CHL1 depletion affects dopamine receptor D2-dependent modulation of mouse behavior

Introduction

The dopaminergic system plays a key role in the appropriate functioning of the central nervous system, where it is essential for emotional balance, arousal, reward, and motor control. The cell adhesion molecule close homolog of L1 (CHL1) contributes to dopaminergic system development, and CHL1 and the dopamine receptor D2 (D2R) are associated with mental disorders like schizophrenia, addiction, autism spectrum disorder and depression.

Methods

Here, we investigated how the interplay between CHL1 and D2R affects the behavior of young adult male and female wild-type (CHL+/+) and CHL1-deficient (CHL1-/-) mice, when D2R agonist quinpirole and antagonist sulpiride are applied.

Results

Low doses of quinpirole (0.02 mg/kg body weight) induced hypolocomotion of CHL1+/+ and CHL1-/- males and females, but led to a delayed response in CHL1-/- mice. Sulpiride (1 mg/kg body weight) affected locomotion of CHL1-/- females and social interaction of CHL1+/+ females as well as social interactions of CHL1-/- and CHL1+/+ males. Quinpirole increased novelty-seeking behavior of CHL1-/- males compared to CHL1+/+ males. Vehicle-treated CHL1-/- males and females showed enhanced working memory and reduced stress-related behavior.

Discussion

We propose that CHL1 regulates D2R-dependent functions in vivo. Deficiency of CHL1 leads to abnormal locomotor activity and emotionality, and to sex-dependent behavioral differences.

Brain-Derived Neurotrophic Factor Val66Met Genotype Modulates Latent Inhibition: Relevance for Schizophrenia

BACKGROUND AND HYPOTHESIS

Latent inhibition (LI) is a measure of selective attention and learning relevant to Schizophrenia (SZ), with 2 abnormality poles: Disrupted LI in acute SZ, thought to underlie positive symptoms, and persistent LI (PLI) in schizotypy and chronic SZ under conditions where normal participants fail to show LI. We hypothesized that Brain-Derived Neurotrophic Factor (BDNF)-Met genotype shifts LI toward the PLI pole.

STUDY DESIGN

We investigated the role of BDNF-Val66Met polymorphism and neural activation in regions involved in LI in mice, and the interaction between the BDNF and CHL1, a gene associated with SZ.

STUDY RESULTS

No LI differences occurred between BDNF-wild-type (WT) (Val/Val) and knock-in (KI) (Met/Met) mice after weak conditioning. Chronic stress or stronger conditioning disrupted LI in WT but not KI mice. Behavior correlated with activation in infralimbic and orbitofrontal cortices, and nucleus accumbens. Examination of LI in CHL1-KO mice revealed no LI with no Met alleles (BDNF-WTs), PLI in CHL1-WT mice with 1 Met allele (BDNF-HETs), and PLI in both CHL1-WTs and CHL1-KOs with 2 Met alleles (BDNF-KIs), suggesting a shift to LI persistence with the number of BDNF-Met alleles in the CHL1 model of acute SZ.

CONCLUSIONS

Results support a role for BDNF polymorphisms in gene-gene and gene-environment interactions relevant to SZ. BDNF-Met allele may reduce expression of some acute SZ symptoms, and may increase expression of negative symptoms in individuals with chronic SZ. Evaluation of (screening for) SZ phenotypes associated with mutations at a particular locus (eg, CHL1), may be masked by strong effects at different loci (eg, BDNF).

The cohesin complex of yeasts: sister chromatid cohesion and beyond

Each time a cell divides, it needs to duplicate the genome and then separate the two copies. In eukaryotes, which usually have more than one linear chromosome, this entails tethering the two newly replicated DNA molecules, a phenomenon known as sister chromatid cohesion (SCC). Cohesion ensures proper chromosome segregation to separate poles during mitosis. SCC is achieved by the presence of the cohesin complex. Besides its canonical function, cohesin is essential for chromosome organization and DNA damage repair. Surprisingly, yeast cohesin is loaded in G1 before DNA replication starts but only acquires its binding activity during DNA replication. Work in microorganisms, such as Saccharomyces cerevisiae and Schizosaccharomyces pombe has greatly contributed to the understanding of cohesin composition and functions. In the last few years, much progress has been made in elucidating the role of cohesin in chromosome organization and compaction. Here, we discuss the different functions of cohesin to ensure faithful chromosome segregation and genome stability during the mitotic cell division in yeast. We describe what is known about its composition and how DNA replication is coupled with SCC establishment. We also discuss current models for the role of cohesin in chromatin loop extrusion and delineate unanswered questions about the activity of this important, conserved complex.

Interplay in neural functions of cell adhesion molecule close homolog of L1 (CHL1) and Programmed Cell Death 6 (PDCD6)

Close homolog of L1 (CHL1) is a cell adhesion molecule of the immunoglobulin superfamily. It promotes neuritogenesis and survival of neurons in vitro. In vivo, CHL1 promotes nervous system development, regeneration after trauma, and synaptic function and plasticity. We identified programmed cell death 6 (PDCD6) as a novel binding partner of the CHL1 intracellular domain (CHL1-ICD). Co-immunoprecipitation, pull-down assay with CHL1-ICD, and proximity ligation in cerebellum and pons of 3-day-old and 6-month-old mice, as well as in cultured cerebellar granule neurons and cortical astrocytes indicate an association between PDCD6 and CHL1. The Ca2+-chelator BAPTA-AM inhibited the association between CHL1 and PDCD6. The treatment of cerebellar granule neurons with a cell-penetrating peptide comprising the cell surface proximal 30 N-terminal amino acids of CHL1-ICD inhibited the association between CHL1 and PDCD6 and PDCD6- and CHL1-triggered neuronal survival. These results suggest that PDCD6 contributes to CHL1 functions in the nervous system.

