Search PubMed⌕ Search

SEARCH · Search PubMed

Results for “ADHESIONS”

Search indexed PubMed citations on genomics, clinical trials, systematic reviews and public health. Explore titles, authors and supplied subject terms, then open the PubMed record.

Quote a phrase for an exact phrase match. Source license links do not imply unrestricted reuse.

At least 595 records · Page 33Linked to original sources

Differential activation of ERKs to focal adhesions by PKC epsilon is required for PMA-induced adhesion and migration of human glioma cells.

Protein kinase C (PKC) is a family of serine/threonine kinases involved in the transduction of a variety of signals. There is increasing evidence to indicate that specific PKC isoforms are involved in the regulation of distinct cellular processes. In glioma cells, PKC alpha was found to be a critical regulator of proliferation and cell cycle progression, while PKC epsilon was found to regulate adhesion and migration. Herein, we report that specific PKC isoforms are able to differentially activate extracellular-signal regulated kinase (ERK) in distinct cellular locations: while PKC alpha induces the activation of nuclear ERK, PKC epsilon induces the activation of ERK at focal adhesions. Inhibition of the ERK pathway completely abolished the PKC-induced integrin-mediated adhesion and migration. Thus, we present the first evidence that PKC epsilon is able to activate ERK at focal adhesions to mediate glioma cell adhesion and motility, providing a molecular mechanism to explain the different biological functions of PKC alpha and epsilon in glioma cells.

Androstadienes↗

Adhesion of T lymphoblasts to epidermal keratinocytes is regulated by interferon gamma and is mediated by intercellular adhesion molecule 1 (ICAM-1).

The cell surface expression and function of the LFA-1 ligand, intercellular adhesion molecule 1 (ICAM-1), on epidermal keratinocytes (EK) was studied. ICAM-1 expression on the surface of cultured EK was either absent or weak, but was induced by treating EK with rIFN-gamma or TNF for 4-48 h. IFN-gamma and TNF were synergistic. IFN-gamma treatment increased T lymphoblast adhesion from less than 2% to 20-40%, with a concentration dependence similar to that seen for ICAM-1 induction. All of the adhesion to EK was inhibited by LFA-1 and ICAM-1 mAbs, but not by HLA-DR, CD2, or LFA-3 mAbs. There was no difference in the level of T lymphoblast adhesion to IFN-gamma-treated allogeneic or autologous EK. ICAM-1 purified from the HeLa epithelioid cell line and reconstituted into planar membranes also supported efficient adhesion of T lymphoblasts that was blocked by LFA-1 mAb bound to the T lymphoblasts or ICAM-1 mAb bound to the planar membranes. T lymphoblasts adherent to EK or ICAM-1 planar membranes were isolated by panning, and surface markers were analyzed by immunofluorescence flow cytometry. The adherent T cells were a phenotypically skewed subpopulation. They were enriched for CD8+ cells and expressed 1.5-2.5-fold higher LFA-1 and CD2 compared with the unseparated population.

Antibodies, Monoclonal↗

Adhesion mediated by intercellular adhesion molecule 1 attenuates the potency of antibodies that block HIV-1 gp160-dependent syncytium formation.

Several lines of evidence suggest that leukocyte adhesion molecules can promote HIV-1-mediated cell fusion and syncytium formation. In the present studies, the human kidney cell line, 293, was transfected with the envelope glycoprotein gene of the MN strain of HIV-1 alone or cotransfected with a cDNA encoding intercellular adhesion molecule 1 (ICAM-1). It was found that 293 cells transfected with the HIV-1MN env gene expressed the HIV-1 polyglycoprotein precursor, gp160, and the mature gp120-gp41 complex. When mixed with a CD4+ T cell line (CEM), the gp160-transfected cells mediated heterotypic cell fusion and formed multinucleate syncytia. Virus-neutralizing monoclonal antibodies to the V2 and V3 domains of gp120 were able to inhibit syncytium formation, as were monoclonal antibodies to CD4. When ICAM-1 was coexpressed with gp160, syncytium formation between the transfected kidney cells and uninfected CD$+ T cells was markedly enhanced. Inhibitors of HIV-1 infectivity (e.g., monoclonal antibodies to gp120, recombinant soluble CD4) were able to prevent syncytium formation; however, the syncytium-blocking activity of these agents was significantly attenuated in cultures in which ICAM-1 was cotransfected with gp160. These results confirm that leukocyte adhesion molecules can promote gp160-mediated syncytium formation and demonstrate, for the first time, that adhesive interactions mediated by ICAM-1 and its contrareceptor, LFA-1, attenuate the syncytium-inhibiting activity of virus-neutralizing monoclonal antibodies and soluble CD4. These findings suggest that the type and magnitude of leukocyte adhesion molecules expressed on cells may be a significant variable in in vitro HIV-1 neutralization assays.

