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Tripathi M, Sharma A, Sinharay S, Raichur AM. Effect of PVP Molecular Weights on the Synthesis of Ultrasmall Cus Nanoflakes: Synthesis, Properties, and Potential Application for Phototheranostics. ACS Appl Bio Mater 2024; 7:1671-1681. [PMID: 38447193 DOI: 10.1021/acsabm.3c01123] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 03/08/2024]
Abstract
Copper sulfide nanoparticles (CuS) hold tremendous potential for applications in photothermal therapy (PTT) and photoacoustic imaging (PAI). However, the conventional chemical coprecipitation method often leads to particle agglomeration issues. To overcome this challenge, we utilized polyvinylpyrrolidone (PVP) as a stabilizing agent, resulting in the synthesis of small PVP-CuS nanoparticles named PC10, PCK30, and PC40. Our study aimed to investigate how different molecular weights of PVP influence the nanoparticles' crystalline characteristics and essential properties, especially their photoacoustic and photothermal responses. While prior research on PVP-assisted CuS nanoparticles has been conducted, our study delves deeper into this area, providing insights into optical properties. Remarkably, all synthesized nanoparticles exhibited a crystalline structure, were smaller than 10 nm, and featured an absorbance peak at 1020 nm, indicating their robust photoacoustic and photothermal capabilities. Among these nanoparticles, PC10 emerged as the standout performer, displaying superior photoacoustic properties. Our photothermal experiments demonstrated significant temperature increases in all cases, with PC10 achieving an impressive efficiency of 51%. Moreover, cytotoxicity assays revealed the nanoparticles' compatibility with cells, coupled with an enhanced incidence of apoptosis compared to necrosis. These findings underscore the promising potential of PVP-stabilized CuS nanoparticles for advanced cancer theranostics.
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Affiliation(s)
- Madhavi Tripathi
- Department of Materials Engineering, Indian Institute of Science, Bangalore 560012, India
| | - Ananya Sharma
- Centre for Biosystems Science and Engineering, Indian Institute of Science, Bangalore 560012, India
| | - Sanhita Sinharay
- Centre for Biosystems Science and Engineering, Indian Institute of Science, Bangalore 560012, India
| | - Ashok M Raichur
- Department of Materials Engineering, Indian Institute of Science, Bangalore 560012, India
- College of Science, Engineering and Technology, University of South Africa, Florida, Johannesburg 1709, South Africa
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2
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Knopf P, Stowbur D, Hoffmann SHL, Hermann N, Maurer A, Bucher V, Poxleitner M, Tako B, Sonanini D, Krishnamachary B, Sinharay S, Fehrenbacher B, Gonzalez-Menendez I, Reckmann F, Bomze D, Flatz L, Kramer D, Schaller M, Forchhammer S, Bhujwalla ZM, Quintanilla-Martinez L, Schulze-Osthoff K, Pagel MD, Fransen MF, Röcken M, Martins AF, Pichler BJ, Ghoreschi K, Kneilling M. Acidosis-mediated increase in IFN-γ-induced PD-L1 expression on cancer cells as an immune escape mechanism in solid tumors. Mol Cancer 2023; 22:207. [PMID: 38102680 PMCID: PMC10722725 DOI: 10.1186/s12943-023-01900-0] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/14/2023] [Accepted: 11/12/2023] [Indexed: 12/17/2023] Open
Abstract
Immune checkpoint inhibitors have revolutionized cancer therapy, yet the efficacy of these treatments is often limited by the heterogeneous and hypoxic tumor microenvironment (TME) of solid tumors. In the TME, programmed death-ligand 1 (PD-L1) expression on cancer cells is mainly regulated by Interferon-gamma (IFN-γ), which induces T cell exhaustion and enables tumor immune evasion. In this study, we demonstrate that acidosis, a common characteristic of solid tumors, significantly increases IFN-γ-induced PD-L1 expression on aggressive cancer cells, thus promoting immune escape. Using preclinical models, we found that acidosis enhances the genomic expression and phosphorylation of signal transducer and activator of transcription 1 (STAT1), and the translation of STAT1 mRNA by eukaryotic initiation factor 4F (elF4F), resulting in an increased PD-L1 expression. We observed this effect in murine and human anti-PD-L1-responsive tumor cell lines, but not in anti-PD-L1-nonresponsive tumor cell lines. In vivo studies fully validated our in vitro findings and revealed that neutralizing the acidic extracellular tumor pH by sodium bicarbonate treatment suppresses IFN-γ-induced PD-L1 expression and promotes immune cell infiltration in responsive tumors and thus reduces tumor growth. However, this effect was not observed in anti-PD-L1-nonresponsive tumors. In vivo experiments in tumor-bearing IFN-γ-/- mice validated the dependency on immune cell-derived IFN-γ for acidosis-mediated cancer cell PD-L1 induction and tumor immune escape. Thus, acidosis and IFN-γ-induced elevation of PD-L1 expression on cancer cells represent a previously unknown immune escape mechanism that may serve as a novel biomarker for anti-PD-L1/PD-1 treatment response. These findings have important implications for the development of new strategies to enhance the efficacy of immunotherapy in cancer patients.
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Affiliation(s)
- Philipp Knopf
- Werner Siemens Imaging Center, Department of Preclinical Imaging and Radiopharmacy, Eberhard Karls University, Tübingen, Germany
| | - Dimitri Stowbur
- Werner Siemens Imaging Center, Department of Preclinical Imaging and Radiopharmacy, Eberhard Karls University, Tübingen, Germany
- Cluster of Excellence iFIT (EXC 2180) "Image Guided and Functionally Instructed Tumor Therapies", Röntgenweg 13, 72076, Tübingen, Germany
| | - Sabrina H L Hoffmann
- Werner Siemens Imaging Center, Department of Preclinical Imaging and Radiopharmacy, Eberhard Karls University, Tübingen, Germany
| | - Natalie Hermann
- Werner Siemens Imaging Center, Department of Preclinical Imaging and Radiopharmacy, Eberhard Karls University, Tübingen, Germany
| | - Andreas Maurer
- Werner Siemens Imaging Center, Department of Preclinical Imaging and Radiopharmacy, Eberhard Karls University, Tübingen, Germany
- Cluster of Excellence iFIT (EXC 2180) "Image Guided and Functionally Instructed Tumor Therapies", Röntgenweg 13, 72076, Tübingen, Germany
| | - Valentina Bucher
- Werner Siemens Imaging Center, Department of Preclinical Imaging and Radiopharmacy, Eberhard Karls University, Tübingen, Germany
| | - Marilena Poxleitner
- Werner Siemens Imaging Center, Department of Preclinical Imaging and Radiopharmacy, Eberhard Karls University, Tübingen, Germany
| | - Bredi Tako
- Werner Siemens Imaging Center, Department of Preclinical Imaging and Radiopharmacy, Eberhard Karls University, Tübingen, Germany
| | - Dominik Sonanini
- Werner Siemens Imaging Center, Department of Preclinical Imaging and Radiopharmacy, Eberhard Karls University, Tübingen, Germany
- Cluster of Excellence iFIT (EXC 2180) "Image Guided and Functionally Instructed Tumor Therapies", Röntgenweg 13, 72076, Tübingen, Germany
| | - Balaji Krishnamachary
- Division of Cancer Imaging Research, The Russell H Morgan Department of Radiology and Radiological Science, The Johns Hopkins University School of Medicine, Baltimore, MD, USA
| | - Sanhita Sinharay
- Department of Cancer Systems Imaging, MD Anderson Cancer Center, 1881 East Rd, Houston, TX, 77054, USA
| | | | - Irene Gonzalez-Menendez
- Cluster of Excellence iFIT (EXC 2180) "Image Guided and Functionally Instructed Tumor Therapies", Röntgenweg 13, 72076, Tübingen, Germany
- Institute of Pathology and Neuropathology, Department of Pathology, Eberhard Karls University of Tübingen and Comprehensive Cancer Center, Tübingen University Hospital, Tübingen, Germany
| | - Felix Reckmann
- Werner Siemens Imaging Center, Department of Preclinical Imaging and Radiopharmacy, Eberhard Karls University, Tübingen, Germany
| | - David Bomze
- Department of Dermatology, Tel-Aviv Medical Center, Tel-Aviv, Israel
| | - Lukas Flatz
- Department of Dermatology, Eberhard Karls University, Tübingen, Germany
| | - Daniela Kramer
- Interfaculty Institute of Biochemistry, Eberhard Karls University, Tübingen, Germany
| | - Martin Schaller
- Department of Dermatology, Eberhard Karls University, Tübingen, Germany
| | | | - Zaver M Bhujwalla
- Division of Cancer Imaging Research, The Russell H Morgan Department of Radiology and Radiological Science, The Johns Hopkins University School of Medicine, Baltimore, MD, USA
- Sidney Kimmel Comprehensive Cancer Center, The Johns Hopkins University, School of Medicine, Baltimore, MD, USA
- Department of Radiation Oncology and Molecular Radiation Sciences, The Johns Hopkins University, School of Medicine, Baltimore, MD, USA
| | - Leticia Quintanilla-Martinez
- Cluster of Excellence iFIT (EXC 2180) "Image Guided and Functionally Instructed Tumor Therapies", Röntgenweg 13, 72076, Tübingen, Germany
- Institute of Pathology and Neuropathology, Department of Pathology, Eberhard Karls University of Tübingen and Comprehensive Cancer Center, Tübingen University Hospital, Tübingen, Germany
| | - Klaus Schulze-Osthoff
- Cluster of Excellence iFIT (EXC 2180) "Image Guided and Functionally Instructed Tumor Therapies", Röntgenweg 13, 72076, Tübingen, Germany
- Interfaculty Institute of Biochemistry, Eberhard Karls University, Tübingen, Germany
- German Cancer Consortium (DKTK), partner site Tübingen, German Cancer Research Center (DKFZ), Im Neuenheimer Feld 280, 69120, Heidelberg, Germany
| | - Mark D Pagel
- Department of Cancer Systems Imaging, MD Anderson Cancer Center, 1881 East Rd, Houston, TX, 77054, USA
| | - Marieke F Fransen
- Department of Immunohematology and Blood Transfusion, Leiden University Medical Center (LUMC), Leiden, Netherlands
| | - Martin Röcken
- Cluster of Excellence iFIT (EXC 2180) "Image Guided and Functionally Instructed Tumor Therapies", Röntgenweg 13, 72076, Tübingen, Germany
- Department of Dermatology, Eberhard Karls University, Tübingen, Germany
- German Cancer Consortium (DKTK), partner site Tübingen, German Cancer Research Center (DKFZ), Im Neuenheimer Feld 280, 69120, Heidelberg, Germany
| | - André F Martins
- Werner Siemens Imaging Center, Department of Preclinical Imaging and Radiopharmacy, Eberhard Karls University, Tübingen, Germany
- Cluster of Excellence iFIT (EXC 2180) "Image Guided and Functionally Instructed Tumor Therapies", Röntgenweg 13, 72076, Tübingen, Germany
- German Cancer Consortium (DKTK), partner site Tübingen, German Cancer Research Center (DKFZ), Im Neuenheimer Feld 280, 69120, Heidelberg, Germany
| | - Bernd J Pichler
- Werner Siemens Imaging Center, Department of Preclinical Imaging and Radiopharmacy, Eberhard Karls University, Tübingen, Germany
- Cluster of Excellence iFIT (EXC 2180) "Image Guided and Functionally Instructed Tumor Therapies", Röntgenweg 13, 72076, Tübingen, Germany
- German Cancer Consortium (DKTK), partner site Tübingen, German Cancer Research Center (DKFZ), Im Neuenheimer Feld 280, 69120, Heidelberg, Germany
| | - Kamran Ghoreschi
- Department of Dermatology, Venereology and Allergology, Charité - Universitätsmedizin Berlin, Corporate Member of Freie Universität Berlin, Humboldt-Universität zu Berlin, Berlin Institute of Health, 10117, Berlin, Germany
| | - Manfred Kneilling
- Werner Siemens Imaging Center, Department of Preclinical Imaging and Radiopharmacy, Eberhard Karls University, Tübingen, Germany.
- Cluster of Excellence iFIT (EXC 2180) "Image Guided and Functionally Instructed Tumor Therapies", Röntgenweg 13, 72076, Tübingen, Germany.
- Department of Dermatology, Eberhard Karls University, Tübingen, Germany.
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Patkulkar P, Subbalakshmi AR, Jolly MK, Sinharay S. Mapping Spatiotemporal Heterogeneity in Tumor Profiles by Integrating High-Throughput Imaging and Omics Analysis. ACS Omega 2023; 8:6126-6138. [PMID: 36844580 PMCID: PMC9948167 DOI: 10.1021/acsomega.2c06659] [Citation(s) in RCA: 4] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/16/2022] [Accepted: 01/05/2023] [Indexed: 05/14/2023]
Abstract
Intratumoral heterogeneity associates with more aggressive disease progression and worse patient outcomes. Understanding the reasons enabling the emergence of such heterogeneity remains incomplete, which restricts our ability to manage it from a therapeutic perspective. Technological advancements such as high-throughput molecular imaging, single-cell omics, and spatial transcriptomics allow recording of patterns of spatiotemporal heterogeneity in a longitudinal manner, thus offering insights into the multiscale dynamics of its evolution. Here, we review the latest technological trends and biological insights from molecular diagnostics as well as spatial transcriptomics, both of which have witnessed burgeoning growth in the recent past in terms of mapping heterogeneity within tumor cell types as well as the stromal constitution. We also discuss ongoing challenges, indicating possible ways to integrate insights across these methods to have a systems-level spatiotemporal map of heterogeneity in each tumor and a more systematic investigation of the implications of heterogeneity for patient outcomes.
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Martinez-Orengo N, Tahmazian S, Lai J, Wang Z, Sinharay S, Schreiber-Stainthorp W, Basuli F, Maric D, Reid W, Shah S, Hammoud DA. Assessing organ-level immunoreactivity in a rat model of sepsis using TSPO PET imaging. Front Immunol 2022; 13:1010263. [PMID: 36439175 PMCID: PMC9685400 DOI: 10.3389/fimmu.2022.1010263] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/02/2022] [Accepted: 10/17/2022] [Indexed: 11/11/2022] Open
Abstract
There is current need for new approaches to assess/measure organ-level immunoreactivity and ensuing dysfunction in systemic inflammatory response syndrome (SIRS) and sepsis, in order to protect or recover organ function. Using a rat model of systemic sterile inflammatory shock (intravenous LPS administration), we performed PET imaging with a translocator protein (TSPO) tracer, [18F]DPA-714, as a biomarker for reactive immunoreactive changes in the brain and peripheral organs. In vivo dynamic PET/CT scans showed increased [18F]DPA-714 binding in the brain, lungs, liver and bone marrow, 4 hours after LPS injection. Post-LPS mean standard uptake values (SUVmean) at equilibrium were significantly higher in those organs compared to baseline. Changes in spleen [18F]DPA-714 binding were variable but generally decreased after LPS. SUVmean values in all organs, except the spleen, positively correlated with several serum cytokines/chemokines. In vitro measures of TSPO expression and immunofluorescent staining validated the imaging results. Noninvasive molecular imaging with [18F]DPA-714 PET in a rat model of systemic sterile inflammatory shock, along with in vitro measures of TSPO expression, showed brain, liver and lung inflammation, spleen monocytic efflux/lymphocytic activation and suggested increased bone marrow hematopoiesis. TSPO PET imaging can potentially be used to quantify SIRS and sepsis-associated organ-level immunoreactivity and assess the effectiveness of therapeutic and preventative approaches for associated organ failures, in vivo.
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Affiliation(s)
- Neysha Martinez-Orengo
- Center for Infectious Disease Imaging, Radiology and Imaging Sciences, Clinical Center, National Institutes of Health, Bethesda, MD, United States
| | - Sarine Tahmazian
- Center for Infectious Disease Imaging, Radiology and Imaging Sciences, Clinical Center, National Institutes of Health, Bethesda, MD, United States
| | - Jianhao Lai
- Center for Infectious Disease Imaging, Radiology and Imaging Sciences, Clinical Center, National Institutes of Health, Bethesda, MD, United States
| | - Zeping Wang
- Center for Infectious Disease Imaging, Radiology and Imaging Sciences, Clinical Center, National Institutes of Health, Bethesda, MD, United States
| | - Sanhita Sinharay
- Center for Infectious Disease Imaging, Radiology and Imaging Sciences, Clinical Center, National Institutes of Health, Bethesda, MD, United States
| | - William Schreiber-Stainthorp
- Center for Infectious Disease Imaging, Radiology and Imaging Sciences, Clinical Center, National Institutes of Health, Bethesda, MD, United States
| | - Falguni Basuli
- Chemistry and Synthesis Center, National Heart, Lung, and Blood Institute, National Institutes of Health, Rockville, MD, United States
| | - Dragan Maric
- Flow and Imaging Cytometry Core Facility, National Institute of Neurological Disorders and Stroke, National Institutes of Health, Bethesda, MD, United States
| | - William Reid
- Center for Infectious Disease Imaging, Radiology and Imaging Sciences, Clinical Center, National Institutes of Health, Bethesda, MD, United States
| | - Swati Shah
- Center for Infectious Disease Imaging, Radiology and Imaging Sciences, Clinical Center, National Institutes of Health, Bethesda, MD, United States
| | - Dima A. Hammoud
- Center for Infectious Disease Imaging, Radiology and Imaging Sciences, Clinical Center, National Institutes of Health, Bethesda, MD, United States
- *Correspondence: Dima A. Hammoud,
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5
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Shah S, Sinharay S, Patel R, Solomon J, Lee JH, Schreiber-Stainthorp W, Basuli F, Zhang X, Hagen KR, Reeder R, Wakim P, Huzella LM, Maric D, Johnson RF, Hammoud DA. PET imaging of TSPO expression in immune cells can assess organ-level pathophysiology in high-consequence viral infections. Proc Natl Acad Sci U S A 2022; 119:e2110846119. [PMID: 35385353 PMCID: PMC9169664 DOI: 10.1073/pnas.2110846119] [Citation(s) in RCA: 6] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/14/2021] [Accepted: 02/10/2022] [Indexed: 01/08/2023] Open
Abstract
Ebola virus (EBOV) disease is characterized by lymphopenia, breach in vascular integrity, cytokine storm, and multiorgan failure. The pathophysiology of organ involvement, however, is incompletely understood. Using [18F]-DPA-714 positron emission tomography (PET) imaging targeting the translocator protein (TSPO), an immune cell marker, we sought to characterize the progression of EBOV-associated organ-level pathophysiology in the EBOV Rhesus macaque model. Dynamic [18F]-DPA-714 PET/computed tomography imaging was performed longitudinally at baseline and at multiple time points after EBOV inoculation, and distribution volumes (Vt) were calculated as a measure of peripheral TSPO binding. Using a mixed-effect linear regression model, spleen and lung Vt decreased, while the bone marrow Vt increased over time after infection. No clear trend was found for liver Vt. Multiple plasma cytokines correlated negatively with lung/spleen Vt and positively with bone marrow Vt. Multiplex immunofluorescence staining in spleen and lung sections confirmed organ-level lymphoid and monocytic loss/apoptosis, thus validating the imaging results. Our findings are consistent with EBOV-induced progressive monocytic and lymphocytic depletion in the spleen, rather than immune activation, as well as depletion of alveolar macrophages in the lungs, with inefficient reactive neutrophilic activation. Increased bone marrow Vt, on the other hand, suggests hematopoietic activation in response to systemic immune cell depletion and leukocytosis and could have prognostic relevance. In vivo PET imaging provided better understanding of organ-level pathophysiology during EBOV infection. A similar approach can be used to delineate the pathophysiology of other systemic infections and to evaluate the effectiveness of newly developed treatment and vaccine strategies.
