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Fang Y, Reinl EL, Liu A, Prochaska TD, Malik M, Frolova AI, England SK, Imoukhuede PI. Quantification of surface-localized and total oxytocin receptor in myometrial smooth muscle cells. Heliyon 2024; 10:e25761. [PMID: 38384573 PMCID: PMC10878913 DOI: 10.1016/j.heliyon.2024.e25761] [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] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/18/2023] [Revised: 01/31/2024] [Accepted: 02/01/2024] [Indexed: 02/23/2024] Open
Abstract
Oxytocin acts through the oxytocin receptor (OXTR) to modulate uterine contractility. We previously identified OXTR genetic variants and showed that, in HEK293T cells, two of the OXTR protein variants localized to the cell surface less than wild-type OXTR. Here, we sought to measure OXTR in the more native human myometrial smooth muscle cell (HMSMC) line on both the cell-surface and across the whole cell, and used CRISPR editing to add an HA tag to the endogenous OXTR gene for anti-HA measurement. Quantitative flow cytometry revealed that these cells possessed 55,000 ± 3200 total OXTRs and 4900 ± 390 cell-surface OXTRs per cell. To identify any differential wild-type versus variant localization, we transiently transfected HMSMCs to exogenously express wild-type or variant OXTR with HA and green fluorescent protein tags. Total protein expression of wild-type OXTR and all tested variants were similar. However, the two variants with lower surface localization in HEK293T cells also presented lower surface localization in HMSMCs. Overall, we confirm the differential surface localization of variant OXTR in a more native cell type, and further demonstrate that the quantitative flow cytometry technique is adaptable to whole-cell measurements.
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Affiliation(s)
- Yingye Fang
- Department of Bioengineering, University of Washington, Seattle, WA, 98109, USA
| | - Erin L. Reinl
- Department of Obstetrics and Gynecology, Center for Reproductive Health Sciences, Washington University School of Medicine in St. Louis, St. Louis, MO, 63110, USA
| | - Audrey Liu
- Department of Obstetrics and Gynecology, Center for Reproductive Health Sciences, Washington University School of Medicine in St. Louis, St. Louis, MO, 63110, USA
| | - Trinidi D. Prochaska
- Department of Obstetrics and Gynecology, Center for Reproductive Health Sciences, Washington University School of Medicine in St. Louis, St. Louis, MO, 63110, USA
| | - Manasi Malik
- Department of Obstetrics and Gynecology, Center for Reproductive Health Sciences, Washington University School of Medicine in St. Louis, St. Louis, MO, 63110, USA
| | - Antonina I. Frolova
- Department of Obstetrics and Gynecology, Center for Reproductive Health Sciences, Washington University School of Medicine in St. Louis, St. Louis, MO, 63110, USA
| | - Sarah K. England
- Department of Obstetrics and Gynecology, Center for Reproductive Health Sciences, Washington University School of Medicine in St. Louis, St. Louis, MO, 63110, USA
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Fang Y, Chen L, Imoukhuede PI. Toward Blood-Based Precision Medicine: Identifying Age-Sex-Specific Vascular Biomarker Quantities on Circulating Vascular Cells. Cell Mol Bioeng 2023; 16:189-204. [PMID: 37456786 PMCID: PMC10338416 DOI: 10.1007/s12195-023-00771-1] [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] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/28/2023] [Accepted: 06/20/2023] [Indexed: 07/18/2023] Open
Abstract
Introduction Abnormal angiogenesis is central to vascular disease and cancer, and noninvasive biomarkers of vascular origin are needed to evaluate patients and therapies. Vascular endothelial growth factor receptors (VEGFRs) are often dysregulated in these diseases, making them promising biomarkers, but the need for an invasive biopsy has limited biomarker research on VEGFRs. Here, we pioneer a blood biopsy approach to quantify VEGFR plasma membrane localization on two circulating vascular proxies: circulating endothelial cells (cECs) and circulating progenitor cells (cPCs). Methods Using quantitative flow cytometry, we examined VEGFR expression on cECs and cPCs in four age-sex groups: peri/premenopausal females (aged < 50 years), menopausal/postmenopausal females (≥ 50 years), and younger and older males with the same age cut-off (50 years). Results cECs in peri/premenopausal females consisted of two VEGFR populations: VEGFR-low (~ 55% of population: population medians ~ 3000 VEGFR1 and 3000 VEGFR2/cell) and VEGFR-high (~ 45%: 138,000 VEGFR1 and 39,000-236,000 VEGFR2/cell), while the menopausal/postmenopausal group only possessed the VEGFR-low cEC population; and 27% of cECs in males exhibited high plasma membrane VEGFR expression (206,000 VEGFR1 and 155,000 VEGFR2/cell). The absence of VEGFR-high cEC subpopulations in menopausal/postmenopausal females suggests that their high-VEGFR cECs are associated with menstruation and could be noninvasive proxies for studying the intersection of age-sex in angiogenesis. VEGFR1 plasma membrane localization in cPCs was detected only in menopausal/postmenopausal females, suggesting a menopause-specific regenerative mechanism. Conclusions Overall, our quantitative, noninvasive approach targeting cECs and cPCs has provided the first insights into how sex and age influence VEGFR plasma membrane localization in vascular cells. Supplementary Information The online version contains supplementary material available at 10.1007/s12195-023-00771-1.
