Publications by authors named "Om Srivastava"

Stable isotope labeled standards of all major human lens crystallins were created to measure the abundance of lens endogenous crystallins from birth to adulthood. All major human crystallins (αA, αB, βA2, βA3/A1, βA4, βB1, βB2, βB3, γA, γB, γC, γD, γS) were cloned with N-terminal 6 x His tagged SUMO for ease of purification and the ability to generate natural N-termini by SUMO protease cleavage when producing crystallins for structure/function studies. They were then expressed in N-enriched media, quantified by mass spectrometry, and mixed in proportions found in young human lens to act as an artificial lens standard.

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Purpose: To examine lens phenotypic characteristics in βA3ΔG91 mice and determine if βA3ΔG91 affects autophagy in the lens.

Methods: We generated a βA3ΔG91 mouse model using CRISPR/Cas9 methodology. Comparative phenotypic and biochemical characterizations of lenses from postnatal day 0 (P0), P15, and 1-month-old βA3ΔG91 and wild-type (WT) mice were performed.

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Purpose: To determine the role of fibroblast growth factor receptor 2 (FGFR2)-mediated signaling in keratocytes during corneal development, a keratocyte-specific FGFR2-knockout (named FGFR2cKO) mouse model was generated, and its phenotypic characteristics were determined.

Methods: A FGFR2cKO mouse model was generated by the following method: FGFR2 flox mice were crossed with the inducible keratocyte specific-Cre mice (Kera-rtTA/tet-O-Cre). Both male and female FGFR2cKO- and control mice (1 to 3-months-old) were analyzed for changes in corneal topography and pachymetry maps using the optical coherence tomography (OCT) method.

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βA3/A1-crystallin is a lens structural protein that plays an important role in maintaining lens transparency via interactions with other crystallins. While the function of βA3/A1-crystallin in the retina is well studied, its functions in the lens, other than as a structural protein, remain unclear. In the current study, we generated the lens-specific βA3/A1-crystallin conditional knockout mouse (named βA3/A1ckO) and explored phenotypic changes and the function of the crystallin in the lens.

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Purpose: To identify and characterize properties of αA- and αB-crystallins' low molecular weight peptides (molecular weight [Mr] < 5 kDa) that were present in a 62-year-old human nuclear cataract, but not in normal 62-year-old human lenses.

Methods: Low molecular weight peptides (< 5 kDa) were isolated with a trichloroacetic acid (TCA) solubilization method from water-soluble (WS) and water-insoluble (WI) proteins of nuclear cataractous lenses of a 62-year-old donor and normal human lenses from an age-matched donor. Five commercially synthesized peptides (found only in cataractous lenses and not in normal lenses) were used to determine their chaperone and antichaperone activity and aggregation properties.

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Unlabelled: We have generated two mouse models, in one by inserting the human lens αAN101D transgene in CRYαA mice, and in the other by inserting human wild-type αA-transgene in CRYαA mice. The CRYαA mice developed cortical cataract at about 7-months of age relative to CRYαA mice. The objective of the study was to determine the following relative changes in the lenses of CRYαA- vs.

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The overall goal was to generate an epithelial-mesenchymal transition (EMT) model using lens epithelial cells-induced pluripotent stem cells to elucidate EMT-regulatory factors during posterior capsular opacification (PCO). For this purpose, the mouse lens epithelial cells-derived mesenchymal cells were reprogrammed to induced pluripotent stem cells (iPSC) and differentiated to lens epithelial cells to be used to determine regulatory factors during EMT. Lens epithelial cells from one-month-old C57BL/6 mice were transitioned to mesenchymal cells in culture, and were reprogrammed to iPSC by delivering reprogramming factors in a single polycistronic lentiviral vector (co-expressing four transcription factors, Oct 4, Sox2, Klf4, and Myc).

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The aim of this study was to determine relative importance of N-terminal domain and C-terminal extension of αA-crystallin during their in vitro complex formation with phakinin and filensin (the two lens-specific intermediate filament [IF] proteins). Cloned phakinin, filensin and vimentin were purified under a denaturing conditions by consecutive DEAE-cellulose-, hydroxyapatite- and Sephadex G-75-column chromatographic methods. WTαA-crystallin, αA-NT (N-terminal domain [residue number 1-63])-deleted and αA-CT (C-terminal terminal extension [residue number 140-173]-deleted), were cloned in pET 100 TOPO vector, expressed in BL-21 (DE3) cells using 1% IPTG, and purified using a Ni-affinity column.

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Persistent fetal vasculature (PFV) occurs as a result of a failure of fetal vasculature to undergo normal programmed involution. During development, before the formation of retinal vessels, the lens and the inner retina are nourished by the hyaloid vasculature. Hyaloid vessels extend from the optic nerve and run through the vitreous to encapsulate the lens.

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Purpose: To model keratoconus (KC) using induced pluripotent stem cells (iPSC) generated from fibroblasts of both KC and normal human corneal stroma by a viral method.

Methods: Both normal and KC corneal fibroblasts from four human donors were reprogramed directly by delivering reprogramming factors in a single virus using 2A "self-cleaving" peptides, using a single polycistronic lentiviral vector coexpressing four transcription factors (Oct 4, Sox2, Klf4, and Myc) to yield iPSC. These iPS cells were characterized by immunofluorescence detection using of stem cell markers (SSEA4, Oct4, and Sox2).

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βA3/A1-crystallin is an abundant structural protein of the lens that is very critical for lens function. Many different genetic mutations have been shown to associate with different types of cataracts in humans and in animal models. βA3/A1-crystallin has four Greek key-motifs that organize into two crystallin domains.

