Sulforaphane impedes mitochondrial reprogramming and histone acetylation in polarizing M1 (LPS) macrophages

• Published in: Free radical biology & medicine Vol. 213; pp. 443 - 456
• Main Authors: Bahiraii, Sheyda, Brenner, Martin, Weckwerth, Wolfram, Heiss, Elke H.
• Format: Journal Article
• Language: English
• Published: United States Elsevier Inc 01.03.2024
• Subjects: Fatty acid synthesis; Histone acetylation; Immunometabolism; M1 macrophages; Mitochondria; Sulforaphane; Immunometabolism; Mitochondria; Histone acetylation; M1 macrophages; Sulforaphane; Fatty acid synthesis
• ISSN: 0891-5849; 1873-4596
• DOI: 10.1016/j.freeradbiomed.2024.01.029

M1 (LPS) macrophages are characterized by a high expression of pro-inflammatory mediators, and distinct metabolic features that comprise increased glycolysis, a broken TCA cycle, or impaired OXPHOS with augmented mitochondrial ROS production. This study investigated whether the phytochemical sulforaphane (Sfn) influences mitochondrial reprogramming during M1 polarization, as well as to what extent this can contribute to Sfn-mediated inhibition of M1 marker expression in murine macrophages. The use of extracellular flux-, metabolite-, and immunoblot analyses as well as fluorescent dyes indicative for mitochondrial morphology, membrane potential or superoxide production, demonstrated that M1 (LPS/Sfn) macrophages maintain an unbroken TCA cycle, higher OXPHOS rate, boosted fusion dynamics, lower membrane potential, and less superoxide production in their mitochondria when compared to control M1 (LPS) cells. Sustained OXPHOS and TCA activity but not the concomitantly observed high dependency on fatty acids as fuel appeared necessary for M1 (LPS/Sfn) macrophages to reduce expression of nos2, il1β, il6 and tnfα. M1 (LPS/Sfn) macrophages also displayed lower nucleo/cytosolic acetyl-CoA levels in association with lower global and site-specific histone acetylation at selected pro-inflammatory gene promoters than M1 (LPS), evident in colorimetric coupled enzyme assays, immunoblot and ChIP-qPCR analyses, respectively. Supplementation with acetate or citrate was able to rescue both histone acetylation and mRNA expression of the investigated M1 marker genes in Sfn-treated cells. Overall, Sfn preserves mitochondrial functionality and restricts indispensable nuclear acetyl-CoA for histone acetylation and M1 marker expression in LPS-stimulated macrophages. [Display omitted] •Sfn prevents mitochondrial reprogramming from ATP to ROS production in M1 (LPS) macrophages.•OXPHOS activity supports the anti-inflammatory potential of Sfn.•Increased dependency on fatty acid oxidation alone is insufficient for reduced marker gene expression in M1 (LPS/Sfn) macrophages.•Limited extramitochondrial acetyl-CoA and reduced histone acetylation blunt M1 marker expression in M1 (LPS/Sfn) macrophages.