Gt(ROSA)26Sor - gene trap ROSA 26, Philippe Soriano
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Publication
Journal: The Journal of neuroscience : the official journal of the Society for Neuroscience
November/12/2018
Abstract
For animals to survive, they must reliably predict during foraging which substances are suitable for consumption. Despite extensive study, the neural circuit mechanisms underlying such adaptive behavior remain poorly understood. Here, using a tastant (sucrose/quinine)-reinforced "go/no-go" task in male and female mice, we examined the anatomical and functional connectivity of the circuit linking the insular cortex (IC) to the central amygdala (CeA) and the role of this circuit in the establishment of appropriate behavioral responses. Using anatomic tracing approaches combined with optogenetics-assisted circuit mapping, we found that the gustatory region of the IC sends direct excitatory projections to the lateral division of the CeA (CeL), making monosynaptic excitatory connections with distinct populations of CeL neurons. Specific inhibition of neurotransmitter release from the CeL-projecting IC neurons prevented mice from acquiring the "no-go" response, and impaired the "go" responses in the go/no-go task. Furthermore, selective activation of the IC-CeL pathway with optogenetics drove unconditioned lick suppression in thirsty animals, induced aversive responses, and was sufficient to instruct conditioned action suppression in response to a cue predicting the optogenetic activation. These results indicate that activities in the IC-CeL circuit are critical for establishing taste-reinforced behavioral responses, including avoidance responses to an aversive tastant, and are sufficient to drive learning of anticipatory avoidance. Our findings suggest that the IC-CeL circuit plays an important role in guiding appropriate choices during foraging.SIGNIFICANCE STATEMENT An animal's ability to predict which substances are suitable for consumption and then produce an appropriate action to those substances is critical for survival. Here we found that activity in the circuit that links the insular cortex (IC) to the central amygdala (CeA) is necessary for establishing appropriate behavioral responses to taste-predicting cues. This neural circuit seems to be particularly tuned to avoid an unpleasant tastant, and is also sufficient to drive learning of such avoidance responses. These results suggest that the IC-CeA circuit is critical for generating appropriate behavioral responses during foraging when facing different choices.
Publication
Journal: The EMBO journal
December/6/2018
Abstract
In 1900, Adami speculated that a sequence of context-independent energetic and structural changes governed the reversion of differentiated cells to a proliferative, regenerative state. Accordingly, we show here that differentiated cells in diverse organs become proliferative via a shared program. Metaplasia-inducing injury caused both gastric chief and pancreatic acinar cells to decrease mTORC1 activity and massively upregulate lysosomes/autophagosomes; then increase damage associated metaplastic genes such as Sox9; and finally reactivate mTORC1 and re-enter the cell cycle. Blocking mTORC1 permitted autophagy and metaplastic gene induction but blocked cell cycle re-entry at S-phase. In kidney and liver regeneration and in human gastric metaplasia, mTORC1 also correlated with proliferation. In lysosome-defective Gnptab-/- mice, both metaplasia-associated gene expression changes and mTORC1-mediated proliferation were deficient in pancreas and stomach. Our findings indicate differentiated cells become proliferative using a sequential program with intervening checkpoints: (i) differentiated cell structure degradation; (ii) metaplasia- or progenitor-associated gene induction; (iii) cell cycle re-entry. We propose this program, which we term "paligenosis", is a fundamental process, like apoptosis, available to differentiated cells to fuel regeneration following injury.
Publication
Journal: Nature communications
November/27/2018
Abstract
The discovery of the first heart field (FHF) and the second heart field (SHF) led us to understand how cardiac lineages and structures arise during development. However, it remains unknown how they are specified. Here, we generate precardiac spheroids with pluripotent stem cells (PSCs) harboring GFP/RFP reporters under the control of FHF/SHF markers, respectively. GFP+ cells and RFP+ cells appear from two distinct areas and develop in a complementary fashion. Transcriptome analysis shows a high degree of similarities with embryonic FHF/SHF cells. Bmp and Wnt are among the most differentially regulated pathways, and gain- and loss-of-function studies reveal that Bmp specifies GFP+ cells and RFP+ cells via the Bmp/Smad pathway and Wnt signaling, respectively. FHF/SHF cells can be isolated without reporters by the surface protein Cxcr4. This study provides novel insights into understanding the specification of two cardiac origins, which can be leveraged for PSC-based modeling of heart field/chamber-specific disease.
