The AIM2 inflammasome exacerbates atherosclerosis in clonal haematopoiesis

Combined Effects of Clonal Hematopoiesis and Carotid Stenosis on Cardiovascular Mortality

BACKGROUND

The expansion of hematopoietic stem cells caused by acquired somatic mutations (clonal hematopoiesis [CH]) is a novel cardiovascular risk factor. The prognostic value of CH in patients with carotid atherosclerosis remains to be evaluated.

OBJECTIVES

This study assessed the prognostic significance of CH in patients with atherosclerosis as detected by ultrasound of the carotid artery.

METHODS

We applied deep sequencing of selected genomic regions within the genes DNMT3A, TET2, ASXL1, and JAK2 to screen for CH in 968 prospectively collected patients with asymptomatic carotid atherosclerosis evaluated by duplex sonography.

RESULTS

We detected clonal markers at variant allele frequency ≥2% in 133 (13.7%) of 968 patients (median age 69.2 years), with increasing prevalence at advanced age. Multivariate analyses including age and established cardiovascular risk factors revealed overall presence of CH to be significantly associated with increased risk of cardiovascular death (HR: 1.50; 95% CI: 1.12-2.00; P = 0.007), reflected also at the single gene level. The effect of CH was more pronounced in older patients and independent of the patients' inflammatory status as measured by high-sensitivity C-reactive protein. Simultaneous assessment of CH and degree of carotid stenosis revealed combined effects on cardiovascular mortality, depicted by a superior risk for patients with >50% stenosis and concomitant CH (adjusted HR: 1.60; 95% CI: 1.08-2.38; P = 0.020).

CONCLUSIONS

CH status in combination with the extent of carotid atherosclerosis jointly predict long-term mortality. Determination of CH can provide additional prognostic information in patients with asymptomatic carotid atherosclerosis.

Immunoreactive Microenvironment Modulator GBP5 Suppresses Ovarian Cancer Progression by Inducing Canonical Pyroptosis

Ovarian cancer has the highest mortality among gynecological malignancies, and exploring effective strategies to reverse the immunosuppressive tumor microenvironment in patients remains a pressing scientific challenge. In this study, we identified a pyroptosis-related protective factor, GBP5, which significantly inhibits the growth of ovarian cancer cells and patient-derived ovarian cancer organoids, impeding the invasion and migration of ovarian cancer cells. Results of immunohistochemistry and external single-cell data verification were consistent. Further research confirmed that GBP5 in ovarian cancer cell can induce canonical pyroptosis through JAK2/STAT1 pathway, thereby restraining the progression of ovarian cancer. Interestingly, in this study, we also discovered that ovarian cancer cells with high GBP5 expression exhibit increased expressions of CXCL9/10/11 in a co-culture assay. Subsequent immune cell infiltration analyses revealed the remodeling of immunosuppressive microenvironment in ovarian cancer patients, characterized by increased infiltration and polarization of M1 macrophages. External immunotherapy database analysis showed profound potential for the application of GBP5 in immunotherapy strategies for ovarian cancer. Overall, our study demonstrates that the protective factor GBP5 significantly inhibits ovarian cancer progression, triggering canonical pyroptosis through the JAK2-STAT1 pathway. Driven by its pro-inflammatory nature, it can also enhance M1 macrophages polarization and reverse immunosuppressive microenvironment, thus providing new insights for ovarian cancer treatment.

Clonal Hematopoiesis of Indeterminate Potential With Loss of Tet2 Enhances Risk for Atrial Fibrillation Through Nlrp3 Inflammasome Activation

BACKGROUND

Clonal hematopoiesis of indeterminate potential (CHIP), a common age-associated phenomenon, associates with increased risk of both hematological malignancy and cardiovascular disease. Although CHIP is known to increase the risk of myocardial infarction and heart failure, the influence of CHIP in cardiac arrhythmias, such as atrial fibrillation (AF), is less explored.

METHODS

CHIP prevalence was determined in the UK Biobank, and incident AF analysis was stratified by CHIP status and clone size using Cox proportional hazard models. Lethally irradiated mice were transplanted with hematopoietic-specific loss of Tet2, hematopoietic-specific loss of Tet2 and Nlrp3, or wild-type control and fed a Western diet, compounded with or without NLRP3 (NLR [NACHT, LRR {leucine rich repeat}] family pyrin domain containing protein 3) inhibitor, NP3-361, for 6 to 9 weeks. Mice underwent in vivo invasive electrophysiology studies and ex vivo optical mapping. Cardiomyocytes from Ldlr-/- mice with hematopoietic-specific loss of Tet2 or wild-type control and fed a Western diet were isolated to evaluate calcium signaling dynamics and analysis. Cocultures of pluripotent stem cell-derived atrial cardiomyocytes were incubated with Tet2-deficient bone marrow-derived macrophages, wild-type control, or cytokines IL-1β (interleukin 1β) or IL-6 (interleukin 6).

RESULTS

Analysis of the UK Biobank showed individuals with CHIP, in particular TET2 CHIP, have increased incident AF. Hematopoietic-specific inactivation of Tet2 increases AF propensity in atherogenic and nonatherogenic mouse models and is associated with increased Nlrp3 expression and CaMKII (Ca2+/calmodulin-dependent protein kinase II) activation, with AF susceptibility prevented by inactivation of Nlrp3. Cardiomyocytes isolated from Ldlr-/- mice with hematopoietic inactivation of Tet2 and fed a Western diet have impaired calcium release from the sarcoplasmic reticulum into the cytosol, contributing to atrial arrhythmogenesis. Abnormal sarcoplasmic reticulum calcium release was recapitulated in cocultures of cardiomyocytes with the addition of Tet2-deficient macrophages or cytokines IL-1β or IL-6.

CONCLUSIONS

We identified a modest association between CHIP, particularly TET2 CHIP, and incident AF in the UK Biobank population. In a mouse model of AF resulting from hematopoietic-specific inactivation of Tet2, we propose altered calcium handling as an arrhythmogenic mechanism, dependent on Nlrp3 inflammasome activation. Our data are in keeping with previous studies of CHIP in cardiovascular disease, and further studies into the therapeutic potential of NLRP3 inhibition for individuals with TET2 CHIP may be warranted.

Fufang Zhenzhu Tiaozhi (FTZ) suppression of macrophage pyroptosis: Key to stabilizing rupture-prone plaques

BACKGROUND

Research on the Chinese herbal formula Fufang Zhenzhu Tiaozhi (FTZ) has demonstrated its effectiveness in treating hyperlipidemia and glycolipid metabolic disorders. Additionally, FTZ has shown inhibitory effects on oxidative stress, regulation of lipid metabolism, and reduction of inflammation in these conditions. However, the precise mechanisms through which FTZ modulates macrophage function in atherosclerosis remain incompletely understood. Therefore, this study aims to investigate whether FTZ can effectively stabilize rupture-prone plaques by suppressing macrophage pyroptosis and impeding the development of M1 macrophage polarization in ApoE-/- mice.

METHODS

To assess the impact of FTZ on macrophage function and atherosclerosis in ApoE-/- mice, we orally administered FTZ at a dosage of 1.2 g/kg body weight daily for 14 weeks. Levels of interleukin-18 and interleukin-1β were quantified using ELISA kits to gauge FTZ's influence on inflammation. Total cholesterol content was measured with a Cholesterol Assay Kit to evaluate FTZ's effect on lipid metabolism. Aortic tissues were stained with Oil Red O, and immunohistochemistry techniques were applied to assess atherosclerotic lesions and plaque stability. To evaluate the effects of FTZ on macrophage pyroptosis and oxidative damage, immunofluorescence staining was utilized. Additionally, we conducted an analysis of protein and mRNA expression levels of NLRP3 inflammasome-related genes and macrophage polarization-related genes using RT-PCR and western blotting techniques.

RESULTS

This study illustrates the potential therapeutic effectiveness of FTZ in mitigating the severity of atherosclerosis and improving serum lipid profiles by inhibiting inflammation. The observed enhancements in atherosclerosis severity and inflammation can be attributed to the suppression of NLRP3 inflammasome activity and M1 polarization by FTZ.

CONCLUSION

The current findings indicate that FTZ provides protection against atherosclerosis, positioning it as a promising candidate for novel therapies targeting atherosclerosis and related cardiovascular diseases.

