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Project description:Early- and late-onset forms of Alzheimer’s disease (AD) share common features that include abnormalities in lipid metabolism, immune response and synaptic function. Of these, the role of lipids remains the least understood. Our study revealed that molecular functions related to Stearoyl-CoA Desaturase (SCD), the rate limiting enzyme in monounsaturated fatty acid synthesis were specifically altered in the hippocampus of 3xTg-AD (a model of early-onset AD). Remarkably, infusion of an SCD inhibitor (SCDi) reversed 40% of altered immune and synapse genes, rescue dendritic spine number and structure, recovered activity-associated immediate-early gene expression and restored learning and memory in 3xTg-AD mice. In addition, we employed single cell RNA sequencing to characterize the cellular landscape of microglia subpopulations within the 3xTg hippocampus and uncovered that SCDi reversed microglial activation and polarization. Together, we show that a single lipid enzyme, SCD, impinges on the core features of AD.
2022-02-25 | GSE167600 | GEO
Project description:Early- and late-onset forms of Alzheimer’s disease (AD) share common features that include abnormalities in lipid metabolism, immune response and synaptic function. Of these, the role of lipids remains the least understood. Our study revealed that molecular functions related to Stearoyl-CoA Desaturase (SCD), the rate limiting enzyme in monounsaturated fatty acid synthesis were specifically altered in the hippocampus of 3xTg-AD (a model of early-onset AD). Remarkably, infusion of an SCD inhibitor (SCDi) reversed 40% of altered immune and synapse genes, rescue dendritic spine number and structure, recovered activity-associated immediate-early gene expression and restored learning and memory in 3xTg-AD mice. In addition, we employed single cell RNA sequencing to characterize the cellular landscape of microglia subpopulations within the 3xTg hippocampus and uncovered that SCDi reversed microglial activation and polarization. Together, we show that a single lipid enzyme, SCD, impinges on the core features of AD.
2022-02-25 | GSE167601 | GEO
Project description:SCD inhibition reverses immune, synaptic and behavioral deficits in an animal model of Alzheimer’s disease
| PRJNA705142 | ENA
Project description:SCD inhibition reverses immune, synaptic and behavioral deficits in an animal model of Alzheimer’s disease [scRNA-Seq]
| PRJNA705117 | ENA
Project description:SCD inhibition reverses immune, synaptic and behavioral deficits in an animal model of Alzheimer’s disease [bulk RNA-Seq]
| PRJNA705144 | ENA
Project description:Background and objectiveStriatal plasticity alterations caused by endoplasmic reticulum (ER) stress is supposed to be critically involved in the mechanism of DYT1 dystonia. In the current study, we expanded this research field by investigating the critical role of ER stress underlying synaptic plasticity impairment imposed by mutant heterozygous Tor1a+/- in a DYT1 dystonia mouse model.MethodsHeterozygous Tor1a+/- mouse model for DYT1 dystonia was established. Wild-type (Tor1a+/+, N=10) and mutant (Tor1a+/-, N=10) mice from post-natal day P25 to P35 were randomly distributed to experimental and control groups. Patch-clamp and current-clamp recordings of SPNs were conducted with intracellular electrodes for electrophysiological analyses. Striatal changes of the direct and indirect pathways were investigated via immunofluorescence. Golgi-Cox staining was conducted to observe spine morphology of SPNs. To quantify postsynaptic signaling proteins in striatum, RNA-Seq, qRT-PCR and WB were performed in striatal tissues.ResultsLong-term depression (LTD) was failed to be induced, while long-term potentiation (LTP) was further strengthened in striatal spiny projection neurons (SPNs) from the Tor1a+/- DYT1 dystonia mice. Spine morphology analyses revealed a significant increase of both number of mushroom type spines and spine width in Tor1a+/- SPNs. In addition, increased AMPA receptor function and the reduction of NMDA/AMPA ratio in the postsynaptic of Tor1a+/- SPNs was observed, along with increased ER stress protein levels in striatum of Tor1a+/- DYT1 dystonia mice. Notably, ER stress inhibitors, tauroursodeoxycholic acid (TUDCA), could rescue LTD as well as AMPA currents.ConclusionThe current study illustrated the role of ER stress in mediating structural and functional plasticity alterations in Tor1a+/- SPNs. Inhibition of the ER stress by TUDCA is beneficial in reversing the deficits at the cellular and molecular levels. Remedy of dystonia associated neurological and motor functional impairment by ER stress inhibitors could be a recommendable therapeutic agent in clinical practice.
| S-EPMC8436893 | biostudies-literature
Project description:Traumatic brain injury (TBI) causes extensive neural damage, often resulting in long-term cognitive impairments. Unfortunately, effective treatments for TBI remain elusive. The RhoA-ROCK signaling pathway is a potential therapeutic target since it is activated by TBI and can promote the retraction of dendritic spines/synapses, which are critical for information processing and memory storage. To test this hypothesis, RhoA-ROCK signaling was blocked by RhoA deletion from postnatal neurons or treatment with the ROCK inhibitor fasudil. We found that TBI impairs both motor and cognitive performance and inhibiting RhoA-ROCK signaling alleviates these deficits. Moreover, RhoA-ROCK inhibition prevents TBI-induced spine remodeling and mature spine loss. These data argue that TBI elicits pathological spine remodeling that contributes to behavioral deficits by altering synaptic connections, and RhoA-ROCK inhibition enhances functional recovery by blocking this detrimental effect. As fasudil has been safely used in humans, our results suggest that it could be repurposed to treat TBI.
