OBJECTIVETo examine the expression of the tau protein and microtubule-associated proteins in the testis interstitium of aged and young rats.

METHODSSprague-Dawley male rats were divided into a young group(6 months, n = 10) and an aged group(28 months, n = 10). The two steps immunohistochemistry method with the antibody against tau protein and MAP alpha was performed on the testis tissues of the rats.

RESULTSThe results showed that the immunoreactive cells of tau protein of the testis interstilial of the aged rats obviously increased(P < 0.001) than those of the young, while the immunoreactive cells of the microtubule-associated proteins decreased(P < 0.01) in the aged.

CONCLUSIONThe changes in the expression of the tau protein and microtubule-associated proteins may be related to the aging process of the testis.

Aging ; metabolism ; Animals ; Immunohistochemistry ; Male ; Microtubule-Associated Proteins ; analysis ; Rats ; Rats, Sprague-Dawley ; Testis ; chemistry ; tau Proteins ; analysis

O-linked N-acetylglucosamine (O-GlcNAc) represents a key regulatory post-translational modification (PTM) that is reversible and often reciprocal with phosphorylation of serine and threonine at the same or nearby residues. Although recent technical advances in O-GlcNAc site-mapping methods combined with mass spectrometry (MS) techniques have facilitated study of the fundamental roles of O-GlcNAcylation in cellular processes, an efficient technique for examining the dynamic, reciprocal relationships between O-GlcNAcylation and phosphorylation is needed to provide greater insights into the regulatory functions of O-GlcNAcylation. Here, we describe a strategy for selectively identifying both O-GlcNAc- and phospho-modified sites. This strategy involves metal affinity separation of O-GlcNAcylated and phosphorylated peptides, beta-elimination of O-GlcNAcyl or phosphoryl functional groups from the separated peptides followed by dithiothreitol (DTT) conjugation (BEMAD), affinity purification of DTT-conjugated peptides using thiol affinity chromatography, and identification of formerly O-GlcNAcylated or phosphorylated peptides by MS. The combined metal affinity separation and BEMAD approach allows selective enrichment of O-GlcNAcylated peptides over phosphorylated counterparts. Using this approach with mouse brain synaptosomes, we identified the serine residue at 605 of the synapsin-1 peptide, 603QASQAGPGPR612, and the serine residue at 692 of the tau peptide, 688SPVVSGDTSPR698, which were found to be potential reciprocal O-GlcNAcylation and phosphorylation sites. These results demonstrate that our strategy enables mapping of the reciprocal site occupancy of O-GlcNAcylation and phosphorylation of proteins, which permits the assessment of cross-talk between these two PTMs and their regulatory roles.
Acetylglucosamine/*metabolism ; Amino Acid Sequence ; Animals ; Brain/*metabolism ; Chromatography, Affinity ; Glycosylation ; Mice ; Molecular Sequence Data ; Peptides/isolation & purification ; Phosphorylation ; Synapsins/chemistry/*metabolism ; Synaptosomes/*metabolism ; Tandem Mass Spectrometry ; tau Proteins/chemistry/*metabolism

Progressive dementia is described as the first and most prominent symptom of Alzheimer's disease (AD), and hyperphosphorylation of microtubule associated Tau protein (MAPT) plays a key role in neurodegeneration and neuronal dysfunction in AD and other neurodegenerative diseases. This paper reviews several protein kinases and phosphatases which can phosphorylate/dephosphorylate Tau protein, and evaluates a therapeutic strategy based on targeted inhibition of Tau kinases and activation of Tau phosphatases.
Alzheimer Disease ; metabolism ; physiopathology ; Glycogen Synthase Kinase 3 ; antagonists & inhibitors ; metabolism ; Humans ; Neurodegenerative Diseases ; metabolism ; physiopathology ; Phosphoric Monoester Hydrolases ; metabolism ; Phosphorylation ; Protein Kinases ; metabolism ; tau Proteins ; chemistry ; metabolism ; physiology

OBJECTIVETo study the effect of Panax notoginseng saponins (PNS) on (synaptophysin, syp) and tau gene expression in the brain tissue in senescence accelerated mouse prone 8 (SAMP 8).

