Differential functions of genes regulated by VEGF-NFATc1 signaling pathway in the migration of pulmonary valve endothelial cells

RCAN1 in cardiovascular diseases: molecular mechanisms and a potential therapeutic target

Cardiovascular diseases (CVDs) are the leading cause of mortality worldwide. Considerable efforts are needed to elucidate the underlying mechanisms for the prevention and treatment of CVDs. Regulator of calcineurin 1 (RCAN1) is involved in both development/maintenance of the cardiovascular system and the pathogenesis of CVDs. RCAN1 reduction protects against atherosclerosis by reducing the uptake of oxidized low-density lipoproteins, whereas RCAN1 has a protective effect on myocardial ischemia/reperfusion injury, myocardial hypertrophy and intramural hematoma/aortic rupture mainly mediated by maintaining mitochondrial function and inhibiting calcineurin and Rho kinase activity, respectively. In this review, the regulation and the function of RCAN1 are summarized. Moreover, the dysregulation of RCAN1 in CVDs is reviewed. In addition, the beneficial role of RCAN1 reduction in atherosclerosis and the protective role of RCAN1 in myocardial ischemia/reperfusion injury, myocardial hypertrophy and intramural hematoma /aortic rupture are discussed, as well as underlying mechanisms. Furthermore, the therapeutic potential and challenges of targeting RCAN1 for CVDs treatment are also discussed.

Acute cytotoxicity and increased vascular endothelial growth factor after in vitro nitrogen mustard vapor exposure

Nitrogen mustard (NM) is a highly toxic alkylating agent. Inhalation exposure can cause acute and chronic lung injury. This study's aims were to develop an in vitro coculture model of mustard-induced airway injury and to identify growth factors contributing to airway pathology. Primary human bronchial epithelial cells cultured with pulmonary endothelial cells were exposed to NM (25, 50, 100, 250, or 500 μM) or PBS (control) for 1 hour. Lactate dehydrogenase (LDH) and transepithelial electrical resistance (TEER) were measured before and 24 h after NM exposure. Fixed cultures were stained for hematoxylin and eosin or live/dead staining. Culture media were analyzed for 11 growth factors. A 1-h vapor exposure to greater than or equal to 50 μM NM increased supernatant LDH, decreased TEER, and caused airway epithelial cell detachment. Endothelial cell death occurred at 500 μM NM. Vascular endothelial growth factor A (VEGF-A) and placental growth factor (PlGF) expression increased in 500 μM NM-exposed cultures compared with PBS-exposed control cultures. NM vapor exposure causes differential cytotoxicity to airway epithelial and endothelial injury in culture. Increased VEGF-A and PlGF expression occurred acutely in airway cocultures. Future studies are required to validate the role of VEGF signaling in mustard-induced airway pathology.

Mitral valve leaflet response to ischaemic mitral regurgitation: from gene expression to tissue remodelling

Ischaemic mitral regurgitation (IMR), a frequent complication following myocardial infarction (MI), leads to higher mortality and poor clinical prognosis if untreated. Accumulating evidence suggests that mitral valve (MV) leaflets actively remodel post MI, and this remodelling increases both the severity of IMR and the occurrence of MV repair failures. However, the mechanisms of extracellular matrix maintenance and modulation by MV interstitial cells (MVICs) and their impact on MV leaflet tissue integrity and repair failure remain largely unknown. Herein, we sought to elucidate the multiscale behaviour of IMR-induced MV remodelling using an established ovine model. Leaflet tissue at eight weeks post MI exhibited significant permanent plastic radial deformation, eliminating mechanical anisotropy, accompanied by altered leaflet composition. Interestingly, no changes in effective collagen fibre modulus were observed, with MVICs slightly rounder, at eight weeks post MI. RNA sequencing indicated that YAP-induced genes were elevated at four weeks post MI, indicating elevated mechanotransduction. Genes related to extracellular matrix organization were downregulated at four weeks post MI when IMR occurred. Transcriptomic changes returned to baseline by eight weeks post MI. This multiscale study suggests that IMR induces plastic deformation of the MV with no functional damage to the collagen fibres, providing crucial information for computational simulations of the MV in IMR.

