Biophysical Society Thematic Meeting

Biophysics in the Understanding, Diagnosis, and Treatment of Infectious Diseases Poster Abstracts

27-POS

Board 27

Directing Warburg: Mycobacterium Tuberculosis Redirects Host Energy Metabolism in

the TB Lung

James Hove Mazorodze

, Bridgette Cumming

, Shannon Russell

, Jun Li

, Vikram Saini

Anna Moshnikova

, Yana Reshetnyak

, Oleg Andreev

, Joel Glasgow

, Adrie Steyn

1,2

K-RITH, Durban, KwaZulu Natal, South Africa,

University of Alabama at Birmingham,

Birmingham, AL, USA,

University of Rhode Island, Rhode Island, RI, USA.

The physiological consequences of hypoxia and acidosis in Mycobacterium tuberculosis (Mtb)

infection are poorly understood. We hypothesized that Mtb redirects host metabolism from

oxidative phosphorylation towards increased aerobic glycolysis (the “Warburg Effect”) resulting

in elevated lactate levels and extracellular acidity. To test this hypothesis, we used extracellular

flux analysis with an XF96 machine that measures oxygen consumption rate, as a measure of

oxidative phosphorylation and extracellular acidification rate as a measure of glycolysis. Mtb

infection induced a shift from oxidative phosphorylation to aerobic glycolysis. This shift induced

extracellular acidity as demonstrated using a fluorescently labelled pH (low) insertion peptide

(pHLIP). Mtb-infected mice were injected with fluorescently labelled pHLIP peptides and the

lungs examined ex vivo using near-infrared fluorescence (NIRF) imaging.

Immunohistochemistry was performed using antibodies against GLUT1 (a glucose transporter),

HIF-1α (hypoxia inducible factor), MCT4 (monocarboxylate transporter 4), LDHA (lactate

dehydrogenase A) and NHE1 (sodium hydrogen exporter 1). We used a metabolomics approach

to quantify intermediates of the glycolytic and tricarboxylic acid (TCA) cycle in Mtb-infected

and uninfected mice. Lastly, we measured differential expression of select genes involved in

glycolysis, TCA cycle, acidosis and hypoxia. We observed significantly increased fluorescence

intensity in lesions of Mtb-infected lungs compared to uninfected mice via NIRF imaging.

Immunostaining revealed increased levels of GLUT1, LDHA, MCT4, NHE1 and HIF-1α in Mtb-

infected vs uninfected mice. Further, select genes involved in glycolysis, TCA cycle, acidosis

and hypoxia were upregulated in Mtb-infected mice, consistent with immunohistochemistry and

pHLIP NIRF imaging. We conclude that Mtb results in a shift from host oxidative

phosphorylation to glycolysis, resulting in acidic extracellular pH changes due to accumulation

of lactate.