S100a8/a9 Signaling Causes Mitochondrial Dysfunction and Cardiomyocyte Death in Response to Ischemic/Reperfusion Injury

[Biomarkers in acute coronary syndromes: from the origins to the present]

Acute coronary syndrome remains the leading cause of death in both patients with coronary artery disease and patients with other diseases (such as diabetes mellitus, chronic kidney disease, inflammatory diseases of various etiologies, and others). Early diagnosis of cardiomyocyte damage and necrosis opens up wide opportunities to improve the prognosis of patients with atherosclerotic lesions of the coronary arteries, and also makes it possible to discharge patients without acute cardiovascular pathology from intensive care units with a high degree of probability. The article discusses the evolution of the research and introduction into broad clinical practice of markers of myocardial damage and necrosis, which have largely improved modern clinical practice.

Propofol pretreatment inhibits ferroptosis and alleviates myocardial ischemia-reperfusion injury through the SLC16A13-AMPK-GPX4 pathway

This study investigates the protective effects of propofol on the myocardium by inhibiting the expression of SLC16A13 through in vivo animal experiments, while also exploring its mechanism in ferroptosis to provide new strategies for preventing perioperative myocardial ischemia-reperfusion injury. We randomly divided 30 rats into three groups (n=10 each): sham surgery group, ischemia-reperfusion (I/R) group, and propofol pretreatment group. The results showed that compared with the sham surgery group, the I/R group had a significant decrease in cardiac function and an increase in infarct size. Propofol pretreatment effectively alleviated the damage caused by ischemia-reperfusion (I/R). In the next phase of the study, we administered the PPARα agonist GW7647 to artificially increase the expression of SLC16A13. Fifty rats were randomly divided into five groups (n=10 each), with the GW7647 pretreatment group and propofol+GW7647 pretreatment group added based on the previous three groups. Afterwards, we validated the in vivo results using H9C2 and further explored the mechanism by which propofol inhibits ferroptosis. The study found that L-lactic acid in myocardial tissue of the GW7647 group was further increased compared to the I/R group, and the degree of ferroptosis was aggravated. In addition, upregulation of SLC16A13 significantly inhibited the phosphorylation of AMPK, weakened the protective mechanism of AMPK, and exacerbated cardiac damage. However, propofol pretreatment can effectively inhibit the expression of SLC16A13, maintain normal myocardial cell morphology, and protect cardiac function. These results indicate that propofol inhibits the expression of SLC16A13, alleviates myocardial cell ferroptosis via the AMPK/GPX4 pathway, and reverses damage caused by myocardial ischemia-reperfusion.

Mitochondria-Associated Organelle Crosstalk in Myocardial Ischemia/Reperfusion Injury

Organelle damage is a significant contributor to myocardial ischemia/reperfusion (I/R) injury. This damage often leads to disruption of endoplasmic reticulum protein regulatory programs and dysfunction of mitochondrial energy metabolism. Mitochondria and endoplasmic reticulum are seamlessly connected through the mitochondrial-associated endoplasmic reticulum membrane (MAM), which serves as a crucial site for the exchange of organelles and metabolites. However, there is a lack of reports regarding the communication of information and metabolites between mitochondria and related organelles, which is a crucial factor in triggering myocardial I/R damage. To address this research gap, this review described the role of crosstalk between mitochondria and the correlative organelles such as endoplasmic reticulum, lysosomal and nuclei involved in reperfusion injury of the heart. In summary, this review aims to provide a comprehensive understanding of the crosstalk between organelles in myocardial I/R injury, with the ultimate goal of facilitating the development of targeted therapies based on this knowledge.

CTRP6-mediated cardiac protection in heart failure via the AMPK/SIRT1/PGC-1α signalling pathway

Heart failure (HF) remains a significant global health concern with limited effective treatments available. C1q/TNF-related protein 6 (CTRP6) is a member of the CTRP family analogous to adiponectin and its role in HF pathogenesis remains unclear. Here, we investigated the impact of CTRP6 on HF progression. To mimic heart failure with reduced ejection fraction (HFrEF), we used isoproterenol injection in mice and administered adenovirus vectors expressing CTRP6 (Ad-CTRP6) via tail vein injection. We assessed cardiac function through echocardiography and histology. CTRP6's effects on hypertrophy, fibrosis, apoptosis, oxidative stress and mitochondrial function were analysed. Downstream pathways (phosphorylated AMP-activated protein kinase (p-AMPK), sirtuin 1 (SIRT1) and peroxisome proliferator-activated receptor γ coactivator 1-α (PGC-1α) were studied in heart tissues. In vitro, isoproterenol-stimulated H9c2 cardiomyocytes were treated with CTRP6 to examine viability, apoptosis, F-actin and signalling proteins. Compound C was used to assess AMPK involvement. CTRP6 expression was lower in the plasma of HF patients. In an isoproterenol-induced HFrEF mouse model, adenovirus-mediated overexpression of CTRP6 ameliorated cardiac dysfunction and reduced cardiomyocyte apoptosis, oxidative stress, inflammation and myocardial injury markers. Mechanistically, CTRP6 activation of the AMPK/SIRT1/PGC-1α signalling pathway restored mitochondrial homeostasis, evidenced by reduced mitochondrial reactive oxygen species levels, increased ATP content, and enhanced mitochondrial complex I/III activities in cardiac tissues. In vitro studies using isoproterenol-stimulated H9c2 cardiomyocytes corroborated these findings, demonstrating that CTRP6 upregulation attenuated hypertrophy, apoptosis, oxidative stress and mitochondrial dysfunction. Furthermore, these effects were partially reversed by the AMPK inhibitor Compound C, implicating the involvement of the AMPK pathway in CTRP6-mediated cardioprotection. CTRP6 alleviates HF progression through the AMPK/SIRT1/PGC-1α signalling pathway.

Associations between neutrophil-percentage-to-albumin ratio level and all-cause mortality and cardiovascular disease-cause mortality in general population: evidence from NHANES 1999-2010

Introduction

Chronic inflammation is a recognized independent risk factor for cardiovascular disease (CVD), highlighting the need for reliable inflammatory indicator to predict CVDs. As an inflammatory indicator which has been proved to have predictive value for prognosis of CVDs, neutrophil percentage-to-albumin ratio (NPAR) has obtained increasing attention, but further research is needed to confirm the relationship with mortality in the general population.

Method

This prospective cohort study included 21,317 individuals who participated in the National Health and Nutrition Examination Survey (NHANES) from 1999 to 2010, where baseline characteristics and NPAR level were extracted. Data for CVD and all-cause mortality were acquired by linking the cohort database with the National Death Index through December 31, 2019. We employed restricted cubic spline analyses to examine the nonlinear association. Weighted Kaplan-Meier curves with log-rank tests were conducted to access cumulative survival differences across different NPAR results. Multivariable Cox proportional hazards regression models were used to compute hazard ratios and 95% CIs. Receiver Operating Characteristic (ROC) curves were used to compare predictive value of NPAR with systemic immune inflammation index (SII) and neutrophils percent.

Results

In this cohort study, during 270,014 person-years of follow-up, 4,074 all-cause deaths and 1,116 CVD-cause deaths were documented. NPAR levels exhibited significant nonlinear associations with both CVD-cause (P = 0.018 for nonlinearity) and all-cause mortality (P < 0.001 for nonlinearity). Participants in the highest NPAR tertile had a significantly increased risk of all-cause mortality (HR: 1.46, 95% CI: 1.33-1.61) and CVD-cause mortality (HR: 1.54, 95% CI: 1.32-1.80) compared to those in the lowest tertile in the fully adjusted model, while no association was detected for individuals in the middle tertile. Further ROC analysis confirmed that NPAR had higher predictive value than neutrophil percent segment and SII.

Conclusions

Elevated NPAR level was significantly associated with an increased risk of all-cause and CVD-cause mortality in general population. The high predictive value of NPAR, combined with the easy-to-calculate property, suggests that its potential as a novel inflammatory indicator is worthy of further investigation.

Circulating biomarkers of myocardial remodelling: current developments and clinical applications

Myocardial remodelling, entailing cellular and molecular changes in the different components of the cardiac tissue in response to damage, underlies the morphological and structural changes leading to cardiac remodelling, which in turn contributes to cardiac dysfunction and disease progression. Since cardiac tissue is not available for histomolecular diagnosis, surrogate markers are needed for evaluating myocardial remodelling as part of the clinical management of patients with cardiac disease. In this setting, circulating biomarkers, a component of the liquid biopsy, provide a promising approach for the fast, affordable and scalable screening of large numbers of patients, allowing the detection of different pathological features related to myocardial remodelling, aiding in risk stratification and therapy monitoring. However, despite the advances in the field and the identification of numerous potential candidates, their implementation in clinical practice beyond natriuretic peptides and troponins is mostly lacking. In this review, we will discuss some biomarkers related to alterations in the main cardiac tissue compartments (cardiomyocytes, extracellular matrix, endothelium and immune cells) which have shown potential for the assessment of cardiovascular risk, cardiac remodelling and therapy effects. The hurdles and challenges for their translation into clinical practice will also be addressed.

