Models Of Diabetic Kidney Disease Research Articles

FTO mediates the diabetic kidney disease progression through regulating the m6A modification of NLRP3

BackgroundThe objective of our research was to investigate the specific mechanism of FTO in diabetic kidney disease (DKD) progression.MethodsThe DKD model was established with renal tubular epithelial HK-2 cells and mice in vitro and in vivo. The N6-methyladenosine (m6A) content in cells was detected using dot plot assay and the m6A levels of NLRP3 was detected with the MeRIP assay. The mRNA and protein levels were tested with real-time reverse transcriptase-polymerase chain reaction (RT-qPCR) and western blot. The IL-1β and IL-18 levels were assessed with enzyme-linked immunosorbent assay (ELISA). The cell viability was measured by cell counting kit (CCK)-8 assay and cell pyroptosis was determined with Annexin V and propidium iodide (PI) double staining followed by flow cytometry analysis. RNA-binding protein immunoprecipitation (RIP) and dual luciferase reporter assays were conducted to detect the interaction between FTO and NLRP3. m6A levels were detected by Me-RIP assay. The renal injury was measured by observing the renal morphology and urine and blood levels of relevant indicators.ResultsThe results indicated that high glucose treatment induced HK-2 cell pyroptosis. m6A levels were prominently elevated in high glucose treated HK-2 cells while FTO expression were significantly down-regulated. FTO over-expression promoted cell viability but inhibited pyroptosis of HK-2 cells under high glucose (HG) treatment. Moreover, FTO could inhibit NLRP3 expression. RIP and Me-RIP assays indicated that FTO could bind with NLRP3 and regulate its m6A modification level. Further luciferase assay confirmed that FTO binds with the 233–237 bp region of NLRP3. NLRP3 neutralized the function of FTO in the HG stimulated HK-2 cells. In vivo, the H&E staining showed that FTO over-expression alleviated the kidney injury and suppressed the pyroptosis induced by DKD.ConclusionWe found that FTO could inhibit the DKD progression in vivo and in vitro by regulated the m6A modification of NLRP3.

Associations between Renin-Angiotensin System and Abnormal Renal Energy Metabolism in a Mouse Model of Diabetic Kidney Disease

Associations between Renin-Angiotensin System and Abnormal Renal Energy Metabolism in a Mouse Model of Diabetic Kidney Disease

Modulation of Kidney Disorders in Type 2 Diabetes: Evaluating the Role of Probiotics in a Rat Model of Diabetic Kidney Disease

Modulation of Kidney Disorders in Type 2 Diabetes: Evaluating the Role of Probiotics in a Rat Model of Diabetic Kidney Disease

Leech Granules Inhibit Ferroptosis and Alleviate Renal Injury in Mice with Diabetic Kidney Disease

Ethnopharmacological relevanceThe underlying mechanisms of diabetic kidney disease (DKD) and effective treatment strategies remain unclear. DKD progression is closely associated with abnormal iron metabolism and ferroptosis in vivo. Leeches, used in traditional Chinese medicine for promoting blood circulation and resolving blood stasis, are utilized to treat diabetes and its associated complications. Leeches effectively antagonize oxidative stress injury and exert protective effects on renal function. However, whether leeches can inhibit ferroptosis by modulating oxidative stress and iron metabolism remains unclear. Aim of the studyTo investigate the therapeutic potential of leech granules in DKD and, specifically, their effects on ferroptosis. Materials and methodsWe used a mouse model of DKD. The mice were treated with leech granules via gavage. Component identification and analysis of leech granules were performed using UPLC-MS, and efficacy was assessed by histopathology and analysis of blood glucose, lipids, and renal function. Additionally, the pharmacological mechanisms of leech granules were explored via proteomics, immunohistochemical staining, western blotting, and cell culture. ResultsProteomic analysis showed that iron metabolism was dysregulated and ferroptosis increased in DKD mice. Leech granules significantly reduced iron accumulation and renal pathological damage, decreased ROS levels, upregulated GSH levels, and inhibited ferroptosis in the kidneys of DKD mice. Furthermore, in vitro cellular experiments demonstrated that leech granules could inhibit erastin-induced ferroptosis and protect renal cells. ConclusionsThe regulation of renal iron metabolism and inhibition of ferroptosis mediates the therapeutic effect of leech granules on DKD. Leech granules represent a promising approach for DKD treatment.

