Application of Surface-Enhanced Raman Spectroscopy Combined with Immunoassay for the Detection of Adrenoceptor Agonists.

Rapid, sensitive, and accurate detection of adrenoceptor agonists is a significant research topic in the fields of food safety and public health. Immunoassays are among the most widely used methods for detecting adrenoceptor agonists. In recent years, surface-enhanced Raman spectroscopy combined with immunoassay (SERS-IA) has become an effective technique for improving detection sensitivity. This review focuses on the innovation of Raman reporter molecules and substrate materials for the SERS-IA of adrenoceptor agonists. In addition, it also investigates the challenges involved in potentially applying SERS-IA in the detection of adrenoceptor agonists. Overall, this review provides insight into the design and application of SERS-IA for the detection of adrenoceptor agonists, which is critical for animal-derived food safety and public health.

A highly sensitive fluorescence biosensor for aflatoxins B1 detection based on polydiacetylene liposomes combined with exonuclease III-assisted recycling amplification.

A fluorescence biosensor for determination of aflatoxin B1 (AFB1) based on polydiacetylene (PDA) liposomes and exonuclease III (EXO III)-assisted recycling amplification was developed. The AFB1 aptamer partially hybridizes with complementary DNA (cDNA), which is released upon recognition of AFB1 by the aptamer. Subsequently, the cDNA hybridizes with hairpin H to form double-stranded DNA that undergoes digestion by EXO III, resulting in the cyclic release of cDNA and generation of capture DNA for further reaction. The capture DNA then hybridizes with probe modified on PDA liposomes, leading to aggregation of liposomes and subsequent fluorescence production. This strategy exhibited a limit of detection of 0.18 ng/mL within the linear range 1-100 ng/mL with a determination coefficient > 0.99. The recovery ranged from 92.81 to 106.45%, with relative standard deviations (RSD) between 1.73 and 4.26%, for corn, brown rice, peanut butter, and wheat samples. The stability, accuracy, and specificity of the method demonstrated the applicability for real sample analysis.

circRNAs as prognostic markers in pediatric acute myeloid leukemia.

Circular RNAs (circRNAs) arise from precursor mRNA processing through back-splicing and have been increasingly recognized for their functions in various cancers including acute myeloid leukemia (AML). However, the prognostic implications of circRNA in AML remain unclear. We conducted a comprehensive genome-wide analysis of circRNAs using RNA-seq data in pediatric AML. We revealed a group of circRNAs associated with inferior outcomes, exerting effects on cancer-related pathways. Several of these circRNAs were transcribed directly from genes with established functions in AML, such as circRUNX1, circWHSC1, and circFLT3. Further investigations indicated the increased number of circRNAs and linear RNAs splicing were significantly correlated with inferior clinical outcomes, highlighting the pivotal role of splicing dysregulation. Subsequent analysis identified a group of upregulated RNA binding proteins in AMLs associated with high number of circRNAs, with TROVE2 being a prominent candidate, suggesting their involvement in circRNA associated prognosis. Through the integration of drug sensitivity data, we pinpointed 25 drugs that could target high-risk AMLs characterized by aberrant circRNA transcription. These findings underscore prognostic significance of circRNAs in pediatric AML and offer an alternative perspective for treating high-risk cases in this malignancy.

Simultaneous detection of AFB1 and aflD gene by "Y" shaped aptamer fluorescent biosensor based on double quantum dots.

