The transcription factor HMGB2 indirectly regulates APRIL expression and Gd-IgA1 production in patients with IgA nephropathy.

BACKGROUND: IgA nephropathy (IgAN) is the most common primary glomerulonephritis worldwide. Proliferation-inducing ligand (APRIL) was identified as an important cause of glycosylation deficiency of IgA1 (Gd-IgA1), which can 'trigger' IgAN. Our previous study indicated that high migration group protein B2 (HMGB2) in peripheral blood mononuclear cells from patients with IgAN was associated with disease severity, but the underlying mechanism remains unclear. MATERIALS AND METHODS: The location of HMGB2 was identified by immunofluorescence. qRT-PCR and Western blotting were used to measure HMGB2, HMGA1, and APRIL expression. Gd-IgA1 levels were detected by enzyme-linked immunosorbent assay (ELISA). In addition, we used DNA pull-down, protein profiling, and transcription factor prediction software to identify proteins bound to the promoter region of the APRIL gene. RNA interference and coimmunoprecipitation (Co-IP) were used to verify the relationships among HMGB2, high mobility group AT-hook protein 1 (HMGA1), and APRIL. RESULTS: HMGB2 expression was greater in IgAN patients than in HCs and was positively associated with APRIL expression in B cells. DNA pull-down and protein profiling revealed that HMGB2 and HMGA1 bound to the promoter region of the APRIL gene. The expression levels of HMGA1, APRIL, and Gd-IgA1 were downregulated after HMGB2 knockdown. Co-IP indicated that HMGB2 binds to HMGA1. The Gd-IgA1 concentration in the supernatant was reduced after HMGA1 knockdown. HMGA1 binding sites were predicted in the promoter region of the APRIL gene. CONCLUSION: HMGB2 expression is greater in IgAN patients than in healthy controls; it promotes APRIL expression by interacting with HMGA1, thereby inducing Gd-IgA1 overexpression and leading to IgAN.

The comprehensive analysis of clinical trials registration for IgA nephropathy therapy on ClinicalTrials.gov.

OBJECTIVES: IgA Nephropathy (IgAN) is common chronic kidney disease with a high incidence. This study aims to analyze comprehensively therapeutic clinical trials for IgAN registered on ClinicalTrials.gov. METHODS: Therapeutic trials for IgAN registered on ClinicalTrials.gov. up to 15 August 2021 were obtained. The general characteristics, features of experimental design, treatment strategies, and some main inclusion criteria and outcome measures were accessed. RESULTS: A total of 104 therapeutic clinical trials for IgAN were extracted on ClinicalTrials.gov up to 15 August 2021. Most of these trials explored the treatment for primary IgAN confirmed by renal biopsy in adults. Only 9% of all selected trials had results. Forty-five percent of trials recruited 50 or fewer participants, and 73% were adults or older adults. 99% of trials were interventional studies, and of all the interventional trials, 70% of trials were randomized, and 68% exercised a parallel assignment of intervention model. Immunosuppression was the most studied for the treatment of IgAN. Moreover, many novel agents had been increasingly studied in recent years. Furthermore, the inclusion criteria and primary outcome measures in these trials were diverse, and the level of proteinuria and change of proteinuria levels were the most used as inclusion criteria and primary outcome, respectively. CONCLUSIONS: The majority of therapeutic trials for IgAN were randomized, none masking and parallel-assignment interventional studies, primarily recruiting adult patients as research subjects. These trials had relatively small sample sizes and short observation. Thus, more large-scale, multicenter, and randomized controlled trials are still needed to improve the management for IgAN.

Elevated Endostatin Expression Is Regulated by the pIgA Immune Complex and Associated with Disease Severity of IgA Nephropathy.

