A Genome-Wide Association Study of Basal Transepidermal Water Loss Finds that Variants at 9q34.3 Are Associated with Skin Barrier Function

Evaluation of Personalized Skincare Through in-silico Gene Interactive Networks and Cellular Responses to UVR and Oxidative Stress

Purpose

Personalized approaches in dermatology are designed to match the specific requirements based on the individual genetic makeup. One major factor accounting for the differences in skin phenotypes is single nucleotide polymorphism (SNP) within several genes with diverse roles that extend beyond skin tone and pigmentation. Therefore, the cellular sensitivities to the environmental stress and damage linked to extrinsic aging could also underlie the individual characteristics of the skin and dictate the unique skin care requirements. This study aimed to identify the likely biomarkers and molecular signatures expressed in skin cells of different ethnic backgrounds, which could aid further the design of personalized skin products based on specific demands.

Methods

Using data mining and in-silico modeling, the association of SNP-affected genes with three major skin types of European, Asian and African origin was analyzed and compared within the structure-function gene interaction networks. Cultured dermal fibroblasts were subsequently subjected to ultraviolet radiation and oxidative stress and analyzed for DNA damage and senescent markers. The protective applications of two cosmetic ingredients, Resveratrol and Quercetin, were validated in both cellular and in-silico models.

Results

Each skin type was characterized by the presence of SNPs in the genes controlling facultative and constitutive pigmentation, which could also underlie the major differences in responses to photodamage, such as oxidative stress, inflammation, and barrier homeostasis. Skin-type-specific dermal fibroblasts cultured in-vitro demonstrated distinctive sensitivities to ultraviolet radiation and oxidative stress, which could be modulated further by the bioactive compounds with the predicted capacities to interact with some of the genes in the in-silico models.

Conclusion

Evaluation of the SNP-affected gene networks and likely sensitivities of skin cells, defined as low threshold levels to extrinsic stress factors, can provide a valuable tool for the design and formulation of personalized skin products that match more accurately diverse ethnic backgrounds.

A systematic review of skin ageing genes: gene pleiotropy and genes on the chromosomal band 16q24.3 may drive skin ageing

Skin ageing is the result of intrinsic genetic and extrinsic lifestyle factors. However, there is no consensus on skin ageing phenotypes and ways to quantify them. In this systematic review, we first carefully identified 56 skin ageing phenotypes from multiple literature sources and sought the best photo-numeric grading scales to evaluate them. Next, we conducted a systematic review on all 44 Genome-wide Association Studies (GWAS) on skin ageing published to date and identified genetic risk factors (2349 SNPs and 366 genes) associated with skin ageing. We identified 19 promising SNPs found to be significantly (p-Value < 1E-05) associated with skin ageing phenotypes in two or more independent studies. Here we show, using enrichment analyses strategies and gene expression data, that (1) pleiotropy is a recurring theme among skin ageing genes, (2) SNPs associated with skin ageing phenotypes are mostly located in a small handful of 44 pleiotropic and hub genes (mostly on the chromosome band 16q24.3) and 32 skin colour genes. Since numerous genes on the chromosome band 16q24.3 and skin colour genes show pleiotropy, we propose that (1) genes traditionally identified to contribute to skin colour have more than just skin pigmentation roles, and (2) further progress towards understand the development of skin pigmentation requires understanding the contributions of genes on the chromosomal band 16q24.3. We anticipate our systematic review to serve as a hub to locate primary literature sources pertaining to the genetics of skin ageing and to be a starting point for more sophisticated work examining pleiotropic genes, hub genes, and skin ageing phenotypes.

"Normal" TEWL-How Can it be Defined?: A Systematic Review

BACKGROUND

Transepidermal water loss (TEWL), the total non-eccrine sweat water evaporating from a given area of epidermis over time, is a measurement of skin barrier integrity. Skin diseases (e.g. psoriasis and atopic dermatitis) often result in transient increases in TEWL, so knowledge of "normal" TEWL values may be used to predict disease progression in dermatological settings. Variables such as age, race, and anatomic location have been suggested to affect TEWL, but current regulatory agencies have failed to control for additional variables of interest. Thus, this review summarizes variables that may cause TEWL variation.

METHODS

A comprehensive literature search was performed using Embase, PubMed, and Web of Science to find human studies that provided data on variables affecting TEWL.

