Biology subjects

Nishizono, H.

Publications and source records attributed to Nishizono, H..

4 recordsLinked to original sources

bioRxiv2024

lncRNA ADEPTR loss-of-function elicits sex-specific behavioral and spine deficits

Activity-dependent changes in neuronal connections are fundamental to learning and long-term memory storage. However, the precise contribution of long noncoding RNAs (lncRNAs) to these modifications remains unclear. In this study, we assessed the role of the lncRNA ADEPTR, a cAMP-modulated lncRNA localized in dendrites, which is crucial for synapse morphology. By generating two different mouse models--one with a deletion of ADEPTR (L-ADEPTR) and one with a deletion of its protein interaction region (S-ADEPTR)--we investigated the sex-specific impacts of ADEPTR loss of function on learning, memory, dendritic arborization, and synapse morphology. Our behavioral analyses revealed a reduction in anxiety in adult male mice, while learning and memory remained unaffected in both models. Systematic evaluations of neuronal morphology across various developmental stages ([~]3-day-old postnatal neuronal cultures and postnatal 14- and 42-day-old male and female mice) uncovered substantial deficits in neuronal architecture in both S- and L-ADEPTR male and female neuronal cultures. At postnatal day 42, in contrast to their male counterparts, L-ADEPTR female mice exhibited a significant deficiency in thin spines. Additionally, we found that the expression of plasticity-related gene BDNF, and immediate early gene cFOS were enhanced in both the cortex and hippocampus of adult male and female S- and L-ADEPTR mice, suggesting the activation of a compensatory mechanism protecting against learning and memory deficits. Collectively, these observations underscore the sex-specific role of lncRNA ADEPTR in shaping neuronal morphology and anxiety behavior.

neuroscience↗

bioRxiv2021

Rapid generation of conditional knockout mice using the CRISPR-CAS9 system and electroporation for neuroscience research

The Cre/Loxp-based conditional knockout technology is a powerful tool for gene function analyses by allowing region-time-specific gene manipulation. However, inserting a pair of LoxP cassettes for generating conditional knock-out can be technically challenging and thus time- and resource-consuming. This study proposes an efficient, low-cost method to generate floxed mice using the in vitro fertilization and the CRISPR-Cas9 system over two consecutive generations. This method allowed us to produce floxed mice targeting exon 5 to exon 6 of CaMK1 in a short period, 125 days, using only 16 mice. The efficiency of generating floxed mice was 10%, significantly higher than the conventional ES cell-based method. We directly edited the genome of C57BL/6N fertilized eggs, our target genetic background, to eliminate additional backcrossing steps. We confirmed that the genome of this floxed mouse is responsive to Cre protein. This low-cost, highly efficient method for generating conditional knock-out will facilitate comprehensive, tissue-specific genome analyses.

neuroscience↗

bioRxiv2021

Systematic analysis of brain lactate and pH levels in 65 animal models related to neuropsychiatric conditions

Increased levels of lactate, an end-product of glycolysis, have been proposed as a potential surrogate marker for metabolic changes during neuronal excitation. These changes in lactate levels can result in decreased brain pH, which has been implicated in patients with various neuropsychiatric disorders. We previously demonstrated that such alterations are commonly observed in five mouse models of schizophrenia, bipolar disorder, and autism, suggesting a shared endophenotype among these disorders rather than mere artifacts due to medications or agonal state. However, there is still limited research on this phenomenon in animal models, leaving its generality across other disease animal models uncertain. Moreover, the association between changes in brain lactate levels and specific behavioral abnormalities remains unclear. To address these gaps, the International Brain pH Project Consortium investigated brain pH and lactate levels in 109 strains/conditions of 2,294 animals with genetic and other experimental manipulations relevant to neuropsychiatric disorders. Systematic analysis revealed that decreased brain pH and increased lactate levels were common features observed in multiple models of depression, epilepsy, Alzheimers disease, and some additional schizophrenia models. While certain autism models also exhibited decreased pH and increased lactate levels, others showed the opposite pattern, potentially reflecting subpopulations within the autism spectrum. Furthermore, utilizing large-scale behavioral test battery, a multivariate cross-validated prediction analysis demonstrated that poor working memory performance was predominantly associated with increased brain lactate levels. Importantly, this association was confirmed in an independent cohort of animal models. Collectively, these findings suggest that altered brain pH and lactate levels, which could be attributed to dysregulated excitation/inhibition balance, may serve as transdiagnostic endophenotypes of debilitating neuropsychiatric disorders characterized by cognitive impairment, irrespective of their beneficial or detrimental nature.

neuroscience↗

bioRxiv2017

Autophagy enhances memory erasure through synaptic destabilization

There is substantial interest in memory reconsolidation as a target for the treatment of anxiety disorders such as post-traumatic stress disorder (PTSD). However, its applicability is restricted by reconsolidation-resistant conditions that constrain the initial memory destabilization. In this study, we investigated whether the induction of synaptic protein degradation through autophagy modulation, a major protein degradation pathway, can enhance memory destabilization upon retrieval and whether it can be utilized to overcome these conditions. Here, using male mice in an auditory fear reconsolidation model, we showed that autophagy contributes to memory destabilization and its induction can be utilized to enhance erasure of a reconsolidation-resistant auditory fear memory that depended on -amino-3-hydroxy-5-methyl4-isoxazolepropionic acid receptor (AMPAR) endocytosis. Using male mice in a contextual fear reconsolidation model, autophagy induction in the amygdala or in the hippocampus enhanced fear or contextual memory destabilization, respectively. The latter correlated with AMPAR degradation in the spines of the contextual memory-ensemble cells. Using male rats in an in vivo long-term potentiation reconsolidation model, autophagy induction enhanced synaptic destabilization in an N-methyl-D-aspartate receptor-dependent manner. These data indicate that induction of synaptic protein degradation can enhance both synaptic and memory destabilization upon reactivation and that autophagy inducers have the potential to be used as a therapeutic tool in the treatment of anxiety disorders.\n\nSignificance StatementIt has been reported that inhibiting synaptic protein degradation prevents memory destabilization. However, whether the reverse relation is true and whether it can be utilized to enhance memory destabilization is still unknown. Here we addressed this question on the behavioral, molecular and synaptic levels, and showed that induction of autophagy, a major protein degradation pathway, can enhance memory and synaptic destabilization upon reactivation. We also show that autophagy induction can be utilized to overcome a reconsolidation-resistant memory, suggesting autophagy inducers as a potential therapeutic tool in the treatment of anxiety disorders.

neuroscience↗