scholarly journals MicroRNA-146a Decreases High Glucose/Thrombin-Induced Endothelial Inflammation by Inhibiting NAPDH Oxidase 4 Expression

2014 ◽  
Vol 2014 ◽  
pp. 1-12 ◽  
Author(s):  
Huang-Joe Wang ◽  
Yuan-Li Huang ◽  
Ya-Yun Shih ◽  
Hsing-Yu Wu ◽  
Ching-Tien Peng ◽  
...  
Keyword(s):  
High Glucose ◽  
Mrna Level ◽  
Regulatory Region ◽  
Fold Increase ◽  
Luciferase Reporter ◽  
Ros Generation ◽  
Aortic Endothelial Cells ◽  
Napdh Oxidase ◽  
Endothelial Inflammation ◽  
Inflammatory Phenotypes

Diabetes is associated with hyperglycemia and increased thrombin production. However, it is unknown whether a combination of high glucose and thrombin can modulate the expression of NAPDH oxidase (Nox) subtypes in human aortic endothelial cells (HAECs). Moreover, we investigated the role of a diabetes-associated microRNA (miR-146a) in a diabetic atherothrombosis model. We showed that high glucose (HG) exerted a synergistic effect with thrombin to induce a 10.69-fold increase in Nox4 mRNA level in HAECs. Increased Nox4 mRNA expression was associated with increased Nox4 protein expression and ROS production. Inflammatory cytokine kit identified that the treatment increased IL-8 and IL-6 levels. Moreover, HG/thrombin treatment caused an 11.43-fold increase of THP-1 adhesion to HAECs.In silicoanalysis identified the homology between miR-146a and the 3′-untranslated region of the Nox4 mRNA, and a luciferase reporter assay confirmed that the miR-146a mimic bound to this Nox4 regulatory region. Additionally, miR-146a expression was decreased to 58% of that in the control, indicating impaired feedback restraint of HG/thrombin-induced endothelial inflammation. In contrast, miR-146a mimic transfection attenuated HG/thrombin-induced upregulation of Nox4 expression, ROS generation, and inflammatory phenotypes. In conclusion, miR-146a is involved in the regulation of endothelial inflammation via modulation of Nox4 expression in a diabetic atherothrombosis model.

High Glucose/Thrombin-Induced Endothelial Inflammation Via Microrna-146a and Nox4 Regulation

Blood ◽  
2014 ◽  
Vol 124 (21) ◽  
pp. 5952-5952
Author(s):  
Ching-Tien Peng ◽  
Wan Yu Lo ◽  
Huang Joe Wang
Keyword(s):  
High Glucose ◽  
Conflicts Of Interest ◽  
Mrna Level ◽  
In Silico Analysis ◽  
Fold Increase ◽  
Ros Generation ◽  
Aortic Endothelial Cells ◽  
Protein Levels ◽  
Endothelial Inflammation

Abstract Diabetes is associated with hyperglycemia and increased thrombin generation. It is unknown whether high glucose (HG)/thrombin can modulate the expression of NAPDH oxidase (Nox) subtypes in human aortic endothelial cells (HAECs). Besides, we investigate whether miR-146a is involved in endothelial cell inflammation. We observed that HG (25 mmol/l) exerted a synergistic effect with thrombin (2 U/ml) for induction of Nox4 mRNA level in HAECs. The increased Nox4 mRNA was associated with increased Nox4 protein and ROS production. We also demonstrated that HG/thrombin treatment increased interleukin-8 and interleukin-6 protein levels. Besides, HG/thrombin treatment caused an 11.43-fold increase of THP-1 adhesion to HAECs. In Silico analysis identified homology between miR-146a and the 3’-UTR of the human Nox4 mRNA, suggesting a potential regulation of Nox4 by miR-146a. Furthermore, HG/thrombin treatment decreased miR146a expression to 58% of the control, indicating an impaired feedback restrain of HG/thrombin-induced endothelial inflammation. MiR-146a mimic transfection prevented HG/thrombin-induced upregulation of Nox4 mRNA, Nox4 protein, and ROS generation. In addition, inflammatory phenotypes were attenuated in miR-146a mimic-transfected HAECs. In conclusion, miR-146a is involved in the regulation of endothelial inflammation via modulation of Nox4 in an in-vitro milieu mimicking diabetic atherothrombosis. Disclosures No relevant conflicts of interest to declare.

