An In Vitro Study on Extracellular Vesicles From Adipose-Derived Mesenchymal Stem Cells in Protecting Stress Urinary Incontinence Through MicroRNA-93/F3 Axis.

Since the potential roles of extracellular vesicles secreted by adipose-derived mesenchymal stem cells (ADSCs) are not well understood in collagen metabolism, the purpose of this research was to evaluate the effects of ADSCs-extracellular vesicles in stress urinary incontinence and the regulatory mechanism of delivered microRNA-93 (miR-93). ADSCs were isolated and cultured, and ADSCs-extracellular vesicles were extracted and identified. Stress urinary incontinence primary fibroblasts or satellite cells were treated with ADSCs-extracellular vesicles to detect the expression of Elastin, Collagen I, and Collagen III in fibroblasts and Pax7 and MyoD in satellite cells. After transfecting ADSCs with miR-93 mimics or inhibitors, extracellular vesicles were isolated and treated with stress urinary incontinence primary fibroblasts or satellite cells to observe cell function changes. The online prediction and luciferase activity assay confirmed the targeting relationship between miR-93 and coagulation factor III (F3). The rescue experiment verified the role of ADSCs-extracellular vesicles carrying miR-93 in stress urinary incontinence primary fibroblasts and satellite cells by targeting F3. ADSCs-extracellular vesicles treatment upregulated expression of Elastin, Collagen I, and Collagen III in stress urinary incontinence primary fibroblasts and expression of Pax7 and MyoD in stress urinary incontinence primary satellite cells. miR-93 expression was increased in stress urinary incontinence primary fibroblasts or satellite cells treated with ADSCs-extracellular vesicles. Extracellular vesicles secreted by ADSCs could deliver miR-93 to fibroblasts and then negatively regulate F3 expression; ADSCs-extracellular vesicles could reverse the effect of F3 on extracellular matrix remodeling in stress urinary incontinence fibroblasts. miR-93 expression was also increased in stress urinary incontinence primary satellite cells treated by ADSCs-extracellular vesicles. Extracellular vesicles secreted by ADSCs were delivered to satellite cells through miR-93, which directly targets F3 expression and upregulates Pax7 and MyoD expression in satellite cells. Our study indicates that miR-93 delivered by ADSCs-extracellular vesicles could regulate extracellular matrix remodeling of stress urinary incontinence fibroblasts and promote activation of stress urinary incontinence satellite cells through targeting F3.

Epithelial exosomal contactin-1 promotes monocyte-derived dendritic cell-dominant T-cell responses in asthma.

BACKGROUND: Exosomes have emerged as a vital player in cell-cell communication; however, whether airway epithelial cell (AEC)-generated exosomes participate in asthma development remains unknown. OBJECTIVE: Our aims were to characterize the AEC-secreted exosomes and the potentially functional protein(s) that may contribute to the proinflammatory effects of AEC exosomes in the dendritic cell (DC)-dominant airway allergic models and to confirm their clinical significance in patients with asthma. METHODS: Mice were treated with exosomes derived from house dust mite (HDM)-stimulated AECs (HDM-AEC-EXOs) or monocyte-derived DCs primed by HDM and/or contactin-1 (CNTN1). The numbers of DCs in the lung were determined by flow cytometry. Proteomic analysis of purified HDM-AEC-EXOs was performed. CNTN1 small interfering RNA was designed to probe its role in airway allergy, and γ-secretase inhibitor was used to determine involvement of the Notch pathway. RESULTS: HDM-AEC-EXOs facilitate the recruitment, proliferation, migration, and activation of monocyte-derived DCs in cell culture and in mice. CNTN1 in exosomes is a critical player in asthma pathology. RNA interference-mediated silencing and pharmaceutical inhibitors characterize Notch2 receptor as necessary for relaying the CNTN1 signal to activate TH2 cell/TH17 cell immune response. Studies of patients with asthma also support existence of the CNTN1-Notch2 axis that has been observed in cell and mouse models. CONCLUSION: This study's findings reveal a novel role for CNTN1 in asthma pathogenesis mediated through exosome secretion, indicating a potential strategy for the treatment of allergic airway inflammation.

ON-bipolar cell gene expression during retinal degeneration: Implications for optogenetic visual restoration.

