Syzygium cumini (L.) skeels mitigate diabetic nephropathy by regulating Nrf2 pathway and mitocyhondrial dysfunction: In vitro and in vivo studies.

ETHNOPHARMACOLOGICAL PREVALENCE: Hyperglycemia in diabetes increases the generation of advanced glycation end products (AGEs) through non-enzymatic reactions. The interaction between AGEs and their receptors (RAGE) leads to oxidative and inflammatory stress, which plays a pivotal role in developing diabetic nephropathy. Syzygium cumini (SC) L. (DC.) homeopathic preparations viz. 200C, 30C, and mother tincture [MT] are used to treat diabetes. This study aimed to elucidate the regulatory effects of SC preparations (200C, 30C, and MT) on the nuclear factor erythroid 2-related factor 2 (Nrf2) - nuclear factor-κB (NF-κB) pathways and mitochondrial dysfunction in mitigating diabetic nephropathy (DN). MATERIALS AND METHODS: Streptozotocin-induced diabetic rats were treated with SC preparations (200C, 30C, MT; 1:20 dilution in distilled water; 600 µL/kg body weight) and metformin (45 mg/kg body weight) twice daily for 40 days. DN was evaluated through biochemical parameters and histological examination. Renal tissue lysates were analyzed for glycation markers. Protein and gene levels of Nrf2, NF-κB, and mitochondrial dysfunctional signaling were determined via western blotting and RT-qPCR. An immunohistochemical analysis of the kidneys was performed. In vitro, human serum albumin (HSA - 10 mg/ml) was glycated with methylglyoxal (MGO - 55 mM) in the presence of SC preparations (200C, 30C, MT) for eight days. Glycated samples (400 µg/mL) were incubated with renal cells (HEK-293) for 24 h. Further reactive oxygen species production, Nrf2 nuclear translocation, and protein or gene expression of Nrf2 and apoptosis markers were analyzed by western blotting, RT-qPCR, and flow cytometry. Molecular docking of gallic and ellagic acid with the HSA-MGO complex was performed. RESULT: In vivo experiments using streptozotocin-induced diabetic rats treated with SC preparations exhibited improved biochemical parameters, preserved kidney function, and reduced glycation adduct formation in a dose-dependent manner. Furthermore, SC preparations downregulated inflammatory mediators such as RAGE, NF-κB, vascular endothelial growth factor (VEGF), and Tumor necrosis factor α (TNF-α) while upregulating the Nrf2-dependent antioxidant and detoxification pathways. They downregulated B-cell lymphoma 2 (Bcl-2) associated X-protein (BAX), C/EBP homologous protein (CHOP), Dynamin-related protein 1 (DRP1), and upregulated BCL 2 gene expression. Notably, SC preparations facilitated nuclear translocation of Nrf2, leading to the upregulation of antioxidant enzymes and the downregulation of oxidative stress markers. Molecular docking studies revealed favorable interactions between gallic (-5.26 kcal/mol) and ellagic acid (-4.71 kcal/mol) with the HSA-MGO complex. CONCLUSION: SC preparations mitigate renal cell apoptosis and mitochondrial dysfunction through Nrf2-dependent mechanisms.

Intestinal flora and bile acid interactions impact the progression of diabetic kidney disease.

In recent years, with the rapid development of omics technologies, researchers have shown that interactions between the intestinal flora and bile acids are closely related to the progression of diabetic kidney disease (DKD). By regulating bile acid metabolism and receptor expression, the intestinal flora affects host metabolism, impacts the immune system, and exacerbates kidney injury in DKD patients. To explore interactions among the gut flora, bile acids and DKD, as well as the related mechanisms, in depth, in this paper, we review the existing literature on correlations among the gut flora, bile acids and DKD. This review also summarizes the efficacy of bile acids and their receptors as well as traditional Chinese medicines in the treatment of DKD and highlights the unique advantages of bile acid receptors in DKD treatment. This paper is expected to reveal a new and important potential strategy for the clinical treatment of DKD.

Nanopore-based full-length transcriptome sequencing for understanding the underlying molecular mechanisms of rapid and slow progression of diabetes nephropathy.

