Depletion of CD4(+) T cells aggravates glomerular and interstitial injury in murine adriamycin nephropathy

Immunoregulatory effects of Huaier (Trametes robiniophila Murr) and relevant clinical applications

Huaier (Trametes robiniophila Murr) is a medicinal fungus of traditional Chinese medicine with more than 1000 years of history of clinical application. Its remarkable anticancer activities has led to its application in treating diverse malignancies. In recent years, the immunomodulatory effects of Huaier have been uncovered and proved to be beneficial in a plethora of immune-related diseases including cancer, nephropathy, asthma, etc. In this review, we comprehensively summarized the active components of Huaier, its regulatory activities on multifaceted aspects of the immune system, its application in various clinical settings as well as toxicologic evidence. Based on currently available literature, Huaier possesses broad-spectrum regulatory activities on various components of the innate and adaptive immune system, including macrophages, dendritic cells, natural killer cells, T and B lymphocytes, etc. Versatile immunologic reactions are under the regulation of Huaier from expression of damage-associated molecular patterns, immune cell activation and maturation to cell proliferation, differentiation, antibody production, expression of cytokines and chemokines and terminal intracellular signal transduction. Moreover, some modulatory activities of Huaier might be context-dependent, typically promoting the restoration toward normal physiological status. With excellent efficacy and minimal side effects, we foresee more extensive application of Huaier for treating immune-related disorders.

Immunophenotypic Alterations in Adult Patients with Steroid-Dependent and Frequently Relapsing Nephrotic Syndrome

Immune dysregulation plays a key role in the pathogenesis of steroid-dependent/frequently relapsing nephrotic syndrome (SDNS/FRNS). However, in contrast with evidence from the pediatric series, no major B- or T-cell alterations have been described for adults. In these patients, treatment with rituximab allows safe discontinuation of steroids, but long-term efficacy is variable, and some patients experience NS relapses after B cell reconstitution. In this study, we aimed to determine disease-associated changes in the B and T cell phenotype of adult patients with SDND/FRNS after steroid-induced remission. We also investigated whether any of these changes in immune cell subsets could discriminate between patients who developed NS relapses after steroid-sparing treatment with rituximab from those who did not. Lymphocyte subsets in SDNS/FRNS patients (n = 18) were compared to those from patients with steroid-resistant NS (SRNS, n = 7) and healthy volunteers (HV, n = 15). Before rituximab, SDND/FRNS patients showed increased frequencies of total and memory B cells, mainly with a CD38-negative phenotype. Within the T-cell compartment, significantly lower levels of FOXP3⁺ regulatory T cells (Tregs) were found, mostly due to a reduction in CD45RO⁺ memory Tregs compared to both SRNS and HV. The levels of CD45RO⁺ Tregs were significantly lower at baseline in patients who relapsed after rituximab (n = 9) compared to patients who did not (n = 9). In conclusion, patients with SDND/FRNS displayed expansion of memory B cells and reduced memory Tregs. Treg levels at baseline may help identify patients who will achieve sustained remission following rituximab infusion from those who will experience NS relapses.

The role of thyroid hormone in the renal immune microenvironment

Thyroid hormones are essential for proper kidney growth and development. The kidney is not only the organ of thyroid hormone metabolism but also the target organ of thyroid hormone. Kidney disease is a common type of kidney damage, mainly including different types of acute kidney injury, chronic kidney disease, diabetic nephropathy, lupus nephritis, and renal cell carcinoma. The kidney is often damaged by an immune response directed against its antigens or a systemic immune response. A variety of immune cells in the innate and adaptive immune systems, including neutrophils, macrophages, dendritic cells, T lymphocytes, and B lymphocytes, is essential for maintaining immune homeostasis and preventing autoimmune kidney disease. Recent studies have found that thyroid hormone plays an indispensable role in the immune microenvironment of various kidney diseases. Thyroid hormones regulate the activity of neutrophils, and dendritic cells express triiodothyronine receptors. Compared to hypothyroidism, hyperthyroidism has a greater effect on neutrophils. Furthermore, in adaptive immune systems, thyroid hormone may activate T lymphocytes through several underlying mechanisms, such as mediating NF-κB, protein kinase C signalling pathways, and β-adrenergic receptors, leading to increased T lymphocyte activation. The present review discusses the effects of thyroid hormone metabolism regulation in the immune microenvironment on the function of various immune cells, especially neutrophils, macrophages, dendritic cells, T lymphocytes, and B lymphocytes. Although there are not enough data at this stage to conclude the clinical relevance of these findings, thyroid hormone metabolism may influence autoimmune kidney disease by regulating the renal immune microenvironment.

A Deep Insight Into Regulatory T Cell Metabolism in Renal Disease: Facts and Perspectives

Kidney disease encompasses a complex set of diseases that can aggravate or start systemic pathophysiological processes through their complex metabolic mechanisms and effects on body homoeostasis. The prevalence of kidney disease has increased dramatically over the last two decades. CD4⁺CD25⁺ regulatory T (Treg) cells that express the transcription factor forkhead box protein 3 (Foxp3) are critical for maintaining immune homeostasis and preventing autoimmune disease and tissue damage caused by excessive or unnecessary immune activation, including autoimmune kidney diseases. Recent studies have highlighted the critical role of metabolic reprogramming in controlling the plasticity, stability, and function of Treg cells. They are also likely to play a vital role in limiting kidney transplant rejection and potentially promoting transplant tolerance. Metabolic pathways, such as mitochondrial function, glycolysis, lipid synthesis, glutaminolysis, and mammalian target of rapamycin (mTOR) activation, are involved in the development of renal diseases by modulating the function and proliferation of Treg cells. Targeting metabolic pathways to alter Treg cells can offer a promising method for renal disease therapy. In this review, we provide a new perspective on the role of Treg cell metabolism in renal diseases by presenting the renal microenvironment、relevant metabolites of Treg cell metabolism, and the role of Treg cell metabolism in various kidney diseases.

The role of the immune system in idiopathic nephrotic syndrome

Idiopathic nephrotic syndrome (INS) in children is characterized by massive proteinuria and hypoalbuminemia and usually responds well to steroids. However, relapses are frequent, which can require multi-drug therapy with deleterious long-term side effects. In the last decades, different hypotheses on molecular mechanisms underlying INS have been proposed and several lines of evidences strongly indicate a crucial role of the immune system in the pathogenesis of non-genetic INS. INS is traditionally considered a T-cell-mediated disorder triggered by a circulating factor, which causes the impairment of the glomerular filtration barrier and subsequent proteinuria. Additionally, the imbalance between Th17/Tregs as well as Th2/Th1 has been implicated in the pathomechanism of INS. Interestingly, B-cells have gained attention, since rituximab, an anti-CD20 antibody demonstrated a good therapeutic response in the treatment of INS. Finally, recent findings indicate that even podocytes can act as antigen-presenting cells under inflammatory stimuli and play a direct role in activating cellular pathways that cause proteinuria. Even though our knowledge on the underlying mechanisms of INS is still incomplete, it became clear that instead of a traditionally implicated cell subset or one particular molecule as a causative factor for INS, a multi-step control system including soluble factors, immune cells, and podocytes is necessary to prevent the occurrence of INS. This present review aims to provide an overview of the current knowledge on this topic, since advances in our understanding of the immunopathogenesis of INS may help drive new tailored therapeutic approaches forward.

