Mouse Aortic Endothelial Cells Research Articles

Endothelial cell Ass1 inhibits arteriosclerotic calcification in diabetes mellitus

Endothelial cell (EC) dysfunction is an important pathological feature of early calcification in diabetic plaques. Argininosuccinic synthase 1 (Ass1) is important in protecting EC activity. Therefore, this study aimed to explore the effect of endothelial Ass1 on calcification in diabetic plaques and its potential regulatory mechanism. In this study, serum Ass1 levels were measured in 84 patients, and the study showed that the serum Ass1 level in patients with diabetes was significantly decreased compared with the non-diabetic group, and the serum Ass1 level in patients with coronary artery calcification was significantly decreased compared with the non-coronary artery calcification group. The ApoE-/- mouse diabetic plaque calcification model and the mouse aortic endothelial cell (MAEC) calcification model were constructed, and the influence of endothelial cell Ass1 on diabetic plaque calcification was further investigated by adeno-associated virus and plasmid intervention. Molecular biology studies have shown that endothelial Ass1 overexpression can reduce plaque calcification and inhibit MAEC osteogenic differentiation in diabetic mice, and Ass1 has protective effects on EC and blood vessels in mice. 4D-label-free proteomic sequencing, bioinformatics analysis, and IP experiments were performed on ApoE-/- mouse aorta after adeno-associated virus intervention. It was found that the differential protein Ptk2b was closely related to vascular calcification (VC) and interacted with the target protein Ass1. The above studies indicate that endothelial Ass1 affects calcification formation in diabetic plaques, and the mechanism may be related to Ptk2b. Ass1 may be a new target for the treatment of diabetic VC.

Abstract 4113617: Single-cell Analysis Reveals Endothelial Cell CD45 Deficiency Prevents Endothelial-to-Mesenchymal Transition (EndMT) in Atherosclerosis

Introduction: Protein-tyrosine-phosphatase CD45 is exclusively expressed in all nucleated cells of the hematopoietic system but is rarely expressed in endothelial cells (ECs). However, a recent study indicated that activation of the endogenous CD45 promoter in human endothelial colony forming cells induced expression of EndMT marker genes. Also, the CD45 phosphatase inhibitor blocked EndMT activities in TGFβ1-treated ovine mitral valve endothelial cells. EndMT contributes to atherosclerotic pathobiology and is associated with more complex plaques. We identified CD45-positive ECs undergoing EndMT in atherosclerotic ApoE-deficient (ApoE -/- ) mice. Here, we aim to investigate whether endothelial CD45-specific deletion can prevent EndMT in a mouse model of atherosclerosis. Methods and Results: We generated a tamoxifen-inducible EC-specific CD45-deficient mouse strain (EC-iCD45KO) on an ApoE -/- background (C57BL/6) and fed these mice a Western diet for 16 weeks. We isolated and enriched mouse aortic endothelial cells with CD31 beads to perform single-cell RNA-seq. Cells populated 15 major clusters after integrating the single-cell transcriptomic profiles. In the EC-iCD45KO group, the population of endothelial, resident macrophage, and mesenchymal-endothelial transition cells increased while vascular smooth muscle, EndMT, and fibroblast cells decreased. In EndMT cells, EC markers (Cdh5, Cldn5, Pecam1) increased, but SMC markers (Acta2) and EndMT markers (Col1a2 and Col3a1）decreased. In addition, we characterized EndMT cells into two sub-clusters: 1 and 2. EC-specific CD45 deletions reduced the cell numbers in the EndMT2 sub-cluster in atherosclerotic mice but had less impact on the EndMT1 sub-cluster. FGFR pathways were potentiated while TGFβ1 and Tgfbr2 decreased in EndMT1 sub-cluster， and the genes controlling endothelial cell development were upregulated but the genes controlling actin cytoskeleton organization were downregulated in both EndMT1 and 2 sub-clusters. Conclusion: Our single-cell analysis indicates that the loss of endothelial CD45 protects against EndMT-driven atherosclerosis, inhibiting TGFβ and EndoMT marker expression while stimulating FGFR pathways. Consistently, EC-iCD45KO/ApoE -/- mice showed reduced plaque macrophages, expression of cell adhesion molecules, foam cell formation, and lesion development when compared to ApoE -/- controls. Thus, targeting endothelial CD45 may be a novel therapeutic strategy for EndMT and atherosclerosis.

Novel Role of Endothelial CD45 in Regulating Endothelial-to-Mesenchymal Transition in Atherosclerosis.

