Gluconeogenic carbon flow of tricarboxylic acid cycle intermediates is critical for Mycobacterium tuberculosis to establish and maintain infection

Abstract

Metabolic adaptation to the host niche is a defining feature of the pathogenicity of Mycobacterium tuberculosis (Mtb). In vitro, Mtb is able to grow on a variety of carbon sources, but mounting evidence has implicated fatty acids as the major source of carbon and energy for Mtb during infection. When bacterial metabolism is primarily fueled by fatty acids, biosynthesis of sugars from intermediates of the tricarboxylic acid cycle is essential for growth. The role of gluconeogenesis in the pathogenesis of Mtb however remains unaddressed. Phosphoenolpyruvate carboxykinase (PEPCK) catalyzes the first committed step of gluconeogenesis. We applied genetic analyses and 13 C carbon tracing to confirm that PEPCK is essential for growth of Mtb on fatty acids and catalyzes carbon flow from tricarboxylic acid cycle-derived metabolites to gluconeogenic intermediates. We further show that PEPCK is required for growth of Mtb in isolated bone marrow-derived murine macrophages and in mice. Importantly, Mtb lacking PEPCK not only failed to replicate in mouse lungs but also failed to survive, and PEPCK depletion during the chronic phase of infection resulted in mycobacterial clearance. Mtb thus relies on gluconeogenesis throughout the infection. PEPCK depletion also attenuated Mtb in IFNγ-deficient mice, suggesting that this enzyme represents an attractive target for chemotherapy.carbon metabolism | gluconeogenesis | metabolomics | microbial pathogenesis | phosphoenolpyruvate carboxykinase

Discovery of a glycerol 3-phosphate phosphatase reveals glycerophospholipid polar head recycling in Mycobacterium tuberculosis

“…Fatty acid catabolism is well documented in M. tuberculosis. Glycerophospholipid catabolism provides lipid polar heads and fatty acids, which could be degraded through β-oxidation, generating energy and biosynthetic precursors via Krebs and glyoxylate cycles and gluconeogenesis (32)(33)(34)(35). Glycerophospholipid turnover has also been verified in related species, such as Mycobacterium smegmatis and Mycobacterium phlei (36).…”

The pleiotropic transcriptional response of Mycobacterium tuberculosis to vitamin C is robust and overlaps with the bacterial response to multiple intracellular stresses

“…Genes such as pckA, coding for phosphoenolpyruvate carboxykinase of the gluconeogenesis pathway, and icl, encoding isocitrate lyase of the glyoxylate pathway, were upregulated. These genes are upregulated in lung infection in mice (McKinney et al, 2000), and it has been established recently that gluconeogenic carbon flow of tricarboxylic acid cycle intermediates is critical to establish and maintain Mtb infection (Marrero et al, 2010).…”

Succinylome Analysis Reveals the Involvement of Lysine Succinylation in Metabolism in Pathogenic Mycobacterium tuberculosis*

“…To achieve these different physiologic states, Mtb developed a mechanism to sense diverse signals from the host and to coordinately regulate multiple cellular processes and pathways (30,31). Mtb has evolved its metabolic network to both maintain and propagate its survival as a species within humans (32)(33)(34)(35). It is well accepted that metabolic network is a central mediator and defining feature of the pathogenicity of Mtb (23, 36 -38).…”