Astrocyte-targeting therapy rescues cognitive impairment caused by neuroinflammation via the Nrf2 pathway.

Neuroinflammation is a common feature of neurodegenerative disorders such as Alzheimer's disease (AD). Neuroinflammation is induced by dysregulated glial activation, and astrocytes, the most abundant glial cells, become reactive upon neuroinflammatory cytokines released from microglia and actively contribute to neuronal loss. Therefore, blocking reactive astrocyte functions is a viable strategy to manage neurodegenerative disorders. However, factors or therapeutics directly regulating astrocyte subtypes remain unexplored. Here, we identified transcription factor NF-E2-related factor 2 (Nrf2) as a therapeutic target in neurotoxic reactive astrocytes upon neuroinflammation. We found that the absence of Nrf2 promoted the activation of reactive astrocytes in the brain tissue samples obtained from AD model 5xFAD mice, whereas enhanced Nrf2 expression blocked the induction of reactive astrocyte gene expression by counteracting NF-κB subunit p65 recruitment. Neuroinflammatory astrocytes robustly up-regulated genes associated with type I interferon and the antigen-presenting pathway, which were suppressed by Nrf2 pathway activation. Moreover, impaired cognitive behaviors observed in AD mice were rescued upon ALGERNON2 treatment, which potentiated the Nrf2 pathway and reduced the induction of neurotoxic reactive astrocytes. Thus, we highlight the potential of astrocyte-targeting therapy by promoting the Nrf2 pathway signaling for neuroinflammation-triggered neurodegeneration.

Transcriptomic dysregulation and autistic-like behaviors in Kmt2c haploinsufficient mice rescued by an LSD1 inhibitor.

Recent studies have consistently demonstrated that the regulation of chromatin and gene transcription plays a pivotal role in the pathogenesis of neurodevelopmental disorders. Among many genes involved in these pathways, KMT2C, encoding one of the six known histone H3 lysine 4 (H3K4) methyltransferases in humans and rodents, was identified as a gene whose heterozygous loss-of-function variants are causally associated with autism spectrum disorder (ASD) and the Kleefstra syndrome phenotypic spectrum. However, little is known about how KMT2C haploinsufficiency causes neurodevelopmental deficits and how these conditions can be treated. To address this, we developed and analyzed genetically engineered mice with a heterozygous frameshift mutation of Kmt2c (Kmt2c+/fs mice) as a disease model with high etiological validity. In a series of behavioral analyses, the mutant mice exhibit autistic-like behaviors such as impairments in sociality, flexibility, and working memory, demonstrating their face validity as an ASD model. To investigate the molecular basis of the observed abnormalities, we performed a transcriptomic analysis of their bulk adult brains and found that ASD risk genes were specifically enriched in the upregulated differentially expressed genes (DEGs), whereas KMT2C peaks detected by ChIP-seq were significantly co-localized with the downregulated genes, suggesting an important role of putative indirect effects of Kmt2c haploinsufficiency. We further performed single-cell RNA sequencing of newborn mouse brains to obtain cell type-resolved insights at an earlier stage. By integrating findings from ASD exome sequencing, genome-wide association, and postmortem brain studies to characterize DEGs in each cell cluster, we found strong ASD-associated transcriptomic changes in radial glia and immature neurons with no obvious bias toward upregulated or downregulated DEGs. On the other hand, there was no significant gross change in the cellular composition. Lastly, we explored potential therapeutic agents and demonstrate that vafidemstat, a lysine-specific histone demethylase 1 (LSD1) inhibitor that was effective in other models of neuropsychiatric/neurodevelopmental disorders, ameliorates impairments in sociality but not working memory in adult Kmt2c+/fs mice. Intriguingly, the administration of vafidemstat was shown to alter the vast majority of DEGs in the direction to normalize the transcriptomic abnormalities in the mutant mice (94.3 and 82.5% of the significant upregulated and downregulated DEGs, respectively, P < 2.2 × 10-16, binomial test), which could be the molecular mechanism underlying the behavioral rescuing. In summary, our study expands the repertoire of ASD models with high etiological and face validity, elucidates the cell-type resolved molecular alterations due to Kmt2c haploinsufficiency, and demonstrates the efficacy of an LSD1 inhibitor that might be generalizable to multiple categories of psychiatric disorders along with a better understanding of its presumed mechanisms of action.