BACKGROUND/AIMS: Renal vascular injury accounts for the poor outcomes of patients with IgA nephropathy (IgAN). In this study, we investigated whether endostatin, a potent inhibitor of angiogenesis, is associated with IgAN. METHODS: Serum endostatin levels were detected in patients with IgAN, disease controls, and healthy controls, and the correlation among endostatin and clinicopathologic manifestations, as well as prognosis in patients with IgAN, was analyzed. In addition, serum endostatin levels were compared in patients "before" and "after" treatment. Data on endostatin expression in the renal interstitium of patients with IgAN were downloaded and analyzed from the GSE35489 array in the GEO database. The poly-IgA1 (pIgA) immune complex is widely recognized as the "trigger" of IgAN initiation. pIgA in the plasma of patients was extracted and used to stimulate human glomerular endothelial cells (GECs). Endostatin, IL-6, and CXCL1 in the cell supernatant were detected by ELISA kits. RESULTS: We found that serum endostatin levels were significantly increased in patients with IgAN, as was endostatin expression in the renal interstitium. Patients with IgAN were divided into 2 groups according to the median value. The high endostatin expression group had significantly higher levels of serum creatinine and BUN and more severe tubular/interstitial damage. Moreover, patients with arteriolar injury and endothelial cell proliferation had higher serum endostatin levels. Patients with high serum endostatin levels had poor prognosis. According to the in vitro experiment, the GEC apoptosis rate and the supernatant levels of endostatin, IL-6, and CXCL1 were significantly increased following pIgA stimulation. CONCLUSION: Our study found that elevated endostatin expression was associated with disease severity and poor prognosis in patients with IgAN and can be upregulated by pIgA, but how it participates in the pathogenesis of IgAN deserves further exploration.

MicroRNAs in IgA nephropathy.

IgA nephropathy (IgAN) is the most common primary glomerulonephritis worldwide. It is considered that the pathogenesis of IgAN involves the 'multiple hit theory' and the immune-inflammatory mechanism; however, these theories have certain limitations. The gold standard for diagnosing IgAN is still renal biopsy. Although renal biopsy is accurate, it is traumatic and is associated with some risks and limitations, so there is a need for non-invasive diagnostic methods. According to recent studies, microRNAs (miRNAs) play important roles in the occurrence and development of IgAN; thus, they provide the possibility of the noninvasive diagnosis of IgAN and also have some value in predicting prognosis. This review summarizes the current research status of miRNAs in the occurrence, development, diagnosis, and prognosis of IgAN. We also highlight some interesting and challenging points that require further study.

Variation in complement factor H affects complement activation in immunoglobulin A vasculitis with nephritis.

BACKGROUND: Immunoglobulin A (IgA) vasculitis with nephritis (IgAVN) and IgA nephropathy (IgAN) are widely considered as related diseases. Considerable evidences support the notion of involvement of complement activation in both IgAVN and IgAN. Our previous studies identified a genetic variant in complement factor H (CFH), rs6677604, as an IgAN-susceptible variant by genome-wide association study, and further confirmed its linkage to CFHR3-1Δ and proved its influence on complement activation and thereby on IgAN susceptibility. AIM: To explore the role of rs6677604 in complement activation of IgAVN. METHODS: In this study, we enrolled 632 patients with IgAVN, 1178 patients with IgAN and 902 healthy controls. The genotype of rs6677604 was measured by TaqMan allele discrimination assays or was extracted from genome-wide association study data. RESULTS: The frequency of the rs6677604-A allele was significantly higher in IgAVN than in IgAN. However, no significant differences were observed between IgAVN and the controls. Higher complement factor H (FH) levels were observed in IgAVN than IgAN, and positive correlation between circulating FH and C3 levels was present in IgAVN. In both IgAVN and IgAN, rs6677604-A was associated with less intensity of glomerular C3 deposits. In agreement with the higher frequency of rs6677604-A in IgAVN, the glomerular C3 deposits of patients with IgAVN were less intense than those in IgAN. CONCLUSION: Our findings suggest that genetic variation in CFH (rs6677604) is involved in the phenotype of complement activation in both IgAVN and IgAN. Moreover, rs6677604 might contribute to the difference of complement activation intensity between IgAVN and IgAN.

Searching for valuable differentially expressed miRNAs in postmenopausal osteoporosis by RNA sequencing.

