Leuco Ethyl Violet as Self-Activating Prodrug Photocatalyst for In Vivo Amyloid-Selective Oxygenation

Aberrant aggregates of amyloid-β (Aβ) and tau protein (tau), called amyloid, are related to the etiology of Alzheimer disease (AD). Reducing amyloid levels in AD patients is a potentially effective approach to the treatment of AD. The selective degradation of amyloids via small molecule-catalyzed photooxygenation in vivo is a leading approach; however, moderate catalyst activity and the side effects of scalp injury are problematic in prior studies using AD model mice. Here, leuco ethyl violet (LEV) is identified as a highly active, amyloid-selective, and blood-brain barrier (BBB)-permeable photooxygenation catalyst that circumvents all of these problems. LEV is a redox-sensitive, self-activating prodrug catalyst; self-oxidation of LEV through a hydrogen atom transfer process under photoirradiation produces catalytically active ethyl violet (EV) in the presence of amyloid. LEV effectively oxygenates human Aβ and tau, suggesting the feasibility for applications in humans. Furthermore, a concept of using a hydrogen atom as a caging group of a reactive catalyst functional in vivo is postulated. The minimal size of the hydrogen caging group is especially useful for catalyst delivery to the brain through BBB.

Reduced serotonergic transmission alters sensitivity to cost and reward via 5-HT1A and 5-HT1B receptors in monkeys

Serotonin (5-HT) deficiency is a core biological pathology underlying depression and other psychiatric disorders whose key symptoms include decreased motivation. However, the exact role of 5-HT in motivation remains controversial and elusive. Here, we pharmacologically manipulated the 5-HT system in macaque monkeys and quantified the effects on motivation for goal-directed actions in terms of incentives and costs. Reversible inhibition of 5-HT synthesis increased errors and reaction times on goal-directed tasks, indicating reduced motivation. Analysis found incentive-dependent and cost-dependent components of this reduction. To identify the receptor subtypes that mediate cost and incentive, we systemically administered antagonists specific to 4 major 5-HT receptor subtypes: 5-HT1A, 5-HT1B, 5-HT2A, and 5-HT4. Positron emission tomography (PET) visualized the unique distribution of each subtype in limbic brain regions and determined the systemic dosage for antagonists that would achieve approximately 30% occupancy. Only blockade of 5-HT1A decreased motivation through changes in both expected cost and incentive; sensitivity to future workload and time delay to reward increased (cost) and reward value decreased (incentive). Blocking the 5-HT1B receptor also reduced motivation through decreased incentive, although it did not affect expected cost. These results suggest that 5-HT deficiency disrupts 2 processes, the subjective valuation of costs and rewards, via 5-HT1A and 5-HT1B receptors, thus leading to reduced motivation.

Photo-oxygenation of histidine residue inhibits α-synuclein aggregation

Aggregation of α-synuclein (α-syn) into amyloid is the pathological hallmark of several neurodegenerative disorders, including Parkinson disease, dementia with Lewy bodies, and multiple system atrophy. It is widely accepted that α-syn aggregation is associated with neurodegeneration, although the mechanisms are not yet fully understood. Therefore, the inhibition of α-syn aggregation is a potential therapeutic approach against these diseases. This study used the photocatalyst for α-syn photo-oxygenation, which selectively adds oxygen atoms to fibrils. Our findings demonstrate that photo-oxygenation using this photocatalyst successfully inhibits α-syn aggregation, particularly by reducing its seeding ability. Notably, we also discovered that photo-oxygenation of the histidine at the 50th residue in α-syn aggregates is responsible for the inhibitory effect. These findings indicate that photo-oxygenation of the histidine residue in α-syn is a potential therapeutic strategy for synucleinopathies.

Distinct roles of monkey OFC-subcortical pathways in adaptive behavior

To be the most successful, primates must adapt to changing environments and optimize their behavior by making the most beneficial choices. At the core of adaptive behavior is the orbitofrontal cortex (OFC) of the brain, which updates choice value through direct experience or knowledge-based inference. Here, we identify distinct neural circuitry underlying these two separate abilities. We designed two behavioral tasks in which macaque monkeys updated the values of certain items, either by directly experiencing changes in stimulus-reward associations, or by inferring the value of unexperienced items based on the task's rules. Chemogenetic silencing of bilateral OFC combined with mathematical model-fitting analysis revealed that monkey OFC is involved in updating item value based on both experience and inference. In vivo imaging of chemogenetic receptors by positron emission tomography allowed us to map projections from the OFC to the rostromedial caudate nucleus (rmCD) and the medial part of the mediodorsal thalamus (MDm). Chemogenetic silencing of the OFC-rmCD pathway impaired experience-based value updating, while silencing the OFC-MDm pathway impaired inference-based value updating. Our results thus demonstrate a dissociable contribution of distinct OFC projections to different behavioral strategies, and provide new insights into the neural basis of value-based adaptive decision-making in primates.

Multimodal Imaging for Validation and Optimization of Ion Channel-Based Chemogenetics in Nonhuman Primates

Chemogenetic tools provide an opportunity to manipulate neuronal activity and behavior selectively and repeatedly in nonhuman primates (NHPs) with minimal invasiveness. Designer Receptors Exclusively Activated by Designer Drugs (DREADDs) are one example that is based on mutated muscarinic acetylcholine receptors. Another channel-based chemogenetic system available for neuronal modulation in NHPs uses pharmacologically selective actuator modules (PSAMs), which are selectively activated by pharmacologically selective effector molecules (PSEMs). To facilitate the use of the PSAM/PSEM system, the selection and dosage of PSEMs should be validated and optimized for NHPs. To this end, we used a multimodal imaging approach. We virally expressed excitatory PSAM (PSAM4-5HT3) in the striatum and the primary motor cortex (M1) of two male macaque monkeys, and visualized its location through positron emission tomography (PET) with the reporter ligand [18F]ASEM. Chemogenetic excitability of neurons triggered by two PSEMs (uPSEM817 and uPSEM792) was evaluated using [18F]fluorodeoxyglucose-PET imaging, with uPSEM817 being more efficient than uPSEM792. Pharmacological magnetic resonance imaging (phMRI) showed that increased brain activity in the PSAM4-expressing region began ∼13 min after uPSEM817 administration and continued for at least 60 min. Our multimodal imaging data provide valuable information regarding the manipulation of neuronal activity using the PSAM/PSEM system in NHPs, facilitating future applications.SIGNIFICANCE STATEMENT Like other chemogenetic tools, the ion channel-based system called pharmacologically selective actuator module/pharmacologically selective effector molecule (PSAM/PSEM) allows remote manipulation of neuronal activity and behavior in living animals. Nevertheless, its application in nonhuman primates (NHPs) is still limited. Here, we used multitracer positron emission tomography (PET) imaging and pharmacological magnetic resonance imaging (phMRI) to visualize an excitatory chemogenetic ion channel (PSAM4-5HT3) and validate its chemometric function in macaque monkeys. Our results provide the optimal agonist, dose, and timing for chemogenetic neuronal manipulation, facilitating the use of the PSAM/PSEM system and expanding the flexibility and reliability of circuit manipulation in NHPs in a variety of situations.

A mosaic adeno-associated virus vector as a versatile tool that exhibits high levels of transgene expression and neuron specificity in primate brain

Recent emphasis has been placed on gene transduction mediated through recombinant adeno-associated virus (AAV) vector to manipulate activity of neurons and their circuitry in the primate brain. In the present study, we created a novel vector of which capsid was composed of capsid proteins derived from both of the AAV serotypes 1 and 2 (AAV1 and AAV2). Following the injection into the frontal cortex of macaque monkeys, this mosaic vector, termed AAV2.1 vector, was found to exhibit the excellence in transgene expression (for AAV1 vector) and neuron specificity (for AAV2 vector) simultaneously. To explore its applicability to chemogenetic manipulation and in vivo calcium imaging, the AAV2.1 vector expressing excitatory DREADDs or GCaMP was injected into the striatum or the visual cortex of macaque monkeys, respectively. Our results have defined that such vectors secure intense and stable expression of the target proteins and yield conspicuous modulation and imaging of neuronal activity.

Quantitative Assays for Catalytic Photo-Oxygenation of Alzheimer Disease-Related Tau Proteins

Catalytic photo-oxygenation of tau amyloid is a potential therapeutic approach to tauopathies, including Alzheimer disease (AD). However, tau is a complex target containing great molecular size and heterogeneous isoforms/proteoforms. Although catalytic photo-oxygenation has been confirmed when using catalyst 1 and recombinant tau pretreated with heparin, its effects on tau from human patients have not yet been clarified. In this study, focusing on the histidine residues being oxygenated, we have constructed two assay systems capable of quantitatively evaluating the catalytic activity when used on human patient tau: (1) fluorescence labeling at oxygenated histidine sites and (2) LC-MS/MS analysis of histidine-containing fragments. Using these assays, we identified 2 as a promising catalyst for oxygenation of human tau. In addition, our results suggest that aggregated tau induced by heparin is different from actual AD patient tau in developing effective photo-oxygenation catalysts.

Stable neural population dynamics in the regression subspace for continuous and categorical task parameters in monkeys

Neural population dynamics provide a key computational framework for understanding information processing in the sensory, cognitive, and motor functions of the brain. They systematically depict complex neural population activity, dominated by strong temporal dynamics as trajectory geometry in a low-dimensional neural space. However, neural population dynamics are poorly related to the conventional analytical framework of single-neuron activity, the rate-coding regime that analyzes firing-rate modulations using task parameters. To link the rate-coding and dynamical models, we developed a variant of state-space analysis in the regression subspace, which describes the temporal structures of neural modulations using continuous and categorical task parameters. In macaque monkeys, using two neural population datasets containing either of two standard task parameters, contiguous and categorical, we revealed that neural modulation structures are reliably captured by these task parameters in the regression subspace as trajectory geometry in a lower dimension. Furthermore, we combined the classical optimal-stimulus response analysis (usually used in rate-coding analysis) with the dynamical model and found that the most prominent modulation dynamics in the lower dimension were derived from these optimal responses. Using those analyses, we successfully extracted geometries for both task parameters that formed a straight geometry, suggesting that their functional relevance is characterized as a unidimensional feature in their neural modulation dynamics. Collectively, our approach bridges neural modulation in the rate-coding model and the dynamical system and provides researchers with a significant advantage in exploring the temporal structure of neural modulations for pre-existing datasets.Significant statementOur results differ from earlier studies and suggest that our state-space analysis in the regression subspace provides a mechanistic neural population structure for visual recognition of items when monkeys perceived continuous and categorical task parameters. The neural population dynamics obtained from different brain regions using different behavioral tasks were similar and may share some common underlying information processing in a neural network. Our approach provides a simple framework for incorporating the single-neuron approach into the dynamical model as a procedure for describing neural modulation dynamics in the brain. This analytic extension gives researchers a significant advantage in that all types of pre-existing data for single neuron activity are useful for easily exploring their dynamics in a low-dimensional neural modulation space.

Design improvement of the conversion mechanism from balloon inflation to bending motion for inflatable film actuators

Various soft actuators have been investigated to overcome the drawbacks of conventional solid machines and explore the applications of soft robotics. In particular, and because they are expected to be applicable in minimally invasive medicine because of their safety, soft inflatable microactuators using an actuation conversion mechanism from balloon inflation to bending motion have been proposed for high-output bending motion. These microactuators could be applied to create an operation space by safely moving organs and tissues; however, the conversion efficiency could be further improved. This study aimed to improve conversion efficiency by investigating the design of the conversion mechanism. The contact conditions between the inflated balloon and conversion film were examined to improve the contact area for force transmission, with the contact area dependent on the length of the contact arc between the balloon and force conversion mechanism and on the amount of balloon deformation. In addition, surface contact friction between the balloon and film, which affects actuator performance, was also investigated. The generated force of the improved device is 1.21 N at 80 kPa when it bends 10 mm, which is 2.2 times the generated force of the previous design. This improved soft inflatable microactuator is expected to assist in performing operations in a limited space, such as in endoscopic or laparoscopic operations.

Attenuation of α-synuclein aggregation by catalytic photo-oxygenation

We developed catalyst 11 to promote selective photo-oxygenation of α-synuclein amyloid and attenuate its aggregation. Catalyst 11 effectively oxygenated both small and large aggregates. The oxygenated α-synuclein exhibited lower seeding activity than intact α-synuclein. This study corroborates the feasibility of catalytic photo-oxygenation as an anti-synucleinopathy strategy.

INPP5D modulates TREM2 loss-of-function phenotypes in a β-amyloidosis mouse model

The genetic associations of TREM2 loss-of-function variants with Alzheimer disease (AD) indicate the protective roles of microglia in AD pathogenesis. Functional deficiencies of TREM2 disrupt microglial clustering around amyloid β (Aβ) plaques, impair their transcriptional response to Aβ, and worsen neuritic dystrophy. However, the molecular mechanism underlying these phenotypes remains unclear. In this study, we investigated the pathological role of another AD risk gene, INPP5D, encoding a phosphoinositide PI(3,4,5)P3 phosphatase expressed in microglia. In a Tyrobp-deficient TREM2 loss-of-function mouse model, Inpp5d haplodeficiency restored the association of microglia with Aβ plaques, partially restored plaque compaction, and astrogliosis, and reduced phosphorylated tau+ dystrophic neurites. Mechanistic analyses suggest that TREM2/TYROBP and INPP5D exert opposing effects on PI(3,4,5)P3 signaling pathways as well as on phosphoproteins involved in the actin assembly. Our results suggest that INPP5D acts downstream of TREM2/TYROBP to regulate the microglial barrier against Aβ toxicity, thereby modulates Aβ-dependent pathological conversion of tau.

Soluble form of the APP fragment, sAPPβ, positively regulates tau secretion

Extracellular tau has been highlighted in the pathogenesis of Alzheimer disease (AD), which is the most common neurodegenerative disease. Pathological analyses as well as model animal studies suggest that amyloid-β peptide (Aβ) deposition facilitates the spreading of tau aggregation pathology via extracellular tau. However, the precise mechanism of tau secretion remains unknown. Here, we show that the overexpression of amyloid precursor protein (APP) enhances the secretion of tau phosphorylated at threonine 181 in mouse neuroblastoma Neuro2a cells. Moreover, we found that soluble amyloid precursor protein β (sAPPβ), which is generated by β-site APP cleaving enzyme 1 (BACE1), mediates tau secretion. Our results demonstrate that BACE1-mediated cleavage of APP plays pathological roles in AD pathogenesis by not only Aβ production, but by the spreading of tau aggregation pathology via sAPPβ in AD patients.

