ABSTRACT: Sustainedcorrection of hippocampal neurogenic and cognitive deficits after a brief treatment by Nutlin-3 in a mousemodel of Fragile X Syndrome
Project description:Sustainedcorrection of hippocampal neurogenic and cognitive deficits after a brief treatment by Nutlin-3 in a mousemodel of Fragile X Syndrome.
Project description:We found that transient treatment with Nutlin-3 of 2-month-old young adult FMR1-deficient mice prevents the emergence of neurogenic and cognitive deficits in mature adult FXS mice at 6-month of age. We further found that the long-lasting restoration of neurogenesis and cognitive function might not be mediated by changing intrinsic properties of adult neural stem cells. Transcriptomic analysis of the hippocampal tissue demonstrated that transient Nultin-3 treatment leads to significant expression changes in genes related to extracellular matrix, secreted factors, and cell membrane proteins in FMR1-deficient hippocampus
Project description:Neural stem cells residing in the hippocampal neurogenic niche sustain life-long neurogenesis in the adult brain. Adult hippocampal neurogenesis (AHN) is functionally linked to mnemonic and cognitive plasticity in humans and rodents. In Alzheimer’s disease (AD), the process of generating new neurons at the hippocampal neurogenic niche is impeded, yet the mechanisms involved are unknown. Here we identify miR-132, one of the most consistently downregulated microRNAs in AD, as a potent regulator of AHN, exerting cell-autonomous pro-neurogenic effects in the adult neural stem cells and their progeny. Using distinct AD mouse models, cultured human primary and established neural stem cells, and human patient material, we demonstrate that AHN is directly impacted by AD pathology. miR-132 replacement in adult mouse AD hippocampus restores AHN and relevant memory deficits. Our findings corroborate the significance of AHN in AD and reveal the possible therapeutic significance of targeting miR-132 in neurodegeneration.
Project description:TMPyP4 treatment antagonizes cognitive deficits seen in ATR-X model (AtrxΔE2) mice. Our findings suggest a potential therapeutic strategy to target G-quadruplexes and decrease cognitive impairment associated with ATR-X syndrome.
Project description:Fragile X syndrome (FXS), caused by mutations in fragile X mental retardation 1 gene (FMR1), is a prevailing genetic disorder of intellectual disability and autism. Analysis of transcriptome outcome (differentially expressed genes between WT and Fmr1 KO hippocampal neuron) associated with FXS reveal promising value of gene signature-based computation in repurposing drugs for potential practical treatment.
Project description:Fragile X Syndrome (FXS) is the most common cause of inherited intellectual disabilities and the most prevalent monogenic cause of autism. Although the knockout (KO) of the Fmr1 gene homolog in mice is primarily used for elucidating the neurobiological substrate of FXS, there is limited association of the experimental data with the pathophysiological condition in humans. The use of Fmr1 KO rats offers additional translational validity in this regard. Therefore, we employed a multi-level approach to study the behavioral profile and the glutamatergic and GABAergic neurotransmission status in pathophysiology-associated brain structures of Fmr1 KO rats, including the recordings of evoked and spontaneous field potentials from hippocampal slices, paralleled with next-generation RNA sequencing (RNA-seq). We found that these rats exhibit hyperactivity and cognitive deficits, along with characteristic bidirectional glutamatergic and GABAergic alterations in the prefrontal cortex and the hippocampus. These results are coupled to affected excitability and local inhibitory processes in the hippocampus, along with a specific transcriptional profile, highlighting dysregulated hippocampal network activity in KO rats. Overall, our data provide novel insights concerning the biobehavioral profile of FmR1 KO rats and translationally upscales our understanding on pathophysiology and symptomatology of FXS syndrome.
