Herpes Simplex Virus type-1 infection induces synaptic dysfunction in cultured cortical neurons via GSK-3 activation and intraneuronal amyloid-β protein accumulation

Increasing evidence suggests that recurrent Herpes Simplex Virus type 1 (HSV-1) infection spreading to the CNS is a risk factor for Alzheimer's Disease (AD) but the underlying mechanisms have not been fully elucidated yet. Here we demonstrate that in cultured mouse cortical neurons HSV-1 induced Ca 2+ -dependent activation of glycogen synthase kinase (GSK)-3. This event was critical for the HSV-1-dependent phosphorylation of amyloid precursor protein (APP) at Thr668 and the following intraneuronal accumulation of amyloid-β protein (Aβ). HSV-1-infected neurons also exhibited: i) significantly reduced expression of the presynaptic proteins synapsin-1 and synaptophysin; ii) depressed synaptic transmission. These effects depended on GSK-3 activation and intraneuronal accumulation of Aβ. In fact, either the selective GSK-3 inhibitor, SB216763, or a specific antibody recognizing Aβ (4G8) significantly counteracted the effects induced by HSV-1 at the synaptic level. Moreover, in neurons derived from APP KO mice and infected with HSV-1 Aβ accumulation was not found and synaptic protein expression was only slightly reduced when compared to wild-type infected neurons. These data further support our contention that HSV-1 infections spreading to the CNS may contribute to AD phenotype

Glutamate/GABA co-release selectively influences postsynaptic glutamate receptors in mouse cortical neurons.

Abstract Cultured rat cortical neurons co-expressing VGLUT1 and VGAT (mixed synapses) co-release Glu and GABA. Here, mixed synapses were studied in cultured mouse cortical neurons to verify whether in mice mixed synapses co-release Glu and GABA, and to gain insight into how they may influence excitation/inhibition balance. Results showed the existence of synapses and autapses that co-release Glu and GABA in cultured mouse cortical neurons, and the ability of both neurotransmitters to evoke postsynaptic responses mediated by ionotropic receptors. We studied the short-term plasticity of glutamatergic, GABAergic, and mixed responses and we found that the kinetics of mixPSC amplitude depression was similar to that observed in EPSCs, but it was different from that of IPSCs. We found similar presynaptic release characteristics in glutamatergic and mixed synapses. Analysis of postsynaptic features, obtained by measuring AMPAR- and NMDAR-mediated currents, showed that AMPAR-mediated currents were significantly higher in pure glutamatergic than in mixed synapses, whereas NMDAR-mediated currents were not significantly different from those measured in mixed synapses. Overall, our findings demonstrate that glutamatergic and mixed synapses share similar electrophysiological properties. However, co-release of GABA and Glu influences postsynaptic ionotropic glutamatergic receptor subtypes, thus selectively influencing AMPAR-mediated currents. These findings strengthen the view that mixed neurons can play a key role in CNS development and in maintaining the excitation-inhibition balance

Intracellular accumulation of tau oligomers in astrocytes and their synaptotoxic action rely on Amyloid Precursor Protein Intracellular Domain-dependent expression of Glypican-4

: Several studies including ours reported the detrimental effects of extracellular tau oligomers (ex-oTau) on glutamatergic synaptic transmission and plasticity. Astrocytes greatly internalize ex-oTau whose intracellular accumulation alters neuro/gliotransmitter handling thereby negatively affecting synaptic function. Both amyloid precursor protein (APP) and heparan sulfate proteoglycans (HSPGs) are required for oTau internalization in astrocytes but the molecular mechanisms underlying this phenomenon have not been clearly identified yet. Here we found that a specific antibody anti-glypican 4 (GPC4), a receptor belonging to the HSPG family, significantly reduced oTau uploading from astrocytes and prevented oTau-induced alterations of Ca2+-dependent gliotransmitter release. As such, anti-GPC4 spared neurons co-cultured with astrocytes from the astrocyte-mediated synaptotoxic action of ex-oTau, thus preserving synaptic vesicular release, synaptic protein expression and hippocampal LTP at CA3-CA1 synapses. Of note, the expression of GPC4 depended on APP and, in particular, on its C-terminal domain, AICD, that we found to bind Gpc4 promoter. Accordingly, GPC4 expression was significantly reduced in mice in which either APP was knocked-out or it contained the non-phosphorylatable amino acid alanine replacing threonine 688, thus becoming unable to produce AICD. Collectively, our data indicate that GPC4 expression is APP/AICD-dependent, it mediates oTau accumulation in astrocytes and the resulting synaptotoxic effects

