Oxidative stress and predominant Abeta42(43) deposition in myopathies with rimmed vacuoles

Ultra-Orphan drug development for GNE Myopathy: A synthetic literature review and meta-analysis

GNE myopathy is an autosomal recessive hereditary muscle disorder that has the following clinical characteristics: develops in early adulthood, gradually progresses from the distal muscles, and is relatively sparing of quadriceps until the advanced stages of the disease. With further progression, patients become non-ambulatory and need a wheelchair. There is growing concern about extra-muscular presentations such as thrombocytopenia, respiratory dysfunction, and sleep apnea syndrome. Pathologically, rimmed vacuoles and tubulofilamentous inclusions are observed in affected muscles. The cause of the disease is thought to be a sialic acid deficiency due to mutations of the GNE gene required for in vivo sialic acid biosynthesis. Sialic acid supplementation to a presymptomatic GNE myopathy mouse model was effective in preventing the development of the disease. Several clinical studies have been conducted to evaluate the safety and efficacy of sialic acid supplementation in humans. Based on the favorable results of these studies, an extended-release aceneuramic acid formulation was approved for treatment of GNE myopathy in Japan in March 2024. It is anticipated that it will be a significant step in the development of an effective treatment for GNE myopathy and other ultra-orphan diseases.

Comparative Analysis of the Therapeutic Effects of MSCs From Umbilical Cord, Bone Marrow, and Adipose Tissue and Investigating the Impact of Oxidized RNA on Radiation-Induced Lung Injury

Radiation-induced lung injury (RILI) is frequently observed in patients undergoing radiotherapy for thoracic malignancies, constituting a significant complication that hampers the effectiveness and utilization of tumor treatments. Ionizing radiation exerts both direct and indirect detrimental effects on cellular macromolecules, including DNA, RNA and proteins, but the impact of oxidized RNA in RILI remains inadequately explored. Mesenchymal stem cells (MSCs) can repair injured tissues, and the reparative potential and molecular mechanism of MSCs in treating RILI remains incompletely understood. This study aimed to investigate the therapeutic effects and mechanisms of action of three distinct sources of MSCs, including human umbilical cord mesenchymal stem cells (UCMSCs), bone marrow mesenchymal stem cells (BMSCs), and adipose-derived stem cells (ADSCs), in thoracically irradiated mice. Comparative analysis revealed that all three types of MSCs exhibited the ability to mitigate radiation-induced inflammatory infiltration, alveolar hemorrhage, and alveolar wall thickening in the lung tissue of the mice. MSCs also attenuated RILI by decreasing inflammatory factors, upregulating anti-inflammatory factor expression, and reducing collagen accumulation. Immunohistochemical results showed that all three MSCs reduced radiation-induced cell apoptosis and promoted the regeneration of lung tissue cells. The analysis of malondialdehyde (MDA) and 8-hydroyguanosine (8-OHG) content indicated that MSCs possess reparative properties against radiation-induced oxidative damage in lung tissue. The study provides evidence that UCMSCs are a more appropriate therapeutic option for RILI compared to BMSCs and ADSCs. Additionally, MSCs effectively reduce the accumulation of oxidized RNA in RILI, thereby, presenting a unique avenue for investigating the underlying mechanism of MSC-based treatment for RILI.

Mutation in GNE Downregulates Peroxiredoxin IV Altering ER Redox Homeostasis

GNE myopathy is a rare neuromuscular genetic disorder characterized by early adult onset and muscle weakness due to mutation in sialic acid biosynthetic enzyme, UDP-N-acetylglucosamine 2-epimerase/N-acetylmannosamine kinase (GNE). More than 180 different GNE mutations are known all over the world with unclear pathomechanism. Although hyposialylation of glycoproteins is speculated to be the major cause, but cellular mechanism leading to loss of muscle mass has not yet been deciphered. Besides sialic acid biosynthesis, GNE affects other cellular functions such as cell adhesion and apoptosis. In order to understand the effect of mutant GNE protein on cellular functions, differential proteome profile of HEK293 cells overexpressing pathologically relevant recombinant mutant GNE protein (D207V and V603L) was analyzed. These cells, along with vector control and wild-type GNE-overexpressing cells, were subjected to two-dimensional gel electrophoresis coupled with mass spectrometry (MALDI-TOF/TOF MS/MS). In the study, 10 differentially expressed proteins were identified. Progenesis same spots software revealed downregulation of peroxiredoxin IV (PrdxIV), an ER-resident H₂O₂ sensor that regulates neurogenesis. Significant reduction in mRNA and protein levels of PrdxIV was observed in GNE mutant cell lines compared with vector control. However, neither total reactive oxygen species was altered nor H₂O₂ accumulation was observed in GNE mutant cell lines. Interestingly, ER redox state was significantly affected due to reduced normal GNE enzyme activity. Our study indicates that downregulation of PrdxIV affects ER redox state that may contribute to misfolding and aggregation of proteins in GNE myopathy.