Podocyte-specific KLF6 primes proximal tubule CaMK1D signaling to attenuate diabetic kidney disease

Diabetic kidney disease (DKD) is the main cause of chronic kidney disease worldwide. While injury to the podocytes, visceral epithelial cells that comprise the glomerular filtration barrier, drives albuminuria, proximal tubule (PT) dysfunction is the critical mediator of DKD progression. Here, we report that the podocyte-specific induction of human KLF6, a zinc-finger binding transcription factor, attenuates podocyte loss, PT dysfunction, and eventual interstitial fibrosis in a male murine model of DKD. Utilizing combination of snRNA-seq, snATAC-seq, and tandem mass spectrometry, we demonstrate that podocyte-specific KLF6 triggers the release of secretory ApoJ to activate calcium/calmodulin dependent protein kinase 1D (CaMK1D) signaling in neighboring PT cells. CaMK1D is enriched in the first segment of the PT, proximal to the podocytes, and is critical to attenuating mitochondrial fission and restoring mitochondrial function under diabetic conditions. Targeting podocyte-PT signaling by enhancing ApoJ-CaMK1D might be a key therapeutic strategy in attenuating the progression of DKD.

The Retinal Blood Flow Density Is Related to the Pathological Severity of Diabetic Kidney Disease

Introduction: This study aimed to investigate the correlation between fundus blood flow parameters and the severity of pathological biopsy in patients with diabetic kidney disease (DKD). Methods: Data of patients with type 2 diabetes mellitus who completed renal pathology biopsies and optical coherence tomography angiography (OCTA) examinations, including renal function, 24-h urine protein quantification, and macular flow imaging, were collected. DKD pathology biopsies were graded as stages 1–4, and differences and correlations of the parameters were compared between groups. The grading was transformed into early (stage 1) and late (stages 2–4), and regression analyses were conducted to develop a model, draw a nomogram, and test efficacy. Results: This study included 157 eyes from 157 individuals in total. Urinary microalbumin and to urinary creatinine ratio (mALB/NCR) increased with pathological grading, whereas while glomerular filtration rate was decreased (p < 0.01). Corresponding retinal blood flow in superficial, deep, and full paracentral rings was decreased, which correlated with pathological grading (p < 0.01), with the highest blood flow density in the whole layer (r2 = −0.707). Meaningfully, in the early DKD model (area under the curve = 0.929 [0.889–0.970], p < 0.01), whole-layer blood flow density, mALB/NCR, and diabetes duration were statistically significant. Conclusions: The decrease in macular retinal blood flow density detected by OCTA is closely associated with the increase in pathological grading of DKD and can be used as a noninvasive parameter for monitoring early changes in DKD.

VEPTP inhibition with an extracellular domain targeting antibody did not restore albuminuria in a mouse model of diabetic kidney disease.

Diabetic kidney disease (DKD) is the leading cause of end-stage kidney disease. DKD is a heterogeneous disease with complex pathophysiology where early endothelial dysfunction is associated with disease progression. The Tie2 receptor and Angiopoietin 1 and 2 ligands are critical for maintaining endothelial cell permeability and integrity. Tie2 signaling is negatively regulated by the endothelial specific transmembrane receptor Vascular Endothelial Protein Tyrosine Phosphatase (VEPTP). Genetic deletion of VEPTP protects from hypertension and diabetes induced renal injury in a mouse model of DKD. Here, we show that VEPTP inhibition with an extracellular domain targeting VEPTP antibody induced Tie2 phosphorylation and improved VEGF-A induced vascular permeability both invitro and invivo. Treatment with the VEPTP blocking antibody decreased the renal expression of endothelial activation markers (Angpt2, Edn1, and Icam1) but failed to improve kidney function in db/db uninephrectomized ReninAAV DKD mice.

Upregulation of Metrnl improves diabetic kidney disease by inhibiting the TGF-β1/Smads signaling pathway: A potential therapeutic target.

