ABSTRACT: Inter-individual variation in genes governing human hippocampal progenitor differentiation is associated with hippocampal volume in adulthood
Project description:Analysis of the extent to which inter-individual variation in mRNA decay contributes to inter-individual variation in gene expression levels in humans. The study examines properties of genome-wide decay rates and the relationship between mRNA decay and gene expression across genes, across individuals, and finally across genotype classes.
Project description:Middle cerebral artery occlusion (MCAo) in rat represent the ischemic stroke in human. Rodents subjected to MCAo and treated with venom phospholipase A2 showed reduction in infarct volume after 24hours of stroke. We studied the global gene expression of the reduction in infarct volume using Affymetrix Gene Chips. We analysed all the genes that were up or down regulated in the study. Total RNA isolated from sham, MCAo and MCAo+nPLA rat brains, was pooled to minimize inter-individual variation and hybridized to each array of the RAE-230A or U34A GeneChipTM according to protocols described in the GeneChipTM expression analysis package (Affymetrix, CA).
Project description:Phosphorylation of proteins on serine, threonine, and tyrosine residues is a ubiquitous post-translational modification that plays a key part of essentially every cell signaling process. It is reasonable to assume that inter-individual variation in protein phosphorylation may underlie phenotypic differences, as has been observed for practically any other molecular regulatory phenotype. However, we do not know much about the extent of inter-individual variation in phosphorylation because it is quite challenging to perform a quantitative high throughput study to assess inter-individual variation in any post-translational modification. To test our ability to address this challenge with current technology, we quantified phosphorylation levels for three fully sequenced human cell lines within a nested experimental framework, and found that genetic background is the primary determinant of phosphoproteome variation. We uncovered multiple functional, biophysical, and genetic associations with germline driven phosphopeptide variation (though the small sample size in this ‘pilot’ study limits the applicability of our genetic observations). Among these associations were variants affecting protein levels or structure, with the latter presenting, on average, a stronger effect. Interestingly, we found evidence that is consistent with a phosphopeptide variability buffering effect endowed from properties enriched within longer proteins. We also undertook a thorough technical assessment of our experimental workflow to aid further efforts. Taken together, this work provides the foundation for future work to characterize inter-individual variation in post-translational modification as well as reveals novel insights into the nature of inter-individual variation in phosphorylation.
Project description:Lithium is a first-line treatment for bipolar disorder, where it acts as a mood-stabilizing agent. Although its precise mechanism remains unclear, neuroimaging studies have shown that lithium accumulates in the hippocampus and that chronic use amongst bipolar disorder patients is associated with larger hippocampal volumes. Here, we tested the chronic effects of low (0.75 mM) and high (2.25 mM) doses of lithium on human hippocampal progenitor cells and used immunocytochemistry to investigate the effects of lithium on cell parameters implicated in neurogenesis. Corresponding RNA-sequencing and gene-set enrichment analyses were used to evaluate whether genes affected by lithium in our model overlap with those regulating the volume of specific layers of the dentate gyrus. We observed that high-dose lithium treatment in human hippocampal progenitors increased the generation of neuroblasts (P ≤ 0.01), neurons (P ≤ 0.01), and glia (P ≤ 0.001), alongside the expression of genes which regulate the volume of the molecular layer of the dentate gyrus. This study provides empirical support that adult hippocampal neurogenesis and gliogenesis are mechanisms that could contribute to the effects of lithium on human hippocampal volume.
Project description:Purpose: Determination of inter- and intra-day variations in tear flow rate, tear fluid protein concentration as well as protein composition regarding their impact for future biomarker studies.Methods: Tear fluid was collected non-invasively from 18 healthy subjects performing Schirmer tests at four different time points repetitive in a period of two days. The tear flow rate with Schirmer test strips was measured. Proteins were extracted from strips and quantified using amino acid analysis. Protein composition was analyzed by data-independent (DIA) based mass spectrometry. To exclude any impairments to health, volunteers underwent a detailed neurological as well as an ophthalmological examination.Results: Whether tear fluid was collected from OS or OD did not affect the tear flow rate (p ≈ 0.63) or protein concentration (p ≈ 0.97) of individual subjects. Moreover, protein concentration was independent from the tear volume, so that a change in volume would only have an effect on total protein amount. When the examination days were compared, investigation of tear flow rate (p ≈ 0.001) and protein concentration (p ≈ 0.0003) indicated significant differences. Further mass spectrometric analysis of tear fluid revealed eleven differentially regulated proteins when comparing both examination days. Conclusion: Our findings provide evidence of inter-day variation in tear flow rate, tear proteome concentration and composition in healthy subjects, suggesting that inter-day variation need to be taken into consideration in biomarker research of tear fluid. Identified proteins were assigned to functions in the immune response, oxidative and reducing processes, as well as mannose metabolism.
Project description:We have investigated whether gene expression signatures can be used to predict inter-individual responses to DNA damaging agents We used microarrays to detail inter-individual variation in gene expression across a healthy population under basal and damage induced conditions Keywords: dose (MNNG)
Project description:Identification of genetic polymorphisms associated with inter-individual variation in immune response to Mycobacterium tuberculosis infection.
Project description:Identification of genetic polymorphisms associated with inter-individual variation in immune response to Mycobacterium tuberculosis infection.