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Song L, Zhang D, Wang H, Xia X, Huang W, Gonzales J, Via LE, Wang D. Automated quantitative assay of fibrosis characteristics in tuberculosis granulomas. Front Microbiol 2024; 14:1301141. [PMID: 38235425 PMCID: PMC10792068 DOI: 10.3389/fmicb.2023.1301141] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/24/2023] [Accepted: 11/06/2023] [Indexed: 01/19/2024] Open
Abstract
Introduction Granulomas, the pathological hallmark of Mycobacterium tuberculosis (Mtb) infection, are formed by different cell populations. Across various stages of tuberculosis conditions, most granulomas are classical caseous granulomas. They are composed of a necrotic center surrounded by multilayers of histocytes, with the outermost layer encircled by fibrosis. Although fibrosis characterizes the architecture of granulomas, little is known about the detailed parameters of fibrosis during this process. Methods In this study, samples were collected from patients with tuberculosis (spanning 16 organ types), and Mtb-infected marmosets and fibrotic collagen were characterized by second harmonic generation (SHG)/two-photon excited fluorescence (TPEF) microscopy using a stain-free, fully automated analysis program. Results Histopathological examination revealed that most granulomas share common features, including necrosis, solitary and compact structure, and especially the presence of multinuclear giant cells. Masson's trichrome staining showed that different granuloma types have varying degrees of fibrosis. SHG imaging uncovered a higher proportion (4%~13%) of aggregated collagens than of disseminated type collagens (2%~5%) in granulomas from matched tissues. Furthermore, most of the aggregated collagen presented as short and thick clusters (200~620 µm), unlike the long and thick (200~300 µm) disseminated collagens within the matched tissues. Matrix metalloproteinase-9, which is involved in fibrosis and granuloma formation, was strongly expressed in the granulomas in different tissues. Discussion Our data illustrated that different tuberculosis granulomas have some degree of fibrosis in which collagen strings are short and thick. Moreover, this study revealed that the SHG imaging program could contribute to uncovering the fibrosis characteristics of tuberculosis granulomas.
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Affiliation(s)
- Li Song
- The First College of Clinical Medical Science, China Three Gorges University, Yichang, China
- Yichang Central People’s Hospital, Yichang, China
- Hubei Key Laboratory of Tumor Microenvironment and Immunotherapy, College of Basic Medical Sciences, China Three Gorges University, Yichang, China
- Institute of Infection and Inflammation, China Three Gorges University, Yichang, China
| | - Ding Zhang
- The First College of Clinical Medical Science, China Three Gorges University, Yichang, China
- Yichang Central People’s Hospital, Yichang, China
- Hubei Key Laboratory of Tumor Microenvironment and Immunotherapy, College of Basic Medical Sciences, China Three Gorges University, Yichang, China
- Institute of Infection and Inflammation, China Three Gorges University, Yichang, China
| | - Hankun Wang
- The First College of Clinical Medical Science, China Three Gorges University, Yichang, China
- Yichang Central People’s Hospital, Yichang, China
- Hubei Key Laboratory of Tumor Microenvironment and Immunotherapy, College of Basic Medical Sciences, China Three Gorges University, Yichang, China
- Institute of Infection and Inflammation, China Three Gorges University, Yichang, China
| | - Xuan Xia
- The First College of Clinical Medical Science, China Three Gorges University, Yichang, China
- Yichang Central People’s Hospital, Yichang, China
- Hubei Key Laboratory of Tumor Microenvironment and Immunotherapy, College of Basic Medical Sciences, China Three Gorges University, Yichang, China
- Institute of Infection and Inflammation, China Three Gorges University, Yichang, China
| | - Weifeng Huang
- The First College of Clinical Medical Science, China Three Gorges University, Yichang, China
- Yichang Central People’s Hospital, Yichang, China
- Hubei Key Laboratory of Tumor Microenvironment and Immunotherapy, College of Basic Medical Sciences, China Three Gorges University, Yichang, China
