The effects of anti-inflammatory and anti-angiogenic DNA vaccination on diabetic nephropathy in rats

Immunological Approaches in the Treatment of Diabetic Nephropathy

Diabetic nephropathy (DN), the leading cause of end-stage renal disease, has no definite treatment so far. In fact, a combination of metabolic, hemodynamic, and immunological factors are involved in the pathogenesis of DN; therefore, effective disease management requires a holistic approach to all predisposing contributors. Due to the recent findings about the role of inflammation in the initiation and progression of kidney injury in diabetic patients and considerable advances in immunotherapy methods, it might be useful to revise and reconsider the current knowledge of the potential of immunomodulation in preventing and attenuating DN. In this review, we have summarized the findings of add-on therapeutic methods that have concentrated on regulating inflammatory responses in diabetic nephropathy, including phosphodiesterase inhibitors, nuclear factor-kB inhibitors, Janus kinase inhibitors, chemokine inhibitors, anti-cytokine antibodies, cell therapy, and vaccination.

Identification of Multiple Hub Genes in Acute Kidney Injury after Kidney Transplantation by Bioinformatics Analysis

Background and Objectives: The molecular mechanisms of the development of acute kidney injury (AKI) after kidney transplantation are not yet clear. The aim of this study was to confirm the genes and mechanisms related to AKI after transplantation. Materials and Methods: To investigate potential genetic targets for AKI, an analysis of the gene expression omnibus database was used to identify key genes and pathways. After identification of differentially expressed genes, Kyoto Encyclopedia of Genes and Genome pathway enrichment analyses were performed. We identified the hub genes and established the protein-protein interaction network. Results: Finally, we identified 137 differentially expressed genes (59 upregulated genes and 16 downregulated genes). AKAP12, AMOT, C3AR1, LY96, PIK3AP1, PLCD4, PLCG2, TENM2, TLR2, and TSPAN5 were filtrated by the hub genes related to the development of post-transplant AKI from the Protein-Protein Interaction (PPI) network. Conclusions: This may provide important evidence of the diagnostic and therapeutic biomarker of AKI.

Therapeutic DNA vaccine encoding CEMIP (KIAA1199) ameliorates kidney fibrosis in obesity through inhibiting the Wnt/β-catenin pathway

BACKGROUND

CEMIP is a novel risk factor of various cancers through activating Wnt/β-catenin /epithelial-mesenchymal transition between epithelial cells and stroma. The chronic fibrosis commonly contributes renal carcinogenesis in patients with obesity. As there have very few choices of medicines targeting CEMIP. This study intended to design therapeutic DNA vaccines for nephropathy in obesity, through diminishing the CEMIP/Wnt1/β-catenin pathway.

METHOD

In an 8-week experiment, plasmid-encoding CEMIP was vaccinated into high-fat diet (HFD) or obesity mice in the first 4 weeks, and then vaccination was stopped for at least 4 weeks. Then, plasma and spleens were harvested to evaluate anti-CEMIP antibody synthesis and T-helper type 1 and 2 activation after vaccination. Kidneys were collected to investigate efficacy of CEMIP DNA vaccine on inhibiting HFD and obesity-induced fibrosis and Wnt1/β-catenin pathway. To confirm that CEMIP crucially contributed towards fibrotic formation, CEMIP gene or siRNA transfection was performed in HK-2 cells under VLDL stimulation, or not.

RESULTS

At the end point, anti-CEMIP antibody was successfully produced in the pcDNA 3.1-CEMIP vaccinated group, while Wnt1/β-catenin signaling and fibrosis was inactive. Through VLDL stimulation and CEMIP overexpression, Wnt1/β-catenin signaling and fibrosis significantly presented in vitro. Otherwise, anti-sera of CEMIP-vaccinated mice could inhibit the VLDL-induced Wnt1/β-catenin/fibrosis pathway in HK-2 cells. Similarly, the silencing of CEMIP by siRNA ameliorated the Wnt1/β-catenin pathway and fibrogenesis under VLDL stimulation.

CONCLUSION

DNA vaccine targeting CEMIP/Wnt1/β-catenin pathway plays a novel strategy in nephropathy.

GENERAL SIGNIFICANCE

Immune therapy might provide a new therapeutic option on nephropathy of obesity.

The future of diabetic kidney disease management: what to expect from the experimental studies?

Diabetic kidney disease (DKD) is a major cause of end-stage renal disease. Intensive blood glucose and blood pressure control, particularly using inhibitors of the renin-angiotensin system, have long been mainstays of therapy in patients with DKD. Moreover, new anti-hyperglycemic drugs have recently shown renoprotective effects and this represents a major progress in the management of DKD. However, the risk of progression is still substantial and additional drugs are required. Recent preclinical studies have identified novel therapeutic targets that may optimize renoprotection in the near future. Besides strategies aimed to reduce oxidative stress and inflammation in the kidney, novel extra-renal approaches targeting stem cells, extracellular vesicles, and the microbiota are on the horizon with promising preclinical data. Herein, we will review these lines of research and discuss potential clinical applications. Given the poor yield of experimental studies in DKD in the past years, we will also discuss strategies to improve translation of preclinical research to humans.