PURPOSE: Retinal bipolar cells survive even in the later stages of inherited retinal degenerations (IRDs) and so are attractive targets for optogenetic approaches to vision restoration. However, it is not known to what extent the remodelling that these cells undergo during degeneration affects their function. Specifically, it is unclear if they are free from metabolic stress, receptive to adeno-associated viral vectors, suitable for opsin-based optogenetic tools and able to propagate signals by releasing neurotransmitter. METHODS: Fluorescence activated cell sorting (FACS) was performed to isolate labelled bipolar cells from dissociated retinae of litter-mates with or without the IRD mutation Pde6brd1/rd1 selectively expressing an enhanced yellow fluorescent protein (EYFP) as a marker in ON-bipolar cells. Subsequent mRNA extraction allowed Illumina® microarray comparison of gene expression in bipolar cells from degenerate to those of wild type retinae. Changes in four candidate genes were further investigated at the protein level using retinal immunohistochemistry over the course of degeneration. RESULTS: A total of sixty differentially expressed transcripts reached statistical significance: these did not include any genes directly associated with native primary bipolar cell signalling, nor changes consistent with metabolic stress. Four significantly altered genes (Srm2, Slf2, Anxa7 & Cntn1), implicated in synaptic remodelling, neurotransmitter release and viral vector entry had immunohistochemical staining colocalising with ON-bipolar cell markers and varying over the course of degeneration. CONCLUSION: Our findings suggest relatively few gene expression changes in the context of degeneration: that despite remodelling, bipolar cells are likely to remain viable targets for optogenetic vision restoration. In addition, several genes where changes were seen could provide a basis for investigations to enhance the efficacy of optogenetic therapies.

Differential Expression of a Panel of Ten CNTN1-Associated Genes during Prostate Cancer Progression and the Predictive Properties of the Panel Towards Prostate Cancer Relapse.

Contactin 1 (CNTN1) is a new oncogenic protein of prostate cancer (PC); its impact on PC remains incompletely understood. We observed CNTN1 upregulation in LNCaP cell-derived castration-resistant PCs (CRPC) and CNTN1-mediated enhancement of LNCaP cell proliferation. CNTN1 overexpression in LNCaP cells resulted in enrichment of the CREIGHTON_ENDOCRINE_THERAPY_RESISTANCE_3 gene set that facilitates endocrine resistance in breast cancer. The leading-edge (LE) genes (n = 10) of this enrichment consist of four genes with limited knowledge on PC and six genes novel to PC. These LE genes display differential expression during PC initiation, metastatic progression, and CRPC development, and they predict PC relapse following curative therapies at hazard ratio (HR) 2.72, 95% confidence interval (CI) 1.96-3.77, and p = 1.77 × 10-9 in The Cancer Genome Atlas (TCGA) PanCancer cohort (n = 492) and HR 2.72, 95% CI 1.84-4.01, and p = 4.99 × 10-7 in Memorial Sloan Kettering Cancer Center (MSKCC) cohort (n = 140). The LE gene panel classifies high-, moderate-, and low-risk of PC relapse in both cohorts. Additionally, the gene panel robustly predicts poor overall survival in clear cell renal cell carcinoma (ccRCC, p = 1.13 × 10-11), consistent with ccRCC and PC both being urogenital cancers. Collectively, we report multiple CNTN1-related genes relevant to PC and their biomarker values in predicting PC relapse.

Upregulated CNTN1 is associated with lymph node metastasis and poor prognosis of colorectal cancer.

