1
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Uenishi GI, Repic M, Yam JY, Landuyt A, Saikumar-Lakshmi P, Guo T, Zarin P, Sassone-Corsi M, Chicoine A, Kellogg H, Hunt M, Drow T, Tewari R, Cook PJ, Yang SJ, Cerosaletti K, Schweinoch D, Guiastrennec B, James E, Patel C, Chen TF, Buckner JH, Rawlings DJ, Wickham TJ, Mueller KT. GNTI-122: an autologous antigen-specific engineered Treg cell therapy for type 1 diabetes. JCI Insight 2024; 9:e171844. [PMID: 38516892 DOI: 10.1172/jci.insight.171844] [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] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/01/2023] [Accepted: 02/02/2024] [Indexed: 03/23/2024] Open
Abstract
Tregs have the potential to establish long-term immune tolerance in patients recently diagnosed with type 1 diabetes (T1D) by preserving β cell function. Adoptive transfer of autologous thymic Tregs, although safe, exhibited limited efficacy in previous T1D clinical trials, likely reflecting a lack of tissue specificity, limited IL-2 signaling support, and in vivo plasticity of Tregs. Here, we report a cell engineering strategy using bulk CD4+ T cells to generate a Treg cell therapy (GNTI-122) that stably expresses FOXP3, targets the pancreas and draining lymph nodes, and incorporates a chemically inducible signaling complex (CISC). GNTI-122 cells maintained an expression profile consistent with Treg phenotype and function. Activation of CISC using rapamycin mediated concentration-dependent STAT5 phosphorylation and, in concert with T cell receptor engagement, promoted cell proliferation. In response to the cognate antigen, GNTI-122 exhibited direct and bystander suppression of polyclonal, islet-specific effector T cells from patients with T1D. In an adoptive transfer mouse model of T1D, a mouse engineered-Treg analog of GNTI-122 trafficked to the pancreas, decreased the severity of insulitis, and prevented progression to diabetes. Taken together, these findings demonstrate in vitro and in vivo activity and support further development of GNTI-122 as a potential treatment for T1D.
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Affiliation(s)
| | | | | | | | | | - Tingxi Guo
- GentiBio Inc, Cambridge, Massachusetts, USA
| | | | | | | | | | - Martina Hunt
- Center for Immunity and Immunotherapies and the Program for Cell and Gene Therapy, Seattle Children's Research Institute, Seattle, Washington, USA
| | - Travis Drow
- Center for Immunity and Immunotherapies and the Program for Cell and Gene Therapy, Seattle Children's Research Institute, Seattle, Washington, USA
| | - Ritika Tewari
- Center for Translational Immunology, Benaroya Research Institute at Virginia Mason, Seattle, Washington, USA
| | - Peter J Cook
- Center for Immunity and Immunotherapies and the Program for Cell and Gene Therapy, Seattle Children's Research Institute, Seattle, Washington, USA
| | - Soo Jung Yang
- Center for Translational Immunology, Benaroya Research Institute at Virginia Mason, Seattle, Washington, USA
| | - Karen Cerosaletti
- Center for Translational Immunology, Benaroya Research Institute at Virginia Mason, Seattle, Washington, USA
| | | | | | - Eddie James
- Center for Translational Immunology, Benaroya Research Institute at Virginia Mason, Seattle, Washington, USA
| | | | | | - Jane H Buckner
- Center for Translational Immunology, Benaroya Research Institute at Virginia Mason, Seattle, Washington, USA
- Department of Medicine
- Department of Immunology, and
| | - David J Rawlings
- Center for Immunity and Immunotherapies and the Program for Cell and Gene Therapy, Seattle Children's Research Institute, Seattle, Washington, USA
- Department of Immunology, and
- Department of Pediatrics, University of Washington, Seattle, Washington, USA
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2
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Kodakandla G, West SJ, Wang Q, Tewari R, Zhu MX, Akimzhanov AM, Boehning D. Dynamic S-acylation of the ER-resident protein stromal interaction molecule 1 (STIM1) is required for store-operated Ca2+ entry. J Biol Chem 2022; 298:102303. [PMID: 35934052 PMCID: PMC9463532 DOI: 10.1016/j.jbc.2022.102303] [Citation(s) in RCA: 6] [Impact Index Per Article: 3.0] [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: 02/15/2022] [Revised: 07/15/2022] [Accepted: 07/18/2022] [Indexed: 02/07/2023] Open
Abstract
Many cell surface stimuli cause calcium release from endoplasmic reticulum (ER) stores to regulate cellular physiology. Upon ER calcium store depletion, the ER-resident protein stromal interaction molecule 1 (STIM1) physically interacts with plasma membrane protein Orai1 to induce calcium release–activated calcium (CRAC) currents that conduct calcium influx from the extracellular milieu. Although the physiological relevance of this process is well established, the mechanism supporting the assembly of these proteins is incompletely understood. Earlier we demonstrated a previously unknown post-translational modification of Orai1 with long-chain fatty acids, known as S-acylation. We found that S-acylation of Orai1 is dynamically regulated in a stimulus-dependent manner and essential for its function as a calcium channel. Here using the acyl resin–assisted capture assay, we show that STIM1 is also rapidly S-acylated at cysteine 437 upon ER calcium store depletion. Using a combination of live cell imaging and electrophysiology approaches with a mutant STIM1 protein, which could not be S-acylated, we determined that the S-acylation of STIM1 is required for the assembly of STIM1 into puncta with Orai1 and full CRAC channel function. Together with the S-acylation of Orai1, our data suggest that stimulus-dependent S-acylation of CRAC channel components Orai1 and STIM1 is a critical mechanism facilitating the CRAC channel assembly and function.
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Affiliation(s)
- Goutham Kodakandla
- Department of Biomedical Sciences, Cooper Medical School of Rowan University, Camden, New Jersey, USA
| | - Savannah J West
- Department of Biochemistry and Molecular Biology, McGovern Medical School, University of Texas Health Science Center at Houston, Houston, Texas, USA
| | - Qiaochu Wang
- Department of Integrative Biology and Pharmacology, McGovern Medical School, University of Texas Health Science Center at Houston, Houston, Texas, USA
| | - Ritika Tewari
- Department of Biochemistry and Molecular Biology, McGovern Medical School, University of Texas Health Science Center at Houston, Houston, Texas, USA
| | - Michael X Zhu
- Department of Integrative Biology and Pharmacology, McGovern Medical School, University of Texas Health Science Center at Houston, Houston, Texas, USA
| | - Askar M Akimzhanov
- Department of Biochemistry and Molecular Biology, McGovern Medical School, University of Texas Health Science Center at Houston, Houston, Texas, USA.
| | - Darren Boehning
- Department of Biomedical Sciences, Cooper Medical School of Rowan University, Camden, New Jersey, USA.
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3
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Kodakandla G, West S, Wang Q, Tewari R, Zhu M, Akimzhanov A, Boehning DF. S‐acylation of STIM1 regulates store‐operated calcium entry. FASEB J 2022. [DOI: 10.1096/fasebj.2022.36.s1.r3741] [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)
| | - Savannah West
- University of Texas Health Science Center at HoustonHoustonTX
| | - Qioachu Wang
- University of Texas Health Science Center at HoustonHoustonTX
| | - Ritika Tewari
- University of Texas Health Science Center at HoustonHoustonTX
| | - Michael Zhu
- University of Texas Health Science Center at HoustonHoustonTX
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4
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Devi A, Neogy S, Sharma S, Menon R, Tewari R. Characterization of argon ion irradiation induced changes in microstructure and mechanical property of binary Zr−2.9 wt% Sn alloy. Radiat Phys Chem Oxf Engl 1993 2022. [DOI: 10.1016/j.radphyschem.2021.109802] [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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5
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West SJ, Kodakandla G, Wang Q, Tewari R, Zhu MX, Boehning D, Akimzhanov AM. S-acylation of Orai1 regulates store-operated Ca2+ entry. J Cell Sci 2021; 135:269207. [PMID: 34156466 DOI: 10.1242/jcs.258579] [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: 02/25/2021] [Accepted: 05/21/2021] [Indexed: 12/12/2022] Open
Abstract
Store-operated Ca2+ entry is a central component of intracellular Ca2+ signaling pathways. The Ca2+ release-activated channel (CRAC) mediates store-operated Ca2+ entry in many different cell types. The CRAC channel is composed of the plasma membrane (PM)-localized Orai1 channel and endoplasmic reticulum (ER)-localized STIM1 Ca2+ sensor. Upon ER Ca2+ store depletion, Orai1 and STIM1 form complexes at ER-PM junctions, leading to the formation of activated CRAC channels. Although the importance of CRAC channels is well described, the underlying mechanisms that regulate the recruitment of Orai1 to ER-PM junctions are not fully understood. Here, we describe the rapid and transient S-acylation of Orai1. Using biochemical approaches, we show that Orai1 is rapidly S-acylated at cysteine 143 upon ER Ca2+ store depletion. Importantly, S-acylation of cysteine 143 is required for Orai1-mediated Ca2+ entry and recruitment to STIM1 puncta. We conclude that store depletion-induced S-acylation of Orai1 is necessary for recruitment to ER-PM junctions, subsequent binding to STIM1 and channel activation.
