Treatment of glomerulonephritis: will we ever have options other than steroids and cytotoxics?

Effect of Everolimus versus Bone Marrow-Derived Stem Cells on Glomerular Injury in a Rat Model of Glomerulonephritis: A Preventive, Predictive and Personalized Implication

Glomerular endothelial injury and effectiveness of glomerular endothelial repair play a crucial role in the progression of glomerulonephritis. Although the potent immune suppressive everolimus is increasingly used in renal transplant patients, adverse effects of its chronic use have been reported clinically in human glomerulonephritis and experimental renal disease. Recent studies suggest that progenitor stem cells could enhance glomerular endothelial repair with minimal adverse effects. Increasing evidence supports the notion that stem cell therapy and regenerative medicine can be effectively used in pathological conditions within the predictive, preventive and personalized medicine (PPPM) paradigm. In this study, using an experimental model of glomerulonephritis, we tested whether bone marrow-derived stem cells (BMDSCs) could provide better effect over everolimus in attenuating glomerular injury and improving the repair process in a rat model of glomerulonephritis. Anti-Thy1 glomerulonephritis was induced in male Sprague Dawley rats by injection of an antibody against Thy1, which is mainly expressed on glomerular mesangial cells. Additional groups of rats were treated with the immunosuppressant everolimus daily after the injection of anti-Thy1 or injected with single bolus dose of BMDSCs after one week of injection of anti-Thy1 (n = 6-8). Nine days after injection of anti-Thy1, glomerular albumin permeability and albuminuria were significantly increased when compared to control group (p < 0.05). Compared to BMDSCs, everolimus was significantly effective in attenuating glomerular injury, nephrinuria and podocalyxin excretion levels as well as in reducing inflammatory responses and apoptosis. Our findings suggest that bolus injection of BMDSCs fails to improve glomerular injury whereas everolimus slows the progression of glomerular injury in Anti-Thy-1 induced glomerulonephritis. Thus, everolimus could be used at the early stage of glomerulonephritis, suggesting potential implications of PPPM in the treatment of progressive renal injury.

Blockade of tumor necrosis factor superfamily members CD30 and OX40 abrogates disease activity in murine immune-mediated glomerulonephritis

Co-stimulation is a prerequisite for pathogenic activity in T cell-mediated diseases and has been demonstrated to achieve tolerance in organ-specific autoimmunity as a therapeutic target. Here, we evaluated the involvement of the tumor necrosis factor family members CD30 and OX40 in immune-complex mediated kidney disease. In vitro stimulation and proliferation studies were performed with CD4⁺ cells from wild type and CD30/OX40 double knock-out (CD30OX40^-/-) mice. In vivo studies were performed by induction of nephrotoxic serum nephritis in wild type, CD30OX40^{- /-} , CD30^-/-, OX40^-/-, reconstituted Rag1^-/- and C57Bl/6J mice treated with αCD30L αOX40L antibodies. CD30, OX40 and their ligands were upregulated on various leukocytes in nephrotoxic serum nephritis. CD30OX40^-/- mice, but not CD30^-/- or OX40^-/- mice were protected from nephrotoxic serum nephritis. Similar protection was found in Rag1^-/- mice injected with CD4⁺ T cells from CD30OX40^-/- mice compared to Rag1^-/- mice injected with CD4⁺ T cells from wild type mice. Furthermore, CD4⁺ T cells deficient in CD30OX40^-/- displayed decreased expression of CCR6 in vivo. CD30OX40^-/- cells were fully capable of differentiating into disease mediating T helper cell subsets, but showed significantly decreased levels of proliferation in vivo and in vitro compared to wild type cells. Blocking antibodies against CD30L and OX40L ameliorated nephrotoxic serum nephritis without affecting pan-effector or memory T cell populations. Thus, our results indicate disease promotion via CD30 and OX40 signaling due to facilitation of exaggerated T cell proliferation and migration of T helper 17 cells in nephrotoxic serum nephritis. Hence, co-stimulation blockade targeting the CD30 and OX40 signaling pathways may provide a novel therapeutic strategy in autoimmune kidney disease.

