1
|
Conover CA, Oxvig C. The Pregnancy-Associated Plasma Protein-A (PAPP-A) Story. Endocr Rev 2023; 44:1012-1028. [PMID: 37267421 DOI: 10.1210/endrev/bnad017] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/10/2023] [Revised: 05/01/2023] [Accepted: 05/31/2023] [Indexed: 06/04/2023]
Abstract
Pregnancy-associated plasma protein-A (PAPP-A) was first identified in the early 1970s as a placental protein of unknown function, present at high concentrations in the circulation of pregnant women. In the mid-to-late 1990s, PAPP-A was discovered to be a metzincin metalloproteinase, expressed by many nonplacental cells, that regulates local insulin-like growth factor (IGF) activity through cleavage of high-affinity IGF binding proteins (IGFBPs), in particular IGFBP-4. With PAPP-A as a cell surface-associated enzyme, the reduced affinity of the cleavage fragments results in increased IGF available to bind and activate IGF receptors in the pericellular environment. This proteolytic regulation of IGF activity is important, since the IGFs promote proliferation, differentiation, migration, and survival in various normal and cancer cells. Thus, there has been a steady growth in investigation of PAPP-A structure and function outside of pregnancy. This review provides historical perspective on the discovery of PAPP-A and its structure and cellular function, highlights key studies of the first 50 years in PAPP-A research, and introduces new findings from recent years.
Collapse
Affiliation(s)
- Cheryl A Conover
- Division of Endocrinology, Mayo Clinic, Rochester, MN 55905, USA
| | - Claus Oxvig
- Department of Molecular Biology and Genetics, Aarhus University, 8000 Aarhus, Denmark
| |
Collapse
|
2
|
Oxvig C, Conover CA. The Stanniocalcin-PAPP-A-IGFBP-IGF Axis. J Clin Endocrinol Metab 2023; 108:1624-1633. [PMID: 36718521 DOI: 10.1210/clinem/dgad053] [Citation(s) in RCA: 9] [Impact Index Per Article: 9.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/03/2022] [Revised: 01/20/2023] [Accepted: 01/25/2023] [Indexed: 02/01/2023]
Abstract
The pappalysin metalloproteinases, PAPP-A and PAPP-A2, have emerged as highly specific proteolytic enzymes involved in the regulation of insulin-like growth factor (IGF) signaling. The only known pappalysin substrates are a subset of the IGF binding proteins (IGFBPs), which bind IGF-I or IGF-II with high affinity to antagonize receptor binding. Thus, by cleaving IGFBPs, the pappalysins have the potential to increase IGF bioactivity and hence promote IGF signaling. This is relevant both in systemic and local IGF regulation, in normal and several pathophysiological conditions. Stanniocalcin-1 and -2 were recently found to be potent pappalysin inhibitors, thus comprising the missing components of a complete proteolytic system, the stanniocalcin-PAPP-A-IGFBP-IGF axis. Here, we provide the biological context necessary for understanding the properties of this molecular network, and we review biochemical data, animal experiments, clinical data, and genetic data supporting the physiological operation of this branch as an important part of the IGF system. However, although in vivo data clearly illustrate its power, it is a challenge to understand its subtle operation, for example, multiple equilibria and inhibitory kinetics may determine how, where, and when the IGF receptor is stimulated. In addition, literally all of the regulatory proteins have suspected or known activities that are not directly related to IGF signaling. How such activities may integrate with IGF signaling is also important to address in the future.
Collapse
Affiliation(s)
- Claus Oxvig
- Department of Molecular Biology and Genetics, Aarhus University, DK-8000 C, Aarhus, Denmark
| | - Cheryl A Conover
- Division of Endocrinology, Mayo Clinic, Rochester, MN 55905, USA
| |
Collapse
|
3
|
Conover CA, Bale LK. Senescence induces proteolytically-active PAPP-A secretion and association with extracellular vesicles in human pre-adipocytes. Exp Gerontol 2023; 172:112070. [PMID: 36549546 PMCID: PMC9868105 DOI: 10.1016/j.exger.2022.112070] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/26/2022] [Revised: 12/16/2022] [Accepted: 12/17/2022] [Indexed: 12/24/2022]
Abstract
Senescence is a cellular response to various stressors characterized by irreversible cell cycle arrest, resistance to apoptosis and expression of a senescence-associated secretory phenotype (SASP). Interestingly, studies where senescent cells were deleted in mice produced beneficial effects similar to those where the zinc metalloproteinase, PAPP-A, was deleted in mice. In this study, we investigated the effect of senescence on PAPP-A secretion and activity in primary cultures of adult human pre-adipocytes. Cultured pre-adipocytes were isolated from subcutaneous (Sub) and omental (Om) fat. Senescence was induced with low dose etoposide. PAPP-A protein was measured by an ultrasensitive PAPP-A ELISA. PAPP-A proteolytic activity was measured by a specific substrate cleavage assay. Senescence significantly increased PAPP-A levels in both Sub and Om conditioned medium (CM) 8- to 15-fold over non-senescent CM. Proteolytic activity reflected PAPP-A protein with 12- to 18-fold greater activity in senescent CM versus non-senescent CM. Furthermore, PAPP-A was found at high levels on the surface of extracellular vesicles secreted by senescent pre-adipocytes and was proteolytically active. In conclusion, we identified enzymatically active PAPP-A as a component of human pre-adipocyte SASP. This recognition warrants further investigation of PAPP-A as a new biomarker for senescence and a potential therapeutic target to control of the spread of senescence in adipose tissue.
Collapse
Affiliation(s)
- Cheryl A Conover
- Division of Endocrinology, Metabolism and Nutrition, Endocrine Research Unit, Mayo Clinic, Rochester, MN, USA.
| | - Laurie K Bale
- Division of Endocrinology, Metabolism and Nutrition, Endocrine Research Unit, Mayo Clinic, Rochester, MN, USA
| |
Collapse
|
4
|
Zhong Q, Chu H, Wang G, Zhang C, Li R, Guo F, Meng X, Lei X, Zhou Y, Ren R, Tao L, Li N, Gao N, Wei Y, Qiao J, Hang J. Structural insights into the covalent regulation of PAPP-A activity by proMBP and STC2. Cell Discov 2022; 8:137. [PMID: 36550107 PMCID: PMC9780223 DOI: 10.1038/s41421-022-00502-2] [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: 10/23/2022] [Accepted: 11/25/2022] [Indexed: 12/24/2022] Open
Abstract
Originally discovered in the circulation of pregnant women as a protein secreted by placental trophoblasts, the metalloprotease pregnancy-associated plasma protein A (PAPP-A) is also widely expressed by many other tissues. It cleaves insulin-like growth factor-binding proteins (IGFBPs) to increase the bioavailability of IGFs and plays essential roles in multiple growth-promoting processes. While the vast majority of the circulatory PAPP-A in pregnancy is proteolytically inactive due to covalent inhibition by proform of eosinophil major basic protein (proMBP), the activity of PAPP-A can also be covalently inhibited by another less characterized modulator, stanniocalcin-2 (STC2). However, the structural basis of PAPP-A proteolysis and the mechanistic differences between these two modulators are poorly understood. Here we present two cryo-EM structures of endogenous purified PAPP-A in complex with either proMBP or STC2. Both modulators form 2:2 heterotetramer with PAPP-A and establish extensive interactions with multiple domains of PAPP-A that are distal to the catalytic cleft. This exosite-binding property results in a steric hindrance to prevent the binding and cleavage of IGFBPs, while the IGFBP linker region-derived peptides harboring the cleavage sites are no longer sensitive to the modulator treatment. Functional investigation into proMBP-mediated PAPP-A regulation in selective intrauterine growth restriction (sIUGR) pregnancy elucidates that PAPP-A and proMBP collaboratively regulate extravillous trophoblast invasion and the consequent fetal growth. Collectively, our work reveals a novel covalent exosite-competitive inhibition mechanism of PAPP-A and its regulatory effect on placental function.