AIM: Postmenopausal osteoporosis is a systemic and chronic bone disease in women. In order to understand the pathological mechanism of postmenopausal osteoporosis, we aimed to find the potential differentially expressed miRNAs in the disease. METHODS: Firstly, RNA sequencing was used to identify differentially expressed miRNAs, followed by the construction of the miRNA-target mRNA regulatory network. Then, Gene Ontology and the Kyoto Encyclopedia of Genes and Genomes were used to analyze the biological function of target mRNAs. Finally, electronic validation of identified differentially expressed miRNAs and target mRNAs was performed. RESULTS: A total of 33 differentially expressed miRNAs (18 upregulated and 15 downregulated miRNAs) and 6820 miRNA-mRNA pairs were identified. Among which, seven miRNAs with high degree including hsa-miR-17-5p, hsa-miR-1-3p, hsa-miR-193b-3p, hsa-miR-125b-5p, hsa-miR-10b-5p, hsa-miR-100-5p and hsa-miR-30a-3p were obtained in the miRNA-mRNA regulatory network. TGF-beta was the most significantly enriched signaling pathway of target mRNAs. The electronic validation result of hsa-miR-1-3p, hsa-miR-193b-3p, hsa-miR-10b-5p, hsa-miR-100-5p, hsa-miR-133b, hsa-miR-708-5p, CRK, RAB5C, CCND1 and PCYOX1 was consisted with the RNA sequencing analysis. CONCLUSION: Dysfunctional miRNAs may play significant roles in postmenopausal osteoporosis.

Elevated hsa-miR-590-3p expression down-regulates HMGB2 expression and contributes to the severity of IgA nephropathy.

Peripheral blood mononuclear cells (PBMCs) play important roles in the pathogenesis of IgA nephropathy (IgAN). Our study aimed to provide a deep understanding of IgAN and focused on the dysregulation of hsa-miR-590-3p and its target gene HMGB2 in PBMCs. Three gene expression profile datasets (GSE14795, GSE73953 and GSE25590) were downloaded from the GEO database. The DEGs (differentially expressed genes)-miRNA network that was associated with IgAN was constructed by Cytoscape, and HMGB2 and hsa-miR-590-3p were selected for further exploration. The dual-luciferase reporter system was utilized to verify their interaction. Then, the expression levels of HMGB2 and hsa-miR-590-3p in PBMCs were detected by qPCR in another cohort, and the correlation of their expression levels with the clinical pathological manifestations and serum Gd-IgA1(galactose-deficient IgA1) levels was also investigated. HMGB2 was identified as the target gene of hsa-miR-590-3p. Furtherly, the elderly patients had higher HMGB2 expression levels than the expression levels of the younger patients. As the serum creatinine, serum BUN levels increased, the expression of HMGB2 decreased; Besides, the HMGB2 expression was positively correlated with serum complement 3(C3) levels, and it also had a negative correlation with the diastolic blood pressure, but not reach statistical significance. What is more, both hsa-miR-590-3p and HMGB2 expression had a slight correlation tendency with serum Gd-IgA1 levels in the whole population. In conclusion, HMGB2, the target gene of hsa-miR-590-3p, was identified to correlate with the severity of IgAN, and this provides more clues for the pathogenesis of IgAN.

Rare Variants in the Complement Factor H-Related Protein 5 Gene Contribute to Genetic Susceptibility to IgA Nephropathy.

A recent genome-wide association study of IgA nephropathy (IgAN) identified 1q32, which contains multiple complement regulatory genes, including the complement factor H (CFH) gene and the complement factor H-related (CFHRs) genes, as an IgAN susceptibility locus. Abnormal complement activation caused by a mutation in CFHR5 was shown to cause CFHR5 nephropathy, which shares many characteristics with IgAN. To explore the genetic effect of variants in CFHR5 on IgAN susceptibility, we recruited 500 patients with IgAN and 576 healthy controls for genetic analysis. We sequenced all exons and their intronic flanking regions as well as the untranslated regions of CFHR5 and compared the frequencies of identified variants using the sequence kernel association test. We identified 32 variants in CFHR5, including 28 rare and four common variants. The distribution of rare variants in CFHR5 in patients with IgAN differed significantly from that in controls (P=0.002). Among the rare variants, in silico programs predicted nine as potential functional variants, which we then assessed in functional assays. Compared with wild-type CFHR5, three recombinant CFHR5 proteins, CFHR5-M (c.508G>A/p.Val170Met), CFHR5-S (c.533A>G/p.Asn178Ser), and CFHR5-D (c.822A>T/p.Glu274Asp), showed significantly higher C3b binding capacity (CFHR5-M: 109.67%±3.54%; P=0.02; CFHR5-S: 174.27%±9.78%; P<0.001; CFHR5-D: 127.25%±1.75%; P<0.001), whereas another recombinant CFHR5 (c.776T>A/p.Leu259Termination) showed less C3b binding (56.89%±0.57%; P<0.001). Our study found that rare variants in CFHR5 may contribute to the genetic susceptibility to IgAN, which suggests that CFHR5 is an IgAN susceptibility gene.

