Fibronectin Adhesion Research Articles

Cells to Surgery Quiz: December 2018

Cells to Surgery Quiz: December 2018

Naringin ameliorates experimental diabetic renal fibrosis by inhibiting the ERK1/2 and JNK MAPK signaling pathways

AimsWith the specific pharmacological activities including anti-inflammation, anti-oxidant and hypoglycemic effects, Naringin may possess the potential to ameliorate diabetic nephropathy (DN). The purpose of this study was to investigate the anti-DN effect of Naringin and the molecular mechanism by which Naringin ameliorates diabetic renal fibrosis. MethodsThe effects of Naringin on fibronectin (FN) and intercellular adhesion molecule (ICAM-1) as well as the MAPK signaling pathways were detected in streptozotocin (STZ)-induced diabetic mice and high glucose (HG)-cultured glomerular mesangial cells (GMCs) respectively. ResultsNaringin significantly alleviated the renal fibrosis injury and suppressed the expression of FN and ICAM-1, with down-regulating the phosphorylation of ERK1/2 and JNK and inhibiting the activation of the downstream activating protein (AP-1). There were no meaningful difference between Naringin and the MAPK specific inhibitors. ConclusionInhibiting the ERK1/2 and JNK MAPK signaling pathways is probably a novel mechanism by which Naringin alleviates experimental diabetic renal fibrosis.

Ginsenoside-Rp3 inhibits platelet activation and thrombus formation by regulating MAPK and cyclic nucleotide signaling

Background & purposeGinseng (Panax ginseng C.A. Mayer) contains saponin fractions called ginsenosides, which are thought to be the main components responsible for its various pharmacological activities. Ginsenosides have cardioprotective and antiplatelet effects. In the present study, we evaluated the effects of ginsenoside Rp3 (G-Rp3) on platelet function. MethodsThe in vitro effects of G-Rp3 were evaluated on agonist-induced human and rat platelet aggregation, while [Ca2+]i mobilization, granule secretion, integrin αIIbβ3 activation, and clot retraction were assessed in rat platelets. Its effects on vasodilator-stimulated phosphoprotein (VASP) expression, phosphorylation of MAPK signaling molecules, and PI3K/Akt activation were also studied. Moreover, the tyrosine phosphorylation of components of the P2Y12 receptor downstream signaling pathway was also examined. The in vivo effects of G-Rp3 were studied using an acute pulmonary thromboembolism model and lung histopathology. Key resultsG-Rp3 significantly inhibited collagen, ADP, and thrombin-induced platelet aggregation. G-Rp3 elevated cAMP levels and VASP phosphorylation and suppressed agonist-induced [Ca2+]i mobilization, ATP release, and P-selectin expression along with fibrinogen binding to integrin αIIbβ3, fibronectin adhesion, and clot retraction. G-Rp3 also attenuated the phosphorylation of MAPK, Src, and PLCγ2 as well as PI3K/Akt activation. Furthermore, it inhibited tyrosine phosphorylation of the Src family kinases (Src, Fyn, and Lyn) and PLCγ2 and protected mice from thrombosis. Conclusion and implicationG-Rp3 modulates agonist-induced platelet activation and thrombus formation by inhibiting granule secretion, integrin αIIbβ3 activation, MAPK signaling, and Src, PLCγ2, and PI3K/Akt activation, and VASP stimulation. Our data suggest that G-Rp3 has therapeutic potential as a treatment for platelet-related cardiovascular disorders.

Progestin and AdipoQ Receptor 3 Upregulates Fibronectin and Intercellular Adhesion Molecule-1 in Glomerular Mesangial Cells via Activating NF-κB Signaling Pathway Under High Glucose Conditions.

