[Exploring the mechanism of IgA vasculitis pathogenesis through the interaction of thrombin and inflammatory factors using urinary proteomics]. / è¿ç”¨å°¿è›‹ç™½ç»„å­¦æŠ€æœ¯æŽ¢ç´¢å‡è¡€é ¶ä¸Žç‚Žç—‡å› å­ç›¸äº’ä½œç”¨å‚ä¸ŽIgAè¡€ç®¡ç‚Žå‘ç— çš„æœºåˆ¶.

OBJECTIVES: To explore the evidence, urinary biomarkers, and partial mechanisms of hypercoagulability in the pathogenesis of IgA vasculitis (IgAV). METHODS: Differential expression of proteins in the urine of 10 healthy children and 10 children with IgAV was screened using high-performance liquid chromatography-tandem mass spectrometry, followed by Reactome pathway analysis. Protein-protein interaction (PPI) network analysis was conducted using STRING and Cytoscape software. In the validation cohort, 15 healthy children and 25 children with IgAV were included, and the expression levels of differential urinary proteins were verified using enzyme-linked immunosorbent assay. RESULTS: A total of 772 differential proteins were identified between the IgAV group and the control group, with 768 upregulated and 4 downregulated. Reactome pathway enrichment results showed that neutrophil degranulation, platelet activation, and hemostasis pathways were involved in the pathogenesis of IgAV. Among the differential proteins, macrophage migration inhibitory factor (MIF) played a significant role in neutrophil degranulation and hemostasis, while thrombin was a key protein in platelet activation and hemostasis pathways. PPI analysis indicated that thrombin directly interacted with several proteins involved in inflammatory responses, and these interactions involved MIF. Validation results showed that compared to healthy children, children with IgAV had significantly higher urine thrombin/creatinine and urine MIF/creatinine levels (P<0.05). CONCLUSIONS: Thrombin contributes to the pathogenesis of IgAV through interactions with inflammatory factors. Urinary thrombin and MIF can serve as biomarkers reflecting the hypercoagulable and inflammatory states in children with IgAV.

Distinct patterns of serum and urine macrophage migration inhibitory factor kinetics predict death in sepsis: a prospective, observational clinical study.

Macrophage migration inhibitory factor (MIF) has been considered as a biomarker in sepsis, however the predictive value of the pattern of its kinetics in the serum and in the urine has remained unclarified. It is also unclear whether the kinetics of MIF are different between males and females. We conducted a single-center prospective, observational study with repeated measurements of MIF in serum and urine on days 0, 2, and 4 from admission to the intensive care unit (ICU) in 50 adult septic patients. We found that in patients who died within 90 days, there was an increase in serum MIF level from day 0 to 4, whereas in the survivors there was rather a decrease (p = 0.018). The kinetics were sex-dependent as the same difference in the pattern was present in males (p = 0.014), but not in females (p = 0.418). We also found that urine MIF was markedly lower in patients who died than in survivors of sepsis (p < 0.050). Urine MIF levels did not show temporal changes: there was no meaningful difference between day 0 and 4. These results suggest that kinetics of serum MIF during the initial days from ICU admission can predict death, especially in male patients. Additionally, lower urine MIF levels can also indicate death without showing meaningful temporal kinetics.

Macrophage migration inhibitory factor promotes renal injury induced by ischemic reperfusion.

Macrophage migration inhibitory factor (MIF) is pleiotropic cytokine that has multiple effects in many inflammatory and immune diseases. This study reveals a potential role of MIF in acute kidney injury (AKI) in patients and in kidney ischemic reperfusion injury (IRI) mouse model in MIF wild-type (WT) and MIF knockout (KO) mice. Clinically, plasma and urinary MIF levels were largely elevated at the onset of AKI, declined to normal levels when AKI was resolved and correlated tightly with serum creatinine independent of disease causes. Experimentally, MIF levels in plasma and urine were rapidly elevated after IRI-AKI and associated with the elevation of serum creatinine and the severity of tubular necrosis, which were suppressed in MIF KO mice. It was possible that MIF may mediate AKI via CD74/TLR4-NF-κB signalling as mice lacking MIF were protected from AKI by largely suppressing CD74/TLR-4-NF-κB associated renal inflammation, including the expression of MCP-1, TNF-α, IL-1ß, IL-6, iNOS, CXCL15(IL-8 in human) and infiltration of macrophages, neutrophil, and T cells. In conclusion, our study suggests that MIF may be pathogenic in AKI and levels of plasma and urinary MIF may correlate with the progression and regression of AKI.

