Elevated macrophage migration inhibitory factor (MIF) levels in the urine of patients with focal glomerular sclerosis

Elevated urinary monocyte chemoattractant protein-1 levels in children with Henoch-Schonlein purpura nephritis

BACKGROUND

Chemokine monocyte chemoattractant protein-1 (MCP-1) has been proved as a potential urinary biomarker in nephropathies. The aim of this study was to investigate the urinary monocyte chemoattractant protein-1 (MCP-1) levels and clinical significance in Henoch-Schonlein purpura (HSP) children with and without nephritis and determine the association of MCP-1 with proteinuria.

METHODS

A total of 261 HSP children-with or without nephritis-and 84 healthy control children were enrolled in this study. Of these, 126 HSP nephritis (HSPN) children were subdivided into three groups according to total urine protein in 24 h (TUP): Group A, mild proteinuria group with TUP <25 mg/kg; Group B, moderate proteinuria group with TUP ≥25 mg/kg and <50 mg/kg; Group C, severe proteinuria group with TUP ≥50 mg/kg. Urinary MCP-1 levels were determined by ELISA. Levels of serum creatinine (Cr), blood urea nitrogen (BUN), urinary α₁-micro globulin (α₁-MG), micro-albumin (mAlb), immunoglobulin G (IgG), transferrin (TRF) and TUP were performed to determine their associations with MCP-1.

RESULTS

Urinary MCP-1 was significantly higher in HSPN group in comparison with HSP group and controls (P < 0.05), but no significant difference was found between the HSP group and the healthy group (P > 0.05). The levels of urinary MCP-1 increased in parallel to the enhancement of total urine protein in 24 h in HSPN patients. There were statistically significant differences among these three groups of HSPN children (p < 0.05). Urinary MCP-1 correlated positively with urinary α₁-MG, mAlb, IgG, TRF and TUP in HSPN, whereas no correlation was observed with serum Cr and BUN.

CONCLUSIONS

MCP-1 was elevated in children with HSPN and correlated with proteinuria. Urinary MCP-1 could be used as a suitable, non-invasive biomarker to provide valuable information not only for the diagnosis of HSPN, but also for evaluation of severity of renal damage.

Urinary Biomarkers to Identify Autosomal Dominant Polycystic Kidney Disease Patients With a High Likelihood of Disease Progression

Introduction

The variable disease course of autosomal dominant polycystic kidney disease (ADPKD) makes it important to develop biomarkers that can predict disease progression, from a patient perspective and to select patients for renoprotective treatment. We therefore investigated whether easy-to-measure urinary biomarkers are associated with disease progression and have additional value over that of conventional risk markers.

Methods

At baseline, inflammatory, glomerular, and tubular damage markers were measured in 24-hour urine collections (albumin, IgG, kidney injury molecule−1 (KIM-1), N-acetyl-β-d-glucosaminidase (NAG), β2 microglobulin (β2MG), heart-type fatty acid binding protein (HFABP), macrophage migration inhibitory factor (MIF), neutrophil gelatinase-associated lipocalin (NGAL), and monocyte chemotactic protein−1 (MCP-1). Disease progression was expressed as annual change in estimated glomerular filtration rate (eGFR, Chronic Kidney Disease EPIdemiology equation), measured glomerular filtation rate (mGFR, using ¹²⁵I-iothalamate), or height-adjusted total kidney volume (htTKV). Multivariable linear regression was used to assess associations of these markers independent of conventional risk markers.

Results

A total of 104 ADPKD patients were included (40 ± 11 years, 39% female, eGFR 77 ± 30, mGFR 79 ± 30 ml/min per 1.73 m² and htTKV 852 [510−1244] ml/m). In particular, β2MG and MCP-1 were associated with annual change in eGFR, and remained associated after adjustment for conventional risk markers (standardized β = −0.35, P = 0.001, and standardized β = −0.29, P = 0.009, respectively). Adding β2MG and MCP-1 to a model containing conventional risk markers that explained annual change in eGFR significantly increased the performance of the model (final R² = 0.152 vs. 0.292, P = 0.001). Essentially similar results were obtained when only patients with an eGFR ≥ 60 ml/min per 1.73 m² were selected, or when change in mGFR was studied. Associations with change in htTKV were less strong.

