Identification of differentially expressed proteins in striatum of maneb-and paraquat-induced Parkinson's disease phenotype in mouse

Lead and copper in hunted wild boars and radiographic evaluation of bullet fragmentation between ammunitions

The purpose of the present study was to evaluate the content of lead in carcasses of wild boars shot with lead bullets, in comparison with that of copper caused by lead-free ammunitions. Radiographic images of hunted boars were obtained in order to assess the degree of bullet fragmentation in the carcasses. Samples of meat were collected from different body areas at increasing distance from bullet trajectory, to be analysed by ICP-MS for lead and copper levels. In wild boars shot with lead ammunitions, a massive dispersion of bullet fragments and very high lead levels were detected. By contrast, in wild boars killed with copper ammunitions no radiographic signs of bullet fragmentation were observed. Copper ammunitions seem therefore a safer alternative to standard lead-core ones, due to their minimal fragmentation and the relatively low toxicity of this metal.

Glia maturation factor-β: a potential therapeutic target in neurodegeneration and neuroinflammation

Glia maturation factor-β (GMFB) is considered to be a growth and differentiation factor for both glia and neurons. GMFB has been found to be upregulated in several neuroinflammation and neurodegeneration conditions. It may function by mediating apoptosis and by modulating the expression of superoxide dismutase, granulocyte-macrophage colony-stimulating factor, and neurotrophin. In this review, we mainly discussed the role of GMFB in several neuroinflammatory and neurodegenerative diseases. On review of the literature, we propose that GMFB may be a promising therapeutic target for neuroinflammatory and neurodegenerative diseases.

Differential proteome profiling in the hippocampus of amnesic mice

Amnesia or memory loss is associated with brain aging and several neurodegenerative pathologies including Alzheimer's disease (AD). This can be induced by a cholinergic antagonist scopolamine but the underlying molecular mechanism is poorly understood. This study of proteome profiling in the hippocampus could provide conceptual insights into the molecular mechanisms involved in amnesia. To reveal this, mice were administered scopolamine to induce amnesia and memory impairment was validated by novel object recognition test. Using two-dimensional gel electrophoresis coupled with MALDI-MS/MS, we have analyzed the hippocampal proteome and identified 18 proteins which were differentially expressed. Out of these proteins, 11 were downregulated and 7 were upregulated in scopolamine-treated mice as compared to control. In silico analysis showed that the majority of identified proteins are involved in metabolism, catalytic activity, and cytoskeleton architectural functions. STRING interaction network analysis revealed that majority of identified proteins exhibit common association with Actg1 cytoskeleton and Vdac1 energy transporter protein. Furthermore, interaction map analysis showed that Fascin1 and Coronin 1b individually interact with Actg1 and regulate the actin filament dynamics. Vdac1 was significantly downregulated in amnesic mice and showed interaction with other proteins in interaction network. Therefore, we silenced Vdac1 in the hippocampus of normal young mice and found similar impairment in recognition memory of Vdac1 silenced and scopolamine-treated mice. Thus, these findings suggest that Vdac1-mediated disruption of energy metabolism and cytoskeleton architecture might be involved in scopolamine-induced amnesia.

Approaches for targeted proteomics and its potential applications in neuroscience

An extensive guide on practicable and significant quantitative proteomic approaches in neuroscience research is important not only because of the existing overwhelming limitations but also for gaining valuable understanding into brain function and deciphering proteomics from the workbench to the bedside. Early methodologies to understand the functioning of biological systems are now improving with high-throughput technologies, which allow analysis of various samples concurrently, or of thousand of analytes in a particular sample. Quantitative proteomic approaches include both gel-based and non-gel-based methods that can be further divided into different labelling approaches. This review will emphasize the role of existing technologies, their advantages and disadvantages, as well as their applications in neuroscience. This review will also discuss advanced approaches for targeted proteomics using isotope-coded affinity tag (ICAT) coupled with laser capture microdissection (LCM) followed by liquid chromatography tandem mass spectrometric (LC-MS/MS) analysis. This technology can further be extended to single cell proteomics in other areas of biological sciences and can be combined with other 'omics' approaches to reveal the mechanism of a cellular alterations. This approach may lead to further investigation in basic biology, disease analysis and surveillance, as well as drug discovery. Although numerous challenges still exist, we are confident that this approach will increase the understanding of pathological mechanisms involved in neuroendocrinology, neuropsychiatric and neurodegenerative disorders by delivering protein biomarker signatures for brain dysfunction.