Binding, Competitive↗

Defining extracellular integrin alpha-chain sites that affect cell adhesion and adhesion strengthening without altering soluble ligand binding.

It was previously shown that mutations of integrin alpha4 chain sites, within putative EF-hand-type divalent cation-binding domains, each caused a marked reduction in alpha4beta1-dependent cell adhesion. Some reports have suggested that alpha-chain "EF-hand" sites may interact directly with ligands. However, we show here that mutations of three different alpha4 "EF-hand" sites each had no effect on binding of soluble monovalent or bivalent vascular cell adhesion molecule 1 whether measured indirectly or directly. Furthermore, these mutations had minimal effect on alpha4beta1-dependent cell tethering to vascular cell adhesion molecule 1 under shear. However, EF-hand mutants did show severe impairments in cellular resistance to detachment under shear flow. Thus, mutation of integrin alpha4 "EF-hand-like" sites may impair 1) static cell adhesion and 2) adhesion strengthening under shear flow by a mechanism that does not involve alterations of initial ligand binding.

Amino Acid Sequence↗

Cytokine-induced modulation of cellular adhesion to human cerebral endothelial cells is mediated by soluble vascular cell adhesion molecule-1.

Tumour necrosis factor-alpha ( TNF-alpha) has been proposed as one of the key mediators of inflammatory diseases of the CNS such as multiple sclerosis. It has been shown to induce the expression of adhesion molecules which is a prerequisite for the transmigration of immune cells through the blood-brain barrier. We therefore investigated the role of TNF-alpha in the expression and release of vascular cell adhesion molecule-1 (VCAM-1) in cultures of human cerebral endothelial cells (HCEC) in comparison with peripheral blood mononuclear cells (PBMC). A time- and dose-dependent expression of VCAM-1 and release of soluble VCAM-1 was detected in HCEC but not PBMC. TNF-alpha-induced release of soluble VCAM-1 was further increased by cotreatment with interferon-beta (IFN-beta), while IFN-beta alone did not affect VCAM-1 expression or the release of soluble VCAM-1. In addition, we observed that preincubation of PBMC with soluble VCAM-1 completely blocked their adhesion to HCEC. In conclusion, the proinflammatory effect of TNF-alpha on HCEC, which involves the induction of VCAM-1 expression and cellular adhesion, is followed by the consecutive effects of soluble VCAM-1 release in blocking adhesion and downregulating further cellular infiltration. Increasing soluble VCAM-1 release during active inflammation could be another mechanism by which IFN-beta treatment exerts protective effects in multiple sclerosis patients.

Antibodies, Monoclonal↗

The anti-inflammatory peptides, antiflammins, regulate the expression of adhesion molecules on human leukocytes and prevent neutrophil adhesion to endothelial cells.

Antiflammin-1 and antiflammin-2 are nonapeptides corresponding to the region of highest similarity between glucocorticoid-inducible proteins lipocortin-1 and uteroglobin. We have studied whether antiflammins could affect expression of adhesion molecules on human leukocytes and coronary artery endothelial cells (HCAEC) and binding of neutrophils (PMNs) to HCAEC. Although neither antiflammin-1 nor antiflammin-2 affected expression of adhesion molecules on resting PMNs, monocytes, and lymphocytes in whole blood, they attenuated changes in L-selectin and CD11/CD18 expression evoked by platelet-activating factor or interleukin-8 with IC(50) values of 4-20 micromol/l. The maximum inhibition was similar to those seen with human recombinant lipocortin-1 (100 microgram/ml). Unlike dexamethasone (100 nmol/l), the antiflammins had little effect on LPS-stimulated expression of E-selectin and ICAM-1 on HCAEC. Consistently, culture of HCAEC with dexamethasone, but not with antiflammins, decreased PMN binding to endothelial cells. Preincubation of PMNs with antiflammins markedly decreased their adhesion to LPS-activated HCAEC. Inhibition of adhesion was additive with function blocking anti-E-selectin and anti-L-selectin antibodies, but was not additive with anti-CD18 antibody. These results show that antiflammins inhibit PMN adhesion to HCAEC by attenuating activation-induced up-regulation of CD11/CD18 expression on leukocytes, and suggest that antiflammins may represent a novel therapeutic approach in blocking leukocyte trafficking in host defense and inflammation.