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Affiliation(s)
- Swati Shah
- Center for Infectious Disease Imaging, Radiology and Imaging Sciences, Clinical Center, NIH, Bethesda, MD 20892
| | - Sanhita Sinharay
- Center for Infectious Disease Imaging, Radiology and Imaging Sciences, Clinical Center, NIH, Bethesda, MD 20892
| | - Reema Patel
- Center for Infectious Disease Imaging, Radiology and Imaging Sciences, Clinical Center, NIH, Bethesda, MD 20892
| | - Jeffrey Solomon
- Clinical Monitoring Research Program Directorate, Frederick National Laboratory for Cancer Research, National Cancer Institute, Frederick, MD 21702
| | - Ji Hyun Lee
- Integrated Research Facility, National Institute of Allergy and Infectious Diseases, NIH, Frederick, MD 21702
| | | | - Falguni Basuli
- Chemistry and Synthesis Center, National Heart, Lung, and Blood Institute, NIH, Rockville, MD 20824
| | - Xiang Zhang
- Chemistry and Synthesis Center, National Heart, Lung, and Blood Institute, NIH, Rockville, MD 20824
| | - Katie R. Hagen
- Integrated Research Facility, National Institute of Allergy and Infectious Diseases, NIH, Frederick, MD 21702
| | - Rebecca Reeder
- Integrated Research Facility, National Institute of Allergy and Infectious Diseases, NIH, Frederick, MD 21702
| | - Paul Wakim
- Biostatistics and Clinical Epidemiology Service, Clinical Center, NIH, Bethesda, MD 20892
| | - Louis M. Huzella
- Integrated Research Facility, National Institute of Allergy and Infectious Diseases, NIH, Frederick, MD 21702
| | - Dragan Maric
- Flow and Imaging Cytometry Core Facility, National Institute of Neurological Disorders and Stroke, NIH, Bethesda, MD 20892
| | - Reed F. Johnson
- Emerging Viral Pathogens Section, National Institute of Allergy and Infectious Diseases, NIH, Frederick, MD 21702
| | - Dima A. Hammoud
- Center for Infectious Disease Imaging, Radiology and Imaging Sciences, Clinical Center, NIH, Bethesda, MD 20892
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Sinharay S, Srinivasula S, Schreiber-Stainthorp W, Shah S, Degrange P, Bonvillain A, Wang J, Dodd L, Carrasquillo JA, Hammoud DA, Di Mascio M. Monitoring Immune Activation with Whole-Body Fluorodeoxyglucose-Positron-Emission Tomography in Simian Immunodeficiency Virus-Infected Rhesus Macaques. Immunohorizons 2021; 5:557-567. [PMID: 34282030 DOI: 10.4049/immunohorizons.2100043] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/16/2021] [Accepted: 06/16/2021] [Indexed: 11/19/2022] Open
Abstract
This study aimed to assess immune activation in tissues by measuring glucose metabolism with 18F-fluorodeoxyglucose (FDG) and investigate the associations of various peripheral markers of disease progression with initiation and interruption of combination antiretroviral therapy in SIV-infected rhesus macaques (Macaca mulatta). Mixed-effect linear models revealed a significant inverse association of peripheral blood CD4+ T cell counts (p < 0.01) and a direct association of plasma viral load (p < 0.01) with the FDG uptake in the spleen, bone marrow, and most clusters of lymph nodes. In contrast, no significant associations were found for the liver and the bowel FDG uptake. We also found no association of the fraction of proliferating peripheral blood T and B lymphocytes with FDG uptake in any analyzed tissues. The bowel FDG uptake of uninfected animals was heterogeneous and reached levels as high as those seen in the bowel or the clusters of lymph nodes or the spleen of high viremic SIV-infected animals, suggesting that factors beyond SIV-induced immune activation dominate the gut FDG uptake.
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Affiliation(s)
- Sanhita Sinharay
- Center for Infectious Disease Imaging, Radiology and Imaging Sciences, Clinical Center, National Institutes of Health, Bethesda, MD
| | - Sharat Srinivasula
- AIDS Imaging Research Section, Clinical Monitoring Research Program Directorate, AIDS Imaging Research Section, Frederick National Laboratory for Cancer Research, Frederick, MD
| | - William Schreiber-Stainthorp
- Center for Infectious Disease Imaging, Radiology and Imaging Sciences, Clinical Center, National Institutes of Health, Bethesda, MD
| | - Swati Shah
- Center for Infectious Disease Imaging, Radiology and Imaging Sciences, Clinical Center, National Institutes of Health, Bethesda, MD
| | - Paula Degrange
- AIDS Imaging Research Section, Integrated Research Facility, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Frederick, MD
| | - Andrew Bonvillain
- AIDS Imaging Research Section, Integrated Research Facility, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Frederick, MD
| | - Jing Wang
- AIDS Imaging Research Section, Clinical Monitoring Research Program Directorate, AIDS Imaging Research Section, Frederick National Laboratory for Cancer Research, Frederick, MD
| | - Lori Dodd
- Biostatistics Research Branch, Division of Clinical Research, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Rockville, MD
| | - Jorge A Carrasquillo
- Molecular Imaging Branch, Center for Cancer Research, National Cancer Institute, National Institutes of Health, Bethesda, MD; and
| | - Dima A Hammoud
- Center for Infectious Disease Imaging, Radiology and Imaging Sciences, Clinical Center, National Institutes of Health, Bethesda, MD
| | - Michele Di Mascio
- AIDS Imaging Research Section, Division of Clinical Research, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Bethesda, MD
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7
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Sinharay S, Tu TW, Kovacs ZI, Schreiber-Stainthorp W, Sundby M, Zhang X, Papadakis GZ, Reid WC, Frank JA, Hammoud DA. In vivo imaging of sterile microglial activation in rat brain after disrupting the blood-brain barrier with pulsed focused ultrasound: [18F]DPA-714 PET study. J Neuroinflammation 2019; 16:155. [PMID: 31345243 PMCID: PMC6657093 DOI: 10.1186/s12974-019-1543-z] [Citation(s) in RCA: 36] [Impact Index Per Article: 7.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/27/2019] [Accepted: 07/09/2019] [Indexed: 12/26/2022] Open
Abstract
Background Magnetic resonance imaging (MRI)-guided pulsed focused ultrasound combined with the infusion of microbubbles (pFUS+MB) induces transient blood-brain barrier opening (BBBO) in targeted regions. pFUS+MB, through the facilitation of neurotherapeutics’ delivery, has been advocated as an adjuvant treatment for neurodegenerative diseases and malignancies. Sterile neuroinflammation has been recently described following pFUS+MB BBBO. In this study, we used PET imaging with [18F]-DPA714, a biomarker of translocator protein (TSPO), to assess for neuroinflammatory changes following single and multiple pFUS+MB sessions. Methods Three groups of Sprague-Dawley female rats received MRI-guided pFUS+MB (Optison™; 5–8 × 107 MB/rat) treatments to the left frontal cortex and right hippocampus. Group A rats were sonicated once. Group B rats were sonicated twice and group C rats were sonicated six times on weekly basis. Passive cavitation detection feedback (PCD) controlled the peak negative pressure during sonication. We performed T1-weighted scans immediately after sonication to assess efficiency of BBBO and T2*-weighted scans to evaluate for hypointense voxels. [18F]DPA-714 PET/CT scans were acquired after the BBB had closed, 24 h after sonication in group A and within an average of 10 days from the last sonication in groups B and C. Ratios of T1 enhancement, T2* values, and [18F]DPA-714 percent injected dose/cc (%ID/cc) values in the targeted areas to the contralateral brain were calculated. Histological assessment for microglial activation/astrocytosis was performed. Results In all groups, [18F]DPA-714 binding was increased at the sonicated compared to non-sonicated brain (%ID/cc ratios > 1). Immunohistopathology showed increased staining for microglial and astrocytic markers in the sonicated frontal cortex compared to contralateral brain and to a lesser extent in the sonicated hippocampus. Using MRI, we documented BBB disruption immediately after sonication with resolution of BBBO 24 h later. We found more T2* hypointense voxels with increasing number of sonications. In a longitudinal group of animals imaged after two and after six sonications, there was no cumulative increase of neuroinflammation on PET. Conclusion Using [18F]DPA-714 PET, we documented in vivo neuroinflammatory changes in association with pFUS+MB. Our protocol (utilizing PCD feedback to minimize damage) resulted in neuroinflammation visualized 24 h post one sonication. Our findings were supported by immunohistochemistry showing microglial activation and astrocytosis. Experimental sonication parameters intended for BBB disruption should be evaluated for neuroinflammatory sequelae prior to implementation in clinical trials. Electronic supplementary material The online version of this article (10.1186/s12974-019-1543-z) contains supplementary material, which is available to authorized users.
