-
Iranian Journal of Kidney Diseases May 2024Diabetic nephropathy (DN) belongs to the major cause of end-stage kidney disease. We probed the functions of a microRNA miR-33a in inducing podocytes injury during...
INTRODUCTION
Diabetic nephropathy (DN) belongs to the major cause of end-stage kidney disease. We probed the functions of a microRNA miR-33a in inducing podocytes injury during childhood DN (CDN).
METHODS
Kidney samples were collected from 20 children with DN. Matrix deposition and glomerular basement membranes thickness were examined by periodic acid-Schiff staining. Immunofluorescence staining was performed to assess kidney function-related proteins. MicroRNA (MiR)-33a mimic together with miR-33a inhibitor was transfected into podocytes for determining the roles of miR-33a. Glomerular podocyte apoptosis was determined by terminal deoxynucleotidyl transferase (TdT) dUTP Nick-End Labeling (TUNEL) staining along with flow cytometry.
RESULTS
Down-regulation of Nephrin and Podocin and increased podocyte apoptosis rate were observed in the glomerulus of CDN as well as podocytes treated with high glucose. MiR-33a was up regulated in the glomeruli and glucose-treated podocytes. Injury in podocytes was aggravated with miR-33a elevation but alleviated with miR-33a inhibition. Moreover, the expression of Sirtuin 6 (Sirt6) was decreased while the levels of notch receptor 1 (Notch1) and notch receptor 4 (Notch4) were elevated in the glomerulus and glucose-treated podocytes. Decreased level of Sirt6 upon glucose treatment was abrogated by miR-33a inhibition, and the podocytes injury induced by glucose exposure was relieved by Sirt6 via Notch signaling.
CONCLUSION
These findings indicated that miR-33a promoted podocyte injury via targeting Sirt6-dependent Notch signaling in CDN, which might provide a novel sight for CDN treatment. DOI: 10.52547/ijkd.7904.
Topics: MicroRNAs; Diabetic Nephropathies; Podocytes; Humans; Signal Transduction; Sirtuins; Apoptosis; Male; Child; Membrane Proteins; Female; Receptors, Notch; Intracellular Signaling Peptides and Proteins; Glucose; Up-Regulation; Receptor, Notch1; Down-Regulation
PubMed: 38904337
DOI: 10.52547/g7kbp983 -
Kidney International Jun 2024Vascularization plays a critical role in organ maturation and cell type development. Drug discovery, organ mimicry, and ultimately transplantation hinge on achieving...
Vascularization plays a critical role in organ maturation and cell type development. Drug discovery, organ mimicry, and ultimately transplantation hinge on achieving robust vascularization of in vitro engineered organs. Here, focusing on human kidney organoids, we overcame this hurdle by combining a human induced pluripotent stem cell (iPSC) line containing an inducible ETS translocation variant 2 (ETV2) (a transcription factor playing a role in endothelial cell development) that directs endothelial differentiation in vitro, with a non-transgenic iPSC line in suspension organoid culture. The resulting human kidney organoids show extensive endothelialization with a cellular identity most closely related to human kidney endothelia. Endothelialized kidney organoids also show increased maturation of nephron structures, an associated fenestrated endothelium with de novo formation of glomerular and venous subtypes, and the emergence of drug-responsive renin expressing cells. The creation of an engineered vascular niche capable of improving kidney organoid maturation and cell type complexity is a significant step forward in the path to clinical translation. Thus, incorporation of an engineered endothelial niche into a previously published kidney organoid protocol allowed the orthogonal differentiation of endothelial and parenchymal cell types, demonstrating the potential for applicability to other basic and translational organoid studies.
PubMed: 38901605
DOI: 10.1016/j.kint.2024.05.026 -
Biomedicine & Pharmacotherapy =... Jun 2024Astragaloside IV (AS-IV) exhibits diverse biological activities. Despite this, the detailed molecular mechanisms by which AS-IV ameliorates diabetic nephropathy (DN) and...
