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There have been exciting advances in our knowledge of primary glomerular diseases and nephrotic syndromes in recent years. Beyond the histological pattern from renal biopsy, more precise phenotyping of the diseases and the use of modern nephrogenetics helps to improve treatment decisions and sometimes also avoid unnecessary exposure to potentially toxic immunosuppression. New biomarkers have led to easier and more accurate diagnoses and more targeted therapeutic decisions. The treatment landscape is becoming wider with a pipeline of promising new therapeutic agents with more sophisticated approaches. This review focuses on all aspects of entities that are associated with nephrotic syndromes with updated information on recent advances in each field. This includes podocytopathies (focal segmental glomerulosclerosis and minimal-change disease), membranous nephropathy, membranoproliferative glomerulonephritis, IgA nephropathy, fibrillary glomerulonephritis, amyloidosis, and monoclonal gammopathy of renal significance in the context of the nephrotic syndrome, but also renal involvement in systemic diseases, diabetic nephropathy, and drugs that are associated with nephrotic syndromes. [ABSTRACT FROM AUTHOR]

Background: Acromegaly is a rare disorder caused by excessive growth hormone (GH) secreted from a pituitary tumor. High levels of GH and insulin growth factor-1 can lead to renal hypertrophy, as well as to diabetes mellitus and hypertension, which negatively impact kidney function. It is believed that high GH may also be involved in the onset of diabetic nephropathy, the main cause of end-stage kidney disease in developed countries. Material and methods: This case–control study was conducted on 23 acromegalic patients and on a control group represented by 21 healthy subjects. The following parameters were determined for all the subjects: serum creatinine, serum urea, estimated glomerular filtration rate (eGFR), urinary albumin/creatinine ratio (UACR), nephrin and kidney injury molecule 1 (KIM-1). Results: Patients with acromegaly showed higher levels of UACR and lower levels of eGFR as compared to healthy subjects. No significant correlations were found between clinical or biochemical parameters associated with acromegaly and nephrin or KIM-1. Conclusions: There was no glomerular or proximal tubular damage at the time of the study, as proven by the normal levels of the biomarkers nephrin and KIM-1. Studies including more patients with uncontrolled disease are needed to clarify the utility of nephrin and KIM-1 for the detection of early kidney involvement in acromegalic patients. [ABSTRACT FROM AUTHOR]

Pringgodigdo Nugroho,1 Riahdo Juliarman Saragih,2 Aida Lydia,1 Muhadi Muhadi,3 Harry Isbagio,4,5 Hamzah Shatri,6 Carissa Cornelia Chundiawan,1 Fidel Hermanto1 1Division of Nephrology and Hypertension, Department of Internal Medicine, Faculty of Medicine, Universitas Indonesia—Dr. Cipto Mangunkusumo Hospital, Jakarta, Indonesia; 2Department of Internal Medicine, Faculty of Medicine, Universitas Indonesia—Dr. Cipto Mangunkusumo Hospital, Jakarta, Indonesia; 3Cardiovascular Division, Department of Internal Medicine, Faculty of Medicine, Universitas Indonesia—Dr. Cipto Mangunkusumo Hospital, Jakarta, Indonesia; 4Division of Rheumatology, Department of Internal Medicine, Faculty of Medicine, Universitas Indonesia—Dr. Cipto Mangunkusumo Hospital, Jakarta, Indonesia; 5Geriatric Division, Department of Internal Medicine, Faculty of Medicine, Universitas Indonesia—Dr. Cipto Mangunkusumo Hospital, Jakarta, Indonesia; 6Psychosomatic Division, Department of Internal Medicine, Faculty of Medicine, Universitas Indonesia—Dr. Cipto Mangunkusumo Hospital, Jakarta, IndonesiaCorrespondence: Pringgodigdo Nugroho, HDivision of Nephrology and Hypertension, Department of Internal Medicine, Faculty of Medicine Universitas Indonesia—Dr. Cipto Mangunkusumo Hospital Jl, Diponegoro no. 71, Jakarta, 10430, Indonesia, Email pringgodigdo.nugroho@ui.ac.idBackground: Diabetic kidney disease (DKD) is the leading cause of end-stage kidney disease, and podocytopathy is an early manifestation of DKD characterized by the urinary excretion of podocyte-specific proteins, such as nephrin and podocin. Asymmetric dimethylarginine (ADMA)—a biomarker of endothelial dysfunction—is associated with progressive kidney dysfunction. However, the mechanism of endothelial dysfunction in DKD progression is unclear. The aim of this study was to investigate the correlations of ADMA levels with nephrin, podocin, and the podocin:nephrin ratio (PNR) in DKD patients.Methods: A cross-sectional study of 41 DKD outpatients was performed in two hospitals in Jakarta from April–June 2023. The collected data included the subjects’ characteristics, histories of disease and medication, and relevant laboratory data. Serum ADMA was measured using liquid chromatography, while urinary podocin and nephrin were measured using the enzyme-linked immunosorbent assay (ELISA) method. A correlation analysis was performed to evaluate the correlation of ADMA with nephrin, podocin, and PNR. Regression analysis was performed to determine confounding factors.Results: The mean value of ADMA was 70.2 (SD 17.2) ng/mL, the median for nephrin was 65 (20– 283 ng/mL), and the median of podocin was 0.505 (0.433– 0.622) ng/mL. ADMA correlated significantly with nephrin (r = 0.353, p = 0.024) and PNR (r = − 0.360, p = 0.021), but no correlation was found between ADMA and podocin (r = 0.133, p = 0.409). The multivariate analysis showed that body mass index was a confounding factor.Conclusion: This study revealed weak positive correlations between ADMA and urinary nephrin and between ADMA and PNR. No correlation was found between ADMA and urinary podocin.Keywords: diabetic kidney disease, ADMA, nephrin, podocin, podocin:nephrin ratio

Background/Objectives: Glomerulopathy is a term used to describe a broad spectrum of renal diseases, characterized by dysfunction of glomerular filtration barrier, especially of podocytes. Several podocyte-associated proteins have been found and proved their usefulness as urine markers of podocyte dysfunction. Two of them are nephrin (NEP) and prodocalyxin (PDC). This study aims to evaluate the association of podocyte damage, as it is demonstrated via the concentrations of urinary proteins, with clinical and histological data from patients with several types of glomerulonephritis. Methods: We measured urine levels of two podocyte-specific markers, NEP and PDC (corrected for urine creatinine levels), in patients with a wide range of glomerulopathies. Serum and urine parameters as well as histological parameters from renal biopsy were recorded. Results: In total, data from 37 patients with glomerulonephritis and 5 healthy controls were analyzed. PDC and NEP concentrations correlated between them and with serum creatinine levels (p = 0.001 and p = 0.013 respectively), and with histological lesions associated with chronicity index of renal cortex, such as severe interstitial fibrosis, severe tubular atrophy and hyalinosis (for PDC/NEP, all p < 0.05). In addition, the PDC and NEP demonstrated statistically significant correlations with interstitial inflammation (p = 0.018/p = 0.028). Regarding electron microscopy evaluation, PDC levels were correlated with distinct characteristics, such as fibrils and global podocyte foot process fusion, whereas the NEP/CR ratio was uniquely significantly associated with podocyte fusion only in non-immune-complex-mediated glomerulonephritis (p = 0.02). Among the other clinical and histological parameters included in our study, a strong correlation between proteinuria >3 g/24 h and diffuse fusion of podocyte foot processes (p = 0.016) was identified. Conclusions: Podocalyxin and nephrin concentrations in urine are markers of podocyte dysfunction, and in our study, they were associated both with serum creatinine and histological chronicity indices. [ABSTRACT FROM AUTHOR]

Podocytes are involved in maintaining kidney function and are a major focus of research on diabetic kidney disease (DKD). Urinary biomarkers derived from podocyte fragments and molecules have been proposed for the diagnosis and monitoring of DKD. Various methods have been used to detect intact podocytes and podocyte-derived microvesicles in urine, including centrifugation, visualization, and molecular quantification. Quantification of podocyte-specific protein targets and messenger RNA levels can be performed by Western blotting or enzyme-linked immunosorbent assay and quantitative polymerase chain reaction, respectively. At present, many of these techniques are expensive and labor-intensive, all limiting their widespread use in routine clinical tests. While the potential of urinary podocyte markers for monitoring and risk stratification of DKD has been explored, systematic studies and external validation are lacking in the current literature. Standardization and automation of laboratory methods should be a priority for future research, and the added value of these methods to routine clinical tests should be defined.

