1
|
O’Sullivan JJ, Uyeda KS, Stevenson MJ, Heffern MC. Investigation of metal modulation of oxytocin structure receptor-mediated signaling. RSC Chem Biol 2023; 4:165-172. [PMID: 36794023 PMCID: PMC9906307 DOI: 10.1039/d2cb00225f] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/09/2022] [Accepted: 12/16/2022] [Indexed: 01/06/2023] Open
Abstract
Oxytocin is a 9-amino acid peptide hormone. Since its discovery in 1954, it has most commonly been studied in relation to its role in stimulating parturition and lactation. However, it is now known that oxytocin has a widely diverse set of functions throughout the body including neuromodulation, bone growth, and inflammation. Previous research has suggested that divalent metal ions may be required for oxytocin activity, but the exact metal species and specific pathways have yet to be fully elucidated. In this work, we focus on characterizing copper and zinc bound forms of oxytocin and related analogs through far-UV circular dichroism. We report that Cu(ii) and Zn(ii) bind uniquely to oxytocin and all analogs investigated. Furthermore, we investigate how these metal bound forms may affect downstream signaling of MAPK activation upon receptor binding. We find that both Cu(ii) and Zn(ii) bound oxytocin attenuates the activation of the MAPK pathway upon receptor binding relative to oxytocin alone. Interestingly, we observed that Zn(ii) bound forms of linear oxytocin facilitate increased MAPK signaling. This study lays the foundation for future work on elucidating the metal effects on oxytocin's diverse bioactivity.
Collapse
Affiliation(s)
| | - Kylie S. Uyeda
- Department of Chemistry, University of California, DavisDavisCA95616USA
| | | | - Marie C. Heffern
- Department of Chemistry, University of California, DavisDavisCA95616USA
| |
Collapse
|
2
|
Wei J, Zheng H, Li G, Chen Z, Fang G, Yan J. Involvement of oxytocin receptor deficiency in psychiatric disorders and behavioral abnormalities. Front Cell Neurosci 2023; 17:1164796. [PMID: 37153633 PMCID: PMC10159063 DOI: 10.3389/fncel.2023.1164796] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/13/2023] [Accepted: 03/24/2023] [Indexed: 05/10/2023] Open
Abstract
Oxytocin and its target receptor (oxytocin receptor, OXTR) exert important roles in the regulation of complex social behaviors and cognition. The oxytocin/OXTR system in the brain could activate and transduce several intracellular signaling pathways to affect neuronal functions or responses and then mediate physiological activities. The persistence and outcome of the oxytocin activity in the brain are closely linked to the regulation, state, and expression of OXTR. Increasing evidence has shown that genetic variations, epigenetic modification states, and the expression of OXTR have been implicated in psychiatric disorders characterized by social deficits, especially in autism. Among these variations and modifications, OXTR gene methylation and polymorphism have been found in many patients with psychiatric disorders and have been considered to be associated with those psychiatric disorders, behavioral abnormalities, and individual differences in response to social stimuli or others. Given the significance of these new findings, in this review, we focus on the progress of OXTR's functions, intrinsic mechanisms, and its correlations with psychiatric disorders or deficits in behaviors. We hope that this review can provide a deep insight into the study of OXTR-involved psychiatric disorders.
Collapse
Affiliation(s)
- Jinbao Wei
- Department of Pharmacy, Fujian Maternity and Child Health Hospital, College of Clinical Medicine for Obstetrics and Gynecology and Pediatrics, Fujian Medical University, Fuzhou, Fujian, China
- Department of Pharmacy, Ningde Municipal Hospital Affiliated to Ningde Normal University, Ningde, Fujian, China
| | - Huanrui Zheng
- Department of Pharmacy, Fujian Maternity and Child Health Hospital, College of Clinical Medicine for Obstetrics and Gynecology and Pediatrics, Fujian Medical University, Fuzhou, Fujian, China
- Fujian Key Laboratory of Women and Children's Critical Diseases Research, Fujian Maternity and Child Health Hospital, Fuzhou, Fujian, China
| | - Guokai Li
- Fujian Key Laboratory of Women and Children's Critical Diseases Research, Fujian Maternity and Child Health Hospital, Fuzhou, Fujian, China
| | - Zichun Chen
- Department of Pharmacy, Ningde Municipal Hospital Affiliated to Ningde Normal University, Ningde, Fujian, China
| | - Gengjing Fang
- Fujian Key Laboratory of Women and Children's Critical Diseases Research, Fujian Maternity and Child Health Hospital, Fuzhou, Fujian, China
- NHC Key Laboratory of Technical Evaluation of Fertility Regulation for Non-human Primate (Fujian Maternity and Child Health Hospital), Fuzhou, Fujia, China
- Gengjing Fang
| | - Jianying Yan
- Fujian Key Laboratory of Women and Children's Critical Diseases Research, Fujian Maternity and Child Health Hospital, Fuzhou, Fujian, China
- Department of Obstetrics, Fujian Maternity and Child Health Hospital, College of Clinical Medicine for Obstetrics and Gynecology and Pediatrics, Fujian Medical University, Fuzhou, Fujian, China
- *Correspondence: Jianying Yan
| |
Collapse
|
3
|
Triana-Del Rio R, Ranade S, Guardado J, LeDoux J, Klann E, Shrestha P. The modulation of emotional and social behaviors by oxytocin signaling in limbic network. Front Mol Neurosci 2022; 15:1002846. [PMID: 36466805 PMCID: PMC9714608 DOI: 10.3389/fnmol.2022.1002846] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/25/2022] [Accepted: 09/22/2022] [Indexed: 01/21/2024] Open
Abstract
Neuropeptides can exert volume modulation in neuronal networks, which account for a well-calibrated and fine-tuned regulation that depends on the sensory and behavioral contexts. For example, oxytocin (OT) and oxytocin receptor (OTR) trigger a signaling pattern encompassing intracellular cascades, synaptic plasticity, gene expression, and network regulation, that together function to increase the signal-to-noise ratio for sensory-dependent stress/threat and social responses. Activation of OTRs in emotional circuits within the limbic forebrain is necessary to acquire stress/threat responses. When emotional memories are retrieved, OTR-expressing cells act as gatekeepers of the threat response choice/discrimination. OT signaling has also been implicated in modulating social-exposure elicited responses in the neural circuits within the limbic forebrain. In this review, we describe the cellular and molecular mechanisms that underlie the neuromodulation by OT, and how OT signaling in specific neural circuits and cell populations mediate stress/threat and social behaviors. OT and downstream signaling cascades are heavily implicated in neuropsychiatric disorders characterized by emotional and social dysregulation. Thus, a mechanistic understanding of downstream cellular effects of OT in relevant cell types and neural circuits can help design effective intervention techniques for a variety of neuropsychiatric disorders.
Collapse
Affiliation(s)
| | - Sayali Ranade
- Department of Neurobiology and Behavior, School of Medicine, Stony Brook University, Stony Brook, NY, United States
| | - Jahel Guardado
- Center for Neural Science, New York University, New York, NY, United States
| | - Joseph LeDoux
- Center for Neural Science, New York University, New York, NY, United States
| | - Eric Klann
- Center for Neural Science, New York University, New York, NY, United States
| | - Prerana Shrestha
- Department of Neurobiology and Behavior, School of Medicine, Stony Brook University, Stony Brook, NY, United States
| |
Collapse
|
4
|
Xu Q, Zhuo K, Zhang X, Zhang Y, Xue J, Zhou MS. Oxytocin-induced endothelial nitric oxide dependent vasorelaxation and ERK1/2-mediated vasoconstriction in the rat aorta. THE KOREAN JOURNAL OF PHYSIOLOGY & PHARMACOLOGY 2022; 26:255-262. [PMID: 35766003 PMCID: PMC9247708 DOI: 10.4196/kjpp.2022.26.4.255] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 12/10/2021] [Revised: 02/14/2022] [Accepted: 02/21/2022] [Indexed: 11/20/2022]
Abstract
Oxytocin is a neuropeptide produced primarily in the hypothalamus and plays an important role in the regulation of mammalian birth and lactation. It has been shown that oxytocin has important cardiovascular protective effects. Here we investigated the effects of oxytocin on vascular reactivity and underlying the mechanisms in human umbilical vein endothelial cells (HUVECs) in vitro and in rat aorta ex vivo. Oxytocin increased phospho-eNOS (Ser 1177) and phospho-Akt (Ser 473) expression in HUVECs in vitro and the aorta of rat ex vivo. Wortmannin, a specific inhibitor of phosphatidylinositol 3-kinase (PI3K), inhibited oxytocin-induced Akt and eNOS phosphorylation. In the rat aortic rings, oxytocin induced a biphasic vascular reactivity: oxytocin at low dose (10-9–10-8 M) initiated a vasorelaxation followed by a vasoconstriction at high dose (10-7 M). L-NAME (a nitric oxide synthase inhibitor), endothelium removal or wortmannin abolished oxytocin-induced vasorelaxation, and slightly enhanced oxytocin-induced vasoconstriction. Atosiban, an oxytocin/vasopressin 1a receptor inhibitor, totally blocked oxytocin-induced relaxation and vasoconstriction. PD98059 (ERK1/2 inhibitor) partially inhibited oxytocin-induced vasoconstriction. Oxytocin also increased aortic phospho-ERK1/2 expression, which was reduced by either atosiban or PD98059, suggesting that oxytocin-induced vasoconstriction was partially mediated by oxytocin/V1aR activation of ERK1/2. The present study demonstrates that oxytocin can activate different signaling pathways to cause vasorelaxation or vasoconstriction. Oxytocin stimulation of PI3K/eNOS-derived nitric oxide may participate in maintenance of cardiovascular homeostasis, and different vascular reactivities to low or high dose of oxytocin suggest that oxytocin may have different regulatory effects on vascular tone under physiological or pathophysiological conditions.
Collapse
Affiliation(s)
- Qian Xu
- Department of Physiology, Shenyang Medical University, Shenyang 110034, P.R. China
| | - Kunping Zhuo
- Department of Physiology, Shenyang Medical University, Shenyang 110034, P.R. China
| | - Xiaotian Zhang
- Department of Physiology, Shenyang Medical University, Shenyang 110034, P.R. China
| | - Yaoxia Zhang
- Department of Physiology, Shenyang Medical University, Shenyang 110034, P.R. China
| | - Jiaojiao Xue
- Department of Physiology, Shenyang Medical University, Shenyang 110034, P.R. China
| | - Ming-Sheng Zhou
- Department of Physiology, Shenyang Medical University, Shenyang 110034, P.R. China
| |
Collapse
|
5
|
Li D, Liu X, Li T, Wang X, Jia S, Wang P, Wang YF. Involvement of Protein Kinase A in Oxytocin Neuronal Activity in Rat Dams with Pup Deprivation. Neurochem Res 2021; 46:980-991. [PMID: 33611682 DOI: 10.1007/s11064-020-03218-5] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/07/2020] [Revised: 12/20/2020] [Accepted: 12/27/2020] [Indexed: 10/22/2022]
Abstract
Oxytocin (OT) neuronal activity is the key factor for breastfeeding and it can be disrupted by mother-baby separation. To explore cellular mechanisms underlying OT neuronal activity, we studied the role of protein kinase A (PKA) in OT neuronal activity in the supraoptic nucleus (SON) using a rodent model of pup deprivation (PD) Intermittent (IPD) or continuous (CPD) PD significantly reduced suckling duration and number of milk ejections in lactating rats, particularly those with CPD. In Western blots of the SON, PD increased expressions of OT receptor (OTR) and its immediate downstream effectors, Gαq and Gβ subunits, particularly IPD, but reduced the expression of catalytic subunit of PKA (cPKA). In brain slices, inhibition of PKA blocked prostaglandin E2-evoked increase in firing activity including burst firing in OT neurons. In IPD dams, filamentous actin formed ring-like structures in the cytoplasmic region of OT neurons, which was reduced in CPD. Moreover, molecular association between actin and cPKA also reduced in PD dams. Incubation of brain slices with OT reduced the expression of cPKA, which was blocked by pretreatment with atosiban, an antagonist of OTR. These results indicate that PD disrupts OT neuronal activity through dissociating the Gq proteins and PKA in OTR-associated signaling cascade, which couples with reduced interactions between filamentous actin and PKA in OT neurons in the SON. This study highlights that PKA can be a novel target treating abnormal OT neuronal activity and its associated diseases.
