scholarly journals PKC-α Triggers EGFR Ubiquitination, Endocytosis and ERK Activation in Podocytes Stimulated with High Glucose

2017 ◽  
Vol 42 (1) ◽  
pp. 281-294 ◽  
Author(s):  
Chun-Tao Lei ◽  
Yan-Hong Wei ◽  
Hui Tang ◽  
Qian Wen ◽  
Chen Ye ◽  
...  
Keyword(s):  
Lipid Raft ◽  
High Glucose ◽  
Growth Factor Receptor ◽  
In Vitro Study ◽  
Diabetic Rats ◽  
Kidney Cortex ◽  
Podocyte Injury ◽  
Erk Activation ◽  
Signaling Activation

Background: Protein Kinase C-α (PKC-α) and epidermal growth factor receptor (EGFR) are both involved in diabetic kidney disease; however, the connection between these two proteins during high glucose-induced podocyte injury remains uncertain. Methods: Diabetes was induced in SD rats by streptozotocin (STZ). Fourteen days later, the kidney cortex was removed and subjected to plasma membrane isolation and lipid raft fractionation. In vitro study human podocyte cell line was differentiated and subjected to various treatments. The levels of membranous protein and endocytosis were assessed by biotinylation and sodium 2-mercaptoethane sulfonate (MesNa) treatment. Gö6976 and PYR-41 were used as inhibitors of PKC-α and ubiquitin activating E1 enzyme, respectively. Results: In diabetic rats, the abundance of PKC-α in the membranous fraction and the lipid raft domain is elevated, whereas the EGFR level is reduced. Consistently, in vitro high glucose treated podocytes, membranous EGFR is downregulated with increased PKC-α. Furthermore, the ubiquitination and endocytosis of EGFR are enhanced accompanied by extracellular signal–regulated kinase (ERK) signaling activation and podocyte damage during hyperglycemia. However, these processes can be ameliorated by inhibition of either PKC-α or ubiquitin activating E1 enzyme. Conclusion: During hyperglycemia, PKC-α mediates podocytic EGFR ubiquitination, endocytosis from cell surface and the subsequent ERK activation, which contributes to podocyte injury.

scholarly journals Mfn2 Regulates High Glucose-Induced MAMs Dysfunction and Apoptosis in Podocytes via PERK Pathway

2021 ◽  
Vol 9 ◽  
Author(s):  
Yun Cao ◽  
Zhaowei Chen ◽  
Jijia Hu ◽  
Jun Feng ◽  
Zijing Zhu ◽  
...  
Keyword(s):  
Mitochondrial Dysfunction ◽  
High Glucose ◽  
Diabetic Rats ◽  
Mitochondrial Morphology ◽  
Podocyte Injury ◽  
Unfolded Protein ◽  
Mitochondrial Functions ◽  
Protein Response ◽  
Apoptotic Effects

The endoplasmic reticulum (ER) stress and mitochondrial dysfunction in high glucose (HG)-induced podocyte injury have been demonstrated to the progression of diabetic kidney disease (DKD). However, the pathological mechanisms remain equivocal. Mitofusin2 (Mfn2) was initially identified as a dynamin-like protein involved in fusing the outer mitochondrial membrane (OMM). More recently, Mfn2 has been reported to be located at the ER membranes that contact OMM. Mitochondria-associated ER membranes (MAMs) is the intercellular membrane subdomain, which connects the mitochondria and ER through a proteinaceous tether. Here, we observed the suppression of Mfn2 expression in the glomeruli and glomerular podocytes of patients with DKD. Streptozotocin (STZ)-induced diabetic rats exhibited abnormal mitochondrial morphology and MAMs reduction in podocytes, accompanied by decreased expression of Mfn2 and activation of all three unfolded protein response (UPR) pathways (IRE1, ATF6, and PERK). The HG-induced mitochondrial dysfunction, MAMs reduction, and increased apoptosis in vitro were accompanied by the downregulation of Mfn2 and activation of the PERK pathway. Mfn2 physically interacts with PERK, and HG promotes a decrease in Mfn2-PERK interaction. In addition, Mfn2-silenced podocytes showed mitochondrial dysfunction, MAMs reduction, activation of PERK pathway, and increased apoptosis. Conversely, all these effects of HG stimulation were alleviated significantly by Mfn2 overexpression. Furthermore, the inhibition of PERK phosphorylation protected mitochondrial functions but did not affect the expression of Mfn2 in HG-treated podocytes. Therefore, this study confirmed that Mfn2 regulates the morphology and functions of MAMs and mitochondria, and exerts anti-apoptotic effects on podocytes by inhibiting the PERK pathway. Hence, the Mfn2-PERK signaling pathway may be a new therapeutic target for preventing podocyte injury in DKD.

