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Molecular Brain Apr 2020The receptor deleted in colorectal cancer (DCC) and its ligand netrin-1 are essential for axon guidance during development and are expressed by neurons in the mature...
The receptor deleted in colorectal cancer (DCC) and its ligand netrin-1 are essential for axon guidance during development and are expressed by neurons in the mature brain. Netrin-1 recruits GluA1-containing α-amino-3-hydroxy-5-methyl-4-isoxazolepropionic acid receptors (AMPARs) and is critical for long-term potentiation (LTP) at CA3-CA1 hippocampal Schaffer collateral synapses, while conditional DCC deletion from glutamatergic neurons impairs hippocampal-dependent spatial memory and severely disrupts LTP induction. DCC co-fractionates with the detergent-resistant component of postsynaptic density, yet is enriched in axonal growth cones that differentiate into presynaptic terminals during development. Specific presynaptic and postsynaptic contributions of DCC to the function of mature neural circuits have yet to be identified. Employing hippocampal subregion-specific conditional deletion of DCC, we show that DCC loss from CA1 hippocampal pyramidal neurons resulted in deficits in spatial memory, increased resting membrane potential, abnormal dendritic spine morphology, weaker spontaneous excitatory postsynaptic activity, and reduced levels of postsynaptic adaptor and signaling proteins; however, the capacity to induce LTP remained intact. In contrast, deletion of DCC from CA3 neurons did not induce detectable changes in the intrinsic electrophysiological properties of CA1 pyramidal neurons, but impaired performance on the novel object place recognition task as well as compromised excitatory synaptic transmission and LTP at Schaffer collateral synapses. Together, these findings reveal specific pre- and post-synaptic contributions of DCC to hippocampal synaptic plasticity underlying spatial memory.
Topics: Aging; Animals; CA1 Region, Hippocampal; CA3 Region, Hippocampal; DCC Receptor; Dendritic Spines; Gene Deletion; Glutamic Acid; Hippocampus; Memory Consolidation; Mice, Inbred C57BL; Neurons; Pyramidal Cells; Spatial Memory; Synapses
PubMed: 32264905
DOI: 10.1186/s13041-020-00597-2 -
Cancer Research Feb 2020Deleted in colorectal cancer (DCC), the receptor for the multifunctional cue netrin-1, acts as a tumor suppressor in intestinal cancer and lung metastasis by triggering... (Observational Study)
Observational Study
Deleted in colorectal cancer (DCC), the receptor for the multifunctional cue netrin-1, acts as a tumor suppressor in intestinal cancer and lung metastasis by triggering cancer cell death when netrin-1 is lowly expressed. Recent genomic data highlighted that DCC is the third most frequently mutated gene in melanoma; we therefore investigated whether DCC could act as a melanoma tumor suppressor. Reexpressing DCC in human melanoma cell lines promoted tumor cell death and tumor growth inhibition in xenograft mouse models. Genetic silencing of DCC prodeath activity in a BRAF mouse model increased the proportion of mice with melanoma, further supporting that DCC is a melanoma tumor suppressor. Netrin-1 expression was elevated in melanoma compared with benign melanocytic lesions. Upregulation of netrin-1 in the skin cells of a BRAF-mutated murine model reduced cancer cell death and promoted melanoma progression. Therapeutic antibody blockade of netrin-1 combined with dacarbazine increased overall survival in several mouse melanoma models. Together, these data support that interfering with netrin-1 could be a viable therapeutic approach in patients with netrin-1-expressing melanoma. SIGNIFICANCE: Netrin-1 and its receptor DCC regulate melanoma progression, suggesting therapeutic targeting of this signaling axis as a viable option for melanoma treatment.
Topics: Animals; Antineoplastic Agents; Cell Line, Tumor; DCC Receptor; Disease Progression; Female; Follow-Up Studies; Humans; Melanoma; Mice; Mice, Transgenic; Netrin-1; Proto-Oncogene Proteins B-raf; Skin; Skin Neoplasms; Tumor Suppressor Proteins; Up-Regulation; Xenograft Model Antitumor Assays
PubMed: 31806640
DOI: 10.1158/0008-5472.CAN-18-1590 -
Respiratory Research Nov 2020There is evidence that bacterial colonisation in chronic obstructive pulmonary disease (COPD) is associated with increased neutrophilic airway inflammation. This study...
BACKGROUND
There is evidence that bacterial colonisation in chronic obstructive pulmonary disease (COPD) is associated with increased neutrophilic airway inflammation. This study tested the hypothesis that different bacterial phyla and species cause different inflammatory profiles in COPD patients.