The developed method for simultaneous detection of aflatoxin B1 (AFB1) and aflD genes can effectively monitor from the source and reduce the safety problems and economic losses caused by the production of aflatoxin, which can be of great significance for food safety regulations. In this paper, we constructed a sensitive and convenient fluorescent biosensor to detect AFB1 and aflD genes simultaneously based on fluorescence resonance energy transfer (FRET) between quantum dots (QDs) and a black hole quenching agent. A stable "Y" shaped aptasensor was employed as the detection platform and a double quantum dot labeled DNA fragment was utilized to be the sensing element in this work. When the targets of AFB1 and aflD genes were presented in the solution, the aptamer in the "Y" shaped probe is specifically recognized by the target. At this time, both Si-carbon quantum dots (Si-CDs) and CdTe QDs are far away from the BHQ1 and BHQ3 to recover the fluorescence. The linear range of the prepared fluorescence simultaneous detection method was as wide as 0.5-500 ng·mL-1 with detection lines of 0.64 ng·mL-1 for AFB1 and 0.5-500 nM with detection lines of 0.75 nM for aflD genes (3σ/k). This fabricated fluorescent biosensor was further validated in real rice flour and corn flour samples, which also achieved good results. The recoveries were calculated by comparing the known and found amounts of AFB1 which ranged from 88.4 to approximately 115.32% in the rice flour samples and 90.7 ~ 102.58% in the corn flour samples. The recoveries of aflD genes ranged from 84.32 to approximately 109.3% in the rice flour samples and 89.48 ~ 100.99% in the corn flour samples. Therefore, the proposed biosensor can significantly improve food safety and quality control through a simple, fast, and sensitive agricultural product monitoring and detection system.

High-Energy, Whole-Body Proton Irradiation Differentially Alters Long-Term Brain Pathology and Behavior Dependent on Sex and Alzheimer's Disease Mutations.

Whole-body exposure to high-energy particle radiation remains an unmitigated hazard to human health in space. Ongoing experiments at the NASA Space Radiation Laboratory and elsewhere repeatedly show persistent changes in brain function long after exposure to simulations of this unique radiation environment, although, as is also the case with proton radiotherapy sequelae, how this occurs and especially how it interacts with common comorbidities is not well-understood. Here, we report modest differential changes in behavior and brain pathology between male and female Alzheimer's-like and wildtype littermate mice 7-8 months after exposure to 0, 0.5, or 2 Gy of 1 GeV proton radiation. The mice were examined with a battery of behavior tests and assayed for amyloid beta pathology, synaptic markers, microbleeds, microglial reactivity, and plasma cytokines. In general, the Alzheimer's model mice were more prone than their wildtype littermates to radiation-induced behavior changes, and hippocampal staining for amyloid beta pathology and microglial activation in these mice revealed a dose-dependent reduction in males but not in females. In summary, radiation-induced, long-term changes in behavior and pathology, although modest, appear specific to both sex and the underlying disease state.

Long-Term Sex- and Genotype-Specific Effects of 56Fe Irradiation on Wild-Type and APPswe/PS1dE9 Transgenic Mice.

Space radiation presents a substantial threat to travel beyond Earth. Relatively low doses of high-energy particle radiation cause physiological and behavioral impairments in rodents and may pose risks to human spaceflight. There is evidence that 56Fe irradiation, a significant component of space radiation, may be more harmful to males than to females and worsen Alzheimer's disease pathology in genetically vulnerable models. Yet, research on the long-term, sex- and genotype-specific effects of 56Fe irradiation is lacking. Here, we irradiated 4-month-old male and female, wild-type and Alzheimer's-like APP/PS1 mice with 0, 0.10, or 0.50 Gy of 56Fe ions (1GeV/u). Mice underwent microPET scans before and 7.5 months after irradiation, a battery of behavioral tests at 11 months of age and were sacrificed for pathological and biochemical analyses at 12 months of age. 56Fe irradiation worsened amyloid-beta (Aß) pathology, gliosis, neuroinflammation and spatial memory, but improved motor coordination, in male transgenic mice and worsened fear memory in wild-type males. Although sham-irradiated female APP/PS1 mice had more cerebral Aß and gliosis than sham-irradiated male transgenics, female mice of both genotypes were relatively spared from radiation effects 8 months later. These results provide evidence for sex-specific, long-term CNS effects of space radiation.

Focused ultrasound with anti-pGlu3 Aß enhances efficacy in Alzheimer's disease-like mice via recruitment of peripheral immune cells.

