Alzheimer Disease ; genetics ; metabolism ; therapy ; Humans ; tau Proteins ; genetics ; metabolism

Extracellular deposition of β-amyloid (Aβ) and intracellular hyperphosphorylated tau are the predominant pathological changes in Alzheimer's disease (AD). Increasing evidence demonstrates a critical role of a variety of small GTPases, namely Ras-related proteins (Rabs), in the pathogenesis of AD. As crucial regulators of intracellular membrane trafficking, alteration in Rab protein expression and function represents one of the primary factors contributing to the abnormal membrane trafficking in AD. Additionally, the Rab GTPases are also involved in the development of Aβ, tau and other pathological changes associated with AD. In this article, we conduct a comprehensive review on the primary functions of multiple Rab proteins and their involvement in the pathogenesis of AD.
Humans ; Alzheimer Disease ; rab GTP-Binding Proteins/metabolism* ; Amyloid beta-Peptides/metabolism* ; tau Proteins/metabolism*

Rats ; Animals ; Okadaic Acid/toxicity* ; PC12 Cells ; Triterpenes ; tau Proteins/metabolism* ; Phosphorylation

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

OBJECTIVETo investigate the effect of acteoside on SK-N-SH nerve cell injury induced by okadaic acid (OA).

METHODSK-N-SH nerve cells were processed with 20 nmol * L OA to establish the Alzheimer's disease (AD) cellular model, and 5, 10, 20 mg . L-1 acteoside was used to antagonize against its effect. Cell morphology was observed under inverted microscope. The cell survival rate was detected with MTT, and the LDH release rate was measured by enzyme label kit. Western blot was applied to determine the expression of phosphorylation tau proteins in nerve cells.

RESULTThe acteoside could significantly improve SK-N-SH cell morphology, enhance the cell survival rate, decrease the cell LDH release rate and the expression of phosphorylated tau proteins at p-Ser 199/202 and p-Ser 404 sites, up-regulated the expression of at non-phosphorylated tau proteins at Ser 202 site and Ser 404 sites.

CONCLUSIONActeoside has significant protective effect on nerve cell injury induced by OA.

Alzheimer Disease ; metabolism ; Cell Line ; Cell Survival ; drug effects ; Glucosides ; pharmacology ; Humans ; Okadaic Acid ; Phenols ; pharmacology ; tau Proteins ; metabolism

Alzheimer Disease ; complications ; pathology ; therapy ; Amyloid beta-Peptides ; metabolism ; Humans ; Mitochondria ; physiology ; Mitochondrial Diseases ; etiology ; tau Proteins ; metabolism

AIMTo observe expressions and changes of Tau protein, pSer202 and Tau protein's contents during the differentiation process of bone-marrow mesenchymal stem cells (MSCs) into neural cells, and discuss Tau's effects on it.

METHODSEGF and bFGF were combined for the induction of 4th, 8th, and 12th-MSCs into neural cells. Expressions of Tau protein and pSer202 were tested by immunocytochemistry. ELISA assay was applied for testing Tau protein's contents during differentiation process.

RESULTSPositive rates of Tau protein in uninduced MSCs of 4th, 8th, and 12th-MSCs were under < 6%; After 14-day induction, the cellular morphologic characteristics in different passages were very similar to neurons, positive rates of Tau protein had no significant differences between passages (P > 0.05), but had differences with their uninduced groups (P < 0.05). There hadn't had expression of pSer202 in uninduced and induced groups of passages. ELISA assay indicated that there was an upward tendency in Tau protein's contents during the 14-day induction process, those in the 14th day had no significant differences between passages too (P > 0.05).

CONCLUSIONThe increase in Tau protein's expressions and its non-phosphorylated state may make for MSCs differentiating into normal neural cells and formation of neuronal processes.

Animals ; Bone Marrow Cells ; cytology ; Cell Differentiation ; Cells, Cultured ; Guinea Pigs ; Mesenchymal Stromal Cells ; cytology ; Neurons ; cytology ; tau Proteins ; metabolism

OBJECTIVETo investigate the effect of aluminum trichloride on the abnormal phosphorylation of tau protein in SH-SY5Y cells.

