Homer Proteins Research Articles

Effects of two inhibitors of metabolic glutamate receptor 5 on expression of endogenous homer scaffold protein 1 in the auditory cortex of mice with tinnitus

ABSTRACT Tinnitus is deemed as the result of abnormal neural activities in the brain, and Homer proteins are expressed in the brain that convey nociception. The expression of Homer in tinnitus has not been studied. We hypothesized that expression of Homer in the auditory cortex was altered after tinnitus treatment. Mice were injected with sodium salicylate to induce tinnitus. Expression of Homer was detected by quantitative real-time polymerase chain reaction, western blotting, and immunohistochemistry assays. We found that Homer1 expression was upregulated in the auditory cortex of mice with tinnitus, while expression of Homer2 or Homer3 exhibited no significant alteration. Effects of two inhibitors of metabolic glutamate receptor 5 (mGluR5), noncompetitive 2-Methyl-6-(phenylethynyl)-pyridine (MPEP) and competitive α-methyl-4-carboxyphenylglycine (MCPG), on the tinnitus scores of the mice and on Homer1 expression were detected. MPEP significantly reduced tinnitus scores and suppressed Homer1 expression in a concentration dependent manner. MCPG had no significant effects on tinnitus scores or Homer1 expression. In conclusion, Homer1 expression was upregulated in the auditory cortex of mice after tinnitus, and was suppressed by noncompetitive mGluR5 inhibitor MPEP, but not competitive mGluR5 inhibitor MCPG.

Multiple Rare Risk Coding Variants in Postsynaptic Density-Related Genes Associated With Schizophrenia Susceptibility.

ObjectiveSchizophrenia is a chronic debilitating neurobiological disorder of aberrant synaptic connectivity and synaptogenesis. Postsynaptic density (PSD)–related proteins in N-methyl-D-aspartate receptor–postsynaptic signaling complexes are crucial to regulating the synaptic transmission and functions of various synaptic receptors. This study examined the role of PSD-related genes in susceptibility to schizophrenia.MethodsWe resequenced 18 genes encoding the disks large-associated protein (DLGAP), HOMER, neuroligin (NLGN), neurexin, and SH3 and multiple ankyrin repeat domains (SHANK) protein families in 98 schizophrenic patients with family psychiatric history using semiconductor sequencing. We analyzed the protein function of the identified rare schizophrenia-associated mutants via immunoblotting and immunocytochemistry.ResultsWe identified 50 missense heterozygous mutations in 98 schizophrenic patients with family psychiatric history, and in silico analysis revealed some as damaging or pathological to the protein function. Ten missense mutations were absent from the dbSNP database, the gnomAD (non-neuro) dataset, and 1,517 healthy controls from Taiwan BioBank. Immunoblotting revealed eight missense mutants with altered protein expressions in cultured cells compared with the wild type.ConclusionOur findings suggest that PSD-related genes, especially the NLGN, SHANK, and DLGAP families, harbor rare functional mutations that might alter protein expression in some patients with schizophrenia, supporting contributing rare coding variants into the genetic architecture of schizophrenia.

Deficiencies of <i>Homer2</i> and <i>Homer3</i> accelerate aging-dependent bone loss in mice

Homer proteins are scaffold proteins that regulate calcium (Ca2+) signaling by modulating the activity of multiple Ca2+ signaling proteins. In our previous report, Homer2 and Homer3 regulated NFATc1 function through its interaction with calcineurin, which then acted to regulate receptor activator of nuclear factor-kappa B ligand (RANKL)-induced osteoclastogenesis and bone metabolism. However, to date, the role of Homers in osteoclastogenesis remains unknown. In this study, we investigated the roles of Homer2 and Homer3 in aging-dependent bone remodeling. Deletion of Homer2 /Homer3 (Homer2/3 DKO) markedly decreased the bone density of the femur. The decrease in bone density was not seen in mice with Homer2 (Homer2−/−) and Homer3 (Homer3−/−) deletion. Moreover, RANKL treatment of bone marrow-derived monocytes/macrophages in Homer2/3 DKO mice significantly increased the formation of multinucleated cells and resorption areas. Finally, Homer2/3 DKO mice decreased bone density in an aging-dependent manner. These findings suggest a novel potent mode of bone homeostasis regulation through osteoclasts differentiation during aging by Homer proteins, specifically Homer2 and Homer3.

