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Rathnayake K, Patel U, Hunt EC, Singh N. Fabrication of a Dual-Targeted Liposome-Coated Mesoporous Silica Core-Shell Nanoassembly for Targeted Cancer Therapy. ACS OMEGA 2023; 8:34481-34498. [PMID: 37779923 PMCID: PMC10536893 DOI: 10.1021/acsomega.3c02901] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 04/27/2023] [Accepted: 09/04/2023] [Indexed: 10/03/2023]
Abstract
Nanoparticles have been suggested as drug-delivery systems for chemotherapeutic drugs to allow for controlled drug release profiles and selectivity to target cancer cells. In addition, nanoparticles can be used for the in situ generation and amplification of reactive oxygen species (ROS), which have been shown to be a promising strategy for cancer treatment. Thus, a targeted nanoscale drug-delivery platform could be used to synergistically improve cancer treatment by the action of chemotherapeutic drugs and ROS generation. Herein, we propose a promising chemotherapy strategy where the drug-loaded nanoparticles generate high doses of ROS together with the loaded ROS-generating chemotherapeutic drugs, which can damage the mitochondria and activate cell death, potentiating the therapeutic outcome in cancer therapy. In the present study, we have developed a dual-targeted drug-delivery nanoassembly consisting of a mesoporous silica core loaded with the chemotherapeutic, ROS-generating drug, paclitaxel (Px), and coated with a liposome layer for controlled drug release. Two different lung cancer-targeting ligands, folic acid and peptide GE11, were used to target the overexpressed nonsmall lung cancer receptors to create the final nanoassembly (MSN@Px) L-GF. Upon endocytosis by the cancer cells, the liposome layer was degraded by the intracellular lipases, and the drug was rapidly released at a rate of 65% within the first 20 h. In vitro studies confirmed that this nanoassembly was 8-fold more effective in cancer therapy compared to the free drug Px.
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Affiliation(s)
- Kavini Rathnayake
- Department of Chemistry, The
University of Alabama in Huntsville, Huntsville, Alabama 35899, United States
| | - Unnati Patel
- Department of Chemistry, The
University of Alabama in Huntsville, Huntsville, Alabama 35899, United States
| | - Emily C. Hunt
- Department of Chemistry, The
University of Alabama in Huntsville, Huntsville, Alabama 35899, United States
| | - Nirupama Singh
- Department of Chemistry, The
University of Alabama in Huntsville, Huntsville, Alabama 35899, United States
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2
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Patel U, Rathnayake K, Singh N, Hunt EC. Dual Targeted Delivery of Liposomal Hybrid Gold Nano-Assembly for Enhanced Photothermal Therapy against Lung Carcinomas. ACS APPLIED BIO MATERIALS 2023; 6:1915-1933. [PMID: 37083301 DOI: 10.1021/acsabm.3c00130] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 04/22/2023]
Abstract
The delivery and accumulation of therapeutic drugs into cancer cells without affecting healthy cells are a major challenge for antitumor therapy. Here, we report the synthesis of a liposomal hybrid gold nano-assembly with enhanced photothermal activity for lung cancer treatment. The core components of the nano-assembly include gold nanorods coated with a mesoporous silica shell that offers an excellent drug-loading surface for encapsulation of doxorubicin. To enhance the photothermal capacity of nano-assembly, IR 780 dye was loaded inside a thermo-sensitive liposome, and then, the core nano-assembly was wrapped within the liposome, and GE-11 peptide and folic acid were conjugated onto the surface of the liposome to give the final nano-assembly [(GM@Dox) LI]-PF. The dual targeting approach of [(GM@Dox) LI]-PF leads to enhanced cellular uptake and improves the accumulation of nano-assemblies in cancer cells that overexpress the epidermal growth factor receptor and folate. The exposure of near-infrared laser irradiation can trigger photothermal-induced structural disruption of the nano-assembly, which allows for the precise and controllable release of Dox at targeted sites. Additionally, chemo-photothermal therapy was shown to be 11 times more effective in cancer cell treatment when compared to Dox alone. Our systematic study suggests that the nano-assemblies facilitate the cancer cells undergoing apoptosis via an intrinsic mitochondrial pathway that can be directly triggered by the chemo-photothermal treatment. This study offers an appealing candidate that holds great promise for synergistic cancer treatment.
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Affiliation(s)
- Unnati Patel
- Department of Chemistry, The University of Alabama in Huntsville, Huntsville, Alabama 35899, United States
| | - Kavini Rathnayake
- Department of Chemistry, The University of Alabama in Huntsville, Huntsville, Alabama 35899, United States
| | - Nirupama Singh
- Department of Chemistry, The University of Alabama in Huntsville, Huntsville, Alabama 35899, United States
| | - Emily C Hunt
- Department of Chemistry, The University of Alabama in Huntsville, Huntsville, Alabama 35899, United States
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3
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Parvez S, Karole A, Mudavath SL. Fabrication, physicochemical characterization and In vitro anticancer activity of nerolidol encapsulated solid lipid nanoparticles in human colorectal cell line. Colloids Surf B Biointerfaces 2022; 215:112520. [PMID: 35489319 DOI: 10.1016/j.colsurfb.2022.112520] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/06/2021] [Revised: 03/15/2022] [Accepted: 04/21/2022] [Indexed: 12/11/2022]
Abstract
Nerolidol is a sesquiterpene that occurs naturally and possesses a diverse set of biological characteristics including anticancer activity but has limited solubility, bioavailability, and fast hepatic metabolism. The goal of this study was to develop a nanocarrier system encapsulating a bioactive as well as to evaluate its efficacy in Human Colorectal Cell Line. Solid lipid nanoparticles were fabricated by the emulsion solvent evaporation method and determined the particle size, polydispersity index (PDI), zeta potential, % entrapment efficiency, scanning electron microscopy (SEM), transmission electron microscopy (TEM), drug-excipient interaction study of developed nanoparticles. MTT assay was used to assess the cytotoxicity of formulations in vitro. Nerolidol loaded solid lipid nanoparticles (NR-LNPs) have presented satisfactory properties: mean particles diameter of 159 ± 4.89 nm, PDI of 0.32 ± 0.01, the zeta potential value was found to be -10 ± 1.97 and % entrapment efficiency 71.3% ± 6.11. The formulations demonstrated enhanced biological activity due to enhanced solubility and stability of the bioactive after loading into a nanoformulation along with the better internalization inside the cells.
