Suppression of inflammation response by a novel A₃ adenosine receptor agonist thio-Cl-IB-MECA through inhibition of Akt and NF-κB signaling.

Adenosine, a purine nucleoside, is released from metabolically active cells into extracellular space and plays an important role in various pathophysiological processes. Adenosine regulates many biological responses including inflammation by the interaction with their receptors such as A₁, A(2A), A(2B), and A₃. Especially, A₃ adenosine receptor (A₃AR) is considered to be expressed in macrophage cells. To the end, A₃AR agonists have been reported to have an anti-inflammatory activity. In our continuous efforts to develop new anti-inflammatory agents, we found a novel adenosine analog, 2-chloro-N⁶-(3-iodobenzyl)-4'-thioadenosine-5'-N-methyluronamide (thio-Cl-IB-MECA), was a potent human A₃AR agonist. The study was designed to investigate whether thio-Cl-IB-MECA has an anti-inflammatory potential in mouse macrophage RAW 264.7 cells and mouse sepsis model in vivo. Thio-Cl-IB-MECA exhibited an effective anti-inflammatory activity. The expression of pro-inflammatory biomarkers including inducible nitric oxide synthase (iNOS), interleukin-1β (IL-1β), and tumor necrosis factor (TNF-α) was suppressed by the treatment of thio-Cl-IB-MECA in the protein and mRNA levels in lipopolysaccharide (LPS)-stimulated mouse macrophage RAW 264.7 cells. Further examination revealed that thio-Cl-IB-MECA inhibited LPS-induced phosphatidylinositol 3-kinase (PI3 kinase)/Akt activation, NF-kB binding activity, and β-catenin expression. In addition, in in vivo LPS-induced mouse endotoxemia model, thio-Cl-IB-MECA exerted the increase of survival rate compared to vehicle-treated mouse. The analysis of the protein levels of iNOS, IL-1β, and TNF-α was also suppressed by the compound-treated groups in lung tissues. These results suggest that thio-Cl-IB-MECA might have an anti-inflammatory activity through the inhibition of pro-inflammatory cytokine expression by modulating PI3K/Akt and NF-κB signaling pathways.

Lee HS ，Chung HJ ，Lee HW ，Jeong LS ，Lee SK ... -  《-》

Thio-Cl-IB-MECA, a novel A₃ adenosine receptor agonist, suppresses angiogenesis by regulating PI3K/AKT/mTOR and ERK signaling in endothelial cells.

Although A₃AR agonists exhibit a variety of biological activities including anticancer effects, their possible anti-angiogenic effects have not yet been investigated. In the present study, we assayed the anti-angiogenic activity of thio-Cl-IB-MECA, a novel A₃AR agonist, in cultured HUVECs and mES/EB-derived endothelial cells. Thio-Cl-IB-MECA inhibited migration and tube formation by endothelial cells and dramatically decreased ex vivo microvessel sprouting in cultured mouse aortic rings. The anti-angiogenic activity of thio-Cl-IB-MECA was associated with suppression of the expression of the endothelial biomarker PECAM via regulation of PI3K/AKT/mTOR and ERK signaling in mES/EB-derived endothelial cells.

Kim GD ，Oh J ，Jeong LS ，Lee SK ... -  《-》

Activation of the adenosine A3 receptor in RAW 264.7 cells inhibits lipopolysaccharide-stimulated tumor necrosis factor-alpha release by reducing calcium-dependent activation of nuclear factor-kappaB and extracellular signal-regulated kinase 1/2.

Martin L ，Pingle SC ，Hallam DM ，Rybak LP ，Ramkumar V ... -  《JOURNAL OF PHARMACOLOGY AND EXPERIMENTAL THERAPEUTICS》

Cl-IB-MECA enhances TRAIL-induced apoptosis via the modulation of NF-kappaB signalling pathway in thyroid cancer cells.

Morello S ，Sorrentino R ，Porta A ，Forte G ，Popolo A ，Petrella A ，Pinto A ... -  《-》

Cl-IB-MECA enhances TNF-α release in peritoneal macrophages stimulated with LPS.

Adenosine receptor A3 (A3R) belongs to the Gi/Gq-coupled receptor family, that leads to the intracellular cAMP reduction and intracellular calcium increase, respectively. A3R is widely expressed and it can play a crucial role in many patho-physiological conditions, including inflammation. Here we investigate the effect of Cl-IB-MECA, A3R agonist, on the production of TNF-α. We found that Cl-IB-MECA enhances LPS-induced TNF-α release in peritoneal macrophages. This effect is reduced by MRS1191, A3R antagonist and by forskolin, activator of adenylyl cyclase. pIκBα increased in LPS+Cl-IB-MECA-treated macrophages, while total IκB kinase-β (IKKβ) reduced. Indeed, p65NF-κB nuclear translocation increased in cells treated with LPS+Cl-IB-MECA. Moreover, IMD 0354, IKKβ inhibitor, significantly abrogated the effect of Cl-IB-MECA on TNF-α release. Inhibition of protein kinase C (PKC) significantly reduced Cl-IB-MECA-induced TNF-α release in LPS-stimulated macrophages. Furthermore, LY-294002, PI3K inhibitor, reduced the TNF-α production enhanced by Cl-IB-MECA, although the phosphorylation status of Akt did not change in cells treated with LPS+Cl-IB-MECA than LPS alone. In summary, these data show that Cl-IB-MECA is able to enhance TNF-α production in LPS-treated macrophages in an NF-κB- dependent manner.

Forte G ，Sorrentino R ，Montinaro A ，Pinto A ，Morello S ... -  《-》