Baicalin attenuates adriamycin-induced nephrotic syndrome by regulating fibrosis procession and inflammatory reaction

BACKGROUND

Baicalin has anti-inflammatory, antibacterial, blood platelet aggregation-inhibiting, free oxygen radical-clearing, and endotoxin-decreasing properties. However, its molecular mechanism involved in the treatment of Adriamycin-induced nephrotic syndrome (NS) is still unclear.

OBJECTIVE

This study aimed to explore the effects of baicalin on Adriamycin-induced nephrotic syndrome (NS) and to characterize the genes involved in this progression.

METHODS

We established Adriamycin-induced NS model in 32 rats and used six rats in Sham group. Urinary total protein content and creatinine serum were assessed as physiological indicators. H&E staining was used to observe the pathological changes. We determined gene expression profiles using transcriptome sequencing in the rat kidney tissues from Sham, Adriamycin, and Adriamycin + baicalin groups. KEGG was carried out to analyze the enriched pathways of differentially expressed genes among these groups.

RESULTS

Baicalin treatment relieved renal injury in NS rats. Expression of 363 genes was significantly different between the Adriamycin and Adriamycin + baicalin M groups. Most of the differentially expressed genes were enriched in pathways involved in epithelial-mesenchymal transition (EMT), fibrosis, apoptosis, and inflammation.

CONCLUSIONS

Overall, these data suggest that Adriamycin-induced NS can be attenuated by baicalin through the suppression of fibrosis-related genes and inflammatory reactions. Baicalin is a potential drug candidate for the treatment of NS, and the identified genes represent potential therapeutic targets.

Efficacy and safety of Huaiqihuang granule as adjuvant treatment for primary nephrotic syndrome in children: a meta-analysis and systematic review

BACKGROUND

Huaiqihuang (HQH) granule is a traditional Chinese herbal complex that has been used as an adjuvant treatment in clinics for the primary nephrotic syndrome (PNS) for many years. However, the effectiveness and safety of HQH have not been systematically discussed. This review aimed to evaluate the effectiveness and safety of HQH in paediatric patients with PNS.

METHODS

The following databases were searched from inception to Mar 2019: MEDLINE, Cochrane Library, EMBASE, CNKI, Wanfang Database, the Chinese Scientific Journal Database and the Chinese biomedical literature service system. All the randomized controlled trials (RCTs) eligible for inclusion were included. The primary outcomes were relapse, infection, remission and adverse events. The secondary outcomes included serum immunoglobulin levels (IgA, IgG or IgM), T-lymphocyte subtype (CD3+ , CD4+ , CD8+ , CD4+ /CD8+), IL-10, TNF-α, TNF-γ, total cholesterol and time of proteinuria turning negative.

RESULTS

Fourteen RCTs (885 patients) were identified. Treatment with HQH reduced the chance of relapse [relative risk (RR): 0.47; 95% CI: 0.34, 0.66; P < 0.001] and infections (RR: 0.47; 95% CI: 0.35, 0.62; P < 0.001). No significant difference was found in adverse events. HQH also increased the serum levels of IgA [weighted mean difference (WMD): 0.40; 95% CI: 0.20, 0.60; P < 0.001] and IgG (WMD: 1.58; 95% CI: 1.38-1.78; P < 0.001), as well as CD4+ [standard mean difference (SMD): 0.90; 95% CI: 0.12-1.68; P = 0.02], CD3+ (WMD: 4.04; 95% CI: 3.27-4.82; P < 0.001), and the CD4+/CD8+ratio (WMD: 0.31; 95% CI: 0.21-0.41; P < 0.001), but decreased the level of CD8+ cells (WMD: -3.39; 95% CI: -5.73-1.05; P = 0.004). No statistically significant difference was found in IgM (WMD: 0.05; 95% CI: -0.13, 0.24; P = 0.57).

CONCLUSIONS

HQH could reduce the rate of relapse and the frequency of infection in children with PNS. No apparent adverse effects were found. Moreover, the beneficial influence of HQH may act through immunomodulation. Additional multi-center, large-sample, high-quality studies are needed to confirm the effectiveness and safety of HQH.

Rhodojaponin II attenuates kidney injury by regulating TGF-β1/Smad pathway in mice with adriamycin nephropathy

ETHNOPHARMACOLOGICAL RELEVANCE

Rhododendron molle G. Don (Ericaceae) (RM) is a natural medicinal plant. Its root extracts have been applied in clinic and proved to be effective in chronic glomerulonephritis and rheumatoid arthritis in China. Surprising, little is understood about the key compound of RM and the exact mechanisms underlying its treatment on kidney diseases. In this study, we will explore whether rhodojaponin II (R-II), as the important compound of RM, also exerts the major effect.

MATERIALS AND METHODS

Mouse model of focal segmental glomerulosclerosis was induced by single dose of adriamycin injection. Induced adriamycin nephropathy (ADRN) mice were treated individually with RM root extract (5 mg/kg, n = 5), RM root extract (60 mg/kg, n = 5), R-II (0.04 mg/kg, n = 6) or captopril (30 mg/kg, n = 5) for five weeks. Podocyte marker (nephrin and podocin) expressions were examined by immunohistochemical staining and Western Blot analysis. Fibronectin level was evaluated by immunohistochemical staining and Western Blot analysis. Interstitial infiltrated inflammatory cells (CD4⁺ T cells, CD8⁺ T cells, and CD68⁺ macrophages) were examined with immunohistochemical staining. The expressions of NF-ĸB p-p65 and TGF-β1/Smad pathway associated key proteins, such as TGF-β1, Smad3, phosphorylated-Smad3 (p-Smad3), and Smad7, were analyzed respectively by Western Blot analysis.

RESULTS

RM root extract (5 mg/kg) and its important compound R-II (0.04 mg/kg) significantly ameliorated proteinuria, podocyte injury, and glomerulosclerosis, meanwhile, they hampered interstitial fibrosis in mice with ADRN. R-II significantly reduced NF-ĸB p65 phosphorylation, interstitial infiltrated CD4⁺ T cells, CD8⁺ T cells, and CD68⁺ macrophages, at the same time, down-regulated TGF-β1 and p-Smad3 protein expressions in mice with ADRN.

CONCLUSION

RM root extract, R-II, could effectively ameliorate proteinuria and kidney injury in ADRN, related to its anti-inflammatory effects, as well as suppression of TGF-β1/Smad signaling pathway.

Pediatric Patients With Steroid-Sensitive Nephrotic Syndrome Have Higher Expression of T Regulatory Lymphocytes in Comparison to Steroid-Resistant Disease

Background and Aim: Idiopathic nephrotic syndrome (INS) is classified according to the response to drug therapy in steroid-sensitive (SS), steroid-dependent (SD), and steroid-resistant (SR) categories. Previous studies showed changes in inflammatory activity of subpopulations of lymphocytes in INS. This study aimed to compare SS and SR patients in regard to subpopulations of leukocytes, profile of regulatory lymphocytes, and migratory activity of lymphocyte subpopulations. Results obtained in INS patients were also compared to age and sex-matched healthy controls. Methods: This is a cross-sectional study including SS patients (n = 30), SR patients (n = 14), and controls (n = 10). Peripheral blood samples were withdrawn for ex-vivo leukocyte flow cytometry analysis. Results: Percentage of B-lymphocytes and natural killer (NK) cells were significantly reduced in SR patients when compared to controls, while the percentage of NKT cells were decreased in SS patients in comparison to controls. Percentages of CD4⁺ expressing FoxP3 and CTLA4 were significantly higher in SS patients in comparison to SR patients and controls. The expression of integrin CD18 on the surface of T lymphocytes (CD3⁺) was reduced in SS patients if compared to controls. Conclusion: This study found that SS INS patients have higher levels of regulatory T-lymphocytes and lower expression of adhesion molecules than SR patients.