Collapse
Affiliation(s)
- Qihang Zhong
- grid.411642.40000 0004 0605 3760Center for Reproductive Medicine, Department of Obstetrics and Gynecology, Peking University Third Hospital, Beijing, China ,grid.419897.a0000 0004 0369 313XKey Laboratory of Assisted Reproduction, Ministry of Education, Beijing, China ,Beijing Key Laboratory of Reproductive Endocrinology and Assisted Reproduction, Beijing, China ,grid.411642.40000 0004 0605 3760National Clinical Research Center for Obstetrics and Gynecology, Beijing, China
| | - Honglei Chu
- grid.411642.40000 0004 0605 3760Center for Reproductive Medicine, Department of Obstetrics and Gynecology, Peking University Third Hospital, Beijing, China ,grid.419897.a0000 0004 0369 313XKey Laboratory of Assisted Reproduction, Ministry of Education, Beijing, China ,Beijing Key Laboratory of Reproductive Endocrinology and Assisted Reproduction, Beijing, China ,grid.411642.40000 0004 0605 3760National Clinical Research Center for Obstetrics and Gynecology, Beijing, China
| | - Guopeng Wang
- grid.11135.370000 0001 2256 9319State Key Laboratory of Membrane Biology, School of Life Sciences, Peking University, Beijing, China
| | - Cheng Zhang
- grid.412474.00000 0001 0027 0586Department of Gastrointestinal Oncology, Key Laboratory of Carcinogenesis and Translational Research (Ministry of Education/Beijing), Peking University Cancer Hospital & Institute, Beijing, China
| | - Rong Li
- grid.411642.40000 0004 0605 3760Center for Reproductive Medicine, Department of Obstetrics and Gynecology, Peking University Third Hospital, Beijing, China ,grid.419897.a0000 0004 0369 313XKey Laboratory of Assisted Reproduction, Ministry of Education, Beijing, China ,Beijing Key Laboratory of Reproductive Endocrinology and Assisted Reproduction, Beijing, China ,grid.411642.40000 0004 0605 3760National Clinical Research Center for Obstetrics and Gynecology, Beijing, China
| | - Fusheng Guo
- grid.11135.370000 0001 2256 9319Beijing National Laboratory for Molecular Sciences, State Key Laboratory of Natural and Biomimetic Drugs, Key Laboratory of Bioorganic Chemistry and Molecular Engineering of Ministry of Education, Department of Chemical Biology, College of Chemistry and Molecular Engineering, Synthetic and Functional Biomolecules Center, Peking University, Beijing, China ,grid.11135.370000 0001 2256 9319Peking-Tsinghua Center for Life Sciences, Peking University, Beijing, China
| | - Xinlu Meng
- grid.411642.40000 0004 0605 3760Center for Reproductive Medicine, Department of Obstetrics and Gynecology, Peking University Third Hospital, Beijing, China
| | - Xiaoguang Lei
- grid.11135.370000 0001 2256 9319Beijing National Laboratory for Molecular Sciences, State Key Laboratory of Natural and Biomimetic Drugs, Key Laboratory of Bioorganic Chemistry and Molecular Engineering of Ministry of Education, Department of Chemical Biology, College of Chemistry and Molecular Engineering, Synthetic and Functional Biomolecules Center, Peking University, Beijing, China ,grid.11135.370000 0001 2256 9319Peking-Tsinghua Center for Life Sciences, Peking University, Beijing, China ,grid.510951.90000 0004 7775 6738Institute for Cancer Research, Shenzhen Bay Laboratory, Shenzhen, Guangdong China
| | - Youli Zhou
- grid.10784.3a0000 0004 1937 0482School of Life and Health Sciences, The Chinese University of Hong Kong, Shenzhen, Guangdong China
| | - Ruobing Ren
- grid.10784.3a0000 0004 1937 0482School of Life and Health Sciences, The Chinese University of Hong Kong, Shenzhen, Guangdong China ,grid.8547.e0000 0001 0125 2443Shanghai Key Laboratory of Metabolic Remodeling and Health, Institute of Metabolism and Integrative Biology, Fudan University, Shanghai, China
| | - Lin Tao
- grid.412636.40000 0004 1757 9485Department of Orthopedics, First Hospital of China Medical University, Shenyang, Liaoning China
| | - Ningning Li
- grid.11135.370000 0001 2256 9319State Key Laboratory of Membrane Biology, School of Life Sciences, Peking University, Beijing, China
| | - Ning Gao
- grid.11135.370000 0001 2256 9319State Key Laboratory of Membrane Biology, School of Life Sciences, Peking University, Beijing, China ,grid.11135.370000 0001 2256 9319Peking-Tsinghua Center for Life Sciences, Peking University, Beijing, China
| | - Yuan Wei
- grid.411642.40000 0004 0605 3760Center for Reproductive Medicine, Department of Obstetrics and Gynecology, Peking University Third Hospital, Beijing, China ,grid.419897.a0000 0004 0369 313XKey Laboratory of Assisted Reproduction, Ministry of Education, Beijing, China ,Beijing Key Laboratory of Reproductive Endocrinology and Assisted Reproduction, Beijing, China ,grid.411642.40000 0004 0605 3760National Clinical Research Center for Obstetrics and Gynecology, Beijing, China
| | - Jie Qiao
- grid.411642.40000 0004 0605 3760Center for Reproductive Medicine, Department of Obstetrics and Gynecology, Peking University Third Hospital, Beijing, China ,grid.419897.a0000 0004 0369 313XKey Laboratory of Assisted Reproduction, Ministry of Education, Beijing, China ,Beijing Key Laboratory of Reproductive Endocrinology and Assisted Reproduction, Beijing, China ,grid.411642.40000 0004 0605 3760National Clinical Research Center for Obstetrics and Gynecology, Beijing, China ,grid.11135.370000 0001 2256 9319Peking-Tsinghua Center for Life Sciences, Peking University, Beijing, China
| | - Jing Hang
- grid.411642.40000 0004 0605 3760Center for Reproductive Medicine, Department of Obstetrics and Gynecology, Peking University Third Hospital, Beijing, China ,grid.419897.a0000 0004 0369 313XKey Laboratory of Assisted Reproduction, Ministry of Education, Beijing, China ,Beijing Key Laboratory of Reproductive Endocrinology and Assisted Reproduction, Beijing, China ,grid.411642.40000 0004 0605 3760National Clinical Research Center for Obstetrics and Gynecology, Beijing, China
| |
Collapse
|
5
|
Structure of the proteolytic enzyme PAPP-A with the endogenous inhibitor stanniocalcin-2 reveals its inhibitory mechanism. Nat Commun 2022; 13:6084. [PMID: 36257932 PMCID: PMC9579167 DOI: 10.1038/s41467-022-33698-8] [Citation(s) in RCA: 10] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/23/2022] [Accepted: 09/27/2022] [Indexed: 12/24/2022] Open
Abstract
The metzincin metalloproteinase PAPP-A plays a key role in the regulation of insulin-like growth factor (IGF) signaling by specific cleavage of inhibitory IGF binding proteins (IGFBPs). Using single-particle cryo-electron microscopy (cryo-EM), we here report the structure of PAPP-A in complex with its endogenous inhibitor, stanniocalcin-2 (STC2), neither of which have been reported before. The highest resolution (3.1 Å) was obtained for the STC2 subunit and the N-terminal approximately 1000 residues of the PAPP-A subunit. The 500 kDa 2:2 PAPP-A·STC2 complex is a flexible multidomain ensemble with numerous interdomain contacts. In particular, a specific disulfide bond between the subunits of STC2 and PAPP-A prevents dissociation, and interactions between STC2 and a module located in the very C-terminal end of the PAPP-A subunit prevent binding of its main substrate, IGFBP-4. While devoid of activity towards IGFBP-4, the active site cleft of the catalytic domain is accessible in the inhibited PAPP-A·STC2 complex, as shown by its ability to hydrolyze a synthetic peptide derived from IGFBP-4. Relevant to multiple human pathologies, this unusual mechanism of proteolytic inhibition may support the development of specific pharmaceutical agents, by which IGF signaling can be indirectly modulated.
Collapse
|
6
|
Jepsen MR, Østergaard JA, Conover CA, Wogensen L, Birn H, Krag SP, Fenton RA, Oxvig C. Increased activity of the metalloproteinase PAPP-A promotes diabetes-induced glomerular hypertrophy. Metabolism 2022; 132:155218. [PMID: 35588861 DOI: 10.1016/j.metabol.2022.155218] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/14/2021] [Revised: 04/19/2022] [Accepted: 05/12/2022] [Indexed: 12/27/2022]
Abstract
BACKGROUND Diabetic nephropathy (DN) is a serious complication of diabetes and a common cause of end stage renal failure. Insulin-like growth factor (IGF)-signaling has been implicated in DN, but is mechanistically poorly understood. Here, we assessed the activity of the metalloproteinase PAPP-A, an activator of IGF activity, and its possible interaction with the endogenous PAPP-A inhibitors stanniocalcin (STC)-1 and -2 in the mammalian kidney under normal and hyperglycemic conditions. METHODS AND RESULTS Immunohistochemistry demonstrated that PAPP-A, its proteolytic substrate IGF binding protein-4, STC1 and STC2 are present in the human kidney. Endogenous inhibited complexes of PAPP-A (PAPP-A:STC1 and PAPP-A:STC2) were demonstrated in media conditioned by human mesangial cells (HMCs), suggesting that PAPP-A activity is regulated by the STCs in kidney tissue. A method for the selective detection of active PAPP-A in tissue was developed and a significant increase in glomerular active PAPP-A in human diabetic kidney relative to normal was observed. In DN patients, the estimated glomerular filtration rate correlated with PAPP-A activity. In diabetic mice, glomerular growth was reduced when PAPP-A activity was antagonized by adeno-associated virus-mediated overexpression of STC2. CONCLUSION We propose that PAPP-A activity in renal tissue is precisely balanced by STC1 and STC2. An imbalance in this equilibrium causing increased PAPP-A enzymatic activity potentially contributes to the development of DN, and thus, therapeutic targeting of PAPP-A activity may represent a novel strategy for its treatment.
Collapse
Affiliation(s)
- Malene R Jepsen
- Department of Molecular Biology and Genetics, Aarhus University, DK-8000 Aarhus C, Denmark
| | - Jakob A Østergaard
- Department of Endocrinology and Internal Medicine, Aarhus University Hospital and Department of Clinical Medicine, Aarhus University, DK-8200 Aarhus N, Denmark; Steno Diabetes Center Aarhus, Aarhus University Hospital, DK-8200 Aarhus N, Denmark
| | | | - Lise Wogensen
- Dean's Office, Faculty of Health, Aarhus University, DK-8000 Aarhus C, Denmark
| | - Henrik Birn
- Department of Renal Medicine, Aarhus University Hospital, DK-8200 Aarhus N, Denmark; Department of Biomedicine, Aarhus University, DK-8000 Aarhus C, Denmark
| | - Søren P Krag
- Department of Histopathology, Aarhus University Hospital, DK-8200 Aarhus N, Denmark
| | - Robert A Fenton
- Department of Biomedicine, Aarhus University, DK-8000 Aarhus C, Denmark
| | - Claus Oxvig
- Department of Molecular Biology and Genetics, Aarhus University, DK-8000 Aarhus C, Denmark.
| |
Collapse
|
7
|
Man L, Lustgarten Guahmich N, Kallinos E, Caiazza B, Khan M, Liu ZY, Patel R, Torres C, Pepin D, Yang HS, Bodine R, Zaninovic N, Schattman G, Rosenwaks Z, James D. Chronic superphysiologic AMH promotes premature luteinization of antral follicles in human ovarian xenografts. SCIENCE ADVANCES 2022; 8:eabi7315. [PMID: 35263130 PMCID: PMC8906729 DOI: 10.1126/sciadv.abi7315] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/26/2021] [Accepted: 01/14/2022] [Indexed: 05/19/2023]
Abstract
Anti-Müllerian hormone (AMH) is produced by growing ovarian follicles and provides a diagnostic measure of reproductive reserve in women; however, the impact of AMH on folliculogenesis is poorly understood. We cotransplanted human ovarian cortex with control or AMH-expressing endothelial cells in immunocompromised mice and recovered antral follicles for purification and downstream single-cell RNA sequencing of granulosa and theca/stroma cell fractions. A total of 38 antral follicles were observed (19 control and 19 AMH) at long-term intervals (>10 weeks). In the context of exogenous AMH, follicles exhibited a decreased ratio of primordial to growing follicles and antral follicles of increased diameter. Transcriptomic analysis and immunolabeling revealed a marked increase in factors typically noted at more advanced stages of follicle maturation, with granulosa and theca/stroma cells also displaying molecular hallmarks of luteinization. These results suggest that superphysiologic AMH alone may contribute to ovulatory dysfunction by accelerating maturation and/or luteinization of antral-stage follicles.
Collapse
Affiliation(s)
- Limor Man
- Ronald O. Perelman and Claudia Cohen Center for Reproductive Medicine and Infertility, Weill Cornell Medicine, New York, NY 10065, USA
| | - Nicole Lustgarten Guahmich
- Ronald O. Perelman and Claudia Cohen Center for Reproductive Medicine and Infertility, Weill Cornell Medicine, New York, NY 10065, USA
| | - Eleni Kallinos
- Ronald O. Perelman and Claudia Cohen Center for Reproductive Medicine and Infertility, Weill Cornell Medicine, New York, NY 10065, USA
| | - Barbara Caiazza
- Ronald O. Perelman and Claudia Cohen Center for Reproductive Medicine and Infertility, Weill Cornell Medicine, New York, NY 10065, USA
| | - Monica Khan
- Ronald O. Perelman and Claudia Cohen Center for Reproductive Medicine and Infertility, Weill Cornell Medicine, New York, NY 10065, USA
| | - Zong-Ying Liu
- Ronald O. Perelman and Claudia Cohen Center for Reproductive Medicine and Infertility, Weill Cornell Medicine, New York, NY 10065, USA
| | - Ritaben Patel
- Ronald O. Perelman and Claudia Cohen Center for Reproductive Medicine and Infertility, Weill Cornell Medicine, New York, NY 10065, USA
| | - Carmen Torres
- Ronald O. Perelman and Claudia Cohen Center for Reproductive Medicine and Infertility, Weill Cornell Medicine, New York, NY 10065, USA
| | - David Pepin
- Department of Surgery, Harvard Medical School, Boston, MA 02215, USA
- Pediatric Surgical Research Laboratories, Massachusetts General Hospital, Boston, MA 02214, USA
| | - He S. Yang
- Department of Pathology and Laboratory Medicine, Weill Cornell Medicine, New York, NY 10065, USA
| | - Richard Bodine
- Ronald O. Perelman and Claudia Cohen Center for Reproductive Medicine and Infertility, Weill Cornell Medicine, New York, NY 10065, USA
| | - Nikica Zaninovic
- Ronald O. Perelman and Claudia Cohen Center for Reproductive Medicine and Infertility, Weill Cornell Medicine, New York, NY 10065, USA
- Tri-Institutional Stem Cell Derivation Laboratory, Weill Cornell Medicine, New York, NY 10065, USA
| | - Glenn Schattman
- Ronald O. Perelman and Claudia Cohen Center for Reproductive Medicine and Infertility, Weill Cornell Medicine, New York, NY 10065, USA
| | - Zev Rosenwaks
- Ronald O. Perelman and Claudia Cohen Center for Reproductive Medicine and Infertility, Weill Cornell Medicine, New York, NY 10065, USA
| | - Daylon James
- Ronald O. Perelman and Claudia Cohen Center for Reproductive Medicine and Infertility, Weill Cornell Medicine, New York, NY 10065, USA
- Tri-Institutional Stem Cell Derivation Laboratory, Weill Cornell Medicine, New York, NY 10065, USA
- Department of Obstetrics and Gynecology, Weill Cornell Medicine, New York, NY 10065, USA
| |
Collapse
|
8
|
Bale LK, Schafer MJ, Atkinson EJ, Le Brasseur NK, Haak AJ, Oxvig C, Conover CA. Pregnancy‐associated plasma protein‐A (PAPP‐A) is a key component of an interactive cellular mechanism promoting pulmonary fibrosis. J Cell Physiol 2022; 237:2220-2229. [PMID: 35098542 PMCID: PMC9050837 DOI: 10.1002/jcp.30687] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/19/2021] [Revised: 12/21/2021] [Accepted: 01/10/2022] [Indexed: 12/25/2022]
Abstract
Idiopathic pulmonary fibrosis (IPF) is a progressive lung disease with few effective treatment options. We found a highly significant correlation between pregnancy-associated plasma protein (PAPP)-A expression in IPF lung tissue and disease severity as measured by various pulmonary and physical function tests. PAPP-A is a metalloproteinase that enhances local insulin-like growth factor (IGF) activity. We used primary cultures of normal adult human lung fibroblasts (NHLF) to test the hypothesis that PAPP-A plays an important role in the development of pulmonary fibrosis. Treatment of NHLF with pro-fibrotic transforming growth factor (TGF)-β stimulated marked increases in IGF-I mRNA expression (>20-fold) and measurable IGF-I levels in 72-h conditioned medium (CM). TGF-β treatment also increased PAPP-A levels in CM fourfold (p = 0.004) and proteolytic activity ~2-fold. There was an indirect effect of TGF-β to stimulate signaling through the PI3K/Akt pathway, which was significantly inhibited by both IGF-I-inactivating and PAPP-A inhibitory antibodies. Induction of senescence in NHLF increased PAPP-A levels in CM 10-fold (p = 0.006) with attendant increased proteolytic activity. Thus, PAPP-A is a novel component of the senescent lung fibroblast secretome. In addition, NHLF secreted extracellular vehicles (EVs) with surface-bound active PAPP-A that were increased fivefold with senescence. Regulation of PAPP-A and IGF signaling by TGF-β and cell senescence suggests an interactive cellular mechanism underlying the resistance to apoptosis and the progression of fibrosis in IPF. Furthermore, PAPP-A-associated EVs may be a means of pro-fibrotic, pro-senescent communication with other cells in the lung and, thus, a potential therapeutic target for IPF.
Collapse
Affiliation(s)
- Laurie K. Bale
- Division of Endocrinology Metabolism and Nutrition, Endocrine Research Unit Rochester Minnesota USA
| | - Marissa J. Schafer
- Department of Physiology and Biomedical Engineering Rochester Minnesota USA
| | | | | | - Andrew J. Haak
- Department of Physiology and Biomedical Engineering Rochester Minnesota USA
| | - Claus Oxvig
- Department of Molecular Biology and Genetics University of Aarhus Aarhus Denmark
| | - Cheryl A. Conover
- Division of Endocrinology Metabolism and Nutrition, Endocrine Research Unit Rochester Minnesota USA
| |
Collapse
|
9
|
Mohrin M, Liu J, Zavala‐Solorio J, Bhargava S, Maxwell Trumble J, Brito A, Hu D, Brooks D, Koukos G, Alabdulaaly L, Paw JS, Hake K, Kolumam G, Bouxsein ML, Baron R, Kutskova Y, Freund A. Inhibition of longevity regulator PAPP-A modulates tissue homeostasis via restraint of mesenchymal stromal cells. Aging Cell 2021; 20:e13313. [PMID: 33561324 PMCID: PMC7963332 DOI: 10.1111/acel.13313] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/13/2020] [Revised: 11/08/2020] [Accepted: 12/31/2020] [Indexed: 12/20/2022] Open
Abstract
Pregnancy‐associated plasma protein‐A (PAPP‐A) is a secreted metalloprotease that increases insulin‐like growth factor (IGF) availability by cleaving IGF‐binding proteins. Reduced IGF signaling extends longevity in multiple species, and consistent with this, PAPP‐A deletion extends lifespan and healthspan; however, the mechanism remains unclear. To clarify PAPP‐A’s role, we developed a PAPP‐A neutralizing antibody and treated adult mice with it. Transcriptomic profiling across tissues showed that anti‐PAPP‐A reduced IGF signaling and extracellular matrix (ECM) gene expression system wide. The greatest reduction in IGF signaling occurred in the bone marrow, where we found reduced bone, marrow adiposity, and myelopoiesis. These diverse effects led us to search for unifying mechanisms. We identified mesenchymal stromal cells (MSCs) as the source of PAPP‐A in bone marrow and primary responders to PAPP‐A inhibition. Mice treated with anti‐PAPP‐A had reduced IGF signaling in MSCs and dramatically decreased MSC number. As MSCs are (1) a major source of ECM and the progenitors of ECM‐producing fibroblasts, (2) the originating source of adult bone, (3) regulators of marrow adiposity, and (4) an essential component of the hematopoietic niche, our data suggest that PAPP‐A modulates bone marrow homeostasis by potentiating the number and activity of MSCs. We found that MSC‐like cells are the major source of PAPP‐A in other tissues also, suggesting that reduced MSC‐like cell activity drives the system‐wide reduction in ECM gene expression due to PAPP‐A inhibition. Dysregulated ECM production is associated with aging and drives age‐related diseases, and thus, this may be a mechanism by which PAPP‐A deficiency enhances longevity.
Collapse
Affiliation(s)
- Mary Mohrin
- Calico Life Sciences LLC South San Francisco CA USA
| | - Justin Liu
- Calico Life Sciences LLC South San Francisco CA USA
| | | | | | | | | | - Dorothy Hu
- Harvard School of Dental Medicine Boston MA USA
| | - Daniel Brooks
- Center for Advanced Orthopaedic Studies Beth Israel Deaconess Medical Center Boston MA USA
| | | | | | | | - Kayley Hake
- Calico Life Sciences LLC South San Francisco CA USA
| | | | - Mary L. Bouxsein
- Center for Advanced Orthopaedic Studies Beth Israel Deaconess Medical Center Boston MA USA
- Harvard Medical School Boston MA USA
| | - Roland Baron
- Harvard School of Dental Medicine Boston MA USA
- Harvard Medical School Boston MA USA
| | | | - Adam Freund
- Calico Life Sciences LLC South San Francisco CA USA
| |
Collapse
|
10
|
Kashyap S, Zeidler JD, Chini CCS, Chini EN. Implications of the PAPP-A-IGFBP-IGF-1 pathway in the pathogenesis and treatment of polycystic kidney disease. Cell Signal 2020; 73:109698. [PMID: 32569826 DOI: 10.1016/j.cellsig.2020.109698] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/01/2020] [Revised: 06/17/2020] [Accepted: 06/18/2020] [Indexed: 12/19/2022]
Abstract
Autosomal dominant polycystic kidney disease (ADPKD) is one of the most common genetic diseases implicated in the development of end stage renal disease (ESRD). Although FDA has recently approved a drug against ADPKD, there is still a great need for development of alternative management strategies for ADPKD. Understanding the different mechanisms that lead to cystogenesis and cyst expansion in ADPKD is imperative to develop new therapies against ADPKD. Recently, we demonstrated that caloric restriction can prevent the development of cystic disease in animal models of ADPKD and through these studies identified a new role for pregnancy associated plasma protein-A (PAPP-A), a component of the insulin-like growth factors (IGF) pathway, in the pathogenesis of this disease. The PAPP-A-IGF pathway plays an important role in regulation of cell growth, differentiation, and transformation and dysregulation of this pathway has been implicated in many diseases. Several indirect studies support the involvement of IGF-1 in the pathogenesis of ADPKD. However, it was only recently that we described a direct role for a component of this pathway in pathogenesis of ADPKD, opening a new avenue for the therapeutic approaches for this cystic disease. The present literature review will critically discuss the evidence that supports the role of components of IGF pathway in the pathogenesis of ADPKD and discuss the pharmacological implications of PAPP-A-IGF axis in this disease.
Collapse
Affiliation(s)
- Sonu Kashyap
- Signal Transduction and Molecular Nutrition Laboratory, Kogod Aging Center, Department of Anesthesiology and Perioperative Medicine, Mayo Clinic College of Medicine, Rochester, MN 55905, USA
| | - Julianna D Zeidler
- Signal Transduction and Molecular Nutrition Laboratory, Kogod Aging Center, Department of Anesthesiology and Perioperative Medicine, Mayo Clinic College of Medicine, Rochester, MN 55905, USA
| | - Claudia C S Chini
- Signal Transduction and Molecular Nutrition Laboratory, Kogod Aging Center, Department of Anesthesiology and Perioperative Medicine, Mayo Clinic College of Medicine, Rochester, MN 55905, USA
| | - Eduardo Nunes Chini
- Signal Transduction and Molecular Nutrition Laboratory, Kogod Aging Center, Department of Anesthesiology and Perioperative Medicine, Mayo Clinic College of Medicine, Rochester, MN 55905, USA.
| |
Collapse
|
11
|
Liu C, Li S, Noer PR, Kjaer-Sorensen K, Juhl AK, Goldstein A, Ke C, Oxvig C, Duan C. The metalloproteinase Papp-aa controls epithelial cell quiescence-proliferation transition. eLife 2020; 9:e52322. [PMID: 32293560 PMCID: PMC7185994 DOI: 10.7554/elife.52322] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/30/2019] [Accepted: 04/11/2020] [Indexed: 02/06/2023] Open
Abstract
Human patients carrying PAPP-A2 inactivating mutations have low bone mineral density. The underlying mechanisms for this reduced calcification are poorly understood. Using a zebrafish model, we report that Papp-aa regulates bone calcification by promoting Ca2+-transporting epithelial cell (ionocyte) quiescence-proliferation transition. Ionocytes, which are normally quiescent, re-enter the cell cycle under low [Ca2+] stress. Genetic deletion of Papp-aa, but not the closely related Papp-ab, abolished ionocyte proliferation and reduced calcified bone mass. Loss of Papp-aa expression or activity resulted in diminished IGF1 receptor-Akt-Tor signaling in ionocytes. Under low Ca2+ stress, Papp-aa cleaved Igfbp5a. Under normal conditions, however, Papp-aa proteinase activity was suppressed and IGFs were sequestered in the IGF/Igfbp complex. Pharmacological disruption of the IGF/Igfbp complex or adding free IGF1 activated IGF signaling and promoted ionocyte proliferation. These findings suggest that Papp-aa-mediated local Igfbp5a cleavage functions as a [Ca2+]-regulated molecular switch linking IGF signaling to bone calcification by stimulating epithelial cell quiescence-proliferation transition under low Ca2+ stress.
Collapse
Affiliation(s)
- Chengdong Liu
- Department of Molecular, Cellular, and Developmental Biology, University of Michigan, Ann Arbor, United States
| | - Shuang Li
- Department of Molecular, Cellular, and Developmental Biology, University of Michigan, Ann Arbor, United States
- College of Ocean and Earth Sciences, Xiamen University, Xiamen, China
| | - Pernille Rimmer Noer
- Department of Molecular Biology and Genetics, Aarhus University, Aarhus, Denmark
| | | | - Anna Karina Juhl
- Department of Molecular Biology and Genetics, Aarhus University, Aarhus, Denmark
| | - Allison Goldstein
- Department of Molecular, Cellular, and Developmental Biology, University of Michigan, Ann Arbor, United States
| | - Caihuan Ke
- College of Ocean and Earth Sciences, Xiamen University, Xiamen, China
| | - Claus Oxvig
- Department of Molecular Biology and Genetics, Aarhus University, Aarhus, Denmark
| | - Cunming Duan
- Department of Molecular, Cellular, and Developmental Biology, University of Michigan, Ann Arbor, United States
| |
Collapse
|
12
|
Fan SY, Chiu NF, Chen CP, Chang CC, Chen CY. Simultaneous Real-Time Detection of Pregnancy-Associated Plasma Protein-A and -A2 Using a Graphene Oxide-Based Surface Plasmon Resonance Biosensor. Int J Nanomedicine 2020; 15:2085-2094. [PMID: 32273704 PMCID: PMC7105368 DOI: 10.2147/ijn.s237938] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/09/2019] [Accepted: 03/12/2020] [Indexed: 12/26/2022] Open
Abstract
Background Pregnancy-associated plasma protein-A and -A2 (PAPP-A and -A2) are principally expressed in placental trophoblasts and play a critical role in the regulation of fetal and placental growth. PAPP-A2 shares 45% amino acid similarity with PAPP-A. This study aimed to investigate the efficacy of real-time detection of PAPP-A and PAPP-A2 using a novel surface plasmon resonance (SPR) biosensor based on graphene oxide (GO). Methods Traditional SPR and GO-based SPR chips were fabricated to measure PAPP-A and PAPP-A2 concentrations. We compared SPR response curves of PAPP-A and PAPP-A2 between traditional SPR and GO-SPR biosensors. We also performed interference tests and specificity analyses among PAPP-A, PAPP-A2, and mixed interference proteins. Results The time to detect PAPP-A and PAPP-A2 was about 150 seconds with both traditional SPR and GO-SPR biosensors. Approximately double SPR angle shifts were noted with the GO-SPR biosensor compared to the traditional SPR biosensor at a PAPP-A and PAPP-A2 concentration of 5 μg/mL. The limit of detection of the GO-SPR biosensor was as low as 0.5 ng/mL for both PAPP-A and PAPP-A2. Interference testing revealed that almost all of the protein bonded on the GO-SPR biosensor with anti-PAPP-A from the mixture of proteins was PAPP-A, and that almost no other proteins were captured except for PAPP-A2. However, the SPR signal of PAPP-A2 (5.75 mdeg) was much smaller than that of PAPP-A (13.76 mdeg). Similar results were noted with anti-PAPP-A2, where almost all of the protein bonded on the GO-SPR biosensor was PAPP-A2. The SPR signal of PAPP-A (5.17 mdeg) was much smaller than that of PAPP-A2 (13.94 mdeg). Conclusion The GO-SPR biosensor could distinguish PAPP-A and PAPP-A2 from various mixed interference proteins with high sensitivity and specificity. It could potentially be used to measure PAPP-A and PAPP-A2 in clinical blood samples during pregnancy.
Collapse
Affiliation(s)
- Shi-Yuan Fan
- Department of Obstetrics and Gynecology, Mackay Memorial Hospital, Taipei, Taiwan
| | - Nan-Fu Chiu
- Institute of Electro-Optical Science and Technology, National Taiwan Normal University, Taipei, Taiwan
| | - Chie-Pein Chen
- Department of Obstetrics and Gynecology, Mackay Memorial Hospital, Taipei, Taiwan.,Department of Medicine, Mackay Medical College, New Taipei City, Taiwan
| | - Chia-Chen Chang
- Department of Medical Biotechnology and Laboratory Science, Chang Gung University, Taoyuan City, Taiwan
| | - Chen-Yu Chen
- Department of Obstetrics and Gynecology, Mackay Memorial Hospital, Taipei, Taiwan.,Department of Medicine, Mackay Medical College, New Taipei City, Taiwan
| |
Collapse
|
13
|
Torres D, Hou X, Bale L, Heinzen EP, Maurer MJ, Zanfagnin V, Oberg AL, Conover C, Weroha SJ. Overcoming platinum resistance in ovarian cancer by targeting pregnancy-associated plasma protein-A. PLoS One 2019; 14:e0224564. [PMID: 31751381 PMCID: PMC6872139 DOI: 10.1371/journal.pone.0224564] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/06/2019] [Accepted: 10/16/2019] [Indexed: 12/13/2022] Open
Abstract
OBJECTIVES Inhibition of pregnancy-associated plasma protein-A (PAPP-A), an upstream activator of the insulin-like growth factor (IGF) pathway, is known to augment sensitivity to platinum-based chemotherapy. This study further tests the efficacy of PAPP-A inhibition with a monoclonal antibody inhibitor (mAb-PA) in ovarian cancer (OC) platinum-resistant patient-derived xenograft (PDX) models. METHODS PAPP-A expression was quantitated in platinum-resistant PDX models by ELISA. A subset with High (n = 5) and Low (n = 2) expression were revived in female SCID/beige mice for studies with either saline, carboplatin/paclitaxel (CP) + mAb-PA, or CP + IgG2a. The primary endpoint was tumor area by ultrasound on day 28 relative to baseline. Conversion to platinum-sensitive was defined by average tumor regression below baseline. Statistical analyses included linear mixed effects modeling and Kaplan Meier curves. Response to therapy was correlated with changes in the ratio of phosphorylated/total AKT and ERK 1/2 using Wes analysis. RESULTS The addition of mAb-PA to CP induced tumor regression below baseline in one High PAPP-A PDX model; another three models exhibited notable growth inhibition relative to CP + IgG2a. None of the Low PAPP-A PDX models regressed below baseline. The PDX model with the greatest magnitude of tumor regression from baseline after combination therapy was maintained on single agent mAb-PA or IgG2a, but no benefit was observed. Decreased phosphorylation of ERK1/2 correlated with conversion to platinum-sensitive. CONCLUSIONS The addition of mAb-PA to CP overcame platinum-resistance in one of five High PAPP-A PDX models; three other models demonstrated improved platinum-response. This supports further clinical development of this novel therapeutic.
