Genome-Wide Association Study Identifies IFIH1 and HLA-DQB1*05:02 Loci Associated With Anti-NMDAR Encephalitis.

BACKGROUND AND OBJECTIVES: Anti-N-methyl-d-aspartate receptor (NMDAR) encephalitis is a rare autoimmune neurologic disorder, the genetic etiology of which remains poorly understood. Our study aims to investigate the genetic basis of this disease in the Chinese Han population. METHODS: We performed a genome-wide association study and fine-mapping study within the major histocompatibility complex (MHC) region of 413 Chinese patients with anti-NMDAR encephalitis recruited from 6 large tertiary hospitals and 7,127 healthy controls. RESULTS: Our genome-wide association analysis identified a strong association at the IFIH1 locus on chromosome 2q24.2 (rs3747517, p = 1.06 × 10-8, OR = 1.55, 95% CI, 1.34-1.80), outside of the human leukocyte antigen (HLA) region. Furthermore, through a fine-mapping study of the MHC region, we discovered associations for 3 specific HLA class I and II alleles. Notably, HLA-DQB1*05:02 (p = 1.43 × 10-12; OR, 2.10; 95% CI 1.70-2.59) demonstrates the strongest association among classical HLA alleles, closely followed by HLA-A*11:01 (p = 4.36 × 10-7; OR, 1.52; 95% CI 1.29-1.79) and HLA-A*02:07 (p = 1.28 × 10-8; OR, 1.87; 95% CI 1.50-2.31). In addition, we uncovered 2 main HLA amino acid variation associated with anti-NMDAR encephalitis including HLA-DQß1-126H (p = 1.43 × 10-12; OR, 2.10; 95% CI 1.70-2.59), exhibiting a predisposing effect, and HLA-B-97R (p = 3.40 × 10-8; OR, 0.63; 95% CI 0.53-0.74), conferring a protective effect. Computational docking analysis suggested a close relationship between the NR1 subunit of NMDAR and DQB1*05:02. DISCUSSION: Our findings indicate that genetic variation in IFIH1, involved in the type I interferon signaling pathway and innate immunity, along with variations in the HLA class I and class II genes, has substantial implications for the susceptibility to anti-NMDAR encephalitis in the Chinese Han population.

Correlation between double-stranded DNA and acute urticaria.

BACKGROUND: Acute urticaria is a prevalent inflammatory dermatosis characterized by fulminant wheals, often accompanied by severe pruritis. It may also cause nausea, vomiting, and abdominal pain. Numerous studies have substantiated the pivotal involvement of double-stranded DNA (dsDNA) in autoimmunity. However, the role of dsDNA in the pathogenesis of acute urticaria is unclear. METHODS: We measured serum dsDNA levels in patients and controls. The relationship between dsDNA levels and environmental exposures (temperature, ultraviolet [UV] index, and season) was investigated by correlating disease onset dates with archived meteorological data. Finally, we used quantitative PCR to determine the expressions of genes encoding dsDNA receptors, single-stranded RNA (ssRNA) receptors, exosome formation, and type I interferon in the peripheral blood of patients and controls. RESULTS: Serum dsDNA levels were significantly higher in patients with acute urticaria compared with controls (mean values 1.38 and 0.94 ng/ml, respectively, P < 0.001). dsDNA levels were higher in patients exposed to higher environmental temperatures and UV indices and were higher during the summer months. We also found that the expressions of genes encoding dsDNA receptors, ssRNA receptors, absent in melanoma factor 2 (AIM2)-related inflammatory factors, and interferon alpha were up-regulated in patients. CONCLUSIONS: We demonstrated that serum dsDNA levels are elevated in acute urticaria and are influenced by climatic factors such as temperature, ultraviolet index, and season. We also found that elevated dsDNA promotes the expression of AIM2-related factors and type I interferons. This study generates new hypotheses regarding the pathogenesis of acute urticaria and suggests novel therapeutic targets.

RasGRP1 influences imiquimod-induced psoriatic inflammation via T-cell activation in mice.

