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Abstract
Peptidases generate bioactive peptides that can regulate cell signaling and mediate intercellular communication. While the processing of peptide precursors is initiated intracellularly, some modifications by peptidases may be conducted extracellularly. Thimet oligopeptidase (TOP) is a peptidase that processes neuroendocrine peptides with roles in mood, metabolism, and immune responses, among other functions. TOP also hydrolyzes angiotensin I to angiotensin 1–7, which may be involved in the pathophysiology of COVID-19 infection. Although TOP is primarily cytosolic, it can also be associated with the cell plasma membrane or secreted to the extracellular space. Recent work indicates that membrane-associated TOP can be released with extracellular vesicles (EVs) to the extracellular space. Here we briefly summarize the enzyme’s classical function in extracellular processing of neuroendocrine peptides, as well as its more recently understood role in intracellular processing of various peptides that impact human diseases. Finally, we discuss new findings of EV-associated TOP in the extracellular space.
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Woitowich NC, Philibert KD, Leitermann RJ, Wungjiranirun M, Urban JH, Glucksman MJ. EP24.15 as a Potential Regulator of Kisspeptin Within the Neuroendocrine Hypothalamus. Endocrinology 2016; 157:820-30. [PMID: 26653570 PMCID: PMC4733123 DOI: 10.1210/en.2015-1580] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
Abstract
The neuropeptide kisspeptin (Kiss1) is integral to the advent of puberty and the generation of cyclical LH surges. Although many complex actions of Kiss1 are known, the mechanisms governing the processing/regulation of this peptide have not been unveiled. The metallo enzyme, endopeptidase 24.15 (thimet oligopeptidase), has been demonstrated to play a key role in the processing and thus the duration of action of the reproductive neuropeptide, GnRH, which signals downstream of Kiss1. Initial in silico modeling implied that Kiss1 could also be a putative substrate for EP24.15. Coincubation of Kiss1 and EP24.15 demonstrated multiple cleavages of the peptide predominantly between Arg29-Gly30 and Ser47-Phe48 (corresponding to Ser5-Phe6 in Kiss-10; Kiss-10 as a substrate had an additional cleavage between Phe6-Gly7) as determined by mass spectrometry. Vmax for the reaction was 2.37±0.09 pmol/min · ng with a Km of 19.68 ± 2.53μM, which is comparable with other known substrates of EP24.15. EP24.15 immunoreactivity, as previously demonstrated, is distributed in cell bodies, nuclei, and processes throughout the hypothalamus. Kiss1 immunoreactivity is localized primarily to cell bodies and fibers within the mediobasal and anteroventral-periventricular hypothalamus. Double-label immunohistochemistry indicated coexpression of EP24.15 and Kiss1, implicating that the regulation of Kiss1 by EP24.15 could occur in vivo. Further studies will be directed at determining the precise temporal sequence of EP24.15 effects on Kiss1 as it relates to the control of reproductive hormone secretion and treatment of fertility issues.
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Affiliation(s)
- Nicole C Woitowich
- Departments of Physiology and Biophysics (N.C.W., R.J.L., J.H.U.) and Biochemistry and Molecular Biology (N.C.W., K.D.P., M.W., M.J.G.), and Midwest Proteome Center (K.D.P., M.J.G.). Chicago Medical School, Rosalind Franklin University of Medicine and Science, North Chicago, Illinois 60064
| | - Keith D Philibert
- Departments of Physiology and Biophysics (N.C.W., R.J.L., J.H.U.) and Biochemistry and Molecular Biology (N.C.W., K.D.P., M.W., M.J.G.), and Midwest Proteome Center (K.D.P., M.J.G.). Chicago Medical School, Rosalind Franklin University of Medicine and Science, North Chicago, Illinois 60064
| | - Randy J Leitermann
- Departments of Physiology and Biophysics (N.C.W., R.J.L., J.H.U.) and Biochemistry and Molecular Biology (N.C.W., K.D.P., M.W., M.J.G.), and Midwest Proteome Center (K.D.P., M.J.G.). Chicago Medical School, Rosalind Franklin University of Medicine and Science, North Chicago, Illinois 60064
| | - Manida Wungjiranirun
- Departments of Physiology and Biophysics (N.C.W., R.J.L., J.H.U.) and Biochemistry and Molecular Biology (N.C.W., K.D.P., M.W., M.J.G.), and Midwest Proteome Center (K.D.P., M.J.G.). Chicago Medical School, Rosalind Franklin University of Medicine and Science, North Chicago, Illinois 60064
| | - Janice H Urban
- Departments of Physiology and Biophysics (N.C.W., R.J.L., J.H.U.) and Biochemistry and Molecular Biology (N.C.W., K.D.P., M.W., M.J.G.), and Midwest Proteome Center (K.D.P., M.J.G.). Chicago Medical School, Rosalind Franklin University of Medicine and Science, North Chicago, Illinois 60064
