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Ahlström FH, Viisanen H, Karhinen L, Velagapudi V, Blomqvist KJ, Lilius TO, Rauhala PV, Kalso EA. Gene expression in the dorsal root ganglion and the cerebrospinal fluid metabolome in polyneuropathy and opioid tolerance in rats. IBRO Neurosci Rep 2024; 17:38-51. [PMID: 38933596 PMCID: PMC11201153 DOI: 10.1016/j.ibneur.2024.05.006] [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: 10/05/2023] [Revised: 05/13/2024] [Accepted: 05/20/2024] [Indexed: 06/28/2024] Open
Abstract
First-line pharmacotherapy for peripheral neuropathic pain (NP) of diverse pathophysiology consists of antidepressants and gabapentinoids, but only a minority achieve sufficient analgesia with these drugs. Opioids are considered third-line analgesics in NP due to potential severe and unpredictable adverse effects in long-term use. Also, opioid tolerance and NP may have shared mechanisms, raising further concerns about opioid use in NP. We set out to further elucidate possible shared and separate mechanisms after chronic morphine treatment and oxaliplatin-induced and diabetic polyneuropathies, and to identify potential diagnostic markers and therapeutic targets. We analysed thermal nociceptive behaviour, the transcriptome of dorsal root ganglia (DRG) and the metabolome of cerebrospinal fluid (CSF) in these three conditions, in rats. Several genes were differentially expressed, most following oxaliplatin and least after chronic morphine treatment, compared with saline-treated rats. A few genes were differentially expressed in the DRGs in all three models (e.g. Csf3r and Fkbp5). Some, e.g. Alox15 and Slc12a5, were differentially expressed in both diabetic and oxaliplatin models. Other differentially expressed genes were associated with nociception, inflammation, and glial cells. The CSF metabolome was most significantly affected in the diabetic rats. Interestingly, we saw changes in nicotinamide metabolism, which has been associated with opioid addiction and withdrawal, in the CSF of morphine-tolerant rats. Our results offer new hypotheses for the pathophysiology and treatment of NP and opioid tolerance. In particular, the role of nicotinamide metabolism in opioid addiction deserves further study.
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Affiliation(s)
- Fredrik H.G. Ahlström
- Department of Pharmacology, Faculty of Medicine, Biomedicum 1, University of Helsinki, Haartmaninkatu 8, 00014, Finland
- Individualized Drug Therapy Research Programme, Faculty of Medicine, Biomedicum 1, University of Helsinki, Haartmaninkatu 8, 00014, Finland
| | - Hanna Viisanen
- Department of Pharmacology, Faculty of Medicine, Biomedicum 1, University of Helsinki, Haartmaninkatu 8, 00014, Finland
- Individualized Drug Therapy Research Programme, Faculty of Medicine, Biomedicum 1, University of Helsinki, Haartmaninkatu 8, 00014, Finland
| | - Leena Karhinen
- Department of Pharmacology, Faculty of Medicine, Biomedicum 1, University of Helsinki, Haartmaninkatu 8, 00014, Finland
| | - Vidya Velagapudi
- Metabolomics Unit, Institute for Molecular Medicine Finland FIMM, University of Helsinki, P.O. Box 20, FI-00014, Finland
| | - Kim J. Blomqvist
- Department of Pharmacology, Faculty of Medicine, Biomedicum 1, University of Helsinki, Haartmaninkatu 8, 00014, Finland
- Individualized Drug Therapy Research Programme, Faculty of Medicine, Biomedicum 1, University of Helsinki, Haartmaninkatu 8, 00014, Finland
| | - Tuomas O. Lilius