This study comprises an investigation of the role of meteorin-like (Metrnl) in an experimental model of diabetic kidney disease (DKD). Twenty-four db/db mice were randomly assigned to one of the following groups: DKD, DKD + Metrnl-/-, and DKD + Metrnl+/+. Plasma Metrnl concentrations were measured using ELISA. Kidney tissues were examined via western blotting, qRT-PCR, and immunohistochemistry to determine the expression levels of inflammatory factors. Electron microscopy was employed to observe stained kidney sections. Compared with the NC group, FBG, BW, and UACR were elevated in the DKD and Metrnl-/- groups, with severe renal pathological injury, decreased serum Metrnl concentration, decreased renal Metrnl expression, and increased expression levels of TNF-α, TGF-β1, TGF-R1, pSmad2, pSmad3, and α-SMA. In contrast, the Metrnl+/+ group showed decreased FBG and UACR, BUN, TC and TG, increased HDL-C and serum Metrnl concentration, increased renal Metrnl expression, and decreased expression of TNF-α, TGF-β1, TGF-R1, pSmad2, pSmad3, and α-SMA, compared to the DKD and Metrnl-/- groups. A Pearson bivariate correlation analysis revealed a negative correlation between UACR and Metrnl, and a positive correlation between UACR and TGF-β1. Upregulation of renal Metrnl expression can improve renal injury by downregulating the expression of molecules in the TGF-β1/Smads signaling pathway in the renal tissues of type 2 diabetic mice; and by reducing the production of fibrotic molecules such as α-SMA.

Liraglutide ameliorates diabetic kidney disease by modulating gut microbiota and L-5-Oxoproline

The gut microbiome-metabolites-kidney axis is a potential target for treating diabetic kidney disease (DKD). Our previous study found that Liraglutide attenuated DKD in rats by decreasing renal tubular ectopic lipid deposition (ELD) and serum metabolites levels, including L-5-Oxoproline (5-OP). However, the response of gut microbiome-metabolites-kidney axis to Liraglutide in DKD rats and the effect of 5-OP on ELD remain unknown. In this study, Sprague-Dawley rats were used as an animal model of DKD. They were subjected to a high fat diet, streptozotocin and uninephrectomy, followed by Liraglutide treatment (0.4 mg/kg d). Additionally, HK-2 cells were incubated with 30 mM glucose and 200 μM palmitate for 24h, and exposed to different concentrations of 5-OP. In DKD rats, Liraglutide dramatically improved the renal tubule structure. It increased the Simpson index (F = 4.487, p = 0.035) and reduced the Actinobacteria-to-Bacteroidetes ratio (F = 6.189, p = 0.014). At the genus level, Liraglutide increased the relative abundance of Clostridium, Oscillospira, Sarcina, SMB53, and 02d06 while decreasing that of Allobaculum. Meanwhile, 13 metabolites were significantly altered after Liraglutide treatment. Multi-omics analysis found that 5-OP levels were positively correlated with Clostridium abundance but negatively correlated with renal injury related indicators. In HK-2 cells, 5-OP significantly reduced the ELD in a dose-dependent manner through inhibiting the expression of SREBP1 and FAS. Overall, the renoprotective effect of Liraglutide in DKD rats is linked to the improvement of the gut microbiota composition and increased serum 5-OP levels, which may reduce ELD in renal tubular cells by lowering lipid synthesis.

Vascular Endothelial Growth Factor-B Blockade with CSL346 in Diabetic Kidney Disease: A Phase 2A Randomized Controlled Trial.