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Affiliation(s)
- Savannah J West
- Department of Biochemistry and Molecular Biology, McGovern Medical School, University of Texas Health Science Center at Houston, Houston, TX 77030, USA
| | - Goutham Kodakandla
- Department of Biomedical Sciences, Cooper Medical School of Rowan University, Camden, NJ 08103, USA
| | - Qioachu Wang
- Department of Integrative Biology and Pharmacology, McGovern Medical School, University of Texas Health Science Center at Houston, Houston, TX 77030, USA
| | - Ritika Tewari
- Department of Biochemistry and Molecular Biology, McGovern Medical School, University of Texas Health Science Center at Houston, Houston, TX 77030, USA
| | - Michael X Zhu
- Department of Integrative Biology and Pharmacology, McGovern Medical School, University of Texas Health Science Center at Houston, Houston, TX 77030, USA
| | - Darren Boehning
- Department of Biomedical Sciences, Cooper Medical School of Rowan University, Camden, NJ 08103, USA
| | - Askar M Akimzhanov
- Department of Biochemistry and Molecular Biology, McGovern Medical School, University of Texas Health Science Center at Houston, Houston, TX 77030, USA
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6
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Bieerkehazhi S, Fan Y, West SJ, Tewari R, Ko J, Mills T, Boehning D, Akimzhanov AM. Ca2+-dependent protein acyltransferase DHHC21 controls activation of CD4+ T cells. J Cell Sci 2021; 135:268992. [PMID: 34080635 DOI: 10.1242/jcs.258186] [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] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/10/2020] [Accepted: 04/13/2021] [Indexed: 11/20/2022] Open
Abstract
Despite the recognized significance of reversible protein lipidation (S-acylation) for T cell receptor signal transduction, the enzymatic control of this post-translational modification in T cells remains poorly understood. Here, we demonstrate that DHHC21 (also known as ZDHHC21), a member of the DHHC family of mammalian protein acyltransferases, mediates T cell receptor-induced S-acylation of proximal T cell signaling proteins. Using Zdhhc21dep mice, which express a functionally deficient version of DHHC21, we show that DHHC21 is a Ca2+/calmodulin-dependent enzyme critical for activation of naïve CD4+ T cells in response to T cell receptor stimulation. We find that disruption of the Ca2+/calmodulin-binding domain of DHHC21 does not affect thymic T cell development but prevents differentiation of peripheral CD4+ T cells into Th1, Th2 and Th17 effector T helper lineages. Our findings identify DHHC21 as an essential component of the T cell receptor signaling machinery and define a new role for protein acyltransferases in regulation of T cell-mediated immunity.
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Affiliation(s)
- Shayahati Bieerkehazhi
- Department of Biochemistry and Molecular Biology, McGovern Medical School, University of Texas Health Science Center at Houston, Houston, TX 77030, USA
| | - Ying Fan
- Department of Biochemistry and Molecular Biology, McGovern Medical School, University of Texas Health Science Center at Houston, Houston, TX 77030, USA.,Cooper Medical School of Rowan University, Camden, NJ 08103, USA
| | - Savannah J West
- Department of Biochemistry and Molecular Biology, McGovern Medical School, University of Texas Health Science Center at Houston, Houston, TX 77030, USA.,MD Anderson Cancer Center and University of Texas Health Science at Houston Graduate School, Houston, TX 77030, USA
| | - Ritika Tewari
- Department of Biochemistry and Molecular Biology, McGovern Medical School, University of Texas Health Science Center at Houston, Houston, TX 77030, USA
| | - Junsuk Ko
- Department of Biochemistry and Molecular Biology, McGovern Medical School, University of Texas Health Science Center at Houston, Houston, TX 77030, USA.,MD Anderson Cancer Center and University of Texas Health Science at Houston Graduate School, Houston, TX 77030, USA
| | - Tingting Mills
- Department of Biochemistry and Molecular Biology, McGovern Medical School, University of Texas Health Science Center at Houston, Houston, TX 77030, USA
| | - Darren Boehning
- Cooper Medical School of Rowan University, Camden, NJ 08103, USA
| | - Askar M Akimzhanov
- Department of Biochemistry and Molecular Biology, McGovern Medical School, University of Texas Health Science Center at Houston, Houston, TX 77030, USA
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7
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Dalvi AA, Remya Devi P, Singh V, Tewari R, Verma R, Swain KK. Characterization of siliceous cake for the beneficiation of 231Pa. Progress in Nuclear Energy 2021. [DOI: 10.1016/j.pnucene.2021.103675] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 10/22/2022]
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8
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Tewari R, Shayahati B, Fan Y, Akimzhanov AM. T cell receptor-dependent S-acylation of ZAP-70 controls activation of T cells. J Biol Chem 2021; 296:100311. [PMID: 33482200 PMCID: PMC7949058 DOI: 10.1016/j.jbc.2021.100311] [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] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/21/2020] [Revised: 12/21/2020] [Accepted: 01/14/2021] [Indexed: 02/06/2023] Open
Abstract
ZAP-70 is a tyrosine kinase essential for T cell immune responses. Upon engagement of the T cell receptor (TCR), ZAP-70 is recruited to the specialized plasma membrane domains, becomes activated, and is released to phosphorylate its laterally segregated targets. A shift in ZAP-70 distribution at the plasma membrane is recognized as a critical step in TCR signal transduction and amplification. However, the molecular mechanism supporting stimulation-dependent plasma membrane compartmentalization of ZAP-70 remains poorly understood. In this study, we identified previously uncharacterized lipidation (S-acylation) of ZAP-70 using Acyl-Biotin Exchange assay, a technique that selectively captures S-acylated proteins. We found that this posttranslational modification of ZAP-70 is dispensable for its enzymatic activity. However, the lipidation-deficient mutant of ZAP-70 failed to propagate the TCR pathway suggesting that S-acylation is essential for ZAP-70 interaction with its protein substrates. The kinetics of ZAP-70 S-acylation were consistent with TCR signaling events indicating that agonist-induced S-acylation is a part of the signaling mechanism controlling T cell activation and function. Taken together, our results suggest that TCR-induced S-acylation of ZAP-70 can serve as a critical regulator of T cell-mediated immunity.
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Affiliation(s)
- Ritika Tewari
- Department of Biochemistry and Molecular Biology, McGovern Medical School, University of Texas Health Science Center at Houston, Houston, USA
| | - Bieerkehazhi Shayahati
- Department of Biochemistry and Molecular Biology, McGovern Medical School, University of Texas Health Science Center at Houston, Houston, USA
| | - Ying Fan
- Department of Biochemistry and Molecular Biology, McGovern Medical School, University of Texas Health Science Center at Houston, Houston, USA; Department of Biomedical Sciences, Cooper Medical School of Rowan University, Camden, USA
| | - Askar M Akimzhanov
- Department of Biochemistry and Molecular Biology, McGovern Medical School, University of Texas Health Science Center at Houston, Houston, USA.
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9
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Majumdar S, Kishor J, Behera AN, Vishwanadh B, Borgohain A, Kapoor R, Tewari R, Kain V, Krishnan M, Dey GK, Banerjee S. Preparation and Characterization of Nb-1Zr-0.1C Alloy Suitable for Liquid Metal Coolant Channels of High Temperature Reactors. Journal of Nuclear Engineering and Radiation Science 2021. [DOI: 10.1115/1.4047919] [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: 11/08/2022]
Abstract
Abstract
A novel process comprising of aluminothermic coreduction of mixed oxides followed by arc and electron beam melt refining was developed for preparation of Nb-1Zr-0.1C alloy. The parameters of the process were optimized by considering the thermodynamic (heat) and mass balance phenomenon. The ingots of the homogenized alloy produced after electron beam melt consolidation were further extruded into tubes. The alloy was vacuum annealed at 1350–1800 °C to study the stability of Nb2C and Nb(Zr)C carbide precipitates in the microstructure. Compression creep tests conducted at 900 and 1000 °C revealed a stress exponent value of 2 and activation energy of 508 kJ/mol. NbSi2-based coatings were developed on the Nb-1Zr-0.1C alloy tubes using pack siliconizing process. The coated alloy was tested for oxidation at 1250 °C, and corrosion in liquid lead-bismuth eutectic (LBE) alloy at 875 °C for prolonged duration. The silicide-coated alloy showed superior oxidation and LBE corrosion resistance at high temperatures. The alloy was found to be a promising material for coolant channels of high temperature reactors.