- Department of Pharmacology, Faculty of Medicine, Biomedicum 1, University of Helsinki, Haartmaninkatu 8, 00014, Finland
- Individualized Drug Therapy Research Programme, Faculty of Medicine, Biomedicum 1, University of Helsinki, Haartmaninkatu 8, 00014, Finland
- Department of Clinical Pharmacology, University of Helsinki and Helsinki University Hospital, Tukholmankatu 8C, 00014, Finland
- Department of Emergency Medicine and Services, University of Helsinki and HUS Helsinki University Hospital, Haartmaninkatu 4, Helsinki 00290, Finland
| | - Pekka V. Rauhala
- Department of Pharmacology, Faculty of Medicine, Biomedicum 1, University of Helsinki, Haartmaninkatu 8, 00014, Finland
- Individualized Drug Therapy Research Programme, Faculty of Medicine, Biomedicum 1, University of Helsinki, Haartmaninkatu 8, 00014, Finland
| | - Eija A. Kalso
- Department of Pharmacology, Faculty of Medicine, Biomedicum 1, University of Helsinki, Haartmaninkatu 8, 00014, Finland
- SleepWell Research Programme, Faculty of Medicine, , University of Helsinki, Haartmaninkatu 3, 00014, Finland
- Department of Anaesthesiology and Intensive Care Medicine, Helsinki University Hospital and University of Helsinki, HUS, Stenbäckinkatu 9, P.O. Box 440, 00029, Finland
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Talaat IM, Yakout NM, Soliman AS, Venkatachalam T, Vinod A, Eldohaji L, Nair V, Hareedy A, Kandil A, Abdel-Rahman WM, Hamoudi R, Saber-Ayad M. Evaluation of Galanin Expression in Colorectal Cancer: An Immunohistochemical and Transcriptomic Study. Front Oncol 2022; 12:877147. [PMID: 35707368 PMCID: PMC9190230 DOI: 10.3389/fonc.2022.877147] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/14/2022] [Accepted: 04/27/2022] [Indexed: 01/02/2023] Open
Abstract
Colorectal cancer (CRC) represents around 10% of all cancers, with an increasing incidence in the younger age group. The gut is considered a unique organ with its distinctive neuronal supply. The neuropeptide, human galanin, is widely distributed in the colon and expressed in many cancers, including the CRC. The current study aimed to explore the role of galanin at different stages of CRC. Eighty-one CRC cases (TNM stages I – IV) were recruited, and formalin-fixed paraffin-embedded samples were analyzed for the expression of galanin and galanin receptor 1 (GALR1) by immunohistochemistry (IHC). Galanin intensity was significantly lower in stage IV (n= 6) in comparison to other stages (p= 0.037 using the Mann-Whitney U test). Whole transcriptomics analysis using NGS was performed for selected samples based on the galanin expression by IHC [early (n=5) with high galanin expression and late (n=6) with low galanin expression]. Five differentially regulated pathways (using Absolute GSEA) were identified as drivers for tumor progression and associated with higher galanin expression, namely, cell cycle, cell division, autophagy, transcriptional regulation of TP53, and immune system process. The top shared genes among the upregulated pathways are AURKA, BIRC5, CCNA1, CCNA2, CDC25C, CDK2, CDK6, EREG, LIG3, PIN1, TGFB1, TPX2. The results were validated using real-time PCR carried out on four cell lines [two primaries (HCT116 and HT29) and two metastatic (LoVo and SK-Co-1)]. The current study shows galanin as a potential negative biomarker. Galanin downregulation is correlated with advanced CRC staging and linked to cell cycle and division, autophagy, transcriptional regulation of TP53 and immune system response.
