Search Results (66)

Diabetic nephropathy (DN) represents a severe microvascular complication of diabetes mellitus. As a Traditional Chinese Medicine (TCM) with extensive clinical applications, Ligustri Lucidi Fructus (LLF) exhibits significant anti-DN activity. However, the underlying pharmacological mechanisms, crucial components, and targets for LLF in DN treatment remain unclear. By integrating network pharmacology, molecular docking, and molecular dynamics simulations, the bioactive compounds, potential therapeutic targets, and underlying mechanisms of LLF in the treatment of DN were elucidated, followed by biological validation in a palmitic acid (PA)-induced MPC5 podocyte injury model. Among the 383 DN-related LLF targets identified, TNF emerged as a pivotal one, demonstrating potential binding interaction with the active components salidroside (Sal), apigenin (Api), and tormentic acid (TA). Moreover, Gene Expression Omnibus (GEO) database and KEGG enrichment analysis collectively highlighted the cytosolic DNA-sensing pathway. Notably, the cGAS-STING pathway is central to this pathway. Experimental studies further demonstrated that LLF-containing serum exerted a protective effect on MPC5 podocytes through cGAS-STING pathway suppression. Overall, these findings elucidate the pleiotropic mechanisms underlying LLF’s protective effects against DN, integrating compound–target–pathway interactions and thus offering a rationale for further investigation. Full article

Studies have emphasized alleviating fibrogenesis through interference with adenosine signaling in experimental diabetic nephropathy. We found that the in vivo antagonism of the adenosine A_2B receptor (A_2BAR) using MRS1754 in diabetic rats impedes the diabetes-induced glomerular expression of the mesenchymal-like transformation markers Snail and α-SMA, while the loss of the epithelial podocyte-specific proteins nephrin and ZO-1 was prevented. Furthermore, the production of MCP-1, CCL3, TGF-β, and the transcript levels of inflammatory mediators was reduced by A_2BAR antagonism. Using human podocytes in vitro, we demonstrated that A_2BAR antagonism affected the TGF-β-induced activation of SMAD2/-3, as evidenced by the attenuated phosphorylation of SMAD2/-3 and decreased SMAD3 occupancy at target gene promoters following the MRS1754 treatment. Moreover, the non-canonical activation of p65-NF-κB, the primary inflammatory signaling pathway downstream of TGF-β, and the expression of Snail were also reduced by MRS1754. We conclude that an A_2BAR blockade interferes with the pathogenic TGF-β signaling cascade responsible for the phenotypical transformation of podocytes, thereby alleviating diabetic glomerulopathy. Full article

Sodium orthovanadate is a non-selective protein tyrosine phosphatase inhibitor that can cause several types of kidney injury, including glomerulosclerosis, inflammation, and tubular damage. Cannabis is widely known for its medicinal use, and several studies have demonstrated its anti-diabetic and anti-inflammatory properties. The current study investigated the therapeutic effect of Lebanese cannabis oil extract (COE) against sodium orthovanadate-induced nephrotoxicity both in vitro and in vivo. Sprague Dawley male rats were intraperitoneally injected with 10 mg/kg sodium orthovanadate for 10 days followed by 5 mg/kg; 10 mg/kg; or 20 mg/kg intraperitoneal injection of cannabis oil extract, starting on day 4 until day 10. The body weight of the rats was monitored during the study, and clinical parameters, including serum urea, creatinine, and electrolytes, as well as kidney and heart pathology, were measured. Conditionally immortalized cultured rat podocytes were exposed to either sodium orthovanadate or selective phosphatase inhibitors, including DUSPi (DUSP1/6 inhibitor) and SF1670 (PTEN inhibitor), in the presence or absence of cannabis oil extract. MTS and an in vitro scratch assay were used to assess podocyte cell viability and migration, respectively. Western blot analysis was used to evaluate the phosphorylation levels of AKT and p38 MAPK. Rats injected with sodium orthovanadate displayed a marked reduction in body weight and an increase in serum creatinine and urea in comparison to the control non-treated group. All doses of COE caused a significant decrease in serum urea, with a significant decrease in serum creatinine observed at a dose of 20 mg/kg. Moreover, the COE treatment of rats injected with orthovanadate (20 mg/kg) showed a marked reduction in renal vascular dilatation, scattered foci of acute tubular necrosis, and numerous mitoses in tubular cells compared to the sodium orthovanadate-treated group. The cell viability assay revealed that COE reversed cytotoxicity induced by sodium orthovanadate and specific phosphatase inhibitors (DUSPi and SF1670) in rat podocytes. The in vitro scratch assay showed that COE partially restored the migratory capacity of podocytes incubated with DUSPi and SF1670. Time-course and dose-dependent experiments showed that COE (1 μg/mL) induced a significant increase in phospho-(S473)-AKT, along with a decrease in phospho (T180 + Y182) P38 levels. The current results demonstrated that Lebanese cannabis oil possesses important kidney protective effects against sodium orthovanadate-induced renal injury. Full article