Progestin and adipoQ receptor 3 (PAQR3), is a Golgi-anchored membrane protein containing seven transmembrane helices. It has been demonstrated that PAQR3 mediates insulin resistance, glucose and lipid metabolism, and inflammation. In addition, kidney inflammatory fibrosis is an important pathological feature of diabetic nephropathy (DN). Therefore, we aimed to investigate the role of PAQR3 in diabetic kidney fibrosis as well as inflammation in DN. The effect of PAQR3 on NF-κB signaling pathway, expressions of fibronectin (FN) and intercellular adhesion molecule-1 (ICAM-1) in glomerular mesangial cells (GMCs) cultured by high glucose (HG) were examined. Diabetic mouse and rat models were induced by streptozotocin (STZ). GMCs were treated with HG and transfected with PAQR3 plasmids or small-interfering RNA targeting PAQR3 or NF-κB. The protein levels of FN and ICAM-1 were examined by Western blotting, and the transcriptional activity and DNA binding activity of NF-κB were measured by dual luciferase reporter assay and electrophoretic mobility shift assay (EMSA). The interaction between PAQR3 and IKKβ (inhibitor of nuclear factor κB kinase β) was analyzed by co-immunoprecipitation. PAQR3 was increased in both STZ-induced diabetic models and HG-treated GMCs. PAQR3 overexpression further increased HG-induced FN and ICAM-1 upregulation. In contrast, silencing of PAQR3 suppressed the expressions of FN and ICAM-1. PAQR3 overexpression promoted the nuclear accumulation, DNA binding activity, and transcriptional activity of NF-κB. Mechanically, PAQR3 directly interacted with IKKβ. The upregulation effect of PAQR3 overexpression on the expressions of FN and ICAM-1 was abolished by the treatment of NF-κB siRNA or PDTC (ammonium pyrrolidinedithiocarbamate) in HG-treated GMCs. PAQR3 promotes the expressions of FN and ICAM-1 via activating NF-κB signaling pathway. Mechanistically, PAQR3 activates NF-κB signaling pathway to mediate kidney inflammatory fibrosis through direct interaction with IKKβ in DN.

Inhibitory effect of myocilin on fibronectin expression and adhesion in trabecular meshwork cells of glaucoma

Inhibitory effect of myocilin on fibronectin expression and adhesion in trabecular meshwork cells of glaucoma

Expression of fibronectin-binding protein of L. acidophilus NCFM and in vitro refolding to adhesion capable native-like protein from inclusion bodies

The ability of Lactobacilli to adhere to host epithelial surface and intestinal tracts is important for colonization and persistence of bacteria in the host gut. Extracellular matrix components like fibronectin, mucin, collagen and other adhesion molecules serve as substratum for attachment of bacteria. However, the precise structure, function and mechanism of binding of microbial surface adhesion proteins such as Fibronectin-binding protein (FBP) with host molecules remains unclear. This is primarily due to limitations in high expression of these proteins in biologically active form. To study adhesion of its FBP (64 kDa), the fbp gene of L. acidophilus NCFM was cloned and expressed in E. coli.However, the fibronectin-binding protein expressed in soluble form could not be purified by Ni-NTA affinity chromatography possibly because of partially buried Histidine tag in the recombinant fusion protein. Therefore, the protein was expressed as inclusion bodies (IBs) at 37 °C and solubilized in urea followed by purification in denatured form by Ni-NTA affinity chromatography. The purified denatured protein was refolded in vitro to structurally stable and biologically active form. The conformational properties of the refolded protein were studied by circular dichroism, which showed prominence of α+ β structural element. The refolded FBP also showed significant binding to human intestinal tissue sections. Our optimized refolding protocol from IBs of this recombinant probiotic FBP led into high amounts of biologically active protein. Our results help in increasing understanding of structure-function relation of surface adhesion proteins and host-microbial interactions.

CK2α promotes advanced glycation end products-induced expressions of fibronectin and intercellular adhesion molecule-1 via activating MRTF-A in glomerular mesangial cells

