Model Of Lupus Nephritis Research Articles

Cluster of differentiation-44 as a novel biomarker of lupus nephritis and its role in kidney inflammation and fibrosis.

CD44 is a transmembrane glycoprotein implicated in tissue inflammation and fibrosis. We investigated its role in kidney inflammation and fibrosis in a murine model of lupus nephritis (LN), and the clinico-pathological association of serum CD44 level in patients with biopsy-proven Class III/IV ± V LN. NZB/W F1 mice were treated with control IgG or anti-CD44 monoclonal antibody for 4 weeks and disease parameters assessed. Serum CD44 level in LN patients was determined by ELISA. Control groups included healthy subjects and patients with non-renal SLE or non-lupus renal disease. CD44 expression was absent in the normal kidney, but it was expressed in proximal and distal tubular epithelial cells and infiltrating cells in renal biopsies from patients with active proliferative LN. ScRNA-Seq datasets confirmed that CD44 was predominantly expressed in tubular cells and all immune cells identified in LN patients including tissue resident, inflammatory and phagocytic macrophages, Treg cells, effector and central memory CD4+ T cells, resident memory CD8+ T cells and naïve and activated B cells. Treatment of NZB/W F1 mice with anti-CD44 antibody preserved kidney histology and reduced proteinuria, tubulo-interstitial infiltration of CD3+, CD4+ and CD19+ immune cells, and mediators of kidney fibrosis compared to Control mice. Longitudinal studies showed that serum CD44 level increased prior to clinical renal flare by 4.5 months and the level decreased after treatment. ROC curve analysis showed that CD44 level distinguished patients with active LN from healthy subjects and patients with quiescent LN, active non-renal lupus, and non-lupus CKD (ROC AUC of 0.99, 0.96, 0.99 and 0.99 respectively). CD44 level correlated with leukocyte infiltration and interstitial inflammation scores in active LN kidney biopsies. Our findings suggest that CD44 plays a pathogenic role in renal parenchymal inflammation and fibrosis in active LN and monitoring CD44 may facilitate early diagnosis of flare.

Dimethyloxallyl Glycine Preconditioning Promotes the Anti-inflammatory and Anti-fibrotic Effects of Human Umbilical Cord Mesenchymal Stem Cells on Kidney Damage in Systemic Lupus Erythematosus Related to TGF-β/Smad Signaling Pathway.

Systemic lupus erythematosus (SLE) is a chronic inflammatory autoimmune disease lacking effective treatments without adverse effects. Dimethyloxallyl glycine (DMOG) enhanced mesenchymal stem cells (MSC) capabilities, but it remains unclear how DMOG-pretreatment of MSCs augments their SLE treatment. Here, we explore the therapeutic potential of DMOG-pretreated human umbilical cord MSCs (hUC-MSCs) in a mouse lupus nephritis (LN) model. In vitro experiments showed that DMOG could alleviate the mRNA levels of tumor necrosis factor (TNF)-α, interferon (IFN)-γ, and interleukin (IL)-6 and increase the mRNA level of IL-13 in lipopolysaccharide (LPS)-induced inflammation in hUC-MSCs. DMOG enhanced the migratory and invasive abilities of the hUC-MSCs. In vivo animal studies revealed that DMOG-pretreated hUC-MSCs exhibited more pronounced inhibition of lymphadenectasis and reduced kidney weight and urinary protein content than MSCs alone. DMOG-pretreated hUC-MSCs improved renal morphological structure and alleviated inflammatory cell infiltration and renal fibrosis, evidenced by the reduced mRNA levels of fibrosis markers, including fibronectin (Fn), collagen alpha-1 chain (Colα1), collagen alpha-3 chain (Colα3), and TNF-α, IFN-γ, and IL-6 cytokines. Further investigation revealed that DMOG-pretreated hUC-MSCs down-regulated the expressions of transforming growth factor (Tgf)-β1 and its downstream effectors Smad2 and Smad3, recognized as central mediators in renal fibrosis (P < 0.05). The findings suggest that DMOG-pretreated hUC-MSCs can augment the therapeutic efficacy of hUC-MSCs in LN by enhancing their anti-inflammatory and antifibrotic effects, and the TGF-β/Smad signaling pathway may be involved in this process.

