@article{LechermeierZimmerLueffeetal.2019, author = {Lechermeier, Carina G. and Zimmer, Frederic and L{\"u}ffe, Teresa M. and Lesch, Klaus-Peter and Romanos, Marcel and Lillesaar, Christina and Drepper, Carsten}, title = {Transcript analysis of zebrafish GLUT3 genes, slc2a3a and slc2a3b, define overlapping as well as distinct expression domains in the zebrafish (Danio rerio) central nervous system}, series = {Frontiers in Molecular Neuroscience}, volume = {12}, journal = {Frontiers in Molecular Neuroscience}, number = {199}, doi = {10.3389/fnmol.2019.00199}, url = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-201797}, year = {2019}, abstract = {The transport of glucose across the cell plasma membrane is vital to most mammalian cells. The glucose transporter (GLUT; also called SLC2A) family of transmembrane solute carriers is responsible for this function in vivo. GLUT proteins encompass 14 different isoforms in humans with different cell type-specific expression patterns and activities. Central to glucose utilization and delivery in the brain is the neuronally expressed GLUT3. Recent research has shown an involvement of GLUT3 genetic variation or altered expression in several different brain disorders, including Huntington's and Alzheimer's diseases. Furthermore, GLUT3 was identified as a potential risk gene for multiple psychiatric disorders. To study the role of GLUT3 in brain function and disease a more detailed knowledge of its expression in model organisms is needed. Zebrafish (Danio rerio) has in recent years gained popularity as a model organism for brain research and is now well-established for modeling psychiatric disorders. Here, we have analyzed the sequence of GLUT3 orthologs and identified two paralogous genes in the zebrafish, slc2a3a and slc2a3b. Interestingly, the Glut3b protein sequence contains a unique stretch of amino acids, which may be important for functional regulation. The slc2a3a transcript is detectable in the central nervous system including distinct cellular populations in telencephalon, diencephalon, mesencephalon and rhombencephalon at embryonic and larval stages. Conversely, the slc2a3b transcript shows a rather diffuse expression pattern at different embryonic stages and brain regions. Expression of slc2a3a is maintained in the adult brain and is found in the telencephalon, diencephalon, mesencephalon, cerebellum and medulla oblongata. The slc2a3b transcripts are present in overlapping as well as distinct regions compared to slc2a3a. Double in situ hybridizations were used to demonstrate that slc2a3a is expressed by some GABAergic neurons at embryonic stages. This detailed description of zebrafish slc2a3a and slc2a3b expression at developmental and adult stages paves the way for further investigations of normal GLUT3 function and its role in brain disorders.}, language = {en} } @article{GottschalkRichterZiegleretal.2019, author = {Gottschalk, Michael G. and Richter, Jan and Ziegler, Christiane and Schiele, Miriam A. and Mann, Julia and Geiger, Maximilian J. and Schartner, Christoph and Homola, Gy{\"o}rgy A. and Alpers, Georg W. and B{\"u}chel, Christian and Fehm, Lydia and Fydrich, Thomas and Gerlach, Alexander L. and Gloster, Andrew T. and Helbig-Lang, Sylvia and Kalisch, Raffael and Kircher, Tilo and Lang, Thomas and Lonsdorf, Tina B. and Pan{\´e}-Farr{\´e}, Christiane A. and Str{\"o}hle, Andreas and Weber, Heike and Zwanzger, Peter and Arolt, Volker and Romanos, Marcel and Wittchen, Hans-Ulrich and Hamm, Alfons and Pauli, Paul and Reif, Andreas and Deckert, J{\"u}rgen and Neufang, Susanne and H{\"o}fler, Michael and Domschke, Katharina}, title = {Orexin in the anxiety spectrum: association of a HCRTR1 polymorphism with panic disorder/agoraphobia, CBT treatment response and fear-related intermediate phenotypes}, series = {Translational Psychiatry}, volume = {9}, journal = {Translational Psychiatry}, doi = {10.1038/s41398-019-0415-8}, url = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-227479}, year = {2019}, abstract = {Preclinical studies point to a pivotal role of the orexin 1 (OX1) receptor in arousal and fear learning and therefore suggest the HCRTR1 gene as a prime candidate in panic disorder (PD) with/without agoraphobia (AG), PD/AG treatment response, and PD/AG-related intermediate phenotypes. Here, a multilevel approach was applied to test the non-synonymous HCRTR1 C/T Ile408Val gene variant (rs2271933) for association with PD/AG in two