Journal of respiratory biology and translational medicine最新文献

Idiopathic pulmonary fibrosis (IPF) is a progressive, irreversible, and fatal disease with an increasing incidence and limited therapeutic options. It is characterized by the formation and deposition of excess extracellular matrix proteins resulting in the gradual replacement of normal lung architecture by fibrous tissue. The cellular and molecular mechanism of IPF has not been fully understood. A hallmark in IPF is pulmonary fibroblast to myofibroblast transformation (FMT). During excessive lung repair upon exposure to harmful stimuli, lung fibroblasts transform into myofibroblasts under stimulation of cytokines, chemokines, and vesicles from various cells. These mediators interact with lung fibroblasts, initiating multiple signaling cascades, such as TGFβ1, MAPK, Wnt/β-catenin, NF-κB, AMPK, endoplasmic reticulum stress, and autophagy, contributing to lung FMT. Furthermore, single-cell transcriptomic analysis has revealed significant heterogeneity among lung myofibroblasts, which arise from various cell types and are adapted to the altered microenvironment during pathological lung repair. This review provides an overview of recent research on the origins of lung myofibroblasts and the molecular pathways driving their formation, with a focus on the interactions between lung fibroblasts and epithelial cells, endothelial cells, and macrophages in the context of lung fibrosis. Based on these molecular insights, targeting the lung FMT could offer promising avenues for the treatment of IPF.

Fibrosis is a progressive pathological process that severely impairs normal organ function. Current treatments for fibrosis are extremely limited, with no curative approaches available. In a recent article published in Cell, Zhang and colleagues employed drug screening using ACTA2 reporter iPSC-derived cardiac fibroblasts and identified artesunate as a potent antifibrotic drug by targeting MD2/TLR4 signaling. This study provides new insights into strategies for exploiting existing drugs to treat fibrosis.

Chronic obstructive pulmonary disease (COPD) and lung cancer are closely linked, with individuals suffering from COPD at a significantly higher risk of developing lung cancer. The mechanisms driving this increased risk are multifaceted, involving genomic instability, immune dysregulation, and alterations in the lung environment. Neutrophils, the most abundant myeloid cells in human blood, have emerged as critical regulators of inflammation in both COPD and lung cancer. Despite their short lifespan, neutrophils contribute to disease progression through various forms of programmed cell death, including apoptosis, necroptosis, ferroptosis, pyroptosis, and NETosis, a form of neutrophil death with neutrophil extracellular traps (NETs) formation. These distinct death pathways affect inflammatory responses, tissue remodeling, and disease progression in COPD and lung cancer. This review provides an in-depth exploration of the mechanisms regulating neutrophil death, the interplay between various cell death pathways, and their influence on disease progression. Additionally, we highlight emerging therapeutic approaches aimed at targeting neutrophil death pathways, presenting promising new interventions to enhance treatment outcomes in COPD and lung cancer.

Pulmonary arterial hypertension (PAH) is a progressive, lethal, and incurable disease of the pulmonary vasculature. A previous genome-wide association study (GWAS) with Affymetrix microarray analysis data exhibited elevated histidine triad nucleotide-binding protein 3 (HINT3) in the lung samples of PAH compared to control subjects (failed donors, FD) and the positive correlations of HINT3 with deubiquitinase USP11 and B-cell lymphoma 2 (BCL2). In this study, we aim to investigate the roles and interplay of USP11 and HINT3 in the apoptosis resistance of PAH. The levels of USP11 and HINT3 were increased in the lungs of idiopathic PAH (IPAH) patients and Hypoxia/Sugen-treated mice. USP11 and HINT3 interacted physically, as shown by co-immunoprecipitation (co-IP) assay in human pulmonary arterial endothelial cells (HPAECs). HINT3 was degraded by polyubiquitination, which was reversed by USP11. Furthermore, HINT3 interacted with the anti-apoptotic mediator, BCL2. Overexpression of USP11 increased BCL2 content, congruent to elevated lung tissue levels seen in IPAH patients and Hypoxia/Sugen-treated mice. Conversely, the knockdown of HINT3 function led to a depletion of BCL2. Thus, we conclude that USP11 stabilizes HINT3 activation, which contributes to endothelial apoptosis-resistance of pulmonary arterial endothelial cells in PAH. This can potentially be a novel therapeutic target for ubiquitination modulators for PAH.