Phenylsulfate-induced oxidative stress and mitochondrial dysfunction in podocytes are ameliorated by Astragaloside IV activation of the SIRT1/PGC1α /Nrf1 signaling pathway.
Astragaloside IV (AS-IV) exhibits diverse biological activities. Despite this, the detailed molecular mechanisms by which AS-IV ameliorates diabetic nephropathy (DN) and shields podocytes from oxidative stress (OS) and mitochondrial dysfunction remain poorly understood. In this study, we used biochemical assays, histopathological analysis, Doppler ultrasound, transmission electron microscopy,flow cytometry, fluorescence staining, and Western blotting and other methods. AS-IV was administered to db/db mice for in vivo experimentation. Our findings indicated that AS-IV treatment significantly reduced diabetes-associated markers, proteinuria, and kidney damage. It also diminished ROS levels in the kidney, enhanced the expression of endogenous antioxidant enzymes, and improved mitochondrial health. Phenyl sulfate (PS), a protein-bound uremic solute of enteric origin, has been closely linked with DN and represents a promising avenue for further research. In vitro, PS exposure induced OS and mitochondrial dysfunction in podocytes, increasing ROS levels while decreasing antioxidant enzyme activity (Catalase, Heme Oxygenase-1, Superoxide Dismutase, and Glutathione Peroxidase). ROS inhibitors (N-acetyl-L-cysteine, NAC) as the positive control group can significantly reduce the levels of ROS and restore antioxidant enzymes protein levels. Additionally, PS reduced markers associated with mitochondrial biosynthesis and function (SIRT1, PGC1α, Nrf1, and TFAM). These adverse effects were partially reversed by AS-IV treatment. However, co-treatment with AS-IV and the SIRT1 inhibitor EX527 failed to restore these indicators. Overall, our study demonstrates that AS-IV effectively attenuates DN and mitigates PS-induced OS and mitochondrial dysfunction in podocytes via the SIRT1/PGC1α/Nrf1 pathway.
PubMed: 38901196
DOI: 10.1016/j.biopha.2024.117008 -
Journal of Medical Virology Jun 2024Pathogenic Eurasian hantaviruses cause hemorrhagic fever with renal syndrome (HFRS), which is characterized by acute kidney injury. The clinical course shows a broad...
Pathogenic Eurasian hantaviruses cause hemorrhagic fever with renal syndrome (HFRS), which is characterized by acute kidney injury. The clinical course shows a broad range of severity and is influenced by direct and immune-mediated effects. The neutrophil-to-lymphocyte ratio (NLR) is a marker of systemic inflammation and predicts severity and outcome in various diseases. Therefore, we examined the role of NLR in HFRS caused by hantavirus Puumala (PUUV) and its association with disease severity and kidney injury. We detected elevated NLR levels on admission (NLR: median 3.82, range 1.75-7.59), which increased during acute HFRS. Maximum NLR levels (NLR: median 4.19, range 1.75-13.16) were 2.38-fold higher compared to the reference NLR level of 1.76 in the general population. NLR levels on admission correlate with markers of severity (length of hospital stay, serum creatinine) but not with other markers of severity (leukocytes, platelets, C-reactive protein, lactate dehydrogenase, serum albumin, proteinuria). Interestingly, levels of nephrin, which is a specific marker of podocyte damage in kidney injury, are highest on admission and correlate with NLR, but not with NLR. Together, we observed a correlation between systemic inflammation and the severity of HFRS, but our results also revealed that podocyte damage precedes these inflammatory processes.
Topics: Humans; Neutrophils; Hemorrhagic Fever with Renal Syndrome; Male; Adult; Biomarkers; Lymphocytes; Middle Aged; Female; Severity of Illness Index; Puumala virus; Aged; Young Adult; Acute Kidney Injury
PubMed: 38899399
DOI: 10.1002/jmv.29759 -
The Journal of Biological Chemistry Jun 2024Phospholipase A2 receptor 1 (PLA2R1) is a 180-kDa transmembrane protein that plays a role in inflammation and cancer, and is the major autoantigen in membranous...
