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Wei W, Tang LWT, Verma RK, Fan H, Chan ECY. Probe Substrate Dependencies in CYP3A4 Allosteric Inhibition: A Novel Molecular Mechanism Involving F-F' Loop Perturbations. J Chem Inf Model 2024; 64:2058-2067. [PMID: 38457234 DOI: 10.1021/acs.jcim.3c01837] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 03/09/2024]
Abstract
The biochemical basis for substrate dependences in apparent inhibition constant values (Ki) remains unknown. Our study aims to elucidate plausible structural determinants underpinning these observations. In vitro steady-state inhibition assays conducted using human recombinant CYP3A4 enzyme and testosterone substrate revealed that fibroblast growth factor receptor (FGFR) inhibitors erdafitinib and pemigatinib noncompetitively inhibited CYP3A4 with apparent Ki values of 10.2 ± 1.1 and 3.3 ± 0.9 μM, respectively. However, when rivaroxaban was adopted as the probe substrate, there were 2.0- and 3.2-fold decreases in its apparent Ki values. To glean mechanistic insights into this phenomenon, erdafitinib and pemigatinib were docked to allosteric sites in CYP3A4. Subsequently, molecular dynamics (MD) simulations of apo- and holo-CYP3A4 were conducted to investigate the structural changes induced. Comparative structural analyses of representative MD frames extracted by hierarchical clustering revealed that the allosteric inhibition of CYP3A4 by erdafitinib and pemigatinib did not substantially modulate its active site characteristics. In contrast, we discovered that allosteric binding of the FGFR inhibitors reduces the structural flexibility of the F-F' loop region, an important gating mechanism to regulate access of the substrate to the catalytic heme. We surmised that the increased rigidity of the F-F' loop engenders a more constrained entrance to the CYP3A4 active site, which in turn impedes access to the larger rivaroxaban molecule to a greater extent than testosterone and culminates in more potent inhibition of its CYP3A4-mediated metabolism. Our findings suggest a potential mechanism to rationalize probe substrate dependencies in Ki arising from the allosteric noncompetitive inhibition of CYP3A4.
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Affiliation(s)
- Wan Wei
- Bioinformatics Institute (BII), Agency for Science, Technology and Research (A*STAR), 30 Biopolis Street, 138671 Singapore
| | - Lloyd Wei Tat Tang
- Department of Pharmacy, Faculty of Science, National University of Singapore, 18 Science Drive 4, 117543 Singapore
| | - Ravi Kumar Verma
- Bioinformatics Institute (BII), Agency for Science, Technology and Research (A*STAR), 30 Biopolis Street, 138671 Singapore
| | - Hao Fan
- Bioinformatics Institute (BII), Agency for Science, Technology and Research (A*STAR), 30 Biopolis Street, 138671 Singapore
| | - Eric Chun Yong Chan
- Department of Pharmacy, Faculty of Science, National University of Singapore, 18 Science Drive 4, 117543 Singapore
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Tang LWT, Wei W, Verma RK, Koh SK, Zhou L, Fan H, Chan ECY. Direct and Sequential Bioactivation of Pemigatinib to a Reactive Iminium Ion Intermediate Culminates in Mechanism‐Based Inactivation of Cytochrome P450 3A. FASEB J 2022. [DOI: 10.1096/fasebj.2022.36.s1.0r684] [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] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Affiliation(s)
| | - Wan Wei
- Bioinformatics Institute (BII), Agency for Science, Technology and Research (A*STAR)Singapore
| | - Ravi Kumar Verma
- Bioinformatics Institute (BII), Agency for Science, Technology and Research (A*STAR)Singapore
| | | | - Lei Zhou
- Singapore Eye Research Institute (SERI)Singapore
| | - Hao Fan
- Bioinformatics Institute (BII), Agency for Science, Technology and Research (A*STAR)Singapore
| | - Eric Chun Yong Chan
- PharmacyDepartment of PharmacyFaculty of Science, National University of SingaporeSingapore
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Tang LWT, Wei W, Verma RK, Koh SK, Zhou L, Fan H, Chan ECY. Direct and Sequential Bioactivation of Pemigatinib to Reactive Iminium Ion Intermediates Culminate in Mechanism-Based Inactivation of Cytochrome P450 3A. Drug Metab Dispos 2022; 50:529-540. [DOI: 10.1124/dmd.121.000804] [Citation(s) in RCA: 7] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/06/2021] [Accepted: 02/01/2022] [Indexed: 11/22/2022] Open
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Singh Y, Yadav AK, Bajpai V, Diwedi P, Verma S, Verma RK. Comparison of intrathecal fentanyl and buprenorphine as adjuvants to bupivacaine in gynecological surgery. Anaesth pain intensive care 2022. [DOI: 10.35975/apic.v26i1.1764] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
Abstract
Background & Objective: Hyperbaric bupivacaine is the most commonly used local anesthetic for spinal anesthesia, alone or in combination with various adjuvants. Opioids are frequently used for their rapid onset and intense block characteristics. Fentanyl is the preferred intrathecal opioids with rapid onset of action but has a shorter duration of action. Buprenorphine is a mixed agonist-antagonist with high affinity at both mu and kappa opioid receptors. We compared administration of buprenorphine with fentanyl as adjuvants with intrathecal hyperbaric bupivacaine in gynecological surgeries.
Methodology: After Institutional Ethical Committee approval and written informed consent, 60 patients aged 18–65 y, scheduled for lower abdominal gynecological surgery, were divided into two equal groups; Group F to receive 0.5% hyperbaric bupivacaine 2.5 ml with fentanyl 25 µg intrathecal and Group B to receive 0.5% hyperbaric bupivacaine 2.5 ml with buprenorphine 75 µg intrathecal. Block characteristics and associated side effects were compared between two groups. The data was analyzed using Chi square test and Fisher’s exact test. For comparing two group of mean, independent student’s t test was used. P-value < 0.05 was considered as statistically significant.
Results: The mean onset of sensory and motor block was significantly earlier in Group F than Group B (p < 0.001). Mean duration of sensory block was significantly prolonged in Group B compared to Group F (p < 0.05). Whereas, the duration of motor was comparable in both of the groups (p > 0.05). Duration of analgesia was significantly prolonged in Group B than Group F (p < 0.001).
Conclusion: We conclude that when a longer duration of postoperative pain relief is needed, buprenorphine can be a suitable drug to be used with intrathecal hyperbaric bupivacaine for gynecological surgeries because of prolonged duration of action.
Key words: Spinal anesthesia; Fentanyl; Buprenorphine; Bupivacaine
Citation: Singh Y, Yadav AK, Vijeta Bajpai, Diwedi P, Verma S, Verma RK. Comparison of intrathecal fentanyl and buprenorphine as adjuvants to bupivacaine in gynecological surgery. Anaesth. pain intensive care 2021;26(1):39-43.
DOI: 10.35975/apic.v26i1.1764
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Goel M, Kumar A, Maitra G, Verma RK. First report of trans-mediastinal perforation of bilateral main bronchi by a self-expandable metallic stent. Lung India 2022; 39:201-202. [PMID: 35259807 PMCID: PMC9053922 DOI: 10.4103/lungindia.lungindia_720_21] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022] Open
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Shukla P, Loha S, Verma RK. Comparative Efficacy of Addition of Fentanyl and Neostigmine to Isobaric 0.75% Ropivacaine in Elderly Patients undergoing Transurethral Resection of Prostate under Spinal Anaesthesia: A Double-blinded Randomised Clinical Study. J Clin Diagn Res 2022. [DOI: 10.7860/jcdr/2022/57705.17078] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Abstract
Introduction: Ropivacaine is a well-accepted local anaesthetic drug used in spinal and peripheral nerve blocks.It provides a better central nervous system and cardiovascular stability in comparison to bupivacaine. Adjuvants are also added with these drugs as they provide haemodynamic stability, increase efficacy, and decrease the dose requirement of the local anaesthetic drugs. Aim: To determine the efficacy of isobaric 0.75% ropivacaine in combination with normal saline, fentanyl, and neostigmine in Elderly Patients Undergoing Transurethral Resection of Prostate Under Spinal Anaesthesia. Materials and Methods: This double-blinded randomised clinical study conducted in the Department of Anaesthesiology and Critical Care, Institute of Medical Sciences-Banaras Hindu University, Varanasi, Uttar Pradesh, India, from July 2018 to June 2019. The study included 90 patients who were divided into three groups of 30 subjects each. Ropivacaine combined with normal saline in group RNS, ropivacaine combined with fentanyl in group RFE and ropivacaine combined with neostigmine in group RNE, was administered intrathecally.Heart rate, respiratory rate, blood pressure, onset and duration of sensory and motor block, along with the duration of analgesia, were recorded at different time points. The Analysis Of Variance (ANOVA) was used to compare the variables among the three study groups, and Student-Newman-Keuls was used to compare the data between the groups. Results: Patients in group RNE showed a significant fall in heart rate in comparison to groups RNS and RFE at all the time points. Respiratory rate followed a similar pattern in group RNE (p-value <0.001), except at 5 min and 90 min. Mean systolic blood pressure showed a significant rise in group RNE compared to the other two groups, while diastolic blood pressure followed a similar trend at 10, 20, 30, and 60 min. The SpO2 (%) was comparable among groups. The onset of sensory loss was significantly earlier in group RNE (239.6±28.8 sec) than in groups RNS (298.1±27.8 sec), and RFE (261.9±32.2 sec). The duration of the sensory block was significantly longer in group RFE (227.8±30.5 min). The mean time to the onset of motor block (480.7±30.2 sec) and analgesia (582.33±30.2 min) was longer in group RNE than in other groups. Conclusion: The addition of neostigmine to ropivacaine intrathecally is a reliable method to prolong spinal anaesthesia but close monitoring of vitals is desirable.
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Krishna Deepak RNV, Verma RK, Hartono YD, Yew WS, Fan H. Recent Advances in Structure, Function, and Pharmacology of Class A Lipid GPCRs: Opportunities and Challenges for Drug Discovery. Pharmaceuticals (Basel) 2021; 15:12. [PMID: 35056070 PMCID: PMC8779880 DOI: 10.3390/ph15010012] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/30/2021] [Revised: 12/17/2021] [Accepted: 12/17/2021] [Indexed: 01/01/2023] Open
Abstract
Great progress has been made over the past decade in understanding the structural, functional, and pharmacological diversity of lipid GPCRs. From the first determination of the crystal structure of bovine rhodopsin in 2000, much progress has been made in the field of GPCR structural biology. The extraordinary progress in structural biology and pharmacology of GPCRs, coupled with rapid advances in computational approaches to study receptor dynamics and receptor-ligand interactions, has broadened our comprehension of the structural and functional facets of the receptor family members and has helped usher in a modern age of structure-based drug design and development. First, we provide a primer on lipid mediators and lipid GPCRs and their role in physiology and diseases as well as their value as drug targets. Second, we summarize the current advancements in the understanding of structural features of lipid GPCRs, such as the structural variation of their extracellular domains, diversity of their orthosteric and allosteric ligand binding sites, and molecular mechanisms of ligand binding. Third, we close by collating the emerging paradigms and opportunities in targeting lipid GPCRs, including a brief discussion on current strategies, challenges, and the future outlook.
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Affiliation(s)
- R. N. V. Krishna Deepak
- Bioinformatics Institute, A*STAR, 30 Biopolis Street, Matrix #07-01, Singapore 138671, Singapore; (R.K.V.); (Y.D.H.)
| | - Ravi Kumar Verma
- Bioinformatics Institute, A*STAR, 30 Biopolis Street, Matrix #07-01, Singapore 138671, Singapore; (R.K.V.); (Y.D.H.)
| | - Yossa Dwi Hartono
- Bioinformatics Institute, A*STAR, 30 Biopolis Street, Matrix #07-01, Singapore 138671, Singapore; (R.K.V.); (Y.D.H.)
- Synthetic Biology Translational Research Programme, Yong Loo Lin School of Medicine, National University of Singapore, 14 Medical Drive, Singapore 117599, Singapore;
- Department of Biochemistry, Yong Loo Lin School of Medicine, National University of Singapore, 8 Medical Drive, Singapore 117597, Singapore
| | - Wen Shan Yew
- Synthetic Biology Translational Research Programme, Yong Loo Lin School of Medicine, National University of Singapore, 14 Medical Drive, Singapore 117599, Singapore;
- Department of Biochemistry, Yong Loo Lin School of Medicine, National University of Singapore, 8 Medical Drive, Singapore 117597, Singapore
| | - Hao Fan
- Bioinformatics Institute, A*STAR, 30 Biopolis Street, Matrix #07-01, Singapore 138671, Singapore; (R.K.V.); (Y.D.H.)
- Synthetic Biology Translational Research Programme, Yong Loo Lin School of Medicine, National University of Singapore, 14 Medical Drive, Singapore 117599, Singapore;
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Tang LWT, Teng JW, Verma RK, Koh SK, Zhou L, Go ML, Fan H, Chan ECY. Infigratinib is a Reversible Inhibitor and Mechanism-based Inactivator of Cytochrome P450 3A4. Drug Metab Dispos 2021; 49:856-868. [PMID: 34326139 DOI: 10.1124/dmd.121.000508] [Citation(s) in RCA: 9] [Impact Index Per Article: 3.0] [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: 04/19/2021] [Accepted: 07/08/2021] [Indexed: 11/22/2022] Open
Abstract
Infigratinib (INF) is a promising selective inhibitor of fibroblast growth factor receptors 1-3 that has recently been accorded both orphan drug designation and priority review status by the U.S Food and Drug Administration for the treatment of advanced cholangiocarcinoma. Its propensity to undergo bioactivation to electrophilic species was recently expounded upon. However, other than causing aberrant idiosyncratic toxicities, these reactive intermediates may elicit mechanism-based inactivation (MBI) of cytochrome P450 enzymes (CYP450). In this study, we investigated the interactions between INF and the most abundant hepatic cytochrome P450 3A4 (CYP3A4). Our findings revealed that apart from being a potent noncompetitive reversible inhibitor of CYP3A4, INF inactivated CYP3A4 in a time-, concentration- and NADPH-dependent manner with K I, k inact and partition ratio of 2.45 µM, 0.053 min-1 and 41 respectively when rivaroxaban was employed as the probe substrate. Co-incubation with testosterone (alternative CYP3A substrate) or ketoconazole (direct CYP3A inhibitor) attenuated the rate of inactivation whereas the inclusion of glutathione and catalase did not confer such protection. The lack of enzyme activity recovery following dialysis for 4 hours and oxidation with potassium ferricyanide, coupled with the absence of the characteristic Soret peak signature collectively substantiated that inactivation of CYP3A4 by INF was not mediated by the formation of quasi-irreversible metabolite-intermediate complexes but rather through irreversible covalent adduction to the prosthetic heme and/or apoprotein. Finally, glutathione trapping and high-resolution mass spectrometry experimental results unravelled two plausible bioactivation mechanisms of INF arising from the generation of a p-benzoquinone diimine and epoxide reactive intermediate. Significance Statement The potential of infigratinib (INF) to cause mechanism-based inactivation (MBI) of CYP3A4 was unknown. We report the reversible noncompetitive inhibition and irreversible covalent MBI of CYP3A4 by INF and proposed two potential bioactivation pathways implicating p-benzoquinone diimine and epoxide reactive intermediates. Findings from this study lay the groundwork for future investigation of clinically-relevant drug-drug interactions between INF and concomitant substrates of CYP3A4.