Collapse
Affiliation(s)
- Diogo Torres
- Department of Obstetrics and Gynecology, Division of Gynecologic Surgery, Mayo Clinic, Rochester, MN, United States
| | - Xiaonan Hou
- Department of Oncology, Division of Medical Oncology, Mayo Clinic, Rochester, MN, United States
| | - Laurie Bale
- Division of Endocrinology, Mayo Clinic, Rochester, MN, United States
| | - Ethan P. Heinzen
- Department of Health Science Research, Division of Biomedical Statistics and Informatics, Rochester, MN, United States
| | - Matthew J. Maurer
- Department of Health Science Research, Division of Biomedical Statistics and Informatics, Rochester, MN, United States
| | - Valentina Zanfagnin
- Department of Oncology, Division of Medical Oncology, Mayo Clinic, Rochester, MN, United States
| | - Ann L. Oberg
- Department of Health Science Research, Division of Biomedical Statistics and Informatics, Rochester, MN, United States
| | - Cheryl Conover
- Division of Endocrinology, Mayo Clinic, Rochester, MN, United States
| | - S. John Weroha
- Department of Oncology, Division of Medical Oncology, Mayo Clinic, Rochester, MN, United States
- * E-mail:
| |
Collapse
|
14
|
Conover CA, Bale LK, Frye RL, Schaff HV. Cellular characterization of human epicardial adipose tissue: highly expressed PAPP-A regulates insulin-like growth factor I signaling in human cardiomyocytes. Physiol Rep 2019; 7:e14006. [PMID: 30809969 PMCID: PMC6391584 DOI: 10.14814/phy2.14006] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/22/2019] [Revised: 01/23/2019] [Accepted: 01/28/2019] [Indexed: 12/16/2022] Open
Abstract
Little is known about the cellular biology of fat surrounding the human heart. In this study, we obtained paired samples of epicardial fat, the visceral fat depot attached to the heart, and subcutaneous skin fat from patients undergoing open heart surgery to test the hypothesis that human epicardial fat cells differentially express bioactive molecules that have the potential to affect cardiac function. First, we characterized the free fatty acids (FFAs), adipocytokines, and growth factors secreted by isolated adipocytes and preadipocytes in cell culture. There was little to distinguish the fat cell secretory products in terms of FFAs and adipocytokines. The most striking finding was that preadipocytes from epicardial adipose tissue expressed high levels of pregnancy-associated plasma protein-A (PAPP-A), a novel metalloproteinase that enhances local insulin-like growth factor (IGF) action through cleavage of inhibitory IGF binding protein-4 (IGFBP-4). PAPP-A levels were 15-fold higher in conditioned medium from epicardial preadipocytes than from subcutaneous preadipocytes (P < 0.0001). PAPP-A was not expressed in mature adipocytes. Next we determined whether PAPP-A could affect IGF-I signaling in a human cardiomyocyte cell line. IGF-I activated receptor-mediated auto-phosphorylation, and this was blocked by wild-type and protease-resistant IGFBP-4. Addition of PAPP-A induced cleavage of wild-type, but not protease-resistant, IGFBP-4 thereby restoring IGF-I action. A proteolytically defective PAPP-A had no effect. IGF-I receptor-mediated signaling through the phosphatidylinositol 3-kinase pathway was similarly inhibited by IGFBP-4 and restored by PAPP-A. Thus, human epicardial fat cells differentially express PAPP-A, which has the potential to affect IGF signaling in the heart.
Collapse
Affiliation(s)
| | | | - Robert L. Frye
- Department of Cardiovascular DiseasesMayo ClinicRochesterMinnesota
| | | |
Collapse
|
15
|
Crucial residues in falcipains that mediate hemoglobin hydrolysis. Exp Parasitol 2019; 197:43-50. [PMID: 30648557 DOI: 10.1016/j.exppara.2019.01.005] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/19/2018] [Revised: 11/03/2018] [Accepted: 01/11/2019] [Indexed: 02/08/2023]
|
16
|
Hjortebjerg R. IGFBP-4 and PAPP-A in normal physiology and disease. Growth Horm IGF Res 2018; 41:7-22. [PMID: 29864720 DOI: 10.1016/j.ghir.2018.05.002] [Citation(s) in RCA: 41] [Impact Index Per Article: 6.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/27/2018] [Revised: 05/15/2018] [Accepted: 05/29/2018] [Indexed: 02/07/2023]
Abstract
Insulin-like growth factor (IGF) binding protein-4 (IGFBP-4) is a modulator of the IGF system, exerting both inhibitory and stimulatory effects on IGF-induced cellular growth. IGFBP-4 is the principal substrate for the enzyme pregnancy-associated plasma protein-A (PAPP-A). Through IGF-dependent cleavage of IGFBP-4 in the vicinity of the IGF receptor, PAPP-A is able to increase IGF bioavailability and stimulate IGF-mediated growth. Recently, the stanniocalcins (STCs) were identified as novel inhibitors of PAPP-A proteolytic activity, hereby adding additional members to the seemingly endless list of proteins belonging to the IGF family. Our understanding of these proteins has advanced throughout recent years, and there is evidence to suggest that the role of IGFBP-4 and PAPP-A in defining the relationship between total IGF and IGF bioactivity can be linked to a number of pathological conditions. This review provides an overview of the experimental and clinical findings on the IGFBP-4/PAPP-A/STC axis as a regulator of IGF activity and examines the conundrum surrounding extrapolation of circulating concentrations to tissue action of these proteins. The primary focus will be on the biological significance of IGFBP-4 and PAPP-A in normal physiology and in pathophysiology with emphasis on metabolic disorders, cardiovascular diseases, and cancer. Finally, the review assesses current new trajectories of IGFBP-4 and PAPP-A research.
Collapse
Affiliation(s)
- Rikke Hjortebjerg
- Medical Research Laboratory, Department of Clinical Medicine, Faculty of Health, Aarhus University, Aarhus, Denmark; The Danish Diabetes Academy, Odense, Denmark.
| |
Collapse
|
17
|
Abstract
The zinc metalloproteinase, PAPP-A, enhances local insulin-like growth factor (IGF) action through cleavage of inhibitory IGF-binding proteins, thereby increasing IGF available for IGF receptor-mediated cell proliferation, migration and survival. In many tumors, enhanced IGF receptor signaling is associated with tumor growth, invasion and metastasis. We will first discuss PAPP-A structure and function, and post-translational inhibitors of PAPP-A expression or proteolytic activity. We will then review the evidence supporting an important role for PAPP-A in many cancers, including breast, ovarian and lung cancer, and Ewing sarcoma.
Collapse
Affiliation(s)
- Cheryl A Conover
- From the Division of Endocrinology Mayo ClinicRochester, Minnesota, USA
| | - Claus Oxvig
- Department of Molecular Biology and GeneticsAarhus University, Aarhus, Denmark
| |
Collapse
|
18
|
Santamaria S, de Groot R. Monoclonal antibodies against metzincin targets. Br J Pharmacol 2018; 176:52-66. [PMID: 29488211 DOI: 10.1111/bph.14186] [Citation(s) in RCA: 34] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/02/2018] [Revised: 02/13/2018] [Accepted: 02/16/2018] [Indexed: 12/12/2022] Open
Abstract
The metzincin clan of metalloproteinases includes the MMP, disintegrin and metalloproteinase (ADAM) and ADAM with thrombospondin motifs families, which cleave extracellular targets in a wide range of (patho)physiological processes. Antibodies constitute a powerful tool to modulate the activity of these enzymes for both therapeutic and research purposes. In this review, we give an overview of monoclonal antibodies (mAbs) that have been tested in preclinical disease models, human trials and important studies of metzincin structure and function. Initial attempts to develop therapeutic small molecule inhibitors against MMPs were hampered by structural similarities between metzincin active sites and, consequently, off-target effects. Therefore, more recently, mAbs have been developed that do not bind to the active site but bind to surface-exposed loops that are poorly conserved in closely related family members. Inhibition of protease activity by these mAbs occurs through a variety of mechanisms, including (i) barring access to the active site, (ii) disruption of exosite binding, and (iii) prevention of protease activation. These different modes of inhibition are discussed in the context of the antibodies' potency, selectivity and, importantly, the effects in models of disease and clinical trials. In addition, various innovative strategies that were used to generate anti-metzincin mAbs are discussed. LINKED ARTICLES: This article is part of a themed section on Translating the Matrix. To view the other articles in this section visit http://onlinelibrary.wiley.com/doi/10.1111/bph.v176.1/issuetoc.
Collapse
Affiliation(s)
| | - Rens de Groot
- Imperial College London, Centre for Haematology, London, UK
| |
Collapse
|
19
|
Conover CA, Oxvig C. PAPP-A: a promising therapeutic target for healthy longevity. Aging Cell 2017; 16:205-209. [PMID: 28035757 PMCID: PMC5334524 DOI: 10.1111/acel.12564] [Citation(s) in RCA: 23] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 11/25/2016] [Indexed: 12/16/2022] Open
Abstract
Pregnancy-associated plasma protein-A (PAPP-A) is a proteolytic enzyme that was discovered to increase local insulin-like growth factor (IGF) availability for receptor activation through cleavage of inhibitory IGF binding proteins (IGFBPs). Reduced IGF signaling has been associated with increased lifespan and healthspan. Therefore, inhibition of PAPP-A represents a novel approach to indirectly decrease the availability of bioactive IGF. Here, we will review data in support of PAPP-A as a therapeutic target to promote healthy longevity.
Collapse
Affiliation(s)
| | - Claus Oxvig
- Department of Molecular Biology and Genetics; Aarhus Universitet; Aarhus Denmark
| |
Collapse
|
20
|
Mikkelsen JH, Resch ZT, Kalra B, Savjani G, Kumar A, Conover CA, Oxvig C. Indirect targeting of IGF receptor signaling in vivo by substrate-selective inhibition of PAPP-A proteolytic activity. Oncotarget 2015; 5:1014-25. [PMID: 24572990 PMCID: PMC4011579 DOI: 10.18632/oncotarget.1629] [Citation(s) in RCA: 43] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/08/2023] Open
Abstract
The insulin-like growth factor (IGF) signaling pathway is involved in certain human cancers, and the feasibility of directly targeting the IGF receptor has been actively investigated. However, recent evidence from clinical trials suggests that this approach can be problematic. We have developed an alternative strategy to indirectly inhibit the IGF signaling by targeting the metalloproteinase, pregnancy-associated plasma protein-A (PAPP-A). PAPP-A associated with the cell surface cleaves IGF binding protein-4 (IGFBP-4), when IGF is bound to IGFBP-4, and thereby increases IGF bioavailability for receptor activation in an autocrine/paracrine manner. We hypothesized that inhibition of PAPP-A would suppress excessive local IGF signaling in tissues where this is caused by increased PAPP-A proteolytic activity. To test this hypothesis, we developed an inhibitory monoclonal antibody, mAb 1/41, which targets a unique substrate-binding exosite of PAPP-A. This inhibitor selectively and specifically inhibits proteolytic cleavage of IGFBP-4 with an inhibitory constant (Ki) of 135 pM. In addition, it inhibited intracellular signaling of the IGF receptor (AKT phosphorylation) in monolayers of A549 cells, an IGF-responsive lung cancer-derived cell line found to express high levels of PAPP-A. We further showed that mAb 1/41 is effective towards PAPP-A bound to cell surfaces, and that it is capable of inhibiting PAPP-A activity in vivo. Using a murine xenograft model of A549 cells, we demonstrated that mAb 1/41 administered intraperitoneally significantly inhibited tumor growth. Analysis of xenograft tumor tissue recovered from treated mice showed penetration of mAb 1/41, reduced IGFBP-4 proteolysis, and reduced AKT phosphorylation. Our study provides proof of concept that IGF signaling can be selectively reduced by targeting a regulatory proteinase that functions extracellularly, upstream of the IGF receptor. PAPP-A targeting thus represents an alternative therapeutic strategy for inhibiting IGF receptor signaling.
