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Ramlow L, Falcke M, Lindner B. An integrate-and-fire approach to Ca 2+ signaling. Part I: Renewal model. Biophys J 2023; 122:713-736. [PMID: 36635961 PMCID: PMC9989887 DOI: 10.1016/j.bpj.2023.01.007] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/19/2022] [Revised: 12/13/2022] [Accepted: 01/06/2023] [Indexed: 01/13/2023] Open
Abstract
In computational neuroscience integrate-and-fire models capture the spike generation by a subthreshold dynamics supplemented by a simple fire-and-reset rule; they allow for a numerically efficient and analytically tractable description of stochastic single cell as well as network dynamics. Stochastic spiking is also a prominent feature of Ca2+ signaling which suggests to adopt the integrate-and-fire approach for this fundamental biophysical process. The model introduced here consists of two components describing 1) activity of clusters of inositol-trisphosphate receptor channels and 2) dynamics of the global Ca2+ concentrations in the cytosol. The cluster dynamics is given in terms of a cyclic Markov chain, capturing the puff, i.e., the punctuated release of Ca2+ from intracellular stores. The cytosolic Ca2+ concentration is described by an integrate-and-fire dynamics driven by the puff current. For the cyclic Markov chain we derive expressions for the statistics of the interpuff interval, the single-puff strength and the puff current assuming constant cytosolic Ca2+. The latter condition is often well approximated because cytosolic Ca2+ varies much slower than the cluster activity does. Furthermore, because the detailed two-component model is numerically expensive to simulate and difficult to treat analytically, we develop an analytical framework to approximate the driving puff current of the stochastic cytosolic Ca2+ dynamics by a temporally uncorrelated Gaussian noise. This approximation reduces our two-component system to an integrate-and-fire model with a nonlinear drift function and a multiplicative Gaussian white noise, a model that is known to generate a renewal spike train, i.e., a point process with statistically independent interspike intervals. The model allows for fast numerical simulations, permits to derive analytical expressions for the rate of Ca2+ spiking and the coefficient of variation of the interspike interval, and to approximate the interspike interval density and the spike train power spectrum. Comparison of these statistics to experimental data is discussed.
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Affiliation(s)
- Lukas Ramlow
- Bernstein Center for Computational Neuroscience Berlin, Berlin, Germany; Physics Department of Humboldt University Berlin, Berlin, Germany.
| | - Martin Falcke
- Physics Department of Humboldt University Berlin, Berlin, Germany; Max Delbrück Center for Molecular Medicine, Berlin, Germany
| | - Benjamin Lindner
- Bernstein Center for Computational Neuroscience Berlin, Berlin, Germany; Physics Department of Humboldt University Berlin, Berlin, Germany
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2
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Sabass B. Not just a number: what cells feel depends on how they grab it. Biophys J 2022; 121:1581-1582. [PMID: 35429462 PMCID: PMC9117913 DOI: 10.1016/j.bpj.2022.04.004] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/22/2022] [Revised: 03/23/2022] [Accepted: 03/31/2022] [Indexed: 11/18/2022] Open
Affiliation(s)
- Benedikt Sabass
- Ludwig Maximilian University of Munich, 80752 Munich, Germany.
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3
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Identification of Impacted Pathways and Transcriptomic Markers as Potential Mediators of Pulmonary Fibrosis in Transgenic Mice Expressing Human IGFBP5. Int J Mol Sci 2021; 22:ijms222212609. [PMID: 34830489 PMCID: PMC8619832 DOI: 10.3390/ijms222212609] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/22/2021] [Revised: 11/15/2021] [Accepted: 11/18/2021] [Indexed: 11/16/2022] Open
Abstract
Pulmonary fibrosis is a serious disease characterized by extracellular matrix (ECM) component overproduction and remodeling. Insulin-like growth factor-binding protein 5 (IGFBP5) is a conserved member of the IGFBP family of proteins that is overexpressed in fibrotic tissues and promotes fibrosis. We used RNA sequencing (RNAseq) to identify differentially expressed genes (DEGs) between primary lung fibroblasts (pFBs) of homozygous (HOMO) transgenic mice expressing human IGFBP5 (hIGFBP5) and wild type mice (WT). The results of the differential expression analysis showed 2819 DEGs in hIGFBP5 pFBs. Functional enrichment analysis confirmed the pro-fibrotic character of IGFBP5 and revealed its impact on fundamental signaling pathways, including cytokine–cytokine receptor interaction, focal adhesion, AGE-RAGE signaling, calcium signaling, and neuroactive ligand-receptor interactions, to name a few. Noticeably, 7% of the DEGs in hIGFBP5-expressing pFBs are receptors and integrins. Furthermore, hub gene analysis revealed 12 hub genes including Fpr1, Bdkrb2, Mchr1, Nmur1, Cnr2, P2ry14, and Ptger3. Validation assays were performed to complement the RNAseq data. They confirmed significant differences in the levels of the corresponding proteins in cultured pFBs. Our study provides new insights into the molecular mechanism(s) of IGFBP5-associated pulmonary fibrosis through possible receptor interactions that drive fibrosis and tissue remodeling.