BACKGROUND: Contactin1 (CNTN1), a member of the immunoglobulin superfamily, is known to correlate with tumor development and progression. Although recent studies have found that elevated CNTN1 has been demonstrated in some types of cancers, the expression and prognosis of CNTN1 in colorectal cancer (CRC) are unclear. Here, we aimed to determine the clinicopathological characteristics and prognostic role of CNTN1 in CRC patients. METHODS: The protein expression of CNTN1 in tumor tissues was evaluated by immunohistochemistry. In addition, the mRNA and protein expressions of CNTN1 were examined by qRT-PCR and Western blotting analysis in 40 matched adjacent normal mucosa samples. The relationships of CNTN1 with clinicopathological data and prognosis significance were analyzed. RESULTS: Immunohistochemical consequence suggested that the protein level of CNTN1 was obviously raised in CRC compared with adjacent normal mucosa tissues (56.9% vs 10.3%, P< 0.05). In addition, we detected a significant increase in CNTN1 mRNA and protein levels in CRC tissues compared with the matched adjacent normal mucosa tissues. Moreover, increased CNTN1 exprssion was significantly associated with tumor size, lymph node metastasis (LNM), tumor node-metastasis (TNM) stage and carcino-embryonic antigen (CEA) in clinical analysis. Kaplan-Meier analysis suggested that patients with CNTN1 over-expression showed worse overall survival (OS) (P= 0.001). Multivariate analysis indicated that high CNTN1 expression was an independent predictor for poor OS in CRC patients (P= 0.028). Further analysis revealed that patients with high CNTN1 combined with LNM present accurately predicted poorer outcome. CONCLUSION: Taken together, the findingsindicate that CNTN1 plays a significant role and serve as a potential biomarker for the prediction of adverse prognosis in CRC. Intriguingly, high express of CNTN1 + LNM-present combination may improve the accuracy of prognosis.

Exploring the Role of Contactins across Psychological, Psychiatric and Cardiometabolic Traits within UK Biobank.

Individuals with severe mental illness have an increased risk of cardiometabolic diseases compared to the general population. Shared risk factors and medication effects explain part of this excess risk; however, there is growing evidence to suggest that shared biology (including genetic variation) is likely to contribute to comorbidity between mental and physical illness. Contactins are a family of genes involved in development of the nervous system and implicated, though genome-wide association studies, in a wide range of psychological, psychiatric and cardiometabolic conditions. Contactins are plausible candidates for shared pathology between mental and physical health. We used data from UK Biobank to systematically assess how genetic variation in contactin genes was associated with a wide range of psychological, psychiatric and cardiometabolic conditions. We also investigated whether associations for cardiometabolic and psychological traits represented the same or distinct signals and how the genetic variation might influence the measured traits. We identified: A novel genetic association between variation in CNTN1 and current smoking; two independent signals in CNTN4 for BMI; and demonstrated that associations between CNTN5 and neuroticism were distinct from those between CNTN5 and blood pressure/HbA1c. There was no evidence that the contactin genes contributed to shared aetiology between physical and mental illness.

Contactin 1: An Important and Emerging Oncogenic Protein Promoting Cancer Progression and Metastasis.

Even with recent progress, cancer remains the second leading cause of death, outlining a need to widen the current understanding on oncogenic factors. Accumulating evidence from recent years suggest Contactin 1 (CNTN1)'s possession of multiple oncogenic activities in a variety of cancer types. CNTN1 is a cell adhesion molecule that is dysregulated in many human carcinomas and plays important roles in cancer progression and metastases. Abnormalities in CNTN1 expression associate with cancer progression and poor prognosis. Mechanistically, CNTN1 functions in various signaling pathways frequently altered in cancer, such as the vascular endothelial growth factor C (VEGFC)-VEGF receptor 3 (VEFGR3)/fms-related tyrosine kinase 4 (Flt4) axis, phosphatidylinositol 3-kinase (PI3K)/protein kinase B (AKT), Notch signaling pathway and epithelial-mesenchymal transition (EMT) process. These oncogenic events are resulted via interactions between tumor and stroma, which can be contributed by CNTN1, an adhesion protein. CNTN1 expression in breast cancer correlates with the expression of genes functioning in cancer-stroma interactions and skeletal system development. Evidence supports that CNTN1 promotes cancer-stromal interaction, resulting in activation of a complex network required for cancer progression and metastasis (bone metastasis for breast cancer). CNTN1 inhibitions has been proven to be effective in experimental models to reduce oncogenesis. In this paper, we will review CNTN1's alterations in cancer, its main biochemical mechanisms and interactions with its relevant cancer pathways.

Contactin-1 Is Required for Peripheral Innervation and Immune Homeostasis Within the Intestinal Mucosa.

