PDGFRα: Expression and Function during Mitral Valve Morphogenesis

Mitral valve prolapse (MVP) is a common form of valve disease and can lead to serious secondary complications. The recent identification of MVP causal mutations in primary cilia-related genes has prompted the investigation of cilia-mediated mechanisms of disease inception. Here, we investigate the role of platelet-derived growth factor receptor-alpha (PDGFRα), a receptor known to be present on the primary cilium, during valve development using genetically modified mice, biochemical assays, and high-resolution microscopy. While PDGFRα is expressed throughout the ciliated valve interstitium early in development, its expression becomes restricted on the valve endocardium by birth and through adulthood. Conditional ablation of Pdgfra with Nfatc1-enhancer Cre led to significantly enlarged and hypercellular anterior leaflets with disrupted endothelial adhesions, activated ERK1/2, and a dysregulated extracellular matrix. In vitro culture experiments confirmed a role in suppressing ERK1/2 activation while promoting AKT phosphorylation. These data suggest that PDGFRα functions to suppress mesenchymal transformation and disease phenotypes by stabilizing the valve endocardium through an AKT/ERK pathway.

Download Full-text

Zyxin Regulates Cell Migration and Differentiation in EMT during Chicken AV Valve Morphogenesis

Microscopy and Microanalysis ◽

10.1017/s1431927613001633 ◽

2013 ◽

Vol 19 (4) ◽

pp. 842-854 ◽

Cited By ~ 2

Author(s):

Na Li ◽

Richard L. Goodwin ◽

Jay D. Potts

Keyword(s):

Cell Migration ◽

Collagen Gel ◽

Mesenchymal Cells ◽

Valve Development ◽

Focal Adhesion Protein ◽

Endocardial Cell ◽

Mesenchymal Transformation ◽

And Function ◽

Valve Formation

AbstractDuring heart valve development, epithelial–mesenchymal transformation (EMT) is a key process for valve formation. EMT leads to the generation of mesenchymal cells that will eventually become the interstitial cells (fibroblasts) of the mature valve. During EMT, cell architecture and motility change markedly; significant changes are also observed in various signaling pathways. Here we systematically examined the expression, localization, and function of zyxin, a focal adhesion protein, in EMT during atrioventricular (AV) valve morphogenesis. Expression and localization studies showed that zyxin was expressed in the AV canal region during crucial stages of valve development. An in vitro 3D collagen gel culture system was used to determine zyxin function either after siRNA gene knockdown or after overexpression. Our studies revealed that zyxin overexpression inhibited endocardial cell migration and cell differentiation and also led to a decrease in the number of migrating mesenchymal cells. Moreover, correlative cytoskeletal changes were apparent in response to both overexpression and knockdown treatments. Thus, zyxin appears to play a role as a regulator of cell migration and differentiation during EMT in chicken AV valve formation.

Download Full-text

Primary Cilia Blockage Promotes the Malignant Behaviors of Hepatocellular Carcinoma via Induction of Autophagy

BioMed Research International ◽

10.1155/2019/5202750 ◽

2019 ◽

Vol 2019 ◽

pp. 1-14

Author(s):

Lian Liu ◽

Jia-Qi Sheng ◽

Mu-Ru Wang ◽

Yun Gan ◽

Xiao-Li Wu ◽

...

Keyword(s):

Hepatocellular Carcinoma ◽

Primary Cilia ◽

The Cancer Genome Atlas ◽

Migration And Invasion ◽

Serum Starvation ◽

Autophagic Flux ◽

And Function ◽

Hcc Cells

Primary cilia are organelles protruding from cell surface into environment that function in regulating cell cycle and modulating cilia-related signal. Primary ciliogenesis and autophagy play important roles in tumorigenesis. However, the functions and interactions between primary cilia and autophagy in hepatocellular carcinoma (HCC) have not been reported yet. Here, we aimed to investigate the relationship and function of primary cilia and autophagy in HCC. In vitro, we showed that serum starvation stimuli could trigger primary ciliogenesis in HCC cells. Blockage of primary ciliogenesis by IFT88 silencing enhanced the proliferation, migration, and invasion ability of HCC cells. In addition, inhibition of primary cilia could positively regulate autophagy. However, the proliferation, migration, and invasion ability which were promoted by IFT88 silencing could be partly reversed by inhibition of autophagy. In vivo, interference of primary cilia led to acceleration of tumor growth and increase of autophagic flux in xenograft HCC mouse models. Moreover, IFT88 high expression or ATG7 low expression in HCC tissues was correlated with longer survival time indicated by the Cancer Genome Atlas (TCGA) analysis. In conclusion, our study demonstrated that blockage of primary ciliogenesis by IFT88 silencing had protumor effects through induction of autophagy in HCC. These findings define a newly recognized role of primary cilia and autophagy in HCC.

