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Eid A, Winkelmann JA, Eshein A, Taflove A, Backman V. Origins of subdiffractional contrast in optical coherence tomography. BIOMEDICAL OPTICS EXPRESS 2021; 12:3630-3642. [PMID: 34221684 PMCID: PMC8221934 DOI: 10.1364/boe.416572] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/03/2020] [Revised: 04/19/2021] [Accepted: 04/20/2021] [Indexed: 05/12/2023]
Abstract
We demonstrate that OCT images quantify subdiffractional tissue structure. Optical coherence tomography (OCT) measures stratified tissue morphology with spatial resolution limited by the temporal coherence length. Spectroscopic OCT processing, on the other hand, has enabled nanoscale sensitive analysis, presenting an unexplored question: how does subdiffractional information get folded into the OCT image and how does one best analyze to allow for unambiguous quantification of ultrastructure? We first develop an FDTD simulation to model spectral domain OCT with nanometer resolution. Using this, we validate an analytical relationship between the sample statistics through the power spectral density (PSD) of refractive index fluctuations and three measurable quantities (image mean, image variance, and spectral slope), and have found that each probes different aspects of the PSD (amplitude, integral and slope, respectively). Finally, we found that only the spectral slope, quantifying mass scaling, is monotonic with the sample autocorrelation shape.
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Affiliation(s)
- Aya Eid
- Department of Biomedical Engineering, Northwestern University, Evanston, IL 60208, USA
| | - James A. Winkelmann
- Department of Biomedical Engineering, Northwestern University, Evanston, IL 60208, USA
| | - Adam Eshein
- Department of Biomedical Engineering, Northwestern University, Evanston, IL 60208, USA
| | - Allen Taflove
- Department of Electrical Engineering, Northwestern University, Evanston, IL 60208, USA
| | - Vadim Backman
- Department of Biomedical Engineering, Northwestern University, Evanston, IL 60208, USA
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Virk RKA, Wu W, Almassalha LM, Bauer GM, Li Y, VanDerway D, Frederick J, Zhang D, Eshein A, Roy HK, Szleifer I, Backman V. Disordered chromatin packing regulates phenotypic plasticity. SCIENCE ADVANCES 2020; 6:eaax6232. [PMID: 31934628 PMCID: PMC6949045 DOI: 10.1126/sciadv.aax6232] [Citation(s) in RCA: 24] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/08/2019] [Accepted: 11/08/2019] [Indexed: 05/19/2023]
Abstract
Three-dimensional supranucleosomal chromatin packing plays a profound role in modulating gene expression by regulating transcription reactions through mechanisms such as gene accessibility, binding affinities, and molecular diffusion. Here, we use a computational model that integrates disordered chromatin packing (CP) with local macromolecular crowding (MC) to study how physical factors, including chromatin density, the scaling of chromatin packing, and the size of chromatin packing domains, influence gene expression. We computationally and experimentally identify a major role of these physical factors, specifically chromatin packing scaling, in regulating phenotypic plasticity, determining responsiveness to external stressors by influencing both intercellular transcriptional malleability and heterogeneity. Applying CPMC model predictions to transcriptional data from cancer patients, we identify an inverse relationship between patient survival and phenotypic plasticity of tumor cells.
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Affiliation(s)
- Ranya K. A. Virk
- Department of Biomedical Engineering, Northwestern University, Evanston, IL 60208, USA
| | - Wenli Wu
- Department of Biomedical Engineering, Northwestern University, Evanston, IL 60208, USA
| | - Luay M. Almassalha
- Department of Biomedical Engineering, Northwestern University, Evanston, IL 60208, USA
- Medical Scientist Training Program, Feinberg School of Medicine, Northwestern University, Chicago, IL 60211, USA
- Department of Internal Medicine, Northwestern University, Chicago, IL 60211, USA
| | - Greta M. Bauer
- Department of Biomedical Engineering, Northwestern University, Evanston, IL 60208, USA
| | - Yue Li
- Department of Biomedical Engineering, Northwestern University, Evanston, IL 60208, USA
- Applied Physics Program, Northwestern University, Evanston, IL 60208, USA
| | - David VanDerway
- Department of Biomedical Engineering, Northwestern University, Evanston, IL 60208, USA
| | - Jane Frederick
- Department of Biomedical Engineering, Northwestern University, Evanston, IL 60208, USA
| | - Di Zhang
- Department of Biomedical Engineering, Northwestern University, Evanston, IL 60208, USA
| | - Adam Eshein
- Department of Biomedical Engineering, Northwestern University, Evanston, IL 60208, USA
| | - Hemant K. Roy
- Section of Gastroenterology, Boston Medical Center/Boston University School of Medicine, Boston, MA 02118, USA
| | - Igal Szleifer
- Department of Biomedical Engineering, Northwestern University, Evanston, IL 60208, USA
- Department of Chemistry, Northwestern University, Evanston, IL 60208, USA
- Chemistry of Life Processes Institute, Northwestern University, Evanston, IL 60208, USA
- Corresponding author. (V.B.); (I.S.)
| | - Vadim Backman
- Department of Biomedical Engineering, Northwestern University, Evanston, IL 60208, USA
- Chemistry of Life Processes Institute, Northwestern University, Evanston, IL 60208, USA
- Corresponding author. (V.B.); (I.S.)
