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Pérez-Pérez A, González-Pacheco N, Arriaga-Redondo M, Ramos-Navarro C, Rodríguez-Corrales E, de la Blanca ARS, González-Navarro P, Santos-González M, Sánchez-Luna M. Impact on cerebral hemodynamics of the use of volume guarantee combined with high frequency oscillatory ventilation in a neonatal animal respiratory distress model. Eur J Pediatr 2024; 183:157-167. [PMID: 37851085 DOI: 10.1007/s00431-023-05245-0] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/24/2023] [Revised: 09/22/2023] [Accepted: 09/28/2023] [Indexed: 10/19/2023]
Abstract
High-frequency oscillatory ventilation (HFOV) is an alternative to conventional mechanical ventilation (CMV). Recently, the use of volume guarantee (VG) combined with HFOV has been suggested as a safe strategy capable of reducing the damage induced by ventilation in immature lungs. However, the possible impact of this new ventilation technique on cerebral hemodynamics is unknown. To evaluate the cerebral hemodynamics effect of HFOV combined with VG in an experimental animal model of neonatal respiratory distress syndrome (RDS) due to surfactant deficiency compared with HFOV and CMV+VG (control group). Eighteen newborn piglets were randomized, before and after the induction of RDS by bronchoalveolar lavage, into 3 mechanical ventilation groups: CMV, HFOV and HFOV with VG. Changes in cerebral oxygen transport and consumption and cerebral blood flow were analyzed by non-invasive regional cerebral oxygen saturation (CrSO2), jugular venous saturation (SjO2), the calculated cerebral oxygen extraction fraction (COEF), the calculated cerebral fractional tissue oxygen extraction (cFTOE) and direct measurement of carotid artery flow. To analyze the temporal evolution of these variables, a mixed-effects linear regression model was constructed. After randomization, the following statistically significant results were found in every group: a drop in carotid artery flow: at a rate of -1.7 mL/kg/min (95% CI: -2.5 to -0.81; p < 0.001), CrSO2: at a rate of -6.2% (95% CI: -7.9 to -4.4; p < 0.001) and SjO2: at a rate of -20% (95% CI: -26 to -15; p < 0.001), accompanied by an increase in COEF: at a rate of 20% (95% CI: 15 to 26; p < 0.001) and cFTOE: at a rate of 0.07 (95% CI: 0.05 to 0.08; p < 0.001) in all groups. No statistically significant differences were found between the HFOV groups. CONCLUSION No differences were observed at cerebral hemodynamic between respiratory assistance in HFOV with and without VG, being the latter ventilatory strategy equally safe. WHAT IS KNOWN • Preterm have a situation of fragility of cerebral perfusion wich means that any mechanical ventilation strategy can have a significant influence. High-frequency oscillatory ventilation (HFOV) is an alternative to conventional mechanical ventilation (CMV). Recently, the use of volume guarantee (VG) combined with HFOV has been suggested as a safe strategy capable of reducing the damage induced by ventilation in immature lungs. Several studies have compared CMV and HFOV and their effects at hemodynamic level. It is known that the use of high mean airway pressure in HFOV can cause an increase in pulmonary vascular resistance with a decrease in thoracic venous return. WHAT IS NEW • The possible impact of VAFO + VG on cerebral hemodynamics is unknown. Due the lack of studies and the existing controversy, we have carried out this research project in an experimental animal model with the aim of evaluating the cerebral hemodynamic repercussion of the use of VG in HFOV compared to the classic strategy without VG.
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Affiliation(s)
- Alba Pérez-Pérez
- Neonatology Department, Hospital General Universitario Gregorio Marañón, c/ O'Donnell, 48, CP 28009, Madrid, Spain.
| | - Noelia González-Pacheco
- Neonatology Department, Hospital General Universitario Gregorio Marañón, c/ O'Donnell, 48, CP 28009, Madrid, Spain
| | - María Arriaga-Redondo
- Neonatology Department, Hospital General Universitario Gregorio Marañón, c/ O'Donnell, 48, CP 28009, Madrid, Spain
| | - Cristina Ramos-Navarro
- Neonatology Department, Hospital General Universitario Gregorio Marañón, c/ O'Donnell, 48, CP 28009, Madrid, Spain
| | - Elena Rodríguez-Corrales
- Neonatology Department, Hospital General Universitario Gregorio Marañón, c/ O'Donnell, 48, CP 28009, Madrid, Spain
| | | | - Pablo González-Navarro
- Unidad de Investigación Materno Infantil Fundación Familia Alonso (UDIMIFFA) - Instituto de Investigación Sanitaria Gregorio Marañón (IiSGM), Madrid, Spain
| | - Martín Santos-González
- Medical and Surgical Research Unit, Instituto de Investigación Sanitaria Puerta de Hierro, Hospital Universitario Puerta de Hierro, Majadahonda, Madrid, Spain
| | - Manuel Sánchez-Luna
- Neonatology Department, Hospital General Universitario Gregorio Marañón, c/ O'Donnell, 48, CP 28009, Madrid, Spain
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Toth A, Kannan P, Snowball J, Kofron M, Wayman JA, Bridges JP, Miraldi ER, Swarr D, Zacharias WJ. Alveolar epithelial progenitor cells require Nkx2-1 to maintain progenitor-specific epigenomic state during lung homeostasis and regeneration. Nat Commun 2023; 14:8452. [PMID: 38114516 PMCID: PMC10775890 DOI: 10.1038/s41467-023-44184-0] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/22/2022] [Accepted: 12/04/2023] [Indexed: 12/21/2023] Open
Abstract
Lung epithelial regeneration after acute injury requires coordination cellular coordination to pattern the morphologically complex alveolar gas exchange surface. During adult lung regeneration, Wnt-responsive alveolar epithelial progenitor (AEP) cells, a subset of alveolar type 2 (AT2) cells, proliferate and transition to alveolar type 1 (AT1) cells. Here, we report a refined primary murine alveolar organoid, which recapitulates critical aspects of in vivo regeneration. Paired scRNAseq and scATACseq followed by transcriptional regulatory network (TRN) analysis identified two AT1 transition states driven by distinct regulatory networks controlled in part by differential activity of Nkx2-1. Genetic ablation of Nkx2-1 in AEP-derived organoids was sufficient to cause transition to a proliferative stressed Krt8+ state, and AEP-specific deletion of Nkx2-1 in adult mice led to rapid loss of progenitor state and uncontrolled growth of Krt8+ cells. Together, these data implicate dynamic epigenetic maintenance via Nkx2-1 as central to the control of facultative progenitor activity in AEPs.
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Affiliation(s)
- Andrea Toth
- Perinatal Institute, Cincinnati Children's Hospital Medical Center, Cincinnati, OH, USA
- Division of Pulmonary Biology, Cincinnati Children's Hospital Medical Center, Cincinnati, OH, USA
- Division of Developmental Biology, Cincinnati Children's Hospital Medical Center, Cincinnati, OH, USA
- Medical Scientist Training Program, University of Cincinnati College of Medicine, Cincinnati, OH, USA
- Molecular and Developmental Biology Graduate Program, University of Cincinnati College of Medicine, Cincinnati, OH, USA
| | - Paranthaman Kannan
- Perinatal Institute, Cincinnati Children's Hospital Medical Center, Cincinnati, OH, USA
- Division of Pulmonary Biology, Cincinnati Children's Hospital Medical Center, Cincinnati, OH, USA
- Division of Developmental Biology, Cincinnati Children's Hospital Medical Center, Cincinnati, OH, USA
| | - John Snowball
- Perinatal Institute, Cincinnati Children's Hospital Medical Center, Cincinnati, OH, USA
- Division of Pulmonary Biology, Cincinnati Children's Hospital Medical Center, Cincinnati, OH, USA
- Division of Developmental Biology, Cincinnati Children's Hospital Medical Center, Cincinnati, OH, USA
| | - Matthew Kofron
- Division of Developmental Biology, Cincinnati Children's Hospital Medical Center, Cincinnati, OH, USA
- Bio-Imaging and Analysis Facility, Cincinnati Children's Hospital Medical Center, Cincinnati, OH, USA
- Department of Pediatrics, University of Cincinnati College of Medicine, Cincinnati, OH, USA
| | - Joseph A Wayman
- Division of Immunology, Cincinnati Children's Hospital Medical Center, Cincinnati, OH, USA
- Division of Biomedical Informatics, Cincinnati Children's Hospital Medical Center, Cincinnati, OH, USA
| | - James P Bridges
- Department of Medicine, Division of Pulmonary Sciences and Critical Care Medicine, University of Colorado Anschutz Medical Campus, Aurora, Colorado, USA
- Department of Medicine, Division of Pulmonary and Critical Care Medicine, National Jewish Health, Denver, Colorado, USA
| | - Emily R Miraldi
- Department of Pediatrics, University of Cincinnati College of Medicine, Cincinnati, OH, USA
- Division of Immunology, Cincinnati Children's Hospital Medical Center, Cincinnati, OH, USA
- Division of Biomedical Informatics, Cincinnati Children's Hospital Medical Center, Cincinnati, OH, USA
| | - Daniel Swarr
- Perinatal Institute, Cincinnati Children's Hospital Medical Center, Cincinnati, OH, USA
- Division of Pulmonary Biology, Cincinnati Children's Hospital Medical Center, Cincinnati, OH, USA
- Department of Pediatrics, University of Cincinnati College of Medicine, Cincinnati, OH, USA
| | - William J Zacharias
- Perinatal Institute, Cincinnati Children's Hospital Medical Center, Cincinnati, OH, USA.
