Flow Cytometry Underestimates and Planimetry Overestimates Alveolar Epithelial Type 2 Cell Expansion after Lung Injury

Chronic obstructive pulmonary disease is a leading cause of mortality globally, with no effective therapy yet established. Adipose tissue-derived stem cells (ADSCs) are useful for ameliorating lung injury in animal models. However, whether ADSCs differentiate into functional cells remains uncertain, and no study has reported on the mechanism by which ADSCs improve lung functionality. Thus, in this study, we examined whether ADSCs differentiate into lung alveolar cells and are able to ameliorate lung injury caused by elastase-induced emphysema in model mice. Here, we induced ADSCs to differentiate into type 2 alveolar epithelial cells in vitro. We demonstrated that ADSCs can differentiate into type 2 alveolar epithelial cells in an elastase-induced emphysematous lung and that ADSCs improve pulmonary function of emphysema model mice, as determined with spirometry and 129Xe MRI. These data revealed a novel function for ADSCs in promoting repair of the damaged lung by direct differentiation into alveolar epithelial cells.

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Role Of The Type 2 Alveolar Epithelial Cells In An Experimental Model Of Acute Lung Injury

10.1164/ajrccm-conference.2012.185.1_meetingabstracts.a6317 ◽

2012 ◽

Author(s):

Sonia Garcia-Hernandez ◽

Ricardo Gutierrez ◽

Lucio Diaz-Flores ◽

Jesus Villar ◽

Francisco Valladares

Keyword(s):

Acute Lung Injury ◽

Epithelial Cells ◽

Lung Injury ◽

Experimental Model ◽

Alveolar Epithelial Cells ◽

Alveolar Epithelial

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Lung injury induces alveolar type 2 cell hypertrophy and polyploidy with implications for repair and regeneration

10.1101/2021.08.10.455833 ◽

2021 ◽

Author(s):

Anthea Weng ◽

Mariana Maciel-Herrerias ◽

Satoshi J Watanabe ◽

Annette S. Flozak ◽

Lynn Welch ◽

...

Keyword(s):

Lung Injury ◽

Ex Vivo ◽

Alveolar Type ◽

Lung Epithelium ◽

Post Injury ◽

Alveolar Epithelial ◽

Cell Hypertrophy ◽

Alveolar Epithelial Injury ◽

Distal Lung

Epithelial polyploidization post-injury is a conserved phenomenon, recently shown to improve barrier restoration during wound healing. Whether lung injury can induce alveolar epithelial polyploidy is not known. We show that bleomycin injury induces AT2 cell hypertrophy and polyploidy. AT2 polyploidization is also seen in short term ex vivo cultures, where AT2-to-AT1 trans-differentiation is associated with substantial binucleation due to failed cytokinesis. Both hypertrophic and polyploid features of AT2 cells can be attenuated by inhibiting the integrated stress response (ISR) using the small molecule ISRIB. These data suggest that AT2 polyploidization may be a feature of alveolar epithelial injury. As AT2 cells serve as facultative progenitors for the distal lung epithelium, a propensity for injury-induced binucleation has implications for AT2 self-renewal and regenerative potential upon re-injury, which may benefit from targeting the ISR.

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Impact of Regulatory T Cells on Type 2 Alveolar Epithelial Cell Transcriptomes during Resolution of Acute Lung Injury and Contributions of IFN-γ

American Journal of Respiratory Cell and Molecular Biology ◽

10.1165/rcmb.2019-0399oc ◽

2020 ◽

Vol 63 (4) ◽

pp. 464-477 ◽

Cited By ~ 2

Author(s):

Jason R. Mock ◽

Catherine F. Dial ◽

Miriya K. Tune ◽

Rodney C. Gilmore ◽

Wanda K. O’Neal ◽

...