[Identification of novel regulators involved in AD pathogenesis using the CRISPR-Cas9 system]

The production of amyloid β peptide (Aβ) is an important process relating to the pathogenesis of Alzheimer disease (AD). It is widely known that the sequential cleavage of amyloid precursor protein (APP) by β- and γ-secretases lead to the production of Aβ. However, the precise regulatory mechanism for Aβ production remains unclear. We have established a CRISPR-Cas9 based screening system to identify the novel regulators of Aβ production. Calcium and integrin-binding protein 1 (CIB1) was identified as a novel potential negative regulator of Aβ production. The knockdown and knockout of Cib1 significantly increased Aβ levels. In addition, immunoprecipitation showed that CIB1 interacts with the γ-secretase complex but did not alter its enzymatic activity. Moreover, Cib1 disruption specifically reduced the cell-surface localization of the γ-secretase complex. Finally, the single-cell RNA-seq analysis in the human brain demonstrated that early-stage AD patients have lower neuronal CIB1 mRNA levels compared to healthy controls. Taken together, we have shown that CIB1 controls the subcellular localization of γ-secretase, resulting in the regulation of Aβ production, suggesting the involvement of CIB1 in the development of AD pathogenesis.

Chemogenetic Disconnection between the Orbitofrontal Cortex and the Rostromedial Caudate Nucleus Disrupts Motivational Control of Goal-Directed Action

The orbitofrontal cortex (OFC) and its major downstream target within the basal ganglia-the rostromedial caudate nucleus (rmCD)-are involved in reward-value processing and goal-directed behavior. However, a causal contribution of the pathway linking these two structures to goal-directed behavior has not been established. Using the chemogenetic technology of designer receptors exclusively activated by designer drugs with a crossed inactivation design, we functionally and reversibly disrupted interactions between the OFC and rmCD in two male macaque monkeys. We injected an adeno-associated virus vector expressing an inhibitory designer receptor, hM4Di, into the OFC and contralateral rmCD, the expression of which was visualized in vivo by positron emission tomography and confirmed by postmortem immunohistochemistry. Functional disconnection of the OFC and rmCD resulted in a significant and reproducible loss of sensitivity to the cued reward value for goal-directed action. This decreased sensitivity was most prominent when monkeys had accumulated a certain amount of reward. These results provide causal evidence that the interaction between the OFC and the rmCD is needed for motivational control of action on the basis of the relative reward value and internal drive. This finding extends the current understanding of the physiological basis of psychiatric disorders in which goal-directed behavior is affected, such as obsessive-compulsive disorder.SIGNIFICANCE STATEMENT In daily life, we routinely adjust the speed and accuracy of our actions on the basis of the value of expected reward. Abnormalities in these kinds of motivational adjustments might be related to behaviors seen in psychiatric disorders such as obsessive-compulsive disorder. In the current study, we show that the connection from the orbitofrontal cortex to the rostromedial caudate nucleus is essential for motivational control of action in monkeys. This finding expands our knowledge about how the primate brain controls motivation and behavior and provides a particular insight into disorders like obsessive-compulsive disorder in which altered connectivity between the orbitofrontal cortex and the striatum has been implicated.

Photo-Oxygenation as a New Therapeutic Strategy for Neurodegenerative Proteinopathies by Enhancing the Clearance of Amyloid Proteins

Alzheimer disease (AD) is associated with the aggregation of two amyloid proteins: tau and amyloid-β (Aβ). The results of immunotherapies have shown that enhancing the clearance and suppressing the aggregation of these two proteins are effective therapeutic strategies for AD. We have developed photocatalysts that attach oxygen atoms to Aβ and tau aggregates via light irradiation. Photo-oxygenation of these amyloid aggregates reduced their neurotoxicity by suppressing their aggregation both in vitro and in vivo. Furthermore, photo-oxygenation enhanced the clearance of Aβ in the brain and microglial cells. Here, we describe the effects of photo-oxygenation on tau and Aβ aggregation, and the potential of photo-oxygenation as a therapeutic strategy for AD, acting via microglial clearance.

Photo-Oxygenation: An Innovative New Therapeutic Approach Against Amyloidoses

Many types of amyloidoses are pathologically characterized by the deposition of amyloid, which is comprised of fibrils formed by abnormally aggregated proteins, in various peripheral tissues and the central nervous system (CNS). Neurodegenerative disorders, such as Alzheimer disease (AD), Parkinson disease (PD), frontotemporal dementia (FTD), and amyotrophic lateral sclerosis (ALS), are well-known CNS amyloidoses that are characterized by amyloid deposition both inside and outside of cells. The amyloidogenic proteins of each disease have distinct primary sequences, and they normally function as soluble proteins. However, these proteins all aggregate and form amyloid with a common intermolecular tertiary structure, namely, a cross-β-sheet structure, finally leading to the onset of each disease. Therefore, inhibition of the aggregation of amyloid proteins or efficient clearance of the already formed amyloids are thought to be promising therapeutic strategies against amyloidoses.

Promotion in the Clearance of Aggregated Aβ In Vivo Using Amyloid Selective Photo-Oxygenation Technology

Alzheimer’s disease (AD) is characterized by the aggregation and deposition of 2 amyloid proteins: amyloid β peptide (Aβ) and tau protein. Immunotherapies using anti-Aβ antibodies to promote the clearance of aggregated Aβ have recently been highlighted as a promising disease-modifying approach against AD. However, immunotherapy has still some problems, such as low efficiency of delivery into the brain and high costs. We have developed the “amyloid selective photo-oxygenation technology” as a comparable to immunotherapy for amyloids. The photo-oxygenation can artificially attach the oxygen atoms to specific amino acids in amyloid proteins using photocatalyst and light irradiation. We revealed that in vivo photo-oxygenation for living AD model mice reduced the aggregated Aβ in the brain. Moreover, we also showed that microglia were responsible for this promoted clearance of photo-oxygenated Aβ from the brain. These results indicated that our photo-oxygenation technology has the potential as a disease-modifying therapy against AD to promote the degradation of amyloids, resulting in being comparable to immunotherapy. Here, we introduce our technology and its effects in vivo that we showed previously in Ozawa et al., Brain, 2021, as well as a further improvement towards non-invasive in vivo photo-oxygenation described in another publication Nagashima et al., Sci. Adv., 2021, as expanded discussion.

Chemogenetic sensory fMRI reveals behaviorally relevant bidirectional changes in primate somatosensory network

Concurrent genetic neuromodulation and functional magnetic resonance imaging (fMRI) in primates has provided a valuable opportunity to assess the modified brain-wide operation in the resting state. However, its application to link the network operation with behavior still remains challenging. Here, we combined chemogenetic silencing of the primary somatosensory cortex (SI) with tactile fMRI and related behaviors in macaques. Focal chemogenetic silencing of functionally identified SI hand region impaired grasping behavior. The same silencing also attenuated hand stimulation-evoked fMRI signal at both the local silencing site and the anatomically and/or functionally connected downstream grasping network, suggesting altered network operation underlying the induced behavioral impairment. Furthermore, the hand region silencing unexpectedly disinhibited foot representation with accompanying behavioral hypersensitization. These results demonstrate that focal chemogenetic silencing with sensory fMRI in macaques unveils bidirectional network changes to generate multifaceted behavioral impairments, thereby opening a pivotal window toward elucidating the causal network operation underpinning higher brain functions in primates.