Download Full-text

Platelet-Derived Growth Factor Receptor Alpha as a Marker of Mesenchymal Stem Cells in Development and Stem Cell Biology

Stem Cells International ◽

10.1155/2015/362753 ◽

2015 ◽

Vol 2015 ◽

pp. 1-8 ◽

Cited By ~ 33

Author(s):

Ramin M. Farahani ◽

Munira Xaymardan

Keyword(s):

Stem Cells ◽

Mesenchymal Stem Cells ◽

Stem Cell ◽

Cell Biology ◽

Growth Factor Receptor ◽

Stem Cell Marker ◽

Factor Receptor Alpha ◽

Lines Of Evidence

Three decades on, the mesenchymal stem cells (MSCs) have been intensively researched on the bench top and used clinically. However, ambiguity still exists in regard to their anatomical locations, identities, functions, and extent of their differentiative abilities. One of the major impediments in the quest of the MSC research has been lack of appropriatein vivomarkers. In recent years, this obstacle has been resolved to some degree as PDGFRαemerges as an important mesenchymal stem cell marker. Accumulating lines of evidence are showing that the PDGFRα+cells reside in the perivascular locations of many adult interstitium and fulfil the classic concepts of MSCsin vitroandin vivo. PDGFRαhas long been recognised for its roles in the mesoderm formation and connective tissue development during the embryogenesis. Current review describes the lines of evidence regarding the role of PDGFRαin morphogenesis and differentiation and its implications for MSC biology.

Download Full-text

Quercetin Preservesβ-Cell Mass and Function in Fructose-Induced Hyperinsulinemia through Modulating Pancreatic Akt/FoxO1 Activation

Evidence-based Complementary and Alternative Medicine ◽

10.1155/2013/303902 ◽

2013 ◽

Vol 2013 ◽

pp. 1-12 ◽

Cited By ~ 10

Author(s):

Jian-Mei Li ◽

Wei Wang ◽

Chen-Yu Fan ◽

Ming-Xing Wang ◽

Xian Zhang ◽

...

Keyword(s):

Serum Insulin ◽

Cell Mass ◽

Janus Kinase ◽

Cytokine Signaling ◽

Akt Phosphorylation ◽

High Fructose ◽

Stat3 Phosphorylation ◽

And Function

Fructose-induced hyperinsulinemia is associated with insulin compensative secretion and predicts the onset of type 2 diabetes. In this study, we investigated the preservation of dietary flavonoid quercetin on pancreaticβ-cell mass and function in fructose-treated rats and INS-1β-cells. Quercetin was confirmed to reduce serum insulin and leptin levels and blockade islet hyperplasia in fructose-fed rats. It also prevented fructose-inducedβ-cell proliferation and insulin hypersecretion in INS-1β-cells. High fructose increased forkhead box protein O1 (FoxO1) expressionsin vivoandin vitro, which were reversed by quercetin. Quercetin downregulated Akt and FoxO1 phosphorylation in fructose-fed rat islets and increased the nuclear FoxO1 levels in fructose-treated INS-1β-cells. The elevated Akt phosphorylation in fructose-treated INS-1β-cells was also restored by quercetin. Additionally, quercetin suppressed the expression of pancreatic and duodenal homeobox 1 (Pdx1) and insulin gene (Ins1 and Ins2)in vivoandin vitro. In fructose-treated INS-1β-cells, quercetin elevated the reduced janus kinase 2/signal transducers and activators of transcription 3 (Jak2/Stat3) phosphorylation and suppressed the increased suppressor of cytokine signaling 3 (Socs3) expression. These results demonstrate that quercetin protectsβ-cell mass and function under high-fructose induction through improving leptin signaling and preserving pancreatic Akt/FoxO1 activation.