Variants in Complement Factor H and Complement Factor H-Related Protein Genes, CFHR3 and CFHR1, Affect Complement Activation in IgA Nephropathy.

Complement activation is common in patients with IgA nephropathy (IgAN) and associated with disease severity. Our recent genome-wide association study of IgAN identified susceptibility loci on 1q32 containing the complement regulatory protein-encoding genes CFH and CFHR1-5, with rs6677604 in CFH as the top single-nucleotide polymorphism and CFHR3-1 deletion (CFHR3-1∆) as the top signal for copy number variation. In this study, to explore the clinical effects of variation in CFH, CFHR3, and CFHR1 on IgAN susceptibility and progression, we enrolled two populations. Group 1 included 1178 subjects with IgAN and available genome-wide association study data. Group 2 included 365 subjects with IgAN and available clinical follow-up data. In group 1, rs6677604 was associated with mesangial C3 deposition by genotype-phenotype correlation analysis. In group 2, we detected a linkage between the rs6677604-A allele and CFHR3-1∆ and found that the rs6677604-A allele was associated with higher serum levels of CFH and lower levels of the complement activation split product C3a. Furthermore, CFH levels were positively associated with circulating C3 levels and negatively associated with mesangial C3 deposition. Moreover, serum levels of the pathogenic galactose-deficient glycoform of IgA1 were also associated with the degree of mesangial C3 deposition in patients with IgAN. Our findings suggest that genetic variants in CFH, CFHR3, and CFHR1 affect complement activation and thereby, predispose patients to develop IgAN.

Genome-wide analysis of long noncoding RNAs as cis-acting regulators of transcription factor-encoding genes in IgA nephropathy.

BACKGROUND: IgA nephropathy (IgAN) is the most common form of primary glomerulonephritis in the world, but the disease pathogenesis noncoding is yet to be elucidated. Previous studies have revealed regulatory functions for long noncoding RNA (lncRNA) in various diseases; however, the roles of lncRNA in IgAN and regulation of transcription factors (TFs) have been scarcely investigated. METHODS: Renal tissue samples (n = 5) from patients with IgAN and control samples (n = 4) were collected and RNA sequencing (RNA-seq) was performed. Four software programs were employed for lncRNA prediction. GO (Gene Ontology)/KEGG (Kyoto Encyclopedia of Genes and Genomes) were employed for analysis of the identified differentially expressed genes (DEGs). A regulatory network model of DE lncRNA-TF-DEG was developed, and the levels of expression of key lncRNAs, TFs, and corresponding target genes were assessed using qRT-PCR and immunofluorescence. RESULTS: The current study identified 674 upregulated and 1,011 downregulated DE mRNAs and 260 upregulated and 232 downregulated DE lncRNAs in IgAN samples compared with control samples. The upregulated DE mRNAs showed enrichment in cell adhesion and collagen glial fiber organization pathways. The DE lncRNAs-DE mRNAs showing co-expression are associated with transmembrane transport. A novel regulatory network model of lncRNA-TF-DEG has been developed. This study identified seven TFs that are cis-regulated by 6 DE lncRNAs, and show co-expression with 132 DEGs (correlation coefficient ≥ 0.8, P ≤ 0.01), generating 158 pairs that showed co-expression. The lncRNAs NQO1-DT and RP5-1057120.6 were found to be highly expressed in IgAN samples. The TFs vitamin D Receptor (VDR) and NFAT5, along with their target genes were also aberrantly expressed. CONCLUSION: Key lncRNAs and TFs centrally associated with IgAN have been identified in this study. A regulatory network model of lncRNA-TF-mRNA was constructed. Further studies on the genes identified herewith could provide insight into the pathogenesis of IgAN.

Improved Antibacterial Properties of Polylactic Acid-Based Nanofibers Loaded with ZnO-Ag Nanoparticles through Pore Engineering.