Revisiting the complement system in systemic lupus erythematosus

Introduction: Systemic lupus erythematosus (SLE) is a multi-system autoimmune disease, characterized by the production of autoantibodies. Numerous mechanisms contribute to the pathogenesis and autoimmunity in SLE. One of the most important mechanisms is the defective function of the early complement components that are involved in clearing the immune-complexes and apoptotic debris. Major evidence supporting this hypothesis is the development of severe lupus in individuals with monogenic defects in any one of the early complement components such as C1q, C1 s, C1 r, C2, or C4.Areas covered: In this review, we discuss hereditary defects in classical complement components and their clinical manifestations, acquired defects of complements in lupus, the role of complements in the pathogenesis of antiphospholipid antibody syndrome and lupus nephritis, and laboratory assessment of complement components and their functions. Articles from the last 20 years were retrieved from PubMed for this purpose.Expert opinion: Complements have a dual role in the pathogenesis of SLE. On one hand, deficiency of complement components predisposes to lupus, while, on the other, excess complement activation plays a role in the organ damage. Understanding the intricacies of the role of complements in SLE can pave way for the development of targeted therapies.

Design and evaluation of glomerulus mesangium-targeted PEG-PLGA nanoparticles loaded with dexamethasone acetate

Mesangial proliferative glomerulonephritis (MsPGN), one of the most common glomerulonephritis pathological types, often leads to end-stage renal disease over a prolonged period. But the current treatment of MsPGN is non-specific and causes serious side effects, thus novel therapeutics and targeting strategies are urgently demanded. By combining the advantages of PEG-PLGA nanoparticles and the size selection mechanism of renal glomerulus, we designed and developed a novel PEG-PLGA nanoparticle delivery system capable of delivering dexamethasone acetate (A-DEX) into glomerular mesangium. We determined that 90 nm was the optimum size to encapsulate A-DEX for glomerular mesangium targeting based on the size-selection mechanism of glomerulus. After intravenous administration in rats, 90 nm DiD-loaded NPs were found to accumulate to a greater extent in the kidney and kidney cortex compared with the free DiD solution. The 90 nm A-DEX NPs are also more stable at room temperature and showed a sustained release pattern. In rat glomerular mesangial cells (HBZY-1) in vitro, we found that the uptake of 90 nm A-DEX NPs was both temperature-dependent and energe-dependent, and they were mostly engulfed via clathrin-dependent endocytosis pathways. In summary, we have successfully developed a glomerular mesangium-targeted PEG-PLGA NPs, which is potential for the treatment of MsPGN.

Molecular and genetic aspects of guanylyl cyclase natriuretic peptide receptor-A in regulation of blood pressure and renal function

Natriuretic peptides (NPs) exert diverse effects on several biological and physiological systems, such as kidney function, neural and endocrine signaling, energy metabolism, and cardiovascular function, playing pivotal roles in the regulation of blood pressure (BP) and cardiac and vascular homeostasis. NPs are collectively known as anti-hypertensive hormones and their main functions are directed toward eliciting natriuretic/diuretic, vasorelaxant, anti-proliferative, anti-inflammatory, and anti-hypertrophic effects, thereby, regulating the fluid volume, BP, and renal and cardiovascular conditions. Interactions of NPs with their cognate receptors display a central role in all aspects of cellular, biochemical, and molecular mechanisms that govern physiology and pathophysiology of BP and cardiovascular events. Among the NPs atrial and brain natriuretic peptides (ANP and BNP) activate guanylyl cyclase/natriuretic peptide receptor-A (GC-A/NPRA) and initiate intracellular signaling. The genetic disruption of Npr1 (encoding GC-A/NPRA) in mice exhibits high BP and hypertensive heart disease that is seen in untreated hypertensive subjects, including high BP and heart failure. There has been a surge of interest in the NPs and their receptors and a wealth of information have emerged in the last four decades, including molecular structure, signaling mechanisms, altered phenotypic characterization of transgenic and gene-targeted animal models, and genetic analyses in humans. The major goal of the present review is to emphasize and summarize the critical findings and recent discoveries regarding the molecular and genetic regulation of NPs, physiological metabolic functions, and the signaling of receptor GC-A/NPRA with emphasis on the BP regulation and renal and cardiovascular disorders.

Costimulatory blockade: A novel approach to the treatment of glomerular disease?