| | - Marc J Glucksman
- Departments of Physiology and Biophysics (N.C.W., R.J.L., J.H.U.) and Biochemistry and Molecular Biology (N.C.W., K.D.P., M.W., M.J.G.), and Midwest Proteome Center (K.D.P., M.J.G.). Chicago Medical School, Rosalind Franklin University of Medicine and Science, North Chicago, Illinois 60064
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Larco DO, Semsarzadeh NN, Cho-Clark M, Mani SK, John Wu T. The Novel Actions of the Metabolite GnRH-(1-5) are Mediated by a G Protein-Coupled Receptor. Front Endocrinol (Lausanne) 2013; 4:83. [PMID: 23847594 PMCID: PMC3703583 DOI: 10.3389/fendo.2013.00083] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/17/2013] [Accepted: 06/24/2013] [Indexed: 12/31/2022] Open
Abstract
The gonadotropin-releasing hormone (GnRH) was originally isolated from the mammalian hypothalamus for its role as the primary regulator of reproductive function. Since its discovery, GnRH has also been shown to be located in non-hypothalamic tissues and is known to have diverse functions. Although the regulation of GnRH synthesis and release has been extensively studied, there is additional evidence to suggest that the processing of GnRH to the metabolite GnRH-(1-5) represents another layer of regulation. The focus of this review will be on the current evidence for the action of the pentapeptide metabolite GnRH-(1-5) in regulating cellular migration. We discuss the potential role of GnRH-(1-5) in regulating GnRH neuronal migration during development. Furthermore, we demonstrate these actions are mediated by the activation of a G protein-coupled receptor. Our findings suggest that GnRH-(1-5) may play a developmental function in addition to regulating developing cells.
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Affiliation(s)
- Darwin Omar Larco
- Program in Molecular and Cellular Biology, Uniformed Services University of the Health Sciences, Bethesda, MD, USA
| | - Nina Nashat Semsarzadeh
- Department of Obstetrics and Gynecology, Uniformed Services University of the Health Sciences, Bethesda, MD, USA
| | - Madelaine Cho-Clark
- Department of Obstetrics and Gynecology, Uniformed Services University of the Health Sciences, Bethesda, MD, USA
| | - Shaila K. Mani
- Department of Molecular and Cellular Biology, Baylor College of Medicine, Houston, TX, USA
- Department of Neuroscience, Baylor College of Medicine, Houston, TX, USA
| | - T. John Wu
- Program in Molecular and Cellular Biology, Uniformed Services University of the Health Sciences, Bethesda, MD, USA
- Department of Obstetrics and Gynecology, Uniformed Services University of the Health Sciences, Bethesda, MD, USA
- *Correspondence: T. John Wu, Department of Obstetrics and Gynecology, Uniformed Services University, 4301 Jones Bridge Road, Bethesda, MD 20814, USA e-mail:
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Bruce LA, Cyr NE, Qiao JW, DeFries CC, Tetel MJ, Wolfson AJ. Neuropeptidase activity is down-regulated by estradiol in steroid-sensitive regions of the hypothalamus in female mice. Neuropeptides 2012; 46:167-72. [PMID: 22672888 PMCID: PMC3404208 DOI: 10.1016/j.npep.2012.04.002] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/18/2012] [Revised: 03/26/2012] [Accepted: 04/24/2012] [Indexed: 11/16/2022]
Abstract
Thimet oligopeptidase (TOP) and prolyl endopeptidase (PEP) are neuropeptidases involved in the hydrolysis of gonadotropin-releasing hormone, a key component of the hypothalamic-pituitary-gonadal axis. GnRH is regulated in part by feedback from steroid hormones such as estradiol. Previously, we demonstrated that TOP levels are down-regulated by estradiol in reproductively-relevant regions of the female rodent brain. The present study supports these findings by showing that TOP enzyme activity, as well as protein levels, in the ventromedial hypothalamic nucleus of female mice is controlled by estradiol. We further demonstrate that PEP levels in this same brain region are down-regulated by estradiol in parallel with those of TOP. These findings provide evidence that these neuropeptidases are part of the fine control of hormone levels in the HPG axis.
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Affiliation(s)
- Lisa A. Bruce
- Chemistry Department, Wellesley College, Wellesley, MA. USA
| | - Nicole E. Cyr
- Chemistry Department, Wellesley College, Wellesley, MA. USA
| | - Jana W. Qiao
- Chemistry Department, Wellesley College, Wellesley, MA. USA
| | | | - Marc J. Tetel
- Neuroscience Program, Wellesley College, Wellesley, MA. USA
| | - Adele J. Wolfson
- Chemistry Department, Wellesley College, Wellesley, MA. USA
- Corresponding author: Chemistry Department, Wellesley College, 106 Central St., Wellesley, MA 01746 USA; 781-283-3106 (tel); 781-283-3642 (fax);
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