Key result
Palmitic acid exposure in macrophages and adipose tissue macrophages from a murine heart failure model upregulates Aquaporin 3 expression and partially inhibits the glycerol 3-phosphate shuttle.
Why the study?
Acute exposure to palmitic acid does not induce a pro-inflammatory phenotype but induces metabolic reprogramming, prompting study into the early stages of this reprogramming in macrophages.
Early exposure to palmitic acid induces metabolic reprogramming in macrophages via aquaporin 3 upregulation to buffer lipids, a mechanism also observed in a murine model of cardiometabolic HFpEF.
Hypothesis-generating for macrophage lipid metabolism in HF; leaves open human translation and clinical relevance.
Macrophages chronically exposed to saturated fatty acids, such as those encountered in adipose tissue, present a pro-inflammatory phenotype with a characteristic foamy morphology. This feature is caused by the excess uptake of circulating lipids, yielding large cytoplasmic lipid bodies formed by triacylglycerols and cholesteryl derivatives. Palmitic acid (PA) is a potent inflammatory inducer in macrophages after chronic exposure to this fatty acid. However, acute exposure to this fatty acid is unable to activate a pro-inflammatory phenotype, although it is sufficient to induce metabolic reprogramming including the formation of small lipid bodies. In the present study, we used an in vitro model of human monocyte-derived macrophages to unravel the early stages of metabolic reprogramming observed in macrophages exposed to PA. We observed that partial inhibition of the glycerol 3-phosphate shuttle is necessary for supplying glycerol 3-phosphate for triacylglycerol biosynthesis. Furthermore, we characterized an alternative pathway to increase the concentration of glycerol 3-phosphate involving an aquaporin and glycerol kinase. Our results suggested that early lipid bodies biogenesis rises as a response mechanism to buffer excessive PA without inducing a pro-inflammatory program. Additionally, we observed that macrophages chronically exposed to PA eventually upregulate the production of inflammatory cytokines. Finally, our in vitro observations were confirmed in adipose tissue macrophages derived from a preclinical mouse model of cardiometabolic heart failure with preserved ejection fraction characterized by heightened adiposity and inflammation. KEY POINTS: The glycerol 3-phosphate shuttle is partially inhibited in palmitic acid-activated macrophages. Aquaporin 3 expression is upregulated in macrophages exposed to palmitic acid and in adipose tissue macrophages from a murine model of cardiometabolic heart failure. Aquaporin 3 participates in the biosynthesis of triacylglycerols by supplying extracellular glycerol.
No takes yet. Share an insight, caveat, or question.
Luévano‐Martínez et al. (2025) studied Cardiometabolic heart failure. Palmitic acid exposure was evaluated on Glycerol 3-phosphate shuttle inhibition and Aquaporin 3 expression. Palmitic acid exposure in macrophages and adipose tissue macrophages from a murine heart failure model upregulates Aquaporin 3 expression and partially inhibits the glycerol 3-phosphate shuttle.
Synapse has enriched 5 closely related papers on similar clinical questions. Consider them for comparative context: