Induced dural lymphangiogenesis facilities soluble amyloid-beta clearance from brain in a transgenic mouse model of Alzheimer's disease.

Impaired amyloid-ß clearance from the brain is a core pathological event in Alzheimer's disease. The therapeutic effect of current pharmacotherapies is unsatisfactory, and some treatments cause severe side effects. The meningeal lymphatic vessels might be a new route for amyloid-ß clearance. This study investigated whether promoting dural lymphangiogenesis facilitated the clearance of amyloid-ß from the brain. First, human lymphatic endothelial cells were treated with 100 ng/mL recombinant human vascular endothelial growth factor-C (rhVEGF-C) protein. Light microscopy verified that rhVEGF-C, a specific ligand for vascular endothelial growth factor receptor-3 (VEGFR-3), significantly promoted tube formation of human lymphatic endothelial cells in vitro. In an in vivo study, 200 µg/mL rhVEGF-C was injected into the cisterna magna of APP/PS1 transgenic mice, once every 2 days, four times in total. Immunofluorescence staining demonstrated high levels of dural lymphangiogenesis in Alzheimer's disease mice. One week after rhVEGF-C administration, enzyme-linked immunosorbent assay results showed that levels of soluble amyloid-ß were decreased in cerebrospinal fluid and brain. The Morris water maze test demonstrated that spatial cognition was restored. These results indicate that the upregulation of dural lymphangiogenesis facilities amyloid-ß clearance from the brain of APP/PS1 mice, suggesting the potential of the VEGF-C/VEGFR-3 signaling pathway as a therapeutic target for Alzheimer's disease.

Immunization with Bacillus Calmette-Guérin (BCG) alleviates neuroinflammation and cognitive deficits in APP/PS1 mice via the recruitment of inflammation-resolving monocytes to the brain.

The immune system plays a crucial role in the progression of Alzheimer's disease (AD). Recently, immune-dependent cascade induced by systemic immune activation has been verified to play a beneficial role in AD mouse models. Here, we tested whether Bacillus Calmette-Guérin (BCG) immunization alters AD pathology and cognitive dysfunction in APP/PS1 AD mouse model, and with 4Aß1-15 vaccination as positive control. It was found that BCG treatment reversed the cognitive decline to the extent observed in 4Aß1-15 group, but did not reduce the ß-amyloid (Aß) burden in the brain. Then, we demonstrated the enhanced recruitment of inflammation-resolving monocytes across the choroid plexus and perivascular spaces to cerebral sites of plaque pathology in APP/PS1 mice immunized with BCG. Furthermore, elevated splenocyte Foxp3+ regulatory T cell levels in the control APP/PS1 mice were down-regulated back to the wild-type (WT) levels by BCG treatment but not 4Aß1-15 vaccination. In addition, BCG treatment induced the production of more circulating interferon (IFN)-γ than the controls and 4Aß1-15 vaccination. Though the similar reductions in brain levels of pro-inflammatory cytokines were observed in the BCG and 4Aß1-15 groups compared to the controls, only BCG had the great effect in upregulating cerebral anti-inflammatory cytokine levels as well as elevating the expression of neurotrophic factors in the brain of APP/PS1 mice. Thus, it is suggested that BCG exerts a beneficial immunomodulatory effect in APP/PS1 mice through mitigation of systemic immune suppression, induction of IFN-γ response and alleviation of the neuroinflammatory response.

Glucocorticoids Prevent Enterovirus 71 Capsid Protein VP1 Induced Calreticulin Surface Exposure by Alleviating Neuronal ER Stress.

Severe hand-foot-and-mouth disease (HFMD) caused by Enterovirus 71 (EV71) always accompanies with inflammation and neuronal damage in the central nervous system (CNS). During neuronal injuries, cell surface-exposed calreticulin (Ecto-CRT) is an important mediator for primary phagocytosis of viable neurons by microglia. Our data confirmed that brainstem neurons underwent neuronophagia by glia in EV71-induced death cases of HFMD. EV71 capsid proteins VP1, VP2, VP3, or VP4 did not induce apoptosis of brainstem neurons. Interestingly, we found VP1-activated endoplasmic reticulum (ER) stress and autophagy could promote Ecto-CRT upregulation, but ER stress or autophagy alone was not sufficient to induce CRT exposure. Furthermore, we demonstrated that VP1-induced autophagy activation was mediated by ER stress. Meaningfully, we found dexamethasone treatment could attenuate Ecto-CRT upregulation by alleviating VP1-induced ER stress. Altogether, these findings identify VP1-promoted Ecto-CRT upregulation as a novel mechanism of EV71-induced neuronal cell damage and highlight the potential of the use of glucocorticoids to treat severe HFMD patients with CNS complications.

