Interferon and B-cell Signatures Inform Precision Medicine in Lupus Nephritis

Introduction

Current therapeutic management of lupus nephritis (LN) fails to induce long-term remission in over 50% of patients, highlighting the urgent need for additional options.

Methods

We analyzed differentially expressed genes (DEGs) in peripheral blood from patients with active LN (n = 41) and active nonrenal lupus (n = 62) versus healthy controls (HCs) (n = 497) from the European PRECISESADS project (NTC02890121), and dysregulated gene modules in a discovery (n = 26) and a replication (n = 15) set of active LN cases.

Results

Replicated gene modules qualified for correlation analyses with serologic markers, and regulatory network and druggability analysis. Unsupervised coexpression network analysis revealed 20 dysregulated gene modules and stratified the active LN population into 3 distinct subgroups. These subgroups were characterized by low, intermediate, and high interferon (IFN) signatures, with differential dysregulation of the "B cell" and "plasma cells/Ig" modules. Drugs annotated to the IFN network included CC-motif chemokine receptor 1 (CCR1) inhibitors, programmed death-ligand 1 (PD-L1) inhibitors, and irinotecan; whereas the anti-CD38 daratumumab and proteasome inhibitor bortezomib showed potential for counteracting the "plasma cells/Ig" signature. In silico analysis demonstrated the low-IFN subgroup to benefit from calcineurin inhibition and the intermediate-IFN subgroup from B-cell targeted therapies. High-IFN patients exhibited greater anticipated response to anifrolumab whereas daratumumab appeared beneficial to the intermediate-IFN and high-IFN subgroups.

Conclusion

IFN upregulation and B and plasma cell gene dysregulation patterns revealed 3 subgroups of LN, which may not necessarily represent distinct disease phenotypes but rather phases of the inflammatory processes during a renal flare, providing a conceptual framework for precision medicine in LN.

Transcription Factors in the Pathogenesis of Lupus Nephritis and Their Targeted Therapy

Systemic lupus erythematosus (SLE) is a prototype inflammatory autoimmune disease, characterized by breakdown of immunotolerance to self-antigens. Renal involvement, known as lupus nephritis (LN), is one of the leading causes of morbidity and a significant contributor to mortality in SLE. Despite current pathophysiological advances, further studies are needed to fully understand complex mechanisms underlying the development and progression of LN. Transcription factors (TFs) are proteins that regulate the expression of genes and play a crucial role in the development and progression of LN. The mechanisms of TF promoting or inhibiting gene expression are complex, and studies have just begun to reveal the pathological roles of TFs in LN. Understanding TFs in the pathogenesis of LN can provide valuable insights into this disease's mechanisms and potentially lead to the development of targeted therapies for its management. This review will focus on recent findings on TFs in the pathogenesis of LN and newly developed TF-targeted therapy in renal inflammation.

Increased binding of anti-dsDNA antibodies to short oligonucleotides modified with topoisomerase I reveals a potential new enzyme function independent from DNA relaxation

OBJECTIVE

Topoisomerase I (topo I) is a highly conserved enzyme which is known to reduce torsional stress at double-stranded (ds) DNA. Torsional stress induced by supercoiling of dsDNA requires either very long dsDNA existing in genomic DNA or circulation as presented in plasmid DNA. To enable DNA relaxation, topo I induce a transient single-strand break followed by stress-relieving rotation of the released DNA strand. Our group found by serendipity that the topo I inhibitor irinotecan is able to suppress murine systemic lupus erythematosus (SLE), an autoimmune disease which is characterized by the existence of pathogenic anti-dsDNA antibodies (abs). As a possible mechanism we demonstrated in the absence of immunosuppression an increased binding of anti-dsDNA abs to long genomic or circulated plasmid dsDNA modified with topo I.

RESULTS

Here we show that this effect requires active site tyrosine of topo I which is known to facilitate DNA relaxation activity. Moreover, topo I enhanced anti-dsDNA abs binding to short linear oligonucleotides down to a size of 42 bp. Since oligonucleotides of such length are devoid of torsional stress and relaxation respectively, our results suggest a new and unknown function for the enzyme topo I.

