Differentiating between Memory and Effector Cd8 T Cells by Altered Expression of Cell Surface O-Glycans

Currently there are few reliable cell surface markers that can clearly discriminate effector from memory T cells. To determine if there are changes in O-glycosylation between these two cell types, we analyzed virus-specific CD8 T cells at various time points after lymphocytic choriomeningitis virus infection of mice. Antigen-specific CD8 T cells were identified using major histocompatibility complex class I tetramers, and glycosylation changes were monitored with a monoclonal antibody (1B11) that recognizes O-glycans on mucin-type glycoproteins. We observed a striking upregulation of a specific cell surface O-glycan epitope on virus-specific CD8 T cells during the effector phase of the primary cytotoxic T lymphocyte (CTL) response. This upregulation showed a strong correlation with the acquisition of effector function and was downregulated on memory CD8 T cells. Upon reinfection, there was again increased expression of this specific O-glycan epitope on secondary CTL effectors, followed once more by decreased expression on memory cells. Thus, this study identifies a new cell surface marker to distinguish between effector and memory CD8 T cells. This marker can be used to isolate pure populations of effector CTLs and also to determine the proportion of memory CD8 T cells that are recruited into the secondary response upon reencounter with antigen. This latter information will be of value in optimizing immunization strategies for boosting CD8 T cell responses

Major Contribution of Somatostatin-Expressing Interneurons and Cannabinoid Receptors to Increased GABA Synaptic Activity in the Striatum of Huntington’s Disease Mice

Huntington’s disease (HD) is a heritable neurological disorder that affects cognitive and motor performance in patients carrying the mutated huntingtin (HTT) gene. In mouse models of HD, previous reports showed a significant increase in spontaneous GABAA receptor-mediated synaptic activity in striatal spiny projection neurons (SPNs). In this study, using optogenetics and slice electrophysiology, we examined the contribution of γ-aminobutyric acid (GABA)-ergic parvalbumin (PV)- and somatostatin (SOM)-expressing interneurons to the increase in GABA neurotransmission using the Q175 (heterozygote) mouse model of HD. Patch clamp recordings in voltage-clamp mode were performed on SPNs from brain slices of presymptomatic (2 months) and symptomatic (8 and 12 months) Q175 mice and wildtype (WT) littermates. While inhibitory postsynaptic currents (IPSCs) evoked in SPNs following optical activation of PV- and SOM-expressing interneurons differed in amplitude, no genotype-dependent differences were observed at all ages from both interneuron types; however, responses evoked by either type were found to have faster kinetics in symptomatic mice. Since SOM-expressing interneurons are constitutively active in striatal brain slices, we then examined the effects of acutely silencing these neurons in symptomatic mice with enhanced Natronomonas pharaonis halorhodopsin (eNpHR). Optically silencing SOM-expressing interneurons resulted in a greater decrease in the frequency of spontaneous IPSCs (sIPSCs) in a subset of SPNs from Q175 mice compared to WTs, suggesting that SOM-expressing interneurons are the main contributors to the overall increased GABA synaptic activity in HD SPNs. Additionally, the effects of activating GABAB and cannabinoid (CB1) receptors were investigated to determine whether these receptors were involved in modulating interneuron-specific GABA synaptic transmission and if this modulation differed in HD mice. When selectively activating PV- and SOM-expressing interneurons in the presence of the CB1 receptor agonist WIN-55,212, the magnitudes of the evoked IPSCs in SPNs decreased for both interneuron types although this change was less prominent in symptomatic Q175 SPNs during SOM-expressing interneuron activation. Overall, these findings show that dysfunction of SOM-expressing interneurons contributes to the increased GABA synaptic activity found in HD mouse models and that dysregulation of the endocannabinoid system may contribute to this effect

Loss of the thyroid hormone-binding protein Crym renders striatal neurons more vulnerable to mutant huntingtin in Huntington's disease

The mechanisms underlying preferential atrophy of the striatum in Huntington's disease (HD) are unknown. One hypothesis is that a set of gene products preferentially expressed in the striatum could determine the particular vulnerability of this brain region to mutant huntingtin (mHtt). Here, we studied the striatal protein µ-crystallin (Crym). Crym is the NADPH-dependent p38 cytosolic T3-binding protein (p38CTBP), a key regulator of thyroid hormone (TH) T3 (3,5,3′-triiodo-l-thyronine) transportation. It has been also recently identified as the enzyme that reduces the sulfur-containing cyclic ketimines, which are potential neurotransmitters. Here, we confirm the preferential expression of the Crym protein in the rodent and macaque striatum. Crym expression was found to be higher in the macaque caudate than in the putamen. Expression of Crym was reduced in the BACHD and Knock-in 140CAG mouse models of HD before onset of striatal atrophy. We show that overexpression of Crym in striatal medium-size spiny neurons using a lentiviral-based strategy in mice is neuroprotective against the neurotoxicity of an N-terminal fragment of mHtt in vivo. Thus, reduction of Crym expression in HD could render striatal neurons more susceptible to mHtt suggesting that Crym may be a key determinant of the vulnerability of the striatum. In addition our work points to Crym as a potential molecular link between striatal degeneration and the THs deregulation reported in HD patient