Publication
Journal: The Journal of neuroscience : the official journal of the Society for Neuroscience
December/5/2018
Abstract
Homeostatic synaptic plasticity is a synaptic mechanism through which the nervous system adjusts synaptic excitation and inhibition to maintain network stability. Retinoic acid (RA) and its receptor RARα have been established as critical mediators of homeostatic synaptic plasticity. In vitro studies reveal that RA signaling enhances excitatory synaptic strength and decreases inhibitory synaptic strength. However, it is unclear whether RA-mediated homeostatic synaptic plasticity occurs in vivo, and if so, whether it operates at specific types of synapses. Here, we examine the impact of RA/RARα signaling in the monocular zone of primary visual cortex (V1m) in mice of either sex. Exogenous RA treatment in acute cortical slices resulted in a reduction in mIPSCs of layer 2/3 pyramidal neurons, an effect mimicked by visual deprivation induced by binocular enucleation in postcritical period animals. Postnatal deletion of RARα blocked RA's effect on mIPSCs. Cell type-specific deletion of RARα revealed that RA acted specifically on parvalbumin (PV)-expressing interneurons. RARα deletion in PV+ interneurons blocked visual deprivation-induced changes in mIPSCs, demonstrating the critical involvement of RA signaling in PV+ interneurons in vivo Moreover, visual deprivation- or RA-induced downregulation of synaptic inhibition was absent in the visual cortical circuit of constitutive and PV-specific Fmr1 KO mice, strongly suggesting a functional interaction between fragile X mental retardation protein and RA signaling pathways. Together, our results demonstrate that RA/RARα signaling acts as a key component for homeostatic regulation of synaptic transmission at the inhibitory synapses of the visual cortex.SIGNIFICANCE STATEMENT In vitro studies established that retinoic acid (RA) and its receptor RARα play key roles in homeostatic synaptic plasticity, a mechanism by which synaptic excitation/inhibition balance and network stability are maintained. However, whether synaptic RA signaling operates in vivo remains undetermined. Here, using a conditional RARα KO mouse and cell type-specific Cre-driver lines, we showed that RARα signaling in parvalbumin-expressing interneurons is crucial for visual deprivation-induced homeostatic synaptic plasticity at inhibitory synapses in visual cortical circuits. Importantly, this form of synaptic plasticity is absent when fragile X mental retardation protein is selectively deleted in parvalbumin-expressing interneurons, suggesting a functional connection between RARα and fragile X mental retardation protein signaling pathways in vivo Thus, dysfunction of RA-dependent homeostatic plasticity may contribute to cortical circuit abnormalities in fragile X syndrome.
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Publication
Journal: PLoS genetics
December/2/2018
Abstract
Successful embryo implantation requires a receptive endometrium. Poor uterine receptivity can account for implantation failure in women who experience recurrent pregnancy loss or multiple rounds of unsuccessful in vitro fertilization cycles. Here, we demonstrate that the transcription factor Forkhead Box O1 (FOXO1) is a critical regulator of endometrial receptivity in vivo. Uterine ablation of Foxo1 using the progesterone receptor Cre (PgrCre) mouse model resulted in infertility due to altered epithelial cell polarity and apoptosis, preventing the embryo from penetrating the luminal epithelium. Analysis of the uterine transcriptome after Foxo1 ablation identified alterations in gene expression for transcripts involved in the activation of cell invasion, molecular transport, apoptosis, β-catenin (CTNNB1) signaling pathway, and an increase in PGR signaling. The increase of PGR signaling was due to PGR expression being retained in the uterine epithelium during the window of receptivity. Constitutive expression of epithelial PGR during this receptive period inhibited expression of FOXO1 in the nucleus of the uterine epithelium. The reciprocal expression of PGR and FOXO1 was conserved in human endometrial samples during the proliferative and secretory phase. This demonstrates that expression of FOXO1 and the loss of PGR during the window of receptivity are interrelated and critical for embryo implantation.
