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Clinica Chimica Acta; International... Jun 2024Diabetic nephropathy (DN), a significant consequence of diabetes, is associated with adverse cardiovascular and renal disease as well as mortality. Although... (Review)
Review
Diabetic nephropathy (DN), a significant consequence of diabetes, is associated with adverse cardiovascular and renal disease as well as mortality. Although microalbuminuria is considered the best non-invasive marker for DN, better predictive markers are needed of sufficient sensitivity and specificity to detect disease in general and in early disease specifically. Even prior to appearance of microalbuminuria, urinary biomarkers increase in diabetics and can serve as accurate nephropathy biomarkers even in normoalbuminuria. In this review, a number of novel urine biomarkers including those reflecting kidney damage caused by glomerular/podocyte damage, tubular damage, oxidative stress, inflammation, and intrarenal renin-angiotensin system activation are discussed. Our review also includes emerging biomarkers such as urinary microRNAs. These short noncoding miRNAs regulate gene expression and could be utilized to identify potential novel biomarkers in DN development and progression. .
PubMed: 38844018
DOI: 10.1016/j.cca.2024.119762 -
The Journal of Clinical Investigation Jun 2024Proliferative glomerulonephritis is a severe condition often leading to kidney failure. There is a significant lack of effective treatment for these disorders. Here,...
Proliferative glomerulonephritis is a severe condition often leading to kidney failure. There is a significant lack of effective treatment for these disorders. Here, following the identification of a somatic PIK3CA gain-of-function mutation in podocytes of a patient, we demonstrate using multiple genetically engineered mouse models, single-cell RNA sequencing and spatial transcriptomics the crucial role played by this pathway for proliferative glomerulonephritis development by promoting podocyte proliferation, dedifferentiation and inflammation. Additionally, we show that alpelisib, a PI3Kα inhibitor, improves glomerular lesions and kidney function in different mouse models of proliferative glomerulonephritis and lupus nephritis by targeting podocytes. Surprisingly, we determined that pharmacological inhibition of PI3Kα affects B and T lymphocyte population in lupus nephritis mouse models with decrease in the production of proinflammatory cytokines, autoantibodies and glomerular complement deposition, which are all characteristic features of PI3K delta (PI3Kδ) inhibition, the primary PI3K isoform expressed in lymphocytes. Importantly, PI3Kα inhibition does not impact lymphocyte function under normal conditions. These findings were then confirmed in human lymphocytes isolated from patients with active lupus nephritis. In conclusion, we demonstrate the major role played by PI3Kα in proliferative glomerulonephritis and show that in this condition, alpelisib acts on both podocytes and the immune system.
PubMed: 38842935
DOI: 10.1172/JCI176402 -
Nephrology (Carlton, Vic.) Jun 2024Primary coenzyme Q10 deficiency-1, caused by COQ2 disease-causing variants, is an autosomal recessive disorder, and genetic testing is the gold standard for diagnosing...
Primary coenzyme Q10 deficiency-1, caused by COQ2 disease-causing variants, is an autosomal recessive disorder, and genetic testing is the gold standard for diagnosing this condition. A Chinese boy with steroid-resistant nephrotic syndrome, focal segmental glomerulosclerosis, and progressive kidney insufficiency was included in the study. Electron microscopy revealed the glomerular basement membrane with irregular thickness and lamellation with diffuse effacement of foot processes in the podocytes, and swollen mitochondria with abnormal cristae in the podocytes. Coenzyme Q10 supplementation started about 3 weeks after the onset of mild kidney dysfunction did not improve the proband's kidney outcome. Proband-only whole-exome sequencing and Sanger sequencing revealed two heteroallelic COQ2 variants: a maternally inherited novel variant c.1013G > A[p.(Gly338Glu)] in exon 6 and a variant of unknown origin c.1159C > T[p.(Arg387*)] in exon 7. Subsequent long-read sequencing demonstrated these two variants were located on different alleles. Our report extends the phenotypic and genotypic spectrum of COQ2 glomerulopathy.
PubMed: 38838054
DOI: 10.1111/nep.14329 -
Nephrology (Carlton, Vic.) Jun 2024Apoptosis and oxidative stress in kidneys are critical players in acute kidney injury (AKI). Rehmapicrogenin, a monomeric compound extracted from Rehmanniae radix, has...
Rehmapicrogenin attenuates lipopolysaccharide-induced podocyte injury and kidney dysfunctions by regulating nuclear factor E2-related factor 2/antioxidant response element signalling.
BACKGROUND
Apoptosis and oxidative stress in kidneys are critical players in acute kidney injury (AKI). Rehmapicrogenin, a monomeric compound extracted from Rehmanniae radix, has been found to possess nitric oxide inhibitory and anti-inflammatory activities. Thus, this study aimed to investigate the roles and mechanisms of rehmapicrogenin in AKI.
