Cholesterol crystals promote endothelial cell and monocyte interactions via H2O2-mediated PP2A inhibition, NFκB activation and ICAM1 and VCAM1 expression

Zedoarondiol inhibits monocyte adhesion and expression of VCAM and ICAM in endothelial cells induced by oxidative stress

Zedoarondiol, a newly discovered compound derived from the roots of zedoary turmeric, a traditional Chinese herb, has demonstrated potential in reducing inflammation of the vascular endothelium and safeguarding it from harm. Nonetheless, the precise mechanism underlying these effects remains to be elucidated. In this study, we established a model of HUVEC injury induced by hydrogen peroxide. We observed whether Zedoarondiol could reduce the adhesion and transendothelial migration (TEM) of inflammatory cells by inhibiting the expression of VCAM-1 and ICAM-1 in HUVECs. The research findings indicate that utilising Zedoarondiol resulted in a significant reduction in the adhesion rate of THP1 cells to HUVECs, leading to a more condensed cytoskeletal structure. Moreover, Zedoarondiol demonstrated a decrease in NF-κBβ-Ser536 phosphorylation levels in H2O2-stimulated human umbilical vein endothelial cells, resulting in a hindered capacity to bind to target genes like ICAM-1 and VCAM-1, This findings may provide a new pharmacological basis and scientific evidence for Zedoarondiol to slow the atherosclerosis progression by maintaining endothelial function.

Vascular smooth muscle cells in response to cholesterol crystals modulates inflammatory cytokines release and promotes neutrophil extracellular trap formation

BACKGROUND

The formation and accumulation of cholesterol crystals (CC) at the lesion site is a hallmark of atherosclerosis. Although studies have shown the importance of vascular smooth muscle cells (VSMCs) in the disease atherosclerosis, little is known about the molecular mechanism behind the uptake of CC in VSMCs and their role in modulating immune response.

METHODS

Human aortic smooth muscle cells were cultured and treated with CC. CC uptake and CC mediated signaling pathway and protein induction were studied using flow cytometry, confocal microscopy, western blot and Olink proteomics. Conditioned medium from CC treated VSMCs was used to study neutrophil adhesion, ROS production and phagocytosis. Neutrophil extracellular traps (NETs) formations were visualized using confocal microscopy.

RESULTS

VSMCs and macrophages were found around CC clefts in human carotid plaques. CC uptake in VSMCs are largely through micropinocytosis and phagocytosis via PI3K-AkT dependent pathway. The uptake of CC in VSMCs induce the release inflammatory proteins, including IL-33, an alarming cytokine. Conditioned medium from CC treated VSMCs can induce neutrophil adhesion, neutrophil reactive oxygen species (ROS) and neutrophil extracellular traps (NETs) formation. IL-33 neutralization in conditioned medium from CC treated VSMCs inhibited neutrophil ROS production and NETs formation.

CONCLUSION

We demonstrate that VSMCs due to its vicinity to CC clefts in human atherosclerotic lesion can modulate local immune response and we further reveal that the interaction between CC and VSMCs impart an inflammatory milieu in the atherosclerotic microenvironment by promoting IL-33 dependent neutrophil influx and NETs formation.

Effect of reactive oxygen, nitrogen, and sulfur species on signaling pathways in atherosclerosis

Atherosclerosis is a chronic inflammatory disease in which fats, lipids, cholesterol, calcium, proliferating smooth muscle cells, and immune cells accumulate in the intima of the large arteries, forming atherosclerotic plaques. A complex interplay of various vascular and immune cells takes place during the initiation and progression of atherosclerosis. Multiple reports indicate that tight control of reactive oxygen species (ROS), reactive nitrogen species (RNS), and reactive sulfur species (RSS) production is critical for maintaining vascular health. Unrestricted ROS and RNS generation may lead to activation of various inflammatory signaling pathways, facilitating atherosclerosis. Given these deleterious consequences, it is important to understand how ROS and RNS affect the signaling processes involved in atherogenesis. Conversely, RSS appears to exhibit an atheroprotective potential and can alleviate the deleterious effects of ROS and RNS. Herein, we review the literature describing the effects of ROS, RNS, and RSS on vascular smooth muscle cells, endothelial cells, and macrophages and focus on how changes in their production affect the initiation and progression of atherosclerosis. This review also discusses the contribution of ROS, RNS, and RSS in mediating various post-translational modifications, such as oxidation, nitrosylation, and sulfation, of the molecules involved in inflammatory signaling.