Distinct gene dysregulation patterns herald precision medicine potentiality in systemic lupus erythematosus

OBJECTIVES

We aimed at investigating the whole-blood transcriptome, expression quantitative trait loci (eQTLs), and levels of selected serological markers in patients with SLE versus healthy controls (HC) to gain insight into pathogenesis and identify drug targets.

METHODS

We analyzed differentially expressed genes (DEGs) and dysregulated gene modules in a cohort of 350 SLE patients and 497 HC from the European PRECISESADS project (NTC02890121), split into a discovery (60%) and a replication (40%) set. Replicated DEGs qualified for eQTL, pathway enrichment, regulatory network, and druggability analysis. For validation purposes, a separate gene module analysis was performed in an independent cohort (GSE88887).

RESULTS

Analysis of 521 replicated DEGs identified multiple enriched interferon signaling pathways through Reactome. Gene module analysis yielded 18 replicated gene modules in SLE patients, including 11 gene modules that were validated in GSE88887. Three distinct gene module clusters were defined i.e., "interferon/plasma cells", "inflammation", and "lymphocyte signaling". Predominant downregulation of the lymphocyte signaling cluster denoted renal activity. By contrast, upregulation of interferon-related genes indicated hematological activity and vasculitis. Druggability analysis revealed several potential drugs interfering with dysregulated genes within the "interferon" and "PLK1 signaling events" modules. STAT1 was identified as the chief regulator in the most enriched signaling molecule network. Drugs annotated to 15 DEGs associated with cis-eQTLs included bortezomib for its ability to modulate CTSL activity. Belimumab was annotated to TNFSF13B (BAFF) and daratumumab was annotated to CD38 among the remaining replicated DEGs.

CONCLUSIONS

Modulation of interferon, STAT1, PLK1, B and plasma cell signatures showed promise as viable approaches to treat SLE, pointing to their importance in SLE pathogenesis.

Multi-ancestry and multi-trait genome-wide association meta-analyses inform clinical risk prediction for systemic lupus erythematosus

Systemic lupus erythematosus is a heritable autoimmune disease that predominantly affects young women. To improve our understanding of genetic etiology, we conduct multi-ancestry and multi-trait meta-analysis of genome-wide association studies, encompassing 12 systemic lupus erythematosus cohorts from 3 different ancestries and 10 genetically correlated autoimmune diseases, and identify 16 novel loci. We also perform transcriptome-wide association studies, computational drug repurposing analysis, and cell type enrichment analysis. We discover putative drug classes, including a histone deacetylase inhibitor that could be repurposed to treat lupus. We also identify multiple cell types enriched with putative target genes, such as non-classical monocytes and B cells, which may be targeted for future therapeutics. Using this newly assembled result, we further construct polygenic risk score models and demonstrate that integrating polygenic risk score with clinical lab biomarkers improves the diagnostic accuracy of systemic lupus erythematosus using the Vanderbilt BioVU and Michigan Genomics Initiative biobanks.

Refractory mixed proliferative and membranous lupus nephritis treated with the topoisomerase I inhibitor irinotecan as add-on therapy

OBJECTIVE

To evaluate the safety and effects of irinotecan, an inhibitor of topoisomerase I, on refractory lupus nephritis.

METHOD

A patient with refractory lupus nephritis under medication with mycophenolic acid, prednisolone, and hydroxychloroquine was treated with add-on low-dose irinotecan. Irinotecan was applied every fourth week at a dose of 50 mg/m² for four cycles followed by 100 mg/m² for another eight cycles. Renal function and anti-double-stranded DNA antibodies as well as blood count for evaluation of side effects were assessed during the treatment with irinotecan.

RESULTS

Before starting the treatment with irinotecan, a urine protein/creatinine ratio of 1298 mg/g was determined. This declined to 613 mg/g after four cycles with 50 mg/m² irinotecan and was further reduced to 198 mg/g when using the higher dose of irinotecan. Kidney function remained stable, with creatinine levels of 1.66 mg/dL at the beginning and 1.76 mg/dL at the end of treatment with irinotecan. Importantly, no side effects, such as diarrhoea or neutropenia, were observed during the entire course of treatment.

