Epithelial membrane protein-1, peripheral myelin protein 22, and lens membrane protein 20 define a novel gene family

Structure of the lens MP20 mediated adhesive junction

Human lens fiber membrane intrinsic protein MP20 is the second most abundant membrane protein of the human eye lens. Despite decades of effort its structure and function remained elusive. Here, we determined the MicroED structure of full-length human MP20 in lipidic-cubic phase to a resolution of 3.5 Å. MP20 forms tetramers each of which contain 4 transmembrane α-helices that are packed against one another forming a helical bundle. Both the N- and C- termini of MP20 are cytoplasmic. We found that each MP20 tetramer formed adhesive interactions with an opposing tetramer in a head-to-head fashion. These interactions were mediated by the extracellular loops of the protein. The dimensions of the MP20 adhesive junctions are consistent with the 11 nm thin lens junctions. Investigation of MP20 localization in human lenses indicated that in young fiber cells MP20 was stored intracellularly in vesicles and upon fiber cell maturation MP20 inserted into the plasma membrane and restricted the extracellular space. Together these results suggest that MP20 forms lens thin junctions in vivo confirming its role as a structural protein in the human eye lens, essential for its optical transparency.

Single-cell atlas of the small intestine throughout the human lifespan demonstrates unique features of fetal immune cells

Proper development of mucosal immunity is critical for human health. Over the past decade, it has become evident that in humans, this process begins in utero. However, there are limited data on the unique features and functions of fetal mucosal immune cells. To address this gap, we integrated several single-cell ribonucleic acid sequencing datasets of the human small intestine (SI) to create an SI transcriptional atlas throughout the human life span, ranging from the first trimester to adulthood, with a focus on immune cells. Fetal SI displayed a complex immune landscape comprising innate and adaptive immune cells that exhibited distinct transcriptional programs from postnatal samples, especially compared with pediatric and adult samples. We identified shifts in myeloid populations across gestation and progression of memory T-cell states throughout the human lifespan. In particular, there was a marked shift of memory T cells from those with stem-like properties in the fetal samples to fully differentiated cells with a high expression of activation and effector function genes in adult samples, with neonatal samples containing both features. Finally, we demonstrate that the SI developmental atlas can be used to elucidate improper trajectories linked to mucosal diseases by implicating developmental abnormalities underlying necrotizing enterocolitis, a severe intestinal complication of prematurity. Collectively, our data provide valuable resources and important insights into intestinal immunity that will facilitate regenerative medicine and disease understanding.

Single cell atlas of human gastric muscle immune cells and macrophage-driven changes in idiopathic gastroparesis

Gastrointestinal immune cells, particularly muscularis macrophages (MM) interact with the enteric nervous system and influence gastrointestinal motility. Here we determine the human gastric muscle immunome and its changes in patients with idiopathic gastroparesis (IG). Single cell sequencing was performed on 26,000 CD45+ cells obtained from the gastric tissue of 20 subjects. We demonstrate 11 immune cell clusters with T cells being most abundant followed by myeloid cells. The proportions of cells belonging to the 11 clusters were similar between IG and controls. However, 9/11 clusters showed 578-11,429 differentially expressed genes. In IG, MM had decreased expression of tissue-protective and microglial genes and increased the expression of monocyte trafficking and stromal activating genes. Furthermore, in IG, IL12 mediated JAK-STAT signaling involved in the activation of tissue-resident macrophages and Eph-ephrin signaling involved in monocyte chemotaxis were upregulated. Patients with IG had a greater abundance of monocyte-like cells. These data further link immune dysregulation to the pathophysiology of gastroparesis.

First Characterization of the Transcriptome of Lung Fibroblasts of SSc Patients and Healthy Donors of African Ancestry

Systemic sclerosis (SSc) is a connective tissue disorder that results in fibrosis of the skin and visceral organs. SSc-associated pulmonary fibrosis (SSc-PF) is the leading cause of death amongst SSc patients. Racial disparity is noted in SSc as African Americans (AA) have a higher frequency and severity of disease than European Americans (EA). Using RNAseq, we determined differentially expressed genes (DEGs; q < 0.1, log2FC > |0.6|) in primary pulmonary fibroblasts from SSc lungs (SScL) and normal lungs (NL) of AA and EA patients to characterize the unique transcriptomic signatures of AA-NL and AA-SScL fibroblasts using systems-level analysis. We identified 69 DEGs in "AA-NL vs. EA-NL" and 384 DEGs in "AA-SScL vs. EA-SScL" analyses, and a comparison of disease mechanisms revealed that only 7.5% of DEGs were commonly deregulated in AA and EA patients. Surprisingly, we also identified an SSc-like signature in AA-NL fibroblasts. Our data highlight differences in disease mechanisms between AA and EA SScL fibroblasts and suggest that AA-NL fibroblasts are in a "pre-fibrosis" state, poised to respond to potential fibrotic triggers. The DEGs and pathways identified in our study provide a wealth of novel targets to better understand disease mechanisms leading to racial disparity in SSc-PF and develop more effective and personalized therapies.

Epithelial Membrane Protein 1 Promotes Sensitivity to RSL3-Induced Ferroptosis and Intensifies Gefitinib Resistance in Head and Neck Cancer

Epithelial membrane protein (EMP1), a member of the peripheral myelin protein (PMP22) family, is involved in the development of various human malignancies. However, the expression level of EMP1 and its functional role in head and neck squamous cell carcinoma (HNSCC) remain unclear to date. Ferroptosis, a newly characterized form of regulated cell death, plays an essential role in tumorigenesis. In this study, we aimed to investigate the expression levels of EMP1 in HNSCC and normal tissues, as well as to identify the function of EMP1 in regulating ferroptosis during the progression of HNSCC. To further explore the biological function of EMP1 in vitro, transient transfection was used to overexpress EMP1 in the HNSCC cell lines Hep2 and Detroit562. Functionally, our results indicated that EMP1 overexpression could not affect the initiation of ferroptosis directly but reinforced RSL3-induced ferroptosis on HNSCC cells. Furthermore, mechanical study indicated that EMP1 mediated the ferroptosis via cell density-regulated Hippo-TAZ pathway and regulated the expression of Rac1 and NOX1. In addition, our study demonstrated that EMP1 overexpression could promote gefitinib resistance by targeting the MAPK pathway. In summary, our findings indicate that EMP1 may act as an oncogene and serve as a therapeutic target against malignant progression of HNSCC.

Single-cell transcriptomic analysis of human colonic macrophages reveals niche-specific subsets

Macrophages are a heterogeneous population of cells involved in tissue homeostasis, inflammation, and cancer. Although macrophages are densely distributed throughout the human intestine, our understanding of how gut macrophages maintain tissue homeostasis is limited. Here we show that colonic lamina propria macrophages (LpMs) and muscularis macrophages (MMs) consist of monocyte-like cells that differentiate into multiple transcriptionally distinct subsets. LpMs comprise subsets with proinflammatory properties and subsets with high antigen-presenting and phagocytic capacity. The latter are strategically positioned close to the surface epithelium. Most MMs differentiate along two trajectories: one that upregulates genes associated with immune activation and angiogenesis, and one that upregulates genes associated with neuronal homeostasis. Importantly, MMs are located adjacent to neurons and vessels. Cell–cell interaction and gene network analysis indicated that survival, migration, transcriptional reprogramming, and niche-specific localization of LpMs and MMs are controlled by an extensive interaction with tissue-resident cells and a few key transcription factors.

Serum epithelial membrane protein 1 serves as a feasible biomarker in extrahepatic cholangiocarcinoma

BACKGROUND

Extrahepatic cholangiocarcinoma is a malignancy that originates from bile duct epithelium with an unfavorable prognosis. Epithelial membrane protein 1 was first discovered in 1995, functioning as an oncogene or anti-tumor gene in various cancers. However, the clinical role of epithelial membrane protein 1 extrahepatic cholangiocarcinoma remained unclear.

METHODS

Differentially expressed genes were identified using Gene Ontology and the Kyoto Encyclopedia and Genomes pathway analysis. Out of 183 extrahepatic cholangiocarcinoma patients and 61 healthy controls, the expression level of epithelial membrane protein 1 was detected and compared using reverse transcription-quantitative polymerase chain reaction analysis and western blot assay. Meanwhile, the diagnosis and prognosis of EMP1 in ECCA were measured by receiver operating characteristic and Kaplan-Meier analysis. Finally, the relationship between epithelial membrane protein 1 expression and clinicopathological indexes were compared to further verify the clinical role of epithelial membrane protein 1 in extrahepatic cholangiocarcinoma.