Protein-tyrosine-phosphatase CD45 is exclusively expressed in all nucleated cells of the hematopoietic system but is rarely expressed in endothelial cells. Interestingly, our recent study indicated that activation of the endogenous CD45 promoter in human endothelial colony forming cells (ECFCs) induced expression of multiple EndoMT marker genes. However, the detailed molecular mechanisms underlying CD45 that drive EndoMT and the therapeutic potential of manipulation of CD45 expression in atherosclerosis are entirely unknown. We generated a tamoxifen-inducible EC-specific CD45 deficient mouse strain (EC-iCD45KO) in an ApoE-deficient (ApoE-/-) background and fed with a Western diet (C57BL/6) for atherosclerosis and molecular analyses. We isolated and enriched mouse aortic endothelial cells with CD31 beads to perform single-cell RNA sequencing. Biomedical, cellular, and molecular approaches were utilized to investigate the role of endothelial CD45-specific deletion in the prevention of EndoMT in ApoE-/- model of atherosclerosis. Single-cell RNA sequencing revealed that loss of endothelial CD45 inhibits EndoMT marker expression and transforming growth factor-β signaling in atherosclerotic mice. which is associated with the reductions of lesions in the ApoE-/- mouse model. Mechanistically, the loss of endothelial cell CD45 results in increased KLF2 expression, which inhibits transforming growth factor-β signaling and EndoMT. Consistently, endothelial CD45 deficient mice showed reduced lesion development, plaque macrophages, and expression of cell adhesion molecules when compared to ApoE-/- controls. These findings demonstrate that the loss of endothelial CD45 protects against EndoMT-driven atherosclerosis, promoting KLF2 expression while inhibiting TGFβ signaling and EndoMT markers. Thus, targeting endothelial CD45 may be a novel therapeutic strategy for EndoMT and atherosclerosis.

SGK1 contributes to ferroptosis in coronary heart disease through the NEDD4L/NF-κB pathway

The prevalence of coronary heart disease (CHD) has increased significantly with the aging population worldwide. It is unclear whether ferroptosis occurs during CHD. Hence, we aimed to investigate the potential mechanisms associated with ferroptosis in CHD. Bioinformatics was used to characterize differentially expressed genes (DEGs) in CHD-related datasets (GSE21610 and GSE66360). There were 76 and 689 DEGs in the GSE21610 and GSE66360, respectively, and they predominantly associated with immune and inflammatory responses. DDX3Y, EIF1AY, KDM5D, RPS4Y1, SGK1, USP9Y, and NSG1 were intersecting DEGs of GSE21610 and GSE66360. Their expression pattern in circulating endothelial cells (ECs) derived from healthy individuals and CHD patients are consistent with the results of bioinformatics analysis, especially SGK1. In vitro, SGK1 knockdown alleviated the Erastin-induced downregulation of SLC7A11, GPX4, GSH, and GSSG, as well as the upregulation of lipid peroxidation, Fe accumulation, and mitochondrial damage in mouse aortic ECs (MAECs). Notably, SGK1 may interact with NEDD4L according to the String database. Moreover, SGK1 promoted NEDD4L and p-P65 expression in MAECs. Interestingly, the effect of SGK1 knockdown on ferroptosis in MAECs was rescued by overexpression of NEDD4L or PMA (NF-κB pathway activator). In vivo, SGK1 knockdown facilitated the recovery of body weight, blood lipids, and aortic tissue structure in CHD animal models. Furthermore, SGK1 knockdown alleviated Fe accumulation in the aorta and inactivated the NEDD4L-NF-κB pathway. In conclusion, SGK1 contributes to EC ferroptosis by regulating the NEDD4L-NF-κB pathway. SGK1 could be recognized as a therapeutic target related to ferroptosis in CHD.

Activity and function of the endothelial sodium channel is regulated by the effector domain of MARCKS like protein 1 in mouse aortic endothelial cells.

The endothelial sodium channel (EnNaC) plays an important role in regulating vessel stiffness. Here, we investigated the regulation of EnNaC in mouse aortic endothelial cells (mAoEC) by the actin cytoskeleton and lipid raft association protein myristoylated alanine-rich C-kinase substrate like protein 1 (MLP1). We hypothesized that mutation of specific amino acid residues within the effector domain of MLP1 or loss of association between MLP1 and the anionic phospholipid phosphate PIP2 would significantly alter membrane association and EnNaC activity in mAoEC. mAoEC transiently transfected with a mutant MLP1 construct (three serine residues in the effector domain replaced with aspartate residues) showed a significant decrease in EnNaC activity compared to cells transfected with wildtype MLP1. Compared to vehicle treatment, mAoEC treated with the PIP2 synthesis blocker wortmannin showed less colocalization of EnNaC and MLP1. In other experiments, Western blot and densitometric analysis showed a significant decrease in MLP1 and caveloin-1 protein expression in mAoEC treated with wortmannin compared to vehicle. Finally, wortmannin treatment decreased sphingomyelin content and increased membrane fluidity in mAoEC. Taken together, our results suggest constitutive phosphorylation of MLP1 attenuates the function of EnNaC in aortic endothelial cells by a mechanism involving a decrease in association with MLP1 and EnNaC at the membrane, while deletion of PIP2 decreases MARCKS expression and overall membrane fluidity.

Abstract 2063: Endothelial Cell Scavenger Receptor Class B, Type I Expression Is Transcriptionally Controlled By HIF-1α

