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International Journal of Molecular... Apr 2021The production of melanin pigments by melanocytes and their quantity, quality, and distribution play a decisive role in determining human skin, eye, and hair color, and... (Review)
Review
The production of melanin pigments by melanocytes and their quantity, quality, and distribution play a decisive role in determining human skin, eye, and hair color, and protect the skin from adverse effects of ultraviolet radiation (UVR) and oxidative stress from various environmental pollutants. Melanocytes reside in the basal layer of the interfollicular epidermis and are compensated by melanocyte stem cells in the follicular bulge area. Various stimuli such as eczema, microbial infection, ultraviolet light exposure, mechanical injury, and aging provoke skin inflammation. These acute or chronic inflammatory responses cause inflammatory cytokine production from epidermal keratinocytes as well as dermal fibroblasts and other cells, which in turn stimulate melanocytes, often resulting in skin pigmentation. It is confirmed by some recent studies that several interleukins (ILs) and other inflammatory mediators modulate the proliferation and differentiation of human epidermal melanocytes and also promote or inhibit expression of melanogenesis-related gene expression directly or indirectly, thereby participating in regulation of skin pigmentation. Understanding of mechanisms of skin pigmentation due to inflammation helps to elucidate the relationship between inflammation and skin pigmentation regulation and can guide development of new therapeutic pathways for treating pigmented dermatosis. This review covers the mechanistic aspects of skin pigmentation caused by inflammation.
Topics: Aging; Cell Differentiation; Humans; Inflammation; Keratinocytes; Melanins; Melanocytes; Skin; Skin Pigmentation; Ultraviolet Rays
PubMed: 33921371
DOI: 10.3390/ijms22083970 -
Annals of Botany Nov 2022Land plants commonly produce red pigmentation as a response to environmental stressors, both abiotic and biotic. The type of pigment produced varies among different land... (Review)
Review
BACKGROUND
Land plants commonly produce red pigmentation as a response to environmental stressors, both abiotic and biotic. The type of pigment produced varies among different land plant lineages. In the majority of species they are flavonoids, a large branch of the phenylpropanoid pathway. Flavonoids that can confer red colours include 3-hydroxyanthocyanins, 3-deoxyanthocyanins, sphagnorubins and auronidins, which are the predominant red pigments in flowering plants, ferns, mosses and liverworts, respectively. However, some flowering plants have lost the capacity for anthocyanin biosynthesis and produce nitrogen-containing betalain pigments instead. Some terrestrial algal species also produce red pigmentation as an abiotic stress response, and these include both carotenoid and phenolic pigments.
SCOPE
In this review, we examine: which environmental triggers induce red pigmentation in non-reproductive tissues; theories on the functions of stress-induced pigmentation; the evolution of the biosynthetic pathways; and structure-function aspects of different pigment types. We also compare data on stress-induced pigmentation in land plants with those for terrestrial algae, and discuss possible explanations for the lack of red pigmentation in the hornwort lineage of land plants.
CONCLUSIONS
The evidence suggests that pigment biosynthetic pathways have evolved numerous times in land plants to provide compounds that have red colour to screen damaging photosynthetically active radiation but that also have secondary functions that provide specific benefits to the particular land plant lineage.
Topics: Anthocyanins; Embryophyta; Pigmentation; Betalains; Plants; Flavonoids
PubMed: 36070407
DOI: 10.1093/aob/mcac109 -
Journal of Neuroscience Research Jan 2019Albinism, typically characterized by decreased melanin synthesis, is associated with significant visual deficits owing to developmental changes during neurosensory... (Review)
Review
Albinism, typically characterized by decreased melanin synthesis, is associated with significant visual deficits owing to developmental changes during neurosensory retina development. All albinism is caused by genetic mutations in a group of diverse genes including enzymes, transporters, G-protein coupled receptor. Interestingly, these genes are not expressed in the neurosensory retina. Further, regardless of cause of albinism, all forms of albinism have the same retinal pathology, the extent of which is variable. In this review, we explore the possibility that this similarity in retinal phenotype is because all forms of albinism funnel through the same final common pathway. There are currently seven known genes linked to the seven forms of ocular cutaneous albinism. These types of albinism are the most common, and result in changes to all pigmented tissues (hair, skin, eyes). We will discuss the incidence and mechanism, where known, to develop a picture as to how the mutations cause albinism. Next, we will examine the one form of albinism which causes tissue-specific pathology, ocular albinism, where the eye exhibits the retinal albinism phenotype despite near normal melanin synthesis. We will discuss a potential way to treat the disease and restore normal retinal development. Finally, we will briefly discuss the possibility that this same pathway may intersect with the most common cause of permanent vision loss in the elderly.