Subchronic administration of auranofin reduced amyloid-β plaque pathology in a transgenic APPNL-G-F/NL-G-F mouse model

Alzheimer’s disease (AD) is the most common cause of dementia. Neuropathological processes, including the accumulation of amyloid-β (Aβ) plaques and neurofibrillary tangles, and neuroinflammation, lead to cognitive impairment at middle and eventually later stages of AD progression. Over the last decade, focused efforts have explored repurposed drug approaches for AD pathophysiological mechanisms. Recently, auranofin, an anti-inflammatory drug, was shown to have therapeutic potential in a number of diseases in addition to rheumatoid arthritis. Surprisingly, no data regarding the effects of auranofin on cognitive deficits in AD mice or the influence of auranofin on Aβ pathology and neuroinflammatory processes are available. In the present study, we used 14-month-old transgenic male APPNL-G-F/NL-G-F mice to assess the effects of subchronic administration of auranofin at low doses (1 and 5 mg/kg, intraperitoneal) on spatial memory, Aβ pathology and the expression of cortical and hippocampal proteins (glial fibrillary acidic protein (GFAP), ionized calcium binding adaptor molecule-1 (Iba-1)) and proteins related to synaptic plasticity (glutamic acid decarboxylase 67 (GAD67), homer proteins homologue-1 (Homer-1)). The data demonstrated that auranofin significantly decreased Aβ deposition in the hippocampus and the number of Aβ plaques in the cingulate cortex, but it did not have memory-enhancing effects or induce changes in the expression of the studied proteins. Our current results highlight the importance of considering further pre-clinical research to investigate the possible beneficial effects of auranofin on the other pathological aspects of AD.

A single nucleotide polymorphism in the HOMER1 gene is associated with sleep latency and theta power in sleep electroencephalogram.

Glutamate is the most excitatory neurotransmitter in the central nervous system and it is involved in the initiation and maintaining of waking and rapid-eye-movement (REM) sleep. Homer proteins act in the trafficking and/or clustering of metabotropic glutamate receptors, and polymorphisms in the HOMER1 gene have been associated with phenotypes related to glutamate signaling dysregulation. In this study, we report the association of a single nucleotide polymorphism (SNP) in the HOMER1 gene (rs3822568) with specific aspects of sleep in a sample of the Brazilian population. To accomplish this, 1,042 individuals were subjected to a full-night polysomnography, and a subset of 983 subjects had rs3822568 genotyping data available. When compared with the A allele carriers, GG genotyped individuals showed higher sleep latency, lower sleep efficiency, reduced number of arousals per hour, lower apnea-hypopnea index (AHI) and lower theta spectral power. In summary, the present findings suggest that the rs3822568 polymorphism in the HOMER1 gene is associated with sleep EEG profiles and might have an impact on sleep quality and sleep structure, with potential to explain inter-individual variation in sleep homeostasis.

Acute Sleep Loss Upregulates the Synaptic Scaffolding Protein, Homer1a, in Non-canonical Sleep/Wake Brain Regions, Claustrum, Piriform and Cingulate Cortices.

