Fibulin-1 suppression of fibronectin-regulated cell adhesion and motility

Identification of a fibronectin-binding protein signature associated with idiopathic pulmonary fibrosis

The extracellular matrix (ECM) is a critical component of tissue where it provides structural and signaling support to cells. Its dysregulation and accumulation lead to fibrosis, a major clinical challenge underlying many diseases that currently has little effective treatment. An understanding of the key molecular initiators of fibrosis would be both diagnostically useful and provide potential targets for therapeutics. The ECM protein fibronectin (FN) is upregulated in fibrotic conditions and other ECM proteins depend on assembly of a FN foundational ECM for their matrix incorporation. We used cell culture and in vivo models to investigate the role of FN in the progression of lung fibrosis. We confirmed that normal human lung fibroblasts (NHLFs) treated with transforming growth factor-beta (TGF-β) to stimulate fibrotic gene expression significantly increased both FN expression and its assembly into a matrix. We found that levels of alternatively spliced EDA and EDB exons were proportional to the increase in total FN RNA and protein showing that inclusion of these exons is not enhanced by TGF-β stimulation. RNA-sequencing identified 43 core matrisome genes that were significantly up- or down-regulated by TGF-β treatment and a Luminex immunoassay demonstrated increased levels of ECM proteins in conditioned medium of TGF-β-treated NHLFs. Interestingly, among the regulated core matrisome genes, 16 encode known FN-binding proteins and, of these, insulin-like growth factor binding protein 3 (IGFBP3) was most highly up-regulated. To link the NHLF results with in vivo disease, we analyzed lung tissue and bronchoalveolar lavage fluid from bleomycin-treated mice and found dramatically higher levels of FN and the FN-binding proteins IGFBP3, tenascin-C, and type I collagen in fibrotic conditions compared to controls. Altogether, our data identify a set of FN-binding proteins whose upregulation is characteristic of IPF and suggest that FN provides the foundational matrix for deposition of these proteins as fibrosis develops.

Multiomics Analysis Unravels Alteration in Molecule and Pathways Involved in Nondiabetic Chronic Wounds

The prevalence of chronic wounds (CW) continues to grow. A thorough knowledge of the mechanism of CW formation remains elusive due to a lack of relevant studies. Furthermore, most previous studies concentrated on diabetic ulcers with relatively few investigations on other types. We performed this multiomics study to investigate the proteomic and metabolomic changes in wound and surrounding tissue from a cohort containing 13 patients with nondiabetic CW. Differentially expressed proteins (DEPs) and metabolites (DEMs) were filtered out and analyzed through multiomic profiling. The DEPs were further confirmed with the use of parallel reaction monitoring. Compared with the surrounding tissue, there were 82 proteins and 214 metabolites altered significantly in wound tissue. The DEPs were mainly enriched in focal adhesion (FA), extracellular matrix-receptor interaction (ERI), and the PI3K-Akt (PA) signaling pathway. Moreover, the DEMs were significantly enriched in amino sugar and nucleotide sugar metabolism and biosynthesis of nucleotide sugar pathways. In correlation analysis, we discovered that the PA signaling pathway, as well as its upstream and downstream pathways, coenriched some DEPs and DEMs. Additionally, we found that FBLN1, FBLN5, and EFEMP1 (FBLN3) proteins dramatically elevated in wound tissue and connected with the above signaling pathways. This multiomics study found that changes in FA, ERI, and PA signaling pathways had an impact on the cellular activities and functions of wound tissue cells. Additionally, increased expression of those proteins in wound tissue may inhibit vascular and skin cell proliferation and degrade the extracellular matrix, which may be one of the causes of CW formation.

The role of fibrosis in cardiomyopathies: An opportunity to develop novel biomarkers of disease activity

Cardiomyopathies encompass a spectrum of heart disorders with diverse causes and presentations. Fibrosis stands out as a shared hallmark among various cardiomyopathies, reflecting a common thread in their pathogenesis. This prevalent fibrotic response is intricately linked to the consequences of dysregulated extracellular matrix (ECM) remodeling, emphasizing its significance in the development and progression the disease. This review explores the ECM involvement in various cardiomyopathies and its impact on myocardial stiffness and fibrosis. Additionally, we discuss the potential of ECM fragments as early diagnosis, prognosis, and risk stratification. Biomarkers deriving from turnover of collagens and other ECM proteins hold promise in clinical applications. We outline current clinical management, future directions, and the potential for personalized ECM-targeted therapies with specific focus on microRNAs. In summary, this review examines the role of the fibrosis in cardiomyopathies, highlighting the potential of ECM-derived biomarkers in improving disease management with implications for precision medicine.

Stop codon variant in EFEMP1 is associated with primary open-angle glaucoma due to impaired regulation of aqueous humor outflow

It is known that the actin cytoskeleton and its associated cellular interactions in the trabecular meshwork (TM) and juxtacanalicular tissues mainly contribute to the formation of resistance to aqueous outflow of the eye. Fibulin-3, encoded by EFEMP1 gene, has a role in extracellular matrix (ECM) modulation, and interacts with enzymatic ECM regulators, but the effects of fibulin-3 on TM cells has not been explored. Here, we report a stop codon variant (c.T1480C, p.X494Q) of EFEMP1 that co-segregates with primary open angle glaucoma (POAG) in a Chinese pedigree. In the human TM cells, overexpression of wild-type fibulin-3 reduced intracellular actin stress fibers formation and the extracellular fibronectin levels by inhibiting Rho/ROCK signaling. TGFβ1 up-regulated fibulin-3 protein levels in human TM cells by activating Rho/ROCK signaling. In rat eyes, overexpression of wild-type fibulin-3 decreased the intraocular pressure and the fibronectin expression of TM, however, overexpression of mutant fibulin-3 (c.T1480C, p.X494Q) showed opposite effects in cells and rat eyes. Taken together, the EFEMP1 variant may impair the regulatory capacity of fibulin-3 which has a role for modulating the cell contractile activity and ECM synthesis in TM cells, and in turn may maintain normal resistance of aqueous humor outflow. This study contributes to the understanding of the important role of fibulin-3 in TM pathophysiology and provides a new possible POAG therapeutic approach.

Secretome profiling of Artemisia absinthium extract-loaded polymeric nanoparticle-treated MCF-7 and MDA-MB-231 revealed perturbation in microtubule assembly and cell migration

Introduction

Artemisia absinthium (wormwood) exhibits anticancer properties by inhibiting proliferation and causing cell death in breast cancer. Targeted drug delivery of A. absinthium nanoformulation using N-isopropyl acrylamide, N-vinyl pyrrolidone, and acrylic acid-based polymeric nanoparticles (NVA-AA NPs) was ensured by utilizing features of the tumor microenvironment, although their mechanism of action involved in cytotoxicity remains unknown.

Methods

The present study employed nano LC-MS/MS to identify differences in secretory protein expression associated with the treatment of breast cancer cell lines (MCF-7; MDA-MB-231) by NVA-AA NPs for the determination of affected pathways and easily accessible therapeutic targets. Different bioinformatics tools were used to identify signature differentially expressed proteins (DEPs) using survival analysis by GENT2 and correlation analysis between their mRNA expressions and sensitivity toward small-molecule drugs as well as immune cell infiltration by GSCA.

Results

Analysis by GENT2 revealed 22 signature DEPs with the most significant change in their expression regulation, namely, gelsolin, alpha-fetoprotein, complement component C3, C7, histone H2B type 1-K, histone H2A.Z, H2AX, heat shock cognate 71 kDa protein, heat shock 70 kDa protein 1-like, cytochrome c somatic, GTP-binding nuclear protein Ran, tubulin beta chain, tubulin alpha-1B chain, tubulin alpha-1C chain, phosphoglycerate mutase 1, kininogen 1, carboxypeptidase N catalytic chain, fibulin-1, peroxiredoxins 4, lactate dehydrogenase C, SPARC, and SPARC-like protein 1. Correlation analysis between their mRNA expressions versus immune cell infiltrates showed a positive correlation with antitumor immune response elicited by these NPs as well as a correlation with drug response shown by the GDSC and CTRP drugs in different cancer cells.

Discussion

Our results suggest that NVA-AA NPs were able to invade the tumor microenvironment; transformed the communication network between the cancer cells; affected potential drivers of microtubular integrity, nucleosome assembly, and cell cycle; and eventually caused cell death.

