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Berberine Suppresses SASP in Atherosclerosis via RXRα/PPARγ/
2026-06-05
Berberine Modulates SASP-Driven Inflammation Through RXRα/PPARγ/NEDD4 in Atherosclerosis
Study Background and Research Question
Atherosclerosis is a progressive vascular disease characterized by lipid accumulation, chronic inflammation, and the formation of atherosclerotic plaques. Recent advances in single-cell sequencing have revealed an abundance of senescent macrophage-derived foam cells within human carotid plaques, which contribute to persistent inflammation through the senescence-associated secretory phenotype (SASP). SASP denotes a pro-inflammatory state in aging cells, marked by elevated secretion of cytokines, chemokines, and matrix-remodeling proteins, thus perpetuating local tissue damage and systemic risk.While berberine (BBR), a natural isoquinoline alkaloid, has been previously noted for anti-senescent effects, the precise molecular mechanisms by which it modulates SASP and impacts atherosclerotic progression remained unclear. The central research question addressed by the reference study (Berberine Targets RXRα/PPARγ/NEDD4 to Suppress SASP in Atherosclerosis) was to elucidate the signaling pathways through which berberine exerts anti-inflammatory effects on macrophage-derived foam cells in atherosclerotic lesions.
Key Innovation from the Reference Study
A key advance of the study lies in the identification of the RXRα/PPARγ/NEDD4 axis as a pivotal regulatory pathway mediating the anti-SASP and anti-inflammatory effects of berberine in atherosclerosis. The research demonstrates that berberine treatment not only activates PPARγ via RXRα-dependent mechanisms in macrophages, but also upregulates NEDD4 transcription, promoting ubiquitination-dependent degradation of the GATA4/p62 complex. This results in effective suppression of SASP-associated inflammatory protein production, providing a mechanistic basis for berberine’s protective action in vascular aging (see also internal summary).Methods and Experimental Design Insights
The authors employed a multi-level experimental strategy:- In vivo modeling: ApoE−/− mice fed a high-fat diet to induce atherosclerosis, with or without berberine treatment.
- Plaque and blood assessment: Morphological analysis of aortic plaques and measurement of blood lipid and inflammatory markers post-treatment.
- Single-cell transcriptomics: Smart-seq analysis of human carotid plaques to profile cell populations and inflammatory states.
- In vitro cellular assays: RAW264.7 macrophages and peritoneal macrophage-derived foam cells were used to dissect berberine's effects on SASP-related proteins, GATA4/p62 complex stability, and ubiquitination dynamics.
- Pathway interrogation: Lentiviral knockdown of RXRα in plaque macrophages was performed to test the necessity of RXRα in berberine’s protective effect.
Core Findings and Why They Matter
The central findings demonstrate that berberine significantly reduces SASP-driven inflammation in atherosclerotic plaques by activating the RXRα/PPARγ/NEDD4 pathway. Mechanistically, berberine increases the transcriptional activity of RXRα and PPARγ in foam cells, boosting NEDD4 expression. This in turn promotes the ubiquitination and degradation of the GATA4/p62 complex, a critical factor for SASP protein production. The anti-inflammatory effect is abolished if RXRα is knocked down in macrophages, underscoring the pathway’s functional necessity (internal reference).These results extend the understanding of how PPARγ signaling pathway inhibitors, or modulators of the PPARγ/RXRα heterodimer, can be leveraged to dissect the cellular mechanisms underlying vascular aging and chronic inflammation. Notably, the study aligns with the broader paradigm of targeting nuclear receptor signaling complexes to control age-associated pathologies.
Comparison with Existing Internal Articles
This mechanistic insight resonates with prior internal analyses. For example, the article "T0070907: Precision PPARγ Antagonist for Pathway Dissection" describes how selective PPARγ antagonists enable precise dissection of adipogenesis, inflammation, and cell cycle dynamics in cellular models. Similarly, "T0070907: Unraveling PPARγ Antagonism for Cell Fate and Inflammation" emphasizes the value of targeted PPARγ modulation for exploring cell fate decisions and inflammatory signaling. The present berberine study adds a complementary perspective by linking upstream RXRα activation and downstream NEDD4-mediated protein turnover to SASP suppression, supporting a multi-nodal experimental design for PPARγ signaling research.Limitations and Transferability
While the findings robustly demonstrate berberine’s suppression of SASP via the RXRα/PPARγ/NEDD4 pathway in mouse and cell culture models, several limitations merit consideration:- Species and model specificity: The study relies on murine models and murine-derived macrophages; transferability to human vascular disease requires further validation.
- Pathway specificity: Although RXRα/PPARγ/NEDD4 was shown to be essential in this context, the broader landscape of SASP regulation likely involves additional pathways yet to be mapped.
- Pharmacokinetics: The in vivo dosing and bioavailability of berberine in human tissues may differ from experimental conditions.
Protocol Parameters
- Berberine administration: In ApoE−/− mice, berberine was administered after establishment of a high-fat diet-induced atherosclerotic phenotype; dosing and duration were optimized for plaque and inflammatory marker readouts.
- Macrophage-derived foam cell assays: RAW264.7 cells and peritoneal macrophages were differentiated into foam cells using ox-LDL prior to berberine or pathway modulator treatment.
- Lentiviral knockdown: Macrophage-specific RXRα knockdown was achieved with pLVCD68-shRNA lentivirus, administered directly into atherosclerotic plaques.
- Pathway readouts: Assessment included quantification of SASP-related proteins, GATA4/p62 complex stability, ubiquitination status, and inflammatory cytokine secretion.