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Spatiotemporal regulation of PEDF signaling by type I collagen remodeling. Proc Natl Acad Sci U S A 2020; 117:11450-11458. [PMID: 32385162 DOI: 10.1073/pnas.2004034117] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/29/2022] Open
Abstract
Dynamic remodeling of the extracellular matrix affects many cellular processes, either directly or indirectly, through the regulation of soluble ligands; however, the mechanistic details of this process remain largely unknown. Here we propose that type I collagen remodeling regulates the receptor-binding activity of pigment epithelium-derived factor (PEDF), a widely expressed secreted glycoprotein that has multiple important biological functions in tissue and organ homeostasis. We determined the crystal structure of PEDF in complex with a disulfide cross-linked heterotrimeric collagen peptide, in which the α(I) chain segments-each containing the respective PEDF-binding region (residues 930 to 938)-are assembled with an α2α1α1 staggered configuration. The complex structure revealed that PEDF specifically interacts with a unique amphiphilic sequence, KGHRGFSGL, of the type I collagen α1 chain, with its proposed receptor-binding sites buried extensively. Molecular docking demonstrated that the PEDF-binding surface of type I collagen contains the cross-link-susceptible Lys930 residue of the α1 chain and provides a good foothold for stable docking with the α1(I) N-telopeptide of an adjacent triple helix in the fibril. Therefore, the binding surface is completely inaccessible if intermolecular crosslinking between two crosslink-susceptible lysyl residues, Lys9 in the N-telopeptide and Lys930, is present. These structural analyses demonstrate that PEDF molecules, once sequestered around newly synthesized pericellular collagen fibrils, are gradually liberated as collagen crosslinking increases, making them accessible for interaction with their target cell surface receptors in a spatiotemporally regulated manner.
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Lupo G, Cambria MT, Olivieri M, Rocco C, Caporarello N, Longo A, Zanghì G, Salmeri M, Foti MC, Anfuso CD. Anti-angiogenic effect of quercetin and its 8-methyl pentamethyl ether derivative in human microvascular endothelial cells. J Cell Mol Med 2019; 23:6565-6577. [PMID: 31369203 PMCID: PMC6787496 DOI: 10.1111/jcmm.14455] [Citation(s) in RCA: 22] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/30/2019] [Revised: 05/03/2019] [Accepted: 05/17/2019] [Indexed: 12/27/2022] Open
Abstract
Angiogenesis is involved in many pathological states such as progression of tumours, retinopathy of prematurity and diabetic retinopathy. The latter is a more complex diabetic complication in which neurodegeneration plays a significant role and a leading cause of blindness. The vascular endothelial growth factor (VEGF) is a powerful pro‐angiogenic factor that acts through three tyrosine kinase receptors (VEGFR‐1, VEGFR‐2 and VEGFR‐3). In this work we studied the anti‐angiogenic effect of quercetin (Q) and some of its derivates in human microvascular endothelial cells, as a blood retinal barrier model, after stimulation with VEGF‐A. We found that a permethylated form of Q, namely 8MQPM, more than the simple Q, is a potent inhibitor of angiogenesis both in vitro and ex vivo. Our results showed that these compounds inhibited cell viability and migration and disrupted the formation of microvessels in rabbit aortic ring. The addition of Q and more significantly 8MQPM caused recoveries or completely re‐establish the transendothelial electrical resistance (TEER) to the control values and suppressed the activation of VEGFR2 downstream signalling molecules such as AKT, extracellular signal‐regulated kinase, and c‐Jun N‐terminal kinase. Taken together, these data suggest that 8MQPM might have an important role in the contrast of angiogenesis‐related diseases.
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Affiliation(s)
- Gabriella Lupo
- Section of Medical Biochemistry, Department of Biomedical and Biotechnological Sciences (Biometec), School of Medicine, University of Catania, Catania, Italy
| | - Maria Teresa Cambria
- Section of Medical Biochemistry, Department of Biomedical and Biotechnological Sciences (Biometec), School of Medicine, University of Catania, Catania, Italy
| | - Melania Olivieri
- Section of Medical Biochemistry, Department of Biomedical and Biotechnological Sciences (Biometec), School of Medicine, University of Catania, Catania, Italy
| | - Concetta Rocco
- Institute of Biomolecular Chemistry of CNR, Catania, Italy
| | - Nunzia Caporarello
- Section of Medical Biochemistry, Department of Biomedical and Biotechnological Sciences (Biometec), School of Medicine, University of Catania, Catania, Italy
| | - Anna Longo
- Section of Medical Biochemistry, Department of Biomedical and Biotechnological Sciences (Biometec), School of Medicine, University of Catania, Catania, Italy
| | - Guido Zanghì
- Department of Surgery (CHIR), School of Medicine, University of Catania, Catania, Italy
| | - Mario Salmeri
- Section of Medical Biochemistry, Department of Biomedical and Biotechnological Sciences (Biometec), School of Medicine, University of Catania, Catania, Italy
| | - Mario C Foti
- Institute of Biomolecular Chemistry of CNR, Catania, Italy
| | - Carmelina Daniela Anfuso
- Section of Medical Biochemistry, Department of Biomedical and Biotechnological Sciences (Biometec), School of Medicine, University of Catania, Catania, Italy
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Honrubia-Gómez P, López-Garrido MP, Gil-Gas C, Sánchez-Sánchez J, Alvarez-Simon C, Cuenca-Escalona J, Perez AF, Arias E, Moreno R, Sánchez-Sánchez F, Ramirez-Castillejo C. Pedf derived peptides affect colorectal cancer cell lines resistance and tumour re-growth capacity. Oncotarget 2019; 10:2973-2986. [PMID: 31105879 PMCID: PMC6508205 DOI: 10.18632/oncotarget.26085] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/19/2018] [Accepted: 08/06/2018] [Indexed: 12/14/2022] Open
Abstract
Relapse after chemotherapy treatment depends on the cancer initiating cells (CICs). PEDF (Pigmented Epithelium Derived Factor) is an anti-angiogenic, neurotrophic and self-renewal regulator molecule, also involved in CICs biology. Acute and chronic exposition of colon cancer cell lines to CT/CTE PEDF-derived peptides decreased drug-resistance to conventional colorectal cancer treatments, such as oxaliplatin or irinotecan. We confirmed a reduction in the irinotecan and oxaliplatin IC50 doses for all tested tumour cell lines. After xenograft transplantation, CT/CTE treatments also produced a reduction in resistance to conventional chemotherapy treatments as in culture-assays. Metastatic capacity of these treated cell lines was also depleted. The PEDF signaling pathway could be a future therapeutic tool for use as an adjuvant therapy that decreases IC50 dosis, adverse effects and treatment costs. This pathway could also be involved in an increase of the time relapse in patients, decreased tumourigenicity, and decreased capacity to produce metastasis.
