Skip to main page content
Access keys NCBI Homepage MyNCBI Homepage Main Content Main Navigation
Filters applied. Clear all
. 2016 Aug 2;16(5):1391-1404.
doi: 10.1016/j.celrep.2016.06.071. Epub 2016 Jul 14.

Caudal Ganglionic Eminence Precursor Transplants Disperse and Integrate as Lineage-Specific Interneurons but Do Not Induce Cortical Plasticity

Affiliations
Free PMC article

Caudal Ganglionic Eminence Precursor Transplants Disperse and Integrate as Lineage-Specific Interneurons but Do Not Induce Cortical Plasticity

Phillip Larimer et al. Cell Rep. .
Free PMC article

Abstract

The maturation of inhibitory GABAergic cortical circuits regulates experience-dependent plasticity. We recently showed that the heterochronic transplantation of parvalbumin (PV) or somatostatin (SST) interneurons from the medial ganglionic eminence (MGE) reactivates ocular dominance plasticity (ODP) in the postnatal mouse visual cortex. Might other types of interneurons similarly induce cortical plasticity? Here, we establish that caudal ganglionic eminence (CGE)-derived interneurons, when transplanted into the visual cortex of neonatal mice, migrate extensively in the host brain and acquire laminar distribution, marker expression, electrophysiological properties, and visual response properties like those of host CGE interneurons. Although transplants from the anatomical CGE do induce ODP, we found that this plasticity reactivation is mediated by a small fraction of MGE-derived cells contained in the transplant. These findings demonstrate that transplanted CGE cells can successfully engraft into the postnatal mouse brain and confirm the unique role of MGE lineage neurons in the induction of ODP.

Keywords: VIP interneuron; caudal ganglionic eminence; critical period; medial ganglionic eminence; ocular dominance plasticity.

