The purpose of the present study was to investigate the effect of glutamate scavenger oxaloacetate (OA) combined with CGS21680, an adenosine A2A receptor (A2AR) agonist, on acute traumatic brain injury (TBI), and to elucidate the underlying mechanisms. C57BL/6J mice were subjected to moderate-level TBI by controlled cortical impact, and then were treated with OA, CGS21680, or OA combined with CGS21680 at acute stage of TBI. At 24 h post TBI, neurological severity score, brain water content, glutamate concentration in cerebrospinal fluid (CSF), mRNA and protein levels of IL-1β and TNF-α, mRNA level and activity of glutamate oxaloacetate aminotransferase (GOT), and ATP level of brain tissue were detected. The results showed that neurological deficit, brain water content, glutamate concentration in CSF, and the inflammatory cytokine IL-1β and TNF-α production were exacerbated in CGS21680 treated mice. Administrating OA suppressed the rise of both glutamate concentration in CSF and brain water content, and elevated the ATP level of cerebral tissue. More interestingly, neurological deficit, brain edema, glutamate concentration, IL-1β and TNF-α levels were ameliorated significantly in mice treated with OA combined with CGS21680. The combined treatment exhibited better therapeutic effects than single OA treatment. We also observed that GOT activity was enhanced in single CGS21680 treatment group, and both the GOT mRNA level and GOT activity were up-regulated in early-stage combined treatment group. These results suggest that A2AR can improve the efficiency of GOT and potentiate the ability of OA to metabolize glutamate. This may be the mechanism that A2AR activation in combination group augmented the neuroprotective effect of OA rather than aggravated the brain damages. Taken together, the present study provides a new insight for the clinical treatment of TBI with A2AR agonists and OA.
Adenosine A2 Receptor Agonists/therapeutic use* ; Adenosine Triphosphate ; Animals ; Brain Injuries/metabolism* ; Brain Injuries, Traumatic/metabolism* ; Glutamic Acid ; Mice ; Mice, Inbred C57BL ; Neuroprotective Agents/therapeutic use* ; Oxaloacetic Acid/therapeutic use* ; RNA, Messenger ; Receptor, Adenosine A2A/metabolism* ; Tumor Necrosis Factor-alpha/genetics* ; Water

Adenosine is a metabolite produced abundantly in the tumor microenvironment, dampening immune response in inflamed tissues via adenosine A2A receptor (A2AR) which is widely expressed on immune cells, inhibiting anti-tumor immune response accordingly. Therefore, blocking adenosine signaling pathway is of potential to promote anti-tumor immunity. This review briefly introduces adenosine signaling pathway, describes its role in regulating tumor immunity and highlights A2AR blockade in cancer therapy. Prospective anti-tumor activity of adenosine/A2AR inhibition has been revealed by preclinical data, and a number of clinical trials of A2AR antagonists are under way. Primary results from clinical trials suggest that A2AR antagonists are well tolerated in cancer patients and are effective both as monotherapy and in combination with other therapies. In the future, finding predictive biomarkers are critical to identify patients most likely to benefit from adenosine pathway blockade, and further researches are needed to rationally combine A2AR antagonists with other anti-tumor therapies.
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Adenosine/therapeutic use* ; Adenosine A2 Receptor Antagonists/therapeutic use* ; Humans ; Lung Neoplasms ; Receptor, Adenosine A2A/metabolism* ; Tumor Microenvironment

The relationship between adenosine receptor (AdoR) and myocardial ischemia (MI), effect of acupuncture for MI and action mechanism of acupuncture improving MI by regulating AdoR are summarized. The existing researches have preliminarily reflected that the improvement of MI treated with acupuncture may be achieved by influencing the expression of AdoR. However, there are still some limitations, e.g. most of the research regimens are single-acupoint, the research results are not entirely consistent and the interaction of AdoRs are ignored, all these need to be further verified and supplemented.
Acupuncture ; Acupuncture Points ; Acupuncture Therapy ; Humans ; Myocardial Ischemia/therapy* ; Receptors, Purinergic P1

