Pabelick, Christina M.

EndMT has been reported to contribute to the pathogenesis of PAH. In this study, we aimed to determine the role of Ca 2+ signaling in the development of EndMT in human lung vascular endothelial cells. Our data suggest that TGF-β 1 requires store-operated Ca 2+ entry through STIM1/Orai channels to induce SNAI-mediated EndMT. For the first time, we demonstrated that TGF-β 1 -induced EndMT is a Ca 2+ -dependent event, whereas inhibition of STIM1/Orai interaction attenuated EndMT in response to TGF-β 1 .

Supplemental O 2 (hyperoxia) in premature infants detrimentally affects bronchial airways leading to increased senescence. Understanding the mechanisms by which hyperoxia initiates senescence in developing airways is critical for future therapeutic strategies. The current study showed that hyperoxia-induced senescence is mediated through increased mitochondrial reactive oxygen species and endoplasmic reticulum (ER) stress. ER stress inhibitors or mitochondria-targeted antioxidants may represent future therapies to blunt detrimental effects of supplemental oxygen in developing lungs.

Abstract The lung is an inherently mechanosensitive organ, where cells of the airway and parenchyma experience a range of mechanical forces throughout life including shear, stretch, and compression, in both health and disease. In this regard, pediatric and adult lung diseases such as wheezing and asthma, bronchopulmonary dysplasia (BPD), chronic obstructive pulmonary disease (COPD), and pulmonary fibrosis (PF) all involve macroscopic and cellular changes to the mechanical properties of the bronchial airways and/or parenchyma to varying extents. Accordingly, understanding how mechanical forces are sensed in the lung, and the responses of cells and tissues in the context of normal development and health versus disease conditions becomes highly relevant. There is increasing recognition that transduction of mechanical forces into cellular responses involves a number of channels, some of which are inherently mechanosensitive. Such channels trigger mechanotransduction pathways that may further mediate cellular remodeling, inflammation, and other pathophysiologic mechanisms in response to stretch, stiffness, and inflammatory cascades. Two particularly important channel families have emerged in pulmonary pathophysiology: the transient receptor potential vanilloid family with focus on member TRPV4 and the recently identified Piezo (PZ) channels. Here, we explore current understanding of the contributions of TRPV4 and PZ channels in lung health and disease states, focusing on the interactions between these mechanosensitive channels and their local environment including immune cells, the extracellular matrix, and cellular cytoskeletal elements. We further discuss potential areas for future research to better understand the impact of mechanical channels on pulmonary health and disease. © 2023 American Physiological Society. Compr Physiol 13:5157‐5178, 2023.

Abstract Human chromosomal anomalies, notably trisomies, disrupt gene expression, leading to diverse cellular and organ phenotypes. Increased cellular senescence (SEN) and oxidative stress in trisomies have gained recent attention. We assessed SEN, SEN-associated secretory phenotype (SASP), and oxidative stress on trisomy 13 (T13), T18, and T21 human fetal lung tissues and isolated primary human fetal lung fibroblasts. Telomerase-associated foci staining showed DNA damage primarily within T21 and T18 lungs. These results were confirmed by real-time quantitative PCR showing an increase of the SEN marker CDKN2B and SASP markers IL-6 and CXCL8. In contrast, lung tissues from T13 showed an upregulation of CDKN2A, whereas no significant changes in SASP marker genes were observed. γ-H2AX (H2A histone family member X) was upregulated in each genotype, particularly in T21. Isolated fibroblasts demonstrated a strong association between T21 and several SEN markers. An increase of γ-H2AX–positive cells were observed in fibroblasts from T21, T18, and T13, but only T21 exhibited an increase in P21 expression. Only T21 fibroblasts displayed a significant increase in reactive oxygen species levels, as indicated by MitoSOX and CellROX. This study provides the first evidence of a link between SEN and trisomy anomalies during prenatal human lung development, particularly in T21.