METHODS
Lipopolysaccharide (LPS) was used to induce AKI-like conditions. Cell survival conditions were detected by cell counting kit-8 assays and flow cytometry. Several renal function markers including blood urea nitrogen, proteinuria, creatinine, and albumin were measured. Apoptosis and reactive oxygen species (ROS) production were examined by TUNEL and dihydroethidium staining, respectively. Haematoxylin-eosin staining and periodic acid-Schiff staining were conducted to assess histopathological changes. Gene expression was evaluated by western blotting, commercially available kits and immunofluorescence staining.
RESULTS
For in vitro analysis, rehmapicrogenin inhibited the LPS-induced podocyte apoptosis by activating the Nrf2/ARE pathway. For in vivo analysis, rehmapicrogenin improved renal functions in LPS-induced mice. Additionally, rehmapicrogenin suppressed LPS-induced podocyte apoptosis and oxidative stress in kidney tissues. Mechanistically, rehmapicrogenin activated the Nrf2/ARE pathway in LPS-induced mice.
CONCLUSION
Rehmapicrogenin relieves the podocyte injury and renal dysfunctions through activating the Nrf2/ARE pathway to inhibit apoptosis and oxidative stress.
PubMed: 38837564
DOI: 10.1111/nep.14310 -
Histology and Histopathology May 2024Hyperglycemia is a risk factor for impaired renal function, including cellular metabolic disturbance, apoptosis, inflammation, and histologic lesion. This study aims to...
BACKGROUND
Hyperglycemia is a risk factor for impaired renal function, including cellular metabolic disturbance, apoptosis, inflammation, and histologic lesion. This study aims to investigate the potential therapeutic targeting of cyclin-dependent kinase 5 (Cdk5) in hyperglycemia-induced podocyte dysfunction and renal damage.
METHODS
Cell viability and apoptosis of podocytes were assessed through CCK-8 and TUNEL staining, respectively, following exposure to normal glucose (NG; 5 mM), high glucose (HG; 30 mM), or treatment with Cdk5 inhibitors (trans-resveratrol, myricetin, salvianolic acid A, and BML-259). Diabetic mice were established by intraperitoneal injection of freshly streptozotocin (STZ), which was given at a dose of 35 mg/kg in five successive injections. Additionally, histochemical staining was employed to evaluate the morphologic lesion of the kidney.
RESULTS
Cdk5 was found to be activated by HG stimulation both and . Notably, the inhibition of Cdk5 effectively mitigated the podocyte dysfunction induced by HG, including growth inhibition, membrane damage, and apoptosis. The compounds Trans-resveratrol, myricetin, salvianolic acid A, and BML-259 exhibited low binding energy values of -8.032 kcal/mol, -8.693 kcal/mol, -8.743 kcal/mol, and -10.952 kcal/mol, respectively, indicating strong and stable binding affinity between these candidates and Cdk5. The results of experimental analysis demonstrate that Cdk5 inhibitors, namely trans-resveratrol, myricetin, salvianolic acid A, and BML-259, confer protection against tubular and glomerular lesions induced by hyperglycemia.
CONCLUSION
Both myricetin and BML-259 exhibit comparable protective effects on renal injury by inhibiting Cdk5.
PubMed: 38835215
DOI: 10.14670/HH-18-764 -
BMC Medical Genomics Jun 2024To investigate the role of BTG2 in periodontitis and diabetic kidney disease (DKD) and its potential underlying mechanism.
OBJECTIVE
To investigate the role of BTG2 in periodontitis and diabetic kidney disease (DKD) and its potential underlying mechanism.
METHODS
Gene expression data for periodontitis and DKD were acquired from the Gene Expression Omnibus (GEO) database. Differential expression analysis identified co-expressed genes between these conditions. The Nephroseq V5 online nephropathy database validated the role of these genes in DKD. Pearson correlation analysis identified genes associated with our target gene. We employed Gene Set Enrichment Analysis (GSEA) and Protein-Protein Interaction (PPI) networks to elucidate potential mechanisms. Expression levels of BTG2 mRNA were examined using quantitative polymerase Chain Reaction (qPCR) and immunofluorescence assays. Western blotting quantified proteins involved in epithelial-to-mesenchymal transition (EMT), apoptosis, mTORC1 signaling, and autophagy. Additionally, wound healing and flow cytometric apoptosis assays evaluated podocyte migration and apoptosis, respectively.
