Biomarker For Lupus Nephritis Research Articles

Proximity extension assay proteomics and renal single cell transcriptomics uncover novel urinary biomarkers for active lupus nephritis

ObjectiveTo identify urinary biomarkers that can distinguish active renal involvement in Lupus Nephritis (LN), a severe manifestation of systemic lupus erythematosus (SLE). MethodsUrine from 117 subjects, comprised of inactive SLE, active non-renal lupus, active LN, and healthy controls, were subjected to Proximity Extension Assay (PEA) based comprehensive proteomics followed by ELISA validation in an independent, ethnically diverse cohort. Proteomic data is also cross-referenced to renal transcriptomic data to elucidate cellular origins of biomarkers. ResultsSystems biology analyses revealed progressive activation of cytokine signaling, chemokine activity and coagulation pathways, with worsening renal disease. In addition to validating 30 previously reported biomarkers, this study uncovers several novel candidates. Following ELISA validation in an independent cohort of different ethnicity, the six most discriminatory biomarkers for active LN were urinary ICAM-2, FABP4, FASLG, IGFBP-2, SELE and TNFSF13B/BAFF, with ROC AUC ≥80%, with most correlating strongly with clinical disease activity. Transcriptomic analyses of LN kidneys mapped the likely origin of these proteins to intra-renal myeloid cells (CXCL16, IL-1RT2, TNFSF13B/BAFF), T/NK cells (FASLG), leukocytes (ICAM2) and endothelial cells (SELE). ConclusionIn addition to confirming the diagnostic potential of urine ALCAM, CD163, MCP1, SELL, ICAM1, VCAM1, NGAL and TWEAK for active LN, this study adds urine ICAM-2, FABP4, FASLG, IGFBP-2, SELE, and TNFSF13B/BAFF as additional markers that warrant systematic validation in larger cross-sectional and longitudinal cohorts.

Circulating exosomal microRNAs as biomarkers of lupus nephritis.

Disruption in the delicate symphony of genes, microRNA (miRNA), or protein expression can result in the dysregulation of the immune system, leading to the devastating consequences such as lupus nephritis (LN). The capacity of exosomes to transport miRNAs between cells and modify the phenotype of recipient cells implies their involvement in persistent kidney inflammation. This study unveils identifying two previously undiscovered exosomal miRNAs in the serum of LN patients, offering potential solutions to the current challenges in LN diagnosis and management. Initially, we used a reagent-based kit to isolate serum exosomes from patients with Systemic lupus erythematosus (SLE) and used Trizol method for total RNA extraction. Subsequently, we employed small RNA sequencing to screen for differential expression profiles of exosomal small RNAs. The RT-qPCR method was used to individually validate samples in both the screening and validation cohorts, enabling the identification of candidate small RNAs; specific to LN. We assessed the diagnostic potency using receiver operating characteristic (ROC) curve, and explored the biological roles of miRNAs using Gene Ontology (GO) and Kyoto Encyclopedia of Genes and Genomes (KEGG) analyses. Compared to SLE patients without LN, SLE patients accompanied by LN exhibited significantly spiked levels of exosomal hsa-miR-4796-5p and hsa-miR-7974. The duo of miRNAs, hsa-miR-4796-5p and hsa-miR-7974, exhibited promising potential as biomarkers for diagnosing LN, with an AUC exceeding 0.8. Correlation analysis revealed a strong positive association between these miRNAs and proteinuria, as well as the SLE Disease Activity Index (SLEDAI) score. Moreover, the levels of two miRNAs in LN patients were significantly elevated in comparison to other autoimmune nephritis conditions, such as immunoglobulin A nephropathy (IgAN) and diabetic nephropathy (DN). Furthermore, the bioinformatics analysis indicated that this miRNAs duo can play a pivotal role in the regulation of immune processes by modulating signal pathways, such as the mTOR and PI3K-Akt signaling pathway. This study provides a new ground that serum exosomal miRNAs can effectively identify and predict LN in SLE patients.

Evaluation of Serum Visfatin as a Biomarker of Lupus Nephritis in Egyptian Patients with Systemic Lupus Erythematosus.

