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Zhang Y, Soubias O, Pant S, Heinrich F, Vogel A, Li J, Li Y, Clifton LA, Daum S, Bacia K, Huster D, Randazzo PA, Lösche M, Tajkhorshid E, Byrd RA. Myr-Arf1 conformational flexibility at the membrane surface sheds light on the interactions with ArfGAP ASAP1. Nat Commun 2023; 14:7570. [PMID: 37989735 PMCID: PMC10663523 DOI: 10.1038/s41467-023-43008-5] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [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: 05/12/2023] [Accepted: 10/30/2023] [Indexed: 11/23/2023] Open
Abstract
ADP-ribosylation factor 1 (Arf1) interacts with multiple cellular partners and membranes to regulate intracellular traffic, organelle structure and actin dynamics. Defining the dynamic conformational landscape of Arf1 in its active form, when bound to the membrane, is of high functional relevance and key to understanding how Arf1 can alter diverse cellular processes. Through concerted application of nuclear magnetic resonance (NMR), neutron reflectometry (NR) and molecular dynamics (MD) simulations, we show that, while Arf1 is anchored to the membrane through its N-terminal myristoylated amphipathic helix, the G domain explores a large conformational space, existing in a dynamic equilibrium between membrane-associated and membrane-distal conformations. These configurational dynamics expose different interfaces for interaction with effectors. Interaction with the Pleckstrin homology domain of ASAP1, an Arf-GTPase activating protein (ArfGAP), restricts motions of the G domain to lock it in what seems to be a conformation exposing functionally relevant regions.
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Affiliation(s)
- Yue Zhang
- Center for Structural Biology, Center for Cancer Research, National Cancer Institute, Frederick, MD, 21702-1201, USA
- Ring Therapeutics, Inc., Cambridge, MA, USA
| | - Olivier Soubias
- Center for Structural Biology, Center for Cancer Research, National Cancer Institute, Frederick, MD, 21702-1201, USA
| | - Shashank Pant
- Theoretical and Computational Biophysics Group, NIH Center for Macromolecular Modeling and Visualization, Beckman Institute for Advanced Science and Technology, Department of Biochemistry, and Center for Biophysics and Quantitative Biology, University of Illinois at Urbana-Champaign, Urbana, IL, 61801, USA
- Loxo Oncology at Lilly, Louisville, CO, USA
| | - Frank Heinrich
- Department of Physics, Carnegie Mellon University, Pittsburgh, PA, USA
- NIST Center for Neutron Research, Gaithersburg, MD, USA
| | - Alexander Vogel
- Institute of Medical Physics and Biophysics, University of Leipzig, 04107, Leipzig, Germany
| | - Jess Li
- Center for Structural Biology, Center for Cancer Research, National Cancer Institute, Frederick, MD, 21702-1201, USA
| | - Yifei Li
- Center for Structural Biology, Center for Cancer Research, National Cancer Institute, Frederick, MD, 21702-1201, USA
- Vonsun Pharmatech Co., Ltd., Suzhou, China
| | - Luke A Clifton
- ISIS Neutron and Muon Source, Rutherford Appleton Laboratory, Didcot, Oxfordshire, OX11 0QX, UK
| | - Sebastian Daum
- Institute for Chemistry, Department of Biophysical Chemistry, Martin Luther University Halle-Wittenberg, Kurt-Mothes-Str. 3A, 06120, Halle, Germany
| | - Kirsten Bacia
- Institute for Chemistry, Department of Biophysical Chemistry, Martin Luther University Halle-Wittenberg, Kurt-Mothes-Str. 3A, 06120, Halle, Germany
| | - Daniel Huster
- Institute of Medical Physics and Biophysics, University of Leipzig, 04107, Leipzig, Germany
| | - Paul A Randazzo
- Laboratory of Cellular and Molecular Biology, National Cancer Institute, National Institutes of Health, Bethesda, MD, 20892, USA
| | - Mathias Lösche
- Department of Physics, Carnegie Mellon University, Pittsburgh, PA, USA
- NIST Center for Neutron Research, Gaithersburg, MD, USA
- Department of Biomedical Engineering, Carnegie Mellon University, Pittsburgh, PA, USA
| | - Emad Tajkhorshid
- Theoretical and Computational Biophysics Group, NIH Center for Macromolecular Modeling and Visualization, Beckman Institute for Advanced Science and Technology, Department of Biochemistry, and Center for Biophysics and Quantitative Biology, University of Illinois at Urbana-Champaign, Urbana, IL, 61801, USA
| | - R Andrew Byrd
- Center for Structural Biology, Center for Cancer Research, National Cancer Institute, Frederick, MD, 21702-1201, USA.
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Baviskar Y, Likonda B, Pant S, Mokal S, Pawar A, Dasgupta A, Chatterjee A, Gupta T. Short-course Palliative Hypofractionated Radiotherapy in Patients with Poor-prognosis High-grade Glioma: Survival and Quality of Life Outcomes from a Prospective Phase II Study. Clin Oncol (R Coll Radiol) 2023; 35:e573-e581. [PMID: 37455146 DOI: 10.1016/j.clon.2023.07.001] [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] [Received: 02/17/2023] [Revised: 04/11/2023] [Accepted: 07/07/2023] [Indexed: 07/18/2023]
Abstract
AIMS To report longitudinal quality of life (QoL) outcomes and survival in patients with poor-prognosis high-grade glioma (HGG) treated with palliative hypofractionated radiotherapy. MATERIALS AND METHODS Patients with poor-prognosis HGG were accrued on a prospective study of short-course palliative hypofractionated radiotherapy (35 Gy/10 fractions/2 weeks). The European Organization for Research and Treatment of Cancer QoL core questionnaire (QLQ-C30) and brain cancer module (BN20) were used in English or validated Indian vernacular languages (Hindi and Marathi) for QoL assessment at baseline (before radiotherapy), the conclusion of radiotherapy, 1 month post-radiotherapy and subsequently at 3-monthly intervals until disease progression/death. Baseline QoL scores were compared with corresponding scores from a historical HGG cohort. Summary QoL scores were compared longitudinally over time by related samples Friedman's two-way test. Progression-free survival and overall survival were calculated using the Kaplan-Meier method and reported as 1-year estimates with 95% confidence intervals. RESULTS Forty-nine (89%) of 55 patients completed the planned course of hypofractionated radiotherapy. Longitudinal QoL data were available in 42 (86%) of 49 patients completing radiotherapy, comprising the present cohort. The median age of included patients, comprised mainly of glioblastoma patients (81%), was 57 years, with an interquartile range (IQR) of 50-66 years and a median baseline Karnofsky score of 60 (IQR = 50-60). Baseline QoL scores were significantly worse for several domains compared with a historical institutional cohort of HGG patients treated previously with conventionally fractionated radiotherapy, indicating negative selection bias. QoL scores remained stable for most domains after palliative hypofractionated radiotherapy, with statistically significant improvements in fatigue (P = 0.032), dyspnoea (P = 0.042) and motor dysfunction (P = 0.036) over time. At a median follow-up of 8 months, Kaplan-Meier estimates of 1-year progression-free survival and overall survival were 33.3% (95% confidence interval 21.7-51.1%) and 38.1% (95% confidence interval 25.9-56%), respectively. CONCLUSION Short-course palliative hypofractionated radiotherapy in patients with poor-prognosis HGG is associated with stable and/or improved QoL scores in several domains, making it a viable resource-sparing regimen.
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Affiliation(s)
- Y Baviskar
- Department of Radiation Oncology, Tata Memorial Hospital (TMH)/Advanced Centre for Treatment Research and Education in Cancer (ACTREC), Tata Memorial Centre, Homi Bhabha National Institute (HBNI), Mumbai, India
| | - B Likonda
- Department of Radiation Oncology, Tata Memorial Hospital (TMH)/Advanced Centre for Treatment Research and Education in Cancer (ACTREC), Tata Memorial Centre, Homi Bhabha National Institute (HBNI), Mumbai, India
| | - S Pant
- Department of Radiation Oncology, Tata Memorial Hospital (TMH)/Advanced Centre for Treatment Research and Education in Cancer (ACTREC), Tata Memorial Centre, Homi Bhabha National Institute (HBNI), Mumbai, India
| | - S Mokal
- Department of Clinical Research Secretariat, Tata Memorial Hospital (TMH)/Advanced Centre for Treatment Research and Education in Cancer (ACTREC), Tata Memorial Centre, Homi Bhabha National Institute (HBNI), Mumbai, India
| | - A Pawar
- Department of Clinical Research Secretariat, Tata Memorial Hospital (TMH)/Advanced Centre for Treatment Research and Education in Cancer (ACTREC), Tata Memorial Centre, Homi Bhabha National Institute (HBNI), Mumbai, India
| | - A Dasgupta
- Department of Radiation Oncology, Tata Memorial Hospital (TMH)/Advanced Centre for Treatment Research and Education in Cancer (ACTREC), Tata Memorial Centre, Homi Bhabha National Institute (HBNI), Mumbai, India
| | - A Chatterjee
- Department of Radiation Oncology, Tata Memorial Hospital (TMH)/Advanced Centre for Treatment Research and Education in Cancer (ACTREC), Tata Memorial Centre, Homi Bhabha National Institute (HBNI), Mumbai, India
| | - T Gupta
- Department of Radiation Oncology, Tata Memorial Hospital (TMH)/Advanced Centre for Treatment Research and Education in Cancer (ACTREC), Tata Memorial Centre, Homi Bhabha National Institute (HBNI), Mumbai, India.
