Nuclear factor of activated T cells 4 in the prefrontal cortex is required for prophylactic actions of (R)-ketamine

Abstract

Abstract(R, S)-ketamine has prophylactic antidepressant-like effects in rodents; however, the precise molecular mechanisms underlying its action remain unknown. Using RNA-sequencing analysis, we searched novel molecular target(s) that contribute to the prophylactic effects of (R)-ketamine, a more potent enantiomer of (R, S)-ketamine. Pretreatment with (R)-ketamine (10 mg/kg, 6 days before) significantly ameliorated body weight loss, splenomegaly, and increased immobility time of forced swimming test in lipopolysaccharide (LPS: 1.0 mg/kg)-treated mice. RNA-sequencing analysis of prefrontal cortex (PFC) and subsequent IPA (Ingenuity Pathway Analysis) revealed that the nuclear factor of activated T cells 4 (NFATc4) signaling might contribute to sustained prophylactic effects of (R)-ketamine. Quantitative RT-PCR confirmed that (R)-ketamine significantly attenuated the increased gene expression of NFATc4 signaling (Nfatc4, Cd4, Cd79b, H2-ab1, H2-aa) in the PFC of LPS-treated mice. Furthermore, pretreatment with NFAT inhibitors (i.e., NFAT inhibitor and cyclosporin A) showed prophylactic effects in the LPS-treated mice. Similar to (R)-ketamine, gene knockdown of Nfatc4 gene by bilateral injection of adeno-associated virus (AAV) into the mPFC could elicit prophylactic effects in the LPS-treated mice. In conclusion, our data implicate a novel NFATc4 signaling pathway in the PFC underlying the prophylactic effects of (R)-ketamine for inflammation-related depression.

Effects of splenectomy on skin inflammation and psoriasis-like phenotype of imiquimod-treated mice

“…Spleen enlargement is linked to systemic inflammation 30 . For example, we reported splenomegaly in mice treated with lipopolysaccharide (LPS), and there were positive correlations between spleen weight and blood levels of pro-inflammatory cytokines (i.e., IL-6, tumor necrosis factor-α) [31][32][33] . A chronic social defeat stress (CSDS) model revealed that the spleen weight of susceptible mice with depression-like behaviors was higher than that www.nature.com/scientificreports/ www.nature.com/scientificreports/ of control mice and CSDS-resilient mice 34 .…”

“…A chronic social defeat stress (CSDS) model revealed that the spleen weight of susceptible mice with depression-like behaviors was higher than that www.nature.com/scientificreports/ www.nature.com/scientificreports/ of control mice and CSDS-resilient mice 34 . Collectively, it is likely that LPS-(or CSDS)-induced splenomegaly is associated with systemic inflammation [31][32][33][34][35][36] .…”

A key role of miR-132-5p in the prefrontal cortex for persistent prophylactic actions of (R)-ketamine in mice

“…Here, we found that ( R )-ketamine, but not its metabolites [( R )-norketamine and (2 R ,6 R )-HNK], produced a sustained prophylactic effect in CRS-induced depression-like behaviors in mice. We previously reported that ( R )-norketamine and (2 R ,6 R )-HNK did not show antidepressant and prophylactic effects in LPS-induced inflammation, LH, and CSDS models of depression [ 28 , 44 , 62 ]. Therefore, it is likely that ( R )-ketamine itself, but not these metabolites, could have persistent prophylactic effects in CRS-exposed mice.…”

“…The locomotion (LMT), forced swimming test (FST) and sucrose preference test (SPT) were performed as described previously [ 30 – 32 , 44 , 56 ]. An automated animal movement analysis system (SCANET MV-40; MELQUEST Co., Ltd, Toyama, Japan) was used to measure the locomotor activity of each mouse.…”

“…Western blot analysis was performed as previously reported [ 44 , 57 ]. Tissue samples from the PFC were homogenized in ice-cold Laemmli lysis buffer and centrifuged at 3000 × g for 10 min at 4 °C, to collect the supernatants.…”