Long-lasting housing environment manipulation and acute loss of environmental enrichment impact BALB/c mice behaviour in multiple functional domains.

Understanding environmental influences on individuals' behaviour is challenging. Here we have investigated the housing impact of 9 weeks of enriched environment (EE) and social isolation (SI) and the impact of abrupt deprivation of EE (enrichment removal: ER) on BALB/c mice. Compared with the widely used C57BL/6 strain in research, BALB/c synthesises serotonin less efficiently due to a genetic variation and thus may potentially represent human populations at higher risk of stress-related disorders. We assessed the effects of EE and SI by conducting a behavioural test battery and the effects of acute ER by monitoring homecage activities and social behaviour. We found that EE and SI impact BALB/c's physiological states and behavioural performances from lower to higher cognitive processes: increased body weight, increased rectal temperature, altered performance in motor and sensory tasks, the activity level in a novel environment and altered performance in tests of anxiety-like behaviour, stress-coping strategies and learning and memory. Furthermore, acute ER triggered stress/frustration-like behaviour in BALB/c, with increased aggression, increased social distancing and disrupted daily/nightly activities. Our results demonstrate that long-lasting housing manipulation such as EE and SI, impact behaviour via multilayered processes over a wide range of functional domains, and unforeseen change to a negative environment, ER, is a major stressor that causes behavioural and psychological consequences through environment-gene interactions, a model of direct relevance to human health.

α-Synuclein Spread from Olfactory Bulb Causes Hyposmia, Anxiety, and Memory Loss in BAC-SNCA Mice.

BACKGROUND: Patients with Parkinson's disease (PD) show motor symptoms as well as various non-motor symptoms. Postmortem studies of PD have suggested that initial alpha-synuclein (α-Syn) pathology develops independently in the olfactory bulb and lower brainstem, spreading from there stereotypically. However, it remains unclear how these two pathological pathways contribute to the clinicopathological progression of PD. OBJECTIVE: The objective of this study was to examine the clinicopathological contribution of α-Syn spread from the olfactory bulb. METHODS: We conducted pathological and behavioral analyses of human α-Syn bacterial artificial chromosome transgenic mice injected with α-Syn preformed fibrils into the bilateral olfactory bulb up to 10 months postinjection. RESULTS: α-Syn preformed fibril injections induced more widespread α-Syn pathology in the transgenic mice than that in wild-type mice. Severe α-Syn pathology in the transgenic mice injected with α-Syn preformed fibrils was initially observed along the olfactory pathway and later in the brain regions that are included in the limbic system and have connections with it. The α-Syn pathology was accompanied by regional atrophy, neuron loss, reactive astrogliosis, and microglial activation, which were remarkable in the hippocampus. Behavioral analyses revealed hyposmia, followed by anxiety-like behavior and memory impairment, but not motor dysfunction, depression-like behavior, or circadian rhythm disturbance. CONCLUSION: Our data suggest that α-Syn spread from the olfactory bulb mainly affects the olfactory pathway and limbic system as well as its related regions, leading to the development of hyposmia, anxiety, and memory loss in PD. © 2021 International Parkinson and Movement Disorder Society.

Heterochromatin protein 1γ deficiency decreases histone H3K27 methylation in mouse neurosphere neuronal genes.

