Urine macrophage migration inhibitory factor in pediatric systemic lupus erythematosus

Targeted urine proteomics in lupus nephritis - a meta-analysis

BACKGROUND

Proteomic approaches are central in biomarker discovery. While mass-spectrometry-based techniques are widely used, novel targeted proteomic platforms have enabled the high-throughput detection of low-abundance proteins in an affinity-based manner. Urine has gained growing attention as an ideal biofluid for monitoring renal disease including lupus nephritis (LN).

METHODS

Pubmed was screened for targeted proteomic studies of LN urine interrogating ≥1000 proteins. Data from the primary studies were combined and a meta-analysis was performed. Shared proteins elevated in active LN across studies were identified, and relevant pathways were elucidated using ingenuity pathway and gene ontology analysis. Urine proteomic data was cross-referenced against renal single-cell RNAseq data from LN kidneys.

RESULTS

Two high-throughput targeted proteomic platforms with capacity to interrogate ≥1000 proteins have been used to investigate LN urine. Twenty-three urine proteins were significantly elevated in both studies, including 10 chemokines, and proteins implicated in angiogenesis, and extracellular matrix turnover. Of these, Cathepsin S, CXCL10, FasL, ferritin, macrophage migration inhibitory factor (MIF), and resistin were also significantly elevated within LN kidneys.

CONCLUSION

Targeted urinary proteomics have uncovered multiple novel biomarkers for LN. Further validation in prospective cohorts and mechanistic studies are warranted to establish their clinical utility.

Assessment of serum macrophage migration inhibitory factor (MIF), adiponectin, and other adipokines as potential markers of proteinuria and renal dysfunction in lupus nephritis: a cross-sectional study

Background

To date, the association of serum macrophage migration inhibitory factor (MIF) and serum adipokines with lupus nephritis is controversial.

Objective

To assess the utility of serum MIF, leptin, adiponectin and resistin levels as markers of proteinuria and renal dysfunction in lupus nephritis.

Methods

Cross-sectional study including 196 systemic lupus erythematosus (SLE) patients and 52 healthy controls (HCs). Disease activity was assessed by Systemic Lupus Erythematosus Disease Activity Index (SLEDAI). Renal SLE involvement was investigated by renal-SLEDAI. MIF, adiponectin, leptin and resistin levels were quantified by ELISA. We assessed the correlations of quantitative variables by Spearman correlation (r_s). Multivariable linear regression adjusted the variables associated with the severity of proteinuria.

Results

SLE patients had higher MIF (p = 0.02) and adiponectin (p < 0.001) than HCs. Patients with renal SLE involvement (n = 43) had higher adiponectin (19.0 vs 13.3 μg/mL, p = 0.002) and resistin (10.7 vs 8.9 ng/mL, p = 0.01) than patients with non-renal SLE (n = 153). Proteinuria correlated with high adiponectin (r_s = 0.19, p < 0.009) and resistin (r_s = 0.26, p < 0.001). MIF (r_s = 0.27, p = 0.04). Resistin correlated with increased creatinine (r_s = 0.18, p = 0.02). High renal-SLEDAI correlated with adiponectin (r_s = 0.21, p = 0.004). Multiple linear regression showed that elevated adiponectin (p = 0.02), younger age (p = 0.04) and low MIF (p = 0.02) were associated with the severity of proteinuria. Low MIF and high adiponectin levels interacted to explain the association with the severity of proteinuria (R² = 0.41).

Conclusions

High adiponectin combined with low MIF concentrations int+eract to explain the severity of proteinuria in renal SLE. These findings highlight the relevance of adiponectin, resistin and MIF as markers of LN.

miR-152 Attenuates the Severity of Lupus Nephritis Through the Downregulation of Macrophage Migration Inhibitory Factor (MIF)-Induced Expression of COL1A1

Background: The role of miR-152 in lupus nephritis has not been elucidated. The aim of this study was to investigate the role of miR-152 in the pathogenesis of lupus nephritis (LN).

Methods: miR-152 expression was detected using RT-PCR in LN tissue and normal controls. The miR-152 expression was compared with clinical parameters such as 24 h urine protein excretion level, serum creatinine, and serum complement level and SLEDAI score. The function of miR-152 was examined using human renal proximal tubular epithelial cells (HRPTE). miR-152 mimics and inhibitors were transfected to HRPTEs to ascertain the effects of miR-152.

