Mesenchymal Stromal Cells from Neonatal Tracheal Aspirates Demonstrate a Pattern of Lung-Specific Gene Expression

Abstract

We have previously isolated mesenchymal stromal cells (MSCs) from the tracheal aspirates of premature neonates with respiratory distress. Although isolation of MSCs correlates with the development of bronchopulmonary dysplasia, the physiologic role of these cells remains unclear. To address this, we further characterized the cells, focusing on the issues of gene expression, origin, and cytokine expression. Microarray comparison of early passage neonatal lung MSC gene expression to cord blood MSCs and human fetal and neonatal lung fibroblast lines demonstrated that the neonatal lung MSCs differentially expressed 971 gene probes compared with cord blood MSCs, including the transcription factors Tbx2, Tbx3, Wnt5a, FoxF1, and Gli2, each of which has been associated with lung development. Compared with lung fibroblasts, 710 gene probe transcripts were differentially expressed by the lung MSCs, including IL-6 and IL-8/CXCL8. Differential chemokine expression was confirmed by protein analysis. Further, neonatal lung MSCs exhibited a pattern of Hox gene expression distinct from cord blood MSCs but similar to human fetal lung fibroblasts, consistent with a lung origin. On the other hand, limiting dilution analysis showed that fetal lung fibroblasts form colonies at a significantly lower rate than MSCs, and fibroblasts failed to undergo differentiation along adipogenic, osteogenic, and chondrogenic lineages. In conclusion, MSCs isolated from neonatal tracheal aspirates demonstrate a pattern of lung-specific gene expression, are distinct from lung fibroblasts, and secrete pro-inflammatory cytokines.

Stem cell–based therapies for the newborn lung and brain: Possibilities and challenges

“…For example, some reports have linked BPD risk with decreased endothelial progenitors in the circulation as assessed through clonogenic analysis of late outgrowth endothelial colony-forming cells (ECFCs) 8, 9 . In addition, lung resident mesenchymal stem cells (MSCs) isolated from the tracheal aspirates of preterm neonates display an altered, proinflammatory phenotype 10, 11 suggesting that both depletion and dysfunction of endogenous progenitor stem cells may predispose to the development of BPD.…”

Small noncoding differentially methylated copy-number variants, including lncRNA genes, cause a lethal lung developmental disorder

“…FOXF1 and its mouse ortholog are predominantly expressed in subepithelial mesenchymal tissues of developing lung and foregut (Chang and Ho 2001;Mahlapuu et al 2001a;Maeda et al 2007;Bozyk et al 2011). Homozygous mice deficient for Foxf1 die in utero by embryonic day 10 (E10) due to defects in mesodermal differentiation and cell adhesion (Mahlapuu et al 2001b).…”

Stem Cells for the Prevention of Neonatal Lung Disease

“…Evidence of stem cell perturbation has also been reported in the preterm infant population in tracheal aspirates [20,21] and umbilical cord blood (UCB) samples [22,23,24]. The presence of MSCs in tracheal aspirates of preterm infants has been reported as an indicator of increased risk of the development of BPD [20] and these tracheal MSCs were shown to display a pattern of lung-specific gene expression and secrete proinflammatory cytokines [21]. In UCB from preterm infants, ECFCs were reported to have altered characteristics, including increased susceptibility to in vitro hyperoxia exposure compared to that of term newborns [23].…”

“…Likewise, the function of resident human and rat lung ECFCs display decreased self-renewal and in vitro vascular network-forming capacity [19]. Evidence of stem cell perturbation has also been reported in the preterm infant population in tracheal aspirates [20,21] and umbilical cord blood (UCB) samples [22,23,24]. The presence of MSCs in tracheal aspirates of preterm infants has been reported as an indicator of increased risk of the development of BPD [20] and these tracheal MSCs were shown to display a pattern of lung-specific gene expression and secrete proinflammatory cytokines [21].…”