- Institute of Infection and Inflammation, China Three Gorges University, Yichang, China
| | - Jacqueline Gonzales
- Tuberculosis Research Section, Laboratory of Clinical Infectious Diseases, Division of Intramural Research, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Bethesda, MD, United States
| | - Laura E. Via
- Tuberculosis Research Section, Laboratory of Clinical Infectious Diseases, Division of Intramural Research, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Bethesda, MD, United States
- Institute of Infectious Disease and Molecular Medicine, University of Cape Town, Cape Town, South Africa
| | - Decheng Wang
- The First College of Clinical Medical Science, China Three Gorges University, Yichang, China
- Yichang Central People’s Hospital, Yichang, China
- Hubei Key Laboratory of Tumor Microenvironment and Immunotherapy, College of Basic Medical Sciences, China Three Gorges University, Yichang, China
- Institute of Infection and Inflammation, China Three Gorges University, Yichang, China
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Wu G, Xie B, Lu C, Chen C, Zhou J, Deng Z. microRNA-30a attenuates TGF-β1-induced activation of pulmonary fibroblast cell by targeting FAP-α. J Cell Mol Med 2020; 24:3745-3750. [PMID: 31991519 PMCID: PMC7131934 DOI: 10.1111/jcmm.15020] [Citation(s) in RCA: 14] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/16/2019] [Revised: 10/20/2019] [Accepted: 12/16/2019] [Indexed: 01/14/2023] Open
Abstract
Idiopathic interstitial pulmonary fibrosis is a common diffuse interstitial lung disease and has poor prognosis. And one of the pathological features of it is persistent fibroblast activation. It was reported that microRNA‐30a was down‐regulated in bronchoalveolar lavage fluid from idiopathic pulmonary fibrosis patients. But whether miR‐30a is involved in fibroblast activation and its specific mechanism is unclear. In this study, we aimed to investigate the role of miR‐30a in fibroblast activation induced by TGF‐β1. We found miR‐30a could targetedly suppress FAP‐α expression. In MRC5 cells, miR‐30a was not only involved in regulating the expression of FAP‐α, col1a and α‐SMA induced by TGF‐β1 but also had a role in cell proliferation with or without TGF‐β1 treatment via regulating FAP‐α expression. Thus, the results indicated that miR‐30a alleviated fibroblast activation by regulating the expression of FAP‐α.
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Affiliation(s)
- Geting Wu
- Department of Pathology, Xiangya Hospital, Central South University, Changsha, China
| | - Bin Xie
- Department of Pathology, Xiangya Hospital, Central South University, Changsha, China
| | - Can Lu
- Department of Pathology, Xiangya Hospital, Central South University, Changsha, China
| | - Chen Chen
- Department of Pathology, Xiangya Hospital, Central South University, Changsha, China.,Department of Pathology, School of Basic Medicine, Central South University, Changsha, China
| | - Jianhua Zhou
- Department of Pathology, Xiangya Hospital, Central South University, Changsha, China.,Department of Pathology, School of Basic Medicine, Central South University, Changsha, China
| | - Zhenghao Deng
- Department of Pathology, Xiangya Hospital, Central South University, Changsha, China.,Department of Pathology, School of Basic Medicine, Central South University, Changsha, China
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3
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Argollo M, Gilardi D, Roda G, Fiorino G, Peyrin-Biroulet L, Danese S. Anti-fibrotic Drugs for Crohn’s Disease: Ready for Prime Time? Curr Pharm Des 2019; 25:47-56. [DOI: 10.2174/1381612825666190308100844] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/26/2019] [Accepted: 03/01/2019] [Indexed: 12/17/2022]
Abstract
Intestinal fibrosis, driven by chronic inflammation in Crohn’s disease, can be defined as an excessive
accumulation of extracellular matrix in the affected gut segment ultimately leading to an impaired wound healing
and cumulative tissue damage, possibly resulting in organ dysfunction, formation of stenotic lesions and necessity
of surgical intervention. Despite continuous advances in developing novel treatment modalities targeting different
pathways to control chronic gut inflammation in CD, no effective anti-fibrotic agents have been released, to date.