Results: miR-152 expression was downregulated in LN tissue. There was an inverse correlation between miR-152 expression in LN tissue and clinical parameters like 24 h urine protein excretion levels and serum creatinine, but not serum complement levels or SLEDAI. Further analysis showed that macrophage migration inhibitory factor (MIF) was a direct target of miR-152. Downregulation of MIF through complementary binding of miR-152 inhibited the renal expression of COL1A1.

Conclusion: miR-152 expression was tapered in LN tissue and miR-152 expression was inversely correlated with chronicity index (CI), serum creatinine and severity of proteinuria. miR-152 may attenuate the severity of LN through the downregulation of MIF-induced expression of COL1A1. These findings suggest that miR-152 may be a potential target for the treatment of LN.

Analysis of urinary macrophage migration inhibitory factor in systemic lupus erythematosus

Objective

To characterise the clinical relevance of urinary macrophage migration inhibitory factor (uMIF) concentrations in patients with systemic lupus erythematosus (SLE).

Methods

MIF, adjusted for urine creatinine, was quantified by ELISA in urine samples from 64 prospectively recruited patients with SLE. Serum MIF and urinary monocyte chemoattractant protein 1 (uMCP-1) were quantified by ELISA in a subset of patients (n = 39). Disease activity was assessed using the SLE Disease Activity Index-2000 (SLEDAI-2K) score.

Results

uMIF was detectable in all patients with SLE. uMIF was positively correlated with overall SLEDAI-2K, was significantly higher in patients with SLE with high disease activity (SLEDAI-2K≥10) compared with those with inactive disease (SLEDAI-2K<4), and this association remained significant after adjusting for ethnicity, flare and use of immunosuppressants. uMIF was also significantly higher in SLE patients with flare of disease, although not confirmed in multivariable analysis. No significant differences in uMIF levels were observed according to the presence of renal disease activity, as assessed by renal SLEDAI-2K or biopsy-confirmed lupus nephritis. In contrast, uMCP-1 was significantly higher in SLE patients with active renal disease. uMIF expression was not associated with irreversible organ damage accrual or glucocorticoid use.

Conclusions

These data suggest uMIF as a potential overall but not renal-specific SLE biomarker, whereas uMCP-1 is a renal-specific SLE biomarker.

Molecular mechanisms of glucocorticoid resistance in systemic lupus erythematosus: A review

The treatment of systemic lupus erythematosus (SLE) with glucocorticoids (GCs) is quite effective; however, GC resistance or insensitivity is a major barrier to the treatment of SLE. Therefore, it is necessary to identify the underlying mechanisms that lead to GC resistance. Much evidence shows that the mechanism of GC resistance is very complicated. GC receptor is involved in the main mechanism of GC resistance and was illustrated by a lot of literature. Therefore, this paper focuses on the GC resistance mechanisms of non-glucocorticoids receptor, including P-gp, MIF, TLR9, and Th17 cells. These molecular mechanisms may help diagnose GC resistance and provide an alternative treatment strategy to reverse GC resistance by blocking the underlying mechanisms.

Urinary CXCL-10/IP-10 and MCP-1 as markers to assess activity of lupus nephritis

Objective

IP-10 and MCP-1 are pro-inflammatory chemokines which are involved in the immunopathogenesis of lupus nephritis and may thus be useful biomarkers.

Methods

SLE patients fulfilling ACR 1997 criteria were included. SLEDAI was calculated and blood and urine samples collected. Active lupus was defined as SLEDAI ≥4. Active patients were divided into active renal (proteinuria ≥ 500 mg/day or active sediment in urine) and active non-renal lupus. Patients with active renal lupus were followed until the nephritis became inactive, when a second sample was collected. Serum and urinary levels of MCP-1 and IP-10 (pg/ml) were measured by ELISA. Urinary values were normalized for urinary spot creatinine (in mg/dL. Thus the values were expressed as pg/mg creatinine × 100 creatinine).

Results

A total of 136 patients with SLE including 78 active (46 active renal and 32 active non-renal) were included. Median age was 25 (10–55) years and SLE duration was 23 (six to 48) months. Both serum (data not shown) and urinary levels of MCP-1 (35.2 (12.7–71.7), 9.4 (4.4–17), p < 0.001) and IP-10 (9.5 (4.4–17.9), 3.9 (1.9–9.3), p < 0.001) were higher in active compared to inactive SLE. However, in active renal compared to active non-renal SLE, there was no difference in serum levels; only urinary levels of MCP-1 (46.2 (19.9–125), 12.7 (5.8–43.9), p < 0.001) and IP-10 (12.5 (5.6–22.7), 5.2 (2.3–12.2), p < 0.05) were higher. On longitudinal follow-up of active renal patients ( n = 24), there was a decrease in urinary levels of MCP-1 and IP-10 ( p = 0.005). On ROC analysis, urinary MCP-1 outperformed C4 and urinary IP-10, but was similar to dsDNA and C3 in differentiating active renal from non-renal SLE.

