Tissue Factor Pathway Inhibitor-2 Is Upregulated by Vascular Endothelial Growth Factor and Suppresses Growth Factor-Induced Proliferation of Endothelial Cells

Curcumin inhibits the invasion and migration of pancreatic cancer cells by upregulating TFPI-2 to regulate ERK- and JNK-mediated epithelial-mesenchymal transition

PURPOSE

Pancreatic cancer (PC) is one of the most deadly human malignancies. Curcumin is a natural polyphenolic compound with wide-ranging pharmacological effects. Growing evidence suggests that curcumin has anticancer activity against PC, but the mechanism remains incompletely elucidated. This study aimed to investigate the effects and mechanisms of curcumin on the invasion and migration of PC cells.

METHODS

Effect of curcumin on tissue factor pathway inhibitor (TFPI)-2 mRNA expression in PC cells was initially identified using qRT-PCR. Cytotoxicity of curcumin was assessed with MTT assays and IC50 was calculated. Involvement of ERK and JNK pathways, as well as protein expression of TFPI-2 and epithelial-mesenchymal transition (EMT)-related markers, were detected using immunoblotting. Invasion and migration of PC cells were examined using Transwell assays. TFPI-2 expression was manipulated by transfection with siRNA and shRNA. Rescue assays were used to validate the effect of curcumin on cell invasion and migration via TFPI-2.

RESULTS

Curcumin increased the expression of TFPI-2 mRNA and protein in PC cells and attenuated cell invasion and migration. Curcumin also inhibited ERK and JNK pathways and EMT in PC cells. Knockdown of TFPI-2 partially reversed the inhibition of ERK and JNK pathways and EMT by curcumin. Mechanistically, curcumin upregulated TFPI-2, thereby inhibiting the ERK and JNK pathways, leading to the inhibition of EMT in PC cells.

CONCLUSION

Collectively, curcumin inhibits ERK- and JNK-mediated EMT through upregulating TFPI-2, which in turn suppresses the migration and invasion of PC cells. These findings provide new insights into the antitumor mechanism of curcumin.

FTO overexpression expedites wound healing and alleviates depression in burn rats through facilitating keratinocyte migration and angiogenesis via mediating TFPI-2 demethylation

Burn injury is a serious traumatic injury that leads to severe physical and psychosocial impairment. Wound healing after burn injury is a substantial challenge in medical community. This study investigated the biological effects of the demethylase fat mass and obesity-associated protein (FTO) on burn injury. FTO protein level in burn skin tissues of patients was measured with Western blot assay. Keratinocytes (HaCaT cells) were given heat stimulation to induce an in vitro burn injury model, and then transfected with overexpression plasmids of FTO (pcDNA-FTO) or small interfering RNA against FTO (si-FTO). Cell proliferation, migration, and angiogenesis in keratinocytes were evaluated with CCK-8, Transwell, and tube formation assays, respectively. Tissue factor pathway inhibitor-2 (TFPI-2) m6A methylation level was detected with MeRIP‑qPCR assay. Then rescue experiments were conducted to explore the effects of FTO/TFPI-2 axis on keratinocyte functions. Lentivirus carrying FTO overexpression plasmids was injected into a burn rat model to detect its effects on wound healing and depressive-like behaviors in burn rats. FTO was downregulated in burn skin and heat-stimulated keratinocytes. FTO prominently augmented proliferation, migration and angiogenesis in heat-stimulated keratinocytes, while FTO knockdown showed the opposite results. FTO inhibited TFPI-2 expression by FTO-mediated m6A methylation modification. TFPI-2 overexpression abrogated FTO mediated enhancement of proliferation, migration and angiogenesis in keratinocytes. Additionally, FTO overexpression accelerated wound healing and improved depressive-like behaviors in burn rat model. FTO prominently augmented proliferation, migration and angiogenesis in heat-stimulated keratinocytes though inhibiting TFPI-2, and then improved wound healing and depressive-like behaviors.

Tissue factor pathway inhibitor 2: Current understanding, challenges, and future perspectives

AIM

Tissue factor pathway inhibitor 2 (TFPI2) is a structural homolog of tissue factor pathway inhibitor 1 (TFPI1). Since TFPI2 is a placenta-derived protein, dynamic changes in TFPI2 levels may be related to pregnancy-related diseases. Furthermore, TFPI2 has been reported to be a novel serum biomarker for detecting ovarian cancer, especially clear cell carcinoma (CCC). This review aims to summarize the current knowledge on the biological function of TFPI2, highlight the major challenges that remain to be addressed, and discuss future research directions.

METHODS

Papers published up to March 31, 2023 in the PubMed and Google Scholar databases were included in this review. We also provide novel complementary information to what is known about the action of TFPI2.

RESULTS

Since TFPI2 concentrations in the blood of pregnant women, preeclampsia patients, and cancer patients vary greatly, its pathophysiological functions have attracted attention. Downregulation of TFPI2, a tumor-suppressor gene, by hypermethylation may contribute to the progression of several cancers. On the other hand, TFPI2 overexpressed in CCC is a risk factor for the development of thrombosis, possibly through inhibition of plasmin activity. However, agreement on the biological function of TFPI2 is still lacking and there are many scientific questions to be addressed. In particular, the lack of international standardization for the quantification of TFPI2 concentrations makes it difficult for researchers and clinicians to evaluate, pool, and compare data from different studies across countries.

DISCUSSION

This review summarizes current understandings and challenges in TFPI2 research and discusses future perspectives.

The Tissue Factor Pathway in Cancer: Overview and Role of Heparan Sulfate Proteoglycans

Historically, the only focus on tissue factor (TF) in clinical pathophysiology has been on its function as the initiation of the extrinsic coagulation cascade. This obsolete vessel-wall TF dogma is now being challenged by the findings that TF circulates throughout the body as a soluble form, a cell-associated protein, and a binding microparticle. Furthermore, it has been observed that TF is expressed by various cell types, including T-lymphocytes and platelets, and that certain pathological situations, such as chronic and acute inflammatory states, and cancer, may increase its expression and activity. Transmembrane G protein-coupled protease-activated receptors can be proteolytically cleaved by the TF:FVIIa complex that develops when TF binds to Factor VII (PARs). The TF:FVIIa complex can activate integrins, receptor tyrosine kinases (RTKs), and PARs in addition to PARs. Cancer cells use these signaling pathways to promote cell division, angiogenesis, metastasis, and the maintenance of cancer stem-like cells. Proteoglycans play a crucial role in the biochemical and mechanical properties of the cellular extracellular matrix, where they control cellular behavior via interacting with transmembrane receptors. For TFPI.fXa complexes, heparan sulfate proteoglycans (HSPGs) may serve as the primary receptor for uptake and degradation. The regulation of TF expression, TF signaling mechanisms, their pathogenic effects, and their therapeutic targeting in cancer are all covered in detail here.

