Alkannin Attenuates Amyloid ß Aggregation and Alzheimer's Disease Pathology.

Alzheimer's disease (AD) is a neurodegenerative disease that is accompanied by memory decline and cognitive dysfunction. Aggregated amyloid ß formation and accumulation may be one of the underlying mechanisms of the pathophysiology of AD. Therefore, compounds that can inhibit amyloid ß aggregation may be useful for treatment. Based on this hypothesis, we screened plant compounds used in Kampo medicine for chemical chaperone activity and identified that alkannin had this property. Further analysis indicated that alkannin could inhibit amyloid ß aggregation. Importantly, we also found that alkannin inhibited amyloid ß aggregation after aggregates had already formed. Through the analysis of circular dichroism spectra, alkannin was found to inhibit ß-sheet structure formation, which is an aggregation-prone toxic structure. Furthermore, alkannin attenuated amyloid ß-induced neuronal cell death in PC12 cells, ameliorated amyloid ß aggregation in the AD model of Caenorhabditis elegans (C. elegans), and inhibited chemotaxis observed in AD C. elegans, suggesting that alkannin could potentially inhibit neurodegeneration in vivo. Overall, these results suggest that alkannin may have novel pharmacological properties for inhibiting amyloid ß aggregation and neuronal cell death in AD. SIGNIFICANCE STATEMENT: Aggregated amyloid ß formation and accumulation is one of the underlying mechanisms of the pathophysiology of Alzheimer's disease. We found that alkannin had chemical chaperone activity, which can inhibit ß-sheet structure formation of amyloid ß and its aggregation, neuronal cell death, and Alzheimer's disease phenotype in C. elegans. Overall, alkannin may have novel pharmacological properties for inhibiting amyloid ß aggregation and neuronal cell death in Alzheimer's disease.

Long-term treatment of Japanese cedar pollinosis with Japanese cedar pollen SLIT drops and persistence of treatment effect: A post-marketing clinical trial.

BACKGROUND: There have been no reports of treatment effect persistence after long-term sublingual immunotherapy (SLIT) in patients with Japanese cedar (JC) pollinosis. Therefore, we conducted a post-marketing clinical trial to investigate the efficacy, safety, and effect persistence of JC pollen SLIT drops after approximately 3 years of treatment. METHODS: This was an open-label trial of 233 patients with JC pollinosis who were treated with JC pollen SLIT drops for approximately 3 years (2015-2017) and followed-up for an additional 2 years (2018-2019). Efficacy and effect persistence were evaluated using nasal and ocular symptom scores, daily use of rescue medication, and Japanese Rhinoconjunctivitis Quality of Life Questionnaire scores recorded during the JC pollen dispersal season of each year. Safety was evaluated by monitoring adverse events and adverse drug reactions. RESULTS: The mean combined total nasal symptom and medication score (range 0-18) during the peak symptom periods of 2015 through 2019 were 5.47 ± 3.38, 4.52 ± 3.13, 3.58 ± 2.63, 5.28 ± 4.01, and 6.83 ± 4.65, respectively. The percentage of patients who used no rescue medications during the same periods was 64.8%, 75.2%, 80.3%, 63.7%, and 50.3%, respectively. A total of 138 adverse drug reaction incidents were recorded in 73 of the 233 patients (31.3%), of which 134 incidents (97.1%) were mild in severity. CONCLUSIONS: JC pollen SLIT drops demonstrated treatment duration-dependent efficacy with effects that persisted for 2 years after cessation of treatment. The drug had a favorable safety profile over the 5-year study period.

[The effect of zinc agent in 219 patients with zinc deficiency-inductive/ idiopathic taste disorder: a placebo controlled randomized study].