Publication
Journal: Transgenic research
November/13/2018
Abstract
DNA site-specific recombination by Cre/loxP is a powerful tool for gene manipulation in experimental animals. VCre/VloxP and SCre/SloxP are novel site-specific recombination systems, consisting of a recombinase and its specific recognition sequences, which function in a manner similar to Cre/loxP. Previous reports using Escherichia coli and Oryzias latipes demonstrated the existence of stringent specificity between each recombinase and its target sites; VCre/VloxP, SCre/SloxP, and Cre/loxP have no cross-reactivity with each other. In this study, we established four novel knock-in (KI) mouse strains in which VloxP-EGFP, SloxP-tdTomato, CAG-VCre, and CAG-SCre genes were inserted into the ROSA26 locus. VloxP-EGFP and SloxP-tdTomato KI mice were reporter mice carrying EGFP or tdTomato genes posterior to the stop codon, which was floxed by VloxP or SloxP fragments, respectively. CAG-VCre and CAG-SCre KI mice carried VCre or SCre genes that were expressed ubiquitously. These two reporter mice were crossed with three different deleter mice, CAG-VCre KI, CAG-SCre KI, and Cre-expressing transgenic mice. Through these matings, we found that VCre/VloxP and SCre/SloxP systems were functional in mice similar to Cre/loxP, and that the recombinases showed tight specificity for their recognition sequences. Our results suggest that these novel recombination systems allow highly sophisticated genome manipulations and will be useful for tracing the fates of multiple cell lineages or elucidating complex spatiotemporal regulations of gene expression.
Publication
Journal: The Journal of neuroscience : the official journal of the Society for Neuroscience
November/13/2018
Abstract
In cortical structures, principal cell activity is tightly regulated by different GABAergic interneurons (INs). In particular, vasoactive intestinal polypeptide-expressing (VIP+) INs innervate preferentially other INs, providing a structural basis for temporal disinhibition of principal cells. However, relatively little is known about VIP+ INs in the amygdaloid basolateral complex (BLA). In this study, we report that VIP+ INs have a variable density in the distinct subdivisions of the mouse BLA. Based on different anatomical, neurochemical and electrophysiological criteria, VIP+ INs could be identified as interneuron-selective INs and basket cells expressing CB1 cannabinoid receptors. Whole-cell recordings of VIP+ interneuron-selective INs revealed 3 different spiking patterns, which did not associate with the expression of calretinin. Genetic targeting combined with optogenetics and in vitro recordings allowed us to identify several types of BLA INs innervated by VIP+ INs, including other interneuron-selective INs, basket and neurogliaform cells. Moreover, light stimulation of VIP+ basket cell axon terminals, characterized by CB1 sensitivity, evoked IPSPs in ∼20% of principal neurons. Finally, we show that VIP+ INs receive a dense innervation from both GABAergic, although only 10% from other VIP+ INs, and distinct glutamatergic inputs, identified by their expression of different vesicular glutamate transporters.In conclusion, our study provides a wide-range analysis of single-cell properties of VIP+ INs in the mouse BLA and of their intrinsic and extrinsic connectivity. Our results reinforce the knowledge that VIP+ INs are structurally and functionally heterogeneous and that this heterogeneity could mediate different roles in amygdala-dependent functions.Significance statement:We provide the first comprehensive analysis of the distribution of VIP+ interneurons across the entire mouse BLA, as well as of their morphological and physiological properties. VIP+ interneurons in the neocortex preferentially target other interneurons to form a disinhibitory network that facilitates principal cell firing. Our study is the first to demonstrate the presence of such a disinhibitory circuitry in the BLA. We observed structural and functional heterogeneity of these INs and characterized their input/output connectivity. We also identified several types of BLA interneurons postsynaptic to VIP+ INs, whose inhibition may provide a temporal window for principal cell firing and facilitate associative plasticity, e.g. in fear learning. Disinhibition, thus, is emerging as a general mechanism, not limited to the neocortex.