State of Reproductive Health In Women Veterans – VA Reproductive Health Diagnoses and Organization of Care

Reproductive health (RH) is a critical part of health. For women, RH encompasses gynecological health throughout life, preconception care, maternity care, cancer care, and the interaction of RH with other mental and medical conditions. Reproductive Health is defined as a state of complete physical, mental, and social well-be­ing and not merely the absence of reproductive disease or infirmity. This definition highlights the importance of taking a health systems approach that integrates RH care issues and services with other aspects of care needed across the life course. The RH needs of women are shaped by their stages of life and life experiences. For women Veterans, their military experiences may influence their RH in important ways. Given the increasing numbers of women in the military and women Veterans, it is critical to understand key aspects of RH in this unique population of women. This first report of the State of Reproductive Health in Women Veterans provides an overview of the RH diagnoses of women Veterans utilizing the Department of Veterans Affairs (VA) health care services, VA delivery of RH care, and a vision for RH in VA

Étude de l'implication potentielle des marqueurs du striatum dans la maladie de Huntington

Huntington's disease (HD) is an incurable inherited neurodegenerative disease. HD is caused by a mutation in the HD gene coding huntingtin (htt). This mutation leads to an expanded polyglutamine tract (polyQ) in the protein which is toxic to neurons. Although the htt is ubiquitously expressed in the central nervous system, the first area which degenerates is the striatum. A pattern of genes selectively expressed into the striatum may confer its vulnerability to mutated htt. We have studied the modifying effects of five newly identified striatal markers against the toxicity induced by mutated htt using lentiviral strategy in mice and histological approaches. For one of these markers, Double Cortin Kinase Like 3 (DCLK3), we have further determined their cellular localization and the potential mechanisms underlying their neuroprotector effects. The present work led to a better understanding of the function of the newly identified markers in the striatum and their potential roles in the preferential vulnerability of the striatum in HD.La maladie de Huntington (MH) est une maladie neurodégénérative héréditaire, incurable. Elle est due à une mutation dans le gène HD codant l'huntingtine (htt). Cette mutation se traduit dans la protéine par une augmentation de l'expansion polyglutamine (polyGln) qui la rend toxique. Bien que la htt soit ubiquitaire dans le système nerveux central, la dégénérescence touche préférentiellement le striatum. Un patron d'expression de gènes spécifiques du striatum pourrait expliquer cette vulnérabilité préférentielle. Nous avons étudié les effets "modificateurs" de 5 gènes préférentiellement exprimés dans le striatum vis-à-vis de la toxicité de la htt mutée par une approche lentivirale chez la souris. Nous avons caractérisé les effets de ces marqueurs striataux sur la toxicité induite par la htt mutée par différentes approches histologiques. Les "modificateurs" de la MH ont été étudiés plus en détail. Nous avons examiné leur localisation et les mécanismes sous-jacents à leurs effets neuroprotecteurs. Outre une meilleure compréhension du striatum, cette étude a permis la découverte de candidat neuroprotecteur qui pourrait permettre de développer de nouvelles thérapies

