Introduction Inflammation plays a central role in atherosclerosis development and subsequent cardiovascular complications, including heart attack and stroke. Patients with inflammatory conditions such as community-acquired pneumonia (CAP) present with an elevated risk of cardiovascular events, which is likely driven by unresolved systemic inflammation. Targeting this heightened inflammatory burden may present a novel therapeutic strategy to attenuate heart attack risk in CAP survivors. Icosapent ethyl (IPE), an omega-3 fatty acid, demonstrates both pro-resolving and cardioprotective properties. The Targeting Vascular Inflammation In Patients with CAP (TIN-CAP) trial aims to evaluate the efficacy of IPE in mitigating vascular inflammation in CAP survivors.Methods and analysis TIN-CAP is a multicentre, randomised, double-blind, placebo-controlled trial. Eligible adults diagnosed with CAP in hospital or the emergency department will complete baseline assessments within 14 days of diagnosis including 18F-fluorodeoxyglucose (FDG) positron emission tomography/CT angiography, bloodwork and quality of life evaluation (EuroQol – 5 Dimensions (EQ-5D)). Participants will then be randomised 1:1 to receive IPE (4 g/day) or placebo for 6 months. Follow-up visits will occur at 30 days (bloodwork and EQ-5D only) and 6 months. The primary endpoint is the change in FDG uptake in the ascending aorta from baseline to 6 months between IPE and placebo groups. Secondary endpoints include FDG uptake in the bone marrow, spleen, lungs and other vasculature, in addition to major adverse cardiac events and quality of life assessments. An initial lead-in cohort of 18 patients will be enrolled to assess recruitment, imaging feasibility and IPE tolerability prior to full trial enrolment. These patients will remain blinded and will be included in the final analysis (Vanguard design).Ethics and dissemination The TIN-CAP trial has been approved provincially by the Clinical Trials Ontario Research Ethics Board (approval number: 5045). Participants will provide written informed consent prior to enrolment. Study findings will be disseminated through peer-reviewed publications and conference presentations.Trial registration number NCT06710080.

Cytosolic lipid droplets (LDs) regulate lipid homeostasis, with abnormal LD dynamics linked to metabolic diseases like atherosclerosis. In macrophage foam cells, LDs undergo autophagic degradation via lipophagy, but the extent of this process in vascular smooth muscle cell (VSMC) foam cells remains unclear. To track lipophagy in real time, we developed a Rosella-PLIN2 (perilipin 2) biosensor by tagging PLIN2 with the fluorescent pH-biosensor Rosella. We show that proatherogenic lipoproteins and autophagy activators stimulate lipophagy in human macrophages. Targeting LDs with an LC3 fusion protein or LD-autophagy tethering compounds (LD-ATTECs) selectively enhanced lipophagy, promoting foam cell LD clearance. In an atherosclerosis model, Rosella-PLIN2 accurately tracked lipophagy in arterial foam cells, revealing distinct PLIN2 expression patterns in macrophage and non-leukocyte foam cells. We identified a lipophagy deficiency in VSMC foam cells and demonstrate that enhancing lipophagy promotes LD catabolism in primary VSMC foam cells. TREM2+ macrophages exhibited high lipid content and low lipophagy flux, whereas TREM2- macrophages had low lipid content and high lipophagy flux. Our findings highlight a cell-specific interplay between lipophagy and immunometabolism in arterial foam cells, unveiling novel therapeutic avenues for atherosclerosis. Additionally, the Rosella-PLIN2 model provides a powerful tool for studying LD metabolism, offering new insights into lipid homeostasis and disease mechanisms.Abbreviations: AgLDL: aggregated LDL; Baf-A1: bafilomycin A1; BMDMs: bone marrow-derived macrophages; HDL: high-density lipoproteins; LD: lipid droplets; LD-ATTECs: LD-autophagy tethering compounds; LDL: low-density lipoproteins; LIPA/LAL: lysosomal acid lipase A; LPS: lipopolysaccharide; MAP1LC3/LC3: microtubule-associated protein 1 light chain 3; LTA: lipoteichoic acid; MFI: mean fluorescence intensity; OA: oleic acid; p-ATG16L1: phospho-ATG16L1; PLIN2: perilipin 2; PLINs: perilipins; RCT: reverse cholesterol transport; TLR: toll-like receptor; VSMCs: vascular smooth muscle cells; WSC: water-soluble cholesterol.