Publication
Journal: Frontiers in cellular neuroscience
November/13/2018
Abstract
Previous studies have shown that parvalbumin-expressing neurons (CC-Parv neurons) connect the two hemispheres of motor and sensory areas via the corpus callosum, and are a functional part of the cortical circuit. Here we test the hypothesis that layer 5 CC-Parv neurons possess anatomical and molecular mechanisms which dampen excitability and modulate the gating of interhemispheric inhibition. In order to investigate this hypothesis we use viral tracing to determine the anatomical and electrophysiological properties of layer 5 CC-Parv and parvalbumin-expressing (Parv) neurons of the mouse auditory cortex (AC). Here we show that layer 5 CC-Parv neurons had larger dendritic fields characterized by longer dendrites that branched farther from the soma, whereas layer 5 Parv neurons had smaller dendritic fields characterized by shorter dendrites that branched nearer to the soma. The layer 5 CC-Parv neurons are characterized by delayed action potential (AP) responses to threshold currents, lower firing rates, and lower instantaneous frequencies compared to the layer 5 Parv neurons. Kv1.1 containing K+ channels are the main source of the AP repolarization of the layer 5 CC-Parv and have a major role in determining both the spike delayed response, firing rate and instantaneous frequency of these neurons.
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Publication
Journal: eLife
November/13/2018
Abstract
Delineating the basic cellular components of cortical inhibitory circuits remains a fundamental issue in order to understand their specific contributions to microcircuit function. It is still unclear how current classifications of cortical interneuron subtypes relate to biological processes such as their developmental specification. Here we identified the developmental trajectory of neurogliaform cells (NGCs), the main effectors of a powerful inhibitory motif recruited by long-range connections. Using in vivo genetic lineage-tracing in mice, we report that NGCs originate from a specific pool of 5-HT3AR-expressing Hmx3+ cells located in the preoptic area (POA). Hmx3-derived 5-HT3AR+ cortical interneurons (INs) expressed the transcription factors PROX1, NR2F2, the marker reelin but not VIP and exhibited the molecular, morphological and electrophysiological profile of NGCs. Overall, these results indicate that NGCs are a distinct class of INs with a unique developmental trajectory and open the possibility to study their specific functional contribution to cortical inhibitory microcircuit motifs.
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Publication
Journal: Neuron
November/13/2018
Abstract
Cholinergic interneurons (ChIs) of the striatum pause their firing in response to salient stimuli and conditioned stimuli after learning. Several different mechanisms for pause generation have been proposed, but a unifying basis has not previously emerged. Here, using in vivo and ex vivo recordings in rat and mouse brain and a computational model, we show that ChI pauses are driven by withdrawal of excitatory inputs to striatum and result from a delayed rectifier potassium current (IKr) in concert with local neuromodulation. The IKr is sensitive to Kv7.2/7.3 blocker XE-991 and enables ChIs to report changes in input, to pause on excitatory input recession, and to scale pauses with input strength, in keeping with pause acquisition during learning. We also show that although dopamine can hyperpolarize ChIs directly, its augmentation of pauses is best explained by strengthening excitatory inputs. These findings provide a basis to understand pause generation in striatal ChIs. VIDEO ABSTRACT.
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Publication
Journal: Frontiers in neuroscience
November/13/2018
Abstract
Sleep/wake behavior is regulated by distinct groups of neurons, such as dopaminergic, noradrenergic, and orexinergic neurons. Although monoaminergic neurons are usually considered to be wake-promoting, the role of serotonergic neurons in sleep/wake behavior remains inconclusive because of the effect of serotonin (5-HT)-deficiency on brain development and the compensation for inborn 5-HT deficiency by other sleep/wake-regulating neurons. Here, we performed selective ablation of central 5-HT neurons in the newly developed Rosa-diphtheria toxin receptor (DTR)-tdTomato mouse line that was crossed with Pet1Cre/+ mice to examine the role of 5-HT neurons in the sleep/wake behavior of adult mice. Intracerebroventricular administration of diphtheria toxin completely ablated tdTomato-positive cells in Pet1Cre/+; Rosa-DTR-tdTomato mice. Electroencephalogram/electromyogram-based sleep/wake analysis demonstrated that central 5-HT neuron ablation in adult mice decreased the time spent in rapid eye movement (REM) sleep, which was associated with fewer transitions from non-REM (NREM) sleep to REM sleep than in control mice. Central 5-HT neuron-ablated mice showed attenuated wake response to a novel environment and increased theta power during wakefulness compared to control mice. The current findings indicated that adult 5-HT neurons work to support wakefulness and regulate REM sleep time through a biased transition from NREM sleep to REM sleep.