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Affiliation(s)
- S. Majumdar
- Materials Group, Bhabha Atomic Research Centre, Trombay, Mumbai 400085, India
| | - J. Kishor
- Materials Group, Bhabha Atomic Research Centre, Trombay, Mumbai 400085, India
| | - A. N. Behera
- Materials Group, Bhabha Atomic Research Centre, Trombay, Mumbai 400085, India
| | - B. Vishwanadh
- Materials Group, Bhabha Atomic Research Centre, Trombay, Mumbai 400085, India
| | - A. Borgohain
- Reactor Engineering Division, Bhabha Atomic Research Centre, Trombay, Mumbai 400085, India
| | - R. Kapoor
- Materials Group, Bhabha Atomic Research Centre, Trombay, Mumbai 400085, India
| | - R. Tewari
- Materials Group, Bhabha Atomic Research Centre, Trombay, Mumbai 400085, India
| | - V. Kain
- Materials Group, Bhabha Atomic Research Centre, Trombay, Mumbai 400085, India
| | - Madangopal Krishnan
- Materials Group, Bhabha Atomic Research Centre, Trombay, Mumbai 400085, India
| | - G. K. Dey
- Homi Bhabha National Institute, Mumbai 400094, India
| | - S. Banerjee
- Homi Bhabha National Institute, Mumbai 400094, India
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10
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Gireud-Goss M, Reyes S, Tewari R, Patrizz A, Howe MD, Kofler J, Waxham MN, McCullough LD, Bean AJ. The ubiquitin ligase UBE4B regulates amyloid precursor protein ubiquitination, endosomal trafficking, and amyloid β42 generation and secretion. Mol Cell Neurosci 2020; 108:103542. [PMID: 32841720 DOI: 10.1016/j.mcn.2020.103542] [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] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/25/2020] [Revised: 08/18/2020] [Accepted: 08/20/2020] [Indexed: 01/01/2023] Open
Abstract
The extracellular accumulation of amyloid β (Aβ) fragments of amyloid precursor protein (APP) in brain parenchyma is a pathological hallmark of Alzheimer's disease (AD). APP can be cleaved into Aβ on late endosomes/multivesicular bodies (MVBs). E3 ubiquitin ligases have been linked to Aβ production, but specific E3 ligases associated with APP ubiquitination that may affect targeting of APP to endosomes have not yet been described. Using cultured cortical neurons isolated from rat pups, we reconstituted APP movement into the internal vesicles (ILVs) of MVBs. Loss of endosomal sorting complexes required for transport (ESCRT) components inhibited APP movement into ILVs and increased endosomal Aβ42 generation, implying a requirement for APP ubiquitination. We identified an ESCRT-binding and APP-interacting endosomal E3 ubiquitin ligase, ubiquitination factor E4B (UBE4B) that regulates APP ubiquitination. Depleting UBE4B in neurons inhibited APP ubiquitination and internalization into MVBs, resulting in increased endosomal Aβ42 levels and increased neuronal secretion of Aβ42. When we examined AD brains, we found levels of the UBE4B-interacting ESCRT component, hepatocyte growth factor-regulated tyrosine kinase substrate (Hrs), were significantly decreased in AD brains. These data suggest that ESCRT components critical for membrane protein sorting in the endocytic pathway are altered in AD. These results indicate that the molecular machinery underlying endosomal trafficking of APP, including the ubiquitin ligase UBE4B, regulates Aβ levels and may play an essential role in AD progression.
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Affiliation(s)
- Monica Gireud-Goss
- Department of Neurobiology and Anatomy, McGovern Medical School at The University of Texas Health Science Center at Houston, United States of America; The M.D. Anderson/UTHealth Graduate School of Biomedical Sciences at Houston, United States of America; Department of Neurology McGovern Medical School at The University of Texas Health Science Center at Houston, United States of America
| | - Sahily Reyes
- Department of Neurobiology and Anatomy, McGovern Medical School at The University of Texas Health Science Center at Houston, United States of America; The M.D. Anderson/UTHealth Graduate School of Biomedical Sciences at Houston, United States of America
| | - Ritika Tewari
- Department of Neurobiology and Anatomy, McGovern Medical School at The University of Texas Health Science Center at Houston, United States of America
| | - Anthony Patrizz
- The M.D. Anderson/UTHealth Graduate School of Biomedical Sciences at Houston, United States of America; Department of Neurology McGovern Medical School at The University of Texas Health Science Center at Houston, United States of America
| | - Matthew D Howe
- The M.D. Anderson/UTHealth Graduate School of Biomedical Sciences at Houston, United States of America; Department of Neurology McGovern Medical School at The University of Texas Health Science Center at Houston, United States of America
| | - Julia Kofler
- Division of Neuropathology, University of Pittsburgh, School of Medicine, Pittsburgh, PA 15261, United States of America
| | - M Neal Waxham
- Department of Neurobiology and Anatomy, McGovern Medical School at The University of Texas Health Science Center at Houston, United States of America
| | - Louise D McCullough
- The M.D. Anderson/UTHealth Graduate School of Biomedical Sciences at Houston, United States of America; Department of Neurology McGovern Medical School at The University of Texas Health Science Center at Houston, United States of America
| | - Andrew J Bean
- Department of Neurobiology and Anatomy, McGovern Medical School at The University of Texas Health Science Center at Houston, United States of America; The M.D. Anderson/UTHealth Graduate School of Biomedical Sciences at Houston, United States of America; Department of Pediatrics, The University of Texas M.D. Anderson Cancer Center, Houston, TX 77030, United States of America; Rush University Graduate College, Chicago, IL 60612, United States of America.
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11
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Fan Y, Shayahati B, Tewari R, Boehning D, Akimzhanov AM. Regulation of T cell receptor signaling by protein acyltransferase DHHC21. Mol Biol Rep 2020; 47:6471-6478. [PMID: 32789573 DOI: 10.1007/s11033-020-05691-1] [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] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/22/2020] [Accepted: 07/26/2020] [Indexed: 12/11/2022]
Abstract
S-acylation reversible-post-translational lipidation of cysteine residues-is emerging as an important regulatory mechanism in T cell signaling. Dynamic S-acylation is critical for protein recruitment into the T cell receptor complex and initiation of the subsequent signaling cascade. However, the enzymatic control of protein S-acylation in T cells remains poorly understood. Here, we report a previously uncharacterized role of DHHC21, a member of the mammalian family of DHHC protein acyltransferases, in regulation of the T cell receptor pathway. We found that loss of DHHC21 prevented S-acylation of key T cell signaling proteins, resulting in disruption of the early signaling events and suppressed expression of T cell activation markers. Furthermore, downregulation of DHHC21 prevented activation and differentiation of naïve T cells into effector subtypes. Together, our study provides the first direct evidence that DHHC protein acyltransferases can play an essential role in regulation of T cell-mediated immunity.
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Affiliation(s)
- Ying Fan
- Department of Biochemistry and Molecular Biology, University of Texas-McGovern Medical School, 6431 Fannin Street, Suite 6.200, Houston, TX, 77030, USA
- Cooper Medical School of Rowan University, 401 Broadway, Camden, NJ, 08103, USA
| | - Bieerkehazhi Shayahati
- Department of Biochemistry and Molecular Biology, University of Texas-McGovern Medical School, 6431 Fannin Street, Suite 6.200, Houston, TX, 77030, USA
| | - Ritika Tewari
- Department of Biochemistry and Molecular Biology, University of Texas-McGovern Medical School, 6431 Fannin Street, Suite 6.200, Houston, TX, 77030, USA
| | - Darren Boehning
- Cooper Medical School of Rowan University, 401 Broadway, Camden, NJ, 08103, USA
| | - Askar M Akimzhanov
- Department of Biochemistry and Molecular Biology, University of Texas-McGovern Medical School, 6431 Fannin Street, Suite 6.200, Houston, TX, 77030, USA.
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12
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Agarwal M, Tewari R, Shijith K, Guleria P, Tathagata C. Congenital infantile myofibroma; case report and review of literature. Human Pathology: Case Reports 2020. [DOI: 10.1016/j.ehpc.2020.200363] [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: 11/25/2022] Open
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13
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Abstract
Protein S-acylation, also referred to as S-palmitoylation, is a reversible post-translational modification of cysteine residues with long-chain fatty acids via a labile thioester bond. S-acylation, which is emerging as a widespread regulatory mechanism, can modulate almost all aspects of the biological activity of proteins, from complex formation to protein trafficking and protein stability. The recent progress in understanding of the biological function of protein S-acylation was achieved largely due to the development of novel biochemical tools allowing robust and sensitive detection of protein S-acylation in a variety of biological samples. Here, we describe acyl resin-assisted capture (Acyl-RAC), a recently developed method based on selective capture of endogenously S-acylated proteins by thiol-reactive Sepharose beads. Compared to existing approaches, Acyl-RAC requires fewer steps and can yield more reliable results when coupled with mass spectrometry for identification of novel S-acylation targets. A major limitation in this technique is the lack of ability to discriminate between fatty acid species attached to cysteines via the same thioester bond.