Cardiovascular disease remains the leading cause of death worldwide, with a rising burden projected over the coming decades. Although traditional risk factors such as diabetes, hypertension, and dyslipidemia form the main targets of prevention strategies, many individuals carry a "residual" risk secondary to systemic inflammation which remains underrecognized. Landmark trials have established inflammation as a causal and modifiable driver of atherosclerotic cardiovascular disease. This review focuses on how inflammation can modulate interconnected diseases of the brain and heart. Growing evidence suggests that inflammation mediates a "brain-heart" axis, linking psychological stress, neuroinflammation, and cardiovascular pathology. Observational and mechanistic studies demonstrate that stress-induced neural activity, particularly within the amygdala, is associated with hematopoietic activation, arterial inflammation, and increased cardiovascular events. Models such as Takotsubo's cardiomyopathy and stroke-heart syndrome illustrate how acute brain injury can precipitate cardiovascular dysfunction via autonomic and inflammatory pathways. More recently, molecular imaging studies have provided direct evidence of stress-associated amygdalar activity being associated with both cardiovascular outcomes and cancer prognosis. This emerging framework reframes the brain and heart as interdependent organs connected through inflammatory and neurobiological processes, highlighting the potential for novel therapeutic targets, including modulation of stress-related neural pathways, alongside established anti-inflammatory strategies. Future directions include refinement of targeted therapies, use of advanced molecular imaging, and mechanistic studies to better delineate the pathways linking stress, inflammation, and cardiovascular disease.

BACKGROUND:Aging is a well-established risk factor for the development and progression of atherosclerosis, but the molecular mechanisms underlying this relationship remain poorly defined, and its role in atherosclerosis regression is unknown. To uncover age-related alterations that may impair atherosclerosis regression, we investigated the response of young and old macrophages to atherogenic lipoproteins in vitro and in vivo.METHODS:Metabolic and proteomic studies were performed in vitro using macrophages differentiated from the bone marrow of young or old mice. To test the role of immune cell aging in atherosclerosis regression, bone marrow from young and old donors was transplanted into irradiated young recipient mice expressing gain-of-function AAV-PCSK9 (adeno-associated virus-proprotein convertase subtilisin/kexin type 9). Following 14 weeks of Western diet feeding, atherosclerosis regression was induced by switching to a standard laboratory diet for 4 weeks.RESULTS:Compared with young macrophages, old macrophages accumulated more lipid droplets upon lipid loading with the pro-atherogenic lipoprotein aggregated LDL (low-density lipoprotein), accompanied by a failure to proportionally induce autophagy and cholesterol efflux. Proteomic analysis of bone marrow-derived macrophages revealed that pathways related to endocytosis, engulfment, and phagocytosis were downregulated in old lipid-loaded macrophages. Functional studies confirmed a reduction in efferocytic capacity in old macrophages. In recipient mice transplanted with old bone marrow, atherosclerosis regression was impaired, as evidenced by inefficient resolution of circulating inflammatory cell levels, reduced activation of plaque autophagy and apoptotic cell clearance, and persistent plaque CD45+ and CD68+ content.CONCLUSIONS:Aging impairs macrophage function through reduced efferocytosis and autophagy activation, limiting atherosclerosis regression. These results highlight the need to better define the mechanisms linking aging to atherosclerosis to develop targeted therapies for the aging population.