Oxidative Stress Triggers Body-Wide Skipping of Multiple Exons of the Spinal Muscular Atrophy Gene

Humans carry two nearly identical copies of Survival Motor Neuron gene: SMN1 and SMN2. Loss of SMN1 leads to spinal muscular atrophy (SMA), the most frequent genetic cause of infant mortality. While SMN2 cannot compensate for the loss of SMN1 due to predominant skipping of exon 7, correction of SMN2 exon 7 splicing holds the promise of a cure for SMA. Previously, we used cell-based models coupled with a multi-exon-skipping detection assay (MESDA) to demonstrate the vulnerability of SMN2 exons to aberrant splicing under the conditions of oxidative stress (OS). Here we employ a transgenic mouse model and MESDA to examine the OS-induced splicing regulation of SMN2 exons. We induced OS using paraquat that is known to trigger production of reactive oxygen species and cause mitochondrial dysfunction. We show an overwhelming co-skipping of SMN2 exon 5 and exon 7 under OS in all tissues except testis. We also show that OS increases skipping of SMN2 exon 3 in all tissues except testis. We uncover several new SMN2 splice isoforms expressed at elevated levels under the conditions of OS. We analyze cis-elements and transacting factors to demonstrate the diversity of mechanisms for splicing misregulation under OS. Our results of proteome analysis reveal downregulation of hnRNP H as one of the potential consequences of OS in brain. Our findings suggest SMN2 as a sensor of OS with implications to SMA and other diseases impacted by low levels of SMN protein.

Pulmonary Proteome and Protein Networks in Response to the Herbicide Paraquat in Rats

Paraquat (PQ) has been one of the most widely used herbicides in the world. PQ, when ingested, is toxic to humans and may cause acute respiratory distress syndrome. To investigate molecular perturbation in lung tissues caused by PQ, Sprague Dawley male rats were fed with PQ at a dose of 25 mg/kg body weight for 20 times in four weeks. The effects of PQ on cellular processes and biological pathways were investigated by analyzing proteome in the lung tissues in comparison with the control. Among the detected proteins, 321 and 254 proteins were over-represented and under-represented, respectively, in the PQ-exposed rat lung tissues in comparison with the no PQ control. All over- and under-represented proteins were subjected to Ingenuity Pathway Analysis to create 25 biological networks and 38 pathways of interacting protein clusters. Over-represented proteins were involved in the C-jun-amino-terminal kinase pathway, caveolae-mediated endocytosis signaling, cardiovascular-cancer-respiratory pathway, regulation of clathrin-mediated endocytosis, non-small cell lung cancer signaling, pulmonary hypertension, glutamate receptor, immune response and angiogenesis. Under-represented proteins occurred in the p53 signaling pathway, mitogen-activated protein kinase signaling pathway, cartilage development and angiogenesis inhibition in the PQ-treated lungs. The results suggest that PQ may generate reactive oxygen species, impair the MAPK/p53 signaling pathway, activate angiogenesis and depress apoptosis in the lungs.

Alteration in endometrial proteins during early- and mid-secretory phases of the cycle in women with unexplained infertility

BACKGROUND

Compromised receptivity of the endometrium is a major cause of unexplained infertility, implantation failure and subclinical pregnancy loss. In order to investigate the changes in endometrial protein profile as a cause of unexplained infertility, the current study was undertaken to analyze the differentially expressed proteins of endometrium from early-secretory (LH+2) to mid-secretory phase (LH+7), in women with unexplained infertility.

METHODS

2-D gel electrophoresis was performed to analyze the proteomic changes between early- (n = 8) and mid-secretory (n = 8) phase endometrium of women with unexplained infertility. The differentially expressed protein spots were identified by LC-MS analysis and validated by immunoblotting and immuno-histochemical analysis in early- (n = 4) and mid-secretory (n = 4) phase endometrium of infertile women. Validated proteins were also analyzed in early- (n = 4) and mid-secretory (n = 4) phase endometrium of fertile women.