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McDonough RC, Price C. Targeted Activation of GPCR-Mediated Ca 2+ Signaling Drives Enhanced Cartilage-Like Matrix Formation. Tissue Eng Part A 2021; 28:405-419. [PMID: 34693731 PMCID: PMC9271335 DOI: 10.1089/ten.tea.2021.0078] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/24/2023] Open
Abstract
Intracellular calcium ([Ca2+]i) signaling is a critical regulator of chondrogenesis, chondrocyte differentiation, and cartilage development. Calcium (Ca2+) signaling is known to direct processes that govern chondrocyte gene expression, protein synthesis, cytoskeletal remodeling, and cell fate. Control of chondrocyte/chondroprogenitor Ca2+ signaling has been attempted through mechanical and/or pharmacological activation of endogenous Ca2+ signaling transducers; however, such approaches can lack specificity and/or precision regarding Ca2+ activation mechanisms. Synthetic signaling platforms permitting precise and selective Ca2+ signal transduction can improve dissection of the roles that [Ca2+]i signaling play in chondrocyte behavior. One such platform is the chemogenetic hM3Dq DREADD (designer receptor exclusively activated by designer drugs) that activates [Ca2+]i signaling via the Gαq-PLCβ-IP3-ER pathway upon clozapine N-oxide (CNO) administration. We previously demonstrated hM3Dq's ability to precisely and synthetically initiate robust [Ca2+]i transients and oscillatory [Ca2+]i signaling in chondrocyte-like ATDC5 cells. Here, we investigate the effects that long-term CNO stimulatory culture have on hM3Dq [Ca2+]i signaling dynamics, proliferation, and protein deposition in 2D ATDC5 cultures. Long-term culturing under repeated CNO stimulation modified the temporal dynamics of hM3Dq [Ca2+]i signaling, increased cell proliferation, and enhanced matrix production in a CNO dose- and frequency-dependent manner, and triggered the formation of cell condensations that developed aligned, anisotropic neotissue structures rich in cartilaginous proteoglycans and collagens, all in the absence of differentiation inducers. This study demonstrated Gαq-GPCR-mediated [Ca2+]i signaling involvement in chondroprogenitor proliferation and cartilage-like matrix production, and established hM3Dq as a powerful tool for elucidating the role of GPCR-mediated Ca2+ signaling in chondrogenesis and chondrocyte differentiation.
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Affiliation(s)
- Ryan C McDonough
- University of Delaware, 5972, Biomedical Engineering, 161 Colburn Lab, Newark, Delaware, United States, 19716-5600;
| | - Christopher Price
- University of Delaware, 5972, Biomedical Engineering, Newark, Delaware, United States;
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5
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Roy Choudhury A, Großhans J, Kong D. Ion Channels in Epithelial Dynamics and Morphogenesis. Cells 2021; 10:cells10092280. [PMID: 34571929 PMCID: PMC8465836 DOI: 10.3390/cells10092280] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/28/2021] [Revised: 08/22/2021] [Accepted: 08/30/2021] [Indexed: 01/21/2023] Open
Abstract
Mechanosensitive ion channels mediate the neuronal sensation of mechanical signals such as sound, touch, and pain. Recent studies point to a function of these channel proteins in cell types and tissues in addition to the nervous system, such as epithelia, where they have been little studied, and their role has remained elusive. Dynamic epithelia are intrinsically exposed to mechanical forces. A response to pull and push is assumed to constitute an essential part of morphogenetic movements of epithelial tissues, for example. Mechano-gated channels may participate in sensing and responding to such forces. In this review, focusing on Drosophila, we highlight recent results that will guide further investigations concerned with the mechanistic role of these ion channels in epithelial cells.