Background: Scavenger Receptor Class B, Type I (SR-BI), encoded by Scarb1, mediates LDL cholesterol transcytosis in endothelial cells (EC) to deliver circulating LDL into the subendothelial space to drive atherogenesis. Research Questions: It is unknown whether EC SR-BI expression is altered in atherosclerosis, and how EC SR-BI expression is regulated. Approach: Single cell RNAseq was performed on coronary arteries from 5 ischemic heart disease patients, in segments both with and without a grossly apparent atheroma. Transcription factor (TF) network analysis was done to reveal possible regulatory relationships between differentially-expressed genes (DEGs). The modulation of EC SR-BI was studied in primary human aortic EC (HAEC) and in vivo in mouse aortic EC. ChIP-seq, ChIP-qPCR and CRISPR-based mutagenesis were used to interrogate TF binding to the human Scarb1 gene. EC SR-BI expression was determined by immunoblotting and qPCR, and EC LDL transcytosis was studied in transwells using DiI-labeled LDL. Results: SR-BI expression was greater in EC in coronary segments with atheroma versus those without atheroma (p=0.003). TF networks for DEGs in atheroma versus non-atheroma EC, and for DEGs in EC with low versus high SR-BI revealed multiple TF with possible regulatory relationships with Scarb1. One TF in common was HIF-1α. In HAEC, an increase in HIF-1α with the HIF prolyl hydroxylase inhibitor dimethyloxalylglycine (DMOG) caused upregulation of SR-BI mRNA and protein, and a parallel increase in LDL transcytosis that was entirely SR-BI-dependent. Expression of a constitutively-active HIF-1α variant also increased SR-BI and LDL transcytosis. ChIP-seq revealed a HIF-1α binding site in Scarb1 intron 1, and HIF-1α binding there increased 4-fold with DMOG. CRISPR deletion of the binding site fully prevented SR-BI upregulation by DMOG without affecting known HIF-1α target genes. In mice, 3d treatment with DMOG increased SR-BI in aortic EC. Conclusions: EC expression of SR-BI is upregulated with increasing atherosclerosis severity in human coronary artery. HIF-1α is upregulated in parallel, and HIF-1α causes the direct transcriptional upregulation of EC SR-BI leading to enhanced EC LDL transport. HIF-1α control of SR-BI in EC may be critical to atherogenesis.

Abstract 1078: A Cross-species Platform And Phosphoproteomics Analysis To Mitigate Vegfri-induced Hypertension And Endothelial Dysfunction

Introduction: Vascular endothelial growth factor receptor inhibitors (VEGFRis) are a class of tyrosine kinase inhibitors (TKIs) used to treat human and canine cancers, but these drugs also cause hypertension (HTN) and endothelial cell (EC) dysfunction. Purpose: We combined phosphoproteomic analysis in ECs with a cross-species in-vitro and in-vivo approach to identify mitigating therapies for VEGFRi-induced EC dysfunction and HTN. Methods and Results: We developed a sorafenib-induced HTN mouse model showing increased blood pressure, mesenteric resistance vessel EC dysfunction (decreased phosphorylation of Ser1177 on endothelial nitric oxide synthase [p-eNOS], increased endothelin-1 [ET-1]), and renal glomerular endotheliosis. Human umbilical vein ECs were treated with VEGFR TKIs, non-VEGFR TKIs, and cardiovascular drugs. Phosphoproteomic mass spectrometry and a marker selection algorithm identified a 14-phosphopeptide signature differentiating VEGFR TKIs from non-VEGFR TKIs. The signature peptide RBM17 pS222 increased with VEGFRi treatment in human, canine, and mouse aortic ECs, correlating with reduced p-eNOS. By screening for cardiovascular drugs that reverse the VEGFRi phosphoproteomic signature, we found alpha-adrenergic antagonists, particularly doxazosin, had the most anti-correlated signatures. Doxazosin prevented VEGFRi-induced EC dysfunction in primary aortic ECs across species. In mice, doxazosin reversed sorafenib-induced EC dysfunction in resistance vessels without affecting blood pressure or renal glomerular endotheliosis. Conversely, lisinopril reduced HTN and glomerular endotheliosis but not EC dysfunction. Preliminary results from our clinical trial in canine cancer patients confirmed that toceranib induced HTN and showed that both doxazosin and lisinopril significantly lowered blood pressure in dogs with cancer and VEGFRi-induced HTN. Conclusion: Our study demonstrates the utility of phosphoproteomics and cross-species analysis in identifying EC-protective effects of doxazosin in VEGFRi-induced HTN. Our mouse data suggest distinct mechanisms for VEGFRi-induced EC dysfunction and HTN, potentially involving renal glomerular damage.

NOS3 prevents MMP-9, and MMP-13 induced extracellular matrix proteolytic degradation through specific microRNA-targeted expression of extracellular matrix metalloproteinase inducer in hypertension-related atherosclerosis.

Endothelial nitric oxide synthase (NOS3) elicits atheroprotection by preventing extracellular matrix (ECM) proteolytic degradation through inhibition of extracellular matrix metalloproteinase inducer (EMMPRIN) and collagenase MMP-13 by still unknown mechanisms. C57BL/6 mice lacking ApoE , NOS3, and/or MMP13 were fed with a high-fat diet for 6 weeks. Entire aortas were extracted and frozen to analyze protein and nucleic acid expression. Atherosclerotic plaques were detected by ultrasound imaging, Oil Red O (ORO) staining, and Western Blot. RNA-seq and RT-qPCR were performed to evaluate EMMPRIN, MMP-9, and EMMPRIN-targeting miRNAs. Mouse aortic endothelial cells (MAEC) were incubated to assess the role of active MMP-13 over MMP-9. One-way ANOVA or Kruskal-Wallis tests were performed to determine statistical differences. Lack of NOS3 in ApoE null mice fed with a high-fat diet increased severe plaque accumulation, vessel wall widening, and high mortality, along with EMMPRIN-induced expression by upregulation of miRNAs 46a-5p and 486-5p. However, knocking out MMP-13 in ApoE/NOS3 -deficient mice was sufficient to prevent mortality (66.6 vs. 26.6%), plaque progression (23.1 vs. 8.8%), and MMP-9 expression, as confirmed in murine aortic endothelial cell (MAEC) cultures, in which MMP-9 was upregulated by incubation with active recombinant MMP-13, suggesting MMP-9 as a new target of MMP-13 in atherosclerosis. We describe a novel mechanism by which the absence of NOS3 may worsen atherosclerosis through EMMPRIN-induced ECM proteolytic degradation by targeting the expression of miRNAs 146a-5p and 485-5p. Focusing on NOS3 regulation of ECM degradation could be a promising approach in the management of atherosclerosis.