Increased vascular endothelial growth factor B (VEGF-B) expression in patients with diabetic kidney disease (DKD) is associated with increased lipid deposition in glomerular podocytes. Reducing VEGF-B activity in animal models of DKD using an anti-VEGF-B antibody improved histological evidence of glomerular injury and reduced albuminuria; effects attributed to prevention of ectopic lipid deposition in the kidney. CSL346 is a novel humanized monoclonal antibody that binds VEGF-B with high affinity. Targeting VEGF-B in patients with type 2 diabetes mellitus may improve DKD progression markers. An international, randomized, double-blind, placebo-controlled, phase 2a study (NCT04419467) assessed CSL346 (8 mg/kg or 16 mg/kg subcutaneously every 4 weeks for 12 weeks) in participants with type 2 diabetes mellitus and a urinary albumin-to-creatinine ratio (UACR) ≥150 mg/g (17.0 mg/mmol), and eGFR >20 mL/min/1.73m2. Efficacy, safety/tolerability, pharmacokinetics, and pharmacodynamics of CSL346 were evaluated. The primary analysis compared the change from baseline in log-transformed UACR between the two CSL346 dose groups combined versus placebo at Week 16. In total, 114 participants were randomized. CSL346 did not significantly reduce UACR compared with placebo at Week 16 (combined CSL346 group difference from placebo 95% confidence interval]: 4.0% [-14.7, 26.8]). Furthermore, no effect was seen in participant subgroups (degree of kidney impairment or sodium-glucose cotransporter 2 [SGLT2] inhibitor use) or on urinary biomarkers reflecting proximal tubular injury. CSL346 was generally well tolerated; however, diastolic blood pressure was significantly higher with CSL346 16 mg/kg versus placebo from Week 2 onwards, with differences ranging from +3.8 to +5.3 mmHg (P = 0.002 at Week 16). CSL346 did not reduce UACR compared with placebo at 16 weeks in participants with type 2 diabetes mellitus and DKD, and was associated with an increase in diastolic blood pressure.

Fufang Zhenzhu Tiaozhi (FTZ) capsule ameliorates diabetic kidney disease in mice via inhibiting the SGLT2/glycolysis pathway

Ethnopharmacological relevanceFufang Zhenzhu Tiaozhi (FTZ) capsule is a hospital preparation of a patented traditional Chinese medicine compound. FTZ has been clinically used for nearly 13 years in the treatment of diabetes and glycolipid metabolic diseases. With the significant benefits of SGLT2 inhibitor in patients with diabetic kidney disease (DKD), it provides a research avenue to explore the mechanism of FTZ in treating this disease based on glycolysis pathway. Aim of the studyTo explore the pharmacological characteristics of FTZ in DKD mice and its impact on the glycolysis pathway. Materials and methodsWe induced a DKD model in C57BL/6 mice by injection of streptozotocin (STZ) combined with long-term high-fat diet. We administered three doses of FTZ for 12 weeks of treatment. Kidney function, blood lipid levels, glucose tolerance, and key glycolytic enzymes were evaluated. Renal pathological changes were observed using HE, MASSON, and PAS staining. The potential targets of the active ingredients of FTZ in the glycolysis pathway were predicted using network pharmacology and molecular docking. Validation was performed using immunohistochemistry and Western blotting. ResultsFTZ effectively reduces blood glucose, total cholesterol, triglyceride, low density lipoprotein cholesterol, 24 h proteinuria, serum creatinine, blood urea nitrogen, and increases urinary glucose levels. Glucose tolerance and renal pathological changes were significantly improved by FTZ treatment. Pinusolidic acid, a component of FTZ, shows good binding affinity with three active pockets of SGLT2. WB and immunohistochemistry revealed that FTZ significantly inhibits the expression of SGLT2 and its glycolytic related proteins (GLUT2/PKM2/HK2). Hexokinase, pyruvate kinase, and lactate dehydrogenase in the kidney were also significantly inhibited by FTZ in a dose-dependent manner. ConclusionFTZ may alleviate the progression of DKD by inhibiting the activation of the SGLT2/glycolytic pathway. Our study provides new insights into the clinical application of FTZ in DKD.

Inhibition of TFEB deacetylation in proximal tubular epithelial cells (TECs) promotes TFEB activation and alleviates TEC damage in diabetic kidney disease.

The inhibition of the autophagolysosomal pathway mediated by transcription factor EB (TFEB) inactivation in proximal tubular epithelial cells (TECs) is a key mechanism of TEC injury in diabetic kidney disease (DKD). Acetylation is a novel mechanism that regulates TFEB activity. However, there are currently no studies on whether the adjustment of the acetylation level of TFEB can reduce the damage of diabetic TECs. In this study, we investigated the effect of Trichostatin A (TSA), a typical deacetylase inhibitor, on TFEB activity and damage to TECs in both invivo and invitro models of DKD. Here, we show that TSA treatment can alleviate the pathological damage of glomeruli and renal tubules and delay the DKD progression in db/db mice, which is associated with the increased expression of TFEB and its downstream genes. Invitro studies further confirmed that TSA treatment can upregulate the acetylation level of TFEB, promote its nuclear translocation, and activate the expression of its downstream genes, thereby reducing the apoptosis level of TECs. TFEB deletion or HDAC6 knockdown in TECs can counteract the activation effect of TSA on autophagolysosomal pathway. We also found that TFEB enhances the transcription of Tfeb through binding to its promoter and promotes its own expression. Our results, thus, provide a novel therapeutic mechanism for DKD that the alleviation of TEC damage by activating the autophagic lysosomal pathway through upregulating TFEB acetylation can, thus, delay DKD progression.

