Contributions
Abstract: EP1458
Type: Poster Sessions
Abstract Category: Pathology and pathogenesis of MS - Experimental models
Introduction: A20, codified by TNFAIP3 gene, is an ubiquitin-ending enzyme involved in the inhibition of NF-kB and is a central gatekeeper in inflammation. Genetic variants in the TNFAIP3 locus are associated with several autoimmune disorders, including multiple sclerosis (MS). A significant A20 down-regulation is frequently observed in blood cells from MS patients, particularly in monocytes.
Aims: based to the crucial role of myeloid cells in the pathogenesis of MS, we aim to investigate the effects of A20 deficiency in these cells in vivo.
Methods: we generated the conditional knock-out (KO) murine model (A20lox::CX3CR1) crossing A20lox/lox mice with transgenic mice carrying the Cre recombinase under the control of a specific promoter for myeloid/microglial cells (CX3CR1). We performed cytofluorimetric and histologic analysis to characterize the phenotype of conditional homozygous KO mice (A20lox/lox::CX3CR1) compared to their wild type (WT) littermates (A20wt/wt::CX3CR1).
Results: KO mice show a mortality rate of 40% during post-natal development. Moreover, starting from 1 month of age they are smaller compared to the WT littermates, regardless of gender. At a cytofluorimetric analysis, spleens from 3-months old KO mice display a reduction in the percentage of CD11c+CD86+ dendritic cells, CD11b+Ly-6C+Ly-6G+ monocytes and CD11b+F4/80+ macrophages compared to WT. These findings are corroborated by the histological analysis, which highlights a massive hypertrophy of the spleen in KO mice. This is mainly due to the expansion of the red pulp, which is characterized by an increased extramedullary haematopoiesis with various degrees of normal differentiation. Spleen architecture is also altered by a partial substitution of the white pulp sheaths of lymphoid cells by myeloid cells.
Conclusions: the phenotypical analysis of the A20lox::CX3CR1 murine model clearly suggests a crucial role for A20 in the development of myeloid cells.
Disclosure: Serena Martire received speaker honoraria from Biogen.
Simona Perga received speaker honoraria from Biogen.
Francesca Montarolo received speaker honoraria from Biogen.
Michela Spadaro received speaker honoraria from Biogen.
Manuela Iezzi has nothing to disclose.
Antonio Bertolotto has received travel funding from Biogen Dompè, Biogen Idec, Merck Serono, Novartis, Sanofi-Aventis, Teva Pharmaceutical Industries Ltd., and Bayer Schering Pharma; received speaker honoraria from Biogen Dompè, Biogen Idec, Merck Serono, Novartis, Sanofi-Aventis, Teva Pharmaceutical Industries Ltd. and Bayer Schering Pharma; and receives research support from Merck-Serono, Biogen Idec, Biogen Dompè, Bayer Schering Pharma, Alenia Spazio, Italian Ministry of Health, and the Italian Multiple Sclerosis Society.
Abstract: EP1458
Type: Poster Sessions
Abstract Category: Pathology and pathogenesis of MS - Experimental models
Introduction: A20, codified by TNFAIP3 gene, is an ubiquitin-ending enzyme involved in the inhibition of NF-kB and is a central gatekeeper in inflammation. Genetic variants in the TNFAIP3 locus are associated with several autoimmune disorders, including multiple sclerosis (MS). A significant A20 down-regulation is frequently observed in blood cells from MS patients, particularly in monocytes.
Aims: based to the crucial role of myeloid cells in the pathogenesis of MS, we aim to investigate the effects of A20 deficiency in these cells in vivo.
Methods: we generated the conditional knock-out (KO) murine model (A20lox::CX3CR1) crossing A20lox/lox mice with transgenic mice carrying the Cre recombinase under the control of a specific promoter for myeloid/microglial cells (CX3CR1). We performed cytofluorimetric and histologic analysis to characterize the phenotype of conditional homozygous KO mice (A20lox/lox::CX3CR1) compared to their wild type (WT) littermates (A20wt/wt::CX3CR1).
Results: KO mice show a mortality rate of 40% during post-natal development. Moreover, starting from 1 month of age they are smaller compared to the WT littermates, regardless of gender. At a cytofluorimetric analysis, spleens from 3-months old KO mice display a reduction in the percentage of CD11c+CD86+ dendritic cells, CD11b+Ly-6C+Ly-6G+ monocytes and CD11b+F4/80+ macrophages compared to WT. These findings are corroborated by the histological analysis, which highlights a massive hypertrophy of the spleen in KO mice. This is mainly due to the expansion of the red pulp, which is characterized by an increased extramedullary haematopoiesis with various degrees of normal differentiation. Spleen architecture is also altered by a partial substitution of the white pulp sheaths of lymphoid cells by myeloid cells.
Conclusions: the phenotypical analysis of the A20lox::CX3CR1 murine model clearly suggests a crucial role for A20 in the development of myeloid cells.
Disclosure: Serena Martire received speaker honoraria from Biogen.
Simona Perga received speaker honoraria from Biogen.
Francesca Montarolo received speaker honoraria from Biogen.
Michela Spadaro received speaker honoraria from Biogen.
Manuela Iezzi has nothing to disclose.
Antonio Bertolotto has received travel funding from Biogen Dompè, Biogen Idec, Merck Serono, Novartis, Sanofi-Aventis, Teva Pharmaceutical Industries Ltd., and Bayer Schering Pharma; received speaker honoraria from Biogen Dompè, Biogen Idec, Merck Serono, Novartis, Sanofi-Aventis, Teva Pharmaceutical Industries Ltd. and Bayer Schering Pharma; and receives research support from Merck-Serono, Biogen Idec, Biogen Dompè, Bayer Schering Pharma, Alenia Spazio, Italian Ministry of Health, and the Italian Multiple Sclerosis Society.