Mechanisms of Regenerative Potential Activation in Cardiac Mesenchymal Cells

Molecular Interplay in Cardiac Fibrosis: Exploring the Functions of RUNX2, BMP2, and Notch

Cardiac fibrosis, characterized by the excessive deposition of extracellular matrix proteins, significantly contributes to the morbidity and mortality associated with cardiovascular diseases. This article explores the complex interplay between Runt-related transcription factor 2 (RUNX2), bone morphogenetic protein 2 (BMP2), and Notch signaling pathways in the pathogenesis of cardiac fibrosis. Each of these pathways plays a crucial role in the regulation of cellular functions and interactions that underpin fibrotic processes in the heart. Through a detailed review of current research, we highlight how the crosstalk among RUNX2, BMP2, and Notch not only facilitates our understanding of the fibrotic mechanisms but also points to potential biomolecular targets for intervention. This article delves into the regulatory networks, identifies key molecular mediators, and discusses the implications of these signaling pathways in cardiac structural remodeling. By synthesizing findings from recent studies, we provide insights into the cellular and molecular mechanisms that could guide future research directions, aiming to uncover new therapeutic strategies to manage and treat cardiac fibrosis effectively.

Calciprotein Particles Induce Cellular Compartment-Specific Proteome Alterations in Human Arterial Endothelial Cells

Calciprotein particles (CPPs) are indispensable scavengers of excessive Ca2+ and PO43- ions in blood, being internalised and recycled by liver and spleen macrophages, monocytes, and endothelial cells (ECs). Here, we performed a pathway enrichment analysis of cellular compartment-specific proteomes in primary human coronary artery ECs (HCAEC) and human internal thoracic artery ECs (HITAEC) treated with primary (amorphous) or secondary (crystalline) CPPs (CPP-P and CPPs, respectively). Exposure to CPP-P and CPP-S induced notable upregulation of: (1) cytokine- and chemokine-mediated signaling, Ca2+-dependent events, and apoptosis in cytosolic and nuclear proteomes; (2) H+ and Ca2+ transmembrane transport, generation of reactive oxygen species, mitochondrial outer membrane permeabilisation, and intrinsic apoptosis in the mitochondrial proteome; (3) oxidative, calcium, and endoplasmic reticulum (ER) stress, unfolded protein binding, and apoptosis in the ER proteome. In contrast, transcription, post-transcriptional regulation, translation, cell cycle, and cell-cell adhesion pathways were underrepresented in cytosol and nuclear compartments, whilst biosynthesis of amino acids, mitochondrial translation, fatty acid oxidation, pyruvate dehydrogenase activity, and energy generation were downregulated in the mitochondrial proteome of CPP-treated ECs. Differentially expressed organelle-specific pathways were coherent in HCAEC and HITAEC and between ECs treated with CPP-P or CPP-S. Proteomic analysis of mitochondrial and nuclear lysates from CPP-treated ECs confirmed bioinformatic filtration findings.

Interplay between BMP2 and Notch signaling in endothelial-mesenchymal transition: implications for cardiac fibrosis

Background

The endothelial-to-mesenchymal transition (EndoMT) is a crucial process in cardiovascular development and disorders. Cardiac fibrosis, characterized by excessive collagen deposition, occurs in heart failure, leading to the organ remodeling. Embryonic signaling pathways such as bone morphogenetic protein 2 (BMP2) and Notch are involved in its regulation. However, the interplay between these pathways in EndoMT remains unclear.

Methods

This study investigates the downstream targets of Notch and BMP2 and their effect on EndoMT markers in cardiac mesenchymal cells (CMCs) and human umbilical vein endothelial cells (HUVECs). We transduced cell cultures with vectors carrying intracellular domain of NOTCH1 (NICD) and/or BMP2 and evaluated gene expression and activation of EndoMT markers.

Results

The results suggest that the Notch and BMP2 signaling pathways have common downstream targets that regulate EndoMT. The activation of BMP2 and Notch is highly dependent on cell type, and co-cultivation of CMCs and HUVECs produced opposing cellular responses to target gene expression and α-smooth muscle actin (α-SMA) synthesis.