| S-EPMC5587534 | biostudies-literature
Project description:Alzheimer's disease (AD) is a progressive neurodegenerative disorder for which numerous mouse models have been generated. In both AD patients and mouse models, there is increasing evidence that neuronal dysfunction occurs before the accumulation of beta-amyloid (Abeta)-containing plaques and neurodegeneration. Characterization of the timing and nature of preplaque dysfunction is important for understanding the progression of this disease and to identify pathways and molecular targets for therapeutic intervention. Hence, we have examined the progression of dysfunction at the morphological, functional, and behavioral levels in the Tg2576 mouse model of AD. Our data show that decreased dendritic spine density, impaired long-term potentiation (LTP), and behavioral deficits occurred months before plaque deposition, which was first detectable at 18 months of age. We detected a decrease in spine density in the outer molecular layer of the dentate gyrus (DG) beginning as early as 4 months of age. Furthermore, by 5 months, there was a decline in LTP in the DG after perforant path stimulation and impairment in contextual fear conditioning. Moreover, an increase in the Abeta42/Abeta40 ratio was first observed at these early ages. However, total amyloid levels did not significantly increase until approximately 18 months of age, at which time significant increases in reactive astrocytes and microglia could be observed. Overall, these data show that the perforant path input from the entorhinal cortex to the DG is compromised both structurally and functionally, and this pathology is manifested in memory defects long before significant plaque deposition.
| S-EPMC1405622 | biostudies-literature
Project description:Maternal immune activation (MIA) has been identified as a significant risk factor for several neurodevelopmental disorders. We have previously demonstrated that postpubertal environmental enrichment (EE) rescues and promotes resiliency against MIA in male rats. Importantly, EE protocols have demonstrated clinical relevancy in human rehabilitation settings. Applying some of the elements of these EE protocols (e.g. social, physical, cognitive stimulation) to animal models of health and disease allows for the exploration of the mechanisms that underlie their success. Here, using a MIA model, we further investigate the rehabilitative potential of complex environments with a focus on female animals. Additionally, we expand upon some of our previous work by exploring genetic markers of synaptic plasticity and stress throughout several brain regions of both sexes. In the current study, standard housed female Sprague-Dawley rats were challenged with either the inflammatory endotoxin lipopolysaccharide (LPS; 100 μg/kg) or saline (equivolume) on gestational day 15. On postnatal day 50, male and female offspring were randomized into one of three conditions that differed in terms of cage size, number of cage mates (social stimulation) and enrichment materials. Spatial discrimination ability and social behavior were assessed six weeks later. Similar to our previously published work in males, our results revealed that a single LPS injection during mid gestation disrupted spatial discrimination ability in female rats. Postpubertal EE rescued this disruption. On the endocrine level, EE dampened elevations in plasma corticosterone that followed MIA, which may mediate EE's rehabilitative effects in female offspring. Within the prefrontal cortex, hippocampus, amygdala, and hypothalamus, MIA and EE altered the mRNA expression of several genes associated with resiliency and synaptic plasticity in both sexes. Overall, our findings provide further evidence that EE may serve as a therapeutic intervention for MIA-induced behavioral and cognitive deficits. Moreover, we identify some sexually dimorphic molecular mechanisms that may underlie these impairments and their rescue.
| S-EPMC7197879 | biostudies-literature
Project description:In light of the rising prevalence of Alzheimer's disease (AD), new strategies to prevent, halt, and reverse this condition are needed urgently. Perturbations of brain network activity are observed in AD patients and in conditions that increase the risk of developing AD, suggesting that aberrant network activity might contribute to AD-related cognitive decline. Human amyloid precursor protein (hAPP) transgenic mice simulate key aspects of AD, including pathologically elevated levels of amyloid-? peptides in brain, aberrant neural network activity, remodeling of hippocampal circuits, synaptic deficits, and behavioral abnormalities. Whether these alterations are linked in a causal chain remains unknown. To explore whether hAPP/amyloid-?-induced aberrant network activity contributes to synaptic and cognitive deficits, we treated hAPP mice with different antiepileptic drugs. Among the drugs tested, only levetiracetam (LEV) effectively reduced abnormal spike activity detected by electroencephalography. Chronic treatment with LEV also reversed hippocampal remodeling, behavioral abnormalities, synaptic dysfunction, and deficits in learning and memory in hAPP mice. Our findings support the hypothesis that aberrant network activity contributes causally to synaptic and cognitive deficits in hAPP mice. LEV might also help ameliorate related abnormalities in people who have or are at risk for AD.
| S-EPMC3479491 | biostudies-literature