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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.
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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
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Adasheva DA, Lebedeva OS, Goliusova DV, Postnikov AB, Teriakova MV, Kopylova IV, Lagarkova MA, Katrukha AG, Serebryanaya DV. PAPP-A-Specific IGFBP-4 Proteolysis in Human Induced Pluripotent Stem Cell-Derived Cardiomyocytes. Int J Mol Sci 2023; 24:ijms24098420. [PMID: 37176126 PMCID: PMC10179360 DOI: 10.3390/ijms24098420] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/03/2023] [Revised: 05/03/2023] [Accepted: 05/04/2023] [Indexed: 05/15/2023] Open
Abstract
The insulin-like growth factors IGF-I and IGF-II-as well as their binding proteins (IGFBPs), which regulate their bioavailability-are involved in many pathological and physiological processes in cardiac tissue. Pregnancy-associated plasma protein A (PAPP-A) is a metalloprotease that preferentially cleaves IGFBP-4, releasing IGF and activating its biological activity. Previous studies have shown that PAPP-A-specific IGFBP-4 proteolysis is involved in the pathogenesis of cardiovascular diseases, such as ischemia, heart failure, and acute coronary syndrome. However, it remains unclear whether PAPP-A-specific IGFBP-4 proteolysis participates in human normal cardiomyocytes. Here, we report PAPP-A-specific IGFBP-4 proteolysis occurring in human cardiomyocytes derived from two independent induced pluripotent cell lines (hiPSC-CMs), detected both on the cell surface and in the cell secretome. PAPP-A was measured by fluoroimmune analysis (FIA) in a conditioned medium of hiPSC-CMs and was detected in concentrations of up to 4.3 ± 1.33 ng/mL and 3.8 ± 1.1 ng/mL. The level of PAPP-A-specific IGFBP-4 proteolysis was determined as the concentration of NT-IGFBP-4 proteolytic fragments using FIA for a proteolytic neo-epitope-specific assay. We showed that PAPP-A-specific IGFBP-4 proteolysis is IGF-dependent and inhibited by EDTA and 1,10-phenanthroline. Therefore, it may be concluded that PAPP-A-specific IGFBP-4 proteolysis functions in human normal cardiomyocytes, and hiPSC-CMs contain membrane-bound and secreted forms of proteolytically active PAPP-A.
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Affiliation(s)
- Daria A Adasheva
- Department of Biochemistry, Faculty of Biology, Lomonosov Moscow State University, 119991 Moscow, Russia
| | - Olga S Lebedeva
- Lopukhin Federal Research and Clinical Center of Physical-Chemical Medicine of Federal Medical Biological Agency, 119435 Moscow, Russia
| | - Daria V Goliusova
- Lopukhin Federal Research and Clinical Center of Physical-Chemical Medicine of Federal Medical Biological Agency, 119435 Moscow, Russia
| | | | - Maria V Teriakova
- Lopukhin Federal Research and Clinical Center of Physical-Chemical Medicine of Federal Medical Biological Agency, 119435 Moscow, Russia
| | - Irina V Kopylova
- Lopukhin Federal Research and Clinical Center of Physical-Chemical Medicine of Federal Medical Biological Agency, 119435 Moscow, Russia
| | - Maria A Lagarkova
- Lopukhin Federal Research and Clinical Center of Physical-Chemical Medicine of Federal Medical Biological Agency, 119435 Moscow, Russia
| | - Alexey G Katrukha
- Department of Biochemistry, Faculty of Biology, Lomonosov Moscow State University, 119991 Moscow, Russia
- Hytest Ltd., 20520 Turku, Finland
| | - Daria V Serebryanaya
- Department of Biochemistry, Faculty of Biology, Lomonosov Moscow State University, 119991 Moscow, Russia
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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.
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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
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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.
