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Mice lacking the p53-effector gene Gadd45a develop a lupus-like syndrome
Jesus M Salvador1, M Christine Hollander, Anh Thu Nguyen
1Gene Response Section, Center for Cancer Research, National Cancer Institute, Bethesda, MD 20892, USA.
Abstract:
This study addresses the biological function of the p53-effector genes Gadd45a and p21 in the immune system. We find that Gadd45a is a negative regulator of T cell proliferation because, compared to wild-type cells, Gadd45a(-/-) T cells have a lower threshold of activation and proliferate to a greater extent following primary T cell receptor stimulation. Gadd45a(-/-) mice develop an autoimmune disease, similar to human systemic lupus erythematosus (SLE), characterized by high titers of anti-dsDNA, anti-ssDNA, and anti-histone autoantibodies, severe hematological disorders, autoimmune glomerulonephritis, and premature death. Here we show that the lack of both Gadd45a and p21 dramatically accelerates the development of autoimmunity observed in each individual single-gene disruption mutant, demonstrating that these genes play nonredundant roles in the immune response.
Insights
Growth arrest and DNA damage-inducible (Gadd45a) and cyclin-dependent kinase inhibitor 1 (p21) genes regulate T cell proliferation and prevent autoimmune disease. Their absence accelerates autoimmunity, highlighting their distinct immune functions.
Area of Science:
- Immunology
- Molecular Biology
- Genetics
Background:
- The p53-inducible genes Gadd45a and p21 are critical regulators of cellular processes.
- Their specific roles in immune system regulation and autoimmunity remain incompletely understood.
Purpose of the Study:
- To investigate the biological functions of Gadd45a and p21 within the immune system.
- To determine their involvement in T cell proliferation and the development of autoimmune diseases.
Main Methods:
- Utilized gene-knockout mouse models (Gadd45a(-/-) and p21(-/-)) to study immune responses.
- Analyzed T cell activation thresholds and proliferation following T cell receptor stimulation.
- Assessed autoimmune disease development, including autoantibody production and organ pathology.
Main Results:
- Gadd45a acts as a negative regulator of T cell proliferation, with Gadd45a(-/-) T cells exhibiting increased activation and proliferation.
- Gadd45a(-/-) mice develop a lupus-like autoimmune disease characterized by autoantibodies, hematological disorders, and glomerulonephritis.
- The combined absence of Gadd45a and p21 significantly accelerates autoimmune disease onset compared to single-gene disruptions, indicating nonredundant roles.
Conclusions:
- Gadd45a and p21 play crucial, nonredundant roles in maintaining immune homeostasis.
- These genes are essential for preventing the development of systemic autoimmunity.
- Dysregulation of Gadd45a and p21 contributes to autoimmune pathogenesis, offering potential therapeutic targets.