One of the most significant consequences of systemic lupus erythematosus (SLE) is lupus nephritis (LN). Visfatin, an adipokine that is significantly expressed in visceral fat and is a marker of endothelial dysfunction in chronic kidney disease, has multiple proinflammatory actions. We aimed to evaluate the state of serum visfatin in SLE patients and to detect its possible correlation with the disease's activity and effects on the kidney affection. Fifty patients with active LN, 50 patients with inactive lupus, and 50 healthy people had their serum visfatin levels tested. Chemical and immunological markers of SLE and LN were measured. The SLE Disease Activity Index (SLEDAI) was used to measure the disease's activity. Renal biopsies from the LN subgroup were collected and classified using the modified classification of the World Health Organization. The serum visfatin of patients with active LN was significantly greater than that of inactive lupus patients and the healthy controls (20.56 ± 1.07 ng/mL, 16.77 ± 1.02 ng/mL, and 9.96 ± 1.46 ng/mL, P <0.001). SLEDAI and serum visfatin levels were shown to be significantly correlated (P = 0.000057). Serum visfatin levels were likewise significantly correlated with the index of histological activity in the active group (P <0.00001). Serum visfatin was raised in individuals with active LN and was related to the SLEDAI and disease severity scores. Serum visfatin could be utilized as a noninvasive biomarker for evaluating the severity of LN and risk stratification of the risk.

Metabolic Markers and Association of Biological Sex in Lupus Nephritis.

Lupus nephritis (LN) is a serious complication for many patients who develop systemic lupus erythematosus, which primarily afflicts women. Our studies to identify biomarkers and the pathogenic mechanisms underlying LN will provide a better understanding of disease progression and sex bias, and lead to identification of additional potential therapeutic targets. The glycosphingolipid lactosylceramide (LacCer) and N-linked glycosylated proteins (N-glycans) were measured in urine and serum collected from LN and healthy control (HC) subjects (10 females and 10 males in each group). The sera from the LN and HC subjects were used to stimulate cytokine secretion and intracellular Ca2+ flux in female- and male-derived primary human renal mesangial cells (hRMCs). Significant differences were observed in the urine of LN patients compared to HCs. All major LacCers species were significantly elevated and differences between LN and HC were more pronounced in males. 72 individual N-glycans were altered in LN compared to HC and three N-glycans were significantly different between the sexes. In hRMCs, Ca2+ flux, but not cytokine secretion, was higher in response to LN sera compared to HC sera. Ca2+ flux, cytokine secretion, and glycosphingolipid levels were significantly higher in female-derived compared to male-derived hRMCs. Relative abundance of some LacCers and hexosylceramides were higher in female-derived compared to male-derived hRMCs. Urine LacCers and N-glycome could serve as definitive LN biomarkers and likely reflect renal disease activity. Despite higher sensitivity of female hRMCs, males may experience greater increases in LacCers, which may underscore worse disease in males. Elevated glycosphingolipid metabolism may poise renal cells to be more sensitive to external stimuli.

Endothelial cell activation and glycocalyx shedding - potential as biomarkers in patients with lupus nephritis.

Lupus nephritis (LN) is a common and severe manifestation of systemic lupus erythematosus and an important cause of acute and chronic kidney injury. Early diagnosis of LN and preventing relapses are key to preserving renal reserve. However, due to the complexity and heterogeneity of the disease, clinical management remains challenging. Kidney biopsy remains the gold standard for confirming the diagnosis of LN and subsequent assessment of kidney histopathology, but it is invasive and cannot be repeated frequently. Current clinical indicators of kidney function such as proteinuria and serum creatinine level are non-specific and do not accurately reflect histopathological changes, while anti-dsDNA antibody and C3 levels reflect immunological status but not kidney injury. Identification of novel and specific biomarkers for LN is prerequisite to improve management. Renal function deterioration is associated with changes in the endothelial glycocalyx, a delicate gel-like layer located at the interface between the endothelium and bloodstream. Inflammation induces endothelial cell activation and shedding of glycocalyx constituents into the circulation. This review discusses the potential role of soluble glycocalyx components as biomarkers of active LN, especially in patients in whom conventional serological and biochemical markers do not appear helpful.

Microvascular C5b-9 deposition in non-lesional skin in patients with SLE and its correlation with active lupus nephritis: a prospective observational study

ObjectiveTissue damage in lupus nephritis (LN) is mediated by activation of the classical complement pathway. Complement-mediated upregulation of endothelial cell adhesion molecules is seen in dermal blood vessels of non-lesional...