scholarly journals The antioxidant silybin prevents high glucose-induced oxidative stress and podocyte injury in vitro and in vivo

2013 ◽  
Vol 305 (5) ◽  
pp. F691-F700 ◽  
Author(s):  
Khaled Khazim ◽  
Yves Gorin ◽  
Rita Cassia Cavaglieri ◽  
Hanna E. Abboud ◽  
Paolo Fanti
Keyword(s):  
Diabetic Nephropathy ◽  
Nadph Oxidase ◽  
High Glucose ◽  
Drop Out ◽  
Superoxide Production ◽  
Kidney Cortex ◽  
Active Constituent ◽  
Podocyte Injury

Podocyte injury, a major contributor to the pathogenesis of diabetic nephropathy, is caused at least in part by the excessive generation of reactive oxygen species (ROS). Overproduction of superoxide by the NADPH oxidase isoform Nox4 plays an important role in podocyte injury. The plant extract silymarin is attributed antioxidant and antiproteinuric effects in humans and in animal models of diabetic nephropathy. We investigated the effect of silybin, the active constituent of silymarin, in cultures of mouse podocytes and in the OVE26 mouse, a model of type 1 diabetes mellitus and diabetic nephropathy. Exposure of podocytes to high glucose (HG) increased 60% the intracellular superoxide production, 90% the NADPH oxidase activity, 100% the Nox4 expression, and 150% the number of apoptotic cells, effects that were completely blocked by 10 μM silybin. These in vitro observations were confirmed by similar in vivo findings. The kidney cortex of vehicle-treated control OVE26 mice displayed greater Nox4 expression and twice as much superoxide production than cortex of silybin-treated mice. The glomeruli of control OVE26 mice displayed 35% podocyte drop out that was not present in the silybin-treated mice. Finally, the OVE26 mice experienced 54% more pronounced albuminuria than the silybin-treated animals. In conclusion, this study demonstrates a protective effect of silybin against HG-induced podocyte injury and extends this finding to an animal model of diabetic nephropathy.

scholarly journals Effect of Tongxinluo on Nephrin Expression via Inhibition of Notch1/Snail Pathway in Diabetic Rats

2015 ◽  
Vol 2015 ◽  
pp. 1-11 ◽  
Author(s):  
Fangqiang Cui ◽  
Dawei Zou ◽  
Yanbin Gao ◽  
Na Zhang ◽  
Jinyang Wang ◽  
...  
Keyword(s):  
Diabetic Nephropathy ◽  
Molecular Mechanism ◽  
High Glucose ◽  
Diabetic Rats ◽  
In Vitro Studies ◽  
Podocyte Injury ◽  
Snail Expression ◽  
Renal Structure

Podocyte injury is an important mechanism of diabetic nephropathy (DN). Accumulating evidence suggests that nephrin expression is decreased in podocyte in DN. Moreover, it has been demonstrated that tongxinluo (TXL) can ameliorate renal structure disruption and dysfunction in DN. However, the effect of TXL on podocyte injury in DN and its molecular mechanism is unclear. In order to explore the effect of TXL on podocyte injury and its molecular mechanism in DN, our in vivo and in vitro studies were performed. Our results showed that TXL increased nephrin expression in diabetic rats and in high glucose cultured podocyte. Meanwhile, TXL decreased ICN1 (the intracellular domain of notch), HES1, and snail expression in podocyte in vivo and in vitro. More importantly, we found that TXL protected podocyte from injury in DN. The results demonstrated that TXL inhibited the activation of notch1/snail pathway and increased nephrin expression, which may be a mechanism of protecting effect on podocyte injury in DN.

