Revisiting Cell Death Responses in Fibrotic Lung Disease: Crosstalk between Structured and Non-Structured Cells

Fibrosis is a life-threatening disorder caused by excessive formation of connective tissue that can affect several critical organs. Innate immune cells are involved in the development of various disorders, including lung fibrosis. To date, several hematopoietic cell types have been implicated in fibrosis, including pro-fibrotic monocytes like fibrocytes and segregated-nucleus-containing atypical monocytes (SatMs), but the precise cellular and molecular mechanisms underlying its development remain unclear. Repetitive injury and subsequent cell death response are triggering events for lung fibrosis development. Crosstalk between lung structured and non-structured cells is known to regulate the key molecular event. We recently reported that RNA-binding motif protein 7 (RBM7) expression is highly upregulated in the fibrotic lung and plays fundamental roles in fibrosis development. RBM7 regulates nuclear degradation of NEAT1 non-coding RNA, resulting in sustained apoptosis in the lung epithelium and fibrosis. Apoptotic epithelial cells produce CXCL12, which leads to the recruitment of pro-fibrotic monocytes. Apoptosis is also the main source of autoantigens. Recent studies have revealed important functions for natural autoantibodies that react with specific sets of self-antigens and are unique to individual diseases. Here, we review recent insights into lung fibrosis development in association with crosstalk between structured cells like lung epithelial cells and non-structured cells like migrating immune cells, and discuss their relevance to acquired immunity through natural autoantibody production.

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F-Box Protein FBXW17-Mediated Proteasomal Degradation of Protein Methyltransferase PRMT6 Exaggerates CSE-Induced Lung Epithelial Inflammation and Apoptosis

Frontiers in Cell and Developmental Biology ◽

10.3389/fcell.2021.599020 ◽

2021 ◽

Vol 9 ◽

Author(s):

Tiao Li ◽

Xue He ◽

Lijuan Luo ◽

Huihui Zeng ◽

Siying Ren ◽

...

Keyword(s):

Cell Death ◽

Epithelial Cells ◽

Airway Inflammation ◽

Cigarette Smoke ◽

Cell Apoptosis ◽

Molecular Mechanisms ◽

Lung Epithelial Cells ◽

Chronic Obstructive ◽

Structural Cell ◽

Lung Epithelial

Chronic obstructive pulmonary disease (COPD) is a chronic debilitating lung disease, characterized by progressive airway inflammation and lung structural cell death. Cigarette smoke is considered the most common risk factor of COPD pathogenesis. Understanding the molecular mechanisms of persistent inflammation and epithelial apoptosis induced by cigarette smoke would be extremely beneficial for improving the treatment and prevention of COPD. A histone methyl modifier, protein arginine N-methyltransferase 6 (PRMT6), is reported to alleviate cigarette smoke extract (CSE)-induced emphysema through inhibiting inflammation and cell apoptosis. However, few studies have focused on the modulation of PRMT6 in regulating inflammation and cell apoptosis. In this study, we showed that protein expression of PRMT6 was aberrantly decreased in the lung tissue of COPD patients and CSE-treated epithelial cells. FBXW17, a member of the Skp1-Cullin-F-box (SCF) family of E3 ubiquitin ligases, selectively bound to PRMT6 in nuclei to modulate its elimination in the proteasome system. Proteasome inhibitor or silencing of FBXW17 abrogated CSE-induced PRMT6 protein degradation. Furthermore, negative alteration of FBXW17/PRMT6 signaling lessened the proapoptotic and proinflammatory effects of CSE in lung epithelial cells. Our study, therefore, provides a potential therapeutic target against the airway inflammation and cell death in CS-induced COPD.

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3D printed lung on a chip device with a stretchable nanofibrous membrane for modeling ventilator induced lung injury

10.1101/2021.07.02.450873 ◽

2021 ◽

Author(s):

Sinem Tas ◽

Emil Rehnberg ◽

Deniz A. Bölükbaş ◽

Jason P. Beech ◽

Liora Nasi Kazado ◽

...

