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Subedi KP, Timilsina S, Yadav KK, Shrestha S, Kansakar PBS. Jejunojejunal intussusception in an adult due to adenoma: a case report. J Surg Case Rep 2022; 2022:rjac343. [PMID: 35865257 PMCID: PMC9296136 DOI: 10.1093/jscr/rjac343] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/14/2022] [Accepted: 07/02/2022] [Indexed: 11/14/2022] Open
Abstract
Intussusception is a rare condition in adults and presents a diagnostic challenge. Clinical presentation tends to be chronic and non-specific. Unlike the pediatric population, most adult intussusceptions have structural lesions as lead points. Here, we present a case of jejunojejunal intussusception in a 27-year female due to adenoma of small bowel.
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Affiliation(s)
- Krishna P Subedi
- Maharajgunj Medical Campus, Institute of Medicine , Kathmandu 44600 , Nepal
| | - Shashank Timilsina
- Maharajgunj Medical Campus, Institute of Medicine , Kathmandu 44600 , Nepal
| | | | - Suraj Shrestha
- Maharajgunj Medical Campus, Institute of Medicine , Kathmandu 44600 , Nepal
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2
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Liu X, Subedi KP, Zheng C, Ambudkar I. Author Correction: Mitochondria-targeted antioxidant protects against irradiation-induced salivary gland hypofunction. Sci Rep 2021; 11:14593. [PMID: 34253826 PMCID: PMC8275585 DOI: 10.1038/s41598-021-94087-7] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/01/2022] Open
Affiliation(s)
- Xibao Liu
- Secretory Physiology Section, National Institute of Dental and Craniofacial Research, NIH, 9000 Rockville Pike, Bethesda, MD, 20892, USA
| | - Krishna P Subedi
- Secretory Physiology Section, National Institute of Dental and Craniofacial Research, NIH, 9000 Rockville Pike, Bethesda, MD, 20892, USA
| | - Changyu Zheng
- Secretory Physiology Section, National Institute of Dental and Craniofacial Research, NIH, 9000 Rockville Pike, Bethesda, MD, 20892, USA
| | - Indu Ambudkar
- Secretory Physiology Section, National Institute of Dental and Craniofacial Research, NIH, 9000 Rockville Pike, Bethesda, MD, 20892, USA. .,NIH, Building 10, Room 1N‑113, Bethesda, MD, 20892, USA.
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Liu X, Subedi KP, Zheng C, Ambudkar I. Mitochondria-targeted antioxidant protects against irradiation-induced salivary gland hypofunction. Sci Rep 2021; 11:7690. [PMID: 33833270 PMCID: PMC8032724 DOI: 10.1038/s41598-021-86927-3] [Citation(s) in RCA: 14] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/28/2020] [Accepted: 03/10/2021] [Indexed: 12/02/2022] Open
Abstract
A severe consequence of radiation therapy in patients with head and neck cancer is persistent salivary gland hypofunction which causes xerostomia and oral infections. We previously showed that irradiation (IR) of salivary glands in mice triggers initial transient increases in mitochondrial reactive oxygen species (ROSmt), mitochondrial [Ca2+] ([Ca2+]mt), and activated caspase-3 in acinar cells. In contrast, loss of salivary secretion is persistent. Herein we assessed the role of ROSmt in radiation-induced irreversible loss of salivary gland function. We report that treatment of mice with the mitochondrial-targeted antioxidant, MitoTEMPO, resulted in almost complete protection of salivary gland secretion following either single (15 Gy) or fractionated (5 × 3 Gy) doses of irradiation. Salivary gland cells isolated from MitoTEMPO-treated, irradiated, mice displayed significant attenuation of the initial increases in ROSmt, ([Ca2+]mt, and activated caspase-3 as compared to cells from irradiated, but untreated, animals. Importantly, MitoTEMPO treatment prevented radiation-induced decrease in STIM1, consequently protecting store-operated Ca2+ entry which is critical for saliva secretion. Together, these findings identify the initial increase in ROSmt, that is induced by irradiation, as a critical driver of persistent salivary gland hypofunction. We suggest that the mitochondrially targeted antioxidant, MitoTEMPO, can be potentially important in preventing IR-induced salivary gland dysfunction.
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Affiliation(s)
- Xibao Liu
- Secretory Physiology Section, National Institute of Dental and Craniofacial Research, NIH, 9000 Rockville Pike, Bethesda, MD, 20892, USA
| | - Krishna P Subedi
- Secretory Physiology Section, National Institute of Dental and Craniofacial Research, NIH, 9000 Rockville Pike, Bethesda, MD, 20892, USA
| | - Changyu Zheng
- Secretory Physiology Section, National Institute of Dental and Craniofacial Research, NIH, 9000 Rockville Pike, Bethesda, MD, 20892, USA
| | - Indu Ambudkar
- Secretory Physiology Section, National Institute of Dental and Craniofacial Research, NIH, 9000 Rockville Pike, Bethesda, MD, 20892, USA. .,NIH, Building 10, Room 1N-113, Bethesda, MD, 20892, USA.