Collapse
Affiliation(s)
- Dongyang Li
- Department of Physiology, School of Basic Medical Sciences, Harbin Medical University, Harbin, 150081, China
- Department of Physiology, Hainan Medical University, Haikou, China
| | - Xiaoyu Liu
- Department of Physiology, School of Basic Medical Sciences, Harbin Medical University, Harbin, 150081, China
| | - Tong Li
- Department of Physiology, School of Basic Medical Sciences, Harbin Medical University, Harbin, 150081, China
| | - Xiaoran Wang
- Department of Physiology, School of Basic Medical Sciences, Harbin Medical University, Harbin, 150081, China
| | - Shuwei Jia
- Department of Physiology, School of Basic Medical Sciences, Harbin Medical University, Harbin, 150081, China
| | - Ping Wang
- Department of Genetics, School of Basic Medical Sciences, Harbin Medical University, Harbin, 150081, China
| | - Yu-Feng Wang
- Department of Physiology, School of Basic Medical Sciences, Harbin Medical University, Harbin, 150081, China.
| |
Collapse
|
6
|
Oxytocin Downregulates the Ca V1.2 L-Type Ca 2+ Channel via Gi/cAMP/PKA/CREB Signaling Pathway in Cardiomyocytes. MEMBRANES 2021; 11:membranes11040234. [PMID: 33806201 PMCID: PMC8066716 DOI: 10.3390/membranes11040234] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 02/25/2021] [Revised: 03/17/2021] [Accepted: 03/24/2021] [Indexed: 12/13/2022]
Abstract
Oxytocin (OT) and its receptor (OTR) are expressed in the heart and are involved in the physiological cardiovascular functional system. Although it is known that OT/OTR signaling is cardioprotective by reducing the inflammatory response and improving cardiovascular function, the role of OT in the cardiac electrical excitation modulation has not been clarified. This study investigates the molecular mechanism of the action of OT on cardiomyocyte membrane excitation focusing on the L-type Ca2+ channel. Our methodology uses molecular biological methods and a patch-clamp technique on rat cardiomyocytes with OT, combined with several signal inhibitors and/or activators. Our results show that long-term treatment of OT significantly decreases the expression of Cav1.2 mRNA, and reduces the L-type Ca2+ channel current (ICa.L) in cardiomyocytes. OT downregulates the phosphorylated component of a transcription factor adenosine-3′,5′-cyclic monophosphate (cAMP) response element binding protein (CREB), whose action is blocked by OTR antagonist and pertussis toxin, a specific inhibitor of the inhibitory GTP-binding regulators of adenylate cyclase, Gi. On the other hand, the upregulation of Cav1.2 mRNA expression by isoproterenol is halted by OT. Furthermore, inhibition of phospholipase C (PLC) was without effect on the OT action to downregulate Cav1.2 mRNA—which suggests a signal pathway of Gi/protein kinase A (PKA)/CREB mediated by OT/OTR. These findings indicate novel signaling pathways of OT contributing to a downregulation of the Cav1.2-L-type Ca2+ channel in cardiomyocytes.
Collapse
|
7
|
Li D, Liu X, Liu H, Li T, Jia S, Wang X, Wang P, Qin D, Wang YF. Key Roles of Cyclooxygenase 2-Protein Kinase A-Hyperpolarization-activated Cyclic Nucleotide-gated Channel 3 Pathway in the Regulation of Oxytocin Neuronal Activity in Lactating Rats with Intermittent Pup-Deprivation. Neuroscience 2020; 452:13-25. [PMID: 33137408 DOI: 10.1016/j.neuroscience.2020.10.016] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/21/2020] [Accepted: 10/09/2020] [Indexed: 12/14/2022]
Abstract
Suckling-evoked pulsatile release of oxytocin (OT) from the posterior pituitary plays a key role in breastfeeding, which relies on burst-like discharges of OT neurons. To explore cellular mechanisms regulating OT neuronal activity, using lactating rats with pup-deprivation (PD) during postpartum day 1-5, we observed the involvement of prostaglandin, cyclic AMP/protein kinase A (PKA) and hyperpolarization-activated cyclic nucleotide-gated channel 3 (HCN3) signaling pathway in OT neuronal activity. PD gradually reduced lactation efficiency. Intermittent PD (IPD) was largely reversed by intranasally-applied OT (IAO) but not by hypodermically-applied OT. IPD caused involution-like histological changes in the mammary glands, increased hypothalamic OT release but did not influence plasma OT concentrations. In the supraoptic nucleus, IPD increased OT receptor (OTR) expressions in OT neurons as well as Gαq subunit, Gβ subunit and cyclooxygenase 2 (Cox-2). These effects except that on Gβ subunit were reversed by IAO. Notably, IPD increased the expression of catalytic subunit of PKA in the SON, specifically in vasopressin neurons but not in OT neurons. In addition, IPD increased the expression of HCN3. IAO partially reversed these changes in the SON. Lastly, blocking HCN3 blocked excitation and burst firing in OT neurons-evoked by prostaglandin E2, a key mediator of OT-evoked burst firing; blocking Cox-2 or PKA reduced the molecular association between OTR and HCN3. Thus, there is a prostaglandin-cAMP/PKA-HCN3 pathway in the regulation of OT neuronal activity. PD disrupts lactation performance through uncoupling OTR and PKA-HCN3 signaling. The reversal effect of IAO highlights its therapeutic potential in PD-evoked hypogalactia.
Collapse
Affiliation(s)
- Dongyang Li
- Department of Physiology, School of Basic Medical Sciences, Harbin Medical University, Harbin, China
| | - Xiaoyu Liu
- Department of Physiology, School of Basic Medical Sciences, Harbin Medical University, Harbin, China
| | - Haitao Liu
- Department of Physiology, School of Basic Medical Sciences, Harbin Medical University, Harbin, China
| | - Tong Li
- Department of Physiology, School of Basic Medical Sciences, Harbin Medical University, Harbin, China
| | - Shuwei Jia
- Department of Physiology, School of Basic Medical Sciences, Harbin Medical University, Harbin, China
| | - Xiaoran Wang
- Department of Physiology, School of Basic Medical Sciences, Harbin Medical University, Harbin, China
| | - Ping Wang
- Department of Genetics, School of Basic Medical Sciences, Harbin Medical University, Harbin, China
| | - Danian Qin
- Department of Physiology, Shantou University of Medical College, Shantou, China
| | - Yu-Feng Wang
- Department of Physiology, School of Basic Medical Sciences, Harbin Medical University, Harbin, China.
| |
Collapse
|
8
|
Wei J, Ma L, Ju P, Yang B, Wang YX, Chen J. Involvement of Oxytocin Receptor/Erk/MAPK Signaling in the mPFC in Early Life Stress-Induced Autistic-Like Behaviors. Front Cell Dev Biol 2020; 8:564485. [PMID: 33134294 PMCID: PMC7561716 DOI: 10.3389/fcell.2020.564485] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/21/2020] [Accepted: 09/10/2020] [Indexed: 12/13/2022] Open
Abstract
The neonatal or infant period is a critical stage for the development of brain neuroplasticity. Early life stresses in the neonatal period, including neonatal maternal separation (NMS), have adverse effects on an increased risk of psychiatric disorders in juveniles and adults. However, the underlying molecular mechanisms are not largely understood. Here, we found that juvenile rats subjected to 4 h daily NMS during postnatal days 1 to 20 exhibited autistic-like behavioral deficits without impairments in learning and memory functions. Molecular mechanism studies showed that oxytocin receptor (OXTR) in the medial prefrontal cortex of NMS rats was evidently downregulated when compared with control pups, especially in neurons. Erk/MAPK signaling, the downstream coupling signaling of OTXR, was also inhibited in NMS juvenile rats. Treatment with oxytocin could relieve NMS-induced social deficit behaviors and activated phosphorylation of Erk/MAPK signaling. Furthermore, medication with the inhibitor of H3K4 demethylase alleviated the abnormal behaviors in NMS rats and increased the expression of OXTR in the medial prefrontal cortex, which showed an epigenetic mechanism underlying social deficits induced by NMS. Taken together, these findings identified a molecular mechanism by which disruptions of mother-infant interactions influenced later displays of typical social behaviors and suggested the potential for NMS-driven epigenetic tuning of OXTR expression.
Collapse
Affiliation(s)
- Jinbao Wei
- Shanghai Key Laboratory of Psychotic Disorders, Shanghai Mental Health Center, School of Medicine, Shanghai Jiao Tong University, Shanghai, China.,King's Lab, School of Pharmacy, Shanghai Jiao Tong University, Shanghai, China.,Hubei Key Laboratory of Wudang Local Chinese Medicine Research, Institute of Wudang Traditional Chinese Medicine, Taihe Hospital, Hubei University of Medicine, Shiyan, China
| | - Le Ma
- King's Lab, School of Pharmacy, Shanghai Jiao Tong University, Shanghai, China
| | - Peijun Ju
- Shanghai Key Laboratory of Psychotic Disorders, Shanghai Mental Health Center, School of Medicine, Shanghai Jiao Tong University, Shanghai, China
| | - Beibei Yang
- Shanghai Key Laboratory of Psychotic Disorders, Shanghai Mental Health Center, School of Medicine, Shanghai Jiao Tong University, Shanghai, China
| | - Yong-Xiang Wang
- King's Lab, School of Pharmacy, Shanghai Jiao Tong University, Shanghai, China
| | - Jinghong Chen
- Shanghai Key Laboratory of Psychotic Disorders, Shanghai Mental Health Center, School of Medicine, Shanghai Jiao Tong University, Shanghai, China
| |
Collapse
|
9
|
Liu H, Gruber CW, Alewood PF, Möller A, Muttenthaler M. The oxytocin receptor signalling system and breast cancer: a critical review. Oncogene 2020; 39:5917-5932. [PMID: 32782397 PMCID: PMC7483001 DOI: 10.1038/s41388-020-01415-8] [Citation(s) in RCA: 31] [Impact Index Per Article: 7.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/29/2020] [Revised: 07/21/2020] [Accepted: 07/29/2020] [Indexed: 12/24/2022]
Abstract
Breast cancer is making up one-quarter of all new female cancer cases diagnosed worldwide. Breast cancer surgeries, radiation therapies, cytotoxic chemotherapies and targeted therapies have made significant progress and play a dominant role in breast cancer patient management. However, many challenges remain, including resistance to systemic therapies, tumour recurrence and metastasis. The cyclic neuropeptide oxytocin (OT) elicits a plethora of biological responses via the oxytocin receptor (OTR) in both the central and peripheral nervous system, including social bonding, stress, maternal behaviour, sexual activity, uterus contraction, milk ejection and cancer. As a typical member of the G protein-coupled receptor family, OTR represents also an intriguing target for cancer therapy. There is emerging evidence that OTR plays a role in breast cancer development and progression, and several breast cancer cell lines express OTR. However, despite supporting evidence that OT lowers breast cancer risks, its mechanistic role in breast cancer development and the related signalling pathways are not fully understood. Here, we review the current knowledge of the OT/OTR signalling system in healthy breast tissue as well as in breast cancer, and discuss OTR as a potential therapeutic target for breast cancer management.
Collapse
Affiliation(s)
- Huiping Liu
- Institute for Molecular Bioscience, The University of Queensland, Brisbane, QLD, 4072, Australia
| | - Christian W Gruber
- Center for Physiology and Pharmacology, Medical University of Vienna, 1090, Vienna, Austria
| | - Paul F Alewood
- Institute for Molecular Bioscience, The University of Queensland, Brisbane, QLD, 4072, Australia
| | - Andreas Möller
- Tumour Microenvironment Laboratory, QIMR Berghofer Medical Research Institute, Herston, QLD 4006, Australia
| | - Markus Muttenthaler
- Institute for Molecular Bioscience, The University of Queensland, Brisbane, QLD, 4072, Australia. .,Institute of Biological Chemistry, Faculty of Chemistry, University of Vienna, 1090, Vienna, Austria.
| |
Collapse
|
10
|
Li D, Liu X, Liu T, Liu H, Tong L, Jia S, Wang YF. Neurochemical regulation of the expression and function of glial fibrillary acidic protein in astrocytes. Glia 2019; 68:878-897. [PMID: 31626364 DOI: 10.1002/glia.23734] [Citation(s) in RCA: 85] [Impact Index Per Article: 17.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/25/2019] [Revised: 08/27/2019] [Accepted: 09/17/2019] [Indexed: 12/30/2022]
Abstract
Glial fibrillary acidic protein (GFAP), a type III intermediate filament, is a marker of mature astrocytes. The expression of GFAP gene is regulated by many transcription factors (TFs), mainly Janus kinase-2/signal transducer and activator of transcription 3 cascade and nuclear factor κ-light-chain-enhancer of activated B cell signaling. GFAP expression is also modulated by protein kinase and other signaling molecules that are elicited by neuronal activity and hormones. Abnormal expression of GFAP proteins occurs in neuroinflammation, neurodegeneration, brain edema-eliciting diseases, traumatic brain injury, psychiatric disorders and others. GFAP, mainly in α-isoform, is the major component of cytoskeleton and the scaffold of astrocytes, which is essential for the maintenance of astrocytic structure and shape. GFAP also has highly morphological plasticity because of its quick changes in assembling and polymerizing states in response to environmental challenges. This plasticity and its corresponding cellular morphological changes endow astrocytes the functions of physical barrier between adjacent neurons and stabilizer of extracellular environment. Moreover, GFAP colocalizes and even molecularly associates with many functional molecules. This feature allows GFAP to function as a platform for direct interactions between different molecules. Last, GFAP involves transportation and localization of other functional proteins and thus serves as a protein transport guide in astrocytes. This guiding role of GFAP involves an elastic retraction and extension cytoskeletal network that couples with GFAP reassembling, transporting, and membrane protein recycling machinery. This paper reviews our current understanding of the expression and functions of GFAP as well as their regulation.