Keyword(s):

Cell Death ◽

Epithelial Cells ◽

Lung Injury ◽

Mechanical Stretch ◽

Cell Types ◽

Lung Epithelial Cells ◽

Nanofibrous Membrane ◽

Ventilator Induced Lung Injury ◽

Lung Epithelial ◽

3D Printed

Mechanical ventilation is often required in patients with pulmonary disease to maintain adequate gas exchange. Despite improved knowledge regarding the risks of over ventilating the lung, ventilator induced lung injury (VILI) remains a major clinical problem due to inhomogeneities within the diseased lung itself as well as the need to increase pressure or volume of oxygen to the lung as a life-saving measure. VILI is characterized by increased physical forces exerted within the lung, which results in cell death, inflammation and long-term fibrotic remodeling. Animal models can be used to study VILI, but it is challenging to distinguish the contributions of individual cell types in such a setup. In vitro models, which allow for controlled stretching of specific lung cell types have emerged as a potential option, but these models and the membranes used in them are unable to recapitulate some key features of the lung such as the 3D nanofibrous structure of the alveolar basement membrane while also allowing for cells to be cultured at an air liquid interface (ALI) and undergo increased mechanical stretch that mimics VILI. Here we develop a lung on a chip device with a nanofibrous synthetic membrane to provide ALI conditions and controllable stretching, including injurious stretching mimicking VILI. The lung on a chip device consists of a thin (i.e. ~20 μm) stretchable poly(caprolactone) (PCL) nanofibrous membrane placed between two channels fabricated in polydimethylsiloxane (PDMS) using 3D printed molds. We demonstrate that this lung on a chip device can be used to induce mechanotrauma in lung epithelial cells due to cyclic pathophysiologic stretch (~25%) that mimics clinical VILI. Pathophysiologic stretch induces cell injury and subsequently cell death, which results in loss of the epithelial monolayer, a feature mimicking the early stages of VILI. We also validate the potential of our lung on a chip device to be used to explore cellular pathways known to be altered with mechanical stretch and show that pathophysiologic stretch of lung epithelial cells causes nuclear translocation of the mechanotransducers YAP/TAZ. In conclusion, we show that a breathable lung on a chip device with a nanofibrous membrane can be easily fabricated using 3D printing of the lung on a chip molds and that this model can be used to explore pathomechanisms in mechanically induced lung injury.

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SFPQ Rescues F508del-CFTR Expression and Function in Cystic Fibrosis Bronchial Epithelial Cells

10.21203/rs.3.rs-429698/v1 ◽

2021 ◽

Author(s):

Parameet Kumar ◽

Dharmendra Kumar Soni ◽

Chaitali Sen ◽

Mads B Larsen ◽

Krystyna Mazan-Mamczarz ◽

...

Keyword(s):

Cystic Fibrosis ◽

Epithelial Cells ◽

Molecular Mechanisms ◽

Rna Binding ◽

Regulation Of Gene Expression ◽

Lung Epithelial Cells ◽

Regulation Of Expression ◽

Trafficking Defects ◽

And Function

Abstract Cystic Fibrosis (CF) occurs as a result of mutations in the cystic fibrosis transmembrane conductance regulator (CFTR) gene, which lead to misfolding, trafficking defects, and impaired function of the CFTR protein. Splicing factor proline/glutamine-rich (SFPQ) is a multifunctional nuclear RNA-binding protein (RBP) implicated in the regulation of gene expression pathways and intracellular trafficking. Here, we investigated the role of SFPQ in the regulation of the expression and function of F508del-CFTR in CF lung epithelial cells. We find that the expression of SFPQ is reduced in F508del-CFTR CF epithelial cells compared to WT-CFTR control cells. Interestingly, the overexpression of SFPQ in CF cells increases the expression as well as rescues the function of F508del-CFTR. Further, comprehensive transcriptome analyses indicate that SFPQ plays a key role in activating the mutant F508del-CFTR by modulating several cellular signaling pathways. This is the first report on the role of SFPQ in the regulation of expression and function of F508del-CFTR in CF lung disease. Our findings provide new insights into SFPQ-mediated molecular mechanisms and point to possible novel epigenetic therapeutic targets for CF and related pulmonary diseases.

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Interaction of caveolin-1 with ATG12-ATG5 system suppresses autophagy in lung epithelial cells

AJP Lung Cellular and Molecular Physiology ◽

10.1152/ajplung.00268.2013 ◽

2014 ◽

Vol 306 (11) ◽

pp. L1016-L1025 ◽

Cited By ~ 41

Author(s):

Zhi-Hua Chen ◽

Jiao-Fei Cao ◽

Jie-Sen Zhou ◽

Hui Liu ◽

Luan-Qing Che ◽

...

