Fufang Zhenzhu Tiaozhi (FTZ) suppression of macrophage pyroptosis: Key to stabilizing rupture-prone plaques.

BACKGROUND: Research on the Chinese herbal formula Fufang Zhenzhu Tiaozhi (FTZ) has demonstrated its effectiveness in treating hyperlipidemia and glycolipid metabolic disorders. Additionally, FTZ has shown inhibitory effects on oxidative stress, regulation of lipid metabolism, and reduction of inflammation in these conditions. However, the precise mechanisms through which FTZ modulates macrophage function in atherosclerosis remain incompletely understood. Therefore, this study aims to investigate whether FTZ can effectively stabilize rupture-prone plaques by suppressing macrophage pyroptosis and impeding the development of M1 macrophage polarization in ApoE-/- mice. METHODS: To assess the impact of FTZ on macrophage function and atherosclerosis in ApoE-/- mice, we orally administered FTZ at a dosage of 1.2 g/kg body weight daily for 14 weeks. Levels of interleukin-18 and interleukin-1ß were quantified using ELISA kits to gauge FTZ's influence on inflammation. Total cholesterol content was measured with a Cholesterol Assay Kit to evaluate FTZ's effect on lipid metabolism. Aortic tissues were stained with Oil Red O, and immunohistochemistry techniques were applied to assess atherosclerotic lesions and plaque stability. To evaluate the effects of FTZ on macrophage pyroptosis and oxidative damage, immunofluorescence staining was utilized. Additionally, we conducted an analysis of protein and mRNA expression levels of NLRP3 inflammasome-related genes and macrophage polarization-related genes using RT-PCR and western blotting techniques. RESULTS: This study illustrates the potential therapeutic effectiveness of FTZ in mitigating the severity of atherosclerosis and improving serum lipid profiles by inhibiting inflammation. The observed enhancements in atherosclerosis severity and inflammation can be attributed to the suppression of NLRP3 inflammasome activity and M1 polarization by FTZ. CONCLUSION: The current findings indicate that FTZ provides protection against atherosclerosis, positioning it as a promising candidate for novel therapies targeting atherosclerosis and related cardiovascular diseases.

Mitochondrial damage and activation of the cytosolic DNA sensor cGAS-STING pathway lead to cardiac pyroptosis and hypertrophy in diabetic cardiomyopathy mice.

Diabetic cardiomyopathy (DCM) is a serious cardiac complication of diabetes that currently lacks specific treatment. The cyclic GMP-AMP synthase (cGAS)-stimulator of interferon genes (STING) signaling pathway has been suggested to contribute to the pathogenesis of cardiovascular diseases. However, whether cGAS-STING is involved in the development of DCM has not been established. Our study aimed to determine the role of cGAS-STING in the initiation of nucleotide-binding oligomerization domain-like receptor pyrin domain containing 3 (NLRP3) inflammasome-induced cardiac pyroptosis and chronic inflammation during the pathogenesis of DCM. C57BL/6J mice were preinjected with adeno-associated virus 9 (AAV9) intravenously via the tail vein to specifically knock down myocardial STING. After four weeks, mice with myocardium-specific knockdown of STING received injections of streptozotocin (STZ; 50 mg/kg) and a high-fat diet to induce diabetes. Measurements included echocardiography, immunohistochemical analyses, wheat germ agglutinin (WGA) staining, and western blotting. Here, we showed that the cGAS-STING signaling pathway was activated in diabetic hearts, which was indicated by the increased phosphorylation of TANK-binding kinase 1 (TBK1) and interferon (IFN) regulatory factor 3 (IRF3), leading to the activation of the NLRP3 inflammasome in the hearts of diabetic mice and proinflammatory cytokine release into serum. Moreover, STING knockdown via adeno-associated virus-9 (AAV9) in diabetic mouse heart alleviated cardiac pyroptosis and the inflammatory response, prevented diabetes-induced hypertrophy, and restored cardiac function. Mechanistically, we showed that palmitic acid (PA)-induced lipotoxicity impairs mitochondrial homeostasis, producing excessive mitochondrial reactive oxygen species (mtROS), which results in oxidative damage to mitochondrial DNA (mtDNA) and its release into the cytoplasm while switching on cGAS-STING-mediated pyroptosis in cardiomyocytes, thereby worsening the progression of diabetic cardiomyopathy. Our study demonstrated that activation of the cGAS-STING pathway caused by mitochondrial oxidative damage and mtDNA escape induced by free fatty acids promoted pyroptosis and proinflammatory responses in cardiomyocytes in a NLRP3 inflammasome-dependent manner, thus promoting myocardial hypertrophy during the progression of DCM.

The Chinese herbal medicine Fufang Zhenzhu Tiaozhi protects against diabetic cardiomyopathy by alleviating cardiac lipotoxicity-induced oxidative stress and NLRP3-dependent inflammasome activation.

BACKGROUND: Fufang Zhenzhu Tiao Zhi (FTZ) formula is a Chinese herbal preparation used in the clinical treatment of disorders of glucolipid metabolism. Given its effective actions on the regulation of lipid dysfunction and its anti-inflammatory and antioxidative effects, we designed this study to investigate the cardioprotective effect and possible mechanism of FTZ in diabetic cardiomyopathy (DCM) mice. METHODS: FTZ was administered to diabetic mice by oral gavage daily at a dose of 1.2 g/kg or 2.4 g/kg bodyweight for 8 weeks. Doppler echocardiography, H&E, and WGA staining were used to evaluate cardiac function and structure in the mice. The levels of proinflammatory cytokines and lipids in serum were detected with corresponding commercial kits. Immunofluorescence staining and flow cytometry were used to detect oxidation damage and pyroptosis in myocardial cells. RT-PCR and western blotting were used to analyze the protein and mRNA expression levels of NLRP3 inflammasome-related genes. RESULTS: Our study indicated that FTZ improved cardiac function, attenuated heart hypertrophy, improved serum lipid and proinflammatory cytokine levels, and restrained oxidative stress and NLRP3 inflammasome-induced inflammatory activities in diabetic mouse hearts. The in vitro data suggested that FTZ suppressed intercellular lipid accumulation as well as palmitic acid (PA)-induced oxidative stress and NLRP3 inflammasome-dependent pyroptosis in cardiomyocytes. CONCLUSION: Our present findings indicate that FTZ inhibits DCM by inhibiting both oxidative stress and NLRP3 inflammasome activation induced by cardiac lipotoxicity.