The vascular endothelial growth factor (VEGF) signal transduction pathway has been shown to be a potential target for the treatment of psoriasis. Ras guanyl-releasing protein 1 (RasGRP1), a downstream target gene of VEGF, regulates the development, homeostasis, and differentiation of T cells, but the contribution of RasGRP1 to psoriasis is limited. In this manuscript, we aimed to investigate the role of RasGRP1 in psoriasis. The RNA-Seq transcriptome sequencing data from the mouse model of psoriasis treated with IMQ (imiquimod) were analyzed. The effect of RasGRP1 was investigated through in vivo injection of activators or small molecular inhibitors, as well as adeno-associated virus injections. Gene knockout and NB-UVB (narrow-band ultraviolet B) treatments were utilized to interfere with the psoriatic mouse model. By transfection of lentivirus in vitro, the effect of RasGRP1 gene function on the secretion of psoriasis-related cytokines by T cells was confirmed. We showed that cutaneous VEGF and RasGRP1 were strongly activated in human psoriatic lesions and the skin of mice with IMQ-induced psoriasis. RasGRP1 deficiency and overexpression influence IMQ-induced psoriasis-like manifestations and skin inflammation in mice. VEGF, secreted mainly by epidermal cells, mediates psoriatic inflammation through the RasGRP1-AKT-NF-κB pathway. RasGRP1 is required for psoriasis development mediated by VEGF. These results confirmed the role of RasGRP1 in the pathogenesis of psoriasis and provided potential targets for clinical psoriasis treatment.

Rare mutations in NLRP3 and NLRP12 associated with familial cold autoinflammatory syndrome: two Chinese pedigrees.

Familial cold autoinflammatory syndrome (FCAS) is the mildest subtype of cryopyrin-associated periodic syndrome (CAPS) and is a rare inherited systemic autoinflammatory disease (SAID). CAPS is the consequence of a rare group of genetic disorders that are mostly reported in European and American populations, but scarcely reported in Chinese populations. NLRP3, NLRP12, PLCG2, and NLRC4 are known pathogenic genes associated with FCAS, and the aim of this study was to identify pathogenic mutations in two intact pedigrees of Chinese FCAS. We performed Sanger sequencing of genomic DNA samples from 25 affected and 32 unaffected members of the two intact pedigrees and analyzed the pathogenic mutations for their conservativeness using multiple sequence alignment tools. In addition, we reviewed previously reported pathogenic genes of FCAS and their pathogenicity classification and summarized the characteristics of different genotypes and phenotypes of FCAS. This study reported two intact FCAS pedigrees with different genotypes and phenotypes, the heterozygous mutation (p.V72M) in NLRP3 in pedigree 1 and the heterozygous mutation (p.R754H) in NLRP12 in pedigree 2. There are no reports targeting p.V72M in NLRP3 in FCAS1, and there are relatively few relevant phenotypic data on the clinical manifestations identified in previous pedigrees. Multiple sequence comparisons of NLRP3 indicate that the p.V72M mutation is highly conserved during evolution. Our study has enriched the understanding of the pathogenesis of FCAS, a rare disease especially in Asian populations. KEY POINTS: •The NLRP3 (p.V72M) variant was first discovered in the Chinese pedigree of FCAS1 •NLRP12 (p.R754H) variants are not conserved in multiple sequence alignments, but they are still co-segregated and expressed in the big Chinese diseased pedigree.

Calcium/calmodulin-dependent protein kinase IV promotes imiquimod-induced psoriatic inflammation via macrophages and keratinocytes in mice.