Keyword(s):

Epithelial Cells ◽

Molecular Mechanisms ◽

Lung Epithelial Cells ◽

Major Constituent ◽

Binding Motif ◽

Conjugation System ◽

Autophagosome Formation ◽

Caveolin 1 ◽

Lung Epithelial ◽

Biochemical Analyses

Autophagy plays a pivotal role in cellular homeostasis and adaptation to adverse environments, although the regulation of this process remains incompletely understood. We have recently observed that caveolin-1 (Cav-1), a major constituent of lipid rafts on plasma membrane, can regulate autophagy in cigarette smoking-induced injury of lung epithelium, although the underlying molecular mechanisms remain incompletely understood. In the present study we found that Cav-1 interacted with and regulated the expression of ATG12-ATG5, an ubiquitin-like conjugation system crucial for autophagosome formation, in lung epithelial Beas-2B cells. Deletion of Cav-1 increased basal and starvation-induced levels of ATG12-ATG5 and autophagy. Biochemical analyses revealed that Cav-1 interacted with ATG5, ATG12, and their active complex ATG12-ATG5. Overexpression of ATG5 or ATG12 increased their interactions with Cav-1, the formation of ATG12-ATG5 conjugate, and the subsequent basal levels of autophagy but resulted in decreased interactions between Cav-1 and another molecule. Knockdown of ATG12 enhanced the ATG5-Cav-1 interaction. Mutation of the Cav-1 binding motif on ATG12 disrupted their interaction and further augmented autophagy. Cav-1 also regulated the expression of ATG16L, another autophagy protein associating with the ATG12-ATG5 conjugate during autophagosome formation. Altogether these studies clearly demonstrate that Cav-1 competitively interacts with the ATG12-ATG5 system to suppress the formation and function of the latter in lung epithelial cells, thereby providing new insights into the molecular mechanisms by which Cav-1 regulates autophagy and suggesting the important function of Cav-1 in certain lung diseases via regulation of autophagy homeostasis.

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Differential Lysotracker Uptake Defines Two Populations of Distal Epithelial Cells in Idiopathic Pulmonary Fibrosis

10.20944/preprints202112.0033.v1 ◽

2021 ◽

Author(s):

Roxana Maria Wasnick ◽

Irina Shalashova ◽

Jochen Wilhelm ◽

Ali Khadim ◽

Nicolai Schmidt ◽

...

Keyword(s):

Flow Cytometry ◽

Epithelial Cells ◽

Lung Fibrosis ◽

Cell Types ◽

Transcriptomic Analysis ◽

Lung Epithelial Cells ◽

Unknown Etiology ◽

Alveolar Epithelial ◽

Cellular Marker ◽

Two Populations

Idiopathic lung fibrosis (IPF) is a progressive and fatal degenerative lung disease of unknown etiology. Although in its final stages it implicates in a reactive manner all lung cell types, the initial damage involves the alveolar epithelial compartment, in particular the alveolar epithelial type 2 cells (AEC2s). AEC2s serve dual progenitor and surfactant secreting functions, both of which are deeply impacted in IPF. Thus, we hypothesize that the size of the surfactant processing compartment, as measured by Lysotracker incorporation, allows the identification of different epithelial states in the IPF lung. Flow cytometry analysis of epithelial Lysotracker incorporation delineates two populations (Lysohigh and Lysolow) of AEC2s which behave in a compensatory manner during bleomycin injury and in the donor/IPF lung. Employing flow cytometry and transcriptomic analysis of cells isolated from donor and IPF lungs, we demonstrate that the Lysohigh population expresses all classical AEC2 markers and is drastically diminished in IPF. The Lysolow population, which is increased in proportion in IPF, co-expresses AEC2s and basal cell markers resembling the phenotype of the previously identified intermediate AEC2 population in the IPF lung. In that regard, we provide an in-depth flow-cytometry characterization of Lysotracker uptake, HTII-280, proSP-C, mature SP-B, NGFR, KRT5 and CD24 expression in human lung epithelial cells. Combining functional analysis with extra- and intra- cellular marker expression and transcriptomic analysis, we advance the current understanding of epithelial cell behavior and fate in lung fibrosis.