CONCLUSION

Administration of low-dose irinotecan as add-on medication for the treatment of refractory lupus nephritis was shown to be safe. Clinical trials are needed to determine whether irinotecan can improve kidney function and the outcome of patients with refractory lupus nephritis.

Complete Remission of Lupus Nephritis Following Chemoradiotherapy of Carcinoma Cervix: An Association

Systemic lupus erythematosus (SLE) is associated with a higher incidence of solid organ malignancies, including cervical carcinoma, creating a paradox in their management in the context of autoimmunity. We present a case of 45-year-old female presented with mucocutaneous, musculoskeletal symptoms of SLE. Renal biopsy showed class IV lupus nephritis (LN); modified NIH activity score: 8/24, chronicity score: 6/12. Post NIH regimen induction, she achieved partial remission; further developed proteinuric relapse which was re-induced with mycophenolate mofetil (MMF) to which she failed to respond. Subsequently diagnosed with carcinoma cervix stage IIB, she received four cycles of concurrent cisplatin-based chemoradiotherapy. MMF was stopped; low dose steroids continued. Following this, the patient achieved complete remission (CR) of LN and is in remission for 5 years. This is an unexpected association between chemoradiotherapy of cervical carcinoma and CR of class IV LN, allowing long-term discontinuation of immunosuppression.

Irinotecan and its metabolite SN38 inhibits procollagen I production of dermal fibroblasts from Systemic Sclerosis patients

Systemic sclerosis (SSc) is a rare autoimmune connective tissue disease characterized by a microangiopathy and fibrosis of the skin and internal organs. No treatment has been proved to be efficient in case of early or advanced SSc to prevent or reduce fibrosis. There are strong arguments for a key role of topo-I in the pathogenesis of diffuse SSc. Irinotecan, a semisynthetic derivative of Camptothecin, specifically target topo-I. This study was undertaken to evaluate the effects of noncytotoxic doses of irinotecan or its active metabolite SN38 on collagen production in SSc fibroblasts. Dermal fibroblasts from 4 patients with SSc and 2 healthy donors were cultured in the presence or absence of irinotecan or SN38. Procollagen I release was determined by ELISA and expression of a panel of genes involved in fibrosis was evaluated by qRT-PCR. Subcytotoxic doses of irinotecan and SN38 caused a significant and dose-dependent decrease of the procollagen I production in dermal fibroblasts from SSc patients, respectively − 48 ± 3%, p < 0.0001 and − 37 ± 6.2%, p = 0.0097. Both irinotecan and SN38 led to a global downregulation of genes involved in fibrosis such as COL1A1, COL1A2, MMP1 and ACTA2 in dermal fibroblasts from SSc patients (respectively − 27; − 20.5; − 30.2 and − 30% for irinotecan and − 61; − 55; − 50 and − 54% for SN38). SN38 increased significantly CCL2 mRNA level (+ 163%). The inhibitory effect of irinotecan and its active metabolite SN38 on collagen production by SSc fibroblasts, which occurs through regulating the levels of expression of genes mRNA, suggests that topoisomerase I inhibitors may be effective in limiting fibrosis in such patients.

Camptothecin and Topotecan, Inhibitors of Transcription Factor Fli-1 and Topoisomerase, Markedly Ameliorate Lupus Nephritis in (NZB × NZW)F1 Mice and Reduce the Production of Inflammatory Mediators in Human Renal Cells

OBJECTIVE

To examine the therapeutic effects of camptothecin (CPT) and topotecan (TPT), inhibitors of transcription factor Fli-1 and topoisomerase, on lupus nephritis in (NZB × NZW)F1 (NZBWF1) mice, and to examine the effects of CPT and TPT on inflammatory mediators in human renal cells.