Conclusions

Urinary and serum IP-10 and MCP-1 are potentially useful markers of lupus activity; however, only the urinary levels are indicative of renal activity. However, on ROC analysis, they are not better than conventional markers.

Lupus nephritis: current update

Lupus nephritis is a major cause of morbidity and mortality in patients with systemic lupus erythematosus. The general consensus is that 60% of lupus patients will develop clinically relevant nephritis at some time in the course of their illness. Prompt recognition and treatment of renal disease is important, as early response to therapy is correlated with better outcome. The present review summarizes our current understanding of the pathogenic mechanisms underlying lupus nephritis and how the disease is currently diagnosed and treated.

Current and emerging strategies for the treatment and management of systemic lupus erythematosus based on molecular signatures of acute and chronic inflammation

Lupus is a chronic, systemic inflammatory condition in which eicosanoids, cytokines, nitric oxide (NO), a deranged immune system, and genetics play a significant role. Our studies revealed that an imbalance in the pro- and antioxidants and NO and an alteration in the metabolism of essential fatty acids exist in lupus. The current strategy of management includes administration of nonsteroidal anti-inflammatory drugs such as hydroxychloroquine and immunosuppressive drugs such as corticosteroids. Investigational drugs include the following: 1) belimumab, a fully human monoclonal antibody that specifically recognizes and inhibits the biological activity of B-lymphocyte stimulator, also known as B-cell-activation factor of the TNF family; 2) stem cell transplantation; 3) rituximab, a chimeric monoclonal antibody against CD20, which is primarily found on the surface of B-cells and can therefore destroy B-cells; and 4) IL-27, which has potent anti-inflammatory actions. Our studies showed that a regimen of corticosteroids and cyclophosphamide, and methods designed to enhance endothelial NO synthesis and augment antioxidant defenses, led to induction of long-lasting remission of the disease. These results suggest that methods designed to modulate molecular signatures of the disease process and suppress inflammation could be of significant benefit in lupus. Some of these strategies could be vagal nerve stimulation, glucose-insulin infusion, and administration of lipoxins, resolvins, protectins, and nitrolipids by themselves or their stable synthetic analogs that are known to suppress inflammation and help in the resolution and healing of the inflammation-induced damage. These strategies are likely to be useful not only in lupus but also in other conditions, such as rheumatoid arthritis, scleroderma, ischemia-reperfusion injury to the myocardium, ischemic heart disease, and sepsis.

Macrophage migration inhibitory factor (MIF): a promising biomarker

Macrophage migration inhibitory factor (MIF) is an immunoregulatory cytokine, the effect of which on arresting random immune cell movement was recognized several decades ago. Despite its historic name, MIF also has a direct chemokine-like function and promotes cell recruitment. Multiple clinical studies have indicated the utility of MIF as a biomarker for different diseases that have an inflammatory component; these include systemic infections and sepsis, autoimmune diseases, cancer, and metabolic disorders such as type 2 diabetes and obesity. The identification of functional promoter polymorphisms in the MIF gene (MIF) and their association with the susceptibility or severity of different diseases has not only served to validate MIF's role in disease development but also opened the possibility of using MIF genotype information to better predict risk and outcome. In this article, we review the clinical data of MIF and discuss its potential as a biomarker for different disease applications.

Biomarkers in lupus nephritis

Biomarkers have the potential to be useful tools for noninvasively evaluating and managing patients with lupus nephritis. Many candidate biomarkers have been identified, but they require validation in larger cohorts. It is likely that combinations or biomarker profiles, rather than individual markers, will emerge to help better predict the severity of inflammation, the extent of fibrosis, degree of drug responsiveness, and other variables. This approach has the potential to reduce the use of the renal biopsy, improve therapeutic efficacy, and limit toxicity. We predict algorithms based on genotype and biomarkers combined with clinical presentation will emerge to help guide physicians in management. Assays that show the most potential include serum erythrocyte bound complement C4d, interleukin 17, interleukin 23, interferon score/chemokine score ratio, and anti-C1q antibodies. Such urinary biomarkers as fractional excretion of endothelial-1, monocyte chemoattractant protein-1, vascular cell adhesion molecule-1, and TWEAK (tumor necrosis factor-like weak inducer of apoptosis) may also be useful but require validations.