Effects of Notch signalling pathway on the relationship between vascular endothelial dysfunction and endothelial stromal transformation in atherosclerosis

Generation of a novel ex-vivo model to study re-endothelialization

Endothelial dysfunction initiates the pathogenesis of a myriad of cardiovascular diseases, yet the precise underlying mechanisms remain unclear. Current model utilises mechanical denudation of arteries resulting in an arterial-injury model with onset of intimal hyperplasia (IH). Our study shows that 5 min enzymatic denudation of human umbilical artery (hUA) lumen at 37 °C efficiently denudes hUA while maintaining vessel integrity without significantly increase intima-media thickness after 7 days in culture. This ex-vivo model will be a valuable tool in understanding the mechanism of re-endothelialization prior to smooth muscle cells (SMC) activation thus placating IH at an early stage.

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

BACKGROUND

Endothelial-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.

METHODS

Isoproterenol (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).

RESULTS

Both 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.

CONCLUSIONS

Our 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.

Interleukin-22: a potential therapeutic target in atherosclerosis

BACKGROUND

Atherosclerosis is recognized as a chronic immuno-inflammatory disease that is characterized by the accumulation of immune cells and lipids in the vascular wall. In this review, we focus on the latest advance regarding the regulation and signaling pathways of IL-22 and highlight its impacts on atherosclerosis.

MAIN BODY

IL-22, an important member of the IL-10 family of cytokines, is released by cells of the adaptive and innate immune system and plays a key role in the development of inflammatory diseases. The binding of IL-22 to its receptor complex can trigger a diverse array of downstream signaling pathways, in particular the JAK/STAT, to induce the expression of chemokines and proinflammatory cytokines. Recently, numerous studies suggest that IL-22 is involved in the pathogenesis of atherosclerosis by regulation of VSMC proliferation and migration, angiogenesis, inflammatory response, hypertension, and cholesterol metabolism.

CONCLUSION

IL-22 promotes the development of atherosclerosis by multiple mechanisms, which may be a promising therapeutic target in the pathogenesis of atherosclerosis.

Overexpressed miR-335-5p reduces atherosclerotic vulnerable plaque formation in acute coronary syndrome

BACKGROUND

Acute coronary syndrome (ACS) may induce cardiovascular death. The correlation of mast cells related microRNAs (miRs) with risk of ACS has been investigated. We explored regulatory mechanism of miR-335-5p on macrophage innate immune response, atherosclerotic vulnerable plaque formation, and revascularization in ACS in relation to Notch signaling.

METHODS

ACS-related gene microarray was collected from Gene Expression Omnibus database. After different agomir or antagomir, or inhibitor of Notch signaling treatment, IL-6, IL-1β, TNF-α, MCP-1, ICAM-1, and VCAM-1 levels were tested in ACS mice. Additionally, Notch signaling-related genes and matrix metalloproteinases (MMPs) were measured after miR-335-5p interference. Finally, mouse atherosclerosis, lipid accumulation, and the collagen/vessel area ratio of plaque were determined.

RESULTS

miR-335-5p targeted JAG1 and mediated Notch signaling in ACS. miR-335-5p up-regulation and Notch signaling inhibition reduced expression of JAG1, Notch pathway-related genes, IL-6, IL-1β, TNF-α, MCP-1, ICAM-1, VCAM-1, and MMPs, but promote TIMP1 and TIMP2 expression. Additionally, vulnerable plaques were decreased and collagen fiber contents were observed to increase after miR-335-5p overexpression and Notch signaling inhibition.

CONCLUSIONS

Overexpression of miR-335-5p inhibited innate immune response of macrophage, reduced atherosclerotic vulnerable plaque formation, and promoted revascularization in ACS mice targeting JAG1 through Notch signaling.

Overexpressed miR-335-5p reduces atherosclerotic vulnerable plaque formation in acute coronary syndrome

BACKGROUND

Acute coronary syndrome (ACS) may induce cardiovascular death. The correlation of mast cells related microRNAs (miRs) with risk of ACS has been investigated. We explored regulatory mechanism of miR-335-5p on macrophage innate immune response, atherosclerotic vulnerable plaque formation, and revascularization in ACS in relation to Notch signaling.

METHODS

ACS-related gene microarray was collected from Gene Expression Omnibus database. After different agomir or antagomir, or inhibitor of Notch signaling treatment, IL-6, IL-1β, TNF-α, MCP-1, ICAM-1, and VCAM-1 levels were tested in ACS mice. Additionally, Notch signaling-related genes and matrix metalloproteinases (MMPs) were measured after miR-335-5p interference. Finally, mouse atherosclerosis, lipid accumulation, and the collagen/vessel area ratio of plaque were determined.