T-lymphocyte-expressing inflammatory cytokines underlie persistence of proteinuria in children with idiopathic nephrotic syndrome

OBJECTIVE

There is evidence of an important role of immune system changes in the triggering and maintenance of idiopathic nephrotic syndrome (INS). The aim of this study was to investigate the expression of cytokines in lymphocyte populations of patients with INS in comparison to healthy individuals, according to proteinuria.

METHODS

This cross-sectional study included 44 patients with INS and eight healthy children, matched for age and sex (controls). Patients were subdivided according to proteinuria: persistent proteinuria or partial remission (PP≥300mg/24h, n=17) and low proteinuria or complete remission (LP<300mg/24h, n=27). Ex vivo analysis of peripheral blood leukocytes by flow cytometry was performed using surface markers for T-lymphocytes, TCD4, TCD8, natural killer (NK) cells, NKT, and B-lymphocytes. Frequencies of intracellular cytokines were analyzed in these cells.

RESULTS

The frequencies of B-lymphocytes, NK cells, and NKT cells were lower in INS than in controls, whereas INS patients had a higher frequency of CD4⁺tumor necrosis factor (TNF)-α⁺ cells than controls. Cytotoxic-T-lymphocytes expressing IFN-γ were lower in INS than in controls. Patients with PP showed higher frequencies of CD4-T-lymphocytes expressing IFN-γ and TNF-α than controls. CD8-lymphocytes expressing TNF-α were increased in PP group when compared with LP and controls, while CD8⁺interferon (IFN)-γ⁺ cells were lower than in LP and in controls.

CONCLUSION

Regardless the level of proteinuria, INS patients had increased expression of TNF-α in CD4-lymphocytes and reduced expression of IFN-γ in CD8-lymphocytes. Persistence of proteinuria was associated with higher levels of inflammatory markers.

Immunology of idiopathic nephrotic syndrome

The pathogenesis of idiopathic nephrotic syndrome (INS) is as yet unknown, but several lines of evidence indicate that the immune system may play a crucial pathogenic role in non-genetic INS. The most important of these are, first, the effectiveness of therapy based on immunosuppression and, second, a vast body of data derived both from experimental models and from patient studies that implicate T cells and more recently B cells as major players in INS pathogenesis. However, recent findings also suggest a direct role of podocytes as drivers of the disease process, and the interplay between the glomerulus and the immune system is still being elucidated. In this review we provide an overview of current knowledge on the role of different components of the immune system in determining disease. Advances in our understanding of the pathogenesis of INS may help drive new, more tailored therapeutic approaches.

CD4+ and CD8+ T Cells Exert Regulatory Properties During Experimental Acute Aristolochic Acid Nephropathy

Experimental aristolochic acid nephropathy is characterized by transient acute proximal tubule necrosis and inflammatory cell infiltrates followed by interstitial fibrosis and tubular atrophy. The respective role of T-cell subpopulations has never been studied in the acute phase of the mouse model, and was heretofore exclusively investigated by the use of several depletion protocols. As compared to mice injected with aristolochic acids alone, more severe acute kidney injury was observed after CD4⁺ or CD8⁺ T-cells depletion. TNF-alpha and MCP-1 mRNA renal expressions were also increased. In contrast, regulatory T-cells depletion did not modify the severity of the aristolochic acids induced acute kidney injury, suggesting an independent mechanism. Aristolochic acids nephropathy was also associated with an increased proportion of myeloid CD11b^highF4/80^mid and a decreased proportion of their counterpart CD11b^lowF4/80^high population. After CD4⁺ T-cell depletion the increase in the CD11b^highF4/80^mid population was even higher whereas the decrease in the CD11b^lowF4/80^high population was more marked after CD8+ T cells depletion. Our results suggest that CD4⁺ and CD8⁺ T-cells provide protection against AA-induced acute tubular necrosis. Interestingly, T-cell depletion was associated with an imbalance of the CD11b^highF4/80^mid and CD11b^lowF4/80^high populations.

Early intervention with mesenchymal stem cells prevents nephropathy in diabetic rats by ameliorating the inflammatory microenvironment

Diabetic nephropathy (DN) is a major complication of diabetes and represents the leading cause of end-stage renal disease. Mesenchymal stem cell (MSC) treatment has been demonstrated to be effective in DN models by reducing albuminuria and attenuating glomerular injury; however, limited in-depth understanding of the underlying mechanism and a lack of clinical trials hinders its clinical use. Additionally, most of these experimental studies were conducted on the advanced stage of nephropathy, which is difficult to reverse and consequently showed limited therapeutic efficacy. We sought to evaluate whether early intervention by MSCs has the potential to prevent DN onset and progression as well as protect kidney function when intravenously administered to rats with diabetes. Diabetes was induced in adult male SD rats by streptozotocin (STZ) injection (55 mg/kg, i.p.). The diabetic rats were injected with or without bone marrow-derived MSCs (5×10⁶ per rat), via tail vein at 2, 4, 5 and 7 weeks after diabetes onset. Fasting blood glucose (FBG), blood urea nitrogen (BUN) and serum creatinine (Scr) levels in serum samples and glycosuria (GLU), microalbumin (MAU), and albumin to creatinine ratio (ACR) in urine samples were determined. Renal pathology and immunohistochemistry (IHC) for CD68, MCP-1, fibronectin (FN), transforming growth factor-β (TGF-β) and pro-inflammatory cytokines were also performed. Expression levels of the above factors as well as interleukin-10 (IL-10), and epidermal growth factor (EGF) were assessed by qPCR and multiplex bead-based suspension array system, respectively. Additionally, MSC tracing in vivo was performed. Ex vivo, peritoneal macrophages were co-cultured with MSCs, and expression of inflammatory cytokines was detected as well. MSC treatment profoundly suppressed renal macrophage infiltration and inflammatory cytokine secretion in diabetic rats, resulting in prominently improved kidney histology, systemic homeostasis, and animal survival, although no significant effect on hyperglycemia was observed. Engrafted MSCs were primarily localized in deteriorated areas of the kidney and immune organs 48 h after infusion. MSC treatment upregulated serum anti-inflammatory cytokines IL-10 and EGF. Ex vivo, MSCs inhibited lipopolysaccharide (LPS)-stimulated rat peritoneal macrophage activation via the downregulation of inflammatory-related cytokines such as IL-6, MCP-1, tumor necrosis factor-α (TNF-α) and IL-1β. Our results demonstrated that early intervention with MSCs prevented renal injury via immune regulation in diabetic rats, which restored the homeostasis of the immune microenvironment, contributing to the prevention of kidney dysfunction and glomerulosclerosis.