Pyroglutamate-3 amyloid-ß (pGlu3 Aß) is an N-terminally modified, pathogenic form of amyloid-ß that is present in cerebral amyloid plaques and vascular deposits. Here, we used focused ultrasound (FUS) with microbubbles to enhance the intravenous delivery of an Fc-competent anti-pGlu3 Aß monoclonal antibody, 07/2a mAb, across the blood brain barrier (BBB) in an attempt to improve Aß removal and memory in aged APP/PS1dE9 mice, an Alzheimer's disease (AD)-like model of amyloidogenesis. First, we demonstrated that bilateral hippocampal FUS-BBB disruption (FUS-BBBD) led to a 5.5-fold increase of 07/2a mAb delivery to the brains compared to non-sonicated mice 72 h following a single treatment. Then, we determined that three weekly treatments with 07/2a mAb alone improved spatial learning and memory in aged, plaque-rich APP/PS1dE9 mice, and that this improvement occurred faster and in a higher percentage of animals when combined with FUS-BBBD. Mice given the combination treatment had reduced hippocampal plaque burden compared to PBS-treated controls. Furthermore, synaptic protein levels were higher in hippocampal synaptosomes from mice given the combination treatment compared to sham controls, and there were more CA3 synaptic puncta labeled in the APP/PS1dE9 mice given the combination treatment compared to those given mAb alone. Plaque-associated microglia were present in the hippocampi of APP/PS1dE9 mice treated with 07/2a mAb with and without FUS-BBBD. However, we discovered that plaque-associated Ly6G+ monocytes were only present in the hippocampi of APP/PS1dE9 mice that were given FUS-BBBD alone or even more so, the combination treatment. Lastly, FUS-BBBD did not increase the incidence of microhemorrhage in mice with or without 07/2a mAb treatment. Our findings suggest that FUS is a useful tool to enhance delivery and efficacy of an anti-pGlu3 Aß mAb for immunotherapy either via an additive effect or an independent mechanism. We revealed a potential novel mechanism wherein the combination of 07/2a mAb with FUS-BBBD led to greater monocyte infiltration and recruitment to plaques in this AD-like model. Overall, these effects resulted in greater plaque removal, sparing of synapses and improved cognitive function without causing overt damage, suggesting the possibility of FUS-BBBD as a noninvasive method to increase the therapeutic efficacy of drugs or biologics in AD patients.

MXene (Ti3C2) Based Pesticide Delivery System for Sustained Release and Enhanced Pest Control.

A multifunctional nanomaterials based pesticide delivery system provides a powerful strategy for the efficient utilization of pesticides. We present here the application of a 2D MXene (Ti3C2) nanomaterial for pesticide delivery and plant protection. Avermectin (AV), a hydrophobic and unstable insecticide, was chosen as the model pesticide. In our study, AV@Ti3C2 was formed by fast adsorption of AV on Ti3C2, with a maximum loading capacity of 81.44%. Compared with hydrophobic AV, AV@Ti3C2 exhibited significantly improved water solubility, which is beneficial for ensuring the bioactivity of pesticide. The AV@Ti3C2 nanoformulation showed pH responsive slow-release behavior, overcoming the burst-release of conventional AV formulations. Besides, AV@Ti3C2 possessed excellent photostability under UV irradiation, which prolonged the persistent period of AV. Therefore, AV@Ti3C2 performed sustaining and enhanced antipest activity, according to the bioactivity assay. Furthermore, AV@Ti3C2 showed satisfactory biosafety, with no negative effect to the germination and growth of maize. Our current research provides a potential candidate, AV@Ti3C2, for pest control, and also broadens the application of 2D MXene materials in plant protection and sustainable agriculture.

Space-like 56Fe irradiation manifests mild, early sex-specific behavioral and neuropathological changes in wildtype and Alzheimer's-like transgenic mice.

