Biology subjects

Rabata, A.

Publications and source records attributed to Rabata, A..

4 recordsLinked to original sources

bioRxiv2026

Immortalized AT2 Cell Lines from Healthy and IPF Lungs Enable 2D and 3D Cultures

Idiopathic pulmonary fibrosis (IPF) is characterized by impaired alveolar type 2 cell regeneration. However, robust in vitro models of human distal lung epithelium are limited. In this study, we generated immortalized AT2 cell lines from healthy and IPF lungs using HTII-280 sorting and SV40 large T antigen transduction. These lines retain key features of alveolar epithelial biology in both 2D and 3D cultures, including self-renewal, differentiation, and transitional cell states. They form 3D organoids efficiently under optimized feeder-free, serum-free medium conditions, with higher colony-forming capacity in healthy AT2 cell lines comparing with IPF AT2 cell lines. These accessible models recapitulate alveolar epithelial biology, offering a platform for cell-biology research and therapeutic development in lung diseases.

cell biology↗

bioRxiv2025

Phosphatidylcholine Metabolism Controls Alveolar Progenitor Renewal and Pulmonary Fibrosis

Idiopathic pulmonary fibrosis (IPF) is a progressive, fatal lung disease marked by alveolar type 2 (AT2) stem cell dysfunction and excessive matrix deposition, with no effective treatments. Recent advances have recognized that AT2 cells act as stem cells, in addition to their role in the production of pulmonary surfactants in the distal alveolar space. We and others have reported a failure of AT2 regeneration and a loss of AT2 cells in IPF. We recently further reported that there is a defect in lipid metabolism in IPF AT2 cells and we discovered a selective loss of lysophosphatidylcholine acyltransferase 1 (LPCAT1) in AT2 cells from IPF, as well as in AT2 cells from bleomycin-injured mice. Pharmacological and genetic experiments confirm that LPCAT1 is required for AT2 cell renewal in 3D organoid assays. AT2 cell-specific Lpcat1 deletion resulted in reduced AT2 renewal, spontaneous lung fibrosis, and heightened susceptibility to bleomycin-induced fibrosis in mice in vivo. Expression-based high-content drug screening with an LPCAT1 knock-in cell line identified several drug families that upregulated LPCAT1 expression. We further confirmed that anti-malarial artesunate and PLA2 inhibitor ONO-RS-082 increased LPCAT1 mRNA expression, promoted AT2 renewal, and attenuated bleomycin-induced lung fibrosis in mice in vivo. Our findings establish LPCAT1 as a critical regulator of AT2 renewal and lipid metabolism in IPF, suggesting that reactivation of LPCAT1 could offer a novel therapeutic strategy for restoring alveolar progenitor function and mitigating lung fibrosis.

cell biology↗

bioRxiv2025

Activation of the impaired NAMPT/SIRT7/SOD2 axis restores alveolar progenitor cell homeostasis in idiopathic pulmonary fibrosis and reverses pulmonary fibrosis in mice

Alveolar type II (AT2) progenitor cell exhaustion and impaired regenerative capacity are key pathogenic hallmarks in idiopathic pulmonary fibrosis (IPF). Nicotinamide adenine dinucleotide (NAD+) functions as a central regulator of cellular energy metabolism. We have reported that downregulation of NAD+-dependent sirtuin signaling contributes to the impaired progenitor function of IPF AT2s. In this study, we identified that a key NAD+ biosynthesis enzyme, nicotinamide phosphoribosyltransferase (NAMPT), is significantly downregulated in IPF AT2s. NAMPT deficiency impairs AT2 renewal and enhances lung fibrosis through downregulation of SIRT7 and SOD2, which results in increased oxidative stress, mitochondrial dysfunction, induction of pathological transitional gene expression and impaired regenerative capacity to generate alveolar type I (AT1) cell required for gas exchange. Mice with deletion of Nampt in AT2s showed severely impaired AT2 renewal and increased susceptibility to bleomycin lung injury and spontaneous fibrois. Activation of NAMPT by small molecule activators promoted AT2 renewal, restored homeostasis, and reversed lung fibrosis. NAMPT activation could be a therapeutic strategy for restoring AT2 progenitor function and halting or reversing progressive pulmonary fibrosis.

cell biology↗

bioRxiv2020

3D cell culture models demonstrate a role for FGF and WNT signaling in regulation of lung epithelial cell fate and morphogenesis

FGF signaling plays an essential role in lung development, homeostasis, and regeneration. Several FGF ligands were detected in the developing lungs, however, their roles have not been fully elucidated. We employed mouse 3D cell culture models and imaging to ex vivo study of a) the role of FGF ligands in lung epithelial morphogenesis and b) the interplay of FGF signaling with epithelial growth factor (EGF) and WNT signaling pathways. In non-adherent conditions, FGF signaling promoted formation of lungospheres from lung epithelial stem/progenitor cells (LSPCs). Based on their architecture, we defined three distinct phenotypes of lungospheres. Ultrastructural and immunohistochemical analyses showed that LSPCs produced more differentiated lung cell progeny. In 3D extracellular matrix, FGF2, FGF7, FGF9, and FGF10 promoted lung organoid formation with similar efficiency. However, FGF9 showed reduced capacity to promote lung organoid formation, suggesting that FGF9 has a reduced ability to sustain LSPCs survival and/or initial divisions. Analysis of lung organoid phenotypes revealed that FGF7 and FGF10 produce bigger organoids and induce organoid branching with higher frequency than FGF2 and FGF9. Higher FGF concentration and/or the use of FGF2 with increased stability and affinity to FGF receptors both increased lung organoid and lungosphere formation efficiency, respectively, suggesting that the level of FGF signaling is a crucial driver of LSPC survival and differentiation, and also lung epithelial morphogenesis. EGF signaling played a supportive but nonessential role in FGF-induced lung organoid formation. Moreover, analysis of tissue architecture and cell type composition confirmed that the lung organoids contained alveolar-like regions with cells expressing alveolar type I and type II cell markers, as well as airway-like structures with club cells and ciliated cells. WNT signaling enhanced the efficiency of lung organoid formation, but in the absence of FGF10 signaling, the organoids displayed limited branching and less differentiated phenotype. In summary, we present lung 3D cell culture models as useful tools to study the role and interplay of signaling pathways in lung development and we reveal roles for FGF ligands in regulation of mouse lung morphogenesis ex vivo.

developmental biology↗