Collapse
Affiliation(s)
- Jakob H Mikkelsen
- Department of Molecular Biology and Genetics, University of Aarhus, DK-8000 Aarhus C, Denmark
| | | | | | | | | | | | | |
Collapse
|
21
|
Becker MA, Haluska P, Bale LK, Oxvig C, Conover CA. A novel neutralizing antibody targeting pregnancy-associated plasma protein-a inhibits ovarian cancer growth and ascites accumulation in patient mouse tumorgrafts. Mol Cancer Ther 2015; 14:973-81. [PMID: 25695953 DOI: 10.1158/1535-7163.mct-14-0880] [Citation(s) in RCA: 39] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/08/2014] [Accepted: 02/10/2015] [Indexed: 12/16/2022]
Abstract
The majority of ovarian cancer patients acquire resistance to standard platinum chemotherapy and novel therapies to reduce tumor burden and ascites accumulation are needed. Pregnancy-associated plasma protein-A (PAPP-A) plays a key role in promoting insulin-like growth factor (IGF) pathway activity, which directly correlates to ovarian cancer cell transformation, growth, and invasiveness. Herein, we evaluate PAPP-A expression in tumors and ascites of women with ovarian cancer, and determine the antitumor efficacy of a neutralizing monoclonal PAPP-A antibody (mAb-PA) in ovarian cancer using primary patient ovarian tumorgrafts ("Ovatars"). PAPP-A mRNA expression in patient ovarian tumors correlated with poor outcome and was validated as a prognostic surrogate in Ovatar tumors. Following confirmation of mAb-PA bioavailability and target efficacy in vivo, the antitumor efficacy of mAb-PA in multiple Ovatar tumor models was examined and the response was found to depend on PAPP-A expression. Strikingly, the addition of mAb-PA to standard platinum chemotherapy effectively sensitized platinum-resistant Ovatar tumors. PAPP-A protein in ascites was also assessed in a large cohort of patients and very high levels were evident across the entire sample set. Therefore, we evaluated targeted PAPP-A inhibition as a novel approach to managing ovarian ascites, and found that mAb-PA inhibited the development, attenuated the progression, and induced the regression of Ovatar ascites. Together, these data indicate PAPP-A as a potential palliative and adjunct therapeutic target for women with ovarian cancer.
Collapse
Affiliation(s)
- Marc A Becker
- Division of Medical Oncology, Mayo Clinic, Rochester, Minnesota
| | - Paul Haluska
- Division of Medical Oncology, Mayo Clinic, Rochester, Minnesota
| | - Laurie K Bale
- Division of Endocrinology, Mayo Clinic, Rochester, Minnesota
| | - Claus Oxvig
- Department of Molecular Biology and Genetics, Aarhus University, Aarhus, Denmark
| | | |
Collapse
|
22
|
The role of PAPP-A in the IGF system: location, location, location. J Cell Commun Signal 2015; 9:177-87. [PMID: 25617049 DOI: 10.1007/s12079-015-0259-9] [Citation(s) in RCA: 127] [Impact Index Per Article: 14.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/23/2014] [Accepted: 01/12/2015] [Indexed: 12/15/2022] Open
Abstract
Although discovered as a placental protein present abundantly in the circulation of pregnant women, pregnancy-associated plasma protein-A (PAPP-A) is widely expressed in multiple tissues. PAPP-A is a highly specific metalloproteinase binding tightly to glycosaminoglycans present on the surface of cells. By cleaving a subset of insulin-like growth factor binding proteins (IGFBPs), PAPP-A thus functions within tissues as a growth-promoting enzyme, releasing bioactive IGF in close proximity to the IGF receptor. IGFBP-4 is believed to be the principal PAPP-A substrate, and the focus in this review is on PAPP-A enzymatic activity and its role in the PAPP-A-IGFBP-4-IGF axis, which is subject to regulation at several different levels. These include e.g., transcriptional control, competing reactions potentially sequestering IGF from IGFBP-4 and hence antagonizing PAPP-A-mediated IGF activation, and proteolytic inhibition of PAPP-A. The latter may involve the protein stanniocalcin-2 (STC2), recently found to potently inhibit PAPP-A activity by forming a covalent complex with PAPP-A. PAPP-A or complex-bound variants may escape from pathological tissues into the circulation. It is emphasized that the potential use of PAPP-A as a diagnostic or predictive biomarker in nonpregnant individuals requires precise knowledge of analyte identity and assay specificity in addition to an appropriate material for standardization. Finally, PAPP-A may serve as a therapeutic target to indirectly inhibit IGF signaling in tissues where this is driven by increased PAPP-A activity. By taking advantage of the intricate interaction between PAPP-A and IGFBP-4, highly specific and selective inhibition of PAPP-A is possible.
Collapse
|
23
|
Identification of exosite-targeting inhibitors of anthrax lethal factor by high-throughput screening. ACTA ACUST UNITED AC 2014; 19:875-82. [PMID: 22840775 DOI: 10.1016/j.chembiol.2012.05.013] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/07/2012] [Revised: 05/10/2012] [Accepted: 05/17/2012] [Indexed: 12/24/2022]
Abstract
Protease inhibitor discovery has focused almost exclusively on compounds that bind to the active site. Inhibitors targeting protease exosites, regions outside of the active site that influence catalysis, offer potential advantages of increased specificity but are difficult to systematically discover. Here, we describe an assay suitable for detecting exosite-targeting inhibitors of the metalloproteinase anthrax lethal factor (LF) based on cleavage of a full-length mitogen-activated protein kinase kinase (MKK) substrate. We used this assay to screen a small-molecule library and then subjected hits to a secondary screen to exclude compounds that efficiently blocked cleavage of a peptide substrate. We identified a compound that preferentially inhibited cleavage of MKKs compared with peptide substrates and could suppress LF-induced macrophage cytolysis. This approach should be generally applicable to the discovery of exosite-targeting inhibitors of many additional proteases.
Collapse
|
24
|
Kjaer-Sorensen K, Engholm DH, Jepsen MR, Morch MG, Weyer K, Hefting LL, Skov LL, Laursen LS, Oxvig C. Pregnancy-associated plasma protein-A2 modulates development of cranial cartilage and angiogenesis in zebrafish embryos. J Cell Sci 2014; 127:5027-37. [DOI: 10.1242/jcs.152587] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/24/2022] Open
Abstract
Pregnancy-associated plasma protein-A2 (PAPP-A2, pappalysin-2) is a large metalloproteinase, known to be required for normal postnatal growth and bone development in mice. We here report the detection of zebrafish papp-a2 mRNA in chordamesoderm, notochord, and lower jaw of zebrafish (Danio rerio) embryos, and that papp-a2 knockdown embryos display broadened axial mesoderm, notochord bends, and severely reduced cranial cartilages. Genetic data link these phenotypes to insulin-like growth factor binding protein-3 (Igfbp-3) and Bmp signaling, and biochemical analysis show specific Igfbp-3 proteolysis by Papp-a2, implicating Papp-a2 in the modulation of Bmp signaling by Igfbp-3 proteolysis. Knockdown of papp-a2 additionally resulted in angiogenesis defects, strikingly similar to previous observations in embryos with mutations in components of the Notch system. Concordantly, we find that Notch signaling is modulated by Papp-a2 in vivo, and, furthermore, that PAPP-A2 is capable of modulating Notch signaling independently of its proteolytic activity in cell culture. Based on these results, we conclude that Papp-a2 modulates Bmp and Notch signaling by independent mechanisms in zebrafish embryos. In conclusion, these data link pappalysin function in zebrafish to two different signaling pathways outside the IGF system.
Collapse
|
25
|
Mikkelsen JH, Steffensen LB, Oxvig C. Development of a recombinant antibody towards PAPP-A for immunohistochemical use in multiple animal species. J Immunol Methods 2013; 404:33-40. [PMID: 24333852 DOI: 10.1016/j.jim.2013.12.002] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/04/2013] [Revised: 12/04/2013] [Accepted: 12/05/2013] [Indexed: 10/25/2022]
Abstract
The metalloproteinase, pregnancy-associated plasma protein-A (PAPP-A), is increasingly recognized as a modulator of insulin-like growth factor (IGF) signaling; it cleaves IGF binding proteins causing the release of bioactive IGF. Accumulating evidence supports an important role of PAPP-A in both normal physiology and under different pathological conditions. However, antibodies for the detection of PAPP-A in non-human tissues have been lacking, although needed for use with several animal models which are currently being developed. To develop a monoclonal antibody suitable for the immunohistochemical detection of PAPP-A, we therefore selected a phage-derived scFv antibody, PAC1, specifically recognizing an epitope of PAPP-A, which is highly conserved between multiple animal species. We first converted this antibody into bivalent IgG, and verified its ability to recognize PAPP-A in sections of formalin-fixed and paraffin-embedded tissue. For increased sensitivity, affinity maturation to sub-nanomolar affinity was then carried out. The resulting recombinant antibody, PAC1-D8-mIgG2a, detects PAPP-A specifically and sensitively in human tissue. In addition, this antibody allows detection of PAPP-A in non-human species. We demonstrate its usefulness for the visualization of PAPP-A in murine and porcine tissues.
Collapse
Affiliation(s)
- Jakob H Mikkelsen
- Department of Molecular Biology and Genetics, Aarhus University, Gustav Wieds Vej 10C, DK-8000 Aarhus C, Denmark
| | - Lasse B Steffensen
- Department of Molecular Biology and Genetics, Aarhus University, Gustav Wieds Vej 10C, DK-8000 Aarhus C, Denmark
| | - Claus Oxvig
- Department of Molecular Biology and Genetics, Aarhus University, Gustav Wieds Vej 10C, DK-8000 Aarhus C, Denmark.
| |
Collapse
|
26
|
Hjortebjerg R, Flyvbjerg A, Frystyk J. Insulin growth factor binding proteins as therapeutic targets in type 2 diabetes. Expert Opin Ther Targets 2013; 18:209-24. [PMID: 24261835 DOI: 10.1517/14728222.2014.858698] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/01/2023]
Abstract
INTRODUCTION The signaling pathways of the insulin-like growth factors (IGFs) have been implicated in the aetiology of type 2 diabetes (T2D) and a number of therapeutic modalities aiming at the IGF-axis have been considered. Administration of IGF-I has been reported to improve insulin sensitivity in healthy subjects and patients with T2D. In recent years, the IGF binding proteins (IGFBPs) have also been associated with metabolic disorders, prompting the idea that IGFBPs play important roles in the pathogenesis of T2D. Thus, by virtue of their role in the regulation of IGF effects, the IGFBPs have emerged as potential biomarkers and therapeutic targets in metabolic syndromes and T2D. AREAS COVERED The article provides an overview on recent findings in clinical and experimental IGFBP-research and addresses the studies that have investigated the potentials of the IGFBPs as therapeutic targets in T2D. EXPERT OPINION There is plenty of therapeutic promise within the IGF system, but further understanding of the IGFs in T2D is necessary to avoid off-target effects. Strong evidence supports the use of IGFBPs as therapeutic targets in the treatment of T2D, and it is not difficult to foresee the use of IGFBPs as part of a combination therapy alongside other anti-diabetic drugs.