Hypercholesterolemia-associated oxidative stress increases the formation of oxidized low-density lipoprotein (oxLDL), which can affect endothelial cell function and potentially contribute to renal dysfunction, as reflected by changes in urinary protein excretion. This study aimed to investigate the impact of exogenous oxLDL on urinary excretion of albumin and nephrin. LDL was isolated from a patient with familial hypercholesterolemia (FH) undergoing lipoprotein apheresis (LA) and was oxidized in vitro with Cu (II) ions. Biochemical markers of LDL oxidation, such as TBARS, conjugated dienes, and free ε-amino groups, were measured. Wistar rats were treated with a single intraperitoneal injection of PBS, LDL, or oxLDL (4 mg of protein/kg b.w.). Urine was collected one day before and two days after the injection. We measured blood lipid profiles, urinary protein excretion (specifically albumin and nephrin), and markers of systemic oxidative stress (8-OHdG and 8-iso-PGF2α). The results showed that injection of oxLDL increased urinary albumin excretion by approximately 28% (310 ± 27 μg/24 h vs. 396 ± 26 μg/24 h, p = 0.0003) but had no effect on nephrin excretion. Neither PBS nor LDL had any effect on urinary albumin or nephrin excretion. Additionally, oxLDL did not affect systemic oxidative stress. In conclusion, hypercholesterolemia may adversely affect renal function through oxidatively modified LDL, which interferes with the renal handling of albumin and leads to the development of albuminuria. [ABSTRACT FROM AUTHOR]

Steroid-resistant nephrotic syndrome (SRNS) is the second most frequent cause of chronic kidney disease before the age of 25 yr. Nephrin, encoded by NPHS1, localizes to the slit diaphragm of glomerular podocytes and is the predominant structural component of the glomerular filtration barrier. Biallelic variants in NPHS1 can cause congenital nephrotic syndrome of the Finnish type, for which, to date, no causative therapy is available. Recently, adeno-associated virus (AAV) vectors targeting the glomerular podocyte have been assessed as a means for gene replacement therapy. Here, we established quantitative and reproducible phenotyping of a published, conditional Nphs1 knockout mouse model (Nphs1tm1.1Pgarg/J and Nphs2-Creþ) in preparation for a gene replacement study using AAV vectors. Nphs1 knockout mice (Nphs1fl/fl Nphs2-Creþ) exhibited 1) a median survival rate of 18 days (range: from 9 to 43 days; males: 16.5 days and females: 20 days); 2) an average foot process (FP) density of 1.0 FP/lm compared with 2.0 FP/lm in controls and a mean filtration slit density of 2.64 lm/lm2 compared with 4.36 lm/lm2 in controls; 3) a high number of proximal tubular microcysts; 4) the development of proteinuria within the first week of life as evidenced by urine albumin-to-creatinine ratios; and 5) significantly reduced levels of serum albumin and elevated blood urea nitrogen and creatinine levels. For none of these phenotypes, significant differences between sexes in Nphs1 knockout mice were observed. We quantitatively characterized five different phenotypic features of congenital nephrotic syndrome in Nphs1fl/fl Nphs2-Creþ mice. Our results will facilitate future gene replacement therapy projects by allowing for sensitive detection of even subtle molecular effects. [ABSTRACT FROM AUTHOR]

Introduction. Congenital nephrotic syndrome (CNS) is a severe disease complicated by hemodynamic instability, infections, thrombosis, growth disorder and progressive renal failure leading to end-stage kidney disease within a few years. The mutations of NPHS1 encoding nephrin is the most common cause of the CNS. The aim of this paper was to present a patient with NPHS1 homozygous Ser350Pro missense mutation that unexpectedly caused a mild clinical course of CNS. Case outline. We present a female patient who was diagnosed with severe nephrotic syndrome at 2.5 months of age. While waiting for the result of the genetic analysis, she was treated unsuccessfully with corticosteroids and angiotensin converting inhibitor (ACEI) four weeks, and then under Cyclosporine A (CsA) and ACEI she achieved partial remission within three months. Initially, the milder clinical course was explained by the positive effect of CsA, but as partial remission persisted even after the discontinuation of this drug, it remains unclear what influenced the improvement of the clinical course of the disease. At the time of writing this paper, the patient was 10.9 years old with normal serum creatinine, normal blood pressure and non-nephrotic proteinuria. Conclusion. NPHS1 homozygous Ser350Pro missense mutation may be presented by a mild clinical course of CNS. Further studies are needed to clarify a more predictive CNS genotype/phenotype relationship.

Background: Acromegaly is a rare disorder caused by excessive growth hormone (GH) secreted from a pituitary tumor. High levels of GH and insulin growth factor-1 can lead to renal hypertrophy, as well as to diabetes mellitus and hypertension, which negatively impact kidney function. It is believed that high GH may also be involved in the onset of diabetic nephropathy, the main cause of end-stage kidney disease in developed countries. Material and methods: This case–control study was conducted on 23 acromegalic patients and on a control group represented by 21 healthy subjects. The following parameters were determined for all the subjects: serum creatinine, serum urea, estimated glomerular filtration rate (eGFR), urinary albumin/creatinine ratio (UACR), nephrin and kidney injury molecule 1 (KIM-1). Results: Patients with acromegaly showed higher levels of UACR and lower levels of eGFR as compared to healthy subjects. No significant correlations were found between clinical or biochemical parameters associated with acromegaly and nephrin or KIM-1. Conclusions: There was no glomerular or proximal tubular damage at the time of the study, as proven by the normal levels of the biomarkers nephrin and KIM-1. Studies including more patients with uncontrolled disease are needed to clarify the utility of nephrin and KIM-1 for the detection of early kidney involvement in acromegalic patients.

Nephrin is a transmembrane protein that maintains the slit diaphragm of renal podocyte. In chronic kidney disease (CKD), podocyte effacement causes damage to glomerular basement membrane barrier leading to proteinuria. Boerhavia diffusa, (BD), an Ayurveda herb, is used in treatment of various diseases particularly in relation to the urinary system. This study attempts to evaluate the effect of ethanolic extract of BD on the expression of nephrin in adenine induced CKD rats. CKD was induced in Wistar albino rats using adenine (600/mg/kg, orally for 10 days). CKD rats were treated with BD (400/mg/kg/) and pirfenidone (500/mg/kg) orally for 14 days. The kidneys were harvested from euthanized animals and processed for histopathology, electron microscopy and immunohistochemistry, gene and protein expression of nephrin. Diseased rats treated with BD and pirfenidone showed reduction in the thickening of renal basement membranes and reduced haziness in brush border of PCT and glomeruli. Nephrin gene and protein expressions were higher in BD and pirfenidone treated group when compared to the disease control group. The structural and functional damage brought on by adenine-induced nephrotoxicity was countered by protective action of BD by up regulating the expression of nephrin. Therefore, BD can be utilized as a nutraceutical for the prevention and treatment of CKD. [ABSTRACT FROM AUTHOR]

The most common viral infections causing gastroenteritis in children include rotavirus, norovirus, and the SARS-CoV-2. A typical clinical picture includes fever, vomiting, diarrhea, toxicosis and exicosis of varying severity. However, in 30—35% of cases, acute intestinal infections of viral etiology complicate of acute kidney injury (AKI), which significantly aggravates the course of the disease and affects the outcome of the disease. Currently used markers for the diagnosis of AKI are poor informative due to late detection of typical laboratory changes during the clinical picture's change. Currently, there are non-invasive biomarkers of AKI detected before changes in routine biochemical tests and can be used for early diagnosis of kidney damage. Using of these biomarkers in practice will develop of clinical and laboratory differential diagnostic criteria for early diagnosis, risk factors for the development of AKI in children with viral diarrhea of various agents, in order to start timely effective pathogenetic treatment and prevent serious complications.

Abstract Background Shenkang injection has been used clinically to lower creatinine levels. This study explored the mechanism of Shenkang injection on protecting kidney function from hyperglycemia-mediated damage. Methods This study utilized a STreptoZotocin (STZ)-induced rat model of diabetes. In total, 60 rats were randomized into either the control group (n = 15) injected with vehicle or treatment group (n = 45) injected with STZ to induce hyperglycemia. Eight weeks after diabetes onset, diabetic rats were further randomized to receive different treatments for 4 consecutive weeks, including vehicle (diabetic nephropathy group, n = 15), Shenkang (n = 15), or Valsartan (n = 15). At 12 weeks, a series of urine and blood measures were examined and damage to the kidney tissue was examined using histology. Expression of nephrin and transforming growth factor-β1 (TGF-β1) were characterized using immunohistochemistry and Western blot. Results Compared to the control group, rats in the diabetic nephropathy group showed significant kidney damage demonstrated by high kidneyindex, high levels of urinary albumin, albumin/creatinine ratio (ACR), blood urea nitrogen as well as histological evidence. Shenkang injection significantly improved kidney function in the diabetic rats by decreasing kidney index, ACR, and serum creatinine. Shenkang treatment also mitigated kidney damage, improved nephrin expression, and decreased TGF-β1 expression in the kidneys. Conclusions Shenkang treatment protected renal function in diabetic rats by increasing nephrin expression, which protects diabetic rats from hyperglycemia-mediated kidney damage.

Hypertensive nephropathy (HN) is characterized by kidney damage due to chronic high blood pressure. Podocytes play a crucial role in the pathogenesis of HN, thus, nephrin could be important in the early diagnosis of HN. The aim of the study was to investigate the association of urinary nephrin (u-nephrin) levels with clinical and laboratory characteristics in patients with HN and to test diagnostic relevance of u-nephrin as an early biomarker of HN. In this cross-sectional study, 114 subjects were recruited, 84 patients with chronic hypertension (CH) and 30 healthy controls. All patients with CH were classified according to the urinary microalbumin/creatinine ratio (UM/CR) and according to the chronic kidney disease (CKD) stage. Urine samples were collected to estimate the u-nephrin level by ELISA and to determine UM/CR. Blood samples were used for biochemical analyses. We found elevated u-nephrin in 78.3% of normoalbuminuric subjects with CH. The levels of u-nephrin increased gradually with the stage of CKD. ROC curve plotted for u-nephrin showed 89.7% sensitivity and 88.8% specificity, while UM/CR showed a sensitivity of 44.8% and specificity of 86.1% to detect HN in the early stage. It is concluded that u-nephrin can be useful as an early biomarker of HN.