The role of immune cells in different stages of atherosclerosis

Atherosclerosis is a chronic inflammatory disease characterized by the accumulation of immune cells in the intima of arteries. Experimental and clinical evidence shows that both innate and adaptive immunity orchestrate the progression of atherosclerosis. The heterogeneous nature of immune cells within atherosclerosis lesions is important. Studies utilizing high-dimensional mass spectrometry and single-cell RNA sequencing of leukocytes from atherosclerotic lesions show the diversity and adaptability of these immune cell subtypes. Their migration, compositional changes, phenotypic alterations, and adaptive responses are key features throughout atherosclerosis progression. Understanding how these immune cells and their subtypes affect atherogenesis would help to develop novel therapeutic approaches that control atherosclerosis progression. Precise targeting of specific immune system components involved in atherosclerosis, rather than broad suppression of the immune system with anti-inflammatory agents, can more accurately regulate the progress of atherosclerosis with fewer side effects. In this review, we cover the most recent advances in the field of atherosclerosis to understand the role of various immune cells on its development. We focus on the complex network of immune cells and the interaction between the innate immune system and adaptive immune system.

Disulfiram Reduces Atherosclerosis and Enhances Efferocytosis, Autophagy, and Atheroprotective Gut Microbiota in Hyperlipidemic Mice

BACKGROUND

Pyroptosis executor GsdmD (gasdermin D) promotes atherosclerosis in mice and humans. Disulfiram was recently shown to potently inhibit GsdmD, but the in vivo efficacy and mechanism of disulfiram's antiatherosclerotic activity is yet to be explored.

METHODS AND RESULTS

We used human/mouse macrophages, endothelial cells, and smooth muscle cells and a hyperlipidemic mouse model of atherosclerosis to determine disulfiram antiatherosclerotic efficacy and mechanism. The effects of disulfiram on several atheroprotective pathways such as autophagy, efferocytosis, phagocytosis, and gut microbiota were determined. Atomic force microscopy was used to determine the effects of disulfiram on the biophysical properties of the plasma membrane of macrophages. Disulfiram-fed hyperlipidemic apolipoprotein E-/- mice showed significantly reduced interleukin-1β release upon in vivo Nlrp3 (NLR family pyrin domain containing 3) inflammasome activation. Disulfiram-fed mice showed smaller atherosclerotic lesions (~27% and 29% reduction in males and females, respectively) and necrotic core areas (~50% and 46% reduction in males and females, respectively). Disulfiram induced autophagy in macrophages, smooth muscle cells, endothelial cells, hepatocytes/liver, and atherosclerotic plaques. Disulfiram modulated other atheroprotective pathways (eg, efferocytosis, phagocytosis) and gut microbiota. Disulfiram-treated macrophages showed enhanced phagocytosis/efferocytosis, with the mechanism being a marked increase in cell-surface expression of efferocytic receptor MerTK. Atomic force microscopy analysis revealed altered biophysical properties of disulfiram-treated macrophages, showing increased order-state of plasma membrane and increased adhesion strength. Furthermore, 16sRNA sequencing of disulfiram-fed hyperlipidemic mice showed highly significant enrichment in atheroprotective gut microbiota Akkermansia and a reduction in atherogenic Romboutsia species.

CONCLUSIONS

Taken together, our data show that disulfiram can simultaneously modulate several atheroprotective pathways in a GsdmD-dependent as well as GsdmD-independent manner.

Jak2 V617F clonal hematopoiesis promotes arterial thrombosis via platelet activation and cross talk

ABSTRACT

JAK2 V617F (JAK2VF) clonal hematopoiesis (CH) has been associated with atherothrombotic cardiovascular disease (CVD). We assessed the impact of Jak2VF CH on arterial thrombosis and explored the underlying mechanisms. A meta-analysis of 3 large cohort studies confirmed the association of JAK2VF with CVD and with platelet counts and adjusted mean platelet volume (MPV). In mice, 20% or 1.5% Jak2VF CH accelerated arterial thrombosis and increased platelet activation. Megakaryocytes in Jak2VF CH showed elevated proplatelet formation and release, increasing prothrombogenic reticulated platelet counts. Gp1ba-Cre-mediated expression of Jak2VF in platelets (VFGp1ba) increased platelet counts to a similar level as in 20% Jak2VF CH mice while having no effect on leukocyte counts. Like Jak2VF CH mice, VFGp1ba mice showed enhanced platelet activation and accelerated arterial thrombosis. In Jak2VF CH, both Jak2VF and wild-type (WT) platelets showed increased activation, suggesting cross talk between mutant and WT platelets. Jak2VF platelets showed twofold to threefold upregulation of COX-1 and COX-2, particularly in young platelets, with elevated cPLA2 activation and thromboxane A2 production. Compared with controls, conditioned media from activated Jak2VF platelets induced greater activation of WT platelets that was reversed by a thromboxane receptor antagonist. Low-dose aspirin ameliorated carotid artery thrombosis in VFGp1ba and Jak2VF CH mice but not in WT control mice. This study shows accelerated arterial thrombosis and platelet activation in Jak2VF CH with a major role of increased reticulated Jak2VF platelets, which mediate thromboxane cross talk with WT platelets and suggests a potential beneficial effect of aspirin in JAK2VF CH.

The gasdermin family: emerging therapeutic targets in diseases

The gasdermin (GSDM) family has garnered significant attention for its pivotal role in immunity and disease as a key player in pyroptosis. This recently characterized class of pore-forming effector proteins is pivotal in orchestrating processes such as membrane permeabilization, pyroptosis, and the follow-up inflammatory response, which are crucial self-defense mechanisms against irritants and infections. GSDMs have been implicated in a range of diseases including, but not limited to, sepsis, viral infections, and cancer, either through involvement in pyroptosis or independently of this process. The regulation of GSDM-mediated pyroptosis is gaining recognition as a promising therapeutic strategy for the treatment of various diseases. Current strategies for inhibiting GSDMD primarily involve binding to GSDMD, blocking GSDMD cleavage or inhibiting GSDMD-N-terminal (NT) oligomerization, albeit with some off-target effects. In this review, we delve into the cutting-edge understanding of the interplay between GSDMs and pyroptosis, elucidate the activation mechanisms of GSDMs, explore their associations with a range of diseases, and discuss recent advancements and potential strategies for developing GSDMD inhibitors.

Noninvasive Techniques for Tracking Biological Aging of the Cardiovascular System: JACC Family Series

Population aging is one of the most important demographic transformations of our time. Increasing the "health span"-the proportion of life spent in good health-is a global priority. Biological aging comprises molecular and cellular modifications over many years, which culminate in gradual physiological decline across multiple organ systems and predispose to age-related illnesses. Cardiovascular disease is a major cause of ill health and premature death in older people. The rate at which biological aging occurs varies across individuals of the same age and is influenced by a wide range of genetic and environmental exposures. The authors review the hallmarks of biological cardiovascular aging and their capture using imaging and other noninvasive techniques and examine how this information may be used to understand aging trajectories, with the aim of guiding individual- and population-level interventions to promote healthy aging.

High-Dimensional Single-Cell Multimodal Landscape of Human Carotid Atherosclerosis

BACKGROUND

Atherosclerotic plaques are complex tissues composed of a heterogeneous mixture of cells. However, our understanding of the comprehensive transcriptional and phenotypic landscape of the cells within these lesions is limited.

METHODS

To characterize the landscape of human carotid atherosclerosis in greater detail, we combined cellular indexing of transcriptomes and epitopes by sequencing and single-cell RNA sequencing to classify all cell types within lesions (n=21; 13 symptomatic) to achieve a comprehensive multimodal understanding of the cellular identities of atherosclerosis and their association with clinical pathophysiology.

RESULTS

We identified 25 cell populations, each with a unique multiomic signature, including macrophages, T cells, NK (natural killer) cells, mast cells, B cells, plasma cells, neutrophils, dendritic cells, endothelial cells, fibroblasts, and smooth muscle cells (SMCs). Among the macrophages, we identified 2 proinflammatory subsets enriched in IL-1B (interleukin-1B) or C1Q expression, 2 TREM2-positive foam cells (1 expressing inflammatory genes), and subpopulations with a proliferative gene signature and SMC-specific gene signature with fibrotic pathways upregulated. Further characterization revealed various subsets of SMCs and fibroblasts, including SMC-derived foam cells. These foamy SMCs were localized in the deep intima of coronary atherosclerotic lesions. Utilizing cellular indexing of transcriptomes and epitopes by sequencing data, we developed a flow cytometry panel, using cell surface proteins CD29, CD142, and CD90, to isolate SMC-derived cells from lesions. Lastly, we observed reduced proportions of efferocytotic macrophages, classically activated endothelial cells, and contractile and modulated SMC-derived cells, while inflammatory SMCs were enriched in plaques of clinically symptomatic versus asymptomatic patients.

CONCLUSIONS

Our multimodal atlas of cell populations within atherosclerosis provides novel insights into the diversity, phenotype, location, isolation, and clinical relevance of the unique cellular composition of human carotid atherosclerosis. These findings facilitate both the mapping of cardiovascular disease susceptibility loci to specific cell types and the identification of novel molecular and cellular therapeutic targets for the treatment of the disease.

