Positive Modulators of the N-Methyl-d-aspartate Receptor: Structure–Activity Relationship Study of Steroidal 3-Hemiesters

Abstract

Here, we report the synthesis of pregn-5-ene and androst-5-ene dicarboxylic acid esters and explore the structure-activity relationship (SAR) for their modulation of N-methyl-d-aspartate receptors (NMDARs). All compounds were positive modulators of recombinant GluN1/GluN2B receptors (EC varying from 1.8 to 151.4 μM and E varying from 48% to 452%). Moreover, 10 compounds were found to be more potent GluN1/GluN2B receptor modulators than endogenous pregnenolone sulfate (EC = 21.7 μM). The SAR study revealed a relationship between the length of the residues at carbon C-3 of the steroid molecule and the positive modulatory effect at GluN1/GluN2B receptors for various D-ring modifications. A selected compound, 20-oxo-pregnenolone hemiadipate, potentiated native NMDARs to a similar extent as GluN1/GluN2A-D receptors and inhibited AMPARs and GABAR responses. These results provide a unique opportunity for the development of new steroid based drugs with potential use in the treatment of neuropsychiatric disorders involving hypofunction of NMDARs.

Visualizing pregnenolone sulfate-like modulators of NMDA receptor function reveals intracellular and plasma-membrane localization

“…Our results provide new information about structure-activity relationships while revealing some of the structural properties of compounds important for cellular retention and accumulation. As with other recent results (Krausova et al, 2018), our data show that NMDAR potentiation can be retained with alterations to the PREGS structure. Specifically, our results demonstrate that bioactivity tolerates side chain alterations to add a click label (KK-169, KK-181) or click label plus photolabel (MQ-189).…”

Site of Action of Brain Neurosteroid Pregnenolone Sulfate at the N-Methyl-D-Aspartate Receptor

“…There is considerable interest in discovering drugs that augment NMDAR function and could be used to treat neuropsychiatric diseases associated with receptor hypofunction. Among powerful allosteric modulators of NMDARs are natural substances, including neuroactive steroids and newly synthesized steroid-like compounds (Krausova et al, 2018). Neurosteroids represent a broad class of compounds playing multiple biological roles both during development and in various physiological states (Dubrovsky, 2005).…”

Surface Expression, Function, and Pharmacology of Disease-Associated Mutations in the Membrane Domain of the Human GluN2B Subunit

“…The sensitivity of the mutant receptors to extracellular PE-S, a steroid that has a positive allosteric and subunit-dependent effect at NMDAR (with preference for GluN2A/B subunits) (Wu et al, 1991 ; Horak et al, 2006 ), was evaluated by generating dose-response curves for the potentiation of responses to glutamate. In addition, we analyzed the potentiating effect for AND-hSuc, a more potent synthetic PE-S analog (Krausova et al, 2018 ). Since the effect of steroids with a potentiating effect at NMDAR is disuse-dependent (Horak et al, 2004 ), a low concentration of glutamate (1 μM) was used in these experiments.…”

“…Therapeutic strategies for the development of new effective drugs for rectifying loss-of-function variants associated with diminution of the receptor P o may encompass PE-S and its derivatives, since these compounds have a positive allosteric effect that is specifically mediated by the increase in the receptor P o (Horak et al, 2004 ; Korinek et al, 2011 ). Both an endogenously occurring neurosteroid PE-S (Wu et al, 1991 ; Bowlby, 1993 ) and its more potent synthetic analog AND-hSuc (Krausova et al, 2018 ) were approximately as effective at WT as at the hGluN1/hGluN2B(V558I; W607C; V618G; and G820A) receptors. Interestingly, both steroids potentiated the amplitude of tonic and synaptic-like responses more profoundly when studied at hGluN1/hGluN2B(L825V) receptors, indicating their prospective use in personalized therapies.…”

“…Glycine (30 μM), an NMDAR co-agonist, was present in the control and test solutions. All steroid solutions were made from freshly prepared 20 mM 20-oxo-pregn-5-en-3β-yl sulfate (PE-S; pregnenolone sulfate), and 5 mM androst-5-en-3β-yl hemisuccinate (AND-hSuc) (Krausova et al, 2018 ) stock in dimethyl sulfoxide (DMSO). The final dilution to ECS was made at 50°C and followed by 1 min sonication (SONOREX DIGITEC DT 100/H, BADELIN electronic, Berlin, Germany).…”