Regulatory T cells in renal disease

The kidney is vulnerable to injury, both acute and chronic from a variety of immune and metabolic insults, all of which at least to some degree involve inflammation. Regulatory T cells modulate systemic autoimmune and allogenic responses in glomerulonephritis and transplantation. Intrarenal regulatory T cells (Tregs), including those recruited to the kidney, have suppressive effects on both adaptive and innate immune cells, and probably also intrinsic kidney cells. Evidence from autoimmune glomerulonephritis implicates antigen-specific Tregs in HLA-mediated dominant protection, while in several human renal diseases Tregs are abnormal in number or phenotype. Experimentally, Tregs can protect the kidney from injury in a variety of renal diseases. Mechanisms of Treg recruitment to the kidney include via the chemokine receptors CCR6 and CXCR3 and potentially, at least in innate injury TLR9. The effects of Tregs may be context dependent, with evidence for roles for immunoregulatory roles both for endogenous Tbet-expressing Tregs and STAT-3-expressing Tregs in experimental glomerulonephritis. Most experimental work and some of the ongoing human trials in renal transplantation have focussed on unfractionated thymically derived Tregs (tTregs). However, induced Tregs (iTregs), type 1 regulatory T (Tr1) cells and in particular antigen-specific Tregs also have therapeutic potential not only in renal transplantation, but also in other kidney diseases.

Phenotypic and functional characterization of mesenchymal stromal cells isolated from pediatric patients with severe idiopathic nephrotic syndrome

BACKGROUND

Idiopathic nephrotic syndrome (INS) is one of the most common renal diseases in the pediatric population; considering the role of the immune system in its pathogenesis, corticosteroids are used as first-line immunosuppressive treatment. Due to its chronic nature and tendency to relapse, a significant proportion of children experience co-morbidity due to prolonged exposure to corticosteroids and concomitant immunosuppression with second-line, steroid-sparing agents. Mesenchymal stromal cells (MSCs) are multipotent cells that represent a key component of the bone marrow (BM) microenvironment; given their unique immunoregulatory properties, their clinical use may be exploited as an alternative therapeutic approach in INS treatment.

METHODS

In view of the possibility of exploiting their immunoregulatory properties, we performed a phenotypical and functional characterization of MSCs isolated from BM of five INS patients (INS-MSCs; median age, 13 years; range, 11-16 years) in comparison with MSCs isolated from eight healthy donors (HD-MSCs). MSCs were expanded ex vivo and then analyzed for their properties.

RESULTS

Morphology, proliferative capacity, immunophenotype and differentiation potential did not differ between INS-MSCs and HD-MSCs. In an allogeneic setting, INS-MSCs were able to prevent both T- and B-cell proliferation and plasma-cell differentiation. In an in-vitro model of experimental damage to podocytes, co-culture with INS-MSCs appeared to be protective.

DISCUSSION

Our results demonstrate that INS-MSCs maintain the main biological and functional properties typical of HD-MSCs; these data suggest that MSCs may be used in autologous cellular therapy approaches for INS treatment.

Liraglutide Reduces Both Atherosclerosis and Kidney Inflammation in Moderately Uremic LDLr-/- Mice

Chronic kidney disease (CKD) leads to uremia. CKD is characterized by a gradual increase in kidney fibrosis and loss of kidney function, which is associated with a progressive increase in risk of atherosclerosis and cardiovascular death. To prevent progression of both kidney fibrosis and atherosclerosis in uremic settings, insight into new treatment options with effects on both parameters is warranted. The GLP-1 analogue liraglutide improves glucose homeostasis, and is approved for treatment of type 2 diabetes. Animal studies suggest that GLP-1 also dampens inflammation and atherosclerosis. Our aim was to examine effects of liraglutide on kidney fibrosis and atherosclerosis in a mouse model of moderate uremia (5/6 nephrectomy (NX)). Uremic (n = 29) and sham-operated (n = 14) atherosclerosis-prone low density lipoprotein receptor knockout mice were treated with liraglutide (1000 μg/kg, s.c. once daily) or vehicle for 13 weeks. As expected, uremia increased aortic atherosclerosis. In the remnant kidneys from NX mice, flow cytometry revealed an increase in the number of monocyte-like cells (CD68⁺F4/80^-), CD4⁺, and CD8⁺ T-cells, suggesting that moderate uremia induced kidney inflammation. Furthermore, markers of fibrosis (i.e. Col1a1 and Col3a1) were upregulated, and histological examinations showed increased glomerular diameter in NX mice. Importantly, liraglutide treatment attenuated atherosclerosis (~40%, p < 0.05) and reduced kidney inflammation in NX mice. There was no effect of liraglutide on expression of fibrosis markers and/or kidney histology. This study suggests that liraglutide has beneficial effects in a mouse model of moderate uremia by reducing atherosclerosis and attenuating kidney inflammation.

Elevated levels of serum IL-12 and IL-18 are associated with lower frequencies of CD4(+)CD25 (high)FOXP3 (+) regulatory t cells in young patients with type 1 diabetes

Type 1 diabetes is thought to involve chronic inflammation, which is manifested by the activation and expression of different inflammatory mediators. IL-12 and IL-18 are two cytokines that have been shown to exert strong proinflammatory activity and have been implicated in the pathogenesis of type 1 diabetes in mice and humans. The overproduction of proinflammatory mediators is controlled by specialized T cell subset, namely regulatory T cells that express FOXP3 transcription factor. Since IL-12 and IL-18 mediate inflammatory response and Tregs exhibit anti-inflammatory potential, we aimed to examine their reciprocal relationship in patients with type 1 diabetes. The study group consisted of 47 children diagnosed with type 1 diabetes and 28 healthy individuals. Serum levels of IL-12 and IL-18 were measured by ELISA, and the peripheral blood CD4⁺CD25^high FOXP3⁺ regulatory T cell frequencies were analyzed by flow cytometry. Patients with type 1 diabetes had a decreased percentage of circulating CD4⁺CD25^highFOXP3⁺ Tregs in comparison to their healthy counterparts. In addition, they produced more IL-12 and IL-18 than children from the control group. Concentrations of these cytokines positively correlated with one another, as well as with CRP and HbA1c. Moreover, the negative association between IL-12, IL-18, CRP serum levels, and the frequency of regulatory CD4⁺CD25^highFOXP3⁺ Tregs was observed. IL-12 and IL-18 may have direct or indirect impact on regulatory T cell subset, which may contribute to their reduced frequency in peripheral blood of patients with type 1 diabetes mellitus.

Increased Migratory and Activation Cell Markers of Peripheral Blood Lymphocytes in an Experimental Model of Nephrotic Syndrome

The present study aimed to evaluate the expression of CD80 and CD18 in subpopulations of peripheral blood leukocytes and oxidative kidney damage in rats with nephrotic syndrome (NS) induced by doxorubicin (Dox) in comparison to control animals at different time points. Male adult Wistar rats were submitted to 24-hour urine and blood collection for biochemical and immunological analysis at 7, 14, 21, and 28 days after Dox injection. After euthanasia, the kidneys were removed for histological analysis and the evaluation of oxidative stress. The phenotypic characterization of leukocytes was performed using flow cytometry. Dox-injected animals exhibited increased CD18 expression in cytotoxic T lymphocytes, NK cells, and monocytes and high CD80 expression in monocytes. Kidney oxidative damage was positively correlated with CD80 expression in monocytes and serum levels of creatinine. These results suggest that phagocytic and cytotoxic cells are preferentially recruited to the tissue injury site, which may contribute to kidney dysfunction in this animal model of NS. The blockade of integrin and costimulatory molecules may provide new therapeutic opportunities for NS.