Downregulation of growth plate genes involved with the onset of femoral head separation in young broilers

Femoral head separation (FHS) is characterized by the detachment of growth plate (GP) and articular cartilage, occurring in tibia and femur. However, the molecular mechanisms involved with this condition are not completely understood. Therefore, genes and biological processes (BP) involved with FHS were identified in 21-day-old broilers through RNA sequencing of the femoral GP. 13,487 genes were expressed in the chicken femoral head transcriptome of normal and FHS-affected broilers. From those, 34 were differentially expressed (DE; FDR ≤0.05) between groups, where all of them were downregulated in FHS-affected broilers. The main BP were enriched in receptor signaling pathways, ossification, bone mineralization and formation, skeletal morphogenesis, and vascularization. RNA-Seq datasets comparison of normal and FHS-affected broilers with 21, 35 and 42 days of age has shown three shared DE genes (FBN2, C1QTNF8, and XYLT1) in GP among ages. Twelve genes were exclusively DE at 21 days, where 10 have already been characterized (SHISA3, FNDC1, ANGPTL7, LEPR, ENSGALG00000049529, OXTR, ENSGALG00000045154, COL16A1, RASD2, BOC, GDF10, and THSD7B). Twelve SNPs were associated with FHS (p < 0.0001). Out of those, 5 were novel and 7 were existing variants located in 7 genes (RARS, TFPI2, TTI1, MAP4K3, LINK54, and AREL1). We have shown that genes related to chondrogenesis and bone differentiation were downregulated in the GP of FHS-affected young broilers. Therefore, these findings evince that candidate genes pointed out in our study are probably related to the onset of FHS in broilers.

MEG8 regulates Tissue Factor Pathway Inhibitor 2 (TFPI2) expression in the endothelium

A large portion of the genome is transcribed into non-coding RNA, which does not encode protein. Many long non-coding RNAs (lncRNAs) have been shown to be involved in important regulatory processes such as genomic imprinting and chromatin modification. The 14q32 locus contains many non-coding RNAs such as Maternally Expressed Gene 8 (MEG8). We observed an induction of this gene in ischemic heart disease. We investigated the role of MEG8 specifically in endothelial function as well as the underlying mechanism. We hypothesized that MEG8 plays an important role in cardiovascular disease via epigenetic regulation of gene expression. Experiments were performed in human umbilical vein endothelial cells (HUVECs). In vitro silencing of MEG8 resulted in impaired angiogenic sprouting. More specifically, total sprout length was reduced as was proliferation, while migration was unaffected. We performed RNA sequencing to assess changes in gene expression after loss of MEG8. The most profoundly regulated gene, Tissue Factor Pathway Inhibitor 2 (TFPI2), was fivefold increased following MEG8 silencing. TFPI2 has previously been described as an inhibitor of angiogenesis. Mechanistically, MEG8 silencing resulted in a reduction of the inhibitory histone modification H3K27me3 at the TFPI2 promoter. Interestingly, additional silencing of TFPI2 partially restored angiogenic sprouting capacity but did not affect proliferation of MEG8 silenced cells. In conclusion, silencing of MEG8 impairs endothelial function, suggesting a potential beneficial role in maintaining cell viability. Our study highlights the MEG8/TFPI2 axis as potential therapeutic approach to improve angiogenesis following ischemia.

Toward an understanding of tissue factor pathway inhibitor-2 as a novel serodiagnostic marker for clear cell carcinoma of the ovary

AIMS

Tissue factor pathway inhibitor (TFPI)-2 has recently emerged as a serodiagnostic marker for patients with epithelial ovarian cancer (EOC), especially clear cell carcinoma (CCC). This review discusses the biological properties of TFPI-2 and why serum levels are elevated in CCC patients.

METHODS

A comprehensive literature search was conducted in PubMed up until March, 2021.

RESULTS

TFPI-2 is a Kunitz-type protease inhibitor and negatively regulates the enzymatic activities, such as plasmin. TFPI-2 has been characterized as a tumor suppressor gene and was frequently downregulated through promoter hypermethylation in various human cancers. In contrast, TFPI-2 was overexpressed only in CCC. TFPI-2 may be involved in the pathophysiology of CCC, possibly through regulation of coagulation system, stabilization of extracellular matrix (ECM), and induction of intracellular signal transduction. TFPI-2 suppresses tissue factor-induced hypercoagulation in a hypoxic environment. TFPI-2, secreted by CCC cells, platelets, and adjacent vascular endothelial cells, may suppress tumor growth and invasion through ECM remodeling. Nuclear TFPI-2 may suppress matrix metalloproteinase production via transcription factors and modulate caspase-mediated cell apoptosis. CCC cells may upregulate the TFPI-2 expression to adapt to survival in the demanding environment. TFPI-2 is secreted by CCC cells and enters the systemic circulation, resulting in elevated blood levels.

DISCUSSION

Serum TFPI-2 reflects the overexpression of TFPI-2 in CCC tissues and is a potential serodiagnostic marker. Further research is needed to explore the expression, clinical significance, biological function, and potential mechanism of TFPI-2 in CCC.

Sex-Specific Transcriptome Differences in Human Adipose Mesenchymal Stem Cells

In humans, sexual dimorphism can manifest in many ways and it is widely studied in several knowledge fields. It is increasing the evidence that also cells differ according to sex, a correlation still little studied and poorly considered when cells are used in scientific research. Specifically, our interest is on the sex-related dimorphism on the human mesenchymal stem cells (hMSCs) transcriptome. A systematic meta-analysis of hMSC microarrays was performed by using the Transcriptome Mapper (TRAM) software. This bioinformatic tool was used to integrate and normalize datasets from multiple sources and allowed us to highlight chromosomal segments and genes differently expressed in hMSCs derived from adipose tissue (hADSCs) of male and female donors. Chromosomal segments and differentially expressed genes in male and female hADSCs resulted to be related to several processes as inflammation, adipogenic and neurogenic differentiation and cell communication. Obtained results lead us to hypothesize that the donor sex of hADSCs is a variable influencing a wide range of stem cell biologic processes. We believe that it should be considered in biologic research and stem cell therapy.