Download Full-text

Prognostic Relevance and Function of MSX2 in Colorectal Cancer

Journal of Diabetes Research ◽

10.1155/2017/3827037 ◽

2017 ◽

Vol 2017 ◽

pp. 1-10 ◽

Cited By ~ 2

Author(s):

Jiancheng Liu ◽

Huaying An ◽

Wei Yuan ◽

Qiang Feng ◽

Lianzhen Chen ◽

...

Keyword(s):

Colorectal Cancer ◽

Clinical Stage ◽

Total Mortality ◽

Test Analysis ◽

Akt Phosphorylation ◽

Protein Levels ◽

Patients With Diabetes ◽

Chi Squared ◽

And Function

Colorectal cancer patients with diabetes had the high risks of total mortality. High expression of MSX2 is related to development of diabetes. There are few reports about the clinical implications and function of MSX2 in colorectal cancer (CRC). The purpose of this study is to investigate the relationship between the expression of MSX2 and clinical relevance and discover the possible mechanism of MSX2 in the development of CRC. Compared with adjacent tissues, the expression of MSX2 was higher in tumor tissues in both mRNA and protein levels (P<0.01). Kaplan-Meier survival analysis showed that high mRNA expression of MSX2 was associated with short survival time (P=0.013). Chi-squared test analysis indicated that MSX2 expression was related to tumor size (P=0.04), tumor locus (P=0.025), clinical stage (P<0.001), tumor invasion (P=0.003), lymphatic metastasis (P=0.01), and distant metastasis (P=0.033). In vitro experiments demonstrated that knockdown of MSX2 expression attenuated cell proliferation and invasion, promoted cell cycle arrest and apoptosis, and inactivated Akt phosphorylation. In conclusion, MSX2 played a crucial role in the progression of CRC and may be a potential novel prognostic factor and therapeutic target for CRC therapy. Our work may provide certain enlightenment for investigating the mechanism of MSX2 in the process of diabetes.

Download Full-text

Developmental Regulation of Human Cytomegalovirus Receptors in Cytotrophoblasts Correlates with Distinct Replication Sites in the Placenta

Journal of Virology ◽

10.1128/jvi.02748-06 ◽

2007 ◽

Vol 81 (9) ◽

pp. 4701-4712 ◽

Cited By ~ 54

Author(s):

Ekaterina Maidji ◽

Olga Genbacev ◽

Hsin-Ti Chang ◽

Lenore Pereira

Keyword(s):

Developmental Regulation ◽

Growth Factor Receptor ◽

Chorionic Villi ◽

Susceptibility To Infection ◽

Focal Infection ◽

Replication Sites ◽

Epidermal Growth ◽

And Function

ABSTRACT Cytomegalovirus (CMV), the major viral cause of congenital disease, infects the uterus and developing placenta and spreads to the fetus throughout gestation. Virus replicates in invasive cytotrophoblasts in the decidua, and maternal immunoglobulin G (IgG)-CMV virion complexes, which are transcytosed by the neonatal Fc receptor across syncytiotrophoblasts, infect underlying cytotrophoblasts in chorionic villi. Immunity is central to protection of the placenta-fetal unit: infection can occur when IgG has a low neutralizing titer. Here we used immunohistochemical and function-blocking methods to correlate infection in the placenta with expression of potential CMV receptors in situ and in vitro. In placental villi, syncytiotrophoblasts express the virion receptor epidermal growth factor receptor (EGFR) but lack integrin coreceptors, and virion uptake occurs without replication. Focal infection can occur when transcytosed virions reach EGFR-expressing cytotrophoblasts that selectively initiate expression of αV integrin. In cell columns, proximal cytotrophoblasts lack receptors and distal cells express integrins α1β1 and αVβ3, enabling virion attachment. In the decidua, invasive cytotrophoblasts expressing coreceptors upregulate EGFR, thereby dramatically increasing susceptibility to infection. Our findings indicate that virion interactions with cytotrophoblasts expressing receptors in the placenta (i) change as the cells differentiate and (ii) correlate with spatially distinct sites of CMV replication in maternal and fetal compartments.

