Premium
Metabolic Stress Drives Keratinocyte Defenses Against Staphylococcus aureus Infection
Author(s) -
Wickersham Matthew Adam,
Wachtel Sarah,
Lung Tania Wong Fok,
Jacquet Rudy,
Soong Grace,
Richardson Anthony,
Parker Dane,
Prince Alice
Publication year - 2017
Publication title -
the faseb journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.709
H-Index - 277
eISSN - 1530-6860
pISSN - 0892-6638
DOI - 10.1096/fasebj.31.1_supplement.622.4
Subject(s) - keratinocyte , glycolysis , staphylococcus aureus , biology , hif1a , microbiology and biotechnology , anaerobic glycolysis , pi3k/akt/mtor pathway , metabolic pathway , signal transduction , angiogenesis , cancer research , in vitro , biochemistry , metabolism , bacteria , genetics
OBJECTIVE Human skin is commonly colonized and infected by Staphylococcus aureus . Under normal conditions skin is relatively hypoxic. Thus, we postulated that the burden of staphylococcal infection would result in competition for glucose and stimulation of HIF1a signaling to initiate keratinocyte metabolic and immune responses to infection. METHODS The metabolic activity of primary keratinocytes in response S. aureus metabolic mutants was monitored using a SeaHorse analyzer to measure oxygen consumption and extracellular acidification. A transcriptomic analysis of keratinocyte responses to S . aureus USA300 infected keratinocytes was performed and key results were confirmed by qRT‐PCR and immunoblot. The immunological consequences of Hif1a signaling were demonstrated in vitro, as the metabolic and inflammatory activities of primary keratinocytes were studied through qRT arrays, western blots, ELISA assays and confocal imaging. The in vivo consequences of the glycolytic response to infection were confirmed in vivo in a murine model of skin infection. ABSTRACT Using a combination of metabolic and transcriptomic methodologies, we found that S. aureus infection is sensed as a metabolic stress by keratinocytes. This is sufficient to induce HIF1a signaling, which promotes IL‐1b production and generates components of the aerobic glycolysis pathway to meet the metabolic requirements of infection. Staphylococci capable of glycolysis, including WT and agr mutants readily induced HIF1a. In contrast, pyk glycolytic mutants failed to compete with keratinocytes for their metabolic needs. Although S. aureus activate the Akt/mTOR cascade, inhibition of this pathway did not inhibit the keratinocyte cytokine response to infection. However, 2‐DG mediated suppression of glycolysis blocked keratinocyte production of IL‐1b in vitro and significantly exacerbated the S. aureus cutaneous infection in a murine model. CONCLUSIONS S. aureus is perceived as a metabolic stress by infected keratinocytes. These keratinocytes respond through HIF1a signaling, increasing glycolytic activity and generating IL‐1b. S. aureus glycolytic mutants, independent of toxin production, fail to activate keratinocytes. Support or Funding Information FUNDING: The results presented in this abstract were supported by the National Institutes of Health under award number RO1AI103854.