Interaction between tissue factor pathway inhibitor-2 gene polymorphisms and environmental factors associated with coronary atherosclerosis in a Chinese Han

To investigate the association of single nucleotide polymorphisms (SNPs) within tissue factor pathway inhibitor-2 (TFPI-2) gene polymorphisms and additional gene-environment interaction with coronary atherosclerosis risk. Generalized multifactor dimensionality reduction (GMDR) was used to screen the best interaction combination among 4 SNPs, smoking and alcohol drinking. Logistic regression was performed to investigate association between 4 SNPs within TFPI-2 gene and coronary atherosclerosis risk. Coronary atherosclerosis risk was significantly higher in carriers with the A allele of rs34489123 within TFPI-2 gene than those with GG genotype (GA+AA versus GG), adjusted OR (95% CI) = 1.70 (1.20-2.31), and was also higher in carriers with the G allele of rs4264 within TFPI-2 gene than those with AA genotype (AG+GG versus AA), adjusted OR (95% CI) = 1.62 (1.21-2.11). GMDR model shown the best models for gene-environment interaction were rs34489123 and smoking after adjusting the covariates, which scored 10 out of 10 for cross-validation consistency and 0.0010 for the sign test. Heavy LD was found for SNPs rs34489123 and rs59805398 (D' value was more than 0.8). Compared to control individuals, the AG haplotypes appeared to be significantly associated with increased coronary atherosclerosis risk, OR (95% CI) = 1.73 (1.22-2.32). We found that the A allele of rs34489123 and the G allele of rs4264 within TFPI-2 gene, interaction between rs34489123 and smoking and AG haplotypes were all associated with increased coronary atherosclerosis risk.

Proangiogenic Effect of Metformin in Endothelial Cells Is via Upregulation of VEGFR1/2 and Their Signaling under Hyperglycemia-Hypoxia

Cardiovascular disease is the leading cause of morbidity/mortality worldwide. Metformin is the first therapy offering cardioprotection in type 2 diabetes and non-diabetic animals with unknown mechanism. We have shown that metformin improves angiogenesis via affecting expression of growth factors/angiogenic inhibitors in CD34⁺ cells under hyperglycemia-hypoxia. Now we studied the direct effect of physiological dose of metformin on human umbilical vein endothelial cells (HUVEC) under conditions mimicking hypoxia-hyperglycemia. HUVEC migration and apoptosis were studied after induction with euglycemia or hyperglycemia and/or CoCl₂ induced hypoxia in the presence or absence of metformin. HUVEC mRNA was assayed by whole transcript microarrays. Genes were confirmed by qRT-PCR, proteins by western blot, ELISA or flow cytometry. Metformin promoted HUVEC migration and inhibited apoptosis via upregulation of vascular endothelial growth factor (VEGF) receptors (VEGFR1/R2), fatty acid binding protein 4 (FABP4), ERK/mitogen-activated protein kinase signaling, chemokine ligand 8, lymphocyte antigen 96, Rho kinase 1 (ROCK1), matrix metalloproteinase 16 (MMP16) and tissue factor inhibitor-2 under hyperglycemia-chemical hypoxia. Therefore, metformin’s dual effect in hyperglycemia-chemical hypoxia is mediated by direct effect on VEGFR1/R2 leading to activation of cell migration through MMP16 and ROCK1 upregulation, and inhibition of apoptosis by increase in phospho-ERK1/2 and FABP4, components of VEGF signaling cascades.

The potential inhibitory effects of miR‑19b on vulnerable plaque formation via the suppression of STAT3 transcriptional activity

Atherosclerotic plaque growth requires angiogenesis, and acute coronary syndrome (ACS) is usually triggered by the rupture of unstable atherosclerotic plaques. Previous studies have identified typically circulating microRNA (miRNA/miR) profiles in patients with ACS. miRNAs serve important roles in the pathophysiology of atherosclerotic plaque progression. The present study aimed to investigate the potential role and mechanism of miR‑19b in plaque stability. miRNA array data indicated that 28 miRNAs were differentially expressed in the plasma of patients with unstable angina (UA; n=12) compared with in control individuals (n=12), and miR‑19b exhibited the most marked upregulation. Circulating miR‑19b levels were further validated in another independent cohort, which consisted of 34 patients with UA and 24 controls, by quantitative polymerase chain reaction. Gene Ontology annotations of the predicted target genes of miR‑19b suggested that miR‑19b may be involved in endothelial cell (EC) proliferation, migration and angiogenesis, which was confirmed by Cell Counting kit‑8, wound healing and tube formation assays in the present study. Finally, the present study indicated that miR‑19b may suppress signal transducer and activator of transcription 3 (STAT3) tyrosine phosphorylation and transcriptional activity in ECs, as determined by western blot analysis and luciferase reporter assay. In conclusion, the present study revealed that increased miR‑19b expression may delay unstable plaque progression in patients with UA by inhibiting EC proliferation, migration and angiogenesis via the suppression of STAT3 transcriptional activity.

Involvement of the heparanase procoagulant domain in bleeding and wound healing

Essentials Heparanase forms a complex with tissue factor and enhances the generation of factor Xa. The present study was aimed to identify the procoagulant domain of heparanase. Procoagulant peptides significantly shortened bleeding time and enhanced wound healing. Tissue factor pathway inhibitor (TFPI)-2 derived peptides inhibited the procoagulant peptides.

SUMMARY

Background Heparanase, which is known to be involved in angiogenesis and metastasis, was shown to form a complex with tissue factor (TF) and to enhance the generation of activated factor X (FXa). Our study demonstrated that peptides derived from TF pathway inhibitor (TFPI)-2 impeded the procoagulant effect of heparanase, and attenuated inflammation, tumor growth, and vascularization. Aims To identify the procoagulant domain in the heparanase molecule, and to evaluate its effects in a model of wound healing that involves inflammation and angiogenesis. Methods Twenty-four potential peptides derived from heparanase were generated, and their effect was studied in an assay of FXa generation. Peptides 14 and 16, which showed the best procoagulant effect, were studied in a bleeding mouse model and in a wound-healing mouse model. Results Peptides 14 and 16 increased FXa levels by two-fold to three-fold, and, at high levels, caused consumption coagulopathy. The TFPI-2-derived peptides explored in our previous study were found to inhibit the procoagulant effect induced by peptides 14 and 16. In the bleeding model, time to clot formation was shortened by 50% when peptide 14 or peptide 16 was topically applied or injected subcutaneously. In the wound-healing model, the wound became more vascular, and its size was reduced to one-fifth as compared with controls, upon 1 week of exposure to peptide 14 or peptide 16 applied topically or injected subcutaneously. Conclusions The putative heparanase procoagulant domain was identified. Peptides derived from this domain significantly shortened bleeding time and enhanced wound healing.