Urine SERPINC1/ORM1 as biomarkers for early detection of lupus nephritis in MRL-lpr mice.

To evaluate the usefulness of urine SERPINC1 and ORM1 as biomarkers for early detection of lupus nephritis (LN). Using proteomics, we screened for potential urine biomarkers that differentiate LN from systemic lupus erythematosus (SLE) patients without nephritis. In addition, urine levels of target biomarkers were measured by ELISA in 13- and 23-week-old MRL-lpr (murine model for LN) and MRL/MpJ mice. Histological analysis was also performed on the kidneys of 23-week-old mice. Urine SERPINC1 and ORM1 were elevated in SLE patients with newly diagnosed LN compared with SLE patients without LN (SERPINC1, AUC=.892, P<.001; ORM1, AUC=.886, P<.001). Levels of urine SERPINC1 and ORM1 were also significantly higher in MRL-lpr mice than in MRL/MpJ mice at 13 and 23 weeks (SERPINC1: p<.01 and p<.001 at 13 and 23 weeks, respectively; ORM1: p<.01 at 13 and 23 weeks). In contrast, a significant difference in urine albumin between the two groups was only observed at 23 weeks (p<.001) not at 13 weeks (p=.83). Regarding the kidney pathology of MPL-lpr mice, urine ORM1 and urine albumin, but not urine SERPINC1, were positively correlated with the activity index (ORM1, rho =.879, p<.001; albumin, rho =.807, p=.003) and chronicity index (ORM1, rho =.947, p<.001; albumin, rho =.869, p<.001). We propose that urine SERPINC1 and ORM1 are novel biomarkers for early LN.

Urine L-selectin reflects clinical and histological renal disease activity and treatment response in lupus nephritis across multi-ethnicity.

There is an urgent need for novel biomarkers in lupus nephritis (LN). We report a non-invasive urinary biomarker, L-selectin, in two independent multi-ethnic cohorts. uL-selectin was tested cross-sectionally in a Chinese cohort (n=255) and a US cohort (n=219) of SLE patients and controls using ELISA. A longitudinal cohort includes 20 active Chinese LN patients. uL-selectin was significantly increased in active LN patients compared to active non-renal SLE, inactive LN, inactive non-renal SLE, chronic kidney disease patients, and healthy controls. uL-selectin positively correlated with global and renal disease activities as well as histological activity index and chronicity index (CI). Low uL-selectin was an independent predictor for high CI. During follow-up, uL-selectin levels decreased significantly in the complete renal remission group. uL-selectin is a novel biomarker of disease activity and renal histopathology in LN across multiple ethnicities. It also reflects treatment response in LN patients during follow up.

Urinary neutrophil gelatinase-associated lipocalin (uNGAL) and kidney injury molecule-1 (uKIM-1) as markers of active lupus nephritis

Background and objectivesDespite much research about lupus nephritis, none of the urinary biomarkers has been proven to be truly reflecting lupus nephritis activity, response to treatment, or prognosis. We aimed to study urinary biomarkers in lupus nephritis and test their relation to kidney damage.Patients and methodsForty patients with systemic lupus erythematosus (SLE) were divided into two graoups: (1) lupus nephritis group with biopsy-proven proliferative lupus nephritis (classes III and IV) and who did not receive immunosuppressive drugs within the preceding 3 months except for glucocorticoids and (2) lupus non-nephritis group with SLE patients without any renal manifestation. We assessed disease activity by the SLE disease activity index. uNGAL, uKim-1, uNGAL to urinary creatinine excretion (mg/dl), and uKim-1 to urinary creatinine excretion were measured in random spot urine samples at the time of renal biopsy and 6 months after the induction therapy.ResultsThe LN group before treatment showed higher levels of uNGAL and uKIM-1 (P-value < 0.001). ROC analysis showed that uNGAL at level of > 59 has a 95 % sensitivity, a 100 % specificity, and an AUC = 0.996 in the ability to diagnose LN. While the uKIM-1 ROC showed that at level of > 1.6, it has an 85 % sensitivity, an 80 % specificity, and an AUC = 0.919. uNGAL and uKIM levels were significantly lower after treatment (P-value < 0.001). No significant correlations were found between urinary markers before and after treatment with other clinical, inflammatory, and serological markers of lupus nephritis.ConclusionuNGAL, uKIM, uNGAL/Creat ratio, and uKIM/Creat ratio can be used as a predictor and a marker of disease activity for lupus nephritis.Key Points• Renal biopsy is the current standard for diagnosis of lupus nephritis and none of the urinary biomarkers has been fully concluded to have a diagnostic power to reflect the activity or the response to treatment.• However, based on the finding of the current study, uNGAL, uKIM, uNGAL/Creat ratio, and uKIM/Creat ratio showed significant diagnostic performance and were powerful indices of renal involvement in systemic lupus patients and as markers of disease activity.