BACKGROUND: Diabetic nephropathy (DN) has been a major factor in the outbreak of end-stage renal disease for decades. As the underlying mechanisms of DN development remains unclear, there is no ideal methods for the diagnosis and therapy. OBJECTIVE: We aimed to explore the key genes and pathways that affect the rate progression of DN. METHODS: Nanopore-based full-length transcriptome sequencing was performed with serum samples from DN patients with slow progression (DNSP, n = 5) and rapid progression (DNRP, n = 6). RESULTS: Here, transcriptome proclaimed 22,682 novel transcripts and obtained 45,808 simple sequence repeats, 1,815 transcription factors, 5,993 complete open reading frames, and 1,050 novel lncRNA from the novel transcripts. Moreover, a total of 341 differentially expressed transcripts (DETs) and 456 differentially expressed genes (DEGs) between the DNSP and DNRP groups were identified. Functional analyses showed that DETs mainly involved in ferroptosis-related pathways such as oxidative phosphorylation, iron ion binding, and mitophagy. Moreover, Functional analyses revealed that DEGs mainly involved in oxidative phosphorylation, lipid metabolism, ferroptosis, autophagy/mitophagy, apoptosis/necroptosis pathway. CONCLUSION: Collectively, our study provided a full-length transcriptome data source for the future DN research, and facilitate a deeper understanding of the molecular mechanisms underlying the differences in fast and slow progression of DN.

Sirt6 ameliorates high glucose-induced podocyte cytoskeleton remodeling via the PI3K/AKT signaling pathway.

BACKGROUND: Podocyte injury plays an important role in the occurrence and progression of diabetic kidney disease (DKD), which leads to albuminuria. Cytoskeletal remodeling is an early manifestation of podocyte injury in DKD. However, the underlying mechanism of cytoskeletal remodeling has not been clarified. Histone deacetylase sirtuin6 (Sirt6) has been found to play a key role in DKD progression, and the phosphatidylinositol 3-kinase (PI3K)/protein kinase B (PKB/AKT) pathway directly regulates the cytoskeletal structure of podocytes. Whereas, the relationship between Sirt6, the PI3K/AKT pathway and DKD progression remains unclear. METHODS: Renal injury of db/db mice was observed by PAS staining and transmission electron microscope. Expression of Sirt6 in the glomeruli of db/db mice was detected by immunofluorescence. UBCS039, a Sirt6 activator, was used to explore the renal effects of Sirt6 activation on diabetic mouse kidneys. We also downregulating Sirt6 expression in podocytes using the Sirt6 inhibitor, OSS_128167, and induced upregulation of Sirt6 using a recombinant plasmid, after which the effects of Sirt6 on high glucose (HG)-induced podocyte damage were assessed in vitro. Podocyte cytoskeletal structures were observed by phalloidin staining. The podocyte apoptotic rate was assessed by flow cytometry, and PI3K/AKT signaling activation was measured by Western blotting. RESULTS: Db/db mice exhibited renal damage including elevated urine albumin-to-creatinine ratio (ACR), increased mesangial matrix, fused podocyte foot processes, and thickened glomerular basement membrane. The expression of Sirt6 and PI3K/AKT pathway components was decreased in db/db mice. UBCS039 increased the expressions of Sirt6 and PI3K/AKT pathway components and ameliorated renal damage in db/db mice. We also observed consistent Sirt6 expression was in HG-induced podocytes in vitro. Activation of the PI3K/AKT pathway via a Sirt6 recombinant plasmid ameliorated podocyte cytoskeletal remodeling and apoptosis in HG-treated immortalized human podocytes in vitro, whereas Sirt6 inhibition by OSS_128167 accelerated HG-induced podocyte damage in vitro. CONCLUSIONS: Sirt6 protects podocytes against HG-induced cytoskeletal remodeling and apoptosis through activation of the PI3K/AKT signaling pathway. These findings provide evidence supporting the potential efficacy of Sirt6 activation as a promising therapeutic strategy for addressing podocyte injury in DKD.

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

BACKGROUND: The objective of our research was to investigate the specific mechanism of FTO in diabetic kidney disease (DKD) progression. METHODS: The 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-1ß 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. RESULTS: The 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. CONCLUSION: We found that FTO could inhibit the DKD progression in vivo and in vitro by regulated the m6A modification of NLRP3.

Metabolomic profiling reveals the step-wise alteration of bile acid metabolism in patients with diabetic kidney disease.