Cell adhesion molecule L1 like plays a role in the pathogenesis of idiopathic hypogonadotropic hypogonadism

PURPOSE

The pathogenesis of idiopathic hypogonadotropic hypogonadism (IHH) is genetically complex. The aims of this study were to investigate the genetic profile and clinical manifestation of IHH in a Chinese pedigree and to discover new IHH-associated genes.

METHODS

The first step was to follow up the clinical phenotype and therapeutic outcomes of the pedigree in university hospital. The second step was that mutation screening was performed in this pedigree and 100 healthy controls. The third step was to further verify the pathogenicity of the discovered rare sequencing variant (RSV) by functional experiments. Whole exome sequencing, Sanger sequencing, testicular volume (TV), semen analysis, assessment of cell migration and necroptosis were performed.

RESULTS

One heterozygous RSV (p.G517E) in CHL1 was identified in two male IHH patients and their mother in the pedigree, but not in healthy controls. All the three individuals exhibited olfactory impairment. hCG/hMG treatment significantly improved TV, serum testosterone and/or semen parameters of the two male patients. Functional analysis indicated that CHL1 significantly regulated GnRH neuronal cell line (GN11 cells) migration and necroptosis, with alteration of ERK1/2 activation, calcium loading, and transcription of RIPK3 and MLKL. However, the above processes were negatively influenced by the CHL1 RSV.

CONCLUSIONS

Our study reports the genetic relevance of CHL1 in IHH, and characterizes the phenotypic and therapeutic profiles in patients carrying the CHL1 RSV. CHL1 may act as a new IHH-associated gene, and should be taken into consideration in future investigations for this field.

New BACE1 Chimeric Peptide Inhibitors Selectively Prevent AβPP-β Cleavage Decreasing Amyloid-β Production and Accumulation in Alzheimer's Disease Models

BACKGROUND

A disease-modifying therapy for Alzheimer's disease (AD) is still an unmet clinical need. The formation of amyloid-β (Aβ) requires the initial cleavage of the amyloid-β protein precursor (AβPP) by BACE1 (beta-site AβPP cleaving enzyme 1), which is a prime therapeutic target for AD.

OBJECTIVE

We aimed to design and develop a selective BACE1 inhibitor suitable to AD treatment.

METHODS

The new BACE1 inhibitors consist on a chimeric peptide including a sequence related to the human Swedish mutant form of AβPP (AβPPswe) conjugated with the TAT carrier that facilitates cell membrane permeation and the crossing of the blood-brain barrier. Additionally to the chimeric peptide in the L-form, we developed a D-retroinverso chimeric peptide. The latter strategy, never used with BACE1 inhibitors, is considered to favor a significantly higher half-life and lower immunogenicity.

RESULTS

We found that both chimeric peptides inhibit recombinant BACE1 activity and decrease Aβ40/42 production in Neuro-2a (N2A) cells expressing AβPPswe without inducing cytotoxicity. The intraperitoneal administration of these peptides to 3xTg-AD mice decreased plasma and brain Aβ40/42 levels, as well as brain soluble AβPPβ production. Also, a reduction of insoluble Aβ was observed in the brain after chronic treatment. Noteworthy, the chimeric peptides selectively inhibited the AβPP-β cleavage relatively to the proteolysis of other BACE1 substrates such as close homologue of L1 (CHL1) and seizure-related gene 6 (SEZ6).

CONCLUSIONS

Overall these new BACE1 chimeric peptideshold promising potential as a selective disease-modifying therapy for AD.

CHL1 deletion is associated with cognitive and language disabilities - Case report and review of literature

Background

There is a small, but growing number of reports of pediatric patients with terminal deletions at 3p26.3 involving only the cell adhesion molecule L1‐like (CHL1) gene that has been found to have language delays and intellectual disability. Here we report a one month of age patient who developed seizures and tone abnormalities, with persistent and prominent gross and fine motor delays. The patient has microcephaly and deficits in language and cognitive delays, similar to what has been seen in previous case reports.

Methods

Chromosome and microarray comparative genomic hybridization (aCGH) analysis was performed to identify clinically significant copy number variants (CNVs). In addition, Fluorescent in‐situ hybridization (FISH) was performed to confirm the aCGH findings.

Results

Chromosome analysis revealed an apparently normal (46,XX) female karyotype. Microarray CGH analysis revealed a 639 kb loss at 3p26.3 from 62199 to 701052 base pairs encompassing the whole CHL1 gene that was confirmed by FISH. Parental follow‐up revealed the deletion as maternal in origin.

Conclusion

This case report adds to the limited body of literature that exists on this terminal deletion at 3p26.3 that involves CHL1 gene, and supports prior proposals of an emerging CHL1 microdeletion syndrome that results in language and cognitive delays. Further studies are needed to understand the degree of phenotypic heterogeneity associated with CHL1 gene deletion and whether the size of the deletion or presence of additional copy number variants (CNVs) which were seen in other case reports help predict the expected phenotype for a patient.

Close Homolog of L1 Deficiency Exacerbated Intestinal Epithelial Barrier Function in Mouse Model of Dextran Sulfate Sodium-Induced Colitis

The cell adhesion molecule CHL1, which belongs to the immunoglobulin superfamily, functions in a variety of physiological and pathological processes, including neural development, tissue injury, and repair. We previously found that the loss of CHL1 exacerbated the dextran sulfate sodium (DSS)-induced colitis in mice. In the present study, we further addressed the role of CHL1 in mouse model of DSS-induced colitis and its’ potential mechanism. Colon tissues were collected from CHL1^+/+, CHL1^+/−, and CHL1^−/− mice after DSS induction to investigate the effects of CHL1 on the development of colitis. The data showed that CHL1 was expressed in intestine tissue, and expression of CHL1 was increased by DSS-induced inflammation. CHL1 deficiency induced more pronounced colitis features, exacerbated inflammation, and damage to colonic tissues in DSS-induced mice. Moreover, colonic tissues of CHL1^−/− mice showed a marked increase in neutrophil and macrophage infiltration, be accompanied by more severe damage to intestinal epithelial cells and higher fluorescein isothiocyanate (FITC) leakage. Our results revealed deficiency of CHL1 exacerbated DSS-induced colitis, and this pathogenesis was potentially mediated by disruption of intestinal barrier integrity, indicating that CHL1 may be an attractive therapeutic target for inflammatory bowel diseases (IBDs) in mice.