Insights from 4D Label-Free Proteomic Analysis into Variation of Milk Fat Globule Membrane Proteins of Human Milk Associated with Infant's Gender

Milk fat globule membrane (MFGM) protein profiles of breast milk collected from women in northeast China with male or female babies were investigated using a four-dimensional (4D) label-free proteomic technique. Altogether, 2538 proteins were detected and quantified and 249 were differentially expressed, with 198 decreased proteins compared to the samples of mothers with female babies. Different proteins associated with infant's gender were principally located in nuclear. The differentially expressed proteins were mainly involved in gene ontology (GO) functions of the cellular process, binding, and cell and found to be distributed in lipid-related biological processes and molecular functions to a large extent. The pathway of neurodegeneration-multiple disease ranked top for the altered proteins. The screened proteins were observed to contain some proteins related to typical functions of immunity, lipid metabolism, digestion, and growth and development. 114 proteins formed a relatively compact network (269 interactions) and dolichyl-diphospho-oligosaccharide-protein glycosyltransferase subunit 2 interacted the most with other proteins as the hub protein. MFGM proteins of breast milk were affected by the sex of offspring, and these findings may provide useful information for reasonable adjustments of infant formula powder specifically for boys or girls in the market.

Serum proteome profiling of naturally acquired Babesia rossi infection in dogs

Babesiosis is a disease of significant medically and veterinary importance with worldwide distribution. It is caused by intra-erythrocyte protozoal parasites, with Babesia rossi causing the most severe clinical signs of all the large Babesia parasites infecting dogs. The disease can be clinically classified into uncomplicated and complicated forms with a wide range of clinical presentations from a mild, subclinical illness to complicated forms and death. The aim of this study was to assess serum proteomic profiles from dogs with babesiosis and healthy dogs using a label-based proteomics approach. Altogether 32 dogs naturally infected with B. rossi (subdivided into 18 uncomplicated cases and 14 complicated cases of babesiosis) and 20 healthy dogs were included. There were 78 proteins with significantly different abundances between the three groups of dogs. Elucidation of proteins and pathways involved in canine babesiosis caused by B. rossi have revealed key differences associated with haemostasis, innate immune system, lipid metabolism and inflammation. Shotgun proteomic profiling allowed identification of potential serum biomarkers for differentiation of disease severity in canine babesiosis caused by B. rossi. These findings may be applicable to the study of host-parasite interactions and the development of novel therapeutic targets.

Genetics and Molecular Basis of Congenital Heart Defects in Down Syndrome: Role of Extracellular Matrix Regulation

Down syndrome (DS), a complex disorder that is caused by the trisomy of chromosome 21 (Hsa21), is a major cause of congenital heart defects (CHD). Interestingly, only about 50% of individuals with Hsa21 trisomy manifest CHD. Here we review the genetic basis of CHD in DS, focusing on genes that regulate extracellular matrix (ECM) organization. The overexpression of Hsa21 genes likely underlies the molecular mechanisms that contribute to CHD, even though the genes responsible for CHD could only be located in a critical region of Hsa21. A role in causing CHD has been attributed not only to protein-coding Hsa21 genes, but also to genes on other chromosomes, as well as miRNAs and lncRNAs. It is likely that the contribution of more than one gene is required, and that the overexpression of Hsa21 genes acts in combination with other genetic events, such as specific mutations or polymorphisms, amplifying their effect. Moreover, a key function in determining alterations in cardiac morphogenesis might be played by ECM. A large number of genes encoding ECM proteins are overexpressed in trisomic human fetal hearts, and many of them appear to be under the control of a Hsa21 gene, the RUNX1 transcription factor.

Cathepsin F and Fibulin-1 as novel diagnostic biomarkers for brain metastasis of non-small cell lung cancer

Background

The lack of non-invasive methods for detection of early micro-metastasis is a major cause of the poor prognosis of non-small cell lung cancer (NSCLC) brain metastasis (BM) patients. Herein, we aimed to identify circulating biomarkers based on proteomics for the early diagnosis and monitoring of patients with NSCLC BM.

Methods

Upregulated proteins were detected by secretory proteomics in the animal-derived high brain metastatic lung cancer cell line. A well-designed study composed of three independent cohorts was then performed to verify these blood-based protein biomarkers: the serum discovery and verification cohorts (n = 80; n = 459), and the tissue verification cohort (n = 76). Logistic regression was used to develop a diagnostic biomarker panel. Model validation cohort (n = 160) was used to verify the stability of the constructed predictive model. Changes in serum Cathepsin F (CTSF) levels of patients were tracked to monitor the treatment response. Progression-free survival (PFS) and overall survival (OS) were analysed to assess their prognostic relevance.

Results

CTSF and Fibulin-1 (FBLN1) levels were specifically upregulated in sera and tissues of patients with NSCLC BM compared with NSCLC without BM and primary brain tumour. The combined diagnostic performance of CTSF and FBLN1 was superior to their individual ones. CTSF serum changes were found to reflect the therapeutic response of patients with NSCLC BM and the trends of progression were detected earlier than the magnetic resonance imaging changes. Elevated expression of CTSF in NSCLC BM tissues was associated with poor PFS, and was found to be an independent prognostic factor.

Conclusions

We report a novel blood-based biomarker panel for early diagnosis, monitoring of therapeutic response, and prognostic evaluation of patients with NSCLC BM.

EGFR-Dependent Extracellular Matrix Protein Interactions Might Light a Candle in Cell Behavior of Non-Small Cell Lung Cancer

Lung cancer remains the leading cause of cancer-related death and is associated with a poor prognosis. Lung cancer is divided into 2 main types: the major in incidence is non-small cell lung cancer (NSCLC) and the minor is small cell lung cancer (SCLC). Although NSCLC progression depends on driver mutations, it is also affected by the extracellular matrix (ECM) interactions that activate their corresponding signaling molecules in concert with integrins and matrix metalloproteinases (MMPs). These signaling molecules include cytoplasmic kinases, small GTPases, adapter proteins, and receptor tyrosine kinases (RTKs), particularly the epidermal growth factor receptor (EGFR). In NSCLC, the interplay between ECM and EGFR regulates ECM stiffness, angiogenesis, survival, adhesion, migration, and metastasis. Furthermore, some tumor-promoting ECM components (e.g., glycoproteins and proteoglycans) enhance activation of EGFR and loss of PTEN. On the other hand, other tumor-suppressing glycoproteins and -proteoglycans can inhibit EGFR activation, suppressing cell invasion and migration. Therefore, deciphering the molecular mechanisms underlying EGFR and ECM interactions might provide a better understanding of disease pathobiology and aid in developing therapeutic strategies. This review critically discusses the crosstalk between EGFR and ECM affecting cell behavior of NSCLC, as well as the involvement of ECM components in developing resistance to EGFR inhibition.

Protein Ligands in the Secretome of CD36+ Fibroblasts Induce Growth Suppression in a Subset of Breast Cancer Cell Lines

Simple Summary

Human breast cancers are not fully autonomous. They are dependent on nutrients and growth-promoting signals provided by stromal cells. In order to instruct the surrounding cells to provide essential growth factors, cancer cells co-opt normal signaling molecules and mechanisms. To inhibit or potentially reverse tumor growth, our goal is to emulate this signaling and reprogram the microenvironment. For example, in a healthy mammary gland, fibroblasts (FBs) overexpress CD36; and the downregulation of CD36 is one of the hallmarks of cancer-associated FBs. Therefore, in this project, we hypothesized that signaling from CD36⁺ FBs could cause growth suppression in a subset of breast cancer cell lines. We then designed a series of experiments to validate this growth suppression and identified responsible secreted factors by the CD36⁺ FBs. These experiments suggested that three protein ligands are primarily responsible for growth suppression in a subset of breast cancer cell lines.

Abstract

Reprogramming the tumor stroma is an emerging approach to circumventing the challenges of conventional cancer therapies. This strategy, however, is hampered by the lack of a specific molecular target. We previously reported that stromal fibroblasts (FBs) with high expression of CD36 could be utilized for this purpose. These studies are now expanded to identify the secreted factors responsible for tumor suppression. Methodologies included 3D colonies, fluorescent microscopy coupled with quantitative techniques, proteomics profiling, and bioinformatics analysis. The results indicated that the conditioned medium (CM) of the CD36⁺ FBs caused growth suppression via apoptosis in the triple-negative cell lines of MDA-MB-231, BT549, and Hs578T, but not in the ERBB2⁺ SKBR3. Following the proteomics and bioinformatic analysis of the CM of CD36⁺ versus CD36⁻ FBs, we determined KLF10 as one of the transcription factors responsible for growth suppression. We also identified FBLN1, SLIT3, and PENK as active ligands, where their minimum effective concentrations were determined. Finally, in MDA-MB-231, we showed that a mixture of FBLN1, SLIT3, and PENK could induce an amount of growth suppression similar to the CM of CD36⁺ FBs. In conclusion, our findings suggest that these ligands, secreted by CD36⁺ FBs, can be targeted for breast cancer treatment.

