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Cognitive Impairment Induced by Delta9-tetrahydrocannabinol Occurs through Heteromers between Cannabinoid CB1 and Serotonin 5-HT2A Receptors.

Viñals X, Moreno E, Lanfumey L, Cordomí A, Pastor A, de La Torre R, Gasperini P, Navarro G, Howell LA, Pardo L, Lluís C, Canela EI, McCormick PJ, Maldonado R, Robledo P - PLoS Biol. (2015)

Bottom Line: For this reason, there is a tremendous medical interest in harnessing the beneficial effects of THC.We found that specific effects of THC such as memory deficits, anxiolytic-like effects, and social interaction are under the control of 5-HT2AR, but its acute hypolocomotor, hypothermic, anxiogenic, and antinociceptive effects are not.CB1R-5-HT2AR heteromers are thus good targets to dissociate the cognitive deficits induced by THC from its beneficial antinociceptive properties.

View Article: PubMed Central - PubMed

Affiliation: Neuropharmacology Laboratory, University Pompeu Fabra, Barcelona, Spain.

ABSTRACT
Activation of cannabinoid CB1 receptors (CB1R) by delta9-tetrahydrocannabinol (THC) produces a variety of negative effects with major consequences in cannabis users that constitute important drawbacks for the use of cannabinoids as therapeutic agents. For this reason, there is a tremendous medical interest in harnessing the beneficial effects of THC. Behavioral studies carried out in mice lacking 5-HT2A receptors (5-HT2AR) revealed a remarkable 5-HT2AR-dependent dissociation in the beneficial antinociceptive effects of THC and its detrimental amnesic properties. We found that specific effects of THC such as memory deficits, anxiolytic-like effects, and social interaction are under the control of 5-HT2AR, but its acute hypolocomotor, hypothermic, anxiogenic, and antinociceptive effects are not. In biochemical studies, we show that CB1R and 5-HT2AR form heteromers that are expressed and functionally active in specific brain regions involved in memory impairment. Remarkably, our functional data shows that costimulation of both receptors by agonists reduces cell signaling, antagonist binding to one receptor blocks signaling of the interacting receptor, and heteromer formation leads to a switch in G-protein coupling for 5-HT2AR from Gq to Gi proteins. Synthetic peptides with the sequence of transmembrane helices 5 and 6 of CB1R, fused to a cell-penetrating peptide, were able to disrupt receptor heteromerization in vivo, leading to a selective abrogation of memory impairments caused by exposure to THC. These data reveal a novel molecular mechanism for the functional interaction between CB1R and 5-HT2AR mediating cognitive impairment. CB1R-5-HT2AR heteromers are thus good targets to dissociate the cognitive deficits induced by THC from its beneficial antinociceptive properties.

No MeSH data available.