Costimulatory pathways (Cluster of differentiation 28, tumor necrosis factor-related, adhesion and T Cell Ig- and mucin-domain molecules) regulating the interactions between receptors on the T cells and their ligands expressed on several cell types, have a key role in controlling many immunological and non immunological processes. Indeed, accumulating evidence indicate that these molecules are involved in the pathogenesis of numerous conditions, such as allograft rejection, atherosclerosis, rheumatoid arthritis, psoriasis and renal diseases, including glomerulonephritis. Primary or secondary (i.e., associated with infections, drugs or systemic diseases, such as systemic lupus erythematosus, diabetes, etc.) glomerulonephritis represent a group of heterogeneous diseases with different pathogenic mechanisms. Since costimulatory molecules, in particular CD80 and CD40, have been found to be expressed on podocytes in the course of different experimental and clinical glomerulonephritis, costimulation has been thought as a new therapeutic target for patients with glomerular diseases. However, although experimental data suggested that the blockade of costimulatory pathways is effective and safe in the prevention and treatment of glomerular diseases, clinical trials reported contrasting results. So, at this moment, there is not a strong evidence for the general use of costimulatory blockade as an alternative treatment strategy in patients with primary or secondary glomerulonephritis. Here, we critically discuss the current data and the main issues regarding the development of this innovative therapeutic approach.

Lupus nephritis susceptibility loci in women with systemic lupus erythematosus

Lupus nephritis is a manifestation of SLE resulting from glomerular immune complex deposition and inflammation. Lupus nephritis demonstrates familial aggregation and accounts for significant morbidity and mortality. We completed a meta-analysis of three genome-wide association studies of SLE to identify lupus nephritis-predisposing loci. Through genotyping and imputation, >1.6 million markers were assessed in 2000 unrelated women of European descent with SLE (588 patients with lupus nephritis and 1412 patients with lupus without nephritis). Tests of association were computed using logistic regression adjusting for population substructure. The strongest evidence for association was observed outside the MHC and included markers localized to 4q11-q13 (PDGFRA, GSX2; P=4.5×10(-7)), 16p12 (SLC5A11; P=5.1×10(-7)), 6p22 (ID4; P=7.4×10(-7)), and 8q24.12 (HAS2, SNTB1; P=1.1×10(-6)). Both HLA-DR2 and HLA-DR3, two well established lupus susceptibility loci, showed evidence of association with lupus nephritis (P=0.06 and P=3.7×10(-5), respectively). Within the class I region, rs9263871 (C6orf15-HCG22) had the strongest evidence of association with lupus nephritis independent of HLA-DR2 and HLA-DR3 (P=8.5×10(-6)). Consistent with a functional role in lupus nephritis, intra-renal mRNA levels of PDGFRA and associated pathway members showed significant enrichment in patients with lupus nephritis (n=32) compared with controls (n=15). Results from this large-scale genome-wide investigation of lupus nephritis provide evidence of multiple biologically relevant lupus nephritis susceptibility loci.

Targeting the sphingosine kinase/sphingosine 1-phosphate pathway to treat chronic inflammatory kidney diseases

Chronic kidney diseases including glomerulonephritis are often accompanied by acute or chronic inflammation that leads to an increase in extracellular matrix (ECM) production and subsequent glomerulosclerosis. Glomerulonephritis is one of the leading causes for end-stage renal failure with high morbidity and mortality, and there are still only a limited number of drugs for treatment available. In this MiniReview, we discuss the possibility of targeting sphingolipids, specifically the sphingosine kinase 1 (SphK1) and sphingosine 1-phosphate (S1P) pathway, as new therapeutic strategy for the treatment of glomerulonephritis, as this pathway was demonstrated to be dysregulated under disease conditions. Sphingosine 1-phosphate is a multifunctional signalling molecule, which was shown to influence several hallmarks of glomerulonephritis including mesangial cell proliferation, renal inflammation and fibrosis. Most importantly, the site of action of S1P determines the final effect on disease progression. Concerning renal fibrosis, extracellular S1P acts pro-fibrotic via activation of cell surface S1P receptors, whereas intracellular S1P was shown to attenuate the fibrotic response. Interference with S1P signalling by treatment with FTY720, an S1P receptor modulator, resulted in beneficial effects in various animal models of chronic kidney diseases. Also, sonepcizumab, a monoclonal anti-S1P antibody that neutralizes extracellular S1P, and a S1P-degrading recombinant S1P lyase are promising new strategies for the treatment of glomerulonephritis. In summary, especially due to the bifunctionality of S1P, the SphK1/S1P pathway provides multiple target sites for the treatment of chronic kidney diseases.

