Search

Organoid models have become an integral part of the research methodology in the lung field. These systems allow for the study of progenitor and stem cell self-renewal, self-organization, and differentiation. Distinct models of lung organoids mimicking various anatomical regions of mature lungs have emerged in parallel to the increased gain of knowledge regarding epithelial stem and progenitor cell populations and the corresponding mesenchymal cells that populate the in vivo niche. In the distal lung, type 2 alveolar epithelial cells (AEC2s) represent a stem cell population that is engaged in regenerative mechanisms in response to various insults. These cells self-renew and give rise to AEC1s that carry out gas exchange. Multiple experimental protocols allowing the generation of alveolar organoids, or alveolospheres, from murine lungs have been described. Among the drawbacks have been the requirement of transgenic mice allowing the isolation of AEC2s with high viability and purity, and the occasional emergence of bronchiolar and bronchioalveolar organoids. Here, we provide a refined gating strategy and an optimized protocol for the generation of alveolospheres from wild-type mice. Our approach not only overcomes the need for transgenic mice to generate such organoids, but also yields a pure culture of alveolospheres that is devoid of bronchiolar and bronchioalveolar organoids. Our protocol contributes to the standardization of this important research tool. [ABSTRACT FROM AUTHOR]

Bleomycin (BLM)-induced lung injury in mice is a valuable model for investigating the molecular mechanisms that drive inflammation and fibrosis and for evaluating potential therapeutic approaches to treat the disease. Given high variability in the BLM model, it is critical to accurately phenotype the animals in the course of an experiment. In the present study, we aimed to demonstrate the utility of microscopic computed tomography (µCT) imaging combined with an artificial intelligence (AI)-convolutional neural network (CNN)-powered lung segmentation for rapid phenotyping of BLM mice. µCT was performed in freely breathing C57BL/6J mice under isoflurane anesthesia on days 7 and 21 after BLM administration. Terminal invasive lung function measurement and histological assessment of the left lung collagen content were conducted as well. µCT image analysis demonstrated gradual and time-dependent development of lung injury as evident by alterations in the lung density, air-to-tissue volume ratio, and lung aeration in mice treated with BLM. The right and left lung were unequally affected. µCT-derived parameters such as lung density, air-to-tissue volume ratio, and nonaerated lung volume correlated well with the invasive lung function measurement and left lung collagen content. Our study demonstrates the utility of AI-CNN-powered µCT image analysis for rapid and accurate phenotyping of BLM mice in the course of disease development and progression. NEW & NOTEWORTHY: Microscopic computed tomography (µCT) imaging combined with an artificial intelligence (AI)-convolutional neural network (CNN)-powered lung segmentation is a rapid and powerful tool for noninvasive phenotyping of bleomycin mice over the course of the disease. This, in turn, allows earlier and more reliable identification of therapeutic effects of new drug candidates, ultimately leading to the reduction of unnecessary procedures in animals in pharmacological research. [ABSTRACT FROM AUTHOR]

This article explores the distribution and composition of the ferritin complex in the adult brain and its connection to neuroferritinopathy (NF), a type of neurodegeneration with brain iron accumulation (NBIA). NF is characterized by symptoms like movement disturbances and tremors. The study identifies a novel variant in the ferritin heavy chain gene (FTH1) that is associated with NF and provides insights into the role of ferritin in both healthy and diseased brains. [Extracted from the article]

Apolipoprotein A-I (apoA-I) mediates reverse cholesterol transport (RCT) out of cells. In addition to its important role in the RTC, apoA-I also possesses anti-inflammatory and antioxidative functions including the ability to activate inflammasome and signal via toll-like receptors. Dysfunctional apoA-I or its low abundance may cause accumulation of cholesterol mass in alveolar macrophages, leading to the formation of foam cells. Increased numbers of foam cells have been noted in the lungs of mice after experimental exposure to cigarette smoke, silica, or bleomycin and in the lungs of patients suffering from different types of lung fibrosis, including idiopathic pulmonary fibrosis (IPF). This suggests that dysregulation of lipid metabolism may be a common event in the pathogenesis of interstitial lung diseases. Recognition of the emerging role of cholesterol in the regulation of lung inflammation and remodeling provides a challenging concept for understanding lung diseases and offers novel and exciting avenues for therapeutic development. Accordingly, a number of preclinical studies demonstrated decreased expression of inflammatory and profibrotic mediators and preserved lung tissue structure following the administration of the apoA-I or its mimetic peptides. This review highlights the role of apoA-I in lung fibrosis and provides evidence for its potential use in the treatment of this pathological condition. [ABSTRACT FROM AUTHOR]