In the post-epidemic era, bio-based protective fiber materials with active protective functions are of utmost importance, not only to combat the spread of pathogens but also to reduce the environmental impact of petroleum-based protective materials. Here, efficient antibacterial polylactic acid-based (PLA-based) fibers are prepared by solution blow spinning and their pore structures are regulated by controlling the ratio of the solvent components in the spinning solutions. The porous PLA-based fibers exhibit antibacterial efficiencies of over 99% against Escherichia coli and over 98% against Bacillus subtilis, which are significantly higher than that of the nonporous PLA-based fibers. The excellent antibacterial property of the porous PLA-based fibers can be attributed to their high porosity, which allows antibacterial nanoparticles to be released more easily from the fibers, thus effectively killing pathogenic microorganisms. Moreover, pore structure regulation can also enhance the mechanical property of the PLA-based fiber materials. Our approach of regulating the microstructure and properties of the PLA-based fibers through pore engineering can be extended to other polymer fiber materials and is suitable for polymer-based composite systems that require optimal performance through sufficient exposure of doped materials.

Tacrolimus treatment after short-term intravenous methylprednisolone in incipient minimal change disease for adults: A retrospective analysis.

The present study aimed to investigate the efficacy and safety of tacrolimus for treating incipient minimal change disease in adults. The clinical data of 52 adult patients with minimal change disease of nephrotic syndrome diagnosed by renal biopsy in the First affiliated hospital of Zhengzhou University between August 2013 and August 2015 were retrospectively analyzed. According to the treatment plan, the patients were divided into a tacrolimus group and a glucocorticoid group. The efficacy and safety of tacrolimus in the treatment of minimal change disease in adult patients was analyzed and compared with that of glucocorticoids. The results revealed that the baseline characteristics of the two groups were similar (P>0.05). At 24 weeks, there was a significant difference in serum albumin between the two groups (P<0.01). The serum albumin levels of tacrolimus group was higher compared with the glucocorticoid group. In addition, the complete remission rates in the tacrolimus and glucocorticoid groups were 93.75 and 77.8%, respectively (P=0.095), and the mean complete remission time was 6.33±4.21 and 5.14±2.45 weeks, respectively (P=0.175). The relapse rate was 12.5 and 22.2% in the tacrolimus and glucocorticoid groups, respectively (P=0.368). During the follow-up, in tacrolimus group, the incidence of new onset diabetes or impaired glucose tolerance, osteoporosis, infection, abnormal liver function, Cushing's syndrome, acne and gastrointestinal symptoms were significantly less than those of glucocorticoids (P<0.05). In conclusion, tacrolimus treatment after short-time intravenous methylprednisolone is an effective treatment option with fewer adverse effects in adult onset minimal change disease.

A botanical medicine dragon's blood exhibited clinical antithrombosis efficacy similar to low molecular weight heparin.

Deep vein thrombosis (DVT) is a common complication following traumatic fracture with a 0.5%-1% annual incidence. Low molecular weight heparin (LMWH) is the most commonly used anticoagulation drug for DVT prevention, but treatment with LMWH is invasive. Our aim is to compare the antithrombotic effect of dragon's blood, an oral botanical anticoagulant medicine approved by the Chinese FDA, with LMWH in patients undergoing hip fracture surgery and to explore the molecular mechanisms of anticoagulation treatment. Our study recruited patients and divided them into LMWH and dragon's blood treatment group. Coagulation index tests, Doppler ultrasound and mRNA sequencing were performed before and after anticoagulation therapy. There was no significant difference in postoperative DVT incidence between the two groups (23.1% versus 15.4%, P=0.694). D-dimer (D-D) and fibrinogen degradation product (FDP) showed significant reductions in both groups after anticoagulation treatments. We identified SLC4A1, PROS1, PRKAR2B and seven other genes as being differentially expressed during anticoagulation therapy in both groups. Genes correlated with coagulation indexes were also identified. Dragon's blood and LMWH showed similar effects on DVT and produced similar gene expression changes in patients undergoing hip fracture surgery, indicating that dragon's blood is a more convenient antithrombosis medicine (oral) than LMWH (hypodermic injection).