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Affiliation(s)
- Yingye Fang
- Department of Bioengineering, University of Washington, Seattle, WA USA
| | - Ling Chen
- Division of Biostatistics, Washington University in St. Louis School of Medicine, St. Louis, MO USA
| | - P. I. Imoukhuede
- Department of Bioengineering, University of Washington, Seattle, WA USA
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Fang Y, Malik M, England SK, Imoukhuede PI. Absolute Quantification of Plasma Membrane Receptors Via Quantitative Flow Cytometry. Methods Mol Biol 2022; 2475:61-77. [PMID: 35451749 PMCID: PMC9261967 DOI: 10.1007/978-1-0716-2217-9_4] [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] [Indexed: 01/03/2023]
Abstract
Plasma membrane receptors are transmembrane proteins that initiate cellular response following the binding of specific ligands (e.g., growth factors, hormones, and cytokines). The abundance of plasma membrane receptors can be a diagnostic or prognostic biomarker in many human diseases. One of the best techniques for measuring plasma membrane receptors is quantitative flow cytometry (qFlow). qFlow employs fluorophore-conjugated antibodies against the receptors of interest and corresponding fluorophore-loaded calibration beads offers standardized and reproducible measurements of plasma membrane receptors. More importantly, qFlow can achieve absolute quantification of plasma membrane receptors when phycoerythrin (PE) is the fluorophore of choice. Here we describe a detailed qFlow protocol to obtain absolute receptor quantities on the basis of PE calibration. This protocol is foundational for many previous and ongoing studies in quantifying tyrosine kinase receptors and G-protein-coupled receptors with in vitro cell models and ex vivo cell samples.
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Affiliation(s)
- Yingye Fang
- Department of Biomedical Engineering, Washington University in St. Louis, St. Louis, MO, USA
- University of Washington, Department of Bioengineering, Seattle, WA, USA
| | - Manasi Malik
- Center for Reproductive Health Sciences, Department of Obstetrics and Gynecology, Washington University School of Medicine, St. Louis, MO, USA
| | - Sarah K England
- Center for Reproductive Health Sciences, Department of Obstetrics and Gynecology, Washington University School of Medicine, St. Louis, MO, USA
| | - P I Imoukhuede
- Department of Biomedical Engineering, Washington University in St. Louis, St. Louis, MO, USA.
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Raghavan M, Yarzabek B, Zaitouna AJ, Krishnakumar S, Ramon DS. Strategies for the measurements of expression levels and half-lives of HLA class I allotypes. Hum Immunol 2019; 80:221-227. [PMID: 30735755 DOI: 10.1016/j.humimm.2019.02.001] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [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: 05/31/2018] [Revised: 12/05/2018] [Accepted: 02/01/2019] [Indexed: 12/12/2022]
Abstract
HLA class I molecules are highly polymorphic cell surface proteins that trigger immune responses by CD8+ T cells and natural killer (NK) cells. Most humans express six different HLA class I proteins encoded by the HLA-A, HLA-B and HLA-C genes. HLA class I molecules bind to peptide antigens and present these antigens to T cell receptors (TCR) of CD8+ T cells. HLA class I expression levels also regulate NK cell activation. The presence of individual HLA class I genes is linked to many different disease, transplantation and therapy outcomes. An understanding of HLA class I expression and stability patterns is fundamentally important towards a better understanding of the associations of HLA class I genes with disease and treatment outcomes, and towards HLA class I targeting for vaccine development. Quantitative flow cytometry allows for assessments of variations in expression levels of HLA class I molecules in cells from a single blood donor over time, as well as averaged measurements across donors for the same allotype. Since all HLA class I molecules are structurally-related, cellular measurements of the HLA class I expression levels and stabilities of individual variants in human cells require careful choices of donors and antibodies, which are discussed here.