Engineered Macrophage Membrane-Coated S100A9-siRNA for Ameliorating Myocardial Ischemia-Reperfusion Injury

Despite the widespread adoption of emergency coronary reperfusion therapy, reperfusion-induced myocardial injury remains a challenging issue in clinical practice. Following myocardial reperfusion, S100A8/A9 molecules are considered pivotal in initiating and regulating tissue inflammatory damage. Effectively reducing the S100A8/A9 level in ischemic myocardial tissue holds significant therapeutic value in salvaging damaged myocardium. In this study, HA (hemagglutinin)- and RAGE (receptor for advanced glycation end products)- comodified macrophage membrane-coated siRNA nanoparticles (MMM/RNA NPs) with siRNA targeting S100A9 (S100A9-siRNA) are successfully prepared. This nanocarrier system is able to target effectively the injured myocardium in an inflammatory environment while evading digestive damage by lysosomes. In vivo, migration of MMM/RNA NPs to myocardial injury lesions is confirmed in a myocardial ischemia-reperfusion injury (MIRI) mouse model. Intravenous injection of MMM/RNA NPs significantly reduced S100A9 levels in serum and myocardial tissues, further decreasing myocardial infarction area and improving cardiac function. Targeted reduction of S100A8/A9 by genetically modified macrophage membrane-coated nanoparticles may represent a new therapeutic intervention for MIRI.

Unraveling the Mechanisms of S100A8/A9 in Myocardial Injury and Dysfunction

S100A8 and S100A9, which are prominent members of the calcium-binding protein S100 family and recognized as calprotectin, form a robust heterodimer known as S100A8/A9, crucial for the manifestation of their diverse biological effects. Currently, there is a consensus that S100A8/A9 holds promise as a biomarker for cardiovascular diseases (CVDs), exerting an influence on cardiomyocytes or the cardiovascular system through multifaceted mechanisms that contribute to myocardial injury or dysfunction. In particular, the dualistic nature of S100A8/A9, which functions as both an inflammatory mediator and an anti-inflammatory agent, has garnered significantly increasing attention. This comprehensive review explores the intricate mechanisms through which S100A8/A9 operates in cardiovascular diseases, encompassing its bidirectional regulatory role in inflammation, the initiation of mitochondrial dysfunction, the dual modulation of myocardial fibrosis progression, and apoptosis and autophagy. The objective is to provide new information on and strategies for the clinical diagnosis and treatment of cardiovascular diseases in the future.

Neutrophil-secreted S100A8/A9 participates in fatty liver injury and fibrosis by promoting myofibroblast migration

Fatty liver, which is induced by abnormal lipid metabolism, is one of the most common causes of chronic liver disease globally and causes liver fibrosis. During this process, bone marrow-derived mesenchymal stromal cells (BMSCs) and hepatic stellate cells (HSCs) migrate toward the injured liver and participate in fibrogenesis by transdifferentiating into myofibroblasts. S100A8/A9 is a powerful inducer of cell migration and is involved in liver injury. But there are few reports about the effects of S100A8/A9 on BMSC/HSC migration. In the current study, we found that S100A8/A9 expression was increased during fatty liver injury/fibrogenesis. Moreover, S100A8/A9 expression had a positive correlation with fibrosis marker gene expressions in the injured liver. S100A8/A9 was mainly produced by neutrophils in the fibrotic liver. In vitro, neutrophil-secreted S100A8/A9 promoted BMSC/HSC migration via remodeling of microfilaments. Using specific siRNA and inhibitor, we proved that S100A8/A9-induced BMSC/HSC migration is dependent on TLR4/Rho GTPases signaling. Moreover, S100A8/A9 knock-down alleviated liver injury and fibrogenesis in vivo, while injection of S100A9 neutralizing antibody performed similar roles. We proved that S100A8/A9 was involved in liver injury and fibrogenesis via inducing BMSC/HSC migration. Our research reveals a new mechanism underlying BMSC/HSC migration in liver fibrosis and suggests S100A8/A9 as a potential therapeutic target of liver fibrosis. KEY MESSAGES: S100A8/A9 is secreted by neutrophils and increased in fatty liver injury. Neutrophil-secreted S100A8/A9 is a mediator of BMSC/HSC migration in vitro. S100A8/A9-induced BMSC/HSC migration is dependent on TLR4/Rho GTPases signaling. S100A8/A9 blockade alleviates liver injury and fibrogenesis in vivo.

The Role of Alarmins in the Pathogenesis of Atherosclerosis and Myocardial Infarction

Atherosclerosis is a condition that is associated with lipid accumulation in the arterial intima. Consequently, the enlarging lesion, which is also known as an atherosclerotic plaque, may close the blood vessel lumen, thus leading to organ ischaemia. Furthermore, the plaque may rupture and initiate the formation of a thrombus, which can cause acute ischaemia. Atherosclerosis is a background pathological condition that can eventually lead to major cardiovascular diseases such as acute coronary syndrome or ischaemic stroke. The disorder is associated with an altered profile of alarmins, stress response molecules that are secreted due to cell injury or death and that induce inflammatory responses. High-mobility group box 1 (HMGB1), S100 proteins, interleukin-33, and heat shock proteins (HSPs) also affect the behaviour of endothelial cells and vascular smooth muscle cells (VSMCs). Thus, alarmins control the inflammatory responses of endothelial cells and proliferation of VSMCs, two important processes implicated in the pathogenesis of atherosclerosis. In this review, we will discuss the role of alarmins in the pathophysiology of atherosclerosis and myocardial infarction.

Extracellular vesicles: opening up a new perspective for the diagnosis and treatment of mitochondrial dysfunction

Mitochondria are crucial organelles responsible for energy generation in eukaryotic cells. Oxidative stress, calcium disorders, and mitochondrial DNA abnormalities can all cause mitochondrial dysfunction. It is now well documented that mitochondrial dysfunction significantly contributes to the pathogenesis of numerous illnesses. Hence, it is vital to investigate innovative treatment methods targeting mitochondrial dysfunction. Extracellular vesicles (EVs) are cell-derived nanovesicles that serve as intercellular messengers and are classified into small EVs (sEVs, < 200 nm) and large EVs (lEVs, > 200 nm) based on their sizes. It is worth noting that certain subtypes of EVs are rich in mitochondrial components (even structurally intact mitochondria) and possess the ability to transfer them or other contents including proteins and nucleic acids to recipient cells to modulate their mitochondrial function. Specifically, EVs can modulate target cell mitochondrial homeostasis as well as mitochondria-controlled apoptosis and ROS generation by delivering relevant substances. In addition, the artificial modification of EVs as delivery carriers for therapeutic goods targeting mitochondria is also a current research hotspot. In this article, we will focus on the ability of EVs to modulate the mitochondrial function of target cells, aiming to offer novel perspectives on therapeutic approaches for diverse conditions linked to mitochondrial dysfunction.

S100a8/A9 proteins: critical regulators of inflammation in cardiovascular diseases

Neutrophil hyperexpression is recognized as a key prognostic factor for inflammation and is closely related to the emergence of a wide range of cardiovascular disorders. In recent years, S100 calcium binding protein A8/A9 (S100A8/A9) derived from neutrophils has attracted increasing attention as an important warning protein for cardiovascular disease. This article evaluates the utility of S100A8/A9 protein as a biomarker and therapeutic target for diagnosing cardiovascular diseases, considering its structural features, fundamental biological properties, and its multifaceted influence on cardiovascular conditions including atherosclerosis, myocardial infarction, myocardial ischemia/reperfusion injury, and heart failure.

S100A9 Induces Macrophage M2 Polarization and Immunomodulatory Role in the Lesion Site After Spinal Cord Injury in Rats

Immune response is pivotal in the secondary injury of spinal cord injury (SCI). Polarization of macrophages (MΦ) influences the immune response in the secondary injury, which is regulated by several immune-related proteins. M2Φ plays the immunomodulatory role in the central nervous system. This study used bioinformatic analysis and machine algorithms to screen hub immune-related proteins after SCI and experimentally investigate the role of the target protein in the M2Φ polarization and immunomodulation in rats and in vitro after SCI. We downloaded GSE151371 and GSE45006, hub immune-related genes were screened using machine learning algorithms, and the expression of S100A9 was verified by datasets. Allen's weight-drop injury SCI model in Sprague-Dawley rat and bone marrow-derived rat MΦ with myelin debris model were used to study the effects of S100A9 on M2Φ polarization and immunomodulation at the lesion site and in vitro. Bioinformatic analysis showed that S100A9 acts as a hub immune-related gene in the SCI patients and rats. S100A9 increased at the lesion site in SCI rats, and its inhibition reduced CD206 and ARG-1 expression. Exogenous S100A9 promoted CD206 and ARG-1 expression in MΦ. S100A9 also increased the expression of PD-L1 and decreased MHC II at the lesion site in SCI rats and MΦ with myelin debris, and enhanced mitochondrial activity in rat MΦ with myelin debris. In conclusion, S100A9 is an indispensable factor in the immune process in secondary injury following SCI.

ITFG2, an immune-modulatory protein, targets ATP 5b to maintain mitochondrial function in myocardial infarction

ITFG2, as an immune-modulatory intracellular protein that modulate the fate of B cells and negatively regulates mTORC1 signaling. ITFG2 is highly expressed in the heart, but its pathophysiological function in heart disease is unclear. In this study, we found that in MI mice, overexpression of ITFG2 via an AAV9 vector significantly reduced the infarct size and ameliorated cardiac function. Knockdown of endogenous ITFG2 by shRNA partially aggravated ischemia-induced cardiac dysfunction. In cardiac-specific ITFG2 transgenic (TG) mice, myocardial infarction size was smaller, eject fraction (EF) and fractional shortening (FS) was higher compared to those in wild-type (WT) mice, suggesting ITFG2 reversed cardiac dysfunction induced by MI. In hypoxic neonatal cardiomyocytes (NMCMs), overexpression of ITFG2 maintained mitochondrial function by increasing intracellular ATP production, reducing ROS levels, and preserving the mitochondrial membrane potential (MMP). Overexpression of ITFG2 reversed the mitochondrial respiratory dysfunction in NMCMs induced by hypoxia. Knockdown of endogenous ITFG2 by siRNA did the opposite. Mechanism, ITFG2 formed a complex with NEDD4-2 and ATP 5b and inhibited the binding of NEDD4-2 with ATP 5b leading to the reduction ubiquitination of ATP 5b. Our findings reveal a previously unknown ability of ITFG2 to protect the heart against ischemic injury by interacting with ATP 5b and thereby regulating mitochondrial function. ITFG2 has promise as a novel strategy for the clinical management of MI.