Gasdermin D-Mediated Pyroptosis Promotes the Development of Atherosclerosis

Atherosclerosis is a chronic inflammatory cardiovascular disease with a high-morbidity and mortality rate. An increasing number of studies have addressed the crucial contribution of gasdermin D (GSDMD)-mediated pyroptosis, which is triggered by the inflammasomes to the development of atherosclerosis. However, the underlying mechanism is still unclear. This study aimed to uncover the detailed role of GSDMD in the development of atherosclerosis. An atherosclerotic model was established in Gsdmd-/-/Ldlr-/- mice and Gsdmd+/+/Ldlr-/- mice fed with a high-fat diet. The atherosclerotic lesions, the activation of GSDMD, and the expression level of inflammatory cytokines and chemokines were evaluated. Gsdmd deletion ameliorated the atherosclerotic lesion sizes and the infiltration of immune cells and inflammatory cells in the aortas of mice. Additionally, Gsdmd deletion suppressed the pyroptosis of macrophages and endothelial cells induced by the serum of Ldlr-/- mice fed with a high-fat diet. Furthermore, the formation of neutrophil extracellular traps was also attenuated by knockout of Gsdmd. Bone marrow chimeras confirmed that the genetic deficiency of Gsdmd in both immune cells and intrinsic cells played a role in the promotion of arteriosclerosis. Collectively, our study demonstrated that Gsdmd deletion hindered the pathogenesis of atherosclerosis by inhibiting endothelial cell and macrophage cell death, and the formation of neutrophil extracellular traps.

Cholesterol trafficking to the ER leads to the activation of CaMKII/JNK/NLRP3 and promotes atherosclerosis

The deposition of cholesterol-rich lipoproteins in the arterial wall triggers macrophage inflammatory responses, which promote atherosclerosis. The NLRP3 inflammasome aggravates atherosclerosis; however, cellular mechanisms connecting macrophage cholesterol accumulation to inflammasome activation are poorly understood. We investigated the mechanisms of NLRP3 inflammasome activation in cholesterol-loaded macrophages and in atherosclerosis-prone Ldlr-/- mice with defects in macrophage cholesterol efflux. We found that accumulation of cholesterol in macrophages treated with modified LDL or cholesterol crystals, or in macrophages defective in the cholesterol efflux promoting transporters ABCA1 and ABCG1, leads to activation of NLRP3 inflammasomes as a result of increased cholesterol trafficking from the plasma membrane to the ER, via Aster-B. In turn, the accumulation of cholesterol in the ER activates the inositol triphosphate-3 receptor, CaMKII/JNK, and induces NLRP3 deubiquitylation by BRCC3. An NLRP3 deubiquitylation inhibitor or deficiency of Abro1, an essential scaffolding protein in the BRCC3-containing cytosolic complex, suppressed inflammasome activation, neutrophil extracellular trap formation (NETosis), and atherosclerosis in vivo. These results identify a link between the trafficking of cholesterol to the ER, NLRP3 deubiquitylation, inflammasome activation, and atherosclerosis.

Temporal Single-Cell Sequencing Analysis Reveals That GPNMB-Expressing Macrophages Potentiate Muscle Regeneration

Macrophages play a crucial role in coordinating the skeletal muscle repair response, but their phenotypic diversity and the transition of specialized subsets to resolution-phase macrophages remain poorly understood. To address this issue, we induced injury and performed single-cell RNA sequencing on individual cells in skeletal muscle at different time points. Our analysis revealed a distinct macrophage subset that expressed high levels of Gpnmb and that coexpressed critical factors involved in macrophage-mediated muscle regeneration, including Igf1, Mertk, and Nr1h3. Gpnmb gene knockout inhibited macrophage-mediated efferocytosis and impaired skeletal muscle regeneration. Functional studies demonstrated that GPNMB acts directly on muscle cells in vitro and improves muscle regeneration in vivo. These findings provide a comprehensive transcriptomic atlas of macrophages during muscle injury, highlighting the key role of the GPNMB macrophage subset in regenerative processes. Targeting GPNMB signaling in macrophages could have therapeutic potential for restoring skeletal muscle integrity and homeostasis.

Ferroptosis: a potential target for the treatment of atherosclerosis

Atherosclerosis (AS), the main contributor to acute cardiovascular events, such as myocardial infarction and ischemic stroke, is characterized by necrotic core formation and plaque instability induced by cell death. The mechanisms of cell death in AS have recently been identified and elucidated. Ferroptosis, a novel iron-dependent form of cell death, has been proven to participate in atherosclerotic progression by increasing endothelial reactive oxygen species (ROS) levels and lipid peroxidation. Furthermore, accumulated intracellular iron activates various signaling pathways or risk factors for AS, such as abnormal lipid metabolism, oxidative stress, and inflammation, which can eventually lead to the disordered function of macrophages, vascular smooth muscle cells, and vascular endothelial cells. However, the molecular pathways through which ferroptosis affects AS development and progression are not entirely understood. This review systematically summarizes the interactions between AS and ferroptosis and provides a feasible approach for inhibiting AS progression from the perspective of ferroptosis.

Clonal haematopoiesis of indeterminate potential predicts incident cardiac arrhythmias

BACKGROUND AND AIMS

Clonal haematopoiesis of indeterminate potential (CHIP), the age-related expansion of blood cells with preleukemic mutations, is associated with atherosclerotic cardiovascular disease and heart failure. This study aimed to test the association of CHIP with new-onset arrhythmias.

METHODS

UK Biobank participants without prevalent arrhythmias were included. Co-primary study outcomes were supraventricular arrhythmias, bradyarrhythmias, and ventricular arrhythmias. Secondary outcomes were cardiac arrest, atrial fibrillation, and any arrhythmia. Associations of any CHIP [variant allele fraction (VAF) ≥ 2%], large CHIP (VAF ≥10%), and gene-specific CHIP subtypes with incident arrhythmias were evaluated using multivariable-adjusted Cox regression. Associations of CHIP with myocardial interstitial fibrosis [T1 measured using cardiac magnetic resonance (CMR)] were also tested.

RESULTS

This study included 410 702 participants [CHIP: n = 13 892 (3.4%); large CHIP: n = 9191 (2.2%)]. Any and large CHIP were associated with multi-variable-adjusted hazard ratios of 1.11 [95% confidence interval (CI) 1.04-1.18; P = .001] and 1.13 (95% CI 1.05-1.22; P = .001) for supraventricular arrhythmias, 1.09 (95% CI 1.01-1.19; P = .031) and 1.13 (95% CI 1.03-1.25; P = .011) for bradyarrhythmias, and 1.16 (95% CI, 1.00-1.34; P = .049) and 1.22 (95% CI 1.03-1.45; P = .021) for ventricular arrhythmias, respectively. Associations were independent of coronary artery disease and heart failure. Associations were also heterogeneous across arrhythmia subtypes and strongest for cardiac arrest. Gene-specific analyses revealed an increased risk of arrhythmias across driver genes other than DNMT3A. Large CHIP was associated with 1.31-fold odds (95% CI 1.07-1.59; P = .009) of being in the top quintile of myocardial fibrosis by CMR.

CONCLUSIONS

CHIP may represent a novel risk factor for incident arrhythmias, indicating a potential target for modulation towards arrhythmia prevention and treatment.

"How to Release or Not Release, That Is the Question." A Review of Interleukin-1 Cellular Release Mechanisms in Vascular Inflammation

Cardiovascular disease remains the leading cause of death worldwide, characterized by atherosclerotic activity within large and medium-sized arteries. Inflammation has been shown to be a primary driver of atherosclerotic plaque formation, with interleukin-1 (IL-1) having a principal role. This review focuses on the current state of knowledge of molecular mechanisms of IL-1 release from cells in atherosclerotic plaques. A more in-depth understanding of the process of IL-1's release into the vascular environment is necessary for the treatment of inflammatory disease processes, as the current selection of medicines being used primarily target IL-1 after it has been released. IL-1 is secreted by several heterogenous mechanisms, some of which are cell type-specific and could provide further specialized targets for therapeutic intervention. A major unmet challenge is to understand the mechanism before and leading to IL-1 release, especially by cells in atherosclerotic plaques, including endothelial cells, vascular smooth muscle cells, and macrophages. Data so far indicate a heterogeneity of IL-1 release mechanisms that vary according to cell type and are stimulus-dependent. Unraveling this complexity may reveal new targets to block excess vascular inflammation.