METHODSAMP8 were randomly divided into 4 groups: PNS 23.38, 93.50 mg x kg(-1) group, huperzin A 0.038 6 mg x kg(-1) x d(-1) group and blank control group; the drug groups were treated with the designed drugs respectively per day by intragastric administration for 4 consecutive weeks, and double distilled water was given to blank control group. After treatment, the mRNA content of tau and syp were assayed by reverse transcription (RT) and real-time polymerase chain reaction (real-time PCR).

RESULTCompared with blank control group, the syp mRNA contents were increased in PNS groups (P < 0.05 or P < 0.01), and the tau mRNA content were not significant difference in all groups.

CONCLUSIONThis study suggests that PNS can up-regulate syp gene expression at transcriptional level in the brain of SAMP 8.

Aging ; drug effects ; metabolism ; Animals ; Brain ; drug effects ; metabolism ; Gene Expression ; drug effects ; genetics ; Mice ; Panax notoginseng ; chemistry ; Protein Tyrosine Phosphatase, Non-Receptor Type 11 ; genetics ; metabolism ; Saponins ; pharmacology ; tau Proteins ; genetics ; metabolism

OBJECTIVETo recognize relationship of protein related neurodegeneration abnormal aggregation in the aged brains with their cognitive and motor functions.

METHODSBrain tissues from the consecutive autopsy cases of the aged from January 2005 to December 2006 in PLA General Hospital were carried out for immunohistochemical staining with beta amyloid, tau, α-synuclein and ubiquitin antibodies. The consortium to establish a registry for Alzheimer's disease (CERAD) was used to semi-quantitatively analyze Aβ positive core plaques density and Braak staging for tau positive neurofibrillary tangles (NFTs) and α-synuclein positive Lewy bodies. In addition, Aβ positive cerebral amyloid angiopathy (CAA), neuritic plaques and various ubiquitin positive structures were also observed. The relationship of these protein abnormal depositions in the aged brains with cognitive and motor functions were analyzed.

RESULTSIn brain tissues of 16 consecutive autopsy cases of the aged from 78 to 95 years, there were 13 cases with Aβ positive core plaques, their density was 2 cases with sparse, 2 cases with moderate and 9 cases with frequent, respectively, according to CREAD.Eight cases with Aβ positive CAA were found, including 6 cases of mild CAA and 2 cases of severe CAA. There were 12 cases with tau positive NFTs, including 6 cases with Braak stageI-II, 4 cases with stage III-IV and 2 cases with stage V-VI. There were 5 cases with frequent Aβ core plaques, meanwhile existing numerous tau/ubiquitin positive neuritic plaques and Braak stage IV-VI of tau positive NFTs, all of them presented cognitive dysfunction. Among 4 other cases with frequent Aβ core plaques, only one case coexisted α-synuclein positive Lewy bodies showed moderate cognitive impairment, remaining 3 cases did not present cognitive dysfunction. There were 4 cases with α-synuclein positive Lewy bodies in the brainstem, and all of these cases presented parkinsonian motor dysfunction. 13 cases with ubiquitin positive structures were found.

CONCLUSIONSBeta amyloid protein positive deposit in the aged brain is an important marker of normal brain aging and cognitive impairment; frequent Aβ core plaques in the neocortex plus Braak IV and above tau positive NFTs are closely related to cognitive dysfunction of Alzheimer's disease; α-synuclein positive Lewy bodies in the brainstem is one of the important pathological markers of parkinsonian motor disorders; ubiquitin deposition involves the development of some characteristic structures of several neurodegenerative diseases.

