DigitalUM :: Browsing by Subject "Podocyte"

Browsing by Subject "Podocyte"

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Open Access
Cyclin-dependent kinase 5 as a potential therapeutic target to alleviate high glucose-induced podocyte apoptosis and hyperglycemia-induced renal injury in mice
(Universidad de Murcia, Departamento de Biologia Celular e Histiologia, 2025) Zhao, Li; Gu, Wenjuan; He, Wenfang; Yang, Kaibi; Yang, Nan; Jia, Yanqing
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 in vitro and in vivo. 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 in vivo 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
Open Access
Death-associated protein kinase 1 correlates with podocyte apoptosis and renal damage and can be mediated by miR-361
(Universidad de Murcia, Departamento de Biologia Celular e Histiologia, 2021) Wu, Guang-jun; Zhao, Hong-biao; Zhang, Xiao-wei
Background. Herein, we aimed to determine whether DAPK1 and its post-transcriptional regulator miR-361 were implicated in high glucose (HG)-induced podocyte injury and renal damage in db/db mice. Materials and methods. Podocytes were incubated with normal glucose (NG; 5 mM) or HG (30 mM). Podocyte apoptosis was evaluated using TUNEL staining. Lentiviral-delivered specific short hairpin RNA (shRNA) was designed to silence DAPK1 expression in podocytes. miR-361 agomir was administrated by tail intravenous injection in db/db diabetic mice to investigate the renoprotection of miR-361 in vivo. Results. Exposure of podocytes to HG led to a significant increase in DAPK1 mRNA and protein levels and a decrease in miR-361 expression levels. Knockdown of DAPK1 attenuated HG-triggered growth inhibition, apoptosis, DNA damage and cell membrane damage in podocytes. Mechanically, DAPK1 was a direct target of miR-361. Transfection with miR-361 mimics into podocytes resulted in a significant decrease in the DAPK1 protein expression level. In addition, HGinduced the up-regulation of the DAPK1 protein expression level in podocytes was restrained by miR-361 mimics transfection. Intriguingly, overexpression of DAPK1 in HG-stimulated podocytes muted miR-361- mediated cytoprotection, including anti-apoptosis, resistance to DNA and membrane damage. In vivo, overexpression of miR-361 protected against hyperglycemia-induced podocyte loss, tubular atrophy and interstitial fibrosis in the kidney of db/db mice. Moreover, overexpression of miR-361 inhibited the protein expression of DAPK1 in the kidney of db/db mice. Conclusion. Our research presented a novel mechanism of HG-induced podocyte damage or renal lesion, supporting the miR-361/DAPK1 signaling pathway that could be used as a potential therapeutic target for the treatment of DN.
Open Access
Differential role of mesangial cells and podocytes in TGF-ß-induced mesangial matrix synthesis in chronic glomerular disease
(Murcia : F. Hernández, 2009) Lee, Hyun Soon; Song, Chi Young
Glomerulosclerosis is characterized by mesangial matrix accumulation that is mediated primarily by activation of transforming growth factor-ß (TGF-ß). Unlike podocytes, mesangial cells secrete TGF-ß in response to common in vitro fibrogenic stimuli. However, mesangial immunostaining for active TGF-ß1 in chronic glomerular disease is almost negligible, despite increased mesangial TGF-ß1 mRNA expression, while podocytes covering the sclerotic glomerular segments exhibit increased TGF-ß1 protein expression. The mechanisms whereby TGF-ß is activated in the diseased glomeruli and how the activated TGF-ß leads to mesangial matrix overproduction are not clear. We provide evidence that TGF-ß secreted as latent complexes by mesangial cells is stored in the mesangial matrix, from which soluble forms of latent TGF-ß are released and localized to the podocyte surface in chronic glomerular disease. Podocyte-derived reactive oxygen species, plasmin and thrombospondin-1, particularly renin-angiotensin-aldosterone system-induced oxidative stress, seem to be involved in TGF-ß activation in podocytes. We also provide evidence that the TGF-ß- induced secretion of connective tissue growth factor and vascular endothelial growth factor by podocytes acts as a paracrine regulatory mechanism on mesangial cells, which may cause mesangial matrix accumulation culminating in the development of glomerulosclerosis. Collectively, these data bring new insights into our understanding of the roles of the mesangial cells and podocytes in the TGF-ß-induced mesangial matrix synthesis in chronic glomerular disease.