Act of fibulin-1 in preeclamptic patients: can it be a predictive marker?

Preeclampsia is one of the leading causes of maternal-neonatal morbidity and mortality, especially in developed and developing countries. Incidence of preeclampsia differs in accordance with parity, race, age, geography, and concomitant diseases. The role of placental implantation and risk factors was elucidated precisely. Antenatal care, use of medications, change in lifestyle, and nutritional supplementation were investigated for the prevention or decrease the complications; however, to date, there has not exposed a proper approach for prevention and prediction. The trigger mechanism or circumstance is still debate. Placental development especially spiral artery remodeling might be supposed to be the accused primary site of preeclampsia. Extracellular matrix proteins play a crucial role in implantation. Fibulin is one of these proteins which represents an association with matrix proteins, basement membranes, and elastic fibers. Fibulins are mainly functioning in the remodeling of tissues especially blood vessels, endocardial cushion, the mesenchymal, and connective tissue of several organs including heart, lung, intestine, kidneys, and liver. Several diseases were associated with altered fibulin levels. We aimed to examine fibulin-1 levels in preeclamptic patients and to focus on the possible role of fibulin-1 in preeclampsia.

MATERIAL AND METHOD

A prospective observational, case-control study was achieved. Patients diagnosed with preeclampsia and healthy controls were recruited in the study. Patients' demographic features, perinatal outcomes, complications, obstetrics doppler ultrasonographic evaluations, laboratory results, and serum fibulin-1 levels were reviewed. The comparison of the groups was determined statistically. Correlation analysis and multivariate logistic analysis were calculated. The receiver operating characteristic (ROC) curve was used to indicate fibulin-1 levels for the prediction of preeclampsia.

RESULTS

A total of 36 healthy pregnant and 38 preeclamptic patients were included in the study. Comparison of the groups with age, gravidity, BMI, APGAR scores, birth weight did not differ significantly. Kidney and liver function tests and complete hemogram parameters did not have a clinically important difference. Fibulin-1 levels were significantly lower in patients with preeclampsia. The ROC curve for fibulin-1 for predicting the preeclampsia risk was analyzed. The area under the ROC curves was 0.682 (95% CI [0.560-0.804, p < .007) for fibulin-1. The optimal cutoff value of fibulin-1 for detecting preeclampsia was ≤ 27.81 ng/ml, at which the sensitivity was 61.1% and specificity was 63.2 %.

CONCLUSION

Fibulin-1 levels could be a beneficial marker for preeclampsia diagnosis and prediction. It might have a role in the etiopathology of preeclampsia, due to its function in the extracellular matrix.

Genetic Investigation of Inverse Psoriasis

Inverse psoriasis is considered to be a rare variant of plaque-type psoriasis and is associated with significantly impaired quality of life. Clinical manifestations and treatment options are somewhat different for each subtype. Identifying genetic variants that contribute to the susceptibility of different types of psoriasis might improve understanding of the etiology of the disease. Since we have no current knowledge about the genetic background of inverse psoriasis, whole exome sequencing was used to comprehensively assess genetic variations in five patients with exclusively inverse lesions. We detected six potentially pathogenic rare (MAF < 0.01) sequence variants that occurred in all investigated patients. The corresponding mutated genes were FN1, FBLN1, MYH7B, MST1R, RHOD, and SCN10A. Several mutations identified in this study are known to cause disease, but roles in psoriasis or other papulosquamous diseases have not previously been reported. Interestingly, potentially causative variants of established psoriasis-susceptibility genes were not identified. These outcomes are in agreement with our hypothesis that the inverse subtype is a different entity from plaque-type psoriasis.

Quantitative Proteomic Approach for Discriminating Major Depressive Disorder and Bipolar Disorder by Multiple Reaction Monitoring-Mass Spectrometry

Because major depressive disorder (MDD) and bipolar disorder (BD) manifest with similar symptoms, misdiagnosis is a persistent issue, necessitating their differentiation through objective methods. This study was aimed to differentiate between these disorders using a targeted proteomic approach. Multiple reaction monitoring-mass spectrometry (MRM-MS) analysis was performed to quantify protein targets regarding the two disorders in plasma samples of 270 individuals (90 MDD, 90 BD, and 90 healthy controls (HCs)). In the training set (72 MDD and 72 BD), a generalizable model comprising nine proteins was developed. The model was evaluated in the test set (18 MDD and 18 BD). The model demonstrated a good performance (area under the curve (AUC) >0.8) in discriminating MDD from BD in the training (AUC = 0.84) and test sets (AUC = 0.81) and in distinguishing MDD from BD without current hypomanic/manic/mixed symptoms (90 MDD and 75 BD) (AUC = 0.83). Subsequently, the model demonstrated excellent performance for drug-free MDD versus BD (11 MDD and 10 BD) (AUC = 0.96) and good performance for MDD versus HC (AUC = 0.87) and BD versus HC (AUC = 0.86). Furthermore, the nine proteins were associated with neuro, oxidative/nitrosative stress, and immunity/inflammation-related biological functions. This proof-of-concept study introduces a potential model for distinguishing between the two disorders.

Therapeutic targets in lung tissue remodelling and fibrosis

Structural changes involving tissue remodelling and fibrosis are major features of many pulmonary diseases, including asthma, chronic obstructive pulmonary disease (COPD) and idiopathic pulmonary fibrosis (IPF). Abnormal deposition of extracellular matrix (ECM) proteins is a key factor in the development of tissue remodelling that results in symptoms and impaired lung function in these diseases. Tissue remodelling in the lungs is complex and differs between compartments. Some pathways are common but tissue remodelling around the airways and in the parenchyma have different morphologies. Hence it is critical to evaluate both common fibrotic pathways and those that are specific to different compartments; thereby expanding the understanding of the pathogenesis of fibrosis and remodelling in the airways and parenchyma in asthma, COPD and IPF with a view to developing therapeutic strategies for each. Here we review the current understanding of remodelling features and underlying mechanisms in these major respiratory diseases. The differences and similarities of remodelling are used to highlight potential common therapeutic targets and strategies. One central pathway in remodelling processes involves transforming growth factor (TGF)-β induced fibroblast activation and myofibroblast differentiation that increases ECM production. The current treatments and clinical trials targeting remodelling are described, as well as potential future directions. These endeavours are indicative of the renewed effort and optimism for drug discovery targeting tissue remodelling and fibrosis.

Fibronectin as a multiregulatory molecule crucial in tumor matrisome: from structural and functional features to clinical practice in oncology

Deciphering extracellular matrix (ECM) composition and architecture may represent a novel approach to identify diagnostic and therapeutic targets in cancer. Among the ECM components, fibronectin and its fibrillary assembly represent the scaffold to build up the entire ECM structure, deeply affecting its features. Herein we focus on this extraordinary protein starting from its complex structure and defining its role in cancer as prognostic and theranostic marker.

R-catcher, a potent molecular tool to unveil the arginylome

Protein arginylation is a critical regulator of a variety of biological processes. The ability to uncover the global arginylation pattern and its associated signaling pathways would enable us to identify novel disease targets. Here, we report the development of a tool able to capture the N-terminal arginylome. This tool, termed R-catcher, is based on the ZZ domain of p62, which was previously shown to bind N-terminally arginylated proteins. Mutating the ZZ domain enhanced its binding specificity and affinity for Nt-Arg. R-catcher pulldown coupled to LC-MS/MS led to the identification of 59 known and putative arginylated proteins. Among these were a subgroup of novel ATE1-dependent arginylated ER proteins that are linked to diverse biological pathways, including cellular senescence and vesicle-mediated transport as well as diseases, such as Amyotrophic Lateral Sclerosis and Alzheimer's disease. This study presents the first molecular tool that allows the unbiased identification of arginylated proteins, thereby unlocking the arginylome and provide a new path to disease biomarker discovery.

