Lactate receptor GPR81 drives breast cancer growth and invasiveness through regulation of ECM properties and Notch ligand DLL4.

BACKGROUND: The lactate receptor GPR81 contributes to cancer development through unclear mechanisms. Here, we investigate the roles of GPR81 in three-dimensional (3D) and in vivo growth of breast cancer cells and study the molecular mechanisms involved. METHODS: GPR81 was stably knocked down (KD) in MCF-7 human breast cancer cells which were subjected to RNA-seq analysis, 3D growth, in situ- and immunofluorescence analyses, and cell viability- and motility assays, combined with KD of key GPR81-regulated genes. Key findings were additionally studied in other breast cancer cell lines and in mammary epithelial cells. RESULTS: GPR81 was upregulated in multiple human cancer types and further upregulated by extracellular lactate and 3D growth in breast cancer spheroids. GPR81 KD increased spheroid necrosis, reduced invasion and in vivo tumor growth, and altered expression of genes related to GO/KEGG terms extracellular matrix, cell adhesion, and Notch signaling. Single cell in situ analysis of MCF-7 cells revealed that several GPR81-regulated genes were upregulated in the same cell clusters. Notch signaling, particularly the Notch ligand Delta-like-4 (DLL4), was strikingly downregulated upon GPR81 KD, and DLL4 KD elicited spheroid necrosis and inhibited invasion in a manner similar to GPR81 KD. CONCLUSIONS: GPR81 supports breast cancer aggressiveness, and in MCF-7 cells, this occurs at least in part via DLL4. Our findings reveal a new GPR81-driven mechanism in breast cancer and substantiate GPR81 as a promising treatment target.

STAT3-EphA7 axis contributes to the progression of esophageal squamous cell carcinoma.

BACKGROUND: Our previous study has revealed that EphA7 was upregulated in patient-derived esophageal squamous cell carcinoma (ESCC) xenografts with hyper-activated STAT3, but its mechanism was still unclear. MATERIALS AND METHODS: To assess the association between EphA7 and STAT3, western blotting, immunofluorescence, ChIP assay, and qRT-PCR were conducted. Truncated mutation and luciferase assay were performed to examine the promoter activity of EphA7. CCK-8 assay and colony formation were performed to assess the proliferation of ESCC. Cell-derived xenograft models were established to evaluate the effects of EphA7 on ESCC tumor growth. RNA-seq analyses were used to assess the effects of EphA7 on related signals. RESULTS: In this study, EphA7 was found upregulated in ESCC cell lines with high STAT3 activation, and immunofluorescence also showed that EphA7 was co-localized with phospho-STAT3 in ESCC cells. Interestingly, suppressing STAT3 activation by the STAT3 inhibitor Stattic markedly inhibited the protein expression of EphA7 in ESCC cells, in contrast, activation of STAT3 by IL-6 obviously upregulated the protein expression of EphA7. Moreover, the transcription of EphA7 was also mediated by the activation of STAT3 in ESCC cells, and the -2000∼-1500 region was identified as the key promoter of EphA7. Our results also indicated that EphA7 enhanced the cell proliferation of ESCC, and silence of EphA7 significantly suppressed ESCC tumor growth. Moreover, EphA7 silence markedly abolished STAT3 activation-derived cell proliferation of ESCC. Additionally, RNA-seq analyses indicated that several tumor-related signaling pathways were significantly changed after EphA7 downregulation in ESCC cells. CONCLUSION: Our results showed that the transcriptional expression of EphA7 was increased by activated STAT3, and the STAT3 signaling may act through EphA7 to promote the development of ESCC.

Modulation of EphA7 and pEphA7 Protein Expression: Potential Biomarkers for Early Detection of Hepatocellular Carcinoma.