Biomimetic Nanocarriers of Pro-Resolving Lipid Mediators for Resolution of Inflammation in Atherosclerosis

Atherosclerosis (ATH) is a systemic disease characterized by a chronic inflammatory process and lipid deposition in the arterial walls. The chronic inflammation within ATH lesions results, at least in part, from the failed resolution of inflammation. This process is controlled actively by specialized pro-resolving lipid mediators (SPMs), namely lipoxins, resolvins, protectins, and maresins. Herein, biomimetic nanocarriers are produced comprising a cocktail of SPMs-loaded lipid nanoemulsions (LN) covered with macrophage membranes (Bio-LN/SPMs). Bio-LN/SPMs retain on their surface the macrophage receptors involved in cellular interactions and the "marker of self" CD47, which impede their recognition and uptake by other macrophages. The binding of Bio-LN/SPMs to the surface of endothelial cells (EC) and smooth muscle cells (SMC) is facilitated by the receptors on the macrophage membranes and partly by SPMs receptors. In addition, Bio-LN/SPMs prove functional by reducing monocyte adhesion and transmigration to/through activated EC and by stimulating macrophage phagocytic activity. After intravenous administration, Bio-LN/SPMs accumulate in the aorta of ApoE-deficient mice at the level of atherosclerotic lesions. Also, the safety assessment testing reveals no side effects or immunotoxicity of Bio-LN/SPMs. Thus, the newly developed Bio-LN/SPMs represent a reliable targeted nanomedicine for the resolution of inflammation in atherosclerosis.

Sirt4 deficiency promotes the development of atherosclerosis by activating the NF-κB/IκB/CXCL2/3 pathway

BACKGROUND AND AIMS

As a member of mitochondrial sirtuins, Sirt4 plays a vital role in cellular metabolism and intracellular signal transduction; however, its effect on atherosclerosis is unclear. This study aimed to explore the effect of Sirt4 on atherosclerosis and its underlying mechanism.

METHODS

In vivo, Apoe^-/- and Apoe^-/-/Sirt4^-/- mice were fed a high-fat diet to induce atherosclerosis. In vitro, peritoneal macrophages from two mouse types were extracted and treated with oxidized low-density lipoprotein to establish a cell model, THP-1 cells were used to observe the effect of Sirt4 on the adhesion ability of monocytes. The growth and composition of aortic plaques in two mouse types were analyzed by H&E staining, Oil Red O staining, Dil oxidized low-density lipoprotein, immunohistochemistry, real-time quantitative polymerase chain reaction and enzyme-linked immunosorbent assay. Transcriptome analysis and Western blotting were performed to explore the specific mechanism.

RESULTS

Sirt4 deficiency aggravated atherosclerosis in mice. In vivo, aortic plaque size, lipid content, and expression of related inflammatory factors in Apoe^-/-/Sirt4^-/- mice were higher than those in the control group, whereas the content of collagen Ⅰ and smooth muscle actin-α was significantly lower. Sirt4-deficient macrophages exhibited stronger lipid phagocytosis in vitro, and the adhesion ability of monocytes increased when Sirt4 expression decreased. Transcriptome analysis showed that the expression of CXCL2 and CXCL3 in Sirt4-deficient peritoneal macrophages increased significantly, which may play a role by activating the NF-κB pathway. In further analysis, the results in vitro and in vivo showed that the expression of VCAM-1 and pro-inflammatory factors, such as IL-6, TNF-α and IL-1β, increased, whereas the expression of anti-inflammatory factor IL-37 decreased in Sirt4-deficient peritoneal macrophages and tissues. After blocking the effect with NK-κB inhibitor BAY11-7082, the inflammatory reaction in sirt4 deficient macrophages was also significantly decreased.