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Hachim MY, Elemam NM, Ramakrishnan RK, Bajbouj K, Olivenstein R, Hachim IY, Al Heialy S, Hamid Q, Busch H, Hamoudi R. Wnt Signaling Is Deranged in Asthmatic Bronchial Epithelium and Fibroblasts. Front Cell Dev Biol 2021; 9:641404. [PMID: 33791298 PMCID: PMC8006921 DOI: 10.3389/fcell.2021.641404] [Citation(s) in RCA: 13] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/14/2020] [Accepted: 02/01/2021] [Indexed: 12/16/2022] Open
Abstract
Both canonical and non-canonical Wnt signaling pathway alterations have been documented in pulmonary disease pathogenesis and progression; therefore, they can be an attractive target for pharmaceutical management of severe asthma. Wnt/β-catenin signaling was shown to link early embryonic lung development impairment to later in life asthmatic airway remodeling. Here we explored the changes in Wnt signaling associated with asthma initiation and progression in epithelial and fibroblasts using a comprehensive approach based on in silico analysis and followed by in vitro validation. In summary, the in silico analysis showed that the bronchial epithelium of severe asthmatic patients showed a deranged balance between Wnt enhancer and Wnt inhibitors. A Th2-high phenotype is associated with upregulated Wnt-negative regulators, while inflammatory and neutrophilic severe asthmatics showed higher canonical Wnt signaling member enrichment. Most of these genes are regulators of healthy lung development early in life and, if disturbed, can make people susceptible to developing asthma early in life and prone to developing a severe phenotype. Most of the Wnt members are secreted, and their effect can be in an autocrine fashion on the bronchial epithelium, paracrine on nearby adjacent structural cells like fibroblasts and smooth muscles, or systemic in blood. Our results showed that canonical Wnt signaling is needed for the proper response of cells to proliferative stimuli, which puts cells under stress. Cells in response to this proliferative stress will activate the senescence mechanism, which is also dependent on Wnt signaling. Inhibition of Wnt signaling using FH535 inhibits both proliferation and senescence markers in bronchial fibroblasts compared to DMSO-treated cells. In fibroblasts from asthmatic patients, inhibition of Wnt signaling did not show that effect as the Wnt signaling is deranged besides other pathways that might be non-functional.
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Affiliation(s)
- Mahmood Yaseen Hachim
- College of Medicine, Mohammed bin Rashid University of Medicine and Health Sciences, Dubai, United Arab Emirates
| | - Noha Mousaad Elemam
- Sharjah Institute for Medical Research, College of Medicine, University of Sharjah, Sharjah, United Arab Emirates
| | - Rakhee K Ramakrishnan
- Sharjah Institute for Medical Research, College of Medicine, University of Sharjah, Sharjah, United Arab Emirates
| | - Khuloud Bajbouj
- Sharjah Institute for Medical Research, College of Medicine, University of Sharjah, Sharjah, United Arab Emirates
| | | | - Ibrahim Yaseen Hachim
- Sharjah Institute for Medical Research, College of Medicine, University of Sharjah, Sharjah, United Arab Emirates
| | - Saba Al Heialy
- College of Medicine, Mohammed bin Rashid University of Medicine and Health Sciences, Dubai, United Arab Emirates.,Meakins-Christie Laboratories, McGill University, Montreal, QC, Canada
| | - Qutayba Hamid
- Sharjah Institute for Medical Research, College of Medicine, University of Sharjah, Sharjah, United Arab Emirates.,Meakins-Christie Laboratories, McGill University, Montreal, QC, Canada
| | - Hauke Busch
- Medical Systems Biology Group, Institute for Experimental Dermatology, Institute for Cardiogenetics, University of Lübeck, Lübeck, Germany
| | - Rifat Hamoudi
- Sharjah Institute for Medical Research, College of Medicine, University of Sharjah, Sharjah, United Arab Emirates.,Division of Surgery and Interventional Science, University College London, London, United Kingdom
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7
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Wan L, Jiang D, Correa-Gallegos D, Ramesh P, Zhao J, Ye H, Zhu S, Wannemacher J, Volz T, Rinkevich Y. Connexin43 gap junction drives fascia mobilization and repair of deep skin wounds. Matrix Biol 2021; 97:58-71. [PMID: 33508427 DOI: 10.1016/j.matbio.2021.01.005] [Citation(s) in RCA: 25] [Impact Index Per Article: 8.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/22/2020] [Revised: 01/19/2021] [Accepted: 01/19/2021] [Indexed: 12/23/2022]
Abstract
Deep and voluminous skin wounds are repaired with scars, by mobilization of fibroblasts and extracellular matrix from fascia, deep below the skin. The molecular trigger of this novel repair mechanism is incompletely understood. Here we reveal that the gap junction alpha-1 protein (Connexin43, Cx43) is the key to patch repair of deep wounds. By combining full-thickness wound models with fibroblast lineage specific transgenic lines, we show Cx43 expression is substantially upregulated in specialized fibroblasts of the fascia deep beneath the skin that are responsible for scar formation. Using live imaging of fascia fibroblasts and fate tracing of the fascia extracellular matrix we show that Cx43 inhibition disrupts calcium oscillations in cultured fibroblasts and that this inhibits collective migration of fascia EPFs necessary to mobilize fascia matrix into open wounds. Cell-cell communication through Cx43 thus mediates matrix movement and scar formation, and is necessary for patch repair of voluminous wounds. These mechanistic findings have broad clinical implications toward treating fibrosis, aggravated scarring and impaired wound healing.
