Vichy Exposome Grant

There is an increasing awareness that air pollution may increase the risk of development and exacerbation of dermatological diseases. The harmful impact of airborne pollutants on skin diseases might be derived from different pathomechanisms including skin barrier dysfunction, oxidative damage, immune stimulation, and dysbiosis. Trimethylamine (TMA) is a universal air pollutant as well as active molecule produced by microbiota. So far, TMA and its metabolites were evaluated in cardiovascular disorders. Although, their harmful pleiotropic effects may also affect skin.

Therefore, the aim of this project is to examine the role of trimethylamine (an air pollutant and gut microbiota-derived metabolite) in different inflammatory diseases, namely psoriasis and atopic dermatitis. In vitro studies evaluate the role of different TMA concentrations on T lymphocytes activation, proliferation, and cytokines synthesis. Role of saliva as an additional source for TMA concentration assessment will be also studied.

Our data might yield a new insight into the role of exposome in inflammatory diseases pathogenesis, which contributes to development of novel therapeutic strategies.

Androgenetic alopecia (AGA) is characterized by a progressive miniaturization of hair follicles caused by androgens in genetically susceptible women and men. Menopause is a critical stage of female reproductive ageing and health, and it is defined as the permanent cessation of menstruation resulting from the loss of ovarian follicular activity. Skin and hair involvement often receive less attention than other menopausal symptoms despite having a significant negative effect on quality of life. Moreover, depressive and anxiety symptoms are more common during postmenopausal stage. The hormone replacement therapy is not indicated for skin and hair symptoms alone due to the low risk–benefit balance.

The aims of our study are (i) to evaluate the impact of menopause on the severity of AGA, (ii) to investigate the clinical and trichoscopy pattern of AGA in post-menopausal female (iii) to evaluate the impact of menopause on QoL, depressive and anxiety symptoms in patients with AGA and (iv) to compare AGA clinical and trichoscopy pattern and QoL, anxiety and depressive symptoms in those treated with hormone replacement therapy versus those not treated in a real world setting.

The study of the skin-gut axis is increasingly important due to its potential therapeutic implications and lifestyle interventions that can yield results in skin health¹ One of the most prevalent skin diseases with important public health implications is atopic dermatitis (AD) and, recently, the influence of the gut and its microbiome on this disease has emerged as a novel, dynamic and promising field of research²

The effect of parasites on AD remains unclear. These microorganisms have been poorly studied, and their role in the disease is far from being understood³ Some studies indicate that infections with certain helminths may provide protection against allergic disorders⁴, while others may increase the risk of developing the disease⁵ Associations between AD and protozoa has also been observed⁶

The objective of this study is to investigate the interaction between intestinal parasites and the gut bacterial microbiome and understand how this component of the "internal" exposome influences the skin-gut axis in the disease. This will be accomplished through extensive sociodemographic characterization, examination of relevant variables associated with the disease, and analysis of the "external" exposome in individuals with varying severities of AD.

Additionally, stool samples will be collected for the diagnosis of intestinal parasites (by microscopy and PCR) and the analysis of the bacterial microbiome (by NGS). The obtained data will undergo comprehensive bioinformatics analysis to characterize the "internal" exposome in detail.

1. Mahmud MdR, Akter S, Tamanna SK, et al. Impact of gut microbiome on skin health: gut-skin axis observed through the lenses of therapeutics and skin diseases. Gut Microbes. 2022;14(1). doi:10.1080/19490976.2022.2096995
2. Lee SY, Lee E, Park YM, Hong SJ. Microbiome in the Gut-Skin Axis in Atopic Dermatitis. Allergy Asthma Immunol Res. 2018;10(4):354-362. doi:10.4168/aair.2018.10.4.354
3. Feary J, Britton J, Leonardi-Bee J. Atopy and current intestinal parasite infection: a systematic review and meta-analysis. Allergy. 2011;66(4):569-578. doi:10.1111/j.1398-9995.2010.02512.x
4. Salem I, Ramser A, Isham N, Ghannoum MA. The Gut Microbiome as a Major Regulator of the Gut- Skin Axis. Front Microbiol. 2018;9. doi:10.3389/fmicb.2018.01459
5. Ellis SR, Nguyen M, Vaughn AR, et al. The Skin and Gut Microbiome and Its Role in Common Dermatologic Conditions. Microorganisms. 2019;7(11). doi:10.3390/microorganisms7110550
6. McKenzie C, Tan J, Macia L, Mackay CR. The nutrition-gut microbiome-physiology axis and allergic diseases. Immunol Rev. 2017;278(1):277-295. doi:10.1111/imr.12556