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Rozova EV, Mankovskaya IN, Belosludtseva NV, Khmil NV, Mironova GD. Uridine as a protector against hypoxia-induced lung injury. Sci Rep 2019; 9:9418. [PMID: 31263219 PMCID: PMC6602925 DOI: 10.1038/s41598-019-45979-2] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/16/2018] [Accepted: 06/20/2019] [Indexed: 11/30/2022] Open
Abstract
The effect of the activation of the mitochondrial ATP-dependent potassium channel (mitoKATP) on the ultrastructure of rat lung in acute hypoxic hypoxia (7% of oxygen in nitrogen, exposure 30 min) was studied. It was shown that uridine, a precursor of the mitoKATP activator UDP, exerted a protective effect against hypoxic damage to the lung. The administration of uridine to animals prior to hypoxia decreased the number of mitochondria with altered ultrastructure and prevented the hypoxia-induced mitochondrial swelling. Uridine also protected the epithelial, interstitial and endothelial layers of the air-blood barrier from the hypoxia-induced hyperhydration. The protective action of uridine against hypoxia-induced lung injury was eliminated by the selective blocker of mitoKATP 5-hydroxydecanoate. These data suggest that one of the mechanisms of the positive effect of uridine is related to the activation of the mitoKATP channel, which, according to the literature and our data, is involved in the protection of tissues from hypoxia and leads to adaptation to it. A possible role of uridine in the maintenance of the mitochondrial structure upon hypoxia-induced lung injury and the optimization of oxygen supply of the organism is discussed.
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Affiliation(s)
- Ekaterina V Rozova
- Bogomoletz Institute of Physiology, National Academy of Sciences of Ukraine, Bogomoletz street 4, 01024, Kiev, Ukraine
| | - Irina N Mankovskaya
- Bogomoletz Institute of Physiology, National Academy of Sciences of Ukraine, Bogomoletz street 4, 01024, Kiev, Ukraine
| | - Natalia V Belosludtseva
- Institute of Theoretical and Experimental Biophysics, Russian Academy of Sciences, Institutskaya street 3, 142290, Pushchino, Moscow region, Russia
| | - Natalya V Khmil
- Institute of Theoretical and Experimental Biophysics, Russian Academy of Sciences, Institutskaya street 3, 142290, Pushchino, Moscow region, Russia
| | - Galina D Mironova
- Institute of Theoretical and Experimental Biophysics, Russian Academy of Sciences, Institutskaya street 3, 142290, Pushchino, Moscow region, Russia.
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Ruderman S, Eshein A, Valuckaite V, Dougherty U, Almoghrabi A, Gomes A, Singh A, Pabla B, Roy HK, Hart J, Bissonnette M, Konda V, Backman V. Early increase in blood supply (EIBS) is associated with tumor risk in the Azoxymethane model of colon cancer. BMC Cancer 2018; 18:814. [PMID: 30103733 PMCID: PMC6090821 DOI: 10.1186/s12885-018-4709-7] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/02/2018] [Accepted: 07/31/2018] [Indexed: 01/20/2023] Open
Abstract
Background The present study aimed to investigate the role of blood supply in early tumorigenesis in colorectal cancer. We leveraged the renin angiotensin system (RAS) to alter colonic blood supply and determine the effect on tumor initiation and progression. Methods To test the effect of blood supply on tumorigenesis, 53 male A/J mice were randomly assigned to one of three RAS modulation groups and one of two AOM treatments. The RAS modulation groups were I) water (RAS-unmodulated) as a control group, II) angiotensin-II and III) the angiotensin receptor blocker, Losartan. The mice in each group were then randomly split into either the saline control condition or the AOM-treated condition in which tumors were induced with a standard protocol of serial azoxymethane (AOM) injections. To monitor microvascular changes in the rectal mucosa during the study, we used confocal laser endomicroscopy (CLE) with FITC-Dextran for in-vivo imaging of vessels and polarization-gated spectroscopy (PGS) to quantify rectal hemoglobin concentration ([Hb]) and blood vessel radius (BVR). Results At 12 weeks post-AOM injections and before tumor formation, CLE images revealed many traditional hallmarks of angiogenesis including vessel dilation, loss of co-planarity, irregularity, and vessel sprouting in the pericryptal capillaries of the rectal mucosa in AOM-Water tumor bearing mice. PGS measurements at the same time-point showed increased rectal [Hb] and decreased BVR. At later time points, CLE images showed pronounced angiogenic features including irregular networks throughout the colon. Notably, the AOM-Losartan mice had significantly lower tumor multiplicity and did not exhibit the same angiogenic features observed with CLE, or the increase in [Hb] or decrease in BVR measured with PGS. The AOM-AngII mice did not have any significant trends. Conclusion In-vivo PGS measurements of rectal colonic blood supply as well as CLE imaging revealed angiogenic disruptions to the capillary network prior to tumor formation. Losartan demonstrated an effective way to mitigate the changes to blood supply during tumorigenesis and reduce tumor multiplicity. These effects can be used in future studies to understand the early vessel changes observed.