Novel targets for immunotherapy in glomerulonephritis

Glomerulonephritis is a common cause of chronic kidney disease and end stage renal failure. Current therapy relies on variably effective, nonspecific and toxic immunosuppression. Recent insights into underlying biology and disease pathogenesis in human glomerulonephritis combined with advances in the fields of inflammation and autoimmunity promise a cadre of novel targeted interventions. This review highlights the therapeutic potential of two antigens, alpha3 (IV)NC1 collagen and podocyte neutral endopeptidase, and two cell signaling and effector molecules, IgG Fc receptors and complement, judged to be particularly amenable to therapeutic manipulation in man. It is anticipated that continued dissection of pathogenesis in the diverse disorders that comprise the glomerulonephritides will provide the basis for individualized disease-specific therapy.

Anticomplement therapy

The complement system is an important part of innate immunity; however, as with other parts of the immune system, the complement system can become pathologically activated and create or worsen disease. Anticomplement reagents have been studied for several years, but only recently have they emerged as a viable therapeutic tool. Here, we describe the role of the complement system in a wide array of diseases, as well as the use of anticomplement therapy as treatment for these diseases in animal models and in human clinical trials. Specifically, we will discuss the role of anticomplement therapy in paroxysmal nocturnal hemoglobinuria, glomerulonephritis, and heart disease, including coronary artery disease, myocardial infarction, and coronary revascularization procedures such as percutaneous coronary angioplasty and coronary artery bypass graft surgery.

Corticosteroid treatment of kidney disease in a patient with familial lecithin-cholesterol acyltransferase deficiency

Familial lecithin-cholesterol acyltransferase (LCAT) deficiency (FLD) is a rare genetic disorder of lipid metabolism, characterised by low plasma HDL cholesterol, proteinuria, haemolytic anaemia and corneal opacities. Usually renal disease progresses during the third decade of life to renal failure; however the pathogenesis of renal disease is not well understood. In this study we describe treatment of renal disease in two siblings with FLD. The proband WX at the age of 31 years presented proteinuria and ankle oedema during her third pregnancy. Diagnosis of FLD was based on a renal biopsy with characteristic serpiginous fibrillar deposits under electron microscopy, markedly decreased HDL cholesterol, esterified cholesterol levels and LCAT activity, confirmed by molecular analysis. After 3 years her proteinuria increased and she received an ACE inhibitor to which she responded well. During further increases of proteinuria she additionally received methylprednisolone and her proteinuria decreased. This long-term observation indicates the efficacy of corticosteroids and renin-angiotensin-aldosterone system blockers in the treatment of proteinuria in patients with FLD. The results suggest the role of inflammatory processes as well as dyslipidemia in the pathogenesis of glomerular disorders in LCAT-deficient patients.

Relationship between oxidative stress and inflammatory cytokines in diabetic nephropathy

The prevalence of diabetes has dramatically increased worldwide due to the vast increase in the obesity rate. Diabetic nephropathy is one of the major complications of type 1 and type 2 diabetes and it is currently the leading cause of end-stage renal disease. Hyperglycemia is the driving force for the development of diabetic nephropathy. It is well known that hyperglycemia increases the production of free radicals resulting in oxidative stress. While increases in oxidative stress have been shown to contribute to the development and progression of diabetic nephropathy, the mechanisms by which this occurs are still being investigated. Historically, diabetes was not thought to be an immune disease; however, there is increasing evidence supporting a role for inflammation in type 1 and type 2 diabetes. Inflammatory cells, cytokines, and profibrotic growth factors including transforming growth factor-β (TGF-β), monocyte chemoattractant protein-1 (MCP-1), connective tissue growth factor (CTGF), tumor necrosis factor-α (TNF-α), interleukin-1 (IL-1), interleukin-6 (IL-6), interleukin-18 (IL-18), and cell adhesion molecules (CAMs) have all been implicated in the pathogenesis of diabetic nephropathy via increased vascular inflammation and fibrosis. The stimulus for the increase in inflammation in diabetes is still under investigation; however, reactive oxygen species are a primary candidate. Thus, targeting oxidative stress-inflammatory cytokine signaling could improve therapeutic options for diabetic nephropathy. The current review will focus on understanding the relationship between oxidative stress and inflammatory cytokines in diabetic nephropathy to help elucidate the question of which comes first in the progression of diabetic nephropathy, oxidative stress, or inflammation.