Abstract SFN 2013

Abstract SFN 2013International audienceHuntington's disease (HD), an inherited neurodegenerative disorder caused by a mutation in the IT15 gene, is characterized by massive degeneration of striatal medium-sized spiny neurons (MSNs) and loss of layers II, III and V cortical pyramidal neurons (CPNs). In both cases, interneurons are relatively spared of the degenerative process. Parvalbumin (PV)-expressing interneurons, also called fast-spiking interneurons (FSI), display fast-firing properties and mediate feed-forward inhibition in the striatum. They represent an abundant and homogenous population of GABAergic interneurons in the striatum. In contrast, cortical PV-interneurons are a heterogeneous population. They are mainly GABAergic large basket cells displaying FSI properties that project onto CPNs. We examined PV interneuron outputs in striatum and cortex in symptomatic R6/2 mice. We used adeno-associated virus type 2 to express channelrhodopsin-2 H134R (ChR2) in the striatum or in the sensorimotor cortex of one month old R6/2 and wildtype (WT) mice crossed with PV-CRE mice. The construct is only inserted in PV-positive cells by CRE recombination. The expression of these proteins was visualized by enhanced yellow fluorescent protein (EYFP) (ChR2-EYFP). Blue light (470 nm) was used to activate the EYFP-positive cells. Dorsolateral striatal MSNs and layer II/III CPNs were recorded in voltage clamp mode. Recordings from MSNs demonstrated that activation of PV-positive neurons induced significantly larger amplitude GABAergic responses in R6/2s compared to WTs in 60 day-old mice. R6/2 responses also displayed more rapid rise and decay times than those of WTs. There were no significant differences in responses from CPNs between WT and R6/2 mice. Interestingly, the ChR2-activated PV-positive cells induced higher GABAergic response amplitudes in CPNs than MSNs in a genotype-independent manner. Together, these data suggest that PV-expressing interneurons differentially affect MSNs in the striatum of R6/2 and WT mice but may not produce similar differential effects on CPNs. This could be explained by the fact that PV interneurons in the cortex are a more heterogeneous population than in the striatum or they are differentially affected in HD

Optogenetic control of parvalbumin-expressing interneurons in the R6/2 and Q175mouse models of Huntington’s disease

Abstract SFN 2014International audienceHuntington's disease (HD), a neurodegenerative disorder caused by a mutation in the IT15 gene, is characterized by dysfunction and ultimate degeneration of striatal medium-sized spiny neurons (MSNs) and cortical pyramidal neurons (CPNs). Although it was thought that interneurons were relatively spared in HD, recent studies have shown a significant loss of parvalbumin (PV)-expressing interneurons that increases with severity of the disease. PV-expressing interneurons display fast-firing properties and mediate feed-forward inhibition in the striatum as well as limit CPN excitability. MSNs display an increase in GABAergic activity whereas CPNs show an increase in glutamatergic activity in several HD mouse models as the phenotype progresses. We hypothesized that PV-expressing interneurons may contribute to MSN and CPN dysfunction in HD. Previously we demonstrated significant changes in PV-expressing interneuron-evoked inhibitory responses in MSNs in symptomatic R6/2 mice using optogenetics. Here, using a similar optogenetic paradigm, we further examined alterations in PV-expressing interneuron inputs to MSNs and to CPNs in the R6/2 model. Additionally, we examined PV-expressing interneuron evoked responses in another HD mouse model, the Q175 knock-in, which has a more protracted course of phenotype progression. R6/2 and Q175 mice were crossed with PV-Cre mice and subsequently injected with a Cre-dependent channelrhodopsin-2 (ChR2) construct using viral delivery. MSNs or layer II/III CPNs were recorded in slices in voltage clamp mode. In symptomatic R6/2 mice, MSN recordings showed that activation of striatal PV-expressing interneurons induced significantly larger evoked GABAergic responses with faster kinetics than responses from wildtype 4/6/202

Étude de l'implication potentielle des marqueurs du striatum dans la maladie de Huntington

Huntington's disease (HD) is an incurable inherited neurodegenerative disease. HD is caused by a mutation in the HD gene coding huntingtin (htt). This mutation leads to an expanded polyglutamine tract (polyQ) in the protein which is toxic to neurons. Although the htt is ubiquitously expressed in the central nervous system, the first area which degenerates is the striatum. A pattern of genes selectively expressed into the striatum may confer its vulnerability to mutated htt. We have studied the modifying effects of five newly identified striatal markers against the toxicity induced by mutated htt using lentiviral strategy in mice and histological approaches. For one of these markers, Double Cortin Kinase Like 3 (DCLK3), we have further determined their cellular localization and the potential mechanisms underlying their neuroprotector effects. The present work led to a better understanding of the function of the newly identified markers in the striatum and their potential roles in the preferential vulnerability of the striatum in HD.La maladie de Huntington (MH) est une maladie neurodégénérative héréditaire, incurable. Elle est due à une mutation dans le gène HD codant l'huntingtine (htt). Cette mutation se traduit dans la protéine par une augmentation de l'expansion polyglutamine (polyGln) qui la rend toxique. Bien que la htt soit ubiquitaire dans le système nerveux central, la dégénérescence touche préférentiellement le striatum. Un patron d'expression de gènes spécifiques du striatum pourrait expliquer cette vulnérabilité préférentielle. Nous avons étudié les effets "modificateurs" de 5 gènes préférentiellement exprimés dans le striatum vis-à-vis de la toxicité de la htt mutée par une approche lentivirale chez la souris. Nous avons caractérisé les effets de ces marqueurs striataux sur la toxicité induite par la htt mutée par différentes approches histologiques. Les "modificateurs" de la MH ont été étudiés plus en détail. Nous avons examiné leur localisation et les mécanismes sous-jacents à leurs effets neuroprotecteurs. Outre une meilleure compréhension du striatum, cette étude a permis la découverte de candidat neuroprotecteur qui pourrait permettre de développer de nouvelles thérapies