Short-lived recombinant adeno-associated virus transgene expression in dystrophic muscle is associated with oxidative damage to transgene mRNA

Preclinical gene therapy strategies using recombinant adeno-associated virus (AAV) vectors in animal models of Duchenne muscular dystrophy have shown dramatic phenotype improvements, but long-lasting efficacy remains questionable. It is believed that in dystrophic muscles, transgene persistence is hampered, notably by the progressive loss of therapeutic vector genomes resulting from muscle fibers degeneration. Intracellular metabolic perturbations resulting from dystrophin deficiency could also be additional factors impacting on rAAV genomes and transgene mRNA molecular fate. In this study, we showed that rAAV genome loss is not the only cause of reduced transgene mRNA level and we assessed the contribution of transcriptional and post-transcriptional factors. We ruled out the implication of transgene silencing by epigenetic mechanisms and demonstrated that rAAV inhibition occurred mostly at the post-transcriptional level. Since Duchenne muscular dystrophy (DMD) physiopathology involves an elevated oxidative stress, we hypothesized that in dystrophic muscles, transgene mRNA could be damaged by oxidative stress. In the mouse and dog dystrophic models, we found that rAAV-derived mRNA oxidation was increased. Interestingly, when a high expression level of a therapeutic transgene is achieved, oxidation is less pronounced. These findings provide new insights into rAAV transductions in dystrophic muscles, which ultimately may help in the design of more effective clinical trials.

Free radicals: properties, sources, targets, and their implication in various diseases

Free radicals and other oxidants have gained importance in the field of biology due to their central role in various physiological conditions as well as their implication in a diverse range of diseases. The free radicals, both the reactive oxygen species (ROS) and reactive nitrogen species (RNS), are derived from both endogenous sources (mitochondria, peroxisomes, endoplasmic reticulum, phagocytic cells etc.) and exogenous sources (pollution, alcohol, tobacco smoke, heavy metals, transition metals, industrial solvents, pesticides, certain drugs like halothane, paracetamol, and radiation). Free radicals can adversely affect various important classes of biological molecules such as nucleic acids, lipids, and proteins, thereby altering the normal redox status leading to increased oxidative stress. The free radicals induced oxidative stress has been reported to be involved in several diseased conditions such as diabetes mellitus, neurodegenerative disorders (Parkinson's disease-PD, Alzheimer's disease-AD and Multiple sclerosis-MS), cardiovascular diseases (atherosclerosis and hypertension), respiratory diseases (asthma), cataract development, rheumatoid arthritis and in various cancers (colorectal, prostate, breast, lung, bladder cancers). This review deals with chemistry, formation and sources, and molecular targets of free radicals and it provides a brief overview on the pathogenesis of various diseased conditions caused by ROS/RNS.

Determination of Intracellular Levels of Reactive Oxygen Species Using the 2,7-dichlorofluorescein Diacetate Assay by Kinetic Monte Carlo Simulation

Reactive oxygen species (ROS) are reactive molecules which are produced normally by metabolic reactions. 2,7-Dichlorofluorescein diacetate (DCHF-DA) assay is used to determine intracellular levels of ROS in cancer cells. In the present study, the mechanism and kinetic parameters of this determination are obtained by kinetic Monte Carlo simulation. The values of the rate constants for the suggested mechanism were obtained by simulation. Then, the effect of DCHF-DA concentration on the rate of reaction was studied. According to the results, the product concentration should increase on increasing the DCHF-DA concentration. In addition, the effect of ROS concentration on the rate of reaction was determined.