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Emrich SM, Yoast RE, Xin P, Zhang X, Pathak T, Nwokonko R, Gueguinou MF, Subedi KP, Zhou Y, Ambudkar IS, Hempel N, Machaca K, Gill DL, Trebak M. Cross-talk between N-terminal and C-terminal domains in stromal interaction molecule 2 (STIM2) determines enhanced STIM2 sensitivity. J Biol Chem 2019; 294:6318-6332. [PMID: 30824535 DOI: 10.1074/jbc.ra118.006801] [Citation(s) in RCA: 25] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/17/2018] [Revised: 02/28/2019] [Indexed: 12/20/2022] Open
Abstract
Store-operated Ca2+ entry (SOCE) is a ubiquitous pathway for Ca2+ influx across the plasma membrane (PM). SOCE is mediated by the endoplasmic reticulum (ER)-associated Ca2+-sensing proteins stromal interaction molecule 1 (STIM1) and STIM2, which transition into an active conformation in response to ER Ca2+ store depletion, thereby interacting with and gating PM-associated ORAI1 channels. Although structurally homologous, STIM1 and STIM2 generate distinct Ca2+ signatures in response to varying strengths of agonist stimulation. The physiological functions of these Ca2+ signatures, particularly under native conditions, remain unclear. To investigate the structural properties distinguishing STIM1 and STIM2 activation of ORAI1 channels under native conditions, here we used CRISPR/Cas9 to generate STIM1-/-, STIM2-/-, and STIM1/2-/- knockouts in HEK293 and colorectal HCT116 cells. We show that depending on cell type, STIM2 can significantly sustain SOCE in response to maximal store depletion. Utilizing the SOCE modifier 2-aminoethoxydiphenyl borate (2-APB), we demonstrate that 2-APB-activated store-independent Ca2+ entry is mediated exclusively by endogenous STIM2. Using variants that either stabilize or disrupt intramolecular interactions of STIM C termini, we show that the increased flexibility of the STIM2 C terminus contributes to its selective store-independent activation by 2-APB. However, STIM1 variants with enhanced flexibility in the C terminus failed to support its store-independent activation. STIM1/STIM2 chimeric constructs indicated that coordination between N-terminal sensitivity and C-terminal flexibility is required for specific store-independent STIM2 activation. Our results clarify the structural determinants underlying activation of specific STIM isoforms, insights that are potentially useful for isoform-selective drug targeting.
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Affiliation(s)
- Scott M Emrich
- From the Departments of Cellular and Molecular Physiology and
| | - Ryan E Yoast
- From the Departments of Cellular and Molecular Physiology and
| | - Ping Xin
- From the Departments of Cellular and Molecular Physiology and
| | - Xuexin Zhang
- From the Departments of Cellular and Molecular Physiology and
| | | | - Robert Nwokonko
- From the Departments of Cellular and Molecular Physiology and
| | | | - Krishna P Subedi
- the Secretory Physiology Section, NIDCR, National Institutes of Health, Bethesda, Maryland 20892, and
| | - Yandong Zhou
- From the Departments of Cellular and Molecular Physiology and
| | - Indu S Ambudkar
- the Secretory Physiology Section, NIDCR, National Institutes of Health, Bethesda, Maryland 20892, and
| | - Nadine Hempel
- Pharmacology, Pennsylvania State University College of Medicine, Hershey, Pennsylvania 17033
| | - Khaled Machaca
- the Department of Physiology and Biophysics, Weill Cornell Medical College in Qatar, Education City, Qatar Foundation, P.O. Box 24144, Doha, Qatar
| | - Donald L Gill
- From the Departments of Cellular and Molecular Physiology and
| | - Mohamed Trebak
- From the Departments of Cellular and Molecular Physiology and
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Liu X, Gong B, de Souza LB, Ong HL, Subedi KP, Cheng KT, Swaim W, Zheng C, Mori Y, Ambudkar IS. Radiation inhibits salivary gland function by promoting STIM1 cleavage by caspase-3 and loss of SOCE through a TRPM2-dependent pathway. Sci Signal 2017; 10:10/482/eaal4064. [PMID: 28588080 DOI: 10.1126/scisignal.aal4064] [Citation(s) in RCA: 35] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/09/2023]
Abstract
Store-operated Ca2+ entry (SOCE) is critical for salivary gland fluid secretion. We report that radiation treatment caused persistent salivary gland dysfunction by activating a TRPM2-dependent mitochondrial pathway, leading to caspase-3-mediated cleavage of stromal interaction molecule 1 (STIM1) and loss of SOCE. After irradiation, acinar cells from the submandibular glands of TRPM2+/+ , but not those from TRPM2-/- mice, displayed an increase in the concentrations of mitochondrial Ca2+ and reactive oxygen species, a decrease in mitochondrial membrane potential, and activation of caspase-3, which was associated with a sustained decrease in STIM1 abundance and attenuation of SOCE. In a salivary gland cell line, silencing the mitochondrial Ca2+ uniporter or caspase-3 or treatment with inhibitors of TRPM2 or caspase-3 prevented irradiation-induced loss of STIM1 and SOCE. Expression of exogenous STIM1 in the salivary glands of irradiated mice increased SOCE and fluid secretion. We suggest that targeting the mechanisms underlying the loss of STIM1 would be a potentially useful approach for preserving salivary gland function after radiation therapy.
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Affiliation(s)
- Xibao Liu
- Molecular Physiology and Therapeutics Branch, National Institute of Dental and Craniofacial Research, National Institutes of Health, Bethesda, MD 20892, USA
| | - Baijuan Gong
- Department of Orthodontics, Jilin University School of Stomatology, Changchun 130021, People's Republic of China
| | - Lorena Brito de Souza
- Molecular Physiology and Therapeutics Branch, National Institute of Dental and Craniofacial Research, National Institutes of Health, Bethesda, MD 20892, USA
| | - Hwei Ling Ong
- Molecular Physiology and Therapeutics Branch, National Institute of Dental and Craniofacial Research, National Institutes of Health, Bethesda, MD 20892, USA
| | - Krishna P Subedi
- Molecular Physiology and Therapeutics Branch, National Institute of Dental and Craniofacial Research, National Institutes of Health, Bethesda, MD 20892, USA
| | - Kwong Tai Cheng
- Molecular Physiology and Therapeutics Branch, National Institute of Dental and Craniofacial Research, National Institutes of Health, Bethesda, MD 20892, USA
| | - William Swaim
- Molecular Physiology and Therapeutics Branch, National Institute of Dental and Craniofacial Research, National Institutes of Health, Bethesda, MD 20892, USA
| | - Changyu Zheng
- Molecular Physiology and Therapeutics Branch, National Institute of Dental and Craniofacial Research, National Institutes of Health, Bethesda, MD 20892, USA
| | - Yasuo Mori
- Laboratory of Molecular Biology, Department of Synthetic and Biological Chemistry, Graduate School of Engineering, Kyoto University, Kyoto 615-8510, Japan
| | - Indu S Ambudkar
- Molecular Physiology and Therapeutics Branch, National Institute of Dental and Craniofacial Research, National Institutes of Health, Bethesda, MD 20892, USA.
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6
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Subedi KP, Son MJ, Chidipi B, Kim SW, Wang J, Kim KH, Woo SH, Kim JC. Signaling Pathway for Endothelin-1- and Phenylephrine-Induced cAMP Response Element Binding Protein Activation in Rat Ventricular Myocytes: Role of Inositol 1,4,5-Trisphosphate Receptors and CaMKII. Cell Physiol Biochem 2017; 41:399-412. [PMID: 28214885 DOI: 10.1159/000456422] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/05/2016] [Accepted: 12/02/2016] [Indexed: 01/23/2023] Open
Abstract
BACKGROUND/AIMS Endothelin-1 (ET-1) and the α<Sub>1</Sub>-adrenoceptor agonist phenylephrine (PE) activate cAMP response element binding protein (CREB), a transcription factor implicated in cardiac hypertrophy. The signaling pathway involved in CREB activation by these hypertrophic stimuli is poorly understood. We examined signaling pathways for ET-1- or PE-induced cardiac CREB activation. METHODS Western blotting was performed with pharmacological and genetic interventions in rat ventricular myocytes. RESULTS ET-1 and PE increased CREB phosphorylation, which was inhibited by blockade of phospholipase C, the extracellular-signal-regulated kinase 1/2 (ERK1/2) pathway, protein kinase C (PKC) or Ca2+-calmodulin-dependent protein kinase II (CaMKII). Intracellular Ca2+ buffering decreased ET-1- and PE-induced CREB phosphorylation by ≥80%. Sarcoplasmic reticulum Ca2+ pump inhibitor, inositol 1,4,5-trisphosphate receptor (IP<Sub>3</Sub>R) blockers, or type 2 IP<Sub>3</Sub>R (IP<Sub>3</Sub>R2) knock-out abolished ET-1- or PE-induced CREB phosphorylation. ET-1 and PE increased phosphorylation of CaMKII and ERK1/2, which was eliminated by IP<Sub>3</Sub>R blockade/knock-out or PKC inhibition. Activation of CaMKII, but not ERK1/2, by these agonists was sensitive to Ca2+ buffering or to Gö6976, the inhibitor of Ca2+-dependent PKC and protein kinase D (PKD). CONCLUSION CREB phosphorylation by ET-1 and PE may be mainly mediated by IP<Sub>3</Sub>R2/Ca2+-PKC-PKD-CaMKII signaling with a minor contribution by ERK1/2, linked to IP<Sub>3</Sub>R2 and Ca2+-independent PKC, in ventricular myocytes.
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MESH Headings
- Animals
- Calcium-Calmodulin-Dependent Protein Kinase Type 2/metabolism
- Carbazoles/pharmacology
- Cells, Cultured
- Cyclic AMP Response Element-Binding Protein/metabolism
- Endothelin-1/pharmacology
- Flavonoids/pharmacology
- Inositol 1,4,5-Trisphosphate Receptors/deficiency
- Inositol 1,4,5-Trisphosphate Receptors/genetics
- Inositol 1,4,5-Trisphosphate Receptors/metabolism
- Male
- Mice
- Mice, Inbred C57BL
- Mice, Knockout
- Mitogen-Activated Protein Kinase 1/metabolism
- Mitogen-Activated Protein Kinase 3/metabolism
- Myocytes, Cardiac/cytology
- Myocytes, Cardiac/metabolism
- Phenylephrine/pharmacology
- Phosphorylation/drug effects
- Protein Kinase C/antagonists & inhibitors
- Protein Kinase C/metabolism
- Rats
- Rats, Sprague-Dawley
- Signal Transduction/drug effects
- Type C Phospholipases/antagonists & inhibitors
- Type C Phospholipases/metabolism
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7
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Abstract
Store-operated calcium entry (SOCE), a unique plasma membrane Ca2+ entry mechanism, is activated when ER-[Ca2+] is decreased. SOCE is mediated via the primary channel, Orai1, as well as others such as TRPC1. STIM1 and STIM2 are ER-Ca2+ sensor proteins that regulate Orai1 and TRPC1. SOCE requires assembly of STIM proteins with the plasma membrane channels which occurs within distinct regions in the cell that have been termed as endoplasmic reticulum (ER)-plasma membrane (PM) junctions. The PM and ER are in close proximity to each other within this region, which allows STIM1 in the ER to interact with and activate either Orai1 or TRPC1 in the plasma membrane. Activation and regulation of SOCE involves dynamic assembly of various components that are involved in mediating Ca2+ entry as well as those that determine the formation and stabilization of the junctions. These components include proteins in the cytosol, ER and PM, as well as lipids in the PM. Recent studies have also suggested that SOCE and its components are compartmentalized within ER-PM junctions and that this process might require remodeling of the plasma membrane lipids and reorganization of structural and scaffolding proteins. Such compartmentalization leads to the generation of spatially- and temporally-controlled Ca2+signals that are critical for regulating many downstream cellular functions.
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Affiliation(s)
- Krishna P Subedi
- Secretory Physiology Section, Molecular Physiology and Therapeutics Branch, NIDCR, NIH, Bethesda, MD, USA
| | - Hwei Ling Ong
- Secretory Physiology Section, Molecular Physiology and Therapeutics Branch, NIDCR, NIH, Bethesda, MD, USA
| | - Indu S Ambudkar
- Secretory Physiology Section, Molecular Physiology and Therapeutics Branch, NIDCR, NIH, Bethesda, MD, USA.
