Publications by authors named "Naveen Kumar Singhal"

RNA oxidation has been implicated in neurodegeneration, but the underlying mechanism for such effects is unclear. Extensive RNA oxidation occurs within the neurons in multiple sclerosis (MS) brains. Here, we identified selectively oxidized mRNAs in neuronal cells that pertained to neuropathological pathways.

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Chronic activation of B-cell receptor (BCR) signaling via Bruton tyrosine kinase (BTK) is largely considered to be one of the primary mechanisms driving disease progression in B-Cell lymphomas. Although the BTK-targeting agent ibrutinib has shown promising clinical responses, the presence of primary or acquired resistance is common and often leads to dismal clinical outcomes. Resistance to ibrutinib therapy can be mediated through genetic mutations, up-regulation of alternative survival pathways, or other unknown factors that are not targeted by ibrutinib therapy.

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Unlabelled: Mitochondrial changes, including decreased expression of electron transport chain subunit genes and impaired energetic, have been reported in multiple sclerosis (MS), but the mechanisms involved in these changes are not clear. To determine whether epigenetic mechanisms are involved, we measured the concentrations of methionine metabolites by liquid chromatography tandem mass spectrometry, histone H3 methylation patterns, and markers of mitochondrial respiration in gray matter from postmortem MS and control cortical samples. We found decreases in respiratory markers as well as decreased concentrations of the methionine metabolites S-adenosylmethionine, betaine, and cystathionine in MS gray matter.

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The study aimed to measure the neuroprotective efficacy of caffeine-encapsulated poly(lactic-co-glycolic acid) (PLGA) nanoparticles over bulk and to delineate the mechanism of improvement in efficacy both in vitro and in 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine (MPTP)-induced mouse model of Parkinsonism. Caffeine-encapsulated PLGA nanoparticles exhibited more pronounced increase in the endurance of dopaminergic neurons, fibre outgrowth and expression of tyrosine hydroxylase (TH) and growth-associated protein-43 (GAP-43) against 1-methyl-4-phenylpyridinium (MPP+)-induced alterations in vitro. Caffeine-encapsulated PLGA nanoparticles also inhibited MPP(+)-mediated nuclear translocation of nuclear factor-kappa B (NF-κB) and augmented protein kinase B phosphorylation more potentially than bulk counterpart.

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Parkinson's disease (PD) is the second most unconcealed neurodegenerative disorder labelled with motor impairments. Two pesticides, manganese ethylene-1,2-bisdithiocarbamate (maneb) and 1,1'-dimethyl-4,4'-bipyridinium dichloride (paraquat), together, are reported to increase the incidence of PD in humans and Parkinsonism in mice. Conversely, silymarin and melatonin, two naturally occurring antioxidants, rescue from maneb- and paraquat-induced Parkinsonism.

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For some instances of Parkinson disease (PD), current evidence in the literature is consistent with reactive oxygen species being involved in the etiology of the disease. The management of PD is still challenging owing to its ambiguous etiology and lack of permanent cure. Because nicotine offers neuroprotection against 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine-induced parkinsonism, the neuroprotective efficacy of nicotine-encapsulated poly(lactic-co-glycolic) acid (PLGA) nanoparticles and the underlying mechanism of improved efficacy, if any, over bulk nicotine were assessed in this study.

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Nitric oxide (NO) is an important inorganic molecule of the biological system owing to diverse physiological implications. NO is synthesised from a semi-essential amino acid L-arginine. NO biosynthesis is catalysed by a family of enzymes referred to as nitric oxide synthases (NOSs).

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Parkinson's disease (PD), a neurodegenerative disorder, is characterized by the selective degeneration of the nigrostriatal dopaminergic neurons, continuing or permanent deficiency of dopamine, accretion of an abnormal form of alpha synuclein in the adjacent neurons, and dysregulation of ubiquitin proteasomal system, mitochondrial metabolism, permeability and integrity, and cellular apoptosis resulting in rigidity, bradykinesia, resting tremor, and postural instability. Melatonin, an indoleamine produced almost in all the organisms, has anti-inflammatory, anti-apoptotic, and anti-oxidant nature. Experimental studies employing 1-methyl 4-phenyl 1, 2, 3, 6-tetrahydropyridine (MPTP), 6-hydroxydopamine (6-OHDA), methamphetamine, rotenone, and maneb and paraquat models have shown an enormous potential of melatonin in amelioration of the symptomatic features of PD.

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Oxidative stress is reported as one of the most widely accepted mechanisms of maneb (MB)- and paraquat (PQ)-induced nigrostriatal dopaminergic neurodegeneration leading to the Parkinson's disease (PD) phenotype. The study investigated the effects of silymarin, an antioxidant of plant origin, and melatonin, an indoleamine produced in all species, in MB- and PQ-induced mouse model of PD. The mice were treated intraperitoneally daily with silymarin (40mg/kg) or melatonin (30mg/kg) along with respective controls for 9wk.

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Exposure to 1-methyl 4-phenyl 1,2,3,6-tetrahydropyridine (MPTP) induces dopaminergic neurodegeneration in the nigrostriatal pathway and nicotine and caffeine ameliorate neurodegenerative changes in MPTP-lesioned mouse model of Parkinson's disease (PD). The present study was undertaken to investigate the effect of nicotine and caffeine on the expression patterns of genes in the striatum of control and MPTP-treated mice to identify the differentially expressed transcripts and to assess their possible implications in neuroprotection. Mice were treated intraperitoneally with caffeine (20mg/kg) or nicotine (1mg/kg), daily, for the first 8 weeks followed by MPTP (20mg/kg) co-treatment for further 4 weeks along with respective controls.

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High-throughput omics strategies delineate the molecular mechanism of toxicity, predict the toxicity of newer drugs and chemicals, and identify individuals at high risks on the basis of expression patterns of messenger ribonucleic acids, genes, and proteins, and detection of intermediary metabolites. Despite being a developing country, India is one of the fastest growing nations in the usages and applications of omics technologies. Several differentially expressed genes and proteins under various pathological and toxicant-exposed conditions have been identified, and many association studies on genetic polymorphisms with toxicant-induced diseases have been conducted for the predictive and mechanistic purposes.

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Cytochrome P450 1B1 (CYP1B1) and catechol-O-methyltransferase (COMT) enzymes play critical roles in estrogen metabolism. Alterations in the catalytic activity of CYP1B1 and COMT enzymes have been found associated with altered breast cancer risk in postmenopausal women in many populations. The substitution of leucine (Leu) to valine (Val) at codon 432 increases the catalytic activity of CYP1B1, however, substitution of Val to methionine (Met) at codon 158 decreases the catalytic activity of COMT.

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