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Kang Y, Saito M, Toyoda H. Molecular and Regulatory Mechanisms of Desensitization and Resensitization of GABA A Receptors with a Special Reference to Propofol/Barbiturate. Int J Mol Sci 2020; 21:ijms21020563. [PMID: 31952324 PMCID: PMC7014398 DOI: 10.3390/ijms21020563] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/25/2019] [Revised: 01/11/2020] [Accepted: 01/14/2020] [Indexed: 11/16/2022] Open
Abstract
It is known that desensitization of GABAA receptor (GABAAR)-mediated currents is paradoxically correlated with the slowdown of their deactivation, i.e., resensitization. It has been shown that an upregulation of calcineurin enhances the desensitization of GABAAR-mediated currents but paradoxically prolongs the decay phase of inhibitory postsynaptic currents/potentials without appreciable diminution of their amplitudes. The paradoxical correlation between desensitization and resensitization of GABAAR-mediated currents can be more clearly seen in response to a prolonged application of GABA to allow more desensitization, instead of brief pulse used in previous studies. Indeed, hump-like GABAAR currents were produced after a strong desensitization at the offset of a prolonged puff application of GABA in pyramidal cells of the barrel cortex, in which calcineurin activity was enhanced by deleting phospholipase C-related catalytically inactive proteins to enhance the desensitization/resensitization of GABAAR-mediated currents. Hump-like GABAAR currents were also evoked at the offset of propofol or barbiturate applications in hippocampal or sensory neurons, but not GABA applications. Propofol and barbiturate are useful to treat benzodiazepine/alcohol withdrawal syndrome, suggesting that regulatory mechanisms of desensitization/resensitization of GABAAR-mediated currents are important in understanding benzodiazepine/alcohol withdrawal syndrome. In this review, we will discuss the molecular and regulatory mechanisms underlying the desensitization and resensitization of GABAAR-mediated currents and their functional significances.
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Affiliation(s)
- Youngnam Kang
- Department of Behavioral Physiology, Graduate School of Human Sciences, Osaka University, Osaka 565-0871, Japan
- Department of Neurobiology and Physiology, School of Dentistry, Seoul National University, Seoul 110-749, Korea
- Correspondence: (Y.K.); (H.T.)
| | - Mitsuru Saito
- Department of Oral Physiology, Graduate School of Medical and Dental Sciences, Kagoshima University, Sakuragaoka 8-35-1, Kagoshima 890-8544, Japan;
| | - Hiroki Toyoda
- Department of Neuroscience and Oral Physiology, Osaka University Graduate School of Dentistry, Osaka 565-0871, Japan
- Correspondence: (Y.K.); (H.T.)
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General anesthetic actions on GABA A receptors in vivo are reduced in phospholipase C-related catalytically inactive protein knockout mice. J Anesth 2017; 31:531-538. [PMID: 28389811 DOI: 10.1007/s00540-017-2350-2] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/04/2016] [Accepted: 03/26/2017] [Indexed: 10/19/2022]
Abstract
PURPOSE The aim of this study was to investigate the action of general anesthetics in phospholipase C-related catalytically inactive protein (PRIP)-knockout (KO) mice that alter GABAA receptor signaling. METHODS PRIP regulates the intracellular trafficking of β subunit-containing GABAA receptors in vitro. In this study, we examined the effects of intravenous anesthetics, propofol and etomidate that act via β subunit-containing GABAA receptors, in wild-type and Prip-KO mice. Mice were intraperitoneally injected with a drug, and a loss of righting reflex (LORR) assay and an electroencephalogram analysis were performed. RESULTS The cell surface expression of GABAA receptor β3 subunit detected by immunoblotting was decreased in Prip-knockout brain compared with that in wild-type brain without changing the expression of other GABAA receptor subunits. Propofol-treated Prip-KO mice exhibited significantly shorter duration of LORR and had lower total anesthetic score than wild-type mice in the LORR assay. The average duration of sleep time in an electroencephalogram analysis was shorter in propofol-treated Prip-KO mice than in wild-type mice. The hypnotic action of etomidate was also reduced in Prip-KO mice. However, ketamine, an NMDA receptor antagonist, had similar effects in the two genotypes. CONCLUSION PRIP regulates the cell surface expression of the GABAA receptor β3 subunit and modulates general anesthetic action in vivo. Elucidation of the involved regulatory mechanisms of GABAA receptor-dependent signaling would inform the development of safer anesthetic therapies for clinical applications.