Exploration of identifying novel serum biomarkers for malignant mesothelioma using iTRAQ combined with 2D-LC-MS/MS

Malignant mesothelioma (MM) is an aggressive cancer linked to asbestos exposure. Its poor prognosis makes early diagnosis extremely important, which would provide an opportunity for early treatment and potentially changing outcomes. This study aimed to explore the underlying mechanisms of MM and discover novel noninvasive biomarkers for the diagnosis of malignant mesothelioma. Using Isobaric tags for relative and absolute quantitation (iTRAQ) combined with two-dimensional liquid chromatography/tandem mass spectrometry (2D LC-MS/MS), a total of 145 differentially expressed serum proteins were identified between MM patients and healthy controls. The identified proteins were further analyzed by bioinformatics, out of which three candidate biomarkers (Filamin A (FLNA), Fibulin 1 (FBLN1) and Thrombospondin-1 (TSP-1)) were validated in large cohorts of patients with asbestos-related diseases including MM patients by ELISA assay. Receiver operating characteristic (ROC) curve analysis showed that serum FLNA, FBLN1 and TSP-1 had high diagnostic values in distinguishing MM patients from healthy controls, individuals with asbestos exposure (AE), and patients with pleural plaques (PP) or asbestosis. Meanwhile, serum FBLN1 and TSP-1 possessed good diagnostic values in distinguishing asbestosis patients from healthy controls and individuals with AE. The combination of FLNA, FBLN1, and TSP-1 proteins had higher sensitivity and specificity in discriminating patients with MM, PP and asbestosis. Our findings indicated that analysis of serum proteome using iTRAQ is a feasible strategy for biomarker discovery, and serum FLNA, FBLN1 and TSP-1 may be promising candidates for diagnosis of malignant mesothelioma and screening of at-risk individuals.

APP Binds to the EGFR Ligands HB-EGF and EGF, Acting Synergistically with EGF to Promote ERK Signaling and Neuritogenesis

The amyloid precursor protein (APP) is a transmembrane glycoprotein central to Alzheimer's disease (AD) with functions in brain development and plasticity, including in neurogenesis and neurite outgrowth. Epidermal growth factor (EGF) and heparin-binding EGF-like growth factor (HB-EGF) are well-described neurotrophic and neuromodulator EGFR ligands, both implicated in neurological disorders, including AD. Pro-HB-EGF arose as a putative novel APP interactor in a human brain cDNA library yeast two-hybrid screen. Based on their structural and functional similarities, we first aimed to verify if APP could bind to (HB-)EGF proforms. Here, we show that APP interacts with these two EGFR ligands, and further characterized the effects of APP-EGF interaction in ERK activation and neuritogenesis. Yeast co-transformation and co-immunoprecipitation assays confirmed APP interaction with HB-EGF. Co-immunoprecipitation also revealed that APP binds to cellular pro-EGF. Overexpression of HB-EGF in HeLa cells, or exposure of SH-SY5Y cells to EGF, both resulted in increased APP protein levels. EGF and APP were observed to synergistically activate the ERK pathway, crucial for neuronal differentiation. Immunofluorescence analysis of cellular neuritogenesis in APP overexpression and EGF exposure conditions confirmed a synergistic effect in promoting the number and the mean length of neurite-like processes. Synergistic ERK activation and neuritogenic effects were completely blocked by the EGFR inhibitor PD 168393, implying APP/EGF-induced activation of EGFR as part of the mechanism. This work shows novel APP protein interactors and provides a major insight into the APP/EGF-driven mechanisms underlying neurite outgrowth and neuronal differentiation, with potential relevance for AD and for adult neuroregeneration.

Mechano-responsiveness of fibrillar adhesions on stiffness-gradient gels

Fibrillar adhesions are important structural and adhesive components in fibroblasts, and are required for fibronectin fibrillogenesis. While nascent and focal adhesions are known to respond to mechanical cues, the mechanoresponsive nature of fibrillar adhesions remains unclear. Here, we used ratiometric analysis of paired adhesion components to determine an appropriate fibrillar adhesion marker. We found that active α5β1-integrin exhibits the most definitive fibrillar adhesion localization compared to other proteins, such as tensin-1, reported to be in fibrillar adhesions. To elucidate the mechanoresponsiveness of fibrillar adhesions, we designed a cost-effective and reproducible technique to fabricate physiologically relevant stiffness gradients on thin polyacrylamide (PA) hydrogels, embedded with fluorescently labelled beads. We generated a correlation curve between bead density and hydrogel stiffness, thus enabling a readout of stiffness without the need for specialized knowhow, such as atomic force microscopy (AFM). We find that stiffness promotes growth of fibrillar adhesions in a tensin-1-dependent manner. Thus, the formation of these extracellular matrix-depositing structures is coupled to the mechanical parameters of the cell environment and may enable cells to fine-tune their matrix environment in response to changing physical conditions.

Secretory proteostasis of the retinal pigmented epithelium: Impairment links to age-related macular degeneration

Secretory proteostasis integrates protein synthesis, processing, folding and trafficking pathways that are essential for efficient cellular secretion. For the retinal pigment epithelium (RPE), secretory proteostasis is of vital importance for the maintenance of the structural and functional integrity of apical (photoreceptors) and basal (Bruch's membrane/choroidal blood supply) sides of the environment it resides in. This integrity is achieved through functions governed by RPE secreted proteins, which include extracellular matrix modelling/remodelling, angiogenesis and immune response modulation. Impaired RPE secretory proteostasis affects not only the extracellular environment, but leads to intracellular protein aggregation and ER-stress with subsequent cell death. Ample recent evidence implicates dysregulated proteostasis as a key factor in the development of age-related macular degeneration (AMD), the leading cause of blindness in the developed world, and research aiming to characterise the roles of various proteins implicated in AMD-associated dysregulated proteostasis unveiled unexpected facets of the mechanisms involved in degenerative pathogenesis. This review analyses cellular processes unveiled by the study of the top 200 transcripts most abundantly expressed by the RPE/choroid in the light of the specialised secretory nature of the RPE. Functional roles of these proteins and the mechanisms of their impaired secretion, due to age and genetic-related causes, are analysed in relation to AMD development. Understanding the importance of RPE secretory proteostasis in relation to maintaining retinal health and how it becomes impaired in disease is of paramount importance for the development and assessment of future therapeutic advancements involving gene and cell therapies.

ADAMTS-1 and syndecan-4 intersect in the regulation of cell migration and angiogenesis

ADAMTS-1 is an extracellular protease with critical roles in organogenesis and angiogenesis. Here we demonstrate a functional convergence of ADAMTS-1 and the transmembrane heparan sulfate proteoglycan syndecan-4 in influencing adhesion, migration and angiogenesis. Knockdown of ADAMTS-1 in endothelial cells resulted in a parallel reduction in cell surface syndecan-4, attributable to increased matrix metalloproteinase-9 (MMP9) activity. Knockdown of either ADAMTS-1 or syndecan-4 increased cellular responses to vascular endothelial growth factor A isoform VEGFA₁₆₄, and increased ex vivo aortic ring microvessel sprouting. On fibronectin, knockdown of either protein enhanced migration and promoted formation of long α5 integrin-containing fibrillar adhesions. However, integrin α5 null cells still showed increased migration in response to ADAMTS-1 and syndecan-4 siRNA treatment. Plating of naïve endothelial cells on cell-conditioned matrix from ADAMTS-1 and syndecan-4 knockdown cells demonstrated that the altered adhesive behaviour was matrix dependent, and this correlated with a lack of expression of fibulin-1: an extracellular matrix co-factor for ADAMTS-1 that is known to inhibit migration. These findings support the notion that ADAMTS-1 and syndecan-4 are functionally interconnected in regulating cell migration and angiogenesis, via collaboration with MMP9 and fibulin-1.

This article has an associated First Person interview with the first author of the paper.

Summary: ADAMTS-1 and syndecan-4 collaborate to regulate cell adhesion, migration and integrin α5 trafficking, and to sequester VEGFA₁₆₄, inhibiting angiogenesis.

Unravelling the genetic basis of schizophrenia and bipolar disorder with GWAS: A systematic review

OBJECTIVES

To systematically review findings of GWAS in schizophrenia (SZ) and in bipolar disorder (BD); and to interpret findings, with a focus on identifying independent replications.

METHOD

PubMed search, selection and review of all independent GWAS in SZ or BD, published since March 2011, i.e. studies using non-overlapping samples within each article, between articles, and with those of the previous review (Li et al., 2012).

