Potentiation of muscarinic M3 receptor activation through a new allosteric site with a novel positive allosteric modulator ASP8302

2021 ◽  
pp. JPET-AR-2021-000709
Author(s):  
Risa Okimoto ◽  
Katsutoshi Ino ◽  
Kenichiro Ishizu ◽  
Hajime Takamatsu ◽  
Kazuyuki Sakamoto ◽  
...  
2019 ◽  
Vol 116 (8) ◽  
pp. 3294-3299 ◽  
Author(s):  
Alex D. White ◽  
Fei Fang ◽  
Frédéric G. Jean-Alphonse ◽  
Lisa J. Clark ◽  
Hyun-Jung An ◽  
...  

The parathyroid hormone (PTH) and its related peptide (PTHrP) activate PTH receptor (PTHR) signaling, but only the PTH sustains GS-mediated adenosine 3′,5′-cyclic monophosphate (cAMP) production after PTHR internalization into early endosomes. The mechanism of this unexpected behavior for a G-protein–coupled receptor is not fully understood. Here, we show that extracellular Ca2+ acts as a positive allosteric modulator of PTHR signaling that regulates sustained cAMP production. Equilibrium and kinetic studies of ligand-binding and receptor activation reveal that Ca2+ prolongs the residence time of ligands on the receptor, thus, increasing both the duration of the receptor activation and the cAMP signaling. We further find that Ca2+ allostery in the PTHR is strongly affected by the point mutation recently identified in the PTH (PTHR25C) as a new cause of hypocalcemia in humans. Using high-resolution and mass accuracy mass spectrometry approaches, we identified acidic clusters in the receptor’s first extracellular loop as key determinants for Ca2+ allosterism and endosomal cAMP signaling. These findings coupled to defective Ca2+ allostery and cAMP signaling in the PTHR by hypocalcemia-causing PTHR25C suggest that Ca2+ allostery in PTHR signaling may be involved in primary signaling processes regulating calcium homeostasis.


2020 ◽  
Vol 477 (2) ◽  
pp. 459-459
Author(s):  
Lalith K. Chaganti ◽  
Shubhankar Dutta ◽  
Raja Reddy Kuppili ◽  
Mriganka Mandal ◽  
Kakoli Bose

2019 ◽  
Vol 10 (5) ◽  
pp. 754-760 ◽  
Author(s):  
Andrew J. Harvey ◽  
Thomas D. Avery ◽  
Laurent Schaeffer ◽  
Christophe Joseph ◽  
Belinda C. Huff ◽  
...  

2021 ◽  
Vol 22 (1) ◽  
Author(s):  
Cecilia Rustichelli ◽  
Elisa Bellei ◽  
Stefania Bergamini ◽  
Emanuela Monari ◽  
Flavia Lo Castro ◽  
...  

Abstract Background Neurosteroids affect the balance between neuroexcitation and neuroinhibition but have been little studied in migraine. We compared the serum levels of pregnenolone sulfate, pregnanolone and estradiol in women with menstrually-related migraine and controls and analysed if a correlation existed between the levels of the three hormones and history of migraine and age. Methods Thirty women (mean age ± SD: 33.5 ± 7.1) with menstrually-related migraine (MM group) and 30 aged- matched controls (mean age ± SD: 30.9 ± 7.9) participated in the exploratory study. Pregnenolone sulfate and pregnanolone serum levels were analysed by liquid chromatography-tandem mass spectrometry, while estradiol levels by enzyme-linked immunosorbent assay. Results Serum levels of pregnenolone sulfate and pregnanolone were significantly lower in the MM group than in controls (pregnenolone sulfate: P = 0.0328; pregnanolone: P = 0.0271, Student’s t-test), while estradiol levels were similar. In MM group, pregnenolone sulfate serum levels were negatively correlated with history of migraine (R2 = 0.1369; P = 0.0482) and age (R2 = 0.2826, P = 0.0025) while pregnenolone sulfate levels were not age-related in the control group (R2 = 0.04436, P = 0.4337, linear regression analysis). Conclusion Low levels of both pregnanolone, a positive allosteric modulator of the GABAA receptor, and pregnenolone sulfate, a positive allosteric modulator of the NMDA receptor, involved in memory and learning, could contribute either to headache pain or the cognitive dysfunctions reported in migraine patients. Overall, our results agree with the hypothesis that migraine is a disorder associated with a loss of neurohormonal integrity, thus supporting the therapeutic potential of restoring low neurosteroid levels in migraine treatment.


2019 ◽  
Vol 237 (1) ◽  
pp. 137-153 ◽  
Author(s):  
Aaron Kucinski ◽  
Kyra B. Phillips ◽  
Ajeesh Koshy Cherian ◽  
Martin Sarter

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