- Division of Pulmonary Biology, Cincinnati Children's Hospital Medical Center, Cincinnati, OH, USA.
- Division of Developmental Biology, Cincinnati Children's Hospital Medical Center, Cincinnati, OH, USA.
- Department of Pediatrics, University of Cincinnati College of Medicine, Cincinnati, OH, USA.
- Division of Pulmonary and Critical Care Medicine, Department of Internal Medicine, University of Cincinnati College of Medicine, Cincinnati, OH, USA.
- Center for Stem Cell and Organoid Medicine, Cincinnati Children's Hospital Medical Center, Cincinnati, OH, USA.
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Fang XZ, Li M, Wang YX, Zhang P, Sun MM, Xu JX, Yang YY, He YJ, Yu Y, Li RT, Zhou T, Reng LH, Sun DY, Shu HQ, Yuan SY, Xu JQ, Shang Y. Mechanosensitive ion channel Piezo1 mediates mechanical ventilation-exacerbated ARDS-associated pulmonary fibrosis. J Adv Res 2023; 53:175-186. [PMID: 36526145 PMCID: PMC10658225 DOI: 10.1016/j.jare.2022.12.006] [Citation(s) in RCA: 10] [Impact Index Per Article: 10.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/27/2022] [Revised: 12/09/2022] [Accepted: 12/10/2022] [Indexed: 12/15/2022] Open
Abstract
INTRODUCTION Pulmonary fibrosis is a major cause of the poor prognosis of acute respiratory distress syndrome (ARDS). While mechanical ventilation (MV) is an indispensable life-saving intervention for ARDS, it may cause the remodeling process in lung epithelial cells to become disorganized and exacerbate ARDS-associated pulmonary fibrosis. Piezo1 is a mechanosensitive ion channel that is known to play a role in regulating diverse physiological processes, but whether Piezo1 is necessary for MV-exacerbated ARDS-associated pulmonary fibrosis remains unknown. OBJECTIVES This study aimed to explore the role of Piezo1 in MV-exacerbated ARDS-associated pulmonary fibrosis. METHODS Human lung epithelial cells were stimulated with hydrochloric acid (HCl) followed by mechanical stretch for 48 h. A two-hitmodel of MV afteracidaspiration-inducedlunginjuryin mice was used. Mice were sacrificed after 14 days of MV. Pharmacological inhibition and knockout of Piezo1 were used to delineate the role of Piezo1 in MV-exacerbated ARDS-associated pulmonary fibrosis. In some experiments, ATP or the ATP-hydrolyzing enzyme apyrase was administered. RESULTS The stimulation of human lung epithelial cells to HCl resulted in phenotypes of epithelial-mesenchymal transition (EMT), which were enhanced by mechanical stretching. MV exacerbated pulmonary fibrosis in mice exposed to HCl. Pharmacologicalinhibitionorknockout of Piezo1 attenuated the MV-exacerbated EMT process and lung fibrosis in vivo and in vitro. Mechanistically, the observed effects were mediated by Piezo1-dependent Ca2+ influx and ATP release in lung epithelial cells. CONCLUSIONS Our findings identify a key role for Piezo1 in MV-exacerbated ARDS-associated pulmonary fibrosis that is mediated by increased ATP release in lung epithelial cells. Inhibiting Piezo1 may constitute a novelstrategyfor the treatment of MV-exacerbated ARDS-associated pulmonary fibrosis.
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Affiliation(s)
- Xiang-Zhi Fang
- Department of Critical Care Medicine, Union Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, China; Institute of Anesthesiology and Critical Care Medicine, Union Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, China
| | - Min Li
- Department of Pain Management, Wuhan No. 1 Hospital, Wuhan, Hubei Province, China
| | - Ya-Xin Wang
- Department of Critical Care Medicine, Union Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, China; Institute of Anesthesiology and Critical Care Medicine, Union Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, China
| | - Pei Zhang
- Department of Paediatrics, Jinling Hospital, School of Medicine, Nanjing University, China
| | - Miao-Miao Sun
- Institute of Anesthesiology and Critical Care Medicine, Union Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, China
| | - Jia-Xin Xu
- Department of Critical Care Medicine, Union Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, China; Institute of Anesthesiology and Critical Care Medicine, Union Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, China
| | - Yi-Yi Yang
- Institute of Anesthesiology and Critical Care Medicine, Union Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, China
| | - Ya-Jun He
- Department of Critical Care Medicine, Union Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, China; Institute of Anesthesiology and Critical Care Medicine, Union Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, China
| | - Yuan Yu
- Department of Critical Care Medicine, Union Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, China; Institute of Anesthesiology and Critical Care Medicine, Union Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, China
| | - Rui-Ting Li
- Department of Critical Care Medicine, Union Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, China; Institute of Anesthesiology and Critical Care Medicine, Union Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, China
| | - Ting Zhou
- Department of Critical Care Medicine, Union Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, China; Institute of Anesthesiology and Critical Care Medicine, Union Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, China
| | - Le-Hao Reng
- Department of Critical Care Medicine, Union Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, China; Institute of Anesthesiology and Critical Care Medicine, Union Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, China
| | - De-Yi Sun
- Department of Critical Care Medicine, Union Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, China; Institute of Anesthesiology and Critical Care Medicine, Union Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, China
| | - Hua-Qing Shu
- Department of Critical Care Medicine, Union Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, China; Institute of Anesthesiology and Critical Care Medicine, Union Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, China
| | - Shi-Ying Yuan
- Department of Critical Care Medicine, Union Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, China; Institute of Anesthesiology and Critical Care Medicine, Union Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, China
| | - Ji-Qian Xu
- Department of Critical Care Medicine, Union Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, China; Institute of Anesthesiology and Critical Care Medicine, Union Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, China.
| | - You Shang
- Department of Critical Care Medicine, Union Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, China; Institute of Anesthesiology and Critical Care Medicine, Union Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, China.
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Knudsen L, Hummel B, Wrede C, Zimmermann R, Perlman CE, Smith BJ. Acinar micromechanics in health and lung injury: what we have learned from quantitative morphology. Front Physiol 2023; 14:1142221. [PMID: 37025383 PMCID: PMC10070844 DOI: 10.3389/fphys.2023.1142221] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/11/2023] [Accepted: 03/09/2023] [Indexed: 04/08/2023] Open
Abstract
Within the pulmonary acini ventilation and blood perfusion are brought together on a huge surface area separated by a very thin blood-gas barrier of tissue components to allow efficient gas exchange. During ventilation pulmonary acini are cyclically subjected to deformations which become manifest in changes of the dimensions of both alveolar and ductal airspaces as well as the interalveolar septa, composed of a dense capillary network and the delicate tissue layer forming the blood-gas barrier. These ventilation-related changes are referred to as micromechanics. In lung diseases, abnormalities in acinar micromechanics can be linked with injurious stresses and strains acting on the blood-gas barrier. The mechanisms by which interalveolar septa and the blood-gas barrier adapt to an increase in alveolar volume have been suggested to include unfolding, stretching, or changes in shape other than stretching and unfolding. Folding results in the formation of pleats in which alveolar epithelium is not exposed to air and parts of the blood-gas barrier are folded on each other. The opening of a collapsed alveolus (recruitment) can be considered as an extreme variant of septal wall unfolding. Alveolar recruitment can be detected with imaging techniques which achieve light microscopic resolution. Unfolding of pleats and stretching of the blood-gas barrier, however, require electron microscopic resolution to identify the basement membrane. While stretching results in an increase of the area of the basement membrane, unfolding of pleats and shape changes do not. Real time visualization of these processes, however, is currently not possible. In this review we provide an overview of septal wall micromechanics with focus on unfolding/folding as well as stretching. At the same time we provide a state-of-the-art design-based stereology methodology to quantify microarchitecture of alveoli and interalveolar septa based on different imaging techniques and design-based stereology.
