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1.
Int J Mol Sci ; 22(1)2020 Dec 31.
Article in English | MEDLINE | ID: mdl-33396557

ABSTRACT

An enigmatic localized pneumonia escalated into a worldwide COVID-19 pandemic from Severe Acute Respiratory Syndrome Coronavirus 2 (SARS-CoV-2). This review aims to consolidate the extensive biological minutiae of SARS-CoV-2 which requires decipherment. Having one of the largest RNA viral genomes, the single strand contains the genes ORF1ab, S, E, M, N and ten open reading frames. Highlighting unique features such as stem-loop formation, slippery frameshifting sequences and ribosomal mimicry, SARS-CoV-2 represents a formidable cellular invader. Hijacking the hosts translational engine, it produces two polyprotein repositories (pp1a and pp1ab), armed with self-cleavage capacity for production of sixteen non-structural proteins. Novel glycosylation sites on the spike trimer reveal unique SARS-CoV-2 features for shielding and cellular internalization. Affording complexity for superior fitness and camouflage, SARS-CoV-2 challenges diagnosis and vaccine vigilance. This review serves the scientific community seeking in-depth molecular details when designing drugs to curb transmission of this biological armament.


Subject(s)
COVID-19/virology , SARS-CoV-2/genetics , SARS-CoV-2/metabolism , Viral Proteins/metabolism , COVID-19/genetics , COVID-19/metabolism , Humans , Open Reading Frames , Pandemics , Phylogeny , RNA, Viral/genetics
3.
Cereb Cortex ; 27(10): 4733-4749, 2017 10 01.
Article in English | MEDLINE | ID: mdl-27600841

ABSTRACT

Synaptic dysfunctions and altered neuronal activity play major role in the pathophysiology of Alzheimer's disease (AD), with underlying mechanisms largely unknown. We report that in the prefrontal cortex of amyloid precursor protein-presenilin 1 and APP23 AD mice, baseline activity of pyramidal cells is disrupted by episodes of paroxysmal hyperactivity. Induced by spontaneous EPSC bursts, these incidents are prevalent in neurons proximal to amyloid plaques and involve enhanced activity of glutamate with metabotropic effects. Abolition of EPSC bursts by tetrodotoxin and SERCA ATPase blockers thapsigargin or cyclopiasonic acid suggests their presynaptic origin and sensitized store-released calcium. Accordingly, the rate of EPSC bursts activated by single axon stimulation is enhanced. Aggravation of the hyperactivity by blockers of excitatory amino acid transporter (±)-HIP-A and DL-TBOA together with histochemical and ultrastructural evidence for enrichment of plaque-related dystrophies with synaptic vesicles and SNARE protein SNAP-25 infer the later as hot-spots for ectopic release of glutamate. Inhibition of EPSC bursts by I/II mGluR1 blocker MCPG or selective mGluR1 antagonist LY367385 implicate metabotropic glutamatergic effects in generation of paroxysmal bursts. These findings demonstrate for the first time that at amyloid plaques, enhanced activity of nonsynaptic glutamate can promote irregular EPSC bursts with hyperactivity of pyramidal cells via mGluR1 receptors.


Subject(s)
Excitatory Postsynaptic Potentials/drug effects , Glutamic Acid/metabolism , Receptors, Metabotropic Glutamate/metabolism , Animals , Benzoates/pharmacology , Excitatory Amino Acid Antagonists/pharmacology , Excitatory Postsynaptic Potentials/physiology , Glycine/analogs & derivatives , Glycine/pharmacology , Mice, Inbred C57BL , Neurons/drug effects , Neurons/physiology , Plaque, Amyloid/metabolism , Pyramidal Cells/drug effects , Receptors, Presynaptic/drug effects , Synaptic Transmission/physiology
4.
Mol Imaging Biol ; 2024 09 30.
Article in English | MEDLINE | ID: mdl-39348040

ABSTRACT

Botulinum neurotoxins (BoNTs) and tetanus toxin (TeTX) are the deadliest biological substances that cause botulism and tetanus, respectively. Their astonishing potency and capacity to enter neurons and interfere with neurotransmitter release at presynaptic terminals have attracted much interest in experimental neurobiology and clinical research. Fused with reporter proteins or labelled with fluorophores, BoNTs and TeTX and their non-toxic fragments also offer remarkable opportunities to visualize cellular processes and functions in neurons and synaptic connections. This study presents the state-of-the-art optical probes derived from BoNTs and TeTX and discusses their applications in molecular and synaptic biology and neurodevelopmental research. It reviews the principles of the design and production of probes, revisits their applications with advantages and limitations and considers prospects for future improvements. The versatile characteristics of discussed probes and reporters make them an integral part of the expanding toolkit for molecular neuroimaging, promoting the discovery process in neurobiology and translational neurosciences.

