IRF3 and type I interferons fuel a fatal response to myocardial infarction

Functional diversity of cardiac macrophages in health and disease

Macrophages make up a substantial portion of the stromal compartment of the heart in health and disease. In the past decade, the origins of these cardiac macrophages have been established as two broad populations derived from either embryonic or definitive haematopoiesis and that can be distinguished by the expression of CC-motif chemokine receptor 2 (CCR2). These cardiac macrophage populations are transcriptionally distinct and have differing cell surface markers and divergent roles in cardiac homeostasis and disease. Embryonic-derived CCR2- macrophages are a tissue-resident population that participates in tissue development, repair and maintenance, whereas CCR2+ macrophages are derived from definitive haematopoiesis and contribute to inflammation and tissue damage. Studies from the past 5 years have leveraged single-cell RNA sequencing technologies to expand our understanding of cardiac macrophage diversity, particularly of the monocyte-derived macrophage populations that reside in the injured and diseased heart. Emerging technologies in spatial transcriptomics have enabled the identification of distinct disease-associated cellular neighbourhoods consisting of macrophages, other immune cells and fibroblasts, highlighting the involvement of macrophages in cell-cell communication. Together, these discoveries lend new insights into the role of specific macrophage populations in the pathogenesis of cardiac disease, which can pave the way for the identification of new therapeutic targets and the development of diagnostic tools. In this Review, we discuss the developmental origin of cardiac macrophages and describe newly identified cell states and associated cellular neighbourhoods in the steady state and injury settings. We also discuss various contributions and effector functions of cardiac macrophages in homeostasis and disease.

Tanshinone IIA alleviates myocarditis in Trex1-D18N lupus-like mice by inhibiting the interaction between STING and SEC24C

The cyclic GMP-AMP synthase-stimulator of interferon genes (cGAS-STING) signaling pathway serves as a crucial component of the innate immune defense, playing a vital role in combating pathogen invasion. However, its dysregulation or abnormal activation can trigger the development of autoimmune diseases. This study demonstrated that Tanshinone IIA, a major lipid-soluble component of Salvia miltiorrhiza Bunge, can effectively inhibit the activation of the cGAS-STING signaling pathway. Mechanistically, Tanshinone IIA inhibits the transport of STING from the ER to the Golgi apparatus by weakening the interaction between STING and SEC24C, thereby preventing the activation of the cGAS-STING signaling pathway. Furthermore, Tanshinone IIA significantly ameliorated myocardial inflammation in WT and Trex1D18N/D18N mice. Our research indicates that Tanshinone IIA shows potential therapeutic value in alleviating autoimmune diseases by effectively inhibiting the abnormal activation of the cGAS-STING pathway.

Heterozygous interferon signaling deficient mice as animal models for Chikungunya virus infection in the heart

Although chikungunya virus (CHIKV)-caused cardiovascular diseases are frequently reported in clinics, the underlying mechanisms are poorly understood, which is primarily due to a lack of animal models. In this study, we report that CHIKV infection in homozygous interferon α/β receptor-deficient (ifnar1-/-) and interferon α/β/γ receptor-deficient (ifnag-/-) mice resulted in high viral loads in the hearts as early as day (D) 1 post-infection (p.i.) but with 100% mortality within three days p.i. In contrast, the heterozygous ifnar1+/-and ifnag+/- mice survived CHIKV infection and bore higher viral burdens in the heart tissues than the wild-type (WT) controls. Immunohistochemistry and flow cytometry revealed that more leukocytes, particularly neutrophils, infiltrated the heart of ifnag+/- and ifnar1+/- mice than WT mice. In addition, the Hematoxylin and Eosin staining analysis showed that CHIKV infection caused vasculitis in the left ventricles on D5 p.i. in both heterozygous groups and the vacuole formation and pyknosis in ifnar1+/- mice. Moreover, CHIKV infection may also lead to cardiac fibrosis, as indicated by the upregulation of the expression of the Connective Tissue Growth Factor gene in the hearts of ifnar1+/- mice. In summary, our data suggest that the heterozygous ifnar1+/- and ifnag+/- mice are invaluable for studying pathogenesis and testing therapeutic interventions for CHIKV-caused cardiac diseases.

cGAS-STING Pathway's Impact on Intestinal Barrier

Intestinal inflammation and increased permeability have been linked to metabolic dysregulation in patients with compromised intestinal barrier function. Among the pathways, garnering attention is the cyclic GMP-AMP synthase-stimulator of interferon genes (cGAS-STING) pathway. Upon binding to double-stranded DNA (dsDNA), cGAS catalyzes the conversion of ATP and GTP into cyclic GMP-AMP (cGAMP). Subsequently, cGAMP binds to STING, triggering the activation of tank-binding kinase 1 (TBK1), which activates interferon regulatory factor 3 (IRF3), thus inducing the production of type I interferon. Activated TBK1 can also induce the activation of nuclear factor κB (NF-κB), thus mediating the production of proinflammatory cytokines. The effects of this process vary among innate and adaptive immune cells, as well as intestinal epithelial cells (IECs). This review aims to elucidate the impact and role of the cGAS-STING pathway on intestinal barrier function.

The cGAS-STING pathway promotes acute ischemia-induced neutropoiesis and neutrophil priming in the bone marrow

Our previous work demonstrated that the DNA-sensing receptor cyclic GMP-AMP synthase (cGAS) negatively affects post-infarct repair by promoting pro-inflammatory macrophages. However, whether cGAS and its downstream partner STING (Stimulator of Interferon Genes) regulate neutrophil production and function in the context of acute myocardial ischemia remains unclear. This study investigated the role of the cGAS-STING pathway in neutropoiesis (neutrophil production and differentiation) and examined whether ischemia primes neutrophils in the bone marrow via this pathway, enhancing their functionality and contributing to cardiac inflammatory injury. Using myocardial infarction (MI) models in wild-type (WT), Cgas-/-, and Sting-/- mice, we analyzed neutrophils from the bone marrow, peripheral blood, and infarcted tissue. Additionally, we generated neutrophil-specific conditional knockouts of Cgas and performed adoptive transfer experiments with Cgas-deficient neutrophils. RNA sequencing revealed that ischemia increased neutrophil production in the bone marrow and activated pathways involved in cytokine signaling, phagocytosis, chemotaxis, and degranulation. Inhibiting the cGAS-STING pathway reduced neutrophil production by decreasing lineage committed neutrophil precursors including early neutrophil precursors (eNP) and preNeu and downregulated ischemia-induced pathways. Neutrophil conditional Cgas deletion or adoptive transfer of Cgas-deficient neutrophils improved survival but did not significantly impact ischemia-induced remodeling. In conclusion, we demonstrate for the first time that ischemia enhanced neutrophil functionality before recruitment to infarcted tissue, and the cGAS-STING pathway played an important role in neutrophil production and priming. Furthermore, our findings demonstrate a neutrophil-specific role of cGAS in promoting cardiac rupture and mortality in MI. This study provides a more comprehensive understanding of the cGAS-STING pathway in acute ischemia and may support the translation of cGAS-STING modulators, an emerging therapeutic field.

Immune-mediated cardiac development and regeneration

The complex interplay between the immune and cardiovascular systems during development, homeostasis and regeneration represents a rapidly evolving field in cardiac biology. Single cell technologies, spatial mapping and computational analysis have revolutionised our understanding of the diversity and functional specialisation of immune cells within the heart. From the earliest stages of cardiogenesis, where primitive macrophages guide heart tube formation, to the complex choreography of inflammation and its resolution during regeneration, immune cells emerge as central orchestrators of cardiac fate. Translating these fundamental insights into clinical applications represents a major challenge and opportunity for the field. In this Review, we decode the immunological blueprint of heart development and regeneration to transform cardiovascular disease treatment and unlock the regenerative capacity of the human heart.

Macrophage-Derived Type 1 IFN, Renal Tubular Epithelial Cell Polyploidization, and AKI-to-CKD Transition

Key Points

Macrophage-derived IFN-β contributes to tubular epithelial cell polyploidization after AKI. IFN-β induced tubular epithelial cell polyploidization by regulating inorganic pyrophosphatase-mediated yes-associated protein (YAP) dephosphorylation. Delayed blockade of the IFN-β response attenuated persistent polyploidization and kidney fibrosis.

Background

AKI is recognized as a common risk factor of CKD. Renal tubular epithelial cell polyploidization after AKI is closely associated with maladaptive repair, while the regulatory and molecular mechanisms remain poorly understood. In this study, we set out to investigate the mechanism of tubular epithelial cell polyploidization and their role in AKI-to-CKD transition.

Methods

The change characters of polyploid tubular epithelial cells and macrophages after AKI were detected by flow cytometry and immunofluorescence. The underlying mechanism was explored by RNA-sequencing analysis, immunofluorescence, and Western blot. The role of tubular epithelial cell polyploidization in AKI-to-CKD transition was evaluated by transgenic mice and drug interventions.