Urinary Long Non-Coding RNA Levels as Biomarkers of Lupus Nephritis.

Emerging evidence suggests that long non-coding RNA (lncRNA) plays important roles in the regulation of gene expression. We determine the role of using urinary lncRNA as a non-invasive biomarker for lupus nephritis. We studied three cohorts of lupus nephritis patients (31, 78, and 12 patients, respectively) and controls (6, 7, and 24 subjects, respectively). The urinary sediment levels of specific lncRNA targets were studied using real-time quantitative polymerase chain reactions. The severity of proteinuria inversely correlated with urinary maternally expressed gene 3 (MEG3) (r = -0.423, p = 0.018) and ANRIL levels (r = -0.483, p = 0.008). Urinary MEG3 level also inversely correlated with the SLEDAI score (r = -0.383, p = 0.034). Urinary cancer susceptibility candidate 2 (CASC2) levels were significantly different between histological classes of nephritis (p = 0.026) and patients with pure class V nephritis probably had the highest levels, while urinary metastasis-associated lung carcinoma transcript 1 (MALAT1) level significantly correlated with the histological activity index (r = -0.321, p = 0.004). Urinary taurine-upregulated gene 1 (TUG1) level was significantly lower in pure class V lupus nephritis than primary membranous nephropathy (p = 0.003) and minimal change nephropathy (p = 0.04), and urinary TUG1 level correlated with eGFR in class V lupus nephritis (r = 0.706, p = 0.01). We identified certain urinary lncRNA targets that may help the identification of lupus nephritis and predict the histological class of nephritis. Our findings indicate that urinary lncRNA levels may be developed as biomarkers for lupus nephritis.

V-Set Immunoglobulin Domain-Containing Protein 4 as a Novel Serum Biomarker of Lupus Nephritis and Renal Pathology Activity.

To discover novel serum biomarkers that have diagnostic or predictive value in lupus nephritis (LN). Using a quantitative protein microarray, we screened for high-abundant proteome expression in the serum of patients with LN compared to healthy controls. Top candidates from this screening were validated using a larger cohort of patients with LN compared to a disease control cohort (subjects with other chronic kidney diseases) and a healthy control cohort. Promising markers were then selected using a machine-learning model and further validated with a larger patient cohort. The corresponding autoantibodies and immune complexes containing these proteins were also examined. In total, 13 proteins were found to be significantly elevated in LN patient serum in the screening, among which 8 proteins were validated by enzyme-linked immunosorbent assay using 81 serum samples from LN patients and control subjects. Three serum markers with LN diagnostic potential were identified using feature importance analysis and further validated using 155 serum samples from LN patients and control subjects. V-set immunoglobulin domain-containing protein 4 (VSIG4) appeared to be the most promising marker in distinguishing LN from healthy controls, with an area under the curve of 0.93. VSIG4 could also discriminate active LN from inactive LN. Furthermore, serum VSIG4 levels were positively correlated with all of the following clinical parameters: the Systemic Lupus Erythematosus Disease Activity Index (SLEDAI) score (Spearman's rank correlation rs = 0.42, P < 0.001), the renal domain score of the SLEDAI (rs = 0.46, P < 0.001), the urinary protein-to-creatinine ratio (rs = 0.56, P < 0.001), and the serum creatinine level (rs = 0.41, P < 0.001). Importantly, we found that serum VSIG4 levels tracked with LN disease activity longitudinally, and that serum VSIG4 levels reflected the renal pathology activity index (AI), particularly the AI components of crescent formation and hyaline deposits. VSIG4 may be a promising novel serum biomarker and therapeutic target in patients with LN.

