Project description:In Alzheimer's disease (AD), early deficits in learning and memory are a consequence of synaptic modification which are likely induced by toxic beta-amyloid oligomers (dAbeta). To identify molecular targets downstream of dAbeta binding we prepared synaptoneurosomes from frontal cortex of control and IAD patients, and isolated mRNAs for comparison of gene expression. This approach elevated synaptic mRNAs above the threshold necessary for expression changes to be discriminated and also reduced other cellular mRNAs. In patients with minimal cognitive impairment (MCI) termed incipient AD (IAD) global measures of cognition declined with increasing levels of dimeric beta (dAbeta). These patients also showed increased expression of neuroplasticity related genes, many encoding 3' UTR consensus sequences that regulate local translation in the synapse. One such gene, GluR2, displayed elevated mRNA and protein expression in IAD. Other neurotransmitter-related genes were also upregulated. Overexpressed genes may induce compensatory as well as negative effects on cognition and provide targets for intervention to moderate the response to dAbeta. Experiment Overall Design: Patient information Experiment Overall Design: CNS tissues were obtained from the USC Alzheimer's Disease Research Center (ADRC) Neuropathology Core, NIA AG05142. Clinical information, including neurological examination, neuropsychological testing such as cognitive assessment, family history, and medications were provided by the USC ADRC Clinical Core. The groups did not differ significantly in age or years of education. Medication histories indicated one IAD patient had used a selective serotonin uptake inhibitor. Post-mortem interval (PMI) ranged from 2 to 9 hours (mean 5.1 hrs.). The study included 8 normal controls and 6 patients with Incipient Alzheimer's Disease. Experiment Overall Design: To augment studies comparing homogenates of control to AD brains, we used synaptoneurosome preparations to enrich for synaptic mRNAs. Synaptoneurosomes were prepared from the prefrontal cortices of control and IAD patients by a simple, rapid, but gentle method using sequential mesh screens.
Project description:In Alzheimer’s disease (AD), early deficits in learning and memory are a consequence of synaptic modification which are likely induced by toxic beta-amyloid oligomers (oAβ). To identify molecular targets downstream of oAβ binding we prepared synaptoneurosomes from frontal cortex of control and IAD patients, and isolated mRNAs for comparison of gene expression. This approach elevated synaptic mRNAs above the threshold necessary for expression changes to be discriminated and also reduced other cellular mRNAs. In patients with minimal cognitive impairment (MCI) termed incipient AD (IAD) global measures of cognition declined with increasing levels of dimeric Aβ (dAβ). These patients also showed increased expression of neuroplasticity related genes, many encoding 3' UTR consensus sequences that regulate local translation in the synapse. One such gene, GluR2, displayed elevated mRNA and protein expression in IAD. Other neurotransmitter-related genes were also upregulated. Overexpressed genes may induce compensatory as well as negative effects on cognition and provide targets for intervention to moderate the response to dAβ.
Project description:Gene expression profiling of immortalized human mesenchymal stem cells with hTERT/E6/E7 transfected MSCs. hTERT may change gene expression in MSCs. Goal was to determine the gene expressions of immortalized MSCs.
Project description:Kynureninase is a member of a large family of catalytically diverse but structurally homologous pyridoxal 5'-phosphate (PLP) dependent enzymes known as the aspartate aminotransferase superfamily or alpha-family. The Homo sapiens and other eukaryotic constitutive kynureninases preferentially catalyze the hydrolytic cleavage of 3-hydroxy-l-kynurenine to produce 3-hydroxyanthranilate and l-alanine, while l-kynurenine is the substrate of many prokaryotic inducible kynureninases. The human enzyme was cloned with an N-terminal hexahistidine tag, expressed, and purified from a bacterial expression system using Ni metal ion affinity chromatography. Kinetic characterization of the recombinant enzyme reveals classic Michaelis-Menten behavior, with a Km of 28.3 +/- 1.9 microM and a specific activity of 1.75 micromol min-1 mg-1 for 3-hydroxy-dl-kynurenine. Crystals of recombinant kynureninase that diffracted to 2.0 A were obtained, and the atomic structure of the PLP-bound holoenzyme was determined by molecular replacement using the Pseudomonas fluorescens kynureninase structure (PDB entry 1qz9) as the phasing model. A structural superposition with the P. fluorescens kynureninase revealed that these two structures resemble the "open" and "closed" conformations of aspartate aminotransferase. The comparison illustrates the dynamic nature of these proteins' small domains and reveals a role for Arg-434 similar to its role in other AAT alpha-family members. Docking of 3-hydroxy-l-kynurenine into the human kynureninase active site suggests that Asn-333 and His-102 are involved in substrate binding and molecular discrimination between inducible and constitutive kynureninase substrates.
