Chronic anatabine administration attenuates cardiovascular activity by targeting NF-κB/caspase-1/NLRP3-dependent pyroptosis and oxidative stress in paraventricular nucleus of hypertensive rat

Objectives : The hypertensive process is a chronic low-grade inflammation. Anatabine, a natural alkaloid with anti-inflammatory properties, can modulate inflammatory pathways. Therefore, this study sought to explore the impact of anatabine on cardiovascular activity in hypertensive rats, focusing on mechanisms associated with inflammation and oxidative stress. Method : We collected fecal samples from male spontaneously hypertensive rats (SHR) and Wistar-Kyoto (WKY) rats (300-350g), and performed untargeted metabolomics analysis. Anatabine was identified as the potential metabolite, and anatabine dicitrate (20 mg/kg) within mini-pump was subcutaneously implanted in SHR or WKY for 12- week. Systolic pressure was recorded weekly and cardiovascular events were detected at terminated animal study. Angiotensin II induced microglia (HMC3) was treated with anatabine and PapRIV (NF-κB activator) to explore the molecular mechanism. Results : High blood pressure significantly triggered nucleotide-binding domain, leucine-rich-containing family pyrin domain containing 3 (NLRP3)-dependent inflammasome assembly (ASC, Caspase-1, and NLRP3) and pyroptosis (GSDMD) in the hypothalamic paraventricular nucleus (PVN), which evoked massive inflammatory cytokine production (IL-1β, TNF-α, IL-10, IL-18, and MCP-1) and oxidative stress responses (Cu/Zn-SOD activity, GSH-PX, and MDA) in the SHR group. Notably, anatabine not only improved cardiac function and attenuated sympathetic activation, but also reduced the intensity of inflammatory reaction from the NLRP3-dependent inflammasome and pyroptosis, and decreased reactive oxygen species (ROS) overproduction in the PVN of hypertensive rats. Furthermore, microglia stimulated inflammation after adding Ang II; oxidative stress responses were activated, while the inflammasome compounds and cytokines were overexpressed. The anatabine inhibited NLRP3-mediated pyroptosis and oxidative stress in Ang II-induced microglia. However, those responses were aggravating after the NF-κB activator. Conclusion : Chronic hypertension activated the NLRP3 inflammasome and pyroptosis-driven inflammatory responses, triggering oxidative stress in the PVN. Anatabine, a natural alkaloid with anti-inflammatory properties, has shown potential capability for inhibition of inflammation. Sustained adminstration anatabine cross the blood-brain barrier arriving the PVN and effectively lowed blood pressure, reduced sympathetic drive, and improved cardiac function, by suppressing the NF-κB/caspase- 1/NLRP3-dependent pyroptosis pathway in microglia, curbing excessive ROS generation in paraventricular nucleus of hypertensive rat