Topics: Albinism, Ocular; Eye Proteins; Humans; Melanins; Membrane Glycoproteins; Mutation; Pigmentation; Retina; Retinal Pigment Epithelium
PubMed: 29761529
DOI: 10.1002/jnr.24246 -
American Journal of Physiology.... Sep 2019The vitamin D-folate hypothesis has been proposed as an explanation for the evolution of human skin pigmentation. According to this hypothesis, a darkened skin pigment... (Review)
Review
The vitamin D-folate hypothesis has been proposed as an explanation for the evolution of human skin pigmentation. According to this hypothesis, a darkened skin pigment was adapted by early human populations living in equatorial Africa to protect against photodegradation of bioavailable folate by ultraviolet radiation (UVR). As humans moved away from the equator to more northern latitudes and occupied regions of lower UVR exposure and greater seasonal variation, however, depigmentation occurred to allow for adequate biosynthesis of vitamin D. Vitamin D and folate are both recognized for their evolutionary importance in healthy pregnancy and early childhood development. More recently, evidence has emerged demonstrating the importance of both vitamin D and folate in vascular health via their effects in reducing oxidative stress and improving nitric oxide (NO) bioavailability. Thus, populations with darkened skin pigmentation may be at elevated risk of vascular dysfunction and cardiovascular disease in low UVR environments due to hypovitaminosis D; particularly important as darkly-pigmented African-Americans represent an at-risk population for cardiovascular disease. Conversely, lightly pigmented populations in high UVR environments may be at risk of deleterious vascular effects of UVR-induced folate degradation. The focus of this review is to explore the currently available literature regarding the potential role of UVR in vascular health via its differential effects on vitamin D and folate metabolism, as well as the interaction between skin pigmentation, genetics, and environment in modulating the vascular influence of UVR exposure.
Topics: Biological Evolution; Cardiovascular Diseases; Folic Acid; Humans; Skin Pigmentation; Ultraviolet Rays; Vitamin D
PubMed: 31314544
DOI: 10.1152/ajpregu.00136.2019 -
Development, Growth & Differentiation Jun 2020Fruit flies (Drosophila and its close relatives, or "drosophilids") are a group that includes an important model organism, Drosophila melanogaster, and also very diverse... (Review)
Review
Fruit flies (Drosophila and its close relatives, or "drosophilids") are a group that includes an important model organism, Drosophila melanogaster, and also very diverse species distributed worldwide. Many of these species have black or brown pigmentation patterns on their wings, and have been used as material for evo-devo research. Pigmentation patterns are thought to have evolved rapidly compared with body plans or body shapes; hence they are advantageous model systems for studying evolutionary gains of traits and parallel evolution. Various groups of drosophilids, including genus Idiomyia (Hawaiian Drosophila), have a variety of pigmentations, ranging from simple black pigmentations around crossveins to a single antero-distal spot and a more complex mottled pattern. Pigmentation patterns are sometimes obviously used for sexual displays; however, in some cases they may have other functions. The process of wing formation in Drosophila, the general mechanism of pigmentation formation, and the transport of substances necessary for pigmentation, including melanin precursors, through wing veins are summarized here. Lastly, the evolution of the expression of genes regulating pigmentation patterns, the role of cis-regulatory regions, and the conditions required for the evolutionary emergence of pigmentation patterns are discussed. Future prospects for research on the evolution of wing pigmentation pattern formation in drosophilids are presented, particularly from the point of view of how they compare with other studies of the evolution of new traits.
Topics: Animals; Biological Evolution; Drosophila melanogaster; Gene Expression Regulation, Developmental; Pigmentation; Wings, Animal
PubMed: 32171022
DOI: 10.1111/dgd.12661 -
Current Opinion in Genetics &... Aug 2021The order Odonata (dragonflies and damselflies) comprises diurnal insects with well-developed vision, showing diverse colors in adult wings and bodies. It is one of the... (Review)
Review
The order Odonata (dragonflies and damselflies) comprises diurnal insects with well-developed vision, showing diverse colors in adult wings and bodies. It is one of the most ancestral winged insect groups. Because Odonata species use visual cues to recognize each other, color patterns have been investigated from ecological and evolutionary viewpoints. Here we review the recent progress on molecular mechanisms of pigmentation, especially focused on light-blue coloration. Results from histology and pigment analysis showed that ommochrome pigments on the proximal layer and pteridine pigments on the distal layer of the epidermis are essential for light-blue coloration. We also summarize genes involved in the biosynthesis of three major insect pigments conserved across insects and discuss that gene-functional analysis deserves future studies.
