scholarly journals Adulthood Deficiency of the Insulin-like Growth Factor-1 Receptor in Hippocampal Neurons Impairs Cell Structure and Spatial Learning and Memory in Male and Not Female Mice

2021 ◽  
Author(s):  
Cellas A Hayes ◽  
Erik L Hodges ◽  
Jessica P Marshall ◽  
Sreemathi Logan ◽  
Julie A Farley ◽  
...  
Keyword(s):  
Growth Factor ◽  
Learning And Memory ◽  
Spatial Learning ◽  
Hippocampal Neurons ◽  
Spatial Learning And Memory ◽  
Insulin Like Growth Factor ◽  
Male Mice ◽  
Female Mice ◽  
Learning Impairments ◽  
Increased Risk

Reductions in insulin-like growth factor-1 (IGF-1) are associated with cognitive impairment and increased risk of neurodegenerative disease in advanced age. In mouse models, reduced IGF-1 early-in-life leads to memory impairments and synaptic dysfunction; however, these models are limited by systemic reductions in IGF-1. We hypothesized that IGF-1 continues to promote hippocampal neuron structure and function after development, and as such, the loss of IGF-1 signaling in adult neurons would lead to impaired spatial learning and memory. To test this, the IGF-1 receptor (IGF-1R) was genetically targeted in hippocampal neurons of adult male and female mice. Male mice deficient in neuronal IGF-1R exhibited spatial learning impairments as evidenced by increased pathlength and errors in the radial arm water maze. No differences in learning and memory were observed in female mice. Golgi-Cox staining revealed a reduced number of dendritic boutons of neurons the CA1 region of the hippocampus in male mice. Decreased MAPK and increased ROCK activity were also observed in these tissues. In vitro studies revealed that impaired neurite outgrowth due to inhibited IGF-1R signaling could be rescued by pharmacological inhibitors of ROCK. However, ROCK inhibition in neuronal IGF-1R deficient mice did not fully rescue learning impairments or bouton numbers. Together, our study highlights that IGF-1 continues to support spatial learning and memory and neuronal structure in adulthood.

scholarly journals Influence of gonadal hormones on the behavioral effects of intermittent hypoxia in mice

2015 ◽  
Vol 308 (6) ◽  
pp. R489-R499 ◽  
Author(s):  
Taryn G. Aubrecht ◽  
Richelle Jenkins ◽  
Ulysses J. Magalang ◽  
Randy J. Nelson
Keyword(s):  
Learning And Memory ◽  
Spatial Learning ◽  
Intermittent Hypoxia ◽  
Upper Airway ◽  
Premenopausal Women ◽  
Gonadal Hormones ◽  
Spatial Learning And Memory ◽  
Male Mice ◽  
Intact Male ◽  
Obstructive Sleep

Obstructive sleep apnea (OSA) is characterized by repetitive upper airway obstruction resulting in cyclic intermittent hypoxia (IH) during sleep in affected individuals. OSA occurs more frequently in postmenopausal than premenopausal women and the severity of OSA increases after menopause. Gonadal hormones can influence brain and behavior; testosterone and estrogens in particular can enhance spatial learning and memory. We hypothesized that estrogens may protect mice from IH-induced hippocampal morphological and behavioral changes. To test this hypothesis we exposed intact or gonadectomized male and female mice to room air or IH [15 cycles/h, 8 h/day, fraction of inspired oxygen (FiO2) nadir of 5%] for a total of 30 days. During the final 4 days of IH, mice were tested for anxiety- and depressive-like behaviors. After cessation of IH exposure mice were tested on the Barnes maze and passive avoidance tests to assess learning and memory. Ovariectomy paired with IH treatment, impaired spatial learning and memory compared to all other female groups. Intact male mice receiving IH treatment also had impaired learning and memory compared with intact or castrated male mice exposed to room air. Learning and memory changes were mirrored by changes in basilar dendritic length of the CA1 region of the hippocampus. These data suggest that estrogens provide protection against IH-induced deficits, whereas androgens partially exacerbate IH-induced deficits on learning and memory.