Abstract 376: Berry Anthocyanins and Their Metabolite Ameliorate High Glucose-Induced Adhesion of Monocytes to Human Aortic Endothelial Cells by Modulating the Cross-Talk Between eNOS and NFκB Signaling

2014 ◽  
Vol 34 (suppl_1) ◽  
Author(s):  
Anandh Babu Pon Velayutham ◽  
Eui Min Kim ◽  
Leena Panneerseelan-Bharath ◽  
Vasanthi Muthuswamy ◽  
Thunder Jalili ◽  
...  
Keyword(s):  
Endothelial Cells ◽  
High Glucose ◽  
Vascular Inflammation ◽  
Ros Generation ◽  
Monocyte Adhesion ◽  
Enos Expression ◽  
Aortic Endothelial Cells ◽  
Berry Anthocyanins ◽  
Berry Fruits ◽  
Human Aortic Endothelial Cells

Introduction: In diabetes, hyperglycemia-induced vascular inflammation, resulting in the adhesion of monocytes to vascular endothelial cells and their subsequent migration into the subendothelial space, plays a major role in the development of atherosclerosis. ROS induce the inflammatory events involved in diabetic vascular disease by suppressing endothelial nitric oxide synthase (eNOS) through activation of Inhibitor κB kinase (IKKβ), an activator of nuclear factor-κB (NFκB). Aim: To determine the effects of cyanidin-3-glucoside (a major anthocyanin abundant in berry fruits; cyn-3-glu), protocatechuic acid (a major metabolite of anthocyanins; PCA), and bilberry anthocyanins (a mixture of 15 anthocyanins present in bilberry; BBA) on endothelial inflammation induced by hyperglycemia. Methods: Human aortic endothelial cells (HAEC) were cultured in normal (5 mM) or high-glucose (25 mM) ± 1 nM - 10 μM cyn-3-glu, PCA or BBA for 72 h. Cell adhesion (assessed via fluorescent probe labeled THP-1, a human monocytic cell line), intracellular ROS (assessed via DCFH-DH), mRNA expression of eNOS, NFκB-p65, and IKKβ (assessed via qPCR), and cell viability (assessed via CellTiter-Blue assay) were quantified in response to the described treatments. Results: Relative to results obtained from HAEC exposed to 5 mM glucose, ROS generation (42±4%), monocyte adhesion (35±2%), NFκB-p65 expression (80±13%), and IKKβ expression (50±11%) were elevated (p<0.05), whereas eNOS expression was suppressed (50±2%; p<0.05), in cells challenged with high-glucose (n=3-4). Cell viability was maintained regardless of the treatment. The effects of high-glucose on ROS generation, monocyte adhesion, and NFκB-p65, IKKβ and eNOS expression were ameliorated by concurrent treatment with cyn-3-glu or PCA (100 nM). Further, BBA treatment improved the effects of high glucose on ROS and monocyte adhesion. Conclusion: Berry anthocyanins and their metabolite, at concentrations achievable in human plasma by consumption of berry fruits, attenuate glucotoxic vascular inflammation in HAEC by ameliorating NFκB mediated suppression of eNOS signaling. Anthocyanin consumption might be a novel ancillary treatment to prevent vascular complications associated with diabetes.

Mesangial cell NADPH oxidase upregulation in high glucose is protein kinase C dependent and required for collagen IV expression

2006 ◽  
Vol 290 (2) ◽  
pp. F345-F356 ◽  
Author(s):  
L. Xia ◽  
H. Wang ◽  
H. J. Goldberg ◽  
S. Munk ◽  
I. G. Fantus ◽  
...  
Keyword(s):  
Nadph Oxidase ◽  
High Glucose ◽  
Mesangial Cell ◽  
Mesangial Cells ◽  
Fold Increase ◽  
Collagen Iv ◽  
Oxidase Inhibitor ◽  
Ros Generation ◽  
Rt Pcr ◽  
Diabetic Glomerulosclerosis