Exploring the role of genetic variability and lifestyle in oxidative stress response for healthy aging and longevity

Oxidative stress is both the cause and consequence of impaired functional homeostasis characterizing human aging. The worsening efficiency of stress response with age represents a health risk and leads to the onset and accrual of major age-related diseases. In contrast, centenarians seem to have evolved conservative stress response mechanisms, probably derived from a combination of a diet rich in natural antioxidants, an active lifestyle and a favorable genetic background, particularly rich in genetic variants able to counteract the stress overload at the level of both nuclear and mitochondrial DNA. The integration of these factors could allow centenarians to maintain moderate levels of free radicals that exert beneficial signaling and modulator effects on cellular metabolism. Considering the hot debate on the efficacy of antioxidant supplementation in promoting healthy aging, in this review we gathered the existing information regarding genetic variability and lifestyle factors which potentially modulate the stress response at old age. Evidence reported here suggests that the integration of lifestyle factors (moderate physical activity and healthy nutrition) and genetic background could shift the balance in favor of the antioxidant cellular machinery by activating appropriate defense mechanisms in response to exceeding external and internal stress levels, and thus possibly achieving the prospect of living a longer life.

Cell stress molecules in the skeletal muscle of GNE myopathy

Background

Mutations of the UDP-N-acetylglucosamine-2-epimerase/N-acetylmannosamine-kinase (GNE)-gene are causally related to GNE myopathy. Yet, underlying pathomechanisms of muscle fibre damage have remained elusive. In sporadic inclusion body myositis (sIBM), the pro-inflammatory cell-stress mediators αB-crystallin and inducible nitric oxide synthase (iNOS) are crucial markers of the disease pathology.

Methods

10 muscle biopsies from GNE myopathy patients were analyzed for mRNA-expression of markers of cell-stress, inflammation and β-amyloid and compared to non-myopathic controls. Using double-labeling immunohistochemistry, serial sections of skeletal muscle biopsies were stained for amyloid precursor protein (APP), major histocompatibility complex (MHC)-I, αB-crystallin, neural cell adhesion molecule (NCAM), interleukin (IL)-1β, β-amyloid, iNOS, and phosphorylated neurofilament (P-neurofilament) as well as hematoxylin/eosin histochemistry. Corresponding areas of all biopsies with a total of 2,817 muscle fibres were quantitatively assessed for all markers.

Results

mRNA-expression of APP, NCAM, iNOS, TNF-α and TGF-β was higher in GNE myopathy compared to controls, yet this was not statistically significant. The mRNA-expression of APP and αB-crystallin significantly correlated with the expression of several pro-inflammatory and cell-stress-associated markers as NCAM, IL-1β, TGF-β, CCL-3, and CCL4. By immunohistochemistry, αB-crystallin and iNOS were co-upregulated and the number of fibres positive for αB-crystallin, NCAM, MHC-I and iNOS significantly correlated with each other. A large fraction of fibres positive for αB-crystallin were double positive for iNOS and vice-versa. Moreover, several fibres with structural abnormalities were positive for αB-crystallin and iNOS. Notably, particularly normal appearing fibres displayed an overexpression of these molecules.

Conclusions

The cell-stress molecules αB-crystallin and iNOS are overexpressed in GNE myopathy muscle and may identify early disease mechanisms. The data help to better understand the pathology of GNE myopathy.

Markers of oxidant stress that are clinically relevant in aging and age-related disease

Despite the long held hypothesis that oxidant stress results in accumulated oxidative damage to cellular macromolecules and subsequently to aging and age-related chronic disease, it has been difficult to consistently define and specifically identify markers of oxidant stress that are consistently and directly linked to age and disease status. Inflammation because it is also linked to oxidant stress, aging, and chronic disease also plays an important role in understanding the clinical implications of oxidant stress and relevant markers. Much attention has focused on identifying specific markers of oxidative stress and inflammation that could be measured in easily accessible tissues and fluids (lymphocytes, plasma, serum). The purpose of this review is to discuss markers of oxidant stress used in the field as biomarkers of aging and age-related diseases, highlighting differences observed by race when data is available. We highlight DNA, RNA, protein, and lipid oxidation as measures of oxidative stress, as well as other well-characterized markers of oxidative damage and inflammation and discuss their strengths and limitations. We present the current state of the literature reporting use of these markers in studies of human cohorts in relation to age and age-related disease and also with a special emphasis on differences observed by race when relevant.