Space travel will expose people to high-energy, heavy particle radiation, and the cognitive deficits induced by this exposure are not well understood. To investigate the short-term effects of space radiation, we irradiated 4-month-old Alzheimer's disease (AD)-like transgenic (Tg) mice and wildtype (WT) littermates with a single, whole-body dose of 10 or 50 cGy 56Fe ions (1 GeV/u) at Brookhaven National Laboratory. At ~1.5 months post irradiation, behavioural testing showed sex-, genotype-, and dose-dependent changes in locomotor activity, contextual fear conditioning, grip strength, and motor learning, mainly in Tg but not WT mice. There was little change in general health, depression, or anxiety. Two months post irradiation, microPET imaging of the stable binding of a translocator protein ligand suggested no radiation-specific change in neuroinflammation, although initial uptake was reduced in female mice independently of cerebral blood flow. Biochemical and immunohistochemical analyses revealed that radiation reduced cerebral amyloid-ß levels and microglia activation in female Tg mice, modestly increased microhemorrhages in 50 cGy irradiated male WT mice, and did not affect synaptic marker levels compared to sham controls. Taken together, we show specific short-term changes in neuropathology and behaviour induced by 56Fe irradiation, possibly having implications for long-term space travel.

A SERS-based multiple immuno-nanoprobe for ultrasensitive detection of neomycin and quinolone antibiotics via a lateral flow assay.

The authors describe an ultrasensitive method for simultaneous detection of neomycin (NEO) and quinolones antibiotics (QNS). It is based on the use of (a) two immuno-nanoprobes (a probe for NEO and a probe for QNS), (b) surface-enhanced Raman scattering (SERS) detection, and (c), a portable lateral flow assay (LFA). The two probes consist of gold nanoparticles (AuNPs) conjugated to the Raman active molecule 4-aminothiophenol (PATP), and to monoclonal antibody against NEO (NEO mAb) or against NOR (NOR mAb). Quantitative detection of NEO and QNS was realized via SERS of the PATP-coated AuNPs captured in the test line of a LFA. Under optimized condition, the visual limits of LFA are 10 ng·mL-1 for NEO and 200 ng·mL-1 for NOR, and with LODs down to 0.37 pg·mL-1 and 0.55 pg·mL-1 by using SERS. The NEO test line is not interfered by the NEO analogues gentamycin, streptomycin and tobramycin, but the NOR test line suffers from different degrees of cross-reactivity (CR) to 12 common other QNS, the CRs ranging from 1.5% to 136%. The recoveries of NEO and NOR from spiked milk samples ranged between 86% and 121%, with relative standard deviations (RSD) from 3% to 6%. The method is highly sensitive, accurate and effective. It may be applied to simultaneous detection of NEO and 8 QNS, including NOR, enoxacin, ciprofloxacin, ofloxacin, fleroxacin, marbofloxacin, enrofloxacin, and pefloxacin. Graphical abstract Schematic of a lateral flow assay (LFA) based on an indirect competitive model. By using two test lines, the LFA can detect the neomycin and quinolones antibiotics simultaneously. Based on the surface-enhanced Raman scattering (SERS), the LFA shows high sensitivity to antibiotics with low limit of detection.

Eu3+ -labeled IgG-based time-resolved fluoroimmunoassay for highly sensitive detection of aflatoxin B1 in feed.

BACKGROUND: Aflatoxin B1 (AFB1 ) is a kind of toxic and carcinogenic mycotoxin. A time-resolved fluoroimmunoassay (TRFIA) was established for quantitative detection of AFB1 in feed using Eu3+ -labeled IgG as tracer. RESULTS: Monoclonal antibody (McAb) against AFB1 (9B11-D7) was prepared through immunization and cell fusion and was identified as high affinity, specificity and sensibility by enzyme-linked immunosorbent assay (ELISA). The 50% inhibition value (IC50 ) was 0.81 ng mL-1 , the limit of detection (LOD) was 0.10 ng mL-1 and detection range was 0.10-3.94 ng mL-1 . Goat anti-mouse immunoglobulin G (IgG) was modified by Eu3+ -DATT, generating Eu3+ -labeled IgG. Under optimal assay conditions, TRFIA was shown to be highly sensitive and specific in detection of AFB1 . The IC50 and LOD were 94.73 pg mL-1 and 3.55 pg mL-1 , respectively, and detection range was 3.55-1.11 × 103 pg mL-1 . Cross-reactivity with AFM1 , AFB2 , AFG1 and AFG2 was 31.26%, 37.6%, 127.46% and 35.74%, respectively, but zero with other analogues. In determination of AFB1 spiked in feed sample, TRFIA showed high accuracy and precision. The average recoveries ranged from 93.71% to 97.80%, and coefficient of variation was 1.25-3.73%. Good correlation between TRFIA and HPLC was demonstrated for determination of AFB1 in feeds, confirming the reliability of the developed method. CONCLUSION: The developed TRFIA exhibited good potential for employment in the ultrasensitive detection of AFB1 in feed and could be used to determine total aflatoxins. © 2017 Society of Chemical Industry.