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Affiliation(s)
| | - María-Pilar López-Garrido
- Genética Médica, Departamento de Ciencia y Tecnología Agroforestal y Genética, IDINE, UCLM, Albacete, Spain
| | - Carmen Gil-Gas
- Stem Cell Laboratory, Departamento Ciencias Médicas, CRIB, UCLM, Albacete, Spain
| | | | - Carmen Alvarez-Simon
- Stem Cell Laboratory, Departamento Ciencias Médicas, CRIB, UCLM, Albacete, Spain
| | - Jorge Cuenca-Escalona
- Cancer Stem Cell Laboratory, HST Group, Biotechnology and V Biology Department, ETSIAAB, UPM, Madrid, Spain
| | - Ana Ferrer Perez
- Current address: Oncology Division, Hospital Obispo Polanco, Teruel, Spain
| | - Enrique Arias
- Departamento de Sistemas Informáticos, UCLM, Albacete, Spain
| | | | - Francisco Sánchez-Sánchez
- Genética Médica, Departamento de Ciencia y Tecnología Agroforestal y Genética, IDINE, UCLM, Albacete, Spain
| | - Carmen Ramirez-Castillejo
- Stem Cell Laboratory, Departamento Ciencias Médicas, CRIB, UCLM, Albacete, Spain.,Cancer Stem Cell Laboratory, HST Group, Biotechnology and V Biology Department, ETSIAAB, UPM, Madrid, Spain
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4
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Negative regulators of angiogenesis: important targets for treatment of exudative AMD. Clin Sci (Lond) 2017; 131:1763-1780. [PMID: 28679845 DOI: 10.1042/cs20170066] [Citation(s) in RCA: 38] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/20/2017] [Revised: 03/17/2017] [Accepted: 04/03/2017] [Indexed: 12/12/2022]
Abstract
Angiogenesis contributes to the pathogenesis of many diseases including exudative age-related macular degeneration (AMD). It is normally kept in check by a tightly balanced production of pro- and anti-angiogenic factors. The up-regulation of the pro-angiogenic factor, vascular endothelial growth factor (VEGF), is intimately linked to the pathogenesis of exudative AMD, and its antagonism has been effectively targeted for treatment. However, very little is known about potential changes in expression of anti-angiogenic factors and the role they play in choroidal vascular homeostasis and neovascularization associated with AMD. Here, we will discuss the important role of thrombospondins and pigment epithelium-derived factor, two major endogenous inhibitors of angiogenesis, in retinal and choroidal vascular homeostasis and their potential alterations during AMD and choroidal neovascularization (CNV). We will review the cell autonomous function of these proteins in retinal and choroidal vascular cells. We will also discuss the potential targeting of these molecules and use of their mimetic peptides for therapeutic development for exudative AMD.
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Winokur PN, Subramanian P, Bullock JL, Arocas V, Becerra SP. Comparison of two neurotrophic serpins reveals a small fragment with cell survival activity. Mol Vis 2017; 23:372-384. [PMID: 28706437 PMCID: PMC5501690] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/31/2017] [Accepted: 06/30/2017] [Indexed: 10/31/2022] Open
Abstract
PURPOSE Protease nexin-1 (PN-1), a serpin encoded by the SERPINE2 gene, has serine protease inhibitory activity and neurotrophic properties in the brain. PN-1 inhibits retinal angiogenesis; however, PN-1's neurotrophic capacities in the retina have not yet been evaluated. Pigment epithelium-derived factor (PEDF) is a serpin that exhibits neurotrophic and antiangiogenic activities but lacks protease inhibitory properties. The aim of this study is to compare PN-1 and PEDF. METHODS Sequence comparisons were performed using computer bioinformatics programs. Mouse and bovine eyes, human retina tissue, and ARPE-19 cells were used to prepare RNA and protein samples. Interphotoreceptor matrix lavage was obtained from bovine eyes. Gene expression and protein levels were evaluated with reverse-transcription PCR (RT-PCR) and western blotting, respectively. Recombinant human PN-1, a version of PN-1 referred to as PN-1[R346A] lacking serine protease inhibitory activity, and PEDF proteins were used, as well as synthetic peptides designed from PEDF and PN-1 sequences. Survival activity in serum-starved, rat-derived retinal precursor (R28) cells was assessed with terminal deoxynucleotidyl transferase (TdT) dUTP nick-end labeling (TUNEL) cell death assays. Bcl2 levels were measured with RT-PCR. RESULTS PN-1 is analogous in primary and tertiary structure to PEDF. A region in PN-1 shares homology with the neurotrophic active region of PEDF, a 17-residue region within alpha helix C. The native human retina, ARPE-19 cells, and murine RPE and retina expressed the gene for PN-1 (SERPINE2 and Serpine2 mRNA). The retina, ARPE-19 cell lysates, and bovine interphotoreceptor matrix contained PN-1 protein. The addition of PN-1, PN-1[R346A], or the 17mer peptide of PN-1 to serum-starved retina cells decreased the number of TUNEL-positive nuclei relative to the untreated cells, such as PEDF. PN-1, PN-1[R346A], and PN-1-17mer treatments increased the Bcl2 transcript levels in serum-starved cells, as seen with PEDF. CONCLUSIONS PN-1 and PEDF share structural and functional features, and expression patterns in the retina. These serpins' mechanisms of action as cell survival factors are independent of serine protease inhibition. We have identified PN-1 as a novel factor for the retina that may play a neuroprotective role in vivo, and small peptides as relevant candidates for preventing retinal degeneration.
