SMRT controlled inflammation in cDC1 is orchestrated through mTOR-Succinate axis despite of suppressed glycolysis

Immunogenic activation of DCs by TLRs involves coordinated metabolic and transcriptional rewiring. The negative regulation of such metabolic rearrangements in DCs remains elusive. We have recently reported that Ncor2 (SMRT) loss of function renders cDC1 DCs to be highly inflammatory in nature by polarizing the naïve CD4+T cells towards the Th1 phenotype. Here, we sought to establish an immunometabolic relationship, underlying its phenomena. We performed high throughput transcriptional and metabolic analysis and identified SMRT ablated DCs to have enhanced OXPHOS but reduced glycolysis, de novo FAS, and ß-oxidation upon TLR9-specific activation. Mechanistically, decreased mTOR expression favoured the reduced glycolytic rate and its induction with Mhy1485 lowered the secretory levels of inflammatory cytokines. Additionally, decreased Pdh expression and subdued acetyl-CoA levels gave an insight into the broken TCA cycle. Correspondingly, they were found to rewire the cycle by activating the anaplerotic glutamine catabolism and succinate oxidation to maintain the inflammatory status of the cell. Inhibition of succinate transport with DEBM in sync with mTOR induction drastically hampered the inflammatory response both at RNA and protein levels. To validate the same at the global mRNA level we did bulk RNA-seq to determine the differentially expressed genes in different experimental settings. The results thus obtained showed transcriptional dysregulation of inflammatory pathways in SMRT KD DCs with combined modulator treatment.