Multiscale topology classifies cells in subcellular spatial transcriptomics

Spatial transcriptomics measures in situ gene expression at millions of locations within a tissue1, hitherto with some trade-off between transcriptome depth, spatial resolution and sample size2. Although integration of image-based segmentation has enabled impactful work in this context, it is limited by imaging quality and tissue heterogeneity. By contrast, recent array-based technologies offer the ability to measure the entire transcriptome at subcellular resolution across large samples3–6. Presently, there exist no approaches for cell type identification that directly leverage this information to annotate individual cells. Here we propose a multiscale approach to automatically classify cell types at this subcellular level, using both transcriptomic information and spatial context. We showcase this on both targeted and whole-transcriptome spatial platforms, improving cell classification and morphology for human kidney tissue and pinpointing individual sparsely distributed renal mouse immune cells without reliance on image data. By integrating these predictions into a topological pipeline based on multiparameter persistent homology7–9, we identify cell spatial relationships characteristic of a mouse model of lupus nephritis, which we validate experimentally by immunofluorescence. The proposed framework readily generalizes to new platforms, providing a comprehensive pipeline bridging different levels of biological organization from genes through to tissues.

Imaging kidney inflammation using an oxidatively activated MRI probe

Imaging tools for kidney inflammation could improve care for patients suffering inflammatory kidney diseases by lessening reliance on percutaneous biopsy or biochemical tests alone. During kidney inflammation, infiltration of myeloid immune cells generates a kidney microenvironment that is oxidizing relative to normal kidney. Here, we evaluated whether magnetic resonance imaging (MRI) using the redox-active iron (Fe) complex Fe-PyC3A as an oxidatively activated probe could serve as a marker of kidney inflammation using mouse models of unilateral ischemia-reperfusion injury (IRI) and lupus nephritis (MRL-lpr mice). We imaged unilateral IRI in gp91phox knockout mice, which are deficient in the nicotinamide oxidase II (NOX2) enzyme required for myeloid oxidative burst, as loss of function control, and imaged MRL/MpJ mice as non-kidney involved lupus control. Gadoterate meglumine was used as a non-oxidatively activated control MRI probe. Fe-PyC3A safety was preliminarily examined following a single acute dose. Fe-PyC3A generated significantly greater MRI signal enhancement in the IRI kidney compared to the contralateral kidney in wild-type mice, but the effect was not observed in the NOX2-deficient control. Fe-PyC3A also generated significantly greater kidney enhancement in MRL-lpr mice compared to MRL/MpJ control. Gadoterate meglumine did not differentially enhance the IRI kidney over the contralateral kidney and did not differentially enhance the kidneys of MRL-lpr over MRL/MpJ mice. Fe-PyC3A was well tolerated at the highest dose evaluated, which was a 40-fold greater than required for imaging. Thus, our data indicate that MRI using Fe-PyC3A is specific to an oxidizing kidney environment shaped by activity of myeloid immune cells and support further evaluation of Fe-PyC3A for imaging kidney inflammation.

PIK3CA inhibition in models of proliferative glomerulonephritis and lupus nephritis.

Proliferative glomerulonephritis is a severe condition that often leads to kidney failure. There is a significant lack of effective treatment for these disorders. Here, following the identification of a somatic PIK3CA gain-of-function mutation in podocytes of a patient, we demonstrate using multiple genetically engineered mouse models, single-cell RNA sequencing, and spatial transcriptomics the crucial role played by this pathway for proliferative glomerulonephritis development by promoting podocyte proliferation, dedifferentiation, and inflammation. Additionally, we show that alpelisib, a PI3Kα inhibitor, improves glomerular lesions and kidney function in different mouse models of proliferative glomerulonephritis and lupus nephritis by targeting podocytes. Surprisingly, we determined that pharmacological inhibition of PI3Kα affects B and T lymphocyte populations in lupus nephritis mouse models, with a decrease in the production of proinflammatory cytokines, autoantibodies, and glomerular complement deposition, which are all characteristic features of PI3Kδ inhibition, the primary PI3K isoform expressed in lymphocytes. Importantly, PI3Kα inhibition does not impact lymphocyte function under normal conditions. These findings were then confirmed in human lymphocytes isolated from patients with active lupus nephritis. In conclusion, we demonstrate the major role played by PI3Kα in proliferative glomerulonephritis and show that in this condition, alpelisib acts on both podocytes and the immune system.