Behavioral Changes During Development of Chronic Kidney Disease in Rats

Decreased renal function due to chronic kidney disease (CKD) is associated with anxiety and cognitive decline. Although these mental disorders are often obvious in late stage renal disease patients, they might be unnoticeable or are neglected in early stages of the CKD development. Associations between renal and cognitive dysfunction have been indicated by studies performed mainly in patients undergoing dialysis, which itself represents a stress and decreased quality of life. However, experimental and causal studies are scarce. Our aim was to investigate dynamic changes in behavioral traits during the progression of CKD in an animal model. Thirty 12-week old male rats were used in this experiment. CKD was induced by a subtotal (5/6) nephrectomy. Two, 4, and 6 months after surgical induction of CKD, the open field, the light-dark box and the novel object recognition tests were conducted to assess the locomotor activity, anxiety-like behavior and the memory function of rats. Blood urea nitrogen (BUN), plasma concentration of creatinine (CREAT), albumin to creatinine ratio in urine (ACR) along with the renal histology were assessed to monitor the development and severity of CKD. In comparison to control rats, 5/6 nephrectomized rats had by 46–66% higher concentration of BUN during the whole follow-up period, as well as by 52% and by 167% higher CREAT and ACR, respectively, 6 months after surgery. Although the effect of time was observed in some behavioral parameters, nephrectomy did not significantly influence either locomotor activity, or anxiety-like behavior, or memory function of animals. Two and 4 months after surgery, animals moved shorter distance and spent less time in the center zone. However, the open-field ambulation returned back to the baseline level 6 months after CKD induction. Although nephrectomized rats displayed impaired kidney function as early as 2 months after surgery, no significant differences were found between the CKD and the control rats in any of the observed behaviors. Further studies are needed in order to evaluate whether behavioral abnormalities are related to severity of CKD or might be attributed to psychosocial aspect of end-stage renal disease and decreased quality of life in dialysis patients.

The effects of sucrose on urine collection in metabolic cages

Representative urine collection that respects the standards of animal welfare is still an issue in experimental nephrology. The commonly used metabolic cages induce stress in rodents. In mice, the volume of collected urine is sometimes insufficient for further analysis. The aim of this experiment was to analyse the effects of time of day, temperature and 2%, 5% or 10% sucrose solutions on diuresis, weight change and liquid intake of adult mice placed in metabolic cages for urine collection. Mice were placed in metabolic cages for 12 h during the day or night at standard ambient (22℃) and thermoneutral (28℃) temperatures. To determine the effect of acclimatisation, mice were placed in metabolic cages for five consecutive days. Diuresis increased with concentrations of sucrose. Body weight reduction was most rapid in the group given tap water and decreased with increasing sucrose concentrations. A drastic drop in body weight was observed in mice placed in metabolic cages for four consecutive days with access to tap water and food, indicating that time spent in metabolic cages should be kept to a minimum, as prolonged confinement in metabolic cages can be harmful to mice. The administration of concentrated sucrose solutions can potentially aid in mouse urine collection by reducing the time spent in metabolic cages. Sucrose supplementation increased the albumin/creatinine ratio. However, without showing estimates of glomerular filtration rate, renal haemodynamics, plasma electrolytes and urinary electrolyte excretions, the results of this study do not provide any conclusion about the effect of sucrose on renal function.

The physiological role of Motin family and its dysregulation in tumorigenesis

Members in Motin family, or Angiomotins (AMOTs), are adaptor proteins that localize in the membranous, cytoplasmic or nuclear fraction in a cell context-dependent manner. They control the bioprocesses such as migration, tight junction formation, cell polarity, and angiogenesis. Emerging evidences have demonstrated that AMOTs participate in cancer initiation and progression. Many of the previous studies have focused on the involvement of AMOTs in Hippo-YAP1 pathway. However, it has been controversial for years that AMOTs serve as either positive or negative growth regulators in different cancer types because of the various cellular origins. The molecular mechanisms of these opposite roles of AMOTs remain elusive. This review comprehensively summarized how AMOTs function physiologically and how their dysregulation promotes or inhibits tumorigenesis. Better understanding the functional roles of AMOTs in cancers may lead to an improvement of clinical interventions as well as development of novel therapeutic strategies for cancer patients.

The effects of anthocyanin-rich wheat diet on the oxidative status and behavior of rats

Aim

To evaluate the effect of food containing anthocyanin-rich wheat on oxidative status and behavior of healthy rats.

Methods

Twenty male rats were divided into the control and anthocyanin group. Oral glucose tolerance test was performed, and proteinuria and creatinine clearance were measured. Behavioral analysis was performed in Phenotyper cages. Serum and tissues were collected to measure the markers of oxidative stress and antioxidant status.