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8
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Son MJ, Kim JC, Kim SW, Chidipi B, Muniyandi J, Singh TD, So I, Subedi KP, Woo SH. Shear stress activates monovalent cation channel transient receptor potential melastatin subfamily 4 in rat atrial myocytes via type 2 inositol 1,4,5-trisphosphate receptors and Ca(2+) release. J Physiol 2016; 594:2985-3004. [PMID: 26751048 DOI: 10.1113/jp270887] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/07/2015] [Accepted: 01/06/2016] [Indexed: 12/22/2022] Open
Abstract
KEY POINTS During each contraction and haemodynamic disturbance, cardiac myocytes are subjected to fluid shear stress as a result of blood flow and the relative movement of sheets of myocytes. The present study aimed to characterize the shear stress-sensitive membrane current in atrial myocytes using the whole-cell patch clamp technique, combined with pressurized fluid flow, as well as pharmacological and genetic interventions of specific proteins. The data obtained suggest that shear stress indirectly activates the monovalent cation current carried by transient receptor potential melastatin subfamily 4 channels via type 2 inositol 1,4,5-trisphosphate receptor-mediated Ca(2+) release in subsarcolemmal domains of atrial myocytes. Ca(2+) -mediated interactions between these two proteins under shear stress may be an important mechanism by which atrial cells measure mechanical stress and translate it to alter their excitability. ABSTRACT Atrial myocytes are subjected to shear stress during the cardiac cycle under physiological or pathological conditions. The ionic currents regulated by shear stress remain poorly understood. We report the characteristics, molecular identity and activation mechanism of the shear stress-sensitive current (Ishear ) in rat atrial myocytes. A shear stress of ∼16 dyn cm(-2) was applied to single myocytes using a pressurized microflow system, and the current was measured by whole-cell patch clamp. In symmetrical CsCl solutions with minimal concentrations of internal EGTA, Ishear showed an outwardly rectifying current-voltage relationship (reversal at -2 mV). The current was conducted primarily (∼80%) by monovalent cations but not Ca(2+) . It was suppressed by intracellular Ca(2+) buffering at a fixed physiological level, inhibitors of transient receptor potential melastatin subfamily 4 (TRPM4), intracellular introduction of TRPM4 antibodies or knockdown of TRPM4 expression, suggesting that TRPM4 carries most of this current. A notable reduction in Ishear occurred upon inhibition of Ca(2+) release through the ryanodine receptors or inositol 1,4,5-trisphosphate receptors (IP3 R) and upon depletion of sarcoplasmic reticulum Ca(2+) . In type 2 IP3 R (IP3 R2) knockout atrial myocytes, Ishear was 10-20% of that in wild-type myocytes. Immunocytochemistry and proximity ligation assays revealed that TRPM4 and IP3 R2 were expressed at peripheral sites with co-localization, although they are not localized within 40 nm. Peripheral localization of TRPM4 was intact in IP3 R2 knockout cells. The data obtained in the present study suggest that shear stress activates TRPM4 current by triggering Ca(2+) release from the IP3 R2 in the peripheral domains of atrial myocytes.
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Affiliation(s)
- Min-Jeong Son
- Laboratory of Physiology, College of Pharmacy, Chungnam National University, Yuseong-gu, Daejeon, South Korea
| | - Joon-Chul Kim
- Laboratory of Physiology, College of Pharmacy, Chungnam National University, Yuseong-gu, Daejeon, South Korea
| | - Sung Woo Kim
- Laboratory of Physiology, College of Pharmacy, Chungnam National University, Yuseong-gu, Daejeon, South Korea
| | - Bojjibabu Chidipi
- Laboratory of Physiology, College of Pharmacy, Chungnam National University, Yuseong-gu, Daejeon, South Korea
| | - Jeyaraj Muniyandi
- Laboratory of Physiology, College of Pharmacy, Chungnam National University, Yuseong-gu, Daejeon, South Korea
| | - Thoudam Debraj Singh
- Laboratory of Physiology, College of Pharmacy, Chungnam National University, Yuseong-gu, Daejeon, South Korea
| | - Insuk So
- Department of Physiology, College of Medicine, Seoul National University, Seoul, South Korea
| | - Krishna P Subedi
- Laboratory of Physiology, College of Pharmacy, Chungnam National University, Yuseong-gu, Daejeon, South Korea.,Secretory Physiology Section, Molecular Physiology and Therapeutics Branch, National Institute of Dental and Craniofacial Research, NIH, Bethesda, MD, USA
| | - Sun-Hee Woo
- Laboratory of Physiology, College of Pharmacy, Chungnam National University, Yuseong-gu, Daejeon, South Korea
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9
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Huang C, Hu J, Subedi KP, Lin AHY, Paudel O, Ran P, Sham JSK. Extracellular Adenosine Diphosphate Ribose Mobilizes Intracellular Ca2+ via Purinergic-Dependent Ca2+ Pathways in Rat Pulmonary Artery Smooth Muscle Cells. Cell Physiol Biochem 2015; 37:2043-59. [PMID: 26584302 DOI: 10.1159/000438564] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [MESH Headings] [Grants] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 10/19/2015] [Indexed: 11/19/2022] Open
Abstract