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Affiliation(s)
- Ritika Tewari
- Department of Biochemistry and Molecular Biology, McGovern Medical School at UT Health
| | - Savannah J West
- Department of Biochemistry and Molecular Biology, McGovern Medical School at UT Health; MD Anderson UT Health Graduate School
| | - Bieerkehazi Shayahati
- Department of Biochemistry and Molecular Biology, McGovern Medical School at UT Health
| | - Askar M Akimzhanov
- Department of Biochemistry and Molecular Biology, McGovern Medical School at UT Health;
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14
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15
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Sharma G, Tewari R, Dhatwalia SK, Yadav R, Behera D, Sethi S. A loop-mediated isothermal amplification assay for the diagnosis of pulmonary tuberculosis. Lett Appl Microbiol 2019; 68:219-225. [PMID: 30636048 DOI: 10.1111/lam.13115] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.4] [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: 06/22/2018] [Revised: 09/08/2018] [Accepted: 10/08/2018] [Indexed: 11/28/2022]
Abstract
Quantitated Mycobacterium tuberculosis (M.tb) H37Rv DNA was used to analyse the sensitivity and the specificity was assessed using DNA isolated from the reference strain H37Rv, 12 nontuberculous mycobacterium (NTM) species and five nonmycobacterium species. Furthermore, performance of the assay was evaluated on the sputum samples and compared with smear microscopy, culture and PCR. mpt64 (also called mpb64 or Rv1980c) loop-mediated isothermal amplification (LAMP) successfully detected 1 pg DNA within 40 min and successfully rejected NTMs and other bacterial species tested. It specifically detected all the 119 confirmed TB cases and 100 of the 104 control cases. The resulting sensitivity and specificity of LAMP assay was found to be 100% (95% CI: 96·79-100%) and 96·15% (95% CI; 90·44-98·94%) respectively. SIGNIFICANCE AND IMPACT OF THE STUDY: Loop-mediated isothermal amplification (LAMP) is a technique for isothermal DNA amplification suitable for cost-limited settings as it prevents the use of sophisticated instruments. Using mpt64 antigenic protein gene, we developed a LAMP assay especially for organisms of the M. tuberculosis complex. mpt64 LAMP assay showed 100% sensitivity and detected all the bacteriologically and clinically positive TB cases not detected by smear, culture or PCR methods.
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Affiliation(s)
- G Sharma
- Department of Microbial Biotechnology, Panjab University, Chandigarh, India
| | - R Tewari
- Department of Microbial Biotechnology, Panjab University, Chandigarh, India
| | - S K Dhatwalia
- Department of Biophysics, Panjab University, Chandigarh, India
| | - R Yadav
- Department of Medical Microbiology, Postgraduate Institute of Medical Education and Research, Chandigarh, India
| | - D Behera
- Department of Pulmonary Medicine, Postgraduate Institute of Medical Education and Research, Chandigarh, India
| | - S Sethi
- Department of Medical Microbiology, Postgraduate Institute of Medical Education and Research, Chandigarh, India
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Sharma KS, Ningthoujam RS, Dubey AK, Chattopadhyay A, Phapale S, Juluri RR, Mukherjee S, Tewari R, Shetake NG, Pandey BN, Vatsa RK. Synthesis and characterization of monodispersed water dispersible Fe 3O 4 nanoparticles and in vitro studies on human breast carcinoma cell line under hyperthermia condition. Sci Rep 2018; 8:14766. [PMID: 30283083 PMCID: PMC6170485 DOI: 10.1038/s41598-018-32934-w] [Citation(s) in RCA: 41] [Impact Index Per Article: 6.8] [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: 01/12/2016] [Accepted: 08/30/2018] [Indexed: 11/21/2022] Open
Abstract
Monodispersed Fe3O4 magnetic nanoparticles (MNPs) having size of 7 nm have been prepared from iron oleate and made water dispersible by functionalization for biomedical applications. Three different reactions employing thioglycolic acid, aspartic acid and aminophosphonate were performed on oleic acid coated Fe3O4. In order to achieve a control on particle size, the pristine nanoparticles were heated in presence of ferric oleate which led to increase in size from 7 to 11 nm. Reaction parameters such as rate of heating, reaction temperature and duration of heating have been studied. Shape of particles was found to change from spherical to cuboid. The cuboid shape in turn enhances magneto-crystalline anisotropy (Ku). Heating efficacy of these nanoparticles for hyperthermia was also evaluated for different shapes and sizes. We demonstrate heat generation from these MNPs for hyperthermia application under alternating current (AC) magnetic field and optimized heating efficiency by controlling morphology of particles. We have also studied intra-cellular uptake and localization of nanoparticles and cytotoxicity under AC magnetic field in human breast carcinoma cell line.
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Affiliation(s)
- K S Sharma
- Chemistry Division, Bhabha Atomic Research Centre, Mumbai, 400085, India
| | - R S Ningthoujam
- Chemistry Division, Bhabha Atomic Research Centre, Mumbai, 400085, India.
| | - A K Dubey
- Bio-organic Division, Bhabha Atomic Research Centre, Mumbai, 400085, India
| | - A Chattopadhyay
- Bio-organic Division, Bhabha Atomic Research Centre, Mumbai, 400085, India
| | - S Phapale
- Chemistry Division, Bhabha Atomic Research Centre, Mumbai, 400085, India
| | - R R Juluri
- Institute of Physics, SachivalayaMarg, Bhubaneswar, 751005, India
| | - S Mukherjee
- UGC-DAE Consortium for Scientific Research, Mumbai Centre, Mumbai, 400085, India
| | - R Tewari
- Material Science Division, Bhabha Atomic Research Centre, Mumbai, 400085, India
| | - Neena G Shetake
- Radiation Biology and Health Sciences Division, Bhabha Atomic Research Centre, Mumbai, 400085, India
| | - B N Pandey
- Radiation Biology and Health Sciences Division, Bhabha Atomic Research Centre, Mumbai, 400085, India
| | - R K Vatsa
- Chemistry Division, Bhabha Atomic Research Centre, Mumbai, 400085, India
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17
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Sharma A, Singh S, Tewari R, Bhatt V, Sharma J, Maurya I. Phytochemical analysis and mode of action against Candida glabrata of Paeonia emodi extracts. J Mycol Med 2018; 28:443-451. [DOI: 10.1016/j.mycmed.2018.04.008] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/17/2018] [Revised: 04/22/2018] [Accepted: 04/27/2018] [Indexed: 01/26/2023]
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18
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Rajak S, Ghosh S, Varshney J, Srivastava A, Tewari R, Kain V. Electrochemical investigation of uranyl species reduction in alkaline oxalate electrolyte and microstructural characterization of deposited nanocrystalline UO2 thin films. J Electroanal Chem (Lausanne) 2018. [DOI: 10.1016/j.jelechem.2018.01.060] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
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Rani P, Kumar A, Vishwanadh B, Ali K, Arya A, Tewari R, Subramaniam A. Liquid like nucleation in free-standing nanoscale films. Nanoscale 2017; 9:12283-12287. [PMID: 28703820 DOI: 10.1039/c7nr03225k] [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] [Subscribe] [Scholar Register] [Indexed: 06/07/2023]
Abstract
The concept of a critical nucleus size (r*) is of pivotal importance in phase transformations involving nucleation and growth. The current investigation pertains to crystallization in nanoscale thin films and study of the same using high resolution lattice fringe imaging (HRLFI) and finite element simulations. Using the CuZrAl bulk metallic glass system as a model system for this study, we demonstrate a liquid like nucleation behaviour in nanoscale free-standing films upon heating. The r* for the formation of the Cu10Zr7 phase in thin films (of decreasing thickness) approaches that of the r* for the formation of the crystal from a liquid (i.e.). Working in the nucleation dominant regime, we introduce the concept of 'depth sensitive lattice fringe imaging'. The thickness of the film is determined by electron energy loss spectroscopy and the strain energy of the system is computed using finite element computations.
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Affiliation(s)
- Pooja Rani
- Materials Science and Engineering, Indian Institute of Technology Kanpur, Kanpur-208016, India.