Congenital Diaphragmatic Hernia (CDH) is a rare neonatal disorder causing diaphragmatic defects and cardiopulmonary hypoplasia, traditionally attributed to mechanical compression from organ herniation. However, emerging evidence suggests genetic mutations may independently impair lung development, prompting debate over CDH etiology. Here, we investigated the requirement of mitochondrial function guarded by LON peptidase 1 (Lonp1), a CDH risk gene, in either diaphragm or lung development. Lonp1 loss in skeletal muscles of the diaphragm led to its thinning and membranization, recapitulating the pathology of sac-type CDH. On the other hand, lung-specific inactivation caused severe hypoplasia with defective branching morphogenesis, independent of diaphragm anomalies. Molecularly, Lonp1 disruption dysregulated key transcription factors and signaling pathways known to be critical for early lung development. Our findings here revealed that mitochondrial defects contribute to the pathogenesis of CDH in an organ and cell type specific manner, opening new avenues for drug and therapeutic development.

The alveolar units, composed of alveolar epithelial type II cells (AT2) and type I cells (AT1), are essential for efficient gas exchange. While AT2 cells are known to play critical roles in alveolar homeostasis and regeneration, the contribution of heterogeneous AT2 cells to lung repair remains poorly understood. Here, we identified a distinct AT2 subpopulation that exclusively expressed Lysozyme 1 (Lyz1) through single-cell RNA sequencing (scRNA-seq) analyses. Cell fate mapping revealed that the Lyz1 ^CreERT2 mouse strain specifically labeled Lyz1-expressing AT2 cells in vivo at homeostasis. Following lung injury, Lyz1 ⁺ AT2 cells expanded and contributed to alveolar regeneration by generating both self-renewing AT2 cells and differentiating AT1 cells. We further observed the emergence of de novo Lyz1-expressing cells in the airways after lung injury. Additionally, Lyz1 ⁺ AT2 cells displayed significantly enhanced proliferative capacity compared with general bulk AT2 cells in 3D organoid cultures. These findings define Lyz1 ⁺ AT2 cells as a previously unrecognized progenitor population, expanding the paradigm of alveolar regeneration and providing insight into how epithelial diversity supports lung regeneration.

Spatial transcriptomics technologies have emerged as powerful tools for understanding cellular identity and function within the natural spatial context of tissues. Traditional transcriptomics techniques, such as bulk and single-cell RNA sequencing, lose this spatial information, which is critical for addressing many biological questions. Here, we present a protocol for high-resolution spatial transcriptomics using fixed frozen mouse lung sections mounted on 10X Genomics Xenium slides. This method integrates multiplexed fluorescent in situ hybridization (FISH) with high-throughput imaging to reveal the spatial distribution of mRNA molecules in lung tissue sections, allowing detailed analysis of gene expression changes in a mouse model of pulmonary hypertension (PH). We compared two tissue preparation methods, fixed frozen and fresh frozen, for compatibility with the Xenium platform. Our fixed frozen approach, utilizing a free-floating technique to mount thin lung sections onto Xenium slides at room temperature, preserved tissue integrity and maximized the imaging area, resulting in high-fidelity spatial transcriptomics data. Using a predesigned 379-gene mouse panel, we identified 40 major lung cell types. We detected key cellular changes in PH, including an increase in arterial endothelial cells (AECs) and fibroblasts, alongside a reduction in capillary endothelial cells (CAP1 and CAP2). Through differential gene expression analysis, we observed markers of endothelial-to-mesenchymal transition and fibroblast activation in PH lungs. High-resolution spatial mapping further confirmed increased arterialization in the distal microvasculature. These findings underscore the utility of spatial transcriptomics in preserving the native tissue architecture and enhancing our understanding of cellular heterogeneity in disease. Our protocol provides a reliable method for integrating spatial and transcriptomic data using fixed frozen lung tissues, offering significant potential for future studies in complex diseases such as PH.