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Affiliation(s)
| | | | - Ravi Kumar Verma
- Bioinformatics Institute (BII), Agency for Science, Technology and Research (A*STAR), Singapore
| | | | - Lei Zhou
- Singapore Eye Research Institute, Singapore
| | - Mei Lin Go
- National University of Singapore, Singapore
| | - Hao Fan
- Bioinformatics Institute (BII), Agency for Science, Technology and Research (A*STAR), Singapore
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Tang LWT, Verma RK, Yong RP, Li X, Wang L, Lin Q, Fan H, Chan ECY. Differential Reversible and Irreversible Interactions between Benzbromarone and Human Cytochrome P450s 3A4 and 3A5. Mol Pharmacol 2021; 100:224-236. [PMID: 34210765 DOI: 10.1124/molpharm.121.000256] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/04/2021] [Accepted: 06/21/2021] [Indexed: 11/22/2022] Open
Abstract
Mounting evidence has revealed that despite the high degree of sequence homology between cytochrome P450 3A isoforms (i.e., CYP3A4 and CYP3A5), they have the propensities to exhibit vastly different irreversible and reversible interactions with a single substrate. We have previously established that benzbromarone (BBR), a potent uricosuric agent used in the management of gout, irreversibly inhibits CYP3A4 via mechanism-based inactivation (MBI). However, it remains unelucidated if CYP3A5-its highly homologous counterpart-is susceptible to inactivation by BBR. Using three structurally distinct probe substrates, we consistently demonstrated that MBI was not elicited in CYP3A5 by BBR. Our in silico covalent docking models and molecular dynamics simulations suggested that disparities in the susceptibilities toward MBI could be attributed to the specific effects of BBR covalent adducts on the F-F' loop. Serendipitously, we also discovered that BBR reversibly activated CYP3A5-mediated rivaroxaban hydroxylation wherein apparent V max increased and K m decreased with increasing BBR concentration. Fitting data to the two-site model yielded interaction factors α and β of 0.44 and 5.88, respectively, thereby confirming heterotropic activation of CYP3A5 by BBR. Furthermore, heteroactivation was suppressed by the CYP3A inhibitor ketoconazole in a concentration-dependent manner and decreased with increasing preincubation time, implying that activation was incited via binding of parent BBR molecule within the enzymatic active site. Finally, noncovalent docking revealed that CYP3A5 can more favorably accommodate both BBR and rivaroxaban in concert as compared with CYP3A4, which further substantiated our experimental observations. SIGNIFICANCE STATEMENT: Although it has been previously demonstrated that benzbromarone (BBR) inactivates CYP3A4, it remains uninterrogated whether it also elicits mechanism-based inactivation in CYP3A5, which shares ∼85% sequence similarity with CYP3A4. This study reported that BBR exhibited differential irreversible and reversible interactions with both CYP3A isoforms and further unraveled the molecular determinants underpinning their diverging interactions. These data offer important insight into differential kinetic behavior of CYP3A4 and CYP3A5, which potentially contributes to interindividual variabilities in drug disposition.
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Affiliation(s)
- Lloyd Wei Tat Tang
- Department of Pharmacy, Faculty of Science (L.W.T.T., R.P.Y., E.C.Y.C.), and Protein and Proteomics Centre (PPC), SingMass (X.L., L.W., Q.L.), National University of Singapore, Singapore; and Bioinformatics Institute (BII), Agency for Science, Technology and Research (A*STAR), Singapore (R.K.V., H.F.)
| | - Ravi Kumar Verma
- Department of Pharmacy, Faculty of Science (L.W.T.T., R.P.Y., E.C.Y.C.), and Protein and Proteomics Centre (PPC), SingMass (X.L., L.W., Q.L.), National University of Singapore, Singapore; and Bioinformatics Institute (BII), Agency for Science, Technology and Research (A*STAR), Singapore (R.K.V., H.F.)
| | - Ren Ping Yong
- Department of Pharmacy, Faculty of Science (L.W.T.T., R.P.Y., E.C.Y.C.), and Protein and Proteomics Centre (PPC), SingMass (X.L., L.W., Q.L.), National University of Singapore, Singapore; and Bioinformatics Institute (BII), Agency for Science, Technology and Research (A*STAR), Singapore (R.K.V., H.F.)
| | - Xin Li
- Department of Pharmacy, Faculty of Science (L.W.T.T., R.P.Y., E.C.Y.C.), and Protein and Proteomics Centre (PPC), SingMass (X.L., L.W., Q.L.), National University of Singapore, Singapore; and Bioinformatics Institute (BII), Agency for Science, Technology and Research (A*STAR), Singapore (R.K.V., H.F.)
| | - Lili Wang
- Department of Pharmacy, Faculty of Science (L.W.T.T., R.P.Y., E.C.Y.C.), and Protein and Proteomics Centre (PPC), SingMass (X.L., L.W., Q.L.), National University of Singapore, Singapore; and Bioinformatics Institute (BII), Agency for Science, Technology and Research (A*STAR), Singapore (R.K.V., H.F.)
| | - Qingsong Lin
- Department of Pharmacy, Faculty of Science (L.W.T.T., R.P.Y., E.C.Y.C.), and Protein and Proteomics Centre (PPC), SingMass (X.L., L.W., Q.L.), National University of Singapore, Singapore; and Bioinformatics Institute (BII), Agency for Science, Technology and Research (A*STAR), Singapore (R.K.V., H.F.)
| | - Hao Fan
- Department of Pharmacy, Faculty of Science (L.W.T.T., R.P.Y., E.C.Y.C.), and Protein and Proteomics Centre (PPC), SingMass (X.L., L.W., Q.L.), National University of Singapore, Singapore; and Bioinformatics Institute (BII), Agency for Science, Technology and Research (A*STAR), Singapore (R.K.V., H.F.)
| | - Eric Chun Yong Chan
- Department of Pharmacy, Faculty of Science (L.W.T.T., R.P.Y., E.C.Y.C.), and Protein and Proteomics Centre (PPC), SingMass (X.L., L.W., Q.L.), National University of Singapore, Singapore; and Bioinformatics Institute (BII), Agency for Science, Technology and Research (A*STAR), Singapore (R.K.V., H.F.)
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Trychta KA, Xie B, Verma RK, Xu M, Shi L, Harvey BK. Computational Modeling of C-Terminal Tails to Predict the Calcium-Dependent Secretion of Endoplasmic Reticulum Resident Proteins. Front Chem 2021; 9:689608. [PMID: 34268295 PMCID: PMC8276033 DOI: 10.3389/fchem.2021.689608] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/01/2021] [Accepted: 06/03/2021] [Indexed: 12/29/2022] Open
Abstract
The lumen of the endoplasmic reticulum (ER) has resident proteins that are critical to perform the various tasks of the ER such as protein maturation and lipid metabolism. These ER resident proteins typically have a carboxy-terminal ER retention/retrieval sequence (ERS). The canonical ERS that promotes ER retrieval is Lys-Asp-Glu-Leu (KDEL) and when an ER resident protein moves from the ER to the Golgi, KDEL receptors (KDELRs) in the Golgi recognize the ERS and return the protein to the ER lumen. Depletion of ER calcium leads to the mass departure of ER resident proteins in a process termed exodosis, which is regulated by KDELRs. Here, by combining computational prediction with machine learning-based models and experimental validation, we identify carboxy tail sequences of ER resident proteins divergent from the canonical “KDEL” ERS. Using molecular modeling and simulations, we demonstrated that two representative non-canonical ERS can stably bind to the KDELR. Collectively, we developed a method to predict whether a carboxy-terminal sequence acts as a putative ERS that would undergo secretion in response to ER calcium depletion and interacts with the KDELRs. The interaction between the ERS and the KDELR extends beyond the final four carboxy terminal residues of the ERS. Identification of proteins that undergo exodosis will further our understanding of changes in ER proteostasis under physiological and pathological conditions where ER calcium is depleted.
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Affiliation(s)
- Kathleen A Trychta
- Molecular Mechanisms of Cellular Stress and Inflammation Unit, National Institute on Drug Abuse, National Institutes of Health, Baltimore, MD, United States
| | - Bing Xie
- Computational Chemistry and Molecular Biophysics Section, National Institute on Drug Abuse, National Institutes of Health, Baltimore, MD, United States
| | - Ravi Kumar Verma
- Computational Chemistry and Molecular Biophysics Section, National Institute on Drug Abuse, National Institutes of Health, Baltimore, MD, United States
| | - Min Xu
- Computational Chemistry and Molecular Biophysics Section, National Institute on Drug Abuse, National Institutes of Health, Baltimore, MD, United States
| | - Lei Shi
- Computational Chemistry and Molecular Biophysics Section, National Institute on Drug Abuse, National Institutes of Health, Baltimore, MD, United States
| | - Brandon K Harvey
- Molecular Mechanisms of Cellular Stress and Inflammation Unit, National Institute on Drug Abuse, National Institutes of Health, Baltimore, MD, United States
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Leow JWH, Verma RK, Lim ABH, Fan H, Chan ECY. Atypical kinetics of cytochrome P450 2J2: Epoxidation of arachidonic acid and reversible inhibition by xenobiotic inhibitors. Eur J Pharm Sci 2021; 164:105889. [PMID: 34044117 DOI: 10.1016/j.ejps.2021.105889] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [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: 02/18/2021] [Revised: 05/04/2021] [Accepted: 05/20/2021] [Indexed: 01/08/2023]
Abstract
Extrahepatic CYP2J2 metabolism of arachidonic acid (AA) to bioactive regioisomeric epoxyeicosatrienoic acids (EETs) is implicated in both physiological and pathological conditions. Here, we aimed to characterize atypical substrate inhibition kinetics of this endogenous metabolic pathway and its reversible inhibition by xenobiotic inhibitors when AA is used as the physiologically-relevant substrate vis-à-vis conventional probe substrate astemizole (AST). As compared to typical Michaelis-Menten kinetics observed for AST, complete substrate inhibition was observed for CYP2J2 metabolism of AA to 14,15-EET whereby velocity of the reaction declined significantly at concentrations of AA above 20-30 µM with an estimated substrate inhibition constant (Ks) of 31 µM. In silico sequential docking of two AA substrates to orthosteric (OBS) and adjacent secondary binding sites (SBS) within a 3-dimensional homology model of CYP2J2 revealed favorable and comparable binding poses of glide-scores -3.1 and -3.8 respectively. Molecular dynamics (MD) simulations ascertained CYP2J2 conformational stability with dual AA substrate binding as time-dependent root mean squared deviation (RMSD) of protein Cα atoms and ligand heavy atoms stabilized to a plateau in all but one trajectory (n=6). The distance between heme-iron and ω6 (C14, C15) double bond of AA in OBS also increased from 7.5 ± 1.4 Å to 8.5 ± 1.8 Å when CYP2J2 was simulated with only AA in OBS versus the presence of AA in both OBS and SBS (p<0.001), supporting the observed in vitro substrate inhibition phenomenon. Poor correlation was observed between inhibitory constants (Ki) determined for a panel of nine competitive and mixed mode xenobiotic inhibitors against CYP2J2 metabolism of AA as compared to AST, whereby 4 out of 9 drugs had a greater than 5-fold difference between Ki values. Nonlinear Eadie-Hofstee plots illustrated that complete substrate inhibition of CYP2J2 by AA was not attenuated even at high concentrations of xenobiotic inhibitors which further corroborates that CYP2J2 may accommodate three or more ligands simultaneously. In light of the atypical kinetics, our results highlight the importance of using physiologically-relevant substrates in in vitro enzymatic inhibition assays for the characterization of xenobiotic-endobiotic interactions which is applicable to other complex endogenous metabolic pathways beyond CYP2J2 metabolism of AA to EETs. The accurate determination of Ki would further facilitate the association of xenobiotic-endobiotic interactions to observed therapeutic or toxic outcomes.
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Affiliation(s)
- Jacqueline Wen Hui Leow
- Department of Pharmacy, Faculty of Science, National University of Singapore, 18 Science Drive 4, Singapore 117543
| | - Ravi Kumar Verma
- Bioinformatics Institute (BII), Agency for Science, Technology and Research (A*STAR), 30 Biopolis Street, #07-01 Matrix, Singapore 138671
| | - Amos Boon Hao Lim
- Department of Pharmacy, Faculty of Science, National University of Singapore, 18 Science Drive 4, Singapore 117543
| | - Hao Fan
- Bioinformatics Institute (BII), Agency for Science, Technology and Research (A*STAR), 30 Biopolis Street, #07-01 Matrix, Singapore 138671
| | - Eric Chun Yong Chan
- Department of Pharmacy, Faculty of Science, National University of Singapore, 18 Science Drive 4, Singapore 117543.
