Gene variants associated with acne vulgaris presentation and severity: a systematic review and meta-analysis

Integrative bioinformatics and experimental validation of hub genetic markers in acne vulgaris: Toward personalized diagnostic and therapeutic strategies

BACKGROUND

Acne vulgaris is a widespread chronic inflammatory dermatological condition. The precise molecular and genetic mechanisms of its pathogenesis remain incompletely understood. This research synthesizes existing databases, targeting a comprehensive exploration of core genetic markers.

METHODS

Gene expression datasets (GSE6475, GSE108110, and GSE53795) were retrieved from the GEO. Differentially expressed genes (DEGs) were identified using the limma package. Enrichment analyses were conducted using GSVA for pathway assessment and clusterProfiler for GO and KEGG analyses. PPI networks and immune cell infiltration were analyzed using the STRING database and ssGSEA, respectively. We investigated the correlation between hub gene biomarkers and immune cell infiltration using Spearman's rank analysis. ROC curve analysis validated the hub genes' diagnostic accuracy. miRNet, TarBase v8.0, and ChEA3 identified miRNA/transcription factor-gene interactions, while DrugBank delineated drug-gene interactions. Experiments utilized HaCaT cells stimulated with Propionibacterium acnes, treated with retinoic acid and methotrexate, and evaluated using RT-qPCR, ELISA, western blot, lentiviral transduction, CCK-8, wound-healing, and transwell assays.

RESULTS

There were 104 genes with consistent differences across the three datasets of paired acne and normal skin. Functional analyses emphasized the significant enrichment of these DEGs in immune-related pathways. PPI network analysis pinpointed hub genes PTPRC, CXCL8, ITGB2, and MMP9 as central players in acne pathogenesis. Elevated levels of specific immune cell infiltration in acne lesions corroborated the inflammatory nature of the disease. ROC curve analysis identified the acne diagnostic potential of four hub genes. Key miRNAs, particularly hsa-mir-124-3p, and central transcription factors like TFEC were noted as significant regulators. In vitro validation using HaCaT cells confirmed the upregulation of hub genes following Propionibacterium acnes exposure, while CXCL8 knockdown reduced pro-inflammatory cytokines, cell proliferation, and migration. DrugBank insights led to the exploration of retinoic acid and methotrexate, both of which mitigated gene expression upsurge and inflammatory mediator secretion.

CONCLUSION

This comprehensive study elucidated pivotal genes associated with acne pathogenesis, notably PTPRC, CXCL8, ITGB2, and MMP9. The findings underscore potential biomarkers, therapeutic targets, and the therapeutic potential of agents like retinoic acid and methotrexate. The congruence between bioinformatics and experimental validations suggests promising avenues for personalized acne treatments.

Identification of differentially methylated genes for severe acne by genome-wide DNA methylation and gene expression analysis

Severe acne is a chronic inflammatory skin condition that is affected by both genetic and environmental factors. DNA methylation is associated with a variety of inflammatory skin diseases, but its role in severe acne is unclear. In this study, we conducted a two-stage epigenome correlation study using 88 blood samples to identify disease-related differential methylation sites. We found close associations between the DNA methylation at 23 differentially methylated sites (DMSs) and severe acne, including PDGFD, ARHGEF10, etc. Further analysis revealed that differentially methylated genes (PARP8 and MAPKAPK2) were also expressed differently between severe acne and health control groups. These findings lead us to speculation that epigenetic mechanisms may play an important role in the pathogenesis of severe acne.

Effect of interleukin-12 gene expression on insulin resistance in patients with acne vulgaris

BACKGROUND

Insulin resistance (IR) is a condition where cells become resistant to insulin, causing impaired glucose uptake and increased blood glucose levels. Interleukin-12 (IL-12), a cytokine, regulates the immune system. High levels of IL-12 can lead to chronic inflammation, exacerbate resistance to insulin, and contribute to type 2 diabetes. Also, link IR to acne vulgaris (AV), as it reduces tissue sensitivity to insulin, causing increased insulin levels and sebum production, which can contribute to acne development.