Lung cancer represents a significant burden on global health, necessitating the need for new and effective treatment strategies that expand our current therapeutic repertoire. Immunotherapy, namely immune checkpoint blockade (ICB), has revolutionized lung cancer therapy over the last decade by invigorating anti-tumor T cell responses to prolong survival and quality of life. However, not all patients benefit from ICB, emphasizing the need for novel immunotherapeutic strategies that engage other immune functionalities to offer synergy with already available therapies. There has been a longstanding interest in deploying lung cancer vaccines to generate or enhance tumor antigen-specific T cell responses for greater tumor control. Thus far, success has been limited to early-stage clinical trials, where safety, generation of antigen-specific T cell responses in blood sampling, and some patient benefits have been established. Moving forward, the establishment of widespread clinical success in large-scale trials is a necessity to bring lung cancer vaccines into the therapeutic arsenal. In this review, we examine the logic and mechanisms behind therapeutic lung cancer vaccines, before critically and iteratively examining past and current attempts in lung cancer vaccinology. We also look at early pre-clinical studies and outline the future for therapeutic lung cancer vaccines.

Background: Deficiency of surfactant protein-C (SPC) increases susceptibility to lung infections and injury, and suppressed expression of SPC has been associated with the severity of acute respiratory distress syndrome (ARDS). Alveolar type 2 epithelial cells (AT2) are critical for maintenance and repair of the lung. However, the role of the SPC in the regulation of AT2 cell lineage and the underlying mechanisms are not completely understood.

Methods: This study aimed to investigate the mechanisms by which SPC regulates AT2 lineages. Sftpc-/- mice were used to model the SPC deficiency in ARDS patients. We utilized three-dimensional (3D) organoids to compare AT2 lineage characteristics between wild type (WT) and Sftpc-/- mice by analyzing AT2 proliferation, alveolar type 1 cells (AT1) differentiation and CD74 expression, using colony-formation assay, immunofluorescence, flow cytometry, and immunoblots.

Results: The results showed that Sftpc-/- mice demonstrated a reduced AT2 cell population. Influenza A virus subtype H1N1 (H1N1) infected Sftpc-/- mice demonstrated reduced AT2 proliferation and AT1 differentiation. Western blot indicated elevated levels of CD74 protein in AT2 cells of Sftpc-/- mice. Colony-forming efficiency was significantly attenuated in AT2 cells isolated from Sftpc-/- mice compared to the WT controls. Podoplanin (PDPN, a marker of AT1 cells) expression and transient cell count significantly increased in Sftpc-/- organoids. Moreover, siRNA-mediated gene silencing of CD74 in AT2 cells significantly increased AT2 proliferation and AT1 differentiation in Sftpc-/- organoids.

Conclusions: This study suggests that SPC regulates AT2 lineage in vitro and in vivo. The SPC might influence AT2 lineage during the lung epithelium repair by activating signaling mechanism involving CD74 receptor.

Heart failure (HF) is a common clinical syndrome marked by reduced cardiac output, elevated intracardiac pressures, and heart dysfunction. Chronic HF (CHF) is a syndrome characterized by a lack of blood flow and impaired pumping ability to the heart over time, while acute HF (AHF) arises suddenly due to incidents like myocardial infarction or cardiac arrest. HF has a significant impact on pulmonary health and function, leading to conditions such as pulmonary edema and restrictive lung patterns. Clinical evidence highlights the bidirectional relationship between HF and lung dysfunction. Declining lung function serves as a predictor for HF progression and severity, while HF contributes to worsening lung health. Animal models that induce HF through surgical methods further demonstrate the connection between heart and lung pathology. The main mechanisms linking HF and lung dysfunction are pressure overload and chronic systemic inflammation, with changes in the extracellular matrix (ECM) also playing a role. Additionally, environmental factors like air pollution exacerbate lung inflammation, increasing the risk of both HF and chronic obstructive pulmonary disease (COPD) incidence. Combined treatment approaches involving pharmaceutical drugs such as statins, Angiotensin-converting enzyme (ACE) inhibitors, and Angiotensin receptor blockers (ARBs) may benefit by reducing inflammation. This review will explore the complex interplay between HF and lung function, emphasizing their interconnected pathophysiology and potential integrated treatment strategies.