Collapse
Affiliation(s)
- Dongyang Li
- Department of Physiology, Harbin Medical University, Harbin, China
| | - Xiaoyu Liu
- Department of Physiology, Harbin Medical University, Harbin, China
| | - Tianming Liu
- Department of Physiology, Harbin Medical University, Harbin, China
| | - Haitao Liu
- Department of Physiology, Harbin Medical University, Harbin, China
| | - Li Tong
- Department of Physiology, Harbin Medical University, Harbin, China
| | - Shuwei Jia
- Department of Physiology, Harbin Medical University, Harbin, China
| | - Yu-Feng Wang
- Department of Physiology, Harbin Medical University, Harbin, China
| |
Collapse
|
11
|
Wang P, Wang SC, Yang H, Lv C, Jia S, Liu X, Wang X, Meng D, Qin D, Zhu H, Wang YF. Therapeutic Potential of Oxytocin in Atherosclerotic Cardiovascular Disease: Mechanisms and Signaling Pathways. Front Neurosci 2019; 13:454. [PMID: 31178679 PMCID: PMC6537480 DOI: 10.3389/fnins.2019.00454] [Citation(s) in RCA: 49] [Impact Index Per Article: 9.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/14/2018] [Accepted: 04/23/2019] [Indexed: 12/12/2022] Open
Abstract
Coronary artery disease (CAD) is a major cardiovascular disease responsible for high morbidity and mortality worldwide. The major pathophysiological basis of CAD is atherosclerosis in association with varieties of immunometabolic disorders that can suppress oxytocin (OT) receptor (OTR) signaling in the cardiovascular system (CVS). By contrast, OT not only maintains cardiovascular integrity but also has the potential to suppress and even reverse atherosclerotic alterations and CAD. These protective effects of OT are associated with its protection of the heart and blood vessels from immunometabolic injuries and the resultant inflammation and apoptosis through both peripheral and central approaches. As a result, OT can decelerate the progression of atherosclerosis and facilitate the recovery of CVS from these injuries. At the cellular level, the protective effect of OT on CVS involves a broad array of OTR signaling events. These signals mainly belong to the reperfusion injury salvage kinase pathway that is composed of phosphatidylinositol 3-kinase-Akt-endothelial nitric oxide synthase cascades and extracellular signal-regulated protein kinase 1/2. Additionally, AMP-activated protein kinase, Ca2+/calmodulin-dependent protein kinase signaling and many others are also implicated in OTR signaling in the CVS protection. These signaling events interact coordinately at many levels to suppress the production of inflammatory cytokines and the activation of apoptotic pathways. A particular target of these signaling events is endoplasmic reticulum (ER) stress and mitochondrial oxidative stress that interact through mitochondria-associated ER membrane. In contrast to these protective effects and machineries, rare but serious cardiovascular disturbances were also reported in labor induction and animal studies including hypotension, reflexive tachycardia, coronary spasm or thrombosis and allergy. Here, we review our current understanding of the protective effect of OT against varieties of atherosclerotic etiologies as well as the approaches and underlying mechanisms of these effects. Moreover, potential cardiovascular disturbances following OT application are also discussed to avoid unwanted effects in clinical trials of OT usages.
Collapse
Affiliation(s)
- Ping Wang
- Department of Genetics, School of Basic Medical Sciences, Harbin Medical University, Harbin, China
| | - Stephani C Wang
- Department of Medicine, Albany Medical Center, Albany, NY, United States
| | - Haipeng Yang
- Department of Pediatrics, The Forth Affiliated Hospital, Harbin Medical University, Harbin, China
| | - Chunmei Lv
- Department of Physiology, School of Basic Medical Sciences, Harbin Medical University, Harbin, China
| | - Shuwei Jia
- Department of Physiology, School of Basic Medical Sciences, Harbin Medical University, Harbin, China
| | - Xiaoyu Liu
- Department of Physiology, School of Basic Medical Sciences, Harbin Medical University, Harbin, China
| | - Xiaoran Wang
- Department of Physiology, School of Basic Medical Sciences, Harbin Medical University, Harbin, China
| | - Dexin Meng
- Department of Physiology, Jiamusi University, Jiamusi, China
| | - Danian Qin
- Department of Physiology, Shantou University of Medical College, Shantou, China
| | - Hui Zhu
- Department of Physiology, School of Basic Medical Sciences, Harbin Medical University, Harbin, China
| | - Yu-Feng Wang
- Department of Physiology, School of Basic Medical Sciences, Harbin Medical University, Harbin, China
| |
Collapse
|
12
|
Wang P, Wang SC, Li D, Li T, Yang HP, Wang L, Wang YF, Parpura V. Role of Connexin 36 in Autoregulation of Oxytocin Neuronal Activity in Rat Supraoptic Nucleus. ASN Neuro 2019; 11:1759091419843762. [PMID: 31091986 PMCID: PMC6535915 DOI: 10.1177/1759091419843762] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/18/2018] [Revised: 02/10/2019] [Accepted: 02/26/2019] [Indexed: 12/24/2022] Open
Abstract
In the supraoptic nucleus (SON), the incidence of dye coupling among oxytocin (OT) neurons increases significantly in nursing mothers. However, the type(s) of connexin (Cx) involved is(are) unknown. In this study, we specifically investigated whether Cx36 plays a functional role in the coupling between OT neurons in the SON of lactating rats. In this brain region, Cx36 was mainly coimmunostained with vasopressin neurons in virgin female rats, whereas in lactating rats, Cx36 was primarily colocalized with OT neurons. In brain slices from lactating rats, application of quinine (0.1 mM), a selective blocker of Cx36, significantly reduced dye coupling among OT neurons as well as the discharge/firing frequency of spikes/action potentials and their amplitude, and transiently depolarized the membrane potential of OT neurons in whole-cell patch-clamp recordings. However, quinine significantly reduced the amplitude, but not frequency, of inhibitory postsynaptic currents in OT neurons; the duration of excitatory postsynaptic currents was reduced but not their frequency and amplitude. Furthermore, the excitatory effect of OT (1 pM) on OT neurons was significantly weakened and delayed by quinine, and burst firing was absent in the presence of this inhibitor. Lastly, Western blotting analysis revealed that the presence of combined, but not alone, quinine and OT significantly reduced the amount of Cx36 in the SON. Thus, Cx36-mediated junctional communication plays a crucial role in autoregulatory control of OT neuronal activity, likely by acting at the postsynaptic sites. The level of Cx36 is modulated by its own activity and the presence of OT.
Collapse
Affiliation(s)
- Ping Wang
- Department of Genetics, School of Basic Medical Sciences, Harbin Medical University, China
| | | | - Dongyang Li
- Department of Physiology, School of Basic Medical Sciences, Harbin Medical University, China
| | - Tong Li
- Department of Physiology, School of Basic Medical Sciences, Harbin Medical University, China
| | - Hai-Peng Yang
- The Fourth Affiliated Hospital, Harbin Medical University, China
| | - Liwei Wang
- The Fourth Affiliated Hospital, Harbin Medical University, China
| | - Yu-Feng Wang
- Department of Physiology, School of Basic Medical Sciences, Harbin Medical University, China
| | - Vladimir Parpura
- Department of Neurobiology, The University of Alabama at Birmingham, AL, USA
| |
Collapse
|
13
|
Lin YT, Hsu KS. Oxytocin receptor signaling in the hippocampus: Role in regulating neuronal excitability, network oscillatory activity, synaptic plasticity and social memory. Prog Neurobiol 2018; 171:1-14. [DOI: 10.1016/j.pneurobio.2018.10.003] [Citation(s) in RCA: 43] [Impact Index Per Article: 7.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/26/2018] [Revised: 08/28/2018] [Accepted: 10/20/2018] [Indexed: 12/23/2022]
|
14
|
Jurek B, Neumann ID. The Oxytocin Receptor: From Intracellular Signaling to Behavior. Physiol Rev 2018; 98:1805-1908. [DOI: 10.1152/physrev.00031.2017] [Citation(s) in RCA: 408] [Impact Index Per Article: 68.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/08/2023] Open
Abstract
The many facets of the oxytocin (OXT) system of the brain and periphery elicited nearly 25,000 publications since 1930 (see FIGURE 1 , as listed in PubMed), which revealed central roles for OXT and its receptor (OXTR) in reproduction, and social and emotional behaviors in animal and human studies focusing on mental and physical health and disease. In this review, we discuss the mechanisms of OXT expression and release, expression and binding of the OXTR in brain and periphery, OXTR-coupled signaling cascades, and their involvement in behavioral outcomes to assemble a comprehensive picture of the central and peripheral OXT system. Traditionally known for its role in milk let-down and uterine contraction during labor, OXT also has implications in physiological, and also behavioral, aspects of reproduction, such as sexual and maternal behaviors and pair bonding, but also anxiety, trust, sociability, food intake, or even drug abuse. The many facets of OXT are, on a molecular basis, brought about by a single receptor. The OXTR, a 7-transmembrane G protein-coupled receptor capable of binding to either Gαior Gαqproteins, activates a set of signaling cascades, such as the MAPK, PKC, PLC, or CaMK pathways, which converge on transcription factors like CREB or MEF-2. The cellular response to OXT includes regulation of neurite outgrowth, cellular viability, and increased survival. OXTergic projections in the brain represent anxiety and stress-regulating circuits connecting the paraventricular nucleus of the hypothalamus, amygdala, bed nucleus of the stria terminalis, or the medial prefrontal cortex. Which OXT-induced patterns finally alter the behavior of an animal or a human being is still poorly understood, and studying those OXTR-coupled signaling cascades is one initial step toward a better understanding of the molecular background of those behavioral effects.
Collapse
Affiliation(s)
- Benjamin Jurek
- Department of Behavioural and Molecular Neurobiology, Institute of Zoology, University of Regensburg, Regensburg, Germany
| | - Inga D. Neumann
- Department of Behavioural and Molecular Neurobiology, Institute of Zoology, University of Regensburg, Regensburg, Germany
| |
Collapse
|
15
|
Oxytocin inhibits head and neck squamous cell carcinoma cell migration by early growth response-1 upregulation. Anticancer Drugs 2017; 28:613-622. [PMID: 28452807 DOI: 10.1097/cad.0000000000000501] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/19/2023]
Abstract
The effect of oxytocin (OXT) on cancer invasion is controversial. Few studies have examined the effect of early growth response-1 (EGR1) on the invasion of head and neck squamous cell carcinoma (HNSCC). Here, we evaluated how EGR1 affects HNSCC cell migration through the molecular mechanism of OXT in exerting anti-invasion activity. Matrigel invasion and wound-healing assays were used to measure the in-vitro cell migration. The molecular mechanism of OXT was assessed by knockdown or overexpression of EGR1 in HNSCC cells. Three-dimensional (3-D) spheroids formation, followed by the image analysis for quantification was performed. OXT at 500 nmol/l increased mRNA and protein expression of E-cadherin without cytotoxicity. OXT upregulated mRNA and protein expression of EGR1 in 6 h. p53, phosphatase and tensin, and p21 expression was increased in an EGR1-dependent manner with OXT treatment. In addition, OXT significantly downregulated 3-D spheroids' formation according to spheroids' number and size. Our data showed that OXT downregulated HNSCC cell migration by EGR1 upregulation. OXT inhibited spheroids' formation of HNSCC cells under 3-D culture conditions.
Collapse
|
16
|
Wang P, Qin D, Wang YF. Oxytocin Rapidly Changes Astrocytic GFAP Plasticity by Differentially Modulating the Expressions of pERK 1/2 and Protein Kinase A. Front Mol Neurosci 2017; 10:262. [PMID: 28860967 PMCID: PMC5559427 DOI: 10.3389/fnmol.2017.00262] [Citation(s) in RCA: 21] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/01/2017] [Accepted: 07/31/2017] [Indexed: 12/23/2022] Open
Abstract
The importance of astrocytes to normal brain functions and neurological diseases has been extensively recognized; however, cellular mechanisms underlying functional and structural plasticities of astrocytes remain poorly understood. Oxytocin (OT) is a neuropeptide that can rapidly change astrocytic plasticity in association with lactation, as indicated in the expression of glial fibrillary acidic protein (GFAP) in the supraoptic nucleus (SON). Here, we used OT-evoked changes in GFAP expression in astrocytes of male rat SON as a model to explore the cellular mechanisms underlying GFAP plasticity. The results showed that OT significantly reduced the expression of GFAP filaments and proteins in SON astrocytes in brain slices. In lysates of the SON, OT receptors (OTRs) were co-immunoprecipitated with GFAP; vasopressin (VP), a neuropeptide structurally similar to OT, did not significantly change GFAP protein level; OT-evoked depolarization of astrocyte membrane potential was sensitive to a selective OTR antagonist (OTRA) but not to tetanus toxin, a blocker of synaptic transmission. The effects of OT on GFAP expression and on astrocyte uptake of Bauer-Peptide, an astrocyte-specific dye, were mimicked by isoproterenol (IPT; β-adrenoceptor agonist), U0126 or PD98059, inhibitors of extracellular signal-regulated protein kinase (ERK) 1/2 kinase and blocked by the OTRA or KT5720, a protein kinase A (PKA) inhibitor. The effect of OT on GFAP expressions and its association with these kinases were simulated by mSIRK, an activator of Gβγ subunits. Finally, suckling increased astrocytic expression of the catalytic subunit of PKA (cPKA) at astrocytic processes while increasing the molecular associations of GFAP with cPKA and phosphorylated ERK (pERK) 1/2. Upon the occurrence of the milk-ejection reflex, spatial co-localization of the cPKA with GFAP filaments further increased, which was accompanied with increased molecular association of GFAP with pERK 1/2 but not with cPKA. Thus, OT-elicited GFAP plasticity is achieved by sequential activation of ERK 1/2 and PKA via OTR signaling pathway in an antagonistic but coordinated manner.