AIM

To explore the role of IL-12 gene expression on IR in AV patients and to study the role of IL-12 gene in the development of AV.

SUBJECTS AND METHODS

A case-control study was performed on 68 AV patients and 68 healthy controls. The biochemical analysis included fasting glucose, fasting insulin, (HOMA-IR), and serum IL-12 level. IL-12 gene expression was performed by quantitative real-time PCR for both two groups. In addition, folding change was calculated by using the standard 2-(∆∆Ct) method.

RESULT

IL-12 level, IL-12 folding change, fasting insulin, and IR were all increased in acne patients. A highly significant linear correlation was found between IL-12 folding change and both IL-12 levels and IR. There is a substantial positive significant simple linear association between IL-12 level and IL-12 folding change, as well as IR and IL-12 folding change, in moderate and severe acne.

CONCLUSION

IL-12 gene has an important role in IR and the development of acne in AV patients.

Genetic Variants Associated with Acne Vulgaris

Acne vulgaris (AV) ranks among the common chronic inflammatory disorders that impact the sebaceous components of hair follicles. Acne vulgaris is characterised by cardinal manifestations such as the presence of pimples, nodules, pustules, and cysts, which have the potential to lead to the development of acne scarring and pigmentation. The phenomenon is influenced by polygenic inheritance or can be ascribed to the interplay between multiple genes and environmental factors. In recent years, some researchers have found that some genes (such as IL, TNF, RETN, CYP family, MMPs and TIMPs genes et al) are associated with acne vulgaris and may affect the progression and prognosis of the disease. The number of reviews addressing acne-associated genetic variants, however, is limited. In that case, we have compiled a list of prevalent genes associated with acne in recent times. This helps us understand acne's genetic basis and lets us step in early for people prone to severe acne, lowering the chance of acne scars.

Knowledge, attitudes, and practices of community pharmacists toward the management of acne vulgaris in Saudi Arabia

Background and objectives

In Saudi Arabia, Acne vulgaris is a very predominant ailment and Pharmacists currently have standardized protocols at their disposal for the treatment of acne. Pharmacists often prescribe medications for minor cases of acne. Therefore, this study aimed to explore community pharmacists (CPs)' knowledge, attitudes, and practice toward acne management in Riyadh, Saudi Arabia.

Methods

An online cross-sectional study was conducted among CPs working in Riyadh, Saudi Arabia from January and April 2021, using a self-administered, questionnaire, was divided into four sections that collected information from the CP's Knowledge, attitudes, and practices and the management of acne vulgaris. The data were analyzed using the Statistical Package for the Social Sciences version 26 (SPSS).

Result

A total of 313 CPs were enrolled in the study who successfully returned the questionnaire. The mean score of knowledge on etiology, pathophysiology, and therapy for AV was 5.3 ± (SD = 1.5). However, the majority of CPs had a moderate level of knowledge (80.8%), followed by mild to moderate (12.8%). This study showed that CPs had an insufficient level of knowledge about ace management, about 6% of CPs have a high level of knowledge. Inadequate knowledge was revealed in their management practice, only 0.3% of CPs treated patients with acne on their own without a referral. In addition, CPs showed a positive attitude toward acne management.

Conclusion

There is a need to improve CPs' understanding of acne care and to contribute to participating in organized training sessions on the management of AV.

Sun exposure, a relevant exposome factor in acne patients and how photoprotection can improve outcomes

BACKGROUND

Acne pathophysiology includes a complex interaction among inflammatory mediators, hyperseborrhea, alteration of keratinization and follicular colonization by Propionibacterium acnes.

AIMS

To describe the impact of the exposome on acne and how photoprotection can improve outcomes.

