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Background: The utility of gadobutrol (GAD) which is higher r1 value contrast media for evaluating abdominal solid organ have not been fully evaluated. Objectives:: To compare the contrast enhancement of abdominal organs on dynamic MRI using 0.1 mmol/kg 1.0 M GAD or 0.5 M meglumine gadoterate (MG) in patients with a liver hemangioma. Methods: A phantom study was performed at different concentrations (0.05, 0.1, 0.3, 0.5, 0.7, 0.9, 1.0, 5.0 and 10 mmol/L) of GAD and MG. Sixty-two patients with a liver hemangioma were enrolled. Contrast media was injected at a rate of 2 mL/s followed by 40 mL of saline. Two arterial phases, a portal phase and an equilibrium phase were obtained. One certified radiologist set regions of interest on the abdominal aorta, liver, pancreas, spleen and the liver hemangioma. The relative enhancement ratio (RER) was calculated. Results:: In the phantom study the signal intensity of both contrast media was similar at lower concentrations. However, the signal intensity of MG was higher at concentrations of more than 5.0 mmol/L. In the clinical study the RER of the abdominal viscera during the portal and equilibrium phases was higher with GAD. The hemangioma had a higher equilibrium phase enhancement with GAD. The aortic RER was equivalent during all phases and the liver RER during the 2nd arterial phase was higher with GAD. The arterial phase during GAD imaging might have been measured later than was optimal. Conclusions:: When the same injection protocol was used for an abdominal dynamic MRI, arterial phase imaging was late when GAD was used. The higher T1 relaxation value was significantly higher in the abdominal viscera during the portal and equilibrium phases, while the liver hemangioma also had significantly higher contrast enhancement during the equilibrium phase. Clinical trial registration number: 3186.

The detection and characterization of liver lesions are problematic in patients with bronchial asthma, renal dysfunction, or a history of allergy to gadolinium-based magnetic resonance contrast media or iodine-computed tomography contrast media because these contrast media cannot be used. Hence, the information on the lesion vascularity cannot be obtained. Therefore, this retrospective case-control study evaluated the feasibility of superparamagnetic iron oxide (SPIO) in patients with one or more of these contraindications who underwent SPIO-enhanced magnetic resonance imaging for the assessment of liver lesions.Twenty-six patients with a total of 48 lesions were analyzed. SPIO was used in the case of all patients because each patient had at least one reason not to use iodine contrast or gadolinium-based contrast media. Additionally, all patients were subjected to the perfusion study. A total volume of 1.3 mL of SPIO was injected via the cubital vein at a rate of 3 mL per second, followed by 40 mL saline at the same speed. The scanning of the perfusion study was started 4 s after the beginning of superparamagnetic iron oxide injection and scanning took 50 s. Two radiologists independently evaluated whether the lesion was malignant or benign. Receiver operating characteristic analysis (ROC) was performed to determine the additional benefit of the perfusion study.There were no adverse effects associated with SPIO. The area under the curve (AUC) value without perfusion study for observers 1 and 2 were 0.473 (P=0.794, 95% CI: 0.275-0.672) and 0.602 (P=0.305, 95% CI: 0.407-0.798), respectively, whereas the Az values with perfusion study for observers 1 and 2 were 0.782 (P=0.011, 95% CI: 0.565-0.998) and 0.784 (P=0.004, 95% CI: 0.591-0.977), respectively. Az value became significantly better when the perfusion study has added (P=0.001 and 0.012 by observers 1 and 2).SPIO can be used safely in patients with bronchial asthma, renal dysfunction, or a history of contrast media allergy. Furthermore, the diagnostic accuracy of SPIO was acceptable.

SummaryLoss-of-function variants in SYNAGP1 cause a developmental encephalopathy defined by cognitive impairment, autistic features, and epilepsy. SYNGAP1 splicing leads to expression of distinct functional protein isoforms. Splicing imparts multiple cellular functions of SynGAP proteins through coding of distinct C-terminal motifs. However, it remains unknown how these different splice sequences function in vivo to regulate neuronal function and behavior. Reduced expression of SynGAP-α1/2 C-terminal splice variants in mice caused severe phenotypes, including reduced survival, impaired learning, and reduced seizure latency. In contrast, upregulation of α1/2 expression improved learning and increased seizure latency. Mice expressing α1-specific mutations, which disrupted SynGAP cellular functions without altering protein expression, promoted seizure, disrupted synapse plasticity, and impaired learning. These findings demonstrate that endogenous SynGAP isoforms with α1/2 spliced sequences promote cognitive function and impart seizure protection. Regulation of SynGAP-α expression or function may be a viable therapeutic strategy to broadly improve cognitive function and mitigate seizure.

In response to stimuli, the immediate early gene product Arc can acutely down-regulate synaptic strength by removing AMPA receptors (AMPARs) from synapses and thus regulate synaptic plasticity. How Arc, a scaffold protein, can specifically facilitate synaptic removal of AMPARs is unknown. We found that Arc directly antagonizes with PSD-95 in binding to TARPs, which are the auxiliary subunits of AMPARs. Arc, in a highly concentration-sensitive manner, acutely disperses TARPs from the postsynaptic density (PSD) condensate formed via phase separation. TARPs with the Ser residue in the "P-S-Y"-motif of its tail phosphorylated are completely refractory from being dispersed by Arc, suggesting that Arc cannot displace AMPARs from PSDs in active synapses. Conversely, strengthening the interaction between Arc and TARPs enhances Arc's capacity in weakening synapses. Thus, Arc can specifically and effectively modulate synaptic AMPAR clustering via modulating PSD phase separation. Our study further suggests that activity-dependent, bi-directional modulation of PSD condensate formation/dispersion represents a general regulatory mechanism for synaptic plasticity.

