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Genes encoding cell-surface proteins control nervous system development and are implicated in neurological disorders. These genes produce alternative mRNA isoforms which remain poorly characterized, impeding understanding of how disease-associated mutations cause pathology. Here we introduce a strategy to define complete portfolios of full-length isoforms encoded by individual genes. Applying this approach to neural cell-surface molecules, we identify thousands of unannotated isoforms expressed in retina and brain. By mass spectrometry we confirm expression of newly-discovered proteins on the cell surface in vivo. Remarkably, we discover that the major isoform of a retinal degeneration gene, CRB1, was previously overlooked. This CRB1 isoform is the only one expressed by photoreceptors, the affected cells in CRB1 disease. Using mouse mutants, we identify a function for this isoform at photoreceptor-glial junctions and demonstrate that loss of this isoform accelerates photoreceptor death. Therefore, our isoform identification strategy enables discovery of new gene functions relevant to disease., Here the authors present an approach that can reveal the full complement of mRNA isoforms encoded by individual genes, and they identify a major isoform of the retinal degeneration gene CRB1 which functions at the cell-cell junctions of the outer limiting membrane to promote photoreceptor survival.

In microscopy-based drug screens, fluorescent markers carry critical information on how compounds affect different biological processes. However, practical considerations, such as the labor and preparation formats needed to produce different image channels, hinders the use of certain fluorescent markers. Consequently, completed screens may lack biologically informative but experimentally impractical markers. Here, we present a deep learning method for overcoming these limitations. We accurately generated predicted fluorescent signals from other related markers and validated this new machine learning (ML) method on two biologically distinct datasets. We used the ML method to improve the selection of biologically active compounds for Alzheimer's disease (AD) from a completed high-content high-throughput screen (HCS) that had only contained the original markers. The ML method identified novel compounds that effectively blocked tau aggregation, which had been missed by traditional screening approaches unguided by ML. The method improved triaging efficiency of compound rankings over conventional rankings by raw image channels. We reproduced this ML pipeline on a biologically independent cancer-based dataset, demonstrating its generalizability. The approach is disease-agnostic and applicable across diverse fluorescence microscopy datasets.

Because precision medicine is highly dependent on the accurate detection of biomarkers, there is an increasing need for standardized and robust technologies that measure RNA biomarkers in situ in clinical specimens. While grind-and-bind assays like RNAseq and quantitative RT-PCR enable highly sensitive gene expression measurements, they also require RNA extraction and thus prevent valuable expression analysis within the morphological tissue context. The in situ hybridization (ISH) assay described here can detect RNA target sequences as short as 50 nucleotides at single-nucleotide resolution and at the single-cell level. This assay is complementary to the previously developed commercial assay and enables sensitive and specific in situ detection of splice variants, short targets, and point mutations within the tissue. In this protocol, probes were designed to target unique exon junctions for two clinically important splice variants, EGFRvIII and METΔ14. The detection of short target sequences was demonstrated by the specific detection of CDR3 sequences of T-cell receptors α and β in the Jurkat T-cell line. Also shown is the utility of this ISH assay for the distinction of RNA target sequences at single-nucleotide resolution (point mutations) through the visualization of EGFR L858R and KRAS G12A single-nucleotide variations in cell lines using automated staining platforms. In summary, the protocol shows a specialized RNA ISH assay that enables the detection of splice variants, short sequences, and mutations in situ for manual performance and on automated stainers.

Because precision medicine is highly dependent on the accurate detection of biomarkers, there is an increasing need for standardized and robust technologies that measure RNA biomarkers in situ in clinical specimens. While grind-and-bind assays like RNAseq and quantitative RT-PCR enable highly sensitive gene expression measurements, they also require RNA extraction and thus prevent valuable expression analysis within the morphological tissue context. The in situ hybridization (ISH) assay described here can detect RNA target sequences as short as 50 nucleotides at single-nucleotide resolution and at the single-cell level. This assay is complementary to the previously developed commercial assay and enables sensitive and specific in situ detection of splice variants, short targets, and point mutations within the tissue. In this protocol, probes were designed to target unique exon junctions for two clinically important splice variants, EGFRvIII and METΔ14. The detection of short target sequences was demonstrated by the specific detection of CDR3 sequences of T-cell receptors α and β in the Jurkat T-cell line. Also shown is the utility of this ISH assay for the distinction of RNA target sequences at single-nucleotide resolution (point mutations) through the visualization of EGFR L858R and KRAS G12A single-nucleotide variations in cell lines using automated staining platforms. In summary, the protocol shows a specialized RNA ISH assay that enables the detection of splice variants, short sequences, and mutations in situ for manual performance and on automated stainers.