METHODS

A narrative review of the literature was carried out; searches with Google Scholar and Pubmed from January 1992 to November 2022 were performed. The keywords used were "acne," "sunscreens," "photoprotection," "cosmetics," "cosmeceuticals," "pathogenesis," "etiology," "exposome," "sunlight," "stress," "lack of sleep," "diet," "postinflammatory hyperpigmentation," "pollution," "exposome," "ultraviolet radiation," and "visible light."

RESULTS

Environmental factors such as solar radiation, air pollution, tobacco consumption, psychological stress, diverse microorganisms, nutrition, among others, can trigger or worsen acne. Solar radiation can temporarily improve lesions. However, it can induce proinflammatory and profibrotic responses, and produce post-inflammatory hyperpigmentation and/or post-inflammatory erythema. While photoprotection is widely recommended to acne patients, only four relevant studies were found. Sunscreens can significantly improve symptomatology or enhance treatment and can prevent post-inflammatory hyperpigmentation. Furthermore, they can provide camouflage and improve quality of life. Based on acne pathogenesis, optimal sunscreens should have emollient, antioxidant and sebum controlling properties.

CONCLUSIONS

The exposome and solar radiation can trigger or worsen acne. UV light can induce post-inflammatory hyperpigmentation/erythema, and can initiate flares. The use of specifically formulated sunscreens could enhance adherence to topical or systemic therapy, camouflage lesions (tinted sunscreens), decrease inflammation, and reduce the incidence of post-inflammatory hyperpigmentation/erythema.

Metabolic and Dietary Factors in Acne Vulgaris and Evaluation of the Acne Vulgaris Treatment with Oral Contraceptive-Based Therapies in Young Adult Women

The etiopathogenesis of acne is complex, as several endo- and exogenous factors that affect the sebaceous-hair unit are involved in the development of acne lesions. The main aim of the study was to evaluate selected metabolic parameters before treatment. Another goal of the study was to determine the correlation between selected metabolic and dietary parameters and the severity of acne before treatment. The third objective was to assess the severity of acne before and after treatment, considering the type of treatment used. The final objective was to assess the relationship between the difference in acne severity before and after treatment, considering the type of treatment used and factors of dairy or sweets intake. 168 women participated in the study. The patients belonged to two groups: the study group (99 patients with acne vulgaris) and the control group (69 patients without skin lesions). The study group was divided into subgroups according to the treatment used: contraceptive preparation, contraceptive preparation and cyproterone acetate, and contraceptive preparation and isotretinoin preparation. We found that LDL levels and consumption of sweets correlated with acne severity. The mainstay of acne treatment is contraceptive treatment (ethinylestradiol and drospirenone). The effectiveness of the three contraceptive-based treatments was confirmed by observing the severity of acne. There were no significant correlations between the difference in acne severity before and after treatment with the three treatments and factors of dairy or sweet consumption.

Genome-wide meta-analysis identifies novel loci conferring risk of acne vulgaris

Acne vulgaris is a common chronic skin disorder presenting with comedones, cystic structures forming within the distal hair follicle, and in most cases additionally with inflammatory skin lesions on the face and upper torso. We performed a genome-wide association study and meta-analysis of data from 34,422 individuals with acne and 364,991 controls from three independent European-ancestry cohorts. We replicated 19 previously implicated genome-wide significant risk loci and identified four novel loci [11q12.2 (FADS2), 12q21.1 (LGR5), 17q25.3 (FASN), and 22q12.1 (ZNRF3-KREMEN1)], bringing the total number of reported acne risk loci to 50. Our meta-analysis results explain 9.4% of the phenotypic variance of acne. A polygenic model of acne risk variants showed that individuals in the top 5% of the risk percentiles had a 1.62-fold (95% CI 1.47-1.78) increased acne risk relative to individuals with average risk (20-80% on the polygenic risk score distribution). Our findings highlight the Wnt and MAPK pathways as key factors in the genetic predisposition to acne vulgaris, together with the effects of genetic variation on the structure and maintenance of the hair follicle and pilosebaceous unit. Two novel loci, 11q12.2 and 17q25.3, contain genes encoding key enzymes involved in lipid biosynthesis pathways.