independent case-control samples (total n = 613 cases, 1839 healthy subjects), as an outcome predictor of a six-weeks exposure-based cognitive behavioral therapy (CBT) in PD/AG patients (n = 189), as well as with respect to agoraphobic cognitions (ACQ) (n = 483 patients, n = 2382 healthy subjects), fMRI alerting network activation in healthy subjects (n = 94), and a behavioral avoidance task in PD/AG pre- and post-CBT (n = 271). The HCRTR1 rs2271933 T allele was associated with PD/AG in both samples independently, and in their meta-analysis (p = 4.2 × 10-7), particularly in the female subsample (p = 9.8 × 10-9). T allele carriers displayed a significantly poorer CBT outcome (e.g., Hamilton anxiety rating scale: p = 7.5 × 10-4). The T allele count was linked to higher ACQ sores in PD/AG and healthy subjects, decreased inferior frontal gyrus and increased locus coeruleus activation in the alerting network. Finally, the T allele count was associated with increased pre-CBT exposure avoidance and autonomic arousal as well as decreased post-CBT improvement. In sum, the present results provide converging evidence for an involvement of HCRTR1 gene variation in the etiology of PD/AG and PD/AG-related traits as well as treatment response to CBT, supporting future therapeutic approaches targeting the orexin-related arousal system.}, language = {en} } @article{UllrichWeberPostetal.2018, author = {Ullrich, M and Weber, M and Post, A M and Popp, S and Grein, J and Zechner, M and Gonz{\´a}lez, H Guerrero and Kreis, A and Schmitt, A G and {\"U}ҫeyler, N and Lesch, K-P and Schuh, K}, title = {OCD-like behavior is caused by dysfunction of thalamo-amygdala circuits and upregulated TrkB/ERK-MAPK signaling as a result of SPRED2 deficiency}, series = {Molecular Psychiatry}, volume = {23}, journal = {Molecular Psychiatry}, doi = {10.1038/mp.2016.232}, url = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-232096}, pages = {444-458}, year = {2018}, abstract = {Obsessive-compulsive disorder (OCD) is a common neuropsychiatric disease affecting about 2\% of the general population. It is characterized by persistent intrusive thoughts and repetitive ritualized behaviors. While gene variations, malfunction of cortico-striato-thalamo-cortical (CSTC) circuits, and dysregulated synaptic transmission have been implicated in the pathogenesis of OCD, the underlying mechanisms remain largely unknown. Here we show that OCD-like behavior in mice is caused by deficiency of SPRED2, a protein expressed in various brain regions and a potent inhibitor of Ras/ERK-MAPK signaling. Excessive self-grooming, reflecting OCD-like behavior in rodents, resulted in facial skin lesions in SPRED2 knockout (KO) mice. This was alleviated by treatment with the selective serotonin reuptake inhibitor fluoxetine. In addition to the previously suggested involvement of cortico-striatal circuits, electrophysiological measurements revealed altered transmission at thalamo-amygdala synapses and morphological differences in lateral amygdala neurons of SPRED2 KO mice. Changes in synaptic function were accompanied by dysregulated expression of various pre- and postsynaptic proteins in the amygdala. This was a result of altered gene transcription and triggered upstream by upregulated tropomyosin receptor kinase B (TrkB)/ERK-MAPK signaling in the amygdala of SPRED2 KO mice. Pathway overactivation was mediated by increased activity of TrkB, Ras, and ERK as a specific result of SPRED2 deficiency and not elicited by elevated brain-derived neurotrophic factor levels. Using the MEK inhibitor selumetinib, we suppressed TrkB/ERK-MAPK pathway activity in vivo and reduced OCD-like grooming in SPRED2 KO mice. Altogether, this study identifies SPRED2 as a promising new regulator, TrkB/ERK-MAPK signaling as a novel mediating mechanism, and thalamo-amygdala synapses as critical circuitry involved in the pathogenesis of OCD.