scholarly journals Early podocyte injury and elevated levels of urinary podocyte-derived extracellular vesicles in swine with metabolic syndrome: role of podocyte mitochondria

2019 ◽  
Vol 317 (1) ◽  
pp. F12-F22 ◽  
Author(s):  
Li-Hong Zhang ◽  
Xiang-Yang Zhu ◽  
Alfonso Eirin ◽  
Arash Aghajani Nargesi ◽  
John R. Woollard ◽  
...  
Keyword(s):  
Metabolic Syndrome ◽  
Extracellular Vesicles ◽  
Light And Electron Microscopy ◽  
Urinary Concentration ◽  
Glomerular Injury ◽  
Podocyte Injury ◽  
Early Markers ◽  
Nutrient Surplus ◽  
Glomerular Size ◽  
Foot Process

Metabolic syndrome (MetS) is associated with nutrient surplus and kidney hyperfiltration, accelerating chronic renal failure. The potential involvement of podocyte damage in early MetS remains unclear. Mitochondrial dysfunction is an important determinant of renal damage, but whether it contributes to MetS-related podocyte injury remains unknown. Domestic pigs were studied after 16 wk of diet-induced MetS, MetS treated with the mitochondria-targeted peptide elamipretide (ELAM; 0.1 mg·kg−1·day−1 sc) for the last month of diet, and lean controls ( n = 6 pigs/group). Glomerular filtration rate (GFR) and renal blood flow (RBF) were measured using multidetector computed tomography, and podocyte and mitochondrial injury were measured by light and electron microscopy. Urinary levels of podocyte-derived extracellular vesicles (pEVs; nephrin positive/podocalyxin positive) were characterized by flow cytometry. Body weight, blood pressure, RBF, and GFR were elevated in MetS. Glomerular size and glomerular injury score were also elevated in MetS and decreased after ELAM treatment. Evidence of podocyte injury, impaired podocyte mitochondria, and foot process width were all increased in MetS but restored with ELAM. The urinary concentration of pEVs was elevated in MetS pigs and directly correlated with renal dysfunction, glomerular injury, and fibrosis and inversely correlated with glomerular nephrin expression. Additionally, pEV numbers were elevated in the urine of obese compared with lean human patients. Early MetS induces podocyte injury and mitochondrial damage, which can be blunted by mitoprotection. Urinary pEVs reflecting podocyte injury might represent early markers of MetS-related kidney disease and a novel therapeutic target.

scholarly journals AMP-Kinase mediates regulation of glomerular volume and podocyte survival

2021 ◽  
Author(s):  
Khadija Banu ◽  
Qisheng Lin ◽  
John M Basgen ◽  
Marina Planoutene ◽  
Chengguo Wei ◽  
...  
Keyword(s):  
Protective Role ◽  
Negative Regulator ◽  
Amp Kinase ◽  
Glomerular Injury ◽  
Podocyte Injury ◽  
Kinase Activation ◽  
Glomerular Volume ◽  
Foot Process ◽  
Injury Models

We reported that Shroom3 knockdown, via Fyn inhibition, induced albuminuria with foot process effacement (FPE) without glomerulosclerosis (FSGS) or podocytopenia. Interestingly, knockdown mice had reduced podocyte volumes. Human minimal change disease, where podocyte Fyn inactivation was reported, also showed lower glomerular volumes than FSGS. We hypothesized that lower glomerular volume prevented the progression to podocytopenia. To test this hypothesis, we utilized unilateral- and 5/6th nephrectomy models in Shroom3 knockdown mice. Knockdown mice exhibited lower glomerular volume, and less glomerular and podocyte hypertrophy after nephrectomy. FYN-knockdown podocytes had similar reductions in podocyte volume, implying Fyn was downstream of Shroom3. Using SHROOM3- or FYN-knockdown, we confirmed reduced podocyte protein content, along with significantly increased phosphorylated AMP-kinase, a negative regulator of anabolism. AMP-Kinase activation resulted from increased cytoplasmic redistribution of LKB1 in podocytes. Inhibition of AMP-Kinase abolished the reduction in glomerular volume and induced podocytopenia in mice with FPE, suggesting a protective role for AMP-Kinase activation. In agreement with this, treatment of glomerular injury models with AMP-Kinase activators restricted glomerular volume, podocytopenia and progression to FSGS. In summary, we demonstrate the important role of AMP-Kinase in glomerular volume regulation and podocyte survival. Our data suggest that AMP-Kinase activation adaptively regulates glomerular volume to prevent podocytopenia in the context of podocyte injury.

scholarly journals Podocyte Foot Process Effacement Precedes Albuminuria and Glomerular Hypertrophy in CD2-Associated Protein Deficient Mice