#525 SGLT2 inhibition in non-diabetic CKD: results in experimental lupus nephritis

Abstract Background and Aims Sodium glucose cotransporter type 2 inhibitors (SGLT2i) potently attenuate cardiovascular morbidity and progression of CKD in patients with type 2 diabetes. It has been proposed that SGLT2 inhibition may also elicit renoprotective effects in non-diabetic CKD. The aim of this work is to evaluate whether the treatment with an SGLT2i improves kidney disease progression in a mouse model of lupus nephritis (LN). Method We performed a single center randomized controlled preclinical trial using female MRLlpr/lpr mice. The animals were randomly assigned to (1) vehicle or (2) empagliflozin (EMP, 10 mg/kg/day) treatment once signs of active systemic lupus erythematosus (SLE) appeared: proteinuria &amp;gt;100 mg/dL (++ in reactive strips) or lymphadenopathy in minimum 2 bilateral sites with proteinuria &amp;gt;30 mg/dL (+ in reactive strips). We included 13 mice per group that were treated during 4 weeks. Empagliflozin was given as an admix into standard chow diet. Reduction of urinary albumin to creatine ratio (UACR) was considered the primary endpoint whereas glomerular filtration rate (GFR), renal histology (LN activity/chronicity index, glomerulosclerosis, interstitial fibrosis) and SLE markers (total serum IgG, anti-dsDNA IgG, glomerular IgG deposits, lymph node weight, spleen weight) were considered secondary endpoints. Results After 4 weeks of treatment, no significant differences in fasting blood glucose levels were found between the experimental groups. As expected, empagliflozin administration notably inhibited SGLT2 in the tubular cells demonstrated by a significant increase of urinary glucose (p &amp;lt; 0.0001). This is consistent with the increased water intake observed in MRLlpr/lpr mice treated with empagliflozin (p &amp;lt; 0.0001). At the end of the experiment, vehicle treated MRLlpr/lpr mice showed a significant increase in UACR (p = 0.0012) consistent with LN progression that was not attenuated by empagliflozin. In line, empagliflozin did not modify GFR and LN activity/chronicity indexes, glomerulosclerosis or interstitial fibrosis in kidney. Finally, regarding SLE markers, 4-weeks empagliflozin treatment was not able to decrease total serum IgG, anti-dsDNA IgG, glomerular IgG deposits or lymph node weight. Only spleen weight was significantly decreased in empagliflozin treated MRLlpr/lpr mice (p = 0.003). Conclusion In our experimental setting, empagliflozin treatment reduced spleen weight suggesting a protective role in SLE in MRLlpr/lpr mice. However, empagliflozin did not modify LN progression in MRLlpr/lpr mice probably because the acute LN phase. It is expected that the positive effect in terms of reducing proteinuria will be observed in patients with LN and residual proteinuria

Deep learning model to predict lupus nephritis renal flare based on dynamic multivariable time-series data

ObjectivesTo develop an interpretable deep learning model of lupus nephritis (LN) relapse prediction based on dynamic multivariable time-series data.DesignA single-centre, retrospective cohort study in China.SettingA Chinese central tertiary hospital.ParticipantsThe cohort...

Smith-specific regulatory T cells halt the progression of lupus nephritis

Antigen-specific regulatory T cells (Tregs) suppress pathogenic autoreactivity and are potential therapeutic candidates for autoimmune diseases such as systemic lupus erythematosus (SLE). Lupus nephritis is associated with autoreactivity to the Smith (Sm) autoantigen and the human leucocyte antigen (HLA)-DR15 haplotype; hence, we investigated the potential of Sm-specific Tregs (Sm-Tregs) to suppress disease. Here we identify a HLA-DR15 restricted immunodominant Sm T cell epitope using biophysical affinity binding assays, then identify high-affinity Sm-specific T cell receptors (TCRs) using high-throughput single-cell sequencing. Using lentiviral vectors, we transduce our lead Sm-specific TCR into Tregs derived from patients with SLE who are anti-Sm and HLA-DR15 positive. Compared with polyclonal mock-transduced Tregs, Sm-Tregs potently suppress Sm-specific pro-inflammatory responses in vitro and suppress disease progression in a humanized mouse model of lupus nephritis. These results show that Sm-Tregs are a promising therapy for SLE.

