Low oxygen tension reveals distinctHOXcodes in human cord blood-derived stromal cells associated with specific endochondral ossification capacitiesin vitroandin vivo

Abstract

Effects of oxygen tension on the generation, expansion, proliferation and differentiation of stromal cell types is widely described in the literature. However, data on the internal heterogeneity of applied cell populations at different O levels and possible impacts on differentiation potentials are controversial. Here, the expression of 39 human HOX genes was determined in neonatal cord blood stromal cells and linked to differentiation-associated signatures. In cord blood, unrestricted somatic stromal cells (USSCs), lacking HOX gene expression, and cord blood-derived multipotent stromal cells (CB-MSCs), expressing about 20 HOX genes, are distinguished by their specific HOX code. Interestingly, 74% of the clones generated at 21% O were HOX-negative USSCs, whereas 73% of upcoming clones at 3% O were HOX-positive CB-MSCs. In order to better categorize distinct cell lines generated at 3% O , the expression of all 39 HOX genes within HOX clusters A, B, C and D were tested and new subtypes defined: cells negative in all four HOX clusters (USSCs); cells positive in all four clusters (CB-MSCs ); and subpopulations missing a single cluster (CB-MSCs and CB-MSCs ). Comprehensive qPCR analyses of established chondro-osteomarkers revealed subtype-specific signatures verifiably associated with in vitro and in vivo differentiation capacity. The data presented here underline the necessity of better characterizing distinct cell populations at a clonal level, taking advantage of the inherent specific HOX code as a distinguishing feature between individual subtypes. Moreover, the correlation of subtype-specific molecular signatures with in vitro and in vivo bone formation is discussed. Copyright © 2016 John Wiley & Sons, Ltd.

Human umbilical cord blood-borne fibroblasts contain marrow niche precursors that form a bone/marrow organoid in vivo

“…In vitro, CB-BFs display osteogenic and chondrogenic differentiation potential , whereas they have a reduced or virtually absent capacity to generate adipocyte-like cells (Kern et al, 2006;Goodwin et al, 2001;Zhang et al, 2011;Bieback et al, 2008;Karagianni et al, 2013). When transplanted in vivo with osteoconductive ceramic scaffolds, CB-BFs are able to form histology-proven bone (Zhang et al, 2011;Liedtke et al, 2016;Sacchetti et al, 2016). Interestingly, we have also demonstrated that CB-BFs consistently form cartilage in open heterotopic transplants, a property that is usually not observed in BMSCs.…”

No Identical “Mesenchymal Stem Cells” at Different Times and Sites: Human Committed Progenitors of Distinct Origin and Differentiation Potential Are Incorporated as Adventitial Cells in Microvessels

“…By gauging their native differentiation potential with a variety of stringent differentiation assays, we demonstrated that human BM CD146 + cells are inherently geared to generate bone and BM stroma that support hematopoiesis and include adipocytes, but are not myogenic, and are not spontaneously chondrogenic in vivo; MU “MSCs” with an identical cell-surface phenotype are not inherently skeletogenic, and are inherently myogenic; and CB “MSCs” are not myogenic, but are chondro-osteoprogenitors most likely due to their fetal origin ( Bianco and Robey, 2015 ) and are the only kind of human “MSCs” ever shown to actually form cartilage consistently in open heterotopic transplants in vivo, independent of any ex vivo induction to cartilage differentiation as applied in the widely used pellet culture assay. CB cells are unlike other cells that are found in the umbilical cord, based on their cell-surface markers, their ability to differentiate into adipocytes and cartilage, and expression of associated markers, and they have a distinct expression pattern of HOX genes compared with other umbilical cord derivatives ( Bosch et al., 2012 , Liedtke et al., 2010 , Liedtke et al., 2016 ). BM- and MU-derived clonogenic progenitors of mesoderm derivatives are associated with BV walls in situ and include cells in a position characteristic of mural cells/pericytes, but also include vascular-wall cells that do not necessarily exhibit anatomical features of pericytes proper, for example, adventitial cells in muscular veins.…”

“…Our data are consistent with recent studies showing that in vivo, transplants of BM cells were able to form bone and support marrow formation, while white adipose-derived stromal cells (WAT), cells from umbilical cord (UC), and skin fibroblasts (SF) were not ( Kaltz et al., 2008 , Reinisch et al., 2015 ). Importantly, the “MSCs” derived from cord blood (CB) used in our study must be clearly distinguished from fibroblastic cells derived from UC “MSCs” in the Reinisch study; UC cells fail to differentiate in vitro and in vivo ( Kaltz et al., 2008 , Liedtke et al., 2016 , Reinisch et al., 2015 ), differ in their typical HOX expression pattern ( Liedtke et al., 2010 , Liedtke et al., 2016 ), and have a different molecular transcriptomic signature lacking relevant integrin-binding sialoprotein ( IBSP ) expression ( Bosch et al., 2012 ). Differences in our study include culture in 20% fetal bovine serum (FBS) and use of a ceramic carrier that favors direct osteogenesis (no evidence of endochondral bone formation).…”

High HOXD4 protein expression in gastric adenocarcinoma tissues indicates unfavorable clinical outcomes

“…The HOX (homeobox) gene, which is about 180-bps sequence, encodes a protein domain containing 60 amino acids called homeodomain. [19] The homeodomain combines with various specific DNA and thus regulates the different expression of downstream genes. Recently, increasing evidence shows that HOX gene may play a crucial role in regulating the progression of various tumor types.…”