1
|
Vélez EJ, Nasri A, Unniappan S. Nesfatin-1 and Nesfatin-1-like peptide suppress basal and TRH-Induced expression of prolactin and prolactin regulatory element-binding protein mRNAs in rat GH3 somatolactotrophs. Mol Cell Endocrinol 2021; 529:111269. [PMID: 33819522 DOI: 10.1016/j.mce.2021.111269] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/12/2021] [Revised: 03/20/2021] [Accepted: 03/29/2021] [Indexed: 11/23/2022]
Abstract
Prolactin (PRL), mainly synthesized and secreted by the lactotrophs and somatolactotrophs of the anterior pituitary, is a pleiotropic hormone that regulates lactation. In the last decade, nesfatin-1 (NESF) and NESF-like peptide (NLP), encoded in nucleobindin 1 and 2 (NUCB1 and NUCB2), respectively, were characterized as metabolic factors with a potential role in the control of pituitary hormones. We hypothesized that NUCBs and their encoded peptides (NESF and NLP) suppress PRL transcription in the pituitary. The main objective of this research was to determine whether exogenous NESF and NLP, and/or endogenous NUCB1 and NUCB2 regulate the expression of prl and preb mRNAs. Using immortalized rat somatolactotrophs (GH3 cells), dose-response studies were performed to test whether NESF and NLP affect prl and preb. Moreover, the ability of these peptides to modulate the effects of the PRL stimulator thyrotropin releasing hormone (TRH) was studied. Besides, the effects of siRNA-mediated knockdown of endogenous NUCBs on prl and preb mRNAs were determined. NESF and NLP reduced the transcription of prl and preb in GH3 cells. Both NESF and NLP also prevented the stimulatory effects of TRH prl and preb expression. The knockdown of endogenous NUCB1 attenuates both basal prl and TRH-induced expression of prl and preb, while the silencing of NUCBs did not affect the actions of exogenous NESF or NLP. Overall, this work reveals that NUCBs and encoded-peptides are novel regulators of PRL. Future research should test whether the effects observed here in GH3 cells are preserved both in vivo and at the post-transcriptional level.
Collapse
Affiliation(s)
- Emilio J Vélez
- Laboratory of Integrative Neuroendocrinology, Department of Veterinary Biomedical Sciences, Western College of Veterinary Medicine, University of Saskatchewan, Saskatoon, Canada
| | - Atefeh Nasri
- Laboratory of Integrative Neuroendocrinology, Department of Veterinary Biomedical Sciences, Western College of Veterinary Medicine, University of Saskatchewan, Saskatoon, Canada
| | - Suraj Unniappan
- Laboratory of Integrative Neuroendocrinology, Department of Veterinary Biomedical Sciences, Western College of Veterinary Medicine, University of Saskatchewan, Saskatoon, Canada.
| |
Collapse
|
2
|
Leem J, Shim HM, Cho H, Park JH. Octanoic acid potentiates glucose-stimulated insulin secretion and expression of glucokinase through the olfactory receptor in pancreatic β-cells. Biochem Biophys Res Commun 2018; 503:278-284. [PMID: 29885841 DOI: 10.1016/j.bbrc.2018.06.015] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/28/2018] [Accepted: 06/07/2018] [Indexed: 12/30/2022]
Abstract
Olfactory receptors (ORs) are G protein-coupled receptors that mediate olfactory chemosensation, leading to the perception of smell. ORs are expressed in many tissues, but their functions are largely unknown. Here, we show that the olfactory receptor Olfr15 is highly and selectively expressed in both mouse pancreatic β-cells and MIN6 cells. In addition, octanoic acid (OA), a medium-chain fatty acid, potentiates glucose-stimulated insulin secretion (GSIS). The OA-induced enhancement of GSIS was inhibited by Olfr15 knockdown. Treatment with a PLC inhibitor or an Ins(1,4,5)P3 receptor (IP3R) antagonist also blocked the OA-induced enhancement of GSIS. These results suggest that OA potentiates GSIS via Olfr15 though the PLC-IP3 pathway. Furthermore, long-term treatment with OA increased cellular glucose uptake in MIN6 cells by up-regulating the expression of glucokinase (GK). Moreover, this process was blocked by an IP3R antagonist and a Ca2+/calmodulin-dependent protein kinase kinase (CaMKK) inhibitor. Similarly, OA stimulated GK promoter activity, while either Olfr15 or CaMKIV knockdown blocked the stimulatory effect of OA on GK promoter activity. These results suggest that long-term treatment of OA induces GK promoter activity via Olfr15 through the IP3-CaMKK/CaMKIV pathway. In islets from type 2 diabetic mice, the expression level of Olfr15 and the OA-induced enhancement of GSIS were strongly reduced. Collectively, our results highlight the crucial role of the olfactory receptor Olfr15 in potentiating GSIS in pancreatic β-cells, suggesting that Olfr15 may be an important therapeutic target in type 2 diabetes.