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Yamawaki Y, Oue K, Shirawachi S, Asano S, Harada K, Kanematsu T. Phospholipase C-related catalytically inactive protein can regulate obesity, a state of peripheral inflammation. JAPANESE DENTAL SCIENCE REVIEW 2016; 53:18-24. [PMID: 28408965 PMCID: PMC5390332 DOI: 10.1016/j.jdsr.2016.06.001] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/27/2016] [Revised: 05/23/2016] [Accepted: 06/06/2016] [Indexed: 11/28/2022] Open
Abstract
Obesity is defined as abnormal or excessive fat accumulation. Chronic inflammation in fat influences the development of obesity-related diseases. Many reports state that obesity increases the risk of morbidity in many diseases, including hypertension, dyslipidemia, type 2 diabetes, coronary heart disease, stroke, sleep apnea, and breast, prostate and colon cancers, leading to increased mortality. Obesity is also associated with chronic neuropathologic conditions such as depression and Alzheimer's disease. However, there is strong evidence that weight loss reduces these risks, by limiting blood pressure and improving levels of serum triglycerides, total cholesterol, low-density lipoprotein (LDL)-cholesterol, and high-density lipoprotein (HDL)-cholesterol. Prevention and control of obesity is complex, and requires a multifaceted approach. The elucidation of molecular mechanisms driving fat metabolism (adipogenesis and lipolysis) aims at developing clinical treatments to control obesity. We recently reported a new regulatory mechanism in fat metabolism: a protein phosphatase binding protein, phospholipase C-related catalytically inactive protein (PRIP), regulates lipolysis in white adipocytes and heat production in brown adipocytes via phosphoregulation. Deficiency of PRIP in mice led to reduced fat accumulation and increased energy expenditure, resulting in a lean phenotype. Here, we evaluate PRIP as a new therapeutic target for the control of obesity.
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Affiliation(s)
- Yosuke Yamawaki
- Department of Cellular and Molecular Pharmacology, Division of Basic Life Sciences, Institute of Biomedical and Health Sciences, Hiroshima University, Hiroshima 734-8553, Japan
| | - Kana Oue
- Department of Cellular and Molecular Pharmacology, Division of Basic Life Sciences, Institute of Biomedical and Health Sciences, Hiroshima University, Hiroshima 734-8553, Japan.,Department of Dental Anesthesiology, Division of Applied Life Sciences, Institute of Biomedical and Health Sciences, Hiroshima University, Hiroshima 734-8553, Japan
| | - Satomi Shirawachi
- Department of Cellular and Molecular Pharmacology, Division of Basic Life Sciences, Institute of Biomedical and Health Sciences, Hiroshima University, Hiroshima 734-8553, Japan
| | - Satoshi Asano
- Department of Cellular and Molecular Pharmacology, Division of Basic Life Sciences, Institute of Biomedical and Health Sciences, Hiroshima University, Hiroshima 734-8553, Japan
| | - Kae Harada
- Department of Cellular and Molecular Pharmacology, Division of Basic Life Sciences, Institute of Biomedical and Health Sciences, Hiroshima University, Hiroshima 734-8553, Japan
| | - Takashi Kanematsu
- Department of Cellular and Molecular Pharmacology, Division of Basic Life Sciences, Institute of Biomedical and Health Sciences, Hiroshima University, Hiroshima 734-8553, Japan
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Okumura T, Harada K, Oue K, Zhang J, Asano S, Hayashiuchi M, Mizokami A, Tanaka H, Irifune M, Kamata N, Hirata M, Kanematsu T. Phospholipase C-related catalytically inactive protein (PRIP) regulates lipolysis in adipose tissue by modulating the phosphorylation of hormone-sensitive lipase. PLoS One 2014; 9:e100559. [PMID: 24945349 PMCID: PMC4064000 DOI: 10.1371/journal.pone.0100559] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/29/2013] [Accepted: 05/28/2014] [Indexed: 01/15/2023] Open
Abstract
Phosphorylation of hormone-sensitive lipase (HSL) and perilipin by protein kinase A (PKA) promotes the hydrolysis of lipids in adipocytes. Although activation of lipolysis by PKA has been well studied, inactivation via protein phosphatases is poorly understood. Here, we investigated whether phospholipase C-related catalytically inactive protein (PRIP), a binding partner for protein phosphatase 1 and protein phosphatase 2A (PP2A), is involved in lipolysis by regulating phosphatase activity. PRIP knockout (PRIP-KO) mice displayed reduced body-fat mass as compared with wild-type mice fed with standard chow ad libitum. Most other organs appeared normal, suggesting that mutant mice had aberrant fat metabolism in adipocytes. HSL in PRIP-KO adipose tissue was highly phosphorylated compared to that in wild-type mice. Starvation of wild-type mice or stimulation of adipose tissue explants with the catabolic hormone, adrenaline, translocated both PRIP and PP2A from the cytosol to lipid droplets, but the translocation of PP2A was significantly reduced in PRIP-KO adipocytes. Consistently, the phosphatase activity associated with lipid droplet fraction in PRIP-KO adipocytes was significantly reduced and was independent of adrenaline stimulation. Lipolysis activity, as assessed by measurement of non-esterified fatty acids and glycerol, was higher in PRIP-KO adipocytes. When wild-type adipocytes were treated with a phosphatase inhibitor, they showed a high lipolysis activity at the similar level to PRIP-KO adipocytes. Collectively, these results suggest that PRIP promotes the translocation of phosphatases to lipid droplets to trigger the dephosphorylation of HSL and perilipin A, thus reducing PKA-mediated lipolysis.
