Mitochondria, cell death, and B cell tolerance.
To prevent autoimmunity, it is critical that tolerance mechanisms block autoantibody production from self-reactive B cells. B cell tolerance is maintained through mechanisms that can reversibly or irreversibly silence autoreactive B cells. Of these mechanisms, those that lead to B cell death offer the most reliable form of tolerance to prevent autoimmunity. In many cases, death of autoreactive B cells is regulated by the cell intrinsic, or mitochondrial pathway of cell death. The pro-apoptotic Bcl-2 family proteins, Bak, Bax, and Bim have been shown to be required for disruption of mitochondria and intrinsic cell death of self-reactive B cells whereas the anti-apoptotic Bcl-2, Bcl-xL, and Mcl-1 can prevent cell death by interfering with the action of Bax and Bak. Bcl-2 and Bcl-xL have also been shown to regulate the autophagic cell death pathway that may also play a role in B cell tolerance. Even after mitochondrial disruption, mechanisms exist that may impede activation of caspases and death of autoreactive B cells. Together, understanding of cell death mechanisms and how they may affect B cell tolerance has made significant recent advances and it is now important to incorporate alternate and post-mitochondrial cell death mechanisms into B cell tolerance models.
Deming
Paula B
PB
Department of Pathology and Vermont Cancer Center, University of Vermont, Burlington, Vt., USA.
Rathmell
Jeffrey C
JC
D000818:Animals; D017209:Apoptosis; D001323:Autoantibodies / Q000096:biosynthesis; D001402:B-Lymphocytes / Q000276:immunology*; D017868:Cyclic AMP-Dependent Protein Kinases / Q000502:physiology; D045304:Cytochromes c / Q000378:metabolism; D006801:Humans; D007108:Immune Tolerance; D008928:Mitochondria / Q000502:physiology*; D019253:Proto-Oncogene Proteins c-bcl-2 / Q000502:physiology; D051636:X-Linked Inhibitor of Apoptosis Protein / Q000502:physiology; D050998:bcl-2 Homologous Antagonist-Killer Protein / Q000502:physiology; D051028:bcl-2-Associated X Protein / Q000502:physiology
D001323:Autoantibodies; D019253:Proto-Oncogene Proteins c-bcl-2; D051636:X-Linked Inhibitor of Apoptosis Protein; C496866:XIAP protein, human; D050998:bcl-2 Homologous Antagonist-Killer Protein; D051028:bcl-2-Associated X Protein; D045304:Cytochromes c; D017868:Cyclic AMP-Dependent Protein Kinases