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Pant S, Jena NR. Repurposing of antiparasitic drugs against the NS2B-NS3 protease of the Zika virus. J Biomol Struct Dyn 2023:1-13. [PMID: 37747074 DOI: 10.1080/07391102.2023.2255648] [Citation(s) in RCA: 0] [Impact Index Per Article: 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: 02/23/2023] [Accepted: 08/28/2023] [Indexed: 09/26/2023]
Abstract
To date, no approved drugs are available to treat the Zika virus (ZIKV) infection. Therefore, it is necessary to urgently identify potential drugs against the ZIKV infection. Here, the repurposing of 30 antiparasitic drugs against the NS2B-NS3 protease of the ZIKV has been carried out by using combined docking and molecular dynamics- (MD) simulations. Based on the docking results, 5 drugs, such as Amodiaquine, Primaquine, Paromomycin, Dichlorophene, and Ivermectin were screened for further analysis by MD simulations and free energy calculations. Among these drugs, Amodiaquine and Dichlorophen are found to produce the most stable complexes and possess relative binding free energies of about -44.3 ± 3.7 kcal/mol and -41.1 ± 5.3 kcal/mol respectively. Therefore, they would act as potent small-molecule inhibitors of the ZIKV protease.However, evaluations of biological and safety activities of these drugs against the ZIKV protease are required before their clinical use.Communicated by Ramaswamy H. Sarma.
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Affiliation(s)
- S Pant
- Department of Pharmacoinformatics, National Institute of Pharmaceutical Education and Research, Kolkata, India
| | - N R Jena
- Discipline of Natural Sciences, Indian Institute of Information Technology, Design and Manufacturing, Jabalpur, India
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Subbiah V, Pant S. Translating immuno-onco-microbiome-based therapeutics: precision bugs for immune checkpoint drugs! Ann Oncol 2023; 34:503-506. [PMID: 37295905 DOI: 10.1016/j.annonc.2023.03.002] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/07/2023] [Accepted: 03/08/2023] [Indexed: 06/12/2023] Open
Affiliation(s)
- V Subbiah
- Department of Investigational Cancer Therapeutics, Division of Cancer Medicine, The University of Texas MD Anderson Cancer Center, Houston, USA.
| | - S Pant
- Department of GI Medical Oncology, Division of Cancer Medicine, The University of Texas MD Anderson Cancer Center, Houston, USA.
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Wu Q, Akhter A, Pant S, Cho E, Zhu JX, Garner A, Ohyama T, Tajkhorshid E, van Meyel D, Ryan RM. Ataxia-linked SLC1A3 mutations alter EAAT1 chloride channel activity and glial regulation of CNS function. Biophys J 2023; 122:465a. [PMID: 36784387 DOI: 10.1016/j.bpj.2022.11.2495] [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: 02/12/2023] Open
Affiliation(s)
- Qianyi Wu
- Physiology and Biophysics, Weill Cornell Medicine, New York, NY, USA
| | | | - Shashank Pant
- University of Illinois Urbana-Champaign, Champaign, IL, USA
| | | | - Jin X Zhu
- McGill University, Montreal, QC, Canada
| | | | | | - Emad Tajkhorshid
- Biochemistry, University of Illinois Urbana-Champaign, Urbana, IL, USA
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Le LTM, Thompson JR, Dehghani‐Ghahnaviyeh S, Pant S, Dang PX, French JB, Kanikeyo T, Tajkhorshid E, Alam A. Cryo-EM structures of human ABCA7 provide insights into its phospholipid translocation mechanisms. EMBO J 2023; 42:e111065. [PMID: 36484366 PMCID: PMC9890230 DOI: 10.15252/embj.2022111065] [Citation(s) in RCA: 0] [Impact Index Per Article: 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: 03/02/2022] [Revised: 11/07/2022] [Accepted: 11/10/2022] [Indexed: 12/13/2022] Open
Abstract
Phospholipid extrusion by ABC subfamily A (ABCA) exporters is central to cellular physiology, although the specifics of the underlying substrate interactions and transport mechanisms remain poorly resolved at the molecular level. Here we report cryo-EM structures of lipid-embedded human ABCA7 in an open state and in a nucleotide-bound, closed state at resolutions between 3.6 and 4.0 Å. The former reveals an ordered patch of bilayer lipids traversing the transmembrane domain (TMD), while the latter reveals a lipid-free, closed TMD with a small extracellular opening. These structures offer a structural framework for both substrate entry and exit from the ABCA7 TMD and highlight conserved rigid-body motions that underlie the associated conformational transitions. Combined with functional analysis and molecular dynamics (MD) simulations, our data also shed light on lipid partitioning into the ABCA7 TMD and localized membrane perturbations that underlie ABCA7 function and have broader implications for other ABCA family transporters.
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Affiliation(s)
- Le Thi My Le
- The Hormel InstituteUniversity of MinnesotaAustinMNUSA
| | | | - Sepehr Dehghani‐Ghahnaviyeh
- Theoretical and Computational Biophysics Group, NIH Center for Macromolecular Modeling and Bioinformatics, Beckman Institute for Advanced Science and Technology, Department of Biochemistry, and Center for Biophysics and Quantitative BiologyUniversity of Illinois at Urbana‐ChampaignUrbanaILUSA
| | - Shashank Pant
- Theoretical and Computational Biophysics Group, NIH Center for Macromolecular Modeling and Bioinformatics, Beckman Institute for Advanced Science and Technology, Department of Biochemistry, and Center for Biophysics and Quantitative BiologyUniversity of Illinois at Urbana‐ChampaignUrbanaILUSA
- Present address:
Loxo Oncology at LillyLouisvilleCOUSA
| | | | | | | | - Emad Tajkhorshid
- Theoretical and Computational Biophysics Group, NIH Center for Macromolecular Modeling and Bioinformatics, Beckman Institute for Advanced Science and Technology, Department of Biochemistry, and Center for Biophysics and Quantitative BiologyUniversity of Illinois at Urbana‐ChampaignUrbanaILUSA
| | - Amer Alam
- The Hormel InstituteUniversity of MinnesotaAustinMNUSA
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Singaram I, Sharma A, Pant S, Lihan M, Park MJ, Pergande M, Buwaneka P, Hu Y, Mahmud N, Kim YM, Cologna S, Gevorgyan V, Khan I, Tajkhorshid E, Cho W. Targeting lipid-protein interaction to treat Syk-mediated acute myeloid leukemia. Nat Chem Biol 2023; 19:239-250. [PMID: 36229686 PMCID: PMC9898191 DOI: 10.1038/s41589-022-01150-z] [Citation(s) in RCA: 9] [Impact Index Per Article: 9.0] [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: 09/27/2021] [Accepted: 08/25/2022] [Indexed: 02/06/2023]
Abstract
Membrane lipids control the cellular activity of kinases containing the Src homology 2 (SH2) domain through direct lipid-SH2 domain interactions. Here we report development of new nonlipidic small molecule inhibitors of the lipid-SH2 domain interaction that block the cellular activity of their host proteins. As a pilot study, we evaluated the efficacy of lipid-SH2 domain interaction inhibitors for spleen tyrosine kinase (Syk), which is implicated in hematopoietic malignancies, including acute myeloid leukemia (AML). An optimized inhibitor (WC36) specifically and potently suppressed oncogenic activities of Syk in AML cell lines and patient-derived AML cells. Unlike ATP-competitive Syk inhibitors, WC36 was refractory to de novo and acquired drug resistance due to its ability to block not only the Syk kinase activity, but also its noncatalytic scaffolding function that is linked to drug resistance. Collectively, our study shows that targeting lipid-protein interaction is a powerful approach to developing new small molecule drugs.
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Affiliation(s)
- Indira Singaram
- Department of Chemistry, University of Illinois Chicago, Chicago, IL 60607, U.S.A
| | - Ashutosh Sharma
- Department of Chemistry, University of Illinois Chicago, Chicago, IL 60607, U.S.A
| | - Shashank Pant
- NIH Center for Macromolecular Modeling and Bioinformatics, Beckman Institute for Advanced Science and Technology, Department of Biochemistry, Center for Biophysics and Quantitative Biology, University of Illinois Urbana-Champaign, Urbana, IL 61801, USA
| | - Muyun Lihan
- NIH Center for Macromolecular Modeling and Bioinformatics, Beckman Institute for Advanced Science and Technology, Department of Biochemistry, Center for Biophysics and Quantitative Biology, University of Illinois Urbana-Champaign, Urbana, IL 61801, USA
| | - Mi-Jeong Park
- Department of Integrative Biosciences and Biotechnology, Pohang University of Science and Technology, Pohang 37673, Republic of Korea
| | - Melissa Pergande
- Department of Chemistry, University of Illinois Chicago, Chicago, IL 60607, U.S.A
| | - Pawanthi Buwaneka
- Department of Chemistry, University of Illinois Chicago, Chicago, IL 60607, U.S.A
| | - Yusi Hu
- Department of Chemistry, University of Illinois Chicago, Chicago, IL 60607, U.S.A
| | - Nadim Mahmud
- Department of Medicine, University of Illinois Chicago, Chicago, IL 60612, U.S.A
| | - You-Me Kim
- Graduate School of Medical Science and Engineering, Korea Advanced Institute of Science and Technology, Daejeon 34141, Republic of Korea
| | - Stephanie Cologna
- Department of Chemistry, University of Illinois Chicago, Chicago, IL 60607, U.S.A
| | - Vladimir Gevorgyan
- Department of Chemistry, University of Texas at Dallas, Dallas, TX 75080, U.S.A
| | - Irum Khan
- Department of Medicine, University of Illinois Chicago, Chicago, IL 60612, U.S.A
| | - Emad Tajkhorshid
- NIH Center for Macromolecular Modeling and Bioinformatics, Beckman Institute for Advanced Science and Technology, Department of Biochemistry, Center for Biophysics and Quantitative Biology, University of Illinois Urbana-Champaign, Urbana, IL 61801, USA
| | - Wonhwa Cho
- Department of Chemistry, University of Illinois Chicago (UIC), Chicago, IL, USA.