scholarly journals Increased long noncoding RNA maternally expressed gene 3 contributes to podocyte injury induced by high glucose through regulation of mitochondrial fission

2020 ◽  
Vol 11 (9) ◽  
Author(s):  
Qiongxia Deng ◽  
Ruowei Wen ◽  
Sirui Liu ◽  
Xiaoqiu Chen ◽  
Shicong Song ◽  
...  
Keyword(s):  
High Glucose ◽  
Noncoding Rna ◽  
Diabetic Kidney Disease ◽  
Mitochondrial Fission ◽  
Diabetic Mice ◽  
Podocyte Injury ◽  
Mitochondrial Translocation ◽  
Maternally Expressed Gene 3

Abstract Excessive mitochondrial fission plays a key role in podocyte injury in diabetic kidney disease (DKD), and long noncoding RNAs (lncRNAs) are important in the development and progression of DKD. However, lncRNA regulation of mitochondrial fission in podocytes is poorly understood. Here, we studied lncRNA maternally expressed gene 3 (Meg3) in mitochondrial fission in vivo and in vitro using human podocytes and Meg3 podocyte-specific knockdown mice. Expression of lncRNA Meg3 in STZ-induced diabetic mice was higher, and correlated with the number of podocytes. Excessive mitochondrial fission of podocytes and renal histopathological and physiological parameters were improved in podocyte-specific Meg3 knockdown diabetic mice. Elongated mitochondria with attenuated podocyte damage, as well as mitochondrial translocation of dynamin-related protein 1 (Drp1), were decreased in Meg3 knockout podocytes. By contrast, increased fragmented mitochondria, podocyte injury, and Drp1 expression and phosphorylation were observed in lncRNA Meg3-overexpressing podocytes. Treatment with Mdivi1 significantly blunted more fragmented mitochondria and reduced podocyte injury in lncRNA Meg3-overexpressing podocytes. Finally, fragmented mitochondria and Drp1 mitochondrial translocation induced by high glucose were reduced following treatment with Mdivi1. Our data show that expression of Meg3 in podocytes in both human cells and diabetic mice was higher, which regulates mitochondrial fission and contributes to podocyte injury through increased Drp1 and its translocation to mitochondria.

scholarly journals High Glucose-Mediated Cytokine Regulation in Gingival Fibroblasts and THP-1 Macrophage: a Possible Mechanism of Severe Periodontitis with Diabetes

2018 ◽  
Vol 50 (3) ◽  
pp. 973-986 ◽  
Author(s):  
Jung-Hwan Lew ◽  
Koji Naruishi ◽  
Yukari Kajiura ◽  
Yasufumi Nishikawa ◽  
Takahisa Ikuta ◽  
...  
Keyword(s):  
High Glucose ◽  
Gingival Crevicular Fluid ◽  
In Vitro Study ◽  
Inflammatory Factors ◽  
Diabetic Patients ◽  
Gingival Fibroblasts ◽  
Cross Sectional ◽  
Periodontal Tissues ◽  
Severe Periodontitis

