Development of vascular smooth muscle contractility by endothelium-derived transforming growth factor β proteins.

It is well established that the release of vasodilators and vasoconstrictors from vascular endothelium regulates vascular smooth muscle contraction. In this report, we investigate the role of the endothelium in the development and maintenance of constitutive vascular contractility. For that purpose, contractile activity of cultured bovine aortic smooth muscle cells (BASMCs) embedded in collagen gels was monitored by changes in gel diameter.

Endothelium-dependent epithelial-mesenchymal transition of tumor cells: exclusive roles of transforming growth factor β1 and β2.

Background: Induction of epithelial-mesenchymal transition (EMT) is essential for the metastasis of tumor cells and maintaining their stemness. This study aimed to examine whether endothelial cells, which are most closely located to tumor cells in vivo, play a role in inducing EMT in tumor cells or not.

Methods: Concentrated culture medium of bovine aortic endothelial cells (BAECs) was applied to tumor cell lines (A549 and PANC-1) and epithelial cell line (NMuMg).

Leukotriene B4 receptor BLT2 negatively regulates allergic airway eosinophilia.

Leukotriene B4 (LTB4) has been implicated in the pathogenesis of allergic diseases. BLT2, a low-affinity LTB4 receptor, is activated by LTB4 and 12(S)-hydroxyheptadeca-5Z,8E,10E-trienoic acid (12-HHT). Although the high-affinity LTB4 receptor BLT1 has been shown to exert proinflammatory roles, the role of BLT2 in allergic inflammation has not been clarified.

Transforming growth factor beta1 alters calcium mobilizing properties and endogenous ATP release in A549 cells: possible implications for cell migration.

We examined the effects of transforming growth factor beta(1) (TGFbeta(1)) on cellular functions in human lung cancer cell line A549. Treatment of A549 cells with 1 ng/ml TGFbeta(1) for more than 3 days altered their morphology from an epithelial cobblestone-like appearance to a fibroblast-like one, reduced the expression of E-cadherin mRNA and protein, and induced the formation of F-actin fibers. These hallmarks indicate that TGFbeta(1) induced the epithelial-mesenchymal transition in A549 cells.

Heparan sulfate proteoglycan is essential to thrombin-induced calcium transients and nitric oxide production in aortic endothelial cells.

Thrombin induces Ca(2+) transients and subsequent nitric oxide (NO) production in vascular endothelial cells. Thrombin cleaves protease-activated receptors, resulting in activation of intracellular signals, but it is not clarified how the extracellular thrombin stays around the cells to exert its enzyme activities. This study aimed to investigate the possible involvement of heparin sulfate proteoglycan (HSPG) in the effects of thrombin on vascular endothelium.

The role of L- and T-type calcium channels in local and remote calcium responses in rat mesenteric terminal arterioles.

Background/aims: The roles of intercellular communication and T-type versus L-type voltage-dependent Ca(2+) channels (VDCCs) in conducted vasoconstriction to local KCl-induced depolarization were investigated in mesenteric arterioles.

Methods: Ratiometric Ca(2+) imaging (R) using Fura-PE3 with micro-ejection of depolarizing KCl solution and VDCC blockers, and immunohistochemical and RT-PCR techniques were applied to isolated rat mesenteric terminal arterioles (n = 71 from 47 rats; intraluminal diameter: 24 +/- 1 microm; length: 550-700 microm).

Results: Local application of KCl (at 0 microm) led to local (DeltaR = 0.

Involvement of heparan sulfate proteoglycan in sensing hypotonic stress in bovine aortic endothelial cells.

Hypotonic stress (HTS) induces various responses in vascular endothelium, but the molecules involved in sensing HTS are not known. To investigate a possible role of heparan sulfate proteoglycan (HSPG) in sensing HTS, we compared the responses of control bovine aortic endothelial cells (BAECs) with those of cells treated with heparinase III, which exclusively degrades HSPG. Tyrosine phosphorylation of 125 kDa FAK induced by HTS (-30%) in control cells was abolished in heparinase III-treated BAECs.

Hypergravity induces ATP release and actin reorganization via tyrosine phosphorylation and RhoA activation in bovine endothelial cells.

Mechanical stresses regulate physiological and pathological functions of vascular endothelial cells. We examined, in this study, the effects of hypergravity on endothelial functions. Hypergravity (3 G) applied by low speed centrifuge immediately induced a membrane translocation of small G-protein RhoA and tyrosine phosphorylation of 125 kDa FAK in bovine aortic endothelial cells (BAECs).