METHODS
Sputum was analysed by quantitative polymerase chain reaction (qPCR) to quantify bacterial load and 16S rRNA gene sequencing to identify taxonomic composition. Sputum differential cell counts (DCC) and blood DCC were obtained at baseline and 6 months. Patients were categorised into five groups based on bacterial load defined by genome copies/ml of ≥ 1 × 10, no colonisation and colonisation by Haemophilus influenzae (H. influenzae), Moraxella catarrhalis (M. catarrhalis), Streptococcus pneumoniae (S. pneumoniae), or > 1 potentially pathogenic microorganism (PPM).
RESULTS
We observed an increase in sputum neutrophil (%), blood neutrophil (%) and neutrophil-lymphocyte ratio (NLR) in patients colonised with H. influenzae (82.6, 67.1, and 3.29 respectively) compared to those without PPM colonisation at baseline (69.5, 63.51 and 2.56 respectively) (p < 0.05 for all analyses), with similar findings at 6 months. The bacterial load of H. influenzae and Haemophilus determined by qPCR and 16s rRNA gene sequencing respectively, and sputum neutrophil % were positively correlated between baseline and 6 months visits (p < 0.0001, 0.0150 and 0.0002 with r = 0.53, 0.33 and 0.44 respectively).
CONCLUSIONS
These results demonstrate a subgroup of COPD patients with persistent H. influenzae colonisation that is associated with increased airway and systemic neutrophilic airway inflammation, and less eosinophilic airway inflammation.
Topics: Aged; Bacterial Load; Cell Count; Cohort Studies; Female; Haemophilus influenzae; Humans; Male; Middle Aged; Neutrophils; Pulmonary Disease, Chronic Obstructive; Sputum
PubMed: 33131502
DOI: 10.1186/s12931-020-01552-4 -
Cytogenetic and Genome Research 2020DCC netrin 1 receptor (DCC) affects the structure and function of the dopamine circuitry, which in turn affects the susceptibility to developing addiction. In a previous...
DCC netrin 1 receptor (DCC) affects the structure and function of the dopamine circuitry, which in turn affects the susceptibility to developing addiction. In a previous study, we found that single nucleotide polymorphism (SNP) rs12607853 in the 3' untranslated region (3'-UTR) of DCC was significantly associated with heroin addiction. In the current study, we first used bioinformatics prediction to identify the DCC rs12607853 C allele as a potential hsa-miR-422a and hsa-miR-378c target site. We then used vector construction and dual-luciferase reporter assays to investigate the targeting relationship of DCC rs12607853 with hsa-miR-422a and hsa-miR-378c. The dual-luciferase reporter gene assay confirmed that the C allele of rs12607853 in combination with hsa-miR-422a led to repressed dual-luciferase gene expression. Moreover, gene expression assays disclosed that hsa-miR-422a inhibited DCC expression at both the mRNA and protein levels. We also found that morphine inhibited the expression of hsa-miR-422a but increased the expression of DCC mRNA, and this change in the expression of hsa-miR-422a could not be reversed by naloxone, which suggested that the role of DCC in opioid addiction might be regulated by hsa-miR-422a. In summary, this study improves our understanding of the role of hsa-miR-422a and identifies the genetic basis of rs12607853, which might contribute to the discovery of new biomarkers or therapeutic targets for opioid addiction.
Topics: 3' Untranslated Regions; Cell Line, Tumor; Computational Biology; DCC Receptor; Down-Regulation; HEK293 Cells; Heroin Dependence; Humans; MicroRNAs; Morphine; Naloxone; Polymorphism, Single Nucleotide
PubMed: 32092754
DOI: 10.1159/000506031 -
Developmental Medicine and Child... Jun 2020Pathogenic variants in the gene encoding deleted in colorectal cancer (DCC) are the first genetic cause of isolated agenesis of the corpus callosum (ACC). Here we...
Pathogenic variants in the gene encoding deleted in colorectal cancer (DCC) are the first genetic cause of isolated agenesis of the corpus callosum (ACC). Here we present the detailed neurological, brain magnetic resonance imaging (MRI), and neuropsychological characteristics of 12 individuals from three families with pathogenic variants in DCC (aged 8-50y), who showed ACC and mirror movements (n=5), mirror movements only (n=2), ACC only (n=3), or neither ACC nor mirror movements (n=2). There was heterogeneity in the neurological and neuroimaging features on brain MRI, and performance across neuropsychological domains ranged from extremely low (impaired) to within normal limits (average). Our findings show that ACC and/or mirror movements are associated with low functioning in select neuropsychological domains and a DCC pathogenic variant alone is not sufficient to explain the disability. WHAT THIS PAPER ADDS: Neuropsychological impairment severity is related to presence of mirror movements and/or agenesis of the corpus callosum. A DCC pathogenic variant in isolation is associated with the best prognosis.