Postnatal development of nestin positive neurons in rat basal forebrain: different onset and topography with choline acetyltransferase and parvalbumin expression.

Our previous studies identified a sub-population of cholinergic neurons which express nestin in the rostral part of the basal forebrain (BF) in normal adult rats. In the present study, the postnatal developmental patterns of nestin, choline acetyl transferase (ChAT) and parvalbumin (PV) positive neurons were explored by means of immunohistochemistry combined with immunofluorescence double label methods. Compared with early onset of ChAT expression (from P1) and delayed onset of PV expression (from P16), nestin positive activity was detected in the BF from P9 and co-expressed by parts of the ChAT positive neurons within the same region during the whole postnatal development process. However, ChAT and PV were not coexpressed by the neurons within the medial septum-diagonal band of Broca (MS-DBB) of BF. These results might imply a composite of separate development patterns displayed by different subpopulations of cholinergic neurons (nestin positive cholinergic neurons and nestin negative cholinergic neurons) within this region. Moreover, the topographic distribution of nestin, ChAT and PV positive neurons also showed different characteristics. In summary, our present study revealed a remarkable timing and topographic difference on the postnatal development of the nestin expression within the MS-DBB of BF compared with ChAT and PV expression. It is further suggested that nestin is re-expressed by cholinergic neurons in the BF after differentiation but not persisted from neuronal precursor cells.

[Molecular mechanisms of Arg77Cys missense mutation and Arg174stop nonsense mutation of factor XIII A gene causing severe factor XIII deficiency].

The present study was aimed to investigate the molecular mechanisms responsible for the pathogenesis of severe factor XIII (FXIII) deficiency. Site-directed mutagenesis was conducted to obtain human FXIIIA expression plasmids bearing the mutations. Wild type FXIIIA recombinant plasmid (pcDNA3.1-FXIIIA-wt) and 2 mutant FXIIIA recombinant plasmids (pcDNA3.1/FXIIIA/77mut, pcDNA3.1/FXIIIA/174mut) were transfected into the cultured COS-7 cells using lipofectamine 2000 transfection reagent, respectively. FXIII activities were measured by the Berichrom(®) FXIII chromogenic assay. The expression levels of FXIIIA mRNA were detected by real-time RT-PCR. The recombinant FXIIIA mutants were determined by using Western blot and ELISA. The results showed that the normalized mRNA levels of 2 mutants in transfected COS-7 cells were 0.82 ± 0.21 and 0.76 ± 0.17, respectively. The relative levels of both mRNA transcripts were not significantly decreased as compared with the wild type (1.06 ± 0.51). FXIII activity and FXIIIA antigen levels in concentrated media of cell expressing the wild type protein were (24.0 ± 2.9)% and (13.2 ± 2.3)%, respectively. FXIII activity and FXIIIA antigen levels in cell lysates containing the wild type recombinant protein were (61.6 ± 30.4)% and (32.8 ± 14.5)%, respectively. However, the antigen levels and activity of 2 mutants were severely decreased as compared to the wild type. It is concluded that both mutations severely disturb the normal expression of FXIIIA protein. The reduction of expression levels and decreased activities of the 2 mutants provides a convincible explanation for the deficiency phenotype in the index case.

Superimposing the 27 crystal protein/inhibitor complexes of ß-secretase to calculate the binding affinities by the linear interaction energy method.

BACE-1 is an important target for designing therapeutic agents for the treatment of Alzheimer's disease. An improved linear interaction energy (LIE) model has been developed to calculate the binding free energies of ß-secretase (BACE-1) by superimposing the 27 crystal BACE-1/inhibitor complexes to put a diverse set of 27 co-crystallized ligands into the binding pocket. These co-crystallized conformations of ligands were set as the initial binding conformations for LIE simulation. The effects of two protein conformations (i.e., 1W51 and 1FKN), two sampling methods (i.e., energy minimization and hybrid Monte Carlo [HMC]), and energy terms were studied. Using 1W51 crystal structure and HMC sampling technique, the best binding affinity model for the full set of ligands was found to have a root-mean-square error of 0.996 kcal/mol.