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Affiliation(s)
- Lars Knudsen
- Institute of Functional and Applied Anatomy, Hannover Medical School, Hannover, Germany
- Biomedical Research in Endstage and Obstructive Lung Disease Hannover (BREATH), Member of the German Centre for Lung Research (DZL), Hannover, Germany
| | - Benjamin Hummel
- Institute of Functional and Applied Anatomy, Hannover Medical School, Hannover, Germany
| | - Christoph Wrede
- Institute of Functional and Applied Anatomy, Hannover Medical School, Hannover, Germany
- Research Core Unit Electron Microscopy, Hannover Medical School, Hannover, Germany
| | - Richard Zimmermann
- Institute of Functional and Applied Anatomy, Hannover Medical School, Hannover, Germany
| | - Carrie E Perlman
- Department of Biomedical Engineering, Stevens Institute of Technology, Hoboken, NJ, United States
| | - Bradford J Smith
- Department of Bioengineering, College of Engineering Design and Computing, University of Colorado Denver | Anschutz Medical Campus, Aurora, CO, United States
- Department of Pediatric Pulmonary and Sleep Medicine, School of Medicine, University of Colorado Anschutz Medical Campus, Aurora, CO, United States
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Yang C, Guo J, Ni K, Wen K, Qin Y, Gu R, Wang C, Liu L, Pan Y, Li J, Luo M, Deng L. Mechanical Ventilation-Related High Stretch Mainly Induces Endoplasmic Reticulum Stress and Thus Mediates Inflammation Response in Cultured Human Primary Airway Smooth Muscle Cells. Int J Mol Sci 2023; 24:ijms24043811. [PMID: 36835223 PMCID: PMC9958795 DOI: 10.3390/ijms24043811] [Citation(s) in RCA: 4] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/24/2022] [Revised: 01/29/2023] [Accepted: 02/03/2023] [Indexed: 02/17/2023] Open
Abstract
Ventilator-induced lung injury (VILI) occurs in mechanically ventilated patients of respiratory disease and is typically characterized by airway inflammation. However, recent studies increasingly indicate that a major cause of VILI may be the excessive mechanical loading such as high stretch (>10% strain) on airway smooth muscle cells (ASMCs) due to mechanical ventilation (MV). Although ASMCs are the primary mechanosensitive cells in airways and contribute to various airway inflammation diseases, it is still unclear how they respond to high stretch and what mediates such a response. Therefore, we used whole genome-wide mRNA-sequencing (mRNA-Seq), bioinformatics, and functional identification to systematically analyze the mRNA expression profiles and signaling pathway enrichment of cultured human ASMCs exposed to high stretch (13% strain), aiming to screen the susceptible signaling pathway through which cells respond to high stretch. The data revealed that in response to high stretch, 111 mRNAs with count ≥100 in ASMCs were significantly differentially expressed (defined as DE-mRNAs). These DE-mRNAs are mainly enriched in endoplasmic reticulum (ER) stress-related signaling pathways. ER stress inhibitor (TUDCA) abolished high-stretch-enhanced mRNA expression of genes associated with ER stress, downstream inflammation signaling, and major inflammatory cytokines. These results demonstrate in a data-driven approach that in ASMCs, high stretch mainly induced ER stress and activated ER stress-related signaling and downstream inflammation response. Therefore, it suggests that ER stress and related signaling pathways in ASMCs may be potential targets for timely diagnosis and intervention of MV-related pulmonary airway diseases such as VILI.
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Affiliation(s)
| | | | | | | | | | | | | | | | | | | | - Mingzhi Luo
- Correspondence: (M.L.); (L.D.); Tel.: +86-136-1611-9565 (M.L.); +86-136-8520-7009 (L.D.)
| | - Linhong Deng
- Correspondence: (M.L.); (L.D.); Tel.: +86-136-1611-9565 (M.L.); +86-136-8520-7009 (L.D.)
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Rosmark O, Ibáñez-Fonseca A, Thorsson J, Dellgren G, Hallgren O, Larsson Callerfelt AK, Elowsson L, Westergren-Thorsson G. A tunable physiomimetic stretch system evaluated with precision cut lung slices and recellularized human lung scaffolds. Front Bioeng Biotechnol 2022; 10:995460. [PMID: 36263353 PMCID: PMC9574011 DOI: 10.3389/fbioe.2022.995460] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/15/2022] [Accepted: 09/13/2022] [Indexed: 11/13/2022] Open
Abstract
Breathing exposes lung cells to continual mechanical stimuli, which is part of the microenvironmental signals directing cellular functions together with the extracellular matrix (ECM). Therefore, developing systems that incorporate both stimuli is urgent to fully understand cell behavior. This study aims to introduce a novel in vitro culture methodology combining a cyclic stretch that simulates in vivo breathing with 3D cell culture platforms in the form of decellularized lung slices (DLS) and precision cut lung slices (PCLS). To this end, we have constructed a device that mimics the amplitudes and frequencies of distensions seen in the breathing human lung. For its validation, we cultured H441 lung epithelial cells in human DLS exposed to 16 stretch cycles per minute with a 10% stretch amplitude. Cell viability (resazurin reduction), proliferation (Ki-67) and YAP1 activation were evaluated at 24 and 96 h by immunohistochemistry, while the expression of SFTPB, COL3A1, COL4A3 and LAMA5 was evaluated by qPCR. Cyclic stretch induced an increase in SFTPB expression after 24 h without a concomitant increase in the stretch responsive gene YAP1. Moreover, the ECM milieu lowered the expression of the basement membrane protein genes COL4A3 and LAMA5 compared to tissue culture plastic control cultures, but no effect was observed by the mechanical stimuli. The device also confirmed good compatibility with PCLS culture, showing preserved morphology and metabolism in rat PCLS after 72 h of mechanical stretch. Thus, we present a novel device and methodology for the easy assembling and study of lung tissue slice cultures subjected to physiomimetic mechanical stimuli, which shows promise for future studies of cell and tissue function in a lung ECM milieu with physiological or pathological mechanical stimuli.
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Affiliation(s)
- Oskar Rosmark
- Lung Biology, Department of Experimental Medical Science, Lund University, Lund, Sweden
| | - Arturo Ibáñez-Fonseca
- Lung Biology, Department of Experimental Medical Science, Lund University, Lund, Sweden
- *Correspondence: Arturo Ibáñez-Fonseca,
| | - Johan Thorsson
- Lung Biology, Department of Experimental Medical Science, Lund University, Lund, Sweden
| | - Göran Dellgren
- Transplant Institute and Department of Cardiothoracic Surgery, Sahlgrenska University Hospital, Gothenburg, Sweden
| | - Oskar Hallgren
- Division of Thoracic Surgery, Department of Clinical Sciences, Lund University, Lund, Sweden
| | | | - Linda Elowsson
- Lung Biology, Department of Experimental Medical Science, Lund University, Lund, Sweden
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Godbole NM, Chowdhury AA, Chataut N, Awasthi S. Tight Junctions, the Epithelial Barrier, and Toll-like Receptor-4 During Lung Injury. Inflammation 2022; 45:2142-2162. [PMID: 35779195 DOI: 10.1007/s10753-022-01708-y] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/24/2022] [Revised: 05/31/2022] [Accepted: 06/13/2022] [Indexed: 11/25/2022]
Abstract
Lung epithelium is constantly exposed to the environment and is critically important for the orchestration of initial responses to infectious organisms, toxins, and allergic stimuli, and maintenance of normal gaseous exchange and pulmonary function. The integrity of lung epithelium, fluid balance, and transport of molecules is dictated by the tight junctions (TJs). The TJs are formed between adjacent cells. We have focused on the topic of the TJ structure and function in lung epithelial cells. This review includes a summary of the last twenty years of literature reports published on the disrupted TJs and epithelial barrier in various lung conditions and expression and regulation of specific TJ proteins against pathogenic stimuli. We discuss the molecular signaling and crosstalk among signaling pathways that control the TJ structure and function. The Toll-like receptor-4 (TLR4) recognizes the pathogen- and damage-associated molecular patterns released during lung injury and inflammation and coordinates cellular responses. The molecular aspects of TLR4 signaling in the context of TJs or the epithelial barrier are not fully known. We describe the current knowledge and possible networking of the TLR4-signaling with cellular and molecular mechanisms of TJs, lung epithelial barrier function, and resistance to treatment strategies.
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Affiliation(s)
- Nachiket M Godbole
- Department of Pharmaceutical Sciences, College of Pharmacy, University of Oklahoma Health Sciences Center, 1110 N. Stonewall Avenue, Oklahoma City, OK, 73117, USA
| | - Asif Alam Chowdhury
- Department of Pharmaceutical Sciences, College of Pharmacy, University of Oklahoma Health Sciences Center, 1110 N. Stonewall Avenue, Oklahoma City, OK, 73117, USA
| | - Neha Chataut
- Department of Pharmaceutical Sciences, College of Pharmacy, University of Oklahoma Health Sciences Center, 1110 N. Stonewall Avenue, Oklahoma City, OK, 73117, USA
| | - Shanjana Awasthi
- Department of Pharmaceutical Sciences, College of Pharmacy, University of Oklahoma Health Sciences Center, 1110 N. Stonewall Avenue, Oklahoma City, OK, 73117, USA.
