Screening mitochondria-related biomarkers in skin and plasma of atopic dermatitis patients by bioinformatics analysis and machine learning.

Background: There is a significant imbalance of mitochondrial activity and oxidative stress (OS) status in patients with atopic dermatitis (AD). This study aims to screen skin and peripheral mitochondria-related biomarkers, providing insights into the underlying mechanisms of mitochondrial dysfunction in AD. Methods: Public data were obtained from MitoCarta 3.0 and GEO database. We screened mitochondria-related differentially expressed genes (MitoDEGs) using R language and then performed GO and KEGG pathway analysis on MitoDEGs. PPI and machine learning algorithms were also used to select hub MitoDEGs. Meanwhile, the expression of hub MitoDEGs in clinical samples were verified. Using ROC curve analysis, the diagnostic performance of risk model constructed from these hub MitoDEGs was evaluated in the training and validation sets. Further computer-aided algorithm analyses included gene set enrichment analysis (GSEA), immune infiltration and mitochondrial metabolism, centered on these hub MitoDEGs. We also used real-time PCR and Spearman method to evaluate the relationship between plasma circulating cell-free mitochondrial DNA (ccf-mtDNA) levels and disease severity in AD patients. Results: MitoDEGs in AD were significantly enriched in pathways involved in mitochondrial respiration, mitochondrial metabolism, and mitochondrial membrane transport. Four hub genes (BAX, IDH3A, MRPS6, and GPT2) were selected to take part in the creation of a novel mitochondrial-based risk model for AD prediction. The risk score demonstrated excellent diagnostic performance in both the training cohort (AUC = 1.000) and the validation cohort (AUC = 0.810). Four hub MitoDEGs were also clearly associated with the innate immune cells' infiltration and the molecular modifications of mitochondrial hypermetabolism in AD. We further discovered that AD patients had considerably greater plasma ccf-mtDNA levels than controls (U = 92.0, p< 0.001). Besides, there was a significant relationship between the up-regulation of plasma mtDNA and the severity of AD symptoms. Conclusions: The study highlights BAX, IDH3A, MRPS6 and GPT2 as crucial MitoDEGs and demonstrates their efficiency in identifying AD. Moderate to severe AD is associated with increased markers of mitochondrial damage and cellular stress (ccf=mtDNA). Our study provides data support for the variation in mitochondria-related functional characteristics of AD patients.

Causal effects of fatty acids on atopic dermatitis: A Mendelian randomization study.

Background: Some evidence suggests abnormalities in fatty acids in patients with atopic dermatitis (AD), and benefits of supplementation with these fatty acids have been reported. However, there is still substantial controversy on the correlation between fatty acids and AD. Therefore, the aim of this study was to determine whether fatty acid levels are causally related to AD using a Mendelian randomization approach. Methods: We evaluated the data about the fatty acids levels and AD with various methods from Genome-Wide Association Study (GWAS). GWAS results were available both from European ancestry. Mendelian randomization methods were used to analysis the casual inference of fatty acids on AD. MR Egger and MR-PRESSO were used to determine pleiotropy and heterogeneity. Further analysis was conducted using instruments associated with the FADS genes to address mechanisms involved. We also used Multivariate MR (MVMR) to show the independent casual inference of omega-3 (n-3) fatty acids on AD. Results: Mendelian randomization (MR) analysis suggests that n-3 fatty acid levels are associated with a lower risk of AD (n-3 ORIVW: 0.92, 95% confidence interval [CI]: 0.87-0.98; p = 0.01). Moreover, docosahexaenoic acids (DHA) levels, which is a kind of long-chain, highly unsaturated omega-3 (n-3) fatty acid, and its higher level was associated with a lower risk of AD (DHA ORIVW: 0.91, 95% CI: 0.84-0.98; p = 0.02). We ran multivariable MR analysis while controlling for variables within the other types of fatty acids. The effect estimates agreed with the preliminary MR analysis indicating the effect of n-3 fatty acids levels on AD was robust. MR-egger suggest no significant pleiotropy and heterogeneity on genetic instrumental variants. Outliers-corrected MR analyses after controlling horizontal pleiotropy were still robust. The single-SNP analyses revealed that n-3 fatty acids are likely linked to a decreased risk of AD through FADS cluster, highlighting the significance of the FADS gene in the fatty acids synthesis pathway in the development of AD. Conclusion: Our studies suggest that n-3 fatty acids may reduce the risk of AD. Risk prediction tools based on n-3 fatty acid levels may be valuable methods for improving AD screening and primary prevention. To reduce the risk of AD, individuals could enhance n-3 fatty acids intake through supplement or diet.

