SLC11A2 affects nutritional immunity in the gut epithelium

Area of Science:

• Microbiology
• Immunology
• Gastroenterology

Background:

• Pathogen-host interactions involve competition for essential trace metals.
• Nutritional immunity is a host defense strategy to limit metal availability to pathogens.
• Intestinal epithelial cells (IECs) play a role in metal absorption and are targets for enteric pathogens.

Purpose of the Study:

• To investigate the role of IEC-intrinsic factors in nutritional immunity against enteric pathogens.
• To map the spatiotemporal dynamics of metal competition during Salmonella infection in the intestine.
• To determine the contribution of the metal transporter SLC11A2 in IECs to host defense.

Main Methods:

• Utilized Salmonella enterica serovar Typhimurium (STm) with metal-responsive fluorescent reporters in a bovine ligated intestinal loop model.
• Employed gene knockout models of SLC11A2 in IECs.
• Used fluorescence-based biosensors and bacterial gene deletion mutants to pinpoint specific metal restrictions.

Main Results:

• STm experienced temporal and cell-specific restriction of iron, manganese, and zinc in the intestinal mucosa early in infection.
• Knockout of SLC11A2 in IECs resulted in enhanced STm replication, indicating a protective role for the transporter.
• Manganese and iron restriction were identified as the mechanisms by which SLC11A2 limits bacterial proliferation.

Conclusions:

• SLC11A2-mediated metal sequestration is an intrinsic defense mechanism of the intestinal epithelium.
• This epithelial defense limits the proliferation of enteric bacteria like Salmonella.
• Understanding these mechanisms can inform strategies against gastrointestinal infections.