Trypsinogen 4 boosts tumor endothelial cells migration through proteolysis of tissue factor pathway inhibitor-2

Proteases contribute to cancer in many ways, including tumor vascularization and metastasis, and their pharmacological inhibition is a potential anticancer strategy. We report that human endothelial cells (EC) express the trypsinogen 4 isoform of the serine protease 3 (PRSS3), and lack both PRSS2 and PRSS1. Trypsinogen 4 expression was upregulated by the combined action of VEGF-A, FGF-2 and EGF, angiogenic factors representative of the tumor microenvironment. Suppression of trypsinogen 4 expression by siRNA inhibited the angiogenic milieu-induced migration of EC from cancer specimens (tumor-EC), but did not affect EC from normal tissues. We identified tissue factor pathway inhibitor-2 (TFPI-2), a matrix associated inhibitor of cell motility, as the functional target of trypsinogen 4, which cleaved TFPI-2 and removed it from the matrix put down by tumor-EC. Silencing tumor-EC for trypsinogen 4 accumulated TFPI2 in the matrix. Showing that angiogenic factors stimulate trypsinogen 4 expression, which hydrolyses TFPI-2 favoring a pro-migratory situation, our study suggests a new pathway linking tumor microenvironment signals to endothelial cell migration, which is essential for angiogenesis and blood vessel remodeling. Abolishing trypsinogen 4 functions might be an exploitable strategy as anticancer, particularly anti-vascular, therapy.

Nrf2 in ischemic neurons promotes retinal vascular regeneration through regulation of semaphorin 6A

Delayed revascularization of ischemic neural tissue is a major impediment to preservation of function in central nervous system (CNS) diseases including stroke and ischemic retinopathies. Therapeutic strategies allowing rapid revascularization are greatly needed to reduce ischemia-induced cellular damage and suppress harmful pathologic neovascularization. However, key mechanisms governing vascular recovery in ischemic CNS, including regulatory molecules governing the transition from tissue injury to tissue repair, are largely unknown. NF-E2-related factor 2 (Nrf2) is a major stress-response transcription factor well known for its cell-intrinsic cytoprotective function. However, its role in cell-cell crosstalk is less appreciated. Here we report that Nrf2 is highly activated in ischemic retina and promotes revascularization by modulating neurons in their paracrine regulation of endothelial cells. Global Nrf2 deficiency strongly suppresses retinal revascularization and increases pathologic neovascularization in a mouse model of ischemic retinopathy. Conditional knockout studies demonstrate a major role for neuronal Nrf2 in vascular regrowth into avascular retina. Deletion of neuronal Nrf2 results in semaphorin 6A (Sema6A) induction in hypoxic/ischemic retinal ganglion cells in a hypoxia-inducible factor-1 alpha (HIF-1α)-dependent fashion. Sema6A expression increases in avascular inner retina and colocalizes with Nrf2 in human fetal eyes. Extracellular Sema6A leads to dose-dependent suppression of the migratory phenotype of endothelial cells through activation of Notch signaling. Lentiviral-mediated delivery of Sema6A small hairpin RNA (shRNA) abrogates the defective retinal revascularization in Nrf2-deficient mice. Importantly, pharmacologic Nrf2 activation promotes reparative angiogenesis and suppresses pathologic neovascularization. Our findings reveal a unique function of Nrf2 in reprogramming ischemic tissue toward neurovascular repair via Sema6A regulation, providing a potential therapeutic strategy for ischemic retinal and CNS diseases.

Tissue Factor Pathway Inhibitor-2 Gene Polymorphisms Associate With Coronary Atherosclerosis in Chinese Population

Tissue factor pathway inhibitor-2 (TFPI-2) may play critical roles in the pathogenesis of atherosclerosis. In this study, we aimed to investigate the association between TFPI-2 gene polymorphisms and coronary atherosclerosis.Four hundred and seven patients with coronary atherosclerosis and 306 individuals with normal coronary artery were enrolled in the present study. Nine single-nucleotide polymorphisms (SNPs) (rs3763473, rs59805398, rs60215632, rs59999573, rs59740167, rs34489123, rs4517, rs4264, and rs4271) were detected with polymerase chain reaction-direct sequencing method. Severity of coronary atherosclerosis was assessed by Gensini score. After the baseline investigation, patients with coronary atherosclerosis were followed up for incidence of cardiovascular events (CVEs).Eight SNPs were in accordance with the Hardy-Weinberg equilibrium, and 8 haplotypes were constructed based on rs59999573, rs59740167, and rs34489123 after linkage disequilibrium and haplotype analysis. Two SNPs (rs59805398 and rs34489123) and 5 haplotypes correlated with coronary atherosclerosis even after adjustment by Gensini score. At follow-up (median 53 months, range 1-60 months), 85 patients experienced CVE. However, there was no strong association between the gene polymorphisms and the occurrence of CVE.Tissue factor pathway inhibitor-2 gene polymorphisms were associated with coronary atherosclerosis in the Chinese population, suggesting that the information about TFPI-2 gene polymorphisms was useful for assessing the risk of developing coronary atherosclerosis, but there was not enough evidence showing it could predict occurrence of CVE.

Post-transcriptional control of Amblyomin-X on secretion of vascular endothelial growth factor and expression of adhesion molecules in endothelial cells

Angiogenesis is a pivotal process of homeostasis and tissue repair, but it also favours neovascularisation syndromes and cancer nutrition. The chemical mediation of angiogenesis is complex, involving a balance between serine proteases and their inhibitors. We addressed the mechanisms of action of a Kunitz serine protease inhibitor (KPI) on spontaneous angiogenesis, using Amblyomin-X, a KPI designed from the cDNA library of the Amblyomma cajennense tick. Amblyomin-X treatment (10-1000 ng/10 μL; each 48 h; 3 times) reduced the number of vessels in the subcutaneous dorsal tissue of male Swiss mice, as measured by intravital microscopy, haematoxylin-eosin staining, and PECAM-1 immunofluorescence labeling. Incubation of Amblyomin-X with t-End endothelial cells, a murine endothelial microvascular lineage, did not alter cell proliferation, cell-cycle phases, necrosis and apoptosis, and the production of nitric oxide and prostaglandin E2. Nevertheless, Amblyomin-X treatment reduced t-End migration and adhesion to Matrigel(®), and inhibited the VEGF-A secretion and VCAM-1 and β3 integrin expressions by posttranscriptional pathways. Together, data herein outline novel posttranscriptional mechanisms of KPIs on endothelial cells during angiogenesis and point out the possible application of Amblyomin-X as a local inhibitor to undesired neovascularisation process.