Publication
Journal: Endocrinology
June/10/2015
Abstract
Peptides derived from the proopiomelanocortin (POMC) precursor are critical for the normal regulation of many physiological parameters, and POMC deficiency results in severe obesity and metabolic dysfunction. Conversely, augmentation of central nervous system melanocortin function is a promising therapeutic avenue for obesity and diabetes but is confounded by detrimental cardiovascular effects including hypertension. Because the hypothalamic population of POMC-expressing neurons is neurochemically and neuroanatomically heterogeneous, there is interest in the possible dissociation of functionally distinct POMC neuron subpopulations. We used a Cre recombinase-dependent and hypothalamus-specific reactivatable PomcNEO allele to restrict Pomc expression to hypothalamic neurons expressing leptin receptor (Lepr) in mice. In contrast to mice with total hypothalamic Pomc deficiency, which are severely obese, mice with Lepr-restricted Pomc expression displayed fully normal body weight, food consumption, glucose homeostasis, and locomotor activity. Thus, Lepr+ POMC neurons, which constitute approximately two-thirds of the total POMC neuron population, are sufficient for normal regulation of these parameters. This functional dissociation approach represents a promising avenue for isolating therapeutically relevant POMC neuron subpopulations.
Publication
Journal: Neuron
September/12/2001
Abstract
Mice that lack all beta1-class integrins in neurons and glia die prematurely after birth with severe brain malformations. Cortical hemispheres and cerebellar folia fuse, and cortical laminae are perturbed. These defects result from disorganization of the cortical marginal zone, where beta1-class integrins regulate glial endfeet anchorage, meningeal basement membrane remodeling, and formation of the Cajal-Retzius cell layer. Surprisingly, beta1-class integrins are not essential for neuron-glia interactions and neuronal migration during corticogenesis. The phenotype of the beta1-deficient mice resembles pathological changes observed in human cortical dysplasias, suggesting that defective integrin-mediated signal transduction contributes to the development of some of these diseases.
Publication
Journal: Proceedings of the National Academy of Sciences of the United States of America
October/17/2011
Abstract
In mammals, endogenous siRNAs (endo-siRNAs) have only been reported in murine oocytes and embryonic stem cells. Here, we show that murine spermatogenic cells express numerous endo-siRNAs, which are likely to be derived from naturally occurring double-stranded RNA (dsRNA) precursors. The biogenesis of these testicular endo-siRNAs is DROSHA independent, but DICER dependent. These male germ cell endo-siRNAs can potentially target hundreds of transcripts or thousands of DNA regions in the genome. Overall, our work has unveiled another hidden layer of regulation imposed by small noncoding RNAs during male germ cell development.
Publication
Journal: Molecular and cellular neurosciences
November/20/2018
Abstract
The main olfactory epithelium (MOE) of an adult mouse harbors a few million mature olfactory sensory neurons (OSNs), which are traditionally defined as mature by their expression of the olfactory marker protein (OMP). Mature OSNs differentiate in situ from stem cells at the base of the MOE. The consensus view is that mature OSNs have a defined lifespan and then undergo programmed cell death, and that the adult MOE maintains homeostasis by generating new mature OSNs from stem cells. But there is also evidence for mature OSNs that are long-lived. Thus far modern genetic tools have not been applied to quantify survival of a population of OSNs that are mature at a given point in time. Here, a genetic strategy was developed to label irreversibly OMP-expressing OSNs in mice. A gene-targeted OMP-CreERT2 strain was generated in which mature OSNs express an enzymatically inactive version of the Cre recombinase. The fusion protein CreERT2 becomes transiently active when exposed to tamoxifen, and in the presence of a Cre reporter in the genome such as tdRFP, CreERT2-expressing cells become irreversibly labeled. A cohort of mice was generated with the same day of birth by in vitro fertilization and embryo transfer, and injected tamoxifen in their mothers at E18.5 of gestation. I counted RFP immunoreactive cells in the MOE and vomeronasal organ of 36 tamoxifen-exposed OMP-CreERT2 × tdRFP mice from 7 age groups: postnatal day (PD)1.5, PD3.5, PD6.5, 3 weeks, 9 weeks, 6 months, and 12 months. Approximately 7.8% of perinatally labeled cells remain at 12 months, confirming that some mature OSNs are indeed long-lived. The survival curve of the population of perinatally labeled MOE cells can be modeled with a mean half-life of 26 days for the population as a whole, excluding the long-lived cells.