Elevated Serum Chloride Levels Contribute to a Poor Prognosis in Patients with IgA Nephropathy.

INTRODUCTION: The identification of reliable prognostic factors is a crucial requirement for patients with IgA nephropathy (IgAN). Here, we explored the relationship between serum chloride levels and prognosis in patients with IgAN. METHODS: We recruited all patients with primary IgAN, as diagnosed by renal biopsy, between 1st January 2015 and 1st April 2019. Patients were divided two groups (high chloride group and low chloride group) based on the best cut-off values from survival receiver operating characteristic (ROC) curves. The baseline clinicopathological characteristics of two groups were then compared. Cox proportional hazard models were used to determine the prognostic value of serum chloride levels in patients with IgAN. Finally, we screened reliable prognostic indicators and built a clinical prediction model and validated the performance of the model. RESULTS: Compared with patients in the high chloride group, patients in the low chloride group had significantly lower levels of 24-hour urinary total protein (24 h-UTP), serum creatinine (sCr), and higher levels of hemoglobin (Hb), albumin (all p < 0.05), and less proportion of Oxford classification grade E1 (endothelial cell proliferation) and T2 (renal tubule atrophy or renal interstitial fibrosis). Cox analysis revealed that serum chloride level ≥ 105.4 mmol/L was a significant and independent risk factor for prognosis in patients with IgAN (p < 0.05). Serum chloride, sCr, T, hypertension, and Hb were used to generate a predictive model for prognosis. Thec-indices of our predictive model were 0.80, 0.86, and 0.78, for 1, 2, and 3 years, respectively; Brier scores were 0.06, 0.09, and 0.16, respectively. CONCLUSIONS: A serum chloride level ≥ 105.4 mmol/l was identified as a significant and independent risk factor for the prognosis of patients with IgAN. A predictive prognosis model was generated using serum chloride, sCr, T, hypertension, and Hb; this model exhibited a good predictive effect.

The ZNF76 rs10947540 polymorphism associated with systemic lupus erythematosus risk in Chinese populations.

Systemic lupus erythematosus (SLE) is a typical autoimmune disease with a strong genetic disposition. Genetic studies have revealed that single-nucleotide polymorphisms (SNPs) in zinc finger protein (ZNF)-coding genes are associated with susceptibility to autoimmune diseases, including SLE. The objective of the current study was to evaluate the correlation between ZNF76 gene polymorphisms and SLE risk in Chinese populations. A total of 2801 individuals (1493 cases and 1308 controls) of Chinese Han origin were included in this two-stage genetic association study. The expression of ZNF76 was evaluated, and integrated bioinformatic analysis was also conducted. The results showed that 28 SNPs were associated with SLE susceptibility in the GWAS cohort, and the association of rs10947540 was successfully replicated in the independent replication cohort (Preplication = 1.60 × 10-2, OR 1.19, 95% CI 1.03-1.37). After meta-analysis, the association between rs10947540 and SLE was pronounced (Pmeta = 9.62 × 10-6, OR 1.29, 95% CI 1.15-1.44). Stratified analysis suggested that ZNF76 rs10947540 C carriers were more likely to develop relatively high levels of serum creatinine (Scr) than noncarriers (CC + CT vs. TT, p = 9.94 × 10-4). The bioinformatic analysis revealed that ZNF76 rs10947540 was annotated as an eQTL and that rs10947540 was correlated with decreased expression of ZNF76. Remarkably, significantly reduced expression of ZNF76 was confirmed by expression data from both our laboratory and an array-based expression database. Taken together, these results suggest that ZNF76 rs10947540 is a possible susceptibility factor associated with SLE susceptibility. The mechanism underlying the relationship between ZNF76 and SLE pathogenesis still requires further investigation.

Association of the PINX1 Variant rs6984094, Which Lengthens Telomeres, with Systemic Lupus Erythematosus Susceptibility in Chinese Populations.

