Bortezomib (BTZ) is clinically important in the nephrological field because of its increasing use in plasma cell disorders and antibody-mediated kidney diseases, where it can both exert therapeutic benefits and, paradoxically, cause significant renal toxicity. This study investigated the protective effects of vanillic acid (VA) against BTZ-induced acute kidney injury using biochemical and molecular approaches. BTZ administration elevated serum creatinine, blood urea nitrogen, KIM-1 and NGAL, while co-treatment with VA partially normalized these markers. BTZ increased apoptotic markers (BAX, PUMA and TRAIL) and inflammatory cytokines (IL-1β, IL-6, TNF-α and IL-10), which were attenuated by VA. Oxidative stress-related genes NQO1, NOX4 and XO were upregulated, and GPX4 was downregulated by BTZ; VA restored these expressions. BTZ disrupted mitochondrial dynamics and energy metabolism (MFN2, CPT1A and OxPhos decreased; FIS1 increased), with VA ameliorating these changes. Energy imbalance induced by BTZ, reflected by reduced ATP and increased LDH and TAG, was also mitigated by VA. Podocyte proteins nephrin, podocin and CD2AP were reduced, accompanied by increased LAMP1 and decreased miR-204-5p; VA partially restored these levels. Overall, VA protected against BTZ-induced kidney injury via antioxidant, anti-inflammatory, antiapoptotic and mitochondrial mechanisms, potentially involving the miR-204-5p-nephrin axis.

Reducing the NFAT-uPAR signal of podocyte injury exerts the effect of Danggui-Shaoyao-San in improving proteinuria in nephrotic syndrome.

The Lepus yarkandensis (L. yarkandensis) is an endemic species inhabiting the arid ecosystem of the Tarim Basin, characterized by extreme dryness and scarce water resources. In contrast, Oryctolagus cuniculus (O. cuniculus) is adapted to temperate environments rich in water. Over the course of long-term evolution, the L. yarkandensis has likely developed unique physiological and histological adaptations to cope with the survival challenges posed by such arid conditions. This study aims to investigate the differences between the L. yarkandensis and O. cuniculus in terms of hematological and biochemical blood parameters, renal histology, water-salt regulation capacity, and the expression of glomerular filtration barrier proteins, in order to investigate the adaptive strategies of the L. yarkandensis to drought environments. The results showed that the L. yarkandensis exhibited higher red blood cell counts, hematocrit levels, urine osmolality, and total urinary protein levels compared to O. cuniculus, while the urine pH was lower. Histological analysis revealed increased collagen content in the outer medulla and more complex tubular structures in the kidneys of the L. yarkandensis. Molecular analysis further demonstrated upregulated expression of glomerular filtration barrier proteins nephrin, podocin, and CD2AP, alongside downregulated expression of laminin and WT1. In summary, these findings provide insights into the potential physiological and molecular adaptations of L. yarkandensis, laying the groundwork for future research into the evolution of desert fauna.

ObjectiveYi-Shen-Hua-Shi (YSHS) granules are a widely utilized Chinese medicine formula for treating diabetic kidney disease (DKD). Although their effectiveness in treating DKD is established, the precise regulatory mechanism remains unclear. We aimed to explore the potential targets and mechanisms of action of YSHS in delaying DKD progression through network pharmacology and experimental validation.MethodsNetwork pharmacology was employed to identify the potential targets and signaling pathways of YSHS in treating DKD, which was hypothesized to be associated with endoplasmic reticulum stress and apoptosis, and these predictions were validated through animal and cellular experiments. Following a 12-week YSHS intervention in db/db mice, assessments were conducted on blood glucose, lipid levels, renal function indices (24-h urinary protein, blood glucose, serum creatinine, blood urea, and urinary albumin-to-creatinine ratio), and kidney pathology. Apoptosis in mouse podocyte clone-5 (MPC-5) cells was assessed using TUNEL labeling. The expression levels of GRP78, PERK, p-PERK, CHOP, Bcl-2, Bax, and Nephrin proteins and mRNAs in mouse kidney tissues and MPC-5 cells were evaluated by immunohistochemistry, Western blotting, and real-time PCR.ResultsYSHS significantly improved the general status of db/db mice, with a significant reduction in body mass, renal function indices, total cholesterol, triglycerides, and low-density lipoprotein. Pathological staining showed reduced renal tissue damage in mice, and electron microscopy revealed reduced pedunculopontine fusion and basement membrane thickening. YSHS decreased GRP78, PERK, p-PERK, CHOP, and Bax proteins and mRNA levels in renal tissues and MPC-5 cells (p < 0.05 and p < 0.01) while increasing the expression level of Nephrin protein and Bcl-2 mRNA (p < 0.05 and p < 0.01).ConclusionYSHS inhibited podocyte apoptosis, protected the glomerular filtration barrier, attenuated proteinuria, and improved renal function indices by activating the GRP78/CHOP signaling pathway in the kidneys and the in vitro cultured podocytes of db/db mice.