Background Renoprotective effects of vitamin D analogues have been shown in several experimental and clinical studies, the exact mechanism of the therapeutic effectiveness of these analogues in Nephrotic syndrome remains unclear, and these are relatively few studies on potential treatment roles for vitamin D analogues in nephrotic-range proteinuria. ?ndicate similar efficacy of the vitamin D analogues calcitriol and paricalcitol in time-limited amelioration of proteinuria in nephrotic syndrome, yet suggest the likelihood of mechanisms other than direct upregulation of nephrin and podocin in podocytes underlie the renoprotective effects of vitamin D analogues. Objective To investigate the effect of vitamin D (Vit D) analogues calcitriol and paricalcitol on urinary protein/creatinine ratio (UPCR) and renal podocin and nephrin expression in a rat model of puromycin aminonucleoside (PAN)-induced nephrotic syndrome (NS). Methods A total of 28 male Wistar Albino rats were separated into 4 groups (n=7 for each) including CON [control; intraperitoneal (IP) saline injection], PAN (NS + IP saline injection), PAN-C (NS + IP 0.4 µg/kg/day calcitriol injection), and PAN-P (NS + IP 240 ng/kg/day paricalcitol injection). Nephrotic syndrome was induced via intravenous (IV) administration of 10mg/100gr PAN. The UPCR as well as histopathological, immuno-histochemical, and real time PCR analyses of kidney tissue specimens were recorded and analyzed among the 4 groups. Results Median UPCR (Day 4) was significantly lower in both the PAN-C [1.45 (range 1.20-1.80)] and PAN-P [1.40 (range 1.10-1.80)] groups than in the PAN group [2.15 (range 2.00-2.40)] (P

Congenital nephrotic syndrome (CNS) is a rare hereditary kidney disease that begins at birth or within the first three months of life. CNS is characterized by severe proteinuria, hypoalbuminemia, edema, and hyperlipidemia. It is primarily caused by gene mutations that result in damage to the glomerular filtration barrier. We wanted to present the clinical course of our four patients, one of whom was in spontaneous remission. In this study, we wanted to draw attention to the different clinical courses of patients with nephrin mutations. [ABSTRACT FROM AUTHOR]

The definition of acute kidney injury (AKI), despite improvements in criteria, continues to be based on the level of serum creatinine and urinary output that do not specifically indicate tubular function or injury, or glomerular function or injury that is not significant enough to warrant acute hospitalization of the patient. Finding novel biomarkers of AKI has become a major focus nowadays in nephrology to overcome the further complications of end stage renal disease (ESRD). Many compounds, such as KIM 1, IL 18, NGAL, uromodulin, calprotectin, vanin 1, galactin 3, platelet-derived growth factor (PDGF), urinary Na+/H+ exchanger isoform 3 (NHE3), retinol binding protein (RBP) and Cystatin C, are released from the renal tubules and thus any alterations in tubular function can be detected by measuring these parameters in urine. Additionally, glomerular injury can be detected by measuring immunoglobulin G, nephrin, podocalyxin, podocin, transferrin, netrin-1, pyruvate kinase M2, etc. in urine. These novel biomarkers will be useful for timing the initial insult and assessing the duration of AKI. According to available research, these biomarkers could be applied to assess the onset of AKI, distinguishing between kidney injury and dysfunction, directing the management of AKI, and enhancing disease diagnosis. Therefore, we intend to present recent developments in our understanding of significant biomarkers implicated in various aspects of renal damage. Numerous biomarkers are implicated in various pathophysiological processes that follow renal injury, and can improve prognosis and risk classification. [ABSTRACT FROM AUTHOR]

Abstract Diabetic nephropathy (DN) is a prevalent diabetic microvascular condition. It is the leading cause of kidney disease in the advanced stages. There is no currently effective treatment available. This research aimed to investigate the curative potentials of exosomes isolated from mesenchymal stem cells affecting DN. This study was performed on 70 male adult albino rats. Adult rats were randomized into seven groups: Group I: Negative control group, Group II: DN group, Group III: Balanites treated group, Group IV: MSCs treated group, Group V: Exosome treated group, Group VI: Balanites + MSCs treated group and Group VII: Balanites + exosome treated group. Following the trial period, blood and renal tissues were subjected to biochemical, gene expression analyses, and histopathological examinations. Results showed that MDA was substantially increased, whereas TAC was significantly decreased in the kidney in the DN group compared to normal health rats. Undesired elevated values of MDA levels and a decrease in TAC were substantially ameliorated in groups co-administered Balanites aegyptiacae with MSCs or exosomes compared to the DN group. A substantial elevation in TNF-α and substantially diminished concentration of IGF-1 were noticed in DN rats compared to normal health rats. Compared to the DN group, the co-administration of Balanites aegyptiacae with MSCs or exosomes substantially improved the undesirable elevated values of TNF-α and IGF-1. Furthermore, in the DN group, the mRNA expression of Vanin-1, Nephrin, and collagen IV was significantly higher than in normal healthy rats. Compared with DN rats, Vanin-1, Nephrin, and collagen IV Upregulation were substantially reduced in groups co-administered Balanites aegyptiacae with MSCs or exosomes. In DN rats, AQP1 expression was significantly lower than in normal healthy rats. Furthermore, the groups co-administered Balanites aegyptiacae with MSCs or exosomes demonstrated a substantial increase in AQP1 mRNA expression compared to DN rats.

Abstract Ischemia/reperfusion injury (I/R) is commonly related to acute kidney injury (AKI) and oxidative stress. Antioxidant agents are used to treat this condition. Lippia sidoides is a brazillian shrub with anti-inflammatory and anti-oxidative properties. Thus, the aim of this study is to evaluate the effect of Lippia sidoides ethanolic extract (LSEE) on in vivo and in vitro models of AKI induced by I/R. Male Wistar rats were submitted to unilateral nephrectomy and ischemia on contralateral kidney for 60 min via clamping followed by reperfusion for 48 h. They were divided into four groups: Sham, LSEE (sham-operated rats pre-treated with LSEE), I/R (rats submitted to ischemia) and I/R-LSEE (rats treated with LSEE before ischemia). Kidney tissues homogenates were used to determine stress parameters and nephrin expression. Plasma and urine samples were collected for biochemical analysis. I/R in vitro assays were evaluated by 3-(4,5-Dimethylthiazol-2-yl)-2,5-Diphenyltetrazolium Bromide (MTT) and flow cytometry assays in Rhesus Monkey Kidney Epithelial Cells (LLC-MK2). The LSEE treatment prevented biochemical and nephrin expression alterations, as well as oxidative stress parameters. In the in vitro assay, LSEE protected against cell death, reduced the reactive oxygen species and increased mitochondrial transmembrane potential. LSEE showed biotechnological potential for a new phytomedicine as a nephroprotective agent.

Sphingosine 1-phosphate (S1P) lyase (SPL, Sgpl1) is an ER-associated enzyme that irreversibly degrades the bioactive lipid, S1P, and thereby regulates multiple cellular functions attributed to S1P. Biallelic mutations in the human Sglp1 gene lead to a severe form of a particular steroid-resistant nephrotic syndrome, suggesting that the SPL is critically involved in maintaining the glomerular ultrafiltration barrier, which is mainly built by glomerular podocytes. In this study, we have investigated the molecular effects of SPL knockdown (kd) in human podocytes to better understand the mechanism underlying nephrotic syndrome in patients. A stable SPL-kd cell line of human podocytes was generated by the lentiviral shRNA transduction method and was characterized for reduced SPL mRNA and protein levels and increased S1P levels. This cell line was further studied for changes in those podocyte-specific proteins that are known to regulate the ultrafiltration barrier. We show here that SPL-kd leads to the downregulation of the nephrin protein and mRNA expression, as well as the Wilms tumor suppressor gene 1 (WT1), which is a key transcription factor regulating nephrin expression. Mechanistically, SPL-kd resulted in increased total cellular protein kinase C (PKC) activity, while the stable downregulation of PKCδ revealed increased nephrin expression. Furthermore, the pro-inflammatory cytokine, interleukin 6 (IL-6), also reduced WT1 and nephrin expression. In addition, IL-6 caused increased PKCδ Thr505 phosphorylation, suggesting enzyme activation. Altogether, these data demonstrate that nephrin is a critical factor downregulated by the loss of SPL, which may directly cause podocyte foot process effacement as observed in mice and humans, leading to albuminuria, a hallmark of nephrotic syndrome. Furthermore, our in vitro data suggest that PKCδ could represent a new possible pharmacological target for the treatment of a nephrotic syndrome induced by SPL mutations. [ABSTRACT FROM AUTHOR]