MIF/CD74 axis is a target for metformin therapy in diabetic podocytopathy - real world evidence.

Introduction：To observe the effects of metformin on urinary excretion of MIF, CD74 and podocalyxin in type 2 diabetics and to explore its possible renoprotective mechanisms. METHODS: 202 uncontrolled type 2 diabetics, who were previously prescribed sulfonylurea monotherapy(n=100) or sulfonylurea in combination with metformin (n=102) were enrolled in the study. The amount of macrophage migration inhibitory factor(MIF) and CD74 in serum, urinary MIF to creatine ratio(UMCR), urinary CD74 to creatine ratio(UCCR), urinary albumin to creatine ratio(UACR) and urinary podocalyxin to creatine ratio (UPCR) were determined. RESULTS: Metabolic parameters including fasting blood glucose, postprandial 2 hours blood glucose, hemoglobin A1c, MIF and CD74 in serum were comparable between the two groups. Moreover, metformin add-on therapy showed significantly better efficacy in reducing UMCR, UCCR, UPCR and UACR in comparison with those in sulfonylurea monotherapy group, respectively. UPCR had positive correlation with UACR, UMCR and UCCR (r＝0.73, r=0.69, r=0.62, P < 0.01), respectively. CONCLUSIONS: Metformin could present its podocyte-protective capacity in type 2 diabetics and the underlying mechanisms may be partly attributed to its effects in suppressing MIF-CD74 axis mediated inflammatory cascade response. < p > < /p >.

The protective role of macrophage migration inhibitory factor in acute kidney injury after cardiac surgery.

Acute kidney injury (AKI) represents the most frequent complication after cardiac surgery. Macrophage migration inhibitory factor (MIF) is a stress-regulating cytokine that was shown to protect the heart from myocardial ischemia-reperfusion injury, but its role in the pathogenesis of AKI remains unknown. In an observational study, serum and urinary MIF was quantified in 60 patients scheduled for elective conventional cardiac surgery with the use of cardiopulmonary bypass. Cardiac surgery triggered an increase in MIF serum concentrations, and patients with high circulating MIF (>median) 12 hours after surgery had a significantly reduced risk of developing AKI (relative risk reduction, 72.7%; 95% confidence interval, 12 to 91.5%; P = 0.03). Experimental AKI was induced in wild-type and Mif-/- mice by 30 min of ischemia followed by 6 or 24 hours of reperfusion, or by rhabdomyolysis. Mif-deficient mice exhibited increased tubular cell injury, increased regulated cell death (necroptosis and ferroptosis), and enhanced oxidative stress. Therapeutic administration of recombinant MIF after ischemia-reperfusion in mice ameliorated AKI. In vitro treatment of tubular epithelial cells with recombinant MIF reduced cell death and oxidative stress as measured by glutathione and thiobarbituric acid reactive substances in the setting of hypoxia. Our data provide evidence of a renoprotective role of MIF in experimental ischemia-reperfusion injury by protecting renal tubular epithelial cells, consistent with our observation that high MIF in cardiac surgery patients is associated with a reduced incidence of AKI.

Elevated Urine Levels of Macrophage Migration Inhibitory Factor in Inflammatory Bladder Conditions: A Potential Biomarker for a Subgroup of Interstitial Cystitis/Bladder Pain Syndrome Patients.