Rosacea is a common chronic inflammatory skin and eye disease that primarily affects the center of the face (although extra-facial manifestations occur, also). It is characterized by symptoms such as erythema, edema, telangiectasias, papules and pustules. While the exact causes of rosacea are not fully understood, it is believed to be influenced by various factors including immunological and genetic factors, vascular dysregulation, environmental triggers, dietary factors, and the action of microorganisms. Recent studies have also highlighted the role of the intestinal microbiome in the development of rosacea, possibly through the stimulation of the mTOR pathway. There is an increased incidence of rosacea in individuals with gastrointestinal, neurological, and cardiovascular diseases and patients with rosacea have been found to have higher levels of cathelicidins (antimicrobial and pro-inflammatory peptides).

Building upon this background, the present project aims to investigate the relationship between comorbidities, microbiome profile, serum cathelicidin levels, and diet in patients with rosacea. This case-control study will involve the clinical and laboratory evaluation of patients with rosacea and include the analysis of fecal samples to determine the composition of the intestinal microbiota, a food questionnaire to assess dietary patterns, and the measurement of serum cathelicidin levels. These investigations are intended to provide a better understanding of the underlying mechanisms involved in the pathogenesis of rosacea, as well as its potential systemic implications.

Parasites have been proposed as an important component of the exposome in Atopic Dermatitis (AD), mainly because of their capacity to regulate the immune response¹. However, the evidence supporting this proposal is based on epidemiological studies, where contradictory results have been found in some populations² Very few studies have been conducted to evaluate the impact of intestinal parasites on skin immunology, so the role of this component of the exposome in the pathophysiology of AD is still poorly understood³ Immunoglobulin A (IgA) is the most important immunoglobulin in the mucosal system⁴ The secretory component of IgA (SIgA) has been identified as a protective factor in some inflammatory diseases⁵ The changes and the effect that intestinal parasites and other components of the exposome may have on SIgA levels in AD have not been studied.

The objective of this study is to explore the impact of parasites and other components of the exposome on SIgA levels in patients with AD stratified by severity. This will be achieved through an extensive and in-depth analysis of key exposome components that may impact immunoglobulin levels and parasites. Subsequently, direct parasitological diagnosis will be performed on stool samples, and serum SIgA quantification will be measured using ELISA. Statistical analyses will be conducted to identify exposome variables associated with potential changes in SIgA, while taking disease severity into account.

1. Okada H, Kuhn C, Feillet H, Bach JF. The ‘hygiene hypothesis’ for autoimmune and allergic diseases: an update. Clin Exp Immunol. 2010;160(1):1-9. doi:10.1111/j.1365-2249.2010.04139.x
2. Briggs N, Weatherhead J, Sastry KJ, Hotez PJ. The Hygiene Hypothesis and Its Inconvenient Truths about Helminth Infections. PLoS Negl Trop Dis. 2016;10(9):e0004944. doi:10.1371/journal.pntd.0004944
3. Flohr C, Quinnell RJ, Britton J. Do helminth parasites protect against atopy and allergic disease? Clinical & Experimental Allergy. 2009;39(1):20-32. doi:10.1111/j.1365-2222.2008.03134.x
4. Cerutti A, Rescigno M. The Biology of Intestinal Immunoglobulin A Responses. Immunity. 2008;28(6):740-750. doi:10.1016/j.immuni.2008.05.001
5. Mantis NJ, Rol N, Corthésy B. Secretory IgA’s complex roles in immunity and mucosal homeostasis in the gut. Mucosal Immunol. 2011;4(6):603-611. doi:10.1038/mi.2011.41

Atopic dermatitis (AD) is a chronic inflammatory skin disorder characterized by intense itching, dysregulated immune responses, disruption of the skin barrier, and skin dysbiosis, including Staphylococcus aureus (S. aureus) overexposure. Hence, AD is uniquely poised for skin exposomal research. Betacellulin (BTC), a peptide ligand of epidermal growth factor receptor (EGFR), regulates skin proliferation and hemostasis and protects against inflammation in pancreatitis. Moreover, EGFR signaling relieves S. aureus-induced inflammatory signals in human epidermal keratinocytes and AD-like skin lesions in mice. However, the potential role of BTC on exposure-induced skin barrier dysfunction and inflammation in AD remains unclear.