Downregulation of Adhesion Molecule CHL1 in B Cells but Not T Cells of Patients with Major Depression and in the Brain of Mice with Chronic Stress

Depression is a common serious mental disorder with unclear pathogenesis. Currently, specific diagnostic biomarkers are yet to be characterized. The close homolog of L1 (CHL1) is a L1 family cell adhesion molecule involved in the regulation of neuronal survival and growth. Although genome-wide expression profiling of human lymphoblastoid cell lines (LCLs) reported neural cell adhesion molecule (NCAM) L1 as a tentative biomarker for selective serotonin reuptake inhibitor (SSRI) antidepressant response, the involvement of CHL1 in depression is unclear. In this study, using a well-established chronic unpredictable mild stress (CUMS) depression mouse model, we examined the mRNA and protein expression of CHL1 in normal control, CUMS, vehicle (VEH), fluoxetine (FLU), and clozapine (CLO) groups. We found that in the CUMS group, both mRNA and protein expression of CHL1 were downregulated in both the hippocampus and the cortex. Treatment of CUMS mice with FLU and CLO reversed CHL1 mRNA and protein expression. In the human study, we showed that CHL1 expression was significantly downregulated in monocytes of unipolar and bipolar depressive patients compared with healthy donors (HD) at both mRNA and protein levels. Consistently, ELISA showed that CHL1 levels in the serum of patients with depression were reduced and negatively correlated with their HRSD-21 scores. Further flow cytometry studies showed that the reduced number of CHL1 positive CD19⁺ and CD20⁺ B cells of patients with depression was subsequently reversed with antidepressant treatment. Our findings suggested that downregulation of CHL1 from both immune cells and the brain may be linked to the immunopathogenesis of depression. In conclusion, CHL1 may be an important predictive marker for both diagnosis and treatment outcome of depression.

CHL1 promotes insulin secretion and negatively regulates the proliferation of pancreatic β cells

Cell adhesion molecule L1-like protein (CHL1) is a member of neural recognition molecules of immunoglobulin superfamily primarily expressing in the nervous system. CHL1 regulates neuronal migration, axonal growth, and dendritic projection. Downregulation of CHL1 has been reported in β cells of patients with type 2 diabetes (T2DM). However, the detailed role of CHL1 in β cells has not been characterized. In this study, Real-Time PCR and Western blot were applied to investigate the tissue/cell distribution and expression of CHL1. Gain- or loss-of function studies were conducted in MIN6 cells to determine the effects of CHL1 on cell proliferation, apoptosis, cell cycle, and insulin secretion. Following silencing of CHL1 in MIN6 cells (si-CHL1), insulin secretion and the number of insulin secretary granules <50 nm from the cell membrane decreased in response to 20 mM glucose. Besides, silencing of CHL1 induced cell proliferation, reduced apoptosis, and prolonged S phase and shortened G1 phase of the cell cycle, contrary to overexpressing of CHL1. The inhibitor of ERK1/2MAPK eliminated the effect of CHL1 deficiency on the proliferation of MIN6 cells. In addition, high-fat diet could result in increased islet volume and β cell proliferation, decreased CHL1 expression and activation of ERK pathway in mice islets. Consequently, CHL1 expression was decreased in islets of high-fat induced mice, which resulted in cell proliferation via ERK pathway and regulation of the cell cycle through p53 pathway. These mechanisms may contribute to pancreatic β cell compensatory hyperplasia in obesity-induced pre-diabetes.

Neuronal migration genes and a familial translocation t (3;17): candidate genes implicated in the phenotype

BACKGROUND

While Miller-Dieker syndrome critical region deletions are well known delineated anomalies, submicroscopic duplications in this region have recently emerged as a new distinctive syndrome. So far, only few cases have been described overlapping 17p13.3 duplications.

METHODS

In this study, we report on clinical and cytogenetic characterization of two new cases involving 17p13.3 and 3p26 chromosomal regions in two sisters with familial history of lissencephaly. Fluorescent In Situ Hybridization and array Comparative Genomic Hybridization were performed.

RESULTS

A deletion including the critical region of the Miller-Dieker syndrome of at least 2,9 Mb and a duplication of at least 3,6 Mb on the short arm of chromosome 3 were highlighted in one case. The opposite rearrangements, 17p13.3 duplication and 3p deletion, were observed in the second case. This double chromosomal aberration is the result of an adjacent 1:1 meiotic segregation of a maternal reciprocal translocation t(3,17)(p26.2;p13.3).

CONCLUSIONS

17p13.3 and 3p26 deletions have a clear range of phenotypic features while duplications still have an uncertain clinical significance. However, we could suggest that regardless of the type of the rearrangement, the gene dosage and interactions of CNTN4, CNTN6 and CHL1 in the 3p26 and PAFAH1B1, YWHAE in 17p13.3 could result in different clinical spectrums.

CHL1 and NrCAM are Primarily Expressed in Low Grade Pediatric Neuroblastoma

Background

Neural cell adhesion molecules like close homolog of L1 protein (CHL1) and neuronal glia related cell adhesion molecule (NrCAM) play an important role in development and regeneration of the central nervous system. However, they are also associated with cancerogenesis and progression in adult malignancies, thus gain increasing importance in cancer research. We therefore studied the expression of CHL1 and NrCAM according to the course of disease in children with neuroblastoma.