Results

We discovered that tubular epithelial cells underwent polyploidization after AKI, and polyploid tubular epithelial cells exhibited greater fibrotic phenotypes than nonpolyploid cells. Furthermore, we revealed an upregulated IFN-β response feature within tubular epithelial cells after AKI and identified that macrophage-derived IFN-β bound to IFN-I receptor 1 of tubular epithelial cells and induced their polyploidization. Mechanistically, IFN-β , secreted by macrophages through activation of the cyclic guanosine monophosphate-AMP synthase-stimulator of IFN genes pathway, acted on tubular epithelial cells and facilitated inorganic pyrophosphatase binding to yes-associated protein (YAP), which mediated YAP dephosphorylation and subsequent nuclear translocation, culminating in p21 expression and polyploidization. Importantly, delayed blockade of the IFN-β response and pharmacological inhibition of stimulator of IFN genes or YAP activation on day 4 after AKI significantly attenuated persistent tubular epithelial cell polyploidization and AKI-induced kidney fibrosis.

Conclusions

Macrophage-derived IFN-β contributed to tubular epithelial cell polyploidization by regulating inorganic pyrophosphatase/YAP signaling pathway–mediated p21 expression and further promoted AKI-to-CKD transition.

Suppression of the Prostaglandin I2-Type 1 Interferon Axis Induces Extramedullary Hematopoiesis to Promote Cardiac Repair After Myocardial Infarction

BACKGROUND

Immune cells are closely associated with all processes of cardiac repair after myocardial infarction (MI), including the initiation, development, and resolution of inflammation. Spleen extramedullary hematopoiesis (EMH) serves as a crucial source of emergency mature blood cells that are generated through the self-renewal and differentiation of hematopoietic stem/progenitor cells (HSPCs). However, how EMH responds to MI and the role of EMH in cardiac repair after MI remains unclear.

METHODS

To assess the role of spleen EMH in MI, a Tcf21CreER Scfflox/flox MI mouse model with inhibited EMH was constructed. GFP+ (green fluorescent protein) hematopoietic stem cells were sorted from eGFP (enhanced green fluorescent protein) mouse spleen by flow cytometry and injected into Tcf21CreER Scfflox/flox mice to test the sources of local inflammatory cells during MI. Using highly specific liquid chromatography-tandem mass spectrometry and single-cell RNA sequencing, we analyzed the lipidomic profile of arachidonic acid metabolites and the transcriptomes of HSPCs in the spleen after MI.

RESULTS

We found that MI enhanced EMH, as reflected by the increase in spleen weight and volume and the number of HSPCs in the spleen. The lack of EMH in Scf-deficient mice exacerbated tissue injury after MI. Analysis of the transcriptome of spleen HSPCs after MI revealed that the type 1 interferon pathway was substantially inhibited in hematopoietic stem cell/multipotent progenitor subclusters, and the absence of type 1 interferon signaling enhanced the MI-induced spleen EMH. Lipidomics analysis revealed that prostaglandin I2 (PGI2) was markedly reduced in the spleen. PGI2 suppressed MI-induced EMH through a PGI2 receptor (IP)-cyclic adenosine monophosphate-453p-SP1 cascade in spleen HSPCs. Hematopoietic cell-specific IP-deficient mice exhibited enhanced EMH and improved cardiac recovery after MI.

CONCLUSIONS

Together, our findings revealed that a PGI2-IFN axis was involved in spleen EMH after MI, providing new mechanistic insights into spleen EMH after MI and offering a new therapeutic target for treating ischemic cardiac injury.

Direct cell interactions potentially regulate transcriptional programmes that control the responses of high grade serous ovarian cancer patients to therapy

The tumour microenvironment is composed of a complex cellular network involving cancer, stromal and immune cells in dynamic interactions. A large proportion of this network relies on direct physical interactions between cells, which may impact patient responses to clinical therapy. Doublets in scRNA-seq are usually excluded from analysis. However, they may represent directly interacting cells. To decipher the physical interaction landscape in relation to clinical prognosis, we inferred a physical cell-cell interaction (PCI) network from 'biological' doublets in a scRNA-seq dataset of approximately 18,000 cells, obtained from 7 treatment-naive ovarian cancer patients. Focusing on cancer-stromal PCIs, we uncovered molecular interaction networks and transcriptional landscapes that stratified patients in respect to their clinical responses to standard therapy. Good responders featured PCIs involving immune cells interacting with other cell types including cancer cells. Poor responders lacked immune cell interactions, but showed a high enrichment of cancer-stromal PCIs. To explore the molecular differences between cancer-stromal PCIs between responders and non-responders, we identified correlating gene signatures. We constructed ligand-receptor interaction networks and identified associated downstream pathways. The reconstruction of gene regulatory networks and trajectory analysis revealed distinct transcription factor (TF) clusters and gene modules that separated doublet cells by clinical outcomes. Our results indicate (i) that transcriptional changes resulting from PCIs predict the response of ovarian cancer patients to standard therapy, (ii) that immune reactivity of the host against the tumour enhances the efficacy of therapy, and (iii) that cancer-stromal cell interaction can have a dual effect either supporting or inhibiting therapy responses.

STING aggravates ferroptosis-dependent myocardial ischemia-reperfusion injury by targeting GPX4 for autophagic degradation

Despite advancements in interventional coronary reperfusion technologies following myocardial infarction, a notable portion of patients continue to experience elevated mortality rates as a result of myocardial ischemia-reperfusion (MI/R) injury. An in-depth understanding of the mechanisms underlying MI/R injury is crucial for devising strategies to minimize myocardial damage and enhance patient survival. Here, it is discovered that during MI/R, double-stranded DNA (dsDNA)-cyclic GMP-AMP synthase (cGAS)-stimulator of interferon genes (STING) signal accumulates, accompanied by high rates of myocardial ferroptosis. The specific deletion of cgas or Sting in cardiomyocytes, resulting in the inhibition of oxidative stress, has been shown to mitigate ferroptosis and I/R injury. Conversely, activation of STING exacerbates ferroptosis and I/R injury. Mechanistically, STING directly targets glutathione peroxidase 4 (GPX4) to facilitate its degradation through autophagy, by promoting the fusion of autophagosomes and lysosomes. This STING-GPX4 axis contributes to cardiomyocyte ferroptosis and forms a positive feedback circuit. Blocking the STING-GPX4 interaction through mutations in T267 of STING or N146 of GPX4 stabilizes GPX4. Therapeutically, AAV-mediated GPX4 administration alleviates ferroptosis induced by STING, resulting in enhanced cardiac functional recovery from MI/R injury. Additionally, the inhibition of STING by H-151 stabilizes GPX4 to reverse GPX4-induced ferroptosis and alleviate MI/R injury. Collectively, a novel autophagy-dependent ferroptosis mechanism is identified in this study. Specifically, STING autophagy induced by anoxia or ischemia-reperfusion leads to GPX4 degradation, thereby presenting a promising therapeutic target for heart diseases associated with I/R.

Advances in Therapeutic Targets and Traditional Chinese Medicine for Cardiomyopathy

Cardiomyopathy is a kind of heart disease caused by multiple factors of myocardial structure and function disorders. In this paper, we summarized and found the targets and mechanisms with therapeutic potential by querying the relevant literature on cardiomyopathy in the past 10 years from databases. Numerous pieces of literature have proven the significant efficacy of traditional Chinese medicine (TCM) in the treatment of cardiomyopathy. Through effective screening methods, we quickly identified a variety of commonly used Chinese herbs such as Astragalus, Danggui, Danshen, Pueraria Root, and ginseng, and further analyzed the active ingredients that play key roles in the treatment of cardiomyopathy. Specifically, our study revealed significant interaction activity at the molecular level of active ingredients such as calycosin, formononetin, and beta-sitosterol, which were strongly validated by sophisticated molecular docking experiments. These active ingredients can be precisely combined with 14 core targets (such as AKT1, TP53, IL6, and other key proteins), which not only reveals their potential therapeutic mechanisms but also provides direct and solid scientific support for the application of TCM in the treatment of cardiomyopathy. It is helpful to develop new TCM preparations further and provide more treatment options for patients with cardiomyopathy.

Mitochondrial dysfunction in AMI: mechanisms and therapeutic perspectives

Acute myocardial infarction (AMI) and the myocardial ischemia-reperfusion injury (MI/RI) that typically ensues represent a significant global health burden, accounting for a considerable number of deaths and disabilities. In the context of AMI, percutaneous coronary intervention (PCI) is the preferred treatment option for reducing acute ischemic damage to the heart. Despite the modernity of PCI therapy, pathological damage to cardiomyocytes due to MI/RI remains an important target for intervention that affects the long-term prognosis of patients. In recent years, mitochondrial dysfunction during AMI has been increasingly recognized as a critical factor in cardiomyocyte death. Damaged mitochondria play an active role in the formation of an inflammatory environment by triggering key signaling pathways, including those mediated by cyclic GMP-AMP synthase, NOD-like receptors and Toll-like receptors. This review emphasizes the dual role of mitochondria as both contributors to and regulators of inflammation. The aim is to explore the complex mechanisms of mitochondrial dysfunction in AMI and its profound impact on immune dysregulation. Specific interventions including mitochondrial-targeted antioxidants, membrane-stabilizing peptides, and mitochondrial transplantation therapies have demonstrated efficacy in preclinical AMI models.