RESULTS

After analyzing data from GSE76297, GSE89749, and GSE26566GO, we found 1554 down-regulated and 1065 up-regulated genes. Through Gene Ontology and Kyoto Encyclopedia and Genomes analysis, extracellular matrix organization, extracellular structure organization, cholesterol metabolism, interleukin-17 signaling pathway, and vitamin digestion and absorption were significantly enriched and involved in targeted differentially expresses genes. Epithelial membrane protein 1 messenger ribonucleic acid was notably decreased in serum samples from extrahepatic cholangiocarcinoma patients, compared with that in healthy controls. Receiver operating characteristic analysis revealed that the area under the curve of epithelial membrane protein 1 messenger ribonucleic acid for the diagnosis of extrahepatic cholangiocarcinoma was 0.9281 (95% CI = 0.8967-0.9595). Moreover, the correlation analysis presented that epithelial membrane protein 1 expression was negatively correlated with lymph node metastasis, tumour node metastasis stage, cancer antigen 19-9 level, and carcinoembryonic antigen level.

CONCLUSION

Aberrant expression of epithelial membrane protein 1 contributed to distinguishing extrahepatic cholangiocarcinoma patients and healthy controls, and a low expression level of epithelial membrane protein 1 indicated an unfavorable prognosis. Hence, epithelial membrane protein 1 was a feasible and credible biomarker for extrahepatic cholangiocarcinoma diagnosis and prognosis, with high accuracy, sensitivity, and specificity.

Epithelial Membrane Protein 2 Suppresses Non-Small Cell Lung Cancer Cell Growth by Inhibition of MAPK Pathway

Epithelial membrane proteins (EMP1-3) are involved in epithelial differentiation and carcinogenesis. Dysregulated expression of EMP2 was observed in various cancers, but its role in human lung cancer is not yet clarified. In this study, we analyzed the expression of EMP1-3 and investigated the biological function of EMP2 in non-small cell lung cancer (NSCLC). The results showed that lower expression of EMP1 was significantly correlated with tumor size in primary lung tumors (p = 0.004). Overexpression of EMP2 suppressed tumor cell growth, migration, and invasion, resulting in a G1 cell cycle arrest, with knockdown of EMP2 leading to enhanced cell migration, related to MAPK pathway alterations and disruption of cell cycle regulatory genes. Exosomes isolated from transfected cells were taken up by tumor cells, carrying EMP2-downregulated microRNAs (miRNAs) which participated in regulation of the tumor microenvironment. Our data suggest that decreased EMP1 expression is significantly related to increased tumor size in NSCLC. EMP2 suppresses NSCLC cell growth mainly by inhibiting the MAPK pathway. EMP2 might further affect the tumor microenvironment by regulating tumor microenvironment-associated miRNAs.

A novel mutation of LIM2 causes autosomal dominant membranous cataract in a Chinese family

AIM

To identify mutations in the genes of a four-generation Chinese family with congenital membranous cataracts and investigate the morphologic changes and possible functional damage underlying the role of the mutant gene.

METHODS

Whole exome analysis of thirteen members of a four-generation pedigree affected with congenital membranous cataracts was performed; co-segregation analysis of identified variants was validated by Sanger sequencing. All members underwent detailed physical and complete eye examinations. The physical changes caused by the mutation were analyzed in silico through homology modeling. The lens fiber block from a patient was observed under a scanning electron microscope (SEM). Cell membrane proteins and cytoplasmic proteins from the human lenses donated by one patient with cataract in this family and from the dislocated lens resulted from the penetrating ocular trauma of a patient unrelated with this family were extracted, and the expression and localization of MP20 and Cx46 were detected by Western blot (WB) assay in these proteins.

RESULTS

A novel LIM2 heterozygous mutation (c.388C>T, p.R130C) was identified with congenital membranous cataracts inherited by an autosomal dominant (AD) pattern. Nystagmus and amblyopia were observed in all patients of this family, and exotropia and long axial length were observed in most patients. A/B ultrasound scan and ultrasound biomicroscopy revealed obvious thin crystalline lenses from 1.7 to 2.7 mm in central thickness in all cataract eyes. The bioinformatic analysis showed that the mutation was deleterious to the physiological function of LIM2-encoded MP20. Furthermore, by SEM, ultrastructure of the cataract nucleus showed that lens fiber cells (LFCs) remained morphologic characteristics of immature fiber cells, including flap cell surface with straight edges and lacking normal ball-and-socket joint boundaries, which implied that the differentiation of LFCs might be inhibited. Accumulation of MP20 and Cx46 in the cytoplasm was observed in the cytoplasm of the LFCs in human cataract lens.

CONCLUSION

We identify a novel heterozygous LIM2 (c.388C>T, p.R130C) mutation inherited by an AD pattern. This LIM2 mutation causes the abnormal sub-localization of MP20 and Cx46 in LFCs resulting in membranous cataracts.

Five genes as a novel signature for predicting the prognosis of patients with laryngeal cancer

In this study, we purpose to investigate a novel five-gene signature for predicting the prognosis of patients with laryngeal cancer. The laryngeal cancer datasets were obtained from The Cancer Genome Atlas (TCGA). Both univariate and multivariate Cox regression analysis was applied to screening for prognostic differential expressed genes (DEGs), and a novel gene signature was obtained. The performance of this Cox regression model was tested by receiver operating characteristic (ROC) curves and area under the curve (AUC). Further survival analysis for each of the five genes was carried out through the Kaplan-Meier curve and Log-rank test. Totally, 622 DEGs were screened from the TCGA datasets in this study. We construct a five-gene signature through Cox survival analysis. Patients were divided into low- and high-risk groups depending on the median risk score, and a significant difference of the 5-year overall survival was found between these two groups (P < .05). ROC curves verified that this five-gene signature had good performance to predict the prognosis of laryngeal cancer (AUC = 0.862, P < .05). In conclusion, the five-gene signature consist of EMP1, HOXB9, DPY19L2P1, MMP1, and KLHDC7B might be applied as an independent prognosis predictor of laryngeal cancer.

A novel missense mutation in LIM2 causing isolated autosomal dominant congenital cataract

Background: Congenital cataract is the most common cause of blindness in the world. Congenital cataracts are clinically and genetically heterogeneous and are mostly inherited in an autosomal dominant fashion. We identified the genetic cause of isolated autosomal dominant cataract in a four-generation British family and a Czech family.Methods: Whole exome sequencing (WES) was performed on one affected member in the British family and two affected members in the Czech family.Results: A novel missense variant c.388C > T; p.(R130C) was identified in the Lens integral membrane protein (LIM2) and found to co-segregate with disease in both families.Conclusions: Here we report the first autosomal dominant congenital cataract variant p.(R130C) in LIM2, causing a non-syndromic pulverulent and nuclear phenotype in European families.

The Pivotal Roles of the Epithelial Membrane Protein Family in Cancer Invasiveness and Metastasis

The members of the family of epithelial membrane proteins (EMPs), EMP1, EMP2, and EMP3, possess four putative transmembrane domain structures and are composed of approximately 160 amino acid residues. EMPs are encoded by the growth arrest-specific 3 (GAS3)/peripheral myelin protein 22 kDa (PMP22) gene family. The GAS3/PMP22 family members play roles in cell migration, growth, and differentiation. Evidence indicates an association of these molecules with cancer progression and metastasis. Each EMP has pro- and anti-metastatic functions that are likely involved in the complex mechanisms of cancer progression. We have recently demonstrated that the upregulation of EMP1 expression facilitates cancer cell migration and invasion through the activation of a small GTPase, Rac1. The inoculation of prostate cancer cells overexpressing EMP1 into nude mice leads to metastasis to the lymph nodes and lungs, indicating that EMP1 contributes to metastasis. Pro-metastatic properties of EMP2 and EMP3 have also been proposed. Thus, targeting EMPs may provide new insights into their clinical utility. Here, we highlight the important aspects of EMPs in cancer biology, particularly invasiveness and metastasis, and describe recent therapeutic approaches.

p53, miR-34a and EMP1-Newly Identified Targets of TFF3 Signaling in Y79 Retinoblastoma Cells

Trefoil factor family peptide 3 (TFF3) is supposed to have tumor suppressive functions in retinoblastoma (RB), but the functional pathway is not completely understood. In the study presented, we investigated the downstream pathway of TFF3 signaling in Y79 RB cells. Results from pG13-luciferase reporter assays and western blot analyses indicate induced p53 activity with an upregulation of miR-34a after TFF3 overexpression. Expression levels of the predicted miR-34a target epithelial membrane protein 1 (EMP1) are reduced after TFF3 overexpression. As revealed by WST-1 assay, BrdU, and DAPI cell counts viability and proliferation of Y79 cells significantly decrease following EMP1 knockdown, while apoptosis levels significantly increase. Opposite effects on Y79 cells’ growth could be shown after EMP1 overexpression. Caspase assays showed that EMP1 induced apoptosis after overexpression is at least partially caspase-3/7 dependent. Colony formation and soft agarose assays, testing for anchorage independent growth, revealed that EMP1 overexpressing Y79 cells have a significantly higher ability to form colonies. In in ovo chicken chorioallantoic membrane (CAM) assays inoculated EMP1 overexpressing Y79 cells form significantly larger CAM tumors. Moreover, miR-34a overexpression increases sensitivity of Y79 cells towards RB chemotherapeutics, however, without involvement of EMP1. In summary, the TFF3 signaling pathway in Y79 RB cells involves the activation of p53 with downstream induction of miR-34a and subsequent inhibition of EMP1.