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Tang LWT, Verma RK, Fan H, Chan ECY. Mechanism-Based Inactivation of Cytochrome P450 3A4 by Benzbromarone. Mol Pharmacol 2021; 99:266-276. [PMID: 33436520 DOI: 10.1124/molpharm.120.000086] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/10/2020] [Accepted: 12/31/2020] [Indexed: 12/14/2022] Open
Abstract
Benzbromarone (BBR), a potent uricosuric agent for the management of gout, is known to cause fatal fulminant hepatitis. Although the mechanism of BBR-induced idiosyncratic hepatotoxicity remains unelucidated, cytochrome P450 enzyme-mediated bioactivation of BBR to electrophilic reactive metabolites is commonly regarded as a key molecular initiating event. However, apart from causing aberrant toxicities, reactive metabolites may result in mechanism-based inactivation (MBI) of cytochrome P450. Here, we investigated and confirmed that BBR inactivated CYP3A4 in a time-, concentration-, and NADPH-dependent manner with K I, k inact, and partition ratio of 11.61 µM, 0.10 minutes-1, and 110, respectively. Coincubation with ketoconazole, a competitive inhibitor of CYP3A4, attenuated the MBI of CYP3A4 by BBR, whereas the presence of glutathione and catalase did not confer such protection. The lack of substantial recovery of enzyme activity postdialysis and after oxidation with potassium ferricyanide, combined with the absence of a Soret peak in spectral difference scans, implied that MBI of CYP3A4 by BBR did not occur through the formation of quasi-irreversible metabolite-intermediate complexes. Analysis of the reduced CO-difference spectrum revealed an ∼44% reduction in ferrous-CO binding and hinted that inactivation is mediated via irreversible covalent adduction to both the prosthetic heme moiety and the apoprotein. Finally, our in silico covalent docking analysis further suggested the modulation of substrate binding to CYP3A4 via the covalent adduction of epoxide-derived reactive intermediates of BBR to two key cysteine residues (Cys239 and Cys58) vicinal to the entrance of the orthosteric binding site. SIGNIFICANCE STATEMENT: Although the bioactivation of benzbromarone (BBR) to reactive metabolites has been well characterized, its potential to cause mechanism-based inactivation (MBI) of cytochrome P450 has not been fully investigated. This study reports the MBI of CYP3A4 by BBR via irreversible covalent adduction and develops a unique covalent docking methodology to predict the structural molecular determinants underpinning the inactivation for the first time. These findings lay the groundwork for future investigation of clinically relevant drug-drug interactions implicating BBR and mechanisms of BBR-induced idiosyncratic hepatotoxicity.
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Affiliation(s)
- Lloyd Wei Tat Tang
- Department of Pharmacy, Faculty of Science, National University of Singapore, Singapore (L.W.T.T., E.C.Y.C.) and Bioinformatics Institute (BII), Agency for Science, Technology and Research (A*STAR), Singapore (R.K.V., H.F.)
| | - Ravi Kumar Verma
- Department of Pharmacy, Faculty of Science, National University of Singapore, Singapore (L.W.T.T., E.C.Y.C.) and Bioinformatics Institute (BII), Agency for Science, Technology and Research (A*STAR), Singapore (R.K.V., H.F.)
| | - Hao Fan
- Department of Pharmacy, Faculty of Science, National University of Singapore, Singapore (L.W.T.T., E.C.Y.C.) and Bioinformatics Institute (BII), Agency for Science, Technology and Research (A*STAR), Singapore (R.K.V., H.F.)
| | - Eric Chun Yong Chan
- Department of Pharmacy, Faculty of Science, National University of Singapore, Singapore (L.W.T.T., E.C.Y.C.) and Bioinformatics Institute (BII), Agency for Science, Technology and Research (A*STAR), Singapore (R.K.V., H.F.)
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Goel MK, Kumar A, Maitra G, Singh B, Ahlawat S, Jain P, Garg N, Verma RK. Safety and diagnostic yield of transbronchial lung cryobiopsy by flexible bronchoscopy using laryngeal mask airway in diffuse and localized peripheral lung diseases: A single-center retrospective analysis of 326 cases. Lung India 2021; 38:109-116. [PMID: 33687002 PMCID: PMC8098897 DOI: 10.4103/lungindia.lungindia_220_20] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/04/2022] Open
Abstract
Background Intubation with either an endotracheal tube or a rigid bronchoscope is generally preferred to provide airway protection as well as to manage unpredictable complications during transbronchial lung cryobiopsy (TBLC). The laryngeal mask airway has been described as a safe and convenient tool for airway control during bronchoscopy. Aims and Objectives In this study, we evaluated the safety and outcome of using a laryngeal mask airway (LMA) as a conduit for performing TBLC by flexible video bronchoscopy (FB). Methods We retrospectively analyzed the database of the patients who underwent TBLC between November 2015 and September 2019. The procedure was performed using FB through LMA under general anesthesia. Prophylactic occlusion balloon was routinely used starting January 2017 onwards. Radial endobronchial ultrasound (R-EBUS) guidance was used for TBLC in the localized lung lesions when deemed necessary. Multidisciplinary consensus diagnostic yield was determined and periprocedural complications were recorded. Results A total of 326 patients were analysed. The overall diagnostic yield was 81.60% (266/326) which included a positive yield of 82.98% (161/194) in patients with diffuse lung disease and 79.54% (105/132) in patients with localized disease. Serious bleeding complication occurred in 3 (0.92%) cases. Pneumothorax was encountered in 8 (2.45%) cases. A total of 9 (2.76%) cases had at least 1 major complication. Conclusion This study demonstrates that the use of LMA during TBLC by flexible bronchoscopy allows for a convenient port of entry, adequate airway support and effective endoscopic management of intrabronchial haemorrhage especially with the use of occlusion balloon.
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Affiliation(s)
- Manoj Kumar Goel
- Department of Pulmonology, Critical Care and Sleep Medicine, Fortis Memorial Research Institute, Gurugram, Haryana, India
| | - Ajay Kumar
- Department of Pulmonology, Critical Care and Sleep Medicine, Fortis Memorial Research Institute, Gurugram, Haryana, India
| | - Gargi Maitra
- Department of Pulmonology, Critical Care and Sleep Medicine, Fortis Memorial Research Institute, Gurugram, Haryana, India
| | - Balkar Singh
- Department of Anesthesiology, Fortis Memorial Research Institute, Gurugram, Haryana, India
| | - Sunita Ahlawat
- Department of Pathology, Fortis Memorial Research Institute, Gurugram, Haryana, India
| | - Priti Jain
- Department of Pathology, Fortis Memorial Research Institute, Gurugram, Haryana, India
| | - Neeraj Garg
- Department of Pathology, Fortis Memorial Research Institute, Gurugram, Haryana, India
| | - R K Verma
- Department of Radiology, Fortis Memorial Research Institute, Gurugram, Haryana, India
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Moritz AE, Bonifazi A, Guerrero AM, Kumar V, Free RB, Lane JR, Verma RK, Shi L, Newman AH, Sibley DR. Evidence for a Stereoselective Mechanism for Bitopic Activity by Extended-Length Antagonists of the D 3 Dopamine Receptor. ACS Chem Neurosci 2020; 11:3309-3320. [PMID: 32969645 DOI: 10.1021/acschemneuro.0c00425] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.8] [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: 12/13/2022] Open
Abstract
The D3 dopamine receptor (D3R) has been suggested as a drug target for the treatment of a number of neuropsychiatric disorders, including substance use disorders (SUD). Many D3R-selective antagonists are bivalent in nature in that they engage two distinct sites on the receptor-a primary pharmacophore binds to the orthosteric site, where dopamine binds, whereas a secondary pharmacophore interacts with a unique secondary binding pocket (SBP). When engagement of the secondary pocket exerts allosteric activity, the compound is said to be bitopic. We recently reported the synthesis and characterization of two bitopic antagonists of the D3R, (±)-VK04-87 and (±)-VK05-95, which incorporated a racemic trans-cyclopropylmethyl linking chain. To gain a better understanding of the role of chirality in determining the pharmacology of such compounds, we resolved the enantiomers of (±)-VK04-87. We found that the (+)-isomer displays higher affinity for the D3R and exhibits greater selectivity versus the D2R than the (-)-isomer. Strikingly, using functional assays, we found that (+)-VK04-87 inhibits the D3R in a noncompetitive manner, while (-)-VK04-87 behaves as a purely competitive antagonist, indicating that the apparent allosteric activity of the racemate is due to the (+)-isomer. Molecular dynamic simulations of (+)-VK04-87 and (-)-VK04-87 binding to the D3R suggest that the (+)-isomer is able to interact with the SBP of the receptor whereas the (-)-isomer bends away from this pocket, thus potentially explaining their differing pharmacology. These results emphasize the importance of the linker, and its isomeric conformations, within extended-length molecules for their positioning and engagement within GPCR binding pockets.
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Affiliation(s)
- Amy E. Moritz
- Molecular Neuropharmacology Section, National Institute of Neurological Disorders and Stroke, Intramural Research Program, National Institutes of Health, 35 Convent Drive, MSC-3723, Bethesda, Maryland 20892-3723, United States
| | - Alessandro Bonifazi
- Medicinal Chemistry Section, Molecular Targets and Medication Discovery Branch, National Institute on Drug Abuse, Intramural Research Program, National Institutes of Health, 333 Cassell Drive, Baltimore, Maryland 21224, United States
| | - Adrian M. Guerrero
- Medicinal Chemistry Section, Molecular Targets and Medication Discovery Branch, National Institute on Drug Abuse, Intramural Research Program, National Institutes of Health, 333 Cassell Drive, Baltimore, Maryland 21224, United States
| | - Vivek Kumar
- Medicinal Chemistry Section, Molecular Targets and Medication Discovery Branch, National Institute on Drug Abuse, Intramural Research Program, National Institutes of Health, 333 Cassell Drive, Baltimore, Maryland 21224, United States
| | - R. Benjamin Free
- Molecular Neuropharmacology Section, National Institute of Neurological Disorders and Stroke, Intramural Research Program, National Institutes of Health, 35 Convent Drive, MSC-3723, Bethesda, Maryland 20892-3723, United States
| | - J. Robert Lane
- Centre of Membrane Protein and Receptors, Universities of Birmingham and Nottingham, Nottingham, United Kingdom
| | - Ravi Kumar Verma
- Computational Chemistry and Molecular Biophysics Unit, Molecular Targets and Medications Discovery Branch, National Institute on Drug Abuse, National Institutes of Health, 333 Cassell Drive, Baltimore, Maryland 21224, United States
| | - Lei Shi
- Computational Chemistry and Molecular Biophysics Unit, Molecular Targets and Medications Discovery Branch, National Institute on Drug Abuse, National Institutes of Health, 333 Cassell Drive, Baltimore, Maryland 21224, United States
| | - Amy Hauck Newman
- Medicinal Chemistry Section, Molecular Targets and Medication Discovery Branch, National Institute on Drug Abuse, Intramural Research Program, National Institutes of Health, 333 Cassell Drive, Baltimore, Maryland 21224, United States
| | - David R. Sibley
- Molecular Neuropharmacology Section, National Institute of Neurological Disorders and Stroke, Intramural Research Program, National Institutes of Health, 35 Convent Drive, MSC-3723, Bethesda, Maryland 20892-3723, United States
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Zhuang Y, Liu H, Edward Zhou X, Kumar Verma R, de Waal PW, Jang W, Xu TH, Wang L, Meng X, Zhao G, Kang Y, Melcher K, Fan H, Lambert NA, Eric Xu H, Zhang C. Structure of formylpeptide receptor 2-G i complex reveals insights into ligand recognition and signaling. Nat Commun 2020; 11:885. [PMID: 32060286 PMCID: PMC7021761 DOI: 10.1038/s41467-020-14728-9] [Citation(s) in RCA: 68] [Impact Index Per Article: 17.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/23/2019] [Accepted: 01/29/2020] [Indexed: 02/06/2023] Open
Abstract
Formylpeptide receptors (FPRs) as G protein-coupled receptors (GPCRs) can recognize formylpeptides derived from pathogens or host cells to function in host defense and cell clearance. In addition, FPRs, especially FPR2, can also recognize other ligands with a large chemical diversity generated at different stages of inflammation to either promote or resolve inflammation in order to maintain a balanced inflammatory response. The mechanism underlying promiscuous ligand recognition and activation of FPRs is not clear. Here we report a cryo-EM structure of FPR2-Gi signaling complex with a peptide agonist. The structure reveals a widely open extracellular region with an amphiphilic environment for ligand binding. Together with computational docking and simulation, the structure suggests a molecular basis for the recognition of formylpeptides and a potential mechanism of receptor activation, and reveals conserved and divergent features in Gi coupling. Our results provide a basis for understanding the molecular mechanism of the functional promiscuity of FPRs.
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Affiliation(s)
- Youwen Zhuang
- The CAS Key Laboratory of Receptor Research, Shanghai Institute of Materia Medica, Chinese Academy of Sciences, Shanghai, 201203, China
- University of Chinese Academy of Sciences, Beijing, 100049, China
- Center for Cancer and Cell Biology, Program for Structural Biology, Van Andel Research Institute, Grand Rapids, MI, 49503, USA
| | - Heng Liu
- Laboratory for GPCR Biology, Department of Pharmacology and Chemical Biology, University of Pittsburgh School of Medicine, University of Pittsburgh, Pittsburgh, PA, 15261, USA
| | - X Edward Zhou
- Center for Cancer and Cell Biology, Program for Structural Biology, Van Andel Research Institute, Grand Rapids, MI, 49503, USA
| | - Ravi Kumar Verma
- Bioinformatics Institute (BII), Agency for Science, Technology and Research (A*STAR), Singapore, Singapore
| | - Parker W de Waal
- Center for Cancer and Cell Biology, Program for Structural Biology, Van Andel Research Institute, Grand Rapids, MI, 49503, USA
| | - Wonjo Jang
- Department of Pharmacology and Toxicology, Medical College of Georgia, Augusta University, Augusta, GA, 30912, USA
| | - Ting-Hai Xu
- Center for Cancer and Cell Biology, Program for Structural Biology, Van Andel Research Institute, Grand Rapids, MI, 49503, USA
| | - Lei Wang
- Laboratory for GPCR Biology, Department of Pharmacology and Chemical Biology, University of Pittsburgh School of Medicine, University of Pittsburgh, Pittsburgh, PA, 15261, USA
| | - Xing Meng
- David Van Andel Advanced Cryo-Electron Microscopy Suite, Van Andel Research Institute, Grand Rapids, MI, 49503, USA
| | - Gongpu Zhao
- David Van Andel Advanced Cryo-Electron Microscopy Suite, Van Andel Research Institute, Grand Rapids, MI, 49503, USA
| | - Yanyong Kang
- Center for Cancer and Cell Biology, Program for Structural Biology, Van Andel Research Institute, Grand Rapids, MI, 49503, USA
- Takeda Research, 9625 Towne Centre Drive, San Diego, CA, 92130, USA
| | - Karsten Melcher
- Center for Cancer and Cell Biology, Program for Structural Biology, Van Andel Research Institute, Grand Rapids, MI, 49503, USA
| | - Hao Fan
- Bioinformatics Institute (BII), Agency for Science, Technology and Research (A*STAR), Singapore, Singapore
| | - Nevin A Lambert
- Department of Pharmacology and Toxicology, Medical College of Georgia, Augusta University, Augusta, GA, 30912, USA
| | - H Eric Xu
- The CAS Key Laboratory of Receptor Research, Shanghai Institute of Materia Medica, Chinese Academy of Sciences, Shanghai, 201203, China.
