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SIRP'alpha' SHP1 gene expression in peripheral blood monocytes and U937 myelomonocytic cells and its role in autoimmune hemolytic anemia

A C Almeida M L Barjas-Castro; S T Saad; J Rehder; Antonio Condino-Neto; Meeting of the Brazilian Society for Immunology (31. 2006 Búzios)

Abstracts São Paulo, SP: Brazilian Society for Immunology, 2006

São Paulo 2006

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  • Título:
    SIRP'alpha' SHP1 gene expression in peripheral blood monocytes and U937 myelomonocytic cells and its role in autoimmune hemolytic anemia
  • Autor: A C Almeida
  • M L Barjas-Castro; S T Saad; J Rehder; Antonio Condino-Neto; Meeting of the Brazilian Society for Immunology (31. 2006 Búzios)
  • Assuntos: IMUNOLOGIA
  • É parte de: Abstracts São Paulo, SP: Brazilian Society for Immunology, 2006
  • Notas: Disponível em CD-ROM
  • Descrição: Introduction and Objectives: The interaction between macrophage SIRP and erythrocyte CD47 results in SHP1 recruitment, leading to inhibition of phagocytosis. In Autoimmune Hemolytic Anemia (AIHA), erythrocytes are coated with auto-antibody and cleared. We consider that a failure in phagocytosis inhibition could contribute to the disease. Our objective was to investigate the expression of SIRP and SHP1 in AIHA patients' peripheral blood monocytes (PBM), and the effects of IFNã/TNF (IT) and dexamethasone (DX - first choice treatment) on their expression in healthy PBM and U937 cells. Methods: SIRP and SHP1 gene expression from AIHA PBM (n=6), U937 cells (n=6) and healthy PBM (n=5) cultured during 72h with IT and/or DX was determined by Real Time PCR. Results: PBM: AIHA express more SIRP (Mean ± SD, 15,88 ± 5,43) and SHP1 (12,99 ± 3,85) than healthy PBM cultured in basal conditions (control; SIRPa 6,25 ± 5,72; SHP1 6,42 ± 4,10); Compared to control PBM, DX increases SIRP (24,87 ± 12,02) and SHP1 (19,12 ± 6,23) gene expression; IT alone do not increase significantly SIRP (14,94 ± 9,03) or SHP1 (12,31 ± 7,13) gene expression, but when associated with DX, it potentiates DX effect over both gene expression (SIRP 58,26 ± 37,79; SHP1 27,12 ± 18,44). U937 cells: Compared to control cells (1,58 ± 0,50), IT and/or DX treatment increases SHP1 gene expression (DX 4,71 ± 1,96; IT 12,67 ± 7,16; DXIT 8,17 ± 4,70), while SIRP gene expression (control 1,97 ±
    1,41) increases after IT (6,10 ± 3,62) or DXIT (3,74 ± 1,22) treatment, but not with DX alone (4,87 ± 4,71); All U937 cells treatments show smaller SIRP gene expression than AIHA, but SHP1 gene expression is the same as AIHA after IT or DXIT treatment. SIRP and SHP1 gene expression are bigger in PBM than in U937 cells, except after IT treatment. Conclusion: Increased SIRP and SHP1 gene expression in AIHA can be a homeostatic mechanism to increased erythrophagocytosis. DX increases SIRP and SHP1 gene expression in PBM, a possible mode of action for the reduction of erythrophagocytosis. SIRP and SHP1 gene expression increases during myelomonocytic cell maturation process, and after maturation they become more susceptible to DX stimuli.
  • Editor: São Paulo
  • Data de criação/publicação: 2006
  • Formato: res. MI.002.
  • Idioma: Inglês
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  • Realização: ABCD-USP USP   Logos de Redes Sociais: Freepik

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