Engineering memory with an extrinsically disordered kinase

: Synaptic plasticity plays a crucial role in memory formation by regulating the communication between neurons. Although actin polymerization has been linked to synaptic plasticity and dendritic spine stability, the causal link between actin polymerization and memory encoding has not been identified yet. It is not clear whether actin polymerization and structural changes in dendritic spines are a driver or a consequence of learning and memory. Using an extrinsically disordered form of the protein kinase LIMK1, which rapidly and precisely acts on ADF/cofilin, a direct modifier of actin, we induced long-term enlargement of dendritic spines and enhancement of synaptic transmission in the hippocampus on command. The activation of extrinsically disordered LIMK1 in vivo improved memory encoding and slowed cognitive decline in aged mice exhibiting reduced cofilin phosphorylation. The engineered memory by an extrinsically disordered LIMK1 supports a direct causal link between actin-mediated synaptic transmission and memory

Providing Reliable FIB Update Acknowledgments in SDN

Impairment of biliverdin reductase-A (BVR-A) is an early event leading to brain insulin resistance in AD. Intranasal insulin (INI) administration is under evaluation as a strategy to alleviate brain insulin resistance; however, the molecular mechanisms underlying INI beneficial effects are still unclear. We show that INI improves insulin signaling activation in the hippocampus and cortex of adult and aged 3×Tg-AD mice by ameliorating BVR-A activation. These changes were associated with a reduction of nitrosative stress, Tau phosphorylation, and Aβ oligomers in brain, along with improved cognitive functions. The role of BVR-A was strengthened by showing that cells lacking BVR-A: (i) develop insulin resistance if treated with insulin and (ii) can be recovered from insulin resistance only if treated with a BVR-A-mimetic peptide. These novel findings shed light on the mechanisms underlying INI treatment effects and suggest BVR-A as potential therapeutic target to prevent brain insulin resistance in AD

Polymorphisms of BoLA-DRB3 gene and its association with resistance / susceptibility to Leucosis in Holstein cattle from La Pampa

