Effects of gestational and breastfeeding caffeine exposure in adenosine A1 agonist-induced antinociception of infant rats.

OBJECTIVES: Caffeine is extensively consumed as a psychostimulant drug, acting on A1 and A2A adenosine receptors blockade. Chronic exposure to caffeine during gestation and breast-feeding may be involved in infant rat's behavioral and biochemical alterations. Our goal was to evaluate the effect of chronic caffeine exposure during gestation and breast-feeding in the functionality of adenosine A1 receptors in infant rats at P14. NTPDase and 5'-nucleotidase activities were also evaluated. METHODS: Mating of adult female Wistar rats was confirmed by presence of sperm in vaginal smears. Rats were divided into three groups on the first day of pregnancy: (1) control: tap water, (2) caffeine: 0.3 g/L until P14, and (3) washout caffeine: caffeine was changed to tap water at P7. Evaluation of nociceptive response was performed at P14 using hot plate (HP) and tail-flick latency (TFL) tests. A1 receptor involvement was assessed using caffeine agonist (CPA) and antagonist (DPCPX). Enzymatic activities assays were conducted in the spinal cord. RESULTS: Gestational and breastfeeding exposure to caffeine (caffeine and washout groups) did not induce significant alterations in thermal nociceptive thresholds (HP and TF tests). Both caffeine groups did not show analgesic response induced by CPA when compared to the control group at P14, indicating chronic exposure to caffeine in the aforementioned periods inhibits the antinociceptive effects of the systemic A1 receptor agonist administration. No effect was observed upon ectonucleotidase activities. CONCLUSIONS: Our results demonstrate that chronic caffeine exposure in gestational and breastfeeding alters A1-mediated analgesic response in rats.

Role of the P2X7 receptor in in vitro and in vivo glioma tumor growth.

Human glioblastoma cells are strikingly refractory to ATP-stimulated, P2X7 receptor (P2X7R)-mediated cytotoxicity. To elucidate the mechanistic basis of this feature, we investigated P2X7R-dependent responses in wild type and P2X7R-transfected U138 cells. Mouse GL261 glioma cells were used as an additional control. Here, we report that wild type U138 glioma cells expressed the P2X7R to very low level. Contrary to human U138 cells, mouse GL261 cells showed strong P2X7R expression and P2X7R-dependent responses. Transfection of wild type P2RX7 into U138 cells fully restored P2X7R-dependent responses. P2RX7 transfection conferred a negligible in vitro growth advantage to U138 cells, while strongly accelerated in vivo growth. In silico analysis showed that the P2RX7 gene is seldom mutated in specimens from glioblastoma multiforme (GBM) patients. These observations suggest that the P2X7R might be an important receptor promoting GBM growth.

Methotrexate up-regulates ecto-5'-nucleotidase/CD73 and reduces the frequency of T lymphocytes in the glioblastoma microenvironment.

Glioblastoma multiforme (GBM) is a deadly cancer characterized by a pro-tumoral immune response. T-regulatory (Treg) lymphocytes suppress effector immune cells through cytokine secretion and the adenosinergic system. Ecto-5'-nucleotidase/CD73 plays a crucial role in Treg-mediated immunosuppression in the GBM microenvironment (GME). Methotrexate (MTX) is an immunosuppressive drug that can increase the extracellular concentration of adenosine. In this manuscript, C6 GBM cells were treated with 1.0 µM MTX, and ecto-5'-nucleotidase/CD73 expression and extracellular AMP metabolism were analyzed in vitro. For in vivo studies, rats with implanted GBM were treated for 10 days with MTX-loaded lipid-core nanocapsules (MTX-LNCs, 1 mg/kg/day). The activity of ectonucleotidase and the expression of NTPDase1/CD39 and ecto-5'-nucleotidase/CD73 were measured. The frequencies of T lymphocytes (CD3(+)CD4(+), CD3(+)CD8(+), and CD4(+)CD25(high)CD39(+)) were quantified. In vitro, treatment with MTX increased CD73 expression and activity in C6 cells, which is in agreement with higher levels of extracellular adenosine. In vivo, MTX-LNC treatment increased CD39 expression on CD3(+)CD8(+) lymphocytes. In addition, MTX-LNC treatment up-regulated CD73 expression in tissue isolated from GBM, a finding that is in agreement with the higher activity of this enzyme. More specifically, the treatment increased CD73 expression on CD3(+)CD4(+) and CD3(+)CD8(+) lymphocytes. Treatment with MTX-LNCs decreased the frequencies of T-cytotoxic, T-helper, and Treg lymphocytes in the GME. Although more studies are necessary to better understand the complex cross-talk mediated by supra-physiological concentrations of adenosine in the GME, these studies demonstrate that MTX treatment increases CD73 enzyme expression and AMP hydrolysis, leading to an increase in adenosine production and immunosuppressive capability.

