ABSTRACT
OBJECTIVE: Lupus nephritis (LN) is a major determinant of morbidity and mortality in systemic lupus erythematosus (SLE). Pim-1 regulates lymphocyte proliferation and activation. The role of Pim-1 in autoimmune disease remains unclear. This study was undertaken to test the hypothesis that inhibition of Pim-1 would have therapeutic potential in patients with LN. METHODS: Pim-1 expression was analyzed in lupus-prone (NZB × NZW)F1 mice (n = 6), human peripheral blood mononuclear cells (PBMCs) from SLE patients (n = 10), and glomeruli from patients with LN (n = 8). The therapeutic effect of the Pim-1 inhibitor AZD1208 was assessed in the same murine lupus model (n = 10 mice per group). In vitro analysis was conducted to explore the mechanisms of action of Pim-1 in mouse and human podocytes after Pim-1 expression had been induced by anti-double-stranded DNA (anti-dsDNA) antibody-positive serum. Finally, MRL/lpr mice were used to confirm the therapeutic effects of Pim-1 inhibition in vivo (n = 10 mice per group). RESULTS: Up-regulation of Pim-1 was seen in renal lysates from diseased (NZB × NZW)F1 mice and in PBMCs from patients with SLE and renal biopsy tissue from patients with LN, relative to their control counterparts (each P < 0.05). The Pim-1 inhibitor AZD1208 reduced the severity of proteinuria, glomerulonephritis, renal immune complex deposits, and serum anti-dsDNA antibody levels, concomitant with the suppression of NFATc1 expression and NLRP3 inflammasome activation, in diseased (NZB × NZW)F1 mice (each P < 0.05 versus controls). Moreover, in mouse and human podocytes, Pim-1 knockdown with targeted small interfering RNA (siRNA) suppressed NFATc1 and NLRP3 inflammasome signaling in the presence of anti-dsDNA-positive serum (each P < 0.05 versus control siRNA). Mechanistically, Pim-1 modulated NLRP3 inflammasome activation through intracellular Ca2+ (P < 0.05 versus normal controls). The therapeutic effect of Pim-1 blockade was replicated in MRL/lpr mice. CONCLUSION: These data identify Pim-1 as a critical regulator of LN pathogenesis in patients with SLE. Targeting of the Pim-1/NFATc1/NLRP3 pathway might therefore have therapeutic potential in human LN.
Subject(s)
Cell Proliferation/drug effects , Lupus Erythematosus, Systemic/complications , Lupus Nephritis/drug therapy , Lymphocyte Activation/drug effects , Proto-Oncogene Proteins c-pim-1/pharmacology , Animals , Antibodies, Antinuclear/immunology , Disease Models, Animal , Humans , Inflammasomes/drug effects , Kidney/cytology , Kidney Glomerulus/metabolism , Leukocytes, Mononuclear , Lupus Erythematosus, Systemic/immunology , Lupus Nephritis/immunology , Mice , Mice, Inbred MRL lpr , NFATC Transcription Factors/drug effects , NLR Family, Pyrin Domain-Containing 3 Protein/drug effects , Podocytes/metabolism , Proto-Oncogene Proteins c-pim-1/immunology , Signal Transduction/drug effectsABSTRACT
Despite rapid progress in the understanding of systemic lupus erythematosus (SLE), there is still an urgent need for novel and more effective interventions. Curcumin, a natural polyphenol compound, has been shown to be anti-inflammatory in various disorders. In this study, we investigated the potential therapeutic value of curcumin in SLE. Lupus-prone female MRL/lpr mice were treated with curcumin. The development and extent of nephritis were assessed by monitoring proteinuria and by histologic analysis. Serum anti-dsDNA levels were measured by enzyme-linked immunosorbent assay. Kidney samples were analyzed by Western blot. In vitro, mouse podocytes were used for investigation in the presence of mouse anti-dsDNA antibody-positive (anti-dsDNA+) serum. Curcumin treatment dramatically decreased proteinuria and renal inflammation. Serum anti-dsDNA levels and spleen size were also reduced by curcumin. In addition, curcumin reduced NLRP3 inflammasome activation in lupus-prone mice. In vitro, curcumin significantly inhibited anti-dsDNA+ serum induced expression of NLRP3 inflammasome in podocytes. Overall, these data demonstrate the potential use of curcumin in SLE treatment.
