During late lung development, alveolar and microvascular development is finalized to enable sufficient gas exchange. Impaired late lung development manifests as bronchopulmonary dysplasia (BPD) in preterm infants. Single-cell RNA sequencing (scRNA-seq) allows for assessment of complex cellular dynamics during biological processes, such as development. Here, we use MULTI-seq to generate scRNA-seq profiles of over 66,000 cells from 36 mice during normal or impaired lung development secondary to hyperoxia with validation of some of the findings in lungs from BPD patients. We observe dynamic populations of cells, including several rare cell types and putative progenitors. Hyperoxia exposure, which mimics the BPD phenotype, alters the composition of all cellular compartments, particularly alveolar epithelium, stromal fibroblasts, capillary endothelium and macrophage populations. Pathway analysis and predicted dynamic cellular crosstalk suggest inflammatory signaling as the main driver of hyperoxia-induced changes. Our data provides a single-cell view of cellular changes associated with late lung development in health and disease.
ShcA is an important mediator of ErbB2-and transforming growth factor  (TGF-)-induced breast cancer cell migration, invasion, and metastasis. We show that in the context of reduced ShcA levels, the bone morphogenetic protein (BMP) antagonist chordin-like 1 (Chrdl1) is upregulated in numerous breast cancer cells following TGF- stimulation. BMPs have emerged as important modulators of breast cancer aggressiveness, and we have investigated the ability of Chrdl1 to block BMP-induced increases in breast cancer cell migration and invasion. Breast cancer-derived conditioned medium containing elevated concentrations of endogenous Chrdl1, as well as medium containing recombinant Chrdl1, suppresses BMP4-induced signaling in multiple breast cancer cell lines. Live-cell migration assays reveal that BMP4 induces breast cancer migration, which is effectively blocked by Chrdl1. We demonstrate that BMP4 also stimulated breast cancer cell invasion and matrix degradation, in part, through enhanced metalloproteinase 2 (MMP2) and MMP9 activity that is antagonized by Chrdl1. Finally, high Chrdl1 expression was associated with better clinical outcomes in patients with breast cancer. Together, our data reveal that Chrdl1 acts as a negative regulator of malignant breast cancer phenotypes through inhibition of BMP signaling. Breast cancer is a heterogeneous disease that can be subdivided into distinct molecular subtypes through the integration of gene expression and genomics data (1, 2). While ErbB2 ϩ breast cancers are considered a poor-prognosis subtype (3), other signaling pathways can further modulate their malignant phenotypes. The transforming growth factor  (TGF-) family is a prominent example that has been shown to enhance the migratory, invasive, and metastatic abilities of ErbB2 ϩ breast cancer cells (4-7). We have previously demonstrated that the ShcA adaptor protein plays an important role, downstream of TGF- and ErbB2 signaling pathways, in mediating these cellular responses (8, 9). Loss of ShcA expression in ErbB2-expressing cells significantly reduced tumor growth, which was the result of reduced proliferation, diminished endothelial cell recruitment, and elevated apoptosis (9). In the present study, through the use of microarray based transcriptional profiling, we identified elevated levels of chordin-like 1 (Chrdl1) in ErbB2 ϩ breast cancer cells following TGF- stimulation; however, this upregulation of Chrdl1 occurs only in the context of diminished ShcA levels.Bone morphogenetic proteins (BMPs) are secreted cytokines that belong to the TGF- family of proteins, and their aberrant expression is observed in numerous cancers, including breast cancer (10). However, much like the TGF- isoforms, there are conflicting reports on whether BMPs exert pro-or antitumorigenic effects on cancer cells (11,12). In breast cancer, BMP4 has been shown to promote cancer cell migration and invasion (13-16). Similarly, BMP7 induces breast cancer cell proliferation, migration/invasion, and metastasis (17, 18). Interestingly, BMP4 an...
Sepsis is the main cause of morbidity and mortality in neonates. Mesenchymal stromal cells (MSCs) are potent immune-modulatory cells. Their effect in neonatal sepsis has never been explored. We hypothesized that human umbilical cord-derived MSCs (hUC-MSCs) improve survival in experimental neonatal sepsis. Sepsis was induced in 3-day-old rats by intravenous injection of Escherichia coli (5 × 10/rat). One hour after infection, rats were treated intravenously with normal saline, hUC-MSCs, or with interferon-γ preconditioned hUC-MSCs (10 cells/kg). Eighteen hours after infection, survival, bacterial counts, lung neutrophil and macrophage influx, phagocytosis and apoptosis of splenocytes plasma, and LL-37 concentration were evaluated. Animals were observed for survival for 72 h after E. coli injection. Treatment with either hUC-MSCs or preconditioned hUC-MSCs significantly increased survival (hUC-MSCs, 81%; preconditioned hUC-MSCs, 89%; saline, 51%; P < 0.05). Both hUC-MSCs and preconditioned hUC-MSCs enhanced bacterial clearance. Lung neutrophil influx was decreased with preconditioned hUC-MSCs. The number of activated macrophages (CD206) in the spleen was increased with hUC-MSCs and preconditioned hUC-MSCs; preconditioned hUC-MSCs increased the phagocytic activity of CD206 macrophages. hUC-MSCs and preconditioned hUC-MSCs decreased splenocyte apoptosis in E. coli infected rats. Finally, LL-37 plasma levels were elevated in neonatal rats treated with hUC-MSCs or preconditioned hUC-MSCs. hUC-MSCs enhance survival and bacterial clearance in experimental neonatal sepsis. hUC-MSCs may be an effective adjunct therapy to reduce neonatal sepsis-related morbidity and mortality.
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