Effects of the S1P/S1PR1 Signaling Pathway on High Glucose-Induced NRK-52E Epithelial-Mesenchymal Transition Via Regulation of ROS/NLRP3.

Diabetic kidney disease (DKD) is the most significant complication in diabetic patients, ultimately leading to renal fibrosis. The most important manifestation of DKD is the epithelial-mesenchymal transition (EMT) of renal tubular cells, which can lead to renal fibrosis and inflammatory injury in special situations. Sphingosine 1-phosphate (S1P) is involved in various signal transduction pathways and plays a role through G protein-coupled receptors. Research has demonstrated that blocking the S1P / S1PR2pathway inhibits inflammation and fibrosis. However, the interaction between S1P/S1PR1and the pathophysiology of EMT remains ambiguous. The purpose of this study was to investigate the mechanism of S1P/S1PR1 on high glucose (HG)-induced renal EMT. We found that HG markedly increased the S1P and EMT marker levels in renal tubular epithelial cells. At the same time, HG could stimulate NF-κB/ROS/NLRP3 expression, but these phenomena were reversed after blocking S1PR1. In mice models of DKD, FTY720 (S1P antagonist) could significantly improve renal function and reduce the infiltration of inflammatory cells. ROS, as well as NLPR3 inflammasome, were markedly decreased in the treatment group. FTY720 inhibits extracellular matrix synthesis and improves renal fibrosis. In brief, the HG stimulates S1P/S1PR1 synthesis and activates the S1P/S1PR1 pathway. Through the S1P/S1PR1 pathway, activates NF-κB, promotes ROS generation and NLRP3 inflammasome activation, and ultimately causes EMT.

Machine Learning-Driven Prediction of Comorbidities and Mortality in Adults With Type 1 Diabetes.

Comorbidities such as cardiovascular disease (CVD) and diabetic kidney disease (DKD) are major burdens of type 1 diabetes (T1D). Predicting people at high risk of developing comorbidities would enable early intervention. This study aimed to develop models incorporating socioeconomic status (SES) to predict CVD, DKD, and mortality in adults with T1D to improve early identification of comorbidities. Nationwide Danish registry data were used. Logistic regression models were developed to predict the development of CVD, DKD, and mortality within five years of T1D diagnosis. Features included age, sex, personal income, and education. Performance was evaluated by five-fold cross-validation with area under the receiver operating characteristic curve (AUROC) and the precision-recall area under the curve (PR-AUC). The importance of SES was assessed from feature importance plots. Of the 6572 included adults (≥21 years) with T1D, 379 (6%) developed CVD, 668 (10%) developed DKD, and 921 (14%) died within the five-year follow-up. The AUROC (±SD) was 0.79 (±0.03) for CVD, 0.61 (±0.03) for DKD, and 0.87 (±0.01) for mortality. The PR-AUC was 0.18 (±0.01), 0.15 (±0.03), and 0.49 (±0.02), respectively. Based on feature importance plots, SES was the most important feature in the DKD model but had minimal impact on models for CVD and mortality. The developed models showed good performance for predicting CVD and mortality, suggesting they could help in the early identification of these outcomes in individuals with T1D. The importance of SES in individual prediction within diabetes remains uncertain.

Reconstituted HDL ameliorated renal injury of diabetic kidney disease in mice.