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Affiliation(s)
- Shabi Parvez
- Infectious Disease Biology Laboratory, Institute of Nano Science and Technology, Knowledge City, Sector 81, Mohali, Punjab 140306, India
| | - Archana Karole
- Infectious Disease Biology Laboratory, Institute of Nano Science and Technology, Knowledge City, Sector 81, Mohali, Punjab 140306, India
| | - Shyam Lal Mudavath
- Infectious Disease Biology Laboratory, Institute of Nano Science and Technology, Knowledge City, Sector 81, Mohali, Punjab 140306, India.
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Karole A, Parvez S, Thakur RS, Mudavath SL. Effervescent based nano-gas carrier enhanced the bioavailability of poorly aqueous soluble drug: A comprehensive mechanistic understanding. J Drug Deliv Sci Technol 2022. [DOI: 10.1016/j.jddst.2022.103167] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
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5
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Genshaft AS, Ziegler CGK, Tzouanas CN, Mead BE, Jaeger AM, Navia AW, King RP, Mana MD, Huang S, Mitsialis V, Snapper SB, Yilmaz ÖH, Jacks T, Van Humbeck JF, Shalek AK. Live cell tagging tracking and isolation for spatial transcriptomics using photoactivatable cell dyes. Nat Commun 2021; 12:4995. [PMID: 34404785 PMCID: PMC8371137 DOI: 10.1038/s41467-021-25279-y] [Citation(s) in RCA: 20] [Impact Index Per Article: 6.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/31/2021] [Accepted: 07/26/2021] [Indexed: 12/30/2022] Open
Abstract
A cell's phenotype and function are influenced by dynamic interactions with its microenvironment. To examine cellular spatiotemporal activity, we developed SPACECAT-Spatially PhotoActivatable Color Encoded Cell Address Tags-to annotate, track, and isolate cells while preserving viability. In SPACECAT, samples are stained with photocaged fluorescent molecules, and cells are labeled by uncaging those molecules with user-patterned near-UV light. SPACECAT offers single-cell precision and temporal stability across diverse cell and tissue types. Illustratively, we target crypt-like regions in patient-derived intestinal organoids to enrich for stem-like and actively mitotic cells, matching literature expectations. Moreover, we apply SPACECAT to ex vivo tissue sections from four healthy organs and an autochthonous lung tumor model. Lastly, we provide a computational framework to identify spatially-biased transcriptome patterns and enriched phenotypes. This minimally perturbative and broadly applicable method links cellular spatiotemporal and/or behavioral phenotypes with diverse downstream assays, enabling insights into the connections between tissue microenvironments and (dys)function.
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Affiliation(s)
- Alex S Genshaft
- Institute for Medical Engineering & Science, MIT, Cambridge, MA, USA
- Department of Chemistry, MIT, Cambridge, MA, USA
- Koch Institute for Integrative Cancer Research, MIT, Cambridge, MA, USA
- The Ragon Institute of MGH, MIT and Harvard, Cambridge, MA, USA
- Broad Institute of MIT and Harvard, Cambridge, MA, USA
- Harvard-MIT Program in Health Sciences and Technology, Harvard Medical School, Cambridge, MA, USA
| | - Carly G K Ziegler
- Institute for Medical Engineering & Science, MIT, Cambridge, MA, USA
- Department of Chemistry, MIT, Cambridge, MA, USA
- Koch Institute for Integrative Cancer Research, MIT, Cambridge, MA, USA
- The Ragon Institute of MGH, MIT and Harvard, Cambridge, MA, USA
- Broad Institute of MIT and Harvard, Cambridge, MA, USA
- Harvard-MIT Program in Health Sciences and Technology, Harvard Medical School, Cambridge, MA, USA
| | - Constantine N Tzouanas
- Institute for Medical Engineering & Science, MIT, Cambridge, MA, USA
- Department of Chemistry, MIT, Cambridge, MA, USA
- Koch Institute for Integrative Cancer Research, MIT, Cambridge, MA, USA
- The Ragon Institute of MGH, MIT and Harvard, Cambridge, MA, USA
- Broad Institute of MIT and Harvard, Cambridge, MA, USA
- Harvard-MIT Program in Health Sciences and Technology, Harvard Medical School, Cambridge, MA, USA
| | - Benjamin E Mead
- Institute for Medical Engineering & Science, MIT, Cambridge, MA, USA
- Department of Chemistry, MIT, Cambridge, MA, USA
- Koch Institute for Integrative Cancer Research, MIT, Cambridge, MA, USA
- The Ragon Institute of MGH, MIT and Harvard, Cambridge, MA, USA
- Broad Institute of MIT and Harvard, Cambridge, MA, USA
- Harvard-MIT Program in Health Sciences and Technology, Harvard Medical School, Cambridge, MA, USA
| | - Alex M Jaeger
- Koch Institute for Integrative Cancer Research, MIT, Cambridge, MA, USA
| | - Andrew W Navia
- Institute for Medical Engineering & Science, MIT, Cambridge, MA, USA
- Department of Chemistry, MIT, Cambridge, MA, USA
- Koch Institute for Integrative Cancer Research, MIT, Cambridge, MA, USA
- The Ragon Institute of MGH, MIT and Harvard, Cambridge, MA, USA
- Broad Institute of MIT and Harvard, Cambridge, MA, USA
- Harvard-MIT Program in Health Sciences and Technology, Harvard Medical School, Cambridge, MA, USA
| | - Ryan P King
- Department of Chemistry, MIT, Cambridge, MA, USA
| | - Miyeko D Mana
- Koch Institute for Integrative Cancer Research, MIT, Cambridge, MA, USA
| | - Siyi Huang
- The Ragon Institute of MGH, MIT and Harvard, Cambridge, MA, USA
- Department of Immunology & HMS Center for Immune Imaging, Harvard Medical School, Boston, MA, USA
| | - Vanessa Mitsialis
- Division of Gastroenterology, Hepatology, and Nutrition, Boston Children's Hospital, Boston, MA, USA
- Division of Gastroenterology, Brigham and Women's Hospital, Boston, MA, USA
| | - Scott B Snapper
- Division of Gastroenterology, Hepatology, and Nutrition, Boston Children's Hospital, Boston, MA, USA
- Division of Gastroenterology, Brigham and Women's Hospital, Boston, MA, USA
| | - Ömer H Yilmaz
- Koch Institute for Integrative Cancer Research, MIT, Cambridge, MA, USA
- Broad Institute of MIT and Harvard, Cambridge, MA, USA
- Department of Biology, Massachusetts Institute of Technology, Cambridge, MA, USA
- Department of Pathology, Massachusetts General Hospital and Harvard Medical School, Boston, MA, USA
| | - Tyler Jacks
- Koch Institute for Integrative Cancer Research, MIT, Cambridge, MA, USA
- Howard Hughes Medical Institute, Chevy Chase, MD, USA
| | | | - Alex K Shalek
- Institute for Medical Engineering & Science, MIT, Cambridge, MA, USA.