Quercetin derivative induces cell death in glioma cells by modulating NF-κB nuclear translocation and caspase-3 activation.

Treated glioblastoma multiforme (GBM) patients only survive 6 to 14months after diagnosis; therefore, the development of novel therapeutic strategies to treat gliomas remains critically necessary. Considering that phenolic compounds, like quercetin, have the potential to be used in the chemotreatment of gliomas and that some flavonoids exhibit the ability to cross the BBB, in the present study, we investigated the antitumor effect of flavonoids (including chalcones, flavones, flavanones and flavonols). Initially their activities were tested in C6 glioma cells screened using the MTT method, resulting in the selection of chalcone 2 whose feasibility was confirmed by a Trypan Blue exclusion assay in the low µM range on C6 glioma cells. Cell cycle and apoptotic death analyses on C6 glioma cells were also performed, and chalcone 2 increased the apoptosis of the cells but did not alter the cell cycle progression. In addition, treatments with these two compounds were not cytotoxic to hippocampal organotypic cultures, a model of healthy neural cells. Furthermore, the results indicated that 2 induced apoptosis by inhibition of NF-κB and activation of active caspase-3 in glioma cells, suggesting that it is a potential prototype to develop new treatments for GBM in the future.

Ecto-5'-Nucleotidase Overexpression Reduces Tumor Growth in a Xenograph Medulloblastoma Model.

BACKGROUND: Ecto-5'-nucleotidase/CD73 (ecto-5'-NT) participates in extracellular ATP catabolism by converting adenosine monophosphate (AMP) into adenosine. This enzyme affects the progression and invasiveness of different tumors. Furthermore, the expression of ecto-5'-NT has also been suggested as a favorable prognostic marker, attributing to this enzyme contradictory functions in cancer. Medulloblastoma (MB) is the most common brain tumor of the cerebellum and affects mainly children. MATERIALS AND METHODS: The effects of ecto-5'-NT overexpression on human MB tumor growth were studied in an in vivo model. Balb/c immunodeficient (nude) 6 to 14-week-old mice were used for dorsal subcutaneous xenograph tumor implant. Tumor development was evaluated by pathophysiological analysis. In addition, the expression patterns of adenosine receptors were verified. RESULTS: The human MB cell line D283, transfected with ecto-5'-NT (D283hCD73), revealed reduced tumor growth compared to the original cell line transfected with an empty vector. D283hCD73 generated tumors with a reduced proliferative index, lower vascularization, the presence of differentiated cells and increased active caspase-3 expression. Prominent A1 adenosine receptor expression rates were detected in MB cells overexpressing ecto-5'-NT. CONCLUSION: This work suggests that ecto-5'-NT promotes reduced tumor growth to reduce cell proliferation and vascularization, promote higher differentiation rates and initiate apoptosis, supposedly by accumulating adenosine, which then acts through A1 adenosine receptors. Therefore, ecto-5'-NT might be considered an important prognostic marker, being associated with good prognosis and used as a potential target for therapy.

Pharmacological Improvement and Preclinical Evaluation of Methotrexate-Loaded Lipid-Core Nanocapsules in a Glioblastoma Model.

