Corrigendum: Development of skin diseases following systemic exposure: example of dioxins.

[This corrects the article DOI: 10.3389/ftox.2023.

Development of skin diseases following systemic exposure: example of dioxins.

Most skin manifestations of exposure to toxic compounds are a consequence of a direct contact with the toxicants. However, some toxicants may reach the skin following systemic exposure, and promote skin diseases. Good examples of such chemicals are dioxin-like compounds.

Lipid Droplet Proteins in Acne Skin: A Sound Target for the Maintenance of Low Comedogenic Sebum and Acne-Prone Skin Health.

In adipocytes and sebocytes, lipid droplet proteins control the storage of lipids in organized droplets and their release on demand. The contribution of lipid droplet proteins to the pathogenesis of acne is plausible because they control the levels of comedogenic free fatty acids. The expression of two lipid droplet proteins, CIDEA and PLIN2, was analyzed in the skin of patients with acne by immunohistochemistry and western blotting.

Cytochrome P450 1A2 activity and incidence of thyroid disease and cancer after chronic or acute exposure to dioxins.

Background: Dioxin (2,3,7,8-tetrachlorodibenzo-p-dioxin; TCDD) is the most toxic congener of a family of structurally and mechanistically related persistent organic pollutants whose effects are mediated through the aryl hydrocarbon receptor (AhR). Induction of CYP1A1/2 by TCDD through the AhR depends on the magnitude and the duration of exposure. We aimed to assess CYP1A2 activity after acute and chronic exposure to TCDD.

Dermatoporosis, a prevalent skin condition affecting the elderly: current situation and potential treatments.

The term "dermatoporosis" was introduced a decade ago to highlight the need to pay attention to the problems posed by premature skin aging beyond esthetic considerations. People with this condition have a thinner skin that becomes fragile, tends to tear, and may lead to deep dissecting hematomas-as a final stage-corresponding to a medical emergency. Various studies have demonstrated a high prevalence of dermatoporosis in the elderly, with women being more exposed than men.

From the Cover: High Susceptibility of Lrig1 Sebaceous Stem Cells to TCDD in Mice.

We have previously shown that cytochrome P450 1A1 (CYP1A1) was highly induced for a long period of time in a patient who had been poisoned by 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD), a compound known to activate the aryl hydrocarbon receptor (AhR). During that period of time, no sebaceous glands could be observed in the skin of this patient. In this study, starting from observations in the patient exposed to TCDD, we analyzed the seboatrophy induced by dioxins in mice.

Evaluation and identification of dioxin exposure biomarkers in human urine by high-resolution metabolomics, multivariate analysis and in vitro synthesis.

A previous high-resolution metabolomic study pointed out a dysregulation of urinary steroids and bile acids in human cases of acute dioxin exposure. A subset of 24 compounds was highlighted as putative biomarkers. The aim of the current study was (i) to evaluate the 24 biomarkers in an independent human cohort exposed to dioxins released from the incineration fumes of a municipal waste incinerator and; (ii) to identify them by comparison with authentic chemical standards and biosynthesised products obtained with in vitro metabolic reactions.

Aryl Hydrocarbon Receptor Activation in Acne Vulgaris Skin: A Case Series from the Region of Naples, Italy.

Background: Dioxins are persistent organic pollutants present in the environment. They exert their biological effects by binding to an intracellular receptor, the aryl hydrocarbon receptor (AhR). Activation of AhR leads to the induction of cytochrome p450 1A1 (CYP1A1).

L-Tryptophan as a Novel Potential Pharmacological Treatment for Wound Healing via Aryl Hydrocarbon Receptor Activation.

Background: The aryl hydrocarbon receptor has been shown to be involved in wound healing.

Objective: The aim of this study was to assess the effect of tryptophan on wound healing in vitro and in a clinical trial.

Methods: The ability of tryptophan and 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD) to increase wound healing was assessed in an in vitro scratch wound model in human keratinocytes.

Topical retinoids in skin ageing: a focused update with reference to sun-induced epidermal vitamin A deficiency.

Vitamin A is an important constituent of the epidermis, where it plays a crucial role in epidermal turnover. A deficiency of epidermal vitamin A may be the consequence of nutritional vitamin A deficiency, exposure to sunlight or any UV source, oxidative stress or chronological ageing. As a consequence, any treatment aiming at increasing epidermal vitamin A would exert a protective effect against these deleterious conditions.

Activation of Nrf2 in keratinocytes causes chloracne (MADISH)-like skin disease in mice.

The transcription factor Nrf2 is a key regulator of the cellular stress response, and pharmacological Nrf2 activation is a promising strategy for skin protection and cancer prevention. We show here that prolonged Nrf2 activation in keratinocytes causes sebaceous gland enlargement and seborrhea in mice due to upregulation of the growth factor epigen, which we identified as a novel Nrf2 target. This was accompanied by thickening and hyperkeratosis of hair follicle infundibula.

AhR signalling and dioxin toxicity.