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Affiliation(s)
- Iman M. Talaat
- Department of Clinical Sciences, College of Medicine, University of Sharjah, Sharjah, United Arab Emirates
- Sharjah Institute for Medical Research, University of Sharjah, Sharjah, United Arab Emirates
- Pathology Department, Faculty of Medicine, Alexandria University, Alexandria, Egypt
| | - Nada M. Yakout
- Pathology Department, Faculty of Medicine, Alexandria University, Alexandria, Egypt
| | | | - Thenmozhi Venkatachalam
- Sharjah Institute for Medical Research, University of Sharjah, Sharjah, United Arab Emirates
- Department of Physiology and Immunology, College of Medicine and Health Science, Khalifa University, Abu Dhabi, United Arab Emirates
| | - Arya Vinod
- Sharjah Institute for Medical Research, University of Sharjah, Sharjah, United Arab Emirates
| | - Leen Eldohaji
- Sharjah Institute for Medical Research, University of Sharjah, Sharjah, United Arab Emirates
| | - Vidhya Nair
- Sharjah Institute for Medical Research, University of Sharjah, Sharjah, United Arab Emirates
| | - Amal Hareedy
- Pathology Department, Faculty of Medicine, Cairo University, Cairo, Egypt
| | - Alaa Kandil
- Clinical Oncology and Nuclear Medicine Department, Faculty of Medicine, Alexandria University, Cairo, Egypt
| | - Wael M. Abdel-Rahman
- Sharjah Institute for Medical Research, University of Sharjah, Sharjah, United Arab Emirates
- Department of Medical Laboratory Sciences, College of Health Sciences, University of Sharjah, Sharjah, United Arab Emirates
| | - Rifat Hamoudi
- Department of Clinical Sciences, College of Medicine, University of Sharjah, Sharjah, United Arab Emirates
- Sharjah Institute for Medical Research, University of Sharjah, Sharjah, United Arab Emirates
- Division of Surgery and Interventional Science, University College London, London, United Kingdom
| | - Maha Saber-Ayad
- Department of Clinical Sciences, College of Medicine, University of Sharjah, Sharjah, United Arab Emirates
- Sharjah Institute for Medical Research, University of Sharjah, Sharjah, United Arab Emirates
- Pharmacology Department, Faculty of Medicine, Cairo University, Cairo, Egypt
- *Correspondence: Maha Saber-Ayad,
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Galanin enhanced insulin-mediated intracellular signaling by regulating the stability of membrane-localized insulin/IR. Cell Biochem Biophys 2022; 80:321-330. [PMID: 34997549 DOI: 10.1007/s12013-021-01049-x] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 11/18/2021] [Indexed: 11/03/2022]
Abstract
Previous studies have shown that insulin has the important regulatory effect on the intestinal tract. However, until now, the biological properties of insulin on intestinal cell has not been revealed. Therefore, in the current research, we first studied the cell characteristics and signaling profiles of insulin in the intestinal cell model, and found that insulin can be internalized into the cytoplasm in a time-dependent manner. After internalization, insulin transported into different type of endosomes. More importantly, we explored the effect of galanin on insulin-mediated signaling pathways (galanin is a polypeptide composed of 29 amino acid residues, galanin is widely distributed in the central and peripheral nervous system and has a variety of biological activities), and found that galanin can increase insulin sensitivity by regulating insulin receptor (IR)-mediated signal transduction pathways. We further study the potential molecular mechanism by which galanin enhances insulin sensitivity, and found that galanin could increase the time of insulin acting on the cell membrane. Further experiments showed that galanin could stabilize the membrane-localized insulin/IR, which may be an important new potential mechanism by which galanin improves the biological activity of insulin. This study laid the foundation for exploring the relationship between galanin and insulin sensitivity.