Homer proteins are a component of the post-synaptic density of neurons that are necessary for the maintenance and consolidation of behavioral state. The dominant negative protein homer1a is rapidly increased by neuronal activity and sleep loss. Homer1a knockout mice with globally absent homer1a have reduced ability to sustain wakefulness during the active period. It is not known whether homer1a is required globally or in very specific brain regions or neurons for its role in maintaining wake. In this study, we examined the expression of homer1a, an immediate early gene involved in intracellular signaling cascades, in mice subjected to extended wakefulness. We found that mice displayed increased expression of homer1a in the claustrum, a brain region thought to be involved in consciousness, as well as the cingulate and piriform cortices compared to non-sleep deprived mice. In situ hybridization (ISH) studies also indicate that homer1a is not induced in the known wake promoting regions with sleep deprivation, but is instead upregulated primarily in the claustrum and piriform cortex. Examination of homer1a expression levels with recovery sleep after sleep deprivation indicate that baseline homer1a expression levels were restored. Further, we have identified that homer1a is upregulated in excitatory neurons of the claustrum suggesting that homer1a promotes wakefulness through activating excitatory neurons. This work identifies regions previously unknown to be involved in sleep regulation that respond to acute sleep deprivation or enhanced waking.

Distinct and Overlapping Expression Patterns of the Homer Family of Scaffolding Proteins and Their Encoding Genes in Developing Murine Cephalic Tissues.

In mammals Homer1, Homer2 and Homer3 constitute a family of scaffolding proteins with key roles in Ca2+ signaling and Ca2+ transport. In rodents, Homer proteins and mRNAs have been shown to be expressed in various postnatal tissues and to be enriched in brain. However, whether the Homers are expressed in developing tissues is hitherto largely unknown. In this work, we used immunohistochemistry and in situ hybridization to analyze the expression patterns of Homer1, Homer2 and Homer3 in developing cephalic structures. Our study revealed that the three Homer proteins and their encoding genes are expressed in a wide range of developing tissues and organs, including the brain, tooth, eye, cochlea, salivary glands, olfactory and respiratory mucosae, bone and taste buds. We show that although overall the three Homers exhibit overlapping distribution patterns, the proteins localize at distinct subcellular domains in several cell types, that in both undifferentiated and differentiated cells Homer proteins are concentrated in puncta and that the vascular endothelium is enriched with Homer3 mRNA and protein. Our findings suggest that Homer proteins may have differential and overlapping functions and are expected to be of value for future research aiming at deciphering the roles of Homer proteins during embryonic development.

A psychiatric disease-related circular RNA controls synaptic gene expression and cognition

Although circular RNAs (circRNAs) are enriched in the mammalian brain, very little is known about their potential involvement in brain function and psychiatric disease. Here, we show that circHomer1a, a neuronal-enriched circRNA abundantly expressed in the frontal cortex, derived from Homer protein homolog 1 (HOMER1), is significantly reduced in both the prefrontal cortex (PFC) and induced pluripotent stem cell-derived neuronal cultures from patients with schizophrenia (SCZ) and bipolar disorder (BD). Moreover, alterations in circHomer1a were positively associated with the age of onset of SCZ in both the dorsolateral prefrontal cortex (DLPFC) and orbitofrontal cortex (OFC). No correlations between the age of onset of SCZ and linear HOMER1 mRNA were observed, whose expression was mostly unaltered in BD and SCZ postmortem brain. Using in vivo circRNA-specific knockdown of circHomer1a in mouse PFC, we show that it modulates the expression of numerous alternative mRNA transcripts from genes involved in synaptic plasticity and psychiatric disease. Intriguingly, in vivo circHomer1a knockdown in mouse OFC resulted in specific deficits in OFC-mediated cognitive flexibility. Lastly, we demonstrate that the neuronal RNA-binding protein HuD binds to circHomer1a and can influence its synaptic expression in the frontal cortex. Collectively, our data uncover a novel psychiatric disease-associated circRNA that regulates synaptic gene expression and cognitive flexibility.