Adult↗

Effects of severe, uncontrolled hypertension on endothelial activation: soluble vascular cell adhesion molecule-1, soluble intercellular adhesion molecule-1 and von Willebrand factor.

OBJECTIVES: The molecular mechanisms whereby severe, uncontrolled hypertension (SHT) is translated into acute vascular target organ dysfunction have not been completely defined. We sought to determine whether SHT is associated with pressure-dependent endothelial activation as assessed by soluble vascular cell adhesion molecule-1 (sVCAM-1), soluble intercellular adhesion molecule-1 (sICAM-1) and von Willebrand Factor (vWF). METHODS: We determined sVCAM-1, sICAM-1 and vWF in three groups: (i) untreated patients referred specifically for treatment of SHT [diastolic blood pressure (DBP) > or = 120 mm Hg; n = 24]; (ii) untreated patients with established mild hypertension (MHT; DBP 95-100 mmHg; n = 19); and (iii) normotensive volunteers (DBP < or = 90; n = 16). RESULTS: By analysis of variance, sVCAM-1 (P = 0.002), sICAM-1 (P = 0.02) and vWF (P = 0.009) were greater in SHT and MHT than in normotensives but did not differ between SHT and MHT. We observed a significant positive correlation between blood pressure and soluble activation markers at lower blood pressures (normotensives and MHT considered together) that was not present in SHT. CONCLUSIONS: Even mild elevation of blood pressure may be sufficient to activate the expression of adhesion molecules. Mechanisms other than the endothelial expression of adhesion molecules may be important in mediating the accelerated target organ injury produced by SHT in humans. Concentrations of soluble adhesion molecules and vWF may depend more strongly upon factors in the hypertensive microenvironment other than the absolute level of blood pressure.

Adult↗

Structural features of the focal adhesion kinase-paxillin complex give insight into the dynamics of focal adhesion assembly.

The C-terminal region of focal adhesion kinase (FAK) consists of a right-turn, elongated, four-helix bundle termed the focal adhesion targeting (FAT) domain. The structure of this domain is maintained by hydrophobic interactions, and this domain is also the proposed binding site for the focal adhesion protein paxillin. Paxillin contains five well-conserved LD motifs, which have been implicated in the binding of many focal adhesion proteins. In this study we determined that LD4 binds specifically to only a single site between the H2 and H3 helices of the FAT domain and that the C-terminal end of LD4 is oriented toward the H2-H3 loop. Comparisons of chemical-shift perturbations in NMR spectra of the FAT domain in complex with the binding region of paxillin and the FAT domain bound to both the LD2 and LD4 motifs allowed us to construct a model of FAK-paxillin binding and suggest a possible mechanism of focal adhesion disassembly.

Amino Acid Motifs↗

Rapid adhesive responses of endothelial cells and of neutrophils induced by leukotriene B4 are mediated by leucocytic adhesion protein CD18.

Controversy has existed as to the ability of leukotriene B4 (LTB4) to enhance adhesive properties of human neutrophils (PMN) and endothelial cells. We found that LTB4 induced a rapid but transient adhesion of PMN to an albumin-coated plastic surface and to cultured human umbilical vein endothelial cells (HUVEC). Although the adhesive response of PMN to the chemotactic peptide N-formyl-methionyl-leucyl-phenylalanine (fMLP) was longer lasting, peak hyperadherence was of similar magnitude as to LTB4 and was less susceptible to assay conditions. Adherence induced by either LTB4 or fMLP could be abrogated by the monoclonal antibody 60.3, indicating similar dependence on the leucocyte adhesion protein CD18. Lipoxin A did not induce PMN hyperadherence. Treating HUVEC with LTB4, but not with its omega-oxidized metabolites 20-OH- and 20-COOH-LTB4, lipoxin A, or with fMLP conferred a rapid, dose-related, enhanced adhesion of PMN. This effect was dependent on CD18 and on divalent cations. It disappeared with prolonged exposure to LTB4, required a metabolically active HUVEC, and was not due to passive binding of LTB4 to HUVEC. Thus, LTB4 induces a transient expression of hyperadhesiveness in HUVEC as well as in neutrophils, and both effects are dependent on expression of CD18.