Glioblastoma multiforme is a devastating cerebral tumor with an exceedingly poor prognosis. Methotrexate (MTX) is a folic acid analogue that inhibits DNA synthesis by binding to dihydrofolate reductase. Biodegradable nanoparticles are emerging as a promising system for drug delivery to specific tissues. The aims of the current study were pharmacological improvement and preclinical evaluation of MTX-loaded lipid-core nanocapsules (MTX-LNCs) in a glioblastoma model. Cell viability was assessed using the MTT assay, and the cell cycle was characterized by flow cytometry analysis of propidium iodide staining. Apoptosis was measured using an AnnexinV kit and by examining active caspase-3 immunocontent. In vivo glioma implantation was performed in rats, followed by measurement of the tumor size and tumoral apoptosis, BCL-2 immunohistochemistry and analyses of toxicological parameters. MTX-LNCs with increased encapsulation efficiency were successfully prepared. Our in vitro results showed a decrease in glioma cell viability after MTX-LNC treatment that was preceded by cell cycle arrest, leading the cells to undergo apoptotic death, as indicated by AnnexinV staining and increased active caspase-3 protein levels. In the in vivo glioma model, we observed a decrease in the tumor size and an increase in apoptosis in the tumor microenvironment (based on the AnnexinV assay and BCL-2 measurement). MTX-LNC treatment decreased the leukocyte number but altered neither toxicological tissue marker expression nor metabolic parameters. The present results reveal that MTX-LNCs represented an efficient formulation in a preclinical model of glioma and are a potential candidate for clinical trials.

Nucleotide receptors control IL-8/CXCL8 and MCP-1/CCL2 secretions as well as proliferation in human glioma cells.

Glioma cells release cytokines to stimulate inflammation that facilitates cell proliferation. Here, we show that Lipopolysaccharide (LPS) treatment could induce glioma cells to proliferate and this process was dependent on nucleotide receptor activation as well as interleukin-8 (IL-8/CXCL8) secretion. We observed that extracellular nucleotides controlled IL-8/CXCL8 and monocyte chemoattractant protein 1 (MCP-1/CCL2) release by U251MG and U87MG human glioma cell lines via P2X7 and P2Y6 receptor activation. The LPS-induced release of these cytokines was also modulated by purinergic receptor activation since IL-8 and MCP-1 release was decreased by the nucleotide scavenger apyrase as well as by the pharmacological P2Y6 receptor antagonists suramin and MRS2578. In agreement with these observations, the knockdown of P2Y6 expression decreased LPS-induced IL-8 release as well as the spontaneous release of IL-8 and MCP-1, suggesting an endogenous basal release of nucleotides. Moreover, high millimolar concentrations of ATP increased IL-8 and MCP-1 release by the glioma cells stimulated with suboptimal LPS concentration which were blocked by P2X7 and P2Y6 antagonists. Altogether, these data suggest that extracellular nucleotides control glioma growth via P2 receptor-dependent IL-8 and MCP-1 secretions.

Extracellular mycobacterial DnaK polarizes macrophages to the M2-like phenotype.

Macrophages are myeloid cells that play an essential role in inflammation and host defense, regulating immune responses and maintaining tissue homeostasis. Depending on the microenvironment, macrophages can polarize to two distinct phenotypes. The M1 phenotype is activated by IFN-γ and bacterial products, and displays an inflammatory profile, while M2 macrophages are activated by IL-4 and tend to be anti-inflammatory or immunosupressive. It was observed that DnaK from Mycobacterium tuberculosis has immunosuppressive properties, inducing a tolerogenic phenotype in dendritic cells and MDSCs, contributing to graft acceptance and tumor growth. However, its role in macrophage polarization remains to be elucidated. We asked whether DnaK was able to modulate macrophage phenotype. Murine macrophages, derived from bone marrow, or from the peritoneum, were incubated with DnaK and their phenotype compared to M1 or M2 polarized macrophages. Treatment with DnaK leads macrophages to present higher arginase I activity, IL-10 production and FIZZ1 and Ym1 expression. Furthermore, DnaK increased surface levels of CD206. Importantly, DnaK-treated macrophages were able to promote tumor growth in an allogeneic melanoma model. Our results suggest that DnaK polarizes macrophages to the M2-like phenotype and could constitute a virulence factor and is an important immunomodulator of macrophage responses.

Mesenchymal stem cells from different murine tissues have differential capacity to metabolize extracellular nucleotides.