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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
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Serebryanaya DV, Adasheva DA, Konev AA, Artemieva MM, Katrukha IA, Postnikov AB, Medvedeva NA, Katrukha AG. IGFBP-4 Proteolysis by PAPP-A in a Primary Culture of Rat Neonatal Cardiomyocytes under Normal and Hypertrophic Conditions. BIOCHEMISTRY. BIOKHIMIIA 2021; 86:1395-1406. [PMID: 34906040 DOI: 10.1134/s0006297921110043] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/06/2021] [Revised: 09/03/2021] [Accepted: 09/03/2021] [Indexed: 06/14/2023]
Abstract
Cardiovascular diseases (CVD) are among the leading causes of death and disability worldwide. Pregnancy-associated plasma protein-A (PAPP-A) is a matrix metalloprotease localized on the cell surface. One of the substrates that PAPP-A cleaves is the insulin-like growth factor binding protein-4 (IGFBP-4), a member of the family of proteins that bind insulin-like growth factor (IGF). Proteolysis of IGFBP-4 by PAPP-A occurs at a specific site resulting in formation of two proteolytic fragments - N-terminal IGFBP-4 (NT-IGFBP-4) and C-terminal IGFBP-4 (CT-IGFBP-4), and leads to the release of IGF activating various cellular processes including migration, proliferation, and cell growth. Increased levels of the proteolytic IGFBP-4 fragments correlate with the development of CVD complications and increased risk of death in patients with the coronary heart disease, acute coronary syndrome, and heart failure. However, there is no direct evidence that PAPP-A specifically cleaves IGFBP-4 in the cardiac tissue under normal and pathological conditions. In the present study, using a primary culture of rat neonatal cardiomyocytes as a model, we have demonstrated that: 1) proteolysis of IGFBP-4 by PAPP-A occurs in the conditioned medium of cardiomyocytes, 2) PAPP-A-specific IGFBP-4 proteolysis is increased when cardiomyocytes are transformed to a hypertrophic state. Thus, it can be assumed that the enhancement of IGFBP-4 cleavage by PAPP-A and hypertrophic changes in cardiomyocytes accompanying CVD are interrelated, and PAPP-A appears to be one of the activators of the IGF-dependent processes in normal and hypertrophic-state cardiomyocytes.
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Affiliation(s)
- Daria V Serebryanaya
- Department of Biochemistry, Faculty of Biology, Lomonosov Moscow State University, Moscow, 119234, Russia.
| | - Daria A Adasheva
- Department of Biochemistry, Faculty of Biology, Lomonosov Moscow State University, Moscow, 119234, Russia
| | | | - Marina M Artemieva
- Department of Human and Animal Physiology, Faculty of Biology, Lomonosov Moscow State University, Moscow, 119234, Russia
| | - Ivan A Katrukha
- Department of Biochemistry, Faculty of Biology, Lomonosov Moscow State University, Moscow, 119234, Russia
- HyTest Ltd., Turku, 20520, Finland
| | - Alexander B Postnikov
- Department of Biochemistry, Faculty of Biology, Lomonosov Moscow State University, Moscow, 119234, Russia
- HyTest Ltd., Turku, 20520, Finland
| | - Natalia A Medvedeva
- Department of Human and Animal Physiology, Faculty of Biology, Lomonosov Moscow State University, Moscow, 119234, Russia
| | - Alexey G Katrukha
- Department of Biochemistry, Faculty of Biology, Lomonosov Moscow State University, Moscow, 119234, Russia
- HyTest Ltd., Turku, 20520, Finland
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Abstract
Insulin plays an important role during adipogenic differentiation of animal preadipocytes and the maintenance of mature phenotypes. However, its role and mechanism in dedifferentiation of adipocyte remains unclear. This study investigated the effects of insulin on dedifferentiation of mice adipocytes, and the potential mechanisms. The preadipocytes were isolated from the subcutaneous white adipose tissue of wild type (WT), TNFα gene mutant (TNFα-/-), leptin gene spontaneous point mutant (db/db) and TNFα-/-/db/db mice and were then induced for differentiation. Interestingly, dedifferentiation of these adipocytes occurred once removing exogenous insulin from the adipogenic medium. As characteristics of dedifferentiation of the adipocytes, downregulation of adipogenic markers, upregulation of stemness markers and loss of intracellular lipids were observed from the four genotypes. Notably, dedifferentiation was occurring earlier if the insulin signal was blocked. These dedifferentiated cells regained the potentials of the stem cell-like characteristics. There is no significant difference in the characteristics of the dedifferentiation between the adipocytes. Overall, the study provided evidence that insulin plays a negative regulatory role in the dedifferentiation of adipocytes. We also confirmed that both dedifferentiation of mouse adipocytes, and effect of the insulin on this process were independent of the cell genotypes, while it is a widespread phenomenon in the adipocytes.
