AGE-Induced Suppression of EZH2 Mediates Injury of Podocytes by Reducing H3K27me3

2020 ◽  
Vol 51 (9) ◽  
pp. 676-692
Author(s):  
Marita Liebisch ◽  
Gunter Wolf
Keyword(s):  
Diabetic Kidney Disease ◽  
Metabolic Memory ◽  
Central Feature ◽  
Podocyte Injury ◽  
Histone 3 ◽  
Chronic Hyperglycemia ◽  
Ezh2 Expression ◽  
Glycation End Products

Background: Chronic hyperglycemia, a pivotal feature of diabetes mellitus (DM), initiates the formation of advanced glycation end products (AGEs) and the dysregulation of epigenetic mechanisms, which may cause injury to renal podocytes, a central feature of diabetic kidney disease (DKD). Previous data of our group showed that AGEs significantly reduce the expression of NIPP1 (nuclear inhibitor of protein phosphatase 1) in podocytes in vitro as well as in human and murine DKD. NIPP1 was shown by others to interact with enhancer of zeste homolog 2 (EZH2), which catalyzes the repressive methylation of H3K27me3 on histone 3. Therefore, we hypothesized that AGEs can directly induce epigenetic changes in podocytes. Methods: We analyzed the relevance of AGEs on EZH2 expression and activity in a murine podocyte cell line. Cells were treated with 5 mg/mL glycated BSA for 24 h. To determine the meaning of EZH2 suppression, EZH2 activity was inhibited by incubating the cells with the pharmacological methyltransferase inhibitor 3-deazaneplanocin A; EZH2 expression was repressed with siRNA. mRNA expression was analyzed with real-time PCR, and protein expression with Western blot. EZH2 expression and level of H3K27 trimethylation in podocytes of diabetic db/db mice, a mouse model for type 2 DM, were analyzed using immunofluorescence. Results: Our data demonstrated that AGEs decrease EZH2 expression in podocytes and consequently reduce H3K27me3. This suppression of EZH2 mimicked the AGE effects and caused an upregulated expression of pathological factors that contribute to podocyte injury in DKD. In addition, analyses of db/db mice showed significantly reduced H3K27me3 and EZH2 expression in podocytes. Moreover, the suppression of NIPP1 and EZH2 showed similar effects regarding podocyte injury. Conclusions: Our studies provide a novel pathway how AGEs contribute to podocyte injury and the formation of the so-called metabolic memory in DKD.

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 RAGE Mediates Cholesterol Efflux Impairment in Macrophages Caused by Human Advanced Glycated Albumin

2020 ◽  
Vol 21 (19) ◽  
pp. 7265
Author(s):  
Adriana Machado-Lima ◽  
Raquel López-Díez ◽  
Rodrigo Tallada Iborra ◽  
Raphael de Souza Pinto ◽  
Gurdip Daffu ◽  
...  
Keyword(s):  
Cholesterol Efflux ◽  
Glycated Albumin ◽  
Wild Type ◽  
Intracellular Lipid ◽  
Glycation End Products ◽  
Macrophage Cholesterol Efflux ◽  
Cellular Cholesterol Efflux

We addressed the involvement of the receptor for advanced glycation end products (RAGE) in the impairment of the cellular cholesterol efflux elicited by glycated albumin. Albumin was isolated from type 1 (DM1) and type 2 (DM2) diabetes mellitus (HbA1c > 9%) and non-DM subjects (C). Moreover, albumin was glycated in vitro (AGE-albumin). Macrophages from Ager null and wild-type (WT) mice, or THP-1 transfected with siRNA-AGER, were treated with C, DM1, DM2, non-glycated or AGE-albumin. The cholesterol efflux was reduced in WT cells exposed to DM1 or DM2 albumin as compared to C, and the intracellular lipid content was increased. These events were not observed in Ager null cells, in which the cholesterol efflux and lipid staining were, respectively, higher and lower when compared to WT cells. In WT, Ager, Nox4 and Nfkb1, mRNA increased and Scd1 and Abcg1 diminished after treatment with DM1 and DM2 albumin. In Ager null cells treated with DM-albumin, Nox4, Scd1 and Nfkb1 were reduced and Jak2 and Abcg1 increased. In AGER-silenced THP-1, NOX4 and SCD1 mRNA were reduced and JAK2 and ABCG1 were increased even after treatment with AGE or DM-albumin. RAGE mediates the deleterious effects of AGE-albumin in macrophage cholesterol efflux.

scholarly journals Mice with Type 2 Diabetes Present Significant Alterations in Their Tissue Biomechanical Properties and Histological Features