Collapse
Affiliation(s)
- Ping Wang
- School of Basic Medical Sciences, Harbin Medical UniversityHarbin, China
| | - Danian Qin
- Department of Physiology, Shantou UniversityShantou, China
| | - Yu-Feng Wang
- School of Basic Medical Sciences, Harbin Medical UniversityHarbin, China
| |
Collapse
|
17
|
Costa B, Pini S, Baldwin DS, Silove D, Manicavasagar V, Abelli M, Coppedè F, Martini C. Oxytocin receptor and G-protein polymorphisms in patients with depression and separation anxiety. J Affect Disord 2017; 218:365-373. [PMID: 28499211 DOI: 10.1016/j.jad.2017.03.056] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/06/2016] [Revised: 03/16/2017] [Accepted: 03/26/2017] [Indexed: 10/19/2022]
Abstract
BACKGROUND The impact of combined variants of Oxytocin Receptor (OXTR) and G protein β3 subunit genes was investigated in relation to retrospective reports of childhood as well as contemporary adult separation anxiety (SA), based on evidence of a β/γ dimer-mediated signaling for OXTR. METHODS A case-control association study (225 healthy adults and 188 outpatients with depression) was performed to establish Risk-Combined Genotype (RCG) of the studied variants (OXTR rs53576 and the functional Gβ3 subunit rs5443). Current SA was evaluated by the ASA-27 and retrospective childhood symptoms by the SASI. GG genotype of OXTR rs53576 combined with T-carrier genotype of Gβ3 rs5443 represented the RCG. RESULTS Compared to non-RCG, those with RCG had significantly higher levels of childhood and adult SA. The RCG was significantly associated with childhood SA threshold score (OR=2.85, 90%CI: 1.08-7.50). Childhood SA was, in turn, strongly associated with a threshold SA score in adulthood (OR=15.58; 95% CI: 4.62-52.59). LIMITATIONS Although the overall sample size is sizable, comparisons among subgroups with specific combination of alleles are based on relatively small numbers. CONCLUSIONS Our study indicates that variations in OXTR and Gβ3 genes are specifically associated with presence and severity of SA in childhood and adulthood, but not with depression or anxiety in general. Because there is increasing interest in oxytocin in social behavior, the gene-SA associations identified have potential translational and clinical relevance.
Collapse
Affiliation(s)
- Barbara Costa
- Department of Pharmacy, University of Pisa, Pisa, Italy
| | - Stefano Pini
- Department of Clinical and Experimental Medicine, Section of Psychiatry, University of Pisa, Pisa, Italy.
| | - David S Baldwin
- Clinical and Experimental Sciences, University of Southampton Faculty of Medicine, Academic Centre, College Keep, 4-12 Terminus Terrace, Southampton SO14 3DT, United Kingdom
| | - Derrick Silove
- Psychiatry Research and Teaching Unit, School of Psychiatry, University of New South Wales, Sydney, Australia
| | | | - Marianna Abelli
- Department of Clinical and Experimental Medicine, Section of Psychiatry, University of Pisa, Pisa, Italy
| | - Fabio Coppedè
- Department of Translational Research and New Technologies in Medicine and Surgery, University of Pisa, Pisa, Italy
| | | |
Collapse
|
18
|
Kim SH, Bennett PR, Terzidou V. Advances in the role of oxytocin receptors in human parturition. Mol Cell Endocrinol 2017; 449:56-63. [PMID: 28119132 DOI: 10.1016/j.mce.2017.01.034] [Citation(s) in RCA: 37] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/08/2016] [Revised: 01/16/2017] [Accepted: 01/21/2017] [Indexed: 12/26/2022]
Abstract
Oxytocin (OT) is a neurohypophysial hormone which has been found to play a central role in the regulation of human parturition. The most established role of oxytocin/oxytocin receptor (OT/OTR) system in human parturition is the initiation of uterine contractions, however, recent evidence have demonstrated that it may have a more complex role including initiation of inflammation, regulation of miRNA expression, as well as mediation of other non-classical oxytocin actions via receptor crosstalk with other G protein-coupled receptors (GPCRs). In this review we highlight both established and newly emerging roles of OT/OTR system in human parturition and discuss the expanding potential for OTRs as pharmacological targets in the management of preterm labour.
Collapse
Affiliation(s)
- Sung Hye Kim
- Imperial College London, Parturition Research Group, Institute of Reproductive and Developmental Biology, Hammersmith Hospital Campus, Du Cane Road, East Acton, London W12 0NN, UK
| | - Phillip R Bennett
- Imperial College London, Parturition Research Group, Institute of Reproductive and Developmental Biology, Hammersmith Hospital Campus, Du Cane Road, East Acton, London W12 0NN, UK
| | - Vasso Terzidou
- Imperial College London, Parturition Research Group, Institute of Reproductive and Developmental Biology, Hammersmith Hospital Campus, Du Cane Road, East Acton, London W12 0NN, UK; Academic Department of Obstetrics & Gynaecology, Imperial College School of Medicine, Chelsea and Westminster Hospital, 369 Fulham Road, London SW10 9NH, UK.
| |
Collapse
|
19
|
York N, Halbach P, Chiu MA, Bird IM, Pillers DAM, Pattnaik BR. Oxytocin (OXT)-stimulated inhibition of Kir7.1 activity is through PIP 2-dependent Ca 2+ response of the oxytocin receptor in the retinal pigment epithelium in vitro. Cell Signal 2017; 37:93-102. [PMID: 28603013 DOI: 10.1016/j.cellsig.2017.06.005] [Citation(s) in RCA: 22] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/20/2017] [Revised: 05/28/2017] [Accepted: 06/05/2017] [Indexed: 01/26/2023]
Abstract
Oxytocin (OXT) is a neuropeptide that activates the oxytocin receptor (OXTR), a rhodopsin family G-protein coupled receptor. Our localization of OXTR to the retinal pigment epithelium (RPE), in close proximity to OXT in the adjacent photoreceptor neurons, leads us to propose that OXT plays an important role in RPE-retinal communication. An increase of RPE [Ca2+]i in response to OXT stimulation implies that the RPE may utilize oxytocinergic signaling as a mechanism by which it accomplishes some of its many roles. In this study, we used an established human RPE cell line, a HEK293 heterologous OXTR expression system, and pharmacological inhibitors of Ca2+ signaling to demonstrate that OXTR utilizes capacitative Ca2+ entry (CCE) mechanisms to sustain an increase in cytoplasmic Ca2+. These findings demonstrate how multiple functional outcomes of OXT-OXTR signaling could be integrated via a single pathway. In addition, the activated OXTR was able to inhibit the Kir7.1 channel, an important mediator of sub retinal waste transport and K+ homeostasis.
Collapse
Affiliation(s)
- Nathaniel York
- Endocrinology-Reproductive Physiology Program, The University of Wisconsin, Madison, WI 53715, United States; Division of Neonatology& Newborn Nursery, The University of Wisconsin, Madison, WI 53715, United States; Departments of Pediatrics, The University of Wisconsin, Madison, WI 53715, United States; The McPherson Eye Research Institute, The University of Wisconsin, Madison, WI 53715, United States
| | - Patrick Halbach
- Endocrinology-Reproductive Physiology Program, The University of Wisconsin, Madison, WI 53715, United States; Division of Neonatology& Newborn Nursery, The University of Wisconsin, Madison, WI 53715, United States; Departments of Pediatrics, The University of Wisconsin, Madison, WI 53715, United States; The McPherson Eye Research Institute, The University of Wisconsin, Madison, WI 53715, United States
| | - Michelle A Chiu
- Division of Neonatology& Newborn Nursery, The University of Wisconsin, Madison, WI 53715, United States; Departments of Pediatrics, The University of Wisconsin, Madison, WI 53715, United States; The McPherson Eye Research Institute, The University of Wisconsin, Madison, WI 53715, United States
| | - Ian M Bird
- Endocrinology-Reproductive Physiology Program, The University of Wisconsin, Madison, WI 53715, United States; Obstetrics & Gynecology, The University of Wisconsin, Madison, WI 53715, United States
| | - De-Ann M Pillers
- Division of Neonatology& Newborn Nursery, The University of Wisconsin, Madison, WI 53715, United States; Departments of Pediatrics, The University of Wisconsin, Madison, WI 53715, United States; Medical Genetics, The University of Wisconsin, Madison, WI 53715, United States; The McPherson Eye Research Institute, The University of Wisconsin, Madison, WI 53715, United States
| | - Bikash R Pattnaik
- Endocrinology-Reproductive Physiology Program, The University of Wisconsin, Madison, WI 53715, United States; Division of Neonatology& Newborn Nursery, The University of Wisconsin, Madison, WI 53715, United States; Departments of Pediatrics, The University of Wisconsin, Madison, WI 53715, United States; Ophthalmology &Visual Sciences, The University of Wisconsin, Madison, WI 53715, United States; The McPherson Eye Research Institute, The University of Wisconsin, Madison, WI 53715, United States.
| |
Collapse
|
20
|
Zatkova M, Reichova A, Bacova Z, Strbak V, Kiss A, Bakos J. Neurite Outgrowth Stimulated by Oxytocin Is Modulated by Inhibition of the Calcium Voltage-Gated Channels. Cell Mol Neurobiol 2017; 38:371-378. [DOI: 10.1007/s10571-017-0503-3] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/31/2017] [Accepted: 05/06/2017] [Indexed: 11/29/2022]
|
21
|
Oxytocin, a main breastfeeding hormone, prevents hypertension acquired in utero: A therapeutics preview. Biochim Biophys Acta Gen Subj 2016; 1861:3071-3084. [PMID: 27658996 DOI: 10.1016/j.bbagen.2016.09.020] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/13/2016] [Revised: 08/29/2016] [Accepted: 09/16/2016] [Indexed: 02/07/2023]
Abstract
Hypertension is a major risk factor for ischemic heart disease and stroke, leading causes of morbidity and death worldwide. Intrauterine growth restriction (IUGR), caused by an excess of glucocorticoid exposure to the fetus, produces an imbalance in oxidative stress altering many biochemical and epigenetic gene transcription processes exposing the fetus and neonate to the 'thrifty' phenotype and pervasive polymorphisms appearance damaging health, cognitive, and behavioral processes in later life. OT is a major regulator of oxidative stress radicals that plays a major role in neonatal maturation of the central nervous system and many peripheral tissues expressing oxytocin/oxytocin-receptor (OT/OTR) system in the early postnatal period. OT and OTR are damaged by IUGR and early stress. This review highlights the fact that hypertension is likely to be a legacy of preterm birth due to IUGR and failure to meet nutritional needs in early infancy when fed formula instead of breastfeeding or human milk.
Collapse
|
22
|
Halbach P, Pillers DAM, York N, Asuma MP, Chiu MA, Luo W, Tokarz S, Bird IM, Pattnaik BR. Oxytocin expression and function in the posterior retina: a novel signaling pathway. Invest Ophthalmol Vis Sci 2015; 56:751-60. [PMID: 25593022 DOI: 10.1167/iovs.14-15646] [Citation(s) in RCA: 21] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022] Open
Abstract
PURPOSE Oxytocin (OXT) is recognized as an ubiquitously acting nonapeptide hormone that is involved in processes ranging from parturition to neural development. Its effects are mediated by cell signaling that occurs as a result of oxytocin receptor (OXTR) activation. We sought to determine whether the OXT-OXTR signaling pathway is also expressed within the retina. METHODS Immunohistochemistry using cell-specific markers was used to localize OXT within the rhesus retina. Reverse transcriptase PCR and immunohistochemistry were used to assess the expression of OXTR in both human and rhesus retina. Single-cell RT-PCR and Western blot analyses were used to determine the expression of OXTR in cultured human fetal RPE (hfRPE) cells. Human fetal RPE cells loaded with FURA-2 AM were studied by ratiometric Ca(2+) imaging to assess transient mobilization of intracellular Ca(2+) ([Ca(2+)]i). RESULTS Oxytocin was expressed in the cone photoreceptor extracellular matrix of the rhesus retina. Oxytocin mRNA and protein were expressed in the human and rhesus RPE. Oxytocin mRNA and protein expression were observed in cultured hfRPE cells, and exposure of these cells to 100 nM OXT induced a transient 79 ± 1.5 nM increase of [Ca(2+)]i. CONCLUSIONS Oxytocin and OXTR are present in the posterior retina, and OXT induces an increase in hfRPE [Ca(2+)]i. These results suggest that the OXT-OXTR signaling pathway is active in the retina. We propose that OXT activation of the OXTR occurs in the posterior retina and that this may serve as a paracrine signaling pathway that contributes to communication between the cone photoreceptor and the RPE.