T1-weighted MRI of targeting atherosclerotic plaque based on CD40 expression on engulfed USPIO’s cell surface

Atherosclerosis is a chronic inflammatory disease characterized by the accumulation of cholesterol within the arterial wall. Its progression can be monitored via magnetic resonance imaging (MRI). Ultrasmall Superparamagnetic Particles of Iron Oxide (USPIO) (<5 nm) have been employed as T1 contrast agents for MRI applications. In this study, we synthesized USPIO with an average surface carboxylation of approximately 5.28 nm and a zeta potential of −47.8 mV. These particles were phagocytosed by mouse aortic endothelial cells (USPIO-MAECs) and endothelial progenitor cells (USPIO-EPCs), suggesting that they can be utilized as potential contrast agent and delivery vehicle for the early detection of atherosclerosis. However, the mechanism by which this contrast agent is delivered to the plaque remains undetermined. Our results demonstrated that with increasing USPIO concentration during 10–100 μg ml−1, consistent change appeared in signal enhancement on T1-weighted MRI. Similarly, T1-weighted MRI of MAECs and EPCs treated with these concentrations exhibited a regular change in signal enhancement. Prussian blue staining of USPIO revealed substantial absorption into MAECs and EPCs after treatment with 50 μg ml−1 USPIO for 24 h. The iron content in USPIO-EPCs was much higher (5 pg Fe/cell) than in USPIO-MAECs (0.8 pg Fe/cell). In order to substantiate our hypothesis that CD40 protein on the cell surface facilitates migration towards inflammatory cells, we utilized AuNPs-PEI (gold nanoparticles-polyethylenimine) carrying siRNACD40 to knockout CD40 expression in MAECs. It has been documented that gold nanoparticle-oligonucleotide complexes could be employed as intracellular gene regulation agents for the control of protein level in cells. Our results confirmed that macrophages are more likely to bind to MAECs treated with AuNPs-PEI-siRNANC (control) for 72 h than to MAECs treated with AuNPs-PEI-siRNACD40 (reduced CD40 expression), thus confirming CD40 targeting at the cellular level. When USPIO-MAECs and MAECs (control) were delivered to mice (high-fat-fed) via tail vein injection respectively, we observed a higher iron accumulation in plaques on blood vessels in high-fat-fed mice treated with USPIO-MAECs. We also demonstrated that USPIO-EPCs, when delivered to high-fat-fed mice via tail vein injection, could indeed label plaques by generating higher T1-weighted MRI signals 72 h post injection compared to controls (PBS, USPIO and EPCs alone). In conclusion, we synthesized a USPIO suitable for T1-weighted MRI. Our results have confirmed separately at the cellular and tissue and in vivo level, that USPIO-MAECs or USPIO-EPCs are more accessible to atherosclerotic plaques in a mouse model. Furthermore, the high expression of CD40 on the cell surface is a key factor for targeting and USPIO-EPCs may have potential therapeutic effects.

Bioactivity of cerium dioxide nanoparticles as a function of size and surface features.

Nano-dispersed cerium dioxide is promising for use in medicine due to its unique physicochemical properties, including low toxicity, the safety of in vivo usage, active participation in different redox processes occurring in living cells, and its regenerative potential, manifested in the ability of CeO2 to participate repeatedly in redox reactions. In this work, we examined the biological activity of cerium dioxide nanoparticles (CeO2 NPs) synthesized by precipitation in mixed water/alcohol solutions at a constant pH of 9. This synthesis method allowed controlling the size and Ce3+/Ce4+ proportion on the surface of NPs, changing the synthesis conditions and obtaining highly stable suspensions of "naked" CeO2 NPs. Changes in the surface properties upon contact of CeO2 NPs with protein-rich media, e.g., bovine serum albumin and DMEM cell culture medium supplemented with 10% fetal bovine serum, the characteristics of nanoparticle uptake by mouse aortic endothelial cells and the antioxidant activity of the nanoparticles of different sizes were investigated by various state-of-the-art analytical methods.

MiR-509-3p promotes oxidized low-density lipoprotein-induced apoptosis in mouse aortic endothelial cells

