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Waugh CM, Scott A. Case Studies in Physiology: Adaptation of Loading-Bearing Tendons during Pregnancy. J Appl Physiol (1985) 2022; 132:1280-1289. [PMID: 35271408 DOI: 10.1152/japplphysiol.00555.2021] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
Pregnancy is characterized by hormone changes that could alter musculoskeletal (MSK) properties and temporarily increase soft tissue injury risk. Whilst the prevalence of MSK injuries in pregnancy has not yet proven itself to be a widespread problem, indirect evidence indicates an uptake in the prevalence of strength training and vigorous-intensity activity during pregnancy, which may result in increased MSK injury incidence. Combining this evidence with the association between sex hormones and MSK injury risk, we recognize the potential importance of this research area and believe the (prospective) examination of connective tissue properties in relation to hormonal changes in pregnancy are appropriate. Given the dearth of information on MSK adaptations to pregnancy, we present a variety of morphological, mechanical and functional tendon data from two consecutive pregnancies in one woman as a means of highlighting this under-researched topic. This data may be representative of the general pregnant population, or it may be highly individualized - more research is required for a better understanding of MSK adaptation and injury risk during and after pregnancy.
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Affiliation(s)
- Charlie M Waugh
- Department of Physical Therapy, Faculty of Medicine, University of British Columbia, Vancouver, BC, Canada
| | - Alexander Scott
- Department of Physical Therapy, Faculty of Medicine, University of British Columbia, Vancouver, BC, Canada
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2
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Ezhilarasan D. Relaxin in hepatic fibrosis: What is known and where to head? Biochimie 2021; 187:144-151. [PMID: 34102254 DOI: 10.1016/j.biochi.2021.06.001] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/03/2021] [Revised: 05/28/2021] [Accepted: 06/01/2021] [Indexed: 02/07/2023]
Abstract
Relaxin (RLX) is a heterodimeric, polypeptide hormone that has natural anti-fibrotic activity in many organs. During the chronic liver injury, hepatic stellate cells (HSCs) are phenotypically transformed into myofibroblasts. This process is known as activation of HSCs. Activated HSCs play a central role in hepatic fibrosis. Quiescent HSCs were shown to express low levels of RLX receptors such as RXFP1 and RXFP2. Upon chronic liver injury, HSCs are activated and express high levels of the RLX receptors. ML290, an agonist of RXFP1 has been reported to have antifibrotic effect in vitro as well as in vivo. Serelaxin, a recombinant human RLX-2 treatment has reduced hepatic fibrosis and portal hypertension in experimental models due to its vasodilation properties by inducing intrahepatic nitric oxide level. Serelaxin has also produced a neutral effect when studied against human cirrhosis-related portal hypertension in clinical trials. RLX is a potent collagen synthesis inhibitor and it has extracellular matrix (ECM) remodeling properties by promoting matrix metalloproteinases and downregulating expression of metalloproteinases inhibitors. Available reports suggest that RLX could induce ECM remodeling and suppress the profibrogenic transforming growth factor-β signaling and thereby regress hepatic fibrosis. Though RLX has natural antifibrotic activity, its antifibrotic molecular mechanisms especially in hepatic fibrosis condition are not reported. This review exclusively focuses antifibrotic effect of RLX on hepatic fibrosis.
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Affiliation(s)
- Devaraj Ezhilarasan
- Department of Pharmacology, The Blue Lab, Molecular Pharmacology and Toxicology Division, Saveetha Dental College, Saveetha Institute of Medical and Technical Sciences (SIMATS), Chennai, Tamil Nadu, 600 077, India.