To determine the role of BTC in skin exposome regulation, I will establish S. aureus-induced AD-like human skin equivalent models to examine the alteration of S. aureus inoculation, skin barrier function and skin inflammation following treatment with BTC in the presence or absence of an EGFR inhibitor, erlotinib. While most studies focus on cytokine-targeted therapies, this study instead aims to identify new therapeutic targets that directly regulate S. aureus exposure to inhibit inflammation and restore skin barrier function through EGFR regulation. The proposed study will address the significant unmet need to improve AD management through an exposomal approach.

Scalp health has lately attracted the public attention, because of its contribution to optimal hair growth, which is crucial to our physical appearance and self-perception. As the first line of physical defense against stressors, scalp and hair are affected by multiple exposome factors. Both internal factors such as aging and hormone and external factors like UV radiation (UVR) may influence scalp health.

Dandruff and seborrheic dermatitis (D/SD) are a common scalp condition frequently seen in clinical practice and have a huge impact on our quality of life. The exact pathophysiology of D/SD is poorly understood. Besides Malassezia spp. and its interaction with skin immune system, environmental factors including UVR, and low vitamin D levels might also be involved in D/SD. It is reported that scalp and hair in D/SD patients exhibit clear signs of oxidative stress.

Currently the systematic effects of exposome on scalp health in Asian populations remain unknown. To fill the gap, we aim to investigate the scalp condition of the Chinese female population. Using D/SD as a model, we will study the combined effect of external (UVR) and internal exposure factors (hormone, age, vitamin D) on scalp health. These findings will help better understand the impact of exposome on scalp health, particularly for the population in China.

Host defense (antimicrobial) peptides (HDPs) constitute a crucial part of the epidermal innate immunity and function as the foremost barrier against external environmental threats. Human β-defensins (hBDs), one of the major families of HDPs found in mammals, are multi-functional cationic peptides expressed by various cell types including cells in the skin epithelia. Although hBDs are known to exhibit many immunomodulatory functions, the photo-protective effects of hBDs have never been explored before in the literature. Therefore, we aim to investigate the potential roles of hBDs on human dermal fibroblasts in UVB-induced photoaging. Discovering novel functions of hBDs will not only implement the basic knowledge in immunodermatology, but also enlighten physicians to develop promising treatment strategies for patients with photodermatoses.

Chronic spontaneous urticaria (CSU) often exhibits skin manifestations that often heavily impair the quality of life. However, its exact etiology needs to be determined. Pathologically, CSU can be subdivided into endotypes of autoallergy or autoimmunity. In autoallergic CSU patients, IgE antibodies against body-own antigens, such as thyroid peroxidase (TPO) and interleukin-24 (IL-24) are formed. We hypothesize that IgE that binds TPO and IL-24 actually targets bacterial antigens the body is exposed to, which carry similar epitopes as these human proteins.

Therefore, CSU might develop due to formation of IgE tackling a bacterial infection, which (unintendedly) cross-react with autoantigens. Several indications support our theory: First, IgE specific for bacterial antigens has already been described in Staphylococcus aureus infections 1. Thus, IgE formation could as well be a defense mechanism for other bacterial species. Second, antibiotic treatment, showed improvement in some CSU patients 2. Third, a spontaneous remission is observed in 80 % of CSU patients within five years, which might be due to the resolution of a certain bacterial infection. Fourth, ultraviolet (UV)B-radiation treatment is effective in CSU patients and can alter the microbial composition on the skin 3,4.

Thus, we will look for a bacterial component in the skin and beyond in the pathogenesis of autoallergic CSU. Our results will help to unravel the etiology of CSU and develop new strategies for prophylaxis and treatment.

Exposome factors can damage the skin by altering skin homeostasis and epidermal barrier (EB) function.

Sun exposure, air pollution, cigarette smoke, hormone exposure, the diet and sleep disturbances are exposome factor that may impair EB. Assessment of the EB usually involves measurements of Transepidermal Water Loss (TEWL). Stratum corneum hydration (SCH), skin surface pH, temperature, elasticity, melanin, erythema, skin gloss, stiffness and deformability are other factors to assess EB function. We previously found that age, sun and tobacco were associated with skin ageing and that a skin care routine delayed skin ageing.

