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Synapse elimination and learning rules co-regulated by MHC class I H2-Db.

Lee H, Brott BK, Kirkby LA, Adelson JD, Cheng S, Feller MB, Datwani A, Shatz CJ - Nature (2014)

Bottom Line: This change is due to an increase in Ca(2+)-permeable AMPA (α-amino-3-hydroxy-5-methyl-4-isoxazole propionic acid) receptors.Restoring H2-D(b) to K(b)D(b)(-/-) neurons renders AMPA receptors Ca(2+) impermeable and rescues LTD.These observations reveal an MHC-class-I-mediated link between developmental synapse pruning and balanced synaptic learning rules enabling both LTD and LTP, and demonstrate a direct requirement for H2-D(b) in functional and structural synapse pruning in CNS neurons.

View Article: PubMed Central - PubMed

Affiliation: Departments of Biology and Neurobiology and Bio-X, James H. Clark Center, 318 Campus Drive, Stanford, California 94305, USA.

ABSTRACT
The formation of precise connections between retina and lateral geniculate nucleus (LGN) involves the activity-dependent elimination of some synapses, with strengthening and retention of others. Here we show that the major histocompatibility complex (MHC) class I molecule H2-D(b) is necessary and sufficient for synapse elimination in the retinogeniculate system. In mice lacking both H2-K(b) and H2-D(b) (K(b)D(b)(-/-)), despite intact retinal activity and basal synaptic transmission, the developmentally regulated decrease in functional convergence of retinal ganglion cell synaptic inputs to LGN neurons fails and eye-specific layers do not form. Neuronal expression of just H2-D(b) in K(b)D(b)(-/-) mice rescues both synapse elimination and eye-specific segregation despite a compromised immune system. When patterns of stimulation mimicking endogenous retinal waves are used to probe synaptic learning rules at retinogeniculate synapses, long-term potentiation (LTP) is intact but long-term depression (LTD) is impaired in K(b)D(b)(-/-) mice. This change is due to an increase in Ca(2+)-permeable AMPA (α-amino-3-hydroxy-5-methyl-4-isoxazole propionic acid) receptors. Restoring H2-D(b) to K(b)D(b)(-/-) neurons renders AMPA receptors Ca(2+) impermeable and rescues LTD. These observations reveal an MHC-class-I-mediated link between developmental synapse pruning and balanced synaptic learning rules enabling both LTD and LTP, and demonstrate a direct requirement for H2-D(b) in functional and structural synapse pruning in CNS neurons.