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Bernard V, Elhammali A, Lin D, Pant S, Tzeng C, Bhutani M, Maitra A, Navin N, Taniguchi C. Single Cell Sequencing of Pancreatic Ductal Adenocarcinoma Reveals a Paradoxical Immunosuppressive Microenvironment Following Stereotactic Body Radiation Therapy. Int J Radiat Oncol Biol Phys 2022. [DOI: 10.1016/j.ijrobp.2022.07.1098] [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: 11/16/2022]
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Yap T, Ngoi N, Dumbrava E, Karp D, Rodon Ahnert J, Fu S, Hong D, Naing A, Pant S, Piha-Paul S, Subbiah V, Tsimberidou A, Dufner D, Rhudy J, Gore S, Ivy S, Yuan Y, Westin S, Mills G, Meric-Bernstam F. NCI10329: Phase Ib Sequential Trial of Agents against DNA Repair (STAR) Study to investigate the sequential combination of the Poly (ADP-Ribose) Polymerase inhibitor (PARPi) olaparib (ola) and WEE1 inhibitor (WEE1i) adavosertib (ada) in patients (pts) with DNA Damage Response (DDR)-aberrant advanced tumors, enriched for BRCA1/2 mutated and CCNE1 amplified cancers. Eur J Cancer 2022. [DOI: 10.1016/s0959-8049(22)00822-x] [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: 11/03/2022]
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Ngoi N, Pilie P, Piha-Paul S, Dumbrava E, Fu S, Hong D, Karp D, Naing A, Pant S, Rodon Ahnert J, Subbiah V, Tsimberidou A, Salguero C, Brown C, Hoadley W, Johnson A, Yuan Y, Westin S, Meric-Bernstam F, Yap T. DNA Damage Response (DDR) Basket of Baskets (D-BOB) Trial: Phase 1/2 Study of the ATR inhibitor (ATRi) berzosertib and PD-L1 inhibitor avelumab in patients (pts) with advanced solid tumors with DDR molecular alterations. Eur J Cancer 2022. [DOI: 10.1016/s0959-8049(22)00828-0] [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: 11/03/2022]
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Tervonen T, Belitskin D, Munne P, Pant S, Anttila J, Belitskina K, Pouwels J, Klefström J. Hepsin promotes breast tumor growth signaling via TGF beta-EGFR axis. Eur J Cancer 2022. [DOI: 10.1016/s0959-8049(22)01058-9] [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: 11/27/2022]
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Ngoi N, Lin H, Ileana Dumbrava E, Fu S, Karp D, Naing A, Pant S, Rodon J, Piha-Paul S, Subbiah V, Tsimberidou A, Campbell E, Urrutia S, Hong D, Meric-Bernstam F, Yuan Y, Yap T. 485P Correlation of clinical, genomic and hematological parameters with ATR inhibitor (ATRi) outcomes in phase I/II clinical trials. Ann Oncol 2022. [DOI: 10.1016/j.annonc.2022.07.613] [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: 11/01/2022] Open
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Harding J, Hofheinz R, Elez Fernandez M, Kuboki Y, Rasco D, Cecchini M, Shen L, Archuadze S, Geng J, Haderk F, Pant S. 371P A phase Ia/b, open-label, multicentre study of the TRAILR2 agonist BI 905711 in patients (pts) with advanced gastrointestinal (GI) cancers. Ann Oncol 2022. [DOI: 10.1016/j.annonc.2022.07.509] [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: 11/01/2022] Open
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Massard C, Cassier PA, Azaro A, Anderson B, Yuen E, Yu D, Oakley G, Benhadji KA, Pant S. A phase 1b study of crenigacestat (LY3039478) in combination with gemcitabine and cisplatin or gemcitabine and carboplatin in patients with advanced or metastatic solid tumors. Cancer Chemother Pharmacol 2022; 90:335-344. [DOI: 10.1007/s00280-022-04461-z] [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] [Received: 07/20/2021] [Accepted: 08/02/2022] [Indexed: 11/28/2022]
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Naing A, Mamdani H, Barve M, Johnson M, Wolff R, Kim D, Yang S, Lee B, Adebanjo T, Georgevitch R, Ferrando-Martinez S, Haymaker C, Chaney M, Fan J, Kim R, Pant S. P-48 Phase 2a study of NT-I7, a long-acting interleukin-7, plus pembrolizumab: Cohort of subjects with checkpoint inhibitor-naïve advanced pancreatic cancer. Ann Oncol 2022. [DOI: 10.1016/j.annonc.2022.04.138] [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: 11/01/2022] Open
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Mehdi S, Wang D, Pant S, Tiwary P. Accelerating All-Atom Simulations and Gaining Mechanistic Understanding of Biophysical Systems through State Predictive Information Bottleneck. J Chem Theory Comput 2022; 18:3231-3238. [PMID: 35384668 DOI: 10.1021/acs.jctc.2c00058] [Citation(s) in RCA: 20] [Impact Index Per Article: 10.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/10/2023]
Abstract
An effective implementation of enhanced sampling algorithms for molecular dynamics simulations requires a priori knowledge of the approximate reaction coordinate describing the relevant mechanisms in the system. In this work, we focus on the recently developed artificial intelligence-based State Predictive Information Bottleneck (SPIB) approach and demonstrate how SPIB can learn such a reaction coordinate as a deep neural network even from undersampled trajectories. We exemplify its usefulness by achieving more than 40 times acceleration in simulating two model biophysical systems through well-tempered metadynamics performed by biasing along the SPIB-learned reaction coordinate. These include left- to right-handed chirality transitions in a synthetic helical peptide (Aib)9 and permeation of a small benzoic acid molecule through a synthetic, symmetric phospholipid bilayer. In addition to significantly accelerating the dynamics and achieving back and forth movement between different metastable states, the SPIB-based reaction coordinate gives mechanistic insights into the processes driving these two important problems.
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Affiliation(s)
- Shams Mehdi
- Biophysics Program and Institute for Physical Science and Technology, University of Maryland, College Park, Maryland 20742, United States
| | - Dedi Wang
- Biophysics Program and Institute for Physical Science and Technology, University of Maryland, College Park, Maryland 20742, United States
| | - Shashank Pant
- Center for Biophysics and Quantitative Biology, Beckman Institute for Advanced Science and Technology, University of Illinois at Urbana-Champaign, Urbana, Illinois 61801, United States
| | - Pratyush Tiwary
- Department of Chemistry and Biochemistry and Institute for Physical Science and Technology, University of Maryland, College Park, Maryland 20742, United States
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Pant S, Wu Q, Ryan R, Tajkhorshid E. Microscopic Characterization of the Chloride Permeation Pathway in the Human Excitatory Amino Acid Transporter 1 (EAAT1). ACS Chem Neurosci 2022; 13:776-785. [PMID: 35192345 PMCID: PMC9725111 DOI: 10.1021/acschemneuro.1c00769] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022] Open
Abstract
Excitatory amino acid transporters (EAATs) are glutamate transporters that belong to the solute carrier 1A (SLC1A) family. They couple glutamate transport to the cotransport of three sodium (Na+) ions and one proton (H+) and the counter-transport of one potassium (K+) ion. In addition to this coupled transport, binding of cotransported species to EAATs activates a thermodynamically uncoupled chloride (Cl-) conductance. Structures of SLC1A family members have revealed that these transporters use a twisting elevator mechanism of transport, where a mobile transport domain carries substrate and coupled ions across the membrane, while a static scaffold domain anchors the transporter in the membrane. We recently demonstrated that the uncoupled Cl- conductance is activated by the formation of an aqueous pore at the domain interface during the transport cycle in archaeal GltPh. However, a pathway for the uncoupled Cl- conductance has not been reported for the EAATs, and it is unclear if such a pathway is conserved. Here, we employ all-atom molecular dynamics (MD) simulations combined with enhanced sampling, free-energy calculations, and experimental mutagenesis to approximate large-scale conformational changes during the transport process and identified a Cl--conducting conformation in human EAAT1 (hEAAT1). Sampling the large-scale structural transitions in hEAAT1 allowed us to capture an intermediate conformation formed during the transport cycle with a continuous aqueous pore at the domain interface. The free-energy calculations performed for the conduction of Cl- and Na+ ions through the captured conformation highlight the presence of two hydrophobic gates that control low-barrier movement of Cl- through the aqueous pathway. Overall, our findings provide insights into the mechanism by which a human neurotransmitter transporter supports functional duality of active transport and passive Cl- permeation and confirm the commonality of this mechanism in different members of the SLC1A family.
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Affiliation(s)
- Shashank Pant
- Theoretical and Computational Biophysics Group, NIH Center for Macromolecular Modeling and Bioinformatics, Beckman Institute for Advanced Science and Technology, Department of Biochemistry, and Center for Biophysics and Quantitative Biology, University of Illinois at Urbana-Champaign, Urbana, Illinois 61801, United States
| | - Qianyi Wu
- School of Medical Sciences, Faculty of Medicine and Health, University of Sydney, Camperdown, New South Wales 2006, Australia
| | - Renae Ryan
- School of Medical Sciences, Faculty of Medicine and Health, University of Sydney, Camperdown, New South Wales 2006, Australia
| | - Emad Tajkhorshid
- Theoretical and Computational Biophysics Group, NIH Center for Macromolecular Modeling and Bioinformatics, Beckman Institute for Advanced Science and Technology, Department of Biochemistry, and Center for Biophysics and Quantitative Biology, University of Illinois at Urbana-Champaign, Urbana, Illinois 61801, United States
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18
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Chen H, Ogden D, Pant S, Cai W, Tajkhorshid E, Moradi M, Roux B, Chipot C. A Companion Guide to the String Method with Swarms of Trajectories: Characterization, Performance, and Pitfalls. J Chem Theory Comput 2022; 18:1406-1422. [PMID: 35138832 PMCID: PMC8904302 DOI: 10.1021/acs.jctc.1c01049] [Citation(s) in RCA: 8] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/09/2023]
Abstract
The string method with swarms of trajectories (SMwST) is an algorithm that identifies a physically meaningful transition pathway─a one-dimensional curve, embedded within a high-dimensional space of selected collective variables. The SMwST algorithm leans on a series of short, unbiased molecular dynamics simulations spawned at different locations of the discretized path, from whence an average dynamic drift is determined to evolve the string toward an optimal pathway. However conceptually simple in both its theoretical formulation and practical implementation, the SMwST algorithm is computationally intensive and requires a careful choice of parameters for optimal cost-effectiveness in applications to challenging problems in chemistry and biology. In this contribution, the SMwST algorithm is presented in a self-contained manner, discussing with a critical eye its theoretical underpinnings, applicability, inherent limitations, and use in the context of path-following free-energy calculations and their possible extension to kinetics modeling. Through multiple simulations of a prototypical polypeptide, combining the search of the transition pathway and the computation of the potential of mean force along it, several practical aspects of the methodology are examined with the objective of optimizing the computational effort, yet without sacrificing accuracy. In light of the results reported here, we propose some general guidelines aimed at improving the efficiency and reliability of the computed pathways and free-energy profiles underlying the conformational transitions at hand.