RESULTS

From the 22 GWAS included in this review, the genetic associations surviving standard GWAS-significance were for genetic markers in the regions of ACSL3/KCNE4, ADCY2, AMBRA1, ANK3, BRP44, DTL, FBLN1, HHAT, INTS7, LOC392301, LOC645434/NMBR, LOC729457, LRRFIP1, LSM1, MDM1, MHC, MIR2113/POU3F2, NDST3, NKAPL, ODZ4, PGBD1, RENBP, TRANK1, TSPAN18, TWIST2, UGT1A1/HJURP, WHSC1L1/FGFR1 and ZKSCAN4. All genes implicated across both reviews are discussed in terms of their function and implication in neuropsychiatry.

CONCLUSION

Taking all GWAS to date into account, AMBRA1, ANK3, ARNTL, CDH13, EFHD1 (albeit with different alleles), MHC, PLXNA2 and UGT1A1 have been implicated in either disorder in at least two reportedly non-overlapping samples. Additionally, evidence for a SZ/BD common genetic basis is most strongly supported by the implication of ANK3, NDST3, and PLXNA2.

The expression level of fibulin-2 in the circulating RNA (ctRNA) of epithelial tumor cells of peripheral blood and tumor tissue of patients with metastatic lung cancer

The Fibulins are a recently discovered family of extracellular matrix proteins. In this study, expression levels of the fibulin-2 (FBLN2) gene and its role in the formation of different metastatic foci were investigated in lung cancer patients. We analyzed 106 lung cancer patients and eight paraffin-embedded tissues, and 27 ethnical-, age- and sex-matched healthy controls for expression levels of the FBLN2 gene. cDNAs obtained from the enriched epithelial cells of peripheral blood lymphocytes and tumor tissues of patients were amplified with specific primers for the target FBLN2 gene and HPRT1 housekeeping gene using quantitative real-time polymerase chain reaction. FBLN2 gene expression levels of the enriched epithelial cells of peripheral blood lymphocytes were found to be decreased approximately twofold in all subsets of patients compared to healthy controls. Our results indicate a significant difference between patient subgroups and controls [F(4.124) = 14.846, p0.05] among patient subgroups: bone metastases versus non-metastatic groups (p = 0.997), bone versus brain metastases (p = 0994), bone metastases versus two primary tumors (p = 0.999), brain metastases versus two primary tumors (p = 0.999), brain metastases versus non-metastatic (p = 0.755), non-metastatic versus two primary tumors (p = 0.996), non-metastatic versus all other metastatic patients (p = 0.731). Moreover, we found a 50-fold upregulation of FBLN2 gene expression in paraffin-embedded tissues compared with the enriched epithelial cells of peripheral blood lymphocytes of patients. In the study, the enriched epithelial cells of peripheral blood lymphocytes of decreased FBLN2 expression was found to be correlated with metastasis. The fibulin-2 molecules might induce the metastatic potential through interaction with the other molecules in the microenvironment, nevertheless, it is needed further research whether the importance of FBLN2 on lung cancer oncogenesis and as a biomarker for metastatic lung cancer.

Extracellular Interactions between Fibulins and Transforming Growth Factor (TGF)-β in Physiological and Pathological Conditions

Transforming growth factor (TGF)-β is a multifunctional peptide growth factor that has a vital role in the regulation of cell growth, differentiation, inflammation, and repair in a variety of tissues, and its dysregulation mediates a number of pathological conditions including fibrotic disorders, chronic inflammation, cardiovascular diseases, and cancer progression. Regulation of TGF-β signaling is multifold, but one critical site of regulation is via interaction with certain extracellular matrix (ECM) microenvironments, as TGF-β is primarily secreted as a biologically inactive form sequestrated into ECM. Several ECM proteins are known to modulate TGF-β signaling via cell–matrix interactions, including thrombospondins, SPARC (Secreted Protein Acidic and Rich in Cystein), tenascins, osteopontin, periostin, and fibulins. Fibulin family members consist of eight ECM glycoproteins characterized by a tandem array of calcium-binding epidermal growth factor-like modules and a common C-terminal domain. Fibulins not only participate in structural integrity of basement membrane and elastic fibers, but also serve as mediators for cellular processes and tissue remodeling as they are highly upregulated during embryonic development and certain disease processes, especially at the sites of epithelial–mesenchymal transition (EMT). Emerging studies have indicated a close relationship between fibulins and TGF-β signaling, but each fibulin plays a different role in a context-dependent manner. In this review, regulatory interactions between fibulins and TGF-β signaling are discussed. Understanding biological roles of fibulins in TGF-β regulation may introduce new insights into the pathogenesis of some human diseases.

Plasminogen activator inhibitor-1 and tenascin-C secreted by equine mesenchymal stromal cells stimulate dermal fibroblast migration in vitro and contribute to wound healing in vivo

BACKGROUND

Impaired cutaneous wound healing is common in humans, and treatments are often ineffective. Based on the significant emotional and economic burden of impaired wound healing, innovative therapies are needed. The potential of mesenchymal stromal cell (MSC)-secreted factors to treat cutaneous wounds is an active area of research that is in need of refinement before effective clinical trials can be initiated. The aims of the present study were to (i) study which MSC-secreted factors stimulate dermal fibroblast (DF) migration in vitro and (ii) evaluate the potential of these factors to promote wound healing in vivo.

METHODS

To this end, MSCs were isolated from the peripheral blood of healthy horses, a physiologically relevant large animal model appropriate for translational wound-healing studies. Conditioned medium (CM) from cultured equine MSCs was analyzed using liquid chromatography-mass spectrophotometry (LC-MS/MS) to identify secreted proteins of interest. Double-stranded RNA-mediated interference (RNAi) was used to silence the genes encoding selected proteins, and the effects of CM from these transfected MSCs on migration of cultured equine DF cells in vitro and full-thickness wounds in mice were evaluated.

RESULTS

We found that MSC-derived plasminogen activator inhibitor-1 (PAI-1) and tenascin-C significantly increased DF migration in vitro and improved wound healing in vivo by decreasing time to wound closure.

DISCUSSION

These results suggest that in a complex wound environment, MSC-secreted factors PAI-1 and tenascin-C contribute to the positive effect of therapeutically applied MSC CM on wound healing.

FK506-binding protein 10 (FKBP10) regulates lung fibroblast migration via collagen VI synthesis

Background

In idiopathic pulmonary fibrosis (IPF), fibroblasts gain a more migratory phenotype and excessively secrete extracellular matrix (ECM), ultimately leading to alveolar scarring and progressive dyspnea. Here, we analyzed the effects of deficiency of FK506-binding protein 10 (FKBP10), a potential IPF drug target, on primary human lung fibroblast (phLF) adhesion and migration.

Methods

Using siRNA, FKBP10 expression was inhibited in phLF in absence or presence of 2ng/ml transforming growth factor-β1 (TGF-β1) and 0.1mM 2-phosphoascorbate. Effects on cell adhesion and migration were monitored by an immunofluorescence (IF)-based attachment assay, a conventional scratch assay, and single cell tracking by time-lapse microscopy. Effects on expression of key players in adhesion dynamics and migration were analyzed by qPCR and Western Blot. Colocalization was evaluated by IF microscopy and by proximity ligation assays.

Results

FKBP10 knockdown significantly attenuated adhesion and migration of phLF. Expression of collagen VI was decreased, while expression of key components of the focal adhesion complex was mostly upregulated. The effects on migration were 2-phosphoascorbate-dependent, suggesting collagen synthesis as the underlying mechanism. FKBP10 colocalized with collagen VI and coating culture dishes with collagen VI, and to a lesser extent with collagen I, abolished the effect of FKBP10 deficiency on migration.

Conclusions

These findings show, to our knowledge for the first time, that FKBP10 interacts with collagen VI and that deficiency of FKBP10 reduces phLF migration mainly by downregulation of collagen VI synthesis. The results strengthen FKBP10 as an important intracellular regulator of ECM remodeling and support the concept of FKBP10 as drug target in IPF.