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Affiliation(s)
- Li Wan
- Helmholtz Zentrum München, Institute of Lung Biology and Disease, Comprehensive Pneumology Center, Munich, Germany
| | - Dongsheng Jiang
- Helmholtz Zentrum München, Institute of Lung Biology and Disease, Comprehensive Pneumology Center, Munich, Germany
| | - Donovan Correa-Gallegos
- Helmholtz Zentrum München, Institute of Lung Biology and Disease, Comprehensive Pneumology Center, Munich, Germany
| | - Pushkar Ramesh
- Helmholtz Zentrum München, Institute of Lung Biology and Disease, Comprehensive Pneumology Center, Munich, Germany
| | - Jiakuan Zhao
- Helmholtz Zentrum München, Institute of Lung Biology and Disease, Comprehensive Pneumology Center, Munich, Germany
| | - Haifeng Ye
- Helmholtz Zentrum München, Institute of Lung Biology and Disease, Comprehensive Pneumology Center, Munich, Germany
| | - Shaohua Zhu
- Helmholtz Zentrum München, Institute of Lung Biology and Disease, Comprehensive Pneumology Center, Munich, Germany
| | - Juliane Wannemacher
- Helmholtz Zentrum München, Institute of Lung Biology and Disease, Comprehensive Pneumology Center, Munich, Germany
| | - Thomas Volz
- Technical University of Munich, School of Medicine, Klinikum rechts der Isar, Department of Dermatology and Allergology, Munich, Germany
| | - Yuval Rinkevich
- Helmholtz Zentrum München, Institute of Lung Biology and Disease, Comprehensive Pneumology Center, Munich, Germany; Helmholtz Zentrum München, Institute of Regenerative Biology and Medicine, Munich, Germany.
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8
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Franklin JM, Ghosh RP, Shi Q, Reddick MP, Liphardt JT. Concerted localization-resets precede YAP-dependent transcription. Nat Commun 2020; 11:4581. [PMID: 32917893 PMCID: PMC7486942 DOI: 10.1038/s41467-020-18368-x] [Citation(s) in RCA: 28] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/27/2019] [Accepted: 07/13/2020] [Indexed: 02/07/2023] Open
Abstract
Yes-associated protein 1 (YAP) is a transcriptional regulator with critical roles in mechanotransduction, organ size control, and regeneration. Here, using advanced tools for real-time visualization of native YAP and target gene transcription dynamics, we show that a cycle of fast exodus of nuclear YAP to the cytoplasm followed by fast reentry to the nucleus ("localization-resets") activates YAP target genes. These "resets" are induced by calcium signaling, modulation of actomyosin contractility, or mitosis. Using nascent-transcription reporter knock-ins of YAP target genes, we show a strict association between these resets and downstream transcription. Oncogenically-transformed cell lines lack localization-resets and instead show dramatically elevated rates of nucleocytoplasmic shuttling of YAP, suggesting an escape from compartmentalization-based control. The single-cell localization and transcription traces suggest that YAP activity is not a simple linear function of nuclear enrichment and point to a model of transcriptional activation based on nucleocytoplasmic exchange properties of YAP.
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Affiliation(s)
- J Matthew Franklin
- Bioengineering, Stanford University, Stanford, CA, 94305, USA
- BioX Institute, Stanford University, Stanford, CA, 94305, USA
- ChEM-H, Stanford University, Stanford, CA, 94305, USA
- Cell Biology Division, Stanford Cancer Institute, Stanford, CA, 94305, USA
- Chemical Engineering, Stanford University, Stanford, CA, 94305, USA
| | - Rajarshi P Ghosh
- Bioengineering, Stanford University, Stanford, CA, 94305, USA.
- BioX Institute, Stanford University, Stanford, CA, 94305, USA.
- ChEM-H, Stanford University, Stanford, CA, 94305, USA.
- Cell Biology Division, Stanford Cancer Institute, Stanford, CA, 94305, USA.
| | - Quanming Shi
- Bioengineering, Stanford University, Stanford, CA, 94305, USA
- BioX Institute, Stanford University, Stanford, CA, 94305, USA
- ChEM-H, Stanford University, Stanford, CA, 94305, USA
- Cell Biology Division, Stanford Cancer Institute, Stanford, CA, 94305, USA
| | - Michael P Reddick
- Bioengineering, Stanford University, Stanford, CA, 94305, USA
- BioX Institute, Stanford University, Stanford, CA, 94305, USA
- ChEM-H, Stanford University, Stanford, CA, 94305, USA
- Cell Biology Division, Stanford Cancer Institute, Stanford, CA, 94305, USA
- Chemical Engineering, Stanford University, Stanford, CA, 94305, USA
| | - Jan T Liphardt
- Bioengineering, Stanford University, Stanford, CA, 94305, USA.
