The role of cytokine in the lupus nephritis

Coordinated Priming of NKG2D Pathway by IL-15 Enhanced Functional Properties of Cytotoxic CD4+CD28- T Cells Expanded in Systemic Lupus Erythematosus

Systemic lupus erythematosus (SLE) is a systemic autoimmune disorder, and numerous aberrations of T cell responses have been reported and were implicated in its pathophysiology. Recently, CD4-positive T cells with cytotoxic potential were shown to be involved in autoimmune disease progression and tissue damage. However, the effector functions of this cell type and their potential molecular mechanisms in SLE patients remain to be elucidated. In this study, we find that cytotoxic CD4+CD28- T cells are expanded in SLE patients with flow cytometry analysis, and the percentage of CD4+CD28- T cells positively correlates with the Systemic Lupus International Collaborating Clinics/ACR Damage Index (SDI). Furthermore, our study suggests that interleukin-15 (IL-15) promotes the expansion, proliferation, and cytotoxic function of CD4+CD28- T cells in SLE patients through activation of the Janus kinase3-STAT5 pathway. Further study indicates that IL-15 not only mediates the upregulation of NKG2D, but also cooperates with the NKG2D pathway to regulate the activation of the phosphatidylinositol 3-kinase (PI3K)/protein kinase B (AKT) pathway. Together, our study demonstrated that proinflammatory and cytolytic CD4+CD28- T cells expand in SLE patients. The pathogenic potential of these CD4+CD28- T cells is driven by the coupling of the IL-15/IL-15R signaling pathway and the NKG2D/DAP10 signaling pathway, which may open new avenues for therapeutic intervention to prevent SLE progression.

Association of Osteopontin gene single nucleotide polymorphism with lupus nephritis

AIM

To determine the association of single nucleotide polymorphism at 9250 C/T in exon 7 of the Osteopontin (OPN) gene among Egyptian patients with lupus nephritis (LN) and healthy controls and assess its relation with clinical and laboratory features in addition to both activity and chronicity indices in these patients.

MATERIALS AND METHOD

The study population includes 100 patients with LN and 100 age- and gender-matched controls. OPN gene 9250 C/T polymorphism was detected by polymerase chain reaction and restriction fragment length polymorphism.

RESULTS

We observed a significant difference in the frequencies of the OPN gene 9250 T allele between the patients with LN and the controls (74.5% vs 57.5%, P < .001); also, TT and CT + TT genotypes showed significant differences in frequencies between LN patients versus controls (59% vs 35% P = .005 and 90% vs. 80% P = .048, respectively). We also observed a non-significant association between OPN gene 9250 genotypes and each of the laboratory data and clinical features in addition to activity and chronicity indices in all studied LN patients. There were no statistically significant increased TT and CT + TT genotypes and T allele frequencies in LN patients with renal failure compared to those without renal failure. Logistic regression analysis revealed that only OPN (CT + TT) genotype could predict LN development in Egyptian patients.

CONCLUSION

TT and CT + TT genotypes and T alleles of OPN 9250 are considered risk factors for LN development in Egyptian systemic lupus erythematosus patients. However, these genotypes showed no association with each laboratory data and clinical feature or activity and chronicity indices in these patients. OPN 9250 (CT + TT) genotype could be used to predict LN development in SLE.

Knockout of the KH-Type Splicing Regulatory Protein Drives Glomerulonephritis in MRL-Faslpr Mice

KH-type splicing regulatory protein (KSRP) is an RNA-binding protein that promotes mRNA decay and thereby negatively regulates cytokine expression at the post-transcriptional level. Systemic lupus erythematosus (SLE) is an autoimmune disease characterized by dysregulated cytokine expression causing multiple organ manifestations; MRL-Faslpr mice are an established mouse model to study lupus disease pathogenesis. To investigate the impact of KSRP on lupus disease progression, we generated KSRP-deficient MRL-Faslpr mice (MRL-Faslpr/KSRP-/- mice). In line with the predicted role of KSRP as a negative regulator of cytokine expression, lupus nephritis was augmented in MRL-Faslpr/KSRP-/- mice. Increased infiltration of immune cells, especially of IFN-γ producing T cells and macrophages, driven by enhanced expression of T cell-attracting chemokines and adhesion molecules, seems to be responsible for worsened kidney morphology. Reduced expression of the anti-inflammatory interleukin-1 receptor antagonist may be another reason for severe inflammation. The increase of FoxP3+ T cells detected in the kidney seems unable to dampen the massive kidney inflammation. Interestingly, lymphadenopathy was reduced in MRL-Faslpr/KSRP-/- mice. Altogether, KSRP appears to have a complex role in immune regulation; however, it is clearly able to ameliorate lupus nephritis.

Interferon Genes Are Influenced by 17β-Estradiol in SLE

Recent evidence suggests the existence of a nexus between inflammatory pathways and the female sex hormone 17β-estradiol, resulting in increased interferon-stimulated genes (ISGs), autoantibodies, and dysregulation of immune cells in SLE. However, the molecular mechanisms and the effect of estradiol on candidate target genes and their pathways remains poorly understood. Our previous work suggests that female SLE patients have increased estradiol levels compared to healthy controls. In the present study, we explored the effects of 17β-estradiol treatment on expression of IFN (interferons)-stimulated genes and pro-inflammatory cytokines/chemokines. We found significantly increased (5-10-fold) expression of IFN-regulated genes in healthy females. Furthermore, we found significantly increased plasma levels of IL-6, IL-12, IL-17, IL-18, stem cell factor (SCF), and IL-21/IL-23 in SLE patients compared to healthy controls, and those levels positively correlated with the plasma levels of 17β-estradiol. In addition, levels of IL-21 positively correlated with the SLE disease activity index (SLEDAI) score of SLE patients. In vitro treatment of PBMCs from either SLE patients or healthy controls with 17β-estradiol at physiological concentration (~50 pg/ml) also significantly increased secretion of many pro-inflammatory cytokines and chemokines (IL-6, IL-12, IL-17, IL-8, IFN-γ; MIP1α, and MIP1β) in both groups. Further our data revealed that 17β-estradiol significantly increased the percentage of CD3⁺CD69⁺ and CD3⁺IFNγ⁺ T cells; whereas, simultaneous addition of 17β-estradiol and an ERα inhibitor prevented this effect. Collectively, our findings indicate that 17β-estradiol participates in the induction of pro-inflammatory cytokines and chemokines and further influences interferon genes and pathways.