#3252 PRESEPSIN AS A POTENTIAL BIOMARKER FOR RENAL INVOLVEMENT IN PATIENTS WITH SYSTEMIC LUPUS ERYTHEMATOSUS

Abstract Background and Aims Presepsin is a soluble CD14 subtype known as a sepsis biomarker. Recently, it has been reported to correlate with kidney function decline in elderly patients with chronic kidney disease and to predict acute kidney injury in patients with sepsis. However, the potential role of presepsin in systemic lupus erythematosus (SLE) with kidney involvement is still unclear. This study aimed to evaluate the relationship between serum presepsin level and SLE disease activity and laboratory parameters and to validate presepsin as a biomarker for lupus nephritis (LN). Method This cross-sectional study included 78 SLE patients aged 38.9±12.8 years. Among them, there were 68 (87.2%) women, 36 (46.2%) patients with LN, and 42 (53.8%) patients without LN. LN was diagnosed by renal biopsy and/or according to the renal SLE disease activity index (SLEDAI) criteria. Patients with infections were not included in the study. Serum presepsin level was determined by ELISA. The diagnostic value of presepsin level for the detection of LN was assessed by receiver-operating characteristic curves (ROC), the area under the curve (AUC), and 95% confidence intervals (CI). Spearman and Pearson correlation tests were performed to evaluate the relationships between presepsin level and SLEDAI score, serum complement concentrations, anti-double-stranded DNA antibodies (anti-dsDNA), inflammatory markers, urinary protein, and estimated glomerular filtration rate (eGFR) with CKD-EPI. Results The median serum presepsin level was significantly higher in patients with LN than in those without kidney damage [145 (110-197) pg/ml vs 102 (82-146) pg/ml, p = 0.011]. The ROC analysis found that the most appropriate cut-off point for presepsin concentration as a biomarker for LN in LSE patients was 106 pg/ml with a sensitivity of 81.8% (95% CI 64.5-93.0), and specificity of 54.3% (95% CI 36.6-71.2). The AUC was 0.714 (95% CI 0.592-0.837) with a positive predictive value of 62.8% (95% CI 46.7-77.0), and a negative predictive value of 76.0% (95% CI 54.9-90.6) (Fig. 1). The mean value of eGFR was 83.8±27.0 ml/min/1.73 m2 in the LN group and 94.1±18.0 ml/min/1.73 m2 in the non-LN group (p = 0.112). A significant negative correlation was observed between presepsin levels and eGFR in LN patients (Fig. 2). Moreover, presepsin levels in the LN group significantly correlated with SLEDAI score (r = 0.372, p = 0.036), anti-dsDNA titer (r = 0.363, p = 0.04) and severity of proteinuria (r = 0.630, p&amp;lt;0.01). No such associations were found in SLE patients without kidney involvement. Presepsin concentration did not correlate with C3, C4, C-reactive protein, erythrocyte sedimentation rate, and procalcitonin levels in both groups. Conclusion Serum presepsin may be considered a potential biomarker for the detection of kidney damage in patients with SLE. Further studies focusing on the clinical and pathological associations of presepsin in LN would be of interest.

Plasma soluble tumor necrosis factor receptor I as a biomarker of lupus nephritis and disease activity in systemic lupus erythematosus patients

Objectives The goal of our study was to evaluate the potential role of sTNF-RI as a biomarker of renal involvement in SLE patients and active SLE. Methods The study sample consisted of two cohorts. The discovery cohort included 16 SLE patients without renal involvement (non-LN), 60 lupus nephritis (LN) patients and 21 healthy controls (HCs) and the replication cohort included 18 SLE non-LN patients, 116 LN patients and 36 HCs. Results The sTNF-RI levels differed significantly in the discovery cohort. The plasma sTNF-RI levels were higher in LN patients than in non-LN patients (p = .009) and HCs (p = 4 × 10−6). Plasma sTNF-RI levels were significantly higher in non-LN patients than in HCs (p = .03). The finding was confirmed in independent replication cohort (LNs vs. non-LN, p = 4.053 × 10−7; LNs vs. HCs, p = 2.395 × 10−18; non-LN vs. HCs, p = 2.51 × 10−4). The plasma sTNF-RI levels were associated with disease activity, renal function in SLE patients and urine protein in LN patients. The multivariate analysis revealed that high sTNF-RI was an independent risk factor for renal involvement. The multivariate logistic regression results suggested that high TNF-RI, high systolic blood pressure, high serum creatinine, low C4 and positive anti-dsDNA were independent risks of active SLE patients. A nomogram was constructed based on the results of multivariate logistic regression analysis and it was practical in predicting the risk of the active SLE patients. Immunohistochemistry suggested that the expression of TNF-RI in the kidney was increased. Conclusions Plasma sTNF-RI might be a good biomarker of renal involvement and disease activity in SLE patients.