Acne Vulgaris Relapse in Sudanese Patients Treated with Oral Isotretinoin: Rate and Predictive Factors

Purpose

Acne vulgaris is a skin disorder primarily affecting teenagers and young adults. Acne relapse is the main drawback of oral isotretinoin (OI), which is the golden therapy for severe acne. This study aimed to assess the rate and predictive factors of acne relapse among Sudanese patients using OI.

Patients and Methods

A cross-sectional study was conducted in a dermatology and venereology clinic-Sudan, using a self-administered questionnaire and data collection sheet. Patients using OI for acne treatment were enrolled in the study. Chi-square test and logistic regression analysis were used to evaluate the association between variables. P-value <0.05 was considered statistically significant.

Results

225 acne patients (mean age: 26.0±4.2 years, females: 88.9%) were included in this study. OI daily dose ranged from 0.25 to 1 mg/kg/day, with frequent daily doses of 40-49 mg (57.3%) over 3-6 months (81.8%). Around one-third of patients (36%) received maintenance therapy after completion of OI course. At a 2-year follow-up, approximately 36% of patients experienced acne relapse that commonly occurred within 6-18 months after the last OI therapy. Early discontinuation of OI was a positive predictor of acne relapse which was 3.99 times greater in patients who had early discontinued OI than those completing the planned OI course (OR=3.99; p=0.002). OI cumulative doses of 120-139 mg/kg and 140-159 mg/kg were negative predictors of acne relapse (OR=0.23; p=0.001 and OR=0.15; p=0.02, respectively). Most patients (94.2%) received prescription OI, and 76.4% of women were advised to use contraceptives. About 69% of patients practiced skin care.

Conclusion

About one-third of patients experienced acne relapse. Early discontinuation and low cumulative doses of OI are the main risk factors for acne relapse. Long-term therapy of OI, with cumulative doses of 120-159 mg/kg, would be beneficial to reduce acne relapse.

Cannabinoid Compounds as a Pharmacotherapeutic Option for the Treatment of Non-Cancer Skin Diseases

The endocannabinoid system has been shown to be involved in various skin functions, such as melanogenesis and the maintenance of redox balance in skin cells exposed to UV radiation, as well as barrier functions, sebaceous gland activity, wound healing and the skin's immune response. In addition to the potential use of cannabinoids in the treatment and prevention of skin cancer, cannabinoid compounds and derivatives are of interest as potential systemic and topical applications for the treatment of various inflammatory, fibrotic and pruritic skin conditions. In this context, cannabinoid compounds have been successfully tested as a therapeutic option for the treatment of androgenetic alopecia, atopic and seborrhoeic dermatitis, dermatomyositis, asteatotic and atopic eczema, uraemic pruritis, scalp psoriasis, systemic sclerosis and venous leg ulcers. This review provides an insight into the current literature on cannabinoid compounds as potential medicines for the treatment of skin diseases.

Network Pharmacology-Based Investigation on the Mechanism of the JinGuanLan Formula in Treating Acne Vulgaris

Background

JinGuanLan (JGL) formula is a traditional Chinese medicine (TCM) developed by the Department of Pharmacology at the First Hospital of Lanzhou University. The network pharmacology approach was applied to determine the potential active compounds, therapeutic targets, and main pathways of the JGL formula to evaluate its application value in acne vulgaris.

Methods

Data on the active compounds and their related targets were obtained from the Traditional Chinese Medicine Systems Pharmacology Database and Analysis Platform (TCMSP). Acne vulgaris-related targets were searched from the Online Mendelian Inheritance in Man (OMIM) database, GeneCards Database, Comparative Toxicogenomics Database (CTD), Therapeutic Target Database (TTD), and DisGeNET Database. Targets intersecting between JGL- and acne vulgaris-related targets were chosen as potential therapeutic targets. The protein-protein interaction (PPI) network of potential therapeutic targets was visualized using Cytoscape software based on the PPI data collected from the STRING database. Three topological features, namely, "Degree," "MCC," and "EPC" of each node in the PPI network were calculated using the cytoHubba plugin of Cytoscape to excavate the core targets. R program was used for the Gene Ontology (GO) and Kyoto Encyclopedia of Genes and Genomes (KEGG) enrichment analysis of the potential therapeutic targets. Finally, the compound-target-pathway network was constructed.