Biomedicines ◽  
2021 ◽  
Vol 10 (1) ◽  
pp. 57
Author(s):  
Tânia B. Cruz ◽  
Filomena A. Carvalho ◽  
Paulo N. Matafome ◽  
Raquel A. Soares ◽  
Nuno C. Santos ◽  
...  
Keyword(s):  
Type 2 Diabetes ◽  
Adipose Tissue ◽  
Biomechanical Properties ◽  
Diabetic Mice ◽  
Force Microscopy ◽  
Chronic Hyperglycemia ◽  
Biomimetic Scaffolds ◽  
Patient Morbidity

Type 2 diabetes mellitus (T2DM) is a complex metabolic disease often associated with severe complications that may result in patient morbidity or death. One T2DM etiological agent is chronic hyperglycemia, a condition that induces damaging biological processes, including impactful extracellular matrix (ECM) modifications, such as matrix components accumulation. The latter alters ECM stiffness, triggering fibrosis, inflammation, and pathological angiogenesis. Hence, studying ECM biochemistry and biomechanics in the context of T2DM, or obesity, is highly relevant. With this in mind, we examined both native and decellularized tissues of obese B6.Cg-Lepob/J (ob/ob) and diabetic BKS.Cg-Dock7m+/+LeprdbJ (db/db) mice models, and extensively investigated their histological and biomechanical properties. The tissues analyzed herein were those strongly affected by diabetes—skin, kidney, adipose tissue, liver, and heart. The referred organs and tissues were collected from 8-week-old animals and submitted to classical histological staining, immunofluorescence, scanning electron microscopy, rheology, and atomic force microscopy. Altogether, this systematic characterization has identified significant differences in the architecture of both ob/ob and db/db tissues, namely db/db skin presents loose epidermis and altered dermis structure, the kidneys have clear glomerulopathy traits, and the liver exhibits severe steatosis. The distribution of ECM proteins also pinpoints important differences, such as laminin accumulation in db/db kidneys and decreased hyaluronic acid in hepatocyte cytoplasm in both obese and diabetic mice. In addition, we gathered a significant set of data showing that ECM features are maintained after decellularization, making these matrices excellent biomimetic scaffolds for 3D in vitro approaches. Importantly, mechanical studies revealed striking differences between tissue ECM stiffness of control (C57BL/6J), obese, and diabetic mice. Notably, we have unveiled that the intraperitoneal adipose tissue of diabetic animals is significantly stiffer (G* ≈ 10,000 Pa) than that of ob/ob or C57BL/6J mice (G* ≈ 3000–5000 Pa). Importantly, this study demonstrates that diabetes and obesity selectively potentiate severe histological and biomechanical alterations in different matrices that may impact vital processes, such as angiogenesis, wound healing, and inflammation.

scholarly journals Advanced Glycation End Products Predict Loss of Renal Function and Correlate With Lesions of Diabetic Kidney Disease in American Indians With Type 2 Diabetes

Diabetes ◽  
2016 ◽  
Vol 65 (12) ◽  
pp. 3744-3753 ◽  
Author(s):  
Pierre-Jean Saulnier ◽  
Kevin M. Wheelock ◽  
Scott Howell ◽  
E. Jennifer Weil ◽  
Stephanie K. Tanamas ◽  
...  
Keyword(s):  
Type 2 Diabetes ◽  
Renal Function ◽  
Kidney Disease ◽  
American Indians ◽  
Advanced Glycation End Products ◽  
Diabetic Kidney Disease ◽  
Advanced Glycation ◽  
Glycation End Products ◽  
End Products

scholarly journals Effects of metabolic memory on inflammation and fibrosis associated with diabetic kidney disease: an epigenetic perspective

2021 ◽  
Vol 13 (1) ◽  
Author(s):  
Wen Zheng ◽  
Jia Guo ◽  
Zhang-Suo Liu
Keyword(s):  
Kidney Disease ◽  
Environmental Factors ◽  
Diabetic Kidney Disease ◽  
Early Recognition ◽  
Epigenetic Modifications ◽  
Metabolic Memory ◽  
Diabetic Patients ◽  
Diabetic Kidney