[Heart and blood: clonal hematopoiesis]

Cardiovascular diseases are among the leading causes of death worldwide, with well-known modifiable risk factors, such as smoking, overweight, lipid metabolism disorders, lack of physical activity and high blood pressure playing a significant role. Recent studies have now identified "clonal hematopoiesis" as a novel blood-based risk factor. Clonal hematopoiesis arises from mutations in hematopoietic stem cells, which lead to the expansion of mutated blood cells. Mutated cell clones can be detected in over 40% of individuals over 50 years old, with more than 15% of those over 90 years old harboring large clones. Surprisingly, mutated cells predispose to the development of leukemia only to a minor extent, leading to the term clonal hematopoiesis of indeterminate potential (CHIP); however, it has been shown that CHIP is associated with an increased risk of cardiovascular diseases. Individuals with CHIP-associated gene mutations have an elevated risk of atherosclerotic vascular diseases, stroke and thrombosis. Patients with heart failure with reduced ejection fraction (HFrEF), whether of ischemic or non-ischemic origin and patients with heart failure with preserved ejection fraction (HFpEF) exhibit an increased number of mutated cells in the blood. The presence of CHIP mutations is linked to a poorer prognosis in patients with existing cardiovascular diseases. Future research should aim at a better understanding of the specific effects of different mutations, clone sizes and combinations to develop personalized therapeutic approaches. Various anti-inflammatory therapeutic drugs are available, which can be tested in controlled studies.

Somatic and Germline Variants and Coronary Heart Disease in a Chinese Population

Importance

The genetic basis of coronary heart disease (CHD) has expanded from a germline to somatic genome, including clonal hematopoiesis of indeterminate potential (CHIP). How CHIP confers CHD risk in East Asian individuals, especially those with small clones (variant allele fraction [VAF] 0.5%-2%) and different genetic backgrounds, was completely unknown.

Objective

To investigate the CHIP profile in a general Chinese cohort by deep sequencing and further explore the association between CHIP and incident CHD considering germline predisposition.

Design, Setting, and Participants

This cohort study used data from 3 prospective cohorts in the project Prediction for Atherosclerotic Cardiovascular Disease Risk in China. Participants without cardiovascular disease or cancer at baseline were enrolled in 2001 and 2008 and had a median follow-up of 12.17 years extending into 2021.

Exposures

CHIP mutations were detected by targeted sequencing (mean depth, 916×). A predefined CHD polygenic risk score (PRS) comprising 531 variants was used to evaluate germline predisposition.

Main Outcomes and Measures

The main outcome was first incident CHD.

Results

Among 6181 participants, the median (IQR) age was 53.83 years (45.35-62.39 years); 3082 participants (49.9%) were female, and 3099 (50.1%) were male. A total of 1100 individuals (17.80%) harbored 1372 CHIP mutations at baseline. CHIP was independently associated with incident CHD (hazard ratio [HR], 1.42; 95% CI, 1.18-1.72; P = 2.82 × 10-4) and presented a risk gradient with increasing VAF (P = 3.98 × 10-3 for trend). Notably, individuals with small clones, nearly half of CHIP carriers, also demonstrated a higher CHD risk compared with non-CHIP carriers (HR, 1.33; 95% CI, 1.02-1.74; P = .03) and were 4 years younger than those with VAF of 2% or greater (median age, 58.52 vs 62.70 years). Heightened CHD risk was not observed among CHIP carriers with low PRS (HR, 1.02; 95% CI, 0.64-1.64; P = .92), while high PRS and CHIP jointly contributed a 2.23-fold increase in risk (95% CI, 1.51-3.29; P = 6.29 × 10-5) compared with non-CHIP carriers with low PRS. Interestingly, the diversity in CHIP-related CHD risk within each PRS group was substantially diminished when removing variants in the inflammatory pathway from the PRS.

Conclusions

This study revealed that elevated CHD risk attributed to CHIP was nonnegligible even for small clones. Inflammation genes involved in CHD could aggravate or abrogate CHIP-related CHD risk.

Targeting the JAK2/STAT3 signaling pathway with natural plants and phytochemical ingredients: A novel therapeutic method for combatting cardiovascular diseases

The aim of this article is to introduce the roles and mechanisms of the JAK2/STAT3 pathway in various cardiovascular diseases, such as myocardial fibrosis, cardiac hypertrophy, atherosclerosis, myocardial infarction, and myocardial ischemiareperfusion. In addition, the effects of phytochemical ingredients and different natural plants, mainly traditional Chinese medicines, on the regulation of different cardiovascular diseases via the JAK2/STAT3 pathway are discussed. Surprisingly, the JAK2 pathway has dual roles in different cardiovascular diseases. Future research should focus on the dual regulatory effects of different phytochemical ingredients and natural plants on JAK2 to pave the way for their use in clinical trials.

Clonal hematopoiesis of indeterminate potential is associated with acute kidney injury

Age is a predominant risk factor for acute kidney injury (AKI), yet the biological mechanisms underlying this risk are largely unknown. Clonal hematopoiesis of indeterminate potential (CHIP) confers increased risk for several chronic diseases associated with aging. Here we sought to test whether CHIP increases the risk of AKI. In three population-based epidemiology cohorts, we found that CHIP was associated with a greater risk of incident AKI, which was more pronounced in patients with AKI requiring dialysis and in individuals with somatic mutations in genes other than DNMT3A, including mutations in TET2 and JAK2. Mendelian randomization analyses supported a causal role for CHIP in promoting AKI. Non-DNMT3A-CHIP was also associated with a nonresolving pattern of injury in patients with AKI. To gain mechanistic insight, we evaluated the role of Tet2-CHIP and Jak2V617F-CHIP in two mouse models of AKI. In both models, CHIP was associated with more severe AKI, greater renal proinflammatory macrophage infiltration and greater post-AKI kidney fibrosis. In summary, this work establishes CHIP as a genetic mechanism conferring impaired kidney function recovery after AKI via an aberrant inflammatory response mediated by renal macrophages.

Clonal haematopoiesis, ageing and kidney disease

Clonal haematopoiesis of indeterminate potential (CHIP) is a preclinical condition wherein a sizeable proportion of an individual's circulating blood cells are derived from a single mutated haematopoietic stem cell. CHIP occurs frequently with ageing - more than 10% of individuals over 65 years of age are affected - and is associated with an increased risk of disease across several organ systems and premature death. Emerging evidence suggests that CHIP has a role in kidney health, including associations with predisposition to acute kidney injury, impaired recovery from acute kidney injury and kidney function decline, both in the general population and among those with chronic kidney disease. Beyond its direct effect on the kidney, CHIP elevates the susceptibility of individuals to various conditions that can detrimentally affect the kidneys, including cardiovascular disease, obesity and insulin resistance, liver disease, gout, osteoporosis and certain autoimmune diseases. Aberrant pro-inflammatory signalling, telomere attrition and epigenetic ageing are potential causal pathophysiological pathways and mediators that underlie CHIP-related disease risk. Experimental animal models have shown that inhibition of inflammatory cytokine signalling can ameliorate many of the pathological effects of CHIP, and assessment of the efficacy and safety of this class of medications for human CHIP-associated pathology is ongoing.

Nucleic acid-induced inflammation on hematopoietic stem cells

Hematopoiesis, the process of generating blood cells, starts during development with the primitive, pro-definitive, and definitive hematopoietic waves. The first two waves will generate erythrocytes and myeloid cells, although the definitive wave will give rise to hematopoietic stem cells (HSCs) that are multipotent and can produce most of the blood cells in an adult. Although HSCs are highly proliferative during development, during adulthood they remain quiescent in the bone marrow. Inflammatory signaling in the form of interferons, interleukins, tumor necrosis factors, and others is well-established to influence both developmental and adult hematopoiesis. Here we discuss the role of specific inflammatory pathways that are induced by sensing nucleic acids. We discuss the role of RNA-sensing members of the Toll-like, Rig-I-like, nucleotide-binding oligomerization domain (NOD)-like, and AIM2-like protein kinase receptors and the DNA-sensing receptors, DEAD-Box helicase 41 (DDX41) and cGAS. The main downstream pathways of these receptors are discussed, as well as their influence on developmental and adult hematopoiesis, including hematopoietic pathologies.

Novel Perspectives in Chronic Kidney Disease-Specific Cardiovascular Disease

Chronic kidney disease (CKD) affects > 10% of the global adult population and significantly increases the risk of cardiovascular disease (CVD), which remains the leading cause of death in this population. The development and progression of CVD-compared to the general population-is premature and accelerated, manifesting as coronary artery disease, heart failure, arrhythmias, and sudden cardiac death. CKD and CV disease combine to cause multimorbid cardiorenal syndrome (CRS) due to contributions from shared risk factors, including systolic hypertension, diabetes mellitus, obesity, and dyslipidemia. Additional neurohormonal activation, innate immunity, and inflammation contribute to progressive cardiac and renal deterioration, reflecting the strong bidirectional interaction between these organ systems. A shared molecular pathophysiology-including inflammation, oxidative stress, senescence, and hemodynamic fluctuations characterise all types of CRS. This review highlights the evolving paradigm and recent advances in our understanding of the molecular biology of CRS, outlining the potential for disease-specific therapies and biomarker disease detection.