Advances in the study of S100A9 in cardiovascular diseases

Cardiovascular disease (CVD) is a group of diseases that primarily affect the heart or blood vessels, with high disability and mortality rates, posing a serious threat to human health. The causative factors, pathogenesis, and characteristics of common CVD differ, but they all involve common pathological processes such as inflammation, oxidative stress, and fibrosis. S100A9 belongs to the S100 family of calcium-binding proteins, which are mainly secreted by myeloid cells and bind to the Toll-like receptor 4 and receptor for advanced glycation end products and is involved in regulating pathological processes such as inflammatory response, fibrosis, vascular calcification, and endothelial barrier function in CVD. The latest research has found that S100A9 is a key biomarker for diagnosing and predicting various CVD. Therefore, this article reviews the latest research progress on the diagnostic and predictive, and therapeutic value of S100A9 in inflammatory-related CVD such as atherosclerosis, myocardial infarction, and arterial aneurysm and summarizes its molecular mechanisms in the progression of CVD, aiming to explore new predictive methods and to identify potential intervention targets for CVD in clinical practice.

Formyl peptide receptor 1 mitigates colon inflammation and maintains mucosal homeostasis through the inhibition of CREB-C/EBPβ-S100a8 signaling

Excessive inflammatory responses are the main characteristic of ulcerative colitis (UC). Activation of formyl peptide receptor 1 (FPR1) has been found to promote the proliferation and migration of epithelial cells, but its role and therapeutic potential in UC remain unclear. This study observed an increased expression of FPR1 in a mouse model of colitis. Interestingly, FPR1 deficiency exacerbated UC and increased the secretion of the proinflammatory mediator from immune cells (e.g. macrophages), S100a8, a member of the damage-associated molecular patterns. Notably, the administration of the FPR agonist Cmpd43 ameliorated colon injury in a preclinical mice model of UC, likely via inhibiting phosphorylation of cyclic adenosine monophosphate-response element-binding protein and expression of CCAAT/enhancer-binding protein β, which in turn suppressed the secretion of S100a8. In conclusion, these findings discovered a novel role of FPR1 in the development of colitis and will facilitate the development of FPR1-based pharmacotherapy to treat UC.

Mitochondrial complex-1 as a therapeutic target for cardiac diseases

Mitochondrial dysfunction is critical for the development and progression of cardiovascular diseases (CVDs). Complex-1 (CI) is an essential component of the mitochondrial electron transport chain that participates in oxidative phosphorylation and energy production. CI is the largest multisubunit complex (~ 1 Mda) and comprises 45 protein subunits encoded by seven mt-DNA genes and 38 nuclear genes. These subunits function as the enzyme nicotinamide adenine dinucleotide  hydrogen (NADH): ubiquinone oxidoreductase. CI dysregulation has been implicated in various CVDs, including heart failure, ischemic heart disease, pressure overload, hypertrophy, and cardiomyopathy. Several studies demonstrated that impaired CI function contributes to increased oxidative stress, altered calcium homeostasis, and mitochondrial DNA damage in cardiac cells, leading to cardiomyocyte dysfunction and apoptosis. CI dysfunction has been associated with endothelial dysfunction, inflammation, and vascular remodeling, critical processes in developing atherosclerosis and hypertension. Although CI is crucial in physiological and pathological conditions, no potential therapeutics targeting CI are available to treat CVDs. We believe that a lack of understanding of CI's precise mechanisms and contributions to CVDs limits the development of therapeutic strategies. In this review, we comprehensively analyze the role of CI in cardiovascular health and disease to shed light on its potential therapeutic target role in CVDs.

Short-term S100A8/A9 Blockade Promotes Cardiac Neovascularization after Myocardial Infarction

Acute-phase inhibition of the pro-inflammatory alarmin S100A8/A9 improves cardiac function post-myocardial infarction (MI), but the mechanisms underlying the long-term benefits of this short-term treatment remain to be elucidated. Here, we assessed the effects of S100A8/A9 blockade with the small-molecule inhibitor ABR-238901 on myocardial neovascularization in mice with induced MI. The treatment significantly reduced S100A9 and increased neovascularization in the myocardium, assessed by CD31 staining. Proteomic analysis by mass-spectrometry showed strong myocardial upregulation of the pro-angiogenic proteins filamin A (~ 10-fold) and reticulon 4 (~ 5-fold), and downregulation of the anti-angiogenic proteins Ras homolog gene family member A (RhoA, ~ 4.7-fold), neutrophilic granule protein (Ngp, ~ 4.0-fold), and cathelicidin antimicrobial peptide (Camp, ~ 4.4-fold) versus controls. In-vitro, ABR-238901 protected against apoptosis induced by recombinant human S100A8/A9 in human umbilical vein endothelial cells (HUVECs). In conclusion, S100A8/A9 blockade promotes post-MI myocardial neovascularization by favorably modulating pro-angiogenic proteins in the myocardium and by inhibiting endothelial cell apoptosis.

S100A9 as a Key Myocardial Injury Factor Interacting with ATP5 Exacerbates Mitochondrial Dysfunction and Oxidative Stress in Sepsis-Induced Cardiomyopathy

Purpose

Sepsis-induced cardiomyopathy (SICM) is a prevalent cardiac dysfunction caused by sepsis. Mitochondrial dysfunction is a crucial pathogenic factor associated with adverse cardiovascular adverse events; however, research on SICM remains insufficient.

Methods

To investigate the factors contributing to the pathological progression of SICM, we performed a comprehensive analysis of transcriptomic data from the GEO database using bioinformatics and machine learning techniques. CRISPR-Cas9 S100A9 knockout mice and primary cardiomyocytes were exposed to lipopolysaccharide to simulate SICM. Transcriptome analysis and mass spectrometry of primary cardiomyocytes were used to determine the potential pathogenic mechanisms of S100A9. The mitochondrial ultrastructure and mitochondrial membrane potential (MMP) were detected using transmission electron microscopy and flow cytometry, respectively. Pink1/Parkin and Drp1 proteins were detected using Western blotting to evaluate mitochondrial autophagy and division. The mtDNA and mRNA levels of mitochondrial transcription factors and synthases were evaluated using real-time polymerase chain reaction.

Results

Bioinformatics analysis identified 12 common differentially expressed genes, including SERPINA3N, LCN2, MS4A6D, LRG1, OSMR, SOCS3, FCGR2b, S100A9, S100A8, CASP4, ABCA8A, and NFKBIZ. Significant S100A9 upregulation was closely associated with myocardial injury exacerbation and cardiac function deterioration. GSEA revealed that myocardial contractile function, oxidative stress, and mitochondrial function were significantly affected by S100A9. Knocking out S100A9 alleviates the inflammatory response and mitochondrial dysfunction. The interaction of S100A9 with ATP5 enhanced mitochondrial division and autophagy, inhibited MMP and ATP synthesis, and induced oxidative stress, which are related to the Nlrp3-Nfkb-Caspase1 and Drp1-Pink1-Parkin signaling pathways. The expression of mitochondrial transcription factors (TFAM and TFBM) and ATP synthetases (ATP6 and ATP8, as well as COX1, COX2, and COX3) was further suppressed by S100A9 in SICM. Targeted S100A9 inhibition by paquinimod partially reversed myocardial mitochondrial dysfunction and oxidative stress.

Conclusion

The interaction of S100A9 with ATP5 exacerbates myocardial damage in sepsis by inducing mitochondrial dysfunction and oxidative stress.

Circulating Levels of Calprotectin as a Biomarker in Patients With Coronary Artery Disease: A Systematic Review and Meta-Analysis

BACKGROUND

Calprotectin, also known as MRP8/14, is generated by immune cells and is altered in several inflammatory diseases. Studies have assessed their levels in patients with coronary artery disease (CAD) and its subtypes (stable CAD and acute coronary syndrome [ACS]). Herein, we aimed to systematically investigate these associations through a systematic review and meta-analysis.

METHODS

A systematic search was conducted in four online databases, including PubMed, Scopus, Embase, and the Web of Science. Relevant studies were retrieved, screened, and extracted. Random-effect meta-analysis was performed for the calculation of standardized mean difference (SMD) and 95% confidence interval (CI). Blood calprotectin levels were compared between CAD patients and controls, as well as CAD subtypes.

RESULTS

A total of 20 studies were included in the systematic review and meta-analysis, comprising 3300 CAD patients and 1230 controls. Patients with CAD had significantly higher calprotectin levels (SMD 0.81, 95% CI 0.32-1.30, p < 0.01). Similarly, patients with ACS were reported to have higher levels compared to those with stable CAD. However, there was no significant difference in terms of blood calprotectin levels between stable CAD cases and healthy controls. Finally, studies have shown that calprotectin could be used as a diagnostic biomarker of CAD while also predicting major adverse events and mortality in these patients.