- Center for Cancer and Cell Biology, Program for Structural Biology, Van Andel Research Institute, Grand Rapids, MI, 49503, USA.
| | - Cheng Zhang
- Laboratory for GPCR Biology, Department of Pharmacology and Chemical Biology, University of Pittsburgh School of Medicine, University of Pittsburgh, Pittsburgh, PA, 15261, USA.
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16
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Sanchez-Soto M, Verma RK, Willette BKA, Gonye EC, Moore AM, Moritz AE, Boateng CA, Yano H, Free RB, Shi L, Sibley DR. A structural basis for how ligand binding site changes can allosterically regulate GPCR signaling and engender functional selectivity. Sci Signal 2020; 13:13/617/eaaw5885. [PMID: 32019899 DOI: 10.1126/scisignal.aaw5885] [Citation(s) in RCA: 25] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022]
Abstract
Signaling bias is the propensity for some agonists to preferentially stimulate G protein-coupled receptor (GPCR) signaling through one intracellular pathway versus another. We previously identified a G protein-biased agonist of the D2 dopamine receptor (D2R) that results in impaired β-arrestin recruitment. This signaling bias was predicted to arise from unique interactions of the ligand with a hydrophobic pocket at the interface of the second extracellular loop and fifth transmembrane segment of the D2R. Here, we showed that residue Phe189 within this pocket (position 5.38 using Ballesteros-Weinstein numbering) functions as a microswitch for regulating receptor interactions with β-arrestin. This residue is relatively conserved among class A GPCRs, and analogous mutations within other GPCRs similarly impaired β-arrestin recruitment while maintaining G protein signaling. To investigate the mechanism of this signaling bias, we used an active-state structure of the β2-adrenergic receptor (β2R) to build β2R-WT and β2R-Y1995.38A models in complex with the full β2R agonist BI-167107 for molecular dynamics simulations. These analyses identified conformational rearrangements in β2R-Y1995.38A that propagated from the extracellular ligand binding site to the intracellular surface, resulting in a modified orientation of the second intracellular loop in β2R-Y1995.38A, which is predicted to affect its interactions with β-arrestin. Our findings provide a structural basis for how ligand binding site alterations can allosterically affect GPCR-transducer interactions and result in biased signaling.
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Affiliation(s)
- Marta Sanchez-Soto
- Molecular Neuropharmacology Section, NINDS, NIH, 35 Convent Drive, Room 3A201, Bethesda, MD 20892, USA
| | - Ravi Kumar Verma
- Computational Chemistry and Molecular Biophysics Unit, NIDA, NIH, TRIAD Technology Center, 333 Cassell Drive, Room 1121, Baltimore, MD 21224, USA
| | - Blair K A Willette
- Molecular Neuropharmacology Section, NINDS, NIH, 35 Convent Drive, Room 3A201, Bethesda, MD 20892, USA
| | - Elizabeth C Gonye
- Molecular Neuropharmacology Section, NINDS, NIH, 35 Convent Drive, Room 3A201, Bethesda, MD 20892, USA
| | - Annah M Moore
- Molecular Neuropharmacology Section, NINDS, NIH, 35 Convent Drive, Room 3A201, Bethesda, MD 20892, USA
| | - Amy E Moritz
- Molecular Neuropharmacology Section, NINDS, NIH, 35 Convent Drive, Room 3A201, Bethesda, MD 20892, USA
| | - Comfort A Boateng
- Basic Pharmaceutical Sciences, High Point University, One University Parkway, High Point, NC 27268, USA
| | - Hideaki Yano
- Computational Chemistry and Molecular Biophysics Unit, NIDA, NIH, TRIAD Technology Center, 333 Cassell Drive, Room 1121, Baltimore, MD 21224, USA
| | - R Benjamin Free
- Molecular Neuropharmacology Section, NINDS, NIH, 35 Convent Drive, Room 3A201, Bethesda, MD 20892, USA
| | - Lei Shi
- Computational Chemistry and Molecular Biophysics Unit, NIDA, NIH, TRIAD Technology Center, 333 Cassell Drive, Room 1121, Baltimore, MD 21224, USA.
| | - David R Sibley
- Molecular Neuropharmacology Section, NINDS, NIH, 35 Convent Drive, Room 3A201, Bethesda, MD 20892, USA.
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Cislaghi B, Bankar S, Verma RK, Heise L, Collumbien M. Widening cracks in patriarchy: mothers and daughters navigating gender norms in a Mumbai slum. Cult Health Sex 2020; 22:166-183. [PMID: 30885069 DOI: 10.1080/13691058.2019.1580769] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/16/2023]
Abstract
Inequitable gender norms can be harmful to girls' and boys' health and sexuality. Programmatic approaches that help renegotiate gendered power relationships are sorely needed. This qualitative study reveals how Parivartan, a sport-based intervention in a Mumbai informal settlement, helped families resist inequitable gender norms that limited girls' mobility in public spaces. Fifteen girl athletes were interviewed in two rounds of face-to-face in-depth interviews. Results identify the strategies girls' mothers used to support their daughters' participation in the programme when they feared their husbands' disapproval. Rather than openly confronting their husbands, mothers worked from within the patriarchal gender order, through its 'cracks', for instance initially hiding their daughters' participation from their husbands. At an appropriate moment, girls' mothers revealed to their husbands about their daughters playing sports, convincing them of the usefulness of the programme. Girls' participation profoundly and positively affected relationships between daughters, mothers and fathers. Over time, parents' trust that girls would not compromise family honour increased, eventually changing the acceptability of girls' playing sport in public in spite of the patriarchal gender order. Concluding remarks offer key implications for effective interventions, highlighting the historical nature of gender transformation processes.
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Affiliation(s)
- Beniamino Cislaghi
- Global Health and Development, London School of Hygiene and Tropical Medicine, London, UK
| | - Shweta Bankar
- International Centre for Research on Women, New Delhi, India
| | | | - Lori Heise
- Global Health and Development, London School of Hygiene and Tropical Medicine, London, UK
- Johns Hopkins Bloomberg School of Public Health, Baltimore, MA, USA
| | - Martine Collumbien
- Global Health and Development, London School of Hygiene and Tropical Medicine, London, UK
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18
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Lane JR, Abramyan AM, Adhikari P, Keen AC, Lee KH, Sanchez J, Verma RK, Lim HD, Yano H, Javitch JA, Shi L. Distinct inactive conformations of the dopamine D2 and D3 receptors correspond to different extents of inverse agonism. eLife 2020; 9:e52189. [PMID: 31985399 PMCID: PMC7053997 DOI: 10.7554/elife.52189] [Citation(s) in RCA: 17] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/25/2019] [Accepted: 01/24/2020] [Indexed: 01/07/2023] Open
Abstract
By analyzing and simulating inactive conformations of the highly homologous dopamine D2 and D3 receptors (D2R and D3R), we find that eticlopride binds D2R in a pose very similar to that in the D3R/eticlopride structure but incompatible with the D2R/risperidone structure. In addition, risperidone occupies a sub-pocket near the Na+ binding site, whereas eticlopride does not. Based on these findings and our experimental results, we propose that the divergent receptor conformations stabilized by Na+-sensitive eticlopride and Na+-insensitive risperidone correspond to different degrees of inverse agonism. Moreover, our simulations reveal that the extracellular loops are highly dynamic, with spontaneous transitions of extracellular loop 2 from the helical conformation in the D2R/risperidone structure to an extended conformation similar to that in the D3R/eticlopride structure. Our results reveal previously unappreciated diversity and dynamics in the inactive conformations of D2R. These findings are critical for rational drug discovery, as limiting a virtual screen to a single conformation will miss relevant ligands.
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Affiliation(s)
- J Robert Lane
- Division of Pharmacology, Physiology and Neuroscience, School of Life Sciences, Queen’s Medical Centre, University of NottinghamNottinghamUnited Kingdom
- Centre of Membrane Protein and Receptors, Universities of Birmingham and NottinghamNottinghamUnited Kingdom
| | - Ara M Abramyan
- Computational Chemistry and Molecular Biophysics Unit, National Institute on Drug Abuse - Intramural Research Program, National Institutes of HealthBaltimoreUnited States
| | - Pramisha Adhikari
- Computational Chemistry and Molecular Biophysics Unit, National Institute on Drug Abuse - Intramural Research Program, National Institutes of HealthBaltimoreUnited States
| | - Alastair C Keen
- Division of Pharmacology, Physiology and Neuroscience, School of Life Sciences, Queen’s Medical Centre, University of NottinghamNottinghamUnited Kingdom
- Centre of Membrane Protein and Receptors, Universities of Birmingham and NottinghamNottinghamUnited Kingdom
- Drug Discovery Biology, Department of Pharmacology and Medicinal Chemistry, Monash Institute of Pharmaceutical Sciences, Monash UniversityParkvilleAustralia
| | - Kuo-Hao Lee
- Computational Chemistry and Molecular Biophysics Unit, National Institute on Drug Abuse - Intramural Research Program, National Institutes of HealthBaltimoreUnited States
| | - Julie Sanchez
- Division of Pharmacology, Physiology and Neuroscience, School of Life Sciences, Queen’s Medical Centre, University of NottinghamNottinghamUnited Kingdom
- Centre of Membrane Protein and Receptors, Universities of Birmingham and NottinghamNottinghamUnited Kingdom
| | - Ravi Kumar Verma
- Computational Chemistry and Molecular Biophysics Unit, National Institute on Drug Abuse - Intramural Research Program, National Institutes of HealthBaltimoreUnited States
| | - Herman D Lim
- Drug Discovery Biology, Department of Pharmacology and Medicinal Chemistry, Monash Institute of Pharmaceutical Sciences, Monash UniversityParkvilleAustralia
| | - Hideaki Yano
- Computational Chemistry and Molecular Biophysics Unit, National Institute on Drug Abuse - Intramural Research Program, National Institutes of HealthBaltimoreUnited States
| | - Jonathan A Javitch
- Department of Psychiatry, Vagelos College of Physicians and Surgeons, Columbia UniversityNew YorkUnited States
- Division of Molecular Therapeutics, New York State Psychiatric InstituteNew YorkUnited States
- Department of PharmacologyVagelos College of Physicians and Surgeons, Columbia UniversityNew YorkUnited States
| | - Lei Shi
- Computational Chemistry and Molecular Biophysics Unit, National Institute on Drug Abuse - Intramural Research Program, National Institutes of HealthBaltimoreUnited States
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Hui Leow JW, Hao Lim AB, Verma RK, Fan H, Yong Chan EC. P102 - Predicting risk of cardiac arrhythmias based on inhibitory potencies (Ki) against CYP2J2-mediated arachidonic acid metabolism. Drug Metab Pharmacokinet 2020. [DOI: 10.1016/j.dmpk.2020.04.103] [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: 11/28/2022]
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20
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Soto MS, Verma RK, Willette BK, Gonye EC, Moore AM, Chun LS, Moritz AE, Yano H, Free RB, Shi L, Sibley DR. Identification of an agonist binding site motif that regulates biased signaling of GPCRs through altered conformations of intracellular loop 2. FASEB J 2019. [DOI: 10.1096/fasebj.2019.33.1_supplement.503.4] [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] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Affiliation(s)
| | - Ravi Kumar Verma
- Computational Chemistry and Molecular Biophysics UnitNIH/NIDABaltimoreMD
| | | | | | - Annah M Moore
- Molecular Neuropharmacology SectionNIH/NINDSBethesdaMD
| | - Lani S Chun
- Molecular Neuropharmacology SectionNIH/NINDSBethesdaMD
| | - Amy E Moritz
- Molecular Neuropharmacology SectionNIH/NINDSBethesdaMD
| | - Hideaki Yano
- Computational Chemistry and Molecular Biophysics UnitNIH/NIDABaltimoreMD
| | | | - Lei Shi
- Computational Chemistry and Molecular Biophysics UnitNIH/NIDABaltimoreMD
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22
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Jain A, Verma RK, Sankararamakrishnan R. Presence of Intra-helical Salt-Bridge in Loop E Half-Helix Can Influence the Transport Properties of AQP1 and GlpF Channels: Molecular Dynamics Simulations of In Silico Mutants. J Membr Biol 2018; 252:17-29. [PMID: 30470864 DOI: 10.1007/s00232-018-0054-7] [Citation(s) in RCA: 2] [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] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/27/2018] [Accepted: 11/09/2018] [Indexed: 11/25/2022]
Abstract
Major intrinsic protein (MIP) superfamily contains water-transporting AQP1 and glycerol-specific GlpF belonging to two major phylogenetic groups, namely aquaporins (AQPs) and aquaglyceroporins (AQGPs). MIP channels have six transmembrane helices (TM1 to TM6) and two half-helices (LB and LE). LE region contributes two residues to the aromatic/arginine (Ar/R) selectivity filter (SF) within the MIP channel. Bioinformatics analyses have shown that all AQGPs have an intra-helical salt-bridge (IHSB) in LE half-helix and all AQGPs and majority of AQPs have helix destabilizing Gly and/or Pro in the same region. In this paper, we mutated in silico the acidic and basic residues in GlpF to Ser and introduced salt-bridge interaction in AQP1 LE half-helix by substituting Ser residues at the equivalent positions with acidic and basic residues. We investigated the influence of IHSB in LE half-helix on the transport properties of GlpF and AQP1 mutant channels using molecular dynamics simulations. With IHSB abolished in LE half-helix, the GlpF mutant exhibited a significantly reduced water transport. In contrast, the introduction of IHSB in the two AQP1 mutants has increased water transport. Absence of salt-bridge in LE half-helix alters the SF geometry and results in a higher energy barrier for the solutes in the Ar/R selectivity filter. Presence/absence of IHSB in LE half-helix influences the channel transport properties and it is evident especially for the AQGPs. By modulating its helical flexibility, LE half-helix can perhaps play a regulatory role in transport either on its own or in conjunction with other extracellular regions.