Excess collagen IV expression by mesangial cells contributes to diabetic glomerulosclerosis. We hypothesized that in high glucose reactive oxygen species (ROS) generation by NADPH oxidase is PKC dependent and required for collagen IV expression by mesangial cells. In rat mesangial cells cultured in 5 mM (NG) or 25 mM d-glucose (HG), RT-PCR and Western immunoblotting detected p22phox and p47phox mRNA and protein, respectively. Quantitative real-time RT-PCR analyzed collagen IV mRNA. With the use of confocal microscopy, ROS were detected with dichlorofluorescein and intracellular collagen IV by immunofluorescence. In HG, ROS were generated within 1 h, sustained up to 48 h, and prevented by a NADPH oxidase inhibitor, diphenylenechloride iodonium (DPI), or a conventional PKC isozyme inhibitor, Gö6976. In NG, phorbol myristate acetate stimulated ROS generation that was inhibited with DPI. In HG, expression of p22phox and p47phox was increased within 3 to 6 h and inhibited by Gö6976. In HG, Gö6976 or transfection with antisense against p22phox reversed the 1.8-fold increase in collagen IV mRNA. In HG, the antioxidants Tempol or Tiron, or transfection with antisense against p22phox or p47phox, prevented ROS generation and the 2.3-fold increase in collagen IV protein. Increased mitochondrial redox potential in HG was unaffected by transfection with antisense against p22phox. We conclude that in HG, mesangial cell ROS generation by upregulated NADPH oxidase is dependent on conventional PKC isozymes and also required for collagen IV expression.

A luciferase-engineered cell line for study of cAMP regulation in endothelial cells

1998 ◽  
Vol 275 (1) ◽  
pp. C75-C81 ◽  
Author(s):  
J. Xavier-Neto ◽  
A. C. Pereira ◽  
A. H. Motoyama ◽  
J. E. Krieger
Keyword(s):  
Endothelial Cells ◽  
Endothelial Cell ◽  
Cell Line ◽  
Fold Increase ◽  
Positive Control ◽  
Luciferase Reporter ◽  
Luciferase Expression ◽  
Luciferase Reporter Gene ◽  
Aortic Endothelial Cells ◽  
Endothelial Cell Line

cAREL is a cAMP-responsive endothelial cell line carrying a luciferase reporter gene introduced by stable transfection of a luciferase enhancer trap into rabbit aortic endothelial cells. Luciferase gene expression in cAREL was stimulated 233-fold by 8-BrcAMP. Treatment with the β-adrenoceptor agonist isoproterenol induced a 7.0-fold increase in luciferase expression, which was partially blocked by either β1- or β2-adrenoceptor antagonists and totally blocked by propranolol and by a combination of β1- plus β2-adrenoceptor antagonists. Receptor stimulation was mimicked by cholera toxin, forskolin, 8-BrcAMP, and isobutylmethylxanthine but not by 8BrcGMP, dexamethasone, or phorbol 12-myristate 13-acetate. Stimulation by isoproterenol was completely blocked by H-89, a protein kinase A inhibitor. cAREL was also stimulated by A-23187, and this effect was abrogated by EGTA and H-89. cAREL is the first cAMP-sensitive endothelial cell line described, and it can be useful as a positive control, as a model for cAMP regulation, as a background to genetic introduction of receptors, as an indicator of intracellular pathway activation, and as a tool to investigate cAMP effects on other signaling pathways.

Long noncoding RNA OIP5-AS1 overexpression promotes viability and inhibits high glucose-induced oxidative stress of cardiomyocytes by targeting microRNA-34a/SIRT1 axis in diabetic cardiomyopathy

2020 ◽  
Vol 21 ◽  
Author(s):  
Haiyun Sun ◽  
Chong Wang ◽  
Ying Zhou ◽  
Xingbo Cheng
Keyword(s):  
Oxidative Stress ◽  
Protein Expression ◽  
Diabetic Cardiomyopathy ◽  
High Glucose ◽  
Long Noncoding Rna ◽  
Noncoding Rna ◽  
Luciferase Reporter ◽  
H9c2 Cells ◽  
Promoting Effect

Objective: Diabetic cardiomyopathy (DCM) is an important complication of diabetes. This study was attempted to discover the effects of long noncoding RNA OIP5-AS1 (OIP5-AS1) on the viability and oxidative stress of cardiomyocyte in DCM. Methods: The expression of OIP5-AS1 and microRNA-34a (miR-34a) in DCM was detected by qRT-PCR. In vitro, DCM was simulated by high glucose (HG, 30 mM) treatment in H9c2 cells. The viability of HG (30 mM)-treated H9c2 cells was examined by MTT assay. The reactive oxygen species (ROS), superoxide dismutase (SOD) and malondialdehyde (MDA) levels were used to evaluate the oxidative stress of HG (30 mM)-treated H9c2 cells. Dual-luciferase reporter assay was used to confirm the interactions among OIP5-AS1, miR-34a and SIRT1. Western blot was applied to analyze the protein expression of SIRT1. Results: The expression of OIP5-AS1 was down-regulated in DCM, but miR-34a was up-regulated. The functional experiment stated that OIP5-AS1 overexpression increased the viability and SOD level, while decreased the ROS and MDA levels in HG (30 mM)-treated H9c2 cells. The mechanical experiment confirmed that OIP5-AS1 and SIRT1 were both targeted by miR-34a with the complementary binding sites at 3′UTR. MiR-34a overexpression inhibited the protein expression of SIRT1. In the feedback experiments, miR-34a overexpression or SIRT1 inhibition weakened the promoting effect on viability, and mitigated the reduction effect on oxidative stress caused by OIP5-AS1 overexpression in HG (30 mM)-treated H9c2 cells. Conclusions: OIP5-AS1 overexpression enhanced viability and attenuated oxidative stress of cardiomyocyte via regulating miR-34a/SIRT1 axis in DCM, providing a new therapeutic target for DCM.