Time-to-onset of diabetes with everolimus use: analysis of a spontaneous reporting system database

The incidence of hyperglycemia and diabetes induced by everolimus has been shown in previous studies. Our study analyzed diabetes time-to-onset profiles after everolimus use in patients who underwent transplantation and patients with cancer. Using data from April 2007 to December 2018 in the Japanese Adverse Drug Event Report database, the reports with everolimus were classified according to its use as an immunosuppressant or anticancer drug. The median (25%-75%) days of diabetes time-to-onset in patients who underwent transplantation and patients with cancer were 172 (56-315) and 32 (18.5-57), respectively. There were no significant variations among patients with breast cancer, neuroendocrine tumor, and renal cell carcinoma. By conducting a Weibull shape parameter test, the lower limits of the 95% confidence intervals of the shape parameter β values for the indications of the cancer types were >1, indicating the wear out failure type profile, whereas those for transplantation data indicated a random failure type profile. The diabetes time-to-onset profiles after everolimus use differed between usage as an anticancer drug and immunosuppressant and there were no significant variations among the type of cancer. It was suggested that the incidence of diabetes should be monitored for 1-2 months in patients with cancer, whereas continuous monitoring is needed in patients who undergo transplantation.

Chemogenetic activation of nigrostriatal dopamine neurons in freely moving common marmosets

To interrogate particular neuronal pathways in nonhuman primates under natural and stress-free conditions, we applied designer receptors exclusively activated by designer drugs (DREADDs) technology to common marmosets. We injected adeno-associated virus vectors expressing the excitatory DREADD hM3Dq into the unilateral substantia nigra (SN) in four marmosets. Using multi-tracer positron emission tomography imaging, we detected DREADD expression in vivo, which was confirmed in nigrostriatal dopamine neurons by immunohistochemistry, as well as by assessed activation of the SN following agonist administration. The marmosets rotated in a contralateral direction relative to the activated side 30-90 min after consuming food containing the highly potent DREADD agonist deschloroclozapine (DCZ) but not on the following days without DCZ. These results indicate that non-invasive and reversible DREADD manipulation will extend the utility of marmosets as a primate model for linking neuronal activity and natural behavior in various contexts.

Single caudate neurons encode temporally discounted value for formulating motivation for action

The term 'temporal discounting' describes both choice preferences and motivation for delayed rewards. Here we show that neuronal activity in the dorsal part of the primate caudate head (dCDh) signals the temporally discounted value needed to compute the motivation for delayed rewards. Macaque monkeys performed an instrumental task, in which visual cues indicated the forthcoming size and delay duration before reward. Single dCDh neurons represented the temporally discounted value without reflecting changes in the animal's physiological state. Bilateral pharmacological or chemogenetic inactivation of dCDh markedly distorted the normal task performance based on the integration of reward size and delay, but did not affect the task performance for different reward sizes without delay. These results suggest that dCDh is involved in encoding the integrated multi-dimensional information critical for motivation.

GPR120 Signaling Controls Amyloid-β Degrading Activity of Matrix Metalloproteinases

Alzheimer's disease (AD) is characterized by the extensive deposition of amyloid-β peptide (Aβ) in the brain. Brain Aβ level is regulated by a balance between Aβ production and clearance. The clearance rate of Aβ is decreased in the brains of sporadic AD patients, indicating that the dysregulation of Aβ clearance mechanisms affects the pathologic process of AD. Astrocytes are among the most abundant cells in the brain and are implicated in the clearance of brain Aβ via their regulation of the blood-brain barrier, glymphatic system, and proteolytic degradation. The cellular morphology and activity of astrocytes are modulated by several molecules, including ω3 polyunsaturated fatty acids, such as docosahexaenoic acid, which is one of the most abundant lipids in the brain, via the G protein-coupled receptor GPR120/FFAR4. In this study, we analyzed the role of GPR120 signaling in the Aβ-degrading activity of astrocytes. Treatment with the selective antagonist upregulated the matrix metalloproteinase (MMP) inhibitor-sensitive Aβ-degrading activity in primary astrocytes. Moreover, the inhibition of GPR120 signaling increased the levels of Mmp2 and Mmp14 mRNAs, and decreased the expression levels of tissue inhibitor of metalloproteinases 3 (Timp3) and Timp4, suggesting that GPR120 negatively regulates the astrocyte-derived MMP network. Finally, the intracerebral injection of GPR120-specific antagonist substantially decreased the levels of TBS-soluble Aβ in male AD model mice, and this effect was canceled by the coinjection of an MMP inhibitor. These data indicate that astrocytic GPR120 signaling negatively regulates the Aβ-degrading activity of MMPs.SIGNIFICANCE STATEMENT The level of amyloid β (Aβ) in the brain is a crucial determinant of the development of Alzheimer's disease. Here we found that astrocytes, which are the most abundant cell type in the CNS, harbor degrading activity against Aβ, which is regulated by GPR120 signaling. GPR120 is involved in the inflammatory response and obesity in peripheral organs. However, the pathophysiological role of GPR120 in Alzheimer's disease remains unknown. We found that selective inhibition of GPR120 signaling in astrocytes increased the Aβ-degrading activity of matrix metalloproteases. Our results suggest that GPR120 in astrocytes is a novel therapeutic target for the development of anti-Aβ therapeutics.

D1- and D2-like receptors differentially mediate the effects of dopaminergic transmission on cost-benefit evaluation and motivation in monkeys

It has been widely accepted that dopamine (DA) plays a major role in motivation, yet the specific contribution of DA signaling at D₁-like receptor (D₁R) and D₂-like receptor (D₂R) to cost–benefit trade-off remains unclear. Here, by combining pharmacological manipulation of DA receptors (DARs) and positron emission tomography (PET) imaging, we assessed the relationship between the degree of D₁R/D₂R blockade and changes in benefit- and cost-based motivation for goal-directed behavior of macaque monkeys. We found that the degree of blockade of either D₁R or D₂R was associated with a reduction of the positive impact of reward amount and increasing delay discounting. Workload discounting was selectively increased by D₂R antagonism. In addition, blocking both D₁R and D₂R had a synergistic effect on delay discounting but an antagonist effect on workload discounting. These results provide fundamental insight into the distinct mechanisms of DA action in the regulation of the benefit- and cost-based motivation, which have important implications for motivational alterations in both neurological and psychiatric disorders.

Using quantitatively controlled pharmacological manipulations, this study teases apart the role of D1- and D2-like dopamine receptors in motivation and goal-directed behavior in monkeys, revealing complementary roles of two dopamine receptor subtypes in the computation of the cost/benefit trade-off to guide action.

Chemogenetic dissection of the primate prefronto-subcortical pathways for working memory and decision-making

The primate prefrontal cortex (PFC) is situated at the core of higher brain functions via neural circuits such as those linking the caudate nucleus and mediodorsal thalamus. However, the distinctive roles of these prefronto-subcortical pathways remain elusive. Combining in vivo neuronal projection mapping with chemogenetic synaptic silencing, we reversibly dissected key pathways from dorsolateral part of the PFC (dlPFC) to the dorsal caudate (dCD) and lateral mediodorsal thalamus (MDl) individually in single monkeys. We found that silencing the bilateral dlPFC-MDl projections, but not the dlPFC-dCD projections, impaired performance in a spatial working memory task. Conversely, silencing the unilateral dlPFC-dCD projection, but not the unilateral dlPFC-MDl projection, altered preference in a decision-making task. These results revealed dissociable roles of the prefronto-subcortical pathways in working memory and decision-making, representing the technical advantage of imaging-guided pathway-selective chemogenetic manipulation for dissecting neural circuits underlying cognitive functions in primates.