Methods

CHL1 and NrCAM expression levels were histologically assessed by tissue microarrays from surgically resected neuroblastoma specimens of 56 children. Expression of both markers was correlated to demographics as well as clinical data including metastatic dissemination and survival.

Results

CHL1 was expressed in 9% and NrCAM in 51% of neuroblastoma tissue samples. Expression of CHL1 was higher in patients with low Hughes grade 1a/b (p=0.01). NrCAM was more often detected in patients with a low International Staging System (INSS) score 1/2 (p=0.04).

Conclusion

CHL1 and NrCAM expression was associated with low-grade pediatric neuroblastoma. These adhesion molecules may play a role in early tumor development of neuroblastoma.

Long noncoding RNA CHL1-AS1 promotes cell proliferation and migration by sponging miR-6076 to regulate CHL1 expression in endometrial cancer

Endometrial cancer (EC) is deemed to be the most typical gynecologic malignant tumor. Despite the incidence of EC being lower in Asia than that in western countries, substantial increased incidence has been observed in the past few decades in Asia. Although various molecular testing methods and genomic science have developed, the overall prognosis is still disappointing. LncRNAs have been found to influence the progression of various cancers. CHL1-AS1 has been found to be upregulated in ovarian endometriosis, nevertheless, the molecular mechanism and biological function of CHL1-AS1 in EC have not been explored. In our exploration, both CHL1-AS1 and CHL1 were upregulated in EC cells. Knockdown of CHL1-AS1 or CHL1 inhibited cell proliferation and migration in EC. Furthermore, microRNA-6076 (miR-6076) could bind with CHL1-AS1 or CHL1, and regulate the expression of CHL1. Finally, absence of miR-6076 or overexpression of CHL1 can partially rescue the effect of CHL1-AS1 knockdown or miR-6076 upregulation on cell proliferation and migration, respectively. All in all, our research was the first endeavor to study the underlying mechanism of CHL1-AS1 in EC and confirmed that CHL1-AS1 regulated EC progression via targeting the miR-6076/CHL1 axis, offering new insight into treating EC.

[Effect of CHL1 gene on cell viability, invasiveness and apoptosis in neuroblastoma cells]

Objective: To investigate the effect and mechanisms of CHL1 gene overexpression on cell viability, invasiveness and apoptosis in neuroblastoma cells. Methods: The empty plasmid (pcDNA3.1 group) and CHL1 recombinant plasmid (pcDNA3.1-CHL1 group) were transfected into SK-N-SH human neuroblastoma cells, and the untransfected cells were used as blank control. Forty-eight hours after transfection, the protein expressions of CHL1, PCNA, MMP-2, Bax, STAT3 and p-STAT3 were detected by western blot. Meanwhile, cell viability, invasion and apoptosis were detected by MTT, transwell and flow cytometry assays, respectively. Results: The expression level of CHL1 protein in pcDNA3.1-CHL1 group was 0.612±0.052, which was higher than that of pcDNA3.1 group 0.122±0.014 and blank control group 0.120±0.013, with statistically significant difference (P<0.05). After 24, 48 and 72 hours of transfection, the absorbance (A) values of SK-N-SH cells in the pcDNA3.1-CHL1 group were 0.328±0.035, 0.502±0.051 and 0.688±0.064, respectively, whereas those in the pcDNA3.1 group were 0.562±0.050, 0.796±0.065 and 0.973±0.077, respectively. The differences were statistically significant (P<0.05). The invaded cells in the pcDNA3.1-CHL1 group were 104.9±3.7, which were lower than that in the pcDNA3.1 group (175.6±4.6), with statistically significant difference (P<0.05). Additionally, the apoptotic rate of pcDNA3.1-CHL1 cells was (23.46±1.22)%, which was higher than that in pcDNA3.1 group (3.45±0.20)%(P<0.05). Furthermore, the levels of PCNA, MMP-2, Bax and p-STAT3 proteins in pcDNA3.1-CHL1 group were 0.156±0.018, 0.122±0.015, 0.285±0.032 and 0.023±0.004, respectively, whereas those in pcDNA3.1 group were 0.542±0.053, 0.196±0.021, 0.073±0.009 and 0.057±0.007, respectively. There were statistically significant differences between two groups (P<0.05). Conclusion: Overexpression of CHL1 inhibits the cell viability and invasion, as well as induces apoptosis of neuroblastoma cells, which is related to the inhibition of STAT3 signaling pathway.

Protein expression of close homologue of L1 (CHL1) is a marker for overall survival in non-small cell lung cancer (NSCLC)

BACKGROUND

The cell adhesion molecule close homologue of L1 (CHL1) is a potential tumour suppressor and was recently detected in non-small cell lung cancer (NSCLC) specimens. The expression pattern, prognostic, and functional role of CHL1 in NSCLCs is unknown.

METHODS

We evaluated the protein expression of CHL1 by immunohistochemistry in 2161 NSCLC patients based on a tissue microarray. The results were correlated with clinical, histopathological, and patient survival data (Chi square test, t test, and log-rank test, respectively). A multivariate analysis (Cox regression) was performed to validate its impact on patients' survival.

RESULTS

CHL1 was expressed in NSCLC patients and was significantly overexpressed in lung adenocarcinomas and squamous cell carcinomas compared to neuroendocrine and large cell carcinomas of the lung (p < 0.001). CHL1 expression was associated with the T stage in adenocarcinomas (p = 0.011) and with metastatic lymph node status and UICC stage in squamous cell carcinomas (p = 0.034 and p = 0.035, respectively). Increased CHL1 expression was associated with improved survival in univariate (p = 0.031) and multivariate analyses (odds ratio 0.797, 95% confidence interval 0.677-0.939, p = 0.007).