Collapse
Affiliation(s)
- Rikke Hjortebjerg
- Aarhus University, Department of Clinical Medicine, Medical Research Laboratory, Faculty of Health , DK-8000 Aarhus C , Denmark
| | | | | |
Collapse
|
27
|
Wang W, Liu Y, Lazarus RA. Allosteric inhibition of BACE1 by an exosite-binding antibody. Curr Opin Struct Biol 2013; 23:797-805. [PMID: 23998983 DOI: 10.1016/j.sbi.2013.08.001] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/19/2013] [Revised: 07/24/2013] [Accepted: 08/07/2013] [Indexed: 01/14/2023]
Abstract
β-Secretase (BACE1) is a membrane-anchored pepsin-like aspartic protease and is the rate-limiting enzyme in the β-amyloidogenic pathway. Thus, inhibitors of BACE1 activity have therapeutic potential for Alzheimer's disease. While much effort has focused on small molecule active site inhibitors, recent exploration of BACE1 inhibition by peptides and antibodies has revealed exosites that can regulate enzymatic activity. This type of allosteric regulation by proteinaceous factors, while frequently found in serine and cysteine proteases, is rarely seen in aspartic proteases. A crystal structure of the anti-BACE1/enzyme complex shows altered structural features and dynamic characteristics near the substrate-binding cleft. This binding mode, along with the enzymatic inhibition pattern, suggests that anti-BACE1 functions through an allosteric inhibition mechanism.
Collapse
Affiliation(s)
- Weiru Wang
- Department of Structural Biology, Genentech, Inc., 1 DNA Way, South San Francisco, CA 94080, United States.
| | | | | |
Collapse
|
28
|
Kløverpris S, Gaidamauskas E, Rasmussen LCV, Overgaard MT, Kronborg C, Knudsen UB, Christiansen M, Kumar A, Oxvig C. A robust immunoassay for pregnancy-associated plasma protein-A2 based on analysis of circulating antigen: establishment of normal ranges in pregnancy. Mol Hum Reprod 2013; 19:756-63. [PMID: 23804707 DOI: 10.1093/molehr/gat047] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/22/2022] Open
Abstract
Pregnancy-associated plasma protein-A (PAPP-A) and PAPP-A2, two homologous metzincin metalloproteases, are both tightly linked to regulation within the insulin-like growth factor (IGF) system because of their specific cleavage of IGF binding proteins. Recent studies suggest that PAPP-A may be involved in clinical conditions related to unwanted cellular growth, and the circulating levels of PAPP-A is an established biomarker in prenatal screening for chromosomal abnormalities. Microarray data indicate that PAPP-A2 has potential as a biomarker for pre-eclampsia. However, well-characterized immunological methods of quantification are not available. We therefore developed monoclonal antibodies against recombinant PAPP-A2. The antibodies were epitope mapped against recombinantly expressed chimeras between PAPP-A2 and PAPP-A. Furthermore, circulating PAPP-A2 was immunoaffinity purified and characterized by sequence analysis and mass spectrometry. Unlike PAPP-A, PAPP-A2 is a noncovalent dimer in which each subunit of 1558 amino acids originates from all of the 22 predicted coding exons. A previously hypothesized variant (PAPP-E) does not exist, but low amounts of a C-terminally truncated PAPP-A2 variant was detected. A sensitive and robust ELISA for full-length PAPP-A2 was developed and used to establish normal ranges of PAPP-A2 through pregnancy. The functional sensitivity of this ELISA at 20% CV was 0.08 ng/ml, and the serum concentration of PAPP-A2 was found to increase during pregnancy in agreement with placental synthesis. The existence of this assay will enable an assessment of the biomarker potential of PAPP-A2 in pre-eclampsia as well as other clinical conditions.
Collapse
Affiliation(s)
- S Kløverpris
- Department of Molecular Biology and Genetics, Aarhus University, Gustav Wieds Vej 10C, Aarhus C DK-8000, Denmark
| | | | | | | | | | | | | | | | | |
Collapse
|
29
|
Gaidamauskas E, Gyrup C, Boldt HB, Schack VR, Overgaard MT, Laursen LS, Oxvig C. IGF dependent modulation of IGF binding protein (IGFBP) proteolysis by pregnancy-associated plasma protein-A (PAPP-A): multiple PAPP-A-IGFBP interaction sites. Biochim Biophys Acta Gen Subj 2013; 1830:2701-9. [PMID: 23671931 DOI: 10.1016/j.bbagen.2012.11.002] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
BACKGROUND Pregnancy-associated plasma protein-A (PAPP-A) is a local regulator of insulin-like growth factor (IGF) bioavailability in physiological systems, but many structural and functional aspects of the metzincin metalloproteinase remain to be elucidated. PAPP-A cleaves IGF binding protein (IGFBP)-4 and IGFBP-5. Cleavage of IGFBP-4, but not IGFBP-5, depends on the binding of IGF before proteolysis by PAPP-A can occur. The paralogue PAPP-A2 has two substrates among the six IGFBPs: IGFBP-3 and IGFBP-5. METHODS Sets of chimeric proteins between IGFBP-4 and -5, and IGFBP-3 and -5 were constructed to investigate the structural requirements for IGF modulation. At the proteinase level, we investigated the importance of individual acidic amino acids positioned in the proteolytic domain of PAPP-A for proteolytic activity against IGFBP-4 and -5. Interaction between PAPP-A and its substrates was analyzed by surface plasmon resonance. RESULTS AND CONCLUSION We provide data suggesting that the C-terminal domain of the IGFBPs is responsible for IGF-dependent modulation of access to the scissile bond. Loss or reduction of IGFBP proteolysis by PAPP-A was observed upon mutation of residues positioned in the unique 63-residue stretch separating the zinc and Met-turn motifs, and in the short sequence following the Met-turn methionine. A model of the proteolytic domain of PAPP-A suggests the presence of structural calcium ions in the C-terminal subdomain, implicated in IGFBP substrate interactions. GENERAL SIGNIFICANCE Detailed knowledge of interactions between PAPP-A and its substrates is required to understand the modulatory role of PAPP-A on IGF receptor stimulation.
Collapse
Affiliation(s)
- Ervinas Gaidamauskas
- Department of Molecular Biology and Genetics, University of Aarhus, DK-8000 Aarhus, Denmark
| | | | | | | | | | | | | |
Collapse
|
30
|
Kjaer-Sorensen K, Engholm DH, Kamei H, Morch MG, Kristensen AO, Zhou J, Conover CA, Duan C, Oxvig C. Pregnancy-associated plasma protein A (PAPP-A) modulates the early developmental rate in zebrafish independently of its proteolytic activity. J Biol Chem 2013; 288:9982-9992. [PMID: 23430244 DOI: 10.1074/jbc.m112.426304] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
Pregnancy-associated plasma protein-A (PAPP-A) is a large metalloproteinase specifically cleaving insulin-like growth factor (IGF) binding proteins, causing increased IGF bioavailability and, hence, local regulation of IGF receptor activation. We have identified two highly conserved zebrafish homologs of the human PAPP-A gene. Expression of zebrafish Papp-a, one of the two paralogs, begins during gastrulation and persists throughout the first week of development, and analyses demonstrate highly conserved patterns of expression between adult zebrafish, humans, and mice. We show that the specific knockdown of zebrafish papp-a limits the developmental rate beginning during gastrulation without affecting the normal patterning of the embryo. This phenotype is different from those resulting from deficiency of Igf receptor or ligand in zebrafish, suggesting a function of Papp-a outside of the Igf system. Biochemical analysis of recombinant zebrafish Papp-a demonstrates conservation of proteolytic activity, specificity, and the intrinsic regulatory mechanism. However, in vitro transcribed mRNA, which encodes a proteolytically inactive Papp-a mutant, recues the papp-a knockdown phenotype as efficiently as wild-type Papp-a. Thus, the developmental phenotype of papp-a knockdown is not a consequence of lacking Papp-a proteolytic activity. We conclude that Papp-a possesses biological functions independent of its proteolytic activity. Our data represent the first evidence for a non-proteolytic function of PAPP-A.
Collapse
Affiliation(s)
- Kasper Kjaer-Sorensen
- Department of Molecular Biology and Genetics, Aarhus University, Gustav Wieds Vej 10C, 8000 Aarhus C, Denmark
| | - Ditte H Engholm
- Department of Molecular Biology and Genetics, Aarhus University, Gustav Wieds Vej 10C, 8000 Aarhus C, Denmark
| | - Hiroyasu Kamei
- Department of Molecular, Cellular, and Developmental Biology, University of Michigan, Ann Arbor, Michigan 48105
| | - Maria G Morch
- Department of Molecular Biology and Genetics, Aarhus University, Gustav Wieds Vej 10C, 8000 Aarhus C, Denmark
| | - Anisette O Kristensen
- Department of Molecular Biology and Genetics, Aarhus University, Gustav Wieds Vej 10C, 8000 Aarhus C, Denmark
| | - Jianfeng Zhou
- Department of Molecular, Cellular, and Developmental Biology, University of Michigan, Ann Arbor, Michigan 48105
| | - Cheryl A Conover
- Endocrine Research Unit, Mayo Clinic, Rochester, Minnesota 55905
| | - Cunming Duan
- Department of Molecular, Cellular, and Developmental Biology, University of Michigan, Ann Arbor, Michigan 48105
| | - Claus Oxvig
- Department of Molecular Biology and Genetics, Aarhus University, Gustav Wieds Vej 10C, 8000 Aarhus C, Denmark.
| |
Collapse
|
31
|
Protein secretion is required for pregnancy-associated plasma protein-A to promote lung cancer growth in vivo. PLoS One 2012; 7:e48799. [PMID: 23152806 PMCID: PMC3494721 DOI: 10.1371/journal.pone.0048799] [Citation(s) in RCA: 33] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/11/2012] [Accepted: 10/01/2012] [Indexed: 12/15/2022] Open
Abstract
Pregnancy-associated plasma protein-A (PAPPA) has been reported to regulate the activity of insulin-like growth factor (IGF) signal pathway through proteolytic degradation of IGF binding proteins (IGFBPs) thereby increasing the local concentration of free IGFs available to receptors. In this study we found that PAPPA is secreted from two out of seven lung cancer cell lines examined. None of immortalized normal bronchial epithelial cells (HBE) tested secrets PAPPA. There is no correlation between expression level and secretion of PAPPA in these cells. A cell line over-expressing PAPPA accompanied with secretion shows no notable changes in proliferation under cell culture conditions in vitro, but displays significantly augmentation of tumor growth in vivo in a xenograft model. In contrast, a cell line over-expressing PAPPA without secretion exhibits reduction of tumor growth both in vitro and in vivo. Down-regulation of PAPPA expression and secretion by RNAi knockdown decreases tumor growth after implanted in vivo. The tumor promoting activity of PAPPA appears to be mediated mainly through augmentation of the IGF signaling pathway as indicated by notable increases in downstream Akt kinase phosphorylation in tumor samples. Our results indicate that PAPPA secretion may play an important role in lung cancer growth and progression.