Aged ; Alzheimer Disease ; metabolism ; pathology ; Amyloid beta-Peptides ; analysis ; Autopsy ; Brain ; pathology ; Brain Chemistry ; Cerebral Amyloid Angiopathy ; Humans ; Neurofibrillary Tangles ; chemistry ; pathology ; Plaque, Amyloid ; Ubiquitin ; analysis ; alpha-Synuclein ; analysis ; tau Proteins ; analysis

OBJECTIVE: To investigate the effects of propofol combined with hypoxia on cognitive function of immature rats and the possible role of p38 pathway and tau protein in mediating such effects. METHODS: Ninety 7-day-old (P7) SD rats were randomized for daily intraperitoneal injection of propofol (50 mg/kg) or lipid emulsion (5.0 mL/kg) for 7 consecutive days. After each injection, the rats were placed in a warm box (38 ℃) with an oxygen concentration of 18% (hypoxia), 21% (normal air), or 50% (oxygen) until full recovery of the righting reflex. Another 90 P7 rats were similarly grouped and received intraperitoneal injections of p-p38 blocker (15 mg/kg) 30 min before the same treaments. The phosphorylated tau protein, total tau protein and p-p38 content in the hippocampus were detected using Western blotting. The spatial learning and memory abilities of the rats were evaluated with Morris water maze test. RESULTS: Compared with lipid emulsion, propofol injection resulted in significantly increased levels of p-p38, phosphorylated tau and total tau proteins in rats with subsequent hypoxic or normal air treatment ( < 0.05), but propofol with oxygen and injections of the blocker before propofol did not cause significant changes in the proteins. Without subsequent oxygenation, the rats receiving injections of propofol, with and without prior blocker injection, all showed significantly prolonged latency time and reduced platform-crossing times and third quadrant residence time compared with the corresponding lipid emulsion groups ( < 0.05). With oxygen treatment, the rats in propofoland blocker-treated groups showed no significant difference in the performance in Morris water maze test from the corresponding lipid emulsion group. The results of Morris water maze test differed significantly between blocker-propofol group and propofol groups irrespective of exposures to different oxygen levels ( < 0.05), but not between the lipid emulsion and blocker group pairs with exposures to different oxygen levels. CONCLUSIONS Propofol combined with hypoxia can affect the expression of tau protein through p38 pathway to impair the cognitive function of immature rats, in which oxygen plays a protective role.
Animals ; Cognitive Dysfunction ; etiology ; metabolism ; Hippocampus ; chemistry ; Hypnotics and Sedatives ; pharmacology ; Hypoxia, Brain ; complications ; metabolism ; MAP Kinase Signaling System ; Maze Learning ; drug effects ; physiology ; Memory ; drug effects ; physiology ; Propofol ; pharmacology ; Random Allocation ; Rats ; Rats, Sprague-Dawley ; tau Proteins ; analysis

This study is to explore the effect of ginsenoside Rb1 on the process of beta-amyloid peptide(25-35) (Abeta(25-35)) -induced hyperphosphorylation of tau protein, and on the level of cyclin-dependent kinase 5 activator, p25/p35. Western blotting and/or immunocytochemical staining were used to detect the levels of phosphorylation of tau protein at the sites of Thr205, Ser396, Ser404 in hippocampal neurons, cdk5 and p25/p35. After exposure to Abeta(25-35) (20 micromol x L(-1)) for 12 h, the levels of tau protein phosphorylation at the sites of Thr205, Ser396, Ser404 were enhanced, the level of p25 was increased, but the level of protein cdk5 was not changed markedly. Pretreatment with ginsenoside Rb1 reduced Abeta(25-35) -induced hyperphosphorylation of tau protein and decreased the lever of p25, but had no effect on cdk5. Ginsenoside Rb1 can attenuate Abeta(25-35) -induced hyperphosphorylation of tau protein through CDK5 signal pathway.
Amyloid beta-Peptides ; antagonists & inhibitors ; Animals ; Cyclin-Dependent Kinase 5 ; metabolism ; Fetus ; Ginsenosides ; isolation & purification ; pharmacology ; Hippocampus ; cytology ; Nerve Tissue Proteins ; metabolism ; Neurons ; metabolism ; Panax ; chemistry ; Phosphorylation ; drug effects ; Plants, Medicinal ; chemistry ; Rats ; Rats, Sprague-Dawley ; Signal Transduction ; tau Proteins ; metabolism

