Qian Yang Yu Yin Granule prevents hypertensive cardiac remodeling by inhibiting NLRP3 inflammasome activation via Nrf2

Ethnopharmacological relevance

Qian Yang Yu Yin Granule (QYYYG), a traditional Chinese poly-herbal formulation, has been validated in clinical trials to mitigate cardiac remodeling (CR), and cardiac damage in patients with hypertension. However, the specific mechanism remains unclear.

Aim of the study

This study explored the potential effects and potential mechanisms of QYYYG on hypertensive CR by combining various experimental approaches.

Materials and methods

Spontaneously hypertensive rats (SHRs) were used as a model of hypertensive CR, followed by QYYYG interventions. Blood pressure, cardiac function and structure, histopathological changes, and myocardial inflammation and oxidative stress were tested to assess the efficacy of QYYYG in SHRs. For in vitro experiments, a cell model of myocardial hypertrophy and injury was constructed with isoprenaline. Cardiomyocyte hypertrophy, oxidative stress, and death were examined after treatment with different concentrations of QYYYG, and transcriptomics analyses were performed to explore the underlying mechanism. Nrf2 and the ROS/NF-κB/NLRP3 inflammasome pathway were detected. Thereafter, ML385 and siRNAs were used to inhibit Nrf2 in cardiomyocytes, so as to verify whether QYYYG negatively regulates the NLRP3 inflammasome by targeting Nrf2, thereby ameliorating the associated phenotypes. Finally, high performance liquid chromatography (HPLC) was conducted to analyze the active ingredients in QYYYG, and molecular docking was utilized to preliminarily screen the compounds with modulatory effects on Nrf2 activities.

Results

QYYYG improved blood pressure, cardiac function, and structural remodeling and attenuated myocardial inflammation, oxidative stress, and cell death in SHRs. The transcriptomics results showed that the inflammatory response might be crucial in pathological CR and that Nrf2, which potentially negatively regulates the process, was upregulated by QYYYG treatment. Furthermore, QYYYG indeed facilitated Nrf2 activation and negatively regulated the ROS/NF-κB/NLRP3 inflammasome pathway, therefore ameliorating the associated phenotypes. In vitro inhibition or knockdown of Nrf2 weakened or even reversed the repressive effect of QYYYG on ISO-induced inflammation, oxidative stress, pyroptosis, and the NLRP3 inflammasome activation. Based on the results of HPLC and molecular docking, 30 compounds, including cafestol, genistein, hesperetin, and formononetin, have binding sites to Keap1–Nrf2 protein and might affect the activity or stability of Nrf2.

Conclusion

In conclusion, the alleviatory effect of QYYYG on hypertensive CR is related to its regulation of Nrf2 activation. Specifically, QYYYG blocks the activation of the NLRP3 inflammasome by boosting Nrf2 signaling and depressing myocardial inflammation, oxidative stress, and pyroptosis, thereby effectively ameliorating hypertensive CR.