Thus, a better understanding of the molecular and cellular mechanisms underlying intestinal fibrosis is key to
move this area of investigation forward.
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Affiliation(s)
- Marjorie Argollo
- IBD Centre, Humanitas Clinical and Research Centre, Rozzano, Milan, Italy
| | - Daniela Gilardi
- IBD Centre, Humanitas Clinical and Research Centre, Rozzano, Milan, Italy
| | - Giulia Roda
- IBD Centre, Humanitas Clinical and Research Centre, Rozzano, Milan, Italy
| | - Gionata Fiorino
- IBD Centre, Humanitas Clinical and Research Centre, Rozzano, Milan, Italy
| | - Laurent Peyrin-Biroulet
- Department of Gastroenterology and Inserm U954, Nancy University Hospital, Lorraine University, Vandoeuvre, France
| | - Silvio Danese
- IBD Centre, Humanitas Clinical and Research Centre, Rozzano, Milan, Italy
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4
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Truffi M, Sorrentino L, Monieri M, Fociani P, Mazzucchelli S, Bonzini M, Zerbi P, Sampietro GM, Di Sabatino A, Corsi F. Inhibition of Fibroblast Activation Protein Restores a Balanced Extracellular Matrix and Reduces Fibrosis in Crohn's Disease Strictures Ex Vivo. Inflamm Bowel Dis 2018; 24:332-345. [PMID: 29361086 DOI: 10.1093/ibd/izx008] [Citation(s) in RCA: 38] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/04/2017] [Indexed: 01/13/2023]
Abstract
BACKGROUND Crohn's disease (CD) is a chronic bowel inflammation that ultimately leads to fibrosis, for which medical therapy is currently unavailable. Fibrotic strictures in CD are characterized by excessive extracellular matrix (ECM) deposition, altered balance between matrix metalloproteinases (MMPs) and their tissue inhibitors (TIMPs), and overexpression of fibroblast activation protein (FAP), a marker of active fibroblasts. Here we investigated the role of FAP-targeted therapy in ECM remodeling in CD strictures ex vivo. METHODS Bowel specimens were obtained from stenotic and nonstenotic ileal segments from 30 patients with fibrostenotic CD undergoing surgery. FAP expression was evaluated in isolated mucosal myofibroblasts by immunoblotting and flow cytometry. Bowel tissue cultures were treated with anti-FAP antibody, and soluble collagen, TIMP-1, and MMPs were measured in tissue culture supernatants by immunoblotting. Anti-FAP-treated myofibroblasts were analyzed for TIMP-1 expression by immunoblotting, for migratory potential by wound healing assay, and for apoptosis by Annexin V staining. RESULTS Myofibroblasts from stenotic CD mucosa showed upregulation of FAP expression when compared with nonstenotic mucosa. Treatment of stenotic tissues with anti-FAP antibody induced a dose-dependent decrease in collagen production, particularly affecting type I collagen. The treatment also reduced TIMP-1 production in CD strictures, without altering MMP-3 and MMP-12 secretion. Accordingly, anti-FAP treatment inhibited TIMP-1 expression in stenotic CD myofibroblasts and enhanced myofibroblast migration without affecting survival. CONCLUSIONS FAP inhibition reduced type I collagen and TIMP-1 production by CD strictures ex vivo without compromising uninvolved bowel areas. These results suggest that targeting FAP could reconstitute ECM homeostasis in fibrostenotic CD.