Topics: Adolescent; Adult; Agenesis of Corpus Callosum; Child; Cohort Studies; DCC Receptor; Female; Humans; Magnetic Resonance Imaging; Male; Middle Aged; Movement Disorders; Mutation; Neuropsychological Tests; Prognosis; Young Adult
PubMed: 32060908
DOI: 10.1111/dmcn.14486 -
Journal of Visualized Experiments : JoVE Nov 2019Circular RNAs (circRNAs) are a class of non-coding RNAs involved in functions including micro-RNA (miRNA) regulation, mediation of protein-protein interactions, and...
Circular RNAs (circRNAs) are a class of non-coding RNAs involved in functions including micro-RNA (miRNA) regulation, mediation of protein-protein interactions, and regulation of parental gene transcription. In classical next generation RNA sequencing (RNA-seq), circRNAs are typically overlooked as a result of poly-A selection during construction of mRNA libraries, or are found at very low abundance, and are therefore difficult to isolate and detect. Here, a circRNA library construction protocol was optimized by comparing library preparation kits, pre-treatment options and various total RNA input amounts. Two commercially available whole transcriptome library preparation kits, with and without RNase R pre-treatment, and using variable amounts of total RNA input (1 to 4 µg), were tested. Lastly, multiple tissue types; including liver, lung, lymph node, and pancreas; as well as multiple brain regions; including the cerebellum, inferior parietal lobe, middle temporal gyrus, occipital cortex, and superior frontal gyrus; were compared to evaluate circRNA abundance across tissue types. Analysis of the generated RNA-seq data using six different circRNA detection tools (find_circ, CIRI, Mapsplice, KNIFE, DCC, and CIRCexplorer) revealed that a stranded total RNA library preparation kit with RNase R pre-treatment and 4 µg RNA input is the optimal method for identifying the highest relative number of circRNAs. Consistent with previous findings, the highest enrichment of circRNAs was observed in brain tissues compared to other tissue types.
Topics: Base Sequence; Brain; Gene Library; High-Throughput Nucleotide Sequencing; Humans; MicroRNAs; RNA, Circular; RNA, Messenger; Sequence Analysis, RNA; Transcriptome; Exome Sequencing
PubMed: 31789321
DOI: 10.3791/59981 -
Cell Reports May 2023Dynamic and coordinated axonal responses to changing environments are critical for establishing neural connections. As commissural axons migrate across the CNS midline,...
Dynamic and coordinated axonal responses to changing environments are critical for establishing neural connections. As commissural axons migrate across the CNS midline, they are suggested to switch from being attracted to being repelled in order to approach and to subsequently leave the midline. A molecular mechanism that is hypothesized to underlie this switch in axonal responses is the silencing of Netrin1/Deleted in Colorectal Carcinoma (DCC)-mediated attraction by the repulsive SLIT/ROBO1 signaling. Using in vivo approaches including CRISPR-Cas9-engineered mouse models of distinct Dcc splice isoforms, we show here that commissural axons maintain responsiveness to both Netrin and SLIT during midline crossing, although likely at quantitatively different levels. In addition, full-length DCC in collaboration with ROBO3 can antagonize ROBO1 repulsion in vivo. We propose that commissural axons integrate and balance the opposing DCC and Roundabout (ROBO) signaling to ensure proper guidance decisions during midline entry and exit.
Topics: Animals; Mice; Nerve Tissue Proteins; Receptors, Immunologic; Axon Guidance; Axons; Netrins; Gene Expression Regulation, Developmental; DCC Receptor
PubMed: 37149867
DOI: 10.1016/j.celrep.2023.112455 -
Whole-Exome Sequencing Identifies Pathogenic Germline Variants in Patients with Lynch-Like Syndrome.Cancers Aug 2022Lynch syndrome (LS) is the most common hereditary colorectal cancer (CRC) syndrome, characterized by germline pathogenic variants in mismatch repair (MMR)-related genes...
Lynch syndrome (LS) is the most common hereditary colorectal cancer (CRC) syndrome, characterized by germline pathogenic variants in mismatch repair (MMR)-related genes that lead to microsatellite instability. Patients who meet the clinical criteria for LS and MMR deficiency and without any identified germline pathogenic variants are frequently considered to have Lynch-like syndrome (LLS). These patients have a higher risk of CRC and extracolonic tumors, and little is known about their underlying genetic causes. We investigated the germline spectrum of LLS patients through whole-exome sequencing (WES). A total of 20 unrelated patients with MMR deficiency who met the clinical criteria for LS and had no germline variant were subjected to germline WES. Variant classification was performed according to the American College of Medical Genetics and Genomics (ACMG) criteria. Pathogenic/likely pathogenic variants were identified in 35% of patients in known cancer genes such as and . Besides this, rare and potentially pathogenic variants were identified in the DNA repair gene and other cancer-related genes such as , , and . Our study demonstrates the germline mutational status of LLS patients, a population at high risk of colorectal cancer.