OBJECTIVE: To investigate whether urinary levels of macrophage migration inhibitory factor (MIF) are elevated in interstitial cystitis/bladder pain syndrome (IC/BPS) patients with Hunner lesions and also whether urine MIF is elevated in other forms of inflammatory cystitis. METHODS: Urine samples were assayed for MIF by enzyme-linked immunosorbent assay. Urine samples from 3 female groups were examined: IC/BPS patients without (N = 55) and with Hunner lesions (N = 43), and non-IC/BPS patients (N = 100; control group; no history of IC/BPS; cancer or recent bacterial cystitis). Urine samples from 3 male groups were examined: patients with bacterial cystitis (N = 50), radiation cystitis (N = 18) and noncystitis patients (N = 119; control group; negative for bacterial cystitis). RESULTS: Urine MIF (mean MIF pg/mL ± standard error of the mean) was increased in female IC/BPS patients with Hunner lesions (2159 ± 435.3) compared with IC/BPS patients without Hunner lesions (460 ± 114.5) or non-IC/BPS patients (414 ± 47.6). Receiver operating curve analyses showed that urine MIF levels discriminated between the 2 IC groups (area under the curve = 72%; confidence interval 61%-82%). Male patients with bacterial and radiation cystitis had elevated urine MIF levels (2839 ± 757.1 and 4404 ± 1548.1, respectively) compared with noncystitis patients (681 ± 75.2). CONCLUSION: Urine MIF is elevated in IC/BPS patients with Hunner lesions and also in patients with other bladder inflammatory and painful conditions. MIF may also serve as a noninvasive biomarker to select IC/BPS patients more accurately for endoscopic evaluation and possible anti-inflammatory treatment.

Macrophage Migration Inhibitory Factor Predicts Outcome in Complex Aortic Surgery.

The perioperative inflammatory response is associated with outcome after complex aortic repair. Macrophage migration inhibitory factor (MIF) shows protective effects in ischemia-reperfusion (IR), but also adverse pro-inflammatory effects in acute inflammation, potentially leading to adverse outcome, which should be investigated in this trial. This prospective study enrolled 52 patients, of whom 29 (55.7%) underwent open repair (OR) and 23 (44.3%) underwent endovascular repair (ER) between 2014 and 2015. MIF serum levels were measured until 72 h post-operatively. We used linear mixed models and ROC analysis to analyze the MIF time-course and its diagnostic ability. Compared to ER, OR induced higher MIF release perioperatively; at 12 h after ICU admission, MIF levels were similar between groups. MIF course was significantly influenced by baseline MIF level (P = 0.0016) and acute physiology and chronic health evaluation (APACHE) II score (P = 0.0005). MIF level at 24 h after ICU admission showed good diagnostic value regarding patient survival [sensitivity, 80.0% (28.4-99.5%); specificity, 51.2% (35.1-67.1%); AUC, 0.688 (0.534-0.816)] and discharge modality [sensitivity, 87.5% (47.3-99.7%); specificity, 73.7% (56.9-86.6%), AUC, 0.789 (0.644-0.896)]. Increased perioperative MIF-levels are related to an increased risk of adverse outcome in complex aortic surgery and may represent a biomarker for risk stratification in complex aortic surgery.

Comparison of macrophage migration inhibitory factor and neutrophil gelatinase-associated lipocalin-2 to predict acute kidney injury after liver transplantation: An observational pilot study.

INTRODUCTION: Several biomarkers have been suggested as early predictors of acute kidney injury (AKI) after orthotopic liver transplantation (OLT). Neutrophil gelatinase-associated lipocalin-2 (NGAL) appears to be a promising predictor of AKI after OLT, but the clinical benefit remains to be proven. Recently, systemic macrophage migration inhibitory factor (MIF) has been proposed as early indicator for requirement of renal replacement therapy after OLT. The aim of this prospective, observational pilot study was to compare the predictive values of serum and urinary MIF for severe AKI after OLT to those of serum and urinary NGAL. METHODS: Concentrations of MIF and NGAL were measured in serum and urine samples collected from patients undergoing OLT. Acute kidney injury was classified according to the KDIGO criteria, with stages 2 and 3 summarized as severe AKI. Areas under the receiver operating curves (AUC) were calculated to assess predictive values of MIF and NGAL for the development of severe AKI. RESULTS: Forty-five patients (mean age 55±8 years) were included. Nineteen patients (38%) developed severe AKI within 48 hours after reperfusion. At the end of OLT, serum MIF was predictive of severe AKI (AUC 0.73; 95% confidence intervals, CI 0.55-0.90; P = 0.03), whereas urinary MIF, serum NGAL, and urinary NGAL were not. On the first postoperative day, serum MIF (AUC 0.78; CI 0.62-0.93; P = 0.006), urinary MIF (AUC 0.71; CI 0.53-0.88; P = 0.03), and urinary NGAL (AUC 0.79; CI 0.64-0.93; P = 0.02) were predictive for severe AKI, while serum NGAL was not. CONCLUSION: In the setting of OLT, MIF and NGAL had similar predictive values for the development of severe AKI.

