Sox2 Decreased Expression and Overexpression of Pituitary Hormone Codyfing Genes during Puberty in Model of Congenital Hypopituitarism Mice
Presentation Number: OR17-3
Date of Presentation: April 2nd, 2017
Juliana Moreira Silva*1, Claudia Veiga Chang2, Ricardo Viera Araujo3, Mariana F Guzzo4, Cinthya Santos Cirqueira5, Sally A Camper6, Berenice B Mendonca7 and Luciani R S Carvalho8
1Hospital das Clínicas of University of Sao Paulo, Medical School, São Paulo, Brazil, 2Hospital das Clinicas University of Sao Paulo, São Paulo, Brazil, 3University of Sao Paulo, Sao Paulo, Brazil, 4HC FMUSP, Sao Paulo, Brazil, 5University of Sao Paulo, 6University of Michigan, Ann Arbor, MI, 7Laboratório de Hormônios e Genética Molecular- LIM/42, Unidade de Adrenal, Disc. de Endocrinologia e Metabologia, Hospital das Clínicas, Faculdade de Medicina da Universidade de São Paulo, São Paulo, Brazil, 8University of São Paulo, Hospital das Clinicas, São Paulo, Brazil
Introduction: During puberty and lactation, when the pituitary gland is in high demand, a recruitment of stem/progenitor pituitary cells occurs and SOX2 is the main marker for this cell population. There is no characterization of stem cell in congenital hypopituitarism (CH) in Ames mice (harboring a spontaneous Prop1 mutation) during the pubertal period (4 weeks-4W). Aim: To characterize the expression of Sox2 and genes encoding pituitary hormones in the pubertal period in Ames mice pituitary glands. Methods: Pituitary glands were collected from three wild type and three mutant 4-week-old animals. The glands were fixed at 4% paraformaldehyde and embedded in paraffin. Pituitary sections of 3 μm were obtained from three different animals and immunohistochemistry was performed with SOX2 (ab97959, Abcam) at 1:1600 dilution upon citric acid boiling epitope exposure. Afterwards, they were amplified with a polymer and developed with DAB. RT-qPCR was performed to analyze the expression of Sox2 by TaqMan™ (Mm00488369_s1, Applied Biosystems) and genes codifying the hormones GH, TSH, LH/ FSH, CGA, PRL and POMC were analyzed by customized RTq-PCR assay by SYBR® Green (CAPM11120A, QIAGEN). They were normalized by four endogenous genes and the assays were performed in pools of four pituitaries for each group of mutant and wild type animals. The target genes relative quantification was performed using the mutant relatively to its age-paired wild type as a calibrator and the results were expressed as fold change. Results: SOX2 staining was similarly observed in the marginal zone and throughout the pituitary gland in both wild type and mutant pituitary. The pattern of SOX2 immunolocalization did not differ between wild type and mutant pituitary, despite the decreased size of the anterior pituitary in the mutant animals. In the mutant pituitary, Sox2 expression was decreased (4.37 fold change in relation to the wild type), wheres there was an increase expression of pituitary hormone codyfing genes (Gh: 1.02; Tsh: 0.95; Lh: 7.03; Fsh: 0.79; Cga: 0.87; Prl: 0.66; Pomc: 2.57), mainly for LH. Conclusion: Sox2 decreased expression and overexpression of pituitary hormone codyfing genes during puberty suggest the activation of a cellular differentiation process, despite the absence of Prop1. Pituitary axis recovering in mutant animals suggests the involvement of another transcription factor in the cell differentiation pathway that could compensate the lack of Prop1.
Nothing to Disclose: JMS, CVC, RVA, MFG, CSC, SAC, BBM, LRSC