Mesenchymal stem cells (MSCs) have shown a great potential for cell-based therapy and many different therapeutic purposes. Despite the recent advances in the knowledge of MSCs biology, their biochemical and molecular properties are still poorly defined. Ecto-nucleoside triphosphate diphosphohydrolases (E-NTPDases) and ecto-5'-nucleotidase (eNT/CD73) are widely expressed enzymes that hydrolyze extracellular nucleotides, generating an important cellular signaling cascade. Currently, studies have evidenced the relationship between the purinergic system and the development, maintenance, and differentiation of stem cells. The objective of this study is to identify the NTPDases and eNT/CD73 and compare the levels of nucleotide hydrolysis on MSCs isolated from different murine tissues (bone marrow, lung, vena cava, kidney, pancreas, spleen, skin, and adipose tissue). MSCs from all tissues investigated expressed the ectoenzymes at different levels. In MSCs from pancreas and adipose tissue, the hydrolysis of triphosphonucleosides was significantly higher when compared to the other cells. The diphosphonucleosides were hydrolyzed at a higher rate by MSC from pancreas when compared to MSC from other tissues. The differential nucleotide hydrolysis activity and enzyme expression in these cells suggests that MSCs play different roles in regulating the purinergic system in these tissues. Overall MSCs are an attractive adult-derived cell population for therapies, however, the fact that ecto-nucleotide metabolism can affect the microenvironment, modulating important events, such as immune response, makes the assessment of this metabolism an important part of the characterization of MSCs to be applied therapeutically.

Periodontal disease and high doses of inhaled corticosteroids alter NTPDase activity in the blood serum of rats.

BACKGROUND: Certain drugs such as glucocorticoids may interfere with the modulation of periodontal disease. In contrast, corticosteroid treatment has been associated with a protective effect with regard to periodontal breakdown, depending on the dose, pathway, and exposure time. Considering the potential relevance of nucleotidases in coordinating the cardiovascular system and inflammation processes, the aim of this study was to investigate the nucleotidase activities in the blood serum of rats with periodontal disease exposed chronically to inhaled corticosteroids. METHODS: Adult male Wistar rats (n=26) were randomly assigned to one of the following four study groups: a control group that received no intervention; a periodontal disease group that received saline solution; a 'low dose' group that received 30 µg of budesonide daily; and a corresponding 'high dose' group that received 100 µg daily over a 15-day time course. The hydrolysis of ATP, ADP, and AMP were analysed in blood serum. RESULTS: Periodontal disease diminished the hydrolysis of ATP and enhanced the hydrolysis of ADP. Repeated administration of either a low or high dose in the periodontal disease model of inhaled corticosteroids reversed the observed increase in ADP hydrolysis, and only the repeated administration of low doses of inhaled corticosteroids was able to reverse the decrease in the hydrolysis of ATP induced by periodontal disease. CONCLUSION: The variables investigated in this study may be involved in the pathophysiology of periodontal disease and may participate in the mechanisms that mediate the development of some of the side effects of inhaled corticosteroids.

Boldine induces cell cycle arrest and apoptosis in T24 human bladder cancer cell line via regulation of ERK, AKT, and GSK-3ß.

OBJECTIVE: Bladder cancer is one of the most prevalent genitourinary malignancies. Despite active chemotherapy regimens, patients with bladder cancer suffer from a high rate of tumor recurrence. Thus, new approaches and agents to improve quality of life and survival still need to be developed. The objective of the present study was to evaluate the effect and underlying mechanisms of boldine, an aporphine alkaloid of Peumus boldus, on bladder cancer proliferation and cell death. METHODS: Sulforhodamine B assay, Tetrazolium reduction assay, Flow Cytometry Analysis, Ecto-5'-nucleotidase activity and Western blot assay were performed. RESULTS: The results showed that boldine was able to reduce cell viability and cell proliferation in T24 cells. In addition, boldine arrests the cell cycle at G2/M-phase and cause cell death by apoptosis. Boldine-induced inhibition of cell growth and cell cycle arrest appears to be linked to inactivation of extracellular signal-regulated kinase protein (ERK). Additionally, the efficacy of boldine in apoptosis-induced in T24 cells is correlated with modulation of AKT (inactivation) and glycogen synthase kinase-3ß (GSK-3ß) (activation) proteins. CONCLUSIONS: The present findings may, in part, explain the therapeutic effects of boldine for treatment of urinary bladder cancer.

Resveratrol-loaded lipid-core nanocapsules treatment reduces in vitro and in vivo glioma growth.