Urinary Macrophage Migration Inhibitory Factor as a Noninvasive Biomarker in Pediatric Henoch-Schönlein Purpura Nephritis.

PURPOSES: The aims of this study were to investigate urinary macrophage migration inhibitory factor (MIF) levels and their clinical significance in Henoch-Schönlein purpura (HSP) children with or without nephritis (N) and to assess the influence of steroid treatment on the urine MIF levels of HSPN patients. METHODS: Group I comprised 35 children with HSPN who were examined twice (A before treatment and B after steroid treatment). Group II comprised 41 children with HSP. The control group included 32 healthy children. Urinary MIF levels were measured via enzyme linked immunosorbent assay. The levels of serum creatinine, blood urea nitrogen, urinary microalbumin (mAlb), and 24-hour proteinuria were performed to determine their associations with MIF levels. RESULTS: Urinary MIF levels were significantly higher in group I compared with group II and the control group (P < 0.01); however, no significant difference was found between group II and the control group (P > 0.05). Upon examination, albeit urinary MIF concentration was significantly lower in group IB compared with group IA (P < 0.05), these concentrations were statistically higher than that of group II (P < 0.05). In addition, in the HSPN patients, the urinary MIF was positively associated with urinary microalbumin and 24-hour proteinuria but no association with serum creatinine and blood urea nitrogen. CONCLUSIONS: Elevated urinary MIF levels were found to be correlated with proteinuria in pediatric HSPN. An obvious decrease in urinary MIF concentrations among the children with HSPN was associated with steroid treatment. Urinary MIF can be used as a noninvasive biomarker in pediatric HSPN.

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.

Evaluation of biomarkers of cell cycle arrest and inflammation in prediction of dialysis or recovery after kidney transplantation.

Early prediction of delayed graft function (DGF) after kidney transplantation would facilitate patient management. Cell cycle arrest and inflammation are implicated in the pathogenesis of DGF. We assessed the utility of two novel acute kidney injury (AKI) biomarkers, urinary tissue inhibitor of metalloproteinases-2 (TIMP-2) and insulin-like growth factor-binding protein 7 (IGFBP7), and five inflammatory markers to predict DGF following deceased-donor kidney transplantation. Serial urine concentrations of TIMP-2 and IGFBP7 were measured immediately after transplantation in 56 recipients along with vascular endothelial growth factor-A (VEGF-A), macrophage migration inhibitory factor (MIF), monocyte chemotactic protein-1 (MCP-1), trefoil factor 3 (TFF3) and chemokine (C-X-C) ligand 16 (CXCL16). Delayed graft function (DGF) was defined as requirement for dialysis within 7 days. Integrated discrimination improvement analysis was used to evaluate whether these biomarkers enhanced prediction of DGF independently of a validated clinical risk prediction model. DGF occurred in 22 patients (39%). At 4 h after kidney reperfusion, the area under the receiver operator characteristic curve (AUC) for VEGF-A was good (AUC > 0.80); for TIMP-2, IGFBP7 and [TIMP-2] × [IGFBP7] fair (AUCs 0.70-0.79); and for MIF, MCP-1, TFF3 and CXCL16 poor (AUC < 0.70). Only TIMP-2 and VEGF significantly enhanced the DGF prediction at 4 and 12 h. The cell cycle arrest marker urinary TIMP-2 and the inflammatory biomarker VEGF-A are potentially useful adjuncts to clinical data for early prediction of DGF.

Uropathogenic Escherichia coli causes cortical tubular necrotic cell death and the release of macrophage migration inhibitory factor.

The macrophage migration inhibitory factor (MIF), a pro-inflammatory cytokine, is deregulated in acute kidney injury (AKI) through an unknown mechanism. In the present study, we used a previously described mouse model of ascending urinary tract infection in which uropathogenic Escherichia coli (UPEC) were transurethrally inoculated to induce kidney infections. Here, we show that urinary MIF was upregulated during AKI while MIF was abundantly expressed in the renal cortical tubules and that UPEC infection caused a decrease in tubular MIF. Infections with UPEC in vitro caused MIF release in a cell type-dependent manner, which was independent of receptor-mediated internalization, signal transduction, and transcription. Indeed, UPEC infection-induced necrotic cell death in vitro and in vivo correlated with extracellular acidification and processed MIF secretion. These data suggest that MIF is released by necrotic renal cortical tubular cells during UPEC infection.