BACKGROUND: Hepatocellular carcinoma (HCC) is one of the leading drivers of cancer-related mortality in the world. As a result, researchers are constantly looking for ways to optimize the screening and diagnosis of the said malignancy. OBJECTIVE: To establish the mice model of hepatocellular carcinoma with the administration of a suitable dose of diethylnitrosamine (DEN) and examine the utility of EphA7 and pEphA7 as ideal diagnostic markers in HCC. METHODS: Swiss Albino (BALB/c) mice of around 10-12 weeks old were exposed to a known hepatocarcinogen-diethylnitrosamine at a dose of 20 mg/kg body weight at weekly intervals for a period of 4, 8, 12, & 16 weeks. Blood was collected from mice of different experimental groups, and age-matched control and serum were separated from whole blood samples. The liver homogenate was prepared after completion of treatment, and the resulting supernatant was used for enzyme assays. A range of liver biomarker enzyme assays such as Gamma-glutamyl transpeptidase (GGT), Acetylcholine esterase (AChE), GPx activity and GSH level, Heme oxygenase-1 (HO-1), GPC3 and alpha-fetoprotein (AFP) level along with the expression of Caspase-3, EphA7 and pEphA7 were evaluated. RESULTS: An elevation in body weight and relative liver weight across the treatment period (4, 8, 12, 16 weeks) was observed in DEN-treated mice. Significant differences in GGT levels between control and DEN treated mice were noted in the present study (P < 0.005). In the 16th week of the treatment period, a significant difference in AchE level was noted between the treated and control group (P < 0.001). However, there was no statistically significant difference in the levels of SGOT and SGPT levels between the control and DEN treated groups (P > 0.001). Lower GSH and GPx levels were demonstrated in the treated mice as compared to control over all the treatment period. Loss of Caspase-3 expression and significant differences in expression of HO-1 activity in treated vs. non-treated group of mice were observed. Significant differences in EphA7 and pEphA7 protein expression levels were noted in the DEN-treated vs. control groups across all the treatment periods (4 weeks: P < 0.05; 8 weeks: P < 0.05; 12 weeks:  P < 0.005; 16 weeks: P < 0.05). CONCLUSION: The present study indicated that EphA7 and phosphoEphA7 over-expression might contribute to the malignancy transition, invasion development, and metastasis of HCC. As a result, along with the known markers such as AFP and others, EphA7 and pEphA7 could be a very putative biomarkers of HCC, particularly at a very early stage of cancer development.

The identification and validation of EphA7 hypermethylation, a novel biomarker, in cervical cancer.

BACKGROUND: Aberrant methylation of EphA7 has been reported in the process of carcinogenesis but not in cervical cancer. Therefore, an integration study was performed to explore the association between EphA7 hypermethylation and cervical cancer and validate the potential value of EphA7 hypermethylation in the diagnosis of cervical cancer. METHODS: We performed an integration study to identify and validate the association between EphA7 methylation and cervical cancer. First, data on EphA7 methylation and expression in cervical cancer were extracted and analyzed via bioinformatics tools. Subsequently, CRISPR-based methylation perturbation tools (dCas9-Tet1/DNMT3a) were constructed to further demonstrate the association between DNA methylation and EphA7 expression. Ultimately, the clinical value of EphA7 methylation in cervical cancer was validated in cervical tissues and Thinprep cytologic test (TCT) samples by methylation-specific PCR (MSP) and quantitative methylation-specific PCR (QMSP), respectively. RESULTS: Pooled analysis showed that EphA7 promoter methylation levels were significantly increased in cervical cancer compared to normal tissues (P < 0.001) and negatively correlated with EphA7 expression. These prediction results were subsequently confirmed in cell lines; moreover, CRISPR-based methylation perturbation tools (dCas9-Tet1/DNMT3a) demonstrated that DNA methylation participates in the regulation of EphA7 expression directly. Consistent with these findings, the methylation level and the positive rate of EphA7 gradually increased with severity from normal to cancer stages in TCT samples (P < 0.01). CONCLUSIONS: EphA7 hypermethylation is present in cervical cancer and is a potential biomarker for the diagnosis of cervical cancer.

The role of EphA7 in different tumors.

Ephrin receptor A7 (EphA7) is a member of the Eph receptor family. It is widely involved in signal transduction between cells, regulates cell proliferation and differentiation, and participates in developing neural tubes and brain. In addition, EphA7 also has a dual role of tumor promoter and tumor suppressor. It can participate in cell proliferation, migration and apoptosis through various mechanisms, and affect tumor differentiation, staging and prognosis. EphA7 may be a potential diagnostic marker and tumor treatment target. This article reviews the effects of EphA7 on a variety of tumor biological processes and pathological characteristics, as well as specific effects and regulatory mechanisms.