}, language = {en} } @article{LueffeBauerGiogaetal.2022, author = {L{\"u}ffe, Teresa M. and Bauer, Moritz and Gioga, Zoi and {\"O}zbay, Duru and Romanos, Marcel and Lillesaar, Christina and Drepper, Carsten}, title = {Loss-of-Function Models of the Metabotropic Glutamate Receptor Genes Grm8a and Grm8b Display Distinct Behavioral Phenotypes in Zebrafish Larvae (Danio rerio)}, series = {Frontiers in Molecular Neuroscience}, volume = {15}, journal = {Frontiers in Molecular Neuroscience}, issn = {1662-5099}, doi = {10.3389/fnmol.2022.901309}, url = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-277429}, year = {2022}, abstract = {Members of the family of metabotropic glutamate receptors are involved in the pathomechanism of several disorders of the nervous system. Besides the well-investigated function of dysfunctional glutamate receptor signaling in neurodegenerative diseases, neurodevelopmental disorders (NDD), like autism spectrum disorders (ASD) and attention-deficit and hyperactivity disorder (ADHD) might also be partly caused by disturbed glutamate signaling during development. However, the underlying mechanism of the type III metabotropic glutamate receptor 8 (mGluR8 or GRM8) involvement in neurodevelopment and disease mechanism is largely unknown. Here we show that the expression pattern of the two orthologs of human GRM8, grm8a and grm8b, have evolved partially distinct expression patterns in the brain of zebrafish (Danio rerio), especially at adult stages, suggesting sub-functionalization of these two genes during evolution. Using double in situ hybridization staining in the developing brain we demonstrate that grm8a is expressed in a subset of gad1a-positive cells, pointing towards glutamatergic modulation of GABAergic signaling. Building on this result we generated loss-of-function models of both genes using CRISPR/Cas9. Both mutant lines are viable and display no obvious gross morphological phenotypes making them suitable for further analysis. Initial behavioral characterization revealed distinct phenotypes in larvae. Whereas grm8a mutant animals display reduced swimming velocity, grm8b mutant animals show increased thigmotaxis behavior, suggesting an anxiety-like phenotype. We anticipate that our two novel metabotropic glutamate receptor 8 zebrafish models may contribute to a deeper understanding of its function in normal development and its role in the pathomechanism of disorders of the central nervous system.}, language = {en} } @article{RiveroAlhamaRibaKuetal.2021, author = {Rivero, Olga and Alhama-Riba, Judit and Ku, Hsing-Ping and Fischer, Matthias and Ortega, Gabriela and {\´A}lmos, P{\´e}ter and Diouf, David and van den Hove, Daniel and Lesch, Klaus-Peter}, title = {Haploinsufficiency of the Attention-Deficit/Hyperactivity Disorder Risk Gene St3gal3 in Mice Causes Alterations in Cognition and Expression of Genes Involved in Myelination and Sialylation}, series = {Frontiers in Genetics}, volume = {12}, journal = {Frontiers in Genetics}, issn = {1664-8021}, doi = {10.3389/fgene.2021.688488}, url = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-246855}, year = {2021}, abstract = {Genome wide association meta-analysis identified ST3GAL3, a gene encoding the beta-galactosidase-alpha-2,3-sialyltransferase-III, as a risk gene for attention-deficit/hyperactivity disorder (ADHD). Although loss-of-function mutations in ST3GAL3 are implicated in non-syndromic autosomal recessive intellectual disability (NSARID) and West syndrome, the impact of ST3GAL3 haploinsufficiency on brain function and the pathophysiology of neurodevelopmental disorders (NDDs), such as ADHD, is unknown. Since St3gal3 null mutant mice display severe developmental delay and neurological deficits, we investigated the effects of partial inactivation of St3gal3 in heterozygous (HET) knockout (St3gal3±) mice on behavior as well as expression of markers linked to myelination processes and sialylation pathways. Our results reveal that male St3gal3 HET mice display cognitive deficits, while female HET animals show increased activity, as well as increased cognitive control, compared to their wildtype littermates. In addition, we observed subtle alterations in the expression of several markers implicated in oligodendrogenesis, myelin formation, and protein sialylation as well as cell adhesion/synaptic target glycoproteins of ST3GAL3 in a brain region- and/or sex-specific manner. Taken together, our findings indicate that haploinsufficiency of ST3GAL3 results in a sex-dependent alteration of cognition, behavior and markers of brain plasticity.