Podocyte injury leading to albuminuria is a characteristic feature of diabetic nephropathy (DN). Hyperglycemia and advanced glycation end products (AGEs) are major determinants of DN. However, the underlying mechanisms of podocyte injury remain poorly understood. The cytosolic protein TNFAIP2/M-Sec is required for tunneling nanotubes (TNTs) formation, which are membrane channels that transiently connect cells, allowing organelle transfer. Podocytes express TNFAIP2 and form TNTs, but the potential relevance of the TNFAIP2-TNT system in DN is unknown. We studied TNFAIP2 expression in both human and experimental DN and the renal effect of tnfaip2 deletion in streptozotocin-induced DN. Moreover, we explored the role of the TNFAIP2-TNT system in podocytes exposed to diabetes-related insults. TNFAIP2 was overexpressed by podocytes in both human and experimental DN and exposre of podocytes to high glucose and AGEs induced the TNFAIP2-TNT system. In diabetic mice, tnfaip2 deletion exacerbated albuminuria, renal function loss, podocyte injury, and mesangial expansion. Moreover, blockade of the autophagic flux due to lysosomal dysfunction was observed in diabetes-injured podocytes both in vitro and in vivo and exacerbated by tnfaip2 deletion. TNTs allowed autophagosome and lysosome exchange between podocytes, thereby ameliorating AGE-induced lysosomal dysfunction and apoptosis. This protective effect was abolished by tnfaip2 deletion, TNT inhibition, and donor cell lysosome damage. By contrast, Tnfaip2 overexpression enhanced TNT-mediated transfer and prevented AGE-induced autophagy and lysosome dysfunction and apoptosis. In conclusion, TNFAIP2 plays an important protective role in podocytes in the context of DN by allowing TNT-mediated autophagosome and lysosome exchange and may represent a novel druggable target. Abbreviations: AGEs: advanced glycation end products; AKT1: AKT serine/threonine kinase 1; AO: acridine orange; ALs: autolysosomes; APs: autophagosomes; BM: bone marrow; BSA: bovine serum albumin; CTSD: cathepsin D; DIC: differential interference contrast; DN: diabetic nephropathy; FSGS: focal segmental glomerulosclerosis; HG: high glucose; KO: knockout; LAMP1: lysosomal-associated membrane protein 1; LMP: lysosomal membrane permeabilization; MAP1LC3/LC3: microtubule-associated protein 1 light chain 3; PI3K: phosphoinositide 3-kinase; STZ: streptozotocin; TNF: tumor necrosis factor; TNFAIP2: tumor necrosis factor, alpha-induced protein 2; TNTs: tunneling nanotubes; WT: wild type. [ABSTRACT FROM AUTHOR]

Dent disease (DD1) is a rare tubulopathy caused by mutations in the CLCN5 gene. Glomerulosclerosis was recently reported in DD1 patients and ClC-5 protein was shown to be expressed in human podocytes. Nephrin and actin cytoskeleton play a key role for podocyte functions and podocyte endocytosis seems to be crucial for slit diaphragm regulation. The aim of this study was to analyze whether ClC-5 loss in podocytes might be a direct consequence of the glomerular damage in DD1 patients. Three DD1 kidney biopsies presenting focal global glomerulosclerosis and four control biopsies were analyzed by immunofluorescence (IF) for nephrin and podocalyxin, and by immunohistochemistry (IHC) for ClC-5. ClC-5 resulted as down-regulated in DD1 vs. control (CTRL) biopsies in both tubular and glomerular compartments (p < 0.01). A significant down-regulation of nephrin (p < 0.01) in DD1 vs. CTRL was demonstrated. CRISPR/Cas9 (Clustered Regularly Interspaced Short Palindromic Repeats/Caspase9) gene editing of CLCN5 in conditionally immortalized human podocytes was used to obtain clones with the stop codon mutation p.(R34Efs*14). We showed that ClC-5 and nephrin expression, analyzed by quantitative Reverse Transcription/Polymerase Chain Reaction (qRT/PCR) and In-Cell Western (ICW), was significantly downregulated in mutant clones compared to the wild type ones. In addition, F-actin staining with fluorescent phalloidin revealed actin derangements. Our results indicate that ClC-5 loss might alter podocyte function either through cytoskeleton disorganization or through impairment of nephrin recycling. [ABSTRACT FROM AUTHOR]

Chronic kidney diseases (CKD) caused by acute kidney injury (AKI) results rapid and reversible loss in renal function. A real-time, highly accurate, and sensitive acute kidney injury biomarker is urgently required in order to keep these patients alive and prevent end stage renal disease and related complications that include hypertension, fluid and electrolyte retention, metabolic acidosis, anemia, stroke etc. This study was designed to develop a specific and sensitive model for the early identification of renal damage in male albino rats. Using a single intraperitoneal dose of cisplatin (10 mg/kg body weight) to the rats, the various duration-dependent nephrotoxic activities were compared using multiple physiological, biochemical, genomic, and histopathological markers. We looked into when renal dysfunction would start occurring after receiving a single high dose of cisplatin while blood urea nitrogen (BUN) and serum creatinine (sCr) remained normal. Following a single cisplatin injection, various measurements were taken in plasma, urine, and/or kidney tissues of rats euthanized on days 1, 2, 3, 5, and 7. When the urine kidney injury molecule (KIM-1), interleukine 18 (IL-18), nephrin, neutrophil gelatinase-associated lipocalin (NGAL) and serum cystatin C (Cys C) levels are greatly raised on day 3 after cisplatin treatment, BUN and sCr levels remain normal. Nephrotoxicity of cisplatin is also indicated by the upregulated mRNA expression of KIM-1, IL-18, Cys C, and NGAL and downregulated expression of nephrin in kidney tissue at very initial stage. Protein expression of KIM-1, IL-18 and NGAL level of kidney tissues was upregulated indicated confirmatory results done by western blot. Utilising an array of kidney impairment indicators has emerged as an earlier, more effective, and more reliable technique to diagnose AKI when compared to the most sophisticated signs now available.

Introduction: Pre-eclampsia (PE) is characterized by new-onset hypertension and proteinuria. Damage of podocyte cells has been reported in pre-eclamptic women, thus podocyte specific proteins such as nephrin and podocalyxin could be useful biomarkers in PE.Aim: To investigate the role of urinary nephrin (u-nephrin) and urinary podocalyxin (u-PDX) levels in predicting PE in women with a high-risk pregnancy.Materials and methods: We included 101 pregnant women in this study and allocated them into three groups: group 1 included pregnant women at high risk of developing PE (n=41), group 2 - pregnant women with PE (n=30), and group 3 was the controls including healthy pregnant women (n=30). The inclusion criteria for women with PE were de novo hypertension >140/90 mm Hg, proteinuria >300 mg/24 hours, and presence of edema after 20 weeks of gestation, while the exclusion criteria were a history of renal diseases and pregnant women younger than 18. Inclusion criteria for the group of women with a high-risk pregnancy was gestational week >15, a history of PE in a previous pregnancy, pre-existing diabetes type 1 or 2, pre-existing hypertension, multiple gestations, prior placental abruption, obesity women, nulliparity, maternal age >35 years, and a family history of PE. The study was conducted from March 2016 to May 2017 in the Medical Faculty at the Institute of Medical and Experimental Biochemistry in Skopje. Urine samples were used to measure the nephrin and podocalyxin levels using immunoenzyme assay, creatinine and microalbumin. Blood samples were collected for biochemical analyses.Results: U-nephrin levels were elevated in 96.7% of women with PE, and 73% of women with a high-risk pregnancy. U-PDX levels were elevated in 63% of the women with PE and 100% of the women with a high-risk pregnancy. U-nephrin and u-PDX levels were significantly increased in women with a high-risk pregnancy and women with PE compared with a control group (p

Background Renoprotective effects of vitamin D analogues have been shown in several experimental and clinical studies. The exact mechanism of the therapeutic effectiveness of these analogues in nephrotic syndrome remains unclear, and these are relatively few studies on potential treatment roles for vitamin D analogues in nephrotic-range proteinuria. İndicate similar efficacy of the vitamin D analogues calcitriol and paricalcitol in time-limited amelioration of proteinuria in nephrotic syndrome, yet suggest the likelihood of mechanisms other than direct upregulation of nephrin and podocin in podocytes underlie the renoprotective effects of vitamin D analogues. Objective To investigate the effect of vitamin D analogues calcitriol and paricalcitol on urinary protein/creatinine ratio (UPCR) and renal podocin and nephrin expression in a rat model of puromycin aminonucleoside (PAN)-induced nephrotic syndrome (NS). Methods A total of 28 male Wistar Albino rats were separated into 4 groups (n=7 for each) including CON [control; intraperitoneal (IP) saline injection], PAN (NS + IP saline injection), PAN-C (NS + IP 0.4 µg/kg/day calcitriol injection), and PAN-P (NS + IP 240 ng/kg/day paricalcitol injection). Nephrotic syndrome was induced via intravenous (IV) administration of 10mg/100gr PAN. The UPCR as well as histopathological, immuno-histochemical, and real time PCR analyses of kidney tissue specimens were recorded and analyzed among the 4 groups. Results Median UPCR (Day 4) was significantly lower in both the PAN-C [1.45 (range 1.20-1.80)] and PAN-P [1.40 (range 1.10- 1.80)] groups than in the PAN group [2.15 (range 2.00-2.40)] (P<0.01 for each). The PAN group had significantly higher mean UPCR than the CON group [1.75 (range 1.40-2.00); P<0.05]. No significant difference in UPCR was noted between groups on Day 7. Median podocin mRNA expression was significantly higher in the PAN-P group compared to the PAN group [22.55 (range 22.42-23.02) vs. 22.06 (range 21.81-22.06), respectively; (P<0.01)]. Conclusion Seven-day calcitriol and paricalcitol supplementation in a rat model of PAN-induced nephrotic syndrome have similar efficacy, in terms of temporary amelioration of proteinuria. [ABSTRACT FROM AUTHOR]

