Intracerebral-ventricular (ICV) injection of streptozotocin (STZ) induces an insulin-resistant brain state that may underlie the neural pathogenesis of sporadic Alzheimer disease (AD). Our previous work showed that prior ICV treatment of glucagon-like peptide-1 (GLP-1) could prevent STZ-induced learning memory impairment and tau hyperphosphorylation in the rat brain. The Chinese herbal medicine geniposide is known to relieve symptoms of type 2 diabetes. Because geniposide is thought to act as a GLP-1 receptor agonist, we investigated the potential therapeutic effect of geniposide on STZ-induced AD model in rats. Our result showed that a single injection of geniposide (50 μM, 10 μL) to the lateral ventricle prevented STZ-induced spatial learning deficit by about 40% and reduced tau phosphorylation by about 30% with Morris water maze test and quantitative immunohistochemical analysis, respectively. It has been known that tau protein can be phosphorylated by glycogen synthase kinase-3 (GSK3) and STZ can increase the activity of GSK3β. Our result with Western blot analysis showed that central administration of geniposide resulted in an elevated expression of GSK3β(pS-9) but suppressed GSK3β(pY-216) indicating that geniposide reduced STZ-induced GSK3β hyperactivity. In addition, ultrastructure analysis showed that geniposide averted STZ-induced neural pathology, including paired helical filament (PHF)-like structures, accumulation of vesicles in synaptic terminal, abnormalities of endoplasmic reticulum (ER) and early stage of apoptosis. In summary, our study suggests that the water soluble and orally active monomer of Chinese herbal medicine geniposide may serve as a novel therapeutic agent for the treatment of sporadic AD.

PurposeThe current study was undertaken to investigate whether glaucoma affects the sleep quality and whether there is any difference between patients with primary glaucoma (primary open angle glaucoma, POAG and primary angle-closure glaucoma, PACG) and healthy subjects, using a validated self-rated questionnaire, the Pittsburgh Sleep Quality Index (PSQI).MethodsThe sleep quality of patients with POAG and PACG was tested against normal controls. Subjects were divided into three sub-groups according to age. Differences in the frequency of sleep disturbances (PSQI score >7) were assessed. The differences of sleep quality within the three groups and within the POAG group depending on the patients’ intraocular pressure (IOP) and impairment of visual field (VF) were also studied.Results92 POAG patients, 48 PACG patients and 199 controls were included. Sleep quality declined with age in control and POAG group (tendency chi-square, P<0.05). The prevalence of sleep disturbances was higher in POAG and PACG group than in the control group, the differences were statistically significant. The prevalence of sleep disturbances was higher in patients with PACG, compared to POAG patients in the age interval of 61–80. In POAG group, the ratio of patients with sleep disorders increased with augmented impairment of VF, but the differences were not statistically significant (χ2-test, P>0.05). No significant differences were found in POAG group between patients with a highest IOP in daytime and at nighttime (χ2-test, P>0.05).ConclusionsThe prevalence of sleep disorders was higher in patients with POAG and PACG than in controls. PACG patients seemed to have a more serious problem of sleep disorders than POAG patients between 61 to 80 years old. No correlation was found between the prevalence of sleep disorders and impairment of VF or the time when POAG patients showed a highest IOP.

5034 Introduction: The IRE1α-XBP1 pathway, a key component of the endoplasmic reticulum (ER) stress response, is considered to be a critical regulator for survival of multiple myeloma (MM) cells. Because of the production of abundant immunoglobulins and cytokines, MM cells need to survive under chronic ER stress. In addition, MM cells are located in the bone marrow milieu, which is usually considered hypoxic compared to other organs. Therefore, MM cells need to possess mechanisms to protect against ER stress. Among the unfolded protein responses in MM cells, the IRE1α-XBP1 pathway has been implicated in the proliferation and survival of MM cells to a greater extent than in those of monoclonal gammopathy of undetermined significance or normal plasma cells. It has been reported to be a prognostic factor and could be a target for immunotherapy or chemotherapy. Based on previous reports, it is proposed that an inhibitor of IRE1α-XBP1 activation should be a potent therapeutic agent for MM. Therefore, the availability of small molecule inhibitors targeting this pathway would offer a new therapeutic strategy for MM. Here, we screened small molecule inhibitors of ER stress-induced XBP1 activation, and identified toyocamycin from a culture broth of an Actinomycete strain. Materials & Methods: First, we evaluated the mechanism of toyocamycin-induced inhibition of IREα activity, with focused on its kinase activity, endonuclease activity, and other unfolded protein responses. Next, the activity of toyocamycin was evaluated on MM cell lines and other tumor cells about IRE1α activity and cytotoxicity. Similarly, 9 primary MM cells were tested. Finally, the in vivo efficacy of toyocamycin was evaluated in a human MM xenograft model. Results & Discussion: Toyocamycin was shown to suppress thapsigargin-, tunicamycin- and 2-deoxyglucose-induced XBP1 mRNA splicing in HeLa cells without affecting ATF6 and PERK activation. Furthermore, although toyocamycin was unable to inhibit IRE1 a phosphorylation, it prevented IRE1α-induced XBP1 mRNA cleavage in vitro. Thus, toyocamycin is an inhibitor of IRE1α-induced XBP1 mRNA cleavage. Next, we examined the effect of toyocamycin on MM cells. Most MM cell lines have activated XBP1 protein expression, represented as the overexpression of spliced XBP1 isoform, whereas non-MM cells including other hematological and solid tumor cells have little activation of XBP1. Toyocamycin inhibited constitutive activation of XBP1 in MM cell lines without affecting IRE1α phosphorylation. This inhibition occurred within 6 hours after exposure to 30 nM toyocamycin. We then evaluated the growth inhibitory effect of toyocamycin on 7 MM cell lines with high spliced-XBP1 expression, 3 MM cell lines with low spliced-XBP1 expression, and 4 non-MM cell lines as assessed by MTS assay. All MM cells with high spliced-XBP1 expression showed remarkable decline in cellular viability at 30 nM or higher concentrations of toyocamycin than other MM cells with low spliced-XBP1 expression, and non-MM cell lines showed little reduction in cellular viability. MM cell lines expressing high spliced-XBP1 showed robust dose-dependent apoptosis after exposure to various concentrations of toyocamycin for 24 hours, as assessed by the number of Annexin V-positive cells. Toyocamycin also induces marked apoptosis on two bortezomib (BTZ)-resistant MM cells at nM concentration. It also inhibited constitutive activation of XBP1 expression in primary MM cells derived from patients, showing dose-dependent reduced viability without any cytotoxicity to PBMCs from healthy donors. Toyocamycin also showed synergistic effects with bortezomib, and induced apoptosis of primary MM cells from patients including bortezomib-resistant cases at nano-molar levels in a dose-dependent manner. It also inhibited growth of xenografts in an in vivo model of human MM, and showed enhanced growth inhibition when combined with bortezomib. Taken together, we found that adenosine analog toyocamycin has a potent IRE1α-XBP1 inhibitory effect on MM cells with excessive ER-stress. It triggers dose-dependent apoptosis in MM cells. These results suggest toyocamycin can be a lead compound for developing novel anti-MM therapy, and also provide a preclinical rationale for conducting clinical trials using toyocamycin or other adenosine analog alone or in combination with BTZ for treating MM. Disclosures: No relevant conflicts of interest to declare.

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