Role of Myeloid-Derived Suppressor Cells in Glucocorticoid-Mediated Amelioration of FSGS

The mechanism by which glucocorticoids alleviate renal inflammatory disorders remains incompletely understood. Here, we report that the efficacy of glucocorticoids in ameliorating FSGS depends on the capacity to expand myeloid-derived suppressor cells (MDSCs). After glucocorticoid treatment, the frequency of CD11b(+)HLA-DR(-)CD14(-)CD15(+) MDSCs in peripheral blood rapidly increased in patients with glucocorticoid-sensitive FSGS but remained unchanged in patients with glucocorticoid-resistant FSGS. The frequency of CD11b(+)Gr-1(+) MDSCs in mouse peripheral blood, bone marrow, spleen, kidney-draining lymph nodes (KDLNs), and kidney also increased after glucocorticoid treatment. The induced MDSCs from glucocorticoid-treated mice strongly suppressed T cells, dendritic cells, and macrophages but induced regulatory T cells in spleen, KDLNs, and kidney. Moreover, glucocorticoid treatment suppressed doxorubicin-induced T cell proliferation, dendritic cell and macrophage infiltration, and proinflammatory cytokine production, whereas this protective effect was largely abolished by depleting MDSCs using anti-Gr-1 antibody. Finally, the adoptive transfer of induced MDSCs into the doxorubicin-treated mice not only confirmed the protective role of MDSCs in doxorubicin-induced renal injury but also showed that the transferred MDSCs rapidly migrated into the lymphocyte-accumulating organs, such as the spleen and KDLNs, where they suppressed T cell proliferation. Taken together, these results demonstrate that glucocorticoid treatment ameliorates FSGS by expanding functional MDSCs and that this rapid elevation of MDSCs in peripheral blood may serve as an indicator for predicting the efficacy of glucocorticoid treatment.

The role of the immune system in idiopathic nephrotic syndrome: a review of clinical and experimental studies

Idiopathic nephrotic syndrome (INS) is a multifactorial disease, characterized by proteinuria, hypoalbuminemia, edema and hyperlipidemia. Studies in humans and animal models have associated INS with changes in the immune response. The purpose of this article is to review clinical and experimental findings showing the involvement of the immune response in the pathogenesis of INS. The role of the immune system in INS has been shown by clinical and experimental studies. However, the pattern of immune response in patients with INS is still not clearly defined. Many studies show changes in the dynamics of T lymphocytes, especially the regulatory T cells. Alternatively, there are other reports regarding the involvement of the complement system and B lymphocytes in the pathophysiology of INS. Indeed, none of the immunological biomarkers evaluated were undeniably linked to changes in glomerular permeability and proteinuria. On the other hand, some studies suggest a link between urinary chemokines, such as IL-8/CXCL8 and MCP-1/CCL2, and changes in glomerular permeability and/or the deterioration of glomerulopathies. To understand the pathophysiology of INS, longitudinal studies are clearly needed. The characterization of the profile of the immune response might help the development of specific and individualized therapies, leading to clinical improvement and better prognosis.

Citral is renoprotective for focal segmental glomerulosclerosis by inhibiting oxidative stress and apoptosis and activating Nrf2 pathway in mice

The pathogenesis of focal segmental glomerulosclerosis (FSGS) is considered to be associated with oxidative stress, mononuclear leukocyte recruitment and infiltration, and matrix production and/or matrix degradation, although the exact etiology and pathogenic pathways remain to be determined. Establishment of a pathogenesis-based therapeutic strategy for the disease is clinically warranted. Citral (3,7-dimethyl-2,6-octadienal), a major active compound in Litseacubeba, a traditional Chinese herbal medicine, can inhibit oxidant activity, macrophage and NF-κB activation. In the present study, first, we used a mouse model of FSGS with the features of glomerular epithelial hyperplasia lesions (EPHLs), a key histopathology index of progression of FSGS, peri-glomerular inflammation, and progressive glomerular hyalinosis/sclerosis. When treated with citral for 28 consecutive days at a daily dose of 200 mg/kg of body weight by gavage, the FSGS mice showed greatly reduced EPHLs, glomerular hyalinosis/sclerosis and peri-glomerular mononuclear leukocyte infiltration, suggesting that citral may be renoprotective for FSGS and act by inhibiting oxidative stress and apoptosis and early activating the Nrf2 pathway. Meanwhile, a macrophage model involved in anti-oxidative and anti-inflammatory activities was employed and confirmed the beneficial effects of citral on the FSGS model.

IgM contributes to glomerular injury in FSGS

Glomerular IgM and C3 deposits frequently accompany idiopathic FSGS and secondary glomerulosclerosis, but it is unknown whether IgM activates complement, possibly contributing to the pathogenesis of these diseases. We hypothesized that IgM natural antibody binds to neoepitopes exposed in the glomerulus after nonimmune insults, triggering activation of the complement system and further injury. We examined the effects of depleting B cells, using three different strategies, on adriamycin-induced glomerulosclerosis. First, we treated wild-type mice with an anti-murine CD20 antibody, which depletes B cells, before disease induction. Second, we evaluated adriamycin-induced glomerulosclerosis in Jh mice, a strain that lacks mature B cells. Third, we locally depleted peritoneal B cells via hypotonic shock before disease induction. All three strategies reduced deposition of IgM in the glomerulus after administration of adriamycin and attenuated the development of albuminuria. Furthermore, we found that glomerular IgM and C3 were detectable in a subset of patients with FSGS; C3 was present as an activation fragment and colocalized with glomerular IgM, suggesting that glomerular IgM may have bound a cognate ligand. Taken together, these results suggest that IgM activates the complement system within the glomerulus in an animal model of glomerulosclerosis. Strategies that reduce IgM natural antibody or that prevent complement activation may slow the progression of glomerulosclerosis.

Potential metabolomic biomarkers for evaluation of adriamycin efficacy using a urinary 1H-NMR spectroscopy

A metabolomics approach using proton nuclear magnetic resonance (NMR) was applied to investigate metabolic alterations following adriamycin (ADR) treatment for gastric adenocarcinoma. After BALB/c-nu/nu mice were implanted with human gastric adenocarcinoma, ADR (1 or 3 mg kg(-1) per day) was intraperitoneally administered for 5 days. Urine was collected on days 2 and 5 and analyzed by NMR. The levels of trimethylamine oxide (TMAO, ×0.3), hippurate (×0.3) and taurine (×0.6) decreased significantly (P < 0.05), whereas the levels of 3-indoxylsulfate (×12.6), trigonelline (×1.5), citrate (×2.5), trimethylamine (TMA, ×2.0) and 2-oxoglutarate (×2.3) increased significantly (P < 0.05) in the tumor model. After ADR treatment, TMAO, hippuarte and taurine were increased significantly on day 5 compared with those of the tumor model. The levels of 2-oxoglutarate, 3-indoxylsulfate, trigonelline, TMA and citrate, which increased in the tumor model, significantly decreased to those of normal control by ADR treatment. Furthermore, the ratio between TMA and TMAO was dramatically altered in both tumor and ADR-treated groups. Overall, metabolites such as TMAO, TMA, 3-indoxylsulfate, hippurate, trigonelline, citrate and 2-oxoglutarate related to the tricarboxylic acid (TCA) cycle might be considered as therapeutic targets to potentiate the efficacy of ADR. Thus, these results suggest that the metabolomics analysis of tumor response to ADR treatment may be applicable for demonstrating the efficacy of anticancer agent, ADR and treatment adaptation.