Epidemiology of urticaria in China: a population-based study.

BACKGROUND: Urticaria is a common skin disease characterized by episodes of wheals, and it has a negative effect on patients' quality of life. Large-scale population-based epidemiological studies of urticaria are scarce in China. The aim of this survey was to determine the prevalence, clinical forms, and risk factors of urticaria in the Chinese population. METHODS: This survey was conducted in 35 cities from 31 provinces, autonomous regions, and municipalities of China. Two to three communities in each city were selected in this investigation. Participants completed questionnaires and received dermatological examinations. We analyzed the prevalence, clinical forms, and risk factors of urticaria. RESULTS: In total, 44,875 questionnaires were distributed and 41,041 valid questionnaires were collected (17,563 male and 23,478 female participants). The lifetime prevalence of urticaria was 7.30%, with 8.26% in female and 6.34% in male individuals ( P  < 0.05). The point prevalence of urticaria was 0.75%, with 0.79% in female and 0.71% in male individuals ( P  < 0.05). Concomitant angioedema was found in 6.16% of patients. Adults had a higher prevalence of urticaria than adolescents and children. Living in urban areas, exposure to pollutants, an anxious or depressed psychological status, a personal and family history of allergy, thyroid diseases, and Helicobacter pylori infection were associated with a higher prevalence of urticaria. Smoking was correlated with a reduced risk of urticaria. CONCLUSION: This study demonstrated that the lifetime prevalence of urticaria was 7.30% and the point prevalence was 0.75% in the Chinese population; women had a higher prevalence of urticaria than men. Various factors were correlated with urticaria.

Role of MMP-2(-1306 C/T) and TIMP-2(-418G/C) Polymorphism in Chinese Han Patients with Acne Vulgaris.

Acne is the most common chronic inflammatory skin diseases. Multiple factors, such as hormonal, environmental, immunological, and genetic factors, are thought to be involved in acne. However, genetic studies have yet to elucidate the full mechanism of acne. The aim of this study was to investigate the association of MMP-2 (-1306C/T) and TIMP-2 (-418G/C) polymorphisms with the risk of acne vulgaris in a Chinese Han population. We also analyzed the correlation of clinical parameters and family history in patients with acne vulgaris. This study included 251 acne patients and 121 age- and sex-matched healthy controls. Genomic DNA was extracted from peripheral blood, and genotyping was performed by PCR and DNA sequencing techniques. There is a significant correlation between the MMP-2 (-1306C/T) polymorphism and the acne vulgaris (P<0.001). Although no association was found between the TIMP-2 (-418G/C) polymorphism and the acne vulgaris, patients with the MMP-2 CT/TIMP-2 GG or GC allele are at higher risk of acne vulgaris. There is also a significant difference in the severity of the disease between acne vulgaris patients with and without family history (P<0.001). This study indicated that the MMP-2 (-1306C/T) polymorphism, in combination with the TIMP-2 (-418G/C) polymorphism, contributes to acne vulgaris susceptibility in the Chinese Han population.

Comprehensive survey of vitiligo patients in the northeast of China using a predesigned questionnaire.

To assess the sociodemographic data and clinical information of outpatients affected by vitiligo in the northeast of China, vitiligo patients or guardians who presented to the clinic were invited to participate in an exploratory questionnaire. The questionnaire consisted of two sections related to vitiligo, including sociodemographic data and clinical information. A total of 983 vitiligo patients answered the questionnaire. The rates of female and male patients were comparable. The investigated patients were mostly young and middle-aged. Most patients suffered from vitiligo in childhood or young adulthood. Vitiligo vulgaris was the most common type of vitiligo in clinic and 53.0% of patients were categorized as body surface area (BSA) of 10% or less. In response to the latest treatment, 43.6% of patients achieved good response (completely stopped or almost disappeared). More patients at active stage showed good response than the patients at stable stage (χ2 = 7.866, P < 0.05). Chronic comorbid condition(s) were observed in 12.6% of patients with BSA of more than 10%, whereas those were seen in 6.0% of patients with BSA of 10% or less (χ2 = 12.969, P < 0.05). In conclusion, active vitiligo seems to respond better than stable vitiligo and complications with other autoimmune diseases more frequently observed in severe patients than mild patients. The current study presented a comprehensive understanding of vitiligo in the northeast of China.