- Department of Chemistry, MIT, Cambridge, MA, USA.
- Koch Institute for Integrative Cancer Research, MIT, Cambridge, MA, USA.
- The Ragon Institute of MGH, MIT and Harvard, Cambridge, MA, USA.
- Broad Institute of MIT and Harvard, Cambridge, MA, USA.
- Harvard-MIT Program in Health Sciences and Technology, Harvard Medical School, Cambridge, MA, USA.
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Zhang Y, Huang WJ, Yang QR, Zhang HD, Zhu XJ, Zeng M, Zhou X, Wang ZY, Li WJ, Jing HS, Zhang XB, Shi YP, Hu H, Yan HX, Li ZH, Zhai B. Cryopreserved biopsy tissues of rectal cancer liver metastasis for assessment of anticancer drug response in vitro and in vivo. Oncol Rep 2019; 43:405-414. [PMID: 31894341 PMCID: PMC6967191 DOI: 10.3892/or.2019.7450] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/17/2018] [Accepted: 06/14/2019] [Indexed: 02/07/2023] Open
Abstract
Living tumors are of great scientific value for clinical medicine and basic research, especially for drug testing. An increasing number of drug tests fail due to the use of imperfect models. The aim of the present study was to develop a novel method combining vitrification-based cryopreservation of tumor biopsies and precision-cut slice cultivation for the assessment of anticancer drug responses. Biological characteristics of rectal cancer liver metastasis biopsies could be retained by vitrification-based cryopreservation. The patient-derived xenograft models were successfully established using both fresh and warmed biopsy tissues. Precision-cut slicing provided a similar three-dimensional architecture and heterogeneity to the original tumor. The positive drug responses in the xenograft model were consistent with those in precision-cut slice cultures in vitro. The present study demonstrated that live tumor biopsies could be preserved using vitrification-based cryopreservation. The warmed tissues developed xenograft tumors, which were also useful for either in vivo or in vitro anticancer drug testing. Precision-cut slices derived from the warmed tissues provided an efficient tool to assess anticancer drug response in vitro.
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Affiliation(s)
- Yuan Zhang
- Department of Tumor Interventional Oncology, Renji Hospital, School of Medicine, Shanghai Jiaotong University, Shanghai 200127, P.R. China
| | - Wei-Jian Huang
- International Cooperation Laboratory on Signal Transduction, Eastern Hepatobiliary Surgery Institute, The Second Military Medical University, Shanghai 200438, P.R. China
| | - Qiu-Rui Yang
- Shanghai Celliver Biotechnology Co., Shanghai 201203, P.R. China
| | - Hong-Dan Zhang
- Shanghai Celliver Biotechnology Co., Shanghai 201203, P.R. China
| | - Xue-Jing Zhu
- Shanghai Celliver Biotechnology Co., Shanghai 201203, P.R. China
| | - Min Zeng
- International Cooperation Laboratory on Signal Transduction, Eastern Hepatobiliary Surgery Institute, The Second Military Medical University, Shanghai 200438, P.R. China
| | - Xu Zhou
- International Cooperation Laboratory on Signal Transduction, Eastern Hepatobiliary Surgery Institute, The Second Military Medical University, Shanghai 200438, P.R. China
| | - Zhen-Yu Wang
- Department of Tumor Interventional Oncology, Renji Hospital, School of Medicine, Shanghai Jiaotong University, Shanghai 200127, P.R. China
| | - Wei-Jian Li
- Department of Tumor Interventional Oncology, Renji Hospital, School of Medicine, Shanghai Jiaotong University, Shanghai 200127, P.R. China
| | - Hong-Shu Jing
- Department of Tumor Interventional Oncology, Renji Hospital, School of Medicine, Shanghai Jiaotong University, Shanghai 200127, P.R. China
| | - Xue-Bin Zhang
- Department of Tumor Interventional Oncology, Renji Hospital, School of Medicine, Shanghai Jiaotong University, Shanghai 200127, P.R. China
| | - Yao-Ping Shi
- Department of Tumor Interventional Oncology, Renji Hospital, School of Medicine, Shanghai Jiaotong University, Shanghai 200127, P.R. China
| | - Hao Hu
- Department of Tumor Interventional Oncology, Renji Hospital, School of Medicine, Shanghai Jiaotong University, Shanghai 200127, P.R. China
| | - He-Xin Yan
- Department of Tumor Interventional Oncology, Renji Hospital, School of Medicine, Shanghai Jiaotong University, Shanghai 200127, P.R. China
| | - Zong-Hai Li
- State Key Laboratory of Oncogenes and Related Genes, Shanghai Cancer Institute, Renji Hospital, School of Medicine, Shanghai Jiaotong University, Shanghai 200032, P.R. China
| | - Bo Zhai
- Department of Tumor Interventional Oncology, Renji Hospital, School of Medicine, Shanghai Jiaotong University, Shanghai 200127, P.R. China
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Brand JD, Lazrak A, Trombley JE, Shei RJ, Adewale AT, Tipper JL, Yu Z, Ashtekar AR, Rowe SM, Matalon S, Harrod KS. Influenza-mediated reduction of lung epithelial ion channel activity leads to dysregulated pulmonary fluid homeostasis. JCI Insight 2018; 3:123467. [PMID: 30333319 DOI: 10.1172/jci.insight.123467] [Citation(s) in RCA: 43] [Impact Index Per Article: 7.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/13/2018] [Accepted: 09/06/2018] [Indexed: 02/06/2023] Open
Abstract
Severe influenza (IAV) infection can develop into bronchopneumonia and edema, leading to acquired respiratory distress syndrome (ARDS) and pathophysiology. Underlying causes for pulmonary edema and aberrant fluid regulation largely remain unknown, particularly regarding the role of viral-mediated mechanisms. Herein, we show that distinct IAV strains reduced the functions of the epithelial sodium channel (ENaC) and the cystic fibrosis transmembrane regulator (CFTR) in murine respiratory and alveolar epithelia in vivo, as assessed by measurements of nasal potential differences and single-cell electrophysiology. Reduced ion channel activity was distinctly limited to virally infected cells in vivo and not bystander uninfected lung epithelium. Multiple lines of evidence indicated ENaC and CFTR dysfunction during the acute infection period; however, only CFTR dysfunction persisted beyond the infection period. ENaC, CFTR, and Na,K-ATPase activities and protein levels were also reduced in virally infected human airway epithelial cells. Reduced ENaC and CFTR led to changes in airway surface liquid morphology of human tracheobronchial cultures and airways of IAV-infected mice. Pharmacologic correction of CFTR function ameliorated IAV-induced physiologic changes. These changes are consistent with mucous stasis and pulmonary edema; furthermore, they indicate that repurposing therapeutic interventions correcting CFTR dysfunction may be efficacious for treatment of IAV lung pathophysiology.