Collapse
Affiliation(s)
- Patrick Halbach
- Division of Neonatology, Department of Pediatrics, University of Wisconsin, Madison, Wisconsin, United States The Endocrinology-Reproductive Physiology Program, University of Wisconsin, Madison, Wisconsin, United States
| | - De-Ann M Pillers
- Division of Neonatology, Department of Pediatrics, University of Wisconsin, Madison, Wisconsin, United States McPherson Eye Research Institute, University of Wisconsin, Madison, Wisconsin, United States
| | - Nathaniel York
- Division of Neonatology, Department of Pediatrics, University of Wisconsin, Madison, Wisconsin, United States The Endocrinology-Reproductive Physiology Program, University of Wisconsin, Madison, Wisconsin, United States
| | - Matti P Asuma
- Division of Neonatology, Department of Pediatrics, University of Wisconsin, Madison, Wisconsin, United States
| | - Michelle A Chiu
- Division of Neonatology, Department of Pediatrics, University of Wisconsin, Madison, Wisconsin, United States
| | - Wenxiang Luo
- Division of Neonatology, Department of Pediatrics, University of Wisconsin, Madison, Wisconsin, United States
| | - Sara Tokarz
- Division of Neonatology, Department of Pediatrics, University of Wisconsin, Madison, Wisconsin, United States
| | - Ian M Bird
- Division of Neonatology, Department of Pediatrics, University of Wisconsin, Madison, Wisconsin, United States The Endocrinology-Reproductive Physiology Program, University of Wisconsin, Madison, Wisconsin, United States Departments of Obstetrics/Gynecology, University of Wisconsin, Madison, Wisconsin, United States
| | - Bikash R Pattnaik
- Division of Neonatology, Department of Pediatrics, University of Wisconsin, Madison, Wisconsin, United States Department of Ophthalmology and Visual Sciences, University of Wisconsin, Madison, Wisconsin, United States
| |
Collapse
|
23
|
Vargas-Martínez F, Uvnäs-Moberg K, Petersson M, Olausson HA, Jiménez-Estrada I. Neuropeptides as neuroprotective agents: Oxytocin a forefront developmental player in the mammalian brain. Prog Neurobiol 2014; 123:37-78. [DOI: 10.1016/j.pneurobio.2014.10.001] [Citation(s) in RCA: 31] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/30/2014] [Accepted: 10/06/2014] [Indexed: 02/07/2023]
|
24
|
Wouters E, Hudson CA, McArdle CA, Bernal AL. Central role for protein kinase C in oxytocin and epidermal growth factor stimulated cyclooxygenase 2 expression in human myometrial cells. BMC Res Notes 2014; 7:357. [PMID: 24916153 PMCID: PMC4057899 DOI: 10.1186/1756-0500-7-357] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/04/2013] [Accepted: 06/03/2014] [Indexed: 02/02/2023] Open
Abstract
BACKGROUND Prostaglandins are important mediators of uterine contractility and cervical ripening during labour. Cyclooxygenase-2 (COX-2), also known as prostaglandin-endoperoxide synthase 2, is a rate limiting enzyme involved in the conversion of arachidonic acid into prostaglandins at parturition. In this paper, the pathways underlying agonist-induced cyclooxygenase-2 expression in human myometrial cells were studied. RESULTS Myometrial cells were stimulated with different agonists: oxytocin (OXT), epidermal growth factor (EGF), interleukin-1β (IL1β), and phorbol-12-myristate-13-acetate (PMA) alone and in the presence of specific signalling pathway inhibitors. The nuclear factor kappa-light-chain-enhancer of activated B cells (NFKB) pathway was inhibited by means of the IKK-2 inhibitor TPCA-1. Signalling through extracellular signal-regulated kinases (ERK) was inhibited using the MEK1/2 inhibitor PD-184352. Bisindolylmaleimide-I was used to inhibit protein kinase C (PKC) signalling. COX-2 expression and ERK phosphorylation were measured using immunoblotting.OXT induced COX-2 expression by activating PKC and ERK. EGF increased COX-2 expression via stimulation of PKC, ERK and NFKB. As expected, the pro-inflammatory cytokine IL1β induced COX-2 expression by activating PKC- and NFKB-dependent pathways. Stimulation of PKC directly with PMA provoked strong COX-2 expression. CONCLUSIONS PKC plays a central role in OXT and EGF induced COX-2 expression in human myometrial cells. However, other pathways, notably ERK and NFKB are also involved to an extent which depends on the type of agonist used.
Collapse
Affiliation(s)
| | | | | | - Andrés López Bernal
- University of Bristol, School of Clinical Sciences (Obstetrics and Gynaecology), Dorothy Hodgkin Building, Whitson Street, Bristol BS1 3NY, UK.
| |
Collapse
|
25
|
Mamrut S, Harony H, Sood R, Shahar-Gold H, Gainer H, Shi YJ, Barki-Harrington L, Wagner S. DNA methylation of specific CpG sites in the promoter region regulates the transcription of the mouse oxytocin receptor. PLoS One 2013; 8:e56869. [PMID: 23441222 PMCID: PMC3575498 DOI: 10.1371/journal.pone.0056869] [Citation(s) in RCA: 81] [Impact Index Per Article: 7.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/30/2012] [Accepted: 01/15/2013] [Indexed: 01/15/2023] Open
Abstract
Oxytocin is a peptide hormone, well known for its role in labor and suckling, and most recently for its involvement in mammalian social behavior. All central and peripheral actions of oxytocin are mediated through the oxytocin receptor, which is the product of a single gene. Transcription of the oxytocin receptor is subject to regulation by gonadal steroid hormones, and is profoundly elevated in the uterus and mammary glands during parturition. DNA methylation is a major epigenetic mechanism that regulates gene transcription, and has been linked to reduced expression of the oxytocin receptor in individuals with autism. Here, we hypothesized that transcription of the mouse oxytocin receptor is regulated by DNA methylation of specific sites in its promoter, in a tissue-specific manner. Hypothalamus-derived GT1-7, and mammary-derived 4T1 murine cell lines displayed negative correlations between oxytocin receptor transcription and methylation of the gene promoter, and demethylation caused a significant enhancement of oxytocin receptor transcription in 4T1 cells. Using a reporter gene assay, we showed that methylation of specific sites in the gene promoter, including an estrogen response element, significantly inhibits transcription. Furthermore, methylation of the oxytocin receptor promoter was found to be differentially correlated with oxytocin receptor expression in mammary glands and the uterus of virgin and post-partum mice, suggesting that it plays a distinct role in oxytocin receptor transcription among tissues and under different physiological conditions. Together, these results support the hypothesis that the expression of the mouse oxytocin receptor gene is epigenetically regulated by DNA methylation of its promoter.
Collapse
Affiliation(s)
- Shimrat Mamrut
- Department of Neurobiology, University of Haifa, Haifa, Israel
| | - Hala Harony
- Department of Neurobiology, University of Haifa, Haifa, Israel
| | - Rapita Sood
- Department of Human Biology, University of Haifa, Haifa, Israel
| | | | - Harold Gainer
- Laboratory of Neurochemistry, National Institute of Neurological Disorders and Stroke, National Institutes of Health, Bethesda, Maryland, United States of America
| | - Yi-Jun Shi
- Laboratory of Neurochemistry, National Institute of Neurological Disorders and Stroke, National Institutes of Health, Bethesda, Maryland, United States of America
| | | | - Shlomo Wagner
- Department of Neurobiology, University of Haifa, Haifa, Israel
- * E-mail:
| |
Collapse
|
26
|
Oxytocin promotes long-term potentiation by enhancing epidermal growth factor receptor-mediated local translation of protein kinase Mζ. J Neurosci 2013; 32:15476-88. [PMID: 23115185 DOI: 10.1523/jneurosci.2429-12.2012] [Citation(s) in RCA: 58] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/23/2023] Open
Abstract
In addition to triggering the birthing process and milk release, the hypothalamic neuropeptide oxytocin (OXT) plays an important role in the regulation of complex social cognition and behavior. Previous work has shown that OXT can regulate hippocampal synaptic plasticity and improve hippocampus-dependent cognitive functions in the female mice, but the underlying mechanisms remain largely unclear. Here, we demonstrate that OXT promotes the maintenance of long-term potentiation (LTP) induced by one train of tetanic stimulation (TS) in the CA1 region of hippocampal slices from both nulliparous female and male rats through a previously unknown mechanism involving OXT receptor (OXTR)-dependent and epidermal growth factor receptor (EGFR)-mediated local translation of an atypical protein kinase C isoform, protein kinase Mζ (PKMζ), in dendrites. Using pharmacological and biochemical approaches, we show that both the conventional OXTR-associated signaling pathway (G(q/11)-coupled phospholipase C) and the transactivated EGFR downstream signaling pathways (phosphatidylinositol 3 kinase and extracellular signal-regulated kinase 1/2) are involved in the regulation of OXT. In addition, OXT stimulates local dendritic PKMζ mRNA translation via activation of a mammalian target of rapamycin-regulated mechanism. Furthermore, blockade of OXTR results in a modest decrease in the ability to maintain late-phase LTP induced by three trains of TS. These results reveal a novel OXTR-to-EGFR communication to regulate the new synthesis of PKMζ, which functions to promote the maintenance of LTP at hippocampal CA1 synapses.
Collapse
|
27
|
Jurek B, Slattery DA, Maloumby R, Hillerer K, Koszinowski S, Neumann ID, van den Burg EH. Differential contribution of hypothalamic MAPK activity to anxiety-like behaviour in virgin and lactating rats. PLoS One 2012; 7:e37060. [PMID: 22615888 PMCID: PMC3355176 DOI: 10.1371/journal.pone.0037060] [Citation(s) in RCA: 65] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/26/2012] [Accepted: 04/12/2012] [Indexed: 12/18/2022] Open
Abstract
The c-Raf – MEK1/2 – ERK1/2 mitogen-activated protein kinase (MAPK) intracellular signalling cascade in neurons plays important roles in the control of a variety of behaviours, including social behaviours and anxiety. These roles partially overlap with those described for oxytocin (OXT), and it has been shown that OXT activates the MAPK pathway in the hypothalamus (of male), and hippocampus (of female) rats. Here, by combining behavioural (light/dark box) and biochemical analyses (western blotting), we tested two hypotheses: (i) that OXT is anxiolytic within the hypothalamus of females, and (ii) that this effect, as well as that of lactation-associated anxiolysis, depends on the recruitment of the MAPK pathway. We found that, when injected bilaterally into the hypothalamic paraventricular nucleus (PVN), OXT decreased anxiety-like behaviour in virgins, and that this effect depended on phosphorylation of MEK1/2. MAPK pathway activation in lactation was evident by high phosphorylated (p) MEK1/2 levels, and nuclear translocation of ERK1. The high pMEK1/2 levels were necessary for the anxiolytic phenotype typically observed during lactation. Interestingly, exogenous OXT in lactating rats reduced pMEK1/2 levels without a concomitant effect on anxiety, indicating that OXT receptor activation can lead to recruitment of additional intracellular pathways to modulate MEK activity. Still other pathways could include MEK, but without subsequent activation of ERK, as we did not observe any increase in OXT-induced ERK phosphorylation. Together the results demonstrate that the MAPK pathway, especially MEK1/2, is critically involved in the regulation of anxiety-like behaviour in female rats.
Collapse
Affiliation(s)
- Benjamin Jurek
- Department of Behavioural and Molecular Neurobiology, University of Regensburg, Regensburg, Germany
| | - David A. Slattery
- Department of Behavioural and Molecular Neurobiology, University of Regensburg, Regensburg, Germany
| | - Rodrigue Maloumby
- Department of Behavioural and Molecular Neurobiology, University of Regensburg, Regensburg, Germany
| | - Katharina Hillerer
- Department of Behavioural and Molecular Neurobiology, University of Regensburg, Regensburg, Germany
| | - Sophie Koszinowski
- Department of Behavioural and Molecular Neurobiology, University of Regensburg, Regensburg, Germany
| | - Inga D. Neumann
- Department of Behavioural and Molecular Neurobiology, University of Regensburg, Regensburg, Germany
- * E-mail: Inga
| | - Erwin H. van den Burg
- Department of Behavioural and Molecular Neurobiology, University of Regensburg, Regensburg, Germany
| |
Collapse
|
28
|
Functional interactions between the oxytocin receptor and the β2-adrenergic receptor: implications for ERK1/2 activation in human myometrial cells. Cell Signal 2011; 24:333-41. [PMID: 21964067 DOI: 10.1016/j.cellsig.2011.09.019] [Citation(s) in RCA: 31] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/09/2011] [Revised: 09/09/2011] [Accepted: 09/11/2011] [Indexed: 01/05/2023]
Abstract
The Gq-coupled oxytocin receptor (OTR) and the Gs-coupled β(2)-adrenergic receptor (β(2)AR) are both expressed in myometrial cells and mediate uterine contraction and relaxation, respectively. The two receptors represent important pharmacological targets as OTR antagonists and β(2)AR agonists are used to control pre-term uterine contractions. Despite their physiologically antagonistic effects, both receptors activate the MAP kinases ERK1/2, which has been implicated in uterine contraction and the onset of labor. To determine the signalling pathways involved in mediating the ERK1/2 response, we assessed the effect of blockers of specific G protein-associated pathways. In human myometrial hTERT-C3 cells, inhibition of Gαi as well as inhibition of the Gαq/PKC pathway led to a reduction of both OTR- and β(2)AR-mediated ERK1/2 activation. The involvement of Gαq/PKC in β(2)AR-mediated ERK1/2 induction was unexpected. To test whether the emergence of this novel signalling mechanism was dependent on OTR expression in the same cell, we conducted experiments in HEK 293 cells that were transfected with the β(2)AR alone or co-transfected with the OTR. Using this approach, we found that β(2)AR-mediated ERK1/2 responses became sensitive to PKC inhibition only in cells co-transfected with the OTR. Inhibitor studies indicated the involvement of an atypical PKC isoform in this process. We confirmed the specific involvement of PKCζ in this pathway by assessing PKCζ translocation to the cell membrane. Consistent with our inhibitor studies, we found that β(2)AR-mediated PKCζ translocation was dependent on co-expression of OTR. The present demonstration of a novel β(2)AR-coupled signalling pathway that is dependent on OTR co-expression is suggestive of a molecular interaction between the two receptors.