Open Access
HGSNAT enzyme deficiency results in accumulation of heparan sulfate in podocytes and basement membranes
(Universidad de Murcia, Departamento de Biologia Celular e Histiologia, 2019) Nagel, Lauren; Oliveira, Regiana; Pshezhetsky, Alexey V.; Morales, Carlos R.
ucopolysaccharidosis III type C is a lysosomal storage disorder caused by the accumulation of heparan sulfate in lysosomes. The disorder occurs due to Heparan Acetyl-CoA: α-glucosaminide N- acetyltransferase (HGSNAT) deficiency, an enzyme which typically catalyzes the transmembrane acetylation of heparan sulfate, a basement membrane component. When the gene encoding this enzyme is mutated, it cannot perform the processing of heparan sulfate, leading to un-acetylated heparan sulfate build-up in the lysosomes of cells, causing a storage disorder. This defect has been studied primarily in brain and liver cells, but its effect on the structural integrity of the glomerulus is poorly known. The present study focuses on the effect of Hgsnat gene inactivation and heparan sulfate toxicity on the integrity of the renal corpuscle. This cortical structure was chosen because of its abundance of basement membranes and heparan sulfate as well as the renal corpuscle’s physiological importance in glomerular filtration. Light microscopy, electron microscopy, and immunocytochemistry of genetically modified mice revealed a buildup of lysosomes in the podocytes, suggesting that these cells are responsible for the processing of glomerular basement membranes
Open Access
Morphological studies of glomeruli in obstructive kidneys by confocal laser scanning microscopy and quick-freezing replica method
(Murcia : F. Hernández, 1998) Matsuda, A.; Terada, N.; Ueda, H.; Fuji, Y.; Tago, K.; Ueno, A.; Ohno, S.
Morphological changes of glomeruli in obstructive kidneys were studied by using confocal laser scanning microscopy (CLSM), and quick-freezing and deep-etching (QF-DE) method. Twenty-one rabbits were divided into three groups, consisting of control, 6-hr bilateral ureteral obstruction (BUO) and 24-hr BUO. In the experimental groups, the attenuation of cell bodies, the lengthening and stretching of major processes, the cystic formation in the cytoplasm and the fusion of foot processes were observed on conventional ultrathin sections. These changes in the 24-hr BUO group were more clearly observed than those in the 6-hr BUO group. By the CLSM, cell bodies and foot processes of podocytes in the experimental groups were more intensely immunostained with anti-a-tubulin antibody and phalloidin-FITC. By the QF-DE method, cytoskeletons in the podocyte cell bodies and major processes were composed of numerous intermediate filaments, but distinct changes of actin filaments and microtubules were not observed in the control and experimental groups. Considering the physiological changes in BUO, the mechanical stress appeared to be brought about by hemodynamic factors rather than the change of intratubular pressure, resembling the morphological changes in experimental animals with hyperfiltration and the homeostatic adaptation of podocytes under the BUO condition.
Open Access
p66Shc regulates podocyte autophagy in high glucose environment through the Notch-PTEN-PI3K/Akt/mTOR pathway
(Universidad de Murcia, Departamento de Biologia Celular e Histiologia, 2020) Zheng, Danna; Tao, Mei; Liang, Xudong; Li, Yiwen; Jin, Juan; He, Qiang