Collapse
|
32
|
Rich RL, Myszka DG. Grading the commercial optical biosensor literature-Class of 2008: 'The Mighty Binders'. J Mol Recognit 2010; 23:1-64. [PMID: 20017116 DOI: 10.1002/jmr.1004] [Citation(s) in RCA: 109] [Impact Index Per Article: 7.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022]
Abstract
Optical biosensor technology continues to be the method of choice for label-free, real-time interaction analysis. But when it comes to improving the quality of the biosensor literature, education should be fundamental. Of the 1413 articles published in 2008, less than 30% would pass the requirements for high-school chemistry. To teach by example, we spotlight 10 papers that illustrate how to implement the technology properly. Then we grade every paper published in 2008 on a scale from A to F and outline what features make a biosensor article fabulous, middling or abysmal. To help improve the quality of published data, we focus on a few experimental, analysis and presentation mistakes that are alarmingly common. With the literature as a guide, we want to ensure that no user is left behind.
Collapse
Affiliation(s)
- Rebecca L Rich
- Center for Biomolecular Interaction Analysis, University of Utah, Salt Lake City, UT 84132, USA
| | | |
Collapse
|
33
|
A single-domain llama antibody potently inhibits the enzymatic activity of botulinum neurotoxin by binding to the non-catalytic alpha-exosite binding region. J Mol Biol 2010; 397:1106-18. [PMID: 20138889 DOI: 10.1016/j.jmb.2010.01.070] [Citation(s) in RCA: 67] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/11/2009] [Accepted: 01/27/2010] [Indexed: 02/07/2023]
Abstract
Ingestion or inhalation of botulinum neurotoxin (BoNT) results in botulism, a severe and frequently fatal disease. Current treatments rely on antitoxins, which, while effective, cannot reverse symptoms once BoNT has entered the neuron. For treatments that can reverse intoxication, interest has focused on developing inhibitors of the enzymatic BoNT light chain (BoNT Lc). Such inhibitors typically mimic substrate and bind in or around the substrate cleavage pocket. To explore the full range of binding sites for serotype A light chain (BoNT/A Lc) inhibitors, we created a library of non-immune llama single-domain VHH (camelid heavy-chain variable region derived from heavy-chain-only antibody) antibodies displayed on the surface of the yeast Saccharomyces cerevisiae. Library selection on BoNT/A Lc yielded 15 yeast-displayed VHH with equilibrium dissociation constants (K(d)) from 230 to 0.03 nM measured by flow cytometry. Eight of 15 VHH inhibited the cleavage of substrate SNAP25 (synaptosome-associated protein of 25,000 Da) by BoNT/A Lc. The most potent VHH (Aa1) had a solution K(d) for BoNT/A Lc of 1.47 x 10(-)(10) M and an IC(50) (50% inhibitory concentration) of 4.7 x 10(-)(10) M and was resistant to heat denaturation and reducing conditions. To understand the mechanism by which Aa1 inhibited catalysis, we solved the X-ray crystal structure of the BoNT/A Lc-Aa1 VHH complex at 2.6 A resolution. The structure reveals that the Aa1 VHH binds in the alpha-exosite of the BoNT/A Lc, far from the active site for catalysis. The study validates the utility of non-immune llama VHH libraries as a source of enzyme inhibitors and identifies the BoNT/A Lc alpha-exosite as a target for inhibitor development.
Collapse
|
34
|
Effects of Insufficient Levels of Dietary Protein on IGF-I and IGFBPs in Young Chickens. J Poult Sci 2010. [DOI: 10.2141/jpsa.010031] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022] Open
|
35
|
Pires-Alves M, Ho M, Aberle KK, Janda KD, Wilson BA. Tandem fluorescent proteins as enhanced FRET-based substrates for botulinum neurotoxin activity. Toxicon 2009; 53:392-9. [PMID: 19168088 DOI: 10.1016/j.toxicon.2008.12.016] [Citation(s) in RCA: 27] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/10/2008] [Revised: 12/18/2008] [Accepted: 12/23/2008] [Indexed: 01/25/2023]
Abstract
The light chain of botulinum neurotoxin A (BoNT/A-LC) is a zinc-metalloprotease that requires two extended exosites for optimal substrate binding and recognition of its intracellular target SNAP25. CFP and YFP connected through SNAP25 peptide (141-206) containing both exosites (CsY) has been used in a FRET-based assay for BoNT/A. To further improve the FRET efficiency in this BoNT/A substrate for in vitro high-throughput assays, we explored the feasibility of enhancing the capture of CFP emission by doubling the number of YFP acceptors. In comparison to CsY, the tandem fluorescence substrates CsYY and YsCsY enhanced the ratiometric fluorescence signal between YFP and CFP. YsCsY, containing two substrate sites, offered the greatest fluorometric change upon toxin-catalyzed cleavage. In addition to known approaches for enhancing fluorescence yield through various mutations, this alternative tandem substrate approach can boost the FRET signal and is particularly useful for substrates requiring extensive exosite recognition for specificity.
Collapse
Affiliation(s)
- Melissa Pires-Alves
- Department of Microbiology, University of Illinois at Urbana-Champaign, Urbana, IL 61801, USA
| | | | | | | | | |
Collapse
|
36
|
Hayashi I, Takatori S, Urano Y, Iwanari H, Isoo N, Osawa S, Fukuda MA, Kodama T, Hamakubo T, Li T, Wong PC, Tomita T, Iwatsubo T. Single chain variable fragment against nicastrin inhibits the gamma-secretase activity. J Biol Chem 2009; 284:27838-27847. [PMID: 19684016 DOI: 10.1074/jbc.m109.055061] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
Gamma-secretase is a membrane protein complex that catalyzes intramembrane proteolysis of a variety of substrates including the amyloid beta precursor protein of Alzheimer disease. Nicastrin (NCT), a single-pass membrane glycoprotein that harbors a large extracellular domain, is an essential component of the gamma-secretase complex. Here we report that overexpression of a single chain variable fragment (scFv) against NCT as an intrabody suppressed the gamma-secretase activity. Biochemical analyses revealed that the scFv disrupted the proper folding and the appropriate glycosyl maturation of the endogenous NCT, which are required for the stability of the gamma-secretase complex and the intrinsic proteolytic activity, respectively, implicating the dual role of NCT in the gamma-secretase complex. Our results also highlight the importance of the calnexin cycle in the functional maturation of the gamma-secretase complex. The engineered intrabodies may serve as rationally designed, molecular targeting tools for the discovery of novel actions of the membrane proteins.
Collapse
Affiliation(s)
- Ikuo Hayashi
- Department of Neuropathology and Neuroscience, Graduate School of Pharmaceutical Sciences, The University of Tokyo, 7-3-1 Hongo, Bunkyo-ku, Tokyo 113-0033, Japan
| | - Sho Takatori
- Department of Neuropathology and Neuroscience, Graduate School of Pharmaceutical Sciences, The University of Tokyo, 7-3-1 Hongo, Bunkyo-ku, Tokyo 113-0033, Japan
| | - Yasuomi Urano
- Laboratory for Systems Biology and Medicine, Research Center for Advanced Science and Technology, The University of Tokyo, 4-6-1 Komaba, Meguro-ku, Tokyo 153-8904, Japan
| | - Hiroko Iwanari
- Laboratory for Systems Biology and Medicine, Research Center for Advanced Science and Technology, The University of Tokyo, 4-6-1 Komaba, Meguro-ku, Tokyo 153-8904, Japan; Perseus Proteomics, Inc., 4-7-6 Komaba, Meguro-ku, Tokyo 153-0041, Japan
| | - Noriko Isoo
- Department of Neuropathology and Neuroscience, Graduate School of Pharmaceutical Sciences, The University of Tokyo, 7-3-1 Hongo, Bunkyo-ku, Tokyo 113-0033, Japan
| | - Satoko Osawa
- Department of Neuropathology and Neuroscience, Graduate School of Pharmaceutical Sciences, The University of Tokyo, 7-3-1 Hongo, Bunkyo-ku, Tokyo 113-0033, Japan
| | - Maiko A Fukuda
- Department of Neuropathology and Neuroscience, Graduate School of Pharmaceutical Sciences, The University of Tokyo, 7-3-1 Hongo, Bunkyo-ku, Tokyo 113-0033, Japan
| | - Tatsuhiko Kodama
- Laboratory for Systems Biology and Medicine, Research Center for Advanced Science and Technology, The University of Tokyo, 4-6-1 Komaba, Meguro-ku, Tokyo 153-8904, Japan
| | - Takao Hamakubo
- Laboratory for Systems Biology and Medicine, Research Center for Advanced Science and Technology, The University of Tokyo, 4-6-1 Komaba, Meguro-ku, Tokyo 153-8904, Japan
| | - Tong Li
- Department of Pathology, The Johns Hopkins University School of Medicine, Baltimore, Maryland 21205
| | - Philip C Wong
- Department of Pathology, The Johns Hopkins University School of Medicine, Baltimore, Maryland 21205
| | - Taisuke Tomita
- Department of Neuropathology and Neuroscience, Graduate School of Pharmaceutical Sciences, The University of Tokyo, 7-3-1 Hongo, Bunkyo-ku, Tokyo 113-0033, Japan; Core Research for Evolutional Science and Technology, Japan Science and Technology Corporation, Graduate School of Medicine, The University of Tokyo, 7-3-1 Hongo, Bunkyo-ku, Tokyo 113-0033, Japan.
| | - Takeshi Iwatsubo
- Department of Neuropathology and Neuroscience, Graduate School of Pharmaceutical Sciences, The University of Tokyo, 7-3-1 Hongo, Bunkyo-ku, Tokyo 113-0033, Japan; Core Research for Evolutional Science and Technology, Japan Science and Technology Corporation, Graduate School of Medicine, The University of Tokyo, 7-3-1 Hongo, Bunkyo-ku, Tokyo 113-0033, Japan; Department of Neuropathology, Graduate School of Medicine, The University of Tokyo, 7-3-1 Hongo, Bunkyo-ku, Tokyo 113-0033, Japan
| |
Collapse
|