Role of the complement anaphylatoxin C5a-receptor pathway in atopic dermatitis in mice.

Atopic dermatitis (AD) is a chronic inflammatory skin disease with a genetic background. The C5a­receptor (C5aR) pathway has been reported to be involved in AD; however, the precise pathogenesis remains to be elucidated. In the present study, the contribution of the C5aR pathway to AD in mice was investigated. A BALB/c mouse model of AD was induced by application of 2,4­dinitrochlorobenzene (DNCB) onto hairless dorsal skin. Following DNCB application for 2 weeks, C5aR expression in skin tissue was assessed by reverse transcription quantitative polymerase chain reaction. C5aR expression in skin tissue was significantly increased in mice with AD. In an additional experiment, C5aR antagonist (C5aRA) intracutaneously injected in combination with DNCB treatment. The skin­fold thickness, number of total infiltrating leukocytes and mast cells infiltrating in skin tissue were measured. Interleukin­4 (IL­4) and interferon­Î³ (IFN­Î³) levels in skin tissue and IL­4, IFN­Î³, histamine and immunoglobulin E (IgE) levels in serum were measured using ELISA. The skin­fold thickness, numbers of total infiltrating leukocytes and mast cells in skin tissue, as well as levels of IL­4, IFN­Î³, histamine and IgE were significantly increased in mice with AD. However, simultaneous treatment with C5aRA significantly attenuated increases in skin fold thickness and the numbers of total infiltrating leukocytes and mast cells in skin tissue. Treatment with C5aRA also decreased IL­4 and IFN­Î³ levels in skin tissue, as well as the levels of IL­4, IFN­Î³, histamine and IgE in the serum. In conclusion, C5aRA inhibited AD in mice, possibly through suppression of the C5aR­mediated cascade action of mast cells.

Intraperitoneally administered biliverdin protects against UVB-induced skin photo-damage in hairless mice.

Oxidative stress is shown to be responsible for ultraviolet B (UVB) irradiation-induced skin cancer and premature aging. Biliverdin (BVD), a product of heme oxygenase-1, has strong anti-oxidant and anti-inflammatory properties. In the present study, we investigated the effects of BVD on UVB-induced skin photo-damage in hairless mice. Mice were divided into three groups: control group, UVB group (only UVB irradiation) and BVD+UVB group (mice were intraperitoneally injected with BVD before each UVB irradiation). Intraperitoneal BVD injection resulted in a significant photoprotective effect by reducing morphological and histopathological changes to the skin. BVD also exhibited a significant antioxidant effect by increasing the superoxide dismutase (SOD) level and decreasing the thiobarbituric acid reactive substances (TBARS) level compared with the control group. In addition, BVD activated biliverdin reductase (BVR) expression and inhibited the UVB-induced increase of p38 mitogen-activated protein kinase phosphorylation (p-p38MAPK), MMP (matrix metalloproteinase)-1 and MMP-3 expression (p<0.05). It also significantly decreased the interleukin (IL)-6 level compared with the UVB group (p<0.05). In conclusion, these data suggest that the intraperitoneally administered BVD can prevent UVB irradiation-induced skin photo-damage in hairless mice and that this is likely mediated by its antioxidant and anti-inflammatory mechanisms and cell signal regulatory action.

Effects of CASP5 gene overexpression on angiogenesis of HMEC-1 cells.

OBJECTIVES: The efficacy of gene overexpression of CASP5, a caspase family member, in angiogenesis in vitro and its mechanisms were clarified. METHODS: Human full-length CASP5 gene was delivered into human microvascular endothelial HMEC-1 cells by recombinant lentivirus. The infection was estimated by green fluorescent protein. MTT method was used to analyze the efficacy of gene overexpression in cell proliferation ability, and Matrigel was used to estimate its effects in angiogenesis ability of cells. Meanwhile, Western blot was used to analyze the effects of CASP5 gene overexpression on the expression levels of angpt-1, angpt-2, Tie2 and VEGF-1 in the cells, which were signaling pathway factors related to angiogenesis. RESULTS: Recombinant lentivirus containing human full-length CASP5 gene was packed and purified successfully, with virus titer of 1×10(8) TU/ml. The recombinant lentivirus was used to infect HMEC-1 cells with MOI of 1, leading to a cell infection rate of 100%. There were no significant effects of CASP5 gene overexpression on both cell proliferation ability and the expression level of angpt-1. Meanwhile, expressions of angpt-2 and VEGF-1 were both enhanced, while Tie2 expression was inhibited. Results indicated that CASP5 gene overexpression promoted angiogenesis of HMEC-1 cells. CONCLUSION: CASP5 gene overexpression significantly promoted angiogenesis ability of HMEC-1 cells, which was probably achieved by inhibiting angpt-1/Tie2 and promoting VEGF-1 signal pathway.