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Ge X, He Z, Cao C, Xue T, Jing J, Ma R, Zhao W, Liu L, Jueraitetibaike K, Ma J, Feng Y, Qian Z, Zou Z, Chen L, Fu C, Song N, Yao B. Protein palmitoylation-mediated palmitic acid sensing causes blood-testis barrier damage via inducing ER stress. Redox Biol 2022; 54:102380. [PMID: 35803125 PMCID: PMC9287734 DOI: 10.1016/j.redox.2022.102380] [Citation(s) in RCA: 10] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/13/2022] [Revised: 06/16/2022] [Accepted: 06/20/2022] [Indexed: 11/25/2022] Open
Abstract
Blood-testis barrier (BTB) damage promotes spermatogenesis dysfunction, which is a critical cause of male infertility. Dyslipidemia has been correlated with male infertility, but the major hazardous lipid and the underlying mechanism remains unclear. In this study, we firstly discovered an elevation of palmitic acid (PA) and a decrease of inhibin B in patients with severe dyszoospermia, which leaded us to explore the effects of PA on Sertoli cells. We observed a damage of BTB by PA. PA penetration to endoplasmic reticulum (ER) and its damage to ER structures were exhibited by microimaging and dynamic observation, and consequent ER stress was proved to mediate PA-induced Sertoli cell barrier disruption. Remarkably, we demonstrated a critical role of aberrant protein palmitoylation in PA-induced Sertoli cell barrier dysfunction. An ER protein, Calnexin, was screened out and was demonstrated to participate in this process, and suppression of its palmitoylation showed an ameliorating effect. We also found that ω-3 poly-unsaturated fatty acids down-regulated Calnexin palmitoylation, and alleviated BTB dysfunction. Our results indicate that dysregulated palmitoylation induced by PA plays a pivotal role in BTB disruption and subsequent spermatogenesis dysfunction, suggesting that protein palmitoylation might be therapeutically targetable in male infertility. An elevation of circulating PA was identified in patients with severe dyszoospermia. PA-induced over-palmitoylation in Sertoli cells leads to ER stress and BTB damage. The palmitoylation of the ER protein Calnexin regulates Sertoli cell barrier function. ω-3 PUFAs ameliorate PA-induced damage and over-palmitoylation in Sertoli cells.
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9
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Martín-Vicente P, López-Martínez C, Lopez-Alonso I, López-Aguilar J, Albaiceta GM, Amado-Rodríguez L. Molecular mechanisms of postintensive care syndrome. Intensive Care Med Exp 2021; 9:58. [PMID: 34859298 PMCID: PMC8639215 DOI: 10.1186/s40635-021-00423-6] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/23/2021] [Accepted: 11/16/2021] [Indexed: 11/10/2022] Open
Affiliation(s)
- Paula Martín-Vicente
- Instituto de Investigación Sanitaria del Principado de Asturias, Oviedo, Spain.,Centro de Investigación Biomédica en Red (CIBER)-Enfermedades Respiratorias, Madrid, Spain
| | - Cecilia López-Martínez
- Instituto de Investigación Sanitaria del Principado de Asturias, Oviedo, Spain.,Centro de Investigación Biomédica en Red (CIBER)-Enfermedades Respiratorias, Madrid, Spain
| | - Inés Lopez-Alonso
- Instituto de Investigación Sanitaria del Principado de Asturias, Oviedo, Spain.,Centro de Investigación Biomédica en Red (CIBER)-Enfermedades Respiratorias, Madrid, Spain.,Instituto Universitario de Oncología del Principado de Asturias, Universidad de Oviedo, Oviedo, Spain
| | - Josefina López-Aguilar
- Centro de Investigación Biomédica en Red (CIBER)-Enfermedades Respiratorias, Madrid, Spain.,Critical Care Center, Hospital Universitari Parc Taulí, Institut d'Investigació I Innovació Parc Taulí I3PT, Sabadell, Spain
| | - Guillermo M Albaiceta
- Instituto de Investigación Sanitaria del Principado de Asturias, Oviedo, Spain. .,Centro de Investigación Biomédica en Red (CIBER)-Enfermedades Respiratorias, Madrid, Spain. .,Instituto Universitario de Oncología del Principado de Asturias, Universidad de Oviedo, Oviedo, Spain. .,Unidad de Cuidados Intensivos Cardiológicos, Hospital Universitario Central de Asturias, Oviedo, Spain.
| | - Laura Amado-Rodríguez
- Instituto de Investigación Sanitaria del Principado de Asturias, Oviedo, Spain. .,Centro de Investigación Biomédica en Red (CIBER)-Enfermedades Respiratorias, Madrid, Spain. .,Instituto Universitario de Oncología del Principado de Asturias, Universidad de Oviedo, Oviedo, Spain. .,Unidad de Cuidados Intensivos Cardiológicos, Hospital Universitario Central de Asturias, Oviedo, Spain.
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10
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AMPK activates Parkin independent autophagy and improves post sepsis immune defense against secondary bacterial lung infections. Sci Rep 2021; 11:12387. [PMID: 34117280 PMCID: PMC8196038 DOI: 10.1038/s41598-021-90573-0] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/25/2020] [Accepted: 05/12/2021] [Indexed: 02/06/2023] Open
Abstract
Metabolic and bioenergetic plasticity of immune cells is essential for optimal responses to bacterial infections. AMPK and Parkin ubiquitin ligase are known to regulate mitochondrial quality control mitophagy that prevents unwanted inflammatory responses. However, it is not known if this evolutionarily conserved mechanism has been coopted by the host immune defense to eradicate bacterial pathogens and influence post-sepsis immunosuppression. Parkin, AMPK levels, and the effects of AMPK activators were investigated in human leukocytes from sepsis survivors as well as wild type and Park2−/− murine macrophages. In vivo, the impact of AMPK and Parkin was determined in mice subjected to polymicrobial intra-abdominal sepsis and secondary lung bacterial infections. Mice were treated with metformin during established immunosuppression. We showed that bacteria and mitochondria share mechanisms of autophagic killing/clearance triggered by sentinel events that involve depolarization of mitochondria and recruitment of Parkin in macrophages. Parkin-deficient mice/macrophages fail to form phagolysosomes and kill bacteria. This impairment of host defense is seen in the context of sepsis-induced immunosuppression with decreased levels of Parkin. AMPK activators, including metformin, stimulate Parkin-independent autophagy and bacterial killing in leukocytes from post-shock patients and in lungs of sepsis-immunosuppressed mice. Our results support a dual role of Parkin and AMPK in the clearance of dysfunctional mitochondria and killing of pathogenic bacteria, and explain the immunosuppressive phenotype associated Parkin and AMPK deficiency. AMPK activation appeared to be a crucial therapeutic target for the macrophage immunosuppressive phenotype and to reduce severity of secondary bacterial lung infections and respiratory failure.
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11
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Mathematical modeling of ventilator-induced lung inflammation. J Theor Biol 2021; 526:110738. [PMID: 33930440 DOI: 10.1016/j.jtbi.2021.110738] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/23/2020] [Revised: 04/20/2021] [Accepted: 04/22/2021] [Indexed: 12/13/2022]
Abstract
Despite the benefits of mechanical ventilators, prolonged or misuse of ventilators may lead to ventilation-associated/ventilation-induced lung injury (VILI). Lung insults, such as respiratory infections and lung injuries, can damage the pulmonary epithelium, with the most severe cases needing mechanical ventilation for effective breathing and survival. Damaged epithelial cells within the alveoli trigger a local immune response. A key immune cell is the macrophage, which can differentiate into a spectrum of phenotypes ranging from pro- to anti-inflammatory. To gain a greater understanding of the mechanisms of the immune response to VILI and post-ventilation outcomes, we developed a mathematical model of interactions between the immune system and site of damage while accounting for macrophage phenotype. Through Latin hypercube sampling we generated a collection of parameter sets that are associated with a numerical steady state. We then simulated ventilation-induced damage using these steady state values as the initial conditions in order to evaluate how baseline immune state and lung health affect outcomes. We used a variety of methods to analyze the resulting parameter sets, transients, and outcomes, including a random forest decision tree algorithm and parameter sensitivity with eFAST. Analysis shows that parameters and properties of transients related to epithelial repair and M1 activation are important factors. Using the results of this analysis, we hypothesized interventions and used these treatment strategies to modulate the response to ventilation for particular parameters sets.
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12
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Emanuelli G, Nassehzadeh-Tabriz N, Morrell NW, Marciniak SJ. The integrated stress response in pulmonary disease. Eur Respir Rev 2020; 29:29/157/200184. [PMID: 33004527 PMCID: PMC7116220 DOI: 10.1183/16000617.0184-2020] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/08/2020] [Accepted: 07/15/2020] [Indexed: 02/07/2023] Open
Abstract
The respiratory tract and its resident immune cells face daily exposure
to stress, both from without and from within. Inhaled pathogens, including
severe acute respiratory syndrome coronavirus 2, and toxins from pollution
trigger a cellular defence system that reduces protein synthesis to minimise
viral replication or the accumulation of misfolded proteins. Simultaneously, a
gene expression programme enhances antioxidant and protein folding machineries
in the lung. Four kinases (PERK, PKR, GCN2 and HRI) sense a diverse range of
stresses to trigger this “integrated stress response”. Here we review recent
advances identifying the integrated stress response as a critical pathway in the
pathogenesis of pulmonary diseases, including pneumonias, thoracic malignancy,
pulmonary fibrosis and pulmonary hypertension. Understanding the integrated
stress response provides novel targets for the development of therapies.