A recent genome-wide association study (GWAS) of Asian ancestry reported that single nucleotide polymorphism (SNP) in TERT (telomerase reverse transcriptase) was associated with systemic lupus erythematosus (SLE). TERT has a critical role in maintaining the chromosomal stability and the length of telomere. Given that only a small portion of the genetic heritability of SLE has been explained so far, we aimed to identify novel loci in telomere-related genes responsible for SLE susceptibility in Chinese populations. We performed a comprehensive genetic association analysis of SLE with telomere-related genes. To identify functional significance, we analyzed the publicly available HaploReg v4.1 and RegulomeDB databases. Differential gene expression analysis was also performed using ArrayExpress. A novel signal of PINX1 rs6984094 was identified (P discovery = 4.13 × 10-2, OR = 0.58, 95% CI 0.35-0.98) and successfully replicated (P replication = 5.73 × 10-3, OR = 0.45, 95% CI 0.26-0.81). Multiple layers of functional analysis suggested that the PINX1 rs6984094 risk T allele exhibited increased nuclear protein binding. We also observed an increased expression of PINX1 mRNA in peripheral blood mononuclear cells from SLE patients compared with healthy controls. Overall, we observed a novel genetic association between PINX1 (encodes the PinX1 protein, an inhibitory telomerase enzyme that lengthens telomeres) and SLE susceptibility in Chinese populations.

Lupus susceptibility region containing CTLA4 rs17268364 functionally reduces CTLA4 expression by binding EWSR1 and correlates IFN-α signature.

BACKGROUND: Dysregulation of T cells mediated immune responses is a hallmark in the development of systemic lupus erythematosus (SLE). Recent genome wide association study (GWAS) revealed the genetic contribution of variants located in the cytotoxic T lymphocyte-associated protein-4 (CTLA4)-inducible T cell co-stimulator (ICOS) intergenic region to SLE susceptibility. Our aim is to find a functional variant in this region. METHODS: The genetic association results in the CTLA4-ICOS region from previous GWAS were adopted to select the potential variant which was further replicated in two independent cohorts (Henan cohort 2053 SLE patients and 1845 healthy controls, Beijing cohort 2303 SLE patients and 19,262 healthy). In order to explore the functional significance in SLE, bioinformatics with validation experiments (including electrophoretic mobility shift assay and luciferase reporter assay) and mRNA expression analysis were also performed. RESULTS: A variant located in the CTLA4-ICOS intergenic region, rs17268364, was associated with susceptibility to SLE patients in Chinese populations (risk allele, pmeta = 7.02×10-11, OR 1.19, 95%CI 1.13-1.26). The bioinformatics suggested that rs17268364 might affect the expression of CTLA4, not ICOS. The rs17268364 risk G allele containing sequence reduced the expression of the reporter gene by binding transcriptional repressor Ewing sarcoma breakpoint region 1 (EWSR1). Following genotype-mRNA expression, the analysis also showed the risk allele of rs17268364 was associated with low CTLA4 expression in lupus nephritis (LN) patients. Healthy individuals carrying rs17268364 risk G allele was significantly correlated with higher levels of IFN-α signature including increased lymphocyte antigen 6E (LY6E) (p=0.031), interferon-stimulated gene 15 (ISG15) (p=0.038), interferon regulatory factor 9 (IRF9) (p=0.028), and interferon regulatory factor 5 (IRF5) (p=0.040) mRNA expression. CONCLUSIONS: The present study confirmed the functional role of rs17268364 in the CTLA4-ICOS intergenic region that increased SLE susceptibility in the Chinese population.

The soluble VEGF receptor sFlt-1 contributes to endothelial dysfunction in IgA nephropathy.

Endothelial injury is a common manifestation in IgA nephropathy (IgAN). After the previous identification of the upregulated soluble fms-like tyrosine kinase-1 (sFlt-1) correlated with endothelial injury in IgAN, in the present study, we further explored the role of sFlt-1 in endothelial injury in IgAN. We enrolled 72 patients with IgAN and detected the sFlt-1 levels. The polymeric IgA1 (pIgA1) complexes were isolated from the pooled plasma samples of another 10 patients with IgAN. Apoptosis proteins were detected in cultured human umbilical vein endothelial cells (HUVECs) with the stimulation of recombinant sFlt-1 or the caspase-9 inhibitor Z-LEHD-FMK. We identified there were positive correlations between sFlt-1 and IgA-IgG complex as well as vWF levels in patients with IgAN. The sFlt-1 levels in HUVECs were significantly upregulated by pIgA1 complex derived from IgAN patients in a concentration-dependent manner. The proliferation ability of HUVECs was damaged when stimulated with sFlt-1 protein in a time- and dose- dependent manner. And the apoptosis rate was up-regulated significantly as the stimulation concentrations of sFlt-1 increased. We found sFlt-1 challenge could significantly increase the expression of vWF. In addition, sFlt-1 increased the levels of caspase-9, caspase-3, Bax and mitochondrial membrane potential; facilitated the release of cytochrome C from mitochondria to cytoplasma. In contrast, Z-LEHD-FMK attenuated high sFlt-1-induced HUVECs apoptosis. In conclusion, our study demonstrated that sFlt-1 expression was up-regulated by the challenge of pIgA1 complex derived from patients with IgAN. Furthermore, increased sFlt-1 facilitated human umbilical vein endothelial cells apoptosis via the mitochondrial-dependent pathway.