Topics: Animals; Color; Odonata; Phenothiazines; Phenotype; Pigmentation; Wings, Animal
PubMed: 33482606
DOI: 10.1016/j.gde.2020.12.014 -
Sheng Wu Gong Cheng Xue Bao = Chinese... Jun 2021Since synthetic pigments are potentially harmful to human health, natural ones such as bixin, one of the carotenoids, are favored. As the second widely used natural... (Review)
Review
Since synthetic pigments are potentially harmful to human health, natural ones such as bixin, one of the carotenoids, are favored. As the second widely used natural pigment in the world, there is significant interest in the biosynthetic pathway of bixin which has not been fully elucidated. This review summarizes the chemical properties, extraction methods, biosynthetic pathway and application of bixin. In addition, we compared the difference between traditional extraction methods and new extraction techniques. Moreover, we described the genes involved in the biosynthetic pathway of bixin and the effects of abiotic stress on the biosynthesis of bixin, and discussed the application of bixin in food, pharmaceutical and chemical industries. However, the researches on bixin biosynthesis pathway are mostly carried out at the transcriptome level and most of the gene functions have not been elucidated. Therefore, we propose to characterize the entire bixin biosynthetic pathway using techniques of genomics, bioinformatics, and phytochemistry. This will help facilitate the synthetic biology research of bixin and development of bixin into new drugs.
Topics: Bixaceae; Carotenoids; Humans; Pigmentation; Transcriptome
PubMed: 34227289
DOI: 10.13345/j.cjb.200724 -
Marine Drugs Aug 2022For more than 40 years, marine microorganisms have raised great interest because of their major ecological function and their numerous applications for biotechnology and... (Review)
Review
For more than 40 years, marine microorganisms have raised great interest because of their major ecological function and their numerous applications for biotechnology and pharmacology. Particularly, Archaea represent a resource of great potential for the identification of new metabolites because of their adaptation to extreme environmental conditions and their original metabolic pathways, allowing the synthesis of unique biomolecules. Studies on archaeal carotenoids are still relatively scarce and only a few works have focused on their industrial scale production and their biotechnological and pharmacological properties, while the societal demand for these bioactive pigments is growing. This article aims to provide a comprehensive review of the current knowledge on carotenoid metabolism in Archaea and the potential applications of these pigments in biotechnology and medicine. After reviewing the ecology and classification of these microorganisms, as well as their unique cellular and biochemical characteristics, this paper highlights the most recent data concerning carotenoid metabolism in Archaea, the biological properties of these pigments, and biotechnological considerations for their production at industrial scale.
Topics: Archaea; Biotechnology; Carotenoids; Pigmentation
PubMed: 36005527
DOI: 10.3390/md20080524 -
Archives of Biochemistry and Biophysics Dec 2014MITF and pigmentation play important roles in both normal melanocyte and transformed melanoma cell biology. MITF is regulated by many pathways and it also regulates many... (Review)
Review
MITF and pigmentation play important roles in both normal melanocyte and transformed melanoma cell biology. MITF is regulated by many pathways and it also regulates many targets, some of which are still being discovered and functionally validated. MITF is involved in a wide range of processes in melanocytes, including pigment synthesis and lineage survival. Pigmentation itself plays an important role as the interface between genetic and environmental factors that contribute to melanoma.
Topics: Animals; Carcinogenesis; Cell Cycle; Cell Movement; Cell Survival; Cell Transformation, Neoplastic; Humans; Melanins; Melanocytes; Melanoma; Microphthalmia-Associated Transcription Factor; Neoplasm Invasiveness; Oxidative Stress; Pigmentation; Skin Neoplasms
PubMed: 25111671
DOI: 10.1016/j.abb.2014.07.019 -
Physiological Measurement Jun 2023. Pulse oximetry is a non-invasive optical technique used to measure arterial oxygen saturation (SpO) in a variety of clinical settings and scenarios. Despite being one... (Review)
Review
. Pulse oximetry is a non-invasive optical technique used to measure arterial oxygen saturation (SpO) in a variety of clinical settings and scenarios. Despite being one the most significant technological advances in health monitoring over the last few decades, there have been reports on its various limitations. Recently due to the Covid-19 pandemic, questions about pulse oximeter technology and its accuracy when used in people with different skin pigmentation have resurfaced, and are to be addressed.. This review presents an introduction to the technique of pulse oximetry including its basic principle of operation, technology, and limitations, with a more in depth focus on skin pigmentation. Relevant literature relating to the performance and accuracy of pulse oximeters in populations with different skin pigmentation are evaluated.. The majority of the evidence suggests that the accuracy of pulse oximetry differs in subjects of different skin pigmentations to a level that requires particular attention, with decreased accuracy in patients with dark skin.. Some recommendations, both from the literature and contributions from the authors, suggest how future work could address these inaccuracies to potentially improve clinical outcomes. These include the objective quantification of skin pigmentation to replace currently used qualitative methods, and computational modelling for predicting calibration algorithms based on skin colour.
Topics: Humans; Skin Pigmentation; Pandemics; COVID-19; Oximetry; Oxygen
PubMed: 37172609
DOI: 10.1088/1361-6579/acd51a