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Affiliation(s)
- Marta Truffi
- Department of Biomedical and Clinical Sciences "L. Sacco", University of Milan, Milan, Italy
| | - Luca Sorrentino
- Department of Biomedical and Clinical Sciences "L. Sacco", University of Milan, Milan, Italy
| | - Matteo Monieri
- Department of Biomedical and Clinical Sciences "L. Sacco", University of Milan, Milan, Italy
| | - Paolo Fociani
- Department of Pathology, IBD Unit, ASST Fatebenefratelli Sacco, Luigi Sacco University Hospital, Milan, Italy
| | - Serena Mazzucchelli
- Department of Biomedical and Clinical Sciences "L. Sacco", University of Milan, Milan, Italy
| | - Matteo Bonzini
- Department of Clinical Sciences and Community Health, University of Milan, Milan, Italy
| | - Pietro Zerbi
- Department of Biomedical and Clinical Sciences "L. Sacco", University of Milan, Milan, Italy.,Department of Pathology, IBD Unit, ASST Fatebenefratelli Sacco, Luigi Sacco University Hospital, Milan, Italy
| | - Gianluca M Sampietro
- Department of Surgery, IBD Unit, ASST Fatebenefratelli Sacco, Luigi Sacco University Hospital, Milan, Italy
| | - Antonio Di Sabatino
- First Department of Internal Medicine, St. Matteo Hospital Foundation, University of Pavia, Pavia, Italy
| | - Fabio Corsi
- Department of Biomedical and Clinical Sciences "L. Sacco", University of Milan, Milan, Italy.,Surgery Department, Breast Unit, ICS Maugeri S.p.A. SBPavia, Italy.,Nanomedicine laboratory, ICS Maugeri S.p.A. SB, Italy, Italy
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5
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Huang T, Wang H, Chen NG, Frentzen A, Minev B, Szalay AA. Expression of anti-VEGF antibody together with anti-EGFR or anti-FAP enhances tumor regression as a result of vaccinia virotherapy. MOLECULAR THERAPY-ONCOLYTICS 2015; 2:15003. [PMID: 27119102 PMCID: PMC4782963 DOI: 10.1038/mto.2015.3] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 12/12/2014] [Accepted: 12/20/2014] [Indexed: 01/09/2023]
Abstract
The tumor microenvironment plays an important role in tumor growth and progression. Here we demonstrate that vaccinia virus-mediated, constitutively expressed intratumoral antibodies against vascular endothelial growth factor (VEGF), epidermal growth factor receptor (EGFR), and fibroblast activation protein (FAP) significantly improved tumor regression and oncolytic virotherapy through suppression of angiogenesis, cell proliferation, and stromagenesis in virus-colonized tumors. In contrast to the tumor growth inhibition by the three tumor growth-inhibiting antibodies individually, when two of the three antibodies were expressed simultaneously by single vaccinia virus strains tumor regression was further enhanced. These findings strongly indicate that interference with the two tumor growth-stimulating mechanisms did in fact result in enhanced therapeutic efficacy in tumor xenograft models and may lead to an effective therapy in patients with cancer.
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Affiliation(s)
- Ting Huang
- Department of Biochemistry, Rudolph Virchow Center for Experimental Biomedicine, Institute for Molecular Infection Biology, University of Würzburg , Würzburg, Germany
| | - Huiqiang Wang
- Genelux Corporation, San Diego Science Center , San Diego, California, USA
| | - Nanhai G Chen
- Genelux Corporation, San Diego Science Center, San Diego, California, USA; Department of Radiation Medicine and Applied Sciences, Rebecca & John Moores Comprehensive Cancer Center, University of California, San Diego, California, USA
| | - Alexa Frentzen
- Genelux Corporation, San Diego Science Center , San Diego, California, USA
| | - Boris Minev
- Genelux Corporation, San Diego Science Center, San Diego, California, USA; Department of Radiation Medicine and Applied Sciences, Rebecca & John Moores Comprehensive Cancer Center, University of California, San Diego, California, USA; Division of Neurosurgery, University of California, San Diego, California, USA
| | - Aladar A Szalay
- Department of Biochemistry, Rudolph Virchow Center for Experimental Biomedicine, Institute for Molecular Infection Biology, University of Würzburg, Würzburg, Germany; Genelux Corporation, San Diego Science Center, San Diego, California, USA; Department of Radiation Medicine and Applied Sciences, Rebecca & John Moores Comprehensive Cancer Center, University of California, San Diego, California, USA
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7
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Cox G. Biological applications of second harmonic imaging. Biophys Rev 2011; 3:131. [PMID: 28510062 DOI: 10.1007/s12551-011-0052-9] [Citation(s) in RCA: 29] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/26/2011] [Accepted: 07/04/2011] [Indexed: 11/26/2022] Open
Abstract
Second Harmonic Generation (SHG) microscopy dates back to 1974, but effective biological use of the technique has a history of barely 10 years. It is now widely used to image collagen in many different applications, and is becoming useful for imaging myosin and some polysaccharides. A separate line on research has focussed on SHG dyes, which can provide high-speed indication of membrane potential and are now in use in neurobiology. This review looks at the progress to date in these different fields.