RESULTS
Analysis of GEO database data revealed BTG2 as a commonly differentially expressed gene in both DKD and periodontitis. BTG2 expression was reduced in DKD compared to normal conditions and correlated with proteinuria. GSEA indicated enrichment of BTG2 in the EMT and mTORC1 signaling pathways. The PPI network highlighted BTG2's relevance to S100A9, S100A12, and FPR1. Immunofluorescence assays demonstrated significantly lower BTG2 expression in podocytes under high glucose (HG) conditions. Reduced BTG2 expression in HG-treated podocytes led to increased levels of EMT markers (α-SMA, vimentin) and the apoptotic protein Bim, alongside a decrease in nephrin. Lower BTG2 levels were associated with increased podocyte mobility and apoptosis, as well as elevated RPS6KB1 and mTOR levels, but reduced autophagy marker LC3.
CONCLUSION
Our findings suggest that BTG2 is a crucial intermediary gene linking DKD and periodontitis. Modulating autophagy via inhibition of the mTORC1 signaling pathway, and consequently suppressing EMT, may be pivotal in the interplay between periodontitis and DKD.
Topics: Periodontitis; Diabetic Nephropathies; Humans; Tumor Suppressor Proteins; Epithelial-Mesenchymal Transition; Apoptosis; Immediate-Early Proteins; Podocytes; Signal Transduction; Autophagy; Protein Interaction Maps; Mechanistic Target of Rapamycin Complex 1; Cell Movement
PubMed: 38831322
DOI: 10.1186/s12920-024-01915-6 -
Toxicology Research Jun 2024Diabetic nephropathy (DN) is the most common microvascular complication of diabetes mellitus (DM), being the second cause of end-stage renal disease globally. Podocyte...
BACKGROUND
Diabetic nephropathy (DN) is the most common microvascular complication of diabetes mellitus (DM), being the second cause of end-stage renal disease globally. Podocyte injury is closely associated with DN developmen. Our study aimed to investigate the role of long non-coding RNA (lncRNA) TTN-AS1 in DN-associated podocyte injury.
METHODS
The mouse podocyte cell line (MPC5) and human primary podocytes were stimulated by high glucose (HG; 30 nM glucose) to establish the cellular model of DN. Before HG stimulation, both podocytes were transfected with sh-TTN-AS1#1/2 or pcDNA3.1/STAT3 to evaluate the influence of TTN-AS1 knockdown or STAT3 overexpression on HG-induced podocyte injury. TTN-AS1 and STAT3 expression in both podocytes was examined by RT-qPCR. Cell viability and death were assessed by CCK-8 and LDH release assay. ELISA was adopted for testing IL-6 and TNF-α contents in cell supernatants. The levels of oxidative stress markers (ROS, MDA, SOD, and GSH) in cell supernatants were determined by commercial kits. Western blotting was used for measuring the expression of fibrosis markers (fibronectin and α-SMA and podocyte function markers (podocin and nephrin) in podocytes.
RESULTS
HG stimulation led to decreased cell viability, increased cell death, fibrosis, inflammation, cell dysfunction and oxidative stress in podocytes. However, knockdown of TTN-AS1 ameliorated HG-induced podocyte injury. Mechanically, the transcription factor STAT3 interacted with TTN-AS1 promoter and upregulated TTN-AS1 expression. STAT3 overexpression offset the protective effect of TTN-AS1 silencing on HG-induced podocyte damage.
CONCLUSION
Overall, STAT3-mediated upregulation of lncRNA TTN-AS1 could exacerbate podocyte injury in DN through suppressing inflammation and oxidative stress.
PubMed: 38828128
DOI: 10.1093/toxres/tfae079 -
Kidney International May 2024Unlike classical protein kinase A, with separate catalytic and regulatory subunits, EPACs are single chain multi-domain proteins containing both catalytic and regulatory...
Unlike classical protein kinase A, with separate catalytic and regulatory subunits, EPACs are single chain multi-domain proteins containing both catalytic and regulatory elements. The importance of cAMP-Epac-signaling as an energy provider has emerged over the last years. However, little is known about Epac1 signaling in chronic kidney disease. Here, we examined the role of Epac1 during the progression of glomerulonephritis (GN). We first observed that total genetic deletion of Epac1 in mice accelerated the progression of nephrotoxic serum (NTS)-induced GN. Next, mice with podocyte-specific conditional deletion of Epac1 were generated and showed that NTS-induced GN was exacerbated in these mice. Gene expression analysis in glomeruli at the early and late phases of GN showed that deletion of Epac1 in podocytes was associated with major alterations in mitochondrial and metabolic processes and significant dysregulation of the glycolysis pathway. In vitro, Epac1 activation in a human podocyte cell line increased mitochondrial function to cope with the extra energy demand under conditions of stress. Furthermore, Epac1-induced glycolysis and lactate production improved podocyte viability. To verify the in vivo therapeutic potential of Epac1 activation, the Epac1 selective cAMP mimetic 8-pCPT was administered in wild type mice after induction of GN. 8-pCPT alleviated the progression of GN by improving kidney function with decreased structural injury with decreased crescent formation and kidney inflammation. Importantly, 8-pCPT had no beneficial effect in mice with Epac1 deletion in podocytes. Thus, our data suggest that Epac1 activation is an essential protective mechanism in GN by reprogramming podocyte metabolism. Hence, targeting Epac1 activation could represent a potential therapeutic approach.