Project description:As the evolution of miRNA genes has been found to be one of the important factors in formation of the modern type of man, we performed a comparative analysis of the evolution of miRNA genes in two archaic hominines, Homo sapiens neanderthalensis and Homo sapiens denisova, and elucidated the expression of their target mRNAs in bain.A comparative analysis of the genomes of primates, including species in the genus Homo, identified a group of miRNA genes having fixed substitutions with important implications for the evolution of Homo sapiens neanderthalensis and Homo sapiens denisova. The mRNAs targeted by miRNAs with mutations specific for Homo sapiens denisova exhibited enhanced expression during postnatal brain development in modern humans. By contrast, the expression of mRNAs targeted by miRNAs bearing variations specific for Homo sapiens neanderthalensis was shown to be enhanced in prenatal brain development.Our results highlight the importance of changes in miRNA gene sequences in the course of Homo sapiens denisova and Homo sapiens neanderthalensis evolution. The genetic alterations of miRNAs regulating the spatiotemporal expression of multiple genes in the prenatal and postnatal brain may contribute to the progressive evolution of brain function, which is consistent with the observations of fine technical and typological properties of tools and decorative items reported from archaeological Denisovan sites. The data also suggest that differential spatial-temporal regulation of gene products promoted by the subspecies-specific mutations in the miRNA genes might have occurred in the brains of Homo sapiens denisova and Homo sapiens neanderthalensis, potentially contributing to the cultural differences between these two archaic hominines.
Project description:For these data, we analyzed hippocampal gene expression of nine control and 22 AD subjects of varying severity on 31 separate microarrays. We then tested the correlation of each gene's expression with MiniMental Status Examination (MMSE) and neurofibrillary tangle (NFT) scores across all 31 subjects regardless of diagnosis. These tests revealed a major transcriptional response comprising thousands of genes significantly correlated with AD markers. Several hundred of these genes were also correlated with AD markers across only control and incipient AD subjects (MMSE > 20). Keywords = bioinformatics Keywords = gene expression Keywords = memory Keywords = synaptic plasticity Keywords = myelin Keywords = inflamation Keywords = aging Keywords = behavior Keywords = Alzheimer's Keywords = microarray Keywords: repeat sample
Project description:PurposeWe investigated the evidence of recent positive selection in the human phototransduction system at single nucleotide polymorphism (SNP) and gene level.MethodsSNP genotyping data from the International HapMap Project for European, Eastern Asian, and African populations was used to discover differences in haplotype length and allele frequency between these populations. Numeric selection metrics were computed for each SNP and aggregated into gene-level metrics to measure evidence of recent positive selection. The level of recent positive selection in phototransduction genes was evaluated and compared to a set of genes shown previously to be under recent selection, and a set of highly conserved genes as positive and negative controls, respectively.ResultsSix of 20 phototransduction genes evaluated had gene-level selection metrics above the 90th percentile: RGS9, GNB1, RHO, PDE6G, GNAT1, and SLC24A1. The selection signal across these genes was found to be of similar magnitude to the positive control genes and much greater than the negative control genes.ConclusionsThere is evidence for selective pressure in the genes involved in retinal phototransduction, and traces of this selective pressure can be demonstrated using SNP-level and gene-level metrics of allelic variation. We hypothesize that the selective pressure on these genes was related to their role in low light vision and retinal adaptation to ambient light changes. Uncovering the underlying genetics of evolutionary adaptations in phototransduction not only allows greater understanding of vision and visual diseases, but also the development of patient-specific diagnostic and intervention strategies.
Project description:The master epigenetic regulator lysine acetyltransferase (KAT) p300/CBP plays a pivotal role in neuroplasticity and cognitive functions. Recent evidence has shown that in several neurodegenerative diseases, including Alzheimer’s disease (AD), the expression level and function of p300/CBP are severely compromised, leading to altered gene expression causing pathological conditions. Here, we show that p300/CBP activation by a small molecule TTK21, conjugated to carbon nanosphere (CSP) ameliorates Aβ-impaired long-term potentiation (LTP) induced by high frequency stimulation, theta burst stimulation and synaptic tagging/capture (STC). This functional rescue was correlated with CSP-TTK21induced changes in transcription and translation. Mechanistically, we observed that the expression of a large number of synaptic plasticity- and memory-related genes was rescued, presumably by the restoration of p300/CBP mediated acetylation. Collectively, these results suggest that small molecule activators of p300/CBP could be a potential therapeutic molecule for neurodegenerative diseases like AD
Project description:Transcriptional profiling of human mesenchymal stem cells comparing normoxic MSCs cells with hypoxic MSCs cells. Hypoxia may inhibit senescence of MSCs during expansion. Goal was to determine the effects of hypoxia on global MSCs gene expression.