TFEB induces mitochondrial itaconate synthesis to suppress bacterial growth in macrophages

Abstract

Successful elimination of bacteria in phagocytes occurs in the phago-lysosomal system, but also depends on mitochondrial pathways. Yet, how these two organelle systems communicate is largely unknown. Here we identify the lysosomal biogenesis factor transcription factor EB (TFEB) as regulator for phago-lysosome-mitochondria crosstalk in macrophages. By combining cellular imaging and metabolic profiling, we find that TFEB activation, in response to bacterial stimuli, promotes the transcription of aconitate decarboxylase (Acod1, Irg1) and synthesis of its product itaconate, a mitochondrial metabolite with antimicrobial activity. Activation of the TFEB–Irg1–itaconate signalling axis reduces the survival of the intravacuolar pathogen Salmonella enterica serovar Typhimurium. TFEB-driven itaconate is subsequently transferred via the Irg1-Rab32–BLOC3 system into the Salmonella-containing vacuole, thereby exposing the pathogen to elevated itaconate levels. By activating itaconate production, TFEB selectively restricts proliferating Salmonella, a bacterial subpopulation that normally escapes macrophage control, which contrasts TFEB’s role in autophagy-mediated pathogen degradation. Together, our data define a TFEB-driven metabolic pathway between phago-lysosomes and mitochondria that restrains Salmonella Typhimurium burden in macrophages in vitro and in vivo.

Salmonellaactively modulates TFEB in murine macrophages in a growth-phase and time-dependent manner

“…4A, B). This result was not expected and may reflect a change in phosphorylation sites without a net change in number of phosphorylated residues of TFEB and/or heterogeneous infection rates that is not resolvable by a population-based assay such as Western blotting (Puertollano et al ., 2018), or may suggest that TFEB is regulated through another mechanism such as the recently discovered itaconate modification of TFEB (Zhang et al ., 2022; Schuster et al ., 2022). Interestingly, the levels of total TFEB normalized to actin were reduced in macrophages infected for 4 h with late-log-phase Salmonella , indicating that under specific conditions, Salmonella can repress TFEB expression or promote its degradation (Fig.…”

“…Additionally, host macrophages engage a TFEB-Irg1-itaconate signalling axis in response to Salmonella , whereby TFEB promotes Irg1-driven itaconate production. Itaconate then alkylates and promotes TFEB nuclear translocation, which helps restrict Salmonella survival (Zhang et al ., 2022; Schuster et al ., 2022). As described, the activation of TFEB is macrophage-driven.…”

Mycobacterial acyl carrier protein suppresses TFEB activation and upregulates miR-155 to inhibit host defense

“…Thus, the AcpM’s role in the suppression of antimicrobial responses against Mtb infection seems to be associated with the inhibition of TFEB, but not directly related to the suppression of autophagy. In addition, a recent study revealed that TFEB activation is required for the induction of mitochondrial itaconate synthesis to control intracellular bacterial growth ( 44 , 45 ), suggesting the critical function of TFEB in terms of antimicrobial defense in macrophages. Future studies will clarify whether AcpM is involved in the regulation of immunometabolic remodeling in macrophages to further affect TFEB-induced antimicrobial responses during Mtb infection.…”

The role of immunomodulatory metabolites in shaping the inflammatory response of macrophages

“…For example, Schuster et al . reported TFEB as a transcription factor for IRG expression, which is critical for removing intravacuolar pathogen Salmonella Enterica Serovar Typhimurium ( 85 ). Physiologically relevant carbon source for itaconate synthesis has also been explored in a comprehensive tracing analysis showing glucose and glutamine as major fuels for itaconate production ( 27 ).…”