Bone marrow inflammatory memory in cardiometabolic disease and inflammatory comorbidities

Cardiometabolic disorders are chief causes of morbidity and mortality, with chronic inflammation playing a crucial role in their pathogenesis. The release of differentiated myeloid cells with elevated pro-inflammatory potential, as a result of maladaptively trained myelopoiesis may be a crucial factor for the perpetuation of inflammation. Several cardiovascular risk factors, including sedentary lifestyle, unhealthy diet, hypercholesterolemia, and hyperglycemia, may modulate bone marrow hematopoietic progenitors, causing sustained functional changes that favour chronic metabolic and vascular inflammation. In the present review, we summarize recent studies that support the function of long-term inflammatory memory in progenitors of the bone marrow for the development and progression of cardiometabolic disease and related inflammatory comorbidities, including periodontitis and arthritis. We also discuss how maladaptive myelopoiesis associated with the presence of mutated hematopoietic clones, as present in clonal hematopoiesis, may accelerate atherosclerosis via increased inflammation.

Association between periodontitis and inflammatory comorbidities: The common role of innate immune cells, underlying mechanisms and therapeutic targets

Periodontitis, which is related to various systemic diseases, is a chronic inflammatory disease caused by periodontal dysbiosis of the microbiota. Multiple factors can influence the interaction of periodontitis and associated inflammatory disorders, among which host immunity is an important contributor to this interaction. Innate immunity can be activated aberrantly because of the systemic inflammation induced by periodontitis. This aberrant activation not only exacerbates periodontal tissue damage but also impairs systemic health, triggering or aggravating inflammatory comorbidities. Therefore, innate immunity is a potential therapeutic target for periodontitis and associated inflammatory comorbidities. This review delineates analogous aberrations of innate immune cells in periodontitis and comorbid conditions such as atherosclerosis, diabetes, obesity, and rheumatoid arthritis. The mechanisms behind these changes in innate immune cells are discussed, including trained immunity and clonal hematopoiesis of indeterminate potential (CHIP), which can mediate the abnormal activation and myeloid-biased differentiation of hematopoietic stem and progenitor cells. Besides, the expansion of myeloid-derived suppressor cells (MDSCs), which have immunosuppressive and osteolytic effects on peripheral tissues, also contributes to the interaction between periodontitis and its inflammatory comorbidities. The potential treatment targets for relieving the risk of both periodontitis and systemic conditions are also elucidated, such as the modulation of innate immunity cells and mediators, the regulation of trained immunity and CHIP, as well as the inhibition of MDSCs' expansion.

Single-cell RNA Sequencing (scRNA-seq): Advances and Challenges for Cardiovascular Diseases (CVDs)

Implementing Single-cell RNA sequencing (scRNA-seq) has significantly enhanced our comprehension of cardiovascular diseases (CVDs), providing new opportunities to strengthen the prevention of CVDs progression. Cardiovascular diseases continue to be the primary cause of death worldwide. Improving treatment strategies and patient risk assessment requires a deeper understanding of the fundamental mechanisms underlying these disorders. The advanced and widespread use of Single-cell RNA sequencing enables a comprehensive investigation of the complex cellular makeup of the heart, surpassing essential descriptive aspects. This enhances our understanding of disease causes and directs functional research. The significant advancement in understanding cellular phenotypes has enhanced the study of fundamental cardiovascular science. scRNA-seq enables the identification of discrete cellular subgroups, unveiling previously unknown cell types in the heart and vascular systems that may have relevance to different disease pathologies. Moreover, scRNA-seq has revealed significant heterogeneity in phenotypes among distinct cell subtypes. Finally, we will examine current and upcoming scRNA-seq studies about various aspects of the cardiovascular system, assessing their potential impact on our understanding of the cardiovascular system and offering insight into how these technologies may revolutionise the diagnosis and treatment of cardiac conditions.

Clonal hematopoiesis and autoimmunity

Clonal hematopoiesis (CH) has been associated with aging, occurring in about 10% of individuals aged >70 years, and immune dysfunction. Aged hematopoietic stem and progenitor cells exhibit pathological changes in immune function and activation of inflammatory pathways. CH clones commonly harbor a loss of function mutation in DNMT3A or TET2, which causes increased expression of inflammatory signaling genes, a proposed mechanism connected to CH and the development of age-related diseases. Additionally, inflammation may stress the hematopoietic compartment, driving the expansion of mutant clones. While the epidemiologic overlap between CH, hematologic malignancies, and atherosclerotic cardiovascular diseases has been reported, the mechanisms linking these concepts are largely unknown and merit much further investigation. Here, we review studies highlighting the interplay between CH, inflamm-aging, the immune system, and the prevalence of CH in autoimmune diseases.

MCL attenuates atherosclerosis by suppressing macrophage ferroptosis via targeting KEAP1/NRF2 interaction

BACKGROUND

Micheliolide (MCL), which is the active metabolite of parthenolide, has demonstrated promising clinical application potential. However, the effects and underlying mechanisms of MCL on atherosclerosis are still unclear.

METHOD

ApoE-/- mice were fed with high fat diet, with or without MCL oral administration, then the plaque area, lipid deposition and collagen content were determined. In vitro, MCL was used to pretreat macrophages combined by ox-LDL, the levels of ferroptosis related proteins, NRF2 activation, mitochondrial function and oxidative stress were detected.

RESULTS

MCL administration significantly attenuated atherosclerotic plaque progress, which characteristics with decreased plaque area, less lipid deposition and increased collagen. Compared with HD group, the level of GPX4 and xCT in atherosclerotic root macrophages were increased in MCL group obviously. In vitro experiment demonstrated that MCL increased GPX4 and xCT level, improved mitochondrial function, attenuated oxidative stress and inhibited lipid peroxidation to suppress macrophage ferroptosis induced with ox-LDL. Moreover, MCL inhibited KEAP1/NRF2 complex formation and enhanced NRF2 nucleus translocation, while the protective effect of MCL on macrophage ferroptosis was abolished by NRF2 inhibition. Additionally, molecular docking suggests that MCL may bind to the Arg483 site of KEAP1, which also contributes to KEAP1/NRF2 binding. Furthermore, Transfection Arg483 (KEAP1-R483S) mutant plasmid can abrogate the anti-ferroptosis and anti-oxidative effects of MC in macrophages. KEAP1-R483S mutation also limited the protective effect of MCL on atherosclerosis progress and macrophage ferroptosis in ApoE-/- mice.

CONCLUSION

MCL suppressed atherosclerosis by inhibiting macrophage ferroptosis via activating NRF2 pathway, the related mechanism is through binding to the Arg483 site of KEAP1 competitively.

Lipoprotein(a) is associated with DNA damage in patients with heterozygous familial hypercholesterolemia

Heterozygous familial hypercholesterolemia (HeFH) is a common autosomal-dominant inherited disorder associated with atherosclerotic cardiovascular disease (ASCVD). HeFH subjects have a higher lipoprotein(a), i.e. Lp(a), concentration than the general population. Patients with FH are exposed to elevated levels of LDL from birth and ox-LDL may induce other oxidation pathways. The aim of the study was to determine the levels of markers of oxidative stress and DNA damage in patients with HeFH and describe the effect of Lp(a) on the resulting damage. Higher DNA damage was identified in patients with HeFH compared to the normolipidemic ones, and ASCVD was associated with greater damage. Oxidative stress markers were elevated in HeFH patients; however, only ox-LDL was higher in the ASCVD group and its level correlated with DNA damage. A positive correlation was found between DNA damage and Lp(a) concentration in the HeFH patients. Higher levels of Lp(a) were associated with greater DNA damage, especially in patients with HeFH and ASCVD. In HeFH patients, the optimal Lp(a) cut-off point associated with ASCVD is > 23.45 nmol/L, i.e. much lower than for the general population; however this cut-off point needs validation in a larger group of HeFH patients.

Epigenetic modification of TWIST1 in macrophages promotes hypertension-induced atherosclerotic plaque instability

It is accepted that hypertension is a major, independent risk factor for atherosclerotic cardiovascular ischemic events, which are mainly attributed to the formation of unstable, vulnerable atherosclerotic lesions. But the mechanisms by which hypertension aggravates atherosclerosis (AS) through increased macrophage recruitment are unknown. It has been reported that TWIST1 can regulate the shear stress of blood flow in endothelial cells to promote the development of atherosclerosis, but the function of TWIST1 in macrophage recruitment during hypertension remains undefined. Here, the roles of TWIST1 in macrophage activation during N w -nitro-l-arginine-methyl ester (L-NAME; NO-synthase (NOS) inhibitor)-induced hypertension were investigated in ApoE-/- mice fed a high-fat diet (HFD) and RAW264.7 cells treated with oxidized low-density lipoprotein(ox-LDL). Oil Red O staining and hematoxylin and eosin staining were adopted to analyze atherosclerotic lesions and plaque instability. Chromatin immunoprecipitation (ChIP)-PCR was used to explore whether Lysine-specific histone demethylase 1A (LSD1/KDM1A) and Variegated suppressor 3-9 homolog 1 (SUV39H1) could regulate histone modification of the TWIST1 promoter. We reported that L-NAME increased the expression of TWIST1 in the aortic tissues of ApoE-/- mice fed a high-fat diet (HFD) and RAW264.7 cells treated with ox-LDL. TWIST1 accelerated the development of an unstable atherosclerotic phenotype by promoting macrophage activation, inflammatory factor secretion, macrophage polarization, and lipid phagocytosis. Moreover, we found that H3K9me2 and H3K9me3 in the TWIST1 promoter could be coregulated by LSD1 and SUV39H1, and this process was modulated by CK2α. Taken together, these results revealed that TWIST1 in macrophages is a critical factor that mediates foam cell formation and enhances atherosclerotic plaque vulnerability during hypertension, and targeting TWIST1 may be a promising new therapeutic approach for delaying the progression of AS in hypertension.