Results

Anthocyanins significantly increased total antioxidant capacity in serum (P = 0.039), decreased advanced oxidation protein products in the kidney (P = 0.002), but increased thiobarbituric acid reactive substances in the kidney compared to the control group. No significant difference between the groups was found in the markers of oxidative stress in the liver and colon, as well as in renal functions and glucose metabolism. The anthocyanin group spent significantly less time in the spotlight zone of the Phenotyper cages (P = 0.040), indicating higher anxiety-like behavior.

Conclusion

Food containing anthocyanin-rich wheat had positive effects on serum antioxidant status and kidney protein oxidation, but increased lipid peroxidation in the kidney and modified animal behavior related to anxiety. The molecular mechanisms leading to observed effects should be further elucidated.

Inflammation in diabetic nephropathy: moving toward clinical biomarkers and targets for treatment

Diabetic nephropathy (DN) is a leading cause of end stage renal failure and there is an urgent need to identify new clinical biomarkers and targets for treatment to effectively prevent and slow the progression of the complication. Many lines of evidence show that inflammation is a cardinal pathogenetic mechanism in DN. Studies in animal models of experimental diabetes have demonstrated that there is a low-grade inflammation in the diabetic kidney. Both pharmacological and genetic strategies targeting inflammatory molecules have been shown to be beneficial in experimental DN. In vitro studies have cast light on the cellular mechanisms whereby diabetes triggers inflammation and in turn inflammation magnifies the kidney injury. Translation of this basic science knowledge into potential practical clinical applications is matter of great interest for researchers today. This review focuses on key pro-inflammatory systems implicated in the development of DN: the tumor necrosis factor(TNF)-α/TNF-α receptor system, the monocyte chemoattractant protein-1/CC-chemokine receptor-2 system, and the Endocannabinoid system that have been selected as they appear particularly promising for future clinical applications.

Meta-analysis of diabetic nephropathy associated genetic variants in inflammation and angiogenesis involved in different biochemical pathways

Background

Diabetes mellitus is the most common chronic endocrine disorder, affecting an estimated population of 382 million people worldwide. It is associated with microvascular and macrovascular complications, including diabetic nephropathy (DN); primary cause of end-stage renal disease. Different inflammatory and angiogenic molecules in various pathways are important modulators in the pathogenesis and progression of diabetic nephropathy. Differential disease risk in DN may be partly attributable to genetic susceptibility. In this meta-analysis, we aimed to determine which of the previously investigated genetic variants in these pathways are significantly associated with the development of DN and to examine the functional role of these genes.

Methods

A systematic search was conducted to collect and analyze all studies published till June 2013; that investigated the association between genetic variants involved in inflammatory cytokines and angiogenesis and diabetic nephropathy. Genetic variants associated with DN were selected and analyzed by using Comprehensive Meta Analysis software. Pathway analysis of the genes with variants showing significant positive association with DN was performed using Genomatix Genome Analyzer (Genomatix, Munich, Germany).

Results

After the inclusion and exclusion criteria for this analysis, 34 studies were included in this meta-analysis. 11 genetic variants showed significant positive association with DN in a random-effects meta-analysis. These included genetic variants within or near VEGFA, CCR5, CCL2, IL-1, MMP9, EPO, IL-8, ADIPOQ and IL-10. rs1800871 (T) genetic variant in IL-10 showed protective effect for DN. Most of these eleven genetic variants were involved in GPCR signaling and receptor binding pathways whereas four were involved in chronic kidney failure. rs833061 [OR 2.08 (95% CI 1.63-2.66)] in the VEGFA gene and rs3917887 [OR 2.04 (95% CI 1.64-2.54)] in the CCL2 gene showed the most significant association with the risk of diabetic nephropathy.

Conclusions

Our results indicate that 11 genetic variants within or near VEGFA, CCR5, CCL2, IL-1, MMP9, EPO, IL-8, ADIPOQ and IL-10 showed significant positive association with diabetic nephropathy. Gene Ontology or pathway analysis showed that these genes may contribute to the pathophysiology of DN. The functional relevance of the variants and their pathways can lead to increased biological insights and development of new therapeutic targets.

Electronic supplementary material

The online version of this article (doi:10.1186/s12881-014-0103-8) contains supplementary material, which is available to authorized users.

Understanding regulatory pathways of neovascularization in diabetes

Diabetes mellitus and its associated comorbidities represent a significant health burden worldwide. Vascular dysfunction is the major contributory factor in the development of these comorbidities, which include impaired wound healing, cardiovascular disease and proliferative diabetic retinopathy. While the etiology of abnormal neovascularization in diabetes is complex and paradoxical, the dysregulation of the varied processes contributing to the vascular response are due in large part to the effects of hyperglycemia. In this review, we explore the mechanisms by which hyperglycemia disrupts chemokine expression and function, including the critical hypoxia inducible factor-1 axis. We place particular emphasis on the therapeutic potential of strategies addressing these pathways; as such targeted approaches may one day help alleviate the healthcare burden of diabetic sequelae.