The development of novel therapeutic strategies to treat gliomas remains critical as a result of the poor prognoses, inef-. ficient therapies and recurrence associated with these tumors. In this context, biodegradable nanoparticles are emerging as efficient drug delivery systems for the treatment of difficult-to-treat diseases such as brain tumors. In the current study, we evaluated the antiglioma effect of trans-resveratrol-loaded lipid-core nanocapsules (RSV-LNC) based on in vitro (C6 glioma cell line) and in vivo (brain-implanted C6 cells) models of the disease. In vitro, RSV-LNC decreased the viability of C6 glioma cells to a higher extent than resveratrol in solution. Interestingly, RSV-LNC treatment was not cytotoxic to hippocampal organotypic cultures, a model of healthy neural cells, suggesting selectivity for cancer cells. RSV-LNC induced losses in glioma cell viability through induction of apoptotic cell death, as assessed by Annexin-FITC/PI assay, which was preceded by an early arrest in the S and G1 phases of the cell cycle. In brain-implanted C6 tumors, treatment with RSV-LNC (5 mg/kg/day, i.p.) for 10 days promoted a marked decrease in tumor size and also reduced the incidence of some malignant tumor-associated characteristics, such as intratumoral hemorrhaging, intratumoral edema and pseudopalisading, compared to resveratrol in solution. Taken together, the results presented herein suggest that nanoencapsulation of resveratrol improves its antiglioma activity, thus providing a provocative foundation for testing the clinical usefulness of nanoformulations of this natural compound as a new chemotherapeutic strategy for the treatment of gliomas.

The antiproliferative effect of indomethacin-loaded lipid-core nanocapsules in glioma cells is mediated by cell cycle regulation, differentiation, and the inhibition of survival pathways.

Despite recent advances in radiotherapy, chemotherapy, and surgical techniques, glioblastoma multiforme (GBM) prognosis remains dismal. There is an urgent need for new therapeutic strategies. Nanoparticles of biodegradable polymers for anticancer drug delivery have attracted intense interest in recent years because they can provide sustained, controlled, and targeted delivery. Here, we investigate the mechanisms involved in the antiproliferative effect of indomethacin-loaded lipid-core nanocapsules (IndOH-LNC) in glioma cells. IndOH-LNC were able to reduce cell viability by inducing apoptotic cell death in C6 and U138-MG glioma cell lines. Interestingly, IndOH-LNC did not affect the viability of primary astrocytes, suggesting that this formulation selectively targeted transformed cells. Mechanistically, IndOH-LNC induced inhibition of cell growth and cell-cycle arrest to be correlated with the inactivation of AKT and ß-catenin and the activation of GSK-3ß. IndOH-LNC also induced G0/G1 and/or G2/M phase arrest, which was accompanied by a decrease in the levels of cyclin D1, cyclin B1, pRb, and pcdc2 and an increase in the levels of Wee1 CDK inhibitor p21(WAF1). Additionally, IndOH-LNC promoted GBM cell differentiation, observed as upregulation of glial fibrillary acidic protein (GFAP) protein and downregulation of nestin and CD133. Taken together, the crosstalk among antiproliferative effects, cell-cycle arrest, apoptosis, and cell differentiation should be considered when tailoring pharmacological interventions aimed at reducing glioma growth by using formulations with multiples targets, such as IndOH-LNC.

Indomethacin-loaded lipid-core nanocapsules reduce the damage triggered by Aß1-42 in Alzheimer's disease models.

Neuroinflammation, characterized by the accumulation of activated microglia and reactive astrocytes, is believed to modulate the development and/or progression of Alzheimer's disease (AD). Epidemiological studies suggesting that nonsteroidal anti-inflammatory drugs decrease the risk of developing AD have encouraged further studies elucidating the role of inflammation in AD. Nanoparticles have become an important focus of neurotherapeutic research because they are an especially effective form of drug delivery. Here, we investigate the potential protective effect of indomethacin-loaded lipid-core nanocapsules (IndOH-LNCs) against cell damage and neuroinflammation induced by amyloid beta (Aß)1-42 in AD models. Our results show that IndOH-LNCs attenuated Aß-induced cell death and were able to block the neuroinflammation triggered by Aß1-42 in organotypic hippocampal cultures. Additionally, IndOH-LNC treatment was able to increase interleukin-10 release and decrease glial activation and c-jun N-terminal kinase phosphorylation. As a model of Aß-induced neurotoxicity in vivo, animals received a single intracerebroventricular injection of Aß1-42 (1 nmol/site), and 1 day after Aß1-42 infusion, they were administered either free IndOH or IndOH-LNCs (1 mg/kg, intraperitoneally) for 14 days. Only the treatment with IndOH-LNCs significantly attenuated the impairment of this behavior triggered by intracerebroventricular injection of Aß1-42. Further, treatment with IndOH-LNCs was able to block the decreased synaptophysin levels induced by Aß1-42 and suppress glial and microglial activation. These findings might be explained by the increase of IndOH concentration in brain tissue attained using drug-loaded lipid-core NCs. All these findings support the idea that blockage of neuroinflammation triggered by Aß is involved in the neuroprotective effects of IndOH-LNCs. These data provide strong evidence that IndOH-LNC treatment may represent a promising approach for treating AD.

