TREM-1 Governs NLRP3 Inflammasome Activation of Macrophages by Firing Up Glycolysis in Acute Lung Injury

The triggering receptor expressed on myeloid cells-1 (TREM-1) is a pro-inflammatory immune receptor potentiating acute lung injury (ALI). However, the mechanism of TREM-1-triggered inflammation response remains poorly understood. Here, we showed that TREM-1 blocking attenuated NOD-, LRR- and pyrin domain-containing 3 (NLRP3) inflammasome activation and glycolysis in LPS-induced ALI mice. Then, we observed that TREM-1 activation enhanced glucose consumption, induced glycolysis, and inhibited oxidative phosphorylation in macrophages. Specifically, inhibition of glycolysis with 2-deoxyglucose diminished NLRP3 inflammasome activation of macrophages triggered by TREM-1. Hypoxia-inducible factor-1α (HIF-1α) is a critical transcriptional regulator of glycolysis. We further found that TREM-1 activation facilitated HIF-1α accumulation and translocation to the nucleus the phosphoinositide 3-kinase (PI3K)/AKT/mammalian target of rapamycin (mTOR) pathway. Inhibiting mTOR or HIF-1α also suppressed TREM-1-induced metabolic reprogramming and NLRP3/caspase-1 activation. Overall, the mTOR/HIF-1α/glycolysis pathway is a novel mechanism underlying TREM-1-governed NLRP3 inflammasome activation. Therapeutic targeting of the mTOR/HIF-1α/glycolysis pathway in TREM-1-activated macrophages could be beneficial for treating or preventing inflammatory diseases, such as ALI.