Neuronal regulation of diverse physiological functions requires complex molecular interactions in innervated tissues to maintain proper organ function. Here we show that loss of the neuronal cell surface adhesion/recognition molecule Contactin-1 (Cntn1) directly impairs intestinal function causing wasting that subsequently results in global immune defects. Loss of Cntn1 results in hematologic alterations and changes in blood metabolites associated with malnourishment. We found thymus and spleen of Cntn1-deficient animals atrophied with severe reductions in lymphocyte populations. Elevated thymic Gilz expression indicated ongoing glucocorticoid signaling in Cntn1-deficient animals, consistent with the malnourishment phenotype. Intestinal Contactin-1 was localized to neurons in the villi and the submucosal/myenteric plexus that innervates smooth muscle. Loss of Cntn1 was associated with reduced intestinal Bdnf and Adrb2, indicating reduced neuromuscular crosstalk. Additionally, loss of Cntn1 resulted in reduced recruitment of CD3+ T cells to villi within the small intestine. Together, these data illustrate the critical role of Contactin-1 function within the gut, and how this is required for normal systemic immune functions.

Two adhesive systems cooperatively regulate axon ensheathment and myelin growth in the CNS.

Central nervous system myelin is a multilayered membrane produced by oligodendrocytes to increase neural processing speed and efficiency, but the molecular mechanisms underlying axonal selection and myelin wrapping are unknown. Here, using combined morphological and molecular analyses in mice and zebrafish, we show that adhesion molecules of the paranodal and the internodal segment work synergistically using overlapping functions to regulate axonal interaction and myelin wrapping. In the absence of these adhesive systems, axonal recognition by myelin is impaired with myelin growing on top of previously myelinated fibers, around neuronal cell bodies and above nodes of Ranvier. In addition, myelin wrapping is disturbed with the leading edge moving away from the axon and in between previously formed layers. These data show how two adhesive systems function together to guide axonal ensheathment and myelin wrapping, and provide a mechanistic understanding of how the spatial organization of myelin is achieved.

Contactin 1 modulates pegylated arginase resistance in small cell lung cancer through induction of epithelial-mesenchymal transition.

Drug resistance is a major hurdle in the treatment of small cell lung cancer (SCLC). Previously we demonstrated the potential anticancer effect of pegylated arginase BCT-100 in SCLC cell lines and xenograft models. To facilitate future clinical application of BCT-100 in SCLC treatment, we elucidated the potential mechanisms that underlie acquired drug resistance to BCT-100. H446 and H526 SCLC cells were serially cultured in stepwise increasing concentrations of BCT-100 until stable BCT-100-resistant cell lines emerged (H446-BR and H526-BR). Compared with parent cells, H446-BR and H526-BR displayed stronger migration ability, anoikis resistance and EMT progression. Gene chip assay was employed to select three potential targets (CDH17, CNTN-1 and IGF2BP1). Silencing CNTN-1 rather than CDH17 or IGF2BP1 in H446-BR and H526-BR cells re-sensitized resistant cells to BCT-100 treatment and attenuated the epithelial-mesenchymal transition (EMT) phenotype. The AKT signaling pathway was activated in H446-BR and H526-BR cells accompanied by EMT progression, and AKT inhibitor LY294002 reversed the EMT progression in resistant cells.

Role of a Contactin multi-molecular complex secreted by oligodendrocytes in nodal protein clustering in the CNS.

The fast and reliable propagation of action potentials along myelinated fibers relies on the clustering of voltage-gated sodium channels at nodes of Ranvier. Axo-glial communication is required for assembly of nodal proteins in the central nervous system, yet the underlying mechanisms remain poorly understood. Oligodendrocytes are known to support node of Ranvier assembly through paranodal junction formation. In addition, the formation of early nodal protein clusters (or prenodes) along axons prior to myelination has been reported, and can be induced by oligodendrocyte conditioned medium (OCM). Our recent work on cultured hippocampal neurons showed that OCM-induced prenodes are associated with an increased conduction velocity (Freeman et al., 2015). We here unravel the nature of the oligodendroglial secreted factors. Mass spectrometry analysis of OCM identified several candidate proteins (i.e., Contactin-1, ChL1, NrCAM, Noelin2, RPTP/Phosphacan, and Tenascin-R). We show that Contactin-1 combined with RPTP/Phosphacan or Tenascin-R induces clusters of nodal proteins along hippocampal GABAergic axons. Furthermore, Contactin-1-immunodepleted OCM or OCM from Cntn1-null mice display significantly reduced clustering activity, that is restored by addition of soluble Contactin-1. Altogether, our results identify Contactin-1 secreted by oligodendrocytes as a novel factor that may influence early steps of nodal sodium channel cluster formation along specific axon populations.