Diabetic kidney disease (DKD) is a devastating kidney disease and lacks effective therapeutic interventions. The present study was aimed to determine whether reconstituted high-density lipoprotein (rHDL) ameliorated renal injury in eNOS-/- dbdb mice, a mouse model of DKD. Three groups of mice, wild type C57BLKS/J (non-diabetes), eNOS-/- dbdb (diabetes), and eNOS-/- dbdb treated with rHDL (diabetes+rHDL) with both males and females were used. The rHDL nanoparticles were administered to eNOS-/- dbdb mice at Week 16 at 5 μg/g body weight in ~100 μL of saline solution twice per week for 4 weeks via retroorbital injection. We found that rHDL treatment significantly blunted progression of albuminuria and GFR decline observed in DKD mice. Histological examinations showed that the rHDLs significantly alleviated glomerular injury and renal fibrosis, and inhibited podocyte loss. Western blots and immunohistochemical examinations showed that increased protein abundances of fibronectin and collagen IV in the renal cortex of eNOS-/- dbdb mice were significantly reduced by the rHDLs. Taken together, the present study suggests a renoprotective effect of rHDLs on DKD.

Chinese medicine Linggui Zhugan formula protects against diabetic kidney disease in close association with inhibition of proteinase 3-mediated podocyte apoptosis in mice

Ethnopharmacological relevanceLinggui-Zhugan (LGZG) comprises four herbs and is a classic formula in traditional Chinese medicine. There is strong clinical evidence of its pleiotropic effects in the prevention of diabetes and its related complications. Although several classes of drugs are currently available for clinical management of diabetic kidney disease (DKD), tight glycemic and/or hypertension control may not prevent disease progression. This study evaluated the therapeutic effect of the ethnopharmacological agent LGZG on DKD. Aim of the studyThis study aimed to investigate the effects of LGZG formula with standard quality control on experimental DKD and its related metabolic disorders in animal model. Meanwhile, the present study aimed to investigate regulatory effects of LGZG on renal proteinase 3 (PR3) to reveal mechanisms underlying renoprotective benefits of LGZG. Materials and methodsLGZG decoction was fingerprinted by high-performance liquid chromatography for quality control. An experimental model of DKD was induced in C57 BL/6J mice by a combination of high-fat diet feeding, uninephrectomy, and intraperitoneal injection of streptozocin. The LGZG decoction was administrated by daily oral gavage. ResultsTreatment with LGZG formula significantly attenuated DKD-like traits (including severe albuminuria, mesangial matrix expansion, and podocyte loss) and metabolic dysfunction (disordered body composition and dyslipidemia) in mice. RNA sequencing data revealed a close association of LGZG treatment with marked modulation of signaling pathways related to podocyte injury and cell apoptosis. Mechanistically, LGZG suppressed the DKD-triggered increase in renal PR3 and podocyte apoptosis. In-vitro incubation of mouse immortalized podocytes with LGZG-medicated serum attenuated PR3-mediated apoptosis. ConclusionOur data demonstrated that the LGZG formula protected against DKD in mice and was closely associated with its inhibitory effects on PR3-mediated podocyte apoptosis.

RIPK3 causes mitochondrial dysfunction and albuminuria in diabetic podocytopathy through PGAM5-Drp1 signaling

BackgroundReceptor-interacting protein kinase (RIPK)3 is an essential molecule for necroptosis and its role in kidney fibrosis has been investigated using various kidney injury models. However, the relevance and the underlying mechanisms of RIPK3 to podocyte injury in albuminuric diabetic kidney disease (DKD) remain unclear. Here, we investigated the role of RIPK3 in glomerular injury of DKD. MethodsWe analyzed RIPK3 expression levels in the kidneys of patients with biopsy-proven DKD and animal models of DKD. Additionally, to confirm the clinical significance of circulating RIPK3, RIPK3 was measured by ELISA in plasma obtained from a prospective observational cohort of patients with type 2 diabetes, and estimated glomerular filtration rate (eGFR) and urine albumin-to-creatinine ratio (UACR), which are indicators of renal function, were followed up during the observation period. To investigate the role of RIPK3 in glomerular damage in DKD, we induced a DKD model using a high-fat diet in Ripk3 knockout and wild-type mice. To assess whether mitochondrial dysfunction and albuminuria in DKD take a Ripk3-dependent pathway, we used single-cell RNA sequencing of kidney cortex and immortalized podocytes treated with high glucose or overexpressing RIPK3. ResultsRIPK3 expression was increased in podocytes of diabetic glomeruli with increased albuminuria and decreased podocyte numbers. Plasma RIPK3 levels were significantly elevated in albuminuric diabetic patients than in non-diabetic controls (p = 0.002) and non-albuminuric diabetic patients (p = 0.046). The participants in the highest tertile of plasma RIPK3 had a higher incidence of renal progression (hazard ratio [HR] 2.29 [1.05–4.98]) and incident chronic kidney disease (HR 4.08 [1.10–15.13]). Ripk3 knockout improved albuminuria, podocyte loss, and renal ultrastructure in DKD mice. Increased mitochondrial fragmentation, upregulated mitochondrial fission-related proteins such as phosphoglycerate mutase family member 5 (PGAM5) and dynamin-related protein 1 (Drp1), and mitochondrial ROS were decreased in podocytes of Ripk3 knockout DKD mice. In cultured podocytes, RIPK3 inhibition attenuated mitochondrial fission and mitochondrial dysfunction by decreasing p-mixed lineage kinase domain-like protein (MLKL), PGAM5, and p-Drp1 S616 and mitochondrial translocation of Drp1. ConclusionsThe study demonstrates that RIPK3 reflects deterioration of renal function of DKD. In addition, RIPK3 induces diabetic podocytopathy by regulating mitochondrial fission via PGAM5-Drp1 signaling through MLKL. Inhibition of RIPK3 might be a promising therapeutic option for treating DKD.