CaMK4 has an important function in autoimmune diseases, and the contribution of CaMK4 in psoriasis remains obscure. Here, we show that CaMK4 expression is significantly increased in psoriatic lesional skin from psoriasis patients compared to healthy human skin as well as inflamed skin from an imiquimod (IMQ)-induced mouse model of psoriasis compared to healthy mouse skin. Camk4-deficient (Camk4-/-) mice treated with IMQ exhibit reduced severity of psoriasis compared to wild-type (WT) mice. There are more macrophages and fewer IL-17A+γδ TCR+ cells in the skin of IMQ-treated Camk4-/- mice compared to IMQ-treated WT mice. CaMK4 inhibits IL-10 production by macrophages, thus allowing excessive psoriatic inflammation. Deletion of Camk4 in macrophages alleviates IMQ-induced psoriatic inflammation in mice. In keratinocytes, CaMK4 inhibits apoptosis as well as promotes cell proliferation and the expression of pro-inflammatory genes such as S100A8 and CAMP. Taken together, these data indicate that CaMK4 regulates IMQ-induced psoriasis by sustaining inflammation and provides a potential target for psoriasis treatment.

AURKA facilitates the psoriasis-related inflammation by impeding autophagy-mediated AIM2 inflammasome suppression.

Psoriasis is an immune-mediated genetic disease involving innate and the adaptive immune system. Aurora kinase A (AURKA) belongs to a seine/threonine kinases family and is elevated in lesional psoriatic tissues. This research aimed to investigate the effects of AURKA on psoriasis progression and whether it worked by regulating autophagy or inflammasome activation. The results showed that the expression of AURKA was higher in psoriasis tissue than that in the psoriasis skin. IFN-γ (100 ng/mL) plus poly (dA:dT) (2 mg/mL) induced the increased AURKA, secretion of IL-1ß, IL-18 and the active form of caspase-1 (p20). AURKA knockdown inhibited the inflammatory responses of keratinocytes and the activation of AIM2 inflammasome, and enhanced autophagy. 3MA (autophagy inhibitor) attenuated the effects of AURKA on AIM2 inflammasome. In addition, AURKA promoted the activation of the AKT/mTOR pathway. Akt inhibitor (PI-103) attenuated AIM2 inflammasome activation induced by Aurka overexpression. In conclusion, this research demonstrated that AURKA promoted the psoriasis-related inflammation by blocking autophagy-mediated AIM2 inflammasome suppression. AURKA has the potential to be explored as a new promising target for the treatment for psoriasis.

Low dose of emetine as potential anti-SARS-CoV-2 virus therapy: preclinical in vitro inhibition and in vivo pharmacokinetic evidences.

The global pandemic of COVID-19 has attracted extensive drug searching interets for the new coronavirus SARS-CoV-2. Although currently several of clinically used "old" drugs have been repurposed to this new disease for the urgent clinical investigation, there is still great demand for more effective therapies for the anti-infections. Here we report the discovery that an "old" drug Emetine could potently inhibit SARS-CoV-2 virus replication and displayed virus entry blocking effect in Vero cells at low dose. In addition, Emetine could significantly reduce the lipopolysaccharide (LPS) induced interleukin-6 (IL-6) protein level and moderately reduce the tumor necrosis factor (TNF-α) protein level in the M1 polarized THP-1 macrophages. In vivo animal pharmacokinetics (PK) study revealed that Emetine was enriched in the lung tissue and had a long retention time (over 12 h). With 1 mg/kg single oral dose, the effective concentration of Emetine in lung was up to 1.8 µM (mice) and 1.6 µM (rats) at 12 h, which is over 200-fold higher than the EC50 of the drug. The potent in vitro antiviral replication efficacy and the high enrichment in target tissue, combining with the well documented safety profiles in human indicate that low dose of Emetine might be a potentially effective anti-SARS-CoV-2 infection therapy. SUPPLEMENTARY INFORMATION: The online version contains supplementary material available at 10.1186/s43556-020-00018-9.

Differential occurrence of lysine 2-hydroxyisobutyrylation in psoriasis skin lesions.