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Affiliation(s)
- Guy Cox
- Australian Centre for Microscopy and Microanalysis, University of Sydney, NSW, 2006, Australia.
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8
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Fibroblast activation protein-α promotes tumor growth and invasion of breast cancer cells through non-enzymatic functions. Clin Exp Metastasis 2011; 28:567-79. [PMID: 21604185 DOI: 10.1007/s10585-011-9392-x] [Citation(s) in RCA: 82] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/01/2010] [Accepted: 04/23/2011] [Indexed: 10/25/2022]
Abstract
Fibroblast activation protein-α (FAP) is a cell surface, serine protease of the post-prolyl peptidase family that is expressed in human breast cancer but not in normal tissues. Previously, we showed that FAP expression increased tumor growth rates in a mouse model of human breast cancer. Here the role of the proteolytic activities of FAP in promoting tumor growth, matrix degradation and invasion was investigated. Mammary fat pads of female SCID mice were inoculated with breast cancer cells that express FAP and the mice treated with normal saline or Val-boroPro (talabostat); Glu-boroPro (PT-630); or 1-[[(3-hydroxy-1-adamantyl)amino]acetyl]-2-cyano-(S)-pyrrolidine (LAF-237) that inhibit prolyl peptidases. Other mice were injected with breast cancer cells expressing a catalytically inactive mutant of FAP and did not receive inhibitor treatment. PT-630 and LAF-237 did not slow growth of tumors produced by any of the three cell lines expressing FAP. Talabostat slightly decreased the growth rates of the FAP-expressing tumors but because PT-630 and LAF-237 did not, the growth retardation was likely not related to the inhibition of FAP or the related post-prolyl peptidase dipeptidyl peptidase IV. Breast cancer cells expressing a catalytically inactive mutant of FAP (FAP(S624A)) also produced tumors that grew rapidly. In vitro studies revealed that cells expressing wild type FAP or FAP(S624A) degrade extracellular matrix (ECM) more extensively, accumulate higher levels of matrix metalloproteinase-9 (MMP-9) in conditioned medium, are more invasive in type I collagen gels, and have altered signaling compared to control transfectants that do not express FAP and form slow growing tumors. We conclude that the proteolytic activity of FAP participates in matrix degradation, but other functions of the protein stimulate increased tumor growth.