Moreover, we observed that UVB changes skin homeostasis and EB function in psoriatic patients. Recently, it has been described that human tissue engineering skin substitute (hTESS) are exemplary models for evaluating the impact of extrinsic factors on the skin. We have manufactured a new hTESS with fibrin-hyaluronic acid (HA) biomaterial suitable for wound healing and we have tested the impact of different chemical products on hTESS. It is important to evaluate the impact of exposome factors both in vitro and in vivo. Knowing how each factor damage the skin and what are the most harmful, would help researchers to develop products that decrease EB impairment.

The aim of this project is to investigate skin homeostasis alterations and EB disruption induced by exposome factors both in vitro using hTESSs and in vivo evaluating healthy volunteers.

Plastic-based products are ubiquitous due to their tremendous utility in our daily lives. However, the limited biodegradable nature of plastics, especially micro- and nanoplastics (MPs/NPs), has recently raised global pollution concerns. These anthropogenic pollutants, currently widespread in the oceans, freshwater bodies, land or even present in food, are either manufactured specifically in the small size range for various commercial applications or formed due to fragmentation of macroplastics in the environment.

The biological effects of MPs and NPs on aquatic organisms are well documented but their impacts on the mammalian system have not been deeply investigated and data on the impact on the human body at subcellular or molecular levels is scarce. In particular, the penetration of these particles through the skin epithelia and their effect on skin health has not been examined thoroughly.

Therefore, going behind the state of the art, this project aims to elucidate the potential pathological events triggered by different MPs/NPs on skin with focus on oxidative and inflammatory damages, as well as aging-related events, at different levels of biological complexity (molecular, cellular and organ levels).

Ultimately, this proposal will allow to identify the adverse outcome pathway (AOP) triggered by MPs/NPs exposome at the skin level.

An individual's exposome is highly dynamic, with transient responses to stressors throughout the lifetime. Evaluating the impact of such exposures and their consequences is challenging. We argue that proteomic / metabolomic-based mass spectrometry should be a method of choice for assessing a skin's health and its transients. Only proteomics can, for example, capture protein post-translational modifications that have been extensively used in correlation with skin conditions. We obtain the shotgun proteomic and metabolomic skin profiles from nearly 200 human donors aged 20 to 80 using nano- chromatography coupled with an Orbitrap Lumos mass spectrometer.

This project aims to develop an artificial neural network (ANN) able to learn from these spectra to, ultimately, enable scoring an unknown skin profile according to relative age. In what follows, in a real but controlled experiment for validation, we will acquire the skin profiles from another 40 subjects of roughly the same age (~35yr) that are highly exposed (or not) to sun radiation. We expect our ANN to provide a higher score for those that are daily exposed to the radiation. We will also pinpoint differentially abundant proteins.

We anticipate our method should be of immediate and broad applicability for evaluating scientific assessments related to skin exposures and health, such as the accelerated exposome effects of pollution or the benefits of skin treatments in clinical science.

Melasma is a chronic skin disorder that mainly affects women during fertile age, and its pathogenesis is still not fully understood. Sun exposure is the major risk factor for melasma development. It induces a skin stress response that causes premature cellular senescence and can activate Aryl Hydrocarbon Receptor (AhR). When AhR is activated, it promotes upregulation of tyrosinase. AhR is an exposome receptor, because it is activated by a variety of ligands, including xenobiotics (as dioxins and other polycyclic aromatic hydrocarbons), natural products, microbiome metabolites, and endogenous molecules.

A significant increase in the incidence of melasma is well documented in the past decade, especially in urban areas where air pollution also increased. Air pollution plays an important role in extrinsic aging and pigmentation. Until now, AhR expression has never been evaluated in melanocytes and keratinocytes from melasma skin. This study aims to evaluate the expression of AhR in keratinocytes, basal layer melanocytes, and pendulum melanocytes from the facial melasma skin of women compared to the expression in adjacent healthy skin.