Chemical identification of nestin-immunoreactive neurons in the rat basal forebrain: a re-examination.

This study explores recently identified neurons that express the protein nestin in the medial septum-diagonal band of Broca (MS-DBB) of adult rats and humans. These nestin positive neurons from MS-DBB are known to project to the hippocampus and frontal cortex of the brain. However, their chemical identification has not been fully elucidated. In this study, we further investigated the chemical identity of the nestin-immunoreactive (ir) neurons in rats using double immunofluorescence labeling and single cell reverse transcription polymerase chain reaction (RT-PCR) techniques. The results of double labeling showed that all nestin-ir neurons exhibited choline acetyltransferase (ChAT) immunoreactivity in the MS-DBB of the basal forebrain. Conversely, only about 43% of the ChAT-ir neurons showed nestin immunoreactivity. In addition, a vast majority of the nestin-ir neurons (95%) were nerve growth factor receptor (NGFR) positive. The nestin-ir neurons were highly distributed in the rostral and intermediated regions of the MS-DBB. Single cell RT-PCR results showed that 90% of the nestin mRNA expressed neurons displayed ChAT mRNA expression as well, but neither the mRNA of the proteins glutamic acid decarboxylases 67 (GAD67) nor vesicular glutamate transporters (VGLUTs). These results provide the first evidence that nestin-ir neurons in the basal forebrain are a subpopulation of the classic cholinergic neurons. With high NGFR proteins activated in the nestin-ir neurons, we propose that the presence of nestin in the cholinergic neurons might be related to the survival and plasticity of the cholinergic neurons.

Effects of the aqueous extract of the Chinese medicine Danggui-Shaoyao-San on rat pineal melatonin synthesis.

OBJECTIVES: The purpose of this study is to investigate if the aqueous extract of the Chinese medicine Danggui-Shaoyao-San (DSS) can increase the plasma level of melatonin and enhance the function of the pineal gland of naturally aged rats. METHODS: The rats were treated with DSS at doses of 3ml or same volume of distilled water by oral administration at 11 p.m. for three weeks. The plasma level of melatonin were measured by radioimmunoassay. The function of pineal gland were measured through three parameters: pineal beta adrenergic receptor binding investigated by [3H]DHA binding; pineal expression of NAT mRNA detected by real-time RT-PCR; phosphorylation of CREB (P-CREB) and total level of CREB (T-CREB) measured by western blot analysis. RESULTS: DSS significantly increased melatonin level at night after oral administration for 3 weeks. By measurement of pineal [3H]DHA binding, it was found DSS improved the beta-adrenergic receptors binding in pineals. The stimulatory effect of DSS on the expression of NAT mRNA in the old rat pineal gland has been demonstrated in this study. Western blot analysis showed that DSS significantly increased phosphorylation of CREB. CONCLUSIONS: Our results indicate that a downstream pathway for DSS induction of melatonin synthesis in the rat pineal gland acts via cyclic AMP-dependent cascade and transcription mechanism.

Differences in c-jun and nNOS expression levels in motoneurons following different kinds of axonal injury in adult rats.

In the peripheral nervous system (PNS), root avulsion causes motoneuron degeneration, but the majority of motoneurons can survive axotomy. In order to study the mechanism of motoneuron degeneration, we compared the expression patterns of c-jun and neuronal nitric oxide synthase (nNOS), the well-known molecular players in PNS regeneration and degeneration, among adult rats having undergone axotomy (Ax), avulsion (Av), or pre-axotomy plus secondary avulsion (Ax + Av) of the brachial plexus. Our results showed that the highest and longest-lasting c-jun activation occurred in Ax, which was much stronger than those in Av and Ax + Av. The time course and intensity of c-jun expression in Ax + Av were similar to those in Av except on day 1, while the pre-axotomy condition resulted in a transient up-regulation of c-jun to a level comparable to that in Ax. Axotomy alone did not induce nNOS expression in motoneurons. Pre-axotomy left-shifted the time course of nNOS induction in Ax + Av compared to that in Av. Motoneuron loss was not evident in Ax, while it was 70% in Av and more than 85% in Ax + Av at 8 weeks postinjury. The survival of motoneurons was positively correlated with c-jun induction, but not with nNOS expression in motoneurons. Moreover, c-jun induction was negatively correlated with nNOS induction in injured motoneurons. Our results indicate that functional crosstalk between c-jun and nNOS might play an important role in avulsion-induced motoneuron degeneration, while c-jun might act as a prerequisite survival factor and nNOS might act as a predictor for the onset of motoneuron degeneration.