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Li H, Wang T, Shi C, Yang Y, Li X, Wu Y, Xu ZQD. Inhibition of GALR1 in PFC Alleviates Depressive-Like Behaviors in Postpartum Depression Rat Model by Upregulating CREB-BNDF and 5-HT Levels. Front Psychiatry 2018; 9:588. [PMID: 30487761 PMCID: PMC6246688 DOI: 10.3389/fpsyt.2018.00588] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/16/2018] [Accepted: 10/25/2018] [Indexed: 01/12/2023] Open
Abstract
Estrogen (E2) withdrawal is a core pathology mechanism for postpartum depression (PPD). Galanin (GAL), an estrogen-inducible neuropeptide has also been reported to be associated with depression. However, it still remains unclear which GAL receptors (GALRs) are involved in PPD pathologic process. In the present study, we discovered that the expression of GALR1, rather than GALR2/3, was upregulated with a region-specific pattern in the prefrontal cortex (PFC) of E2 withdrawal induced PPD model rats. Meanwhile, c-fos was also upregulated only in PFC in the same animal model. Injection of GALR1-siRNA into the bilateral PFC ameliorated depressive-like behavior of PPD rats, suggesting that the upregulation of GALR1 in PFC is involved in PPD. Moreover, Western Blot and HPLC assays demonstrated that the downregulation of CREB-BDNF signaling and 5-HT levels in the PFC of PPD rats were reversed after GALR1-siRNA injection. These comprehensive results suggest that the knock down of GALR1 in PFC alleviates depressive-like behaviors and reverse downregulation of CREB-BDNF and 5-HT levels in PPD rat model. HIGHLIGHTS Expression level of GALR1 mRNA was significantly increased in PFC of estrogen withdraw-induced PPD rats. Injecting GALR1-siRNA into PFC alleviated depressive-like behavior and reversed the decrease of 5-HT level and CREB/BDNF signaling in PFC of PPD rats.
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Affiliation(s)
- Hui Li
- Department of Anatomy, Capital Medical University, Beijing, China
| | - Tong Wang
- Beijing Key Laboratory of Neural Regeneration and Repair, Beijing Laboratory of Brain Disorders (Ministry of Science and Technology), Department of Neurobiology, Beijing Institute of Brain Disorders, Capital Medical University, Beijing, China
| | - Cuige Shi
- Department of Cell Biology, National Research Institute of Family Planning, Beijing, China
| | - Yutao Yang
- Beijing Key Laboratory of Neural Regeneration and Repair, Beijing Laboratory of Brain Disorders (Ministry of Science and Technology), Department of Neurobiology, Beijing Institute of Brain Disorders, Capital Medical University, Beijing, China
| | - Xiaoxiao Li
- Beijing Key Laboratory of Neural Regeneration and Repair, Beijing Laboratory of Brain Disorders (Ministry of Science and Technology), Department of Neurobiology, Beijing Institute of Brain Disorders, Capital Medical University, Beijing, China
| | - Yan Wu
- Department of Anatomy, Capital Medical University, Beijing, China
| | - Zhi-Qing David Xu
- Beijing Key Laboratory of Neural Regeneration and Repair, Beijing Laboratory of Brain Disorders (Ministry of Science and Technology), Department of Neurobiology, Beijing Institute of Brain Disorders, Capital Medical University, Beijing, China
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Galanin contributes to monoaminergic dysfunction and to dependent neurobehavioral comorbidities of epilepsy. Exp Neurol 2016; 289:64-72. [PMID: 28013000 DOI: 10.1016/j.expneurol.2016.12.008] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/26/2016] [Revised: 11/23/2016] [Accepted: 12/20/2016] [Indexed: 01/01/2023]
Abstract
Status epilepticus (SE) in rats, along with chronic epilepsy, leads to the development of behavioral impairments resembling depressive disorder and/or attention deficit/hyperactivity disorder (ADHD), thus reflecting respective comorbidities in epilepsy patients. Suppressed neurotransmitter tone in the raphe nucleus (RN)-prefrontal cortex (PFC) serotonergic pathway and in the locus coeruleus (LC)-PFC noradrenergic pathway underlies depressive- and impulsive-like behavioral deficits respectively. We examined possible mechanisms leading to the monoamine dysfunction in brainstem efferents, namely modulatory effects of the neuropeptide galanin on serotonin (5-HT) and norepinephrine (NE) signaling. SE was induced in young adult male Wistar rats by LiCl and pilocarpine. Epileptic rats were categorized vis-à-vis behavioral deficits as not impaired, "depressed" and "impulsive". Depressive- and impulsive-like behaviors were examined in the forced swimming test (FST). The strength of serotonergic transmission in RN-PFC and of noradrenergic transmission in LC-PFC was analyzed using in vivo fast scan cyclic voltammetry. Galanin receptor type 1 (GalR1)/type 2 (GalR2) antagonist M40, and a preferential GalR2 antagonist M871 were administered over 3days locally into either RN or LC by means of ALZET osmotic minipumps connected to locally implanted infusion cannulas. Intra-RN injection of M40 improved serotonergic tone and depressive-like behavior in epileptic "depressed" rats. Intra-LC injection of M40 improved noradrenergic tone and impulsive-like behavior in epileptic "impulsive" rats. The effects of M40 were only observed in impaired subjects. The treatment did not modify neurotransmission and behavior in naïve and epileptic not impaired rats; in "depressed" rats the effects were limited to serotonergic transmission and immobility, while in "impulsive" rats - to noradrenergic transmission and struggling behavior. Intra-RN administration of M871 exacerbated depressive-like behavior, but had no effects on any other of the examined parameters in any category of animals. These findings suggest that endogenous galanin, acting through GalR1 may be involved in the pathophysiology of epilepsy-associated depression and ADHD via inhibiting RN-PFC serotonergic and LC-PFC noradrenergic transmissions respectively.
