight into a role for modulation of primary metabolism in betalain synthesis. Here we review how molecular genetics have advanced our understanding of the betalain biosynthetic pathway, and discuss the impact of phylogenetics in revealing its evolutionary history. In light of these insights, we explore our new understanding of the origin of betalains, the mutual exclusion of betalains and anthocyanins, and the homoplastic distribution of betalain pigmentation within Caryophyllales. We conclude with a speculative conceptual model for the stepwise emergence of betalain pigmentation.
Topics: Betalains; Biological Evolution; Biosynthetic Pathways; Caryophyllales; Phylogeny; Pigmentation
PubMed: 31172524
DOI: 10.1111/nph.15980