Gut dysbiosis in nonalcoholic fatty liver disease: pathogenesis, diagnosis, and therapeutic implications.

The incidence of nonalcoholic fatty liver disease (NAFLD) is increasing recently and has become one of the most common clinical liver diseases. Since the pathogenesis of NAFLD has not been completely elucidated, few effective therapeutic drugs are available. As the "second genome" of human body, gut microbiota plays an important role in the digestion, absorption and metabolism of food and drugs. Gut microbiota can act as an important driver to advance the occurrence and development of NAFLD, and to accelerate its progression to cirrhosis and hepatocellular carcinoma. Growing evidence has demonstrated that gut microbiota and its metabolites directly affect intestinal morphology and immune response, resulting in the abnormal activation of inflammation and intestinal endotoxemia; gut dysbiosis also causes dysfunction of gut-liver axis via alteration of bile acid metabolism pathway. Because of its composition diversity and disease-specific expression characteristics, gut microbiota holds strong promise as novel biomarkers and therapeutic targets for NAFLD. Intervening intestinal microbiota, such as antibiotic/probiotic treatment and fecal transplantation, has been a novel strategy for preventing and treating NAFLD. In this article, we have reviewed the emerging functions and association of gut bacterial components in different stages of NAFLD progression and discussed its potential implications in NAFLD diagnosis and therapy.

CXCL1 Clone Evolution Induced by the HDAC Inhibitor Belinostat Might Be a Favorable Prognostic Indicator in Triple-Negative Breast Cancer.

Triple-negative breast cancer (TNBC) is the most lethal subtype of breast cancer due to its lack of treatment options. Patients with TNBC frequently develop resistance to chemotherapy. As epigenetic-based antineoplastic drugs, histone deacetylase inhibitors (HDACis) have achieved particular efficacy in lymphoma but are less efficacious in solid tumors, and the resistance mechanism remains poorly understood. In this study, the GSE129944 microarray dataset from the Gene Expression Omnibus database was downloaded, and fold changes at the transcriptome level of a TNBC line (MDA-MB-231) after treatment with belinostat were identified. Gene Ontology (GO) and Kyoto Encyclopedia of Genes and Genomes (KEGG) pathway enrichment analyses were used to identify the critical biological processes. Construction and analysis of the protein-protein interaction (PPI) network were performed to screen candidate genes related to cancer prognosis. A total of 465 DEGs were identified, including 240 downregulated and 225 upregulated genes. The cytokine-cytokine receptor pathway was identified as being significantly changed. Furthermore, the expression of CXCL1 was implicated as a favorable factor in the overall survival of breast cancer patients. With in vitro approaches, we also showed that belinostat could induce the expression of CXCL1 in another 2 TNBC cell lines (BT-549 and HCC-1937). We speculate that belinostat-induced CXCL1 expression could be one of the results of the stress clone evolution of cells after HDACi treatment. These findings provide new insights into clone evolution during HDACi treatment, which might guide us to a novel perspective that various mutation-targeted treatments should be implemented during the whole treatment cycle.

Effect of spinal cord decellularized scaffold on the repair of spinal cord defects in rats / 解剖学报

Objective Exploring the effect of spinal cord decellularized scaffold on spinal cord defects and observing the behavior and regeneration of rats after operation. Methods The spinal cords of 30 SD rats were treated with 3% Triton X-100 and 2% sodium deoxycholate on oscillator. The cell residue and the spatial structure of the tissue were compared before and after treatment, in order to understand the tissue structure of the stent itself. 90 SD rats were randomly divided into control group, simple injury group and stent transplantation group. Excision of the spinal cord 9-10 segments in the simple injury group and the stent graft group the acellular scaffold was transplanted to the stent graft group. Behavioral scores were observed postoperatively. At 4, 8, and 12 weeks, the spinal cords of the injured part of the rats were taken for HE staining and immunofluorescence detection of nerve regeneration-related proteins. Results After decellularization of the spinal cord, the nerve cells and axons were completely removed, and the extracellular matrix of the spinal cord was preserved. Scanning electron microscopy revealed that the scaffold retained a certain porous network scaffold structure. In the experiment of decellularized scaffold in vivo, the Basso-Beattie-Bresnahan(BBB) score showed that the recovery of hindlimb motor function in rats with decellularized scaffolds was better than that in rats with simple injury. HE staining showed that the decellularized scaffold could fill the defect of the spinal cord segment and accelerate the repair process of the injured spinal cord. Immunofluorescence showed that there was a certain axonal regeneration in the injured part of the stent transplantation group. Conclusion The spinal cord decellularized scaffold retains the extracellular matrix and has a certain spatial structure, which can accelerate the process of spinal cord defect repair to a certain extent, and has a certain promoting effect on nerve regeneration.