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Tenofovir induced fanconi syndrome (FS) presenting as hypokalemic paralysis is an extremely rare complication in patients on anti-retroviral therapy. We report a 50-year-old male with acquired immunodeficiency syndrome on tenofovir-based anti-retroviral therapy who presented with acute onset quadriparesis. On evaluation, he was found to have hypokalemia with hypophosphatemia, glucosuria and proteinuria suggesting FS.

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Interaction among crystallins is required for the maintenance of lens transparency. Deamidation is one of the most common post-translational modifications in crystallins, which results in incorrect interaction and leads to aggregate formation. Various studies have established interaction among the α- and β-crystallins.

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Purpose: The CRYAAN101D transgenic mouse model expressing deamidated αA-crystallin (deamidation at N101 position to D) develops cortical cataract at the age of 7 to 9 months. The present study was carried out to explore the molecular mechanism that leads to the development of cortical opacity in CRYAAN101D lenses.

Methods: RNA sequence analysis was carried out on 2- and 4-month-old αA-N101D and wild type (WT) lenses.

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Purpose: The purpose of this study was to determine the expression levels and regulation of β-actin in the stroma of keratoconus (KC) and normal corneas.

Methods: A total of 15 different human corneas from both KC and normal individuals were used for this study. Additionally, 3 Fuch's dystrophic corneas were also used.

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To elucidate the morphological and cellular changes due to introduction of a charge during development and the possible mechanism that underlies cataract development in humans as a consequence of an additional charge, we generated a transgenic mouse model mimicking deamidation of Asn at position 101. The mouse model expresses a human αA-crystallin gene in which Asn-101 was replaced with Asp, which is referred to as αAN101D-transgene and is considered to be "deamidated" in this study. Mice expressing αAN101D-transgene are referred to here CRYAA(N101D) mice.

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Cataract-related loss of vision affects large numbers of people in today's aging populations and presents a healthcare burden to many nations. The role of dietary supplements within the lens is largely unknown, although benefits from dietary anti-oxidants are expected. In this study, the effects of genistein as its aglycone, a genistein-containing dietary supplement (Novasoy(®)200), and a genistein-containing food (soy protein isolate, PRO-FAM 932) on the development of lens opacity were examined in the hereditary cataractous ICR/f rat.

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Our recent study has shown that betaA3-crystallin along with betaB1- and betaB2-crystallins were part of high molecular weight complex obtained from young, old, and cataractous lenses suggesting potential interactions between alpha- and beta-crystallins (Srivastava, O. P., Srivastava, K.

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Sialyl Lewis(a) (sLe(a)), also termed CA19-9 antigen, is recognized by murine mAb19-9 and is expressed on the cancer cell surface as a glycolipid and as an O-linked glycoprotein. It is highly expressed in a variety of gastrointestinal epithelial malignancies including colon cancer and pancreatic cancer, and in breast cancer and small cell lung cancer, but has a limited expression on normal tissues. sLe(a) is known to be the ligand for endothelial cell selectins suggesting a role for sLe(a) in cancer metastases and adhesion.

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MS, with or without pre-analysis peptide fractionation, can be used to decipher the residues on proteins where oxidative modifications caused by peroxynitrite, singlet oxygen or electrophilic lipids have occurred. Peroxynitrite nitrates tyrosine and tryptophan residues on the surface of actin. Singlet oxygen, formed by the interaction of UVA light with tryptophan, can oxidize neighbouring cysteine, histidine, methionine, tyrosine and tryptophan residues.

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The purpose of the study was to compare the effects of deamidation alone, truncation alone, or both truncation and deamidation on structural and functional properties of human lens alphaA-crystallin. Specifically, the study investigated whether deamidation of one or two sites in alphaA-crystallin (i.e.

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Purpose: The purpose of the study was to determine molecular changes in selected epithelial proteins in human keratoconus (KC) corneas compared to normal corneas.

Methods: Two-dimensional (2-D) gel electrophoretic profiles of epithelial cell proteins from normal and keratoconus corneas were compared, and the selected protein spots that showed either up- or downregulation were identified. The desired spots were identified after trypsin digestion and mass spectrometric analysis.

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In a previous article, the authors reported that exposing wild-type enteropathogenic Escherichia coli (EPEC) to chemically synthesized N-acetyllactosamine glycosides covalently coupled to BSA (LacNAc-BSA) inhibited localized adherence (LA) by these organisms and also caused them to lose their bundle-forming pili (BFP), the filamentous surface appendages responsible for their LA phenotype. This effect has now been further investigated by screening a panel of LacNAc-BSA-related glycosides for their ability to inhibit EPEC LA, which revealed that LacNAc-BSA retained its status as the most effective inhibitor of EPEC LA. It was also shown that LacNAc-BSA did not cause the loss of BFP in an EPEC strain containing a non-polar mutation in the bfpF gene and, as a consequence, unable to retract its BFP.

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Purpose: The aim of the study was to comparatively analyze crystallin fragments in the water soluble high molecular weight (WS-HMW) and in the water insoluble (WI) protein fractions of human cataractous (with nuclear opacity) and age matched normal lenses to determine the identity of crystallin species that show cataract specific changes such as truncation and post-translational modifications. Because these changes were cataract specific and not aging specific, the results were expected to provide information regarding potential mechanisms of age related cataract development.

Methods: The WS-alpha-crystallin, WS-HMW protein, and WI protein fractions were isolated from normal lenses of different ages and from cataractous lenses.

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To determine the effects of deamidation on structural and functional properties of alphaA-crystallin, three mutants (N101D, N123D, and N101D/N123D) were generated. Deamidated alphaB-crystallin mutants (N78D, N146D, and N78D/N146D), characterized in a previous study (Gupta, R., and Srivastava, O.

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