Heterochromatin protein (HP) 1γ, a component of heterochromatin in eukaryotes, is involved in H3K9 methylation. Although HP1γ is expressed strongly in neural tissues and neural stem cells, its functions are unclear. To elucidate the roles of HP1γ, we analyzed HP1γ -deficient (HP1γ KO) mouse embryonic neurospheres and determined that HP1γ KO neurospheres tended to differentiate after quaternary culture. Several genes normally expressed in neuronal cells were upregulated in HP1γ KO undifferentiated neurospheres, but not in the wild type (WT). Compared to that in the control neurospheres, the occupancy of H3K27me3 was lower around the transcription start sites (TSSs) of these genes in HP1γ KO neurospheres, while H3K9me2/3, H3K4me3, and H3K27ac amounts remained unchanged. Moreover, amounts of the H3K27me2/3 demethylases, UTX, and JMJD3, were increased around the TSSs of these genes. Treatment with GSK-J4, an inhibitor of H3K27 demethylases, decreased the expression of genes upregulated in HP1γ KO neurospheres, along with an increase of H3K27me3 amounts. Therefore, in murine neurospheres, HP1γ protected the promoter sites of differentiated cell-specific genes against H3K27 demethylases to repress the expression of these genes. A better understanding of central cellular processes such as histone methylation will help elucidate critical events such as cell-specific gene expression, epigenetics, and differentiation.

Lactosylceramide synthases encoded by B4galt5 and 6 genes are pivotal for neuronal generation and myelin formation in mice.

It is uncertain which ß4-galactosyltransferase (ß4GalT; gene name, B4galt), ß4GalT-5 and/or ß4GalT-6, is responsible for the production of lactosylceramide (LacCer) synthase, which functions in the initial step of ganglioside biosynthesis. Here, we generated conditional B4galt5 knockout (B4galt5 cKO) mice, using Nestin-Cre mice, and crossed these with B4galt6 KO mice to generate B4galt5 and 6 double KO (DKO) mice in the central nervous system (CNS). LacCer synthase activity and major brain gangliosides were completely absent in brain homogenates from the DKO mice, although LacCer synthase activity was about half its normal level in B4galt5 cKO mice and B4galt6 KO mice. The DKO mice were born normally but they showed growth retardation and motor deficits at 2 weeks and died by 4 weeks of age. Histological analyses showed that myelin-associated proteins were rarely found localized in axons in the cerebral cortex, and axonal and myelin formation were remarkably impaired in the spinal cords of the DKO mice. Neuronal cells, differentiated from neurospheres that were prepared from the DKO mice, showed impairments in neurite outgrowth and branch formation, which can be explained by the fact that neurospheres from DKO mice could weakly interact with laminin due to lack of gangliosides, such as GM1a. Furthermore, the neurons were immature and perineuronal nets (PNNs) were poorly formed in DKO cerebral cortices. Our results indicate that LacCer synthase is encoded by B4galt5 and 6 genes in the CNS, and that gangliosides are indispensable for neuronal maturation, PNN formation, and axonal and myelin formation.

The role of CaMKII-Tiam1 complex on learning and memory.

A stimulation inducing long-term potentiation (LTP) of synaptic transmission induces a persistent expansion of dendritic spines, a phenomenon known as structural LTP (sLTP). We previously proposed that the formation of a reciprocally activating kinase-effector complex (RAKEC) between CaMKII and Tiam1, an activator of the small G-protein Rac1, locks CaMKII into an active conformation, which in turn maintains the phosphorylation status of Tiam1. This makes Rac1 persistently active, specifically in the stimulated spine. To understand the significance of the CaMKII-Tiam1 RAKEC in vivo, we generated a Tiam1 mutant knock-in mouse line in which critical residues for CaMKII binding were mutated into alanines. We confirmed the central role of this interaction on sLTP by observing that KI mice showed reduced Rac1 activity, had smaller spines and a diminished sLTP as compared to their wild-type littermates. Moreover, behavioral tests showed that the novel object recognition memory of these animals was impaired. We thus propose that the CaMKII-Tiam1 interaction regulates spine morphology in vivo and is required for memory storage.

An immunohistochemical, enzymatic, and behavioral study of CD157/BST-1 as a neuroregulator.