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Affiliation(s)
- Sanhita Sinharay
- Hammoud Laboratory, Center for Infectious Disease Imaging, Clinical Center, National Institutes of Health, 10 Center Drive, Building 10, Room 1C-368, Bethesda, MD, 20892, USA.,University of Texas, MD Anderson Cancer Center, Houston, USA
| | - Tsang-Wei Tu
- Frank Laboratory, Radiology and Imaging Sciences, Clinical Center, National Institutes of Health, Bethesda, MD, USA.,Center for Neuroscience and Regenerative Medicine, Uniformed Services University of the Health Sciences, Bethesda, MD, USA.,Department of Radiology, Howard University, Washington DC, USA
| | - Zsofia I Kovacs
- Frank Laboratory, Radiology and Imaging Sciences, Clinical Center, National Institutes of Health, Bethesda, MD, USA.,Institute for Biomedical Engineering, Swiss Federal Institute of Technology, Zurich, Switzerland
| | - William Schreiber-Stainthorp
- Hammoud Laboratory, Center for Infectious Disease Imaging, Clinical Center, National Institutes of Health, 10 Center Drive, Building 10, Room 1C-368, Bethesda, MD, 20892, USA
| | - Maggie Sundby
- Frank Laboratory, Radiology and Imaging Sciences, Clinical Center, National Institutes of Health, Bethesda, MD, USA
| | - Xiang Zhang
- Imaging Probe Development Center, National Heart, Lung, and Blood Institute, National Institutes of Health, Rockville, MD, USA
| | - Georgios Z Papadakis
- Hammoud Laboratory, Center for Infectious Disease Imaging, Clinical Center, National Institutes of Health, 10 Center Drive, Building 10, Room 1C-368, Bethesda, MD, 20892, USA.,Department of Radiology, University of Crete and Department of Medical Imaging Heraklion University Hospital, Crete, Greece
| | - William C Reid
- Hammoud Laboratory, Center for Infectious Disease Imaging, Clinical Center, National Institutes of Health, 10 Center Drive, Building 10, Room 1C-368, Bethesda, MD, 20892, USA
| | - Joseph A Frank
- Frank Laboratory, Radiology and Imaging Sciences, Clinical Center, National Institutes of Health, Bethesda, MD, USA.,National Institute of Biomedical Imaging and Bioengineering, National Institutes of Health, Bethesda, MD, USA
| | - Dima A Hammoud
- Hammoud Laboratory, Center for Infectious Disease Imaging, Clinical Center, National Institutes of Health, 10 Center Drive, Building 10, Room 1C-368, Bethesda, MD, 20892, USA.
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Heiss JD, Lungu C, Hammoud DA, Herscovitch P, Ehrlich DJ, Argersinger DP, Sinharay S, Scott G, Wu T, Federoff HJ, Zaghloul KA, Hallett M, Lonser RR, Bankiewicz KS. Trial of magnetic resonance-guided putaminal gene therapy for advanced Parkinson's disease. Mov Disord 2019; 34:1073-1078. [PMID: 31145831 DOI: 10.1002/mds.27724] [Citation(s) in RCA: 53] [Impact Index Per Article: 10.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/22/2019] [Revised: 04/26/2019] [Accepted: 05/06/2019] [Indexed: 01/08/2023] Open
Abstract
OBJECTIVE To investigate the safety and tolerability of convection-enhanced delivery of an adeno-associated virus, serotype-2 vector carrying glial cell line-derived neurotrophic factor into the bilateral putamina of PD patients. METHODS Thirteen adult patients with advanced PD underwent adeno-associated virus, serotype-2 vector carrying glial cell line-derived neurotrophic factor and gadoteridol (surrogate MRI tracer) coinfusion (450 μL/hemisphere) at escalating doses: 9 × 1010 vg (n = 6); 3 × 1011 vg (n = 6); and 9 × 1011 vg (n = 1). Intraoperative MRI monitored infusion distribution. Patients underwent UPDRS assessment and [18 F]FDOPA-PET scanning preoperatively and 6 and 18 months postoperatively. RESULTS Adeno-associated virus, serotype-2 vector carrying glial cell line-derived neurotrophic factor was tolerated without clinical or radiographic toxicity. Average putaminal coverage was 26%. UPDRS scores remained stable. Ten of thirteen and 12 of 13 patients had increased [18 F]FDOPA Kis at 6 and 18 months postinfusion (increase range: 5-274% and 8-130%; median, 36% and 54%), respectively. Ki differences between baseline and 6- and 18-month follow-up were statistically significant (P < 0.0002). CONCLUSION Adeno-associated virus, serotype-2 vector carrying glial cell line-derived neurotrophic factor infusion was safe and well tolerated. Increased [18 F]FDOPA uptake suggests a neurotrophic effect on dopaminergic neurons. © 2019 International Parkinson and Movement Disorder Society.
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Affiliation(s)
- John D Heiss
- Surgical Neurology Branch, National Institute of Neurological Disorders and Stroke, National Institutes of Health, Bethesda, Maryland, USA
| | - Codrin Lungu
- Division of Clinical Research, and Office of the Clinical Director, National Institute of Neurological Disorders and Stroke, National Institutes of Health, Bethesda, Maryland, USA
| | - Dima A Hammoud
- Radiology and Imaging Sciences, Clinical Center, National Institutes of Health, Bethesda, Maryland, USA
| | - Peter Herscovitch
- Positron Emission Tomography Department, Clinical Center, National Institutes of Health, Bethesda, Maryland, USA
| | - Debra J Ehrlich
- Parkinson's Disease Clinic, Office of the Clinical Director, National Institute of Neurological Disorders and Stroke, National Institutes of Health, Bethesda, Maryland, USA
| | - Davis P Argersinger
- Surgical Neurology Branch, National Institute of Neurological Disorders and Stroke, National Institutes of Health, Bethesda, Maryland, USA
| | - Sanhita Sinharay
- Radiology and Imaging Sciences, Clinical Center, National Institutes of Health, Bethesda, Maryland, USA
| | - Gretchen Scott
- Surgical Neurology Branch, National Institute of Neurological Disorders and Stroke, National Institutes of Health, Bethesda, Maryland, USA
| | - Tianxia Wu
- Clinical Trials Unit, National Institute of Neurological Disorders and Stroke, National Institutes of Health, Bethesda, Maryland, USA
| | - Howard J Federoff
- Department of Neurology, University of California-Irvine, Irvine, California, USA
| | - Kareem A Zaghloul
- Surgical Neurology Branch, National Institute of Neurological Disorders and Stroke, National Institutes of Health, Bethesda, Maryland, USA
| | - Mark Hallett
- Human Motor Control Section, Medical Neurology Branch, National Institute of Neurological Disorders and Stroke, National Institutes of Health, Bethesda, Maryland, USA
| | - Russell R Lonser
- Department of Neurological Surgery, The Ohio State University Wexner Medical Center, Columbus, Ohio, USA
| | - Krystof S Bankiewicz
- Department of Neurological Surgery, The Ohio State University Wexner Medical Center, Columbus, Ohio, USA.,Department of Neurological Surgery, University of California-San Francisco, San Francisco, California, USA
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Sinharay S, Randtke EA, Howison CM, Ignatenko NA, Pagel MD. Detection of Enzyme Activity and Inhibition during Studies in Solution, In Vitro and In Vivo with CatalyCEST MRI. Mol Imaging Biol 2019; 20:240-248. [PMID: 28726131 DOI: 10.1007/s11307-017-1092-8] [Citation(s) in RCA: 19] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/27/2023]
Abstract
PURPOSE The detection of enzyme activities and evaluation of enzyme inhibitors have been challenging with magnetic resonance imaging (MRI). To address this need, we have developed a diamagnetic, nonmetallic contrast agent and a protocol known as catalyCEST MRI that uses chemical exchange saturation transfer (CEST) to detect enzyme activity as well as enzyme inhibition. PROCEDURES We synthesized a diamagnetic MRI contrast agent that has enzyme responsive and enzyme unresponsive CEST signals. We tested the ability of this agent to detect the activity of kallikrein 6 (KLK6) in biochemical solutions, in vitro and in vivo, with and without a KLK6 inhibitor. RESULTS The agent detected KLK6 activity in solution and also detected KLK6 inhibition by antithrombin III. KLK6 activity was detected during in vitro studies with HCT116 colon cancer cells, relative to the detection of almost no activity in a KLK6-knockdown HCT116 cell line and HCT116 cells treated with antithrombin III inhibitor. Finally, strong enzyme activity was detected within an in vivo HCT116 tumor model, while lower enzyme activity was detected in a KLK6 knockdown tumor model and in the HCT116 tumor model treated with antithrombin III inhibitor. In all cases, comparisons of the enzyme responsive and enzyme unresponsive CEST signals were critical for the detection of enzyme activity. CONCLUSIONS This study has established that catalyCEST MRI with an exogenous diaCEST agent can evaluate enzyme activity and inhibition in solution, in vitro and in vivo.