Antibodies, Monoclonal↗

Differential binding of clonal variants of Plasmodium falciparum to allelic forms of intracellular adhesion molecule 1 determined by flow adhesion assay.

Adhesion of Plasmodium falciparum-infected erythrocytes to the endothelial ligand intercellular adhesion molecule 1 (ICAM-1) has been implicated in the pathogenesis of cerebral malaria. Recently, a high-frequency coding polymorphism in the N-terminal domain of ICAM-1 (ICAM-1(Kilifi)) that is associated with susceptibility to cerebral disease in Kenya has been described. Preliminary static adhesion assays suggested that two different selected P. falciparum lines, ITO4-A4 (A4) and ItG-ICAM (ItG), have different properties of binding to the natural variant proteins ICAM-1 and ICAM-1(Kilifi). Using a flow adhesion assay system, we have confirmed differences between the two lines in binding of parasitized erythrocytes to the variant ICAM-1 proteins. Total adhesion of ItG-infected erythrocytes to ICAM-1 and ICAM-1(Kilifi) is greater than that of A4-infected erythrocytes, and erythrocytes infected by both parasite strains show reduced binding to ICAM-1(Kilifi). However, under these physiologically relevant flow conditions, we have shown differences between A4 and ItG strains in dynamic rolling behavior on ICAM-1(Kilifi). The percentage of erythrocytes infected with A4 that roll on both ICAM-1 and ICAM-1(Kilifi) is greater than that of those infected with ItG. Also, the rolling velocity of A4-infected erythrocytes on ICAM-1(Kilifi) is markedly increased compared to that on ICAM-1, in contrast to the rolling velocity of ItG-infected erythrocytes, which is similar on both proteins. These findings suggest that different parasite lines can vary in their avidity for the same host ligand, which may have important consequences for the pathophysiology of P. falciparum malaria.

Alleles↗

Intercellular adhesion molecule 1 is important for the development of severe experimental malaria but is not required for leukocyte adhesion in the brain.

Plasmodium berghei-infected mice, a well-recognized model of experimental cerebral malaria (ECM), exhibit a systemic inflammatory response. Most investigators hypothesize that leukocytes bind to endothelial cells via intercellular adhesion molecule 1 (ICAM-1), which causes endothelial damage, increased microvascular permeability, and, ultimately, death. ICAM-1-deficient mice on an ECM-susceptible C57BL/6 background were significantly (p = .04) protected from P. berghei mortality compared with ICAM-1 intact controls. ICAM-1 expression assessed by the dual radiolabeled monoclonal antibody technique was increased in the brain and lung in C57BL/6 mice on day 6 of P. berghei infection compared with uninfected controls (5.3-fold, p = .0003 for brain and 1.8-fold, p = .04 for lung). The increase in ICAM-1 expression coincided with significant (p < .05) increases in microvascular permeability in the brain and lung. In contrast to the hypothesized role for ICAM-1, in vivo analysis by intravital microscopy of leukocyte rolling and adhesion in brain microvasculature of mice revealed markedly increased levels of leukocyte rolling and adhesion in ICAM-1-deficient mice on day 6 of P. berghei infection compared with uninfected controls. In addition, ICAM-1 expression and microvascular permeability were increased in infected ECM-resistant BALB/c mice compared with uninfected BALB/c controls. These results collectively indicate that although ICAM-1 contributes to the mortality of experimental malaria, it is not sufficient for the development of severe experimental malaria. In addition, ICAM-1 expressed on the endothelium or on leukocytes is not required for leukocyte rolling or adhesion to the brain microvasculature of mice during P. berghei malaria. Leukocyte rolling and adhesion in the brain vasculature during P. berghei malaria use different ligands than observed during inflammation in other vascular beds.

Animals↗

Cell adhesion and migration. II. Leukocyte-endothelial cell adhesion in the digestive system.