Figures

Figure 1
Figure 1. MGE and CGE Transplants Disperse Broadly in Neocortex and Demonstrate Laminar Distributions Consistent with their Lineages
(A) Anatomical positions of MGE and CGE in E13.5 Nkx2.1-Cre;R26-Ai14 mouse brain (tdTomato expression recapitulates Nkx2.1 expression pattern and is shown here to demonstrate the spatial extent of MGE lineage neurons but was not used to guide dissection). Scale bar: 500 μm. POA, preoptic area; HY, hypothalamus. (B) Cells were dissected from the MGE or CGE at E13.5 (a), dissociated, and transplanted into the visual cortex of P2–5 hosts. MGE (b) or CGE (c) transplant recipient brains were examined at 33–35DAT. (C–E) Coronal brain sections stained for GFP at 35DAT to detect cells from anatomically isolated MGE (R26-GDTA donors; C), anatomically isolated CGE (R26-GDTA donors; D), or genetically isolated CGE (PV-Cre;SST-Cre;R26-GDTA donors; E) transplants. Scale bar: 1 mm. (F) Dorsoventral dispersion in the host cortex at 35DAT of cells from anatomically isolated MGE (blue, n=5 mice), anatomically isolated CGE (magenta, n=5 mice), and genetically isolated CGE (red, n=4 mice) transplants. Error bars represent SEM. p=0.44 by Kruskal-Wallis test. (G–I) Mouse brain sections co-stained for GFP, Satb2, and Ctip2 to reveal lamination of cells from anatomically isolated MGE (G), anatomically isolated CGE (H), and genetically isolated CGE (I) transplants at 35DAT in the host visual cortex. Scale bar: 100 μm. (J) Proportion of cells from anatomically isolated MGE (n=5 mice), anatomically isolated CGE (n=3 mice), and genetically isolated CGE (n=3 mice) transplants found in each layer of the host visual cortex at 35DAT. Error bars represent SEM. Significance calculated using Bonferroni corrected t-tests.
Figure 2
Figure 2. PV and SST Neurons In CGE Transplants Are MGE-Derived
(A–G) Visual cortex coronal sections of CGE transplant recipients at 35DAT stained for GFP (A′–G′), CR (A,A′), CB (B,B′), NPY (C,C′), VIP (D,D′), RLN (E,E′), PV (F,F′) and SST (G,G′). Arrowheads identify double-labeled cells. Scale bar: 100 μm. (H) Percent of transplanted GFP+ neurons immunoreactive for subtype markers in A–G found in R26-GDTA MGE (n=3 mice), R26-GDTA CGE (n=5 mice), and PV-Cre;SST-Cre;R26-GDTA CGE (n=3 mice) recipients at 35DAT. Error bars represent SEM. Significance calculated using Bonferroni corrected t-tests. (I–J) GFP, tdTomato, PV, and SST staining at 35DAT illustrating the presence of Nkx2.1 lineage PV and SST interneurons in CGE transplants. Arrowheads identify triple-labeled cells. Scale bar: 100 μm. (K) Percent of transplanted PV and SST interneurons which express tdTomato in anatomically isolated CGE transplants. Error bars represent SEM (n=3 mice).
Figure 3
Figure 3. Heterochronically Transplanted Interneuron Precursors Develop Diverse Electrophysiological Phenotypes
(A) MGE and CGE cells from donor mice expressing GFP ubiquitously and tdTomato specifically in MGE lineage neurons (Nkx2.1-Cre;R26-Ai14;β-actin-GFP) or tdTomato exclusively in VIP neurons (VIP-Cre;R26-Ai14) were harvested at E13.5 and transplanted into visual cortex of P2–7 hosts. Intracellular recordings from slices prepared at ~35DAT evaluate intrinsic physiological properties of transplant-derived interneurons. IR-DIC video micrograph with overlaid fluorescence shows a CGE-derived neuron (GFP only) and an MGE-derived neuron (GFP+, tdTomato+). (B) Example voltage (center) and interspike interval (ISI) responses (top) from a FS (a) and a non-FS (b) MGE transplant-derived neurons, to hyperpolarizing and depolarizing current injections. (C) Example voltage (center) and ISI (top) responses of the electrophysiological phenotypes observed among transplant-derived CGE lineage neurons. (D) Example action potential (a) and firing response (b) to a 500 ms depolarizing current injection demonstrate definitions used for F–H. (E–H) Input resistance (E), AP width at half maximum (F), AP after hyperpolarization depth (G), and AP accommodation (H) for MGE transplant-derived (blue) FS (circles) and non-FS (triangles), and CGE transplant-derived (red for GFP+/tdTomato- neurons in dual transplants, orange for VIP-Cre expressing) interneurons. Cell type legend at right: CA, continuous adapting; CN, continuous non-adapting non-FS; CI, continuous irregular spiking; CF, continuous fast spiking; BA, burst-adapting; BN, burst nonadapting non-FS; S, stuttering; DA, delayed adapting; after Ascoli et al. 2008). Black symbols correspond to cells in figure B,Ca–d.
Figure 4
Figure 4. MGE Transplant-Derived Interneurons and Host Pyramidal Neurons Form Frequent Synaptic Connections
(A) Paired recordings from a transplanted MGE lineage fast-spiking interneuron (b, blue) and a host pyramidal neuron (brown) at 35DAT reveal postsynaptic inhibitory responses (c, brown) to action potentials in the interneuron (c, blue). (B) Loose patch recordings at 33DAT of a pyramidal neuron (brown) and an MGE lineage transplanted fast-spiking neuron (blue, intracellular) reveal postsynaptic excitatory responses (b, blue) to current delivery through the loose patch electrode (b, brown). (C) Summary data of the likelihood that a pyramidal cell connects to an Nkx2.1-Cre;R26-Ai14 neuron (left) or the reverse (right). White text: number of observed connections (top) vs. number of connections tested (bottom). (D) Quantification of amplitudes of EPSPs (blue) from host pyramidal neurons onto transplant-derived MGE lineage interneurons and IPSPs (with postsynaptic neuron at −60 mV) of transplant-derived neuron onto host pyramidal neuron. Circles transplant-derived neuron was FS; triangles: non-FS. (E) Quantification of paired pulse ratios (50 ms interpulse interval) of postsynaptic response amplitudes. (F) Quantification of latency from action potential to PSP onset.