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Affiliation(s)
- Sarah Ruderman
- Department of Biomedical Engineering, Northwestern University, Evanston, IL, 60208, USA
| | - Adam Eshein
- Department of Biomedical Engineering, Northwestern University, Evanston, IL, 60208, USA
| | - Vesta Valuckaite
- Center for Endoscopic Research and Therapeutics, University of Chicago Medicine, Chicago, IL, 60637, USA
| | - Urszula Dougherty
- Center for Endoscopic Research and Therapeutics, University of Chicago Medicine, Chicago, IL, 60637, USA
| | - Anas Almoghrabi
- Center for Endoscopic Research and Therapeutics, University of Chicago Medicine, Chicago, IL, 60637, USA
| | - Andrew Gomes
- Department of Biomedical Engineering, Northwestern University, Evanston, IL, 60208, USA
| | - Ajaypal Singh
- Department of Gastroenterology, Rush University, Chicago, IL, 60612, USA
| | - Baldeep Pabla
- Center for Endoscopic Research and Therapeutics, University of Chicago Medicine, Chicago, IL, 60637, USA
| | - Hemant K Roy
- Department of Gastroenterology, Boston Medical Center, Boston, MA, 02118, USA
| | - John Hart
- Center for Endoscopic Research and Therapeutics, University of Chicago Medicine, Chicago, IL, 60637, USA
| | - Marc Bissonnette
- Center for Endoscopic Research and Therapeutics, University of Chicago Medicine, Chicago, IL, 60637, USA
| | - Vani Konda
- Center for Endoscopic Research and Therapeutics, University of Chicago Medicine, Chicago, IL, 60637, USA
| | - Vadim Backman
- Department of Biomedical Engineering, Northwestern University, Evanston, IL, 60208, USA.
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Gladstein S, Stawarz A, Almassalha LM, Cherkezyan L, Chandler JE, Zhou X, Subramanian H, Backman V. Measuring Nanoscale Chromatin Heterogeneity with Partial Wave Spectroscopic Microscopy. Methods Mol Biol 2018; 1745:337-360. [PMID: 29476478 DOI: 10.1007/978-1-4939-7680-5_19] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/10/2023]
Abstract
Despite extensive research in the area, current understanding of the structural organization of higher-order chromatin topology (between 20 and 200 nm) is limited due to a lack of proper imaging techniques at these length scales. The organization of chromatin at these scales defines the physical context (nanoenvironment) in which many important biological processes occur. Improving our understanding of the nanoenvironment is crucial because it has been shown to play a critical functional role in the regulation of chemical reactions. Recent progress in partial wave spectroscopic (PWS) microscopy enables real-time measurement of higher-order chromatin organization within label-free live cells. Specifically, PWS quantifies the nanoscale variations in mass density (heterogeneity) within the cell. These advancements have made it possible to study the functional role of chromatin topology, such as its regulation of the global transcriptional state of the cell and its role in the development of cancer. In this chapter, the importance of studying chromatin topology is explained, the theory and instrumentation of PWS are described, the measurements and analysis processes for PWS are laid out in detail, and common issues, troubleshooting steps, and validation techniques are provided.
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Affiliation(s)
- Scott Gladstein
- Department of Biomedical Engineering, Northwestern University, Evanston, IL, USA
| | - Andrew Stawarz
- Department of Biomedical Engineering, Northwestern University, Evanston, IL, USA
| | - Luay M Almassalha
- Department of Biomedical Engineering, Northwestern University, Evanston, IL, USA
| | - Lusik Cherkezyan
- Department of Biomedical Engineering, Northwestern University, Evanston, IL, USA
| | - John E Chandler
- Department of Biomedical Engineering, Northwestern University, Evanston, IL, USA
| | - Xiang Zhou
- Department of Biomedical Engineering, Northwestern University, Evanston, IL, USA
| | | | - Vadim Backman
- Department of Biomedical Engineering, Northwestern University, Evanston, IL, USA.