Airway remodelling and inflammation in asthma are dependent on the extracellular matrix protein fibulin-1c

Asthma is a chronic inflammatory disease of the airways. It is characterized by allergic airway inflammation, airway remodelling, and airway hyperresponsiveness (AHR). Asthma patients, in particular those with chronic or severe asthma, have airway remodelling that is associated with the accumulation of extracellular matrix (ECM) proteins, such as collagens. Fibulin-1 (Fbln1) is an important ECM protein that stabilizes collagen and other ECM proteins. The level of Fbln1c, one of the four Fbln1 variants, which predominates in both humans and mice, is increased in the serum and airways fluids in asthma but its function is unclear. We show that the level of Fbln1c was increased in the lungs of mice with house dust mite (HDM)-induced chronic allergic airway disease (AAD). Genetic deletion of Fbln1c and therapeutic inhibition of Fbln1c in mice with chronic AAD reduced airway collagen deposition, and protected against AHR. Fbln1c-deficient (Fbln1c^-/- ) mice had reduced mucin (MUC) 5 AC levels, but not MUC5B levels, in the airways as compared with wild-type (WT) mice. Fbln1c interacted with fibronectin and periostin that was linked to collagen deposition around the small airways. Fbln1c^-/- mice with AAD also had reduced numbers of α-smooth muscle actin-positive cells around the airways and reduced airway contractility as compared with WT mice. After HDM challenge, these mice also had fewer airway inflammatory cells, reduced interleukin (IL)-5, IL-13, IL-33, tumour necrosis factor (TNF) and CXCL1 levels in the lungs, and reduced IL-5, IL-33 and TNF levels in lung-draining lymph nodes. Therapeutic targeting of Fbln1c reduced the numbers of GATA3-positive Th2 cells in the lymph nodes and lungs after chronic HDM challenge. Treatment also reduced the secretion of IL-5 and IL-13 from co-cultured dendritic cells and T cells restimulated with HDM extract. Human epithelial cells cultured with Fbln1c peptide produced more CXCL1 mRNA than medium-treated controls. Our data show that Fbln1c may be a therapeutic target in chronic asthma. Copyright © 2017 Pathological Society of Great Britain and Ireland. Published by John Wiley & Sons, Ltd.

Oncogenomics of c-Myc transgenic mice reveal novel regulators of extracellular signaling, angiogenesis and invasion with clinical significance for human lung adenocarcinoma

The c-Myc transcription factor is frequently deregulated in cancers. To search for disease diagnostic and druggable targets a transgenic lung cancer disease model was investigated. Oncogenomics identified c-Myc target genes in lung tumors. These were validated by RT-PCR, Western Blotting, EMSA assays and ChIP-seq data retrieved from public sources. Gene reporter and ChIP assays verified functional importance of c-Myc binding sites. The clinical significance was established by RT-qPCR in tumor and matched healthy control tissues, by RNA-seq data retrieved from the TCGA Consortium and by immunohistochemistry recovered from the Human Protein Atlas repository. In transgenic lung tumors 25 novel candidate genes were identified. These code for growth factors, Wnt/β-catenin and inhibitors of death receptors signaling, adhesion and cytoskeleton dynamics, invasion and angiogenesis. For 10 proteins over-expression was confirmed by IHC thus demonstrating their druggability. Moreover, c-Myc over-expression caused complete gene silencing of 12 candidate genes, including Bmp6, Fbln1 and Ptprb to influence lung morphogenesis, invasiveness and cell signaling events. Conversely, among the 75 repressed genes TNFα and TGF-β pathways as well as negative regulators of IGF1 and MAPK signaling were affected. Additionally, anti-angiogenic, anti-invasive, adhesion and extracellular matrix remodeling and growth suppressive functions were repressed. For 15 candidate genes c-Myc-dependent DNA binding and transcriptional responses in human lung cancer samples were confirmed. Finally, Kaplan-Meier survival statistics revealed clinical significance for 59 out of 100 candidate genes, thus confirming their prognostic value. In conclusion, previously unknown c-Myc target genes in lung cancer were identified to enable the development of mechanism-based therapies.

Assessment of Hepatocellular Carcinoma Metastasis Glycobiomarkers Using Advanced Quantitative N-glycoproteome Analysis

Hepatocelluar carcinoma (HCC) is one of the most common malignant tumors with high incidence of metastasis. Glycosylation is involved in fundamental molecular and cell biology process occurring in cancer including metastasis formation. In this study, lectin microarray, lectin blotting, lectin affinity chromatography and tandem ¹⁸O stable isotope labeling coupled with liquid chromatography-mass spectrometer (LC-MS) analysis were applied to quantify the changes in N-glycosite occupancy for HCC metastasis serum. Firstly, lectin microarray was used to screen glycoforms and Phaseolus vulgaris Leucoagglutinin (PHA-L) reactive structure (β1,6-GlcNAc branched N-glycan) was found to be increased significantly in HCC patients with metastasis compared with those with non-metastasis. Then, PHA-L affinity glycoproteins were enriched followed by N-glycosite occupancy measurement with strategy of tandem ¹⁸O stable isotope labeling. 11 glycoproteins with significantly changed N-glycosite occupancy were identified, they were associated with cell migration, invasion and adhesion through p38 mitogen-activated protein kinase signaling pathway and nuclear factor kappa B signaling pathway. Quantification of N-glycosite occupancy for PHA-L reactive glycoproteins could help to discover important glycoproteins of potential clinically significance in terms of HCC etiology. Also, understanding of N-glycosite occupancy alterations will aid the characterization of molecular mechanism of HCC metastasis as well as establishment of novel glycobiomarkers.

Investigating the effect of fibulin-1 on the differentiation of human nasal inferior turbinate-derived mesenchymal stem cells into osteoblasts

Many extracellular matrix proteins have positive influences on the adhesion, proliferation, and differentiation of stem cells into specific cell linages. Fibulin-1 (FBLN1), a member of a growing family of extracellular glycoproteins, contributes to the structure of the extracellular matrix. Here, we investigated the effect of FBLN1 on the ability of human nasal inferior turbinate-derived mesenchymal stem cells (hTMSCs) to undergo osteogenic differentiation. After we generated recombinant FBLN1, the characteristics of FBLN1-treated hTMSCs were evaluated using MTT assay, ALP and mineralization activities, and quantitative real-time PCR. FBLN1 significantly enhanced the adhesion activity (p < 0.001) and proliferation of hTMSCs (p < 0.05). The ALP and mineralization activities of cells were dramatically increased (p < 0.01) after 9 and 12 days of FBLN1 treatment, respectively. This indicated the ability of FBLN1 to induce hTMSCs to differentiate into osteoblasts. Furthermore, increasing the mRNA levels of osteogenic marker genes, such as a transcriptional coactivator with a PDZ-binding motif (TAZ), alkaline phosphatase (ALP), collagen type I (Col I), and osteocalcin (OCN), improved bone repair and regeneration. © 2017 Wiley Periodicals, Inc. J Biomed Mater Res Part A: 105A: 2291-2298, 2017.

Fibulin-6 regulates pro-fibrotic TGF-β responses in neonatal mouse ventricular cardiac fibroblasts

Fibulin-6, an essential component of extracellular matrix determines the architecture of cellular junctions in tissues undergoing strain. Increased expression and deposition of fibulin-6 facilitates fibroblast migration in response to TGF-β, following myocardial infarction in mouse heart. The underlying mechanism still remains elusive. In conjunction with our previous study, we have now demonstrated that in fibulin-6 knockdown (KD) fibroblasts, not only TGF-β dependent migration, but also stress fiber formation, cellular networking and subsequently fibroblast wound contraction is almost abrogated. SMAD dependent TGF-β pathway shows ~75% decreased translocation of R-SMAD and co-SMAD into the nucleus upon fibulin-6 KD. Consequently, SMAD dependent pro-fibrotic gene expression is considerably down regulated to basal levels both in mRNA and protein. Also, investigating the non-SMAD pathways we observed a constitutive increase in pERK-levels in fibulin-6 KD fibroblast compared to control, but no change was seen in pAKT. Immunoprecipitation studies revealed 60% reduced interaction of TGF-β receptor II and I (TGFRII and I) accompanied by diminished phosphorylation of TGFRI at serin165 in fibulin-6 KD cells. In conclusion, fibulin-6 plays an important role in regulating TGF-β mediated responses, by modulating TGF-β receptor dimerization and activation to further trigger downstream pathways.

