Mice Lacking Fatty Acid-Binding Protein 5 Are Resistant to Listeria monocytogenes

To investigate the role of fatty acid-binding protein 5 (FABP5) in infectious diseases, FABP5-deficient mice were challenged with Listeria monocytogenes, a facultative intracellular bacterial pathogen. Interestingly, FABP5-deficient animals were able to clear the infection within 3 days whereas control wild-type (WT) animals showed comparatively higher bacterial burdens in the liver and spleen. Sections of infected tissues showed an increase in inflammatory foci in WT mice compared to FABP5-deficient mice. FABP5-deficient mice had lower circulating inflammatory cytokines and increased inducible nitric oxide synthase production. FABP5-deficient mouse bone marrow-derived macrophages produced higher levels of nitrite anion than their WT counterparts in response to various stimuli. Additionally, in contrast to FABP5-/- mice, transgenic mice overexpressing FABP5 in myeloid cells (LysM-Cre driven) showed decreased survival rates and increased bacterial burden and inflammatory cytokines. Overall, these findings suggest that increased FABP5 levels correlate with a higher L. monocytogenes bacterial burden and elevated subsequent inflammation.