Background and aimsDysregulated cholesterol metabolism is a hallmark of atherosclerotic cardiovascular diseases, yet our understanding of how endogenous cholesterol synthesis affects atherosclerosis is not clear. The energy sensor AMP-activated protein kinase (AMPK) phosphorylates and inhibits the rate-limiting enzyme in the mevalonate pathway HMG-CoA reductase (HMGCR). Recent work demonstrated that when AMPK-HMGCR signaling was compromised in an Apoe-/- model of hypercholesterolemia, atherosclerosis was exacerbated due to elevated hematopoietic stem and progenitor cell mobilization and myelopoiesis. We sought to validate the significance of the AMPK-HMGCR signaling axis in atherosclerosis using a non-germline hypercholesterolemia model with functional ApoE.MethodsMale and female HMGCR S871A knock-in (KI) mice and wild-type (WT) littermate controls were made atherosclerotic by intravenous injection of a gain-of-function Pcsk9D374Y-adeno-associated virus followed by high-fat and high-cholesterol atherogenic western diet feeding for 16 weeks.ResultsAMPK activation suppressed endogenous cholesterol synthesis in primary bone marrow-derived macrophages from WT but not HMGCR KI mice, without changing other parameters of cholesterol regulation. Atherosclerotic plaque area was unchanged between WT and HMGCR KI mice, independent of sex. Correspondingly, there were no phenotypic differences observed in hematopoietic progenitors or differentiated immune cells in the bone marrow, blood, or spleen, and no significant changes in systemic markers of inflammation. When lethally irradiated female mice were transplanted with KI bone marrow, there was similar plaque content relative to WT.ConclusionsGiven previous work, our study demonstrates the importance of preclinical atherosclerosis model comparison and brings into question the importance of AMPK-mediated control of cholesterol synthesis in atherosclerosis.

Background: Atherosclerosis occurs as lipid and immune cell rich plaques deposit within the arterial wall of the heart. These immune cells are produced from hematopoietic stem and progenitor cells (HSPCs) in the bone marrow (BM) and spleen, a process known as hematopoiesis that is dictated by their microenvironment, including endothelial cells (ECs). Objective: While others have shown adverse remodeling of BM ECs during atherogenesis, whether splenic ECs show a similar dysfunction leading to exacerbated hematopoiesis has not been described. Methods: We analyzed RNA sequencing data from chow fed C57Bl/6 mice and high cholesterol diet (HCD) fed Apoe -/- mouse BM and splenic ECs obtained from published studies, as well as our own. In vivo studies were performed in mice on an atherogenic background ( Apoe -/-& Ldlr -/-) fed a HCD for 4 to 16 weeks. Knockdown of the mixed lineage kinase domain-like protein ( Mlkl KD) was achieved by weekly administration of antisense oligonucleotides (ASOs) or scrambled control (50mg/kg sc.). In vitro studies were performed in primary mouse splenic ECs transfected with siRNA. Results: Pathway analysis revealed remarkable tissue-specific responses to an atherogenic milieu, including dysregulation of Lipid Metabolism, Endocytosis and Cell Death pathways in splenic ECs. Interestingly, we previously showed that the mixed lineage kinase domain-like protein (MLKL) regulates the endocytic trafficking of lipids and cell death in macrophages. Indeed using Mlkl KD Apoe -/- mice, transplantation of Mlkl -/- BM into Ldlr -/- mice or EC-specific Mlkl -/- Apoe -/- mice, we show that loss of MLKL drives myelopoiesis and plaque development through regulation of splenic ECs. Both in vivo and in vitro , silencing Mlkl in splenic but not BM ECs potently increased lipid content and disrupted endocytosis by an accumulation of the multivesicular body marker CHMP4B, which mirror the dysregulated pathways we identified above. Furthermore, co-culture with Mlkl KD splenic ECs increased HSPC activation (pStat5) and myeloid colony formation, an effect that was lost when ECs were pre-treated with the upstream endocytosis inhibitor Dynasore. Conclusions: In conclusion, we establish a novel role for MLKL in regulating the balance of HSPCs, specifically through preservation of splenic, but not BM, ECs that repress hematopoiesis, highlighting the importance of splenic lipid metabolism and endocytosis and its impact on atherogenesis.