Keyword(s):

T Cells ◽

Acute Lung Injury ◽

Epithelial Cell ◽

Regulatory T Cells ◽

Lung Injury ◽

Alveolar Epithelial Cell ◽

Alveolar Epithelial ◽

Ifn Γ

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Estimation of absolute number of alveolar epithelial type 2 cells in mouse lungs: a comparison between stereology and flow cytometry

Journal of Microscopy ◽

10.1111/jmi.12800 ◽

2019 ◽

Vol 275 (1) ◽

pp. 36-50 ◽

Cited By ~ 5

Author(s):

GEORGY DZHURAEV ◽

JOSÉ ALBERTO RODRÍGUEZ‐CASTILLO ◽

JORDI RUIZ‐CAMP ◽

ISABELLE SALWIG ◽

MARTIN SZIBOR ◽

...

Keyword(s):

Flow Cytometry ◽

Absolute Number ◽

Alveolar Epithelial ◽

Mouse Lungs

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Faculty Opinions recommendation of Programmed cell death 1 suppresses B-1b cell expansion and long-lived IgG production in response to T cell-independent type 2 antigens.

Faculty Opinions – Post-Publication Peer Review of the Biomedical Literature ◽

10.3410/f.13409131.14780161 ◽

2011 ◽

Author(s):

Dorothy Yuan

Keyword(s):

Cell Death ◽

T Cell ◽

Programmed Cell Death ◽

Cell Expansion ◽

Programmed Cell Death 1

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Tumor necrosis factor-α small interfering RNA alveolar epithelial cell-targeting nanoparticles reduce lung injury in C57BL/6J mice with sepsis

Journal of International Medical Research ◽

10.1177/0300060520984652 ◽

2021 ◽

Vol 49 (1) ◽

pp. 030006052098465

Author(s):

Like Qian ◽

Xi Yin ◽

Jiahao Ji ◽

Zhengli Chen ◽

He Fang ◽

...

Keyword(s):

Tumor Necrosis Factor ◽

Epithelial Cell ◽

Lung Injury ◽

Tumor Necrosis ◽

Alveolar Epithelial Cell ◽

Weight Ratio ◽

B Cell Lymphoma ◽

Alveolar Epithelial ◽

Tnf Α ◽

Necrosis Factor

Background The role of tumor necrosis factor (TNF)-α small interfering (si)RNA alveolar epithelial cell (AEC)-targeting nanoparticles in lung injury is unclear. Methods Sixty C57BL/6J mice with sepsis were divided into normal, control, sham, 25 mg/kg, 50 mg/kg, and 100 mg/kg siRNA AEC-targeting nanoparticles groups (n = 10 per group). The wet:dry lung weight ratio, and hematoxylin and eosin staining, western blotting, and enzyme-linked immunosorbent assays for inflammatory factors were conducted to compare differences among groups. Results The wet:dry ratio was significantly lower in control and sham groups than other groups. TNF-α siRNA AEC-targeting nanoparticles significantly reduced the number of eosinophils, with significantly lower numbers in the 50 mg/kg group than in 25 mg/kg and 100 mg/kg groups. The nanoparticles also significantly reduced the expression of TNF-α, B-cell lymphoma-2, caspase 3, interleukin (IL)-1β, and IL-6, with TNF-α expression being significantly lower in the 50 mg/kg group than in 25 mg/kg and 100 mg/kg groups. Conclusion TNF-α siRNA AEC-targeting nanoparticles appear to be effective at improving lung injury-related sepsis, and 50 mg/kg may be a preferred dose option for administration.

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Dexmedetomidine alleviates pulmonary edema through the epithelial sodium channel (ENaC) via the PI3K/Akt/Nedd4-2 pathway in LPS-induced acute lung injury

Immunologic Research ◽

10.1007/s12026-021-09176-6 ◽

2021 ◽

Author(s):

Yuanxu Jiang ◽

Mingzhu Xia ◽

Jing Xu ◽

Qiang Huang ◽

Zhongliang Dai ◽

...