Loss-of-function variants in

Accurate staging and evaluation of therapeutic effects are important in managing plasma-cell neoplasms. Diffusion-weighted imaging with body signal suppression magnetic resonance imaging (DWIBS-MRI) allows for acquisition of whole-body volumetric data without radiation exposure. This study aimed to investigate the usefulness of DWIBS-MRI in plasma-cell neoplasms. We retrospectively analyzed 29 and 8 Japanese patients with multiple myeloma and monoclonal gammopathy of undetermined significance, respectively, who underwent DWIBS-MRI. We conducted a histogram analysis of apparent diffusion coefficient values. The correlations between each histogram parameter and staging, cell maturation, prognosis, and treatment response were evaluated. We found that the apparent diffusion coefficient values in patients with monoclonal gammopathy of undetermined significance were lower than those in patients with multiple myeloma. Pretreatment apparent diffusion coefficient values of immature myeloma were lower than those of mature myeloma. Moreover, these values decreased in proportion to stage progression in Durie-Salmon classification system but showed no significant correlation with other staging systems or prognosis. Patients were stratified as responder, stable, and non-responder based on the International Myeloma Working Group criteria. The magnitude of changes in apparent diffusion coefficients differed significantly between responders and non-responders (0.154 ± 0.386 ×10–3 mm2/s vs. -0.307 ± 0.424 ×10–3 mm2/s, p = 0.003). Although its usefulness has yet to be established, DWIBS-MRI combined with apparent diffusion coefficient measurement allowed for excellent response evaluation in patients with multiple myeloma. Furthermore, apparent diffusion coefficient analysis using DWIBS-MRI may be useful in predicting cell maturation and total tumor volume.

Background: Solitary fibrous tumors (SFTs) are rare and can be misdiagnosed because of their various radiological appearances. Purpose: To clarify the characteristic MRI findings of SFTs by analyzing their radiological-pathological correlation. Material and Methods: Nine consecutive patients with SFT who underwent magnetic resonance imaging (MRI) prior to surgery were analyzed. Eight patients underwent contrast-enhanced MRI, and three underwent dynamic MRI. Radiological-pathological correlation analysis, co-occurrence matrix, run-length matrix, and histogram analysis were performed to assess the relationship between pathological findings T1- and T2-weighted images (T1-WI and T2-WI). Results: All nine lesions ranged in size from 20 to 36 mm. Seven lesions were located in the superior portion of the retrobulbar space found outside of the muscle cone, and two lesions in the inferior portion were located within it. No significant correlation was observed between the amount of collagenous tissue and the qualitative evaluation of the signal on T1-WI and T2-WI. Kurtosis on T2-WI was significantly correlated with the amount of collagenous tissue ('ρ' = –0.97, 'p' < 0.0001) and endothelial cells ('ρ' = –0.49, 'p' = 0.0479). Conclusion: Kurtosis in the histogram analysis on T2WI showed a strong correlation with the amount of collagenous tissue.

To compare the imaging characteristics of the volumetric-interpolated breath-hold examination (VIBE) using compressed-sensing (CS) acceleration (CS-VIBE) with the conventional sequence relying on parallel imaging to assess the potential use of CS-VIBE as a functional imaging technique for upper abdominal haemodynamics.Patients (30 men, 27 women) suspected of having a hepatic disease underwent magnetic resonance imaging (MRI) of the liver, including a dynamic contrast-enhanced study. Gadolinium-ethoxybenzyl-diethylenetriamine pentaacetic acid was used as the contrast agent. MRI data of two multi-phase breath-hold exams were used for intra-individual comparisons. The VIBE and CS-VIBE were performed on different days. Image quality in both sequences was qualitatively assessed by three experienced radiologists. Moreover, the contrast ratio (CR) of the aorta, portal vein, liver and pancreas to muscle tissue were measured as a quantitative assessment. For the CS-VIBE, a five-phase time-intensity curve (TIC) was created to evaluate haemodynamics. The measurement area included the pancreas, common hepatic artery, portal vein and superior mesenteric vein. The ratio of that area to the muscle tissue in the same cross section was used to create the TICs.The qualitative assessment showed that artefacts were significantly different between the VIBE and CS-VIBE sequences. This finding indicated that the conventional VIBE had fewer artefacts. The CR was significantly higher for the CS-VIBE than for the VIBE images in all phases (p 0.001). An evaluation of haemodynamics compared with those obtained by CT angiography showed almost the same temporal characteristics in the common hepatic artery, portal vein and superior mesenteric vein signals as those in a previous study.Compared with the conventional VIBE, the CS-VIBE had significantly higher temporal resolution and higher image contrast. The temporal resolution of the CS-VIBE was sufficient for viewing abdominal haemodynamics. If the remaining limitation of acquisition speed for dynamic MRI can be adequately addressed, we believe that CS-VIBE functional images with high-contrast haemodynamics will be very useful in clinical practise.

Background Dynamic susceptibility contrast MR imaging (DSC-MRI) offers direct evaluation of neo-vascularity. Ferucarbotran does not accumulate in the interstitial space, instead remaining in the intravascular space during early phase imaging. We investigate tracer kinetic analysis with DSC-MRI with ferucarbotran and single level CT during hepatic arteriography (SL-CTHA) in assessment of hypervascular hepatocellular lesions and evaluate the usefulness of DSC-MRI with ferucarbotran. Methods Six patients having hypervascular hepatocellular carcinoma (HCC) and 3 patients having focal nodular hyperplasia (FNH) were included in the study. SL-CTHA was performed with the infusion of 3 mL of contrast media at a rate of 1 mL/s and scanned at a rate of 0.8 second per rotation. DSC-MRI was acquired with the echo-planar method at 1.5T system. A total dose of 1.4 mL (0.5 mol Fe/L) of ferucarbotran was used. Ferucarbotran was injected at a rate of 2 mL/s with 40 mL of physiological saline. Imaging was obtained at a temporal resolution of 1.2 or 0.46 seconds in 5 and 4 patients, respectively. For both CT and MRI modalities, a model-free analysis method was used to derive region of interest-based perfusion parameters. Plasma flow, distribution volume (DV) of contrast agent and estimated mean transit time (EMTT) were estimated. Results A strong correlation was obtained with plasma flow (r=0.8231, P=0.0064) between DSC-MRI and SL-CTHA. No significant correlation was obtained for DV and EMTT between DSC-MRI and SL-CTHA. All perfusion parameters showed no significant difference between SL-CTHA and DSC-MRI in FNH. On the other hand, in HCC, DV and EMTT showed significant differences (P=0.046 and 0.046), and plasma flow showed no significant difference between DSC-MRI and SL-CTHA. Conclusions This pilot study demonstrates the possibility of quantitative analysis of liver tumor using superparamagnetic iron oxide (SPIO)-based agent and highlights the potential for SPIO-based agent in more precisely assessing the perfusion characteristic of hypervascular liver tumors than by using extracellular contrast media.