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3
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Ivell R, Alhujaili W, Kohsaka T, Anand-Ivell R. Physiology and evolution of the INSL3/RXFP2 hormone/receptor system in higher vertebrates. Gen Comp Endocrinol 2020; 299:113583. [PMID: 32800774 DOI: 10.1016/j.ygcen.2020.113583] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/23/2020] [Accepted: 08/08/2020] [Indexed: 12/12/2022]
Abstract
Although the insulin-like peptide hormone INSL3 and its cognate receptor RXFP2 (relaxin-family peptide receptor 2) have existed throughout chordate evolution, their physiological diversification appears to be linked closely with mammalian emergence and radiation. In contrast, they have been lost in birds and reptiles. Both hormone and receptor are expressed from autosomal genes which have maintained their synteny across vertebrate evolution. Whereas the INSL3 gene comprises only two exons closely linked to the JAK3 gene, RXFP2 is normally encoded by 18 exons. Both genes, however, are subject to alternative splicing to yield a variety of possibly inactive or antagonistic molecules. In mammals, the INSL3-RXFP2 dyad has maintained a probably primitive association with gametogenesis, seen also in fish, whereby INSL3 promotes the survival, growth and differentiation of male germ cells in the testis and follicle development in the ovary. In addition, however, the INSL3/RXFP2 system has adopted a typical 'neohormone' profile, essential for the promotion of internal fertilisation and viviparity; fetal INSL3 is essential for the first phase of testicular descent into a scrotum, and also appears to be associated with male phenotype, in particular horn and skeletal growth. Circulating INSL3 is produced exclusively by the mature testicular Leydig cells in male mammals and acts as a potent biomarker for testis development during fetal and pubertal development as well as in ageing. As such it can be used also to monitor seasonally breeding animals as well as to investigate environmental or lifestyle conditions affecting development. Nevertheless, most information about INSL3 and RXFP2 comes from a very limited selection of species; it will be especially useful to gain further information from a more diverse range of animals, especially those whose evolution has led them to express unusual reproductive phenotypes.
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Affiliation(s)
- Richard Ivell
- School of Bioscience, University of Nottingham, Sutton Bonington, LE2 5RD, UK; School of Veterinary Medicine and Science, University of Nottingham, Sutton Bonington, LE2 5RD, UK.
| | - Waleed Alhujaili
- School of Bioscience, University of Nottingham, Sutton Bonington, LE2 5RD, UK
| | - Tetsuya Kohsaka
- Dept. of Applied Life Science, Shizuoka University, 836 Ohya, Suruga-ku, Shizuoka, Japan
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Chen TY, Li X, Hung CH, Bahudhanapati H, Tan J, Kass DJ, Zhang Y. The relaxin family peptide receptor 1 (RXFP1): An emerging player in human health and disease. Mol Genet Genomic Med 2020; 8:e1194. [PMID: 32100955 PMCID: PMC7196478 DOI: 10.1002/mgg3.1194] [Citation(s) in RCA: 14] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/15/2020] [Accepted: 02/11/2020] [Indexed: 12/14/2022] Open
Abstract
Background Relaxin/relaxin family peptide receptor 1 (RXFP1) signaling is important for both normal physiology and disease. Strong preclinical evidence supports relaxin as a potent antifibrotic molecule. However, relaxin‐based therapy failed in clinical trial in patients with systemic sclerosis. We and others have discovered that aberrant expression of RXFP1 may contribute to the abnormal relaxin/RXFP1 signaling in different diseases. Reduced RXFP1 expression and alternative splicing transcripts with potential functional consequences have been observed in fibrotic tissues. A relative decrease in RXFP1 expression in fibrotic tissues—specifically lung and skin—may explain a potential insensitivity to relaxin. In addition, receptor dimerization also plays important roles in relaxin/RXFP1 signaling. Methods This review describes the tissue specific expression, characteristics of the splicing variants, and homo/heterodimerization of RXFP1 in both normal physiological function and human diseases. We discuss the potential implications of these molecular features for developing therapeutics to restore relaxin/RXFP1 signaling and to harness relaxin's potential antifibrotic effects. Results Relaxin/RXFP1 signaling is important in both normal physiology and in human diseases. Reduced expression of RXFP1 in fibrotic lung and skin tissues surrenders both relaxin/RXFP1 signaling and their responsiveness to exogenous relaxin treatments. Alternative splicing and receptor dimerization are also important in regulating relaxin/RXFP1 signaling. Conclusions Understanding the molecular mechanisms that drive aberrant expression of RXFP1 in disease and the functional roles of alternative splicing and receptor dimerization will provide insight into therapeutic targets that may restore the relaxin responsiveness of fibrotic tissues.