Application of Weighted Gene Co-Expression Network Analysis to Explore the Key Genes in Alzheimer's Disease.

BACKGROUND: Weighted co-expression network analysis (WGCNA) is a powerful systems biology method to describe the correlation of gene expression based on the microarray database, which can be used to facilitate the discovery of therapeutic targets or candidate biomarkers in diseases. OBJECTIVE: To explore the key genes in the development of Alzheimer's disease (AD) by using WGCNA. METHODS: The whole gene expression data GSE1297 from AD and control human hippocampus was obtained from the GEO database in NCBI. Co-expressed genes were clustered into different modules. Modules of interest were identified through calculating the correlation coefficient between the module and phenotypic traits. GO and pathway enrichment analyses were conducted, and the central players (key hub genes) within the modules of interest were identified through network analysis. The expression of the identified key genes was confirmed in AD transgenic mice through using qRT-PCR. RESULTS: Two modules were found to be associated with AD clinical severity, which functioning mainly in mineral absorption, NF-κB signaling, and cGMP-PKG signaling pathways. Through analysis of the two modules, we found that metallothionein (MT), Notch2, MSX1, ADD3, and RAB31 were highly correlated with AD phenotype. Increase in expression of these genes was confirmed in aged AD transgenic mice. CONCLUSION: WGCNA analysis can be used to analyze and predict the key genes in AD. MT1, MT2, MSX1, NOTCH2, ADD3, and RAB31 are identified to be the most relevant genes, which may be potential targets for AD therapy.

MIPPO and ORIF for the treatment of elderly proximal humerus fractures of type Neer II:a case control study / 中国骨伤

<p><b>OBJECTIVE</b>To compare the clinical efficacy of minimally invasive percutaneous plate osteosynthesis(MIPPO)and open reduction and internal fixation (ORIF) in treating senile NEER IIproximal humerus fractures.</p><p><b>METHODS</b>From March 2014 to March 2016, 46 elderly patients with Neer II proximal humerus fractures were retrospectively reviewed. Among them, 20 patients in MIPPO group included 9 males and 11 females with an average age of (70.4±4.4) years old; while 26 patients in ORIF group included 11 males and 15 females with an average age of (70.9±4.0) years old. The length of hospital stay, times of fluoroscopy, beginning time of function rehabilitation, healing time of fracture, Constant Murley score of the shoulder joint at 3, 6, 12 months after operation and complications were observed and compared.</p><p><b>RESULTS</b>All patients were followed up for 12 to 24 months with an average of 16.8±3.7. The healing time of fracture, beginning time of function rehabilitation in MIPPO group were(13.0±0.8) weeks, (3.0±0.9) days respectively and shorter than those in ORIF group which were (13.8±1.4) weeks and(6.8±1.3) days. The times of fluoroscopy in MIPPO group was 19.2±3.7 and more than that in ORIF group which was 12.1±3.4. At 3 and 6 months after operation, Constant Murley score in MIPPO group were 81.3±3.9, 86.6±5.4 and more than that in ORIF group which were 69.5±6.6, 80.5±6.7. There were no differences between two groups in the length of hospital stay, Constant Murley score at 12 months after operation and grading at the final follow-up. There was one fracture redisplacement in each group. And 1 case of axillary nerve injury in MIPPO group, 2 cases of delayed union in ORIF group. No incision infection, screw loosening or plate break was found.</p><p><b>CONCLUSIONS</b>MIPPO and ORIF are both effective in treating Neer II proximal humeral fractures. MIPPO technique has the advantages of faster recovery, earlier rehabilitative exercise and better shoulder function. The disadvantages are more exposure to radiationd and the possibility of axillary nerve injure.</p>

The lncRNA H19 mediates breast cancer cell plasticity during EMT and MET plasticity by differentially sponging miR-200b/c and let-7b.