Fibulin-1 Binds to Fibroblast Growth Factor 8 with High Affinity: EFFECTS ON EMBRYO SURVIVAL

Fibulin-1 (FBLN1) is a member of a growing family of extracellular matrix glycoproteins that includes eight members and is involved in cellular functions such as adhesion, migration, and differentiation. FBLN1 has also been implicated in embryonic heart and valve development and in the formation of neural crest-derived structures, including aortic arch, thymus, and cranial nerves. Fibroblast growth factor 8 (FGF8) is a member of a large family of growth factors, and its functions include neural crest cell (NCC) maintenance, specifically NCC migration as well as patterning of structures formed from NCC such as outflow tract and cranial nerves. In this report, we sought to investigate whether FBLN1 and FGF8 have cooperative roles in vivo given their influence on the development of the same NCC-derived structures. Surface plasmon resonance binding data showed that FBLN1 binds tightly to FGF8 and prevents its enzymatic degradation by ADAM17. Moreover, overexpression of FBLN1 up-regulates FGF8 gene expression, and down-regulation of FBLN1 by siRNA inhibits FGF8 expression. The generation of a double mutant Fbln1 and Fgf8 mice (Fbln1(-/-) and Fgf8(-/-)) showed that haplo-insufficiency (Fbln1(+/-) and Fgf8(+/-)) resulted in increased embryonic mortality compared with single heterozygote crosses. The mortality of the FGF8/Fbln1 double heterozygote embryos occurred between 14.5 and 16.5 days post-coitus. In conclusion, FBLN1/FGF8 interaction plays a role in survival of vertebrate embryos, and reduced levels of both proteins resulted in added mortality in utero The FBLN1/FGF8 interaction may also be involved in the survival of neural crest cell population during development.

Fibulin-1 regulates the pathogenesis of tissue remodeling in respiratory diseases

Airway and/or lung remodeling, involving exaggerated extracellular matrix (ECM) protein deposition, is a critical feature common to pulmonary diseases including chronic obstructive pulmonary disease (COPD), asthma, and idiopathic pulmonary fibrosis (IPF). Fibulin-1 (Fbln1), an important ECM protein involved in matrix organization, may be involved in the pathogenesis of these diseases. We found that Fbln1 was increased in COPD patients and in cigarette smoke-induced (CS-induced) experimental COPD in mice. Genetic or therapeutic inhibition of Fbln1c protected against CS-induced airway fibrosis and emphysema-like alveolar enlargement. In experimental COPD, this occurred through disrupted collagen organization and interactions with fibronectin, periostin, and tenascin-c. Genetic inhibition of Fbln1c also reduced levels of pulmonary inflammatory cells and proinflammatory cytokines/chemokines (TNF-α, IL-33, and CXCL1) in experimental COPD. Fbln1c^-/- mice also had reduced airway remodeling in experimental chronic asthma and pulmonary fibrosis. Our data show that Fbln1c may be a therapeutic target in chronic respiratory diseases.

Fibulin-4 is a novel Wnt/β-Catenin pathway activator in human osteosarcoma

Fibulin-4, an extracellular glycoprotein implicated in connective tissue development and elastic fiber formation, draws increasing focuses in cancer research. However, little is known about the underlying oncogenic roles of Fibulin-4 in human osteosarcoma (OS). In this study, by immunohistochemical analysis, upregulated expression of Fibulin-4 was found in the OS clinical specimens and cell lines compared to their normal counterparts. Fibulin-4 was positively correlated with the T stage of OS patients, and the proliferation index Ki67. Based on informatics analysis and functional verification, microRNA-137 was identified as a potential upstream regulator of Fibulin-4. Knockdown of Fibulin-4 or introduction of microRNA-137 inhibited cell proliferation and promoted cell apoptosis, and adverse effects were observed by overexpression of Fibulin-4. Furthermore, the tumor-suppressive functions of microRNA-137 were markedly abolished by restoration of Fibulin-4 expression in OS cells. Mechanistically, Fibulin-4 activated Wnt/β-Catenin pathway and promoted the expression of its downstream targets, including CCND2, c-Myc and VEGF. Taken together, Fibulin-4 plays critical neoplastic roles in tumor growth of human OS by activating Wnt/β-Catenin signaling and may represent a potential therapeutic target.

Low expression of fibulin-1 correlates with unfavorable prognosis in gastric cancer

The tumor-suppressing role of fibulin-1 has been described in several types of cancers. However, the expression and role of fibulin-1 in the development and progression of gastric cancer (GC) remain largely unknown. In this study, RT-PCR and immunochemistry were used to detect the fibulin-1 expression in GC samples. We have found that the fibulin-1 protein and mRNA levels were downregulated in GC. When investigating the correlation between fibulin-1 expression and clinicopathological characteristics, we have found that low fibulin-1 protein expression was associated with poor tumor differentiation and advanced N stage. Low fibulin-1 protein expression was also an independent prognostic factor for patient survival. To clarify the reason of fibulin-1 downregulation in GC, the mRNA expression and methylation status of fibulin-1 were examined in GC fresh tissue samples (n = 36). We found that the transcriptional expression of fibulin-1 was negatively associated with fibulin-1 promoter hypermethylation, and fibulin-1 hypermethylation was associated with Helicobacter pylori infection. Finally, the effects of fibulin-1 overexpression on cell proliferation and apoptosis were examined. We have found that fibulin-1 overexpression suppressed the growth of GC both in vitro and in vivo and induced apoptosis by increasing cleaved caspase-3 expression. In conclusion, fibulin-1 acts as a tumor suppressor gene, is frequently hypermethylated in GC, and can potentially serve as a useful biomarker for patient prognosis.

Extracellular matrix-mediated cellular communication in the heart

The extracellular matrix (ECM) is a complex and dynamic scaffold that maintains tissue structure and dynamics. However, the view of the ECM as an inert architectural support has been increasingly challenged. The ECM is a vibrant meshwork, a crucial organizer of cellular microenvironments. It plays a direct role in cellular interactions regulating cell growth, survival, spreading, proliferation, differentiation and migration through the intricate relationship among cellular and acellular tissue components. This complex interrelationship preserves cardiac function during homeostasis; however it is also responsible for pathologic remodeling following myocardial injury. Therefore, enhancing our understanding of this cross-talk may provide mechanistic insights into the pathogenesis of heart failure and suggest new approaches to novel, targeted pharmacologic therapies. This review explores the implications of ECM-cell interactions in myocardial cell behavior and cardiac function at baseline and following myocardial injury.

Temporospatial expression of fibulin-1 after acute spinal cord injury in rats

OBJECTIVE

Fibulin-1 is a matricellular protein that plays important roles in motility inhibition in a variety of cells and blocks the proliferation of cultured neural stem cells. The biological function of fibulin-1 in the spinal cord has not been fully elucidated.

METHODS

To clarify the expressions and possible functions of fibulin-1 in spinal cord injury (SCI), we performed an acute spinal cord contusion injury model in adult rats. Our work studied the temporospatial expression patterns of fibulin-1.

RESULTS

Western blot analysis revealed that fibulin-1 levels significantly increased 5 days after spinal cord contusion. Immunohistochemistry confirmed an increased number of fibulin-1 immunopositive cells about 2 mm from the lesion site. Moreover, double immunofluorescence labeling suggested that these changes were especially prominent in neurons and microglia.

CONCLUSION

These findings suggest that fibulin-1 may be involved in neuronal apoptosis and microglial activation after SCI.

Calumenin and fibulin-1 on tumor metastasis: Implications for pharmacology

Tumor metastasis is a key cause of cancer mortality, and inhibiting migration of cancer cells is one of the major directions of anti-metastatic drug development. Calumenin and fibulin-1 are two extracellular proteins that synergistically inhibit cell migration and tumor metastasis, and could potentially be served as targets for pharmacological research of anti-metastatic drugs. This review briefly introduces the multi-function of these two proteins, and discusses the mechanism of how they regulate cell migration and tumor metastasis.

A novel intracellular fibulin-1D variant binds to the cytoplasmic domain of integrin beta 1 subunit

Fibulin-1 is a member of a growing family of proteins that includes eight members and is involved in cellular functions such as adhesion, migration and differentiation. Fibulin-1 has also been implicated in embryonic development of the heart and neural crest-derived structures. It is an integral part of the extracellular matrix (ECM) and has been shown to bind to a multitude of ECM proteins. However, fibulin-1 was first identified as a protein purified from placental extracts that binds to the cytoplasmic domain of integrin β1. Human fibulin-1 is alternatively spliced into four different isoforms namely A-D. These isoforms share a common N-terminus sequence that contains a secretion sequence but differ in their carboxy-terminal fibulin-1 module. In this report we identify a new splice variant of fibulin-1 that differs from all other fibulin-1 variants in the N-terminus sequence and has a similar carboxy-terminus sequence as fibulin-1D. This variant that we named fibulin-1D prime (fibulin-1D') lacks a secretion sequence and the anaphlatoxin region of fibulin-1 variants. The protein has an apparent molecular weight of 70.5kDa. Herein we show that fibulin-1D' binds to the intracellular domain of integrin β1 as well as to integrin α5β1. The protein was localized intracellularly in CHO cells transfected with a pEF4 plasmid containing full-length coding sequence of fibulin-1D'. We also localized the protein in human placenta. We propose that the fibulin-1D' variant might play a role in early embryo development as well as in modulating integrin β1 functions including adhesion and motility.