CONCLUSION

The prognostic significance of CHL1 makes it a potential prognostic and therapeutic target and underlines its role as a tumour suppressor. Further validation studies and functional analyses are needed to investigate its potential role in tumourigenesis and dissemination.

Aberrant expression of CHL1 gene and long non-coding RNA CHL1-AS1, CHL1-AS2 in ovarian endometriosis

OBJECTIVE(S)

CHL1 (close homologue of L1 or cell adhesion molecule L1 like), also referred as CALL, is a member of the L1 gene family of neural cell adhesion molecules and belongs to immunoglobulin superfamily. This study aims to investigate the potential correlation of the CHL1 gene and the long non-coding RNAs (lncRNAs), i.e., CHL1-AS1 and CHL1-AS2, and to validate the expression patterns of CHL1 and CHL1-AS2 in ovarian endometriosis (EM).

STUDY DESIGN

Our previous microarray analyses (GSE86534) of 4 patients with ovarian EM indicated that CHL1 was the most upregulated mRNA in ectopic endometrium (EC) compared with eutopic endometrium (EU) tissues, and that its two antisense lncRNAs CHL1-AS1 and CHL1-AS2, exhibited the same expression pattern. We used a bioinformatics-based strategy to calculate the correlation among CHL1, CHL1-AS1 and CHL1-AS2. Gene set enrichment analysis (GSEA) was performed to analyze commonly enriched gene sets for CHL1-AS1 and CHL1-AS2. Using quantitative real-time polymerase chain reaction (qPCR), we examined the expression levels of CHL1 mRNA and lncRNA CHL1-AS2 in paired tissues of EC and EU from 30 EM patients and normal endometrium (NE) tissues from 27 controls using quantitative real-time polymerase chain reaction (qPCR). We also examined the expression of CHL1 protein in EC, EU and NE tissues using western blotting and immunohistochemistry (IHC).

RESULTS

CHL1, CHL1-AS1 and CHL1-AS2 were significantly correlated with each other given that the Pearson correlation values were > 0.9 using bioinformatic calculation. GSEA revealed that CHL1-AS1 and CHL1-AS2 were negatively associated with the same gene set "WAMUNYOKOLI_OVARIAN_CANCER_LMP". qPCR confirmed that the CHL1 and CHL1-AS2 expression levels were significantly higher in EC tissues than in EU and NE tissues, while they were not significantly different in EU compared with NE tissues. The relative expression levels of CHL1 and CHL1-AS2 in EC compared with EU tissues were positively significantly correlated (Pearson correlation coefficient = 0.421 and P value = 0.02). Elevated expression of CHL1 protein in EC tissues was detected by western blotting. IHC revealed that CHL1 protein expression levels enhanced in ectopic endometrial glands and stroma.

CONCLUSION(S)

Our results indicate a significant correlation among CHL1, CHL1-AS1 and CHL1-AS2, which might be involved in the development of ovarian EM and serve as novel targets for future research.

Neuroplasticity, Neurotransmission and Brain-Related Genes in Major Depression and Bipolar Disorder: Focus on Treatment Outcomes in an Asiatic Sample

Introduction

Mood disorders are common and disabling disorders. Despite the availability of over 100 psychotropic compounds, only one-third of patients benefit from first-line treatments. Over the past 20 years, many studies have focused on the biological factors modulating disease risk and response to treatments, but with still inconclusive data. In order to improve our current knowledge, in this study, we investigated the role of a set of genes involved in different pathways (neurotransmission, neuroplasticity, circadian rhythms, transcription factors, signal transduction and cellular metabolism) in the treatment outcome of major depressive disorder (MDD) and bipolar disorder (BD) after naturalistic pharmacological treatment.

Methods

Totals of 242 MDD, 132 BD patients and 326 healthy controls of Asian ethnicity (Koreans) were genotyped for polymorphisms within 19 genes. Response and remission after 6–8 weeks of treatment with antidepressants and mood stabilizers were evaluated. In secondary analyses, genetic associations with disease risk and some disease-associated features (age of onset, suicide attempt and psychotic BD) were also tested.

Results

None of the variants within the investigated genes was significantly associated with treatment outcomes. Some marginal association (uncorrected p < 0.01) was observed for HTR2A, BDNF, CHL1, RORA and HOMER1 SNPs. In secondary analyses, HTR2A (rs643627, p = 0.002) and CHL1 (rs4003413, p = 0.002) were found associated with risk for BD, HOMER1 (rs6872497, p = 0.002) with lifetime history of suicide attempt in patients, and RORA with early onset and presence of psychotic features in BD. Marginal results were also observed for ST8SIA2 and COMT.

Discussion

Despite limitations linked to multiple testing on small samples, methodological shortcomings and small significance of the findings, this study may support the involvement of some candidate genes in the outcomes of treatments for mood disorders, as well as in BD risk and other disease features.

Electronic supplementary material

The online version of this article (10.1007/s12325-018-0781-2) contains supplementary material, which is available to authorized users.

Silencing of the FTO gene inhibits insulin secretion: An in vitro study using GRINCH cells

Expression of fat mass and obesity-associated gene (FTO) and ADP-ribosylation factor-like 15 (ARL15) in human islets is inversely correlated with HbA_1c. However, their impact on insulin secretion is still ambiguous. Here in, we investigated the role of FTO and ARL15 using GRINCH (Glucose-Responsive Insulin-secreting C-peptide-modified Human proinsulin) clonal rat β-cells. GRINCH cells have inserted GFP into the human C-peptide insulin gene. Hence, secreted CpepGFP served to monitor insulin secretion. mRNA silencing of FTO in GRINCH cells showed a significant reduction in glucose but not depolarization-stimulated insulin secretion, whereas ARL15 silencing had no effect. A significant down-regulation of insulin mRNA was observed in FTO knockdown cells. Type-2 Diabetic islets revealed a reduced expression of FTO mRNA. In conclusion, our data suggest that fluorescent CpepGFP released from GRINCH cells may serve as a convenient marker for insulin secretion. Silencing of FTO expression, but not ARL15, inhibits insulin secretion by affecting metabolic signaling.