- BioX Institute, Stanford University, Stanford, CA, 94305, USA.
- ChEM-H, Stanford University, Stanford, CA, 94305, USA.
- Cell Biology Division, Stanford Cancer Institute, Stanford, CA, 94305, USA.
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9
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Ghilardi SJ, O'Reilly BM, Sgro AE. Intracellular signaling dynamics and their role in coordinating tissue repair. WILEY INTERDISCIPLINARY REVIEWS. SYSTEMS BIOLOGY AND MEDICINE 2020; 12:e1479. [PMID: 32035001 PMCID: PMC7187325 DOI: 10.1002/wsbm.1479] [Citation(s) in RCA: 22] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 09/16/2019] [Revised: 12/20/2019] [Accepted: 12/31/2019] [Indexed: 12/11/2022]
Abstract
Tissue repair is a complex process that requires effective communication and coordination between cells across multiple tissues and organ systems. Two of the initial intracellular signals that encode injury signals and initiate tissue repair responses are calcium and extracellular signal-regulated kinase (ERK). However, calcium and ERK signaling control a variety of cellular behaviors important for injury repair including cellular motility, contractility, and proliferation, as well as the activity of several different transcription factors, making it challenging to relate specific injury signals to their respective repair programs. This knowledge gap ultimately hinders the development of new wound healing therapies that could take advantage of native cellular signaling programs to more effectively repair tissue damage. The objective of this review is to highlight the roles of calcium and ERK signaling dynamics as mechanisms that link specific injury signals to specific cellular repair programs during epithelial and stromal injury repair. We detail how the signaling networks controlling calcium and ERK can now also be dissected using classical signal processing techniques with the advent of new biosensors and optogenetic signal controllers. Finally, we advocate the importance of recognizing calcium and ERK dynamics as key links between injury detection and injury repair programs that both organize and execute a coordinated tissue repair response between cells across different tissues and organs. This article is categorized under: Models of Systems Properties and Processes > Mechanistic Models Biological Mechanisms > Cell Signaling Laboratory Methods and Technologies > Imaging Models of Systems Properties and Processes > Organ, Tissue, and Physiological Models.
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Affiliation(s)
- Samuel J. Ghilardi
- Department of Biomedical Engineering and the Biological Design CenterBoston UniversityBostonMassachusetts
| | - Breanna M. O'Reilly
- Department of Biomedical Engineering and the Biological Design CenterBoston UniversityBostonMassachusetts
| | - Allyson E. Sgro
- Department of Biomedical Engineering and the Biological Design CenterBoston UniversityBostonMassachusetts
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10
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do Amaral JB, Bloise AC, França CN, Perez-Novo C, Machado-Santelli GM, Alencar AM, Pezato R. Alterations in cellular force parameters and cell projections in Nasal polyps-derived fibroblasts. Auris Nasus Larynx 2019; 47:98-104. [PMID: 31272842 DOI: 10.1016/j.anl.2019.06.007] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/06/2019] [Revised: 06/07/2019] [Accepted: 06/20/2019] [Indexed: 02/03/2023]
Abstract
OBJECTIVE Chronic Rhinosinusitis with Nasal Polyps (CRSwNP) is a disease that features a mechanical dysfunction involving chronic inflammation and altered tissue remodeling. In this study, we aim to evaluate the fibroblast morphology and its cellular traction force in primary fibroblasts cell cultures obtained from both healthy individuals (n=7) and patients with CRSwNP (n=8). METHODS Using a Traction-force Microscopy we analyzed parameters of Force/Tension in fibroblasts cultures in both experimental groups. RESULTS The analysis of the Projected Area of Cell revealed that fibroblasts derived from nasal mucosa of healthy individuals have an area on average 39.24% larger than the fibroblasts obtained from the nasal polyp tissue. We also observed that the parameters directly related to the force of the cell, Max Cumulative Force and Net Contractile Moment, presented a high Force/Tension per unit of area in the fibroblasts derived from the healthy nasal mucosa (on average 41% and 52.54% higher than the fibroblasts of the nasal polyp respectively). CONCLUSION Our results demonstrate a cellular mechanism that may be associated with the mechanical dysfunction found in the Nasal Polyp tissue. The weak traction force of nasal polyp-derived fibroblast may, in lower dimensions, impact on the remodeling of nasal mucosa in CRSwNP.