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Affiliation(s)
- Paige N. Winokur
- NIH, NEI, Section of Protein Structure and Function, Bethesda, MD
| | | | - Jeanee L. Bullock
- NIH, NEI, Section of Protein Structure and Function, Bethesda, MD,Georgetown University, Department of Biochemistry and Molecular and Cellular Biology, Washington, DC
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Belkacemi L, Zhang SX. Anti-tumor effects of pigment epithelium-derived factor (PEDF): implication for cancer therapy. A mini-review. JOURNAL OF EXPERIMENTAL & CLINICAL CANCER RESEARCH : CR 2016; 35:4. [PMID: 26746675 PMCID: PMC4706649 DOI: 10.1186/s13046-015-0278-7] [Citation(s) in RCA: 26] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 11/09/2015] [Accepted: 12/22/2015] [Indexed: 12/22/2022]
Abstract
Pigment epithelium-derived factor (PEDF) is a secreted glycoprotein and a non-inhibitory member of the serine protease inhibitor (serpin) family. It is widely expressed in human fetal and adult tissues but its expression decreases with age and in malignant tissues. The main anti-cancer activities of PEDF derive from its dual effects, either indirectly on the tumor microenvironment (indirect antitumor action) or directly on the tumor itself (direct antitumor influence). The indirect antitumor activities of PEDF were uncovered from the early findings that it stimulates retinoblastoma cell differentiation and that additionally it possesses anti-angiogenic, anti-tumorigenic and anti-metastatic properties. The mechanisms of its direct antitumor effect, however, have not been fully elucidated. This review highlights recent progress in our understanding of the multifunctional activities of PEDF and, in particular, its anti-cancer signaling mechanisms. Additionally, we discuss the possibility of using novel phosphaplatin compounds that can upregulate PEDF expression as a chemotherapy for cancer treatment.
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Affiliation(s)
- Louiza Belkacemi
- Center for Nuclear Receptors and Cell Signaling, University of Houston, Houston, TX, 77204, USA.
| | - Shaun Xiaoliu Zhang
- Department of Biology and Biochemistry, University of Houston, Houston, TX, 77204, USA. .,Center for Nuclear Receptors and Cell Signaling, University of Houston, Houston, TX, 77204, USA.
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Conti A, Alessio M. Comparative Proteomics for the Evaluation of Protein Expression and Modifications in Neurodegenerative Diseases. INTERNATIONAL REVIEW OF NEUROBIOLOGY 2015; 121:117-52. [PMID: 26315764 DOI: 10.1016/bs.irn.2015.05.004] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/14/2022]
Abstract
Together with hypothesis-driven approaches, high-throughput differential proteomic analysis performed primarily not only in human cerebrospinal fluid and serum but also on protein content of other tissues (blood cells, muscles, peripheral nerves, etc.) has been used in the last years to investigate neurodegenerative diseases. Even if the goal for these analyses was mainly the discovery of neurodegenerative disorders biomarkers, the characterization of specific posttranslational modifications (PTMs) and the differential protein expression resulted in being very informative to better define the pathological mechanisms. In this chapter are presented and discussed the positive aspects and challenges of the outcomes of some of our investigations on neurological and neurodegenerative disease, in order to highlight the important role of protein PTMs studies in proteomics-based approaches.
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Affiliation(s)
- Antonio Conti
- Proteome Biochemistry, Division of Genetics and Cell Biology, IRCCS San Raffaele Scientific Institute, Milano, Italy
| | - Massimo Alessio
- Proteome Biochemistry, Division of Genetics and Cell Biology, IRCCS San Raffaele Scientific Institute, Milano, Italy.
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8
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PEDF and its roles in physiological and pathological conditions: implication in diabetic and hypoxia-induced angiogenic diseases. Clin Sci (Lond) 2015; 128:805-23. [PMID: 25881671 PMCID: PMC4557399 DOI: 10.1042/cs20130463] [Citation(s) in RCA: 95] [Impact Index Per Article: 10.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022]
Abstract
Pigment epithelium-derived factor (PEDF) is a broadly expressed multifunctional member of the serine proteinase inhibitor (serpin) family. This widely studied protein plays critical roles in many physiological and pathophysiological processes, including neuroprotection, angiogenesis, fibrogenesis and inflammation. The present review summarizes the temporal and spatial distribution patterns of PEDF in a variety of developing and adult organs, and discusses its functions in maintaining physiological homoeostasis. The major focus of the present review is to discuss the implication of PEDF in diabetic and hypoxia-induced angiogenesis, and the pathways mediating PEDF's effects under these conditions. Furthermore, the regulatory mechanisms of PEDF expression, function and degradation are also reviewed. Finally, the therapeutic potential of PEDF as an anti-angiogenic drug is briefly summarized.