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.

Urinary macrophage migration inhibitory factor serves as a potential biomarker for acute kidney injury in patients with acute pyelonephritis.

Conventional markers of kidney function that are familiar to clinicians, including the serum creatinine and blood urea nitrogen levels, are unable to reveal genuine injury to the kidney, and their use may delay treatment. Macrophage migration inhibitory factor (MIF) is a proinflammatory cytokine, and the predictive role and pathogenic mechanism of MIF deregulation during kidney infections involving acute kidney injury (AKI) are not currently known. In this study, we showed that elevated urinary MIF levels accompanied the development of AKI during kidney infection in patients with acute pyelonephritis (APN). In addition to the MIF level, the urinary levels of interleukin (IL)-1ß and kidney injury molecule (KIM)-1 were also upregulated and were positively correlated with the levels of urinary MIF. An elevated urinary MIF level, along with elevated IL-1ß and KIM-1 levels, is speculated to be a potential biomarker for the presence of AKI in APN patients.

Urinary macrophage migration inhibitory factor in children with urinary tract infection.

Macrophage migration inhibitory factor (MIF) plays an essential pathophysiological role in inflammatory reactions. The aim of this study was to investigate the clinical utility of urine MIF (uMIF) level in predicting urinary tract infections (UTI). This multicenter, prospective study was conducted over a 1-year period between March 2008 and March 2009. Sixty patients with symptomatic culture-proven UTI and 29 healthy children were recruited. Urine MIF was measured by enzyme-linked immunosorbent assay. The mean MIF level was found to be significantly higher in the UTI group than in the control group (1082.82 vs. 211.45 pg/ml, p = 0.0001). Receiver operating characteristic (ROC) analysis revealed that the optimal cut-off uMIF level was 295 pg/ml for uMIF to predict UTI. The sensitivity and specificity of this cut-off level were 91.7% and 69%, respectively. Mean uMIF/creatinine (Cr) was also significantly higher in the UTI group than in the control group (2400.69 vs. 267.56 pg/mgCr, p = 0.0001). At a cut-off of 815 pg/mgCr for uMIF/Cr, the sensitivity and specificity were 95 and 79%, respectively. The area under curve (AUC) was 0.848 (standard error 0.040, 95% confidence interval 0.756-0.915) for uMIF and 0.889 (0.034, 0.805-0.946) for uMIF/Cr. Urine MIF/Cr was significantly higher in the patients with a positive leukocyte esterase reaction in the urine (p = 0.047), leukocytosis (p = 0.0001) and positive C-reactive protein level in serum (p = 0.003). The uMIF level was not related to leukocytosis, positive CRP level in serum and leukocyte esterase reaction in the urine. Neither uMIF nor uMIF/Cr were correlated to the positive urine nitrite test, pyuria, urine pH and specific gravity (p > 0.05). These results suggest that urine MIF and uMIF/Cr can be used for the early prediction of UTI in children.

Urine macrophage migration inhibitory factor (MIF) in children with urinary tract infection: a possible predictor of acute pyelonephritis.

Macrophage migration inhibitory factor (MIF) is an important pro-inflammatory cytokine expressed at sites of inflammation. We have assessed this factor (MIF) in urinary tract infections with the aim of determining a non-invasive and sensitive method to differentiate upper and lower renal involvement. Thirty-three pediatric patients with urinary track infection (25 with acute pyelonephritis, eight with acute cystitis) and 40 healthy subjects were recruited for this prospective case-control study. Pyelonephritis was differentiated from cystitis by dimercaptosuccinic acid (DMSA) scan. Urinary MIF concentration was determined using an enzyme-linked immunosorbent assay method. The urine MIF/creatinine (Cr) ratio was significantly higher in pyelonephritis patients than in those with acute cystitis and the control group (P < 0.001). The optimal cut-point of 4.90 pg/micromol Cr for the urine MIF/Cr ratio has the potential to be a biomarker for distinguishing patients with acute pyelonephritis from those with acute cystitis. Determination of the urinary MIF was also useful in selecting the patients at risk of permanent renal damage. Of those patients with pyelonephritis, based on the DMSA scan at the time of infection, scarring on follow-up DMSA scan 9-12 months later occurred in patients with the highest urinary MIF/Cr ratios. We conclude that the urine MIF/Cr ratio is a sensitive test for differentiating acute pyelonephritis from acute cystitis and also for detecting children with acute pyelonephritis who are at a higher risk for permanent renal scars in the future.

