Journal: eLife

Article Title: Descending locus coeruleus noradrenergic signaling to spinal astrocyte subset is required for stress-induced mechanical pain hypersensitivity

doi: 10.7554/eLife.104453

Figure Lengend Snippet: ( A ) Schematic illustration of an experiment to investigate the effects of acute exposure to restraint stress (1 hr) on mechanosensory behavior in mice, using von Frey (vF) filaments. ( B ) Change in paw withdrawal threshold (PWT) measured by vF filaments in wild-type mice after restraint stress ( n = 6 mice per group; two-way ANOVA with post hoc Bonferroni’s multiple comparisons test; *p < 0.05, **p < 0.01, ***p < 0.001, ****p < 0.0001 vs. no-restraint stress group). ( C ) Expression of GCaMP6s (GC; green) in the LC at 3 weeks after intra-LC injection of AAV-FLEx[GCaMP6s] in Slc6a2-Cre mice. TH immunofluorescence is shown in magenta. Dashed line indicates the location of the implanted optic fiber. Scale bar, 100 μm. ( D, E ) Representative traces and change in the frequency of GCaMP6s signals in LC-NA neurons ( n = 6 mice; Friedman test with post hoc Dunn’s multiple comparisons test; **p < 0.01 vs. the data of ‘Before’). Traces shown at the top, middle, and bottom ( D ) indicate Ca 2+ signals before, during, and after restraint stress, respectively. ( F ) Schematic illustration of the strategy of ablating LC-NA neurons using AAV vectors incorporating DTR (fused with EGFP) injected into the LC in Slc6a2-Cre mice. ( G ) TH immunofluorescence (magenta) and GFP (green) in the LC (left) and NET immunofluorescence (magenta) in the SDH (right) after administration of DTX (10 µg/kg, i.p., two injections 24 hr apart) in control mice (top) and DTR-expressing mice (bottom). Scale bars, 100 μm. ( H ) Effect of ablation of LC-NA neurons on PWT changes after acute restraint stress ( n = 7 mice per group; two-way ANOVA with post hoc Bonferroni’s multiple comparisons test; **p < 0.01 vs. control group). ( I ) Schematic illustration of the strategy of ablating LC →SDH -NA neurons using a retrograde AAV vector incorporating Cre injected into the SDH and an AAV vector incorporating DTR (fused with EGFP) injected into the LC in wild-type mice. ( J ) Representative images of LC →SDH -NA neurons in control or DTR-expressing mice treated with vehicle or DTX administration, respectively. GFP (green) and TH (magenta). Scale bar, 100 μm. ( K ) Effect of ablation of LC →SDH -NA neurons on PWT changes after restraint stress ( n = 11 mice per group; two-way ANOVA with post hoc Bonferroni’s multiple comparisons test; ** P <0.01 vs. control group). ( L ) Schematic illustration of the strategy for activating LC →SDH -NA neuronal axons/terminals using an AAV vector incorporating ChrimsonR (fused with tdTomato) injected into the LC in Slc6a2-Cre mice and of an optic cannula implanted in the SDH. ( M ) Representative images of TH (green) and tdTomato (magenta) expression in the LC (top) and NET (green) and tdTomato (magenta) expression in the SDH (bottom) at 3 weeks after intra-LC injection of AAV-FLEx[ChrimsonR-tdTomato] in Slc6a2-Cre mice. Scale bars, 100 μm (top) and 50 μm (bottom). ( N ) PWT before and after optogenetic stimulation (opto-stim.) in LC →SDH -NA axons/terminals (625 nm, 2 mW, 10 Hz, 5 ms pulse duration, 5 s light on, 15 s light off, 10 cycles) (Control, n = 4 mice; ChrimsonR, n = 5 mice; two-way ANOVA with post hoc Bonferroni’s multiple comparisons test; ****p < 0.0001 vs. control group). Data represent mean ± SEM. See also – . Some figure elements were created with BioRender.com . Figure 1—source data 1. Raw numerical values for plots.

