Annexin A1 attenuates cardiac diastolic dysfunction in mice with inflammatory arthritis.

Rheumatoid arthritis (RA) carries a twofold increased incidence of heart failure with preserved ejection fraction, accompanied by diastolic dysfunction, which can lead to death. The causes of diastolic dysfunction are unknown, and there are currently no well-characterized animal models for studying these mechanisms. Current medications for RA do not have marked beneficial cardio-protective effects. K/BxN F1 progeny and KRN control mice were analyzed over time for arthritis development, monitoring left ventricular diastolic and systolic function using echocardiography. Excised hearts were analyzed by flow cytometry, qPCR, and histology. In pharmacological experiments, K/BxN F1 mice were treated with human recombinant AnxA1 (hrAnxA1, 1 µg/mouse) or vehicle daily. K/BxN F1 mice exhibited fully developed arthritis with normal cardiac function at 4 wk; however, by week 8, all mice displayed left ventricular diastolic dysfunction with preserved ejection fraction. This dysfunction was associated with cardiac hypertrophy, myocardial inflammation and fibrosis, and inflammatory markers. Daily treatment of K/BxN F1 mice with hrAnxA1 from weeks 4 to 8 halted progression of the diastolic dysfunction. The treatment reduced cardiac transcripts of proinflammatory cytokines and profibrotic markers. At the cellular level, hrAnxA1 decreased activated T cells and increased MHC IIlow macrophage infiltration in K/BxN F1 hearts. Similar effects were obtained when hrAnxA1 was administered from week 8 to week 15. We describe an animal model of inflammatory arthritis that recapitulates the cardiomyopathy of RA. Treatment with hrAnxA1 after disease onset corrected the diastolic dysfunction through modulation of both fibroblast and inflammatory cell phenotype within the heart.

Mecanismos de ação da anexina A1 na doença intestinal inflamatória tratada com infliximabe / Annexin A1 pathways triggered in the inflammatory bowel disease treated with infliximab

As doenças inflamatórias intestinais (DIIs) são enfermidades crônicas desencadeadas por grave inflamação no trato gastrointestinal. Entre os mediadores imunes envolvidos na patogênese das DIIs, o fator de necrose tumoral alfa (TNF-α) e sugerido como citocina primordial. Assim, ferramentas de inativação da via do TNF-α, como o infliximabe (IFX), tem sido amplamente aplicadas no tratamento destas doenças. Embora o IFX seja eficaz na indução/manutenção de remissão das DIIs, ainda há relatos de efeitos adversos ou pacientes refratários a imunoterapia. Por esse motivo, e emergente a necessidade de identificar biomarcadores associados ao sucesso das terapias biológicas. Estudos prévios em pacientes com Doença de Crohn (DC) mostraram que a expressão da proteína anti-inflamatória anexina A1 (AnxA1) sistêmica e na mucosa intestinal e aumentada após IFX e correlacionada com a melhora da qualidade de vida. A AnxA1 e o seu peptídeo N-terminal, Ac2-26, desempenham suas funções na resolução da inflamação via receptores para peptídeo formilado (FPRs). No presente estudo, nós investigamos de que maneira os FPRs e a AnxA1 participam dos mecanismos do IFX. No modelo de colite experimental induzida por dextran sulfato de sódio (DSS) em camundongos selvagens (WT) e deficientes para AnxA1 endógena (AnxA1-/-), o IFX atenuou as manifestações clínicas da doença apenas em animais WT. O bloqueio dos FPRs com o antagonista Boc-2 reverteu a melhora observada nos animais tratados, enquanto a ausência da AnxA1 endógena revogou completamente a eficácia do tratamento. Ainda, a resposta inflamatória da colite foi exacerbada nos animais AnxA1-/- após IFX, que apresentaram redução de células T regulatórias e aumento da MMP9 no colon, encurtamento do intestino grosso, ausência de melhora histológica e mortalidade de 50%. Nos animais WT, por sua vez, o bloqueio dos FPRs impediu a melhora clínica e a regeneração das criptas mucosas, com desorganização da ß-actina e da borda em escova. Nas células epiteliais do intestino da linhagem Caco-2 estimuladas por TNF-α in vitro, confirmamos que os efeitos protetivos do IFX nas junções celulares são perdidos após bloqueio do FPR1 e do FPR2, comprometendo a integridade desta barreira. No colon, o IFX induziu a expressão e secreção da AnxA1 em células da lamina própria após colite, e essa secreção foi dose-dependente em células da lamina própria tratadas ex vivo, demonstrando que a secreção da AnxA1 por células do tecido conjuntivo pode constituir um dos mecanismos resolutivos desta terapia. Em humanos, o tratamento com IFX na DC não modificou as expressões de FPR1 e FPR2 nos leucócitos circulantes ou da AnxA1 plasmática, não permitindo a diferenciação de pacientes responsivos ou não. No entanto, a AnxA1 tecidual estava aumentada em pacientes que respondem ao IFX, e os níveis de AnxA1 e FPR1 foram negativamente correlacionados a remissão histológica. Por fim, análises de bioinformática revelaram expressões diferenciais dos mRNAs de FPR1, FPR2 e AnxA1 no colon entre pacientes remissivos ou refratários mesmo antes do início das infusões, mas esse mesmo padrão não foi observado nos PBMCs do sangue. Em conclusão, sugerimos que a indução da AnxA1 pode ser um dos mecanismos de resolução do IFX, e que é complementado pela ativação de FPRs. Ainda, estes marcadores podem apresentar valor preditivo da eficácia do IFX, contribuindo para o alcance da remissão da DC de maneira mais rápida e permanente