Twenty women will be biopsied in two different areas: melasma and healthy adjacent skin. Fragments will be submitted to triple-labeled immunofluorescence: anti-AhR, anti-vimentin and DAPI. The slides will be photographed at a confocal microscopy equipment and semiquantitative blind analysis will be performed on suprabasal keratinocytes, basal layer melanocytes and pendulum melanocytes (nucleus and cytoplasm).

Atopic dermatitis (AD) is a common chronic inflammatory skin disease that mainly affects the urban population and is characterized by pruritic eczematous lesions. Since the disease is associated with dysbiosis, selective modulation of the microbiota of each patient has become a topic of great interest. In this context, knowing the relationship between exposome atmospheric pollution and the microbiota of atopic patients is part of the process for a better selective modulation of microorganisms found in the skin. Given the above, this project aims to evaluate the skin microbiota of patients, children, and adults, diagnosed with AD in two different cities, one with high and the other with low level of pollution.

Skin microbiome exerts a major role in maintaining tissue homeostasis, educating, and modulating immune responses or contributing to various cutaneous pathologies. We have recently shown in preclinical models that skin microbiome significantly hampers the immunosuppressive effects of ultraviolet radiation (UVR). However, the nature of the microbes which inhibit UVR effects, and their underlying mechanisms remains to be uncovered. In the proposed project, we hypothesize that specific cutaneous bacteria impede UV functions through their ability to metabolize cis-urocanic acid (cis-UCA), one of the major immunosuppressive metabolites produced upon UV exposure. We will then examine different bacterial species from the Cyanobacteria and Bacteroidetes phyla, which increased in their abundance upon UV exposure, for their capacity to capture and isomerize trans-UCA, the precursor of cis-UCA.

We will determine whether they use cis-UCA for their growth, survival, and/or to acquire pathogenic features through the production of virulence factors. In second step of the project, we will examine the capacity of the respective bacteria to prevent the immunomodulatory effects of cis-UCA on reconstructed human epidermis. Finally, we will test for different inhibitors that modulate the metabolism of urocanate pathway to restore the immunosuppressive properties of cis-UCA. Our results should bring major insight to better understand how skin microbiome regulate immune responses at the skin interface, and open avenues to optimize the therapeutic protocols which utilize the immunomodulatory properties of UVR.

Skin aging is an important health issue and public concern. In the real world, the body’s skin is exposed to the mixture of different air pollutants and climatic conditions (e.g., ambient heat) rather than a single environmental factor. Although the individual impact of these hazards on skin aging has been discussed, their interactive and combined effects remain largely unclear. As a result, the role of exposome on skin aging may have been underestimated. The lack of investigation is particularly true in China – a country is facing a heavy health burden from air pollution exposure, climate change, and population aging.

To fill the research gap, this project will explore the independent, interactive, and combined effects of chronic exposure to different air pollutants (i.e., particulate matter, nitrogen dioxide, and ozone) and ambient heat on skin aging in the Chinese elderly. The project will make use of the Taizhou study cohort. Located at the junction of north and south China, Taizhou is in the middle of the spectrum – both geographically, climatically, and genetically, which promises the representativeness of our results. The findings will help to understand the impact of environmental factors as a whole on skin aging in Chinese elderly.

Research on skin health involve interdisciplinary subjects. On the one hand, the individual's behavior, lifestyle and genetic factors. On the other hand, external factors such as exposure to the sun, weather and air pollution. The lack of studies that integrate these intrinsic and extrinsic factors limit the advance of knowledge about skin health. This lack is due to several factors, such as:
a) difficulties in integrating interdisciplinary research;
b) the limited use of recent data analysis tools (data mining, big data, machine learning, etc.);
c) the high cost of collecting, storing and transmitting data provided by obsolete systems; and, specifically related to the extrinsic aspects,
d) the lack of consistent meteorological measurement networks, mainly in less developed countries.

This research project aims to integrate low-cost environmental measurements, data transmission systems and data analysis to provide scientific and educational information for the industry, scientists and society. For this purpose, we propose an experimental set of environmental measurements based on a new generation of low-cost instruments and wireless data transmission performed in different Brazilian regions. In parallel, studies on photoprotection behavior and skin damage can be conducted in these areas. These data will feed a database for deep analysis based on statistical tools. This research project will be conducted by a multidisciplinary team involving physicists, doctors, chemists and engineers. We hope that this interdisciplinary effort can bring relevant contributions for the understanding of skin exposome.