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Publication
Journal: Cell stem cell
November/19/2018
Abstract
Radial glia (RG) are embryonic neural stem cells (NSCs) that produce neuroblasts and provide fibers that act as a scaffold for neuroblast migration during embryonic development. Although they normally disappear soon after birth, here we found that RG fibers can persist in injured neonatal mouse brains and act as a scaffold for postnatal ventricular-subventricular zone (V-SVZ)-derived neuroblasts that migrate to the lesion site. This injury-induced maintenance of RG fibers has a limited time window during post-natal development and promotes directional saltatory movement of neuroblasts via N-cadherin-mediated cell-cell contacts that promote RhoA activation. Transplanting an N-cadherin-containing scaffold into injured neonatal brains likewise promotes migration and maturation of V-SVZ-derived neuroblasts, leading to functional improvements in impaired gait behaviors. Together these results suggest that RG fibers enable postnatal V-SVZ-derived neuroblasts to migrate toward sites of injury, thereby enhancing neuronal regeneration and functional recovery from neonatal brain injuries.
Publication
Journal: PLoS genetics
December/3/2018
Abstract
Plasmacytoid and conventional dendritic cells (pDCs and cDCs) arise from monocyte and dendritic progenitors (MDPs) and common dendritic progenitors (CDPs) through gene expression changes that remain partially understood. Here we show that the Ikaros transcription factor is required for DC development at multiple stages. Ikaros cooperates with Notch pathway activation to maintain the homeostasis of MDPs and CDPs. Ikaros then antagonizes TGFβ function to promote pDC differentiation from CDPs. Strikingly, Ikaros-deficient CDPs and pDCs express a cDC-like transcriptional signature that is correlated with TGFβ activation, suggesting that Ikaros is an upstream negative regulator of the TGFβ pathway and a repressor of cDC-lineage genes in pDCs. Almost all of these phenotypes can be rescued by short-term in vitro treatment with γ-secretase inhibitors, which affects both TGFβ-dependent and -independent pathways, but is Notch-independent. We conclude that Ikaros is a crucial differentiation factor in early dendritic progenitors that is required for pDC identity.
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Publication
Journal: PLoS genetics
December/3/2018
Abstract
Left ventricular non-compaction (LVNC) is a rare cardiomyopathy associated with a hypertrabeculated phenotype and a large spectrum of symptoms. It is still unclear whether LVNC results from a defect of ventricular trabeculae development and the mechanistic basis that underlies the varying severity of this pathology is unknown. To investigate these issues, we inactivated the cardiac transcription factor Nkx2-5 in trabecular myocardium at different stages of trabecular morphogenesis using an inducible Cx40-creERT2 allele. Conditional deletion of Nkx2-5 at embryonic stages, during trabecular formation, provokes a severe hypertrabeculated phenotype associated with subendocardial fibrosis and Purkinje fiber hypoplasia. A milder phenotype was observed after Nkx2-5 deletion at fetal stages, during trabecular compaction. A longitudinal study of cardiac function in adult Nkx2-5 conditional mutant mice demonstrates that excessive trabeculation is associated with complex ventricular conduction defects, progressively leading to strain defects, and, in 50% of mutant mice, to heart failure. Progressive impaired cardiac function correlates with conduction and strain defects independently of the degree of hypertrabeculation. Transcriptomic analysis of molecular pathways reflects myocardial remodeling with a larger number of differentially expressed genes in the severe versus mild phenotype and identifies Six1 as being upregulated in hypertrabeculated hearts. Our results provide insights into the etiology of LVNC and link its pathogenicity with compromised trabecular development including compaction defects and ventricular conduction system hypoplasia.