Monocular enucleation (ME) drastically affects the contralateral visual cortex, where plasticity phenomena drive specific adaptations to compensate for the unilateral loss of vision. In adult mice, complete reactivation of deprived visual cortex involves an early visually driven recovery followed by multimodal plasticity 3 to 7 weeks post ME (Van Brussel et al. [2011] Cereb. Cortex 21:2133-2146). Here, we specifically investigated the age dependence of the onset and the exact timing of both ME-induced reactivation processes by comparing cortical activity patterns of mice enucleated at postnatal day (P) 45, 90, or 120. A swifter open-eye potentiated reactivation characterized the binocular visual cortex of P45 mice. Nevertheless, even after 7 weeks, the reactivation remained incomplete, especially in the monocular cortex medial to V1. In comparison with P45, emergent cross-modal participation was demonstrated in P90 animals, although robust reactivation similar to enucleated adults (P120) was not achieved yet. Concomitantly, at 7 weeks post ME, somatosensory and auditory cortex shifted from a hypoactive state in P45 to hyperactivity in P120. Thus, we provide evidence for a presensitive period in which gradual recruitment of cross-modal recovery upon long-term ME coincides with the transition from adolescence to adulthood in mice.

Neurobeachin (NBEA), a brain-enriched multidomain scaffolding protein involved in neurotransmitter release and synaptic functioning, has been identified as a candidate gene for autism spectrum disorder (ASD) in four unrelated patients haploinsufficient for NBEA. The aim of this study was to map the behavioral phenotype of Nbea(+/-) mice in order to understand its contribution to the pathogenesis of ASD. ASD-like behavioral variables of Nbea(+/-) mice were related to basal neuronal activity in different brain regions by in situ hybridizations and extracellular field recordings of synaptic plasticity in hippocampal cornu ammonis 1 (CA1) region. Levels of BDNF and phosphorylated cAMP response element-binding protein (CREB) were measured in an attempt to investigate putatively underlying changes in these neuromolecules. Nbea(+/-) mice exhibit several ASD-like features, including changes in self-grooming behavior, social behaviors, conditioned fear responses, and spatial learning and memory, which coincided with enhanced long-term potentiation (LTP) in their CA1 region. The observed alterations in learning and memory and hippocampal LTP are concomitant with decreased expression of the immediate early gene zif268 in dorsomedial striatum and hippocampal CA1 region, increased CREB phosphorylation, and increased hippocampal BDNF expression. These findings indicate that Nbea haploinsufficiency leads to various molecular and cellular changes that affect neuroplasticity and behavioral functions in mice, and could thus underlie the ASD symptomatology in NBEA deficient humans. ispartof: Neurobiology Of Disease vol:51 pages:144-151 ispartof: location:United States status: published

