Fig 1: TMAO normalizes GLT-mediated reduction of the IRE1a unfolded protein response (UPR) in INS-1 ß-cells. INS-1 ß-cells cultured with or without 40 µM TMAO for 24 in SCC and GLT were measured for changes to UPR pathway proteins by Western blotting and mRNA by qPCR. Samples were probed and quantified for p-PERK (170kd) and PERK (140kd) (A–C), ATF4 (39kd) (D,E), IRE1a (130kd) (F,G), sXBP1 (40kd) and uXBP1 (29kd) (J–M). mRNA of sXBP1 and total XBP1 were measured by qPCR (H,I). Abbreviations: quantitative polymerase chain reaction (qPCR), phospho-protein kinase RNA-like ER kinase (p-PERK), activating transcription factor (ATF4), inositol-requiring enzyme 1a (IRE1a) (A,B), spliced and unspliced X-box bind protein 1 (sXBP1, uXBP1). All Western blot values are normalized to the loading control tubulin and represent the mean of biological triplicates (n = 3). qPCR data represent the mean of 6 to 8 replicates (n = 6–8). Error bars indicate the standard error. * Indicates significant one-way ANOVA showing GLT and TMAO effects, where p-values <0.1 given, * <0.05, ** <0.01, *** <0.001, **** <0.0001, or ns.