bay-60-6583 and Disease-Models--Animal

Tissue plasminogen activator (tPA) is administered after ischemic stroke to dissolve intravascular clots, but its use can lead to hemorrhagic transformation (HT). Therapeutic strategies to reduce hemorrhagic complications of tPA might be of benefit for stroke patients. Adenosine A2b receptor (A2bR) plays pivotal roles in regulating vascular protection in peripheral organs. This study explored whether A2bR agonist BAY 60-6583 reduces hemorrhage risk after tPA usage. Using a rat transient middle cerebral artery occlusion model, we showed that mRNA and protein expression of A2bR increased to a greater extent after ischemia-reperfusion than did expression of the other three adenosine receptors (A1, A2a, and A3). tPA administration reduced A2bR expression in ischemic brain microvessels. Post-treatment with BAY 60-6583 (1mg/kg) at the start of reperfusion reduced lesion volume in the absence or presence of tPA (10mg/kg) and attenuated brain swelling, blood-brain barrier disruption, and tPA-exacerbated HT at 24h. Additionally, BAY 60-6583 mitigated sensorimotor deficits in the presence of tPA. BAY 60-6583 inhibited tPA-enhanced matrix metalloprotease-9 activation, probably through elevation of tissue inhibitor of matrix metalloproteinases-1 expression, and thereby reduced degradation of tight junction proteins. These effects would likely protect cerebrovascular integrity. A2bR agonists as an adjuvant to tPA could be a promising strategy for decreasing the risk of HT during treatment for ischemic stroke.

Topics: Adenosine A2 Receptor Agonists; Aminopyridines; Animals; Blood-Brain Barrier; Brain Ischemia; Cerebral Hemorrhage; Disease Models, Animal; Fibrinolytic Agents; Male; Matrix Metalloproteinase 9; Microvessels; Neuroprotective Agents; Random Allocation; Rats, Sprague-Dawley; Receptor, Adenosine A2B; Stroke; Tissue Inhibitor of Metalloproteinase-1; Tissue Plasminogen Activator

To analyze the effect of adenosine on detrusor smooth muscle contraction and to assess age-related changes of adenosine function.. Sustained contractions were induced in young (10-30 days) and old (>60 days) rat detrusor muscle strips by application of 30 mmol/L K(+) and adenosine (0.1-400 µmol/L), which was either applied before raising the K(+) concentration or added to the precontracted muscle strip. Quantitative polymerase chain reaction analyses were used to study adenosine receptor expression in rat and human detrusor specimens.. Pretreatment with adenosine dose-dependently reduced subsequent K(+) -induced contraction in detrusor muscle strips from young rats (half-maximal effect = 40 µmol/L). The residual depolarization-induced contraction strength in young tissue was significantly smaller than in tissue from old animals, showing a greater potency of adenosine in young detrusor samples. Likewise, the relaxing effect of adenosine on precontracted detrusor muscle was also significantly more pronounced in young compared with older detrusor. Quantitative polymerase chain reaction showed an age-related downregulation of the adenosine A2B receptor in rat detrusor tissues, which could be confirmed in human detrusor samples. Furthermore, relaxation of both K(+) -induced as well as carbachol-induced contraction by the specific A2B receptor agonist BAY 60-6583 was significantly more pronounced in young than in old rats.. Adenosine powerfully counteracts contraction of detrusor smooth muscle, which is lost in the aging bladder. This is paralleled by an age-dependent transcriptional downregulation of the low-affinity A2B receptor. Hence, this might be pathophysiologically relevant in conditions of raised adenosine concentrations, such as hyperactive bladder contractility.

Topics: Adenosine; Adenosine A2 Receptor Agonists; Adenosine Triphosphate; Age Factors; Aged; Aminopyridines; Animals; Disease Models, Animal; Down-Regulation; Female; Humans; In Vitro Techniques; Male; Middle Aged; Muscle Contraction; Muscle, Smooth; Rats; Receptor, Adenosine A2B; Urinary Bladder, Overactive

Vascular endothelial growth factor (VEGF) is an angiogenic factor critically involved in tumor progression. Adenosine A2B receptor plays a pivotal role in promoting tumor growth. The aim of this study was to investigate the role of myeloid-derived suppressor cells (MDSCs) in the pro-angiogenic effects of A2B and to determine whether A2B blockade could enhance the effectiveness of anti-VEGF treatment. Mice treated with Bay60-6583, a selective A2B receptor agonist, showed enhanced tumor VEGF-A expression and vessel density. This effect was associated with accelerated tumor growth, which could be reversed with anti-VEGF treatment. Bay60-6583 increased the accumulation of tumor CD11b+Gr1+ cells. Depletion of MDSCs in mice significantly reduced A2B-induced VEGF production. However, A2B receptor stimulation did not directly regulate VEGF expression in isolated tumor myeloid cells. Mechanistically, Bay60-6583-treated melanoma tissues showed increased STAT3 activation. Inhibition of STAT3 significantly decreased the pro-tumor activity of Bay60-6583 and reduced tumor VEGF expression. Pharmacological blockade of A2B receptor with PSB1115 significantly reduced tumor growth by inhibiting tumor angiogenesis and increasing T cells numbers within the tumor microenvironment. These effects are, at least in part, dependent on impaired tumor accumulation of Gr1+ cells upon A2B receptor blockade. PSB1115 increased the effectiveness of anti-VEGF treatment.