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Affiliation(s)
- Toshiya Okumura
- Department of Cellular and Molecular Pharmacology, Institute of Biomedical and Health Sciences, Hiroshima University, Hiroshima, Japan
- Department of Oral Surgery, Institute of Biomedical and Health Sciences, Hiroshima University, Hiroshima, Japan
| | - Kae Harada
- Department of Cellular and Molecular Pharmacology, Institute of Biomedical and Health Sciences, Hiroshima University, Hiroshima, Japan
| | - Kana Oue
- Department of Cellular and Molecular Pharmacology, Institute of Biomedical and Health Sciences, Hiroshima University, Hiroshima, Japan
- Department of Dental Anesthesiology, Institute of Biomedical and Health Sciences, Hiroshima University, Hiroshima, Japan
| | - Jun Zhang
- Department of Cellular and Molecular Pharmacology, Institute of Biomedical and Health Sciences, Hiroshima University, Hiroshima, Japan
| | - Satoshi Asano
- Department of Cellular and Molecular Pharmacology, Institute of Biomedical and Health Sciences, Hiroshima University, Hiroshima, Japan
| | - Masaki Hayashiuchi
- Department of Cellular and Molecular Pharmacology, Institute of Biomedical and Health Sciences, Hiroshima University, Hiroshima, Japan
| | - Akiko Mizokami
- Laboratory of Molecular and Cellular Biochemistry, Faculty of Dental Science, Kyushu University, Fukuoka, Japan
| | - Hiroto Tanaka
- Department of Cellular and Molecular Pharmacology, Institute of Biomedical and Health Sciences, Hiroshima University, Hiroshima, Japan
- Laboratory of Molecular and Cellular Biochemistry, Faculty of Dental Science, Kyushu University, Fukuoka, Japan
| | - Masahiro Irifune
- Department of Dental Anesthesiology, Institute of Biomedical and Health Sciences, Hiroshima University, Hiroshima, Japan
| | - Nobuyuki Kamata
- Department of Oral Surgery, Institute of Biomedical and Health Sciences, Hiroshima University, Hiroshima, Japan
| | - Masato Hirata
- Laboratory of Molecular and Cellular Biochemistry, Faculty of Dental Science, Kyushu University, Fukuoka, Japan
| | - Takashi Kanematsu
- Department of Cellular and Molecular Pharmacology, Institute of Biomedical and Health Sciences, Hiroshima University, Hiroshima, Japan
- * E-mail:
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Toyoda H, Saito M, Sato H, Tanaka T, Ogawa T, Yatani H, Kawano T, Kanematsu T, Hirata M, Kang Y. Enhanced desensitization followed by unusual resensitization in GABAA receptors in phospholipase C-related catalytically inactive protein-1/2 double-knockout mice. Pflugers Arch 2014; 467:267-84. [PMID: 24737248 DOI: 10.1007/s00424-014-1511-5] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/22/2014] [Revised: 03/24/2014] [Accepted: 03/27/2014] [Indexed: 11/29/2022]
Abstract
Phospholipase C-related catalytically inactive proteins (PRIP-1/2) are previously reported to be involved in the membrane trafficking of GABAA receptor (GABAAR) and the regulation of intracellular Ca(2+) stores. GABAAR-mediated currents can be regulated by the intracellular Ca(2+). However, in PRIP-1/2 double-knockout (PRIP-DKO) mice, it remains unclear whether the kinetic properties of GABAARs are modulated by the altered regulation of intracellular Ca(2+) stores. Here, we investigated whether GABAAR currents (IGABA) evoked by GABA puff in layer 3 (L3) pyramidal cells (PCs) of the barrel cortex are altered in PRIP-DKO mice. The deletion of PRIP-1/2 enhanced the desensitization of IGABA but induced a hump-like tail current (tail-I) at the GABA puff offset. IGABA and the hump-like tail-I were suppressed by GABAAR antagonists. The enhanced desensitization of IGABA and the hump-like tail-I in PRIP-DKO PCs were mediated by increases in the intracellular Ca(2+) concentration and were largely abolished by a calcineurin inhibitor and ruthenium red. Calcium imaging revealed that Ca(2+)-induced Ca(2+) release (CICR) and subsequent store-operated Ca(2+) entry (SOCE) are more potent in PRIP-DKO PCs than in wild-type PCs. A mathematical model revealed that a slowdown of GABA-unbinding rate and an acceleration of fast desensitization rate by enhancing its GABA concentration dependency are involved in the generation of hump-like tail-Is. These results suggest that in L3 PCs of the barrel cortex in PRIP-DKO mice, the increased calcineurin activity due to the potentiated CICR and SOCE enhances the desensitization of GABAARs and slows the GABA-unbinding rate, resulting in their unusual resensitization following removal of GABA.