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SARS-CoV-2 activates lung epithelia cell proinflammatory signaling and leads to immune dysregulation in COVID-19 patients by single-cell sequencing

10.1101/2020.05.08.20096024 ◽

2020 ◽

Cited By ~ 1

Author(s):

Huarong Chen ◽

Weixin Liu ◽

Dabin Liu ◽

Liuyang Zhao ◽

Jun Yu

Keyword(s):

Immune Response ◽

Epithelial Cells ◽

Nk Cells ◽

Single Cell ◽

Immune Cells ◽

Cell Types ◽

Lung Epithelial Cells ◽

Healthy Controls ◽

Inflammatory Signaling ◽

Lung Epithelial

Objective: The outbreak of Coronavirus disease 2019 (COVID-19) caused by SARS-CoV-2 infection has become a global health emergency. We aim to decipher SARS-CoV-2 infected cell types, the consequent host immune response and their interplay in the lung of COVID-19 patients. Design: We analyzed single-cell RNA sequencing (scRNA-seq) data of lung samples from 17 subjects (6 severe COVID-19 patients, 3 mild patients who recovered and 8 healthy controls). The expression of SARS-CoV-2 receptors (ACE2 and TMPRSS2) was examined among different cell types in the lung. The immune cells infiltration patterns, their gene expression profiles, and the interplay of immune cells and SARS-CoV-2 target cells were further investigated. Results: Compared to healthy controls, the overall ACE2 (receptor of SARS-CoV-2) expression was significantly higher in lung epithelial cells of COVID-19 patients, in particular in ciliated cell, club cell and basal cell. Comparative transcriptome analysis of these lung epithelial cells of COVID-19 patients and healthy controls identified that SARS-CoV-2 infection activated pro-inflammatory signaling including interferon pathway and cytokine signaling. Moreover, we identified dysregulation of immune response in patients with COVID-19. In severe COVID-19 patients, significantly higher neutrophil, but lower T and NK cells in lung were observed along with markedly increased cytokines (CCL2, CCL3, CCL4, CCL7, CCL3L1 and CCL4L2) compared with healthy controls as well as mild patients who recovered. The cytotoxic phenotypes were shown in lung T and NK cells of severe patients as evidenced by enhanced IFNγ, Granulysin, Granzyme B and Perforin expression. Moreover, SARS-CoV-2 infection altered the community interplay of lung epithelial cells and immune cells: the interaction between epithelial cells with macrophage, T and NK cell was stronger, but their interaction with neutrophils was lost in COVID-19 patients compared to healthy controls. Conclusions: SARS-CoV-2 infection activates pro-inflammatory signaling in lung epithelial cells expressing ACE2 and causes dysregulation of immune response to release more pro-inflammatory cytokines. Moreover, SARS-CoV-2 infection breaks the interplay of lung epithelial cells and immune cells.

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SFPQ rescues F508del-CFTR expression and function in cystic fibrosis bronchial epithelial cells

Scientific Reports ◽

10.1038/s41598-021-96141-w ◽

2021 ◽

Vol 11 (1) ◽

Author(s):

Parameet Kumar ◽

Dharmendra Kumar Soni ◽

Chaitali Sen ◽

Mads B. Larsen ◽

Krystyna Mazan-Mamczarz ◽

...

Keyword(s):

Cystic Fibrosis ◽

Epithelial Cells ◽

Molecular Mechanisms ◽

Rna Binding ◽

Regulation Of Gene Expression ◽

Lung Epithelial Cells ◽

Regulation Of Expression ◽

Trafficking Defects ◽

And Function

AbstractCystic fibrosis (CF) occurs as a result of mutations in the cystic fibrosis transmembrane conductance regulator (CFTR) gene, which lead to misfolding, trafficking defects, and impaired function of the CFTR protein. Splicing factor proline/glutamine-rich (SFPQ) is a multifunctional nuclear RNA-binding protein (RBP) implicated in the regulation of gene expression pathways and intracellular trafficking. Here, we investigated the role of SFPQ in the regulation of the expression and function of F508del-CFTR in CF lung epithelial cells. We find that the expression of SFPQ is reduced in F508del-CFTR CF epithelial cells compared to WT-CFTR control cells. Interestingly, the overexpression of SFPQ in CF cells increases the expression as well as rescues the function of F508del-CFTR. Further, comprehensive transcriptome analyses indicate that SFPQ plays a key role in activating the mutant F508del-CFTR by modulating several cellular signaling pathways. This is the first report on the role of SFPQ in the regulation of expression and function of F508del-CFTR in CF lung disease. Our findings provide new insights into SFPQ-mediated molecular mechanisms and point to possible novel epigenetic therapeutic targets for CF and related pulmonary diseases.

