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Discovery of a stable tripeptide targeting the N-domain of CRF1 receptor. Amino Acids 2020; 52:1337-1351. [PMID: 32996057 DOI: 10.1007/s00726-020-02895-4] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/24/2019] [Accepted: 09/19/2020] [Indexed: 10/23/2022]
Abstract
The corticotropin-releasing factor (CRF) and its CRF1 receptor (CRF1R) play a central role in the maintenance of homeostasis. Malfunctioning of the CRF/CRF1R unit is associated with several disorders, such as anxiety and depression. Non-peptide CRF1R-selective antagonists have been shown to exert anxiolytic and antidepressant effects on experimental animals. However, none of them is in clinical use today because of several side effects, thus demonstrating the need for the development of other more suitable CRF1R antagonists. In an effort to develop novel CRF1R antagonists we designed, synthesized and chemically characterized two tripeptide analogues of CRF, namely (R)-LMI and (S)-LMI, having their Leu either in R (or D) or in S (or L) configuration, respectively. Their design was based on the crystal structure of the N-extracellular domain (N-domain) of CRF1R/CRF complex, using a relevant array of computational methods. Experimental evaluation of the stability of synthetic peptides in human plasma has revealed that (R)-LMI is proteolytically more stable than (S)-LMI. Based on this finding, (R)-LMI was selected for pharmacological characterization. We have found that (R)-LMI is a CRF antagonist, inhibiting (1) the CRF-stimulated accumulation of cAMP in HEK 293 cells expressing the CRF1R, (2) the production of interleukins by adipocytes and (3) the proliferation rate of RAW 264.7 cells. (R)-LMI likely blocked agonist actions by interacting with the N-domain of CRF1R as suggested by data using a constitutively active chimera of CRF1R. We propose that (R)-LMI can be used as an optimal lead compound in the rational design of novel CRF antagonists.
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Sakellaris S, Matsoukas MT, Karageorgos V, Poulaki S, Kuppast B, Margioris A, Venihaki M, Fahmy H, Liapakis G. Selective antagonism of CRF1 receptor by a substituted pyrimidine. Hormones (Athens) 2019; 18:215-221. [PMID: 30980254 DOI: 10.1007/s42000-019-00105-9] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/26/2018] [Accepted: 03/20/2019] [Indexed: 01/13/2023]
Abstract
The corticotrophin-releasing factor (CRF) and its type 1 receptor (CRF1R) regulate the hypothalamic-pituitary-adrenal axis, as well as other systems, thus playing a crucial role in the maintenance of homeostasis. Non-peptide CRF1R-selective antagonists exert therapeutic effects on experimental animals with abnormal regulation of their homeostatic mechanisms. However, none of them is as yet in clinical use. In an effort to develop novel small non-peptide CRF1R-selective antagonists, we have synthesized a series of substituted pyrimidines described in a previous study. These small molecules bind to CRF1R, with analog 3 having the highest affinity. Characteristic structural features of analog 3 are a N,N-bis(methoxyethyl)amino group at position 6 and a methyl in the alkythiol group at position 5. Based on the binding profile of analog 3, we selected it in the present study for further pharmacological characterization. The results of this study suggest that analog 3 is a potent CRF1R-selective antagonist, blocking the ability of sauvagine, a CRF-related peptide, to stimulate cAMP accumulation in HEK 293 cells via activation of CRF1R, but not via CRF2R. Moreover, analog 3 blocked sauvagine to stimulate the proliferation of macrophages, further supporting its antagonistic properties. We have also constructed molecular models of CRF1R to examine the interactions of this receptor with analog 3 and antalarmin, a prototype CRF1R-selective non-peptide antagonist, which lacks the characteristic structural features of analog 3. Our data facilitate the design of novel non-peptide CRF1R antagonists for clinical use.
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Affiliation(s)
- Stelios Sakellaris
- Department of Pharmacology, School of Medicine, University of Crete, Voutes, Heraklion, 71003, Crete, Greece
| | | | - Vlasios Karageorgos
- Department of Pharmacology, School of Medicine, University of Crete, Voutes, Heraklion, 71003, Crete, Greece
| | - Smaragda Poulaki
- Department of Clinical Chemistry, School of Medicine, University of Crete, Voutes, Heraklion, 71003, Crete, Greece
| | - Bhimanna Kuppast
- Department of Pharmaceutical Sciences, College of Pharmacy, South Dakota State University, Brookings, SD, 57007, USA
| | - Andrew Margioris
- Department of Clinical Chemistry, School of Medicine, University of Crete, Voutes, Heraklion, 71003, Crete, Greece
| | - Maria Venihaki
- Department of Clinical Chemistry, School of Medicine, University of Crete, Voutes, Heraklion, 71003, Crete, Greece
| | - Hesham Fahmy
- Department of Pharmaceutical Sciences, College of Pharmacy, South Dakota State University, Brookings, SD, 57007, USA
| | - George Liapakis
- Department of Pharmacology, School of Medicine, University of Crete, Voutes, Heraklion, 71003, Crete, Greece.
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