Hyperbaric oxygen as an immunosuppressant in mouse model of lupus nephritis

Lupus nephritis (LN) is the main cause of morbidity and death due to the most severe complications of the kidney organ in Systemic Lupus Erythematosus (SLE). Immunosuppressive drugs are needed to control this disease, but currently available immunosuppressive drugs do not provide optimal results. This research used 21 Mus Musculus BALB/c mice, female, body weight 25 – 30 grams, 8-12 weeks old, healthy and active, divided into 3 groups. The group of normal mice (G1) was the negative control group, the group of lupus nephritis mice without Hyperbaric Oxygen (HBO) therapy (G2) was the positive control group and the group of lupus nephritis mice with HBO therapy (G3) was the treatment group. The results showed a significant reduction in anti-dsDNA Ab levels p = 0.002 (p&lt;0.05) and proteinuria levels p = 0.005 (p&lt;0.05) in the group given HBO (G3) compared to the group not given HBO (G2). Repair of kidney tissue damage was characterized by a decrease in inflammatory cells, a decrease in tubular constriction and a decrease in immune complex deposits in the group given HBO (G3) compared to the group not given HBO (G2). So HBO can reduce anti-dsDNA Ab levels and proteinuria, and repair damaged kidney tissue. HBO as an immunosuppressive can be used as additional therapy in lupus nephritis.

Purification and analysis of kidney-infiltrating leukocytes in a mouse model of lupus nephritis.

Renal injury often occurs as a complication in autoimmune diseases such as systemic lupus erythematosus (SLE). It is estimated that a minimum of 20% SLE patients develop lupus nephritis, a condition that can be fatal when the pathology progresses to end-stage renal disease. Studies in animal models showed that incidence of immune cell infiltrates in the kidney was linked to pathological injury and correlated with severe lupus nephritis. Thus, preventing immune cell infiltration into the kidney is a potential approach to impede the progression to an end-stage disease. A requirement to investigate the role of kidney-infiltrating leukocytes is the development of reproducible and efficient protocols for purification and characterization of immune cells in kidney samples. This chapter describes a detailed methodology that discriminates tissue-resident leukocytes from blood-circulating cells that are found in kidney. Our protocol was designed to maximize cell viability and to reduce variability among samples, with a combination of intravascular staining and magnetic bead separation for leukocyte enrichment. Experiments included as example were performed with FcγRIIb[KO] mice, a well-characterized murine model of SLE. We identified T cells and macrophages as the primary leukocyte subsets infiltrating into the kidney during severe nephritis, and we extensively characterized them phenotypically by flow cytometry.

Effects of Acupuncture Therapy at the Mingmen (GV4) and Zusanli (ST36) Points on the Expression of Transforming Growth Factor Beta 1 in Mice with Lupus Nephritis Model

Introduction: Systemic Lupus Erythematosus (SLE) is a chronic autoimmune inflammation involving various factors and autoantibodies targeting cell components, resulting in epigenetic changes. Lupus nephritis is one of the clinical manifestations of SLE. Nowadays, it is known that acupuncture could inhibit disease development, including chronic nephritis, chronic diarrhea, lumbago adnexitis, impotence, enuresis in children, myelitis, and endometritis. Thus, this study aimed to examine the effect of improving Mingmen (GV4) and Zusanli (ST36) point acupuncture therapy on the expression of Transforming Growth Factor Beta 1 (TGFβ1) in lupus nephritis model mice. Method: It was a laboratory experiment on mice (Mus musculus) lupus nephritis model with a post-test only with a control group design. The research samples were divided into four groups, with seven mice in each group, consisting of a control group (KN), a negative control group given pristane (K), treatment group 1 (P1); given pristane and methylprednisolone, and a treatment group 2 (P2); given pristane and acupuncture at the Mingmen (GV4) and Zusanli (ST36) points. This acupuncture needle insertion was carried out thrice a week for 12 insertions during the intervention. The bivariate analysis was done using Kruskal Wallis. Results: There were 28 samples examined in this study. we found that the TGFβ1 expression was high in group P2 (72.86±11.13), after that followed by group P1 (65.71±25.73), N (60.71±25.24), and K (5.88±5.35). According to the bivariate analysis, it showed a significant difference in TGF-β (p= 0.010). Conclusion: Mingmen (GV4) and Zusanli (ST36) point acupuncture therapy improves TGFβ1 expression. Acupuncture therapy triggers inhibition of TGF-β1 expression in lupus nephritis model mice.