Article Snippet: To activate ChrimsonR in LC →SDH -NA axons/terminals, 625 nm LED light (#M625F2; Thorlabs) was delivered through a ferrule patch cable (#M83L01; Thorlabs).

Techniques: Expressing, Injection, Immunofluorescence, Control, Plasmid Preparation

Journal: eLife

Article Title: Descending locus coeruleus noradrenergic signaling to spinal astrocyte subset is required for stress-induced mechanical pain hypersensitivity

doi: 10.7554/eLife.104453

Figure Lengend Snippet: ( A ) Representative of LC →SDH -NA neurons in DTR-expressing mice treated with vehicle (control) and DTX (ablated). Scale bar, 100 μm. ( B ) Number of TH + GFP + cells in multiple sections of the anterior and posterior regions of the LC ( n = 3–4 mice; Mann Whitney test; * P <0.05). ( C ) Representative of LC →SDH -NA neurons in DTR-expressing mice (a retrograde AAV vector incorporating Cre injected into the SDH and an AAV vector incorporating DTR (fused with EGFP) injected into the LC). DTR expression was not observed in the A5 or A7 regions, indicating that DTR expression was specific to the A6 (LC) region (this image is the same as Control in panel A ). Scale bar, 100 μm. Data show the mean ± SEM. Figure 1—figure supplement 4—source data 1. Raw numerical values for plots.

Article Snippet: To activate ChrimsonR in LC →SDH -NA axons/terminals, 625 nm LED light (#M625F2; Thorlabs) was delivered through a ferrule patch cable (#M83L01; Thorlabs).

Techniques: Expressing, Control, MANN-WHITNEY, Plasmid Preparation, Injection

Journal: eLife

Article Title: Descending locus coeruleus noradrenergic signaling to spinal astrocyte subset is required for stress-induced mechanical pain hypersensitivity

doi: 10.7554/eLife.104453

Figure Lengend Snippet: Latency to fall in the rotarod test (left) and paw withdrawal latency (PWL) in the paw-flick test (right) using mice with DTR expression in LC →SDH -NA neurons before and after injection of DTX or PBS ( n = 5 mice per group; two-tailed paired t -test and two-way repeated measures ANOVA with Bonferroni’s multiple comparisons test). Data show the mean ± SEM. Figure 1—figure supplement 5—source data 1. Raw numerical values for plots.

Article Snippet: To activate ChrimsonR in LC →SDH -NA axons/terminals, 625 nm LED light (#M625F2; Thorlabs) was delivered through a ferrule patch cable (#M83L01; Thorlabs).

Techniques: Expressing, Injection, Two Tailed Test

Journal: eLife

Article Title: Descending locus coeruleus noradrenergic signaling to spinal astrocyte subset is required for stress-induced mechanical pain hypersensitivity

doi: 10.7554/eLife.104453

Figure Lengend Snippet: Representative images of NET (green) and tdTomato (magenta) expression in the SDH at 3 weeks after intra-LC injection of AAV-FLEx[ChrimsonR-tdTomato] in Slc6a2-Cre mice. Scale bar, 200 µm (left) and 50 µm (right).

Article Snippet: To activate ChrimsonR in LC →SDH -NA axons/terminals, 625 nm LED light (#M625F2; Thorlabs) was delivered through a ferrule patch cable (#M83L01; Thorlabs).

