Arteriovenous metabolomics in pigs reveals CFTR regulation of metabolism in multiple organs
Hosung Bae, Bo Ram Kim, Sunhee Jung, Johnny Le, Dana van der Heide, Wenjie Yu, Sang Hee Park, Brieanna M. Hilkin, Nicholas D. Gansemer, Linda S. Powers, Taekyung Kang, David K. Meyerholz, Victor L. Schuster, Cholsoon Jang, Michael J. Welsh
Hosung Bae, Bo Ram Kim, Sunhee Jung, Johnny Le, Dana van der Heide, Wenjie Yu, Sang Hee Park, Brieanna M. Hilkin, Nicholas D. Gansemer, Linda S. Powers, Taekyung Kang, David K. Meyerholz, Victor L. Schuster, Cholsoon Jang, Michael J. Welsh
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Research Article Metabolism

Arteriovenous metabolomics in pigs reveals CFTR regulation of metabolism in multiple organs

Abstract

Mutations in the cystic fibrosis transmembrane conductance regulator (CFTR) gene cause cystic fibrosis (CF), a multiorgan disease that is characterized by diverse metabolic defects. However, other than specific CFTR mutations, the factors that influence disease progression and severity remain poorly understood. Aberrant metabolite levels have been reported, but whether CFTR loss itself or secondary abnormalities (infection, inflammation, malnutrition, and various treatments) drive metabolic defects is uncertain. Here, we implemented comprehensive arteriovenous metabolomics in newborn CF pigs, and the results revealed CFTR as a bona fide regulator of metabolism. CFTR loss impaired metabolite exchange across organs, including disruption of lung uptake of fatty acids, yet enhancement of uptake of arachidonic acid, a precursor of proinflammatory cytokines. CFTR loss also impaired kidney reabsorption of amino acids and lactate and abolished renal glucose homeostasis. These and additional unexpected metabolic defects prior to disease manifestations reveal a fundamental role for CFTR in controlling multiorgan metabolism. Such discovery informs a basic understanding of CF, provides a foundation for future investigation, and has implications for developing therapies targeting only a single tissue.

Authors

Hosung Bae, Bo Ram Kim, Sunhee Jung, Johnny Le, Dana van der Heide, Wenjie Yu, Sang Hee Park, Brieanna M. Hilkin, Nicholas D. Gansemer, Linda S. Powers, Taekyung Kang, David K. Meyerholz, Victor L. Schuster, Cholsoon Jang, Michael J. Welsh

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Figure 6

Inhibition of CFTR in cultured human renal proximal tubule epithelia impairs amino acid absorption.

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Inhibition of CFTR in cultured human renal proximal tubule epithelia imp...
(A) H&E staining of newborn WT and CF pig kidneys. Scale bars: 50 μm. (B) Volcano plot showing differentially expressed genes in WT and CF pig kidneys. lnFC, fold change (CF/WT) in kidney tissues at the natural log scale. Dashed lines indicate the cutoffs: genes that were lower in CF with P < 0.05, by Mann-Whitney U test are highlighted in red. n = 12 WT and 11 CF pigs. Down, downregulated; Up, upregulated. (C) Immunofluorescence staining for CFTR (green) and actin (white) in DAPI-labeled human renal proximal tubule epithelial cells. Scale bars: 20 μm (left 2 panels) and 100 μm (right-most panel). (D and E) Rt and Vt in cells after addition of vehicle control or 2 CFTR inhibitors (CFTRinh-172 or GlyH-101). n = 6 per group for Rt and n = 9 per group for voltage. Bars show the mean ± SD. *P < 0.05 and **P < 0.01, by 1-way ANOVA. (F) Schematic of an assay to measure transepithelial transport of amino acids. (G and H) Percentage change in transepithelial transport of amino acids by CFTR inhibitors at 60 minutes after amino acid addition. Mannitol was used as a negative control. #P < 0.1, *P < 0.05, and **P < 0.01 for color-coded inhibitors relative to vehicle, by Mann-Whitney U test. Bars show the mean ± SD. n = 6 per group, except n = 5 for valine, asparagine, tryptophan, mannitol, and 13C-glutamate. (I) Proposed model for impaired amino acid reabsorption by the proximal tubule. Cl– absorption through CFTR anion channels contributes to the lumen positive voltage, and loss of CFTR decreases voltage. The positive voltage enhances Na+- and H+-coupled amino acid reabsorption.