Nephrin is an essential constituent of the slit diaphragm of the kidney filtering unit. Loss of nephrin expression leads to protein leakage into the urine, one of the hallmarks of kidney damage. Autoantibodies against nephrin have been reported in patients with minimal change disease and recurrent focal segmental glomerulosclerosis. Understanding the mechanism of nephrin loss may help improve or lead to the development of novel treatment strategies. In this study, we demonstrated the important function of miR-204-5p expression on the protection of nephrin from anti-nephrin antibodies present in nephrotoxic serum (NTS). In addition, we identified that aspartyl protease cathepsin D is one enzyme that may be involved in nephrin enzymatic degradation and that cathepsin D is a direct target of miR-204-5p gene regulation. The regulation of miR-204-5p expression was determined to be regulated by the long noncoding RNA Josd1-ps. In an NTS in vivo animal model, treatment with the pan aspartic protease inhibitor Pepstatin A ameliorated renal damage. Finally, we showed that the expression of miR-204-5p had a nephrin-protecting function in vitro. Developing a method of delivery of miR-204-5p specifically to podocytes in vivo may provide a novel method of nephroprotection against nephrin autoantibodies. Full article

The ubiquitin–proteasome system (UPS) and autophagy maintain protein homeostasis, which is critical to cellular function and survival. The dysregulation of these pathways has been recognized as a hallmark of acute kidney injury and chronic kidney disease. This review elucidates the role of the UPS and autophagy in kidney disease, namely through inflammation, oxidative stress, fibrosis and apoptosis. The pathways of NF-κB, TGF-β and mitochondrial failure result in glomerular injury and tubulointerstitial fibrosis due to impaired proteostasis in podocytes and tubular epithelial cells. Recent studies have revealed a connection between the autophagic process and the UPS, wherein compensatory mechanisms aim to spike down proteotoxic stress but eventually seem inadequate in cases of chronic derangement. Low-dose pharmacological inhibitors, autophagy modulators, and new gene and nanotechnology-based treatments may all help to restore the protein balance and reduce kidney injury. A more thorough understanding of these pathways is needed to develop kidney-protective and disease-modifying therapeutic interventions. Full article

Background/Objectives: The Sigma-1 receptor (Sigmar1), an intracellular chaperone protein, is ubiquitously expressed throughout the body, but its role in peripheral organs, such as the kidneys, remains unclear. Here, we investigated the protective effects and molecular mechanisms of SA4503, a selective Sigmar1 agonist, on Adriamycin (ADR)-induced renal glomerular injury. Methods: Using in vitro and in vivo models, we evaluated the effects of SA4503 on ADR-induced podocyte injury, including podocyte survival, albumin permeability, urinary albumin levels, and Sigmar1-nephrin interactions. NE-100, a Sigmar1 antagonist, was co-administered to validate the specificity of the effects of SA4503. Results: Sigmar1 was highly expressed in podocytes and mouse kidney tissues. SA4503 significantly reduced ADR-induced podocyte injury and urinary albumin leakage in mice. Mechanistically, SA4503 preserved Sigmar1-nephrin interactions, which were disrupted in ADR-treated kidneys. This protective effect was abolished by NE-100 co-treatment, confirming the Sigmar1-dependency of SA4503’s action. Conclusions: These findings demonstrate that the activation of Sigmar1 by SA4503 protects against ADR-induced podocyte injury and glomerular damage, likely by stabilizing Sigmar1-nephrin interactions. Therefore, Sigmar1 represents a promising therapeutic target for glomerular diseases such as nephrotic syndrome. Full article