5.
Mol Imaging Biol ; 25(5): 799-814, 2023 10.
Article in English | MEDLINE | ID: mdl-37468801

ABSTRACT

The superb specificity and potency of biological toxins targeting various ion channels and receptors are of major interest for the delivery of therapeutics to distinct cell types and subcellular compartments. Fused with reporter proteins or labelled with fluorophores and nanocomposites, animal toxins and their detoxified variants also offer expanding opportunities for visualisation of a range of molecular processes and functions in preclinical models, as well as clinical studies. This article presents state-of-the-art optical probes derived from neurotoxins targeting ion channels, with discussions of their applications in basic and translational biomedical research. It describes the design and production of probes and reviews their applications with advantages and limitations, with prospects for future improvements. Given the advances in imaging tools and expanding research areas benefiting from the use of optical probes, described here resources should assist the discovery process and facilitate high-precision interrogation and therapeutic interventions.


Subject(s)
Diagnostic Imaging , Neurotoxins , Animals , Fluorescent Dyes , Ion Channels , Optical Imaging/methods
6.
Biomedicines ; 10(11)2022 Nov 11.
Article in English | MEDLINE | ID: mdl-36428462

ABSTRACT

Adaptive immunity changes over an individual's lifetime, maturing by adulthood and diminishing with old age. Epigenetic mechanisms involving DNA and histone methylation form the molecular basis of immunological memory during lymphocyte development. Monocytes alter their function to convey immune tolerance, yet the epigenetic influences at play remain to be fully understood in the context of lifespan. This study of a healthy genetically homogenous cohort of children, adults and seniors sought to decipher the epigenetic dynamics in B-lymphocytes and monocytes. Variable global cytosine methylation within retro-transposable LINE-1 repeats was noted in monocytes compared to B-lymphocytes across age groups. The expression of the human leukocyte antigen (HLA)-DQ alpha chain gene HLA-DQA1*01 revealed significantly reduced levels in monocytes in all ages relative to B-lymphocytes, as well as between lifespan groups. High melting point analysis and bisulfite sequencing of the HLA-DQA1*01 promoter in monocytes highlighted variable cytosine methylation in children and seniors but greater stability at this locus in adults. Further epigenetic evaluation revealed higher histone lysine 27 trimethylation in monocytes from this adult group. Chromatin immunoprecipitation and RNA pulldown demonstrated association with a novel lncRNA TINA with structurally conserved similarities to the previously recognized epigenetic modifier PARTICLE. Seeking to interpret the epigenetic immunological landscape across three representative age groups, this study focused on HLA-DQA1*01 to expose cytosine and histone methylation alterations and their association with the non-coding transcriptome. Such insights unveil previously unknown complex epigenetic layers, orchestrating the strength and weakening of adaptive immunity with the progression of life.

7.
J Immunol Res ; 2019: 7406810, 2019.
Article in English | MEDLINE | ID: mdl-31687413

ABSTRACT

In Alzheimer's disease (AD), tau pathology manifested by the accumulation of intraneuronal tangles and soluble toxic oligomers emerges as a promising therapeutic target. Multiple anti-tau antibodies inhibiting the formation and propagation of cytotoxic tau or promoting its clearance and degradation have been tested in clinical trials, albeit with the inconclusive outcome. Antibodies against tau protein have been documented both in the brain circulatory system and at the periphery, but their origin and role under normal conditions and in AD remain unclear. While it is tempting to assign them a protective role in regulating tau level and removal of toxic variants, the supportive evidence remains sporadic, requiring systematic analysis and critical evaluation. Herein, we review recent data showing the occurrence of tau-reactive antibodies in the brain and peripheral circulation and discuss their origin and significance in tau clearance. Based on the emerging evidence, we cautiously propose that impairments of tau clearance at the periphery by humoral immunity might aggravate the tau pathology in the central nervous system, with implication for the neurodegenerative process of AD.


Subject(s)
Alzheimer Disease/etiology , Autoantibodies/immunology , Autoantigens/immunology , Disease Susceptibility , tau Proteins/immunology , Alzheimer Disease/metabolism , Alzheimer Disease/pathology , Alzheimer Disease/therapy , Animals , Autoantibodies/blood , Humans , Immunoglobulins, Intravenous/therapeutic use , Immunotherapy , tau Proteins/metabolism
8.
Neurotherapeutics ; 15(4): 1032-1035, 2018 10.
Article in English | MEDLINE | ID: mdl-30242774

ABSTRACT

While the extensive hunt for therapeutics combating Alzheimer's disease (AD) has fallen short of delivering effective treatments, breakthroughs towards understanding the disease mechanisms and identifying areas for future research have nevertheless been enabled. The majority of clinical trials with ß- and γ-secretase modulators have been suspended from additional studies or terminated due to toxicity issues and health concerns. The lack of progress in developing innovative AD therapies has also prompted a resurgence of interest in more traditional symptomatic treatments with cholinesterase inhibitors and N-methyl-D-aspartate receptor antagonists, as well as in the research of immune response modulators. Recently, evidence has emerged showing that inhibitors of arginine metabolism and in particular blockers of arginase, an enzyme that catalyzes the breakdown of L-arginine, could present an effective therapeutic candidate for halting the progression of AD and boosting cognition and memory. In this commentary, we present a brief overview of reports on arginase inhibitors in AD mouse models and discuss emerging advantages and areas for careful consideration on the road to clinical translation.