Association Between Single Nucleotide Polymorphisms in NFATC1 Signaling Pathway Genes and Susceptibility to Congenital Heart Disease in the Chinese Population

The nuclear factor of activated T lymphocytes (NFATC1) signaling has been demonstrated to play important roles in cardiac valve and septal development. Genetic variants in genes involved in NFATC1 signaling may affect their expression and promote the formation of congenital heart disease (CHD). The goal of this study was to investigate the associations of single nucleotide polymorphism (SNP) in seven genes (NFATC1, VEGFR, VEGF, RANKL, FGFR1, BCL-6 and ZNRD1) with the risk of CHD. Twenty-nine polymorphisms were genotyped by using MassARRAY RS1000 platform in 277 CHD child patients and 293 controls from the Henan Province in China. Fours SNPs were excluded for the association analysis because of deviation from the Hardy-Weinberg equilibrium. Of the 25 SNPs, only two were found to be significantly associated with increased CHD risk after Bonferroni correction (RANKL, rs4531631: homozygous, AA vs. GG; OR 2.38, 95 % CI 1.40-4.07, p = 0.001; recessive, AA vs. AG + GG; OR 2.54, 95 % CI 1.53-4.22, p = 0.0003; FGFR1, rs13317: recessive, CC vs. CT + TT; OR 2.06, 95 % CI 1.30-3.25, p = 0.00196). Our findings suggest rs4531631 and rs13317 may be potential biomarkers for genetic diagnosis and treatment of CHD.

NFATc1 regulates cell proliferation, migration, and invasion of ovarian cancer SKOV3 cells in vitro and in vivo

NFATc1 (nuclear factor of activated T‑cells c1) is associated with malignancy in several cancer models. However, the expression and function of NFATc1 in ovarian cancer remain elusive. In the present study, we investigated the role of NFATc1 in human epithelial ovarian cancer (EOC) using human ovarian adenocarcinoma SKOV3 cells and patient characteristics. NFATc1 expression was silenced by siRNA in the SKOV3 ovarian cancer cell line and in human ovarian cancer nude mouse xenografts. Real‑time PCR, western blotting, immunohistochemical staining, MTT, flow cytometry, transwell, erasion trace and mouse assays were used to detect NFATc1 expression, cell proliferation, apoptosis, cell invasion and migration, tumor growth and angiogenesis. Survival analysis was performed to assess the correlation between NFATc1 expression and survival. NFATc1 was overexpressed in the SKOV3 ovarian cancer cell line and in human serous/mucinous ovarian cancer tissues. The silencing of NFATc1 expression by siRNA reduced cell proliferation and migration and promoted apoptosis in vitro and decreased the ovarian cancer cell tumorigenesis in vivo in nude mice. NFATc1 overexpression in high‑grade serous ovarian carcinomas was an independent prognostic factor of poor overall survival and of early relapse (P<0.01) in a univariate analysis. Our present data provide evidence that NFATc1 is overexpressed in human serous/mucinous ovarian cancer and is associated with a poor prognosis. NFATc1 silencing regulates the cell cycle, apoptosis, invasion and migration. NFATc1 thus has the potential to be a therapeutic target and to be used in EOC diagnosis and prognosis.

The effect of NFATc1 on vascular generation and the possible underlying mechanism in epithelial ovarian carcinoma

