Low shear stress inhibits endothelial mitophagy via caveolin-1/miR-7-5p/SQSTM1 signaling pathway

The multifaceted role of macrophage mitophagy in SiO2-induced pulmonary fibrosis: A brief review

Prolonged exposure to environments with high concentrations of crystalline silica (CS) can lead to silicosis. Macrophages play a crucial role in the pathogenesis of silicosis. In the process of silicosis, silica (SiO2) invades alveolar macrophages (AMs) and induces mitophagy which usually exists in three states: normal, excessive, and/or deficiency. Different mitophagy states lead to corresponding toxic responses, including successful macrophage repair, injury, necrosis, apoptosis, and even pulmonary fibrosis. This is a complex process accompanied by various cytokines. Unfortunately, the details have not been fully systematically summarized. Therefore, it is necessary to elucidate the role of macrophage mitophagy in SiO2-induced pulmonary fibrosis by systematic analysis on the literature reports. In this review, we first summarized the current data on the macrophage mitophagy in the development of SiO2-induced pulmonary fibrosis. Then, we introduce the molecular mechanism on how SiO2-induced mitophagy causes pulmonary fibrosis. Finally, we focus on introducing new therapies based on newly developed mitophagy-inducing strategies. We conclude that macrophage mitophagy plays a multifaceted role in the progression of SiO2-induced pulmonary fibrosis, and reprogramming the macrophage mitophagy state accordingly may be a potential means of preventing and treating pulmonary fibrosis.

The Pathological Factors Involved in Current In Vitro Atherosclerotic Models

Cardiovascular disease stemmed from atherosclerosis (AS) is well recognized to be the predominant cause of global death. To comprehensively clarify the pathogenesis of AS, exploit effective drugs, as well as develop therapeutic solutions, various atherosclerotic models were constructed in vitro and widely utilized by the scientific community. Compared with animal models, the in vitro atherosclerotic models play a prominent role not only in the targeted research of single pathological factor related to AS in the human derived system, but also in the combined study on multipathological factors leading to AS, thereby contributing tremendously to the in-depth elucidation of atherosclerotic pathological process. In the current review, a variety of pathological factors incorporated into the existing atherosclerotic models in vitro are broadly elaborated, including the pathological mechanism, in vitro simulation approaches, and the desired improvement perspectives for reproducing each pathological factor. In addition, this review also summarizes the advantages and disadvantages of current atherosclerotic models as well as their potential functionality. Finally, the promising aspects for future atherosclerotic models in vitro with potential advances are also discussed.

Epigenetics in the formation of pathological aggregates in amyotrophic lateral sclerosis

The progressive degeneration of motor neurons in amyotrophic lateral sclerosis (ALS) is accompanied by the formation of a broad array of cytoplasmic and nuclear neuronal inclusions (protein aggregates) largely containing RNA-binding proteins such as TAR DNA-binding protein 43 (TDP-43) or fused in sarcoma/translocated in liposarcoma (FUS/TLS). This process is driven by a liquid-to-solid phase separation generally from proteins in membrane-less organelles giving rise to pathological biomolecular condensates. The formation of these protein aggregates suggests a fundamental alteration in the mRNA expression or the levels of the proteins involved. Considering the role of the epigenome in gene expression, alterations in DNA methylation, histone modifications, chromatin remodeling, non-coding RNAs, and RNA modifications become highly relevant to understanding how this pathological process takes effect. In this review, we explore the evidence that links epigenetic mechanisms with the formation of protein aggregates in ALS. We propose that a greater understanding of the role of the epigenome and how this inter-relates with the formation of pathological LLPS in ALS will provide an attractive therapeutic target.

The Role of Endothelial Cell Mitophagy in Age-Related Cardiovascular Diseases

Aging is a major risk factor for cardiovascular diseases (CVD), and mitochondrial autophagy impairment is considered a significant physiological change associated with aging. Endothelial cells play a crucial role in maintaining vascular homeostasis and function, participating in various physiological processes such as regulating vascular tone, coagulation, angiogenesis, and inflammatory responses. As aging progresses, mitochondrial autophagy impairment in endothelial cells worsens, leading to the development of numerous cardiovascular diseases. Therefore, regulating mitochondrial autophagy in endothelial cells is vital for preventing and treating age-related cardiovascular diseases. However, there is currently a lack of systematic reviews in this area. To address this gap, we have written this review to provide new research and therapeutic strategies for managing aging and age-related cardiovascular diseases.