Proximal Tubular Sirt6 Has a Protective Role in the Murine Lupus Nephritis Model by Regulating Tubulointerstitial Inflammation

Proximal Tubular Sirt6 Has a Protective Role in the Murine Lupus Nephritis Model by Regulating Tubulointerstitial Inflammation

TLR9 regulates the autophagy-lysosome pathway to promote dendritic cell maturation and activation by activating the TRAF6-cGAS-STING pathway.

Dysregulated maturation and activation of dendritic cells (DCs) play a significant role in the progression of systemic lupus erythematosus (SLE). The autophagy-lysosome pathway has been identified as a potential mechanism to inhibit DC activation and maturation, but its precise workings remain unclear. We investigated the role and regulatory mechanism of TLR9 in modulating the autophagy-lysosome pathway and DCs activation. The mRNA and protein expressions were assessed using qRT-PCR and/or western blot. NZBW/F1 mice was used to construct a lupus nephritis (LN) model in vivo. Cell apoptosis was analyzed by TUNEL staining. Flow cytometry was adopted to analyze DCs surface markers. Lyso-tracker red staining was employed to analyze lysosome acidification. Levels of anti-dsDNA, cytokines, C3, C4, urine protein and urine creatinine were examined by ELISA. The results showed that TLR9 was markedly increased in SLE patients, and its expression was positively correlated with SLEDAI scores and dsDNA level. Conversely, TLR9 expression showed a negative correlation with C3 and C4 levels. Loss-of functionexperiments demonstrated that TLR9 depletion exerted a substantial inhibition of renal injury, inflammation, and DCs numbers. Additionally, upregulation of TLR9 promoted DCs maturation and activation through activation of autophagy and lysosome acidification. Further investigation revealed that TLR9 targeted TRAF6 to activate the cGAS-STING pathway. Rescue experiments revealed that inactivation of the cGAS/STING signaling pathway could reverse the promoting effects of TLR9 upregulation on DCs maturation, activation, and autophagy-lysosome pathway. Overall, our findings suggested that TLR9 activated the autophagy-lysosome pathway to promote DCs maturation and activation by activating TRAF6-cGAS-STING pathway, thereby promoting SLE progression.

Lactobacillus plantarum CQPC02 intervenes in mouse lupus nephritis by regulating the NF-κB signaling pathway.

A strain of Lactobacillus plantarum CQPC02 (LP-CQPC02) isolated from naturally fermented kimchi was utilized in this investigation. In order to construct an animal model of lupus nephritis, pristane was used. We then used a kit to identify markers in mouse blood and tissues and a quantitative polymerase chain reaction (qPCR) to measure the expression of genes associated to nuclear factor kappa-B (NF-κB) in mouse kidney tissue. According to the results of the experiments, oral administration of LP-CQPC02 LP-CQPC02 may lessen the lupus nephritis-related rise in urine protein as well as the cytokine levels that were rising in the serum and renal tissues, including IL-6, IL-12, tumor necrosis factor alpha, and interferon. Additionally, in mice with nephritis, LP-CQPC02 can lower serum creatinine (SCr), blood urea nitrogen (BUN), total cholesterol (TC), triglyceride (TG), and raise total protein (TP) and albumin (ALB) levels. In mice with nephritis, LP-CQPC02 can also reduce the positive rate of double-stranded deoxyribonucleic acid (dsDNA). Pathological sections were examined, and it was shown that LP-CQPC02 can lessen tissue damage such incomplete glomerular morphology and inflammatory infiltration brought on by nephritis. In the kidneys of mice with lupus nephritis, LP-CQPC02 can upregulate the expression of inhibitor of NF-κB (IκB-α), downregulate the expression of NF-κB, transforming growth factor-β1 (TGF-β1), vascular endothelial growth factor (VEGF), intercellular cell adhesion molecule-1 (ICAM-1), and vascular cell adhesion molecule-1 (VCAM-1). Lactobacillus plantarum CQPC02 has been confirmed to have an intervention effect on nephritis in mice and has the potential as a probiotic.

Cardiovascular changes in the NZB/W F1 mouse model of lupus nephritis.