Lysine 2-hydroxyisobutyrylation is a newly discovered posttranslational modification. Although this modification is an important type of protein acylation, its role in psoriasis remains unstudied. We compared lesional and nonlesional psoriasis skin samples from 45 psoriasis patients. The result showed that this highly conserved modification was found in large quantities in both normal and diseased dermal tissues. However, there were a number of clear and significant differences between normal and diseased skin tissue. By comparing, lysine 2-hydroxyisobutyrylation was upregulated at 94 sites in 72 proteins and downregulated at 51 sites in 44 proteins in lesional skin. In particular, the sites with the most significant downregulation of lysine 2-hydroxyisobutyrylation were found in S100A9 (ratio = 0.140, p-value = .000371), while the most upregulated site was found in tenascin (ratio = 3.082, p-value = .0307). Loci associated with psoriasis, including FUBP1, SERPINB2 and S100A9, also exhibited significant regulation. Analyses of proteome data revealed that SERPINB2 and S100A9 were differentially expressed proteins. And bioinformatics analysis suggest that the P13K-Akt signaling pathway was more enriched with lysine 2-hydroxyisobutyrylation in lesional psoriasis skin. Our study revealed that lysine 2-hydroxyisobutyrylation is broadly present in psoriasis skin, suggesting that this modification plays a role in psoriasis pathogenesis. SIGNIFICANCE: A newly discovered protein posttranslational modification, lysine 2-hydroxyisobutyrylation, has been found to occur in a wide variety of organisms and to participate in some important metabolic processes. In this study, lysine 2-hydroxyisobutyrylation in lesional psoriasis skin and nonlesional psoriasis skin was quantified and compared for the first time. We found a number of differentially modified proteins and sites in our comparisons. Interestingly, some of the identified proteins and pathways with significantly different modifications, such as S100A9 and the PI3K-Akt signaling pathway, have been previously reported to be associated with psoriasis. We hope that this research will provide new insights into psoriasis.

Genetic Study on Small Insertions and Deletions in Psoriasis Reveals a Role in Complex Human Diseases.

Genetic studies based on single-nucleotide polymorphisms have provided valuable insights into the genetic architecture of complex diseases. However, a large fraction of heritability for most of these diseases remains unexplained, and the impact of small insertions and deletions (InDels) has been neglected. We performed a comprehensive screen on the exome sequence data of 1,326 genes using the SOAP-PopIndel method for InDels in 32,043 Chinese Han individuals and identified 29 unreported InDels within 25 susceptibility genes associated with psoriasis. Specifically, we identified 12 common, 9 low-frequency, and 8 rare InDels that explained approximately 1.29% of the heritability of psoriasis. Further analyses identified KIAA0319, RELN, NCAPG, ABO, AADACL2, LMAN1, FLG, HERC5, CCDC66, LEKR1, AFF3, ABCG2, ANXA7, SYTL2,GIPR, METTL1, and FYCO1 as unreported genes for psoriasis. In addition, identified InDels were associated with the following reported genes: IFIH1, ERAP1, ERAP2, LNPEP, UBLCP1, and STAT3; unreported independent associations for exonic InDels were found within GJB2 and ZNF816A. Our study enriched the genetic basis and pathogenesis of psoriasis and highlighted the non-negligible impact of InDels on complex human diseases.

HLA-A*01:01 in MHC is associated with psoriatic arthritis in Chinese Han population.