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Affiliation(s)
- Ting-Yun Chen
- Division of Pulmonary, Allergy and Critical Care Medicine and the Dorothy P. and Richard P. Simmons Center for Interstitial Lung Disease, University of Pittsburgh, Pittsburgh, PA, USA.,Institute of Allied Health Sciences, National Cheng Kung University, Tainan, Taiwan
| | - Xiaoyun Li
- Division of Pulmonary, Allergy and Critical Care Medicine and the Dorothy P. and Richard P. Simmons Center for Interstitial Lung Disease, University of Pittsburgh, Pittsburgh, PA, USA
| | - Ching-Hsia Hung
- Institute of Allied Health Sciences, National Cheng Kung University, Tainan, Taiwan
| | - Harinath Bahudhanapati
- Division of Pulmonary, Allergy and Critical Care Medicine and the Dorothy P. and Richard P. Simmons Center for Interstitial Lung Disease, University of Pittsburgh, Pittsburgh, PA, USA
| | - Jiangning Tan
- Division of Pulmonary, Allergy and Critical Care Medicine and the Dorothy P. and Richard P. Simmons Center for Interstitial Lung Disease, University of Pittsburgh, Pittsburgh, PA, USA
| | - Daniel J Kass
- Division of Pulmonary, Allergy and Critical Care Medicine and the Dorothy P. and Richard P. Simmons Center for Interstitial Lung Disease, University of Pittsburgh, Pittsburgh, PA, USA
| | - Yingze Zhang
- Division of Pulmonary, Allergy and Critical Care Medicine and the Dorothy P. and Richard P. Simmons Center for Interstitial Lung Disease, University of Pittsburgh, Pittsburgh, PA, USA.,Department of Human Genetics, University of Pittsburgh, Pittsburgh, PA, USA
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5
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Ivell R, Anand-Ivell R. Insulin-like peptide 3 (INSL3) is a major regulator of female reproductive physiology. Hum Reprod Update 2018; 24:639-651. [DOI: 10.1093/humupd/dmy029] [Citation(s) in RCA: 29] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/08/2018] [Accepted: 08/31/2018] [Indexed: 12/16/2022] Open
Affiliation(s)
- Richard Ivell
- School of Biosciences, University of Nottingham, Sutton Bonington, UK
- School of Veterinary Medicine and Science, University of Nottingham, Sutton Bonington, UK
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6
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Avilés-Vázquez S, Chávez-González A, Hidalgo-Miranda A, Moreno-Lorenzana D, Arriaga-Pizano L, Sandoval-Esquivel MÁ, Ayala-Sánchez M, Aguilar R, Alfaro-Ruiz L, Mayani H. Global gene expression profiles of hematopoietic stem and progenitor cells from patients with chronic myeloid leukemia: the effect of in vitro culture with or without imatinib. Cancer Med 2017; 6:2942-2956. [PMID: 29030909 PMCID: PMC5727298 DOI: 10.1002/cam4.1187] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/24/2017] [Revised: 08/11/2017] [Accepted: 08/14/2017] [Indexed: 01/04/2023] Open
Abstract
In this study, we determined the gene expression profiles of bone marrow‐derived cell fractions, obtained from normal subjects and Chronic Myeloid Leukemia (CML) patients, that were highly enriched for hematopoietic stem (HSCs) and progenitor (HPCs) cells. Our results indicate that the profiles of CML HSCs and HPCs were closer to that of normal progenitors, whereas normal HSCs showed the most different expression profile of all. We found that the expression profiles of HSCs and HPCs from CML marrow were closer to each other than those of HSCs and HPCs from normal marrow. The major biologic processes dysregulated in CML cells included DNA repair, cell cycle, chromosome condensation, cell adhesion, and the immune response. We also determined the genomic changes in both normal and CML progenitor cells under culture conditions, and found that several genes involved in cell cycle, steroid biosynthesis, and chromosome segregation were upregulated, whereas genes involved in transcription regulation and apoptosis were downregulated. Interestingly, these changes were the same, regardless of the addition of Imatinib (IM) to the culture. Finally, we identified three genes—PIEZO2, RXFP1, and MAMDC2‐ that are preferentially expressed by CML primitive cells and that encode for cell membrane proteins; thus, they could be used as biomarkers for CML stem cells.