AbstractDiabetic kidney disease (DKD) is one of the most common microvascular complication of both type 1 (T1DM) and type 2 diabetes mellitus (T2DM), and the leading cause of end-stage renal disease (ESRD) worldwide. Persistent inflammation and subsequent chronic fibrosis are major causes of loss of renal function, which is associated with the progression of DKD to ESRD. In fact, DKD progression is affected by a combination of genetic and environmental factors. Approximately, one-third of diabetic patients progress to develop DKD despite intensive glycemic control, which propose an essential concept “metabolic memory.” Epigenetic modifications, an extensively studied mechanism of metabolic memory, have been shown to contribute to the susceptibility to develop DKD. Epigenetic modifications also play a regulatory role in the interactions between the genes and the environmental factors. The epigenetic contributions to the processes of inflammation and fibrogenesis involved in DKD occur at different regulatory levels, including DNA methylation, histone modification and non-coding RNA modulation. Compared with genetic factors, epigenetics represents a new therapeutic frontier in understanding the development DKD and may lead to therapeutic breakthroughs due to the possibility to reverse these modifications therapeutically. Early recognition of epigenetic events and biomarkers is crucial for timely diagnosis and intervention of DKD, and for the prevention of the progression of DKD to ESRD. Herein, we will review the latest epigenetic mechanisms involved in the renal pathology of both type 1 (T1DN) and type 2 diabetic nephropathy (T2DN) and highlight the emerging role and possible therapeutic strategies based on the understanding of the role of epigenetics in DKD-associated inflammation and fibrogenesis.

scholarly journals Estimation and correlation of sirtuin1 with Carboxy Methyl Lysine in type 2 diabetic and its microvascular complication

2020 ◽  
Author(s):  
Sai Deepika ◽  
KN Shashidhar ◽  
A. Raveesha ◽  
C. Muninarayana
Keyword(s):  
Diabetes Mellitus ◽  
Type 2 Diabetes ◽  
Diabetic Nephropathy ◽  
Kidney Disease ◽  
Diabetic Kidney Disease ◽  
Microvascular Complication ◽  
Diabetic Kidney ◽  
Chronic Hyperglycemia ◽  
Group 3

Background: Increase in Diabetes Mellitus increases incidence of its Microvascular complications such as diabetic retinopathy, diabetic kidney disease (DKD), neuropathy, stroke and cardio vascular diseases (CVD). Advanced glycation end products promotes Type 2 Diabetes to its major Microvascular complication; diabetic kidney disease or diabetic nephropathy leading to increase in expression of sirtuin1; a regulatory protein mediating deacetylation of histone proteins. In addition to diet and nutrition, environmental changes may increase incidence of disorders, one such factor considered in this study is Fluoride. Objective: Estimation of Sirtuin1 in type 2 diabetes mellitus and diabetic kidney disease and interpreting the outcome by diabetic profiling of patients with controls. Participants: 150 study subjects were recruited for this cross- sectional study divided into 3groups with 50 subjects in each group. Methods: Diabetic and renal profiling was carried by fully automated analyzer available in our hospital facility, eGFR was calculated, sirtuin1 and CML were measured by ELISA, serum and urine fluoride were estimated by Ion Selective Electrode. Results: Significant differences observed in FBS, PPBS and CML of deceased with controls. Least median of sirt1 was observed in diabetic nephropathy (36.9). Also, urine and serum fluoride levels were proportionally balanced in group 1& 2 in contrast with group 3 [0.28 (0.2- 0.54) & 0.2 (0.15- 0.26)]. Conclusion: Decrease in Sirtuin1 in group 3 may be due to chronic hyperglycemia and oxidative stress in diabetes hence, further research on large cohort may aid considering sirtuin1 as a biomarker or therapeutic target in aging disorders.

scholarly journals A New Italian Purple Corn Variety (Moradyn) Byproduct Extract: Antiglycative and Hypoglycemic In Vitro Activities and Preliminary Bioaccessibility Studies

Molecules ◽  
2020 ◽  
Vol 25 (8) ◽  
pp. 1958 ◽  
Author(s):  
Lucia Ferron ◽  
Raffaella Colombo ◽  
Barbara Mannucci ◽  
Adele Papetti
Keyword(s):  
In Vitro Digestion ◽  
Food Ingredient ◽  
Food Industries ◽  
Age Related ◽  
Glycation End Products ◽  
Enzymatic Systems ◽  
Key Factor ◽  
Typical Type

The reuse of byproducts from agricultural and food industries represents the key factor in a circular economy, whose interest has grown in the last two decades. Thus, the extraction of bioactives from agro-industrial byproducts is a potential source of valuable molecules. The aim of this work was to investigate the in vitro capacity of byproducts from a new Italian corn variety, named Moradyn, to inhibit the accumulation of advanced glycation end products (AGEs) involved in several chronic age-related disorders. In addition, the hypoglycemic effect of Moradyn was tested by in vitro enzymatic systems. A Moradyn phytocomplex and its purified anthocyanin fraction were able to inhibit fructosamine formation and exhibited antiglycative properties when tested using BSA-sugars and BSA-methylglyoxal assays. These properties could be attributed to the polyphenols, mainly anthocyanins and flavonols, detected by RP-HPLC-DAD-ESI-MSn. Finally, a Moradyn phytocomplex was submitted to a simulated in vitro digestion process to study its bioaccessibility. Moradyn could be considered as a promising food ingredient in the context of typical type 2 diabetes risk factors and the study will continue in the optimization of the ideal formulation to preserve its bioactivities from digestion.