Publication
Journal: Journal of neurochemistry
November/25/2018
Abstract
Visual information is detected by the retina and transmitted into the brain by retinal ganglion cells. In rodents, the visual thalamus is a major recipient of retinal ganglion cells axons and is divided into three functionally distinct nuclei: the dorsal lateral geniculate nucleus (dLGN), ventral LGN (vLGN), and intergeniculate leaflet. Despite being densely innervated by retinal input, each nucleus in rodent visual thalamus possesses diverse molecular profiles which underpin their unique circuitry and cytoarchitecture. Here, we combined large-scale unbiased proteomic and transcriptomic analyses to elucidate the molecular expression profiles of the developing mouse dLGN and vLGN. We identified several extracellular matrix proteins as differentially expressed in these regions, particularly constituent molecules of perineuronal nets (PNNs). Remarkably, we discovered at least two types of molecularly distinct Aggrecan-rich PNN populations in vLGN, exhibiting non-overlapping spatial, temporal, and cell-type specific expression patterns. The mechanisms responsible for the formation of these two populations of PNNs also differ as the formation of Cat315+ PNNs (but not WFA+ PNNs) required input from the retina. This study is first to suggest that cell type- and molecularly specific supramolecular assemblies of extracellular matrix may play important roles in the circuitry associated with the subcortical visual system and in the processing of visual information. Open Data: Materials are available on https://cos.io/our-services/open-science-badges/ https://osf.io/93n6m/.
Publication
Journal: American journal of physiology. Lung cellular and molecular physiology
November/29/2018
Abstract
Supplemental oxygen given to preterm infants has been associated with permanently altering postnatal lung development. Now that these individuals are reaching adulthood, there is growing concern that early life oxygen exposure may also promote cardiovascular disease through poorly understood mechanisms. We previously reported that adult mice exposed to 100% oxygen between postnatal days 0 and 4 develop pulmonary hypertension, defined pathologically by capillary rarefaction, dilation of arterioles and veins, cardiac failure, and a reduced lifespan. Here, Affymetrix Gene Arrays are used to identify early transcriptional changes that take place in the lung before pulmonary capillary rarefaction. We discovered neonatal hyperoxia reduced expression of cardiac muscle genes, including those involved in contraction, calcium signaling, mitochondrial respiration, and vasodilation. Quantitative RT-PCR, immunohistochemistry, and genetic lineage mapping using Myh6CreER; Rosa26RmT/mG mice revealed this reflected loss of pulmonary vein cardiomyocytes. The greatest loss of cadiomyocytes was seen within the lung followed by a graded loss beginning at the hilum and extending into the left atrium. Loss of these cells was seen by 2 wk of age in mice exposed to ≥80% oxygen and was attributed, in part, to reduced proliferation. Administering mitoTEMPO, a scavenger of mitochondrial superoxide during neonatal hyperoxia prevented loss of these cells. Since pulmonary vein cardiomyocytes help pump oxygen-rich blood out of the lung, their early loss following neonatal hyperoxia may contribute to cardiovascular disease seen in these mice, and perhaps in people who were born preterm.
Publication
Journal: Cancer research
November/29/2018
Abstract
New targets are required for treating prostate cancer, particularly castrate-resistant disease. Previous studies reported that calcium/calmodulin-dependent protein kinase kinase 2 (CAMKK2) expression is increased in human prostate cancer. Here, we show that Camkk2 deletion or pharmacologic inhibition protects against prostate cancer development in a preclinical mouse model that lacks expression of prostate-specific Pten. In contrast, deletion of AMP-activated protein kinase (Ampk) β1 resulted in earlier onset of adenocarcinoma development. These findings suggest for the first time that Camkk2 and Ampk have opposing effects in prostate cancer progression. Loss of CAMKK2 in vivo or in human prostate cancer cells reduced the expression of two key lipogenic enzymes, acetyl-CoA carboxylase and fatty acid synthase. This reduction was mediated via a posttranscriptional mechanism, potentially involving a decrease in protein translation. Moreover, either deletion of CAMKK2 or activation of AMPK reduced cell growth in human prostate cancer cells by inhibiting de novo lipogenesis. Activation of AMPK in a panel of human prostate cancer cells inhibited cell proliferation, migration, and invasion as well as androgen-receptor signaling. These findings demonstrate that CAMKK2 and AMPK have opposing effects on lipogenesis, providing a potential mechanism for their contrasting effects on prostate cancer progression in vivo They also suggest that inhibition of CAMKK2 combined with activation of AMPK would offer an efficacious therapeutic strategy in treatment of prostate cancer.Significance: These findings show that CAMKK2 and its downstream target AMPK have opposing effects on prostate cancer development and raise the possibility of a new combined therapeutic approach that inhibits CAMKK2 and activates AMPK. Cancer Res; 78(24); 1-15. ©2018 AACR.