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Affiliation(s)
- Giulia Emanuelli
- Cambridge Institute for Medical Research (CIMR), University of Cambridge, Cambridge, UK.,Division of Respiratory Medicine, Dept of Medicine, University of Cambridge, Cambridge, UK.,Equal first authors
| | - Nikou Nassehzadeh-Tabriz
- Cambridge Institute for Medical Research (CIMR), University of Cambridge, Cambridge, UK.,Equal first authors
| | - Nick W Morrell
- Division of Respiratory Medicine, Dept of Medicine, University of Cambridge, Cambridge, UK
| | - Stefan J Marciniak
- Cambridge Institute for Medical Research (CIMR), University of Cambridge, Cambridge, UK .,Division of Respiratory Medicine, Dept of Medicine, University of Cambridge, Cambridge, UK
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13
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Albert K, Krischer JM, Pfaffenroth A, Wilde S, Lopez-Rodriguez E, Braun A, Smith BJ, Knudsen L. Hidden Microatelectases Increase Vulnerability to Ventilation-Induced Lung Injury. Front Physiol 2020; 11:530485. [PMID: 33071807 PMCID: PMC7530907 DOI: 10.3389/fphys.2020.530485] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/29/2020] [Accepted: 08/28/2020] [Indexed: 11/13/2022] Open
Abstract
Mechanical ventilation of lungs suffering from microatelectases may trigger the development of acute lung injury (ALI). Direct lung injury by bleomycin results in surfactant dysfunction and microatelectases at day 1 while tissue elastance and oxygenation remain normal. Computational simulations of alveolar micromechanics 1-day post-bleomycin predict persisting microatelectases throughout the respiratory cycle and increased alveolar strain during low positive end-expiratory pressure (PEEP) ventilation. As such, we hypothesize that mechanical ventilation in presence of microatelectases, which occur at low but not at higher PEEP, aggravates and unmasks ALI in the bleomycin injury model. Rats were randomized and challenged with bleomycin (B) or not (H = healthy). One day after bleomycin instillation the animals were ventilated for 3 h with PEEP 1 (PEEP1) or 5 cmH2O (PEEP5) and a tidal volume of 10 ml/kg bodyweight. Tissue elastance was repetitively measured after a recruitment maneuver to investigate the degree of distal airspace instability. The right lung was subjected to bronchoalveolar lavage (BAL), the left lung was fixed for design-based stereology at light- and electron microscopic level. Prior to mechanical ventilation, lung tissue elastance did not differ. During mechanical ventilation tissue elastance increased in bleomycin-injured lungs ventilated with PEEP = 1 cmH2O but remained stable in all other groups. Measurements at the conclusion of ventilation showed the largest time-dependent increase in tissue elastance after recruitment in B/PEEP1, indicating increased instability of distal airspaces. These lung mechanical findings correlated with BAL measurements including elevated BAL neutrophilic granulocytes as well as BAL protein and albumin in B/PEEP1. Moreover, the increased septal wall thickness and volume of peri-bronchiolar-vascular connective tissue in B/PEEP1 suggested aggravation of interstitial edema by ventilation in presence of microatelectases. At the electron microscopic level, the largest surface area of injured alveolar epithelial was observed in bleomycin-challenged lungs after PEEP = 1 cmH2O ventilation. After bleomycin treatment cellular markers of endoplasmic reticulum stress (p-Perk and p-EIF-2α) were positive within the septal wall and ventilation with PEEP = 1 cmH2O ventilation increased the surface area stained positively for p-EIF-2α. In conclusion, hidden microatelectases are linked with an increased pulmonary vulnerability for mechanical ventilation characterized by an aggravation of epithelial injury.
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Affiliation(s)
- Karolin Albert
- Institute of Functional and Applied Anatomy, Hannover Medical School, Hanover, Germany
| | - Jeanne-Marie Krischer
- Institute of Functional and Applied Anatomy, Hannover Medical School, Hanover, Germany
| | - Alexander Pfaffenroth
- Institute of Functional and Applied Anatomy, Hannover Medical School, Hanover, Germany
| | - Sabrina Wilde
- Fraunhofer Institute for Toxicology and Experimental Medicine, Hanover, Germany.,Biomedical Research in Endstage and Obstructive Lung Disease Hannover (BREATH), German Center for Lung Research, Hanover, Germany
| | - Elena Lopez-Rodriguez
- Institute of Functional and Applied Anatomy, Hannover Medical School, Hanover, Germany.,Biomedical Research in Endstage and Obstructive Lung Disease Hannover (BREATH), German Center for Lung Research, Hanover, Germany.,Institute for Functional Anatomy, Charité, Berlin, Germany
| | - Armin Braun
- Fraunhofer Institute for Toxicology and Experimental Medicine, Hanover, Germany.,Biomedical Research in Endstage and Obstructive Lung Disease Hannover (BREATH), German Center for Lung Research, Hanover, Germany
| | - Bradford J Smith
- Department of Bioengineering, College of Engineering, Design and Computing, University of Colorado Denver, Anschutz Medical Campus, Aurora, CO, United States
| | - Lars Knudsen
- Institute of Functional and Applied Anatomy, Hannover Medical School, Hanover, Germany.,Biomedical Research in Endstage and Obstructive Lung Disease Hannover (BREATH), German Center for Lung Research, Hanover, Germany
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14
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Das P, Curstedt T, Agarwal B, Prahaladan VM, Ramirez J, Bhandari S, Syed MA, Salomone F, Casiraghi C, Pelizzi N, Bhandari V. Small Molecule Inhibitor Adjuvant Surfactant Therapy Attenuates Ventilator- and Hyperoxia-Induced Lung Injury in Preterm Rabbits. Front Physiol 2020; 11:266. [PMID: 32327998 PMCID: PMC7160647 DOI: 10.3389/fphys.2020.00266] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/14/2019] [Accepted: 03/09/2020] [Indexed: 12/15/2022] Open
Abstract
Background Invasive mechanical ventilation (IMV) has become one of the mainstays of therapy in NICUs worldwide, as a result of which premature babies with extremely low birth weight have been able to survive. Although lifesaving, IMV can result in lung inflammation and injury. Surfactant therapy is considered a standard of care in preterm infants with immature lungs. Recently, small molecule inhibitors like siRNAs and miRNAs have been used for therapeutic purposes. Ddit3 (CHOP), Ang2 and miR34a are known to be upregulated in experimental lung injury. We wanted to test whether inhibitors for these molecules (CHOP siRNA, Ang2 siRNA, and miR34a antagomir) if used alone or with a combination with surfactant (Curosurf®) would help in reducing ventilation and hyperoxia-induced injury in an experimental lung injury model. Methods Preterm rabbits born by cesarean section were intratracheally instilled with the three small molecule inhibitors with or without Curosurf® prior to IMV and hyperoxia exposure. Prior to testing the inhibitors in rabbits, these small molecule inhibitors were transfected in mouse lung epithelial cells (MLE12 and AECII) and delivered to neonatal mouse pups intranasally as a proof of concept that surfactant (Curosurf®) could be used as an effective vehicle for administration of such drugs. Survival, pulmonary function tests, histopathology, immunostaining, quantitative PCR and western blotting were done to see the adjuvant effect of surfactant with these three small molecule inhibitors. Results Our data shows that Curosurf® can facilitate transfection of small molecules in MLE12 cells with the same and/or increased efficiency as Lipofectamine. Surfactant given alone or as an adjuvant with small molecule inhibitors increases survival, decreases IMV and hyperoxia-induced inflammation, improves pulmonary function and lung injury scores in preterm rabbit kits. Conclusion Our study shows that Curosurf® can be used successfully as an adjuvant therapy with small molecule inhibitors for CHOP/Ang2/miR34a. In this study, of the three inhibitors used, miR34a inhibitor seemed to be the most promising compound to combat IMV and hyperoxia-induced lung injury in preterm rabbits.