Related in: MedlinePlus

Prevention of THC-induced amnesic and anxiolytic-like effects by pharmacological blockade of 5-HT2AR or by CB1R-5-HT2AR heteromer disruption with TM interference peptides.The amnesic effects of THC (3 mg/kg) observed in C57BL/6J mice in the novel object recognition test were abrogated by pretreatment with the 5-HT2AR antagonist, MDL 100,907 (0.01 mg/kg) (A) and by pretreatment with TM 5 and TM 6, but not TM 7, interference peptides (0.2 μg/ 2μl ICV) (B) (n = 5–9). The anxiolytic effects of THC (0.3 mg/kg) observed in the elevated plus maze in C57BL/6J mice were blocked by pretreatment with the 5-HT2AR antagonist, MDL 100,907 (0.01 mg/kg) (C) and by pretreatment with TM 5 and TM 6, but not TM 7, interference peptides (0.2 μg/ 2μl ICV) (D) (n = 4–11). The data represent mean + SEM. * p < 0.05, ** p < 0.01, *** p < 0.001 versus vehicle, # p < 0.05 versus THC-treated mice. In (E), PLA performed in hippocampal CA3, striatal (caudate-putamen), and cortical (somatomotor layers 1, 2, and 3) slices from mice treated with VEH, TM 6, and TM 7 interference peptides (0.2 μg/ 2μl ICV). Confocal microscopy images (superimposed sections) are shown in which heteromers appear as green spots in VEH and TM 7-treated mice, but not in mice treated with TM 6 interference peptides. In all cases, cell nuclei were stained with DAPI (blue). Scale bars = 20 μm. In (F), the number of cells containing one or more green spots is expressed as the percentage of the total number of cells (blue nucleus) in the hippocampus, striatum, and cortex (top to bottom). Data (percentage of positive cells) are the mean ± SEM of counts in 8–12 different fields. *** p < 0.001 versus vehicle-treated mice. Pretreatment with TM 5, TM 6, or TM 7 peptides (0.2 μg/ 2μl ICV) had no significant effects on hypolocomotion (G), hypothermia (H), or analgesia (I) induced by THC (10 mg/kg) in C57BL/6J mice. The statistical analyses used and their corresponding F and p-values are shown in S1 Table.
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pbio.1002194.g010: Prevention of THC-induced amnesic and anxiolytic-like effects by pharmacological blockade of 5-HT2AR or by CB1R-5-HT2AR heteromer disruption with TM interference peptides.The amnesic effects of THC (3 mg/kg) observed in C57BL/6J mice in the novel object recognition test were abrogated by pretreatment with the 5-HT2AR antagonist, MDL 100,907 (0.01 mg/kg) (A) and by pretreatment with TM 5 and TM 6, but not TM 7, interference peptides (0.2 μg/ 2μl ICV) (B) (n = 5–9). The anxiolytic effects of THC (0.3 mg/kg) observed in the elevated plus maze in C57BL/6J mice were blocked by pretreatment with the 5-HT2AR antagonist, MDL 100,907 (0.01 mg/kg) (C) and by pretreatment with TM 5 and TM 6, but not TM 7, interference peptides (0.2 μg/ 2μl ICV) (D) (n = 4–11). The data represent mean + SEM. * p < 0.05, ** p < 0.01, *** p < 0.001 versus vehicle, # p < 0.05 versus THC-treated mice. In (E), PLA performed in hippocampal CA3, striatal (caudate-putamen), and cortical (somatomotor layers 1, 2, and 3) slices from mice treated with VEH, TM 6, and TM 7 interference peptides (0.2 μg/ 2μl ICV). Confocal microscopy images (superimposed sections) are shown in which heteromers appear as green spots in VEH and TM 7-treated mice, but not in mice treated with TM 6 interference peptides. In all cases, cell nuclei were stained with DAPI (blue). Scale bars = 20 μm. In (F), the number of cells containing one or more green spots is expressed as the percentage of the total number of cells (blue nucleus) in the hippocampus, striatum, and cortex (top to bottom). Data (percentage of positive cells) are the mean ± SEM of counts in 8–12 different fields. *** p < 0.001 versus vehicle-treated mice. Pretreatment with TM 5, TM 6, or TM 7 peptides (0.2 μg/ 2μl ICV) had no significant effects on hypolocomotion (G), hypothermia (H), or analgesia (I) induced by THC (10 mg/kg) in C57BL/6J mice. The statistical analyses used and their corresponding F and p-values are shown in S1 Table.

Mentions: In order to implicate the involvement of the heteromer in the behavioral effects of THC in vivo, we evaluated cross antagonism in WT mice. Thus, the effects of the 5-HT2AR antagonist MDL 100,907 on THC-induced memory impairments using the object recognition test and on its anxiolytic-like properties using the elevated plus maze were evaluated. THC (3 mg/kg) induced significant memory impairments in vehicle-treated animals, but not in mice pretreated with MDL 100,907 (0.01 mg/kg) (Fig 10A). We further confirmed that this effect was mediated by the heteromer since THC-induced memory impairments were not observed in WT animals previously treated with TM5 or TM6 peptides (0.2 μg/2 μl ICV) but were present in animals receiving the TM7 peptide (Fig 10B). Similarly, THC-induced anxiolytic-like effects were prevented by MDL 100,907 administration (Fig 10C) and by ICV infusion of TM5 and TM6 peptides, but not by TM7 (Fig 10D). Importantly, using PLA we were able to demonstrate that administration of TM5 and TM6, but not TM7, peptides was able to disrupt the heteromer in vivo. In hippocampal CA3, striatal (caudate-putamen) or cortical (somatomotor layers 1, 2, and 3) slices from mice treated with vehicle or TM7 peptide (0.2 μg/2μl ICV) heteromers appear as green spots, a staining not seen in mice treated with equivalent amounts of TM6 peptide (Fig 10E and 10F). These results demonstrate that CB1R-5-HT2AR heteromers are involved in the amnesic and anxiolytic-like behavior induced by THC.


