Infection and
inflammation are able to induce diet-independent Na+-accumulation without commensurate water retention in afflicted tissues, which favors the pro-inflammatory activation of mouse macrophages and augments their antibacterial and
antiparasitic activity. While Na+-boosted host defense against the protozoan parasite Leishmania major is mediated by increased expression of the leishmanicidal NOS2 (
nitric oxide synthase 2, inducible), the molecular mechanisms underpinning this enhanced antibacterial defense of mouse macrophages with high Na+ (HS) exposure are unknown. Here, we provide evidence that HS-increased antibacterial activity against E. coli was neither dependent on NOS2 nor on the phagocyte
oxidase. In contrast, HS-augmented antibacterial defense hinged on HIF1A (
hypoxia inducible factor 1, alpha subunit)-dependent increased autophagy, and NFAT5 (nuclear factor of activated T cells 5)-dependent targeting of intracellular E. coli to acidic autolysosomal compartments. Overall, these findings suggest that the autolysosomal compartment is a novel target of Na+-modulated cell autonomous innate immunity. Abbreviations: ACT:
actins; AKT: AKT
serine/threonine kinase 1; ATG2A: autophagy related 2A; ATG4C: autophagy related 4C,
cysteine peptidase; ATG7: autophagy related 7; ATG12: autophagy related 12; BECN1:
beclin 1; BMDM: bone marrow-derived macrophages; BNIP3: BCL2/adenovirus E1B interacting
protein 3; CFU: colony forming units; CM-
H2DCFDA: 5-(and-6)-chloromethyl-2',7'-dichlorodihydrofluorescein diacetate, acetyl
ester; CTSB:
cathepsin B; CYBB:
cytochrome b-245 beta chain;
DAPI: 4,6-diamidino-2-phenylindole; DMOG:
dimethyloxallyl glycine; DPI:
diphenyleneiodonium chloride; E. coli: Escherichia coli; FDR: false discovery rate; GFP:
green fluorescent protein; GSEA: gene set enrichment analysis; GO: gene ontology; HIF1A:
hypoxia inducible factor 1, alpha subunit; HUGO: human genome organization; HS: high
salt (+ 40 mM of NaCl to standard cell culture conditions); HSP90: heat shock 90 kDa
proteins; LDH:
lactate dehydrogenase; LPS:
lipopolysaccharide; Lyz2/LysM:
lysozyme 2; NFAT5/TonEBP: nuclear factor of activated T cells 5; MΦ: macrophages; MAP1LC3/LC3:
microtubule associated protein 1 light chain 3; MFI: mean fluorescence intensity; MIC: minimum inhibitory concentration; MOI: multiplicity of
infection; MTOR: mechanistic target of
rapamycin kinase; NaCl:
sodium chloride; NES: normalized enrichment score; n.s.: not significant; NO:
nitric oxide; NOS2/iNOS:
nitric oxide synthase 2, inducible; NS: normal
salt; PCR: polymerase chain reaction; PGK1:
phosphoglycerate kinase 1;
PHOX: phagocyte
oxidase; RFP:
red fluorescent protein;
RNA:
ribonucleic acid; ROS:
reactive oxygen species; sCFP3A: super
cyan fluorescent protein 3A;
SBFI:
sodium-binding benzofuran isophthalate; SLC2A1/GLUT1: solute carrier family 2 (facilitated
glucose transporter), member 1; SQSTM1/p62: sequestosome 1; ULK1: unc-51 like
kinase 1; v-
ATPase: vacuolar-type
H+-ATPase; WT: wild type.