EMP1 regulates cell proliferation, migration, and stemness in gliomas through PI3K-AKT signaling and CD44

Glioblastoma multiforme (GBM) is an intracranial tumor; the feature is higher malignant and poorer prognosis. The search for therapeutic targets for gliomas has always been a focus of research in the field of neurology. The unusual expression of epithelial membrane protein 1 (EMP1) has been proved in most tumors. In our study, we determined the expression level of EMP1 expression in glioma tissues. There were higher levels of EMP1 in glioma tissues-particularly GBM tissues-than those in normal brain tissues. Then we discovered that silencing EMP1 inhibited glioma cell invasion and proliferation through inhibiting the PI3K-AKT signaling pathway. Subsequently, we investigated the function of EMP1 on glioma stem cells and found that it regulates the expression of CD44 in such cells to promote stemness. Taken together, the new strategies for the treatment of glioma may be provided by these finding, thereby improving the prognosis associated with it.

Epithelial membrane protein 1 promotes tumor metastasis by enhancing cell migration via copine-III and Rac1

Tumor metastasis is the most common cause of cancer death. Elucidation of the mechanism of tumor metastasis is therefore important in the development of novel, effective anti-cancer therapies to reduce cancer mortality. Interaction between cancer cells and surrounding stromal cells in the tumor microenvironment is a key factor in tumor metastasis. Using a co-culture assay system with human prostate cancer LNCaP cells and primary human prostate stromal cells, we identified epithelial membrane protein 1 (EMP1) as a gene with elevated expression in the cancer cells. The orthotopic injection of LNCaP cells overexpressing EMP1 (EMP1-LNCaP cells) into the prostate of nude mice induced lymph node and lung metastases, while that of control LNCaP cells did not. EMP1-LNCaP cells had higher cell motility and Rac1 activity than control LNCaP cells. These results were also observed in other lines of cancer cells. We newly identified copine-III as an intracellular binding partner of EMP1. Knockdown of copine-III attenuated the increased cell motility and Rac1 activity in EMP1-LNCaP cells. Reduced cell motility and Rac1 activity following knockdown of copine-III in EMP1-LNCaP cells were recovered by re-expression of wild-type copine-III, but not of a copine-III mutant incapable of interacting with EMP1, suggesting the importance of the EMP1–copine-III interaction. Phosphorylated and activated Src and a Rac guanine nucleotide exchange factor Vav2 were found to be involved in the EMP1-induced enhancement of cell motility and Rac1 activation. Moreover, EMP1 was highly expressed in prostate cancer samples obtained from patients with higher Gleason score. These results demonstrate that upregulation of EMP1 significantly increases cancer cell migration that leads to tumor metastasis, suggesting that EMP1 may play an essential role as a positive regulator of tumor metastasis.

Loss of epithelial markers is an early event in oral dysplasia and is observed within the safety margin of dysplastic and T1 OSCC biopsies

Oral squamous cell carcinoma (OSCC) is a highly aggressive cancer that is associated with poor 5-year patient survival. Disease treatment is further compounded by the difficulty in predicting pre-cancerous tissues that will progress to OSCC and the high recurrence rates following surgical resection. Here we have assessed expression of the oral epithelial markers E-cadherin, EMP1 and 5T4 and the pro-invasive N-cadherin proteins using fully characterised antibodies and quantitative immunofluorescence microscopy in normal tissue (NT), fibroepithelial polyp (FEP), low-grade dysplasia (LGD), high-grade dysplasia (HGD), T1 OSCC and T4 OSCC biopsies. Decreased E-cadherin expression was associated with FEP, LGD and HGD biopsies, demonstrating that loss of E-cadherin is an early event within abnormal epithelium and occurs in the absence of an E- to N-cadherin switch, the latter of which was only observed in T4 OSCC. Furthermore, loss of E-cadherin and EMP1 is an indicator of LGD (p = 0.0006) and loss of E-cadherin, EMP1 and 5T4 an indicator of HGD (p = 0.0006). Expression patterns of E-cadherin, EMP1 and N-cadherin could predict abnormal epithelium in LGD, HGD, T1 and T4 OSCC biopsies (z-value = 0 for all disease grades) and allowed classification of LGD (z = 1.47), HGD (z = 2.138), T1 (z = 1.05) and T4 OSCC (z = 1.49) biopsies. Therefore, these markers provide a useful means to predict abnormal epithelium in patient biopsies. Linear regression and coefficient of determination analysis revealed positive correlation with a NT>LGD>HGD disease transition but low correlation with a putative HGD>T1 OSCC>T4 OSCC disease transition. Furthermore, expression of E-cadherin, EMP1, 5T4 and N-cadherin in pathologically normal surgical safety margins of LGD, HGD and T1 OSCC patient biopsies revealed significant differences to NT and the use of safety margins or FEP as ‘normal tissue’ controls introduced Type II errors in all patient cohorts. This work forms the basis for further investigation of the role of E-cadherin loss in abnormal epithelium and in the development of automated analyses for use in cancer diagnostics.

Antenatal dexamethasone exposure differentially affects distinct cortical neural progenitor cells and triggers long-term changes in murine cerebral architecture and behavior

Antenatal administration of synthetic glucocorticoids (sGC) is the standard of care for women at risk for preterm labor before 34 gestational weeks. Despite their widespread use, the type of sGC used and their dose or the dosing regimens are not standardized in the United States of America or worldwide. Several studies have identified neural deficits and the increased risk for cognitive and psychiatric disease later in life for children administered sGC prenatally. However, the precise molecular and cellular targets of GC action in the developing brain remain largely undefined. In this study, we demonstrate that a single dose of glucocorticoid during mid-gestation in mice leads to enhanced proliferation in select cerebral cortical neural stem/progenitor cell populations. These alterations are mediated by dose-dependent changes in the expression of cell cycle inhibitors and in genes that promote cell cycle re-entry. This leads to changes in neuronal number and density in the cerebral cortex at birth, coupled to long-term alterations in neurite complexity in the prefrontal cortex and hippocampus in adolescents, and changes in anxiety and depressive-like behaviors in adults.

EMP1, EMP 2, and EMP3 as novel therapeutic targets in human cancer

The epithelial membrane protein genes 1, 2, and 3 (EMP1, EMP2, and EMP3) belong to the peripheral myelin protein 22-kDa (PMP22) gene family, which consists of at least seven members: PMP22, EMP1, EMP2, EMP3, PERP, brain cell membrane protein 1, and MP20. This review addresses the structural and functional features of EMPs, detailing their tissue distribution and functions in the human body, their expression pattern in a variety of tumors, and highlighting the underlying mechanisms involved in carcinogenesis. The implications in cancer biology, patient prognosis prediction, and potential application in disease therapy are discussed. For example, EMP1 was reported to be a biomarker of gefitinib resistance in lung cancer and contributes to prednisolone resistance in acute lymphoblastic leukemia patients. EMP2 functions as an oncogene in human endometrial and ovarian cancers; however, characteristics of EMP2 in urothelial cancer fulfill the criteria of a suppressor gene. Of particular interest, EMP3 overexpression in breast cancer is significantly related to strong HER-2 expression. Co-expression of HER-2 and EMP3 is the most important indicator of progression-free and metastasis-free survival for patients with urothelial carcinoma of the upper urinary tract. Altogether, discovery of pharmacological inhibitors and/or regulators of EMP protein activity could open novel strategies for enhanced therapy against EMP-mediated human diseases.