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Affiliation(s)
- Haochuan Chen
- Research Center for Analytical Sciences, College of Chemistry, Tianjin Key Laboratory of Biosensing and Molecular Recognition, Nankai University, Tianjin 300071, China
- Theoretical and Computational Biophysics Group, NIH Center for Macromolecular Modeling and Bioinformatics, Beckman Institute for Advanced Science and Technology, University of Illinois at Urbana-Champaign, Urbana, Illinois 61801, United States
- Laboratoire International Associé Centre National de la Recherche Scientifique et University of Illinois at Urbana-Champaign, Unité Mixte de Recherche no 7019, Université de Lorraine, B.P. 70239, 54506 Vandœuvre-lès-Nancy Cedex, France
| | - Dylan Ogden
- Department of Chemistry and Biochemistry, University of Arkansas, Fayetteville, Arkansas 72701, United States
| | - Shashank Pant
- Theoretical and Computational Biophysics Group, NIH Center for Macromolecular Modeling and Bioinformatics, Beckman Institute for Advanced Science and Technology, University of Illinois at Urbana-Champaign, Urbana, Illinois 61801, United States
| | - Wensheng Cai
- Research Center for Analytical Sciences, College of Chemistry, Tianjin Key Laboratory of Biosensing and Molecular Recognition, Nankai University, Tianjin 300071, China
| | - Emad Tajkhorshid
- Theoretical and Computational Biophysics Group, NIH Center for Macromolecular Modeling and Bioinformatics, Beckman Institute for Advanced Science and Technology, University of Illinois at Urbana-Champaign, Urbana, Illinois 61801, United States
- Department of Biochemistry and Center for Biophysics and Quantitative Biology, University of Illinois at Urbana-Champaign, Urbana, Illinois 61801, United States
| | - Mahmoud Moradi
- Department of Chemistry and Biochemistry, University of Arkansas, Fayetteville, Arkansas 72701, United States
| | - Benoît Roux
- Department of Biochemistry and Molecular Biology, University of Chicago, Chicago, Illinois 60637, United States
| | - Christophe Chipot
- Theoretical and Computational Biophysics Group, NIH Center for Macromolecular Modeling and Bioinformatics, Beckman Institute for Advanced Science and Technology, University of Illinois at Urbana-Champaign, Urbana, Illinois 61801, United States
- Laboratoire International Associé Centre National de la Recherche Scientifique et University of Illinois at Urbana-Champaign, Unité Mixte de Recherche no 7019, Université de Lorraine, B.P. 70239, 54506 Vandœuvre-lès-Nancy Cedex, France
- Department of Physics, University of Illinois at Urbana-Champaign, Urbana, Illinois 61801, United States
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19
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Pant S, Bhattacharya G, Jena NR. Structures and dynamics of peptide and peptidomimetic inhibitors bound to the NS2B-NS3 protease of the ZIKA virus. J Biomol Struct Dyn 2022; 41:3076-3088. [PMID: 35238272 DOI: 10.1080/07391102.2022.2045223] [Citation(s) in RCA: 0] [Impact Index Per Article: 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] [Indexed: 10/18/2022]
Abstract
Infections caused by the Zika virus (ZIKV) have detrimental effects on human health, in particular on infants. As no potent drug or vaccine is available to date to contain this viral disease, it is necessary to design inhibitors that can target the NS2B-NS3 protease of the ZIKV, which is mainly responsible for the proliferation of the virus inside the host cells . Here, molecular dynamics (MD) simulation and molecular mechanics energies combined with the generalized Born and surface area continuum solvation model (MM/GBSA) are used to understand the binding modes and stabilities of R, KR, KKR, WKR, WKKR, YKKR, and FKKR peptide inhibitors bound to the NS3-NS2B protease. The results are compared with the corresponding results obtained for covalent (compound 1) and non-covalent (compound 4*) peptidomimetic inhibitors . It is revealed that peptide inhibitors can bind strongly with the ZIKV protease with the ΔGbind ranging from -12 kcal/mol to -73 kcal/mol. Among these peptides, YKKR is found to make the most stable complex with the protease and fully occupy the electrostatically active substrate binding site. Hence, it would inhibit the protease activities of ZIKV strongly. The residue-wise decomposition of ΔGbind indicates that Asp75, Asp129, Tyr130, Ser135, Gly151, Asn152, Glys153, and Tyr161 of NS3 and Ser81, Asp83, and Phe84 of NS2B play a prominent role in the inhibitor binding. Therefore, any future design of inhibitors should be aimed to target these residues.
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Affiliation(s)
- S Pant
- Department of Pharmacoinformatics, National Institute of Pharmaceutical Education and Research, Kolkata, India
| | - G Bhattacharya
- Discipline of Natural Sciences, Indian Institute of Information Technology, Design and Manufacturing, Jabalpur, India
| | - N R Jena
- Discipline of Natural Sciences, Indian Institute of Information Technology, Design and Manufacturing, Jabalpur, India
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20
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Adhikari P, Pahari R, Joshi S, Acharya S, Pant S. An unusual presentation of liver abscess secondary to toxoplasmosis in Nepal. Int J Infect Dis 2022. [DOI: 10.1016/j.ijid.2021.12.173] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022] Open
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21
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Wu Q, Akhter A, Pant S, Cho E, Zhu JX, Garner AR, Ohyama T, Tajkhorshid E, van Meyel DJ, Ryan RM. Ataxia-linked SLC1A3 mutations alter EAAT1 chloride channel activity and glial regulation of CNS function. J Clin Invest 2022; 132:154891. [PMID: 35167492 PMCID: PMC8970671 DOI: 10.1172/jci154891] [Citation(s) in RCA: 5] [Impact Index Per Article: 2.5] [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: 09/10/2021] [Accepted: 02/08/2022] [Indexed: 11/17/2022] Open
Abstract
Glutamate is the predominant excitatory neurotransmitter in the mammalian central nervous system (CNS). Excitatory Amino Acid Transporters (EAATs) regulate extracellular glutamate by transporting it into cells, mostly glia, to terminate neurotransmission and to avoid neurotoxicity. EAATs are also chloride (Cl-) channels, but the physiological role of Cl- conductance through EAATs is poorly understood. Mutations of human EAAT1 (hEAAT1) have been identified in patients with episodic ataxia type 6 (EA6). One mutation showed increased Cl- channel activity and decreased glutamate transport, but the relative contributions of each function of hEAAT1 to mechanisms underlying the pathology of EA6 remain unclear. Here we investigated the effects of five additional EA6-related mutations on hEAAT1 function in Xenopus laevis oocytes, and on CNS function in a Drosophila melanogaster model of locomotor behavior. Our results indicate that mutations resulting in decreased hEAAT1 Cl- channel activity but with functional glutamate transport can also contribute to the pathology of EA6, highlighting the importance of Cl- homeostasis in glial cells for proper CNS function. We also identified a novel mechanism involving an ectopic sodium (Na+) leak conductance in glial cells. Together, these results strongly support the idea that EA6 is primarily an ion channelopathy of CNS glia.
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Affiliation(s)
- Qianyi Wu
- School of Medical Sciences, University of Sydney, Sydney, Australia
| | - Azman Akhter
- Department of Neurology and Neurosurgery, McGill University, Montreal, Canada
| | - Shashank Pant
- Theoretical and Computational Biophysics Group, University of Illinois at Urbana-Champaign, Urbana, United States of America
| | - Eunjoo Cho
- Department of Neurology and Neurosurgery, McGill University, Montreal, Canada
| | - Jin Xin Zhu
- Department of Neurology and Neurosurgery, McGill University, Montreal, Canada
| | | | - Tomoko Ohyama
- Department of Biology, McGill University, Montreal, Canada
| | - Emad Tajkhorshid
- Theoretical and Computational Biophysics Group, University of Illinois at Urbana-Champaign, Urbana, United States of America
| | - Donald J van Meyel
- Department of Neurology and Neurosurgery, McGill University, Montreal, Canada
| | - Renae M Ryan
- School of Medical Sciences, University of Sydney, Sydney, Australia
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22
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Gullett JM, Cuypers MG, Grace CR, Pant S, Subramanian C, Tajkhorshid E, Rock CO, White SW. Identification of Structural transitions in bacterial fatty acid binding proteins that permit ligand entry and exit at membranes. J Biol Chem 2022; 298:101676. [PMID: 35122790 PMCID: PMC8892158 DOI: 10.1016/j.jbc.2022.101676] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [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: 10/19/2021] [Revised: 01/26/2022] [Accepted: 01/28/2022] [Indexed: 12/31/2022] Open
Abstract
Fatty acid (FA) transfer proteins extract FA from membranes and sequester them to facilitate their movement through the cytosol. Detailed structural information is available for these soluble protein–FA complexes, but the structure of the protein conformation responsible for FA exchange at the membrane is unknown. Staphylococcus aureus FakB1 is a prototypical bacterial FA transfer protein that binds palmitate within a narrow, buried tunnel. Here, we define the conformational change from a “closed” FakB1 state to an “open” state that associates with the membrane and provides a path for entry and egress of the FA. Using NMR spectroscopy, we identified a conformationally flexible dynamic region in FakB1, and X-ray crystallography of FakB1 mutants captured the conformation of the open state. In addition, molecular dynamics simulations show that the new amphipathic α-helix formed in the open state inserts below the phosphate plane of the bilayer to create a diffusion channel for the hydrophobic FA tail to access the hydrocarbon core and place the carboxyl group at the phosphate layer. The membrane binding and catalytic properties of site-directed mutants were consistent with the proposed membrane docked structure predicted by our molecular dynamics simulations. Finally, the structure of the bilayer-associated conformation of FakB1 has local similarities with mammalian FA binding proteins and provides a conceptual framework for how these proteins interact with the membrane to create a diffusion channel from the FA location in the bilayer to the protein interior.