BACKGROUND: Diabetic kidney disease (DKD) is the major complication of diabetes concomitant with gut dysbiosis and glycometabolic disorder, which are strongly associated with bile acid (BA) metabolism. Yet studies investigating the BA metabolism involving in DKD pathogenesis are limited. This study aimed to explore the metabolomic profiling of BAs in DKD and analyze its association with DKD progression. METHODS: An ultra-performance liquid chromatography tandem mass spectrometry (UPLC-MS/MS) method was established to quantify BAs in the plasma, fecal and urine samples of patients with DKD or T2DM and healthy individuals (n = 30 for each group). The key BAs associated with DKD were identified by orthogonal partial least-squares discriminant analysis (OPLS-DA) and receiver-operating characteristic (ROC) curve. Polynomial regression and Pearson's correlation analyses were performed to assess the correlation between the key BAs and the clinical indicators reflecting DKD progression. RESULTS: Metabolomic profiling of 50 kinds of BAs presented the markedly step-wise alterations of BAs in plasma and feces as well as the little in urine of patients with DKD. Eight kinds of BAs in the plasma, eight kinds in the feces and three kinds in the urine were abnormally expressed, accompanying with the increased conjugated/unconjugated ratios of cholic acid, deoxycholic acid, chenodeoxycholic acid, ursodeoxycholic acid and hyocholic acid in the plasma, and of cholic acid, chenodeoxycholic acid and lithocholic acid in the feces. Moreover, the increased plasma level of glycochenodeoxycholic acid, and the increased fecal levels of glycolithocholic acid, 7-ketodeoxycholic acid and chenodeoxycholic acid-3-ß-D-glucuronide are strongly correlated with the clinical indicators reflecting DKD progression, including eGFR, 24 h urinary protein and 24 h urinary microalbumin. CONCLUSIONS: Our study for the first time disclosed the specific alterations of BA metabolism reflecting the step-wise progression of DKD, providing the basis for early identification and therapeutical strategies for DKD.

Factor XII signaling via uPAR-integrin ß1 axis promotes tubular senescence in diabetic kidney disease.

Coagulation factor XII (FXII) conveys various functions as an active protease that promotes thrombosis and inflammation, and as a zymogen via surface receptors like urokinase-type plasminogen activator receptor (uPAR). While plasma levels of FXII are increased in diabetes mellitus and diabetic kidney disease (DKD), a pathogenic role of FXII in DKD remains unknown. Here we show that FXII is locally expressed in kidney tubular cells and that urinary FXII correlates with kidney dysfunction in DKD patients. F12-deficient mice (F12-/-) are protected from hyperglycemia-induced kidney injury. Mechanistically, FXII interacts with uPAR on tubular cells promoting integrin ß1-dependent signaling. This signaling axis induces oxidative stress, persistent DNA damage and senescence. Blocking uPAR or integrin ß1 ameliorates FXII-induced tubular cell injury. Our findings demonstrate that FXII-uPAR-integrin ß1 signaling on tubular cells drives senescence. These findings imply previously undescribed diagnostic and therapeutic approaches to detect or treat DKD and possibly other senescence-associated diseases.

Repurposing Niclosamide to Modulate Renal RNA-Binding Protein HuR for the Treatment of Diabetic Nephropathy in db/db Mice.

Hu antigen R (HuR) plays a key role in regulating genes critical to the pathogenesis of diabetic nephropathy (DN). This study investigates the therapeutic potential of niclosamide (NCS) as an HuR inhibitor in DN. Uninephrectomized mice were assigned to four groups: normal control; untreated db/db mice terminated at 14 and 22 weeks, respectively; and db/db mice treated with NCS (20 mg/kg daily via i.p.) from weeks 18 to 22. Increased HuR expression was observed in diabetic kidneys from db/db mice, which was mitigated by NCS treatment. Untreated db/db mice exhibited obesity, progressive hyperglycemia, albuminuria, kidney hypertrophy and glomerular mesangial matrix expansion, increased renal production of fibronectin and a-smooth muscle actin, and decreased glomerular WT-1+-podocytes and nephrin expression. NCS treatment did not affect mouse body weight, but reduced blood glucose and HbA1c levels and halted the DN progression observed in untreated db/db mice. Renal production of inflammatory and oxidative stress markers (NF-κBp65, TNF-a, MCP-1) and urine MDA levels increased during disease progression in db/db mice but were halted by NCS treatment. Additionally, the Wnt1-signaling-pathway downstream factor, Wisp1, was identified as a key downstream mediator of HuR-dependent action and found to be markedly increased in db/db mouse kidneys, which was normalized by NCS treatment. These findings suggest that inhibition of HuR with NCS is therapeutic for DN by improving hyperglycemia, renal inflammation, and oxidative stress. The reduction in renal Wisp1 expression also contributes to its renoprotective effects. This study supports the potential of repurposing HuR inhibitors as a novel therapy for DN.

