Chronic Anatabine Administration Attenuates Cardiovascular Activity by Targeting NF-κB/NLRP3/Caspase-1-Dependent Pyroptosis and Oxidative Stress in Paraventricular Nucleus of Hypertensive Rat.

Hypertension is characterized by chronic inflammation. Anatabine, a natural alkaloid with anti-inflammatory properties, has demonstrated potential in regulating inflammatory pathways. However, its impact on cardiovascular activity in the context of hypertension remains unclear. The aim of this study was to explore the effects of anatabine on cardiovascular activity in hypertensive rats, with a specific focus on the underlying mechanisms related to inflammation and oxidative stress, particularly the role of NLRP3 inflammasome and pyroptosis in the PVN. Fecal samples were collected from male spontaneously hypertensive rats (SHR) and Wistar Kyoto (WKY) rats, followed by untargeted metabolomics analysis by liquid chromatography-mass spectrometry (LC-MS). Anatabine (ANT) was identified as enriched in WKY while lacking in SHR and thus was subcutaneously administered via mini-pump (0.014 mg/kg/min) in SHR or WKY rats for 12 weeks. Systolic blood pressure was recorded weekly. In vitro, microglia (HMC3) were divided into control, angiotensin II (Ang II), Ang II + anatabine, and Ang II + anatabine + PapRIV (Pap, NF-κB activator) groups. High blood pressure significantly triggered nucleotide-binding domain, leucine-rich-containing family pyrin domain containing 3 (NLRP3)-dependent inflammasome activation (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-18, and MCP-1) and oxidative stress responses (Cu/Zn-SOD activity, GSH-PX, and MDA) in the SHR group. Notably, anatabine not only prevented cardiac structural remodeling and attenuated sympathetic activation but also reduced the inflammatory reaction from the NF-κB activity, NLRP3-dependent inflammasome and pyroptosis, and decreased reactive oxygen species (ROS) overproduction in the PVN of hypertensive rats. In vitro, microglia stimulated inflammation after adding Ang II; oxidative stress responses were activated, while the inflammasome compounds and cytokines were overexpressed. The anatabine inhibited NF-κB activity, NLRP3/caspase-1-dependent pyroptosis and oxidative stress in Ang II-induced microglia. Conversely, those responses were aggravated after the NF-κB activator in HMC3. Chronic hypertension activates the NLRP3 inflammasome and pyroptosis-driven inflammatory responses, leading to oxidative stress in the PVN. Sustained administration of anatabine reached the PVN and suppressed the NF-κB/NLRP3/caspase-1-dependent pyroptosis pathway in microglia, reducing excessive ROS generation in the PVN, thereby effectively reducing sympathetic drive, attenuating blood pressure, and preventing cardiac structural remodeling in the process of hypertension. These findings suggest anatabine as a promising therapeutic agent for managing hypertension-related chronic inflammation.