CONCLUSIONS

This study demonstrates that Sirt4 deficiency promotes the development of atherosclerosis by activating the NF-κB/IκB/CXCL2/3 pathway, suggesting that Sirt4 may exhibit a protective effect in atherosclerosis, which provides a new strategy for clinical prevention and treatment of atherosclerosis.

Targeting VCAM-1: a therapeutic opportunity for vascular damage

INTRODUCTION

The vascular cell adhesion molecule (VCAM-1) is a transmembrane sialoglycoprotein detected in activated endothelial and vascular smooth muscle cells involved in the adhesion and transmigration of inflammatory cells into damaged tissue. Widely used as a pro-inflammatory marker, its potential role as a targeting molecule has not been thoroughly explored.

AREAS COVERED

We discuss the current evidence supporting the potential targeting of VCAM-1 in atherosclerosis, diabetes, hypertension and ischemia/reperfusion injury.

EXPERT OPINION

There is emerging evidence that VCAM-1 is more than a biomarker and may be a promising therapeutic target for vascular diseases. While there are neutralizing antibodies that allow preclinical research, the development of pharmacological tools to activate or inhibit this protein are required to thoroughly assess its therapeutic potential.

7-Methoxyisoflavone suppresses vascular endothelial inflammation by inhibiting the expression of endothelial adhesion molecules

Endothelial cells (ECs) are vital regulators of inflammatory processes, there is the potential for inhibition of EC inflammation to be a therapeutic target in chronic inflammatory diseases. This study aimed to investigate the effect of 7-methoxyisoflavone (7-Mif) on endothelial inflammation. Our results showed that 7-Mif have no cytotoxicity on HUVECs. Pretreatment with 5 μM, 10 μM and 50 μM 7-Mif significantly reduced IL-1β-induced ICAM-1 (28.1% ± 4.1%, 25.9 ± 2.5% and 32.0% ± 3.2%, respectively) and VCAM-1 (48.0% ± 5.6%, 40.1 ± 3.1% and 39.6% ± 3.1%, respectively) mRNA expression. And pretreatment with 10 μM and 50 μM 7-Mif significantly reduced IL-1β-induced ICAM-1 (45.1% ± 4.4% and 33.6 ± 4.4%, respectively) and VCAM-1 (53.0% ± 3.7% and 53.7 ± 5.1%, respectively) protein levels. Furthermore, pretreatment with 50 μM 7-Mif inhibited monocyte-endothelial cell adhesion (50.2% ± 4.2%). Mechanistically, our results showed that 7-Mif reversed IL-1β-induced NF-κB activation and p65 translocation to the nucleus, therefore inhibiting endothelial cell inflammation. In addition, we confirmed that 7-Mif 10 mg/kg and 20 mg/kg reduced LPS-induced ICAM-1 (47.3% ± 1.3% and 39.0% ± 3.2%, respectively) and VCAM-1 (56.5 ± 2.8% and 47.8 ± 4.3%, respectively) expression and attenuated inflammatory injury in mice. In conclusion, we showed the inhibitory effect of 7-Mif on endothelial inflammation by suppressing the expression of endothelial adhesion molecules and monocyte adhesion. Our data illustrated that 7-Mif could positively regulate the process of endothelial inflammation.