The adhesion of leukocytes to vascular endothelial cells is a highly coordinated process that is governed by a number of factors, including the expression of specific adhesion glycoproteins, physical forces generated within the microcirculation, and inflammatory mediators released by a variety of activated cells. The digestive system, with its large resident population of immune cells and its tremendous capacity to generate inflammatory mediators, has proven to be a valuable source of information on the mechanisms involved in the regulation of leukocyte-endothelial cell adhesion. This article considers some of the evolving issues that have surfaced as a consequence of the rapidly growing body of literature on this topic. Particular emphasis is devoted to unresolved issues related to the expression and shedding of endothelial cell adhesion molecules, the contribution of capillaries to the inflammatory response, and the role of mast cells, macrophages and lymphocytes in the modulation of leukocyte-endothelial cell adhesion.

Animals↗

CD155/PVR enhances glioma cell dispersal by regulating adhesion signaling and focal adhesion dynamics.

We recently identified the immunoglobulin-CAM CD155/PVR (the poliovirus receptor) as a regulator of cancer invasiveness and glioma migration, but the mechanism through which CD155/PVR controls these processes is unknown. Here, we show that expression of CD155/PVR in rat glioma cells that normally lack this protein enhances their dispersal both in vitro and on primary brain tissue. CD155/PVR expression also reduced substrate adhesion, cell spreading, focal adhesion density, and the number of actin stress fibers in a substrate-dependent manner. Furthermore, we found that expression of CD155/PVR increased Src/focal adhesion kinase signaling in a substrate-dependent manner, enhancing the adhesion-induced activation of paxillin and p130Cas in cells adhering to vitronectin. Conversely, depletion of endogenous CD155/PVR from human glioma cells inhibited their migration, increased cell spreading, and down-regulated the same signaling pathway. These findings implicate CD155/PVR as a regulator of adhesion signaling and suggest a pathway through which glioma and other cancer cells may acquire a dispersive phenotype.

Animals↗

Native LDL increases endothelial cell adhesiveness by inducing intercellular adhesion molecule-1.

Native LDL (n-LDL) increased human umbilical vein endothelial cell (EC) adherence of mononuclear cells. Such phenotypic changes suggest that n-LDL alters the usual expression of cell adhesion molecules to enhance the adhesive properties of the endothelium. To investigate n-LDL mechanisms governing adherence, ECs were exposed to n-LDL in concentrations up to 240 mg/dL for 2 and 4 days. n-LDL-treated ECs bound nearly threefold more phorbol myristate acetate (PMA)-stimulated U937 cells than control ECs but did not bind unstimulated U937 cells. Anti-cellular adhesion molecule-1 (ICAM-1) antibodies blocked PMA-stimulated U937 cell binding to control and n-LDL-treated ECs by more than 80%, suggesting that increases in ICAM-1 may be involved in this increased adherence. Although increases in PMA-stimulated U937 cell binding developed with respect to time and concentration, statistically significant increases were achieved only when n-LDL concentrations exceeded 180 mg cholesterol/dL at day 4. n-LDL increased endothelial adherence of freshly isolated human monocytes more than twofold and neutrophils by almost twofold. Fluorescent-linked immunoassays revealed that n-LDL increased ICAM-1 protein expression by twofold, which corresponded with increased ICAM-1 message levels. n-LDL also appeared to increase E-selectin and vascular cell adhesion molecule-1 message levels, but these changes did not translate into statistically significant differences in protein levels. Taken together, these data indicate that n-LDL increases ICAM-1 expression to enhance the adhesive properties of the endothelium. Such perturbations in EC function likely represent a proinflammatory response to protracted n-LDL exposure and one of the early steps in atherogenesis.

Base Sequence↗

IgG antiendothelial cell autoantibodies from scleroderma patients induce leukocyte adhesion to human vascular endothelial cells in vitro. Induction of adhesion molecule expression and involvement of endothelium-derived cytokines.