Control of Cell Death in Health and Disease

Apoptosis, necroptosis, and pyroptosis are genetically programmed cell death mechanisms that eliminate obsolete, damaged, infected, and self-reactive cells. Apoptosis fragments cells in a manner that limits immune cell activation, whereas the lytic death programs of necroptosis and pyroptosis release proinflammatory intracellular contents. Apoptosis fine-tunes tissue architecture during mammalian development, promotes tissue homeostasis, and is crucial for averting cancer and autoimmunity. All three cell death mechanisms are deployed to thwart the spread of pathogens. Disabling regulators of cell death signaling in mice has revealed how excessive cell death can fuel acute or chronic inflammation. Here we review strategies for modulating cell death in the context of disease. For example, BCL-2 inhibitor venetoclax, an inducer of apoptosis, is approved for the treatment of certain hematologic malignancies. By contrast, inhibition of RIPK1, NLRP3, GSDMD, or NINJ1 to limit proinflammatory cell death and/or the release of large proinflammatory molecules from dying cells may benefit patients with inflammatory diseases.

Clonal hematopoiesis of indeterminate potential-associated non-small cell lung cancer risk is potentiated by small particulate matter air pollution among non-smokers: a novel somatic variant-environment interaction

Small particulate matter air pollution (PM 2.5 ) is a recognized driver of non-small cell lung cancer (NSCLC) among non-smoking individuals. Inhaled PM 2.5 recruits pro-inflammatory macrophages to the air-lung interface, which promotes malignant lung epithelial cell growth and progression to overt cancer. We sought to determine whether clonal hematopoiesis of indeterminate potential (CHIP), a common age-related condition characterized by hyperinflammatory macrophages, exacerbates PM 2.5 -associated NSCLC in non-smokers using genetic, environmental, and phenotypic data from 413,901 individuals in the UK Biobank. Among non-smokers, PM 2.5 is not associated with NSCLC and not associated with prevalence of CHIP, but CHIP is associated with a doubling of NSCLC risk (hazard ratio (HR) 2.01, 95% confidence interval (CI): 1.34-3.00). Moreover, CHIP-associated NSCLC risk is exacerbated in the setting of above-median PM 2.5 levels (HR 2.70, 95% CI: 1.60-4.55). PM 2.5 × CHIP is also associated with significantly greater markers of systemic inflammation (CRP, IL-6, and IL-1β) than expected. Altogether, these results suggest CHIP and PM 2.5 form a novel gene × environment interaction promoting NSCLC tumorigenesis in non-smokers.

Advances in crosstalk among innate immune pathways activated by mitochondrial DNA

Mitochondria are not only the power plant for intracellular oxidative phosphorylation and ATP synthesis, but also involved in cell proliferation, differentiation, signaling and apoptosis. Recent studies have shown that mitochondria play an important role in other pathophysiological functions in addition to cellular energy metabolism. Mitochondria release mitochondrial DNA (mtDNA) as a damage-associated molecular pattern (DAMP) to activate Toll-like receptor 9 (TLR9), NOD-, LRR-, and pyrin domain-containing 3 (NLRP3) inflammasome and cyclic GMP-AMP synthase (cGAS)-stimulator of interferon genes (STING) innate immune signaling pathways against foreign pathogenic microorganisms. The innate immune response not only promotes antimicrobial immune defense and regulates antiviral signaling, but their overactivation also induces the onset and progression of inflammatory diseases. In this paper, we review the role of mtDNA in the activation of innate immune signaling pathways and the crosstalk among innate immune signaling pathways activated by mtDNA, providing clues for the study of inflammatory diseases caused by mtDNA cytoplasmic translocation.

A High-Protein Diet Promotes Atrial Arrhythmogenesis via Absent-in-Melanoma 2 Inflammasome

High-protein diets (HPDs) offer health benefits, such as weight management and improved metabolic profiles. The effects of HPD on cardiac arrhythmogenesis remain unclear. Atrial fibrillation (AF), the most common arrhythmia, is associated with inflammasome activation. The role of the Absent-in-Melanoma 2 (AIM2) inflammasome in AF pathogenesis remains unexplored. In this study, we discovered that HPD increased susceptibility to AF. To demonstrate the involvement of AIM2 signaling in the pathogenesis of HPD-induced AF, wildtype (WT) and Aim2-/- mice were fed normal-chow (NC) and HPD, respectively. Four weeks later, inflammasome activity was upregulated in the atria of WT-HPD mice, but not in the Aim2-/--HPD mice. The increased AF vulnerability in WT-HPD mice was associated with abnormal sarcoplasmic reticulum (SR) Ca2+-release events in atrial myocytes. HPD increased the cytoplasmic double-strand (ds) DNA level, causing AIM2 activation. Genetic inhibition of AIM2 in Aim2-/- mice reduced susceptibility to AF, cytoplasmic dsDNA level, mitochondrial ROS production, and abnormal SR Ca2+-release in atrial myocytes. These data suggest that HPD creates a substrate conducive to AF development by activating the AIM2-inflammasome, which is associated with mitochondrial oxidative stress along with proarrhythmic SR Ca2+-release. Our data imply that targeting the AIM2 inflammasome might constitute a novel anti-AF strategy in certain patient subpopulations.

Exploring the therapeutic potential of Sirt6-enriched adipose stem cell-derived exosomes in myocardial ischemia-reperfusion injury: unfolding new epigenetic frontiers

BACKGROUND

The management of myocardial ischemia-reperfusion injury (MIRI) presents continuous therapeutic challenges. NAD-dependent deacetylase Sirtuin 6 (Sirt6) plays distinct roles in various disease contexts and is hence investigated for potential therapeutic applications for MIRI. This study aimed to examine the impact of Sirt6-overexpressing exosomes derived from adipose stem cells (S-ASC-Exo) on MIRI, focusing on their influence on AIM2-pyroptosis and mitophagy processes. The sirtuin family of proteins, particularly Sirtuin 6 (Sirt6), play a pivotal role in these processes. This study aimed to explore the potential therapeutic effects of Sirt6-enriched exosomes derived from adipose stem cells (S-ASC-Exo) on regulating MIRI.

RESULTS

Bioinformatic analysis revealed a significant downregulation of Sirt6 in MIRI subjected to control group, causing a consequential increase in mitophagy and pyroptosis regulator expressions. Therefore, our study revealed that Sirt6-enriched exosomes influenced the progression of MIRI through the regulation of target proteins AIM2 and GSDMD, associated with pyroptosis, and p62 and Beclin-1, related to mitophagy. The introduction of S-ASC-Exo inhibited AIM2-pyroptosis while enhancing mitophagy. Consequently, this led to a significant reduction of GSDMD cleavage and pyroptosis in endothelial cells, catalyzing a deceleration in the progression of atherosclerosis. Extensive in vivo and in vitro assays were performed to validate the expressions of these specific genes and proteins, which affirmed the dynamic modulation by Sirt6-enriched exosomes. Furthermore, treatment with S-ASC-Exo drastically ameliorated cardiac functions and limited infarct size, underlining their cardioprotective attributes.

CONCLUSIONS

Our study underscores the potential therapeutic role of Sirt6-enriched exosomes in managing MIRI. We demonstrated their profound cardioprotective effect, evident in the enhanced cardiac function and attenuated tissue damage, through the strategic modulation of AIM2-pyroptosis and mitophagy. Given the intricate interplay between Sirt6 and the aforementioned processes, a comprehensive understanding of these pathways is essential to fully exploit the therapeutic potential of Sirt6. Altogether, our findings indicate the promise of Sirt6-enriched exosomes as a novel therapeutic strategy in treating ischemia-reperfusion injuries and cardiovascular diseases at large. Future research needs to underscore optimizing the balance of mitophagy during myocardial ischemia to avoid potential loss of normal myocytes.