Utilization of a lateral flow colloidal gold immunoassay strip based on surface-enhanced Raman spectroscopy for ultrasensitive detection of antibiotics in milk.

An ultrasensitive method for the detection of antibiotics in milk is developed based on inexpensive, simple, rapid and portable lateral flow immunoassay (LFI) strip, in combination with high sensitivity surface-enhanced Raman spectroscopy (SERS). In our strategy, an immunoprobe was prepared from colloidal gold (AuNPs) conjugated with both a monoclonal antibody against neomycin (NEO-mAb) and a Raman probe molecule 4-aminothiophenol (PATP). The competitive interaction with immunoprobe between free NEO and the coated antigen (NEO-OVA) resulted in the change of the amount of the immobilized immunoprobe on the paper substrate. The LFI procedure was completed within 15min. The Raman intensity of PATP on the test line of the LFI strip was measured for the quantitative determination of NEO. The IC50 and the limit of detection (LOD) of this assay are 0.04ng/mL and 0.216pg/mL of NEO, respectively. There is no cross-reactivity (CR) of the assay with other compounds, showing high specificity of the assay. The recoveries for milk samples with added NEO are in the range of 89.7%-105.6% with the relative standard deviations (RSD) of 2.4%-5.3% (n=3). The result reveals that this method possesses high specificity, sensitivity, reproducibility and stability, and can be used to detect a variety of antibiotic residues in milk samples.

Complement C3 deficiency protects against neurodegeneration in aged plaque-rich APP/PS1 mice.

The complement cascade not only is an innate immune response that enables removal of pathogens but also plays an important role in microglia-mediated synaptic refinement during brain development. Complement C3 is elevated in Alzheimer's disease (AD), colocalizing with neuritic plaques, and appears to contribute to clearance of Aß by microglia in the brain. Previously, we reported that C3-deficient C57BL/6 mice were protected against age-related and region-specific loss of hippocampal synapses and cognitive decline during normal aging. Furthermore, blocking complement and downstream iC3b/CR3 signaling rescued synapses from Aß-induced loss in young AD mice before amyloid plaques had accumulated. We assessed the effects of C3 deficiency in aged, plaque-rich APPswe/PS1dE9 transgenic mice (APP/PS1;C3 KO). We examined the effects of C3 deficiency on cognition, Aß plaque deposition, and plaque-related neuropathology at later AD stages in these mice. We found that 16-month-old APP/PS1;C3 KO mice performed better on a learning and memory task than did APP/PS1 mice, despite having more cerebral Aß plaques. Aged APP/PS1;C3 KO mice also had fewer microglia and astrocytes localized within the center of hippocampal Aß plaques compared to APP/PS1 mice. Several proinflammatory cytokines in the brain were reduced in APP/PS1;C3 KO mice, consistent with an altered microglial phenotype. C3 deficiency also protected APP/PS1 mice against age-dependent loss of synapses and neurons. Our study suggests that complement C3 or downstream complement activation fragments may play an important role in Aß plaque pathology, glial responses to plaques, and neuronal dysfunction in the brains of APP/PS1 mice.

Complement and microglia mediate early synapse loss in Alzheimer mouse models.