METHODS

Female NZBWF1 mice were treated with vehicle, cyclophosphamide (CYC), CPT (1 mg/kg or 2 mg/kg), or TPT (0.03 mg/kg, 0.1 mg/kg, or 0. 3 mg/kg) by intraperitoneal injection twice a week, beginning at the age of 25 weeks (n = 8-10 mice per group). Blood and urine were collected for monitoring autoantibodies and proteinuria. Mice were euthanized at 40 weeks, and renal pathology scores were assessed. Human renal endothelial and mesangial cells were treated with CPT or TPT, and cytokine expression was measured.

RESULTS

None of the NZBWF1 mice treated with 1 mg/kg or 2 mg/kg of CPT or 0.3 mg/kg of TPT had proteinuria >100 mg/dl at the age of 40 weeks. One of 8 mice treated with 0.1 mg/kg of TPT and 1 of 10 mice treated with CYC had proteinuria >300 mg/dl, whereas 90% of the mice treated with vehicle had proteinuria >300 mg/dl. Compared to vehicle control, mice treated with 1 mg/kg or 2 mg/kg of CPT, 0.1 mg/kg or 0.3 mg/kg of TPT, or CYC had significantly prolonged survival, attenuated renal injury, diminished splenomegaly, reduced anti-double-stranded DNA autoantibody levels, and reduced IgG and C3 deposits in the glomeruli (all P < 0.05). Human renal cells treated with CPT or TPT had reduced expression of Fli-1 and decreased monocyte chemotactic protein 1 production following stimulation with interferon-α (IFNα) or IFNγ.

CONCLUSION

Our findings indicate that low-dose CPT and TPT could be repurposed to treat lupus nephritis.

Curcumin attenuates autoimmunity and renal injury in an experimental model of systemic lupus erythematosus

Systemic lupus erythematosus (SLE) is an autoimmune disorder with prevalent hypertension and renal disease. To avoid side effects of immunosuppressive drugs, alternative therapies are needed. Curcumin has been used in Eastern medicine for its anti‐inflammatory and antioxidant properties. This study tested whether oral curcumin administration attenuates autoimmunity and renal injury during SLE. Female NZBWF1 (model of SLE) and NZW/LacJ (control) mice were administered curcumin (500 mg kg^‐1 day^‐1, oral gavage) for 14 days in two separate groups beginning at either 26 or 32 weeks of age. Body weight and composition were monitored throughout the study. Immune activity was assessed by spleen weight, circulating dsDNA autoantibodies, and B lymphocytes. Renal injury (albumin excretion, glomerulosclerosis, blood urea nitrogen (BUN)) was measured as a hemodynamic function (glomerular filtration rate (GFR), mean arterial pressure (MAP)) in conscious mice. Body weight and composition were maintained in curcumin‐treated SLE mice, but decreased in vehicle‐treated SLE mice. Curcumin‐treated SLE mice had lower spleen weight and renal injury (glomerulosclerosis) compared to vehicle‐treated SLE mice when treatment started at 26 weeks of age. When curcumin treatment started at 32 weeks of age, renal injury (glomerulosclerosis, BUN) was reduced in SLE mice compared to vehicle‐treated SLE mice. GFR was reduced, and MAP was increased in vehicle‐treated SLE mice compared to controls; however, these were not improved with curcumin. No significant changes were observed in curcumin‐treated control mice. These data suggest that curcumin modulates autoimmune activity and may lessen renal injury in female mice with SLE.

Temporal hemodynamic changes in a female mouse model of systemic lupus erythematosus

