Aurelianolides from Aureliana fasciculata var. fasciculata Trigger Apoptosis With Caspase Activation in Human Leukemia Cells.

BACKGROUND/AIM: Aurelianolide A and B were identified and isolated from Aureliana fasciculata var. fasciculata leaves. Withanolides are naturally occurring C-28 steroidal lactone triterpenoids with cytotoxic and anticancer properties, among other relevant pharmacological activities. Herein we have described, for the first time, the cytotoxic effects of aurelianolides on human cancer cells. MATERIALS AND METHODS: Aurelianolide A and B were tested on human leukemia cell lines: THP-1, MOLT-4, Jurkat, K562 and K562-Lucena 1. RESULTS: For aurelianolide A, MOLT-4 had the lower IC50 (1.17 µM) and for aurelianolide B, Jurkat was the most susceptible cell line (IC50 2.25 µM). On the other hand, the multidrug resistant (MDR) cell line K562-Lucena 1 showed higher IC50 for both aurelianolides. Using 293T, a non-tumor embryonic kidney cell line, we observed an excellent selectivity index for both aurelianolides, from 2.24 (aurelianolide B in K562-Lucena 1) to 45.5 (aurelianolide A in MOLT-4). Aurelianolide A and B activated caspase 3/7 with consequent induction of apoptosis on Jurkat and K562-Lucena 1 cell lines. We have not observed induction of necrosis. CONCLUSION: Aurelianolides A and B have important cytotoxic effects on human leukemia cell lines by the activation of the caspase pathway.

The promising drugs included in WHO's Solidarity Project: a choice based in scientific knowledge and institutional competencies.

BACKGROUND: In March 2020, the World Health Organization (WHO) launched the Solidarity Program, probably the largest global initiative to encourage and support research in four promising drugs, named Remdesivir, Hydroxychloroquine, ß Interferon and the combination Lopinavir / Ritonavir, to reduce the mortality of Coronavirus disease 2019 (COVID-19). OBJECTIVES: Considering the potential impact of Solidarity Program to restrain the current pandemic, the present study aims to investigate whether it was designed upon indicators of scientific productivity, defined as the level of the production of new scientific knowledge and of the institutional capabilities, estimated in terms of scientific publications and technological agreements. METHODS: The scientific documents on Alphacoronavirus, Betacoronavirus, Gammacoronavirus and Coronavirus were retrieved from Scopus database while the technological agreements on coronavirus were obtained through Cortellis. As for the institutions and countries, we have considered the data on author's affiliations in both set of data. For comparison, we included the analysis of documents related with other drugs or therapies, such as vaccines and antibodies, which were listed in a Clarivate's report on coronaviruses research. FINDINGS: Most of the analysis refers to documents on Coronavirus, the largest group. The number of documents related to WHO's drugs are almost five times higher than in the other groups. This subset of documents involves the largest and most diverse number of institutions and countries. As for agreements, we observed a smaller number of institutions involved in it, suggesting differences between countries in terms of technical and human capabilities to develop basic and/or clinical research on coronavirus and to develop new forms or products to treat or to prevent the disease. MAIN CONCLUSIONS: Hence, the results shown in this study illustrate that decisions taken by an international scientific body, as WHO, were mainly based in scientific knowledge and institutional competencies.

The promising drugs included in WHO's Solidarity Project: a choice based in scientific knowledge and institutional competencies

BACKGROUND In March 2020, the World Health Organization (WHO) launched the Solidarity Program, probably the largest global initiative to encourage and support research in four promising drugs, named Remdesivir, Hydroxychloroquine, β Interferon and the combination Lopinavir / Ritonavir, to reduce the mortality of Coronavirus disease 2019 (COVID-19). OBJECTIVES Considering the potential impact of Solidarity Program to restrain the current pandemic, the present study aims to investigate whether it was designed upon indicators of scientific productivity, defined as the level of the production of new scientific knowledge and of the institutional capabilities, estimated in terms of scientific publications and technological agreements. METHODS The scientific documents on Alphacoronavirus, Betacoronavirus, Gammacoronavirus and Coronavirus were retrieved from Scopus database while the technological agreements on coronavirus were obtained through Cortellis. As for the institutions and countries, we have considered the data on author's affiliations in both set of data. For comparison, we included the analysis of documents related with other drugs or therapies, such as vaccines and antibodies, which were listed in a Clarivate's report on coronaviruses research. FINDINGS Most of the analysis refers to documents on Coronavirus, the largest group. The number of documents related to WHO's drugs are almost five times higher than in the other groups. This subset of documents involves the largest and most diverse number of institutions and countries. As for agreements, we observed a smaller number of institutions involved in it, suggesting differences between countries in terms of technical and human capabilities to develop basic and/or clinical research on coronavirus and to develop new forms or products to treat or to prevent the disease. MAIN CONCLUSIONS Hence, the results shown in this study illustrate that decisions taken by an international scientific body, as WHO, were mainly based in scientific knowledge and institutional competencies.