Expression of Autophagy Markers LC3B, LAMP2A, and GRP78 in the Human Kidney during Embryonic, Early Fetal, and Postnatal Development and Their Significance in Diabetic Kidney Disease.

Autophagy is the primary intracellular degradation system, and it plays an important role in many biological and pathological processes. Studies of autophagy involvement in developmental processes are important for understanding various processes. Among them are fibrosis, degenerative diseases, cancer development, and metastasis formation. Diabetic kidney disease is one of the main causes of chronic kidney disease and end-stage renal failure. The aim of this study was to investigate the immunohistochemical expression patterns of LC3B, LAMP2A, and GRP78 during different developmental stages of early-developing human kidneys and in samples from patients with type II diabetes mellitus. During the 7/8th DW, moderate expression of LC3B and LAMP2A and strong expression of GRP78 were found in the mesonephric glomeruli and tubules. In the 9/10th DW, the expression of LC3B and LAMP2A was even more pronounced in the mesonephric tubules. LC3B, LAMP2A, and GRP78 immunoreactivity was also found in the paramesonephric and mesonephric ducts and was stronger in the 9/10th DW compared with the 7/8th DW. In addition, the expression of LC3B, LAMP2A, and GRP78 also appeared in the mesenchyme surrounding the paramesonephric duct in the 9/10th DW. In the 15/16th DW, the expression of LC3B in the glomeruli was weak, that of LAMP2A was moderate, and that of GRP78 was strong. In the tubuli, the expression of LC3B was moderate, while the expression of LAMP2A and GRP78 was strong. The strongest expression of LC3B, LAMP2A, and GRP78 was observed in the renal medullary structures, including developing blood vessels. In postnatal human kidneys, the most extensive LC3B, LAMP2A, and GRP78 expression in the cortex was found in the epithelium of the proximal convoluted tubules, with weak to moderate expression in the glomeruli. The medullary expression of LC3B was weak, but the expression of LAMP2A and GRP78 was the strongest in the medullary tubular structures. Significantly lower expression of LC3B was found in the glomeruli of the diabetic patients in comparison with the nondiabetic patients, but there was no difference in the expression of LC3B in the tubule-interstitial compartment. The expression of LAMP2A was significantly higher in the tubule-interstitial compartments of the diabetic patients in comparison with the nondiabetic patients, while its expression did not differ in the glomeruli. Extensive expression of GRP78 was found in the glomeruli and the tubule-interstitial compartments, but there was no difference in the expression between the two groups of patients. These data give us new information about the expression of LC3B, LAMP2A, and GRP78 during embryonic, fetal, and early postnatal development. The spatiotemporal expression of LC3B, LAMP2A, and GRP78 indicates the important role of autophagy during the early stages of renal development. In addition, our data suggest a disturbance in autophagy processes in the glomeruli and tubuli of diabetic kidneys as an important factor in the pathogenesis of diabetic kidney disease.

The role of intercellular communication in diabetic nephropathy.

Diabetic nephropathy, a common and severe complication of diabetes, is the leading cause of end-stage renal disease, ultimately leading to renal failure and significantly affecting the prognosis and lives of diabetics worldwide. However, the complexity of its developmental mechanisms makes treating diabetic nephropathy a challenging task, necessitating the search for improved therapeutic targets. Intercellular communication underlies the direct and indirect influence and interaction among various cells within a tissue. Recently, studies have shown that beyond traditional communication methods, tunnel nanotubes, exosomes, filopodial tip vesicles, and the fibrogenic niche can influence pathophysiological changes in diabetic nephropathy by disrupting intercellular communication. Therefore, this paper aims to review the varied roles of intercellular communication in diabetic nephropathy, focusing on recent advances in this area.

Radix Astragali and Its Representative Extracts for Diabetic Nephropathy: Efficacy and Molecular Mechanism.