Luteolin prevents axitinib-induced kidney damage in mice.

Disease recurrence after kidney transplantation (KTx) remains a major challenge in patients with primary focal segmental glomerulosclerosis (pFSGS). Antibodies targeting the slit diaphragm protein nephrin have been identified in patients with early disease recurrence. Here, we describe monitoring and effective pre-transplant elimination of anti-nephrin antibodies in an adolescent with pFSGS prior to living-donor KTx. Anti-nephrin antibodies were assessed in pre- and post-transplant serum samples by ELISA, Western blot and immunoprecipitation using three different nephrin proteins. Pre-transplant treatment including rituximab and repetitive therapeutic plasma exchanges resulted in effective and sustainable reduction of anti-nephrin antibodies. Allograft function has remained excellent without albuminuria over a follow-up of more than one year. Further analysis showed that the antibodies were cross-reactive with NEPH3 (filtrin), another key slit diaphragm protein. Monitoring and pre-transplant elimination of anti-slit diaphragm antibodies may become a standard, personalized approach in patients with pFSGS requiring KTx.

Circulating autoantibodies against the podocyte surface protein nephrin have recently been described in patients with podocytopathies, that is, minimal change disease, primary focal segmental glomerulosclerosis, and childhood idiopathic nephrotic syndrome. Their high specificity for podocytopathies in combination with a strong correlation with disease activity hold the potential for a non-invasive diagnosis, but prospective data are lacking. Here, we describe 3 patients with contraindications or unwillingness for a kidney biopsy, hampering a timely histological diagnosis and choice of appropriate therapy. In all patients, antinephrin autoantibodies were detected by quantitative immunoprecipitation, prompting the initiation of adequate treatment. These interventions induced a decrease in antinephrin autoantibody levels and clinical remission. Our study highlights the potential of antinephrin autoantibody measurement for a noninvasive diagnosis of antinephrin-associated podocytopathy.

Studies have emphasized alleviating fibrogenesis through interference with adenosine signaling in experimental diabetic nephropathy. We found that the in vivo antagonism of the adenosine A2B receptor (A2BAR) 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 A2BAR antagonism. Using human podocytes in vitro, we demonstrated that A2BAR 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 A2BAR blockade interferes with the pathogenic TGF-β signaling cascade responsible for the phenotypical transformation of podocytes, thereby alleviating diabetic glomerulopathy.

