Several omics data such as genomics and transcriptomics, have been available for several tissues, including the blood. Now, for the first time we have access to the proteome of human blood.
This is the age of 'omics', wherein omics refers to a systems-oriented approach. Some of the well-established omics data with regards to the blood tissue, include genomics and transcriptomics. High volumes of data could be generated due to advent of chip technology, which ensured both high throughput and reduced cost. Proteomics however, did not make the cut due to the technical challenges. A large collaborative effort, spanning two continents has now grabbed the bull by its horns published the first draft of the human proteome.
The scientists mapped the proteome of several human tissues, including blood by generating a high quality mass spectrometry data set. They studied 30 different histologically normal tissue types, 6 of which belonged to blood. Knowledge of the blood proteome is crucial to understand how the different hematopoietic cells respond to varied stimuli and conditions. We have previously discussed in a previous blog how changes in the rate of protein synthesis may cause undesirable changes in the quality and/or content of the hematopoietic stem cell proteome.
The six types of blood cells studied are: platelets, monocytes, CD4+ T cells, CD8+, T cells, NK cells and B cells. Lymphocytes in blood were isolated from leukopaks obtained from at least 3 healthy volunteers participating in routine platelet apheresis. Individual populations in the order of monocytes, NK cells, B cells, CD8+ T cells and CD4+ T cells were sequentially isolated using magenetic beads. Platelets were obtained from platelet rich plasma. The samples were then fractionated, digested and analysed on the high-resolution and high accuracy Orbitrap mass analyser. This high quality data was compared with PeptideAtlas and GPMDB, two of the largest human peptide-based resources.
Of the estimated 20,500 proteins in the human body, the scientists profiled around 17,294, accounting for around 84% of the total proteins. Further, they traced around 2,500 of 3,000 proteins that had been categorized as 'missing proteins' and discovered 193 new proteins. The mass spectrometry data also revealed tissue specific protein isoforms, such as FYN isoform 1 in brain and isoform 2 in hematopoietic cells.
To summarize, this recent study which has mapped the human blood proteome for the first time, can hasten our understanding of how and why the blood tissue functions in a particular way in a normal or diseased person. HemaCare is an established and leading source of a variety of blood products from both normal individuals and diseased patients, which can be employed for advanced biomedical research and cell therapy.
1: Min-Sik Kim et al. A draft map of the human proteome. Nature (2014) 509: 575-581.