Background Recently, diffusion-weighted imaging (DWI) and quantitative enhancement ratio measured at the hepatobiliary phase (HBP) of Gd-EOB-DTPA–enhanced magnetic resonance imaging (MRI) has been established as an effective method for evaluating liver fibrosis. Purpose To evaluate which is a more favorable surrogate marker in predicting high-stage liver fibrosis, apparently diffusion coefficient (ADC) value or quantitative enhancement ratio measured on HBP. Material and Methods Eighty-three patients with 99 surgically resected hepatic lesions were enrolled in this study. DWI was performed with b-values of 100 and 800 s/mm2. Regions of interest were set on ADC map, and the HBP of Gd-EOB-DTPA–enhanced MRI, to calculate ADC value, liver-to-muscle ratio (LMR), liver-to-spleen ratio (LSR), and contrast enhancement index (CEI) of liver. We compared these parameters between low-stage fibrosis (F0, F1, and F2) and high-stage fibrosis (F3 and F4). Receiver operating characteristic analysis was performed to compare the diagnostic performance when distinguishing low-stage fibrosis from high-stage fibrosis. Results LMR and CEI were significantly lower at high-stage fibrosis than at the low stage ( P Conclusion LMR and CEI were both adequate surrogate parameters to distinguish high-stage fibrosis from low-stage fibrosis.

SynGAP is a potent regulator of biochemical signaling in neurons and plays critical roles in neuronal function. It was first identified in 1998, and has since been extensively characterized as a mediator of synaptic plasticity. Because of its involvement in synaptic plasticity, SynGAP has emerged as a critical protein for normal cognitive function. In recent years, mutations in theSYNGAP1gene have been shown to cause intellectual disability in humans and have been linked to other neurodevelopmental disorders, such as autism spectrum disorders and schizophrenia. While the structure and biochemical function of SynGAP have been well characterized, a unified understanding of the various roles of SynGAP at the synapse and its contributions to neuronal function remains to be achieved. In this review, we summarize and discuss the current understanding of the multifactorial role of SynGAP in regulating neuronal function gathered over the last two decades.

SummarySynGAP is a synaptic Ras GTPase-activating protein (GAP) with four C-terminal splice variants: α1, α2, β, and γ. Although recent studies have implicatedSYNGAP1haploinsufficiency in ID/ASD pathogenesis, the degree to which each SynGAP isoform contributes to disease pathogenesis remains elusive. Here we demonstrate that individual SynGAP isoforms exhibit unique spatiotemporal expression and have distinct roles in neuronal and synaptic development. The SynGAP-α1 isoform, which undergoes robust liquid-liquid phase-separation with PSD-95 and is highly-enriched in synapses, is expressed late in development and disperses from synaptic spines in response to LTP-inducing synaptic activity to allow for AMPA receptor insertion and spine enlargement. In contrast, the SynGAP-β isoform, which undergoes less liquid-liquid phase-separation with PSD95 and is less synaptically targeted, is expressed early in development and promotes dendritic arborization. Interestingly, a SynGAP-α1 mutation that disrupts phase separation and synaptic targeting abolishes its function in plasticity and instead drives dendritic arbor development like the β isoform. These results demonstrate that distinct phase separation and synaptic targeting properties of SynGAP isoforms determine their function.HighlightsSynGAP-α1, α2, β, γ isoforms have distinct spatiotemporal expression and function in the brain.SynGAP-α1 is required for plasticity, while β is required for dendritic development.Liquid-liquid phase separation of SynGAP-α1 is required for its role in plasticity.SynGAP isoforms may differentially contribute to SYNGAP1 related human NDDs.

SummarySynGAP-α1 is a splice variant of the neurodevelopmental disorder risk gene, SYNGAP1/Syngap1. α1 encodes the C-terminal PDZ binding motif (PBM) that promotes liquid-liquid phase separation, a candidate process for postsynaptic density organization within excitatory synapses. However, it remains unknown how the endogenous SynGAP PBM regulates synapse properties and related cognitive functions. We found that a major PBM function in mice is to limit the mobility of SynGAP-α1 in response to NMDA receptor activation. Genetic disruption of the PBM increased SynGAP-α1 mobility to levels consistent with other non-PBM-containing C-terminal isoforms. This resulted in a lowering of the threshold for NMDA receptor-dependent signaling required for plasticity, leading to aberrant strengthening of excitatory synapses in spontaneously active neurons. PBM-deficient animals also exhibited a lower seizure threshold, disrupted LTP, and impaired cognition. Thus, the PBM enables isoform-specific SynGAP gating of NMDA receptor function, a mechanism linking synaptic signaling dynamics to network excitability and cognition.

Loss-of-function SYNGAP1 mutations cause a neurodevelopmental disorder characterized by intellectual disability and epilepsy. SYNGAP1 is a Ras-GTPase-activating protein that underlies the formation and experience-dependent regulation of postsynaptic densities. The mechanisms that contribute to this proposed monogenic cause of intellectual disability and epilepsy remain unresolved. Here, we establish the phenotype of the epileptogenesis in a Syngap1+/- mouse model using 24h video electroencephalogram/electromyogram (vEEG/EMG) recordings at advancing ages. A progressive worsening of clinically-similar seizure phenotypes, interictal spike frequency, sleep dysfunction, and hyperactivity was identified in Syngap1+/- mice. Interictal spikes emerged predominantly during NREM in 24h vEEG of Syngap1+/- mice. Myoclonic seizures occurred at behavioral-state transitions both in Syngap1+/- mice and during an overnight EEG from a child with SYNGAP1 haploinsufficiency. In Syngap1+/- mice, EEG spectral power analyses identified a significant loss of cortical gamma homeostasis during behavioral-state transitions from NREM to Wake and NREM to REM. The loss of gamma homeostasis was associated with a region- and location-specific significant increase of GluA2 AMPA receptor subunit expression in the somas of parvalbumin-positive (PV+) interneurons. Acute dosing with Perampanel, an FDA approved AMPA antagonist significantly rescued cortical gamma homeostasis, identifying a novel mechanism implicating Ca2+ impermeable AMPARs on PV+ interneurons underlying circuit dysfunction in SYNGAP1 haploinsufficiency.