The expression and function of epithelial membrane protein 1 in laryngeal carcinoma

In this study, we compared the expression of epithelial membrane protein 1 (EMP1) on the steady-state mRNA level (by quantitative real-time PCR) and on the protein level (by western immunoblot and immunohistochemistry) in 51 pairs of laryngeal carcinoma tissues and matched cancer-free peritumor tissues, and we analyzed the correlation between EMP1 expression and different clinicopathological factors. Furthermore, we ectopically expressed EMP1 in human laryngeal carcinoma Hep-2 cells and examined the effects on cell viability, apoptosis, colonogenicity, and motility, by MTT assay, flow cytometry, colony formation assay and Transwell migration assay, respectively. EMP1 expression (on both the mRNA and protein levels) was significantly lower in the cancer tissues than in matched peritumor tissues (P<0.05). In laryngeal cancers, the level of EMP1 protein was correlated with histological grade (P<0.05), but not with age, gender, clinical stage, cancer subtype or lymph node metastasis (P>0.05). Functionally, ectopic expression of EMP1 in Hep-2 cells significantly reduced cell viability, colony formation, and migration, but enhanced apoptosis. Therefore, EMP1 is a tumor suppressor in laryngeal carcinoma. Boosting EMP1 expression in laryngeal carcinoma initiates multiple anticancer phenotypes and thus presents a promising therapeutic strategy for laryngeal cancer.

Suppression of trophoblast cell surface antigen 2 enhances proliferation and migration in liver fluke-associated cholangiocarcinoma

BACKGROUND AND AIM

Trophoblast cell surface antigen 2 (TROP2) or tumor-associated calcium signal transducer 2 (TACSTD2) is a 36-kDa type I transmembrane glycoprotein and exerts dual functions as an oncogene and tumor suppressor in cancer cells. In this study, we investigated the expression and functions of TROP2 in liver fluke-associated cholangiocarcinoma (CCA).

MATERIAL AND METHODS

TROP2 expression in 85 CCA tissues was detected by using immunohistochemistry. The methylation status of TROP2 promoter was studied in 15 matched pairs of normal and CCA formalin fixed paraffin embedded (FFPE) tissues using the bisulfite genomic sequencing (BGS) method. The functions of TROP2 on cancer cell behavior were investigated using siRNA in CCA cell lines. Proliferation, migration and invasion assays were performed. A PCR array was used to evaluate the impact of TROP2 knockdown on the gene expression profiles.

RESULTS

TROP2 was highly expressed in all normal bile duct epithelia, but significantly down-regulated in CCA cells. Sixty percent of CCA revealed promoter hypermethylation compared to the corresponding adjacent normal tissues. TROP2 knockdown significantly enhanced the proliferation and migration in CCA cell lines, and altered the expressions of MARCK, EMP1 and FILIP1L.

CONCLUSION

We provide new evidence that TROP2 is epigenetically down-regulated and operates as a negative regulator of cell proliferation and migration in liver fluke-associated CCA.

Proteomic Analysis of Lipid Raft-Like Detergent-Resistant Membranes of Lens Fiber Cells

PURPOSE

Plasma membranes of lens fiber cells have high levels of long-chain saturated fatty acids, cholesterol, and sphingolipids-key components of lipid rafts. Thus, lipid rafts are expected to constitute a significant portion of fiber cell membranes and play important roles in lens biology. The purpose of this study was to characterize the lens lipid raft proteome.

METHODS

Quantitative proteomics, both label-free and iTRAQ methods, were used to characterize lens fiber cell lipid raft proteins. Detergent-resistant, lipid raft membrane (DRM) fractions were isolated by sucrose gradient centrifugation. To confirm protein localization to lipid rafts, protein sensitivity to cholesterol removal by methyl-β-cyclodextrin was quantified by iTRAQ analysis.

RESULTS

A total of 506 proteins were identified in raft-like detergent-resistant membranes. Proteins identified support important functions of raft domains in fiber cells, including trafficking, signal transduction, and cytoskeletal organization. In cholesterol-sensitivity studies, 200 proteins were quantified and 71 proteins were strongly affected by cholesterol removal. Lipid raft markers flotillin-1 and flotillin-2 and a significant fraction of AQP0, MP20, and AQP5 were found in the DRM fraction and were highly sensitive to cholesterol removal. Connexins 46 and 50 were more abundant in nonraft fractions, but a small fraction of each was found in the DRM fraction and was strongly affected by cholesterol removal. Quantification of modified AQP0 confirmed that fatty acylation targeted this protein to membrane raft domains.

CONCLUSIONS

These data represent the first comprehensive profile of the lipid raft proteome of lens fiber cells and provide information on membrane protein organization in these cells.

Molecular and clinical features of inherited neuropathies due to PMP22 duplication

PMP22 is a transmembrane glycoprotein component of myelin, important for myelin functioning. Mutation of PMP22 gene which encodes for the production of PMP22 glycoprotein is associated with a variety of inherited neuropathies. This literature review sought to review the molecular mechanism and clinical features of inherited neuropathies caused by PMP22 duplication. PMP22 duplication causes CMT1A which accounts for more than half of all CMT cases and about 70% of CMT1 cases. It manifests with muscle weakness, depressed reflexes, impaired distal sensation, hand and foot deformities, slowing of NCV and onion bulbs. With no specific treatment available, it is managed conservatively. Future treatment may be based on the molecular genetics of the disease.

A quantitative multiplex nuclease protection assay reveals immunotoxicity gene expression profiles in the rabbit model for vaginal drug safety evaluation

Any vaginal product that alters the mucosal environment and impairs the immune barrier increases the risk of sexually transmitted infections, especially HIV infection, which thrives on mucosal damage and inflammation. The FDA-recommended rabbit vaginal irritation (RVI) model serves as a first line selection tool for vaginal products; however, for decades it has been limited to histopathology scoring, insufficient to select safe anti-HIV microbicides. In this study we incorporate to the RVI model a novel quantitative nuclease protection assay (qNPA) to quantify mRNA levels of 25 genes representing leukocyte differentiation markers, toll-like receptors (TLR), cytokines, chemokines, epithelial repair, microbicidal and vascular markers, by designing two multiplex arrays. Tissue sections were obtained from 36 rabbits (6 per treatment arm) after 14 daily applications of a placebo gel, saline, 4% nonoxynol-9 (N-9), and three combinations of the anti-HIV microbicides tenofovir (TFV) and UC781 in escalating concentrations (highest: 10% TFV+2.5%UC781). Results showed that increased expression levels of toll-like receptor (TLR)-4, interleukin (IL)-1β, CXCL8, epithelial membrane protein (EMP)-1 (P<0.05), and decreased levels of TLR2 (P<0.05), TLR3 and bactericidal permeability increasing protein (BPI) (P<0.001) were associated with cervicovaginal mucosal alteration (histopathology). Seven markers showed a significant linear trend predicting epithelial damage (up with CD4, IL-1β, CXCL8, CCL2, CCL21, EMP1 and down with BPI). Despite the low tissue damage RVI scores, the high-dose microbicide combination gel caused activation of HIV host cells (SLC and CD4) while N-9 caused proinflammatory gene upregulation (IL-8 and TLR4) suggesting a potential for increasing risk of HIV via different mechanisms depending on the chemical nature of the test product.

Association of EMP1 with gastric carcinoma invasion, survival and prognosis

The aim of this study was to determine the expression and function of epithelial membrane protein 1 (EMP1) in gastric carcinoma. Gastric samples were taken from cancer lesions and adjacent normal tissue in gastric cancer patients immediately after endoscopic biopsy. A portion of the sample was either fixed in 4% paraformaldehyde and embedded in paraffin for immunohistochemistry or stored in liquid nitrogen for western blotting. In order to determine protein expression of EMP1 in gastric cancer (n=65) and normal tissue (n=27), semi-quantitative immunohistochemistry and western blotting were utilized. For in vitro studies, the human gastric cancer cell line SGC-7901 was maintained in RPMI-1640 medium supplemented with 10% fetal bovine serum. Recombinant lentivirus mediated overexpression of EMP1 in SGC-7901 cells was quantified with quantitative polymerase chain reaction (qPCR) and western blotting. Control SGC-7901 cells were transfected with an empty vector. To further study the effect of EMP1 overexpression in SGC-7901 cells, cell proliferation, cell apoptosis and migration and invasion assays were conducted. The expression of EMP1 was significantly lower in gastric cancer tissue compared to normal tissue using both immunohistochemistry (41.5 vs. 70.4% of tissues, P<0.05) and western blotting (0.153 ± 0.012 vs. 0.626 ± 0.058, P<0.05). Decreased expression of EMP1 was significantly correlated with tumor invasion, lymph node metastasis, clinical stage and histological grade of patients with gastric cancer (P<0.05). According to Kaplan-Meier analysis, low EMP1 expression correlated significantly with poor overall 5-year survival (47.4 vs. 70.3% survival, P<0.05). SGC-7901 cells transfected with EMP1 had a lower survival fraction, higher cell apoptosis (13.2 ± 1.5% vs. 2.2 ± 0.5%, P<0.05), significant decrease in migration and invasion (157.0 ± 16.0 and 112.0 ± 12.0, respectively vs. 243.0 ± 21.0 and 203.0 ± 19.0, respectively, P<0.05), higher caspase-9 (0.501 ± 0.050 vs. 0.114 ± 0.010, P<0.05) and lower VEGFC protein expression 0.135 ± 0.011 vs. 0.619 ± 0.074, P<0.05) relative to cells not transfected with EMP1. Low EMP1 expression in gastric cancer is associated with increased disease severity, suggesting that EMP1 may be a negative regulator of gastric cancer.