[Immunologic tolerance of anti-Abeta antibody in the sera of AD patients].

AIM: To characterize anti-amyloid-beta antibodies in the sera of Alzheimer's disease(AD) patients. METHODS: A special tissue amyloid plaque immunoreactivity (TAPIR) examinations of brains of Tg2576 mice was carried out. Abeta(42)-GST fusion protein was detected by Western blot. and then the survival rate of PC12 cells incubated with the sera and Abeta(42) was measured by MTT assay. RESULTS: The sera in AD patients could not recognize the senile plaque in the brains of Tg2576 mice and could not cross-react with Abeta(42)-GST fusion protein. Furthermore, PC12 cells incubated with the sera from AD patients presented the decreased A value compared with the healthy elderly(P<0.01). CONCLUSION: The anti-Abeta antibodies in the sera of AD patients may have immunologic tolerance to amyloid peptide.

[Synthesizing A beta(1-15) multiple antigen peptide vaccine by indirect conjugation and its immunological activity].

AIM: To explore the method of synthesizing the A beta(1-15) multiple antigen peptide (MAP) vaccine and to identify its quality and the immunological activity. METHODS: MAP A beta(1-15) was synthesized by indirect conjugation and analyzed by RP-HPLC,SDA-PAGE and amino acid analysis. Then, C57BL/6 mice were immunized with synthesized MAP A beta(1-15). The specific anti-A beta antibody in the sera of the immunized mice was identified by ELSA. RESULTS: There was a high and wide peak wave in the RP-HPLC chromatogram. The 8 protein bands identified by SDA-PAGE was identical with 1 to 8 branch of MAP A beta(1-15). The amino acid sequence of synthesized MAP A beta(1-15) was almost similar with the standard. High titer of anti A beta antibody was obtained in the C57BL/6 mice immunized with MAP A beta(1-15). CONCLUSION: MAP A beta(1-15) could be synthesized successfully by indirect conjugation and the synthesized MAP A beta(1-15) had satisfactory immune activity. But the purification of the synthesized complex remained to be a problem.

Effect of temperature on the activation of myocardial KATP channel in guinea pig ventricular myocytes: a pilot study by whole cell patch clamp recording.

BACKGROUND: The myocardial ATP sensitive potassium channel (K(ATP) channel) has been known for more than two decades, the properties of this channel have been intensively investigated, especially the myocardial protection effect by opening this channel. Numerous studies, including hypothermic, using K(ATP) agonists to achieve a hyperpolarizing cardioplegic arrest, have shown a better myocardial protection than potassium arrest. However, there is no evidence showing that K(ATP) channel could be opened by its agonists under profound hypothermia. We investigated the effect of temperature on activation of myocardial K(ATP) channel by nicorandil. METHODS: Isolated ventricular myocytes were obtained by collagenase digestion of the hearts of guinea pigs and stored in KB solution at 4 degrees C. With a steady ground current, the myocytes were perfused with 1 mmol/L nicorandil until a steady IK(ATP) occurred. Then the cells were perfused with 1 mmol/L nicorandil plus 1 micromol/L glybenclamide. Currents signals were recorded on whole cells using patch clamp technique at several temperatures. The temperature of the bath solution around myocytes was monitored and was controlled at 4 degrees C, 10 degrees C, 20 degrees C, 25 degrees C and 35 degrees C respectively. About 10 cells were tested at each temperature, the cells were considered useful only when the outward current could be induced by nicorandil and blocked by glybenclamide. All data were analyzed using Graphpad PRISM 3.0 (Graphpad, San Diego, CA, USA). Nonlinear curve fitting was done in Clampfit (Axon) or Sigmaplot (SPSS). RESULTS: At 4 degrees C, 10 degrees C, 20 degrees C, 25 degrees C and 35 degrees C, the time needed to open the myocardial K(ATP) channel was (81.0 +/- 0) minutes, (50.5 +/- 11.7) minutes, (28.8 +/- 2.3) minutes, (9.4 +/- 10.2) minutes and (2.3 +/- 1.0) minutes respectively (P = 0.003). The linear relationship between temperature and time needed to open the channel was y (min) = (4348.790 - 124.277x)/60, where y (min) is time needed to open K(ATP) channel, x is temperature, correlation coefficient r = -0.942 (P = 0.00), regression coefficient b = -124.277 (P = 0.00). The current densities among different temperatures were statistically different (P = 0.022), the current density was greater after the activation of K(ATP) channel at higher temperatures. The lower the temperature, the fewer cells in which K(ATP) channels could be opened. At 4 degrees C, only one cell in which the K(ATP) channel could be opened, took a quite long time (81 minutes) and the I-V curve was quite untypical. CONCLUSIONS: K(ATP) channel activated by nicorandil is temperature dependent and the temperature linearly related to time needed to open K(ATP) channel; the lower the temperature, the longer the time needed to open channel and the smaller the current density. At profound hypothermia, it is difficult to activate K(ATP) channels.