The Morris water maze (MWM) spatial learning task has been demonstrated to involve a cognitive switch of action control to serve the transition from an early towards a late learning phase. However, the molecular mechanisms governing this switch are largely unknown. We employed MALDI MS imaging (MSI) to screen for changes in expression of small proteins in brain structures implicated in the different learning phases. We compared mice trained for 3days and 30days in the MWM, reflecting an early and a late learning phase in relation to the acquisition of a spatial learning task. An ion with m/z of 6724, identified as PEP-19/pcp4 by top-down tandem MS, was detected at higher intensity in the dorsal striatum of the late learning phase group compared with the early learning phase group. In addition, mass spectrometric analysis of synaptosomes confirmed the presence of PEP-19/pcp4 at the synapse. PEP-19/pcp4 has previously been identified as a critical determinant of synaptic plasticity in locomotor learning. Our findings extend PEP-19/pcp4 function to spatial learning in the forebrain and put MSI forward as a valid and unbiased research strategy for the discovery and identification of the molecular machinery involved in learning, memory and synaptic plasticity. publisher: Elsevier articletitle: MS imaging and mass spectrometric synaptosome profiling identify PEP-19/pcp4 as a synaptic molecule involved in spatial learning in mice journaltitle: Biochimica et Biophysica Acta (BBA) - Proteins and Proteomics articlelink: http://dx.doi.org/10.1016/j.bbapap.2016.10.007 content_type: article copyright: © 2016 Elsevier B.V. All rights reserved. ispartof: Biochimica et Biophysica Acta vol:1865 issue:7 pages:936-945 ispartof: location:Netherlands status: published

The presence of immunosuppressive molecules and cells in the tumor microenvironment (TME) can lead to T cell dysfunction. CD8-positive cytotoxic T cells (CTLs) are ineffective in killing tumor cells primarily due to upregulated expression of inhibitory checkpoint molecules and decreased production of effective cytokines. In addition, immune suppressive cell types such as regulatory T cells (Tregs) and tumor associated macrophages (TAMs) are recruited to the TME, further establishing a suppressive immune environment. In this study, we evaluated expression profiles of key immunosuppressive molecules and cell types by applying RNAscope® assay, a highly specific and sensitive in situ hybridization (ISH) technology, and dual ISH-IHC staining. First, we evaluated CD8-positive cell infiltration in TME of archived human tissues from non-small cell lung cancer and ovarian cancer. Selected tissues with either high or low CD8-positive cell number (CD8-high or CD8-low) were evaluated for (1) the presence of Tregs (FOXP3+CD4+) and TAMs (CD163+, including IL10 and CCL22), (2) the expression of immune checkpoint molecules including PD1, PD-L1, TIM3, and LAG3, (3) the expression of immune suppressive molecules IDO1 and TGFβ, and (4) IFNγ expression in CD8-positive subsets. Examination of immune inhibitory molecules expressed in single cells in the tumor and stromal microenvironment revealed that in general, CD8-high tissues expressed higher level of immune checkpoint molecules, often co-expressed in the same individual cells in the same TME, while the expression of IDO1 and TGFβ was independent of CD8-positive cell inflammation. Tregs and TAMs often co-existed with IFNγ-positive CTLs in the same TME. Unexpectedly, all investigated inhibitory molecules were expressed in both tumor cells and stromal/immune cells in some tumors. Beyond PD-L1, immune checkpoint molecules PD1, TIM3, and LAG3 were frequently expressed in tumor cells but at lower level than in immune cells. Expression of IDO1 and TGFβ was observed in many cell types, including tumor cells, with various expression levels in each tumor cell. The single-cell tumor expression profiles suggest a potential tumor-intrinsic mechanism of expression for these inhibitory molecules. This exploratory study highlights the potential of RNAscope® ISH to better understand the cellular and molecular suppressive mechanisms associated with T cell dysfunction and exhaustion in the TME. The robust RNAscope® ISH platform is well suited for evaluating critical secreted factors and other key molecules in a highly sensitive and cell type-specific manner. As multiple therapeutic approaches to augment the CTL function are being developed, the presented method may facilitate the identification and development of key biomarkers to stratify patients based on their specific tumor and immune cell states. Citation Format: Annelies Laeremans, Na Li, Jeff Kim, Xiao-Jun Ma, Emily Park. Evaluation of potential factors contributing to the exhaustion of T lymphocytes in the tumor microenvironment [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2018; 2018 Apr 14-18; Chicago, IL. Philadelphia (PA): AACR; Cancer Res 2018;78(13 Suppl):Abstract nr 1022.