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Affiliation(s)
- Jessica M Gullett
- Departments of Infectious Diseases, St. Jude Children's Research Hospital, Memphis, TN 38105, USA
| | - Maxime G Cuypers
- Departments of Structural Biology, St. Jude Children's Research Hospital, Memphis, TN 38105, USA
| | - Christy R Grace
- Departments of Structural Biology, St. Jude Children's Research Hospital, Memphis, TN 38105, USA
| | - Shashank Pant
- Theoretical and Computational Biophysics Group, NIH Center for Macromolecular Modeling and Bioinformatics, Beckman Institute for Advanced Science and Technology, Department of Biochemistry, and Center for Biophysics and Quantitative Biology, University of Illinois at Urbana-Champaign, Urbana, IL 61801, USA
| | - Chitra Subramanian
- Departments of Infectious Diseases, St. Jude Children's Research Hospital, Memphis, TN 38105, USA
| | - Emad Tajkhorshid
- Theoretical and Computational Biophysics Group, NIH Center for Macromolecular Modeling and Bioinformatics, Beckman Institute for Advanced Science and Technology, Department of Biochemistry, and Center for Biophysics and Quantitative Biology, University of Illinois at Urbana-Champaign, Urbana, IL 61801, USA
| | - Charles O Rock
- Departments of Infectious Diseases, St. Jude Children's Research Hospital, Memphis, TN 38105, USA.
| | - Stephen W White
- Departments of Structural Biology, St. Jude Children's Research Hospital, Memphis, TN 38105, USA.
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23
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Zhang Y, Soubias O, Pant S, Heinrich F, Vogel A, Li J, Huster D, Randazzo P, Losche M, Tajkhorshid E, Byrd RA. Myr-Arf1 conformational flexibility at the membrane surface: insights for its interactions with ASAP1. Biophys J 2022. [DOI: 10.1016/j.bpj.2021.11.465] [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: 11/02/2022] Open
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24
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Soubias O, Pant S, Zhang Y, Tajkhorshid E, Byrd RA. Probing the PIP2 dependence of the ASAP1 PH domain membrane binding by NMR and MD simulations. Biophys J 2022. [DOI: 10.1016/j.bpj.2021.11.2300] [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: 11/02/2022] Open
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25
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Thunshelle C, Chowdhury T, Zaid M, Jaoude JA, Dai A, Kirimli E, Prakash L, Katz M, Tzeng C, Kim M, Wolff R, Pant S, Smaglo B, Ludmir E, Holliday E, Das P, Minsky B, Taniguchi C, Koong A, Koay E. Effect of Radiotherapy (RT) on Outcomes in Patients (Pts) With Borderline Resectable and Locally Advanced Pancreatic Ductal Adenocarcinoma (BRPC, LAPC). Int J Radiat Oncol Biol Phys 2021. [DOI: 10.1016/j.ijrobp.2021.07.329] [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: 10/20/2022]
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26
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Gupta T, Pant S, Likonda B, Dasgupta A, Chatterjee A, Kannan S, Sastri G, Trivedi S, Dutta D, Jalali R. Comparison of Two Palliative Hypofractionated Radiotherapy Regimens in Poor-Prognosis High-Grade Glioma: A Propensity-Matched Analysis. Int J Radiat Oncol Biol Phys 2021. [DOI: 10.1016/j.ijrobp.2021.07.1580] [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]
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27
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Parra E, Adriani M, Freitas Pinto Lima C, Li J, Haymaker C, Parikh R, Bernicker E, Davar D, Chaudhry A, Stevenson A, Badham C, Fyvie G, Chisamore M, Pant S. 1024P Baseline biomarkers associated with clinical benefit in patients with solid tumors refractory to immune checkpoint inhibitors (ICIs) treated with live biotherapeutic MRx0518 in combination with pembrolizumab. Ann Oncol 2021. [DOI: 10.1016/j.annonc.2021.08.1408] [Citation(s) in RCA: 1] [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: 11/26/2022] Open
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28
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Borazanci E, Al Hallak M, Eder J, Golan T, Pant S, Perets R, Markel G, Schickler M, Reuveni H, Jin L, Liang B. 1027TiP A phase Ib study of CM24 in combination with nivolumab in adults with advanced solid tumors, followed by a phase IIa study of CM24 in combination with nivolumab in NSCLC, and in combination with nivolumab and nab-paclitaxel in pancreatic cancer. Ann Oncol 2021. [DOI: 10.1016/j.annonc.2021.08.1411] [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: 11/16/2022] Open
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29
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Bengs M, Pant S, Bockmayr M, Schüller U, Schlaefer A. Multi-Scale Input Strategies for Medulloblastoma Tumor Classification using Deep Transfer Learning. Current Directions in Biomedical Engineering 2021. [DOI: 10.1515/cdbme-2021-1014] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022] Open
Abstract
Abstract
Medulloblastoma (MB) is a primary central nervous system tumor and the most common malignant brain cancer among children. Neuropathologists perform microscopic inspection of histopathological tissue slides under a microscope to assess the severity of the tumor. This is a timeconsuming task and often infused with observer variability. Recently, pre-trained convolutional neural networks (CNN) have shown promising results for MB subtype classification. Typically, high-resolution images are divided into smaller tiles for classification, while the size of the tiles has not been systematically evaluated. We study the impact of tile size and input strategy and classify the two major histopathological subtypes-Classic and Desmoplastic/Nodular. To this end, we use recently proposed EfficientNets and evaluate tiles with increasing size combined with various downsampling scales. Our results demonstrate using large input tiles pixels followed by intermediate downsampling and patch cropping significantly improves MB classification performance. Our top-performing method achieves the AUC-ROC value of 90.90% compared to 84.53% using the previous approach with smaller input tiles.
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Affiliation(s)
- M. Bengs
- Institute of Medical Technology and Intelligent Systems, Hamburg University of Technology, Hamburg , Germany
| | - S. Pant
- Institute of Medical Technology and Intelligent Systems, Hamburg University of Technology, Hamburg , Germany
| | - M. Bockmayr
- Department of Pediatric Hematology and Oncology, University Medical Center Hamburg-Eppendorf, Martinistraße 52, Hamburg 20246, Germany
- Research Institute Children’s Cancer Center Hamburg, Martinistraße 52, Hamburg 20251, Germany
- Mildred Scheel Cancer Career Center HaTriCS4, University Medical Center Hamburg-Eppendorf, 20246 Hamburg , Germany
| | - U. Schüller
- Department of Pediatric Hematology and Oncology, University Medical Center Hamburg-Eppendorf, Martinistraße 52, Hamburg 20246, Germany
- Research Institute Children’s Cancer Center Hamburg, Martinistraße 52, Hamburg 20251, Germany
- Institute of Neuropathology, University Medical Center Hamburg-Eppendorf, Martinistraße 52, Hamburg 20246, Germany
| | - A. Schlaefer
- Institute of Medical Technology and Intelligent Systems, Hamburg University of Technology, Hamburg , Germany
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30
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Jones G, Parr J, Nithiarasu P, Pant S. Machine learning for detection of stenoses and aneurysms: application in a physiologically realistic virtual patient database. Biomech Model Mechanobiol 2021; 20:2097-2146. [PMID: 34333696 PMCID: PMC8595223 DOI: 10.1007/s10237-021-01497-7] [Citation(s) in RCA: 12] [Impact Index Per Article: 4.0] [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: 03/11/2021] [Accepted: 07/12/2021] [Indexed: 11/27/2022]
Abstract
This study presents an application of machine learning (ML) methods for detecting the presence of stenoses and aneurysms in the human arterial system. Four major forms of arterial disease-carotid artery stenosis (CAS), subclavian artery stenosis (SAS), peripheral arterial disease (PAD), and abdominal aortic aneurysms (AAA)-are considered. The ML methods are trained and tested on a physiologically realistic virtual patient database (VPD) containing 28,868 healthy subjects, adapted from the authors previous work and augmented to include disease. It is found that the tree-based methods of Random Forest and Gradient Boosting outperform other approaches. The performance of ML methods is quantified through the [Formula: see text] score and computation of sensitivities and specificities. When using six haemodynamic measurements (pressure in the common carotid, brachial, and radial arteries; and flow-rate in the common carotid, brachial, and femoral arteries), it is found that maximum [Formula: see text] scores larger than 0.9 are achieved for CAS and PAD, larger than 0.85 for SAS, and larger than 0.98 for both low- and high-severity AAAs. Corresponding sensitivities and specificities are larger than 90% for CAS and PAD, larger than 85% for SAS, and larger than 98% for both low- and high-severity AAAs. When reducing the number of measurements, performance is degraded by less than 5% when three measurements are used, and less than 10% when only two measurements are used for classification. For AAA, it is shown that [Formula: see text] scores larger than 0.85 and corresponding sensitivities and specificities larger than 85% are achievable when using only a single measurement. The results are encouraging to pursue AAA monitoring and screening through wearable devices which can reliably measure pressure or flow-rates.
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Affiliation(s)
- G Jones
- Faculty of Science and Engineering, Swansea University, Swansea, UK
| | - J Parr
- McLaren Technology Centre, Woking, UK
| | - P Nithiarasu
- Faculty of Science and Engineering, Swansea University, Swansea, UK
| | - S Pant
- Faculty of Science and Engineering, Swansea University, Swansea, UK.