Autoantibodies against the podocyte protein nephrin were recently identified in a pediatric cohort primarily comprising steroid-sensitive (SSNS) and steroid-dependent (SDNS) nephrotic syndrome (NS). However, their prevalence across all NS subtypes, particularly in steroid-resistant nephrotic syndrome (SRNS), and their relation to therapy response need to be determined to advance pathophysiological understanding and refine treatment strategies. A multicenter cohort study measuring anti-nephrin autoantibodies in samples from children with SSNS, SDNS, nongenetic and genetic SRNS was conducted. Sixty-nine of 101 (68%) patients with SSNS, 19 of 67 (28%) patients with SDNS, 14 of 103 patients (14%) with non-genetic SRNS, and 1 of 62 patients (2%) with genetic SRNS were positive for anti-nephrin autoantibodies. The prevalence of anti-nephrin autoantibodies increased with presence of active disease in cases of SSNS and SDNS. Within the group of non-genetic SRNS patients with active disease, anti-nephrin positivity was found in 13 of 74 (18%) patients responding to intensified immunosuppression compared to none of 17 patients with multidrug-resistant SRNS. The prevalence of anti-nephrin antibodies is substantially higher in children with steroid responsive NS than in those with SRNS, suggesting that anti-nephrin antibodies primarily drive SSNS/SDNS. In contrast, NS due to podocyte gene mutations is primarily genotype-caused. Anti-nephrin autoantibodies may serve as a positive prognostic marker in pediatric NS, indicating a favorable response to immunosuppressive therapy.

Psoriasis may lead to glomerular inflammatory damage and disruption of the podocyte barrier, allowing podocyte degradation products to leak into the urine. We aimed to analyze the concentrations of podocyte surface glycoprotein podocalyxin (PDX) and podocyte slit protein nephrin in spot urine samples from patients with mild, moderate, or severe psoriasis vulgaris. A total of 78 participants, including 58 patients diagnosed with mild, moderate, or severe psoriasis vulgaris and 20 healthy controls, were included in the study. Psoriasis was diagnosed based on the typical morphological characteristics of the lesions. Morning urine samples were used to evaluate urine PDX and nephrin levels. Albuminuria was evaluated by calculating the urine albumin-to-creatinine ratio (uACR). Urinary PDX and nephrin levels were significantly higher in the psoriasis group than in the control group. Urinary PDX and nephrin levels in the mild and moderate psoriasis groups were similar but higher than those in the control group and significantly higher in the severe psoriasis group than in the mild and moderate psoriasis groups. The microalbuminuria rates were similar between the psoriasis and control groups. A significant positive correlation was observed between urine PDX, nephrin, uACR, and SBP. After adjusting for age, BMI, and sex, urine PDX and nephrin levels were found to be independent risk factors for microalbuminuria. This study showed that podocyte damage in patients with psoriasis begins in the early stages of the disease and significantly increases in the severe stage of the disease.

Introduction: Psoriasis may lead to glomerular inflammatory damage and disruption of the podocyte barrier, allowing podocyte degradation products to leak into the urine. Objectives: We aimed to analyze the concentrations of podocyte surface glycoprotein podocalyxin (PDX) and podocyte slit protein nephrin in spot urine samples of patients diagnosed with mild, moderate, or severe psoriasis vulgaris. Methods: A total of 78 participants, including 58 patients diagnosed with mild, moderate, or severe psoriasis vulgaris and 20 controls, were included in the study. The diagnosis of psoriasis was made considering the typical morphological appearance of the lesions. Morning urine samples were used to evaluate urine PDX and nephrin levels. Albuminuria was evaluated by calculating the albumin-creatinine ratio (uACR). Results: Urinary PDX and nephrin levels of psoriasis groups were significantly higher than the control group. Urinary PDX and nephrin levels of mild and moderate psoriasis groups were similar but higher than the control group. Urinary PDX and nephrin levels of the severe psoriasis group were significantly higher than the mild and moderate psoriasis groups. Microalbuminuria rates were similar in the psoriasis and control groups. A positive significant correlation was detected between urine PDX, nephrin, uACR, and SBP. After adjustment for age, BMI and gender, urine PDX and nephrin were found to be independent risk factors for microalbuminuria. Conclusion: This study showed that podocyte damage in psoriasis patients begins in the early stage of the disease and increases significantly in the severe stage of the disease.

Recent studies have identified autoantibodies targeting the podocyte protein nephrin in patients with primary podocytopathies such as minimal change disease, primary focal segmental glomerulosclerosis (FSGS), post-transplant recurrent FSGS and childhood idiopathic nephrotic syndrome. These antibodies bind nephrin and directly influence nephrin downstream signaling, with immense effect on the podocytes' cellular structure and function, substantially changing our understanding of antibody-mediated podocytopathies and disease classification. Their presence correlates with disease activity and holds great potential as a novel biomarker of anti-nephrin-associated podocytopathy. However, the detection of these potentially low-titre autoantibodies has proven challenging. In this review, we highlight and explain distinct detection methodologies with their advantages and disadvantages and discuss the potential of anti-nephrin autoantibodies as a novel biomarker in nephrotic syndrome for diagnosis, prognostication and therapeutic guidance in patients with nephrotic syndrome.