Group I metabotropic glutamate receptors (mGluR1/5) and neurodegenerative diseases

This overview describes how group mGluR1/5 metabotropic glutamate receptors are involved in neurodegenerative diseases; it also touches upon their use as therapeutic targets in animal models. mGluR1/5 are primarily located on the neuronal postsynaptic membrane, where they communicate with two proteins, Gα q/11 and Homer, which, in turn, initiate several biochemical cascades. The Gα q/11 protein cascade includes Са 2+ release from the endoplasmic reticulum (ER) through the inositol trisphosphate receptors (IP 3 R) and the activation of depot-controlled Са 2+ entry. The Gα q/11 protein cascade also includes the production of diacylglycerol with subsequent activation of various protein kinases, which, in turn, provide influences on the genome. The Homer protein communicates directly with the NMDA receptors and Shank scaffold proteins, through which it regulates the activity of various protein kinases, including Akt and ERK1/2. The activation of mGluR1/5 triggers long-term depression of glutamatergic transmission through the endocytosis of AMPA receptors, caused by changes in the level of protein phosphorylation and genome activation. It is thought that mGluR1/5 play an important role in the development of neurodegenerative diseases. In Alzheimer's disease, mGluR1/5 acts as a target for the β-amyloid peptide. mGluR1/5 antagonists have a neuroprotective effect in transgenic mice with Alzheimer's disease. The pathogenesis of Alzheimer's disease includes increased Са 2+ release from the ER due to the pathological activity of mGluR1/5, as well as the influence of mutated presenilin on Са 2+ homeostasis in the ER. At the same time, restoration of Са 2+ levels in the ER is disrupted by the effect of presenilin on depot-activated Са 2+ entry. mGluR5 (but not mGluR1) is being studied as a potential therapeutic target in Parkinson's disease. Numerous studies on rodent and primate models of Parkinson's disease have demonstrated a significant antiparkinsonian effect when mGluR5 antagonists were used. It is thought that the neuroprotective mechanisms of action of mGluR5 antagonists involve limiting the increase in intracellular Са 2+ by reducing IP 3 and NMDA receptor activation. Huntington’s disease is related to a mutation in the HTT gene and the ability of the mutant huntingtin protein to sensitise IP 3 and NMDA receptors, thus triggering Са 2+ overload in the neurons. A neuroprotective effect in transgenic mice with Huntington’s disease was achieved by using positive allosteric modulators of mGluR5, capable of selectively activating cascades associated with the Homer protein and triggering Akt activation.

Homer2 and Homer3 modulate RANKL-induced NFATc1 signaling in osteoclastogenesis and bone metabolism.

The receptor activator of nuclear factor-kappa B ligand (RANKL) induces osteoclastogenesis by induction of Ca2+ oscillation, calcineurin activation and translocation into the nucleus of nuclear factor of activated T cells type c1 (NFATc1). Homer proteins are scaffold proteins. They regulate Ca2+ signaling by modulating the activity of multiple Ca2+ signaling proteins. Homers 2 and 3, but not Homer1, also independently affect the interaction between NFATc1 and calcineurin. However, to date, whether and how the Homers are involved in osteoclastogenesis remains unknown. In the present study, we investigated Homer2 and Homer3 roles in Ca2+ signaling and NFATc1 function during osteoclast differentiation. Deletion of Homer2/Homer3 (Homer2/3) markedly decreased the bone density of the tibia, resulting in bone erosion. RANKL-induced osteoclast differentiation is greatly facilitated in Homer2/3 DKO bone marrow-derived monocytes/macrophages (BMMs) due to increased NFATc1 expression and nuclear translocation. However, these findings did not alter RANKL-induced Ca2+ oscillations. Of note, RANKL treatment inhibited Homer proteins interaction with NFATc1, but it was restored by cyclosporine A treatment to inhibit calcineurin. Finally, RANKL treatment of Homer2/3 DKO BMMs significantly increased the formation of multinucleated cells. These findings suggest a novel potent mode of bone homeostasis regulation through osteoclasts differentiation. Specifically, we found that Homer2 and Homer3 regulate NFATc1 function through its interaction with calcineurin to regulate RANKL-induced osteoclastogenesis and bone metabolism.