Keyword(s):

Acute Lung Injury ◽

Lung Injury ◽

Sodium Channel ◽

Pulmonary Edema ◽

Cell Injury ◽

A549 Cells ◽

Alveolar Epithelial ◽

Phosphorylated Akt ◽

Epithelial Sodium Channel Enac

AbstractDexmedetomidine (Dex), a highly selective α2-adrenergic receptor (α2AR) agonist, has an anti-inflammatory property and can alleviate pulmonary edema in lipopolysaccharide (LPS)-induced acute lung injury (ALI), but the mechanism is still unclear. In this study, we attempted to investigate the effect of Dex on alveolar epithelial sodium channel (ENaC) in the modulation of alveolar fluid clearance (AFC) and the underlying mechanism. Lipopolysaccharide (LPS) was used to induce acute lung injury (ALI) in rats and alveolar epithelial cell injury in A549 cells. In vivo, Dex markedly reduced pulmonary edema induced by LPS through promoting AFC, prevented LPS-induced downregulation of α-, β-, and γ-ENaC expression, attenuated inflammatory cell infiltration in lung tissue, reduced the concentrations of TNF-α, IL-1β, and IL-6, and increased concentrations of IL-10 in bronchoalveolar lavage fluid (BALF). In A549 cells stimulated with LPS, Dex attenuated LPS-mediated cell injury and the downregulation of α-, β-, and γ-ENaC expression. However, all of these effects were blocked by the PI3K inhibitor LY294002, suggesting that the protective role of Dex is PI3K-dependent. Additionally, Dex increased the expression of phosphorylated Akt and reduced the expression of Nedd4-2, while LY294002 reversed the effect of Dex in vivo and in vitro. Furthermore, insulin-like growth factor (IGF)-1, a PI3K agonists, promoted the expression of phosphorylated Akt and reduced the expression of Nedd4-2 in LPS-stimulated A549 cells, indicating that Dex worked through PI3K, and Akt and Nedd4-2 are downstream of PI3K. In conclusion, Dex alleviates pulmonary edema by suppressing inflammatory response in LPS-induced ALI, and the mechanism is partly related to the upregulation of ENaC expression via the PI3K/Akt/Nedd4-2 signaling pathway.

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K2P2.1 (TREK-1) potassium channel activation protects against hyperoxia-induced lung injury

Scientific Reports ◽

10.1038/s41598-020-78886-y ◽

2020 ◽

Vol 10 (1) ◽

Author(s):

Tatiana Zyrianova ◽

Benjamin Lopez ◽

Riccardo Olcese ◽

John Belperio ◽

Christopher M. Waters ◽

...

Keyword(s):

Lung Injury ◽

Lung Compliance ◽

Alveolar Epithelial Cells ◽

Pharmacological Intervention ◽

Alveolar Epithelial ◽

Protein Levels ◽

Cell Counts ◽

Novel Approach ◽

Intracellular Ca ◽

Cell Depolarization

AbstractNo targeted therapies exist to counteract Hyperoxia (HO)-induced Acute Lung Injury (HALI). We previously found that HO downregulates alveolar K2P2.1 (TREK-1) K+ channels, which results in worsening lung injury. This decrease in TREK-1 levels leaves a subset of channels amendable to pharmacological intervention. Therefore, we hypothesized that TREK-1 activation protects against HALI. We treated HO-exposed mice and primary alveolar epithelial cells (AECs) with the novel TREK-1 activators ML335 and BL1249, and quantified physiological, histological, and biochemical lung injury markers. We determined the effects of these drugs on epithelial TREK-1 currents, plasma membrane potential (Em), and intracellular Ca2+ (iCa) concentrations using fluorometric assays, and blocked voltage-gated Ca2+ channels (CaV) as a downstream mechanism of cytokine secretion. Once-daily, intra-tracheal injections of HO-exposed mice with ML335 or BL1249 improved lung compliance, histological lung injury scores, broncho-alveolar lavage protein levels and cell counts, and IL-6 and IP-10 concentrations. TREK-1 activation also decreased IL-6, IP-10, and CCL-2 secretion from primary AECs. Mechanistically, ML335 and BL1249 induced TREK-1 currents in AECs, counteracted HO-induced cell depolarization, and lowered iCa2+ concentrations. In addition, CCL-2 secretion was decreased after L-type CaV inhibition. Therefore, Em stabilization with TREK-1 activators may represent a novel approach to counteract HALI.

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