To verify whether PsA-associated HLA alleles proposed in other populations are also related to PsA in Chinese Han population, a study of PsA susceptible alleles in the HLA-A, HLA-B, HLA-C and HLA-DRB1 alleles was presented for Chinese Han population. Genotyping was performed by Illumina Miseq platform (Illumina, USA). 50 subtypes and 77 subtypes of HLA-A, HLA-B, HLA-C and HLA-DRB1 with minor allele frequency (MAF) > 1% were genotyped from two-digit and four-digit resolution analysis in 111 PsA and 207 HCs (healthy controls) collected from Chinese Han population, respectively. Data handling, quality control and association analysis were performed using SPSS 25.0 software. In risk estimate, by mean of Bonferroni correction, a newfound four-digit allele HLA-A*01:01 [P = 5.5 × 10-4, OR 3.35 (1.69-6.66)], four-digit allele HLA-C*06:02 [P = 8.5 × 10-7, OR 3.80 (2.23-6.47)] and six two-digit alleles HLA-A*01 [P = 5.2 × 10-5, OR 3.43 (1.89-6.23)], HLA-B*13 [P = 4.0 × 10-6, OR 2.65 (1.76-4.01)], HLA-B*27 [P = 7.5 × 10-4, OR 5.84 (2.09-16.29)], HLA-B*57 [P = 5.8 × 10-5, OR 20.10 (4.65-86.83)], HLA-C*03 [P = 2.1 × 10-4, OR 0.40 (0.25-0.65)], HLA-C*06 [P = 1.9 × 10-12, OR 4.48 (2.95-6.81)] showed statistical significance by the univariate binary logistic regression analysis. Besides, in the binary logistic regression analysis with multiple variables, when the two alleles HLA-A*01:01 and HLA-C*06:02 were considered as covariates, HLA-A*01:01 [P = 2.7 × 10-3,OR 2.95 (1.46-5.98)] also showed significant association for PsA as risk factor, but may be not the main risk factor [HLA-C*06:02, P = 3.0 × 10-6, OR 3.68 (2.13-6.37)]. When all the above two-digit alleles were included as covariates, HLA-A*01 [P = 4.8 × 10-2, OR 2.00 (1.01-3.94)], HLA-B*13 [P = 4.2 × 10-5, OR 2.62 (1.65-4.16)], HLA-B*27 [P = 1.7 × 10-4, OR 7.62 (2.64-21.96)], HLA-B*57 [P = 2.97 × 10-4, OR 15.90 (3.55-71.18)], HLA-C*06 [P = 6.1 × 10-5, OR 2.70 (1.66-4.40)] showed significant for PsA as risk factors, HLA-C*03 [OR 0.65 (0.39-1.09), P = 0.10] showed no association with PsA. In conclusion, we assessed HLA-A, HLA-B, HLA-C and HLA-DRB1 alleles in PsA cohort of Chinese Han population, found HLA-A*01:01 and HLA-A*01 may be the susceptible genes associated with PsA, and also confirmed the association of four loci with PsA in Chinese Han population. These findings may extend the susceptibility HLA alleles of PsA and help in developing possible genetic markers to predict PsA.

Mutational analysis of epidermal and hyperproliferative type I keratins in mild and moderate psoriasis vulgaris patients: a possible role in the pathogenesis of psoriasis along with disease severity.

BACKGROUND: Mutations in keratin proteins have been vastly associated with a wide array of genodermatoses; however, mutations of keratins in psoriasis have not been fully investigated. The main aim of the current research was to identify the mutation in K14, K10, K16, and K17 genes in two stages of psoriasis patients. METHODS: Ninety-six psoriatic skin biopsies were collected. mRNA transcript of K14, K10, K16, and K17 was prepared, amplified, and sequenced. Sanger sequences of all keratins were further validated for mutational analysis using Mutation Surveyor and Alamut Visual. Then, in silico analysis of protein stability and protein and gene expression of all keratins was performed and validated. RESULTS: Out of 44 mutations, about 75% of keratins are highly pathogenic and deleterious. Remaining 25% mutations are less pathogenic and tolerated in nature. In these 33 deleterious mutations were immensely found to decrease keratin protein stability. We also found a correlation between keratin and Psoriasis Area and Severity Index score which added that alteration in keratin gene in skin causes severity of psoriasis. CONCLUSIONS: We strongly concluded that acanthosis and abnormal terminal differentiation was mainly due to the mutation in epidermal keratins. In turn, disease severity and relapsing of psoriasis are mainly due to the mutation of hyperproliferative keratins. These novel keratin mutations in psoriatic epidermis might be one of the causative factors for psoriasis.

DNA methylation-based subclassification of psoriasis in the Chinese Han population.