}, language = {en} } @article{DiehlSchmidLicataGoldhardtetal.2019, author = {Diehl-Schmid, Janine and Licata, Abigail and Goldhardt, Oliver and F{\"o}rstl, Hans and Yakushew, Igor and Otto, Markus and Anderl-Straub, Sarah and Beer, Ambros and Ludolph, Albert Christian and Landwehrmeyer, Georg Bernhard and Levin, Johannes and Danek, Adrian and Fliessbach, Klaus and Spottke, Annika and Fassbender, Klaus and Lyros, Epameinondas and Prudlo, Johannes and Krause, Bernd Joachim and Volk, Alexander and Edbauer, Dieter and Schroeter, Matthias Leopold and Drzezga, Alexander and Kornhuber, Johannes and Lauer, Martin and Grimmer, Timo}, title = {FDG-PET underscores the key role of the thalamus in frontotemporal lobar degeneration caused by C9ORF72 mutations}, series = {Translational Psychiatry}, volume = {9}, journal = {Translational Psychiatry}, organization = {FTLDc Study Group}, doi = {10.1038/s41398-019-0381-1}, url = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-225308}, year = {2019}, abstract = {C9ORF72 mutations are the most common cause of familial frontotemporal lobar degeneration (FTLD) and amyotrophic lateral sclerosis (ALS). MRI studies have investigated structural changes in C9ORF72-associated FTLD (C9FTLD) and provided first insights about a prominent involvement of the thalamus and the cerebellum. Our multicenter, 18F-fluorodeoxyglucose positron-emission tomography study of 22 mutation carriers with FTLD, 22 matched non-carriers with FTLD, and 23 cognitively healthy controls provided valuable insights into functional changes in C9FTLD: compared to non-carriers, mutation carriers showed a significant reduction of glucose metabolism in both thalami, underscoring the key role of the thalamus in C9FTLD. Thalamic metabolism did not correlate with disease severity, duration of disease, or the presence of psychotic symptoms. Against our expectations we could not demonstrate a cerebellar hypometabolism in carriers or non-carriers. Future imaging and neuropathological studies in large patient cohorts are required to further elucidate the central role of the thalamus in C9FTLD.}, language = {en} } @article{KohlGruendlerHuysetal.2015, author = {Kohl, S. and Gruendler, T. O. J. and Huys, D. and Sildatke, E. and Dembek, T. A. and Hellmich, M. and Vorderwulbecke, M. and Timmermann, L. and Ahmari, S. E. and Klosterkoetter, J. and Jessen, F. and Sturm, V. and Visser-Vandewalle, V. and Kuhn, J.}, title = {Effects of deep brain stimulation on prepulse inhibition in obsessive-compulsive disorder}, series = {Translational Psychiatry}, volume = {5}, journal = {Translational Psychiatry}, number = {e675}, doi = {10.1038/tp.2015.171}, url = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-138300}, year = {2015}, abstract = {Owing to a high response rate, deep brain stimulation (DBS) of the ventral striatal area has been approved for treatment-refractory obsessive-compulsive disorder (tr-OCD). Many basic issues regarding DBS for tr-OCD are still not understood, in particular, the mechanisms of action and the origin of side effects. We measured prepulse inhibition (PPI) in treatment-refractory OCD patients undergoing DBS of the nucleus accumbens (NAcc) and matched controls. As PPI has been used in animal DBS studies, it is highly suitable for translational research. Eight patients receiving DBS, eight patients with pharmacological treatment and eight age-matched healthy controls participated in our study. PPI was measured twice in the DBS group: one session with the stimulator switched on and one session with the stimulator switched off. OCD patients in the pharmacologic group took part in a single session. Controls were tested twice, to ensure stability of data. Statistical analysis revealed significant differences between controls and (1) patients with pharmacological treatment and (2) OCD DBS patients when the stimulation was switched off. Switching the stimulator on led to an increase in PPI at a stimulus-onset asynchrony of 200 ms. There was no significant difference in PPI between OCD patients being stimulated and the control group. This study shows that NAcc-DBS leads to an increase in PPI in tr-OCD patients towards a level seen in healthy controls. Assuming that PPI impairments partially reflect the neurobiological substrates of OCD, our results show that DBS of the NAcc may improve sensorimotor gating via correction of dysfunctional neural substrates. Bearing in mind that PPI is based on a complex and multilayered network, our data confirm that DBS most likely takes effect via network modulation.