Prevention of amyloid ß fibril deposition on the synaptic membrane in the precuneus by ganglioside nanocluster-targeting inhibitors.

Alzheimer's disease (AD), a progressive neurodegenerative condition, is one of the most common causes of dementia. Senile plaques, a hallmark of AD, are formed by the accumulation of amyloid ß protein (Aß), which starts to aggregate before the onset of the disease. Gangliosides, sialic acid-containing glycosphingolipids, play a key role in the formation of toxic Aß aggregates. In membrane rafts, ganglioside-bound complexes (GAß) act as nuclei for Aß assembly, suggesting that GAß is a promising target for AD therapy. The formation of GAß-induced Aß assemblies has been evaluated using reconstituted planar lipid membranes composed of synaptosomal plasma membrane (SPM) lipids extracted from human and mouse brains. Although the effects of gangliosides on Aß accumulation in the precuneus have been established, effects on Aß fibrils have not been determined. In this study, Aß42 fibrils on reconstituted membranes composed of SPM lipids prepared from the precuneus cortex of human autopsied brains were evaluated by atomic force microscopy. In particular, Aß42 accumulation, as well as the fibril number and size were higher for membranes with precuneus lipids than for membranes with calcarine cortex lipids. In addition, artificial peptide inhibitors targeting Aß-sensitive ganglioside nanoclusters cleared Aß assemblies on synaptic membranes in the brain, providing a novel therapeutic strategy for AD.

Suicide Screening, Risk Assessment, and Lethal Means Counseling During Zero Suicide Implementation.

OBJECTIVE: The authors measured implementation of Zero Suicide (ZS) clinical practices that support identification of suicide risk and risk mitigation, including screening, risk assessment, and lethal means counseling, across mental health specialty and primary care settings. METHODS: Six health care systems in California, Colorado, Michigan, Oregon, and Washington participated. The sample included members ages ≥13 years from 2010 to 2019 (N=7,820,524 patients). The proportions of patients with suicidal ideation screening, suicide risk assessment, and lethal means counseling were estimated. RESULTS: In 2019, patients were screened for suicidal ideation in 27.1% (range 5.0%-85.0%) of mental health visits and 2.5% (range 0.1%-35.0%) of primary care visits among a racially and ethnically diverse sample (44.9% White, 27.2% Hispanic, 13.4% Asian, and 7.7% Black). More patients screened positive for suicidal ideation in the mental health setting (10.2%) than in the primary care setting (3.8%). Of the patients screening positive for suicidal ideation in the mental health setting, 76.8% received a risk assessment, and 82.4% of those identified as being at high risk received lethal means counseling, compared with 43.2% and 82.4%, respectively, in primary care. CONCLUSIONS: Six health systems that implemented ZS showed a high level of variation in the proportions of patients receiving suicide screening and risk assessment and lethal means counseling. Two opportunities emerged for further study to increase frequency of these practices: expanding screening beyond patients with regular health care visits and implementing risk assessment with lethal means counseling in the primary care setting directly after a positive suicidal ideation screening.

Cyclization of Peptides Enhances the Inhibitory Activity against Ganglioside-Induced Aß Fibril Formation.

Alzheimer's disease is a progressive neurodegenerative disease and is the most common cause of dementia. It has been reported that the assembly of amyloid ß-protein (Aß) on the cell membrane is induced by the interaction of the Aß monomer with gangliosides such as GM1. The ganglioside-bound Aß (GAß) complex acts as a seed to promote the toxic assembly of the Aß fibrils. In a previous study, we found that a GM1 cluster-binding peptide (GCBP) specifically recognizes Aß-sensitive ganglioside nanoclusters and inhibits the assembly of Aß on a GM1-containing lipid membrane. In this study, cysteine-substituted double mutants of GCBP were designed and cyclized by intramolecular disulfide bond formation. Affinity assays indicated that one of the cyclic peptides had a higher affinity to a GM1-containing membrane compared to that of GCBP. Furthermore, surface topography analysis indicated that this peptide recognizes GM1 nanoclusters on the lipid membrane. An evaluation of the inhibitory kinetics indicated that the cyclic peptide could inhibit the formation of Aß fibrils with an IC50 value of 1.2 fM, which is 10,000-fold higher than that of GCBP. The cyclic peptide was also shown to have a clearance effect on Aß fibrils deposited on the lipid membrane and suppressed the formation of toxic Aß assemblies. Our results indicate that the cyclic peptide that binds to the Aß-sensitive ganglioside nanocluster is a potential novel inhibitor of ganglioside-induced Aß assembly.

Evaluation of soft tissue changes around the nose following subspinal Le Fort â osteotomy.