Introduction: Severe acute respiratory syndrome Coronavirus-2 (SARS-CoV-2) has been associated with the development of COVID-19. COVID-19 may cause endothelial cell dysfunction (ECD), which can lead to cardiometabolic diseases and podocytopathy. In this study, we explored whether presence of hyperglycemia predisposes to SARS-CoV-2 infection, in vitro, and whether COVID-19 can put an individual at a higher risk of persistent renal damage in the long-term following acute COVID infection. To estimate renal damage, we evaluated albuminuria and podocytopathy. Podocytopathy was estimated by measuring podocyte-specific protein levels in urine-derived exosomes from patients who were admitted with acute COVID-19 at 10 days, 6 months, and 12 months post-acute SARS-CoV-2 infection. Methods: Blood and urine samples from patients with SARS-CoV-2 post-infection were procured from the George Washington University COVID repository. Peripheral blood mononuclear cells and urine exosomes were isolated. Podocyte-specific proteins Podocalyxin (PODXL) and Nephrin (NEPH) were identified from urine exosomes. Results: Urine exosomal podocalyxin levels were significantly high at 10 week (n = 18; P = 0.001), 6 month (n = 25; P = 0.003) and 12 month (n = 14; P = 0.0001) time points. Nephrin levels were also noted to be high at 10 week (n = 18; P = 0.001) and 12 month (n = 14; P = 0.007) time points, compared with urine samples obtained from type 2 diabetes subjects who never had COVID-19. Though urinary podocyte-specific proteins were high, compared to control, there were no significant differences noted on urine albumin:creatinine ratios (UACR) between the groups. Conclusion: Persistent high levels of podocyte-specific proteins noted in urinary exosomes even at 12 months post-Covid may lead to the development of chronic kidney disease.

Diabetic nephropathy (DN) is one of the key causes of end-stage kidney disease worldwide, especially in developed countries. The classic pathogenic development of DN is characterized by microalbuminuria which would progress to nephrotic-range proteinuria and loss of kidney function. The degree of albuminuria is considered an independent risk factor for all-cause mortality in patients with DN. It is now well established that albuminuria stems from disruptions in podocyte structure and function. Podocytes play a major role in the glomerular filtration barrier. The nephrin protein has been identified as a core component of the slit diaphragm in podocytes, and as such, the downregulation of nephrin expression has been described well in various proteinuric glomerulopathies, including DN. Previous studies have shown that the presence of urinary nephrin potentially signifies an early marker of podocyte injury in DN. More recently, there have been increasing bodies of evidence which suggest that circulating autoantibodies targeting nephrin contributes to the pathogenesis of podocytopathies. However, the functional significance of these circulating autoantibodies in patients with DN is not well understood. In this review, we aim to evaluate the significance of nephrin dysregulation in the pathogenesis of DN based on the current available literature and provide an overview on the application of circulating anti-nephrin autoantibodies in relation to its diagnostic as well as prognostic role in podocytopathies, including DN.

Natriuretic peptides (NPs) bind to glomerular podocytes and attenuate glomerular injury. The beneficial effects of NPs are negatively regulated by the NP clearance receptor (NPRC), which is highly expressed in podocytes. To determine if inhibiting NPRC is podocyte protective, we examined the effects of deleting NPRC in both cultured podocytes and in vivo. We found that: 1.Both atrial NP and C-type NP inhibit podocyte apoptosis in cultured podocytes, but these podocyte protective effects are significantly attenuated in cells expressing NPRC, and 2. Atrial NP was significantly more effective than CNP at inhibiting the apoptotic response. Consistent with the protective actions of NPs, podocyte specific knockout of NPRC reduced albuminuria, glomerular sclerosis and tubulointerstitial inflammation in a mouse model of focal segmental glomerulosclerosis. These beneficial actions were associated with: 1. Decreased expression of the myofibroblast marker alpha-smooth muscle actin, 2. Reduced expression of the extracellular matrix proteins collagen 4-alpha-1 and fibronectin, and 3. Preserved expression of the podocyte proteins nephrin and podocin. Inhibiting NP clearance may be a useful therapeutic approach to treat glomerular diseases.

