Blocking a Single Kinase May Steer Immune Cells Toward Safer Atherosclerotic Plaques

Cardiovascular disease remains the leading cause of death worldwide, and at the center of most heart attacks and strokes lies a deceptively simple biological event: the rupture of an atherosclerotic plaque. These fatty deposits build up silently inside artery walls over decades, and their stability, far more than their sheer size, determines whether a patient lives a normal life or suffers a catastrophic vascular event. Now, new research published in Experimental & Molecular Medicine points to an unexpected player in this process, a signaling enzyme called protein kinase C delta, whose absence appears to reprogram the behavior of macrophages, the immune cells that populate plaques, in ways that reduce a dangerous form of inflammatory cell death and help keep plaques structurally sound.

The study, titled ‘Deficiency of protein kinase Cδ reprograms macrophage immunometabolism to suppress pyroptosis and stabilize atherosclerotic plaques,’ examines how removing this single kinase alters the metabolic machinery inside macrophages and, as a consequence, changes the inflammatory character of atherosclerotic lesions. The finding is notable because it links three areas that have usually been studied in isolation: kinase signaling, immunometabolism, and the inflammatory form of cell death known as pyroptosis. By connecting them, the work suggests that a pathway long associated with immune activation may instead be a liability in chronic vascular disease.

To understand why this matters, it helps to recall what macrophages do inside an artery wall. These cells are recruited to sites where low-density lipoprotein particles have accumulated beneath the endothelial lining. Once there, they engulf lipids, and in doing so they can become the foam cells that give early plaques their fatty appearance. But macrophages are not passive containers. They are metabolically active, decision-making cells whose internal fuel choices, whether to burn glucose rapidly through glycolysis, whether to rely on mitochondrial oxidative phosphorylation, whether to draw on fatty acid oxidation, shape the inflammatory signals they emit. A plaque dominated by pro-inflammatory macrophages tends to be rich in degradative enzymes and death signals, thinning its protective fibrous cap and raising the risk of rupture.

Pyroptosis is one of the most incendiary of those death signals. Unlike ordinary apoptosis, which quietly packages cellular debris for removal, pyroptosis is a lytic, inflammatory death driven by the activation of inflammasomes, multiprotein complexes that trigger caspase enzymes to cleave gasdermin proteins. Cleaved gasdermins form pores in the cell membrane, causing the cell to swell, burst, and spill its contents, including potent inflammatory messengers such as interleukin-1 family cytokines, into the surrounding tissue. Within a plaque, waves of pyroptotic macrophage death enlarge the necrotic core, weaken the fibrous cap, and promote the thrombus formation that turns a stable lesion into a clinical emergency.

Protein kinase C delta has long been recognized as a versatile signaling molecule in immune cells, participating in pathways that regulate activation, migration, and death decisions. The new research asked a direct question: what happens to macrophage behavior, and to atherosclerotic disease, when this kinase is missing? The answer, according to the study, is that deficiency of the kinase reprograms macrophage immunometabolism, shifting the internal metabolic set points of the cells in a direction that suppresses pyroptosis. In other words, without protein kinase C delta, macrophages appear to become less prone to the explosive inflammatory death that destabilizes plaques.

The concept of immunometabolic reprogramming is central to interpreting this result. Macrophages adopt broadly distinguishable metabolic profiles depending on their activation state, and these profiles are not merely byproducts of inflammation; they actively reinforce it. A glycolytic shift, for example, supports the rapid production of inflammatory mediators, while a more oxidative, mitochondrial-oriented metabolism tends to accompany reparative, tissue-tolerant behavior. By showing that removing protein kinase C delta rewrites these metabolic choices, the study positions the kinase as a kind of metabolic gatekeeper whose activity licenses the inflammatory, pyroptosis-prone phenotype in the plaque environment.

The downstream consequence reported in the work is plaque stabilization. In atherosclerosis research, stability is assessed through structural features: the thickness of the fibrous cap that separates the thrombogenic necrotic core from the bloodstream, the size of that necrotic core, the collagen content of the cap, and the burden of dead and dying cells within the lesion. A plaque that retains a thick cap, a modest necrotic core, and abundant collagen is far less likely to rupture than one riddled with pyroptotic debris. The finding that PKC delta deficiency suppresses pyroptosis and stabilizes plaques implies that the kinase contributes to precisely the features that make lesions dangerous, and that its removal tilts lesions toward a safer architecture.

These results arrive amid a broader reassessment of inflammation as a therapeutic target in cardiovascular medicine. Landmark clinical trials have already demonstrated that blunting inflammatory signaling, for instance through interleukin-1 beta blockade or colchicine treatment, reduces cardiovascular events in selected patients, validating the idea that the immune component of atherosclerosis is druggable. Against that backdrop, a kinase that governs whether plaque macrophages die inflammatory deaths is an attractive candidate for intervention, because it acts upstream of the terminal events, inflammasome activation, gasdermin pore formation, cytokine release, and necrotic core expansion, that directly damage plaque integrity.

At the same time, the study invites caution. Protein kinase C delta participates in many physiological processes beyond the plaque, including immune defense against infection, platelet function, and the regulation of cell survival in multiple tissues. Any therapeutic strategy aimed at inhibiting the kinase, or at exploiting the metabolic programs it controls, would need to weigh the benefit of calmer plaque macrophages against the risk of impairing the host responses that depend on this enzyme. Translating a reprogramming effect observed in experimental models into a safe clinical approach will require a detailed map of which downstream metabolic and inflammasome pathways mediate the protection, and whether those pathways can be targeted selectively.

Even so, the conceptual contribution is substantial. The work reframes atherosclerotic plaque stability not simply as a matter of lipid lowering, which remains the foundation of therapy, but as a matter of immune cell fate, decided by intracellular metabolic wiring that can be shifted by manipulating a single signaling node. If the findings hold up across models and, eventually, in human tissue, they suggest that future treatment could combine lipid management with agents that nudge plaque macrophages away from pyroptosis and toward a stable, reparative state. In a disease that kills millions each year largely through plaque rupture, teaching immune cells to keep their composure may prove to be one of the more consequential ideas in modern cardiovascular research.

Subject of Research: The role of protein kinase C delta deficiency in reprogramming macrophage immunometabolism to suppress pyroptosis and stabilize atherosclerotic plaques

Article Title: Deficiency of protein kinase Cδ reprograms macrophage immunometabolism to suppress pyroptosis and stabilize atherosclerotic plaques

Article References: Lien, C.-F., Chang, H.-Y., Yu, S.-H., Cho, R.-L., Chen, S.-J., Kuo, T.-T., Chong, P. C.-T., Ye, C.-H., Lin, F.-Y., Wu, W.-L., Lin, S.-H., Tsai, C.-S., & Lin, C.-S. (2026). Deficiency of protein kinase Cδ reprograms macrophage immunometabolism to suppress pyroptosis and stabilize atherosclerotic plaques. Experimental & Molecular Medicine. https://doi.org/10.1038/s12276-026-01842-9

Image Credits: AI Generated

DOI: 10.1038/s12276-026-01842-9

Keywords: protein kinase C delta, macrophages, immunometabolism, pyroptosis, atherosclerosis, plaque stability, inflammasome, foam cells, cardiovascular disease, inflammation, Deficiency, protein