METHODSSH-SY5Y cells were assigned to control group and aluminum trichloride exposure groups (200, 400, and 800 µmol/L Al(3+)). The cell morphology was observed after 48 hours of exposure; the cell viability was measured by CCK-8 assay; total protein was extracted from the cells, and the expression of phospho-tau (p-tau) 181, 231, 262, and 396 and tau 5 was measured by Western blot.

RESULTSAs the Al(3+) concentration rose, the number of living SH-SY5Y cells decreased, and the synapses of the cells retracted. The viability of cells exposed to 800 µmol/L Al(3+) was significantly lower than that of the control group (P < 0.05). The 200, 400, and 800 µmol/L Al(3+) exposure groups showed significantly higher expression of p-tau 181, 231, and 396 and tau5 than the control group (P < 0.05), and the 800 µmol/L Al(3+) exposure group showed significantly higher expression of p-tau 262 than the control group (P < 0.05).

CONCLUSIONUnder the present experimental conditions, aluminum trichloride has toxic effect on SH-SY5Y cells and can lead to abnormal expression of p-tau 181, 231, and 396 and tau 5 at low Al(3+) concentration.

Aluminum Compounds ; toxicity ; Cell Line, Tumor ; Cell Survival ; drug effects ; Chlorides ; toxicity ; Humans ; Phosphorylation ; tau Proteins ; metabolism

In human prion diseases, phosphorylated-tau deposition has been described in a rare genetic form, Gerstmann-Straussler-Scheinker disease, but is not considered part of the neuropathological picture of Creutzfeldt-Jakob disease. To investigate the possible changes of tau and phosphorylated tau (Ser396/Ser404) in transmissible spongiform encephalopathies (TSEs), the expressions and transcriptions of above biological factors in the brain tissues of 263K- and 139A-infected hamsters were evaluated by Western blots and Real Time PCR, respectively, followed by quantitative analyses of immunoblot images and relative transcriptional levels compared with normal animals. The contents of total tau increased, but phosphorylated tau at Ser396 and Ser404 decreased, regardless of the types of scrapie agents and clinical incubations. Transcriptions of two tau isoforms were also markedly increased. These findings suggested that dephosphorylation of tau at Ser396/Ser404 was a illness-correlative phenomenon in TSEs. Alterations of tau and phosphorylated tau (Ser396/Ser404) were either intermediate or consequent events in TSE pathogenesis and proposed the potential linkage of these bioactive proteins with the pathogenesis of prion diseases.
Animals ; Blotting, Western ; Brain ; metabolism ; Cricetinae ; Gene Expression Regulation ; physiology ; Phosphorylation ; Polymerase Chain Reaction ; PrPSc Proteins ; pathogenicity ; Prion Diseases ; metabolism ; tau Proteins ; metabolism

OBJECTIVETo study the expression of tau-related protein in spinal cord of Chinese patients with Alzheimer's disease.

METHODSGallays-Braak stain and immunohistochemical study for tau protein (AT8) were carried out in the spinal cord tissue (T2, T8, T10, L2 and S2 segments) of 3 Chinese patients with Alzheimer's disease. Seven age-matched cases without evidence of dementia or neurologic disease were used as controls.

RESULTSNeurofibrillary tangles were identified in the neurons of anterior horn in 2 Alzheimer's disease cases but none was observed in the controls. Tau-positive axons and astroglia were detected in all Alzheimer's disease cases. Tau immunoreactivity in spinal cord of the patients correlated with that in brain tissue.

CONCLUSIONThe expression of tau-related protein is demonstrated in the spinal cord of Alzheimer's disease patients suggesting that axonal transport defect may play a role in the pathogenesis of Alzheimer's disease.

Aged ; Alzheimer Disease ; metabolism ; pathology ; Axonal Transport ; Axons ; metabolism ; pathology ; Humans ; Male ; Neurofibrillary Tangles ; metabolism ; pathology ; Phosphorylation ; Spinal Cord ; metabolism ; pathology ; tau Proteins ; metabolism