Abstract Background: This study examined the effect of prenatal and early postnatal ethanol exposure on the structural, functional, and molecular alterations of rat’s offspring kidney on postnatal days 21 and 90. Methods: Pregnant rats on gestation day 7 were divided into the two groups, namely control and ethanol groups. Rats in the ethanol group received ethanol (4.5 g/kg B.W) from gestation day 7 throughout lactation. Nephrin, podocin, vascular endothelial growth factor receptors (VEGFRs) 1 and 2 gene expression were measured by RT-PCR technique. The MMP2 and MMP9 levels in the kidney tissue and plasma cystatin C level were measured by ELISA method. Results: The results revealed a significant alteration in mRNA expression of nephrin, podocin, and VEGFR, as well as MMPs amounts in the kidneys of the offspring. Cystatin C level, the ratio of cystatin C/serum creatinine, serum creatinine, and urine urea showed a significant increase, but urine creatinine and GFR showed a significant decrease in the offsprings of the ethanol group compared to the control group. Histopathological changes such as fibrosis, kidney cells proliferation, leukocytes infiltration, and vacuolization have also seen in the kidney of the offsprings after 21 and 90 days from birth. Conclusion: Taken together, these results provide evidence that pre and early postnatal ethanol exposure renal toxicity is in part associated with alteration of nephrin, podocin, and VEGFRs genes expression, as well as MMPs amount changes. Furthermore, it was found that these molecular alterations were triggered by inflammatory reactions manifested by fibrosis, proliferation, and polymorphonuclear(PMN) leukocytes infiltration. [ABSTRACT FROM AUTHOR]

Nephrotic syndrome (NS) is a disease characterized by proteinuria and subsequent hypoalbuminemia, hyperlipidemia and edema due to the defective renal glomerular filtration barrier (GFB). Mutations of NPHS1, encoding NEPHRIN, a podocyte protein essential for normal GFB, cause congenital nephrotic syndrome (CNS) of the Finnish type (CNF), which accounts for about 50% of CNS cases. We generated zebrafish nphs1 mutants by using CRISPR/Cas9. These mutants completely lack nephrin proteins in podocytes and develop progressive peri-orbital and whole-body edema after 5 days post fertilization. Ultra-structurally, loss of nephrin results in absence of slit-diaphragms and progressive foot process effacement in zebrafish pronephric glomeruli, similar to the pathological changes in human CNF patients. Interestingly, some nphs1 mutants are viable to adulthood despite ultra-structural defects in renal glomeruli. Using a reporter line Tg (l-fabp:VDBP-GFP) expressing GFP-tagged vitamin-D-binding protein in the blood plasma, we observed a reduction of intravascular GFP fluorescence in the nphs1 mutants, a hypoalbuminemia-like phenotype. In addition, we detected excretion of GFP by the nphs1 mutants, reminiscent of proteinuria. Therefore, we have demonstrated that the nphs1 mutant zebrafish recapitulate the human NS phenotypes and provide a novel and relevant animal model useful for screening therapeutical agents for this disease.

Urolithins are bioactive compounds generated in human and animal intestines because of the bacterial metabolism of dietary ellagitannins (and their constituent, ellagic acid). Due to their multidirectional effects, including anti-inflammatory, antioxidant, anti-cancer, neuroprotective, and antiglycative properties, urolithins are potential novel therapeutic agents. In this study, while considering the future possibility of using urolithins to improve podocyte function in diabetes, we assessed the results of exposing mouse podocytes cultured in normal (NG, 5.5 mM) and high (HG, 25 mM) glucose concentrations to urolithin A (UA) and urolithin B (UB). Podocytes metabolized UA to form glucuronides in a time-dependent manner; however, in HG conditions, the metabolism was lower than in NG conditions. In HG milieu, UA improved podocyte viability more efficiently than UB and reduced the reactive oxygen species level. Both types of urolithins showed cytotoxic activity at high (100 µM) concentration. The UA upregulated total and surface nephrin expression, which was paralleled by enhanced nephrin internalization. Regulation of nephrin turnover was independent of ambient glucose concentration. We conclude that UA affects podocytes in different metabolic and functional aspects. With respect to its pro-survival effects in HG-induced toxicity, UA could be considered as a potent therapeutic candidate against diabetic podocytopathy. [ABSTRACT FROM AUTHOR]

Both mTOR signaling and autophagy are important modulators of podocyte homeostasis, regeneration, and aging and have been implicated in glomerular diseases. However, the mechanistic role of these pathways for the glomerular filtration barrier remains poorly understood. We used Drosophila nephrocytes as an established podocyte model and found that inhibition of mTOR signaling resulted in increased spacing between slit diaphragms. Gain-of-function of mTOR signaling did not affect spacing, suggesting that additional cues limit the maximal slit diaphragm density. Interestingly, both activation and inhibition of mTOR signaling led to decreased nephrocyte function, indicating that a fine balance of signaling activity is needed for proper function. Furthermore, mTOR positively controlled cell size, survival, and the extent of the subcortical actin network. We also showed that basal autophagy in nephrocytes is required for survival and limits the expression of the sns (nephrin) but does not directly affect slit diaphragm formation or endocytic activity. However, using a genetic rescue approach, we demonstrated that excessive, mTOR-dependent autophagy is primarily responsible for slit diaphragm misspacing. In conclusion, we established this invertebrate podocyte model for mechanistic studies on the role of mTOR signaling and autophagy, and we discovered a direct mTOR/autophagy-dependent regulation of the slit diaphragm architecture. [ABSTRACT FROM AUTHOR]

Objective: To explore the genetic bias in a Chinese family suspected of having congenital nephrotic syndrome of the Finnish type (CNF). Case report: We developed a prenatal genetic diagnosis in a Chinese family with CNF. A single heterozygous mutation (c.3213delG) was found in the foetus IId and we presumed that it was an asymptomatic carrier of the normal phenotype. Additionally, two compound heterozygous variants (c.3213delG and c.3478C > T) were discovered in the foetus IIe, which were inherited from the mother and father, respectively. We performed further pathological examinations after medical abortion. Kidney histopathology and immunofluorescence results were similar to those reported in previous studies. Conclusion: Prenatal genetic diagnosis of CNF still requires further research to explore the pathogenicity of suspected mutations.

The kidneys generate about 180 l of primary urine per day by filtration of plasma. An essential part of the filtration barrier is the slit diaphragm, a multiprotein complex containing nephrin as major component. Filter dysfunction typically manifests with proteinuria and mutations in endocytosis regulating genes were discovered as causes of proteinuria. However, it is unclear how endocytosis regulates the slit diaphragm and how the filtration barrier is maintained without either protein leakage or filter clogging. Here, we study nephrin dynamics in podocyte-like nephrocytes of Drosophila and show that selective endocytosis either by dynamin- or flotillin-mediated pathways regulates a stable yet highly dynamic architecture. Short-term manipulation of endocytic functions indicates that dynamin-mediated endocytosis of ectopic nephrin restricts slit diaphragm formation spatially while flotillin-mediated turnover of nephrin within the slit diaphragm is needed to maintain filter permeability by shedding of molecules bound to nephrin in endosomes. Since slit diaphragms cannot be studied in vitro and are poorly accessible in mouse models, this is the first analysis of their dynamics within the slit diaphragm multiprotein complex. Identification of the mechanisms of slit diaphragm maintenance will help to develop novel therapies for proteinuric renal diseases that are frequently limited to symptomatic treatment.

Objectives: To investigate the effects of a glucagon-like peptide-1 receptor agonist (GLP-1RA) liraglutide on podocytes, inflammation, and oxidative stress in patients with diabetic nephropathy (DN). Methods: Eighty-four DN patients treated by the department of endocrinology of the Affiliated Hospital of Hebei University during December 2017 and March 2019 were randomly assigned to a control group and a treatment group (n=42, respectively), with the control group prescribed with conventional DN medications and the treatment group receiving liraglutide treatment in addition to the conventional therapy. The course of treatment lasted for 12 weeks. hemoglobin A1c (HbA1C), body mass index (BMI), total cholesterol (TC), triglyceride (TG), urinary albumin excretion rate (UAER), urine podocalyxin (PCX), urine nephrin, as well as inflammation and oxidative stress markers such as tumor necrosis factor a (TNF-a), monocyte chemotactic protein-1 (MCP-1), glutathione peroxidase (GSH-Px), and malondialdehyde (MDA) were measured pre- and post-treatment for intergroup comparison. Results: After 12 weeks of treatment, HbA1C, BMI, TC, and TG in both groups were reduced in comparison with the pre-treatment levels, with the levels in the treatment group lower than in the control group (p<0.05); reduced levels of UAER, PCX, and nephrin were detected in the two groups, with the treatment group exhibiting a significant reduction in these markers compared with the control group (p<0.05); the 12-week treatment led to decreases in the TNF-a, MCP-1, and MDA levels in both groups, with the decline in the treatment group exceeding that in the control group, whereas both groups had an increased level of GSH-Px, with the level in the treatment group higher than that in the control group, and the differences were statistically significant (p<0.05, respectively). Conclusions: Liraglutide protects the kidneys and improves DN by inhibiting inflammation and oxidative stress, reducing urinary albumin excretion and podocyte damage and supporting renal function in addition to its hypoglycemic properties. [ABSTRACT FROM AUTHOR]