Polyphenol Effects on Splenic Cytokine Response in Post-Weaning Contactin 1-Overexpressing Transgenic Mice.

BACKGROUND: In mice, postnatal immune development has previously been investigated, and evidence of a delayed maturation of the adaptive immune response has been detected. METHODS: In this study, the effects of red grape polyphenol oral administration on the murine immune response were explored using pregnant mice (TAG/F3 transgenic and wild type (wt) mice) as the animal model. The study was performed during pregnancy as well as during lactation until postnatal day 8. Suckling pups from polyphenol-administered dams as well as day 30 post-weaning pups (dietary-administered with polyphenols) were used. Polyphenol effects were evaluated, measuring splenic cytokine secretion. RESULTS: Phorbol myristate acetate-activated splenocytes underwent the highest cytokine production at day 30 in both wt and TAG/F3 mice. In the latter, release of interferon (IFN)-γ and tumor necrosis factor (TNF)-α was found to be higher than in the wt counterpart. In this context, polyphenols exerted modulating activities on day 30 TAG/F3 mice, inducing release of interleukin (IL)-10 in hetero mice while abrogating release of IL-2, IFN-γ, TNF-α, IL-6, and IL-4 in homo and hetero mice. CONCLUSION: Polyphenols are able to prevent the development of an inflammatory/allergic profile in postnatal TAG/F3 mice.

PLP1 and CNTN1 gene variation modulates the microstructure of human white matter in the corpus callosum.

The corpus callosum is the brain's largest commissural fiber tract and is crucial for interhemispheric integration of neural information. Despite the high relevance of the corpus callosum for several cognitive systems, the molecular determinants of callosal microstructure are largely unknown. Recently, it was shown that genetic variations in the myelin-related proteolipid 1 gene PLP1 and the axon guidance related contactin 1 gene CNTN1 were associated with differences in interhemispheric integration at the behavioral level. Here, we used an innovative new diffusion neuroimaging technique called neurite orientation dispersion and density imaging (NODDI) to quantify axonal morphology in subsections of the corpus callosum and link them to genetic variation in PLP1 and CNTN1. In a cohort of 263 healthy human adults, we found that polymorphisms in both PLP1 and CNTN1 were significantly associated with callosal microstructure. Importantly, we found a double dissociation between gene function and neuroimaging variables. Our results suggest that genetic variation in the myelin-related gene PLP1 impacts white matter microstructure in the corpus callosum, possibly by affecting myelin structure. In contrast, genetic variation in the axon guidance related gene CNTN1 impacts axon density in the corpus callosum. These findings suggest that PLP1 and CNTN1 gene variations modulate specific aspects of callosal microstructure that are in line with their gene function.

Identification of CRKII, CFL1, CNTN1, NME2, and TKT as Novel and Frequent T-Cell Targets in Human IDH-Mutant Glioma.

Purpose: Successful immunotherapies for IDHmut gliomas require better knowledge of T-cell target antigens. Here, we elucidated their antigen repertoire recognized by spontaneous T-cell responses using an unbiased proteomic approach.Experimental Design: Protein fractionations of tissue lysates from IDHmut gliomas (n = 4) were performed. Fractions were tested by IFNγ ELISpot assay for recognition through patients' T cells. Proteins of immunogenic fractions were identified by mass spectrometry and validated by in silico-predicted synthetic long peptides in patients of origin, additional IDHmut glioma patients (n = 16), and healthy donors (n = 13). mRNA and protein expression of immunogenic antigens was analyzed in tumor tissues and IDHmut glioma stem-like cells (GSC). HLA-A*02-restricted T-cell epitopes were functionally determined by short peptides and numbers of antigen-specific T cells by HLA-peptide tetramer analysis.Results: A total of 2,897 proteins were identified in immunogenic tumor fractions. Based on a thorough filter process, 79 proteins were selected as potential T-cell antigens. Twenty-six of these were recognized by the patients' T cells, and five of them (CRKII, CFL1, CNTN1, NME2, and TKT) in up to 56% unrelated IDHmut glioma patients. Most immunogenic tumor-associated antigens (TAA) were expressed in IDHmut gliomas and GSCs, while being almost absent in normal brain tissues. Finally, we identified HLA-A*02-restricted epitopes for CRKII, NME2, and TKT that were recognized by up to 2.82% of antigen-specific peripheral cytotoxic T cells in IDHmut glioma patients.Conclusions: By analyzing the repertoire of T-cell target antigens in IDHmut glioma patients, we identified five novel immunogenic TAAs and confirmed their expression on IDHmut tumors and GSCs. Clin Cancer Res; 24(12); 2951-62. ©2018 AACR.

