Download Developmental regulation of Medium Spiny Neuron dendritic

Developmental regulation
of Medium Spiny Neuron
dendritic arborization
Lorene M. Lanier
Department of Neuroscience
Diversity in dendritic arbors
Pyramindal
http://youtu.be/_tQPCa6wX84
Purkinje
http://youtu.be/Q4uh2r1djWw
Medium Spiny
Diversity in dendritic arbors
Pyramindal
Purkinje
Medium Spiny
•  Dendrites “sum-up” synaptic potentials, determining whether there
will be an action potential in the axon
•  Shape and size of the dendritic arbor determines
•  Number of synapses
•  position of synapses with respect to the soma
•  May also affect the probability of being “found” by an axon
during development
•  Why do different types of neurons have such
different dendritic arbors???
•  How does a neuron “know” what it’s shape
should be?
•  How is this affected by the environment?
The Striatum
The striatum (caudate + putamen) receives input
from the SNc and almost all cortical areas
glutamate
dopamine
Nuclei of the basal ganglia
D1
Caudate & Putamen
Medium spiny neurons (MSNs)
•  GABAergic
•  dopamine receptors
•  D1 coupled to Gs
•  D2 coupled to Gi
•  Low basal activity
D1
D2
D2
Globus pallidus
Striatopallidal pathway
D1
Striatonigral
pathway
Medium spiny neurons (MSNs)
§ 
>90% of neurons in striatum are MSNs
§ 
Dendritic spine heads are the major site of excitatory
synapses
Dendritic spine necks are the site of dopamine synapses
Integrate glutamate and dopamine inputs
Release GABA (inhibitory signal)
Modulate movement
Play a major role in motivation and addiction
One of the first cell types affected Huntington's disease
Aberrant function in Parkinson's Disease due to death of
dopamine expressing neurons
Many in vivo models for MSN plasticity
§ 
§ 
§ 
§ 
§ 
§ 
§ 
§ 
Kotter Prog Neurobiol 1994
MSN
glutamate synapse
dopamine synapse
What are the molecular mechanisms
regulating MSN development and
plasticity?
need an in vitro model
The ganglionic eminence (GE)
•  MSNs ion the striatum and nucleus
accumbens are born in the LGE
•  Interneurons in the cortex are born in
the MGE and undergo tangential
migration
•  Neurons in the globus pallidus are
born in the MGE
Dlx1/2
Mash1
expressing
precursor
Ctip2
migrating
MSN
FoxP1
DARPP32
mature
MSN
Medium Spiny Neurons
In Vivo
J Comp Neurology 1989
In Vitro
Segal et al. (2003) Eur. J. Neurosci 17: 2537
Medium spiny neurons (MSNs)
§ 
>90% of neurons in striatum are MSNs
§ 
Integrate glutamate and dopamine in same
spine
Release GABA (inhibitory signal)
Modulate movement
Play a major role in motivation and addiction
One of the first cell types affected Huntington's
disease
Aberrant function in Parkinson's Disease due to
death of dopamine expressing neurons
Many in vivo models for MSN plasticity
§ 
§ 
§ 
§ 
§ 
§ 
Kotter Prog Neurobiol 1994
MSN
glutamate synapse
dopamine synapse
*+)(,!#& -(+)&#$ (. /!+)(01%!&1!2 3($4 562 ,,4 7869:78;82 7<<9
! =!>!)#"%(& (. *+)(,!#& /!+)(01%!&1! ?(1%!"%!0
!"#$%&'"( ") *+(*#'&', -.'(+- '( ,/0&/#+* -&#'%&%0 (+/#"(*+.+(*- "( +1,'&%&"#2 %))+#+(& %,&'3'&2
4+(%5+$ 6+7%08 9%#*% :#++(;+#7+# !"# <*/%#* ="#>"&'%(
$%&!'()%"( *+ ,%-'*./*0*123 45% 6%/7)!"" 8"9(/(-(%3 :%5*;*( <=>??3 89'!%0
!"#$%&'(@ A*"+*A!0 )/A'*9A*&%3 A*'(%B3 CDEF93 GHIH3 GJD3 '*#%"(9
?;-&#%,&
@5+ #"0+ ") %))+#+(& '((+#3%&'"( '( &5+ )"#$%&'"( ") *+(*#'&', -.'(+- A%- -&/*'+* '( ,/0&/#+* #%& -&#'%&/$B @5+ -&#'%&/$ '- % /('C/+
-&#/,&/#+ '( &5%& '& ,"(&%'(- 5'7502 -.'(2 :?D?+#7', .#"E+,&'"( (+/#"(-8 A'&5 (" >("A( 0",%0 +1,'&%&'"(B :#"A( %0"(+ '( ,/0&/#+8 -&#'%&%0
(+/#"(- *'* ("& +1.#+-- -."(&%(+"/- (+&A"#> %,&'3'&2 %(* A+#+ 3'#&/%002 *+3"'* ") *+(*#'&', -.'(+-B ?**'(7 :!FG+1.#+--'(7 $"/-+
,"#&',%0 (+/#"(- &" &5+ -&#'%&%0 ,/0&/#+ ,%/-+* &5+ %..+%#%(,+ ") -."(&%(+"/- %(* +3">+* +1,'&%&"#2 -2(%.&', ,/##+(&- '( &5+ -&#'%&%0
(+/#"(- %(* % HIG)"0* '(,#+%-+ '( &5+ *+(-'&2 ") -.'(+- "( &5+'# *+(*#'&+-B @5'- +))+,& A%- ;0",>+* ;2 % ,"(&'(/"/- .#+-+(,+ ") @@J '(