2021 ◽  
Vol 8 ◽  
Author(s):  
John M. Basgen ◽  
Jenny S. Wong ◽  
Justina Ray ◽  
Susanne B. Nicholas ◽  
Kirk N. Campbell
Keyword(s):  
Light And Electron Microscopy ◽  
Glomerular Hypertrophy ◽  
Mesangial Expansion ◽  
Podocyte Injury ◽  
Glomerular Volume ◽  
Urine Albumin ◽  
Foot Process Effacement ◽  
Foot Process ◽  
Grid Points ◽  
Deficient Mice

Background: Podocyte foot process effacement is a key histologic finding in proteinuric kidney disease. We previously showed that 3-week old CD2AP-deficient mice have significant proteinuria, glomerular hypertrophy and mesangial expansion. The goal of this study is to use morphometry to establish the temporal sequence of podocyte foot process effacement, glomerular volume expansion and albuminuria in Cd2ap−/− mice by measuring these parameters at the 2-week time point.Methods: Wild-type mice age 14 ± 1 days with the Cd2ap gene (WT, N = 5) and mice deficient for Cd2ap (Cd2ap KO, N = 5) were generated. Kidneys were harvested and fixed in 2.5% glutaraldehyde and processed for examination by light and electron microscopy. An average of 415.2 (range 268–716) grid points were counted for all the glomeruli, and quantification of glomerular volume from each kidney. Urine was collected the day prior to sacrifice for urine albumin-to-creatinine ratio (ACR) measurements.Results: There was no difference in albuminuria [median (range) mg/g] between WT [212.2 (177.6–388.4) mg/g] vs. Cd2ap KO mice [203.3 (164.7–910.2) mg/g], P = 0.89; or glomerular volume 68,307[10,931] vs. 66,844[13,022] μm3, p = 0.92. The volume densities of glomerular components of the podocyte, capillary lumen and mesangium were not different for the two groups, P = 0.14, 0.14 and 0.17 respectively. However, foot process width was increased in Cd2ap KO 1128[286] vs. WT [374 ± 42] nm, P = 0.02.Conclusion: Here we show that while 2-week old WT and Cd2ap KO mice have similar levels of albuminuria, glomerular and mesangial volume, Cd2ap KO mice have more extensive podocyte foot process effacement. The data suggests that podocyte injury is the initiating event leading to mesangial expansion and albuminuria in this model.

scholarly journals Extracellular Vesicles in Comorbidities Associated with Ischaemic Heart Disease: Focus on Sex, an Overlooked Factor

2021 ◽  
Vol 10 (2) ◽  
pp. 327
Author(s):  
Claudia Penna ◽  
Saveria Femminò ◽  
Giuseppe Alloatti ◽  
Maria F. Brizzi ◽  
Tommaso Angelone ◽  
...  
Keyword(s):  
Sex Differences ◽  
Extracellular Vesicles ◽  
Personalised Medicine ◽  
Myocardial Damage ◽  
Ischaemia Reperfusion Injury ◽  
Early Markers ◽  
Ischemic Diseases ◽  
Reduce Risk ◽  
Therapeutic Tools ◽  
Disease Focus

Extracellular vesicles (EV) are emerging early markers of myocardial damage and key mediators of cardioprotection. Therefore, EV are becoming fascinating tools to prevent cardiovascular disease and feasible weapons to limit ischaemia/reperfusion injury. It is well known that metabolic syndrome negatively affects vascular and endothelial function, thus creating predisposition to ischemic diseases. Additionally, sex is known to significantly impact myocardial injury and cardioprotection. Therefore, actions able to reduce risk factors related to comorbidities in ischaemic diseases are required to prevent maladaptive ventricular remodelling, preserve cardiac function, and prevent the onset of heart failure. This implies that early diagnosis and personalised medicine, also related to sex differences, are mandatory for primary or secondary prevention. Here, we report the contribution of EV as biomarkers and/or therapeutic tools in comorbidities predisposing to cardiac ischaemic disease. Whenever possible, attention is dedicated to data linking EV to sex differences.

Overexpression of angiotensin type 2 receptor ameliorates glomerular injury in a mouse remnant kidney model

2004 ◽  
Vol 286 (3) ◽  
pp. F516-F525 ◽  
Author(s):  
Naoko Hashimoto ◽  
Yohei Maeshima ◽  
Minoru Satoh ◽  
Masahiro Odawara ◽  
Hitoshi Sugiyama ◽  
...  
Keyword(s):  
Growth Factor ◽  
Transforming Growth Factor ◽  
Smooth Muscle Actin ◽  
Transforming Growth Factor Β ◽  
Glomerular Injury ◽  
Wild Mice ◽  
Angiotensin Type 2 Receptor ◽  
Glomerular Size ◽  
Nitric Oxide Metabolites