Collapse
Affiliation(s)
- Jaechan Leem
- Department of Immunology, School of Medicine, Catholic University of Daegu, Daegu, 42472, South Korea
| | - Hae-Min Shim
- Department of Physiology, School of Medicine, Keimyung University, Daegu, 42601, South Korea
| | - Hochan Cho
- Division of Endocrinology, Department of Internal Medicine, Keimyung University Dongsan Medical Center, Daegu, 41931, South Korea
| | - Jae-Hyung Park
- Department of Physiology, School of Medicine, Keimyung University, Daegu, 42601, South Korea; Institute for Medical Science, Keimyung University, Daegu, 42601, South Korea.
| |
Collapse
|
3
|
Park JM, Kim MY, Kim TH, Min DK, Yang GE, Ahn YH. Prolactin regulatory element-binding (PREB) protein regulates hepatic glucose homeostasis. Biochim Biophys Acta Mol Basis Dis 2018; 1864:2097-2107. [PMID: 29601978 DOI: 10.1016/j.bbadis.2018.03.024] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/11/2017] [Revised: 02/24/2018] [Accepted: 03/26/2018] [Indexed: 01/22/2023]
Abstract
Prolactin regulatory element-binding (PREB) protein is a transcription factor that regulates prolactin (PRL) gene expression. PRL, also known as luteotropic hormone or luteotropin, is well known for its role in producing milk. However, the role of PREB, in terms of hepatic glucose metabolism, is not well elucidated. Here, we observed expression of Preb in the mouse liver, in connection with glucose homeostasis. Morevoer, Preb was downregulated in db/db, ob/ob and high-fat diet-induced obese (DIO) mice, concurrent with upregulation of the liver genes glucose-6-phosphatase (G6pc) and phosphoenolpyruvate carboxykinase-1 (Pck). Administration of adenovirus-Preb (Ad-Preb) to db/db, ob/ob, and DIO mice diminished glucose, insulin, and pyruvate tolerance, which analogously, were impaired in normal (C57BL/6) mice knocked down for Preb, via infection with Ad-shPreb (anti-Preb RNA), indicating Preb to be a negative regulator of liver gluconeogenic genes. We further demonstrate that Preb negatively influences gluconeogenic gene expression, by directly binding to their promoters at a prolactin core-binding element (PCBE). A better understanding of Preb gene expression, during the pathogenesis of hepatic insulin resistance, could ultimately provide new avenues for therapies for metabolic syndrome, obesity, and type-2 diabetes mellitus, disorders whose worldwide incidences are increasing drastically.
Collapse
Affiliation(s)
- Joo-Man Park
- Department of Biochemistry and Molecular Biology, Brain Korea 21 Project for Medical Sciences, Yonsei University College of Medicine, 50-1 Yonsei-ro, Seodaemun-gu, Seoul 03722, Republic of Korea
| | - Mi-Young Kim
- Department of Biochemistry and Molecular Biology, Brain Korea 21 Project for Medical Sciences, Yonsei University College of Medicine, 50-1 Yonsei-ro, Seodaemun-gu, Seoul 03722, Republic of Korea
| | - Tae-Hyun Kim
- Department of Biochemistry and Molecular Biology, Brain Korea 21 Project for Medical Sciences, Yonsei University College of Medicine, 50-1 Yonsei-ro, Seodaemun-gu, Seoul 03722, Republic of Korea
| | - Dong-Kook Min
- Department of Biochemistry and Molecular Biology, Brain Korea 21 Project for Medical Sciences, Yonsei University College of Medicine, 50-1 Yonsei-ro, Seodaemun-gu, Seoul 03722, Republic of Korea
| | - Ga Eul Yang
- Department of Biochemistry and Molecular Biology, Brain Korea 21 Project for Medical Sciences, Yonsei University College of Medicine, 50-1 Yonsei-ro, Seodaemun-gu, Seoul 03722, Republic of Korea
| | - Yong-Ho Ahn
- Department of Biochemistry and Molecular Biology, Brain Korea 21 Project for Medical Sciences, Yonsei University College of Medicine, 50-1 Yonsei-ro, Seodaemun-gu, Seoul 03722, Republic of Korea.