Epithelial membrane protein 1 negatively regulates cell growth and metastasis in colorectal carcinoma

AIM: To determine the expression and function of epithelial membrane protein 1 (EMP1) in colorectal carcinoma.

METHODS: Colorectal samples were taken from cancer lesions and adjacent normal tissue in colorectal cancer patients immediately after endoscopic biopsy. A portion of the sample was either fixed in 4% paraformaldehyde and embedded in paraffin for immunohistochemistry or stored in liquid nitrogen for Western blot. In order to determine protein expression of EMP1 in colorectal cancer (n = 63) and normal tissue (n = 31), semi-quantitative immunohistochemistry and Western blot were utilized. For in vitro studies, the human colorectal cancer cell line SW-480 was maintained in RPMI-1640 medium supplemented with 10% fetal bovine serum. Recombinant lentivirus mediated overexpression of EMP1 in SW-480 cells was quantified by real-time reverse transcription-polymerase chain reaction and Western blot. Control SW-480 cells were transfected with an empty vector. To further study the effect of EMP1 overexpression in SW-480 cells, cell proliferation, apoptosis, migration and invasion assays were conducted.

RESULTS: Expression of EMP1 was significantly lower in colorectal cancer tissue than in normal tissue using both immunohistochemistry (39.7% vs 90.3% of tissues, P < 0.05) and Western blot (0.126 ± 0.022 vs 0.632 ± 0.053, P < 0.05). The level of EMP1 protein expression was not correlated with gender, age, or tumor location. Decreased expression of EMP1 was significantly correlated with T stage, lymph node metastasis, clinic stage, and histological grade in patients with colorectal cancer (P < 0.05). According to Kaplan-Meier analysis, low EMP1 expression correlated significantly with poor overall five-year survival (34.2% vs 64.0% survival, P < 0.05). SW-480 cells transfected with EMP1 had a lower survival fraction, higher cell apoptosis (12.1% ± 1.3% vs 3.1% ± 0.6%, P < 0.05), a significant decrease in migration and invasion (124.0 ± 17.0 and 87.0 ± 12.0, respectively vs 213.0 ± 29.0 and 178.0 ± 21.0, respectively, P < 0.05), higher caspase-9 (0.635 ± 0.063 vs 0.315 ± 0.032, P < 0.05), and lower VEGFC protein expression (0.229 ± 0.021 vs 0.519 ± 0.055, P < 0.05) relative to cells not transfected with EMP1.

CONCLUSION: Low EMP1 expression in colorectal cancer is associated with increased disease severity, suggesting that EMP1 may be a negative regulator of colorectal cancer.

Transcriptional changes in organoculture of full-thickness human skin following topical application of all-trans retinoic acid

Objective

Retinoids are used as therapeutic agents for numerous skin diseases, for example, psoriasis, acne and keratinization disorders. The same substances have also been recognized in the treatment for hyperpigmentation disorders such as melasma.

Other studies on photo-damaged skin have shown that retinoids reduce wrinkles, surface roughness, mottled pigmentation, and visual skin appearance as a whole. We tested the hypothesis that an organoculture of full-thickness human skin could be used as a preclinical model to investigate the retinoid transcriptional profile in human skin in vitro.

Methods

Full-thickness skin explants were exposed to topically applied all-trans retinoic acid (RA) for 24 h. The gene expression profile was analysed using oligonucleotide microarrays, and data were validated with real-time (RT) PCR.

Results

We showed that the expression of 93 genes was significantly altered more than twofold. Several of the altered genes, for example, KRT4, CYP26 and LCN2, have previously been shown to be affected by RA in keratinocyte monocultures, reconstructed epidermis and skin biopsies from patients treated topically or orally with RA. In addition, genes, such as SCEL, NRIP1, DGAT2, RDH12 EfnB2, MAPK14, SAMD9 and CEACAM6 not previously reported to be affected by RA in human skin, were identified for the first time in this study.

Conclusion

The results in the present study show that full-thickness human explants represent a valuable pre-clinical model for studying the effects of retinoids in skin.

Résumé

EMP1, a novel poor prognostic factor in pediatric leukemia regulates prednisolone resistance, cell proliferation, migration and adhesion

Still 20% of pediatric acute lymphoblastic leukemia (ALL) patients relapse on or after current treatment strategies. Treatment failure is associated with resistance to prednisolone. We aimed to find new druggable targets that modulate prednisolone resistance. We generated microarray gene expression profiles of 256 pediatric ALL patient samples and identified a 3.4-fold increase in epithelial membrane protein 1 (EMP1) expression in in vitro prednisolone-resistant compared with -sensitive patients (P=0.003). EMP1 silencing in six precursor-B ALL (BCP-ALL) and T-ALL cell lines induced apoptosis and cell-cycle arrest leading to 84.1±4.5% reduction in survival compared with non-silencing control transduced cells (non-silencing control short hairpin, shNSC) (P=0.014). Moreover, EMP1 silencing sensitized to prednisolone up to 18.8-fold (P<0.001). EMP1 silencing also abrogated migration and adhesion to mesenchymal stromal cells (MSCs) by 78.3±9.0 and 29.3±4.1% compared with shNSC (P<0.05). We discovered that EMP1 contributes to MSC-mediated prednisolone resistance. Pathway analysis indicated that EMP1 signals through the Src kinase family. EMP1-high BCP-ALL patients showed a poorer 5-year event-free survival compared with EMP1-low patients (77±2 vs. 89±2%, P=0.003). Multivariate analysis taking along white blood cell count, age, prednisolone resistance and subtype identified EMP1 as an independent predictor for poor outcome in BCP-ALL (P=0.004, hazard ratio: 2.36 (1.31-4.25). This study provides preclinical evidence that EMP1 is an interesting candidate for drug development to optimize treatment of BCP-ALL.

EMP1, a member of a new family of antiproliferative genes in breast carcinoma

This study aimed to analyze the expression, clinical significance of epithelial membrane protein 1 (EMP1) in breast carcinoma and the biological effect in its cell line by EMP1 overexpression. Immunohistochemistry and western blot were used to analyze EMP1 protein expression in 67 cases of breast cancer and 35 cases of normal tissues to study the relationship between EMP1 expression and clinical factors. Quantitative real-time RT-PCR and western blot were used to detect the mRNA level and protein of EMP1. MTT assay, migration and invasion assays were also conducted as to the influence of the upregulated expression of EMP1 that might be found on MCF-7 cell biological effect. The relative amount of EMP1 protein in breast cancer tissue was found to be significantly lower than in normal tissues (P < 0.05). The level of EMP1 protein expression was correlated with T stages, lymph node metastasis, clinic stage, and histological grade (P < 0.05). Meanwhile, loss of EMP1 expression correlated significantly with poor overall survival time by Kaplan-Meier analysis (P < 0.05). The result shown that MCF-7 cell transfected EMP1 had a lower survival fraction, higher cell apoptosis, significant decrease in migration and invasion, higher caspase-9, and lower VEGFC protein expression compared with MCF-7 cell untransfected EMP1 (P < 0.05). EMP1 expression decreased in breast cancer and correlated significantly with lymph node metastasis, clinic stage, histological grade, and poor overall survival, T stages, suggesting that EMP1 may play important roles as a negative regulator to breast cancer MCF-7 cell by regulating the expression of caspase 9 and VEGFC protein.