BACKGROUND: Recent rodent and human studies provide evidence in support of the fact that CD157, well known as bone marrow stromal cell antigen-1 (BST-1) and a risk factor in Parkinson's disease, also meaningfully acts in the brain as a neuroregulator and affects social behaviors. It has been shown that social behaviors are impaired in CD157 knockout mice without severe motor dysfunction and that CD157/BST1 gene single nucleotide polymorphisms are associated with autism spectrum disorder in humans. However, it is still necessary to determine how this molecule contributes to the brain's physiological and pathophysiological functions. METHODS: To gain fresh insights about the relationship between the presence of CD157 in the brain and its enzymatic activity, and aberrant social behavior, CD157 knockout mice of various ages were tested. RESULTS: CD157 immunoreactivity colocalized with nestin-positive cells and elements in the ventricular zones in E17 embryos. Brain CD157 mRNA levels were high in neonates but low in adults. Weak but distinct immunoreactivity was detected in several areas in the adult brain, including the amygdala. CD157 has little or no base exchange activity, but some ADP-ribosyl cyclase activity, indicating that CD157 formed cyclic ADP-ribose but much less nicotinic acid adenine dinucleotide phosphate, with both mobilizing Ca2+ from intracellular Ca2+ pools. Social avoidance in CD157 knockout mice was rescued by a single intraperitoneal injection of oxytocin. CONCLUSIONS: CD157 may play a role in the embryonic and adult nervous systems. The functional features of CD157 can be explained in part through the production of cyclic ADP-ribose rather than nicotinic acid adenine dinucleotide phosphate. Further experiments are required to elucidate how the embryonic expression of CD157 in neural stem cells contributes to behaviors in adults or to psychiatric symptoms.

Major glycan structure underlying expression of the Lewis X epitope in the developing brain is O-mannose-linked glycans on phosphacan/RPTPß.

Glycosylation is a major protein modification. Although proteins are glycosylated/further modulated by several glycosyltransferases during trafficking from the endoplasmic reticulum to the Golgi apparatus, a certain glycan epitope has only been detected on a limited number of proteins. Of these glycan epitopes, Lewis X is highly expressed in the early stage of a developing brain and plays important roles in cell-cell interaction. The Lewis X epitope is comprised of a trisaccharide (Galß1-4 (Fucα1-3) GlcNAc), and a key enzyme for the expression of this epitope is α1,3-fucosyltransferase 9. However, the scaffolding glycan structure responsible for the formation of the Lewis X epitope as well as its major carrier protein has not been fully characterized in the nervous system. Here we showed that the Lewis X epitope was mainly expressed on phosphacan/receptor protein tyrosine phosphatase ß (RPTPß) in the developing mouse brain. Expression of the Lewis X epitope was markedly reduced in ß1,4-galactosyltransferase 2 (ß4GalT2) gene-deficient mice, which indicated that ß4GalT2 is a major galactosyltransferase required for the Lewis X epitope. We also showed that the Lewis X epitope almost disappeared due to the knockout of protein O-mannose ß1,2-N-acetylglucosaminyltransferase 1, an N-acetylglucosaminyltransferase essential for the synthesis of O-mannosylated glycans, which indicated that the O-mannosylated glycan is responsible for presenting the Lewis X epitope. Since O-mannosylated glycans on phosphacan/RPTPß could also present human natural killer-1, another glycan epitope specifically expressed in the nervous system, our results revealed the importance of O-mannosylated glycan chains in the presentation of functional glycan epitopes in the brain.

CD38 is critical for social behaviour by regulating oxytocin secretion.

CD38, a transmembrane glycoprotein with ADP-ribosyl cyclase activity, catalyses the formation of Ca2+ signalling molecules, but its role in the neuroendocrine system is unknown. Here we show that adult CD38 knockout (CD38-/-) female and male mice show marked defects in maternal nurturing and social behaviour, respectively, with higher locomotor activity. Consistently, the plasma level of oxytocin (OT), but not vasopressin, was strongly decreased in CD38-/- mice. Replacement of OT by subcutaneous injection or lentiviral-vector-mediated delivery of human CD38 in the hypothalamus rescued social memory and maternal care in CD38-/- mice. Depolarization-induced OT secretion and Ca2+ elevation in oxytocinergic neurohypophysial axon terminals were disrupted in CD38-/- mice; this was mimicked by CD38 metabolite antagonists in CD38+/+ mice. These results reveal that CD38 has a key role in neuropeptide release, thereby critically regulating maternal and social behaviours, and may be an element in neurodevelopmental disorders.