BACKGROUND/AIMS Adenosine diphosphate ribose (ADPR), a product of β-NAD+ metabolism generated by the multifunctional enzyme CD38, is recognized as a novel signaling molecule. The catalytic site of CD38 orients extracellularly or intracellularly, capable of generating ADPR outside and inside the cells. CD38-dependent pathways have been characterized in pulmonary artery smooth muscle cells (PASMCs); however the physiological function of extracellular ADPR is unclear. METHODS Ca2+ mobilizing and proliferative effects of extracellular ADPR were characterized and compared with the ATP-induced responses in rat PASMCs; and the expression of purinergic receptor (P2X and P2Y) subtypes were examined in pulmonary arteries. RESULTS ADPR elicited concentration-dependent increase in [Ca2+]i with a fast transient and a sustained phase in PASMCs. The sustained phase was abolished by Ca2+ removal and inhibited by the non-selective cation channel blocker SKF-96365, but was unaffected by TRPM2 antagonists or nifedipine. The purinergic receptor (P2X) antagonist pyridoxal-phosphate-6-azophenyl-2', 4'-disulfonate inhibited partially the transient and the sustained Ca2+ response, while the P2(XY) inhibitor suramin and the phospholipase C inhibitor U73122 abolished the sustained Ca2+ influx. The P2Y1 antagonist MRS2179 had no effect on the response. By contrast, ATP and ADP activated Ca2+ response exhibited a high and a low affinity component, and the pharmacological profile of ATP-induced Ca2+ response was distinctive from that of ADPR. BrdU incorporation assay showed that ADPR caused significant inhibition whereas ATP caused slight stimulation of PASMC proliferation. RT-PCR analysis found that almost all P2X and P2Y subtypes are expressed in PAs. CONCLUSION ADPR and ATP activate Ca2+ responses through different combinations of multiple purinergic receptor subtypes; and extracellular ADPR may exert an autocrine/paracrine action via purinergic receptors on PASMCs.
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MESH Headings
- Adenosine Diphosphate Ribose/pharmacology
- Adenosine Triphosphate/pharmacology
- Animals
- Calcium/metabolism
- Calcium Signaling/drug effects
- Cells, Cultured
- Estrenes/pharmacology
- Imidazoles/pharmacology
- Ions/chemistry
- Ions/metabolism
- Male
- Myocytes, Smooth Muscle/cytology
- Myocytes, Smooth Muscle/drug effects
- Myocytes, Smooth Muscle/metabolism
- Nifedipine/pharmacology
- Pulmonary Artery/cytology
- Pulmonary Artery/metabolism
- Purinergic P2X Receptor Antagonists/pharmacology
- Purinergic P2Y Receptor Antagonists/pharmacology
- Pyrrolidinones/pharmacology
- Rats
- Rats, Wistar
- Receptors, Purinergic P2X/chemistry
- Receptors, Purinergic P2X/genetics
- Receptors, Purinergic P2X/metabolism
- Receptors, Purinergic P2Y1/chemistry
- Receptors, Purinergic P2Y1/genetics
- Receptors, Purinergic P2Y1/metabolism
- Signal Transduction/drug effects
- Suramin/pharmacology
- TRPM Cation Channels/metabolism
- Type C Phospholipases/antagonists & inhibitors
- Type C Phospholipases/metabolism
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10
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Subedi KP, Paudel O, Sham JSK. Detection of differentially regulated subsarcolemmal calcium signals activated by vasoactive agonists in rat pulmonary artery smooth muscle cells. Am J Physiol Cell Physiol 2013; 306:C659-69. [PMID: 24352334 DOI: 10.1152/ajpcell.00341.2013] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
Intracellular calcium (Ca(2+)) plays pivotal roles in distinct cellular functions through global and local signaling in various subcellular compartments, and subcellular Ca(2+) signal is the key factor for independent regulation of different cellular functions. In vascular smooth muscle cells, subsarcolemmal Ca(2+) is an important regulator of excitation-contraction coupling, and nucleoplasmic Ca(2+) is crucial for excitation-transcription coupling. However, information on Ca(2+) signals in these subcellular compartments is limited. To study the regulation of the subcellular Ca(2+) signals, genetically encoded Ca(2+) indicators (cameleon), D3cpv, targeting the plasma membrane (PM), cytoplasm, and nucleoplasm were transfected into rat pulmonary arterial smooth muscle cells (PASMCs) and Ca(2+) signals were monitored using laser scanning confocal microscopy. In situ calibration showed that the Kd for Ca(2+) of D3cpv was comparable in the cytoplasm and nucleoplasm, but it was slightly higher in the PM. Stimulation of digitonin-permeabilized cells with 1,4,5-trisphosphate (IP3) elicited a transient elevation of Ca(2+) concentration with similar amplitude and kinetics in the nucleoplasm and cytoplasm. Activation of G protein-coupled receptors by endothelin-1 and angiotensin II preferentially elevated the subsarcolemmal Ca(2+) signal with higher amplitude in the PM region than the nucleoplasm and cytoplasm. In contrast, the receptor tyrosine kinase activator, platelet-derived growth factor, elicited Ca(2+) signals with similar amplitudes in all three regions, except that the rise-time and decay-time were slightly slower in the PM region. These data clearly revealed compartmentalization of Ca(2+) signals in the subsarcolemmal regions and provide the basis for further investigations of differential regulation of subcellular Ca(2+) signals in PASMCs.