Autophagy Induced by Low Shear Stress Leads to Endothelial Glycocalyx Disruption

INTRODUCTION

Previous studies have confirmed that low shear stress (LSS) induces glycocalyx disruption, leading to endothelial dysfunction. However, the role of autophagy in LSS-induced glycocalyx disruption and relevant mechanism are not clear. In this study, we hypothesized that LSS may promote autophagy, disrupting the endothelium glycocalyx.

METHODS

Human umbilical vein endothelial cells were subjected to physiological shear stress and LSS treatments, followed by the application of autophagy inducers and inhibitors. Additionally, cells were treated with specific matrix metalloproteinase-2 (MMP-2) and matrix metalloproteinase-9 (MMP-9) inhibitor. The expression of autophagic markers, glycocalyx, MMP-2, and MMP-9 was measured.

RESULTS

LSS impacted the expression of endothelium autophagy markers, increasing the expression of LC3II.LC3I-1 and Beclin-1, and decreasing the levels of p62, accompanied by glycocalyx disturbance. Moreover, LSS upregulated the expression of MMP-2 and MMP-9 and downregulated the levels of syndecan-1 and heparan sulfate (HS). Additionally, expression of MMP-2 and MMP-9 was increased by an autophagy promoter but was decreased by autophagy inhibitor treatment under LSS. Autophagy and MMP-2 and MMP-9 further caused glycocalyx disruption.

CONCLUSION

LSS promotes autophagy, leading to glycocalyx disruption. Autophagy increases the expression of MMP-2 and MMP-9, which are correlated with the glycocalyx destruction induced by LSS.

Recent Advancement in Elimination Strategies and Potential Rejuvenation Targets of Senescence

Cellular senescence is a state of exiting the cell cycle, resisting apoptosis, and changing phenotype. Senescent cells (SCs) can be identified by large, distorted morphology and irreversible inability to replicate. In early development, senescence has beneficial roles like tissue patterning and wound healing, where SCs are cleared by the immune system. However, there is a steep rise in SC number as organisms age. The issue with SC accumulation stems from the loss of cellular function, alterations of the microenvironment, and secretions of pro-inflammatory molecules, consisting of cytokines, chemokines, matrix metalloproteinases (MMPs), interleukins, and extracellular matrix (ECM)-associated molecules. This secreted cocktail is referred to as the senescence-associated secretory phenotype (SASP), a hallmark of cellular senescence. The SASP promotes inflammation and displays a bystander effect where paracrine signaling turns proliferating cells into senescent states. To alleviate age-associated diseases, researchers have developed novel methods and techniques to selectively eliminate SCs in aged individuals. Although studies demonstrated that selectively killing SCs improves age-related disorders, there are drawbacks to SC removal. Considering favorable aspects of senescence in the body, this paper reviews recent advancements in elimination strategies and potential rejuvenation targets of senescence to bring researchers in the field up to date.

The Role of microRNAs in Gene Expression and Signaling Response of Tumor Cells to an Acidic Environment

Many tumors are characterized by marked extracellular acidosis due to increased glycolytic metabolism, which affects gene expression and thereby tumor biological behavior. At the same time, acidosis leads to altered expression of several microRNAs (Mir7, Mir183, Mir203, Mir215). The aim of this study was to analyze whether the acidosis-induced changes in cytokines and tumor-related genes are mediated via pH-sensitive microRNAs. Therefore, the expression of Il6, Nos2, Ccl2, Spp1, Tnf, Acat2, Aox1, Crem, Gls2, Per3, Pink1, Txnip, and Ypel3 was examined in acidosis upon simultaneous transfection with microRNA mimics or antagomirs in two tumor lines in vitro and in vivo. In addition, it was investigated whether microRNA expression in acidosis is affected via known pH-sensitive signaling pathways (MAPK, PKC, PI3K), via ROS, or via altered intracellular Ca2+ concentration. pH-dependent microRNAs were shown to play only a minor role in modulating gene expression. Individual genes (e.g., Ccl2, Txnip, Ypel3) appear to be affected by Mir183, Mir203, or Mir215 in acidosis, but these effects are cell line-specific. When examining whether acid-dependent signaling affects microRNA expression, it was found that Mir203 was modulated by MAPK and ROS, Mir7 was affected by PKC, and Mir215 was dependent on the intracellular Ca2+ concentration. Mir183 could be increased by ROS scavenging. These correlations could possibly result in new therapeutic approaches for acidotic tumors.