To investigate the effect of microRNA-509-3p (miR-509-3p) on the apoptosis of atherosclerotic vascular endothelial cells. Mouse aortic endothelial cells (MAECs) were divided into normal control group, oxidized low-density lipoprotein (ox-LDL) group, miR-509-3p overexpression group, miR-509-3p overexpression control group, miR-509-3p inhibitor + ox-LDL group, and miR-509-3p inhibitor control + ox-LDL group. MAEC were induced with 100 mg/L ox-LDL for 24 hours, and then transfected with miR-509-3p overexpression/inhibitor and corresponding control for 48 hours. The miR-509-3p expression in MAECs exposed to ox-LDL was detected using real-time fluorescence quantitative polymerase chain reaction (RT-qPCR). Flow cytometry was used to detect the level of apoptosis, and cell counting kit (CCK-8) was used to detect the proliferation activity of MAECs. The direct gene targets of miR-509-3p were predicted using bioinformatics analyses and confirmed using a dual luciferase reporter assay. The expression of Bcl-2 mRNA and protein was detected by RT-qPCR and Western blotting, respectively. Compared with the normal control group, miR-509-3p was significantly upregulated in ox-LDL-stimulated MAECs (1.68±0.85 vs. 1.00±0.30, t = 2.398, P < 0.05). After transfection of MAECs with miR-509-3p overexpression, the luciferase activity of the BCL2 3'UTR WT reporter gene was significantly lower than that of miR-509-3p overexpression control group (0.83±0.06 vs. 1.00±0.07, t = 4.531, P = 0.001). The luciferase activity of the BCL2 3'-UTR mutant (MUT) reporter gene was not significantly different from that of miR-509-3p overexpression control group (0.94±0.05 vs. 1.00±0.08, t = 1.414, P = 0.188). Compared with the normal control group and miR-509-3p mimics control group, the cell proliferation activity was decreased [(0.60±0.06)% vs. (1.00±0.09)%, (0.89±0.04)%, both P < 0.01], the percentage of apoptotic cells were increased [(23.46±2.02)% vs. (7.66±1.52)%, (10.40±0.78)%, both P < 0.05], and the mRNA and protein expression of Bcl-2 were significantly downregulated (Bcl-2 mRNA: 0.52±0.13 vs. 1.00±0.36, 1.10±0.19, Bcl-2 protein: 0.42±0.07 vs. 1.00±0.11, 0.93±0.10, both P < 0.01) in miR-509-3p overexpression group. Compared with the ox-LDL group, inhibition of miR-509-3p expression could increase the proliferation activity of MAECs induced by ox-LDL [(0.64±0.35)% vs. (0.34±0.20%)%, P < 0.05], and reduce the apoptosis rate [(13.59±2.22)% vs. (29.84±5.19)%, P < 0.01], and up-regulated the expression of Bcl-2 mRNA and protein in MAECs induced by ox-LDL (Bcl-2 mRNA relative expression: 0.82±0.09 vs. 0.52±0.10, Bcl-2 protein relative expression: 0.83±0.17 vs. 0.40±0.07, both P < 0.05). Bcl-2 was one of the target genes of miR-509-3p. miR-509-3p can reduce the proliferation activity of endothelial cells, reduce the expression of Bcl-2, and promote cell apoptosis, thereby promoting the occurrence and development of atherosclerosis. Inhibition of miR-509-3p expression may be a potential therapeutic target for atherosclerosis.

SIRT1 mediates the inhibitory effect of Dapagliflozin on EndMT by inhibiting the acetylation of endothelium Notch1

BackgroundEndothelial–mesenchymal transition (EndMT) plays a crucial role in promoting myocardial fibrosis and exacerbating cardiac dysfunction. Dapagliflozin (DAPA) is a sodium–glucose-linked transporter 2 (SGLT-2) inhibitor that has been shown to improve cardiac function in non-diabetic patients with heart failure (HF). However, the precise mechanisms by which DAPA exerts its beneficial effects are yet to be fully elucidated.MethodsIsoproterenol (ISO) was used to generate a HF model in mice. For in vitro experiments, we used TGF-β1-stimulated human umbilical vein endothelial cells (HUVECs) and mouse aortic endothelial cells (MAECs).ResultsBoth our in vivo and in vitro results showed that EndMT occurred with decreased SIRT1 (NAD+-dependent deacetylase) protein expression, which could be reversed by DAPA therapy. We found that the protective effect of DAPA was significantly impaired upon SIRT1 inhibition. Mechanistically, we observed that SIRT1 phosphorylation, a required modification for its ubiquitination and degradation, was reduced by DAPA treatment, which induces the nucleus translocation of SIRT1 and promotes its binding to the active intracellular domain of Notch1 (NICD). This interaction led to the deacetylation and degradation of NICD, and the subsequent inactivation of the Notch1 signaling pathway which contributes to ameliorating EndMT.ConclusionsOur study revealed that DAPA can attenuate EndMT induced by ISO in non-diabetic HF mice. This beneficial effect is achieved through SIRT1-mediated deacetylation and degradation of NICD. Our findings provide greater insight into the underlying mechanisms of the therapeutic effects of DAPA in non-diabetic HF.Graphical

Abstract 18579: Endocytic Adaptor Protein DAB2 is a Novel Atheroprotective Regulator in Atherosclerosis