We investigated the effect of nuclear factor of activated T cells c1 (NFATc1) on the growth and vascular generation of human ovarian carcinoma SKOV3 cell-transplanted tumors in nude mice and explored the possible underlying mechanism. NFATc1 siRNA was transfected into the SKOV3 cells, which were then subjected to immunofluorescence tests and real-time reverse transcription polymerase chain reaction (RT-PCR) to determine the transfection-induced inhibition rate. The tumor volumes in the nude mice in all groups were measured to determine the in vivo antitumor effect of NFATc1 siRNA. Immunohistochemical (IHC) methods were employed to detect NFATc1 expression in tumor tissue, combined with cytokeratin (CK) staining to label the epithelial origin of the tumor tissue. CD34 and podoplanin were used as markers for labeling microvessels and microlymphatic vessels, respectively. The densities of microvessels and microlymphatic vessels in each group were calculated and statistically analyzed. RT-PCR and western blotting were performed to detect the protein and mRNA expression levels of NFATc1, the ELR+ CXC chemokine interleukin (IL)-8, fibroblast growth factor-2 (FGF-2), and platelet-derived growth factor BB (PDGF BB) in xenografted tumor tissue in all groups. NFATc1 was highly expressed in tumor tissue in the control groups. The intervention group exhibited a tumor growth inhibition rate of 57.08% and presented a lower tumor weight and volume compared with the two control groups. In the control groups, the microvessel densities were 12.00 ± 1.65 and 11.47 ± 0.32, respectively, and the microlymphatic vessel densities were 10.03 ± 0.96 and 9.95 ± 1.12; these values were significantly higher than in the intervention group. RT-PCR and western blot shows that NFATc1 siRNA could markedly suppress the expression of IL-8, FGF-2 and PDGF BB at the mRNA and the protein level. In conclusion, it was shown that NFATc1 siRNA significantly suppresses the growth and vascular generation of SKOV3 human ovarian carcinoma cell-transplanted tumors subcutaneously xenografted into nude mice. The downregulation of the expression of IL-8, FGF-2 and PDGF BB may be one of the mechanisms underlying the above inhibitory effects.

The Far Side of Vascular Injury

Substances historically thought to cause direct vascular injury in laboratory animals are a heterogeneous group of toxic agents with varied mechanisms of action. Morphologically, the reviewed agents can be broadly categorized into those targeting endothelial cell (ECs) and those targeting smooth muscle cells (SMCs). Anticancer drugs, immunosuppressants, and heavy metals are targeting primarily ECs while allylamine, β-aminopropionitrile, and mitogen-activated protein kinase kinase inhibitors affect mainly SMCs. It is now recognized that the pathogenicity of some of these agents is often mediated through intermediary events, particularly vasoconstriction. There are clear similarities in the clinical and microscopic findings associated with many of these agents in animals and man, allowing the use of animal models to investigate mechanisms and pathogenesis. The molecular pathogenic mechanisms and comparative morphology in animals and humans will be reviewed.

Reciprocal interactions between mitral valve endothelial and interstitial cells reduce endothelial-to-mesenchymal transition and myofibroblastic activation

Thickening of mitral leaflets, endothelial-to-mesenchymal transition (EndMT), and activated myofibroblast-like interstitial cells have been observed in ischemic mitral valve regurgitation. We set out to determine if interactions between mitral valve endothelial cells (VEC) and interstitial cells (VIC) might affect these alterations. We used in vitro co-culture in Transwell™ inserts to test the hypothesis that VIC secrete factors that inhibit EndMT and conversely, that VEC secrete factors that mitigate the activation of VIC to a myofibroblast-like, activated phenotype. Primary cultures and clonal populations of ovine mitral VIC and VEC were used. Western blot, quantitative reverse transcriptase PCR (qPCR) and functional assays were used to assess changes in cell phenotype and behavior. VIC or conditioned media from VIC inhibited transforming growth factorβ (TGFβ)-induced EndMT in VEC, as indicated by reduced expression of EndMT markers α-smooth muscle actin (α-SMA), Slug, Snai1 and MMP-2 and maintained ability of VEC to mediate leukocyte adhesion, an important endothelial function. VEC or conditioned media from VEC reversed the spontaneous cell culture-induced change in VIC to an activated phenotype, as indicated by reduced expression of α-SMA and type I collagen, increased expression chondromodulin-1 (Chm1), and reduced contractile activity. These results demonstrate that mitral VEC and VIC secrete soluble factors that can reduce VIC activation and inhibit TGFβ-driven EndMT, respectively. These findings suggest that the endothelium of the mitral valve is critical for the maintenance of a quiescent VIC phenotype and that, in turn, VIC prevent EndMT. We speculate that disturbance of the ongoing reciprocal interactions between VEC and VICs in vivo may contribute to the thickened and fibrotic leaflets observed in ischemic mitral regurgitation, and in other types of valve disease.