Conclusion

Urinary β2MG and MCP-1 excretion were both associated with GFR decline in ADPKD, and had added value beyond that of conventional risk markers. These markers therefore have the potential to serve as predictive tools for clinical practice.

Serum myeloid-related protein 8/14 in minimal change- and glomerulonephritis-related nephrotic syndrome

BACKGROUND

Myeloid-related protein 8/14 (MRP8/14) forms stable heterodimers and is the major calcium-binding protein secreted by activated granulocytes and monocytes. We evaluated whether serum MRP8/14 level is a useful indicator for a differential diagnosis of glomerulonephritis (GN)- and minimal change disease (MC)- related nephrotic syndrome (NS).

METHODS

Serum MRP8/14 complex was evaluated in 37 NS patients with MC or GN. These patients were divided into two groups. Group 1 consisted of 13 NS patients with MC, and group 2 consisted of 24 NS patients with GN. Group 2 was further divided into four subgroups: IgA nephropathy (IgAN; n = 5), Henoch-Schönlein purpura nephritis (HSPN; n = 6), focal segmental glomerulosclerosis (FSGS; n = 12), and acute GN Poststreptococcal acute glomeruloNephritis (PSAGN; n = 1).

RESULTS

The clinical manifestations, laboratory findings, serum MRP8/14 level, and renal accumulation of MRP8 were investigated for each group. No significant inter-group differences were observed for serum total protein, serum albumin, or blood urea nitrogen and urinary protein excretions. Mean serum MRP8/14 in the IgAN, HSPN, FSGS, and PSAGN groups was higher than in group 1. Further, the mean glomerular and interstitial MRP8 staining scores in the IgAN, HSPN, and PSAGN groups were higher than in group 1.

CONCLUSIONS

Serum MRP8/14 level may be a useful indicator for differential diagnosis between GN- and MC- related NS.

The role of Krüppel-like factor 4 in transforming growth factor-β-induced inflammatory and fibrotic responses in human proximal tubule cells

Krüppel-like factor 4 (KLF4) is known to mitigate inflammation in several cell types. Using human proximal tubule cells, the present study aimed to investigate the role of KLF4 in regulating transforming growth factor (TGF)-β₁ induced inflammatory and fibrotic responses. Human kidney proximal tubular cells were exposed to high glucose, or TGF-β₁ and KLF4 expressions were determined. Cells were then transfected with empty vector or KLF4 and exposed to 2-ng/mL TGF-β₁ for up to 72 h. Inflammatory proteins (macrophage migration inhibitory factor and monocyte chemoattractant protein-1) and pro-fibrotic proteins (fibronectin and collagen IV) were measured after 72 h by enzyme-linked immunosorbent assay and western blot, respectively. To determine the relevance to in vivo models of chronic kidney disease, KLF4 protein expression in streptozotocin-induced diabetic mice was determined. Krüppel-like factor 4 messenger RNA (mRNA) levels were significantly reduced in high glucose-treated human kidney proximal tubular cells. High glucose increased TGF-β₁ mRNA expression, which significantly increased migration inhibitory factor and monocyte chemoattractant protein-1 protein secretion. Transforming growth factor-β₁ significantly increased fibronectin and collagen IV protein expression. The overexpression of KLF4 significantly reduced TGF-β-mediated increases in migration inhibitory factor and monocyte chemoattractant protein-1 but had no effect on TGF-β-mediated fibronectin and collagen IV mRNA and protein expression. The levels of KLF4 mRNA were significantly reduced in the diabetic kidney, and diabetic animals had a significant reduction in renal tubular expression of KLF4 proteins. This data suggest that KLF4 reduces inflammation induced by TGF-β₁, suggesting a therapeutic role for KLF4 in diabetic nephropathy.