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Affiliation(s)
- Jônatas Bussador do Amaral
- ENT Research Lab., Department of Otorhinolaryngology - Head and Neck Surgery, Federal University of Sao Paulo, Rua Coronel Lisboa, 958, Vila Clementino, São Paulo, SP, 04020-041, Brazil.
| | - Antonio Carlos Bloise
- Institute of Physics, University of Sao Paulo, Rua do Matão, Travessa R Número 187, Cidade Universitária, São Paulo, SP 05508-090, Brazil
| | - Carolina Nunes França
- Universidade Santo Amaro, Pós Graduação em Ciências da Saúde, Rua Enéas de Siqueira Neto, 340 Jardim das Imbuias, São Paulo, SP 04829-300, Brazil
| | - Claudina Perez-Novo
- Laboratory of Proteinchemistry, Proteomics and Epigenetic Signalling Department of Biomedical Sciences, Campus Drie Eiken, building T, first floor Universiteitsplein 1 2610 Wilrijk University of Antwerp, Belgium
| | - Gláucia Maria Machado-Santelli
- Department of Cell and Developmental Biology, Institute of Biomedical Sciences, University of Sao Paulo, Avenida Prof Lineu Prestes, 1524, dade Universitária, Sao Paulo, SP 05508-900, Brazil
| | - Adriano Mesquita Alencar
- Institute of Physics, University of Sao Paulo, Rua do Matão, Travessa R Número 187, Cidade Universitária, São Paulo, SP 05508-090, Brazil
| | - Rogério Pezato
- ENT Research Lab., Department of Otorhinolaryngology - Head and Neck Surgery, Federal University of Sao Paulo, Rua Coronel Lisboa, 958, Vila Clementino, São Paulo, SP, 04020-041, Brazil
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Alert R, Casademunt J. Role of Substrate Stiffness in Tissue Spreading: Wetting Transition and Tissue Durotaxis. LANGMUIR : THE ACS JOURNAL OF SURFACES AND COLLOIDS 2019; 35:7571-7577. [PMID: 30281318 DOI: 10.1021/acs.langmuir.8b02037] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/13/2023]
Abstract
Living tissues undergo wetting transitions: On a surface, they can either form a dropletlike cell aggregate or spread as a monolayer of migrating cells. Tissue wetting depends not only on the chemical but also on the mechanical properties of the substrate. Here, we study the role of substrate stiffness in tissue spreading, which we describe by means of an active polar fluid model. Taking into account that cells exert larger active traction forces on stiffer substrates, we predict a tissue wetting transition at a critical substrate stiffness that decreases with tissue size. On substrates with a stiffness gradient, we find that the tissue spreads faster on the stiffer side. Furthermore, we show that the tissue can wet the substrate on the stiffer side while dewetting from the softer side. We also show that, by means of viscous forces transmitted across the tissue, the stiffer-side interface can transiently drag the softer-side interface toward increasing stiffness, against its spreading tendency. These two effects result in directed tissue migration up the stiffness gradient. This phenomenon-tissue durotaxis-can thus emerge both from dewetting on the soft side and from hydrodynamic interactions between the tissue interfaces. Overall, our work unveils mechanisms whereby substrate stiffness impacts the collective migration and the active wetting properties of living tissues, which are relevant in development, regeneration, and cancer.
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12
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Calcium Oscillatory Behavior and Its Possible Role during Wound Healing in Bovine Corneal Endothelial Cells in Culture. BIOMED RESEARCH INTERNATIONAL 2019; 2019:8647121. [PMID: 30915363 PMCID: PMC6409003 DOI: 10.1155/2019/8647121] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 08/22/2018] [Revised: 01/29/2019] [Accepted: 02/06/2019] [Indexed: 12/29/2022]
Abstract
In epithelial layers in culture, immediately after an injury a fast calcium wave (FCW) propagates from the wound borders toward the rest of the monolayer. We show here that similarly to other tissues, during the FCW in bovine corneal endothelial (BCE) cells in culture many cells exhibit calcium oscillations mediated by IP3 signaling. In this study we perform a detailed characterization of this oscillatory behavior and explore its possible role in the process of wound healing. In previous work we showed that, in BCE cells in culture, the healing cells undergo two stages of caspase-dependent apoptosis, at approximately two and eight hours after wounding. We determined that inhibition of the FCW greatly increases the apoptotic rate of the two stages, suggesting that the wave prevents excessive apoptosis of the healing cells. Taking this into account, we investigated the possible participation of the calcium oscillations during the FCW in apoptosis of the healing cells. For this, we employed ARL-67156 (ARL), a weak competitive inhibitor of ecto-ATPases, and the calcium chelator EGTA. We show here that, in healing BCE cells, ARL enhances cellular calcium oscillations during the FCW, while EGTA decreases oscillations. We found that ARL produces a significant decrease (to about half the control value) in the apoptotic index of the first stage of apoptosis, while EGTA increases it. Neither drug noticeably affects the second stage. We have interpreted the effect of ARL on apoptosis as due to the maintenance of moderately risen ATP levels during the FCW, which is in turn the cause for the enhancement of ATP-dependent calcium oscillations. Correspondingly, EGTA would increase the apoptotic index of the first stage by promoting a decrease in the calcium oscillatory rate. The fact that the second stage of apoptosis is not affected by the drugs suggests that the two stages are at least partially subject to different signaling pathways.