The polysaccharide fraction of Propionibacterium acnes modulates the development of experimental focal segmental glomerulosclerosis

The pathogenesis of focal segmental glomerulosclerosis (FSGS) appears to be associated with type-2 cytokines and podocyte dysfunction. In this study, we tested the hypothesis that immunization with the polysaccharide fraction of Propionibacterium acnes (PS), a pro-Th1 agonist, may subvert the type-2 profile and protect podocytes from adriamycin-induced glomerulosclerosis. Adriamycin injection resulted in albuminuria and increased serum creatinine in association with loss of glomerular podocin and podoplanin expression, which is consistent with podocyte dysfunction. Renal tissue analysis revealed the expression of transcripts for GATA3 and fibrogenic-related proteins, such as TGF-β, tissue inhibitor of metalloproteinase-1 (TIMP-1) and metalloproteinase 9 (MMP9). In association with the expression of fibrogenic transcripts, we observed peri-glomerular expression of α-smooth muscle actin (α-SMA), indicating epithelial-to-mesenchymal transition, and increased expression of proliferating cell nuclear antigen (PCNA) in tubular cells, suggesting intense proliferative activity. Previous immunization with PS inhibited albuminuria and serum creatinine in association with the preservation of podocyte proteins and inhibition of fibrogenic transcripts and the expression of α-SMA and PCNA proteins. Tissue analysis also revealed that PS treatment induced expression of mRNA for GD3 synthase, which is a glycosiltransferase related to the synthesis of GD3, a ganglioside associated with podocyte physiology. In addition, PS treatment inhibited the influx of inflammatory CD8(pos) and CD11b(pos) cells to kidney tissue. Finally, PS treatment on day 4 post-ADM, a period when proteinuria was already established, was able to improve renal function. Thus, we demonstrate that the PS fraction of P. acnes can inhibit FSGS pathogenesis, suggesting that immunomodulation can represent an alternative approach for disease management.

Renal disease in HIV infected patients at University of Benin Teaching Hospital in Nigeria

BACKGROUND

HIV related renal disease is a common occurrence in patients with HIV infection. It is the third leading cause of end stage renal disease among African-American males between the ages of 20 and 64 years in USA. Renal function impairment has been reported at all stages of HIV infection. The aim of this study is to determine the relationship between severity of renal function impairment and CD4 cell count in HIV infected patients.

METHOD

HIV patients presenting at University of Benin Teaching Hospital Benin, City Nigeria from 1(st) January to 30(th) June 2007 were randomly selected and screened for renal functional impairment (RFI). Those with RFI detected by glomerular filtration rate < 60 ml/min/1.73 m(2) or urine protein creatinine ratio 3 200 were stratified into mild, moderate and severe RFI. Forty patients from each stratum and forty HIV infected patients with normal renal functions were recruited as subjects and control respectively. Their clinical and laboratory parameters were evaluated. The data obtained were analysed using SPSS vs 15.0.

RESULTS

Of the HIV patients screened, 53.3% had renal functional impairment. of these, 40.2% had mild, 37.7% had moderate and 22.2% had severe impairment in their renal functions respectively Their mean age was 36.0 ± 8.8 years. The CD4 cell count was found to be 309.75 ± 268.71/ul, 188.45 ± 173.12/ul, and 141.10 ± 126.01/ul among subjects with mild, moderate and severe RFI respectively. The CD4 cell count in control group was 319.05 ± 248.41/ul. The difference was statistically significant. (p = <0.001). CD4 cell count had a significant positive correlation with GFR (r = 0.32, p = 0.042). However, there was a negative correlation between CD4 cell count and proteinuria but this was not statistically significant (r = 0.09, p = 0.173).

CONCLUSION

Severity of RFI has a positive correlation with degree of immunosuppression in HIV infected patients.

Aristolochic acid nephropathy revisited: a place for innate and adaptive immunity?

AIMS

The histological features of aristolochic acid nephropathy (AAN) consist of paucicellular interstitial fibrosis, severe tubular atrophy, and almost intact glomeruli with media lesions of interlobular arteries. As an early phase of interstitial inflammation preceded peritubular fibrosis in the rat model of AAN, the aim was to investigate the presence of inflammatory cells in human AAN.

METHODS AND RESULTS

Reports of confirmed cases and case series of AAN were reviewed in terms of interstitial inflammation and found to have very conflicting results. This prompted us to search for and characterize inflammatory cells within the native kidneys provided from four end-stage AAN patients. Prior aristolochic acid exposure was attested by the intrarenal presence of the typical aristolactam I-derived DNA adduct. Besides the tubulointerstitial lesions usually seen in the cortex, a massive infiltration of macrophages, T and B lymphocytes was detected by immunohistochemistry in the medullary rays and in the outer medullae with some extension to the upper cortical labyrinth.

CONCLUSIONS

In parallel with histological findings reported in the rat model, inflammatory cells are present preferentially in the interstitium of the medullary rays and of the outer medulllae in renal interstitium from human AAN cases, even in the terminal stages. Further studies must be undertaken to determine the respective roles of innate and adaptive immunity in the progression of AAN.

IL-10/TGF-beta-modified macrophages induce regulatory T cells and protect against adriamycin nephrosis

IL-10/TGF-beta-modified macrophages, a subset of activated macrophages, produce anti-inflammatory cytokines, suggesting that they may protect against inflammation-mediated injury. Here, macrophages modified ex vivo by IL-10/TGF-beta (IL-10/TGF-beta Mu2) significantly attenuated renal inflammation, structural injury, and functional decline in murine adriamycin nephrosis (AN). These cells deactivated effector macrophages and inhibited CD4+ T cell proliferation. IL-10/TGF-beta Mu2 expressed high levels of the regulatory co-stimulatory molecule B7-H4, induced regulatory T cells from CD4+CD25- T cells in vitro, and increased the number of regulatory T cells in lymph nodes draining the kidneys in AN. The phenotype of IL-10/TGF-beta Mu2 did not switch to that of effector macrophages in the inflamed kidney, and these cells did not promote fibrosis. Taken together, these data demonstrate that IL-10/TGF-beta-modified macrophages effectively protect against renal injury in AN and may become part of a therapeutic strategy for chronic inflammatory disease.

Inducible rodent models of acquired podocyte diseases

Glomerular diseases remain the leading cause of chronic and end-stage kidney disease. Significant advances in our understanding of human glomerular diseases have been enabled by the development and better characterization of animal models. Diseases of the glomerular epithelial cells (podocytes) account for the majority of proteinuric diseases. Rodents have been extensively used experimentally to better define mechanisms of disease induction and progression, as well as to identify potential targets and therapies. The development of podocyte-specific genetically modified mice has energized the research field to better understand which animal models are appropriate to study acquired podocyte diseases. In this review we discuss inducible experimental models of acquired nondiabetic podocyte diseases in rodents, namely, passive Heymann nephritis, puromycin aminonucleoside nephrosis, adriamycin nephrosis, liopolysaccharide, crescentic glomerulonephritis, and protein overload nephropathy models. Details are given on the model backgrounds, how to induce each model, the interpretations of the data, and the benefits and shortcomings of each. Genetic rodent models of podocyte injury are excluded.

Regulatory immune cells in kidney disease

Lymphocytes and macrophages act as effector immune cells in the initiation and progression of renal injury. Recent data have shown that subpopulations of these immune cells (regulatory T lymphocytes and alternately-activated or regulatory macrophages) are potent modulators of tissue injury and repair in renal disease. Recent animal studies examining the therapeutic effect of these cells raise the exciting possibility that strategies targeting these cell types may be effective in treating and preventing kidney disease in humans. This review will describe their biological role in experimental kidney disease and therapeutic potential in clinical nephrology.