Chronic hyperglycemia, as in diabetes mellitus, may cause glomerular damage with microalbuminuria as an early sign. Noteworthy, even acute hyperglycemia can increase glomerular permeability before structural damage of the glomerular filter can be detected. Despite intensive research, specific antiproteinuric therapy is not available so far. Thus, a deeper understanding of the molecular mechanisms of albuminuria is desirable. P38 MAPK signaling is involved in the development of hyperglycemia-induced albuminuria. However, the mechanism of increased p38 MAPK activity leading to increased permeability and albuminuria remained unclear. Recently, we demonstrated that acute hyperglycemia triggers endocytosis of nephrin, the key molecule of the slit diaphragm, and induces albuminuria. Here, we identify p38 MAPK as a pivotal regulator of hyperglycemia-induced nephrin endocytosis. Activated p38 MAPK phosphorylates the nephrin c-terminus at serine 1146, facilitating the interaction of PKCα with nephrin. PKCα phosphorylates nephrin at threonine residues 1120 and 1125, mediating the binding of β-arrestin2 to nephrin. β-arrestin2 triggers endocytosis of nephrin by coupling it to the endocytic machinery, leading to increased glomerular permeability. Pharmacological inhibition of p38 MAPK preserves nephrin surface expression and significantly attenuates albuminuria. Key messages: Acute hyperglycemia triggers endocytosis of nephrin. Activated p38 MAPK phosphorylates the nephrin c-terminus at serine 1146, facilitating the interaction of PKCα with nephrin. PKCα phosphorylates nephrin at threonine residues 1120 and 1125, mediating the binding of β-arrestin2 to nephrin. β-arrestin2 triggers endocytosis of nephrin by coupling it to the endocytic machinery, leading to a leaky glomerular filter. Pharmacological inhibition of p38 MAPK preserves nephrin surface expression and significantly attenuates albuminuria under hyperglycemic conditions. [ABSTRACT FROM AUTHOR]

The aim of this study was to explore the effect of rituximab-assisted prednisone and cyclophosphamide on the treatment of idiopathic membranous nephropathy (IMN) and its influence on serum levels of nephrin and B-cell activation factor belonging to the TNF family (BAFF). For this purpose, a prospective randomized controlled study method was designed for this study. 92 patients with IMN in our hospital from December 2015 to December 2017 were divided into study group (n=46) and control group (n=46) based on a computer-generated random number table. On the basis of conventional treatment, the control group was given prednisone and cyclophosphamide treatment, and the study group was given rituximab-assisted prednisone and cyclophosphamide treatment, both of which were treated for 6 months. The efficacy, adverse reactions, and recurrence rates of 1 and 2 years after treatment, clinical symptom scores and renal function indices such as urine protein quantification (Upro), blood creatinine (Scr), urea nitrogen (BUN)), serum albumin (ALB), nephrin, and BAFF levels before treatment, 3 months after treatment, and 6 months after treatment were compared between the 2 groups. Results showed that after treatment, the total effective rate of the study group was 93.48% higher than that of the control group 76.09% (P<0.05). The clinical symptom scores of the two groups were lower than those before treatment, and the score of study group was lower than that of the control group after 3 and 6 months of treatment (P<0.05). The 24h levels of Upro, serum Scr, BUN, and BAFF after 3 months and 6 months of treatment in the two groups were lower than those before treatment. The levels of the study group were lower than those of the control group. The serum ALB and nephrin levels were higher than those before treatment. The levels of the study group were higher than those of the control group (P<0.05). The two-year recurrence rate of the study group was 9.09% lower than that of the control group 25.00% (P<0.05). There was no significant difference in the incidence of adverse reactions between the two groups (P>0.05). To conclude, the application of rituximab-assisted prednisone and cyclophosphamide in the treatment of IMN can improve serum nephrin and BAFF levels, reduce clinical symptoms, improve renal function and curative effect, and reduce recurrence rate, and is safe. [ABSTRACT FROM AUTHOR]

Glomerular podocytes build, with their intercellular junctions, part of the kidney filter. The podocyte cell adhesion protein, nephrin, is essential for developing and maintaining slit diaphragms as functional loss in humans results in heavy proteinuria. Nephrin expression and function are also altered in many adult-onset glomerulopathies. Nephrin signals from the slit diaphragm to the actin cytoskeleton and integrin β1 at focal adhesions by recruiting Crk family proteins, which can interact with the Rap guanine nucleotide exchange factor 1 C3G. As Rap1 activity affects focal adhesion formation, we hypothesize that nephrin signals via Rap1 to integrin β. To address this issue, we combined Drosophila in vivo and mammalian cell culture experiments. We find that Rap1 is necessary for correct targeting of integrin β to focal adhesions in Drosophila nephrocytes, which also form slit diaphragm-like structures. In the fly, the Rap1 activity is important for signaling of the nephrin ortholog to integrin β, as well as for nephrin-dependent slit diaphragm integrity. We show by genetic interaction experiments that Rap1 functions downstream of nephrin signaling to integrin β and downstream of nephrin signaling necessary for slit diaphragm integrity. Similarly, in human podocyte culture, nephrin activation results in increased activation of Rap1. Thus, Rap1 is necessary for downstream signal transduction of nephrin to integrin β.

Serum and glucocorticoid-inducible kinase 3 (SGK3) is involved in maintaining podocyte function by regulating the protein levels of podocin and CD2-associated protein. Nephrin is also one of the slit diaphragm proteins of podocytes, but whether SGK3 participates in podocyte injury by regulating the levels of nephrin remains unclear. In this study, we focused on whether SGK3 affects nephrin levels and the mechanisms involved in the same. In the kidneys of adriamycin (ADR)-induced podocyte injury mouse model, the protein levels of SGK3 and nephrin were significantly decreased. Furthermore, the expression of SGK3 was negatively correlated with the output of proteinuria, and positively correlated with the levels of nephrin. In ADR-treated conditionally immortalized mouse podocyte cells (MPCs), the protein levels of nephrin and SGK3 were inhibited, while the constitutive expression of SGK3 reversed the ADR-induced decline in nephrin protein levels. Furthermore, ADR treatment or SGK3 inactivation enhanced the ubiquitin-proteasome degradation of nephrin in MPCs, and dramatically activated downstream effector proteins of SGK3, neural precursor cells expressing developmentally downregulated protein 4 subtype 2 (Nedd4-2) and glycogen synthase kinase-3 β (GSK3β). Similarly, Nedd4-2 or GSK3β overexpression resulted in increased activity of Nedd4-2 or GSK3β, and significantly downregulated nephrin levels. Interestingly, ubiquitin-mediated protein degradation of nephrin was regulated by Nedd4-2, rather than by GSK3β. In summary, SGK3 inactivation downregulated the levels of nephrin by increasing Nedd4-2 and GSK3β activity in ADR-induced podocyte injury model; in particular, the SGK3/Nedd4-2 signaling pathway was found to be involved in ubiquitin-mediated proteasome degradation of nephrin. [ABSTRACT FROM AUTHOR]

Aim The study explored the beneficial effects of repeated episodes of whole body hypoxic perconditioning (WHPC) on preeclampsia (PE)-like symptoms in rats. Material and Methods PE was induced by administration of L-NAME (75 mg/kg) and WHPC was performed by exposing rats to low O2 (8%) and normal O2 of 10 min each in four alternate cycles. Results L-NAME induced PE like symptoms in rats along with a decrease in the cystathionine-β-synthase (CBS) activity in the placental tissue, plasma levels of H2S and NO metabolites in pregnant rats. Two (GD9, GD14) and three episodes (GD9, GD14 and GD18) of WHPC improved PE-like symptoms with an increase in CBS activity and H2S levels. CBS inhibitor, amino-oxyacetic acid abolished the beneficial effects of three episodes of WHPC; while H2S donor, 4-methylbenzenecarbothioamide, 4-MBC attenuated PE-like symptoms. Conclusion WHPC attenuates L-NAME-induced PE-like symptoms due to increase in CBS activity and H2S-production.

Amaç: Bu çalışmada glomerül yapısındaki nefrin ve hipoksi indüklenebilir faktör-1alfa ekspresyonları aracılığıyla karbontetraklorid (CCl4) toksisitesi sonrası L-karnitin’in etkilerinin gösterilmesini amaçladık. Gereç ve Yöntem: 40 adet Sprague dawley erkek sıçan 5 gruba (n=8) ayrıldı. Grup I: Kontrol grubu; 0.2 ml zeytinyağı intraperitoneal (ip) haftada 2 kez, Grup II: L-karnitin grubu; 200 mg/kg L-karnitin (ip) haftada 2 kez, Grup III: CCl4 group; 0.2 ml CCl4 (ip) haftada 2 kez 6 hafta boyunca, Grup IV: L-karnitin + CCl4 grubu, haftada 2 kez CCl4 uygulamasından önce 200 mg/kg ip L-karnitin, Grup V: CCl4 + L-karnitin grubu, haftada 2 kez CCl4 uygulamasından 1 saat sonra 200 mg/kg ip L-karnitin. Böbrek doku kesitlerine nefrin ve HIF-1α ekspresyonunu göstermek için immunohistokimya boyama uygulandı. Proteinlerin ekspresyon yoğunlukları ImageJ programında ölçüldü.Bulgular: Nefrin ekspresyonu diğer gruplar ile kıyaslandığında Grup III’de anlamlı olarak arttı. HIF-1α ekspresyonu yalnızca Grup I ve Grup III arasında anlamlı şekilde arttı. Proteinlerin ekspresyon yoğunlukları L-karnitin-tedavili gruplarda kontrol grubuna benzerdi.Sonuç: L-karnitin böbrek glomerulusunda CCl4 toksisitesine karşı hem koruyucu hem tedavi edici etkilere sahiptir.