scholarly journals Orai–vascular endothelial-cadherin signaling complex regulates high-glucose exposure-induced increased permeability of mouse aortic endothelial cells

2021 ◽  
Vol 9 (1) ◽  
pp. e002085
Author(s):  
Yuan Wei ◽  
Suwen Bai ◽  
YanHeng Yao ◽  
Wenxuan Hou ◽  
Junwei Zhu ◽  
...  
Keyword(s):  
Endothelial Cells ◽  
Cell Membrane ◽  
High Glucose ◽  
Expression Level ◽  
Vascular Endothelial ◽  
Aortic Endothelial Cells ◽  
Downstream Signaling ◽  
Signaling Complex ◽  
Aortic Endothelium ◽  
Aortic Endothelial

IntroductionDiabetes-associated endothelial barrier function impairment might be linked to disturbances in Ca2+ homeostasis. To study the role and molecular mechanism of Orais–vascular endothelial (VE)-cadherin signaling complex and its downstream signaling pathway in diabetic endothelial injury using mouse aortic endothelial cells (MAECs).Research design and methodsThe activity of store-operated Ca2+ entry (SOCE) was detected by calcium imaging after 7 days of high-glucose (HG) or normal-glucose (NG) exposure, the expression levels of Orais after HG treatment was detected by western blot analysis. The effect of HG exposure on the expression of phosphorylated (p)-VE-cadherin and VE-cadherin on cell membrane was observed by immunofluorescence assay. HG-induced transendothelial electrical resistance was examined in vitro after MAECs were cultured in HG medium. FD-20 permeability was tested in monolayer aortic endothelial cells through transwell permeability assay. The interactions between Orais and VE-cadherin were detected by co-immunoprecipitation and immunofluorescence technologies. Immunohistochemical experiment was used to detect the expression changes of Orais, VE-cadherin and p-VE-cadherin in aortic endothelium of mice with diabetes.Results(1) The expression levels of Orais and activity of SOCE were significantly increased in MAECs cultured in HG for 7 days. (2) In MAECs cultured in HG for 7 days, the ratio of p-VE-cadherin to VE-cadherin expressed on the cell membrane and the FD-20 permeability in monolayer endothelial cells increased, indicating that intercellular permeability increased. (3) Orais and VE-cadherin can interact and enhance the interaction ratio through HG stimulation. (4) In MAECs cultured with HG, the SOCE activator ATP enhanced the expression level of p-VE-cadherin, and the SOCE inhibitor BTP2 decreased the expression level of p-VE-cadherin. (5) Significantly increased expression of p-VE-cadherin and Orais in the aortic endothelium of mice with diabetes.ConclusionHG exposure stimulated increased expression of Orais in endothelial cells, and increased VE-cadherin phosphorylation through Orais–VE-cadherin complex and a series of downstream signaling pathways, resulting in disruption of endothelial cell junctions and initiation of atherosclerosis.

scholarly journals Circ-ACTR2 aggravates the high glucose-induced cell dysfunction of human renal mesangial cells through mediating the miR-205-5p/HMGA2 axis in diabetic nephropathy

2021 ◽  
Vol 13 (1) ◽  
Author(s):  
Jie Yun ◽  
Jinyu Ren ◽  
Yufei Liu ◽  
Lijuan Dai ◽  
Liqun Song ◽  
...  
Keyword(s):  
Oxidative Stress ◽  
Diabetic Nephropathy ◽  
High Glucose ◽  
Cell Injury ◽  
Mesangial Cells ◽  
Protein Detection ◽  
Cell Counting ◽  
Luciferase Reporter ◽  
Enzyme Linked Immunosorbent Assay ◽  
Cell Dysfunction