The Application of scRNA-Seq in Heart Development and Regeneration

Single-cell RNA sequencing (scRNA-seq) is a rapidly developing and useful technique for elucidating biological mechanisms and characterizing individual cells. Tens of millions of patients worldwide suffer from heart injuries and other types of heart disease. Neonatal mammalian hearts and certain adult vertebrate species, such as zebrafish, can fully regenerate after myocardial injury. However, the adult mammalian heart is unable to regenerate the damaged myocardium. scRNA-seq provides many new insights into pathological and normal hearts and facilitates our understanding of cellular responses to cardiac injury and repair at different stages, which may provide critical clues for effective therapies for adult heart regeneration. In this review, we summarize the application of scRNA-seq in heart development and regeneration and describe how important molecular mechanisms can be harnessed to promote heart regeneration.

Amelioration of Isoproterenol-Induced Myocardial Infarction by the Phytochemical Koenigicine via Modulation of NF-κB/HO-1/NQO-1 Pathways: An In Vivo Analysis

Phytochemicals exhibit diverse cardioprotective properties that contribute to the prevention and management of myocardial infarction (MI). In our study, we examined the potency of the phytochemical Koenigicine, which belongs to the carbazole alkaloid, in alleviating MI in an animal model. The animals were supplemented with Koenigicine before MI induction using isoproterenol, with supplementation continuing during the MI induction period. The impact of Koenigicine on mitigating the onset of MI was evaluated by quantifying lipid levels and arterial blood pressure. Its ameliorative potential against isoproterenol-induced cardiac damage was assessed by measuring antioxidant levels and critical biomarkers of MI in the experimental animals. Protein, C-reactive protein (CRP), and uric acid levels were assessed to determine the effect of Koenigicine on immune function and inflammation. Additionally, the impact of Koenigicine on cardiac muscle function and its role in healing ischemic-induced cardiac tissues were examined in MI-induced rats. The effect of Koenigicine treatment on post-ischemic injury was analyzed by quantifying NF-κB, HO-1, and NQO-1 levels, and the findings were confirmed through cardiac histopathological analysis. Koenigicine administration effectively mitigated MI induction by regulating lipid levels and arterial blood pressure. It enhanced the antioxidant defense system, attenuated inflammatory signaling, and thereby prevented MI-induced cardiac tissue damage. The results of MI biomarker analysis confirmed the ameliorative potential of Koenigicine against isoproterenol-induced cardiac inflammation. Furthermore, it demonstrated a positive effect on cardiac function and facilitated the healing process following MI induction. Overall, our findings suggest that Koenigicine provides preventive, suppressive, and ameliorative effects at all stages of MI, addressing gaps in the efficacy of currently available treatments.

Dual-tDCS Ameliorates Cerebral Injury and Promotes Motor Function Recovery via cGAS-STING Signaling Pathway in a Rat Model of Ischemic Stroke

Ischemic stroke is one of the leading causes of death and disability. Dual transcranial direct current stimulation (dual-tDCS) is a promising intervention to treat ischemic stroke, but its efficacy and underlying mechanism remain to be verified. Cyclic GMP-AMP synthase (cGAS)-stimulator of interferon genes (STING) pathway has recently emerged as a key mediator in cerebral injury. However, little is known about the effect of cGAS-STING on neuronal damage in ischemic stroke, and it remains to be studied whether the cGAS-STING pathway is involved in tDCS intervention for ischemic stroke. Therefore, we aimed to investigate whether dual-tDCS can alleviate ischemic brain injury in a rat model of ischemic stroke and if so, whether via cGAS-STING pathway. Middle cerebral artery occlusion (MCAO) was employed to induce a rat model of ischemic stroke. Male SD rats weighing 250-280 g were randomly assigned to the Sham, MCAO, Dual-tDCS, Dual-tDCS + RU.521, and Dual-tDCS + 2'3'-cGAMP groups, with 10 rats in each group completing the experiment. Behavioral, morphological, MRI, and molecular biological methods were performed. We found that the cGAS-STING pathway was activated and expressed in neurons after MCAO. Dual-tDCS improved motor function and infarct volume, inhibited neuronal apoptosis, promoted the expression of neurotrophins (BDNF and NGF), CD31, and VEGF, and suppressed inflammation reaction after MCAO via the cGAS-STING pathway. Taken together, dual-tDCS may improve MCAO-induced brain injury and promote the recovery of motor function, resulting from the inhibition of neuronal apoptosis and inflammation reaction, as well as promotion of the expression of nerve plasticity- and angiogenesis-related proteins, via cGAS-STING pathway.

Redefining Macrophage Heterogeneity in Atherosclerosis: A Focus on Possible Therapeutic Implications

Atherosclerosis is a lipid disorder where modified lipids (especially oxidized LDL) induce macrophage foam cell formation in the aorta. Its pathogenesis involves a continuum of persistent inflammation accompanied by dysregulated anti-inflammatory responses. Changes in the immune cell status due to differences in the lesional microenvironment are crucial in terms of plaque development, its progression, and plaque rupture. Ly6Chi monocytes generated through both medullary and extramedullary cascades act as one of the major sources of plaque macrophages and thereby foam cells. Both monocytes and monocyte-derived macrophages also participate in pathological events in atherosclerosis-associated multiple organ systems through inter-organ communications. For years, macrophage phenotypes M1 and M2 have been shown to perpetuate inflammatory and resolution responses; nevertheless, such a dualistic classification is too simplistic and contains severe drawbacks. As the lesion microenvironment is enriched with multiple mediators that possess the ability to activate macrophages to diverse phenotypes, it is obvious that such cells should demonstrate substantial heterogeneity. Considerable research in this regard has indicated the presence of additional macrophage phenotypes that are exclusive to atherosclerotic plaques, namely Mox, M4, Mhem, and M(Hb) type. Furthermore, although the concept of macrophage clusters has come to the fore in recent years with the evolution of high-dimensional techniques, classifications based on such 'OMICS' approaches require extensive functional validation as well as metabolic phenotyping. Bearing this in mind, the current review provides an overview of the status of different macrophage populations and their role during atherosclerosis and also outlines possible therapeutic implications.

The CGAS-STING1 Pathway as a Mediator of Innate Immune Response in Cardiovascular Disease

The innate immune response, a rapid and cell-autonomous response of the cell to the pathogens, recognizes the external as well as the internal pathogens, such as self-DNA, released from the damaged cells. The response activates a set of molecules that induce the expression of proinflammatory cytokines and chemokines and leads to inflammation, fibrosis, and cell death. The innate immune response comprised of DNA-sensing protein cyclic guanosine monophosphate-adenosine monophosphate synthase (CGAS) and its downstream molecules, the stimulator of interferon genes 1 (STING1), TANK-binding kinase 1 (TBK1), interferon regulatory factor 3 (IRF3), and nuclear factor kappa B (NFκB), are activated in several cardiovascular diseases, including hereditary cardiomyopathies, myocardial infarction, hypertension, atherosclerosis, and aortic aneurysm. The genetic deletion of key molecules in this pathway, such as CGAS, STING1, and interferon regulatory factor 3, affords salubrious effects, including improving survival and cardiac dysfunction, rendering the CGAS-STING1 pathway an attractive therapeutic target in cardiovascular disease.

Esketamine alleviated cardiomyocyte ferroptosis induced by oxygen-glucose deprivation/reoxygenation (OGD/R) via cyclic GMP-AMP synthase interactor

Background

The use of tourniquets (TQ) during the total knee arthroplasty (TKA) induced ischemia-reperfusion (I/R) injury in the limb, resulting in the release of inflammatory cytokines and reactive oxygen species (ROS), therefore leading to myocardial damage. This study aimed to investigate the effects and molecular mechanism of Esketamine on myocardial injury (MI) caused by TQ-induced I/R injury.

Methods

A randomized numerical table method was used to divide 23 patients into the C group (11 cases, ACB + conventional anesthesia) and M group (12 cases, ACB + conventional anesthesia + 0.5 mg/kg Esketamine). The levels of lactate dehydrogenase (LDH), Malondialdehyde (MDA), Fe2+, Glutathione Peroxidase (GSH-Px), glutathione (GSH), IL-6, TNF-α, Creatine Kinase (CK) and CreatineKinase-MB (CKMB) were determined by reagent kits. The expression of CGAMP interaction factor (STING), Glutathione Peroxidase 4 (GPX4), and Ferritin Heavy Chain 1 (FTH1) was examined by Western blot. The ROS level was tested by flow cytometry. The expression of STING was validated by immunofluorescence.

Results

Compared with the C group, the levels of GSH-Px and GSH were increased while the levels of IL-6, TNF-α, MDA, Fe2+, CK, CKMB, and LDH were decreased in the M group. Furthermore, esketamine relieved the OGD/R-induced increase of MDA, Fe2+, and ROS and the decrease of GSH-Px, GSH, GPX4, and FTH1, which were reversed by STING overexpression.

Conclusion

Esketamine alleviated cardiomyocyte ferroptosis via STING, which might be the molecular mechanism of Esketamine to ameliorate the MI caused by TQ-induced I/R injury.

Supplementary Information

The online version contains supplementary material available at 10.1007/s10616-025-00723-9.

