Control of regulatory T cell function by the non-oxidative pentose phosphate pathway [RNA-Seq]

Non-oxidative pentose phosphate pathway (PPP) is a crucial gatekeeper of glucose catabolism in metabolic tissues. However, its role in regulatory T cells (Tregs) remains unknown. Here we report deleting transketolase (TKT), an indispensable enzyme of non-oxidative PPP, in Tregs caused a fatal auto-immune disease in mice. TKT deletion impaired suppressive capability without disturbing Treg cell number. Mechanistically, TKT deficiency caused Treg metabolic remodeling with decreased glucose catabolism, activated fatty acid and amino acid catabolism and uncontrolled oxidative phosphorylation. Moreover, excessive ammonia from deregulated amino acid catabolism impaired mitochondrial fitness while reduced α-ketoglutarate/succinate ratio led to DNA hypermethylation, limiting functional gene expression and suppressive activity of TKT-deficient Tregs. Therefore, our study identifies non-oxidative PPP as a new pathway for controlling Treg function. CD4+CD25+YFP+ Tregs were isolated from 7-week-old female chimeric WT and chimeric cKO mice (n=3 per group). Total RNA was isolated from Tregs and used for RNA sequencing analysis by the Illumina HiSeq X Ten platform. In detail, mRNA was first randomly interrupted using divalent cations in NEB Fragmentation Buffer, then used to prepare libraries with the NEBNext Ultra RNA Library Prep Kit (New England Biolabs, Ipswich, MA), and finally sequenced using the Illumina HiSeq X Ten platform.