Subject(s)
Anti-Inflammatory Agents/therapeutic use , Curcumin/therapeutic use , Inflammasomes/drug effects , Kidney/drug effects , Lupus Erythematosus, Systemic/drug therapy , Lupus Nephritis/drug therapy , Podocytes/drug effects , Animals , Antibodies, Antinuclear/blood , Cells, Cultured , Disease Models, Animal , Female , Humans , Inflammasomes/metabolism , Kidney/immunology , Mice , Mice, Inbred MRL lpr , NLR Family, Pyrin Domain-Containing 3 Protein/metabolism , Podocytes/physiology , ProteinuriaABSTRACT
N-acetyl-seryl-aspartyl-lysyl-proline (Ac-SDKP) is an endogenous tetrapeptide which can inhibit the differentiation, migration and activation of macrophages and suppress the proliferation of fibroblast. This study examined the effects of Ac-SDKP on the progression of lupus nephritis (LN). MRL/lpr mice received subcutaneous infusion of Ac-SDKP (1.0 mg kg(-1) d(-1)) or vehicle through implanted osmotic mini-pumps from 12 to 20 weeks until being euthanized. MRL/MpJ mice served as normal controls. The data indicative of renal inflammation and fibrosis were evaluated before and after treatment. Ac-SDKP-treated MRL/lpr mice showed reduced proteinuria and improved renal function compared with vehicle-treated controls. Ac-SDKP-treated mice demonstrated decreased inflammatory infiltrates of T cells and macrophages in the kidneys as compared to vehicle-treated animals. The treatment also inhibited the activation of NF-κB and production of TNF-α. Despite this, immune complex deposition and plasma anti-dsDNA levels were not statistically different between the two groups. In addition, the treatment inhibited renal expression of TGF-ß1, α-SMA and fibronectin as well as the phosphorylation of Smad2/3. Ac-SDKP treatment ameliorated LN through exerting anti-inflammatory and anti-fibrotic effects on MRL/lpr mice, providing therapeutic potential for halting the progression of LN.
Subject(s)
Lupus Nephritis/drug therapy , Oligopeptides/therapeutic use , Actins/genetics , Actins/metabolism , Animals , Antibodies, Antinuclear , Body Weight , Chemokine CCL2/genetics , Chemokine CCL2/metabolism , Drug Administration Schedule , Female , Fibronectins/genetics , Fibronectins/metabolism , Gene Expression Regulation/drug effects , Inflammation/drug therapy , Kidney/pathology , Leukocytes , Lupus Nephritis/pathology , Mice , Mice, Inbred MRL lpr , NF-kappa B/genetics , NF-kappa B/metabolism , Oligopeptides/blood , Transforming Growth Factor beta/genetics , Transforming Growth Factor beta/metabolism , Tumor Necrosis Factor-alpha/genetics , Tumor Necrosis Factor-alpha/metabolismABSTRACT
BACKGROUND/AIMS: Inflammation is implicated in the pathogenesis of diabetic nephropathy (DN). This study examined the role of Toll-like receptor 2 (TLR2) in the progression of renal injury in a model of rat DN. METHODS: DN was induced by intravenous injection of streptozotocin and rats were sacrificed at week 2, 4 and 8. Functional and pathologic markers, inflammatory infiltration, expression of TLR2, MCP-1, MyD88, HSP70, HMGB1 and activation of NF-kappaB were assessed. The effects of glucose on the expression of TLR2 by renal tubular epithelial cells were also examined in vitro. RESULTS: The expression of TLR2 mRNA and protein level was significantly upregulated in the kidneys of diabetic rats (p < 0.01), which was associated with increased renal expression of MyD88 and MCP-1, activation of NF-kappaB and infiltration of macrophages. The expression of HSP70 and HMGB1, endogenous ligands of TLRs, was also significantly upregulated in the kidneys of diabetic rats. In human renal biopsy of DN, there was prominent expression of TLR2 in both the glomeruli and tubulointerstitium. In vitro study showed that high glucose induced the expression of TLR2 mRNA by NRK-52E cells (p < 0.01). CONCLUSIONS: Enhanced renal expression of TLR2 is associated with inflammatory infiltration in DN.