Topics: Aminopyridines; Angiogenesis Inducing Agents; Angiogenesis Inhibitors; Animals; Antigens, Ly; CD11b Antigen; Disease Models, Animal; Female; Flow Cytometry; Melanoma; Melanoma, Experimental; Mice; Mice, Inbred C57BL; Myeloid Cells; Neovascularization, Pathologic; Receptor, Adenosine A2B; Skin Neoplasms; T-Lymphocytes; Tumor Microenvironment; Vascular Endothelial Growth Factor A

Inflammation is responsible for secondary organ failure after trauma and hemorrhagic shock (T/HS). Adenosine, acting through four G protein-coupled cell surface receptors, A1, A2A, A2B, and A3, exerts a number of tissue protective and anti-inflammatory effects. The goal of the present study was to test the effect of A2B adenosine receptor stimulation on T/HS-induced organ injury and inflammation in rats. Rats after T/HS were resuscitated with Ringer's lactate containing the A2B receptor agonist BAY 60-6583 or its vehicle. We found that BAY 60-6583 decreased T/HS-induced lung permeability and plasma creatine kinase levels but failed to affect T/HS-induced lung neutrophil infiltration and IκBα expression and plasma alanine aminotransferase levels. Thus, we conclude that stimulation of A2B receptors protects against T/HS-induced lung and muscle injury.

Topics: Acute Lung Injury; Aminopyridines; Animals; Blotting, Western; Disease Models, Animal; Inflammation; Male; Purinergic P1 Receptor Agonists; Rats; Rats, Sprague-Dawley; Receptor, Adenosine A2B; Shock, Hemorrhagic; Wounds and Injuries

The A(2B) adenosine receptor (A(2B)R) is highly expressed in macrophages and vascular smooth muscle cells and has been established as an important regulator of inflammation and vascular adhesion. Recently, it has been demonstrated that A(2B)R deficiency enhances neointimal lesion formation after vascular injury. Therefore, we hypothesize that A(2B)R agonism protects against injury-induced intimal hyperplasia.. Apolipoprotein E-deficient mice were fed a Western-type diet for 1 week, after which the left common carotid artery was denuded. Mice were treated with the A(2B) receptor agonist BAY60-6583 or vehicle control for 18 days. Interestingly, lumen stenosis as defined by the neointima/lumen ratio was inhibited by treatment with the A(2B) receptor agonist, caused by reduced smooth muscle cell proliferation. Collagen content was significantly increased in the BAY60-6583-treated mice, whereas macrophage content remained unchanged. In vitro, vascular smooth muscle cell proliferation decreased dose dependently whereas collagen content of cultured smooth muscle cells was increased by BAY60-6583.. Our data show that activation of the adenosine A(2B) receptor protects against vascular injury, while it also enhances plaque stability as indicated by increased collagen content. These outcomes thus point to A(2B) receptor agonism as a new therapeutic approach in the prevention of restenosis.

Topics: Adenosine A2 Receptor Agonists; Aminopyridines; Animals; Apolipoproteins E; Cardiovascular Agents; Carotid Artery Injuries; Carotid Artery, Common; Carotid Stenosis; Cell Adhesion; Cell Proliferation; CHO Cells; Collagen; Cricetinae; Cricetulus; Dietary Fats; Disease Models, Animal; Dose-Response Relationship, Drug; Endothelium, Vascular; Female; HEK293 Cells; Humans; Mice; Mice, Knockout; Muscle, Smooth, Vascular; Myocytes, Smooth Muscle; Neointima; Neutrophil Activation; Neutrophils; Platelet Activation; Receptor, Adenosine A2B; Time Factors; Transfection

Sepsis and septic acute lung injury are among the leading causes for morbidity and mortality of critical illness. Extracellular adenosine is a signaling molecule implicated in the cellular adaptation to hypoxia, ischemia, or inflammation. Therefore, we pursued the role of the A2B adenosine receptor (AR) as potential therapeutic target in endotoxin-induced acute lung injury. We gained initial insight from in vitro studies of cultured endothelia or epithelia exposed to inflammatory mediators showing time-dependent induction of the A2BAR (up to 12.9 + or - 3.4-fold, p < 0.05). Similarly, murine studies of endotoxin-induced lung injury identified an almost 4.6-fold induction of A2BAR transcript and corresponding protein induction with LPS exposure. Studies utilizing A2BAR promoter constructs and RNA protection assays indicated that A2BAR induction involved mRNA stability. Functional studies of LPS-induced lung injury revealed that pharmacological inhibition or genetic deletion of the A2BAR was associated with dramatic increases in lung inflammation and histologic tissue injury. Studies of A2BAR bone marrow chimeric mice suggested pulmonary A2BAR signaling in lung protection. Finally, studies with a specific A2BAR agonist (BAY 60-6583) demonstrated attenuation of lung inflammation and pulmonary edema in wild-type but not in gene-targeted mice for the A2BAR. These studies suggest the A2BAR as potential therapeutic target in the treatment of endotoxin-induced forms of acute lung injury.

Topics: Acetamides; Acute Lung Injury; Adenosine A2 Receptor Agonists; Adenosine A2 Receptor Antagonists; Administration, Inhalation; Aminopyridines; Animals; Bone Marrow Transplantation; Cell Line; Cell Line, Tumor; Disease Models, Animal; Humans; Inflammation Mediators; Lipopolysaccharides; Male; Mice; Mice, Inbred C57BL; Mice, Knockout; Mice, Mutant Strains; Purines; Receptor, Adenosine A2B; Sepsis; Signal Transduction