Cholesterol crystals activate NLRP3 inflammasomes and promote gallstone formation by increasing mucin secretion

Cholesterol crystals participate in cholesterol nucleation; however, the role of cholesterol crystals in gallstone development is unknown. Mucin secretion contributes to increased size of gallstones. Cholesterol crystals activate inflammasomes and participate in many sterile inflammation related human diseases. We investigated the role of cholesterol crystals and mucins in sterile inflammation and gallstone enlargement. We found that expression of mucin 5AC (MUC5AC), NOD-, LRR- and pyrin domain-containing protein 3 (NLRP3) and interleukin-1b (IL-1b) was increased significantly in tissues adjacent to gallstones. Experiments in vitro showed that cholesterol crystals promote MUC5AC secretion; they also increase expression of NLRP3, NLR family CARD domain-containing 4 (NLRC4), apoptosis-associated speck-like protein containing caspase recruitment domain (ASC), and cleaved caspase-1 in biliary epithelial cells. Inhibition of Inflammasomes by NLRP3, ASC or caspase-1 small interfering RNAs reduced MUC5AC secretion. Also, the IL-1 receptor antagonist, IL1RA, and caspase-1 inhibitor, Ac-YVAD, both inhibited MUC5AC secretion induced by cholesterol crystals. We found that inflammasome activation participates in cholesterol crystal induced mucin secretion and gallstone development.

Dysfunctional Vascular Endothelium as a Driver of Atherosclerosis: Emerging Insights Into Pathogenesis and Treatment

Atherosclerosis, the chronic accumulation of cholesterol-rich plaque within arteries, is associated with a broad spectrum of cardiovascular diseases including myocardial infarction, aortic aneurysm, peripheral vascular disease, and stroke. Atherosclerotic cardiovascular disease remains a leading cause of mortality in high-income countries and recent years have witnessed a notable increase in prevalence within low- and middle-income regions of the world. Considering this prominent and evolving global burden, there is a need to identify the cellular mechanisms that underlie the pathogenesis of atherosclerosis to discover novel therapeutic targets for preventing or mitigating its clinical sequelae. Despite decades of research, we still do not fully understand the complex cell-cell interactions that drive atherosclerosis, but new investigative approaches are rapidly shedding light on these essential mechanisms. The vascular endothelium resides at the interface of systemic circulation and the underlying vessel wall and plays an essential role in governing pathophysiological processes during atherogenesis. In this review, we present emerging evidence that implicates the activated endothelium as a driver of atherosclerosis by directing site-specificity of plaque formation and by promoting plaque development through intracellular processes, which regulate endothelial cell proliferation and turnover, metabolism, permeability, and plasticity. Moreover, we highlight novel mechanisms of intercellular communication by which endothelial cells modulate the activity of key vascular cell populations involved in atherogenesis, and discuss how endothelial cells contribute to resolution biology - a process that is dysregulated in advanced plaques. Finally, we describe important future directions for preclinical atherosclerosis research, including epigenetic and targeted therapies, to limit the progression of atherosclerosis in at-risk or affected patients.

Artemisinin and Procyanidins loaded multifunctional nanocomplexes alleviate atherosclerosis via simultaneously modulating lipid influx and cholesterol efflux

The development of new reagents combining with nanotechnology has become an efficient strategy for improving the immune escaping ability and increasing local drug concentration for natural compounds with low therapy efficiency. In this study, we prepared biomimetic membrane-coated Prussian blue nanoparticles (PB NPs) for the treatment of atherosclerosis, using the function of Artemisinin (ART) and Procyanidins (PC) on the lipid influx and cholesterol efflux of macrophages, two logical steps involved in the plaque progression. In vitro results indicated that the prepared nanocomplexes have significant scavenging effect on ROS and NO, followed by inhibiting NF-κB/NLRP3 pathway, leading to the suppression of lipid influx. Meanwhile, they can notably reduce the uptake and internalization of oxLDL through significantly enhancing AMPK/mTOR/autophagy pathway, accompanied by promoting cholesterol efflux. In vivo study showed that the improved biocompatibility and immune-escape ability of nanocomplexes allowed less drug clearance during the circulation and high drug accumulation in the atherosclerotic plaque of ApoE^-/- mice model. More importantly, the ART and PC co-loaded nanocomplexes showed the high efficacy against atherosclerosis of ApoE^-/- mice model with both 8-week low dosage treatment or 1-week high dosage treatment. These findings indicated that ART and PC co-loaded nanocomplexes was promising for the targeted treatment of atherosclerosis.