To explore the effect of ginsenoside Rb1 on JNK/p38 MAPK in the process of beta-amyloid peptide (25-35) -induced tau protein hyperphosphorylation, Western blotting and immunocytochemical stain were performed to observe the tau protein phosphorylation and the expression of JNK/p38 MAPK. The level of tau protein phosphorylation in the sites of Ser396 , Ser199/202 and Thr205 increased after rat cortical neurons exposed to 20 micromol x L(-1) Abeta25-35, meanwhile the level of JNK/p38 MAPK also increased after Abeta25-35 treatment for 12 h. Pretreatment with several doses of ginsenoside Rbl markedly attenuated tau protein hyperphosphorylation and the expression of JNK/p38 MAPK. Ginsenoside Rbl markedly attenuated tau protein hyperphosphorylation through JNK/p38 MAPK pathway.
Amyloid beta-Peptides ; antagonists & inhibitors ; Animals ; Cells, Cultured ; Cerebral Cortex ; cytology ; metabolism ; Ginsenosides ; isolation & purification ; pharmacology ; JNK Mitogen-Activated Protein Kinases ; metabolism ; Neurons ; metabolism ; Panax ; chemistry ; Peptide Fragments ; antagonists & inhibitors ; Phosphorylation ; Plants, Medicinal ; chemistry ; Rats ; Rats, Sprague-Dawley ; Signal Transduction ; p38 Mitogen-Activated Protein Kinases ; metabolism ; tau Proteins ; metabolism

Glucagon-like peptide-1 (GLP-1) has been endorsed as a promising and attractive agent in the treatment of type 2 diabetes mellitus (T2DM). Both Alzheimer's disease (AD) and T2DM share some common pathophysiologic hallmarks, such as amyloid beta (Abeta), phosphoralation of tau protein, and glycogen synthase kinase-3. GLP-1 possesses neurotropic properties and can reduce amyloid protein levels in the brain. Based on extensive studies during the past decades, the understanding on AD leads us to believe that the primary targets in AD are the Abeta and tau protein. Combine these findings, GLP-1 is probably a promising agent in the therapy of AD. This review was focused on the biochemistry and physiology of GLP-1, communities between T2DM and AD, new progresses of GLP-1 in treating T2MD and improving some pathologic hallmarks of AD.
Alzheimer Disease ; drug therapy ; metabolism ; physiopathology ; Amino Acid Sequence ; Amyloid beta-Peptides ; metabolism ; Animals ; Brain ; drug effects ; metabolism ; physiopathology ; Diabetes Mellitus, Type 2 ; drug therapy ; metabolism ; physiopathology ; Glucagon-Like Peptide 1 ; chemistry ; metabolism ; pharmacology ; Glucose ; metabolism ; Humans ; Molecular Sequence Data ; tau Proteins ; antagonists & inhibitors ; metabolism

AIMTo explore the effect and the possible mechanism of ginsenoside Rb1 on beta-amyloid peptide (beta-AP)(25-35) -induced tau protein hyperphosphorylation in cortical neurons.

METHODSWestern blotting and immunocytochemical staining were used to detect tau phosphorylation level, total tau and glycogen synthase kinase-3beta (GSK-3beta) in cortical neurons.

RESULTSAfter exposure to beta-AP(25-35) (20 micromol x L(-1)) for 12 h, the levels of tau protein phosphorylation in the sites of Ser 396, Ser 199/202, Thr 231 and total tau were raised. Meanwhile, the expression of GSK-3beta also increased. Pretreatment with ginsenoside Rbl or lithium chloride, a specific inhibitor of GSK-3beta, markedly reduced beta-AP(25-35)-induced tau hyperphosphorylation and the expression of GSK-3beta.

CONCLUSIONGinsenoside Rb1 can attenuate beta AP(25-35)-induced tau protein hyperphosphorylation in cortical neurons by inhibiting the expression of GSK-3beta.

Amyloid beta-Peptides ; antagonists & inhibitors ; Animals ; Cerebral Cortex ; cytology ; metabolism ; Female ; Fetus ; Ginsenosides ; isolation & purification ; pharmacology ; Glycogen Synthase Kinase 3 ; metabolism ; Glycogen Synthase Kinase 3 beta ; Neurons ; metabolism ; Panax ; chemistry ; Peptide Fragments ; antagonists & inhibitors ; Phosphorylation ; Plants, Medicinal ; chemistry ; Rats ; Rats, Sprague-Dawley ; tau Proteins ; metabolism