EMP1 regulates caspase-9 and VEGFC expression and suppresses prostate cancer cell proliferation and invasion

This study aimed to analyze the expression, clinical significance of f epithelial membrane protejn-1 (EMP-1) in prostate carcinoma, and the biological effect in its cell line by EMP1 overexpression. Immunohistochemistry and Western blot were used to analyze EMP1 protein expression in 76 cases of prostate cancer and 34 cases of normal tissues to study the relationship between EMP1 expression and clinical factors. EMP1 lentiviral vector and empty vector were respectively transfected into prostate cancer PC-3 cell line. Quantitative real-time reverse transcription polymerase chain reaction and Western blot were used to detect the mRNA level and protein of EMP1. 3-[4,5-Dimethylthiazol-2-yl]-2,5-diphenyltetrazolium bromide assay, migration, and invasion assays were also conducted as to the influence of the upregulated expression of EMP1 that might be found on PC-3 cell biological effect. Immunohistochemistry: The level of EMP1 protein expression was found to be significantly lower in prostate cancer tissue than normal tissues (P < 0.05). Western blot: The relative amount of EMP1 protein in prostate cancer tissue was found to be significantly lower than in normal tissues (P < 0.05). The level of EMP1 protein expression was not correlated with age and prostate-specific antigen (PSA) concentration (P > 0.05), but it was correlated with T stages, lymph node metastasis, clinic stage, and Gleason score (P < 0.05). The result of biological function shown that PC-3 cell transfected EMP1 had a lower survival fraction, higher cell apoptosis, significant decrease in migration and invasion, higher caspase-9, and lower VEGFC protein expression compared with PC-3 cell untransfected EMP1 (P < 0.05). EMP1 expression decreased in prostate cancer and correlated significantly T stages, lymph node metastasis, clinic stage, and Gleason score, suggesting that EMP1 may play important roles as a negative regulator to prostate cancer PC-3 cell by regulating the expression of regulation of caspase-9 and VEGFC protein.

Regulation of PMP22 mRNA by G3BP1 affects cell proliferation in breast cancer cells

Background

Regulation of mRNAs is one way to control protein levels and thereby important cellular processes such as growth, invasion and apoptosis. G3BPs constitute a family of mRNA-binding proteins, shown to be overexpressed in several cancer types, including breast, colon and pancreas cancer. G3BP has been reported to both stabilize and induce degradation of specific mRNAs.

Results

Here, we show that G3BP1, but not G3BP2, supports proliferation of several breast cancer cell lines. Global gene expression analyses of G3BP1- and G3BP2-depleted cells indicate that primarily G3BP1, and much less G3BP2, influences mRNA expression levels. Peripheral myelin protein 22 (PMP22) was one gene that was significantly influenced by G3BP1 depletion which led to a 2–3 fold increased expression. Depletion of PMP22 resulted in increased proliferation and the G3BP1-mediated effect on proliferation was not seen upon PMP22-depletion.

Conclusions

This indicates a novel role for G3BP1 in the regulation of cell proliferation in breast cancer cells, perhaps via a regulatory effect on PMP22 expression.

EMP1 inhibits nasopharyngeal cancer cell growth and metastasis through induction apoptosis and angiogenesis

This study aimed to analyze the expression, clinical significance of epithelial membrane protein-1 (EMP1) in nasopharyngeal carcinoma, and the biological effect in its cell line by EMP1 overexpression. Immunohistochemistry and Western blot were used to analyze the EMP1 protein expression in 75 cases of nasopharyngeal cancer and 31 cases of normal tissues to study the relationship between EMP1 expression and clinical factors. Recombinant lentiviral vector was constructed to overexpress EMP1 and then infect nasopharyngeal cancer CNE2 cell line. Quantitative real-time RT-PCR and Western blot were used to detect the mRNA level and protein of EMP1. MTT assay, cell apoptosis, migration, and invasion assays were also conducted to determine the influence of the upregulated expression of EMP1 that might be found on CNE2 cells' biological effect. Immunohistochemistry and Western blot: The level of EMP1 protein expression was found to be significantly lower in nasopharyngeal cancer tissue than in the normal tissues (P < 0.05). Decreased expression of EMP1 was significantly correlated with T stages, lymph node metastasis, clinic stage, and histological grade of patients with nasopharyngeal cancer (P < 0.05). Meanwhile, the loss of EMP1 expression correlated significantly with poor overall survival time by Kaplan-Meier analysis (P < 0.05). The result of biological function has shown that CNE2 cell-transfected EMP1 had a lower survival fraction, higher cell apoptosis, significant decrease in migration and invasion, higher caspase-9, and lower vascular endothelial growth factor C protein expression compared with CNE2 cell-untransfected EMP1 (P < 0.05). EMP1 expression decreased in nasopharyngeal cancer and correlated significantly T stages, lymph node metastasis, clinic stage, histological grade, and poor overall survival, suggesting that EMP1 may play important roles as a negative regulator to nasopharyngeal cancer cell.

The four-transmembrane protein IP39 of Euglena forms strands by a trimeric unit repeat

Euglenoid flagellates have striped surface structures comprising pellicles, which allow the cell shape to vary from rigid to flexible during the characteristic movement of the flagellates. In Euglena gracilis, the pellicular strip membranes are covered with paracrystalline arrays of a major integral membrane protein, IP39, a putative four-membrane-spanning protein with the conserved sequence motif of the PMP-22/EMP/MP20/Claudin superfamily. Here we report the three-dimensional structure of Euglena IP39 determined by electron crystallography. Two-dimensional crystals of IP39 appear to form a striated pattern of antiparallel double-rows in which trimeric IP39 units are longitudinally polymerised, resulting in continuously extending zigzag-shaped lines. Structural analysis revealed an asymmetric molecular arrangement in the trimer, and suggested that at least four different interactions between neighbouring protomers are involved. A combination of such multiple interactions would be important for linear strand formation of membrane proteins in a lipid bilayer.

Promoter hypermethylation of the EMP3 gene in a series of 229 human gliomas

The epithelial membrane protein 3 (EMP3) is a candidate tumor suppressor gene in the critical region 19q13.3 for several solid tumors, including tumors of the nervous systems. The aim of this study was to investigate the EMP3 promoter hypermethylation status in a series of 229 astrocytic and oligodendroglial tumors and in 16 GBM cell lines. The analysis was performed by methylation-specific PCR and capillary electrophoresis. Furthermore, the EMP3 expression at protein level was evaluated by immunohistochemistry and Western blotting analysis. Associations of EMP3 hypermethylation with total 1p/19q codeletion, MGMT promoter hypermethylation, IDH1/IDH2 and TP53 mutations, and EGFR amplification were studied, as well as its prognostic significance. The EMP3 promoter hypermethylation has been found in 39.5% of gliomas. It prevailed in low-grade tumors, especially in gliomas with an oligodendroglial component, and in sGBMs upon pGBMs. In oligodendroglial tumors, it was strongly associated with both IDH1/IDH2 mutations and total 1p/19q codeletion and inversely with EGFR gene amplification. No association was found with MGMT hypermethylation and TP53 mutations. In the whole series, the EMP3 hypermethylation status correlated with 19q13.3 loss and lack of EMP3 expression at protein level. A favorable prognostic significance on overall survival of the EMP3 promoter hypermethylation was found in patients with oligodendroglial tumors.

Down-regulation of EMP1 is associated with epithelial hyperplasia and metaplasia in nasal polyps

AIMS

The aim of this study was to assess protein and mRNA expression of epithelial membrane protein 1 (EMP1) in the nasal mucosa of patients with nasal polyps (NP), and to determine what changes occur in response to glucocorticosteroid (GC) treatment.

METHODS AND RESULTS

NP tissue was obtained from 55 patients, 18 of whom were treated with nasal GCs (i.e. these 18 patients had NP biopsies taken before and after treatment). Biopsies of inferior turbinate mucosa from 30 healthy subjects were used as controls. Quantitative PCR and immunohistochemistry were performed to determine the expression levels of EMP1. EMP1 mRNA expression was significantly lower (2.77-fold) in tissues from NP patients before GC treatment when compared to controls, but was increased in these patients after GC treatment. EMP1 staining in nasal epithelium co-localized with both basal (p63(+)) and differentiated (CK18(+)) epithelial cells. Their immunoreactivity was significantly greater in controls than NP patients. EMP1 mRNA levels were lower in the epithelium with severe hyperplasia (1.79-fold) or with metaplasia (1.85-fold) as compared to those with mild to moderate hyperplasia or non-metaplastic epithelium, respectively. Positive correlations between EMP1 and other epithelial cell-related gene (e.g. JUN, PTGS2, AREG etc.) mRNAs were observed.

CONCLUSIONS

EMP1 could be a biomarker for aberrant epithelial remodelling and metaplasia in chronic inflammatory upper airway mucosa (e.g. NP).