Psoriasis (Ps) is an inflammatory skin disease caused by genetic and environmental factors. Previous studies on DNA methylation (DNAm) found genetic markers that are closely associated with Ps, and evidence has shown that DNAm mediates genetic risk in Ps. In this study, Consensus Clustering was used to analyze DNAm data, and 114 Ps patients were divided into three subclassifications. Investigation of the clinical characteristics and copy number variations (CNVs) of DEFB4, IL22, and LCE3C in the three subclassifications revealed no significant differences in gender ratio and in Ps area and severity index (PASI) score. The proportion of late-onset ( ≥ 40 years) Ps patients was significantly higher in type I than in types II and III (P = 0.035). Type III contained the smallest proportion of smokers and the largest proportion of non-smoking Ps patients (P = 0.086). The CNVs of DEFB4 and LCE3C showed no significant differences but the CNV of IL22 significantly differed among the three subclassifications (P = 0.044). This study is the first to profile Ps subclassifications based on DNAm data in the Chinese Han population. These results are useful in the treatment and management of Ps from the molecular and genetic perspectives.

Bach2 regulates aberrant activation of B cell in systemic lupus erythematosus and can be negatively regulated by BCR-ABL/PI3K.

OBJECTIVE: This study was aimed to explore the effect of Bach2 on B cells in systemic lupus erythematosus (SLE), as well as the underlying mechanisms. METHODS: Expression of Bach2, phosphorylated-Bach2 (p-Bach2), Akt, p-Akt and BCR-ABL (p210) in B cells isolated from SLE patients and the healthy persons were assessed by Western blot. Immunofluorescence staining was performed to assess the localization of Bach2 in B cells. Enzyme-linked immunosorbent assay (ELISA) was employed to detect IgG produced by B cells. Cell counting kit-8 (CCK-8) and Annexin-V FITC/PI double staining assay were adopted to evaluate cell proliferation and apoptosis in B cells, respectively. RESULTS: Compared to the healthy controls, Bach2, p-Akt and p210 were significantly decreased, while nuclear translocation of Bach2, IgG, CD40 and CD86 obviously up-regulated in B cells from SLE patients. Bach2 significantly inhibited the proliferation, promoted apoptosis of B cells from SLE patients, whereas BCR-ABL dramatically reversed cell changes induced by Bach2. Besides, BCR-ABL also inhibited nuclear translocation of Bach2 in B cells from SLE patients. Further, LY294002 treatment had no effect on decreased expression of Bach2 induced by BCR-ABL, but significantly eliminated BCR-ABL-induced phosphorylation of Bach2 and restored reduced nuclear translocation of Bach2 induced by BCR-ABL in B cells from SLE. CONCLUSIONS: Bach2 may play a suppressive role in B cells from SLE, and BCR-ABL may inhibit the nuclear translocation of Bach2 via serine phosphorylation through the PI3K pathway.

LMO4 Is a Disease-Provocative Transcription Coregulator Activated by IL-23 in Psoriatic Keratinocytes.

Psoriasis is an autoimmune disease characterized by abnormal differentiation and hyperproliferation of epidermal keratinocytes. LIM-domain only protein 4 (LMO4) is a transcription factor coregulator that promotes the assembly of multiprotein complexes to regulate mammary epithelium and keratinocyte differentiation and proliferation during embryogenesis. In this study, LMO4 has been found to be abundantly expressed in psoriatic epidermis. LMO4 expression is increased in human keratinocytes induced to differentiate by calcium ex vivo, and LMO4 overexpression induces spontaneous differentiation and growth acceleration of human keratinocytes in the absence of calcium. IL-23, a cytokine highly expressed in psoriatic skin lesions, induces differentiation and promotes proliferation of human keratinocytes. The IL-23-mediated effects are accompanied by an increase in LMO4 expression mediated by signal transducer and activator of transcription 3 through an IL-23/acutely transforming retrovirus AKT8 in rodent T-cell lymphoma/signal transducer and activator of transcription 3 pathway in keratinocytes. Knockdown of LMO4 effectively inhibits differentiation and growth of keratinocytes both ex vivo and in IL-23-injected ears of mice. LMO4 appears to mediate IL-23-related responses in psoriatic keratinocytes and is a potential therapeutic target in psoriasis.