Compartmentalization of interleukin 36 subfamily according to inducible and constitutive expression in the kidneys of a murine autoimmune nephritis model

The interleukin (IL) 36 subfamily belongs to the IL-1 family and is comprised of agonists (IL-36α, IL-36β, IL-36γ) and antagonists (IL-36Ra, IL-38). We previously reported IL-36α overexpression in renal tubules of chronic nephritis mice. To understand the localization status and biological relationships among each member of the IL-36 subfamily in the kidneys, MRL/MpJ-Fas^lpr/lpr mice were investigated as autoimmune nephritis models using pathology-based techniques. MRL/MpJ-Fas^lpr/lpr mice exhibited disease onset from 3 months and severe nephritis at 6-7 months (early and late stages, respectively). Briefly, IL-36γ and IL-36Ra were constitutively expressed in murine kidneys, while the expression of IL-36α, IL-36β, IL-36Ra, and IL-38 was induced in MRL/MpJ-Fas^lpr/lpr mice. IL-36α expression was significantly increased and localized to injured tubular epithelial cells (TECs). CD44⁺-activated parietal epithelial cells (PECs) also exhibited higher IL-36α-positive rates, particularly in males. IL-36β and IL-38 are expressed in interstitial plasma cells. Quantitative indices for IL-36α and IL-38 positively correlated with nephritis severity. Similar to IL-36α, IL-36Ra localized to TECs and PECs at the late stage; however, MRL/MpJ-Fas^lpr/lpr and healthy MRL/MpJ mice possessed IL-36Ra⁺ smooth muscle cells in kidney arterial tunica media at both stages. IL-36γ was constitutively expressed in renal sympathetic axons regardless of strain and stage. IL-36 receptor gene was ubiquitously expressed in the kidneys and was induced proportional to disease severity. MRL/MpJ-Fas^lpr/lpr mice kidneys possessed significantly upregulated IL-36 downstream candidates, including NF-κB- or MAPK-pathway organizing molecules. Thus, the IL-36 subfamily contributes to homeostasis and inflammation in the kidneys, and especially, an IL-36α-dominant imbalance could strongly impact nephritis deterioration.

Interleukin-2 Deficiency Associated with Renal Impairment in Systemic Lupus Erythematosus

Impaired interleukin-2 (IL-2) production was reported in systemic lupus erythematosus (SLE). The aim of this study was to investigate the clinical relevance of serum IL-2 and therapeutic effects of recombinant IL-2 (rIL-2) in SLE, especially in lupus nephritis (LN). Decreased serum IL-2 was found in patients with active LN (P = 0.014) and correlated with 24-h urine protein excretion (r = -0.281, P = 0.026). Compared with LN patients with decreased levels of serum IL-2, patients with increased levels had better remission rate (P = 0.041). Furthermore, patients with exogenous low-dose IL-2 supplement demonstrated better improved nephritis and higher remission rate (55.56%, P = 0.058) than those with conventional therapy. In addition, the percentages of regulator T (Treg) cells expanded in LN patients with low-dose recombinant human IL-2 treatment (P = 0.007), especially in LN patients achieving remission (P = 0.010). IL-2 deficiency is associated with renal impairment that can be improved by exogenous IL-2 supplement.

An update on genetic susceptibility in lupus nephritis

Systemic lupus erythematosus (SLE) is a chronic autoimmune disease characterized by multiple system involvement and positive serum autoantibodies. Lupus nephritis (LN) is the most common and serious complication of SLE, and it is the main cause of death in patients with SLE. Abnormalities in the immune system lead to LN and involve a variety of cells (T cells, B cells, macrophages, NK cells, etc.), cytokines (interleukin, tumor necrosis factor α, etc.) and their related pathways. Previous studies have shown that the interactions of genetic, epigenetic and environmental factors contribute to the pathogenesis and development of LN. In recent years, one genome-wide association study (GWAS) and a number of gene association studies have explored the susceptibility genes of LN, including immunization-, inflammation-, adhesion- and other pathway-related genes. These genes participate in or suggest the pathogenesis and progression of LN. In this review, we summarize the genetic susceptibility of LN and discuss the possible mechanism underlying the susceptibility genes of LN.

α2AP is associated with the development of lupus nephritis through the regulation of plasmin inhibition and inflammatory responses

Introduction

Lupus nephritis (LN) is a common complication of systemic lupus erythematosus (SLE), which is a chronic autoimmune disease. However, the detailed mechanisms underlying this disorder have remained unclear. Alpha2‐antiplasmin (α2AP) is known to perform various functions, such as plasmin inhibition and cytokine production, and to be associated with immune and inflammatory responses.

Methods

We investigated the roles of α2AP in the pathogenesis of LN using a pristane‐induced lupus mouse model.

Results

The levels of plasmin‐α2AP complex and α2AP were elevated in the lupus model mice. In addition, α2AP deficiency attenuated the pristane‐induced glomerular cell proliferation, mesangial matrix expansion, collagen production, fibrin deposition, immunoglobulin G deposition, and proinflammatory cytokine production in the model mice. We also showed that interferon‐γ (IFN‐γ), which is an essential inducer of LN, induced α2AP production through the c‐Jun N‐terminal kinase (JNK) pathway in fibroblasts. In addition, plasmin attenuated the IFN‐γ‐induced proinflammatory cytokine production through the AMPK pathway in macrophages, and α2AP eliminated these effects. Furthermore, we showed that α2AP induced proinflammatory cytokine production through the ERK1/2 and JNK pathways in macrophages.

Conclusion

α2AP regulates the inflammatory responses through plasmin inhibition and proinflammatory cytokine production and is associated with the development of LN. Our findings may be used to develop a novel therapeutic approach for SLE.