Cognitive Impairment Induced by Delta9-tetrahydrocannabinol Occurs through Heteromers between Cannabinoid CB1 and Serotonin 5-HT2A Receptors.

Viñals X, Moreno E, Lanfumey L, Cordomí A, Pastor A, de La Torre R, Gasperini P, Navarro G, Howell LA, Pardo L, Lluís C, Canela EI, McCormick PJ, Maldonado R, Robledo P - PLoS Biol. (2015)

Prevention of THC-induced amnesic and anxiolytic-like effects by pharmacological blockade of 5-HT2AR or by CB1R-5-HT2AR heteromer disruption with TM interference peptides.The amnesic effects of THC (3 mg/kg) observed in C57BL/6J mice in the novel object recognition test were abrogated by pretreatment with the 5-HT2AR antagonist, MDL 100,907 (0.01 mg/kg) (A) and by pretreatment with TM 5 and TM 6, but not TM 7, interference peptides (0.2 μg/ 2μl ICV) (B) (n = 5–9). The anxiolytic effects of THC (0.3 mg/kg) observed in the elevated plus maze in C57BL/6J mice were blocked by pretreatment with the 5-HT2AR antagonist, MDL 100,907 (0.01 mg/kg) (C) and by pretreatment with TM 5 and TM 6, but not TM 7, interference peptides (0.2 μg/ 2μl ICV) (D) (n = 4–11). The data represent mean + SEM. * p < 0.05, ** p < 0.01, *** p < 0.001 versus vehicle, # p < 0.05 versus THC-treated mice. In (E), PLA performed in hippocampal CA3, striatal (caudate-putamen), and cortical (somatomotor layers 1, 2, and 3) slices from mice treated with VEH, TM 6, and TM 7 interference peptides (0.2 μg/ 2μl ICV). Confocal microscopy images (superimposed sections) are shown in which heteromers appear as green spots in VEH and TM 7-treated mice, but not in mice treated with TM 6 interference peptides. In all cases, cell nuclei were stained with DAPI (blue). Scale bars = 20 μm. In (F), the number of cells containing one or more green spots is expressed as the percentage of the total number of cells (blue nucleus) in the hippocampus, striatum, and cortex (top to bottom). Data (percentage of positive cells) are the mean ± SEM of counts in 8–12 different fields. *** p < 0.001 versus vehicle-treated mice. Pretreatment with TM 5, TM 6, or TM 7 peptides (0.2 μg/ 2μl ICV) had no significant effects on hypolocomotion (G), hypothermia (H), or analgesia (I) induced by THC (10 mg/kg) in C57BL/6J mice. The statistical analyses used and their corresponding F and p-values are shown in S1 Table.
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pbio.1002194.g010: Prevention of THC-induced amnesic and anxiolytic-like effects by pharmacological blockade of 5-HT2AR or by CB1R-5-HT2AR heteromer disruption with TM interference peptides.The amnesic effects of THC (3 mg/kg) observed in C57BL/6J mice in the novel object recognition test were abrogated by pretreatment with the 5-HT2AR antagonist, MDL 100,907 (0.01 mg/kg) (A) and by pretreatment with TM 5 and TM 6, but not TM 7, interference peptides (0.2 μg/ 2μl ICV) (B) (n = 5–9). The anxiolytic effects of THC (0.3 mg/kg) observed in the elevated plus maze in C57BL/6J mice were blocked by pretreatment with the 5-HT2AR antagonist, MDL 100,907 (0.01 mg/kg) (C) and by pretreatment with TM 5 and TM 6, but not TM 7, interference peptides (0.2 μg/ 2μl ICV) (D) (n = 4–11). The data represent mean + SEM. * p < 0.05, ** p < 0.01, *** p < 0.001 versus vehicle, # p < 0.05 versus THC-treated mice. In (E), PLA performed in hippocampal CA3, striatal (caudate-putamen), and cortical (somatomotor layers 1, 2, and 3) slices from mice treated with VEH, TM 6, and TM 7 interference peptides (0.2 μg/ 2μl ICV). Confocal microscopy images (superimposed sections) are shown in which heteromers appear as green spots in VEH and TM 7-treated mice, but not in mice treated with TM 6 interference peptides. In all cases, cell nuclei were stained with DAPI (blue). Scale bars = 20 μm. In (F), the number of cells containing one or more green spots is expressed as the percentage of the total number of cells (blue nucleus) in the hippocampus, striatum, and cortex (top to bottom). Data (percentage of positive cells) are the mean ± SEM of counts in 8–12 different fields. *** p < 0.001 versus vehicle-treated mice. Pretreatment with TM 5, TM 6, or TM 7 peptides (0.2 μg/ 2μl ICV) had no significant effects on hypolocomotion (G), hypothermia (H), or analgesia (I) induced by THC (10 mg/kg) in C57BL/6J mice. The statistical analyses used and their corresponding F and p-values are shown in S1 Table.
Mentions: In order to implicate the involvement of the heteromer in the behavioral effects of THC in vivo, we evaluated cross antagonism in WT mice. Thus, the effects of the 5-HT2AR antagonist MDL 100,907 on THC-induced memory impairments using the object recognition test and on its anxiolytic-like properties using the elevated plus maze were evaluated. THC (3 mg/kg) induced significant memory impairments in vehicle-treated animals, but not in mice pretreated with MDL 100,907 (0.01 mg/kg) (Fig 10A). We further confirmed that this effect was mediated by the heteromer since THC-induced memory impairments were not observed in WT animals previously treated with TM5 or TM6 peptides (0.2 μg/2 μl ICV) but were present in animals receiving the TM7 peptide (Fig 10B). Similarly, THC-induced anxiolytic-like effects were prevented by MDL 100,907 administration (Fig 10C) and by ICV infusion of TM5 and TM6 peptides, but not by TM7 (Fig 10D). Importantly, using PLA we were able to demonstrate that administration of TM5 and TM6, but not TM7, peptides was able to disrupt the heteromer in vivo. In hippocampal CA3, striatal (caudate-putamen) or cortical (somatomotor layers 1, 2, and 3) slices from mice treated with vehicle or TM7 peptide (0.2 μg/2μl ICV) heteromers appear as green spots, a staining not seen in mice treated with equivalent amounts of TM6 peptide (Fig 10E and 10F). These results demonstrate that CB1R-5-HT2AR heteromers are involved in the amnesic and anxiolytic-like behavior induced by THC.