Dynamin-related protein 1 (Drp1) divides mitochondria as a mechano-chemical GTPase. However, the function of Drp1 beyond mitochondrial division is largely unknown. Multiple Drp1 isoforms are produced through mRNA splicing. One such isoform, Drp1ABCD, contains all four alternative exons and is specifically expressed in the brain. Here, we studied the function of Drp1ABCD in mouse neurons in both culture and animal systems using isoform-specific knockdown by shRNA and isoform-specific knockout by CRISPR/Cas9. We found that the expression of Drp1ABCD is induced during postnatal brain development. Drp1ABCD is enriched in dendritic spines and regulates postsynaptic clathrin-mediated endocytosis by positioning the endocytic zone at the postsynaptic density, independently of mitochondrial division. Drp1ABCD loss promotes the formation of ectopic dendrites in neurons and enhanced sensorimotor gating behavior in mice. These data reveal that Drp1ABCD controls postsynaptic endocytosis, neuronal morphology and brain function.

The SynGAP protein is a major regulator of synapse biology and neural circuit function. Genetic variants linked to epilepsy and intellectual disability disrupt synaptic function and neural excitability. SynGAP has been involved in multiple signaling pathways and can regulate small GTPases with very different roles. Yet, the molecular bases behind this pleiotropy are poorly understood. We hypothesize that different SynGAP isoforms will mediate different sets of functions and that deciphering their spatio‐temporal expression and subcellular localization will accelerate understanding their multiple functions. Using isoform‐specific antibodies recognizing SynGAP in mouse and human samples we found distinctive developmental expression patterns for all SynGAP isoforms in five mouse brain areas. Particularly noticeable was the delayed expression of SynGAP‐α1 isoforms, which directly bind to postsynaptic density‐95, in cortex and hippocampus during the first 2 weeks of postnatal development. Suggesting that during this period other isoforms would have a more prominent role. Furthermore, we observed subcellular localization differences between isoforms, particularly throughout postnatal development. Consistent with previous reports, SynGAP was enriched in the postsynaptic density in the mature forebrain. However, SynGAP was predominantly found in non‐synaptic locations in a period of early postnatal development highly sensitive to SynGAP levels. While, α1 isoforms were always found enriched in the postsynaptic density, α2 isoforms changed from a non‐synaptic to a mostly postsynaptic density localization with age and β isoforms were always found enriched in non‐synaptic locations. The differential expression and subcellular distribution of SynGAP isoforms may contribute to isoform‐specific regulation of small GTPases, explaining SynGAP pleiotropy., Syngap1 gene encodes for different synaptic Ras/Rap GTPase‐activating (SynGAP) isoforms which are key for brain function. SynGAP C‐termini splice variants show different spatio‐temporal expression and subcellular localization in the developing mouse brain. This study reveals a non‐synaptic and heterogenous role of SynGAP spliced variants. Depicted abundance differences only allow relative comparison within a given tissue (top panel), postnatal age (PND, middle panel), or subcellular distribution (bottom panel). Ctx, cortex; Hip, hippocampus; Str, striatum; OB, Olfactory Bulb; Crb, cerebellum and tSynGAP, total SynGAP.

Objective: Dynamic contrast-enhanced MRI (DCE-MRI) can measure the changes in tumor blood flow, vascular permeability and interstitial and intravascular volume. The objective was to evaluate the efficacy of DCE-MRI in prediction of Barcelona Clinic Liver Cancer (BCLC) staging B or C hepatocellular carcinoma (HCC) response after treatment with transcatheter arterial chemoembolization (TACE) followed by sorafenib therapy.\ud \ud \ud \ud Methods: Sorafenib was administered four days after TACE of BCLC staging B or C HCC in 11 patients (21 lesions). DCE-MRI was performed with Gd-EOB-DTPA contrast before TACE and three and 10 days after TACE. DCE-MRI acquisitions were taken pre-contrast, hepatic arterial-dominant phase and 60, 120, 180, 240, 330, 420, 510 and 600 seconds post-contrast. Distribution volume of contrast agent (DV) and transfer constant Ktrans were calculated. Patients were grouped by mRECIST after one month or more post-TACE into responders (complete response, partial response) and non-responders (stable disease, progressive disease).\ud \ud \ud \ud Results: DV was reduced in responders at three and 10 days post-TACE (p = 0.008 and p = 0.008 respectively). DV fell in non-responders at three days (p = 0.025) but was not significantly changed from pre-TACE values after sorafenib. Sensitivity and specificity for DV 10 days post-TACE were 88% and 77% respectively.\ud \ud \ud \ud Conclusion: DV may be a useful biomarker for early prediction of therapeutic outcome in intermediate HCC.

SummarySynGAP is a Ras-GTPase activating protein highly enriched at excitatory synapses in the brain. Previous studies have shown that CaMKII and the RAS-ERK pathway are critical for several forms of synaptic plasticity including LTP. NMDA receptor-dependent calcium influx has been shown to regulate the RAS-ERK pathway and downstream events that result in AMPA receptor synaptic accumulation, spine enlargement, and synaptic strengthening during LTP. However, the cellular mechanisms whereby calcium influx and CaMKII control Ras activity remain elusive. Using live-imaging techniques, we have found that SynGAP is rapidly dispersed from spines upon LTP induction in hippocampal neurons, and this dispersion depends on phosphorylation of SynGAP by CaMKII. Moreover, the degree of acute dispersion predicts the maintenance of spine enlargement. Thus, the synaptic dispersion of SynGAP by CaMKII phosphorylation during LTP represents a key signaling component that transduces CaMKII activity to small G protein-mediated spine enlargement, AMPA receptor synaptic incorporation, and synaptic potentiation.