The Urinary Exosomal miRNA Expression Profile is Predictive of Clinical Response in Lupus Nephritis

Data on exosomal-derived urinary miRNAs have identified several miRNAs associated with disease activity and fibrosis formation, but studies on prognosis are lacking. We conducted a qPCR array screening on urinary exosomes from 14 patients with biopsy-proven proliferative lupus glomerulonephritis with a renal outcome of clinical response (n = 7) and non-response (n = 7) following therapy. Validation studies were performed by qRT-PCR in a new lupus nephritis (LN) cohort (responders = 22 and non-responders = 21). Responder patients expressed significantly increased levels of miR-31, miR-107, and miR-135b-5p in urine and renal tissue compared to non-responders. MiR-135b exhibited the best predictive value to discriminate responder patients (area under the curve = 0.783). In vitro studies showed exosome-derived miR-31, miR-107, and miR-135b-5p expression to be mainly produced by tubular renal cells stimulated with inflammatory cytokines (e.g IL1, TNFα, IFNα and IL6). Uptake of urinary exosomes from responders by mesangial cells was superior compared to that from non-responders (90% vs. 50%, p < 0.0001). HIF1A was identified as a potential common target, and low protein levels were found in non-responder renal biopsies. HIF1A inhibition reduced mesangial proliferation and IL-8, CCL2, CCL3, and CXCL1 mesangial cell production and IL-6/VCAM-1 in endothelial cells. Urinary exosomal miR-135b-5p, miR-107, and miR-31 are promising novel markers for clinical outcomes, regulating LN renal recovery by HIF1A inhibition.

An update on genetic susceptibility in lupus nephritis

Systemic lupus erythematosus (SLE) is a chronic autoimmune disease characterized by multiple system involvement and positive serum autoantibodies. Lupus nephritis (LN) is the most common and serious complication of SLE, and it is the main cause of death in patients with SLE. Abnormalities in the immune system lead to LN and involve a variety of cells (T cells, B cells, macrophages, NK cells, etc.), cytokines (interleukin, tumor necrosis factor α, etc.) and their related pathways. Previous studies have shown that the interactions of genetic, epigenetic and environmental factors contribute to the pathogenesis and development of LN. In recent years, one genome-wide association study (GWAS) and a number of gene association studies have explored the susceptibility genes of LN, including immunization-, inflammation-, adhesion- and other pathway-related genes. These genes participate in or suggest the pathogenesis and progression of LN. In this review, we summarize the genetic susceptibility of LN and discuss the possible mechanism underlying the susceptibility genes of LN.

TNF-α promoter polymorphisms (G-238A and G-308A) are associated with susceptibility to Systemic Lupus Erythematosus (SLE) and P. falciparum malaria: a study in malaria endemic area

Tumor necrosis factor-α (TNF-α) is a proinflammatory cytokine associated with autoimmune and infectious diseases. Importance of TNF-α in P. falciparum malaria and systemic lupus erythematosus (SLE) have been demonstrated. However, association of functional promoter variants with SLE and malaria is lacking in malaria endemic population. A total of 204 female SLE patients and 224 age and sex matched healthy controls were enrolled in the study. Three hundred fourteen P. falciparum infected patients with different clinical phenotypes were included. TNF-α polymorphisms (G-238A & G-308A) were genotyped by PCR-RFLP. Plasma levels of TNF-α was quantified by ELISA. Heterozygous mutants and minor alleles of TNF-α (G-238A and G-308A) polymorphisms were significantly higher in SLE patients compared to healthy controls and associated with development of lupus nephritis. In addition, both promoter variants were associated with severe P. falciparum malaria. SLE patients demonstrated higher levels of plasma TNF-α compared to healthy controls. TNF-α (G-238A and G-308A) variants were associated with higher plasma TNF-α. In conclusion, TNF-α (G-238A & G-308A) variants are associated with higher plasma TNF-α levels in SLE patients residing in malaria endemic areas and could be a contributing factor in the development of SLE and susceptibility to severe P. falciparum malaria.

Decreased α7nAChR mRNA levels in peripheral blood monocytes are associated with enhanced inflammatory cytokine production in patients with lupus nephritis

The cholinergic anti-inflammatory pathway modulates cytokine release by activating alpha-7 nicotinic acetylcholine receptors (α7nAChR) in monocytes/macrophages. We aimed to determine the role of α7nAChR in lupus nephritis (LN). We enrolled 36 inactive and 35 active LN patients, 34 primary glomerulonephritis patients, and 35 healthy controls. Peripheral blood monocytes were isolated, and mRNA expression of α7nAChR, interleukin (IL)-1β, IL-6, IL-10, and tumor necrosis factor-alpha (TNF-α) in monocytes was measured. α7nAChR and IL-10 mRNA levels were significantly decreased, but IL-6 was increased, in LN patients compared with healthy controls or glomerulonephritis patients (all P < 0.01). Interestingly, α7nAChR mRNA levels were negatively correlated to SLEDAI (r = -0.68, P < 0.01), anti-dsDNA (r = -0.38, P < 0.05), and proteinuria (r = -0.49, P < 0.01) levels, and positively correlated to serum complement C3 levels (r = 0.38, P < 0.05) in patients with active LN. Furthermore, α7nAChR mRNA levels were negatively correlated to TNF-α (r = -0.50, P < 0.01), IL-1β (r = -0.42, P < 0.05), IL-6 (r = -0.69, P < 0.01) mRNA levels, and positively correlated to IL-10 (r = 0.45, P < 0.01). TNF-α, IL-1β, and IL-6 protein levels in the supernatant of cultured monocytes from active LN patients were significantly higher, while IL-10 was lower, than that of healthy controls. PNU-282987, an α7nAChR agonist, significantly decreased TNF-α, IL-1β, and IL-6 but increased IL-10 in the monocyte culture supernatant of active LN patients, which were abolished by an α7nAChR antagonist methyllycaconitine. The effects of PNU-282987 were confirmed in lipopolysaccharides-stimulated monocytes. Taken together, these findings suggest that decrease in α7nAChR mRNA levels may play a role in LN and that activation of α7nAChR may inhibit inflammation in LN.