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Affiliation(s)
- Sócrates Avilés-Vázquez
- Oncology Research Unit, Oncology Hospital, National Medical Center, Mexican Institute for Social Security, Mexico City, Mexico
| | - Antonieta Chávez-González
- Oncology Research Unit, Oncology Hospital, National Medical Center, Mexican Institute for Social Security, Mexico City, Mexico
| | | | - Dafne Moreno-Lorenzana
- Oncology Research Unit, Oncology Hospital, National Medical Center, Mexican Institute for Social Security, Mexico City, Mexico
| | - Lourdes Arriaga-Pizano
- Immunochemistry Research Unit, National Medical Center, Mexican Institute for Social Security, Mexico City, Mexico
| | - Miguel Á Sandoval-Esquivel
- Oncology Research Unit, Oncology Hospital, National Medical Center, Mexican Institute for Social Security, Mexico City, Mexico
| | - Manuel Ayala-Sánchez
- Department of Hematology, La Raza Medical Center, Mexican Institute for Social Security, Mexico City, Mexico
| | - Rafael Aguilar
- Department of Hip Surgery, Villa Coapa General Hospital, Mexican Institute for Social Security, Mexico City, Mexico
| | | | - Hector Mayani
- Oncology Research Unit, Oncology Hospital, National Medical Center, Mexican Institute for Social Security, Mexico City, Mexico
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Dai Y, Ivell R, Liu X, Janowski D, Anand-Ivell R. Relaxin-Family Peptide Receptors 1 and 2 Are Fully Functional in the Bovine. Front Physiol 2017. [PMID: 28634453 PMCID: PMC5459885 DOI: 10.3389/fphys.2017.00359] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/06/2023] Open
Abstract
In most mammals the peptide hormone relaxin is a key physiological component regulating early pregnancy and birth. However, synteny analysis shows that the gene encoding ovarian relaxin-2 is deleted in cows and sheep. While, these ruminants appear to exhibit a relaxin-like physiology, as in other mammals, until now a molecular understanding of this has been lacking. Cloning and expression analysis of the cognate bovine receptor for relaxin, RXFP1, as well as of the structurally related receptor, RXFP2, in female tissues, shows that these are expressed in a similar way to other mammals. RXFP1 transcripts are found in ovarian theca cells, endometrium, and myometrium, whereas RXFP2 transcripts are expressed in ovarian theca cells, oocytes, as well as in myometrium. Transfection of receptor-expressing gene constructs into HEK293 cells indicates that bovine RXFP1 has a greater EC50 at 10–50 nM for porcine or human relaxin, compared to human RXFP1. For bovine RXFP2, in contrast, the EC50 is <1 nM for its cognate ligand, bovine INSL3, but also 10–30 nM for porcine or human relaxin. Functional analysis shows that bovine myometrial cells are able to respond to exogenous relaxin and INSL3 with a significant increase in cAMP. Although expressing mRNA for both RXFP1 and RXFP2, bovine follicular theca cells only respond to INSL3 with a dose-dependent increase in cAMP. Altogether the results suggest that the cow is able to compensate for the missing hormone, and moreover imply that relaxin analogs could offer an important therapeutic option in treating female ruminant infertility.