Project description:Patients with Alzheimer’s disease (AD) exhibit progressive memory loss, depression, and anxiety, accompanied by impaired adult hippocampal neurogenesis (AHN). Whether modulating AHN is sufficient to improve these cognitive and noncognitive symptoms in AD remains elusive. Here we report that chronic stimulation of hypothalamic supramammillary nucleus (SuM) during early AD restores AHN in an otherwise impaired neurogenic niche. Strikingly, activation of SuM-enhanced adult-born neurons (ABNs) is sufficient to restore memory and emotion deficits in 5×FAD mice. Interestingly, activation of SuM-enhanced ABNs in AD mice increases CA3 and CA1 activity. To probe ABN-activity-dependent changes, we performed quantitative phosphoproteomics and found activation of SuM-enhanced ABNs promotes activation of the canonical pathways related to synaptic plasticity and microglia phagocytosis. Functional assays further confirm increased CA1 long-term potentiation and enhanced microglia phagocytosis of plaques upon activation of SuM-enhanced ABNs. Our findings reveal a robust AHN-promoting strategy that is sufficient to restore AD-associated deficits and highlight ABN-activity-dependent mechanisms underlying functional improvement in AD.
Project description:Intellectual disability (ID) affects ~2% of the population and ID-associated genes are enriched for epigenetic factors, including those encoding the largest family of histone lysine acetyltransferases (KAT5-KAT8). Among them is KAT6A, whose mutations cause KAT6A Syndrome, with ID as a common clinical feature. However, the underlying molecular mechanism remains unknown. Here, we find that KAT6A deficiency impairs synaptic structure and plasticity in hippocampal CA3, but not in CA1 region, resulting in memory deficits in mice. We further identify a CA3-enriched gene Rspo2, encoding Wnt activator R-spondin 2, as a key transcriptional target of KAT6A. Importantly, deletion of Rspo2 in excitatory neurons impairs memory formation, and restoring RSPO2 expression in CA3 rescues the deficits in Wnt signaling and learning-associated behaviors in Kat6a mutant mice. Collectively, our results demonstrate that KAT6A-RSPO2-Wnt signaling plays a critical role in regulating hippocampal CA3 synaptic plasticity and cognitive function, providing potential therapeutic targets for KAT6A Syndrome and related neurodevelopmental diseases.
Project description:Intellectual disability (ID) affects ~2% of the population and ID-associated genes are enriched for epigenetic factors, including those encoding the largest family of histone lysine acetyltransferases (KAT5-KAT8). Among them is KAT6A, whose mutations cause KAT6A Syndrome, with ID as a common clinical feature. However, the underlying molecular mechanism remains unknown. Here, we find that KAT6A deficiency impairs synaptic structure and plasticity in hippocampal CA3, but not in CA1 region, resulting in memory deficits in mice. We further identify a CA3-enriched gene Rspo2, encoding Wnt activator R-spondin 2, as a key transcriptional target of KAT6A. Importantly, deletion of Rspo2 in excitatory neurons impairs memory formation, and restoring RSPO2 expression in CA3 rescues the deficits in Wnt signaling and learning-associated behaviors in Kat6a mutant mice. Collectively, our results demonstrate that KAT6A-RSPO2-Wnt signaling plays a critical role in regulating hippocampal CA3 synaptic plasticity and cognitive function, providing potential therapeutic targets for KAT6A Syndrome and related neurodevelopmental diseases.
Project description:Heart failure (HF) is associated with an increased risk of cognitive impairment and hippocampal dysfunction, yet the underlying molecular mechanisms remain poorly understood. In this study, we utilized CaMKIIδC transgenic (TG) mice, a model for HF, to investigate the role of microRNA (miRNA) networks in hippocampus-dependent memory recovery. While 3-month-old CaMKIIδC TG mice displayed significant memory deficits and dysregulated hippocampal gene expression, these impairments were no longer detectable at 6 months, despite persistent cardiac dysfunction. Small RNA sequencing revealed a dynamic shift in hippocampal miRNA expression between 3 and 6 months old CaMKIIδC TG mice , with 27 miRNAs, termed "compensatory miRs," targeting 73% of reinstated transcripts and mediating transcriptional homeostasis. Notably, miR-181a-5p emerged as a central hub in the compensatory miRNA network, with its downregulation aligning with restored neuronal function and memory. These findings highlight a synergistic miRNA response that compensates for early transcriptional deficits in HF. In conclusion, our results suggest that better understanding of these microRNA networks may provide novel therapeutic targets to manage heart failure related cognitive dysfunctions.