Metastasis is a multistep process by which tumor cells disseminate from their primary site and form secondary tumors at a distant site. The pathophysiological course of metastasis is mediated by the dynamic plasticity of cancer cells, which enables them to shift between epithelial and mesenchymal phenotypes through a transcriptionally regulated program termed epithelial-to-mesenchymal transition (EMT) and its reverse process, mesenchymal-to-epithelial transition (MET). Using a mouse model of spontaneous metastatic breast cancer, we investigated the molecular mediators of metastatic competence within a heterogeneous primary tumor and how these cells then manipulated their epithelial-mesenchymal plasticity during the metastatic process. We isolated cells from the primary mammary tumor, the circulation, and metastatic lesions in the lung in TA2 mice and found that the long noncoding RNA (lncRNA) H19 mediated EMT and MET by differentially acting as a sponge for the microRNAs miR-200b/c and let-7b. We found that this ability enabled H19 to modulate the expression of the microRNA targets Git2 and Cyth3, respectively, which encode regulators of the RAS superfamily member adenosine 5'-diphosphate (ADP) ribosylation factor (ARF), a guanosine triphosphatase (GTPase) that promotes cell migration associated with EMT and disseminating tumor cells. Decreasing the abundance of H19 or manipulating that of members in its axis prevented metastasis from grafts in syngeneic mice. Abundance of H19, GIT2, and CYTH3 in patient samples further suggests that H19 might be exploited as a biomarker for metastatic cells within breast tumors and perhaps as a therapeutic target to prevent metastasis.

Aspirin regulation of c-myc and cyclinD1 proteins to overcome tamoxifen resistance in estrogen receptor-positive breast cancer cells.

Tamoxifen is still the most commonly used endocrine therapy drug for estrogen receptor (ER)-positive breast cancer patients and has an excellent outcome, but tamoxifen resistance remains a great impediment to successful treatment. Recent studies have prompted an anti-tumor effect of aspirin. Here, we demonstrated that aspirin not only inhibits the growth of ER-positive breast cancer cell line MCF-7, especially when combined with tamoxifen, but also has a potential function to overcome tamoxifen resistance in MCF-7/TAM. Aspirin combined with tamoxifen can down regulate cyclinD1 and block cell cycle in G0/G1 phase. Besides, tamoxifen alone represses c-myc, progesterone receptor (PR) and cyclinD1 in MCF-7 cell line but not in MCF-7/TAM, while aspirin combined with tamoxifen can inhibit the expression of these proteins in the resistant cell line. When knocking down c-myc in MCF-7/TAM, cells become more sensitive to tamoxifen, cell cycle is blocked as well, indicating that aspirin can regulate c-myc and cyclinD1 proteins to overcome tamoxifen resistance. Our study discovered a novel role of aspirin based on its anti-tumor effect, and put forward some kinds of possible mechanisms of tamoxifen resistance in ER-positive breast cancer cells, providing a new strategy for the treatment of ER-positive breast carcinoma.

Targeting colorectal cancer cells by a novel sphingosine kinase 1 inhibitor PF-543.

In this study, we showed that PF-543, a novel sphingosine kinase 1 (SphK1) inhibitor, exerted potent anti-proliferative and cytotoxic effects against a panel of established (HCT-116, HT-29 and DLD-1) and primary human colorectal cancer (CRC) cells. Its sensitivity was negatively associated with SphK1 expression level in the CRC cells. Surprisingly, PF-543 mainly induced programmed necrosis, but not apoptosis, in the CRC cells. CRC cell necrotic death was detected by lactate dehydrogenase (LDH) release, mitochondrial membrane potential (MMP) collapse and mitochondrial P53-cyclophilin-D (Cyp-D) complexation. Correspondingly, the necrosis inhibitor necrostatin-1 largely attenuated PF-543-induced cytotoxicity against CRC cells. Meanwhile, the Cyp-D inhibitors (sanglifehrin A and cyclosporin A), or shRNA-mediated knockdown of Cyp-D, remarkably alleviated PF-543-induced CRC cell necrotic death. Reversely, over-expression of wild-type Cyp-D in HCT-116 cells significantly increased PF-543's sensitivity. In vivo, PF-543 intravenous injection significantly suppressed HCT-116 xenograft growth in severe combined immunodeficient (SCID) mice, whiling remarkably improving the mice survival. The in vivo activity by PF-543 was largely attenuated when combined with the Cyp-D inhibitor cyclosporin A. Collectively, our results demonstrate that PF-543 exerts potent anti-CRC activity in vitro and in vivo. Mitochondrial programmed necrosis pathway is likely the key mechanism responsible for PF-543's actions in CRC cells.