RAGE mediates podocyte injury in adriamycin-induced glomerulosclerosis

In the kidney, the receptor for advanced glycation end products (RAGE) is principally expressed in the podocyte at low levels, but is upregulated in both human and mouse glomerular diseases. Because podocyte injury is central to proteinuric states, such as the nephrotic syndrome, the murine adriamycin nephrosis model was used to explore the role of RAGE in podocyte damage. In this model, administration of the anthracycline antibiotic adriamycin provokes severe podocyte stress and glomerulosclerosis. In contrast to wild-type animals, adriamycin-treated RAGE-null mice were significantly protected from effacement of the podocyte foot processes, albuminuria, and glomerulosclerosis. Administration of adriamycin induced rapid generation of RAGE ligands, and treatment with soluble RAGE protected against podocyte injury and glomerulosclerosis. In vitro, incubation of RAGE-expressing murine podocytes with adriamycin stimulated AGE formation, and treatment with RAGE ligands rapidly activated nicotinamide adenine dinucleotide phosphate (NADPH)-oxidase, via p44/p42 MAP kinase signaling, and upregulated pro-fibrotic growth factors. These data suggest that RAGE may contribute to the pathogenesis of podocyte injury in sclerosing glomerulopathies such as focal segmental glomerulosclerosis.

Depletion of gammadelta T cells exacerbates murine adriamycin nephropathy

It has been reported that the presence of gammadelta T cells in kidney is associated with kidney damage in human IgA nephropathy and in rat models of chronic renal injury, including Adriamycin nephropathy (AN), but the functional role of gammadelta T cells in this setting is unknown. This study examined the functional role of gammadelta T cells in tissue injury in a murine model of AN. Murine AN was induced in BALB/c mice by a single injection of Adriamycin. gammadelta T cells as a proportion of CD3(+) T cells were significantly increased in AN kidneys (16.8 +/- 3.9%) but not in lymph nodes (1.3 +/- 0.8%; P < 0.001). The proportion of gammadelta T cells in AN kidney correlated positively with serum creatinine and glomerular sclerosis. The Vgammadelta T cell receptor (TCR) repertoire in kidney showed expansion of a subset of cells that expressed Vgamma6/Vdelta1 genes and that used canonical TCR Vgamma6/Vdelta1 sequences in the CDR3 region of the TCR. gammadelta T cells that were sorted from the kidneys expressed TGF-beta but not IL-4, IL-10, or IFN-gamma. gammadelta T cells also expressed the activating receptor NKG2D and the NKG2D adaptor molecule DAP12. RAE-1, a ligand of NKG2D, was upregulated in AN kidney. Depletion of gammadelta T cells using anti-TCR gammadelta antibody resulted in worsening of serum creatinine, glomerulosclerosis, and interstitial inflammation. These studies indicate the involvement of the gammadelta T cell in innate recognition and regulation of inflammation in AN.

CD4+CD25+Regulatory T Cells Protect against Injury in an Innate Murine Model of Chronic Kidney Disease

Studies of mechanisms of disease regulation by CD4+CD25+ regulatory T cells (Treg) have been focused on their interaction with effector T cells; however, the possibility that regulation might involve noncognate cells has not been explored in detail. This study investigated the effect of CD4+CD25+ Treg on macrophage proinflammatory properties and phenotype in vitro and found that they modulate macrophages by inhibiting their activation, leading to reduced proinflammatory cytokine production and a downregulated effector phenotype. For testing the in vivo significance of this effect, CD4+CD25+ T cells that expressed high levels of Foxp3 were reconstituted into SCID mice after induction of Adriamycin nephropathy, a noncognate model of chronic renal disease. CD4+CD25+ T cells significantly reduced glomerular and interstitial injury. In addition, there was a significant fall in the number of macrophages in both the glomeruli and interstitium of SCID mice that were reconstituted with Treg as compared with the Adriamycin alone group. Blockade of TGF-beta using neutralizing antibodies significantly impaired the protective effect of Treg. These findings delineate a TGF-beta-dependent Treg-macrophage inhibitory interaction that can explain cognate-independent protection by Treg.

NK cells do not mediate renal injury in murine adriamycin nephropathy

In adriamycin nephropathy (AN), a model of chronic proteinuric renal injury, the absence of functional B and T cells with residual natural killer (NK) cells, and macrophages in severe combined immunodeficient (SCID) mice results in more severe disease than in immunocompetent mice. We have recently shown expression of the stimulatory NK cell molecule NKG2D and its ligand RAE-1 in the adriamycin (ADR) kidney. Therefore, we sought to determine the role of NK cells in AN. We used anti-asialo GM1 NK cell depletion in immunocompetent BALB/c mice with AN, and also compared AN in immunodeficient SCID mice and immunodeficient nonobese diabetic (NOD)-SCID mice (that have impaired NK cell function). The number of NK cells was increased in AN in BALB/c mice compared with normal controls. NK cell depletion or reduction of NK function in NOD-SCID mice did not affect the severity of disease. In both wild type and immunodeficient models, ADR upregulated RAE-1 in the kidney. High levels of Class I major histocompatibility complex molecules were found in both models of AN. In conclusion, NK cells do not play a significant role in AN.

A Pathophysiologic Role for T Lymphocytes in Murine Acute Cisplatin Nephrotoxicity

Recent evidence supports a role for an inflammatory pathogenesis of cisplatin nephrotoxicity, but immune cell-mediated mechanisms in this disease are still largely unknown. The role for T lymphocytes on cisplatin-induced acute kidney injury was examined with C57BL/6 T cell-deficient (nu/nu) mice and CD4- or CD8-deficient mice and their wild-type (WT) littermates. All mice received a single dose of cisplatin at 40 mg/kg (intraperitoneally) and were followed up for 72 h. At 72 h after cisplatin administration, T cell-deficient mice had a marked attenuation in renal dysfunction (serum creatinine 3.2+/-0.5 versus 0.8+/-0.1 mg/dl; P=0.007), kidney tubular injury (scores 1.44+/-0.15 versus 0.22+/-0.08; P<0.0001), and survival. Adoptive transfer of T cells into nu/nu mice followed by cisplatin enhanced renal dysfunction and tubular injury. The increase in renal myeloperoxidase activity after cisplatin administration was blunted in nu/nu mice. Renal TNF-alpha, IL-1beta, and keratinocyte-derived chemokine protein expression was increased in WT mice but not in nu/nu mice after cisplatin administration. T cell levels significantly increased in kidneys of WT mice after cisplatin administration as early as at 1 h, peaked at 12 h, and declined by 24 h. CD4- and, to a lesser degree, CD8-deficient mice were relatively protected from cisplatin-induced mortality and renal dysfunction compared with WT mice. These data demonstrate that T lymphocytes are direct mediators of experimental cisplatin nephrotoxicity. Targeting T lymphocytes could lead to improved ways to administer cisplatin safely to cancer patients.