Characterization of RNA damage under oxidative stress in Escherichia coli

We have examined the level of 8-hydroxyguanosine (8-oxo-G), an oxidized form of guanosine, in RNA in Escherichia coli under normal and oxidative stress conditions. The level of 8-oxo-G in RNA rises rapidly and remains high for hours in response to hydrogen peroxide (H₂O₂) challenge in a dose-dependent manner. H₂O₂ induced elevation of 8-oxo-G content is much higher in RNA than that of 8-hydroxydeoxyguanosine (8-oxo-dG) in DNA. Under normal conditions, the 8-oxo-G level is low in RNA isolated from the ribosome and it is nearly three times higher in non-ribosomal RNAs. In contrast, 8-oxo-G generated by a short exposure to H₂O₂ is almost equally distributed in various RNA species, suggesting that although ribosomal RNAs are normally less oxidized, they are not protected against exogenous H₂O₂. Interestingly, highly folded RNA is not protected from oxidation because 8-oxo-G generated by H₂O₂ treatment in vitro increases to approximately the same levels in tRNA and rRNA in both native and denatured forms. Lastly, increased RNA oxidation is closely associated with cell death by oxidative stress. Our data suggests that RNA is a primary target for reactive oxygen species and RNA oxidation is part of the paradox that cells have to deal with under oxidative stress.

Nitric oxide stress in sporadic inclusion body myositis muscle fibres: inhibition of inducible nitric oxide synthase prevents interleukin-1β-induced accumulation of β-amyloid and cell death

Sporadic inclusion body myositis is a severely disabling myopathy. The design of effective treatment strategies is hampered by insufficient understanding of the complex disease pathology. Particularly, the nature of interrelationships between inflammatory and degenerative pathomechanisms in sporadic inclusion body myositis has remained elusive. In Alzheimer's dementia, accumulation of β-amyloid has been shown to be associated with upregulation of nitric oxide. Using quantitative polymerase chain reaction, an overexpression of inducible nitric oxide synthase was observed in five out of ten patients with sporadic inclusion body myositis, two of eleven with dermatomyositis, three of eight with polymyositis, two of nine with muscular dystrophy and two of ten non-myopathic controls. Immunohistochemistry confirmed protein expression of inducible nitric oxide synthase and demonstrated intracellular nitration of tyrosine, an indicator for intra-fibre production of nitric oxide, in sporadic inclusion body myositis muscle samples, but much less in dermatomyositis or polymyositis, hardly in dystrophic muscle and not in non-myopathic controls. Using fluorescent double-labelling immunohistochemistry, a significant co-localization was observed in sporadic inclusion body myositis muscle between β-amyloid, thioflavine-S and nitrotyrosine. In primary cultures of human myotubes and in myoblasts, exposure to interleukin-1β in combination with interferon-γ induced a robust upregulation of inducible nitric oxide synthase messenger RNA. Using fluorescent detectors of reactive oxygen species and nitric oxide, dichlorofluorescein and diaminofluorescein, respectively, flow cytometry revealed that interleukin-1β combined with interferon-γ induced intracellular production of nitric oxide, which was associated with necrotic cell death in muscle cells. Intracellular nitration of tyrosine was noted, which partly co-localized with amyloid precursor protein, but not with desmin. Pharmacological inhibition of inducible nitric oxide synthase by 1400W reduced intracellular production of nitric oxide and prevented accumulation of β-amyloid, nitration of tyrosine as well as cell death inflicted by interleukin-1β combined with interferon-γ. Collectively, these data suggest that, in skeletal muscle, inducible nitric oxide synthase is a central component of interactions between interleukin-1β and β-amyloid, two of the most relevant molecules in sporadic inclusion body myositis. The data further our understanding of the pathology of sporadic inclusion body myositis and may point to novel treatment strategies.

Oxidative damage to RNA: mechanisms, consequences, and diseases

Overproduction of free radicals can damage cellular components resulting in progressive physiological dysfunction, which has been implicated in many human diseases. Oxidative damage to RNA received little attention until the past decade. Recent studies indicate that RNA, such as messenger RNA and ribosomal RNA, is very vulnerable to oxidative damage. RNA oxidation is not a consequence of dying cells but an early event involved in pathogenesis. Oxidative modification to RNA results in disturbance of the translational process and impairment of protein synthesis, which can cause cell deterioration or even cell death. In this review, we discuss the mechanisms of oxidative damage to RNA and the possible biological consequences of damaged RNA. Furthermore, we review recent evidence suggesting that oxidative damage to RNA may contribute to progression of many human diseases.