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Affiliation(s)
- Yanzhenzi Dai
- School of Biosciences, University of NottinghamNottingham, United Kingdom.,Leibniz Institute for Farm Animal BiologyDummerstorf, Germany
| | - Richard Ivell
- School of Biosciences, University of NottinghamNottingham, United Kingdom.,Leibniz Institute for Farm Animal BiologyDummerstorf, Germany.,School of Biological Sciences, University of AdelaideAdelaide, SA, Australia
| | - Xuan Liu
- Leibniz Institute for Farm Animal BiologyDummerstorf, Germany
| | - Dana Janowski
- Leibniz Institute for Farm Animal BiologyDummerstorf, Germany
| | - Ravinder Anand-Ivell
- School of Biosciences, University of NottinghamNottingham, United Kingdom.,Leibniz Institute for Farm Animal BiologyDummerstorf, Germany
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8
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Rymen D, Jaeken J. Skin manifestations in CDG. J Inherit Metab Dis 2014; 37:699-708. [PMID: 24554337 DOI: 10.1007/s10545-014-9678-7] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/30/2013] [Revised: 12/01/2013] [Accepted: 01/20/2014] [Indexed: 10/25/2022]
Abstract
The group of congenital disorders of glycosylation (CDG) has expanded tremendously since its first description in 1980, with around 70 distinct disorders described to date. A great phenotypic variability exists, ranging from multisystem disease to single organ involvement. Skin manifestations, although inconsistently present, are part of this broad clinical spectrum. Indeed, the presence of inverted nipples, fat pads and orange peel skin in a patient with developmental delay are considered as a hallmark of CDG, particularly seen in PMM2 deficiency. However, over the years many more dermatological findings have been observed (e.g., ichthyosis, cutis laxa, tumoral calcinosis…). In this review we will discuss the variety of skin manifestations reported in CDG. Moreover, we will explore the possible mechanisms that link a certain glycosylation deficiency to its skin phenotype.
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Affiliation(s)
- D Rymen
- Center for Human Genetics, University of Leuven, Leuven, Belgium,
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Cernaro V, Lacquaniti A, Lupica R, Buemi A, Trimboli D, Giorgianni G, Bolignano D, Buemi M. Relaxin: new pathophysiological aspects and pharmacological perspectives for an old protein. Med Res Rev 2013; 34:77-105. [PMID: 23401142 DOI: 10.1002/med.21277] [Citation(s) in RCA: 42] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/16/2022]
Abstract
Human relaxin-2 (hereafter simply defined as "relaxin") is a 6-kDa peptidic hormone best known for the physiological role played during pregnancy in the growth and differentiation of the reproductive tract and in the renal and systemic hemodynamic changes. This factor can also be involved in the pathophysiology of arterial hypertension and heart failure, in the molecular pathways of fibrosis and cancer, and in angiogenesis and bone remodeling. It belongs to the relaxin peptide family, whose members comprehensively exert numerous effects through interaction with different types of receptors, classified as relaxin family peptide (RXFP) receptors (RXFP1, RXFP2, RXFP3, RXFP4). Research looks toward the in-depth examination and complete understanding of relaxin in its various pleiotropic actions. The intent is to evaluate the likelihood of employing this substance for therapeutic purposes, for instance in diseases where a deficit could be part of the underlying pathophysiological mechanisms, also avoiding any adverse effect. Relaxin is already being considered as a promising drug, especially in acute heart failure. A careful study of the different RXFPs and their receptors and the comprehension of all biological activities of these hormones will probably provide new drugs with a potential wide range of therapeutic applications in the near future.
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Affiliation(s)
- Valeria Cernaro
- Department of Internal Medicine, University of Messina, Via Consolare Valeria, 1, 98100, Italy
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Hayakawa EH, Furutani M, Matsuoka R, Takakuwa Y. Comparison of protein behavior between wild-type and G601S hERG in living cells by fluorescence correlation spectroscopy. J Physiol Sci 2011; 61:313-9. [PMID: 21573751 PMCID: PMC10717380 DOI: 10.1007/s12576-011-0150-2] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/06/2011] [Accepted: 04/17/2011] [Indexed: 11/24/2022]
Abstract
The human ether-a-go-go-related gene (hERG) protein is a cardiac potassium channel. Mutations in hERG can result in reductions in membrane channel current, cardiac repolarization, prolongation of QT intervals, and lethal arrhythmia. In the last decade, it has been found that some mutants of hERG involved in long QT syndrome exhibit intracellular protein trafficking defects, while other mutants sort to the membrane but cannot form functional channels. Due to the close relationship between intracellular trafficking and functional protein expression, we aimed to measure differences in protein behavior/motion between wild-type and mutant hERG by directly analyzing the fluorescence fluctuations of green fluorescent protein-labeled proteins using fluorescence correlation spectroscopy (FCS). Our data imply that FCS can be applied as a new diagnostic tool to assess whether the defect in a particular mutant channel protein involves aberrant intracellular trafficking.