White matter damage of patients with Alzheimer's disease correlated with the decreased cognitive function.

Increasing evidence demonstrates that there is marked damage and dysfunction in the white matter in Alzheimer's disease (AD). The present study investigates the nature of white matter damage of patients with Alzheimer's disease with diffusion tensor magnetic resonance imaging (DTI) and analyses the relationship between the white matter damage and the cognition function. DTI, as well as T1 fluid attenuated inversion recovery (FLAIR) and T2-FLAIR, was performed on probable patients of Alzheimer's disease, and sex and age matched healthy volunteers to measure the fractional anisotropy (FA) and mean diffusivity (MD) in the genu and splenium of the corpus callosum, anterior and posterior limbs of the internal capsule, and the white matter of frontal, temporal, parietal, and occipital lobes. FA was lower in the splenium of corpus callosum, as well as in the white matter of the frontal, temporal, and parietal lobes from patients with Alzheimer's disease than in the corresponding region from healthy controls and was strongly positive correlated with MMSE scores, whereas FA appeared no different in the anterior and posterior limbs of internal capsule, occipital lobes white matter, and the genu of corpus callosum between the patients and healthy controls. MD was significantly higher in the splenium of corpus callosum and parietal lobes white matter from patients than in that those from healthy controls and was strongly negative correlated with MMSE scores, whereas MD in the anterior and posterior limbs of internal capsule, as well as in frontal, temporal, occipital lobes white matter and the genu of corpus callosum, was not different between the patients and healthy controls. The most prominent alteration of FA and MD was in the splenium of corpus callosum. Our results suggested that white matter of patients with Alzheimer's disease was selectively impaired and the extent of damage had a strong correlation with the cognitive function, and that selective impairment reflected the cortico-cortical and cortico-subcortical disconnections in the pathomechanism of Alzheimer's disease. The values of FA and MD in white matter, especially in the splenium of corpus callosum in AD patients, might be a more appropriate surrogate marker for monitoring the disease progression.

Specific humoral immune responses in rhesus monkeys vaccinated with the Alzheimer's disease-associated beta-amyloid 1-15 peptide vaccine.

BACKGROUND: Alzheimer's disease (AD) is a neurodegenerative disorder characterized by overproduction of beta-amyloid (Abeta), with the subsequent pathologic deposition of Abeta which is important for memory and cognition. Recent studies showed murine models of AD and AD patients inoculated with Abeta(1-42) peptide vaccine had a halted or delayed pathological progression of AD. Unfortunately, the clinical phase IIa trial of Abeta(1-42) peptide vaccine (AN1792) was halted prematurely because of episodes of menigoencephalitis in 18 of the vaccinated patients. The vaccination of BALB/c or Tg2576 transgenic mouse with Abeta(1-15) peptide vaccine is safe and the immune effects are satisfactory. This study further characterizes the specific humoral immune responses in adult rhesus monkeys induced by Abeta(1-15) peptide vaccine. METHODS: Five male adult rhesus monkeys were injected intramuscularly with Abeta(1-15) peptide vaccine at baseline and at weeks 2, 6, 10, 14, 18 and 22. The titers and IgG isotypes of the antibody against Abeta(1-42) in serum was measured by Enzyme-linked Immunosorbent Assay (ELISA). The specificity of the antibody against Abeta(1-42) was determined by Western blot. The Abeta plaques in Tg2576 transgenic mouse brain were stained with the antiserum using immunohistochemistry method. RESULTS: At the eighth week after the vaccination, antibody against Abeta(1-42) began to develop significantly in serum. The titers of the antibody increased following vaccine boosted and reached 1:3840 at the twenty-fourth week, then decreased after the termination of inoculation. The IgG1 was accounted for the highest level in the antiserum pool. The antibody against Abeta(1-42) showed high specificity. The Abeta plaques in Tg2576 transgenic mouse brain were labeled with the antiserum. CONCLUSION: Abeta(1-15) vaccine can induce vigorously specific humoral immune responses in adult rhesus monkey.