Genetic disruption of the putative binding site for Homer on DmGluRA reduces sleep in Drosophila.

Homer proteins mediate plasticity and signaling at the postsynaptic density of neurons and are necessary for sleep and synaptic remodeling during sleep. The goal of this study was to investigate the mechanisms of sleep regulation by Homer signaling. Using the Drosophila animal model, we demonstrate that knockdown of Homer specifically in the brain reduces sleep and that Drosophila Homer binds to the sole Drosophila mGluR, known as DmGluRA. This is the first evidence that DmGluRA, which bears greatest homology to group II mammalian metabotropic glutamate receptors (mGluRs), shares functional homology with group I mGluRs which couple to Homer proteins in mammals. As sleep is associated with the physical dissociation of Homer and mGluRs proteins at the synapse, we sought to determine the functional necessity of Homer × DmGluRA interaction in sleep regulation. Using the CRISPR/Cas9 gene editing system, we generated a targeted amino acid replacement of the putative binding site for Homer on DmGluRA to prevent Homer and DmGluRA protein binding. We found that loss of the conserved proline-rich PPXXF sequence on DmGluRA reduces Homer/DmGluRA associations and significantly reduces sleep amount. Thus, we identify a conserved mechanism of synaptic plasticity in Drosophila and demonstrate that the interaction of Homer with DmGluRA is necessary to promote sleep.

Glutamatergic postsynaptic density in early life stress programming: Topographic gene expression of mGlu5 receptors and Homer proteins

Type-5 metabotropic glutamate receptors (mGlu5) have been implicated in the mechanism of resilience to stress. They form part of the postsynaptic density (PSD), a thickening of the glutamatergic synapse that acts as a multimodal hub for multiple cellular signaling. Perinatal stress in rats triggers alterations that make adult offspring less resilient to stress. In the present study, we examined the expression of gene encoding the mGlu5 (Grm5), as well as those encoding the short and long isoforms of Homer proteins in different brain regions of the offspring of dams exposed to repeated episodes of restraint stress during pregnancy (“perinatally stressed” or PRS offspring). To this end, we investigated unconditioned behavioral response using the light/dark box test, as well as the expression of PSD genes (Homer1a, Homer1b, and Grm5), in the medial prefrontal cortex, cortex, caudate-putamen, amygdala, and dorsal hippocampus. PRS rats spent significantly less time in the light area than the control group. In the amygdala, Homer1a mRNA levels were significantly increased in PRS rats, whereas Homer1b and Grm5 mRNA levels were reduced. In contrast, the transcript encoding for Homer1a was significantly reduced in the medial prefrontal cortex, caudate-putamen, and dorsal hippocampus of PRS rats. We also evaluated the relative ratio between Homer1a and Homer1b/Grm5 expression, finding a significant shift toward the expression of Homer1a in the amygdala and toward Homer1b/Grm5 in the other brain regions. These topographic patterns of Homer1a, Homer1b, and mGlu5 gene expression were significantly correlated with risk-taking behavior measured in the light/dark box test. Remarkably, in the amygdala and in other brain regions, Homer1b and Grm5 expression showed positive correlation with time spent in the light box, whereas Homer1a in the amygdala showed a negative correlation with risk-taking behavior, in contrast with all other brain regions analyzed, wherein these correlations were positive. These results suggest that perinatal stress programs the developmental expression of PSD molecules involved in mGlu5 signaling in discrete brain regions, with a predominant role for the amygdala.