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Xiong L, Edwards CK, Zhou L. The biological function and clinical utilization of CD147 in human diseases: a review of the current scientific literature. Int J Mol Sci 2014; 15:17411-41. [PMID: 25268615 PMCID: PMC4227170 DOI: 10.3390/ijms151017411] [Citation(s) in RCA: 146] [Impact Index Per Article: 14.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/04/2014] [Revised: 09/08/2014] [Accepted: 09/16/2014] [Indexed: 02/05/2023] Open
Abstract
CD147 or EMMPRIN is a member of the immunoglobulin superfamily in humans. It is widely expressed in human tumors and plays a central role in the progression of many cancers by stimulating the secretion of matrix metalloproteinases (MMPs) and cytokines. CD147 regulates cell proliferation, apoptosis, and tumor cell migration, metastasis and differentiation, especially under hypoxic conditions. CD147 is also important to many organ systems. This review will provide a detailed overview of the discovery, characterization, molecular structure, diverse biological functions and regulatory mechanisms of CD147 in human physiological and pathological processes. In particular, recent studies have demonstrated the potential application of CD147 not only as a phenotypic marker of activated regulatory T cells but also as a potential diagnostic marker for early-stage disease. Moreover, CD147 is recognized as an effective therapeutic target for hepatocellular carcinoma (HCC) and other cancers, and exciting clinical progress has been made in HCC treatment using CD147-directed monoclonal antibodies.
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Affiliation(s)
- Lijuan Xiong
- Central Laboratory, Navy General Hospital, Beijing 100048, China.
| | - Carl K Edwards
- National Key Laboratory of Biotherapy and Cancer Research (NKLB), West China Hospital and Medical School, Sichuan University, Chengdu 610041, China.
| | - Lijun Zhou
- Central Laboratory, Navy General Hospital, Beijing 100048, China.
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10
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Annexin A2: its molecular regulation and cellular expression in cancer development. DISEASE MARKERS 2014; 2014:308976. [PMID: 24591759 PMCID: PMC3925611 DOI: 10.1155/2014/308976] [Citation(s) in RCA: 92] [Impact Index Per Article: 9.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Subscribe] [Scholar Register] [Received: 06/29/2013] [Revised: 10/31/2013] [Accepted: 11/01/2013] [Indexed: 01/05/2023]
Abstract
Annexin A2 (ANXA2) orchestrates multiple biologic processes and clinical associations, especially in cancer progression. The structure of ANXA2 affects its cellular localization and function. However, posttranslational modification and protease-mediated N-terminal cleavage also play critical roles in regulating ANXA2. ANXA2 expression levels vary among different types of cancers. With some cancers, ANXA2 can be used for the detection and diagnosis of cancer and for monitoring cancer progression. ANXA2 is also required for drug-resistance. This review discusses the feasibility of ANXA2 which is active in cancer development and can be a therapeutic target in cancer management.
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Becerra SP, Notario V. The effects of PEDF on cancer biology: mechanisms of action and therapeutic potential. Nat Rev Cancer 2013; 13:258-71. [PMID: 23486238 PMCID: PMC3707632 DOI: 10.1038/nrc3484] [Citation(s) in RCA: 162] [Impact Index Per Article: 14.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/18/2023]
Abstract
The potent actions of pigment epithelium-derived factor (PEDF) on tumour-associated cells, and its extracellular localization and secretion, stimulated research on this multifunctional serpin. Such studies have identified several PEDF receptors and downstream signalling pathways. Known cellular PEDF responses have expanded from the initial discovery that PEDF induces retinoblastoma cell differentiation to its anti-angiogenic, antitumorigenic and antimetastatic properties. Although the diversity of PEDF activities seems to be complex, they are consistent with the varied mechanisms that regulate this multimodal factor. If PEDF is to be used for cancer management, a deeper appreciation of its many functions and mechanisms of action is needed.
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Affiliation(s)
- S Patricia Becerra
- National Eye Institute, US National Institutes of Health, Bethesda, Maryland, USA.
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12
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Sekiya A, Okano-Kosugi H, Yamazaki CM, Koide T. Pigment epithelium-derived factor (PEDF) shares binding sites in collagen with heparin/heparan sulfate proteoglycans. J Biol Chem 2011; 286:26364-74. [PMID: 21652703 DOI: 10.1074/jbc.m111.252684] [Citation(s) in RCA: 48] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
Pigment epithelium-derived factor (PEDF) is a collagen-binding protein that is abundantly distributed in various tissues, including the eye. It exhibits various biological functions, such as anti-angiogenic, neurotrophic, and neuroprotective activities. PEDF also interacts with extracellular matrix components such as collagen, heparan sulfate proteoglycans (HSPGs), and hyaluronan. The collagen-binding property has been elucidated to be important for the anti-angiogenic activity in vivo (Hosomichi, J., Yasui, N., Koide, T., Soma, K., and Morita, I. (2005) Biochem. Biophys. Res. Commun. 335, 756-761). Here, we investigated the collagen recognition mechanism by PEDF. We first narrowed down candidate PEDF-binding sequences by taking advantage of previously reported structural requirements in collagen. Subsequent searches for PEDF-binding sequences employing synthetic collagen-like peptides resulted in the identification of one of the critical binding sites for PEDF, human α1(I)(929-938) (IKGHRGFSGL). Further analysis revealed that the collagen recognition by PEDF is sequence- and conformation-specific, and the high affinity binding motif is KGXRGFXGL in the triple helix. The PEDF-binding motif significantly overlapped with the heparin/HSPG-binding motif, KGHRG(F/Y). The interaction of PEDF with collagen I was specifically competed with by heparin but not by chondroitin sulfate-C or hyaluronan. The binding sequences for PEDF and heparin/HSPG also overlapped with the covalent cross-linking sites between collagen molecules. These findings imply a functional relationship between PEDF and HSPGs during angiogenesis, and the interaction of these molecules is regulated by collagen modifications.
