Erlich Jonathan R, To Eunice E, Luong Raymond, Liong Felicia, Liong Stella, Oseghale Osezua, Miles Mark A, Bozinovski Steven, Brooks Robert D, Vlahos Ross, Chan Stanley, O'Leary John J, Brooks Doug A, Selemidis Stavros
School of Health and Biomedical Sciences, RMIT University, Bundoora 3083, Australia.
F.M. Kirby Neurobiology Centre, Boston Children's Hospital, Harvard Medical School, Boston, MA 02115, USA.
Antioxidants (Basel). 2022 Jul 29;11(8):1488. doi: 10.3390/antiox11081488.
Macrophages undergo a metabolic switch from oxidative phosphorylation to glycolysis when exposed to gram-negative bacterial lipopolysaccharide (LPS), which modulates antibacterial host defence mechanisms. Here, we show that LPS treatment of macrophages increased the classical oxidative burst response via the NADPH oxidase (NOX) 2 enzyme, which was blocked by 2-deoxyglucose (2-DG) inhibition of glycolysis. The inhibition of the pentose phosphate pathway with 6-aminonicotinamide (6-AN) also suppressed the LPS-induced increase in NOX2 activity and was associated with a significant reduction in the mRNA expression of NOX2 and its organizer protein p47phox. Notably, the LPS-dependent enhancement in NOX2 oxidase activity was independent of both succinate and mitochondrial reactive oxygen species (ROS) production. LPS also increased type I IFN-β expression, which was suppressed by 2-DG and 6-AN and, therefore, is dependent on glycolysis and the pentose phosphate pathway. The type I IFN-β response to LPS was also inhibited by apocynin pre-treatment, suggesting that NOX2-derived ROS promotes the TLR4-induced response to LPS. Moreover, recombinant IFN-β increased NOX2 oxidase-dependent ROS production, as well as NOX2 and p47phox expression. Our findings identify a previously undescribed molecular mechanism where both glycolysis and the pentose phosphate pathway are required to promote LPS-induced inflammation in macrophages.
巨噬细胞在暴露于革兰氏阴性菌脂多糖（LPS）时会经历从氧化磷酸化到糖酵解的代谢转换，这一过程调节抗菌宿主防御机制。在此，我们表明，用LPS处理巨噬细胞会通过NADPH氧化酶（NOX）2增加经典的氧化爆发反应，而这种反应会被2-脱氧葡萄糖（2-DG）抑制糖酵解所阻断。用6-氨基烟酰胺（6-AN）抑制磷酸戊糖途径也会抑制LPS诱导的NOX2活性增加，并与NOX2及其组织蛋白p47phox的mRNA表达显著降低有关。值得注意的是，LPS依赖的NOX2氧化酶活性增强与琥珀酸和线粒体活性氧（ROS）的产生均无关。LPS还会增加I型干扰素-β（IFN-β）的表达，这一表达会被2-DG和6-AN所抑制，因此依赖于糖酵解和磷酸戊糖途径。对LPS的I型IFN-β反应也会被阿朴吗啡预处理所抑制，这表明NOX2衍生的ROS促进了TLR4诱导的对LPS的反应。此外，重组IFN-β会增加NOX2氧化酶依赖的ROS产生，以及NOX2和p47phox的表达。我们的研究结果确定了一种以前未被描述的分子机制，即糖酵解和磷酸戊糖途径都需要促进巨噬细胞中LPS诱导的炎症反应。