scholarly journals The Effects of Intraoperative Hypothermia on Postoperative Cognitive Function in the Rat Hippocampus and Its Possible Mechanisms

2022 ◽  
Vol 12 (1) ◽  
pp. 96
Author(s):  
Guangyan Xu ◽  
Tianjia Li ◽  
Yuguang Huang
Keyword(s):  
Working Memory ◽  
Synaptic Plasticity ◽  
Cognitive Function ◽  
Learning And Memory ◽  
Spatial Learning ◽  
Hippocampal Neurons ◽  
Spatial Working Memory ◽  
Postoperative Cognitive Dysfunction ◽  
Spatial Learning And Memory ◽  
Intraoperative Hypothermia

Intraoperative hypothermia is a common complication during operations and is associated with several adverse events. Postoperative cognitive dysfunction (POCD) and its adverse consequences have drawn increasing attention in recent years. There are currently no relevant studies investigating the correlation between intraoperative hypothermia and POCD. The aim of this study was to assess the effects of intraoperative hypothermia on postoperative cognitive function in rats undergoing exploratory laparotomies and to investigate the possible related mechanisms. We used the Y-maze and Morris Water Maze (MWM) tests to assess the rats’ postoperative spatial working memory, spatial learning, and memory. The morphological changes in hippocampal neurons were examined by haematoxylin-eosin (HE) staining and hippocampal synaptic plasticity-related protein expression. Activity-regulated cytoskeletal-associated protein (Arc), cyclic adenosine monophosphate-response element-binding protein (CREB), S133-phosphorylated CREB (p-CREB [S133]), α-amino-3-hydroxy-5-methyl-4-isoxazole propionic acid receptor 1 (AMPAR1), and S831-phosphorylated AMPAR1 (p-AMPAR1 [S831]) were evaluated by Western blotting. Our results suggest a correlation between intraoperative hypothermia and POCD in rats and that intraoperative hypothermia may lead to POCD regarding impairments in spatial working memory, spatial learning, and memory. POCD induced by intraoperative hypothermia might be due to hippocampal neurons damage and decreased expression of synaptic plasticity-related proteins Arc, p-CREB (S133), and p-AMPAR1 (S831).

scholarly journals Tumor Necrosis Factor (TNF) Is Required for Spatial Learning and Memory in Male Mice under Physiological, but Not Immune-Challenged Conditions

Cells ◽  
2021 ◽  
Vol 10 (3) ◽  
pp. 608
Author(s):  
Leda Mygind ◽  
Marianne Skov-Skov Bergh ◽  
Vivien Tejsi ◽  
Ramanan Vaitheeswaran ◽  
Kate L. Lambertsen ◽  
...  
Keyword(s):  
Tumor Necrosis Factor ◽  
Learning And Memory ◽  
Spatial Learning ◽  
Tumor Necrosis ◽  
Spatial Learning And Memory ◽  
Male Mice ◽  
Inflammatory Conditions ◽  
Baseline Conditions ◽  
The Brain ◽  
Necrosis Factor

Increasing evidence demonstrates that inflammatory cytokines—such as tumor necrosis factor (TNF)—are produced at low levels in the brain under physiological conditions and may be crucial for synaptic plasticity, neurogenesis, learning and memory. Here, we examined the effects of developmental TNF deletion on spatial learning and memory using 11–13-month-old TNF knockout (KO) and C57BL6/J wild-type (WT) mice. The animals were tested in the Barnes maze (BM) arena under baseline conditions and 48 h following an injection of the endotoxin lipopolysaccharide (LPS), which was administered at a dose of 0.5 mg/kg. Vehicle-treated KO mice were impaired compared to WT mice during the acquisition and memory-probing phases of the BM test. No behavioral differences were observed between WT and TNF-KO mice after LPS treatment. Moreover, there were no differences in the hippocampal content of glutamate and noradrenaline between groups. The effects of TNF deletion on spatial learning and memory were observed in male, but not female mice, which were not different compared to WT mice under baseline conditions. These results indicate that TNF is required for spatial learning and memory in male mice under physiological, non-inflammatory conditions, however not following the administration of LPS. Inflammatory signalling can thereby modulate spatial cognition in male subjects, highlighting the importance of sex- and probably age-stratified analysis when examining the role of TNF in the brain.