Phospholipase A2 receptor 1 (PLA2R1) is a 180-kDa transmembrane protein that plays a role in inflammation and cancer, and is the major autoantigen in membranous nephropathy (MN), a rare but severe autoimmune kidney disease. A soluble form of PLA2R1 has been detected in mouse and human serum. It is likely produced by proteolytic shedding of membrane-bound PLA2R1 but the mechanism is unknown. Here, we show that human PLA2R1 is cleaved by A Disintegrin And Metalloprotease 10 (ADAM10) and ADAM17 in HEK293 cells, mouse embryonic fibroblasts and human podocytes. By combining site-directed mutagenesis and sequencing, we determined the exact cleavage site within the extracellular juxtamembrane stalk of human PLA2R1. Orthologs and paralogs of PLA2R1 are also shed. By using pharmacological inhibitors and genetic approaches with RNA interference and knock-out cellular models, we identified a major role of ADAM10 in the constitutive shedding of PLA2R1, and a dual role of ADAM10 and ADAM17 in the stimulated shedding. We did not observe evidence for cleavage by β- or γ-secretase, suggesting that PLA2R1 may not be a substrate for Regulated Intramembrane Proteolysis. PLA2R1 shedding occurs constitutively and can be triggered by the calcium ionophore ionomycin, the protein kinase C inducer PMA, cytokines and lipopolysaccharides, in vitro and in vivo. Altogether, our results show that PLA2R1 is a novel substrate for ADAM10 and ADAM17, producing a soluble form that is increased in inflammatory conditions and likely exerts various functions in physiological and pathophysiological conditions including inflammation, cancer and MN.
PubMed: 38897568
DOI: 10.1016/j.jbc.2024.107480 -
Canadian Journal of Kidney Health and... 2024Diabetic kidney disease (DKD) is the most common and deranging microvascular complication of diabetes mellitus (DM). Podocytopathy is a key component of glomerular...
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; < .0001). There was a correlation between miRNA-21 and UACR (r = 0.604; < .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.
PubMed: 38894727
DOI: 10.1177/20543581241260948 -
International Journal of Molecular... May 2024Following the discovery of podocyte phospholipase A2 receptor and thrombospondin type-1 domain-containing 7A, various potential target antigens for membranous... (Review)
Review
Following the discovery of podocyte phospholipase A2 receptor and thrombospondin type-1 domain-containing 7A, various potential target antigens for membranous nephropathy (MN) have been reported one after another. MN target antigens have now been identified in a significant proportion of patients, and a new classification framework classifies patients with MN based on the detected antigen and associated disease phenotype. A serology-based approach that does not require a histological diagnosis for patients suspected of having MN has also been proposed. However, there have been cases in which dual positivity for MN antigens and/or corresponding antibodies has been shown. Importantly, some of them showed a transition of the affected patient's immune responses to MN antigens, suggesting that serological diagnosis changes depending on the timing of the analysis. In this review, we provide detailed information on these cases and present an overview of our recent understanding of their putative mechanisms involved in these cases. Greater awareness is required to adequately recognize and develop appropriate therapeutic strategies for this condition.
Topics: Glomerulonephritis, Membranous; Humans; Receptors, Phospholipase A2; Autoantigens; Prevalence; Podocytes; Autoantibodies; Thrombospondins
PubMed: 38892120
DOI: 10.3390/ijms25115931 -
International Journal of Molecular... May 2024Approximately 30% of steroid-resistant nephrotic syndromes are attributed to monogenic disorders that involve 27 genes. Mutations in family members have also been...