Synapse loss in Alzheimer's disease (AD) correlates with cognitive decline. Involvement of microglia and complement in AD has been attributed to neuroinflammation, prominent late in disease. Here we show in mouse models that complement and microglia mediate synaptic loss early in AD. C1q, the initiating protein of the classical complement cascade, is increased and associated with synapses before overt plaque deposition. Inhibition of C1q, C3, or the microglial complement receptor CR3 reduces the number of phagocytic microglia, as well as the extent of early synapse loss. C1q is necessary for the toxic effects of soluble ß-amyloid (Aß) oligomers on synapses and hippocampal long-term potentiation. Finally, microglia in adult brains engulf synaptic material in a CR3-dependent process when exposed to soluble Aß oligomers. Together, these findings suggest that the complement-dependent pathway and microglia that prune excess synapses in development are inappropriately activated and mediate synapse loss in AD.

Complement C3-Deficient Mice Fail to Display Age-Related Hippocampal Decline.

The complement system is part of the innate immune response responsible for removing pathogens and cellular debris, in addition to helping to refine CNS neuronal connections via microglia-mediated pruning of inappropriate synapses during brain development. However, less is known about the role of complement during normal aging. Here, we studied the role of the central complement component, C3, in synaptic health and aging. We examined behavior as well as electrophysiological, synaptic, and neuronal changes in the brains of C3-deficient male mice (C3 KO) compared with age-, strain-, and gender-matched C57BL/6J (wild-type, WT) control mice at postnatal day 30, 4 months, and 16 months of age. We found the following: (1) region-specific and age-dependent synapse loss in aged WT mice that was not observed in C3 KO mice; (2) age-dependent neuron loss in hippocampal CA3 (but not in CA1) that followed synapse loss in aged WT mice, neither of which were observed in aged C3 KO mice; and (3) significantly enhanced LTP and cognition and less anxiety in aged C3 KO mice compared with aged WT mice. Importantly, CA3 synaptic puncta were similar between WT and C3 KO mice at P30. Together, our results suggest a novel and prominent role for complement protein C3 in mediating aged-related and region-specific changes in synaptic function and plasticity in the aging brain. Significance statement: The complement cascade, part of the innate immune response to remove pathogens, also plays a role in synaptic refinement during brain development by the removal of weak synapses. We investigated whether complement C3, a central component, affects synapse loss during aging. Wild-type (WT) and C3 knock-out (C3 KO) mice were examined at different ages. The mice were similar at 1 month of age. However, with aging, WT mice lost synapses in specific brain regions, especially in hippocampus, an area important for memory, whereas C3 KO mice were protected. Aged C3 KO mice also performed better on learning and memory tests than aged WT mice. Our results suggest that complement C3, or its downstream signaling, is detrimental to synapses during aging.

Potassium 2-(1-hydroxypentyl)-benzoate improves learning and memory deficits in chronic cerebral hypoperfused rats.

Potassium 2-(1-hydroxypentyl)-benzoate (dl-PHPB), the pre-drug of 3-n-butylphthalide (dl-NBP), had the significantly therapeutic effect on the acute cerebral ischemia. The present study was to investigate the effect of dl-PHPB on the cognitive deficits induced by chronic cerebral hypoperfusion. Rats were orally administered three doses of dl-PHPB (13, 39 and 129mg/kg), dl-NBP 100mg/kg, and piracetam 600mg/kg daily for 21 days after the bilateral permanent occlusion of the common carotid arteries. The results showed that dl-PHPB, dl-NBP and piracetam significantly improved the spatial learning and memory deficits, and the effectiveness of dl-PHPB at dose of 39mg/kg was strongest. Meanwhile, the drugs decreased superoxide dismutase activity, reduced lipid peroxide and astrocyte activation in the cortex of the hypoperfused rats. Furthermore, dl-PHPB markedly reduced white matter rarefaction. The results indicated that preventing neuropathological alterations, inhibiting oxidative damage and inflammatory reaction might contribute to the improvement of dl-PHPB on hypoperfusion-induced cognitive deficits. Therefore, dl-PHPB has therapeutic potential for the treatment of dementia caused by decrease of cerebral blood flow.