Introduction: Endothelial dysfunction and arterial inflammation are critically important for cardiovascular diseases such as atherosclerosis. Of major importance, they are among the predominant culprits that promote the transition from stable to vulnerable atheromas. Our pilot studies revealed Disabled Homolog 2 (Dab2) deficiency in endothelial cells (EC) results in endothelial dysfunction. However, the molecular mechanisms that direct Dab2 to combat endothelial dysfunction during atherosclerosis are completely unknown. Hypothesis: Dab2 prevents the progress of atherosclerosis by maintaining EC function and reducing inflammatory factors. Methods and Results: We examined the expression of endothelial Dab2 in human atherosclerosis patients and ApoE -/- mice fed a western diet (WD) for 12 weeks by immunoflurecent co-staining of VE-cadherin and Dab2 and observed drastically reduced Dab2 expression in the endothelium and intima of human fatty streaks and mouse atherosclerotic aortae. Genetic deletion of Dab2 in the endothelium of ApoE -/- mice on a WD for 12 weeks significantly increased atherosclerosis as revealed by Oil Red O staining of aortic roots and arches, suggesting that Dab2 could be a atheroprotective flow-responsive gene. Similar results were found in WT and EC-iDab2KO mice injected with AAv8-PCSK9 virus. RNA-seq of primary mouse aortic ECs (MAECs) isolated from WT and EC-Dab2iKO mice revealed Dab2 deficiency upregulated many inflammatory genes. qRT-PCR confirmed TNF-α and IL-6 were significantly upregulated in Dab2KO MAECs. Additionally, we observed an increase in Dab2 binding to NEMO in the absence of endocytic adapter proteins epsins via co-IP with anti-Dab2 in WT and epsin-deficient DKO MAECs. We also found three Klf4 binding sites present in the Dab2 gene promoter/enhancer and that overexpression of Klf4 upregulated Dab2 expression in a dosage-dependent manner. Conclusions: Our findings indicated the essential role of Dab2 in protecting the atherogenic endothelium by reducing macrophage accumulation and increasing plaque stability in the aortic roots, which may provide new anti-atherosclerotic therapeutics.

Dysfunctional APPL1-Mediated Epigenetic Regulation in Diabetic Vascular Injury.

APN (adiponectin) and APPL1 (adaptor protein, phosphotyrosine interacting with PH domain and leucine zipper 1) are potent vasculoprotective molecules, and their deficiency (eg, hypoadiponectinemia) contributes to diabetic vascular complications. However, the molecular mechanisms that govern their vasculoprotective genes as well as their alteration by diabetes remain unknown. Diabetic medium-cultured rat aortic endothelial cells, mouse aortic endothelial cells from high-fat-diet animals, and diabetic human aortic endothelial cells were used for molecular/cellular investigations. The in vivo concept-prove demonstration was conducted using diabetic vascular injury and diabetic hindlimb ischemia models. In vivo animal experiments showed that APN replenishment caused APPL1 nuclear translocation, resulting in an interaction with HDAC (histone deacetylase) 2, which inhibited HDAC2 activity and increased H3Kac27 levels. Based on transcriptionome pathway-specific real-time polymerase chain reaction profiling and bioinformatics analysis, Angpt1 (angiopoietin 1), Ocln (occludin), and Cav1 (caveolin 1) were found to be the top 3 vasculoprotective genes suppressed by diabetes and rescued by APN in an APPL1-dependent manner. APN reverses diabetes-induced inhibition of Cav1 interaction with APPL1. APN-induced Cav1 expression was not affected by Angpt1 or Ocln deficiency, whereas APN-induced APPL1 nuclear translocation or upregulation of Angpt1/Ocln expression was abolished in the absence of Cav1 both in vivo and in vitro, suggesting Cav1 is upstream molecule of Angpt1/Ocln in response to APN administration. Chromatin immunoprecipitation-qPCR (quantitative polymerase chain reaction) demonstrated that APN caused significant enrichment of H3K27ac in Angpt1 and Ocln promoter region, an effect blocked by APPL1/Cav1 knockdown or HDAC2 overexpression. The protective effects of APN on the vascular system were attenuated by overexpression of HDAC2 and abolished by knocking out APPL1 or Cav1. The double knockdown of ANGPT1/OCLN blunted APN vascular protection both in vitro and in vivo. Furthermore, in diabetic human endothelial cells, HDAC2 activity is increased, H3 acetylation is decreased, and ANGPT1/OCLN expression is reduced, suggesting that the findings have important translational implications. Hypoadiponectinemia and dysregulation of APPL1-mediated epigenetic regulation are novel mechanisms leading to diabetes-induced suppression of vasculoprotective gene expression. Diabetes-induced pathological vascular remodeling may be prevented by interventions promoting APPL1 nuclear translocation and inhibiting HDAC2.

Inflammatory Cell-Derived MYDGF Attenuates Endothelial LDL Transcytosis to Protect Against Atherogenesis.

Inflammation contributes to the pathogenesis of atherosclerosis. But little is known about the potential benefits of inflammatory cells to atherosclerosis. The aim of this study was to investigate the function of inflammatory cells/endothelium axis and determine whether and how inflammatory cell-derived MYDGF (myeloid-derived growth factor) inhibited endothelial LDL (low-density lipoprotein) transcytosis. In in vivo experiments, both loss- and gain-of-function strategies were used to evaluate the effect of inflammatory cell-derived MYDGF on LDL transcytosis. We generated monocyte/macrophage-targeted MYDGF-null mice on an Ldlr (LDL receptor)-/- background in the loss-of-function strategy and restored the inflammatory cell-derived MYDGF by bone marrow transplantation and inflammatory cell-specific overexpression of MYDGF mice model in the gain-of-function strategy. In in vitro experiments, coculture experiments between primary mouse aortic endothelial cells and macrophages and mouse aortic endothelial cells supplemented with or without recombinant MYDGF were conducted. Inflammatory cell-derived MYDGF deficiency aggravated endothelial LDL transcytosis, drove LDL uptake by artery wall, and thus exacerbated atherosclerosis in vivo. Inflammatory cell-derived MYDGF restoration by bone marrow transplantation and inflammatory cell MYDGF overexpression alleviated LDL transport across the endothelium, prevented LDL accumulation in the subendothelial space, and subsequently ameliorated atherosclerosis in vivo. Furthermore, in the in vitro study, macrophages isolated from MYDGF+/+ mice and recombinant MYDGF attenuated LDL transcytosis and uptake in mouse aortic endothelial cells. Mechanistically, MYDGF inhibited MAP4K4 (mitogen-activated protein kinase kinase kinase kinase isoform 4) phosphorylation, enhanced activation of Akt (protein kinase B)-1, and diminished the FoxO (forkhead box O) 3a signaling cascade to exert protective effects of MYDGF on LDL transcytosis and atherosclerosis. The findings support a role for inflammatory cell-derived MYDGF served as a cross talk factor between inflammatory cells and endothelial cells that inhibits LDL transcytosis across endothelium. MYDGF may become a novel therapeutic drug for atherosclerosis, and the beneficial effects of inflammatory cell in atherosclerosis deserve further attention.