Single Nucleotide Polymorphisms in PPARD Associated with Systemic Lupus Erythematosus in Chinese Populations.

BACKGROUND: Systemic lupus erythematosus (SLE) is a multifactorial autoimmune disease characterized by apoptotic clearance deficiency provoking autoimmune responses and leading to multiple organ damage. PPAR-δ, encoded by the PPARD gene, was induced in macrophages promoting the timely disposal of apoptotic cells. Biological studies had provided solid foundation of PPARD involvement in SLE; it is worthwhile to further explore the genetic contribution of PPARD to SLE. METHODS: We performed a discovery-replication genetic association study. The discovery study was based on previous reported GWAS data. And the replication study was conducted in 1003 SLE patients and 815 healthy controls from Henan, Middle East of China. Further, we analyzed the eQTL effect to identify possible functional significance. RESULTS: In the genetic association analysis, we observed significant association between the risk C allele of rs4713853 (p = 0.03, OR 1.167, 95% CI 1.015-1.341) and increased SLE susceptibility. Moreover, individuals with the risk C allele were associated with lower expression of PPARD and DEF6. Our clinical analysis showed that SLE patients with the risk C allele of rs4713853 were more likely to present a higher proportion of anti-Sm antibody presence (CC+CT vs. TT, 20.0% vs. 14.2%, p = 0.039) and higher level of Scr (median inter quarter range CC+CT vs. TT, 56 48-71 vs. 54 46-64 µmol/L, p = 0.002). CONCLUSIONS: In conclusion, our study identified a novel association between PPARD rs4713853 and SLE susceptibility in Chinese populations. By integrating multiple layers of analysis, we suggested that PPARD might be a main candidate in the pathogenesis of SLE.

SCUBE3 Is Likely a Susceptibility Gene for Systemic Lupus Erythematosus for Chinese Populations.

BACKGROUND: Systemic lupus erythematosus (SLE) is a complex autoimmune disease with strong genetic disposition with more than 100 susceptibility genes identified until now. However, our knowledge on SLE genetic background is still limited. The present study was aimed at evaluating the role of single nucleotide polymorphisms (SNPs) in SCUBE3, a TGF-ß signaling activator, with SLE susceptibility in Chinese populations. METHODS: A total of 2801 individuals (490 cases and 493 controls from GWAS cohort and 1003 cases and 815 controls from our cohort) were enrolled, and SNPs located 10 kb up- and downstream of SCUBE3 (chr6:35182190-35218609) were included in the genetic association study. Multiple layers of bioinformatics were conducted, and the levels of SCUBE3 expression were confirmed. RESULTS: Of the 31 SNPs in SCUBE3 tested, 24 SNPs were significantly associated with SLE at p ≤ 0.05. The top locus was rs1888822 with p = 8.74∗10-6 in the discovery cohort and was confirmed by the replication cohort with p = 0.012. Additionally, the levels of SCUBE3 mRNA expression were significantly lower in patients with SLE comparing with healthy controls (p = 4.28∗10-4). Further expression data from ArrayExpress showed that the expression of SCUBE3 was also lower in CD3+ T cells and B cells from patients with SLE. CONCLUSIONS: Our research revealed that variants in SCUBE3, which encode SCUBE3 as a TGF-ß signaling activator, can be considered as a new genetic susceptibility factor for systemic lupus erythematosus. And the reduced mRNA expression of SCUBE3 was first reported in patients with SLE.