scholarly journals Assessing the In Vitro Inhibitory Effects on Key Enzymes Linked to Type-2 Diabetes and Obesity and Protein Glycation by Phenolic Compounds of Lauraceae Plant Species Endemic to the Laurisilva Forest

Molecules ◽  
2021 ◽  
Vol 26 (7) ◽  
pp. 2023
Author(s):  
Vítor Spínola ◽  
Paula C. Castilho
Keyword(s):  
Type 2 Diabetes ◽  
Protein Glycation ◽  
Inhibitory Effects ◽  
Leaf Extracts ◽  
Key Enzymes ◽  
Glycation End Products ◽  
First Time ◽  
Diabetes And Obesity

Methanolic leaf extracts of four Lauraceae species endemic to Laurisilva forest (Apollonias barbujana, Laurus novocanariensis, Ocotea foetens and Persea indica) were investigated for the first time for their potential to inhibit key enzymes linked to type-2 diabetes (α-amylase, α-glucosidase, aldose reductase) and obesity (pancreatic lipase), and protein glycation. Lauraceae extracts revealed significant inhibitory activities in all assays, altough with different ability between species. In general, P. indica showed the most promissing results. In the protein glycation assay, all analysed extracts displayed a stronger effect than a reference compound: aminoguanidine (AMG). The in vitro anti-diabetic, anti-obesity and anti-glycation activities of analysed extracts showed correlation with their flavonols and flavan-3-ols (in particular, proanthocyanins) contents. These Lauraceae species have the capacity to assist in adjuvant therapy of type-2 diabetes and associated complications, through modulation of the activity of key metabolic enzymes and prevention of advanced glycation end-products (AGEs) formation.

scholarly journals Restoring mitochondrial superoxide levels with elamipretide (MTP-131) protects db/db mice against progression of diabetic kidney disease

2020 ◽  
Vol 295 (21) ◽  
pp. 7249-7260 ◽  
Author(s):  
Satoshi Miyamoto ◽  
Guanshi Zhang ◽  
David Hall ◽  
Peter J. Oates ◽  
Soumya Maity ◽  
...  
Keyword(s):  
Type 2 Diabetes ◽  
Kidney Disease ◽  
Diabetic Kidney Disease ◽  
Superoxide Production ◽  
Mesangial Matrix ◽  
Diabetic Kidney ◽  
Mitochondrial Superoxide ◽  
Chronic Hyperglycemia ◽  
Matrix Accumulation

Exposure to chronic hyperglycemia because of diabetes mellitus can lead to development and progression of diabetic kidney disease (DKD). We recently reported that reduced superoxide production is associated with mitochondrial dysfunction in the kidneys of mouse models of type 1 DKD. We also demonstrated that humans with DKD have significantly reduced levels of mitochondrion-derived metabolites in their urine. Here we examined renal superoxide production in a type 2 diabetes animal model, the db/db mouse, and the role of a mitochondrial protectant, MTP-131 (also called elamipretide, SS-31, or Bendavia) in restoring renal superoxide production and ameliorating DKD. We found that 18-week-old db/db mice have reduced renal and cardiac superoxide levels, as measured by dihydroethidium oxidation, and increased levels of albuminuria, mesangial matrix accumulation, and urinary H2O2. Administration of MTP-131 significantly inhibited increases in albuminuria, urinary H2O2, and mesangial matrix accumulation in db/db mice and fully preserved levels of renal superoxide production in these mice. MTP-131 also reduced total renal lysocardiolipin and major lysocardiolipin subspecies and preserved lysocardiolipin acyltransferase 1 expression in db/db mice. These results indicate that, in type 2 diabetes, DKD is associated with reduced renal and cardiac superoxide levels and that MTP-131 protects against DKD and preserves physiological superoxide levels, possibly by regulating cardiolipin remodeling.