Dual modulation of airway smooth muscle contraction by Th2 cytokines via matrix metalloproteinase-1 production.

Altered contractility of airway smooth muscle (SM) is one of the main causes of allergic asthma, in which the predominance of Th2 over Th1 cytokines plays a central role. In the present study, we examine the effects of Th2 cytokines on airway SM contraction. Treatment with a low concentration of IL-4 (0.

Proapoptotic nitric oxide production in amyloid beta protein-treated cerebral microvascular endothelial cells.

Objective: The objective of this study was to investigate the effects of amyloid beta protein (Abeta) on cerebral microvascular endothelium, and their possible involvement in Abeta-induced apoptosis in the neighboring cells.

Methods: Cultured bovine brain microvascular endothelial cells (BBECs) were incubated with Abeta for 24 h. Production of nitric oxide (NO) was assessed by nitric oxide-sensitive fluorescent dye, DAF-2, and the expression of NO synthase (NOS) proteins was examined by Western blotting.

Protein kinase A inhibits lysophosphatidic acid-induced migration of airway smooth muscle cells.

Lysophosphatidic acid (LPA) is a bioactive phospholipid that is released from activated platelets and affects contractile properties of airway smooth muscle cells. However, possible roles of LPA on cell migration, one of the initial events of airway remodeling, are not clarified. This study aimed to examine the effects of LPA on migration and actin fiber formation in bovine tracheal smooth muscle cells (BTSMCs).

Pivotal role of integrin alpha5beta1 in hypotonic stress-induced responses of human endothelium.

We have previously reported that both hypotonic stress (HTS) and lysophosphatidic acid (LPA) induce ATP release and a transient reorganization of actin through sequential activation of RhoA/Rho-kinase and focal adhesion kinase F-actin (FAK)/paxillin in human umbilical cord vein endothelial cells (HUVECs). LPA is known to induce the activation of RhoA via its specific receptors, but the mechanisms by which HTS initiates these intracellular signals are not known. The present study aimed to identify the molecule(s) that are unique to the sensing and/or transducing the mechanical stress.

Excess l-arginine restores endothelium-dependent relaxation impaired by monocrotaline pyrrole.

The pyrrolizidine alkaloid plant toxin monocrotaline pyrrole (MCTP) causes pulmonary hypertension in experimental animals. The present study aimed to examine the effects of MCTP on the endothelium-dependent relaxation. We constructed an in vitro disease model of pulmonary hypertension by overlaying MCTP-treated bovine pulmonary artery endothelial cells (CPAEs) onto pulmonary artery smooth muscle cell-embedded collagen gel lattice.

Role of PRIP-1, a novel Ins(1,4,5)P3 binding protein, in Ins(1,4,5)P3-mediated Ca2+ signaling.

PRIP-1 was isolated as a novel inositol 1,4,5-trisphosphate [Ins(1,4,5)P3] binding protein with a domain organization similar to phospholipase C-delta1 (PLC-delta1) but lacking the enzymatic activity. Further studies revealed that the pleckstrin homology (PH) domain of PRIP-1 is the region responsible for binding Ins(1,4,5)P3. In this study we aimed to clarify the role of PRIP-1 at the physiological concentration in Ins(1,4,5)P3-mediated Ca2+ signaling, as we had previously used COS-1 cells overexpressing PRIP-1 (Takeuchi et al.

[ATP release pathways in vascular endothelial cells].

Vascular endothelial cells regulate vascular tonus, growth, and angiogenesis in response to mechanical stresses. ATP release is one of well-known mechanosensitive responses in endothelial cells. Released ATP induces Ca(2+) responses and nitric oxide production in neighboring cells in an auto/paracrine manner.

Sequential activation of RhoA and FAK/paxillin leads to ATP release and actin reorganization in human endothelium.

We have investigated the cellular mechanisms of mechanical stress-induced immediate responses in human umbilical vein endothelial cells (HUVECs). Hypotonic stress (HTS) induced ATP release, which evoked a Ca(2+) transient, followed by actin reorganization within a few minutes, in HUVECs. Disruption of the actin cytoskeleton did not suppress HTS-induced ATP release, and inhibition of the ATP-mediated Ca(2+) response did not affect actin reorganization, thereby indicating that these two responses are not interrelated.

[Analysis of airway hyperresponsiveness using in vitro contraction model].