CONCLUSION

Based on our findings, calprotectin, as an inflammatory marker, could be used as a possible biomarker for patients with CAD and ACS. These suggest the possibility of pathophysiological pathways for this involvement and warrant further research on these associations as well as their clinical utility.

S100A8/A9hi neutrophils induce mitochondrial dysfunction and PANoptosis in endothelial cells via mitochondrial complex I deficiency during sepsis

S100a8/a9, largely released by polymorphonuclear neutrophils (PMNs), belongs to the S100 family of calcium-binding proteins and plays a role in a variety of inflammatory diseases. Although S100a8/a9 has been reported to trigger endothelial cell apoptosis, the mechanisms of S100a8/a9-induced endothelial dysfunction during sepsis require in-depth research. We demonstrate that high expression levels of S100a8/a9 suppress Ndufa3 expression in mitochondrial complex I via downregulation of Nrf1 expression. Mitochondrial complex I deficiency contributes to NAD+-dependent Sirt1 suppression, which induces mitochondrial disorders, including excessive fission and blocked mitophagy, and mtDNA released from damaged mitochondria ultimately activates ZBP1-mediated PANoptosis in endothelial cells. Moreover, based on comprehensive scRNA-seq and bulk RNA-seq analyses, S100A8/A9hi neutrophils are closely associated with the circulating endothelial cell count (a useful marker of endothelial damage), and S100A8 is an independent risk factor for poor prognosis in sepsis patients.

A Whole-Course-Repair System Based on Stimulus-Responsive Multifunctional Hydrogels for Myocardial Tissue Regeneration

Myocardial infarction (MI) has emerged as the predominant cause of cardiovascular morbidity globally. The pathogenesis of MI unfolds as a progressive process encompassing three pivotal phases: inflammation, proliferation, and remodeling. Smart stimulus-responsive hydrogels have garnered considerable attention for their capacity to deliver therapeutic drugs precisely and controllably at the MI site. Here, a smart stimulus-responsive hydrogel with a dual-crosslinked network structure is designed, which enables the precise and controlled release of therapeutic drugs in different pathological stages for the treatment of MI. The hydrogel can rapidly release curcumin (Cur) in the inflammatory phase of MI to exert anti-apoptotic/anti-inflammatory effects. Recombinant humanized collagen type III (rhCol III) is loaded in the hydrogel and released as the hydrogel swelled/degraded during the proliferative phase to promote neovascularization. RepSox (a selective TGF-β inhibitor) releases from Pluronic F-127 grafted with aldehyde nanoparticles (PF127-CHO@RepSox NPs) in the remodeling phase to against fibrosis. The results in vitro and in vivo suggest that the hydrogel improves cardiac function and alleviates cardiac remodeling by suppressing inflammation and apoptosis, promoting neovascularization, and inhibiting myocardial fibrosis. A whole-course-repair system, leveraging stimulus-responsive multifunctional hydrogels, demonstrates notable effectiveness in enhancing post-MI cardiac function and facilitating the restoration of damaged myocardial tissue.

Blocking the TRAIL-DR5 Pathway Reduces Cardiac Ischemia-Reperfusion Injury by Decreasing Neutrophil Infiltration and Neutrophil Extracellular Traps Formation

PURPOSE

Acute myocardial infarction (AMI) is a leading cause of mortality. Neutrophils penetrate injured heart tissue during AMI or ischemia-reperfusion (I/R) injury and produce inflammatory factors, chemokines, and extracellular traps that exacerbate heart injury. Inhibition of the TRAIL-DR5 pathway has been demonstrated to alleviate cardiac ischemia-reperfusion injury in a leukocyte-dependent manner. However, it remains unknown whether TRAIL-DR5 signaling is involved in regulating neutrophil extracellular traps (NETs) release.

METHODS

This study used various models to examine the effects of activating the TRAIL-DR5 pathway with soluble mouse TRAIL protein and inhibiting the TRAIL-DR5 signaling pathway using DR5 knockout mice or mDR5-Fc fusion protein on NETs formation and cardiac injury. The models used included a co-culture model involving bone marrow-derived neutrophils and primary cardiomyocytes and a model of myocardial I/R in mice.

RESULTS

NETs formation is suppressed by TRAIL-DR5 signaling pathway inhibition, which can lessen cardiac I/R injury. This intervention reduces the release of adhesion molecules and chemokines, resulting in decreased neutrophil infiltration and inhibiting NETs production by downregulating PAD4 in neutrophils.

CONCLUSION

This work clarifies how the TRAIL-DR5 signaling pathway regulates the neutrophil response during myocardial I/R damage, thereby providing a scientific basis for therapeutic intervention targeting the TRAIL-DR5 signaling pathway in myocardial infarction.

Mitochondrial transplantation confers protection against the effects of ischemic stroke by repressing microglial pyroptosis and promoting neurogenesis

Transferring healthy and functional mitochondria to the lateral ventricles confers neuroprotection in a rat model of ischemia-reperfusion injury. Autologous mitochondrial transplantation is also beneficial in pediatric patients with cardiac ischemia-reperfusion injury. Thus, transplantation of functional exogenous mitochondria may be a promising therapeutic approach for ischemic disease. To explore the neuroprotective effect of mitochondria transplantation and determine the underlying mechanism in ischemic stroke, in this study we established a photo-thrombosis-induced mouse model of focal ischemia and administered freshly isolated mitochondria via the tail vein or to the injury site (in situ ). Animal behavior tests, immunofluorescence staining, 2,3,5-triphenyltetrazolium chloride (TTC) staining, mRNA-seq, and western blotting were used to assess mouse anxiety and memory, cortical infarct area, pyroptosis, and neurogenesis, respectively. Using bioinformatics analysis, western blotting, co-immunoprecipitation, and mass spectroscopy, we identified S100 calcium binding protein A9 (S100A9) as a potential regulator of mitochondrial function and determined its possible interacting proteins. Interactions between exogenous and endogenous mitochondria, as well as the effect of exogenous mitochondria on recipient microglia, were assessed in vitro . Our data showed that: (1) mitochondrial transplantation markedly reduced mortality and improved emotional and cognitive function, as well as reducing infarct area, inhibiting pyroptosis, and promoting cortical neurogenesis; (2) microglial expression of S100A9 was markedly increased by ischemic injury and regulated mitochondrial function; (3) in vitro , exogenous mitochondria enhanced mitochondrial function, reduced redox stress, and regulated microglial polarization and pyroptosis by fusing with endogenous mitochondria; and (4) S100A9 promoted internalization of exogenous mitochondria by the microglia, thereby amplifying their pro-proliferation and anti-inflammatory effects. Taken together, our findings show that mitochondrial transplantation protects against the deleterious effects of ischemic stroke by suppressing pyroptosis and promoting neurogenesis, and that S100A9 plays a vital role in promoting internalization of exogenous mitochondria.

Human Umbilical Cord Mesenchymal Stem Cells-derived Exosomal lncRNA FAM99B Represses Hepatocellular Carcinoma Cell Malignancy

Human umbilical cord mesenchymal stem cell (hucMSC)-derived exosomes (Exo) have been frequently investigated for disease control. This study was designed to explore the effects of hucMSC-Exo carrying lncRNA family with sequence similarity 99-member B (Exo-lncRNA FAM99B) on hepatocellular carcinoma (HCC) cell behaviour. The expression of lncRNA FAM99B in HCC cells was measured by reverse-transcription quantitative polymerase chain reaction. Protein levels of exosomal markers were quantified using western blotting. Flow cytometry analyses were performed to detect surface markers of hucMSCs and to measure the effects of Exo-lncRNA FAM99B on HCC cell cycle progression and cell apoptosis. Nanoparticle tracking analysis was used to measure the particle size of the exosomes. Additionally, cell viability was evaluated using methyl thiazolyl tetrazolium assays, and Transwell assays were performed to measure cell migration and invasion. Xenograft tumor models were established to explore the role of Exo-lncRNA FAM99B in vivo. Experimental results revealed that lncRNA FAM99B was downregulated in HCC cell lines, and low level of FAM99B is associated with poor survival rates in patients with HCC according to bioinformatics analysis. HucMSCs were identified in a good morphology with positively expressed CD105, CD29, and CD44 as well as negatively expressed CD31, CD14, and HLA-DR. High protein levels of exosomal markers (Alix, CD63 and TSG101) identified the existence of HucMSC-Exo. Importantly, the hucMSCs-Exo could enter HCC cells and exerted a suppressive effect on malignant cell activities. Moreover, overexpression of Exo-lncRNA FAM99B enhanced cell cycle arrest and cell apoptosis while suppressing cell viability, migration, and invasion in HCC. Exo-siRNA-FAM99B exerted the opposite effects on HCC cell process. In vivo experiments verified that Exo-lncRNA FAM99B inhibited tumorigenesis in HCC. In summary, lncRNA FAM99B derived from hucMSC-Exo inhibited malignant cellular phenotypes and tumorigenesis in HCC, which might provide a novel therapeutic strategy for HCC treatment.

Identification and validation of lipid metabolism-related key genes as novel biomarkers in acute myocardial infarction and pan-cancer analysis

BACKGROUND

Acute myocardial infarction (AMI) is associated with high morbidity and mortality, and is associated with abnormal lipid metabolism. We identified lipid metabolism related genes as biomarkers of AMI, and explored their mechanisms of action.