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Affiliation(s)
- Malini Raghavan
- Department of Microbiology and Immunology, Michigan Medicine, 1150 W. Medical Center Drive, University of Michigan, Ann Arbor, MI 48109, USA.
| | - Brogan Yarzabek
- Department of Microbiology and Immunology, Michigan Medicine, 1150 W. Medical Center Drive, University of Michigan, Ann Arbor, MI 48109, USA
| | - Anita J Zaitouna
- Department of Microbiology and Immunology, Michigan Medicine, 1150 W. Medical Center Drive, University of Michigan, Ann Arbor, MI 48109, USA
| | - Sujatha Krishnakumar
- Sirona Genomics, Immucor Inc, Suite A, 1916 Old Middlefield Way Mountain View, CA 94043, USA
| | - Daniel S Ramon
- Department of Laboratory Medicine and Pathology, Mayo Clinic, 5777 E. Mayo Blvd, Phoenix, AZ 85054, USA
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Abstract
Accurately determining the number of peptide-MHC class I complexes on the cell surface is necessary when evaluating cellular processes or pharmaceuticals that alter the antigen presentation machinery. Here I describe a quantitative flow cytometry application for determining the number of peptide-MHC complexes on the surface of cells grown in tissue culture that express an endogenous protein from which the peptide is derived. The procedure requires a monoclonal antibody with the ability to distinguish MHC class I molecules presenting the peptide of interest from other peptide-MHC complexes. Fluorescence signal measured on antibody-labeled cells can be compared to fluorescent-calibrated beads to determine the relative number of antibodies bound to the cell surface and hence the number of specific peptide-MHC complexes expressed by the cell. As new monoclonal antibodies with TCR-like specificity for peptide-MHC complexes are created, this method will be helpful in quantifying the exact numbers of complexes generated by cell types and relating these numbers to physiological outcomes of T cell activation.
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Affiliation(s)
- Brian P Dolan
- Department of Biomedical Sciences, Carson College of Veterinary Medicine, Oregon State University, Corvallis, OR, USA.
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Zhai J, Ding M, Yang T, Zuo B, Weng Z, Zhao Y, He J, Wu Q, Ruan C, He Y. Flow cytometric immunobead assay for quantitative detection of platelet autoantibodies in immune thrombocytopenia patients. J Transl Med 2017; 15:214. [PMID: 29061180 PMCID: PMC5654144 DOI: 10.1186/s12967-017-1317-2] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.0] [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: 07/13/2017] [Accepted: 10/12/2017] [Indexed: 05/16/2023] Open
Abstract
BACKGROUND Platelet autoantibody detection is critical for immune thrombocytopenia (ITP) diagnosis and prognosis. Therefore, we aimed to establish a quantitative flow cytometric immunobead assay (FCIA) for ITP platelet autoantibodies evaluation. METHODS Capture microbeads coupled with anti-GPIX, -GPIb, -GPIIb, -GPIIIa and P-selectin antibodies were used to bind the platelet-bound autoantibodies complex generated from plasma samples of 250 ITP patients, 163 non-ITP patients and 243 healthy controls, a fluorescein isothiocyanate (FITC)-conjugated secondary antibody was the detector reagent and mean fluorescence intensity (MFI) signals were recorded by flow cytometry. Intra- and inter-assay variations of the quantitative FCIA assay were assessed. Comparisons of the specificity, sensitivity and accuracy between quantitative and qualitative FCIA or monoclonal antibody immobilization of platelet antigen (MAIPA) assay were performed. Finally, treatment process was monitored by our quantitative FCIA in 8 newly diagnosed ITPs. RESULTS The coefficient of variations (CV) of the quantitative FCIA assay were respectively 9.4, 3.8, 5.4, 5.1 and 5.8% for anti-GPIX, -GPIb, -GPIIIa, -GPIIb and -P-selectin autoantibodies. Elevated levels of autoantibodies against platelet glycoproteins GPIX, GPIb, GPIIIa, GPIIb and P-selectin were detected by our quantitative FCIA in ITP patients compared to non-ITP patients or healthy controls. The sensitivity, specificity and accuracy of our quantitative assay were respectively 73.13, 81.98 and 78.65% when combining all 5 autoantibodies, while the sensitivity, specificity and accuracy of MAIPA assay were respectively 41.46, 90.41 and 72.81%. CONCLUSIONS A quantitative FCIA assay was established. Reduced levels of platelet autoantibodies could be confirmed by our quantitative FCIA in ITP patients after corticosteroid treatment. Our quantitative assay is not only good for ITP diagnosis but also for ITP treatment monitoring.