Physiological functions of caveolae in endothelium

Endothelial caveolae are essential for a wide range of physiological processes and have emerged as key players in vascular biology. Our understanding of caveolar biology in endothelial cells has expanded dramatically since their discovery revealing critical roles in mechanosensation, signal transduction, eNOS regulation, lymphatic transport, and metabolic disease progression. Furthermore, caveolae are involved in the organization of membrane domains, regulation of membrane fluidity, and endocytosis which contribute to endothelial function and integrity. Additionally, recent advances highlight the impact of caveolae-mediated signaling pathways on vascular homeostasis and pathology. Together, the diverse roles of caveolae discussed here represent a breadth of cellular functions presenting caveolae as a defining feature of endothelial form and function. In light of these new insights, targeting caveolae may hold potential for the development of novel therapeutic strategies to treat a range of vascular diseases.

Comprehensive analysis of mitophagy-related genes in diagnosis and heterogeneous endothelial cells in chronic rhinosinusitis: based on bulk and single-cell RNA sequencing data

Background: Chronic rhinosinusitis (CRS) is a complex inflammatory disorder affecting the nasal and paranasal sinuses. Mitophagy, the process of selective mitochondrial degradation via autophagy, is crucial for maintaining cellular balance. However, the role of mitophagy in CRS is not well-studied. This research aims to examine the role of mitophagy-related genes (MRGs) in CRS, with a particular focus on the heterogeneity of endothelial cells (ECs). Methods: We employed both bulk and single-cell RNA sequencing data to investigate the role of MRGs in CRS. We compiled a combined database of 92 CRS samples and 35 healthy control samples from the Gene Expression Omnibus (GEO) database and we explored the differential expression of MRGs between them. A logistic regression model was built based on seven key genes identified through Random Forests and Support Vector Machines - Recursive Feature Elimination (SVM-RFE). Consensus cluster analysis was used to categorize CRS patients based on MRG expression patterns and weighted gene co-expression network analysis (WGCNA) was performed to find modules of highly correlated genes of the different clusters. Single-cell RNA sequencing data was utilized to analyze MRGs and EC heterogeneity in CRS. Results: Seven hub genes-SQSTM1, SRC, UBA52, MFN2, UBC, RPS27A, and ATG12-showed differential expression between two groups. A diagnostic model based on hub genes showed excellent prognostic accuracy. A strong positive correlation was found between the seven hub MRGs and resting dendritic cells, while a significant negative correlation was observed with mast cells and CD8+ T cells. CRS could be divided into two subclusters based on MRG expression patterns. WGCNA analysis identified modules of highly correlated genes of these two different subclusters. At the single-cell level, two types of venous ECs with different MRG scores were identified, suggesting their varying roles in CRS pathogenesis, especially in the non-eosinophilic CRS subtype. Conclusion: Our comprehensive study of CRS reveals the significant role of MRGs and underscores the heterogeneity of ECs. We highlighted the importance of Migration Inhibitory Factor (MIF) and TGFb pathways in mediating the effects of mitophagy, particularly the MIF. Overall, our findings enhance the understanding of mitophagy in CRS, providing a foundation for future research and potential therapeutic developments.

