Nat Neurosci. 2017 Feb;20(2):219-229. doi: 10.1038/nn.4471. Epub 2017 Jan 9.

Modulation of excitation on parvalbumin interneurons by neuroligin-3 regulates the hippocampal network.

Polepalli JS¹, Wu H², Goswami D¹, Halpern CH², Südhof TC^3,⁴, Malenka RC¹.

Author information

1: Nancy Pritzker Laboratory, Department of Psychiatry and Behavioral Sciences, Stanford University School of Medicine, Stanford, California, USA.
2: Department of Neurosurgery, Stanford University School of Medicine, Stanford, California, USA.
3: Department of Molecular and Cellular Physiology, Stanford University School of Medicine, Stanford, California, USA.
4: Howard Hughes Medical Institute, Stanford University School of Medicine, Stanford, California, USA.

Abstract

Hippocampal network activity is generated by a complex interplay between excitatory pyramidal cells and inhibitory interneurons. Although much is known about the molecular properties of excitatory synapses on pyramidal cells, comparatively little is known about excitatory synapses on interneurons. Here we show that conditional deletion of the postsynaptic cell adhesion molecule neuroligin-3 in parvalbumin interneurons causes a decrease in NMDA-receptor-mediated postsynaptic currents and an increase in presynaptic glutamate release probability by selectively impairing the inhibition of glutamate release by presynaptic Group III metabotropic glutamate receptors. As a result, the neuroligin-3 deletion altered network activity by reducing gamma oscillations and sharp wave ripples, changes associated with a decrease in extinction of contextual fear memories. These results demonstrate that neuroligin-3 specifies the properties of excitatory synapses on parvalbumin-containing interneurons by a retrograde trans-synaptic mechanism and suggest a molecular pathway whereby neuroligin-3 mutations contribute to neuropsychiatric disorders.

PMID:: 28067903
PMCID:: PMC5272845
DOI:: 10.1038/nn.4471

[Indexed for MEDLINE]

Free PMC Article

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Figure 1

NL3 deletion reduces NMDA receptor-mediated EPSCs in hippocampal PV interneurons. (a) Firing properties of CA1 PV interneurons in wild type PV-Cre and NL3^fl/PV-Cre mice. Sample traces in response to twice threshold current injection (left). Spike frequency as a function of spike number (right) is unchanged by NL3 deletion (Frequency at spikes 4–8: PV-Cre, 111 ± 10 Hz, n=6 cells; NL3^fl/PV-Cre, 115 ± 10 Hz, n=6 cells). (b) Resting membrane potential of PV interneurons is unchanged by NL3 deletion (PV-Cre, −64 ± 2 mV, n=6 cells; NL3^fl/PV-Cre, −67 ± 3 mV, n=6 cells). (c) Amplitude of fast afterhyperpolarizing potential is unchanged by NL3 deletion (PV-Cre, 18 ± 1 mV, n=4 cells; NL3^fl/PV-Cre, 15± 2 mV, n=4 cells). (d–e) (top) sample traces showing mEPSCs. (bottom) cumulative distribution plot for AMPAR mEPSC amplitudes (d) and frequency (e) showing no change due to NL3 deletion (p > 0.05, KS test for both amplitude and frequency). Inset shows average mEPSC amplitudes (d) (PV-Cre, 21 ± 2 pA, n=9 cells; NL3^fl/PV-Cre, 19 ± 2 pA, n= 8 cells; p > 0.05) and mEPSC frequency (e) (PV-Cre, 14 ± 2 Hz, n = 9 cells; NL3^fl/PV-Cre, 17 ± 3 Hz, n= 8 cells; p> 0.05). (f) (top) sample average traces showing evoked AMPAR EPSCs at −70 and +40 mV. (bottom) rectification ratio (left) measured as a ratio of peak AMPAR current at +40 mV and −60 mV is unchanged by NL3 deletion (PV-Cre, 0.13 ± 0.1, n = 19 cells; NL3^fl/PV-Cre, 0.09 ± 0.02, n= 11 cells; p> 0.05). AMPAR EPSC decay kinetics (right) fitted with a single exponential fit are unchanged by NL3 deletion (PV-Cre, 2.3 ± 0.2, n = 12 cells; NL3^fl/PV-Cre, 2.0 ± 0.2, n= 11 cells; p> 0.05). (g) Representative traces of AMPAR EPSCs recorded at −60 mV and dual component EPSC at +40 mV (left). NMDAR/AMPAR ratio (right) is reduced by NL3 deletion (PV-Cre, 0.18 ± 0.1, n = 12 cells; NL3^fl/PV-Cre, 0.07 ± 0.1, n = 12 cells; p < 0.05). (h) NMDAR EPSC rise time is unchanged by NL3 deletion (NL3^fl/PV-Cre, 1.37 ± 0.10 ms, n = 8 cells; PV-Cre, 1.64 ± 0.15 ms, n = 10 cells; p>0.05). (i) Weighted decay time constants for NMDAR EPSCs are unchanged by NL3 deletion (NL3^fl/PV-Cre, 31.0 ± 1.8 ms, n = 20 cells; PV-Cre, 36.2 ± 2.1 ms, n = 22 cells; p>0.05). (j) I–V relationship of NMDAR EPSCs is unchanged by NL3 deletion. k, Representative images from dendrites (30 μm) of hippocampal PV-Cre (left) and NL3^fl/PV-Cre neurons infected with AAV-DIO-GFP and immunolabeled for GFP (top), GluA4, PSD-95 (middle) with merged images (bottom). l, Bar graph quantifying the number of PSD-95 puncta per 30 μm of the dendrite (PV-Cre 8.2 ± 1.5, n = 9; NL3^fl/PV-Cre, 6.5 ± 1.9, n = 8; p > 0.1). m, Bar graph showing the co-localization of GluA4 and PSD-95 puncta (Co-localization coefficient in PV-Cre 0.46 ± 0.02, n = 9; NL3^fl/PV-Cre, 0.42 ± 0.02, n = 8; p > 0.1).