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Affiliation(s)
- Liguo Zang
- Shandong Provincial Key Laboratory of Animal Resistant Biology, College of Life Sciences, Shandong Normal University, Jinan, China
| | - Suchart Kothan
- Center of Radiation Research and Medical Imaging, Department of Radiologic Technology, Faculty of Associated Medical Sciences, Chiang Mai University, Chiang Mai, Thailand
| | - Yiyi Yang
- Shandong Provincial Key Laboratory of Animal Resistant Biology, College of Life Sciences, Shandong Normal University, Jinan, China
| | - Xiangyi Zeng
- Shandong Provincial Key Laboratory of Animal Resistant Biology, College of Life Sciences, Shandong Normal University, Jinan, China
| | - Lingmin Ye
- Shandong Provincial Key Laboratory of Animal Resistant Biology, College of Life Sciences, Shandong Normal University, Jinan, China
| | - Jie Pan
- Shandong Provincial Key Laboratory of Animal Resistant Biology, College of Life Sciences, Shandong Normal University, Jinan, China
- Center of Radiation Research and Medical Imaging, Department of Radiologic Technology, Faculty of Associated Medical Sciences, Chiang Mai University, Chiang Mai, Thailand
- CONTACT Jie Pan College of Life Sciences, Shandong Normal University, 88 East Wenhua Ave. Jinan250014, China
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Liu B, Li Y, Du J, She Q, Deng S. Epicardial Adipose Tissue in Patients with Obstructive Sleep Apnea: A Systematic Review and Meta-analysis. CARDIOVASCULAR INNOVATIONS AND APPLICATIONS 2020. [DOI: 10.15212/cvia.2019.0594] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
Objective: Epicardial adipose tissue (EAT) is a potential risk factor for obstructive sleep apnea (OSA). We performed a meta-analysis to assess the association of EAT with OSA.Methods: The PubMed, EMBASE, Web of Science, Cochrane Library, and Wanfang databases were
searched by two independent investigators for all observational studies assessing the association of EAT with OSA. Then we assessed the association of EAT thickness (EAT-t) and EAT volume (EAT-v) with OSA by a meta-analysis.Results: Ten studies were included in the final analysis.
Compared with that in controls, EAT-t in OSA patients was significantly increased (standardized mean difference 0.88, 95% confidence interval 0.72‐1.05, P=0.000). Furthermore, EAT-t was greater in OSA patients than in controls with similar BMIs. However, we did not find significant
differences in EAT-v between OSA patients and controls (standardized mean difference 2.46, 95% confidence interval −0.36 to 5.29, P=0.088). EAT-t in the mild, moderate, and severe OSA subgroups was greater than in the controls. In addition, there were significant differences in EAT-t
among the mild, moderate, and severe OSA subgroups.Conclusions: EAT-t was greater in patients with OSA than in controls, and EAT-t was also associated with the severity of OSA. These findings may provide a new clue for the pathogenesis and treatment of OSA.
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Affiliation(s)
- Bin Liu
- Department of Cardiology, The Second Affiliated Hospital of Chongqing Medical University, Chongqing 400010, China
| | - Yingrui Li
- Department of Cardiology, The Second Affiliated Hospital of Chongqing Medical University, Chongqing 400010, China
| | - Jianlin Du
- Department of Cardiology, The Second Affiliated Hospital of Chongqing Medical University, Chongqing 400010, China
| | - Qiang She
- Department of Cardiology, The Second Affiliated Hospital of Chongqing Medical University, Chongqing 400010, China
| | - Songbai Deng
- Department of Cardiology, The Second Affiliated Hospital of Chongqing Medical University, Chongqing 400010, China
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Hjortebjerg R, Rasmussen LM, Gude MF, Irmukhamedov A, Riber LP, Frystyk J, De Mey JGR. Local IGF Bioactivity Associates with High PAPP-A Activity in the Pericardial Cavity of Cardiovascular Disease Patients. J Clin Endocrinol Metab 2020; 105:5900391. [PMID: 32875328 DOI: 10.1210/clinem/dgaa617] [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: 06/03/2020] [Accepted: 08/28/2020] [Indexed: 11/19/2022]
Abstract
OBJECTIVE Pregnancy-associated plasma protein-A (PAPP-A) has been suggested as a proatherogenic enzyme by its ability to locally increase insulin-like growth factor (IGF) activity through proteolytic cleavage of IGF binding protein-4 (IGFBP-4). Recently, stanniocalcin-2 (STC2) was discovered as an inhibitor of PAPP-A. This study aimed to investigate IGFBP-4, PAPP-A, and STC2 as local regulators of IGF bioactivity in the cardiac microenvironment by comparing levels in the pericardial fluid with those in the circulation of patients with cardiovascular disease. METHODS Plasma and pericardial fluid were obtained from 39 patients undergoing elective cardiothoracic surgery, hereof 15 patients with type 2 diabetes. Concentrations of IGF-I, intact and fragmented IGFBP-4, PAPP-A, and STC2 were determined by immunoassays and IGF bioactivity by a cell-based assay. RESULTS In pericardial fluid, the concentrations of total IGF-I, intact IGFBP-4, and STC2 were 72 ± 10%, 91 ± 5%, and 40 ± 24% lower than in plasma, while PAPP-A was 15 times more concentrated. The levels of the 2 IGFBP-4 fragments generated by PAPP-A and reflecting PAPP-A activity were elevated by more than 25%. IGF bioactivity was 62 ± 81% higher in the pericardial fluid than plasma. Moreover, pericardial fluid levels of both IGFBP-4 fragments correlated with the concentration of PAPP-A and with the bioactivity of IGF. All protein levels were similar in pericardial fluid from nondiabetic and diabetic subjects. CONCLUSIONS PAPP-A increases IGF bioactivity by cleavage of IGFBP-4 in the pericardial cavity of cardiovascular disease patients. This study provides evidence for a distinct local activity of the IGF system, which may promote cardiac dysfunction and coronary atherosclerosis.
