Publicação
Adrenoceptor-stimulated inflammatory response in stress-induced serum amyloid A synthesis
| Resumo: | Rationale Stressful life events are suggested to contribute to the development of various pathologies, such as cardiovascular disorders, whose etiopathogenesis is highly associated with elevated levels of serum amyloid A (SAA) proteins. SAA synthesis inthe liver isregulated bya complex network ofcytokines actingindependently orinconcert withvarious hormones/stimulants including the stress-activated sympathetic nervous system. Objective This study aims to investigate the underlying mechanisms that regulate the stress-induced hepatic synthesis of SAA, with particular focus on adrenoceptors (AR), major components of the sympathoadrenal response to stress. Methods and results We demonstrated that repeated stress elevates IL-1β, IL-6, and TNFα serum levels in mice, accompanied by increased synthesis and secretion of hepatic SAA1/2 and SAA3, an effect that was blocked by AR antagonists. Moreover, stimulation ofα1- andβ1/2-ARsmimics thestress effectonSAA1/2 regulation, whereas α2-AR stimulation exhibitsa relatively weakimpactonSAA.InsupportoftheessentialcytokinecontributionintheAR-agonistinducedSAAproductionisthefactthat theanti-inflammatorydrug,sodiumsalicylate,preventedtheAR-stimulatedhepaticSAA1/2synthesisbyreducingIL-1βlevels, whereasIL-1βinhibitionwithAnakinramimicsthissodiumsalicylatepreventiveeffect,thusindicatingacrucial rolefor IL-1β. Interestingly, the AR-driven SAA3 synthesis was elevated by sodium salicylate in a TNFα-dependent way, supporting diverse and complex regulatory roles of cytokines in SAA production. In contrast to α1/α2-AR, the β1/2-AR-mediated SAA1/2 and SAA3 upregulation cannot be reversed by fenofibrate, a hypolipidemic drug with anti-inflammatory properties. Conclusion Taken together, these findings strongly support a critical role of the AR-stimulated inflammatory response in the hepatic SAA production under stressful conditions, highlighting distinct AR type-specific mechanisms that regulate the hepatic synthesis of SAA1/2 and SAA3. |
|---|---|
| Autores principais: | Konstandi, Maria |
| Outros Autores: | Sotiropoulos, I.; Matsubara, Tsutomu; Malliou, Foteini; Katsogridaki, Alexandra; Andriopoulou, Christina E.; Gonzalez, Frank J. |
| Assunto: | Adrenoceptors IL-1β IL-6 SAA1/2 SAA3 Stress TNFα SAA1 2 IL-1 beta |
| Ano: | 2019 |
| País: | Portugal |
| Tipo de documento: | artigo |
| Tipo de acesso: | acesso aberto |
| Instituição associada: | Universidade do Minho |
| Idioma: | inglês |
| Origem: | RepositóriUM - Universidade do Minho |
| Resumo: | Rationale Stressful life events are suggested to contribute to the development of various pathologies, such as cardiovascular disorders, whose etiopathogenesis is highly associated with elevated levels of serum amyloid A (SAA) proteins. SAA synthesis inthe liver isregulated bya complex network ofcytokines actingindependently orinconcert withvarious hormones/stimulants including the stress-activated sympathetic nervous system. Objective This study aims to investigate the underlying mechanisms that regulate the stress-induced hepatic synthesis of SAA, with particular focus on adrenoceptors (AR), major components of the sympathoadrenal response to stress. Methods and results We demonstrated that repeated stress elevates IL-1β, IL-6, and TNFα serum levels in mice, accompanied by increased synthesis and secretion of hepatic SAA1/2 and SAA3, an effect that was blocked by AR antagonists. Moreover, stimulation ofα1- andβ1/2-ARsmimics thestress effectonSAA1/2 regulation, whereas α2-AR stimulation exhibitsa relatively weakimpactonSAA.InsupportoftheessentialcytokinecontributionintheAR-agonistinducedSAAproductionisthefactthat theanti-inflammatorydrug,sodiumsalicylate,preventedtheAR-stimulatedhepaticSAA1/2synthesisbyreducingIL-1βlevels, whereasIL-1βinhibitionwithAnakinramimicsthissodiumsalicylatepreventiveeffect,thusindicatingacrucial rolefor IL-1β. Interestingly, the AR-driven SAA3 synthesis was elevated by sodium salicylate in a TNFα-dependent way, supporting diverse and complex regulatory roles of cytokines in SAA production. In contrast to α1/α2-AR, the β1/2-AR-mediated SAA1/2 and SAA3 upregulation cannot be reversed by fenofibrate, a hypolipidemic drug with anti-inflammatory properties. Conclusion Taken together, these findings strongly support a critical role of the AR-stimulated inflammatory response in the hepatic SAA production under stressful conditions, highlighting distinct AR type-specific mechanisms that regulate the hepatic synthesis of SAA1/2 and SAA3. |
|---|