Microalbuminuria is the earliest clinical abnormality in diabetic kidney disease. High glucose (HG) concentrations are associated with the induction of oxidative stress in podocytes, leading to disruption of the glomerular filtration barrier. Our recent study revealed a significant decrease in the membrane-bound fraction of Klotho in podocytes that were cultured under HG conditions. Given that disintegrin and metalloproteinase 17 (ADAM17) is responsible for the shedding of Klotho from the cell membrane, the present study investigated the impact of HG on the interplay between ADAM17 and Klotho in human podocytes. We demonstrated that ADAM17 protein levels significantly increased in urine, renal tissue, and glomeruli from diabetic rats, with a concomitant increase in glomerular albumin permeability. High glucose increased ADAM17 extracellular activity, NADPH oxidase activity, and albumin permeability in podocytes. These effects were reversed after treatment with ADAM17 inhibitor, in cells with downregulated ADAM17 expression, or after the addition of Klotho. Additionally, elevations of extracellular ADAM17 activity were observed in podocytes with the downregulation of Klotho expression. Our data indicate a novel mechanism whereby hyperglycemia deteriorates podocyte function via ADAM17 activation. We also demonstrated the ability of Klotho to protect podocyte function under hyperglycemic conditions in an ADAM17-dependent manner. Full article

Diabetic kidney disease (DKD) is a leading cause of chronic kidney disease (CKD) and end-stage renal disease worldwide, affecting approximately 40% of individuals with type 2 diabetes (T2DM) and 30% of those with type 1 diabetes (T1DM). As the prevalence of diabetes continues to rise, the burden of DKD is expected to grow correspondingly. This review explores the roles of key molecular pathways, including the apelinergic system, vascular endothelial growth factor (VEGF)/VEGF receptor (VEGFR) axis, and nitric oxide (NO)/nitric oxide synthase (NOS) signaling, in DKD pathogenesis and potential therapeutic applications. The apelinergic system, involving apelin and its receptor (APLNR), influences endothelial function, glucose metabolism, and renal health. Preclinical studies highlight its dual role in renal protection and injury through anti-inflammatory and antioxidant pathways, while other evidence suggests that it may exacerbate DKD through podocyte damage and angiogenesis. Similarly, the VEGF/VEGFR axis demonstrates a complex contribution to DKD, where VEGF-A promotes pathological angiogenesis and glomerular damage, but its inhibition requires careful modulation to prevent adverse effects. The NO/NOS system, integral to vascular and renal homeostasis, also exhibits altered activity in DKD, with reduced bioavailability linked to oxidative stress and inflammation. This review underscores the intricate interplay between these pathways in DKD, revealing both challenges and opportunities in their therapeutic targeting. Further research is essential to refine strategies and develop effective interventions for DKD management. Full article

Background/Objectives: High fructose has been implicated as an important trigger of kidney inflammation in patients and experimental models. Magnolol, isolated from Magnolia officinalis, has an anti-inflammatory effect, but its protective role in podocytes remains underexplored. This study explored the protective effects and underlying mechanism of magnolol against high fructose-induced podocyte inflammation. Methods: The effects of magnolol on high fructose-induced podocyte inflammation were assessed in male Sprague Dawley rats administered 10% (w/v) fructose water for 12 weeks and heat-sensitive human podocyte cell lines (HPCs) exposed to 5 mM fructose. Podocyte foot processes were examined using transmission electron microscopy. The expression levels of nephrin, podocin, tumor necrosis factor-α (TNF-α), Notch1 intracellular domain (NICD1), triokinase/FMN cyclase (TKFC), specificity protein 1 (Sp1) and histone deacetylase 4 (HDAC4) were determined by Western blot, immunofluorescence and real-time quantitative polymerase chain reaction (qRT-PCR). The chromatin immunoprecipitation (ChIP) assay was performed to evaluate the interaction between Sp1 and the promoter region of HDAC4. Results: Magnolol mitigated the impairment of glomerular filtration function in high fructose-fed rats. Besides, it significantly alleviated the inflammatory responses in glomeruli and HPCs, evidenced by decreased protein levels of TNF-α and NICD1. Increased protein levels of TKFC, Sp1 and HDAC4 were observed in high fructose-stimulated HPCs and rat glomeruli. TMP195, an HDAC4 inhibitor, reduced TNF-α and NICD1 protein levels in high fructose-exposed HPCs. The increased Sp1 was shown to associate with the promoter region of HDAC4, promoting HDAC4 protein expression in high fructose-exposed HPCs. The knockdown of TKFC in HPCs by TKFC siRNA decreased Sp1, HDAC4 and NICD1 protein levels, alleviating podocyte inflammatory response. Furthermore, magnolol inhibited TKFC/Sp1/HDAC4/Notch1 activation in vivo and in vitro. Conclusions: Magnolol attenuated high fructose-induced podocyte inflammation possibly through the suppression of TKFC/Sp1/HDAC4/Notch1 activation, providing new evidence for its potential role in podocyte protection. Full article