Prognostic Role of Tumor-Infiltrating Lymphocytes and Tumor Budding in Early Oral Tongue Carcinoma

Objectives/Hypothesis

Occult lymph metastasis is an important prognosticator for the treatment of early oral tongue squamous cell carcinoma (SCC). The objective of this study was to evaluate the prognostic significance of tumor‐infiltrating lymphocytes (TILs) in early oral tongue SCC. The combination of the TIL subtype and intermediate‐ or high‐grade budding scores was investigated as a prognostic marker for occult neck metastases.

Study Design

Retrospective study.

Methods

Specimens from 62 patients with early oral tongue SCC treated with only primary surgery were analyzed by immunohistochemistry for CD4+, CD8+, FoxP3+, and CD45RO+ T cells and CD163+ macrophages. The highest number of each TIL subtype was counted in two areas of parenchyma and stroma in the tumor (Tumor) and peripheral stroma of the invasion margin.

Results

Based on multivariate analysis, a high density of Tumor CD163+ macrophages served as the poorest prognostic factor for regional control (RC) and disease‐free survival (DFS). Patients with both a high density of Tumor CD163+ macrophages and an intermediate‐ or a high‐grade budding score had a poor prognosis for RC according to the log‐rank test.

Conclusions

In summary, each TIL subtype may use different mechanisms during early and advanced stages of oral tongue SCC. A high density of Tumor CD163+ macrophages was determined to be a risk factor for RC and DFS as well as an additional stratification factor for RC in patients with intermediate‐ or high‐grade budding scores. Therefore, identifying TIL subtypes in daily clinical practice can help determine a more successful and individualized therapeutic approach for early oral tongue SCC.

Level of Evidence

Step 4 (Level 4) Laryngoscope, 131:2512–2518, 2021

Photo-oxygenation by a biocompatible catalyst reduces amyloid-β levels in Alzheimer's disease mice

Amyloid formation and the deposition of the amyloid-β peptide are hallmarks of Alzheimer's disease pathogenesis. Immunotherapies using anti-amyloid-β antibodies have been highlighted as a promising approach for the prevention and treatment of Alzheimer's disease by enhancing microglial clearance of amyloid-β peptide. However, the efficiency of antibody delivery into the brain is limited, and therefore an alternative strategy to facilitate the clearance of brain amyloid is needed. We previously developed an artificial photo-oxygenation system using a low molecular weight catalytic compound. The photocatalyst specifically attached oxygen atoms to amyloids upon irradiation with light, and successfully reduced the neurotoxicity of aggregated amyloid-β via inhibition of amyloid formation. However, the therapeutic effect and mode of actions of the photo-oxygenation system in vivo remained unclear. In this study, we demonstrate that photo-oxygenation facilitates the clearance of aggregated amyloid-β from the brains of living Alzheimer's disease model mice, and enhances the microglial degradation of amyloid-β peptide. These results suggest that photo-oxygenation may represent a novel anti-amyloid-β strategy in Alzheimer's disease, which is compatible with immunotherapy.

Macaques Exhibit Implicit Gaze Bias Anticipating Others' False-Belief-Driven Actions via Medial Prefrontal Cortex

The ability to infer others' mental states is essential to social interactions. This ability, critically evaluated by testing whether one attributes false beliefs (FBs) to others, has been considered to be uniquely hominid and to accompany the activation of a distributed brain network. We challenge the taxon specificity of this ability and identify the causal brain locus by introducing an anticipatory-looking FB paradigm combined with chemogenetic neuronal manipulation in macaque monkeys. We find spontaneous gaze bias of macaques implicitly anticipating others' FB-driven actions. Silencing of the medial prefrontal neuronal activity with inhibitory designer receptor exclusively activated by designer drugs (DREADDs) specifically eliminates the implicit gaze bias while leaving the animals' visually guided and memory-guided tracking abilities intact. Thus, neuronal activity in the medial prefrontal cortex could have a causal role in FB-attribution-like behaviors in the primate lineage, emphasizing the importance of probing the neuronal mechanisms underlying theory of mind with relevant macaque animal models.

Catalytic photooxygenation degrades brain Aβ in vivo

Protein degradation induced by small molecules by recruiting endogenous protein degradation systems, such as ubiquitin-proteasome systems, to disease-related proteins is an emerging concept to inhibit the function of undruggable proteins. Protein targets without reliable ligands and/or existing outside the cells where ubiquitin-proteasome systems do not exist, however, are beyond the scope of currently available protein degradation strategies. Here, we disclose photooxygenation catalyst 7 that permeates the blood-brain barrier and selectively and directly degrades an extracellular Alzheimer's disease-related undruggable protein, amyloid-β protein (Aβ). Key was the identification of a compact but orange color visible light-activatable chemical catalyst whose activity can be switched on/off according to its molecular mobility, thereby ensuring high selectivity for aggregated Aβ. Chemical catalyst-promoted protein degradation can be applied universally for attenuating extracellular amyloids and various pathogenic proteins and is thus a new entry to induced protein degradation strategies.

Intravenous transplantation of human muse cells improves blood perfusion in a mouse model of limb ischemia

Introduction

Critical limb ischemia (CLI) is the end-stage of peripheral artery disease caused by atherosclerosis and inflammation. Despite advances in treatment of CLI, substantial number of patients with CLI suffer from severe pain, ulceration, and gangrene. Although the advent of stem cell-based therapy has opened a new avenue for the treatment of various diseases, accumulating evidence suggests current cell-based therapies are safe, but their efficacy is modest in CLI patients. Multilineage-differentiating stress enduring (Muse) cells were first reported by one of the authors and colleagues as endogenous pluripotent-like stem cells residing in the bone marrow, peripheral blood and connective tissue of many organs. Previous studies have demonstrated that systemic administration of exogenous Muse cells improves functional recovery after ischemic organ injury such as myocardial infarction. However, their therapeutic potential in CLI remains unclear.

Objective

The goal of this study is to elucidate the efficacy and safety of exogenous Muse cell transplantation with animal models of CLI.

Methods

Muse cells were isolated from human bone marrow-derived mesenchymal stem cells (MSCs) by fluorescence-activated cell sorting with anti-SSEA-3 antibody. To establish an animal model of CLI, 12–14-week-old male BALB/c mice were anesthetized and subjected to left femoral artery and vein resection. At 24 hours after establishment of hindlimb ischemia, mice were randomly divided into 5 groups and treated as follows: Group 1, intravenous injection of PBS as control group; group 2, intravenous injection of 3 × 104 SSEA3-negative MSCs (non-Muse MSCs); group 3, intravenous injection of 3 × 104 Muse cells; group 4, intramuscular injection of 3 × 104 Muse cells into ischemic limb; group 5, intramuscular injection of 2 × 105 mouse bone marrow-derived mononuclear cells (BM-MNCs) into ischemic limb (n=5 for each group). Hindlimb blood flow was evaluated by laser Doppler flowmetry for 14 days and expressed as the ratio of ischemic to non-ischemic hindlimb.