Circulating microRNA-944 and its target gene EPHA7 as a potential biomarker for colorectal cancer.

MicroRNAs (miRNAs) have critical roles in colorectal cancer (CRC) tumorigenesis and development. It has been reported that Eph receptor A7 (EphA7) was a potential target of miR-944 which is transcriptionally activated in cancer. The aim of this study was to explore the expression profile of miR-944 and its target gene EPHA7 in the serum of Egyptian CRC patients. 150 CRC patients, 50 adenomatous polyps (AP) patients, and 100 healthy controls were included. Serum miR-944 was downregulated (0.304 ± 0.0512) while serum EPHA7 was upregulated (3.163 ± 0.610) in CRC and AP patients versus controls and discriminated aganst these groups by Receiver operating characteristic curve (ROC) analysis. miR-944 presented the highest diagnostic accuracy for CRC patients from control (AUC = 0.90). Moreover obvious prognostic power in distinguishing AP from CRC (AUC = 0.87). In conclusion, miR-944 and EPHA7 are potential genetic markers of CRC predisposition and novel potential non-invasive diagnostic biomarkers for CRC.

Satb2 Regulates EphA7 to Control Soma Spacing and Self-Avoidance of Cortical Pyramidal Neurons.

Soma spacing and dendritic arborization during brain development are key events for the establishment of proper neural circuitry and function. Transcription factor Satb2 is a molecular node in regulating the development of the cerebral cortex, as shown by the facts that Satb2 is required for the regionalization of retrosplenial cortex, the determination of callosal neuron fate, and the regulation of soma spacing and dendritic self-avoidance of cortical pyramidal neurons. In this study, we explored downstream effectors that mediate the Satb2-implicated soma spacing and dendritic self-avoidance. First, RNA-seq analysis of the cortex revealed differentially expressed genes between control and Satb2 CKO mice. Among them, EphA7 transcription was dramatically increased in layers II/III of Satb2 CKO cortex. Overexpression of EphA7 in the late-born cortical neurons of wild-type mice via in utero electroporation resulted in soma clumping and impaired self-avoidance of affected pyramidal neurons, which resembles the phenotypes caused by knockdown of Satb2 expression. Importantly, the phenotypes by Satb2 knockdown was rescued by reducing EphA7 expression in the cortex. Finally, ChIP and luciferase reporter assays indicated a direct suppression of EphA7 expression by Satb2. These findings provide new insights into the complexity of transcriptional regulation of the morphogenesis of cerebral cortex.

microRNA-196b promotes esophageal squamous cell carcinogenesis and chemoradioresistance by inhibiting EPHA7, thereby restoring EPHA2 activity.

Esophageal cancer (EC) is extremely aggressive and has a very poor survival rate. Esophageal squamous cell carcinoma (ESCC) accounts for 80% of all ECs worldwide, with the majority of the remaining 20% being esophageal adenocarcinoma (EAC). Due to its occult and insidious presentation, ESCC is typically diagnosed and treated in its advanced stages, thereby limiting the success of present therapeutic modalities. microRNAs (miRNAs) can function as tumor suppressors or oncogenes, playing critical roles in cancer initiation and progression by regulating target genes in oncogenic pathways. In the current study, we demonstrated that microRNA-196b (miR-196b) is one of the most upregulated miRNAs in both ESCC and EAC. miR-196b was overexpressed in ESCC and EAC cell lines, cellular exosomal RNAs, and ESCC tissue samples. Functional studies revealed that miR-196b acted as an oncomiR by directly targeting a tumor suppressor, ephrin type-A receptor 7 (EPHA7). EPHA7 abrogates the activity of ephrin type-A receptor 2 (EPHA2), a key molecule involved in the epithelial-to-mesenchymal transition (EMT) and MAPK/ERK pathways, mediating resistance to UV and chemoradiotherapy in both ESCC and EAC. Taken together, these findings suggest that miR-196b is a strong candidate molecular target for EC treatment.

EPHA7 haploinsufficiency is associated with a neurodevelopmental disorder.