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Affiliation(s)
- Alok Jain
- Department of Biological Sciences and Bioengineering, Indian Institute of Technology Kanpur, Kanpur, 208016, India
- National Institute of Pharmaceutical Education and Research, Ahmedabad, India
| | - Ravi Kumar Verma
- Department of Biological Sciences and Bioengineering, Indian Institute of Technology Kanpur, Kanpur, 208016, India
- Bioinformatics Institute, 30 Biopolis Street, #07-01 Matrix, Singapore, 138671, Singapore
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Soto MS, Willette BKA, Gonye EC, Moore AM, Chun LS, Moritz AE, Verma RK, Yano H, Shi L, Free RB, Sibley DR. Identification of Residues in the Fifth Transmembrane‐Spanning Domain of the D2‐like Dopamine Receptors that Engender Signaling Bias. FASEB J 2018. [DOI: 10.1096/fasebj.2018.32.1_supplement.827.11] [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] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Affiliation(s)
| | | | | | | | - Lani S. Chun
- Molecular Neuropharmacology SectionNINDS, NIHBethesdaMD
| | - Amy E. Moritz
- Molecular Neuropharmacology SectionNINDS, NIHBethesdaMD
| | - Ravi Kumar Verma
- Computational Chemistry and Molecular Biophysics UnitNIDA, NIHBaltimoreMD
| | - Hideaki Yano
- Computational Chemistry and Molecular Biophysics UnitNIDA, NIHBaltimoreMD
| | - Lei Shi
- Computational Chemistry and Molecular Biophysics UnitNIDA, NIHBaltimoreMD
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Chayanika K, Krishna V, Sanjay K, Verma RK, Verma CM, Pandey U. Transient Stress Lymphocytosis in Cardiac Emergencies: A Clinicopathological Study of Under-recognized Entity at a Tertiary Care Cardiology Institute in North India. J Cardiovasc Dis Res 2018. [DOI: 10.5530/jcdr.2018.1.9] [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: 11/23/2022] Open
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Moritz AE, Guerrero A, Kumar V, Bonifazi A, Free RB, Lane JR, Verma RK, Shi L, Newman AH, Sibley DR. Evidence for a Stereoselective Mechanism of Action for Non‐competitive Antagonism of the D3 Dopamine Receptor by Extended‐Length Bitopic Ligands. FASEB J 2018. [DOI: 10.1096/fasebj.2018.32.1_supplement.827.12] [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] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Affiliation(s)
- Amy E. Moritz
- Molecular Neuropharmacology SectionNINDS, NIHBethesdaMD
| | | | - Vivek Kumar
- Medicinal Chemistry SectionNIDA, NIHBaltimoreMD
| | | | | | | | - Ravi Kumar Verma
- Computational Chemistry and Molecular Biophysics UnitNIDA, NIHBaltimoreMD
| | - Lei Shi
- Computational Chemistry and Molecular Biophysics UnitNIDA, NIHBaltimoreMD
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Draper-Joyce CJ, Verma RK, Michino M, Shonberg J, Kopinathan A, Klein Herenbrink C, Scammells PJ, Capuano B, Abramyan AM, Thal DM, Javitch JA, Christopoulos A, Shi L, Lane JR. The action of a negative allosteric modulator at the dopamine D 2 receptor is dependent upon sodium ions. Sci Rep 2018; 8:1208. [PMID: 29352161 PMCID: PMC5775417 DOI: 10.1038/s41598-018-19642-1] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.3] [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: 11/08/2017] [Accepted: 12/19/2017] [Indexed: 01/11/2023] Open
Abstract
Sodium ions (Na+) allosterically modulate the binding of orthosteric agonists and antagonists to many class A G protein-coupled receptors, including the dopamine D2 receptor (D2R). Experimental and computational evidences have revealed that this effect is mediated by the binding of Na+ to a conserved site located beneath the orthosteric binding site (OBS). SB269652 acts as a negative allosteric modulator (NAM) of the D2R that adopts an extended bitopic pose, in which the tetrahydroisoquinoline moiety interacts with the OBS and the indole-2-carboxamide moiety occupies a secondary binding pocket (SBP). In this study, we find that the presence of a Na+ within the conserved Na+-binding pocket is required for the action of SB269652. Using fragments of SB269652 and novel full-length analogues, we show that Na+ is required for the high affinity binding of the tetrahydroisoquinoline moiety within the OBS, and that the interaction of the indole-2-carboxamide moiety with the SBP determines the degree of Na+-sensitivity. Thus, we extend our understanding of the mode of action of this novel class of NAM by showing it acts synergistically with Na+ to modulate the binding of orthosteric ligands at the D2R, providing opportunities for fine-tuning of modulatory effects in future allosteric drug design efforts.
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Affiliation(s)
- Christopher J Draper-Joyce
- Drug Discovery Biology, Monash Institute of Pharmaceutical Sciences, Monash University, 399 Royal Parade, Parkville, VIC 3052, Australia
| | - Ravi Kumar Verma
- Computational Chemistry and Molecular Biophysics Unit, National Institute on Drug Abuse Intramural Research Program, National Institutes of Health, 333 Cassell Drive, Baltimore, Maryland, 21224, United States
| | - Mayako Michino
- Computational Chemistry and Molecular Biophysics Unit, National Institute on Drug Abuse Intramural Research Program, National Institutes of Health, 333 Cassell Drive, Baltimore, Maryland, 21224, United States.,Tri-Institutional Therapeutics Discovery Institute, 413 E 69th St, New York, NY, 10021, United States
| | - Jeremy Shonberg
- Medicinal Chemistry, Monash Institute of Pharmaceutical Sciences, Monash University, 399 Royal Parade, Parkville, VIC 3052, Australia
| | - Anitha Kopinathan
- Medicinal Chemistry, Monash Institute of Pharmaceutical Sciences, Monash University, 399 Royal Parade, Parkville, VIC 3052, Australia
| | - Carmen Klein Herenbrink
- Drug Discovery Biology, Monash Institute of Pharmaceutical Sciences, Monash University, 399 Royal Parade, Parkville, VIC 3052, Australia
| | - Peter J Scammells
- Medicinal Chemistry, Monash Institute of Pharmaceutical Sciences, Monash University, 399 Royal Parade, Parkville, VIC 3052, Australia
| | - Ben Capuano
- Medicinal Chemistry, Monash Institute of Pharmaceutical Sciences, Monash University, 399 Royal Parade, Parkville, VIC 3052, Australia
| | - Ara M Abramyan
- Computational Chemistry and Molecular Biophysics Unit, National Institute on Drug Abuse Intramural Research Program, National Institutes of Health, 333 Cassell Drive, Baltimore, Maryland, 21224, United States
| | - David M Thal
- Drug Discovery Biology, Monash Institute of Pharmaceutical Sciences, Monash University, 399 Royal Parade, Parkville, VIC 3052, Australia
| | - Jonathan A Javitch
- Departments of Psychiatry and Pharmacology, New York State Psychiatric Institute, New York, New York, 10032, United States.,College of Physicians and Surgeons, Columbia University, and Division of Molecular Therapeutics, New York State Psychiatric Institute, New York, New York, 10032, United States
| | - Arthur Christopoulos
- Drug Discovery Biology, Monash Institute of Pharmaceutical Sciences, Monash University, 399 Royal Parade, Parkville, VIC 3052, Australia
| | - Lei Shi
- Computational Chemistry and Molecular Biophysics Unit, National Institute on Drug Abuse Intramural Research Program, National Institutes of Health, 333 Cassell Drive, Baltimore, Maryland, 21224, United States.
| | - J Robert Lane
- Drug Discovery Biology, Monash Institute of Pharmaceutical Sciences, Monash University, 399 Royal Parade, Parkville, VIC 3052, Australia.
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Verma RK, Abramyan AM, Michino M, Free RB, Sibley DR, Javitch JA, Lane JR, Shi L. The E2.65A mutation disrupts dynamic binding poses of SB269652 at the dopamine D2 and D3 receptors. PLoS Comput Biol 2018; 14:e1005948. [PMID: 29337986 PMCID: PMC5786319 DOI: 10.1371/journal.pcbi.1005948] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/30/2017] [Revised: 01/26/2018] [Accepted: 12/30/2017] [Indexed: 12/15/2022] Open
Abstract
The dopamine D2 and D3 receptors (D2R and D3R) are important targets for antipsychotics and for the treatment of drug abuse. SB269652, a bitopic ligand that simultaneously binds both the orthosteric binding site (OBS) and a secondary binding pocket (SBP) in both D2R and D3R, was found to be a negative allosteric modulator. Previous studies identified Glu2.65 in the SBP to be a key determinant of both the affinity of SB269652 and the magnitude of its cooperativity with orthosteric ligands, as the E2.65A mutation decreased both of these parameters. However, the proposed hydrogen bond (H-bond) between Glu2.65 and the indole moiety of SB269652 is not a strong interaction, and a structure activity relationship study of SB269652 indicates that this H-bond may not be the only element that determines its allosteric properties. To understand the structural basis of the observed phenotype of E2.65A, we carried out molecular dynamics simulations with a cumulative length of ~77 μs of D2R and D3R wild-type and their E2.65A mutants bound to SB269652. In combination with Markov state model analysis and by characterizing the equilibria of ligand binding modes in different conditions, we found that in both D2R and D3R, whereas the tetrahydroisoquinoline moiety of SB269652 is stably bound in the OBS, the indole-2-carboxamide moiety is dynamic and only intermittently forms H-bonds with Glu2.65. Our results also indicate that the E2.65A mutation significantly affects the overall shape and size of the SBP, as well as the conformation of the N terminus. Thus, our findings suggest that the key role of Glu2.65 in mediating the allosteric properties of SB269652 extends beyond a direct interaction with SB269652, and provide structural insights for rational design of SB269652 derivatives that may retain its allosteric properties. G protein-coupled receptors (GPCRs) are targets of more than 25% of prescription drugs on the market. Due to their critical roles in human physiology, competitive modulation of these receptors has been found to be associated with many undesired side effects. Allosteric modulation holds the promise of retaining normal receptor function and improving selectivity. However, the underlying molecular mechanisms of the allosteric modulation of GPCRs have remained largely uncharted. The dopamine D2-like receptors have been implicated in voluntary movement, reward, sleep, learning, and memory. Based on previous experimental findings, we computationally characterized the binding of a negative allosteric modulator of dopamine D2 and D3 receptors, and revealed the dynamic binding mode of this modulator in a secondary binding pocket (SBP) of the receptors. Our results highlight the key role of a Glu in mediating the allosteric properties of the modulator by shaping the dynamically formed SBP, and shed light on rational design and optimization of allosteric modulators of GPCRs.
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Affiliation(s)
- Ravi Kumar Verma
- Computational Chemistry and Molecular Biophysics Unit, Molecular Targets and Medications Discovery Branch, National Institute on Drug Abuse—Intramural Research Program, National Institutes of Health, Baltimore, Maryland, United States
| | - Ara M. Abramyan
- Computational Chemistry and Molecular Biophysics Unit, Molecular Targets and Medications Discovery Branch, National Institute on Drug Abuse—Intramural Research Program, National Institutes of Health, Baltimore, Maryland, United States
| | - Mayako Michino
- Computational Chemistry and Molecular Biophysics Unit, Molecular Targets and Medications Discovery Branch, National Institute on Drug Abuse—Intramural Research Program, National Institutes of Health, Baltimore, Maryland, United States
| | - R. Benjamin Free
- Molecular Neuropharmacology Section, National Institute of Neurologic Disorders and Stroke, National Institutes of Health, Bethesda, Maryland, United States
| | - David R. Sibley
- Molecular Neuropharmacology Section, National Institute of Neurologic Disorders and Stroke, National Institutes of Health, Bethesda, Maryland, United States
| | - Jonathan A. Javitch
- Departments of Psychiatry and Pharmacology, College of Physicians and Surgeons, Columbia University, New York, New York, United States
- Division of Molecular Therapeutics, New York State Psychiatric Institute, New York, New York, United States
| | - J. Robert Lane
- Drug Discovery Biology, Department of Pharmacology and Medicinal Chemistry, Monash Institute of Pharmaceutical Sciences, Monash University (Parkville campus), Parkville, Victoria, Australia
| | - Lei Shi
- Computational Chemistry and Molecular Biophysics Unit, Molecular Targets and Medications Discovery Branch, National Institute on Drug Abuse—Intramural Research Program, National Institutes of Health, Baltimore, Maryland, United States
- * E-mail:
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Draper-Joyce CJ, Michino M, Verma RK, Klein Herenbrink C, Shonberg J, Kopinathan A, Scammells PJ, Capuano B, Thal DM, Javitch JA, Christopoulos A, Shi L, Lane JR. The structural determinants of the bitopic binding mode of a negative allosteric modulator of the dopamine D 2 receptor. Biochem Pharmacol 2018; 148:315-328. [PMID: 29325769 DOI: 10.1016/j.bcp.2018.01.002] [Citation(s) in RCA: 22] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/31/2017] [Accepted: 01/02/2018] [Indexed: 01/11/2023]
Abstract
SB269652 is a negative allosteric modulator of the dopamine D2 receptor (D2R) yet possesses structural similarity to ligands with a competitive mode of interaction. In this study, we aimed to understand the ligand-receptor interactions that confer its allosteric action. We combined site-directed mutagenesis with molecular dynamics simulations using both SB269652 and derivatives from our previous structure activity studies. We identify residues within the conserved orthosteric binding site (OBS) and a secondary binding pocket (SBP) that determine affinity and cooperativity. Our results indicate that interaction with the SBP is a requirement for allosteric pharmacology, but that both competitive and allosteric derivatives of SB269652 can display sensitivity to the mutation of a glutamate residue (E952.65) within the SBP. Our findings provide the molecular basis for the differences in affinity between SB269652 derivatives, and reveal how changes to interactions made by the primary pharmacophore of SB269652 in the orthosteric pocket can confer changes in the interactions made by the secondary pharmacophore in the SBP. Our insights provide a structure-activity framework towards rational optimization of bitopic ligands for D2R with tailored competitive versus allosteric properties.