Advanced glycation end products’ (AGEs) modification of extracellular matrix proteins induces crosslinking, which results in thickening of the basement membrane and activating several intracellular signaling cascades, eventually promoting the pathological progression of diabetic nephropathy (DN). We have previously confirmed that casein kinase 2α (CK2α) activates the nuclear factor of kappaB (NF-κB) signaling pathway to enhance high glucose-induced expressions of fibronectin (FN) and intercellular adhesion molecule-1 (ICAM-1) in glomerular mesangial cells (GMCs). However, to date, the mechanism by which CK2α regulates diabetic renal fibrosis is not fully understood. In view of the regulation of inflammation and fibrosis by myocardin-related transcription factor A (MRTF-A), we are highly concerned whether CK2α promotes AGEs-induced expressions of FN and ICAM-1 in glomerular mesangial cells via activation of MRTF-A, thus affecting the pathogenesis of DN. We found that CK2α and MRTF-A proteins were overexpressed in AGEs-induced diabetic kidneys. Inhibition of CK2α kinase activity or knockdown of CK2α protein expression suppressed the upregulation of FN and ICAM-1 expressions in GMCs induced by AGEs. MRTF-A knockdown compromised the expressions of FN and ICAM-1 in GMCs induced by AGEs. Moreover, inhibition of CK2α kinase activity or knockdown of CK2α protein expression restrained the protein expression and nuclear aggregation of MRTF-A. CK2α interacted with MRTF-A. Furthermore, knockdown of MRTF-A while overexpression of CK2α blocked the upregulation effect of CK2α on the protein expressions of FN and ICAM-1. These findings suggest that CK2α promotes diabetic renal fibrosis via activation of MRTF-A and upregulation of inflammatory genes.

Restructuration kinetics of amphiphilic intraocular lenses during aging

Photooxidation and hydrolysis are the two primary aging factors of intraocular lenses. Opacifications, dislocations, glistening and yellowing of the implanted acrylic lenses, which are due to chain scissions and depolymerization, are the consequences of aging from the clinical perspective. The purpose of this study was to examine the consequence of the aging of intraocular lenses on chemical and surface properties. Acrylic lenses made of poly acrylic-co-polystyrene polymer were artificially aged by photooxidation and hydrolysis from 2 to 20 years. Degradation products were observed by Reverse-phase High-Performance Liquid Chromatography RP-HPLC and thermogravimetric analysis (TGA). The surface, which was analyzed by atomic force microscopy (AFM) and fibronectin adhesion kinetics, was chosen as an indicator of intraocular biocompatibility. Low-molecular-weight degradation products (LMWP) result from chain scission under both hydrolysis and photooxidation. The osmotic effects of water enable degradation products to migrate through the polymer. A portion of the degradation products exudate in the surrounding center, whereas a portion link with lateral chains of the polymer. At the same time, the surface roughness evolves to externalize the most hydrophilic chains. As a result, the fibronectin adhesion level decrease with time, which indicates the existence of a biocompatible kinetic for implanted intraocular lenses.

Sphingosine kinase 1 mediates diabetic renal fibrosis via NF-κB signaling pathway: involvement of CK2α.

Sphingosine kinase 1 (SphK1) plays a pivotal role in regulating diabetic renal fibrotic factors such as fibronectin (FN) and intercellular adhesion molecule-1 (ICAM-1). Especially, activation of SphK1 is closely linked to the body inflammatory reaction. Casein kinase 2α subunit (CK2α), a protein kinase related to inflammatory reaction, influences diabetic renal fibrosis and expressions of FN and ICAM-1 via NF-κB pathway. However, the mechanism by which SphK1 mediates diabetic renal fibrosis has not yet fully elucidated. The current study is aimed to investigate if SphK1 mediates diabetic renal fibrotic pathological process via inflammatory pathway and activation of CK2α. The following findings were observed: (1) Expressions of SphK1 were upregulated in kidneys of diabetic mice and rats; (2) Knockdown of SphK1 expression suppressed high glucose (HG)-induced NF-κB nuclear translocation and expressions of FN and ICAM-1; (3) Compared with C57 diabetic mice, SphK1-/- diabetic mice exhibited less renal fibrotic lesions, FN accumulation and NF-κB nuclear accumulation in glomeruli of kidneys; (4) SphK1 mediated phosphorylation of CK2α, while CK2α knockdown depressed SphK1-induced activation of NF-κB pathway. This study indicates the essential role of SphK1 in regulating activation of CK2α and diabetic renal fibrotic pathological process via NF-κB.