PubMed: 36077770
DOI: 10.3390/cancers14174233 -
Journal of Psychiatry & Neuroscience :... Nov 2020Genetic variation in the guidance cue gene is linked to psychopathologies involving dysfunction in the prefrontal cortex. We created an expression-based polygenic risk...
BACKGROUND
Genetic variation in the guidance cue gene is linked to psychopathologies involving dysfunction in the prefrontal cortex. We created an expression-based polygenic risk score (ePRS) based on the coexpression gene network in the prefrontal cortex, hypothesizing that it would be associated with individual differences in total brain volume.
METHODS
We filtered single nucleotide polymorphisms (SNPs) from genes coexpressed with in the prefrontal cortex obtained from an adult postmortem donors database (BrainEAC) for genes enriched in children 1.5 to 11 years old (BrainSpan). The SNPs were weighted by their effect size in predicting gene expression in the prefrontal cortex, multiplied by their allele number based on an individual's genotype data, and then summarized into an ePRS. We evaluated associations between the ePRS and total brain volume in children in 2 community-based cohorts: the Maternal Adversity, Vulnerability and Neurodevelopment (MAVAN) and University of California, Irvine (UCI) projects. For comparison, we calculated a conventional PRS based on a genome-wide association study of total brain volume.
RESULTS
Higher ePRS was associated with higher total brain volume in children 8 to 10 years old (β = 0.212, = 0.043; = 88). The conventional PRS at several different thresholds did not predict total brain volume in this cohort. A replication analysis in an independent cohort of newborns from the UCI study showed an association between the ePRS and newborn total brain volume (β = 0.101, = 0.048; = 80). The genes included in the ePRS demonstrated high levels of coexpression throughout the lifespan and are primarily involved in regulating cellular function.
LIMITATIONS
The relatively small sample size and age differences between the main and replication cohorts were limitations.
CONCLUSION
Our findings suggest that the coexpression network in the prefrontal cortex is critically involved in whole brain development during the first decade of life. Genes comprising the ePRS are involved in gene translation control and cell adhesion, and their expression in the prefrontal cortex at different stages of life provides a snapshot of their dynamic recruitment.
Topics: Adult; Brain; Child; Child, Preschool; Cohort Studies; DCC Receptor; Female; Gene Regulatory Networks; Genome-Wide Association Study; Humans; Infant; Infant, Newborn; Male; Multifactorial Inheritance; Polymorphism, Single Nucleotide; Prefrontal Cortex
PubMed: 33206040
DOI: 10.1503/jpn.200081 -
Cancer Cell International 2020Due to the high morbidity and poor clinical outcomes, early predictive and prognostic biomarker identification is desiderated in colorectal cancer (CRC). As a homologue...
BACKGROUND
Due to the high morbidity and poor clinical outcomes, early predictive and prognostic biomarker identification is desiderated in colorectal cancer (CRC). As a homologue of the Deleted in Colorectal Cancer (DCC) gene, the role of Neogenin-1 (NEO1) in CRC remained unveiled. This study was designed to probe into the effects and potential function of NEO1 in CRC.
METHODS
Online databases, Gene Set Enrichment Analysis (GSEA), quantitative real-time PCR and western blotting were used to evaluate NEO1 expression in colorectal cancer tissues. Survival analysis was performed to predict the prognosis of CRC patients based on NEO1 expression level. Then, cell proliferation was detected by colony formation and Cell Counting Kit 8 (CCK-8) assays. CRC cell migration and invasion were examined by transwell assays. Finally, we utilized the Gene Set Variation Analysis (GSVA) and GSEA to dig the potential mechanisms of NEO1 in CRC.
RESULTS
Oncomine database and The Cancer Genome Atlas (TCGA) database showed that NEO1 was down-regulated in CRC. Further results validated that NEO1 mRNA and protein expression were both significantly lower in CRC tumor tissues than in the adjacent tissues in our clinical samples. NEO1 expression was decreased with the progression of CRC. Survival and other clinical characteristic analyses exhibited that low NEO1 expression was related with poor prognosis. A gain-of-function study showed that overexpression of NEO1 restrained proliferation, migration and invasion of CRC cells while a loss-of-function showed the opposite effects. Finally, functional pathway enrichment analysis revealed that NEO1 low expression samples were enriched in inflammation-related signaling pathways, EMT and angiogenesis.
CONCLUSION
A tumor suppressor gene NEO1 was identified and verified to be correlated with the prognosis and progression of CRC, which could serve as a prognostic biomarker for CRC patients.
PubMed: 33088218
DOI: 10.1186/s12935-020-01604-1