Gabarapl1 mediates androgen-regulated autophagy in prostate cancer.

Autophagy plays an important role in prostate cancer development. It promotes tumor cell survival and was found to be associated with androgen pathway. In the present study, we found that GABA(A) receptor-associated protein like 1 (Gabarapl1), a ubiquitin-like modifier, participates in the regulation of autophagy. Gabarapl1 is transcriptionally regulated by androgen receptor (AR) and has a repressive role in autophagy. Androgen deprivation downregulates Gabarapl1 in an AR dependent manner, resulting in the increase of autophagy flux. Elevated Gabarapl1 also represses the proliferation of prostate cancer cells. In summary, our study provides evidence to show that Gabarapl1 is a mediator involved in androgen-regulated autophagy process.

Coseeded Schwann cells myelinate neurites from differentiated neural stem cells in neurotrophin-3-loaded PLGA carriers.

Biomaterials and neurotrophic factors represent promising guidance for neural repair. In this study, we combined poly-(lactic acid-co-glycolic acid) (PLGA) conduits and neurotrophin-3 (NT-3) to generate NT-3-loaded PLGA carriers in vitro. Bioactive NT-3 was released stably and constantly from PLGA conduits for up to 4 weeks. Neural stem cells (NSCs) and Schwann cells (SCs) were coseeded into an NT-releasing scaffold system and cultured for 14 days. Immunoreactivity against Map2 showed that most of the grafted cells (>80%) were differentiated toward neurons. Double-immunostaining for synaptogenesis and myelination revealed the formation of synaptic structures and myelin sheaths in the coculture, which was also observed under electron microscope. Furthermore, under depolarizing conditions, these synapses were excitable and capable of releasing synaptic vesicles labeled with FM1-43 or FM4-64. Taken together, coseeding NSCs and SCs into NT-3-loaded PLGA carriers increased the differentiation of NSCs into neurons, developed synaptic connections, exhibited synaptic activities, and myelination of neurites by the accompanying SCs. These results provide an experimental basis that supports transplantation of functional neural construction in spinal cord injury.

Amplifications of NCOA3 gene in colorectal cancers in a Chinese population.

AIM: To investigate the copy number variation of NACO3 gene in colorectal cancer (CRC) and its correlation with tumor progression. METHODS: A total of 142 samples of case-matched CRC tissues and adjacent normal tissues were obtained from patients undergoing bowel resection. Quantitative real-time polymerase chain reaction method was used to investigate the copy number variations of NCOA3 as well as gene expression in the collected tissues. RESULTS: Copy number gains of NCOA3 were detected in 39 CRC samples (27.5%) and were correlated with tumor progression (χ2 = 6.42, P = 0.0112). Moreover, there was a positive correlation between copy number gain and mRNA over-expression of NCOA3 in CRCs (P = 0.0023). Expression level of NCOA3 mRNA was also enhanced in the CRC samples with unaltered copy numbers (3.85 ± 1.23 vs. 2.71 ± 0.64, P < 0.01). CONCLUSION: Sporadic colorectal cancers exhibit different mechanisms of NCOA3 regulation.

Magnetic stimulation influences injury-induced migration of white matter astrocytes.