Diabetic nephropathy (DN) is a common microvascular complication of diabetes mellitus (DM). Radix Astragali (RA), a frequently used Chinese herbal medicine in the Leguminosae family, Astragalus genus, with its extracts, has been proven to be effective in DN treatment both in clinical practice and experimental studies. RA and its extracts can reduce proteinuria and improve renal function. They can improve histopathology changes including thickening of the glomerular basement membrane, mesangial cell proliferation, and injury of endothelial cells, podocytes, and renal tubule cells. The mechanisms mainly benefited from antioxidative stress which involves Nrf2/ARE signaling and the PPARγ-Klotho-FoxO1 axis; antiendoplasmic reticulum stress which involves PERK-ATF4-CHOP, PERK/eIF2α, and IRE1/XBP1 pathways; regulating autophagy which involves SIRT1/NF-κB signaling and AMPK signaling; anti-inflammation which involves IL33/ST2 and NF-κB signaling; and antifibrosis which involves TGF-ß1/Smads, MAPK (ERK), p38/MAPK, JNK/MAPK, Wnt/ß-catenin, and PI3K/AKT/mTOR signaling pathways. This review focuses on the clinical efficacy and the pharmacological mechanism of RA and its representative extracts on DN, and we further document the traditional uses of RA and probe into the TCM theoretical basis for its application in DN.

Huperzine A targets Apolipoprotein E: A potential therapeutic drug for diabetic nephropathy based on omics analysis.

AIMS: Diabetic nephropathy (DN) is a major complication of diabetes mellitus (DM) without curative interventions currently. Huperzine A (Hup A), a natural alkaloid, has demonstrated significant hypoglycemic and anti-inflammatory effects. We aim to investigate the protective effects of Hup A on DN and explore the underlying mechanisms METHODS: We applied STZ induced diabetic rats as DN model and leveraged combination analysis of the transcriptome, metabolome, microbiome, and network pharmacology (NP). The total effect of Hup A on DN was detected (i.e. urine protein, renal tissue structure) and the differential genes were further verified at the level of diabetic patients, db/db mice and cells. Clinical data and small interfering RNA (siRNA)-Apoe were adopted. RESULTS: Hup A alleviated kidney injury in DN rats. Transcriptomics data and Western blot indicated that the improvement in DN was primarily associated with Apoe and Apoc2. Additionally, metabolomics data demonstrated that DN-induced lipid metabolism disruption was regulated by Hup A, potentially involving sphingosine. Hup A also enriched microbial diversity and ameliorated DN-induced microbiota imbalance. Spearman's correlation analysis demonstrated significant associations among the transcriptome, metabolome, and microbiome. Apoe level was positively correlated with clinical biomarkers in DN patients. Si-Apoe also played protective role in podocytes. NP analysis also suggested that Hup A may treat DN by modulating lipid metabolism, microbial homeostasis, and apoptosis, further validating our findings. CONCLUSIONS: Collectively, we provide the first evidence of the therapeutic effect of Hup A on DN, indicating that Hup A is a potential drug for the prevention and treatment of DN.

Predicting prospective therapeutic targets of Bombyx batryticatus for managing diabetic kidney disease through network pharmacology analysis.

We conducted network pharmacology and molecular docking analyses, and executed in vitro experiments to assess the mechanisms and prospective targets associated with the bioactive components of Bombyx batryticatus in the treatment of diabetic kidney disease (DKD). The bioactive components and potential targets of B batryticatus were sourced from the Traditional Chinese Medicine Systems Pharmacology Database and Analysis Platform. Using 5 disease databases, we conducted a comprehensive screening of potential disease targets specifically associated with DKD. Common targets shared between the bioactive components and disease targets were identified through the use of the R package, and subsequently, a protein-protein interaction network was established using data from the STRING database. Gene Ontology and Kyoto Encyclopedia of Genes and Genomes enrichment analyses pertaining to the identified common targets were conducted using the Database for Annotation, Visualization, and Integrated Discovery. Molecular docking simulations involving the bioactive components and their corresponding targets were modeled through AutoDock Vina and Pymol. Finally, to corroborate and validate these findings, experimental assays at the cellular level were conducted. Six bioactive compounds and 142 associated targets were identified for B batryticatus. Among the 796 disease targets associated with DKD, 56 targets were identified. Gene Ontology and Kyoto Encyclopedia of Genes and Genomes pathway analyses revealed the involvement of these shared targets in diverse biological processes and signaling pathways, notably the PI3K-Akt signaling pathway. Molecular docking analyses indicated a favorable binding interaction between quercetin, the principal bioactive compound in B batryticatus, and RAC-alpha serine/threonine-protein kinase. Subsequently, in vitro experiments substantiated the inhibitory effect of quercetin on the phosphorylation level of PI3K and Akt. The present study provides theoretical evidence for a comprehensive exploration of the mechanisms and molecular targets by which B batryticatus imparts protective effects against DKD.