Neutrophils: game changers in glomerulonephritis?

Glomerulonephritides represent a diverse array of diseases that have in common immune cell-mediated effector mechanisms that cause organ damage. The contribution of neutrophils to the pathogenesis of proliferative glomerulonephritis (GN) is not well recognized. Most equate neutrophils with killing pathogens and causing collateral tissue damage during acute inflammation. However, these phagocytes are endowed with additional characteristics that have been traditionally reserved for cells of the adaptive immune system. They communicate with other cells, exhibit plasticity in their responses and have the potential to coordinate and inform the subsequent immune response, thus countering the notion that they arrive, destroy and then disappear. Therefore, neutrophils, which are the first to arrive at a site of inflammation, are potential game changers in GN.

Inflammatory cytokines as predictive markers for early detection and progression of diabetic nephropathy

Diabetic nephropathy is a major complication of diabetes mellitus and the leading cause of end-stage renal disease. Both hyperglycemia and hypertension (systemic and/or intraglomerular) are established causal factors for diabetic nephropathy. Nonetheless, there is growing evidence that activated innate immunity and inflammation are also contributing factors to the pathogenesis of diabetic nephropathy. This notion is based on increasing evidence indicating that both cytokines-chemokines and pro-fibrotic growth factors are important players in the progression of diabetic nephropathy, effectively accelerating and exacerbating inflammatory and fibrotic processes leading to end-stage renal disease. In this review, we focus on several predominant cytokines-chemokines as potential predictive markers for diabetic nephropathy. These cytokines-chemokines may also be helpful as biomarkers to monitor the progression of the disease and the impact of interventional modalities aimed at halting eventual manifestation of end-stage renal disease in diabetic patients.

Selective targeting of nanocarriers to neutrophils and monocytes

We previously identified and characterized cell-type selective binding peptides from random peptide phage display libraries. Here, we used one of these peptides (GGP) to target liposomal nanocarriers to leukocyte subsets. To profile the binding selectivity of GGP-coated liposomes to human blood cells, we performed flow cytometric analysis with whole anti-coagulated blood. It is shown that when liposomal nanocarriers present these peptides on their surface, they facilitated cell-type specific targeting of liposomes to neutrophils and monocytes in contrast to nontargeted liposomes. Our data suggest that engineering the appropriate number of targeting peptide ligands on the nanocarrier surface is a factor in cell-binding selectivity, as is dose. Increasing the peptide density on the surface of the liposomes from 250 to 500 molecules resulted in more binding to neutrophils and monocytes. Fluorescence confocal microscopy corroborated the flow cytometry data revealing that liposomes coated with targeting GGP peptides decorated the surface of targeting cells and facilitate cell uptake of payload as evidenced by nuclear localization of tracer. These data suggest that small peptides identified by phage display techniques can be used to target nanocarriers that potentially carry therapeutic or imaging agents to leukocyte subsets. This ability has important implications for diseases where neutrophils and monocytes play a major role such as arthritis, inflammatory bowel disease, chronic obstructive pulmonary disease, and glomerulonephritis.

Novel therapeutics for systemic lupus erythematosus

PURPOSE OF REVIEW

This review provides an update on recently explored therapies in systemic lupus erythematosus and introduces novel therapeutic approaches under consideration. Recent advances in our understanding of systemic lupus are highlighted as well, as these must now inform consideration of therapeutics.

RECENT FINDINGS

Many therapeutic strategies have been shown to be beneficial in murine models of lupus. Compounds that inhibit cellular signaling in response to autoantigens or other triggers and protocols that reconstitute the immune repertoire to diminish autoreactivity are now entering clinical trials.