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Affiliation(s)
- Sanhita Sinharay
- Department of Chemistry and Biochemistry, University of Arizona, Tucson, AZ, USA
| | - Edward A Randtke
- Department of Medical Imaging, University of Arizona, 1515 N. Campbell Avenue, Tucson, AZ, 84724-5024, USA
| | - Christine M Howison
- Department of Medical Imaging, University of Arizona, 1515 N. Campbell Avenue, Tucson, AZ, 84724-5024, USA
| | - Natalia A Ignatenko
- Department of Cellular and Molecular Medicine, University of Arizona, Tucson, AZ, USA.,University of Arizona Cancer Center, University of Arizona, Tucson, AZ, USA
| | - Mark D Pagel
- Department of Chemistry and Biochemistry, University of Arizona, Tucson, AZ, USA. .,Department of Medical Imaging, University of Arizona, 1515 N. Campbell Avenue, Tucson, AZ, 84724-5024, USA. .,University of Arizona Cancer Center, University of Arizona, Tucson, AZ, USA. .,Department of Cancer Systems Imaging, MD Anderson Cancer Center, 1881 East Road, Houston, TX, 77054, USA.
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Shah S, Sinharay S, Matsuda K, Schreiber-Stainthorp W, Muthusamy S, Lee D, Wakim P, Hirsch V, Nath A, Di Mascio M, Hammoud DA. Potential Mechanism for HIV-Associated Depression: Upregulation of Serotonin Transporters in SIV-Infected Macaques Detected by 11C-DASB PET. Front Psychiatry 2019; 10:362. [PMID: 31178771 PMCID: PMC6543249 DOI: 10.3389/fpsyt.2019.00362] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/27/2018] [Accepted: 05/08/2019] [Indexed: 12/25/2022] Open
Abstract
Purpose: Increased incidence of depression in HIV+ patients is associated with lower adherence to treatment and increased morbidity/mortality. One possible underlying pathophysiology is serotonergic dysfunction. In this study, we used an animal model of HIV, the SIV-infected macaque, to longitudinally image serotonin transporter (SERT) expression before and after inoculation, using 11C-DASB (SERT ligand) PET imaging. Methods: We infected seven rhesus macaques with a neurovirulent SIV strain and imaged them at baseline and multiple time points after inoculation (group A). Pyrosequencing methylation analysis of the SERT promoter region was performed. We also measured SERT mRNA/protein in brain single-cell suspensions from another group (group B) of SIV-infected animals (n = 13). Results: Despite some animals showing early fluctuations, 86% of our group A animals eventually showed a net increase in midbrain/thalamus binding potential (BPND) over the course of their disease (mean increased binding between last time point and baseline = 30.2% and 32.2%, respectively). Repeated-measures mixed-model analysis showed infection duration to be predictive of midbrain BPND (p = 0.039). Thalamic BPND was statistically significantly associated with multiple CSF cytokines (P < 0.05). There was higher SERT protein levels in the second group (group B) of SIV-infected animals with SIV encephalitis (SIVE) compared to those without SIVE (p = 0.014). There were no longitudinal changes in SERT gene promoter region percentage methylation between baselines and last time points in group A animals. Conclusion: Upregulated SERT leading to lower synaptic levels of serotonin is a possible mechanism of depression in HIV+ patients, and extrapolating our conclusions from SIV to HIV should be sought using translational human studies.
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Affiliation(s)
- Swati Shah
- Center for Infectious Disease Imaging (CIDI), Radiology and Imaging Sciences,Clinical Center, National Institutes of Health (NIH), Bethesda, MD, United States
| | - Sanhita Sinharay
- Center for Infectious Disease Imaging (CIDI), Radiology and Imaging Sciences,Clinical Center, National Institutes of Health (NIH), Bethesda, MD, United States
| | - Kenta Matsuda
- Laboratory of Molecular Microbiology, National Institute of Allergy and Infectious Diseases (NIAID), NIH, Bethesda, MD, United States
| | - William Schreiber-Stainthorp
- Center for Infectious Disease Imaging (CIDI), Radiology and Imaging Sciences,Clinical Center, National Institutes of Health (NIH), Bethesda, MD, United States
| | - Siva Muthusamy
- Center for Infectious Disease Imaging (CIDI), Radiology and Imaging Sciences,Clinical Center, National Institutes of Health (NIH), Bethesda, MD, United States
| | - Dianne Lee
- Center for Infectious Disease Imaging (CIDI), Radiology and Imaging Sciences,Clinical Center, National Institutes of Health (NIH), Bethesda, MD, United States
| | - Paul Wakim
- Biostatistics and Clinical Epidemiology Service, Clinical Center, NIH, Bethesda, MD, United States
| | - Vanessa Hirsch
- Laboratory of Molecular Microbiology, National Institute of Allergy and Infectious Diseases (NIAID), NIH, Bethesda, MD, United States
| | - Avindra Nath
- National Institute of Neurological Disorder and Stroke (NINDS), NIH, Bethesda, MD, United States
| | - Michele Di Mascio
- AIDS Imaging Research Section, Division of Clinical Research, NIAID, NIH, Rockville, MD, United States
| | - Dima A Hammoud
- Center for Infectious Disease Imaging (CIDI), Radiology and Imaging Sciences,Clinical Center, National Institutes of Health (NIH), Bethesda, MD, United States
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Hammoud DA, Sinharay S, Steinbach S, Wakim PG, Geannopoulos K, Traino K, Dey AK, Tramont E, Rapoport SI, Snow J, Mehta NN, Smith BR, Nath A. Global and regional brain hypometabolism on FDG-PET in treated HIV-infected individuals. Neurology 2018; 91:e1591-e1601. [PMID: 30258017 DOI: 10.1212/wnl.0000000000006398] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/10/2018] [Accepted: 07/16/2018] [Indexed: 02/07/2023] Open
Abstract
OBJECTIVE To quantitatively measure brain glucose metabolism in treated HIV-positive individuals with [18F]-labeled fluorodeoxyglucose (FDG) PET/CT. METHODS We performed a cross-sectional comparison of FDG uptake in 47 treated HIV+ individuals, 10 age-matched controls (HIV-) sharing many of the comorbid conditions seen in the HIV+ group, and 19 age-matched healthy controls (HCs). We compared whole-brain (WB) and regional FDG standardized uptake values (SUVs) of select subcortical/central structures among the groups and correlated the values to clinical and neuropsychological assessments. A variable selection model was used to predict SUVs in HIV+ (n = 47) and in combined HIV+ and HIV- participants (n = 57). RESULTS We found lower WB SUVmax in HIV+ participants compared to HCs but not to HIV- participants. Among the relative SUVmean measurements (regional SUVmean/WB SUVmean), only relative thalamic uptake values were lower in HIV+ compared to HIV- participants. When HIV+ and HIV- participants were grouped, cardiovascular disease risk scores best predicted WB SUVmean and SUVmax, while HIV status best predicted thalamic relative SUVmean. CONCLUSIONS We identified an important role for cardiovascular disease in neuronal loss/dysfunction, as measured by FDG-PET, in treated HIV+ patients. This underscores the need for shifting the focus of clinical intervention in this vulnerable population from HIV effects alone to a wider set of comorbid conditions, mainly cardiovascular disease. Only the thalamus showed significantly lower relative uptake in the HIV+ compared to the HC and HIV- groups. This needs to be further evaluated for underlying pathophysiology and potential association with memory, executive functioning, and attention deficits seen in the HIV+ population.
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Affiliation(s)
- Dima A Hammoud
- From the Center for Infectious Disease Imaging, Radiology and Imaging Sciences (D.A.H., S. Sinharay), Clinical Center, National Institute of Neurological Diseases and Stroke (S. Steinbach, K.G., B.R.S., A.N.), Biostatistics and Clinical Epidemiology Service (P.G.W.), Clinical Center, National Institute of Mental Health (K.T., J.S.), National Heart, Lung, and Blood Institute (A.K.D., N.N.M.), National Institute for Allergy and Infectious Diseases (E.T.), and National Institute on Alcohol Abuse and Alcoholism (S.I.R.), NIH, Bethesda, MD.