Collapse
|
29
|
Brighton PJ, Rana S, Challiss RJ, Konje JC, Willets JM. Arrestins differentially regulate histamine- and oxytocin-evoked phospholipase C and mitogen-activated protein kinase signalling in myometrial cells. Br J Pharmacol 2011; 162:1603-17. [PMID: 21175586 DOI: 10.1111/j.1476-5381.2010.01173.x] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/27/2022] Open
Abstract
BACKGROUND AND PURPOSE The uterotonins oxytocin and histamine, mediate contractile signals through specific G protein-coupled receptors, a process which is tightly controlled during gestation to prevent preterm labour. We previously identified G protein-coupled receptor kinase (GRK)2 and GRK6 as respective cardinal negative regulators of histamine H(1) and oxytocin receptor signalling. GRK-mediated phosphorylation promotes arrestin recruitment, not only desensitizing receptors but activating an increasing number of diverse signalling pathways. Here we investigate potential roles that arrestins play in the regulation of myometrial oxytocin/histamine H(1) receptor signalling. EXPERIMENTAL APPROACH Endogenous arrestins2 and 3 were specifically depleted using RNA-interference in a human myometrial cell line and the consequences of this for G protein-coupled receptor-mediated signalling were assessed using Ca(2+) /inositol 1,4,5-trisphophate imaging and standard mitogen-activated protein kinase (MAPK) assays. KEY RESULTS Depletion of arrestin3, but not arrestin2 enhanced and prolonged H(1) receptor-stimulated Ca(2+) responses, whilst depletion of either arrestin increased oxytocin receptor responses. Arrestin3 depletion decreased H(1) receptor desensitization, whilst removal of either arrestin isoform was equally effective in preventing oxytocin receptor desensitization. Following arrestin3 depletion oxytocin-induced phospho-extracellular signal-regulated kinase1/2 signals were diminished and histamine-stimulated signals virtually absent, whereas depletion of arrestin2 augmented extracellular signal-regulated kinase1/2 responses to each agonist. Conversely, depletion of arrestin3 enhanced p38 signals to each agonist, whilst arrestin2 suppression increased oxytocin-, but not histamine-induced p38 MAPK responses. CONCLUSIONS AND IMPLICATIONS Arrestin proteins are key regulators of H(1) and oxytocin receptor desensitization, and play integral roles mediating uterotonin-stimulated MAPK-signalling. These data provide insights into the in situ regulation of these receptor subtypes and may inform pathophysiological functioning in preterm labour.
Collapse
Affiliation(s)
- Paul J Brighton
- Endocannabinoid Research Group, Reproductive Sciences Section, Department of Cancer Studies and Molecular Medicine, University of Leicester, Leicester Royal Infirmary, Leicester, UK
| | | | | | | | | |
Collapse
|
30
|
van den Burg EH, Neumann ID. Bridging the gap between GPCR activation and behaviour: oxytocin and prolactin signalling in the hypothalamus. J Mol Neurosci 2010; 43:200-8. [PMID: 20865346 DOI: 10.1007/s12031-010-9452-8] [Citation(s) in RCA: 34] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/23/2010] [Accepted: 09/13/2010] [Indexed: 01/06/2023]
Abstract
Neuropeptides of the brain are important neuromodulators, controlling behaviour and physiology. They signal through G protein-coupled receptors (GPCR) that couple to complex intracellular signalling pathways. These signalling networks integrate information from multiple sources, resulting in appropriate physiological and behavioural responses to environmental and internal cues. This paper will focus on the neuropeptides oxytocin and prolactin with respect to (1) the regulation of neuroendocrine stress responses and anxiety, and (2) the receptor-mediated molecular mechanisms underlying these actions of the neuropeptides. Besides its significant reproductive functions when released into the bloodstream, brain oxytocin reduces the activity of the hypothalamo-pituitary-adrenal (HPA) axis as well as anxiety-related behaviour in male and female rats. Oxytocin mediates its anxiolytic effect, at least in part, via binding to its GPCR in the hypothalamic paraventricular nucleus, followed by transactivation of the epidermal growth factor receptor, and subsequent activation of a MEK-extracellular signal-regulated kinase (ERK) MAP kinase pathway. Prolactin, by binding to its GPCR receptors, of which there are short and long forms, also activates ERK, and this is necessary for the control of the expression of corticotrophin-releasing hormone-an important regulator of the HPA axis. Liganded oxytocin and prolactin may also recruit other signalling pathways, but how these pathways contribute to the observed behavioural and physiological effects remains to be established. GPCR-mediated oxytocin and prolactin neuronal signalling are illustrative of the complexity of GPCR-activated regulation of appropriate neuroendocrine and behavioural responses to environmental and physiological demands.
Collapse
Affiliation(s)
- Erwin H van den Burg
- Behavioural and Molecular Neuroendocrinology, Institute of Zoology, University of Regensburg, 93053 Regensburg, Germany.
| | | |
Collapse
|
31
|
Zhong M, Boseman ML, Millena AC, Khan SA. Oxytocin induces the migration of prostate cancer cells: involvement of the Gi-coupled signaling pathway. Mol Cancer Res 2010; 8:1164-72. [PMID: 20663860 DOI: 10.1158/1541-7786.mcr-09-0329] [Citation(s) in RCA: 43] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022]
Abstract
Expression of genes that encode oxytocin (OXT) and vasopressin (AVP) and their cognate receptors in normal and diseased prostates are only partially characterized. Reverse transcription and PCR were used to examine the expression of these genes in normal prostate epithelial and stromal cell lines, k-ras-transformed prostate epithelial cell lines, and in four prostate cancer cell lines. Secreted and cell-associated OXT peptide was measured by an enzyme immunoassay. OXT and its receptor (OXTR) were expressed in all eight prostate cell lines. Cell-associated OXT peptide was also found in all prostate epithelial cell lines except in DU145 cells. Neither AVP nor its cognate receptors (V1a receptor and V2 receptor) were expressed in any prostate cell line examined. These data point to the OXTR as the primary target of OXT and AVP, and suggest that OXT might be an autocrine/paracrine regulator in human prostate. We found that OXT induces the migration of PC3 and PC3M, but not DU145 prostate cancer cells. The effect of OXT is distinct from the epidermal growth factor (EGF)-induced migration of prostate cancer cells, in which ERK1/2 and EGF receptor kinase activities were required. When cells were pretreated with pertussis toxin, the effect of OXT, but not EGF, on cell migration was abolished. Pretreatment with the cyclic AMP analogue, 8-Br-cAMP, did not affect OXT-induced cell migration, which eliminated the nonspecific effect of pertussis toxin. We conclude that a Gi-dependent mechanism is involved in OXTR-mediated migration of prostate cancer cells, and indicates a role for OXTR in prostate cancer metastasis.
Collapse
Affiliation(s)
- Miao Zhong
- Center for Cancer Research and Therapeutic Development, Clark Atlanta University, Atlanta, GA 30314, USA
| | | | | | | |
Collapse
|
32
|
Krishnaswamy N, Lacroix-Pepin N, Chapdelaine P, Taniguchi H, Kauffenstein G, Chakravarti A, Danyod G, Fortier MA. Epidermal growth factor receptor is an obligatory intermediate for oxytocin-induced cyclooxygenase 2 expression and prostaglandin F2 alpha production in bovine endometrial epithelial cells. Endocrinology 2010; 151:1367-74. [PMID: 20080869 DOI: 10.1210/en.2009-1304] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
Abstract
Oxytocin (OT) triggers the luteolytic pulses of prostaglandin F(2 alpha) (PGF(2 alpha)) from the endometrial epithelial cells in ruminants. We have proposed that the embryonic signal interferon-tau exerts its antiluteolytic effect by disrupting the OT signaling axis. Accordingly, we have attempted to define the signaling pathway of OT-induced PGF(2 alpha) production in the bovine endometrium using our newly characterized epithelial cell line (bEEL). OT receptor was coupled to the classical G alpha(q) pathway as evidenced by calcium release and activation of phospholipase C. Similarly, OT-induced PGF(2 alpha) production was mediated through the canonical ERK1/2 pathway. Because of the importance of receptor and nonreceptor tyrosine kinases in G protein-coupled receptor signaling, we studied the role of epidermal growth factor receptor (EGFR), c-Src, and phosphoinositide 3-kinase (PI3K) on OT-induced PGF(2 alpha) production in association with cyclooxygenase 2 (COX2) expression and ERK1/2 and Akt phosphorylation. The EGFR inhibitor AG1478 (10 microm) nearly abolished basal and OT-induced PGF(2 alpha) production and down-regulated COX2 expression and ERK1/2 phosphorylation. Because the transactivated EGFR can serve as a ligand for the signaling proteins with Src homology 2 (SH2) domain, we hypothesized a role for c-Src and PI3K in OT-induced PGF(2 alpha) production. Inhibitors of c-Src (PP2, 10 microm) and PI3K (LY294002, 25 microm) produced a significant decrease in OT-induced PGF(2 alpha) production and reduced COX2 expression. Also, PP2, but not LY294002, decreased OT-induced ERK1/2 phosphorylation. Because LY294002 did not affect ERK1/2 phosphorylation, but inhibited PGF(2 alpha) production and down-regulated COX2 expression, it is likely that the Akt pathway is also involved in PGF(2 alpha) production. Thus, EGFR may simultaneously activate c-Src and PI3K to amplify the OT signaling to increase the output of PGF(2 alpha) in bEEL cells.
Collapse
Affiliation(s)
- Narayanan Krishnaswamy
- Unité d'Ontogénie et Reproduction, Centre Hospitalier Universitaire de Québec, Centre Hospitalier de l'Université Laval, Université Laval, Québec QC G1V 4G2 Canada
| | | | | | | | | | | | | | | |
Collapse
|
33
|
Zhang Y, Kwon SH, Vogel WK, Filtz TM. PI(3,4,5)P3 potentiates phospholipase C-beta activity. J Recept Signal Transduct Res 2009; 29:52-62. [PMID: 19519170 DOI: 10.1080/10799890902729449] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/20/2022]
Abstract
Phospholipase C-beta (PLC-beta) isozymes are key effectors in G protein-coupled signaling pathways. Previously, we showed that PLC-beta1 and PLC-beta3 bound immobilized PIP(3). In this study, PIP(3) was found to potentiate Ca(2+)-stimulated PLC-beta activities using an in vitro reconstitution assay. LY294002, a specific PI 3-kinase inhibitor, significantly inhibited 10 min of agonist-stimulated total IP accumulation. Both LY294002 and wortmannin inhibited 90 sec of agonist-stimulated IP(3) accumulation in intact cells. Moreover, transfected p110CAAX, a constitutively activated PI 3-kinase catalytic subunit, increased 90 sec of oxytocin-stimulated IP(3) accumulation. Receptor-ligand binding assays indicated that LY294002 did not affect G protein-coupled receptors directly, suggesting a physiological role for PIP(3) in directly potentiating PLC-beta activity. When coexpressed with p110CAAX, fluorescence-tagged PLC-beta3 was increasingly localized to the plasma membrane. Additional observations suggest that the PH domain of PLC-beta is not important for p110CAAX-induced membrane association.
Collapse
Affiliation(s)
- Yong Zhang
- Department of Pharmaceutical Sciences, Oregon State University, Corvallis, OR 97331, USA
| | | | | | | |
Collapse
|
34
|
Youssef RE, Ledingham MA, Bollapragada SS, O'Gorman N, Jordan F, Young A, Norman JE. The Role of Toll-Like Receptors (TLR-2 and -4) and Triggering Receptor Expressed on Myeloid Cells 1 (TREM-1) in Human Term and Preterm Labor. Reprod Sci 2009; 16:843-56. [PMID: 19564644 DOI: 10.1177/1933719109336621] [Citation(s) in RCA: 50] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/18/2023]
Affiliation(s)
| | | | - Shrikant S. Bollapragada
- Reproductive & Maternal Medicine, University of Glasgow, Third Floor, Queen Elizabeth Building, Glasgow Royal Infirmary, United Kingdom
| | - Neil O'Gorman
- Reproductive & Maternal Medicine, University of Glasgow, Third Floor, Queen Elizabeth Building, Glasgow Royal Infirmary, United Kingdom
| | - Fiona Jordan
- Reproductive & Maternal Medicine, University of Glasgow, Third Floor, Queen Elizabeth Building, Glasgow Royal Infirmary, United Kingdom
| | - Anne Young
- Reproductive & Maternal Medicine, University of Glasgow, Third Floor, Queen Elizabeth Building, Glasgow Royal Infirmary, United Kingdom
| | - Jane E. Norman
- University of Edinburgh Centre for Reproductive Biology, The Queen's Medical Research Institute, Edinburgh, United Kingdom
| |
Collapse
|
35
|
Szeto A, Nation DA, Mendez AJ, Dominguez-Bendala J, Brooks LG, Schneiderman N, McCabe PM. Oxytocin attenuates NADPH-dependent superoxide activity and IL-6 secretion in macrophages and vascular cells. Am J Physiol Endocrinol Metab 2008; 295:E1495-501. [PMID: 18940936 PMCID: PMC2603556 DOI: 10.1152/ajpendo.90718.2008] [Citation(s) in RCA: 140] [Impact Index Per Article: 8.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/11/2023]
Abstract
Oxytocin is synthesized and released in the heart and vasculature, tissues that also express oxytocin receptors. Although it has been established this intrinsic cardiovascular oxytocin system is important in normal homeostatic cardiac and vascular regulation, a role for this system in cardiovascular pathophysiology has not been investigated. The current study examined the influence of oxytocin on mechanisms in atherogenesis, oxidative stress, and inflammation in cultured human vascular cells, THP-1 monocytes, and macrophages. Oxytocin receptor protein and mRNA expression, NADPH-dependent superoxide activity, and interleukin-6 secretion were measured. Results demonstrated oxytocin receptor protein and mRNA in THP-1 monocytes and macrophages. Incubation of cells at physiological levels of oxytocin significantly decreased basal and stimulated NADPH-dependent superoxide activity in vascular cells, monocytes, and macrophages by 24-48%. Oxytocin also attenuated interleukin-6 secretion from stimulated THP-1 macrophages and endothelial cells by 56 and 26%, respectively. These findings suggest that oxytocin attenuates vascular oxidative stress and inflammation, two important pathophysiological processes in atherosclerosis. The fact that oxytocin receptors are found in monocytes and macrophages, and oxytocin decreases both superoxide production and release of a proinflammatory cytokine from these cells, suggests a potentially larger role for oxytocin in the attenuation of disease.
