Project description:The purpose of this study was to determine the effect of peripheral (IV) administration of AβPP antisense on hippocampal gene expression as well as on learning and memory as measured by T-maze in adult male mice aged 12 months. The AβPP antisense treatment reversed learning and memory deficits and altered the expression of 944 hippocampal genes, which are involved in a coordinated set of signaling pathways. Expression and pathway findings were verified at the protein and functional (phosphorylation) levels. Global differential profiling of hippocampal gene expression (12 month old adult mice: Control, SAMP8, SAMP8 + Random antisense, SAMP8 + AβPP antisense) was performed using Affymetrix GeneChip® Mouse Genome 430 2.0 Arrays. The AβPP antisense reversed the memory deficits and altered expression of 944 hippocampal genes. Pathway analysis showed significant gene expression changes in 9 pathways. These include the MAPK signaling pathway (P = 0.0078) and the phosphatidylinositol signaling pathway (P = 0.043), which we have previously shown to be altered in SAMP8 mice. The changes in these pathways contributed to significant changes in the Neurotropin (P = 0.0083) and Insulin Signaling (P = 0.015) pathways, which are known to be important in learning and memory. Changes in these pathways were accompanied by phosphorylation changes in the downstream target proteins p70S6K, GSK3β, ERK, and CREB. These changes in hippocampal gene expression and protein phosphorylation may suggest specific new targets for antisense therapy aimed at improving memory. One-way ANOVA (4 conditions, n=4). Variables were treatment (AβPP antisense, Random antisense, no treatment) and mouse strain (Control and SAMP8). This results in 4 groups: (All 12-month-old adult male mice) NT-Control, NT_SAMP8, Random_AS-SAMP8, and AβPP_AS-SAMP8. Each group had 4 biological replicates (4 mice). The 'Control' mice were a 50% backcross of the SAMP8 mice with CD-1 mice (50% SAMP8 mice). These mice were closely related to SAMP8 mice but exhibited no memory deficits at 4 or 12 months. The SAMP8 mice had memory deficits at 12 months but not at 4 months.
Project description:The purpose of this study was to determine the effect of peripheral (IV) administration of AβPP antisense on hippocampal gene expression as well as on learning and memory as measured by T-maze in adult male mice aged 12 months. The AβPP antisense treatment reversed learning and memory deficits and altered the expression of 944 hippocampal genes, which are involved in a coordinated set of signaling pathways. Expression and pathway findings were verified at the protein and functional (phosphorylation) levels. Global differential profiling of hippocampal gene expression (12 month old adult mice: Control, SAMP8, SAMP8 + Random antisense, SAMP8 + AβPP antisense) was performed using Affymetrix GeneChip® Mouse Genome 430 2.0 Arrays. The AβPP antisense reversed the memory deficits and altered expression of 944 hippocampal genes. Pathway analysis showed significant gene expression changes in 9 pathways. These include the MAPK signaling pathway (P = 0.0078) and the phosphatidylinositol signaling pathway (P = 0.043), which we have previously shown to be altered in SAMP8 mice. The changes in these pathways contributed to significant changes in the Neurotropin (P = 0.0083) and Insulin Signaling (P = 0.015) pathways, which are known to be important in learning and memory. Changes in these pathways were accompanied by phosphorylation changes in the downstream target proteins p70S6K, GSK3β, ERK, and CREB. These changes in hippocampal gene expression and protein phosphorylation may suggest specific new targets for antisense therapy aimed at improving memory.
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:Epidemiological studies suggest that consumption of caffeine, the most commonly consumed psychoactive substances found in coffee, tea or soft drinks reduces the risk of developing Alzheimer’s disease (AD). While previous studies employing transgenic AD mouse models reported on reduced amyloid plaque load or an amelioration of behavioral deficits, there is only limited information on its potential effects on neurodegeneration. In the current study, we assessed whether long-term caffeine consumption affects hippocampal neuron loss and associated behavioral deficits in the Tg4-42 mouse model of AD. Treatment over a 4 months period reduced hippocampal neuron loss, rescued learning and memory deficits and ameliorates impaired neurogenesis. Neuron-specific hippocampal transcriptome analysis revealed an altered expression profile with an up-regulation of genes linked to synaptic function and processes, as well as neural progenitor proliferation. Treatment of 5xFAD mice with the same paradigm also rescued behavioral deficits, however, without affecting extracellular amyloid-beta (Abeta) levels or altered APP processing.
Project description:We investigated the long-term therapeutic effects of oral administration of a brain-penetrant HDAC1/3 inhibitor RG2833 in a Fisher transgenic 344-AD (TgF344-AD) rats model of AD. We treated for 6 months, starting at 5 months of age administering the drug in rodent chow at ~30mg/kg of body weight. After treatment we performed experiements to show the effects of drug treatment on spatial memory deficits. We show significantly improved hippocampal-dependent spatial memory performance in TgF344-AD female.