Leveraging data from human datasets, together with mechanistic studies in cells and animals, Li et al. identified a new drug candidate for the antagonism of P2Y(6) signalling in foam cells that could prevent the development of atherosclerosis. Screening of human and mouse atherosclerotic datasets suggested that P2Y(6) expression in macrophages may play a role in disease progression, which was then investigated using macrophage-specific deletion of P2Y(6 )in a mouse model of atherosclerosis, the Ldlr-/- mouse. This led to the screening and identification of novel antagonist of P2Y(6) with potential therapeutic applications.

Background: A hallmark of advanced, rupture-prone atherosclerotic plaques is the presence of a necrotic core - a dense mass of pro-inflammatory and cellular debris. Traditionally, it has been thought that most of the foam cells within this core are derived from macrophages. However, recent advances in single cell technologies have revealed that vascular smooth muscle cells have the capacity to transdifferentiate into "macrophage-like foam cells", accounting for almost half of the cell content in advanced plaques. Our lab and others have discovered that a primary cause of the necrotic core is necroptotic cell death, where the mixed lineage kinase domain like pseudokinase MLKL is a key executioner of this process. While the contribution of necroptotic macrophage-derived foam cells to atherosclerotic lesion growth and instability has been fairly well-studied, the role of necroptotic vascular smooth muscle cell-derived foam cells in this process remains unclear. Hypothesis: MLKL regulates cell death differently in macrophages and vascular smooth muscle cells when challenged with pro-atherogenic stimuli. Methods and Results: Bone marrow-derived macrophages (BMDMs) and aortic vascular smooth muscle cells (VSMCs) were isolated from wildtype mice and treated with pro-atherogenic stimuli in the presence or absence of apoptotic and necroptotic inhibitors, zVAD and Necrostatin-1 (Nec1). BMDMs underwent cell death in response to treatment with oxLDL or LPS plus zVAD within 24 hours (as measured by LDH release and SYTOX assays) while VSMCs survive up to 72 hours. However, when VSMCs are treated with BMDM conditioned media in addition to pro-atherogenic stimuli, VSMCs begin to show higher relative rates of cell death compared to controls. Confocal microscopy and Western blots revealed that VSMCs treated with cell death ligands in conjunction with BMDM conditioned media showed an increase in relative expression of total and pMLKL- a hallmark of necroptosis, compared to VSMCs without conditioned media. Conclusions: Overall, this work suggests VSMCs are inherently resistant to necroptosis unless treated with conditioned media from BMDMs, which may suggest that macrophages have the capacity to prime necroptosis in VSMCs, likely via secreted factors.

Background/Objectives: Pneumonia is inflammation of the lungs caused by an infection. Recent studies show an association between pneumonia and an increased risk of a heart attack. This is likely caused by the persistent inflammatory burden in the lungs and arterial vasculature even 30-45 days after clearance of the infection. Therefore, as inflammation is a strong contributor to the progression of atherosclerosis, there is a need to address the persistent inflammatory burden in this patient population. A normal course of inflammation begins with an initial pro-inflammatory phase and ends with a resolution phase, which is marked by tissue return to homeostasis. During pneumonia, resolution pathways are impaired. Returning resolution processes to normal functioning may prove to be an effective strategy to attenuate prolonged pneumonia-associated inflammation. Resolution pathways are mediated by fatty acid derivatives termed specialized pro-resolving lipid mediators (SPMs), the metabolites of poly-unsaturated fatty acids such as eicosapentaenoic acid (EPA). To improve the therapeutic impact, EPA can be encapsulated in nanoparticle carriers to increase bioavailability and therapeutic delivery. We hypothesize that delivery of EPA nanoparticles into the lungs will control the persistent inflammatory response following pneumonia and reduce atherosclerotic burden. Results: Bone-marrow derived macrophages (mouse) stimulated with gram-positive toxins and EPA-nanoparticles demonstrated reduced expression of pro-inflammatory markers measured using ELISA. We have also developed a mouse model of atherosclerosis combined with S. pneumoniae lung infection. Without EPA administration, S.pneumoniae infection followed by 8 weeks on a high fat diet resulted in a trend towards increased plaque size and lesion lipid content. We are currently evaluating if our EPA-nanoparticles promote resolution processes in the S.pneumoniae mouse model. Clinical Impact: We believe that promotion of resolution pathways via increasing SPM production will prove to be an effective strategy to address inflammation during pneumonia while reducing the risk of suppressive effects on the immune system often caused by currently prescribed anti-inflammatories.

