Journal: iScience

Article Title: ER stress in mouse serotonin neurons triggers a depressive phenotype alleviated by ketamine targeting eIF2α signaling

doi: 10.1016/j.isci.2024.109787

Figure Lengend Snippet: Activation of ERS in DR in mouse models based on lipopolysaccharide (LPS)-induced neuroinflammation or chronic exposure to corticosterone stress (CORT) (A) Treatment schedule. Different groups of mice were treated with i) a single dose of LPS (0.83 mg/kg, ip) and examined 12 h post-administration, or ii) chronic CORT exposure in the drinking water for 28 days and examined on day 36. (B) In the tail suspension test (TST), the immobility time was compared between Veh ( n = 6) and LPS ( n = 6) or Veh ( n = 10) and CORT ( n = 9) mice. (C) BDNF protein levels in the DR were analyzed by Western blot (WB) and compared between Veh ( n = 5) and LPS ( n = 9) or Veh ( n = 5) and CORT ( n = 8) mice. (D) BiP protein levels in the DR were analyzed by WB and compared between Veh ( n = 5) and LPS ( n = 9) or Veh ( n = 5) and CORT ( n = 9) mice. (E) GRP94 protein levels in the DR were analyzed by WB and compared between Veh ( n = 5) and LPS ( n = 9) or Veh ( n = 5) and CORT ( n = 9) mice. (F) CHOP protein levels in the DR were analyzed by WB and compared between Veh ( n = 5) and LPS ( n = 9) or Veh ( n = 5) and CORT ( n = 8) mice. (G) eIF2α and p -eIF2α protein levels in the DR were analyzed by WB and compared between Veh ( n = 5) and LPS ( n = 9) or Veh ( n = 5) and CORT ( n = 9) mice. (H) eEF2 and p -eEF2 protein levels in the DR were analyzed by WB and compared between Veh ( n = 5) and LPS ( n = 9) or Veh ( n = 5) and CORT ( n = 9) mice. Data are expressed as mean ± SEM. ∗ p < 0.05, ∗∗ p < 0.01, ∗∗∗ p < 0.001 by two-tailed t-test, see .

Article Snippet: Sessions were videotaped for 6 min and the immobility time was measured (Smart, Panlab, Cornella, Spain).

Techniques: Activation Assay, Suspension, Western Blot, Two Tailed Test

Journal: iScience

Article Title: ER stress in mouse serotonin neurons triggers a depressive phenotype alleviated by ketamine targeting eIF2α signaling

doi: 10.1016/j.isci.2024.109787

Figure Lengend Snippet: Activating ERS in DR induces a depressive-like phenotype in mice (A) Schematic time course diagram. Mice were injected with 1μL tunicamycin (Tm, 200 ƞg/μl) or vehicle (Veh, 4% DMSO in artificial cerebrospinal fluid-aCSF) into the dorsal raphe nucleus (DR) and examined after 1, 3, and 7 days. (B) In the tail suspension test (TST), the immobility time of Veh ( n = 11) and Tm ( n = 6) mice was compared. (C) In the dark-light box (DLB), latency to enter and the number of entries into the light chamber were compared between Veh ( n = 11) and Tm ( n = 6) mice. (D) During the 15 min observation period, the total distance and mean speed were recorded for Veh ( n = 10) and Tm ( n = 6) mice in the open field test (OFT). (E) BiP protein levels in the DR were analyzed by Western blot (WB) and compared between Veh ( n = 11) and Tm ( n = 6) mice. (F) GRP94 protein levels in the DR were analyzed by WB and compared between Veh ( n = 8) and Tm ( n = 5) mice. (G) eIF2α and p -eIF2α protein levels in the DR were analyzed by WB and compared between Veh ( n = 8) and Tm ( n = 6) mice. (H) eEF2 and p -eEF2 protein levels in the DR were analyzed by WB and compared between Veh ( n = 8) and Tm ( n = 6) mice. (I) Photomicrographs showing TPH-positive or GABA-positive cells expressing Egr1 mRNA ( 33 P-oligonucleotide silver grains) in the DR of Veh and Tm mice. Scale bar: 20 μm. White arrowheads indicate TPH-positive or GABA-positive cells co-localizing with Egr1 mRNA. (J) The total number of TPH-positive or GABA-positive cells and the percentage of TPH- or GABA-positive cells expressing Egr1 mRNA were analyzed in Veh ( n = 5) and Tm ( n = 4) mice. Data are expressed as mean ± SEM. ∗ p < 0.05, ∗∗ p < 0.01, ∗∗∗ p < 0.001, ∗∗∗∗ p < 0.0001 by one-way ANOVA, see . See also Figures S1‒S3 .

Article Snippet: Sessions were videotaped for 6 min and the immobility time was measured (Smart, Panlab, Cornella, Spain).

