TG haplotype in the LRP8 is associated with myocardial infarction in south Indian population

ApoE Receptor-2 R952Q Variant in Macrophages Elevates Soluble LRP1 to Potentiate Hyperlipidemia and Accelerate Atherosclerosis in Mice

BACKGROUND

apoER2 (apolipoprotein E receptor-2) is a transmembrane receptor in the low-density lipoprotein receptor (LDLR) family with unique tissue expression. A single-nucleotide polymorphism that encodes the R952Q sequence variant has been associated with elevated plasma cholesterol levels and increased myocardial infarction risk in humans. The objective of this study was to delineate the mechanism underlying the association between the apoER2 variant with arginine-to-glutamine substitution at residue 952 (R952Q) and increased atherosclerosis risk.

METHODS

An apoER2 R952Q mouse model was generated and intercrossed with LDLR knockout mice, followed by feeding a Western-type high-fat high-cholesterol diet for 16 weeks. Atherosclerosis was investigated by immunohistology. Plasma lipids and lipid distributions among the various lipoprotein classes were analyzed by colorimetric assay. Tissue-specific effects of the R952Q sequence variant on atherosclerosis were analyzed by bone marrow transplant studies. sLRP1 (soluble low-density lipoprotein receptor-related protein 1) was measured in plasma and conditioned media from bone marrow-derived macrophages by ELISA and GST-RAP (glutathione S-transferase-receptor-associated protein) pull-down, respectively. P38 MAPK (mitogen-activated protein kinase) phosphorylation in VLDL (very-low-density lipoprotein)-treated macrophages was determined by Western blot analysis.

RESULTS

Consistent with observations in humans with this sequence variant, the apoER2 R952Q mutation exacerbated diet-induced hypercholesterolemia, via impediment of plasma triglyceride-rich lipoprotein clearance, to accelerate atherosclerosis in Western diet-fed LDLR knockout mice. Reciprocal bone marrow transplant experiments revealed that the apoER2 R952Q mutation in bone marrow-derived cells instead of non-bone marrow-derived cells was responsible for the increase in hypercholesterolemia and atherosclerosis. Additional data showed that the apoER2 R952Q mutation in macrophages promotes VLDL-induced LRP1 (low-density lipoprotein receptor-related protein 1) shedding in a p38 MAPK-dependent manner.

CONCLUSIONS

The apoER2 R952Q mouse model recapitulates characteristics observed in human disease. The underlying mechanism is that the apoER2 R952Q mutation in macrophages exacerbates VLDL-stimulated sLRP1 production in a p38 MAPK-dependent manner, resulting in its competition with cell surface LRP1 to impede triglyceride-rich lipoprotein clearance, thereby resulting in increased hypercholesterolemia and accelerated atherosclerosis.

From multi-omics approaches to personalized medicine in myocardial infarction

Myocardial infarction (MI) is a prevalent cardiovascular disease characterized by myocardial necrosis resulting from coronary artery ischemia and hypoxia, which can lead to severe complications such as arrhythmia, cardiac rupture, heart failure, and sudden death. Despite being a research hotspot, the etiological mechanism of MI remains unclear. The emergence and widespread use of omics technologies, including genomics, transcriptomics, proteomics, metabolomics, and other omics, have provided new opportunities for exploring the molecular mechanism of MI and identifying a large number of disease biomarkers. However, a single-omics approach has limitations in understanding the complex biological pathways of diseases. The multi-omics approach can reveal the interaction network among molecules at various levels and overcome the limitations of the single-omics approaches. This review focuses on the omics studies of MI, including genomics, epigenomics, transcriptomics, proteomics, metabolomics, and other omics. The exploration extended into the domain of multi-omics integrative analysis, accompanied by a compilation of diverse online resources, databases, and tools conducive to these investigations. Additionally, we discussed the role and prospects of multi-omics approaches in personalized medicine, highlighting the potential for improving diagnosis, treatment, and prognosis of MI.

miR-1322 protects against the myocardial ischemia via LRP8/PI3K/AKT pathway

INTRODUCTION

Myocardial infarction is a fatal disease that causes millions of deaths worldwide every year. The damage and recovery of cardiomyocytes are closely related to changes in gene expression. miRNA may be a new therapeutic target of myocardial ischemia-reperfusion.