METHODS

Microarray datasets were downloaded from the GEO database and lipid metabolism related genes were obtained from Molecular Signatures Database. WGCNA was performed to identify key genes. We evaluated differential expression and performed ROC and ELISA analyses. We also explored the mechanism of AMI mediated by key genes using gene enrichment analysis. Finally, immune infiltration and pan-cancer analyses were performed for the identified key genes.

RESULTS

TRL2, S100A9, and HCK were identified as key genes related to lipid metabolism in AMI. Internal and external validation (including ELISA) showed that these were good biomarkers of AMI. In addition, the results of gene enrichment analysis showed that the key genes were enriched in inflammatory response, immune system process, and tumor-related pathways. Finally, the results of immune infiltration showed that key genes were concentrated in neutrophils and macrophages, and pan-cancer analysis showed that the key genes were highly expressed in most tumors and were associated with poor prognosis.

CONCLUSIONS

TLR2, S100A9, and HCK were identified as lipid metabolism related novel diagnostic biomarkers of AMI. In addition, AMI and tumors may be related through the inflammatory immune response.

Hofmann Bowman M, Yan L. S100a8/9 (S100 Calcium Binding Protein a8/9) Promotes Cardiac Hypertrophy Via Upregulation of FGF23 (Fibroblast Growth Factor 23) in Mice

BACKGROUND

S100a8/9 (S100 calcium binding protein a8/9) belongs to the S100 family and has gained a lot of interest as a critical regulator of inflammatory response. Our previous study found that S100a8/9 homolog promoted aortic valve sclerosis in mice with chronic kidney disease. However, the role of S100a8/9 in pressure overload-induced cardiac hypertrophy remains unclear. The present study was to explore the role of S100a8/9 in cardiac hypertrophy.

METHODS AND RESULTS

Cardiomyocyte-specific S100a9 loss or gain of function was achieved using an adeno-associated virus system, and the model of cardiac hypertrophy was established by aortic banding-induced pressure overload. The results indicate that S100a8/9 expression was increased in response to pressure overload. S100a9 deficiency alleviated pressure overload-induced hypertrophic response, whereas S100a9 overexpression accelerated cardiac hypertrophy. S100a9-overexpressed mice showed increased FGF23 (fibroblast growth factor 23) expression in the hearts after exposure to pressure overload, which activated calcineurin/NFAT (nuclear factor of activated T cells) signaling in cardiac myocytes and thus promoted hypertrophic response. A specific antibody that blocks FGFR4 (FGF receptor 4) largely abolished the prohypertrophic response of S100a9 in mice.

CONCLUSIONS

In conclusion, S100a8/9 promoted the development of cardiac hypertrophy in mice. Targeting S100a8/9 may be a promising therapeutic approach to treat cardiac hypertrophy.

Semaglutide ameliorates obesity-induced cardiac inflammation and oxidative stress mediated via reduction of neutrophil Cxcl2, S100a8, and S100a9 expression

Obesity, which is driven by inflammation and oxidative stress, is a risk factor for cardiovascular disease. Semaglutide, a glucagon-like peptide-1 receptor agonist, is an antidiabetic drug with major effects on weight loss. In this study, single-cell transcriptomics was used to examine non-cardiomyocytes to uncover the mechanism of obesity-induced myocardial damage and the cardioprotective impact of semaglutide. We constructed obese mouse models and measured Tumor Necrosis Factor-α (TNF-α), Interleukin-6 (IL-6), Reactive Oxygen Species (ROS), and Malonic dialdehyde (MDA) levels in serum and heart tissue to determine the levels of inflammation and oxidative stress in obesity and the effect of semaglutide on these levels. Then, utilizing single-cell transcriptomes to screen for key cell populations and differentially expressed genes (DEGs), we assessed the effects of obesity and semaglutide on non-cardiac cells. Finally, a DEG localization analysis was performed to explore DEGs as well as cell types associated with inflammation and oxidative stress. Semaglutide reduced increased TNF-α, IL-6, ROS, and MDA levels in serum and cardiac tissues in obese mouse. Several genes are closely associated with inflammation and oxidative stress. Chemokine (C-X-C motif) ligand 2 (Cxcl2), S100 calcium binding protein A8 (S100a8), and S100 calcium binding protein A9 (S100a9), which were elevated in obesity but decreased following semaglutide treatment, were also expressed particularly in neutrophils. Finally, by decreasing neutrophil Cxcl2, S100a8, and S100a9 expressions, semaglutide may help to reduce cardiac inflammation and oxidative stress. Semaglutide significantly reduced body weight in obese mice as well as exerted anti-inflammatory and antioxidant effects possibly by inhibiting the expression of S100a8, S100a9, and Cxcl2 in neutrophils. These discoveries are expected to reveal new molecular mechanisms underlying obesity-related heart damage and semaglutide's cardioprotective properties.

FGF4 protects the liver from immune-mediated injury by activating CaMKKβ-PINK1 signal pathway to inhibit hepatocellular apoptosis

Immune-mediated liver injury (ILI) is a condition where an aberrant immune response due to various triggers causes the destruction of hepatocytes. Fibroblast growth factor 4 (FGF4) was recently identified as a hepatoprotective cytokine; however, its role in ILI remains unclear. In patients with autoimmune hepatitis (type of ILI) and mouse models of concanavalin A (ConA)- or S-100-induced ILI, we observed a biphasic pattern in hepatic FGF4 expression, characterized by an initial increase followed by a return to basal levels. Hepatic FGF4 deficiency activated the mitochondria-associated intrinsic apoptotic pathway, aggravating hepatocellular apoptosis. This led to intrahepatic immune hyper-reactivity, inflammation accentuation, and subsequent liver injury in both ILI models. Conversely, administration of recombinant FGF4 reduced hepatocellular apoptosis and rectified immune imbalance, thereby mitigating liver damage. The beneficial effects of FGF4 were mediated by hepatocellular FGF receptor 4, which activated the Ca2+/calmodulin-dependent protein kinasekinase 2 (CaMKKβ) and its downstream phosphatase and tensin homologue-induced putative kinase 1 (PINK1)-dependent B-cell lymphoma 2-like protein 1-isoform L (Bcl-XL) signalling axis in the mitochondria. Hence, FGF4 serves as an early response factor and plays a protective role against ILI, suggesting a therapeutic potential of FGF4 and its analogue for treating clinical immune disorder-related liver injuries.

Remodelers of the vascular microenvironment: The effect of biopolymeric hydrogels on vascular diseases

Vascular disease is the leading health problem worldwide. Vascular microenvironment encompasses diverse cell types, including those within the vascular wall, blood cells, stromal cells, and immune cells. Initiation of the inflammatory state of the vascular microenvironment and changes in its mechanics can profoundly affect vascular homeostasis. Biomedical materials play a crucial role in modern medicine, hydrogels, characterized by their high-water content, have been increasingly utilized as a three-dimensional interaction network. In recent times, the remarkable progress in utilizing hydrogels and understanding vascular microenvironment have enabled the treatment of vascular diseases. In this review, we give an emphasis on the utilization of hydrogels and their advantages in the various vascular diseases including atherosclerosis, aneurysm, vascular ulcers of the lower limbs and myocardial infarction. Further, we highlight the importance and advantages of hydrogels as artificial microenvironments.

Targeting S100A9 Prevents β-Adrenergic Activation-Induced Cardiac Injury

Altered cardiac innate immunity is highly associated with the progression of cardiac disease states and heart failure. S100A8/A9 is an important component of damage-associated molecular patterns (DAMPs) that is critically involved in the pathogenesis of heart failure, thus considered a promising target for pharmacological intervention. In the current study, initially, we validated the role of S100A8/A9 in contributing to cardiac injury and heart failure via the overactivation of the β-adrenergic pathway and tested the potential use of paquinimod as a pharmacological intervention of S100A8/A9 activation in preventing cardiac dysfunction, collagen deposition, inflammation, and immune cell infiltration in β-adrenergic overactivation-mediated heart failure. This finding was further confirmed by the cardiomyocyte-specific silencing of S100A9 via the use of the adeno-associated virus (AAV) 9-mediated short hairpin RNA (shRNA) gene silencing system. Most importantly, in the assessment of the underlying cellular mechanism by which activated S100A8/A9 cause aggravated progression of cardiac fibrosis and heart failure, we discovered that the activated S100A8/A9 can promote fibroblast-macrophage interaction, independent of inflammation, which is likely a key mechanism leading to the enhanced collagen production. Our results revealed that targeting S100A9 provides dual beneficial effects, which is not only a strategy to counteract cardiac inflammation but also preclude cardiac fibroblast-macrophage interactions. The findings of this study also indicate that targeting S100A9 could be a promising strategy for addressing cardiac fibrosis, potentially leading to future drug development.

Model informed precision medicine of Chinese herbal medicines formulas-A multi-scale mechanistic intelligent model

Recent trends suggest that Chinese herbal medicine formulas (CHM formulas) are promising treatments for complex diseases. To characterize the precise syndromes, precise diseases and precise targets of the precise targets between complex diseases and CHM formulas, we developed an artificial intelligence-based quantitative predictive algorithm (DeepTCM). DeepTCM has gone through multilevel model calibration and validation against a comprehensive set of herb and disease data so that it accurately captures the complex cellular signaling, molecular and theoretical levels of traditional Chinese medicine (TCM). As an example, our model simulated the optimal CHM formulas for the treatment of coronary heart disease (CHD) with depression, and through model sensitivity analysis, we calculated the balanced scoring of the formulas. Furthermore, we constructed a biological knowledge graph representing interactions by associating herb-target and gene-disease interactions. Finally, we experimentally confirmed the therapeutic effect and pharmacological mechanism of a novel model-predicted intervention in humans and mice. This novel multiscale model opened up a new avenue to combine "disease syndrome" and "macro micro" system modeling to facilitate translational research in CHM formulas.