Vitexin inhibits APEX1 to counteract the flow-induced endothelial inflammation

Vascular endothelial cells are exposed to shear stresses with disturbed vs. laminar flow patterns, which lead to proinflammatory vs. antiinflammatory phenotypes, respectively. Effective treatment against endothelial inflammation and the consequent atherogenesis requires the identification of new therapeutic molecules and the development of drugs targeting these molecules. Using Connectivity Map, we have identified vitexin, a natural flavonoid, as a compound that evokes the gene-expression changes caused by pulsatile shear, which mimics laminar flow with a clear direction, vs. oscillatory shear (OS), which mimics disturbed flow without a clear direction. Treatment with vitexin suppressed the endothelial inflammation induced by OS or tumor necrosis factor-α. Administration of vitexin to mice subjected to carotid partial ligation blocked the disturbed flow-induced endothelial inflammation and neointimal formation. In hyperlipidemic mice, treatment with vitexin ameliorated atherosclerosis. Using SuperPred, we predicted that apurinic/apyrimidinic endonuclease1 (APEX1) may directly interact with vitexin, and we experimentally verified their physical interactions. OS induced APEX1 nuclear translocation, which was inhibited by vitexin. OS promoted the binding of acetyltransferase p300 to APEX1, leading to its acetylation and nuclear translocation. Functionally, knocking down APEX1 with siRNA reversed the OS-induced proinflammatory phenotype, suggesting that APEX1 promotes inflammation by orchestrating the NF-κB pathway. Animal experiments with the partial ligation model indicated that overexpression of APEX1 negated the action of vitexin against endothelial inflammation, and that endothelial-specific deletion of APEX1 ameliorated atherogenesis. We thus propose targeting APEX1 with vitexin as a potential therapeutic strategy to alleviate atherosclerosis.

Formation and Cellular Impact of Cholesterol Crystals in Health and Disease

Cholesterol crystals (CCs) were first discovered in atherosclerotic plaque tissue in the early 1900 and have since been observed and implicated in many diseases and conditions, including myocardial infarction, abdominal aortic aneurism, kidney disease, ocular diseases, and even central nervous system anomalies. Despite the widespread involvement of CCs in many pathologies, the mechanisms involved in their formation and their role in various diseases are still not fully understood. Current knowledge concerning the formation of CCs, as well as the molecular pathways activated upon cellular exposure to CCs, will be explored in this review. As CC formation is tightly associated with lipid metabolism, the role of cellular lipid homeostasis in the formation of CCs is highlighted, including the role of lysosomes. In addition, cellular pathways and processes known to be affected by CCs are described. In particular, CC-induced activation of the inflammasome and production of reactive oxygen species, along with the role of CCs in complement-mediated inflammation is discussed. Moreover, the clinical manifestation of embolized CCs is described with a focus on renal and skin diseases associated with CC embolism. Lastly, potential therapeutic measures that target either the formation of CCs or their impact on different cell types and tissues are highlighted.

Novel role of xanthine oxidase-dependent H2O2 production in 12/15-lipoxygenase-mediated de novo lipogenesis, triglyceride biosynthesis and weight gain

12/15-lipoxygenase (12/15-LOX) plays an essential role in oxidative conversion of polyunsaturated fatty acids into various bioactive lipid molecules. Although 12/15-LOX's role in the pathophysiology of various human diseases has been well studied, its role in weight gain is controversial and poorly clarified. Here, we demonstrated the role of 12/15-LOX in high-fat diet (HFD)-induced weight gain in a mouse model. We found that 12/15-LOX mediates HFD-induced de novo lipogenesis (DNL), triglyceride (TG) biosynthesis and the transport of TGs from the liver to adipose tissue leading to white adipose tissue (WAT) expansion and weight gain via xanthine oxidase (XO)-dependent production of H₂O₂. 12/15-LOX deficiency leads to cullin2-mediated ubiquitination and degradation of XO, thereby suppressing H₂O₂ production, DNL and TG biosynthesis resulting in reduced WAT expansion and weight gain. These findings infer that manipulation of 12/15-LOX metabolism may manifest a potential therapeutic target for weight gain and obesity.

