RESUMO
GATA-binding factor 1 (GATA1) is a transcription factor that governs the development and function of multiple hematopoietic cell lineages. GATA1 is expressed in hematopoietic stem and progenitor cells (HSPCs) and is essential for erythroid lineage commitment; however, whether it plays a role in hematopoietic stem cell (HSC) biology and the development of myeloid cells, and what that role might be, remains unclear. We initially set out to test the role of eosinophils in experimental autoimmune encephalomyelitis (EAE), a model of central nervous system autoimmunity, using mice lacking a double GATA-site (ΔdblGATA), which lacks eosinophils due to the deletion of the dblGATA enhancer to Gata1, which alters its expression. ΔdblGATA mice were resistant to EAE, but not because of a lack of eosinophils, suggesting that these mice have an additional defect. ΔdblGATA mice with EAE had fewer inflammatory myeloid cells than the control mice, suggesting that resistance to EAE is caused by a defect in myeloid cells. Naïve ΔdblGATA mice also showed reduced frequency of CD11b+ myeloid cells in the blood, indicating a defect in myeloid cell production. Examination of HSPCs revealed fewer HSCs and myeloid cell progenitors in the ΔdblGATA bone marrow (BM), and competitive BM chimera experiments showed a reduced capacity of the ΔdblGATA BM to reconstitute immune cells, suggesting that reduced numbers of ΔdblGATA HSPCs cause a functional deficit during inflammation. Taken together, our data show that GATA1 regulates the number of HSPCs and that reduced GATA1 expression due to dblGATA deletion results in a diminished immune response following the inflammatory challenge.
Assuntos
Fator de Transcrição GATA1 , Células-Tronco Hematopoéticas , Doenças Neuroinflamatórias , Animais , Camundongos , Diferenciação Celular , Regulação da Expressão Gênica , Células-Tronco Hematopoéticas/metabolismo , Fator de Transcrição GATA1/metabolismoRESUMO
Peptides are molecules that have emerged as crucial candidates for the development of anticancer drugs. Spider venoms are a rich source of peptides (venom peptides - VPs) with biological effects. VPs have been tested as adjuvants in the activation of cells of the immune system with the aim of improving immunotherapies for the treatment of neoplasms. In the present study, the effects of SNX-482, a peptide from the African tarantula Hysterocrates gigas, on macrophages were described. The results showed that the peptide activated M0-macrophages, increasing costimulatory molecules (CD40, CD68, CD80, CD83, CD86) involved in antigen presentation, and also augmenting the checkpoint molecules PD-L1, CTLA-4 and FAS-L; these effects were not concentration-dependent. SNX-482 also increased the release of IL-23 and upregulated the expression of ccr4, ifn-g, gzmb and pdcd1, genes important for the anticancer response. The pretreatment of macrophages with the peptide did not interfere in the modulation of T cells, and macrophages previously polarized to M1 and M2 profile did not respond to SNX-482. These findings represent the expansion of knowledge about the use of VPs in drug discovery, pointing to a potential new candidate for anticancer immunotherapy. Considering that most immunotherapies target the adaptive system, the modulation of macrophages (an innate immune cell) by SNX-482 is especially relevant.
Assuntos
Adjuvantes Imunológicos/farmacologia , Ativação de Macrófagos/efeitos dos fármacos , Venenos de Aranha/química , Aranhas/química , Animais , Antígenos CD/imunologia , Linhagem Celular Tumoral , Polaridade Celular , Citocinas/metabolismo , Ensaio de Imunoadsorção Enzimática , Expressão Gênica , Ativação de Macrófagos/imunologia , Camundongos , Neoplasias/genética , Neoplasias/imunologia , Venenos de Aranha/farmacologiaRESUMO
MS and EAE are T cell-driven autoimmune diseases of the CNS where IL-17-producing Th17 cells promote damage and are pathogenic. Conversely, tolerogenic DCs induce Treg cells and suppress Th17 cells. Chloroquine (CQ) suppresses EAE through the modulation of DCs by unknown mechanisms. Here, we show that STAT 1 is necessary for CQ-induced tolerogenic DCs (tolDCs) to efficiently suppress EAE. We observed that CQ induces phosphorylation of STAT1 in DCs in vivo and in vitro. Genetic blockage of STAT1 abrogated the suppressive activity of CQ-treated DCs. Opposed to its WT counterparts, CQ-treated STAT1-/- BMDCs were unable to suppress Th17 cells and increased EAE severity. Our findings show that STAT1 is a major signaling pathway in CQ-induced tolDCs and may shed light on new therapeutic avenues for the induction of tolDCs in autoimmune diseases such as MS.