| | - Sanhita Sinharay
- From the Center for Infectious Disease Imaging, Radiology and Imaging Sciences (D.A.H., S. Sinharay), Clinical Center, National Institute of Neurological Diseases and Stroke (S. Steinbach, K.G., B.R.S., A.N.), Biostatistics and Clinical Epidemiology Service (P.G.W.), Clinical Center, National Institute of Mental Health (K.T., J.S.), National Heart, Lung, and Blood Institute (A.K.D., N.N.M.), National Institute for Allergy and Infectious Diseases (E.T.), and National Institute on Alcohol Abuse and Alcoholism (S.I.R.), NIH, Bethesda, MD
| | - Sally Steinbach
- From the Center for Infectious Disease Imaging, Radiology and Imaging Sciences (D.A.H., S. Sinharay), Clinical Center, National Institute of Neurological Diseases and Stroke (S. Steinbach, K.G., B.R.S., A.N.), Biostatistics and Clinical Epidemiology Service (P.G.W.), Clinical Center, National Institute of Mental Health (K.T., J.S.), National Heart, Lung, and Blood Institute (A.K.D., N.N.M.), National Institute for Allergy and Infectious Diseases (E.T.), and National Institute on Alcohol Abuse and Alcoholism (S.I.R.), NIH, Bethesda, MD
| | - Paul G Wakim
- From the Center for Infectious Disease Imaging, Radiology and Imaging Sciences (D.A.H., S. Sinharay), Clinical Center, National Institute of Neurological Diseases and Stroke (S. Steinbach, K.G., B.R.S., A.N.), Biostatistics and Clinical Epidemiology Service (P.G.W.), Clinical Center, National Institute of Mental Health (K.T., J.S.), National Heart, Lung, and Blood Institute (A.K.D., N.N.M.), National Institute for Allergy and Infectious Diseases (E.T.), and National Institute on Alcohol Abuse and Alcoholism (S.I.R.), NIH, Bethesda, MD
| | - Katrina Geannopoulos
- From the Center for Infectious Disease Imaging, Radiology and Imaging Sciences (D.A.H., S. Sinharay), Clinical Center, National Institute of Neurological Diseases and Stroke (S. Steinbach, K.G., B.R.S., A.N.), Biostatistics and Clinical Epidemiology Service (P.G.W.), Clinical Center, National Institute of Mental Health (K.T., J.S.), National Heart, Lung, and Blood Institute (A.K.D., N.N.M.), National Institute for Allergy and Infectious Diseases (E.T.), and National Institute on Alcohol Abuse and Alcoholism (S.I.R.), NIH, Bethesda, MD
| | - Katherine Traino
- From the Center for Infectious Disease Imaging, Radiology and Imaging Sciences (D.A.H., S. Sinharay), Clinical Center, National Institute of Neurological Diseases and Stroke (S. Steinbach, K.G., B.R.S., A.N.), Biostatistics and Clinical Epidemiology Service (P.G.W.), Clinical Center, National Institute of Mental Health (K.T., J.S.), National Heart, Lung, and Blood Institute (A.K.D., N.N.M.), National Institute for Allergy and Infectious Diseases (E.T.), and National Institute on Alcohol Abuse and Alcoholism (S.I.R.), NIH, Bethesda, MD
| | - Amit K Dey
- From the Center for Infectious Disease Imaging, Radiology and Imaging Sciences (D.A.H., S. Sinharay), Clinical Center, National Institute of Neurological Diseases and Stroke (S. Steinbach, K.G., B.R.S., A.N.), Biostatistics and Clinical Epidemiology Service (P.G.W.), Clinical Center, National Institute of Mental Health (K.T., J.S.), National Heart, Lung, and Blood Institute (A.K.D., N.N.M.), National Institute for Allergy and Infectious Diseases (E.T.), and National Institute on Alcohol Abuse and Alcoholism (S.I.R.), NIH, Bethesda, MD
| | - Edmund Tramont
- From the Center for Infectious Disease Imaging, Radiology and Imaging Sciences (D.A.H., S. Sinharay), Clinical Center, National Institute of Neurological Diseases and Stroke (S. Steinbach, K.G., B.R.S., A.N.), Biostatistics and Clinical Epidemiology Service (P.G.W.), Clinical Center, National Institute of Mental Health (K.T., J.S.), National Heart, Lung, and Blood Institute (A.K.D., N.N.M.), National Institute for Allergy and Infectious Diseases (E.T.), and National Institute on Alcohol Abuse and Alcoholism (S.I.R.), NIH, Bethesda, MD
| | - Stanley I Rapoport
- From the Center for Infectious Disease Imaging, Radiology and Imaging Sciences (D.A.H., S. Sinharay), Clinical Center, National Institute of Neurological Diseases and Stroke (S. Steinbach, K.G., B.R.S., A.N.), Biostatistics and Clinical Epidemiology Service (P.G.W.), Clinical Center, National Institute of Mental Health (K.T., J.S.), National Heart, Lung, and Blood Institute (A.K.D., N.N.M.), National Institute for Allergy and Infectious Diseases (E.T.), and National Institute on Alcohol Abuse and Alcoholism (S.I.R.), NIH, Bethesda, MD
| | - Joseph Snow
- From the Center for Infectious Disease Imaging, Radiology and Imaging Sciences (D.A.H., S. Sinharay), Clinical Center, National Institute of Neurological Diseases and Stroke (S. Steinbach, K.G., B.R.S., A.N.), Biostatistics and Clinical Epidemiology Service (P.G.W.), Clinical Center, National Institute of Mental Health (K.T., J.S.), National Heart, Lung, and Blood Institute (A.K.D., N.N.M.), National Institute for Allergy and Infectious Diseases (E.T.), and National Institute on Alcohol Abuse and Alcoholism (S.I.R.), NIH, Bethesda, MD
| | - Nehal N Mehta
- From the Center for Infectious Disease Imaging, Radiology and Imaging Sciences (D.A.H., S. Sinharay), Clinical Center, National Institute of Neurological Diseases and Stroke (S. Steinbach, K.G., B.R.S., A.N.), Biostatistics and Clinical Epidemiology Service (P.G.W.), Clinical Center, National Institute of Mental Health (K.T., J.S.), National Heart, Lung, and Blood Institute (A.K.D., N.N.M.), National Institute for Allergy and Infectious Diseases (E.T.), and National Institute on Alcohol Abuse and Alcoholism (S.I.R.), NIH, Bethesda, MD
| | - Bryan R Smith
- From the Center for Infectious Disease Imaging, Radiology and Imaging Sciences (D.A.H., S. Sinharay), Clinical Center, National Institute of Neurological Diseases and Stroke (S. Steinbach, K.G., B.R.S., A.N.), Biostatistics and Clinical Epidemiology Service (P.G.W.), Clinical Center, National Institute of Mental Health (K.T., J.S.), National Heart, Lung, and Blood Institute (A.K.D., N.N.M.), National Institute for Allergy and Infectious Diseases (E.T.), and National Institute on Alcohol Abuse and Alcoholism (S.I.R.), NIH, Bethesda, MD.
| | - Avindra Nath
- From the Center for Infectious Disease Imaging, Radiology and Imaging Sciences (D.A.H., S. Sinharay), Clinical Center, National Institute of Neurological Diseases and Stroke (S. Steinbach, K.G., B.R.S., A.N.), Biostatistics and Clinical Epidemiology Service (P.G.W.), Clinical Center, National Institute of Mental Health (K.T., J.S.), National Heart, Lung, and Blood Institute (A.K.D., N.N.M.), National Institute for Allergy and Infectious Diseases (E.T.), and National Institute on Alcohol Abuse and Alcoholism (S.I.R.), NIH, Bethesda, MD
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Schreiber-Stainthorp W, Sinharay S, Srinivasula S, Shah S, Wang J, Dodd L, Lane HC, Di Mascio M, Hammoud DA. Brain 18F-FDG PET of SIV-infected macaques after treatment interruption or initiation. J Neuroinflammation 2018; 15:207. [PMID: 30007411 PMCID: PMC6046092 DOI: 10.1186/s12974-018-1244-z] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/23/2018] [Accepted: 06/29/2018] [Indexed: 01/13/2023] Open
Abstract
Background Although rates of severe HIV-associated neurocognitive disorders have declined in the post-antiretroviral treatment (ART) era, subtle deficits persist, possibly exacerbated by treatment non-adherence. The actual effects of ART interruption/initiation on brain glucose metabolism as a reflection of viral replication and neuroinflammation remain unclear. Our study investigates how treatment initiation and interruption alter brain glucose metabolism in SIV-infected macaques, using 18F-FDG PET in correlation with plasma and CSF viral loads (VL) and cytokine levels. Methods SIV-infected macaques (n = 7) underwent ART initiation only, ART interruption only, or both. Five uninfected animals served as controls. 18F-FDG PET imaging was performed at baseline and 1, 3, and 6 months after treatment modification. Mean and maximum standardized uptake values (SUV) for the whole-brain and subregions were calculated. Plasma and CSF VL and cytokine levels were measured. Paired t tests evaluated acute changes in whole-brain SUV from baseline to 1 month, while mixed-effect linear regression models evaluated changes over multiple timepoints and correlated SUV values with disease markers. Results ART interruption was associated with increased SUVmean and SUVmax acutely, after 1 month (SUVmean 95% CI [0.044–0.786 g/ml], p = 0.037; SUVmax 95% CI [0.122–3.167 g/ml], p = 0.041). The correlation between SUV and time, however, was not significant when evaluated across all timepoints. Increased SUVmean and SUVmax correlated with decreased CD4+ and CD8+ T-cell counts and increased plasma VL. SUVmax was positively associated with increases in CSF VL, and there were borderline positive associations between SUVmax and IL-2, and between SUVmean and IL-15. The treatment initiation group showed no associations between imaging and disease biomarkers despite viral suppression, reduced cytokine levels, and increased CD4+ and CD8+ T-cell counts. Conclusions ART interruption is associated with increased brain glucose metabolism within 1 month of treatment cessation, which, in concert with increased levels of pro-inflammatory cytokines in the CSF, may reflect neuroinflammation in the setting of viral rebound. Although we cannot assert neurologic damage in association with cerebral hypermetabolism, it is a concerning outcome of ART non-adherence. Treatment initiation, meanwhile, did not result in significant changes in brain metabolism. HIV-induced neuroinflammation may require a longer period to abate than our follow-up period allowed. Electronic supplementary material The online version of this article (10.1186/s12974-018-1244-z) contains supplementary material, which is available to authorized users.