Angiotensin II mediates the progression of renal disease through the type 1 receptor (AT1R). Recent studies have suggested that type 2 receptor (AT2R)-mediated signaling inhibits cell proliferation by counteracting the actions of AT1R. The aim of the present study was to determine the effect of AT2R overexpression on glomerular injury induced by ⅚ nephrectomy (⅚Nx). AT2R transgenic mice (AT2-Tg), overexpressing AT2R under the control of α-smooth muscle actin (α-SMA) promoter, and control wild-type mice (Wild) were subjected to ⅚Nx. In AT2-Tg mice, the glomerular expression of AT2R was upregulated after ⅚Nx. Urinary albumin excretion at 12 wk after ⅚Nx was decreased by 33.7% in AT2-Tg compared with Wild mice. Glomerular size in AT2-Tg mice was significantly smaller than in Wild mice after ⅚Nx (93.1 ± 3.0 vs. 103.3 ± 1.8 μm; P < 0.05). Immunohistochemistry revealed significant decreases in glomerular expression of platelet-derived growth factor-BB chain (PDGF-BB) and transforming growth factor-β1 (TGF-β1) in AT2-Tg with ⅚Nx compared with Wild mice. Urinary excretion of nitric oxide metabolites was increased 2.5-fold in AT2-Tg compared with Wild mice. EMSA showed that activation of early growth response gene-1, which induces the transcription of PDGF-BB and TGF-β1, was decreased in AT2-Tg mice. These changes in AT2-Tg mice at 12 wk after ⅚Nx were blocked by the AT2R antagonist PD-123319. Taken together, our findings suggest that AT2R-mediated signaling may protect from glomerular injuries induced by ⅚Nx and that overexpression of AT2R may serve as a potential therapeutic strategy for glomerular disorders.

scholarly journals Astragalus membranaceus and Panax notoginseng, the Novel Renoprotective Compound, Synergistically Protect against Podocyte Injury in Streptozotocin-Induced Diabetic Rats

2019 ◽  
Vol 2019 ◽  
pp. 1-14 ◽  
Author(s):  
Ruonan Zhai ◽  
Guihua Jian ◽  
Teng Chen ◽  
Ling Xie ◽  
Rui Xue ◽  
...  
Keyword(s):  
Panax Notoginseng ◽  
Diabetic Rats ◽  
Astragalus Membranaceus ◽  
Protective Effects ◽  
The Novel ◽  
Podocyte Injury ◽  
Renal Histopathology ◽  
Foot Process ◽  
Immunofluorescence Labeling ◽  
Renal Expression

This study was aimed at investigating the synergistical protective effects of Astragalus membranaceus (AG) and Panax notoginseng (NG) on podocyte injury in diabetic rats. Diabetes was induced in rats by a single intraperitoneal injection of streptozotocin at 55 mg/kg. Diabetic rats were then orally administrated with losartan, AG, NG, and AG plus NG (2 : 1) for 12 weeks. Albuminuria, biochemical markers, renal histopathology, and podocyte number per glomerulus were measured. Podocyte apoptosis was determined by triple immunofluorescence labeling including TUNEL assay, WT1, and DAPI. Renal expression of nephrin, α-dystroglycan, Bax, Bcl-xl, and Nox4 was evaluated by immunohistochemistry, western blot, and RT-PCR. AG plus NG ameliorated albuminuria, renal histopathology, and podocyte foot process effacement to a greater degree than did AG or NG alone. The number of podocytes per glomerulus, as well as renal expression of nephrin, α-dystroglycan, and Bcl-xl, was decreased, while podocyte apoptosis, as well as renal expression of Bax and Nox4, was increased in diabetic rats. All of these abnormalities were partially restored by AG plus NG to a greater degree than did AG or NG alone. In conclusion, AG and NG synergistically ameliorated diabetic podocyte injury partly through upregulation of nephrin, α-dystroglycan, and Bcl-xl, as well as downregulation of Bax and Nox4. These findings might provide a novel treatment combination for DN.

scholarly journals P0338CRUMBS HOMOLOG2-EZRIN SIGNALING INDUCED PODOCYTE INJURY, LEADING TO MINIMAL-CHANGE DISEASE(MCD) AND FOCAL SEGMENTAL GLOMERULOSCLEROSIS(FSGS)

2020 ◽  
Vol 35 (Supplement_3) ◽  
Author(s):  
Ichiro Hada
Keyword(s):  
Electron Microscopy ◽  
Nephrotic Syndrome ◽  
Cell Line ◽  
Focal Segmental Glomerulosclerosis ◽  
Minimal Change Disease ◽  
Immunofluorescence Microscopy ◽  
Minimal Change ◽  
Podocyte Injury ◽  
Heavy Proteinuria ◽  
Foot Process