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Affiliation(s)
- Pragnya Das
- Department of Pediatrics, Drexel University, Philadelphia, PA, United States
| | - Tore Curstedt
- Department of Molecular Medicine and Surgery, Karolinska Institutet, Karolinska University Hospital, Stockholm, Sweden
| | | | - Varsha M Prahaladan
- Department of Pediatrics, Drexel University, Philadelphia, PA, United States
| | - John Ramirez
- Department of Pediatrics, Yale University School of Medicine, New Haven, CT, United States
| | - Shreya Bhandari
- Department of Pediatrics, Drexel University, Philadelphia, PA, United States
| | - Mansoor A Syed
- Department of Pediatrics, Yale University School of Medicine, New Haven, CT, United States
| | | | | | | | - Vineet Bhandari
- Department of Pediatrics, Drexel University, Philadelphia, PA, United States.,Department of Pediatrics, Yale University School of Medicine, New Haven, CT, United States
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15
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Bersten AD, Krupa M, Griggs K, Dixon DL. Reduced Surfactant Contributes to Increased Lung Stiffness Induced by Rapid Inspiratory Flow. Lung 2020; 198:43-52. [PMID: 31915922 DOI: 10.1007/s00408-019-00317-1] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/05/2019] [Accepted: 12/24/2019] [Indexed: 10/25/2022]
Abstract
INTRODUCTION The mechanism of fast inspiratory flow rate (VI') induced lung injury is unclear. As fast VI' increases hysteresis, a measure of surface tension at the air-liquid interface, surfactant release or function may be important. This experimental study examines the contribution of impaired surfactant release or function to dynamic-VILI. METHODS Isolated perfused lungs from male Sprague Dawley rats were randomly allocated to four groups: a long or short inspiratory time (Ti = 0.5 s; slow VI' or Ti = 0.1 s; fast VI') at PEEP of 2 or 10 cmH2O. Tidal volume was constant (7 ml/kg), with f = 60 breath/min. Forced impedance mechanics (tissue elastance (Htis), tissue resistance (Gtis) and airway resistance (Raw) were measured at 30, 60 and 90 min following which the lung was lavaged for surfactant phospholipids (PL) and disaturated PL (DSP). RESULTS Fast VI' resulted in a stiffer lung. Concurrently, PL and DSP were decreased in both tubular myelin rich and poor fractions. Phospholipid decreases were similar with PEEP. In a subsequent cohort, laser confocal microscopy-based assessment demonstrated increased cellular injury with increased VI' at both 30 and 90 min ventilation. CONCLUSION Rapid VI' may contribute to ventilator induced lung injury (VILI) through reduced surfactant release and/or more rapid reuptake despite unchanged tidal stretch.
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Affiliation(s)
- Andrew D Bersten
- Intensive and Critical Care Unit, Flinders Medical Centre, Adelaide, SA, Australia.,Department of Critical Care Medicine, College of Medicine and Public Health, Flinders University, Adelaide, SA, 5001, Australia
| | - Malgorzata Krupa
- Department of Critical Care Medicine, College of Medicine and Public Health, Flinders University, Adelaide, SA, 5001, Australia
| | - Kim Griggs
- Department of Critical Care Medicine, College of Medicine and Public Health, Flinders University, Adelaide, SA, 5001, Australia
| | - Dani-Louise Dixon
- Intensive and Critical Care Unit, Flinders Medical Centre, Adelaide, SA, Australia. .,Department of Critical Care Medicine, College of Medicine and Public Health, Flinders University, Adelaide, SA, 5001, Australia.
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16
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Szabari MV, Takahashi K, Feng Y, Locascio JJ, Chao W, Carter EA, Vidal Melo MF, Musch G. Relation between Respiratory Mechanics, Inflammation, and Survival in Experimental Mechanical Ventilation. Am J Respir Cell Mol Biol 2019; 60:179-188. [PMID: 30199644 DOI: 10.1165/rcmb.2018-0100oc] [Citation(s) in RCA: 18] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022] Open
Abstract
Low-tidal volume (Vt) ventilation might protect healthy lungs from volutrauma but lead to inflammation resulting from other mechanisms, namely alveolar derecruitment and the ensuing alveolar collapse and tidal reexpansion. We hypothesized that the different mechanisms of low- and high-volume injury would be reflected in different mechanical properties being associated with development of pulmonary inflammation and mortality: an increase of hysteresis, reflecting progressive alveolar derecruitment, at low Vt; an increase of elastance, as a result of overdistension, at higher Vt. Mice were allocated to "protective" (6 ml/kg) or "injurious" (15-20 ml/kg) Vt groups and ventilated for 16 hours or until death. We measured elastance and hysteresis; pulmonary IL-6, IL-1β, and MIP-2 (macrophage inflammatory protein 2); wet-to-dry ratio; and blood gases. Survival was greater in the protective group (60%) than in the injurious group (25%). Nonsurvivors showed increased pulmonary cytokines, particularly in the injurious group, with the increase of elastance reflecting IL-6 concentration. Survivors instead showed only modest increases of cytokines, independent of Vt and unrelated to the increase of elastance. No single lung strain threshold could discriminate survivors from nonsurvivors. Hysteresis increased faster in the protective group, but, contrary to our hypothesis, its change was inversely related to the concentration of cytokines. In this model, significant mortality associated with pulmonary inflammation occurred even for strain values as low as about 0.8. Low Vt improved survival. The accompanying increase of hysteresis was not associated with greater inflammation.
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Affiliation(s)
- Margit V Szabari
- 1 Department of Anesthesia, Critical Care and Pain Medicine.,2 Department of Medicine
| | | | - Yan Feng
- 1 Department of Anesthesia, Critical Care and Pain Medicine.,4 Department of Anesthesiology, University of Maryland School of Medicine, Baltimore, Maryland; and
| | | | - Wei Chao
- 1 Department of Anesthesia, Critical Care and Pain Medicine.,4 Department of Anesthesiology, University of Maryland School of Medicine, Baltimore, Maryland; and
| | - Edward A Carter
- 6 Department of Pediatrics, Massachusetts General Hospital and Harvard Medical School, Boston, Massachusetts
| | | | - Guido Musch
- 1 Department of Anesthesia, Critical Care and Pain Medicine.,7 Department of Anesthesiology, Washington University in St. Louis, St. Louis, Missouri
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17
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Endoplasmic reticulum stress is involved in ventilator-induced lung injury in mice via the IRE1α-TRAF2-NF-κB pathway. Int Immunopharmacol 2019; 78:106069. [PMID: 31841755 DOI: 10.1016/j.intimp.2019.106069] [Citation(s) in RCA: 17] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/01/2019] [Revised: 11/19/2019] [Accepted: 11/20/2019] [Indexed: 12/12/2022]
Abstract
Inflammation plays a criticalrole in the development of ventilator-induced lung injury (VILI). Endoplasmic reticulum (ER) stress is associated with a variety of diseases through the modulation of inflammatory responses. However, little is known about how ER stress is implicated in VILI. In this study, murine mechanical ventilation models were constructed. Total protein and inflammatory cytokines were measured in bronchoalveolar lavage fluid (BALF),and lung tissue injurywasassessedby histology. Our data revealed that mice subjected to high tidal ventilation (TV) for 4 h showed more severe pulmonary edema and inflammation than those of mice with spontaneous breathing and low TV-treatment. In addition, the high TV-treated animals upregulated the ER stress markers GRP78, CHOP, p-IRE1α, TRAF2, and p-NF-κB expression at both the mRNA and protein levels in lung tissue. Administration of thapsigargin exacerbated the histological changes, inflammation and expression of GRP78 and CHOP after high TV, but treatment with ER stress and IRE1α kinase inhibitors attenuated the pathological damage and downregulated the high expression of GRP78, CHOP, p-IRE1α, TRAF2, and p-NF-κB, suggesting that ER stress is involved in VILI though the IRE1α/TRAF2/NF-κB signaling pathway in mice.
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18
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Viola H, Chang J, Grunwell JR, Hecker L, Tirouvanziam R, Grotberg JB, Takayama S. Microphysiological systems modeling acute respiratory distress syndrome that capture mechanical force-induced injury-inflammation-repair. APL Bioeng 2019; 3:041503. [PMID: 31768486 PMCID: PMC6874511 DOI: 10.1063/1.5111549] [Citation(s) in RCA: 18] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/27/2019] [Accepted: 11/08/2019] [Indexed: 12/14/2022] Open
Abstract
Complex in vitro models of the tissue microenvironment, termed microphysiological systems, have enormous potential to transform the process of discovering drugs and disease mechanisms. Such a paradigm shift is urgently needed in acute respiratory distress syndrome (ARDS), an acute lung condition with no successful therapies and a 40% mortality rate. Here, we consider how microphysiological systems could improve understanding of biological mechanisms driving ARDS and ultimately improve the success of therapies in clinical trials. We first discuss how microphysiological systems could explain the biological mechanisms underlying the segregation of ARDS patients into two clinically distinct phenotypes. Then, we contend that ARDS-mimetic microphysiological systems should recapitulate three critical aspects of the distal airway microenvironment, namely, mechanical force, inflammation, and fibrosis, and we review models that incorporate each of these aspects. Finally, we recognize the substantial challenges associated with combining inflammation, fibrosis, and/or mechanical force in microphysiological systems. Nevertheless, complex in vitro models are a novel paradigm for studying ARDS, and they could ultimately improve patient care.