Subject(s)
Alzheimer Disease/drug therapy , Arginase/antagonists & inhibitors , Arginase/metabolism , Enzyme Inhibitors/therapeutic use , Humans
9.
Oncotarget ; 8(50): 87431-87441, 2017 Oct 20.
Article in English | MEDLINE | ID: mdl-29152092

ABSTRACT

Breakage of the fragile site FRA16D disrupts the WWOX (WW Domain Containing Oxidoreductase) tumor suppressor gene in osteosarcoma. However, the frequency of breakage is not sufficient to explain the rate of WWOX loss in pathogenesis. The involvement of non-coding RNA transcripts is proposed due to their accumulation at fragile sites, where they are advocated to influence specific chromosomal regions associated with malignancy. The long ncRNA PARTICLE (promoter of MAT2A antisense radiation-induced circulating long non-coding RNA) is transiently elevated in response to irradiation and influences epigenetic silencing modification within WWOX. It now emerges that elevated PARTICLE levels are significantly associated with FRA16D non-breakage in OS patients. Although not associated with overall survival, high PARTICLE levels were found to be significantly linked to metastasis free outcome. The transcription of both PARTICLE and WWOX are transiently responsive to exposure to low doses of radiation in osteosarcoma cell lines. Herein, a relationship between WWOX and PARTICLE transcription is suggested in human osteosarcoma cell lines representing alternative genetic backgrounds. PARTICLE over-expression ameliorated WWOX promoter activity in U2OS harboring FRA16D non-breakage. It can be concluded that the lncRNA PARTICLE influences the WWOX tumor suppressor and in the absence of WWOX FRA16D breakage, it is associated with OS metastasis-free survival.

10.
Sci Rep ; 7(1): 1790, 2017 05 11.
Article in English | MEDLINE | ID: mdl-28496150

ABSTRACT

PARTICLE (Gene PARTICL- 'Promoter of MAT2A-Antisense RadiaTion Induced Circulating LncRNA) expression is transiently elevated following low dose irradiation typically encountered in the workplace and from natural sources. This long non-coding RNA recruits epigenetic silencers for cis-acting repression of its neighbouring Methionine adenosyltransferase 2A gene. It now emerges that PARTICLE operates as a trans-acting mediator of DNA and histone lysine methylation. Chromatin immunoprecipitation sequencing (ChIP-seq) and immunological evidence established elevated PARTICLE expression linked to increased histone 3 lysine 27 trimethylation. Live-imaging of dbroccoli-PARTICLE revealing its dynamic association with DNA methyltransferase 1 was confirmed by flow cytometry, immunoprecipitation and direct competitive binding interaction through electrophoretic mobility shift assay. Acting as a regulatory docking platform, the long non-coding RNA PARTICLE serves to interlink epigenetic modification machineries and represents a compelling innovative component necessary for gene silencing on a global scale.


Subject(s)
DNA Methylation , Histones/metabolism , RNA, Long Noncoding/genetics , Cell Line, Tumor , CpG Islands , DNA (Cytosine-5-)-Methyltransferase 1/genetics , DNA Methylation/radiation effects , Epistasis, Genetic , Gene Expression Profiling , Genome, Human , Humans , Methylation , Radiation, Ionizing , Tumor Suppressor Proteins/genetics , WW Domain-Containing Oxidoreductase/genetics
11.
Oncotarget ; 8(45): 78397-78409, 2017 Oct 03.
Article in English | MEDLINE | ID: mdl-29108237