Systemic lupus erythematosus (SLE) is a chronic multisystem autoimmune disease characterized by circulating autoantibodies, prevalent hypertension, renal injury, and cardiovascular disease. Onset of the disease often occurs in young women of childbearing age. Although kidney involvement is common to patients with SLE, little is known about temporal changes in renal hemodynamic function and its relationship to the pathogenesis of hypertension during autoimmune diseases. We hypothesized that the loss of immunological tolerance and subsequent production of autoantibodies in SLE leads to impaired renal hemodynamic function that precedes the development hypertension. Female NZBWF1 (SLE) mice and female NZW/LacJ (control) mice were instrumented with carotid artery and jugular vein catheters to determine mean arterial pressure (MAP) and glomerular filtration rate, respectively, at ages of 15, 20, 24, 28, 31, and 34 wk. In addition, urinary albumin excretion, blood urea nitrogen, circulating autoantibodies, and glomerulosclerosis were assessed at each age. Levels of circulating autoantibodies are increased between 24 and 28 wk of age in NZBWF1 mice and were significantly greater than in control mice. Glomerular filtration rate was significantly increased at 28 wk of age in NZBWF1 mice followed by a sharp decline at 34 wk of age. NZBWF1 mice had an increase in MAP that occurred by 34 wk of age. These data show that changes in circulating autoantibodies, renal hemodynamic function, and glomerular injury occur in NZBWF1 mice before changes in MAP, suggesting an important mechanistic role for autoimmunity to directly impair renal hemodynamic function and promote the development of hypertension.

Treatment with a CD40 Antagonist Antibody Reverses Severe Proteinuria and Loss of Saliva Production and Restores Glomerular Morphology in Murine Systemic Lupus Erythematosus

CD40 is a costimulatory receptor on APCs that is critical for the induction and maintenance of humoral and cell-mediated immunity. Accordingly, CD40 and its ligand, CD40L, have long been considered targets for the treatment of autoimmune diseases. We developed a rat/mouse chimeric anti-mouse CD40 antagonist mAb, 201A3, and evaluated its ability to alleviate murine lupus. Treatment of NZB/W-F₁ mice with 201A3 after the onset of severe proteinuria rapidly reversed established severe proteinuria and nephritis and largely restored normal glomerular and tubular morphology. This coincided with a normalization of the expression of genes associated with proteinuria and injury by kidney parenchymal cells. Anti-CD40 treatment also prevented and reversed loss of saliva production and sialadenitis. These effects on kidney and salivary gland function were confirmed using mice of a second strain, MRL/Mp-lpr/lpr, and extended to alleviating joint inflammation. Immunologically, anti-CD40 treatment disrupted multiple processes that contribute to the pathogenesis of systemic lupus erythematosus (SLE), including autoreactive B cell activation, T effector cell function in target tissues, and type I IFN production. This ability to disrupt disease-critical immunological mechanisms, to reverse glomerular and tubular injury at the cellular and gene expression levels, and to confer exceptional therapeutic efficacy suggests that CD40 is a central disease pathway in murine SLE. Thus, a CD40 antagonist Ab could be an effective therapeutic in the treatment of SLE.

Topoisomerase 1B poisons: Over a half-century of drug leads, clinical candidates, and serendipitous discoveries

Topoisomerases are DNA processing enzymes that relieve supercoiling (torsional strain) in DNA, are necessary for normal cellular division, and act by nicking (and then religating) DNA strands. Type 1B topoisomerase (Top1) is overexpressed in certain tumors, and the enzyme has been extensively investigated as a target for cancer chemotherapy. Various chemical agents can act as "poisons" of the enzyme's religation step, leading to Top1-DNA lesions, DNA breakage, and eventual cellular death. In this review, agents that poison Top1 (and have thus been investigated for their anticancer properties) are surveyed, including natural products (such as camptothecins and indolocarbazoles), semisynthetic camptothecin and luotonin derivatives, and synthetic compounds (such as benzonaphthyridines, aromathecins, and indenoisoquinolines), as well as targeted therapies and conjugates. Top1 has also been investigated as a therapeutic target in certain viral and parasitic infections, as well as autoimmune, inflammatory, and neurological disorders, and a summary of literature describing alternative indications is also provided. This review should provide both a reference for the medicinal chemist and potentially offer clues to aid in the development of new Top1 poisons.