Promoter hypermethylation and silencing of tissue factor pathway inhibitor-2 in oral squamous cell carcinoma

Background

The treatment of oral squamous cell carcinoma (OSCC) following early detection is associated with good outcomes. Therefore, the survival and prognosis of OSCC patients could be hugely improved by identifying reliable biomarkers for the early diagnosis of the disease. Our previous methylation microarray analysis results have suggested that the gene encoding tissue factor pathway inhibitor-2 (TFPI-2) is a potential clinical predictor as well as a key regulator involved in OSCC malignancy.

Methods

Methylation of the TFPI-2 promoter in oral tissue specimens was evaluated by bisulfite sequencing assay, quantitative methylation-specific PCR, and pyrosequencing assay. The differences in methylation levels among the groups were compared using the Mann–Whitney U test. The area under the receiver operating characteristic curve (AUROC) was used to evaluate the discrimination ability for detecting OSCC. Cellular TFPI-2 expression was analyzed by quantitative reverse-transcription PCR before and after treatment with 5′-aza-2′-deoxycytidine and trichostatin A, to confirm whether TFPI-2 was epigenetically silenced in OSCC cells. We investigated whether TFPI-2 plays a role as a tumor suppressor by establishing TFPI-2-overexpressing OSCC cells and subjecting them to in vitro cellular proliferation, migration, and invasion assays, as well as an in vivo metastasis assay.

Results

TFPI-2 was hypermethylated in OSCC tissues versus normal oral tissues (P < 0.0001), with AUROC = 0.91, when using a pyrosequencing assay to quantify the methylation level. TFPI-2 silencing in OSCC was regulated by both DNA methylation and chromatin histone modification. Restoration of TFPI-2 counteracted the invasiveness of OSCC by inhibiting the enzymatic activity of matrix metalloproteinase-2, and consequently interfered with OSCC metastasis in vivo.

Conclusions

Our data suggest strongly that TFPI-2 is a down-regulated tumor suppressor gene in OSCC, probably involving epigenetic silencing mechanisms. The loss of TFPI-2 expression is a key event for oral tumorigenesis, especially in the process of tumor metastasis.

High-level production of active human TFPI-2 Kunitz domain in plant

Plants are an attractive production system alternative to cell bioreactor not only because of its lower production costs, but also due to its lack of mammalian pathogens and contaminants, plant capacity to generate appropriate eukaryotic folding and in many cases correct post-translational modifications. In recent years, several recombinant proteins and antibodies have been introduced in the biopharmaceutical market, in particular in cancer therapeutics. Kunitz domain 1 (KD1), a domain of Human Tissue Factor Pathway Inhibitor-2 (TFPI-2), has an outstanding potential in cancer treatment because it is a potent inhibitor of extracellular serine proteinases involved in tumor progression and angiogenesis. We present here the expression and purification of active human KD1 in different Nicotiana species as hosts and its stability during the infection process using a construct derived from a Tobacco mosaic virus (TMV) vector. Our purification protocol allows to recover over 100mg of active human KD1 per batch of 1 kg of plant tissue at about 97% purity. The yields are reproducible, being N. benthamiana the best system where higher levels of KD1 are obtained. Recombinant KD1 was also used to produce a high-sensitivity polyclonal antibody able to detect not only KD1 but also full-length TFPI-2. Finally, we show that this platform is a valuable alternative for the large scale production of KD1.

Low expression of TFPI-2 associated with poor survival outcome in patients with breast cancer

Background

The purpose of this study is to evaluate the prognostic value of TFPI-2 expression in breast cancer patients through examining the correlation between TFPI-2 expression and breast cancer clinicopathologic features.

Methods

Immunohistochemical staining combined with digital image analysis was used to quantify the expression of TFPI-2 protein in breast tumor tissues. For evaluation of the prognostic value of TFPI-2 expression to each clinicopathologic factor, Kaplan-Meier method and COX’s Proportional Hazard Model were employed.

Results

TFPI-2 expression was significantly correlated with tumor size, lymph node metastasis, histologic grade, clinical stage, and vessel invasion. More importantly, TFPI-2 expression was also associated with disease-free survival (DFS) of breast cancer patients. We found that patients with high TFPI-2 expression had longer DFS compared with those with low or negative expression of TFPI-2 (P <0.05, log-rank test). Cox’s regression analysis indicated that TFPI-2 expression, histologic grade, and vessel invasion might be significant prognostic factors for DFS, while TFPI-2 expression and histologic grade were the most significant independent predictors for tumor recurrence. Compared with the group with low/high TFPI-2 expression, the TFPI-2 negative group was more likely to have tumor relapse. The hazard ratio of DFS is 0.316 (P <0.01).

Conclusions

Low or negative expression of TFPI-2 is associated with breast cancer progression, recurrence and poor survival outcome after breast cancer surgery. TFPI-2 expression in breast tumors is a potential prognostic tool for breast cancer patients.

MEF2C ablation in endothelial cells reduces retinal vessel loss and suppresses pathologic retinal neovascularization in oxygen-induced retinopathy

Ischemic retinopathies, including retinopathy of prematurity and diabetic retinopathy, are major causes of blindness. Both have two phases, vessel loss and consequent hypoxia-driven pathologic retinal neovascularization, yet relatively little is known about the transcription factors regulating these processes. Myocyte enhancer factor 2 (MEF2) C, a member of the MEF2 family of transcription factors that plays an important role in multiple developmental programs, including the cardiovascular system, seems to have a significant functional role in the vasculature. We, therefore, generated endothelial cell (EC)-specific MEF2C-deficient mice and explored the role of MEF2C in retinal vascularization during normal development and in a mouse model of oxygen-induced retinopathy. Ablation of MEF2C did not cause appreciable defects in normal retinal vascular development. However, MEF2C ablation in ECs suppressed vessel loss in oxygen-induced retinopathy and strongly promoted vascular regrowth, consequently reducing retinal avascularity. This finding was associated with suppression of pathologic retinal angiogenesis and blood-retinal barrier dysfunction. MEF2C knockdown in cultured retinal ECs using small-interfering RNAs rescued ECs from death and stimulated tube formation under stress conditions, confirming the endothelial-autonomous and antiangiogenic roles of MEF2C. HO-1 was induced by MEF2C knockdown in vitro and may play a role in the proangiogenic effect of MEF2C knockdown on retinal EC tube formation. Thus, MEF2C may play an antiangiogenic role in retinal ECs under stress conditions, and modulation of MEF2C may prevent pathologic retinal neovascularization.