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Affiliation(s)
- Jeffrey D Brand
- Department of Anesthesiology and Perioperative Medicine, Division of Molecular and Translational Biomedicine
| | - Ahmed Lazrak
- Department of Anesthesiology and Perioperative Medicine, Division of Molecular and Translational Biomedicine
| | - John E Trombley
- Department of Anesthesiology and Perioperative Medicine, Division of Molecular and Translational Biomedicine
| | - Ren-Jay Shei
- Department of Medicine, Division of Pulmonary, Allergy, and Critical Care, and.,Gregory Fleming James Cystic Fibrosis Research Center, School of Medicine, University of Alabama at Birmingham, Birmingham, Alabama, USA
| | - A Timothy Adewale
- Gregory Fleming James Cystic Fibrosis Research Center, School of Medicine, University of Alabama at Birmingham, Birmingham, Alabama, USA
| | - Jennifer L Tipper
- Department of Anesthesiology and Perioperative Medicine, Division of Molecular and Translational Biomedicine
| | - Zhihong Yu
- Department of Anesthesiology and Perioperative Medicine, Division of Molecular and Translational Biomedicine
| | - Amit R Ashtekar
- Department of Anesthesiology and Perioperative Medicine, Division of Molecular and Translational Biomedicine
| | - Steven M Rowe
- Department of Medicine, Division of Pulmonary, Allergy, and Critical Care, and.,Gregory Fleming James Cystic Fibrosis Research Center, School of Medicine, University of Alabama at Birmingham, Birmingham, Alabama, USA
| | - Sadis Matalon
- Department of Anesthesiology and Perioperative Medicine, Division of Molecular and Translational Biomedicine
| | - Kevin S Harrod
- Department of Anesthesiology and Perioperative Medicine, Division of Molecular and Translational Biomedicine
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8
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Clement S, Chen W, Deng W, Goldys EM. X-ray radiation-induced and targeted photodynamic therapy with folic acid-conjugated biodegradable nanoconstructs. Int J Nanomedicine 2018; 13:3553-3570. [PMID: 29950835 PMCID: PMC6016269 DOI: 10.2147/ijn.s164967] [Citation(s) in RCA: 38] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/17/2023] Open
Abstract
INTRODUCTION The depth limitation of conventional photodynamic therapy (PDT) with visible electromagnetic radiation represents a challenge for the treatment of deep-seated tumors. MATERIALS AND METHODS To overcome this issue, we developed an X-ray-induced PDT system where poly(lactide-co-glycolide) (PLGA) polymeric nanoparticles (NPs) incorporating a photosensitizer (PS), verteporfin (VP), were triggered by 6 MeV X-ray radiation to generate cytotoxic singlet oxygen. The X-ray radiation used in this study allows this system to breakthrough the PDT depth barrier due to excellent penetration of 6 MeV X-ray radiation through biological tissue. In addition, the conjugation of our NPs with folic acid moieties enables specific targeting of HCT116 cancer cells that overexpress the folate receptors. We carried out physiochemical characterization of PLGA NPs, such as size distribution, zeta potential, morphology and in vitro release of VP. Cellular uptake activity and cell-killing effect of these NPs were also evaluated. RESULTS AND DISCUSSION Our results indicate that our nanoconstructs triggered by 6 MeV X-ray radiation yield enhanced PDT efficacy compared with the radiation alone. We attributed the X-ray-induced singlet oxygen generation from the PS, VP, to photoexcitation by Cherenkov radiation and/or reactive oxygen species generation facilitated by energetic secondary electrons produced in the tissue. CONCLUSION The cytotoxic effect caused by VP offers the possibility of enhancing the radiation therapy commonly prescribed for the treatment of cancer by simultaneous PDT.