La leucosis bovina enzoótica es una enfermedad del ganado bovino adulto causada por el retrovirus de la leucemia bovina. Se puede manifestar como: una forma asintomática aleucémica, con un número normal de linfocitos B en sangre; una forma de linfocitosis permanente, con aumento del número de linfocitos B y como una presentación linfoproliferativa tumoral en forma de linfosarcoma. Los alelos de los genes del Complejo Principal de Histocompatibilidad Bovino (BoLA) han sido asociados con resistencia y susceptibilidad a enfermedades infecciosas. El objetivo general del presente estudio consistió en asociar los polimorfismos del exón 2 del gen BoLA-DRB3.2, definidos mediante la técnica de Reacción en Cadena de la Polimerasa y la técnica de Polimorfismos de la Longitud de los Fragmentos de Restricción (PCR-RFLP), con resistencia/susceptibilidad a leucosis en vacas Holstein de La Pampa. Se basó en un diseño caso/control, para lo cual se tomó muestra de sangre a 150 animales en 3 oportunidades con intervalos de tres meses cada una. Los animales fueron incluidos en el grupo caso cuando dieron positivos en la prueba de inmunodeficiencia en agar (DIDA) y cuyo recuento linfocitario en sangre fue ≥ 10.000 linfocitos/μl y el grupo control estuvo constituido con animales negativos en DIDA y que tenían < 10.000 linfocitos/μl de sangre. Los tests Exacto de Fisher y Odds Ratio (OR) de Woolf-Haldane se utilizaron para estudiar la asociación entre recuento de linfocitos y resultados del DIDA con las variantes alélicas. En 82 animales genotipados por PCRRFLP el alelo DRB3.2*22 evidenció un OR= 5,332 (p= 0,0138) y el alelo DRB3.2*11 mostró un OR= 0,11 (p=0,001) siendo más frecuentes en el grupo caso y en el grupo control, respectivamente. Estos resultados evidenciarían que vacas con el alelo DRB3.2*22 presentarían mayor riesgo a desarrollar leucosis y vacas con el alelo DRB3.2*11 un menor riesgo (resistencia). El análisis de la relación entre alelos del gen BoLA-DRB3.2 y resistencia/ susceptibilidad a leucosis podría mejorarse con investigaciones profundas en linajes familiares de vacas lecheras.EBL is a disease of adult cattle caused by the retrovirus, bovine leukemia. It can manifest: aleukemic an asymptomatic form, with a normal number of B lymphocytes in the blood; a form of permanent lymphocytosis, with an increase in the number of B lymphocytes and finally a lymphoproliferative tumor presentation in the form of lymphosarcoma. The alleles of the genes of the Bovine Major Histocompatibility Complex (BoLA) have been associated with resistance and susceptibility to infectious diseases. The overall objective of this study was to associate polymorphisms of the BoLA-DRB3.2 gene, defined by the technique of polymerase chain reaction technique and polymorphisms length of the restriction fragment (PCR-RFLP), with resistance / susceptibility to leucosis in Holstein cows of La Pampa. It relied on a case/control design, for which blood samples were taken to 150 animals in 3 opportunities with intervals of three months each. The case group comprised animals that were positive in the immunodiffusion agar animals test (DIDA) and whose blood lymphocyte count was ≥ 10.000 linf/μl and the control group included cows that ware negative for DIDA and present &lt; 10.000 linf/μl of blood. Fisher’s Exact test and Odds Ratio (OR) of Woolf-Haldane were used to study the association between lymphocyte count and DIDA results with allelic variants. In 82 animals genotyped by PCR-RFLP, the DRB3.2*22 allele showed an OR = 5.332 (p = 0.0138) and DRB3.2*11 allele had a OR value of 0.11 (p=0.001) and were the most frequent in the control group and in the case group, respectively. These results would showed DRB3.2*22 allele and DRB3.2*11 allele a high risk of having leucosis (susceptibility) and low risk to suffer (resistance) respectively. The analysis of the relationship between alleles of the BoLA and resistance/susceptibility to leucosis could be improved with deep research on family lineages of dairy cows.Instituto de Genética Veterinari

The nuclear pore protein Nup153 associates with chromatin and regulates cardiac gene expression in dystrophic mdx hearts.

Aims Beyond the control of nuclear-cytoplasmic trafficking nucleoporins regulate gene expression and are involved in cardiac diseases. Notably, a number of cardiovascular disorders have been linked to alterations in epigenetic mechanisms. Here we aimed to determine the contribution of Nup153 to the epigenetic alterations occurring in cardiomyopathy of dystrophin-deficient mdx mice (C57BL/10ScSn-Dmdmdx/J). Methods and results Nup153 was lysine-acetylated and its expression was significantly increased at protein level in mdx hearts compared with controls. Accordingly, lysine acetyl transferase (KAT) activity associated with Nup153 was higher in mdx hearts paralleling increased binding with the lysine acetylases P300/CBP-associated factor (PCAF) and p300. Interestingly, Nup153 silencing in mdx organotypic heart tissue slices caused a reduction in PCAF- and p300-specific activities. Remarkably, the level of nitric oxide (NO), which is reduced in mdx mice, was important for KAT-dependent regulation of Nup153. In fact, treatment of mdx heart tissue with an NO donor or the KAT inhibitor anacardic acid normalized Nup153 protein expression. Nup153 was recruited to chromatin and regulated the transcription of genes involved in cardiac remodelling, including the actin-binding protein nexilin. Accordingly, nexilin protein expression was abrogated by Nup153 silencing in mdx organotypic cultures. Electrophysiological and molecular experiments revealed that Nup153 overexpression in normal cardiomyocytes increases Cav1.2 calcium channel expression and function. Alterations in Nup153 protein expression and intracellular localization were also found in dystrophic cardiomyocytes derived from patient-specific induced pluripotent stem cells. Importantly, Nup153 up-regulation and increased acetylation were also found in the heart of Duchenne muscular dystrophy patients. Conclusions Our data indicate that Nup153 is an epigenetic regulator which, upon altered NO signalling, mediates the activation of genes potentially associated with early dystrophic cardiac remodelling