One Endothelium-Targeted Combined Nucleic Acid Delivery System for Myocardial Infarction Therapy

Acute myocardial infarction (MI) and ischemic heart disease are the leading causes of heart failure and mortality. Currently, research on MI treatment is focused on angiogenic and anti-inflammatory therapies. Although endothelial cells (ECs) are critical for triggering inflammation and angiogenesis, no approach has targeted them for the treatment of MI. In this study, we proposed a nonviral combined nucleic acid delivery system consisting of an EC-specific polycation (CRPPR-grafted ethanolamine-modified poly(glycidyl methacrylate), CPC) that can efficiently codeliver siR-ICAM1 and pCXCL12 for the treatment of MI. Animals treated with the combination therapy exhibited better cardiac function than those treated with each nucleic acid alone. In particular, the combination therapy of CPC/siR-ICAM1 and CPC/pCXCL12 significantly improved cardiac systolic function, anti-inflammatory responses, and angiogenesis compared to the control group. In conclusion, CPC-based combined gene delivery systems show impressive performance in the treatment of MI and provide a programmed strategy for the development of codelivery systems for various EC-related diseases.

Beyond host defense and tissue injury: the emerging role of neutrophils in tissue repair

Neutrophils, the most abundant immune cells in human blood, play a fundamental role in host defense against invading pathogens and tissue injury. Neutrophils carry potentially lethal weaponry to the affected site. Inadvertent and perpetual neutrophil activation could lead to nonresolving inflammation and tissue damage, a unifying mechanism of many common diseases. The prevailing view emphasizes the dichotomy of their function, host defense versus tissue damage. However, tissue injury may also persist during neutropenia, which is associated with disease severity and poor outcome. Numerous studies highlight neutrophil phenotypic heterogeneity and functional versatility, indicating that neutrophils play more complex roles than previously thought. Emerging evidence indicates that neutrophils actively orchestrate resolution of inflammation and tissue repair and facilitate return to homeostasis. Thus, neutrophils mobilize multiple mechanisms to limit the inflammatory reaction, assure debris removal, matrix remodeling, cytokine scavenging, macrophage reprogramming, and angiogenesis. In this review, we will summarize the homeostatic and tissue-reparative functions and mechanisms of neutrophils across organs. We will also discuss how the healing power of neutrophils might be harnessed to develop novel resolution and repair-promoting therapies while maintaining their defense functions.

Reticulon 3 deficiency ameliorates post-myocardial infarction heart failure by alleviating mitochondrial dysfunction and inflammation

Multiple molecular mechanisms are involved in the development of heart failure (HF) after myocardial infarction (MI). However, interventions targeting these pathological processes alone remain clinically ineffective. Therefore, it is essential to identify new therapeutic targets for alleviating cardiac dysfunction after MI. Here, gain- and loss-of-function approaches were used to investigate the role of reticulon 3 (RTN3) in HF after MI. We found that RTN3 was elevated in the myocardium of patients with HF and mice with MI. Cardiomyocyte-specific RTN3 overexpression decreased systolic function in mice under physiological conditions and exacerbated the development of HF induced by MI. Conversely, RTN3 knockout alleviated cardiac dysfunction after MI. Mechanistically, RTN3 bound and mediated heat shock protein beta-1 (HSPB1) translocation from the cytosol to the endoplasmic reticulum. The reduction of cytosolic HSPB1 was responsible for the elevation of TLR4, which impaired mitochondrial function and promoted inflammation through toll-like receptor 4 (TLR4)/peroxisome proliferator-activated receptor gamma coactivator-1 alpha(PGC-1α) and TLR4/Nuclear factor-kappa B(NFκB) pathways, respectively. Furthermore, the HSPB1 inhibitor reversed the protective effect of RTN3 knockout on MI. Additionally, elevated plasma RTN3 level is associated with decreased cardiac function in patients with acute MI. This study identified RTN3 as a critical driver of HF after MI and suggests targeting RTN3 as a promising therapeutic strategy for MI and related cardiovascular diseases.

A pilot study of S100A4, S100A8/A9, and S100A12 in dilated cardiomyopathy: novel biomarkers for diagnosis or prognosis?

AIMS

Circulating biomarkers can provide important information for the diagnosis and prognosis of dilated cardiomyopathy (DCM). We explored novel biomarkers for the diagnosis and prognosis of DCM to improve clinical decision-making.

METHODS AND RESULTS

A total of 238 DCM patients and 65 control were consecutively enrolled at Zhongshan Hospital between January 2017 and January 2019. In the screening set, four DCM patients and four controls underwent measurements of serum proteomic analysis. Seventy-six differentially expressed circulating proteins were screened by data-independent acquisition proteomics, and three of these proteins (S100A4, S100A8/A9, and S100A12) were validated by multiple-reaction monitoring-mass spectrometry. In the validation set, subsequently, a total of 234 DCM patients and 61 control subjects were evaluated by enzyme-linked immunosorbent assay. Circulating S100A4, S100A8/A9, and S100A12 were significantly increased in DCM patients (P < 0.001). These three proteins were significant positively correlated with other parameters, such as Lg (NT-proBNP), IL-1β, TGF-β, CRP, left ventricular end-diastolic diameter, and left ventricular end-systolic diameter, whereas they were negatively correlated with left ventricular ejection fraction, respectively (P < 0.05). The receiver operator characteristic curve showed the combination of S100A4, S100A8/A9, and S100A12 [area under curve (AUC) 0.88, 95% confidence interval (CI) 0.84-0.93] was better than single S100A4 (AUC 0.74, 95% CI 0.68-0.81), S100A8/A9 (AUC 0.82, 95% CI 0.77-0.88), or S100A12 (AUC 0.80, 95% CI 0.72-0.88) in the diagnosis of DCM (P < 0.01). After a median follow-up period of 33.5 months, 110 patients (47.01%) experienced major adverse cardiac events (MACEs), including 46 who had cardiac deaths and 64 who had heart failure rehospitalizations. Kaplan-Meier analysis indicated that the DCM patients with ≥75th percentile level of S100A4 had a significantly higher incidence of MACEs than those with <75th percentile level of S100A4 (61.40% vs. 42.37%, P < 0.05). There were no significant differences of MACE rate among DCM patients with different concentrations of S100A8/A9 and S100A12 (P > 0.05). Cox proportional hazards regression analysis revealed that S100A4 [≥75th percentile vs. <75th percentile: hazard ratio (HR) 1.65; 95% CI 1.11-2.45] remained significant independent predictors for MACEs (P < 0.05); however, S100A8/A9 and S100A12 were not independent factors for predicting MACE (P ≥ 0.05).

CONCLUSIONS

S100A4, S100A8/A9, and S100A12 may be additional diagnostic tools for human DCM recognition, and the combination of these three indicators helped to improve the accuracy of a single index to diagnose DCM. Additionally, S100A4 was identified as a significant predictor of prognosis in patients with DCM.

Current understanding of macrophages in intracranial aneurysm: relevant etiological manifestations, signaling modulation and therapeutic strategies

Macrophages activation and inflammatory response play crucial roles in intracranial aneurysm (IA) formation and progression. The outcome of ruptured IA is considerably poor, and the mechanisms that trigger IA progression and rupture remain to be clarified, thereby developing effective therapy to prevent subarachnoid hemorrhage (SAH) become difficult. Recently, climbing evidences have been expanding our understanding of the macrophages relevant IA pathogenesis, such as immune cells population, inflammatory activation, intra-/inter-cellular signaling transductions and drug administration responses. Crosstalk between macrophages disorder, inflammation and cellular signaling transduction aggravates the devastating consequences of IA. Illustrating the pros and cons mechanisms of macrophages in IA progression are expected to achieve more efficient treatment interventions. In this review, we summarized the current advanced knowledge of macrophages activation, infiltration, polarization and inflammatory responses in IA occurrence and development, as well as the most relevant NF-κB, signal transducer and activator of transcription 1 (STAT1) and Toll-Like Receptor 4 (TLR4) regulatory signaling modulation. The understanding of macrophages regulatory mechanisms is important for IA patients' clinical outcomes. Gaining insight into the macrophages regulation potentially contributes to more precise IA interventions and will also greatly facilitate the development of novel medical therapy.

Inhibiting anti-angiogenic VEGF165b activates a miR-17-20a-Calcipressin-3 pathway that revascularizes ischemic muscle in peripheral artery disease

BACKGROUND

VEGF165a increases the expression of the microRNA-17-92 cluster, promoting developmental, retinal, and tumor angiogenesis. We have previously shown that VEGF165b, an alternatively spliced anti-angiogenic VEGF-A isoform, inhibits the VEGFR-STAT3 pathway in ischemic endothelial cells (ECs) to decrease their angiogenic capacity. In ischemic macrophages (Møs), VEGF165b inhibits VEGFR1 to induce S100A8/A9 expression, which drives M1-like polarization. Our current study aims to determine whether VEGF165b inhibition promotes perfusion recovery by regulating the microRNA(miR)-17-92 cluster in preclinical PAD.

METHODS

Femoral artery ligation and resection was used as a preclinical PAD model. Hypoxia serum starvation (HSS) was used as an in vitro PAD model. VEGF165b was inhibited/neutralized by an isoform-specific VEGF165b antibody.

