Farnesysltransferase Inhibitor Prevents Burn Injury-Induced Metabolome Changes in Muscle

Abstract

Burn injury remains a significant public health issue worldwide. Metabolic derangements are a major complication of burn injury and negatively affect the clinical outcomes of severely burned patients. These metabolic aberrations include muscle wasting, hypermetabolism, hyperglycemia, hyperlactatemia, insulin resistance, and mitochondrial dysfunction. However, little is known about the impact of burn injury on the metabolome profile in skeletal muscle. We have previously shown that farnesyltransferase inhibitor (FTI) reverses burn injury-induced insulin resistance, mitochondrial dysfunction, and the Warburg effect in mouse skeletal muscle. To evaluate metabolome composition, targeted quantitative analysis was performed using capillary electrophoresis mass spectrometry in mouse skeletal muscle. Principal component analysis (PCA), partial least squares discriminant analysis (PLS-DA), and hierarchical cluster analysis demonstrated that burn injury induced a global change in metabolome composition. FTI treatment almost completely prevented burn injury-induced alterations in metabolite levels. Pathway analysis revealed that the pathways most affected by burn injury were purine, glutathione, β-alanine, glycine, serine, and threonine metabolism. Burn injury induced a suppressed oxidized to reduced nicotinamide adenine dinucleotide (NAD⁺/NADH) ratio as well as oxidative stress and adenosine triphosphate (ATP) depletion, all of which were reversed by FTI. Moreover, our data raise the possibility that burn injury may lead to increased glutaminolysis and reductive carboxylation in mouse skeletal muscle.

Keywords: burn injury; farnesyltransferase inhibitor; metabolomics; skeletal muscle.

Figure 1

PCA score scatter plot (A) and the heat map (B). (A) Principal component scores are plotted. Purple: Sham-Vehicle, Blue: Sham-FTI, Red: Burn-Vehicle, Green: Burn-FTI. (B) SV: Sham-Vehicle, SF: Sham-FTI, BV: Burn-Vehicle, BF: Burn-FTI.

Figure 2

PLS-DA score scatter plot. Blue diamond: Sham-Vehicle, Blue cross mark: Sham-FTI, Green plus mark: Burn-Vehicle, Red triangle: Burn-FTI.

Figure 3

The intersection of differential metabolites. Venn diagram illustrates the distribution of differential metabolites showing significantly (p < 0.05 by Wilcoxon test) modulated levels. Red, blue and green circles indicate differential metabolites between Sham-Vehicle vs. Burn-Vehicle, those between Sham-FTI vs. Burn-FTI, and those between Burn-Vehicle vs. Burn-FTI, respectively.

Figure 4

Volcano plot of altered metabolites between Sham-Vehicle and Burn-Vehicle. Metabolites with an absolute fold change (FC) > 1.2 and false discovery rate (FDR) < 0.10 are plotted. Red: FDR < 0.1, Grey: ≥ 0.1.

Figure 5

Effects of burn injury and FTI-277 on metabolites related to purine metabolism. SV: Sham-Vehicle; SF: Sham-FTI; BV: Burn-Vehicle; BF: Burn-FTI, Succinyl AMP: adenylosuccinic acid, * p < 0.05, ** p < 0.01, *** p < 0.001, **** p < 0.0001, § p < 0.05 vs. Sham-Vehicle, p < 0.001 vs. Burn-FTI, §§ p < 0.01 vs. Sham-Vehicle, p < 0.001 vs. Burn-FTI, ¶ p < 0.05 vs. Sham-FTI.

Figure 6

Effects of burn injury and FTI-277 on metabolites related to glutathione (A), β-alanine (B), glycine, serine, and threonine metabolism (C). SV: Sham-Vehicle; SF: Sham-FTI; BV: Burn-Vehicle; BF: Burn-FTI, GSH: reduced glutathione, GSSG: oxidized glutathione, * p < 0.05, ** p < 0.01, *** p < 0.001, **** p < 0.0001.

Figure 7

Effects of burn injury and FTI-277 on redox-related metabolites. SV: Sham-Vehicle; SF: Sham-FTI; BV: Burn-Vehicle; BF: Burn-FTI, *** p < 0.001, **** p < 0.0001.

Figure 8

Effects of burn injury and FTI-277 on metabolites related to the urea/ornithine cycle (A), creatine metabolism (B), and total amino acids (C). SV: Sham-Vehicle; SF: Sham-FTI; BV: Burn-Vehicle; BF: Burn-FTI, * p < 0.05, ** p < 0.01, *** p < 0.001, **** p < 0.0001, § p < 0.05 vs. Sham-FTI and Burn-FTI, ¶ p < 0.05 vs. Sham-FTI.

Figure 9

Effects of burn injury and FTI-277 on lactic acid and pyruvic acid. SV: Sham-Vehicle; SF: Sham-FTI; BV: Burn-Vehicle; BF: Burn-FTI, * p < 0.05, ** p < 0.01, *** p < 0.001, ¶ p < 0.05 vs. Sham + FTI.

Figure 10

Effects of burn injury and FTI-277 on glutamine, glutamate, and TCA cycle intermediates. SV: Sham-Vehicle; SF: Sham-FTI; BV: Burn-Vehicle; BF: Burn-FTI, * p < 0.05, ** p < 0.01, *** p < 0.001, **** p < 0.0001.