RESULTS

miR-335-5p targeted JAG1 and mediated Notch signaling in ACS. miR-335-5p up-regulation and Notch signaling inhibition reduced expression of JAG1, Notch pathway-related genes, IL-6, IL-1β, TNF-α, MCP-1, ICAM-1, VCAM-1, and MMPs, but promote TIMP1 and TIMP2 expression. Additionally, vulnerable plaques were decreased and collagen fiber contents were observed to increase after miR-335-5p overexpression and Notch signaling inhibition.

CONCLUSIONS

Overexpression of miR-335-5p inhibited innate immune response of macrophage, reduced atherosclerotic vulnerable plaque formation, and promoted revascularization in ACS mice targeting JAG1 through Notch signaling.

Characterization of differentially expressed plasma proteins in patients with acute myocardial infarction

Acute myocardial infarction (AMI) remains a leading cause of morbidity and mortality worldwide. Novel biomarkers are needed to identify NSTEMI in AMI patients. The study objective was to use proteomics to identify novel plasma biomarkers for STEMI and NSTEMI patients. iTRAQ analysis was performed on pooled samples from 8 healthy controls and 12 STEMI and 12 NSTEMI patients. Bioinformatics analysis identified 95 differentially expressed proteins that were differentially expressed in the plasma of AMI patients and healthy controls; 28 of these proteins were found in STEMI/Con (22 upregulated and 6 downregulated), 48 in NSTEMI/Con (12 upregulated and 36 downregulated), and 44 in NSTEMI/STEMI (11 upregulated and 33 downregulated). Protein network analysis was then performed using STRING software. Functional analysis revealed that the identified plasma proteins were mainly involved with carbon metabolism, toll-like receptor signaling pathway, and hypertrophic cardiomyopathy. Nine of the proteins (SSA1, MDH1, FCN2, GPI, S100A8, LBP, vinculin, VDBP, and RBP4) that changed levels during AMI progression were further validated by ELISA. The constructed plasma proteome could reflect the AMI pathogenesis molecular mechanisms and provide a method for the early identification of NSTEMI in AMI patients. SIGNIFICANCE: The aim of this study was to use proteomics to identify novel predictive plasma biomarkers for patients with acute myocardial infarction (AMI), which would allow for either identification of individuals at risk of an infarction, and early identification of NSTEMI in patients with AMI. Using an approach that combined iTRAQ with LC-MS/MS, we found 95 proteins that showed significant differences in expression levels among the AMI patients and healthy controls. The proteins SSA1, MDH1, FCN2, GPI, S100A8, LBP, vinculin, VDBP, and RBP4 were found to play crucial roles in the pathogenesis of AMI. Using bioinformatics analysis, we found that dysregulation of carbon metabolism, toll-like receptor signaling pathway, and hypertrophic cardiomyopathy may be the major driving forces for cardiac damage during myocardial infarction. However, further investigations are needed to verify the mechanisms involved in the development of AMI especially NSTEMI. Taken together, our findings lay the foundation for understanding the molecular mechanisms underlying the pathogenic processes of AMI, and suggest potential applications for specific biomarkers in early diagnosis and determination of prognosis.

miR-133b Downregulation Reduces Vulnerable Plaque Formation in Mice with AS through Inhibiting Macrophage Immune Responses

Atherosclerosis (AS) is a chronic inflammatory disease characterized by accumulating deposition of lipids in the arterial intima. Notably, macrophages participate centrally in the pathogenesis of this deadly disease. In this study, we established AS mouse models in order to investigate the effect of microRNA-133b (miR-133b) on vulnerable plaque formation and vascular remodeling in AS and explore the potential functional mechanisms. The expression of miR-133b was altered or the Notch-signaling pathway was blocked in the AS mouse models in order to evaluate the proliferation, migration, and apoptosis of macrophages. It was observed that miR-133b was upregulated in AS, which might target MAML1 to regulate the Notch-signaling pathway. AS mice with downregulated miR-133b or inhibited Notch-signaling pathway presented with a reduced AS plaque area, a decreased positive rate of macrophages, and an increased positive rate of vascular smooth muscle cells. Moreover, Notch-signaling pathway blockade or miR-133b downregulation inhibited the macrophage viability and migration and accelerated the apoptosis. This study provides evidence that downregulated miR-133b expression may inhibit the immune responses of macrophages and attenuate the vulnerable plaque formation and vascular remodeling in AS mice through the MAML1-mediated Notch-signaling pathway, highlighting miR-133b as a novel therapeutic target for AS.