163.07
Efficacy of Subtype-Selective, Full vs Partial M4 Muscarinic Receptor Agonists in Modulating Amphetamine-Induced Brain Activity Assessed by Functional MRI (fMRI) in Rats
S. Bardehle,1 G. L. Suidan,1 H. Nguyen,1
S. Chakilam,1 G. Gokulrangan,1 R. Immonen,2 A. Shatillo,2 P. A. Iredale1
BACKGROUND
- The M4 muscarinic acetylcholine receptor (mAChR) is a transmembrane Gi- coupled protein expressed both pre- and postsynaptically in brain regions associated with psychotic and cognitive functions, including the striatum, cortex, and hippocampus
- Amongst the mAChR subtypes (M1-M5), the unique brain expression profile of M4 mAChR, as well as its effects on neurotransmitter signaling, make it a compelling target for various psychiatric diseases
- Our hypothesis for activating M4 receptors is that the resultant reduction in acetylcholine (ACh) release can potentially correct the striatal hyperdopaminergic activity that has been linked to symptoms of psychosis
- The development of subtype-selective, potent M4 agonists provides therapeutic potential for treatment of psychosis symptoms observed in both schizophrenia and neurodegenerative conditions, such as Alzheimer's disease
Figure 1. MOA hypothesis.
M4 mAChR | ACh release from | Striatal DA | |
cholinergic | Psychosis ↓ | ||
activation ↑ | release ↓ | ||
interneurons ↓ |
RESULTS
OBJECTIVE & STUDY DESIGN
- To investigate the effects of systemic subcutaneous (SC) administration of 2 different test compounds (TC) - a full (CV-0000042) compared with a partial (CV-0000071) M4 receptor agonist - at 2 doses each (Table 1) on amphetamine-induced brain activity in anesthetized Sprague-Dawley rats (Crl:CD(SD)) using relative cerebral blood volume (rCBV) functional MRI (fMRI) readout
Figure 2. Schematic of design for rCBV fMRI study.
Contrast | TC or | Amp (1mg/kg) or | |||
agent | veh (SC) | veh (SC) | |||
t (min) -30 | -20 | 0 | 30 | 75 | Plasma (PK) |
Arterial blood gas | MRI acquisition | Arterial blood gas | |||
(pre-imaging) | (post-imaging) | ||||
METHODS: Dosing and fMRI Protocol
-
Adult male, cannulated, ventilated Sprague-Dawley (Crl:CD(SD)) rats (body weight, 345
± 20 g) were imaged under medetomidine-isoflurane anesthesia. For a total duration of
1.75 hours, fMRI scans were acquired using a Bruker 7T MRI system (Bruker, Billerica, MA, USA). Physiological monitoring included pre- and post-imaging arterial blood gas and pH measurements, as well as continuous heart rate recording. Relative cerebral blood volume (rCBV) data were collected using high resolution T2*-weighted gradient- echo sequence (FLASH) with iron oxide contrast agent (ferumoxytol; intravenous). Test compounds were dosed 30 minutes prior to the amphetamine (Amp) challenge, and rCBV changes followed uninterrupted for 45 min post Amp injection. Terminal plasma samples were collected for PK analysis. All animal experiments were conducted in accordance with institutions' Institutional Animal Care and Use Committee or equivalent ethics committee(s)
Table 1. Experimental Groups for fMRI Study
Group | Treatment compound | Dose | Dosing route | Challenge compound | Group size |
1 | Vehicle (5% DMSO/5% Solutol/ | 1 ml/kg | SC | Vehicle (Saline); SC | 12 |
90% sterile water) | |||||
2 | Vehicle (5% DMSO/5% Solutol/ | 1 ml/kg | SC | Amphetamine; 1 mg/kg, SC | 12 |
90% sterile water) | |||||
3 | CV-0000042 | 0.032 mg/kg | SC | Amphetamine; 1 mg/kg, SC | 12 |
4 | CV-0000042 | 0.32 mg/kg | SC | Amphetamine; 1 mg/kg, SC | 12 |
5 | CV-0000071 | 0.032 mg/kg | SC | Amphetamine; 1 mg/kg, SC | 12 |
6 | CV-0000071 | 0.32 mg/kg | SC | Amphetamine; 1 mg/kg, SC | 12 |
DMSO, dimethyl sulfoxide; SC, subcutaneous.
