421 Allogeneic T Cells up-Regulate Fatty Acid Metabolism and Can Be Targeted Through Metabolic Inhibition of Fatty Acid Oxidation

Track: Contributed Abstracts
Saturday, February 16, 2013, 6:45 PM-7:45 PM
Hall 1 (Salt Palace Convention Center)
Craig A Byersdorfer, M.D., Ph.D. , Blood and Marrow Transplant Program, University of Michigan, Ann Arbor, MI
Victor Tkachev, PhD , Department of Pediatrics, University of Michigan, Ann Arbor, MI
Stefanie Goodell , Department of Pediatrics, University of Michigan, Ann Arbor, MI
Stacy Sandquist , Department of Pediatrics, University of Michigan, Ann Arbor, MI
Anthony W Opipari, MD , Department of Obstetrics and Gynecology, University of Michigan, Ann Arbor, MI
Gary D Glick, PhD , Department of Chemistry, University of Michigan, Ann Arbor, MI
James L.M. Ferrara, M.D., D.Sc. , Blood and Marrow Transplant Program, University of Michigan, Ann Arbor, MI
Recent research has increased our understanding of lymphocyte metabolism in vitro, but the metabolism of lymphocytes activated in vivo remains poorly understood.  To evaluate this important issue further, we explored the metabolism of proliferating, donor T lymphocytes seven days after the initiation of graft versus-host disease (GVHD) in an acute model of GVHD (B6 into B6D2F1).  Donor T cells up-regulated mRNA for fatty acid (FA) transport proteins (e.g. SLC27a2) 40-fold and increased FA transport 4-fold compared to resting (naïve) T cells (see table).  Donor T cells also increased levels of enzymes necessary for FA oxidation (e.g. CPT2) 100-fold and oxidized more FAs.  Mitochondrial mass (required for FA oxidation) increased in donor T cells, as did the ratio of mitochondrial to nuclear DNA, and the expression of PGC-1α, a key regulator of mitochondrial biogenesis.  Importantly, T cells proliferating during routine immune reconstitution (following syngeneic BMT) minimally increased FA transport (10% vs. 40% in GVHD T cells).  Finally, inhibition of FA oxidation in vivo, through irreversible blockade of CPT1 with etomoxir, decreased the total number of well-divided donor T cells after a single dose.  Furthermore, two weeks of etomoxir treatment, beginning on day +7, improved both GVHD clinical score (1.1 vs. 3.8 in untreated animals, p=0.02) and weight loss at day 40.  In total, these data demonstrate that GVHD T cells up-regulate FA metabolism in vivo and that proliferating, donor cells can be selectively eliminated through inhibition of FA oxidation.  Our data provide novel insights into the metabolism of lymphocytes activated in vivo and show that inhibition of FA oxidation may be a therapeutic target for the prevention and/or treatment of GVHD.

Table. Fatty acid transport, oxidation, and mitochondrial biogenesis in GVHD T cells

Parameter

Naïve*

GVHD

p value

 

Fatty Acid Transport

 

 

 

Slc27a2 mRNA

1.0
± 0.8

42.0
± 6.7

0.04

Transport (% cells BoDipyHi)a

0.7
± 0.05

44.3
± 6.9

0.003

 

Fatty Acid Oxidation

 

 

 

CPT2 enzyme ratio

1.0
± 1.7

103
± 31

0.005

Oxidation (cpm x10-5)b

1.1
± 0.2

1.9
± 0.3

0.02

 

Mitochondrial Biogenesis

 

 

 

Mitochondrial Massc

47.6
± 14.2

66.3
± 5.9

0.04

Mitochondrial/nuclear DNA

1.0
± 0.07

2.7
± 0.52

< 0.0001

PGC-1α ratio

1.0
± 1.3

3900
± 1200

0.005

*Naïve cells served as controls (values set to 1.0) for mRNA levels and all ratios

aUptake of BoDipyC1-C12, a fatty acid analog, was measured by flow cytometry

bOxidation measured by the conversion of 3H-palmitate to 3H20, expressed as cpm of 3H2O

cMitochondrial mass measured as the % of cells Mitotracker GreenHi

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