&5+ 7#"A&5 $+*'/$8 A5'0+ #+$"3%0 ") &5+ *#/7 ,%/-+* % #%.'* %..+%#%(,+ ") -.'(+-B <1."-/#+ &" 70/&%$%&+8 "# &5+ .#+-+(,+ ") ,"#&+1G
,"(*'&'"(+* $+*'/$ *'* ("& $'$', &5+ +))+,& ") ,"#&',%0 (+/#"(- "( )"#$%&'"( ") -.'(+- '( &5+ -&#'%&%0 (+/#"(-B ?0-"8 &5+ ,"#&',%0
'((+#3%&'"( *'* ("& ,%/-+ % -+0+,&'3+ +(5%(,+$+(& ") -/#3'3%0 ") -.+,'K, -/;&2.+- ") -.'(2 -&#'%&%0 (+/#"(-B @5+-+ +1.+#'$+(&*+$"(-&#%&+ &5%& +1,'&%&"#2 %))+#+(&- %#+ (+,+--%#2 )"# &5+ )"#$%&'"( ") *+(*#'&', -.'(+- '( -&#'%&%0 (+/#"(-B
L(&#"*/,&'"(
Our co-culture method
NC
GE
§  Start with E16 neocortex &
ganglionic eminence
§  Dissect
§  Dissociate
§  Co-plate 3 parts cortex:2 parts GE
§  Goals:
§  in vivo-like morphology
§  reproducibility
Penrod et al. (2011) J. Neurosci. Methods
MSNs grown in co-culture have more
complex morphologies
MSNs grown in co-culture have more
complex morphologies
Co-culture yields MSNs with a high density of
“mature” dendritic spines
Electrophysiological properties of MSNs in
co-culture
Medium Spiny Neurons
In Vivo
What next?
In Vitro
MSNs dendrite complexity increases
during development
13-19 DIV
MSNs dendritic spine density increases
during development
Medium spiny neurons (MSNs)
§ 
>90% of neurons in striatum are MSNs
§ 
Integrate glutamate and dopamine in same
spine
Release GABA (inhibitory signal)
Modulate movement
Play a major role in motivation and addiction
One of the first cell types affected Huntington's
disease
Aberrant function in Parkinson's Disease due to
death of dopamine expressing neurons
Many in vivo models for MSN plasticity
§ 
§ 
§ 
§ 
§ 
§ 
Kotter Prog Neurobiol 1994
MSN
glutamate synapse
dopamine synapse
Loss of dopamine leads to the death or mature MSNs,
but does dopamine play a role in development?
Dopamine enhances arborization, but not
the initial formation of MSN dendrites
Dopamine increases the length and number
of dendrite branches
- DA
+DA
- DA
+DA
Dopamine increases the number of
dendritic spines
- DA
+DA
Metabotropic receptors couple with different types of
trimeric G proteins
DopaminebindstoGProteincoupledreceptors
Quinprole
SKF82958
dopamine
D2
D1
Gi
Gs
adenylyl
cyclase
ATP
cAMP
ProteinKinaseA
D1 and D2 Receptor agonists
cannot replicate the effects of dopamine
Metabotropic receptors couple with different types of
trimeric G proteins
Whatifdopaminedoesn’tbindD1orD2,butinstead...
dopamine
D2
D1
D1 D2
Gq
Gi
Gs
adenylyl
cyclase
ATP
cAMP
ProteinKinaseA
phospho-
lipaseC
PIP2
DAG&IP3
ProteinKinaseC
Ca+2
CaMK
??
IP3 receptor
on ER
A PLC antagonist attenuates the effects of dopamine
DesignerReceptorExclusivelyAcCvatedbyDesignerDrugs
Clozapine-N-oxide(CNO)
•  Transfect DREADD-mCherry plasmid into
neurons
•  Add CNO to activate receptor
Gq
•  Overstimulation of this DREADD causes
seizures and death in vivo
phospho-
lipaseC
PIP2
•  Can we find [CNO] that is “just right” in
vitro?
•  too much-à transfected cells die
•  too littleà no effect on MSN growth
DAG&IP3
IP3 receptor on ER
ProteinKinaseC
CaMK
Ca+2
AcCvaConofDREADD-GqenhancesMSN
dendriCcbranching
MSN dendritic arborization:
•  requires input from cortical neurons
•  Dopamine enhances MSN dendritic arborization
•  D1 and D2 specific agonists alone or in combination do not mimic the
effect of dopamine
•  The effect of dopamine requires PLC activity
•  DREADD Gq activation of PLC mimics the effect of dopamine
•  These results are consistent with dopamine acting either via:
•  D1/D2 heteromer coupled to Gq
OR
•  D1 – D2 “synergy” that requires Gq
Metabotropic receptors couple with different types of
trimeric G proteins
Whatifdopaminedoesn’tbindD1orD2,butinstead...
SKF83959
dopamine
D1 D2
D2
D1
Gq
Gi
Gs
2P2A
adenylyl
cyclase
ATP
cAMP
ProteinKinaseA
U73122
phospho-
lipaseC
PIP2
DAG&IP3
ProteinKinaseC
Ca+2
CaMK
??
2APB
IP3 receptor
on ER
Lanier Lab
Rachel Penrod-Martin
Justin Campagna
Cassie Baumen
Daniel Boudani
Cole Davis
Mason Fellmeth
Emily Larson
Lauren Madden
Neema Moin Afshar
Lauren Pelkey
Luke Remme
Daniel Tam
Jordan Treder
Funding
NINDS
NIDA
AHC Seed Grant
MMF