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Inhibiting the CaN/FoxO1/FABP4 Axis Prevents SERCA2-Induced
2026-05-13
Targeting the CaN/FoxO1/FABP4 Pathway in SERCA2 Dysfunction-Driven Atherosclerosis
Study Background and Research Question
Atherosclerosis is recognized as a chronic inflammatory disease, characterized by the accumulation of lipid-rich plaques within arterial walls, underpinning major cardiovascular events such as myocardial infarction and stroke. A crucial aspect of its pathogenesis is the transformation of macrophages into lipid-laden foam cells, driven by disrupted lipid metabolism and persistent inflammation. The sarcoplasmic/endoplasmic reticulum Ca2+ ATPase 2 (SERCA2) enzyme maintains cellular calcium homeostasis; mutations that impair its function are associated with increased endoplasmic reticulum (ER) stress, inflammation, and atherosclerotic lesion formation. However, the downstream molecular pathways linking SERCA2 dysfunction to foam cell formation and plaque progression remained unclear. The present study (Tong et al., 2025) aimed to elucidate whether SERCA2 dysfunction promotes atherosclerosis by disrupting fatty acid metabolism in macrophages and to identify therapeutic targets within this signaling cascade.Key Innovation from the Reference Study
The central innovation of Tong et al. lies in identifying and functionally validating the calcineurin (CaN)/forkhead box O1 (FoxO1)/fatty acid binding protein 4 (FABP4) axis as a mechanistic link between SERCA2 dysfunction and atherosclerotic progression. By employing a genetic mouse model with a heterozygous C674S mutation in SERCA2 (SKI mice), the authors demonstrate that SERCA2 impairment leads to upregulation of calcineurin in bone marrow-derived macrophages (BMDMs). This, in turn, drives nuclear translocation of FoxO1 and subsequent transcriptional upregulation of FABP4 — a protein centrally involved in fatty acid uptake and foam cell formation. Importantly, pharmacological inhibition of FABP4, either via small molecules such as BMS 309403 or genetic deficiency, successfully interrupts this pathway, normalizing lipid metabolism and reducing atherosclerotic lesion formation (Tong et al., 2025).Methods and Experimental Design Insights
To dissect the pathway, the study utilized:- Genetic mouse models: Heterozygous SERCA2 C674S knock-in (SKI) mice to model SERCA2 dysfunction under physiological and pathological conditions.
- Metabolomics: Comparative serum metabolomics between SKI and wild-type mice to identify systemic metabolic shifts.
- Histological analysis: Quantification of atherosclerotic plaques in aorta and aortic root through established staining and imaging protocols.
- In vitro macrophage assays: BMDMs from SKI and control mice assessed for protein expression (immunoblotting), lipid uptake/accumulation (fluorescent labeling and microscopy), and foam cell formation.
- Pharmacological interventions: Application of selective FoxO1 inhibitors and the potent FABP4 inhibitor BMS 309403 to probe pathway dependency and therapeutic potential.
Protocol Parameters
- cell-based foam cell assay | 1–25 μM BMS 309403 | BMDMs, THP-1 macrophages | Literature reports this range allows effective FABP4 inhibition without cytotoxicity | product_spec
- in vivo chronic administration | 10–30 mg/kg/day BMS 309403 | murine atherosclerosis models | Dose range leads to significant reduction in lesion area and improved metabolic parameters | workflow_recommendation
- stock preparation | 18.15 mg/mL in DMSO | in vitro use | Ensures adequate solubility and stability for cell-based assays | product_spec
- solution storage | −20°C for several months | all formats | Maintains compound integrity for reproducible results | product_spec
Core Findings and Why They Matter
The study provides several pivotal findings:- SERCA2 dysfunction in macrophages upregulates calcineurin, which increases nuclear FoxO1 activity and FABP4 expression (Tong et al., 2025).
- This pathway promotes excessive fatty acid uptake and foam cell formation, accelerating atherosclerotic plaque development.
- Inhibition of either FoxO1 or FABP4 — genetically or pharmacologically — disrupts this axis, reduces lipid accumulation, and significantly ameliorates atherosclerosis in SKI mice (Tong et al., 2025).
- BMS 309403, a highly selective FABP4 inhibitor, effectively blocks foam cell formation in both in vitro macrophage assays and in vivo models, supporting its utility for mechanistic and translational research (Tong et al., 2025).
Comparison with Existing Internal Articles
The new evidence from Tong et al. is well aligned with recent translational and methodological reviews. For instance, "BMS 309403 and FABP4: Translational Strategies in Atherosclerosis" elaborates on how the inhibition of FABP4 disrupts macrophage lipid handling, and integrates CaN/FoxO1/FABP4 axis data to provide protocol guidance. Additionally, "BMS 309403: Selective FABP4 Inhibitor for Atherosclerosis Research" and "Applied Protocols for FABP4 Inhibition in Atherosclerosis" detail the utility and technical boundaries of BMS 309403, including its nanomolar affinity (Ki < 2 nM) and DMSO solubility, in both cell-based and in vivo systems (source: product_spec). The present study further substantiates these applications by demonstrating the mechanistic necessity of FABP4 in SERCA2-driven atherogenic signaling.Limitations and Transferability
While the study robustly links SERCA2 dysfunction to atherosclerosis via the CaN/FoxO1/FABP4 pathway in murine models and primary BMDMs, several translational caveats remain:- The SKI mouse model, though physiologically relevant, may not capture all aspects of human SERCA2 mutations or cardiovascular pathology.
- Pharmacological interventions were performed in controlled laboratory settings; further validation in diverse genetic backgrounds and comorbid states is necessary.
- Long-term systemic inhibition of FABP4 could impact other metabolic organs; off-target and compensatory effects require evaluation in future studies.