Macrophage migration inhibitory factor urinary excretion revisited – MIF a potent predictor of the immunosuppressive treatment outcomes in patients with proliferative primary glomerulonephritis

Background

Macrophage migration inhibitory factor (MIF) is a cytokine that shares many activities with other pro-inflammatory cytokines in primary glomerulonephritis (GN). This study assesses the influence of immunosuppressive treatment on serum and urine MIF in patients with proliferative (PGN) and non-proliferative (NPGN) glomerulonephritis, and evaluates the potential of MIF in predicting outcomes.

Methods

Eighty-four patients (45 males and 39 females) with primary GN were included. Urinary excretion of MIF (ng/mg of urinary creatinine) was measured both pre- and post-treatment with combined steroids and cyclophosphamide. After a 12-month follow-up, the patients were retrospectively divided into four subgroups: responders of proliferative GN (R-PGN), non-responders of proliferative GN (NR-PGN), responders of non-proliferative GN (R-NPGN) and non-responders of non-proliferative GN (NR-NPGN).

Results

The median pre-treatment urinary MIF values were higher in PGN than in NPGN (3.6 versus 2.2; ANOVA P = 0.039). The highest pre-treatment urinary excretion of MIF was observed in NR-PGN (median 6.1), which was significantly higher than other subgroups (ANOVA P < 0.05). The treatment significantly reduced MIF urinary excretion only in R-PGN (P < 0.01). In NR-PGN, pre- (5.9 ± 2.9 pg/mgCr) and post-treatment mean MIF excretion (4.9 ± 2.3 pg/mgCr) exceeded the calculated cut off value (3.3 pg/mgCr).

Conclusion

MIF urinary excretion appears to be a prognostic marker of therapy outcomes only in proliferative glomerulonephritis, in which lower urinary MIF may be linked with good prognosis, whereas a higher MIF urinary excretion value was a marker of unfavorable therapy outcomes. In Non-Responders, urinary MIF measurements may help to reconsider the choice of the immunosuppressive regimen at early stages of the treatment and act as an impulse to search for new therapeutic strategies.

MIF, CD74 and other partners in kidney disease: tales of a promiscuous couple

Macrophage migration inhibitory factor (MIF) is increased in kidney and urine during kidney disease. MIF binds to and activates CD74 and chemokine receptors CXCR2 and CXCR4. CD74 is a protein trafficking regulator and a cell membrane receptor for MIF, D-dopachrome tautomerase (D-DT/MIF-2) and bacterial proteins. MIF signaling through CD74 requires CD44. CD74, CD44 and CXCR4 are upregulated in renal cells in diseased kidneys and MIF activation of CD74 in kidney cells promotes an inflammatory response. MIF or CXCR2 targeting protects from experimental kidney injury, CD44 deficiency modulates kidney injury and CXCR4 activation promotes glomerular injury. However, the contribution of MIF or MIF-2 to these actions of MIF receptors has not been explored. The safety and efficacy of strategies targeting MIF, CD74, CD44 and CXCR4 are under study in humans.

Macrophage migration inhibitory factor: a multifunctional cytokine in rheumatic diseases

Macrophage migration inhibitory factor (MIF) was originally identified in the culture medium of activated T lymphocytes as a soluble factor that inhibited the random migration of macrophages. MIF is now recognized to be a multipotent cytokine involved in the regulation of immune and inflammatory responses. Moreover, the pivotal nature of its involvement highlights the importance of MIF to the pathogenesis of various inflammatory disorders and suggests that blocking MIF may be a useful therapeutic strategy for treating these diseases. This paper discusses the function and expressional regulation of MIF in several rheumatic diseases and related conditions.