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Affiliation(s)
- Christopher J Draper-Joyce
- Drug Discovery Biology, Monash Institute of Pharmaceutical Sciences, Monash University (Parkville campus), 399 Royal Parade, Parkville, VIC 3052, Australia
| | - Mayako Michino
- Computational Chemistry and Molecular Biophysics Unit, National Institute on Drug Abuse Intramural Research Program, National Institutes of Health, 333 Cassell Drive, Baltimore, MD 21224, United States
| | - Ravi Kumar Verma
- Computational Chemistry and Molecular Biophysics Unit, National Institute on Drug Abuse Intramural Research Program, National Institutes of Health, 333 Cassell Drive, Baltimore, MD 21224, United States
| | - Carmen Klein Herenbrink
- Drug Discovery Biology, Monash Institute of Pharmaceutical Sciences, Monash University (Parkville campus), 399 Royal Parade, Parkville, VIC 3052, Australia
| | - Jeremy Shonberg
- Medicinal Chemistry, Monash Institute of Pharmaceutical Sciences, Monash University (Parkville campus), 399 Royal Parade, Parkville, VIC 3052, Australia
| | - Anitha Kopinathan
- Medicinal Chemistry, Monash Institute of Pharmaceutical Sciences, Monash University (Parkville campus), 399 Royal Parade, Parkville, VIC 3052, Australia
| | - Peter J Scammells
- Medicinal Chemistry, Monash Institute of Pharmaceutical Sciences, Monash University (Parkville campus), 399 Royal Parade, Parkville, VIC 3052, Australia
| | - Ben Capuano
- Medicinal Chemistry, Monash Institute of Pharmaceutical Sciences, Monash University (Parkville campus), 399 Royal Parade, Parkville, VIC 3052, Australia
| | - David M Thal
- Drug Discovery Biology, Monash Institute of Pharmaceutical Sciences, Monash University (Parkville campus), 399 Royal Parade, Parkville, VIC 3052, Australia
| | - Jonathan A Javitch
- Department of Psychiatry, College of Physicians and Surgeons, Columbia University, New York State Psychiatric Institute, New York, NY 10032, United States; Department of Pharmacology, College of Physicians and Surgeons, Columbia University, New York State Psychiatric Institute, New York, NY 10032, United States; Division of Molecular Therapeutics, New York State Psychiatric Institute, New York, NY 10032, United States
| | - Arthur Christopoulos
- Drug Discovery Biology, Monash Institute of Pharmaceutical Sciences, Monash University (Parkville campus), 399 Royal Parade, Parkville, VIC 3052, Australia
| | - Lei Shi
- Computational Chemistry and Molecular Biophysics Unit, National Institute on Drug Abuse Intramural Research Program, National Institutes of Health, 333 Cassell Drive, Baltimore, MD 21224, United States.
| | - J Robert Lane
- Drug Discovery Biology, Monash Institute of Pharmaceutical Sciences, Monash University (Parkville campus), 399 Royal Parade, Parkville, VIC 3052, Australia.
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Singha D, Rana S, Kumar S, Singh Y, Singh J, Verma RK. Efficacy of magnesium sulphate and/or fentanyl as adjuvants to intrathecal low-dose bupivacaine in parturients undergoing elective caesarean section. J Obstet Anaesth Crit Care 2017. [DOI: 10.4103/joacc.joacc_24_16] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/04/2022] Open
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Mann VS, Subramanyam M, Verma RK, Jha AA, John JR. Estimation and Comparison of Erythrocyte and Hemoglobin Levels in Subjects with Healthy Periodontium and Chronic Periodontitis. Pesqui bras odontopediatria clín integr 2017. [DOI: 10.4034/pboci.2017.171.41] [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: 11/15/2022] Open
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Lee YL, Verma RK, Yadav H, Barua A. Health impacts of Facebook usage and mobile texting among undergraduate dental students: it's time to understand the difference between usage and an excessive use. Eur J Dent Educ 2016; 20:218-228. [PMID: 26277860 DOI: 10.1111/eje.12164] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Accepted: 07/13/2015] [Indexed: 06/04/2023]
Abstract
BACKGROUND Facebook and mobile texting are prevalent in the lives of almost every student. However, little is known about the relationship between Facebook usage or mobile texting and their impacts on health amongst undergraduate dental students. In this study, excessive Facebook use and excessive mobile texting were studied as they relate to impacts on health. MATERIALS AND METHODS A cross-sectional study was conducted at a private university in Malaysia. A total of 188 undergraduate dental students were interviewed using a pre-tested and self-rated questionnaire. Data collected from participants were analysed using SPSS version 18.0. Chi-square test, Fisher's exact test and multiple logistic regression analyses were applied to study the relationship between explanatory variables and excessive Facebook use and excessive mobile texting. RESULTS The prevalence of excessive Facebook use and excessive mobile texting amongst undergraduate dental students was found to be 33.2% and 33.0%, respectively. According to a multivariate analysis, texting habits, such as the presence of daytime sleepiness after texting late at night (aOR = 2.682, 95% CI = 1.142-6.301) and the presence of anxious feelings if students failed to receive a timely response (aOR = 3.819, 95% CI = 1.580-9.230), were determined to be significant predictors of excessive mobile texting. Excessive Facebook use was found to be significantly related to three variables as follows: fewer numbers of close friends (aOR = 2.275, 95% CI = 1.057-4.898), the checking of updates on the Facebook walls of their friends (aOR = 2.582, 95% CI = 1.189-5.605) and the absence of active and vigorous feelings during Facebook use (aOR = 3.401, 95% CI = 1.233-9.434). CONCLUSIONS Approximately one-third of undergraduate dental students in this study experienced excessive Facebook use and/or excessive mobile texting. Health education and promotion should be instituted to create awareness, whilst students should be advised to practise self-control with respect to both mobile texting and Facebook usage.
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Affiliation(s)
- Y L Lee
- Department of Pharmacy Practice, School of Pharmacy, International Medical University, Kuala Lumpur, Malaysia
| | - R K Verma
- Department of Pharmacy Practice, School of Pharmacy, International Medical University, Kuala Lumpur, Malaysia.
| | - H Yadav
- Department of Community Medicine, School of Medicine, International Medical University, Kuala Lumpur, Malaysia
| | - A Barua
- Department of Community Medicine, School of Medicine, International Medical University, Kuala Lumpur, Malaysia
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Singh AK, Singh Y, Jain G, Verma RK. Comparison of two different doses of intrathecal dexmedetomidine as adjuvant with isobaric ropivacaine in lower abdominal surgery. Anesth Essays Res 2015; 9:343-7. [PMID: 26712971 PMCID: PMC4683479 DOI: 10.4103/0259-1162.158009] [Citation(s) in RCA: 5] [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] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/05/2022] Open
Abstract
Background: To augment the subarachnoid block utility, the efficacy of newer molecules as an adjuvant is investigated constantly. Considering the favorable profile of dexmedetomidine, it could have a potential role as an adjuvant to ropivacaine. Aim: We evaluated the efficacy of two different doses of dexmedetomidine as an adjuvant to isobaric ropivacaine, intrathecally. Methods: Ninety patients scheduled for lower abdominal surgery under spinal anesthesia were randomized into three groups to receive 2.5 ml of isobaric ropivacaine (0.75%, 7.5 mg/ml) added to 5 µg (10 µg/ml) or 10 µg (20 µg/ml) of dexmedetomidine or 0.5 ml of normal saline in group A, B or C, respectively. Block characteristics were compared as a primary outcome. Statistical Analysis: One-way analysis of variance test, Fisher's exact test/Chi-square test, whichever appropriate. A P < 0.05 was considered significant. Results: Time to achieve desired block was least in group B and maximum in group C. The sensory-motor blockade remained significantly prolonged in group B compared to other groups. Hemodynamic parameters remained stable in all three groups. Conclusion: Among the investigated doses, dexmedetomidine augments the efficacy of intrathecal ropivacaine in a dose-dependent manner, without any untoward side effects.
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Affiliation(s)
- Atul Kumar Singh
- Department of Anaesthesiology and Intensive Care, Institute of Medical Sciences, Banaras Hindu University, Varanasi, Uttar Pradesh, India
| | - Yashpal Singh
- Department of Anaesthesiology and Intensive Care, Institute of Medical Sciences, Banaras Hindu University, Varanasi, Uttar Pradesh, India
| | - Gaurav Jain
- Department of Anaesthesiology and Intensive Care, Institute of Medical Sciences, Banaras Hindu University, Varanasi, Uttar Pradesh, India
| | - Ravi Kumar Verma
- Department of Anaesthesiology and Intensive Care, Institute of Medical Sciences, Banaras Hindu University, Varanasi, Uttar Pradesh, India
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Weisstanner C, Mantokoudis G, Huth M, Verma RK, Nauer C, Senn P, Caversaccio MD, Wagner F. Radiation dose reduction in postoperative computed position control of cochlear implant electrodes in lambs - An experimental study. Int J Pediatr Otorhinolaryngol 2015; 79:2348-54. [PMID: 26596357 DOI: 10.1016/j.ijporl.2015.10.040] [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] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/14/2015] [Revised: 10/27/2015] [Accepted: 10/29/2015] [Indexed: 01/21/2023]
Abstract
OBJECTIVE Cochlear implants (CI) are standard treatment for prelingually deafened children and postlingually deafened adults. Computed tomography (CT) is the standard method for postoperative imaging of the electrode position. CT scans accurately reflect electrode depth and position, which is essential prior to use. However, routine CT examinations expose patients to radiation, which is especially problematic in children. We examined whether new CT protocols could reduce radiation doses while preserving diagnostic accuracy. METHODS To investigate whether electrode position can be assessed by low-dose CT protocols, a cadaveric lamb model was used because the inner ear morphology is similar to humans. The scans were performed at various volumetric CT dose-indexes CTDIvol)/kV combinations. For each constant CTDIvol the tube voltage was varied (i.e., 80, 100, 120 and 140kV). This procedure was repeated at different CTDIvol values (21mGy, 11mGy, 5.5mGy, 2.8mGy and 1.8mGy). To keep the CTDIvol constant at different tube voltages, the tube current values were adjusted. Independent evaluations of the images were performed by two experienced and blinded neuroradiologists. The criteria diagnostic usefulness, image quality and artifacts (scaled 1-4) were assessed in 14 cochlear-implanted cadaveric lamb heads with variable tube voltages. RESULTS Results showed that the standard CT dose could be substantially reduced without sacrificing diagnostic accuracy of electrode position. The assessment of the CI electrode position was feasible in almost all cases up to a CTDIvol of 2-3mGy. The number of artifacts did not increase for images within this dose range as compared to higher dosages. The extent of the artifacts caused by the implanted metal-containing CI electrode does not depend on the radiation dose and is not perceptibly influenced by changes in the tube voltage. Summarizing the evaluation of the CI electrode position is possible even at a very low radiation dose. CONCLUSIONS CT imaging of the temporal bone for postoperative electrode position control of the CI is possible with a very low and significantly radiation dose. The tube current-time product and voltage can be reduced by 50% without increasing artifacts. Low-dose postoperative CT scans are sufficient for localizing the CI electrode.
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Affiliation(s)
- C Weisstanner
- University Institute for Diagnostic and Interventional Neuroradiology, Inselspital, Bern, Switzerland
| | - G Mantokoudis
- University Department of Otorhinolaryngology, Head & Neck Surgery, Inselspital, Bern, Switzerland
| | - M Huth
- University Department of Otorhinolaryngology, Head & Neck Surgery, Inselspital, Bern, Switzerland
| | - R K Verma
- University Institute for Diagnostic and Interventional Neuroradiology, Inselspital, Bern, Switzerland
| | - C Nauer
- Department of Radiologie, Kantonsspital, Chur, Switzerland
| | - P Senn
- University Department of Otorhinolaryngology, Head & Neck Surgery, Inselspital, Bern, Switzerland
| | - M D Caversaccio
- University Department of Otorhinolaryngology, Head & Neck Surgery, Inselspital, Bern, Switzerland
| | - F Wagner
- University Institute for Diagnostic and Interventional Neuroradiology, Inselspital, Bern, Switzerland.
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Yadav RS, Verma RK, Bahadur A, Rai SB. Infrared to infrared upconversion emission in Pr(3+)/Yb(3+) co-doped La2O3 and La(OH)3 nano-phosphors: a comparative study. Spectrochim Acta A Mol Biomol Spectrosc 2015; 142:324-330. [PMID: 25706603 DOI: 10.1016/j.saa.2015.01.095] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/19/2014] [Revised: 01/17/2015] [Accepted: 01/29/2015] [Indexed: 06/04/2023]
Abstract
The Pr(3+)/Yb(3+) co-doped La2O3 and La(OH)3 nano-phosphors have been synthesized through solution combustion method. The structure and morphology of the samples have been studied using X-ray diffraction (XRD) and transmission electron microscopy (TEM). The physical and optical properties of the samples have been measured and compared. A broad intense infrared emission centered at 850nm due to (1)I6→(1)G4 transition along with sharp green emission centerd at 513nm due to (3)P0→(3)H4 transition are observed on excitation with 976nm laser. The emission intensity of Pr(3+) is optimized with concentration and it is maximum at 0.08mol%. The annealed samples are found to be more crystalline and emit larger photoluminescence due to removal of quenching centers. The power dependent study of green upconversion emission indicates the involvement of two photons. The phosphor in La(OH)3 phase is more stable though the photoluminescence emission is slightly weak. La(OH)3 is less toxic compared to La2O3 and is biocompatible. It generates more heat and can be used in biothermal treatment.