Result

Among the 148 active compounds that were identified, quercetin and kaempferol showed the highest degree of target interaction and thus may play essential roles in the pharmacological effect of the JGL formula for acne treatment. Among the 97 potential therapeutic targets that were screened out, the 6 core targets were TNF, JUN, IL6, STAT3, MAPK1, and MAPK3. A total of 2260 terms of GO enrichment analysis were obtained, including 2090 for biological processes (BP), 37 for cellular components (CC), and 133 for molecular function (MF). A total of 156 enriched KEGG pathways were identified, including TNF, IL-17, Th17 cell differentiation, MAPK, PI3K-Akt, T cell receptor, and Toll-like receptor signalling pathways.

Conclusion

This work showed that the JGL formula might reverse the pathological changes associated with acne vulgaris through its antiinflammatory effect and regulate the excessive lipogenesis in sebaceous glands via different signalling pathways. This new drug has application value and is worthy of further research and development.

Golgin A7 Family Member B (GOLGA7B) is a plausible novel gene associating high glycaemic index diet with acne vulgaris

While the IGF1/FoxO1/mTORC1 signalling pathway is a well-established nutrigenomic link between high glycaemic index (GI)/glycaemic load (GL) diet and acne vulgaris, other signalling pathways remain elusive. Therefore, we aimed to investigate other genes that are involved in the high GI/GL diet-acne link, using our Singapore/Malaysia population epidemiological, genomics and transcriptomics data. High GI/GL dietary habit of 3,207 acne cases (1,869 and 1,341 further classified into severity and scarring grades, respectively) and 2,521 controls were evaluated based on Quality of Diet based on Glycaemic Index Score (QDGIS). Overlapping concordant differentially expressed genes (DEGs) between acne case-controls and QDGIS poor-moderate/good classes were identified from whole-transcriptome sequencing data of PBMC of a subset of participants. Finally, we assessed the expression quantitative trait loci (eQTL) association of single nucleotide polymorphisms (SNPs) of the concordant DEGs. Daily intake of fruits significantly reduced the risk of acne presentation, severity and scarring by up to 48.5%. Those with good QDGIS had significantly lower risk of mild and moderate/severe acne, and grade 1/2 acne scarring. Sequential filtering identified four overlapping concordant DEGs that were significantly associated with acne and QDGIS, namely GOLGA7B, SNCB, LOC102723849 and LOC283683. Combining transcriptome and genetic association data, we identified intronic SNP rs1953947 in GOLGA7B as an eQTL for acne. In conclusion, we identified GOLGA7B as a plausible novel gene that links high GI/GL with acne, and hence propose a model for the involvement of Golga7b in high GI/GL diet-acne pathogenesis, which includes palmitoyl acyltransferase zDHHC5, fatty acid translocase CD36 and palmitic acid.

The Role of Skin Immune System in Acne

Acne vulgaris is a skin disease that often occurs in adolescence and in young adulthood. The main pathogenic factors are hyperkeratinization, obstruction of sebaceous glands, stimulation of sebaceous gland secretion by androgens, and bacterial colonization of sebaceous units by Cutibacterium acnes, which promotes inflammation. Little is known about the role of skin immune cells in the development of acne lesions. The aim of the study was to try to understand the role of skin immune cells in the course of acne. Recent studies have shown that there are at least four major pathways by which Cutibacterium acnes interacts with the innate immune system to induce inflammation: through TLRs, activating inflammasomes, inducing the production of matrix metalloproteinases (MMPs), and stimulating antimicrobial peptide (AMP) activity. Cells of adaptive immune response, mainly Th1 and Th17 lymphocytes, also play an important role in the pathogenesis of acne. It is worth emphasizing that understanding the role of the skin’s immune cells in the pathogenesis of acne may, in the future, contribute to the application of modern therapeutic strategies that would avoid addiction to antibiotics, which would alleviate the spectrum of resistance that is now evident and a current threat.