scholarly journals Wnt5a is essential for hippocampal dendritic maintenance and spatial learning and memory in adult mice

2017 ◽  
Vol 114 (4) ◽  
pp. E619-E628 ◽  
Author(s):  
Chih-Ming Chen ◽  
Lauren L. Orefice ◽  
Shu-Ling Chiu ◽  
Tara A. LeGates ◽  
Samer Hattar ◽  
...  
Keyword(s):  
Learning And Memory ◽  
Spatial Learning ◽  
Hippocampal Neurons ◽  
Pyramidal Neurons ◽  
Neuronal Morphology ◽  
Adult Brain ◽  
Receptor Expression ◽  
Spatial Learning And Memory ◽  
Brain Functions ◽  
Wnt5a Expression

Stability of neuronal connectivity is critical for brain functions, and morphological perturbations are associated with neurodegenerative disorders. However, how neuronal morphology is maintained in the adult brain remains poorly understood. Here, we identify Wnt5a, a member of the Wnt family of secreted morphogens, as an essential factor in maintaining dendritic architecture in the adult hippocampus and for related cognitive functions in mice. Wnt5a expression in hippocampal neurons begins postnatally, and its deletion attenuated CaMKII and Rac1 activity, reduced GluN1 glutamate receptor expression, and impaired synaptic plasticity and spatial learning and memory in 3-mo-old mice. With increased age, Wnt5a loss caused progressive attrition of dendrite arbors and spines in Cornu Ammonis (CA)1 pyramidal neurons and exacerbated behavioral defects. Wnt5a functions cell-autonomously to maintain CA1 dendrites, and exogenous Wnt5a expression corrected structural anomalies even at late-adult stages. These findings reveal a maintenance factor in the adult brain, and highlight a trophic pathway that can be targeted to ameliorate dendrite loss in pathological conditions.

scholarly journals Trim9 Deletion Alters the Morphogenesis of Developing and Adult-Born Hippocampal Neurons and Impairs Spatial Learning and Memory

2016 ◽  
Vol 36 (18) ◽  
pp. 4940-4958 ◽  
Author(s):  
Cortney C. Winkle ◽  
Reid H. J. Olsen ◽  
Hyojin Kim ◽  
Sheryl S. Moy ◽  
Juan Song ◽  
...  
Keyword(s):  
Learning And Memory ◽  
Spatial Learning ◽  
Hippocampal Neurons ◽  
Spatial Learning And Memory

scholarly journals Deficiency of Intellectual Disability-Related Gene Brpf1 Attenuated Hippocampal Excitatory Synaptic Transmission and Impaired Spatial Learning and Memory Ability

2021 ◽  
Vol 9 ◽  
Author(s):  
Weiwei Xian ◽  
Jingli Cao ◽  
Xiangshan Yuan ◽  
Guoxiang Wang ◽  
Qiuyan Jin ◽  
...  
Keyword(s):  
Intellectual Disability ◽  
Synaptic Transmission ◽  
Learning And Memory ◽  
Spatial Learning ◽  
Hippocampal Neurons ◽  
Dendritic Morphology ◽  
Excitatory Synaptic Transmission ◽  
Spatial Learning And Memory ◽  
Memory Ability ◽  
Cultured Hippocampal Neurons