Publication
Journal: Circulation research
June/7/2018
Abstract
BACKGROUND
COMMD (copper metabolism MURR1 domain)-containing proteins are a part of the CCC (COMMD-CCDC22 [coiled-coil domain containing 22]-CCDC93 [coiled-coil domain containing 93]) complex facilitating endosomal trafficking of cell surface receptors. Hepatic COMMD1 inactivation decreases CCDC22 and CCDC93 protein levels, impairs the recycling of the LDLR (low-density lipoprotein receptor), and increases plasma low-density lipoprotein cholesterol levels in mice. However, whether any of the other COMMD members function similarly as COMMD1 and whether perturbation in the CCC complex promotes atherogenesis remain unclear.
OBJECTIVE
The main aim of this study is to unravel the contribution of evolutionarily conserved COMMD proteins to plasma lipoprotein levels and atherogenesis.
RESULTS
Using liver-specific Commd1, Commd6, or Commd9 knockout mice, we investigated the relation between the COMMD proteins in the regulation of plasma cholesterol levels. Combining biochemical and quantitative targeted proteomic approaches, we found that hepatic COMMD1, COMMD6, or COMMD9 deficiency resulted in massive reduction in the protein levels of all 10 COMMDs. This decrease in COMMD protein levels coincided with destabilizing of the core (CCDC22, CCDC93, and chromosome 16 open reading frame 62 [C16orf62]) of the CCC complex, reduced cell surface levels of LDLR and LRP1 (LDLR-related protein 1), followed by increased plasma low-density lipoprotein cholesterol levels. To assess the direct contribution of the CCC core in the regulation of plasma cholesterol levels, Ccdc22 was deleted in mouse livers via CRISPR/Cas9-mediated somatic gene editing. CCDC22 deficiency also destabilized the complete CCC complex and resulted in elevated plasma low-density lipoprotein cholesterol levels. Finally, we found that hepatic disruption of the CCC complex exacerbates dyslipidemia and atherosclerosis in ApoE3*Leiden mice.
CONCLUSIONS
Collectively, these findings demonstrate a strong interrelationship between COMMD proteins and the core of the CCC complex in endosomal LDLR trafficking. Hepatic disruption of either of these CCC components causes hypercholesterolemia and exacerbates atherosclerosis. Our results indicate that not only COMMD1 but all other COMMDs and CCC components may be potential targets for modulating plasma lipid levels in humans.
Publication
Journal: Circulation research
June/15/2011
Abstract
BACKGROUND
The basic helix-loop-helix (bHLH) transcription factors Hand1 and Hand2 are essential for embryonic development. Given their requirement for cardiogenesis, it is imperative to determine their impact on cardiovascular function.
OBJECTIVE
To deduce the role of Hand2 within the epicardium.
RESULTS
We engineered a Hand1 allele expressing Cre recombinase. Cardiac Hand1 expression is largely limited to cells of the primary heart field, overlapping little with Hand2 expression. Hand1 is expressed within the septum transversum, and the Hand1 lineage marks the proepicardial organ and epicardium. To examine Hand factor functional overlap, we conditionally deleted Hand2 from Hand1-expressing cells. Hand2 mutants display defective epicardialization and fail to form coronary arteries, coincident with altered extracellular matrix deposition and Pdgfr expression.
CONCLUSIONS
These data demonstrate a hierarchal relationship whereby transient Hand1 septum transversum expression defines epicardial precursors that are subsequently dependent on Hand2 function.
Publication
Journal: Immunity
January/28/2009
Abstract
Dendritic cells are critically involved in the promotion and regulation of T cell responses. Here, we report a mouse strain that lacks conventional CD11c(hi) dendritic cells (cDCs) because of constitutive cell-type specific expression of a suicide gene. As expected, cDC-less mice failed to mount effective T cell responses resulting in impaired viral clearance. In contrast, neither thymic negative selection nor T regulatory cell generation or T cell homeostasis were markedly affected. Unexpectedly, cDC-less mice developed a progressive myeloproliferative disorder characterized by prominent extramedullary hematopoiesis and increased serum amounts of the cytokine Flt3 ligand. Our data identify a critical role of cDCs in the control of steady-state hematopoiesis, revealing a feedback loop that links peripheral cDCs to myelogenesis through soluble growth factors, such as Flt3 ligand.
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