Dataset Information

Acquired deficiency of A20 results in rapid apoptosis, systemic inflammation, and abnormal hematopoietic stem cell function.

ABSTRACT: A20 is a negative regulator of NF-?B, and mutational loss of A20 expression is involved in the pathogenesis of autoimmune diseases and B-cell lymphomas. To clarify the role of A20 in adult hematopoiesis, we generated conditional A20 knockout mice (A20(flox/flox) ) and crossed them with Mx-1Cre (MxCre (+)) and ERT2Cre (ERT2Cre (+)) transgenic mice in which Cre is inducibly activated by endogenous interferon and exogenous tamoxifen, respectively. A20(flox/flox) MxCre (+) (A20Mx) mice spontaneously exhibited myeloid proliferation, B cell apoptosis, and anemia with overproduction of pro-inflammatory cytokines. Bone marrow transplantation demonstrated that these changes were caused by hematopoietic cells. NF-?B was constitutively activated in A20Mx hematopoietic stem cells (HSCs), which caused enhanced cell cycle entry and impaired repopulating ability. Tamoxifen stimulation of A20(flox/flox) ERT2Cre (+) (A20ERT2) mice induced fulminant apoptosis and subsequent myeloproliferation, lymphocytopenia, and progressive anemia with excessive production of pro-inflammatory cytokines, as observed in A20Mx mice. These results demonstrate that A20 plays essential roles in the homeostasis of adult hematopoiesis by preventing apoptosis and inflammation. Our findings provide insights into the mechanism underlying A20 dysfunction and human diseases in which A20 expression is impaired.

SUBMITTER: Nagamachi A

PROVIDER: S-EPMC3909109 | biostudies-literature | 2014

REPOSITORIES: biostudies-literature

ACCESS DATA

Publications

Acquired deficiency of A20 results in rapid apoptosis, systemic inflammation, and abnormal hematopoietic stem cell function.

Nagamachi Akiko A Nakata Yuichiro Y Ueda Takeshi T Yamasaki Norimasa N Ebihara Yasuhiro Y Tsuji Kohichiro K Honda Zen-ichiro Z Takubo Keiyo K Suda Toshio T Oda Hideaki H Inaba Toshiya T Honda Hiroaki H

PloS one 20140131 1

A20 is a negative regulator of NF-κB, and mutational loss of A20 expression is involved in the pathogenesis of autoimmune diseases and B-cell lymphomas. To clarify the role of A20 in adult hematopoiesis, we generated conditional A20 knockout mice (A20(flox/flox) ) and crossed them with Mx-1Cre (MxCre (+)) and ERT2Cre (ERT2Cre (+)) transgenic mice in which Cre is inducibly activated by endogenous interferon and exogenous tamoxifen, respectively. A20(flox/flox) MxCre (+) (A20Mx) mice spontaneously ...[more]

PMID: 24498102

Similar Datasets

Project description:BackgroundA20 (TNFAIP3) is a pleiotropic NFκB-dependent gene that terminates NFκB activation in response to inflammatory stimuli. The potent anti-inflammatory properties of A20 are well characterized in several organs. However, little is known about its role in the brain. In this study, we investigated the brain phenotype of A20 heterozygous (HT) and knockout (KO) mice.MethodsThe inflammatory status of A20 wild type (WT), HT and KO brain was determined by immunostaining, quantitative PCR, and Western blot analysis. Cytokines secretion was evaluated by ELISA. Quantitative results were statistically analyzed by ANOVA followed by a post-hoc test.ResultsTotal loss of A20 caused remarkable reactive microgliosis and astrogliosis, as determined by F4/80 and GFAP immunostaining. Glial activation correlated with significantly higher mRNA and protein levels of the pro-inflammatory molecules TNF, IL-6, and MCP-1 in cerebral cortex and hippocampus of A20 KO, as compared to WT. Basal and TNF/LPS-induced cytokine production was significantly higher in A20 deficient mouse primary astrocytes and in a mouse microglia cell line. Brain endothelium of A20 KO mice demonstrated baseline activation as shown by increased vascular immunostaining for ICAM-1 and VCAM-1, and mRNA levels of E-selectin. In addition, total loss of A20 increased basal brain oxidative/nitrosative stress, as indicated by higher iNOS and NADPH oxidase subunit gp91phox levels, correlating with increased protein nitration, gauged by nitrotyrosine immunostaining. Notably, we also observed lower neurofilaments immunostaining in A20 KO brains, suggesting higher susceptibility to axonal injury. Importantly, A20 HT brains showed an intermediate phenotype, exhibiting considerable, albeit not statistically significant, increase in markers of basal inflammation when compared to WT.ConclusionsThis is the first characterization of spontaneous neuroinflammation caused by total or partial loss of A20, suggesting its key role in maintenance of nervous tissue homeostasis, particularly control of inflammation. Remarkably, mere partial loss of A20 was sufficient to cause chronic, spontaneous low-grade cerebral inflammation, which could sensitize these animals to neurodegenerative diseases. These findings carry strong clinical relevance in that they question implication of identified A20 SNPs that lower A20 expression/function (phenocopying A20 HT mice) in the pathophysiology of neuroinflammatory diseases.

Dataset Information

Acquired deficiency of A20 results in rapid apoptosis, systemic inflammation, and abnormal hematopoietic stem cell function.

Publications

Acquired deficiency of A20 results in rapid apoptosis, systemic inflammation, and abnormal hematopoietic stem cell function.

Similar Datasets

OmicsDI is part of the ELIXIR infrastructure

Tweets