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Comparison of retinogeniculate synaptic responses in WT vs KbDb−/−(a,b): Examples of minimal stimulation for WT (open circles) and KbDb −/− (closed circles). Plot of EPSCs peak vs number of stimulations (gray box represents failures, >50%). (c) No difference in onset latency of SF-AMPA between all genotypes. Onset latency of SF-AMPA was estimated using minimal stimulation as time (ms) to reach 10% of peak IAMPA from stimulation artifact. (WT: 3.0±0.3 (n=12); KbDb−/−: 2.7±0.1 (n=23); KbDb−/−;NSEDb+: 3.0±0.2 (n=17); KbDb−/−;NSEDb−: 2.6±0.2 (n=19); p > 0.5, t-test). (d) Cumlative probability histogram shows no difference in Max-AMPA between WT and KbDb−/−. Inset: mean ± s.e.m. WT: 2.6±0.4 nA (n=14/N=6); KbDb−/−: 2.9±0.4 nA (n=22/N=8); p>0.1, Mann-Whitney. (e–h): Presynaptic release probability at KbDb−/− retinogeniculate synapses is similar to WT at P20–24. (e, f) Examples of EPSCs evoked by paired pulse stimulation of OT tract (20 Hz) from WT (e) vs KbDb −/− LGN neuron (f) individual LGN neurons using whole cell recording. (g–h) Paired-pulse depression (PPD) (%) (EPSC 2/EPSC 1) over varying intervals. WT (open circle) vs KbDb−/− (closed circle) (g) without Cyclothiazide (CTZ), a blocker of AMPA receptor desensitization. WT vs KbDb−/−: 1 Hz: 82.3±2.6 (n=10) vs 77.4±3.4 (n=8), 10 Hz: 44.9±2.3 (n=9) vs 42.8±3.9 (n=9), and 20 Hz: 37. 1±2.1 (n=10) vs 37.3±2.8 (n=9) (p>0.1 for each); (h) with CTZ (20 μM) WT vs KbDb−/−: 1 Hz: 79.0±2.4 (n=9) vs 81.8±1.1 (n=7), 10 Hz: 59.2±3.0 (n=8) vs 57.4±3.7 (n=7), and 20 Hz; 58.5±2.3 (n=8) vs 56.6±4.1 (n=7) (p>0.1 for each). N=4 for WT; N=3 for KbDb−/− for (g–h). There was no significant difference in PPD between WT and KbDb−/−, but note significant decrease of PPD +20 μM CTZ vs 0 μM CTZ application for both WT and KbDb−/− at 10 Hz and 20 Hz (p < 0.05). t-test. mean ± s.e.m. n=cells/N=animals.
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Figure 6: Comparison of retinogeniculate synaptic responses in WT vs KbDb−/−(a,b): Examples of minimal stimulation for WT (open circles) and KbDb −/− (closed circles). Plot of EPSCs peak vs number of stimulations (gray box represents failures, >50%). (c) No difference in onset latency of SF-AMPA between all genotypes. Onset latency of SF-AMPA was estimated using minimal stimulation as time (ms) to reach 10% of peak IAMPA from stimulation artifact. (WT: 3.0±0.3 (n=12); KbDb−/−: 2.7±0.1 (n=23); KbDb−/−;NSEDb+: 3.0±0.2 (n=17); KbDb−/−;NSEDb−: 2.6±0.2 (n=19); p > 0.5, t-test). (d) Cumlative probability histogram shows no difference in Max-AMPA between WT and KbDb−/−. Inset: mean ± s.e.m. WT: 2.6±0.4 nA (n=14/N=6); KbDb−/−: 2.9±0.4 nA (n=22/N=8); p>0.1, Mann-Whitney. (e–h): Presynaptic release probability at KbDb−/− retinogeniculate synapses is similar to WT at P20–24. (e, f) Examples of EPSCs evoked by paired pulse stimulation of OT tract (20 Hz) from WT (e) vs KbDb −/− LGN neuron (f) individual LGN neurons using whole cell recording. (g–h) Paired-pulse depression (PPD) (%) (EPSC 2/EPSC 1) over varying intervals. WT (open circle) vs KbDb−/− (closed circle) (g) without Cyclothiazide (CTZ), a blocker of AMPA receptor desensitization. WT vs KbDb−/−: 1 Hz: 82.3±2.6 (n=10) vs 77.4±3.4 (n=8), 10 Hz: 44.9±2.3 (n=9) vs 42.8±3.9 (n=9), and 20 Hz: 37. 1±2.1 (n=10) vs 37.3±2.8 (n=9) (p>0.1 for each); (h) with CTZ (20 μM) WT vs KbDb−/−: 1 Hz: 79.0±2.4 (n=9) vs 81.8±1.1 (n=7), 10 Hz: 59.2±3.0 (n=8) vs 57.4±3.7 (n=7), and 20 Hz; 58.5±2.3 (n=8) vs 56.6±4.1 (n=7) (p>0.1 for each). N=4 for WT; N=3 for KbDb−/− for (g–h). There was no significant difference in PPD between WT and KbDb−/−, but note significant decrease of PPD +20 μM CTZ vs 0 μM CTZ application for both WT and KbDb−/− at 10 Hz and 20 Hz (p < 0.05). t-test. mean ± s.e.m. n=cells/N=animals.

Mentions: To obtain more quantitative information, minimal stimulation was used to estimate single fiber strength (SF-AMPA)17 (Methods and Extended Data Figure 1a,b). On average, the amplitude of SF-AMPA in KbDb−/− is almost half that of WT, and the cumulative probability distribution of EPSC amplitudes recorded from KbDb−/− LGN neurons is also consistent with the presence of smaller sized EPSCs (Figure 1d; note onset latency of SF-AMPA is similar in both genotypes (Extended Data Figure 1c)). In contrast, maximal synaptic input (Max-AMPA) is not different between WT and KbDb−/− (Extended Data Figure 1d). Fiber fraction, an index of how much each input contributes to total synaptic response15 (Methods), is half as large in KbDb−/− than WT (Figure 1e), consistent with the idea that the number of RGC synapses in KbDb−/− LGN neurons is greater than in WT. An alternative possibility - that differences can arise from altered probability of release - is unlikely because paired-pulse ratio, an index of presynaptic release probability, is similar in WT and KbDb−/− at a variety of stimulus intervals (Extended Data Figure 1e–h). Together these experiments, which directly measure the functional status of synaptic innervation, demonstrate that either or both H2-Kb and H2-Db are required for retinogeniculate synapse elimination.