Thymosin beta4 regulates cardiac valve formation via endothelial-mesenchymal transformation in zebrafish embryos

Thymosin beta4 (TB4) has multiple functions in cellular response in processes as diverse as embryonic organ development and the pathogeneses of disease, especially those associated with cardiac coronary vessels. However, the specific roles played by TB4 during heart valve development in vertebrates are largely unknown. Here, we identified a novel function of TB4 in endothelialmesenchymal transformation (EMT) in cardiac valve endocardial cushions in zebrafish. The expressions of thymosin family members in developing zebrafish embryos were determined by whole mount in situ hybridization. Of the thymosin family members only zTB4 was expressed in the developing heart region. Cardiac valve development at 48 h post fertilization was defected in zebrafish TB4 (zTB4) morpholino-injected embryos (morphants). In zTB4 morphants, abnormal linear heart tube development was observed. The expressions of bone morphogenetic protein (BMP) 4, notch1b, and hyaluronic acid synthase (HAS) 2 genes were also markedly reduced in atrio-ventricular canal (AVC). Endocardial cells in the AVC region were stained with anti-Zn5 antibody reactive against Dm-grasp (an EMT marker) to observe EMT in developing cardiac valves in zTB4 morphants. EMT marker expression in valve endothelial cells was confirmed after transfection with TB4 siRNA in the presence of transforming growth factor β (TGFβ) by RT-PCR and immunofluorescent assay. Zn5-positive endocardial AVC cells were not observed in zTB4 morphants, and knockdown of TB4 suppressed TGF-β-induced EMT in ovine valve endothelial cells. Taken together, our results demonstrate that TB4 plays a pivotal role in cardiac valve formation by increasing EMT.1.

Nuclear factor of activated T cells - a transcription factor family as critical regulator in lung and colon cancer

Nuclear factor of activated T cells (NFAT) was first identified as a transcription factor which is activated upon T cell stimulation. Subsequent studies uncovered that a whole family of individual NFAT proteins exists with pleiotropic functions not only in immune but also in nonimmune cells. However, dysregulation of NFAT thereby favors malignant growth and cancer. Summarizing the recent advances in understanding how individual NFAT factors regulate the immune system, this review gives new insights into the critical role of NFAT in cancer development with special focus on inflammation-associated colorectal cancer.

Runx2 protein stabilizes hypoxia-inducible factor-1α through competition with von Hippel-Lindau protein (pVHL) and stimulates angiogenesis in growth plate hypertrophic chondrocytes

The regulation of hypoxia-inducible factor-1α (HIF-1α) during endochondral bone formation is not fully understood. Here, we investigated the cross-talk between HIF-1α and Runt-related transcription factor 2 (Runx2) in the growth plate. Runx2 caused the accumulation of HIF-1α protein in ATDC5 chondrocytes and HEK293 cells under normoxic conditions. Runx2 also increased the nuclear translocation of HIF-1α when coexpressed in HEK293 cells and interacted with HIF-1α at the oxygen-dependent degradation domain (ODDD). In addition, Runx2 competed with von Hippel-Lindau tumor suppressor protein by directly binding to ODDD-HIF-1α and significantly inhibited the ubiquitination of HIF-1α, even though Runx2 did not change the hydroxylation status of HIF-1α. Furthermore, overexpression of Runx2 resulted in the significant enhancement of vascular endothelial growth factor (VEGF) promoter reporter activity and protein secretion. Runx2 significantly increased angiogenic activity in human umbilical vein endothelial cells in vitro. In wild-type mice, HIF-1α and Runx2 were colocalized in hypertrophic chondrocytes in which the cluster of differentiation 31 (CD31) protein was expressed at embryonic day 15.5 (E15.5). In contrast, the expression of HIF-1α was markedly reduced in areas of CD31 expression in Runx2(-/-) mice. These results suggest that Runx2 stabilizes HIF-1α by binding to ODDD to block the interaction between von Hippel-Lindau protein and HIF-1α. In conclusion, Runx2, HIF-1α, and VEGF may regulate vascular angiogenesis spatially and temporally in the hypertrophic zone of the growth plate during endochondral bone formation.