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He Y, Kang CH, Xu S, Tuo X, Trasti S, Tai DCS, Raja AM, Peng Q, So PTC, Rajapakse JC, Welsch R, Yu H. Toward surface quantification of liver fibrosis progression. JOURNAL OF BIOMEDICAL OPTICS 2010; 15:056007. [PMID: 21054101 DOI: 10.1117/1.3490414] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/30/2023]
Abstract
Monitoring liver fibrosis progression by liver biopsy is important for certain treatment decisions, but repeated biopsy is invasive. We envision redefinition or elimination of liver biopsy with surface scanning of the liver with minimally invasive optical methods. This would be possible only if the information contained on or near liver surfaces accurately reflects the liver fibrosis progression in the liver interior. In our study, we acquired the second-harmonic generation and two-photon excitation fluorescence microscopy images of liver tissues from bile duct-ligated rat model of liver fibrosis. We extracted morphology-based features, such as total collagen, collagen in bile duct areas, bile duct proliferation, and areas occupied by remnant hepatocytes, and defined the capsule and subcapsular regions on the liver surface based on image analysis of features. We discovered a strong correlation between the liver fibrosis progression on the anterior surface and interior in both liver lobes, where biopsy is typically obtained. The posterior surface exhibits less correlation with the rest of the liver. Therefore, scanning the anterior liver surface would obtain similar information to that obtained from biopsy for monitoring liver fibrosis progression.
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Affiliation(s)
- Yuting He
- Singapore-MIT Alliance, E4-04-10, 4 Engineering Drive 3, Singapore 117576
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Tai DCS, Tan N, Xu S, Kang CH, Chia SM, Cheng CL, Wee A, Wei CL, Raja AM, Xiao G, Chang S, Rajapakse JC, So PTC, Tang HH, Chen CS, Yu H. Fibro-C-Index: comprehensive, morphology-based quantification of liver fibrosis using second harmonic generation and two-photon microscopy. JOURNAL OF BIOMEDICAL OPTICS 2009; 14:044013. [PMID: 19725725 DOI: 10.1117/1.3183811] [Citation(s) in RCA: 58] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/26/2023]
Abstract
We develop a standardized, fully automated, quantification system for liver fibrosis assessment using second harmonic generation microscopy and a morphology-based quantification algorithm. Liver fibrosis is associated with an abnormal increase in collagen as a result of chronic liver diseases. Histopathological scoring is the most commonly used method for liver fibrosis assessment, where a liver biopsy is stained and scored by experienced pathologists. Due to the intrinsic limited sensitivity and operator-dependent variations, there exist high inter- and intraobserver discrepancies. We validate our quantification system, Fibro-C-Index, with a comprehensive animal study and demonstrate its potential application in clinical diagnosis to reduce inter- and intraobserver discrepancies.
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Affiliation(s)
- Dean C S Tai
- Institute of Bioengineering and Nanotechnology, The Nanos #04-01, 31 Biopolis Way, Singapore, 138669.
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Reshak AH. Second harmonic generation from thick leaves using the two-photon laser scanning microscope. Micron 2009; 40:455-62. [DOI: 10.1016/j.micron.2008.12.008] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/30/2008] [Revised: 12/18/2008] [Accepted: 12/19/2008] [Indexed: 11/25/2022]
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12
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Second harmonic imaging of chloroplasts using the two-photon laser scanning microscope. Micron 2009; 40:378-85. [DOI: 10.1016/j.micron.2008.09.007] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/18/2008] [Revised: 09/28/2008] [Accepted: 09/29/2008] [Indexed: 11/21/2022]
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13
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Sun W, Chang S, Tai DCS, Tan N, Xiao G, Tang H, Yu H. Nonlinear optical microscopy: use of second harmonic generation and two-photon microscopy for automated quantitative liver fibrosis studies. JOURNAL OF BIOMEDICAL OPTICS 2008; 13:064010. [PMID: 19123657 DOI: 10.1117/1.3041159] [Citation(s) in RCA: 86] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/18/2023]
Abstract
Liver fibrosis is associated with an abnormal increase in an extracellular matrix in chronic liver diseases. Quantitative characterization of fibrillar collagen in intact tissue is essential for both fibrosis studies and clinical applications. Commonly used methods, histological staining followed by either semiquantitative or computerized image analysis, have limited sensitivity, accuracy, and operator-dependent variations. The fibrillar collagen in sinusoids of normal livers could be observed through second-harmonic generation (SHG) microscopy. The two-photon excited fluorescence (TPEF) images, recorded simultaneously with SHG, clearly revealed the hepatocyte morphology. We have systematically optimized the parameters for the quantitative SHG/TPEF imaging of liver tissue and developed fully automated image analysis algorithms to extract the information of collagen changes and cell necrosis. Subtle changes in the distribution and amount of collagen and cell morphology are quantitatively characterized in SHG/TPEF images. By comparing to traditional staining, such as Masson's trichrome and Sirius red, SHG/TPEF is a sensitive quantitative tool for automated collagen characterization in liver tissue. Our system allows for enhanced detection and quantification of sinusoidal collagen fibers in fibrosis research and clinical diagnostics.