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Affiliation(s)
| | - Sanhita Sinharay
- Center for Infectious Disease Imaging, Clinical Center, National Institutes of Health, Bethesda, MD, USA
| | - Sharat Srinivasula
- Clinical Research Directorate/Clinical Monitoring Research Program, Leidos Biomedical Research, Inc., National Cancer Institute Campus at Frederick, Frederick, MD, USA
| | - Swati Shah
- Center for Infectious Disease Imaging, Clinical Center, National Institutes of Health, Bethesda, MD, USA
| | - Jing Wang
- Clinical Research Directorate/Clinical Monitoring Research Program, Leidos Biomedical Research, Inc., National Cancer Institute Campus at Frederick, Frederick, MD, USA
| | - Lori Dodd
- Biostatistics Research Branch, Division of Clinical Research, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Rockville, MD, USA
| | - H Clifford Lane
- Clinical and Molecular Retrovirology Section, Laboratory of Immunoregulation, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Bethesda, MD, USA
| | - Michele Di Mascio
- Biostatistics Research Branch, Division of Clinical Research, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Rockville, MD, USA
| | - Dima A Hammoud
- Center for Infectious Diseases Imaging (CIDI), Clinical Center, National Institutes of Health (NIH), 10 Center Drive, Building 10, Room 1C-368, Bethesda, MD, 20892, USA.
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Casas R, Muthusamy S, Wakim PG, Sinharay S, Lentz MR, Reid WC, Hammoud DA. MR brain volumetric measurements are predictive of neurobehavioral impairment in the HIV-1 transgenic rat. Neuroimage Clin 2017; 17:659-666. [PMID: 29204344 PMCID: PMC5705794 DOI: 10.1016/j.nicl.2017.11.018] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 04/18/2017] [Revised: 09/11/2017] [Accepted: 11/18/2017] [Indexed: 01/18/2023]
Abstract
Introduction HIV infection is known to be associated with brain volume loss, even in optimally treated patients. In this study, we assessed whether dynamic brain volume changes over time are predictive of neurobehavorial performance in the HIV-1 transgenic (Tg) rat, a model of treated HIV-positive patients. Materials and methods Cross-sectional brain MRI imaging was first performed comparing Tg and wild type (WT) rats at 3 and 19 months of age. Longitudinal MRI and neurobehavioral testing of another group of Tg and WT rats was then performed from 5 to 23 weeks of age. Whole brain and subregional image segmentation was used to assess the rate of brain growth over time. We used repeated-measures mixed models to assess differences in brain volumes and to establish how predictive the volume differences are of specific neurobehavioral deficits. Results Cross-sectional imaging showed smaller whole brain volumes in Tg compared to WT rats at 3 and at 19 months of age. Longitudinally, Tg brain volumes were smaller than age-matched WT rats at all time points, starting as early as 5 weeks of age. The Tg striatal growth rate delay between 5 and 9 weeks of age was greater than that of the whole brain. Striatal volume in combination with genotype was the most predictive of rota-rod scores and in combination with genotype and age was the most predictive of total exploratory activity scores in the Tg rats. Conclusion The disproportionately delayed striatal growth compared to whole brain between 5 and 9 weeks of age and the role of striatal volume in predicting neurobehavioral deficits suggest an important role of the dopaminergic system in HIV associated neuropathology. This might explain problems with motor coordination and executive decisions in this animal model. Smaller brain and subregional volumes and neurobehavioral deficits were seen as early as 5 weeks of age, suggesting an early brain insult in the Tg rat. Neuroprotective therapy testing in this model should thus target this early stage of development, before brain damage becomes irreversible. HIV infection is known to be associated with brain volume loss. HIV transgenic rats showed smaller brain volumes than wild type rats. Tg rats showed disproportionate loss of volume in the striatum compared to brain. Tg striatal volume loss along with genotype/age predict neurobehavioral deficits.
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Affiliation(s)
- Rafael Casas
- Center for Infectious Disease Imaging (CIDI), Radiology and Imaging Sciences, Clinical Center, National Institutes of Health (NIH), Bethesda, MD, United States
| | - Siva Muthusamy
- Center for Infectious Disease Imaging (CIDI), Radiology and Imaging Sciences, Clinical Center, National Institutes of Health (NIH), Bethesda, MD, United States
| | - Paul G Wakim
- Biostatistics and Clinical Epidemiology Service, Clinical Center, National Institutes of Health (NIH), Bethesda, MD, United States
| | - Sanhita Sinharay
- Center for Infectious Disease Imaging (CIDI), Radiology and Imaging Sciences, Clinical Center, National Institutes of Health (NIH), Bethesda, MD, United States
| | - Margaret R Lentz
- Center for Infectious Disease Imaging (CIDI), Radiology and Imaging Sciences, Clinical Center, National Institutes of Health (NIH), Bethesda, MD, United States
| | - William C Reid
- Center for Infectious Disease Imaging (CIDI), Radiology and Imaging Sciences, Clinical Center, National Institutes of Health (NIH), Bethesda, MD, United States
| | - Dima A Hammoud
- Center for Infectious Disease Imaging (CIDI), Radiology and Imaging Sciences, Clinical Center, National Institutes of Health (NIH), Bethesda, MD, United States.
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Sinharay S, Howison CM, Baker AF, Pagel MD. Detecting in vivo urokinase plasminogen activator activity with a catalyCEST MRI contrast agent. NMR Biomed 2017; 30:10.1002/nbm.3721. [PMID: 28370884 PMCID: PMC5704996 DOI: 10.1002/nbm.3721] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/12/2016] [Revised: 02/04/2017] [Accepted: 02/06/2017] [Indexed: 05/22/2023]
Abstract
Urokinase plasminogen activator (uPA) promotes tumor invasion and metastasis. The monitoring of uPA activity using molecular imaging may have prognostic value and be predictive for response to anti-cancer therapies. However, the detection of in vivo enzyme activity with molecular imaging remains a challenge. To address this problem, we designed a nonmetallic contrast agent, GR-4Am-SA, that can be detected with chemical exchange saturation transfer (CEST) MRI. This agent has a peptide that is cleaved by uPA, which causes a CEST signal at 5.0 ppm to decrease, and also has a salicylic acid moiety that can produce a CEST signal at 9.5 ppm, which is largely unresponsive to enzyme activity. The two CEST signals were used to determine a reaction coordinate, representing the extent of enzyme-catalyzed cleavage of the GR-4Am-SA agent during an experimental study. Initial biochemical studies showed that GR-4Am-SA could detect uPA activity in reducing conditions. Subsequently, we used our catalyCEST MRI protocol with the agent to detect the uPA catalysis of GR-4Am-SA in a flank xenograft model of Capan-2 pancreatic cancer. The results showed an average reaction coordinate of 80% ± 8%, which was strongly dependent on the CEST signal at 5.0 ppm. The relative independence of the reaction coordinate on the CEST signal at 9.5 ppm showed that the detection of enzyme activity was largely independent of the concentration of GR-4Am-SA within the tumor tissue. These results demonstrated the advantages of a single CEST agent with biomarker-responsive and unresponsive signals for reliably assessing enzyme activity during in vivo cancer studies.
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Affiliation(s)
- Sanhita Sinharay
- Department of Chemistry and Biochemistry, University of Arizona, Tucson, AZ
| | | | - Amanda F. Baker
- University of Arizona Cancer Center, University of Arizona, Tucson, AZ
| | - Mark D. Pagel
- Department of Chemistry and Biochemistry, University of Arizona, Tucson, AZ
- University of Arizona Cancer Center, University of Arizona, Tucson, AZ
- Department of Medical Imaging, University of Arizona, Tucson, AZ
- Corresponding Author: Mark D. Pagel, University of Arizona Cancer Center, 1515 N. Campbell Avenue, Tucson, AZ 85724-5024, Tel: (520)-404-7049, Fax: (520)-626-0395,
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Riggle BA, Sinharay S, Hammoud D, Munasinghe J, Slusher B, Powell JD, Seydel K, Taylor T, Miller LH, Pierce SK. Using magnetic resonance imaging to elucidate the mechanism of experimental cerebral malaria rescue by 6-diazo-5-oxo-norleucine. The Journal of Immunology 2017. [DOI: 10.4049/jimmunol.198.supp.123.19] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/03/2023]
Abstract
Abstract
We have previously demonstrated the efficacy of 6-diazo-5-oxo-L-norleucine (DON), a glutamine analog, as a possible adjunctive therapy to mitigate the clinical severity of human cerebral malaria (HCM) (Gordon et al. PNAS 2016). The pathology of HCM is heterogeneous, but generally includes the accumulation of infected red blood cells in the brain vascular endothelium, cerebral microhemorrhages, compromised blood-brain barrier and brain swelling. These changes manifest in severe neurologic symptoms including headache, fever, ataxia, seizures, retinopathy, and coma. The mouse model of CM, experimental cerebral malaria (ECM), approximates the main characteristics of HCM when susceptible C57BL/6 mice are infected with Plasmodium berghei ANKA (PbA) parasites. Studies in these mice found that treatment with DON, even in late stage ECM, rescued animals and increased survival while mitigating and reversing blood-brain barrier dysfunction and brain swelling. Recently, Seydel et al. (NEJM 2015) used magnetic resonance imaging (MRI) to characterize HCM pathology and correlate it to disease severity in children in Malawi. They observed increased brain volume in children that died from HCM that was uncommon in children that survived HCM. Herein, we perform MRI studies in the mouse model to determine if the disease course effectively recapitulates that of HCM, based on morphological changes in MRI. These studies may help elucidate the mechanisms underlying CM pathology, aiding the development of effective treatments. Furthermore, we utilize MRI to probe the mechanisms of action of recovery with DON treatment in order to evaluate the drug for possible clinical trials in HCM.