Suppression of lupus nephritis and skin lesions in MRL/lpr mice by administration of the topoisomerase I inhibitor irinotecan

BACKGROUND

Since the precise mechanism for the pathogenesis of systemic lupus erythematosus (SLE) is unknown, no targeted therapies in addition to immunosuppression are available so far. We recently demonstrated that administration of the topoisomerase I (topo I) inhibitor irinotecan at extremely low concentrations reversed established lupus nephritis in NZB/NZW mice. While profound immunosuppression was absent, we proposed changes in DNA relaxation and anti-double-stranded (ds)DNA antibody binding as the underlying mechanism. To exclude that these effects were restricted to NZB/NZW mice, irinotecan was used in a genetically different strain of lupus-prone mice.

METHODS

MRL/lpr mice were treated with high- and low-dose irinotecan beginning at 8 weeks of age. Treatment was repeated every fourth week. In vitro, DNA was relaxed by recombinant topo I, and altered anti-dsDNA antibody binding was measured by enzyme-linked immunosorbent assay.

RESULTS

Administration of both high- and low-dose irinotecan prevented proteinuria and prolonged survival in MRL/lpr mice. Moreover, both concentrations of irinotecan significantly improved histopathology of the skin at 18 weeks of age. While only high-dose irinotecan diminished the numbers of plasmablasts and double-negative T cells, no changes in IgG-secreting cells or anti-dsDNA IgG were observed. In vitro, relaxation of DNA by topo I increased the binding of anti-dsDNA IgG but not the binding of anti-dsDNA IgM derived from the plasma of MRL/lpr mice.

CONCLUSION

The beneficial effects of topo I inhibition in a second, genetically different strain of lupus-prone mice strongly implicate irinotecan as a new therapeutic option for human SLE.

The Topoisomerase I Inhibitor Irinotecan and the Tyrosyl-DNA Phosphodiesterase 1 Inhibitor Furamidine Synergistically Suppress Murine Lupus Nephritis

OBJECTIVE

The treatment of lupus nephritis is still an unmet medical need requiring new therapeutic approaches. Our group found recently that irinotecan, an inhibitor of topoisomerase I (topo I), reversed proteinuria and prolonged survival in mice with advanced lupus nephritis. While irinotecan is known to stabilize the complex of topo I and DNA, the enzyme tyrosyl-DNA phosphodiesterase 1 (TDP-1) functions in an opposing manner by releasing topo I from DNA. Therefore, we undertook this study to test whether the TDP-1 inhibitor furamidine has an additional effect on lupus nephritis when used in combination with irinotecan.

METHODS

NZB/NZW mice were treated with low-dose irinotecan and furamidine either alone or in combination beginning at age 26 weeks. DNA relaxation was visualized using gel electrophoresis. Binding of anti-double-stranded DNA (anti-dsDNA) antibodies to DNA modified by topo I, TDP-1, and the topo I inhibitor camptothecin was determined by enzyme-linked immunosorbent assay.

RESULTS

Compared to treatment with either agent alone, simultaneous treatment with low-dose irinotecan and furamidine significantly improved survival of NZB/NZW mice. Similar to what has been previously shown for irinotecan alone, the combination treatment did not change the levels of anti-dsDNA antibodies. In vitro, recombinant TDP-1 increased topo I-mediated DNA relaxation, resulting in enhanced binding of anti-dsDNA antibodies. In combination with topo I and camptothecin, TDP-1 reversed the inhibitory effects of camptothecin on DNA relaxation and anti-dsDNA binding.

CONCLUSION

Affecting DNA relaxation by the enzymes topo I and TDP-1 and their inhibitors may be a promising approach for the development of new targeted therapies for systemic lupus erythematosus.

Influence of natural killer cells and perforin‑mediated cytolysis on the development of chemically induced lung cancer in A/J mice