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Abstract
Warfarin is an oral anticoagulant used extensively in clinical practice; However, its side-effect of causing renal damage has been recently detected. The mechanism leading to renal damage is glomerular hemorrhage and red blood cell tubular casts prothrombin time. Recently, it was found that warfarin causes renal damage in patients with chronic kidney disease and is also associated with progression of renal disease. Warfarin causing acute kidney injury in patients with normal renal function is a rare manifestation. It is important to be aware of this condition as its innocuous presence can lead to chronic kidney disease if not corrected in time. Further studies have also found that novel oral anticoagulants such as dabigatran also cause a similar syndrome and hence a new term called anticoagulant-related nephropathy is now in vogue.
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Affiliation(s)
- S Mendonca
- Department of Medicine, Armed Forces Medical College and Command Hospital, Pune, Maharashtra, India
| | - D Gupta
- Department of Pathology and Laboratory Science and Armed Forces Medical College and Command Hospital, Pune, Maharashtra, India
| | - A Valsan
- Department of Medicine, Armed Forces Medical College and Command Hospital, Pune, Maharashtra, India
| | - R Tewari
- Department of Medicine, Armed Forces Medical College and Command Hospital, Pune, Maharashtra, India
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Borgohain A, Srivastava A, Jana S, Maheshwari N, Kulkarni R, Vijayan P, Tewari R, Ram AM, Jha S. Natural circulation studies in a LBE loop for a wide range of temperature. Nuclear Engineering and Design 2016. [DOI: 10.1016/j.nucengdes.2016.01.029] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 10/22/2022]
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Tyagi M, Vishwanadh B, Bhattacharyya K, Ghosh SK, Tewari R. A study on reaction kinetics and development of silicide coatings on Nb–1Zr–0.1C alloy by molten salt technique. RSC Adv 2016. [DOI: 10.1039/c6ra08280g] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022] Open
Abstract
In this study a molten salt technique has been used to produce silicide coating on Nb–1Zr–0.1C alloy using a NaCl–KCl–NaF–Na2SiF6–Si melt.
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Affiliation(s)
- M. Tyagi
- Homi Bhabha National Institute
- Mumbai 400094
- India
| | - B. Vishwanadh
- Materials Science Division
- Bhabha Atomic Research Centre
- Mumbai 400085
- India
| | - K. Bhattacharyya
- Chemistry Division
- Bhabha Atomic Research Centre
- Mumbai 400085
- India
| | - S. K. Ghosh
- Homi Bhabha National Institute
- Mumbai 400094
- India
- Materials Processing Division
- Bhabha Atomic Research Centre
| | - R. Tewari
- Homi Bhabha National Institute
- Mumbai 400094
- India
- Materials Science Division
- Bhabha Atomic Research Centre
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Varshney J, Rajak S, Ghosh SK, Vishwanadh B, Tewari R, Sastry PU, Kain V, Dey GK. Electrosynthesis and characterization of nanocrystalline UO2 coating from aqueous alkaline electrolyte. RSC Adv 2016. [DOI: 10.1039/c6ra24658c] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022] Open
Abstract
In this study, UO2 coating was deposited by direct current (DC) electrolysis from an aqueous electrolyte containing UO2(NO3)2 as source of uranium.
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Affiliation(s)
- J. Varshney
- Materials Processing and Corrosion Engineering Division
- Bhabha Atomic Research Centre
- Mumbai-400 085
- India
| | - S. Rajak
- Materials Processing and Corrosion Engineering Division
- Bhabha Atomic Research Centre
- Mumbai-400 085
- India
| | - S. K. Ghosh
- Materials Processing and Corrosion Engineering Division
- Bhabha Atomic Research Centre
- Mumbai-400 085
- India
| | - B. Vishwanadh
- Materials Science Division
- Bhabha Atomic Research Centre
- Mumbai-400 085
- India
| | - R. Tewari
- Materials Science Division
- Bhabha Atomic Research Centre
- Mumbai-400 085
- India
| | - P. U. Sastry
- Solid State Physics Division
- Bhabha Atomic Research Centre
- Mumbai-400 085
- India
| | - V. Kain
- Materials Processing and Corrosion Engineering Division
- Bhabha Atomic Research Centre
- Mumbai-400 085
- India
| | - G. K. Dey
- Materials Science Division
- Bhabha Atomic Research Centre
- Mumbai-400 085
- India
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Gowda KK, Nada R, Ramachandran R, Joshi K, Tewari R, Kohli HS, Jha V, Gupta KL. Proliferative glomerulonephritis with monoclonal immunoglobulin deposition disease: The utility of routine staining with immunoglobulin light chains. Indian J Nephrol 2015; 25:344-8. [PMID: 26664209 PMCID: PMC4663771 DOI: 10.4103/0971-4065.151354] [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] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/04/2022] Open
Abstract
Proliferative glomerulonephritis occurring as a consequence of monoclonal glomerular deposits of IgG is uncommon. It is a form of renal involvement in monoclonal gammopathy that mimics immune complex glomerulonephritis. Here, we report the first series of proliferative glomerulonephritis with monoclonal IgG deposits (PGNMID) from the Indian subcontinent highlighting use of light chain immunofluorescence (IF) in routine renal biopsy interpretation. We retrieved 6 patients diagnosed as proliferative glomerulonephritis with monoclonal IgG deposits (PGNMID) out of 160 biopsies (3.7%) with membranoproliferative patterns over 5 1/2 years (2009-2014), one of whom had recurrence 6 months post-renal transplant. Four (67%) patients presented with rapidly progressive renal failure and two (33%) with nephrotic syndrome. None of these patients had overt multiple myeloma. The predominant histologic pattern was membranoproliferative with all the biopsies showing IgG3 Kappa deposits on IF. The deposits were primarily subendothelial on electron microscopy.
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Affiliation(s)
- K K Gowda
- Department of Histopathology, PGIMER, Chandigarh, India
| | - R Nada
- Department of Histopathology, PGIMER, Chandigarh, India
| | | | - K Joshi
- Department of Histopathology, PGIMER, Chandigarh, India
| | - R Tewari
- Department of Histopathology, PGIMER, Chandigarh, India
| | - H S Kohli
- Department of Nephrology, PGIMER, Chandigarh, India
| | - V Jha
- Department of Nephrology, PGIMER, Chandigarh, India
| | - K L Gupta
- Department of Nephrology, PGIMER, Chandigarh, India
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Tewari R, Bachert C, Linstedt AD. Induced oligomerization targets Golgi proteins for degradation in lysosomes. Mol Biol Cell 2015; 26:4427-37. [PMID: 26446839 PMCID: PMC4666137 DOI: 10.1091/mbc.e15-04-0207] [Citation(s) in RCA: 20] [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] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/13/2015] [Accepted: 09/29/2015] [Indexed: 01/07/2023] Open
Abstract
Oligomerization or homotypic clustering diverts Golgi membrane proteins into the canonical GGA1/clathrin-dependent Golgi-to-lysosome pathway revealing the presence of cellular quality control that could be useful for therapies designed to down-regulate specific proteins in the secretory pathway. Manganese protects cells against forms of Shiga toxin by down-regulating the cycling Golgi protein GPP130. Down-regulation occurs when Mn binding causes GPP130 to oligomerize and traffic to lysosomes. To determine how GPP130 is redirected to lysosomes, we tested the role of GGA1 and clathrin, which mediate sorting in the canonical Golgi-to-lysosome pathway. GPP130 oligomerization was induced using either Mn or a self-interacting version of the FKBP domain. Inhibition of GGA1 or clathrin specifically blocked GPP130 redistribution, suggesting recognition of the aggregated GPP130 by the GGA1/clathrin-sorting complex. Unexpectedly, however, GPP130’s cytoplasmic domain was not required, and redistribution also occurred after removal of GPP130 sequences needed for its normal cycling. Therefore, to test whether aggregate recognition might be a general phenomenon rather than one involving a specific GPP130 determinant, we induced homo-oligomerization of two unrelated Golgi-targeted constructs using the FKBP strategy. These were targeted to the cis- and trans-Golgi, respectively, using domains from mannosidase-1 and galactosyltransferase. Significantly, upon oligomerization, each redistributed to peripheral punctae and was degraded. This occurred in the absence of detectable UPR activation. These findings suggest the unexpected presence of quality control in the Golgi that recognizes aggregated Golgi proteins and targets them for degradation in lysosomes.
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Affiliation(s)
- Ritika Tewari
- Department of Biological Sciences, Carnegie Mellon University, Pittsburgh, PA 15213
| | - Collin Bachert
- Department of Biological Sciences, Carnegie Mellon University, Pittsburgh, PA 15213
| | - Adam D Linstedt
- Department of Biological Sciences, Carnegie Mellon University, Pittsburgh, PA 15213
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Abstract
Defects responsible for intense blue emission in CaZrO3 are investigated using PL and EPR spectroscopy and complimented by DFT calculations.