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12/15-LOX-12(S)-HETE axis via activation of CREB-Egr1 enhances TG biosynthesis.

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12/15-LOX-12(S)-HETE axis via activation of SREBP1c triggers DNL.

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H₂O₂ mediates 12/15-LOX-12(S)-HETE axis-induced DNL and TG biosynthesis.

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12/15-LOX via TG biosynthesis leads to WAT expansion and body weight gain.

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Downstream to 12/15-LOX, H₂O₂-mediates WAT expansion and body weight gain.

Endothelial Dysfunction in Atherosclerotic Cardiovascular Diseases and Beyond: From Mechanism to Pharmacotherapies

The endothelium, a cellular monolayer lining the blood vessel wall, plays a critical role in maintaining multiorgan health and homeostasis. Endothelial functions in health include dynamic maintenance of vascular tone, angiogenesis, hemostasis, and the provision of an antioxidant, anti-inflammatory, and antithrombotic interface. Dysfunction of the vascular endothelium presents with impaired endothelium-dependent vasodilation, heightened oxidative stress, chronic inflammation, leukocyte adhesion and hyperpermeability, and endothelial cell senescence. Recent studies have implicated altered endothelial cell metabolism and endothelial-to-mesenchymal transition as new features of endothelial dysfunction. Endothelial dysfunction is regarded as a hallmark of many diverse human panvascular diseases, including atherosclerosis, hypertension, and diabetes. Endothelial dysfunction has also been implicated in severe coronavirus disease 2019. Many clinically used pharmacotherapies, ranging from traditional lipid-lowering drugs, antihypertensive drugs, and antidiabetic drugs to proprotein convertase subtilisin/kexin type 9 inhibitors and interleukin 1β monoclonal antibodies, counter endothelial dysfunction as part of their clinical benefits. The regulation of endothelial dysfunction by noncoding RNAs has provided novel insights into these newly described regulators of endothelial dysfunction, thus yielding potential new therapeutic approaches. Altogether, a better understanding of the versatile (dys)functions of endothelial cells will not only deepen our comprehension of human diseases but also accelerate effective therapeutic drug discovery. In this review, we provide a timely overview of the multiple layers of endothelial function, describe the consequences and mechanisms of endothelial dysfunction, and identify pathways to effective targeted therapies. SIGNIFICANCE STATEMENT: The endothelium was initially considered to be a semipermeable biomechanical barrier and gatekeeper of vascular health. In recent decades, a deepened understanding of the biological functions of the endothelium has led to its recognition as a ubiquitous tissue regulating vascular tone, cell behavior, innate immunity, cell-cell interactions, and cell metabolism in the vessel wall. Endothelial dysfunction is the hallmark of cardiovascular, metabolic, and emerging infectious diseases. Pharmacotherapies targeting endothelial dysfunction have potential for treatment of cardiovascular and many other diseases.

Neferine suppresses vascular endothelial inflammation by inhibiting the NF-κB signaling pathway

The vascular endothelium, as the interface between the blood and the surrounding tissues, plays a pivotal role in inflammation. Neferine, which was isolated from Lotus Plumule, has many biological roles, such as antifibrotic, antioxidative, anti-inflammatory, and antineoplastic activities. We demonstrated the role of neferine in the inhibition of pro-adhesion and pro-inflammatory responses of endothelial cells in vitro. We found that neferine could significantly inhibit the adhesion of Tohoku Hospital Pediatrics-1 (THP-1) cells to primary human umbilical vein endothelial cells (HUVECs). At the molecular level, neferine could significantly alleviate the interleukin 1β (IL-1β)-induced mRNA and protein expression of intercellular adhesion molecule 1 (ICAM1) and vascular cell adhesion molecule 1 (VCAM1). Our data showed that neferine suppressed nuclear factor-κB (NF-κB) nuclear translocation and inhibited the NF-κB-p65-induced transcriptional activity of ICAM1 and VCAM1. Therefore, we concluded that neferine suppressed the inflammatory response in endothelial cells in vitro, which could be mainly due to inhibition of NF-κB signaling activation. Moreover, we found that neferine alleviated LPS-induced acute inflammation injury in vivo. Thus, neferine may serve as an effective regulator during the pathogenesis of vascular inflammatory diseases.