Techniques: Injection, Suspension, Western Blot, Expressing

Journal: iScience

Article Title: ER stress in mouse serotonin neurons triggers a depressive phenotype alleviated by ketamine targeting eIF2α signaling

doi: 10.1016/j.isci.2024.109787

Figure Lengend Snippet: Ketamine alleviates depressive-like phenotype by reducing ERS in raphe 5-HT neurons (A) Treatment schedule. Mice were injected with 1 μL Tm (200 ƞg/μl) or Veh (aCSF+DMSO 4%) into the DR, 24 h later received Ketamine (Ket, 10 mg/kg, ip) or Veh (saline solution, ip), and examined 30 min or 48 h post-Ket. (B) In the TST, the immobility time was recorded in Ket-treated Veh and Tm mice ( n = 5 to 8 per group). (C) BDNF protein levels in the DR were analyzed by WB. They were compared between Veh and Tm mice treated with Ket ( n = 5 to 8 per group). (D) Representative coronal midbrain sections showing TPH-positive cells expressing different NMDAR subunits including GluN1, GluN2B, and GluN2D mRNA in the DR of wild-type mice. The bottom row shows high magnification photomicrographs of the frames in the top row. The + symbol indicates TPH- and NMDA subunits-positive cells. Scale bars: low = 100 μm, high = 20 μm. (E) BiP protein levels in the DR were analyzed by WB and compared between Veh and Tm mice treated with Ket ( n = 4 to 5 per group). (F) GRP94 protein levels in the DR were analyzed by WB and compared between Ket-treated Veh and Tm mice ( n = 4 to 5 per group). (G) eIF2α and p -eIF2α protein levels in the DR were analyzed by WB and compared between Ket-treated Veh and Tm mice ( n = 4 to 5 per group). (H) eEF2 and p -eEF2 protein levels in the DR were analyzed by WB and compared between Ket-treated Veh and Tm mice ( n = 4 to 5 per group). Data are expressed as mean ± SEM. ∗ p < 0.05, ∗∗ p < 0.01, ∗∗∗ p < 0.001, ∗∗∗∗ p < 0.0001 by one-way ANOVA, see . See also Figures S6 and .

Article Snippet: Sessions were videotaped for 6 min and the immobility time was measured (Smart, Panlab, Cornella, Spain).

Techniques: Injection, Saline, Expressing

Journal: iScience

Article Title: ER stress in mouse serotonin neurons triggers a depressive phenotype alleviated by ketamine targeting eIF2α signaling

doi: 10.1016/j.isci.2024.109787

Figure Lengend Snippet: eIF2α signaling in 5-HT neurons is critical to the antidepressant effects of ketamine (A) Treatment schedule. Mice were injected with 1 μL Tm (200 ƞg/μl) or Veh (aCSF+DMSO 4%) into the DR and received two doses of ISRIB (PERK inhibitor, 0.25 mg/kg, ip) or Salubrinal (SAL, eIF2α-GADD34:PP1 phosphatase inhibitor, 1 mg/kg, ip). Ket (10 mg/kg, ip) was administered 24 h later and mice were examined 30 min after Ket administration. (B) BiP and GRP94 protein levels in mouse DR were analyzed by WB and the effects of ISRIB or SAL on Ket action were compared ( n = 7 per group). (C) eIF2α and p -eIF2α protein levels in mouse DR were analyzed by WB and the effects of ISRIB or SAL on Ket action were compared ( n = 7 per group). (D) eEF2 and p -eEF2 protein levels in mouse DR were analyzed by WB and the effects of ISRIB or SAL on Ket action were compared ( n = 7 per group). (E) In the TST, the immobility time was recorded in mice ( n = 7 to 14 per group). (F) BDNF protein levels in DR were analyzed by WB. They were compared between Veh and Tm mice treated with ISRIB or SAL and Ket ( n = 5 to 7 per group). (G) Representative images of coronal sections of the mPFC showing the mRNA expression of BDNF, TrkB, Neuritin, PSD95, VEGF, and Egr1 in the mouse model of Tm assessed by in situ hybridization. Scale bar: 1 mm. The relative density of mRNA expression of the different transcripts was compared between Veh and Tm mice treated with ISRIB or SAL and Ket ( n = 4 to 5 per group). Data are expressed as mean ± SEM. ∗ p < 0.05, ∗∗ p < 0.01, ∗∗∗ p < 0.001, ∗∗∗∗ p < 0.0001 by one-way ANOVA, see . See also Figures S8‒S14 .

Article Snippet: Sessions were videotaped for 6 min and the immobility time was measured (Smart, Panlab, Cornella, Spain).

Techniques: Injection, Expressing, In Situ Hybridization