Ephrin receptor and their ligands, the ephrins, are widely expressed in the developing brain. They are implicated in several developmental processes that are crucial for brain development. Deletions in genes encoding for members of the Eph/ephrin receptor family were reported in several neurodevelopmental disorders. The ephrin receptor A7 gene (EPHA7) encodes a member of ephrin receptor subfamily of the protein-tyrosine kinase family. EPHA7 plays a role in corticogenesis processes, determines brain size and shape, and is involved in development of the central nervous system. One patient only was reported so far with a de novo deletion encompassing EPHA7 in 6q16.1. We report 12 additional patients from nine unrelated pedigrees with similar deletions. The deletions were inherited in nine out of 12 patients, suggesting variable expressivity and incomplete penetrance. Four patients had tiny deletions involving only EPHA7, suggesting a critical role of EPHA7 in a neurodevelopmental disability phenotype. We provide further evidence for EPHA7 deletion as a risk factor for neurodevelopmental disorder and delineate its clinical phenotype.

EPHA7 mutation as a predictive biomarker for immune checkpoint inhibitors in multiple cancers.

BACKGROUND: A critical and challenging process in immunotherapy is to identify cancer patients who could benefit from immune checkpoint inhibitors (ICIs). Exploration of predictive biomarkers could help to maximize the clinical benefits. Eph receptors have been shown to play essential roles in tumor immunity. However, the association between EPH gene mutation and ICI response is lacking. METHODS: Clinical data and whole-exome sequencing (WES) data from published studies were collected and consolidated as a discovery cohort to analyze the association between EPH gene mutation and efficacy of ICI therapy. Another independent cohort from Memorial Sloan Kettering Cancer Center (MSKCC) was adopted to validate our findings. The Cancer Genome Atlas (TCGA) cohort was used to perform anti-tumor immunity and pathway enrichment analysis. RESULTS: Among fourteen EPH genes, EPHA7-mutant (EPHA7-MUT) was enriched in patients responding to ICI therapy (FDR adjusted P < 0.05). In the discovery cohort (n = 386), significant differences were detected between EPHA7-MUT and EPHA7-wildtype (EPHA7-WT) patients regarding objective response rate (ORR, 52.6% vs 29.1%, FDR adjusted P = 0.0357) and durable clinical benefit (DCB, 70.3% vs 42.7%, FDR adjusted P = 0.0200). In the validation cohort (n = 1144), significant overall survival advantage was observed in EPHA7-MUT patients (HR = 0.62 [95% confidence interval, 0.39 to 0.97], multivariable adjusted P = 0.0367), which was independent of tumor mutational burden (TMB) and copy number alteration (CNA). Notably, EPHA7-MUT patients without ICI therapy had significantly worse overall survival in TCGA cohort (HR = 1.33 [95% confidence interval, 1.06 to 1.67], multivariable adjusted P = 0.0139). Further gene set enrichment analysis revealed enhanced anti-tumor immunity in EPHA7-MUT tumor. CONCLUSIONS: EPHA7-MUT successfully predicted better clinical outcomes in ICI-treated patients across multiple cancer types, indicating that EPHA7-MUT could serve as a potential predictive biomarker for immune checkpoint inhibitors.

3D Genome of macaque fetal brain reveals evolutionary innovations during primate corticogenesis.

Elucidating the regulatory mechanisms of human brain evolution is essential to understanding human cognition and mental disorders. We generated multi-omics profiles and constructed a high-resolution map of 3D genome architecture of rhesus macaque during corticogenesis. By comparing the 3D genomes of human, macaque, and mouse brains, we identified many human-specific chromatin structure changes, including 499 topologically associating domains (TADs) and 1,266 chromatin loops. The human-specific loops are significantly enriched in enhancer-enhancer interactions, and the regulated genes show human-specific expression changes in the subplate, a transient zone of the developing brain critical for neural circuit formation and plasticity. Notably, many human-specific sequence changes are located in the human-specific TAD boundaries and loop anchors, which may generate new transcription factor binding sites and chromatin structures in human. Collectively, the presented data highlight the value of comparative 3D genome analyses in dissecting the regulatory mechanisms of brain development and evolution.