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Affiliation(s)
- Sandhya Clement
- Australian Research Council Centre of Excellence for Nanoscale BioPhotonics (CNBP), Department of Physics and Astronomy, Macquarie University, Sydney, NSW, Australia
- The Graduate School of Biomedical Engineering, University of New South Wales, Sydney, NSW, Australia
| | - Wenjie Chen
- Australian Research Council Centre of Excellence for Nanoscale BioPhotonics (CNBP), Department of Physics and Astronomy, Macquarie University, Sydney, NSW, Australia
| | - Wei Deng
- Australian Research Council Centre of Excellence for Nanoscale BioPhotonics (CNBP), Department of Physics and Astronomy, Macquarie University, Sydney, NSW, Australia
- The Graduate School of Biomedical Engineering, University of New South Wales, Sydney, NSW, Australia
| | - Ewa M Goldys
- Australian Research Council Centre of Excellence for Nanoscale BioPhotonics (CNBP), Department of Physics and Astronomy, Macquarie University, Sydney, NSW, Australia
- The Graduate School of Biomedical Engineering, University of New South Wales, Sydney, NSW, Australia
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Matthay MA. Resolution of pulmonary edema. Thirty years of progress. Am J Respir Crit Care Med 2014; 189:1301-8. [PMID: 24881936 DOI: 10.1164/rccm.201403-0535oe] [Citation(s) in RCA: 108] [Impact Index Per Article: 10.8] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/11/2023] Open
Abstract
In the last 30 years, we have learned much about the molecular, cellular, and physiological mechanisms that regulate the resolution of pulmonary edema in both the normal and the injured lung. Although the physiological mechanisms responsible for the formation of pulmonary edema were identified by 1980, the mechanisms that explain the resolution of pulmonary edema were not well understood at that time. However, in the 1980s several investigators provided novel evidence that the primary mechanism for removal of alveolar edema fluid depended on active ion transport across the alveolar epithelium. Sodium enters through apical channels, primarily the epithelial sodium channel, and is pumped into the lung interstitium by basolaterally located Na/K-ATPase, thus creating a local osmotic gradient to reabsorb the water fraction of the edema fluid from the airspaces of the lungs. The resolution of alveolar edema across the normally tight epithelial barrier can be up-regulated by cyclic adenosine monophosphate (cAMP)-dependent mechanisms through adrenergic or dopamine receptor stimulation, and by several cAMP-independent mechanisms, including glucocorticoids, thyroid hormone, dopamine, and growth factors. Whereas resolution of alveolar edema in cardiogenic pulmonary edema can be rapid, the rate of edema resolution in most patients with acute respiratory distress syndrome (ARDS) is markedly impaired, a finding that correlates with higher mortality. Several mechanisms impair the resolution of alveolar edema in ARDS, including cell injury from unfavorable ventilator strategies or pathogens, hypoxia, cytokines, and oxidative stress. In patients with severe ARDS, alveolar epithelial cell death is a major mechanism that prevents the resolution of lung edema.
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Affiliation(s)
- Michael A Matthay
- Departments of Medicine and Anesthesia and Cardiovascular Research Institute, University of California, San Francisco, San Francisco, California
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Liberati TA, Randle MR, Toth LA. In vitrolung slices: a powerful approach for assessment of lung pathophysiology. Expert Rev Mol Diagn 2014; 10:501-8. [DOI: 10.1586/erm.10.21] [Citation(s) in RCA: 51] [Impact Index Per Article: 5.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/04/2023]
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11
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Liberati TA, Trammell RA, Randle M, Barrett S, Toth LA. Cytokine and chemokine responses of lung exposed to surrogate viral and bacterial infections. Comp Med 2013; 63:114-126. [PMID: 23582418 PMCID: PMC3625052] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/13/2012] [Revised: 09/16/2012] [Accepted: 10/11/2012] [Indexed: 06/02/2023]
Abstract
The use of in vitro models of complex in vivo systems has yielded many insights into the molecular mechanisms that underlie normal and pathologic physiology. However although the reduced complexity of these models is advantageous with regard to some research questions, the simplification may obscure or eliminate key influences that occur in vivo. We sought to examine this possibility with regard to the lung's response to infection, which may be inherent to resident lung cells or related to the systemic response to pulmonary infection. We used the inbred mouse strains C57BL/6J, DBA/2J, and B6.129S2-IL6(tm1Kopf), which differ in their response to inflammatory and infectious challenges, to assess in vivo responses of lung to surrogate viral and bacterial infection and compared these with responses of cultured lung slices and human A549 cells. Pulmonary cytokine concentrations were measured both after in vivo inoculation of mice and in vitro exposure of lung slices and A549 cells to surrogate viral and bacterial infections. The data indicate similarities and differences in early lung responses to in vivo compared with in vitro exposure to these inflammatory substances. Therefore, resident cells in the lung appear to respond to some challenges in a strain-independent manner, whereas some stimuli may elicit recruitment of peripheral inflammatory cells that generate the subsequent response in a genotype-related manner. These results add to the body of information pointing to host genotype as a crucial factor in mediating the severity of microbial infections and demonstrate that some of these effects may not be apparent in vitro.
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Affiliation(s)
| | | | - Michelle Randle
- Pharmacology, Southern Illinois University School of Medicine, Springfield, Illinois
| | - Sarah Barrett
- Pharmacology, Southern Illinois University School of Medicine, Springfield, Illinois
| | - Linda A Toth
- Pharmacology, Southern Illinois University School of Medicine, Springfield, Illinois
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12
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Jacobs ER, Bodiga S, Ali I, Falck AM, Falck JR, Medhora M, Dhanasekaran A. Tissue protection and endothelial cell signaling by 20-HETE analogs in intact ex vivo lung slices. Exp Cell Res 2012; 318:2143-52. [PMID: 22687879 DOI: 10.1016/j.yexcr.2012.06.005] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/16/2012] [Revised: 06/01/2012] [Accepted: 06/04/2012] [Indexed: 10/28/2022]
Abstract
The capacity to follow cell type-specific signaling in intact lung remains limited. 20-hydroxyeicosatetraenoic acid (20-HETE) is an endogenous fatty acid that mediates signaling for a number of key physiologic endpoints in the pulmonary vasculature, including cell survival and altered vascular tone. We used confocal microscopy to identify enhanced reactive oxygen species (ROS) production in endothelial cell (EC)s in intact lung evoked by two stable analogs of 20-HETE, 20-5,14-HEDE (20-hydroxyeicosa-5(Z),14(Z)-dienoic acid) and 20-5,14-HEDGE (N-[20-hydroxyeicosa-5(Z),14(Z)-dienoyl]glycine). These analogs generated increased ROS in cultured pulmonary artery endothelial cells as well. 20-HETE analog treatment decreased apoptosis of pulmonary tissue exposed to hypoxia-reoxygenation (HR) ex vivo. Enhanced ROS production and apoptosis were confirmed by biochemical assays. Our studies identify physiologically critical, graded ROS from ECs in live lung tissue ex vivo treated with 20-HETE analogs and protection from HR-induced apoptosis. These methodologies create exciting possibilities for studying signaling by stable 20-HETE analogs and other factors in pulmonary endothelial and other lung cell types in their native milieu.
