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 Transplantation

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 1

Villin-Cre+ Atg5–/– mice display increased mortality and a greater severity of GVHD after allo-BMT in the absence of autophagy in the gut.

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Villin-Cre+ Atg5–/– mice display increased mortality and a greater sever...
(A) Schematic of CAG-RFP-EGFP-LC3 mice with dual fluorescent expression capabilities, which distinguishes autophagosomes from autolysosomes. (B) Induction of autophagy on day 3 after BMT in small intestine from CAG-RFP-EGFP-LC3 recipients (original magnification, ×20). (C–F) B6 Villin-Cre+ Atg5–/– mice (B6 Villin-KO) and Villin-Cre– Atg5fl/fl wild-type (B6 WT) littermate controls on a C57BL/6 background were used as recipients for syngeneic (syn) and MHC-mismatched allo-BMT. Mice were monitored weekly for survival (C), weight change (D), and GVHD score (E). (F) GVHD score in the small intestine on day 7 after BMT with representative micrographs (original magnification, ×20) of H&E-stained sections. (G) Phenotype of intestinal donor (H2Kd+) CD3+ T cells at day 4 after BMT. (H) Concentration of serum cytokines on day 7 after BMT in B6 Villin-KO and B6 WT mice, measured by ELISA. (I) B6 WT and B6 Villin-KO mice received either syn- or allo-BMT; these 2 groups were split in two and treated with either sirolimus (rapa) or control (con). Survival curves after BMT. (J) B6 WT mice received either syn- or allo-BMT; these 2 groups were split in two and treated with either sirolimus (rapa) or control (con). Survival curves after BMT. C–E represent 2 independent experiments (Syn, n = 7; Allo B6 WT, n = 14; Allo KO, n = 14). F and H represent analysis on day 7 after BMT (F: B6 WT, n = 7; B6 Villin-KO, n = 4; H: B6 WT, n = 5; B6 Villin-KO, n = 7). G represents analysis on day 4 after BMT (B6 WT, n = 4; B6 Villin-KO, n = 4). I represents 2 independent experiments (syn, n = 4; Allo B6 WT con, n = 5; rapa, n = 10; B6 Villin KO con, n = 10; rapa, n = 7) for 50 days. J represents 2 independent experiments (syn B6 con, n = 3; syn B6 rapa, n = 3; allo B6 con, n = 10; allo B6 rapa, n = 10) for 50 days. Significance was determined using log-rank (Mantel-Cox) test for survival curves and unpaired t test for weight and GVHD score. *P < 0.05, **P < 0.01, ****P < 0.0001.