Project description:MicroRNA regulates protein expression of cells by repressing translation of specific target messenger transcripts. Loss of the neuron specific microRNA miR-128 in Dopamine D1-receptor expressing neurons in the murine striatum (D1-MSNs) lead to increased neuronal excitability, locomotor hyperactivity and fatal epilepsy. To examine expression changes in the absence of miR-128 in D1-MSNs, we used mice expressing EGFP-tagged ribosomes in D1-MSNs with either D1-MSN-specific homozygous deletion of miR-128-2 locus or no deletion. Transcripts co-immunoprecipitated with tagged ribosomes were analyzed by microarray.
Project description:MicroRNA regulates protein expression of cells by repressing translation of specific target messenger transcripts. Loss of the neuron specific microRNA miR-128 in Dopamine D1-receptor expressing neurons in the murine striatum (D1-MSNs) lead to increased neuronal excitability, locomotor hyperactivity and fatal epilepsy. To examine expression changes in the absence of miR-128 in D1-MSNs, we used mice expressing EGFP-tagged ribosomes in D1-MSNs with either D1-MSN-specific homozygous deletion of miR-128-2 locus or no deletion. Transcripts co-immunoprecipitated with tagged ribosomes were analyzed by microarray. 9 mutant animals ( D1-MSN-tagged ribosome; D1-MSN specific miR-128-2 homozygous deletion) and 7 age matched littermate control animals (D1-MSN-tagged ribosome only).
Project description:Nair2015 - Interaction between
neuromodulators via GPCRs - Effect on cAMP/PKA signaling (D1
Neuron)
This model is described in the article:
Sensing Positive versus
Negative Reward Signals through Adenylyl Cyclase-Coupled GPCRs
in Direct and Indirect Pathway Striatal Medium Spiny
Neurons.
Nair AG, Gutierrez-Arenas O,
Eriksson O, Vincent P, Hellgren Kotaleski J.
J. Neurosci. 2015 Oct; 35(41):
14017-14030
Abstract:
Transient changes in striatal dopamine (DA) concentration
are considered to encode a reward prediction error (RPE) in
reinforcement learning tasks. Often, a phasic DA change occurs
concomitantly with a dip in striatal acetylcholine (ACh),
whereas other neuromodulators, such as adenosine (Adn), change
slowly. There are abundant adenylyl cyclase (AC) coupled GPCRs
for these neuromodulators in striatal medium spiny neurons
(MSNs), which play important roles in plasticity. However,
little is known about the interaction between these
neuromodulators via GPCRs. The interaction between these
transient neuromodulator changes and the effect on cAMP/PKA
signaling via Golf- and Gi/o-coupled GPCR are studied here
using quantitative kinetic modeling. The simulations suggest
that, under basal conditions, cAMP/PKA signaling could be
significantly inhibited in D1R+ MSNs via ACh/M4R/Gi/o and an
ACh dip is required to gate a subset of D1R/Golf-dependent PKA
activation. Furthermore, the interaction between ACh dip and DA
peak, via D1R and M4R, is synergistic. In a similar fashion,
PKA signaling in D2+ MSNs is under basal inhibition via
D2R/Gi/o and a DA dip leads to a PKA increase by disinhibiting
A2aR/Golf, but D2+ MSNs could also respond to the DA peak via
other intracellular pathways. This study highlights the
similarity between the two types of MSNs in terms of high basal
AC inhibition by Gi/o and the importance of interactions
between Gi/o and Golf signaling, but at the same time predicts
differences between them with regard to the sign of RPE
responsible for PKA activation.Dopamine transients are
considered to carry reward-related signal in reinforcement
learning. An increase in dopamine concentration is associated
with an unexpected reward or salient stimuli, whereas a
decrease is produced by omission of an expected reward. Often
dopamine transients are accompanied by other neuromodulatory
signals, such as acetylcholine and adenosine. We highlight the
importance of interaction between acetylcholine, dopamine, and
adenosine signals via adenylyl-cyclase coupled GPCRs in shaping
the dopamine-dependent cAMP/PKA signaling in striatal neurons.
Specifically, a dopamine peak and an acetylcholine dip must
interact, via D1 and M4 receptor, and a dopamine dip must
interact with adenosine tone, via D2 and A2a receptor, in
direct and indirect pathway neurons, respectively, to have any
significant downstream PKA activation.
This model is hosted on
BioModels Database
and identified by:
BIOMD0000000635.