RESULTS

Here, we show that VEGF165b-inhibition induces the expression of miR-17-20a (within miR-17-92 (miR-17-18a-19a-19b-20a-92) cluster) in HSS-ECs and HSS-Møs vs. respective normal and/or isotype-matched IgG controls to enhance perfusion recovery. Consistent with the bioinformatics analysis that revealed RCAN3 as a common target of miR-17 and miR-20a, Argonaute-2 pull-down assays showed decreased miR-17-20a expression and higher RCAN3 expression in the RNA-induced silencing complex of HSS-ECs and HSS-Møs vs. respective controls. Inhibiting miR-17-20a induced RCAN3 levels to decrease ischemic angiogenesis and promoted M1-like polarization to impair perfusion recovery. Finally, using STAT3 inhibitors, S100A8/A9 silencers, and VEGFR1-deficient ECs and Møs, we show that VEGF165b-inhibition activates the miR-17-20a-RCAN3 pathway independent of VEGFR1-STAT3 or VEGFR1-S100A8/A9 in ischemic-ECs and ischemic-Møs respectively.

CONCLUSIONS

Our data revealed a hereunto unrecognized therapeutic 'miR-17-20a-RCAN3' pathway in the ischemic vasculature that is VEGFR1-STAT3/S100A8/A9 independent and is activated only upon VEGF165b-inhibition in PAD.

ATF3 coordinates the survival and proliferation of cardiac macrophages and protects against ischemia-reperfusion injury

Cardiac resident MerTK+ macrophages exert multiple protective roles after ischemic injury; however, the mechanisms regulating their fate are not fully understood. In the present study, we show that the GAS6-inducible transcription factor, activating transcription factor 3 (ATF3), prevents apoptosis of MerTK+ macrophages after ischemia-reperfusion (IR) injury by repressing the transcription of multiple genes involved in type I interferon expression (Ifih1 and Ifnb1) and apoptosis (Apaf1). Mice lacking ATF3 in cardiac macrophages or myeloid cells showed excessive loss of MerTK+ cardiac macrophages, poor angiogenesis and worse heart dysfunction after IR, which were rescued by the transfer of MerTK+ cardiac macrophages. GAS6 administration improved cardiac repair in an ATF3-dependent manner. Finally, we showed a negative association of GAS6 and ATF3 expression with the risk of major adverse cardiac events in patients with ischemic heart disease. These results indicate that the GAS6-ATF3 axis has a protective role against IR injury by regulating MerTK+ cardiac macrophage survival and/or proliferation.

A proteome-wide screen identifies the calcium binding proteins, S100A8/S100A9, as clinically relevant therapeutic targets in aortic dissection

Aortic dissection (AD) is a fatal cardiovascular disease with limited pharmacotherapies. To discover novel therapeutic targets for AD, the present study was conducted on ascending aorta samples from AD patients versus those from control subjects using proteomic analysis. Integrated proteomic data analysis identified S100 calcium-binding proteins A8 and A9 (S100A8/A9) as new therapeutic targets for AD. As assessed by ELISA, the circulating levels of S100A8/A9 were elevated in AD patients. In addition, we validated the upregulation of S100A8/A9 in a mouse model of AD. In vitro and in vivo studies substantiated that S100A8/A9, as danger-associated molecular pattern molecules, promotes the smooth muscle cells phenotypic switch by inhibiting serum response factor (SRF) activity but elevating NF-κB dependent inflammatory response. Depletion of S100A8/A9 attenuates the occurrence and development of AD. As a proof of concept, we tested the safety and efficacy of pharmacological inhibition of S100A8/A9 by ABR-25757 (paquinimod) in a mouse model of AD. We observed that ABR-25757 ameliorated the incidence of rupture and improved elastin morphology associated with AD. Further single-cell RNA sequencing disclosed that the phenotypic switch of vascular smooth muscle cells (VSMCs) and inflammatory response pathways were responsible for ABR-25757-mediated protection against AD. Thus, this study reveals the regulatory mechanism of S100A8/A9 in AD and offers a potential therapeutic avenue to treat AD by targeting S100A8/A9.

hUC-MSC-EV-miR-24 enhances the protective effect of dexmedetomidine preconditioning against myocardial ischemia-reperfusion injury through the KEAP1/Nrf2/HO-1 signaling

The cardioprotective effect of microRNAs (miRNAs) on myocardial ischemic-reperfusion (I/R) injury has been documented. Here, we aim to decipher the mechanism of miR-24 delivered by human umbilical cord mesenchymal stem cell-derived extracellular vesicles (hUC-MSC-EVs) in myocardial I/R injury after dexmedetomidine (DEX) preconditioning. We collected and identified hUC-MSCs and extracted EVs, which were co-cultured with DEX-preconditioned hypoxia/reoxygenation (H/R) cardiomyocyte models or injected into I/R mouse models. The cardiomyocytes and myocardial injury were evaluated by molecular biology experiments. miR-24 was highly expressed in hUC-MSC-EVs. hUC-MSC-EVs could transfer miR-24 into cardiomyocytes where miR-24 augmented cell viability and inhibited cell apoptosis after DEX preconditioning. In the co-culture system of RAW264.7 macrophages with hUC-MSC-EVs, miR-24 promoted M2-type polarization of macrophages and reduced M1-type macrophage polarization. Mechanistically, miR-24 targeted KEAP1 and inhibited its expression, resulting in disruption of the Nrf2/HO-1 signaling. In vivo data confirmed that miR-24 delivered by hUC-MSC-EVs enhanced the suppressing effect of DEX preconditioning on inflammation and apoptosis in rats following myocardial I/R injury. Overall, miR-24 delivered by hUC-MSC-EVs can promote M2 polarization of macrophages and enhance the protective effect of DEX preconditioning on myocardial I/R injury by down-regulating the KEAP1/Nrf2/HO-1 signaling axis.

An injectable carrier for spatiotemporal and sequential release of therapeutic substances to treat myocardial infarction

Myocardial infarction (MI) has become the primary cause of cardiovascular mortality, while the current treatment methods in clinical all have their shortcomings. Injectable biomaterials have emerged as a promising solution for cardiac tissue repair after MI. In this study, we designed a smart multifunctional carrier that could meet the treatment needs of different MI pathological processes by programmatically releasing different therapeutic substances. The carrier could respond to inflammatory microenvironment in the early stage of MI with rapid release of curcumin (Cur), and then sustained release recombinant humanized collagen type III (rhCol III) to treat MI. The rapid release of Cur reduced inflammation and apoptosis in the early stages, while the sustained release of rhCol III promoted angiogenesis and cardiac repair in the later stages. In vitro and in vivo results suggested that the multifunctional carrier could effectively improve cardiac function, promote the repair of infarcted tissue, and inhibit ventricular remodeling by reducing cell apoptosis and inflammation, and promoting angiogenesis in the different pathological processes of MI. Therefore, this programmed-release carrier provides a promising protocol for MI therapy.

Neutrophil counts and cardiovascular disease

BACKGROUND AND AIMS

Anti-inflammatory trials have shown considerable benefits for cardiovascular disease. High neutrophil counts, an easily accessible inflammation biomarker, are associated with atherosclerosis in experimental studies. This study aimed to investigate the associations between neutrophil counts and risk of nine cardiovascular endpoints using observational and genetic approaches.

METHODS

Observational studies were conducted in the Copenhagen General Population Study (n = 101 730). Genetic studies were firstly performed using one-sample Mendelian randomization (MR) with individual-level data from the UK Biobank (n = 365 913); secondly, two-sample MR analyses were performed using summary-level data from the Blood Cell Consortium (n = 563 085). Outcomes included ischaemic heart disease, myocardial infarction, peripheral arterial disease, ischaemic cerebrovascular disease, ischaemic stroke, vascular-related dementia, vascular dementia, heart failure, and atrial fibrillation.

RESULTS

Observational analyses showed associations between high neutrophil counts with high risks of all outcomes. In the UK Biobank, odds ratios (95% confidence intervals) per 1-SD higher genetically predicted neutrophil counts were 1.15 (1.08, 1.21) for ischaemic heart disease, 1.22 (1.12, 1.34) for myocardial infarction, and 1.19 (1.04, 1.36) for peripheral arterial disease; similar results were observed in men and women separately. In two-sample MR, corresponding estimates were 1.14 (1.05, 1.23) for ischaemic heart disease and 1.11 (1.02, 1.20) for myocardial infarction; multiple sensitivity analyses showed consistent results. No robust associations in two-sample MR analyses were found for other types of leucocytes.

CONCLUSIONS

Observational and genetically determined high neutrophil counts were associated with atherosclerotic cardiovascular disease, supporting that high blood neutrophil counts is a causal risk factor for atherosclerotic cardiovascular disease.

S100A8/A9: An emerging player in sepsis and sepsis-induced organ injury

Sepsis, the foremost contributor to mortality in intensive care unit patients, arises from an uncontrolled systemic response to invading infections, resulting in extensive harm across multiple organs and systems. Recently, S100A8/A9 has emerged as a promising biomarker for sepsis and sepsis-induced organ injury, and targeting S100A8/A9 appeared to ameliorate inflammation-induced tissue damage and improve adverse outcomes. S100A8/A9, a calcium-binding heterodimer mainly found in neutrophils and monocytes, serves as a causative molecule with pro-inflammatory and immunosuppressive properties, which are vital in the pathogenesis of sepsis. Therefore, improving our comprehension of how S100A8/A9 acts as a pathological player in the development of sepsis is imperative for advancing research on sepsis. Our review is the first-to the best of our knowledge-to discuss the biology of S100A8/A9 and its release mechanisms, summarize recent advances concerning the vital roles of S100A8/A9 in sepsis and the consequential organ damage, and underscore its potential as a promising diagnostic biomarker and therapeutic target for sepsis.