METHODS

The differential expression genes were analyzed based on GSE83500, GSE60993 and GSE154733. miRNA expression profile data and clinical data were downloaded from GSE76591. Bioinformatics analysis including limma package, cluster analysis, WGCNA analysis were performed. H9c2 cell hypoxia model and mouse myocardial ischemia model were established. Q-PCR, Western blot and luciferase assay were carried out.

RESULTS

miR-1322 was identified as a significantly differentially expressed miRNA in myocardial ischemi. Yin Yang 1(YY1) was significantly highly expressed in cells with hypoxia treatment (P < 0.05), and myocardial ischemia mice (P < 0.01), which was identified as the transcription factor of miR-1322. The protein expression of LRP8 was lower in cells with hypoxia treatment and myocardial ischemia mice (P < 0.05) and LRP8 was the target gene of miR-1322. The overexpression of LRP8 could significantly increase the expression of p-PI3K, p-AKT, and P70 S6K (P < 0.05). LRP8 regulated PI3K/AKT/P70 S6K signaling pathway, eventually resulting in cell apoptosis.

CONCLUSION

Our results suggested that miR-1322 can protect against the myocardial ischemia via LRP8/PI3K/AKT pathway.

miR-362-3p suppresses ovarian cancer by inhibiting LRP8

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MiR-362-3p inhibited cell viability and proliferation of ovarian cancer cells.

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MiR-362-3p inhibited cell migration and invasion of ovarian cancer cells.

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MiR-362-3p inhibited OV growth in vivo.

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LRP8 was a target of miR-362-3p.

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MiR-362-3p targeting LRP8 repressed cell viability and proliferation of ovarian cancer cells.

Background

Ovarian cancer is one of the most common female cancers, with a high incidence worldwide. Aberrant expression of low‐density lipoprotein (LDL) receptor‐related protein 8 (LRP8) and microRNA (miR)-362-3p is involved in the pathogenesis of different cancers.

Methods

We aimed to elucidate the underlying mechanism of the miR-362-3p-LRP8 axis in ovarian cancer. Quantitative reverse transcription-polymerase chain reaction (qRT-PCR) was used to examine miR-362-3p and LRP8 expression in ovarian cancer tissues and cells. The luciferase assay was used to determine the relationship between miR-362-3p and LRP8. The function of overexpression of miR-362-3p and LRP8 was determined by assessing the cell viability using the cell counting kit 8 (CCK-8) assay, proliferation using 5′‑bromo-2′-deoxyuridine (BrdU) assay, migration using wound healing assay, invasion using transwell assay, and the protein expression levels of matrix metalloproteinase (MMP)-2, MMP9, and integrin α5 or β1 using western blotting assays in ovarian cancer cells.

Results

miR-362-3p expression levels were decreased in ovarian cancer tissues and cells and negatively correlated with LRP8 levels. Overexpression of miR-362-3p dramatically repressed cell growth. Furthermore, overexpression of LRP8 significantly facilitated the proliferation, migration, and invasion of ovarian cancer cells, which counteracted the inhibitory effect of miR-362-3p on ovarian cancer cell growth.

Conclusions

We reported that miR-362-3p hampered cell growth by repressing LRP8 expression in ovarian cancer cells. Our results provide new insights into ovarian cancer, involving both miR-362-3p and LRP8, which can be used as potential biomarkers for the treatment of ovarian cancer.

PCSK9 (Proprotein Convertase Subtilisin/Kexin Type 9) Triggers Vascular Smooth Muscle Cell Senescence and Apoptosis: Implication of Its Direct Role in Degenerative Vascular Disease

OBJECTIVE

PCSK9 (proprotein convertase subtilisin/kexin type 9) plays a critical role in cholesterol metabolism via the PCSK9-LDLR (low-density lipoprotein receptor) axis in the liver; however, evidence indicates that PCSK9 directly contributes to the pathogenesis of various diseases through mechanisms independent of its LDL-cholesterol regulation. The objective of this study was to determine how PCSK9 directly acts on vascular smooth muscle cells (SMCs), contributing to degenerative vascular disease. Approach and Results: We first examined the effects of PCSK9 on cultured human aortic SMCs. Overexpression of PCSK9 downregulated the expression of ApoER2 (apolipoprotein E receptor 2), a known target of PCSK9. Treatment with soluble recombinant human ApoER2 or the DNA synthesis inhibitor, hydroxyurea, inhibited PCSK9-induced polyploidization and other cellular responses of human SMCs. Treatment with antibodies against ApoER2 resulted in similar effects to those observed with PCSK9 overexpression. Inducible, SMC-specific knockout of Pcsk9 accelerated neointima formation in mouse carotid arteries and reduced age-related arterial stiffness. PCSK9 was expressed in SMCs of human atherosclerotic lesions and abundant in the "shoulder" regions of vulnerable atherosclerotic plaques. PCSK9 was also expressed in SMCs of abdominal aortic aneurysm, which was inversely related to the expression of smooth muscle α-actin.

