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Kim T, Li D, Terasaka T, Nicholas DA, Knight VS, Yang JJ, Lawson MA. SRXN1 Is Necessary for Resolution of GnRH-Induced Oxidative Stress and Induction of Gonadotropin Gene Expression. Endocrinology 2019; 160:2543-2555. [PMID: 31504396 PMCID: PMC6779075 DOI: 10.1210/en.2019-00283] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/10/2019] [Accepted: 07/15/2019] [Indexed: 12/13/2022]
Abstract
A defining characteristic of the hypothalamus-pituitary-gonad reproductive endocrine axis is the episodic secretion of the pituitary gonadotropin hormones LH and FSH by the anterior pituitary gonadotropes. Hormone secretion is dictated by pulsatile stimulation, with GnRH released by hypothalamic neurons that bind and activate the G protein-coupled GnRH receptor expressed by gonadotropes. Hormone secretion and synthesis of gonadotropins are influenced by the amplitude and frequency of GnRH stimulation; variation in either affects the proportion of LH and FSH secreted and the differential regulation of hormone subunit gene expression. Therefore, proper decoding of GnRH signals is essential for appropriate gonadotropin synthesis and secretion. The GnRH receptor robustly activates downstream signaling cascades to facilitate exocytosis and stimulate gene expression and protein synthesis. It is necessary to rapidly quench signaling to preserve sensitivity and adaptability to changing pulse patterns. Reactive oxygen species (ROS) generated by receptor-activated oxidases fulfill the role of rapid signaling intermediates that facilitate robust and transient signaling. However, excess ROS can be detrimental and, unchecked, can confuse signal interpretation. We demonstrate that sulfiredoxin (SRXN1), an ATP-dependent reductase, is essential for normal responses to GnRH receptor signaling and plays a central role in resolution of ROS induced by GnRH stimulation. SRXN1 expression is mitogen-activated protein kinase dependent, and knockdown reduces Lhb and Fshb glycoprotein hormone subunit mRNA and promoter activity. Loss of SRXN1 leads to increased basal and GnRH-stimulated ROS levels. We conclude that SRXN1 is essential for normal responses to GnRH stimulation and plays an important role in ROS management.
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Affiliation(s)
- Taeshin Kim
- Department of Obstetrics, Gynecology, and Reproductive Sciences, University of California, San Diego, La Jolla, California
| | - Danmei Li
- Department of Obstetrics, Gynecology, and Reproductive Sciences, University of California, San Diego, La Jolla, California
| | - Tomohiro Terasaka
- Department of Obstetrics, Gynecology, and Reproductive Sciences, University of California, San Diego, La Jolla, California
| | - Dequina A Nicholas
- Department of Obstetrics, Gynecology, and Reproductive Sciences, University of California, San Diego, La Jolla, California
| | - Vashti S Knight
- Department of Obstetrics, Gynecology, and Reproductive Sciences, University of California, San Diego, La Jolla, California
| | - Joyce J Yang
- Department of Obstetrics, Gynecology, and Reproductive Sciences, University of California, San Diego, La Jolla, California
| | - Mark A Lawson
- Department of Obstetrics, Gynecology, and Reproductive Sciences, University of California, San Diego, La Jolla, California
- Correspondence: Mark A. Lawson, PhD, Department of Obstetrics, Gynecology, and Reproductive Sciences, University of California, San Diego Mail Code 0674, 9500 Gilman Drive, La Jolla, California 92093. E-mail:
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