Abstract 054: Role Of The Immunoproteasome In Hypertension-associated Immune Activation

Background: Inflammation is essential for the development of hypertension (HTN), however the mechanisms underlying this process remain unclear. The immunoproteasome processes intracellular peptides for display within class I major histocompatibility complexes (MHC-I). LMP7 is the chymotrypsin subunit of the immunoproteasome. Isolevuglandins (isoLGs) are reactive oxygen species (ROS) that drive immune activation and contribute to the development of HTN. Methods: IsoLG adduct-MHC-I interaction was measured by fluorescence resonance energy transfer. Mice with LoxP sites flanking exons 1 and 2 of Psmb8 , the gene encoding the immunoproteasome subunit LMP7, were generated and crossed to mice expressing dendritic cell (DC) and endothelial cell (EC) specific cre-recombinase. Mice were treated with angiotensin II as a model of HTN and blood pressure was measured by radiotelemetry. Tissue inflammation was measured by flow cytometry. In vitro , DCs, ECs, and B8 fibroblasts were used to study IsoLG adduct processing. Mouse aortic ECs (MAECs) were studied in models of isoLG-mediated T cell proliferation, gene expression, and antigen presentation. Results: Overexpression of immunoproteasome subunits augments isoLG-adduct MHC-I presentation. Oxidative stress induces IsoLG adduct MHC-I presentation by ECs and DCs. EC-specific IsoLG adduct MHC-I presentation contributes to hypertensive T-cell proliferation. Conditional deletion of LMP7 in DCs attenuated both tissue inflammation and HTN (142.3 ± 13.3 mmHg in Psmb8 fl/fl mice compared to 127.1 ± 9.5 mmHg in Psmb8 fl/fl /CD11c-Cre mice, N = 5-6, p=0.0363). Similarly, EC-specific LMP7 loss-of function attenuated inflammation and HTN (142.9 ± 3.4 mm Hg in Psmb8 fl/fl mice compared to 119.2 ± 2.6 mm Hg in Psmb8 fl/fl /vecadherin-Cre mice, N = 5, p= 0.0094). IsoLGs increase LMP7 expression and STING activation in MAECs. Conclusions: These studies define a critical role of the immunoproteasome in the regulation of immune cell activation and tissue infiltration in HTN. Moreover, they define a mechanism of isoLG adduct MHC-I presentation as a driver of this process. Finally, these studies define a critical role of antigen presentation in T cell activation, proliferation, and migration in HTN.

Intranasal Delivery of Endothelial Cell-Derived Extracellular Vesicles with Supramolecular Gel Attenuates Myocardial Ischemia-Reperfusion Injury.

Myocardial ischemia-reperfusion injury after myocardial infarction has always been a difficult problem in clinical practice. Endothelial cells and their secreted extracellular vesicles are closely related to inflammation, thrombosis formation, and other processes after injury. Meanwhile, low-molecular-weight gelators have shown great potential for nasal administration. This study aims to explore the therapeutic effects and significance of endothelial cell-derived extracellular vesicles combined with a hydrogel for nasal administration on myocardial ischemia-reperfusion injury. We chose a gel system composed of a derivative of glutamine amide and benzaldehyde as the extracellular vesicle delivery vehicle. This hydrogel was combined with extracellular vesicles extracted from mouse aortic endothelial cells and administered multiple times intranasally in a mouse model of ischemia-reperfusion injury to the heart. The delivery efficiency of the extracellular vesicle-hydrogel combination was evaluated by flow cytometry and immunofluorescence. Echocardiography, TTC Evan's Blue and Masson's staining were used to assess mouse cardiac function, infarct area, and cardiac fibrosis level. Flow cytometry, ELISA, and immunofluorescence staining were used to investigate changes in mouse inflammatory cells, cytokines, and vascular neogenesis. The vesicles combined with the hydrogel have good absorption in the nasal cavity. The hydrogel combined with vesicles reduces the levels of pro-inflammatory Ly6C (high) monocytes/macrophages and neutrophils. It can also reduce the formation of microcirculation thrombi in the infarcted area, improve endothelial barrier function, and increase microvascular density in the injured area. As a result, the heart function of mice is improved and the infarct area is reduced. We first demonstrated that the combination of extracellular vesicles and hydrogel has a better absorption efficiency in the nasal cavity, which can improve myocardial ischemia-reperfusion injury by inhibiting inflammatory reactions and protecting endothelial function. Nasal administration of vesicles combined with hydrogel is a potential therapeutic direction.