As the number and diversity of cellular and signaling pathway therapeutic targets in immuno-oncology increases, more therapy combinations are aimed at multiple cell types in the tumor microenvironment (TME). To develop rational combinations of therapies that will be effective in any individual patient, multivariate biomarker assays will be required to understand each patient's specific tumor and immune profile. Understanding the mechanistic effects of immunotherapy includes the tissue context of direct immunotherapy targets and downstream effector molecules such as secreted cytokines. Although the content of tumor-infiltrating immune cells and gene expression of the total tumor can be ascertained through several methods, spatial arrangements and proximity of cells and co-localization of biomarkers can only be achieved with tissue-based assays. Duplex chromogenic in situ hybridization assays using the RNAscope platform allows for the visualization of gene expression of mRNA targets directly in tissue for multiple cell types or biomarkers. Computational Tissue Analysis (cTA™) was used to quantify cellular spatial distributions including regional density maps, proximity measurements, and colocalization of biomarkers in both the tumor nests and the surrounding stroma that would be challenging by visual inspection of duplex RNAscope assays in non-small cell lung cancer (NSCLC) tissue microarrays (TMAs). Often, neither immune effector cells nor the therapeutic target is sufficient in isolation to understand blocked anti-tumor immune responses and therefore the potential efficacy of a single or combination therapeutic strategy. Multiplex RNAscope assays and cTA™ in combination allow the assessment of end points that measure spatial relationships between cell types expressing certain biomarkers. As these are performed in the context of the tissue microarchitecture within and across multiple tissue sections, they are a significant advancement over traditional tissue-based manual end points. Citation Format: Jenifer Caldara, Brooke Hirsch, Joseph Krueger, Chris Bunker, Jeff Kim, Annelies Laeremans, Mohammed Qutaish, Allison Harney. Analysis of multiplexed immunotherapy targets and secreted ligands using computational tumor microenvironment profiling [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2018; 2018 Apr 14-18; Chicago, IL. Philadelphia (PA): AACR; Cancer Res 2018;78(13 Suppl):Abstract nr 1720.

Cancer immunotherapy using monoclonal antibodies targeting inhibitory immune checkpoint molecules is being established as a new paradigm in cancer treatment. This crucial strategy involves inhibition of the interaction between immune checkpoint receptors, expressed on the immune cells, and their respective ligands, expressed on antigen-presenting cells. While this receptor-ligand concept is well accepted in infection immunology, there have been numerous reports on the expression of immune checkpoint molecules in tumor cells. In addition to well-characterized tumor-intrinsic expression of PD11 and PD-L12, many other checkpoint molecules are associated with tumor cells3, conferring important impact on tumor biology and clinical consequences. In this study, we evaluated in situ single-cell expression profiles of immune checkpoint molecules in the tumor microenvironment (TME) of archived FFPE tissues from multiple solid cancers, including breast, kidney, ovarian, stomach, colorectal, and non-small cell lung cancer. Applying the RNAscope® assay, a highly specific and sensitive in situ hybridization (ISH) technology, tissue microarrays consisting of 20-35 FFPE tumors per each cancer type were stained for key therapeutic targets including PD1, PD-L1, TIM3, and LAG3. We observed that, in addition to PD-L1, all evaluated immune checkpoint molecules were expressed in the tumor cells of multiple tumor types though at a lower level than in immune cells. While there was notable heterogeneity of expression in different tumor regions in some samples, the single-cell expression pattern of each checkpoint molecule across all tumor cells in each region suggested a potential tumor-intrinsic mechanism for the expression of these molecules. In selected lung and ovarian cancers, fluorescence multiplex ISH-IHC staining confirmed that multiple different checkpoint molecules were co-expressed together in individual tumor cells. These findings add to the growing evidence that immune checkpoint genes can be expressed in tumor cells in addition to immune cells, which will be missed by gene expression analysis techniques using bulk tissue. The RNAscope® ISH platform is especially well suited for this type of analysis since it allows for assessing cell type-specific expression of any gene within the native tissue architecture even when it is expressed at very low levels. The approach illustrated in this study may help to better understand the anti-tumor activities of immune checkpoint inhibitors and provide new insights into better predictive biomarkers and therapeutic strategies. References 1. Kleffel et al. Cell. 2015 2. Clark et al. Cancer Res. 2016 3. Marcucci et al. BBA - Review. 2017 Citation Format: Annelies Laeremans, Na Li, Jeff Kim, Xiao-Jun Ma, Emily Park. Expression of tumor cell-associated immune checkpoint molecules in multiple human solid tumors [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2018; 2018 Apr 14-18; Chicago, IL. Philadelphia (PA): AACR; Cancer Res 2018;78(13 Suppl):Abstract nr 715.