Effect of a Combination of Prednisone or Mycophenolate Mofetil and Mesenchymal Stem Cells on Lupus Symptoms in MRL.Faslpr Mice

The combination of immunosuppressants and mesenchymal stem cells (MSCs) is a promising therapeutic strategy for systemic lupus erythematosus, since this approach reduces doses of immunosuppressants while maintaining the same therapeutic outcome. However, it is unavoidable for MSCs to be exposed to immunosuppressants. Here, we examined the combination effect of prednisone (PD) or mycophenolate mofetil (MMF) and MSCs. We showed that PD or MMF in combination with MSCs showed better therapeutic effect than single therapy in lupus-prone MRL.Fas^lpr mice, as assessed by using the following readouts: prolongation of survival, decrease in anti-dsDNA and total IgG levels in serum, decrease in cytokine gene expression in spleen cells, and decrease in inflammatory cell infiltration into the kidney. In vitro, immunosuppressants and MSCs inhibited T cell proliferation in a synergistic manner. However, immunosuppressants did not affect MSC viability and functions such as TGF-β1 and PGE₂ production, migration, and immunosuppressive capacity. In summary, our study demonstrates that a combination of immunosuppressants and MSCs is a good strategy to reduce the side effects of PD and MMF without the loss of therapeutic outcome.

Ligation of Na, K ATPase β3 subunit on monocytes by a specific monoclonal antibody mediates T cell hypofunction

T cells play a crucial role in orchestrating body immune responses. T cell hyperfunction, however, leads to inflammation and induction of autoimmune diseases. Understanding of T cell regulation mechanisms and successful modulation of T cell responses is beneficial in treatment of disease associated to T cell hyperresponsiveness. Our previous study indicated that monoclonal antibody (mAb) P-3E10, a mAb to Na, K ATPase β3 subunit, inhibited anti-CD3-induced PBMC proliferation. In the current study, we further investigated the mechanism of mAb P-3E10 in the induction of T cell hypofunction. We demonstrated that mAb P-3E10 decreased T cell proliferation and Th1, Th2 and Th17 cytokine production. Monocytes were the cells playing a key role in mediation of mAb P-3E10 induced T cell hypofunction. The inhibition of T cell activation by mAb P-3E10 required cell contact between monocytes and T cells. The mAb P-3E10 induced the down-expression level of MHC class II and CD86 and increased IL-6, IL-10 and TNF-α production of monocytes. We concluded that ligation of the Na, K ATPase β3 subunit on monocytes by mAb P-3E10 arbitrated T cell hypofunction. This mAb might be a promising novel immunotherapeutic antibody for the treatment of hyperresponsive T cell associated diseases.

Upregulated fractalkine levels in Chinese patients with lupus nephritis

OBJECTIVE

To investigate the expression levels of fractalkine (FKN) mRNA in peripheral blood mononuclear cells (PBMCs) and FKN protein in serum of patients with lupus nephritis (LN) from China, and to evaluate the associations between the expression of FKN and systemic lupus erythematosus disease activity index 2000 (SLEDAI-2 K), anti-double-stranded DNA and complement proteins in LN patients.

METHODS

Real-time quantitative polymerase chain reaction and enzyme-linked immunosorbent assay were used to detect the expression levels of FKN mRNA in PBMCs and FKN protein in serum separately from 105 patients with LN and 52 healthy controls.

RESULTS

Serum level and mRNA level of FKN were significantly increased in LN patients when compared to controls (P < 0.001). Higher FKN levels were found in active LN patients and LN patients with renal damage when compared with inactive LN patients and LN patients without renal damage (P < 0.001). Higher serum FKN levels were detected in inactive LN patients in comparison with healthy controls (Z = -7.165, P < 0.001). The FKN expression levels were positively correlated with SLEDAI-2 K, and was associated with the presence of autoantibodies and negatively correlated with complement proteins C3 and C4 in LN patients.

CONCLUSIONS

The results suggest that upregulation of FKN is associated with the pathogenesis and activity of LN in Chinese patients.

Involvement of TWEAK and the NF-κB signaling pathway in lupus nephritis

Previous findings have identified that tumor necrosis factor-related weak inducer of apoptosis (TWEAK) is associated with lupus nephritis (LN) activity status; however, the mechanism involved remains unclear. The present study aimed to investigate the roles of TWEAK and the nuclear factor (NF)-κB signaling pathway in LN. TWEAK levels in the blood and urine of patients with LN or non-LN systemic lupus erythematosus were measured by ELISA and compared with those in healthy controls. TWEAK expression and NF-κB transcriptional activity in the kidney were detected by western blotting, and Ki-67 and cluster of differentiation (CD) 68 expression were assessed using immunofluorescence. Additionally, human mesangial cells (HMCs) were cultured in vitro and divided into five groups: Normal control, TWEAK stimulus group, TWEAK + TWEAK blocking antibody, TWEAK + NF-κB inhibitor (BAY 11-7082) and TWEAK + combined (blocking antibody + BAY 11-7082). Cell cycle activity and Ki-67 expression in the HMCs were evaluated using flow cytometry, and cell induction of macrophage chemotaxis was determined by a Transwell assay. Levels of the inflammation-associated factors interleukin (IL)-6, monocyte chemotactic protein 1 (MCP-1), chemokine ligand 5 (CCL5), IL-8 and IL-10 were also detected by reverse transcription-quantitative polymerase chain reaction. It was observed that the urine levels of TWEAK in patients with LN were significantly elevated compared with those in the other groups (P<0.05). LN kidneys exhibited markedly increased cell proliferative ability, macrophage infiltration, TWEAK expression and NF-κB transcriptional activity compared with normal kidneys. Furthermore, the results indicated that treatment with recombinant TWEAK notably enhanced NF-κB transcriptional activity and significantly promoted cell proliferation and cell cycle activity (P<0.05), induced macrophage chemotaxis (P<0.05), significantly increased the expression of the chemotactic factors IL-6, IL-8, MCP-1 and CCL5 (P<0.05), and significantly reduced anti-inflammatory cytokine IL-10 mRNA expression in HMCs (P<0.05), relative to normal controls. Accordingly, blocking TWEAK function or inhibiting NF-κB activity reversed these effects. Collectively these data indicate that urine TWEAK may be considered as a novel biomarker of LN activity, and that blocking TWEAK function or NF-κB activity may effectively alleviate glomerular mesangial cell proliferation and macrophage chemotaxis.