This study investigates the effects and underlying mechanism of magnetic stimulation on injury-induced migration of white matter astrocytes. Twenty-four adult healthy SD rats were selected to inject 0.5 ml of 1% ethidium bromide (EB) in PBS into the dorsal spinal cord funiculus on the left side at the T10-11 level to make located spinal cord injury models. Then they were randomly divided into four groups (A, B, C, and D). Groups A, B, C, and D were exposed to 1 Hz pulsed magnetic stimulation underwent 5-min sessions on 14 consecutive days at the following levels: 0T (Group A) 1.9x40% T (Group B); 1.9x80% T (Group C); 1.9x100% T (Group D). On day 14 after stimulation, the rats were killed and the expression of glial fibrillary acidic protein (GFAP), microtubule associated protein-2 (MAP-2), extracellular signal-regulated kinase1/2 (ERK1/2), and the volume of holes were detected with immunohistochemistry. Quantitative analysis of the expression of GFAP, MAP-2, and ERK1/2 were performed with the image analysis system. With the increase of magnetic stimulation intensity, the volume of hole decreased at day 14 (P<0.05). In lesion areas, the expression of GFAP and ERK1/2 could be seen, while that of MAP-2 did not change before and after magnetic stimulation. Significant difference was revealed in the expression of GFAP, ERK1/2 among the four groups. It was significantly higher in the magnetic stimulation groups than that in the control group (P<0.05). After magnetic stimulation, astrocytes migrated into the hole. U0126, a potent and selective MEK1/2 inhibitor, inhibited up-regulation of pERK1/2 which was stimulated by magnetic stimulation. These data indicate that magnetic stimulation increases the migratory capacity of reactive white matter astrocytes in the injured center nervous system, which may be associated with activation of MEK1,2/ERK mitogenic pathway.

Spinal cord injury-induced astrocyte migration and glial scar formation: effects of magnetic stimulation frequency.

The effects of magnetic stimulation on spinal cord injury-induced migration of white matter astrocytes were studied using an established animal model. Ethidium bromide was injected into the dorsal spinal cord funiculus of adult Sprague-Dawley rats on the left side at T10-11. Animals then received 1.52 Tesla-pulsed magnetic stimulation for 5 min at different frequencies (0-20 Hz) for 14 consecutive days. Selected animals received the non-competitive MEK1/2 inhibitor U0126 (10 microM), prior to stimulation at 10 Hz. Lesion volumes were measured in hematoxylin/eosin-stained sections. Expression of glial fibrillary acidic protein (GFAP), microtubule associated protein-2 (MAP-2) and extra-cellular signal-regulated kinasel/2 (ERK1/2) near the epicenter of injury was examined by Western blotting with quantification using an image analysis system. Lesion volumes decreased and GFAP and p-ERK1/2 expression increased with increasing magnetic stimulation frequency (0-10 Hz). MAP-2 expression was not affected at any frequency. Pretreatment with U0126 reduced GFAP and ERK1/2 expression and increased lesion volumes in response to stimulation at 10 Hz. It is concluded that magnetic stimulation increases the migration of astrocytes to spinal cord lesions. Activation of the ERK1/2 signaling pathway is proposed to mediate astrocyte migration and glial scar formation in response to spinal cord injury.

[The effects of GABAergic neurotransmitters and GABAA receptors on the auditory afferent pathway in the brainstem analyzed by optical recording].

AIM: To explore the influence of GABAergic neurotransmitters and GABAA receptors on the auditory afferent impulses recorded in the brainstem evoked by electro-stimulation. METHODS: Brainstem slices were prepared using ddy/ddy mice of postnatal 0-5th days. The brainstem slices were stained with a voltage-sensitive dye(NK3041). The cut end of the vestibulocochlear nerve (nVIIIth) connected with slices was stimulated by a tungsten electrode, a 16 x 16 pixels silicon photodiode array apparatus was used to record the optical mapping from auditory brainstem slices. The data were analyzed by ARGUS-50/PDA software. RESULTS: The spatial-temporal patterns of the excitatory propagation from the vestibulocochlear nerve (nVIIIth) to cochlear nucleus and vestibular nucleus were displayed with multiple-sites optical recording. The optical signal coming from one pixel consisted of a fast spike-like response and a following slow response. Inhibitory neurotransmitter GABA decreased the fast spike-like response and following slow response of evoked optical signals, while an antagonist BMI against GABAA receptors increased the both responses. CONCLUSION: A 16 x 16 pixel silicon photodiode array apparatus can be used to record multiple-sites optical mapping evoked by electro-stimulation to the cut end of the vestibulocochlear nerve. The every optical signal consists of both presynaptic and postsynaptic elements. Inhibitory neurotransmitter GABA and an antagonist BMI of GABAA receptors can modulate the excitatory propagation of evoked optical signals.

Effect and mechanism of ligustrazine on Th1/Th2 cytokines in a rat asthma model.