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13
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Huang Y, Schell C, Huber TB, Şimşek AN, Hersch N, Merkel R, Gompper G, Sabass B. Traction force microscopy with optimized regularization and automated Bayesian parameter selection for comparing cells. Sci Rep 2019; 9:539. [PMID: 30679578 PMCID: PMC6345967 DOI: 10.1038/s41598-018-36896-x] [Citation(s) in RCA: 25] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/14/2018] [Accepted: 11/27/2018] [Indexed: 12/12/2022] Open
Abstract
Adherent cells exert traction forces on to their environment which allows them to migrate, to maintain tissue integrity, and to form complex multicellular structures during developmental morphogenesis. Traction force microscopy (TFM) enables the measurement of traction forces on an elastic substrate and thereby provides quantitative information on cellular mechanics in a perturbation-free fashion. In TFM, traction is usually calculated via the solution of a linear system, which is complicated by undersampled input data, acquisition noise, and large condition numbers for some methods. Therefore, standard TFM algorithms either employ data filtering or regularization. However, these approaches require a manual selection of filter- or regularization parameters and consequently exhibit a substantial degree of subjectiveness. This shortcoming is particularly serious when cells in different conditions are to be compared because optimal noise suppression needs to be adapted for every situation, which invariably results in systematic errors. Here, we systematically test the performance of new methods from computer vision and Bayesian inference for solving the inverse problem in TFM. We compare two classical schemes, L1- and L2-regularization, with three previously untested schemes, namely Elastic Net regularization, Proximal Gradient Lasso, and Proximal Gradient Elastic Net. Overall, we find that Elastic Net regularization, which combines L1 and L2 regularization, outperforms all other methods with regard to accuracy of traction reconstruction. Next, we develop two methods, Bayesian L2 regularization and Advanced Bayesian L2 regularization, for automatic, optimal L2 regularization. Using artificial data and experimental data, we show that these methods enable robust reconstruction of traction without requiring a difficult selection of regularization parameters specifically for each data set. Thus, Bayesian methods can mitigate the considerable uncertainty inherent in comparing cellular tractions in different conditions.
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Affiliation(s)
- Yunfei Huang
- Theoretical Soft Matter and Biophysics, Institute of Complex Systems-2 and Institute for Advanced Simulation, Forschungszentrum Juelich, D-52425, Juelich, Germany
| | - Christoph Schell
- Institut für Klinische Pathologie, Universitätsklinikum Freiburg, D-79002, Freiburg, Germany.,Berta-Ottenstein Programme, Faculty of Medicine, University of Freiburg, Freiburg, D-79106, Germany
| | - Tobias B Huber
- Department of Medicine IV, Faculty of Medicine, Medical Center - University of Freiburg, Freiburg, Germany.,BIOSS Center for Biological Signalling Studies, Albert-Ludwigs-University Freiburg, Freiburg, Germany.,III. Department of Medicine, University Medical Center Hamburg-Eppendorf, Hamburg, Germany
| | - Ahmet Nihat Şimşek
- Theoretical Soft Matter and Biophysics, Institute of Complex Systems-2 and Institute for Advanced Simulation, Forschungszentrum Juelich, D-52425, Juelich, Germany
| | - Nils Hersch
- Biomechanics, Institute of Complex Systems-7, Forschungszentrum Juelich, D-52425, Juelich, Germany
| | - Rudolf Merkel
- Biomechanics, Institute of Complex Systems-7, Forschungszentrum Juelich, D-52425, Juelich, Germany
| | - Gerhard Gompper
- Theoretical Soft Matter and Biophysics, Institute of Complex Systems-2 and Institute for Advanced Simulation, Forschungszentrum Juelich, D-52425, Juelich, Germany
| | - Benedikt Sabass
- Theoretical Soft Matter and Biophysics, Institute of Complex Systems-2 and Institute for Advanced Simulation, Forschungszentrum Juelich, D-52425, Juelich, Germany.