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Affiliation(s)
- Juping Zhai
- Ministry of Health Key Laboratory of Thrombosis and Hemostasis, Jiangsu Institute of Hematology, the First Affiliated Hospital of Soochow University, 188 Shizi St, Suzhou, 215006, Jiangsu, China
| | - Mengyuan Ding
- Ministry of Health Key Laboratory of Thrombosis and Hemostasis, Jiangsu Institute of Hematology, the First Affiliated Hospital of Soochow University, 188 Shizi St, Suzhou, 215006, Jiangsu, China
| | - Tianjie Yang
- Ministry of Health Key Laboratory of Thrombosis and Hemostasis, Jiangsu Institute of Hematology, the First Affiliated Hospital of Soochow University, 188 Shizi St, Suzhou, 215006, Jiangsu, China
| | - Bin Zuo
- Cyrus Tang Hematology Center and Ministry of Education Engineering Center of Hematological Disease, and the Collaborative Innovation Center of Hematology, Soochow University, Suzhou, 215006, China
| | - Zhen Weng
- Cyrus Tang Hematology Center and Ministry of Education Engineering Center of Hematological Disease, and the Collaborative Innovation Center of Hematology, Soochow University, Suzhou, 215006, China
| | - Yunxiao Zhao
- Ministry of Health Key Laboratory of Thrombosis and Hemostasis, Jiangsu Institute of Hematology, the First Affiliated Hospital of Soochow University, 188 Shizi St, Suzhou, 215006, Jiangsu, China
| | - Jun He
- Ministry of Health Key Laboratory of Thrombosis and Hemostasis, Jiangsu Institute of Hematology, the First Affiliated Hospital of Soochow University, 188 Shizi St, Suzhou, 215006, Jiangsu, China
| | - Qingyu Wu
- Cyrus Tang Hematology Center and Ministry of Education Engineering Center of Hematological Disease, and the Collaborative Innovation Center of Hematology, Soochow University, Suzhou, 215006, China
| | - Changgeng Ruan
- Ministry of Health Key Laboratory of Thrombosis and Hemostasis, Jiangsu Institute of Hematology, the First Affiliated Hospital of Soochow University, 188 Shizi St, Suzhou, 215006, Jiangsu, China
| | - Yang He
- Ministry of Health Key Laboratory of Thrombosis and Hemostasis, Jiangsu Institute of Hematology, the First Affiliated Hospital of Soochow University, 188 Shizi St, Suzhou, 215006, Jiangsu, China.