Results

We found that intramuscular injection of xenogeneic Muse cells without immunosuppression significantly improved the blood flow in the ischemic hindlimb compared to control at day 7 and 14 (0.67 vs. 0.52, p=0.0002 and 0.74 vs. 0.53, p<0.0001, respectively) similar to intramuscular injection of allogenic BM-MNCs. In addition, we also found that intravenous injection of xenogeneic Muse cells without immunosuppression significantly improved the blood flow in the ischemic hindlimb compared to control at day 7 and 14 (0.72, p<0.0001 and 0.67, p=0.004, respectively). In contrast, intravenous injection of xenogeneic non-Muse MSCs did not improve blood flow in the ischemic hindlimb.

Conclusion

Our result suggests that Muse cell-based regenerative therapy could be a novel, less invasive, cost-effective, and subsequently more effective treatment for CLI patients.

Funding Acknowledgement

Type of funding source: Public grant(s) – National budget only. Main funding source(s): Grant-in-Aid for Scientific Research (KAKENHI)

The correlations between anti-factor Xa activity values and PT/APTT at peak and trough times in patients with venous thromboembolism using high dose of apixaban

Background

The high dose (20mg/day) of apixaban is used for the initial treatment of venous thromboembolism for the first week. Although patients taking direct oral anticoagulants do not require routine coagulation monitoring, the correlations between anti-factor Xa activity (AXA) and routine coagulation markers such as prothrombin time (PT) and activated partial thromboplastin time (APTT) at peak and trough times especially when using high dose of apixaban have not been reported so far.

Purpose

The purpose is to assess the correlations between AXA values and PT/APTT at peak and trough times in patients with venous thromboembolism using high dose of Apixaban.

Methods

Twenty-six patients (10 male; 71±15 years) with proximal venous thromboembolism or pulmonary embolism using high dose (20mg/day) of apixaban were enrolled. We measured AXA, using chromogenic assay with the HemosIL Liquid Heparin kit, PT and APTT at peak and trough times. The peak time was defined as 3 hours after the intake of apixaban, and the trough time was defined as that immediately before the intake of apixaban.

Results

A significant and strong positive correlation was observed between AXA and PT at both peak and trough times (R=0.795, p<0.01 and R=0.766, p<0.01, respectively). A significant and moderate positive correlation was observed between AXA and APTT at trough time (R=0.527, p<0.01), but no correlation was observed between AXA and APTT at peak time (R=0.366, p=0.07).

Conclusion

Our findings reveal the relationship between AXA and PT at peak and trough times has a significant strong correlation. These results suggest measuring of PT may be alternative and effective way of monitoring of AXA values when using high dose of apixaban.

Figure 1

Funding Acknowledgement

Type of funding source: None

The distribution of anti-factor Xa activity value, PT and APTT at peak and trough times in patients with direct anti-factor Xa inhibitors

Background

Although patients taking direct oral anticoagulants (DOACs) do not require routine coagulation monitoring, the distribution of anti-factor Xa activity (AXA) values, prothrombin time (PT), PT-international normalized ratio (INR) and activated partial thromboplastin time (APTT) in patients on apixaban, edoxaban and rivaroxaban therapy is still not clear.

Purpose

The aim is to set the standard values of AXA values, PT, PT-INR and APTT in patients using DOACs.

Methods

We measured AXA, using chromogenic assay with the HemosIL Liquid Heparin kit, PT, PT-INR and APTT at trough and peak times in 224 patients with non-valvular atrial fibrillation and venous thromboembolism, of whom 90 received apixaban, 100 received edoxaban and 34 received rivaroxaban. The peak time was defined as 3 hours after the intake of apixaban or rivaroxaban, and 2 hours after the intake of edoxaban. The trough time was defined as that immediately before the intake. The AXA values, PT, PT-INR and APTT were measured at least 72 hours after the start of treatment. The dosage of DOACs is defined according to the prescribing information in Japan.

Results

(The order of results below is apixaban, edoxaban and rivaroxaban, respectively.) The average AXA values were 2.29, 0.23 and 0.39 (IU/mL) at trough time, and 3.04, 1.01 and 1.70 (IU/mL) at peak time. The average PT values were 17.9, 12.9 and 13.1 (s) at trough time, and 19.7, 15.5 and 17.5 (s) at peak time. The average PT-INR values were 1.49, 1.07 and 1.08 at trough time, and 1.65, 1.29 and 1.45 at peak time. The average APPT values were 34.5, 31.3 and 32.0 (s) at trough time, and 39.5, 35.9 and 39.8 (s) at peak time.

Conclusion

Our findings reveal the standard values of AXA, PT, PT-INR and APTT in patients using apixaban, edoxaban and rivaroxaban in each dosage. The DOACs should be changed if the measured value is out of those standard values in 90% confidence interval.

Funding Acknowledgement

Type of funding source: None

EphA4 regulates Aβ production via BACE1 expression in neurons

Several lines of evidence suggest that the aggregation and deposition of amyloid-β peptide (Aβ) initiate the pathology of Alzheimer's disease (AD). Recently, a genome-wide association study demonstrated that a single-nucleotide polymorphism proximal to the EPHA4 gene, which encodes a receptor tyrosine kinase, is associated with AD risk. However, the molecular mechanism of EphA4 in the pathogenesis of AD, particularly in Aβ production, remains unknown. Here, we performed several pharmacological and biological experiments both in vitro and in vivo and demonstrated that EphA4 is responsible for the regulation of Aβ production. Pharmacological inhibition of EphA4 signaling and knockdown of Epha4 led to increased Aβ levels accompanied by increased expression of β-site APP cleaving enzyme 1 (BACE1), which is an enzyme responsible for Aβ production. Moreover, EPHA4 overexpression and activation of EphA4 signaling via ephrin ligands decreased Aβ levels. In particular, the sterile-alpha motif domain of EphA4 was necessary for the regulation of Aβ production. Finally, EPHA4 mRNA levels were significantly reduced in the brains of AD patients, and negatively correlated with BACE1 mRNA levels. Our results indicate a novel mechanism of Aβ regulation by EphA4, which is involved in AD pathogenesis.

Psoriasis associated with ACE inhibitors: an analysis of the FAERS database

Many case reports have been published concerning the development or exacerbation of psoriasis after administration of angiotensin-converting enzyme (ACE) inhibitors. The aim of the present study was to investigate the association between psoriasis and ACE inhibitors using the US Food and Drug Administration Adverse Event Reporting System (FAERS) data. After excluding patients with psoriasis-related primary diseases, the association of psoriasis with 14 ACE inhibitors was examined using disproportional analyses reporting odds ratio (ROR) and information component (IC). Signals were detected for all 14 ACE inhibitors combined (ROR: 1.25, 95% confidence interval [CI]: 1.14-1.37; IC: 0.31, 95% CI: 0.17-0.44) and individually for lisinopril (ROR: 1.20, 95% CI: 1.05-1.37; IC: 0.25, 95% CI: 0.06-0.45), perindopril (ROR: 1.86, 95% CI: 1.38-2.52; IC: 0.86, 95% CI: 0.43-1.30), and ramipril (ROR: 1.63, 95% CI: 1.36-1.96; IC: 0.69, 95% CI: 0.42-0.96). ACE inhibitors are widely used in patients with hypertension, heart failure, and diabetes mellitus, which are considered comorbidities of psoriasis. Our results suggest that the involvement of ACE inhibitors should be considered in patients on ACE inhibitor therapy who have developed (or show exacerbated) psoriasis.