SUMMARY

Requirements for novel approaches in lupus include improved efficacy and lower toxicity than current therapies, with the goal to reduce tissue damage while preserving immunocompetence.

Inhibition of proinflammatory genes in anti-GBM glomerulonephritis by targeted dexamethasone-loaded AbEsel liposomes

E-selectin-directed targeted drug delivery was analyzed in anti-glomerular basement membrane glomerulonephritis. Liposomes conjugated with anti-E-selectin antibodies (AbEsel liposomes) were internalized by activated endothelial cells in vitro through E-selectin-mediated endocytosis. At the onset of glomerulonephritis in mice, E-selectin was expressed on glomerular endothelial cells, which resulted in homing of AbEsel liposomes to glomeruli after intravenous administration. Accumulation of AbEsel liposomes in the kidney was 3.6 times higher than nontargeted IgG liposomes, whereas the accumulation of both liposomes in the clearance organs liver and spleen and in heart and lungs was comparable. In glomeruli, the AbEsel liposomes colocalized with the endothelial cell marker CD31. Quantitative RT-PCR analysis of laser-microdissected arterioles, glomeruli, and postcapillary venules demonstrated that targeted delivery of dexamethasone by AbEsel liposomes reduced glomerular endothelial expression of P-selectin, E-selectin, and vascular cell adhesion molecule-1 by 60–70%. The expression of these genes was not modulated in endothelial cells in nontargeted renal microvasculatures. Decrease of glomerular endothelial activation at disease onset was followed by reduced albuminuria at day 7. This study demonstrates the potential of vascular bed-specific drug delivery aimed at disease-induced epitopes on the microvascular endothelial cells as a therapeutic strategy for glomerulonephritis.

Nuclear factor of activated T cells (NFAT) mediates CD154 expression in megakaryocytes

Platelets are an abundant source of CD40 ligand (CD154), an immunomodulatory and proinflammatory molecule implicated in the onset and progression of several inflammatory diseases, including systemic lupus erythematosus (SLE), diabetes, and cardiovascular disease. Heretofore considered largely restricted to activated T cells, we initiated studies to investigate the source and regulation of platelet-associated CD154. We found that CD154 is abundantly expressed in platelet precursor cells, megakaryocytes. We show that CD154 is expressed in primary human CD34+ and murine hematopoietic precursor cells only after cytokine-driven megakaryocyte differentiation. Furthermore, using several established megakaryocyte-like cells lines, we performed promoter analysis of the CD154 gene and found that NFAT, a calcium-dependent transcriptional regulator associated with activated T cells, mediated both differentiation-dependent and inducible megakaryocyte-specific CD154 expression. Overall, these data represent the first investigation of the regulation of a novel source of CD154 and suggests that platelet-associated CD154 can be biochemically modulated.

Rituximab Treatment of Dysproteinemias Affecting the Kidney: A Review of Three Cases

The renal diseases associated with monoclonal immunoglobulin deposits constitute a diverse range of clinical and pathological entities. Renal prognosis is variable, and there currently are no standard treatment regimens. We describe the effect of rituximab treatment on 3 patients with renal insufficiency and proteinuria with monoclonal immunoglobulin deposits associated with glomerulonephritis on renal biopsy. Two patients with hypertension and chronic lymphocytic leukemia had a membranoproliferative glomerulonephritis pattern on kidney biopsy associated with monoclonal immunoglobulin G deposits. Both patients experienced partial remission of their disease and 1 patient was able to come off hemodialysis therapy after treatment with 7 and 11 biweekly doses of rituximab, 375 mg/m(2), in addition to angiotensin-converting enzyme inhibitor and angiotensin receptor blocker. Both patients subsequently experienced relapse of their hematologic and renal diseases and eventually progressed to end-stage renal disease and death. A third patient had diffuse proliferative glomerulonephritis with immunoglobulin G lambda deposits on renal biopsy. She was treated with an angiotensin receptor blocker and two 1,000-mg infusions of rituximab separated by 2 weeks, with sustained partial remission at 18 months' follow-up. Rituximab therapy, in addition to corticosteroids and angiotensin blockade, may improve the clinical course of patients with renal diseases associated with dysproteinemias, delaying the onset of end-stage renal failure or other adverse outcomes. Additional clinical studies should be planned.

