Gluconeogenesis, an essential metabolic pathway for pathogenic Francisella

Area of Science:

• Microbiology
• Bacterial Pathogenesis
• Metabolic Pathways

Background:

• Francisella tularensis is an infectious pathogen requiring host nutrients for intracellular growth.
• Understanding bacterial metabolism is crucial for identifying virulence factors and therapeutic targets.

Purpose of the Study:

• To investigate the role of gluconeogenesis in Francisella tularensis pathogenesis.
• To determine the essentiality of the glpX gene and its encoded enzyme in bacterial survival and virulence.

Main Methods:

• Gene inactivation of glpX, encoding fructose 1,6-bisphosphatase.
• Assessing bacterial intracellular multiplication with gluconeogenic substrates (glycerol, pyruvate).
• Evaluating virulence in a mouse model.
• Utilizing isotopic profiling to analyze metabolic pathways (Embden-Meyerhof/glycolysis and gluconeogenesis).

Main Results:

• Inactivation of glpX significantly impaired intracellular bacterial multiplication when gluconeogenic substrates were available.
• The ΔglpX mutant exhibited a severe virulence defect in vivo.
• Isotopic profiling confirmed glpX's role in gluconeogenesis and highlighted glycolysis's importance in glucose metabolism.

Conclusions:

• Gluconeogenesis is an essential metabolic pathway for Francisella tularensis pathogenesis.
• The glpX gene is critical for virulence, likely enabling the pathogen to utilize host-derived nutrients during infection.
• Targeting the gluconeogenic pathway presents a potential therapeutic strategy against Francisella tularensis infections.