Background/Aims: Diabetic patients are susceptible to severe periodontitis, but the precise mechanism is not fully understood. Aim of this study was to explore the biological pathogenesis of severe periodontitis in diabetic patients focusing on the crosstalk of human gingival fibroblasts (HGFs) and macrophages. Methods: A total of 70 periodontitis patients with or without diabetes mellitus (DM) were enrolled, and the statistical relationships of diabetic conditions to the periodontal inflammatory parameters were examined by cross-sectional study. In in vitro study, HGFs cell line CRL-2014® (ATCC) and differentiated THP-1 macrophages were cultured with normal glucose (NG: 5.5 mM) or high glucose (HG: 25 mM) condition, and treated with indicated inflammatory factors such as calprotectin (CPT), interleukin (IL)-1β and IL-6. To examine the effects of HG on soluble IL-6 receptor (sIL-6R) production in THP-1 macrophages, the supernatants were collected and the sIL-6R levels were measured by ELISA. To examine the effects of HG on IL-1β or IL-6-induced matrix metalloproteinase (MMPs) production in HGFs, the supernatants were collected. Levels of MMP-1 and tissue inhibitor of MMP-1 (TIMP-1) were measured by ELISA. Finally, after conditioned medium (CM) from THP-1 macrophages cultured with NG or HG conditions was collected, HGFs were treated with the CM. The supernatants were collected 24 hours later and the levels of MMP-1 and TIMP-1 were measured. To examine the specific effects of IL-1β contained in CM on MMP-1 and TIMP-1 production in HGFs, IL-1 receptor antagonist (IL-1ra) was used. Results: There were statistical correlation between IL-1β and sIL-6R levels in gingival crevicular fluid (GCF) and HbA1c in periodontitis patients with DM (IL-1β: P=0.035, sIL-6R: P=0.040). HG and CPT significantly induced sIL-6R production in THP-1 macrophages. HG significantly enhanced IL-1β or IL-6/sIL-6R-induced MMP-1 production in HGFs. The increase of MMP-1 by both IL-1β and IL-6/sIL-6R was significantly inhibited by specific ERK or IκB inhibitors. Corresponding to the regulation of MMP-1 production, HG condition increased the phosphorylation of p44/42 MAPK and IκBα in HGFs treated with IL-1β or IL-6/sIL-6R. Finally, MMP-1 production in HGFs cultured with HG increased significantly by CM from THP-1 macrophages cultured with HG. The induction of MMP-1 by the CM from THP-1 macrophages cultured with HG was significantly inhibited by dose dependent of IL-1ra in HGFs cultured with HG. Conclusion: Diabetic conditions such as HG induce IL-1β and sIL-6R production from macrophages in inflammatory periodontal tissues and may exacerbate the periodontitis synergistically via MMP-1 production from HGFs.

scholarly journals Hydroxytyrosol Promotes Proliferation of Human Schwann Cells: An In Vitro Study

2020 ◽  
Vol 17 (12) ◽  
pp. 4404
Author(s):  
Khidhir Kamil ◽  
Muhammad Dain Yazid ◽  
Ruszymah Bt Hj Idrus ◽  
Jaya Kumar
Keyword(s):  
Cell Cycle ◽  
Protein Expression ◽  
Schwann Cells ◽  
Growth Factor Receptor ◽  
In Vitro Study ◽  
Cell Cycle Analysis ◽  
Proliferation Index ◽  
Proliferation Markers ◽  
Diphenyltetrazolium Bromide

Recent advances in phytomedicine have explored some potential candidates for nerve regeneration, including hydroxytyrosol (HT). This study was undertaken to explore the potential effects of HT on human Schwann cells’ proliferation. Methods: The primary human Schwann cell (hSC) was characterized, and the proliferation rate of hSC supplemented with various concentrations of HT was determined via 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) assay. Cell cycle analysis and protein expression of glial fibrillary acidic protein (GFAP) and p75 nerve growth factor receptor (p75 NGFR) were evaluated via the immunofluorescence technique. Results: In vitro culture of hSCs revealed spindle-like, bipolar morphology with the expression of specific markers of hSC. Hydroxytyrosol at 10 and 20 ng/mL significantly increased the proliferation of hSCs by 30.12 ± 5.9% and 47.8 ± 6.7% compared to control (p < 0.05). Cell cycle analysis showed that HT-treated hSCs have a higher proliferation index (16.2 ± 0.2%) than the control (12.4 ± 0.4%) (p < 0.01). In addition, HT significantly increased the protein expression of GFAP and p75NGFR (p < 0.05). Conclusion: HT stimulates the proliferation of hSCs in vitro, indicated by a significant increase in the hSC proliferation index and protein expression of hSCs’ proliferation markers, namely p75 NGFR and GFAP.

scholarly journals Ginsenoside Rg1 Alleviates Podocyte Injury Induced by Hyperlipidemia via Targeting the mTOR/NF-κB/NLRP3 Axis