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Affiliation(s)
- R S Yadav
- Laser & Spectroscopy Laboratory, Department of Physics, Banaras Hindu University, Varanasi 221 005, India
| | - R K Verma
- Laser & Spectroscopy Laboratory, Department of Physics, Banaras Hindu University, Varanasi 221 005, India
| | - A Bahadur
- Laser & Spectroscopy Laboratory, Department of Physics, Banaras Hindu University, Varanasi 221 005, India
| | - S B Rai
- Laser & Spectroscopy Laboratory, Department of Physics, Banaras Hindu University, Varanasi 221 005, India.
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Verma RK, Prabh ND, Sankararamakrishnan R. Intra-helical salt-bridge and helix destabilizing residues within the same helical turn: Role of functionally important loop E half-helix in channel regulation of major intrinsic proteins. Biochim Biophys Acta 2015; 1848:1436-49. [PMID: 25797519 DOI: 10.1016/j.bbamem.2015.03.013] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/27/2014] [Revised: 03/08/2015] [Accepted: 03/13/2015] [Indexed: 12/26/2022]
Abstract
The superfamily of major intrinsic proteins (MIPs) includes aquaporin (AQP) and aquaglyceroporin (AQGP) and it is involved in the transport of water and neutral solutes across the membrane. Diverse MIP sequences adopt a unique hour-glass fold with six transmembrane helices (TM1 to TM6) and two half-helices (LB and LE). Loop E contains one of the two conserved NPA motifs and contributes two residues to the aromatic/arginine selectivity filter. Function and regulation of majority of MIP channels are not yet characterized. We have analyzed the loop E region of 1468 MIP sequences and their structural models from six different organism groups. They can be phylogenetically clustered into AQGPs, AQPs, plant MIPs and other MIPs. The LE half-helix in all AQGPs contains an intra-helical salt-bridge and helix-breaking residues Gly/Pro within the same helical turn. All non-AQGPs lack this salt-bridge but have the helix destabilizing Gly and/or Pro in the same positions. However, the segment connecting LE half-helix and TM6 is longer by 10-15 residues in AQGPs compared to all non-AQGPs. We speculate that this longer loop in AQGPs and the LE half-helix of non-AQGPs will be relatively more flexible and this could be functionally important. Molecular dynamics simulations on glycerol-specific GlpF, water-transporting AQP1, its mutant and a fungal AQP channel confirm these predictions. Thus two distinct regions of loop E, one in AQGPs and the other in non-AQGPs, seem to be capable of modulating the transport. These regions can also act in conjunction with other extracellular residues/segments to regulate MIP channel transport.
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Affiliation(s)
- Ravi Kumar Verma
- Department of Biological Sciences and Bioengineering, Indian Institute of Technology Kanpur, Kanpur 208016, India
| | - Neel Duti Prabh
- Department of Biological Sciences and Bioengineering, Indian Institute of Technology Kanpur, Kanpur 208016, India
| | - Ramasubbu Sankararamakrishnan
- Department of Biological Sciences and Bioengineering, Indian Institute of Technology Kanpur, Kanpur 208016, India; Centre of Excellence for Chemical Biology, Indian Institute of Technology Kanpur, Kanpur 208016, India.
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Gratz PP, Schroth G, Gralla J, Mattle HP, Fischer U, Jung S, Mordasini P, Hsieh K, Verma RK, Weisstanner C, El-Koussy M. Whole-Brain Susceptibility-Weighted Thrombus Imaging in Stroke: Fragmented Thrombi Predict Worse Outcome. AJNR Am J Neuroradiol 2015; 36:1277-82. [PMID: 25792535 DOI: 10.3174/ajnr.a4275] [Citation(s) in RCA: 50] [Impact Index Per Article: 5.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/24/2014] [Accepted: 12/11/2014] [Indexed: 01/14/2023]
Abstract
BACKGROUND AND PURPOSE The prevalence and clinical importance of primarily fragmented thrombi in patients with acute ischemic stroke remains elusive. Whole-brain SWI was used to detect multiple thrombus fragments, and their clinical significance was analyzed. MATERIALS AND METHODS Pretreatment SWI was analyzed for the presence of a single intracranial thrombus or multiple intracranial thrombi. Associations with baseline clinical characteristics, complications, and clinical outcome were studied. RESULTS Single intracranial thrombi were detected in 300 (92.6%), and multiple thrombi, in 24 of 324 patients (7.4%). In 23 patients with multiple thrombi, all thrombus fragments were located in the vascular territory distal to the primary occluding thrombus; in 1 patient, thrombi were found both in the anterior and posterior circulation. Only a minority of thrombus fragments were detected on TOF-MRA, first-pass gadolinium-enhanced MRA, or DSA. Patients with multiple intracranial thrombi presented with more severe symptoms (median NIHSS scores, 15 versus 11; P = .014) and larger ischemic areas (median DWI ASPECTS, 5 versus 7; P = .006); good collaterals, rated on DSA, were fewer than those in patients with a single thrombus (21.1% versus 44.2%, P = .051). The presence of multiple thrombi was a predictor of unfavorable outcome at 3 months (P = .040; OR, 0.251; 95% CI, 0.067-0.939). CONCLUSIONS Patients with multiple intracranial thrombus fragments constitute a small subgroup of patients with stroke with a worse outcome than patients with single thrombi.
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Affiliation(s)
- P P Gratz
- From the Departments of Diagnostic and Interventional Neuroradiology (P.P.G., G.S., J.G., S.J., P.M., K.H., R.K.V., C.W., M.E.-K.)
| | - G Schroth
- From the Departments of Diagnostic and Interventional Neuroradiology (P.P.G., G.S., J.G., S.J., P.M., K.H., R.K.V., C.W., M.E.-K.)
| | - J Gralla
- From the Departments of Diagnostic and Interventional Neuroradiology (P.P.G., G.S., J.G., S.J., P.M., K.H., R.K.V., C.W., M.E.-K.)
| | - H P Mattle
- Neurology (H.P.M., U.F., S.J.), Inselspital, Bern University Hospital and University of Bern, Bern, Switzerland
| | - U Fischer
- Neurology (H.P.M., U.F., S.J.), Inselspital, Bern University Hospital and University of Bern, Bern, Switzerland
| | - S Jung
- From the Departments of Diagnostic and Interventional Neuroradiology (P.P.G., G.S., J.G., S.J., P.M., K.H., R.K.V., C.W., M.E.-K.) Neurology (H.P.M., U.F., S.J.), Inselspital, Bern University Hospital and University of Bern, Bern, Switzerland
| | - P Mordasini
- From the Departments of Diagnostic and Interventional Neuroradiology (P.P.G., G.S., J.G., S.J., P.M., K.H., R.K.V., C.W., M.E.-K.)
| | - K Hsieh
- From the Departments of Diagnostic and Interventional Neuroradiology (P.P.G., G.S., J.G., S.J., P.M., K.H., R.K.V., C.W., M.E.-K.)
| | - R K Verma
- From the Departments of Diagnostic and Interventional Neuroradiology (P.P.G., G.S., J.G., S.J., P.M., K.H., R.K.V., C.W., M.E.-K.)
| | - C Weisstanner
- From the Departments of Diagnostic and Interventional Neuroradiology (P.P.G., G.S., J.G., S.J., P.M., K.H., R.K.V., C.W., M.E.-K.)
| | - M El-Koussy
- From the Departments of Diagnostic and Interventional Neuroradiology (P.P.G., G.S., J.G., S.J., P.M., K.H., R.K.V., C.W., M.E.-K.)
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Yadav RS, Verma RK, Bahadur A, Rai SB. Structural characterizations and intense green upconversion emission in Yb3+, Pr3+ co-doped Y2O3 nano-phosphor. Spectrochim Acta A Mol Biomol Spectrosc 2015; 137:357-362. [PMID: 25233026 DOI: 10.1016/j.saa.2014.08.078] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/16/2014] [Revised: 08/20/2014] [Accepted: 08/24/2014] [Indexed: 06/03/2023]
Abstract
We report the structural and optical properties of Yb(3+), Pr(3+) co-doped Y2O3 nano-phosphor synthesized through solution combustion method. The structural studies reveal the nano-crystalline structure of the sample. The energy dispersive spectroscopy (EDS) measurements confirm the presence of Y, O, Pr and Yb elements in the sample. Fourier transform infrared studies show the vibrational features of the samples. The fluorescence spectra of the samples have been monitored on excitation with 976 nm and the intense green upconversion emission observed at 552 nm is due to (3)P0→(3)H5 electronic transition. The concentration of Pr(3+) ion in the sample is optimized and the fluorescence intensity is maximum at 0.08 mol% of Pr(3+). The power dependence studies reveal the involvement of two photons in the emission process. The possible mechanism of upconversion has been discussed on the basis of schematic energy level diagram. The sample annealed at higher temperature enhances the fluorescence intensity up to 8 times and this enhancement is discussed in terms of the removal of optical quenching centers. The nano-phosphor can be applicable in the field of display devices and green laser.
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Affiliation(s)
- R S Yadav
- Laser & Spectroscopy Laboratory, Department of Physics, Banaras Hindu University, Varanasi 221 005, India
| | - R K Verma
- Laser & Spectroscopy Laboratory, Department of Physics, Banaras Hindu University, Varanasi 221 005, India
| | - A Bahadur
- Laser & Spectroscopy Laboratory, Department of Physics, Banaras Hindu University, Varanasi 221 005, India
| | - S B Rai
- Laser & Spectroscopy Laboratory, Department of Physics, Banaras Hindu University, Varanasi 221 005, India.
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Verma RK, Sankararamakrishnan R. Molecular Dynamics Simulations of Wild-Type and Mutant AQP6 Channels: Investigation of Anion Transport in Human AQP6. Biophys J 2015. [DOI: 10.1016/j.bpj.2014.11.2049] [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: 11/17/2022] Open
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Sharma P, Verma RK, Mishra R, Sahu AK, Choudhary DK, Gaur RK. First report of cucumber green mottle mosaic virus association with the leaf green mosaic disease of a vegetable crop, Luffa acutangula L. Acta Virol 2014; 58:299-300. [PMID: 25283869 DOI: 10.4149/av_2014_03_299] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
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Verma RK, Prabh ND, Sankararamakrishnan R. New subfamilies of major intrinsic proteins in fungi suggest novel transport properties in fungal channels: implications for the host-fungal interactions. BMC Evol Biol 2014; 14:173. [PMID: 25112373 PMCID: PMC4236510 DOI: 10.1186/s12862-014-0173-4] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/09/2014] [Accepted: 07/24/2014] [Indexed: 12/18/2022] Open
Abstract
Background Aquaporins (AQPs) and aquaglyceroporins (AQGPs) belong to the superfamily of Major Intrinsic Proteins (MIPs) and are involved in the transport of water and neutral solutes across the membranes. MIP channels play significant role in plant-fungi symbiotic relationship and are believed to be important in host-pathogen interactions in human fungal diseases. In plants, at least five major MIP subfamilies have been identified. Fungal MIP subfamilies include orthodox aquaporins and five subgroups within aquaglyceroporins. XIP subfamily is common to both plants and fungi. In this study, we have investigated the extent of diversity in fungal MIPs and explored further evolutionary relationships with the plant MIP counterparts. Results We have extensively analyzed the available fungal genomes and examined nearly 400 fungal MIPs. Phylogenetic analysis and homology modeling exhibit the existence of a new MIP cluster distinct from any of the known fungal MIP subfamilies. All members of this cluster are found in microsporidia which are unicellular fungal parasites. Members of this family are small in size, charged and have hydrophobic residues in the aromatic/arginine selectivity filter and these features are shared by small and basic intrinsic proteins (SIPs), one of the plant MIP subfamilies. We have also found two new subfamilies (δ and γ2) within the AQGP group. Fungal AQGPs are the most diverse and possess the largest number of subgroups. We have also identified distinguishing features in loops E and D in the newly identified subfamilies indicating their possible role in channel transport and gating. Conclusions Fungal SIP-like MIP family is distinct from any of the known fungal MIP families including orthodox aquaporins and aquaglyceroporins. After XIPs, this is the second MIP subfamily from fungi that may have possible evolutionary link with a plant MIP subfamily. AQGPs in fungi are more diverse and possess the largest number of subgroups. The aromatic/arginine selectivity filter of SIP-like fungal MIPs and the δ AQGPs are unique, hydrophobic in nature and are likely to transport novel hydrophobic solutes. They can be attractive targets for developing anti-fungal drugs. The evolutionary pattern shared with their plant counterparts indicates possible involvement of new fungal MIPs in plant-fungi symbiosis and host-pathogen interactions.
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Tripathi N, Verma RK, Panda NK, Ghosal S, Sharma A. Early evaluation of voice quality in glottic cancer (T1, T2) following curative radiotherapy. Rev Laryngol Otol Rhinol (Bord) 2014; 135:91-96. [PMID: 26521348] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 06/05/2023]
Abstract
BACKGROUND This is prospective study analyzing the subjective and objective quality of voice and voice related quality of life in patients of early glottic cancer (T1, T2 disease) before and after receiving curative radiotherapy. METHODS Fifteen patients of early glottic carcinoma (T1, T2) underwent voice assessment using multidimensional voice protocol based on recommendation by European Laryngological Society which included Perceptual analysis of voice by speech therapist and otolaryngologist, acoustic analysis; aerodynamic efficiency analysis-Maximum phonation time; patient's self perception of voice analysis--Voice handicap index; and videolaryngostroboscopy. Assessment was done prior to commencement of radiation therapy and at 1 month and 3 months following radio- therapy. RESULTS There was significant improvement in majority of the voice parameters post radiotherapy. Perceptual analysis showed significant improvement in GRBAS score following radiotherapy. Perturbation measures (jitter, shimmer, SNR, HNR) showed improvement post radiotherapy though remained inferior compared to controls. Mean fundamental frequency (Mean F0) and habitual frequency (habitual F0) decreased post radiotherapy. Intensity of voice increased following radiotherapy which was statistically significant (p < 0.05). There was significant improvement in the patient's perception of their quality of voice and voice related quality of life post radiotherapy. Maximum phonation time showed statistically significant improvement post-radiotherapy. Perceptual analysis of voice by professional observer correlated well with patients self perception of his own voice. CONCLUSION Voice quality improves following radiotherapy but not all the patients regain normal voice. Improvement in voice quality improves quality of life of patients shown by improved voice handicap index.