Techniques: Expressing, Injection

Journal: eLife

Article Title: Descending locus coeruleus noradrenergic signaling to spinal astrocyte subset is required for stress-induced mechanical pain hypersensitivity

doi: 10.7554/eLife.104453

Figure Lengend Snippet: ( A ) Schematic illustration of intra-SDH microinjection of AAV-gfaABC 1 D-GRAB NE1m or -GCaMP6m and intra-LC microinjection of AAV-FLEx[ChrimsonR-tdTomato] in Slc6a2-Cre mice. ( B ) Representative traces of GRAB NE1m signals by fluorescence imaging using spinal cord slices. Each trace represents the GRAB NE1m signal before and after optogenetic stimulation (625 nm, 1 mW, 10 Hz, 5ms pulse duration, 1–20 s). ( C ) Quantitative analysis of the peak amplitude of GRAB NE1m Δ F / F after optogenetic stimulation in LC →SDH -NA axons/terminals ( n = 4 slices; one-way ANOVA with post hoc Dunnett’s multiple comparisons test; **p < 0.01, ****p < 0.0001). ( D ) Representative traces of astrocytic GCaMP6m signals by fluorescence imaging using spinal cord slices. Each trace represents the GCaMP6m signal before and after optogenetic stimulation (as described in B). ( E ) Quantitative analysis of the peak amplitude of GCaMP6m Δ F / F after optogenetic stimulation in LC →SDH -NA axons/terminals ( n = 133 cells, 4 slices, 4 mice; Friedman test with post hoc Dunn’s multiple comparisons test; ****p < 0.0001). ( F ) Effect of silodosin (40 nM) on astrocytic Ca 2+ responses in the SDH after optogenetic stimulation (10 s) in LC →SDH -NA axons/terminals (Control, n = 83 cells, 4 slices, 4 mice; Silodosin, n = 53 cells, 4 slices, 4 mice; Mann–Whitney test; ****p < 0.0001). ( G ) Effect of intrathecal silodosin (3 nmol) on mechanical hypersensitivity induced by optogenetic stimulation in LC →SDH -NA axons/terminals (Vehicle, n = 5 mice; Silodosin, n = 6 mice; two-way ANOVA with post hoc Bonferroni’s multiple comparisons test; *p < 0.05, ***p < 0.001 vs. vehicle group). ( H ) Change in PWT at 30 min after intrathecal injection of NA (0.1 nmol) in control ( Adra1a flox/flox ) and Hes5 + astrocyte-selective α 1A R conditional knockout mice Hes5-CreERT2;Adra1a flox/flox mice treated with tamoxifen (TAM) ( Hes5 + astrocyte–α 1A R cKO mice) ( n = 6 mice per group; two-way ANOVA with post hoc Bonferroni’s multiple comparisons test; ****p < 0.0001). ( I , J ) Stress-induced mechanical hypersensitivity in Hes5 + astrocyte–α 1A R cKO mice [I: Control ( Adra1a flox/flox ), n = 7 mice; Hes5 + astrocyte–α 1A R cKO, n = 8 mice] or wild-type mice with intrathecal DCK (10 nmol) ( J : n = 5 mice per group) (two-way ANOVA with post hoc Bonferroni’s multiple comparisons test; **p < 0.01, ***p < 0.001 vs. control or vehicle group). Data represent mean ± SEM. Some figure elements were created with BioRender.com . Figure 2—source data 1. Raw numerical values for plots.

Article Snippet: To activate ChrimsonR in LC →SDH -NA axons/terminals, 625 nm LED light (#M625F2; Thorlabs) was delivered through a ferrule patch cable (#M83L01; Thorlabs).

Techniques: Microinjection, Fluorescence, Imaging, Control, MANN-WHITNEY, Injection, Knock-Out

Journal: eLife

Article Title: Descending locus coeruleus noradrenergic signaling to spinal astrocyte subset is required for stress-induced mechanical pain hypersensitivity