High prevalence of cardiovascular risk factors in patients with moderate or severe psoriasis in northern China.

Recent studies suggest that psoriasis is a systemic disorder associated with cardiovascular disease (CVD) risk factors, such as obesity, hypertension and dyslipidemia. However, these risk factors have not been widely recognized across different populations. This cross-sectional study aimed to examine the association of risk factors for CVD with psoriasis by comparing patients with psoriasis and matched controls in northern China. This study identified 291 patients with diagnosed moderate or severe psoriasis as cases and 445 age- and gender-matched subjects as controls. A significant association (P < 0.01) was observed between overall psoriasis incidence and smoking [odds ratio (OR), 2.96; 95 % confidence interval (CI) 2.09-4.09], alcohol consumption (OR, 3.77; 95 % CI 2.381-5.955), diabetes (OR, 2.79; 95 % CI 1.70-4.59), hypertension (OR, 2.19; 95 % CI 1.56-3.06) and hyperlipidemia (OR, 1.76; 95 % CI 1.29-2.40). Furthermore, hypertension correlated with the duration of psoriasis after adjustment for age and sex. Hyperlipidemia, smoking and alcohol consumption were related to the severity of the disease. Moreover, patients with psoriasis had lower levels of apolipoprotein B (ApoB) and lipoprotein (Lip) than did controls (P < 0.05). These data suggest that multiple risk factors for CVD are associated with psoriasis. CVD risk factor screening should be performed, and appropriate measures should be taken accordingly for psoriasis patients.

miR-573 regulates melanoma progression by targeting the melanoma cell adhesion molecule.

Melanoma is a malignant tumor of the melanocytes. microRNAs (miRNAs) are emerging as important regulators of cancer-related processes. A thorough understanding of miRNAs in melanoma progression is important for developing new therapeutic targets. miRNA expression was detected by quantitative PCR. In vitro, MTT assay, colony formation assay, invasion assay and flow cytometry analysis were performed to test the effect of miR-573 on melanoma cells. The effect of miR-573 in vivo was validated using a murine xenograft model. Using quantitative PCR, we found that the expression levels of miR-573 were lower in melanoma tissues and cell lines compared to normal skin tissues. miR-573 upregulation inhibited melanoma cell proliferation and invasion, and overexpression of melanoma cell adhesion molecule (MCAM) could alleviate the effect of miR-573 on melanoma cells. In vivo, miR-573 overexpression groups showed lower rates of tumor growth compared with the control group. In conclusion, our results demonstrate that the elevated MCAM expression due to miR-573 reduction is essential in melanoma initiation and progression.

Combined effect of 25-hydroxycholesterol and IL-1beta on IL-8 production in human colon carcinoma cell line (Caco-2).

Interleukin-1 beta (IL-1beta) is an important mediator in intestinal inflammation. IL-1beta promotes IL-8 production, which can be modulated by a number of factors, including oxidative stress. Interestingly, oxysterols, which are thought to contribute to inflammation in atherosclerotic plaques, are also produced by intestinal epithelial cells. Thus, we investigated the effect of oxysterols, including 25-hydroxycholesterol and 7beta-hydroxycholesterol, on IL-1beta-induced IL-8 production in Caco-2 cells (a human colon carcinoma cell line). Pre-treatment of Caco-2 cells with 25-hydroxycholesterol significantly enhanced IL-1beta-induced IL-8 expression at both mRNA and protein levels. However, 7beta-hydroxycholesterol showed very little effect on IL-8 production. Furthermore, pre-treatment with 25-hydroxycholesterol, followed by IL-1beta stimulation, enhanced IL-8 promoter activity beyond that observed with IL-1beta alone. These results suggest that 25-hydroxycholesterol enhances IL-1beta-induced IL-8 production, possibly by enhancing promoter activity.