Disorder of the mevalonate pathway inhibits calcium-induced differentiation of keratinocytes.

Mutation of genes encoding the enzymes of the mevalonate pathway cause a variety of diseases, including skin disorders. Mutation of four genes in this pathway, including mevalonate kinase, phosphomevalonate kinase, mevalonate diphosphate decarboxylase and farnesyl diphosphate synthase, have demonstrated to be responsible for porokeratosis (PK). However, the pathogenesis of PK remains unclear. In the present study, specific enzyme inhibitors of the mevalonate pathway, including pravastatin (PRA), alendronate (ALD), farnesyl transferase inhibitor (FTI­277) and geranylgeranyl transferase inhibitor (GGTI­298), were used to investigate the effect on differentiation of keratinocytes (KCs). Western blotting demonstrated that PRA, ALD, FTI­277 or GGTI­298 alone, or in combination, inhibited the expression level of calcium­induced differentiation maker involucrin (INV) in KCs. ALD and PRA induced greater inhibition of INV compared with FTI­277 and GGTI­298 treatment. These inhibitors additionally influenced the expression levels of keratin1. Mechanistic studies revealed that treatment of cells with inhibitors decreased the expression levels of p53 and Notch1, and regulated activation of the mitogen activated protein kinase and phosphoinositide­3­kinase/protein kinase B signaling pathways. The results of the present study suggested that regulation of the mevalonate pathway may be necessary for differentiation of KCs, and the pathogenesis of disseminated superficial actinic PK.

An in-depth analysis identifies two new independent signals in 11q23.3 associated with vitiligo in the Chinese Han population.

BACKGROUND: Vitiligo is an autoimmune disease, characterized by progressive loss of skin pigmentation, which is caused by the interactions of multiple factors, such as heredity, immunity and environment. Recently, a single nucleotide polymorphism (SNP) rs638893 at 11q23.3 region was identified as a risk factor for vitiligo in genome-wide association studies and multiple SNPs in this region have been associated with other autoimmune diseases. OBJECTIVE: This study aims to identify additional susceptibility variants associated with vitiligo at 11q23.3 in the Chinese Han population. METHODS: We selected and genotyped 26 SNPs at 11q23.3 in an independent cohort including 2924 cases and 4048 controls using the Sequenom MassArray iPLEX® system. Bonferroni adjustment was used for multiple comparisons and P value <1.92×10-3 (0.05/26) was considered statistically significant. RESULTS: The A allele of rs613791 and G allele of rs523604 located in CXCR5 were observed to be significantly associated with vitiligo (OR=1.21, 95% CI: 1.11-1.31, P=1.20×10-5; OR=1.14, 95% CI: 1.07-1.23, P=1.90×10-4, respectively). The C allele of rs638893 (a previously reported one) located upstream of DDX6 was also significantly associated with vitiligo (OR=1.25, 95% CI: 1.12-1.38, P=3.04×10-5). The genotypes distribution of 3 SNPs also showed significant differences between case and control (rs613791: P=7.00×10-6, rs523604: P=4.00×10-3, rs638893: P=1.20×10-5, respectively). The two newly identified SNPs (rs613791 and rs523604) showed independent associations with vitiligo by linkage disequilibrium analysis and conditional logistic regression. CONCLUSIONS: The study identified two new independent signals in the associated locus 11q23.3 for vitiligo. The presence of multiple independent variants emphasizes an important role of this region in disease susceptibility.

Interleukin-15 inhibits the expression of differentiation markers induced by Ca(2+) in keratinocytes.