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Affiliation(s)
- Elizabeth R Jacobs
- Department of Medicine, Medical College of Wisconsin, Milwaukee, WI 53226, United States.
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Ion transport by pulmonary epithelia. J Biomed Biotechnol 2011; 2011:174306. [PMID: 22131798 PMCID: PMC3205707 DOI: 10.1155/2011/174306] [Citation(s) in RCA: 101] [Impact Index Per Article: 7.8] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/01/2011] [Accepted: 08/16/2011] [Indexed: 12/13/2022] Open
Abstract
The lung surface of air-breathing vertebrates is formed by a continuous epithelium that is covered by a fluid layer. In the airways, this epithelium is largely pseudostratified consisting of diverse cell types such as ciliated cells, goblet cells, and undifferentiated basal cells, whereas the alveolar epithelium consists of alveolar type I and alveolar type II cells. Regulation and maintenance of the volume and viscosity of the fluid layer covering the epithelium is one of the most important functions of the epithelial barrier that forms the outer surface area of the lungs. Therefore, the epithelial cells are equipped with a wide variety of ion transport proteins, among which Na+, Cl−, and K+ channels have been identified to play a role in the regulation of the fluid layer. Malfunctions of pulmonary epithelial ion transport processes and, thus, impairment of the liquid balance in our lungs is associated with severe diseases, such as cystic fibrosis and pulmonary oedema. Due to the important role of pulmonary epithelial ion transport processes for proper lung function, the present paper summarizes the recent findings about composition, function, and ion transport properties of the airway epithelium as well as of the alveolar epithelium.
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Lazrak A, Jurkuvenaite A, Chen L, Keeling KM, Collawn JF, Bedwell DM, Matalon S. Enhancement of alveolar epithelial sodium channel activity with decreased cystic fibrosis transmembrane conductance regulator expression in mouse lung. Am J Physiol Lung Cell Mol Physiol 2011; 301:L557-67. [PMID: 21743028 DOI: 10.1152/ajplung.00094.2011] [Citation(s) in RCA: 43] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/11/2023] Open
Abstract
We sought to establish whether the cystic fibrosis transmembrane conductance regulator (CFTR) regulates the activity of amiloride-sensitive sodium channels (ENaC) in alveolar epithelial cells of wild-type, heterozygous (Cftr(+/-)), knockout (Cftr(-/-)), and ΔF508-expressing mice in situ. RT-PCR studies confirmed the presence of CFTR message in freshly isolated alveolar type II (ATII) cells from wild-type mice. We patched alveolar type I (ATI) and ATII cells in freshly prepared lung slices from these mice and demonstrated the presence of 4-pS ENaC channels with the following basal open probabilities (P(o)): wild-type=0.21 ± 0.015: Cftr(+/-)=0.4 ± 0.03; ΔF508=0.55 ± 0.01; and Cftr(-/-)=and 0.81 ± 0.016 (means ± SE; n ≥ 9). Forskolin (5 μM) or trypsin (2 μM), applied in the pipette solution, increased the P(o) and number of channels in ATII cells of wild-type, Cftr(+/-), and ΔF508, but not in Cftr(-/-) mice, suggesting that the latter were maximally activated. Western blot analysis showed that lungs of all groups of mice had similar levels of α-ENaC; however, lungs of Cftr(+/-) and Cftr(-/-) mice had significantly higher levels of an α-ENaC proteolytic fragment (65 kDa) that is associated with active ENaC channels. Our results indicate that ENaC activity is inversely correlated to predicted CFTR levels and that CFTR heterozygous and homozygous mice have higher levels of proteolytically processed ENaC fragments in their lungs. This is the first demonstration of functional ENaC-CFTR interactions in alveolar epithelial cells in situ.
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Affiliation(s)
- Ahmed Lazrak
- Department of Anesthesiology, School of Medicine, University of Alabama at Birmingham, 35205-3703, USA
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Sanderson MJ. Exploring lung physiology in health and disease with lung slices. Pulm Pharmacol Ther 2011; 24:452-65. [PMID: 21600999 DOI: 10.1016/j.pupt.2011.05.001] [Citation(s) in RCA: 118] [Impact Index Per Article: 9.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/13/2010] [Revised: 05/03/2011] [Accepted: 05/05/2011] [Indexed: 10/24/2022]
Abstract
The development of therapeutic approaches to treat lung disease requires an understanding of both the normal and disease physiology of the lung. Although traditional experimental approaches only address either organ or cellular physiology, the use of lung slice preparations provides a unique approach to investigate integrated physiology that links the cellular and organ responses. Living lung slices are robust and can be prepared from a variety of species, including humans, and they retain many aspects of the cellular and structural organization of the lung. Functional portions of intrapulmonary airways, arterioles and veins are present within the alveoli parenchyma. The dynamics of macroscopic changes of contraction and relaxation associated with the airways and vessels are readily observed with conventional low-magnification microscopy. The microscopic changes associated with cellular events, that determine the macroscopic responses, can be observed with confocal or two-photon microscopy. To investigate disease processes, lung slices can either be prepared from animal models of disease or animals exposed to disease invoking conditions. Alternatively, the lung slices themselves can be experimentally manipulated. Because of the ability to observe changes in cell physiology and how these responses manifest themselves at the level of the organ, lung slices have become a standard tool for the investigation of lung disease.
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Affiliation(s)
- Michael J Sanderson
- Department of Microbiology and Physiological Systems, University of Massachusetts Medical School, Worcester, MA 01655, USA.