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Affiliation(s)
- Santosh K. Gupta
- Radiochemistry Division
- Bhabha Atomic Research Centre
- Mumbai-400085
- India
| | - P. S. Ghosh
- Materials Science Division
- Bhabha Atomic Research Centre
- Mumbai-400085
- India
| | - N. Pathak
- Radiochemistry Division
- Bhabha Atomic Research Centre
- Mumbai-400085
- India
| | - R. Tewari
- Materials Science Division
- Bhabha Atomic Research Centre
- Mumbai-400085
- India
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27
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Gupta SK, Ghosh PS, Sahu M, Bhattacharyya K, Tewari R, Natarajan V. Intense red emitting monoclinic LaPO4:Eu3+ nanoparticles: host–dopant energy transfer dynamics and photoluminescence properties. RSC Adv 2015. [DOI: 10.1039/c5ra09076h] [Citation(s) in RCA: 70] [Impact Index Per Article: 7.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022] Open
Abstract
Visible host emission and dynamics of host–dopant energy transfer in LaPO4:Eu phosphor is investigated using PL and complimented by DFT.
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Affiliation(s)
- Santosh K. Gupta
- Radiochemistry Division
- Bhabha Atomic Research Centre
- Mumbai 400085
- India
| | - P. S. Ghosh
- Materials Science Division
- Bhabha Atomic Research Centre
- Mumbai 400085
- India
| | - M. Sahu
- Radioanalytical Chemistry Division
- Bhabha Atomic Research Centre
- Mumbai 400085
- India
| | - K. Bhattacharyya
- Chemistry Division
- Bhabha Atomic Research Centre
- Mumbai 400085
- India
| | - R. Tewari
- Materials Science Division
- Bhabha Atomic Research Centre
- Mumbai 400085
- India
| | - V. Natarajan
- Radiochemistry Division
- Bhabha Atomic Research Centre
- Mumbai 400085
- India
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Tewari R, Jarvela T, Linstedt AD. Manganese induces oligomerization to promote down-regulation of the intracellular trafficking receptor used by Shiga toxin. Mol Biol Cell 2014; 25:3049-58. [PMID: 25079690 PMCID: PMC4230593 DOI: 10.1091/mbc.e14-05-1003] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.2] [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] [Indexed: 01/01/2023] Open
Abstract
Manganese down-regulates the Shiga toxin receptor GPP130, which protects against lethal toxin doses. This study reveals a major aspect of the mechanism. Manganese binds GPP130, inducing GPP130 oligomerization, which is required and sufficient to redirect GPP130 out of the Golgi toward lysosomes. Manganese (Mn) protects cells against lethal doses of purified Shiga toxin by causing the degradation of the cycling transmembrane protein GPP130, which the toxin uses as a trafficking receptor. Mn-induced GPP130 down-regulation, in addition to being a potential therapeutic approach against Shiga toxicosis, is a model for the study of metal-regulated protein sorting. Significantly, however, the mechanism by which Mn regulates GPP130 trafficking is unknown. Here we show that a transferable trafficking determinant within GPP130 bound Mn and that Mn binding induced GPP130 oligomerization in the Golgi. Alanine substitutions blocking Mn binding abrogated both oligomerization of GPP130 and GPP130 sorting from the Golgi to lysosomes. Further, oligomerization was sufficient because forced aggregation, using a drug-controlled polymerization domain, redirected GPP130 to lysosomes in the absence of Mn. These experiments reveal metal-induced oligomerization as a Golgi sorting mechanism for a medically relevant receptor for Shiga toxin.
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Affiliation(s)
- Ritika Tewari
- Department of Biological Sciences, Carnegie Mellon University, Pittsburgh, PA 15213
| | - Timothy Jarvela
- Department of Biological Sciences, Carnegie Mellon University, Pittsburgh, PA 15213
| | - Adam D Linstedt
- Department of Biological Sciences, Carnegie Mellon University, Pittsburgh, PA 15213
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Patil MR, Mishra A, Jain N, Gutch M, Tewari R. Weight loss for reduction of proteinuria in diabetic nephropathy: Comparison with angiotensin-converting enzyme inhibitor therapy. Indian J Nephrol 2013; 23:108-13. [PMID: 23716916 PMCID: PMC3658287 DOI: 10.4103/0971-4065.109412] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.1] [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: 01/06/2023] Open
Abstract
Reduction of weight in obese type 2 diabetes mellitus (T2DM) individuals is emerging as a significant strategy in the reduction of proteinuria in diabetic nephropathy along with control of hyperglycemia, hypertension, and dyslipidemia. The objective was to evaluate the reduction in 24-h proteinuria in T2DM patients with nephropathy by weight loss, with conventional therapy (angiotensin-converting enzyme [ACE] inhibitors) as the control arm. A prospective, randomized controlled trial was conducted between June 2010 and May 2011. T2DM patients with confirmed nephropathy by 24-h urinary protein estimation with a body mass index (BMI) of >25 kg/m2 were studied. Patients who had nondiabetic nephropathy, uncontrolled hypertension (>125/75 mmHg) irrespective of antihypertensive drugs, excess weight due to edema or obesity due to other specific diseases, alcoholics, smokers, and patients who were on hemodialysis were excluded from the study. The patients were divided into three groups, namely, group A, patients on ACE inhibitor therapy; group B, patients on lifestyle modifications for weight loss; and group C, patients on an antiobesity drug (orlistat) and lifestyle modifications. At the end of 6 months, all the three groups were compared. Data were analyzed using software SPSS version 15.0. This study encompassed a total of 88 patients; 12 patients were dropped during the study period and 76 (group A: 22, group B: 23, and group C: 31) patients remained. The mean age of the patients was 58.36 ± 10.87 years (range: 30-70 years). At baseline, age, gender, mean BMI, waist-to-hip ratio (WHR), and 24-h proteinuria did not vary significantly among the three groups. At 6 months, the mean BMI significantly decreased in group C (P < 0.001) compared to that in the other two groups. Among the parameters BMI and WHR, the proportional form of BMI correlated well with the degree of reduction in proteinuria (r = 0.397, P = 0.01). Reduction in weight using lifestyle modifications and antiobesity drugs might improve renal function and proteinuria safely as observed in obese patients with diabetic nephropathy.
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Affiliation(s)
- M R Patil
- Department of Internal Medicine, C.S.M. Medical University, Lucknow, India
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Ghosh G, Panicker L, Ningthoujam R, Barick K, Tewari R. Counter ion induced irreversible denaturation of hen egg white lysozyme upon electrostatic interaction with iron oxide nanoparticles: A predicted model. Colloids Surf B Biointerfaces 2013. [DOI: 10.1016/j.colsurfb.2012.10.034] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/27/2022]
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Ingale S, Wagh P, Sastry P, Patra A, Tewari R, Singh I, Phapale S, Wasnik R, Rao A, Gupta S. Nanocrystalline Pentaerythritoltetranitrate using Sol-Gel Process. DEFENCE SCI J 2011. [DOI: 10.14429/dsj.61.594] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022]
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Mukherjee P, Roy M, Mandal BP, Choudhury S, Tewari R, Tyagi AK, Kale SP. Synthesis of uniform gold nanoparticles using non-pathogenic bio-control agent: evolution of morphology from nano-spheres to triangular nanoprisms. J Colloid Interface Sci 2011; 367:148-52. [PMID: 22047921 DOI: 10.1016/j.jcis.2011.08.085] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/01/2011] [Revised: 08/10/2011] [Accepted: 08/11/2011] [Indexed: 10/16/2022]
Abstract
Green synthesis of gold nanospheres with uniform diameter and triangular nanoprisms with optically flat surface was carried out using a non-pathogenic bio-control agent Trichoderma asperellum for reduction of HAuCl(4). Kinetics of the reaction was monitored by UV-Vis absorption spectroscopy. No additional capping/complexing agent was used for stabilizing the gold nanoparticles. Evolution of morphology from pseudospherical nanoparticles to triangular nanoprisms was studied by transmission electron microscopy (TEM). It revealed that three or more pseudospheres fused to form nanoprisms of different shapes and sizes. Slow rate of reduction of HAuCl(4) by constituents of cell-free fungal extract was instrumental in producing such exotic morphologies. Isolation of gold nanotriangles from the reacting masses was achieved by differential centrifugation.