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Abstract
During routine dissection of the submental region of a 65-year-old female cadaver, a bilateral supernumerary muscle, medial to the anterior bellies of the digastric muscle, was observed. The accessory muscle bundle was attached proximally to the digastric fossa of the mandible, with an intermediate attachment to the body of hyoid bone and a distal attachment to the medial margin of the lower end of the anterior belly of the digastric muscle and its intermediate tendon on the respective side. These types of bilaterally symmetrical accessory muscles of the submental region may be erroneously identified as an infarcted submental lymph node or a pseudomass on radiological examinations.
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Affiliation(s)
- A Rani
- Department of Anatomy, King George’s Medical University, Lucknow, India.
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Yadav RV, Verma RK, Kaur G, Rai SB. Change in structural morphology on addition of ZnO and its effect on fluorescence of Yb³⁺/Er³⁺ doped Y₂O₃. Spectrochim Acta A Mol Biomol Spectrosc 2013; 103:216-221. [PMID: 23261616 DOI: 10.1016/j.saa.2012.10.054] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/19/2012] [Revised: 10/08/2012] [Accepted: 10/10/2012] [Indexed: 06/01/2023]
Abstract
Yb(3+)/Er(3+) codoped Y(2)O(3) phosphor and its composite with ZnO have been synthesized by combustion method. Morphology of the materials has been investigated using X-ray diffraction pattern (XRD) and scanning electron microscopy (SEM) techniques. XRD confirms the constituents as Y(2)O(3) and ZnO, with average crystallite size of 112 nm. On addition of ZnO, a small shifting in XRD pattern of Y(2)O(3) is observed. SEM pattern suggests that the average particle size lies in micro-range (0.5 μm). A dumble like structure is observed for hybrid material on annealing at 1473 K. A strong green (525, 546 nm) with weak blue (411 nm) and red (657 nm) emissions through upconversion has been observed from the phosphor on excitation with 976 nm diode laser. The observed emissions involve (2)H(9/2)→(4)I(15/2), (2)H(11/2)→(4)I(15/2), (4)S(3/2)→(4)I(15/2) and (4)F(9/2)→(4)I(15/2) electronic transitions, respectively. The upconversion process has been confirmed by power dependence measurements and its slope value was found to be 1.85, 1.72 for green and red emissions, respectively. On addition of ZnO, the intensity of these emissions is enhanced several times. The reason behind the enhancement is discussed with the help of the emitting level lifetime. An interesting dual mode property (upconversion and downconversion) to the same material has been observed on excitation with 532 nm laser source.
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Affiliation(s)
- R V Yadav
- Laser and Spectroscopy Laboratory, Department of Physics, Banaras Hindu University, Varanasi 221 005, India
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Rai M, Mishra K, Singh SK, Verma RK, Rai SB. Infrared to visible upconversion in Ho³+/Yb³+ co-doped Y₂ O₃ phosphor: effect of laser input power and external temperature. Spectrochim Acta A Mol Biomol Spectrosc 2012; 97:825-829. [PMID: 22902580 DOI: 10.1016/j.saa.2012.07.071] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/09/2012] [Revised: 07/14/2012] [Accepted: 07/17/2012] [Indexed: 06/01/2023]
Abstract
In the present paper, Ho(3+) doped and Ho(3+)/Yb(3+) co-doped Y(2)O(3) phosphors have been synthesized using solution combustion technique and characterized for its structure and upconversion (UC) fluorescence as a function of Yb(3+) concentration. Effect of a variation in laser input power and external temperature on the UC emission intensity has been studied to explore the UC mechanism and temperature dependent behavior of the phosphor, respectively. On excitation with near infrared (NIR) light (976 nm), the phosphor emits strong green emission along with relatively weak emission bands in red and blue regions at 553, 670 and 497 nm due to (5)S(2)→(5)I(8), (5)F(5)→(5)I(8) and (5)F(3)→(5)I(8), respectively. The emission shows a decrease in intensity with an increase in external temperature, however contrary to the normal behavior of Ho(3+), no significant change in the FIR (fluorescence intensity ratio) of (5)F(4)→(5)I(8) and (5)S(2)→(5)I(8) transitions is noted in the present host. This peculiar behavior of the sample with external temperature has been explained by temperature dependent lifetime study of the thermally coupled levels.
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Affiliation(s)
- Monika Rai
- Laser and Spectroscopy Laboratory, Department of Physics, Banaras Hindu University, Varanasi 221005, India
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Verma RS, Verma RK, Chauhan A, Yadav AK. Seasonal Variation in Essential Oil Content and Composition of Thyme, Thymus serpyllum L. Cultivated in Uttarakhand Hills. Indian J Pharm Sci 2012; 73:233-5. [PMID: 22303071 PMCID: PMC3267312 DOI: 10.4103/0250-474x.91570] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/19/2010] [Revised: 02/17/2011] [Accepted: 03/17/2011] [Indexed: 12/04/2022] Open
Abstract
Thymus serpyllum L. grown in Kumaon region of Western Himalaya was investigated for essential oil content and composition in different seasons. The oils of fresh samples were obtained by hydrodistillation. The yield of essential oil (% v/w) during different seasons varied from 0.07 to 0.28% with the highest in summer season, at vegetative stage. The oils were analyzed by GC and GC-MS. Major components of all the samples were thymol (19.4-60.1%), γ-terpinene (0.3-13.8%) and p-cymene (3.5-10.4%). The results clearly indicated that season has significant effect on quality and quantity of thyme oil.
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Affiliation(s)
- R S Verma
- Central Institute of Medicinal and Aromatic Plants (CIMAP, CSIR), Research Centre, Pantnagar, P.O.- Dairy Farm Nagla, Udham Singh Nagar, Uttarakhand-263 149, India
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Prasad R, Verma SK, Garg R, Jain A, Anand SC, Hosmane GB, Verma RK, Kushwaha NS, Kant S. Drug susceptibility pattern of Mycobacterium tuberculosis isolates from patients of category-II failure of pulmonary tuberculosis under directly observed treatment short-course from north India. Biosci Trends 2012; 6:110-4. [PMID: 22890158 DOI: 10.5582/bst.2012.v6.3.110] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/05/2022]
Abstract
The major contributing factors for the causation of treatment failure in cases of pulmonary tuberculosis under Category-II directly observed treatment short-course treatment (DOTS) are treatment after default, poor treatment compliance, and development of multi-drug resistant (MDR) tuberculosis. The objective of the present study is to find out the demographic profile and drug susceptibility pattern in Category-II failure patients of pulmonary tuberculosis under Revised National Tuberculosis Control Programme (RNTCP) of India. Two hundred and twenty four patients with Category-II treatment failure of pulmonary tuberculosis were enrolled from Department of Pulmonary Medicine, at Chatrapati Sahuji Maharaj Medical University, UP, Lucknow, India, from August 2003 to July 2008. Their complete bacteriological assessment in terms of sputum smear for acid-fast bacilli, culture for Mycobacterium tuberculosis and drug sensitivity pattern were done in the Department of Microbiology. Among 224 patients, 16 (7.1%) patients were lost to follow-up and the final analysis was done among 208 (92.8%) cases. The reasons for inclusion of these 224 cases in the Category II regimen were treatment failure in the previous regimen (n = 75, 33%), default in 57% (n = 129 cases), and relapse in 8.9% (n = 20 cases). Among 208 patients, culture was positive in 170 (81.7%) cases, negative in 17 (8.1%) cases and contaminated in 21 (10%) cases. The drug sensitivity pattern of culture positive cases of Category-II failure patients revealed that, 58.2% (n = 99) had MDR tuberculosis and 40.5% (n = 69) were resistant but were non-MDR tuberculosis and 1.1 % (n = 2) cases were sensitive to all first line antituberculosis drugs.
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Affiliation(s)
- R Prasad
- Department of Pulmonary Medicine, Chatrapati Sahuji Maharaj Medical University (Earlier KGMU), UP, Lucknow, India
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Kesavalu L, Lucas AR, Verma RK, Liu L, Dai E, Sampson E, Progulske-Fox A. Increased atherogenesis during Streptococcus mutans infection in ApoE-null mice. J Dent Res 2012; 91:255-60. [PMID: 22262633 DOI: 10.1177/0022034511435101] [Citation(s) in RCA: 51] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022] Open
Abstract
Streptococcus mutans, a dental caries pathogen, also causes endocarditis and is detected in atheroscelerotic plaque. We investigated the potential for an invasive strain of S. mutans, OMZ175, to accelerate plaque growth in apolipoprotein E deficient (ApoE(null)) mice without and with balloon angioplasty (BA) injury, a model of restenosis. ApoE(null) mice were divided into 4 groups (N = 10), 2 with and 2 without BA. One each of the BA and non-BA groups was infected with S. mutans (Sm). S. mutans DNA, plaque area, inflammatory cell invasion, and Toll-like receptor (TLR) expression were measured at 6-20 weeks post-infection. S. mutans genomic DNA was detected in the aorta, liver, spleen, and heart. Plaque growth was significantly increased in infected mice with BA (Sm+BA) vs. those in the non-infected groups (p < 0.03). Plaque size was increased after infection without BA (Sm), but did not reach significance. Aortic specimens from both S. mutans and Sm+BA groups displayed increased numbers of macrophages, and TLR4 expression was increased in BA mice. In conclusion, S. mutans infection accelerated plaque growth, macrophage invasion, and TLR4 expression after angioplasty. S. mutans may also be associated with atherosclerotic plaque growth in non-injured arteries.
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Affiliation(s)
- L Kesavalu
- Department of Periodontology, University of Florida, Gainesville, FL 32610-0424, USA.
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Kumar Verma R, Jain A, Sankararamakrishnan R. Distinguishing Features of Aquaglyceroporin in Plasmodium Falciparum: Comparative Molecular Dynamics Simulations of Three Aquaporins. Biophys J 2012. [DOI: 10.1016/j.bpj.2011.11.2478] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/27/2022] Open
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Gupta AB, Verma RK, Agarwal V, Vajpai M, Bansal V, Sankararamakrishnan R. MIPModDB: a central resource for the superfamily of major intrinsic proteins. Nucleic Acids Res 2012; 40:D362-9. [PMID: 22080560 PMCID: PMC3245135 DOI: 10.1093/nar/gkr914] [Citation(s) in RCA: 30] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/12/2011] [Revised: 10/05/2011] [Accepted: 10/08/2011] [Indexed: 12/23/2022] Open
Abstract
The channel proteins belonging to the major intrinsic proteins (MIP) superfamily are diverse and are found in all forms of life. Water-transporting aquaporin and glycerol-specific aquaglyceroporin are the prototype members of the MIP superfamily. MIPs have also been shown to transport other neutral molecules and gases across the membrane. They have internal homology and possess conserved sequence motifs. By analyzing a large number of publicly available genome sequences, we have identified more than 1000 MIPs from diverse organisms. We have developed a database MIPModDB which will be a unified resource for all MIPs. For each MIP entry, this database contains information about the source, gene structure, sequence features, substitutions in the conserved NPA motifs, structural model, the residues forming the selectivity filter and channel radius profile. For selected set of MIPs, it is possible to derive structure-based sequence alignment and evolutionary relationship. Sequences and structures of selected MIPs can be downloaded from MIPModDB database which is freely available at http://bioinfo.iitk.ac.in/MIPModDB.
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Affiliation(s)
- Anjali Bansal Gupta
- Department of Biological Sciences and Bioengineering, Indian Institute of Technology Kanpur, Kanpur 208016 and Department of Biotechnology, Indian Institute of Technology Roorkee, Roorkee 247667, India
| | - Ravi Kumar Verma
- Department of Biological Sciences and Bioengineering, Indian Institute of Technology Kanpur, Kanpur 208016 and Department of Biotechnology, Indian Institute of Technology Roorkee, Roorkee 247667, India
| | - Vatsal Agarwal
- Department of Biological Sciences and Bioengineering, Indian Institute of Technology Kanpur, Kanpur 208016 and Department of Biotechnology, Indian Institute of Technology Roorkee, Roorkee 247667, India
| | - Manu Vajpai
- Department of Biological Sciences and Bioengineering, Indian Institute of Technology Kanpur, Kanpur 208016 and Department of Biotechnology, Indian Institute of Technology Roorkee, Roorkee 247667, India
| | - Vivek Bansal
- Department of Biological Sciences and Bioengineering, Indian Institute of Technology Kanpur, Kanpur 208016 and Department of Biotechnology, Indian Institute of Technology Roorkee, Roorkee 247667, India
| | - Ramasubbu Sankararamakrishnan
- Department of Biological Sciences and Bioengineering, Indian Institute of Technology Kanpur, Kanpur 208016 and Department of Biotechnology, Indian Institute of Technology Roorkee, Roorkee 247667, India
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Bhagat S, Verma RK, Panda NK. Extranasopharyneal angiofibroma in an adult: a rare presentation. Indian J Otolaryngol Head Neck Surg 2011; 63:25-6. [PMID: 22754828 DOI: 10.1007/s12070-011-0178-x] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [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: 07/01/2008] [Accepted: 08/21/2008] [Indexed: 11/29/2022] Open
Abstract
Juvenile nasopharyngeal angiofibromas are benign but locally aggressive tumors of nasopharynx seen exclusively in adolescent males. Angiofibromas arising in sites other than nasopharynx is very rare. Maxilla is the most frequent site of origin. Extra nasopharyngeal angiofibromas of adult is extremely rare. We present a case of extra nasopharnygeal angiofibroma arising from maxillary sinus in an adult patient which was excised successfully.
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Affiliation(s)
- Sanjeev Bhagat
- Department of Otolaryngology, Head and Neck Surgery, Post Graduate Institute of Medical Education and Research, Chandigarh, 160012 India
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