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Martines EV, Reggiani PC, Camihort G, Luna G, Zappa MF, Brown OA, Goya RG, Cónsole GM. The thymulin-lactotropic axis in rodents: thymectomy, immunoneutralization and gene transfer studies. Neuroimmunomodulation 2013; 20:256-63. [PMID: 23941809 DOI: 10.1159/000346477] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/12/2012] [Accepted: 12/12/2012] [Indexed: 11/19/2022] Open
Abstract
OBJECTIVES There is clear evidence on the existence of a thymus-pituitary axis which seems to be particularly important during perinatal life. In particular, the thymic peptide thymulin has been shown to be a relevant player in thymus-pituitary communication. Our goal was to explore the effect of thymulin on circulating prolactin (PRL) levels in different animal models. To this end we undertook a series of experiments in rats and mice, implementing adult thymectomy, thymulin immunoneutralization in normal C57BL/6 mice and neonatal thymulin gene therapy in nude mice. METHODS We assessed the impact of the above manipulations on PRL secretion and lactotrope morphology by measuring serum PRL by radioimmunoassay and by performing morphometric analysis of the lactotropic cell population in the anterior pituitary gland. RESULTS Adult thymectomy in female rats slightly increased serum PRL, an effect that was partially reversed by thymulin gene therapy. In mice, thymulin immunoneutralization from birth to age 32 days reduced serum PRL both in males and females. Thymulin immunoneutralization induced a significant (p < 0.01) decrease in lactotrope cell density (CD) and volume density (VD) without changes in cell size (CS). Neonatal thymulin gene therapy markedly increased serum thymulin (p < 0.01) and lactotrope CD, CS and VD in nude mice of both sexes. CONCLUSIONS Our findings suggest a modulatory effect of thymulin on the lactotrope cell population and on serum PRL, particularly during early life.
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Affiliation(s)
- Eliana V Martines
- Department of Cytology, Histology and Embryology B, Faculty of Medicine, University of La Plata, La Plata, Argentina
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Reggiani PC, Martines EV, Camihort GA, Poch B, Goya RG, Cónsole GM. Role of thymulin on the somatotropic axis in vivo. Life Sci 2012; 91:166-71. [PMID: 22781709 DOI: 10.1016/j.lfs.2012.06.037] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/23/2011] [Revised: 06/26/2012] [Accepted: 06/27/2012] [Indexed: 10/28/2022]
Abstract
AIMS There is clear evidence for the existence of a bi-directional thymus-somatotropic axis and several studies suggest that the thymic peptide thymulin may be involved in this communication. We undertook to assess the impact of serum thymulin immunoneutralization in C57BL/6 mice and that of neonatal thymulin gene therapy (NTGT) in nude mice on body weight (BW) gain and on the histomorphometric profile of the somatotrope population. MAIN METHODS Immunoneutralization of thymulin was done from postnatal day 1 to 35 by i.p. injections of rabbit anti-thymulin serum (α-FTS) and normal rabbit serum (NRS) in controls. NTGT was implemented in nudes using an adenoviral vector expressing a synthetic gene for thymulin (RAd-FTS). On postnatal day 1, heterozygous (nu/+) and homozygous (nu/nu) pups received a single bilateral i.m. injection either RAd-FTS or RAd-GFP (a control vector expressing green fluorescent protein). BW gain was recorded and at the end of the study the pituitaries were immunostained for growth hormone (GH). Serum GH and thymulin were determined by radioimmunoassay and bioassay, respectively. KEY FINDINGS Thymulin immunoneutralization induced a significant decrease in BW gain, serum GH and somatotrope cell density as well as an increase in somatotrope cell size. NTGT markedly increased BW gain, serum thymulin (P<0.01) and somatotrope cell and volume density in nu/nu mice. SIGNIFICANCE Our results suggest that thymulin plays a relevant physiological role on the thymus-somatotropic axis in mice.
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Affiliation(s)
- Paula C Reggiani
- Department of Cytology, Histology & Embryology B, Faculty of Medicine, University of La Plata, Argentina.
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Reggiani PC, Poch B, Cónsole GM, Rimoldi OJ, Schwerdt JI, Tüngler V, Garcia-Bravo MM, Dardenne M, Goya RG. Thymulin-based gene therapy and pituitary function in animal models of aging. Neuroimmunomodulation 2011; 18:350-6. [PMID: 21952687 PMCID: PMC3221262 DOI: 10.1159/000329495] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/19/2022] Open
Abstract
Thymulin is a thymic hormone exclusively produced by the thymic epithelial cells. After its discovery and initial characterization in the 1970s, it was demonstrated that thymulin production and secretion is strongly influenced by the neuroendocrine system. Conversely, a growing core of information, to be reviewed here, points to thymulin as a hypophysiotropic peptide. Additionally, thymulin was shown to possess anti-inflammatory and analgesic properties in the brain. In recent years, a synthetic DNA sequence coding for a biologically active analog of thymulin, metFTS, was constructed and cloned in different adenoviral vectors. These include bidirectional regulatable Tet-Off vector systems that simultaneously express metFTS and green fluorescent protein and that can be downregulated reversibly by the addition of the antibiotic doxycycline. A number of recent studies suggest that thymulin gene therapy may be a suitable therapeutic strategy to prevent some of the endocrine and reproductive alterations that typically appear in congenitally athymic (nude) mice, taken as a suitable model of neuroendocrine and reproductive aging. The present article briefly reviews the literature on the physiology of the thymulin-pituitary axis as well as on the new molecular tools available to exploit the therapeutic potential of thymulin.
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Affiliation(s)
- Paula C. Reggiani
- Institute for Biochemical Research, National University of La Plata (UNLP), La Plata, Argentina
- Histology B-CICPBA, Faculty of Medicine, National University of La Plata (UNLP), La Plata, Argentina
| | - Brenda Poch
- Institute for Biochemical Research, National University of La Plata (UNLP), La Plata, Argentina
- Histology B-CICPBA, Faculty of Medicine, National University of La Plata (UNLP), La Plata, Argentina
| | - Gloria M. Cónsole
- Histology B-CICPBA, Faculty of Medicine, National University of La Plata (UNLP), La Plata, Argentina
| | - Omar J. Rimoldi
- Institute for Biochemical Research, National University of La Plata (UNLP), La Plata, Argentina
| | - Jose I. Schwerdt
- Institute for Biochemical Research, National University of La Plata (UNLP), La Plata, Argentina
- Histology B-CICPBA, Faculty of Medicine, National University of La Plata (UNLP), La Plata, Argentina
| | - Victoria Tüngler
- Histology B-CICPBA, Faculty of Medicine, National University of La Plata (UNLP), La Plata, Argentina
- Institut für Pharmakologie und Toxikologie, Charité-Universitätsmedizin, Berlin, Germany
| | | | - Mireille Dardenne
- CNRS UMR 8147, Université Paris Descartes, Hôpital Necker, Paris, France
| | - Rodolfo G. Goya
- Institute for Biochemical Research, National University of La Plata (UNLP), La Plata, Argentina
- Histology B-CICPBA, Faculty of Medicine, National University of La Plata (UNLP), La Plata, Argentina
- *Rodolfo G. Goya, INIBIOLP, Faculty of Medicine, UNLP, CC 455, La Plata 1900 (Argentina), Tel. +54 221 425 6735, E-Mail
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