psicor lentivirus psicor-trek-1-shrna-mcherry  (PSICOR Inc)

Journal: bioRxiv

Article Title: Channel-mediated astrocytic volume transient is required for synaptic plasticity and spatial memory

doi: 10.1101/2025.02.03.636214

Figure Lengend Snippet: (a) Schematic representation of the IOS imaging and electrophysiological setup. The CA1 region of hippocampal slices was illuminated using an infrared light source, and changes in transmittance (ΔT/T) were recorded. eEPSCs were simultaneously measured using whole-cell patch-clamp techniques. (b) IOS and eEPSC responses to TBS. TBS induces a rapid transient decrease in IOS (blue) corresponding with a significant increase in normalized eEPSC amplitudes (black). These changes reflect activity-dependent synaptic modifications. Data represent mean ± SEM. (c) Experimental design for astrocyte-specific TREK-1 knockdown and rescue. GFAP-Cre.ERT2 transgenic mice received bilateral CA1 injections of lentivirus encoding shTREK-1 or scrambled shRNA (control). Tamoxifen was administered for 7 days to induce astrocyte-specific TREK-1 knockdown, followed by electrophysiological assays 7 days post-injection. (d) Representative traces and quantification of eEPSC amplitude during 60 minutes post-TBS. TREK-1-deficient mice (pSicoR-shTREK-1 Tam(-)) exhibit significantly impaired short-term potentiation (STP) and long-term potentiation (LTP) compared to controls (pSicoR-shSCR Tam(-)). TREK-1 rescue (pSicoR-shTREK-1 Tam(+)) restores normal synaptic plasticity. (e, f) Quantification of eEPSC amplitudes immediately after TBS (e) and at the final 10 minutes of recording (f) . TREK-1 knockdown reduces synaptic potentiation, which is rescued by TREK-1 re-expression. Statistical comparisons: one-way ANOVA with post hoc tests (*p < 0.05; **p < 0.01; ns = not significant). (g) Mechanistic model for TREK-1-mediated regulation of astrocytic volume transient. TREK-1 channels mediate potassium influx during synaptic activity, creating osmotic gradients that facilitate water influx via AQP4. The resulting astrocytic swelling may mechanically modulate synapse function. In TREK-1-deficient astrocytes, impaired potassium buffering disrupts these processes, reducing synaptic efficacy. (h-k) Behavioral consequences of TREK-1 deficiency. (h) Passive avoidance task timeline. (i) TREK-1-deficient mice exhibit reduced retention latency, indicative of long-term memory deficits. (j) Object-place recognition test timeline. (k) TREK-1-deficient mice display reduced exploration of displaced objects, indicating spatial memory impairments. TREK-1 rescue restores normal performance. Statistical comparisons: two-way ANOVA with post hoc tests (***p < 0.001; ****p < 0.0001; ns = not significant). Data represent mean ± SEM.

Article Snippet: Viral constructs, including pSicoR lentivirus containing shRNA targeting TREK-1 (pSicoR-TREK-1-shRNA-mCherry), TRPA1 (pSicoR-TRPA1-shRNA-mCherry), and BDNF (pSicoR-BDNF-shRNA-mCherry), as well as scrambled controls (pSicoR-scrambled-shRNA-mCherry), were loaded into a microdispenser (VWR, Radnor, PA, USA) for bilateral injection into the hippocampal CA1 region (−1.7 mm AP, ± 1.7 mm ML,1.8 mm DV from the dura).

Techniques: Imaging, Patch Clamp, Activity Assay, Knockdown, Transgenic Assay, shRNA, Control, Injection, Expressing

Journal: bioRxiv

Article Title: Channel-mediated astrocytic volume transient is required for synaptic plasticity and spatial memory

doi: 10.1101/2025.02.03.636214

Figure Lengend Snippet: (a) Schematic of hippocampal slice preparation and treatment with BAPTA and SR101. Astrocytes were loaded with BAPTA to chelate intracellular calcium, and SR101 dye was used for astrocyte visualization. (b) Time-course of eEPSC amplitudes following TBS in hippocampal slices. Control slices show robust LTP, while BAPTA-treated slices exhibit impaired LTP. Supplementing BAPTA-treated slices with BDNF restored LTP. Insets show astrocytic SR101 labeling and BAPTA loading. Data are presented as mean ± SEM. (c, d) Quantification of eEPSC amplitudes immediately after TBS (c) and during the final 10 minutes of recording (d) . BAPTA treatment reduces synaptic potentiation, which is rescued by BDNF supplementation. Statistical comparisons: one-way ANOVA with post hoc tests (*p < 0.05; ns = not significant). (e) Experimental timeline for astrocyte-specific knockdown and rescue of BDNF. Mice received bilateral CA1 injections of lentivirus encoding shBDNF or scrambled control. Astrocytic BDNF expression was restored via tamoxifen treatment. (f) eEPSC amplitude time-course following TBS in naïve, shBDNF, and tamoxifen-treated shBDNF mice. BDNF knockdown impairs LTP, while tamoxifen-mediated rescue restores normal synaptic plasticity. Representative traces are shown above the graph. (g, h) Quantification of eEPSC amplitudes immediately after TBS (g) and during the final 10 minutes of recording (h) . Statistical analysis confirms significant rescue of LTP in tamoxifen-treated shBDNF mice (*p < 0.05; **p < 0.01; ns = not significant). (i) Schematic model illustrating the role of astrocytic BDNF in synaptic plasticity. Calcium influx through TRPA1 channels in astrocytes triggers BDNF release, enhancing presynaptic neurotransmitter release. In BDNF-deficient astrocytes, this pathway is disrupted, impairing synaptic efficacy and plasticity. (j-o) Behavioral assessments of BDNF function in memory. (j, l) Passive avoidance task timelines. (k, m) BDNF knockdown reduces retention latency, reflecting deficits in long-term memory, which are rescued by tamoxifen-mediated restoration of astrocytic BDNF. (n) Object-place recognition test timeline. (o) Exploration ratios during object-place recognition. BDNF knockdown impairs spatial memory, as indicated by reduced exploration of displaced objects. Tamoxifen treatment restores performance. Statistical analysis: two-way ANOVA with post hoc tests (***p < 0.001; ****p < 0.0001; ns = not significant). Data are presented as mean ± SEM.

Article Snippet: Viral constructs, including pSicoR lentivirus containing shRNA targeting TREK-1 (pSicoR-TREK-1-shRNA-mCherry), TRPA1 (pSicoR-TRPA1-shRNA-mCherry), and BDNF (pSicoR-BDNF-shRNA-mCherry), as well as scrambled controls (pSicoR-scrambled-shRNA-mCherry), were loaded into a microdispenser (VWR, Radnor, PA, USA) for bilateral injection into the hippocampal CA1 region (−1.7 mm AP, ± 1.7 mm ML,1.8 mm DV from the dura).

Techniques: Slice Preparation, Control, Labeling, Knockdown, Expressing