Novel Role of p53 in Septic Immunosuppression: Involvement in Loss and Dysfunction of CD4+ T Lymphocytes

Abstract

Background/Aims: Immunosuppression frequently occurs during the development of sepsis and is closely associated with poor outcome. Characteristics of immunosuppressive CD4⁺ T lymphocytes in sepsis have been reported to include dramatic cell loss and inactivation. p53 acts as a pivotal transcription factor in regulating cell proliferation and apoptosis, which control tumorigenesis. However, few studies have investigated the universal role of p53 in immune cells, especially in the development of sepsis. Methods: A mouse model of sepsis was produced by cecal ligation and puncture (CLP), and isolated splenic CD4⁺ T cells or Jurkat cells were exposed to lipopolysaccharide (LPS) stimulation in vitro. We used genetic knockout (p53^-/-) mice or the specific inhibitor pifithrin-α (PFT) to investigate the regulatory mechanisms of p53. Cell proliferation ability was assessed using a Cell Counting Kit-8 assay, and apoptotic cells were stained with annexin V/propidium iodide and then analyzed using a FACScan flow cytometer. Protein and mRNA expression levels were measured by western blotting and real-time PCR, and cytokine levels in culture supernatants were determined by enzyme-linked immunosorbent assay. Results: Splenic CD4⁺ T lymphocytes from CLP mice expressed gradually elevated p53 mRNA and protein levels, which resulted in extracellular regulated protein kinase 1/2 inactivation and expression of apoptotic molecules. Specific inhibition of p53 by PFT or genetic knockout (p53^-/-) maintained CD4⁺ T lymphocyte homeostasis, as indicated by protection from cell loss and restoration of immune function. A medium dose of PFT improved the survival rate of mice, while mortality rate showed only a slight improvement in p53^-/- mice compared with wild-type mice. The in vitro responses to LPS were consistent with these results, and upregulation of p53 clearly affected the proliferation, apoptosis, and immune dysfunction of CD4⁺ T lymphocytes. In addition, we confirmed the regulatory effect of p53 in Jurkat cells, and inhibition of p53 by either inhibition or short hairpin RNA transduction markedly protected cells from LPS stimulation. Conclusion: Elevation of p53 in T lymphocytes during sepsis or endotoxin challenge might be responsible for inhibiting cell proliferation and enhancing both apoptosis and immune dysfunction of T cells.

Differential long non‑coding RNA expression profiles in the peripheral blood and CD4+ T cells of patients with active rheumatoid arthritis

“…MAPK phosphorylation results in the activation of the downstream inflammatory transcription factor NF-κB, which may control the activation of the Th17-associated cytokine IL17 and the Treg-associated cytokine TGF-β (32,33); this is consistent with the present results. P53 serves an important role in the differentiation of Treg cells and the homeostasis of CD4 + T cells (33)(34)(35). The present study suggested that lncRNAs are involved in the pathogenesis of RA, which is possibly regulated by the differentiation of CD4 + T lymphocytes.…”

Identification of Potential Biomarkers and Immune Features of Sepsis Using Bioinformatics Analysis

“…TP53 may contribute to apoptosis in a tissue-dependent manner. A recent study revealed that p53 expression in T lymphocytes during sepsis could be responsible for enhancing both apoptosis and immune dysfunction in T-cells [ 33 ]. In our microarray analyses, TP53 expression was found to be downregulated in patients with sepsis, which is in accordance with the expression of genes involved in the T-cell signaling pathway, suggesting their possible interaction during sepsis.…”

The Role of BCL2 Protein and Tumour Protein p53 in Septic Cardiomyopathy

“…Immunohistochemical analysis were performed on 4 µm thick sections using Ventana Benchmark GX (Ventana Medical Systems Inc., Tucson, AZ, USA) automated staining instrument. Following the manufacturer's instructions, the slides were deparaffinized using EZ prep solution (Ventana Medical Systems, Inc.), incubated with monoclonal antibodies, developed using the Opti View DAB detection kit (Ventana Medical Systems, Inc.) and counterstained with haematoxylin and blueing [7,[19][20][21][22][23][24][25]. For BCL2 staining, cells were incubated for 20 minutes with anti-bcl-2 monoclonal primary antibody (CONFIRM, 124, mouse, IgG1, cytoplasmic, IVD) in accordance with the manufacture protocol [35].…”

“…A murine model showed that mice with p53 expression lymphocytes had a different apoptotic response in splenocytes and thymocytes. This suggests a cell-type specific cellular response or deathinducing signal [21]. Another study suggests that an increase of p53 in T lymphocytes might be responsible for inhibiting the cell proliferation and enhancing apoptosis and immune dysfunction of T cells during sepsis or endotoxin challenge [22].…”