RNA oxidation in Alzheimer disease and related neurodegenerative disorders

RNA oxidation and its biological effects are less well studied compared to DNA oxidation. However, RNA may be more susceptible to oxidative insults than DNA, for RNA is largely single-stranded and its bases are not protected by hydrogen bonding and less protected by specific proteins. Also, cellular RNA locates in the vicinity of mitochondria, the primary source of reactive oxygen species. Oxidative modification can occur not only in protein-coding RNAs, but also in non-coding RNAs that have been recently revealed to contribute towards the complexity of the mammalian brain. Damage to coding and non-coding RNAs will cause errors in proteins and disturbances in the regulation of gene expression. While less lethal than mutations in the genome and not inheritable, such sublethal damage to cells might be associated with underlying mechanisms of degeneration, especially age-associated neurodegeneration that is commonly found in the elderly population. Indeed, oxidative RNA damage has been described recently in most of the common neurodegenerative disorders including Alzheimer disease, Parkinson disease, dementia with Lewy bodies and amyotrophic lateral sclerosis. Of particular interest, the accumulating evidence obtained from studies on either human samples or experimental models coincidentally suggests that oxidative RNA damage is a feature in vulnerable neurons at early-stage of these neurodegenerative disorders, indicating that RNA oxidation actively contributes to the onset or the development of the disorders. Further investigations aimed at understanding of the processing mechanisms related to oxidative RNA damage and its consequences may provide significant insights into the pathogenesis of neurodegenerative disorders and lead to better therapeutic strategies.

In inclusion-body myositis muscle fibers Parkinson-associated DJ-1 is increased and oxidized

Sporadic inclusion-body myositis (s-IBM) is the most common muscle disease of older persons. The muscle-fiber molecular phenotype exhibits similarities to both Alzheimer-disease (AD) and Parkinson-disease (PD) brains, including accumulations of amyloid-beta, phosphorylated tau, alpha-synuclein, and parkin, as well as evidence of oxidative stress and mitochondrial abnormalities. Early-onset autosomal-recessive PD can be caused by mutations in the DJ-1 gene, leading to its inactivation. DJ-1 has antioxidative and mitochondrial-protective properties. In AD and PD brains, DJ-1 is increased and oxidized. We studied DJ-1 in 17 s-IBM and 18 disease-control and normal muscle biopsies by: (1) immunoblots of muscle homogenates and mitochondrial fractions; (2) real-time PCR; (3) oxyblots evaluating DJ-1 oxidation; (4) light- and electron-microscopic immunocytochemistry. Compared to controls, in s-IBM muscle fibers DJ-1 was: (a) increased in the soluble fraction, monomer 2-fold (P = 0.01), and dimer 2.8-fold (P = 0.004); (b) increased in the mitochondrial fraction; (c) highly oxidized; and (d) aggregated in about 15% of the abnormal muscle fibers. DJ-1 mRNA was increased 3.5-fold (P = 0.034). Accordingly, DJ-1 might play a role in human muscle disease, and thus not be limited to human CNS degenerations. In s-IBM muscle fibers, DJ-1 could be protecting these fibers against oxidative stress, including protection of mitochondria.

Sublethal RNA oxidation as a mechanism for neurodegenerative disease

Although cellular RNA is subjected to the same oxidative insults as DNA and other cellular macromolecules, oxidative damage to RNA has not been a major focus in investigations of the biological consequences of free radical damage. In fact, because it is largely single-stranded and its bases lack the protection of hydrogen bonding and binding by specific proteins, RNA may be more susceptible to oxidative insults than is DNA. Oxidative damage to protein-coding RNA or non-coding RNA will, in turn, potentially cause errors in proteins and/or dysregulation of gene expression. While less lethal than mutations in the genome, such sublethal insults to cells might be associated with underlying mechanisms of several chronic diseases, including neurodegenerative disease. Recently, oxidative RNA damage has been described in several neurodegenerative diseases including Alzheimer disease, Parkinson disease, dementia with Lewy bodies, and prion diseases. Of particular interest, oxidative RNA damage can be demonstrated in vulnerable neurons early in disease, suggesting that RNA oxidation may actively contribute to the onset of the disease. An increasing body of evidence suggests that, mechanistically speaking, the detrimental effects of oxidative RNA damage to protein synthesis are attenuated, at least in part, by the existence of protective mechanisms that prevent the incorporation of the damaged ribonucleotides into the translational machinery. Further investigations aimed at understanding the processing mechanisms related to oxidative RNA damage and its consequences may provide significant insights into the pathogenesis of neurodegenerative and other degenerative diseases and lead to better therapeutic strategies.