BACKGROUND: The pain-relief properties of tricyclic antidepressants can be attributed to several actions. Recent observations suggest that adenosine is involved in the antinociceptive effect of amitriptyline. The A3 adenosine receptor (A3AR) is the only adenosine subtype overexpressed in inflammatory and cancer cells. This study was performed to investigate the role of A3AR in the anti-nociceptive effect of amitriptyline. METHODS: Spinal nerve-ligated neuropathic pain was induced by ligating the L5 and L6 spinal nerves of male Sprague-Dawley rats. The neuropathic rats were randomly assigned to one of the following three groups (8 per group): a neuropathic pain with normal saline group, a neuropathic pain with amitriptyline group, and a neuropathic pain with amitriptyline and 3-ethyl-5-benzyl- 2-methyl-4-phenylethynyl-6-phenyl-1,4-(±)-dihydropyridine-3,5-dicarboxylate (MRS) group. Amitriptyline or saline was administered intraperitoneally and 3-ethyl-5-benzyl-2-methyl-4-phenylethynyl-6-phenyl-1,4-(±)-dihydropyridine-3,5-dicarboxylate (MRS-1191), an A3AR antagonist, was injected subcutaneously immediately before amitriptyline administration. The level of extracellular signal-regulated kinase P44/42 (ERK1/2), cyclic AMP response element-binding protein (CREB), and proinflammatory cytokines were assessed using immunoblotting or reverse-transciption polymerase chain reaction. RESULTS: Amitriptyline increased the mechanical withdrawal threshold of the neuropathic rats. The level of phospho-ERK1/2 and phospho-CREB proteins, and proinflammatory cytokines produced by spinal nerve ligation were significantly reduced by amitriptyline administration. However, the use of MRS-1191 before amitriptyline administration not only reduced the threshold of mechanical allodynia, but also increased the signaling protein and proinflammatory cytokine levels, which were reduced by amitriptyline. CONCLUSIONS: The results of this study suggest that the anti-nociceptive effect of amitriptyline involves the suppression of ERK1/2 and CREB signaling proteins, and A3AR activation also affects the alleviation of the inflammatory response.
Adenosine ; Amitriptyline ; Animals ; Antidepressive Agents, Tricyclic ; Cyclic AMP Response Element-Binding Protein ; Cytokines ; Humans ; Hyperalgesia ; Immunoblotting ; Ligation ; Male ; Neuralgia ; Phosphotransferases ; Polymerase Chain Reaction ; Rats ; Rats, Sprague-Dawley ; Receptors, Purinergic P1 ; Spinal Nerves

Acute kidney injury (AKI) due to renal ischemia reperfusion (IR) is a major clinical problem without effective therapy and is a significant and frequent cause of morbidity and mortality during the perioperative period. Although the pathophysiology of ischemic AKI is not completely understood, several important mechanisms of renal IR-induced AKI have been studied. Renal ischemia and subsequent reperfusion injury initiates signaling cascades mediating renal cell necrosis, apoptosis, and inflammation, leading to AKI. Better understanding of the molecular and cellular pathophysiological mechanisms underlying ischemic AKI will provide more targeted approach to prevent and treat renal IR injury. In this review, we summarize important mechanisms of ischemic AKI, including renal cell death pathways and the contribution of endothelial cells, epithelial cells, and leukocytes to the inflammatory response during ischemic AKI. Additionally, we provide some updated potential therapeutic targets for the prevention or treatment of ischemic AKI, including Toll-like receptors, adenosine receptors, and peptidylarginine deiminase 4. Finally, we propose mechanisms of ischemic AKI-induced liver, intestine, and kidney dysfunction and systemic inflammation mainly mediated by Paneth cell degranulation as a potential explanation for the high mortality observed with AKI.
Acute Kidney Injury ; Apoptosis ; Cell Death ; Cell Degranulation ; Endothelial Cells ; Epithelial Cells ; Inflammation ; Intestines ; Ischemia ; Kidney ; Leukocytes ; Liver ; Mortality ; Necrosis ; Negotiating ; Perioperative Period ; Receptors, Purinergic P1 ; Reperfusion ; Reperfusion Injury ; Toll-Like Receptors