Patients with systemic lupus erythematosus (SLE), an autoimmune disease, have a higher risk of cardiovascular (CV) disease and death. In addition, up to 40%-50% of SLE patients develop lupus nephritis (LN) and chronic kidney disease, which is an additional CV risk factor. Thus, the individual contributions of LN and other SLE-specific factors to CV events are unclear. In this study, we investigated the effect of LN on the development of CV changes using the female NZBxNZW F1 (NZB/W) mouse model of lupus-like disease, with female NZW mice as controls. Standard serologic, morphologic, immunohistologic, and molecular analyses were performed. In a separate group of NZB/W mice, systolic blood pressure (BP) was measured during the course of the disease using tail plethysmography. Our data show marked CV changes in NZB/W mice, i.e., increased heart weight, hypertrophy of the left ventricle (LV) and septum, and increased wall thickness of the intramyocardial arteries and the aorta, which correlated with the progression of renal damage, but not with the age of the mice. In addition, systolic BP was increased in NZB/W mice only when kidney damage progressed and proteinuria was present. Pathway analysis based on gene expression data revealed a significant upregulation of the response to interferon beta in NZB/W mice with moderate kidney injury compared with NZB mice. Furthermore, IFI202b and IL-6 mRNA expression is correlated with CV changes. Multiple linear regression analysis demonstrated serum urea as a surrogate marker of kidney function and IFI202b expression as an independent predictor for LV wall thickness. In addition, deposition of complement factors CFD and C3c in hearts from NZB/W mice was seen, which correlated with the severity of kidney disease. Thus, we postulate that the pathogenesis of CV disease in SLE is affected by renal impairment, i.e., LN, but it can also be partly influenced by lupus-specific cardiac expression of pro-inflammatory factors and complement deposition.

Analysis of risk factors and development of a nomogram prediction model for lupus nephritis in systemic lupus erythematosus patients

Background This study aimed to explore risk factors for lupus nephritis (LN) in systemic lupus erythematosus (SLE) patients and establish a Nomogram prediction model based on LASSO-logistic regression. Methods The clinical and laboratory data of SLE patients in Meishan People’s Hospital from July 2012 to December 2021 were analyzed retrospectively. All SLE patients were divided into two groups with or without LN. Risk factors were screened based on LASSO-logistic regression analysis, and a Nomogram prediction model was established. The receiver operating characteristic curve, calibration curves, and decision curve analysis were adopted to evaluate the performance of the Nomogram model. Results A total of 555 SLE patients were enrolled, including 303 SLE patients with LN and 252 SLE patients without LN. LASSO regression and multivariate logistic regression analyses showed that ESR, mucosal ulcer, proteinuria, and hematuria were independent risk factors for LN in SLE patients. The four clinical features were incorporated into the Nomogram prediction model. Results showed that calibration curve was basically close to the diagonal dotted line with slope 1 (ideal prediction case), which proved that the prediction ability of the model was acceptable. In addition, the decision curve analysis showed that the Nomogram prediction model could bring net clinical benefits to patients when the threshold probability was 0.12–0.54. Conclusion Four clinical indicators of ESR, mucosal ulcer, proteinuria, and hematuria were independent risk factors for LN in SLE patients. The predictive power of the Nomogram model based on LASSO-logistic regression was acceptable and could be used to guide clinical work.