The role of macrophage migration inhibitory factor in ocular surface disease pathogenesis after chemical burn in the murine eye

PURPOSE

To evaluate the role of macrophage migration inhibitory factor (MIF) in the wound healing process following severe chemical burns to the ocular surface.

METHODS

Chemical burning of the ocular surface was induced in mice (C57BL/6) via the application of 0.1 M NaOH. Macrophage migration inhibitory factor (MIF), tumor necrosis factor-α (TNF-α), and interleukin-1β (IL-1β) mRNA expression in the ocular surface and lacrimal gland was evaluated via real-time reverse transcription PCR on days 2, 7, and 30 after induction of the chemical burn. The expression of MIF protein in the ocular surface and lacrimal gland was evaluated via western blot analysis. Immunohistochemical staining was conducted to detect MIF and vasculoendothelial growth factor in the cornea during the wound healing process. The angiogenic role of MIF was further evaluated using an 8-0 polyglactin suture technique to induce corneal neovascularization.

RESULTS

MIF, TNF-α, and IL-1β mRNA expression were elevated significantly in the ocular surface up to day 30 after chemical burn induction. TNF-α alone was elevated in the lacrimal gland. MIF protein elevation was confirmed via western blot analysis, and the spatial similarity of MIF and VEGF expression in the cornea was noted during the wound healing process. 8-0 polyglactin sutures soaked in MIF induced significantly higher numbers of new vessels on the mouse cornea after 7 days (p=0.003, Mann-Whitney test).

CONCLUSIONS

These findings indicate that MIF performs a crucial role in wound healing on the ocular surface after the induction of chemical burns.

Association of urinary biomarkers with disease severity in patients with autosomal dominant polycystic kidney disease: a cross-sectional analysis

BACKGROUND

Disease monitoring of autosomal dominant polycystic kidney disease (ADPKD) will become more important with potential upcoming therapeutic interventions. Because serum creatinine level is considered of limited use and measurement of effective renal blood flow (ERBF) and total renal volume are time consuming and expensive, there is a need for other biomarkers. We aimed to investigate which urinary markers have increased levels in patients with ADPKD; whether these urinary markers are associated with measured glomerular filtration rate (mGFR), ERBF, and total renal volume; and whether these associations are independent of albuminuria (urine albumin excretion [UAE]).

STUDY DESIGN

Diagnostic test study.

SETTING & PARTICIPANTS

102 patients with ADPKD (Ravine criteria) and 102 age- and sex-matched healthy controls.

INDEX TEST

24-hour urinary excretion of glomerular (immunoglobulin G), proximal tubular (kidney injury molecule 1 [KIM-1], N-acetyl-β-d-glucosaminidase, neutrophil gelatinase-associated lipocalin [NGAL], and β(2)-microglobulin), and distal tubular (heart-type fatty acid binding protein [H-FABP]) damage markers and inflammatory markers (monocyte chemotactic protein 1 [MCP-1] and macrophage migration inhibitory factor).

REFERENCE TEST

Disease severity assessed using measures of kidney function (mGFR and ERBF, measured using clearance of iothalamate labeled with iodine 125 and hippuran labeled with iodine 131 during continuous infusion, respectively) and structure (total renal volume, measured using magnetic resonance imaging).

OTHER MEASUREMENTS

24-hour UAE.

RESULTS

In 102 patients with ADPKD (aged 40 ± 11 years; 58% men), levels of all measured urinary biomarkers were increased compared with healthy controls. Excretion of immunoglobulin G and albumin relatively were most increased. ERBF and mGFR values were associated with urinary excretion of β(2)-microglobulin, NGAL, and H-FABP independent of UAE, whereas total renal volume was associated with KIM-1, NGAL, and MCP-1 independent of UAE.

LIMITATIONS

Cross-sectional, single center.

CONCLUSIONS

Levels of markers for multiple parts of the nephron are increased in patients with ADPKD. In addition to measurement of UAE, measurement of urinary β(2)-microglobulin, KIM-1, H-FABP, MCP-1, and especially NGAL could be of value for determination of disease severity in patients with ADPKD.