To cite BioModels Database, please use:
BioModels Database:
An enhanced, curated and annotated resource for published
quantitative kinetic models.
To the extent possible under law, all copyright and related or
neighbouring rights to this encoded model have been dedicated to
the public domain worldwide. Please refer to
CC0
Public Domain Dedication for more information.
Project description:Nair2015 - Interaction between
neuromodulators via GPCRs - Effect on cAMP/PKA signaling (D2
Neuron)
This model is described in the article:
Sensing Positive versus
Negative Reward Signals through Adenylyl Cyclase-Coupled GPCRs
in Direct and Indirect Pathway Striatal Medium Spiny
Neurons.
Nair AG, Gutierrez-Arenas O,
Eriksson O, Vincent P, Hellgren Kotaleski J.
J. Neurosci. 2015 Oct; 35(41):
14017-14030
Abstract:
Transient changes in striatal dopamine (DA) concentration
are considered to encode a reward prediction error (RPE) in
reinforcement learning tasks. Often, a phasic DA change occurs
concomitantly with a dip in striatal acetylcholine (ACh),
whereas other neuromodulators, such as adenosine (Adn), change
slowly. There are abundant adenylyl cyclase (AC) coupled GPCRs
for these neuromodulators in striatal medium spiny neurons
(MSNs), which play important roles in plasticity. However,
little is known about the interaction between these
neuromodulators via GPCRs. The interaction between these
transient neuromodulator changes and the effect on cAMP/PKA
signaling via Golf- and Gi/o-coupled GPCR are studied here
using quantitative kinetic modeling. The simulations suggest
that, under basal conditions, cAMP/PKA signaling could be
significantly inhibited in D1R+ MSNs via ACh/M4R/Gi/o and an
ACh dip is required to gate a subset of D1R/Golf-dependent PKA
activation. Furthermore, the interaction between ACh dip and DA
peak, via D1R and M4R, is synergistic. In a similar fashion,
PKA signaling in D2+ MSNs is under basal inhibition via
D2R/Gi/o and a DA dip leads to a PKA increase by disinhibiting
A2aR/Golf, but D2+ MSNs could also respond to the DA peak via
other intracellular pathways. This study highlights the
similarity between the two types of MSNs in terms of high basal
AC inhibition by Gi/o and the importance of interactions
between Gi/o and Golf signaling, but at the same time predicts
differences between them with regard to the sign of RPE
responsible for PKA activation.Dopamine transients are
considered to carry reward-related signal in reinforcement
learning. An increase in dopamine concentration is associated
with an unexpected reward or salient stimuli, whereas a
decrease is produced by omission of an expected reward. Often
dopamine transients are accompanied by other neuromodulatory
signals, such as acetylcholine and adenosine. We highlight the
importance of interaction between acetylcholine, dopamine, and
adenosine signals via adenylyl-cyclase coupled GPCRs in shaping
the dopamine-dependent cAMP/PKA signaling in striatal neurons.
Specifically, a dopamine peak and an acetylcholine dip must
interact, via D1 and M4 receptor, and a dopamine dip must
interact with adenosine tone, via D2 and A2a receptor, in
direct and indirect pathway neurons, respectively, to have any
significant downstream PKA activation.
This model is hosted on
BioModels Database
and identified by:
BIOMD0000000636.
To cite BioModels Database, please use:
BioModels Database:
An enhanced, curated and annotated resource for published
quantitative kinetic models.
To the extent possible under law, all copyright and related or
neighbouring rights to this encoded model have been dedicated to
the public domain worldwide. Please refer to
CC0
Public Domain Dedication for more information.
Project description:About half of all human and mouse miRNA genes are located within introns of protein-coding genes. Despite this, little is known about functional interactions between miRNAs and their host genes. The intronic miRNA miR-128 regulates neuronal excitability and controls dendrite outgrowth of projection neurons during development of the mouse cerebral cortex. Its host genes R3hdm1 and Arpp21 encode highly conserved, putative RNA-binding proteins. Here we use iCLIP to describe the RNA-binding activity of ARPP21, which recognizes uridine-rich sequences with exquisite sensitivity for 3UTRs. Surprisingly, ARPP21 antagonizes miR-128 activity by co-regulating a subset of miR-128 target mRNAs enriched for neurodevelopmental functions. In contrast to miR-128, we show that ARPP21 acts as a positive post-transcriptional regulator, at least in part through interaction with the eukaryotic translation initiation complex eIF4F. This molecular antagonism is also reflected in inverse activities during dendritogenesis: miR-128 overexpression or knockdown of ARPP21 reduces dendritic complexity; ectopic ARPP21 leads to an increase. The regulatory interaction between ARPP21 and miR-128 is a unique example of convergent function by two products of a single gene.
