Significance of Short Chain Fatty Acid Transport by Members of the Monocarboxylate Transporter Family (MCT)
Metabolism of short-chain fatty acids (SCFA) in the brain, particularly that of acetate, appears to occur mainly in astrocytes. The differential use has been attributed to transport, but the extent to which transmembrane movement of SCFA is mediated by transporters has not been investigated systematically. Here we tested the possible contribution of monocarboxylate transporters to SCFA uptake by measuring fluxes with labelled compounds and by following changes of the intracellular pH in Xenopus laevis oocytes expressing the isoforms MCT1, MCT2 or MCT4. All isoforms mediated significant transport of acetate. Formate, however, was transported only by MCT1. The contribution of MCT1 to SCFA transport was determined by using phloretin as a high-affinity inhibitor, which allowed a paired comparison of oocytes with and without active MCT1.
KeywordsAstrocytes Acetate Short-chain fatty acids Non-ionic diffusion
- 25.Whitaker-Menezes D, Martinez-Outschoorn UE, Lin Z, Ertel A, Flomenberg N, Witkiewicz AK, Birbe RC, Howell A, Pavlides S, Gandara R, Pestell RG, Sotgia F, Philp NJ, Lisanti MP (2011) Evidence for a stromal-epithelial “lactate shuttle” in human tumors: MCT4 is a marker of oxidative stress in cancer-associated fibroblasts. Cell Cycle 10:1772–1783PubMedCrossRefGoogle Scholar
- 28.Broer S, Rahman B, Pellegri G, Pellerin L, Martin JL, Verleysdonk S, Hamprecht B, Magistretti PJ (1997) Comparison of lactate transport in astroglial cells and monocarboxylate transporter 1 (MCT 1) expressing Xenopus laevis oocytes. Expression of two different monocarboxylate transporters in astroglial cells and neurons. J Biol Chem 272:30096–30102PubMedCrossRefGoogle Scholar