1Cerevel Therapeutics, Cambridge, MA, USA;
2Charles River Discovery Services, Kuopio, Finland
Presenting Author: Sophia Bardehle, Sophia.Bardehle@cerevel.com
CONCLUSIONS
Amphetamine (1 mg/kg; SC) induced highly significant increase
PLASMA PK DATA
Figure 3. Plasma | 125 | CV-0000042 0.032 mg/kg | ||||||||||||
concentrations in | ||||||||||||||
100 | CV-0000042 0.32 mg/kg | |||||||||||||
terminal plasma | [ng/ml] | |||||||||||||
CV-0000071 0.032 mg/kg | ||||||||||||||
samples collected | 75 | |||||||||||||
CV-0000071 0.32 mg/kg | ||||||||||||||
at the end of the | ||||||||||||||
Conc | 50 | |||||||||||||
rCBV MRI scan, | ||||||||||||||
75-80 min after | 25 | |||||||||||||
CV-0000071 REDUCED AMP-INDUCED rCBV RESPONSE IN A DOSE-DEPENDENT MANNER IN THE CORTEX AND STRIATUM
Figure 5. CV-0000071: Group rCBV signal time series from the low- and high-dose group in the medial | Figure 6. CV-0000071: Group rCBV area under the curve | |
prefrontal cortex (A) and caudate putamen (B). | (AUC) values of the 45-minfollow-up period after Amp | |
A | B | injection from all brain regions for CV-0000071 treatment |
groups. |
in rCBV peaking at approximately 15 minutes post injection across multiple brain areas, with the strongest effects observed in the striatum (25%) and medial prefrontal cortex (35%)
CV-0000071(partial agonist): Test compound (TC) effect aloneinduced a transient, significant decrease of rCBV response in the high-dose (0.32 mg/kg) group. Amphetamine-induced increase in CBV response was significantly reduced in a dose-
dosing. | 0 | ||||||||||||||||||
Table 2. PK Profile of CV-0000042 and CV-0000071 After Acute SC | |||||||||||||||||||
Dosing | |||||||||||||||||||
cu,p | cu,b | Change in | |||||||||||||||||
Compound | Dose (mg/kg) | (nM) | (nM) | cAMP, % | |||||||||||||||
CV-0000042 | 0.032 | 4.07 | 4.71 | 12 | |||||||||||||||
CV-0000042 | 0.32 | 35.52 | 41.2 | 58 | |||||||||||||||
CV-0000071 | 0.032 | 3.65 | 4.85 | 15 | |||||||||||||||
CV-0000071 | 0.32 | 34.78 | 46.26 | 63 |
rCBV, %
Veh-Amp, n=12 | Veh-Veh, n=12 |
CV-0000071 (0.032 mg/kg), n=12 | CV-0000071 (0.32 |
Dosing, SC | P<0.05, Veh-Amp |
P<0.01, Veh-Amp vs CV-0000071 (0.032 mg/kg) | P<0.01, Veh-Amp |
rCBV, %
mg/kg), n=12
vs CV-0000071 (0.032 mg/kg) vs CV-0000071 (0.32 mg/kg)
Veh-Veh
Veh-Amp
CV-0000071 0.032mg/kg - Amp
CV-0000071 0.32 mg/kg - Amp
Veh-Veh, n=12 | |||
Veh-Amp, n=12 | |||
CV-0000071 (0.032 mg/kg), n=12 | CV-0000071 (0.32 mg/kg), n=12 | ||
Dosing, SC | P<0.01, Veh-Amp vs CV-0000071 | (0.32 mg/kg) | |
P<0.01, Veh-Amp vs CV-0000071 (0.032 mg/kg) | P<0.05, Veh-Amp vs CV-0000071 | (0.032 mg/kg) | |
dependent manner in all major brain areas (mPFC and CPu shown) and sustained during the 45-minfollow-up
CV-0000042 (full agonist): TC effect aloneresulted in rapid, sustained decrease in rCBV response in the high-dosegroup (0.32 mg/kg). The lower dose (0.032 mg/kg) showed rCBV decrease of lower magnitude. Amphetamine-inducedincrease in
REPRESENTATIVE rCBV MRI MAPS
Figure 4. Representative rCBV maps showing brain activity of individual animals in Veh-Veh,Veh-Amp,CV-0000042 (0.032 or
0.32 mg/kg) - Amp, and CV-0000071 (0.032 or 0.32 mg/kg) - Amp groups.