OBJECTIVE: To explore the action mechanism of acupoint selection along meridians to improve adenosine receptor in myocardial ischemia (MI) rats by comparing the effects of acupoint selection along meridians, acupoint selection at other meridians and non-acupoint on expression of adenosine receptor. METHODS: A total of 120 SD rats were randomly divided into a blank group, a sham operation group, a model group, an acupoint-selection-along-meridians (ASAM) group, an acupoint-selection-at-other-meridians (ASAOM) group and a non-acupoint group, 20 rats in each group. The model of MI was not made in the blank group; the left anterior descending coronary artery was not ligated after thoracotomy in the sham operation group; the model of MI was made but acupuncture was not given in the model group. After the model of MI was made, electroacupuncture (EA) was applied at "Neiguan" (PC 6) in the ASAM group, at "Hegu" (LI 4) in the ASAOM group, and at the area between the third and fourth metatarsal bone in the non-acupoint group. EA was given 20 min per treatment, once a day for 5 days. After treatment, the TTC staining was used to detect myocardial infarction, the Tunel method was used to detect cardiomyocyte apoptosis, and the immunohistochemistry was used to detect the expression of adenosine receptors A1, A2a and A2b. RESULTS: Compared with the blank group and the sham operation group, the percentage of myocardial infarction and apoptotic rate of myocardial cells in the model group were increased significantly (<0.01). After EA treatment, compared with the model group, the percentage of myocardial infarction and apoptotic rate of myocardial cells in the ASAM group were decreased significantly (<0.01), and the expression levels of adenosine receptors A1, A2a and A2b were increased significantly (<0.01). The percentage of myocardial infarction and apoptotic rate of myocardial cells in the ASAM group were significantly lower than those in the ASAOM group and the non-acupoint group (<0.01), and the expression levels of adenosine receptors A1, A2a and A2b in the ASAM group were significantly higher than those in the ASAOM group and non-acupoint group (<0.01). CONCLUSION Compared with acupoint selection at other meridians or non-acupoints, acupoint selection along meridians can effectively regulate the expression of adenosine receptors A1, A2a and A2b, improve the condition of myocardial infarction, inhibit myocardial cell apoptosis, and consequently protect ischemic myocardium.
Acupuncture Points ; Animals ; Electroacupuncture ; Humans ; Meridians ; Myocardial Ischemia ; therapy ; Random Allocation ; Rats ; Rats, Sprague-Dawley ; Receptors, Purinergic P1

Most diabetic patients experience diabetic mellitus (DM) urinary bladder dysfunction. A number of studies evaluate bladder smooth muscle contraction in DM. In this study, we evaluated the change of bladder smooth muscle contraction between normal rats and DM rats. Furthermore, we used pharmacological inhibitors to determine the differences in the signaling pathways between normal and DM rats. Rats in the DM group received an intraperitoneal injection of 65 mg/kg streptozotocin and measured blood glucose level after 14 days to confirm DM. Bladder smooth muscle contraction was induced using acetylcholine (ACh, 10⁻⁴ M). The materials such as, atropine (a muscarinic receptor antagonist), U73122 (a phospholipase C inhibitor), DPCPX (an adenosine A1 receptor antagonist), udenafil (a PDE5 inhibitor), prazosin (an α₁-receptor antagonist), papaverine (a smooth muscle relaxant), verapamil (a calcium channel blocker), and chelerythrine (a protein kinase C inhibitor) were pre-treated in bladder smooth muscle. We found that the DM rats had lower bladder smooth muscle contractility than normal rats. When prazosin, udenafil, verapamil, and U73122 were pre-treated, there were significant differences between normal and DM rats. Taken together, it was concluded that the change of intracellular Ca²⁺ release mediated by PLC/IP3 and PDE5 activity were responsible for decreased bladder smooth muscle contractility in DM rats.
Acetylcholine ; Animals ; Atropine ; Blood Glucose ; Calcium Channels ; Humans ; Injections, Intraperitoneal ; Muscle, Smooth* ; Papaverine ; Prazosin ; Protein Kinase C ; Rats* ; Receptor, Adenosine A1 ; Receptors, Muscarinic ; Streptozocin ; Type C Phospholipases ; Urinary Bladder* ; Verapamil