Conclusions

The balance between Notch and BMP2 signaling determines the outcome of EndoMT and fibrosis in the heart. The study's findings highlight the need for further research to understand the interaction between Notch and BMP2 in the heart and develop new therapeutic strategies for treating cardiac fibrosis.

Editorial of the Special Issue: Cellular Mechanisms of Cardiovascular Disease

Cardiovascular diseases (CVD) remain the major cause of mortality and disability worldwide, having contributed to 19 [...].

Gene expression patterns and related pathways in the hearts of rhesus monkeys subjected to prolonged myocardial ischemia

After myocardial infarction (MI) occurs, progressive pathological cardiac remodeling results in heart dysfunction and even heart failure during the following months or years. The present study explored the molecular mechanisms underlying the late phase of MI at the global transcript level. A rhesus monkey model of myocardial ischemia induced by left anterior descending (LAD) artery ligation was established, and the heart tissue was collected eight weeks after ligation for transcriptome analysis by DNA microarray technology. Differentially expressed genes in the core infarcted area and remote infarcted area of the ischemic heart were detected with significance analysis of microarray (SAM), and related pathways were detected by Gene Ontology (GO)/pathway analysis. We found that compared to the sham condition, prolonged ischemia increased the levels of 941 transcripts, decreased the levels of 380 transcripts in the core infarcted area, and decreased the levels of 8 transcripts in the remote area in monkey heart tissue. Loss of coordination between the expression of genes, including natriuretic peptide A (NPPA), NPPB, and corin (Corin, serine peptidase), may aggravate cardiac remodeling. Furthermore, imbalance in the enriched significantly changed pathways, including fibrosis-related pathways, cardioprotective pathways, and the cardiac systolic pathway, likely also plays a key role in regulating the development of heart remodeling.

A myocardial infarct border-zone-on-a-chip demonstrates distinct regulation of cardiac tissue function by an oxygen gradient

After a myocardial infarction, the boundary between the injured, hypoxic tissue and the adjacent viable, normoxic tissue, known as the border zone, is characterized by an oxygen gradient. Yet, the impact of an oxygen gradient on cardiac tissue function is poorly understood, largely due to limitations of existing experimental models. Here, we engineered a microphysiological system to controllably expose engineered cardiac tissue to an oxygen gradient that mimics the border zone and measured the effects of the gradient on electromechanical function and the transcriptome. The gradient delayed calcium release, reuptake, and propagation; decreased diastolic and peak systolic stress; and increased expression of inflammatory cascades that are hallmarks of myocardial infarction. These changes were distinct from those observed in tissues exposed to uniform normoxia or hypoxia, demonstrating distinct regulation of cardiac tissue phenotypes by an oxygen gradient. Our border-zone-on-a-chip model advances functional and mechanistic insight into oxygen-dependent cardiac tissue pathophysiology.

The Role of the Notch Signaling Pathway in Recovery of Cardiac Function after Myocardial Infarction

Myocardial infarction (MI) is a pathological process, evidencing as massive death of cardiomyocytes associated with hypoxic and oxidative stress. The formation of areas of fibrosis ultimately leads to heart failure. There are some mechanisms that contribute to the functional repair of the heart. In most mammals, including humans, the Notch signaling pathway has cardioprotective effects. It is involved in the formation of the heart in embryogenesis and in the restoration of cardiac function after MI due to: (1) reducing oxidative stress; (2) prevention of apoptosis; (3) regulation of inflammation; (4) containment of fibrosis and hypertrophy of cardiomyocytes; (5) tissue revascularization; and (6) regulation of proliferation and differentiation of cardiomyocytes. In addition, the Notch signaling pathway interacts with other signaling cascades involved in the pathogenesis of MI and subsequent cardiac repair. In this review, we consider the Notch signaling pathway as a potential target for therapeutic approaches aimed at improving cardiac recovery after MI.