Identification of the soluble EphA7-interacting protein Nicalin as a regulator of EphA7 expression.

A soluble form of EphA7 (sEphA7) has been found to antagonize the role of full-length EphA7 (EphA7-FL) to stabilize the membrane level of the tight junction protein Claudin6 (CLDN6) during Xenopus pronephros development. However, the mechanism underlying this antagonistic effect remains unclear. In this study, we identified Nicalin, a Nicastrin-like protein, as a novel sEphA7-interacting protein using immunoprecipitation (IP)/mass spectrometry (MS). In HEK293 cells, Nicalin interacted with sEphA7 and they predominantly co-localized in the endoplasmic reticulum (ER). Interestingly, Nicalin diminished the protein level of sEphA7 in the membranous fraction but increased that in the insoluble cytoplasmic fraction with a reduced molecular weight, suggesting that Nicalin restricts the entry of sEphA7 into the ER for further modification. sEphA7 probably acted as a chaperone and enhanced the membrane level of EphA7-FL and the formation of EphA7 complex, however, this effect was reversed by Nicalin. Our work suggested that Nicalin limits sEphA7 secretion, thereby preventing the formation of EphA7 complex. These results demonstrated the potential role of Nicalin in regulating EphA7 expression and revealed a potential mechanism underlying the antagonistic effect between sEphA7 and EphA7-FL.

Down-regulation of HCP5 inhibits cell proliferation, migration, and invasion through regulating EPHA7 by competitively binding miR-101 in osteosarcoma

Patients with osteosarcoma (OS) usually have poor overall survival because of frequent metastasis. Long non-coding RNAs (lncRNAs) have been reported to be associated with tumorigenesis and metastasis. In this study, we investigated the expression and roles of lncRNA human histocompatibility leukocyte antigen (HLA) complex P5 (HCP5) in OS, aiming to provide a novel molecular mechanism for OS. HCP5 was up-regulated both in OS tissues and cell lines and high expression of HCP5 was associated to low survival in OS patients. Down-regulation of HCP5 inhibited cell proliferation, migration, and invasion, suggesting its carcinogenic role in OS. miR-101 was targeted by HCP5 and its expression was decreased in OS. The inhibitor of miR-101 reversed the impact of HCP5 down-regulation on cell proliferation, apoptosis, and metastasis in OS. Ephrin receptor 7 (EPHA7) was proved to be a target of miR-101 and had ability to recover the effects of miR-101 inhibitor in OS. In conclusion, lncRNA HCP5 knockdown suppressed cell proliferation, migration, and invasion, and induced apoptosis through depleting the expression of EPHA7 by binding to miR-101, providing a potential therapeutic strategy of HCP5 in OS.

Erythropoietin-producing hepatocellular receptor A7 restrains estrogen negative feedback of luteinizing hormone via ephrin A5 in the hypothalamus of female rats.

We have previously shown that systemic injection of erythropoietin-producing hepatocellular receptor A7 (EPHA7)-Fc raises serum luteinizing hormone (LH) levels before ovulation in female rats, indicating the induction of EPHA7 in ovulation. In this study, we aimed to identify the mechanism and hypothalamus-pituitary-ovary (HPO) axis level underlying the promotion of LH secretion by EPHA7. Using an ovariectomized (OVX) rat model, in conjunction with low-dose 17ß-estradiol (E2) treatment, we investigated the association between EPHA7-ephrin (EFN)A5 signaling and E2 negative feedback. Various rat models (OVX, E2-treated OVX, and abarelix treated) were injected with the recombinant EPHA7-Fc protein through the caudal vein to investigate the molecular mechanism underlying the promotion of LH secretion by EPHA7. Efna5 was observed strongly expressed in the arcuate nucleus of the female rat by using RNAscope in situ hybridization. Our results indicated that E2, combined with estrogen receptor (ER)α, but not ERß, inhibited Efna5 and gonadotropin-releasing hormone 1 (Gnrh1) expressions in the hypothalamus. In addition, the systemic administration of EPHA7-Fc restrained the inhibition of Efna5 and Gnrh1 by E2, resulting in increased Efna5 and Gnrh1 expressions in the hypothalamus as well as increased serum LH levels. Collectively, our findings demonstrated the involvement of EPHA7-EFNA5 signaling in the regulation of LH and the E2 negative feedback pathway in the hypothalamus, highlighting the functional role of EPHA7 in female reproduction.