Interleukin (IL)-15 is an important proinflammatory cytokine that can protect epidermal keratinocytes (KCs) from ultraviolet-induced apoptosis and plays a role in the pathogenesis of psoriasis. However, the impact of IL-15 on KC differentiation remains unknown. In this study, isolated human primary epidermal KCs were treated with various concentrations of IL-15 for different times, and the expression of differentiation markers (keratin 1, involucrin and loricrin) and p53 as well as the activation of ERK, AKT and Notch induced by IL-15 in the absence or presence of Ca(2+) was detected by real-time PCR and Western blot. The results showed that stimulation with Ca(2+) alone increased the expression of KC differentiation markers and p53 and promoted the activation of Notch1. Pretreatment with IL-15 resulted in a decrease in the Ca(2+) -induced expression of KC differentiation markers and p53. Additionally, Ca(2+) continually inhibited the phosphorylation of ERK1/2 and activated AKT, and IL-15 reduced the effect of Ca(2+) on ERK1/2 and AKT. FR180204, a specific inhibitor of ERK1/2 phosphorylation, slightly attenuated the effect of Ca(2+) on the expression of differentiation markers and p53 and the activation of Notch1. In contrast, MK-2206, an inhibitor of pAKT, strongly blocked the expression of the differentiation markers and p53 and the activation of Notch1. An anti-IL-15 antibody neutralized the effect of IL-15 on KC differentiation. These results indicate that IL-15 inhibits the Ca(2+) -induced differentiation of KCs, mainly via the attenuation of Ca(2+) -stimulated PI3K-AKT signalling.

Genome-wide search followed by replication reveals genetic interaction of CD80 and ALOX5AP associated with systemic lupus erythematosus in Asian populations.

OBJECTIVES: Genetic interaction has been considered as a hallmark of the genetic architecture of systemic lupus erythematosus (SLE). Based on two independent genome-wide association studies (GWAS) on Chinese populations, we performed a genome-wide search for genetic interactions contributing to SLE susceptibility. METHODS: The study involved a total of 1 659 cases and 3 398 controls in the discovery stage and 2 612 cases and 3 441 controls in three cohorts for replication. Logistic regression and multifactor dimensionality reduction were used to search for genetic interaction. RESULTS: Interaction of CD80 (rs2222631) and ALOX5AP (rs12876893) was found to be significantly associated with SLE (OR_int=1.16, P_int_all=7.7E-04 at false discovery rate<0.05). Single nuclear polymorphism rs2222631 was found associated with SLE with genome-wide significance (P_all=4.5E-08, OR=0.86) and is independent of rs6804441 in CD80, whose association was reported previously. Significant correlation was observed between expression of these two genes in healthy controls and SLE cases, together with differential expression of these genes between cases and controls, observed from individuals from the Hong Kong cohort. Genetic interactions between BLK (rs13277113) and DDX6 (rs4639966), and between TNFSF4 (rs844648) and PXK (rs6445975) were also observed in both GWAS data sets. CONCLUSIONS: Our study represents the first genome-wide evaluation of epistasis interactions on SLE and the findings suggest interactions and independent variants may help partially explain missing heritability for complex diseases.

Knockdown of asparagine synthetase by RNAi suppresses cell growth in human melanoma cells and epidermoid carcinoma cells.

Melanoma, the most aggressive form of skin cancer, causes more than 40,000 deaths each year worldwide. And epidermoid carcinoma is another major form of skin cancer, which could be studied together with melanoma in several aspects. Asparagine synthetase (ASNS) gene encodes an enzyme that catalyzes the glutamine- and ATP-dependent conversion of aspartic acid to asparagine, and its expression is associated with the chemotherapy resistance and prognosis in several human cancers. The present study aims to explore the potential role of ASNS in melanoma cells A375 and human epidermoid carcinoma cell line A431. We applied a lentivirus-mediated RNA interference (RNAi) system to study its function in cell growth of both cells. The results revealed that inhibition of ASNS expression by RNAi significantly suppressed the growth of melanoma cells and epidermoid carcinoma cells, and induced a G0/G1 cell cycle arrest in melanoma cells. Knockdown of ASNS in A375 cells remarkably downregulated the expression levels of CDK4, CDK6, and Cyclin D1, and upregulated the expression of p21. Therefore, our study provides evidence that ASNS may represent a potential therapeutic target for the treatment of melanoma.