HMGB1: a signal of necrosis.
When tissues are damaged, they usually heal. The cellular responses towards healing require the prior recognition that damage has occurred. High Mobility Group Box 1 protein (HMGB1) is a ubiquitous nuclear protein that is passively released by cells that have died in a traumatic, non-programmed way (necrosis). Several receptors for HMGB1 exist, and upon binding HMGB1 they alert leukocytes to extravasate from the blood into the affected tissue, trigger adaptive immunity and promote the migration and proliferation of cells (including stem cells) to repair the damaged tissue. Significantly, apoptotic cells modify their chromatin so as to bind HMGB1, which is not released. Several cell types (in particular inflammatory cells) when distressed have the ability to secrete HMGB1 actively, via a dedicated pathway, and thus produce a damage signal without dying. Because of its powerful activities, HMGB1 is involved in several disorders, including autoimmune ones.
Raucci
Angela
A
San Raffaele Scientific Institute, Milan, Italy.
Palumbo
Roberta
R
Bianchi
Marco E
ME
D000818:Animals; D001327:Autoimmune Diseases / Q000276:immunology* / Q000473:pathology; D002465:Cell Movement / Q000276:immunology; D049109:Cell Proliferation; D024243:HMGB1 Protein / Q000276:immunology*; D006801:Humans; D007962:Leukocytes / Q000276:immunology* / Q000473:pathology; D009336:Necrosis / Q000276:immunology* / Q000473:pathology; D012038:Regeneration / Q000276:immunology*; D015398:Signal Transduction / Q000276:immunology*; D013234:Stem Cells / Q000276:immunology / Q000473:pathology
D024243:HMGB1 Protein