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Kwiatkowski P, Godlewski J, Kieżun J, Kraziński BE, Kmieć Z. Colorectal cancer patients exhibit increased levels of galanin in serum and colon tissues. Oncol Lett 2016; 12:3323-3329. [PMID: 27899999 PMCID: PMC5103946 DOI: 10.3892/ol.2016.5037] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/02/2015] [Accepted: 07/26/2016] [Indexed: 02/06/2023] Open
Abstract
Galanin (GAL) is a 30-amino acid neuropeptide that is expressed in both the central and peripheral nervous system, including the enteric nervous system (ENS). Increased GAL concentrations have been identified in the blood of colorectal cancer (CRC) patients. The aim of the present study was to assess whether sections of the colon wall containing ENS plexuses or CRC tumor are associated with increased GAL concentrations. Blood samples were collected from 68 CRC patients and 39 healthy volunteers. In addition, samples of CRC tumors and colon wall tissue in close proximity to and distant from the neoplastic tissue were obtained from 22 CRC patients. The GAL concentration of sera and tissue homogenates obtained from three sections of the colon wall (mucosa with submucosa, muscularis externa and CRC tumor) was analyzed by ELISA. The localization of GAL was evaluated using immunohistochemistry and morphometry was used to measure the distribution of GAL-immunoreactive (GAL-Ir) myenteric plexuses in the vicinity of cancer invasion and in sections of the colon wall distant from the tumor. The GAL serum concentration of CRC patients was 2.4 times higher than that of the control group. The GAL concentration was highest in the homogenates of neoplastic tissue and mucosa obtained from the control (distant) section of the intestinal wall, followed by that in the mucosa and muscularis externa proximal to the tumor. The lowest GAL concentrations were identified within the muscular layer of the colon wall located distant from the tumor. Strong GAL immunoreactivity was identified in the cancer cells, intestinal epithelium and the submucosal and myenteric plexuses. Morphometric analysis revealed that the GAL-Ir myenteric plexuses in the vicinity of tumor infiltration were significantly smaller in size than those in the intact section of the large intestine. Furthermore, no associations were identified between the clinicopathological characteristics of CRC patients and GAL serum and tissue concentration. The increased GAL serum concentrations observed in CRC patients in comparison to healthy controls may result from GAL secretion by CRC tumors, however, other sources of GAL cannot be excluded. The atrophy of myenteric plexuses within close proximity to the tumor may affect the colon function of CRC patients. In conclusion, investigation into the presence of GAL in the colon wall and serum of CRC patients revealed that serum and tissue GAL levels may present useful potential biomarkers in CRC patients.