#2598 KLOTHO DEFICIENCY INDUCES REGULATORY T CELLS IN MURINE LUPUS NEPHRITIS

Abstract Background and Aims Recent studies demonstrate that klotho deficiency participate in various chronic kidney disease. However, it has not been fully assessed the influence of klotho in autoimmune kidney diseases. On the one hand, klotho is known to binds transforming growth factor β (TGFβ) receptor to antagonize its pathophysiological actions including renal fibrosis. On the other hand, TGFβ is required to generate and maintain regulatory T cells with inducing FOXP3, an important cell population for immunological tolerance. Method NZBWF1 mice were used as a model of lupus nephritis. NZBWF1 mice were housed separately in metabolic cage, and divided into two groups (n=10 for each): one group was treated with daily subcutaneous injection of klotho protein (20 µg/kg/day), and the other received vehicle alone. Systolic blood pressure was measured by tail-cuff method. Glomerular filtration rate was assessed using FITC-inulin. Four weeks later, the animals were killed to harvest the spleen and kidneys for analyses. Results Klotho supplementation suppressed blood pressure, 8-epi-prostaglandin F2a excretion and renal angiotensin II levels (p&amp;lt;0.05 for all) without changes in albuminuria and glomerular filtration rate in NZBWF1 mice. Exogenous klotho protein supplementation increased serum klotho levels, urine klotho excretion, and endogenous renal expression of klotho in NZBWF1 mice (p&amp;lt;0.05 for all). Surprisingly, anti-double strand DNA antibody was slightly elevated in klotho-treated NZBWF1 mice (p&amp;lt;0.05). Glomerular pathology and interstitial cell infiltration were similar between 2 groups. The spleen tended to be greater in klotho-treated group, but statistical significance was not attained. In consistent, CD8+FOXP3+ T cells were unaltered between 2 groups. However, klotho supplementation reduced CD4+FOXP3+ T cells in spleen of NZBWF1 mice (p&amp;lt;0.05). Conclusion The present data indicated that klotho protein supplementation suppressed renal renin-angiotensin system, ameliorating blood pressure and oxidative stress. Our results suggest that klotho supplementation worsened auto-antibody, possibly by inhibiting TGFβ with resultant deterioration in regulatory T cells. The present findings implicate that although klotho may not suite for the management of autoimmune kidney diseases, such as lupus and ANCA-related nephritis, klotho supplementation for dialysis patients could mitigate against the defect in cellular immunity and susceptibility to infections including tuberculosis and COVID-19.

#3261 SAR131675, A SELECTIVE VEGFR3 INHIBITOR, AMELIORATES RENAL INFLAMMATION AND LYMPHANGIOGENESIS IN THE MURINE LUPUS NEPHRITIS MODEL

Abstract Background and Aims Systemic lupus erythematosus (SLE) is a chronic autoimmune disease characterized by immune-complex deposits and inflammatory cell infiltrations in multiple organs, and approximately half of lupus patients have nephritis. Lymphangiogenesis is the proliferation of pre-existing lymphatic vessels (LVs), which regulate tissue fluid homeostasis and immune cell trafficking, responding to the tissue environment. In this study, we evaluated the therapeutic effect of SAR131672, a selective VEGFR3 inhibitor, on the murine lupus nephritis model by regulating inflammation and lymphangiogenesis. Method First, we reviewed medical records for the biopsy-proven lupus nephritis and performed an immunohistochemistry study for D2-40. For animal experiments, seven to eight-week-old male BALB/c mice were used. The back area's skin was shaved and treated topically three times per week, with 100 μg of resiquimod in 100 μl of acetone for eight weeks and concomitantly treatment of VEGFR3 inhibitor, SAR 131672 by oral gavage. We evaluated renal histology and immunofluorescent study for inflammatory cells and lymphatic vessels. We also evaluated inflammatory cytokines and chemokines, lymphangiogenic factors by qRT-PCR. Results In a human study, we found that the higher lupus activity index, the more D2-40(+) lymphatic vessels are expressed in the tubulointerstitial areas. In an animal study, eight weeks of topical treatment of resiquimod to Balb/c mice induces lupus-like symptoms such as weight loss, splenomegaly, and glomerular immune complexes deposits such as IgG, IgM, and C3 in immunofluorescent staining. Histologically, glomerular mesangial cell proliferation and increased inflammatory cells in tubulointerstitial areas were noted in the H&amp;E stain. Inhibition of VEGFR3 by oral SAR131672 treatment decreases glomerular and tubulointerstitial inflammation and decreases LYVE-1(+) lymphatic vessels. The pro-inflammatory cytokines and chemokines such as ICAM-1, VCAM-1, MCP-1, CCL19, CCL21, CCR7, CXCL13, and BAFF mRNA levels were increased compared with the vehicle-treated group. Treatment SAR131672 decreases pro-inflammatory cytokines and chemokine. Conclusion Inhibition of VEGFR3 by SAR131672 decreases the resiquimod-induced lupus nephritis model by regulating inflammation and lymphangiogenesis.