Surface texturing of electrospun fibres by photoembossing using pulsed laser interference holography and its effects on endothelial cell adhesion

Electrospun fibres are nowadays extensively studied for biomedical applications such as tissue engineering and drug delivery. Here, fibres for such applications are electrospun from photopolymer blends using a volatile solvent. The obtained nonwoven fibre mats were textured using a photoembossing technique that uses the interference of two coherent UV laser beams followed by a thermal development step. AFM measurements revealed that the patterned exposure using pulsed laser interference holography resulted in a surface texture on the fibres. The effect of temperature and UV dosage on fibre texturing was studied and was similar to results seen in photoembossed films. Fibronectin and cell adhesion was evaluated on textured fibres of 1 μm diameter with relief structures of 60 nm height and 2 μm pitch. Initial results did not seem to indicate improved cell adhesion for photoembossed fibres compared to their non-embossed counterparts.

Electrospun aniline-tetramer-co-polycaprolactone fibers for conductive, biodegradable scaffolds

Conjugated polymers have been proposed as promising materials for scaffolds in tissue engineering applications. However, the restricted processability and biodegradability of conjugated polymers limit their use for biomedical applications. Here we synthesized a block-co-polymer of aniline tetramer and PCL (AT–PCL), and processed it into fibrous non-woven scaffolds by electrospinning. We showed that fibronectin (Fn) adhesion was dependent on the AT–PCL oxidative state, with a reduced Fn unfolding length on doped membranes. Furthermore, we demonstrated the cytocompatibility and potential of these membranes to support the growth and osteogenic differentiation of MC3T3-E1 cells over 21 days.

Analysing the bioactive makeup of demineralised dentine matrix on bone marrow mesenchymal stem cells for enhanced bone repair.

Dentine matrix has proposed roles for directing mineralised tissue repair in dentine and bone; however, the range of bioactive components in dentine and specific biological effects on bone-derived mesenchymal stem cells (MSCs) in humans are less well understood. The aims of this study were to further elucidate the biological response of MSCs to demineralised dentine matrix (DDM) in enhancing wound repair responses and ascertain key contributing components. Dentine was obtained from human teeth and DDM proteins solubilised with ethylenediaminetetraacetic acid (EDTA). Bone marrow derived MSCs were commercially obtained. Cells with a more immature phenotype were then selected by preferential fibronectin adhesion (FN-BMMSCs) for use in subsequent in vitro assays. DDM at 10 µg/mL reduced cell expansion, attenuated apoptosis and was the minimal concentration capable of inducing osteoblastic differentiation. Enzyme-linked immunosorbent assay (ELISA) quantification of growth factors indicated physiological levels produced the above responses; transforming growth factor β (TGF-β1) was predominant (15.6 ng/mg DDM), with relatively lower concentrations of BMP-2, FGF, VEGF and PDGF (6.2-4.7 ng/mg DDM). Fractionation of growth factors from other DDM components by heparin affinity chromatography diminished osteogenic responses. Depletion of biglycan from DDM also attenuated osteogenic potency, which was partially rescued by the isolated biglycan. Decorin depletion from DDM had no influence on osteogenic potency. Collectively, these results demonstrate the potential of DDM for the delivery of physiological levels of growth factors for bone repair processes, and substantiate a role for biglycan as an additional adjuvant for driving osteogenic pathways.

Fibroblast paracrine TNF-\u03b1 signaling elevates integrin A5 expression in idiopathic pulmonary fibrosis (IPF)