Euonymus alatus delays progression of diabetic kidney disease in mice by regulating EGFR tyrosine kinase inhibitor resistance signaling pathway

To explore the therapeutic mechanism of Euonymus alatus for diabetic kidney disease (DKD). TCMSP, PubChem and Swiss Target Prediction databases were used to obtain the active ingredients in Euonymus alatus and their targets. GEO database and R language were used to analyze the differentially expressed genes in DKD. The therapeutic targets of DKD were obtained using GeneCards, DisGeNet, OMIM and TTD databases. The protein-protein interaction network and the "drug-component-target-disease" network were constructed for analyzing the topological properties of the core targets, which were functionally annotated using GO and KEGG pathway enrichment analyses. Molecular docking was performed for the core targets and the main pharmacologically active components, and the results were verified in db/db mice. Analysis of GSE96804, GSE30528 and GSE30529 datasets (including 60 DKD patients and 45 normal samples) identified 111 differentially expressed genes in DKD. Network pharmacology analysis obtained 161 intersecting genes between the target genes of Euonymus alatus and DKD, including the key core target genes SRC, EGFR, and AKT1. The core active ingredients of Euonymus alatus were quercetin, kaempferol, diosmetin, and naringenin, which were associated with responses to xenobiotic stimulionus and protein phosphorylation and regulated EGFR tyrosine kinase inhibitor resistance pathways. Molecular docking suggested good binding activities of the core active components of Euonymus alatus with the core targets. In db/db mouse models of DKD, treatment with Euonymus alatus obviously ameliorated kidney pathologies, significantly inhibited renal expressions of SRC, EGFR and AKT1, and delayed the progression of DKD. Euonymus alatus contains multiple active ingredients such as quercetin, kakaferol, diosmetin, naringenin, which regulate the expressions of SRC, EGFR, and AKT1 to affect the EGFR tyrosine kinase inhibitor resistance signaling pathway to delay the progression of DKD.

Tonabersat suppresses priming/activation of the NOD-like receptor protein-3 (NLRP3) inflammasome and decreases renal tubular epithelial-to-macrophage crosstalk in a model of diabetic kidney disease