Efficient delivery of mesenchymal stem/stromal cells to injured liver by surface PEGylation

BackgroundMesenchymal stem/stromal cells (MSCs) have been used in clinical trials for various diseases. These have certain notable functions such as homing to inflammation sites, tissue repair, and immune regulation. In many pre-clinical studies, MSCs administered into peripheral veins demonstrated effective therapeutic outcomes. However, most of the intravenously administered MSCs were entrapped in the lung, and homing to target sites was less than 1%. This occurred mainly because of the adhesion of MSCs to vascular endothelial cells in the lung. To prevent this adhesion, we modified the surface of MSCs with polyethylene glycol (PEG; a biocompatible polymer) using the avidin–biotin complex (ABC) method.MethodsThe surface of MSCs was modified with PEG using the ABC method. Then, the cell adhesion to mouse aortic endothelial cells and the tissue distribution of PEG-modified MSCs were evaluated. Moreover, the homing to the injured liver and therapeutic effect of PEG-modified MSCs were evaluated using carbon tetrachloride-induced acute liver failure model mice.ResultsThe PEG modification significantly suppressed the adhesion of MSCs to cultured mouse aortic endothelial cells as well as the entrapment of MSCs in the lungs after intravenous injection in mice. PEG-modified MSCs efficiently homed to the injured liver of carbon tetrachloride-induced acute liver failure model mice. More importantly, the cells significantly suppressed serum transaminase levels and leukocyte infiltration into the injured liver.ConclusionThese results indicate that PEG modification to the surface of MSCs can suppress the lung entrapment of intravenously administered MSCs and improve their homing to the injured liver.Graphical

Resveratrol Improves Endothelial Function by A PREP1-Mediated Pathway in Mouse Aortic Endothelial Cells.

PREP1 is a homeodomain transcription factor that impairs metabolism and is involved in age-related aortic thickening. In this study, we evaluated the role of PREP1 on endothelial function. Mouse Aortic Endothelial Cells (MAECs) transiently transfected with a Prep1 cDNA showed a 1.5- and 1.6-fold increase in eNOSThr495 and PKCα phosphorylation, respectively. Proinflammatory cytokines Tnf-α and Il-6 increased by 3.5 and 2.3-fold, respectively, in the presence of Prep1, while the antioxidant genes Sod2 and Atf4 were significantly reduced. Bisindolylmaleimide reverted the effects induced by PREP1, suggesting PKCα to be a mediator of PREP1 action. Interestingly, resveratrol, a phenolic micronutrient compound, reduced the PREP1 levels, eNOSThr495, PKCα phosphorylation, and proinflammatory cytokines and increased Sod2 and Atf4 mRNA levels. The experiments performed on the aorta of 18-month-old Prep1 hypomorphic heterozygous mice (Prep1i/+) expressing low levels of this protein showed a 54 and 60% decrease in PKCα and eNOSThr495 phosphorylation and a 45% reduction in Tnf-α levels, with no change in Il-6, compared to same-age WT mice. However, a significant decrease in Sod2 and Atf4 was observed in Prep1i/+ old mice, indicating the lack of age-induced antioxidant response. These results suggest that Prep1 deficiency partially improved the endothelial function in aged mice and suggested PREP1 as a novel target of resveratrol.

The Study of the Cytotoxicity, Proliferative and Microbiological Activity of the Medicated Chewing Gum with Ascorbic Acid and Lysozyme Hydrochloride Using Different Culture of Cells.

Medicated chewing gum with lysozyme hydrochloride and ascorbic acid as active pharmaceutical ingredients was developed for application in dentistry. The aim of this research was to study the cytotoxicity, proliferative, and microbiological activities of the active ingredients in different types of cell cultures. The preclinical study of active pharmaceutical ingredients and their combinations was carried out using culture lines such as HepG2 (human hepatocarcinoma cells), Hek293 (human embryonic kidney cells), and MAEC (mouse aortic endothelial cells). MTT assays were used to analyse cytotoxicity and proliferative activity, while the state of antioxidant protection was assessed by the content of sulfhydryl groups and catalase activity. The determination of lipid peroxidation products was based on the level of TBA-active products. As a microbiological model for studying the effect of the developed dental medicine on the ability of the oral cavity microorganisms to form biofilms, the following strains were used: Streptococcus mutans, Staphylococcus aureus, Staphylococcus epidermidis, Lactobacillus plantarum, and Candida albicans. The optical density of the formed biofilm was evaluated by the intensity of the experimental sample's colour on a StatFax 303 Plus photometer at a wavelength of 630 nm. The combination of ascorbic acid and lysozyme hydrochloride in the established concentrations (20 mg and 10 mg per 1 gum, respectively) resulted in a slight stimulation of cell proliferation without any toxic effects and increased antioxidant protection, preventing the development of oxidative stress. It was found that, in contrast to the separately used active substances, the combination of lysozyme hydrochloride and ascorbic acid inhibits the biofilm formation of all studied microorganisms and shows the ability to destroy diurnal biofilms of L. plantarum and fungi of the genus Candida, indicating potentiation and summation of the active pharmaceutical ingredients' composition effects in the developed dental medicine. Due to the observed positive pharmacological and microbiological action, the combination of lysozyme hydrochloride and ascorbic acid in the medicated chewing gum serves as a promising tool for the prevention and treatment of infectious and inflammatory diseases of the periodontium and mucous membranes and the prevention of caries.