Caveolin-1 in endothelial cells: A potential therapeutic target for atherosclerosis

Atherosclerosis (AS) is a chronic vascular disease characterized by lipid accumulation and the activation of the inflammatory response; it remains the leading nation-wide cause of death. Early in the progression of AS, stimulation by pro-inflammatory agonists (TNF-α, LPS, and others), oxidized lipoproteins (ox-LDL), and biomechanical stimuli (low shear stress) lead to endothelial cell activation and dysfunction. Consequently, it is crucial to investigate how endothelial cells respond to different stressors and ways to alter endothelial cell activation in AS development, as they are the earliest cells to respond. Caveolin-1 (Cav1) is a 21-24-kDa membrane protein located in caveolae and highly expressed in endothelial cells, which plays a vital role in regulating lipid transport, inflammatory responses, and various cellular signaling pathways and has atherogenic effects. This review summarizes recent studies on the structure and physiological functions of Cav1 and outlines the potential mechanisms it mediates in AS development. Included are the roles of Cav1 in the regulation of endothelial cell autophagy, response to shear stress, modulation of the eNOS/NO axis, and transduction of inflammatory signaling pathways. This review provides a rationale for proposing Cav1 as a novel target for the prevention of AS, as well as new ideas for therapeutic strategies for early AS.

Unbalanced Redox With Autophagy in Cardiovascular Disease

Precise redox balance is essential for the optimum health and physiological function of the human body. Furthermore, an unbalanced redox state is widely believed to be part of numerous diseases, ultimately resulting in death. In this review, we discuss the relationship between redox balance and cardiovascular disease (CVD). In various animal models, excessive oxidative stress has been associated with increased atherosclerotic plaque formation, which is linked to the inflammation status of several cell types. However, various antioxidants can defend against reactive oxidative stress, which is associated with an increased risk of CVD and mortality. The different cardiovascular effects of these antioxidants are presumably due to alterations in the multiple pathways that have been mechanistically linked to accelerated atherosclerotic plaque formation, macrophage activation, and endothelial dysfunction in animal models of CVD, as well as in in vitro cell culture systems. Autophagy is a regulated cell survival mechanism that removes dysfunctional or damaged cellular organelles and recycles the nutrients for the generation of energy. Furthermore, in response to atherogenic stress, such as the generation of reactive oxygen species, oxidized lipids, and inflammatory signaling between cells, autophagy protects against plaque formation. In this review, we characterize the broad spectrum of oxidative stress that influences CVD, summarize the role of autophagy in the content of redox balance-associated pathways in atherosclerosis, and discuss potential therapeutic approaches to target CVD by stimulating autophagy.

Exercise protects aged mice against coronary endothelial senescence via FUNDC1-dependent mitophagy

Vascular aging contributes to adverse changes in organ function and is a significant indicator of major cardiac events. Endothelial cells (ECs) participate in aging-provoked coronary vascular pathology. Regular exercise is associated with preservation of arterial function with aging in humans. However, the molecular basis is not well understood. The present study was aimed to determine the effects of exercise on coronary endothelial senescence and whether mitochondrial clearance regulator FUN14 domain containing 1 (FUNDC1)-related mitophagy and mitochondrial homeostasis were involved. In mouse coronary arteries, FUNDC1 levels showed gradually decrease with age. Both FUNDC1 and mitophagy levels in cardiac microvascular endothelial cells (CMECs) were significantly reduced in aged mice and were rescued by exercise training. Exercise also alleviated CMECs senescence as evidenced by senescence associated β-galactosidase activity and aging markers, prevented endothelial abnormal cell migration, proliferation, and eNOS activation in CMECs from aged mice, and improved endothelium-dependent vasodilation of coronary artery, reduced myocardial neutrophil infiltration and inflammatory cytokines evoked by MI/R, restored angiogenesis and consequently alleviated MI/R injury in aging. Importantly, FUNDC1 deletion abolished the protective roles of exercise and FUNDC1 overexpression in ECs with adeno-associated virus (AAV) reversed endothelial senescence and prevented MI/R injury. Mechanistically, PPARγ played an important role in regulating FUNDC1 expressions in endothelium under exercise-induced laminar shear stress. In conclusion, exercise prevents endothelial senescence in coronary arteries via increasing FUNDC1 in a PPARγ-dependent manner, and subsequently protects aged mice against MI/R injury. These findings highlight FUNDC1-mediated mitophagy as potential therapeutic target that prevents endothelial senescence and myocardial vulnerability.