Luteolin, a widespread flavonoid, has been known to have neuroprotective activity against various neurologic diseases such as epilepsy, and Alzheimer’s disease. However, little information is available regarding the hypnotic effect of luteolin. In this study, we evaluated the hypnotic effect of luteolin and its underlying mechanism. In pentobarbital-induced sleeping mice model, luteolin (1, and 3 mg/kg, p.o.) decreased sleep latency and increased the total sleep time. Through electroencephalogram (EEG) and electromyogram (EMG) recording, we demonstrated that luteolin increased non-rapid eye movement (NREM) sleep time and decreased wake time. To evaluate the underlying mechanism, we examined the effects of various pharmacological antagonists on the hypnotic effect of luteolin. The hypnotic effect of 3 mg/kg of luteolin was not affected by flumazenil, a GABAA receptor-benzodiazepine (GABAAR-BDZ) binding site antagonist, and bicuculine, a GABAAR-GABA binding site antagonist. On the other hand, the hypnotic effect of 3 mg/kg of luteolin was almost completely blocked by caffeine, an antagonist for both adenosine A1 and A2A receptor (A1R and A2AR), 8-Cyclopentyl-1,3-dipropylxanthine (DPCPX), an A1R antagonist, and SCH-58261, an A2AR antagonist. From the binding affinity assay, we have found that luteolin significantly binds to not only A1R but also A2AR with IC₅₀ of 1.19, 0.84 μg/kg, respectively. However, luteolin did not bind to either BDZ-receptor or GABAAR. From these results, it has been suggested that luteolin has hypnotic efficacy through A1R and A2AR binding.
Adenosine ; Animals ; Binding Sites ; Caffeine ; Electroencephalography ; Epilepsy ; Eye Movements ; Flumazenil ; Hand ; Hypnotics and Sedatives ; Luteolin ; Mice ; Receptor, Adenosine A1 ; Receptor, Adenosine A2A ; Sleep Initiation and Maintenance Disorders