PURPOSE: This study sought to evaluate the effect of subspinal Le Fort Ⅰ osteotomy (SLFⅠO) and alar base chinch suture (ABCS) in preventing postoperative changes of nasal shape following maxillary movement of advancement-impaction (MAI) or advancement-downward (MAD) by analyzing changes of nasal soft tissue on computed tomography (CT) images. METHODS: Forty-three Japanese patients with dentofacial deformity who underwent orthognathic surgery with SLFⅠO and ABCS were retrospectively examined. Maxillary movement and changes to soft tissues around the nose were analyzed using pre- and postoperative CT. RESULTS: Increased nasal width and alar base width, upturning of the nasal tip and flattening of the nose occurred in both groups, with more prominent changes in MAI. MAD showed horizontal maxillary movement strongly correlated with changes in pronasale and subnasale. Preoperative nasal height correlated negatively with changes to nasal height in both groups, and to nasolabial angle and nasal tip angle in MAD. There were no correlations between the tightness of ABCS during operation and postoperative nasal soft tissue changes including nasal width. CONCLUSION: Postoperative changes to nasal shape following SLFⅠO and ABCS need to be considered with advance movements of the maxilla, regardless of vertical maxillary movement. Postoperative pronasale and subnasale may be estimable from the amount of the maxillary advance movement in MAD. Postoperative changes in nasal shape may be more prominent in cases with low nasal height.

Ganglioside Nanocluster-Targeting Peptidyl Inhibitor Prevents Amyloid ß Fibril Formation on the Neuronal Membrane.

Neurotoxicity caused by peptide and protein aggregates is associated with the onset of neurodegenerative diseases. Accumulation of the amyloid ß protein (Aß) induced by neuronal ganglioside-enriched nanodomains (nanoclusters) in the presynaptic neuronal membrane, resulting in toxic oligomeric and fibrous forms, is implicated in the onset of Alzheimer's disease (AD). In the current study, we found that the ganglioside cluster-binding peptide (GCBP), a pentadecapeptide VWRLLAPPFSNRLLP that binds to ganglioside-enriched nanoclusters, inhibits the formation of Aß assemblies with an IC50 of 12 pM and also removes Aß fibrils deposited on the lipid membrane. Thus, in addition to inhibiting Aß assembly formation, GCBP effectively clears toxic Aß assemblies as well, thereby suppressing neuronal cellular damage and death induced by such assemblies. These results indicate that ganglioside cluster-binding molecules may act as novel Aß-targeting drugs with a unique mechanism of action that may be utilized to ameliorate AD.

Heterogeneous Ganglioside-Enriched Nanoclusters with Different Densities in Membrane Rafts Detected by a Peptidyl Molecular Probe.

The specific features of the lateral distribution of gangliosides play key roles in cell-cell communications and the onset of various diseases related to the plasma membrane. We herein demonstrated that an artificial peptide identified from a phage-displayed library is available as a molecular probe for specific ganglioside nanoclustering sites in caveolae/membrane rafts on the cell surface. Atomic force microscopy studies indicated that the peptide specifically binds to the highly enriched monosialoganglioside GM1 nanodomains of reconstituted lipid bilayers composed of GM1, sphingomyelin, cholesterol, and unsaturated phospholipids. The ganglioside-containing area recognized by the peptide on the surface of PC12 cells was part of the area recognized by the cholera toxin B subunit, which has high affinity for GM1. Furthermore, the peptide bound to the cell surface after a treatment with methyl-ß-cyclodextrin (MßCD), which disrupts membrane rafts by removing cholesterol. The present results indicate that there are heterogeneous ganglioside clusters with different ganglioside densities in caveolae/membrane rafts, and the peptidyl probe selectively recognizes the high-density ganglioside nanodomain that resists the MßCD treatment. This peptidyl probe will be useful for obtaining information on the lipid organization of the cell membrane and will help clarify the mechanisms by which the lateral distribution of gangliosides affects biological functions and the onset of diseases.

Root tip-dependent, active riboflavin secretion by Hyoscyamus albus hairy roots under iron deficiency.

Hyoscyamus albus hairy roots with/without an exogenous gene (11 clones) were established by inoculation of Agrobacterium rhizogenes. All clones cultured under iron-deficient condition secreted riboflavin from the root tips into the culture medium and the productivity depended on the number and size of root tips among the clones. A decline of pH was observed before riboflavin production and root development. By studying effects of proton-pump inhibitors, medium acidification with external organic acid, and riboflavin addition upon pH change and riboflavin productivity, we indicate that riboflavin efflux is not directly connected to active pH reduction, and more significantly active riboflavin secretion occurs as a response to an internal requirement in H. albus hairy roots under iron deficiency.