176 Background: Interactions between tumor and immune cells in the tumor microenvironment (TME) play a key role in tumor progression and treatment response with accumulating evidence indicating a crucial role for tumor infiltrating immune cells. Although infiltrating cytotoxic T lymphocytes (CTLs) have been correlated with improved clinical outcome, they are ineffective in eradicating tumors due to their inhibition by immune checkpoint molecules. Immune checkpoint inhibitors have demonstrated therapeutic efficacy and durable response for several tumor types including non-small cell lung cancer (NSCLC). However, the majority of patients are resistant or relapse after initial response. Characterizing the TME for checkpoint expression with single-cell and spatial resolution can provide critical insight into new immunotherapeutic strategies and identify new predictive biomarkers for stratifying and identifying patients most likely to benefit from immunotherapy including PD-1/PD-L1 immune checkpoint blockade. Methods: Using RNAscope in situ hybridization, we evaluated in situ co-expression profiles of therapeutic checkpoint targets at single-cell level in the TME of 56 archived NSCLC FFPE tissues. Results: Checkpoint molecules including PD1, PD-L1, PD-L2, TIM3, LAG3, CTLA-4 and GITR were visualized in a highly specific and sensitive manner in individual cells within tissue morphological context. Multiple checkpoint molecules were detected in the same immune environment, especially in highly inflamed tumors. In addition to PD-L1, tumor cell-intrinsic expression of PD1, TIM3, LAG3, and PD-L2 was observed in a subset of samples. Furthermore, co-expression of therapeutic checkpoint targets including PD1, LAG3, and TIM3 was observed in infiltrating immune cells and tumor cells. Conclusions: Single-cell co-expression profiles of checkpoint molecules could shed light on how cancer cells evade the host immune surveillance and develop resistance against checkpoint blockades. Also, they could reveal valuable insights into combinatorial therapies for checkpoint markers co-expressed by the patient’s immune cells in the TME.

The hippocampus (HC) has been suggested to play a role in transitive inference (TI) on an ordered sequence of stimuli. However, it has remained unclear whether HC is involved in the expression of TI, or rather contributes to TI through its role in the acquisition of the sequence of elements (Frank, Rudy, & O'Reilly, 2003). Presently, the authors compared the effects of excitotoxic dorsal HC lesions in C57BL mice that received surgery before or after they were trained to discriminate between pairs of visual stimuli. Performance on a subsequent TI task was worse in mice with pretraining lesions than in those with posttraining lesions, which showed similar performance to shams without lesions. This indicates that HC is not involved in the expression of TI, but may merely help to acquire the underlying representations required for TI.

We explored differential protein expression profiles in the mouse forebrain at different stages of postnatal development, including 10-day (P10), 30-day (P30), and adult (Ad) mice, by large-scale screening of proteome maps using two-dimensional difference gel electrophoresis. Mass spectrometry analysis resulted in the identification of 251 differentially expressed proteins. Most molecular changes were observed between P10 compared to both P30 and Ad. Computational ingenuity pathway analysis (IPA) confirmed these proteins as crucial molecules in the biological function of nervous system development. Moreover, IPA revealed Semaphorin signaling in neurons and the protein ubiquitination pathway as essential canonical pathways in the mouse forebrain during postnatal development. For these main biological pathways, the transcriptional regulation of the age-dependent expression of selected proteins was validated by means of in situ hybridization. In conclusion, we suggest that proteolysis and neurite outgrowth guidance are key biological processes, particularly during early brain maturation. ispartof: Journal of Experimental Neuroscience vol:7 pages:60-74 ispartof: location:United States status: published