}, language = {en} } @article{KiserPoppSchmittBoehreretal.2019, author = {Kiser, Dominik P. and Popp, Sandy and Schmitt-B{\"o}hrer, Angelika G. and Strekalova, Tatyana and van den Hove, Daniel L. and Lesch, Klaus-Peter and Rivero, Olga}, title = {Early-life stress impairs developmental programming in Cadherin 13 (CDH13)-deficient mice}, series = {Progress in Neuropsychopharmacology \& Biological Psychiatry}, volume = {89}, journal = {Progress in Neuropsychopharmacology \& Biological Psychiatry}, doi = {10.1016/j.pnpbp.2018.08.010}, url = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-325859}, pages = {158-168}, year = {2019}, abstract = {Objective Cadherin-13 (CDH13), a member of the calcium-dependent cell adhesion molecule family, has been linked to neurodevelopmental disorders, including autism spectrum (ASD) and attention-deficit/hyperactivity (ADHD) disorders, but also to depression. In the adult brain, CDH13 expression is restricted e.g. to the presynaptic compartment of inhibitory GABAergic synapses in the hippocampus and Cdh13 knockout mice show an increased inhibitory drive onto hippocampal CA1 pyramidal neurons, leading to a shift in excitatory/inhibitory balance. CDH13 is also moderating migration of serotonergic neurons in the dorsal raphe nucleus, establishing projections preferentially to the thalamus and cerebellum during brain development. Furthermore, CDH13 is upregulated by chronic stress as well as in depression, suggesting a role in early-life adaptation to stressful experience. Here, we therefore investigated the interaction between Cdh13 variation and neonatal maternal separation (MS) in mice. Methods Male and female wild-type (Cdh13+/+), heterozygous (Cdh13+/-) and homozygous (Cdh13-/-) knockout mice exposed to MS, or daily handling as control, were subjected to a battery of behavioural tests to assess motor activity, learning and memory as well as anxiety-like behaviour. A transcriptome analysis of the hippocampus was performed in an independent cohort of mice which was exposed to MS or handling, but remained na{\"i}ve for behavioural testing. Results MS lead to increased anxiety-like behaviour in Cdh13-/- mice compared to the other two MS groups. Cdh13-/- mice showed a context-dependent effect on stress- and anxiety-related behaviour, impaired extinction learning following contextual fear conditioning and decreased impulsivity, as well as a mild decrease in errors in the Barnes maze and reduced risk-taking in the light-dark transition test after MS. We also show sex differences, with increased locomotor activity in female Cdh13-/- mice, but unaltered impulsivity and activity in male Cdh13-/- mice. Transcriptome analysis revealed several pathways associated with cell surface/adhesion molecules to be altered following Cdh13 deficiency, together with an influence on endoplasmic reticulum function. Conclusion MS resulted in increased stress resilience, increased exploration and an overall anxiolytic behavioural phenotype in male Cdh13+/+ and Cdh13+/- mice. Cdh13 deficiency, however, obliterated most of the effects caused by early-life stress, with Cdh13-/- mice exhibiting delayed habituation, no reduction of anxiety-like behaviour and decreased fear extinction. Our behavioural findings indicate a role of CDH13 in the programming of and adaptation to early-life stress. Finally, our transcriptomic data support the view of CDH13 as a neuroprotective factor as well as a mediator in cell-cell interactions, with an impact on synaptic plasticity.}, language = {en} } @article{RiveroSeltenSichetal.2015, author = {Rivero, O and Selten, MM and Sich, S and Popp, S and Bacmeister, L and Amendola, E and Negwer, M and Schubert, D and Proft, F and Kiser, D and Schmitt, AG and Gross, C and Kolk, SM and Strekalova, T and van den Hove, D and Resink, TJ and Kasir, N Nadif and Lesch, KP}, title = {Cadherin-13, a risk gene for ADHD and comorbid disorders, impacts GABAergic function in hippocampus and cognition}, series = {Translational Psychiatry}, volume = {5}, journal = {Translational Psychiatry}, number = {e655}, doi = {10.1038/tp.2015.152}, url = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-145218}, year = {2015}, abstract = {Cadherin-13 (CDH13), a unique glycosylphosphatidylinositol-anchored member of the cadherin family of cell adhesion molecules, has been identified as a risk gene for attention-deficit/hyperactivity disorder (ADHD) and various comorbid neurodevelopmental and psychiatric conditions, including depression, substance abuse, autism spectrum disorder and violent behavior, while the mechanism whereby CDH13 dysfunction influences pathogenesis of neuropsychiatric disorders remains elusive. Here we explored the potential role of CDH13 in the inhibitory modulation of brain activity