Data are presented as mean ± SEM. Statistical analysis performed using point-wiseone-way ANOVA; dashed lines, P<0.05; solid lines, P<0.01. | Data are presented as mean ± SEM. Statistical analysis performed using two-way ANOVA with |
Holm-Sidak's multiple comparisons test against the control (Veh-Amp) group. | |
*P<0.05; **P<0.01; ***P<0.001; ****P<0.0001 |
CV-0000042 REDUCED BASELINE rCBV RESPONSE AND AMP-INDUCED RCBV RESPONSE IN THE CORTEX AND STRIATUM
rCBV was significantly reduced in both CV-0000042 dose groups in all major brain areas
The differential fMRI response profiles observed between compounds with different levels of M4 agonism suggest that there is an opportunity to dial in the most appropriate amount of intrinsic efficacy in a compound to match the desired downstream effect
ACKNOWLEDGMENTS: Thanks to the CRL Kuopio Team for the study execution; thanks to Scott Carrier and the DMPK group for support with the PK analysis. Thanks to the Cerevel chemistry team for support with compound logistics and advice on formulations.
Presented at the Society for Neuroscience (SfN)
November 13, 2022 • San Diego, CA, USA
Veh-Veh | Veh-Amp |
CV-0000042 (0.032 mg/kg SC) - Amp | CV-0000042 (0.32 mg/kg SC) - Amp |
CV-0000071 (0.032 mg/kg SC) - Amp | CV-0000071 (0.32 mg/kg SC) - Amp |
Color indicates high (red) or low (blue) median rCBV response over 45 minutes.
Figure 7. CV-0000042: Group rCBV signal time series from low-dose and high-dose groups in the medial prefrontal cortex (A) and caudate putamen (B).
AB
rCBV, % | rCBV, % | |
Veh-Amp, n=12 | Veh-Veh, n=12 | |||||||
Veh-Amp, n=12 | Veh-Veh, n=12 | CV-0000042 (0.032 mg/kg), n=12 | CV-0000042 (0.32 mg/kg), n=12 | |||||
CV-0000042 (0.032 mg/kg), n=12 | CV-0000042 (0.32 mg/kg), n=12 | Dosing, SC | P<0.05, Veh-Amp vs CV-0000042 | (0.032 mg/kg) | ||||
Dosing, SC | P<0.01, Veh-Amp vs CV-0000042 | (0.32 mg/kg) | P<0.01, Veh-Amp vs CV-0000042 | (0.32 mg/kg) | ||||
P<0.05, Veh-Amp vs CV-0000042 (0.032 mg/kg) | P<0.01, Veh-Amp vs CV-0000042 | (0.032 mg/kg) | ||||||
Data are presented as mean ± SEM. Statistical analysis performed using point-wise,one-way ANOVA; dashed lines, P<0.05; solid lines, P<0.01.
Figure 8. CV-0000042: Group rCBV area under the curve (AUC) values of the 45-minfollow-up period after Amp injection from all brain regions for CV-0000042 treatment groups.
Veh-Veh
Veh-Amp
CV-0000042 0.032mg/kg - Amp
CV-0000042 0.32 mg/kg - Amp
Data are presented as mean ± SEM. Statistical analysis performed using two-way ANOVA with Holm-Sidak's multiple comparisons test against the control (Veh-Amp) group.
*P<0.05.
22-CVE-7094_Poster_M4_SfN2022_M2-2.pdf 1 | 11/8/22 11:59 AM |
Attachments
- Original Link
- Original Document
- Permalink
Disclaimer
Cerevel Therapeutics Holdings Inc. published this content on 13 November 2022 and is solely responsible for the information contained therein. Distributed by Public, unedited and unaltered, on 13 November 2022 20:11:04 UTC.