Sonographic and electrodiagnostic features of hereditary neuropathy with liability to pressure palsies

In hereditary neuropathy with liability to pressure palsies (HNPP), the increase in distal motor latencies (DMLs) is often out of proportion to the slowing of conduction velocities, but the pathophysiological mechanism is still unclear. We used a combined electrophysiological and ultrasonographic (US) approach to provide insight into this issue. Twelve HNPP subjects underwent extensive electrophysiological studies and US measurements of the cross-sectional area (CSA) of several peripheral nerves. US nerve enlargement was only observed in the carpal tunnel, Guyon's canal, the elbow and the fibular head. We did not observe US abnormalities at sites where nerve entrapment is uncommon. An increase in DMLs was observed regardless of US nerve enlargement. The increased nerve CSA only in common sites of entrapment likely reflected the well-documented nerve vulnerability to mechanical stress in HNPP. No morphometric changes were seen in the distal nerve segments where compression/entrapment is unlikely, despite the fact that the DMLs were increased. These data suggest that factors other than mechanical stress are responsible for the distal slowing of action potential propagation. We speculate that a mixture of mechanical insults and an axon-initiated process in the distal nerves underlies the distal slowing and/or conduction failure in HNPP.

EMP-1 promotes tumorigenesis of NSCLC through PI3K/AKT pathway

This study examined the role of EMP-1 in tumorigenesis of non-small cell lung carcinoma (NSCLC) and the possible mechanism. Specimens were collected from 28 patients with benign lung diseases and 28 with NSCLC, and immunohistochemically detected to evaluate the correlation of EMP-1 expression to the clinical features of NSCLC. Recombinant adenovirus was constructed to over-express EMP-1 and then infect PC9 cells. Cell proliferation was measured by Ki67 staining. Western blotting was performed to examine the effect of EMP-1 on the PI3K/AKT signaling. Moreover, tumor xenografts were established by subcutaneous injection of PC9 cell suspension (about 5×10(7)/mL in 100 μL of PBS) into the right hind limbs of athymic nude mice. The results showed EMP-1 was significantly up-regulated in NSCLC patients as compared with those with benign lung diseases. Over-expression of EMP-1 promoted proliferation of PC9 cells, which coincided with the activation of the PI3K/AKT pathway. EMP-1 promoted the growth of xenografts of PC9 cells in athymic nude mice. It was concluded that EMP-1 expression may contribute to the development and progress of NSCLC by activating PI3K/AKT pathway.

The PMP22 gene and its related diseases

Peripheral myelin protein-22 (PMP22) is primarily expressed in the compact myelin of the peripheral nervous system. Levels of PMP22 have to be tightly regulated since alterations of PMP22 levels by mutations of the PMP22 gene are responsible for >50 % of all patients with inherited peripheral neuropathies, including Charcot-Marie-Tooth type-1A (CMT1A) with trisomy of PMP22, hereditary neuropathy with liability to pressure palsies (HNPP) with heterozygous deletion of PMP22, and CMT1E with point mutations of PMP22. While overexpression and point-mutations of the PMP22 gene may produce gain-of-function phenotypes, deletion of PMP22 results in a loss-of-function phenotype that reveals the normal physiological functions of the PMP22 protein. In this article, we will review the basic genetics, biochemistry and molecular structure of PMP22, followed by discussion of the current understanding of pathogenic mechanisms involving in the inherited neuropathies with mutations in PMP22 gene.

Absence of mutations in four genes encoding for congenital cataract and expressed in the human brain in Tunisian families with cataract and mental retardation

BACKGROUND

To identify the genetic defect associated with autosomal recessive congenital cataract (ARCC), mental retardation (MR) and ARCC, MR and microcephaly present in most patients in four Tunisian consanguineous families.

METHODS

We screened four genes implicated in congenital cataract by direct sequencing in two groups of patients; those affected by ARCC associated to MR and those who presented also microcephaly. Among its three genes PAX6, PITX3 and HSF4 are expressed in human brain and one gene LIM2 encodes for the protein MP20 that interact with the protein galectin-3 expressed in human brain and plays a crucial role in its development. All genes were screened by direct sequencing in two groups of patients; those affected by ARCC associated to MR and those who presented also microcephaly.

RESULTS

We report no mutation in the four genes of congenital cataract and its flanking regions. Only variations that did not segregate with the studied phenotypes (ARCC associated to MR, ARCC associated with MR and microcephaly) are reported. We detected three intronic variations in PAX6 gene: IVS4 -274insG (intron 4), IVS12 -174G>A (intron12) in the four studied families and IVS4 -195G>A (intron 4) in two families. Two substitutions polymorphisms in PITX3 gene: c.439 C>T (exon 3) and c.930 C>A (exon4) in one family. One intronic variation in HSF4 gene: IVS7 +93C>T (intron 7) identified in one family. And three intronic substitutions in LIM2 gene identified in all four studied families: IVS2 -24A>G (intron 2), IVS4 +32C>T (intron 4) and c.*15A>C (3'-downstream sequence).

CONCLUSION

Although the role of the four studied genes: PAX6, PITX3, HSF4 and LIM2 in both ocular and central nervous system development, we report the absence of mutations in all studied genes in four families with phenotypes associating cataract, MR and microcephaly.

Epithelial membrane protein 1 inhibits human spinal chondrocyte differentiation

The molecular mechanisms underlying human spinal chondrocyte differentiation remain unclear. We recently demonstrated that epithelial membrane protein 1 (EMP1) is highly expressed in degenerative intervertebral discs. EMP1 is involved in the differentiation of multiple cell types, including progenitor/pre-B cells, neurons, and podocytes. Therefore, we hypothesize that EMP1 may participate in the differentiation of spinal chondrocytes. We cultured chondrocytes from human nucleus pulposus. Through lentivirus-mediated knockdown and overexpression of EMP1, we find that EMP1 promotes cell proliferation and survival, alters cell morphology and cell cycle, reduces cell condensation, and inhibits cell hypertrophy and the expression of chondrocyte maturation markers such as collagen X, aggrecan, sex-determining region Y (SRY)-box 9, and runt-related transcription factor 2. We also show that EMP1 is not expressed in the ossification center of vertebrae but is highly expressed in the nucleus pulposus and growth plate, where chondrocytes are immature and endochondral ossification has not occurred. These results suggest that EMP1 inhibits human spinal chondrocyte differentiation.

Peripheral myelin protein-22 (PMP22) modulates alpha 6 integrin expression in the human endometrium

BACKGROUND

PMP22, a member of the GAS3 family of tetraspan proteins, is associated with a variety of neurological diseases. Previous studies have shown that PMP22 is expressed in proliferative endometrium, but its function within this tissue is poorly understood. In this study, we first characterized the expression of PMP22 in the human menstrual cycle and began to characterize its function in the endometrium.

METHODS

Using a combination of immunohistochemistry and quantitative PCR, we characterized the expression of PMP22 in both proliferative and secretory endometrium. Differences in PMP22 expression between proliferative and secretory endometrium were determined using a Mann-Whitney U test. In order to investigate the influence of PMP22 on α6 integrin expression, cells were created that ectopically overexpressed PMP22 or expressed a siRNA to inhibit its expression. These cells were analyzed for changes in integrins and binding to extracellular matrices.

RESULTS

In this study, we show that PMP22 expression is higher in proliferative phase than secretory phase. Functionally, we have begun to characterize the functional significance of this expression. Previous studies have suggested a link between PMP22 and α6 integrin, and therefore we asked whether PMP22 could associate or potentially modulate the expression of α6 integrin. Expression of both PMP22 and α6 integrin were detectable in endometrial epithelial and stromal cells, and we show that both proteins can associate and colocalize with each other. To understand if PMP22 directly altered the expression of a6 integrin, we examined cell lines with modulated levels of the protein. Overexpression of PMP22 was sufficient to increase α6 integrin surface expression with a concominant increase in binding to the extracellular matrix laminin, while a reduction in PMP22 suppressed α6 integrin surface expression.

CONCLUSION

These findings suggest a physiologic role for PMP22 on the expression of α6 integrin. We predict that this may be important for the maintainence of endometrial integrity and to the disease biology associated with altered levels of α6 integrin expression in the endometrium.

Fig1 facilitates calcium influx and localizes to membranes destined to undergo fusion during mating in Candida albicans

Few mating-regulated genes have been characterized in Candida albicans. C. albicans FIG1 (CaFIG1) is a fungus-specific and mating-induced gene encoding a putative 4-transmembrane domain protein that shares sequence similarities with members of the claudin superfamily. In Saccharomyces cerevisiae, Fig1 is required for shmoo fusion and is upregulated in response to mating pheromones. Expression of CaFIG1 was also strongly activated in the presence of cells of the opposite mating type. CaFig1-green fluorescent protein (GFP) was visible only during the mating response, when it localized predominantly to the plasma membrane and perinuclear zone in mating projections and daughter cells. At the plasma membrane, CaFig1-GFP was visualized as discontinuous zones, but the distribution of perinuclear CaFig1-GFP was homogeneous. Exposure to pheromone induced a 5-fold increase in Ca(2+) uptake in mating-competent opaque cells. Uptake was reduced substantially in the fig1Δ null mutant. CaFig1 is therefore involved in Ca(2+) influx and localizes to membranes that are destined to undergo fusion during mating.

