Autophagy differentially regulates tissue tolerance of distinct target organs in graft-versus-host disease models
Katherine Oravecz-Wilson, … , Chen Liu, Pavan Reddy
Katherine Oravecz-Wilson, … , Chen Liu, Pavan Reddy
Published March 1, 2024
Citation Information: J Clin Invest. 2024;134(5):e167369. https://doi.org/10.1172/JCI167369.
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Research Article Immunology

Autophagy differentially regulates tissue tolerance of distinct target organs in graft-versus-host disease models

Abstract

Tissue-intrinsic mechanisms that regulate severity of systemic pathogenic immune-mediated diseases, such as acute graft-versus-host disease (GVHD), remain poorly understood. Following allogeneic hematopoietic stem cell transplantation, autophagy, a cellular stress protective response, is induced in host nonhematopoietic cells. To systematically address the role of autophagy in various host nonhematopoietic tissues, both specific classical target organs of acute GVHD (intestines, liver, and skin) and organs conventionally not known to be targets of GVHD (kidneys and heart), we generated mice with organ-specific knockout of autophagy related 5 (ATG5) to specifically and exclusively inhibit autophagy in the specific organs. When compared with wild-type recipients, animals that lacked ATG5 in the gastrointestinal tract or liver showed significantly greater tissue injury and mortality, while autophagy deficiency in the skin, kidneys, or heart did not affect mortality. Treatment with the systemic autophagy inducer sirolimus only partially mitigated GVHD mortality in intestine-specific autophagy-deficient hosts. Deficiency of autophagy increased MHC class I on the target intestinal epithelial cells, resulting in greater susceptibility to damage by alloreactive T cells. Thus, autophagy is a critical cell-intrinsic protective response that promotes tissue tolerance and regulates GVHD severity.

Authors

Katherine Oravecz-Wilson, Emma Lauder, Austin Taylor, Laure Maneix, Jeanine L. Van Nostrand, Yaping Sun, Lu Li, Dongchang Zhao, Chen Liu, Pavan Reddy

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Figure 5

IECs from Villin-Cre+ Atg5–/– mice show increased levels of MHC-I compared with WT cells.

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IECs from Villin-Cre+ Atg5–/– mice show increased levels of MHC-I compar...
(A) Total number of MHC-I+ IECs isolated from the small intestine of naive B6 Villin-KO mice and B6 WT littermates. Cells were stained with H2Kb antibodies and analyzed by flow cytometry. (B) Representative micrographs (original magnification, ×20) with immunohistochemical staining for MHC-I (β2M) on small intestine tissue from naive B6 Villin-KO and B6 WT mice. (C) Primary mouse hepatocytes were stained with H2Kb antibody and analyzed by flow cytometry. (D) Complete immunofluorescence panel of single-color and merged images from PCEC lines treated with LPS or hydroxychloroquine (CQ). Representative micrographs (original magnification, ×20) were stained with antibodies for MHC-I (β2M) and LC3 (LC3A/B) and analyzed via confocal microscopy. Perinuclear yellow colocalization (white arrows) can be observed, as well as accumulation of green cytoplasmic autophagosomes (magenta arrows) in CQ-treated cells. (E) Lysates from PCEC lines treated with LPS or CQ and control-treated cells were subjected to immunoprecipitation (IP) with MHC-I (β2M) antibody and analyzed by Western blot with LC3A/B antibody. (F) Lysates from untreated primary mouse hepatocytes were subjected to IP with MHC-I (β2M) antibody and analyzed by Western blot with LC3B antibody. (G) Primary mouse hepatocytes from B6 WT or B6 Albumin-KO mice were cocultured with activated BALB/c T cells, and cell death was measured after 4 hours. A represents data from naive mice (B6 WT, n = 6; B6 Villin-KO, n = 6). C represents data from naive mice (B6 WT, n = 5; B6 Albumin-KO, n = 3). E and F represent analysis from 1 experimental run. G represents analysis from 1 experimental run. Significance was determined using unpaired t test. *P < 0.05, ***P < 0.001.