We have established an in vitro model of airway hyperresponsiveness, using bovine tracheal smooth muscle cells (BTSMC)-embedded collagen gel lattice. When the gel was pretreated with lysophosphatidic acid (LPA), which activates small G-protein RhoA, ATP- and high K+ solution-induced gel contraction was significantly augmented. This was not due to the modulation of Ca(2+)-mobilizing properties, since ATP- and high K(+)-induced Ca2+ transients were not different significantly between control and LPA-treated BTSMC.

Constitutive nitric oxide production in bovine aortic and brain microvascular endothelial cells: a comparative study.

Vascular endothelium constitutively generates nitric oxide (NO) in large vessels and induces a relaxation of smooth muscle cells. However, little is known about the production of NO in microvessels, where smooth muscle layers are thin or absent. In this study, we have compared the constitutive production of NO in bovine brain microvascular endothelial cells (BBECs) with that in bovine aortic endothelial cells (BAECs).

Calcium-dependent injury of human microvascular endothelial cells induced by a variety of iodinated radiographic contrast media.

Rationale And Objectives: The aim of the present study was to determine the possible mechanisms underlying the endothelial cell damage induced by iodinated radiographic contrast materials (RCM).

Methods: The cultured human skin microvascular endothelial cells (HMVECs) were exposed to various contrast media, and the cell viability was measured by mitochondrial enzyme activity. Nuclear damage was assessed by Hoechst 33342 staining and a fluorescent single-cell gel electrophoresis.

DOCK2 is essential for antigen-induced translocation of TCR and lipid rafts, but not PKC-theta and LFA-1, in T cells.

DOCK2 is a mammalian homolog of Caenorhabditis elegans CED-5 and Drosophila melanogaster Myoblast City which are known to regulate actin cytoskeleton. DOCK2 is critical for lymphocyte migration, yet the role of DOCK2 in TCR signaling remains unclear. We show here that DOCK2 is essential for TCR-mediated Rac activation and immunological synapse formation.

Involvement of proteinase-activated receptor-2 in mast cell tryptase-induced barrier dysfunction in bovine aortic endothelial cells.

We report here a direct modulation by mast cell tryptase of endothelial barrier function through activation of proteinase-activated receptor-2 (PAR-2). In cultured bovine aortic endothelial cells (BAECs), tryptase, trypsin and PAR-2 activating peptide impaired the barrier function as determined by the permeability of protein-conjugated Evans blue. The tryptase-induced barrier dysfunction was completely blocked by U73122, and partially reversed by xestospongin C, calphostin C or Y27632.

Theophylline and cAMP inhibit lysophosphatidic acid-induced hyperresponsiveness of bovine tracheal smooth muscle cells.

We have established an in vitro model of airway hyperresponsiveness, using a bovine tracheal smooth muscle cell (BTSMC)-embedded collagen gel lattice. When the gel was pretreated with lysophosphatidic acid (LPA), which activates the small G protein RhoA, ATP- and high K+ solution-induced gel contraction was significantly augmented. This was not due to the modulation of Ca2+ mobilizing properties, since ATP- and high K+-induced Ca2+ transients were not significantly different between control and LPA-treated BTSMC.

[Regulatory role of mechanical stress response in cellular function: development of new drugs and tissue engineering].

The investigation of mechanotransduction in the cardiovascular system is essentially important for elucidating the cellular and molecular mechanisms involved in not only the maintenance of hemodynamic homeostasis but also etiology of cardiovascular diseases including arteriosclerosis. The present review summarizes the latest research performed by six academic groups, and presented at the 75th Annual Meeting of the Japanese Pharmacological Society. Technology of cellular biomechanics is also required for research and clinical application of a vascular hybrid tissue responding to pulsatile stress.

Functional implications of Ca2+ mobilizing properties for nitric oxide production in aortic endothelium.

We have investigated the relationship between Ca2+ mobilization and the cellular production of nitric oxide (NO) by using fura-2 and diaminofluorescein-2 (DAF-2), an NO-sensitive dye, in bovine aortic endothelial cells (BAEC). High concentrations of ATP (100 microM) or thapsigargin (1 micro M) depleted intracellular Ca2+ store sites with a single Ca2+ transient, and induced an increase in DAF-2 fluorescence even in Ca2+-free solution, thereby indicating that store depletion leads to NO production. The same level of increase in DAF-2 fluorescence was elicited by low concentrations of ATP (1 micro M), which induced Ca2+ oscillations but did not deplete store sites, only in the presence of extracellular Ca2+.