ABIN1 Determines Severity of Glomerulonephritis via Activation of Intrinsic Glomerular Inflammation

Transcription factor NF-κB regulates expression of numerous genes that control inflammation and is activated in glomerular cells in glomerulonephritis (GN). We previously identified genetic variants for a NF-κB regulatory, ubiquitin-binding protein ABIN1 as risk factors for GN in systemic autoimmunity. The goal was to define glomerular inflammatory events controlled by ABIN1 function in GN. Nephrotoxic serum nephritis was induced in wild-type (WT) and ubiquitin-binding deficient ABIN1[D485N] mice, and renal pathophysiology and glomerular inflammatory phenotypes were assessed. Proteinuria was also measured in ABIN1[D485N] mice transplanted with WT mouse bone marrow. Inflammatory activation of ABIN1[D472N] (D485N homolog) cultured human-derived podocytes, and interaction with primary human neutrophils were also assessed. Disruption of ABIN1 function exacerbated proteinuria, podocyte injury, glomerular NF-κB activity, glomerular expression of inflammatory mediators, and glomerular recruitment and retention of neutrophils in antibody-mediated nephritis. Transplantation of WT bone marrow did not prevent the increased proteinuria in ABIN1[D845N] mice. Tumor necrosis factor-stimulated enhanced expression and secretion of NF-κB-targeted proinflammatory mediators in ABIN1[D472N] cultured podocytes compared with WT cells. Supernatants from ABIN1[D472N] podocytes accelerated chemotaxis of human neutrophils, and ABIN1[D472N] podocytes displayed a greater susceptibility to injurious morphologic findings induced by neutrophil granule contents. These studies define a novel role for ABIN1 dysfunction and NF-κB in mediating GN through proinflammatory activation of podocytes.

A2A adenosine receptor upregulation correlates with disease activity in patients with systemic lupus erythematosus

BACKGROUND

Adenosine is a purine nucleoside implicated in the regulation of the innate and adaptive immune systems, acting through its interaction with four cell surface receptors: A1, A2A, A2B, and A3. There is intense interest in understanding how adenosine functions in health and during disease, but surprisingly little is known about the actual role of adenosine-mediated mechanisms in systemic lupus erythematosus (SLE). With this background, the aim of the present study was to test the hypothesis that dysregulation of A1, A2A, A2B, and A3 adenosine receptors (ARs) in lymphocytes of patients with SLE may be involved in the pathogenesis of the disease and to examine the correlations between the status of the ARs and the clinical parameters of SLE.

METHODS

ARs were analyzed by performing saturation-binding assays, as well as messenger RNA and Western blot analysis, with lymphocytes of patients with SLE in comparison with healthy subjects. We tested the effect of A2AAR agonists in the nuclear factor kB (NF-kB) pathway and on the release of interferon (IFN)-α; tumor necrosis factor (TNF)-α; and interleukin (IL)-2, IL-6, IL-1β, and IL-10.

RESULTS

In lymphocytes obtained from 80 patients with SLE, A2AARs were upregulated compared with those of 80 age-matched healthy control subjects, while A1, A2B, and A3 ARs were unchanged. A2AAR density was inversely correlated with Systemic Lupus Erythematosus Disease Activity Index 2000 score disease activity through time evaluated according to disease course patterns, serositis, hypocomplementemia, and anti-double-stranded DNA positivity. A2AAR activation inhibited the NF-kB activation pathway and diminished inflammatory cytokines (IFN-α, TNF-α, IL-2, IL-6, IL-1β), but it potentiated the release of anti-inflammatory IL-10.

CONCLUSIONS

These data suggest the involvement of A2AARs in the complex pathogenetic network of SLE, acting as a modulator of the inflammatory process. It could represent a compensatory pathway to better counteract disease activity. A2AAR activation significantly reduced the release of proinflammatory cytokines while enhancing those with anti-inflammatory activity, suggesting a potential translational use of A2AAR agonists in SLE pharmacological treatment.

JAK3-STAT pathway blocking benefits in experimental lupus nephritis

Background

Lupus nephritis (LN) is a complex chronic autoimmune disease of unknown etiology characterized by loss of tolerance against several self-antigens. Cytokines are known to be central players in LN pathogenesis. The Janus kinase-signal transducer and activator of transcription (JAK-STAT) pathway is one important pathway that mediates signal transduction of several cytokines. In this study, we examined the pathogenic role of this pathway and how CP-690,550 treatment influences LN outcome.

Methods

Six-month-old NZB/NZWF1 mice were divided into two different treatment groups: (1) control animals given vehicle treatment, cyclophosphamide, and mycophenolate mofetil treatment as positive controls of the therapy and (2) mice treated with CP-690,550, a JAK3 inhibitor. Mice were treated for 12 weeks. We evaluated renal function, anti-double-stranded DNA (anti-dsDNA) antibody, renal histology changes, kidney complement and immunoglobulin G (IgG) deposits, T-cell and macrophage infiltration, kidney inflammatory gene expression, and circulating cytokine changes.

Results

CP-690,550 treatment significantly reduced proteinuria and improved renal function and histological lesions of the kidney. Compared with vehicle-treated animals, those undergoing CP-690,550 treatment showed significantly diminished anti-dsDNA antibody and complement component C3 and IgG deposition in glomeruli. We also observed a significant reduction of T-cell and macrophage infiltration. Kidney gene expression revealed a reduction in inflammatory cytokines and complement and related macrophage-attracting genes. Circulating inflammatory cytokines were also reduced with treatment.