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Affiliation(s)
- Atsushi Sekiya
- Department of Chemistry and Biochemistry, School of Advanced Science and Engineering, Waseda University, Tokyo 169-8555, Japan
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13
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Manalo KB, Choong PFM, Becerra SP, Dass CR. Pigment epithelium-derived factor as an anticancer drug and new treatment methods following the discovery of its receptors: a patent perspective. Expert Opin Ther Pat 2011; 21:121-30. [PMID: 21204726 PMCID: PMC4026095 DOI: 10.1517/13543776.2011.545347] [Citation(s) in RCA: 24] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/05/2022]
Abstract
Traditional forms of cancer therapy, which include chemotherapy, have largely been overhauled due to the significant degree of toxicity they pose to normal, otherwise healthy tissue. It is hoped that the use of biological agents, most of which are endogenously present in the body, will lead to safer treatment outcomes, without sacrificing efficacy. The finding that pigment epithelium-derived factor (PEDF), a naturally-occurring protein, is a potent angiogenesis inhibitor has become the basis for studying the role of PEDF in tumours that are highly resistant to chemotherapy. The determination of the direct role of PEDF against cancer paves the way for understanding and developing PEDF as a novel drug. This review focuses on the patent applications behind testing the anticancer therapeutic effect of PEDF via its receptors as an antiangiogenic agent and as a direct anticancer agent. The majority of the PEDF patents describe the antiangiogenic ability and usage of recombinant vectors as the mode of treatment delivery. PEDF's therapeutic potential against different diseases and the discovery of its receptors open possibilities for improving PEDF-based peptide design and drug delivery modes.
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Affiliation(s)
- Katrina B Manalo
- Department of Orthopaedics, University of Melbourne, St. Vincent's Hospital, VIC, Australia
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14
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Subramanian P, Crawford SE, Becerra SP. Assays for the antiangiogenic and neurotrophic serpin pigment epithelium-derived factor. Methods Enzymol 2011; 499:183-204. [PMID: 21683255 DOI: 10.1016/b978-0-12-386471-0.00010-9] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/18/2022]
Abstract
Pigment epithelium-derived factor (PEDF) is a secreted serpin that exhibits a variety of interesting biological activities. The multifunctional PEDF has neurotrophic and antiangiogenic properties, and acts in retinal differentiation, survival, and maintenance. It is also antitumorigenic and antimetastatic, and has stem cell self-renewal properties. It is widely distributed in the human body and exists in abundance in the eye as a soluble extracellular glycoprotein. Its levels are altered in diseases characterized by retinopathies and angiogenesis. Its mechanisms of neuroprotection and angiogenesis are associated with receptor interactions at cell-surface interfaces and changes in protein expression. This serpin lacks demonstrable serine protease inhibitory activity, but has binding affinity to extracellular matrix components and cell-surface receptors. Here we describe purification protocols, methods to quantify PEDF, and determine interactions with specific molecules, as well as neurotrophic and angiogenesis assays for this multifunctional protein.
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Affiliation(s)
- Preeti Subramanian
- Section of Protein Structure and Function, National Eye Institute, NIH, Bethesda, Maryland, USA
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15
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Abstract
Pigment epithelium-derived factor (PEDF) is an endogenously produced glycoprotein with a spectrum of biological roles across diverse pathologies. Recent research has focused on the biochemical properties of PEDF and its associated receptors. This review discusses the recent developments in PEDF biochemistry and how this new knowledge will help progress our understanding of PEDF as a molecular mediator for anti-angiogenesis and -tumorigenesis. Additionally, pathophysiological roles for PEDF in healing and tissue homeostasis are being revealed and our enhanced understanding of the interactions between PEDF and its receptors may yet prove useful in propelling PEDF towards clinical application.
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Affiliation(s)
- Matthew L Broadhead
- Department of Orthopaedics, St Vincent's Hospital, University of Melbourne, Melbourne, Vic., Australia
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16
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Serotonin transporter clustering in blood lymphocytes of reeler mice. Cardiovasc Psychiatry Neurol 2010; 2010:396282. [PMID: 20414372 PMCID: PMC2858282 DOI: 10.1155/2010/396282] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/21/2009] [Accepted: 02/10/2010] [Indexed: 11/29/2022] Open
Abstract
Serotonin transporter clustering is an important feature for regulation of this transporter activity. We used immunocytochemistry to analyze alterations in serotonin transporter clustering in blood lymphocytes of reeler mice. Serotonin transporter immunolabelling is observed mostly as a patchy staining in lymphocytes membranes. Comparison of the number and size of serotonin transporter clusters in wild-type mice, heterozygous reeler mice, and homozygous reeler mice showed an increase in the number and size of clusters in heterozygous reeler mice, but only an increase in clusters size in homozygous reeler mice. Reelin is down-regulated in the brain of schizophrenia, autism, and mood disorders, and is also expressed in blood plasma. There is the possibility therefore that alterations in serotonin transporter clustering in blood lymphocytes associated with a decrease in reelin expression may be operative in some cardiovascular or immune system alterations showing comorbidity with these mental disorders.
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Bernard A, Gao-Li J, Franco CA, Bouceba T, Huet A, Li Z. Laminin receptor involvement in the anti-angiogenic activity of pigment epithelium-derived factor. J Biol Chem 2009; 284:10480-90. [PMID: 19224861 DOI: 10.1074/jbc.m809259200] [Citation(s) in RCA: 131] [Impact Index Per Article: 8.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/19/2022] Open
Abstract
Pigment epithelium-derived factor (PEDF) is a multifunctional protein with neurotrophic, anti-oxidative, and anti-inflammatory properties. It is also one of the most potent endogenous inhibitors of angiogenesis, playing an important role in restricting tumor growth, invasion, and metastasis. Studies show that PEDF binds to cell surface proteins, but little is known about how it exerts its effects. Recently, research identified phospholipase A(2)/nutrin/patatin-like phospholipase domain-containing 2 as one PEDF receptor. To identify other receptors, we performed yeast two-hybrid screening using PEDF as bait and discovered that the non-integrin 37/67-kDa laminin receptor (LR) is another PEDF receptor. Co-immunoprecipitation, His tag pulldown, and surface plasmon resonance assays confirmed the interaction between PEDF and LR. Using the yeast two-hybrid method, we further restricted the LR-interacting domain on PEDF to a 34-amino acid (aa) peptide (aa 44-77) and the PEDF-interacting domain on LR to a 91-aa fragment (aa 120-210). A 25-mer peptide named P46 (aa 46-70), derived from 34-mer, interacts with LR in surface plasmon resonance assays and binds to endothelial cell (EC) membranes. This peptide induces EC apoptosis and inhibits EC migration, tube-like network formation in vitro, and retinal angiogenesis ex vivo, like PEDF. Our results suggest that LR is a real PEDF receptor that mediates PEDF angiogenesis inhibition.