Causes and consequences of DNA double-stranded breaks in cardiovascular disease

The genome, whose stability is essential for survival, is incessantly exposed to internal and external stressors, which introduce an estimated 104 to 105 lesions, such as oxidation, in the nuclear genome of each mammalian cell each day. A delicate homeostatic balance between the generation and repair of DNA lesions maintains genomic stability. To initiate transcription, DNA strands unwind to form a transcription bubble and provide a template for the RNA polymerase II (RNAPII) complex to synthesize nascent RNA. The process generates DNA supercoils and introduces torsional stress. To enable RNAPII processing, the supercoils are released by topoisomerases by introducing strand breaks, including double-stranded breaks (DSBs). Thus, DSBs are intrinsic genomic features of gene expression. The breaks are quickly repaired upon processing of the transcription. DNA lesions and damaged proteins involved in transcription could impede the integrity and efficiency of RNAPII processing. The impediment, which is referred to as transcription stress, not only could lead to the generation of aberrant RNA species but also the accumulation of DSBs. The latter is particularly the case when topoisomerase processing and/or the repair mechanisms are compromised. The DSBs activate the DNA damage response (DDR) pathways to repair the damaged DNA and/or impose cell cycle arrest and cell death. In addition, the release of DSBs into the cytosol activates the cytosolic DNA-sensing proteins (CDSPs), which along with the nuclear DDR pathways induce the expression of senescence-associated secretory phenotype (SASP), cell cycle arrest, senescence, cell death, inflammation, and aging. The primary stimulus in hereditary cardiomyopathies is a mutation(s) in genes encoding the protein constituents of cardiac myocytes; however, the phenotype is the consequence of intertwined complex interactions among numerous stressors and the causal mutation(s). Increased internal DNA stressors, such as oxidation, alkylation, and cross-linking, are expected to be common in pathological conditions, including in hereditary cardiomyopathies. In addition, dysregulation of gene expression also imposes transcriptional stress and collectively with other stressors provokes the generation of DSBs. In addition, the depletion of nicotinamide adenine dinucleotide (NAD), which occurs in pathological conditions, impairs the repair mechanism and further facilitates the accumulation of DSBs. Because DSBs activate the DDR pathways, they are expected to contribute to the pathogenesis of cardiomyopathies. Thus, interventions to reduce the generation of DSBs, enhance their repair, and block the deleterious DDR pathways would be expected to impart salubrious effects not only in pathological states, as in hereditary cardiomyopathies but also aging.

The neuroimmune nexus: unraveling the role of the mtDNA-cGAS-STING signal pathway in Alzheimer's disease

The relationship between Alzheimer's disease (AD) and neuroimmunity has gradually begun to be unveiled. Emerging evidence indicates that cyclic GMP-AMP synthase (cGAS) acts as a cytosolic DNA sensor, recognizing cytosolic damage-associated molecular patterns (DAMPs), and inducing the innate immune response by activating stimulator of interferon genes (STING). Dysregulation of this pathway culminates in AD-related neuroinflammation and neurodegeneration. A substantial body of evidence indicates that mitochondria are involved in the critical pathogenic mechanisms of AD, whose damage leads to the release of mitochondrial DNA (mtDNA) into the extramitochondrial space. This leaked mtDNA serves as a DAMP, activating various pattern recognition receptors and immune defense networks in the brain, including the cGAS-STING pathway, ultimately leading to an imbalance in immune homeostasis. Therefore, modulation of the mtDNA-cGAS-STING pathway to restore neuroimmune homeostasis may offer promising prospects for improving AD treatment outcomes. In this review, we focus on the mechanisms of mtDNA release during stress and the activation of the cGAS-STING pathway. Additionally, we delve into the research progress on this pathway in AD, and further discuss the primary directions and potential hurdles in developing targeted therapeutic drugs, to gain a deeper understanding of the pathogenesis of AD and provide new approaches for its therapy.

Immune checkpoint inhibitors mediate myocarditis by promoting macrophage polarization via cGAS/STING pathway

BACKGROUND

Immune checkpoint inhibitors has opened up new avenues for cancer treatment, but serious cardiac injury has emerged in their use. A large number of data have shown that abnormal activation of cytosolic DNA-sensing cyclic GMP-AMP synthase-interferon gene activator pathway is closely related to cardiovascular inflammation and autoimmune diseases. However, the pathophysiological function of the cGAS-STING cascade in myocarditis induced by Immune checkpoint inhibitors is unclear.

METHODS

In order to establish a Immune checkpoint inhibitors-associated myocarditis model, BALB/c mice were injected with mouse cardiac troponin I peptide and anti-mouse programmed death 1 antibody. Echocardiography and HE staining were then performed to assess cardiac function and inflammation. Macrophages and damaged DNA in mouse heart tissue were detected by immunofluorescence. The mitochondrial damage of macrophages was observed by electron microscope. In vitro experiments, RAW264.7 was used to detect macrophage polarization after anti-PD-1 antibody induction and STING inhibition by qPCR and flow cytometry. Mitochondrial damage was detected by immunofluorescence, and activation of the cGAS-STING signaling pathway was evaluated by protein imprinting analysis.

RESULTS

In the Immune checkpoint inhibitors-associated myocarditis model, DNA damage was found to activate the cGAS-STING pathway and macrophages were polarized to M1 type. In vitro experiments, anti-PD-1 antibody activate the cGAS-STING pathway through the release of damaged DNA from macrophage mitochondrial damage, causing macrophage polarization into a pro-inflammatory phenotype leading to autoimmune myocarditis.

CONCLUSION

Our results suggested that the cGAS-STING pathway played a key role in myocarditis caused by immune checkpoint inhibitors. It provided a new possibility for Immune checkpoint inhibitors to be widely used in clinic.

Modelling myocardial ischemia/reperfusion injury with inflammatory response in human ventricular cardiac organoids

Current therapeutic drug exploring targeting at myocardial ischemia/reperfusion (I/R) injury is limited due to the lack of humanized cardiac models that resemble myocardial damage and inflammatory response. Herein, we develop ventricular cardiac organoids from human induced pluripotent stem cells (hiPSCs) and simulate I/R injury by hypoxia/reoxygenation (H/R), which results in increased cardiomyocytes apoptosis, elevated oxidative stress, disrupted morphological structure and decreased beat amplitude. RNA-seq reveals a potential role of type I interferon (IFN-I) in this I/R injury model. We then introduce THP-1 cells and reveal inflammatory responses between monocytes/macrophages and H/R-induced ventricular cardiac organoids. Furthermore, we demonstrate Anifrolumab, an FDA approved antagonist of IFN-I receptor, effectively decreases IFN-I secretion and related gene expression, attenuates H/R-induced inflammation and oxidative stress in the co-culture system. This study advances the modelling of myocardial I/R injury with inflammatory response in human cardiac organoids, which provides a reliable platform for preclinical study and drug screening.

Mitochondrial Amount Determines Doxorubicin-Induced Cardiotoxicity in Cardiomyocytes

Doxorubicin, an anthracycline commonly used for treating cancer patients, is known for its cardiotoxic side-effects. Although dose-dependent, but susceptibility remains variable among patients, and childhood-exposure-adult-onset remains challenging. Besides topoisomerase toxicity, Doxorubicin is also toxic to the mitochondria yet the underlying late onset mechanism remains elusive. Here, it is observed that the mitochondrial copy number in PBMCs of patients treated with anthracycline chemotherapy is negatively correlated with the change in plasma BNP levels after treatment. Isogenic hiPSC-CMs are generated with high, norm, and low mitochondrial copy numbers using mitochondrial transplantation and the YFP-Parkin system. Remarkably, lower mitochondria copy number translates to lower IC50, suggesting increased susceptibility. Mitochondria supplementation by intramyocardial injection prevents doxorubicin induced heart failure. Mechanistically, doxorubicin treatment leads to mPTP opening and mitochondrial DNA (mtDNA) leakage. This mtDNA leakage event activates the cGAS-STING pathway and drives inflammation and myocardial senescence. Cardiomyocyte-specific knockout of Sting (Myh6-Cre/Stingflox/flox; StingCKO) and over expression of mitochondrial tagged DNase1 in mice partially rescue doxorubicin-induced cardiac dysfunction. In conclusion, the work establishes a negative correlation between cardiomyocyte mitochondrial copy number and doxorubicin toxicity. Molecularly, it is demonstrated that mtDNA leakage activates cGAS-STING pathway and accelerates myocardial dysfunction. These insights offer new co-administration strategies for cancer patients.

Direct inhibition of macrophage sting signaling by curcumol protects against myocardial infarction via attenuating the inflammatory response

BACKGROUND

Macrophages play a crucial role in the pathological process after myocardial infarction (MI). However, pharmacological therapy targeting this pathway remains undefined. Curcumol, a natural compound extracted from the Curcumae Rhizoma, has demonstrated anti-tumor and anti-inflammatory activities. Therefore, this study aimed to explore the potential of curcumol as a therapeutic agent for MI.

METHODS

Wild-type (WT) mice were administered with curcumol orally following left coronary artery ligation. The effects of curcumol on post-MI inflammatory responses were evaluated through phenotypic analysis, histology, and flow cytometry. RNA sequencing, surface plasmon resonance (SPR), and molecular docking were utilized to identify the molecular target of curcumol. Functional studies were further conducted using stimulator of interferon genes (STING) knockout (Sting-/-) mice.