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Chen S, Weddell J, Gupta P, Conard G, Parkin J, Imoukhuede PI. qFlow Cytometry-Based Receptoromic Screening: A High-Throughput Quantification Approach Informing Biomarker Selection and Nanosensor Development. Methods Mol Biol 2017; 1570:117-38. [PMID: 28238133 DOI: 10.1007/978-1-4939-6840-4_8] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/01/2023]
Abstract
Nanosensor-based detection of biomarkers can improve medical diagnosis; however, a critical factor in nanosensor development is deciding which biomarker to target, as most diseases present several biomarkers. Biomarker-targeting decisions can be informed via an understanding of biomarker expression. Currently, immunohistochemistry (IHC) is the accepted standard for profiling biomarker expression. While IHC provides a relative mapping of biomarker expression, it does not provide cell-by-cell readouts of biomarker expression or absolute biomarker quantification. Flow cytometry overcomes both these IHC challenges by offering biomarker expression on a cell-by-cell basis, and when combined with calibration standards, providing quantitation of biomarker concentrations: this is known as qFlow cytometry. Here, we outline the key components for applying qFlow cytometry to detect biomarkers within the angiogenic vascular endothelial growth factor receptor family. The key aspects of the qFlow cytometry methodology include: antibody specificity testing, immunofluorescent cell labeling, saturation analysis, fluorescent microsphere calibration, and quantitative analysis of both ensemble and cell-by-cell data. Together, these methods enable high-throughput quantification of biomarker expression.
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Tembhare PR, Marti G, Wiestner A, Degheidy H, Farooqui M, Kreitman RJ, Jasper GA, Yuan CM, Liewehr D, Venzon D, Stetler-Stevenson M. Quantification of expression of antigens targeted by antibody-based therapy in chronic lymphocytic leukemia. Am J Clin Pathol 2013; 140:813-8. [PMID: 24225748 DOI: 10.1309/ajcpyfq4xmgjd6ti] [Citation(s) in RCA: 15] [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] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022] Open
Abstract
OBJECTIVES Anti-CD20 (rituximab), anti-CD52 (alemtuzumab), anti-CD22 (BL22, HA22), and anti-CD25 (Oncotac) are therapeutic options that are the mainstay or in preclinical development for the treatment of chronic lymphocytic leukemia (CLL). Studies suggest that levels of surface antigen expression may affect response to monoclonal antibody-based therapy. METHODS Using the flow cytometric Quantibrite method (BD Biosciences, San Jose, CA) to determine antibodies bound per cell, we quantified the levels of surface expression of CD20, CD22, CD25, and CD52 in CLL cells from 28 untreated patients. RESULTS The CLL cells in all cases expressed CD20, CD22, and CD52 but 4 (14%) cases were negative for CD25. Although the ranking of levels of expression from highest to lowest was CD52, CD20, CD22, and CD25, the level of antigen expression on any specific case could not be accurately predicted. CONCLUSIONS Quantification of antigens might be useful in evaluating new antigens to target for therapy and may provide a systematic approach to selecting individualized therapy in CLL.
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Affiliation(s)
- Prashant R. Tembhare
- Flow Cytometry Unit, Laboratory of Pathology, Center for Cancer Research, National Cancer Institute, National Institutes of Health, Bethesda, MD
| | - Gerald Marti
- Center for Biologics Evaluation and Research, Food and Drug Administration, Silver Spring, MD
| | - Adrian Wiestner
- Hematology Branch, National Heart, Lung, and Blood Institute, National Institutes of Health, Bethesda, MD
| | - Heba Degheidy
- Center for Biologics Evaluation and Research, Food and Drug Administration, Silver Spring, MD
| | - Mohammed Farooqui
- Hematology Branch, National Heart, Lung, and Blood Institute, National Institutes of Health, Bethesda, MD
| | - Robert J. Kreitman
- Laboratory of Molecular Biology, Center for Cancer Research, National Cancer Institute, National Institutes of Health, Bethesda, MD
| | - Gregory A. Jasper
- Flow Cytometry Unit, Laboratory of Pathology, Center for Cancer Research, National Cancer Institute, National Institutes of Health, Bethesda, MD
| | - Constance M. Yuan
- Flow Cytometry Unit, Laboratory of Pathology, Center for Cancer Research, National Cancer Institute, National Institutes of Health, Bethesda, MD
| | - David Liewehr
- Biostatistics and Data Management Section, Center for Cancer Research, National Cancer Institute, National Institutes of Health, Bethesda, MD
| | - David Venzon
- Biostatistics and Data Management Section, Center for Cancer Research, National Cancer Institute, National Institutes of Health, Bethesda, MD
| | - Maryalice Stetler-Stevenson
- Flow Cytometry Unit, Laboratory of Pathology, Center for Cancer Research, National Cancer Institute, National Institutes of Health, Bethesda, MD
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