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Almassalha LM, Bauer GM, Wu W, Cherkezyan L, Zhang D, Kendra A, Gladstein S, Chandler JE, VanDerway D, Seagle BLL, Ugolkov A, Billadeau DD, O'Halloran TV, Mazar AP, Roy HK, Szleifer I, Shahabi S, Backman V. Macrogenomic engineering via modulation of the scaling of chromatin packing density. Nat Biomed Eng 2017; 1:902-913. [PMID: 29450107 DOI: 10.1038/s41551-017-0153-2] [Citation(s) in RCA: 38] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Abstract
Many human diseases result from the dysregulation of the complex interactions between tens to thousands of genes. However, approaches for the transcriptional modulation of many genes simultaneously in a predictive manner are lacking. Here, through the combination of simulations, systems modelling and in vitro experiments, we provide a physical regulatory framework based on chromatin packing-density heterogeneity for modulating the genomic information space. Because transcriptional interactions are essentially chemical reactions, they depend largely on the local physical nanoenvironment. We show that the regulation of the chromatin nanoenvironment allows for the predictable modulation of global patterns in gene expression. In particular, we show that the rational modulation of chromatin density fluctuations can lead to a decrease in global transcriptional activity and intercellular transcriptional heterogeneity in cancer cells during chemotherapeutic responses to achieve near-complete cancer cell killing in vitro. Our findings represent a 'macrogenomic engineering' approach to modulating the physical structure of chromatin for whole-scale transcriptional modulation.
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Affiliation(s)
- Luay M Almassalha
- Department of Biomedical Engineering, Northwestern University, Evanston, IL, 60208, USA
| | - Greta M Bauer
- Department of Biomedical Engineering, Northwestern University, Evanston, IL, 60208, USA
| | - Wenli Wu
- Department of Biomedical Engineering, Northwestern University, Evanston, IL, 60208, USA
| | - Lusik Cherkezyan
- Department of Biomedical Engineering, Northwestern University, Evanston, IL, 60208, USA
| | - Di Zhang
- Department of Biomedical Engineering, Northwestern University, Evanston, IL, 60208, USA
| | - Alexis Kendra
- Department of Biomedical Engineering, Northwestern University, Evanston, IL, 60208, USA
| | - Scott Gladstein
- Department of Biomedical Engineering, Northwestern University, Evanston, IL, 60208, USA
| | - John E Chandler
- Department of Biomedical Engineering, Northwestern University, Evanston, IL, 60208, USA
| | - David VanDerway
- Department of Biomedical Engineering, Northwestern University, Evanston, IL, 60208, USA
| | - Brandon-Luke L Seagle
- Department of Obstetrics and Gynecology, Prentice Women's Hospital, Northwestern University, Feinberg School of Medicine, Chicago, IL, 60611, USA
| | - Andrey Ugolkov
- Chemistry of Life Processes Institute, Northwestern University, Evanston, IL, 60208, USA
| | - Daniel D Billadeau
- Schulze Center for Novel Therapeutics, Division of Oncology Research, Mayo Clinic, Rochester, MN, 55905, USA
| | - Thomas V O'Halloran
- Chemistry of Life Processes Institute, Northwestern University, Evanston, IL, 60208, USA.,Department of Molecular Biosciences, Northwestern University, Evanston, IL, 60208, USA.,Department of Chemistry, Northwestern University, Evanston, IL, 60208, USA
| | | | - Hemant K Roy
- Section of Gastroenterology, Boston Medical Center/Boston University School of Medicine, Boston, MA, 02118, USA
| | - Igal Szleifer
- Department of Biomedical Engineering, Northwestern University, Evanston, IL, 60208, USA. .,Chemistry of Life Processes Institute, Northwestern University, Evanston, IL, 60208, USA. .,Department of Molecular Biosciences, Northwestern University, Evanston, IL, 60208, USA.
| | - Shohreh Shahabi
- Department of Obstetrics and Gynecology, Prentice Women's Hospital, Northwestern University, Feinberg School of Medicine, Chicago, IL, 60611, USA
| | - Vadim Backman
- Department of Biomedical Engineering, Northwestern University, Evanston, IL, 60208, USA. .,Chemistry of Life Processes Institute, Northwestern University, Evanston, IL, 60208, USA.
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