Diagnosis and treatment of taste disorders are challenging because the disorder can only be determined by the awareness of the patient. Hence, these disorders still require comprehensive evidence. We conducted a randomized, placebo-controlled double-blind study to investigate the effect of polaprezinc, a zinc-containing agent, in 219 patients with either zinc deficiency-inductive or an idiopathic taste, disorder. As a result, the zinc-treated arm experienced a statistically significant improvement against the placebo-treated arm in the perceptible threshold scores of the filter-paper disk method 8 weeks after the administration of the investigational drug. Moreover, the effect lasted for 4 weeks after discontinuation of the drug. However, the effective ratios based on the initial criteria were 55.6% in the treatment group and 43.2% in the placebo, where no statistical significance was recorded. Sex and degree of depression could be two of the potential factors to explain this discrepancy. Furthermore, the effect was not significant among male patients and patients with a high depression score based on the Self-rating Depression Scale (SDS) test. These results indicate that determining the symptom among such patients remains undisclosed. Whereas, in approximately 77%, or 168 patients with "normal" SDS scores and with completely impaired taste qualities, the ratio of effective cases reached 60.9% in the zinc-treated group, the ratio of the placebo-treated group reached 39.5%, resulting in a statistical significance. This may be partly because of a problem in the adaption of male subjects to the gustatory analyses, especially to the identification of saltiness and sourness. Care must also be taken regarding the depressive state of patients when diagnosing and treating taste disorders. Taste disorders caused by depression may not be cured by zinc supplementation due in part to the fact that the symptom is based on a mental issue, and due in part to the conservative responding bias generated by the depression itself, which may inhibit accurate and precise diagnosis of the disorder. In conclusion, administration of a zinc agent is effective for patients with taste disorders, provided selection of appropriate patients is performed, and that proper examination and evaluation are conducted. The present study also indicated that examining depressiveness based on the SDS scores and investigating disturbance of each taste quality using the filter-paper disk method are recommended for the diagnosis and determination of the treatment effect of a taste disorder.

Antioxidative activity and ameliorative effects of memory impairment of sulfur-containing compounds in Allium species.

The antioxidative activity and ameliorative effects on memory impairment by sulfur-containing compounds which occur in Allium vegetables such as onion and garlic were investigated. The antioxidative activities of S-alk(en)yl-L-cysteines and their sulfoxides, volatile alk(en)yl disulfides and trisulfides, and vinyldithiins were examined by using human low-density lipoprotein. It was elucidated that the alk(en)yl substituents and the number of sulfur atoms in the compounds were important for the antioxidative activities. To demonstrate the ameliorative effects on memory impairment, onion extract and synthesized di-n-propyl trisulfide were administered to senescence-accelerated mouse P8. The behavioral experiments showed that onion extract and di-n-propyl trisulfide had highly ameliorative effect of memory impairment. Furthermore, it was found that the hippocampus lipid hydroperoxide in senescence-accelerated mouse P8 was decreased by the administration of di-n-propyl trisulfide. These results suggest that di-n-propyl trisulfide contained in onion ameliorates memory impairment in SAMP8 mouse by its antioxidant effect.

Effect of subdiaphragmatic vagotomy on bacterial DNA-induced IL-1beta expression in the mouse hypothalamus.

We investigated whether bacterial DNA (CpG-DNA)-induced IL-1beta expression in the mouse hypothalamus is mediated via afferent vagus nerve. Subdiaphragmatic vagotomy did not modify the CpG-DNA (i.p.)-induced IL-1beta expression in the hypothalamus, indicating that CpG-DNA-induced IL-1beta expression is independent of the afferent vagus nerve originating from the subdiaphragmatic organs. On the other hand, we observed the Toll-like receptor 9 mRNA expression in the hypothalamus, suggesting that circulating CpG-DNA acts directly in the brain.

Induction of murine HRD1 in experimental cerebral ischemia.

Hrd1p in yeast plays an important role in endoplasmic reticulum-associated degradation (ERAD). In the present study, we used an in vivo model of hypoxia-ischemia in mice to study the expression of murine HRD1. Hypoxia-ischemia induced a significant increase in mRNA levels of genes including GRP78, CHOP and MyD116, the expression of which are specifically activated under conditions associated with ER dysfunction. The level of mHRD1 mRNA was significantly increased after ischemia. Interestingly, induction of mHRD1 was elevated at a later time point (12-48 h) in the ischemic cortex, whereas it increased at an earlier time point (3-12 h) in the injured striatum. We also examined the changes of mHRD1 mRNA expression in neuroblastoma Neuro2a and primary glial cells exposed to hypoxia/reoxygenation. The expression of mHRD1 mRNA was remarkably up-regulated in glial cells subjected to 24 h hypoxia, whereas no significant changes were observed in Neuro2a cells under hypoxia/reoxygenation. In addition, the levels of mHRD1 mRNA were markedly elevated in glial cells exposed to treatment with tunicamycin (Tm, an ER stress inducer). These findings suggest that hypoxia-ischemia triggers ER dysfunction and mHRD1 may play a role in ischemia-induced ER dysfunction.