The endothelin system is reported to play a significant role in glomerular and tubulointerstitial kidney disease. In the kidney, endothelins are produced in mesangial cells and the glomerular basement membrane by the endothelium and podocytes. The endothelin system regulates glomerular function by inducing proliferation, increasing permeability and in effect proteinuria, and stimulating inflammation, tubular fibrosis, and glomerular scarring. Endothelin A receptor antagonists have been proven to delay the progression of chronic kidney disease and play a protective role in immunoglobulin A nephropathy, focal segmental glomerulosclerosis, and diabetic nephropathy. There are several ongoing research studies with ETAR antagonists in nondiabetic nephropathy, Alport disease, vasculitis and scleroderma nephropathy, which results are promising. Some reports suggest that the endothelin system might contribute to ischemia–reperfusion injury, acute graft rejection and deterioration of graft function. Endothelin inhibition in renal transplantation and its influence on graft survival is the future direction needing further research. The most frequent side effects associated with ETAR antagonists is fluid retention. Additionally, it should be considered if selective ETAR antagonists therapy needs to be co-administered with sodium-glucose co-transporter 2 inhibitors, renin–angiotensin–aldosterone inhibitors or diuretics and which patients should be recruited to such treatment to minimize the risk of adverse outcomes. Full article

Diabetic nephropathy (DN), one of the leading causes of end-stage kidney failure worldwide, is closely associated with high mortality in diabetic patients. However, therapeutic drugs for DN are still lacking. Ramulus Mori alkaloids (SZ-A), an effective component of alkaloids extracted from Ramulus Mori, have been found to improve glucose and lipid metabolism to mitigate diabetes and obesity; however, few studies have focused on their effects on DN progression. Thus, we investigated the protective role of SZ-A on DN through 16S rRNA sequencing, non-targeted metabolomics, and fecal microbiota transplantation (FMT) experiments. To address our hypothesis, we established the DN mouse model by combining a high-fat diet (HFD) with streptozotocin (STZ) injection. Herein, we demonstrated that SZ-A supplementation was recalcitrant to renal injury in DN mice, improving glomerular morphology, reversing the blood biochemistry parameters, and ameliorating podocyte injury. Importantly, the composition of the gut microbiota altered after SZ-A treatment, especially with the elevated abundance of Dubosiella and the increased level of serum pentadecanoic acid. FMT experiments further revealed that the gut microbiota exerted critical effects in mediating the beneficial roles of SZ-A. In vitro experiments proved that pentadecanoic acid administration improved podocyte apoptosis induced by AGEs. Taken together, SZ-A play a renoprotective role, possibly through regulating the gut microbiota and promoting pentadecanoic acid production. Our current study lends support to more extensive clinical applications of SZ-A. Full article

Background and Objectives: Cimicifugae Rhizoma, also known as ‘Sheng ma’ in Madeiran, is a widely used Chinese herbal medicine that has several pharmacological qualities, one of which is its antioxidant activity. Isoferulic acid, a prominent phenolic compound found in Cimicifugae Rhizoma, has potent antioxidant properties. This study was aimed to comprehensively analyze the components in Cimicifugae Rhizoma and rat plasma to evaluate the in vitro antioxidant and anti-inflammatory properties of Cimicifugae Rhizoma extract and Isoferulic acid as potential candidates for developing herbal formulations targeting podocyte injury in diabetic nephropathy for further clinical utilization. Materials and Methods: UPLC/Q-TOF-MS and HPLC were utilized as analytical tools to identify components of Cimicifugae Rhizoma extract or rat plasma after administrating it. MPC5 cells were cultured with H₂O₂ and high glucose and subjected to oxidative stress injury. The CXCL12/CXCR4 system plays a crucial role at certain stages of multiple kidney diseases’ injury. Apoptosis-related and target CXCL12/CXCR4/mTOR/Caspase-3 and Cask protein levels were assessed, and the levels of inflammatory-related factors, motility, morphology, ROS level, and apoptosis in podocytes were tested. Results: A total of 82 and 39 components were identified in the Cimicifugae Rhizoma extract and plasma, and Isoferulic acid content was determined as 6.52 mg/g in the Cimicifugae Rhizoma extract. The Cimicifugae Rhizoma extract (1 μg/mL) and Isoferulic acid (10, 25, 50 μM) considerably decreased high glucose and oxidative-stress-mediated toxicity, impaired mobility and adhesion and apoptotic changes in MPC5 cells, and reversed inflammation response. Moreover, the Cimicifugae Rhizoma extract and Isoferulic acid down-regulated Cask, mTOR, and Caspase-3, while significantly blocking the overactivation of CXCL12/CXCR4 in podocytes stimulated by oxidative stress and high glucose. Conclusions: These results indicate that the renal protective mechanism of the Cimicifugae Rhizoma extract and Isoferulic acid on simulating H₂O₂-induced podocyte injury involves mainly the of CXCL12/CXCR4 pathways and the inactivation of oxidative-stress-mediated apoptotic pathways after comprehensive qualitative and quantitative research by UPLC/Q-TOF-MS and HPLC. These findings provide an important efficacy and ingredient basis for further study on the clinical utilities of Cimicifugae Rhizoma and Isoferulic acid on podocyte and kidney impairment. Full article