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Affiliation(s)
- Eri H. Hayakawa
- International Research and Educational Institute for Integrated Medical Sciences (IREIIMS), Tokyo Women’s Medical University, 8-1 Kawata-cho, Shinjuku-ku, Tokyo, 162-8666 Japan
- Present Address: Laboratory of Medical Zoology and Parasitology, Department of Infection and Immunity, Jichi Medical University, 3311-1 Yakushiji, Shimotsuke, Tochigi 329-0498 Japan
| | - Michiko Furutani
- International Research and Educational Institute for Integrated Medical Sciences (IREIIMS), Tokyo Women’s Medical University, 8-1 Kawata-cho, Shinjuku-ku, Tokyo, 162-8666 Japan
- Department of Pediatric Cardiology, Tokyo Women’s Medical University, 8-1 Kawata-cho, Shinjuku-ku, Tokyo, 162-8666 Japan
| | - Rumiko Matsuoka
- International Research and Educational Institute for Integrated Medical Sciences (IREIIMS), Tokyo Women’s Medical University, 8-1 Kawata-cho, Shinjuku-ku, Tokyo, 162-8666 Japan
- Department of Pediatric Cardiology, Tokyo Women’s Medical University, 8-1 Kawata-cho, Shinjuku-ku, Tokyo, 162-8666 Japan
| | - Yuichi Takakuwa
- International Research and Educational Institute for Integrated Medical Sciences (IREIIMS), Tokyo Women’s Medical University, 8-1 Kawata-cho, Shinjuku-ku, Tokyo, 162-8666 Japan
- Department of Biochemistry, Tokyo Women’s Medical University, 8-1 Kawata-cho, Shinjuku-ku, Tokyo, 162-8666 Japan
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Pearson SJ, Burgess KE, Onambélé GL. Serum relaxin levels affect the in vivo properties of some but not all tendons in normally menstruating young women. Exp Physiol 2011. [DOI: 10.1113/exphysiol.2011.057877] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
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12
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Pearson SJ, Burgess KE, Onambélé GL. Serum relaxin levels affect the in vivo properties of some but not all tendons in normally menstruating young women. Exp Physiol 2011; 96:681-8. [PMID: 21478257 DOI: 10.1113/expphysiol.2011.057877] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
Abstract
Relaxin (hRLX) is a hormone reported to affect collagen synthesis. Its effects are also thought to be modulated by other sex hormones, including oestrogen, which has previously been found to be associated with alterations of in vivo tendon properties. There is thus a potential for hRLX to impact on collagen, which could result in tendon structural and mechanical properties being modified. The present study therefore aimed to determine any interaction between hRLX and tendon stiffness, in normally menstruating women (n = 12). Tendon properties were determined using a combination of dynamometry and B-mode ultrasound, whilst serum hRLX levels were established by ELISA. Serum hRLX level was seen to be negatively associated with patellar tendon stiffness (r = -0.56; P < 0.001), explaining 31% of the variance in this parameter. There was no association between hRLX and gastrocnemius tendon stiffness (P > 0.05), or with the cross-sectional area of either of the two tendons (P > 0.05). In young, normally menstruating women, hRLX appears to have a significant effect on the patellar but not the gastrocnemius tendon stiffness. Where it has an effect, this appears to be on the intrinsic properties rather than on the dimensions of said tendon. Future work to elucidate the physiological cause of this selectivity in the impact of relaxin will be key to mapping the impact of the endocrine system on the phenotype of tendinous tissue.
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Affiliation(s)
- S J Pearson
- School of Health, Sport and Rehabilitation Sciences, Exercise and Physiotherapy, University of Salford, Manchester, UK.