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Affiliation(s)
- Krishna P Subedi
- Division of Pulmonary and Critical Care Medicine, Department of Medicine, Johns Hopkins University School of Medicine, Baltimore, Maryland
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11
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Bilukha OO, Becknell K, Laurenge H, Danee L, Subedi KP. Fatal and non-fatal injuries due to intentional explosions in Nepal, 2008-2011: analysis of surveillance data. Confl Health 2013; 7:5. [PMID: 23514664 PMCID: PMC3606620 DOI: 10.1186/1752-1505-7-5] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/27/2012] [Accepted: 03/16/2013] [Indexed: 11/21/2022] Open
Abstract
Background Nepal is one of the post-conflict countries affected by violence from explosive devices. We undertook this study to assess the magnitude of injuries due to intentional explosions in Nepal during 2008-2011 and to describe time trends and epidemiologic patterns for these events. Methods We analyzed surveillance data on fatal and non-fatal injuries due to intentional explosions in Nepal that occurred between 1 January 2008 and 31 December 2011. The case definition included casualties injured or killed by explosive devices knowingly activated by an individual or a group of individuals with the intent to harm, hurt or terrorize. Data were collected through media-based and active community-based surveillance. Results Analysis included 437 casualties injured or killed in 131 intentional explosion incidents. A decrease in the number of incidents and casualties between January 2008 and June 2009 was followed by a pronounced increase between July 2010 and June 2011. Eighty-four (19.2%) casualties were among females and 40 (9.2%) were among children under 18 years of age. Fifty-nine (45.3%) incidents involved one casualty, 47 (35.9%) involved 2 to 4 casualties, and 6 involved more than 10 casualties. The overall case-fatality ratio was 7.8%. The highest numbers of incidents occurred in streets or at crossroads, in victims’ homes, and in shops or markets. Incidents on buses and near stadiums claimed the highest numbers of casualties per incident. Socket, sutali, and pressure cooker bombs caused the highest numbers of incidents. Conclusions Intentional explosion incidents still pose a threat to the civilian population of Nepal. Most incidents are caused by small homemade explosive devices and occur in public places, and males aged 20 to 39 account for a plurality of casualties. Stakeholders addressing the explosive device problem in Nepal should continue to use surveillance data to plan interventions.
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Affiliation(s)
- Oleg O Bilukha
- International Emergency and Refugee Health Branch, Center for Global Health, Centers for Disease Control and Prevention, 4770 Buford Hwy, MS F-60, Atlanta, GA, 30341, USA.
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Subedi KP, Singh TD, Kim JC, Woo SH. Cloning and expression of a new inositol 1,4,5-trisphosphate receptor type 1 splice variant in adult rat atrial myocytes. Cell Mol Biol Lett 2012; 17:124-35. [PMID: 22207335 PMCID: PMC6275638 DOI: 10.2478/s11658-011-0043-7] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/21/2011] [Accepted: 12/16/2011] [Indexed: 11/20/2022] Open
Abstract
Inositol 1,4,5-trisphosphate receptor type 1 (IP(3)R1) is already known to be highly expressed in the brain, and is found in many other tissues, including the atrium of the heart. Although the complete primary structure of IP(3)R1 in the rat brain has been reported, the complete sequence of an IP(3)R1 clone from atrial myocytes has not been reported. We isolated an IP(3)R1 complementary DNA (cDNA) clone from isolated adult rat atrial myocytes, and found a new splice variant of IP(3)R1 that was different from a previously reported IP(3)R1 cDNA clone obtained from a rat brain (NCBI GenBank accession number: NM_001007235). Our clone had 99% similarity with the rat brain IP(3)R1 sequence; the exceptions were 39 amino acid deletions at the position of 1693-1731, and the deletion of phenylalanine at position 1372 that lay in the regulatory region. Compared with the rat brain IP(3)R1, in our clone proline was replaced with serine at residue 2439, and alanine was substituted for valine at residue 2445. These changes lie adjacent to or within the fifth transmembrane domain (2440-2462). Although such changes in the amino acid sequences were different from the rat brain IP3R1 clone, they were conserved in human or mouse IP3R1. We produced a plasmid construct expressing the atrial IP3R1 together with green fluorescent protein (GFP), and successfully overexpressed the atrial IP3R1 in the adult atrial cell line HL-1. Further investigation is needed on the physiological significance of the new splice variant in atrial cell function.