Clonal Expansion in Cardiovascular Pathology

Clonal expansion refers to the proliferation and selection of advantageous "clones" that are better suited for survival in a Darwinian manner. In recent years, we have greatly enhanced our understanding of cell clonality in the cardiovascular context. However, our knowledge of the underlying mechanisms behind this clonal selection is still severely limited. There is a transpiring pattern of clonal expansion of smooth muscle cells and endothelial cells-and, in some cases, macrophages-in numerous cardiovascular diseases irrespective of their differing microenvironments. These findings indirectly suggest the possible existence of stem-like vascular cells which are primed to respond during disease. Subsequent clones may undergo further phenotypic changes to adopt either protective or detrimental roles. By investigating these clone-forming vascular cells, we may be able to harness this inherent clonal nature for future therapeutic intervention. This review comprehensively discusses what is currently known about clonal expansion across the cardiovascular field. Comparisons of the clonal nature of vascular cells in atherosclerosis (including clonal hematopoiesis of indeterminate potential), pulmonary hypertension, aneurysm, blood vessel injury, ischemia- and tumor-induced angiogenesis, and cerebral cavernous malformations are evaluated. Finally, we discuss the potential clinical implications of these findings and propose that proper understanding and specific targeting of these clonal cells may provide unique therapeutic options for the treatment of these cardiovascular conditions.

Protein Tyrosine Phosphatase SHP2 in Macrophages Acts as an Antiatherosclerotic Regulator in Mice

BACKGROUND

Macrophages have versatile roles in atherosclerosis. SHP2 (Src homology 2 containing protein tyrosine phosphatase 2) has been demonstrated to play a critical role in regulating macrophage activation. However, the mechanism of SHP2 regulation of macrophage function in an atherosclerotic microenvironment remains unknown.

METHODS

APOE (apolipoprotein E) or LDLR (low-density lipoprotein receptor) null mice treated with SHP099 were fed a Western diet for 8 weeks, while Shp2MKO:ApoE-/- or Shp2MKO:Ldlr-/- mice and exo-AAV8-SHP2E76K/ApoE-/- mice were fed a Western diet for 12 weeks. In vitro, levels of proinflammatory factors and phagocytic function were then studied in mouse peritoneal macrophages. RNA sequencing was used to identify PPARγ (peroxisome proliferative activated receptor γ) as the key downstream molecule. A PPARγ agonist was used to rescue the phenotypes observed in SHP2-deleted mice.

RESULTS

Pharmacological inhibition and selective deletion in macrophages of SHP2 aggravated atherosclerosis in APOE and LDLR null mice with increased plaque macrophages and apoptotic cells. In vitro, SHP2 deficiency in APOE and LDLR null macrophages enhanced proinflammatory polarization and its efferocytosis was dramatically impaired. Conversely, the expression of gain-of-function mutation of SHP2 in mouse macrophages reduced atherosclerosis. The SHP2 agonist lovastatin repressesed macrophage inflammatory activation and enhanced efferocytosis. Mechanistically, RNA sequencing analysis identified PPARγ as a key downstream transcription factor. PPARγ was decreased in macrophages upon SHP2 deletion and inhibition. Importantly, PPARγ agonist decreased atherosclerosis in SHP2 knockout mice, restored efferocytotic defects, and reduced inflammatory activation in SHP2 deleted macrophages. PPARγ was decreased by the ubiquitin-mediated degradation upon SHP2 inhibition or deletion. Finally, we found that SHP2 was downregulated in atherosclerotic vessels.

CONCLUSIONS

Overall, SHP2 in macrophages was found to act as an antiatherosclerotic regulator by stabilizing PPARγ in APOE/LDLR null mice.

miR-223-3p Prevents Necroptotic Macrophage Death by Targeting Ripk3 in a Negative Feedback Loop and Consequently Ameliorates Advanced Atherosclerosis

BACKGROUND

The formation of large necrotic cores results in vulnerable atherosclerotic plaques, which can lead to severe cardiovascular diseases. However, the specific regulatory mechanisms underlying the development of necrotic cores remain unclear.

METHODS

To evaluate how the modes of lesional cell death are reprogrammed during the development of atherosclerosis, the expression levels of key proteins that are involved in the necroptotic, apoptotic, and pyroptotic pathways were compared between different stages of plaques in humans and mice. Luciferase assays and loss-of-function studies were performed to identify the microRNA-mediated regulatory mechanism that protects foamy macrophages from necroptotic cell death. The role of this mechanism in atherosclerosis was determined by using a knockout mouse model with perivascular drug administration and tail vein injection of microRNA inhibitors in Apoe-/- mice.

RESULTS

Here, we demonstrate that the necroptotic, rather than the apoptotic or pyroptotic, pathway is more activated in advanced unstable plaques compared with stable plaques in both humans and mice, which closely correlates with necrotic core formation. The upregulated expression of Ripk3 (receptor-interacting protein kinase 3) promotes the C/EBPβ (CCAAT/enhancer binding protein beta)-dependent transcription of the microRNA miR-223-3p, which conversely inhibits Ripk3 expression and forms a negative feedback loop to regulate the necroptosis of foamy macrophages. The knockout of the Mir223 gene in bone marrow cells accelerates atherosclerosis in Apoe-/- mice, but this effect can be rescued by Ripk3 deficiency or treatment with the necroptosis inhibitors necrostatin-1 and GSK-872. Like the Mir223 knockout, treating Apoe-/- mice with miR-223-3p inhibitors increases atherosclerosis.

CONCLUSIONS

Our study suggests that miR-223-3p expression in macrophages protects against atherosclerotic plaque rupture by limiting the formation of necrotic cores, thus providing a potential microRNA therapeutic candidate for atherosclerosis.

Drugging the NLRP3 inflammasome: from signalling mechanisms to therapeutic targets

Diseases associated with chronic inflammation constitute a major health burden across the world. As central instigators of the inflammatory response to infection and tissue damage, inflammasomes - and the NACHT, LRR and PYD domain-containing protein 3 (NLRP3) inflammasome in particular - have emerged as key regulators in diverse rheumatic, metabolic and neurodegenerative diseases. Similarly to other inflammasome sensors, NLRP3 assembles a cytosolic innate immune complex that activates the cysteine protease caspase-1, which in turn cleaves gasdermin D (GSDMD) to induce pyroptosis, a regulated mode of lytic cell death. Pyroptosis is highly inflammatory, partly because of the concomitant extracellular release of the inflammasome-dependent cytokines IL-1β and IL-18 along with a myriad of additional danger signals and intracellular antigens. Here, we discuss how NLRP3 and downstream inflammasome effectors such as GSDMD, apoptosis-associated speck-like protein containing a CARD (ASC) and nerve injury-induced protein 1 (NINJ1) have gained significant traction as therapeutic targets. We highlight the recent progress in developing small-molecule and biologic inhibitors that are advancing into the clinic and serving to harness the broad therapeutic potential of modulating the NLRP3 inflammasome.

Suppression of IL-1β promotes beneficial accumulation of fibroblast-like cells in atherosclerotic plaques in clonal hematopoiesis

Clonal hematopoiesis (CH) is an independent risk factor for atherosclerotic cardiovascular disease. Murine models of CH suggest a central role of inflammasomes and IL-1β in accelerated atherosclerosis and plaque destabilization. Here we show using single-cell RNA sequencing in human carotid plaques that inflammasome components are enriched in macrophages, while the receptor for IL-1β is enriched in fibroblasts and smooth muscle cells (SMCs). To address the role of inflammatory crosstalk in features of plaque destabilization, we conducted SMC fate mapping in Ldlr-/- mice modeling Jak2VF or Tet2 CH treated with IL-1β antibodies. Unexpectedly, this treatment minimally affected SMC differentiation, leading instead to a prominent expansion of fibroblast-like cells. Depletion of fibroblasts from mice treated with IL-1β antibody resulted in thinner fibrous caps. Conversely, genetic inactivation of Jak2VF during plaque regression promoted fibroblast accumulation and fibrous cap thickening. Our studies suggest that suppression of inflammasomes promotes plaque stabilization by recruiting fibroblast-like cells to the fibrous cap.

Causes and consequences of clonal hematopoiesis

ABSTRACT

Clonal hematopoiesis (CH) is described as the outsized contribution of expanded clones of hematopoietic stem and progenitor cells (HSPCs) to blood cell production. The prevalence of CH increases dramatically with age. CH can be caused by somatic mutations in individual genes or by gains and/or losses of larger chromosomal segments. CH is a premalignant state; the somatic mutations detected in CH are the initiating mutations for hematologic malignancies, and CH is a strong predictor of the development of blood cancers. Moreover, CH is associated with nonmalignant disorders and increased overall mortality. The somatic mutations that drive clonal expansion of HSPCs can alter the function of terminally differentiated blood cells, including the release of elevated levels of inflammatory cytokines. These cytokines may then contribute to a broad range of inflammatory disorders that increase in prevalence with age. Specific somatic mutations in the peripheral blood in coordination with blood count parameters can powerfully predict the development of hematologic malignancies and overall mortality in CH. In this review, we summarize the current understanding of CH nosology and origins. We provide an overview of available tools for risk stratification and discuss management strategies for patients with CH presenting to hematology clinics.