The neural type I membrane protein Alcadein α (Alcα), is primarily cleaved by amyloid β-protein precursor (APP) α-secretase to generate a membrane-associated carboxyl-terminal fragment (Alcα CTF), which is further cleaved by γ-secretase to secrete p3-Alcα peptides and generate an intracellular cytoplasmic domain fragment (Alcα ICD) in the late secretory pathway. By association with the neural adaptor protein X11L (X11-like), Alcα and APP form a ternary complex that suppresses the cleavage of both Alcα and APP by regulating the transport of these membrane proteins into the late secretory pathway where secretases are active. However, it has not been revealed how Alcα and APP are directed from the ternary complex formed largely in the Golgi into the late secretory pathway to reach a nerve terminus. Using a novel transgenic mouse line expressing excess amounts of human Alcα CTF (hAlcα CTF) in neurons, we found that expression of hAlcα CTF induced excess production of hAlcα ICD, which facilitated APP transport into the nerve terminus and enhanced APP metabolism, including Aβ generation. In vitro cell studies also demonstrated that excess expression of Alcα ICD released both APP and Alcα from the ternary complex. These results indicate that regulated intramembrane proteolysis of Alcα by γ-secretase regulates APP trafficking and the production of Aβ in vivo.

It is unknown what occurs if both mitochondrial division and fusion are completely blocked. Here, we introduced mitochondrial stasis by deleting two dynamin-related GTPases for division (Drp1) and fusion (Opa1) in livers. Mitochondrial stasis rescues liver damage and hypotrophy caused by the single knockout (KO). At the cellular level, mitochondrial stasis re-establishes mitochondrial size and rescues mitophagy defects caused by division deficiency. Using Drp1KO livers, we found that the autophagy adaptor protein p62/sequestosome-1-which is thought to function downstream of ubiquitination-promotes mitochondrial ubiquitination. p62 recruits two subunits of a cullin-RING ubiquitin E3 ligase complex, Keap1 and Rbx1, to mitochondria. Resembling Drp1KO, diet-induced nonalcoholic fatty livers enlarge mitochondria and accumulate mitophagy intermediates. Resembling Drp1Opa1KO, Opa1KO rescues liver damage in this disease model. Our data provide a new concept that mitochondrial stasis leads the spatial dimension of mitochondria to a stationary equilibrium and a new mechanism for mitochondrial ubiquitination in mitophagy.

Here, Lim et al. present a fast cost-effective lentivirus-based rapid gene replacement method to interrogate the physiopathology of BRaf and ∼50 disease-linked BRaf mutants, including all CFC-linked mutants. This study establishes the first efficient procedure that permits large-scale functional analysis of human disease-linked mutations essential for precision medicine.

APP associates with kinesin-1 via JIP1. In JIP1-decicient neurons, the fast velocity and high frequency of anterograde transport of APP cargo are impaired to reduced velocity and lower frequency, respectively. Interaction of JIP1 with KLC via two novel elements in JIP1 plays an important role in efficient APP axonal transport., Alzheimer's β-amyloid precursor protein (APP) associates with kinesin-1 via JNK-interacting protein 1 (JIP1); however, the role of JIP1 in APP transport by kinesin-1 in neurons remains unclear. We performed a quantitative analysis to understand the role of JIP1 in APP axonal transport. In JIP1-deficient neurons, we find that both the fast velocity (∼2.7 μm/s) and high frequency (66%) of anterograde transport of APP cargo are impaired to a reduced velocity (∼1.83 μm/s) and a lower frequency (45%). We identified two novel elements linked to JIP1 function, located in the central region of JIP1b, that interact with the coiled-coil domain of kinesin light chain 1 (KLC1), in addition to the conventional interaction of the JIP1b 11–amino acid C-terminal (C11) region with the tetratricopeptide repeat of KLC1. High frequency of APP anterograde transport is dependent on one of the novel elements in JIP1b. Fast velocity of APP cargo transport requires the C11 domain, which is regulated by the second novel region of JIP1b. Furthermore, efficient APP axonal transport is not influenced by phosphorylation of APP at Thr-668, a site known to be phosphorylated by JNK. Our quantitative analysis indicates that enhanced fast-velocity and efficient high-frequency APP anterograde transport observed in neurons are mediated by novel roles of JIP1b.

Introduction: To evaluate the effect of increasing portal flow due to food intake on the parameters of Intravoxel Incoherent Motion (IVIM) and T2* relaxation time in healthy liver. Materials and methods: The subjects consisted of 15 healthy volunteers. We used a 1.5 T MRI system. All subjects received MRI three times as follows: after overnight fasting but before food intake, at 30 min, and at 4 h after food intake. MRI was repeated at a greater than 1 week interval. All subjects had 800 kcal of Calorie Mate. The echoplanar diffusion-weighted imaging was performed under free breathing and 10 b-values (0, 10, 20, 30, 50, 80, 100, 200, 400, 800 s/mm2) were obtained. T2*-weighted imaging with multi-echo gradient-echo sequence was performed with Siemens MapIt software under breath-holding. The portal flow measurement was performed with phase contrast sequence. The parameters of IVIM including ADC, DC, D*, and PF were calculated and T2* relaxation time was obtained using MapIt. Results: The portal blood flow increased significantly 30 min after food intake (P