Reduced expression of tissue factor pathway inhibitor-2 contributes to apoptosis and angiogenesis in cervical cancer

Background

Tissue factor pathway inhibitor-2 (TFPI-2) is an extracellular matrix associated broad-spectrum Kunitz-type serine proteinase inhibitor. Recently, down regulation of TFPI-2 was suggested to be involved in tumor invasion and metastasis in some cancers.

Methods

This study involved 12 normal cervical squamous epithelia, 48 cervical intraepithelial neoplasia (CIN), and 68 cervical cancer. The expression of TFPI-2, Ki-67 and vascular endothelial growth factor (VEGF) were investigated by immunohistochemistry staining. The apoptolic index(AI) was determined with an in situ end-labeling assay(TUNEL). And the marker of CD34 staining was used as an indicator of microvessel density (MVD).

Results

TFPI-2 expression has a decreasing trend with the progression of cervical cancer and was significantly correlated with FIGO stage, lymph node metastasis and HPV infection. In addition, there were significant positive correlations between the grading of TFPI-2 expression and AI(P = 0.004). In contrast, the expression of TFPI-2 and VEGF or MVD was negatively correlated (both p < 0.001). However, we did not establish any significant correlation between Ki-67 and TFPI-2 expression in cervical cancer.

Conclusions

The results suggested that the expression of TFPI-2 had a decreasing trend with tumor progression of cervical cancer. There was a close association between the expression of TFPI-2 and tumor cell apoptosis and angiogenesis in patients with cervical cancer. TFPI-2 may play an inhibitive role during the development of cervical cancer.

Inhibition of pathological retinal angiogenesis by the integrin αvβ3 antagonist tetraiodothyroacetic acid (tetrac)

Retinal angiogenesis is a major cause of blindness in ischemic retinopathies including diabetic retinopathy and retinopathy of prematurity. Integrin αvβ3 is a promising therapeutic target for ocular angiogenesis, modulating the pro-angiogenic actions of multiple growth factors. In this study, we sought to determine the effects of the integrin αvβ3 antagonist tetra-iodothyroacetic acid (tetrac) on the angiogenic actions of VEGF and erythropoietin (EPO) in cultured human retinal endothelial cells. In addition, we investigated the effect of tetrac and a nanoparticulate formulation of tetrac on retinal angiogenesis in vivo, in the mouse oxygen-induced retinopathy (OIR) model. Tetrac inhibitory activity was evaluated in human retinal endothelial cells treated with VEGF and/or EPO. Endothelial cell proliferation, migration, and tube formation were assessed, in addition to phosphorylation of ERK1/2. For the studies of the oxygen-induced retinopathy model, C57BL/6 mice were exposed to 75% oxygen from postnatal day (P)7 to P12, and then returned to room air. Tetrac and tetrac-nanoparticle (tetrac-NP) were administered at P12 and P15 by either intraperitoneal or intravitreal injection. Retinal neovascularization was quantitated at P18. Tetrac significantly inhibited pro-angiogenic effects of VEGF and/or EPO on retinal endothelial cells, indicating that the angiogenic effects of both growth factors are dependent on integrin αvβ3. Retinal neovascularization in the OIR model was significantly inhibited by both tetrac and tetrac-NP. These results indicate that the integrin αvβ3 antagonist, tetrac, is an effective inhibitor of retinal angiogenesis. The ability of tetrac to inhibit the pro-angiogenic effect of both VEGF and EPO on retinal endothelial cells suggests that tetrac (and antagonism of integrin αvβ3) is a viable therapeutic strategy for proliferative diabetic retinopathy.

Tissue factor pathway inhibitor 2 is induced by thrombin in human macrophages

Tissue factor pathway inhibitor 2 (TFPI2) is a serine protease inhibitor critical for the regulation of extracellular matrix remodeling and atherosclerotic plaque stability. Previously, we demonstrated that TFPI2 expression is increased in monocytes from patients with familial combined hyperlipidemia (FCH). To gain insight into the molecular mechanisms responsible for this upregulation, we examined TFPI2 expression in THP-1 macrophages exposed to lipoproteins and thrombin. Our results showed that TFPI2 expression was not affected by treatment with very low density lipoproteins (VLDL), but was induced by thrombin (10 U/ml) in THP-1 (1.9-fold increase, p<0.001) and human monocyte-derived macrophages (2.3-fold increase, p<0.005). The specificity of the inductive effect was demonstrated by preincubation with the thrombin inhibitors hirudin and PPACK, which ablated thrombin effects. TFPI2 induction was prevented by pre-incubation with MEK1/2 and JNK inhibitors, but not by the EGF receptor antagonist AG1478. In the presence of parthenolide, an inhibitor of NFκB, but not of SR-11302, a selective AP-1 inhibitor, thrombin-mediated TFPI2 induction was blunted. Our results also show that thrombin treatment increased ERK1/2, JNK and IκBα phosphorylation. Finally, we ruled out the possibility that TFPI2 induction by thrombin was mediated by COX-2, as preincubation with a selective COX-2 inhibitor did not prevent the inductive effect. In conclusion, thrombin induces TFPI2 expression by a mechanism involving ERK1/2 and JNK phosphorylation, leading finally to NFkB activation. In the context of atherosclerosis, thrombin-induced macrophage TFPI2 expression could represent a means of avoiding excessive activation of matrix metalloproteases at sites of inflammation.

Tissue factor pathway inhibitor-2 is downregulated by ox-LDL and inhibits ox-LDL induced vascular smooth muscle cells proliferation and migration

INTRODUCTION

Tissue factor pathway inhibitor-2 (TFPI-2) is a member of the Kunitz-type family of serine protease inhibitors, which inhibits several matrix metalloproteinases activity involved in extracellular matrix degradation. Studies have shown low TFPI-2 expression in the shoulder regions of atherosclerotic plaques. But studies evaluating its role in the progression of atherosclerotic plaque are scarce. Vascular smooth muscle cells (VSMCs) are important components of atherosclerotic plaques and oxidized low density lipoprotein (ox-LDL) is an important detrimental factor of atherosclerosis. The aim of this study is to elucidate the effect of TFPI-2 on smooth muscle cell proliferation and migration induced by ox-LDL.