Identification of T cell Autoantigens in a mouse model of Lupus Nephritis

Abstract Lupus nephritis (LN) is the most common severe organ manifestation of Systemic lupus erythematosus (SLE). Autoreactive CD4+ T cells play a key role in SLE, but the mechanism of loss of self-tolerance and antigen specificity of CD4+ T cells is unclear. CD4+ αβ T cells use their T cell receptor (TCR) to recognize 12–20 residue-long epitopes presented on class II MHC molecules. Identifying CD4+ T cell epitopes has been challenging due to lack of efficient and easy-to-implement methods for epitope discovery. We developed a robust T cell antigen discovery technology that uses chimeric receptors called SABR-II (Signaling and Antigen-presenting Bifunctional Receptors) to express large peptide antigen libraries in the context of MHC molecules. Using SABR-IIs, we sought to identify the autoantigens recognized by kidney-infiltrating CD4+ T cells in a mouse mode of LN – MRL/lpr mice. We used a high-throughput single cell TCR cloning to clone and express 93 TCRs from CD4+ T cells sorted from kidneys of 26-week-old MRL/lpr mice. For antigen discovery, we constructed SABR-IIs with I-Ek and I-Ak (class II MHC allele of MRL/lpr mice) and confirmed their functionality. We built libraries of ~25,000 epitopes derived from nuclear proteins and validated them using a known antigen-specific TCR. We have identified novel putative autoantigens, which will be validated in vitro. This study will lead to identification of novel self-antigens, providing the groundwork for understanding the biology of LN and for development of preventative and therapeutic approaches in SLE.

The Role of Glutathione Peroxidase 4 in Regulating Glomerular Permeability in a Mouse Model of Lupus Nephritis

Background/hypothesis of the study: Systemic lupus erythematosus (SLE) is a systemic autoimmune disease that often results in kidney damage (lupus nephritis). Glutathione peroxidase 4 (GPx4) is a key defensive player in clearing reactive oxygen species and preventing cell death using glutathione. Reductions of neutrophil GPx4 activity has recently been implicated in autoimmunity in SLE, and reduced renal expression of GPx4 was previously reported in a mouse model of SLE. Whether loss of GPx4 activity has a direct role in glomerular injury in SLE is currently unknown. Therefore, the present study aimed to investigate the role of GPx4 in regulating glomerular permeability and whether deficits in GPx4 may contribute to albuminuria in lupus nephritis. Methods and Results: Experiments utilized female (New Zealand Black x New Zealand White) F1 (NZBWF1) mice, a well-established mouse model of lupus nephritis that has a female sex bias, similar to patients. In our hands, these mice typically develop albuminuria around 34 weeks of age. Glomeruli were isolated on ice by graded sieving and underwent functional and biochemical analysis. Glomerular GPx4 expression was compared between age- and sex-matched albuminuric NZBWF1 mice (albuminuria status determined by dipstick) and healthy control New Zealand White (NZW) mice by western blot. Protein expression of GPx4 in glomeruli isolated from albuminuric 34-week-old female NZBWF1 mice was reduced to approximately 30% of the level found in NZW mice (P&lt;0.01; n=4 mice each group). For functional analysis, glomeruli were suspended in a 5% albumin solution, and the change in volume in response to a decrease in external oncotic pressure caused by switching to a 1% albumin solution was used to determine the albumin reflection coefficient and calculate relative glomerular permeability to albumin (Palb). Experiments measured (i) Palb of glomeruli from healthy young 8-week-old NZBWF1 compared to 34-week-old albuminuric NZBWF1, and (ii) Palb of glomeruli from 8-week-old NZBWF1 mice following ex vivo treatment of glomeruli with the GPx4 inhibitor RSL3 (3μM) for 30 minutes compared to untreated glomeruli from the same mice. At least 5-8 glomeruli/mouse/treatment or age were analyzed, and the data from each mouse was averaged. As expected, 34-week-old albuminuric NZBWF1 mice showed significantly increased Palb compared with 8-week-old mice (P&lt;0.001; n=5 mice per group). Glomeruli isolated from 8-week-old NZBWF1 mice showed increased Palb after 30 min incubation with 3μM RSL3 when compared to non-treated glomeruli (P&lt;0.001; n=4 mice per group). Conclusion: Our data suggest that the development of albuminuria in NZBWF1 mice is associated with a reduction in glomerular expression of GPx4, and impairment of GPx4 activity can promote increased Palb. A loss of GPx4 activity may contribute to glomerular filtration barrier dysfunction and albuminuria in SLE. This work was supported by the National Institutes of Health (grant number 1R01DK119337-01A1) This is the full abstract presented at the American Physiology Summit 2023 meeting and is only available in HTML format. There are no additional versions or additional content available for this abstract. Physiology was not involved in the peer review process.