Study of potential involvement of striatal markers in Huntington's disease

La maladie de Huntington (MH) est une maladie neurodégénérative héréditaire, incurable.Elle est due à une mutation dans le gène HD codant l'huntingtine (htt). Cette mutation setraduit dans la protéine par une augmentation de l'expansion polyglutamine (polyGln) qui larend toxique. Bien que la htt soit ubiquitaire dans le système nerveux central, ladégénérescence touche préférentiellement le striatum. Un patron d'expression de gènesspécifiques du striatum pourrait expliquer cette vulnérabilité préférentielle. Nous avons étudiéles effets "modificateurs" de 5 gènes préférentiellement exprimés dans le striatum vis-à-visde la toxicité de la htt mutée par une approche lentivirale chez la souris. Nous avonscaractérisé les effets de ces marqueurs striataux sur la toxicité induite par la htt mutée pardifférentes approches histologiques. Les "modificateurs" de la MH ont été étudiés plus endétail. Nous avons examiné leur localisation et les mécanismes sous-jacents à leurs effetsneuroprotecteurs. Outre une meilleure compréhension du striatum, cette étude a permis ladécouverte de candidat neuroprotecteur qui pourrait permettre de développer de nouvellesthérapies.Huntington's disease (HD) is an incurable inherited neurodegenerative disease. HD iscaused by a mutation in the HD gene coding huntingtin (htt). This mutation leads to anexpanded polyglutamine tract (polyQ) in the protein which is toxic to neurons. Although thehtt is ubiquitously expressed in the central nervous system, the first area which degeneratesis the striatum. A pattern of genes selectively expressed into the striatum may confer itsvulnerability to mutated htt. We have studied the modifying effects of five newly identifiedstriatal markers against the toxicity induced by mutated htt using lentiviral strategy in miceand histological approaches. For one of these markers, Double Cortin Kinase Like 3(DCLK3), we have further determined their cellular localization and the potential mechanismsunderlying their neuroprotector effects. The present work led to a better understanding of thefunction of the newly identified markers in the striatum and their potential roles in thepreferential vulnerability of the striatum in HD

Abstract SFN 2013

Abstract SFN 2013International audienceHuntington's disease (HD), an inherited neurodegenerative disorder caused by a mutation in the IT15 gene, is characterized by massive degeneration of striatal medium-sized spiny neurons (MSNs) and loss of layers II, III and V cortical pyramidal neurons (CPNs). In both cases, interneurons are relatively spared of the degenerative process. Parvalbumin (PV)-expressing interneurons, also called fast-spiking interneurons (FSI), display fast-firing properties and mediate feed-forward inhibition in the striatum. They represent an abundant and homogenous population of GABAergic interneurons in the striatum. In contrast, cortical PV-interneurons are a heterogeneous population. They are mainly GABAergic large basket cells displaying FSI properties that project onto CPNs. We examined PV interneuron outputs in striatum and cortex in symptomatic R6/2 mice. We used adeno-associated virus type 2 to express channelrhodopsin-2 H134R (ChR2) in the striatum or in the sensorimotor cortex of one month old R6/2 and wildtype (WT) mice crossed with PV-CRE mice. The construct is only inserted in PV-positive cells by CRE recombination. The expression of these proteins was visualized by enhanced yellow fluorescent protein (EYFP) (ChR2-EYFP). Blue light (470 nm) was used to activate the EYFP-positive cells. Dorsolateral striatal MSNs and layer II/III CPNs were recorded in voltage clamp mode. Recordings from MSNs demonstrated that activation of PV-positive neurons induced significantly larger amplitude GABAergic responses in R6/2s compared to WTs in 60 day-old mice. R6/2 responses also displayed more rapid rise and decay times than those of WTs. There were no significant differences in responses from CPNs between WT and R6/2 mice. Interestingly, the ChR2-activated PV-positive cells induced higher GABAergic response amplitudes in CPNs than MSNs in a genotype-independent manner. Together, these data suggest that PV-expressing interneurons differentially affect MSNs in the striatum of R6/2 and WT mice but may not produce similar differential effects on CPNs. This could be explained by the fact that PV interneurons in the cortex are a more heterogeneous population than in the striatum or they are differentially affected in HD