Effects of different LDL particles on inflammatory molecules in human mesangial cells

AIMS/HYPOTHESIS

Inflammation is a mechanism of glomerular damage in chronic glomerulopathies. LDL may increase the production of inflammatory cytokines in renal tissues. However, the relative role of native, oxidised and glycated LDL in promoting this process has been only partially elucidated.

METHODS

We tested the inflammatory and proapoptotic effects of native, oxidised and glycated LDL in human mesangial cells (HMCs) by measuring levels of IL6, CD40 and macrophage migration inhibitory factor (MIF) genes, MIF protein, release of IL6, soluble CD40, fibronectin and laminin, early and late apoptosis, and extracellular regulated kinases (ERK) 1/2 and c-Jun N-terminal kinase (JNK) activation.

RESULTS

IL6 and CD40 mRNA were dose-dependently upregulated by all three species; this was closely paralleled by their increased release. MIF mRNA was potently stimulated by modified LDL, as confirmed by immunostaining. Fibronectin and laminin release was stimulated by both oxidised and glycated, but not native, LDL. All LDL species induced some increase in late, but not early, apoptosis, and similarly activated JNK2/3 phosphorylation; in contrast, ERK1/2 phosphorylation was more strongly upregulated by oxidised than either native or glycated LDL.

CONCLUSIONS

In HMCs, the production and release of IL6 and CD40 is stimulated by both native and modified LDL, while MIF is more strongly stimulated by oxidised LDL. Regarding the pattern of mesangial expansion, fibronectin and laminin are upregulated by oxidised and glycated LDL. Apoptosis, if modest, is induced by all species. Intracellular signalling of native and modified LDL involves JNK2/3 and, perhaps more specifically, ERK1/2. Tight control of the lipid profile may be useful in preserving kidney function in patients with metabolic alterations.

Association of the macrophage migration inhibitory factor -173*C allele with childhood nephrotic syndrome

Macrophage migration inflammatory factor (MIF) is a proinflammatory cytokine with a unique role as the physiologic counterregulator of the immunosuppressive effects of glucocorticoids. MIF has been implicated in the pathogenesis of glomerular inflammation. The MIF promoter contains a G/C polymorphism that is functionally relevant, with the C allele being associated with higher MIF production and linked to susceptibility to inflammatory diseases. We genotyped the MIF -173 polymorphism in 257 children with idiopathic nephrotic syndrome (INS) and 355 controls. Frequency of carriers of the high-producer MIF -173*C allele was higher in patients with INS (31.7%) than in controls (22.0%) [odds ratio (OR) 1.67, p = 0.006] The MIF -173 C allele was more frequent in steroid-resistant patients (43.5%) compared with steroid responders (22.8%) (OR 2.61, p = 0.0005). This difference was particularly evident in focal segmental glomerulosclerosis patients (OR 14.0, p = 0.002). No association with response to cyclosporin A was found. Carriers of the MIF -173*C allele had a significantly higher probability of end-stage renal disease (ESRD) compared with G/G homozygous patients within 5 years from onset (log rank 5.11 p = 0.024). These results underscore the role of MIF in INS disease progression and in the response to glucocorticoid treatment and suggest that screening of MIF genotype at disease onset may identify patients requiring a more aggressive therapeutic approach.

Serum macrophage migration inhibitory factor (MIF) levels after allogeneic hematopoietic stem cell transplantation

Macrophage migration inhibitory factor (MIF) may play an important role in the pathogenesis of acute graft-versus-host disease (aGVHD) after allogeneic hematopoietic stem cell transplantation (allo-HSCT), as MIF plays an important role to regulate the production of tumor necrosis factor-alpha (TNF-alpha), one of the inflammatory cytokines which induces and exacerbates aGVHD. We examined the association between serum MIF levels and aGVHD vs. chronic GVHD (cGVHD) in allo-SCT patients in this study. We found a significant increase in the peak serum MIF (14.46 ng +/- 1.47 ng/ml) at onset in patients that developed aGVHD (n = 23, P = 0.009). We also found that mean serum MIF levels in patients who developed extensive type cGVHD within 6 months (12.58 +/- 2.18 ng/ml, n = 13) were significantly higher than MIF levels before allo-HSCT (7.86 +/- 1.17 ng/ml, n = 19, P = 0.04). Therefore, we speculated that serum MIF levels increase during the active phase of both aGVHD and cGVHD.