Synapse elimination and learning rules co-regulated by MHC class I H2-Db.

Lee H, Brott BK, Kirkby LA, Adelson JD, Cheng S, Feller MB, Datwani A, Shatz CJ - Nature (2014)

Comparison of retinogeniculate synaptic responses in WT vs KbDb−/−(a,b): Examples of minimal stimulation for WT (open circles) and KbDb −/− (closed circles). Plot of EPSCs peak vs number of stimulations (gray box represents failures, >50%). (c) No difference in onset latency of SF-AMPA between all genotypes. Onset latency of SF-AMPA was estimated using minimal stimulation as time (ms) to reach 10% of peak IAMPA from stimulation artifact. (WT: 3.0±0.3 (n=12); KbDb−/−: 2.7±0.1 (n=23); KbDb−/−;NSEDb+: 3.0±0.2 (n=17); KbDb−/−;NSEDb−: 2.6±0.2 (n=19); p > 0.5, t-test). (d) Cumlative probability histogram shows no difference in Max-AMPA between WT and KbDb−/−. Inset: mean ± s.e.m. WT: 2.6±0.4 nA (n=14/N=6); KbDb−/−: 2.9±0.4 nA (n=22/N=8); p>0.1, Mann-Whitney. (e–h): Presynaptic release probability at KbDb−/− retinogeniculate synapses is similar to WT at P20–24. (e, f) Examples of EPSCs evoked by paired pulse stimulation of OT tract (20 Hz) from WT (e) vs KbDb −/− LGN neuron (f) individual LGN neurons using whole cell recording. (g–h) Paired-pulse depression (PPD) (%) (EPSC 2/EPSC 1) over varying intervals. WT (open circle) vs KbDb−/− (closed circle) (g) without Cyclothiazide (CTZ), a blocker of AMPA receptor desensitization. WT vs KbDb−/−: 1 Hz: 82.3±2.6 (n=10) vs 77.4±3.4 (n=8), 10 Hz: 44.9±2.3 (n=9) vs 42.8±3.9 (n=9), and 20 Hz: 37. 1±2.1 (n=10) vs 37.3±2.8 (n=9) (p>0.1 for each); (h) with CTZ (20 μM) WT vs KbDb−/−: 1 Hz: 79.0±2.4 (n=9) vs 81.8±1.1 (n=7), 10 Hz: 59.2±3.0 (n=8) vs 57.4±3.7 (n=7), and 20 Hz; 58.5±2.3 (n=8) vs 56.6±4.1 (n=7) (p>0.1 for each). N=4 for WT; N=3 for KbDb−/− for (g–h). There was no significant difference in PPD between WT and KbDb−/−, but note significant decrease of PPD +20 μM CTZ vs 0 μM CTZ application for both WT and KbDb−/− at 10 Hz and 20 Hz (p < 0.05). t-test. mean ± s.e.m. n=cells/N=animals.
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Figure 6: Comparison of retinogeniculate synaptic responses in WT vs KbDb−/−(a,b): Examples of minimal stimulation for WT (open circles) and KbDb −/− (closed circles). Plot of EPSCs peak vs number of stimulations (gray box represents failures, >50%). (c) No difference in onset latency of SF-AMPA between all genotypes. Onset latency of SF-AMPA was estimated using minimal stimulation as time (ms) to reach 10% of peak IAMPA from stimulation artifact. (WT: 3.0±0.3 (n=12); KbDb−/−: 2.7±0.1 (n=23); KbDb−/−;NSEDb+: 3.0±0.2 (n=17); KbDb−/−;NSEDb−: 2.6±0.2 (n=19); p > 0.5, t-test). (d) Cumlative probability histogram shows no difference in Max-AMPA between WT and KbDb−/−. Inset: mean ± s.e.m. WT: 2.6±0.4 nA (n=14/N=6); KbDb−/−: 2.9±0.4 nA (n=22/N=8); p>0.1, Mann-Whitney. (e–h): Presynaptic release probability at KbDb−/− retinogeniculate synapses is similar to WT at P20–24. (e, f) Examples of EPSCs evoked by paired pulse stimulation of OT tract (20 Hz) from WT (e) vs KbDb −/− LGN neuron (f) individual LGN neurons using whole cell recording. (g–h) Paired-pulse depression (PPD) (%) (EPSC 2/EPSC 1) over varying intervals. WT (open circle) vs KbDb−/− (closed circle) (g) without Cyclothiazide (CTZ), a blocker of AMPA receptor desensitization. WT vs KbDb−/−: 1 Hz: 82.3±2.6 (n=10) vs 77.4±3.4 (n=8), 10 Hz: 44.9±2.3 (n=9) vs 42.8±3.9 (n=9), and 20 Hz: 37. 1±2.1 (n=10) vs 37.3±2.8 (n=9) (p>0.1 for each); (h) with CTZ (20 μM) WT vs KbDb−/−: 1 Hz: 79.0±2.4 (n=9) vs 81.8±1.1 (n=7), 10 Hz: 59.2±3.0 (n=8) vs 57.4±3.7 (n=7), and 20 Hz; 58.5±2.3 (n=8) vs 56.6±4.1 (n=7) (p>0.1 for each). N=4 for WT; N=3 for KbDb−/− for (g–h). There was no significant difference in PPD between WT and KbDb−/−, but note significant decrease of PPD +20 μM CTZ vs 0 μM CTZ application for both WT and KbDb−/− at 10 Hz and 20 Hz (p < 0.05). t-test. mean ± s.e.m. n=cells/N=animals.
Mentions: To obtain more quantitative information, minimal stimulation was used to estimate single fiber strength (SF-AMPA)17 (Methods and Extended Data Figure 1a,b). On average, the amplitude of SF-AMPA in KbDb−/− is almost half that of WT, and the cumulative probability distribution of EPSC amplitudes recorded from KbDb−/− LGN neurons is also consistent with the presence of smaller sized EPSCs (Figure 1d; note onset latency of SF-AMPA is similar in both genotypes (Extended Data Figure 1c)). In contrast, maximal synaptic input (Max-AMPA) is not different between WT and KbDb−/− (Extended Data Figure 1d). Fiber fraction, an index of how much each input contributes to total synaptic response15 (Methods), is half as large in KbDb−/− than WT (Figure 1e), consistent with the idea that the number of RGC synapses in KbDb−/− LGN neurons is greater than in WT. An alternative possibility - that differences can arise from altered probability of release - is unlikely because paired-pulse ratio, an index of presynaptic release probability, is similar in WT and KbDb−/− at a variety of stimulus intervals (Extended Data Figure 1e–h). Together these experiments, which directly measure the functional status of synaptic innervation, demonstrate that either or both H2-Kb and H2-Db are required for retinogeniculate synapse elimination.