One alternative approach for the treatment of lung cancer might be the activation of the immune system using vaccination strategies. However, most of clinical vaccination trials for lung cancer did not reach their primary end points, suggesting that lung cancer is of low immunogenicity. To provide additional experimental information about this important issue, we investigated which type of immune cells contributes to the protection from lung cancer development. Therefore, A/J mice induced for lung adenomas/ adenocarcinomas by the tobacco-specific nitrosamine 4-(methylnitrosamino)-1-(3-pyridyl)-1-butanone (NNK) were depleted of CD4+ or CD8+ T cells, CD11b+ macrophages, Gr-1+ neutrophils and asialo GM1+ natural killer (NK) cells. Subsequent analysis of tumour growth showed an increase in tumour number only in mice depleted of NK cells. Further asking by which mechanism NK cells suppressed tumour development, we neutralized several death ligands of the tumour necrosis factor (TNF) family known to be involved in NK cell-mediated cytotoxicity. However neither depletion of TNF-α, TNF-related apoptosis-inducing ligand, TNF-like weak inducer of apoptosis or FasL alone nor in combination induced an augmentation of tumour burden. To show whether an alternative cell death pathway is involved, we next generated A/J mice deficient for perforin. After challenging with NNK, mice deficient for perforin showed an increase in tumour number and volume compared to wild-type A/J mice. In summary, our data suggest that NK cells and perforin-mediated cytolysis are critically involved in the protection from lung cancer giving promise for further immunotherapeutic strategies for this disease.

Effects of adjuvants for human use in systemic lupus erythematosus (SLE)-prone (New Zealand black/New Zealand white) F1 mice

The safety of four different adjuvants was assessed in lupus-prone New Zealand black/New Zealand white (BW)F1 mice. Four groups of mice were injected intraperitoneally with incomplete Freund's adjuvant (IFA), complete Freund's adjuvant (CFA), squalene (SQU) or aluminium hydroxide (ALU). An additional group received plain phosphate-buffered saline (PBS) (UNT group). Mice were primed at week 9 and boosted every other week up to week 15. Proteinuria became detectable at weeks 17 (IFA group), 24 (CFA group), 28 (SQU and ALU groups) and 32 (UNT group). Different mean values were obtained among the groups from weeks 17 to 21 [week 17: one-way analysis of variance (anova) P = 0·016; weeks 18 and 19: P = 0·048; weeks 20 and 21: P = 0·013] being higher in the IFA group than the others [Tukey's honestly significant difference (HSD) post-test P < 0·05]. No differences in anti-DNA antibody levels were observed among groups. Anti-RNP/Sm antibody developed at week 19 in only one CFA-treated mouse. Mean mouse weight at week 18 was lower in the ALU group than the IFA (Tukey's HSD post-test P = 0·04), CFA (P = 0·01) and SQU (P < 0·0001) groups, while the mean weight in the SQU group was higher than in the IFA (P = 0·009), CFA (P = 0·013) and UNT (P = 0·005) groups. The ALU group weight decreased by almost half between weeks 29 and 31, indicating some toxic effect of ALU in the late post-immunization period. Thus, SQU was the least toxic adjuvant as it did not (i) accelerate proteinuria onset compared to IFA; (ii) induce toxicity compared to ALU or (iii) elicit anti-RNP/Sm autoantibody, as occurred in the CFA group.

New approaches for the treatment of lupus nephritis in the 21st century: from the laboratory to the clinic

Systemic lupus erythematosus is a complex autoimmune disorder affecting multiple organ systems. Glomerulonephritis leading to severe proteinuria, chronic renal failure and end-stage renal disease remains one of the most severe complications of systemic lupus erythematosus and is associated with significant morbidity and mortality. Conventional lupus nephritis (LN) treatment based on cyclophosphamide, steroids and, recently, mycophenolatemofetil has improved the outcome of the disease over the last 50 years, although failure to achieve remission or treatment resistance has been reported in 18–57% of patients. Chronic complications such as long-term toxicity dampen their ability to maintain disease remission. There is a need to develop more specific pharmacological agents for patients to provide choices that are equally effective, less toxic and have fewer complications. During the last 10 years, experimental studies based on different pathogenesis pathways of LN have provided an enormous amount of knowledge and have offered the possibility to target the disease with selective approaches. In this article, we summarize the new experimental strategies that have recently been utilized to target LN, focusing on mechanisms of action.