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Affiliation(s)
- Adrien Bernard
- Université Pierre et Marie Curie, Univerisité Paris 06, UR4, Aging, Stress and Inflammation and Institut Fédératif de Recherche 83, 75252 Paris, France
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Becerra SP, Perez-Mediavilla LA, Weldon JE, Locatelli-Hoops S, Senanayake P, Notari L, Notario V, Hollyfield JG. Pigment epithelium-derived factor binds to hyaluronan. Mapping of a hyaluronan binding site. J Biol Chem 2008; 283:33310-20. [PMID: 18805795 DOI: 10.1074/jbc.m801287200] [Citation(s) in RCA: 38] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
Pigment epithelium-derived factor (PEDF) is a multifunctional serpin with antitumorigenic, antimetastatic, and differentiating activities. PEDF is found within tissues rich in the glycosaminoglycan hyaluronan (HA), and its amino acid sequence contains putative HA-binding motifs. We show that PEDF coprecipitation with glycosaminoglycans in media conditioned by human retinoblastoma Y-79 cells decreased after pretreatments with hyaluronidase, implying an association between HA and PEDF. Direct binding of human recombinant PEDF to highly purified HA was demonstrated by coprecipitation in the presence of cetylpyridinium chloride. Binding of PEDF to HA was concentration-dependent and saturable. The PEDF-HA interactions were sensitive to increasing NaCl concentrations, indicating an ionic nature of these interactions and having affinity higher than PEDF-heparin. Competition assays showed that PEDF can bind heparin and HA simultaneously. PEDF chemically modified with fluorescein retained the capacity for interacting with HA but lacked heparin affinity, suggesting one or more distinct HA-binding regions on PEDF. The HA-binding region was examined by site-directed mutagenesis. Single-point and cumulative alterations at basic residues within the putative HA-binding motif K189A/K191A/R194A/K197A drastically reduced the HA-binding activity without affecting heparin- or collagen I binding of PEDF. Cumulative alterations at sites critical for heparin binding (K146A/K147A/R149A) decreased HA affinity but not collagen I binding. Thus these clusters of basic residues (BXBXXBXXB and BX3AB2XB motifs) in PEDF are functional regions for binding HA. In the spatial PEDF structure they are located in distinct areas away from the collagen-binding site. The HA-binding activity of PEDF may contribute to deposition in the extracellular matrix and to its reported antitumor/antimetastatic effects.
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Demetriades AM, Deering T, Liu H, Lu L, Gehlbach P, Packer JD, Gabhann FM, Popel AS, Wei LL, Campochiaro PA. Trans-scleral Delivery of Antiangiogenic Proteins. J Ocul Pharmacol Ther 2008; 24:70-9. [DOI: 10.1089/jop.2007.0061] [Citation(s) in RCA: 25] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022] Open
Affiliation(s)
- Anna M. Demetriades
- Department of Ophthalmology, The Johns Hopkins University, School of Medicine, Baltimore, MD
| | - Tye Deering
- Department of Ophthalmology, The Johns Hopkins University, School of Medicine, Baltimore, MD
| | - Hansheng Liu
- Department of Ophthalmology, The Johns Hopkins University, School of Medicine, Baltimore, MD
| | - Lili Lu
- Department of Ophthalmology, The Johns Hopkins University, School of Medicine, Baltimore, MD
| | - Peter Gehlbach
- Department of Ophthalmology, The Johns Hopkins University, School of Medicine, Baltimore, MD
| | - Jonathan D. Packer
- Department of Ophthalmology, The Johns Hopkins University, School of Medicine, Baltimore, MD
| | - Feilim Mac Gabhann
- Department of Biomedical Engineering, The Johns Hopkins University, School of Medicine, Baltimore, MD
| | - Aleksander S. Popel
- Department of Biomedical Engineering, The Johns Hopkins University, School of Medicine, Baltimore, MD
| | | | - Peter A. Campochiaro
- Department of Ophthalmology, The Johns Hopkins University, School of Medicine, Baltimore, MD
- Department of Neuroscience, The Johns Hopkins University, School of Medicine, Baltimore, MD
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Lee CY, Illarionov B, Woo YE, Kemter K, Kim RR, Eberhardt S, Cushman M, Eisenreich W, Fischer M, Bacher A. Ligand binding properties of the N-terminal domain of riboflavin synthase from Escherichia coli. BMB Rep 2007; 40:239-46. [PMID: 17394775 DOI: 10.5483/bmbrep.2007.40.2.239] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Riboflavin synthase from Escherichia coli is a homotrimer of 23.4 kDa subunits and catalyzes the formation of one molecule each of riboflavin and 5-amino-6-ribitylamino- 2,4(1H,3H)-pyrimidinedione by the transfer of a 4-carbon moiety between two molecules of the substrate, 6,7- dimethyl-8-ribityllumazine. Each subunit comprises two closely similar folding domains. Recombinant expression of the N-terminal domain is known to provide a c(2)-symmetric homodimer. In this study, the binding properties of wild type as well as two mutated proteins of N-terminal domain of riboflavin synthase with various ligands were tested. The replacement of the amino acid residue A43, located in the second shell of riboflavin synthase active center, in the recombinant N-terminal domain dimer reduces the affinity for 6,7-dimethyl-8-ribityllumazine. The mutation of the amino acid residue C48 forming part of activity cavity of the enzyme causes significant (19)F NMR chemical shift modulation of trifluoromethyl derivatives of 6,7-dimethyl-8-ribityllumazine in complex with the protein, while substitution of A43 results in smaller chemical shift changes.