RESULTS

Curcumol treatment improved the survival rate in mice following MI while enhancing cardiac function and mitigating adverse post-infarction ventricular remodeling. Transcriptomic analysis and SPR indicated curcumol directly bound to STING. Functional assays demonstrated that the cardio-protective effects of curcumol were mediated via STING, as these effects were diminished in Sting-/- mice. Mechanistically, curcumol disrupted STING-TBK1 interaction, suppressing downstream signaling activation and type I interferon responses. Notably, curcumol exhibited stronger inhibition of activated STING signaling in macrophages and superior cardioprotective effects compared to the STING inhibitor H-151.

CONCLUSION

Curcumol targets STING to suppress type I interferon responses, improving cardiac function post-MI. These findings highlight curcumol as a promising therapeutic candidate for MI treatment.

Identification of splenic IRF7 as a nanotherapy target for tele-conditioning myocardial reperfusion injury

The sequestration of nanoparticles by mononuclear phagocyte system is a challenge for the use of nanotherapy for treating cardiovascular diseases due to the conventionally perceived loss of therapeutic potency. Here, we revitalize cardiovascular nanotherapy by unlocking an alternative route in which nanomedicines are redirected to the spleen, leveraging its potential as a highly efficient and targeted site for remote conditioning, or tele-conditioning myocardial reperfusion injury. The theoretical foundation underpinning is the splenogenic nature of recruited monocytes upon myocardial reperfusion in the acute stage, which is confirmed through murine heterotopic spleen transplantation. Single-cell RNA-seq analysis identifies IRF7 as a pivotal mediator in the spleen-heart communication network that is initially induced in the spleen and orchestrates functional changes in myocardial macrophages. Spleen-related induction of IRF7 is also valid in human myocardial reperfusion scenarios. In addition, in a murine preclinical model of male mice, temporal inhibition of splenic IRF7 through the designed spleen-targeting erythrosome engineered with the targeting peptide RP182, termed as STEER nanoparticles, mitigates the acute-stage innate immune responses and improves the cardiac function in the long term. In contrast, systemic inhibition, genetic knockout of IRF7 or absolute depletion of splenic monocytes does not have therapeutic benefits, indicating the superiority of nanoparticle-based targeted treatment. These findings establish the spleen as a naturally favored site for nanoparticle-based treatments, offering promising avenues for managing myocardial reperfusion injury.

U-shaped association between plasma cyclic guanosine monophosphate-adenosine monophosphate (cGAMP) levels and myocardial infarction

BACKGROUND

The cyclic guanosine monophosphate-adenosine monophosphate synthase-stimulator of interferon genes (cGAS-STING) signaling pathway is closely associated with myocardial infarction (MI). Cyclic guanosine monophosphate-adenosine monophosphate (cGAMP) is a key component of this pathway; however, there is currently a lack of clinical evidence linking plasma cGAMP levels to MI.

METHODS

This study utilized clinical data from 270 patients diagnosed with coronary heart disease (CHD) at the Second Xiangya Hospital of Central South University. The outcomes included ST-segment elevation and non-ST-segment elevation MI. Univariate and multivariate logistic regression models were used to explore the relationships between plasma cGAMP levels and MI, while restricted cubic spline (RCS) using logistic regression to explore the dose-response relationship.

RESULTS

Among the 270 patients, the mean plasma cGAMP level was 1352.58 ± 106.02 ng/L and 89 (32.96%) patients were diagnosed with MI. The RCS curves indicated a U-shape association between the cGAMP levels and MI; the risk of MI was negatively correlated with the cGAMP until it hit bottoms at 1352 ng/L. When the cGAMP level exceeded 1352 ng/L, the risk of MI increased significantly (adjusted OR, 1.02; 95% CI: 1.01-1.03). When considering cGAMP as a categorical variable, patients in Tertile 1 and Tertile 3 had a 167% (adjusted OR: 2.67, 95% CI: 1.23-5.78) and 155% (adjusted OR: 2.55, 95% CI: 1.17-5.55) higher risk of MI compared to those in Tertile 2, respectively. These results were consistent across subgroup analyses, notably, a significant interaction by age category was observed in patients with cGAMP ≥ 1352 ng/L, where the positive association was pronounced in the elderly.

CONCLUSIONS

A U-shaped association exists between cGAMP and MI in the CHD population, with a cutoff point at the cGAMP of 1352 ng/L. Both excessively high and low cGAMP levels are associated with an increased risk of MI, particularly among the elderly with cGAMP ≥ 1352 ng/L. This is the first clinical evidence of the cGAS-cGAMP-STING pathway in metabolic cardiovascular diseases.

CLINICALTRIALS

GOV IDENTIFIER

NCT03363035 (Registration date: 2018-01-15).

Genetic Mapping of Monocyte Fate Decisions Following Myocardial Infarction

Inflammation contributes to the pathogenesis of myocardial infarction and heart failure and represents a viable therapeutic target. Monocytes and their progeny are highly abundant and display incredible functional diversity, serving as key determinants of myocardial inflammation and tissue repair. Much remains to be learned regarding mechanisms and signaling events that instruct monocyte fate decisions. We devised a genetic lineage tracing strategy using Ccr2 crERT2 Rosa26 LSL-tdTomato mice in combination with single cell RNA-sequencing to map the differentiation trajectories of monocytes that infiltrate the heart after reperfused myocardial infarction. Monocytes are recruited to the heart early after injury and give rise to transcriptionally distinct and spatially restricted macrophage and dendritic cell-like subsets that are specified prior to extravasation and chronically persist within the myocardium. Pseudotime analysis predicted two differentiation trajectories of monocyte-derived macrophages that are partitioned into the border and infarct zones, respectively. Among these trajectories, we show that macrophages expressing a type I IFN responsive signature are an intermediate population that gives rise to MHC-II hi macrophages, are localized within the border zone, and promote myocardial protection. Collectively, these data uncover new complexities of monocyte differentiation in the infarcted heart and suggest that modulating monocyte fate decisions may have clinical implications.

Dysregulation of Mitochondrial Homeostasis in Cardiovascular Diseases

Mitochondria dysfunction plays a central role in the development of vascular diseases as oxidative stress promotes alterations in mitochondrial morphology and function that contribute to disease progression. Redox imbalances can affect normal cellular processes including mitochondrial biogenesis, electrochemical equilibrium, and the regulation of mitochondrial DNA. In this review, we will discuss these imbalances and, in particular, the potential role of mitochondrial fusion, fission, biogenesis, and mitophagy in the context of vascular diseases and how the dysregulation of normal function might contribute to disease progression. We will also discuss potential implications of targeting mitochondrial regulation as therapeutic targets to treat vascular disease formation.

Infiltrating lipid-rich macrophage subpopulations identified as a regulator of increasing prostate size in human benign prostatic hyperplasia

Introduction

Macrophages exhibit marked phenotypic heterogeneity within and across disease states, with lipid metabolic reprogramming contributing to macrophage activation and heterogeneity. Chronic inflammation has been observed in human benign prostatic hyperplasia (BPH) tissues, however macrophage activation states and their contributions to this hyperplastic disease have not been defined. We postulated that a shift in macrophage phenotypes with increasing prostate size could involve metabolic alterations resulting in prostatic epithelial or stromal hyperplasia.

Methods

Single-cell RNA-seq of CD45+ transition zone leukocytes from 10 large (>90 grams) and 10 small (<40 grams) human prostates was conducted. Macrophage subpopulations were defined using marker genes and evaluated by flow cytometry.

Results

BPH macrophages do not distinctly categorize into M1 and M2 phenotypes. Instead, macrophages with neither polarization signature preferentially accumulate in large versus small prostates. Specifically, macrophage subpopulations with altered lipid metabolism pathways, demarcated by TREM2 and MARCO expression, accumulate with increased prostate volume. TREM2 high and MARCO high macrophage abundance positively correlates with patient body mass index and urinary symptom scores. TREM2high macrophages have a statistically significant increase in neutral lipid compared to TREM2low macrophages from BPH tissues. Lipid-rich macrophages were observed to localize within the stroma in BPH tissues. In vitro studies indicate that lipid-loaded macrophages increase prostate epithelial and stromal cell proliferation compared to control macrophages.

Discussion

These data define two new BPH immune subpopulations, TREM2high and MARCOhigh macrophages, and suggest that lipid-rich macrophages may exacerbate lower urinary tract symptoms in patients with large prostates. Further investigation is needed to evaluate the therapeutic benefit of targeting these cells in BPH.

Central SGLT2 mediate sympathoexcitation in hypertensive heart failure via attenuating subfornical organ endothelial cGAS ubiquitination to amplify neuroinflammation: Molecular mechanism behind sympatholytic effect of Empagliflozin

BACKGROUND

Sodium/glucose co-transporter 2 (SGLT2) inhibitors have transformed heart failure (HF) treatment, offering sympatholytic effects whose mechanisms are not fully understood. Our previous studies identified Cyclic GMP-AMP synthase (cGAS)-derived neuroinflammation in the Subfornical organ (SFO) as a promoter of sympathoexcitation, worsening myocardial remodeling in HF. This research explored the role of central SGLT2 in inducing endothelial cGAS-driven neuroinflammation in the SFO during HF and assessed the impact of SGLT2 inhibitors on this process.