RESULTS

Nine proteins were found to be differentially expressed between early- and mid- secretory phases of endometrium of infertile women. The expression of Ras-related protein Rap-1b, Protein disulfide isomerase A3, Apolipoprotein-A1 (Apo-A1), Cofilin-1 and RAN GTP-binding nuclear protein (Ran) were found to be significantly increased, whereas, Tubulin polymerization promoting protein family member 3, Superoxide dismutase [Cu-Zn], Sorcin, and Proteasome subunit alpha type-5 were significantly decreased in mid- secretory phase endometrium of infertile women as compared to early-secretory phase endometrium of infertile women. Validation of 4 proteins viz. Sorcin, Cofilin-1, Apo-A1 and Ran were performed in separate endometrial biopsy samples from infertile women. The up-regulated expression of Sorcin and down-regulated expression of Cofilin-1 and Apolipoprotein-A1, were observed in mid-secretory phase as compared to early-secretory phase in case of fertile women.

CONCLUSIONS

De-regulation of the expression of Sorcin, Cofilin-1, Apo-A1 and Ran, during early- to mid-secretory phase may have physiological significance and it may be one of the causes for altered differentiation and/or maturation of endometrium, in women with unexplained infertility.

Anatomo-proteomic characterization of human basal ganglia: focus on striatum and globus pallidus

BACKGROUND

The basal ganglia (BG) are a complex network of subcortical nuclei involved in the coordination and integration of the motor activity. Although these independent anatomical structures are functionally related, the proteome present in each isolated nucleus remains largely unexplored. In order to analyse the BG proteome in a large-scale format, we used a multi-dimensional fractionation approach which combines isolation of anatomically-defined nuclei, and protein/peptide chromatographic fractionation strategies coupled to mass spectrometry.

RESULTS

Using this workflow, we have obtained a proteomic expression profile across striatum and globus pallidus structures among which 1681 proteins were located in caudate nucleus (CN), 1329 in putamen, 1419 in medial globus pallidus (GPi), and 1480 in lateral globus pallidus (GPe), establishing a BG reference proteome to a depth of 2979 unique proteins. Protein interactome mapping highlighted significant clustering of common proteins in striatal and pallidal structures, contributing to oxidative phosphorylation, protein degradation and neurotrophin signalling pathways. In silico analyses emphasized specific pathways represented in striatal and pallidal structures highlighting 5-hydroxytryptamine degradation, synaptic vesicle trafficking, and dopamine, metabotropic glutamate and muscarinic acetylcholine receptor pathways. Additional bioinformatic analyses also revealed that: i) nearly 4% of identified proteins have been previously associated to neurodegenerative syndromes, ii) 11% of protein set tends to localize to synaptic terminal, and iii) 20% of identified proteins were also localized in cerebrospinal fluid (CSF).

CONCLUSIONS

Overall, the anatomo-proteomic profiling of BG complements the anatomical atlas of the human brain transcriptome, increasing our knowledge about the molecular basis of the BG and the etiology of the movement disorders.

Minocycline, levodopa and MnTMPyP induced changes in the mitochondrial proteome profile of MPTP and maneb and paraquat mice models of Parkinson's disease

Mitochondrial dysfunction is the foremost perpetrator of the nigrostriatal dopaminergic neurodegeneration leading to Parkinson's disease (PD). However, the roles played by majority of the mitochondrial proteins in PD pathogenesis have not yet been deciphered. The present study investigated the effects of 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine (MPTP) and combined maneb and paraquat on the mitochondrial proteome of the nigrostriatal tissues in the presence or absence of minocycline, levodopa and manganese (III) tetrakis (1-methyl-4-pyridyl) porphyrin (MnTMPyP). The differentially expressed proteins were identified and proteome profiles were correlated with the pathological and biochemical anomalies induced by MPTP and maneb and paraquat. MPTP altered the expression of twelve while combined maneb and paraquat altered the expression of fourteen proteins. Minocycline, levodopa and MnTMPyP, respectively, restored the expression of three, seven and eight proteins in MPTP and seven, eight and eight proteins in maneb- and paraquat-treated groups. Although levodopa and MnTMPyP rescued from MPTP- and maneb- and paraquat-mediated increase in the microglial activation and decrease in manganese-superoxide dismutase expression and complex I activity, dopamine content and number of dopaminergic neurons, minocycline defended mainly against maneb- and paraquat-mediated alterations. The results demonstrate that MPTP and combined maneb and paraquat induce mitochondrial dysfunction and microglial activation and alter the expression of a bunch of mitochondrial proteins leading to the nigrostriatal dopaminergic neurodegeneration and minocycline, levodopa or MnTMPyP variably offset scores of such changes.

