title: Effects of somatotrophic axis (GH/GHR) double transgenesis on structural and molecular aspects of the zebrafish immune system.
abstract: The development of growth hormone (GH) transgenic fish has been shown to be a promising method to improve growth rates. However, the role of GH is not restricted only to processes involved in growth. Several others physiological processes, including immune function, are impaired due to GH imbalances. Given the importance of generating GH transgenic organisms for aquaculture purposes, it is necessary to develop strategies to reduce or compensate for the collateral effects of GH. We hypothesized that the generation of double transgenic fish that overexpress GH and growth hormone receptor (GHR) in the skeletal muscle could be a possible alternative to compensate for the deleterious effects of GH on the immune system. Specifically, we hypothesized that increased GHR amounts in the skeletal muscle would be able to reduce the level of circulating GH, attenuating the GH signaling on the immune cells while still increasing the growth rate. To test this hypothesis, we evaluated the size of the immune organs, T cell content in the thymus and head kidney, and expression of immune-related genes in double-transgenic fish. Contrary to our expectations, we found that the overexpression of GHR does not decrease the deleterious effect of GH excess on the size of the thymus and head kidney, and in the content of CD3(+) and CD4(+) cells in the thymus and head kidney. Unexpectedly, the control GHR transgenic group showed similar impairments in immune system parameters. These results indicate that GHR overexpression does not reverse the impairments caused by GH and, in addition, could reinforce the damage to the immune functions in GH transgenic zebrafish.
authors.affiliation: Laboratório de Biologia Molecular, Instituto de Ciências Biológicas, Universidade Federal do Rio Grande - FURG, Brazil.
authors.forename: Carolina Reyes
authors.initials: CR
authors.lastname: Batista
authors.affiliation: Laboratório de Biologia Molecular, Instituto de Ciências Biológicas, Universidade Federal do Rio Grande - FURG, Brazil.
authors.forename: Marcio Azevedo
authors.initials: MA
authors.lastname: Figueiredo
authors.affiliation: Laboratório de Biologia Molecular, Instituto de Ciências Biológicas, Universidade Federal do Rio Grande - FURG, Brazil.
authors.forename: Daniela Volcan
authors.initials: DV
authors.lastname: Almeida
authors.affiliation: Laboratório de Imunologia e Patologia de Organismos Aquáticos, Estação Marinha de Aquicultura, Instituto de Oceanografia, Universidade Federal do Rio Grande - FURG, Brazil.
authors.forename: Luis Alberto
authors.initials: LA
authors.lastname: Romano
authors.affiliation: Laboratório de Biologia Molecular, Instituto de Ciências Biológicas, Universidade Federal do Rio Grande - FURG, Brazil. Electronic address: dqmluf@furg.br.
authors.forename: Luis Fernando
authors.initials: LF
authors.lastname: Marins
mesh_terms: D000818:Animals; D030801:Animals, Genetically Modified / Q000235:genetics / Q000276:immunology / Q000378:metabolism; D005260:Female; D015870:Gene Expression; D018014:Gene Transfer Techniques; D013006:Growth Hormone / Q000235:genetics / Q000276:immunology / Q000378:metabolism; D008297:Male; D018482:Muscle, Skeletal / Q000378:metabolism; D011986:Receptors, Somatotropin / Q000235:genetics / Q000276:immunology / Q000378:metabolism; D015027:Zebrafish / Q000235:genetics / Q000276:immunology / Q000378:metabolism; D029961:Zebrafish Proteins / Q000235:genetics / Q000276:immunology / Q000378:metabolism
chemical_list: D011986:Receptors, Somatotropin; D029961:Zebrafish Proteins; D013006:Growth Hormone
keywords: Gene expression; Growth hormone; Growth hormone receptor; Head kidney; Thymus