doi: 10.7554/eLife.104453

Figure Lengend Snippet: Intrathecal NA ( A , 0.1 nmol) or Phe ( B , 0.05 nmol)-induced mechanical hypersensitivity in control ( Adra1a flox/flox ) and Slc32a1 + IN-selective α 1A R conditional knockout mice [ Slc32a1-Cre;Adra1a flox/flox mice ( Slc32a1 + INs–α 1A R cKO mice)] ( n = 6 mice per group; two-way ANOVA with post hoc Bonferroni’s multiple comparisons test; n.s., not significant). ( C ) Changes in PWT after acute exposure to restraint stress in control ( Adra1a flox/flox ; n = 6 mice) and Slc32a1 + INs–α 1A R cKO mice ( n = 9 mice) (two-way ANOVA with post hoc Bonferroni’s multiple comparisons test). ( D ) Representative trace of membrane potentials in tdTomato + ( Slc32a1 + ) SDH neurons after application of NA (20 μM) to spinal cord slices from Slc32a1-Cre;Rosa26-LSL-tdTomato mice. A 1 R agonist CPA (1 μM) was co-applied with NA. ( E ) Percentage of Slc32a1 + SDH neurons whose NA-evoked response was inhibited by CPA ( n = 10 cells from 7 mice). ( F ) Representative images of Adora1 (A 1 R) mRNA expression (green) in Slc32a1 + INs (magenta). DAPI staining is shown in gray. Arrowheads indicate A 1 R-expressing Slc32a1 + cells. Scale bar, 25 μm. ( G ) SaCas9 (yellow, detected by HA-tag) and mCherry (magenta) expression in the PAX2 + INs (cyan) at 3 weeks after intra-SDH injection of AAV-FLEx[SaCas9] and AAV-FLEx[mCherry]-U6-sgAdora1 in Slc32a1-Cre mice. Arrowheads indicate genome-editing Slc32a1 + cells. Scale bar, 25 μm. ( H ) Representative traces of membrane potentials in Slc32a1 + INs after application of NA and CPA to spinal cord slices from Slc32a1-Cre mice with conditional knockdown of A 1 Rs in Slc32a1 + INs (SDH- Slc32a1 + IN–A 1 R cKD) and their controls (Control; Slc32a1-Cre mice with intra-SDH injection of AAV-FLEx[mCherry]). ( I ) Percentage of mCherry + ( Slc32a1 + ) SDH neurons whose NA-evoked response was inhibited by CPA (Control, n = 10 cells from 8 mice; SDH- Slc32a1 + IN–A 1 R cKD, n = 8 cells from 5 mice). ( J ) Expression of hM3Dq (green, detected by HA-tag) in the SDH at 3 weeks after intra-SDH injection of AAV-FLEx[hM3Dq] in Hes5-CreERT2 mice treated with TAM. Dashed line indicates an outline of the gray matter of SDH. GFAP (magenta, bottom left), SOX9 (magenta, bottom right). Arrowheads indicate HA-tag + astrocytes. Scale bars, 200 μm (top) and 25 μm (bottom). Representative traces of spontaneous inhibitory postsynaptic currents (sIPSCs) ( K ) and quantitative analysis of their frequency ( L ) in SG neurons in spinal cord slices from Hes5-CreERT2 ;AAV-hM3Dq mice treated with TAM [Pre and CNO: before and after bath application of CNO (100 μM), respectively] ( n = 7 cells from 7 mice; Wilcoxon signed-rank test; *p < 0.05). Representative traces of sIPSCs ( M ) and quantitative analysis of their frequency ( N ) in SG neurons in spinal cord slices from Hes5-CreERT2 ;AAV-FLEx[hM3Dq] mice treated with TAM [Pre and CNO: before and after bath application of CNO with CPT (1 μM), respectively] ( n = 13 cells from 13 mice; Wilcoxon signed-rank test; n.s., not significant). Data represent mean ± SEM. See also and . Figure 3—source data 1. Raw numerical values for plots.

Article Snippet: To activate ChrimsonR in LC →SDH -NA axons/terminals, 625 nm LED light (#M625F2; Thorlabs) was delivered through a ferrule patch cable (#M83L01; Thorlabs).