Neurochondrin Antibody Serum Positivity in Three Cases of Autoimmune Cerebellar Ataxia

To report three cases of autoimmune ataxia patients with positive neurochondrin (NCDN) antibodies. Patients with unknown cerebellar ataxia were screened for autoimmune cerebellar ataxia (ACA)-related antibodies, including glutamic acid decarboxylase 65 (GAD65), delta/notch-like epidermal growth factor-related receptor (Tr/DNER), zinc finger protein 4 (ZIC4), inositol 1,4,5-triphosphate receptor 1 (ITPR1), Homer protein homologue 3 (Homer-3), neurochondrin (NCDN), Purkinje cell antibody 2 (PCA-2) and carbonic anhydrase-related protein VII (CARPVII). The antibodies were assessed by indirect immunofluorescence using transfected cells (cell-based assay, CBA) and monkey cerebellum (tissue-based assay, TBA) with the multi-antigen co-plate biochip mosaic technique. Patients with positive antibodies received immunotherapy and were followed up in the clinic. Clinical characteristics, laboratory data, and outcomes of antibody-positive patients were described, analysed and compared with previously reported cases. The NCDN antibody was positive in three male patients in whom the onset ages were four years and 11months, two years and seven months and 67years old. Serum antibody titres were 1:32, 1:100 and 1:320. Cerebral ataxia was the most prominent presentation. Cerebellar atrophy was found in one of the patients. Immunotherapy was effective in all three patients. The NCDN antibody is associated with autoimmune ataxia, and it has been suggested that the NCDN antibody should be tested in patients with cerebellar ataxia who are negative for routine ACA antibodies. Early immunotherapy may have a beneficial impact on prognosis.

Imaging tripartite synapses using super-resolution microscopy.

Astroglia are vital facilitators of brain development, homeostasis, and metabolic support. In addition, they are also essential to the formation and regulation of synaptic circuits. Due to the extraordinary complex, nanoscopic morphology of astrocytes, the underlying cellular mechanisms have been poorly understood. In particular, fine astrocytic processes that can be found in the vicinity of synapses have been difficult to study using traditional imaging techniques. Here, we describe a 3D three-colour super-resolution microscopy approach to unravel the nanostructure of tripartite synapses. The method is based on the SMLM technique direct stochastic optical reconstruction microscopy (dSTORM) which uses conventional fluorophore-labelled antibodies. This approach enables reconstructing the nanoscale localisation of individual astrocytic glutamate transporter (GLT-1) molecules surrounding presynaptic (bassoon) and postsynaptic (Homer1) protein localisations in fixed mouse brain sections. However, the technique is readily adaptable to other types of targets and tissues.

Biphasic Modulation of NMDA Receptor Function by Metabotropic Glutamate Receptors.

A recently reported rapid potentiation of NMDA receptors by Group I metabotropic glutamate receptors (mGluRIs) via a Homer protein link is distinct from the classical, relatively slow inhibitory G-protein-associated signaling triggered by mGluRI activation. The relationship between these two mechanisms remains unknown. Here, we focused on the mGluRI-dependent modulation of NMDAR response in hippocampal dentate gyrus granule cells and cerebellar granule cells of C57BL6-J mice and found that these two contrasting mechanisms overlap competitively on the time scale from hundreds of milliseconds to seconds, with the net effect depending on the cell type. At a shorter time interval (units of millisecond), the Homer-mediated signal from mGluRIs prevails, causing upregulation of NMDAR function, in both dentate gyrus granule cells and cerebellar granule cells. Our results shed light on the possible mechanisms of anti-schizophrenia drugs that disrupt Homer-containing protein link.SIGNIFICANCE STATEMENT Here we study modulation of NMDA receptors triggered by activation of metabotropic glutamate receptors Group I via two distinct pathways: classical G-protein signaling system and newly discovered high-speed modulatory mechanism associated with Homer-protein-containing direct molecular link. We found that these two contrasting mechanisms overlap competitively on the time scale from hundreds of milliseconds to seconds, with the net effect depending on the cell type. We have also found that both crosstalk mechanisms cause significant changes in synaptic strength and plasticity. Our results resolve an apparent discrepancy between earlier studies that demonstrated contradictive effects of Homer-containing protein link disruption on NMDA receptor signaling. On top of that, our data provide a plausible explanation for unclear action mechanisms of anti-schizophrenia drugs.