Figure 5
Figure 5. Transplant-Derived CGE Lineage Interneurons Form Functional Synapses with Host Excitatory and Inhibitory Neurons
(A) Whole-cell recordings from a host pyramidal neuron (brown) and a fluorescently labeled transplanted CGE continuous adapting interneuron (red) demonstrate an EPSP onto the postsynaptic CGE-derived neuron (c, bold trace is average of 10 responses) when the presynaptic pyramidal neuron fires an action potential (c, brown). (B) Intracellular recordings from a fluorescently labeled transplanted CGE burst nonadapting non-fast spiking interneuron (red) and a host pyramidal neuron (brown) demonstrate an IPSP onto the pyramidal neuron following action potentials elicited in the interneuron (c, bold trace is average of 10 responses). (C) Recordings from a fluorescently labeled transplanted CGE continuous non-adapting non-fast spiking interneuron (Nkx2.1-Cre;R26-GDTA donor into an SST-Cre;R26-Ai14 host; red) and a fluorescently labeled host interneuron (purple) show an IPSP in the host interneuron (c, bold is average of 10 responses) following evoked action potentials in the CGE transplant-derived neuron. (D) Recordings from a host interneuron (VIP-Cre;R26-Ai14 donor into a GAD67-GFP host) show an IPSP onto the transplant-derived CGE lineage continuous irregular firing interneuron (c, bold is average of 10 responses). (E) Quantification of EPSP amplitude from a host pyramidal neuron to a transplant-derived CGE lineage interneuron (red), and IPSP amplitude of transplant-derived CGE lineage interneuron onto host pyramidal neuron (brown), transplant-derived CGE lineage interneuron onto host interneuron (purple), and host interneuron onto transplant-derived CGE lineage interneuron (red). (F) Quantification of paired pulse ratios for postsynaptic responses to presynaptic action potentials separated by 50 ms. (G) Postsynaptic potential onset latency quantifications. (H) Example trace demonstrating automated EPSP detection (red bars) used in J–K. (I) Spontaneous EPSPs onto transplanted CGE neurons are small (bar is mean±SE), though they do also receive infrequent larger inputs (ordinate is logarithmic; n=16 neurons for which >60 s of spontaneous activity were recorded). (J) All CGE transplant-derived neurons (n=48) received spontaneous EPSPs. (K) Extracellular minimal stimulation in cortical layer I (asterisk) reliably generates EPSPs onto a CGE transplant-derived neuron (amplitude 0.89±0.08 mV for driven vs. 0.65±0.41 mV for spontaneous EPSPs, p>0.05). Short latency EPSPs were routinely seen with layer I stimulation (7 of 7 CGE neurons tested, latency 4.7±1.3 ms). (L) Amplitude of EPSP evoked by layer I stimulation with the postsynaptic neuron held at −70 mV (n=5 neurons, 1.41±0.33 mV).
Figure 6
Figure 6. Activity in CGE Transplant-Derived VIP Expressing Interneurons is Visually Modulated
(A) Donor CGE tissue (VIP-Cre;R26-Ai14) was harvested at E13.5 and transplanted at P7 into wild type hosts. AAV-2/5-CAG-flex-GCaMP6s was injected into visual cortex at P30 and in vivo two photon calcium responses to rotated drifting gratings were obtained 3 weeks later in transplant-derived neurons (tdTomato+). (B) Calcium responses of a transplanted VIP neuron to drifting gratings (orientation indicated by bar in upper left). Red traces represent individual trials and bold trace is the average of 6 trials (ΔF/F0 at preferred orientation = 1.46). (C) Polar chart of the response in B, averaged over the last 2 s of stimulus period, demonstrates broad tuning (OSI=0.21). (D) A second exemplar neuron with ΔF/F0= 0.88 at preferred orientation. (E) Polar chart of the averaged response in D demonstrates narrow orientation tuning for this neuron (OSI=0.54). (F) Distribution of average response magnitudes at the preferred orientation in all cells analyzed (n=37 cells in 2 mice). Responses greater than 0.1 (dashed line) were considered visually responsive. (G) Distribution of orientation selectivity in visually responsive cells (n=21 cells in 2 mice).
Figure 7
Figure 7. Genetically Purified CGE Transplants Do Not Induce A Heterochronic Critical Period
(A) R26-GDTA MGE (blue), R26-GDTA CGE (magenta) or PV-Cre;SST-Cre;R26-GDTA CGE cells (red) were harvested at E13.5, dissociated, and transplanted into the visual cortex of P7 hosts. Animals were imaged before and after a 4–5 day period of monocular deprivation starting at 29–30DAT. (B) Ocular dominance index measured before (open squares) and after (closed squares) 4–5 days of monocular deprivation of the contralateral eye demonstrate significant plasticity in MGE (blue, n=6) and CGE (magenta, n=9) cell transplant recipients. Ocular dominance index for PV and SST depleted CGE transplants (PV-Cre;SST-Cre;R26-GDTA, red, n=7) do not demonstrate significant plasticity (no change in ODI, p>0.05). Significance calculated using Bonferroni corrected Mann Whitney tests. (C) Magnitude of ODI change following deprivation. Significance calculated using Bonferroni corrected Mann Whitney tests. (D) Changes in magnitude of ipsilateral and contralateral responses after deprivation, expressed as percentage of pre-MD baseline values (dashed line). (E) Density of GFP expressing transplanted cells in the binocular visual cortex of recipients of MGE (blue, n=6), CGE (magenta, n=8) and PV-SST-depleted CGE (red, n=7) cell transplants, at 35DAT. Horizontal bars represent mean and vertical bars SEM. (F) Density of transplanted PV cells in host binocular visual cortex. (G) Density of transplanted SST cells in host binocular visual cortex. Significance calculated using Bonferroni corrected Mann Whitney test.

Similar articles

See all similar articles

Cited by 14 articles

See all "Cited by" articles

LinkOut - more resources

Feedback