Desmin is oxidized and nitrated in affected muscles in myotilinopathies and desminopathies

Degenerative diseases with abnormal protein aggregates are characterized by the accumulation of proteins with variable posttranslational modifications including phosphorylation, glycoxidation, oxidation, and nitration. Myofibrillar myopathies, including myotilinopathies and desminopathies, are characterized by the intracytoplasmic focal accumulation of proteins in insoluble aggregates in muscle cells. By using single immunohistochemistry, monodimensional gel electrophoresis and Western blotting, and bidimensional gel electrophoresis, in-gel digestion, and mass spectometry, desmin was demonstrated to be a major target of oxidation and nitration in both desminopathies and myotilinopathies. Because oxidized and nitrated proteins may have toxic effects and may impair ubiquitin-proteasomal function, modified desmin can be considered to be an additional element in the pathogenesis of myofibrillar myopathies. In addition to desmin, pyruvate kinase muscle splice form M1 is oxidized, thus supporting complemental mitochondrial damage, at least in some cases of myotilinopathy.

Inclusion body myositis: current pathogenetic concepts and diagnostic and therapeutic approaches

Inclusion body myositis is the most common acquired muscle disease in older individuals, and its prevalence varies among countries and ethnic groups. The aetiology and pathogenesis of sporadic inclusion body myositis are still poorly understood; however genetic factors, ageing, and environmental triggers might all have a role. Unlike other inflammatory myopathies, sporadic inclusion body myositis causes slowly progressing muscular weakness and atrophy, it has a distinctive pattern of muscle involvement, and is unresponsive to conventional forms of immunotherapy. This review covers the clinical presentation, diagnosis, treatment, and the latest information on genetic susceptibility and pathogenesis of sporadic inclusion body myositis.

RNA damage and surveillance under oxidative stress

RNA damage has been recently reported to increase under oxidative stress and in patients with many degenerative diseases, which has drawn attention to the consequences of RNA oxidation at the molecular and cellular levels. Under similar conditions the levels of oxidative damage in RNA are usually higher than those in DNA, which may impair protein synthesis or other RNA function. Therefore, accumulation of RNA damage must be prevented and cells have developed specific mechanisms to remove oxidatively-damaged RNA and to block incorporation of oxidized nucleotides during RNA synthesis. Removal of oxidized RNA may be mediated by specific proteins that recognize oxidative lesions and direct the RNA degradation machinery to eliminate the damaged RNAs. During RNA synthesis, oxidized ribonucleotides are hydrolyzed or discriminated from normal ribonucleotides during transcription, preventing their incorporation into RNA. Collective evidence suggests that RNA oxidative damage is a challenging and persistent problem normally controlled through RNA surveillance mechanisms, making them critical to maintaining cellular health and preventing disease.

Quantification of RNA damage by reverse transcription polymerase chain reactions

RNA damages, such as those generated by nucleic acid-modifying agents, occur randomly in RNA and present challenging problems to organisms. It has been unclear how RNA function would be affected by many forms of RNA damage and how cells are protected against the damage. Elucidation of these mechanisms has been hampered by the lack of sensitive and efficient methodologies detecting damages randomly occurring in RNA, especially for the damage of a specific RNA. In this work, we have developed a method using reverse transcription polymerase chain reactions (RT-PCRs) to determine the level of damage of a specific RNA. The level of damage of the Escherichia coli 16S rRNA caused by oxidative stress was examined. When RNA is treated by H(2)O(2) in vitro, the normalized level of long cDNA is inversely dependent on the dosage of H(2)O(2) as determined by gel-based assay or real-time PCR. Long cDNA was also produced at reduced levels using RNA prepared from H(2)O(2)-treated E. coli cultures compared with RNA from control cultures. Remarkably, the level of cDNA reduction caused by H(2)O(2) treatment depends on the length of cDNA examined, suggesting random occurrences of damage in RNA templates. Approximately 40% of the reduction in cDNA can be detected in each kilobase of RNA from E. coli cultures treated with 0.5 mM H(2)O(2). This method is able to detect any type of damage in RNA-causing termination of reverse transcription and works on specific RNA of interest with high sensitivity.