Patients with monoallelic bromodomain and PHD finger-containing protein 1 (BRPF1) mutations showed intellectual disability. The hippocampus has essential roles in learning and memory. Our previous work indicated that Brpf1 was specifically and strongly expressed in the hippocampus from the perinatal period to adulthood. We hypothesized that mouse Brpf1 plays critical roles in the morphology and function of hippocampal neurons, and its deficiency leads to learning and memory deficits. To test this, we performed immunofluorescence, whole-cell patch clamp, and mRNA-Seq on shBrpf1-infected primary cultured hippocampal neurons to study the effect of Brpf1 knockdown on neuronal morphology, electrophysiological characteristics, and gene regulation. In addition, we performed stereotactic injection into adult mouse hippocampus to knock down Brpf1 in vivo and examined the learning and memory ability by Morris water maze. We found that mild knockdown of Brpf1 reduced mEPSC frequency of cultured hippocampal neurons, before any significant changes of dendritic morphology showed. We also found that Brpf1 mild knockdown in the hippocampus showed a decreasing trend on the spatial learning and memory ability of mice. Finally, mRNA-Seq analyses showed that genes related to learning, memory, and synaptic transmission (such as C1ql1, Gpr17, Htr1d, Glra1, Cxcl10, and Grin2a) were dysregulated upon Brpf1 knockdown. Our results showed that Brpf1 mild knockdown attenuated hippocampal excitatory synaptic transmission and reduced spatial learning and memory ability, which helps explain the symptoms of patients with BRPF1 mutations.

scholarly journals S-adenosylmethionine Decarboxylase 1 Participates in PM2.5 Exposure Induced Neuronal Apoptosis via Mitochondria-Mediated Pathway

2020 ◽  
Author(s):  
Xiaozheng Zhu ◽  
Yikai Shou ◽  
Xintong Ji ◽  
Yu Hu ◽  
Huanhuan Wang
Keyword(s):  
Neurodegenerative Diseases ◽  
Learning And Memory ◽  
Spatial Learning ◽  
Hippocampal Neurons ◽  
Neuronal Apoptosis ◽  
Mitochondrial Pathway ◽  
Whole Body ◽  
Spatial Learning And Memory ◽  
Apoptosis Pathway ◽  
Adenosylmethionine Decarboxylase

Abstract Background: Fine particle (Particulate matter 2.5, PM2.5), as the primary ambient pollutant, is considered harmful to some neurodegenerative diseases, while the specific biochemical mechanism underlying is still unrevealed. Neuronal apoptosis is believed the crucial event in neurodegenerative pathogenesis, but evidence supporting neuronal apoptosis as PM2.5 induced neuronal injury is insufficient. S-adenosylmethionine decarboxylase 1 (AMD1) and its related spermidine synthesis have been shown to participate in cellular apoptosis, but its role in PM2.5 exposure induced neuronal apoptosis was rarely reported. To better understand contribution of AMD1 activity and spermidine in PM2.5 exposure induced neuronal apoptosis, may provide novel therapeutic and preventive targets for air pollution associated neurodegenerative diseases.Methods: In the current work, sixteen C57BL/6 male mice were randomly divided into ambient PM2.5 chamber or filtered air chamber, and the mouse model of whole-body ambient PM2.5 chronic exposure was established. Behavioral and cognitive ability, together with corresponding biomedical index were recorded and tested to evaluated neurotoxicity by PM2.5 exposure in mice. In parallel, PC12 cells and primary hippocampal neurons were applied for PM2.5 treatment to explore the possible cellular and molecular mechanism which may be critically involved in the process. AMD1 activity and cellular spermidine content were modulated by pharmacological approach to examine their participation in PM2.5 triggered neuronal apoptosis, followed by better examination of typical index for mitochondrial membrane potential and mitochondrial-mediated apoptosis pathway signaling.Results: Chronic ambient PM2.5 exposure attenuated spatial learning and memory ability, and triggered neuronal apoptosis together with increased expression of apoptosis-related Bax/Bcl-2 and cleaved caspase-3. PM2.5 exposure impaired AMD1 expression and spermidine synthesis. AMD1 inhibition could mimick PM2.5 exposure induced neuronal apoptosis. Spermidine supplementation rescued against neurotoxicity and inhibited PM2.5 induced apoptosis, in which mitochondrial pathway signaling.Conclusions: Chronic real-time exposure to ambient PM2.5 led to the reduced the ability of spatial learning and memory in mice. Neuronal apoptosis was the key event in the process of neurodegenerative development induced by PM2.5 exposure. AMD1 and spermidine participated in neuronal apoptosis induced by PM2.5 exposure, which was at least partially dependent on mitochondria mediated pathway.

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