Biology subjects

Hallstrom, B. M.

Publications and source records attributed to Hallstrom, B. M..

3 recordsLinked to original sources

bioRxiv2019

A systems-based map of human brain cell-type enriched genes and malignancy-associated endothelial changes

Changes in the endothelium of the cerebral vasculature can contribute to inflammatory, thrombotic and malignant disorders. The importance of defining cell type-specific genes and how they are modified in disease is increasingly recognised. Here, we developed a bioinformatics-based approach to identify normal brain cell-enriched genes, using bulk RNAseq data from 238 normal human cortex samples from 2 independent cohorts. We compared endothelial cell-enriched gene profiles with astrocyte, oligodendrocyte and neuron profiles. Global modifications to the endothelium in malignant disease were characterised, using RNAseq data from 516 human lower grade gliomas and 401 human glioblastoma multiforme samples. Lower grade glioma appeared to be an endothelial intermediate between normal brain and glioblastoma multiforme. We identify the most highly glioblastoma multiforme-specific endothelial cell biomarkers, providing potential diagnostic or therapeutic targets. In summary, we provide a roadmap of endothelial cell identity in normal and malignant brain tissue, using a bioinformatics-based method developed to resolve bulk RNAseq datasets into constituent cell type-enriched profiles.

cell biology↗

bioRxiv2018

Quantification and discovery of sequence determinants of protein per mRNA amount in 29 human tissues

Despite their importance in determining protein abundance, a comprehensive catalogue of sequence features controlling protein-to-mRNA (PTR) ratios and a quantification of their effects is still lacking. Here we quantified PTR ratios for 11,575 proteins across 29 human tissues using matched transcriptomes and proteomes. We analyzed the contribution of known sequence determinants of protein synthesis and degradation and 15 novel mRNA and protein sequence motifs that we found by association testing. While the dynamic range of PTR ratios spans more than 2 orders of magnitude, our integrative model predicts PTR ratios at a median precision of 3.2-fold. A reporter assay provided significant functional support for two novel UTR motifs and a proteome-wide competition-binding assay identified motif-specific bound proteins for one motif. Moreover, our direct comparison of protein to RNA levels led to a new metrics of codon optimality. Altogether, this study shows that a large fraction of PTR ratio variance across genes can be predicted from sequence and identified many new candidate post-transcriptional regulatory elements in the human genome.

systems biology↗

bioRxiv2018

A deep proteome and transcriptome abundance atlas of 29 healthy human tissues

Genome-, transcriptome- and proteome-wide measurements provide valuable insights into how biological systems are regulated. However, even fundamental aspects relating to which human proteins exist, where they are expressed and in which quantities are not fully understood. Therefore, we have generated a systematic, quantitative and deep proteome and transcriptome abundance atlas from 29 paired healthy human tissues from the Human Protein Atlas Project and representing human genes by 17,615 transcripts and 13,664 proteins. The analysis revealed that few proteins show truly tissue-specific expression, that vast differences between mRNA and protein quantities within and across tissues exist and that the expression levels of proteins are often more stable across tissues than those of transcripts. In addition, only ~2% of all exome and ~7% of all mRNA variants could be confidently detected at the protein level showing that proteogenomics remains challenging, requires rigorous validation using synthetic peptides and needs more sophisticated computational methods. Many uses of this resource can be envisaged ranging from the study of gene/protein expression regulation to protein biomarker specificity evaluation to name a few.

systems biology↗