Background: Diabetic nephropathy (DN) is a leading cause of end-stage renal disease. Progressive damage and decline in the number of podocytes often occur in the early stages of DN. Thus, nephrin as a podocyte-specific protein may be regarded as a potential biomarker of early detection of DN. The aim of this study is to determine whether urinary nephrin is an earlier marker in DN than microalbuminuria and to test the significance of urinary nephrin as a marker for early detection of DN. Methods: Our cross-sectional study included 90 patients with type 2 diabetes mellitus (T2DM), 30 patients with diagnosed DN and 60 patients without diagnosed DN. As a control group, we used 30 healthy subjects. All patients with T2DM were classified into three subgroups according to urinary microalbumin/creatinine ratio (UMCR): normoalbuminuric, microalbuminuric and macroalbuminuric patients. Nephrin in urine was measured by immunoenzyme assay, microalbumin with turbidimetric and creatinine with the photometric method. In blood sera, we measured a few standard biochemical parameters. Results: Nephrinuria was found to be present in 100% of patients with T2DM and macroalbuminuria, in 88% with microalbuminuria, as well as 82% of patients with T2DM and normoalbuminuria. A concentration of urinary nephrin was significantly increased in all groups of subjects with T2DM compared to the control group (p

Serum and glucocorticoid-inducible kinase 3 (SGK3) is involved in maintaining podocyte function by regulating the protein levels of podocin and CD2-associated protein. Nephrin is also one of the slit diaphragm proteins of podocytes, but whether SGK3 participates in podocyte injury by regulating the levels of nephrin remains unclear. In this study, we focused on whether SGK3 affects nephrin levels and the mechanisms involved in the same. In the kidneys of adriamycin (ADR)-induced podocyte injury mouse model, the protein levels of SGK3 and nephrin were significantly decreased. Furthermore, the expression of SGK3 was negatively correlated with the output of proteinuria, and positively correlated with the levels of nephrin. In ADR-treated conditionally immortalized mouse podocyte cells (MPCs), the protein levels of nephrin and SGK3 were inhibited, while the constitutive expression of SGK3 reversed the ADR-induced decline in nephrin protein levels. Furthermore, ADR treatment or SGK3 inactivation enhanced the ubiquitin-proteasome degradation of nephrin in MPCs, and dramatically activated downstream effector proteins of SGK3, neural precursor cells expressing developmentally downregulated protein 4 subtype 2 (Nedd4-2) and glycogen synthase kinase-3 β (GSK3β). Similarly, Nedd4-2 or GSK3β overexpression resulted in increased activity of Nedd4-2 or GSK3β, and significantly downregulated nephrin levels. Interestingly, ubiquitin-mediated protein degradation of nephrin was regulated by Nedd4-2, rather than by GSK3β. In summary, SGK3 inactivation downregulated the levels of nephrin by increasing Nedd4-2 and GSK3β activity in ADR-induced podocyte injury model; in particular, the SGK3/Nedd4-2 signaling pathway was found to be involved in ubiquitin-mediated proteasome degradation of nephrin.

Abstract Canonical transient receptor potential‐6 (TRPC6) channels have been implicated in the progression of several forms of kidney disease (1). While there is strong evidence that glomerular TRPC6 channels are dysregulated in diabetic nephropathy (DN), there is no consensus as to whether deletion or inactivation of TRPC6 is protective in animal models of DN. A previous study in Dahl salt‐sensitive rats suggests that TRPC6 knockout has a modest protective effect in streptozotocin (STZ)‐induced DN (2). In the present study, we examined whether inactivation of TRPC6 channels by CRISPR/Cas9 editing (Trpc6del/del rats) affects progression of STZ‐induced DN in Sprague‐Dawley rats. Wild‐type littermates (Trpc6wt/wt rats) were used as controls. We observed that a single injection of STZ resulted in severe hyperglycemia that was sustained over a 10‐week period, accompanied by a marked reduction in circulating C‐peptide, dyslipidemia, and failure to gain weight compared to vehicle‐treated animals. Those effects were equally severe in Trpc6wt/wt and Trpc6del/del rats. STZ treatment resulted in increased urine albumin excretion at 4, 8, and 10 weeks after injection, and this effect was equally severe in Trpc6wt/wt and Trpc6del/del rats. TRPC6 inactivation had no effect on blood urea nitrogen (BUN), plasma creatinine concentration, urine nephrin excretion, or kidney weight:body weight ratio measured 10 weeks after STZ injection. STZ treatment evoked modest and equivalent mesangial expansion in Trpc6wt/wt and Trpc6del/del rats. In summary, we observed no protective effect of TRPC6 inactivation on STZ‐induced DN in rats on the Sprague‐Dawley background.

The definition of acute kidney injury (AKI), despite improvements in criteria, continues to be based on the level of serum creatinine and urinary output that do not specifically indicate tubular function or injury, or glomerular function or injury that is not significant enough to warrant acute hospitalization of the patient. Finding novel biomarkers of AKI has become a major focus nowadays in nephrology to overcome the further complications of end stage renal disease (ESRD). Many compounds, such as KIM 1, IL 18, NGAL, uromodulin, calprotectin, vanin 1, galactin 3, platelet-derived growth factor (PDGF), urinary Na+/H+ exchanger isoform 3 (NHE3), retinol binding protein (RBP) and Cystatin C, are released from the renal tubules and thus any alterations in tubular function can be detected by measuring these parameters in urine. Additionally, glomerular injury can be detected by measuring immunoglobulin G, nephrin, podocalyxin, podocin, transferrin, netrin-1, pyruvate kinase M2, etc. in urine. These novel biomarkers will be useful for timing the initial insult and assessing the duration of AKI. According to available research, these biomarkers could be applied to assess the onset of AKI, distinguishing between kidney injury and dysfunction, directing the management of AKI, and enhancing disease diagnosis. Therefore, we intend to present recent developments in our understanding of significant biomarkers implicated in various aspects of renal damage. Numerous biomarkers are implicated in various pathophysiological processes that follow renal injury, and can improve prognosis and risk classification.

Background: Diabetic kidney disease (DKD) is the most common and deranging microvascular complication of diabetes mellitus (DM). Podocytopathy is a key component of glomerular damage in DKD. Micro RNA-21 (miRNA-21) is an epigenetic regulator that plays a role in podocyte damage; however, the results of previous studies have not resolved the controversy about the role of miRNA-21 in the pathogenesis of DKD., Objective: The objective was to investigate the correlation between miRNA-21 levels and urinary nephrin, podocin, and urinary albumin-creatinine ratio (UACR) in patients with type 2 DM and albuminuria., Design: This is a cross-sectional study., Setting: This study was carried out in internal medicine outpatient clinic of Cipto Mangunkusumo Hospital Jakarta, Indonesia., Patients: This study consisted of 42 adults with type 2 DM and albuminuria., Measurements: The measurements include (1) Serum miRNA-21; (2) urinary podocin, nephrin, and albumin-creatinine ratio; and (3) serum miRNA-21 correlated to urinary podocin, nephrin, and albumin-creatinine ratio., Methods: The Spearman bivariate analysis to assess the correlation of miRNA-21 with nephrin, podocin, and UACR., Results: The mean relative expression of miRNA-21 was 0.069 (0.024), the median for nephrin, podocin, and UACR was 35.5 (15.75-51.25) ng/mL, 0.516 (0.442-0.545) ng/mL, and 150 (94.56-335.75) ng/mL, respectively. A correlation between miRNA-21 and nephrin was observed (r = 0.598; P < .0001). There was a correlation between miRNA-21 and UACR (r = 0.604; P < .0001). No correlation was found between miRNA-21 and podocin., Limitations: A lack of non-DM and non-albuminuric control population and small sample size. We could not exclude concurrent disease, and all other potential confounding variables, particularly those related to inflammation., Conclusions: The miRNA-21 can be considered an early biomarker for podocytopathy and albuminuria in DM, highlighting its potential for early diagnostic and therapeutic interventions. Further research is required to confirm these findings and explore their clinical applications, which could significantly alter management strategies for DKD., Competing Interests: The author(s) declared no potential conflicts of interest with respect to the research, authorship, and/or publication of this article., (© The Author(s) 2024.)

Modified Huangqi Chifeng decoction (MHCD) has been used to reduce proteinuria in immunoglobulin A nephropathy (IgAN) for many years. Previously, we have demonstrated its protective role in glomerular mesangial cells. Podocyte injury, another key factor associated with proteinuria in IgAN, has also attracted increasing attention. However, whether MHCD can reduce proteinuria by protecting podocytes remains unclear. The present study aimed to investigate the protective effects of MHCD against podocyte injury in a rat model of IgAN. To establish the IgAN model, rats were administered bovine serum albumin, carbon tetrachloride, and lipopolysaccharide. MHCD in three doses or telmisartan was administered once daily for 8 weeks (n = 10 rats/group). Rats with IgAN developed proteinuria at week 6, which worsened over time until drug intervention. After drug intervention, MHCD reduced proteinuria and had no effect on liver and kidney function. Furthermore, MHCD alleviated renal pathological lesions, hyperplasia of mesangial cells, mesangial matrix expansion, and podocyte foot process fusion. Western blot analysis revealed that MHCD increased the expression of the podocyte-associated proteins nephrin and podocalyxin. Additionally, we stained podocyte nuclei with an antibody for Wilms’ tumor protein one and found that MHCD increased the podocyte number in rats with IgAN. In conclusion, these results demonstrate that MHCD attenuates proteinuria by reducing podocyte injury.

