Effects of analog P165 of amyloid precursor protein 5-mer peptide on learning, memory and brain insulin receptors in the rat model of cognitive decline.

We aim to study the therapeutic efficacy of analog P165 of amyloid precursor protein 5-mer peptide in streptozotocin (STZ)-induced cognitive decline model. Rats were divided into four groups: control, STZ, STZ+P165, and STZ+rosiglitazone (RSG). STZ model was established by intracerebroventricular injection of STZ. Three weeks following surgery, rats received daily gavage administration of distilled water (control and STZ groups), P165 (STZ+P165), or RSG (STZ+RSG) for four consecutive weeks. Learning and memory abilities were assessed with the Morris water maze test. Insulin-like growth factor-1 (IGF-1) was detected by ELISA. Expressions of insulin receptor-ß (IR-ß), insulin receptor substrate-1 (IRS-1), serine/threonine kinase (Akt), and phosphorylation of CREB (p-CREB) were observed by immunohistochemistry. Both P165 and RSG significantly reduced the escape latency relative to the STZ group (P165, P < 0.05; RSG, P < 0.01). STZ model rats had reduced levels of IGF-1 relative to control, and this deficit was attenuated in the STZ+P165 group (P < 0.01). IR and IRS-1 were elevated in STZ rats, and these levels were restored to near control in the STZ+P165 and STZ+RSG groups (P < 0.01). Our findings demonstrate that P165 and RSG improved hippocampus-dependent spatial learning and memory in STZ rats by regulating the insulin signaling pathway.

Comparison of physiological and yield traits between purple- and white-pericarp rice using SLs.

Five physiological and eleven yield traits of two pairs of sister lines generated from a high generation with similar genetic background (SLs) for purple pericarp were investigated to explore the reasons behind low-yield production of colored rice. Of the five physiological traits examined, except grain anthocyanin content, there were generally similar trends between the P (purple-pericarp) lines and the corresponding W (white-pericarp) lines over two seasons (in the year 2009 and 2010 separately). The results demonstrated that the chlorophyll content of flag leaves, the net photosynthetic rate of flag leaves, and the grain anthocyanin content could be easily influenced by the environment. The physiological functions of the traits for the P lines were more active than those of the corresponding W lines in the year 2010. The grain anthocyanin content of the P lines was much greater in the year 2010 than in the year 2009 during the growth period. The investigation of yield traits revealed that the P lines had reduced 1000-grain weight, yield per plot and grain/brown rice thickness compared to the W lines. A difference comparison of these traits and a source-sink and transportation relationship analysis for these SLs suggested that small sink size was a key reason behind yield reduction of purple pericarp rice.

Amyloid precursor protein 17-mer peptide ameliorates hippocampal neurodegeneration in ovariectomized rats.

Amyloid precursor protein 17-mer peptide (APP 17-mer peptide) is an active fragment of amyloid precursor protein (APP) in the nervous system that mediates various neuronal activities and functions. Estrogen deprivation during menopause disproportionately increases the risk of many neurodegenerative diseases, including Alzheimer's disease (AD). Currently, therapeutic approaches to treat Alzheimer's disease are less than effective. We have previously shown that APP 17-mer peptide participates in neuronal function in aged-hippocampal neurons. In this study, we investigate the effects of estrogen and APP 17-mer peptide on hippocampal neurodegeneration in ovariectomized rats. The results showed that decreases in learning and memory function in ovariectomized rats were associated with degenerative changes in hippocampal neurons. Estrogen deprivation also enhances apoptotic cell death and decreases expression of the anti-apoptotic protein Bcl-2. Administration of APP 17-mer peptide ameliorates changes associated with estrogen deprivation without affecting estrogen levels. These results indicate that APP 17-mer peptide may prevent neurodegeneration caused by estrogen deficiency. Our findings also suggest that estrogen deficiency-induced neurodegeneration is regulated by activation of an intracellular "cross talk" signaling pathway, connecting neurotrophins with APP 17-mer peptide.

A novel neurotrophic peptide: APP63-73.