CONCLUSIONS

Our findings demonstrate that PCSK9 inhibits proliferation and induces polyploidization, senescence, and apoptosis, which may be relevant to various degenerative vascular diseases.

Reelin Depletion Protects Against Atherosclerosis by Decreasing Vascular Adhesion of Leukocytes

[Figure: see text].

ApoER2 (Apolipoprotein E Receptor-2) Deficiency Accelerates Smooth Muscle Cell Senescence via Cytokinesis Impairment and Promotes Fibrotic Neointima After Vascular Injury

OBJECTIVE

Genome-wide studies showed that mutation in apoER2 (apolipoprotein E receptor-2) is additive with ε4 polymorphism in the APOE gene on cardiovascular disease risk in humans. ApoE or apoER2 deficiency also accelerates atherosclerosis lesion necrosis in hypercholesterolemic mice and promotes neointima formation after vascular injury. This study tests the hypothesis that apoE and apoER2 modulate vascular occlusive diseases through distinct mechanisms. Approach and Results: Carotid endothelial denudation induced robust neointima formation in both apoE-/- and apoER2-deficient Lrp8-/- mice. The intima in apoE-/- mice was rich in smooth muscle cells, but the intima in Lrp8-/- mice was cell-poor and rich in extracellular matrix. Vascular smooth muscle cells isolated from apoE-/- mice were hyperplastic whereas Lrp8-/- smooth muscle cells showed reduced proliferation but responded robustly to TGF (transforming growth factor)-β-induced fibronectin synthesis indicative of a senescence-associated secretory phenotype, which was confirmed by increased β-galactosidase activity, p16INK4a immunofluorescence, and number of multinucleated cells. Western blot analysis of cell cycle-associated proteins showed that apoER2 deficiency promotes cell cycle arrest at the metaphase/anaphase. Coimmunoprecipitation experiments revealed that apoER2 interacts with the catalytic subunit of protein phosphatase 2A. In the absence of apoER2, PP2A-C (protein phosphatase 2A catalytic subunit) failed to interact with CDC20 (cell-division cycle protein 20) thus resulting in inactive anaphase-promoting complex and impaired cell cycle exit.

CONCLUSIONS

This study showed that apoER2 participates in APC (anaphase-promoting complex)/CDC20 complex formation during mitosis, and its absence impedes cytokinesis abscission thereby accelerating premature cell senescence and vascular disease. This mechanism is distinct from apoE deficiency, which causes smooth muscle cell hyperplasia to accelerate vascular disease.

A haplotype of the phosphodiesterase 4D (PDE4D) gene is associated with myocardial infarction and with cardiometabolic parameters: the GEA study

The phosphodiesterase family is involved in a wide spectrum of diseases, including ischemic stroke. However, few studies have analyzed the relationship between phosphodiesterase 4D (PDE4D) and myocardial infarction (MI). Therefore, the aim of this research was to evaluate the association of the PDE4D gene polymorphisms with MI, and with cardiometabolic parameters in the Mexican population. Six polymorphisms (rs2910829, rs1423246, rs966221, rs4502776, rs13172481, and rs6869495) were genotyped in 1023 MI patients and 1105 healthy controls. A similar distribution of the six polymorphisms was observed in both studied groups. However, after evaluating the linkage disequilibrium, we detected a risk haplotype for MI (AGAGAA; OR = 1.148; P = 0.025). In addition, the polymorphisms were associated with the presence of some clinical and metabolic parameters (central obesity, hypertriglyceridemia, Aspartate transaminase >p75, Lipoprotein (a) >30 mg/dL, TAT >p75, fatty liver, and vitamin D <30 ng/dL) in healthy controls. The results suggest that in the Mexican population, a PDE4D haplotype is associated with increased risk of developing MI, and that PDE4D polymorphisms are independently associated with the presence of cardiometabolic parameters.