Project description:The striatum is the main input structure of the basal ganglia, receiving information from the cortex and the thalamus and consisting of D1- and D2- medium spiny neurons (MSNs). D1-MSNs and D2-MSNs are essential for motor control and cognitive behaviors and have implications in Parkinson’s Disease. In the present study, we demonstrated that Sp9 positive progenitors produced both D1-MSNs and D2-MSNs and that Sp9 expression was rapidly downregulated in postmitotic D1-MSNs. Furthermore, we found that sustained Sp9 expression in lateral ganglionic eminence (LGE) progenitor cells and their descendants led to promoting D2-MSNs identity and repressing D1-MSNs identity during striatal development. As a result, sustained Sp9 expression resulted in an imbalance between D1-MSNs and D2-MSNs in the mouse striatum. In addition, the fate-changed D2 like-MSNs survived normally in adulthood. Taken together, our finding supported that Sp9 was sufficient to promote D2-MSNs identity and repress D1-MSNs identity, and Sp9 was a negative regulator of D1-MSNs fate. The striatum is the main input structure of the basal ganglia, receiving information from the cortex and the thalamus and consisting of D1- and D2- medium spiny neurons (MSNs). D1-MSNs and D2-MSNs are essential for motor control and cognitive behaviors and have implications in Parkinson’s Disease. In the present study, we demonstrated that Sp9 positive progenitors produced both D1-MSNs and D2-MSNs and that Sp9 expression was rapidly downregulated in postmitotic D1-MSNs. Furthermore, we found that sustained Sp9 expression in lateral ganglionic eminence (LGE) progenitor cells and their descendants led to promoting D2-MSNs identity and repressing D1-MSNs identity during striatal development. As a result, sustained Sp9 expression resulted in an imbalance between D1-MSNs and D2-MSNs in the mouse striatum. In addition, the fate-changed D2 like-MSNs survived normally in adulthood. Taken together, our finding supported that Sp9 was sufficient to promote D2-MSNs identity and repress D1-MSNs identity, and Sp9 was a negative regulator of D1-MSNs fate.
Project description:The striatum in the brain is involved in various behavioral functions, including reward, and disease processes, such as opioid use disorder (OUD). Further understanding of the role of striatal subregions in reward behaviors and their potential associations with OUD requires molecular identification of specific striatal cell types in human brain. The human striatum contains subregions based on different anatomical, functional, and physiological properties, with the dorsal striatum further divided into caudate and putamen. Both caudate and putamen are associated with alterations in reward processing, formation of habits, and development of negative affect states in OUD. Using single nuclei RNA-sequencing of human postmortem caudate and putamen, we identified canonical neuronal cell types in striatum (e.g., dopamine receptor 1 or 2 expressing neurons, D1 or D2) and less abundant subpopulations, including D1/D2 hybrid neurons and multiple classes of interneurons. By comparing unaffected subjects to subjects with OUD, we found neuronal-specific differences in pathways related to neurodegeneration, interferon response, and DNA damage. DNA damage markers were also elevated in striatal neurons of rhesus macaques following chronic opioid administration. We identified sex-dependent differences in the expression of stress-induced transcripts (e.g., FKBP5) among astrocytes and oligodendrocytes from female subjects with OUD. Thus, we describe striatal cell types and leverage these data to gain insights into molecular alterations in human striatum associated with opioid addiction.