Download Full-text

Releasing prophase arrest in zebrafish oocyte: synergism between maturational steroid and Igf1

Reproduction ◽

10.1530/rep-15-0389 ◽

2016 ◽

Vol 151 (1) ◽

pp. 59-72 ◽

Cited By ~ 15

Author(s):

Debabrata Das ◽

Soumojit Pal ◽

Sudipta Maitra

Keyword(s):

Growth Factor Receptor ◽

Germinal Vesicle ◽

Germinal Vesicle Breakdown ◽

Akt Phosphorylation ◽

Physiological Relevance ◽

17Β Estradiol ◽

Epidermal Growth ◽

Membrane Progestin Receptor

Binding of 17β-estradiol (E2) to novel G-protein coupled receptor, Gper1, promotes intra-oocyte adenylyl cyclase activity and transactivates epidermal growth factor receptor to ensure prophase-I arrest. Although involvement of either membrane progestin receptor (mPR) or Igf system has been implicated in regulation of meiosis resumption, possibility of concurrent activation and potential synergism between 17α,20β-dihydroxy-4-pregnen-3-one (DHP)- and Igf-mediated signalling cascades in alleviating E2 inhibition of oocyte maturation (OM) has not been investigated. Here using zebrafish (Danio rerio) defolliculated oocytes, we examined the effect of DHP and Igf1, either alone or in combination, in presence or absence of E2, on OM in vitro. While priming of denuded oocytes with E2 blocked spontaneous maturation, co-treatment with DHP (3 nM) and Igf1 (10 nM), but not alone, reversed E2 inhibition and promoted a robust increase in germinal vesicle breakdown (GVBD). Although stimulation with either Igf1 or DHP promoted Akt phosphorylation, pharmacological inhibition of PI3K/Akt signalling prevented Igf1-induced GVBD but delayed DHP action till 4–5 h of incubation. Moreover, high intra-oocyte cAMP attenuates both DHP and Igf1-mediated OM and co-stimulation with DHP and Igf1 could effectively reverse E2 action on PKA phosphorylation. Interestingly, data from in vivo studies reveal that heightened expression of igf1, igf3 transcripts in intact follicles corresponded well with elevated phosphorylation of Igf1r and Akt, mPRa immunoreactivity, PKA inhibition and accelerated GVBD response just prior to ovulation. This indicates potential synergism between maturational steroid and Igf1 which might have physiological relevance in overcoming E2 inhibition of meiosis resumption in zebrafish oocytes.

Download Full-text

FIP1L1/PDGFRα synergizes with SCF to induce systemic mastocytosis in a murine model of chronic eosinophilic leukemia/hypereosinophilic syndrome

Blood ◽

10.1182/blood-2007-11-126268 ◽

2008 ◽

Vol 112 (6) ◽

pp. 2500-2507 ◽

Cited By ~ 8

Author(s):

Yoshiyuki Yamada ◽

Abel Sanchez-Aguilera ◽

Eric B. Brandt ◽

Melissa McBride ◽

Nabeel J. H. Al-Moamen ◽

...

Keyword(s):

Bone Marrow ◽

Fusion Gene ◽

Systemic Mastocytosis ◽

Hypereosinophilic Syndrome ◽

Growth Factor Receptor ◽

Hematopoietic Stem ◽

Chronic Eosinophilic Leukemia ◽

Factor Receptor Alpha

Abstract Expression of the fusion gene FIP1-like 1/platelet-derived growth factor receptor alpha (FIP1L1/PDGFRα, F/P) and dysregulated c-kit tyrosine kinase activity are associated with systemic mastocytosis (SM) and chronic eosinophilic leukemia (CEL)/hypereosinophilic syndrome (HES). We analyzed SM development and pathogenesis in a murine CEL model induced by F/P in hematopoietic stem cells and progenitors (HSCs/Ps) and T-cell overexpression of IL-5 (F/P-positive CEL mice). These mice had more mast cell (MC) infiltration in the bone marrow (BM), spleen, skin, and small intestine than control mice that received a transplant of IL-5 transgenic HSCs/Ps. Moreover, intestinal MC infiltration induced by F/P expression was severely diminished, but not abolished, in mice injected with neutralizing anti–c-kit antibody, suggesting that endogenous stem cell factor (SCF)/c-kit interaction synergizes with F/P expression to induce SM. F/P-expressing BM HSCs/Ps showed proliferation and MC differentiation in vitro in the absence of cytokines. SCF stimulated greater migration of F/P-expressing MCs than mock vector–transduced MCs. F/P-expressing bone marrow–derived mast cells (BMMCs) survived longer than mock vector control BMMCs in cytokine-deprived conditions. The increased proliferation and survival correlated with increased SCF-induced Akt activation. In summary, F/P synergistically promotes MC development, activation, and survival in vivo and in vitro in response to SCF.

