Project description:Characterizing the stem cells responsible for lung repair and regeneration is important for the treatment of pulmonary diseases. Recently, a unique cell population located at the bronchioalveolar-duct junctions has been proposed to comprise endogenous stem cells for lung regeneration. However, the role of bronchioalveolar stem cells (BASCs) in vivo remains debated, and the contribution of such cells to lung regeneration is not known. Here we generated a genetic lineage-tracing system that uses dual recombinases (Cre and Dre) to specifically track BASCs in vivo. Fate-mapping and clonal analysis showed that BASCs became activated and responded distinctly to different lung injuries, and differentiated into multiple cell lineages including club cells, ciliated cells, and alveolar type 1 and type 2 cells for lung regeneration. This study provides in vivo genetic evidence that BASCs are bona fide lung epithelial stem cells with deployment of multipotency and self-renewal during lung repair and regeneration.
Project description:Liver dysfunction and cirrhosis affect vasculature in several organ systems and cause impairment of organ functions, thereby increasing morbidity and mortality. If a mouse model of hepatopulmonary syndrome (HPS) could be established, greater insight into the genetic basis of the disease would be gained. Our objectives were to establish a mouse model of lung injury after common bile duct ligation (CBDL) and to investigate pulmonary pathogenesis for application in future therapeutic approaches. Balb/c mice were subjected to CBDL. Immunohistochemical analyses and real-time quantitative reverse transcriptional polymerase chain reaction were performed on pulmonary tissues. The presence of HPS markers were detected by western blot and microarray analyses. We observed extensive proliferation of CD31-positive pulmonary vascular endothelial cells 2 weeks after CBDL, and identified 11 up-regulated and 8 down-regulated proteins that were associated with angiogenesis. MMP-9 protein was highly expressed at 3 weeks after CBDL, and less expressed in lungs of the control group. Contrary to our expectation, lung pathology in our mouse model exhibited differences from that of rat models, and the mechanisms responsible for these differences are unknown. This phenomenon may be explained by contrasting processes related to TNF induction of angiogenic signaling pathways in the inflammatory phase; thus, we suggest that our mouse model can be applied to pulmonary pathological analyses in the inflammatory phase, i.e., to systemic inflammatory response syndrome, acute lung injury, and MOD syndrome. After induction of anesthesia, a median abdominal incision was made and the common bile duct was identified. The duct was dissected carefully under a microscope, and doubly ligated with 7-0 Prolene and transected. In the sham operation (control) group, the duct was dissected without common bile duct ligation. Mice were sacrificed at 2 and 3 weeks after surgery. CD31-positive cells were assembled from three mice in each group.
Project description:To investigate the heterogeneity of lung CD140a+ mesenchymal cells (fibroblasts) and identify the specific lung fibroblast subset, we purified CD140a+ lung cells using CD140a-EGFP reporter mice for a higher-resolution scRNA-seq.
Project description:Bronchioalveolar stem cells (BASCs) are a potential source for lung regeneration, but direct in vivo evidence is critically missing since specific genetic labeling of BASCs has not been possible. We developed a novel cell tracing approach based on intein-mediated assembly of newly engineered split-effectors, allowing selective targeting of dual-marker expressing BASCs. We found that BASCs generate the majority of distal lung airway cells after bronchioalveolar damage but only moderately contribute to cellular turnover under homeostatic conditions. Importantly, DTA-mediated ablation of BASCs compromised proper regeneration of distal airways. The study defines BASCs as crucial components of the lung repair machinery and provides a paradigmatic example for the detection and manipulation of stem cells that cannot be recognized by a single marker alone.
Project description:Here, we used single cell RNA-sequencing (scRNA-seq) to profile 13-week post-conception distal human fetal lung explants cultured in an air liquid interface system and treated with an LGR5 ectodomain adenovirus that inhibits R-Spondin function or control adenovirus. A third, non-infected, condition was also sequenced. We also performed scRNA-seq on distal human fetal lung tissue from an 8.4-week post-conception biological specimen. Diverse cell lineages were captured in all data sets, and include epithelium, mesenchyme, immune, neurons, and endothelium.
Project description:To investigate the heterogeneity of lung stromal cells and identify the specific lung stromal subset, we performed single cell RNA-sequencing (scRNA-seq) on lung stromal cells (CD45-CD31-CD326-). Around 6800 cells were captured using the 10x Chromium technology.
Project description:Here, we performed single cell RNA sequencing (scRNA-seq) of 1 (one) human fetal lung tissue specimen (18.9 week) and 2 (two) human fetal intestine specimens (12.1 and 18.9 week) (total of 3 (three) independent biological specimens). The data set is composed of approximately 5,000 lung cells and 7,500 intestine cells. Lineages captured across both tissues include but are not limited to epithelium, stroma, immune, neurons and endothelium.
Project description:To investigate the CD140a+ mesenchymal cell heterogeneity in the lung in both steady and tumor-bearing conditions, we utilized CD140aEGFP reporter mice, and purified CD140a+ lung mesenchymal cells from naive and tumor-bearing mice and performed scRNA-seq.