Overexpression of NTPDase2 in gliomas promotes systemic inflammation and pulmonary injury.

Gliomas are the most common and devastating type of primary brain tumor. Many non-neoplastic cells, including immune cells, comprise the tumor microenvironment where they create a milieu that appears to dictate cancer development. ATP and the phosphohydrolytic products ADP and adenosine by activating P2 and P1 receptors may participate in these interactions among malignant and immune cells. Purinergic receptor-mediated cell communication is closely regulated by ectonucleotidases, such as by members of the ectonucleoside triphosphate diphosphohydrolase (E-NTPDase) family, which hydrolyze extracellular nucleotides. We have shown that gliomas, unlike astrocytes, exhibit low NTPDase activity. Furthermore, ATP induces glioma cell proliferation and the co-administration of apyrase decreases progression of injected cells in vivo. We have previously shown that NTPDase2 reconstitution dramatically increases tumor growth in vivo. Here we evaluated whether NTPDase2 reconstitution to gliomas modulates systemic inflammatory responses. We observed that NTPDase2 overexpression modulated pro-inflammatory cytokine production and platelet reactivity. Additionally, pathological alterations in the lungs were observed in rats bearing these tumors. Our results suggest that disruption of purinergic signaling via ADP accumulation creates an inflammatory state that may promote tumor spread and dictate clinical progression.

Effects of restraint stress on the daily rhythm of hydrolysis of adenine nucleotides in rat serum.

BACKGROUND: Adenosine 5-triphosphate (ATP) and its breakdown products ADP and adenosine can act as extracellular messengers in a range of biological processes. Extracellular adenine nucleotides are metabolized by a number of enzymes including NTPDases and 5'-nucleotidase, which are considered to be the major regulators of purinergic signaling in the blood. Previous work by our group demonstrated that ATPase and ADPase activities in rat serum exhibit a 24-h temporal pattern, with higher enzyme activity during the dark (activity) phase. It was found that stress can cause disruptions in biological circadian rhythms and in the cardiovascular system. Therefore, the aim of the present study was to examine the influence of acute stress exposure upon temporal patterns of NTPDase and 5-nucleotidase enzyme activities in rat blood serum. METHODS: Adult male Wistar rats were divided into 4 groups: ZT0, ZT6, ZT12 and ZT18. Each group was subdivided in 4 groups: control, immediately, 6 h and 24 h after one hour of restraint stress. ATP, ADP and AMP hydrolysis were assayed in the serum. RESULTS: All stressed groups showed significant decreases in all enzyme activities at ZT 12 and ZT 18 when compared with control. CONCLUSION: Acute stress provokes a decrease in nucleotidase activities dependent on the time that this stress occurs and this effect appears to persist for at least 24 hours. Stress can change levels of nucleotides, related to increased frequency of cardiovascular events during the activity phase. Altered levels of nucleotides in serum may be involved in cardiovascular events more frequent during the activity phase in mammals, and with their etiology linked to stress.

Ecto-5'-nucleotidase/CD73 knockdown increases cell migration and mRNA level of collagen I in a hepatic stellate cell line.

Ecto-5'-nucleotidase (eNT/CD73, E.C.3.1.3.5) is a glycosyl phosphatidylinositol (GPI)-linked cell-surface protein with several functions, including the local generation of adenosine from AMP, with the consequent activation of adenosine receptors and the salvaging of extracellular nucleotides. It also apparently functions independently of this activity, e.g., in the mediation of cell-cell adhesion. Liver fibrosis can be considered as a dynamic and integrated cellular response to chronic liver injury and the activation of hepatic stellate cells (HSCs) plays a role in the fibrogenic process. eNT/CD73 and adenosine are reported to play an important role in hepatic fibrosis in murine models. Knockdown of eNT/CD73 leads to an increase in mRNA expression of tissue non-specific alkaline phosphatase (TNALP), another AMP-degrading enzyme and thus no alteration is seen in the total ecto-AMPase activity of the cell. eNT/CD73 knockdown also leads to changes in the expression of collagen I and a clear alteration of cell migration. We suggest that eNT/CD73 protein expression controls cell migration and collagen expression in a mechanism independent of changes in nucleotide metabolism.