METHODS

Hypertensive HF was induced in mice via Angiotensin II infusion for four weeks. SGLT2 expression and localization in the SFO were determined through immunoblotting and double-immunofluorescence staining. AAV9-TIE-shRNA (SGLT2) facilitated targeted SGLT2 knockdown in SFO endothelial cells (ECs), with subsequent analyses via immunoblotting, staining, and co-immunoprecipitation to investigate interactions with cGAS, mitochondrial alterations, and pro-inflammatory pathway activation. Renal sympathetic nerve activity and heart rate variability were measured to assess sympathetic output, alongside evaluations of cardiac function in HF mice.

RESULTS

In HF model mice, SGLT2 levels are markedly raised in SFO ECs, disrupting mitochondrial function and elevating oxidative stress. SGLT2 knockdown preserved mitochondrial integrity and function, reduced inflammation, and highlighted the influence of SGLT2 on mitochondrial health. SGLT2's interaction with cGAS prevented its ubiquitination and degradation, amplifying neuroinflammation and HF progression. Conversely, Empagliflozin counteracted these effects, suggesting that targeting the SGLT2-cGAS interaction as a novel HF treatment avenue.

CONCLUSION

This study revealed that SGLT2 directly reduced cGAS degradation in brain ECs, enhancing neuroinflammation in the SFO, and promoting sympathoexcitation and myocardial remodeling. The significance of the central SGLT2-cGAS interaction in cardiovascular disease mechanisms is emphasized.

Cardioprotective microRNAs (protectomiRs) in a pig model of acute myocardial infarction and cardioprotection by ischaemic conditioning: MiR-450a

BACKGROUND AND PURPOSE

Cardioprotective miRNAs (protectomiRs) are promising therapeutic tools. Here, we aimed to identify protectomiRs in a translational porcine model of acute myocardial infarction (AMI) and to validate their cardiocytoprotective effect.

EXPERIMENTAL APPROACH

ProtectomiR candidates were selected after systematic analysis of miRNA expression changes in cardiac tissue samples from a closed-chest AMI model in pigs subjected to sham operation, AMI and ischaemic preconditioning, postconditioning or remote preconditioning, respectively. Cross-species orthologue protectomiR candidates were validated in simulated ischaemia-reperfusion injury (sI/R) model of isolated rat ocardiomyocytes and in human AC16 cells as well. For miR-450a, we performed target prediction and analysed the potential mechanisms of action by GO enrichment and KEGG pathway analysis.

KEY RESULTS

Out of the 220 detected miRNAs, four were up-regulated and 10 were down-regulated due to all three conditionings versus AMI. MiR-450a and miR-451 mimics at 25 nM were protective in rat cardiomyocytes, and miR-450a showed protection in human cardiomyocytes as well. MiR-450a has 3987 predicted mRNA targets in pigs, 4279 in rats and 8328 in humans. Of these, 607 genes are expressed in all three species. A total of 421 common enriched GO terms were identified in all three species, whereas KEGG pathway analysis revealed 13 common pathways.

CONCLUSION AND IMPLICATIONS

This is the first demonstration that miR-450a is associated with cardioprotection by ischaemic conditioning in a clinically relevant porcine model and shows cardiocytoprotective effect in human cardiomyocytes, making it a promising drug candidate. The mechanism of action of miR-450a involves multiple cardioprotective pathways.

LINKED ARTICLES

This article is part of a themed issue Non-coding RNA Therapeutics. To view the other articles in this section visit http://onlinelibrary.wiley.com/doi/10.1111/bph.v182.2/issuetoc.

DNA sensors in metabolic and cardiovascular diseases: Molecular mechanisms and therapeutic prospects

DNA sensors generally initiate innate immune responses through the production of type I interferons. While extensively studied for host defense against invading pathogens, emerging evidence highlights the involvement of DNA sensors in metabolic and cardiovascular diseases. Elevated levels of modified, damaged, or ectopically localized self-DNA and non-self-DNA have been observed in patients and animal models with obesity, diabetes, fatty liver disease, and cardiovascular disease. The accumulation of cytosolic DNA aberrantly activates DNA signaling pathways, driving the pathological progression of these disorders. This review highlights the roles of specific DNA sensors, such as cyclic AMP-GMP synthase and stimulator of interferon genes (cGAS-STING), absent in melanoma 2 (AIM2), toll-like receptor 9 (TLR9), interferon gamma-inducible protein 16 (IFI16), DNA-dependent protein kinase (DNA-PK), and DEAD-box helicase 41 (DDX41) in various metabolic disorders. We explore how DNA signaling pathways in both immune and non-immune cells contribute to the development of these diseases. Furthermore, we discuss the intricate interplay between metabolic stress and immune responses, offering insights into potential therapeutic targets for managing metabolic and cardiovascular disorders. Understanding the mechanisms of DNA sensor signaling in these contexts provides a foundation for developing novel interventions aimed at mitigating the impact of these pervasive health issues.

Heart Failure Is Closely Associated With the Expression Characteristics of Type I Interferon-Related Genes

BACKGROUND

The association between the expression of type I interferon related genes (TIIRGs) and EFrHF is not well understood. This study aimed to investigate the correlation between the expression patterns of TIIRGs and EFrHF using bioinformatics analysis.

MATERIALS AND METHODS

An analysis was conducted to examine the expression and distribution of TIIRGs in cardiomyocytes. Afterwards, GSE5406 was utilized as the validation set, including 16 without heart failure, 86 with idiopathic dilated cardiomyopathy (IDCM), and 108 individuals with ischemic cardiomyopathy (ICM). We conducted a comparative analysis of the variations in TIIRGs gene expression across various forms of heart failure.

RESULTS

There were eight genes that showed substantial changes between patients with EFrHF and those without heart failure. A risk model for EFrHF was developed utilizing JAK1 and EIF2AK2, with an area under the curve (AUC) of 0.909. Five genes exhibited notable disparities between IDCM and ICM. Through multivariate analysis, it was shown that JAK1 and IFNA16/IFNA14 were identified as independent risk variables for distinguishing between the two pathogenic categories. The model, utilizing JAK1 and IFNA16/IFNA14, successfully differentiated between IDCM and ICM with an area under the curve (AUC) of 0.722. In the validation set GSE5406, the expression of JAK1 was dramatically downregulated, while EIF2AK2 was significantly upregulated in heart failure (HF) tissues. The model utilizing JAK1 and EIF2AK2 successfully differentiated between those with an illness and those without (AUC = 0.877).

CONCLUSIONS

The expression of TIIRGs is strongly associated with the presence and specific subtypes of HF in a pathological context.

A network dynamic nomogram for predicting overall survival and cancer-specific survival in patients with breast cancer liver metastases: an analysis based on the SEER database

The liver stands out as one of the most frequent sites for distant metastasis in breast cancer cases. However, effective risk stratification tools for patients with breast cancer liver metastases (BCLM) are still lacking. We identified BCLM patients from the SEER database spanning from 2010 to 2016. After meticulously filtering out cases with incomplete data, a total of 3179 patients were enrolled and randomly divided into training and validation cohorts at a ratio of 2:1. Leveraging comprehensive patient data, we constructed a nomogram through rigorous evaluation of a Cox regression model. Validation of the nomogram was conducted using a range of statistical measures, including the concordance index (C-index), calibration curves, time-dependent receiver operating characteristic curves, and decision curve analysis (DCA). Both univariable and multivariable analyses revealed significant associations between OS and CSS in BCLM patients and 14 variables, including age, race, and tumor stage, among others. Utilizing these pertinent variables, we formulated nomograms for OS and CSS prediction. Subsequent validation involved rigorous assessment using time-dependent ROC curves, decision curve analysis, C-index evaluations, and calibration curves. Our web-based dynamic nomogram represents a valuable tool for efficiently analyzing the clinical profiles of BCLM patients, thereby aiding in informed clinical decision-making processes.

Pathophysiology of Angiotensin II-Mediated Hypertension, Cardiac Hypertrophy, and Failure: A Perspective from Macrophages

Heart failure is a complex syndrome characterized by cardiac hypertrophy, fibrosis, and diastolic/systolic dysfunction. These changes share many pathological features with significant inflammatory responses in the myocardium. Among the various regulatory systems that impact on these heterogeneous pathological processes, angiotensin II (Ang II)-activated macrophages play a pivotal role in the induction of subcellular defects and cardiac adverse remodeling during the progression of heart failure. Ang II stimulates macrophages via its AT1 receptor to release oxygen-free radicals, cytokines, chemokines, and other inflammatory mediators in the myocardium, and upregulates the expression of integrin adhesion molecules on both monocytes and endothelial cells, leading to monocyte-endothelial cell-cell interactions. The transendothelial migration of monocyte-derived macrophages exerts significant biological effects on the proliferation of fibroblasts, deposition of extracellular matrix proteins, induction of perivascular/interstitial fibrosis, and development of hypertension, cardiac hypertrophy and heart failure. Inhibition of macrophage activation using Ang II AT1 receptor antagonist or depletion of macrophages from the peripheral circulation has shown significant inhibitory effects on Ang II-induced vascular and myocardial injury. The purpose of this review is to discuss the current understanding in Ang II-induced maladaptive cardiac remodeling and dysfunction, particularly focusing on molecular signaling pathways involved in macrophages-mediated hypertension, cardiac hypertrophy, fibrosis, and failure. In addition, the challenges remained in translating these findings to the treatment of heart failure patients are also addressed.