Deschloroclozapine, a potent and selective chemogenetic actuator enables rapid neuronal and behavioral modulations in mice and monkeys

The chemogenetic technology designer receptors exclusively activated by designer drugs (DREADDs) afford remotely reversible control of cellular signaling, neuronal activity and behavior. Although the combination of muscarinic-based DREADDs with clozapine-N-oxide (CNO) has been widely used, sluggish kinetics, metabolic liabilities and potential off-target effects of CNO represent areas for improvement. Here, we provide a new high-affinity and selective agonist deschloroclozapine (DCZ) for muscarinic-based DREADDs. Positron emission tomography revealed that DCZ selectively bound to and occupied DREADDs in both mice and monkeys. Systemic delivery of low doses of DCZ (1 or 3 μg per kg) enhanced neuronal activity via hM3Dq within minutes in mice and monkeys. Intramuscular injections of DCZ (100 μg per kg) reversibly induced spatial working memory deficits in monkeys expressing hM4Di in the prefrontal cortex. DCZ represents a potent, selective, metabolically stable and fast-acting DREADD agonist with utility in both mice and nonhuman primates for a variety of applications.

Erratum: Evolution of π^{0} Suppression in Au+Au Collisions from sqrt[s_{NN}]=39 to 200 GeV [Phys. Rev. Lett. 109, 152301 (2012)]

This corrects the article DOI: 10.1103/PhysRevLett.109.152301.

The natural course of the paravertebral muscles after the onset of osteoporotic vertebral fracture

This study revealed the change in the paravertebral muscles in patients with osteoporotic vertebral fracture. Increased pain is likely to be the driver for reduced activity, reduced activities of daily living, and consequent increase in fat infiltration of the paravertebral muscles, assumed to be secondary to reduced activity level or, conversely, partial immobilization.

INTRODUCTION

To reveal the time courses and impact of the paravertebral muscles (PVMs) on the healing process of osteoporotic vertebral fractures and risk factors for PVM decrease.

METHODS

Consecutive patients with symptomatic osteoporotic vertebral fractures were enrolled in 11 hospitals. At enrollment and 3- and 6-month follow-up, PVMs, including the multifidus and erector spinae, were examined using magnetic resonance imaging (MRI). The PVM cross-sectional area (CSA) and fat signal fraction (FSF) were measured at L3. Low back pain (LBP), activities of daily living (ADLs), and risk factors for PVM decrease at the 6-month follow-up were investigated. PVM decrease was defined as > 1 standard deviation decrease of the CSA or > 1 standard deviation increase of the FSF.

RESULTS

Among 153 patients who completed the 6-month follow-up, 117 (92 women, 79%) had MRI of L3 at enrollment and 3- and 6-month follow-up (mean age at enrollment, 78.5 years). The CSA did not change 6 months from onset (p for trend = 0.634), whereas the FSF significantly increased (p for trend = 0.033). PVM decrease was observed in 30 patients (26%). LBP was more severe, and delayed union was more frequent in patients with PVM decrease (p = 0.021 mixed-effect model and p = 0.029 chi-square test, respectively). The risk factors for PVM decrease were ADL decline at the 3-month follow-up (adjusted odds ratio = 5.35, p = 0.026).

CONCLUSION

PVM decrease was significantly related to LBP and delayed union after osteoporotic vertebral fracture onset. ADL decline at the 3-month follow-up was a risk factor for PVM decrease. Therefore, restoring ADLs within 3 months after onset is important.

Left ventricular outflow tract pressure gradient changes after carvedilol-disopyramide cotherapy in a cat with hypertrophic obstructive cardiomyopathy

Disopyramide reduces the left ventricular outflow tract (LVOT) pressure gradient and improves symptoms in humans with hypertrophic obstructive cardiomyopathy (HOCM). However, the efficacy of disopyramide in cats has not been reported. We treated a cat with HOCM with carvedilol and disopyramide cotherapy and monitored the changes in LVOT flow velocity and N-terminal pro B-type natriuretic peptide (NT-proBNP) concentration. A 10-month-old neutered male Norwegian Forest cat was referred with a moderate systolic cardiac murmur. Echocardiography revealed thickening of the left ventricular wall, systolic anterior motion of the mitral valve leaflets, and turbulent aortic flow in the LVOT at systole. The LVOT flow velocity was 5.6 m/s. The plasma NT-proBNP concentration exceeded 1,500 pmol/L. The cat was diagnosed with HOCM and the β-blocker carvedilol was started and gradually increased to 0.30 mg/kg, bid. After 57 days, the LVOT flow velocity (4.8 m/s) and plasma NT-proBNP concentration (870 pmol/L) had decreased but remained elevated. Therefore, disopyramide was added at 5.4 mg/kg po bid and increased to 10.9 mg/kg po bid after 22 days. After 141 days of carvedilol and disopyramide treatment, the systolic anterior motion of the mitral valve leaflets had disappeared and the LVOT flow velocity and plasma NT-proBNP concentration had decreased to 0.7 m/s and 499 pmol/L, respectively. No adverse effect has been observed during the follow-up. Disopyramide might relieve feline LVOT obstruction after only partial response to a beta-blocker. Further large-scale studies are required to investigate the efficacy and safety of disopyramide use in cats with moderate to severe HOCM.

Peptide-based short single β-strand mimics without hydrogen bonding or aggregation

Generation of short peptides with a single β-strand structure in solution is difficult. Herein, we design a new class of single β-strand peptidic mimics that are stable without self-aggregation in protic and non-protic solvents. Introduction of one present β-strand mimic can induce and propagate the β-strand structure for at least a penta-peptide sequence.

Evaluation of syncope association with α1-adrenoceptor blockers in males using the FAERS database: impact of concomitant hypertension

Previous studies have revealed an association between the administration of α₁-adrenoceptor blockers (α1Bs) and episodes of syncope in patients with benign prostatic hyperplasia (BPH). The objective of the present study was to evaluate the association between α1Bs and syncope in BPH patients with hypertension using two different pharmacoepidemiological indices. Using the US Food and Drug Administration Adverse Event Reporting System, we analyzed the whole dataset and subsets for specific indications, including hypertension, diabetes, and dyslipidemia, for males older than 40 years. The drugs of interest were alfuzosin, doxazosin, and terazosin as non-selective α1Bs and silodosin and tamsulosin as selective α1Bs. The reporting odds ratio (ROR) and information component (IC) were used for signal detection. The association between the non-selective α1Bs and syncope was observed for all the items examined. The results obtained using the whole dataset, as well as the diabetes and dyslipidemia subsets, were same for the selective and non-selective α1Bs in terms of the association with syncope, while no association with syncope was observed for both silodosin [ROR: 1.09, 95% confidence interval (CI): 0.61-1.93; IC: 0.10, 95% CI: -0.72-0.92] and tamsulosin (ROR: 1.08, 95% CI: 0.90-1.30; IC: 0.10, 95% CI: -0.17-0.37) in patients with hypertension. The data suggested that α1Bs, even those with receptor subtype selectivity, were associated with syncope. Thus, careful attention should be paid when prescribing α1Bs, especially to patients who do not take medications for hypertension.

