Gfpt2 modulates fibroblast activation by glutathione metabolism

Fibrosis is a maladaptive process common to many diseases throughout the human body. During fibroblast activation, the cell undergoes metabolic reprogramming to increase glycolysis and support increased cellular growth. Alterations in metabolism have been shown to play a significant role in determining cell identity and function. However, the contribution of many ancillary metabolic pathways in cardiac fibroblasts remains poorly defined. Here we investigate the role of Gfpt2, the rate-limiting enzyme of the hexosamine biosynthesis pathway, and metabolism in fibroblast activation. We demonstrate loss of Gfpt2 in cardiac fibroblasts results in a shift towards an activated fibroblast phenotype suggesting Gfpt2 acts as a regulator of fibroblast activation. Furthermore, untargeted metabolomics identifies glutathione metabolism as a downstream pathway and shows decreased glutathione following Gfpt2 loss. Consistent with this result, treatment with glutathione following either Gfpt2 knockdown or TGFβ stimulation is sufficient to prevent fibroblast activation. Finally, screening fibroblasts from other tissues illustrates that the Gfpt2-glutathione regulatory axis is shared across some, but not all, tested fibroblast populations. Overall, our study highlights the nuanced role of metabolism in cardiac fibroblasts and identifies a novel regulatory axis that could be a shared pathway in fibroblast activation.