Techniques: Control, Knock-Out, Membrane, Expressing, Staining, Injection, Knockdown

Journal: eLife

Article Title: Descending locus coeruleus noradrenergic signaling to spinal astrocyte subset is required for stress-induced mechanical pain hypersensitivity

doi: 10.7554/eLife.104453

Figure Lengend Snippet: ( A ) Representative images of the astrocytic Ca 2+ response by NA (10 µM) or CNO (100 µM). Fluorescence intensity of GCaMP6m in wild-type; AAV-mCherry mice with GCaMP6m expression in SDH astrocytes. ( B ) Effect of CNO (1, 10, and 100 µM) on the astrocytic Ca 2+ response in Hes5-CreERT2 ;AAV-FLEx[hM3Dq] mice with GCaMP6m expression in SDH astrocytes. ( C ) Frequency of spontaneous inhibitory postsynaptic currents (sIPSCs) in SG neurons in the SDH from Hes5-CreERT2 ;AAV-mCherry mice treated with TAM [Pre and CNO: before and after bath application of CNO (100 μM), respectively] ( n = 8 cells from 8 mice; Wilcoxon signed-rank test; p = 0.5781). Data show the mean ± SEM. Figure 3—figure supplement 1—source data 1. Raw numerical values for plots.

Article Snippet: To activate ChrimsonR in LC →SDH -NA axons/terminals, 625 nm LED light (#M625F2; Thorlabs) was delivered through a ferrule patch cable (#M83L01; Thorlabs).

Techniques: Fluorescence, Expressing

Journal: eLife

Article Title: Descending locus coeruleus noradrenergic signaling to spinal astrocyte subset is required for stress-induced mechanical pain hypersensitivity

doi: 10.7554/eLife.104453

Figure Lengend Snippet: PWT before and 30 min after intrathecal administration of NA (0.1 nmol) in wild-type mice pretreated intrathecally with vehicle or CPT (3 nmol) ( A : n = 5 mice per group) or in control ( Slc32a1-Cre mice with intra-SDH of AAV-FLEx[mCherry]) and SDH- Slc32a1 + IN–A 1 R cKD mice ( B : n = 9 mice per group) (two-way ANOVA with post hoc Bonferroni’s multiple comparisons test; ***p < 0.001). PWT before and after acute restraint stress in wild-type mice pretreated intrathecally with vehicle or CPT ( C : Vehicle, n = 6 mice; CPT, n = 5 mice) or in control ( Slc32a1-Cre mice with intra-SDH of AAV-FLEx[mCherry]) and SDH- Slc32a1 + IN–A 1 R cKD mice ( D : Control, n = 6 mice; SDH- Slc32a1 + IN–A 1 R cKD, n = 7 mice) (two-way ANOVA with post hoc Bonferroni’s multiple comparisons test; *p < 0.05, **p < 0.01, ***p < 0.001, ****p < 0.0001 vs. vehicle or control group). ( E – H ) Representative images of c-FOS (green, E ), pERK (green, G ), and IB4 (magenta, E , G ) immunofluorescence in the SDH with or without Aβ fiber stimulation and/or restraint stress. CPT was intrathecally administered 30 min before stress exposure. Quantitative analysis of the number of c-FOS + ( F ) and pERK + ( H ) cells in superficial laminae of the SDH in each group ( n = 4–5 mice per group; one-way ANOVA with post hoc Tukey’s multiple comparisons test; *p < 0.05, ***p < 0.001, ****p < 0.0001). ( I ) Schematic illustration of the mechanisms of stress-induced mechanical pain facilitation highlighting NA signals from LC →SDH -NAergic terminals to Hes5 + astrocytes and Slc32a1 + INs. Data represent mean ± SEM. Some figure elements were created with BioRender.com . Figure 4—source data 1. Raw numerical values for plots.

Article Snippet: To activate ChrimsonR in LC →SDH -NA axons/terminals, 625 nm LED light (#M625F2; Thorlabs) was delivered through a ferrule patch cable (#M83L01; Thorlabs).

Techniques: Control, Immunofluorescence