Overexpression of miR-21-5p promotes proliferation and invasion of colon adenocarcinoma cells through targeting CHL1

Background

This study aims to investigate the effect of miR-21-5p on process of colon adenocarcinoma (COAD) cells and its connection with neural cell adhesion molecule L1 (CHL1).

Methods

Different expressions of mRNAs and miRNAs were calculated with microarray analysis. QRT-PCR and western blot were performed to quantify miR-21-5p and CHL1 expression. Flow Cytometry, MTT assay, colony formation assay, transwell assay and ELISA were performed to evaluate propagation and invasiveness of COAD cells. Dual luciferase reporter assay was employed to scrutinize the relationship between miR-21-5P and CHL1. We performed in vivo experiment to detect the impact of miR-21-5p and CHL1 on COAD tumor growth.

Results

Expression level of miR-21-5p increased in both COAD tissues and cells. MTT and Cell cycle assay showed that overexpression of miR-21-5p accelerated proliferation of COAD cells. Transwell assay indicated that miR-21-5p promoted cell invasion. The result of dual luciferase reporter assay indicated that miR-21-5p targeted CHL1 directly and inhibited its expression. The result of in vivo experiments showed that down-regulation of miR-21-5p decreased the volume and weight of tumor, while knockdown of CHLI stimulated tumor growth.

Conclusions

The overexpression of miR-21-5p can promote propagation and invasiveness of COAD cells through inhibiting the expression of CHL1.

[Effects of CHL1 deficiency,a cell adhesion molecule,on the inflammatory bowel disease]

OBJECTIVE

To investigate the effects of deficiency of CHL1 in inflammatory bowel disease (IBD).

METHODS

Dextran Sulfate Sodium (DSS)-induced colitis model was used to study the effects of deficiency of CHL1 on the development of IBD. Ten CHL1(+/+) mice in C57/BL6 background were randomly divided into CHL1(+/+) group and DSS-induced CHL1(+/+) group. Ten CHL1(-/-) mice in C57/BL6 background were randomly divided into CHL1(-/-) group and DSS-induced CHL1(-/-) group. DSS-induced CHL1(+/+) group and DSS-induced CHL1(-/-)group were fed with 1.5% DSS for 7 days, and then drinking distilled water for 2 days. CHL1(+/+) group and CHL1(-/-) group as control group were fed with distilled water for 9 days. The changes of weight, survival, fecal blood and the change of colon length in this study were observed.

RESULTS

On the 7^th day, the weight of DSS-induced CHL1(-/-) group were reduced significantly, and DSS-induced CHL1(-/-) group had extreme mortality on the 9th day. The fecal blood of DSS-induced CHL1(-/-) group also had higher score than that of DSS-induced CHL1(+/+) group. In the DSS-induced CHL1(-/-) group,the length of colon was shortened obviously.

CONCLUSIONS

The loss of CHL1 aggravates the development of IBD.

CHL1 gene polymorphisms increase lung cancer susceptibility

Lung cancer represents a complex and malignant cancer. Close Homologue of L1 (CHL1) gene plays a crucial role in the progress of cancer. The aim of this study is to explore the association between CHL1 rs425366 polymorphism and lung cancer susceptibility in northeast of China. A hospital-based case-control study was carried out to collect relative characteristics. Logistic regression analysis was conducted to analyze the relationship between single nucleotide polymorphisms and lung cancer susceptibility. The results suggested that there was statistically significant difference between GT genotype and TT genotype of rs425366 and lung cancer susceptibility. In stratified analysis, TT genotype of rs425366 may increase the risk of lung adenocarcinoma. We also found that non-smoking individuals carrying T allele were more likely to develop lung cancer. Overall, our study may indicate that CHL1 gene may increase lung cancer susceptibility in northeast of China.

MicroRNA-Mediated Regulation of ITGB3 and CHL1 Is Implicated in SSRI Action

Background: Selective serotonin reuptake inhibitor (SSRI) antidepressant drugs are the first-line of treatment for major depressive disorder (MDD) but are effective in <70% of patients. Our earlier genome-wide studies indicated that two genes encoding for cell adhesion proteins, close homolog of L1 (CHL1) and integrin beta-3 (ITGB3), and microRNAs, miR-151a-3p and miR-221/222, are implicated in the variable sensitivity and response of human lymphoblastoid cell lines (LCL) from unrelated individuals to SSRI drugs.

Methods: The microRNAs miR-221, miR-222, and miR-151-a-3p, along with their target gene binding sites, were explored in silico using miRBase, TargetScan, microRNAviewer, and the UCSC Genome Browser. Luciferase reporter assays were conducted for demonstrating the direct functional regulation of ITGB3 and CHL1 expression by miR-221/222 and miR-151a-3p, respectively. A human LCL exhibiting low sensitivity to paroxetine was utilized for studying the phenotypic effect of CHL1 regulation by miR-151a-3p on SSRI response.

Results: By showing direct regulation of CHL1 and ITGB3 by miR-151a-3p and miR-221/222, respectively, we link these microRNAs and genes with cellular SSRI sensitivity phenotypes. We report that miR-151a-3p increases cell sensitivity to paroxetine via down-regulating CHL1 expression.

Conclusions: miR-151a-3p, miR-221/222 and their (here confirmed) respective target-genes, CHL1 and ITGB3, are implicated in SSRI responsiveness, and possibly in the clinical response to antidepressant drugs.