Foxp3-transduced polyclonal regulatory T cells protect against chronic renal injury from adriamycin

Chronic proteinuric renal injury is a major cause of ESRD. Adriamycin nephropathy is a murine model of chronic proteinuric renal disease whereby chemical injury is followed by immune and structural changes that mimic human disease. Foxp3 is a gene that induces a regulatory T cell (Treg) phenotype. It was hypothesized that Foxp3-transduced Treg could protect against renal injury in Adriamycin nephropathy. CD4+ T cells were transduced with either a Foxp3-containing retrovirus or a control retrovirus. Foxp3-transduced T cells had a regulatory phenotype by functional and phenotypic assays. Adoptive transfer of Foxp3-transduced T cells protected against renal injury. Urinary protein excretion and serum creatinine were reduced (P<0.05), and there was significantly less glomerulosclerosis, tubular damage, and interstitial infiltrates (P<0.01). It is concluded that Foxp3-transduced Treg cells may have a therapeutic role in protecting against immune injury and disease progression in chronic proteinuric renal disease.

DNA vaccination with CCL2 DNA modified by the addition of an adjuvant epitope protects against "nonimmune" toxic renal injury

CC-chemokine-encoding DNA vaccine has been reported to be capable of inducing immunologic memory to corresponding pathogenic self CC-chemokines in animal models of autoimmune disease. This study investigated whether introduction of a foreign T helper epitope into monocyte chemoattractant protein 1 (CCL2) DNA vaccine could boost its immunogenicity by inducing strong neutralizing autoantibody against the pathogenic chemokine CCL2 sufficiently to be protective in a classically nonimmune model of disease, Adriamycin nephropathy (AN). Modification of the CCL2 DNA vaccine by replacing a surface loop region of CCL2 sequence with tetanus toxoid T helper epitope P30 elicited a strong self-specific CCL2 autoantibody production, as well as an IFN-gamma-producing T cell cellular response. The increased immunogenicity of modified CCL2 DNA vaccination but not unmodified CCL2 DNA vaccination was protective against functional and structural renal injury in rat AN. The protective effect of the modified CCL2 DNA vaccine was associated with blockade of glomerular and interstitial macrophage recruitment by neutralizing autoantibody against CCL2, which plays a critical role in eliciting renal injury in AN. Therefore, modification with a foreign T helper epitope breaks self-tolerance by inducing a cellular and humoral response against self-protein and provides a strategy to increase the potency of DNA vaccination sufficiently to afford protection in toxin-induced chronic renal disease.

Macrophages and progressive tubulointerstitial disease

Macrophages and progressive tubulointerstitial disease. In chronic renal disease, tubulointerstitial inflammation and injury is associated with infiltrating macrophages. As a consequence of primary injury, proteinuria, chronic hypoxia, and glomerular-derived cytokines may all differentially modulate the expression of factors that promote macrophage recruitment. In addition to adhesion molecules and chemokines, products of complement system and renin-angiotensin system activation may direct this process. Once present at interstitial sites, macrophages interact with resident cells and extracellular matrix to generate a proinflammatory microenvironment that amplifies tissues injury and promotes scarring. There is now increasing evidence for the efficacy of interventions directed against factors that recruit, activate, or are produced by macrophages. A detailed understanding of the biology of this area may lead to the further development of therapies that will improve the outcome of renal disease.

DNA vaccination with naked DNA encoding MCP-1 and RANTES protects against renal injury in adriamycin nephropathy

BACKGROUND

We have previously shown that monocyte chemoattractant protein-1 (MCP-1) and regulated upon activation, normal T-cell expressed and secreted (RANTES) are significantly increased in renal cortex in adriamycin nephropathy. In this study, we tested the effect of DNA vaccination encoding the C-C chemokines MCP-1 and RANTES in a rat model of adriamycin nephropathy.

METHODS

Both reverse transcription-polymerase chain reaction (RT-PCR) products of MCP-1 and RANTES used as constructs were cloned into a pTarget vector for naked DNA vaccination. Two hundred micrograms of DNA was injected into the tibialis anterior muscle four times at weekly intervals. One week after the last DNA vaccination, rats received adriamycin. All animals were sacrificed 4 weeks after adriamycin administration. Changes in renal function and histologic features were assessed. Enzyme-linked immunosorbent assay (ELISA) and Western blot were used for autoantibody determination. Antibody specificity was assessed in in vitro transmigration assays.

RESULTS

Chemokine DNA vaccination significantly reduced proteinuria (P < 0.05) and ameliorated creatinine clearance (P < 0.05) at 2, 3, and 4 weeks after adriamycin administration. Morphometric analysis showed less glomerular sclerosis (P < 0.001) and interstitial infiltrates (P < 0.005) in chemokine DNA vaccination group compared with control groups. Anti-MCP-1 and RANTES autoantibodies were detected in higher concentrations in chemokine DNA vaccinated rats than in control rats (P < 0.001) and serum from vaccinated rats blocked T-cell transmigration to MCP-1 and RANTES.

CONCLUSION

In this study, we have shown that naked DNA vaccination against MCP-1 and RANTES ameliorates the progression of renal disease in the rat adriamycin nephropathy model of chronic proteinuric renal disease. The protective mechanism may involve the production of autoantibodies against MCP-1 and RANTES.

The role of tubulointerstitial inflammation

BACKGROUND

Exploration of the role of tubulointerstitial inflammation in experimental chronic renal disease (CRD) is an essential step to understanding and finding new treatments for human CRD. Adriamycin nephrosis (AN) is an experimental analogue of human focal glomerular sclerosis and tubulointerstitial inflammation.

METHODS

Using murine and rat AN, we have systematically investigated the pathogenic roles of chemokines, costimulatory molecules, and inflammatory cells, such as macrophages and effector and regulatory T lymphocytes. The profile of humoral and cellular mediators was studied in vitro and in vivo. The pathogenic significance of various factors was investigated by DNA vaccination, leukocyte reconstitution and depletion, retroviral transduction, and blockade with monoclonal antibodies.

RESULTS

Renal cortical and tubular cell CC-chemokines, including MCP-1, RANTES, and MIP-1alpha, were up-regulated via mediation of NFkappaB, and contributed to disease by attracting inflammatory cells into the interstitium. The role of these chemokines was confirmed by DNA vaccination. CD40-CD40L costimulation signals were involved in expansion and activation of the inflammatory infiltrate, whereas PD-1 signals were inhibitory, and CD28-B7 appeared to have a neutral effect. Macrophage and CD8+ T cells were shown to be effectors of injury, whereas CD4+CD25+ and gammadelta T cells acted as regulatory cells. FoxP3 transduction was able to convert naive T cells to CD4+CD25+ regulatory T cells.

CONCLUSION

There is a broad range of humoral and cellular factors involved in the pathogenesis of experimental CRD, some of which are potential targets for treatment of human CRD.

Epithelial sodium channel, salt intake, and hypertension

The epithelial sodium channel (ENaC) is a membrane protein made of three different but homologous subunits (a, b, and g) present in the apical membrane of epithelial cells of, for example, the distal nephron. This channel is responsible for salt reabsorption in the kidney and can cause human diseases by increasing channel function in Liddle's syndrome, a form of hereditary hypertension, or by decreasing channel function in pseudohypoaldosteronism type I, a salt-wasting disease in infancy. This review briefly discusses recent advances in understanding the implication of ENaC in Liddle's syndrome and in pseudohypoaldosteronism type I, both caused by mutations in the SCNN1 (ENaC) genes. Furthermore, it is still an open question to which extent SCNN1 genes coding for ENaC might be implicated in essential hypertension. The development of Scnn1 genetically engineered mouse models will provide the opportunity to test the effect of environmental factors, like salt intake, on the development of this kind of salt- sensitive hypertension.