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Affiliation(s)
- Chan Yong Lee
- Lehrstuhl fur Organische Chemie und Biochemie, Technische Universitat Munchen, D-85747 Garching, Germany.
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Valnickova Z, Petersen SV, Nielsen SB, Otzen DE, Enghild JJ. Heparin Binding Induces a Conformational Change in Pigment Epithelium-derived Factor. J Biol Chem 2007; 282:6661-7. [PMID: 17202143 DOI: 10.1074/jbc.m610471200] [Citation(s) in RCA: 16] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
Pigment epithelium-derived factor (PEDF) is a noninhibitory serpin found in plasma and in the extracellular space. The protein is involved in different biological processes including cell differentiation and survival. In addition, it is a potent inhibitor of angiogenesis. The function is likely associated with binding to cell surface receptors in a heparin-dependent way (Alberdi, E. M., Weldon, J. E., and Becerra, S. P. (2003) BMC Biochem. 4, 1). We have investigated the structural basis for this observation and show that heparin induces a conformational change in the vicinity of Lys(178). This structural change was evident both when binding to intact heparin and specific heparin-derived oligosaccharides at physiological conditions or simply when exposing PEDF to low ionic strength. Binding to other glycosaminoglycans, heparin-derived oligosaccharides smaller than hexadecasaccharides (dp16), or type I collagen did not affect the structure of PEDF. The conformational change is likely to expose the epitope involved in binding to the receptor and thus regulates the interactions with cell surface receptors.
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Affiliation(s)
- Zuzana Valnickova
- Center for Insoluble Protein Structures (inSPIN), Department of Molecular Biology, University of Aarhus, DK-8000 Aarhus, Denmark
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Conti A, Ricchiuto P, Iannaccone S, Sferrazza B, Cattaneo A, Bachi A, Reggiani A, Beltramo M, Alessio M. Pigment epithelium-derived factor is differentially expressed in peripheral neuropathies. Proteomics 2005; 5:4558-67. [PMID: 16196102 DOI: 10.1002/pmic.200402088] [Citation(s) in RCA: 31] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/10/2023]
Abstract
Peripheral neuropathies are characterized by asymmetrical slowly progressive weakness with no upper motor neuron signs, and can occur either with or without pain. Due to poor knowledge of the disease mechanisms, available pain treatment is very limited. Because of the difficulties and invasiveness involved when performing direct analysis on peripheral and CNS, pathological markers can be searched for in the cerebrospinal fluid (CSF) as an alternative. To investigate pain mechanisms in peripheral neuropathy and find diagnostic markers, CSF samples were analyzed by a differential expression proteomic approach. We studied CSF from: neuropathic patients with pain (PN), without pain (NPN) and healthy controls (CN). 2-DE analysis showed ten protein spots differentially expressed, and six of these were identified by MS. In NPN patients we found an expression level decrease of three pigment epithelium-derived factor (PEDF) protein isoforms. Immunoblot with a specific antibody revealed the presence of additional PEDF isoforms not highlighted by differential expression analysis. Fucose residues on the oligosaccharide chain were found only in the isoforms down regulated in NPN patients. Considered as PEDF has important neurobiological effects, it might be considered an interesting pathology marker.
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Affiliation(s)
- Antonio Conti
- Proteome Biochemistry, San Raffaele Scientific Institute, Milan, Italy
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23
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Ren JG, Jie C, Talbot C. How PEDF prevents angiogenesis: a hypothesized pathway. Med Hypotheses 2005; 64:74-8. [PMID: 15533615 DOI: 10.1016/j.mehy.2004.05.016] [Citation(s) in RCA: 27] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/12/2004] [Accepted: 05/18/2004] [Indexed: 01/13/2023]
Abstract
Pigment epithelium-derived factor (PEDF) is a multiple functional protein, coded by the serine proteinase inhibitor, clade F, member 1 (SERPINF1) gene, which has both anti-angiogenic activity and neurotrophic activity at the same time. Its antiangiogenic activity in the mammalian eye is the most potent known at this time. However, the mechanism(s) by which PEDF works in vivo is still uncertain. Some observations suggest that PEDF can simultaneously inhibit the migration and proliferation induced by vascular endothelial growth factor (VEGF), and then further inhibits angiogenesis by interacting with specific cell surface receptors, but no such receptor has been reported to date. Here we propose a hypothesis that PEDF exerts its function by binding with intergrins. Intergrin can therefore serve as the receptor of PEDF.
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Affiliation(s)
- Jian-Guo Ren
- Department of Pathology, Brighman and Women's Hospital and Harvard Medical School, Thorn 530, 75 Francis Street, Boston, MA 02115, USA.
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Francis MK, Appel S, Meyer C, Balin SJ, Balin AK, Cristofalo VJ. Loss of EPC-1/PEDF expression during skin aging in vivo. J Invest Dermatol 2004; 122:1096-105. [PMID: 15140209 DOI: 10.1111/j.0022-202x.2004.22510.x] [Citation(s) in RCA: 33] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/03/2023]
Abstract
EPC-1/PEDF (early population doubling level cDNA-1/retinal pigmented epithelium-derived factor) is a single-copy, quiescence-specific gene that is transcribed into a 1.5 kb mRNA and then translated into a 50 kDa secreted protein that is a potent inhibitor of angiogenesis. EPC-1 expression has been detected in a number of cultured cell lines, including lung and skin fibroblasts, retinal pigmented epithelial cells, and endometrial stromal fibroblasts. Furthermore, its expression has been shown to decline during replicative aging of these cells in culture. In this report, we describe our examination of the age-related changes in EPC-1 expression in situ in skin sections from donors of different ages. EPC-1 mRNA is detected primarily in the dermal layer of the skin and its expression declines with increasing donor age. This decline is statistically significant between young (less than 31 years old) and middle-aged (between 30 and 60 years old) donors, with the decline becoming less dramatic at older ages. This age-related decline in the expression of an angiogenic inhibitor contributes to the imbalance of angiogenic modulators that is observed during aging. In fact, this decline may reflect a compensatory change to help reverse the decline of angiogenesis marked by reduced abundance of microvessels. This downregulation of an angiogenesis inhibitor may, in turn, play a critical role in the development of diseases caused by abnormal vascularization. The potential role of the age-associated decline in EPC-1 expression in tissue remodeling and in the development of skin diseases with excessive angiogenesis may provide new insights into disease prevention.