Background and aims. Autophagy has been found to be involved in podocyte injury, which is a key factor in the progression of diabetic kidney disease (DKD). p66Shc is an important protein adaptor that regulates production of reactive oxygen species (ROS) and induction of apoptosis, and is a novel biomarker for oxidative damage of renal tubules. Our preliminary studies showed that p66Shc expression in podocytes of DKD patients is increased, while autophagic flux and podocyte number is decreased in DKD patients. The mechanism by which p66Shc may regulate podocyte autophagy and injury remains unknown. The present study aimed to investigate the molecular function of p66Shc under high glucose condition and its possible therapeutic utility in DKD. Methods. We histologically evaluated kidney injury in a streptozocin (STZ)-induced mouse model of diabetes using HE, PAS, PASM, and Masson staining and assessed glomerular structure by transmission electron microscopy. The apoptosis rate of high glucose- treated podocytes was assessed by TUNEL and Annexin V/PI staining. Markers of podocyte autophagy were measured by immunofluorescence and western blotting. DHE/ET fluorescence quantification was used for ROS detection and quantification. Results. Urine creatinine, serum creatinine, urinary microalbumin, and p66Shc expression were significantly increased in STZ-induced diabetic mice. Cultured MPC5 podocytes subjected to high glucose showed reduced viability, and p66Shc overexpression further accelerated apoptosis. p66Shc knockdown enhanced HG-induced autophagy, while p66Shc overexpression reduced the expression of PTEN and increased the expression of mTOR and phospho-mTOR. LC3 protein expression was higher in cells with p66Shc knockdown, indicating that activation of p66Shc inhibits podocyte autophagy. DAPT, an inhibitor of the Notch pathway, downregulated the expression of p66Shc. Conclusion. These findings indicate that p66Shc inhibits podocyte autophagy and induces apoptosis through the Notch -PTEN-PI3K/Akt/ mTOR signaling pathway in high glucose environment, providing novel evidence for its potential role in DKD treatment
Open Access
Pathological correlations between podocyte injuries and renal functions in canine and feline chronic kidney diseases
(F. Hernández y J.F. Madrid. Murcia: Universidad de Murcia, Departamento de Biología Celular e Histología., 2011) Ichii, Osamu; Yabuki, Akira; Sasaki, Nobuya; Otsuka, Saori; Ohta, Hiroshi; Yamasaki, Masahiro; Takiguchi, Mitsuyoshi; Namiki, Yuka; Hashimoto, Yoshiharu; Endoh, Daiji; Kon, Yasuhiro
Podocytes cover the glomerulus and their adjacent foot processes form a principal barrier called the slit diaphragm. Podocyte dysfunctions, including podocyte loss and slit diaphragm disruptions, induce chronic kidney diseases (CKD). In this study, we analyzed the correlations between podocyte injuries and renal dysfunctions in domestic carnivores. Dogs and cats were divided into normal and CKD groups according to renal histopathology and plasma creatinine values. Immunostaining results showed that linear reactions of slit diaphragm molecules, e.g., nephrin, podocin, and ACTN4, were parallel to glomerular capillaries in all animals. However, in dogs, reactions of nephrin and ACTN4 were changed to a granular pattern in the CKD group, and their intensities significantly decreased with the number of podocytes in the glomerulus. Moreover, the expression of nephrin and ACTN4 negatively correlated with creatinine. Real-time PCR analysis showed that nephrin mRNA expression in the kidneys of CKD dogs was significantly lower than that in normal animals, and negatively correlated with creatinine. Although no significant correlation between renal dysfunction and podocyte injury was detected in cats, histoplanimetric scores of tubulointerstitial lesions in CKD cats were higher than those in both normal cats and diseased dogs. Furthermore, mRNAs of WT1 and SD molecules were detected in urine from CKD animals. In conclusion, podocyte injuries such as podocytopenia and decreased expression of nephrin and ACTN4 in the glomerulus were more strongly correlated with renal dysfunction in dogs than in cats. These findings suggest that the CKD pathogenesis, especially susceptibilities to podocyte injuries, differed between dogs and cats.