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Affiliation(s)
- Wanxin Sun
- Institute of Bioengineering and Nanotechnology, The Nanos #4-01, 31 Biopolis Way, Singapore, Singapore 138669
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Abstract
Molecules that have no center of symmetry are able to convert light to its second harmonic, at twice the frequency and half the wavelength. This only happens with any efficiency at very high light intensities such as are given by a pulsed laser, and because the efficiency of the process depends on the square of the intensity, it will be focal plane selective in exactly the same way as two-photon excitation of fluorescence. Because of its unusual molecular structure and its high degree of crystallinity, collagen is, by far, the strongest source of second harmonics in animal tissue. Because collagen is also the most important structural protein in the mammalian body, this provides a very useful imaging tool for studying its distribution. No energy is lost in second-harmonic imaging, so the image will not fade, and because it is at a shorter wavelength than can be excited by two-photon fluorescence, it can be separated easily from multiple fluorescent probes. It is already proving useful in imaging collagen with high sensitivity in various tissues, including cirrhotic liver, normal and carious teeth, and surgical repair of tendons.
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Affiliation(s)
- Guy Cox
- Electron Microscope Unit, University of Sydney, Australia
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Gorrell MD. Dipeptidyl peptidase IV and related enzymes in cell biology and liver disorders. Clin Sci (Lond) 2005; 108:277-92. [PMID: 15584901 DOI: 10.1042/cs20040302] [Citation(s) in RCA: 234] [Impact Index Per Article: 12.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023]
Abstract
DP (dipeptidyl peptidase) IV is the archetypal member of its six-member gene family. Four members of this family, DPIV, FAP (fibroblast activation protein), DP8 and DP9, have a rare substrate specificity, hydrolysis of a prolyl bond two residues from the N-terminus. The ubiquitous DPIV glycoprotein has proved interesting in the fields of immunology, endocrinology, haematology and endothelial cell and cancer biology and DPIV has become a novel target for Type II diabetes therapy. The crystal structure shows that the soluble form of DPIV comprises two domains, an alpha/beta-hydrolase domain and an eight-blade beta-propeller domain. The propeller domain contains the ADA (adenosine deaminase) binding site, a dimerization site, antibody epitopes and two openings for substrate access to the internal active site. FAP is structurally very similar to DPIV, but FAP protein expression is largely confined to diseased and damaged tissue, notably the tissue remodelling interface in chronically injured liver. DPIV has a variety of peptide substrates, the best studied being GLP-1 (glucagon-like peptide-1), NPY (neuropeptide Y) and CXCL12. The DPIV family has roles in bone marrow mobilization. The functional interactions of DPIV and FAP with extracellular matrix confer roles for these proteins in cancer biology. DP8 and DP9 are widely distributed and indirectly implicated in immune function. The DPL (DP-like) glycoproteins that lack peptidase activity, DPL1 and DPL2, are brain-expressed potassium channel modulators. Thus the six members of the DPIV gene family exhibit diverse biological roles.
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Affiliation(s)
- Mark D Gorrell
- A.W. Morrow Gastroenterology and Liver Centre at Royal Prince Alfred Hospital, Centenary Institute of Cancer Medicine and Cell Biology and Discipline of Medicine, The University of Sydney, Sydney, New South Wales, Australia.
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