Tongxinluo attenuates pulmonary microvascular endothelial cell senescence in COPD by targeting the GADD45B-MAPK axis

Growing evidence implicates the accelerated cellular aging in the lung is a pivotal contributor in the pathogenesis of Chronic Obstructive Pulmonary Disease (COPD). Notably, the specific role of senescent pulmonary microvascular endothelial cells (PMECs) and the development of therapies targeting them remain poorly defined. Tongxinluo (TXL), a patent traditional Chinese medicine with "Yiqi Huoxue Tongluo" effects, shows therapeutic promise in COPD, potentially by mitigating PMEC injury. However, the precise molecular mechanisms and key bioactive constituents underlying TXL's action are incompletely elucidated.

To explore the contribution of PMEC senescence to COPD pathogenesis and elucidate whether and how TXL attenuates COPD progression through modulating PMEC senescence.

COPD models were induced in both C57BL/6J and ERCC1^± mice via cigarette smoke (CS) exposure. TXL was administrated daily via intragastric gavage. The progression of cellular senescence and COPD was dynamically monitored by RT-qPCR, immunofluorescence staining, H&E staining and lung function test. In vitro human PMECs (HPMECs) injury model was induced by cigarette smoke extract (CSE) exposure. Bulk RNA-seq, LC-MS/MS, network pharmacology, and in vitro cellular assay were integrated to explore TXL's key targets and bioactive components in mitigating PMEC senescence and subsequent COPD progression.

In both C57BL/6J and ERCC1^± COPD mice, we demonstrated that CS exposure triggered PMEC senescence, evidenced by upregulated senescence markers (P21, P16, P53, γ-H2AX) and SASPs (IL-6, IL-1β, TNF-α), correlating with alveolar destruction and lung function decline. ERCC1^± mice exhibited exacerbated senescence and COPD progression, underscoring the role of DNA damage in aging-related pathology. TXL treatment attenuated these effects, reducing senescence markers, improving lung morphology, and restoring function. In vitro, TXL and its active component, effectively reversed CSE-induced cellular senescence in human PMECs (HPMECs). Mechanistically, an integrative approach combining RNA-sequencing analysis, LC-MS/MS analysis for TXL's comprehensive ingredients, network pharmacology, and confirmatory experiments demonstrated that TXL and its potential constituent ginsenoside Rg1, attenuated CSE-induced PMEC senescence through regulation of GADD45B-MAPK signaling pathway, offering a novel therapeutic strategy for COPD.

This investigation demonstrates that the temporal aggravation of PMEC senescence serves as a pivotal factor in the advancement of COPD. TXL and its potential constituent, ginsenoside Rg1, markedly suppressed COPD progression by modulating of the GADD45B-MAPK signaling cascade in PMECs. These findings not only contribute novel perspectives to the understanding of COPD etiology but also emphasize the therapeutic promise of TXL and its core component, ginsenoside Rg1, as an intervention targeting senescence modulation in the management of COPD.