Specific enzyme complex of beta-1,4-galactosyltransferase-II and glucuronyltransferase-P facilitates biosynthesis of N-linked human natural killer-1 (HNK-1) carbohydrate.

Human natural killer-1 (HNK-1) carbohydrate is highly expressed in the nervous system and is involved in synaptic plasticity and dendritic spine maturation. This unique carbohydrate, consisting of a sulfated trisaccharide (HSO(3)-3GlcAß1-3Galß1-4GlcNAc-), is biosynthesized by the successive actions of ß-1,4-galactosyltransferase (ß4GalT), glucuronyltransferase (GlcAT-P and GlcAT-S), and sulfotransferase (HNK-1ST). A previous study showed that mice lacking ß4GalT-II, one of seven ß4GalTs, exhibited a dramatic loss of HNK-1 expression in the brain, although ß4GalT-I-deficient mice did not. Here, we investigated the underlying molecular mechanism of the regulation of HNK-1 expression. First, focusing on a major HNK-1 carrier, neural cell adhesion molecule, we found that reduced expression of an N-linked HNK-1 carbohydrate caused by a deficiency of ß4GalT-II is not likely due to a general loss of the ß1,4-galactose residue as an acceptor for GlcAT-P. Instead, we demonstrated by co-immunoprecipitation and endoplasmic reticulum-retention analyses using Neuro2a (N2a) cells that ß4GalT-II physically and specifically associates with GlcAT-P. In addition, we revealed by pulldown assay that Golgi luminal domains of ß4GalT-II and GlcAT-P are sufficient for the complex to form. With an in vitro assay system, we produced the evidence that the kinetic efficiency k(cat)/K(m) of GlcAT-P in the presence of ß4GalT-II was increased about 2.5-fold compared with that in the absence of ß4GalT-II. Finally, we showed that co-expression of ß4GalT-II and GlcAT-P increased HNK-1 expression on various glycoproteins in N2a cells, including neural cell adhesion molecule. These results indicate that the specific enzyme complex of ß4GalT-II with GlcAT-P plays an important role in the biosynthesis of HNK-1 carbohydrate.

Alteration of stratum corneum ceramide profiles in spontaneous canine model of atopic dermatitis.

Ceramides (CERs) in the stratum corneum (SC) are thought to play a key role in cutaneous barrier function. It has been reported that human SC contains 11 free CER classes and that their profiles are altered in humans with atopic dermatitis (AD). Although decreased proportions of free CERs or quantities of protein-bound CERs in the SC have been reported in dogs with AD, the overall profile of CERs in the canine SC has not been fully elucidated. The aim of this study was thus to investigate the profile of free CERs in the canine SC and to identify alterations in the CER profiles in dogs with AD. Normal-phase liquid chromatography-electrospray ionization-mass spectrometry indicated 11 clusters of peaks for free CER classes, similar to those recognized in the human SC. The fractions of free SC CER in dogs with AD and in breed- and age-matched healthy dogs were quantitatively compared using high-performance thin-layer chromatography. CER[EOS], CER[EOP] and CER[NP], which are known to be decreased in the skin of humans with AD, were also decreased in the skin of dogs with AD. These findings highlight canine AD as a spontaneous animal model for investigating the disruption of CER-associated cutaneous barrier functions in the corresponding human disease.

Deficiency of the RIß subunit of protein kinase A causes body tremor and impaired fear conditioning memory in rats.