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31
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Kapoor K, Pant S, Tajkhorshid E. Active participation of membrane lipids in inhibition of multidrug transporter P-glycoprotein. Chem Sci 2021; 12:6293-6306. [PMID: 34084427 PMCID: PMC8115088 DOI: 10.1039/d0sc06288j] [Citation(s) in RCA: 16] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/15/2020] [Accepted: 03/31/2021] [Indexed: 01/04/2023] Open
Abstract
P-glycoprotein (Pgp) is a major efflux pump in humans, overexpressed in a variety of cancers and associated with the development of multi-drug resistance. Allosteric modulation by various ligands (e.g., transport substrates, inhibitors, and ATP) has been biochemically shown to directly influence structural dynamics, and thereby, the function of Pgp. However, the molecular details of such effects, particularly with respect to the role and involvement of the surrounding lipids, are not well established. Here, we employ all-atom molecular dynamics (MD) simulations to study the conformational landscape of Pgp in the presence of a high-affinity, third-generation inhibitor, tariquidar, in comparison to the nucleotide-free (APO) and the ATP-bound states, in order to characterize the mechanical effects of the inhibitor that might be of relevance to its blocking mechanism of Pgp. Simulations in a multi-component lipid bilayer show a dynamic equilibrium between open(er) and more closed inward-facing (IF) conformations in the APO state, with binding of ATP shifting the equilibrium towards conformations more prone to ATP hydrolysis and subsequent events in the transport cycle. In the presence of the inhibitor bound to the drug-binding pocket within the transmembrane domain (TMD), Pgp samples more open IF conformations, and the nucleotide binding domains (NBDs) become highly dynamic. Interestingly, and reproduced in multiple independent simulations, the inhibitor is observed to facilitate recruitment of lipid molecules into the Pgp lumen through the two proposed drug-entry portals, where the lipid head groups from the cytoplasmic leaflet penetrate into and, in some cases, translocate inside the TMD, while the lipid tails remain extended into the bulk lipid environment. These "wedge" lipids likely enhance the inhibitor-induced conformational restriction of the TMD leading to the differential modulation of coupling pathways observed with the NBDs downstream. We suggest a novel inhibitory mechanism for tariquidar, and potentially for related third-generation Pgp inhibitors, where lipids are seen to enhance the inhibitory role in the catalytic cycle of membrane transporters.
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Affiliation(s)
- Karan Kapoor
- NIH Center for Macromolecular Modeling and Bioinformatics, Beckman Institute for Advanced Science and Technology, Department of Biochemistry, Center for Biophysics and Quantitative Biology, University of Illinois at Urbana-Champaign Urbana IL 61801 USA
| | - Shashank Pant
- NIH Center for Macromolecular Modeling and Bioinformatics, Beckman Institute for Advanced Science and Technology, Department of Biochemistry, Center for Biophysics and Quantitative Biology, University of Illinois at Urbana-Champaign Urbana IL 61801 USA
| | - Emad Tajkhorshid
- NIH Center for Macromolecular Modeling and Bioinformatics, Beckman Institute for Advanced Science and Technology, Department of Biochemistry, Center for Biophysics and Quantitative Biology, University of Illinois at Urbana-Champaign Urbana IL 61801 USA
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32
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Chen I, Pant S, Wu Q, Cater R, Sobti M, Vandenberg R, Stewart AG, Tajkhorshid E, Font J, Ryan R. Glutamate transporters have a chloride channel with two hydrophobic gates. Nature 2021; 591:327-331. [PMID: 33597752 PMCID: PMC7954978 DOI: 10.1038/s41586-021-03240-9] [Citation(s) in RCA: 31] [Impact Index Per Article: 10.3] [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: 05/25/2020] [Accepted: 01/13/2021] [Indexed: 01/31/2023]
Abstract
Glutamate is the most abundant excitatory neurotransmitter in the central nervous system, and its precise control is vital to maintain normal brain function and to prevent excitotoxicity1. The removal of extracellular glutamate is achieved by plasma-membrane-bound transporters, which couple glutamate transport to sodium, potassium and pH gradients using an elevator mechanism2-5. Glutamate transporters also conduct chloride ions by means of a channel-like process that is thermodynamically uncoupled from transport6-8. However, the molecular mechanisms that enable these dual-function transporters to carry out two seemingly contradictory roles are unknown. Here we report the cryo-electron microscopy structure of a glutamate transporter homologue in an open-channel state, which reveals an aqueous cavity that is formed during the glutamate transport cycle. The functional properties of this cavity, combined with molecular dynamics simulations, reveal it to be an aqueous-accessible chloride permeation pathway that is gated by two hydrophobic regions and is conserved across mammalian and archaeal glutamate transporters. Our findings provide insight into the mechanism by which glutamate transporters support their dual function, and add information that will assist in mapping the complete transport cycle shared by the solute carrier 1A transporter family.
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Affiliation(s)
- Ichia Chen
- Transporter Biology Group, School of Medical Sciences, Faculty of Medicine and Health, University of Sydney, NSW, Australia
| | - Shashank Pant
- NIH Center for Macromolecular Modeling and Bioinformatics, Beckman Institute for Advanced Science and Technology, Department of Biochemistry, and Center for Biophysics and Quantitative Biology, University of Illinois at Urbana-Champaign, Urbana, IL 61801, USA
| | - Qianyi Wu
- Transporter Biology Group, School of Medical Sciences, Faculty of Medicine and Health, University of Sydney, NSW, Australia
| | - Rosemary Cater
- Transporter Biology Group, School of Medical Sciences, Faculty of Medicine and Health, University of Sydney, NSW, Australia
| | - Meghna Sobti
- Molecular, Structural and Computational Biology Division, The Victor Chang Cardiac Research Institute, Darlinghurst, NSW 2010, Australia.,St Vincent’s Clinical School, Faculty of Medicine, UNSW Sydney, Kensington, NSW 2052, Australia
| | - Robert Vandenberg
- Transporter Biology Group, School of Medical Sciences, Faculty of Medicine and Health, University of Sydney, NSW, Australia
| | - Alastair G. Stewart
- Molecular, Structural and Computational Biology Division, The Victor Chang Cardiac Research Institute, Darlinghurst, NSW 2010, Australia.,St Vincent’s Clinical School, Faculty of Medicine, UNSW Sydney, Kensington, NSW 2052, Australia
| | - Emad Tajkhorshid
- NIH Center for Macromolecular Modeling and Bioinformatics, Beckman Institute for Advanced Science and Technology, Department of Biochemistry, and Center for Biophysics and Quantitative Biology, University of Illinois at Urbana-Champaign, Urbana, IL 61801, USA, Corresponding authors: Emad Tajkhorshid (), Josep Font (), Renae Ryan ()
| | - Josep Font
- Transporter Biology Group, School of Medical Sciences, Faculty of Medicine and Health, University of Sydney, NSW, Australia, Corresponding authors: Emad Tajkhorshid (), Josep Font (), Renae Ryan ()
| | - Renae Ryan
- Transporter Biology Group, School of Medical Sciences, Faculty of Medicine and Health, University of Sydney, NSW, Australia, Corresponding authors: Emad Tajkhorshid (), Josep Font (), Renae Ryan ()
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Pant S, Nooralishahi P, Avdelidis NP, Ibarra-Castanedo C, Genest M, Deane S, Valdes JJ, Zolotas A, Maldague XPV. Evaluation and Selection of Video Stabilization Techniques for UAV-Based Active Infrared Thermography Application. Sensors (Basel) 2021; 21:s21051604. [PMID: 33668881 PMCID: PMC7956756 DOI: 10.3390/s21051604] [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] [Subscribe] [Scholar Register] [Received: 12/23/2020] [Revised: 02/03/2021] [Accepted: 02/15/2021] [Indexed: 11/16/2022]
Abstract
Unmanned Aerial Vehicles (UAVs) that can fly around an aircraft carrying several sensors, e.g., thermal and optical cameras, to inspect the parts of interest without removing them can have significant impact in reducing inspection time and cost. One of the main challenges in the UAV based active InfraRed Thermography (IRT) inspection is the UAV’s unexpected motions. Since active thermography is mainly concerned with the analysis of thermal sequences, unexpected motions can disturb the thermal profiling and cause data misinterpretation especially for providing an automated process pipeline of such inspections. Additionally, in the scenarios where post-analysis is intended to be applied by an inspector, the UAV’s unexpected motions can increase the risk of human error, data misinterpretation, and incorrect characterization of possible defects. Therefore, post-processing is required to minimize/eliminate such undesired motions using digital video stabilization techniques. There are number of video stabilization algorithms that are readily available; however, selecting the best suited one is also challenging. Therefore, this paper evaluates video stabilization algorithms to minimize/mitigate undesired UAV motion and proposes a simple method to find the best suited stabilization algorithm as a fundamental first step towards a fully operational UAV-IRT inspection system.
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Affiliation(s)
- Shashank Pant
- National Research Council Canada, Ottawa, ON K1A 0R6, Canada; (M.G.); (J.J.V.)
- Correspondence:
| | - Parham Nooralishahi
- Computer Vision and Systems Laboratory (CVSL), Department of Electrical and Computer Engineering, Laval University, Quebec City, QC G1V 0A6, Canada; (P.N.); (N.P.A.); (C.I.-C.); (X.P.V.M.)
| | - Nicolas P. Avdelidis
- Computer Vision and Systems Laboratory (CVSL), Department of Electrical and Computer Engineering, Laval University, Quebec City, QC G1V 0A6, Canada; (P.N.); (N.P.A.); (C.I.-C.); (X.P.V.M.)
- School of Aerospace, Transport and Manufacturing, Cranfield University, Cranfield MK43 0AL, UK; (S.D.); (A.Z.)
| | - Clemente Ibarra-Castanedo
- Computer Vision and Systems Laboratory (CVSL), Department of Electrical and Computer Engineering, Laval University, Quebec City, QC G1V 0A6, Canada; (P.N.); (N.P.A.); (C.I.-C.); (X.P.V.M.)
| | - Marc Genest
- National Research Council Canada, Ottawa, ON K1A 0R6, Canada; (M.G.); (J.J.V.)
| | - Shakeb Deane
- School of Aerospace, Transport and Manufacturing, Cranfield University, Cranfield MK43 0AL, UK; (S.D.); (A.Z.)
| | - Julio J. Valdes
- National Research Council Canada, Ottawa, ON K1A 0R6, Canada; (M.G.); (J.J.V.)
| | - Argyrios Zolotas
- School of Aerospace, Transport and Manufacturing, Cranfield University, Cranfield MK43 0AL, UK; (S.D.); (A.Z.)
| | - Xavier P. V. Maldague
- Computer Vision and Systems Laboratory (CVSL), Department of Electrical and Computer Engineering, Laval University, Quebec City, QC G1V 0A6, Canada; (P.N.); (N.P.A.); (C.I.-C.); (X.P.V.M.)