Asthma is a heterogeneous chronic lung disease that affects nearly 340 million people globally. Airway hyperresponsiveness, remodeling (thickening and fibrosis), and mucus hypersecretion are some hallmarks of asthma. With several current treatments having serious side effects from long-term use and a proportion of patients with uncontrolled asthma, there is an urgent need for new therapies. With an increasing understanding of asthma pathophysiology, there is a recognized need to target therapies to specific cell types of the airway, which necessitates the identification of delivery systems that can overcome increased mucus and thickened airways. Nanoparticles (NPs) that are highly customizable (material, size, charge, and surface modification) are a potential solution for delivery systems of a wide variety of cargoes (nucleic acids, proteins, and/or small molecules), as well as sole therapeutics for asthma. However, there is a need to consider the safety of the NPs in terms of potential for inflammation, toxicity, nonspecific targets, and accumulation in organs. Ongoing clinical trials using NPs, some FDA-approved for therapeutics in other diseases, provide confidence regarding the potential safety and efficacy of NPs in asthma treatment. This review highlights the current state of the use of NPs in asthma, identifying opportunities for further improvements in NP design and utilization for targeting this chronic lung disease.

The pathogenesis of asthma in elderly is not well understood. Using a mouse model of asthma, we show that aging results in decreased lung function and less responsiveness to allergen exposure, impacted by locally produced brain-derived neurotrophic factor. Aging also decreases allergen-induced inflammation but increases airway remodeling and senescence. Our results suggest that senescence pathways may contribute to asthma pathogenesis in elderly.

Our previous study suggests that glial-derived neurotrophic factor (GDNF) is involved in allergen-induced airway hyperreactivity and remodeling in vivo. Here, we show that GDNF has no direct effects in remodeling of human airway smooth muscle (ASM) but GDNF dysregulates mitochondrial morphology in human ASM in the context of asthma.

Abstract Nicotine exposure in the context of smoking or vaping worsens airway function. Although nicotinic acetylcholine receptors (nAChRs) are commonly thought to exert effects through the peripheral nervous system, we previously showed that airway smooth muscle (ASM) expresses them, particularly α7 subtype nAChR (α7nAChR), with functional effects on contractility and metabolism. However, the mechanisms of nAChR regulation and downstream effects in ASM are not fully understood. Using ASM cells from people without asthma versus people with mild to moderate asthma, we tested the hypothesis that nAChR-specific endoplasmic reticulum (ER) chaperones, resistance to inhibitors of cholinesterase 3 (RIC-3) and transmembrane protein 35A (TMEM35A) promote cell surface localization of α7nAChR with downstream influence on its functionality: effects exacerbated by inflammation. We found that mild to moderate asthma and exposure to proinflammatory cytokines relevant to asthma promote chaperone and α7nAChR expression in ASM. Downstream, ER stress was linked to nicotine/α7nAChR signaling, where RIC-3 and TMEM35 regulate nicotine-induced ER stress, intracellular Ca2+ regulation, and ASM cell proliferation. Overall, our data highlight the importance α7nAChR chaperones in mediating and modulating nicotine effects in ASM toward airway contractility and remodeling.

The lung is an inherently mechanosensitive organ that can respond to mechanical forces in adaptive or maladaptive ways, including via remodeling resulting in increased fibrosis. We explored the mechanisms that link mechanical forces to remodeling using human lung fibroblasts. We found that mechanosensitive Piezo channels increase with stretch and mediate extracellular matrix formation and the fibroblast-to-myofibroblast transition that occurs with stretch. Our data highlight the importance of Piezo channels in lung mechanotransduction toward remodeling.

AbstractSupplemental O2 (hyperoxia) is a critical intervention for premature infants (<34 weeks) but consequently is associated with development of bronchial airway hyperreactivity (AHR) and asthma. Clinical practice shifted toward the use of moderate hyperoxia (<60% O2), but risk for subsequent airway disease remains. In mouse models of moderate hyperoxia, neonatal mice have increased AHR with effects on airway smooth muscle (ASM), a cell type involved in airway tone, bronchodilation, and remodeling. Understanding mechanisms by which moderate O2 during the perinatal period initiates sustained airway changes is critical to drive therapeutic advancements toward treating airway diseases. We propose that cellular clock factor BMAL1 is functionally important in developing mouse airways. In adult mice, cellular clocks target pathways highly relevant to asthma pathophysiology and Bmal1 deletion increases inflammatory response, worsens lung function, and impacts survival outcomes. Our understanding of BMAL1 in the developing lung is limited, but our previous findings show functional relevance of clocks in human fetal ASM exposed to O2. Here, we characterize Bmal1 in our established mouse neonatal hyperoxia model. Our data show that Bmal1 KO deleteriously impacts the developing lung in the context of O2 and these data highlight the importance of neonatal sex in understanding airway disease.