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Affiliation(s)
- Krishna P. Subedi
- College of Pharmacy, IDRD, Chungnam National University, 220 Gung-dong, Yuseong-gu, Daejeon, 305-764 South Korea
| | - Thoudam Debraj Singh
- College of Pharmacy, IDRD, Chungnam National University, 220 Gung-dong, Yuseong-gu, Daejeon, 305-764 South Korea
| | - Joon-Chul Kim
- College of Pharmacy, IDRD, Chungnam National University, 220 Gung-dong, Yuseong-gu, Daejeon, 305-764 South Korea
| | - Sun-Hee Woo
- College of Pharmacy, IDRD, Chungnam National University, 220 Gung-dong, Yuseong-gu, Daejeon, 305-764 South Korea
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Kim JC, Son MJ, Subedi KP, Kim DH, Woo SH. IP3-induced cytosolic and nuclear Ca2+ signals in HL-1 atrial myocytes: possible role of IP3 receptor subtypes. Mol Cells 2010; 29:387-95. [PMID: 20213315 DOI: 10.1007/s10059-010-0039-6] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/28/2009] [Revised: 11/30/2009] [Accepted: 12/07/2009] [Indexed: 10/19/2022] Open
Abstract
HL-1 cells are the adult cardiac cell lines available that continuously divide while maintaining an atrial phenotype. Here we examined the expression and localization of inositol 1,4,5-trisphosphate receptor (IP(3)R) subtypes, and investigated how pattern of IP(3)-induced subcellular local Ca(2+) signaling is encoded by multiple IP(3)R subtypes in HL-1 cells. The type 1 IP(3)R (IP(3)R1) was expressed in the perinucleus with a diffuse pattern and the type 2 IP(3)R (IP(3)R2) was expressed in the cytosol with a punctate distribution. Extracellular ATP (1 mM) elicited transient intracellular Ca(2+) releases accompanied by a Ca(2+) oscillation, which was eliminated by the blocker of IP(3)Rs, 2-APB, and attenuated by ryanodine. Direct introduction of IP(3) into the permeabilized cells induced Ca(2+) transients with Ca(2+) oscillations at [Symbol: see text] 20 muM of IP(3), which was removed by the inhibition of IP(3)Rs using 2-APB and heparin. IP(3)-induced local Ca(2+) transients contained two distinct time courses: a rapid oscillation and a monophasic Ca(2+) transient. The magnitude of Ca(2+) oscillation was significantly larger in the cytosol than in the nucleus, while the monophasic Ca(2+) transient was more pronounced in the nucleus. These results provide evidence for the molecular and functional expression of IP(3)R1 and IP(3)R2 in HL-1 cells, and suggest that such distinct local Ca(2+) signaling may be correlated with the punctate distribution of IP(3)R2s in the cytosol and the diffuse localization of IP(3)R1 in the peri-nucleus.
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MESH Headings
- Adenosine Triphosphate/pharmacology
- Animals
- Blotting, Western
- Calcium/metabolism
- Calcium Signaling/drug effects
- Cell Line
- Cell Nucleus/metabolism
- Cells, Cultured
- Cytosol/metabolism
- Dose-Response Relationship, Drug
- Heart Atria/cytology
- Immunohistochemistry
- Inositol 1,4,5-Trisphosphate/pharmacology
- Inositol 1,4,5-Trisphosphate Receptors/genetics
- Inositol 1,4,5-Trisphosphate Receptors/metabolism
- Inositol 1,4,5-Trisphosphate Receptors/physiology
- Male
- Mice
- Microscopy, Confocal
- Myocytes, Cardiac/cytology
- Myocytes, Cardiac/drug effects
- Myocytes, Cardiac/metabolism
- Protein Isoforms/genetics
- Protein Isoforms/metabolism
- Protein Isoforms/physiology
- Rats
- Rats, Sprague-Dawley
- Reverse Transcriptase Polymerase Chain Reaction
- Time Factors
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Affiliation(s)
- Joon-Chul Kim
- College of Pharmacy, IDRD, Chungnam National University, Daejeon, 305-764, Korea
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Kim JC, Son MJ, Subedi KP, Woo SH. IP3-induced Ca2+ Signals at the Cytoplasm and Nucleus in HL-1 Atrial Cells: Possible Roles of IP3 Receptor Subtypes. Biophys J 2009. [DOI: 10.1016/j.bpj.2008.12.2791] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022] Open
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Subedi KP, Kim I, Kim J, Min B, Park C. Role of GldA in dihydroxyacetone and methylglyoxal metabolism ofEscherichia coliK12. FEMS Microbiol Lett 2008; 279:180-7. [DOI: 10.1111/j.1574-6968.2007.01032.x] [Citation(s) in RCA: 40] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022] Open
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