Repair-supportive mesenchymal cells (RSMCs) have been recently reported in the context of naphthalene (NA)-induced airway injury and regeneration. These cells transiently express smooth muscle actin (Acta2) and are enriched with platelet-derived growth factor receptor alpha (Pdgfra) and fibroblast growth factor 10 (Fgf10) expression. Genetic deletion of Ctnnb1 (gene coding for beta catenin) or Fgf10 in these cells using the Acta2-Cre-ERT2 driver line after injury (defined as NA-Tam condition; Tam refers to tamoxifen) led to impaired repair of the airway epithelium. In this study, we demonstrate that RSMCs are mostly captured using the Acta2-Cre-ERT2 driver when labeling occurs after (NA-Tam condition) rather than before injury (Tam-NA condition), and that their expansion occurs mostly between days 3 and 7 following NA treatment. Previous studies have shown that lineage-traced peribronchial GLI1+ cells are transiently amplified after NA injury. Here, we report that Gli1 expression is enriched in RSMCs. Using lineage tracing with Gli1Cre−ERT2 mice combined with genetic inactivation of Fgf10, we show that GLI1+ cells with Fgf10 deletion fail to amplify around the injured airways, thus resulting in impaired airway epithelial repair. Interestingly, Fgf10 expression is not upregulated in GLI1+ cells following NA treatment, suggesting that epithelial repair is mostly due to the increased number of Fgf10-expressing GLI1+ cells. Co-culture of SCGB1A1+ cells with GLI1+ cells isolated from non-injured or injured lungs showed that GLI1+ cells from these two conditions are similarly capable of supporting bronchiolar organoid (or bronchiolosphere) formation. Single-cell RNA sequencing on sorted lineage-labeled cells showed that the RSMC signature resembles that of alveolar fibroblasts. Altogether, our study provides strong evidence for the involvement of mesenchymal progenitors in airway epithelial regeneration and highlights the critical role played by Fgf10-expressing GLI1+ cells in this context. [ABSTRACT FROM AUTHOR]

Insulin-like growth factor (IGF) signaling controls the development and growth of many organs, including the lung. Loss of function of Igf1 or its receptor Igf1r impairs lung development and leads to neonatal respiratory distress in mice. Although many components of the IGF signaling pathway have shown to be dysregulated in idiopathic pulmonary fibrosis (IPF), the expression pattern of such components in different cellular compartments of the developing and/or fibrotic lung has been elusive. In this study, we provide a comprehensive transcriptional profile for such signaling components during embryonic lung development in mice, bleomycin-induced pulmonary fibrosis in mice and in human IPF lung explants. During late gestation, we found that Igf1 is upregulated in parallel to Igf1r downregulation in the lung mesenchyme. Lung tissues derived from bleomycin-treated mice and explanted IPF lungs revealed upregulation of IGF1 in parallel to downregulation of IGF1R, in addition to upregulation of several IGF binding proteins (IGFBPs) in lung fibrosis. Finally, treatment of IPF lung fibroblasts with recombinant IGF1 led to myogenic differentiation. Our data serve as a resource for the transcriptional profile of IGF signaling components and warrant further research on the involvement of this pathway in both lung development and pulmonary disease. [ABSTRACT FROM AUTHOR]