Sleep is an essential health requirement; human body needs sufficient amount and quality of sleep to ensure its health. Sleep disturbance led to deterioration in renal functions. This study aimed to asses effect of sleep disturbance on nephrin protein in renal corpuscle. A sample of thirty adult male albino rats, subjected to sleep disturbance by light, divided into three groups; control group with normal sleep rhythm of 12-12 h dark- light phases, group A: subjected to interruption of sleep by light at three intervals, group B: rats were exposed to a reduction in sleep time by continuous light stimulation for 7 h. Animals were sacrificed by euthanasia, their kidneys were dissected and prepared for paraffin, sections stained for Nephrin protein, and the immunohistochemical intensity was quantified by Aperio Image Scope analysis software. This study showed variations in the effect of sleep disturbance patterns by light exposure on nephrin protein expression in renal corpuscles; in the control group a strong patchy distribution of Nephrine in the peripheral region of the glomerulus, group A showed a significant reduction compared to the control group, and group B a weak expression of nephrin protein in the glomerulus, with significant changes between group B and group A, but no significant changes between group B and control. These changes reflect that sleep disturbance affects the structural integrity of the slit diaphragm and nephrin protein expression, which is considered a novel protein for the slit diaphragm structural integrity, and a sign of podocyte injury.

To investigate the protective effect of Yiqi Yangyin Huazhuo Tongluo Formula (YYHT) against high glucose-induced injury in mouse renal podocytes (MPC5 cells) and the possible mechanism. Adult Wistar rats were treated with 19, 38, and 76 g/kg YYHT or saline via gavage for 7 days to prepare YYHT-medicated or blank sera for treatment of MPC5 cells cultured in high glucose (30 mmol/L) prior to transfection with a miR-21a-5p inhibitor or a miR-21a-5p mimic. The changes in miR-21a-5p expressions and the mRNA levels of FoxO1, PINK1, and Parkin in the treated cells were detected with qRT-PCR, and the protein levels of nephrin, podocin, FoxO1, PINK1, and Parkin were detected with Western blotting. Autophagic activity in the cells were evaluated with MDC staining. The effect of miR-21a-5p mimic on FoxO1 transcription and the binding of miR-21a-5p to FoxO1 were examined with luciferase reporter gene assay and radioimmunoprecipitation assay. MPC5 cells exposed to high glucose showed significantly increased miR-21a-5p expression, lowered expressions of FoxO1, PINK1, and Parkin1 mRNAs, and reduced levels of FoxO1, PINK1, parkin, nephrin, and podocin proteins and autophagic activity. Treatment of the exposed cells with YYHT-medicated sera and miR-21a-5p inhibitor both significantly enhanced the protein expressions of nephrin and podocin, inhibited the expression of miR-21a-5p, increased the mRNA and protein expressions of FoxO1, PINK1 and Parkin, and upregulated autophagic activity of the cells. Transfection with miR-21a-5p mimic effectively inhibited the transcription of FoxO1 and promoted the binding of miR-21a-5p to FoxO1 in MPC5 cells, and these effects were obviously attenuated by treatment with YYHT-medicated sera. YYHT-medicated sera alleviate high glucose-induced injury in MPC5 cells by regulating miR-21a-5p/FoxO1/PINK1-mediated mitochondrial autophagy.