METHODS

Retroviruses expressing human TFPI-2 were constructed. Cell proliferation was determined by CCK-8 assay. Cell apoptosis was analyzed by double staining of FITC-Annexin V and propidium iodide. Cell migration was studied through a Transwell chamber and with a scratch-wound assay. The matrix metalloproteinase-2 and -9 activities were analyzed by gelatin zymography. Phosphorylation of FAK was analyzed by western blot.

RESULTS

TFPI-2 over-expression of mRNA and protein was confirmed in infected cells. CCK-8 assay showed that TFPI-2 inhibit VSMCs proliferation induced by ox-LDL while without cytotoxicity to VSMCs. Transwell and scratch wound assay confirmed TFPI-2 over-expression can inhibit VSMC migration. Zymography assay showed that TFPI-2 can inhibit MMP-2, 9 activity induced by ox-LDL. Western blot assay showed TFPI-2 can inhibit cyclinD1 expression and FAK phosphorylation.

CONCLUSION

TFPI-2 over-expression may strongly inhibit the proliferation and migration of VSMCs and suppresses MMP-2, 9 activity induced by ox-LDL, making it a promising candidate for treatment of atherosclerotic process.

Recombinant TFPI-2 enhances macrophage apoptosis through upregulation of Fas/FasL

Tissue factor pathway inhibitor-2 (TFPI-2) is a Kunitz-type serine proteinase inhibitor with inhibitory activity toward activated factor XI, plasma kallikrein, plasmin, certain matrix metalloproteinases, and the tissue factor-activated factor VII complex. In addition, TFPI-2 has other functions such as promoting cell migration and inducing apoptosis. In the present study, we investigated if TFPI-2 induced apoptosis in cultured U937-derived macrophages and the possible signal pathways that involved in the apoptotic process. Apoptotic DNA fragment detection and caspase-3,9 activity measurements indicated that rTFPI-2 promoted U937-derived macrophage apoptosis. Hoechst 33342 assay and flow cytometry further showed that rTFPI-2 induced apoptosis in cultured macrophages in a dose-dependent manner. Because death receptors of the TNF family such as Fas are the best-understood death pathways that recruit Fas-associated death domain (FADD) and procaspase-8 to the receptor in macrophages, we investigated the expression of Fas and its ligand (FasL) and downstream signal caspase-8 by Western blot analysis. The results indicated that the process of apoptosis triggered by rTFPI-2 was, at least in part, actively conducted by U937-derived macrophages possibly through Fas/FasL signal pathway. In brief, rTFPI-2 may have the potential usefulness in inducing macrophages apoptosis, which suggest TFPI-2 might have antiatherogenic effects.

Activation of human liver sinusoidal endothelial cell by human platelets induces hepatocyte proliferation

BACKGROUND & AIMS

We previously reported that platelets promote hepatocyte proliferation. In this study, we focused on the role of platelets in liver sinusoidal endothelial cells (LSECs) in addition to their role in hepatocyte in liver regeneration.

METHODS

Immortalized human LSECs (TMNK-1) were used. The LSECs were co-cultured with human platelets, and the proliferation of LSECs and the excretion of growth factors and interleukin-6 (IL-6) were subsequently measured. The main factor from platelets which induced the excretion of IL-6 from LSECs was determined using inhibitors of each component contained in the platelets. The need for direct contact between platelets and LSECs was investigated using cell culture inserts. The proliferation of human primary hepatocytes was measured after the addition of the supernatant of LSECs cultured with or without platelets.

RESULTS

The number of LSECs cocultured with platelets significantly increased. Excretion of IL-6 and vascular endothelial growth factor (VEGF) increased in LSECs with platelets. JTE-013, a specific antagonist for sphingosine 1-phosphate (S1P) 2 receptors, inhibited the excretion of IL-6 from LSECs after the addition of platelets. When the platelets and LSECs were separated by the cell culture insert, the excretion of IL-6 from LSECs was decreased. DNA synthesis was significantly increased in human primary hepatocytes cultured with the supernatant of LSECs with platelets.

CONCLUSIONS

Platelets promote LSEC proliferation and induce IL-6 and VEGF production. Direct contact between the platelets and LSECs and S1P, that are contained in platelets, were involved in the excretion of IL-6 from LSECs. IL-6 from LSECs induced proliferation of parenchymal hepatocytes.

Tissue factor pathway inhibitor-2 is induced by fluid shear stress in vascular smooth muscle cells and affects cell proliferation and survival

OBJECTIVE

Vascular smooth muscle cells (SMCs) are exposed to fluid shear stress (FSS) after interventional procedures such as balloon-angioplasty. Whereas the effects of hemodynamic forces on endothelial cells are explored in detail, the influence of FSS on smooth muscle cell function is poorly characterized. Here, we investigated the effect of FSS on SMC gene expression and function.

METHODS

Laminar FSS of arterial level (14 dynes/cm(2)) was applied to SMC cultures for 24 hours in a parallel-plate flow chamber. The effect of FSS on gene expression was first screened with microarray technology, and results further verified by real time polymerase chain reaction (RT-PCR) and immunoblotting. Tissue factor pathway inhibitor-2 (TFPI-2) and caspase-3 protein expression was studied in the rat carotid artery after balloon-injury, and the effect of TFPI-2 on SMC DNA synthesis and apoptosis was examined in vitro.

RESULTS

Microarrays identified TFPI-2 as one of the most differentially expressed gene by FSS in cultured SMCs (P < .001). Gene set enrichment analysis revealed significant regulation of genes linked to proliferation, apoptosis, and cell cycle regulation. TFPI-2 induction was confirmed by RT-PCR and immunoblotting demonstrating a more than 400-fold (P < .001) increase in TFPI-2 mRNA in SMCs exposed to FSS compared with static controls, and a consistent protein upregulation. Functionally, SMC proliferation was decreased by FSS (P < .001), and recombinant TFPI-2 was found to inhibit SMC proliferation (P < .001) and induce SMC apoptosis as indicated by activation of caspase-3 (P < .01). In vivo, TFPI-2 expression was found to be upregulated 5, 10, and 20 hours (P < .01) after rat carotid balloon injury, and immunohistochemistry demonstrated TFPI-2 protein in FSS-exposed luminal SMCs, co-localized with caspase-3 in the rat carotid neointima.