SIRT3-dependent mitochondrial redox homeostasis mitigates CHK1 inhibition combined with gemcitabine treatment induced cardiotoxicity in hiPSC-CMs and mice

Administration of CHK1-targeted anticancer therapies is associated with an increased cumulative risk of cardiac complications, which is further amplified when combined with gemcitabine. However, the underlying mechanisms remain elusive. In this study, we generated hiPSC-CMs and murine models to elucidate the mechanisms underlying CHK1 inhibition combined with gemcitabine-induced cardiotoxicity and identify potential targets for cardioprotection. Mice were intraperitoneally injected with 25 mg/kg CHK1 inhibitor AZD7762 and 20 mg/kg gemcitabine for 3 weeks. hiPSC-CMs and NMCMs were incubated with 0.5 uM AZD7762 and 0.1 uM gemcitabine for 24 h. Both pharmacological inhibition or genetic deletion of CHK1 and administration of gemcitabine induced mtROS overproduction and pyroptosis in cardiomyocytes by disrupting mitochondrial respiration, ultimately causing heart atrophy and cardiac dysfunction in mice. These toxic effects were further exacerbated with combination administration. Using mitochondria-targeting sequence-directed vectors to overexpress CHK1 in cardiomyocyte (CM) mitochondria, we identified the localization of CHK1 in CM mitochondria and its crucial role in maintaining mitochondrial redox homeostasis for the first time. Mitochondrial CHK1 function loss mediated the cardiotoxicity induced by AZD7762 and CHK1-knockout. Mechanistically, mitochondrial CHK1 directly phosphorylates SIRT3 and promotes its expression within mitochondria. On the contrary, both AZD7762 or CHK1-knockout and gemcitabine decreased mitochondrial SIRT3 abundance, thus resulting in respiration dysfunction. Further hiPSC-CMs and mice experiments demonstrated that SIRT3 overexpression maintained mitochondrial function while alleviating CM pyroptosis, and thereby improving mice cardiac function. In summary, our results suggest that targeting SIRT3 could represent a novel therapeutic approach for clinical prevention and treatment of cardiotoxicity induced by CHK1 inhibition and gemcitabine.

Deficiency of S100A8/A9 attenuates pulmonary microvascular leakage in septic mice

BACKGROUND

We have reported a positive correlation between S100 calcium-binding protein (S100) A8/S100A9 and sepsis-induced lung damage before. However, limited knowledge exists concerning the biological role of S100A8/A9 in pulmonary vascular endothelial barrier dysfunction, as well as the diagnostic value of S100A8/A9 in sepsis.

METHODS

Sepsis was induced in C57BL/6J mice and S100A9-knockout (KO) mice through the cecal ligation and puncture (CLP). Pulmonary vascular leakage was determined by measuring extravasated Evans blue (EB). Reverse transcription polymerase chain reaction and the histological score were used to evaluate inflammation and lung injury, respectively. Recombinant S100A8/A9 (rhS100A8/A9) was used to identify the effects of S100A8/A9 on endothelial barrier dysfunction in human umbilical vein endothelial cells (HUVECs). Additionally, the diagnostic value of S100A8/A9 in sepsis was assessed using receiver operating characteristic.

RESULTS

S100A8/A9 expression was up-regulated in the lungs of CLP-operated mice. S100A9 KO significantly reversed CLP-induced hypothermia and hypotension, resulting in an improved survival rate. S100A9 KO also decreased the inflammatory response, EB leakage, and histological scores in the lungs of CLP-operated mice. Occludin and VE-cadherin expressions were decreased in the lungs of CLP-operated mice; However, S100A9 KO attenuated this decrease. Moreover, CLP-induced signal transducer and activator of transcription 3 (STAT3) and p38/extracellular signal-regulated kinase (ERK) signalling activation and apoptosis were mitigated by S100A9 KO in lungs. In addition, rhS100A8/A9 administration significantly decreased occludin and VE-cadherin expressions, increased the phosphorylated (p)-ERK/ERK, p-p38/p38, and B-cell leukaemia/lymphoma 2 protein (Bcl-2)-associated X protein/Bcl-2 ratios in HUVECs.

CONCLUSION

The present study demonstrated S100A8/A9 aggravated sepsis-induced pulmonary inflammation, vascular permeability, and lung injury. This was achieved, at least partially, by activating the P38/STAT3/ERK signalling pathways. Moreover, S100A8/A9 showed the potential as a biomarker for sepsis diagnosis.

Exercise mitigates age-related metabolic diseases by improving mitochondrial dysfunction

The benefits of regular physical activity are related to delaying and reversing the onset of ageing and age-related disorders, including cardiomyopathy, neurodegenerative diseases, cancer, obesity, diabetes, and fatty liver diseases. However, the molecular mechanisms of the benefits of exercise or physical activity on ageing and age-related disorders remain poorly understood. Mitochondrial dysfunction is implicated in the pathogenesis of ageing and age-related metabolic diseases. Mitochondrial health is an important mediator of cellular function. Therefore, exercise alleviates metabolic diseases in individuals with advancing ageing and age-related diseases by the remarkable promotion of mitochondrial biogenesis and function. Exerkines are identified as signaling moieties released in response to exercise. Exerkines released by exercise have potential roles in improving mitochondrial dysfunction in response to age-related disorders. This review comprehensive summarizes the benefits of exercise in metabolic diseases, linking mitochondrial dysfunction to the onset of age-related diseases. Using relevant examples utilizing this approach, the possibility of designing therapeutic interventions based on these molecular mechanisms is addressed.

CaMKII, 'jack of all trades' in inflammation during cardiac ischemia/reperfusion injury

Myocardial infarction and revascularization cause cardiac ischemia/reperfusion (I/R) injury featuring cardiomyocyte death and inflammation. The Ca2+/calmodulin dependent protein kinase II (CaMKII) family are serine/ threonine protein kinases that are involved in I/R injury. CaMKII exists in four different isoforms, α, β, γ, and δ. In the heart, CaMKII-δ is the predominant isoform，with multiple splicing variants, such as δB, δC and δ9. During I/R, elevated intracellular Ca2+ concentrations and reactive oxygen species activate CaMKII. In this review, we summarized the regulation and function of CaMKII in multiple cell types including cardiomyocytes, endothelial cells, and macrophages during I/R. We conclude that CaMKII mediates inflammation in the microenvironment of the myocardium, resulting in cell dysfunction, elevated inflammation, and cell death. However, different CaMKII-δ variants exhibit distinct or even opposite functions. Therefore, reagents/approaches that selectively target specific CaMKII isoforms and variants are needed for evaluating and counteracting the exact role of CaMKII in I/R injury and developing effective treatments against I/R injury.

Inflammation in Myocardial Ischemia/Reperfusion Injury: Underlying Mechanisms and Therapeutic Potential

Acute myocardial infarction (MI) occurs when blood flow to the myocardium is restricted, leading to cardiac damage and massive loss of viable cardiomyocytes. Timely restoration of coronary flow is considered the gold standard treatment for MI patients and limits infarct size; however, this intervention, known as reperfusion, initiates a complex pathological process that somewhat paradoxically also contributes to cardiac injury. Despite being a sterile environment, ischemia/reperfusion (I/R) injury triggers inflammation, which contributes to infarct expansion and subsequent cardiac remodeling and wound healing. The immune response is comprised of subsets of both myeloid and lymphoid-derived cells that act in concert to modulate the pathogenesis and resolution of I/R injury. Multiple mechanisms, including altered metabolic status, regulate immune cell activation and function in the setting of acute MI, yet our understanding remains incomplete. While numerous studies demonstrated cardiac benefit following strategies that target inflammation in preclinical models, therapeutic attempts to mitigate I/R injury in patients were less successful. Therefore, further investigation leveraging emerging technologies is needed to better characterize this intricate inflammatory response and elucidate its influence on cardiac injury and the progression to heart failure.

Viral nanoparticle vaccines against S100A9 reduce lung tumor seeding and metastasis

Metastatic cancer accounts for 90% of all cancer-related deaths and continues to be one of the toughest challenges in cancer treatment. A growing body of data indicates that S100A9, a major regulator of inflammation, plays a central role in cancer progression and metastasis, particularly in the lungs, where S100A9 forms a premetastatic niche. Thus, we developed a vaccine against S100A9 derived from plant viruses and virus-like particles. Using multiple tumor mouse models, we demonstrate the effectiveness of the S100A9 vaccine candidates in preventing tumor seeding within the lungs and outgrowth of metastatic disease. The elicited antibodies showed high specificity toward S100A9 without cross-reactivity toward S100A8, another member of the S100A family. When tested in metastatic mouse models of breast cancer and melanoma, the vaccines significantly reduced lung tumor nodules after intravenous challenge or postsurgical removal of the primary tumor. Mechanistically, the vaccines reduce the levels of S100A9 within the lungs and sera, thereby increasing the expression of immunostimulatory cytokines with antitumor function [(interleukin) IL-12 and interferonγ] while reducing levels of immunosuppressive cytokines (IL-10 and transforming growth factorβ). This also correlated with decreased myeloid-derived suppressor cell populations within the lungs. This work has wide-ranging impact, as S100A9 is overexpressed in multiple cancers and linked with poor prognosis in cancer patients. The data presented lay the foundation for the development of therapies and vaccines targeting S100A9 to prevent metastasis.