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Affiliation(s)
- P Mukherjee
- NABT Division, Bhabha Atomic Research Centre, Mumbai 400 085, India
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Tewari R, Chaudhary A. Atypical Squamous Cells of Undetermined Significance : A Follow up Study. Med J Armed Forces India 2011; 66:225-7. [PMID: 27408306 DOI: 10.1016/s0377-1237(10)80042-5] [Citation(s) in RCA: 3] [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: 10/09/2009] [Accepted: 05/05/2010] [Indexed: 11/15/2022] Open
Abstract
BACKGROUND Atypical squamous cells of undetermined significance (ASCUS) is the term in cervical cytology reporting where the changes are suggestive of a sqamous extraepithelial lesion but lack criteria for definition interpretation. Its clinical significance is variable. METHODS A one year study in a zonal hospital evaluating all cervical smears received for cytology by two pathologists independently and subsequently reported as per the Bethesda guidelines. The patients were folloed up for six months. RESULT A total of 24 (4%) smears were reported as ASCUS out of 604 examined. Of these, 15 were followed up for one year. Mean age was 39 years and 60% were premenopausal. After six months, 11 cases were reported negative for intraepithelial lesion or malignancy and four showed ASCUS on repeat pap smear. CONCLUSION ASCUS shows a repression rate of 73%. Colpscopic evaluation should be done only if ASCUS persists. Diligent follow up and biopsy, when indicated is a must.
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Affiliation(s)
- R Tewari
- Classified Specialist (Pathology), Eastern Command Transfusion Centre, Kolkata
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Ghosh R, Pradhan L, Devi YP, Meena SS, Tewari R, Kumar A, Sharma S, Gajbhiye NS, Vatsa RK, Pandey BN, Ningthoujam RS. Induction heating studies of Fe3O4 magnetic nanoparticles capped with oleic acid and polyethylene glycol for hyperthermia. ACTA ACUST UNITED AC 2011. [DOI: 10.1039/c1jm10092k] [Citation(s) in RCA: 268] [Impact Index Per Article: 20.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
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Bhatti JS, Bhatti GK, Mastana SS, Ralhan S, Joshi A, Tewari R. ENPP1/PC-1 K121Q polymorphism and genetic susceptibility to type 2 diabetes in North Indians. Mol Cell Biochem 2010; 345:249-57. [PMID: 20820885 DOI: 10.1007/s11010-010-0579-2] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/18/2010] [Accepted: 08/19/2010] [Indexed: 12/21/2022]
Affiliation(s)
- Jasvinder Singh Bhatti
- Department of Biotechnology and Bioinformatics, Sri Guru Gobind Singh College, Chandigarh, 160019, India.
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Khan S, Bhakuni V, Praveen V, Tewari R, Tripathi CKM, Gupta VD. Maximizing the native concentration and shelf life of protein: a multiobjective optimization to reduce aggregation. Appl Microbiol Biotechnol 2010; 89:99-108. [DOI: 10.1007/s00253-010-2835-5] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/26/2010] [Revised: 08/08/2010] [Accepted: 08/09/2010] [Indexed: 11/27/2022]
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Biswal J, Ramnani S, Tewari R, Dey G, Sabharwal S. Short aspect ratio gold nanorods prepared using gamma radiation in the presence of cetyltrimethyl ammonium bromide (CTAB) as a directing agent. Radiat Phys Chem Oxf Engl 1993 2010. [DOI: 10.1016/j.radphyschem.2009.11.004] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
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40
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Tewari R, Friedrich C. Force Characterization and Rigidity Analysis of a Monolithic Cochlear Prosthesis Actuator. J Med Device 2009. [DOI: 10.1115/1.3147506] [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: 11/08/2022] Open
Abstract
Cochlear implants continue to be used in the treatment of profound deafness. Because of the tonotopic nature of the cochlea, more controlled insertion is perhaps the most important factor affecting device performance. The implant stiffness, and therefore the scala tympani (ST) wall contact force, contributes to insertion difficulties. Attempts to correlate the implant carrier structural properties and the intracochlear contact forces during insertion are limited. Researchers in the Michigan Center for Wireless Integrated Microsystems are developing perimodiolar-shaped silicon and parylene-based thin film cochlear electrode arrays and backing devices for a more controllable implantation. We report a method developed for measuring the thin film actuated electrode array rigidity to quantify the ST and modiolus wall contact forces during and after insertion. The method used a pneumatically actuated polyethylene terephthalate (PET) monolithic electrode actuator using pressurized air (0–200 kPa) for actuation. The prototype actuators consisted of PET tubes with an ID of 365 μm and a wall thickness of 58 μm. Force calculations using cantilever beam bending theory were performed to estimate the tube bending forces as a function of internal pressure and therefore variable structural stiffness. Based on estimations, a method was developed to measure such small forces avoiding the use of commercially available, relatively insensitive load cells. A fixture was fabricated incorporating two brass microcantilevers (reference and deflection arms) sensitive to sub-mN forces applied by the actuator on the deflection arm of the cantilevers. Microcantilver deflection data, captured by an interferometric microscope, was used to calculate the actuator force and eventually the reaction force acting on the actuator. The implant actuation forces ranged from 0–0.76 mN over an actuation pressure range of 0–140 kPa, from nearly straight to the relaxed perimodiolar post-implantation shape. For estimating the implant rigidity (EI), the actuator stiffness and the actuation pressure was correlated. The actuator stiffness at different actuation pressures was obtained both theoretically (using beam bending theory and PET tube structural properties) and experimentally (using the derived unconstrained actuator deflections at measured actuator forces). The theoretical and experimental stiffness values ranged from 3.6E-08 to 5.34E-07 N/μm and 2.5E-08 to 7.8E-06 N/μm respectively over the working pressure range. The calculated rigidity constant (EI) of the best prototype insertion tool from the experimental stiffness measurement was 6.71E06 Nμm2. The insertion tool-ST wall contact forces were calculated, using the estimated rigidity, in a hypothetical insertion situation. Force calculations assumed that the implant is equipped with actuator deflection feedback sensors and the actuator's stiffness remains constant over its entire length for a given operating pressure. A contact force of 1.19 mN was found acting on the cochlear ST wall when the insertion tool hits the wall and deflects by 200 μm at an actuation pressure of 140 kPa.
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Affiliation(s)
- R. Tewari
- Michigan Technological University, Houghton, MI 49931, USA
| | - C. Friedrich
- Michigan Technological University, Houghton, MI 49931, USA
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Abstract
Most of the complications of pre-term delivery arise in the 1 - 2% of births before 32 weeks' gestation. However, late pre-term birth (32 - 36 weeks' gestation) is still worrying for the mother and clinician. In a retrospective study that compared the management and outcome of 103 singleton pregnancies delivered between 32 and 36 weeks' of gestation with 103 age-matched controls that delivered at term, a short inter-pregnancy interval, early pregnancy bleeding, pre-labour spontaneous rupture of membranes, a history of pre-term delivery and Asian race or single marital status were found to be significant factors. The groups did not differ in parity, BMI, smoking status or history of miscarriages and terminations. Following a logistic regression analysis, the following emerged as risk factors for late pre-term delivery; a history of previous pre-term delivery (OR = 7.2; 95% CI 1.6 - 33.2), a short (<12 months) inter-pregnancy interval (OR = 4.1; 95% CI 2.2 - 7.5), early pregnancy bleeding (OR = 7.6; 95% CI 1.3 - 38.3) and pre-labour spontaneous rupture of membranes (OR = 13.3, 95% CI 3.1 - 55.2).
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Affiliation(s)
- D O Selo-Ojeme
- Department of Obstetrics and Gynaecology, Barnet and Chase Farm Hospitals NHS Trust, Enfield, UK.
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42
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Naidu B, Pandey M, Sudarsan V, Vatsa R, Tewari R. Photoluminescence and Raman spectroscopic investigations of morphology assisted effects in Sb2O3. Chem Phys Lett 2009. [DOI: 10.1016/j.cplett.2009.04.050] [Citation(s) in RCA: 40] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
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Salam M, Dahiya N, Sharma R, Soni SK, Hoondal GS, Tewari R. Cloning, characterization and expression of the chitinase gene of Enterobacter sp. NRG4. Indian J Microbiol 2009; 48:358-64. [PMID: 23100735 DOI: 10.1007/s12088-008-0044-z] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.4] [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: 08/25/2007] [Accepted: 11/22/2007] [Indexed: 10/21/2022] Open
Abstract
A chitinase producing bacterium Enterobacter sp. NRG4, previously isolated in our laboratory, has been reported to have a wide range of applications such as anti-fungal activity, generation of fungal protoplasts and production of chitobiose and N-acetyl D-glucosamine from swollen chitin. In this paper, the gene coding for Enterobacter chitinase has been cloned and expressed in Escherichia coli BL21(DE3). The structural portion of the chitinase gene comprised of 1686 bp. The deduced amino acid sequence of chitinase has high degree of homology (99.0%) with chitinase from Serratia marcescens. The recombinant chitinase was purified to near homogeneity using His-Tag affinity chromatography. The purified recombinant chitinase had a specific activity of 2041.6 U mg(-1). It exhibited similar properties pH and temperature optima of 5.5 and 45°C respectively as that of native chitinase. Using swollen chitin as a substrate, the K(m), k(cat) and catalytic efficiency (k(cat)/K(m)) values of recombinant chitinase were found to be 1.27 mg ml(-1), 0.69 s(-1) and 0.54 s(-1)M(-1) respectively. Like native chitinase, the recombinant chitinase produced medicinally important N-acetyl D-glucosamine and chitobiose from swollen chitin and also inhibited the growth of many fungi.