Adenosine A2A receptor activation and macrophage-mediated experimental glomerulonephritis

In immune-induced inflammation, leukocytes are key mediators of tissue damage. Since A(2A) adenosine receptors (A(2A)Rs) are endogenous suppressors of inflammation, we examined cellular and molecular mechanisms of kidney damage to determine if selective activation of A(2A)R would suppress inflammation in a rat model of glomerulonephritis. Activation of A(2A)R reduced the degree of kidney injury in both the acute inflammatory phase and the progressive phase of glomerulonephritis. This protection against acute and chronic inflammation was associated with suppression of the glomerular expression of the MDC/CCL22 chemokine and down-regulation of MIP-1alpha/CCL3, RANTES/CCL5, MIP-1beta/CCL4, and MCP-1/CCL2 chemokines. The expression of anti-inflammatory cytokines, interluekin (IL)-4 and IL-10, also increased. The mechanism for these anti-inflammatory responses to the A(2A)R agonist was suppression of macrophages function. A(2A)R expression was increased in macrophages, macrophage-derived chemokines were reduced in response to the A(2A)R agonist, and chemokines not expressed in macrophages did not respond to A(2A)R activation. Thus, activation of the A(2A)R on macrophages inhibits immune-associated inflammation. In glomerulonephritis, A(2A)R activation modulates inflammation and tissue damage even in the progressive phase of glomerulonephritis. Accordingly, pharmacological activation of A(2A)R could be developed into a novel treatment for glomerulonephritis and other macrophage-related inflammatory diseases.

Functions of TNF and its receptors in renal disease: distinct roles in inflammatory tissue injury and immune regulation

Tumor necrosis factor (TNF) alpha is a potent proinflammatory cytokine and important mediator of inflammatory tissue damage. In addition, it has important immune-regulatory functions. Many experimental studies and clinical observations support a role for TNF in the pathogenesis of acute and chronic renal disease. However, given its dual functions in inflammation and immune regulation, TNF may mediate both proinflammatory as well as immunosuppressive effects, particularly in chronic kidney diseases and systemic autoimmunity. Blockade of TNF in human rheumatoid arthritis or Crohn's disease led to the development of autoantibodies, lupus-like syndrome, and glomerulonephritis in some patients. These data raise concern about using TNF-blocking therapies in renal disease because the kidney may be especially vulnerable to the manifestation of autoimmune processes. Interestingly, recent experimental evidence suggests distinct roles for the 2 TNF receptors in mediating local inflammatory injury in the kidney and systemic immune-regulatory functions. In this review the biologic properties of TNF and its receptors, TNF receptors 1 and 2, relevant to kidney disease are summarized followed by a review of the available experimental and clinical data on the pathogenic role of the TNF system in nonimmune and immune renal diseases. Experimental evidence also is reviewed that supports a rationale for specifically blocking TNF receptor 2 versus anti-TNF therapies in some nephropathies, including immune complex-mediated glomerulonephritis.

Site-specific inhibition of glomerulonephritis progression by targeted delivery of dexamethasone to glomerular endothelium

Glomerulonephritis represents a group of renal diseases with glomerular inflammation as a common pathologic finding. Because of the underlying immunologic character of these disorders, they are frequently treated with glucocorticoids and cytotoxic immunosuppressive agents. Although effective, use of these compounds has limitations as a result of toxicity and systemic side effects. In the current study, we tested the hypothesis that targeted delivery of dexamethasone (dexa) by immunoliposomes to activated glomerular endothelium decreases renal injury but prevents its systemic side effects. E-selectin was chosen as a target molecule based on its disease-specific expression on activated glomerular endothelium in a mouse anti-glomerular basement membrane glomerulonephritis. Site-selective delivery of Ab(Esel) liposome-encapsulated dexamethasone strongly reduced glomerular proinflammatory gene expression without affecting blood glucose levels, a severe side effect of administration of free dexamethasone. Dexa-Ab(Esel) liposomes reduced renal injury as shown by a reduction of blood urea nitrogen levels, decreased glomerular crescent formation, and down-regulation of disease-associated genes. Immunoliposomal drug delivery to glomerular endothelium presents a powerful new strategy for treatment of glomerulonephritis to sustain efficacy and prevent side effects of potent anti-inflammatory drugs.