Bottom Line: For this reason, there is a tremendous medical interest in harnessing the beneficial effects of THC.We found that specific effects of THC such as memory deficits, anxiolytic-like effects, and social interaction are under the control of 5-HT2AR, but its acute hypolocomotor, hypothermic, anxiogenic, and antinociceptive effects are not.CB1R-5-HT2AR heteromers are thus good targets to dissociate the cognitive deficits induced by THC from its beneficial antinociceptive properties.

View Article: PubMed Central - PubMed

Affiliation: Neuropharmacology Laboratory, University Pompeu Fabra, Barcelona, Spain.

ABSTRACT
Activation of cannabinoid CB1 receptors (CB1R) by delta9-tetrahydrocannabinol (THC) produces a variety of negative effects with major consequences in cannabis users that constitute important drawbacks for the use of cannabinoids as therapeutic agents. For this reason, there is a tremendous medical interest in harnessing the beneficial effects of THC. Behavioral studies carried out in mice lacking 5-HT2A receptors (5-HT2AR) revealed a remarkable 5-HT2AR-dependent dissociation in the beneficial antinociceptive effects of THC and its detrimental amnesic properties. We found that specific effects of THC such as memory deficits, anxiolytic-like effects, and social interaction are under the control of 5-HT2AR, but its acute hypolocomotor, hypothermic, anxiogenic, and antinociceptive effects are not. In biochemical studies, we show that CB1R and 5-HT2AR form heteromers that are expressed and functionally active in specific brain regions involved in memory impairment. Remarkably, our functional data shows that costimulation of both receptors by agonists reduces cell signaling, antagonist binding to one receptor blocks signaling of the interacting receptor, and heteromer formation leads to a switch in G-protein coupling for 5-HT2AR from Gq to Gi proteins. Synthetic peptides with the sequence of transmembrane helices 5 and 6 of CB1R, fused to a cell-penetrating peptide, were able to disrupt receptor heteromerization in vivo, leading to a selective abrogation of memory impairments caused by exposure to THC. These data reveal a novel molecular mechanism for the functional interaction between CB1R and 5-HT2AR mediating cognitive impairment. CB1R-5-HT2AR heteromers are thus good targets to dissociate the cognitive deficits induced by THC from its beneficial antinociceptive properties.

No MeSH data available.


Related in: MedlinePlus