The RIß subunit of cAMP-dependent protein kinase (PKA), encoded by Prkar1b, is a neuronal isoform of the type I regulatory subunit of PKA. Mice lacking the RIß subunit exhibit normal long-term potentiation (LTP) in the Schaffer collateral pathway of the hippocampus and normal behavior in the open-field and fear conditioning tests. Here, we combined genetic, electrophysiological, and behavioral approaches to demonstrate that the RIß subunit was involved in body tremor, LTP in the Schaffer collateral pathway, and fear conditioning memory in rats. Genetic analysis of WTC-furue, a mutant strain with spontaneous tremors, revealed a deletion in the Prkar1b gene of the WTC-furue genome. Prkar1b-deficient rats created by the CRISPR/Cas9 system exhibited body tremor. Hippocampal slices from mutant rats showed deficient LTP in the Schaffer collateral-CA1 synapse. Mutant rats also exhibited decreased freezing time following contextual and cued fear conditioning, as well as increased exploratory behavior in the open field. These findings indicate the roles of the RIß subunit in tremor pathogenesis and contextual and cued fear memory, and suggest that the hippocampal and amygdala roles of this subunit differ between mice and rats and that rats are therefore beneficial for exploring RIß function.

Abnormal social behavior and altered gene expression in mice lacking NDRG2.

N-myc downstream-regulated gene 2 (NDRG2), a member of the NDRG family, has multiple functions in cell proliferation, differentiation, and stress responses, and is predominantly expressed by astrocytes in the central nervous system. Previous studies including ours demonstrated that NDRG2 is involved in various central nervous system pathologies. However, the significance of NDRG2 in neurodevelopment is not fully understood. Here, we investigated the expression profile of NDRG2 during postnatal brain development, the role of NDRG2 in social behavior, and transcriptome changes in the brain of NDRG2-deficient mice. NDRG2 expression in the brain increased over time from postnatal day 1 to adulthood. Deletion of NDRG2 resulted in abnormal social behavior, as indicated by reduced exploratory activity toward a novel mouse in a three-chamber social interaction test. Microarray analysis identified genes differentially expressed in the NDRG2-deficient brain, and upregulated gene expression of Bmp4 and Per2 was confirmed by quantitative PCR analysis. Expression of both these genes and the encoded proteins increased over time during postnatal brain development, similar to NDRG2. Gene expression of Bmp4 and Per2 was upregulated in cultured astrocytes isolated from NDRG2-deficient mice. These results suggest that NDRG2 contributes to brain development required for proper social behavior by modulating gene expression in astrocytes.

Muscle weakness and impaired motor coordination in hyperpolarization-activated cyclic nucleotide-gated potassium channel 1-deficient rats.

Hyperpolarization-activated cyclic nucleotide-gated potassium channel 1 (HCN1) contribute to spontaneous rhythmic activity in different tissues, including the heart and brain. Deficiency in HCN1 function is associated with sick sinus syndrome in mice and epilepsy in humans. We recently developed Hcn1-deficient rats and found that they exhibit absence epilepsy. While rearing Hcn1-deficient rats, we noticed loose muscle tension and abnormal gait. We therefore evaluated the muscle strength and motor functions of Hcn1-deficient rats. When subjected to the wire hang test, Hcn1-deficient rats fell down more easily than control F344 rats. Grip strength of Hcn1-deficient rats was significantly smaller than F344 rats. In the inclined plane test, they exhibited a smaller maximum angle. In the rotarod test, the latency to fall was shorter for Hcn1-deficient rats than F344 rats. In the footprint analysis, Hcn1-deficient rats exhibited smaller step length and wider step width than F344 rats. Instead of poor motor coordination ability and muscle weakness, Hcn1-deficient rats exhibited normal electromyograms, muscle histology, and deep tendon reflex. These findings suggest that HCN1 channels contribute to motor coordination and muscle strength, and that the muscle weakness of Hcn1-deficient rats results from the involvement not of the peripheral but of the central nervous system.

Increased transepidermal water loss and decreased ceramide content in lesional and non-lesional skin of dogs with atopic dermatitis.