Searching for a prognostic index in lupus nephritis

BackgroundCurrently we do not have an ideal biomarker in lupus nephritis (LN) that should help us to identify those patients with SLE at risk of developing LN or to determine those patients at risk of renal progression. We aimed to evaluate the development of a prognostic index for LN, through the evaluation of clinical, analytical and histological factors used in a cohort of lupus. We have proposed to determine which factors, 6 months after the diagnosis of LN, could help us to define which patients will have a worse evolution of the disease and may be, more aggressive treatment and closer follow-up.MethodsA retrospective study to identify prognostic factors was carried out. We have included patients over 18 years of age with a clinical diagnosis of systemic lupus erythematosus (SLE) and kidney involvement confirmed by biopsy, who are followed up in our centre during the last 20 years. A multi-step statistical approach will be used in order to obtain a limited set of parameters, optimally selected and weighted, that show a satisfactory ability to discriminate between patients with different levels of prognosis.ResultsWe analysed 92 patients with LN, although only 73 have been able to be classified according to whether or not they have presented poor renal evolution. The age of onset (44 vs. 32; p = 0.024), the value of serum creatinine (1.41 vs. 1.04; p = 0.041), greater frequency of thrombocytopenia (30 vs. 7%; p = 0.038), higher score in the renal chronicity index (2.47 vs. 1.04; p = 0.015), proliferative histological type (100%) and higher frequency of interstitial fibrosis (67 vs. 32%; p = 0.017) and tubular atrophy (67 vs. 32%; p = 0.018) was observed between two groups. The multivariate analysis allowed us to select the best predictive model for poor outcome at 6 months based on different adjustment and discrimination parameters.ConclusionWe have developed a prognostic index of poor renal evolution in patients with LN that combines demographic, clinical, analytical and histopathological factors, easy to use in routine clinical practice and that could be an effective tool in the early detection and management.

Insulin-like growth factor binding protein-2 as a biomarker for lupus nephritis.

Lupus nephritis (LN) is a serious manifestation of systemic lupus erythematosus (SLE). The aim of this study was to identify serum insulin-like growth factor binding protein-2 (IGFBP-2) as a novel non-invasive biomarker for clinical disease and renal pathology in pediatric LN. A cross-sectional study on 93 newly diagnosed LN children who were biopsy-proven, 35 SLE children with no renal involvement as disease controls, and 30 healthy controls (HC) with age and gender-matched. All children were ELISA tested for serum IGFBP-2 levels. Clinical, laboratory, histopathological features of LN patients were collected. Compared to SLE or HC, serum IGFBP-2 levels were significantly elevated in LN patients. Serum IGFBP-2 could distinguish LN patients from two others (AUC = 0.937, p < 0.001 for LN vs. HC; 0.897, p < 0.0001 for LN vs. SLE). In ROC analysis, IGFBP-2 had a higher ability to differentiate between LN and SLE than anti-dsDNA with AUC values of 0.895 and 0.643, respectively. LN children with systemic lupus erythematosus disease activity index (SLEDAI) in high activity had significantly higher IGFBP-2 concentration than the others with SLEDAI in moderate activity. Serum IGFBP-2 correlated with albuminemia levels (r = 0.415, p < 0.001), urine protein-to-creatinine levels (r = 0.316, p = 0.002), estimated glomerular filtration rate (r = 0.438, p < 0.001), complement C3 (r = 0.333, p = 0.001). More importantly, serum IGFBP-2 correlated with the activity index of renal pathology (r = 0.312, p = 0.007, n = 75). Serum IGFBP-2 is a promising biomarker for pediatric lupus nephritis, reflective of disease activity and activity index in renal patients.

