In Silico Analyses of Proteomic Data Suggest a Role for Heat Shock Proteins in Umbilical Cord Blood Hematopoietic Stem Cells

Abstract

Umbilical-cord blood (UCB) has growingly become an accepted alternative source of hematopoietic stem cells for transplantation purposes. However, the low cell dose limit within a single unit is still an obstacle hindering the way of a broader diffusion. The real deal is the lack of knowledge about the molecular processes governing the events of expansion and differentiation of these cells. In order to fill this void, several studies were focused on the identification of the peculiar whole protein profile of UCB-derived hematopoietic stem cells. In this review article we provide a referenced list of overall proteins from UCB-derived hematopoietic stem and progenitor cells. This list has been elaborated for pathway and network analyses, along with GO term enrichment for biological and molecular functions, in order to individuate main classes of proteins governing functioning of these cells. From these analyses it seems to emerge a central role for heat shock proteins in immature hematopoietic stem cells. Their role might be relevant in protecting crucial transcription factors which drive proliferation and differentiation towards a specific lineage (e.g. erythroid, myeloid). Hereby we also stress the helpfulness of interactomics elaboration in providing a unified overview of independent proteomics data. It appears that maturation, other than representing a bottleneck to protein expression, could sculpt interaction maps via reducing complexity of immature interactomics profiles.

Proteomic Profiling ofEx VivoExpanded CD34-Positive Haematopoetic Cells Derived from Umbilical Cord Blood

“…This is—to our knowledge—by now the most detailed view on protein level for these cells along ex vivo expansion time of seven days. Of 290 proteins described by [12] in native CD34 + cells we confirmed 221 proteins. Label-free quantification of 1343 proteins indicates major changes in the proteome along the expansion time.…”

“…However, in spite of its potential, only few studies applied proteomics to obtain insights into biological processes within cord-blood-derived CD34 + cells [7–12]. With a broad spectrum of different techniques, analysis of cell lysate led to the identification of up to 370 proteins [10] in native CD34 + cord blood cells.…”

Role of Heat Shock Proteins in Stem Cell Behavior

“…68 Accordingly, Hsps could also be involved in differentiation events of umbilical cord blood-derived HSCs. 69 Together, these studies suggest that Hsp might represent a key target either for future investigations or for approaches addressing mechanisms underlying the induction of SC proliferation and modulation of their differentiation events.…”