RESULTS

31 studies, analyzing 22 affecting TEWL, were identified. Variables causing increased TEWL were mask-use (n=1), Dry Eye Disease (n=1), Chronic Venous Disease (n=1), Coronary Artery Disease (n=1), age (infants vs. adults) (n=4), nourishment in infants (n=1), stress within individuals (n=2), Body Mass Index (n=2), bathing versus showering (n=2), and scratching/friction (n=1). Variables with decreases in TEWL were genetic variability with SNPs on chromosome 9q34.3 (n=1) and cancer-cachexia (n=1).

CONCLUSION

We summarized 12 variables that impact TEWL and are not typically controlled for in experimental settings. Therefore, defining normal TEWL may currently be problematic. Thus, regulatory agencies should provide stricter guidelines on proper measurement of TEWL to minimize human introduced TEWL variation, and we should continue to examine factors impacting individual skin integrity.

Genome-wide association studies in Japanese women identified genetic loci associated with wrinkles and sagging

Wrinkles and sagging are caused by various factors, such as ultraviolet rays; however, recent findings demonstrated that some individuals are genetically predisposed to these phenotypes of skin aging. The contribution of single nucleotide polymorphisms (SNPs) to the development of wrinkles and sagging has been demonstrated in genome-wide association studies (GWAS). However, these findings were mainly obtained from European and Chinese populations. Limited information is currently available on the involvement of SNPs in the development of wrinkles and sagging in a Japanese population. Therefore, we herein performed GWAS on wrinkles at the outer corners of the eyes and nasolabial folds in 1041 Japanese women. The results obtained revealed that 5 SNPs (19p13.2: rs2303098 (p = 3.39×10^-8 ), rs56391955 (p = 3.39×10^-8 ), rs67560822 (p = 3.50×10^-8 ), rs889126 (p = 3.78×10^-8 ), rs57490083 (p = 3.99×10^-8 )) located within the COL5A3 gene associated with wrinkles at the outer corners of the eyes. Regarding nasolabial folds, 8q24.11 (rs4876369; p = 1.05×10^-7 , rs6980503; p = 1.25×10^-7 , rs61027543; p = 1.25×10^-7 , rs16889363; p = 1.38×10^-7 ) was suggested to be associated with RAD21 gene expression. These SNPs have not been reported in other populations, and were first found in Japanese women population. These SNPs may be used as markers to examine the genetic predisposition of individuals to wrinkles and sagging.

Search for genetic loci involved in the constitution and skin type of a Japanese women using a genome-wide association study

The constitution and skin type of individuals are influenced by various factors. Recently, the influence of genetic predispositions on these has been emphasized. To date, genome-wide association studies (GWAS) have shown several single nucleotide polymorphisms (SNPs) that affect individual's constitution and skin type. However, these studies have mainly focused on the Caucasian population, and only a few association analyses with the constitution and skin type of individuals involving a Japanese population have been conducted. In this study, we conducted a GWAS analysis of 9 phenotypes regarding the constitution or skin type of 1108 Japanese women based on a questionnaire. As a result, in addition to SNPs known to be involved in phenotypes in the past, we discovered new SNPs and genetic regions related to darkness of pigmented spots, skin flushing, frequency of rough skin and responsiveness to cosmetics.

A DNA-Based Intelligent Expert System for Personalised Skin-Health Recommendations

Intensive attention on personalised skin-health solutions is on account of incomparable love of skin and an urgent need for effective treatment. In the meanwhile, people have great expectations on how to utilise genetic knowledge of our body to provide a precise solution for different individuals, such as daily use of skin-health products, since the rapid development of genetic test services and skin-health science. However, the complexity of multi-modal data, the establishment of correlations between consumer genetic data and product ingredients are the main obstacles encountered today. Determining to settle such obstacles, a personalised recommendation expert system for selecting optimised skin-health product within the category based upon genetic phenotypes for each consumer was introduced in this article. Random Forests were implemented to achieve automatic product categorisation, the performance discussed and compared with SVM and Logistic Regression. Lastly, categorised skin-health product suggestion was made with an optimised recommendation model based on associated genetic phenotype information. Potential changes (up to 71.0% more phenotypic relevant ingredients) from experiments using real product data were demonstrated and compared with imitated cases of real-life human selections.