Dioxins are a family of molecules associated to several industrial accidents such as Ludwigshafen in 1953 or Seveso in 1976, to the Agent Orange used during the war of Vietnam, and more recently to the poisoning of the former president of Ukraine, Victor Yushchenko. These persistent organic pollutants are by-products of industrial activity and bind to an intracellular receptor, AhR, with a high potency. In humans, exposure to dioxins, in particular 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD) induces a cutaneous syndrome known as chloracne, consisting in the development of many small skin lesions (hamartoma), lasting for 2-5 years.

Human urinary biomarkers of dioxin exposure: analysis by metabolomics and biologically driven data dimensionality reduction.

Untargeted metabolomic approaches offer new opportunities for a deeper understanding of the molecular events related to toxic exposure. This study proposes a metabolomic investigation of biochemical alterations occurring in urine as a result of dioxin toxicity. Urine samples were collected from Czech chemical workers submitted to severe dioxin occupational exposure in a herbicide production plant in the late 1960s.

Interaction of ω-3 polyunsaturated fatty acids with radiation therapy in two different colorectal cancer cell lines.

Background & Aims: This study aims at evaluating if docosahexaenoic acid (DHA) or eicosapentaenoic acid (EPA) increases the efficacy of radiation therapy (RT) on two human colorectal cancer cell lines with different radio-sensitivity.

Methods: LS174T and HT-29 cells were treated with 20 or 50 μmol/L EPA or DHA followed by single X-ray RT of 0, 2 or 4 Gy, to evaluate cell survival, apoptosis, peroxide and malondialdehyde productions. Inflammation- and apoptosis-related proteins were analyzed by Western Blot.

Vitamin E content in fish oil emulsion does not prevent lipoperoxidative effects on human colorectal tumors.

Objective: The anticancer action exerted by polyunsaturated fatty acid peroxidation may not be reproduced by commercially available lipid emulsions rich in vitamin E. Therefore, we evaluated the effects of fish oil (FO) emulsion containing α-tocopherol 0.19 g/L on human colorectal adenocarcinoma cells and tumors.

Ebselen is a new skin depigmenting agent that inhibits melanin biosynthesis and melanosomal transfer.

We assessed the ability of ebselen, a glutathione peroxidase mimic, to reduce pigmentation in various models. In murine B16 melanocytes, 25 μm ebselen inhibited melanogenesis and induced a depolymerisation of actin filaments. In co-cultures of B16 melanocytes with BDVII keratinocytes, a pretreatment of melanocytes with ebselen resulted in a strong inhibition of melanosome transfer to keratinocytes, as shown under optical and electron microscopy.

A new spectrophotometric method for simple quantification of melanosomal transfer from melanocytes to keratinocytes.

Three major difficulties must be overcome to establish a quantitative method for melanosomal transfer analysis: (i) establishing a three-dimensional co-culture reassuring direct melanocyte to keratinocyte transfer, (ii) separation of melanocytes and keratinocytes following co-culture and (iii) melanosome quantification in each cell population. Melanocytes and keratinocytes are cultured on the opposite sides of the porous membrane of hanging cell inserts (1μm pores, 2×10(6) pores/cm(2) ). Cell separation is performed after 3days of co-culture by simple trypsinisation.

In vivo dioxin favors interleukin-22 production by human CD4+ T cells in an aryl hydrocarbon receptor (AhR)-dependent manner.

Background: The transcription factor aryl hydrocarbon receptor (AhR) mediates the effects of a group of chemicals known as dioxins, ubiquitously present in our environment. However, it is poorly known how the in vivo exposure to these chemicals affects in humans the adaptive immune response. We therefore assessed the functional phenotype of T cells from an individual who developed a severe cutaneous and systemic syndrome after having been exposed to an extremely high dose of 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD).

Synergistic effect of hyaluronate fragments in retinaldehyde-induced skin hyperplasia which is a Cd44-dependent phenomenon.

Background: CD44 is a polymorphic proteoglycan and functions as the principal cell-surface receptor for hyaluronate (HA). Heparin-binding epidermal growth factor (HB-EGF) activation of keratinocyte erbB receptors has been proposed to mediate retinoid-induced epidermal hyperplasia. We have recently shown that intermediate size HA fragments (HAFi) reverse skin atrophy by a CD44-dependent mechanism.

Activation of the aryl hydrocarbon receptor reveals distinct requirements for IL-22 and IL-17 production by human T helper cells.

Ligands of the aryl hydrocarbon receptor (AHR), a transcription factor mediating the effects of dioxin, favor Th17 differentiation and exacerbate autoimmunity in mice. We investigated how AHR ligands affected human T-cell polarization. We found that the high affinity and stable AHR-ligand dioxin as well as the natural AHR-ligand 6-formylinolo[3,2-b] carbazole induced the downstream AHR-target cytochrome P450A1, and without affecting IFN-gamma, they enhanced IL-22 while simultaneously decreasing IL-17A production by CD4(+) T cells.