This study evaluated changes in transepidermal water loss (TEWL), skin hydration and intercorneal lipid content in dogs with atopic dermatitis (AD). TEWL and skin hydration were measured in the inguinal skin of 10 dogs with AD and 30 normal dogs. TEWL was significantly higher in both lesional skin (94.3 +/- 38.8 g/m(2)/h) and non-lesional skin (28.8 +/- 9.5) of dogs with AD than healthy controls (12.3 +/- 2.3) (P < 0.05). Water content in the lesional skin of dogs with AD (15.8 +/- 7.0 AU) was significantly lower than that of controls (24.2 +/- 8.8) (P < 0.05), whereas no significant differences were recognized in water content between non-lesional skin of dogs with AD and controls. To compare the lipid content between lesional and non-lesional skin of dogs with AD and controls, intercorneal lipids, extracted from the stratum corneum, were quantified by thin-layer chromatography. The relative amounts of ceramides in the lesional skin (24.4 +/- 5.6%) and non-lesional skin (25.6 +/- 3.8%) of dogs with AD were significantly lower than those in controls (31.4 +/- 6.9%) (P < 0.05). Conversely, no significant differences were recognized in the relative amounts of cholesterols and free fatty acids (FFA) between dogs with AD and controls. Moreover, there are statistical correlations between TEWL and the relative amounts of ceramides, but not those of cholesterols and FFA, in both lesional and non-lesional skin of dogs with AD. These results strongly suggest that decreased ceramide content accelerates TEWL in dogs with AD, similar to the situation seen in the corresponding human disease.

Hes1 expression in mature neurons in the adult mouse brain is required for normal behaviors.

Hes1 regulates the maintenance and proliferation of neural stem/progenitor cells as an essential effector of the Notch signaling pathway. Although Notch signaling is also involved in the functions of mature neurons in learning and memory and in the risk factors for mental disorders such as schizophrenia and bipolar disorder, the in-vivo role of Hes1 in mature neurons remains unknown. Here, we found that Hes1 is expressed by subsets of both excitatory and inhibitory neurons in the adult mouse brain, and that Hes1 expression is induced by neuronal stimulation. Furthermore, inactivation of Hes1 in excitatory neurons resulted in abnormal fear and anxiety behaviors concomitantly with higher neuronal excitability in the amygdala, while inactivation of Hes1 in inhibitory neurons resulted in increased sociability and perseverative tendencies. These results indicated that Hes1 is functionally important for normal behaviors not only in excitatory neurons but also in inhibitory neurons in the adult brain.

Transepidermal water loss (TEWL) reflects skin barrier function of dog.

The correlation between skin barrier function and transepidermal water loss (TEWL) was evaluated in dogs. Stratum corneum (SC) of 10 healthy dogs was removed by tape stripping (TS), which decreased the corneal layer to allow for permeation of fluorescent dye into skin. TEWL of damaged skin was measured with the closed-chamber-type TEWL analyzer, CC-01. The frequency of TS was directly related to the decrease of SC and the increased permeation of fluorescent dye, and TEWL increased with increasing impairment of skin barrier function. The results suggest that increased TEWL reflects impaired canine skin barrier function.

Involvement of hippocampal metabotropic glutamate receptors in radial maze performance.

We investigated the role of hippocampal metabotropic glutamate receptors in spatial learning and memory, using an eight-arm radial maze task. (S)-4-Carboxyphenylglycine, a group I metabotropic glutamate receptor antagonist, or trans-(+/-)-1-amino-(1S,3R)-cyclopentanedicarboxylic acid, a broad-spectrum metabotropic glutamate receptor agonist, was administered into the dorsal hippocampus after rats had acquired the task. Both of these agents significantly impaired radial maze performance, suggesting a functional importance of hippocampal metabotropic glutamate receptors in spatial working memory.

A new method of measuring the transepidermal water loss (TEWL) of dog skin.

Human skin barrier function is evaluated by measuring transepidermal water loss (TEWL). However, this conventional method has not been applied to assess canine skin barrier function because the equipment is not suitable for dogs due to the effects of air turbulence resulting from movement of the subject and vapor from the subject's hair coat. The TEWL analyzer CC-01 was developed as a closed-chamber method device; this means that instead of using the open-chamber method, it has a ventilated chamber that uses dry air. TEWL values measured by CC-01 show less variability than those measured by the conventional method. An ambient temperature of 20-26 degrees C is optimal for measurement with the CC-01, and humidity affects the length of measurement but not the values. The CC-01 may be more reliable for measurement of TEWL than the conventional methods and may give new insights in the evaluation of skin barrier function in dogs.