The number of adult myofibers in Drosophila is determined by the number of founder myoblasts selected from a myoblast pool, a process governed by fibroblast growth factor (FGF) signaling. Here, we show that loss of cabeza (caz) function results in a reduced number of adult founder myoblasts, leading to a reduced number and misorientation of adult dorsal abdominal muscles. Genetic experiments revealed that loss of caz function in both adult myoblasts and neurons contributes to caz mutant muscle phenotypes. Selective overexpression of the FGF receptor Htl or the FGF receptor-specific signaling molecule Stumps in adult myoblasts partially rescued caz mutant muscle phenotypes, and Stumps levels were reduced in caz mutant founder myoblasts, indicating FGF pathway deregulation. In both adult myoblasts and neurons, caz mutant muscle phenotypes were mediated by increased expression levels of Xrp1, a DNA-binding protein involved in gene expression regulation. Xrp1-induced phenotypes were dependent on the DNA-binding capacity of its AT-hook motif, and increased Xrp1 levels in founder myoblasts reduced Stumps expression. Thus, control of Xrp1 expression by Caz is required for regulation of Stumps expression in founder myoblasts, resulting in correct founder myoblast selection. Author summary: Skeletal muscles mediate movement, and therefore, proper structure and function of skeletal muscles is required for respiration, locomotion, and posture. Adult muscles arise from fusion of muscle precursor cells during development. In the fruit fly Drosophila melanogaster, muscle precursor cells come in two flavors: founder cells and fusion-competent cells. The number of founder cells selected during development corresponds to the number of adult muscles formed. Here, we report that inactivation of the Drosophila caz gene results in muscle developmental defects. Loss of caz function in both muscle precursor cells and the nerve cells that innervate muscles contributes to the muscle developmental defect. At the molecular level, loss of caz function leads to increased levels of Xrp1. Xrp1 regulates the expression of many other genes, including genes that produce components of the FGF signaling pathway, which is known to be involved in founder cell selection. In all, we uncovered a novel molecular mechanism that regulates founder cell selection during muscle development. [ABSTRACT FROM AUTHOR]

Central nervous system myelin is a multilayered membrane produced by oligodendrocytes to increase neural processing speed and efficiency, but the molecular mechanisms underlying axonal selection and myelin wrapping are unknown. Here, using combined morphological and molecular analyses in mice and zebrafish, we show that adhesion molecules of the paranodal and the internodal segment work synergistically using overlapping functions to regulate axonal interaction and myelin wrapping. In the absence of these adhesive systems, axonal recognition by myelin is impaired with myelin growing on top of previously myelinated fibers, around neuronal cell bodies and above nodes of Ranvier. In addition, myelin wrapping is disturbed with the leading edge moving away from the axon and in between previously formed layers. These data show how two adhesive systems function together to guide axonal ensheathment and myelin wrapping, and provide a mechanistic understanding of how the spatial organization of myelin is achieved. It remains unclear how myelin is targeted specifically to axons while sparing neuronal cell bodies and dendrites, or how small gaps, the nodes of Ranvier, are left unmyelinated along the axon. In this study, authors used genetic analyses in zebrafish and mice to demonstrate that molecules of the paranodal axo-glial junction act jointly with molecules of the internodal domain to regulate axonal interactions and myelin wrapping, and that in the combined absence of these molecules myelin sheaths are misplaced. [ABSTRACT FROM AUTHOR]

Energy consumption in the building sector is responsible for a very large amount of electricity consumption worldwide. The reduction of this consumption is a crucial issue in order to achieve sustainability. The objective of this work is to investigate the use of phase change materials (PCMs) in the building walls in order to reduce the heating and the cooling loads. The novelty of this work is based on the investigation of different scenarios about the position of the PCM layer in the south and the north walls. PCMs can improve the thermal performance and the thermal comfort of a building due to their ability to store large amounts of thermal energy in latent form and so to reduce the temperature fluctuations of the structural components, keeping them within the desired temperature levels. More specifically, this work presents and compares the heating loads, the cooling loads and the temperature distribution of a building in Athens (Greece), with and without PCMs in different positions in the south wall and in the north walls. The simulation is performed with the commercial software TRNSYS 17, using the TRNSYS component: type 1270 (PCM Wall). The results proved that the maximum energy savings per year were achieved by the combination of the insulation and the PCM layer in the north and south walls. More specifically, the reductions in the heating and the cooling loads were found to be 1.54% and 5.90%, respectively. Furthermore, the temperature distribution with the use of a PCM layer is the most acceptable, especially during the summer period. [ABSTRACT FROM AUTHOR]