by investigating synaptic function of GABAergic interneurons. Cellular and subcellular distribution of CDH13 was analyzed in the murine hippocampus and a mouse model with a targeted inactivation of Cdh13 was generated to evaluate how CDH13 modulates synaptic activity of hippocampal interneurons and behavioral domains related to psychopathologic (endo) phenotypes. We show that CDH13 expression in the cornu ammonis (CA) region of the hippocampus is confined to distinct classes of interneurons. Specifically, CDH13 is expressed by numerous parvalbumin and somatostatin-expressing interneurons located in the stratum oriens, where it localizes to both the soma and the presynaptic compartment. Cdh13\(^{-/-}\) mice show an increase in basal inhibitory, but not excitatory, synaptic transmission in CA1 pyramidal neurons. Associated with these alterations in hippocampal function, Cdh13\(^{-/-}\) mice display deficits in learning and memory. Taken together, our results indicate that CDH13 is a negative regulator of inhibitory synapses in the hippocampus, and provide insights into how CDH13 dysfunction may contribute to the excitatory/inhibitory imbalance observed in neurodevelopmental disorders, such as ADHD and autism.}, language = {en} } @article{FereroRiveroWaeldchenetal.2017, author = {Ferero, Andrea and Rivero, Olga and W{\"a}ldchen, Sina and Ku, Hsing-Ping and Kiser, Dominik P. and G{\"a}rtner, Yvonne and Pennington, Laura S. and Waider, Jonas and Gaspar, Patricia and Jansch, Charline and Edenhofer, Frank and Resink, Th{\´e}r{\`e}se J. and Blum, Robert and Sauer, Markus and Lesch, Klaus-Peter}, title = {Cadherin-13 Deficiency Increases Dorsal Raphe 5-HT Neuron Density and Prefrontal Cortex Innervation in the Mouse Brain}, series = {Frontiers in Cellular Neuroscience}, volume = {11}, journal = {Frontiers in Cellular Neuroscience}, number = {307}, doi = {10.3389/fncel.2017.00307}, url = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-170313}, year = {2017}, abstract = {Background: During early prenatal stages of brain development, serotonin (5-HT)-specific neurons migrate through somal translocation to form the raphe nuclei and subsequently begin to project to their target regions. The rostral cluster of cells, comprising the median and dorsal raphe (DR), innervates anterior regions of the brain, including the prefrontal cortex. Differential analysis of the mouse 5-HT system transcriptome identified enrichment of cell adhesion molecules in 5-HT neurons of the DR. One of these molecules, cadherin-13 (Cdh13) has been shown to play a role in cell migration, axon pathfinding, and synaptogenesis. This study aimed to investigate the contribution of Cdh13 to the development of the murine brain 5-HT system. Methods: For detection of Cdh13 and components of the 5-HT system at different embryonic developmental stages of the mouse brain, we employed immunofluorescence protocols and imaging techniques, including epifluorescence, confocal and structured illumination microscopy. The consequence of CDH13 loss-of-function mutations on brain 5-HT system development was explored in a mouse model of Cdh13 deficiency. Results: Our data show that in murine embryonic brain Cdh13 is strongly expressed on 5-HT specific neurons of the DR and in radial glial cells (RGCs), which are critically involved in regulation of neuronal migration. We observed that 5-HT neurons are intertwined with these RGCs, suggesting that these neurons undergo RGC-guided migration. Cdh13 is present at points of intersection between these two cell types. Compared to wildtype controls, Cdh13-deficient mice display increased cell densities in the DR at embryonic stages E13.5, E17.5, and adulthood, and higher serotonergic innervation of the prefrontal cortex at E17.5. Conclusion: Our findings provide evidence for a role of CDH13 in the development of the serotonergic system in early embryonic stages. Specifically, we indicate that Cdh13 deficiency affects the cell density of the developing DR and the posterior innervation of the prefrontal cortex (PFC), and therefore might be involved in the migration, axonal outgrowth and terminal target finding of DR 5-HT neurons. Dysregulation of CDH13 expression may thus contribute to alterations in this system of neurotransmission, impacting cognitive function, which is frequently impaired in neurodevelopmental disorders including attention-deficit/hyperactivity and autism spectrum disorders.}, language = {en} }