Inflammatory bowel diseases (IBDs) are chronic debilitating illnesses triggered by severe inflammation of the gastrointestinal tract. The tumor necrosis factor alpha (TNF-α) is pointed out as a primordial mediator of IBD pathogenesis; thus, inactivating tools targeting this cytokine have been widely used to treat these diseases. Although IFX is very efficient in inducing/maintaining remission in patients with IBD, side effects and unresponsiveness are still reported, emerging the need for the identification of biomarkers linked to therapeutical efficacy. In the Crohns disease (CD), systemic and tissue expressions of the anti-inflammatory protein, annexin A1 (AnxA1), are increased after IFX treatment and correlate with life quality improvement according to previous reports. AnxA1 and its N-terminal peptide, Ac2-26, act via formyl peptide receptors (FPRs); therefore, the present investigation aimed to understand how FPRs and AnxA1 participate in IFX mechanisms. In the experimental colitis model induced by dextran sulphate sodium (DSS) in wild-type (WT) and AnxA1-deficient mice (AnxA1-/-), IFX attenuated the clinical manifestations only in the WT group. FPRs blockade using the antagonist, Boc-2, impaired IFX effects in WT mice, while AnxA1 absence completely abrogated its efficacy. Furthermore, the inflammatory response was exacerbated after IFX in AnxA1-/- mice, with reduced T regulatory cells, increased tissue MMP9, large intestine shortening, lack of histological remission and 50% mortality. In WT mice, FPR blockade reverted the clinical recovery and mucosal crypts regeneration, with b-actina and brush border disorganization. Using the intestinal epithelial cell line Caco-2 stimulated with TNF-α in vitro, we confirmed that IFX protective effects on tight junctions are lost after FPR1 and FPR2 blockade, compromising the barrier integrity. In the colonic tissue, the expression and secretion of AnxA1 were induced by IFX after colitis. This secretion was shown to be dose-dependent in cells from the intestinal lamina propria treated ex vivo, demonstrating that secreted AnxA1 could constitute one of the resolutive mechanisms of that therapy. In humans with CD, IFX did not modify the expressions of FPR1 and FPR2 in circulating leukocytes or the plasma AnxA1 levels, not differentiating patients responsive or not. However, tissue AnxA1 expression was augmented in responsive patients, and AnxA1/FPR1 levels were negatively correlated with histological remission. Finally, bioinformatic analyses revealed differential expression of FPR1, FPR2 and AnxA1 mRNAs in the colon among remittent or refractory patients even before the beginning of infusions, which was not observed for samples of blood PBCM. In conclusion, we suggest that inducing tissue AnxA1 might be one of the resolution mechanisms of IFX, which is complemented by the activation of FPRs. Moreover, these markers could present predictive value of IFX efficacy, contributing to reaching an early and more permanent remission in IBD