Ligustrazine is an alkaloid isolated from the rhizome of Chuanxiong (Ligusticum chuanxiong Hort), which is known to possess antioxidant, anti-inflammatory, anti-fibrosis and immunomodulative effects. It is used clinically to treat asthma as an assistant therapy of glucocorticoid. The purpose of this study was to explore the effects of intraperitoneal ligustrazine on Th1/Th2 cytokines in a rat asthma model and the underlying mechanism. SD rats were sensitized and challenged with ovalbumin (OVA) to establish an asthmatic model. Within 24 hours after the last ovalbumin challenge, changes in airway histology were observed. The concentrations of IL-4 and IFN-gamma in bronchoalveolar lavage fluid (BALF) were measured by enzyme linked immunosorbent assay (ELISA). The protein expressions of GATA-3 and T-bet in lung were measured by Western blot. The results showed that an increase of Th2 cytokine and an inhibition of Th1 cytokine were accompanied by an increased expression of GATA-3 protein and a decreased expression of T-bet protein in rat asthmatic airways compared to those in normal control group. Intraperitoneal ligustrazine administration could significantly lower the level of IL-4 in BALF and the expression of GATA-3 protein in lung and also increase the level of IFN-gamma and T-bet in asthmatic rats, resulting in a decreased percentage of eosinophils (EOS) in BALF and ameliorated airway inflammatory cell infiltration. In conclusion, ligustrazine inhibits OVA induced airway inflammation by modulating key master switches GATA-3 and T-bet that result in reversing the Th2 cytokine patterns in asthma.

Integrin beta(1A) upregulates p27 protein amount at the post-translational level in human hepatocellular carcinoma cell line SMMC-7721.

Integrins mediate many fundamental cellular processes by binding to components of the extracellular matrix. We showed previously that integrin beta(1A) could inhibit cell proliferation. Integrin beta(1A) stimulated the promoter activity of p21(cip1) and enhanced its transcription in SMMC-7721 cells. In this study, we demonstrated that integrin beta(1A) upregulated p27(kip1) at the post-translational level in SMMC-7721 cells. Our results showed that integrin beta(1A) increased the p27 protein amount, both in cytoplasm and nucleus, but did not affect the p27 mRNA amount. Cycloheximide treatment experiment revealed that the half-life of p27 protein was prolonged in integrin beta1A overexpressing cells, indicating that integrin beta(1A) inhibited the degradation of p27 protein. Our data also provided evidence that both the proteasome and calpain were involved in the degradation of p27 protein in SMMC-7721 cells. Integrin beta(1A) decreased the Skp2 expression and repressed the activity of calpain during G1 phase in SMMC-7721 cells. Taken together, these results indicated that integrin beta(1A) might upregulate the protein amount of p27 through repressing Skp2-dependent proteasome degradation and calpain-mediated proteolysis in SMMC-7721 cells.

Tau becomes a more favorable substrate for GSK-3 when it is prephosphorylated by PKA in rat brain.

Microtubule-associated protein tau is abnormally hyperphosphorylated in Alzheimer's disease (AD) and other tauopathies and is believed to lead to neurodegeneration in this family of diseases. Here we show that infusion of forskolin, a specific cAMP-dependent protein kinase A (PKA) activator, into the lateral ventricle of brain in adult rats induced activation of PKA by severalfold and concurrently enhanced the phosphorylation of tau at Ser-214, Ser-198, Ser-199, and or Ser-202 (Tau-1 site) and Ser-396 and or Ser-404 (PHF-1 site), which are among the major abnormally hyperphosphorylated sites seen in AD. PKA activation positively correlated to the extent of tau phosphorylation at these sites. Infusion of forskolin together with PKA inhibitor or glycogen synthase kinase-3 (GSK-3) inhibitor revealed that the phosphorylation of tau at Ser-214 was catalyzed by PKA and that the phosphorylation at both the Tau-1 and the PHF-1 sites is induced by basal level of GSK-3, because forskolin activated PKA and not GSK-3 and inhibition of the latter inhibited the phosphorylation at Tau-1 and PHF-1 sites. Inhibition of cdc2, cdk5, or MAPK had no significant effect on the forskolin-induced hyperphosphorylation of tau. Forskolin inhibited spatial memory in a dose-dependent manner in the absence but not in the presence of R(p)-adenosine 3',5'-cyclic monophosphorothioate triethyl ammonium salt, a PKA inhibitor. These results demonstrate for the first time that phosphorylation of tau by PKA primes it for phosphorylation by GSK-3 at the Tau-1 and the PHF-1 sites and that an associated loss in spatial memory is inhibited by inhibition of the hyperphosphorylation of tau. These data provide a novel mechanism of the hyperphosphorylation of tau and identify both PKA and GSK-3 as promising therapeutic targets for AD and other tauopathies.