P4HB regulates the TGFß/SMAD3 signaling pathway through PRMT1 to participate in high glucose-induced epithelial-mesenchymal transition and fibrosis of renal tubular epithelial cells.

BACKGROUND: Diabetic nephropathy (DN) is a common complication of diabetes mellitus, and Prolyl 4-Hydroxylase Subunit Beta (P4HB) expression is increased in high glucose (HG)-induced renal tubular epithelial cells (TECs). But it's role in HG-induced TECs remains to be elucidated. METHODS: The HK-2 cells were induced using HG and transfected with SiRNA-P4HB. DCFH-DA staining was utilized for the detection of cellular levels of ROS. WB and immunofluorescence were utilized to detect the expression of P4HB, epithelial-mesenchymal transition (EMT), fibrosis, and TGFß/SMAD3-related proteins in HK-2 cells. Online databases were utilized for predicting the interaction target of P4HB, and immunoprecipitation (IP) experiments were employed to validate the binding of P4HB with the target. SiRNA and overexpression vectors of target gene were used to verify the mechanism of action of P4HB. RESULTS: HG induced an increase in the expression of P4HB and TGFß, p-SMAD3, and ROS in HK-2 cells. Furthermore, HG downregulated the expression of E-cadherin and upregulated the expression of N-cadherin, Vimentin, α-SMA, Fibronectin, Collagen IV, SNAIL, and SLUG in HK-2 cells. Interfering with P4HB significantly reversed the expression of these proteins. Database predictions and IP experiments showed that P4HB interacts with PRMT1, and the expression of PRMT1 was increased in HG-induced HK-2 cells. Interfering with PRMT1 inhibited the changes in expression of EMT and fibrosis related proteins induced by HG. However, overexpression of PRMT1 weakened the regulatory effect of P4HB interference on the EMT, fibrosis, and TGFß/SMAD3-related proteins in HK-2 cells. CONCLUSION: P4HB regulated the TGFß/SMAD3 signaling pathway through PRMT1 and thus participates in HG-induced EMT and fibrosis in HK-2 cells.

4-Octyl itaconate attenuates renal tubular injury in db/db mice by activating Nrf2 and promoting PGC-1α-mediated mitochondrial biogenesis.

Objectives: The aim of this study was to investigate the mechanism of itaconate's potential effect in diabetic kidney disease.Methods: Renal immune responsive gene 1 (IRG1) levels were measured in db/db mice and streptozotocin (STZ) + high-fat diet (HFD)-induced diabetic mice. Irg1 knockout mice were generated. db/db mice were treated with 4-octyl itaconate (4-OI, 50 mg/kg), a derivative of itaconate, for 4 weeks. Renal function and morphological changes were investigated. Ultrastructural alterations were determined by transmission electron microscopy.Results: Renal IRG1 levels were reduced in two diabetic models. STZ+HFD-treated Irg1 knockout mice exhibited aggravated renal tubular injury and worsened renal function. Treatment with 4-OI lowered urinary albumin-to-creatinine ratio and blood urea nitrogen levels, and restored renal histological changes in db/db mice. It improved mitochondrial damage, increased expressions of peroxisome-proliferator-activated receptor γ coactivator-1α (PGC-1α) and mitochondrial transcription factor A (TFAM) in the renal cortex of db/db mice. These were confirmed in vitro; 4-OI improved high glucose-induced abnormal mitochondrial morphology and TFAM expression in HK-2 cells, effects that were inhibited by PGC-1α silencing. Moreover, 4-OI reduced the number of apoptotic cells in the renal cortex of db/db mice. Further study showed that 4-OI increased renal Nrf2 expression and decreased oxidative stress levels in db/db mice. In HK-2 cells, 4-OI decreased high glucose-induced mitochondrial ROS production, which was reversed by Nrf2 silencing. Nrf2 depletion also inhibited 4-OI-mediated regulation of PGC-1α, TFAM, and mitochondrial apoptotic protein expressions.Conclusions: 4-OI attenuates renal tubular injury in db/db mice by activating Nrf2 and promoting PGC-1α-mediated mitochondrial biogenesis.

Integrating network pharmacology and experimental validation to decipher the pharmacological mechanism of DXXK in treating diabetic kidney injury.