BackgroundIdiopathic pulmonary fibrosis (IPF) is a progressive lung disease with a poor prognosis. Inflammatory cytokines play a significant role in IPF pathology. However, the fibroblast itself is also believed to be the primary effector in IPF. We hypothesized that the fibroblasts themselves secrete pro-inflammatory cytokines that could propagate IPF by affecting normal neighboring cells. Thus, we explored the effects of IPF fibroblast derived media on normal fibroblast characteristics.MethodsPrimary IPF/normal tissue derived fibroblast cultures were established and their supernatants were collected (IPF/N-SN, respectively). These supernatants were added to normal fibroblasts. Cell death (caspase-3, western blot), proliferation, viability (WST-1), migration (scratch test) and cell detachment (crystal violet and fibronectin adhesion assays) were tested. 10 inflammatory cytokines were measured by ELISA-based quantitative array. Integrin α5 (ITGA5), pIκBα, p/total STAT3 levels were measured by western blot/IHC. TNF-α involvement was confirmed using Infliximab ®, anti-TNF-α mAb.ResultsThe IPF-SN facilitated fibroblast cell detachment and reduced cell migration (p < 0.05). Nevertheless, these effects were reversed when cells were seeded on fibronectin. The exposure to the IPF-SN also elevated ITGA5 levels, the fibronectin receptor, in addition to NFκB pathway activation (pIκBα↑ 150%, p < 0.05). In accordance, IPF derived fibroblasts were found to express higher ITGA5 than the normal cells (44%↑, p < 0.05). ITGA5 was also expressed in the fibroblastic foci.The IPF-SN contained high TNF-α levels (3-fold, p < 0.05), and Infliximab pretreatment successfully reversed all the above observations.ConclusionWe suggest a possible mechanism in which IPF fibroblast secreted TNF-α modifies neighboring fibroblast cell behavior.

Polydatin promotes Nrf2-ARE anti-oxidative pathway through activating CKIP-1 to resist HG-induced up-regulation of FN and ICAM-1 in GMCs and diabetic mice kidneys

Our previous study indicated that Casein kinase 2 interacting protein-1 (CKIP-1) could promote the activation of the nuclear factor E2-related factor 2 (Nrf2)/ antioxidant response element (ARE) pathway, playing a significant role in inhibiting the fibrosis of diabetic nephropathy (DN). Polydatin (PD) has been shown to possess strong resistance effects on renal fibrosis which is closely related to activating the Nrf2/ARE pathway, too. Whereas, whether PD could resist DN through regulating CKIP-1 and consequently promoting the activation of Nrf2-ARE pathway needs further investigation. Here, we found that PD significantly reversed the down-regulation of CKIP-1 and attenuated fibronectin (FN) and intercellular cell adhesion molecule-1 (ICAM-1) in glomerular mesangial cells (GMCs) exposed to high glucose (HG). Moreover, PD could decrease Keap1 expression and promote the nuclear content, ARE-binding ability, and transcriptional activity of Nrf2. The activation of Nrf2-ARE pathway by PD eventually led to the quenching of hydrogen peroxide (H2O2) and superoxide overproduction boosted by HG. Depletion of CKIP-1 blocked the Nrf2-ARE pathway activation and reversed FN and ICAM-1 down-regulation induced by PD in GMCs challenged with HG. PD increased CKIP-1 and Nrf2 levels in the kidney tissues as well as improved the anti-oxidative effect and renal dysfunction of diabetic mice, which eventually reversed the up-regulation of FN and ICAM-1. Experiments above suggested that PD could increase the CKIP-1-Nrf2-ARE pathway activation to prevent the OSS-induced insult in GMCs and diabetic mice which effectively postpone the diabetic renal fibrosis and the up-regulation of CKIP-1 is probably a novel mechanism in this process.

PHYSIOLOGICAL FEATURES OF CORYNEBACTERIA OF FEMALE REPRODUCTIVE TRACT

Literature data and results of authors' research on biological properties of corynebacteria of reproductive tract of women are analyzed. General characteristics of microorganisms is given. 20 species of corynebacteria are presented: C. amycolatum, C. aquaticum, C. aurimucosum, C. bovis, C. glucuronolyticum, C. coyleae, C.freneyi, C.jeikeium var. genitalium, C.jeikeium var. pseudogeni- talium, C. lipophiloflavum, C. kutscheri, C. minutissimum, C. nigricans, C. pseudodiphtheriticum, C. pseudotuberculosis, C. renale, C. striatum, C. tuberculostearicum (lipophile) (includes most CDC group G-2 strains), C. xerosis and C. urealyticum. Mechanisms and factors ensuring the ability of corynebacteria to exist in vaginal biotope regardless of microecological condition- the presence of high resistance to factors of innate immunity (lysozyme, complement, immunoglobulins), pH- dependent adhesion to fibronectin and vaginal epitheliocytes - are examined. The role of fi- bronectin in adhesion of bacteria to vaginal epithelial cells is described. Corynebacteria exome- tabolites are shown to facilitate maximal realization of antagonistic activity of vaginal peroxide-producing lactobacilliby supressing catalase ofopportunistic microorganisms-symbionts, that directly influences the quantity and structure of bacterial population by suppressing growth and biofilm-formation. The materials provided give evidence on the significant role of corynebac- teria in realization of physiological phenomenon - colonization resistance and allow us to exam- ine these microorganisms as an integral part of normal microbiota of woman reproduction tract.

