Browsing by Author "Oravecz-Wilson, Katherine"

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    ATG5-Dependent Autophagy Uncouples T-cell Proliferative and Effector Functions and Separates Graft-versus-Host Disease from Graft-versus-Leukemia
    (American Association for Cancer Research, 2021) Oravecz-Wilson, Katherine; Rossi, Corinne; Zajac, Cynthia; Sun, Yaping; Li, Lu; Decoville, Thomas; Fujiwara, Hideaki; Kim, Stephanie; Peltier, Daniel; Reddy, Pavan; Medicine, School of Medicine
    Autophagy is a vital cellular process whose role in T immune cells is poorly understood, specifically, in its regulation of allo-immunity. Stimulation of wild-type T cells in vitro and in vivo with allo-antigens enhances autophagy. To assess the relevance of autophagy to T-cell allo-immunity, we generated T-cell-specific Atg5 knock-out mice. Deficiency of ATG5-dependent autophagy reduced T-cell proliferation and increased apoptosis following in vitro and in vivo allo-stimulation. The absence of ATG5 in allo-stimulated T cells enhanced their ability to release effector cytokines and cytotoxic functions, uncoupling their proliferation and effector functions. Absence of autophagy reduced intracellular degradation of cytotoxic enzymes such as granzyme B, thus enhancing the cytotoxicity of T cells. In several in vivo models of allo-HSCT, ATG5-dependent dissociation of T-cell functions contributed to significant reduction in graft-versus-host disease (GVHD) but retained sufficient graft versus tumor (GVT) response. Our findings demonstrate that ATG5-dependent autophagy uncouples T-cell proliferation from its effector functions and offers a potential new strategy to enhance outcomes after allo-HSCT. SIGNIFICANCE: These findings demonstrate that induction of autophagy in donor T-cell promotes GVHD, while inhibition of T-cell autophagy mitigates GVHD without substantial loss of GVL responses.
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    Mitochondrial Complex II In Intestinal Epithelial Cells Regulates T-cell Mediated Immunopathology
    (Springer Nature, 2021) Fujiwara, Hideaki; Seike, Keisuke; Brooks, Michael D.; Mathew, Anna V.; Kovalenko, Ilya; Pal, Anupama; Lee, Ho-Joon; Peltier, Daniel; Kim, Stephanie; Liu, Chen; Oravecz-Wilson, Katherine; Li, Lu; Sun, Yaping; Byun, Jaeman; Maeda, Yoshinobu; Wicha, Max S.; Saunders, Tom; Rehemtulla, Alnawaz; Lyssiotis, Costas A.; Pennathur, Subramaniam; Reddy, Pavan; Microbiology and Immunology, School of Medicine
    Intestinal epithelial cell (IEC) damage by T cells contributes to graft-versus-host disease (GVHD), inflammatory bowel disease (IBD) and immune checkpoint blockade (ICB) mediated colitis. But little is known about the target cell intrinsic features that influence disease severity. Herein we identified disruption of oxidative phosphorylation and an increase in succinate levels in the IECs from several distinct in vivo models of T cell mediated colitis. Metabolic flux studies, complemented by imaging and protein analyses identified disruption of IEC intrinsic succinate dehydrogenase A (SDHA), a component of mitochondrial complex II, in causing these metabolic alterations. The relevance of IEC intrinsic SDHA in mediating disease severity was confirmed by complementary chemical and genetic experimental approaches and validated in human clinical samples. These data identify a critical role for the alteration of the IEC specific mitochondrial complex II component SDHA in the regulation of the severity of T cell mediated intestinal diseases.
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    Rearrangement of T Cell genome architecture regulates GVHD
    (Elsevier, 2022-08-06) Sun, Yaping; Dotson, Gabrielle A.; Muir, Lindsey A.; Ronquist, Scott; Oravecz-Wilson, Katherine; Peltier, Daniel; Seike, Keisuke; Li, Lu; Meixner, Walter; Rajapakse, Indika; Reddy, Pavan; Pediatrics, School of Medicine
    WAPL, cohesin's DNA release factor, regulates three-dimensional (3D) chromatin architecture. The 3D chromatin structure and its relevance to mature T cell functions is not well understood. We show that in vivo lymphopenic expansion, and alloantigen-driven proliferation, alters the 3D structure and function of the genome in mature T cells. Conditional deletion of WAPL, cohesin's DNA release factor, in T cells reduced long-range genomic interactions and altered chromatin A/B compartments and interactions within topologically associating domains (TADs) of the chromatin in T cells at baseline. WAPL deficiency in T cells reduced loop extensions, changed expression of cell cycling genes and reduced proliferation following in vitro and in vivo stimulation, and reduced severity of graft-versus-host disease (GVHD) following experimental allogeneic hematopoietic stem cell transplantation. These data collectively characterize 3D genomic architecture of T cells in vivo and demonstrate biological and clinical implications for its disruption by cohesin release factor WAPL.
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    RNA-seq of Human T Cells after Hematopoietic Stem Cell Transplantation Identifies Linc00402 as a Regulator of T-Cell Alloimmunity
    (American Association for the Advancement of Science, 2021) Peltier, Daniel; Radosevich, Molly; Ravikumar, Visweswaran; Pitchiaya, Sethuramasundaram; Decoville, Thomas; Wood, Sherri C.; Hou, Guoqing; Zajac, Cynthia; Oravecz-Wilson, Katherine; Sokol, David; Henig, Israel; Wu, Julia; Kim, Stephanie; Taylor, Austin; Fujiwara, Hideaki; Sun, Yaping; Rao, Arvind; Chinnaiyan, Arul M.; Goldstein, Daniel R.; Reddy, Pavan; Pediatrics, School of Medicine
    Mechanisms governing allogeneic T cell responses after solid organ and allogeneic hematopoietic stem cell transplantation (HSCT) are incompletely understood. To identify lncRNAs that regulate human donor T cells after clinical HSCT, we performed RNA sequencing on T cells from healthy individuals and donor T cells from three different groups of HSCT recipients that differed in their degree of major histocompatibility complex (MHC) mismatch. We found that lncRNA differential expression was greatest in T cells after MHC-mismatched HSCT relative to T cells after either MHC-matched or autologous HSCT. Differential expression was validated in an independent patient cohort and in mixed lymphocyte reactions using ex vivo healthy human T cells. We identified Linc00402, an uncharacterized lncRNA, among the lncRNAs differentially expressed between the mismatched unrelated and matched unrelated donor T cells. We found that Linc00402 was conserved and exhibited an 88-fold increase in human T cells relative to all other samples in the FANTOM5 database. Linc00402 was also increased in donor T cells from patients who underwent allogeneic cardiac transplantation and in murine T cells. Linc00402 was reduced in patients who subsequently developed acute graft-versus-host disease. Linc00402 enhanced the activity of ERK1 and ERK2, increased FOS nuclear accumulation, and augmented expression of interleukin-2 and Egr-1 after T cell receptor engagement. Functionally, Linc00402 augmented the T cell proliferative response to an allogeneic stimulus but not to a nominal ovalbumin peptide antigen or polyclonal anti-CD3/CD28 stimulus. Thus, our studies identified Linc00402 as a regulator of allogeneic T cell function.