2020 ◽  
Vol 2020 ◽  
pp. 1-14
Author(s):  
Tao Wang ◽  
Yanbin Gao ◽  
Rongchuan Yue ◽  
Xiaolei Wang ◽  
Yimin Shi ◽  
...  
Keyword(s):  
Mammalian Target Of Rapamycin ◽  
Diabetic Rats ◽  
Therapeutic Effects ◽  
Ginsenoside Rg1 ◽  
Podocyte Injury ◽  
Therapeutic Function ◽  
Polymerase Chain ◽  
Underlying Mechanisms

Background. Podocyte injury plays an important role in diabetic nephropathy (DN). The aim of this study was to determine the potential therapeutic effects of the ginsenoside Rg1 on hyperlipidemia-stressed podocytes and elucidate the underlying mechanisms. Methods. In vitro and in vivo models of DN were established as previously described, and the expression levels of relevant markers were analyzed by Western blotting, real-time Polymerase Chain Reaction (PCR), immunofluorescence, and immunohistochemistry. Results. Ginsenoside Rg1 alleviated pyroptosis in podocytes cultured under hyperlipidemic conditions, as well as in the renal tissues of diabetic rats, and downregulated the mammalian target of rapamycin (mTOR)/NF-κB pathway. In addition, Rg1 also inhibited hyperlipidemia-induced NLRP3 inflammasome in the podocytes, which was abrogated by the mTOR activator L-leucine (LEU). The antipyroptotic effects of Rg1 manifested as improved renal function in the DN rats. Conclusion. Ginsenoside Rg1 protects podocytes from hyperlipidemia-induced damage by inhibiting pyroptosis through the mTOR/NF-κB/NLRP3 axis, indicating a potential therapeutic function in DN.

scholarly journals Effects of Transplanting Bone Marrow Stromal Cells Transfected with CXCL13 on Fracture Healing of Diabetic Rats

2018 ◽  
Vol 49 (1) ◽  
pp. 123-133 ◽  
Author(s):  
Hui Jiang ◽  
Yicun Wang ◽  
Jia Meng ◽  
Shuo Chen ◽  
Jun Wang ◽  
...  
Keyword(s):  
Bone Marrow ◽  
Fracture Healing ◽  
Stromal Cells ◽  
High Glucose ◽  
Bone Marrow Stromal Cells ◽  
Diabetic Rats ◽  
Marrow Stromal Cells ◽  
Area Measurement ◽  
Mineral Density

Background/Aims: Diabetic fracture have poor treatment and serious complications. Therefore, how to treat diabetic fracture is receiving increasing attention. This study aimed to investigate the effects of transplanting CXCL13-stimulated bone marrow stromal cells (BMSCs) on the fracture healing in diabetic rats. Methods: In vitro, RT-PCR was employed to examine the expression of CXCL13 in BMSCs in high glucose environment. MTT assay and apoptosis assay were utilized to determine the effects of CXCL13 overexpression on the proliferation and apoptosis of BMSCs respectively. ALP staining was applied to detect the ALP activity. In vivo, CXCL13-stimulated BMSCs were transplanted into the fracture sites of diabetic rats. At the 1st week, 2nd weeks, 4th week and 6th week after the operation, bone mineral density (BMD) and callus area measurement, ELISA detection, and HE staining were performed to evaluate the fracture healing. Results: Low BMD and less area of callus in diabetic rats showed that the recovery after fracture was worse in diabetic rats than in non-diabetic rats. Meanwhile, the expression of CXCL13 in serum was lower in diabetic rats than in non-diabetic rats. Overexpression of CXCL13 promoted the proliferation of BMSCs in vitro high glucose environment. After BMSCs transfected with CXCL13 being transplanted into the fracture sites of diabetic rats, it was found that the fracture healing was enhanced and ALP expression in serum became higher. HE staining results further verified the effects of transplantation of BMSCs transfected with CXCL13 on fracture healing in diabetic rats. Conclusion: These finding indicated that CXCL13 may play a critical role in the process of fracture healing, which could provide a deeper insight into molecular targets for the fracture healing in diabetic people.

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