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Affiliation(s)
- Rikke Hjortebjerg
- Department of Molecular Endocrinology (KMEB), University of Southern Denmark, Odense, Denmark
- Steno Diabetes Center Odense, Odense University Hospital, Odense, Denmark
- Medical Research Laboratory, Department of Clinical Medicine, Aarhus University, Denmark
| | - Lars Melholt Rasmussen
- Department of Clinical Biochemistry and Pharmacology, Odense University Hospital, Odense, Denmark
- Centre for Individualized Medicine in Arterial Diseases (CIMA), Odense University Hospital, Odense, Denmark
| | - Mette Faurholdt Gude
- Medical Research Laboratory, Department of Clinical Medicine, Aarhus University, Denmark
| | - Akhmadjon Irmukhamedov
- Department of Cardiac, Thoracic and Vascular Surgery, Odense University Hospital, Odense, Denmark
| | - Lars P Riber
- Department of Cardiac, Thoracic and Vascular Surgery, Odense University Hospital, Odense, Denmark
| | - Jan Frystyk
- Department of Molecular Endocrinology (KMEB), University of Southern Denmark, Odense, Denmark
- Department of Endocrinology, Odense University Hospital, Denmark
| | - Jo G R De Mey
- Centre for Individualized Medicine in Arterial Diseases (CIMA), Odense University Hospital, Odense, Denmark
- Department of Cardiac, Thoracic and Vascular Surgery, Odense University Hospital, Odense, Denmark
- Department of Cardiovascular and Renal Research, University of Southern Denmark, Odense, Denmark
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Ramakrishna A, Bale LK, West SA, Conover CA. Genetic and Pharmacological Inhibition of PAPP-A Protects Against Visceral Obesity in Mice. Endocrinology 2020; 161:5901798. [PMID: 32888014 PMCID: PMC7528556 DOI: 10.1210/endocr/bqaa160] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/10/2020] [Accepted: 09/01/2020] [Indexed: 01/29/2023]
Abstract
Pathogenicity of visceral adipose tissue (VAT) has been linked to the metabolic stress of enlarging mature adipocytes and a limited ability to recruit new adipocytes. One of the major distinguishing features of VAT preadipocytes is the high expression of the zinc metalloprotease, pregnancy-associated plasma protein-A (PAPP-A), when compared to subcutaneous adipose tissue (SAT). In this study we used 2 different approaches to investigate the effect of PAPP-A inhibition on different fat depots in mice on a high-fat diet (HFD) for 15 weeks. Conditional knockdown of PAPP-A gene expression in female adult mice resulted in significant decreases of 30% to 40% in adipocyte size in VAT (mesenteric and pericardial depots) compared to control mice. There was no effect on SAT (inguinal) or intra-abdominal perigonadal fat. Liver lipid was also significantly decreased without any effect on heart and skeletal muscle lipid. We found similar effects when using a pharmacological approach. Weekly injections of a specific immunoneutralizing monoclonal antibody (mAb-PA 1/41) or isotype control were given to male and female wild-type mice on HFD for 15 weeks. Adipocyte size was significantly decreased (30%-50%) only in VAT with mAb-PA 1/41 treatment. In this model, cell number was significantly increased in mesenteric fat in mice treated with mAb-PA 1/41, suggesting hyperplasia along with reduced hypertrophy in this VAT depot. Gene expression data indicated a significant decrease in F4/80 (macrophage marker) and interleukin-6 (proinflammatory cytokine) and a significant increase in adiponectin (anti-inflammatory adipokine with beneficial metabolic effects) in mesenteric fat compared to inguinal fat in mice treated with mAb-PA 1/41. Furthermore, there was significantly decreased liver lipid content with mAb-PA 1/41 treatment. Thus, using 2 different models systems we provide proof of principle that PAPP-A inhibition is a potential therapeutic target to prevent visceral obesity and its metabolic sequelae, such as fatty liver.
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Affiliation(s)
| | - Laurie K Bale
- Division of Endocrinology Mayo Clinic, Rochester, Minnesota
| | - Sally A West
- Division of Endocrinology Mayo Clinic, Rochester, Minnesota
| | - Cheryl A Conover
- Division of Endocrinology Mayo Clinic, Rochester, Minnesota
- Correspondence: Cheryl A. Conover, PhD, Mayo Clinic, Endocrine Research Unit, 200 First St SW, 5-194 Joseph, Rochester, MN 55905, USA. E-mail:
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