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Affiliation(s)
- Przemysław Kwiatkowski
- Department of Human Histology and Embryology, Faculty of Medical Sciences, University of Warmia and Mazury, 10-082 Olsztyn, Poland
| | - Janusz Godlewski
- Department of Human Histology and Embryology, Faculty of Medical Sciences, University of Warmia and Mazury, 10-082 Olsztyn, Poland
| | - Jacek Kieżun
- Department of Human Histology and Embryology, Faculty of Medical Sciences, University of Warmia and Mazury, 10-082 Olsztyn, Poland
| | - Bartłomiej Emil Kraziński
- Department of Human Histology and Embryology, Faculty of Medical Sciences, University of Warmia and Mazury, 10-082 Olsztyn, Poland
| | - Zbigniew Kmieć
- Department of Human Histology and Embryology, Faculty of Medical Sciences, University of Warmia and Mazury, 10-082 Olsztyn, Poland; Department of Histology, Medical University of Gdańsk, 80-210 Gdańsk, Poland
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7
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Zafar MI, Hu C, Liu D, Shafqat RA, Gao F. Insulin detemir causes lesser weight gain in comparison to insulin glargine: role on hypothalamic NPY and galanin. J Diabetes Res 2014; 2014:458104. [PMID: 25197671 PMCID: PMC4147283 DOI: 10.1155/2014/458104] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/18/2014] [Revised: 07/14/2014] [Accepted: 07/28/2014] [Indexed: 12/21/2022] Open
Abstract
OBJECTIVE Compared with other insulin analogues, insulin detemir induces less weight gain. This study investigated whether this effect was achieved by influencing the hypothalamic appetite regulators neuropeptide Y (NPY) and galanin (GAL). METHODS Type 2 diabetic rat models were established with a high-fat diet and intraperitoneal injection of STZ. All rats were divided into NC, DM, DM+DE and DM+GLA groups. Glycemic levels of all study groups were checked at study onset and after 4 weeks of insulin treatment. Food intake and body weight were monitored during treatment. After 4 weeks, the hypothalamus of rats was examined for NPY and GAL mRNA and protein expression. RESULTS After 4 weeks of treatment, compared with the DM+GLA group, the DM+DE group exhibited less food intake (P < 0.05) and less weight gain (P < 0.05), but showed similar glycemic control. The expression of hypothalamic NPY and GAL at both mRNA and protein level were significantly lower (P < 0.05) in the DM+DE group. CONCLUSION Insulin detemir decreased food intake in type 2 diabetic rats, which led to reduced weight gain when compared to insulin glargine treatment. This effect is likely due to downregulation of hypothalamic NPY and GAL.
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MESH Headings
- Animals
- Blood Glucose/drug effects
- Blood Glucose/metabolism
- Diabetes Mellitus, Experimental/blood
- Diabetes Mellitus, Experimental/chemically induced
- Diabetes Mellitus, Experimental/drug therapy
- Diabetes Mellitus, Experimental/genetics
- Diabetes Mellitus, Experimental/physiopathology
- Diabetes Mellitus, Type 2/blood
- Diabetes Mellitus, Type 2/chemically induced
- Diabetes Mellitus, Type 2/drug therapy
- Diabetes Mellitus, Type 2/genetics
- Diabetes Mellitus, Type 2/physiopathology
- Diet, High-Fat
- Eating/drug effects
- Feeding Behavior/drug effects
- Galanin/genetics
- Galanin/metabolism
- Hypoglycemic Agents/pharmacology
- Hypothalamus/drug effects
- Hypothalamus/metabolism
- Hypothalamus/physiopathology
- Insulin Detemir
- Insulin Glargine
- Insulin, Long-Acting/pharmacology
- Neuropeptide Y/metabolism
- Protein Precursors/genetics
- Protein Precursors/metabolism
- RNA, Messenger/metabolism
- Rats, Sprague-Dawley
- Streptozocin
- Weight Gain/drug effects
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Affiliation(s)
- Mohammad Ishraq Zafar
- Department of Endocrinology, Union Hospital, Tongji Medical College, Huazhong University of Science & Technology, 1277 Jiefang Avenue, Wuhan 430022, China
| | - Cuining Hu
- Department of Endocrinology, Union Hospital, Tongji Medical College, Huazhong University of Science & Technology, 1277 Jiefang Avenue, Wuhan 430022, China
| | - Danfeng Liu
- Department of Endocrinology, Union Hospital, Tongji Medical College, Huazhong University of Science & Technology, 1277 Jiefang Avenue, Wuhan 430022, China
| | - Raja Adeel Shafqat