IgG autoantibodies that bind human endothelial cells (AECA) were detected by ELISA in 30 of 42 samples of sera from patients with scleroderma. Pretreatment of human umbilical vein endothelial cells with AECA-positive scleroderma sera, or IgG purified from these sera, led to a dose- and time-dependent increase in the ability of the cells to bind human U937 monocytic cells. Threshold-active IgG concentrations were 1-10 micrograms/ml; effects were significant after 3 h and maximal after 6-12 h. IgG from AECA-negative sera or normal sera were without effect. Increased adhesion of U937 cells was accompanied by increased expression of endothelial intercellular adhesion molecule-1, vascular cell adhesion molecule-1, and E-selectin. Transfer of endothelial cell-conditioned media after pretreatment with AECA and immunodepletion of IgG demonstrated the presence of transferable activity that mimicked the effects of AECA. Treatment with neutralizing anticytokine antibodies indicated that IL-1, generated by the endothelial cells in response to AECA, was involved in the upregulation of adhesion molecules and U937 cell adhesion. We conclude that AECA can play a pathogenic role in scleroderma by activating endothelial cells, in part due to autocrine or paracrine actions of IL-1.

Antibodies, Blocking↗

Non-pressure adhesion of a new adhesive restorative resin.

Non-pressure adhesion of a new adhesive restorative resin was investigated employing a new tensile test. The material was adhesive to both enamel and dentin as well as to carious dentin and showed strong adhesion to all substrates tested. Etching further increased the adhesion even to dentin.

Acid Etching, Dental↗

Elevated concentrations of circulating intercellular adhesion molecule 1 (ICAM-1) and of vascular cell adhesion molecule 1 (VCAM-1) in HIV-1 infection.

The aim of this study was to determine whether elevated levels of circulating forms of the soluble adhesion molecules, Intercellular Adhesion Molecule-1 (cICAM-1), Vascular Cell Adhesion Molecule-1 (cVCAM-1) and E-Selectin (cE-Selectin) are observed in the sera of HIV-1 infected individuals as compared to healthy HIV seronegative adults and whether these elevated levels can be correlated with disease progression. Significantly elevated levels of cICAM-1-ranging from 184 to 1116 ng/ml with a mean of 617 ng/ml-and cVCAM-1-ranging from 653 to 3456 ng/ml with a mean of 1500 ng/ml-were observed in the sera of 29 HIV-1 infected individuals as compared to controls-ranging from 152 to 354 ng/ml with a mean of 248 ng/ml for cICAM-1 and from 328 to 792 ng/ml with a mean of 560 ng/ml for cVCAM-1 (P < 0.001). The serum concentrations of cE-Selectin of the HIV-1 infected individuals did not differ from those of the healthy controls. The elevated levels of cICAM-1, cVCAM-1 did not correlate with the CD4 count or the serum concentration of C-reactive protein. However, a significant correlation was observed between the serum concentrations of cVCAM-1 and those of neopterin. Since cICAM-1 as well as cVCAM-1 can interfere with adhesion events leading to immunological functions, it can be suggested that the high amounts of these circulating forms of adhesion molecules, when present in the sera of HIV-1 positive individuals, can further disturb the immune system of these patients. In addition, the present study also suggests that the seric concentrations of cVCAM-1 can be used as pronostic indicators.

Adult↗

Antibodies against the first Ig-like domain of human platelet endothelial cell adhesion molecule-1 (PECAM-1) that inhibit PECAM-1-dependent homophilic adhesion block in vivo neutrophil recruitment.

Platelet endothelial cell adhesion molecule (PECAM-1), a member of the Ig superfamily, is found on endothelial cells and neutrophils and has been shown to be involved in the migration of leukocytes across the endothelium. Adhesion is mediated, at least in part, through binding interactions involving its first N-terminal Ig-like domain, but it is still unclear which sequences in this domain are required for in vivo function. Therefore, to identify functionally important regions of the first Ig-like domain of PECAM-1 that are required for the participation of PECAM-1 in in vivo neutrophil recruitment, a panel of mAbs against this region of PECAM-1 was generated and characterized in in vitro adhesion assays and in an in vivo model of cutaneous inflammation. It was observed that mAbs that disrupted PECAM-1-dependent homophilic adhesion in an L cell aggregation assay also blocked TNF-alpha-induced intradermal accumulation of neutrophils in a transmigration model using human skin transplanted onto SCID mice. Localization of the epitopes of these Abs indicated that these function-blocking Abs mapped to specific regions on either face of domain 1. This suggests that these regions of the first Ig-like domain may contain or be close to binding sites involved in PECAM-1-dependent homophilic adhesion, and thus may represent potential targets for the development of antiinflammatory reagents.

Amino Acid Sequence↗