Inhibition of leptin-induced IL-1beta expression by glucocorticoids in the brain.

Leptin is an important circulating signal for the regulation of food intake and body weight. Glucocorticoids were suggested to play a physiological role in the feedback inhibition of immune/inflammatory responses. In the present study, we examined whether these neuroendocrine effects of glucocorticoids are linked to changes in the leptin-induced expression of IL-1beta and STAT3 activation in the brain. Intravenous injection of leptin induced IL-1beta expression in the hypothalamus. Pretreatment with dexamethasone dose dependently inhibited leptin-induced IL-1beta expression in the hypothalamus. Moreover, dexamethasone inhibited leptin-induced IL-1beta expression in the primary cultured glial cells. In contrast, pretreatment with dexamethasone did not inhibit leptin-induced STAT3 phosphorylation in the hypothalamus. These effects of dexamethasone may not be due to the change in the expression level of the leptin receptor Ob-Ra and Ob-Rb isoforms. Therefore, it is suggested that glucocorticoid negatively regulates leptin-induced IL-1beta expression in the brain.

Brain stem is a direct target for leptin's action in the central nervous system.

Leptin is a circulating molecule for the regulation of food intake and body weight suggested to be mediated in the hypothalamus via Ob-Rb receptor, which activates Janus kinase-signal transducer and activator of transcription (STAT) pathways. Although leptin receptors exist in many regions of the brain, there have been few in vivo functional studies of leptin's target site other than the hypothalamus. We report here that peripherally applied leptin increased STAT3 phosphorylation not only in the hypothalamus but also in the brain stem as assessed by Western blotting. Moreover, administration of leptin induced expression of the suppressor of cytokine signaling 3 mRNA, a negative feedback regulator of leptin signaling, in the brain stem as well as in the hypothalamus. Using immunohistochemistry, we observed phosphorylated STAT3-immunoreactive cells in the arcuate nucleus, ventromedial hypothalamus, lateral hypothalamic area of the hypothalamus, and the nucleus of the tractus solitarius, dorsal motor nucleus of the vagus nerve, lateral parabrachial nucleus, and central gray of the brain stem of leptin-injected mice. These findings represent physiologically functional leptin Ob-Rb receptor in the brain stem as well as in the hypothalamus. It is suggested that circulating leptin may directly act in the brain stem to elicit autonomic and neuroendocrine control of food intake and energy expenditure.

Leptin induces IL-1 receptor antagonist expression in the brain.

The ob gene product, leptin, is known to be an important circulating signal for regulation of food intake and body weight. We report here that peripherally applied leptin increased interleukin-1 receptor antagonist (IL-1ra) transcripts in the hypothalamus. Interestingly, we observed leptin-induced increase in IL-1ra transcripts not only in the hypothalamus but also in other brain regions such as the hippocampus, the cortex, the cerebellum, and the brain stem. Moreover, leptin applied to the db/db mice, which lack functional Ob-Rb receptor, increased IL-1ra mRNA levels in the hyothalamus to a similar extent as in normal mice. These results indicate that the leptin-induced IL-1ra expression in the brain may be mediated through STAT3 independent mechanisms.

Subdiaphragmatic vagotomy fails to inhibit intravenous leptin-induced IL-1beta expression in the hypothalamus.

Leptin is known to be an important circulating signal for regulation of food intake and body weight. Recent evidence has suggested that leptin is involved in infection and inflammation. The afferent vagus nerve is known to be an important component for transmitting peripheral immune signals to the brain, such as interleukin (IL)-1beta expression in the brain, anorexia, and fever responses. In the present study, we investigated whether intravenous leptin-induced IL-1beta expression in the hypothalamus is mediated via afferent vagus nerve. IL-1beta transcripts in the hypothalamus were significantly increased on RT-PCR assessment 1 h after the administration of leptin (1 mg/kg iv) to mice. Subdiaphragmatic vagotomy did not significantly modify intravenous leptin-induced IL-1beta expression in the hypothalamus compared with that in sham-treated mice. These data suggest that circulating leptin directly acts in the brain independently of afferent vagus nerve input originating from the subdiaphragmatic organs.