Modulation of excitation on parvalbumin interneurons by neuroligin-3 regulates the hippocampal network

Nat Neurosci. 2017 Feb;20(2):219-229.

Figure 2

Deletion of postsynaptic NL3 causes an increase in glutamate release probability at synapses on PV interneurons. (a) Representative traces (top) and plot (bottom) show increased input-output relationship of AMPAR EPSCs in cells lacking NL3 for incremental stimulation intensities (in V) 2.5, 5,7.5,10, 12.5, 15, 17.5 and 20 (PV-Cre, 12.3 ± 7.1, 49.8 ± 21.6, 114.9 ± 34.7, 181.1 ± 56.5, 241.3 ± 68.8, 252.4 ± 78.5, 224.6 ± 62.1, 215.1 ± 56.4, n = 7 cells; NL3^fl/PV-Cre, 4.9 ± 2.0, 74.5 ± 12.5, 189.7 ± 32.5, 319.8 ± 55.8, 446.8 ± 59.7, 563.4 ± 77.6, 576.5 ± 75.3, 521.2 ± 72.7, n = 7 cells; p= 0.33, 0.34, 0.14, 0.10, 0.02, 0.01, 0.003, 0.006 for each stimulus intensity) (b) Representative average traces (top) and plot (bottom) show reduced paired pulse ratios at inter-stimulus intervals of 20, 50, 100 and 200 ms in cells lacking NL3 (PV-Cre, 2.5 ± 0.1, 2.2 ± 0.1, 1.6 ± 0.1, 1.4 ± 0.1, n = 11 cells; NL3^fl/PV-Cre, 1.8 ± 0.1, 1.6 ± 0.1, 1.4 ± 0.1, 1.1 ± 0.1, n = 12 cells; p < 0.01, 0.01, 0.05, 0.05 for each inter-stimulus interval). (c–d) (top) sample traces showing spontaneous EPSCs. (bottom) cumulative distribution plot for AMPAR sEPSC amplitudes (c) and frequency (d) showing unchanged sEPSC amplitude and increased sEPSC frequency as a result of NL3 deletion (p = 0.3, Mann-Whitney test for amplitude, p = 0.03 Mann-Whitney test for frequency). Inset shows average sEPSC amplitudes (c) (PV-Cre, 20.5 ± 0.9 pA, n= 10 cells; NL3^fl/PV-Cre, 22.1 ± 1.8 pA, n= 10 cells) and mEPSC frequency (d) (PV-Cre, 17.9 ± 1.4 Hz, n = 10 cells; NL3^fl/PV-Cre, 23.6 ± 1.6 Hz, n= 10 cells) (e) Representative traces (top) for 1^st, 10^th, 50^th and 120^th NMDAR EPSC at +40 mV following 10 min wash-in of 40 μM MK-801 and summary time course (bottom) showing an accelerated block of NMDAR EPSC in cells lacking NL3. (f) Double exponential fit for the weighted decay time constant of MK-801 block (top) in PV-Cre and NL3^fl/PV-Cre cells and summary bar graph with mean decay time constant of MK 801 block (bottom) (PV-Cre, τ_w = 215 ± 25 ms, n = 6 cells; NL3fl/PV-Cre, 112 ± 19 ms, n = 5 cells; p < 0.05 ).