CKIP-1 ameliorates high glucose-induced expression of fibronectin and intercellular cell adhesion molecule-1 by activating the Nrf2/ARE pathway in glomerular mesangial cells

Glucose and lipid metabolism disorders as well as oxidative stress (OSS) play important roles in diabetic nephropathy (DN). Glucose and lipid metabolic dysfunctions are the basic pathological changes of chronic microvascular complications of diabetes mellitus, such as DN. OSS can lead to the accumulation of extracellular matrix and inflammatory factors which will accelerate the progress of DN. Casein kinase 2 interacting protein-1 (CKIP-1) mediates adipogenesis, cell proliferation and inflammation under many circumstances. However, whether CKIP-1 is involved in the development of DN remains unknown. Here, we show that CKIP-1 is a novel regulator of resisting the development of DN and the underlying molecular mechanism is related to activating the nuclear factor E2-related factor 2 (Nrf2)/antioxidant response element (ARE) antioxidative stress pathway. The following findings were obtained: (1) The treatment of glomerular mesangial cells (GMCs) with high glucose (HG) decreased CKIP-1 levels in a time-dependent manner; (2) CKIP-1 overexpression dramatically reduced fibronectin (FN) and intercellular adhesionmolecule-1 (ICAM-1) expression. Depletion of CKIP-1 further induced the production of FN and ICAM-1; (3) CKIP-1 promoted the nuclear accumulation, DNA binding, and transcriptional activity of Nrf2. Moreover, CKIP-1 upregulated the expression of Nrf2 downstream genes, heme oxygenase (HO-1) and superoxide dismutase 1 (SOD1); and ultimately decreased the levels of reactive oxygen species (ROS). The molecular mechanisms clarify that the advantageous effect of CKIP-1 on DN are well connected with the activation of the Nrf2/ARE antioxidative stress pathway.

Nuclear factor kappa-B- and activator protein-1-mediated immunostimulatory activity of compound K in monocytes and macrophages

BackgroundCompound K (CK) is a bioactive derivative of ginsenoside Rb1 in Panax ginseng (Korean ginseng). Its biological and pharmacological activities have been studied in various disease conditions, although its immunomodulatory role in innate immunity mediated by monocytes/macrophages has been poorly understood. In this study, we aimed to elucidate the regulatory role of CK on cellular events mediated by monocytes and macrophages in innate immune responses. MethodsThe immunomodulatory role of CK was explored by various immunoassays including cell-cell adhesion, fibronectin adhesion, cell migration, phagocytic uptake, costimulatory molecules, reactive oxygen species production, luciferase activity, and by the measurement of mRNA levels of proinflammatory genes. ResultsCompound K induced cell cluster formation through cell-cell adhesion, cell migration, and phagocytic activity, but it suppressed cell-tissue interactions in U937 and RAW264.7 cells. Compound K also upregulated the surface expression of the cell adhesion molecule cluster of differentiation (CD) 43 (CD43) and costimulatory molecules CD69, CD80, and CD86, but it downregulated the expression of monocyte differentiation marker CD82 in RAW264.7 cells. Moreover, CK induced the release of reactive oxygen species and induced messenger RNA expression of proinflammatory genes, inducible nitric oxide synthase, and tumor necrosis factor-alpha by enhancing the nuclear translocation and transcriptional activities of nuclear factor kappa-B and activator protein-1. ConclusionOur results suggest that CK has an immunomodulatory role in innate immune responses through regulating various cellular events mediated by monocytes and macrophages.

Aliskiren directly improves endothelial progenitor cell function from Type II diabetic patients.