CHL1 hypermethylation as a potential biomarker of poor prognosis in breast cancer

The CHL1 gene encodes a cell-adhesion molecule proposed as being a putative tumour-suppressor gene in breast cancer (BC). However, neither the underlying molecular mechanisms nor the clinical value of CHL1 downregulation in BC has been explored. The methylation status of three CpG sites in the CHL1 promoter was analysed by pyrosequencing in neoplastic biopsies from 142 patients with invasive BC and compared with that of non-neoplastic tissues. We found higher CHL1 methylation levels in breast tumours than in non-neoplastic tissues, either from mammoplasties or adjacent-to-tumour, which correlated with lower levels of protein expression in tumours measured by immunohistochemistry. A panel of five BC cell lines was treated with two epigenetic drugs, and restoration of CHL1 expression was observed, indicating in vitro dynamic epigenetic regulation. CHL1 was silenced by shRNA in immortalized but non-neoplastic mammary cells, and enhanced cell proliferation and migration, but not invasion, were found by real-time cell analysis. The prognostic value of CHL1 hypermethylation was assessed by the log-rank test and fitted in a Cox regression model. Importantly, CHL1 hypermethylation was very significantly associated with shorter progression-free survival in our BC patient series, independent of age and stage (p = 0.001). In conclusion, our results indicate that CHL1 is downregulated by hypermethylation and that this epigenetic alteration is an independent prognostic factor in BC.

The cell adhesion molecule CHL1 interacts with patched-1 to regulate apoptosis during postnatal cerebellar development

The immunoglobulin superfamily adhesion molecule close homolog of L1 (CHL1) plays important roles during nervous system development. Here, we identified the hedgehog receptor patched-1 (PTCH1) as a novel CHL1-binding protein and showed that CHL1 interacts with the first extracellular loop of PTCH1 via its extracellular domain. Colocalization and co-immunoprecipitation of CHL1 with PTCH1 suggest an association of CHL1 with this major component of the hedgehog signaling pathway. The trans-interaction of CHL1 with PTCH1 promotes neuronal survival in cultures of dissociated cerebellar granule cells and of organotypic cerebellar slices. An inhibitor of the PTCH1-regulated hedgehog signal transducer, smoothened (SMO), and inhibitors of RhoA and Rho-associated kinase (ROCK) 1 and 2 prevent CHL1-dependent survival of cultured cerebellar granule cells and survival of cerebellar granule and Purkinje cells in organotypic cultures. In histological sections from 10- and 14-day-old CHL1-deficient mice, enhanced apoptosis of granule, but not Purkinje, cells was observed. The results of the present study indicate that CHL1 triggers PTCH1-, SMO-, RhoA- and ROCK-dependent signal transduction pathways to promote neuronal survival after cessation of the major morphogenetic events during mouse cerebellar development.

Hormones and nitrate: a two-way connection

During their sessile mode of life, plants need to endure variations in their environment such as a drastic variability in the nutrient concentration in soil solution. It is almost trivial to say that such fluctuations in the soil modify plant growth, development and phase transitions. However, the signaling pathways underlying the connections between nitrogen related signaling and hormonal signaling controlling growth are still poorly documented. This review is meant to present how nitrate/nitrogen controls hormonal pathways. Furthermore, it is very interesting to highlight the increasing evidence that the hormonal signaling pathways themselves seem to feed back control of the nitrate/nitrogen transport and assimilation to adapt nutrition to growth. This thus defines a feed-forward cycle that finely coordinates plant growth and nutrition.

Interaction between CHL1 and serotonin receptor 2c regulates signal transduction and behavior in mice

The serotonergic system plays important roles in multiple functions of the nervous system and its malfunctioning leads to neurological and psychiatric disorders. Here, we show that the cell adhesion molecule close homolog of L1 (CHL1), which has been linked to mental disorders, binds to a peptide stretch in the third intracellular loop of the serotonin 2c (5-HT2c) receptor through its intracellular domain. Moreover, we provide evidence that CHL1 deficiency in mice leads to 5-HT2c-receptor-related reduction in locomotor activity and reactivity to novelty, and that CHL1 regulates signaling pathways triggered by constitutively active isoforms of the 5-HT2c receptor. Furthermore, we found that the 5-HT2c receptor and CHL1 colocalize in striatal and hippocampal GABAergic neurons, and that 5-HT2c receptor phosphorylation and its association with phosphatase and tensin homolog (PTEN) and β-arrestin 2 is regulated by CHL1. Our results demonstrate that CHL1 regulates signal transduction pathways through constitutively active 5-HT2c receptor isoforms, thereby altering 5-HT2c receptor functions and implicating CHL1 as a new modulator of the serotonergic system.

Interaction of the cell adhesion molecule CHL1 with vitronectin, integrins, and the plasminogen activator inhibitor-2 promotes CHL1-induced neurite outgrowth and neuronal migration

The cell adhesion molecule close homolog of L1 (CHL1) plays important functional roles in the developing and adult nervous system. In search of the binding partners that mediate the diverse and sometimes opposing functions of CHL1, the extracellular matrix-associated proteins vitronectin and plasminogen activator inhibitor-2 (PAI-2) were identified as novel CHL1 interaction partners and tested for involvement in CHL1-dependent functions during mouse cerebellar development. CHL1-induced cerebellar neurite outgrowth and cell migration at postnatal days 6-8 were inhibited by a CHL1-derived peptide comprising the integrin binding RGD motif, and by antibodies against vitronectin or several integrins, indicating a vitronectin-dependent integrin-mediated pathway. A PAI-2-derived peptide, or antibodies against PAI-2, urokinase type plasminogen activator (uPA), uPA receptor, and several integrins reduced cell migration. CHL1 colocalized with vitronectin, PAI-2, and several integrins in cerebellar granule cells, suggesting an association among these proteins. Interestingly, at the slightly earlier age of 4-5 d, cerebellar neurons did not depend on CHL1 for neuritogenesis and cell migration. However, differentiation of progenitor cells into neurons at this stage was dependent on homophilic CHL1-CHL1 interactions. These observations indicate that homophilic CHL1 trans-interactions regulate differentiation of neuronal progenitor cells at early postnatal stages, while heterophilic trans-interactions of CHL1 with vitronectin, integrins, and the plasminogen activator system regulate neuritogenesis and neuronal cell migration at a later postnatal stage of cerebellar morphogenesis. Thus, within very narrow time windows in postnatal cerebellar development, distinct types of molecular interactions mediated by CHL1 underlie the diverse functions of this protein.