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Affiliation(s)
- Mary Kay Francis
- Lankenau Institute for Medical Research, Wynnewood, Pennsylvania, USA.
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Ibarra CA, Blouse GE, Christian TD, Shore JD. The contribution of the exosite residues of plasminogen activator inhibitor-1 to proteinase inhibition. J Biol Chem 2003; 279:3643-50. [PMID: 14594804 DOI: 10.1074/jbc.m310601200] [Citation(s) in RCA: 32] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
The binding of plasminogen activator inhibitor-1 (PAI-1) to serine proteinases, such as tissue-type plasminogen activator (tPA) and urokinase-type plasminogen activator (uPA), is mediated by the exosite interactions between the surface-exposed variable region-1, or 37-loop, of the proteinase and the distal reactive center loop (RCL) of PAI-1. Although the contribution of such interactions to the inhibitory activity of PAI-1 has been established, the specific mechanistic steps affected by interactions at the distal RCL remain unknown. We have used protein engineering, stopped-flow fluorimetry, and rapid acid quenching techniques to elucidate the role of exosite interactions in the neutralization of tPA, uPA, and beta-trypsin by PAI-1. Alanine substitutions at the distal P4' (Glu-350) and P5' (Glu-351) residues of PAI-1 reduced the rates of Michaelis complex formation (k(a)) and overall inhibition (k(app)) with tPA by 13.4- and 4.7-fold, respectively, whereas the rate of loop insertion or final acyl-enzyme formation (k(lim)) increased by 3.3-fold. The effects of double mutations on k(a), k(lim), and k(app) were small with uPA and nonexistent with beta-trypsin. We provide the first kinetic evidence that the removal of exosite interactions significantly alters the formation of the noncovalent Michaelis complex, facilitating the release of the primed side of the distal loop from the active-site pocket of tPA and the subsequent insertion of the cleaved reactive center loop into beta-sheet A. Moreover, mutational analysis indicates that the P5' residue contributes more to the mechanism of tPA inhibition, notably by promoting the formation of a final Michaelis complex.
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Affiliation(s)
- Catherine A Ibarra
- Division of Biochemical, Research, Department of Pathology, Henry Ford Health Sciences Center, Detroit, Michigan 48202, USA
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Kim SY, Mocanu C, Mcleod DS, Bhutto IA, Merges C, Eid M, Tong P, Lutty GA. Expression of pigment epithelium-derived factor (PEDF) and vascular endothelial growth factor (VEGF) in sickle cell retina and choroid. Exp Eye Res 2003; 77:433-45. [PMID: 12957143 DOI: 10.1016/s0014-4835(03)00174-x] [Citation(s) in RCA: 48] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
Pigment epithelium-derived factor (PEDF) has been shown to be an inhibitor of angiogenesis as well as a multipotent neurotrophic factor in the mammalian eye. Changes in PEDF levels have been correlated with development of retinal neovascularization in oxygen-induced retinopathy. The purpose of this study was to determine the localization and relative level of PEDF in human retinas and choroids using immunohistochemistry and evaluate the changes in PEDF and vascular endothelial growth factor (VEGF) localization and their relation to the progression of proliferative sickle cell retinopathy. Cryopreserved tissues from eyes of normal subjects and subjects with non-proliferative or proliferative sickle cell retinopathy were used with streptavidin peroxidase immunohistochemistry. A rabbit polyclonal antibody was made against recombinant human PEDF. Binding of the antibody was blocked by preincubation of the antibody with excess human recombinant PEDF. Relative levels of immunoreactivity were scored with a seven-point grading system and by microdensitometric analysis.The most prominent sites of PEDF localization in the normal eye were the vitreous condensed at the internal limiting membrane and RPE-Bruch's membrane-choriocapillaris complex. PEDF was also prominent in choroidal stroma. There was limited immunoreactivity in some cells of the neural retinas, in blood vessels and in the interphotoreceptor matrix (IPM). There was no difference in ratio (1.47 vs. 1.44) of PEDF/VEGF or the relative levels of either growth factor in the retinal vasculatures of the control subjects and perfused area of non-proliferative sickle cell retinas. The ratio was increased in the non-perfused area of the non-proliferative sickle cell retinas (2.24). In eyes with proliferative sickle cell retinopathy, elevated PEDF and VEGF immunostaining was present in viable vessels of sea fan neovascular formations as well as feeder vessels of sea fans. The PEDF/VEGF ratio in sea fans was 1.0. Immunoreactivity for PEDF was prominent in retinal vessels in non-perfused regions and in atrophic sea fans, while VEGF immunoreactivity was weak or absent in these structures. In conclusion, PEDF and VEGF were both significantly elevated in viable sea fan formations in sickle cell disease (p<0.05) but only PEDF was present in non-viable sea fans. The highest levels of PEDF in all eyes were associated with extracellular matrices (vitreous, choroidal stroma, IPM, and walls of blood vessels). PEDF might play an important role in inhibiting angiogenesis and inducing the regression of sea fans. Progression of angiogenesis may be dependent on the ratio of PEDF/VEGF.
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Affiliation(s)
- Sahng Yeon Kim
- The Wilmer Ophthalmological Institute, Department of Ophthalmology, School of Medicine, The Johns Hopkins University, Baltimore, MD 21287-9115, USA
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