Diabetes mellitus (DM) is a chronic metabolic disease that is highly susceptible to kidney injury. Di'ao XinXueKang capsules (DXXK) is a novel Chinese herbal medicine that has been used in clinical trials for the therapy of DM and kidney disease, but the underlying pharmacological mechanism remains unclear. This study aims to integrate network pharmacology, molecular docking and in vivo experiments to explore the potential mechanisms of DXXK in the treatment of diabetic kidney injury. The chemical constituents of DXXK were extracted from the ETCM and Batman-TCM databases, and then evaluated for their pharmacological activity via the Swiss ADME platform. Multiple disease databases were searched and integrated for DM-related targets. Overlapping targets were then collected to construct a protein-protein interaction (PPI) network. KEGG and GO enrichment analyses were performed based on the Metascape database, and molecular docking was performed using AutoDock Vina software. The main components in DXXK were analyzed by HPLC. The results of network pharmacology and molecular docking were validated in an animal model of DM induced by the combination of a high-fat diet (HFD) and streptozotocin (STZ). We screened and obtained 7 ingredients and identified dioscin, protodioscin, and pseudoprotodioscin as the major components of DXXK by HPLC. A total of 2,216 DM-related pathogenic genes were obtained from DrugBank, GeneCards, OMIM, and DisGeNET databases. KEGG and GO enrichment analyses indicated that the TGF-beta signaling pathway is a critical pathway associated with DM therapy. Molecular docking revealed that the ingredients in DXXK bind to the pivotal targets TGFß1, Smad2, and Smad3. In diabetic mice, we found that DXXK alleviated diabetic symptoms, lowered blood glucose, improved insulin tolerance, and modulated lipid metabolism. Furthermore, DXXK attenuated renal lesions and fibrosis by downregulating TGFß1, Smad2, and Smad3. Collectively, our results suggest that DXXK has the potential to regulate glucolipid metabolism in DM, and it may serve as a viable therapeutic option for renoprotection by inhibiting of the TGF-ß1/Smad2/3 pathway.

Synergistic modulation of endoplasmic reticulum stress pathway, oxidative DNA damage and apoptosis by ß-amyrin and metformin in mitigating hyperglycemia-induced renal damage using adult zebrafish model.

Diabetic nephropathy (DN) can be prevented with early therapeutic intervention in diabetic patients. Recent investigations suggest that ß-amyrin, a pentacyclic triterpenoid, could offer significant benefits with its potential antihyperglycemic and nephroprotective effects. We investigated the protective effects of ß-amyrin alone and combined it with metformin, the cornerstone therapy for diabetes, using a hyperglycemic adult Zebrafish (ZF) model. The ZF were subjected to hyperglycemia by immersing them in 111 mM glucose solutions. Treatment efficacy was assessed by measuring serum glucose and insulin levels and antioxidant, ER stress, apoptosis, and proinflammatory markers. ZF kidneys were also studied for immunohistochemistry and histopathology. Results revealed that the combined treatment of ß-amyrin and metformin resulted in a significant decrease (p ≤ 0.05) in blood glucose levels to 104.54 ± 1.63 mg/dL, in comparison to 388.75 ± 4.32 mg/dL in the untreated diseased control group. The reduction in hyperglycemia was more pronounced than treatment with either compound alone. Moreover, treatment with the combination restored renal function in diseased ZF, leading to significantly lower (p ≤ 0.05) serum urea (SU: 19.57 ± 1.61 mg/dL) and serum creatinine (SC: 0.56 ± 0.02 mg/dL) values compared to treatment with ß-amyrin (SU:27.02 ± 0.96 mg/dL; SC: 0.7 ± 0.01 mg/dL) or metformin (SU: 24.53 ± 1.29 mg/dL; SC: 0.6 ± 0.02 mg/dL) alone. The treatment also reduced oxidative stress markers, apoptosis and ER stress markers, and proinflammatory cytokines. Histopathological analysis showed improved renal architecture with significantly lower (p ≤ 0.05) renal tubular injury scores with the combination than with individual treatment. This study provides novel insights into the combined therapeutic effects of ß-amyrin and metformin in mitigating hyperglycemia-induced renal damage through key molecular pathways, highlighting a potentially effective therapeutic strategy for diabetic nephropathy. The findings hold promising translational relevance for developing combination therapies aimed at improving clinical outcomes in diabetic nephropathy patients.

Diabetic Kidney Disease: Contribution of Phenyl Sulfate Derived from Dietary Tyrosine upon Gut Microbiota Catabolism.