Chemokines and Chemokine Receptors as Therapeutic Targets in Lupus Nephritis

Recruitment of leukocytes is a characteristic feature of tissue injury in systemic lupus erythematosus, including lupus nephritis. Locally secreted chemokines and their receptors are important mediators of leukocyte recruitment to the specific sites of immune complex injury, and contribute to renal inflammatory disease in the initiation and progression phase. Therefore, chemokines and chemokine receptors represent potential therapeutic targets in lupus nephritis. In this review we summarize available experimental and human data supporting their functional role in lupus nephritis. Moreover, interventional studies with chemokine and chemokine receptor antagonists that show the therapeutic potential of chemokine antagonists in experimental models of lupus nephritis and potentially in human renal disease are discussed.

Review of autoimmune (lupus-like) glomerulonephritis in murine models

While murine models of autoimmune (lupus-like) glomerulonephritis have been available for sometime, it is only recently that immune and inflammatory mechanisms and molecular genetics have been extensively investigated. Genes involved in murine and human lupus nephritis have been discovered and provide insight into this disease process and provide avenues for molecular-targeted therapy. Immune modulation of murine nephritis has provided insight into novel therapy that may attenuate this disease or halt disease progression. With the advances in understanding the pathogenesis of lupus nephritis using translational research modalities, including electron microscopy, and molecular genetics, many "designer" therapies have become available for clinical use and for clinical investigational trials. This paper reviews autoimmune (lupus-like) glomerulonephritis in murine models, candidate genes involved in lupus nephritis, adhesion molecules implicated in murine lupus-like nephritis, immune modulation of murine lupus-like nephritis, and novel and potential therapy for immune complex glomerulonephritis.

Imatinib ameliorates renal disease and survival in murine lupus autoimmune disease

Platelet-derived growth factor (PDGF) has been proved to play an important role in progressive glomerular disease of systemic lupus. The present study investigated the tyrosine kinase inhibitor of PDGF receptor, imatinib, as a novel therapeutic approach for the cure of lupus nephritis in New Zealand Black/White (NZB/W)F1 hybrid mice with established disease. Two groups of NZB/W mice (N=30 each group), starting at 5 months of age, were given by gavage vehicle or imatinib (50 mg/kg b.i.d). Fifteen mice for each group were used for the survival study. The remaining were killed at 8 months. Imatinib significantly (P=0.0022) ameliorated animal survival with respect to vehicle. The drug significantly delayed the onset of proteinuria (% proteinuric mice, 7 and 8 months: 33 and 47 vs vehicle, 80 and 87, P<0.05) and limited the impairment of renal function. Imatinib protected the kidney against glomerular hypercellularity and deposits, tubulointerstitial damage, and accumulation of F4/80-positive mononuclear cells and alpha-smooth actin-positive myofibroblasts. The abnormal transforming growth factor-beta mRNA expression in kidneys of lupus mice was reduced by imatinib. In conclusion, findings of amelioration of animal survival and renal manifestations in NZB/W lupus mice with established disease by imatinib suggests the possibility to explore whether imatinib may function as steroid-sparing drug in human lupus nephritis.

Therapeutics in renal disease: the road ahead for antiproliferative targets

Discovery into the molecular basis of renal disease is occurring at an unprecedented rate. With the advent of the NIH Roadmap, there is a greater expectation of translating this knowledge into new treatments. Here, we review the therapeutic strategy to preserve renal function in proliferative renal diseases by directly inhibiting the mitogenic pathways within renal parenchymal cells that promote G0 to G1/S cell-cycle phase progression. Reductionist methodologies have identified several antiproliferative molecular targets, and promising preclinical testing of leading small-molecule drugs to modulate these targets has now led to landmark clinical trials. Yet, this advancement into targeted therapy highlights important differences between the therapeutic goals of molecular nephrology versus molecular oncology and, by extension, the poorly understood role of alternative target activity in drug efficacy. Systems research to clarify these issues should accelerate the development of this promising therapeutic strategy.