Protective effects of indomethacin-loaded nanocapsules against oxygen-glucose deprivation in organotypic hippocampal slice cultures: involvement of neuroinflammation.

Targeted treatment of diseases of the central nervous system remains problematic due to the complex pathogenesis of these disorders and the difficulty in drug delivery. Here we investigate the neuroprotective effect of indomethacin-loaded nanocapsules (IndOH-NC) in an in vitro model of ischemia. For this purpose we used organotypic hippocampal cultures exposed to oxygen-glucose deprivation (OGD). When the cultures were exposed to 60 min of OGD, 54.5±14.7% of the total area of the hippocampal slices was labeled with propidium iodide. On the other hand, when the cultures were treated with 50 or 100 µM of IndOH-NC the cell death was significantly reduced to 31±7% (P<0.05) and 20±4% (P<0.001), respectively. The treatment with IndOH-NC markedly inhibited the levels of the pro-inflammatory cytokines IL-1ß, IL-6 and TNF-α levels even 48 h after OGD. Immunoblotting revealed that treatment with 100 µM of IndOH-NC was able to significantly reduce to the levels of control cultures the levels of ERK1/2 and JNK phosphorylation, as well as iNOS activation. Additionally, IndOH-NC prevented glial activation induced by OGD, as evidenced by a decrease of GFAP immunocontent and Isolectin B(4) reactivity. Our results clearly demonstrate that IndOH-NC might represent a promising pharmaceutical neuroprotective formulation for cerebral ischemia, most probably by inhibiting the inflammatory cascades.

Changes in E-NTPDase 3 expression and extracellular nucleotide hydrolysis during the myofibroblast/lipocyte differentiation.

Hepatic stellate cells (HSC) play a critical role in the development and maintenance of liver fibrosis. HSC are lipocytes that displayed the capacity to develop into myofibroblast-like cells. Ecto-nucleoside triphosphate diphosphohydrolases (E-NTPDases) regulate the concentration of extracellular nucleotides, signaling molecules that play a role in the pathogenesis of hepatic fibrosis. In the present study, we identified and compared the expressions of E-NTPDase family members in two different phenotypes of the mouse hepatic stellate cell line (GRX) and evaluated the nucleotide hydrolysis by these cells. We show that both phenotypes of GRX cell line expressed NTPDase 3 and 5. However, only activated cells expressed NTPDase 6. In quiescent-like cells, the hydrolysis of triphosphonucleosides was significantly higher, and was related to an increase in Entpd3 mRNA expression. The diphosphonucleosides were hydrolyzed at a similar rate by two phenotypes of GRX cells. We suggest that up-regulation of Entpd3 mRNA expression modulates the extracellular concentration of nucleotides/nucleosides and affect P2-receptor signaling differently in quiescent-like cells and may play a role in the regulation of HSC functions.

Effect of temozolomide treatment on the adenine nucleotide hydrolysis in blood serum of rats with implanted gliomas

Objective: Adenine nucleotides and adenosine have many important functions in the physiological and pathological conditions. The measurement of these nucleotides in serum may be an auxiliary tool in the identification of cellular damage in many pathological conditions. The aim of this study is to examine the effect of chemotherapy treatment on nucleotide hydrolysis in the serum of rats following glioma implantation. Methods: C6 glioma cells were injected in the right striatum of 60 day-old Wistar rats, and 20 days after the induction of gliomas, blood serum samples were prepared for measurement of ATP and AMP hydrolysis. Results: The pathological analysis showed that the malignant gliomas induced by C6 injection and treated with temozolomide exhibited a reduction in malignant characteristics. The results demonstrated that the rats that underwent temozolomide treatment had a significant decrease (p<0.05) in blood serum hydrolysis of ATP and AMP when compared with the glioma group. None of the animals included in this study presented significant alterations in the activities of the serum enzymes alanine aminotransferase, aspartate aminotransferase, and alkaline phosphatase. Conclusion: The decrease in the enzymatic hydrolysis of the ATP and AMP is probably related to the diminished malignant characteristics caused by temozolomide treatment on the gliomas in vivo.