Background To evaluate the usefulness of differentiation of histological grade in hepatocellular carcinoma (HCC) using three-dimensional (3D) analysis of apparent diffusion coefficient (ADC) histograms retrospectively. Methods The subjects consisted of 53 patients with 56 HCCs. The subjects included 12 well-differentiated, 35 moderately differentiated, and nine poorly differentiated HCCs. Diffusion-weighted imaging (b-values of 100 and 800 s/mm2) were obtained within 3 months before surgery. Regions of interest (ROIs) covered the entire tumor. The data acquired from each slice were summated to derive voxel-by-voxel ADCs for the entire tumor. The following parameters were derived from the ADC histogram: mean, standard deviation, minimum, maximum, mode, percentiles (5th, 10th, 25th, 50th, 75th, and 90th), skew, and kurtosis. These parameters were analyzed according to histological grade. After eliminating steatosis lesions, these parameters were re-analyzed. Results A weak correlation was observed in minimum ADC and 5th percentile for each histological grade (r = –0.340 and r = –0.268, respectively). The minimum ADCs of well, moderately, and poorly differentiated HCC were 585 ± 388, 411 ± 278, and 235 ± 102 × 10−6 mm2/s, respectively. Minimum ADC showed significant differences among tumor histological grades (P = 0.009). The minimum ADC of poorly differentiated HCC and that of combined well and moderately differentiated HCC were 236 ± 102 and 437 ± 299 × 10−6 mm2/s. The minimum ADC of poorly differentiated HCC was significantly lower than that of combined well and moderately differentiated HCC (P = 0.001). The sensitivity and specificity, when a minimum ADC of 400 × 10−6 mm2/s or lower was considered to be poorly differentiated HCC, were 100 and 54%, respectively. After exclusion of the effect of steatosis, the sensitivity and specificity did not change, although the statistical differences became strong (P

Objective: An ADC histogram which was derived from the Region of Interest (ROI) set over the entire tumor may distinguish thymoma from thymic cancer and provide less bias and reproducibility. To evaluate the utility of ADC histogram analysis for differentiating thymic cancer from thymoma in comparison with conventional MRI findings. Materials and methods: The subjects consisted of 31 patients with 27 thymomas and 4 thymic cancers. Diffusionweighted imaging was performed with b values of 100 and 800 s/mm2. Data acquired from each slice were summed up to derive voxel-by-voxel ADC values for the entire tumor and an ADC histogram was generated. The mean, standard deviation, minimum, maximum, 5th, 25th, 50th, 75th, 90th percentiles, mode, skewness, and kurtosis were derived from the ADC histogram. MRI findings were evaluated in terms of contour, capsulization, septum, hemorrhage, necrosis or cystic change, lymph node swelling, pleural effusion, major vascular invasion, and homogeneity. Results: Significant differences were observed in the minimum ADC, contour, and major vascular invasion between thymoma and thymic cancer (p=0.010, p=0.03, and p=0.009, respectively). The sensitivities and specificities when the minimum ADC was 70 × 10−6 mm2/s or lower, when the contour was lobular or irregular, and when the presence of vascular invasion was considered to be thymic cancer were 75% and 93%, 100% and 37%, and 25% and 100%, respectively. Conclusion: Minimum ADC was useful for distinguishing thymic cancer from thymoma, and it had an additional value to the routine MRI sequence.

Rapid advances in genetics are linking mutations on genes to diseases at an exponential rate, yet characterizing the gene-mutation-cell-behavior relationships essential for precision medicine remains a daunting task. More than 350 mutations on BRaf are associated with various tumors, and ∼40 mutations are associated with the neurodevelopmental disorder cardio–facio–cutaneous syndrome (CFC). We developed a fast cost-effective lentivirus-based rapid gene replacement method to interrogate the physiopathology of BRaf and ∼50 disease-linked BRaf mutants, including all CFC-linked mutants. Analysis of simultaneous multiple patch-clamp recordings from 6068 pairs of rat neurons with validation in additional mouse and human neurons and multiple learning tests from 1486 rats identified BRaf as the key missing signaling effector in the common synaptic NMDA-R–CaMKII–SynGap–Ras–BRaf–MEK–ERK transduction cascade. Moreover, the analysis creates the original big data unveiling three general features of BRaf signaling. This study establishes the first efficient procedure that permits large-scale functional analysis of human disease-linked mutations essential for precision medicine.

Purpose: To evaluate liver function obtained by tracer-kinetic modeling of dynamic contrast-enhanced magnetic resonance imaging (DCE-MRI) data acquired with a routine gadolinium ethoxybenzyl diethylenetriamine pentaacetic acid (Gd-EOB-DTPA)-enhanced protocol. Materials and Methods: Data were acquired from 25 cases of nonchronic liver disease and 94 cases of cirrhosis. DCE-MRI was performed with a dose of 0.025 mmol/kg Gd-EOB-DTPA injected at 2 mL/sec. A 3D breath-hold sequence acquired 5 volumes of 72 slices each: precontrast, double arterial phase, portal phase, and 4-minute postcontrast. Regions of interest (ROIs) were selected semiautomatically in the aorta, portal vein, and whole liver on a middle slice. A constrained dual-inlet two-compartment uptake model was fitted to the ROI curves, producing three parameters: intracellular uptake rate (UR), extracellular volume (Ve), and arterial flow fraction (AFF). Results: Median UR dropped from 4.46 10−2 min−1 in the noncirrhosis to 3.20 in Child–Pugh A (P = 0.001), and again to 1.92 in Child–Pugh B (P < 0.0001). Median Ve dropped from 6.64 mL 100 mL−1 in the noncirrhosis to 5.80 in Child–Pugh A (P = 0.01). Other combinations of Ve and AFF changes were not significant for any group. Conclusion: UR obtained from tracer kinetic analysis of a routine DCE-MRI has the potential to become a novel index of liver function. J. Magn. Reson. Imaging 2013;37:1109–1114. © 2012 Wiley Periodicals, Inc.