PubMed: 38821447
DOI: 10.1016/j.kint.2024.05.010 -
Journal of Cellular and Molecular... Jun 2024As an advance laboratory model, three-dimensional (3D) organoid culture has recently been recruited to study development, physiology and abnormality of kidney tissue....
As an advance laboratory model, three-dimensional (3D) organoid culture has recently been recruited to study development, physiology and abnormality of kidney tissue. Micro-tissues derived from primary renal cells are composed of 3D epithelial structures representing the main characteristics of original tissue. In this research, we presented a simple method to isolate mouse renal clonogenic mesenchymal (MLCs) and epithelial-like cells (ELCs). Then we have done a full characterization of MLCs using flow cytometry for surface markers which showed that more than 93% of cells expressed these markers (Cd44, Cd73 and Cd105). Epithelial and stem/progenitor cell markers characterization also performed for ELC cells and upregulating of these markers observed while mesenchymal markers expression levels were not significantly increased in ELCs. Each of these cells were cultured either alone (ME) or in combination with human umbilical vein endothelial cells (HUVECs) (MEH; with an approximate ratio of 10:5:2) to generate more mature kidney structures. Analysis of 3D MEH renal micro-tissues (MEHRMs) indicated a significant increase in renal-specific gene expression including Aqp1 (proximal tubule), Cdh1 (distal tubule), Umod (loop of Henle), Wt1, Podxl and Nphs1 (podocyte markers), compared to those groups without endothelial cells, suggesting greater maturity of the former tissue. Furthermore, ex ovo transplantation showed greater maturation in the constructed 3D kidney.
Topics: Animals; Kidney; Humans; Human Umbilical Vein Endothelial Cells; Mice; Organoids; Epithelial Cells; Cell Differentiation; Biomarkers; Mesenchymal Stem Cells; Cell Culture Techniques, Three Dimensional
PubMed: 38818569
DOI: 10.1111/jcmm.18453 -
Biochemical Pharmacology Jul 2024Early stages of diabetes are characterized by elevations of insulin and glucose concentrations. Both factors stimulate reactive oxygen species (ROS) production, leading...
Early stages of diabetes are characterized by elevations of insulin and glucose concentrations. Both factors stimulate reactive oxygen species (ROS) production, leading to impairments in podocyte function and disruption of the glomerular filtration barrier. Podocytes were recently shown to be an important source of αKlotho (αKL) expression. Low blood Klotho concentrations are also associated with an increase in albuminuria, especially in patients with diabetes. We investigated whether ADAM10, which is known to cleave αKL, is activated in glomeruli and podocytes under diabetic conditions and the potential mechanisms by which ADAM10 mediates ROS production and disturbances of the glomerular filtration barrier. In cultured human podocytes, high glucose increased ADAM10 expression, shedding, and activity, NADPH oxidase activity, ROS production, and albumin permeability. These effects of glucose were inhibited when cells were pretreated with an ADAM10 inhibitor or transfected with short-hairpin ADAM10 (shADAM10) or after the addition soluble Klotho. We also observed increases in ADAM10 activity, NOX4 expression, NADPH oxidase activity, and ROS production in αKL-depleted podocytes. This was accompanied by an increase in albumin permeability in shKL-expressing podocytes. The protein expression and activity of ADAM10 also increased in isolated glomeruli and urine samples from diabetic rats. Altogether, these results reveal a new mechanism by which hyperglycemia in diabetes increases albumin permeability through ADAM10 activation and an increase in oxidative stress via NOX4 enzyme activation. Moreover, αKlotho downregulates ADAM10 activity and supports redox balance, consequently protecting the slit diaphragm of podocyteσ under hyperglycemic conditions.
Topics: Podocytes; Klotho Proteins; ADAM10 Protein; Reactive Oxygen Species; Humans; Animals; Glucuronidase; Amyloid Precursor Protein Secretases; Membrane Proteins; Rats; Male; Diabetes Mellitus, Experimental; NADPH Oxidase 4; NADPH Oxidases; Cells, Cultured; Glucose; Rats, Sprague-Dawley
PubMed: 38815628
DOI: 10.1016/j.bcp.2024.116328