Anodal transcranial direct current stimulation boosts synaptic plasticity and memory in mice via epigenetic regulation of Bdnf expression

The effects of transcranial direct current stimulation (tDCS) on brain functions and the underlying molecular mechanisms are yet largely unknown. Here we report that mice subjected to 20-min anodal tDCS exhibited one-week lasting increases in hippocampal LTP, learning and memory. These effects were associated with enhanced: i) acetylation of brain-derived neurotrophic factor (Bdnf) promoter I; ii) expression of Bdnf exons I and IX; iii) Bdnf protein levels. The hippocampi of stimulated mice also exhibited enhanced CREB phosphorylation, pCREB binding to Bdnf promoter I and recruitment of CBP on the same regulatory sequence. Inhibition of acetylation and blockade of TrkB receptors hindered tDCS effects at molecular, electrophysiological and behavioral levels. Collectively, our findings suggest that anodal tDCS increases hippocampal LTP and memory via chromatin remodeling of Bdnf regulatory sequences leading to increased expression of this gene, and support the therapeutic potential of tDCS for brain diseases associated with impaired neuroplasticity

Interleukin 1β triggers synaptic and memory deficits in Herpes simplex virus type-1-infected mice by downregulating the expression of synaptic plasticity-related genes via the epigenetic MeCP2/HDAC4 complex

Extensive research provides evidence that neuroinflammation underlies numerous brain disorders. However, the molecular mechanisms by which inflammatory mediators determine synaptic and cognitive dysfunction occurring in neurodegenerative diseases (e.g., Alzheimer's disease) are far from being fully understood. Here we investigated the role of interleukin 1 beta (IL-1 beta), and the molecular cascade downstream the activation of its receptor, to the synaptic dysfunction occurring in the mouse model of multiple Herpes simplex virus type-1 (HSV-1) reactivations within the brain. These mice are characterized by neuroinflammation and memory deficits associated with a progressive accumulation of neurodegenerative hallmarks (e.g., amyloid-beta protein and tau hyperphosphorylation). Here we show that mice undergone two HSV-1 reactivations in the brain exhibited increased levels of IL-1 beta along with significant alterations of: (1) cognitive performances; (2) hippocampal long-term potentiation; (3) expression synaptic-related genes and pre- and post-synaptic proteins; (4) dendritic spine density and morphology. These effects correlated with activation of the epigenetic repressor MeCP2 that, in association with HDAC4, affected the expression of synaptic plasticity-related genes. Specifically, in response to HSV-1 infection, HDAC4 accumulated in the nucleus and promoted MeCP2 SUMOylation that is a post-translational modification critically affecting the repressive activity of MeCP2. The blockade of IL-1 receptors by the specific antagonist Anakinra prevented the MeCP2 increase and the consequent downregulation of gene expression along with rescuing structural and functional indices of neurodegeneration. Collectively, our findings provide novel mechanistic evidence on the role played by HSV-1-activated IL-1 beta signaling pathways in synaptic deficits leading to cognitive impairment

Basic and Preclinical Research for Personalized Medicine

Basic and preclinical research founded the progress of personalized medicine by providing a prodigious amount of integrated profiling data and by enabling the development of biomedical applications to be implemented in patient-centered care and cures. If the rapid development of genomics research boosted the birth of personalized medicine, further development in omics technologies has more recently improved our understanding of the functional genome and its relevance in profiling patients\u2019 phenotypes and disorders. Concurrently, the rapid biotechnological advancement in diverse research areas enabled uncovering disease mechanisms and prompted the design of innovative biological treatments tailored to individual patient genotypes and phenotypes. Research in stem cells enabled clarifying their role in tissue degeneration and disease pathogenesis while providing novel tools toward the development of personalized regenerative medicine strategies. Meanwhile, the evolving field of integrated omics technologies ensured translating structural genomics information into actionable knowledge to trace detailed patients\u2019 molecular signatures. Finally, neuroscience research provided invaluable models to identify preclinical stages of brain diseases. This review aims at discussing relevant milestones in the scientific progress of basic and preclinical research areas that have considerably contributed to the personalized medicine revolution by bridging the bench-to-bed gap, focusing on stem cells, omics technologies, and neuroscience fields as paradigms