BackgroundDiabetes often causes diabetic nephropathy (DN), a serious long-term complication. It is characterized by chronic proteinuria, hypertension, and kidney function decline, can progress to end-stage renal disease, lowering patients’ quality of life and lifespan. Inflammation and apoptosis are key to DN development. Network pharmacology, clinical correlation, and basic experimental validation to find out how NGR1 might work to reduce inflammation in DN treatment. The study aims to improve DN treatment with new findings.MethodsTo determine how NGR1 treats DN, this study used network pharmacology, clinical correlation, and basic experimental validation. Three methods were used to predict NGR1 drug targets: ChEMBL, SuperPred, and Swiss Target Prediction. Drug targets are linked to diseases by molecular docking. A clinical correlation analysis using the Nephroseq Classic (V4) database looked at the strong link between medication targets and the development, progression, and renal function of DN. Additional research showed that NGR1 reduces high blood sugar-induced podocyte inflammation.ResultsThe integrin subunit beta 8 (ITGB8) protein is a potential NGR1 therapeutic target for DN. It may be linked to inflammatory proteins like caspase 3 and IL-18. Validation of the molecular docking showed that SER-407, ALA-22, Ala-343, and TYR-406 form hydrogen bonds with NGR1 and ITGB8. These interactions represent pharmacodynamic targets. Clinical correlation showed that DN patients had significantly lower ITGB8 expression levels than healthy individuals. Between 50 and 80 years old, DN patients’ ITGB8 expression levels decreased. ITGB8 expression was lowest in renal function conditions, with eGFR values of 15–29 ml/min/1.73 m2. In the db/db mouse model, downregulation of ITGB8 expression in renal tissue was associated with renal inflammatory damage. The hyperglycemic group had significantly lower levels of nephrin and caspase-3 protein, but higher levels of cleaved caspase-1 protein. Giving NGR1 in different amounts (1, 3, 10, and 30 µM) greatly decreased the expression of caspase3, stopped the expression of cleaved caspase1, and lowered the damage caused by NLRP3 in podocytes.ConclusionWe identified several NGR1 pharmacological targets and found that the ITGB8 protein is a key drug target linked to inflammation and DN. ITGB8 is critical for DN development and can help to reduce high blood sugar-induced podocyte inflammation.

Renal protective effect of Isaria felina mycelium powder on diet and STZ-induced diabetes mice and the identification of major chemical constituents

Diabetic nephropathy (DN) is the leading cause of end-stage renal disease, and effective treatment modalities that fully address its molecular etiology are lacking. Prior studies support that the stress response protein REDD1 (regulated in development and DNA damage 1) contributes to the development of diabetes complications. This study investigated a potential role for REDD1 expression in podocytes in diabetes-induced podocyte loss and compromised glomerular filtration. Podocyte-specific REDD1 deletion protected against renal injury, as evidenced by reduced albuminuria, glomerular hypertrophy, and mesangial matrix deposition in streptozotocin (STZ)-induced diabetic mice. Podocyte-specific REDD1 expression was required for diabetes-induced reduction in slit diaphragm (SD) proteins podocin and nephrin. Notably, podocyte-specific REDD1 deletion protected against podocytopenia and preserved glomerular basement membrane and foot process architecture in diabetic mice. In the kidneys of diabetic mice and in human podocyte cultures exposed to hyperglycemic conditions, REDD1 was necessary for increased expression of the transient receptor potential canonical 6 (TRPC6) channel. More specifically, REDD1 promoted nuclear factor-κB–dependent transcription of TRPC6, intracellular calcium entry, and cytoskeletal remodeling under hyperglycemic conditions. Overall, the findings provide new insight into the role of podocyte-specific REDD1 expression in renal pathology and support the possibility that therapeutics targeting REDD1 in podocytes could be beneficial for DN.Article HighlightsDiabetes-induced albuminuria and reduced glomerular slit diaphragm proteins were associated with increased kidney REDD1 protein abundance.Podocyte-specific deletion of REDD1 attenuated diabetes-induced slit diaphragm protein reduction and podocyte loss.REDD1 was required for nuclear factor-κB–dependent TRPC6 expression and increased cytoplasmic calcium levels in podocytes.Podocyte-specific expression of REDD1 was necessary for altered glomerular architecture and albuminuria in diabetic mice.