Regulation and dysregulation of axon infrastructure by myelinating glia.

Axon loss and neurodegeneration constitute clinically debilitating sequelae in demyelinating diseases such as multiple sclerosis, but the underlying mechanisms of secondary degeneration are not well understood. Myelinating glia play a fundamental role in promoting the maturation of the axon cytoskeleton, regulating axon trafficking parameters, and imposing architectural rearrangements such as the nodes of Ranvier and their associated molecular domains. In the setting of demyelination, these changes may be reversed or persist as maladaptive features, leading to axon degeneration. In this review, we consider recent insights into axon-glial interactions during development and disease to propose that disruption of the cytoskeleton, nodal architecture, and other components of axon infrastructure is a potential mediator of pathophysiological damage after demyelination.

CNTN-1 Enhances Chemoresistance in Human Lung Adenocarcinoma Through Induction of Epithelial-Mesenchymal Transition by Targeting the PI3K/Akt Pathway.

BACKGROUND/AIMS: Chemoresistance has been a major obstacle to the effective treatment of lung cancer. Previously, we found that contactin-1 (CNTN-1) is related to cisplatin resistance in lung adenocarcinoma. Here, we aimed to investigate the underlying mechanism behind the role of CNTN-1 in cisplatin resistance in lung adenocarcinoma. METHODS: EMT-associated phenotypes, including alterations in cellular morphology and marker (E-cadherin, N-cadherin and Vimentin) expression, were compared between A549 cells and A549/DDP cells (a cisplatin-resistant cell line of lung adenocarcinoma with abnormal CNTN-1 expression) by using real-time time PCR and Western blotting. Other methods, including CNTN-1 overexpression in A549 cells and CNTN-1 knockdown in A549/DDP cells, were also used to investigate the role of CNTN-1 in mediating the EMT phenotype and thr resulting cisplatin resistance and malignant progression of cancer cells in vitro and in vivo. RESULTS: A549/DDP cells exhibited an EMT phenotype and aggravated malignant behaviors. CNTN-1 knockdown in A549/DDP cells partly reversed the EMT phenotype, increased drug sensitivity, and attenuated the malignant progression whereas CNTN-1 overexpression in A549 cells resulted in the opposite trend. Furthermore, the PI3K/Akt pathway was involved in the effects of CNTN-1 on EMT progression in A549/DDP cells, verified by the xenograft mouse model. CONCLUSION: CNTN-1 promotes cisplatin resistance in human cisplatin-resistant lung adenocarcinoma through inducing the EMT process by activating the PI3K/Akt signaling pathway. CNTN-1 may be a potential therapeutic target to reverse chemoresistance in cisplatin-resistant lung adenocarcinoma.

Medaka and zebrafish contactin1 mutants as a model for understanding neural circuits for motor coordination.

A spontaneous medaka ro mutant shows abnormal wobbling and rolling swimming behaviors. By positional cloning, we mapped the ro locus to a region containing the gene encoding Contactin1b (Cntn1b), which is an immunoglobulin (Ig)-superfamily domain-containing membrane-anchored protein. The ro mutant had a deletion in the cntn1b gene that introduced a premature stop codon. Furthermore, cntn1b mutants generated by the CRISPR/Cas9 system and trans-heterozygotes of the CRISPR mutant allele and ro had abnormal swimming behavior, indicating that the cntn1b gene was responsible for the ro-mutant phenotype. We also established zebrafish cntn1a and cntn1b mutants by transcription activator-like effector nucleases (TALENs). Zebrafish cntn1b but not cntn1a mutants showed abnormal swimming behaviors similar to those in the ro mutant, suggesting that Cntn1b plays a conserved role in the formation or function of the neural circuits that control swimming in teleosts. Although Cntn1-deficient mice have abnormal cerebellar neural circuitry, there was no apparent histological abnormality in the cerebellum of medaka or zebrafish cntn1b mutants. The medaka cntn1b mutants had defective optokinetic response (OKR) adaptation and abnormal rheotaxis (body positioning relative to water flow). Medaka and zebrafish cntn1b mutants are effective models for studying the neural circuits involved in motor learning and motor coordination.

