Programmed Cell Death of Endothelial Cells in Myocardial Infarction and Its Potential Therapeutic Strategy

Single-cell RNA sequencing reveals hub genes of myocardial infarction-associated endothelial cells

BACKGROUND

Myocardial infarction (MI) is a cardiovascular disease that seriously threatens human health. Dysangiogenesis of endothelial cells (ECs) primarily inhibits recovery from MI, but the specific mechanism remains to be further elucidated.

METHODS

In this study, the single-cell RNA-sequencing data from both MI and Sham mice were analyzed by the Seurat Package (3.2.2). The number of ECs in MI and Sham groups were compared by PCA and tSNE algorithm. FindMarkers function of Seurat was used to analyze the DEGs between the MI and Sham groups. Then, the ECs was further clustered into 8 sub-clusters for trajectory analysis. The BEAM was used to analyze the branch point 3 and cluster the results. In addition, the DEGs in the microarray data set of MI and Sham mice were cross-linked, and the cross-linked genes were used to construct PPI networks. The key genes with the highest degree were identified and analyzed for functional enrichment. Finally, this study cultured human umbilical vein endothelial cells (HUVECs), established hypoxia models, and interfered with hub gene expression in cells. The impact of hub genes on the migration and tube formation of hypoxic-induced HUVECs were verified by Wound healing assays and tubule formation experiments.

RESULTS

The number and proportion of ECs in the MI group were significantly lower than those in the Sham group. Meantime, 225 DEGs were found in ECs between the MI and Sham groups. Through trajectory analysis, EC4 was found to play an important role in MI. Then, by using BEAM to analyze the branch point 3, and clustering the results, a total of 495 genes were found to be highly expressed in cell Fate2 (mainly EC4). In addition, a total of 194 DEGs were identified in Micro array dataset containing both MI and Sham mice. The hub genes (Timp1 and Fn1) with the highest degree were identified. Inhibiting Timp1 and Fn1 expression promoted the migration and tube formation of HUVECs.

CONCLUSIONS

Our data highlighted the non-linear dynamics of ECs in MI, and provided a foothold for analyzing cardiac homeostasis and pro-angiogenesis in MI.

Ferroptosis Involved in Cardiovascular Diseases: Mechanism Exploration of Ferroptosis' Role in Common Pathological Changes

ABSTRACT

Regulated cell death is a controlled form of cell death that protects cells by adaptive responses in pathophysiological states. Ferroptosis has been identified as a novel method of controlling cell death in recent years. Several cardiovascular diseases (CVDs) are shown to be profoundly influenced by ferroptosis, and ferroptosis is directly linked to the majority of cardiovascular pathological alterations. Despite this, it is still unclear how ferroptosis affects the pathogenic alterations that take place in CVDs. Based on a review of the mechanisms that regulate ferroptosis, this review explores the most recent research on the role of ferroptosis in the major pathological changes associated with CVDs, to provide new perspectives and strategies for cardiovascular research and clinical treatment.

The regulatory role and mechanism of USP14 in endothelial cell pyroptosis induced by coronary heart disease

OBJECTIVE

The present study probes into the role and mechanism of ubiquitin specific peptidase 14 (USP14) in coronary heart disease (CHD)-triggered endothelial cell pyroptosis.

METHODS

An in vitro CHD model was established by inducing human coronary artery endothelial cells (HCAECs) with oxidized low-density lipoprotein (ox-LDL). HCAECs were transfected with si-USP14, followed by evaluation of cell viability by CCK-8 assay, detection of lactate dehydrogenase (LDH) activity by assay kit, detection of USP14, miR-15b-5p, NLRP3, GSDMD-N, and Cleaved-Caspase-1 expressions by qRT-PCR or Western blot, as well as IL-1β and IL-18 concentrations by ELISA. Co-IP confirmed the binding between USP14 and NLRP3. The ubiquitination level of NLRP3 in cells was measured after protease inhibitor MG132 treatment. Dual-luciferase reporter assay verified the targeting relationship between miR-15b-5p and USP14.

RESULTS

USP14 and NLRP3 were highly expressed but miR-15b-5p was poorly expressed in ox-LDL-exposed HCAECs. USP14 silencing strengthened the viability of ox-LDL-exposed HCAECs, reduced the intracellular LDH activity, and diminished the NLRP3, GSDMD-N, Cleaved-Caspase-1, IL-1β, and IL-18 expressions. USP14 bound to NLRP3 protein and curbed its ubiquitination. Repression of NLRP3 ubiquitination counteracted the inhibitory effect of USP14 silencing on HCAEC pyroptosis. miR-15b-5p restrained USP14 transcription and protein expression. miR-15b-5p overexpression alleviated HCAEC pyroptosis by suppressing USP14/NLRP3.

CONCLUSION

USP14 stabilizes NLRP3 protein expression through deubiquitination, thereby facilitating endothelial cell pyroptosis in CHD. miR-15b-5p restrains endothelial cell pyroptosis by targeting USP14 expression.

Reduction in mitochondrial ROS improves oxidative phosphorylation and provides resilience to coronary endothelium in non-reperfused myocardial infarction

Recent studies demonstrated that mitochondrial antioxidant MnSOD that reduces mitochondrial (mito) reactive oxygen species (ROS) helps maintain an optimal balance between sub-cellular ROS levels in coronary vascular endothelial cells (ECs). However, it is not known whether EC-specific mito-ROS modulation provides resilience to coronary ECs after a non-reperfused acute myocardial infarction (MI). This study examined whether a reduction in endothelium-specific mito-ROS improves the survival and proliferation of coronary ECs in vivo. We generated a novel conditional binary transgenic animal model that overexpresses (OE) mitochondrial antioxidant MnSOD in an EC-specific manner (MnSOD-OE). EC-specific MnSOD-OE was validated in heart sections and mouse heart ECs (MHECs). Mitosox and mito-roGFP assays demonstrated that MnSOD-OE resulted in a 50% reduction in mito-ROS in MHEC. Control and MnSOD-OE mice were subject to non-reperfusion MI surgery, echocardiography, and heart harvest. In post-MI hearts, MnSOD-OE promoted EC proliferation (by 2.4 ± 0.9 fold) and coronary angiogenesis (by 3.4 ± 0.9 fold), reduced myocardial infarct size (by 27%), and improved left ventricle ejection fraction (by 16%) and fractional shortening (by 20%). Interestingly, proteomic and Western blot analyses demonstrated upregulation in mitochondrial complex I and oxidative phosphorylation (OXPHOS) proteins in MnSOD-OE MHECs. These MHECs also showed increased mitochondrial oxygen consumption rate (OCR) and membrane potential. These findings suggest that mito-ROS reduction in EC improves coronary angiogenesis and cardiac function in non-reperfused MI, which are associated with increased activation of OXPHOS in EC-mitochondria. Activation of an energy-efficient mechanism in EC may be a novel mechanism to confer resilience to coronary EC during MI.