[Specific humoral immune response in Rhesus monkeys vaccinated immune response with Abeta42 peptide vaccine].

AIM: To observe the humoral immuneresponse in Rhesus monkey induced by Abeta42 peptide vaccination. METHODS: Five male Rhesus monkeys were received intramuscular injection of Abeta42 peptide vaccine at 0, 2nd, 6th, 10th, 14th, 18th, 22th week. The titers and Ig subclasses of the serum anti-Abeta42 antibody were measured by ELISA. The specificity of the anti-Abeta42 antibody was determined by Western blot. The recognition of Abeta plaques in Tg2576-transgenic mouse brain tissue by anti-Abeta42 serum were detected by immunohistochemical staining. RESULTS: At the 8th week after the vaccination, the serum anti-Abeta42 antibody was detected. The titers of the antibody increased with times of booster inoculation and reached 1:4,320 at the 24th week, then decreased. The produced antibodies were mainly IgG1 and IgG2(IgG2/IgG1>1). The anti-Abeta42 antibody had high specificity. The Abeta plaques in Tg2576-transgenic mouse brain tissue were recognized by the antisera. CONCLUSION: Abeta42 peptide vaccine can induce effectively specific humoral immuneresponse in Rhesus monkey.

Survival, regeneration and functional recovery of motoneurons after delayed reimplantation of avulsed spinal root in adult rat.

We have established that extensive reinnervation and functional recovery follow immediate reimplantation of avulsed ventral roots in adult rats. In the present study, we examined the consequences of reimplantation delayed for 2 weeks after avulsion of the C6 spinal root. Twelve and 20 weeks after delayed reimplantation, 57% and 53% of the motoneurons in the injured spinal segment survived. More than 80% of surviving motoneurons regenerated axons into the reimplanted spinal root. Cholinesterase-silver staining revealed axon terminals on endplates in the denervated muscles. The biceps muscles in reimplanted animals had atrophied less than those in animals with avulsion only, as indicated by muscle wet weight and histological appearance. After electrical stimulation of the motor cortex or the C6 spinal root, typical EMG signals were recorded in biceps of reimplanted animals. The latency of the muscle potential at 20 weeks was similar to that of sham-operated controls. Behavioral recovery was demonstrated by a grooming test and ipsilateral forepaw movements were well coordinated in both voluntary and automatic activities. These results demonstrate that ventral root reimplantation can protect severed motoneurons, enable the severed motoneurons to regenerate axons, and enhance the recovery of forelimb function even when it is delayed for 2 weeks after avulsion.

[Fusion expression of human Abeta42 recombinant protein and detection of Abeta antibody].

OBJECTIVE: To clone and express the recombinant amyloid beta-protein (Abeta(42)) antigen and develop a method for detecting Abeta antibody. METHODS: Two partially complementary fragments of Abeta(42) gene were chemically synthesized for constructing the Abeta(42) gene by PCR. The resultant Abeta(42) gene fragment was subcloned into pGEX-2T expression vector for inducing the expression of GST-Abeta(42) fusion protein, which was purified by affinity chromatography. The antigen specificity and reactivity of the purified GST-Abeta(42) fusion protein to Abeta monoclonal antibody were identified with Western blotting. Using either GST-Abeta(42) fusion protein or Abeta(42) peptide as the coating antigen, an indirect enzyme-linked immunosorbent assay (ELISA) was established for detecting Abeta antibodies in the serum of Abeta(42) polypeptide-immunized SD rats. RESULTS: GST-Abeta(42) fusion protein was successfully expressed as an soluble protein, which, after purification, was found to have a relative molecular mass of 31 kD. About 800 mg of GST-Abeta(42) fusion protein were obtained from l L cell culture with a purity over 95%. Western blotting demonstrated specific reaction of this purified GST-Abeta(42) fusion protein with Abeta monoclonal antibody. The sensitivity of the indirect ELISA for detecting Abeta antibody was about 2 ng/ml using GST-Abeta(42) fusion protein as the coating antigen. There was no significant difference in the results of Abeta antibody detection using either GST-Abeta(42) or Abeta(42) as the coating antigen (P>0.05). CONCLUSION: GST-Abeta(42) fusion protein may serve as a substitute for the expensive Abeta(42) peptide for detecting Abeta antibody.