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Affiliation(s)
- M Salam
- Microbial Biotechnology Laboratory, Department of Biotechnology, Panjab University, Chandigarh, India
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Ningthoujam RS, Umare SS, Sharma SJ, Shukla R, Kurian S, Vatsa RK, Tyagi AK, Tewari R, Dey GK, Gajbhiye NS. Magnetic and Mössbauer studies on nanocrystalline Co1−x Li x Fe2O4 (x = 0, 0.2). ACTA ACUST UNITED AC 2008. [DOI: 10.1007/s10751-008-9794-6] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
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Gupta PR, Tewari R, Singh AK, Kumar A. Ruptured sinus of valsalva into right ventricle: a unique case with prolonged survival. J Assoc Physicians India 2006; 54:126. [PMID: 16715617] [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] [Subscribe] [Scholar Register] [Indexed: 05/09/2023]
Affiliation(s)
- P R Gupta
- Department of Cardiology, Institute of Medical Sciences, Banaras Hindu University, Varanasi
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Dahiya N, Tewari R, Tiwari RP, Hoondal GS. Production of an Antifungal Chitinase from Enterobacter sp. NRG4 and its Application in Protoplast Production. World J Microbiol Biotechnol 2005. [DOI: 10.1007/s11274-005-8343-6] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/25/2022]
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Shafiani S, Sharma P, Vohra RM, Tewari R. Cloning and characterization of aspartate-beta-semialdehyde dehydrogenase from Mycobacterium tuberculosis H37 Rv. J Appl Microbiol 2005; 98:832-8. [PMID: 15752328 DOI: 10.1111/j.1365-2672.2004.02505.x] [Citation(s) in RCA: 16] [Impact Index Per Article: 0.8] [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: 11/27/2022]
Abstract
AIMS To clone and characterize the aspartate-beta-semialdehyde dehydrogenase of Mycobacterium tuberculosis H37Rv. METHODS AND RESULTS The asd gene of M. tuberculosis H37Rv was cloned in pGEM-T Easy vector, subcloned in expression vector pQE30 having a T5 promoter, and overexpressed in Escherichia coli. The ASD enzyme was expressed to levels of 40% but was found to be inactive. Functional ASD was obtained by altering induction and growth conditions and the enzyme was purified to near homogeneity using nickel-nitrilotriacetic acid (Ni-NTA) affinity chromatography. The K(m) and V(max) values for the three substrates L-ASA, NADP and Pi, the turnover number and specific activity of the enzyme were determined. CONCLUSIONS Functional ASD enzyme of M. tuberculosis was obtained by gene cloning and protein purification using affinity chromatography. The K(cat) and specific activity of the enzyme were 8.49 s(-1) and 13.4 micromol min(-1) microg(-1) respectively. SIGNIFICANCE AND IMPACT OF THE STUDY The ASD enzyme is a validated drug target. We characterized this enzyme from M. tuberculosis and future work would focus on deducing the three-dimensional structure of the enzyme and design of inhibitors, which could be used as drugs against TB.
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Affiliation(s)
- S Shafiani
- Microbial Biotechnology Laboratory, Department of Biotechnology, Panjab University, Chandigarh, Punjab 160014, India
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Hoondal GS, Tiwari RP, Tewari R, Dahiya N, Beg QK. Microbial alkaline pectinases and their industrial applications: a review. Appl Microbiol Biotechnol 2002; 59:409-18. [PMID: 12172603 DOI: 10.1007/s00253-002-1061-1] [Citation(s) in RCA: 184] [Impact Index Per Article: 8.4] [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: 04/03/2002] [Revised: 05/27/2002] [Accepted: 06/01/2002] [Indexed: 11/24/2022]
Abstract
The biotechnological potential of pectinolytic enzymes from microorganisms has drawn a great deal of attention from various researchers worldwide as likely biological catalysts in a variety of industrial processes. Alkaline pectinases are among the most important industrial enzymes and are of great significance in the current biotechnological arena with wide-ranging applications in textile processing, degumming of plant bast fibers, treatment of pectic wastewaters, paper making, and coffee and tea fermentations. The present review features the potential applications and uses of microbial alkaline pectinases, the nature of pectin, and the vast range of pectinolytic enzymes that function to mineralize pectic substances present in the environment. It also emphasizes the environmentally friendly applications of microbial alkaline pectinases thereby revealing their underestimated potential. The review intends to explore the potential of these enzymes and to encourage new alkaline pectinase-based industrial technology.
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Affiliation(s)
- G S Hoondal
- Department of Microbiology, Panjab University, Chandigarh 160 014, India.
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Tewari R, Singh MP, Farheen S, Dikshit M, Mehrotra PK. Inhibition of platelet aggregation by rat trophoblasts. Med Princ Pract 2002; 11:100-4. [PMID: 12123100 DOI: 10.1159/000058015] [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] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/19/2022] Open
Abstract
OBJECTIVE To determine the effect of rat trophoblast cell suspensions on adenosine diphosphate (ADP)-induced platelet aggregation. MATERIALS AND METHODS The trophoblasts were isolated from ectoplacental cones (a preplacental tissue very rich in trophoblasts) developed in rat embryos on day 12 of pregnancy (normal period of gestation: 22-23 days). Platelet-rich plasma (PRP) was obtained from adult male rats. The trophoblasts were preincubated (37 degrees C, 30 min), suspended in the medium, and then re-incubated with PRP for 3-5 min. RESULTS 5 x 10(4) and 7 x 10(4) trophoblasts inhibited ADP-induced platelet aggregation by 10 and 18%, respectively. When the trophoblast cell concentration was increased to 1-2 x 10(5) cells, a proaggregatory phenomenon was observed, even in the absence of ADP. However, there was no inhibition of aggregation or promotion of aggregation when fixed trophoblasts or live endometrial stromal cells were incubated with PRP. CONCLUSION The results indicate that the aggregation inhibition response was cell specific and concentration dependent. A 68-kD protein was detected in the medium when it was conditioned with 5-7 x 10(4) but not with 1-2 x 10(5) trophoblasts. However, the inhibitory or stimulatory effect does not seem to be dependent on the presence of this protein.
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Affiliation(s)
- R Tewari
- Division of Endocrinology, Central Drug Research Institute, Lucknow, India
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50
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Chaturvedi G, Tewari R, Agnihotri N, Vishwakarma RA, Ganguly NK. Inhibition of Helicobacter pylori adherence by a peptide derived from neuraminyl lactose binding adhesin. Mol Cell Biochem 2001; 228:83-9. [PMID: 11855744 DOI: 10.1023/a:1013314604403] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.3] [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: 11/12/2022]
Abstract
Helicobacterpylori, like many other gut colonizing bacteria, binds to sialic acid rich macromolecules present on the gastric epithelium. NLBH (neuraminyl lactose binding haemagglutinin) a 32 kDa adhesin located on the surface of H. pylori has been shown to have specific affinity towards NeuAcalpha2,3Galbeta1,4Gluc(3'SL). This sialic acid moiety is over-expressed in an atrophic stomach undergoing parietal cell depletion. Antibodies against a lysine rich peptide fragment of NLBH inhibit agglutination of human erythrocytes. This lysine rich sequence from NLBH was proposed to be the receptor-binding site. In order to elucidate the binding of NLBH to gastric epithelium, a peptide (D-P-K-R-T-I-Q-K-K-S) was synthesized. A series of experiments were performed involving adherence inhibition assays, 2D-NMR, molecular modelling and measurement of modulation in acid secretion. Results indicated that the peptide fragment could be involved in receptor recognition, which is important for the binding of H. pylori to gastric epithelium. The binding is possibly through hydrogen bonding. Two lysines and a threonine residue seem to be within the hydrogen bonding distance of NeuAcalpha2,3Galbeta1,4Gluc. Further, in vitro assays were performed to evaluate the role of the peptide on acid secretion by parietal cells isolated from human fundal biopsies. Interestingly, the peptide increases acid secretion only in H. pylori negative and in treated patients but not in H. pylori positive patients. This highlights the role of NLBH in acid secretion and could be of some consequence in the prognosis of the disease.
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Affiliation(s)
- G Chaturvedi
- Department of Microbiology, Panjab University, Chandigarh, India
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