Open Access
Podocyte involvement in the pathogenesis of preterm-related long-term chronic kidney disease
(Universidad de Murcia, Departamento de Biologia Celular e Histiologia, 2024) Zhang, Lulu; Zheng, Jun; Ding, Fangrui
With the continuous advancement of neonatal intensive care technology, the survival rate of preterm infants is gradually increasing. However, this improvement in survival is accompanied by long-term prognostic implications in various systems. In the field of renal diseases, current epidemiological data indicate that preterm birth is a significant risk factor for the development of long-term chronic kidney disease (CKD). This not only imposes an economic burden on patients families but also severely impacts their quality of life. Understanding the underlying mechanisms involved in this process could offer potential strategies for early prevention and management of CKD. Although the nephron number hypothesis is currently widely accepted as a mechanism, there has been limited exploration regarding podocytes - one of the most important structures within nephrons - in relation to long-term CKD associated with preterm birth. Therefore, this review aims to summarize current knowledge on how prematurity influences CKD development overall, while specifically focusing on our current understanding of podocytes in relation to prematurity
Open Access
The novel involvement of podocyte autophagic activity in the pathogenesis of lupus nephritis
(Universidad de Murcia. Departamento de Biología Celular e Histología, 2018) Jin, Juan; Ye, Meiyu; Zhao, Li; Zou, Wenli; Shen, Wei; Zhang, Hongjuan; Gong, Jianguang; He, Qiang
Background. Lupus nephritis (LN) is one of the most common and severe complications in Systemic lupus erythematosus patients, and the mechanism underlining the pathogenesis of LN is still unknown. Autophagy plays vital roles in maintaining cell homeostasis and is involved in the pathogenesis of many diseases. In this study, we investigated the role of autophagy in the progression of LN. Methods. Autophagic activities in podocytes of both LN patients (Class IV and V) and mice were evaluated. Podocytes were observed by electron microscopy, and autophagic activity was evaluated by immunofluorescence staining and western blot analysis. Apoptotic activity was evaluated by immunohistochemistry, TUNEL assays and flow cytometric analysis. Results. Significantly greater podocyte injury and discrepant autophagic levels were observed in LN patients. Differentiated mouse podocytes in the LN group showed reduced nephrin expression and increased apoptosis, as well as significantly higher levels of apoptosis-related proteins (cleaved caspase-3 and Bax). In the mice LN group, the increased number of autophagosomes was accompanied by increased LC3- II/LC3-I ratios and decreased p62, suggesting increased autophagic and apoptotic activity in podocytes. Blockade of autophagic activity by 3-MA or siRNAmediated silencing of Atg5 resulted in decreases in LC3- II/LC3-I ratios, podocyte apoptosis and damage in the mice LN group. Futhermore, Rapamycin treatment increased LC3-II/LC3-I ratios, and enhanced LNinduced apoptosis in podocyte from modal animal. Conclusions. This study demonstrates that autophagic activity of podocytes is a crucial factor in renal injury by directly affecting the function of podocyte; thus, inhibiting this activity during the early stages of LN is implicated as a potential therapeutic strategy for delaying the progression of LN. Also, clinical application in LN needs to consider patients’ pathological type and drugs’ comprehensive effectiveness.
Open Access
Tripterygium glycoside protects diabetic kidney disease mouse serum-induced podocyte injury by upregulating autophagy and downregulating β-arrestin-1
(Universidad de Murcia. Departamento de Biología Celular e Histología, 2019) Zhan, Huifang; Jin, Juan; Liang, Shikai; Zhao, Li; Gong, Jianguang; He, Qiang
Background. Diabetic kidney disease (DKD), one of the most common causes of end-stage renal disease (ESRD), remains prevalent in many populations. Podocyte loss and apoptosis play a crucial role in the progression of DKD. Tripterygium glycoside (TG), a widely used Chinese herb, exerted comprehensive protective effects on preventing DKD progression. This study was performed to assess the podocyte protective effect of tripterygium glycoside on DKD by the potential role of activation of autophagy and downregulating βarrestin-1. Methods. Tripterygium glycoside and small interfering RNA (siRNA) of β-arrestin-1 were added to 10% db/db mice high-glucose serum induced podocytes in vitro. Autophagic activity was evaluated by transmission electronic microscopy, immunofluorescence staining and western blot analysis. Apoptotic activity was evaluated by Annexin V-FITC/PI flow cytometric analysis. The levels of nephrin and podocin, a marker protein of podocytes, were examined using western blot analysis. Results. Significantly ameliorated podocyte apoptosis, increased nephrin and podocin levels and inhibited expression of β-arrestin-1 were observed after pretreatment of tripterygium glycoside in DKD mouse serum treated podocytes. Significantly higher levels of autophagic activity were also observed. Silencing βarrestin-1 upregulated autophagic activity and ameliorated podocyte apoptosis. Silencing β-arrestin-1 in combination with tripterygium glycoside enhanced the levels of LC3-II and LC3-II/LC3-I ratios and reduced the expression of p62. Finally, we observed a notable reduction in podocyte apoptotic rate in DKD serum + siRNA-β-arrestin-1 + TG group compared to DKD serum + siRNA-β-arrestin-1 group, and upregulated protein levels of nephrin and podocin compared to treatment with siRNA-β-arrestin-1 only. Conclusions. This study demonstrated that tripterygium glycoside provided protection against podocyte injury induced by high-glucose serum, and that this effect was mediated by the concomitant activation of autophagy and downregulation of β-arrestin-1.

Browsing by Subject "Podocyte"

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