Gene ontology features in fibrotic vs. non-fibrotic human ovaries

Pneumonia is inflammation in the lungs, which is usually caused by an infection. The symptoms of pneumonia can vary from mild to life-threatening, where severe illness is often observed in vulnerable populations like children, older adults, and those with preexisting health conditions. Vaccines have greatly reduced the burden of some of the most common causes of pneumonia, and the use of antimicrobials has greatly improved the survival to this infection. However, pneumonia survivors do not return to their preinfection health trajectories but instead experience an accelerated health decline with an increased risk of cardiovascular disease. The mechanisms of this association are not well understood, but a persistent dysregulated inflammatory response post-pneumonia appears to play a central role. It is proposed that the inflammatory response during pneumonia is left unregulated and exacerbates atherosclerotic vascular disease, which ultimately leads to adverse cardiac events such as myocardial infarction. For this reason, there is a need to better understand the inflammatory cross talk between the lungs and the heart during and after pneumonia to develop therapeutics that focus on preventing pneumonia-associated cardiovascular events. This review will provide an overview of the known mechanisms of inflammation triggered during pneumonia and their relevance to the increased cardiovascular risk that follows this infection. We will also discuss opportunities for new clinical approaches leveraging strategies to promote inflammatory resolution pathways as a novel therapeutic target to reduce the risk of cardiac events post-pneumonia.

Non-significant alteration in the immune and stromal landscape of the ovarian cortex with metformin use.

Automated microdissection and immunohistochemical analysis of the human ovarian cortex.

Differential gene expression in non-fibrotic, fibrotic, and metformin ovaries with samples from women taking gliptins omitted.

Gene annotations used to generate cell type scores

Grouped Nanostring data with gliptin samples omitted.

Gene ontology features in metformin vs. fibrotic human ovaries

The differentiation and activation of macrophages are critical regulatory programs that are central to host inflammation and pathogen defense. However, the transcriptional regulatory pathways involved in these programs are not well understood. Herein, we demonstrate that the activity and expression of the transcription factor ATF2 is precisely regulated during primary human monocyte-to-macrophage differentiation and that its activation is linked to M1 polarization and antibacterial responses. Genetic perturbation experiments demonstrated that deletion of ATF2 (THP-ΔATF2) resulted in irregular and abnormal macrophage morphology, whereas macrophages overexpressing ATF2 (THP-ATF2) developed round and pancake-like morphology, resembling classically activated (M1) macrophages. Mechanistically, we show that ATF2 binds to the core promoter of PPM1A, a phosphatase that regulates monocyte-to-macrophage differentiation, to regulate its expression. Functionally, overexpression of ATF2 sensitized macrophages to M1 polarization, resulting in increased production of major histocompatibility complex class II, IL-1β, and IP-10; improved phagocytic capacity; and enhanced control of the intracellular pathogen Mycobacterium tuberculosis. Gene expression profiling revealed that overexpression of ATF2 reprogramed macrophages to promote antibacterial pathways enriched in chemokine signaling, metabolism, and antigen presentation. Consistent with pathways analysis, metabolic profiling revealed that genetic overexpression or stimuli-induced activation of ATF2 alters the metabolic capacity of macrophages and primes these cells for glycolytic metabolism during M1 polarization or bacterial infection. Our findings reveal that ATF2 plays a central role during macrophage differentiation and M1 polarization to enhance the functional capacities of macrophages.