Project description:Introgressed variants from other species can be an important source of genetic variation because they may arise rapidly, can include multiple mutations on a single haplotype, and have often been pretested by selection in the species of origin. Although introgressed alleles are generally deleterious, several studies have reported introgression as the source of adaptive alleles-including the rodenticide-resistant variant of Vkorc1 that introgressed from Mus spretus into European populations of Mus musculus domesticus. Here, we conducted bidirectional genome scans to characterize introgressed regions into one wild population of M. spretus from Spain and three wild populations of M. m. domesticus from France, Germany, and Iran. Despite the fact that these species show considerable intrinsic postzygotic reproductive isolation, introgression was observed in all individuals, including in the M. musculus reference genome (GRCm38). Mus spretus individuals had a greater proportion of introgression compared with M. m. domesticus, and within M. m. domesticus, the proportion of introgression decreased with geographic distance from the area of sympatry. Introgression was observed on all autosomes for both species, but not on the X-chromosome in M. m. domesticus, consistent with known X-linked hybrid sterility and inviability genes that have been mapped to the M. spretus X-chromosome. Tract lengths were generally short with a few outliers of up to 2.7 Mb. Interestingly, the longest introgressed tracts were in olfactory receptor regions, and introgressed tracts were significantly enriched for olfactory receptor genes in both species, suggesting that introgression may be a source of functional novelty even between species with high barriers to gene flow.
Project description:PURPOSE: To provide a detailed gene expression profile of the normal postnatal mouse cornea. METHODS: Serial analysis of gene expression (SAGE) was performed on postnatal day (PN)9 and adult mouse (6 week) total corneas. The expression of selected genes was analyzed by in situ hybridization. RESULTS: A total of 64,272 PN9 and 62,206 adult tags were sequenced. Mouse corneal transcriptomes are composed of at least 19,544 and 18,509 unique mRNAs, respectively. One third of the unique tags were expressed at both stages, whereas a third was identified exclusively in PN9 or adult corneas. Three hundred thirty-four PN9 and 339 adult tags were enriched more than fivefold over other published nonocular libraries. Abundant transcripts were associated with metabolic functions, redox activities, and barrier integrity. Three members of the Ly-6/uPAR family whose functions are unknown in the cornea constitute more than 1% of the total mRNA. Aquaporin 5, epithelial membrane protein and glutathione-S-transferase (GST) omega-1, and GST alpha-4 mRNAs were preferentially expressed in distinct corneal epithelial layers, providing new markers for stratification. More than 200 tags were differentially expressed, of which 25 mediate transcription. CONCLUSIONS: In addition to providing a detailed profile of expressed genes in the PN9 and mature mouse cornea, the present SAGE data demonstrate dynamic changes in gene expression after eye opening and provide new probes for exploring corneal epithelial cell stratification, development, and function and for exploring the intricate relationship between programmed and environmentally induced gene expression in the cornea. Keywords: other
Project description:We collected whole genome testis expression data from hybrid zone mice. We integrated GWAS mapping of testis expression traits and low testis weight to gain insight into the genetic basis of hybrid male sterility.
Project description:Engrams are considered to be substrates for memory storage, and the functional dysregulation of the engrams leads to cognition impairment.However, the cellular basis for these maladaptive changes lead to the forgetting of memories remains unclear. Here we found that the expression of autophagy protein 7 (Atg7) mRNA was dramatically upregulated in aged DG engrams, and led to the forgetting of contextual fear memory and the activation of surrounding microglia.To determine mechanism by which autophagy in DG engrams activates the surrounding microglia, mice were co-injected AAV-RAM-Cre either with AAV-Dio-Atg7-Flag or AAV-Dio- EYFP in dorsal dentate gyrus to overexpress ATG7 in the DG memory engrams. Microglia were separated using magnetic-activated cell sorting and subjected to RNA-Seq in dorsal hippocampus .Bioinformatics analysis shown overexpression of Atg7 in dorsal DG memory engrams caused an increase in the expression of Tlr2 in the surrounding microglia.Depletion of Toll-like receptor 2/4 (TLR2/4) in DG microglia prohibited excessive microglial activation and synapse elimination induced by the overexpression of ATG7 in DG engrams, and thus prevented forgetting. Furthermore, the expression of Rac1, a Rho-GTPases which regulates active forgetting in both fly and mice, was upregulated in aged engrams. Optogentic activation of Rac1 in DG engrams promoted the autophagy of the engrams, the activation of microglia, and the forgetting of fear memory. Invention of the Atg7 expression and microglia activation attenuated forgetting induced by activation of Rac1 in DG engrams. Together, our findings revealed autophagy-dependent synapse elimination of DG engrams by microglia as a novel forgetting mechanism.