The objective of this study was to find out which N-terminal segment/s of amyloid precursor protein (APP) has any neurotrophic properties, since soluble APP-alpha (sAPP-alpha) has neurotrophic effects. We investigated neurotrophic properties of eight peptide segments of N-terminal APP. The APP63-73 was able to enhance neuronal growth; augment axonal and cell body growth in human neuroblastoma cell line, SH-SY5Y. Neurotrophic effects of chronic APP63-73 treatment were assessed in vivo using streptozotocin-induced diabetes and ovariectomized rats. Thus, this study demonstrated that APP63-73 peptide has neurotrophic effects both in vivo and in vitro.

[Cloning and expression of human single-chain Fv antibody against amyloid beta peptide involved in Alzheimer's disease].

OBJECTIVE: To screen out the specific antibody clones against amyloid beta peptide 40, and clone the antibody gene and express it in a bacterial system, so as to provide a solid basis for novel diagnostic and therapeutic methods for Alzheimer's Disease. METHODS: beta amyloid peptide 40 was bound on the solid surface of Nunc plates as antigen to screen the binding clones from a phage-display human single-chain Fv antibody library. After five rounds of bio-panning, the host E. coli TG1 was infected with eluted filamentous phage from the last turn of selection. 55 well-separated colonies were picked randomly from the plates and the specific positive clones were identified by ELISA test. The single-chain Fv antibody gene was sequenced and their amino acids sequence was deduced. The scFv antibody gene was sub-cloned into a protokayotic expression vector pGEX-6P-1 and transformed into bacteria strain BL21 to express the glutathione-S-transferase (GST) fusion single-chain antibody. RESULTS: ELISA test showed that 33 of the 55 clones could bind amyloid beta peptide 40 and 10 of the 33 clones could be inhibited by amyloid beta peptide 40 itself to below 50% of its original binding activities. Five of the 10 clones could also be inhibited by amyloid beta peptide 1-16 to the same level, which meant that the binding epitope of the antibody from the 5 clones was between first to sixteenth amino acids at amino-end of amyloid beta peptide 40. DNA sequencing data demonstrated that the gene of the single-chain antibody specifically against amyloid beta peptide 40 was consisted of 768 bp and the deduced amino acids sequence confirmed its typical antibody structure. The complement determinant regions and framework regions were discriminated empirically. After cloning the antibody gene into a protokayotic system, the GST fusion antibody was expressed as the expected size. CONCLUSIONS: After five rounds of bio-panning and subsequently serial ELISA testing, the specific antibody clones against amyloid beta peptide 40 were screened out successfully. The antibody gene DNA sequence and amino acids sequence were analyzed and confirmed. The fusion antibody was expressed as expected in the bacterial system.

Effect of amyloid precursor protein 17mer peptide on microtubule structure and tau protein hyperphosphorylation in hippocampal neurons of experimental diabetic mice.

The objective of this study was to investigate whether microtubular structure changes and tau protein hyperphosphorylation exist in hippocampal neurons of experimental diabetic mice, and to study the effect of amyloid precursor protein 17mer peptide. The results showed that the microtubules of hippocampal neurons of diabetic mice manifested prominent signs of fragmentation and dissolution, tau protein is hyperphosphorylated at Ser 199/Thr 202 sites, enzymes related to the phosphorylation and dephosphorylation of tau protein were diminished. The administration of amyloid precursor protein 17mer peptide could ameliorate the foregoing changes in diabetic mice. These results indicated that protein synthesis in the brain tissue of diabetic mice decreased. Amyloid precursor protein 17mer peptide acted as a neuroprotective agent that globally alleviates the disturbances due to impaired energy metabolism in diabetic mice.

[The effect of jiunaoyizhi capsul on signal transduction pathway of SY5Y cell lines].

OBJECTIVE: To observe the effect of Jiunaoyizhi capsul on the signal transduction pathway of SY5Y cell lines and explore the mechanism of the function of the capsul's enhancing neuronal growth. METHOD: Human neuroblastoma was used as cell models and they were divided into control group and experimental group. Supernatant of cell lysate was taken and immunoprecipitation was done with antibodies to proteins related to signal transduction pathway, and the immunoprecipitates were analyzed by Western blotting. RESULT: After treatment with Jiunaoyizhi capsul, expression of Akt/PKB, CREB, P-CREB was clearly increased and expression of cytochrome C decreased more than the control group. CONCLUSION: Jiunaoyizhi capsul can promote expression of some proteins related with signal transduction pathway in SY5Y cell lines. Mechanism of Jiunaoyizhi capsul's enhancing neuronal growth is relevant to expression of some proteins in signal transduction pathway.