[Antibody production and its neutralization of Abeta42's cytoxicity in BALB/c mice induced by Abeta42 and its subunit vaccines].

AIM: To explore the production of anti-Abeta42 antibody after immunization with Abeta42 and its subunit peptide vaccines. METHODS: Seventy five male BALB/c with the age of 6 weeks were randomly divided into 5 groups, namely, control group, Abeta42 group, Abeta(36-42) group, Abeta(1-15)group and F Abeta(1-15) group. The BALB/c mice were immunized four times with PBS+MF59 adjuvant, Abeta42+MF59, Abeta(36-42)+heptalysine (MAP)+MF59, Abeta(1-15)+MAP+MF59 and Abeta(1-15)+MAP+Freud's adjuvant, respectively. The titers of specific antibodies in sera and supernatants of brain tissue homogenates from the immunized mice in every group were detected by indirect ELISA. After Abeta42, Abeta(36-42), Abeta(1-15) and F Abeta(1-15) were co-cultured together with cultured PC12 cells for 7 days, the cytotoxicity of the 3 antigen peptides to PC12 cells were determined by MTT colorimetry. In addition, after immune sera from each group were added to culture medium containing 20 mg/L Abeta42 and co-cultured with PC12 cells for 7 days, the survival rate of PC12 cells were examined by MTT assay. RESULTS: The production of anti-Abeta42 antibodies was detected in sera of each experimental group after the second time immunization, and the titer of antibody rose with the increase of immunizing times. In addition, the anti-Abeta42 antibody with low titer was also detected in supernatants of brain tissue homogenates. The Abeta42 could reduce the survival rate of PC12 cells, whereas Abeta(36-42) and Abeta(1-15) had no obvious effect on survival rate of PC12 cells. After immune sera from 4 experimental groups and Abeta42 were co-cultured with PC12 cells, their survival rate was found improved. CONCLUSION: Combination of Abeta42 and its subunit (Abeta(36-42) and Abeta(1-15)) vaccines with MF59 adjuvant can induce BALB/c mice to produce anti-Abeta42 antibody. The antibody may neutralize the cytotoxicity of Abeta42.

Survival, regeneration and functional recovery of motoneurons in adult rats by reimplantation of ventral root following spinal root avulsion.

We investigated the functional recovery of motoneurons after reimplanting an avulsed ventral root in a rat model of traction injury. The eighth cervical root (C8) was avulsed by controlled traction and immediately reimplanted to the spinal cord. Spinal nerves from neighbouring segments (C5, C6, C7 and T1) were ligated and cut. After 12 or 20 weeks, the survival, regeneration and functional recovery of spinal motoneurons were evaluated by Nissl staining, retrograde labelling of motoneurons, NOS histochemistry, histological examination of muscle and nerve-muscle junction, electromyography and behavioural observation. In the control animals, about 14% or 11% of spinal motoneurons survived 12 or 20 weeks postinjury, respectively. By contrast, in animals with ventral root reimplantation, 62% and 55% of motoneurons survived at 12 or 20 weeks postinjury, respectively. Retrograde labelling and histological examination indicated that about 90% of the surviving motoneurons in the C8 segment regenerated axons into the reimplanted ventral root. Staining the muscles with silver and cholinesterase revealed new motor endplates in the reinnervated muscle. Functionally significant electromyographic responses in flexor digitorum superficialis and flexor carpi radialis were observed in experimental animals; however, the average latency of the motor action potentials was greater than normal control. The grasping test showed functional recovery of finger flexors and median nerve. In conclusion, our results indicate that spinal motoneurons can regenerate axons through reimplanted roots and reinnervate muscles to recover partial function.