Bottom Line: This change is due to an increase in Ca(2+)-permeable AMPA (α-amino-3-hydroxy-5-methyl-4-isoxazole propionic acid) receptors.Restoring H2-D(b) to K(b)D(b)(-/-) neurons renders AMPA receptors Ca(2+) impermeable and rescues LTD.These observations reveal an MHC-class-I-mediated link between developmental synapse pruning and balanced synaptic learning rules enabling both LTD and LTP, and demonstrate a direct requirement for H2-D(b) in functional and structural synapse pruning in CNS neurons.

View Article: PubMed Central - PubMed

Affiliation: Departments of Biology and Neurobiology and Bio-X, James H. Clark Center, 318 Campus Drive, Stanford, California 94305, USA.

ABSTRACT
The formation of precise connections between retina and lateral geniculate nucleus (LGN) involves the activity-dependent elimination of some synapses, with strengthening and retention of others. Here we show that the major histocompatibility complex (MHC) class I molecule H2-D(b) is necessary and sufficient for synapse elimination in the retinogeniculate system. In mice lacking both H2-K(b) and H2-D(b) (K(b)D(b)(-/-)), despite intact retinal activity and basal synaptic transmission, the developmentally regulated decrease in functional convergence of retinal ganglion cell synaptic inputs to LGN neurons fails and eye-specific layers do not form. Neuronal expression of just H2-D(b) in K(b)D(b)(-/-) mice rescues both synapse elimination and eye-specific segregation despite a compromised immune system. When patterns of stimulation mimicking endogenous retinal waves are used to probe synaptic learning rules at retinogeniculate synapses, long-term potentiation (LTP) is intact but long-term depression (LTD) is impaired in K(b)D(b)(-/-) mice. This change is due to an increase in Ca(2+)-permeable AMPA (α-amino-3-hydroxy-5-methyl-4-isoxazole propionic acid) receptors. Restoring H2-D(b) to K(b)D(b)(-/-) neurons renders AMPA receptors Ca(2+) impermeable and rescues LTD. These observations reveal an MHC-class-I-mediated link between developmental synapse pruning and balanced synaptic learning rules enabling both LTD and LTP, and demonstrate a direct requirement for H2-D(b) in functional and structural synapse pruning in CNS neurons.

Show MeSH
Related in: MedlinePlus