Macrophages suppress cardiac reprogramming of fibroblasts in vivo via IFN-mediated intercellular self-stimulating circuit

Direct conversion of cardiac fibroblasts (CFs) to cardiomyocytes (CMs) in vivo to regenerate heart tissue is an attractive approach. After myocardial infarction (MI), heart repair proceeds with an inflammation stage initiated by monocytes infiltration of the infarct zone establishing an immune microenvironment. However, whether and how the MI microenvironment influences the reprogramming of CFs remains unclear. Here, we found that in comparison with cardiac fibroblasts (CFs) cultured in vitro, CFs that transplanted into infarct region of MI mouse models resisted to cardiac reprogramming. RNA-seq analysis revealed upregulation of interferon (IFN) response genes in transplanted CFs, and subsequent inhibition of the IFN receptors increased reprogramming efficiency in vivo. Macrophage-secreted IFN-β was identified as the dominant upstream signaling factor after MI. CFs treated with macrophage-conditioned medium containing IFN-β displayed reduced reprogramming efficiency, while macrophage depletion or blocking the IFN signaling pathway after MI increased reprogramming efficiency in vivo. Co-IP, BiFC and Cut-tag assays showed that phosphorylated STAT1 downstream of IFN signaling in CFs could interact with the reprogramming factor GATA4 and inhibit the GATA4 chromatin occupancy in cardiac genes. Furthermore, upregulation of IFN-IFNAR-p-STAT1 signaling could stimulate CFs secretion of CCL2/7/12 chemokines, subsequently recruiting IFN-β-secreting macrophages. Together, these immune cells further activate STAT1 phosphorylation, enhancing CCL2/7/12 secretion and immune cell recruitment, ultimately forming a self-reinforcing positive feedback loop between CFs and macrophages via IFN-IFNAR-p-STAT1 that inhibits cardiac reprogramming in vivo. Cumulatively, our findings uncover an intercellular self-stimulating inflammatory circuit as a microenvironmental molecular barrier of in situ cardiac reprogramming that needs to be overcome for regenerative medicine applications.

Exosomes from human bone marrow MSCs alleviate PD-1/PD-L1 inhibitor-induced myocardial injury in melanoma mice by regulating macrophage polarization and pyroptosis

Myocarditis, which can be triggered by immune checkpoint inhibitor (ICI) treatment, represents a critical and severe adverse effect observed in cancer therapy. Thus, elucidating the underlying mechanism and developing effective strategies to mitigate its harmful impact is of utmost importance. The objective of this study is to investigate the potential role and regulatory mechanism of exosomes derived from human bone marrow mesenchymal stem cells (hBMSC-Exos) in providing protection against myocardial injury induced by ICIs. We observed that the administration of programmed death 1/programmed death-ligand 1 (PD-1/PD-L1) inhibitor BMS-1 in tumor-bearing mice led to evident cardiac dysfunction and myocardial injury, which were closely associated with M1 macrophage polarization and cardiac pyroptosis. Remarkably, these adverse effects were significantly alleviated through tail-vein injection of hBMSC-Exos. Moreover, either BMS-1 or hBMSC-Exos alone demonstrated the ability to reduce tumor size, while the combination of hBMSC-Exos with BMS-1 treatment not only effectively improved the probability of tumor inhibition but also alleviated cardiac anomalies induced by BMS-1.

Comprehensive macro and micro views on immune cells in ischemic heart disease

Ischemic heart disease (IHD) is a prevalent cardiovascular condition that remains the primary cause of death due to its adverse ventricular remodelling and pathological changes in end-stage heart failure. As a complex pathologic condition, it involves intricate regulatory processes at the cellular and molecular levels. The immune system and cardiovascular system are closely interconnected, with immune cells playing a crucial role in maintaining cardiac health and influencing disease progression. Consequently, alterations in the cardiac microenvironment are influenced and controlled by various immune cells, such as macrophages, neutrophils, dendritic cells, eosinophils, and T-lymphocytes, along with the cytokines they produce. Furthermore, studies have revealed that Gata6+ pericardial cavity macrophages play a key role in regulating immune cell migration and subsequent myocardial tissue repair post IHD onset. This review outlines the role of immune cells in orchestrating inflammatory responses and facilitating myocardial repair following IHD, considering both macro and micro views. It also discusses innovative immune cell-based therapeutic strategies, offering new insights for further research on the pathophysiology of ischemic heart disease and immune cell-targeted therapy for IHD.

Deletion of stimulator of interferons genes aggravated cardiac dysfunction in physiological aged mice

BACKGROUND

Stimulator of interferons genes (STING) is crucial for innate immune response. It has been demonstrated that cGAS-STING pathway was the driver of aging-related inflammation. However, whether STING is involved in cardiac dysfunction during the physiological aging process remains unclear.

METHODS

Gene expression profiles were obtained from the Gene Expression Omnibus database, followed by weighted gene co-expression network analysis, gene ontology analysis and protein network interaction analysis to identify key pathway and genes associated with aging. The effects of STING on cardiac function, glucose homeostasis, inflammation, and autophagy in physiological aging were investigated with STING knockout mice.

RESULTS

Bioinformatics analysis revealed STING emerged as a hub gene of interest. Subsequent experiments demonstrated the activation of STING pathway in the heart of aged mice. Knockout of STING alleviated the inflammation in aged mice. However, Knockout of STING impaired glucose tolerance, inhibited autophagy, enhanced oxidative stress and aggravated cardiac dysfunction in aged mice.

CONCLUSION

Although reducing inflammation, long-term STING inhibition by genetic ablation exacerbated cardiac dysfunction in aged mice. Given the multifaceted nature of aging and the diverse cellular functions of STING beyond immune regulation, the negative effects of targeting STING as a strategy to mitigate aging phenotype should be fully considered.

Unraveling the cGAS/STING signaling mechanism: impact on glycerolipid metabolism and diseases

The cyclic GMP-AMP synthase (cGAS) and its downstream effector, the stimulator of interferon genes (STING), are crucial components of the innate immune response, traditionally recognized for their role in detecting cytosolic DNA from pathogens and damaged host cells. However, recent research indicates that the cGAS-STING pathway also significantly impacts metabolic processes, particularly glycerolipid metabolism. Glycerolipids are essential for energy storage and cellular membrane integrity, and their dysregulation is linked to metabolic disorders such as obesity, insulin resistance, and non-alcoholic fatty liver disease (NAFLD). Both cGAS and STING are expressed in various metabolic tissues, suggesting a potential role in lipid homeostasis. Chronic activation of the cGAS-STING pathway may promote inflammatory states that exacerbate insulin resistance and lipid accumulation, forming a feedback loop of metabolic dysfunction. This review explores the emerging relationship between cGAS/STING signaling and glycerolipid metabolism, discussing the mechanisms through which this pathway influences lipid regulation and the potential for therapeutic interventions. By integrating insights from immunology and metabolism, we aim to provide a comprehensive understanding of how the cGAS-STING axis may serve as a novel target for addressing metabolic disorders and enhancing metabolic health outcomes.

Catecholamine-Induced Inflammasome Activation in the Heart Following Photothrombotic Stroke

Cerebrovascular stroke patients exhibit an increased incidence of cardiac arrhythmias. The pathomechanisms underlying post-traumatic cardiac dysfunction include a surge of catecholamines and an increased systemic inflammatory response, but whether inflammasome activation contributes to cardiac dysfunction remains unexplored. Here, we used a mouse model of photothrombotic stroke (PTS) to investigate the role of inflammasome activation in post-stroke cardiac dysfunction by catecholamines and to evaluate the effectiveness of the inflammasome inhibitor IC100 on inflammasome activation. To evaluate functional electrophysiological changes in the heart by catecholamine treatment, we recorded action potential duration in excised zebrafish hearts with and without IC100 treatment. We show that PTS induced AIM2 inflammasome activation in atria and ventricles that was significantly reduced by administration of IC100. Injection of epinephrine into naïve mice induced a significant increase in AIM2, IL-1b and caspase-8 in atria. Treatment of excised zebrafish hearts with epinephrine shortened the action potential duration and this shortening that was reduced by IC100. These findings indicate that stroke initiates a catecholamine surge that induces inflammasome activation and pyroptosis in the heart that is blocked by IC100, thus providing a framework for the development of therapeutics for stroke-related cardiovascular injury.

Association between RDW-SD and prognosis across glycemic status in patients with dilated cardiomyopathy

INTRODUCTION

The prognostic significance of red cell distribution width-SD (RDW-SD) as a promising inflammatory biomarker in individuals with non-ischemic dilated cardiomyopathy (DCM) and varying glycemic status remains unexplored.

RESEARCH DESIGN AND METHODS

Patients hospitalized for DCM in Fuwai Hospital from 2006 to 2021 were retrospectively included. The primary outcome encompassed all-cause mortality and heart transplantations. The multivariable Cox regression was used to evaluate the association between RDW-SD and outcomes in the overall DCM population, and among patients with normoglycemia (NG), pre-diabetes mellitus (pre-DM) and DM.