Evaluation of Urinary Ceruloplasmin as a Novel Biomarker for Lupus Nephritis

Evaluation of Urinary Ceruloplasmin as a Novel Biomarker for Lupus Nephritis

Candidate MicroRNA Biomarkers in Lupus Nephritis: A Meta-analysis of Profiling Studies in Kidney, Blood and Urine Samples.

Lupus nephritis (LN) is a kidney disease caused by systemic lupus erythematosus in which kidneys are attacked by the immune system. So far, various investigations have reported altered miRNA expression profiles in LN patients and different miRNAs have been introduced as biomarkers and/or therapeutic targets in LN. The aim of this study was to introduce a consensus panel of potential miRNA biomarkers by performing a meta-analysis of miRNA profiles in the LN patients. A comprehensive literature review approach was performed to find LN-related miRNA expression profiles in renal tissues, blood, and urine samples. After selecting the eligible studies and performing the data extraction, meta-analysis was done based on the vote-counting rank strategy as well as meta-analysis of p-values. The meta-miRNAs and their related genes were subjected to functional enrichment analyses and network construction. The results of the meta-analysis of 41 studies were three lists of consensus miRNAs with altered expression profiles in the various tissue samples of LN patients (meta-analysis of p-values < 0.05). Of the 13 studies on kidney tissue, the meta-miRNAs were let-7a, miR-198, let-7e, miR-145, and miR-26a. In addition, meta-miRNAs of miR-199a, miR-21, miR-423, miR-1260b, miR-589, miR-150, miR-155, miR-146a, and miR-183 from 21 studies on blood samples, and miR-146a, miR-204, miR-30c, miR-3201, and miR-1273e from 11 studies on urine samples can be considered as non-invasive biomarker panels for LN. Functional enrichment analysis on the meta-miRNA lists confirmed the involvement of their target genes in nephropathy-related signaling pathways. Using a meta-analytical approach, our study proposes three meta-miRNA panels that could be the target of further research to assess their potential as therapeutic targets/biomarkers in LN disease.

Predicting diagnostic gene expression profiles associated with immune infiltration in patients with lupus nephritis.

To identify potential diagnostic markers of lupus nephritis (LN) based on bioinformatics and machine learning and to explore the significance of immune cell infiltration in this pathology. Seven LN gene expression datasets were downloaded from the GEO database, and the larger sample size was used as the training group to obtain differential genes (DEGs) between LN and healthy controls, and to perform gene function, disease ontology (DO), and gene set enrichment analyses (GSEA). Two machine learning algorithms, least absolute shrinkage and selection operator (LASSO) and support vector machine-recursive feature elimination (SVM-RFE), were applied to identify candidate biomarkers. The diagnostic value of LN diagnostic gene biomarkers was further evaluated in the area under the ROC curve observed in the validation dataset. CIBERSORT was used to analyze 22 immune cell fractions from LN patients and to analyze their correlation with diagnostic markers. Thirty and twenty-one DEGs were screened in kidney tissue and peripheral blood, respectively. Both of which covered macrophages and interferons. The disease enrichment analysis of DEGs in kidney tissues showed that they were mainly involved in immune and renal diseases, and in peripheral blood it was mainly enriched in cardiovascular system, bone marrow, and oral cavity. The machine learning algorithm combined with external dataset validation revealed that C1QA(AUC = 0.741), C1QB(AUC = 0.758), MX1(AUC = 0.865), RORC(AUC = 0.911), CD177(AUC = 0.855), DEFA4(AUC= 0.843)and HERC5(AUC = 0.880) had high diagnostic value and could be used as diagnostic biomarkers of LN. Compared to controls, pathways such as cell adhesion molecule cam, and systemic lupus erythematosus were activated in kidney tissues; cell cycle, cytoplasmic DNA sensing pathways, NOD-like receptor signaling pathways, proteasome, and RIG-1-like receptors were activated in peripheral blood. Immune cell infiltration analysis showed that diagnostic markers in kidney tissue were associated with T cells CD8 and Dendritic cells resting, and in blood were associated with T cells CD4 memory resting, suggesting that CD4 T cells, CD8 T cells and dendritic cells are closely related to the development and progression of LN. C1QA, C1QB, MX1, RORC, CD177, DEFA4 and HERC5 could be used as new candidate molecular markers for LN. It may provide new insights into the diagnosis and molecular treatment of LN in the future.