Effect of macrophage migration inhibitory factor (MIF) on acute graft-versus-host disease in a murine model of allogeneic stem cell transplantation

Macrophage migration inhibitory factor (MIF) may play an important role in the pathogenesis of acute graft-versus-host disease (aGVHD) after allogeneic hematopoietic stem cell transplantation (HSCT). We examined whether MIF has an influence on the development of aGVHD and survival using BALB/c-based MIF knock-out (MIF KO) mice. Although MIF expression was observed in lymphocytes that had infiltrated the liver during aGVHD in both wild-type (WT) and MIF KO mice that received bone marrow cells (BM) and spleen cells (SP) from C57BL/6N mice, no significant difference was found in severity of aGVHD or survival rate between the two groups of mice. However, MIF level had decreased at 1 week after HSCT when MIF KO mice were used as the recipients. In the experiment using MIF KO mice as the donors, the recipient mice transplanted with BM and SP from MIF KO mice had significantly lower aGVHD scores on days 14, 21, and 35 than those in the recipient mice transplanted with BM and SP from WT-BALB/c mice. Histopathological findings supported these observations, showing that the bile ducts and lobules in the liver were destroyed by infiltrating MIF-expressing lymphocytes in the recipients of BM and SP from WT-BALB/c mice, while the bile ducts were not destroyed even by infiltrating MIF-deficient lymphocytes in the recipients of BM and SP from MIF KO mice. Therefore, these findings suggest that MIF has an effect on the development of aGVHD in a murine model of allogeneic stem cell transplantation.

Macrophage Migration Inhibitory Factor is Increased in the Urine of Patients With Urinary Tract Infection: Macrophage Migration Inhibitory Factor-Protein Complexes in Human Urine

PURPOSE

MIF is a proinflammatory cytokine present in preformed stores in human urothelium. In animal models of bladder inflammation, including bacterial cystitis, MIF is up-regulated in the bladder and released from the bladder as a high molecular weight complex. We compared urine MIF amounts in patients with UTI to that in patients without UTI, and we examined and identified MIF-protein complexes in urine.

MATERIALS AND METHODS

Using enzyme-linked immunosorbent assay we compared MIF levels in the urine of 14 patients with UTI to levels in 16 controls with no UTI. Western blotting under native, denaturing and reducing conditions was done to examine MIF complexes found in urine. Mass spectrometry identified MIF associated proteins in urine, while co-immunoprecipitation confirmed the associations.

RESULTS

Mean urine MIF amounts +/- SEM determined by enzyme-linked immunosorbent assay were significantly greater in 14 patients with UTI compared to that in 16 controls (1.96 +/- 0.40 vs 0.59 +/- 0.09 ng/mg creatinine, p <0.01). Western blotting under denaturing conditions showed several high molecular weight complexes (100 to 165 kDa) that increased in UTI urine as well as typical, monomeric MIF (12 kDa). Mass spectrometry identified associated MIF proteins, including ceruloplasmin, albumin and uromodulin. Co-immunoprecipitation confirmed mass spectrometry findings and also identified MIF interaction with alpha-2-macroglobulin.

CONCLUSIONS

Increased urine MIF amounts in patients with bacterial cystitis support our experimental evidence showing a role for MIF in pelvic visceral inflammation. The novel finding of an association of MIF with other urine proteins suggest that the physiologically relevant form of MIF may be an MIF-protein complex.