Modulation of excitation on parvalbumin interneurons by neuroligin-3 regulates the hippocampal network

Nat Neurosci. 2017 Feb;20(2):219-229.

Figure 5

Changes in hippocampal network activity as a result of NL3 deletion from PV interneurons. a, Representative unfiltered in vivo LFP traces (top), 3–12 Hz band passed filtered LFP (middle) and 35–85 Hz band pass filtered LFP (bottom) recorded in the CA1 pyramidal cell layer from PV-Cre (left) and NL3^fl/PV-Cre (right) mice. b, Normalized power spectrum of the band pass filtered LFP (3–200 Hz) from PV-Cre (n = 5) and NL3^fl/PV-Cre (n = 4) mice (left). Power spectra in the 30–90 Hz range are presented in the inset to emphasize the reduction in gamma power in NL3^fl/PV-Cre mice. c, (left) Bar graph quantifying the theta power (PV-Cre, 408.6 ± 93.2, n = 5; NL3^fl/PV-Cre, 248 ± 53.9, n = 4; p > 0.1), and (right) bar graph showing a reduction in the power of the gamma in NL3^fl/PV-Cre mice (PV-Cre, 12.9 ± 1.4, n = 5; NL3^fl/PV-Cre, 4.1 ± 2.1, n = 4; *p < 0.05) (right).d–i, Sharp wave ripples are dramatically reduced in NL3^fl/PV-Cre mice. d, representative 100–300 Hz band passed filtered signals showing SWRs from PV-Cre and NL3fl/PV-Cre mice and two representative SWRs from PV-Cre and NL3fl/PV-Cre overlapped. e, Normalized power spectrum of the captured SWRs shows a reduction in the power of the SWR in NL3^fl/PV-Cre mice. f, Bar graph quantifying the normalized power of the SWRs (PV-Cre, 0.5 ± 0.06, n = 182 events; NL3^fl/PV-Cre, 0.1 ± 0.02, n = 352 events; *p < 0.005). g, Normalized average amplitude of the SWR is reduced in NL3^fl/PV-Cre mice (PV-Cre, 40.5 ± 1.3, n = 182 events; NL3^fl/PV-Cre, 13.2 ± 1.5, n = 352 events; *p < 0.005). h, Length of SWR is reduced in NL3^fl/PV-Cre mice (PV-Cre, 135 ± 4.3 ms, n = 182 events; NL3^fl/PV-Cre, 75.5 ± 2.2ms, n = 352 events; *p < 0.005). i, Rate of SWR incidence is not significantly altered in NL3^fl/PV-Cre mice (PV-Cre, 0.56 ± 0.02 Hz, n = 5 mice; NL3^fl/PV-Cre, 0.088 ± 0.01, n = 4 mice; p = 0.06). j, Representative 100–400 Hz band passed filtered LFP traces containing sharp wave ripples (SWR). k, LFPs in NL3^fl/PV-Cre slices show reduced power in 100–200 Hz bandwidth. Data are represented as mean ± 95% confidence limits l, Bar graph showing average LFP power in the 100–200 Hz range (in PV-Cre, 0.32 ± 0.02 μV²/Hz, n = 13 slices; NL3^fl/PV-Cre, 0.21 ± 0.02 μV²/Hz, n = 13 slices; * p < 0.05, T-test). m, Amplitude of SWRs (PV-Cre, 18.7 ± 1.0 μV; NL3^fl/PV-Cre, 17.0 ± 1.1 μV; p > 0.05). n, Length of SWRs are reduced in NL3^fl/PV-Cre mice (PV-Cre, 104.2 ± 8.5 ms, n = 10 slices; NL3^fl/PV-Cre, 69.9 ± 8.7 ms, n = 10 slices; *p < 0.05). o, Rate of SWRs are decreased in NL3^fl/PV-Cre mice (PV-Cre, 2.8 ± 0.4 Hz; NL3^fl/PV-Cre, 1.5 ± 0.2 Hz; * p < 0.05, T-test).

Modulation of excitation on parvalbumin interneurons by neuroligin-3 regulates the hippocampal network

Nat Neurosci. 2017 Feb;20(2):219-229.