Cyclophosphamide-induced cystitis increases bladder CXCR4 expression and CXCR4-macrophage migration inhibitory factor association.

BACKGROUND: Macrophage migration inhibitory factor (MIF) is a pro-inflammatory cytokine involved in cystitis and a non-cognate ligand of the chemokine receptor CXCR4 in vitro. We studied whether CXCR4-MIF associations occur in rat bladder and the effect of experimental cystitis. METHODS AND FINDINGS: Twenty male rats received saline or cyclophosphamide (40 mg/kg; i.p.; every 3(rd) day) to induce persistent cystitis. After eight days, urine was collected and bladders excised under anesthesia. Bladder CXCR4 and CXCR4-MIF co-localization were examined with immunhistochemistry. ELISA determined MIF and stromal derived factor-1 (SDF-1; cognate ligand for CXCR4) levels. Bladder CXCR4 expression (real-time RTC-PCR) and protein levels (Western blotting) were examined. Co-immunoprecipitations studied MIF-CXCR4 associations.Urothelial basal and intermediate (but not superficial) cells in saline-treated rats contained CXCR4, co-localized with MIF. Cyclophosphamide treatment caused: 1) significant redistribution of CXCR4 immunostaining to all urothelial layers (especially apical surface of superficial cells) and increased bladder CXCR4 expression; 2) increased urine MIF with decreased bladder MIF; 3) increased bladder SDF-1; 4) increased CXCR4-MIF associations. CONCLUSIONS: These data demonstrate CXCR4-MIF associations occur in vivo in rat bladder and increase in experimental cystitis. Thus, CXCR4 represents an alternative pathway for MIF-mediated signal transduction during bladder inflammation. In the bladder, MIF may compete with SDF-1 (cognate ligand) to activate signal transduction mediated by CXCR4.

Differential chemokine expression in tubular cells in response to urinary proteins from patients with nephrotic syndrome.

BACKGROUND AND AIM: Comparison of urine proteins in idiopathic minimal change disease (MCD) and focal segmental glomerulosclerosis (FSGS) patients has been previously conducted, but the relationship between the severity of tubular injury and the composition of urine proteins in various kidney diseases is unknown. This study aimed to investigate the chemokine expression in human tubular cells in response to urine proteins from patients with nephrotic syndrome. METHODS: Urine proteins collected from patients with MCD or FSGS were extracted by ultrafiltration and coincubated with HK-2 cells. The expression of the RANTES and MIF genes and the activation of p38 and extracellular regulated kinase were determined. RESULTS: The urine proteins from both MCD and FSGS patients contained a primary band of proteins with Mr of approximately 62 kDa. The major cytokines present in urine proteins from MCD and FSGS patients were IL-6 and IL-8, while IL-1beta, IL-10, IL-12p70 and TNF-alpha were only detectable. We observed time- and dose-dependent increases in RANTES and MIF expression with urine protein treatment in HK-2 cells. The urine proteins from FSGS patients induced a higher expression of these two chemokines in HK-2 cells compared to the urine proteins from MCD patients. ERK and p38 were activated by urine proteins from either MCD or FSGS patients. Pretreatment with SB203580 or PD98059 abolished the increase in RANTES and MIF expression induced by urine proteins from FSGS patients, while only SB203580 suppressed the high expression induced by urine proteins from MCD patients. CONCLUSION: These findings indicate that the urine proteins from MCD and FSGS patients induce a differential expression of RANTES and MIF in tubular cells through distinct activation of MAPK-related signaling pathways.

Urine macrophage migration inhibitory factor in pediatric systemic lupus erythematosus.

We reported a series of ten patients with lupus nephritis (five patients in the relapse phase and five in the remission phase) and measured the macrophage migration inhibitory factor (MIF), an important pro-inflammatory cytokine with probable role in the pathogenesis of many inflammatory diseases, in their urine samples. MIF/creatinine (Cr) ratio directly correlated with disease activity and it does not have any significant difference between inactive disease and normal ones. We found that the urine MIF/Cr ratio not only differentiates active disease from inactive disease and normal ones but also correlates with the activity indices of renal pathology.