CONCLUSION

FSS influenced gene expression associated with cell growth and apoptosis in cultured SMCs and strongly induced expression of TFPI-2 mRNA and protein. TFPI-2 was expressed in luminal, FSS-exposed SMCs together with caspase-3 in the rat carotid neointima after balloon injury. Functionally, TFPI-2 may play a role in vessel wall repair by regulating SMC proliferation and survival. Further studies are needed to elucidate the mechanisms by which TFPI-2 controls SMC function.

Delivery of TFPI-2 using SonoVue and adenovirus results in the suppression of thrombosis and arterial re-stenosis

Genes could be used to treat atherosclerosis. The key problem is how to target a gene through the walls of arteries in free-flowing blood. TFPI-2 has been shown to suppress thrombosis and arterial re-stenosis, which indicates its potential function in gene therapy for atherosclerosis. The microbubble ultrasound contrast agent is widely applied in diagnostic imaging, and could be used for transferring genes into arteries. By transfecting TFPI-2 into arteries using SonoVue (a kind of microbubble ultrasound contrast agent), we identified TFPI-2 as an available factor for inhibiting the proliferation of vascular endothelial cells in vivo. Compared with adenovirus, SonoVue showed similar gene transfection efficiency, but the latter showed stronger inhibition of thrombosis and arterial re-stenosis with a high expression of TFPI-2 protein in vitro and in vivo. SonoVue was less damaging when transfecting genes into the arterial wall. These data indicate that transfecting human TFPI-2 into the arterial wall may suppress thrombosis and arterial re-stenosis, and reduce atherosclerosis.

Molecular regulation of vasculogenic mimicry in tumors and potential tumor-target therapy

“Vasculogenic mimicry (VM)”, is a term that describes the unique ability of highly aggressive tumor cells to express a multipotent, stem cell-like phenotype, and form a pattern of vasculogenic-like networks in three-dimensional culture. As an angiogenesis-independent pathway, VM and/or periodic acid-schiff-positive patterns are associated with poor prognosis in tumor patients. Moreover, VM is resistant to angiogenesis inhibitors. Here, we will review the advances in research on biochemical and molecular signaling pathways of VM in tumors and on potential anti-VM therapy strategy.

Vascular endothelial growth factor induces MEF2C and MEF2-dependent activity in endothelial cells

PURPOSE

Vascular endothelial growth factor is a key regulator of physiological and pathologic angiogenesis. Although much is known about the major upstream signaling pathways of VEGF in endothelial cells, less is known about key transcription factors involved in VEGF action. The transcription factor myocyte enhancer factor (MEF)-2C is thought to play an important role in vasculogenesis and angiogenesis during vascular development. The purpose of this study was to investigate the regulation of MEF2C expression and MEF2-dependent activity in endothelial cells by VEGF.

METHODS

Expression of MEF2C in human retinal endothelial cells and human umbilical vein endothelial cells was assayed by real-time PCR and Western blot. VEGF regulation of MEF2-dependent transcription was studied using an MEF2-luciferase reporter construct containing three copies of a high-affinity MEF2 binding site. The effect of MEF2 on endothelial cell migration was evaluated using a dominant-negative MEF2C mutant.

RESULTS

VEGF induced MEF2C expression in a dose- and time-dependent fashion. This induction was completely abrogated by the inhibition of protein kinase C and was partially blocked by the inhibition of PKC-beta and PKC-delta. In addition to regulating MEF2C expression, VEGF stimulated transcription from an MEF2-dependent promoter. VEGF stimulation of transcription was significantly reduced by the inhibition of calcineurin, CaMKII, p38 MAPK, and PKC, but not by the inhibition of ERK1/2 or BMK1/ERK5. Transfection of a dominant-negative mutant of MEF2C significantly inhibited VEGF-stimulated endothelial cell migration.

CONCLUSIONS

These results implicate VEGF as a key regulator of MEF2C and suggest that MEF2 may be an important mediator of VEGF in endothelial cells.

Tissue factor pathway inhibitor-2 was repressed by CpG hypermethylation through inhibition of KLF6 binding in highly invasive breast cancer cells

Background

Tissue factor pathway inhibitor-2 (TFPI-2) is a matrix-associated Kunitz inhibitor that inhibits plasmin and trypsin-mediated activation of zymogen matrix metalloproteinases involved in tumor progression, invasion and metastasis. Here, we have investigated the mechanism of DNA methylation on the repression of TFPI-2 in breast cancer cell lines.

Results

We found that both protein and mRNA of TFPI-2 could not be detected in highly invasive breast cancer cell line MDA-MB-435. To further investigate the mechanism of TFPI-2 repression in breast cancer cells, 1.5 Kb TFPI-2 promoter was cloned, and several genetic variations were detected, but the promoter luciferase activities were not affected by the point mutation in the promoter region and the phenomena was further supported by deleted mutation. Scan mutation and informatics analysis identified a potential KLF6 binding site in TFPI-2 promoter. It was revealed, by bisulfite modified sequence, that the CpG island in TFPI-2 promoter region was hypermethylated in MDA-MB-435. Finally, using EMSA and ChIP assay, we demonstrated that the CpG methylation in the binding site of KLF-6 diminished the binding of KLF6 to TFPI-2 promoter.

Conclusion

In this study, we found that the CpG islands in TFPI-2 promoter was hypermethylated in highly invasive breast cancer cell line, and DNA methylation in the entire promoter region caused TFPI-2 repression by inducing inactive chromatin structure and decreasing KLF6 binding to its DNA binding sequence.

Microarray analysis reveals differences in expression of cell surface and extracellular matrix components during development of the trout ovary and testis

Trout normally spawn at 3 years of age, however, a small percentage mature a year early. This provides an opportunity to study reproductive timing and developmental processes. The ovarian and testicular extracellular matrix (ECM) participates in processes such as growth, adhesion, differentiation, cell migration and patterning. The composition of the ECM defines the interactions of specific regulatory ligands with their receptors and modulates and regulates gonadal function. To identify some of the genes involved in these processes, a 16,006-gene salmonid cDNA microarray was used to compare three-year-old normal with two-year-old normal (maturing) and with two-year-old precocious (pre-spawn) ovarian and testicular transcriptomes. We provide evidence for differences in expression of some of the genes during vasculogenesis, angiogenesis, fibrillogenesis and other processes involving ECM remodeling. Sex-specific gene expression differences of ECM components were documented between the trout ovary and testis in each developmental state. Significant differences in the expression of genes involved in translation, transcription, cell-cycling and differentiation were identified. We also report, for the first time, unequivocal evidence for the transcription of high levels of adult and embryonic hemoglobins in the developed ovary; and for the expression of transcripts that encode zona pellucida glycoproteins in both the ovary and testis of trout.