Although the Morris water maze (MWM) is the most frequently used protocol to examine hippocampus-dependent learning in mice, not much is known about the spatio-temporal dynamics of underlying plasticity processes. Here, we studied molecular and cellular hippocampal plasticity mechanisms during early and late phases of spatial learning in the MWM. Quantitative in situ hybridization for the immediate early genes zif268 and Homer1a (H1a) revealed phase-dependent differences in their expression between areas CA1 and CA3. During the initial learning phase, CA1 expression levels of the molecular plasticity marker H1a, but not of the activity reporter gene zif268, were related to task proficiency; whereas no learning-specific changes could be detected in CA3. Simultaneously, the ratio of surface-expressed NMDAR subunits NR2A and NR2B was downregulated as measured by acute slice biotinylation assay, while the total number of surface NMDARs was unaltered. When intrinsic 'somatic' and synaptic plasticity in the CA1-region of hippocampal slices were examined, we found that early learning promotes intrinsic neuronal plasticity as manifested by a reduction of spike frequency adaptation and postburst afterhyperpolarization. At the synaptic level, however, maintenance of long-term potentiation (LTP) in all learning groups was impaired which is most likely due to 'intrinsic' learning-induced LTP which occluded any further electrically induced LTP. Late learning, in contrast, was characterized by re-normalized H1a, NR2A and NR2B expression and neuronal firing, yet a further strengthening of learning-induced LTP. Together, our data support a precisely timed cascade of complex molecular and subcellular transformations occurring from early to late MWM learning.

Monocular enucleation (ME) drastically affects the contralateral visual cortex, where plasticity phenomena drive specific adaptations to compensate for the unilateral loss of vision. In adult mice, complete reactivation of deprived visual cortex involves an early visually driven recovery followed by multimodal plasticity 3 to 7 weeks post ME (Van Brussel et al. [2011] Cereb. Cortex 21:2133-2146). Here, we specifically investigated the age dependence of the onset and the exact timing of both ME-induced reactivation processes by comparing cortical activity patterns of mice enucleated at postnatal day (P) 45, 90, or 120. A swifter open-eye potentiated reactivation characterized the binocular visual cortex of P45 mice. Nevertheless, even after 7 weeks, the reactivation remained incomplete, especially in the monocular cortex medial to V1. In comparison with P45, emergent cross-modal participation was demonstrated in P90 animals, although robust reactivation similar to enucleated adults (P120) was not achieved yet. Concomitantly, at 7 weeks post ME, somatosensory and auditory cortex shifted from a hypoactive state in P45 to hyperactivity in P120. Thus, we provide evidence for a presensitive period in which gradual recruitment of cross-modal recovery upon long-term ME coincides with the transition from adolescence to adulthood in mice.

The multiple memory systems hypothesis posits that dorsal striatum and hippocampus are central nodes in independent memory systems, supporting response-based and place-based learning, respectively. Although our understanding of the function of hippocampus within this framework is relatively well established, the contribution of dorsal striatum is less clear. This in part seems to be due to the heterogeneous nature of dorsal striatum, which receives extensive topographically organized projections from higher cortical areas. Here we quantified neural activity in the intact brain while mice and humans acquired analogous versions of the Morris water maze. We found that dorsomedial striatum and medial prefrontal cortex support the initial acquisition of what is typically considered a hippocampus-dependent spatial learning task. We suggest that the circuit involving dorsomedial striatum and medial prefrontal cortex identified here plays a more task-independent role in early learning than currently thought. Furthermore, our results demonstrate that dorsomedial and dorsolateral striatum serve fundamentally different roles during place learning. The remarkably high degree of anatomical overlap in brain function between mouse and human observed in our study emphasizes the extent of convergence achievable with a well-matched multilevel approach. ispartof: Proceedings Of The National Academy Of Sciences Of The United States Of America vol:110 issue:8 pages:3131-3136 ispartof: location:United States status: published

