Dietary PUFAs reduce atherosclerosis and macrophage inflammation, but how nucleotide-binding oligomerization domain leucine-rich repeat-containing receptor protein (NLRP3) inflammasome activation and autophagy influence PUFA-mediated atheroprotection is poorly understood. We fed Ldlr−/− mice diets containing 10% (calories) palm oil (PO) and 0.2% cholesterol, supplemented with an additional 10% of calories as PO, fish oil (FO), echium oil (EO, containing 18:4 n-3), or borage oil (BO, containing 18:3 n-6). Inflammasome activation, autophagic flux, and mitochondrial function were measured in peritoneal macrophages, blood monocytes, or liver from diet-fed mice. Compared with PO, dietary PUFAs (FO, EO, or BO) markedly inhibited inflammasome activation, shown by 1) less macrophage IL-1β secretion and caspase-1 cleavage in response to NLRP3 inflammasome activators, 2) less IL-1β secretion and caspase-1 cleavage from liver or hepatocytes in response to lipopolysaccharide (LPS), and 3) attenuated caspase-1 activity in blood monocytes. Furthermore, PUFA-enriched diets increased LC3-II expression in macrophage, aorta, and liver samples and reduced numbers of dysfunctional mitochondria in macrophages in response to LPS and palmitate, suggesting enhanced autophagic activation. Dietary PUFAs did not attenuate NLRP3 inflammasome activation in atg5-deficient macrophages, indicating that autophagic activation is critical for the PUFA-mediated inflammasome inactivation. In conclusion, dietary PUFAs reduce atherosclerosis, in part, by activation of macrophage autophagy and attenuation of NLRP3 inflammasome activation.

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Background: Mesenchymal stem cells (MSCs) have therapeutic potential for multiple ischemic diseases. However, in vitro expansion of MSCs before clinical application leads to metabolic reprogramming from glycolysis to oxidative phosphorylation, drastically impairing their proliferative and therapeutic capacities. This study aimed to define the regulatory effects of Sirtuin 5 (SIRT5) on the proliferative and therapeutic functions of adipose-derived MSCs (ADMSCs) during in vitro expansion. Methods: ADMSCs were isolated from wild-type (WT) and Sirt5-knockout (Sirt5 −/−) mice. Cell counting assay was used to investigate the proliferative capacities of the ADMSCs. Dihydroethidium and senescence-associated βgalactosidase stainings were used to measure intracellular ROS and senescence levels. Mass spectrometry was used to analyze protein succinylation. Oxygen consumption rates and extra cellular acidification rates were measured as indicators of mitochondrial respiration and glycolysis. Metabolic-related genes expression were verified by quantitative PCR and western blot. Hind limb ischemia mouse model was used to evaluate the therapeutic potentials of WT and Sirt5 −/− ADSMCs. Results: SIRT5 protein levels were upregulated in ADMCs during in vitro expansion. Sirt5 −/− ADMSCs exhibited a higher proliferation rate, delayed senescence, and reduced ROS accumulation. Furthermore, elevated protein succinylation levels were observed in Sirt5 −/− ADMSCs, leading to the reduced activity of This is an open access article under the terms of the Creative Commons Attribution License, which permits use, distribution and reproduction in any medium, provided the original work is properly cited.

Background and aims: Dietary long-chain (≥ 20 carbons) n-3 polyunsaturated fatty acids (PUFAs) reduce atherosclerosis and enhance macrophage autophagy activation. How macrophage autophagy impacts atherosclerotic progression, particularly when comparing dietary n-3 PUFA supplementation vs. saturated fat feeding, is unknown. Methods:We generated myeloid-specific autophagy-deficient and control mice in the Ldlr −/− background by transplanting bone marrow from myeloid-specific autophagy-related (atg) 5 knockout mice and wild type controls into irradiated Ldlr −/− recipients. After 7 weeks for recovery from radiation, mice were fed an atherogenic diet containing 0.2% cholesterol and 20% calories as palm oil (PO diet), or 10% calories as PO plus 10% calories as fish oil (FO diet) for 16 weeks.Results: Compared to PO, FO significantly reduced plasma cholesterol, triglyceride, hepatic neutral lipid, and aortic caspase-1 cleavage, but increased aortic efferocytosis, leading to attenuated atherosclerosis in Ldlr −/− mice receiving wild type bone marrow. Myeloid atg5 deletion had little impact on plasma lipid concentrations and hepatic neutral lipid content, regardless of diet. Myeloid atg5 deletion increased aortic caspase-1 cleavage, decreased aortic efferocytosis and worsened atherosclerosis only in the FO-fed Ldlr −/− mice.