ABSTRACT

Generated by Quaking (QKI), circular RNAs (circRNAs) are newly recognised non-coding RNA (ncRNA) members characterised by tissue specificity, increased stability and enrichment within exosomes. Studies have shown that ionizing radiation (IR) can influence ncRNA transcription. However, it is unknown whether circRNAs or indeed QKI are regulated by IR. Microarray circRNA profiling and next generation sequencing revealed that circRNA expression was altered by low and medium dose exposure sourced predominantly from genes influencing the p53 pathway. CircRNAs KIRKOS-71 and KIRKOS-73 transcribed from the WWOX (WW Domain Containing Oxidoreductase) tumor suppressor (a p53 regulator) responded within hours to IR. KIRKOS-71 and KIRKOS-73 were present in exosomes yet exhibited differential transcript clearance between irradiated cell lines. Dual-quasar labelled probes and in-situ hybridization demonstrated the intercellular distribution of KIRKOS-71 and KIRKOS-73 predominantly within the perinucleus. QKI knockdown removed nuclear expression of these circRNAs with no significant effect on cytosolic KIRKOS-71 and KIRKOS-73. Distinct QKI transcription between cell lines and its augmented interaction with KIRKOS-71 and KIRKOS-73 was noted post IR. This foremost study provides evidence that QKI and circRNAs partake in the cellular irradiation response. KIRKOS-71 and KIRKOS-73 as stable secreted circRNAs may afford vital characteristics worth syphoning as promising diagnostic radiotherapy biomarkers.

12.
Sci Rep ; 7(1): 7163, 2017 08 02.
Article in English | MEDLINE | ID: mdl-28769061

ABSTRACT

The long non-coding RNA PARTICLE (Gene PARTICL- 'Promoter of MAT2A-Antisense RadiaTion Induced Circulating LncRNA) partakes in triple helix (triplex) formation, is transiently elevated following low dose irradiation and regulates transcription of its neighbouring gene - Methionine adenosyltransferase 2A. It now emerges that PARTICLE triplex sites are predicted in many different genes across all human chromosomes. In silico analysis identified additional regions for PARTICLE triplexes at >1600 genomic locations. Multiple PARTICLE triplexes are clustered predominantly within the human and mouse tumor suppressor WW Domain Containing Oxidoreductase (WWOX) gene. Surface plasmon resonance diffraction and electrophoretic mobility shift assays were consistent with PARTICLE triplex formation within human WWOX with high resolution imaging demonstrating its enrichment at this locus on chromosome 16. PARTICLE knockdown and over-expression resulted in inverse changes in WWOX transcripts levels with siRNA interference eliminating PARTICLEs elevated transcription to irradiation. The evidence for a second functional site of PARTICLE triplex formation at WWOX suggests that PARTICLE may form triplex-mediated interactions at multiple positions in the human genome including remote loci. These findings provide a mechanistic explanation for the ability of lncRNAs to regulate the expression of numerous genes distributed across the genome.


Subject(s)
Genome, Human , RNA, Long Noncoding/chemistry , RNA, Long Noncoding/genetics , Tumor Suppressor Proteins/genetics , WW Domain-Containing Oxidoreductase/genetics , Animals , Binding Sites , Cell Line, Tumor , Cell Survival , Chromosomes, Human, Pair 16 , Disease Susceptibility , Epistasis, Genetic , Gene Expression Regulation , Genetic Loci , Genome , Humans , MAP Kinase Signaling System , Mice , Nucleic Acid Conformation , Promoter Regions, Genetic , Protein Binding , RNA Interference , RNA, Small Interfering/genetics , Transcription, Genetic
13.
Cell Rep ; 11(3): 474-85, 2015 Apr 21.
Article in English | MEDLINE | ID: mdl-25900080

ABSTRACT

Exposure to low-dose irradiation causes transiently elevated expression of the long ncRNA PARTICLE (gene PARTICLE, promoter of MAT2A-antisense radiation-induced circulating lncRNA). PARTICLE affords both a cytosolic scaffold for the tumor suppressor methionine adenosyltransferase (MAT2A) and a nuclear genetic platform for transcriptional repression. In situ hybridization discloses that PARTICLE and MAT2A associate together following irradiation. Bromouridine tracing and presence in exosomes indicate intercellular transport, and this is supported by ex vivo data from radiotherapy-treated patients. Surface plasmon resonance indicates that PARTICLE forms a DNA-lncRNA triplex upstream of a MAT2A promoter CpG island. We show that PARTICLE represses MAT2A via methylation and demonstrate that the radiation-induced PARTICLE interacts with the transcription-repressive complex proteins G9a and SUZ12 (subunit of PRC2). The interplay of PARTICLE with MAT2A implicates this lncRNA in intercellular communication and as a recruitment platform for gene-silencing machineries through triplex formation in response to irradiation.


Subject(s)
DNA Methylation/radiation effects , Gene Expression Regulation/radiation effects , RNA, Long Noncoding/biosynthesis , RNA, Long Noncoding/genetics , Carcinoma, Squamous Cell/radiotherapy , Cell Line , Chromatin Immunoprecipitation , DNA Methylation/genetics , Electrophoretic Mobility Shift Assay , Head and Neck Neoplasms/radiotherapy , Humans , Immunoblotting , In Situ Hybridization , Methionine Adenosyltransferase/biosynthesis , Methionine Adenosyltransferase/genetics , Oligonucleotide Array Sequence Analysis , Radiation, Ionizing , Squamous Cell Carcinoma of Head and Neck , Surface Plasmon Resonance
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