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Wilkinson WJ, Benjamin AR, De Proost I, Orogo-Wenn MC, Yamazaki Y, Staub O, Morita T, Adriaensen D, Riccardi D, Walters DV, Kemp PJ. Alveolar epithelial CNGA1 channels mediate cGMP-stimulated, amiloride-insensitive, lung liquid absorption. Pflugers Arch 2011; 462:267-79. [PMID: 21559843 DOI: 10.1007/s00424-011-0971-0] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/18/2011] [Revised: 04/21/2011] [Accepted: 04/22/2011] [Indexed: 11/25/2022]
Abstract
Impairment of lung liquid absorption can lead to severe respiratory symptoms, such as those observed in pulmonary oedema. In the adult lung, liquid absorption is driven by cation transport through two pathways: a well-established amiloride-sensitive Na(+) channel (ENaC) and, more controversially, an amiloride-insensitive channel that may belong to the cyclic nucleotide-gated (CNG) channel family. Here, we show robust CNGA1 (but not CNGA2 or CNGA3) channel expression principally in rat alveolar type I cells; CNGA3 was expressed in ciliated airway epithelial cells. Using a rat in situ lung liquid clearance assay, CNG channel activation with 1 mM 8Br-cGMP resulted in an approximate 1.8-fold stimulation of lung liquid absorption. There was no stimulation by 8Br-cGMP when applied in the presence of either 100 μM L: -cis-diltiazem or 100 nM pseudechetoxin (PsTx), a specific inhibitor of CNGA1 channels. Channel specificity of PsTx and amiloride was confirmed by patch clamp experiments showing that CNGA1 channels in HEK 293 cells were not inhibited by 100 μM amiloride and that recombinant αβγ-ENaC were not inhibited by 100 nM PsTx. Importantly, 8Br-cGMP stimulated lung liquid absorption in situ, even in the presence of 50 μM amiloride. Furthermore, neither L: -cis-diltiazem nor PsTx affected the β(2)-adrenoceptor agonist-stimulated lung liquid absorption, but, as expected, amiloride completely ablated it. Thus, transport through alveolar CNGA1 channels, located in type I cells, underlies the amiloride-insensitive component of lung liquid reabsorption. Furthermore, our in situ data highlight the potential of CNGA1 as a novel therapeutic target for the treatment of diseases characterised by lung liquid overload.
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Affiliation(s)
- William J Wilkinson
- Division of Pathophysiology and Repair, School of Biosciences, Cardiff University, Museum Avenue, Cardiff, UK
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Han TH, Lim CJ, Choi JH, Lee SY, Ryu PD. Viability assessment of primo-node slices from organ surface primo-vascular tissues in rats. J Acupunct Meridian Stud 2011; 3:241-8. [PMID: 21185538 DOI: 10.1016/s2005-2901(10)60043-x] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/14/2010] [Accepted: 10/14/2010] [Indexed: 02/04/2023] Open
Abstract
The primo-vascular system is a novel thread-like structure which is recently rediscovered, but its cellular properties are largely unknown. In this study, a slice preparation for primo-nodes was developed to facilitate study of the cellular properties of primo-node cells in vitro. Slices (4-8 slices; 200 μm thick) were sectioned from single primo-nodes collected from the abdominal organ surface of rats and incubated in oxygenated Krebs solution at 25°C or 31°C for up to 7 hours. Trypan blue staining and whole-cell patch-clamp recordings were performed to estimate the viability of cells in the slices. Viability was largely maintained during the first 3 hours, but subsequently decreased (from 80% to 21%, p < 0.001). In addition, the viability of slices incubated at 31°C was higher than those incubated at 25°C (80%vs. 47%, p < 0.001). In whole-cell patch-clamp experiments, high resistance seals readily formed and primo-node cells showed a mean resting membrane potential (-38 mV) comparable to that recorded with sharp electrodes and outwardly-rectifying current-voltage relationships. The results show that the primo-node slices developed in this study maintained viability for up to 4 hours in vitro.
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Affiliation(s)
- Tae Hee Han
- Laboratory of Veterinary Pharmacology, College of Veterinary Medicine and Research Institute for Veterinary Science, Seoul National University, Seoul, Korea
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18
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Königshoff M, Uhl F, Gosens R. From molecule to man: integrating molecular biology with whole organ physiology in studying respiratory disease. Pulm Pharmacol Ther 2011; 24:466-70. [PMID: 21356323 DOI: 10.1016/j.pupt.2011.02.002] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/20/2010] [Revised: 02/08/2011] [Accepted: 02/21/2011] [Indexed: 11/24/2022]
Abstract
Chronic lung diseases such as asthma, chronic obstructive pulmonary disease (COPD), and idiopathic pulmonary fibrosis (IPF) are all characterized by structural changes of the airways and/or lungs that limit airflow and/or gas exchange. Currently, there is no therapy available that adequately targets the structural remodeling of the airways and lungs in these diseases. This underscores the great need for insight into the mechanisms that underpin the development of airway remodeling, fibrosis and emphysema in these diseases, in order to identify suitable drug targets. It is increasingly evident that structural cell-cell communication within the lung is central to the development of remodeling, indicating that a more integrative approach should be considered when studying molecular and cellular mechanisms of remodeling. Therefore, there is a great need to study molecular and cellular physiological and pathophysiological mechanisms in as much detail as possible, but with as little as possible loss of the physiological context. Here, we will review the use of models such as cellular co-culture, tissue culture, and lung slice culture, in which cell-cell communication and tissue architecture are better preserved or mimicked than in cell culture, and zoom in on the usefulness of molecular and cellular biological tools in these complex model systems to read out or control signaling and gene/protein regulation.
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Affiliation(s)
- Melanie Königshoff
- Comprehensive Pneumology Center, Ludwig-Maximilians-Universität and Helmholtz Zentrum München, Munich, Germany
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Shlyonsky V, Goolaerts A, Mies F, Naeije R. Electrophysiological characterization of rat type II pneumocytes in situ. Am J Respir Cell Mol Biol 2008; 39:36-44. [PMID: 18276797 DOI: 10.1165/rcmb.2007-0227oc] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022] Open
Abstract
Optimal aeration of the lungs is dependent on an alveolar fluid clearance, a process that is governed by Na+ and Cl- transport. However, the specific contribution of various ion channels in different alveolar cell types under basal or stimulated conditions is not exactly known. We established a novel functional model of rat lung slices suitable for nystatin-perforated whole-cell patch-clamp experiments. Lung slices retained a majority of live cells for up to 72 hours. Type II pneumocytes in situ had a mean capacitance of 8.8 +/- 2.5 pF and a resting membrane potential of -4.4 +/- 1.9 mV. Bath replacement of Na+ with NMDG+ decreased inward whole-cell currents by 70%, 21% and 52% of which were sensitive to 10 microM and 1 mM of amiloride, respectively. Exposure of slices to 0.5 microM dexamethasone for 1 hour did not affect ion currents, while chronic exposure (0.5 microM, 24-72 h) induced an increase in both total Na+-entry currents and amiloride-sensitive currents. Under acute exposure to 100 microM cpt-cAMP, Type II cells in situ rapidly hyperpolarized by 25-30 mV, due to activation of whole-cell Cl- currents sensitive to 0.1 mM of 5-Nitro-2-(3-phenylpropylamino)benzoic acid. In addition, in the presence of cpt-cAMP, total sodium currents and currents sensitive to 10 microM amiloride increased by 32% and 70%, respectively. Thus, in Type II pneumocytes in situ: (1) amiloride-sensitive sodium channels contribute to only half of total Na+-entry and are stimulated by chronic exposure to glucocorticoids; (2) acute increase in cellular cAMP content simultaneously stimulates the entry of Cl- and Na+ ions.