Fibulin-1 suppresses endothelial to mesenchymal transition in the proximal outflow tract

Endothelial to mesenchymal transition (EMT) that occurs during cardiac outflow tract (OFT) development is critical for formation of the semilunar valves. Fibulin-1 (Fbln1) is an extracellular matrix protein that is present at several sites of EMT, including the OFT (i.e., E9.5-10.5). The aim of this study was to determine the role of Fbln1 in EMT during the earliest events of OFT development. Examination of proximal OFT cushions in Fbln1 null embryos detected hypercellularity at both E9.5 (93% increase; p = 0.002) and E10.5 (43% increase; p = 0.01) as compared to wild type, suggesting that Fbln1 normally suppresses OFT endocardial cushion EMT. This was supported by studies of proximal OFT cushion explants, which showed that explants from Fbln1 null embryos displayed a 58% increase in cells migrating from the explants as compared to wild type (p = 0.005). We next evaluated the effects of Fbln1 deficiency on the expression of factors that regulate proximal OFT EMT. At E9.5, Fbln1 null proximal OFT endocardium and EMT-derived mesenchyme showed increased TGFβ2 (58% increase; p = 0.01) and increased Snail1-positive nuclei (27% increase; p = 0.0003). Histological examination of OFT cushions in Fbln1 null embryos (E9.5) also detected cells present in the cushion that were determined to be erythrocytes based on round morphology, autofluorescence, and positive staining for hemoglobin. Erythrocytes were also detected in Fbln1 null OFT cushions at E10.5. Together, the findings indicate that Fbln1 normally suppresses proximal OFT EMT preventing proximal cushion hypercellularity and blood cell accumulation.

Augmented expression of urokinase plasminogen activator and extracellular matrix proteins associates with multiple myeloma progression

Multiple myeloma (MM) represents a B cell malignancy, characterized by a monoclonal proliferation of malignant plasma cells. Interactions between tumor cells and extracellular matrix (ECM) are of importance for tumor invasion and metastasis. Protein levels of urokinase plasminogen activator (uPA) and fibulin 1, nidogen and laminin in plasma and serum respectively and mRNA levels of these molecules in peripheral blood mononuclear cells were determined in 80 subjects by using ELISA and quantitative PCR and data was analyzed with severity of disease. Pearson correlation was determined to observe interrelationship between different molecules. A statistical significant increase for ECM proteins (laminin, nidogen and fibulin 1) and uPA at circulatory level as well as at mRNA level was observed compared to healthy controls. The levels of these molecules in serum might be utilized as a marker of active disease. Significant positive correlation of all ECM proteins with uPA was found and data also correlates with severity of disease. Strong association found between ECM proteins and uPA in this study supports that there might be interplay between these molecules which can be targeted. This study on these molecules may help to gain insight into processes of growth, spread, and clinical behavior of MM.

Effects of oestrogen on long noncoding RNA expression in oestrogen receptor alpha-positive ovarian cancer cells

Although oestrogen (E2) signalling has long been implicated in epithelial ovarian cancer (EOC) progression, the underlying mechanisms remain unknown. Long noncoding RNAs (lncRNAs) play a major role in cancer progression; therefore, our aim was to explore whether any lncRNA is regulated by E2 and plays some potential roles in the hormonal regulation of EOC progression. Here, we reported that E2 significantly dysregulated 115 lncRNAs (fold change ≥1.5, P<0.05) in E2 receptor (ER) alpha (ERα)-positive EOC SKOV3 cells compared with E2-untreated controls based on the microarray analysis. E2 regulation of the expression of 58 lncRNAs was bioinformatics predicted to be ERα-mediated; this was confirmed for two candidates. Both TC0101441 and TC0101686 were dysregulated by E2 in another ERα-positive PEO1 cells but not in ERα-negative A2780 cells. Additionally, the modulation of TC0101441 and TC0101686 expression by E2 was abrogated by the ER inhibitor ICI 182, 780 and short hairpin RNAs targeting ERα (ERα-shRNA). Further study of the two lncRNA expression indicated that ERα-positive EOC tissues had lower expression of TC0101686 and higher expression of TC0101441 compared to ERα-negative tissues. Particularly, elevated TC0101441 expression was correlated with lymph node metastasis, showing a metastatic potential. Results of in vitro assays further confirmed the pro-metastatic effect of TC0101441 and revealed that knockdown of TC0101441 also impaired E2-induced EOC cell migration/invasion by at least partly, regulating MMP2 and MMP3. Together, our findings demonstrate, for the first time, that E2 modulates lncRNA expression in ERα-positive EOC cells and that this regulation is sometimes ERα-mediated. Furthermore, our findings reveal that TC0101441contributes to E2-induced EOC cell migration/invasion. These results may shed a new insight into estrogenic effect on EOC progression by providing a perspective of lncRNA.

Expression and clinical significance of estrogen-regulated long non-coding RNAs in estrogen receptor α-positive ovarian cancer progression

Estrogen (E2) has long been implicated in epithelial ovarian cancer (EOC) progression. The effects of E2 on cancer progression can be mediated by numerous target genes, including coding RNAs and, more recently, non-coding RNAs (ncRNAs). Among the ncRNAs, long ncRNAs (lncRNAs) have emerged as new regulators in cancer progression; therefore, our aim was to determine whether the expression of any lncRNAs is regulated by E2 and, if so, whether a subset of these lncRNAs have some clinical significance in EOC progression. A microarray was performed to identify E2-regulated lncRNAs in E2 receptor (ER) α-positive EOC cells. Bioinformatics analyses of lncRNAs were conducted, focusing on gene ontology and pathway analyses. Quantitative real-time polymerase chain reactions were performed to confirm the expression of certain lncRNAs in ERα-positive EOC tissues. The correlation between certain lncRNA expression and clinicopathological factors as well as prognosis in ERα-positive EOC patients was then analyzed. We showed that 115 lncRNAs exhibited significant changes in E2-treated SKOV3 cells compared with untreated controls. Most of these lncRNAs were predicated to have potential to contribute to cancer progression. Notably, three candidates (TC0100223, TC0101686 and TC0101441) were aberrantly expressed in ERα-positive compared to ERα-negative EOC tissues, showing correlations with some malignant cancer phenotypes such as advanced FIGO stage and/or high histological grade. Furthermore, multivariate analysis indicated that TC0101441 was an independent prognostic factor for overall survival. Taken together, these results indicate for the first time that E2 can modulate lncRNA expression in ERα-positive EOC cells and that certain lncRNAs are correlated with advanced cancer progression and suggestive of a prognostic indicator in ERα-positive EOC patients. Knowledge of these E2-regulated lncRNAs could aid in the future understanding of the estrogenic effect on EOC progression and may assist in the clinical design of new target therapies based on a perspective of lncRNA.

Genome-wide analysis of DNA methylation in tongue squamous cell carcinoma

Tongue squamous cell carcinoma (TSCC) is one of the most common types of oral cancer; however, its molecular mechanisms remain unclear. In this study, methylated DNA immunoprecipitation (MeDIP) coupled with methylation microarray analysis was performed to screen for aberrantly methylated genes in adjacent normal control and TSCC tissues from 9 patients. Roche NimbleGen Human DNA Methylation 385K Promoter Plus CpG Island Arrays were used to detect 28,226 CpG sites. A total of 1,269 hypermethylated CpG sites covering 330 genes and 1,385 hypomethylated CpG sites covering 321 genes were found in TSCC tissue, compared to the adjacent normal tissue. Furthermore, we chose three candidate genes (FBLN1, ITIH5 and RUNX3) and validated the DNA methylation status by methylation-specific PCR (MS-PCR) and the mRNA expression levels by reverse transcription PCR (RT-PCR). In TSCC tissue, FBLN1 and ITIH5 were shown to be hypermethylated and their expression was found to be decreased, and RUNX3 was shown to be hypomethylated, however, its mRNA expression was found to be increased. In addition, another three genes (BCL2L14, CDCP1 and DIRAS3) were tested by RT-PCR. In TSCC tissue, BCL2L14 and CDCP1 expressions were markedly upregulated, and DIRAS3 expression was significantly downregulated. Our data demonstrated that aberrant DNA methylation is observed in TSCC tissue and plays an important role in the tumorigenesis, development and progression of TSCC.