Novel neuroprotectant chiral 3-n-butylphthalide inhibits tandem-pore-domain potassium channel TREK-1.

AIM: To study the effects of 3-n-butylphthalide (NBP) on the TREK-1 channel expressed in Chinese hamster ovary (CHO) cells. METHODS: Whole-cell patch-clamp recording was used to record TREK-1 channel currents. The effects of varying doses of l-NBP on TREK-1 currents were also observed. Current-clamp recordings were performed to measure the resting membrane potential in TREK-1-transfected CHO (TREK-1/CHO) and wild-type CHO (Wt/CHO) cells. RESULTS: l-NBP (0.01-10 µmol/L) showed concentration-dependent inhibition on TREK-1 currents (IC(50)=0.06±0.03 µmol/L), with a maximum current reduction of 70% at a concentration of 10 µmol/L. l-NBP showed a more potent inhibition on TREK-1 current than d-NBP or dl-NBP. This effect was partially reversed upon washout and was not voltage-dependent. l-NBP 10 µmol/L elevated the membrane potential in TREK-1/CHO cells from -55.3 mV to -42.9 mV. However, it had no effect on the membrane potential of Wt/CHO cells. CONCLUSION: 1-NBP potently inhibited TREK-1 current and elevated the membrane potential, which may contribute to its neuroprotective activity.

Strain- and age-related alteration of proteins in the brain of SAMP8 and SAMR1 mice.

In order to discover and identify the key protein biomarkers in the aging process, we performed a differential proteomic analysis of hippocampus and cortex in 5- and 15-month old senescence-accelerated mouse prone 8 (SAMP8) as well as in control strain SAM/resistant 1 (SAMR1). Using 2-DE combined with MALDI TOF/TOF mass spectrometry, about 1700 protein spots were isolated, and three groups of differentially expressed proteins were identified. The first group contained the strain-specific and non-age-related differential proteins that were differentially expressed in SAMP8 compared with SAMR1 mice. The changes might be implicated in the genetic difference between SAMP8 and SAMR1 mice; specifically, the proteins ubiquitin carboxyl-terminal esterase L3, mitofilin, adenylate kinase 4, and an unnamed protein product (gi|12847201). The proteins in the second group were age-specific, which were differentially expressed between 5- and 15-month old SAM mice. Those proteins are particularly interesting since the changes were aging-related and some of them were previously reported to be expressed in Alzheimer's disease patients. These proteins included N-myc downstream regulated gene 2, enolase 2, Cu/Zn superoxide dismutase, myosin, and two unnamed protein products (gi|74214304 and gi|74178239). The protein in the third group was SAMP8 specific-age-related protein, which was identified as heme binding protein 1. The present study provides new information about SAMP8 specific and aging-related protein changes in brain. Further investigations will be performed to reveal the significance of these proteins in brain aging process and the potential roles as biomarkers for effective diagnosis and therapy.

Striatal 19S Rpt6 deficit is related to alpha-synuclein accumulation in MPTP-treated mice.

Striatal mitochondrial proteins were investigated using proteomics in the 1-methyl 4-phenyl-1,2,3,6-tetrahydropyridine (MPTP) mouse model of Parkinson's disease. Four proteins, 19S proteasome ATPase Rpt6 (19S Rpt6), Lectin-related nature killer cell receptor LY 49S, Zinc finger A20 domain containing 1, and the sodium channel-associated protein 1 isoform 2, were significantly decreased while alpha-synuclein was increased in MPTP-treated mice. The altered levels of 19S Rpt6 and alpha-synuclein were further verified by Western blot. Experiments using small interfering RNA (siRNA) showed that alpha-synuclein was increased by 50% in cultured striatal neurons when 19S Rpt6 was knocked down. Taken together, our results imply that a deficiency in 19S Rpt6 may be partially related to the MPTP-induced increase in alpha-synuclein in the striatum.