EphA7 is required for otic epithelial homeostasis by modulating Claudin6 in Xenopus.

Receptor tyrosine kinase EphA7 is specifically expressed in otic region in Xenopus early development. However, its role in otocyst development remains unknown. Knockdown of EphA7 by a specific morpholino oligonucleotide (MO) reduced the size of the otocyst and triggered otic epithelial cell extrusion. Interestingly, EphA7 depletion attenuated the membrane level of the tight junction protein Claudin6 (CLDN6). Utilizing the Cldn6 MO, we further confirmed that CLDN6 attenuation also led to otic epithelial cell extrusion. Our work suggested that EphA7 modulates the otic epithelial homeostasis through stabilizing the CLDN6 membrane level.

Long noncoding RNA KCNQ1OT1 promotes proliferation, migration, and invasion in maxillary sinus squamous cell carcinoma by regulating miR-204/EphA7 axis.

Long noncoding RNAs have been demonstrated to contribute to the development and progression of various cancers. However, the underlying regulatory mechanisms of KCNQ1OT1 in tumorigenesis of maxillary sinus squamous cell carcinoma (MSSCC) remain unknown. Herein, we found that KCNQ1OT1 expression was markedly upregulated in MSSCC tissues and MSSCC cell line (IMC-3) by using quantitative reverse transcription-polymerase chain reaction. Loss-of-function experiments revealed that the deletion of KCNQ1OT1 inhibited cell proliferation, migration, and invasion. Moreover, we confirmed KCNQ1OT1 could directly interact with miR-204 by bioinformatic prediction and dual luciferase assay, and miR-204 inhibitor markedly reversed MSSCC tumor phenotypes induced by shKCNQ1OT1. Finally, we demonstrated that KCNQ1OT1/miR-204 facilitated MSSCC progression by regulating Eph receptor A7 (EphA7). Taken together, these results revealed a novel regulatory mechanism KCNQ1OT1/miR-204/EphA7 axis, which could provide a new understanding of MSSCC tumorigenesis and develop potential targets for MSSCC therapy.

The Diagnostic Significance of PDGF, EphA7, CCR5, and CCL5 Levels in Colorectal Cancer.

In this study, we compared the levels of C-C chemokine receptor type 5 (CCR5), C-C motif chemokine ligand 5 (CCL5), platelet-derived growth factor (PDGF), and EphrinA7 (EphA7) in patients with colorectal carcinoma and healthy controls in order to investigate the significance and usability of these potential biomarkers in early diagnosis of colorectal cancer. The study included 70 colorectal carcinoma patients and 40 healthy individuals. The CCR5, CCL5, PDGF, and EphA7 levels were measured using ELISA in blood samples. PDGF-BB, EphA7, CCR5, and CCL5 levels of the patients with colorectal carcinoma were significantly higher compared to the control group (p < 0.001 for each comparison). Our logistic regression analysis (the area under the curve was 0.958) supports the notion that PDGF-BB, EphA7, and CCL5 are potential biomarkers for the diagnosis of colon cancer. The sensitivity, specificity, and positive and negative predictive values were found to be 87.9%, 87.5%, 92.1%, and 81.4%, respectively. To our knowledge, this is the first study that investigates the relationship between colorectal carcinoma and the four biomarkers CCL5, CCR5, PDGF, and EphA7. The significantly elevated levels of all these parameters in the patient group compared to the healthy controls indicate that they can be used for the early diagnosis of colorectal carcinoma.

Erythropoietin-producing hepatocellular A7 triggering ovulation indicates a potential beneficial role for polycystic ovary syndrome.