Beam Energy and Centrality Dependence of Direct-Photon Emission from Ultrarelativistic Heavy-Ion Collisions

The PHENIX collaboration presents first measurements of low-momentum (0.4<p_{T}<3  GeV/c) direct-photon yields from Au+Au collisions at sqrt[s_{NN}]=39 and 62.4 GeV. For both beam energies the direct-photon yields are substantially enhanced with respect to expectations from prompt processes, similar to the yields observed in Au+Au collisions at sqrt[s_{NN}]=200. Analyzing the photon yield as a function of the experimental observable dN_{ch}/dη reveals that the low-momentum (>1  GeV/c) direct-photon yield dN_{γ}^{dir}/dη is a smooth function of dN_{ch}/dη and can be well described as proportional to (dN_{ch}/dη)^{α} with α≈1.25. This scaling behavior holds for a wide range of beam energies at the Relativistic Heavy Ion Collider and the Large Hadron Collider, for centrality selected samples, as well as for different A+A collision systems. At a given beam energy, the scaling also holds for high p_{T} (>5  GeV/c), but when results from different collision energies are compared, an additional sqrt[s_{NN}]-dependent multiplicative factor is needed to describe the integrated-direct-photon yield.

CD2-associated protein (CD2AP) overexpression accelerates amyloid precursor protein (APP) transfer from early endosomes to the lysosomal degradation pathway

A hallmark of Alzheimer's disease (AD) pathology is the appearance of senile plaques, which are composed of β-amyloid (Aβ) peptides. Aβ is produced by sequential cleavages of amyloid precursor protein (APP) by β- and γ-secretases. These cleavages take place in endosomes during intracellular trafficking of APP through the endocytic and recycling pathways. Genome-wide association studies have identified several risk factors for late-onset AD, one of which is CD2-associated protein (CD2AP), an adaptor molecule that regulates membrane trafficking. Although CD2AP's involvement in APP trafficking has recently been reported, how APP trafficking is regulated remains unclear. We sought to address this question by investigating the effect of CD2AP overexpression or knockdown on the intracellular APP distribution and degradation of APP in cultured COS-7 and HEK293 cells. We found that overexpression of CD2AP increases the localization of APP to Rab7-positive late endosomes, and decreases its localization to Rab5-positive early endosomes. CD2AP overexpression accelerated the onset of APP degradation without affecting its degradation rate. Furthermore, nutrient starvation increased the localization of APP to Rab7-positive late endosomes, and CD2AP overexpression stimulated starvation-induced lysosomal APP degradation. Moreover, the effect of CD2AP on the degradation of APP was confirmed by CD2AP overexpression and knockdown in primary cortical neurons from mice. We conclude that CD2AP accelerates the transfer of APP from early to late endosomes. This transfer in localization stimulates APP degradation by reducing the amount of time before degradation initiation. Taken together, these results may explain why impaired CD2AP function is a risk factor for AD.

Loss of kallikrein-related peptidase 7 exacerbates amyloid pathology in Alzheimer's disease model mice

Deposition of amyloid‐β (Aβ) as senile plaques is one of the pathological hallmarks in the brains of Alzheimer's disease (AD) patients. In addition, glial activation has been found in AD brains, although the precise pathological role of astrocytes remains unclear. Here, we identified kallikrein‐related peptidase 7 (KLK7) as an astrocyte‐derived Aβ degrading enzyme. Expression of KLK7 mRNA was significantly decreased in the brains of AD patients. Ablation of Klk7 exacerbated the thioflavin S‐positive Aβ pathology in AD model mice. The expression of Klk7 was upregulated by Aβ treatment in the primary astrocyte, suggesting that Klk7 is homeostatically modulated by Aβ‐induced responses. Finally, we found that the Food and Drug Administration‐approved anti‐dementia drug memantine can increase the expression of Klk7 and Aβ degradation activity specifically in the astrocytes. These data suggest that KLK7 is an important enzyme in the degradation and clearance of deposited Aβ species by astrocytes involved in the pathogenesis of AD.

Photo-oxygenation inhibits tau amyloid formation

Amyloid-selective catalytic photo-oxygenation of the tau protein is a possible therapeutic strategy for Alzheimer's disease, via the inhibition of tau fibril formation.

Retrograde transport of γ-secretase from endosomes to the trans-Golgi network regulates Aβ42 production

The aberrant metabolism of amyloid-β protein (Aβ) in the human brain has been implicated in the etiology of Alzheimer disease (AD). γ-Secretase is the enzyme that generates various forms of Aβ, such as Aβ40 and Aβ42, the latter being an aggregation-prone toxic peptide that is involved in the pathogenesis of AD. Recently, we found that clathrin-mediated endocytosis of γ-secretase affects the production and deposition of Aβ42 in vivo, suggesting that the membrane trafficking of γ-secretase affects its enzymatic activity. However, the detailed intracellular trafficking pathway of γ-secretase and its contribution to Aβ42 generation remain unclear. Here, we show that Retro-2, which inhibits the retrograde transport, elevated the Aβ42-generating activity both in cultured cells and mice brain. However, the result of in vitro γ-secretase assay using a recombinant substrate suggested that Retro-2 did not elevate the intrinsic Aβ42-production activity of γ-secretase. Immunocytochemistry and cell-surface biotinylation experiments revealed that γ-secretase is recycled via the endosome-to-trans-Golgi network transport. In addition, γ-secretase is retrogradely transported by syntaxin 5/6, known as targets of Retro-2, independent pathway. Conversely, TPT-260, which enhances the trafficking function of retromers, lowered Aβ42 levels and the Aβ42/(Aβ40 + Aβ42) ratio in secreted Aβ from cultured cells. Our results strongly suggest that the endosome-to-trans-Golgi network trafficking of γ-secretase regulates its Aβ42 production activity. Modulation of this trafficking pathway might be a potential target for the development of Aβ42-lowering AD therapeutics.

OPEN PRACTICES

Open Science: This manuscript was awarded with the Open Materials Badge. For more information see: https://cos.io/our-services/open-science-badges/.

Diagnostic accuracy of plasma atrial natriuretic peptide concentrations in cats with and without cardiomyopathies

OBJECTIVES

Plasma atrial natriuretic peptide (ANP) levels have been reported to be elevated in cats with cardiomyopathy. We investigated the diagnostic accuracy of plasma ANP concentration as an indicator of the severity of cardiomyopathies.

ANIMALS

This study included 78 control cats and 83 cats with various types of cardiomyopathy.

METHODS

This was a prospective multicentre study. Control cats were determined to have a normal heart, and diseased cats were diagnosed by echocardiography. Diseased cats were divided into asymptomatic cats without left atrial dilation (LAD), asymptomatic cats with LAD, and cats with heart failure. Plasma C-terminal ANP concentrations were measured using chemiluminescence.

RESULTS

The median plasma ANP concentration in controls was 43.3 (interquartile range, 33.0-56.3) pg/mL. Plasma ANP values were significantly higher in the cardiomyopathic cats with LAD and heart failure, but the values in cats without LAD were comparable to those in control cats. To distinguish cats with cardiomyopathy from controls, a plasma ANP concentration >77.5 pg/mL afforded sensitivity of 66.3% and specificity of 84.6%. Use of plasma ANP concentration >110.9 pg/mL to identify cats with LAD had a sensitivity of 73.6% and specificity of 93.5%. The areas under the receiver-operating characteristic curve were 0.80 and 0.86.

CONCLUSIONS

Plasma ANP concentrations were higher in cats with more advanced cardiomyopathy. Although assaying the ANP concentration alone may not help to diagnose cardiac disease, measuring provides additional information that is useful for assessing the severity of cardiomyopathies.