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Abstract
Recent advances in magnetic resonance imaging (MRI) contrast agents have provided new capabilities for biomarker detection through molecular imaging. MRI contrast agents based on the T2 exchange mechanism have more recently expanded the armamentarium of agents for molecular imaging. Compared with T1 and T2* agents, T2 exchange agents have a slower chemical exchange rate, which improves the ability to design these MRI contrast agents with greater specificity for detecting the intended biomarker. MRI contrast agents that are detected through chemical exchange saturation transfer (CEST) have even slower chemical exchange rates. Another emerging class of MRI contrast agents uses hyperpolarized (13)C to detect the agent with outstanding sensitivity. These hyperpolarized (13)C agents can be used to track metabolism and monitor characteristics of the tissue microenvironment. Together, these various MRI contrast agents provide excellent opportunities to develop molecular imaging for biomarker detection.
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Affiliation(s)
- Sanhita Sinharay
- Department of Chemistry and Biochemistry, University of Arizona, Tucson, Arizona 85724;
| | - Mark D Pagel
- Department of Chemistry and Biochemistry, University of Arizona, Tucson, Arizona 85724;
- Department of Medical Imaging, University of Arizona, Tucson, Arizona 85724;
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17
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Sinharay S, Randtke EA, Jones KM, Howison CM, Chambers SK, Kobayashi H, Pagel MD. Noninvasive detection of enzyme activity in tumor models of human ovarian cancer using catalyCEST MRI. Magn Reson Med 2016; 77:2005-2014. [PMID: 27221386 DOI: 10.1002/mrm.26278] [Citation(s) in RCA: 31] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/10/2016] [Revised: 04/25/2016] [Accepted: 04/25/2016] [Indexed: 12/17/2022]
Abstract
PURPOSE We proposed to detect the in vivo enzyme activity of γ-glutamyl transferase (GGT) within mouse models of human ovarian cancers using catalyCEST MRI with a diamagnetic CEST agent. METHODS A CEST-FISP MRI protocol and a diamagnetic CEST agent were developed to detect GGT enzyme activity in biochemical solution. A quantitative Michaelis-Menten enzyme kinetics study was performed to confirm that catalyCEST MRI can measure enzyme activity. In vivo catalyCEST MRI studies generated pixel-wise activity maps of GGT activities. Ex vivo fluorescence imaging was performed for validation. RESULTS CatalyCEST MRI selectively detected two CEST signals from a single CEST agent, whereby one CEST signal was responsive to GGT enzyme activity and the other CEST signal was an unresponsive control signal. The comparison of these CEST signals facilitated in vivo catalyCEST MRI studies that detected high GGT activity in OVCAR-8 tumors, low GGT activity in OVCAR-3 tumors, and low or no GGT activity in muscle tissues. CONCLUSION CatalyCEST MRI with a diamagnetic CEST agent can detect the level of GGT enzyme activity within in vivo tumor models of human ovarian cancers. Magn Reson Med 77:2005-2014, 2017. © 2016 International Society for Magnetic Resonance in Medicine.
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Affiliation(s)
- Sanhita Sinharay
- Department of Chemistry and Biochemistry, University of Arizona, Tucson, Arizona, USA
| | - Edward A Randtke
- Department of Medical Imaging, University of Arizona, Tucson, Arizona, USA
| | - Kyle M Jones
- Biomedical Engineering Graduate Interdisciplinary Program, University of Arizona, Tucson, Arizona, USA
| | | | - Setsuko K Chambers
- Department of Obstetrics and Gynecology, University of Arizona, Tucson, Arizona, USA.,University of Arizona Cancer Center, University of Arizona, Tucson, Arizona, USA
| | - Hisataka Kobayashi
- Laboratory of Molecular Theranostics, National Cancer Institute, NIH, Bethesda, Maryland, USA
| | - Mark D Pagel
- Department of Chemistry and Biochemistry, University of Arizona, Tucson, Arizona, USA.,Department of Medical Imaging, University of Arizona, Tucson, Arizona, USA.,University of Arizona Cancer Center, University of Arizona, Tucson, Arizona, USA
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18
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Abstract
A chemical exchange saturation transfer (CEST) MRI contrast agent has been developed that detects sulfatase enzyme activity. The agent produces a CEST signal at δ=5.0 ppm before enzyme activity, and a second CEST signal appears at δ=9.0 ppm after the enzyme cleaves a sulfate group from the agent. The comparison of the two signals improved detection of sulfatase activity.
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Affiliation(s)
- Sanhita Sinharay
- Department of Chemistry and Biochemistry, University of Arizona, Tucson, AZ, USA
| | | | - Jasmine P Acfalle
- Department of Chemistry and Biochemistry, University of Arizona, Tucson, AZ, USA
| | - Mark D Pagel
- Department of Medical Imaging, University of Arizona, 1515 N. Campbell Ave., Tucson, AZ, USA.
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Fernández-Cuervo G, Sinharay S, Pagel MD. Inside Cover: A CatalyCEST MRI Contrast Agent that Can Simultaneously Detect Two Enzyme Activities (ChemBioChem 5/2016). Chembiochem 2016. [DOI: 10.1002/cbic.201600080] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Affiliation(s)
- Gabriela Fernández-Cuervo
- Department of Pharmaceutical Sciences; University of Arizona; 1515 N. Campbell Ave. Tucson AZ 85724 USA
| | - Sanhita Sinharay
- Department of Chemistry and Biochemistry; University of Arizona; 1515 N. Campbell Ave. Tucson AZ 85724 USA
| | - Mark D. Pagel
- Department of Medical Imaging; University of Arizona; 1515 N. Campbell Ave. Tucson AZ 85724 USA
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20
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Abstract
The simultaneous detection of multiple enzyme activities can improve the specificity of disease diagnoses. We therefore synthesized and characterized a diamagnetic chemical exchange saturation transfer (CEST) MRI contrast agent that can simultaneously detect two enzyme activities. Sulfatase and esterase enzymes cleave the ligands of the CEST agent, releasing salicylic acid that can be detected with CEST MRI. Importantly, both enzymes are required to activate the agent to produce a CEST MRI contrast, and the CEST agent was stable without enzyme treatment. These results established that this diamagnetic CEST MRI contrast agent is a platform technology with a modular design that can be potentially exploited to detect other combinations of enzyme activities, which can expand the armamentarium of contrast agents for molecular imaging.
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Affiliation(s)
- Gabriela Fernández-Cuervo
- Department of Pharmaceutical Sciences, University of Arizona, 1515 N. Campbell Ave., Tucson, AZ, 85724, USA
| | - Sanhita Sinharay
- Department of Chemistry and Biochemistry, University of Arizona, 1515 N. Campbell Ave., Tucson, AZ, 85724, USA
| | - Mark D Pagel
- Department of Medical Imaging, University of Arizona, 1515 N. Campbell Ave., Tucson, AZ, 85724, USA.
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Abstract
The pyrrolyldipyrrin motif is found in several naturally occurring prodigiosin pigments. The potential roles of the interactions of prodigiosins with transition metals and the properties of metal-bound pyrrolyldipyrrins, however, have been difficult to assess because of the very limited number of well-characterized stable complexes. Here, we show that the introduction of a meso-aryl substituent and an ethyl ester group during the sequential assembly of the three heterocycles affords a pyrrolyldipyrrin of enhanced coordinating abilities when compared to that of natural prodigiosins. UV-visible absorption studies indicate that this ligand promptly binds Zn(II) ions with 2:1 ligand-to-metal stoichiometry and Cu(II) ions with 1:1 stoichiometry. Notably, no addition of base is required for the formation of the resulting stable complexes. The crystal structures reveal that whereas the tetrahedral zinc center engages two nitrogen donors on each ligand, the pseudosquare planar copper complex features coordination of all three pyrrolic nitrogen atoms and employs the ester group as a neutral ligand. This first example of coordination of a redox-active transition metal within a fully conjugated pyrrolyldipyrrin framework was investigated spectroscopically by electron paramagnetic resonance to show that the 1:1 metal-to-ligand ratio found in the crystal structure is also maintained in solution.
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Affiliation(s)
- Tsuhen M Chang
- Department of Chemistry and Biochemistry, University of Arizona , 1306 East University Boulevard, Tucson, Arizona 85721-0041, United States
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Sinharay S, Stern HS, Russell D. The use of multiple imputation for the analysis of missing data. Psychol Methods 2001; 6:317-29. [PMID: 11778675] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/23/2023]
Abstract
This article provides a comprehensive review of multiple imputation (MI), a technique for analyzing data sets with missing values. Formally, MI is the process of replacing each missing data point with a set of m > 1 plausible values to generate m complete data sets. These complete data sets are then analyzed by standard statistical software, and the results combined, to give parameter estimates and standard errors that take into account the uncertainty due to the missing data values. This article introduces the idea behind MI, discusses the advantages of MI over existing techniques for addressing missing data, describes how to do MI for real problems, reviews the software available to implement MI, and discusses the results of a simulation study aimed at finding out how assumptions regarding the imputation model affect the parameter estimates provided by MI.
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Affiliation(s)
- S Sinharay
- Department of Statistics, Iowa State University, Ames 50011-1210, USA
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Abstract
The binding of the nonintercalating dye berenil to the 70S ribosome of Escherichia coli has been demonstrated by spectrophotometric measurements and gel filtration through Biogel P100 column. The berenil spectrum is gradually shifted towards the red region with the increasing amount of ribosome added, the isosbestic point being at 375 nm. There is positive cooperativity in the binding of berenil to the ribosome as demonstrated by the equilibrium dialysis. On binding with berenil, the ribosome is degraded faster by RNase I especially at low Mg++ concentration and its capacity to inhibit RNase I catalysed hydrolysis of ribopolymers is decreased. These indicate the unfolding of the structure of the ribosome.
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