Abstract Background Circular RNAs (circRNAs) have been considered as pivotal biomarkers in Diabetic nephropathy (DN). CircRNA ARP2 actin-related protein 2 homolog (circ-ACTR2) could promote the HG-induced cell injury in DN. However, how circ-ACTR2 acts in DN is still unclear. This study aimed to explore the molecular mechanism of circ-ACTR2 in DN progression, intending to provide support for the diagnostic and therapeutic potentials of circ-ACTR2 in DN. Methods RNA expression analysis was conducted by the quantitative reverse transcription-polymerase chain reaction (qRT-PCR). Cell growth was measured via Cell Counting Kit-8 and EdU assays. Inflammatory response was assessed by Enzyme-linked immunosorbent assay. The protein detection was performed via western blot. Oxidative stress was evaluated by the commercial kits. The molecular interaction was affirmed through dual-luciferase reporter and RNA immunoprecipitation assays. Results Circ-ACTR2 level was upregulated in DN samples and high glucose (HG)-treated human renal mesangial cells (HRMCs). Silencing the circ-ACTR2 expression partly abolished the HG-induced cell proliferation, inflammation and extracellular matrix accumulation and oxidative stress in HRMCs. Circ-ACTR2 was confirmed as a sponge for miR-205-5p. Circ-ACTR2 regulated the effects of HG on HRMCs by targeting miR-205-5p. MiR-205-5p directly targeted high-mobility group AT-hook 2 (HMGA2), and HMGA2 downregulation also protected against cell injury in HG-treated HRMCs. HG-mediated cell dysfunction was repressed by miR-205-5p/HMGA2 axis. Moreover, circ-ACTR2 increased the expression of HMGA2 through the sponge effect on miR-205-5p in HG-treated HRMCs. Conclusion All data have manifested that circ-ACTR2 contributed to the HG-induced DN progression in HRMCs by the mediation of miR-205-5p/HMGA2 axis.

scholarly journals Glucose-Responsive Gene Delivery at Physiological pH through Tertiary-Amine Stabilized Boronate-PVA Particles Synthesized by One-Pot Reaction

Pharmaceutics ◽  
2021 ◽  
Vol 13 (1) ◽  
pp. 62
Author(s):  
Mangesh Morey ◽  
Akshay Srivastava ◽  
Abhay Pandit
Keyword(s):  
Gene Delivery ◽  
Fold Increase ◽  
Nonviral Gene Delivery ◽  
Luciferase Reporter ◽  
Hydrodynamic Diameter ◽  
Luciferase Reporter Gene ◽  
One Pot ◽  
Gaussia Luciferase ◽  
Nih3t3 Cells ◽  
The Stability

We report a physiologically stable and cytocompatible glucose-responsive nonviral gene delivery system made up of boronate functionalized polymeric material. Herein, we utilize boronate cis-diol interactions to develop a glucose-responsive submicron particle (SMP) system. The stability of the boronate interaction at a physiological pH was achieved by copolymerization of dimethyl aminoethyl methacrylate (DMAEMA) with acrylamidophenylboronic acid (AAPBA) and the formation of a complex with polyvinylalcohol (PVA) which is governed by cis-diol interactions. The shift in hydrodynamic diameter of SMPs was observed and correlated with increasing glucose concentrations at a physiological pH. Optimal transfection was observed for a 5 µg dose of the gaussia luciferase reporter gene in NIH3T3 cells without any adverse effect on cellular viability. The destabilization of the AAPBA–PVA complex by interacting with glucose allowed the release of encapsulated bovine serum albumin (BSA) in a glucose-responsive manner. In total, 95% of BSA was released from SMPs at a 50 mM glucose concentration after 72 h. A two-fold increase in transfection was observed in 50 mM glucose compared to that of 10 mM glucose.

scholarly journals OmpR and LeuO Positively Regulate the Salmonella enterica Serovar Typhi ompS2 Porin Gene

2004 ◽  
Vol 186 (10) ◽  
pp. 2909-2920 ◽  
Author(s):  
Marcos Fernández-Mora ◽  
José Luis Puente ◽  
Edmundo Calva
Keyword(s):  
Salmonella Enterica ◽  
Type Strain ◽  
Wild Type Strain ◽  
Phosphorylation Site ◽  
Regulatory Region ◽  
Random Mutagenesis ◽  
Fold Increase ◽  
Upstream Regulatory Region ◽  
Wild Type ◽  
Transposon Insertion