RESULTS

Among 1,102 patients with DCM, the median age was 48 years and 23.5% were women. In the overall DCM cohort, the RDW-SD was independently associated with the primary outcome (adjusted HR 1.29, 95% CI 1.15 to 1.45, p<0.001, per SD increase). When stratifying patients with glycemic status, the RDW-SD exhibited an independent association with outcome in patients with DCM with pre-DM and DM, the adjusted HRs were 1.48 (95% CI 1.21 to 1.79, p<0.001) and 1.30 (95% CI 1.06 to 1.60, p=0.011) per SD increase, respectively. However, in patients with DCM and NG, the prognostic value of RDW-SD was insignificant, with an adjusted HR of 1.20 per SD increase (95% CI: 0.97 to 1.48, p=0.101).

CONCLUSIONS

RDW-SD was independently associated with the outcome in patients with DCM with pre-DM and DM, suggesting potential individualized therapeutic targets for this subset of patients with DCM.

Single-Cell RNA Sequencing Reveals Metabolic Stress-Dependent Activation of Cardiac Macrophages in a Model of Dyslipidemia-Induced Diastolic Dysfunction

BACKGROUND

Metabolic distress is often associated with heart failure with preserved ejection fraction (HFpEF) and represents a therapeutic challenge. Metabolism-induced systemic inflammation links comorbidities with HFpEF. How metabolic changes affect myocardial inflammation in the context of HFpEF is not known.

METHODS

We found that ApoE knockout mice fed a Western diet recapitulate many features of HFpEF. Single-cell RNA sequencing was used for expression analysis of CD45+ cardiac cells to evaluate the involvement of inflammation in diastolic dysfunction. We focused bioinformatics analysis on macrophages, obtaining high-resolution identification of subsets of these cells in the heart, enabling us to study the outcomes of metabolic distress on the cardiac macrophage infiltrate and to identify a macrophage-to-cardiomyocyte regulatory axis. To test whether a clinically relevant sodium glucose cotransporter-2 inhibitor could ameliorate the cardiac immune infiltrate profile in our model, mice were randomized to receive the sodium glucose cotransporter-2 inhibitor dapagliflozin or vehicle for 8 weeks.

RESULTS

ApoE knockout mice fed a Western diet presented with reduced diastolic function, reduced exercise tolerance, and increased pulmonary congestion associated with cardiac lipid overload and reduced polyunsaturated fatty acids. The main immune cell types infiltrating the heart included 4 subpopulations of resident and monocyte-derived macrophages, determining a proinflammatory profile exclusively in ApoE knockout-Western diet mice. Lipid overload had a direct effect on inflammatory gene activation in macrophages, mediated through endoplasmic reticulum stress pathways. Investigation of the macrophage-to-cardiomyocyte regulatory axis revealed the potential effects on cardiomyocytes of multiple inflammatory cytokines secreted by macrophages, affecting pathways such as hypertrophy, fibrosis, and autophagy. Finally, we describe an anti-inflammatory effect of sodium glucose cotransporter-2 inhibition in this model.

CONCLUSIONS

Using single-cell RNA sequencing in a model of diastolic dysfunction driven by hyperlipidemia, we have determined the effects of metabolic distress on cardiac inflammatory cells, in particular on macrophages, and suggest sodium glucose cotransporter-2 inhibitors as potential therapeutic agents for the targeting of a specific phenotype of HFpEF.

The Macrophage-Fibroblast Dipole in the Context of Cardiac Repair and Fibrosis

Stromal and immune cells and their interactions have gained the attention of cardiology researchers and clinicians in recent years as their contribution in cardiac repair is increasingly recognized. The repair process in the heart is a particularly critical constellation of complex molecular and cellular events and interactions that characteristically fail to ensure adequate recovery following injury, insult, or exposure to stress conditions in this regeneration-hostile organ. The tremendous consequence of this pronounced inability to maintain homeostatic states is being translated in numerous ways promoting progress into heart failure, a deadly, irreversible condition requiring organ transplantation. Fibrosis is in fact a repair response eventually promoting cardiac dysfunction and cardiac fibroblasts are the major cellular players in this process, overproducing collagens and other extracellular matrix components when activated. On the other hand, macrophages may differentially affect fibroblasts and cardiac repair depending on their status and subsets. The opposite interaction is also probable. We discuss here the multifaceted aspects and crosstalk of this cell dipole and the opportunities it may offer for beneficial manipulation approaches that will hopefully lead to progress in heart disease interventions.

Macrophage-mediated heart repair and remodeling: A promising therapeutic target for post-myocardial infarction heart failure

Heart failure (HF) remains prevalent in patients who survived myocardial infarction (MI). Despite the accessibility of the primary percutaneous coronary intervention and medications that alleviate ventricular remodeling with functional improvement, there is an urgent need for clinicians and basic scientists to further reveal the mechanisms behind post-MI HF as well as investigate earlier and more efficient treatment after MI. Growing numbers of studies have highlighted the crucial role of macrophages in cardiac repair and remodeling following MI, and timely intervention targeting the immune response via macrophages may represent a promising therapeutic avenue. Recently, technology such as single-cell sequencing has provided us with an updated and in-depth understanding of the role of macrophages in MI. Meanwhile, the development of biomaterials has made it possible for macrophage-targeted therapy. Thus, an overall and thorough understanding of the role of macrophages in post-MI HF and the current development status of macrophage-based therapy will assist in the further study and development of macrophage-targeted treatment for post-infarction cardiac remodeling. This review synthesizes the spatiotemporal dynamics, function, mechanism and signaling of macrophages in the process of HF after MI, as well as discusses the emerging bio-materials and possible therapeutic agents targeting macrophages for post-MI HF.

Autoimmune diseases and atherosclerotic cardiovascular disease

Autoimmune diseases are associated with a dramatically increased risk of atherosclerotic cardiovascular disease and its clinical manifestations. The increased risk is consistent with the notion that atherogenesis is modulated by both protective and disease-promoting immune mechanisms. Notably, traditional cardiovascular risk factors such as dyslipidaemia and hypertension alone do not explain the increased risk of cardiovascular disease associated with autoimmune diseases. Several mechanisms have been implicated in mediating the autoimmunity-associated cardiovascular risk, either directly or by modulating the effect of other risk factors in a complex interplay. Aberrant leukocyte function and pro-inflammatory cytokines are central to both disease entities, resulting in vascular dysfunction, impaired resolution of inflammation and promotion of chronic inflammation. Similarly, loss of tolerance to self-antigens and the generation of autoantibodies are key features of autoimmunity but are also implicated in the maladaptive inflammatory response during atherosclerotic cardiovascular disease. Therefore, immunomodulatory therapies are potential efficacious interventions to directly reduce the risk of cardiovascular disease, and biomarkers of autoimmune disease activity could be relevant tools to stratify patients with autoimmunity according to their cardiovascular risk. In this Review, we discuss the pathophysiological aspects of the increased cardiovascular risk associated with autoimmunity and highlight the many open questions that need to be answered to develop novel therapies that specifically address this unmet clinical need.

Mitochondrial metabolism regulated macrophage phenotype in myocardial infarction

Cardiovascular disease (CVD) remains the leading cause of death worldwide, with myocardial infarction (MI) being the primary contributor to mortality and disability associated with CVD. Reperfusion therapies are widely recognized as effective strategies for treating MI. However, while intended to restore blood flow, the reperfusion processes paradoxically initiate a series of pathophysiological events that worsen myocardial injury, resulting in ischemia-reperfusion (I/R) injury. Therefore, there is a pressing need for new treatment strategies to reduce the size of MI and enhance cardiac function post-infarction. Macrophages are crucial for maintaining homeostasis and mitigating undesirable remodeling following MI. Extensive research has established a strong link between cellular metabolism and macrophage function. In the context of MI, macrophages undergo adaptive metabolic reprogramming to mount an immune response. Moreover, mitochondrial metabolism in macrophages is evident, leading to significant changes in their metabolism. Therefore, we need to delve deeper into summarizing and understanding the relationship and role between mitochondrial metabolism and macrophage phenotype, and summarize existing treatment methods. In this review, we explore the role of mitochondria in shaping the macrophage phenotype and function. Additionally, we summarize current therapeutic strategies aimed at modulating mitochondrial metabolism of macrophages, which may offer new insights treating of MI.

TBK1-Zyxin signaling controls tumor-associated macrophage recruitment to mitigate antitumor immunity

Mechanical control is fundamental for cellular localization within a tissue, including for tumor-associated macrophages (TAMs). While the innate immune sensing pathways cGAS-STING and RLR-MAVS impact the pathogenesis and therapeutics of malignant diseases, their effects on cell residency and motility remain incompletely understood. Here, we uncovered that TBK1 kinase, activated by cGAS-STING or RLR-MAVS signaling in macrophages, directly phosphorylates and mobilizes Zyxin, a key regulator of actin dynamics. Under pathological conditions and in STING or MAVS signalosomes, TBK1-mediated Zyxin phosphorylation at S143 facilitates rapid recruitment of phospho-Zyxin to focal adhesions, leading to subsequent F-actin reorganization and reduced macrophage migration. Intratumoral STING-TBK1-Zyxin signaling was evident in TAMs and critical in antitumor immunity. Furthermore, myeloid-specific or global disruption of this signaling decreased the population of CD11b+ F4/80+ TAMs and promoted PD-1-mediated antitumor immunotherapy. Thus, our findings identify a new biological function of innate immune sensing pathways by regulating macrophage tissue localization, thus providing insights into context-dependent mitigation of antitumor immunity.