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13
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Abstract
Relaxin is an approximately 6-kilodalton peptide hormone secreted by the corpus luteum, and circulates in the maternal blood during pregnancy. Relaxin administration to awake, chronically instrumented, nonpregnant rats mimics the vasodilatory phenomena of pregnancy. Furthermore, immunoneutralization of relaxin or its elimination from the circulation during midterm pregnancy in awake rats prevents maternal systemic and renal vasodilation, and the increase in global arterial compliance. Human investigation, albeit limited through 2010, also reveals vasodilatory effects of relaxin in the nonpregnant condition and observations consistent with a role for relaxin in gestational renal hyperfiltration. Evidence suggests that the vasodilatory responses of relaxin are mediated by its major receptor, the relaxin/insulin-like family peptide 1 receptor, RFXP1. The molecular mechanisms of relaxin vasodilation depend on the duration of hormone exposure (ie, there are rapid and sustained vasodilatory responses). Newly emerging data support the role of Gα(i/o) protein coupling to phosphatidylinositol-3 kinase/Akt (protein kinase B)-dependent phosphorylation and activation of endothelial nitric oxide synthase in the rapid vasodilatory responses of relaxin. Sustained vasodilatory responses critically depend on vascular endothelial and placental growth factors, and increases in arterial gelatinase(s) activity. Gelatinases hydrolyze big endothelin (ET) at a gly-leu bond to form ET(1-32), which activates the endothelial ET(B)/nitric oxide vasodilatory pathway. Although the relevance of relaxin biology to preeclampsia is largely speculative at this time, there are potential tantalizing links that are discussed in the context of our current understanding of the etiology and pathophysiology of the disease.
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Affiliation(s)
- Kirk P Conrad
- Department of Physiology and Functional Genomics, University of Florida College of Medicine, 1600 SW Archer Road, Gainesville, FL 32610, USA.
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14
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Jaeger S, Ertaylan G, van Dijk D, Leser U, Sloot P. Inference of surface membrane factors of HIV-1 infection through functional interaction networks. PLoS One 2010; 5:e13139. [PMID: 20967291 PMCID: PMC2953485 DOI: 10.1371/journal.pone.0013139] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/11/2010] [Accepted: 09/08/2010] [Indexed: 01/26/2023] Open
Abstract
BACKGROUND HIV infection affects the populations of T helper cells, dendritic cells and macrophages. Moreover, it has a serious impact on the central nervous system. It is yet not clear whether this list is complete and why specifically those cell types are affected. To address this question, we have developed a method to identify cellular surface proteins that permit, mediate or enhance HIV infection in different cell/tissue types in HIV-infected individuals. Receptors associated with HIV infection share common functions and domains and are involved in similar cellular processes. These properties are exploited by bioinformatics techniques to predict novel cell surface proteins that potentially interact with HIV. METHODOLOGY/PRINCIPAL FINDINGS We compiled a set of surface membrane proteins (SMP) that are known to interact with HIV. This set is extended by proteins that have direct interaction and share functional similarity. This resulted in a comprehensive network around the initial SMP set. Using network centrality analysis we predict novel surface membrane factors from the annotated network. We identify 21 surface membrane factors, among which three have confirmed functions in HIV infection, seven have been identified by at least two other studies, and eleven are novel predictions and thus excellent targets for experimental investigation. CONCLUSIONS Determining to what extent HIV can interact with human SMPs is an important step towards understanding patient specific disease progression. Using various bioinformatics techniques, we generate a set of surface membrane factors that constitutes a well-founded starting point for experimental testing of cell/tissue susceptibility of different HIV strains as well as for cohort studies evaluating patient specific disease progression.
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Affiliation(s)
- Samira Jaeger
- Knowledge Management in Bioinformatics, Humboldt-Universität Berlin, Berlin, Germany
- Algorithmic Computational Biology, Centrum Wiskunde and Informatica, Amsterdam, The Netherlands
| | - Gokhan Ertaylan
- Computational Science, University of Amsterdam, Amsterdam, The Netherlands
| | - David van Dijk
- Computational Science, University of Amsterdam, Amsterdam, The Netherlands
| | - Ulf Leser
- Knowledge Management in Bioinformatics, Humboldt-Universität Berlin, Berlin, Germany
| | - Peter Sloot
- Computational Science, University of Amsterdam, Amsterdam, The Netherlands
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