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Affiliation(s)
| | - Jonathan Chang
- Wallace H. Coulter Department of Biomedical Engineering, Georgia Institute of Technology and Emory School of Medicine, Atlanta, Georgia 30332, USA
| | - Jocelyn R. Grunwell
- Department of Pediatrics, Division of Critical Care Medicine, Children's Healthcare of Atlanta at Egleston, Emory University School of Medicine, Atlanta, Georgia 30322, USA
| | - Louise Hecker
- Division of Pulmonary, Allergy and Critical Care and Sleep Medicine, University of Arizona, Tucson, Arizona 85724, USA and Southern Arizona Veterans Affairs Health Care System, Tucson, Arizona 85723, USA
| | - Rabindra Tirouvanziam
- Department of Pediatrics, Emory University School of Medicine, Atlanta, Georgia 30322, USA and Center for CF and Airways Disease Research, Children's Healthcare of Atlanta, Atlanta, Georgia 30322, USA
| | - James B. Grotberg
- Department of Biomedical Engineering, University of Michigan, Ann Arbor, Michigan 48109, USA
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19
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Comber EM, Palchesko RN, Ng WH, Ren X, Cook KE. De novo lung biofabrication: clinical need, construction methods, and design strategy. Transl Res 2019; 211:1-18. [PMID: 31103468 DOI: 10.1016/j.trsl.2019.04.008] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/01/2019] [Revised: 04/10/2019] [Accepted: 04/25/2019] [Indexed: 01/22/2023]
Abstract
Chronic lung disease is the 4th leading cause of death in the United States. Due to a shortage of donor lungs, alternative approaches to support failing, native lungs have been attempted, including mechanical ventilation and various forms of artificial lungs. However, each of these support methods causes significant complications when used for longer than a few days and are thus not capable of long-term support. For artificial lungs, complications arise due to interactions between the artificial materials of the device and the blood of the recipient. A potential new approach is the fabrication of lungs from biological materials, such that the gas exchange membranes provide a more biomimetic blood-contacting interface. Recent advancements with three-dimensional, soft-tissue biofabrication methods and the engineering of thin, basement membranes demonstrate the potential of fabricating a lung scaffold from extracellular matrix materials. This scaffold could then be seeded with endothelial and epithelial cells, matured within a bioreactor, and transplanted. In theory, this fully biological lung could provide improved, long-term biocompatibility relative to artificial lungs, but significant work is needed to perfect the organ design and construction methods. Like artificial lungs, biofabricated lungs do not need to follow the shape and structure of a native lung, allowing for simpler manufacture. However, various functional requirements must still be met, including stable, efficient gas exchange for a period of years. Design decisions depend on the disease state, how the organ is implanted, and the latest biofabrication methods available in a rapidly evolving field.
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Affiliation(s)
- Erica M Comber
- Department of Biomedical Engineering, Carnegie Mellon University, Pittsburgh, Pennsylvania.
| | - Rachelle N Palchesko
- Department of Biomedical Engineering, Carnegie Mellon University, Pittsburgh, Pennsylvania
| | - Wai Hoe Ng
- Department of Biomedical Engineering, Carnegie Mellon University, Pittsburgh, Pennsylvania
| | - Xi Ren
- Department of Biomedical Engineering, Carnegie Mellon University, Pittsburgh, Pennsylvania
| | - Keith E Cook
- Department of Biomedical Engineering, Carnegie Mellon University, Pittsburgh, Pennsylvania
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20
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Albert RK, Smith B, Perlman CE, Schwartz DA. Is Progression of Pulmonary Fibrosis due to Ventilation-induced Lung Injury? Am J Respir Crit Care Med 2019; 200:140-151. [PMID: 31022350 PMCID: PMC6635778 DOI: 10.1164/rccm.201903-0497pp] [Citation(s) in RCA: 45] [Impact Index Per Article: 9.0] [Reference Citation Analysis] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/01/2019] [Accepted: 04/22/2019] [Indexed: 02/06/2023] Open
Affiliation(s)
| | - Bradford Smith
- Department of Bioengineering, University of Colorado, Aurora, Colorado; and
| | - Carrie E. Perlman
- Department of Biomedical Engineering, Stevens Institute of Technology, Hoboken, New Jersey
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21
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Surfactant dysfunction and alveolar collapse are linked with fibrotic septal wall remodeling in the TGF-β1-induced mouse model of pulmonary fibrosis. J Transl Med 2019; 99:830-852. [PMID: 30700849 DOI: 10.1038/s41374-019-0189-x] [Citation(s) in RCA: 28] [Impact Index Per Article: 5.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/06/2018] [Revised: 11/20/2018] [Accepted: 12/17/2018] [Indexed: 11/08/2022] Open
Abstract
In human idiopathic pulmonary fibrosis (IPF), collapse of distal airspaces occurs in areas of the lung not (yet) remodeled. Mice lungs overexpressing transforming growth factor-β1 (TGF-β1) recapitulate this abnormality: surfactant dysfunction results in alveolar collapse preceding fibrosis and loss of alveolar epithelial type II (AE2) cells' apical membrane surface area. Here we examined whether surfactant dysfunction-related alveolar collapse due to TGF-β1 overexpression is linked to septal wall remodeling and AE2 cell abnormalities. Three and 6 days after gene transfer of TGF-β1, mice received either intratracheal surfactant (Surf-groups: Curosurf®, 100 mg/kg bodyweight) or 0.9% NaCl (Saline-groups). On days 7 (D7) and 14 (D14), lung mechanics were assessed followed by design-based stereology at light and electron microscopic level to quantify structures. Compared with Saline, Surf showed significantly improved tissue elastance, increased numbers of open alveoli, as well as reduced alveolar size heterogeneity on D7. Deterioration in lung mechanics was highly correlated to the loss of open alveoli. On D14, lung mechanics, number of open alveoli, and alveolar size heterogeneity remained significantly improved in the Surf-group. Volumes of extracellular matrix and collagen fibrils in septal walls were significantly reduced, whereas the apical membrane surface area of AE2 cells was increased in Surf compared with Saline. In remodeled tissue with collapsed alveoli, three-dimensional reconstruction of AE2 cells based on scanning electron microscopy array tomography revealed that AE2 cells were trapped without contact to airspaces in the TGF-β1 mouse model. Similar observations were made in human IPF. Based on correlation analyses, the number of open alveoli and of alveolar size heterogeneity were highly linked with the loss of apical membrane surface area of AE2 cells and deposition of collagen fibrils in septal walls on D14. In conclusion, surfactant replacement therapy stabilizes alveoli and prevents extracellular matrix deposition in septal walls in the TGF-β1 model.
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Knudsen L, Ochs M. The micromechanics of lung alveoli: structure and function of surfactant and tissue components. Histochem Cell Biol 2018; 150:661-676. [PMID: 30390118 PMCID: PMC6267411 DOI: 10.1007/s00418-018-1747-9] [Citation(s) in RCA: 179] [Impact Index Per Article: 29.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 10/19/2018] [Indexed: 12/14/2022]
Abstract
The mammalian lung´s structural design is optimized to serve its main function: gas exchange. It takes place in the alveolar region (parenchyma) where air and blood are brought in close proximity over a large surface. Air reaches the alveolar lumen via a conducting airway tree. Blood flows in a capillary network embedded in inter-alveolar septa. The barrier between air and blood consists of a continuous alveolar epithelium (a mosaic of type I and type II alveolar epithelial cells), a continuous capillary endothelium and the connective tissue layer in-between. By virtue of its respiratory movements, the lung has to withstand mechanical challenges throughout life. Alveoli must be protected from over-distension as well as from collapse by inherent stabilizing factors. The mechanical stability of the parenchyma is ensured by two components: a connective tissue fiber network and the surfactant system. The connective tissue fibers form a continuous tensegrity (tension + integrity) backbone consisting of axial, peripheral and septal fibers. Surfactant (surface active agent) is the secretory product of type II alveolar epithelial cells and covers the alveolar epithelium as a biophysically active thin and continuous film. Here, we briefly review the structural components relevant for gas exchange. Then we describe our current understanding of how these components function under normal conditions and how lung injury results in dysfunction of alveolar micromechanics finally leading to lung fibrosis.
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Affiliation(s)
- Lars Knudsen
- Institute of Functional and Applied Anatomy, Hannover Medical School, Carl-Neuberg-Str. 1, 30625, Hannover, Germany.,Biomedical Research in Endstage and Obstructive Lung Disease Hannover (BREATH), Member of the German Center for Lung Research (DZL), Hannover, Germany.,REBIRTH Cluster of Excellence, Hannover, Germany
| | - Matthias Ochs
- Institute of Functional and Applied Anatomy, Hannover Medical School, Carl-Neuberg-Str. 1, 30625, Hannover, Germany. .,Biomedical Research in Endstage and Obstructive Lung Disease Hannover (BREATH), Member of the German Center for Lung Research (DZL), Hannover, Germany. .,REBIRTH Cluster of Excellence, Hannover, Germany.
