evaluation-of-lung-function-in-an-ex-vivo-murine-model

Evaluation of Lung Function in an <em>Ex vivo</em> Murine Model

Respiratory mechanics are a key area of study in defining and treating lung pathologies by assessing functional lung capacity. Lung mechanics can be ...

Medical University of South Carolina

Activated T cells undergo metabolic reprogramming to meet anabolic, differentiation, and functional demands. Glutamine supports many processes in activated T cells, and inhibition of glutamine metabolism alters T cell function in autoimmune disease and cancer. Multiple glutamine-targeting molecules are under investigation, yet the precise mechanisms of glutamine-dependent CD8 T cell differentiation remain unclear. We show that distinct strategies of glutamine inhibition by glutaminase-specific inhibition with small molecule CB-839, pan-glutamine inhibition with 6-diazo-5-oxo-l-norleucine (DON), or by glutamine-depleted conditions (No Q) produce distinct metabolic differentiation trajectories in murine CD8 T cells. T cell activation with CB-839 treatment had a milder effect than did DON or No Q treatment. A key difference was that CB-839-treated cells compensated with increased glycolytic metabolism, whereas DON and No Q-treated cells increased oxidative metabolism. However, all glutamine treatment strategies elevated CD8 T cell dependence on glucose metabolism, and No Q treatment caused adaptation toward reduced glutamine dependence. DON treatment reduced histone modifications and numbers of persisting cells in adoptive transfer studies, but those T cells that remained could expand normally upon secondary Ag encounter. In contrast, No Q-treated cells persisted well yet demonstrated decreased secondary expansion. Consistent with reduced persistence, CD8 T cells activated in the presence of DON had reduced ability to control tumor growth and reduced tumor infiltration in adoptive cell therapy. Overall, each approach to inhibit glutamine metabolism confers distinct effects on CD8 T cells and highlights that targeting the same pathway in different ways can elicit opposing metabolic and functional outcomes.

Differential Effects of Glutamine Inhibition Strategies on Antitumor CD8 T Cells.

Lymphodepleting pre-conditioning is a nearly universal component of T cell adoptive transfer protocols. The side effects of pre-conditioning regimens used in adoptive cell therapy are clinically significant and include pan-cytopenia, immune suppression, and reactive myelopoiesis. We conducted studies to test the hypothesis that the mechanisms underlying effective engraftment are cell autonomous and not dependent on a lymphodepleted host immune status. These studies leveraged mouse models to examine the role of Stat5 signaling during T cell adoptive transfer. We observed that, by transiently expressing a constitutively active mutamer of Stat5b during the process of adoptive transfer, we could completely obviate the need for lymphodepletion prior to adoptive transfer. Using several functional assays, we benchmark the function of the engrafted T cells against T cells transferred after conventional lymphodepletion. These studies identify a cell-autonomous mechanism driven by transient Stat5b signaling with lasting effects on T cell phenotype and function. Furthermore, the results presented suggest that adoptive T cell therapy could be improved by removing lymphodepletion protocols entirely and replacing them with RNA transfection of T cells with transcripts encoding active Stat5.

Efficient T cell adoptive transfer in lymphoreplete hosts mediated by transient activation of Stat5 signaling.

In this chapter, the methodologies are outlined for generating CAR-T from PBMCs using transposon engineering. Additionally, some methods and guidance related to basic functional and phenotypic analysis are described. This methodology can be applied to manufacture and assess chimeric antigen receptors for preclinical applications targeting a variety of molecules.

Transposon-Based Manufacturing of Human CAR-T Cells.

Stevens-Johnson syndrome and toxic epidermal necrolysis (SJS/TEN) is a rare but life-threatening cutaneous drug reaction mediated by human leukocyte antigen (HLA) class I-restricted CD8+ T-cells. To obtain an unbiased assessment of SJS/TEN cellular immunopathogenesis, we performed single-cell (sc) transcriptome, surface proteome, and TCR sequencing on unaffected skin, affected skin, and blister fluid from 17 SJS/TEN patients. From 119,784 total cells, we identified 16 scRNA-defined subsets, confirmed by subset-defining surface protein expression. Keratinocytes upregulated HLA and IFN-response genes in the affected skin. Cytotoxic CD8+ T-cell subpopulations of expanded and unexpanded TCRαβ clonotypes were shared in affected skin and blister fluid but absent or unexpanded in SJS/TEN unaffected skin. SJS/TEN blister fluid is a rich reservoir of oligoclonal CD8+ T-cells with an effector phenotype driving SJS/TEN pathogenesis. This multiomic database will act as the basis to define antigen-reactivity, HLA restriction, and signatures of drug-antigen-reactive T-cell clonotypes at a tissue level.

Multiomic single-cell sequencing defines tissue-specific responses in Stevens-Johnson Syndrome and Toxic epidermal necrolysis.

Stevens-Johnson syndrome and toxic epidermal necrolysis (SJS/TEN) is a rare but life-threatening cutaneous drug reaction mediated by human leukocyte antigen (HLA) class I-restricted CD8 T cells. For unbiased assessment of cellular immunopathogenesis, here we perform single-cell (sc) transcriptome, surface proteome, and T cell receptor (TCR) sequencing on unaffected skin, affected skin, and blister fluid from 15 SJS/TEN patients. From 109,888 cells, we identify 15 scRNA-defined subsets. Keratinocytes express markers indicating HLA class I-restricted antigen presentation and appear to trigger the proliferation of and killing by cytotoxic CD8 tissue-resident T cells that express granulysin, granzyme B, perforin, LAG3, CD27, and LINC01871, and signal through the PKM, MIF, TGFβ, and JAK-STAT pathways. In affected tissue, cytotoxic CD8 T cells express private expanded and unexpanded TCRαβ that are absent or unexpanded in unaffected skin, and mixed populations of macrophages and fibroblasts express pro-inflammatory markers or those favoring repair. This data identifies putative cytotoxic TCRs and therapeutic targets.

Article	Year
Differential Effects of Glutamine Inhibition Strategies on Antitumor CD8 T Cells. Journal of immunology (Baltimore, Md. : 1950)\| PubMed ID: 37341499	2023
Efficient T cell adoptive transfer in lymphoreplete hosts mediated by transient activation of Stat5 signaling. Molecular therapy : the journal of the American Society of Gene Therapy\| PubMed ID: 37481703	2023
Transposon-Based Manufacturing of Human CAR-T Cells. Methods in molecular biology (Clifton, N.J.)\| PubMed ID: 38070116	2024
Multiomic single-cell sequencing defines tissue-specific responses in Stevens-Johnson Syndrome and Toxic epidermal necrolysis. bioRxiv : the preprint server for biology\| PubMed ID: 38405793	2024
Multiomic single-cell sequencing defines tissue-specific responses in Stevens-Johnson syndrome and toxic epidermal necrolysis. Nature communications\| PubMed ID: 39379371	2024

Richard O'Neil

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