61ª Reunião Anual da SBPC

C. Ciências Biológicas - 9. Imunologia - 2. Imunologia Celular

THE INTRACELLULAR PATTERN RECOGNITION RECEPTOR NOD-2 IS INVOLVED IN THE PROCESS OF THE INFLAMMATORY RESPONSE IN ARTHRITIS

Silvio Manfredo Vieira 1, 2 Henrique Paula Lemos 2 Larissa Garcia Pinto 2 Thiago Mattar Cunha 2 Dario Simões Zamboni 2 Fernando Queiroz Cunha 2

1. Instituto Nacional de Pesquisas da Amazônia - INPA 2. Faculdade de Medicina de Ribeirão Preto - FMRP, Universidade de São Paulo - USP

INTRODUÇÃO:

NOD2 (nucleotide-binding oligomerization domain containing 2) is a protein, also known as the caspase recruitment domain family, member 15 (CARD15), which plays an important role in the immune system. The NOD-like receptors sense pathogens, products of damaged cells or endogenous metabolites and could potentially be involved in the initiation, amplification and progression of the inflammatory response in rheumatic diseases. Our data suggest NOD2´s crucial role in the pathogenesis of autoimmune diseases such as rheumatoid arthritis (RA).

METODOLOGIA:

Adult C57BL/6 (WT), NOD1-/-, NOD2-/-, caspase-1-/- and RIPK2-/-mice weighing 18-23 g were used. Arthritis was induced in mice with methylated bovine serum albumin (mBSA) and complete Freud's adjuvant through subcutaneous (s.c.) injection. Twenty-one days after the initial injection, arthritis was induced in the immunized animals by intra-articular (i.a.) injection of mBSA dissolved in PBS. Migration assays and histological analysis were used to evaluate neutrophil recruitment to knee joints and cartilage loss. Proteoglycan content of cartilage was measured by dimethylmethylene blue assay of papain digests. T cells and antigen-presenting cells from lymph nodes of arthritic mice were cultured in the presence of MDP or mBSA. Cytokine and chemokine levels were assessed by ELISA. Synovial and peripheral blood mononuclear cells from RA patients were also taken for RT-PCR or stimulated with MDP for ELISA and western blot assays.

RESULTADOS:

mBSA-induced arthritis, neutrophil migration and cartilage loss were completely abrogated in NOD2-/- and markedly reduced in RIPK2-/- and caspase-1-/-  mice in comparison with WT or NOD1-/-  mice. mBSA-induced i.a. production of IL-17, IL-23, IL-1b and CXCL1 was significantly reduced in NOD2-/-, caspase-1-/-  and RIPK2-/-  mice. MDP and mBSA induced IL-17, IL-23 and IL-1b production by WT lymph node cells but production of these cytokines was significantly reduced in NOD2-/-, caspase-1-/-  or RIPK2-/-  cell cultures. MDP induced in vitro IL-17, IL-23, IL-1b and CXCL8 synthesis by mononuclear cells of RA patients, but not by mononuclear cells of healthy donors (HD). RT-PCR analysis shows that NOD2 and IL-1b mRNA expression from mononuclear cells of RA patients is elevated in comparison with HD.

CONCLUSÃO:

These data suggest that NOD2 through caspase-1 and RIPK2 pathway might have an important role in the inflammatory modulation of RA.

Instituição de Fomento: FAPEAM – Fundação de Amparo a Pesquisa do Estado do Amazonas e FAPESP – Fundação de Amparo a Pesquisa do Estado de São Paulo

Palavras-chave: inflamação, artrite reumatóide, leucócitos.