Conclusions

On the basis of our results, we conclude that the JAK-STAT pathway is implicated in the progression of renal inflammation in NZB/WF1 mice and that targeting JAK3 with CP-690,550 is effective in slowing down the course of experimental LN. Thus, CP-690,550 could become a new therapeutic tool in LN and other autoimmune diseases.

Pathogenic Inflammation and Its Therapeutic Targeting in Systemic Lupus Erythematosus

Systemic lupus erythematosus (SLE, lupus) is a highly complex and heterogeneous autoimmune disease that most often afflicts women in their child-bearing years. It is characterized by circulating self-reactive antibodies that deposit in tissues, including skin, kidneys, and brain, and the ensuing inflammatory response can lead to irreparable tissue damage. Over many years, clinical trials in SLE have focused on agents that control B- and T-lymphocyte activation, and, with the single exception of an agent known as belimumab which targets the B-cell survival factor BAFF, they have been disappointing. At present, standard therapy for SLE with mild disease is the agent hydroxychloroquine. During disease flares, steroids are often used, while the more severe manifestations with major organ involvement warrant potent, broad-spectrum immunosuppression with cyclophosphamide or mycophenolate. Current treatments have severe and dose-limiting toxicities and thus a more specific therapy targeting a causative factor or signaling pathway would be greatly beneficial in SLE treatment. Moreover, the ability to control inflammation alongside B-cell activation may be a superior approach for disease control. There has been a recent focus on the innate immune system and associated inflammation, which has uncovered key players in driving the pathogenesis of SLE. Delineating some of these intricate inflammatory mechanisms has been possible with studies using spontaneous mouse mutants and genetically engineered mice. These strains, to varying degrees, exhibit hallmarks of the human disease and therefore have been utilized to model human SLE and to test new drugs. Developing a better understanding of the initiation and perpetuation of disease in SLE may uncover suitable novel targets for therapeutic intervention. Here, we discuss the involvement of inflammation in SLE disease pathogenesis, with a focus on several key proinflammatory cytokines and myeloid growth factors, and review the known outcomes or the potential for targeting these factors in SLE.

Methylprednisolone attenuates lipopolysaccharide-induced Fractalkine expression in kidney of Lupus-prone MRL/lpr mice through the NF-kappaB pathway

BACKGROUND

Fractalkine (FKN) is involved in the occurrence and development of human lupus nephritis. It is known to be upregulated by lipopolysaccharide (LPS) as a stimulus in vivo. MRL/lpr mice have been used as an in vivo model to study lupus nephritis. Methylprednisolone (MP) is used widely in the clinical treatment of progressive glomerular diseases such as lupus nephritis. The aim of this study is to explore the mechanism of LPS induced FKN expression and to determine whether other molecular mechanisms contribute to the signaling pathway of MP action in MRL/lpr mice.

METHODS

Forty-eight female MRL/lpr mice at 12 weeks of age were randomly distributed into six groups. Each group received various treatments for 8 weeks by receiving twice weekly intraperitoneal injections of (1) MP (MP-treated mice), of (2) SC-514 (SC-514-induced mice), of (3) normal saline and a single injection of LPS (LPS-induced mice), of (4) MP and a single injection of LPS (LPS + MP mice), of (5) SC-514 and a single injection of LPS (LPS + SC mice) and of (6) normal saline (control mice). One-way ANOVA was used for data analysis and P value <0.05 was considered statistically significantly.

RESULTS

The expression of FKN and NF-kappaB p65 mRNA was detected by qPCR. The expression of FKN protein and the activation of NF-kappaB p65 were detected by immunohistochemistry and western blots respectively. The expression of FKN in the kidney of LPS induced mice was significantly increased and this was mediated by increased expression of NF-κB p65 and an increase in NF-kappaB phospho-p65. MP reduced proteinuria and ameliorated the renal damage in MRL/lpr mice. MP as well as the NF-kappaB inhibitor, SC-514, inhibited the LPS-induced increase of expression of FKN and the activation of NF-kappaB.

CONCLUSIONS

The results indicate that MP attenuates LPS-induced FKN expression in kidney of MRL/lpr mice through the NF-kappaB pathway.

Radical improvement of signs and symptoms in systemic lupus erythematosus when treated with hemodiafiltration with endogenous reinfusion dialysis

Lupus nephritis is one of the most serious complications of systemic lupus erythematosus (SLE). In the kidney, immune complexes and autoantibodies activate mesangial cells that secrete cytokines that can further amplify inflammatory processes. We present the case of a 42-year-old woman with lupus nephritis accompanied by periods of exacerbation of SLE, with necrotic-like skin lesions, psoriatic arthritis without skin psoriasis, purpura of the lower limb, petechial rash, joint pain, fever, eyelid edema with bilateral conjunctival hyperemia and itching. The patient underwent a dialytic treatment of hemodiafiltration with endogenous reinfusion. The technique uses the super-high-flux membrane Synclear 02 (SUPRA treatment) coupled with an adsorbent cartridge that has affinity for many toxins and mediators. Fever and joint pain were immediately reduced after treatment and, subsequently, there was a notable reduction of the skin damage. Prednisone and immunosuppressive drugs were gradually reduced until complete suspension. High-performance liquid chromatography coupled with quadrupole time-of-flight mass spectrometer was performed for identification of proteins captured by a resin bed during a dialysis session of the patient. This technique identified several biomarkers of kidney injuries, uremic toxins, fragments of immunoglobulins, antigens involved in antiphospholipid syndrome and a new marker (α-defensin) that correlated significantly with disease activity. The removal of these different proteins could possibly provide an explanation of the improvement in the patient's symptoms and the normalization of her SLE. SUPRA coupled with an adsorption may be a promising new technique for the treatment of lupus nephritis.

