RESUMO
AIMS: To investigate the hypothesis that alteration in histone acetylation/deacetylation triggers aberrant STAT1/MyD88 expression in macrophages from diabetics. Increased STAT1/MyD88 expression is correlated with sterile inflammation in type 1 diabetic (T1D) mice. METHODS: To induce diabetes, we injected low-doses of streptozotocin in C57BL/6 mice. Peritoneal or bone marrow-differentiated macrophages were cultured in 5mM (low) or 25mM (high glucose). ChIP analysis of macrophages from nondiabetic or diabetic mice was performed to determine acetylation of lysine 9 in histone H3 in MyD88 and STAT1 promoter regions. Macrophages from diabetic mice were treated with the histone acetyltransferase inhibitor anacardic acid (AA), followed by determination of mRNA expression by qPCR. RESULTS: Increased STAT1 and MyD88 expression in macrophages from diabetic but not naive mice cultured in low glucose persisted for up to 6days. Macrophages from diabetic mice exhibited increased activity of histone acetyltransferases (HAT) and decreased histone deacetylases (HDAC) activity. We detected increased H3K9Ac binding to Stat1/Myd88 promoters in macrophages from T1D mice and AA in vitro treatment reduced STAT1 and MyD88 mRNA expression. CONCLUSIONS/INTERPRETATION: These results indicate that histone acetylation drives elevated Stat1/Myd88 expression in macrophages from diabetic mice, and this mechanism may be involved in sterile inflammation and diabetes comorbidities.
Assuntos
Diabetes Mellitus Tipo 1/metabolismo , Regulação da Expressão Gênica , Histona Acetiltransferases/metabolismo , Histona Desacetilases/metabolismo , Macrófagos/metabolismo , Fator 88 de Diferenciação Mieloide/metabolismo , Fator de Transcrição STAT1/metabolismo , Acetilação/efeitos dos fármacos , Animais , Células da Medula Óssea/efeitos dos fármacos , Células da Medula Óssea/imunologia , Células da Medula Óssea/metabolismo , Células da Medula Óssea/patologia , Células Cultivadas , Diabetes Mellitus Tipo 1/induzido quimicamente , Diabetes Mellitus Tipo 1/imunologia , Diabetes Mellitus Tipo 1/patologia , Inibidores Enzimáticos/farmacologia , Epigênese Genética/efeitos dos fármacos , Regulação da Expressão Gênica/efeitos dos fármacos , Glucose/metabolismo , Histona Acetiltransferases/antagonistas & inibidores , Histonas/metabolismo , Macrófagos/efeitos dos fármacos , Macrófagos/imunologia , Macrófagos/patologia , Macrófagos Peritoneais/efeitos dos fármacos , Macrófagos Peritoneais/imunologia , Macrófagos Peritoneais/metabolismo , Macrófagos Peritoneais/patologia , Masculino , Camundongos Endogâmicos C57BL , Fator 88 de Diferenciação Mieloide/genética , Concentração Osmolar , Regiões Promotoras Genéticas/efeitos dos fármacos , Processamento de Proteína Pós-Traducional/efeitos dos fármacos , Fator de Transcrição STAT1/genética , Estreptozocina/toxicidadeRESUMO
The monoterpene gamma-terpinene is a natural compound present in essential oils of a wide variety of plants, including the Eucalyptus genus, which has been reported to possess anti-inflammatory activity. The goal of this study was to evaluate the effect of gamma-terpinene on several in vivo experimental models of acute inflammation. Swiss mice were pretreated with gamma-terpinene and subjected to protocols of paw edema with different phlogistic agents such as carrageenan, prostaglandin-E2, histamine, or bradykinin. The microvascular permeability was measured by intraperitoneal injection of acetic acid and measuring the amount of protein extravasation. Carrageenan-induced peritonitis was used to analyze the effect of gamma-terpinene on inflammatory cell migration and cytokine production. We also developed an acute lung injury protocol to define the anti-inflammatory effect of gamma-terpinene. Mice pretreated with gamma-terpinene displayed reduced paw edema induced by carrageenan from 1-24 h after challenge. A similar reduction was observed when gamma-terpinene was administered after stimulation with PGE2, bradykinin, and histamine. Treatment with gamma-terpinene also inhibited fluid extravasation in the acetic acid model of microvascular permeability. In a carrageenan-induced peritonitis model, gamma-terpinene treatment reduced neutrophil migration as well as the production of interleukin-1ß and tumor necrosis factor-α when compared to nontreated animals, and in the acute lung injury protocol, gamma-terpinene diminished the neutrophil migration into lung tissue independently of the total protein extravasation in the lung. These data demonstrate that, in different models of inflammation, treatment with gamma-terpinene alleviated inflammatory parameters such as edema and pro-inflammatory cytokine production, as well as cell migration into the inflamed site, and that this monoterpene has anti-inflammatory properties.
