Manganese Utilization in Salmonella Pathogenesis: Beyond the Canonical Antioxidant Response

Area of Science:

• Microbiology
• Bacterial Pathogenesis
• Nutritional Immunity

Background:

• Bacterial pathogens and hosts compete for essential metal ions like manganese (Mn2+).
• Hosts employ nutritional immunity strategies, restricting Mn2+ availability in environments like the gastrointestinal tract.
• Salmonella Typhimurium employs sophisticated mechanisms to acquire and utilize Mn2+ despite host limitations.

Purpose of the Study:

• To elucidate the critical role of manganese (Mn2+) in Salmonella Typhimurium pathogenesis.
• To understand how Salmonella Typhimurium overcomes host-imposed Mn2+ restriction.
• To investigate the contribution of Mn2+-dependent enzymes to Salmonella's survival and virulence.

Main Methods:

• Analysis of Salmonella Typhimurium's metal import systems.
• Transcriptional and posttranscriptional regulatory mechanisms governing Mn2+ uptake.
• Biochemical assays to assess the function of Mn2+-cofactored enzymes.

Main Results:

• Salmonella Typhimurium possesses diverse metal importers to counteract Mn2+ limitation.
• Mn2+ acts as a crucial cofactor for enzymes involved in antioxidant defense and central metabolism.
• Mn2+ supports glycolysis, the reductive tricarboxylic acid cycle, and the pentose phosphate pathway.

Conclusions:

• Manganese (Mn2+) is essential for Salmonella Typhimurium's resistance to reactive oxygen species.
• Mn2+-dependent metabolic pathways are vital for Salmonella's ability to colonize the gut and establish systemic infections.
• Targeting Mn2+ acquisition or utilization presents a potential strategy against Salmonella infections.