- Department of Medicine, Tongji Hospital, Tongji Medical College, Huazhong University of Science & Technology, 1095 Jiefang Avenue, Wuhan 430030, China
| | - Feng Gao
- Department of Endocrinology, Union Hospital, Tongji Medical College, Huazhong University of Science & Technology, 1277 Jiefang Avenue, Wuhan 430022, China
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Betke KM, Rose KL, Friedman DB, Baucum AJ, Hyde K, Schey KL, Hamm HE. Differential localization of G protein βγ subunits. Biochemistry 2014; 53:2329-43. [PMID: 24568373 PMCID: PMC4004276 DOI: 10.1021/bi500091p] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022]
Abstract
G protein βγ subunits play essential roles in regulating cellular signaling cascades, yet little is known about their distribution in tissues or their subcellular localization. While previous studies have suggested specific isoforms may exhibit a wide range of distributions throughout the central nervous system, a thorough investigation of the expression patterns of both Gβ and Gγ isoforms within subcellular fractions has not been conducted. To address this, we applied a targeted proteomics approach known as multiple-reaction monitoring to analyze localization patterns of Gβ and Gγ isoforms in pre- and postsynaptic fractions isolated from cortex, cerebellum, hippocampus, and striatum. Particular Gβ and Gγ subunits were found to exhibit distinct regional and subcellular localization patterns throughout the brain. Significant differences in subcellular localization between pre- and postsynaptic fractions were observed within the striatum for most Gβ and Gγ isoforms, while others exhibited completely unique expression patterns in all four brain regions examined. Such differences are a prerequisite for understanding roles of individual subunits in regulating specific signaling pathways throughout the central nervous system.
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Affiliation(s)
- Katherine M Betke
- Department of Pharmacology, ‡Mass Spectrometry Research Center, §Department of Molecular Physiology and Biophysics, and ∥Department of Biochemistry, Vanderbilt University Medical Center , Nashville, Tennessee 37232-6600, United States
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Bartfai T, Wang MW. Positive allosteric modulators to peptide GPCRs: a promising class of drugs. Acta Pharmacol Sin 2013; 34:880-5. [PMID: 23624758 DOI: 10.1038/aps.2013.20] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/03/2012] [Accepted: 02/07/2013] [Indexed: 02/06/2023] Open
Abstract
The task of finding selective and stable peptide receptor agonists with low molecular weight, desirable pharmacokinetic properties and penetrable to the blood-brain barrier has proven too difficult for many highly coveted drug targets, including receptors for endothelin, vasoactive intestinal peptide and galanin. These receptors and ligand-gated ion channels activated by structurally simple agonists such as glutamate, glycine and GABA present such a narrow chemical space that the design of subtype-selective molecules capable of distinguishing a dozen of glutamate and GABA receptor subtypes and possessing desirable pharmacokinetic properties has also been problematic. In contrast, the pharmaceutical industry demonstrates a remarkable success in developing 1,4-benzodiazepines, positive allosteric modulators (PMAs) of the GABAA receptor. They were synthesized over 50 years ago and discovered to have anxiolytic potential through an in vivo assay. As exemplified by Librium, Valium and Dormicum, these allosteric ligands of the receptor became the world's first blockbuster drugs. Through molecular manipulation over the past 2 decades, including mutations and knockouts of the endogenous ligands or their receptors, and by in-depth physiological and pharmacological studies, more peptide and glutamate receptors have become well-validated drug targets for which an agonist is sought. In such cases, the pursuit for PAMs has also intensified, and a working paradigm to identify drug candidates that are designed as PAMs has emerged. This review, which focuses on the general principles of finding PAMs of peptide receptors in the 21st century, describes the workflow and some of its resulting compounds such as PAMs of galanin receptor 2 that act as potent anticonvulsant agents.
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