Soluble fas and the -670 polymorphism of fas in lupus nephritis

This study was performed to clarify the role of soluble Fas (sFas) in lupus nephritis (LN) and establish a potential relationship between LN and the −670 polymorphism of Fas in 67 patients with systemic lupus erythematosus (SLE), including a subset of 24 LN patients with proteinuria. Additionally, a group of 54 healthy subjects (HS) was included. The allelic frequency of the −670 polymorphism of Fas was determined using PCR-RFLP analysis, and sFas levels were assessed by ELISA. Additionally, the WT-1 protein level in urine was measured. The Fas receptor was determined in biopsies by immunohistochemistry (IHC) and in situ hybridization (FISH) and apoptotic features by TUNEL. Results. The −670 Fas polymorphism showed that the G allele was associated with increased SLE susceptibility, with an odds ratio (OR) of 1.86. The sFas was significantly higher in LN patients with the G/G genotype, and this subgroup exhibited correlations between the sFas level and proteinuria and increased urinary WT-1 levels. LN group shows increased expression of Fas and apoptotic features. In conclusion, our results indicate that the G allele of the −670 polymorphism of Fas is associated with genetic susceptibility in SLE patients with elevated levels of sFas in LN with proteinuria.

The PTEN/PI3K/Akt signaling pathway mediates HMGB1-induced cell proliferation by regulating the NF-κB/cyclin D1 pathway in mouse mesangial cells

Our previous experiment confirmed that high-mobility group box chromosomal protein 1 (HMGB1) was involved in the pathogenesis of Lupus nephritis (LN) by upregulating the proliferation of the mouse mesangial cell line (MMC) through the cyclin D1/CDK4/p16 system, but the precise mechanism is still unknown. Therefore, in the present study, we demonstrated that HMGB1 induced the proliferation of MMC cells in a time- and concentration-dependent manner, downregulated phosphatase and tensin homolog deleted on chromosome ten (PTEN) expression, increased the level of Akt serine 473 phosphorylation, and induced p65 subunit nuclear translocation. The overexpression of PTEN prevented the upregulation of HMGB1-induced proliferation by blocking the activation of Akt. The knockdown of Akt by siRNA technology and blocking the nuclear factor-κB (NF-κB) pathway using pyrrolidine dithiocarbamate (PDTC) and SN50, inhibitors of NF-κB, both attenuated the HMGB1-induced proliferation by counteracting the activation of the cyclin D1. In addition, while sh-Akt partly blocked the nuclear translocation of the p65 subunit, PDTC did not affect the activation of the Akt induced by HMGB1 in MMC cells. These findings indicate that HMGB1 induced the proliferation of MMC cells by activating the PTEN/phosphoinositide-3-kinase (PI3K)/Akt/NF-κB signaling pathway.

Effect of nonmyeloablative unrelated fetal and neonatal murine peripheral blood mononuclear cell infusion on MRL/lpr mice

For patients with refractory systemic lupus erythematosus (SLE), current medications are insufficient to control their condition, and new treatments are necessary. We investigated the effect of fetal and neonatal murine peripheral blood (FNPB) mononuclear cells on MRL/lpr lupus-prone mice. Female MRL/lpr mice were randomized to three groups (control, radiation and infusion groups). The infusion group had significantly better results for survival rate, body weight increase, reduction of spleen index, serum anti-ds-DNA antibody, antinuclear antibodies (ANA) and creatinine (Cr), 24 h urine protein and pathological renal tissue lesions than either the control or radiation group. Graft versus host disease (GVHD) was not observed in MRL/lpr mice in the infusion group. The infusion group also had better hematogenesis reconstruction than the radiation group. Flow cytometry analysis revealed a significant increase in Th1, CD8+ T and T reg cells and a reduction in Th2, CD4+ T and Th17 cells in the peripheral blood of the radiation and infusion groups compared with the control group. Immunocytochemical assay revealed a significant increase in serum transforming growth factor (TGF)-β and a significant reduction in interleukin (IL)-17 in the radiation and infusion groups compared with the control group. Therefore, our study showed that FNPB mononuclear cell infusion has a significant role in regulating CD4+ T cells, Th1/Th2, Th17/T reg balance and their corresponding cytokines in MRL/lpr mice. The FNPB mononuclear cell infusion provided evidence in animals and suggested a potential clinical application for umbilical cord blood transplantation to treat SLE patients.

The serum levels of connective tissue growth factor in patients with systemic lupus erythematosus and lupus nephritis

OBJECTIVE

The expression of connective tissue growth factor mRNA in human kidneys may serve as an early marker for lupus nephritis progression. Therefore, we speculated that connective tissue growth factor may be involved in the pathogenesis of systemic lupus erythematosus and lupus nephritis. In this study, we set out to investigate the associations between serum connective tissue growth factor levels and clinicopathological features of patients with systemic lupus erythematosus and lupus nephritis.

METHODS

Serum samples from patients with non-renal systemic lupus erythematosus, renal biopsy-proven lupus nephritis and healthy control subjects were detected by enzyme-linked immunosorbent assay for serum connective tissue growth factor levels. The associations between connective tissue growth factor levels and clinicopathological features of the patients were further analysed.

RESULTS

The levels of serum connective tissue growth factor in patients with non-renal systemic lupus erythematosus and lupus nephritis were both significantly higher than those in the normal control group (34.14 ± 12.17 ng/ml vs. 22.8 ± 3.0 ng/ml, p<0.001; 44.1 ± 46.8 ng/ml vs. 22.8 ± 3.0 ng/ml, p = 0.035, respectively). There was no significant difference of the serum connective tissue growth factor levels between non-renal systemic lupus erythematosus and lupus nephritis group (34.14 ± 12.17 ng/ml vs. 44.1 ± 46.8 ng/ml, p = 0.183). Serum connective tissue growth factor levels were significantly higher in lupus nephritis patients with the following clinical manifestations, including anaemia (51.3 ± 51.4 ng/ml vs. 23.4 ± 9.7 ng/ml, p<0.001) and acute renal failure (85.5 ± 75.0 ng/ml vs. 31.2 ± 21.8 ng/ml, p = 0.002). Serum connective tissue growth factor levels in class IV were significantly higher than that in class II, III and V (57.6 ± 57.5 ng/ml vs. 18.7 ± 6.4 ng/ml, p = 0.019; 57.6 ± 57.5 ng/ml vs. 25.2 ± 14.9 ng/ml, p = 0.006; 57.6 ± 57.5 ng/ml vs. 30.5 ± 21.3 ng/ml, p = 0.017, respectively). Serum connective tissue growth factor levels were significantly higher in those with both active/chronic lesions than those in those with active lesions only in either class IV (84.9 ± 69.6 ng/ml vs. 40.0 ± 40.2 ng/ml, p = 0.001) or in combination of class III and IV lupus nephritis (63.3 ± 63.4 ng/ml vs. 38.3 ± 37.9 ng/ml, p = 0.035, respectively). Serum connective tissue growth factor levels were negatively associated with estimated glomerular filtration rate (r = -0.46, p<0.001) and positively associated with interstitial inflammation (r = 0.309, p = 0.002) and interstitial fibrosis (r = 0.287, p = 0.004). Serum connective tissue growth factor level was a risk factor for doubling of serum creatinine in lupus nephritis (p<0.001, hazard ratio = 1.015, 95% confidence intervals 1.008-1.022) in univariate analysis.

