Glutamine Fuels the Progress of Lupus Nephritis - Understanding from Metabolomics, Epigenetics to Immunopathogenesis

Lupus nephritis, one of the most serious manifestations of systemic lupus erythematosus was seen in up to 60% of cases with SLE. Since SLE resulted from autoimmune dis-regulation, for those with lupus nephritis, immune modulation may be their life-saving straw.Regulatory T cells (Treg) play a crucial role in limiting the aberrant immune responses. On the other hand, Th17 lineage, an effector CD4(+) T cells characterized by the production of IL-17, has been implicated in autoimmune disease. Immune cell activation and differentiation occurs at the same time with metabolic reprogramming. According to our preliminary data, glutamine deprivation mitigates Th17 development and augments Foxp3+ cell development. Therefore, we will investigate the role of glutamine deprivation in modulating Treg and Th17 polarization by metabolomics and epigenetics appraoch. We then propose a novel therapeutic strategy of using glutaminase inhibitors in attempt to improve control of lupus nephritis.Glutamine providing both carbon and nitrogen sources for anabolic metabolism is crucial for highly proliferative cells such as cancer cells and effector T cells. How glutamine modulates T cell subsets via metabolomic and epigenetic regulation remains an open question. Firstly, we will exam the transcriptome, H3K4me3, H3K9me3, H3K27ac and ATAC-seq modification regulated by glutamine deprivation in Treg and Th17. We then will investigate how epigenetic change of Foxp3 promotor in glutamine free (GF) condition associated with suppression ability and co-inhibitory markers. We will also explore the role of role of fatty acid on reprogramming of metabolic pathways in GF condition and associated ROS on FOXP3 induction. Moreover, to clarify the metabolic regulation of Treg and Th17 by glutamine deprivatrion, we will analyze metabolite of Th17 polarization with GF medium added by glutamine at different time point by mass spectrometry, which will be correlated with epigenetic modification. Finally, according to the crucial role of glutaminase for glutamine metabolism, we will initiate high throughput screening for glutaminase inhibitor. We will apply glutamine inhibitor in prestane induced lupus murine model on HIF-1 reporter mice and then access autoantibodies and cells in their circulation, spleen, and kidney to evaluate treatment response by a FACSymphonyTM and single cell RNA-sequencing. In sum, this proposal will be the very first study focusing on how glutamine deprivation mediate epigenetic and metabolomic modulation in Treg and Th17. After identifying the glutaminase inhibitors, we then will treat lupus murine model with glutaminase inhibitor to monitor treatment response for future clinical application as a novel therapy.Year 1. To determine the impact of glutamine on epigenetic and metabolomic change of CD4 T cell subsets in vitro and in vivo. A HIF-1a in vivo reporter mice and high throughput screening for glutaminase inhibitors will also be built.Year 2. To understand how glutamine modulate regulatory T cell by the association between epigenetic change of foxp3 promotor and fatty acid metabolism.Year 3. To investigate whether glutaminase inhibitors will help immune tolerance in lupus model by immunophenotyping and single cell RNA sequencing.

Project ID:PC10907-1541
External Project ID:MOST109-2314-B182-054-MY3