BACKGROUND: The ovulatory dysfunction mechanisms underlying polycystic ovary syndrome (PCOS) are not completely understood. And the roles of EPHA7 and EPHA7-regulated pathway factors in the pathogenesis of anovulation remain to be elucidated. METHODS: We used human granulosa cells (hGCs) of PCOS and non-PCOS patients to measure EPHA7 and other target gene expressions. We performed in vitro experiments in KGN cells to verify the molecular mechanisms. Additionally, we conducted in vivo loss- and gain-of-function studies using EPHA7 shRNA lentivirus and recombinant EPHA7-Fc protein injection to identify the ovulation effects of EPHA7. FINDINGS: EPHA7 functions as a critically positive upstream factor for the expression of ERK1/2-mediated C/EBPß. This protein, in turn, induced the expression of KLF4 and then ADAMTS1. Moreover, decreased abundance of EPHA7 was positively correlated with that of its downstream factors in hGCs of PCOS patients. Additionally, a 1-week functional EPHA7 shRNA lentivirus in rat ovaries contributed to decreased numbers of retrieved oocytes, and a 3-week functional lentivirus led to menstrual disorders and morphological polycystic changes in rat ovaries. More importantly, we found that EPHA7 triggered ovulation in rats, and it improved polycystic ovarian changes induced by DHEA in PCOS rats. INTERPRETATION: Our findings demonstrate a new role of EPHA7 in PCOS, suggesting that EPHA7 is an effective target for the development of innovative medicines to induce ovulation. FUND: National Key Research and Development Program of China, National Natural Science Foundation, Shanghai Municipal Education Commission--Gaofeng Clinical Medicine, and Shanghai Commission of Science and Technology.

EphA7 regulates claudin6 and pronephros development in Xenopus.

Eph/ephrin molecules are widely expressed during embryonic development, and function in a variety of developmental processes. Here we studied the roles of the Eph receptor EphA7 and its soluble form in Xenopus pronephros development. EphA7 is specifically expressed in pronephric tubules at tadpole stages and knockdown of EphA7 by a translation blocking morpholino led to defects in tubule cell differentiation and morphogenesis. A soluble form of EphA7 (sEphA7) was also identified. Interestingly, the membrane level of claudin6 (CLDN6), a tetraspan transmembrane tight junction protein, was dramatically reduced in the translation blocking morpholino injected embryos, but not when a splicing morpholino was used, which blocks only the full length EphA7. In cultured cells, EphA7 binds and phosphorylates CLDN6, and reduces its distribution at the cell surface. Our work suggests a role of EphA7 in the regulation of cell adhesion during pronephros development, whereas sEphA7 works as an antagonist.

Downstream mediators of Ten-m3 signalling in the developing visual pathway.

BACKGROUND: The formation of visuotopically-aligned projections in the brain is required for the generation of functional binocular circuits. The mechanisms which underlie this process are unknown. Ten-m3 is expressed in a broad high-ventral to low-dorsal gradient across the retina and in topographically-corresponding gradients in primary visual centres. Deletion of Ten-m3 causes profound disruption of binocular visual alignment and function. Surprisingly, one of the most apparent neuroanatomical changes-dramatic mismapping of ipsilateral, but not contralateral, retinal axons along the representation of the nasotemporal retinal axis-does not correlate well with Ten-m3's expression pattern, raising questions regarding mechanism. The aim of this study was to further our understanding of the molecular interactions which enable the formation of functional binocular visual circuits. METHODS: Anterograde tracing, gene expression studies and protein pull-down experiments were performed. Statistical significance was tested using a Kolmogorov-Smirnov test, pairwise-fixed random reallocation tests and univariate ANOVAs. RESULTS: We show that the ipsilateral retinal axons in Ten-m3 knockout mice are mismapped as a consequence of early axonal guidance defects. The aberrant invasion of the ventral-most region of the dorsal lateral geniculate nucleus by ipsilateral retinal axons in Ten-m3 knockouts suggested changes in the expression of other axonal guidance molecules, particularly members of the EphA-ephrinA family. We identified a consistent down-regulation of EphA7, but none of the other EphA-ephrinA genes tested, as well as an up-regulation of ipsilateral-determinants Zic2 and EphB1 in visual structures. We also found that Zic2 binds specifically to the intracellular domain of Ten-m3 in vitro. CONCLUSION: Our findings suggest that Zic2, EphB1 and EphA7 molecules may work as effectors of Ten-m3 signalling, acting together to enable the wiring of functional binocular visual circuits.