Effects of Rehmannia glutinosa Libosch. Rhizome water extract and Rehmapicrogenin on pulmonary hypertension: Multi-omics insights into epidermal growth factor receptor/pyruvate kinase M2 pathway and metabolic regulation.

Abstract

ETHNOPHARMACOLOGICAL RELEVANCE: Rehmannia glutinosa Libosch. (RG), as one of the 'Four Famous Chinese Medicinal Herbs', has a long history of medicinal use and is classified as belonging to the meridians of the heart, liver, and kidney. RG has the effects of clearing heat and cooling blood, nourishing yin, and generating fluids. Pulmonary hypertension (PH) is a cardiovascular disease, and its pathogenesis can be summarized as 'yin deficiency', 'blood stasis', and 'qi deficiency'. The efficacy of RG is highly compatible with this disease, and the compounds isolated from RG can significantly inhibit the proliferation of pulmonary arterial smooth muscle cells (PASMCs). However, the mechanism by which it intervenes in PH remains unclear. OBJECTIVE: In this study, the mechanisms and active components of RG were investigated for treating PH by using multi-omics analysis and surface plasmon resonance (SPR) technology, providing experimental support for clinical application. METHODS: A PH mouse model was established through 5 weeks of hypoxia, with RG administration starting in week four. Cardiorespiratory function was evaluated after treatment. The therapeutic targets of RG were identified via 16S rDNA sequencing, metagenomics, and metabolomics. SPR ligand fishing was performed to isolate rehmapicrogenin (Reh), an RG-derived compound that targets the epidermal growth factor receptor (EGFR). The effects and mechanisms of Reh were assessed by measuring cardiac and pulmonary function, oxidative stress, apoptosis, immune cell activity, and glycolysis. An in vitro model of hypoxia-induced PASMCs proliferation was used to validate Reh's mechanism with an EGFR agonist (NSC). RESULTS: RG extracts improved cardiorespiratory function and regulated gut microbiota, correcting the Firmicutes/Bacteroidetes (F/B) ratio in PH mice. RG also mitigated metabolic disturbances and inhibited glycolysis through pyruvate kinase M2 (PKM2) regulation, as confirmed using immunofluorescence analysis, western blotting, and PCR. SPR identified Reh as the active ingredient, which improved cardiorespiratory function, reduced oxidative stress and apoptosis, and suppressed EGFR and PKM2 expression and glycolysis. In vitro, Reh inhibited PASMC migration and proliferation, alleviated oxidative stress, and reduced mitochondrial damage. These effects were reversed upon NSC addition, confirming the role of EGFR in the mechanism. CONCLUSION: RG and its active compound Reh mitigate hypoxia-induced PH by targeting the EGFR/PKM2 pathway, reducing glycolysis, and regulating gut microbiota dysbiosis.