MicroRNA-590 promotes cervical cancer cell growth and invasion by targeting CHL1

MicroRNAs (miRNAs) may function as oncogenes or tumor suppressors. Here, we identified that miR-590-5p was up-regulated in human cervical cancer. Over-expression of miR-590-5p promoted cervical cancer cell growth, cell cycle and invasion via Growth curve, Colony formation, FACS and Transwell assays in HeLa and C33A cell lines. Subsequently, CHL1 was identified as a potential miR-590-5p target by bioinformatics analysis. Moreover, we showed that CHL1 was negatively regulated by miR-590-5p at the posttranscriptional level, via a specific target site within the 3'UTR by luciferase reporter assay. Furthermore, the mRNA and protein levels of CHL1 in cervical cancer cells were downregulated by miR-590-5p. And we identified the cell phenotype altered by miR-590-5p can be rescued by over-expression of CHL1. Therefore, our findings suggest that miR-590-5p acts as an oncogene by targeting the CHL1 gene and promotes cervical cancer proliferation. The findings of this study contribute to current understanding of the functions of miR-590-5p in cervical cancer.

miR-182 targets CHL1 and controls tumor growth and invasion in papillary thyroid carcinoma

In this study, we investigated the role and underlying mechanism of action of miR-182 in papillary thyroid carcinoma (PTC). Bioinformatics analysis revealed close homolog of LI (CHL1) as a potential target of miR-182. Upregulation of miR-182 was significantly correlated with CHL1 downregulation in human PTC tissues and cell lines. miR-182 suppressed the expression of CHL1 mRNA through direct targeting of the 3'-untranslated region (3'-UTR). Downregulation of miR-182 suppressed growth and invasion of PTC cells. Silencing of CHL1 counteracted the effects of miR-182 suppression, while its overexpression mimicked these effects. Our data collectively indicate that miR-182 in PTC promotes cell proliferation and invasion through direct suppression of CHL1, supporting the potential utility of miR-182 inhibition as a novel therapeutic strategy against PTC.

CHL1 is involved in human breast tumorigenesis and progression

Neural cell adhesion molecules (CAM) play important roles in the development and regeneration of the nervous system. The L1 family of CAMs is comprised of L1, Close Homolog of L1 (CHL1, L1CAM2), NrCAM, and Neurofascin, which are structurally related trans-membrane proteins in vertebrates. Although the L1CAM has been demonstrated play important role in carcinogenesis and progression, the function of CHL1 in human breast cancer is limited. Here, we found that CHL1 is down-regulated in human breast cancer and related to lower grade. Furthermore, overexpression of CHL1 suppresses proliferation and invasion in MDA-MB-231 cells and knockdown of CHL1 expression results in increased proliferation and invasion in MCF7 cells in vitro. Finally, CHL1 deficiency promotes tumor formation in vivo. Our results may provide a strategy for blocking breast carcinogenesis and progression.

Spectrins: a structural platform for stabilization and activation of membrane channels, receptors and transporters

This review focuses on structure and functions of spectrin as a major component of the membrane skeleton. Recent advances on spectrin function as an interface for signal transduction mediation and a number of data concerning interaction of spectrin with membrane channels, adhesion molecules, receptors and transporters draw a picture of multifaceted protein. Here, we attempted to show the current depiction of multitask role of spectrin in cell physiology. This article is part of a Special Issue entitled: Reciprocal influences between cell cytoskeleton and membrane channels, receptors and transporters. Guest Editor: Jean Claude Hervé.

Impaired interval timing and spatial-temporal integration in mice deficient in CHL1, a gene associated with schizophrenia

Interval timing is crucial for decision-making and motor control and is impaired in many neuropsychiatric disorders, including schizophrenia - a neurodevelopmental disorder with a strong genetic component. Several gene mutations, polymorphisms or rare copy number variants have been associated with schizophrenia. L1 cell adhesion molecules (L1CAMs) are involved in neurodevelopmental processes, and in synaptic function and plasticity in the adult brain. Mice deficient in the Close Homolog to L1 (CHL1) adhesion molecule show alterations of hippocampal and thalamo-cortical neuroanatomy as well as deficits in sensorimotor gating and exploratory behavior. We analyzed interval timing and attentional control of temporal and spatial information in male CHL1 deficient (KO) mice and wild type (WT) controls. In a 20-s peak-interval timing procedure (standard and reversed), KO mice showed a maintained leftward shift of the response function relative to WT, indicative of a deficit in memory encoding/decoding. In trials with 2, 5, or 10-s gaps, KO mice shifted their peak times less than WT controls at longer gap durations, suggesting a decreased (attentional) effect of interruptions. In the spatial-temporal task, KO mice made more working and reference memory errors than controls, suggestive of impaired use of spatial and/or temporal information. When the duration spent on the central platform of the maze was manipulated, WT mice showed fewer spatial errors at the trained duration than at shorter or longer durations, indicative of discrimination based upon spatial-temporal integration. In contrast, performance was similar at all tested durations in KO mice, indicative of control by spatial cues, but not by temporal cues. These results suggest that CHL1 KO mice selectively attend to the more relevant cues of the task, and fail to integrate more complex spatial-temporal information, possibly as a result of reduced memory capacity related to hippocampal impairment, and altered temporal-integration mechanisms possibly due to thalamo-cortical anomalies.