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Shrestha B, Neupane AK, Pant S, Shrestha A, Bastola A, Rajbhandari B, Thapa A, Singh A. Sensitivity and Specificity of Lateral Flow Antigen Test Kits for COVID-19 in Asymptomatic Population of Quarantine Centre of Province 3. Kathmandu Univ Med J (KUMJ) 2021; 18:36-39. [PMID: 33605236] [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] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/12/2023]
Abstract
Background Nearly after 6 months of the spread of Corona Virus Disease 19, along with the world Nepal is still trying to control the spread and prevent general population from acquiring it. With limited resources in manpower, technology and evidence it has been a difficult battle. But with time and more understanding of the virus new technology to detect the virus are coming up. It is a major breakthrough in the diagnostic field as this helps us in not only detecting the virus but also helps us to mobilize our human resources. This comes in a time where the cases are increasing at an alarming rate. Although numbers of Polymerase Chain Reaction testing have increased but due to the time consuming and the cost wise, we need a faster and equally reliable alternative. Antigen test approved by different countries can be used for point of care, screening and surveillance depending upon the requirements after calculating its sensitivity, specificity and accuracy. Objective To find out sensitivity and specificity of the Antigen test kit for COVID-19. Method Antigen tests were compared with Reverse Transcription Polymerase Chain Reaction as a reference standard in calculated sample size of 113 subjects in a high risk population. Both Reverse Transcription Polymerase Chain Reaction and antigen test were performed in a same subject with in maximum of 2 days' interval. Convenience sampling technique was used to select the subjects. Ethical approval was taken from Nepal Health Research Council before data collection. Study was done from August to September 2020 from Quarantine center of Province 3. Result There were total of 113 test carried out, among those 47 were positive and 66 were negative in Reverse Transcription Polymerase Chain Reaction. After preparing two by two table, Sensitivity and specificity of the tested was calculated which came out to be 85% and 100% respectively, with accuracy of 93.80%. Conclusion Even though the sensitivity and specificity came to be higher, this test should be interpreted cautiously depending upon the prevalence of Corona Virus Disease 19 in that particular community and the clinical and epidemiological context of the person who has been tested. When in doubt by clinical correlation should be confirmed with Reverse Transcription Polymerase Chain Reaction.
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Affiliation(s)
- B Shrestha
- Nepalese Army Institute of Health Sciences, Kathmandu, Nepal
| | - A K Neupane
- Nepalese Army Institute of Health Sciences, Kathmandu, Nepal
| | - S Pant
- Nepal Health Research Council, Kathmandu, Nepal
| | - A Shrestha
- Patan Academy of Health Science, Lalitpur, Patan, Nepal
| | - A Bastola
- Shukraraaj Tropical and Infectious Disease Hospital, Kathmandu, Nepal
| | | | - A Thapa
- Nepal Armed Police Force Hospital, Kathmandu, Nepal
| | - A Singh
- Nepalese Army Institute of Health Sciences, Kathmandu, Nepal
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Pant S, Chen I, Wu Q, Cater R, Sobti M, Vandenberg RJ, Stewart AG, Font J, Ryan RM, Tajkhorshid E. A Novel Chloride Conducting Conformation in Human Glutamate Transporters. Biophys J 2021. [DOI: 10.1016/j.bpj.2020.11.1209] [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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Chen I, Pant S, Wu Q, Cater RJ, Sobti M, Vandenberg RJ, Stewart A, Font J, Tajkhorshid E, Ryan RM. Glutamate Transporters (EAATS) Contain a Conserved Chloride Channel with Two Hydrophobic Gates. Biophys J 2021. [DOI: 10.1016/j.bpj.2020.11.846] [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: 10/22/2022] Open
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37
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Soubias O, Pant S, Heinrich F, Zhang Y, Randazzo P, Loesche M, Tajkhorshid E, Byrd RA. Membrane Surface Recognition by the ASAP1 Ph Domain and Consequences for Interactions with the Small GTPASE ARF1. Biophys J 2021. [DOI: 10.1016/j.bpj.2020.11.887] [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: 10/22/2022] Open
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Pant S, Smith Z, Wang Y, Tajkhorshid E, Tiwary P. Confronting pitfalls of AI-augmented molecular dynamics using statistical physics. J Chem Phys 2020; 153:234118. [PMID: 33353347 PMCID: PMC7863682 DOI: 10.1063/5.0030931] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/25/2020] [Accepted: 11/29/2020] [Indexed: 12/31/2022] Open
Abstract
Artificial intelligence (AI)-based approaches have had indubitable impact across the sciences through the ability to extract relevant information from raw data. Recently, AI has also found use in enhancing the efficiency of molecular simulations, wherein AI derived slow modes are used to accelerate the simulation in targeted ways. However, while typical fields where AI is used are characterized by a plethora of data, molecular simulations, per construction, suffer from limited sampling and thus limited data. As such, the use of AI in molecular simulations can suffer from a dangerous situation where the AI-optimization could get stuck in spurious regimes, leading to incorrect characterization of the reaction coordinate (RC) for the problem at hand. When such an incorrect RC is then used to perform additional simulations, one could start to deviate progressively from the ground truth. To deal with this problem of spurious AI-solutions, here, we report a novel and automated algorithm using ideas from statistical mechanics. It is based on the notion that a more reliable AI-solution will be one that maximizes the timescale separation between slow and fast processes. To learn this timescale separation even from limited data, we use a maximum caliber-based framework. We show the applicability of this automatic protocol for three classic benchmark problems, namely, the conformational dynamics of a model peptide, ligand-unbinding from a protein, and folding/unfolding energy landscape of the C-terminal domain of protein G. We believe that our work will lead to increased and robust use of trustworthy AI in molecular simulations of complex systems.
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Affiliation(s)
- Shashank Pant
- NIH Center for Macromolecular Modeling and Bioinformatics, Beckman Institute for Advanced Science and Technology, Department of Biochemistry, Center for Biophysics and Quantitative Biology, University of Illinois at Urbana-Champaign, Urbana, Illinois 61801, USA
| | | | | | - Emad Tajkhorshid
- NIH Center for Macromolecular Modeling and Bioinformatics, Beckman Institute for Advanced Science and Technology, Department of Biochemistry, Center for Biophysics and Quantitative Biology, University of Illinois at Urbana-Champaign, Urbana, Illinois 61801, USA
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Pant S, Dimri A, Arora R, Bachani S, Raisuddin S, Siraj F, Rastogi S. Chlamydia trachomatis infection predisposes to ectopic pregnancy by regulating expression of tetraspanins in fallopian tube: A pilot study. Int J Infect Dis 2020. [DOI: 10.1016/j.ijid.2020.09.1171] [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] Open
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40
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Dimri A, Pant S, Arora R, Bachani S, Parvez S, Siraj F, Rastogi S. Differential expression of Chlamydia trachomatis heat shock protein 60-encoding genes in tubal ectopic pregnancy. Int J Infect Dis 2020. [DOI: 10.1016/j.ijid.2020.09.1166] [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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41
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Hoffe S, Frakes JM, Aguilera TA, Czito B, Palta M, Brookes M, Schweizer C, Colbert L, Moningi S, Bhutani MS, Pant S, Tzeng CW, Tidwell RS, Thall P, Yuan Y, Moser EC, Holmlund J, Herman J, Taniguchi CM. Randomized, Double-Blinded, Placebo-controlled Multicenter Adaptive Phase 1-2 Trial of GC 4419, a Dismutase Mimetic, in Combination with High Dose Stereotactic Body Radiation Therapy (SBRT) in Locally Advanced Pancreatic Cancer (PC). Int J Radiat Oncol Biol Phys 2020; 108:1399-1400. [PMID: 33427657 DOI: 10.1016/j.ijrobp.2020.09.022] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Affiliation(s)
- S Hoffe
- H. Lee Moffitt Cancer Center and Research Institute, Department of Radiation Oncology, Tampa, FL
| | - J M Frakes
- H. Lee Moffitt Cancer Center and Research Institute, Department of Radiation Oncology, Tampa, FL
| | - T A Aguilera
- Department of Radiation Oncology, University of Texas Southwestern Medical Center, Dallas, TX
| | - B Czito
- Duke University Medical Center, Durham, NC
| | - M Palta
- Duke University Medical Center, Department of Radiation Oncology, Durham, NC
| | | | | | - L Colbert
- The University of Texas MD Anderson Cancer Center, Houston, TX
| | - S Moningi
- Johns Hopkins University School of Medicine, Baltimore, MD
| | | | - S Pant
- (10)University of Oklahoma Health Science Center, Stephenson Cancer Center, Department of Hematology & Oncology, Oklahoma City, OK
| | - C W Tzeng
- (11)The Univ of Texas MD Anderson Cancer Center, Houston, TX
| | - R S Tidwell
- (12)MD Anderson Cancer Center, Department of Biostatistics, Houston, TX
| | - P Thall
- (13)Department of Biostatistics, The University of Texas MD Anderson Cancer Center, Houston, TX
| | - Y Yuan
- MD Anderson Cancer Center, Houston, TX
| | | | - J Holmlund
- (14)Galera Therapeutics Inc., Malvern, PA
| | - J Herman
- (15)Northwell Health Cancer Institute, Lake Success, NY
| | - C M Taniguchi
- (16)UT MD Anderson Cancer Center, Houston, TX; (17)Department of Radiation Oncology, The University of Texas MD Anderson Cancer Center, Houston, TX
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Thein K, Tsimberidou A, Piha-Paul S, Janku F, Karp D, Fu S, Zarifa A, Gong J, Hong D, Yap T, Subbiah V, Pant S, Meric-Bernstam F, Naing A. 72MO Selinexor in combination with standard chemotherapy in patients with advanced solid tumours: Results of an open label, single-center, multi-arm phase Ib study. Ann Oncol 2020. [DOI: 10.1016/j.annonc.2020.10.092] [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: 10/22/2022] Open
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Thein K, Tsimberidou A, Piha-Paul S, Janku F, Karp D, Fu S, Zarifa A, Gong J, Yap T, Hong D, Subbiah V, Pant S, Meric-Bernstam F, Naing A. 73P Selinexor in combination with carboplatin and pemetrexed (CP) in patients with advanced or metastatic solid tumors: Results of an open label, single-center, multi-arm phase Ib study. Ann Oncol 2020. [DOI: 10.1016/j.annonc.2020.10.093] [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: 10/22/2022] Open
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Klaer P, Huang A, Sévigny P, Rajan S, Pant S, Patnaik P, Balaji B. An Investigation of Rotary Drone HERM Line Spectrum under Manoeuvering Conditions. Sensors (Basel) 2020; 20:s20205940. [PMID: 33096637 PMCID: PMC7590031 DOI: 10.3390/s20205940] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 08/12/2020] [Revised: 10/06/2020] [Accepted: 10/14/2020] [Indexed: 11/16/2022]
Abstract
Detecting and identifying drones is of great interest due to the proliferation of highly manoeuverable drones with on-board sensors of increasing sensing capabilities. In this paper, we investigate the use of radars for tackling this problem. In particular, we focus on the problem of detecting rotary drones and distinguishing between single-propeller and multi-propeller drones using a micro-Doppler analysis. Two different radars were used, an ultra wideband (UWB) continuous wave (CW) C-band radar and an automotive frequency modulated continuous wave (FMCW) W-band radar, to collect micro-Doppler signatures of the drones. By taking a closer look at HElicopter Rotor Modulation (HERM) lines, the spool and chopping lines are identified for the first time in the context of drones to determine the number of propeller blades. Furthermore, a new multi-frequency analysis method using HERM lines is developed, which allows the detection of propeller rotation rates (spool and chopping frequencies) of single and multi-propeller drones. Therefore, the presented method is a promising technique to aid in the classification of drones.