Project description:Schizophrenia is a chronic mental illness that is among the world’s top twenty causes of years lost to disability according to the global burden of disease 2019 (10.1016/S0140-6736(20)30925-9). Positive symptoms, including hallucinations and delusions in schizophrenia, often improved with conventional antipsychotic medication, which exerts its therapeutic effects mainly by antagonizing the dopamine D2 receptors. Haloperidol was one of the first antipsychotics to be approved by the FDA, and it is since then widely used for the treatment of psychotic disorders including schizophrenia. Despite its high affinity for dopamine D2 receptors, it has been shown that haloperidol interacts with other receptors, such as dopamine D3 and D4 receptors, α-adrenergic receptor 1 and to some extent 5HT2A. Dopaminergic dysfunction is known for decades to be involved in the pathophysiology of schizophrenia, but only recently has the striatum been implicated in such devasting disorder. The dorsal striatum is a brain region involved in motor, cognitive and motivational functions, highly impacted by antipsychotic drugs. Particularly, it is well-recognized that chronic haloperidol administration has a tremendous impact on striatal synaptic plasticity, by changing the volume of dorsal striatum, the number of striatal neurons and the synaptic morphology, both in humans and rodents. Despite the overwhelming evidence correlating chronic haloperidol administration with striatum alterations, so far, the exact striatal synaptic mechanism by which haloperidol exerts its beneficial effects remains unclear. Although dopamine D2 receptor blockade can be achieved within hours after haloperidol administration, the onset of action is delayed by weeks. Thus, it is crucial to better understand the neuronal mechanism behind the delayed clinical effects of haloperidol to improve the treatment outcome. Using proteomic analysis and whole-cell patch-clamp recordings (Figure 1), we demonstrate for the first time a possible mechanism by which haloperidol may be contributing to its beneficial long-term therapeutic effect. Specifically, we demonstrate that modulation of D2-MSNs by chronic haloperidol administration leads to a slow remodeling of D1-neurons that may be responsible for its positive therapeutic effects.
Project description:The striatum is the main input structure of the basal ganglia, receiving information from the cortex and the thalamus and consisting of D1- and D2- medium spiny neurons (MSNs). D1-MSNs and D2-MSNs are essential for motor control and cognitive behaviors and have implications in Parkinson’s Disease. In the present study, we demonstrated that Sp9 positive progenitors produced both D1-MSNs and D2-MSNs and that Sp9 expression was rapidly downregulated in postmitotic D1-MSNs. Furthermore, we found that sustained Sp9 expression in lateral ganglionic eminence (LGE) progenitor cells and their descendants led to promoting D2-MSNs identity and repressing D1-MSNs identity during striatal development. As a result, sustained Sp9 expression resulted in an imbalance between D1-MSNs and D2-MSNs in the mouse striatum. In addition, the fate-changed D2 like-MSNs survived normally in adulthood. Taken together, our finding supported that Sp9 was sufficient to promote D2-MSNs identity and repress D1-MSNs identity, and Sp9 was a negative regulator of D1-MSNs fate.
Project description:Yapo2017- cAMP/PKA signalling in D1 dopamine receptor expressing medium-spiny neurons
This model is described in the article:
Detection of phasic dopamine
by D1 and D2 striatal medium spiny neurons.
Yapo C, Nair AG, Clement L, Castro
LR, Hellgren Kotaleski J, Vincent P.
J. Physiol. (Lond.) 2017 Aug; :
Abstract:
The phasic release of dopamine in the striatum determines
various aspects of reward and action selection, but the
dynamics of dopamine effect on intracellular signalling remains
poorly understood. We used genetically-encoded FRET biosensors
in striatal brain slices to quantify the effect of transient
dopamine on cAMP or PKA-dependent phosphorylation level, and
computational modelling to further explore the dynamics of this
signalling pathway. Medium-sized spiny neurons (MSNs), which
express either D1 or D2 dopamine receptors, responded to
dopamine by an increase or a decrease in cAMP, respectively.
Transient dopamine showed similar sub-micromolar efficacies on
cAMP in both D1 and D2 MSNs, thus challenging the commonly
accepted notion that dopamine efficacy is much higher on D2
than on D1 receptors. However, in D2 MSNs, the large decrease
in cAMP level triggered by transient dopamine did not translate
in a decrease in PKA-dependent phosphorylation level, owing to
the efficient inhibition of Protein Phosphatase 1 by DARPP-32.
Simulations further suggested that D2 MSNs can also operate in
a "tone-sensing" mode, allowing them to detect transient dips
in basal dopamine. Overall, our results show that D2 MSNs may
sense much more complex patterns of dopamine than previously
thought. This article is protected by copyright. All rights
reserved.
This model is hosted on
BioModels Database
and identified by:
MODEL1701170000.
To cite BioModels Database, please use:
BioModels Database:
An enhanced, curated and annotated resource for published
quantitative kinetic models.
To the extent possible under law, all copyright and related or
neighbouring rights to this encoded model have been dedicated to
the public domain worldwide. Please refer to
CC0
Public Domain Dedication for more information.