Potential role of circulating miRNA-146a and serum kallikrein 1 as biomarkers of renal disease in biopsy-proven lupus nephritis patients

Aim of the workTo evaluate the performance of circulating miR-146a and serum kallikrein1 (KLK1) as biomarkers for detecting disease activity and distinguishing histopathological changes associated with lupus nephritis (LN). Patients and methods90 systemic lupus erythematosus (SLE) patients (44 with active non-renal disease and 46 with LN) were examined for relative expression levels of circulating miR-146a, assessed by reverse transcription quantitative real-time PCR (RT-qPCR) and serum KLK1 levels, measured by ELISA. SLE disease activity was assessed using SLEDAI-2 k. Receiver operating characteristic curve was employed to examine the diagnostic performance of both biomarkers and established conventional laboratory parameters of renal function with specific renal histologic features seen in LN. As well, 40 apparently healthy control subjects were enrolled. ResultsCirculating miR-146a levels were significantly lower (p < 0.01), while serum KLK1 levels were significantly higher (p < 0.01) in active LN patients compared to active non-renal and controls. miR-146a levels negatively correlated with serum creatinine, Albumin/Creatinine and SLEDAI-2 k (p ≤ 0.01), while serum KLK1 significantly correlated with serum creatinine, Albumin/Creatinine and C3 (p ≤ 0.05) and inversely with miR-146a (p = 0.002). Both circulating miR-146a and KLK1 revealed an outstanding performance in predicting renal activity among SLE patients with an AUC of 0.949 and 0.947 respectively. In active LN patients, KLK1 and miR-146a exhibited good ability in differentiating proliferative from non-proliferative LN (AUC 0.73, 0.65 respectively), and in predicting biopsy activity index ≥7, surpassing conventional disease measures. ConclusionCirculating miR-146a and serum KLK1 are potential biomarkers for LN that could compete with invasive renal biopsy. Independent validation is warranted.

Validity of immunoglobulin-binding protein 1 as a biomarker for lupus nephritis.

Lupus nephritis (LN) is a major issue that adds a burden on patients with systemic lupus erythematosus (SLE). Immunoglobulin-binding protein 1 (IGBP1) is identified as a phosphoprotein that has been recently reported to be linked to the B-cell receptor complex and regulates differentiation, proliferation, apoptosis, and tolerance of B cells. Its diagnostic and/or prognostic role in LN has been highlighted only recently. This study aims to evaluate the relation between serum IGBP1 and SLE disease activity and/or renal activity and to investigate the validity of IGBP1 as a biomarker for LN. 96 participants were enrolled and divided into three groups: nephritis, nonnephritis, and control groups. The patients with SLE were diagnosed according to the Systemic Lupus International Collaborating Clinics classification (SLICC) criteria. The serum IGBP1 level was assayed using an enzyme-linked immunosorbent assay (ELISA). Assessments were conducted using the Systemic Lupus Erythematosus Disease Activity Index 2000 (SLEDAI-2k) and renal biopsy for LN patients. The nephritis and nonnephritis groups had higher IGBP1 levels than the controls; the nephritis group had the highest serum IGBP1 levels (p < .001). Significant correlations were found between IGBP1 levels and proteinuria (r = 0.568, p = .001) and renal SLEDAI (r = 0.475, p = .006) in the nephritis group; on the other hand, the correlation of serum IGBP1 levels with SLEDAI-2K was non-significant for both groups (nephritis and nonnephritis groups). The IGBP1 levels were significantly different among histopathologic classes (p < .001), with class V showing the highest level. Moreover, it showed a significant positive correlation with the pathologic activity index. Compared with renal SLEDAI for identifying active renal affection in patients with SLE, the serum IGBP1 level with a cut-off value of 547.45ng/mL is a valid biomarker for detecting active nephritis with 93.8% sensitivity and 96.9% specificity. The serum IGBP1 levels were high in patients with LN and were positively correlated with the pathologic activity index. The serum IGBP1 level of 547.45ng/mL is a valid biomarker for detecting active nephritis. Thus, we recommend that clinicians monitor the serum IGBP1 level of patients with SLE to detect LN.