Neonatal lesioning of the ventral hippocampus (vHc) in rats has served as a useful heuristic animal model to elucidate neurodevelopmental mechanisms of schizophrenia (SCZ). In the current study we have established that this procedure can be applied to model SCZ symptomatology in mice. Neonatal mice (postnatal day 6) were anaesthetised by hypothermia and electrolytic lesions of the vHc were induced. We observed locomotor hyperactivity at prepubertal and adult age and hypersensitivity to amphetamine. Furthermore, working memory deficits were observed in Y-maze (spontaneous alternation) and T-maze (exploration of a novel arm) test protocols. Decreased anxious behaviour in the elevated plus maze and increased sociability were also observed. These changes were dependent on lesion size. No differences were observed in prepulse inhibition of the startle reflex, latent inhibition, spatial memory (Morris water maze), problem solving capacities (syringe puzzle) and ability to discriminate between different unfamiliar mice. The presented findings might further help to identify neurobiological mechanisms of neurodevelopmental disorders.

AMIGO2, or amphoterin-induced gene and ORF (open reading frame) 2, belongs to the leucine-rich repeats and immunoglobulin superfamilies. The protein is a downstream target of calcium-dependent survival signals and, therefore, promotes neuronal survival. Here, we describe the mRNA distribution pattern of AMIGO2 throughout the mouse brain with special emphasis on the hippocampus. In the Ammon's horn, a detailed comparison between the subregional mRNA expression patterns of AMIGO2 and Pcp4 (Purkinje cell protein 4)--a known molecular marker of hippocampal CA2 (Cornu Ammonis 2)--revealed a prominent AMIGO2 mRNA expression level in both the CA2 and the CA3a (Cornu Ammonis 3a) subregion of the dorsal and ventral hippocampus. Since this CA2/CA3a region is particularly resistant to neuronal injury and neurotoxicity [Stanfield and Cowan (Brain Res 309(2):299–307 1984); Sloviter (J Comp Neurol 280(2):183–196 1989); Leranth and Ribak (Exp Brain Res 85(1):129–136 1991); Young and Dragunow (Exp Neurol 133(2):125–137 1995); Ochiishi et al. (Neurosci 93(3):955–967 1999)], we suggest that the expression pattern of AMIGO2 indeed fits with its involvement in neuroprotection. ispartof: Brain Structure and Function vol:218 issue:1 pages:123-130 ispartof: location:Germany status: published

Phosphodiesterase 10A (PDE10A) hydrolyzes both cAMP and cGMP, and is a key element in the regulation of medium spiny neuron (MSN) activity in the striatum. In the present report, we investigated the effects of targeted disruption of PDE10A on spatial learning and memory as well as aversive and appetitive conditioning in C57BL/6 J mice. Because of its putative role in motivational processes and reward learning, we also determined the expression of the immediate early gene zif268 in striatum and anterior cingulate cortex. Animals showed decreased response rates in scheduled appetitive operant conditioning, as well as impaired aversive conditioning in a passive avoidance task. Morris water maze performance revealed not-motor related spatial learning and memory deficits. Anxiety and social explorative behavior was not affected in PDE10A-deficient mice. Expression of zif268 was increased in striatum and anterior cingulate cortex, which suggests alterations in the neural connections between striatum and anterior cingulate cortex in PDE10A-deficient mice. The changes in behavior and plasticity in these PDE10A-deficient mice were in accordance with the proposed role of striatal MSNs and corticostriatal connections in evaluative salience attribution.

Retinal lesions induce a topographic reorganization in the corresponding lesion projection zone (LPZ) in the visual cortex of adult cats. To gain a better insight into the reactivation dynamics, we investigated the alterations in cortical activity throughout area 17. We implemented in situ hybridization and real-time polymerase chain reaction to analyze the spatiotemporal expression patterns of the activity marker genes zif268 and c-fos. The immediate early gene (IEG) data confirmed a strong and permanent activity decrease in the center of the LPZ as previously described by electrophysiology. A recovery of IEG expression was clearly measured in the border of the LPZ. We were able to register reorganization over 2.5--6 mm. We also present evidence that the central retinal lesions concomitantly influence the activity in far peripheral parts of area 17. Its IEG expression levels appeared dependent of time and distance from the LPZ. We therefore propose that coupled changes in activity occur inside and outside the LPZ. In conclusion, alterations in activity reporter gene expression throughout area 17 contribute to the lesioninduced functional reorganization.