Central nervous system damage due to acute paraquat poisoning: a neuroimaging study with 3.0 T MRI

Paraquat (PQ) is an organic heterocyclic herbicide that is widely used throughout the world. Epidemiological and neuropathological studies have shown that chronic exposure to PQ increases the risk of Parkinson's disease. Patients with acute PQ poisoning show damage to the lungs, liver, and kidneys, and some also show symptoms of central nervous system (CNS) toxicity. However, few studies have focused on the acute neurotoxic changes caused by PQ. Dynamic pathological changes in the human brain cannot be explored in animal models. Thus, to elucidate the impact of acute PQ poisoning on the CNS, neuroimaging studies of poisoned victims, and especially survivors, should be performed. This study reports the first application of magnetic resonance imaging (MRI) techniques on patients with acute PQ poisoning, including survivors. We found significant abnormal signals in the brains of two patients during the acute post-poisoning phase. Using susceptibility weighted imaging (SWI), we documented changes in the corrected phase values for the extrapyramidal ganglia of survivors, and these values correlate with excessive iron deposition. Our diffusion tensor imaging (DTI) results were suggestive of microstructural changes in the extrapyramidal ganglia and hippocampus after PQ poisoning. These neuroimaging results provide an indirect demonstration that acute PQ neurotoxicity exerts a sustained effect during the acute and recovery stages of poisoning.

Rodent models and contemporary molecular techniques: notable feats yet incomplete explanations of Parkinson's disease pathogenesis

Rodent models and molecular tools, mainly omics and RNA interference, have been rigorously used to decode the intangible etiology and pathogenesis of Parkinson's disease (PD). Although convention of contemporary molecular techniques and multiple rodent models paved imperative leads in deciphering the role of putative causative factors and sequential events leading to PD, complete and clear-cut mechanisms of pathogenesis are still hard to pin down. The current article reviews the implications and pros and cons of rodent models and molecular tools in understanding the molecular and cellular bases of PD pathogenesis based on the existing literature. Probable rationales for short of comprehensive leads and future possibilities in spite of the extensive applications of molecular tools and rodent models have also been discussed.

Melatonin as a neuroprotective agent in the rodent models of Parkinson's disease: is it all set to irrefutable clinical translation?

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. Although a few reviews published previously have described the multifaceted efficacy of melatonin against MPTP and 6-OHDA rodent models, due to development and validation of the newer models as well as the extensive studies on the usage of melatonin in entrenched PD models, it is worthwhile to bring up to date note on the usage of melatonin as a neuroprotective agent in PD. This article presents an update on the usage and applications of melatonin in PD models along with incongruous observations. The impending implications in the clinics, success, limitations, and future prospective have also been discussed in this article.

Melatonin or silymarin reduces maneb- and paraquat-induced Parkinson's disease phenotype in the mouse

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. Subsets of these animals were also treated with MB (30mg/kg) and PQ (10mg/kg), twice a week, for 9wk, 2hr after silymarin/melatonin treatment. Locomotor activities along with striatal dopamine content, tyrosine hydroxylase (TH) immunoreactivity, number of degenerating neurons, lipid peroxidation and nitrite content were estimated. Additionally, mRNA expression of vesicular monoamine transporter, cytochrome P-450 2E1 (CYP2E1), and glutathione-S-transferase A4-4 (GSTA4-4), catalytic activities of CYP2E1 and GSTA4-4 and protein expressions of unphosphorylated and phosphorylated p53 (p53 and P-p53), Bax and caspase 9 were measured in control and MB- and PQ-treated mice with either silymarin or melatonin treatments. Silymarin/melatonin significantly offset MB- and PQ-mediated reductions in locomotor activities, dopamine content, TH immunoreactivity, VMAT 2 mRNA expression and the expression of p53 protein. Silymarin/melatonin attenuated the increases in lipid peroxidation, number of degenerating neurons, nitrite content, mRNA expressions of cytochrome P-450 2E1 (CYP2E1) and GSTA4-4, catalytic activities of CYP2E1 and GST and P-p53, Bax and caspase 9 protein expressions. The results demonstrate that silymarin and melatonin offer nigrostriatal dopaminergic neuroprotection against MB- and PQ-induced PD by the modulation of oxidative stress and apoptotic machinery.