Resolvin D1 mitigates non-alcoholic steatohepatitis by suppressing the TLR4-MyD88-mediated NF-κB and MAPK pathways and activating the Nrf2 pathway in mice

AIMS

Resolvin D1 (RvD1), a potent endogenous lipid mediator converted from docosahexaenoic acid (DHA), has exert anti-inflammatory and antioxidant effects in many preclinical disease models, but its potential role in non-alcoholic steatohepatitis (NASH) remains elusive. This study was performed to investigate the protective effects and mechanisms of RvD1 in NASH.

MAIN METHODS

In vivo, male C57BL/6 mice were fed an MCD diet for 4 weeks to induce NASH. RvD1 was added in the last 2 weeks of the feeding period. In vitro, lipopolysaccharide (LPS)-activated RAW264.7 macrophages were pretreated with increasing concentrations of RvD1. Serum liver functional markers and hepatic oxidative stress indicators were measured biochemically. Mouse liver tissue sections were stained with hematoxylin-eosin, oil red O, and Masson's trichrome to assess the severity of steatohepatitis, steatosis and fibrosis. The qRT-PCR, immunohistochemistry and Western blotting assays were applied to analyse mechanisms underlying RvD1 protection in NASH.

KEY FINDINGS

In vivo, RvD1 significantly attenuates steatohepatitis in MCD diet-fed mice by modulating key events, including steatosis, inflammation, oxidative stress and fibrosis in the progression of NASH. In vitro, RvD1 also represses LPS-induced inflammation in RAW264.7 cells. These effects may be mainly attributed to RvD1 markedly suppressing excessive inflammatory responses via the inhibition of the TLR4-MyD88-mediated NF-κB and MAPK signalling pathways as well as enhancing antioxidation capacity via the activation of the Nrf2 pathway.

SIGNIFICANCE

These results demonstrate that RvD1 is a promising hepatoprotective agent for the therapy of NASH.

Pathological Roles of Mitochondrial Oxidative Stress and Mitochondrial Dynamics in Cardiac Microvascular Ischemia/Reperfusion Injury

Mitochondria are key regulators of cell fate through controlling ATP generation and releasing pro-apoptotic factors. Cardiac ischemia/reperfusion (I/R) injury to the coronary microcirculation has manifestations ranging in severity from reversible edema to interstitial hemorrhage. A number of mechanisms have been proposed to explain the cardiac microvascular I/R injury including edema, impaired vasomotion, coronary microembolization, and capillary destruction. In contrast to their role in cell types with higher energy demands, mitochondria in endothelial cells primarily function in signaling cellular responses to environmental cues. It is clear that abnormal mitochondrial signatures, including mitochondrial oxidative stress, mitochondrial fission, mitochondrial fusion, and mitophagy, play a substantial role in endothelial cell function. While the pathogenic role of each of these mitochondrial alterations in the endothelial cells I/R injury remains complex, profiling of mitochondrial oxidative stress and mitochondrial dynamics in endothelial cell dysfunction may offer promising potential targets in the search for novel diagnostics and therapeutics in cardiac microvascular I/R injury. The objective of this review is to discuss the role of mitochondrial oxidative stress on cardiac microvascular endothelial cells dysfunction. Mitochondrial dynamics, including mitochondrial fission and fusion, are critically discussed to understand their roles in endothelial cell survival. Finally, mitophagy, as a degradative mechanism for damaged mitochondria, is summarized to figure out its contribution to the progression of microvascular I/R injury.