Deranged gut microbiota can release increased levels of uremic toxins leading to exacerbated kidney injury. In diabetic kidney disease (DKD), phenyl sulfate (PS) derived from tyrosine catabolism by gut microbiota has been demonstrated to be both an early diagnostic marker and a therapeutic target. In this perspective article, we summarize PS generation pathways and recent findings on PS and kidney injury in DKD. Increasing evidence has shown that the underlying mechanisms of PS-induced kidney injury mainly involve oxidative stress, redox imbalance, and mitochondrial dysfunction, which all may be targeted to attenuate PS-induced kidney injury. For future research directions, we think that a deeper understanding of the pathogenic role of PS in kidney injury using a variety of diabetic animal models should be investigated. Moreover, we also suggest beneficial approaches that could be used to mitigate the deleterious effect of PS on the kidney. These approaches include caloric restriction, tyrosine restriction, and administration of ketogenic drugs, ketogenic diets or natural products; all of which should be conducted under obese and diabetic conditions.

LncRNA PVT1 induces mitochondrial dysfunction of podocytes via TRIM56 in diabetic kidney disease.

Mitochondrial dysfunction is a significant contributor to podocyte injury in diabetic kidney disease (DKD). While previous studies have shown that PVT1 might play a vital role in DKD, the precise molecular mechanisms are largely unknown. By analyzing the plasma and kidney tissues of DKD patients, we observed a significant upregulation of PVT1 expression, which exhibited a positive correlation with albumin/creatinine ratios and serum creatinine levels. Then, we generated mice with podocyte-specific deletion of PVT1 (Nphs2-Cre/Pvt1flox/flox) and confirmed that the deletion of PVT1 suppressed podocyte mitochondrial dysfunction and inflammation in addition to ameliorating diabetes-induced podocyte injury, glomerulopathy, and proteinuria. Subsequently, we cultured podocytes in vitro and observed that PVT1 expression was upregulated under hyperglycemic conditions. Mechanistically, we demonstrated that PVT1 was involved in mitochondrial dysfunction by interacting with TRIM56 post-transcriptionally to modulate the ubiquitination of AMPKα, leading to aberrant mitochondrial biogenesis and fission. Additionally, the release of mtDNA and mtROS from damaged mitochondria triggered inflammation in podocytes. Subsequently, we verified the important role of TRIM56 in vivo by constructing Nphs2-Cre/Trim56flox/flox mice, consistently with the results of Nphs2-Cre/Pvt1flox/flox mice. Together, our results revealed that upregulation of PVT1 could promote mitochondrial dysfunction and inflammation of podocyte by modulating TRIM56, highlighting a potential novel therapeutic target for DKD.

Vitamin D receptor alleviates lipid peroxidation in diabetic nephropathy by regulating ACLY/Nrf2/Keap1 pathway.

The membrane lipid damage caused by reactive oxygen species(ROS) and various peroxides, namely lipid peroxidation, plays an important role in the progression of diabetic nephropathy (DN).We previously reported that vitamin D receptor(VDR) plays an active role in DN mice by modulating autophagy disorders. However, it is unclear whether the ATP-citrate lyase (ACLY)/NF-E2-related factor-2 (Nrf2)/Kelch-like ECH-associated protein 1 (Keap1) pathway is associated with the reduction of lipid peroxidation by VDR in the DN model. We found that in the DN mouse model, VDR knockout significantly aggravated mitochondrial morphological damage caused by DN, increased the expression of ACLY, promoted the accumulation of ROS, lipid peroxidation products Malondialdehyde(MDA) and 4-hydroxy-2-nonenal (4-HNE),consumed the Nrf2/Keap1 system, thus increasing lipid peroxidation. However, the overexpression of VDR and intervention with the VDR agonist paricalcitol (Pari) can reduce the above damage. On the other hand, cellular experiments have shown that Pari can significantly reduce the elevated expression of ACLY and ROS induced by advanced glycation end products (AGE). However, ACLY overexpression partially eliminated the positive effects of the VDR agonist. Next, we verified the transcriptional regulation of ACLY by VDR through chromatin immunoprecipitation (ChIP)-qPCR and dual luciferase experiments. Moreover, in AGE models, knockdown of ACLY decreased lipid peroxidation and ROS production, while intervention with Nrf2 inhibitor ML385 partially weakened the protective effect of ACLY downregulation. In summary, VDR negatively regulates the expression of ACLY through transcription, thereby affecting the state of Nrf2/Keap1 system and regulating lipid peroxidation, thereby inhibiting kidney injury induced by DN.