Molecular and clinical aspects relevant for counseling individuals with clonal hematopoiesis of indeterminate potential

Clonal hematopoiesis of indeterminate potential (CHIP) has fascinated the medical community for some time. Discovered about a decade ago, this phenomenon links age-related alterations in hematopoiesis not only to the later development of hematological malignancies but also to an increased risk of early-onset cardiovascular disease and some other disorders. CHIP is detected in the blood and is characterized by clonally expanded somatic mutations in cancer-associated genes, predisposing to the development of hematologic neoplasms such as MDS and AML. CHIP-associated mutations often involve DNA damage repair genes and are frequently observed following prior cytotoxic cancer therapy. Genetic predisposition seems to be a contributing factor. It came as a surprise that CHIP significantly elevates the risk of myocardial infarction and stroke, and also contributes to heart failure and pulmonary hypertension. Meanwhile, evidence of mutant clonal macrophages in vessel walls and organ parenchyma helps to explain the pathophysiology. Besides aging, there are some risk factors promoting the appearance of CHIP, such as smoking, chronic inflammation, chronic sleep deprivation, and high birth weight. This article describes fundamental aspects of CHIP and explains its association with hematologic malignancies, cardiovascular disorders, and other medical conditions, while also exploring potential progress in the clinical management of affected individuals. While it is important to diagnose conditions that can lead to adverse, but potentially preventable, effects, it is equally important not to stress patients by confronting them with disconcerting findings that cannot be remedied. Individuals with diagnosed or suspected CHIP should receive counseling in a specialized outpatient clinic, where professionals from relevant medical specialties may help them to avoid the development of CHIP-related health problems. Unfortunately, useful treatments and clinical guidelines for managing CHIP are still largely lacking. However, there are some promising approaches regarding the management of cardiovascular disease risk. In the future, strategies aimed at restoration of gene function or inhibition of inflammatory mediators may become an option.

Epigenetic Mechanisms in Hematologic Aging and Premalignant Conditions

Hematopoietic stem cells (HSCs) are essential for maintaining overall health by continuously generating blood cells throughout an individual's lifespan. However, as individuals age, the hematopoietic system undergoes significant functional decline, rendering them more susceptible to age-related diseases. Growing research evidence has highlighted the critical role of epigenetic regulation in this age-associated decline. This review aims to provide an overview of the diverse epigenetic mechanisms involved in the regulation of normal HSCs during the aging process and their implications in aging-related diseases. Understanding the intricate interplay of epigenetic mechanisms that contribute to aging-related changes in the hematopoietic system holds great potential for the development of innovative strategies to delay the aging process. In fact, interventions targeting epigenetic modifications have shown promising outcomes in alleviating aging-related phenotypes and extending lifespan in various animal models. Small molecule-based therapies and reprogramming strategies enabling epigenetic rejuvenation have emerged as effective approaches for ameliorating or even reversing aging-related conditions. By acquiring a deeper understanding of these epigenetic mechanisms, it is anticipated that interventions can be devised to prevent or mitigate the rates of hematologic aging and associated diseases later in life. Ultimately, these advancements have the potential to improve overall health and enhance the quality of life in aging individuals.

Next-generation therapy for lower-risk MDS

Myelodysplastic syndromes (MDS) are malignant myeloid neoplasms characterized by ineffective clonal hematopoiesis leading to peripheral blood cytopenia and a variable risk of transformation to acute myeloid leukemia. In lower-risk (LR) MDS, as defined by prognostic scoring systems recently updated with the addition of a mutation profile, therapeutic options aim to reduce cytopenia, mainly anemia. Although options for reducing the transfusion burden have recently been improved, erythropoiesis-stimulating agents (ESAs), lenalidomide, hypomethylating agents, and, more recently, luspatercept have shown efficacy in rarely more than 50% of patients with a duration of response often far inferior to the patient's life expectancy. Nevertheless, several new therapies are currently under investigation aiming at improving cytopenia in patients with LR-MDS, mostly by targeting different biological pathways. Targeting ligands of the transforming growth factor β pathway has led to the approval of luspatercept in LR-MDS with ring sideroblasts or SF3B1 mutation, potentially replacing first-line ESAs in this population. Here, we also discuss the evolving standard of care for the treatment of LR-MDS and explore some of the most promising next-generation agents under investigation.

JAK2 V617F Mutation and Large Cerebral Artery Disease in Patients with Myeloproliferative Neoplasms

AIM

The aim of the present study was to clarify the association between the Janus kinase 2 (JAK2) V617F mutation and large cerebral artery disease (LCAD) in patients with myeloproliferative neoplasms (MPNs).

METHODS

We retrospectively analysed patients diagnosed with MPNs between June 1992 and June 2022 who underwent brain magnetic resonance imaging. LCAD was defined as extracranial or intracranial large artery stenosis (≥ 50%) or occlusion on magnetic resonance angiography.

RESULTS

A total of 86 patients (47 males; median age, 69 years old) were enrolled in this study. JAK2 V617F mutation was detected in 63 (73.3%) patients and LCAD in 35 (40.7%) patients. Univariate analysis showed that history of ischaemic stroke (LCAD, 62.9% vs. non-LCAD, 11.8%; P＜0.001), JAK2 V617F mutation (91.4% vs. 60.8%, P=0.002), and age ≥ 60 years (85.7% vs. 60.8%, P=0.016) were significantly associated with LCAD. Multiple logistic regression analysis showed that, in addition to ischaemic stroke, age ≥ 60 years and diabetes mellitus, JAK2 V617F mutation (odds ratio 29.2, 95% confidence interval 1.2-709.8, P=0.038) was independently associated with LCAD. LCAD was frequently observed in the intracranial carotid (14/35, 40.0%) and middle cerebral (13/35, 37.1%) arteries.

CONCLUSIONS

This study revealed a significant association between the JAK2 V617F mutation and LCAD in patients with MPNs. This suggests that the JAK2 V617F mutation may promote cerebrovascular atherosclerosis and could be very important in determining therapeutic strategies for patients with not only JAK2 V617F-mutated MPNs but also LCAD-related stroke.

Bridging the Gap: Investigating the Link between Inflammasomes and Postoperative Cognitive Dysfunction

Postoperative cognitive dysfunction (POCD) is a cluster of cognitive problems that may arise after surgery. POCD symptoms include memory loss, focus inattention, and communication difficulties. Inflammasomes, intracellular multiprotein complexes that control inflammation, may have a significant role in the development of POCD. It has been postulated that the NLRP3 inflammasome promotes cognitive impairment by triggering the inflammatory response in the brain. Nevertheless, there are many gaps in the current literature to understand the underlying pathophysiological mechanisms and develop future therapy. This review article underlines the limits of our current knowledge about the NLRP3 (NOD-, LRR- and pyrin domain-containing protein 3) inflammasome and POCD. We first discuss inflammasomes and their types, structures, and functions, then summarize recent evidence of the NLRP3 inflammasome's involvement in POCD. Next, we propose a hypothesis that suggests the involvement of inflammasomes in multiple organs, including local surgical sites, blood circulation, and other peripheral organs, leading to systemic inflammation and subsequent neuronal dysfunction in the brain, resulting in POCD. Research directions are then discussed, including analyses of inflammasomes in more clinical POCD animal models and clinical trials, studies of inflammasome types that are involved in POCD, and investigations into whether inflammasomes occur at the surgical site, in circulating blood, and in peripheral organs. Finally, we discuss the potential benefits of using new technologies and approaches to study inflammasomes in POCD. A thorough investigation of inflammasomes in POCD might substantially affect clinical practice.

Gasdermin D-Mediated Pyroptosis in Diabetic Cardiomyopathy: Molecular Mechanisms and Pharmacological Implications

Diabetic cardiomyopathy (DCM) is a pathophysiological condition triggered by diabetes mellitus (DM), which can lead to heart failure (HF). One of the most important cellular processes associated with DCM is the death of cardiomyocytes. Gasdermin D (GSDMD) plays a key role in mediating pyroptosis, a type of programmed cell death closely associated with inflammasome activation. Recent studies have revealed that pyroptosis is induced during hyperglycemia, which is crucial to the development of DCM. Although the effects of pyroptosis on DCM have been discussed, the relationship between DCM and GSDMD is not fully clarified. Recent studies gave us the impetus for clarifying the meaning of GSDMD in DCM. The purpose of this review is to summarize new and emerging insights, mainly discussing the structures of GSDMD and the mechanism of pore formation, activation pathways, molecular mechanisms of GSDMD-mediated pyroptosis, and the therapeutic potential of GSDMD in DCM. The implications of this review will pave the way for a new therapeutic target in DCM.