Project description:The pulmonary alveolar epithelium mainly composed of two types of epithelial cells: alveolar type I (AT1) and type II (AT2) cells. AT2 cells are the alveolar stem cells, and can differentiate into AT1 cells post-pneumonectomy (PNX). Here, we found that, compared with control mice (Sftpc-CreER; Cdc42flox/+; Rosa26-mTmG) at post-PNX day 21, Cdc42 AT2 null mice (Sftpc-CreER; Cdc42flox/-; Rosa26-mTmG) at post-PNX day 21 undergone fibrotic change. By using 10X genomics “Chromium Single Cell” technology, we performed single-cell RNA-seq analyses of AT2 cells of sham treated control mice (C0), AT2 cells of control mice at post PNX day 21 (C21) , AT2 cells of sham treated Cdc42 AT2 null mice (N0), and AT2 cells of Cdc42 AT2 null mice at post PNX day 21 (N21). The study identified a specific gene signature in AT2 cells of Cdc42 AT2 null mice at post PNX day 21 which is related to the fibrosis phenotype of Cdc42 AT2 null mice.
Project description:AT2 cells are the resident progenitor cells in alveoli, capable of self-proliferation and differentiation into alveolar type I cells during homeostatic maintenance and tissue regeneration. The AT2 cell population is heterogenous. We identified a small subpopulation of AT2 cells that express high levels of CD44 (CD44hi) and display progenitor functions during alveoli homeostasis. To further analyze the heterogeneity of the AT2 cell population and characterize CD44hi AT2 cells, we performed single cell RNA-seq on the total AT2 cell population and CD44hi AT2 cells.
Project description:The pulmonary alveolar epithelium which play key role in lung biological function is mainly composed of two types of epithelial cells: alveolar type I (AT1) and type II (AT2) cells. We know very little about developmental heterogeneity of the AT1 cell population. By using 10X genomics “Chromium Single Cell” technology, we performed single-cell RNA-seq (scRNA-seq) analyses of AT1 cells at postnatal day 3 (P3), P15, and P60, along with AT2 cells (P60) in mice. Our study identified a robust new genetic marker (Igfbp2) of postnatal AT1 cells. The study also provided the transcriptome information of AT1 cells during alveologensis.
Project description:Lung aging triggers the onset of various chronic lung diseases, with alveolar repair being a key focus for alleviating pulmonary conditions. The regeneration of epithelial structures, particularly the differentiation from type II alveolar epithelial (AT2) cells to type I alveolar epithelial (AT1) cells, serves as a prominent indicator of alveolar repair. Nonetheless, the precise role of aging in impeding alveolar regeneration and the underlying mechanism remain to be fully elucidated. To elucidate the mechanisms underlying AT2 cell functional decline during lung aging, we employed transcriptomic techniques to explicit the differences in gene expression between AT2 cells of young (3-month old) and old (24-month old) mouse lungs, and revealed correlation between inflammatory factors and genes regulating proliferation and differentiation. Physiological aging-induced chronic inflammation impairs AT2 cell functions, hindering tissue repair and promoting lung disease progression. This study offers novel insights into chronic inflammation's impact on stem cell-mediated alveolar regeneration.
Project description:Idiopathic pulmonary fibrosis (IPF) is a lethal progressive lung disease urgently needing new therapies. Current treatments only delay disease progression, leaving lung transplant as the sole remaining option. Recent studies support a model whereby IPF arises because alveolar epithelial type II (AT2) cells, which normally mediate distal lung regeneration, acquire airway and/or mesenchymal characteristics, preventing proper repair. Mechanisms driving this abnormal differentiation remain unclear. We performed integrated transcriptomic and epigenomic analysis of purified AT2 cells which revealed genome-wide alterations in IPF lungs. The most prominent epigenetic alteration was activation of an enhancer in thyroid receptor interactor 13 (TRIP13), coinciding with TRIP13 upregulation. TRIP13 is broadly implicated in epithelial-mesenchymal plasticity and transforming growth factor-beta signaling. In cultured human AT2 cells and lung slices, small molecule TRIP inhibitor DCZ0415 prevented acquisition of the mesenchymal gene signature characteristic of IPF, suggesting TRIP13 inhibition as a potential therapeutic approach to fibrotic disease.
Project description:Background: Lung function is dependent upon the precise regulation of the synthesis, storage, and catabolism of tissue and alveolar lipids. Results: Activation of SREBP (Sterol Response Element Binding Protein) induced lipogenesis in alveolar epithelial cells, causing neutral lipid accumulation, lung inflammation, and tissue remodeling. Conclusions: The accumulation of neutral lipids in type II epithelial cells and alveolar macrophages caused lung inflammation, consistent with findings in lipid storage disorders. Significance: Pulmonary lipotoxicity may contribute to the pathogenesis of lung dysfunction associated with diabetes, obesity, and other metabolic disorders. Genome-wide transcription profiling comparison between doxycycline-exposed SFTPC-rtTAWT/Tg/(tetO)7CMV-CreWT/Tg/Insig1flox/flox/Insig2-/- mice (i.e., Insig1/2∆/∆ ) and Insig1flox/flox/Insig2-/- . Three independent pooled RNA from isolated lung type 2 cells of each genotype were used.
Project description:Background: Lung function is dependent upon the precise regulation of the synthesis, storage, and catabolism of tissue and alveolar lipids. Results: Activation of SREBP (Sterol Response Element Binding Protein) induced lipogenesis in alveolar epithelial cells, causing neutral lipid accumulation, lung inflammation, and tissue remodeling. Conclusions: The accumulation of neutral lipids in type II epithelial cells and alveolar macrophages caused lung inflammation, consistent with findings in lipid storage disorders. Significance: Pulmonary lipotoxicity may contribute to the pathogenesis of lung dysfunction associated with diabetes, obesity, and other metabolic disorders.
Project description:These studies profiled the expression of mRNA in lung type II alveolar epithelial cells during lipopolysacchride induced lung injury in the presence or absence of Foxp3+ Regulatory T Cells Baseline, uninjured lung type II alveolar epithelial (AT2) cells or resolving AT2 cells, in the presence or absence of Foxp3+ regulatory T cells (Tregs), were sorted (7 days after intratracheal instillation of LPS for resolving conditions) and mRNAs differentially expressed (DE) between control AT2 cells, resolving AT2 cells with Tregs present, or resolving AT2 cells in mice depleted of Tregs were identified using microarrays.
Project description:Alveolar type 2 (AT2) cells function as stem cells in the adult lung and aid in injury-repair. The current study aimed to understand the signaling events that control differentiation of this therapeutically relevant cell type during human development through differentiation of lung progenitor organoids to AT2 cells and benchmarking against primary AT2 organoids.