Dysregulation of anergy‐related factors involved in regulatory T cells defects in Systemic Lupus Erythematosus patients: Rapamycin and Vitamin D efficacy in restoring regulatory T cells

• Published in: International journal of rheumatic diseases 2016-12, Vol.19 (12), p.1294-1303
• Main Authors: Banica, Leontina M., Besliu, Alina N., Pistol, Gina C., Stavaru, Crina, Vlad, Violeta, Predeteanu, Denisa, Ionescu, Ruxandra, Stefanescu, Maria, Matache, Cristiana
• Format: Article
• Language: English
• Subjects: Adaptor Proteins, Signal Transducing - blood; Adaptor Proteins, Signal Transducing - genetics; anergy‐related factors; Calcitriol - pharmacology; Case-Control Studies; Cell Proliferation - drug effects; Cells, Cultured; Clonal Anergy - drug effects; Early Growth Response Protein 2 - blood; Early Growth Response Protein 2 - genetics; Early Growth Response Protein 3 - blood; Early Growth Response Protein 3 - genetics; Humans; Immunologic Factors - pharmacology; Lupus Erythematosus, Systemic - blood; Lupus Erythematosus, Systemic - drug therapy; Lupus Erythematosus, Systemic - immunology; Lymphocyte Activation - drug effects; Phenotype; Proto-Oncogene Proteins c-cbl - blood; Proto-Oncogene Proteins c-cbl - genetics; rapamycin; regulatory T cells; RNA, Messenger - blood; RNA, Messenger - genetics; Self Tolerance - drug effects; Sirolimus - pharmacology; systemic lupus erythematosus; T-Lymphocytes, Regulatory - drug effects; T-Lymphocytes, Regulatory - immunology; T-Lymphocytes, Regulatory - metabolism; Time Factors; Ubiquitin-Protein Ligases - blood; Ubiquitin-Protein Ligases - genetics; vitamin D
• ISSN: 1756-1841; 1756-185X
• DOI: 10.1111/1756-185X.12509

Aim Systemic Lupus Erythematosus (SLE) patients display dysfunctions in T cell activation and anergy. Therefore the aims of our study were to explore the expression of anergy‐related factors in CD4+ T cells in relationship with regulatory T cells (Tregs) frequency in SLE patients and to identify strategies to redress these defects. Method Casitas B‐cell lymphoma b (Cbl‐b) and ‘gene related to anergy in lymphocytes' (GRAIL) proteins were analyzed in peripheral blood mononuclear cells (PBMCs) from SLE patients and healthy donors (HD) by immunoblotting. cbl‐b, grail, growth response factors (egr)2 and egr3 messenger RNAs (mRNAs) were evaluated by real‐time polymerase chain reaction in SLE and HD PBMCs and CD4+ T cells. Phenotypic and functional characterization of CD4+ T cells was performed by flow cytometry. Tregs expansion protocol consisted in culturing CD4+ T cells for 14 or 21 days of experimental activation with anti‐CD3 and anti‐CD28 monoclonal antibodies, human recombinant interleukin (hrIL)‐2, in the absence or presence of rapamycin (Rapa) or 1,25‐(OH)2D3 (vitamin D: VitD). Results SLE PBMCs expressed low levels of Cbl‐b and GRAIL proteins. Both SLE PBMCs and CD4+ T cells expressed low levels of egr2/3 mRNAs. SLE patients had a reduced number of Tregs with impaired suppressive activity. An association between egr2 mRNA level in CD4+ T cells and Tregs percentage was identified. Experimental activation of CD4+ T cells in the presence of hrIL‐2 and Rapa or VitD induced the expansion of SLE Tregs. However, on long‐term, only Rapa exposure of SLE CD4+ T cells yielded high numbers of Tregs with sustained suppressive activity. Conclusion Our results suggest a new strategy to correct defects in CD4+ T cell tolerance mechanisms that may prove beneficial in SLE.