| |
Collapse
|
4
|
Characterization and Expression of Turkey Prolactin Regulatory Element Binding in the Anterior Pituitary Gland and Pancreas During Embryogenesis. J Poult Sci 2016; 53:67-75. [PMID: 32908367 PMCID: PMC7477242 DOI: 10.2141/jpsa.0150091] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022] Open
Abstract
The PRL regulatory element-binding (PREB) protein is a transcription factor that was originally cloned from the rat anterior pituitary gland and characterized as a regulator of the PRL promoter. It is also strongly expressed in several extrapituitary tissues; however, its functional role is not well understood to date. In this study, we aimed to clone and characterize the turkey PREB gene and investigate its mRNA expression in the anterior pituitary gland and pancreas during embryogenesis. Based on the conserved sequence of chicken and mammalian PREB cDNAs, a turkey PREB cDNA fragment was obtained, and after sequencing of the fragment, the 5′-and 3′-ends of mRNA were amplified and determined. To identify the PREB gene structure, polymerase chain reaction (PCR) amplification was performed. The turkey PREB gene consists of 9 exons and 8 introns, and it encodes a 411-amino-acid protein. The expression of PREB mRNA in the anterior pituitary gland was measured during embryogenesis. Levels of PREB mRNA significantly increased at embryonic day 22, with maximum levels being detected on day 25 of ontogeny, which correlated with similar changes in levels of PRL mRNA. The highest level of PREB mRNA was detected on day 19 in the pancreas. However, the highest level of insulin mRNA was detected at embryonic day 25. These results indicate that PREB may be involved in the expression of PRL mRNA in the anterior pituitary gland, whereas insulin mRNA may be expressed independently of the expression of PREB mRNA in the pancreas during embryogenesis.
Collapse
|
5
|
Miyai Y, Murao K, Imachi H, Li J, Nishiuchi Y, Masugata H, Iwama H, Kushida Y, Ishida T, Haba R. Exendin-4 regulates the expression of the ATP-binding cassette transporter A1 via transcriptional factor PREB in the pancreatic β cell line. J Endocrinol Invest 2011; 34:e268-74. [PMID: 21521937 DOI: 10.3275/7683] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/06/2023]
Abstract
BACKGROUND PRL regulatory element-binding (PREB) protein is a transcription factor that regulates insulin promoter activity in the rat anterior pituitary. The PREB protein is expressed not only in the anterior pituitary but also in pancreatic β cells. Previously, we have reported that PREB plays an important role in glucose-mediated insulin gene expression in pancreatic β cells. The ATP-binding cassette transporter A1 (ABCA1) in pancreatic β cells influences insulin secretion and glucose homeostasis. Exendin-4 (Ex-4), a longacting agonist of the glucagon-like peptide 1, stimulates ABCA1 expression in pancreatic β cells. AIMS In this study, we examined the role played by PREB in Ex-4-induced ABCA1 expression in pancreatic β cells. MATERIAL/SUBJECTS AND METHODS PREB mRNA and protein expression were evaluated in pancreatic β cell line (INS-1 cells) treated with Ex-4 (10 nM). RESULTS Ex-4 stimulated PREB protein and mRNA expression in INS-1 cells. PREB stimulated the activity of the luciferase reporter protein that was under the control of the ABCA1 promoter. Chromatin immunoprecipitation assay showed that PREB mediates its transcriptional activity by directly binding to the ABCA1 promoter region. Finally, we used small interfering RNA to inhibit PREB expression in the cells and demonstrated that the knockdown of PREB expression attenuated the effects of Ex-4 on ABCA1 expression. CONCLUSION PREB mediates Ex-4-stimulated transcription of the ABCA1 gene in pancreatic β cells.
Collapse
Affiliation(s)
- Y Miyai
- Department of diagnostic pathology, Kagawa University, Miki-cho, Kita-gun, Kagawa, Japan
| | | | | | | | | | | | | | | | | | | |
Collapse
|