TIMP2 genetic variation rs4789932 may associate with an increased risk of developing acne scarring based on a case-control study of Chinese Han population

BACKGROUND

Acne vulgaris is a common chronic inflammatory cutaneous disorder that has a higher prevalence in adolescents and young adults. Previous studies have indicated that both genetic and environmental factors contribute to its risk. The protein encoded by the TIMP2 gene is a natural inhibitor of matrix metalloproteinases (MMPs). Changes in TIMP2 expression are speculated to disrupt the TIMP/MMP balance and result in acne scarring.

AIMS

Our study aimed to comprehensively explore the potential genetic susceptibility of TIMP2 to acne scarring based on a case-control study.

PATIENTS AND METHODS

In total, 1060 patients with acne scarring (cases) and 2162 patients without acne scarring (controls) were enrolled in the present study. Seventeen tag single-nucleotide polymorphisms (SNPs) in the TIMP2 gene were selected for genotyping. Genetic association analyses were conducted at both the single marker and haplotypic levels. Single marker-based association analyses were performed in the genotypic model and allelic model. The distributions of clinical variables in different genotype groups of targeted SNPs in patients with acne scarring were also examined.

RESULTS

SNP rs4789932 was identified to be significantly associated with the risk of acne scarring in both the genotypic model (p = 0.001) and allelic model (p = 0.0002). The C allele of SNP rs4789932 was significantly associated with an increased risk of acne scarring (OR [95% CI] = 1.23 [1.10-1.37]). Significant differences were identified between the SNP rs4789932 genotypes and the clinical severity of acne scarring (p < 2.2 × 10^-16 ). The C allele of SNP rs4789932 was associated with severe clinical features of acne scarring.

CONCLUSIONS

A significant genetic marker of the promoter region in TIMP2 was identified to contribute to the risk of acne scarring in the Chinese Han population and was significantly associated with the clinical severity of acne scarring in patients.

Magnitude and temporal trend of acne vulgaris burden in 204 countries and territories from 1990 to 2019: A analysis from the Global Burden of Disease Study 2019

BACKGROUND

Acne vulgaris is widespread across the world. Mapping the latest magnitudes and temporal trends of acne vulgaris provides the essential foundation for targeted public policies at the national, regional, and global levels.

METHODS

Complying with the framework of the Global Burden of Disease 2019 Study, the incidence, prevalence and disability-adjusted life years (DALYs) on acne vulgaris were retrieved in 204 countries and regions from 1990 to 2019. The average annual percentage change was calculated to depict the temporal trends in age-standardized rates (ASRs) of acne vulgaris burden by region, sex, and age.

RESULTS

Globally, 117.4 [95% uncertainty interval (UI): 103.0, 133.7] million incident cases of acne vulgaris, 231.2 million (95% UI: 208.2, 255.5) prevalent cases and 5.0 (95% UI: 3.0, 7.9) million DALYs were estimated in 2019, with about 47% increase compared with 1990. Moreover, the overall ASRs of acne vulgaris increased by around 0.55% annually over the past three decades. We observed huge disparities in ASRs of acne vulgaris with its changing trends in sex, location, and age. The ASR of acne vulgaris among women was around 1.3 times that of men, but the gender difference was narrowed for the pronounced increase among men. The ASRs of acne vulgaris were higher in high-income regions, but the increasing trend was more pronounced in other regions.

CONCLUSION

The burden rate of acne vulgaris continues to increase in almost all countries. Understanding the specific characteristics of acne vulgaris burden is essential to formulate more effective and targeted interventions for controlling acne burden.