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Zhang S, Dai H, Zhu L, Lin F, Hu Z, Jing R, Zhang W, Zhao C, Hong X, Zhong JH, Pan L. Microvesicles packaging IL-1β and TNF-α enhance lung inflammatory response to mechanical ventilation in part by induction of cofilin signaling. Int Immunopharmacol 2018; 63:74-83. [DOI: 10.1016/j.intimp.2018.07.034] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/03/2018] [Revised: 07/13/2018] [Accepted: 07/26/2018] [Indexed: 12/18/2022]
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Dolinay T, Aonbangkhen C, Zacharias W, Cantu E, Pogoriler J, Stablow A, Lawrence GG, Suzuki Y, Chenoweth DM, Morrisey E, Christie JD, Beers MF, Margulies SS. Protein kinase R-like endoplasmatic reticulum kinase is a mediator of stretch in ventilator-induced lung injury. Respir Res 2018; 19:157. [PMID: 30134920 PMCID: PMC6106739 DOI: 10.1186/s12931-018-0856-2] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/06/2018] [Accepted: 08/06/2018] [Indexed: 12/22/2022] Open
Abstract
Background Acute respiratory distress syndrome (ARDS) is a severe form of lung injury characterized by damage to the epithelial barrier with subsequent pulmonary edema and hypoxic respiratory failure. ARDS is a significant medical problem in intensive care units with associated high care costs. There are many potential causes of ARDS; however, alveolar injury associated with mechanical ventilation, termed ventilator-induced lung injury (VILI), remains a well-recognized contributor. It is thus critical to understand the mechanism of VILI. Based on our published preliminary data, we hypothesized that the endoplasmic reticulum (ER) stress response molecule Protein Kinase R-like Endoplasmic Reticulum Kinase (PERK) plays a role in transmitting mechanosensory signals the alveolar epithelium. Methods ER stress signal responses to mechanical stretch were studied in ex-vivo ventilated pig lungs. To explore the effect of PERK inhibition on VILI, we ventilated live rats and compared lung injury parameters to non-ventilated controls. The effect of stretch-induced epithelial ER Ca2+ signaling on PERK was studied in stretched alveolar epithelial monolayers. To confirm the activation of PERK in human disease, ER stress signaling was compared between ARDS and non-ARDS lungs. Results Our studies revealed increased PERK-specific ER stress signaling in response to overstretch. PERK inhibition resulted in dose-dependent improvement of alveolar inflammation and permeability. Our data indicate that stretch-induced epithelial ER Ca2+ release is an activator of PERK. Experiments with human lung tissue confirmed PERK activation by ARDS. Conclusion Our study provides evidences that PERK is a mediator stretch signals in the alveolar epithelium.
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Affiliation(s)
- Tamás Dolinay
- Department of Medicine, Division of Pulmonary, Allergy and Critical Care Medicine, University of Pennsylvania, 3400 Spruce St, Philadelphia, PA, 19104, USA.,Department of Medicine, Division of Pulmonary and Critical Care Medicine, University of California Los Angeles, 10833 Le Conte Ave, Los Angeles, CA, 90095, USA
| | - Chanat Aonbangkhen
- Department of Chemistry University of Pennsylvania, 231 S 34th St, Philadelphia, PA, 19104, USA
| | - William Zacharias
- Department of Medicine, Division of Pulmonary, Allergy and Critical Care Medicine, University of Pennsylvania, 3400 Spruce St, Philadelphia, PA, 19104, USA
| | - Edward Cantu
- Department of Surgery, University of Pennsylvania, 3400 Spruce St, Philadelphia, PA, 19104, USA
| | - Jennifer Pogoriler
- Department of Pathology, Children's Hospital of Philadelphia, 3400 S 34th St, Philadelphia, PA, 19104, USA
| | - Alec Stablow
- Department of Bioengineering, University of Pennsylvania, 210 South 33rd St, Suite 240 Skirkanich Hall Philadelphia, Philadelphia, PA, 19104, USA
| | - Gladys G Lawrence
- Department of Bioengineering, University of Pennsylvania, 210 South 33rd St, Suite 240 Skirkanich Hall Philadelphia, Philadelphia, PA, 19104, USA
| | - Yoshikazu Suzuki
- Department of Surgery, University of Pennsylvania, 3400 Spruce St, Philadelphia, PA, 19104, USA
| | - David M Chenoweth
- Department of Chemistry University of Pennsylvania, 231 S 34th St, Philadelphia, PA, 19104, USA
| | - Edward Morrisey
- Department of Medicine, Division of Cardiovascular Medicine, University of Pennsylvania, 3400 Spruce St, Philadelphia, PA, 19104, USA
| | - Jason D Christie
- Department of Medicine, Division of Pulmonary, Allergy and Critical Care Medicine, University of Pennsylvania, 3400 Spruce St, Philadelphia, PA, 19104, USA
| | - Michael F Beers
- Department of Medicine, Division of Pulmonary, Allergy and Critical Care Medicine, University of Pennsylvania, 3400 Spruce St, Philadelphia, PA, 19104, USA
| | - Susan S Margulies
- Department of Bioengineering, University of Pennsylvania, 210 South 33rd St, Suite 240 Skirkanich Hall Philadelphia, Philadelphia, PA, 19104, USA. .,Wallace H. Coulter Department of Biomedical Engineering Georgia Institute of Technology and Emory University, University School of Medicine, U.A. Whitaker Building, 313 Ferst Drive, Suite 2116, Atlanta, GA, 30332-0535, USA.
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Inflammation and Monocyte Recruitment due to Aging and Mechanical Stretch in Alveolar Epithelium are Inhibited by the Molecular Chaperone 4-phenylbutyrate. Cell Mol Bioeng 2018; 11:495-508. [PMID: 30581495 DOI: 10.1007/s12195-018-0537-8] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023] Open
Abstract
Introduction Ventilator-Induced lung injury (VILI) is a form of acute lung injury that is initiated or exacerbated by mechanical ventilation. The aging lung is also more susceptible to injury. Harmful mechanical stretch of the alveolar epithelium is a recognized mechanism of VILI, yet little is known about how mechanical stretch affects aged epithelial cells. Disruption to Endoplasmic Reticulum (ER) homeostasis results in a condition known as ER stress that leads to disruption of cellular homeostasis, apoptosis, and inflammation. ER stress is increased with aging and other pathological stimuli. We hypothesized that age and mechanical stretch increase alveolar epithelial cells' proinflammatory responses that are mediated by ER stress. Furthermore, we believed that inhibition of this upstream mechanism with 4PBA, an ER stress reducer, alleviates subsequent inflammation and monocyte recruitment. Methods Type II alveolar epithelial cells (ATII) were harvested from C57Bl6/J mice 2 months (young) and 20 months (old) of age. The cells were cyclically stretched at 15% change in surface area for up to 24 hours. Prior to stretch, groups were administered 4PBA or vehicle as a control. Results Mechanical stretch and age upregulated ER stress and proinflammatory MCP-1/CCL2 and MIP-1β/CCL4 chemokine expression in ATIIs. Age-matched and mismatched monocyte recruitment by ATII conditioned media was also quantified. Conclusions Age increases susceptibility to stretch-induced ER stress and downstream inflammatory gene expression in a primary ATII epithelial cell model. Administration of 4PBA attenuated the increased ER stress and proinflammatory responses from stretch and/or age and significantly reduced monocyte migration to ATII conditioned media.
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Yi L, Pimentel H, Bray NL, Pachter L. Gene-level differential analysis at transcript-level resolution. Genome Biol 2018; 19:53. [PMID: 29650040 PMCID: PMC5896116 DOI: 10.1186/s13059-018-1419-z] [Citation(s) in RCA: 76] [Impact Index Per Article: 12.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/05/2017] [Accepted: 03/08/2018] [Indexed: 11/23/2022] Open
Abstract
Compared to RNA-sequencing transcript differential analysis, gene-level differential expression analysis is more robust and experimentally actionable. However, the use of gene counts for statistical analysis can mask transcript-level dynamics. We demonstrate that ‘analysis first, aggregation second,’ where the p values derived from transcript analysis are aggregated to obtain gene-level results, increase sensitivity and accuracy. The method we propose can also be applied to transcript compatibility counts obtained from pseudoalignment of reads, which circumvents the need for quantification and is fast, accurate, and model-free. The method generalizes to various levels of biology and we showcase an application to gene ontologies.
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Affiliation(s)
- Lynn Yi
- UCLA-Caltech Medical Science Training Program, Los Angeles, CA, USA.,Division of Biology and Biological Engineering, Caltech, Pasadena, CA, USA
| | - Harold Pimentel
- Department of Genetics, Stanford University, Palo Alto, CA, USA
| | | | - Lior Pachter
- Division of Biology and Biological Engineering, Caltech, Pasadena, CA, USA. .,Department of Computing and Mathematical Sciences, Caltech, Pasadena, CA, USA.
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Lecuona E, Sznajder JI. Stretching to Understand How Proteostasis and the Unfolded Protein Response Regulate Lung Injury. Am J Respir Cell Mol Biol 2018; 57:143-144. [PMID: 28762764 DOI: 10.1165/rcmb.2017-0170ed] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022] Open
Affiliation(s)
- Emilia Lecuona
- 1 Pulmonary and Critical Care Medicine Northwestern University Chicago, Illinois
| | - Jacob I Sznajder
- 1 Pulmonary and Critical Care Medicine Northwestern University Chicago, Illinois
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