Collapse
Affiliation(s)
- Angela Szeto
- Dept. of Psychology, Univ. of Miami, Coral Gables, FL 33124, USA
| | | | | | | | | | | | | |
Collapse
|
36
|
Blume A, Bosch OJ, Miklos S, Torner L, Wales L, Waldherr M, Neumann ID. Oxytocin reduces anxiety via ERK1/2 activation: local effect within the rat hypothalamic paraventricular nucleus. Eur J Neurosci 2008; 27:1947-56. [PMID: 18412615 DOI: 10.1111/j.1460-9568.2008.06184.x] [Citation(s) in RCA: 195] [Impact Index Per Article: 12.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
Abstract
The neuropeptide oxytocin (OT) modulates social behaviours and is an important anxiolytic substance of the brain. However, sites of action and the intracellular signalling pathways downstream of OT receptors (OTR) within the brain remain largely unknown. In the present studies, we localized the anxiolytic effect of OT by bilateral microinfusion of OT (0.01 nmol/0.5 microL) into the hypothalamic paraventricular nucleus (PVN) in male rats using both the elevated plus-maze and the light-dark box. Moreover, intracerebroventricular administration of OT, but not of the related neuropeptide vasopressin (VP), dose-dependently activated the extracellular signal-regulated kinase 1/2 (ERK1/2) cascade. Specifically, OT induced the phosphorylation of Raf-1, MEK1/2 and ERK1/2 in the hypothalamus in vivo and in hypothalamic H32 neurons via EGF receptors. OT-induced ERK1/2 phosphorylation was immunohistochemically localized within VP neurons of the PVN and the supraoptic nucleus. Importantly, the anxiolytic effect of OT within the PVN was prevented by local inhibition of the MAP kinase cascade with a MEK1/2 inhibitor (U0126, 0.5 nmol/0.5 microL) locally infused prior to OT, indicating the causal involvement of this intracellular signalling cascade in the behavioural effect of OT. OT effects within the hypothalamus may have far-reaching implications for the regulation of emotionality and social behaviours and, consequently, for the development of possible therapeutic strategies to treat affective disorders. Thus, OTR agonism or activation of the ERK1/2 cascade, specifically within the hypothalamus, may provide therapeutically relevant mechanisms.
Collapse
Affiliation(s)
- Annegret Blume
- Department of Behavioural and Molecular Neuroendocrinology, Institute of Zoology, University of Regensburg, Germany
| | | | | | | | | | | | | |
Collapse
|
37
|
Abstract
Activin is a pleiotropic growth factor with a broad pattern of tissue distribution that includes reproductive tissues. Although direct actions of activin have been described in gonadal and uterine tissues, actions in the myometrium have not been defined. In this study we have characterized the responsiveness of uterine tissue and myometrial cell lines to activin-A. Uterine tissue and two myometrial cell lines, PHM1 (pregnant human myometrial 1) and hTERT HM (telomerase reverse transcriptase-infected human myometrial) respond to activin-A as measured by phosphorylation of Smad-2. Those cell lines express a full complement of activin receptors, as well as activin beta(A) subunit and follistatin. Activin inhibited proliferation of PHM1 and human telomerase reverse transcriptase-infected human myometrial cell line cells, with more extensive growth inhibition observed in PHM1s. In PHM1s, activin-A decreased oxytocin receptor and HoxA-10 mRNA expression but did not alter total progesterone receptor, cyclooxygenase-2 (Cox-2), and connexin 43 mRNA expression levels. Furthermore, treatment of PHM1 myometrial cells with activin-A attenuated oxytocin and thromboxaneA2 induced intracellular Ca(2+) accumulation. In conclusion, myometrial cells are activin sensitive, and activin-A can regulate myometrial cell functions.
Collapse
Affiliation(s)
- Pasquapina Ciarmela
- The Clayton Foundation Laboratories for Peptide Biology, The Salk Institute, 10010 North Torrey Pines Road, La Jolla, California 92037, USA
| | | | | |
Collapse
|
38
|
Stefanidis K, Loutradis D, Anastasiadou V, Bletsa R, Kiapekou E, Drakakis P, Beretsos P, Elenis E, Mesogitis S, Antsaklis A. Oxytocin receptor- and Oct-4-expressing cells in human amniotic fluid. Gynecol Endocrinol 2008; 24:280-4. [PMID: 18569033 DOI: 10.1080/09513590801977167] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 10/21/2022] Open
Abstract
BACKGROUND/AIMS The present clinical and molecular study aimed at investigating the presence of the genes encoding oxytocin receptor (OT-R) and Oct-4 in human amniotic fluid cells. METHODS Amniotic fluid samples were obtained from amniocentesis. Cells from human amniotic fluid samples were analyzed for mRNA expression of OT-R and Oct-4 via reverse transcription-polymerase chain reaction (RT-PCR). Immunocytochemistry was also performed with OT-R and Oct-4 antibodies. RESULTS RT-PCR from 10 independent amniocentesis samples demonstrated the expression of OT-R and Oct-4 mRNA. The cells also showed strong immunoreactivity for molecular markers of OT-R and Oct-4. CONCLUSION OT-R and Oct-4 are expressed in human amniotic fluid cells. The role of oxytocin in the physiology and pathophysiology of amniotic fluid cells remains to be settled.
Collapse
Affiliation(s)
- Konstantinos Stefanidis
- Laboratory of Stem Cells, Division of Reproductive Medicine, Alexandra Maternity Hospital, Athens, Greece.
| | | | | | | | | | | | | | | | | | | |
Collapse
|
39
|
Zhong M, Murtazina DA, Phillips J, Ku CY, Sanborn BM. Multiple signals regulate phospholipase CBeta3 in human myometrial cells. Biol Reprod 2008; 78:1007-17. [PMID: 18322273 DOI: 10.1095/biolreprod.107.064485] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/21/2023] Open
Abstract
Phospholipase CB3 (PLCB3) serine(1105) (S(1105)), a substrate for multiple protein kinases, represents a potential point of convergence of several signaling pathways in the myometrium. To explore this hypothesis, the regulation of PLCB3-S(1105) phosphorylation (P-S(1105)) was studied in immortalized and primary human myometrial cells. 8-[4-chlorophenylthio] (CPT)-cAMP and calcitonin gene-related peptide (CALCA) transiently increased P-S(1105). Relaxin also stimulated P-S(1105); this effect was partially blocked by the protein kinase A (PRKA) inhibitor, Rp-8-CPT-cAMPS. Oxytocin, which stimulates Galphaq-mediated pathways, also rapidly increased P-S(1105), as did prostaglandin F2alpha and ATP. Oxytocin-stimulated phosphorylation was blocked by protein kinase C (PRKC) inhibitor Go6976 and by pretreatment overnight with a phorbol ester. Cypermethrin, a PP2B phosphatase inhibitor, but not okadaic acid, a PP1/PP2A inhibitor, prolonged the effect of CALCA on P-S(1105), whereas the reverse was the case for the oxytocin-stimulated increase in P-S(1105). PLCB3 was the predominant PLC isoform expressed in the myometrial cells and PLCB3 short hairpin RNA constructs significantly attenuated oxytocin-stimulated increases in intracellular calcium. oxytocin-induced phosphatidylinositol (PI) turnover was inhibited by CPT-cAMP and okadaic acid, but was enhanced by pretreatment with Go6976. CPT-cAMP inhibited oxytocin-stimulated PI turnover in the presence of overexpressed PLCB3, but not overexpressed PLCB3-S(1105)A. These data demonstrate that both negative crosstalk from the cAMP/PRKA pathway and a negative feedback loop in the oxytocin/G protein/PLCB pathway involving PRKC operate in myometrial cells and suggest that different protein phosphatases predominate in mediating P-S(1105) dephosphorylation in these pathways. The integration of multiple signal components at the level of PLCB3 may be important to its function in the myometrium.
Collapse
Affiliation(s)
- Miao Zhong
- Department of Biomedical Sciences, Colorado State University, Fort Collins, Colorado 80523, USA
| | | | | | | | | |
Collapse
|
40
|
Lee SH, Heo JS, Lee MY, Han HJ. Effect of dihydrotestosterone on hydrogen peroxide-induced apoptosis of mouse embryonic stem cells. J Cell Physiol 2008; 216:269-75. [DOI: 10.1002/jcp.21402] [Citation(s) in RCA: 32] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
|
41
|
Devost D, Carrier ME, Zingg HH. Oxytocin-induced activation of eukaryotic elongation factor 2 in myometrial cells is mediated by protein kinase C. Endocrinology 2008; 149:131-8. [PMID: 17947356 DOI: 10.1210/en.2007-0548] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/05/2023]
Abstract
The nonapeptide oxytocin (OT) mediates a wide spectrum of biological action, many of them related to reproduction. Recently, we have shown that OT exerts a trophic effect on uterine smooth muscle cells and induces dephosphorylation, and thus activation, of the translation elongation factor eukaryotic elongation factor 2 (eEF2). The present study was designed to elucidate the mechanisms underlying this novel action of OT in the well-characterized human myometrial cell line hTERT-C3. Pathways known to induce eEF2 dephosphorylation are mammalian target of rapamycin (mTOR), and the MAPKs ERK1/2 and p38. Using a panel of chemical inhibitors of specific signaling pathways, we determined that none of these pathways played a role in OT-mediated eEF2 dephosphorylation. Because the OT receptor is a G protein-coupled receptor linked to Galphaq, we tested the possibility that this OT action was mediated via protein kinase C (PKC). PKC activity was blocked by application of the general PKC chemical inhibitor Go6983 or by incubation with the cell-permeable PKC inhibitor peptide myr-psi PKC. With either approach, the effect of OT on eEF2 dephosphorylation was suppressed, indicating that the PKC pathway is essential for this OT action. Consistent with this idea, we also found that direct stimulation of PKC with the phorbol ester phorbol 12-myristate 13-acetate induced eEF2 dephosphorylation. Moreover, we observed that the stimulatory effect of OT on [(35)S]methionine incorporation into nascent proteins was blocked by PKC inhibition. Overall, these results define a novel hormonal signaling pathway that leads to eEF2 dephosphorylation and activation of protein synthesis.
Collapse
Affiliation(s)
- Dominic Devost
- Department of Pharmacology & Therapeutics, McGill University, 3655 Promenade Sir-William-Osler, Montreal, Quebec, Canada H3G 1Y6
| | | | | |
Collapse
|
42
|
Wang YF, Hatton GI. Interaction of extracellular signal-regulated protein kinase 1/2 with actin cytoskeleton in supraoptic oxytocin neurons and astrocytes: role in burst firing. J Neurosci 2007; 27:13822-34. [PMID: 18077694 PMCID: PMC6673636 DOI: 10.1523/jneurosci.4119-07.2007] [Citation(s) in RCA: 40] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/05/2006] [Revised: 10/14/2007] [Accepted: 10/25/2007] [Indexed: 11/21/2022] Open
Abstract
Neuronal firing patterns determine the manner of neurosecretion, the underlying mechanisms of which are poorly understood. Using supraoptic nuclei in brain slices from lactating rats, we examined the involvement of extracellular signal-regulated protein kinase 1/2 (ERK1/2) and filamentous actin (F-actin) in burst generation by oxytocin (OT) neurons. Blocking phosphorylation of ERK1/2 (pERK1/2) decreased miniature EPSCs and blocked OT-evoked bursts, as did intracellularly loading an antibody against pERK1/2. OT (10 pM) increased cytosolic pERK1/2 close to the cell membrane within the first 5 min, subsiding by 30 min, whereas OT elicited pERK1/2 nuclear translocation in closely associated supraoptic astrocytes. The increased pERK1/2 was tightly correlated with spatiotemporal actin dynamics. In OT neurons, OT initially increased F-actin, particularly at membrane subcortical areas, and then decreased it after 30 min. Both polymerization and depolymerization of actin cytoskeleton were associated with bursts, but only polymerization facilitated OT-evoked bursts. Blocking ERK1/2 activation blocked OT-evoked actin polymerization, whereas depolymerizing F-actin increased pERK1/2 expression. These changes were further identified in vivo. In intact animals, suckling increased ERK1/2 activation in the cytosol and membrane subcortical area F-actin formation in OT neurons, whereas it increased F-actin concentration in astrocytic somata. Coimmunoprecipitation showed that suckling increased molecular interactions between pERK1/2 and actin. Finally, two different blockers of ERK1/2 kinase injected intracerebroventricularly reduced suckling-evoked milk ejections. This is the first demonstration that OT mediation of suckling-evoked bursts/milk ejections is via interactions between pERK1/2 and actin cytoskeleton.
Collapse
Affiliation(s)
- Yu-Feng Wang
- Department of Cell Biology and Neuroscience, University of California, Riverside, California 92521, USA.
| | | |
Collapse
|
43
|
Abstract
G proteins provide signal-coupling mechanisms to heptahelical cell surface receptors and are critically involved in the regulation of different mitogen-activated protein kinase (MAPK) networks. The four classes of G proteins, defined by the G(s), G(i), G(q) and G(12) families, regulate ERK1/2, JNK, p38MAPK, ERK5 and ERK6 modules by different mechanisms. The alpha- as well as betagamma-subunits are involved in the regulation of these MAPK modules in a context-specific manner. While the alpha- and betagamma-subunits primarily regulate the MAPK pathways via their respective effector-mediated signaling pathways, recent studies have unraveled several novel signaling intermediates including receptor tyrosine kinases and small GTPases through which these G-protein subunits positively as well as negatively regulate specific MAPK modules. Multiple mechanisms together with specific scaffold proteins that can link G-protein-coupled receptors or G proteins to distinct MAPK modules contribute to the context-specific and spatio-temporal regulation of mitogen-activated protein signaling networks by G proteins.
