PRKAG2.2 is essential for FoxA1+ regulatory T cell differentiation and metabolic rewiring distinct from FoxP3+ regulatory T cells.

Forkhead box A1 (FoxA1)+ regulatory T cells (Tregs) exhibit distinct characteristics from FoxP3+ Tregs while equally effective in exerting anti-inflammatory properties. The role of FoxP3+ Tregs in vivo has been challenged, motivating a better understanding of other Tregs in modulating hyperactive immune responses. FoxA1+ Tregs are generated on activation of the transcription factor FoxA1 by interferon-ß (IFNß), an anti-inflammatory cytokine. T cell activation, expansion, and function hinge on metabolic adaptability. We demonstrated that IFNß promotes a metabolic rearrangement of FoxA1+ Tregs by enhancing oxidative phosphorylation and mitochondria clearance by mitophagy. In response to IFNß, FoxA1 induces a specific transcription variant of adenosine 5'-monophosphate-activated protein kinase (AMPK) γ2 subunit, PRKAG2.2. This leads to the activation of AMPK signaling, thereby enhancing mitochondrial respiration and mitophagy by ULK1-BNIP3. This IFNß-FoxA1-PRKAG2.2-BNIP3 axis is pivotal for their suppressive function. The involvement of PRKAG2.2 in FoxA1+ Treg, not FoxP3+ Treg differentiation, underscores the metabolic differences between Treg populations and suggests potential therapeutic targets for autoimmune diseases.

Corrigendum: Neuronal IFN-beta-induced PI3K/Akt-FoxA1 signalling is essential for generation of FoxA1+Treg cells.

This corrects the article DOI: 10.1038/ncomms14709.

Neuronal IFN-beta-induced PI3K/Akt-FoxA1 signalling is essential for generation of FoxA1+Treg cells.

Neurons reprogramme encephalitogenic T cells (Tenc) to regulatory T cells (Tregs), either FoxP3+Tregs or FoxA1+Tregs. We reported previously that neuronal ability to generate FoxA1+Tregs was central to preventing neuroinflammation in experimental autoimmune encephalomyelitis (EAE). Mice lacking interferon (IFN)-ß were defective in generating FoxA1+Tregs in the brain. Here we show that lack of neuronal IFNß signalling is associated with the absence of programme death ligand-1 (PDL1), which prevents their ability to reprogramme Tenc cells to FoxA1+Tregs. Passive transfer-EAE via IFNß-competent Tenc cells to mice lacking IFNß and active induced-EAE in mice lacking its receptor, IFNAR, in the brain (NesCre:Ifnarfl/fl) result in defective FoxA1+Tregs generation and aggravated neuroinflammation. IFNß activates neuronal PI3K/Akt signalling and Akt binds to transcription factor FoxA1 that translocates to the nucleus and induces PDL1. Conversely, inhibition of PI3K/Akt, FoxA1 and PDL1 blocked neuronal ability to generate FoxA1+Tregs. We characterize molecular factors central for neuronal ability to reprogramme pathogenic T cells to FoxA1+Tregs preventing neuroinflammation.

Screening of OATP1B1/3 and OCT1 inhibitors in cryopreserved hepatocytes in suspension.

Drug-drug interactions involving hepatic drug transporters may have clinical consequences and jeopardize development of promising drug candidates. Organic anion transporting polypeptides (OATP/Oatp) and the organic cation transporters (OCT/Oct) are among the most important transporters involved in xenobiotic uptake in the liver. In the present study, 179 molecules have been tested as inhibitors of the uptake of estradiol-17betaD-glucuronide (E(2)17betaG), substrate of OATP1B1/3 (rOatp), or 1-methyl-4-phenylpyridinium (MPP+), substrate of OCT1 (rOct1), into suspended cryopreserved hepatocytes from humans and rats. Uptake was assessed in 96-well plates by measuring intracellular accumulation of radioactive substrate in hepatocytes in presence or absence of inhibitor. In rat hepatocytes 140 compounds were identified as inhibitors (inhibition at 20 microM > or = 30%) of E(2)17betaG uptake and 77 compounds inhibitors of MPP+ uptake. The most potent inhibitors of rOatp and rOct1 were dantrolene sodium (K(i)=2 +/- 9 microM) and bepridil (K(i)=14 +/- 2 microM), respectively. In human hepatocytes, the most potent inhibitors of E(2)17betaG and MPP+ uptake were capsazepine (K(i)=14 +/- 5 microM) and cyproheptadine (K(i)=19+/-3 microM), respectively. Structure-activity relationship (SAR) analysis of all tested compounds suggested that lipophilicity, polarity, pK(a) and the number of hydrogen bond donors and acceptors play a role in their interaction with the transporters investigated. The method used here is a simple tool to screen large number of compounds as inhibitors of the uptake of substrates into suspended hepatocytes.