CONCLUSIONS

Serum connective tissue growth factor levels were significantly higher in lupus and correlated with chronic renal interstitial injury and doubling of serum creatinine in patients with lupus nephritis.

Association of STAT4 polymorphism with severe renal insufficiency in lupus nephritis

Lupus nephritis is a cause of significant morbidity in systemic lupus erythematosus (SLE) and its genetic background has not been completely clarified. The aim of this investigation was to analyze single nucleotide polymorphisms (SNPs) for association with lupus nephritis, its severe form proliferative nephritis and renal outcome, in two Swedish cohorts. Cohort I (n = 567 SLE cases, n = 512 controls) was previously genotyped for 5676 SNPs and cohort II (n = 145 SLE cases, n = 619 controls) was genotyped for SNPs in STAT4, IRF5, TNIP1 and BLK. Case-control and case-only association analyses for patients with lupus nephritis, proliferative nephritis and severe renal insufficiency were performed. In the case-control analysis of cohort I, four highly linked SNPs in STAT4 were associated with lupus nephritis with genome wide significance with p = 3.7 × 10(-9), OR 2.20 for the best SNP rs11889341. Strong signals of association between IRF5 and an HLA-DR3 SNP marker were also detected in the lupus nephritis case versus healthy control analysis (p <0.0001). An additional six genes showed an association with lupus nephritis with p <0.001 (PMS2, TNIP1, CARD11, ITGAM, BLK and IRAK1). In the case-only meta-analysis of the two cohorts, the STAT4 SNP rs7582694 was associated with severe renal insufficiency with p = 1.6 × 10(-3) and OR 2.22. We conclude that genetic variations in STAT4 predispose to lupus nephritis and a worse outcome with severe renal insufficiency.

A novel autoantibody against moesin in the serum of patients with MPO-ANCA-associated vasculitis

BACKGROUND

Antineutrophil cytoplasmic autoantibody (ANCA) directed against myeloperoxidase (MPO), a diagnostic criterion in MPO-ANCA-associated vasculitis (MPO-AAV), does not always correlate with disease activity. Here, we detected autoantibodies against moesin, which was located on the surface of stimulated endothelial cells, in the serum of patients.

METHODS

The anti-moesin autoantibody titer was evaluated by ELISA. Seventeen kinds of cytokines/chemokines were measured by a Bio-Plex system.

RESULTS

Serum creatinine in the anti-moesin autoantibody-positive group was higher than that in the negative group. Additionally, interferon (IFN)-γ, macrophage chemotactic peptide-1 (MCP-1), interleukin (IL)-2, IL-7, IL-12p70, IL-13, granulocyte/macrophage colony-stimulating factor (GM-CSF) and granulocyte colony-stimulating factor were significantly higher in the positive group. Furthermore, IL-7 and IL-12p70 levels correlated with the anti-moesin autoantibody titer. Based on these findings and the binding of anti-moesin IgG to neutrophils and monocytes, we detected the secretion of cytokines/chemokines such as IFN-γ, MCP-1 and GM-CSF from these cells.

CONCLUSIONS

The anti-moesin autoantibody existed in the serum of patients with MPO-AAV and was associated with the production of inflammatory cytokines/chemokines targeting neutrophils with a cytoplasmic profile, which suggests that the anti-moesin autoantibody has the possibility to be a novel autoantibody developing vasculitis via neutrophil and endothelial cell activation.

Kallikrein transduced mesenchymal stem cells protect against anti-GBM disease and lupus nephritis by ameliorating inflammation and oxidative stress

Previously we have shown that kallikreins (klks) play a renoprotective role in nephrotoxic serum induced nephritis. In this study, we have used mesenchymal stem cells (MSCs) as vehicles to deliver klks into the injured kidneys and have measured their therapeutic effect on experimental antibody induced nephritis and lupus nephritis. Human KLK-1 (hKLK1) gene was transduced into murine MSCs using a retroviral vector to generate a stable cell line, hKLK1-MSC, expressing high levels of hKLK1. 129/svj mice subjected to anti-GBM induced nephritis were transplanted with 10⁶ hKLK1-MSCs and hKLK1 expression was confirmed in the kidneys. Compared with vector-MSCs injected mice, the hKLK1-MSCs treated mice showed significantly reduced proteinuria, blood urea nitrogen (BUN) and ameliorated renal pathology. Using the same strategy, we treated lupus-prone B6.Sle1.Sle3 bicongenic mice with hKLK1-MSCs and demonstrated that hKLK1-MSCs delivery also attenuated lupus nephritis. Mechanistically, hKLK1-MSCs reduced macrophage and T-lymphocyte infiltration into the kidney by suppressing the expression of inflammation cytokines. Moreover, hKLK1 transduced MSCs were more resistant to oxidative stress-induced apoptosis. These findings advance genetically modified MSCs as potential gene delivery tools for targeting therapeutic agents to the kidneys in order to modulate inflammation and oxidative stress in lupus nephritis.