[Effect of calpain on the degradation of tau protein in rat brain cortex extracts].

Calpain is a calcium-activated protease and has two ubiquitously distributed mammalian isoforms, namely calpain 1 (calpain I, mu-calpain and CAPN1) and calpain 2 (calpain II, m-calpain and CAPN2). Calpains regulate the function of many proteins by limited proteolysis. To determine the nature of different subtypes of calpain on degradation of microtubule-associated protein tau, the rat cortex extracts were incubated with 0.2 mmol/L, 1 mmol/L, 3 mmol/L and 5 mmol/L of CaCl(2 )for 15 min at 37 degrees C, respectively, and it was found that Ca(2+) treatment at concentrations 1-5 mmol/L led to significant proteolysis of the tau protein and this degradation was blocked by calpain inhibitor, calpeptin. In addition, when the extracts containing 1 mmol/L CaCl(2 )were treated with mu-calpain inhibitor (0.05 micromol/L of calpastatin) or m-calpain inhibitor (100 micromol/L calpain inhibitor IV) or both, the Ca(2+)-induced degradation of tau protein was blocked to about 8.6% 92.5% and 97.8% compared with the group with 1 mmol/L CaCl(2), respectively. These data suggest that both mu-calpain and m-calpain in brain cortex extracts are activated by Ca(2+) and both of them degraded tau protein, although, m-calpain plays a more important role in proteolysis of the tau protein.

Alzheimer-like phosphorylation of tau and neurofilament induced by cocaine in vivo.

AIM: To explore the relationship between cocaine-induced cyclin-dependent kinase-5 (CDK5) overexpression or overactivation and Alzheimer-like hyperphosphorylation of cytoskeletal protein. METHODS: Cocaine was injected (ip, 20 mg/kg/d) into rats and the phosphorylation of neuronal cytoskeletal proteins was measured by Western blotting. RESULTS: The levels of phosphorylated tau at PHF-1 epitope and phosphorylated neurofilament determined by SMI31 were elevated in rat brain hippocampus, cortex, and caudatoputamen on d 8 and d 16 after the injection of cocaine, when compared with saline control rat at the same brain regions. On the other hand, the levels of tau non-phosphorylated at tau-1 site and non-phosphorylated neurofilament determined by SMI32 were decreased in same brain regions at the same time points examined. No significant difference of phosphorylated tau and neurofilament at those epitopes was seen on d 4. Although cocaine injection could induce significant hyperphosphorylation of neuronal cytoskeletal proteins, the overexpression of CDK5 and p35 was not detected. CONCLUSION: Peritoneal injection of cocaine induces Alzheimer-like hyperphosphorylation of tau and neurofilament in rat brain, and the effect may be not relevant to an increase in overexpression or overactivation of CDK5.

[Relationship between amyloid beta-protein and oxidative stress and the protective role of pituitary adenylate cyclase activating polypeptide against oxidative stress induced damage on neuro-2a cells].

AIM: To observe the relationship between amyloid beta-protein (Abeta) and oxidative stress and the protective role of pituitary adenylate cyclase activating polypeptide (PACAP, PACAP-27) against damage induced by oxidative stress (H2O2) in neurem-2a cells. METHODS: With cultured neuro-2a cells the cell survival and apoptosis were measured by MTT assay, Hoechest33258 staining, DNA ladder and the percentage of small DNA fragment. RESULTS: Concentration-dependent toxicity was induced with H2O2 treatment for 24 h. The neurotoxicity of H2O2 was increased by about 10 times with cotreatment neurons with amyloid beta-protein fragment 25-35 (Abeta(25-35)). While decrease the percentage of small DNA fragmentation the cell survival was increased with co-treatment with PACAP-27(which were added to the culture everyday). The effect of PACAP was not reversed with antagonist of PACAP receptor, PACAP(6-27). CONCLUSION: Abeta and H2O2 can promote each other's neurotoxicity. Cultured neurons were protected by PACAP27 from the neurotoxicity of H2O2 but not through the activation of PACAP-27 receptor.