Endothelial progenitor cell (EPC) functions are impaired in the presence of diabetes mellitus. Aliskiren is a direct renin inhibitor, which is expected to modify proangiogenic cells. This study aimed to investigate whether and how aliskiren could improve the function of EPCs from patients with type II diabetes (T2DM). Endothelial progenitor cells fibronectin adhesion assay, chamber assay and in vitro tube formation assay were used to estimate the degree of EPC adhesion, migration and tube formation abilities. EPC protein and mRNA expressions were evaluated by Western blot and quantitative RT-PCR, respectively. EPC vascular endothelial growth factor (VEGF) and (pro)renin receptor ((P)RR) expression was knocked down by VEGF and (P)RR siRNA. Aliskiren (0·1 or 10 μM) dose-dependently improved functions and increased both VEGF and stromal cell-derived factor-1α (SDF-1α) expression of EPCs from patients with T2DM or EPCs from healthy volunteers and treated with high glucose. Transfection with VEGF siRNA significantly reduced the aliskiren-induced SDF-1α expression. Furthermore, (P)RR siRNA transfection impaired the aliskiren-induced VEGF and SDF-1 expression. The results show that aliskiren improved EPC function from patients with T2DM in a dose-dependent manner probably via the (P)RR and VEGF/SDF-1α-related mechanisms.

Heparanase-induced shedding of syndecan-1/CD138 in myeloma and endothelial cells activates VEGFR2 and an invasive phenotype: prevention by novel synstatins.

Multiple myeloma arises when malignant plasma cells invade and form multiple tumors in the bone marrow. High levels of heparanase (HPSE) correlate with poor prognosis in myeloma patients. A likely target of the enzyme is the heparan sulfate (HS) proteoglycan syndecan-1 (Sdc1, CD138), which is highly expressed on myeloma cells and contributes to poor prognosis in this disease. We find that HPSE promotes an invasive phenotype mediated by the very late antigen-4 (VLA-4, or α4β1 integrin) in myeloma cells plated on either fibronectin (FN) or vascular endothelial cell adhesion molecule-1 (VCAM-1), ligands that are prevalent in the bone marrow. The phenotype depends on vascular endothelial cell growth factor receptor-2 (VEGFR2), which is aberrantly expressed in myeloma, and is characterized by a highly protrusive lamellipodium and cell invasion. HPSE-mediated trimming of the HS on Sdc1 and subsequent matrix metalloproteinase-9-mediated shedding of the syndecan exposes a juxtamembrane site in Sdc1 that binds VEGFR2 and VLA-4, thereby coupling VEGFR2 to the integrin. Shed Sdc1 can be mimicked by recombinant Sdc1 ectodomain or by a peptide based on its binding motif, which causes VLA-4 to re-orient from the lagging edge (uropod) to the leading edge of migrating cells, couple with and activate VEGFR2. Peptides (called 'synstatins') containing only the VLA-4 or VEGFR2 binding sites competitively inhibit invasion, as they block coupling of the receptors. This mechanism is also utilized by vascular endothelial cells, in which it is also activated by HPSE, during endothelial cell tube formation. Collectively, our findings reveal for the first time the mechanism through which HPSE modulates Sdc1 function to promote both tumor cell invasion and angiogenesis, thereby driving multiple myeloma progression. The inhibitory synstatins, or inhibitors of HPSE enzyme activity, are likely to show promise as therapeutics against myeloma extravasation and spread.

Kindlin-2 cooperates with talin to activate integrins and induces cell spreading by directly binding paxillin.

Integrins require an activation step prior to ligand binding and signaling. How talin and kindlin contribute to these events in non-hematopoietic cells is poorly understood. Here we report that fibroblasts lacking either talin or kindlin failed to activate β1 integrins, adhere to fibronectin (FN) or maintain their integrins in a high affinity conformation induced by Mn(2+). Despite compromised integrin activation and adhesion, Mn(2+) enabled talin- but not kindlin-deficient cells to initiate spreading on FN. This isotropic spreading was induced by the ability of kindlin to directly bind paxillin, which in turn bound focal adhesion kinase (FAK) resulting in FAK activation and the formation of lamellipodia. Our findings show that talin and kindlin cooperatively activate integrins leading to FN binding and adhesion, and that kindlin subsequently assembles an essential signaling node at newly formed adhesion sites in a talin-independent manner.