Identification of kaempferol-regulated proteins in rat calvarial osteoblasts during mineralization by proteomics

Kaempferol, a flavonoid, promotes osteoblast mineralization in vitro and bone formation in vivo; however, its mechanism of action is yet unknown. We adopted proteomic approach to identify the differential effect of kaempferol on rat primary calvarial osteoblasts during mineralization. The primary rat calvarial osteoblasts were treated with kaempferol (5.0 microM) for 9 days under mineralizing condition that resulted in significant increase in alkaline phosphatase activity and mineralization of the cells. Further, 2-D analysis of the kaempferol-treated osteoblast lysates revealed 18 differentially expressed proteins (nine upregulated and nine downregulated) on the basis of >/<2.0-fold as cut-off (p<0.01) that were then identified by MALDI-TOF MS. These included cytoskeletal proteins, intracellular signaling protein, chaperone, extracellular matrix protein, and proteins involved in glycolysis and cell-matrix interactions. Proteomics data were confirmed by Western blotting and quantitative real-time PCR by randomly selecting two upregulated and two downregulated proteins. Western blot analysis confirmed upregulation of HSP-70 and cytokeratin-14 levels, and downregulation of aldose reductase and caldesmon expression. We further demonstrated that kaempferol treatment inhibits aldose reductase activity in osteoblasts indicating an altered cellular metabolism by decelerating polyol pathway that was associated with the kaempferol-induced osteoblast mineralization. In conclusion, this is a first comprehensive study on the differential regulation of proteins by kaempferol in primary osteoblast, which would further help to elucidate the role of the identified proteins in the process of osteoblast mineralization.

Clorgyline-mediated reversal of neurological deficits in a Complexin 2 knockout mouse

Complexin 2 is a protein modulator of neurotransmitter release that is downregulated in humans suffering from depression, animal models of depression and neurological disorders such as Huntington's disease in which depression is a major symptom. Although complexin 2 knockout (Cplx2-/-) mice are overtly normal, they show significant abnormalities in cognitive function and synaptic plasticity. Here we show that Cplx2-/- mice also have disturbances in emotional behaviours that include abnormal social interactions and depressive-like behaviour. Since neurotransmitter deficiencies are thought to underlie depression, we examined neurotransmitter levels in Cplx2-/- mice and found a significant decrease in levels of noradrenaline and the serotonin metabolite 5-hydroxyindoleacetic acid in the hippocampus. Chronic treatment with clorgyline, an irreversible inhibitor of monoamine oxidase A, restored hippocampal noradrenaline to normal levels (from 60 to 97% of vehicle-treated Cplx2+/+ mice, P<0.001), and reversed the behavioural deficits seen in Cplx2-/- mice. For example, clorgyline-treated Cplx2-/- mice spent significantly more time interacting with a novel visitor mouse compared with vehicle-treated Cplx2-/- mice in the social recognition test (34 compared with 13%, P<0.01). We were also able to reverse the selective deficit seen in mossy fibre-long-term potentiation (MF-LTP) in Cplx2-/- mice using the noradrenergic agonist isoprenaline. Pre-treatment with isoprenaline in vitro increased MF-LTP by 125% (P<0.001), thus restoring it to control levels. Our data strongly support the idea that complexin 2 is a key player in normal neurological function, and that downregulation of complexin 2 could lead to changes in neurotransmitter release sufficient to cause significant behavioural abnormalities such as depression.

Involvement of nitric oxide in maneb- and paraquat-induced Parkinson's disease phenotype in mouse: is there any link with lipid peroxidation?

The study aimed to investigate the involvement of nitric oxide (NO) in maneb (MB)- and paraquat (PQ)-induced Parkinson's disease (PD) phenotype in mouse and its subsequent contribution to lipid peroxidation. Animals were treated intraperitoneally with or without MB and PQ, twice a week for 3, 6 and 9 weeks. In some sets of experiments (9 weeks treated groups), the animals were treated intraperitoneally with or without inducible nitric oxide synthase (iNOS) inhibitor-aminoguanidine, tyrosine kinase inhibitor-genistein, nuclear factor-kappa B (NF-kB) inhibitor-pyrrolidine dithiocarbamate (PDTC) or p38 mitogen activated protein kinase (MAPK) inhibitor-SB202190. Nitrite content and lipid peroxidation were measured in all treated groups along with respective controls. RNA was isolated from the striatum of control and treated mice and reverse transcribed into cDNA. RT-PCR was performed to amplify iNOS mRNA and western blot analysis was done to check its protein level. MB- and PQ-treatment induced nitrite content, expressions of iNOS mRNA and protein and lipid peroxidation as compared with respective controls. Aminoguanidine resulted in a significant attenuation of iNOS mRNA expression, nitrite content and lipid peroxidation demonstrating the involvement of nitric oxide in MB- and PQ-induced lipid peroxidation. Genistein, SB202190 and PDTC reduced the expression of iNOS mRNA, nitrite content and lipid peroxidation in MB- and PQ-treated mouse striatum. The results obtained demonstrate that nitric oxide contributes to an increase of MB- and PQ-induced lipid peroxidation in mouse striatum and tyrosine kinase, p38 MAPK and NF-kB regulate iNOS expression.