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Affiliation(s)
- Hiroki Toyoda
- Department of Neuroscience and Oral Physiology, Osaka University Graduate School of Dentistry, 1-8, Yamadaoka, Suita, Osaka, 565-0871, Japan
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Tsutsumi K, Matsuda M, Kotani M, Mizokami A, Murakami A, Takahashi I, Terada Y, Kanematsu T, Fukami K, Takenawa T, Jimi E, Hirata M. Involvement of PRIP, phospholipase C-related, but catalytically inactive protein, in bone formation. J Biol Chem 2011; 286:31032-31042. [PMID: 21757756 PMCID: PMC3162462 DOI: 10.1074/jbc.m111.235903] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/01/2011] [Revised: 07/08/2011] [Indexed: 11/06/2022] Open
Abstract
PRIP (phospholipase C-related, but catalytically inactive protein) is a novel protein isolated in this laboratory. PRIP-deficient mice showed increased serum gonadotropins, but decreased gonadal steroid hormones. This imbalance was similar to that for the cause of bone disease, such as osteoporosis. In the present study, therefore, we analyzed mutant mice with special reference to the bone property. We first performed three-dimensional analysis of the femur of female mice. The bone mineral density and trabecular bone volume were higher in mutant mice. We further performed histomorphometrical assay of bone formation parameters: bone formation rate, mineral apposition rate, osteoid thickness, and osteoblast number were up-regulated in the mutant, indicating that increased bone mass is caused by the enhancement of bone formation ability. We then cultured primary cells isolated from calvaria prepared from both genotypes. In mutant mice, osteoblast differentiation, as assessed by alkaline phosphatase activity and the expression of osteoblast differentiation marker genes, was enhanced. Moreover, we analyzed the phosphorylation of Smad1/5/8 in response to bone morphogenetic protein, with longer phosphorylation in the mutant. These results indicate that PRIP is implicated in the negative regulation of bone formation.
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Affiliation(s)
- Koshiro Tsutsumi
- Laboratory of Molecular and Cellular Biochemistry, Kyushu University, Fukuoka 812-8582, Japan; Division of Fixed Prosthodontics, Kyushu University, Fukuoka 812-8582, Japan
| | - Miho Matsuda
- Laboratory of Molecular and Cellular Biochemistry, Kyushu University, Fukuoka 812-8582, Japan
| | - Miho Kotani
- Laboratory of Molecular and Cellular Biochemistry, Kyushu University, Fukuoka 812-8582, Japan; Division of Orthodontics, Faculty of Dental Science, Kyushu University, Fukuoka 812-8582, Japan
| | - Akiko Mizokami
- Laboratory of Molecular and Cellular Biochemistry, Kyushu University, Fukuoka 812-8582, Japan
| | - Ayako Murakami
- Division of Orthodontics, Faculty of Dental Science, Kyushu University, Fukuoka 812-8582, Japan
| | - Ichiro Takahashi
- Division of Orthodontics, Faculty of Dental Science, Kyushu University, Fukuoka 812-8582, Japan
| | - Yoshihiro Terada
- Division of Fixed Prosthodontics, Kyushu University, Fukuoka 812-8582, Japan
| | - Takashi Kanematsu
- Laboratory of Molecular and Cellular Biochemistry, Kyushu University, Fukuoka 812-8582, Japan
| | - Kiyoko Fukami
- Laboratory of Genome and Biosignal, Tokyo University of Pharmacy and Life Science, Tokyo 192-0392, Japan
| | - Tadaomi Takenawa
- Division of Lipid Biochemistry, Graduate School of Medicine, Kobe University, Kobe 650-0017, Japan
| | - Eijiro Jimi
- Department of Molecular Signaling and Biochemistry, Kyushu Dental College, Kitakyushu 803-8580, Japan
| | - Masato Hirata
- Laboratory of Molecular and Cellular Biochemistry, Kyushu University, Fukuoka 812-8582, Japan.
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