title: Increased Foxp3+ regulatory T cells in poly(ADP-Ribose) polymerase-1 deficiency.
abstract: Growing evidence is unveiling a role for poly(ADP-ribose) polymerase (PARP)-1 in the regulation of inflammatory/immune responses. In the current study, we investigated the effects of PARP-1 deficiency on regulatory T cell differentiation. Increased numbers of regulatory CD4(+)CD25(+)/Foxp3(+) T cells were found in thymus, spleen, and lymph nodes of PARP-1 knockout (KO) mice compared with wild-type (WT) controls. The increased frequency of regulatory T cells in the periphery resulted in impaired CD4 cell proliferation and IL-2 production, which could be restored by CD25(+) cell depletion. Phenotype and inhibitory functions of PARP-1 KO regulatory T cells were similar to WT cells, indicating that PARP-1 affects regulatory T cell differentiation rather than function. Purified naive CD4 cells from PARP-1 KO mice stimulated in vitro expressed forkhead box p3 mRNA at higher levels and generated a greater number of Foxp3(+) cells (inducible regulatory T [iTreg] cells) than the WT counterpart. This finding was due to a higher rate of naive CD4 cell to Foxp3(+) iTreg cell conversion rather than to higher resistance to apoptosis induction. Interestingly, PARP-1 deficiency did not affect retinoid-related orphan receptor-gammat mRNA expression and differentiation of purified naive CD4 cells to Th17 cells. PARP-1 KO iTreg cells showed features similar to WT regulatory T cells, suggesting that modulation of PARP-1 during the immune response might be used to induce greater numbers of functional regulatory T cells. In conclusion, our findings represent the first evidence that PARP-1 can affect regulatory T cell differentiation and open new perspectives on potential targets for modulating immune responses.
authors.affiliation: Section of Toxicology and Biomedicine, Italian National Agency for New Technologies, Energy and Sustainable Economic Development, Santa Maria di Galeria, 00123 Rome, Italy.
authors.forename: Francesca
authors.initials: F
authors.lastname: Nasta
authors.forename: Federica
authors.initials: F
authors.lastname: Laudisi
authors.forename: Manolo
authors.initials: M
authors.lastname: Sambucci
authors.forename: Maria M
authors.initials: MM
authors.lastname: Rosado
authors.forename: Claudio
authors.initials: C
authors.lastname: Pioli
mesh_terms: D000818:Animals; D002454:Cell Differentiation / Q000276:immunology; D002469:Cell Separation; D005434:Flow Cytometry; D051858:Forkhead Transcription Factors / Q000276:immunology*; D008198:Lymph Nodes / Q000166:cytology / Q000276:immunology; D051379:Mice; D008810:Mice, Inbred C57BL; D018345:Mice, Knockout; D000071137:Poly (ADP-Ribose) Polymerase-1; D011065:Poly(ADP-ribose) Polymerases / Q000172:deficiency / Q000235:genetics / Q000276:immunology*; D020133:Reverse Transcriptase Polymerase Chain Reaction; D013154:Spleen / Q000166:cytology / Q000276:immunology; D016176:T-Lymphocyte Subsets / Q000166:cytology / Q000276:immunology*; D050378:T-Lymphocytes, Regulatory / Q000166:cytology / Q000276:immunology*; D013950:Thymus Gland / Q000166:cytology / Q000276:immunology
chemical_list: D051858:Forkhead Transcription Factors; C498833:Foxp3 protein, mouse; C499321:Parp1 protein, mouse; D000071137:Poly (ADP-Ribose) Polymerase-1; D011065:Poly(ADP-ribose) Polymerases