The effect of targeted delivery of anti-TNF-α oligonucleotide into CD169+ macrophages on disease progression in lupus-prone MRL/lpr mice

Systemic blockade of TNF-α via monoclonal antibodies and soluble receptors has shown considerable effects against several typical autoimmune disorders, but remains unconvincing for the treatment of lupus. Based on our previous study, a CD169(+) macrophage-specific therapy using TNF-α antisense oligonucleotides (ASO) was tested for its efficacy in MRL/lpr lupus-prone mice. ASO-containing cationic agarose hydrogel were injected into mice subcutaneously. Tissue distribution and cellular localization of ASO were determined. The therapeutic effects and possible mechanism were further studied in MRL/lpr lupus-prone mice. The results showed that specifically accumulation of the anti-TNF-α ASO in CD169(+) macrophages could significantly reduce TNF-α expression in CD169(+) macrophages and inhibit lymphocytes over-proliferation, finally resulted in the relief of the lupus-like symptoms of the animals. The nucleic acid drug based on CD169(+) macrophage-specific TNF-α regulation represents a potential therapeutic approach that may be valuable for lupus therapy.

Structural modification of DNA--a therapeutic option in SLE?

Systemic lupus erythematosus (SLE) is an autoimmune disease that affects multiple organs, with glomerulonephritis representing a frequent and serious manifestation. SLE is characterized by the presence of various autoantibodies, including anti-DNA antibodies that occur in approximately 70% of patients with SLE and which contribute to disease pathogenesis. Consequently, immunosuppressive therapies are applied in the treatment of SLE to reduce autoantibody levels. However, increasing evidence suggests that DNA--especially double--stranded DNA-constitutes an important pathogenic factor that is able to activate inflammatory responses by itself in autoimmune diseases. Therefore, modifying the structure of DNA to reduce its pathogenicity might be a more targeted approach for the treatment of SLE than immunosuppression. This article presents information in support of this strategy, and discusses the potential methods of DNA structure manipulation--in light of data obtained from mouse models of SLE--including topoisomerase I inhibition, administration of DNase I, or modification of histones using heparin or histone deacetylase inhibitors.

Murine models of systemic lupus erythematosus

Systemic lupus erythematosus (SLE) is a multifactorial autoimmune disorder. The study of diverse mouse models of lupus has provided clues to the etiology of SLE. Spontaneous mouse models of lupus have led to identification of numerous susceptibility loci from which several candidate genes have emerged. Meanwhile, induced models of lupus have provided insight into the role of environmental factors in lupus pathogenesis as well as provided a better understanding of cellular mechanisms involved in the onset and progression of disease. The SLE-like phenotypes present in these models have also served to screen numerous potential SLE therapies. Due to the complex nature of SLE, it is necessary to understand the effect specific targeted therapies have on immune homeostasis. Furthermore, knowledge gained from mouse models will provide novel therapy targets for the treatment of SLE.

Treatment of proliferative lupus nephritis: a slowly changing landscape

Proliferative lupus nephritis is the most severe form of lupus nephritis. Outcomes of this disease are affected by ethnicity, clinical characteristics, irreversible damage on renal biopsy, initial response to treatment and future disease course (for example, the occurrence of renal flares). Initial intensive (induction) treatment of proliferative lupus nephritis is aimed at achieving remission, but optimal duration and intensity are not well defined. A combination of intravenous cyclophosphamide and corticosteroids have been shown to decrease the risk of end-stage renal disease, but are associated with substantial acute toxic effects (such as infections) and chronic toxic effects (such as ovarian failure). In white populations, low-dose cyclophosphamide is a reasonable alternative to high-dose cyclophosphamide as it is similarly effective and associated with less toxicity. Mycophenolate mofetil is as effective as high-dose intravenous cyclophosphamide in terms of inducing remission and similar in terms of safety. Although most patients respond to induction treatment, remission is often only achieved after patients are switched to maintenance treatment. As maintenance treatment, mycophenolate mofetil is superior to azathioprine and azathioprine is similarly effective to ciclosporin in terms of prevention or reducing the risk of relapse. Rituximab should be reserved for patients with refractory disease. Treatment of lupus nephritis should be individually tailored to patients, with more aggressive therapy reserved for patients at high risk of renal dysfunction and progression of renal disease.