Role of the adhesion molecule F3/Contactin in synaptic plasticity and memory.

Cell adhesion molecules (CAMs) have a pivotal role in building and maintaining synaptic structures during brain development participating in axonal elongation and pathfinding, glial guidance of neuronal migration, as well as myelination. CAMs expression persists in the adult brain particularly in structures undergoing postnatal neurogenesis and involved in synaptic plasticity and memory as the hippocampus. Among the neural CAMs, we have recently focused on F3/Contactin, a glycosylphosphatidyl inositol-anchored glycoprotein belonging to the immunoglobulin superfamily, involved in neuronal development, synaptic maintenance and organization of neuronal networks. Here, we discuss our recent data suggesting that F3/Contactin exerts a role in hippocampal synaptic plasticity and memory in adult and aged mice. In particular, we have studied long-term potentiation (LTP), spatial and object recognition memory, and phosphorylation of the transcription factor cAMP-Responsive-Element Binding protein (CREB) in a transgenic mouse model of F3/Contactin overexpression. We also investigated whether F3/Contactin might influence neuronal apoptosis and the production of amyloid-beta peptide (Aß), known to be one of the main pathogenetic hallmarks of Alzheimer's disease (AD). In conclusion, a further understanding of F3/Contactin role in synaptic plasticity and memory might have interesting clinical outcomes in cognitive disorders, such as aging and AD, offering innovative therapeutic opportunities.

Complement deposition induced by binding of anti-contactin-1 auto-antibodies is modified by immunoglobulins.

Inflammatory neuropathies associated with auto-antibodies against paranodal proteins like contactin-1 are reported to respond poorly to treatment with intravenous immunoglobulins (IVIG). A reason might be that IVIG interacts with the complement pathway and these auto-antibodies often belong to the IgG4 subclass that does not activate complement. However, some patients do show a response to IVIG, especially at the beginning of the disease. This corresponds with the finding of coexisting IgG subclasses IgG1, IgG2 and IgG3. We therefore aimed to investigate complement deposition and activation by samples of three patients with anti-contactin-1 IgG auto-antibodies of different subclasses as a potential predictor for response to IVIG. Complement deposition and activation was measured by cell binding and ELISA based assays, and the effect of IVIG on complement deposition was assessed by addition of different concentrations of IVIG. Binding of anti-contactin-1 auto-antibodies of all three patients induced complement deposition and activation with the strongest effect shown by the serum of a patient with predominance of IgG3 auto-antibodies. IVIG led to a reduction of complement deposition in a dose-dependent manner, but did not reduce binding of auto-antibodies to contactin-1. We conclude that complement deposition may contribute to the pathophysiology of anti-contactin-1 associated neuropathy, particularly in patients with predominance of the IgG3 subclass. The proportion of different auto-antibody subclasses may be a predictor for the response to IVIG in patients with auto-antibodies against paranodal proteins.

Myelin Genes and the Corpus Callosum: Proteolipid Protein 1 (PLP1) and Contactin 1 (CNTN1) Gene Variation Modulates Interhemispheric Integration.

Interhemispheric communication during demanding cognitive tasks shows pronounced interindividual variation. Differences in interhemispheric transfer time are constituted by the relative composition of slow and fast fibers. The speed of axonal conduction depends on the diameter of the axon and its myelination. To understand the possible genetic impact of myelin genes on performance in the Banich-Belger Task, a widely used paradigm to assess interhemispheric integration, 453 healthy adults were genotyped for 18 single nucleotide polymorphisms (SNPs) in six myelin-related candidate genes. We replicated the typical pattern of results in the Banich-Belger Task, supporting the idea that performance on cognitively demanding tasks is enhanced when cognitive processing is distributed across the two hemispheres. Moreover, allelic variations in the proteolipid protein 1 gene PLP1 and the contactin 1 gene CNTN1 correlated with the extent to which individual performance is enhanced by interhemispheric integration. Variation in myelin genes possibly affects the microstructure of the corpus callosum by altering oligodendrocyte structure. Therefore, these results provide a foundation for understanding how genetics plays a role in modulating the efficacy of transcallosal transmission.