Targeting mGlu5 Metabotropic Glutamate Receptors in the Treatment of Cognitive Dysfunction in a Mouse Model of Phenylketonuria

We studied group-I metabotropic glutamate (mGlu) receptors in Pahenu2 (ENU2) mice, which mimic the genetics and neurobiology of human phenylketonuria (PKU), a metabolic disorder characterized, if untreated, by autism, and intellectual disability (ID). Male ENU2 mice showed increased mGlu5 receptor protein levels in the hippocampus and corpus striatum (but not in the prefrontal cortex) whereas the transcript of the mGlu5 receptor was unchanged. No changes in mGlu1 receptor mRNA and protein levels were found in any of the three brain regions of ENU2 mice. We extended the analysis to Homer proteins, which act as scaffolds by linking mGlu1 and mGlu5 receptors to effector proteins. Expression of the long isoforms of Homer was significantly reduced in the hippocampus of ENU2 mice, whereas levels of the short Homer isoform (Homer 1a) were unchanged. mGlu5 receptors were less associated to immunoprecipitated Homer in the hippocampus of ENU2 mice. The lack of mGlu5 receptor-mediated long-term depression (LTD) in wild-type mice (of BTBR strain) precluded the analysis of hippocampal synaptic plasticity in ENU2 mice. We therefore performed a behavioral analysis to examine whether pharmacological blockade of mGlu5 receptors could correct behavioral abnormalities in ENU2 mice. Using the same apparatus we sequentially assessed locomotor activity, object exploration, and spatial object recognition (spatial novelty test) after displacing some of the objects from their original position in the arena. Systemic treatment with the mGlu5 receptor antagonist, MPEP (20 mg/kg, i.p.), had a striking effect in the spatial novelty test by substantially increasing the time spent in exploring the displaced objects in ENU2 mice (but not in wild-type mice). These suggest a role for mGlu5 receptors in the pathophysiology of ID in PKU and suggest that, also in adult untreated animals, cognitive dysfunction may be improved by targeting these receptors with an appropriate therapy.

WW domain-binding protein 2 acts as an oncogene by modulating the activity of the glycolytic enzyme ENO1 in glioma

WW domain-binding protein 2 (WBP2) has been demonstrated as oncogenic in breast cancer. Many studies have revealed the WBP2 gene as a high-risk gene for leukoariaosis and cerebral white matter lesions is important in the pathologic stage of glioma development. This study aimed to illustrate the underlying mechanism by which WBP2 regulates the process of glioma development. The expression pattern of WBP2 in several tumor cells was determined, clarifying the carcinogenic action of WBP2 in glioma cells. Overexpression of WBP2 in glioma cells promoted cell proliferation and migration, and the number of S-phase cells, whereas the depletion of WBP2 by RNAi-mediated knockdown restrained cell growth and cell cycle progression. Upregulation of WBP2 significantly enhanced the tumorigenic ability of U251 cells in vivo. MS/GST pulldown assay identified α-enolase (ENO1) and Homer protein homolog 3 (Homer3) as novel potent interaction partners of WBP2. Knockdown of ENO1 or Homer3 allowed cell growth and migration to return to normal levels. Furthermore, in vitro and in vivo experiments indicated that the oncogenic role of WBP2 in glioma was through modulating ENO1 and glycolysis activity via the ENO1-PI3K/Akt signaling pathway. Collectively, these results reveal that WBP2 plays a vital role in the occurrence and development of glioma, indicating a target gene for glioblastoma treatment.