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Hypoxia-Induced Epithelial-Mesenchymal Transition Is Involved in Bleomycin-Induced Lung Fibrosis

BioMed Research International ◽

10.1155/2015/232791 ◽

2015 ◽

Vol 2015 ◽

pp. 1-10 ◽

Cited By ~ 11

Author(s):

Liang Guo ◽

Jun-mei Xu ◽

Lei Liu ◽

Su-mei Liu ◽

Rong Zhu

Keyword(s):

P38 Mapk ◽

Lung Fibrosis ◽

Molecular Mechanisms ◽

Epithelial Mesenchymal Transition ◽

Severe Disease ◽

Progressive Increase ◽

Lung Epithelial Cells ◽

Cellular Mechanisms ◽

Mesenchymal Transition ◽

Protein Levels

Pulmonary fibrosis is a severe disease that contributes to the morbidity and mortality of a number of lung diseases. However, the molecular and cellular mechanisms leading to lung fibrosis are poorly understood. This study investigated the roles of epithelial-mesenchymal transition (EMT) and the associated molecular mechanisms in bleomycin-induced lung fibrosis. The bleomycin-induced fibrosis animal model was established by intratracheal injection of a single dose of bleomycin. Protein expression was measured by Western blot, immunohistochemistry, and immunofluorescence. Typical lesions of lung fibrosis were observed 1 week after bleomycin injection. A progressive increase in MMP-2, S100A4,α-SMA, HIF-1α, ZEB1, CD44, phospho-p44/42 (p-p44/42), and phospho-p38 MAPK (p-p38) protein levels as well as activation of EMT was observed in the lung tissues of bleomycin mice. Hypoxia increased HIF-1αand ZEB1 expression and activated EMT in H358 cells. Also, continuous incubation of cells under mild hypoxic conditions increased CD44, p-p44/42, and p-p38 protein levels in H358 cells, which correlated with the increase in S100A4 expression. In conclusion, bleomycin induces progressive lung fibrosis, which may be associated with activation of EMT. The fibrosis-induced hypoxia may further activate EMT in distal alveoli through a hypoxia-HIF-1α-ZEB1 pathway and promote the differentiation of lung epithelial cells into fibroblasts through phosphorylation of p38 MAPK and Erk1/2 proteins.

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Characterization of Nitric Oxide (NO)-Induced Cell Death in Lung Epithelial Cells

Tuberculosis and Respiratory Diseases ◽

10.4046/trd.2004.56.2.187 ◽

2004 ◽

Vol 56 (2) ◽

pp. 187

Author(s):

Wha Shim Yong ◽

Youn Seup Kim ◽

Jae Seuk Park ◽

Young Koo Jee ◽

Kye Young Lee

Keyword(s):

Nitric Oxide ◽

Cell Death ◽

Epithelial Cells ◽

Lung Epithelial Cells ◽

Lung Epithelial

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Molecular basis of disregulation of programmed lymphocytes’ death in chronic viral infection

Bulletin of Siberian Medicine ◽

10.20538/1682-0363-2006-2-23-34 ◽

2006 ◽

Vol 5 (2) ◽

pp. 23-34

Author(s):

V. V. Novitsky ◽

N. V. Ryazantseva ◽

O. B. Zhoukova

Keyword(s):

Cell Death ◽

Programmed Cell Death ◽

Viral Infection ◽

Immune Cells ◽

Molecular Basis ◽

Molecular Mechanisms ◽

Recent Literature ◽

Chronic Viral Infection ◽

Persistent Viruses

The review analyses information from recent literature and results of the authors’ own investigations concerning imbalance of programmed cell death in forming chronic viral infection. Molecular mechanisms of apoptosis modulation of immune cells by persistent viruses are discussed in the article.

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