Environmental toxins and Parkinson's disease: putative roles of impaired electron transport chain and oxidative stress

Despite recent advancements in the biomedical fields, the etiology and pathogenesis of Parkinson's disease (PD) is still poorly understood, though the crucial roles of oxidative stress and impaired mitochondrial respiration have been suggested in the development of PD. The oxidative modification of the proteins of mitochondrial electron transport chain alters their normal function leading to the state of energy crisis in neurons. Exposure of environmental chemicals such as 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine (MPTP) and rotenone in mouse produces the symptoms akin to PD and therefore these neurotoxins are commonly used in experimental studies on PD. Another environmental toxin, paraquat (a commonly used herbicide) has also been implicated with the onset of PD. The neurotoxicity of these chemicals is accompanied by the blockade of electron flow from NADH dehydrogenase to coenzyme Q. The agents with the ability to improve mitochondrial respiration and ATP production have been shown to exert beneficial effects in PD patients as well as in the animal models of PD. This review summarizes the current research implicating the impairment of mitochondrial respiratory chain and the role of environmental toxins in the pathogenesis of PD.

Multifunctional roles of enolase in Alzheimer's disease brain: beyond altered glucose metabolism

Enolase enzymes are abundantly expressed, cytosolic carbon-oxygen lyases known for their role in glucose metabolism. Recently, enolase has been shown to possess a variety of different regulatory functions, beyond glycolysis and gluconeogenesis, associated with hypoxia, ischemia, and Alzheimer's disease (AD). AD is an age-associated neurodegenerative disorder characterized pathologically by elevated oxidative stress and subsequent damage to proteins, lipids, and nucleic acids, appearance of neurofibrillary tangles and senile plaques, and loss of synapse and neuronal cells. It is unclear if development of a hypometabolic environment is a consequence of or contributes to AD pathology, as there is not only a significant decline in brain glucose levels in AD, but also there is an increase in proteomics identified oxidatively modified glycolytic enzymes that are rendered inactive, including enolase. Previously, our laboratory identified alpha-enolase as one the most frequently up-regulated and oxidatively modified proteins in amnestic mild cognitive impairment (MCI), early-onset AD, and AD. However, the glycolytic conversion of 2-phosphoglycerate to phosphoenolpyruvate catalyzed by enolase does not directly produce ATP or NADH; therefore it is surprising that, among all glycolytic enzymes, alpha-enolase was one of only two glycolytic enzymes consistently up-regulated from MCI to AD. These findings suggest enolase is involved with more than glucose metabolism in AD brain, but may possess other functions, normally necessary to preserve brain function. This review examines potential altered function(s) of brain enolase in MCI, early-onset AD, and AD, alterations that may contribute to the biochemical, pathological, clinical characteristics, and progression of this dementing disorder.

Gene expression profiles of mouse striatum in control and maneb + paraquat-induced Parkinson's disease phenotype: validation of differentially expressed energy metabolizing transcripts

The present study was undertaken to investigate the gene expression patterns of the striatum of control and maneb + paraquat-induced Parkinson's disease (PD) phenotype in mouse to identify the differentially expressed transcripts. The animals were treated with and without maneb (30 mg/kg, i.p.) + paraquat (10 mg/kg, i.p.), twice a week, for 3, 6, and 9 weeks. The RNA was isolated from control and treated mouse striatum and reverse transcribed, and equal quantities of labeled cDNA were mixed and hybridized with mouse 15 k arrays. Comparative transcription patterns showed the time of exposure dependent alteration in the expression of several transcripts associated with various pathways. RT-PCR reconfirmed the differential expression of some energy metabolizing transcripts. The study provides maneb + paraquat-induced differential expression of many transcripts using high-density microarray approach. Few transcripts, which were previously not reported to be associated with neuronal degeneration, were also identified. The results obtained thus suggest that maneb + paraquat induce neurotoxicity in the striatum in a time of exposure dependent manner via multiple pathways and defective energy metabolism could play a critical role.