ABSTRACT The Salmonella enterica serovar Typhi ompS2 gene codes for a 362-amino-acid outer membrane protein that contains motifs common to the porin superfamily. It is expressed at very low levels compared to the major OmpC and OmpF porins, as observed for S. enterica serovar Typhi OmpS1, Escherichia coli OmpN, and Klebsiella pneumoniae OmpK37 quiescent porins. A region of 316 bp, between nucleotides −413 and −97 upstream of the transcriptional start point, is involved in negative regulation, as its removal resulted in a 10-fold increase in ompS2 expression in an S. enterica serovar Typhi wild-type strain. This enhancement in expression was not observed in isogenic mutant strains, which had specific deletions of the regulatory ompB (ompR envZ) operon. Furthermore, ompS2 expression was substantially reduced in the presence of the OmpR D55A mutant, altered in the major phosphorylation site. Upon random mutagenesis, a mutant where the transposon had inserted into the upstream regulatory region of the gene coding for the LeuO regulator, showed an increased level of ompS2 expression. Augmented expression of ompS2 was also obtained upon addition of cloned leuO to the wild-type strain, but not in an ompR isogenic derivative, consistent with the notion that the transposon insertion had increased the cellular levels of LeuO and with the observed dependence on OmpR. Moreover, LeuO and OmpR bound in close proximity, but independently, to the 5′ upstream regulatory region. Thus, the OmpR and LeuO regulators positively regulate ompS2.

Abstract P415: ACE N-domain Regulates High-glucose Mediated Interleukin-1 beta Production by Renal Epithelial Cells Independently From Angiotensin II Generation

Hypertension ◽  
2017 ◽  
Vol 70 (suppl_1) ◽  
Author(s):  
Jorge F Giani ◽  
Ellen A Bernstein ◽  
Masahiro Eriguchi ◽  
Romer A Gonzalez-Villalobos ◽  
Kenneth E Bernstein
Keyword(s):  
Diabetic Nephropathy ◽  
Angiotensin Ii ◽  
Epithelial Cells ◽  
High Glucose ◽  
Interleukin 1 ◽  
Kidney Injury ◽  
Fold Increase ◽  
Renal Epithelial Cells ◽  
Proximal Tubular ◽  
Sense And Respond

Research studies demonstrated that interleukin (IL)-1β contributes to the development of diabetic nephropathy and hypertension. However, the origin and regulation of IL-1β synthesis during diabetic kidney injury are still unknown. Here, we hypothesize that renal epithelial cells produce IL-1β in response to a high glucose stress and that angiotensin converting enzyme (ACE) plays a key role in this process. To study this, we isolated proximal tubular (PT) epithelial cells from wild-type (WT) and mice lacking either the ACE N-domain (NKO) or the C-domain (CKO) catalytic activity. These cells were exposed to normal (5 mM) or high (30 mM) glucose for 24 hours. IL-1β produced by PT cells were assessed by ELISA and RT-PCR. High glucose induced WT PT cells to release significant amounts of IL-1β (from 5±1 to 70±6 pg/ml, p<0.001; n=6). When WT PT cells were exposed to a high glucose media in the presence of an ACE inhibitor (lisinopril, 10 mM), IL-1β levels were significantly reduced (from 70±6 to 38±6 pg/ml, p<0.01). In contrast, AT1 receptor blockade by losartan did not change the amount of IL-1β produced by WT PT cells. To determine which ACE domain is associated with IL-1β production, NKO and CKO PT cells were exposed to high glucose. Strikingly, NKO PT cells released lower amounts of IL-1β when exposed to high glucose compared to WT (NKO: 15±7 vs. WT: 79±9 pg/ml, p<0.01, n=4). No differences were observed between WT and CKO PT cells. Since the ACE N-domain degrades the anti-inflammatory tetrapeptide N-acetyl-Ser-Asp-Lys-Pro (AcSDKP), we tested whether the lower IL-1β production in NKO PT cells was due to an accumulation of AcSDKP. For this, we pre-treated NKO PT cells with a prolyl endopeptidase inhibitor (S17092, 50μM) to prevent the production of AcSDKP. Notably, this treatment increased the IL-1β response to high glucose in NKO PT cells (2.1±0.3-fold increase, p<0.01, n=4). Our data indicate that: 1) PT cells can sense and respond to high glucose by secreting IL-1β and 2) the absence of the ACE N-domain blunts the production of IL-1β through a mechanism that involves AcSDKP accumulation. In conclusion, ACE might contribute to the inflammatory response that underlays diabetic nephropathy independently from angiotensin II generation.

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