Oxidative stress and electron spin resonance

The body constantly reacts with oxygen as part of the energy producing processes of cells. Oxidative stress is a dysbalance between the production of free radicals as products of these reactions and antioxidant properties of cells. The factors influencing the production of free radicals are physical agents, chemical agents and biological agents. Free radicals are paramagnetic molecules with short time-period for their detection by electron spin resonance (ESR) spectroscopy. The free radical stabilization can be gained by freezing a solution of an organic radical or bonding to spin trapping agents. The spin trapping agents are diamagnetic compounds which rapidly scavenge transient radicals to form stable paramagnetic spin adducts radicals. Because this secondary radical retains an unpaired electron, it can often be detected by electron spin resonance. From ESR spectra can be obtained structural information and kinetic information, information about the formation and decay of the radicals. To study the process of free radical generation is an important step towards reducing the deteriorating effects of oxidative stress.

Identification, design, synthesis, and pharmacological activity of (4-ethyl-piperazin-1-yl)-phenylmethanone derivatives with neuroprotective properties against beta-amyloid-induced toxicity

In search of novel therapeutic approaches for Alzheimer's disease (AD), we report herein the identification, design, synthesis, and pharmacological activity of (4-ethyl-piperaz-1-yl)-phenylmethanone derivatives with neuroprotective properties against beta-amyloid-induced toxicity. (4-ethyl-piperaz-1-yl)-phenylmethanone is a common substructure shared by molecules isolated from plants of the Asteraceae genus, traditionally used as restorative of lost or declining mental functions. (4-Ethyl-piperaz-1-yl)-phenylmethanone displayed strong neuroprotective properties against Abeta1-42 and reversed Abeta1-42-induced ATP depletion on neuronal cells, suggesting a mitochondrial site of action. Abeta1-42 has been described to induce a hyperactivity of the glutamate network in neuronal cells. (4-Ethyl-piperaz-1-yl)-phenylmethanone also inhibited the neurotoxic effect that glutamate displayed on PC12 cells, suggesting that the reduction of glutamate-induced neurotoxicity may be one of the mechanisms by which this compound exerts its neuroprotective properties against the deleterious effects of the Abeta1-42. These data suggest that the identified (4-ethyl-piperaz-1-yl)-phenylmethanone chemical entity exerts neuroprotective properties and may serve as a lead compound for the development of novel therapies for AD.

Overexpression of semicarbazide-sensitive amine oxidase in human myopathies

Oxidative stress has been implicated in the pathogenesis of several muscle diseases. Semicarbazide-sensitive amine oxidase (SSAO) metabolizes oxidative deamination of primary aromatic and aliphatic amines. In the oxidative reactions, amine substrates are converted into the aldehyde, followed by the production of ammonia and H(2)O(2). Although normal levels in muscle are very low, SSAO is expressed in almost all mammalian tissues. In this study, we examined the possible implication of SSAO as an additional source of oxidative stress in the pathogenesis of muscle disorders. The expression of SSAO was examined immunohistochemically in muscle biopsy specimens from patients with inclusion-body myositis (IBM; n = 5), desmin-related myopathy (DRM; n = 3), dermatomyositis (n = 3), granulomatous (sarcoid) myopathy (n = 2), muscle denervation-reinnervation (n = 3), and rhabdomyolysis (n = 2), as well as from control subjects (n = 3). Strong SSAO immunoreactivity was present in vacuolated and nonvacuolated fibers in IBM, in abnormal fibers in DRM, and in degenerating and regenerating fibers in dermatomyositis and rhabdomyolysis. In addition, SSAO overexpression was observed in muscle fibers adjacent to granulomas in sarcoid myopathy. These results suggest that SSAO is a source of oxidative stress in diseased human skeletal muscle and that it contributes to oxidative stress-induced damage in various inflammatory and other myopathies. Alternatively, the expression of SSAO in muscle fibers may be a consequence of muscle fiber injury.