Kinesin-1 anterogradely transports vesicles containing cargo proteins when a protein-protein interaction activates it from an inhibited state. The C-terminal cytoplasmic region of kinesin-1 cargo protein Alcadeinα (Alcα) interacts with the KLC1 subunit's tetratricopeptide repeat (TPR) region, activating kinesin-1's association with vesicles and anterograde transport. We found that either of two 10-amino-acid WD motifs in Alcα cytoplasmic region was necessary and sufficient to initiate this activation. An artificial transmembrane protein containing either WD motif induced kinesin-1's vesicular association and anterograde transport in a KLC-dependent manner, even in the normally inhibiting presence of excess KLC1, thus allowing us to analyze the KLC1 TPR-WD functional interaction in detail in vivo. A part of TPR region was dispensable for the WD motifs' activation of kinesin-1 and transport, indicating that only part of the TPR structure is required for this function in vivo. For a different kinesin-1 cargo protein, JIP1, an 11-amino-acid C-terminal region was sufficient to recruit KLC1 to vesicles, but did not activate transport. These observations suggest that structurally different TPR-interacting peptides may have different effects on kinesin-1. This mechanism may partly explain how kinesin-1 can organize the transport of a wide variety of cargo molecules.

The most common pathogenesis for familial Alzheimer's disease (FAD) involves misprocessing/alternative processing of the amyloid precursor protein (APP) by γ-secretase (for review, see Gandy1 and Small and Gandy2). This misprocessing/alternative processing leads to a relative increase in the ratio of the level of a minor γ-secretase reaction product, amyloid-β42 (Aβ42), to that of the major reaction product, amyloid-β40 (Aβ40; Borchelt and colleagues3). Until now, little has been known about γ-secretase function in sporadic AD (SAD). We approached this issue by studying the metabolite peptides, p3-Alcα, that are derived from the processing by α-secretases and γ-secretases of the alcadeinα (Alcα), member of the alcadein (Alc) protein family. Alc proteins colocalize with APP in healthy mouse and SAD human brain,4 but they are entirely distinct from APP in their polypeptide sequence. In neurons, Alc proteins are complexed to APP via X11L adaptor molecules, raising the possibility that Alcs might be sorted and processed together with APP. Experimental evidence supports this reasoning. In the absence of X11L, both Alc and APP proteins are rapidly metabolized by proteolysis.5 Levels of the endogenous APP metabolite, Aβ, are elevated in the brains of X11L-deficient mice.6,7 Thus, taken together with similarities in their structure and cellular distribution, APP and Alc proteins would be predicted to undergo parallel metabolic fates (for APP and X11L, see Gandy1 and Suzuki and Nakaya8; for Alc, see Araki and colleagues,4,5,9). Alc proteins exist in mammalian neurons as 4 isoforms4: Alcα1, Alcα2, Alcβ, and Alcγ. Alcα, Alcβ, and Alcγ are encoded by independent genes, while Alcα1 and Alcα2 are splice variants derived from the Alcα gene. All 3 members of the Alc family (Alcα, Alcβ, and Alcγ) are cleaved by ADAM 10 and ADAM 17, which have been identified as the α-secretases for APP.10–13 Subsequent cleavage of the remaining Alc C-terminal fragments involves predominantly the presenilin 1-(PS1)-dependent γ-secretase, and this reaction liberates a short peptide that we have designated p3-Alcα into cell-conditioned media and into cerebrospinal fluid (CSF). The amino acid sequences of the various alternatively cleaved p3-Alcα peptides in human CSF are shown with those of APP-p3 and Aβ (Fig 1). The current study is based on the hypothesis that examination of AD-related processing of p3-Alcα might reveal evidence for γ-secretase dysfunction in SAD. In so doing, we seek to confirm and extend the report of Yanagida and colleagues,14 who described similar alternative processing of another γ-secretase substrate, APLP. Taken together with the data from Yanagida and colleagues,14 we suggest that multiple γ-secretase substrates are subjected to altered processing in SAD and that this potentially implicates an “acquired” γ-secretase dysfunction that might contribute the pathogenesis of SAD. Figure 1 Amino acid sequences and cleavage sites of p3-Alcα and Aβ in human CSF. The amino acid sequences of p3-Alcα (black-underline) along with the sequences of p3 (gray double-underline) and Aβ40 (black double-underline) of APP. ...

The X11/MINT family proteins are adaptor scaffolding proteins involved in formation of multiprotein complexes, and trafficking and metabolism of membrane proteins such as the beta-amyloid precursor protein. We found that a significant portion of X11L and X11L2 are recovered in nuclear fraction of mouse brain homogenates. EGFP-X11s were not detected in the nucleus of N2a neuroblastoma cells; however, administration of leptomycin B (LMB) induced substantial nuclear accumulation of EGFP-X11L and EGFP-X11L2, while EGFP-X11 showed little accumulation. Fluorescence loss in photobleaching (FLIP) analysis indicated that EGFP-X11L2 and EGFP-X11L are shuttled between the cytoplasm and nucleus, the former more effectively than the latter. We identified a nuclear export signal (NES) in the N-terminus of X11L2, mutation of which induces nuclear accumulation of EGFP-X11L2 in the absence of LMB. X11L2 fused to the Gal4 DNA binding domain (DBD) showed transcriptional activity, suggesting that X11L2 could function as a transcriptional activator if tethered near a promoter. Interestingly, attenuation of the nucleo-cytoplasmic shuttling of GAL4-DBD-X11L2 by mutating the NES or attaching the SV40 nuclear localization signal significantly decreased the apparent transcriptional activity. Our observations suggest that X11L2 functions in the nucleus by a mechanism distinct from conventional transactivators.

Alcadeinalpha (Alcalpha) is an evolutionarily conserved type I membrane protein expressed in neurons. We show here that Alcalpha strongly associates with kinesin light chain (K(D) approximately 4-8x10(-9) M) through a novel tryptophan- and aspartic acid-containing sequence. Alcalpha can induce kinesin-1 association with vesicles and functions as a novel cargo in axonal anterograde transport. JNK-interacting protein 1 (JIP1), an adaptor protein for kinesin-1, perturbs the transport of Alcalpha, and the kinesin-1 motor complex dissociates from Alcalpha-containing vesicles in a JIP1 concentration-dependent manner. Alcalpha-containing vesicles were transported with a velocity different from that of amyloid beta-protein precursor (APP)-containing vesicles, which are transported by the same kinesin-1 motor. Alcalpha- and APP-containing vesicles comprised mostly separate populations in axons in vivo. Interactions of Alcalpha with kinesin-1 blocked transport of APP-containing vesicles and increased beta-amyloid generation. Inappropriate interactions of Alc- and APP-containing vesicles with kinesin-1 may promote aberrant APP metabolism in Alzheimer's disease.