Mechanic effect of pulsed focused ultrasound in tumor and muscle tissue evaluated by MRI, histology, and microarray analysis

The purpose of this study was to investigate the effect of pulsed high-intensity focused ultrasound (HIFU) to tumor and muscle tissue. Pulsed HIFU was applied to tumor and muscle tissue in C3H/Km mice. Three hours after HIFU treatment pre- and post-contrast T1-wt, T2-wt images and a diffusion-wt STEAM-sequence were obtained. After MR imaging, the animals were euthenized and the treated tumor and muscle was taken out for histology and functional genomic analysis. In the tumor tissue a slight increase of the diffusion coefficient could be found. In the muscle tissue T2 images showed increased signal intensity and post-contrast T1 showed a decreased contrast uptake in the center and a severe contrast uptake in the surrounding muscle tissue. A significant increase of the diffusion coefficient was found. Gene expression analysis revealed profound changes in the expression levels of 29 genes being up-regulated and 3 genes being down-regulated in the muscle tissue and 31 genes being up-regulated and 15 genes being down-regulated in the SCCVII tumor tissue. Seven genes were up-regulated in both tissue types. The highest up-regulated gene in the tumor and muscle tissue encoded for Mouse histone H2A.1 gene (FC=13.2±20.6) and Apolipoprotein E (FC=12.8±27.4) respectively MHC class III (FC=83.7±67.4) and hsp70 (FC=75.3±85.0). Immunoblot confirmed the presence of HSP70 protein in the muscle tissue. Pulsed HIFU treatment on tumor and muscle tissue results in dramatic changes in gene expression, indicating that the effect of pulsed HIFU is in some regard dependent and also independent of the tissue type.

The epithelial membrane protein 1 is a novel tight junction protein of the blood-brain barrier

In the central nervous system, a constant microenvironment required for neuronal cell activity is maintained by the blood-brain barrier (BBB). The BBB is formed by the brain microvascular endothelial cells (BMEC), which are sealed by tight junctions (TJ). To identify genes that are differentially expressed in BMEC compared with peripheral endothelial cells, we constructed a subtractive cDNA library from porcine BMEC (pBMEC) and aortic endothelial cells (AOEC). Screening the library for differentially expressed genes yielded 26 BMEC-specific transcripts, such as solute carrier family 35 member F2 (SLC35F2), ADP-ribosylation factor-like 5B (ARL5B), TSC22 domain family member 1 (TSC22D1), integral membrane protein 2A (ITM2A), and epithelial membrane protein 1 (EMP1). In this study, we show that EMP1 transcript is enriched in pBMEC compared with brain tissue and that EMP1 protein colocalizes with the TJ protein occludin in mouse BMEC by coimmunoprecipitation and in rat brain vessels by immunohistochemistry. Epithelial membrane protein 1 expression was transiently induced in laser-capture microdissected rat brain vessels after a 20-min global cerebral ischemia, in parallel with the loss of occludin immunoreactivity. The study identifies EMP1 as a novel TJ-associated protein of the BBB and suggests its potential role in the regulation of the BBB function in cerebral ischemia.

Comparative genomics of human-like Schistosoma japonicum genes indicates a putative mechanism for host-parasite relationship

Schistosoma japonicum causes schistosomiasis in humans and livestock in the Asia-Pacific region. We assembled more than 43,700 S. japonicum expressed sequence tags and conducted comparative genomic analyses between S. japonicum and its human host. Some schistosome genes showed exceptionally high similarity in nucleotide sequence to their human homologues, of which five exhibited anomalous phylogeny and human codon usage bias. The most plausible explanation for their presence is horizontal gene transfer from host to parasite. Functional evidence suggests that S. japonicum might exploit host endocrine and immune signals for cell development and maturation via these host-like genes.

Lengsin expression and function during zebrafish lens formation

A zebrafish ortholog of human lengsin was identified by EST analysis of an adult lens cDNA library. During zebrafish development, lengsin transcription is first detected at 24 h post-fertilization (hpf). Immunolocalization, using polyclonal antiserum generated against a Lengsin bacterial fusion protein, detects lens-specific protein in whole-mount embryos at 30 hpf. Lengsin expression in zebrafish follows the temporal expression of the alphaA- alphaB1- and betaB1-crystallin proteins in the lens. At 72 hpf, Lengsin is localized to a subpopulation of differentiating secondary fiber cells, while no expression is detected in the lens epithelial cells or central lens fibers. In the adult lens, Lengsin is restricted to a narrow band of cortical fibers and co-localizes with actin at the lateral faces of these interdigitating cells. Stable transgenic lines, using a 3 kb lengsin genomic fragment to regulate EGFP expression, recapitulate the Lengsin temporal and spatial expression patterns. Lengsin function in zebrafish lens formation was examined by antisense morpholino-mediated translation and mRNA splice inhibition. At 72 hpf, the lengsin morphant lenses are reduced in size and exhibit separations within the cortex due to defects in secondary fiber morphogenesis. The location of the morphant lens defects correlates with the Lengsin protein localization at this age. These results demonstrate Lengsin is required for proper fiber cell differentiation by playing roles in either cell elongation or the establishment of cell interactions.

Characterization of a familial t(16;22) balanced translocation associated with congenital cataract leads to identification of a novel gene, TMEM114, expressed in the lens and disrupted by the translocation

Molecular characterization of chromosomal rearrangements is a powerful resource in identification of genes associated with monogenic disorders. We describe the molecular characterization of a balanced familial chromosomal translocation, t(16;22)(p13.3;q11.2), segregating with congenital lamellar cataract. This led to the discovery of a cluster of lens-derived expressed sequence tags (ESTs) close to the 16p13.3 breakpoint. This region harbors a locus associated with cataract and microphthalmia. Long-range PCR and 16p13.3 breakpoint sequencing identified genomic sequence in a human genome sequence gap, and allowed identification of a novel four-exon gene, designated TMEM114, which encodes a predicted protein of 223 amino acids. The breakpoint lies in the promoter region of TMEM114 and separates the gene from predicted eye-specific upstream transcription factor binding sites. There is sequence conservation among orthologs down to zebrafish. The protein is predicted to contain four transmembrane domains with homology to the lens intrinsic membrane protein, LIM2 (also known as MP20), in the PMP-22/EMP/MP20 family. TMEM114 mutation screening in 130 congenital cataract patients revealed missense mutations leading to the exchange of highly-conserved amino acids in the first extracellular domain of the protein (p.I35T, p.F106L) in two separate patients and their reportedly healthy sibling and mother, respectively. In the lens, Tmem114 shows expression in the lens epithelial cells extending into the transitional zone where early fiber differentiation occurs. Our findings implicate dysregulation of expression of this novel human gene, TMEM114, in mammalian cataract formation.

Polymorphic assemblies and crystalline arrays of lens tetraspanin MP20

Members of the tetraspanin superfamily function as transmembrane scaffold proteins that mediate the assembly of membrane proteins into specific signaling complexes. Tetraspanins also interact with each other and concentrate membrane proteins into tetraspanin-enriched microdomains (TEMs). Here we report that lens-specific tetraspanin MP20 can form multiple types of higher-order assemblies and we present crystalline arrays of MP20. When isolated in the absence of divalent cations, MP20 is solubilized predominantly in tetrameric form, whereas the presence of divalent cations during solubilization promotes the association of MP20 tetramers into higher-order species. This effect only occurs when divalent cations are present during solubilization but not when divalent cations are added to solubilized tetrameric MP20, suggesting that other factors may also be involved. When purified MP20 tetramers are reconstituted with native lens lipids in the presence of magnesium, MP20 forms two-dimensional (2D) crystals. A projection map at 18 A resolution calculated from negatively stained 2D crystals showed that the building block of the crystal is an octamer consisting of two tetramers related to each other by 2-fold symmetry. In addition to 2D crystals, reconstitution of MP20 with native lipids also produced a variety of large protein-lipid complexes, and we present three-dimensional (3D) reconstructions of the four most abundant of these complexes in negative stain. The various complexes formed by MP20 most likely reflect the many ways in which tetraspanins can interact with each other to allow formation of TEMs.