Cytosolic HMGB1 controls the cellular autophagy/apoptosis checkpoint during inflammation

Xiaorong Zhu, Jeannette S. Messer, Yunwei Wang, Fanfei Lin, Candace M. Cham, Jonathan Chang, Timothy R. Billiar, Michael T. Lotze, David L. Boone, Eugene B. Chang*

*Corresponding author for this work

Research output: Contribution to journalArticlepeer-review

154 Scopus citations

Abstract

The intracellular protein HMGB1 is released from cells and acts as a damage-associated molecular pattern molecule during many diseases, including inflammatory bowel disease (IBD); however, the intracellular function of HMGB1 during inflammation is poorly understood. Here, we demonstrated that cytosolic HMGB1 regulates apoptosis by protecting the autophagy proteins beclin 1 and ATG5 from calpain-mediated cleavage during inflammation. Colitis in mice with an intestinal epithelial cell'specific Hmgb1 deletion and patients with IBD were both characterized by increased calpain activation, beclin 1 and ATG5 cleavage, and intestinal epithelial cell (IEC) death compared with controls. In vitro cleavage assays and studies of enteroids verified that HMGB1 protects beclin 1 and ATG5 from calpain-mediated cleavage events that generate proapoptotic protein fragments. Together, our results indicate that HMGB1 is essential for mitigating the extent and severity of inflammation-associated cellular injury by controlling the switch between the proautophagic and proapoptotic functions of beclin 1 and ATG5 during inflammation. Moreover, these studies demonstrate that HMGB1 is pivotal for reducing tissue injury in IBD and other complex inflammatory disorders.

Original languageEnglish
Pages (from-to)1098-1110
Number of pages13
JournalJournal of Clinical Investigation
Volume125
Issue number3
DOIs
StatePublished - 2 Mar 2015
Externally publishedYes

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