Anti-apoptotic Genes are Upregulated in Tolerized CD8+ Regulatory T Cells Isolated from SLE-Prone Mice (99.41)

Abstract

Abstract Purpose: We studied the role of two different regulatory T cells (CD4+CD25+Foxp3+ Treg and TGFβ/IL10-secreting CD8+ Ts) in apoptosis pathways using a mouse model of systemic lupus erythematosus (SLE). Methods: Ten-week old female NZB/NZW F1 mice were tolerized with a synthetic peptide based on anti-dsDNA VH sequences (pCons) that delays SLE symptoms or isotonic saline and killed one week later (n=6/group). After Treg and Ts isolation from spleens, gene transcript levels from three different pathways - apoptosis, T cell tolerance, and TGFβ - were examined by real-time PCR-based gene arrays (SA Biosciences). These platforms contain primers for 84 pathway-specific genes. Results: Differences in Treg mRNA between the two groups were not apparent. In Ts, however, Bcl2, survivin, COX-2, Pak7, and IL-10 transcripts were significantly elevated more than two-fold in the pCons group. The proapoptotic gene Apaf1 was also significantly downregulated, implicating inhibition of specific caspases. Western blot confirmed altered protein regulation of these genes. Bcl-2, survivin and COX-2 are direct targets of the antiapoptotic transcription factor NF-κB, and Apaf-driven signaling pathways are involved in NF-κB regulation. Conclusions: Results from these experiments provide additional insights into Ts apoptosis in SLE and could lead to novel therapeutic options designed to alter Ts biology.