Abstract Background and Aims The etiology and cellular pathogenesis of podocyte injury leading to minimal-change disease (MCD) and focal segmental glomerulosclerosis (FSGS) remain largely obscure. Genetic mutation of crumbs homolog 2 (CRB2) is a cause of congenital nephrotic syndrome. Type-1 transmembrane proteins including CRB2 transduce outside-in signals that are involved in various cellular events including changes in the cytoskeletal network. The aim of the present study is to determine whether alteration of CRB2-mediated signaling in podocytes causes MCD and FSGS. Method Mice were immunized with a partial recombinant protein including the extracellular part of mouse CRB2. Urinalysis was obtained, and the kidney was subjected to histopathology. Kidney samples were also subjected to immunofluorescence microscopy and glomerular isolation to determine whether activation of the ezrin/radixin/moesin (ERM) family of cross-linkers between plasma membrane proteins and the actin cytoskeleton is involved in the pathogenesis of this nephrotic model. A CRB2-expressing mouse podocyte cell line was generated and incubated with anti-CRB2 antibody, and cell lysates were subjected to immunoblot analysis of ERM phosphorylation. The presence of anti-CRB2 antibody in the serum was determined by Western blot analysis. Results Apparent anti-CRB2 antibody was detected in the serum from 4 weeks onward. Immunized mice developed proteinuria at 4 weeks, which continued at least until 29 weeks. Mice developing extremely heavy proteinuria also developed hematuria from 18 weeks onward. Light microscopy revealed MCD in mice with proteinuria alone and FSGS in mice with heavy proteinuria and hematuria. Immunofluorescence microscopy revealed positive granular IgG staining in podocyte foot processes, but not complement C3. Electron microscopy and immuno-electron microscopy revealed alteration of actin organization associated with prominent foot process effacement. Strong phosphorylation of ezrin was observed in the glomerulus from the proteinuric stage and in the cellular lysates from the CRB2-expressing podocyte cell line incubated with anti-CRB2 antibody. Conclusion The current data revealed that binding of anti-CRB2 antibody to the extracellular domain of CRB2 on the podocyte foot process activated the ezrin-cytoskeleton network, leading to podocyte injury. Our data also indicated that signaling by this one molecular can induce two different phenotypes of glomerular injury: MCD and FSGS. In our model, the signaling was activated by anti-CRB2 antibody, but in patients with nephrotic syndrome the CRB2 ligands remain unknown. Therefore, it will be important to identify the soluble factors interacting with CRB2, which may be novel factors contributing to the pathogenesis of MCD and FSGS.

scholarly journals Extracellular Vesicles Promote Arteriogenesis in Chronically Ischemic Myocardium in the Setting of Metabolic Syndrome

2019 ◽  
Vol 8 (15) ◽  
Author(s):  
Laura A. Scrimgeour ◽  
Brittany A. Potz ◽  
Ahmad Aboul Gheit ◽  
Guangbin Shi ◽  
Melissa Stanley ◽  
...  
Keyword(s):  
Metabolic Syndrome ◽  
Extracellular Vesicles ◽  
Ischemic Myocardium

scholarly journals Podocyte Injury in Lupus Nephritis

2019 ◽  
Vol 8 (9) ◽  
pp. 1340 ◽  
Author(s):  
Hamza Sakhi ◽  
Anissa Moktefi ◽  
Khedidja Bouachi ◽  
Vincent Audard ◽  
Carole Hénique ◽  
...  
Keyword(s):  
Epithelial Cells ◽  
Lupus Nephritis ◽  
Lupus Erythematosus ◽  
Glomerular Injury ◽  
Crescent Formation ◽  
Podocyte Injury ◽  
Inflammatory Processes ◽  
Lupus Podocytopathy ◽  
Parietal Epithelial Cells ◽  
Lupus Glomerulonephritis

Systemic lupus erythematosus (SLE) is characterized by a broad spectrum of renal lesions. In lupus glomerulonephritis, histological classifications are based on immune-complex (IC) deposits and hypercellularity lesions (mesangial and/or endocapillary) in the glomeruli. However, there is compelling evidence to suggest that glomerular epithelial cells, and podocytes in particular, are also involved in glomerular injury in patients with SLE. Podocytes now appear to be not only subject to collateral damage due to glomerular capillary lesions secondary to IC and inflammatory processes, but they are also a potential direct target in lupus nephritis. Improvements in our understanding of podocyte injury could improve the classification of lupus glomerulonephritis. Indeed, podocyte injury may be prominent in two major presentations: lupus podocytopathy and glomerular crescent formation, in which glomerular parietal epithelial cells play also a key role. We review here the contribution of podocyte impairment to different presentations of lupus nephritis, focusing on the podocyte signaling pathways involved in these lesions.

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