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14
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Lembong J, Lerman MJ, Kingsbury TJ, Civin CI, Fisher JP. A Fluidic Culture Platform for Spatially Patterned Cell Growth, Differentiation, and Cocultures. Tissue Eng Part A 2018; 24:1715-1732. [PMID: 29845891 PMCID: PMC6302678 DOI: 10.1089/ten.tea.2018.0020] [Citation(s) in RCA: 26] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/19/2018] [Accepted: 05/24/2018] [Indexed: 01/09/2023] Open
Abstract
Stem cell cultures within perfusion bioreactors, while efficient in obtaining cell numbers, often lack the similarity to native tissues and consequently cell phenotype. We develop a three-dimensional (3D)-printed fluidic chamber for dynamic stem cell culture, with emphasis on control over flow and substrate curvature in a 3D environment, two physiologic features of native tissues. The chamber geometry, consisting of an array of vertical cylindrical pillars, facilitates actin-mediated localization of human mesenchymal stem cells (hMSCs) within ∼200 μm distance from the pillars, enabling spatial patterning of hMSCs and endothelial cells in cocultures and subsequent modulation of calcium signaling between these two essential cell types in the bone marrow microenvironment. Flow-enhanced osteogenic differentiation of hMSCs in growth media imposes spatial variations of alkaline phosphatase expression, which positively correlates with local shear stress. Proliferation of hMSCs is maintained within the chamber, exceeding the cell expansion in conventional static culture. The capability to manipulate cell spatial patterning, differentiation, and 3D tissue formation through geometry and flow demonstrates the culture chamber's relevant chemomechanical cues in stem cell microenvironments, thus providing an easy-to-implement tool to study interactions among substrate curvature, shear stress, and intracellular actin machinery in the tissue-engineered construct.
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Affiliation(s)
- Josephine Lembong
- Fischell Department of Bioengineering, University of Maryland, College Park, Maryland
- NIH Center for Engineering Complex Tissues, University of Maryland, College Park, Maryland
| | - Max J. Lerman
- NIH Center for Engineering Complex Tissues, University of Maryland, College Park, Maryland
- Department of Materials Science and Engineering, University of Maryland, College Park, Maryland
- Surface and Trace Chemical Analysis Group, Materials Measurement Lab, National Institute of Standards and Technology, Gaithersburg, Maryland
| | - Tami J. Kingsbury
- Department of Physiology, University of Maryland School of Medicine, Baltimore, Maryland
- Center for Stem Cell Biology & Regenerative Medicine, University of Maryland School of Medicine, Baltimore, Maryland
| | - Curt I. Civin
- Department of Physiology, University of Maryland School of Medicine, Baltimore, Maryland
- Department of Pediatrics, University of Maryland School of Medicine, Baltimore, Maryland
- Center for Stem Cell Biology & Regenerative Medicine, University of Maryland School of Medicine, Baltimore, Maryland
| | - John P. Fisher
- Fischell Department of Bioengineering, University of Maryland, College Park, Maryland
- NIH Center for Engineering Complex Tissues, University of Maryland, College Park, Maryland
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15
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Mugler A, Sun B. Special issue on emergent collective behaviour from groups of cells. Phys Biol 2018; 15:060202. [PMID: 30109858 DOI: 10.1088/1478-3975/aad3a1] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/27/2023]
Affiliation(s)
- Andrew Mugler
- Department of Physics and Astronomy, Purdue University, West Lafayette, IN 47907, United States of America
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16
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Falcke M, Friedhoff VN. The stretch to stray on time: Resonant length of random walks in a transient. CHAOS (WOODBURY, N.Y.) 2018; 28:053117. [PMID: 29857685 DOI: 10.1063/1.5023164] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/08/2023]
Abstract
First-passage times in random walks have a vast number of diverse applications in physics, chemistry, biology, and finance. In general, environmental conditions for a stochastic process are not constant on the time scale of the average first-passage time or control might be applied to reduce noise. We investigate moments of the first-passage time distribution under an exponential transient describing relaxation of environmental conditions. We solve the Laplace-transformed (generalized) master equation analytically using a novel method that is applicable to general state schemes. The first-passage time from one end to the other of a linear chain of states is our application for the solutions. The dependence of its average on the relaxation rate obeys a power law for slow transients. The exponent ν depends on the chain length N like ν=-N/(N+1) to leading order. Slow transients substantially reduce the noise of first-passage times expressed as the coefficient of variation (CV), even if the average first-passage time is much longer than the transient. The CV has a pronounced minimum for some lengths, which we call resonant lengths. These results also suggest a simple and efficient noise control strategy and are closely related to the timing of repetitive excitations, coherence resonance, and information transmission by noisy excitable systems. A resonant number of steps from the inhibited state to the excitation threshold and slow recovery from negative feedback provide optimal timing noise reduction and information transmission.
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Affiliation(s)
- Martin Falcke
- Max Delbrück Center for Molecular Medicine, Robert Rössle Str. 10, 13125 Berlin, Germany
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