Download Full-text

Expression and functional studies of the GDNF family receptor alpha 3 in the pancreas

Journal of Molecular Endocrinology ◽

10.1530/jme-15-0213 ◽

2015 ◽

Vol 56 (2) ◽

pp. 77-90 ◽

Cited By ~ 2

Author(s):

Laure Nivlet ◽

Joel Herrmann ◽

Delia Esteban Martin ◽

Aline Meunier ◽

Christophe Orvain ◽

...

Keyword(s):

Islet Cell ◽

Cell Formation ◽

Cell Development ◽

Β Cells ◽

Receptor Alpha ◽

Functional Studies ◽

Factor Receptor Alpha ◽

And Function ◽

Deficient Mice

The generation of therapeutic β-cells from human pluripotent stem cells relies on the identification of growth factors that faithfully mimic pancreatic β-cell development in vitro. In this context, the aim of the study was to determine the expression and function of the glial cell line derived neurotrophic factor receptor alpha 3 (GFRα3) and its ligand artemin (Artn) in islet cell development and function. GFRα3 and Artn expression were characterized by in situ hybridization, immunochemistry, and qRT-PCR. We used GFRα3-deficient mice to study GFRα3 function and generated transgenic mice overexpressing Artn in the embryonic pancreas to study Artn function. We found that GFRα3 is expressed at the surface of a subset of Ngn3-positive endocrine progenitors as well as of embryonic α- and β-cells, while Artn is found in the pancreatic mesenchyme. Adult β-cells lack GFRα3 but α-cells express the receptor. GFRα3 was also found in parasympathetic and sympathetic intra-islet neurons as well as in glial cells in the embryonic and adult pancreas. The loss of GFRα3 or overexpression of Artn has no impact on Ngn3 and islet cell formation and maintenance in the embryo. Islet organization and innervation as well as glucose homeostasis is normal in GFRα3-deficient mice suggesting functional redundancy.

Download Full-text

Glutamylation on α-Tubulin Is Not Essential but Affects the Assembly and Functions of a Subset of Microtubules in Tetrahymena thermophila

Eukaryotic Cell ◽

10.1128/ec.00084-08 ◽

2008 ◽

Vol 7 (8) ◽

pp. 1362-1372 ◽

Cited By ~ 65

Author(s):

Dorota Wloga ◽

Krzysztof Rogowski ◽

Neeraj Sharma ◽

Juliette Van Dijk ◽

Carsten Janke ◽

...

Keyword(s):

Site Directed Mutagenesis ◽

Cell Multiplication ◽

Basal Bodies ◽

Tail Domain ◽

Major Mechanism ◽

Biochemical Assays ◽

Comparative Phylogeny ◽

A Chain ◽

And Function

ABSTRACT Tubulin undergoes glutamylation, a conserved posttranslational modification of poorly understood function. We show here that in the ciliate Tetrahymena, most of the microtubule arrays contain glutamylated tubulin. However, the length of the polyglutamyl side chain is spatially regulated, with the longest side chains present on ciliary and basal body microtubules. We focused our efforts on the function of glutamylation on the α-tubulin subunit. By site-directed mutagenesis, we show that all six glutamates of the C-terminal tail domain of α-tubulin that provide potential sites for glutamylation are not essential but are needed for normal rates of cell multiplication and cilium-based functions (phagocytosis and cell motility). By comparative phylogeny and biochemical assays, we identify two conserved tubulin tyrosine ligase (TTL) domain proteins, Ttll1p and Ttll9p, as α-tubulin-preferring glutamyl ligase enzymes. In an in vitro microtubule glutamylation assay, Ttll1p showed a chain-initiating activity while Ttll9p had primarily a chain-elongating activity. GFP-Ttll1p localized mainly to basal bodies, while GFP-Ttll9p localized to cilia. Disruption of the TTLL1 and TTLL9 genes decreased the rates of cell multiplication and phagocytosis. Cells lacking both genes had fewer cortical microtubules and showed defects in the maturation of basal bodies. We conclude that glutamylation on α-tubulin is not essential but is required for efficiency of assembly and function of a subset of microtubule-based organelles. Furthermore, the spatial restriction of modifying enzymes appears to be a major mechanism that drives differential glutamylation at the subcellular level.

Download Full-text