MO635PRO-INFLAMMATORY CYTOKINES IL-6 AND IL-17 DISPLAY A PARTICULAR MOLECULAR PATTERN IN ASSOCIATION WITH DYSREGULATED MIRNAS IN PATIENTS WITH TYPE 2 DIABETES MELLITUS IN THE EARLY STAGES OF DIABETIC KIDNEY DISEASE

2021 ◽  
Vol 36 (Supplement_1) ◽  
Author(s):  
Golea Alina-Emanuela ◽  
Florica Gadalean ◽  
Adrian Vlad ◽  
Mihaela Vlad ◽  
Dumitrascu Victor ◽  
...  
Keyword(s):  
Regression Analysis ◽  
Inflammatory Cytokines ◽  
Diabetic Kidney Disease ◽  
Podocyte Injury ◽  
Serum Mirna ◽  
Type 2 Dm ◽  
Molecular Pattern ◽  
Multivariable Regression ◽  
Pro Inflammatory Cytokines

Abstract Background and Aims Glomerular injury and proximal tubule (PT) dysfunction have intricate mechanisms in diabetic kidney disease (DKD). Pro-inflammatory cytokines are involved in the initiation and progression of DKD through mediating the inflammatory response, both at glomerular and proximal tubular level. miRNAs are able to modulate cellular and biochemical functions, thus intervening in the pathogenesis of DKD. The aim of the study, performed on patients with type 2 diabetes mellitus (DM), was to evaluate selective pro-inflammatory cytokines in relation to biomarkers of podocyte lesion and of PT dysfunction. Particular molecular pathways, such as specific miRNA profiles operating in this relation, have also been studied. Method A number of 126 patients with type 2 DM, staged by albuminuria [39 normoalbuminuric – urinary albumin/creatinine ratio UACR)<30mg/g; 45 microalbuminuric–UACR-30–300mg/g; 42 macroalbuminuric–UACR>300mg/g], and 23 healthy control subjects were included in a cross-sectional study. All patients were evaluated concerning biomarkers of podocyte injury (nephrin, podocalyxin, synaptopodin) and of PT dysfunction [Kidney injury molecule-1(KIM-1), N-acetyl-beta-D-glucuronidase (NAG), alpha 1- microglobulin]. Also, serum and urinary levels of specific interleukins (IL-6, IL-17), serum cystatin C, and eGFR were determined. Serum and urinary miRNAs (miRNA-21, miRNA-124, miRNA-146a, miRNA-192) were assessed by RT-PCR. Results The biomarkers of podocyte lesion and of PT dysfunction were increased, even in normoalbuminuric type 2 DM patients. Serum and urinary IL-6 and IL-17 showed increased levels in type 2 DM patients, across all groups studied. The model provided by univariable regression analysis showed that IL-6 and IL-17 correlated directly with biomarkers of podocyte injury (nephrin, podocalyxin, synaptopodin), of PT dysfunction (KIM-1, NAG, alpha 1-microglobulin), as well as with UACR. Negative correlations have been identified regarding eGFR. In multivariable regression analysis, serum IL-6 correlated directly with synaptopodin, NAG, and negatively with eGFR (p<0.00001, R2=0.805); serum IL-17 correlated directly with synaptopodin, NAG, KIM-1, UACR, and negatively with eGFR (p<0.00001, R2=0.941); urinary IL-6 correlated directly with synaptopodin, NAG, and negatively with eGFR (p<0.00001, R2=0.889); urinary IL-17 correlated directly with synaptopodin, nephrin, NAG, and negatively with eGFR (p<0.00001, R2=0.905). Also, important associations were found between specific interleukins and miRNAs. In univariable regression analysis, IL-6 and IL-17 correlated directly with miRNA-21 and miRNA-124, and negatively with miRNA-146a and miRNA-192. The models provided by multivariable regression analysis showed that urinary IL-6 correlated directly with urinary miRNA-21, and negatively with urinary miRNA-192 (p<0.00001, R2=0.886). Urinary IL-17 displayed direct correlations with urinary miRNA-21, and negative correlations with urinary miRNA-192 (p<0.00001, R2=0.860). Serum IL-6 correlated directly with serum miRNA-21, miRNA-124, and indirectly with serum miRNA-146a, miRNA-192 (p<0.00001, R2=0.862). Serum IL-17 showed direct correlations with serum miRNA-21, miRNA-124, and negative correlations with serum miRNA-192 (p<0.00001, R2=0.745). Conclusion In the early stages of DKD, there is an association of pro-inflammatory cytokines with specific miRNAs, and with biomarkers of podocyte injury and of PT dysfunction. IL-6 and IL-17, as well as dysregulated miRNA-21, miRNA-124, miRNA-146a, and miRNA-192 display a particular molecular pattern, in relation to complex mechanisms that can initiate and maintain the chronic inflammatory response in DKD. Routine detection of these interleukins may provide biomarkers to refine the diagnosis of early renal involvement in the course of type 2 DM, independently of albuminuria and level of renal function.

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