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Affiliation(s)
- Peter Klaer
- Defence Research and Development Canada, 3701 Carling Avenue, Ottawa, ON K2K 2Y7, Canada; (P.K.); (A.H.); (P.S.)
| | - Andi Huang
- Defence Research and Development Canada, 3701 Carling Avenue, Ottawa, ON K2K 2Y7, Canada; (P.K.); (A.H.); (P.S.)
- Department of Systems and Computer Engineering, Carleton University, 1125 Colonel By Drive, Ottawa, ON K1S 5B6, Canada;
| | - Pascale Sévigny
- Defence Research and Development Canada, 3701 Carling Avenue, Ottawa, ON K2K 2Y7, Canada; (P.K.); (A.H.); (P.S.)
| | - Sreeraman Rajan
- Department of Systems and Computer Engineering, Carleton University, 1125 Colonel By Drive, Ottawa, ON K1S 5B6, Canada;
| | - Shashank Pant
- Aerospace Research Centre, National Research Council Canada, 1200 Montreal Rd., Ottawa, ON K1A 0R6, Canada; (S.P.); (P.P.)
| | - Prakash Patnaik
- Aerospace Research Centre, National Research Council Canada, 1200 Montreal Rd., Ottawa, ON K1A 0R6, Canada; (S.P.); (P.P.)
| | - Bhashyam Balaji
- Defence Research and Development Canada, 3701 Carling Avenue, Ottawa, ON K2K 2Y7, Canada; (P.K.); (A.H.); (P.S.)
- Correspondence:
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Gouda M, Huang H, Piha-Paul S, Call S, Karp D, Fu S, Naing A, Subbiah V, Pant S, Tsimberidou A, Hong D, Rodon J, Meric-Bernstam F. Circulating Tumor DNA Dynamics Predict Outcomes of Systemic Therapy in Patients with Advanced Cancers. Eur J Cancer 2020. [DOI: 10.1016/s0959-8049(20)31079-0] [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: 10/23/2022]
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46
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Thein K, Tsimberidou A, Piha-Paul S, Janku F, Karp D, Fu S, Zarifa A, Gong J, Hong D, Yap T, Subbiah V, Pant S, Meric-Bernstam F, Naing A. 565P Selinexor in combination with topotecan in patients with advanced or metastatic solid tumours: Results of an open label, single-center, multi-arm phase Ib study. Ann Oncol 2020. [DOI: 10.1016/j.annonc.2020.08.679] [Citation(s) in RCA: 1] [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: 11/26/2022] Open
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47
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Schuler M, Tabernero J, Massard C, Iyer GV, Witt O, Doi T, Qin S, Lu-Emerson C, Hargrave D, Garcia-Corbacho J, Little S, Xia Q, Santiago-Walker A, Moy C, Hammond C, Lau Y, Sweiti H, Pant S. 603TiP Phase II, open-label study of erdafitinib in adult and adolescent patients (pts) with advanced solid tumours harboring fibroblast growth factor receptor (FGFR) gene alterations. Ann Oncol 2020. [DOI: 10.1016/j.annonc.2020.08.717] [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] Open
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48
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Alhalabi O, Hahn A, Msaouel P, Meric-Bernstam F, Naing A, Piha-Paul S, Janku F, Pant S, Yap T, Hong D, Fu S, Karp D, Campbell E, Campbell M, Shah A, Tannir N, Siefker-Radtke A, Gao J, Roszik J, Subbiah V. 779P Validation of prognostic scores in patients with metastatic bladder carcinoma (mBC) enrolled in early phase clinical trials. Ann Oncol 2020. [DOI: 10.1016/j.annonc.2020.08.851] [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: 10/23/2022] Open
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49
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Soubias O, Pant S, Heinrich F, Zhang Y, Roy NS, Li J, Jian X, Yohe ME, Randazzo PA, Lösche M, Tajkhorshid E, Byrd RA. Membrane surface recognition by the ASAP1 PH domain and consequences for interactions with the small GTPase Arf1. Sci Adv 2020; 6:6/40/eabd1882. [PMID: 32998886 PMCID: PMC7527224 DOI: 10.1126/sciadv.abd1882] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/05/2020] [Accepted: 08/04/2020] [Indexed: 05/05/2023]
Abstract
Adenosine diphosphate-ribosylation factor (Arf) guanosine triphosphatase-activating proteins (GAPs) are enzymes that need to bind to membranes to catalyze the hydrolysis of guanosine triphosphate (GTP) bound to the small GTP-binding protein Arf. Binding of the pleckstrin homology (PH) domain of the ArfGAP With SH3 domain, ankyrin repeat and PH domain 1 (ASAP1) to membranes containing phosphatidylinositol 4,5-bisphosphate [PI(4,5)P2] is key for maximum GTP hydrolysis but not fully understood. By combining nuclear magnetic resonance, neutron reflectometry, and molecular dynamics simulation, we show that binding of multiple PI(4,5)P2 molecules to the ASAP1 PH domain (i) triggers a functionally relevant allosteric conformational switch and (ii) maintains the PH domain in a well-defined orientation, allowing critical contacts with an Arf1 mimic to occur. Our model provides a framework to understand how binding of the ASAP1 PH domain to PI(4,5)P2 at the membrane may play a role in the regulation of ASAP1.
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Affiliation(s)
- Olivier Soubias
- Structural Biophysics Laboratory, Center for Cancer Research, National Cancer Institute, Frederick, MD 21702-1201, USA
| | - Shashank Pant
- NIH Center for Macromolecular Modeling and Bioinformatics, Beckman Institute for Advanced Science and Technology, Department of Biochemistry, Center for Biophysics and Quantitative Biology, University of Illinois at Urbana-Champaign, Urbana, IL 61801, USA
| | - Frank Heinrich
- Department of Physics, Carnegie Mellon University, Pittsburgh, PA 15213, USA
- NIST Center for Neutron Research, Gaithersburg, MD 20878, USA
| | - Yue Zhang
- Structural Biophysics Laboratory, Center for Cancer Research, National Cancer Institute, Frederick, MD 21702-1201, USA
| | - Neeladri Sekhar Roy
- Laboratory of Cellular and Molecular Biology, National Cancer Institute, National Institutes of Health, Bethesda, MD 20892, USA
| | - Jess Li
- Structural Biophysics Laboratory, Center for Cancer Research, National Cancer Institute, Frederick, MD 21702-1201, USA
| | - Xiaoying Jian
- Laboratory of Cellular and Molecular Biology, National Cancer Institute, National Institutes of Health, Bethesda, MD 20892, USA
| | - Marielle E Yohe
- Pediatric Oncology Branch, National Cancer Institute, National Institutes of Health, Bethesda, MD 20892, USA
| | - Paul A Randazzo
- Laboratory of Cellular and Molecular Biology, National Cancer Institute, National Institutes of Health, Bethesda, MD 20892, USA
| | - Mathias Lösche
- Department of Physics, Carnegie Mellon University, Pittsburgh, PA 15213, USA.
- NIST Center for Neutron Research, Gaithersburg, MD 20878, USA
- Department of Biomedical Engineering, Carnegie Mellon University, Pittsburgh, PA 15213, USA
| | - Emad Tajkhorshid
- NIH Center for Macromolecular Modeling and Bioinformatics, Beckman Institute for Advanced Science and Technology, Department of Biochemistry, Center for Biophysics and Quantitative Biology, University of Illinois at Urbana-Champaign, Urbana, IL 61801, USA.
| | - R Andrew Byrd
- Structural Biophysics Laboratory, Center for Cancer Research, National Cancer Institute, Frederick, MD 21702-1201, USA.
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Pant S, Yadav R, Misra S, Singh S, Singh R, Kumar S. P-297 Outcomes of combined modality treatment neoadjuvant chemo-radiotherapy and surgery in resectable esophageal carcinoma patients treated at a tertiary cancer care centre. Ann Oncol 2020. [DOI: 10.1016/j.annonc.2020.04.379] [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: 10/23/2022] Open
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