遮根シートを用いた夏作ハウスメロンの根域制限栽培において定植期以後のかん水方法の違いが地上部・地下部の生育, 根系分布に及ぼす影響を検討した. かん水処理は4処理区 (C区: 慣行地床栽培, 定植前うね全面かん水・少量多回数かん水管理, MF区: 根域制限・定植前うね全面かん水・多量少回数かん水管理, LM区: 根域制限・定植前うね全面かん水・少量多回数かん水管理, SD区: 根域制限・定植前うね中央部のみかん水・少量多回数かん水管理) を設けて植え付け直前の時期から処理を開始し, 収穫直後に各処理区の生育, 根系分布を調査した. C区での根系は分布が浅く, うね内だけでなく, 通路部分にも多くの根が分布した. 根域制限を行ったMF区, LM区でも浅根性の傾向が強く, LM区に比べてMF区での根量が少なかった. 一方, SD区では, 根域全体に太根, 細根が広がり, 根量もMF区, LM区に比べて多かった. 果実肥大はC区, SD区が優れ, 大玉で糖度も高かった. これに対してLM区, MF区は糖度は十分であるが, 果重がやや小さかった. また, 根域制限区の果梗長はいずれも品質基準内にとどまったが, LM区で最も短かった. 根域制限下における根系形成は地床栽培とは異なるだけでなく, かん水方法の違いによっても大きく変化し, 地上部生育, 果実の肥大・品質に影響を及ぼした.

Alzheimer's disease (AD) is a common neurodegenerative disorder that causes senile dementia. The pathological characteristics are the appearance of neurofibrillary tangles comprising abnormally phosphorylated tau and senile plaques composed of amyloid beta-protein depositions. Amyloid beta-protein precursor (APP) and presenilin (PS) are known to be causative genes of familial AD. Recent analyses have documented that APP functions in the axonal transport of vesicles and PS regulates intracellular protein trafficking. Dystrophic neurites, in which APP and Alcadein accumulate in swollen axons, are also observed in AD brain. These pathological characteristics and the features of AD-related proteins suggest that AD is a disease of the vesicular transport system. Here we review recent progress of research on AD pathogenesis from the viewpoint of membrane trafficking.

Previously we found that X11-like protein (X11L) associates with amyloid beta-protein precursor (APP). X11L stabilizes APP metabolism and suppresses the secretion of the amyloid beta-protein (Abeta) that are the pathogenic agents of Alzheimer's disease (AD). Here we found that Alcadein (Alc), a novel membrane protein family that contains cadherin motifs and originally reported as calsyntenins, also interacted with X11L. Alc was abundant in the brain and occurred in the same areas of the brain as X11L. X11L could simultaneously associate with APP and Alc, resulting in the formation of a tripartite complex in brain. The tripartite complex stabilized intracellular APP metabolism and enhanced the X11L-mediated suppression of Abeta secretion that is due to the retardation of intracellular APP maturation. X11L and Alc also formed another complex with C99, a carboxyl-terminal fragment of APP cleaved at the beta-site (CTFbeta). The formation of the Alc.X11L.C99 complex inhibited the interaction of C99 with presenilin, which strongly suppressed the gamma-cleavage of C99. In AD patient brains, Alc and APP were particularly colocalized in dystrophic neurites in senile plaques. Deficiencies in the X11L-mediated interaction between Alc and APP and/or CTFbeta enhanced the production of Abeta, which may be related to the development or progression of AD.

Drug discovery in psychiatry has been limited to chemical modifications of compounds originally discovered serendipitously. Therefore, more mechanism-oriented strategies of drug discovery for mental disorders are awaited. Schizophrenia is a devastating mental disorder with synaptic disconnectivity involved in its pathophysiology. Reduction in the dendritic spine density is a major alteration that has been reproducibly reported in the cerebral cortex of patients with schizophrenia. Disrupted-in-Schizophrenia-1 (DISC1), a factor that influences endophenotypes underlying schizophrenia and several other neuropsychiatric disorders, has a regulatory role in the postsynaptic density in association with the NMDA-type glutamate receptor, Kalirin-7, and Rac1. Prolonged knockdown of DISC1 leads to synaptic deterioration, reminiscent of the synaptic pathology of schizophrenia. Thus, we tested the effects of novel inhibitors to p21-activated kinases (PAKs), major targets of Rac1, on synaptic deterioration elicited by knockdown expression of DISC1. These compounds not only significantly ameliorated the synaptic deterioration triggered by DISC1 knockdown but also partially reversed the size of deteriorated synapses in culture. One of these PAK inhibitors prevented progressive synaptic deterioration in adolescence as shown by in vivo two-photon imaging and ameliorated a behavioral deficit in prepulse inhibition in adulthood in a DISC1 knockdown mouse model. The efficacy of PAK inhibitors may have implications in drug discovery for schizophrenia and related neuropsychiatric disorders in general.

In order to accumulate fundamental data on the atmospheric environments in subway, the mass concentration, particle size distribution and elemental constitution of suspended particulate matter (SPM), and the concentration and constitution of polycyclic aromatic hydrocarbon (PAH), were measured and analyzed at three subway stations with different air supply systems on the same line. The mass concentration of SPM in the subway stations showed seasonal variations, and was higher in December and October than in March and June. It was also higher at the subway stations than in the aboveground throughout the seasons. The concentrations of SPM in the size range of 0.5–5.0 μm were higher in the subway stations than aboveground, suggesting this size of SPM was generated by the operation of trains. The elements that were observed at high concentrations in the subway SPM were Fe, Ba, Cu and Ca. On the other hand, the elements of which concentrations were relatively higher in the aboveground air were Cl, Na and K. Po...