Approximately 30% of steroid-resistant nephrotic syndromes are attributed to monogenic disorders that involve 27 genes. Mutations in family members have also been linked to nephrotic syndrome; however, the precise mechanism remains elusive. To investigate this, podocyte-specific knockout mice were generated to examine phenotypic changes. In the initial assessment under normal conditions, knockout mice showed no significant differences in the urinary albumin-creatinine ratio, blood urea nitrogen, serum creatinine levels, or histological features compared to controls. However, following kidney injury with adriamycin, podocyte-specific knockout mice exhibited a significantly higher albumin-creatinine ratio and a significantly greater sclerotic index than control mice. Electron microscopy revealed more extensive foot process effacement in the knockout mice than in control mice. In addition, -deficient human podocytes showed increased detachment and apoptosis following adriamycin exposure. These findings suggest that KANK1 may play a protective role in mitigating podocyte damage under pathological conditions.
Topics: Podocytes; Animals; Mice; Humans; Mice, Knockout; Doxorubicin; Cytoskeletal Proteins; Adaptor Proteins, Signal Transducing; Apoptosis; Nephrotic Syndrome; Male; Tumor Suppressor Proteins
PubMed: 38891998
DOI: 10.3390/ijms25115808 -
International Journal of Molecular... May 2024The mechanism underlying podocyte dysfunction in minimal change disease (MCD) remains unknown. This study aimed to shed light on the potential pathophysiology of MCD...
The mechanism underlying podocyte dysfunction in minimal change disease (MCD) remains unknown. This study aimed to shed light on the potential pathophysiology of MCD using glomerular proteomic analysis. Shotgun proteomics using label-free quantitative mass spectrometry was performed on formalin-fixed, paraffin-embedded (FFPE) renal biopsies from two groups of samples: control (CTR) and MCD. Glomeruli were excised from FFPE renal biopsies using laser capture microdissection (LCM), and a single-pot solid-phase-enhanced sample preparation (SP3) digestion method was used to improve yield and protein identifications. Principal component analysis (PCA) revealed a distinct separation between the CTR and MCD groups. Forty-eight proteins with different abundance between the two groups (-value ≤ 0.05 and |FC| ≥ 1.5) were identified. These may represent differences in podocyte structure, as well as changes in endothelial or mesangial cells and extracellular matrix, and some were indeed found in several of these structures. However, most differentially expressed proteins were linked to the podocyte cytoskeleton and its dynamics. Some of these proteins are known to be involved in focal adhesion (NID1 and ITGA3) or slit diaphragm signaling (ANXA2, TJP1 and MYO1C), while others are structural components of the actin and microtubule cytoskeleton of podocytes (ACTR3 and NES). This study suggests the potential of mass spectrometry-based shotgun proteomic analysis with LCM glomeruli to yield valuable insights into the pathogenesis of podocytopathies like MCD. The most significantly dysregulated proteins in MCD could be attributable to cytoskeleton dysfunction or may be a compensatory response to cytoskeleton malfunction caused by various triggers.
Topics: Humans; Nephrosis, Lipoid; Proteomics; Podocytes; Kidney Glomerulus; Male; Female; Adult; Proteome; Laser Capture Microdissection; Middle Aged
PubMed: 38891801
DOI: 10.3390/ijms25115613 -
Cells May 2024Podocyte health is vital for maintaining proper glomerular filtration in the kidney. Interdigitating foot processes from podocytes form slit diaphragms which regulate... (Review)
Review
Podocyte health is vital for maintaining proper glomerular filtration in the kidney. Interdigitating foot processes from podocytes form slit diaphragms which regulate the filtration of molecules through size and charge selectivity. The abundance of lipid rafts, which are ordered membrane domains rich in cholesterol and sphingolipids, near the slit diaphragm highlights the importance of lipid metabolism in podocyte health. Emerging research shows the importance of sphingolipid metabolism to podocyte health through structural and signaling roles. Dysregulation in sphingolipid metabolism has been shown to cause podocyte injury and drive glomerular disease progression. In this review, we discuss the structure and metabolism of sphingolipids, as well as their role in proper podocyte function and how alterations in sphingolipid metabolism contributes to podocyte injury and drives glomerular disease progression.
Topics: Podocytes; Sphingolipids; Humans; Animals; Lipid Metabolism; Kidney Diseases; Membrane Microdomains
PubMed: 38891023
DOI: 10.3390/cells13110890