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- Andappan, Murugaiah M. S., et al.
(författare)
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From the First Selective Non-Peptide AT(2) Receptor Agonist to Structurally Related Antagonists
- 2012
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Ingår i: Journal of Medicinal Chemistry. - : American Chemical Society (ACS). - 0022-2623 .- 1520-4804. ; 55:5, s. 2265-2278
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Tidskriftsartikel (refereegranskat)abstract
- A para substitution pattern of the phenyl ring is a characteristic feature of the first reported selective AT(2) receptor agonist M024/C21 (1) and all the nonpeptidic AT(2) receptor agonists described so far. Two series of compounds structurally related to 1 but with a meta substitution pattern have now been synthesized and biologically evaluated for their affinity to the AT(1) and AT(2) receptors. A high AT(2)/AT(1) receptor selectivity was obtained with all 41 compounds synthesized, and the majority exhibited K-i ranging from 2 to 100 nM. Five compounds were evaluated for their functional activity at the AT(2) receptor, applying a neurite outgrowth assay in NG108-15 cells.. Notably, four of the five compounds, with representatives from both series, acted as potent AT(2) receptor antagonists. These compounds were found to be considerably more effective than PD 123,319, the standard AT(2) receptor antagonist used in most laboratories. No AT(2) receptor antagonists were previously reported among the derivatives with a para substitution pattern. Hence, by a minor modification of the agonist 1 it could be transformed into the antagonist, compound 38. These compounds should serve as valuable tools in the assessment of the role of the AT(2) receptor in more complex physiological models.
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| 3. |
- Bitar, Milad S., et al.
(författare)
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Inflammation and apoptosis in aortic tissues of aged type II diabetes : Amelioration with alpha-lipoic acid through phosphatidylinositol 3-kinase/Akt- dependent mechanism
- 2010
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Ingår i: Life Sciences. - : Elsevier BV. - 0024-3205 .- 1879-0631. ; 86:23-24, s. 844-853
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Tidskriftsartikel (refereegranskat)abstract
- Aims: Endothelial dysfunction is a key triggering event in the development of cardiovascular diseases and the current study explored this phenomenon in the context of inflammation, apoptosis, reactive oxygen species (ROS) and the phosphatidylinositol 3-kinase (PI3K)/Akt signaling pathway during chronic diabetes. Main methods: alpha-Lipoic acid (ALA) and wortmannin (WM) were chronically administered to aged Goto Kakizaki (GK) rats, a genetic model of non-obese type II diabetes. Key indices of inflammation, apoptosis and oxidative stress were assessed using western blotting, real-time PCR and immunofluoresence-based techniques. Key findings: A chronic inflammation (e.g., increased mRNA/protein levels of INF-alpha, ICAM, fractalkine, CD-68, myeloperoxidase) in connection with increased caspase-based apoptotic cell death and heightened state of oxidative stress (HSOS)- appear to exist in diabetic cardiovascular tissues. An assessment of NF-kappa B dynamics in aged diabetic vessels revealed not only a marked increase in cytosolic phosphorylated levels of I kappa B-alpha, NIK, IRK but also an enhancement in nuclear localization of p65 concomitantly with augmented NF-kappa B-DNA binding activity. Most of the aforementioned cardiovascular-based diabetic abnormalities including reduced activities of PI3K and Akt kinase were ameliorated following chronic ALA therapy. WM, given to GK rats negated the anti-inflammatory and anti-apoptotic actions of ALA. Significance: Our data highlight a unifying mechanism whereby HSOS through an induction of NF-kappa B activity together with an impairment in PI3K/Akt pathway favors pro-inflammatory/pro-apoptotic diabetic vascular milieu that culminate in the onset of endothelial dysfunction, a phenomenon which appears to be amenable to treatment with antioxidants and/or PI3/Akt mimetics (e.g., ALA).
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| 5. |
- Mahalingam, A. K., et al.
(författare)
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Selective angiotensin II AT(2) receptor agonists with reduced CYP 450 inhibition
- 2010
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Ingår i: Bioorganic & Medicinal Chemistry. - : Elsevier BV. - 0968-0896 .- 1464-3391. ; 18:12, s. 4570-4590
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Tidskriftsartikel (refereegranskat)abstract
- Structural alterations to the benzylic position of the first drug-like selective angiotensin II AT(2) receptor agonist (1) have been performed, with the emphasis to reduce the CYP 450 inhibitory property of the initial structure. The imidazole moiety, responsible for the CYP 450 inhibitory effect in 1, was replaced with various heterocycles. In addition, the modes of attachment of the heterocycles, that is, carbon versus nitrogen attachment, and introduction of carbonyl functionalities to the benzylic position have been evaluated. In all the three series, AT(2) receptor ligands with affinity in the lower nanomolar range were identified. None of the analogues, regardless of the substituents, exhibited any affinity for the AT(1) receptor. Compounds with substantially reduced inhibition of the CYP 450 enzymes were obtained. Among them the compound 60 was found to induce neurite elongation in NG 108-15 cells and served as potent AT(2) selective agonist.
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