Modified Huangqi Chifeng decoction (MHCD) has been used to reduce proteinuria in immunoglobulin A nephropathy (IgAN) for many years. Previously, we have demonstrated its protective role in glomerular mesangial cells. Podocyte injury, another key factor associated with proteinuria in IgAN, has also attracted increasing attention. However, whether MHCD can reduce proteinuria by protecting podocytes remains unclear. The present study aimed to investigate the protective effects of MHCD against podocyte injury in a rat model of IgAN. To establish the IgAN model, rats were administered bovine serum albumin, carbon tetrachloride, and lipopolysaccharide. MHCD in three doses or telmisartan was administered once daily for 8 weeks (n = 10 rats/group). Rats with IgAN developed proteinuria at week 6, which worsened over time until drug intervention. After drug intervention, MHCD reduced proteinuria and had no effect on liver and kidney function. Furthermore, MHCD alleviated renal pathological lesions, hyperplasia of mesangial cells, mesangial matrix expansion, and podocyte foot process fusion. Western blot analysis revealed that MHCD increased the expression of the podocyte-associated proteins nephrin and podocalyxin. Additionally, we stained podocyte nuclei with an antibody for Wilms' tumor protein one and found that MHCD increased the podocyte number in rats with IgAN. In conclusion, these results demonstrate that MHCD attenuates proteinuria by reducing podocyte injury. [ABSTRACT FROM AUTHOR]

Nur Samsu,1 Setyawati Soeharto,2 Muhaimin Rifai,3 Achmad Rudijanto41Department of Internal Medicine, Division of Nephrology and Hypertension, Faculty of Medicine; 2Department of Pharmacology, Faculty of Medicine; 3Department of Biology, Faculty of Mathematics and Sciences; 4Department of Internal Medicine, Division of Endocrinology and Metabolic, Faculty of Medicine, Universitas Brawijaya, Malang, IndonesiaCorrespondence: Nur SamsuDepartment of Internal Medicine, Division of Nephrology and Hypertension, Faculty of Medicine, Universitas Brawijaya, Malang, East Java, 65122, IndonesiaTel +62 812 331 6315Email samsu_nrs@yahoo.comBackground: Podocyte injury and its subsequent detachment play a critical role in the development and progression of diabetic nephropathy (DN). The objective of this study was to investigate the effect of rosmarinic acid (RA) in preventing podocyte detachment and inhibiting the progression of DN in streptozotocin (STZ)-induced diabetic in rats.Methods: We used 20 adult male Wistar rats as experimental animals, which were randomly divided into 5 groups (n=4 per group): nondiabetic rat group (negative control) and 4 groups of STZ-induced diabetic rats, namely, 1 group untreated diabetic rats (positive control) and 3 groups treated diabetic rats with RA 75 mg/kg, telmisartan (TMS) 1 mg/kg and combination of RA 75 mg/kg with TMS 1 mg/kg), respectively. After 8 weeks of therapy, urinary levels of podocin, nephrin and albumin and also serum cystatin C levels were examined by ELISA. The expression of p65 nuclear factor-kB by immunohistochemistry whereas expression of podocin and nephrin glomerulus were examined by immunofluorescence.Results: In the treated diabetic groups, we found that urinary level of podocin and nephrin, albumin urine excretion and serum cystatin C levels were significantly lower than the positive control group. Compared to negative controls, the group of treated diabetic rats did not differ significantly in preventing increased excretion of urinary nephrin and podocin. Meanwhile, treatment with RA monotherapy was significantly better than TMS or a combination of RA with TMS in reducing albumin excretion and preventing decreased kidney function.Conclusion: In STZ-induced diabetic rats, RA can prevent podocyte detachment. Treatment with RA and TMS either monotherapy or in combination can inhibit the development and progression of DN. However, the combination of both did not show a synergistic effect, even have higher urinary albumin excretion and worse kidney function compared to the RA monotherapy.Keywords: rosmarinic acid, telmisartan, podocin, nephrin, diabetic nephropathy

Abstract Background Wenshen Jianpi recipe (WSJPR), a blended traditional Chinese medicine, is considered to have the possible beneficial effect on the progression of diabetic nephropathy (DN). This present study was designed to elucidate this protective activity in a rat model with streptozotocin (STZ)-induced DN and to explore the possible underlying mechanism. Methods Adult Sprague Dawley (SD) rats were induced to develop DN through intraperitoneal injection of STZ (60 mg/kg). Animals were orally administered saline, WSJPR at 7.5, 15, 30 g/kg, and valsartan (25 mg/kg) daily for 8 weeks. Blood and 24-h urine samples of each rat were collected for biochemical examination at 2-week intervals. Microcirculatory blood flow in the renal cortex and hemorheology index were also measured. At the end of 8 weeks, all rats were sacrificed to obtain the kidney tissues for histological examination and reverse transcription polymerase chain reaction (RT-PCR) was used to analyze the transcriptional levels of nephrin and podocin genes. Results WSJPR could improve serum total protein (TP) and albumin (ALB), reduce the excretion rates of urine-TP (U-TP), urine-ALB (U-ALB) and urine urea nitrogen (UUN) (P

Abstract Background To establish a model of chronic renal fibrosis following acute kidney injury (AKI) in BALB/c mice and to observe the effect of AKI on podocyte injury and chronic fibrosis of the kidney. Additional aims included using the model to explore the role of podocyte injury in AKI and post-injury fibrosis. Methods Fifty BALB/C mice were randomly divided into control group (Ctr), sham group (sham), AKI 20 group (renal ischemia, 20 min reperfusion), AKI 30 group (renal ischemia, 30 min reperfusion) and AKI 40 group (renal ischemia, 40 min reperfusion). Mice serum and 24-h urine were collected on the 8th, 9th, 10th, 14th, and 28th days for urinary protein, serum creatinine (Scr) and blood urea nitrogen (BUN) analysis. HE staining, transmission electron microscopy (TEM), Masson staining, Q-PCR, Western Blot and immunohistochemistry were applied. Results Serum Scr and BUN levels across all AKI groups at the 9th day were significantly higher (P

Urolithins are bioactive compounds generated in human and animal intestines because of the bacterial metabolism of dietary ellagitannins (and their constituent, ellagic acid). Due to their multidirectional effects, including anti-inflammatory, antioxidant, anti-cancer, neuroprotective, and antiglycative properties, urolithins are potential novel therapeutic agents. In this study, while considering the future possibility of using urolithins to improve podocyte function in diabetes, we assessed the results of exposing mouse podocytes cultured in normal (NG, 5.5 mM) and high (HG, 25 mM) glucose concentrations to urolithin A (UA) and urolithin B (UB). Podocytes metabolized UA to form glucuronides in a time-dependent manner; however, in HG conditions, the metabolism was lower than in NG conditions. In HG milieu, UA improved podocyte viability more efficiently than UB and reduced the reactive oxygen species level. Both types of urolithins showed cytotoxic activity at high (100 µM) concentration. The UA upregulated total and surface nephrin expression, which was paralleled by enhanced nephrin internalization. Regulation of nephrin turnover was independent of ambient glucose concentration. We conclude that UA affects podocytes in different metabolic and functional aspects. With respect to its pro-survival effects in HG-induced toxicity, UA could be considered as a potent therapeutic candidate against diabetic podocytopathy.

Introduction Familial focal and segmental glomerulosclerosis (FFSGS) was found in a large cohort of patients in our previous study. Under the sponsorship of the National Natural Science Foundation of China, we conducted linkage analysis and full exon sequencing on the genomes of 54 patients diagnosed with FFSGS. The results revealed a FAM40A gene signature in those patients. To determine whether FAM40A was associated with podocyte lesions and whether changes in the podocyte cytoskeleton could affect podocyte function, mouse podocytes (MPs) were used in this study. Material and methods FAM40A silencing, over-expression and mutant-type over-expression models of renal MPs were established, whereby roles of wild-type FAM40A and mutant FAM40A (c.1562T>C, p521M>T) in regulating the function of the MP cytoskeleton were explored by using cellular immunofluorescence, RT-qPCR and Western blot. Results FAM40A was expressed and localized in MPs and significantly enriched in the nucleus and perinuclear zone. Changes of FAM40A expression altered the morphology of the MPs and their cytoskeletal organization, which was characterized by disordered distribution of F-actin, loss of the foot process architecture and the functional protein of the slit diaphragm nephrin (p < 0.05 or p T) led to the formation of round and blunt morphology of the MPs and loss of the foot-process structure. In addition, expression of the cytoskeletal protein F-actin was increased and concentrated in FAM40A mutated cells, whereas the expression of nephrin decreased in those cells (p T) was able to alter the morphology and cytoskeleton of the MPs, and to decrease the expression of nephrin, which may be the main factor contributing to FSGS.