Collapse
Affiliation(s)
- Z G Goldsmith
- Fels Institute for Cancer Research and Molecular Biology, Temple University School of Medicine, Philadelphia, PA 19140, USA
| | | |
Collapse
|
44
|
Sanborn BM. Hormonal signaling and signal pathway crosstalk in the control of myometrial calcium dynamics. Semin Cell Dev Biol 2007; 18:305-14. [PMID: 17627855 PMCID: PMC2000447 DOI: 10.1016/j.semcdb.2007.05.007] [Citation(s) in RCA: 31] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/03/2007] [Accepted: 05/03/2007] [Indexed: 10/23/2022]
Abstract
Understanding the basis for the control of myometrial contractant and relaxant signaling pathways is important to understanding how to manage myometrial contractions. Signaling pathways are influenced by the level of expression of the signals and signal pathway components, the location of these components in the appropriate subcellular environment, and covalent modification. Crosstalk between these pathways regulates the effectiveness of signal transduction and represents an important way by which hormones can regulate phenotype. This review deals primarily with signaling pathways that control Ca2+ entry and intracellular release, as well as the interplay between these pathways.
Collapse
Affiliation(s)
- Barbara M Sanborn
- Department of Biomedical Sciences, Colorado State University, Fort Collins, CO 80523-1680, USA.
| |
Collapse
|
45
|
Zhong M, Parish B, Murtazina DA, Ku CY, Sanborn BM. Amino acids in the COOH-terminal region of the oxytocin receptor third intracellular domain are important for receptor function. Am J Physiol Endocrinol Metab 2007; 292:E977-84. [PMID: 17148753 DOI: 10.1152/ajpendo.00531.2005] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/04/2023]
Abstract
Previously, residue K6.30 in the COOH-terminal region of the third intracellular domain (3iC) of the oxytocin (OT) receptor (OTR) was identified as important for receptor function leading to phospholipase C activation in both OTR and the vasopressin V(2) receptor (V(2)R) chimera V(2)ROTR3iC. Substitution of either A6.28K or V6.30K in wild-type V(2)R did not recapitulate the increase in phosphatidylinositide (PI) turnover observed in V(2)ROTR3iC. Hence, the role of K6.30 may be context-specific. Deletion of two NH(2)-terminal OTR3iC segments in the V(2)ROTR3iC chimera did not diminish vasopressin-stimulated PI turnover, whereas deletion of RVSSVKL (residues 6.19-6.25) reduced receptor expression. Deletion of this sequence in wild-type OTR reduced expression by 50% without affecting affinity for [(3)H]OT. This OTR mutant was unable to activate PI turnover or extracellular signal-regulated kinase 1/2 phosphorylation. The effects of alanine substitution for individual residues in RVSSVKL indicated differential importance for OTR function. The R6.19A substitution lost high-affinity sites for [(3)H]OT and the ability to stimulate PI turnover. Affinity for [(3)H]OT and membrane expression was not affected by any other substitutions. OTR-V6.20A and OTR-K6.24A mutants functioned as well as wild-type OTR, whereas OTR S6.21A, S6.22A, and V6.23A mutants exhibited impaired abilities to activate PI turnover (20-40% of OTR), and the OTR-L6.25A mutant exhibited constitutive activity. In conclusion, specific amino acids in the RVSSVKL segment in the COOH-terminal region of the third intracellular domain of OTR influence the ability of OTR to activate G protein-mediated actions.
Collapse
Affiliation(s)
- Miao Zhong
- Department of Biomedical Sciences, Colorado State University, Fort Collins, CO 80523, USA
| | | | | | | | | |
Collapse
|
46
|
Abstract
Pulsatile neuropeptide secretion is associated with burst firing patterns; however, intracellular signaling cascades leading to bursts remain unclear. We explored mechanisms underlying burst firing in oxytocin (OT) neurons in the supraoptic nucleus in brain slices from lactating rats. Application of 10 pm OT for 30 min or progressively rising OT concentrations from 1 to 100 pm induced burst firing in OT neurons in patch-clamp recordings. Burst generation was blocked by OT antagonist and ionotropic glutamate receptor blockers or tetanus toxin. Blocking G-protein activation with suramin or intracellular GDP-beta-S, but not intracellularly administered antibody against the OT-receptor (OTR) C terminus, blocked bursts. Moreover, pretreatment of slices with pertussis toxin, an inhibitor of G(i/o)-proteins, did not block OT-evoked bursts, suggesting that G(i)/G(o) activation is unnecessary for burst generation. Thus, we further examined G alpha(q/11)-associated signaling pathways in OT-evoked bursts. Inhibition of phospholipase C or RhoA/Rho kinase did not block bursts. Activation of G betagamma subunits using myristoylated G betagamma-binding peptide (mSIRK) caused bursts, whereas intracellularly loaded antibody against G beta subunit blocked OT-evoked bursts. Blocking Src family kinase, but not phosphatidylinositol 3-kinase, occluded OT-evoked bursts. Similar to the effects of OT on EPSCs, mSIRK inhibited tonic EPSCs and elicited EPSC clustering. Finally, suckling caused dissociation of OTRs and G beta subunits from G alpha(q/11) subunits shown by coimmunoprecipitation and immunocytochemistry, supporting crucial roles for OTRs and G betagamma subunits in the milk-ejection reflex. We conclude that G betagamma subunits play a dominant role in burst firing evoked by applied OT or by suckling.
Collapse
Affiliation(s)
- Yu-Feng Wang
- Department of Cell Biology and Neuroscience, University of California, Riverside, Riverside, California 92521, USA.
| | | |
Collapse
|
47
|
Zhou XB, Lutz S, Steffens F, Korth M, Wieland T. Oxytocin Receptors Differentially Signal via Gq and Gi Proteins in Pregnant and Nonpregnant Rat Uterine Myocytes: Implications for Myometrial Contractility. Mol Endocrinol 2007; 21:740-52. [PMID: 17170070 DOI: 10.1210/me.2006-0220] [Citation(s) in RCA: 39] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/19/2022] Open
Abstract
AbstractOxytocin (OT) receptors are important regulators of myometrial contractility. By using the activity of large conductance Ca2+-activated K+ (BKCa) channels as readout, we analyzed OT signaling in cells from nonpregnant (NPM) and pregnant (PM) rat myometrium in detail. In nystatin-perforated whole-cell patches from NPM cells, which leave the intracellular integrity intact, OT transiently increased BKCa-mediated outward currents (Iout). This OT-evoked Iout was caused by the Ca2+ transients in response to the Gq/11-mediated activation of phospholipase C and was inhibited by activation of protein kinase A (PKA). In an open-access whole-cell patch (OAP), the OT-induced transient rise in Iout was disrupted whereas the regulation of BKCa by the cAMP/PKA cascade remained intact. OT counteracted the isoprenaline, i.e. the β-adrenoceptor/Gs-mediated effect in NPM cells measured in OAP. In contrast, OT further enhanced the β-adrenoceptor/Gs-mediated effect on BKCa activity in PM cells. All OT effects in the OAP were mediated by pertussis toxin-sensitive Gi proteins and PKA. By quantitative real-time PCR and overexpression of the recombinant protein, we demonstrate that an up-regulation of the Gβγ-stimulated adenylyl cyclase II during pregnancy is most likely responsible for this switch. By studying the OT-evoked Iout in nystatin-perforated whole-cell patches of PM cells, we further detected that the OT receptor/Giβγ-mediated coactivation of adenylyl cyclase II enhanced the β-adrenoceptor/Gs-induced suppression of the OT-evoked Ca2+ transients and thus diminishes and self-limits OT-induced contractility. The differential regulation of the PKA-mediated suppression of OT-evoked Ca2+ transients and BKCa activity likely supports uterine quiescence during pregnancy.
Collapse
Affiliation(s)
- Xiao-Bo Zhou
- Institut für Pharmakologie für Pharmazeuten, Universitätsklinikum Hamburg-Eppendorf, Martinistrasse 52, D-20246 Hamburg, Germany
| | | | | | | | | |
Collapse
|
48
|
Abstract
One of the classical biological actions mediated by the posterior pituitary hormone oxytocin (OT) is contraction of the uterus at parturition. Moreover, premature activation of the OT system is thought to contribute to preterm labor, a major clinical problem in obstetrical practice. However, the molecular mechanisms linking activation of the OT receptor (OTR) to myometrial contractions are not fully understood. Here, we describe an in vitro system that should serve as a useful tool to study this question at a cellular level. The system consists of a collagen lattice contraction assay and two different human myometrial cell lines: a cell clone from a telomerase-immortalized human myometrial cell population (hTERT-C3) as well as a cell line derived from a primary culture of human myometrial cells (M11). Using this approach, we observed that 1 nM OT promoted an almost maximal effect on cell contraction in both cell lines tested. Furthermore, this dose-dependent, OT-induced contraction was antagonized by the specific OTR antagonist d(CH(2))(5)[Tyr(Me)(2),Thr(4),Tyr-NH(2)(9)]OVT as well as the clinically used antagonist atosiban. This cell line-based contraction assay enables the application of molecular tools aimed at suppressing or overexpressing specific genes. It is also amenable to high-throughput testing approaches. Therefore, this system represents a powerful and improved experimental model that should facilitate the study of the molecular signal transduction pathways involved in the uterotonic actions of OT.
Collapse
Affiliation(s)
- Dominic Devost
- Dept. of Pharmacology and Therapeutics, McGill University, 3655 Promenade Sir-William-Osler, Montreal, QC, H3G 1Y6, Canada
| | | |
Collapse
|
49
|
Nicholson HD, Whittington K. Oxytocin and the human prostate in health and disease. INTERNATIONAL REVIEW OF CYTOLOGY 2007; 263:253-86. [PMID: 17725969 DOI: 10.1016/s0074-7696(07)63006-x] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/17/2022]
Abstract
Oxytocin is a peptide hormone produced by the neurohypophysis. The discovery that the peptide is produced locally within the male and female reproductive tracts has raised the possibility that oxytocin may have paracrine and autocrine actions outside of the nervous system. Oxytocin and its receptor have been identified in the human prostate. The prostate is an androgen-dependent organ whose function is to secrete components of the seminal fluid. Oxytocin has been shown to modulate contractility of prostate tissue and also to regulate local concentrations of the biologically active androgens. Oxytocin has also been shown to regulate cell growth. Prostate disease is common and results from abnormal growth of the gland. Oxytocin concentrations are altered in both benign and malignant prostate diseases and in vitro studies suggest that the peptide may be involved in the pathophysiology of these diseases.
Collapse
Affiliation(s)
- Helen D Nicholson
- Department of Anatomy and Structural Biology, University of Otago, New Zealand
| | | |
Collapse
|
50
|
Weiner CP, Mason C, Hall G, Ahmad U, Swaan P, Buhimschi IA. Pregnancy and estradiol modulate myometrial G-protein pathways in the guinea pig. Am J Obstet Gynecol 2006; 195:275-87. [PMID: 16681987 DOI: 10.1016/j.ajog.2005.12.050] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/03/2005] [Revised: 12/09/2005] [Accepted: 12/22/2005] [Indexed: 10/24/2022]
Abstract
OBJECTIVE Coupled to hundreds of receptors, G-proteins modulate signal transduction pathways and are important hormonal targets. The first objective was to determine the effect of pregnancy and estradiol on myometrial guanosine triphosphatase activity. The second objective was to begin dissecting the molecular mechanism(s) underlying alterations in guanosine triphosphatase activity. STUDY DESIGN Myometrial tissue was obtained from pregnant, nonpregnant, and ovariectomized untreated and estradiol-treated guinea pigs. Myometrial membranes were prepared by homogenization and differential centrifugation. Basal high-affinity specific guanosine triphosphatase activity was quantitated by enzymatic assay and expressed in rhomol 32Pi per milligram protein per minute. Guanosine triphosphatase activity was stimulated using oxytocin, isoproterenol, and prostaglandin F2alpha. Specific G-protein subunits were quantitated using Western blots. G-protein associated gene expression was semiquantitated using HGU133A gene array chips from Affymetrix. RESULTS Basal myometrial guanosine triphosphatase activity was increased in pregnant compared with nonpregnant animals. Estradiol increased basal myometrial guanosine triphosphatase activity, compared with untreated controls. The effect of estradiol on stimulated activity was agonist dependent. Both Galphas and Galphai isoform 1 protein levels were increased in myometrium from late pregnant compared with nonpregnant animals. By late gestation, the messenger ribonucleic acid levels of those genes were unaltered, compared with the nonpregnant animal. In general, the impact of pregnancy on G-protein family member gene messenger ribonucleic acid expression was modest. Only the small guanosine triphosphatase Rap1b demonstrated altered expression more than 2-fold during either myometrial quiescence (midpregnancy) or activation (term pregnancy) (up 3-fold during quiescence). Genomic network analyses revealed that the expression of another small guanosine triphosphatase, Rab7, was exclusively up-regulated (80%) during quiescence. During late pregnancy, network analysis showed that only G-protein beta was exclusively altered (up-regulated). Estradiol mimicked the pregnancy effect on both transcription and translation of G-protein family members for some but not all potentially relevant genes. CONCLUSION The increase in functional myometrial guanosine triphosphatase activity during pregnancy may reflect increased synthesis of 1 or more small guanosine triphosphatase.
Collapse
Affiliation(s)
- Carl P Weiner
- Department of Obstetrics and Gynecology, University of Kansas School of Medicine, Kansas City, KS 66160-7316, USA.
| | | | | | | | | | | |
Collapse
|