Mechanisms of function and disease of natural and replacement heart valves

Over the past several decades, there has been substantial progress toward understanding the mechanisms of heart valve function and dysfunction. This review summarizes an evolving conceptual framework of heart valve functional structure, developmental biology, and pathobiology and explores the implications of key insights. I emphasize: (a) valve cell and extracellular matrix biology and the impact of biomechanical factors on function, homeostasis, environmental adaptation, and key pathological processes; (b) the role of developmental processes, valvular cell behavior, and extracellular matrix remodeling in congenital and acquired valve abnormalities; and (c) the cell/matrix biology of degeneration in replacement tissue valves. I also summarize how these considerations may ultimately inform the potential for prevention and treatment of major diseases and potentially therapeutic regeneration of the cardiac valves. Recent advances and opportunities for research and clinical translation are highlighted.

Altered versican cleavage in ADAMTS5 deficient mice; a novel etiology of myxomatous valve disease

In fetal valve maturation the mechanisms by which the relatively homogeneous proteoglycan-rich extracellular matrix (ECM) of endocardial cushions is replaced by a specialized and stratified ECM found in mature valves are not understood. Therefore, we reasoned that uncovering proteases critical for 'remodeling' the proteoglycan rich (extracellular matrix) ECM may elucidate novel mechanisms of valve development. We have determined that mice deficient in ADAMTS5, (A Disintegrin-like And Metalloprotease domain with ThromboSpondin-type 1 motifs) which we demonstrated is expressed predominantly by valvular endocardium during cardiac valve maturation, exhibited enlarged valves. ADAMTS5 deficient valves displayed a reduction in cleavage of its substrate versican, a critical cardiac proteoglycan. In vivo reduction of versican, in Adamts5(-/-) mice, achieved through Vcan heterozygosity, substantially rescued the valve anomalies. An increase in BMP2 immunolocalization, Sox9 expression and mesenchymal cell proliferation were observed in Adamts5(-/-) valve mesenchyme and correlated with expansion of the spongiosa (proteoglycan-rich) region in Adamts5(-/-) valve cusps. Furthermore, these data suggest that ECM remodeling via ADAMTS5 is required for endocardial to mesenchymal signaling in late fetal valve development. Although adult Adamts5(-/-) mice are viable they do not recover from developmental valve anomalies and have myxomatous cardiac valves with 100% penetrance. Since the accumulation of proteoglycans is a hallmark of myxomatous valve disease, based on these data we hypothesize that a lack of versican cleavage during fetal valve development may be a potential etiology of adult myxomatous valve disease.

Heart valve tissue engineering: quo vadis?

Surgical replacement of diseased heart valves by mechanical and tissue valve substitutes is now commonplace and generally enhances survival and quality of life. However, a fundamental problem inherent to the use of existing mechanical and biological prostheses in the pediatric population is their failure to grow, repair, and remodel. A tissue engineered heart valve could, in principle, accommodate these requirements, especially somatic growth. This review provides a brief overview of the field of heart valve tissue engineering, with emphasis on recent studies and evolving concepts, especially those that establish design criteria and key hurdles that must be surmounted before clinical implementation.

Cyclosporin A and atherosclerosis--cellular pathways in atherogenesis

Cyclosporin A (CsA) is an immunosuppressant drug widely used in organ transplant recipients and people with autoimmune disorders. Long term treatment with CsA is associated with many side effects including hyperlipidemia and an increased risk of atherosclerosis. While its immunosuppressive effects are closely linked to its effects on T cell activation via the inhibition of the nuclear factor of activated T cells (NFAT) pathway, the precise mechanisms underlying its cardiovascular effects appear to involve multiple pathways additional to those relevant for immunosuppression. These include inhibition of calcineurin activity and intracellular cyclophilin peptidylprolyl isomerase and chaperone activities, inhibition of pro-inflammatory extracellular cyclophilin A, and NFAT-independent transcriptional effects. CsA demonstrates complex effects on lipoprotein metabolism and bile acid production, and affects endothelial cells, smooth muscle cells and macrophages, all of which are critical to the atherosclerotic process. Interpretation of the available data is hampered as many experimental models are used to study the effects of CsA in vivo and in vitro, leading to diverse and often contradictory findings. In this review we will describe the cellular mechanisms related to CsA-induced hyperlipidemia and atherosclerosis, with a focus on identifying pro-atherogenic pathways that are distinct from those relevant to its immunosuppressant effects. The potential of CsA analogues to avoid such sequelae will be discussed.