BackgroundAccompanied by activation of the NOD-like receptor protein 3 (NLRP3) inflammasome, aberrant connexin 43 (Cx43) hemichannel-mediated ATP release is situated upstream of inflammasome assembly and inflammation and contributes to multiple secondary complications of diabetes and associated cardiometabolic comorbidities. Evidence suggests there may be a link between Cx43 hemichannel activity and inflammation in the diabetic kidney. The consequences of blocking tubular Cx43 hemichannel-mediated ATP release in priming/activation of the NLRP3 inflammasome in a model of diabetic kidney disease (DKD) was investigated. We examined downstream markers of inflammation and the proinflammatory and chemoattractant role of the tubular secretome on macrophage recruitment and activation.MethodsAnalysis of human transcriptomic data from the Nephroseq repository correlated gene expression to renal function in DKD. Primary human renal proximal tubule epithelial cells (RPTECs) and monocyte-derived macrophages (MDMs) were cultured in high glucose and inflammatory cytokines as a model of DKD to assess Cx43 hemichannel activity, NLRP3 inflammasome activation and epithelial-to-macrophage paracrine-mediated crosstalk. Tonabersat assessed a role for Cx43 hemichannels.ResultsTranscriptomic analysis from renal biopsies of patients with DKD showed that increased Cx43 and NLRP3 expression correlated with declining glomerular filtration rate (GFR) and increased proteinuria. In vitro, Tonabersat blocked glucose/cytokine-dependant increases in Cx43 hemichannel-mediated ATP release and reduced expression of inflammatory markers and NLRP3 inflammasome activation in RPTECs. We observed a reciprocal relationship in which NLRP3 activity exacerbated increased Cx43 expression and hemichannel-mediated ATP release, events driven by nuclear factor kappa-B (NFκB)-mediated priming and Cx43 hemichannel opening, changes blocked by Tonabersat. Conditioned media (CM) from RPTECs treated with high glucose/cytokines increased expression of inflammatory markers in MDMs, an effect reduced when macrophages were pre-treated with Tonabersat. Co-culture using conditioned media from Tonabersat-treated RPTECs dampened macrophage inflammatory marker expression and reduced macrophage migration.ConclusionUsing a model of DKD, we report for the first time that high glucose and inflammatory cytokines trigger aberrant Cx43 hemichannel activity, events that instigate NLRP3-induced inflammation in RPTECs and epithelial-to-macrophage crosstalk. Recapitulating observations previously reported in diabetic retinopathy, these data suggest that Cx43 hemichannel blockers (i.e., Tonabersat) may dampen multi-system damage observed in secondary complications of diabetes.

Proteomic and lipidomic analysis of the mechanism underlying astragaloside IV in mitigating ferroptosis through hypoxia-inducible factor 1α/heme oxygenase 1 pathway in renal tubular epithelial cells in diabetic kidney disease

Ethnopharmacological relevanceThe limitations of modern medicine in mitigating the pathological process of diabetic kidney disease (DKD) necessitate novel, precise, and effective prevention and treatment methods. Huangqi, the root of Astragalus membranaceus Fisch. ex Bunge has been used in traditional Chinese medicine for various kidney ailments. Astragaloside IV (AS-IV), the primary pharmacologically active compound in A. membranaceus, is involved in lipid metabolism regulation; however, its potential in ameliorating renal damage in DKD remains unexplored. Aim of the studyTo elucidate the specific mechanism by which AS-IV moderates DKD progression. Materials and methodsA murine model of DKD and high glucose-induced HK-2 cells were treated with AS-IV. Furthermore, multiomics analysis, molecular docking, and molecular dynamics simulations were performed to elucidate the mechanism of action of AS-IV in DKD, which was validated using molecular biological methods. ResultsAS-IV regulated glucose and lipid metabolism in DKD, thereby mitigating lipid deposition in the kidneys. Proteomic analysis identified 12 proteins associated with lipid metabolism regulated by AS-IV in the DKD renal tissue. Additionally, lipid metabolomic analysis revealed that AS-IV upregulated and downregulated 4 beneficial and 79 harmful lipid metabolites, respectively. Multiomics analysis further indicated a positive correlation between the top-ranked differential protein heme oxygenase (HMOX)1 and the levels of various harmful lipid metabolites and a negative correlation with the levels of beneficial lipid metabolites. Furthermore, enrichment of both ferroptosis and hypoxia-inducible factor (HIF)-1 signaling pathways during the AS-IV treatment of DKD was observed using proteomic analysis. Validation results showed that AS-IV effectively reduced ferroptosis in DKD-affected renal tubular epithelial cells by inhibiting HIF-1α/HMOX1 pathway activity, upregulating glutathione peroxidase-4 and ferritin heavy chain-1 expression, and downregulating acyl-CoA synthetase long-chain family member-4 and transferrin receptor-1 expression. Our findings demonstrate the potential of AS-IV in mitigating DKD pathology by downregulating the HIF-1α/HMOX1 signaling pathway, thereby averting ferroptosis in renal tubular epithelial cells. ConclusionsAS-IV is a promising treatment strategy for DKD via the inhibition of ferroptosis in renal tubular epithelial cells. The findings of this study may help facilitate the development of novel therapeutic strategies.