ИСПОЛЬЗОВАНИЕ ЗАЯКОРИВАЮЩИХ МОТИВОВ ДЛЯ ОБЕСПЕЧЕНИЯ ЦЕНТРАЛЬНОЙ ИЛИ ПЕРИФЕРИЧЕСКОЙ ЛОКАЛИЗАЦИИ ОПСИНОВ В ОПТОГЕНЕТИКЕ, "Российский физиологический журнал им. И.М. Сеченова"

One of the ways of optogenetic prosthetics of the degenerative retina is the approach aimed to the reconstruction of the ON/OFF receptive field of ganglionic neurons by targeting the exciting light-activated protein to the central part of the ganglion cell, and the inhibitory one to the periphery. Within the framework of this approach, we investigated the possibility of using various anchoring motifs to provide somatic or dendritic localization of opsins. It has been shown that the Kv2.1 potassium channel motif does not always provide exclusively central localization of the light-activated protein, which may be due to significant overexpression of the construct when strong ubiquitous promoters are used. In addition, we demonstrated the possibility of using one of the proteins that is part of the postsynaptic density, the Homer1 protein, as an anchoring motif for peripheral targeting of rhodopsin

Nacre extract prevents scopolamine-induced memory deficits in rodents

Objective: To investigate whether the extract from the nacreous layer of pearl oysters (nacre extract) improves impairments in memory caused by scopolamine administration in rodents. Methods: Nacre extract was prepared from the inner shell layer of pearl oyster. Effects of nacre extract on scopolamine-induced memory impairment were estimated using novel object recognition test, Y-maze test, and Barnes maze test. Effect of nacre extract on mRNA expressions which are genes associated with memory in the hippocampus was investigated using semi-quantitative reverse transcription polymerase chain reaction (RT-PCR) analysis. Results: Administration of nacre extract led to the protection against scopolamine-induced impairments in object recognition, short-term memory, and spatial memory. Treatment with nacre extract reversed the mRNA expression of brain-derived neurotrophic factor (BDNF) and Homer protein homolog 1 (Homer-la) in the hippocampus, which decreased with the treatment of scopolamine. Conclusions: These results suggest that nacre extract has attenuating effects on memory impairments induced by scopolamine through the increase in mRNA expression of BDNF and Homer-1a.

Perinatal Brain Docosahexaenoic Acid Concentration Has a Lasting Impact on Cognition in Mice

Background: Premature infants are deprived of prenatal accumulation of brain docosahexaenoic acid [DHA (22:6n-3)], an omega-3 fatty acid [ω-3 FA (n-3 FA)] important for proper development of cognitive function. The resulting brain DHA deficit can be reversed by ω-3 FA supplementation.Objective: The objective was to test whether there is a critical period for providing ω-3 FA to correct cognitive deficits caused by developmental ω-3 FA deprivation in mice.Methods: Twelve timed-pregnant mice [embryonic day 14 (E14), C57/BL6NCr] were fed an ω-3 FA-deficient diet containing 0.04% α-linolenic acid [ALA (18:3n-3)], and their offspring were fed the same deficient diet (Def group) or changed to an ω-3 FA-adequate diet containing 3.1% ALA at 3 wk, 2 mo, or 4 mo of age. In parallel, 3 E14 pregnant mice were fed the adequate diet and their offspring were fed the same diet (Adeq group) throughout the experiment. Brain FA composition, learning and memory, and hippocampal synaptic protein expression were evaluated at 6 mo by gas chromatography, the Morris water maze test, and western blot analysis, respectively.Results: Maternal dietary ω-3 FA deprivation decreased DHA by >50% in the brain of their offspring at 3 wk of age. The Def group showed significantly worse learning and memory at 6 mo than those groups fed the adequate diet. These pups also had decreased hippocampal expression of postsynaptic density protein 95 (43% of Adeq group), Homer protein homolog 1 (21% of Adeq group), and synaptosome-associated protein of 25 kDa (64% of Adeq group). Changing mice to the adequate diet at 3 wk, 2 mo, or 4 mo of age restored brain DHA to the age-matched adequate concentration. However, deficits in hippocampal synaptic protein expression and spatial learning and memory were normalized only when the diet was changed at 3 wk.Conclusion: Developmental deprivation of brain DHA by dietary ω-3 FA depletion in mice may have a lasting impact on cognitive function if not corrected at an early age.