Estrogen Receptor 1 (ESR1) Enhances Slc2a4/GLUT4 Expression by a SP1 Cooperative Mechanism

Author(s)

Barreto-Andrade, Joao Nilton ^[1] ; de Fatima, Luciana Alves ^[1] ; Campello, Raquel Saldanha ^[1] ; Cipriano Guedes, Jose Augusto ^[1] ; de Freitas, Helayne Soares ^[1] ; Ubiratan Fabres Machado, Maristela Mitiko Okamoto ^[1]

Affiliation

^[1] Univ Sao Paulo, Inst Biomed Sci, Dept Physiol & Biophys, Av Prof Lineu Prestes 1524, BR-05508900 Sao Paulo, SP - Brazil

• Document type: Journal article
• Source: INTERNATIONAL JOURNAL OF MEDICAL SCIENCES; v. 15, n. 12, p. 1320-1328, 2018.
• Web of Science Citations: 1

Abstract

Background: Estrogens are involved in glycemic regulation, playing an important role in the development and/or progression of insulin resistance. For that, estrogens regulate the expression of the glucose transporter protein GLUT4 (codified by the solute carrier family 2 member 4 gene, Slc2a4), thus modulating adipose and muscle glucose disposal. This regulation is a balance between ESR1-mediated enhancer effect and ESR2-mediated repressor effect on Slc2a4 gene. However, molecular mechanisms involved in these effects are poorly understood. Since the specificity protein 1 (SP1) participates in several ESR-mediated genomic regulations, the aim of the present study is to investigate the participation of SP1 in the ESR1/2-mediated regulation of Slc2a4 gene. Methods: Differentiated 3T3-L1 adipocytes were 24-hour challenged with 10 nM estradiol (E2) and 10 nM ESR1 agonist (PPT) or 100 nM ESR2 agonist (DPN), added or not with E2. Slc2a4 and Spl mRNAs (RT-qPCR), total GLUT4 and nuclear ESR1, ESR2 and SP1 proteins (Western blotting), SP1 binding activity into Slc2a4 promoter (EMSA), and nuclear complexation of SP1/ESR1 (immunoprecipitation) were analyzed. Results: E2 and PPT increased (25-50%) whereas DPN reduced (20-45%) Slc2a4 and GLUT4 expression. Nuclear content of ESR1 and ESR2 remained unchanged. Nuclear content of SP1 increased (50 to 90%) by PPT and DPN added or not with E2; the highest effect observed with PPT alone. PPT also increased the nuclear content of SP1/ESR1 complex and the SP1 binding into the Slc2a4 promoter. Conclusions: ESR1 activation in adipocytes increased the nuclear content of SP1 protein, the SP1/ESR1 interaction and SP1 binding into the Slc2a4 gene promoter, culminating with increased Slc2a4/GLUT4 expression. No involvement of SP1 seems to occur in ESR2-mediated repressor effect on Slc2a4. We expect that this ESR1/SP1 cooperative effect can contribute to the development of new approaches for prevention or treatment of insulin resistance and diabetes mellitus. (AU)

• FAPESP's process: 16/15603-0 - Unraveling mechanisms of glycemic control and chronic complications of Diabetes mellitus: contributions to human health
• Grantee: Ubiratan Fabres Machado
• Support Opportunities: Research Projects - Thematic Grants
• FAPESP's process: 15/18715-1 - Participation of the transcription factor SP1 in estradiolinduced regulation of Slc2a4/GLUT4 expression in adipocytes 3T3L1
• Grantee: João Nilton Barreto Andrade
• Support Opportunities: Scholarships in Brazil - Master