Approximately 30% of steroid-resistant nephrotic syndromes are attributed to monogenic disorders that involve 27 genes. Mutations in KANK family members have also been linked to nephrotic syndrome; however, the precise mechanism remains elusive. To investigate this, podocyte-specific Kank1 knockout mice were generated to examine phenotypic changes. In the initial assessment under normal conditions, Kank1 knockout mice showed no significant differences in the urinary albumin-creatinine ratio, blood urea nitrogen, serum creatinine levels, or histological features compared to controls. However, following kidney injury with adriamycin, podocyte-specific Kank1 knockout mice exhibited a significantly higher albumin-creatinine ratio and a significantly greater sclerotic index than control mice. Electron microscopy revealed more extensive foot process effacement in the knockout mice than in control mice. In addition, KANK1-deficient human podocytes showed increased detachment and apoptosis following adriamycin exposure. These findings suggest that KANK1 may play a protective role in mitigating podocyte damage under pathological conditions. Full article

Induction of the adenosine receptor A_2B (A_2BAR) expression in diabetic glomeruli correlates with an increased abundance of its endogenous ligand adenosine and the progression of kidney dysfunction. Remarkably, A_2BAR antagonism protects from proteinuria in experimental diabetic nephropathy. We found that A_2BAR antagonism preserves the arrangement of podocytes on the glomerular filtration barrier, reduces diabetes-induced focal adhesion kinase (FAK) activation, and attenuates podocyte foot processes effacement. In spreading assays using human podocytes in vitro, adenosine enhanced the rate of cell body expansion on laminin-coated glass and promoted peripheral pY397-FAK subcellular distribution, while selective A_2BAR antagonism impeded these effects and attenuated the migratory capability of podocytes. Increased phosphorylation of the Myosin2A light chain accompanied the effects of adenosine. Furthermore, when the A_2BAR was stimulated, the cells expanded more broadly and more staining of pS19 myosin was detected which co-localized with actin cables, suggesting increased contractility potential in cells planted onto a matrix with a stiffness similar to of the glomerular basement membrane. We conclude that A_2BAR is involved in adhesion dynamics and contractile actin bundle formation, leading to podocyte foot processes effacement. The antagonism of this receptor may be an alternative to the intervention of glomerular barrier deterioration and proteinuria in the diabetic kidney disease. Full article

Investigating the role of podocytes in proteinuric disease is imperative to address the increasing global burden of chronic kidney disease (CKD). Studies strongly implicate increased levels of monocyte chemoattractant protein-1 (MCP-1/CCL2) in proteinuric CKD. Since podocytes express the receptor for MCP-1 (i.e., CCR2), we hypothesized that podocyte-specific MCP-1 production in response to stimuli could activate its receptor in an autocrine manner, leading to further podocyte injury. To test this hypothesis, we generated podocyte-specific MCP-1 knockout mice (Podo-Mcp-1^fl/fl) and exposed them to proteinuric injury induced by either angiotensin II (Ang II; 1.5 mg/kg/d, osmotic minipump) or Adriamycin (Adr; 18 mg/kg, intravenous bolus). At baseline, there were no between-group differences in body weight, histology, albuminuria, and podocyte markers. After 28 days, there were no between-group differences in survival, change in body weight, albuminuria, kidney function, glomerular injury, and tubulointerstitial fibrosis. The lack of protection in the knockout mice suggests that podocyte-specific MCP-1 production is not a major contributor to either Ang II- or Adr-induced glomerular disease, implicating that another cell type is the source of pathogenic MCP-1 production in CKD. Full article