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Affiliation(s)
- Vadim Shlyonsky
- Université Libre de Bruxelles, Laboratoire de Physiologie et Physiopathologie, Campus Erasme, CP 604, 808 Route de Lennik, 1070 Bruxelles, Belgium.
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Dobbs LG, Johnson MD. Alveolar epithelial transport in the adult lung. Respir Physiol Neurobiol 2007; 159:283-300. [PMID: 17689299 DOI: 10.1016/j.resp.2007.06.011] [Citation(s) in RCA: 45] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/18/2007] [Revised: 05/31/2007] [Accepted: 06/18/2007] [Indexed: 01/11/2023]
Abstract
The alveolar surface comprises >99% of the internal surface area of the lungs. At birth, the fetal lung rapidly converts from a state of net fluid secretion, which is necessary for normal fetal lung development, to a state in which there is a minimal amount of alveolar liquid. The alveolar surface epithelium facing the air compartment is composed of TI and TII cells. The morphometric characteristics of both cell types are fairly constant over a range of mammalian species varying in body weight by a factor of approximately 50,000. From the conservation of size and shape across species, one may infer that both TI and TII cells also have important conserved functions. The regulation of alveolar ion and liquid transport has been extensively investigated using a variety of experimental models, including whole animal, isolated lung, isolated cell, and cultured cell model systems, each with their inherent strengths and weaknesses. The results obtained with different model systems and a variety of different species point to both interesting parallels and some surprising differences. Sometimes it has been difficult to reconcile results obtained with different model systems. In this section, the primary focus will be on aspects of alveolar ion and liquid transport under normal physiologic conditions, emphasizing newer data and describing evolving paradigms of lung ion and fluid transport. We will highlight some of the unanswered questions, outline the similarities and differences in results obtained with different model systems, and describe some of the complex and interweaving regulatory networks.
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Affiliation(s)
- Leland G Dobbs
- Department of Medicine, University of California San Francisco, San Francisco, CA 94118, USA.
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Foster CD, Varghese LS, Skalina RB, Gonzales LW, Guttentag SH. In vitro transdifferentiation of human fetal type II cells toward a type I-like cell. Pediatr Res 2007; 61:404-9. [PMID: 17515862 PMCID: PMC3074248 DOI: 10.1203/pdr.0b013e3180332c6d] [Citation(s) in RCA: 25] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
Abstract
For alveolar type I cells, phenotype plasticity and physiology other than gas exchange await further clarification due to in vitro study difficulties in isolating and maintaining type I cells in primary culture. Using an established in vitro model of human fetal type II cells, in which the type II phenotype is induced and maintained by adding hormones, we assessed for transdifferentiation in culture toward a type I-like cell with hormone removal for up to 144 h, followed by electron microscopy, permeability studies, and RNA and protein analysis. Hormone withdrawal resulted in diminished type II cell characteristics, including decreased microvilli, lamellar bodies, and type II cell marker RNA and protein. There was a simultaneous increase in type I characteristics, including increased epithelial cell barrier function indicative of a tight monolayer and increased type I cell marker RNA and protein. Our results indicate that hormone removal from cultured human fetal type II cells results in transdifferentiation toward a type I-like cell. This model will be useful for continued in vitro studies of human fetal alveolar epithelial cell differentiation and phenotype plasticity.
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Affiliation(s)
- Cherie D Foster
- Department of Pediatrics, University of Pennsylvania School of Medicine, The Children's Hospital of Philadelphia, Philadelphia, PA 19104, USA.
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Helms MN, Self J, Bao HF, Job LC, Jain L, Eaton DC. Dopamine activates amiloride-sensitive sodium channels in alveolar type I cells in lung slice preparations. Am J Physiol Lung Cell Mol Physiol 2006; 291:L610-8. [PMID: 16679376 DOI: 10.1152/ajplung.00426.2005] [Citation(s) in RCA: 44] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/11/2023] Open
Abstract
Active Na+ reabsorption by alveolar epithelial cells generates the driving force used to clear fluids from the air space. Using single-channel methods, we examined epithelial Na+ channel (ENaC) activity of alveolar type I (AT1) cells from live 250- to 300-microm sections of lung tissue, circumventing concerns that protracted cell isolation procedures might compromise the innate transport properties of native lung cells. We used fluorescein-labeled Erythrina crystagalli lectin to positively identify AT1 cells for single-channel patch-clamp analysis. We demonstrated, for the first time, single-channel recordings of highly selective and nonselective amiloride-sensitive ENaC channels (HSC and NSC, respectively) from AT1 cells in situ, with mean conductances of 8.2+/-2.5 and 22+/-3.2 pS, respectively. Additionally, 25 nM amiloride in the patch electrode blocked Na+ channel activity in AT1 cells. Immunohistochemical studies demonstrated the presence of dopamine D1 and D2 receptors on the surface of AT1 cells, and single-channel recordings showed that 10 microM dopamine increased Na+ channel activity [product of the number of channels and single-channel open probability (NPo)] from 0.31+/-0.19 to 0.60+/-0.21 (P<0.001). The D1 receptor antagonist SCH-23390 (10 microM) blocked the stimulatory effect of dopamine on AT1 cells, but the D2 receptor antagonist sulpiride did not.
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Affiliation(s)
- My N Helms
- Department of Physiology, The Center for Cell and Molecular Signalling, Emory University School of Medicine, Whitehead Biomedical Research Bldg., 615 Michael St., Atlanta, GA 30322, USA
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