OBJECTIVE: To explore the role of the low-affinity A2b adenosine receptors (Adora2b) in pulmonary microvascular endothelial inflammation induced by lipopolysaccharide and its mechanism. METHODS: Rat pulmonary microvascular endothelial cells (PMVECs) were isolated and cultured in vitro. After serum deprivation for 24 hours, cells were pretreated with Adora2b specific agonist BAY60-6583 (0.1, 1, 10 μmol/L) or Adora2b specific antagonist PSB1115 (1 μmol/L) for 1 hour, respectively, and then challenged with LPS (100 μg/L). Cells without treatment were served as the control group, and those treated with LPS, BAY60-6583 or PSB1115 alone were served as single challenge groups. After incubation with specific drugs for 24 hours, the apoptosis of PMVECs was analyzed by flow cytometry using Annexin V/propidium iodide (PI) technique. The levels of early inflammatory factors in cultured medium were measured using enzyme linked immunosorbent assay (ELISA). The mRNA expressions of chemotactic factors and adhesion molecules were determined by real-time quantitative-polymerase chain reaction (RT-qPCR). Polymorph nuclear neutrophils (PMNs) from venous blood of healthy rats were isolated, and PMN migration through PMVECs monolayer under stimulation of drugs was observed in transwell inserts. The monolayer permeability of PMVECs after adhesion of PMNs was determined by fluorescein isothiocyanate (FITC)-albumin assay. Oxidative stress was detected by DCFH-DA assay. RESULTS: Compared with the control group, more cells entered into the apoptosis stage after LPS challenge. Meanwhile, the levels of interleukin-1β (IL-1β) and tumor necrosis factor-α (TNF-α) in cultured medium were significantly increased, as well as the mRNA expressions of chemotactic factors [C-X-C motif chemokine ligand 1 (CXCL-1), CXCL-3 and monocyte chemoattractant protein-1 (MCP-1)] and adhesion molecules [E-selectin, intercellular adhesion molecule-1 (ICAM-1) and vascular cell adhesion molecule-1 (VCAM-1)]. More PMNs migrated through PMVECs following adhesion and the monolayer permeability of PMVECs was rapidly enhanced. The oxidative stress was upregulated. Compared with LPS group, BAY60-6583 pretreatment could dose-dependently decrease the rate of apoptosis, attenuate trans-endothelial migration of PMNs and decrease the endothelial cell barrier leakage. There were significant differences even after incubation of 0.1 μmol/L BAY60-6583 [apoptosis rate: (21.12±2.12)% vs. (27.66±3.57)%, number of migrated PMNs/HP: 260.60±18.24 vs. 290.20±16.48, permeability coefficient (Pd, ×10^-6 cm/s): 28.28±2.04 vs. 32.55±2.13, all P < 0.05]. Meanwhile, BAY60-6583 pretreatment also downregulated the levels of early proinflammatory factors in a dose-dependent manner as well as the mRNA expressions of chemotactic factors and adhesion molecules. The statistic difference was significant while treated with 1 μmol/L BAY60-6583 [IL-1β (ng/L): 475.75±63.15 vs. 755.25±67.42, TNF-α (ng/L): 560.25±69.96 vs. 818.75±60.92, CXCL-1 mRNA (2^-ΔΔCt): 3.57±0.28 vs. 5.27±0.69, CXCL-3 mRNA (2^-ΔΔCt): 4.56±0.48 vs. 7.32±0.54, MCP-1 mRNA (2^-ΔΔCt): 2.21±0.31 vs. 3.35±0.21, E-selectin mRNA (2^-ΔΔCt): 4.64±0.09 vs. 7.28±0.73, ICAM-1 mRNA (2^-ΔΔCt): 4.14±0.30 vs. 5.89±0.25, VCAM-1 mRNA (2^-ΔΔCt): 2.23±0.19 vs. 2.92±0.33, all P < 0.05]. Furthermore, pretreatment of 10 μmol/L BAY60-6583 could decrease the oxidative stress [reactive oxygen species (RFU): 629.05±33.10 vs. 781.45±64.59, P < 0.05]. Contrast, PSB1115 pretreatment aggravated apoptosis of PMVECs after LPS incubation [(34.36±4.57)% vs. (27.66±3.57)%], upregulated expressions of proinflammatory and chemotactic factors as well as adhesion molecules [IL-1β (ng/L): 889.00±63.11 vs. 755.25±67.42, TNF-α (ng/L): 939.00±43.44 vs. 818.75±60.92, CXCL-1 mRNA (2^-ΔΔCt): 6.66±0.65 vs. 5.27±0.69, CXCL-3 mRNA (2^-ΔΔCt): 10.42±0.51 vs. 7.32±0.54, MCP-1 mRNA (2^-ΔΔCt): 4.85±0.34 vs. 3.35±0.21, E-selectin mRNA (2^-ΔΔCt): 8.42±0.47 vs. 7.28±0.73, ICAM-1 mRNA (2^-ΔΔCt): 7.46±0.72 vs. 5.89±0.25, VCAM-1 mRNA (2^-ΔΔCt): 4.35±0.26 vs. 2.92±0.33], aggravated trans-endothelial migration of PMNs (cells/HP: 348.40±22.68 vs. 290.20±16.48), enhanced the leakage of PMVECs monolayer [Pd (×10^-6 cm/s): 39.65±2.69 vs. 32.55±2.13] and increased oxidative stress in PMVECs [reactive oxygen species (RFU): 847.04±29.26 vs. 781.45±64.59], with statistically significant difference (all P < 0.05). CONCLUSIONS Activation of endothelial Adora2b attenuates LPS-induced pulmonary microvascular inflammation by decreasing the release of early inflammatory factors, downregulating expressions of chemotactic factors and adhesion molecules, attenuating trans-endothelial migration of PMNs and oxidative stress in PMVECs, which suggest endothelial Adora2b is apotential anti-inflammatory target in the treatment of LPS-induced acute lung injury.
Animals ; Endothelial Cells ; Inflammation ; Lipopolysaccharides/metabolism* ; Pneumonia ; Rats ; Receptor, Adenosine A2B/metabolism* ; Tumor Necrosis Factor-alpha

Polydeoxyribonucleotide (PDRN) is safe and effective in wound healing, cellular growth, synthesis of extracellular matrix protein, and inflammation reduction via activation of adenosine A2 receptors. We report a 28-year-old male patient treated with PDRN injections for chronic non-healing wound refractory to negative pressure wound therapy, skin graft, or growth factors. Three injections of PDRN were administered at the wound site into the anterior and medial sides of the left stump on the 1st, 4th, and 9th days of hospitalization. The PDRN ameliorated wound healing by enhancing cell growth, tissue repair, and angiogenesis. PDRN application represents a potential treatment for non-healing wounds obviating the need for additional therapies, and hospitalization, as well as improve patient’s activities of daily living.
Activities of Daily Living ; Adult ; Amputees* ; Extracellular Matrix ; Hospitalization ; Humans ; Inflammation ; Intercellular Signaling Peptides and Proteins ; Male ; Negative-Pressure Wound Therapy ; Polydeoxyribonucleotides ; Receptors, Adenosine A2 ; Skin ; Transplants ; Wound Healing ; Wounds and Injuries*