Expression, purification, and characterization of asparaginase II from Saccharomyces cerevisiae in Escherichia coli.

l-asparaginase catalyzes the conversion of l-asparagine to l-aspartate and ammonium. This protein is an important therapeutic enzyme used for the treatment of acute lymphoblastic leukemia. In this study, the asparaginase II-encoding gene ASP3 from Saccharomyces cerevisiae was cloned into the expression vector pET28a in-fusion with a 6x histidine tag and was expressed in Escherichia coli BL21 (DE3) cells. The protein was expressed at a high level (225.6 IU/g cells) as an intracellular and soluble molecule and was purified from the supernatant by nickel affinity chromatography. The enzyme showed very low activity against l-glutamine. The denaturing electrophoresis analysis indicated that the recombinant protein had a molecular mass of ∼38 kDa. The native enzyme was a tetramer with a molecular mass of approximately 178 kDa. The enzyme preparation showed antitumor activity against the K562 and Jurkat cell lines comparable or even superior to the E. coli commercial asparaginase.

An essential role for mast cells as modulators of neutrophils influx in collagen-induced arthritis in the mouse.

Mast cells are involved in immune disorders so that many of the proinflammatory and tissue destructive mediators produced by these cells have been implicated in the pathogenesis of rheumatoid arthritis. This scenario prompted us to investigate the correlation between mast cell degranulation and neutrophil influx within the digits and knees joints of arthritic mice assessing what could be the functional role(s) of joint mast cells in the response to collagen immunization. DBA/1J mice were submitted to collagen-induced arthritis and disease was assessed on day 21, 32 and 42 post-immunization. Pharmacological treatment with the glucocorticoid prednisolone, commonly used in the clinic, and nedocromil, a mast cell stabilizer, was performed from day 21 to 30. Arthritis develop after immunization, gradually increased up to day 42. Neutrophil infiltration peaked on day 32 and 21, in the digits and knees, respectively, showing an unequal pattern of recruitment between these tissues. This difference emerged for mast cells: they peaked in the digits on day 21, but a higher degree of degranulation could be measured in the knee joints. Uneven modulation of arthritis occurred after treatment of mice with prednisolone or nedocromil. Neutrophils migration to the tissue was reduced after both therapies, but only prednisolone augmented mast cell migration to the joints. Nedocromil exerted inhibitory properties both on mast cell proliferation and migration, more effectively on the digit joints. Thus, collagen induced an inflammatory process characterized by tissue mast cells activation and degranulation, suggesting a potential driving force in propagating inflammatory circuits yielding recruitment of neutrophils. However, the different degree of affected joint involvement suggests a time-related implication of digits and knees during collagen-induced arthritis development. These results provide evidence for local alterations whereby mast cells contribute to the initiation of inflammatory arthritis and may be targeted in intervention strategies.

An in vitro model for dengue virus infection that exhibits human monocyte infection, multiple cytokine production and dexamethasone immunomodulation

An important cytokine role in dengue fever pathogenesis has been described. These molecules can be associated with haemorrhagic manifestations, coagulation disorders, hypotension and shock, all symptoms implicated in vascular permeability and disease worsening conditions. Several immunological diseases have been treated by cytokine modulation and dexamethasone is utilized clinically to treat pathologies with inflammatory and autoimmune ethiologies. We established an in vitro model with human monocytes infected by dengue virus-2 for evaluating immunomodulatory and antiviral activities of potential pharmaceutical products. Flow cytometry analysis demonstrated significant dengue antigen detection in target cells two days after infection. TNF-alpha, IFN-alpha, IL-6 and IL-10 are produced by in vitro infected monocytes and are significantly detected in cell culture supernatants by multiplex microbead immunoassay. Dexamethasone action was tested for the first time for its modulation in dengue infection, presenting optimistic results in both decreasing cell infection rates and inhibiting TNF-alpha, IFN-alpha and IL-10 production. This model is proposed for novel drug trials yet to be applyed for dengue fever.

An in vitro model for dengue virus infection that exhibits human monocyte infection, multiple cytokine production and dexamethasone immunomodulation.

An important cytokine role in dengue fever pathogenesis has been described. These molecules can be associated with haemorrhagic manifestations, coagulation disorders, hypotension and shock, all symptoms implicated in vascular permeability and disease worsening conditions. Several immunological diseases have been treated by cytokine modulation and dexamethasone is utilized clinically to treat pathologies with inflammatory and autoimmune etiologies. We established an in vitro model with human monocytes infected by dengue virus-2 for evaluating immunomodulatory and antiviral activities of potential pharmaceutical products. Flow cytometry analysis demonstrated significant dengue antigen detection in target cells two days after infection. TNF-alpha, IFN-alpha, IL-6 and IL-10 are produced by in vitro infected monocytes and are significantly detected in cell culture supernatants by multiplex microbead immunoassay. Dexamethasone action was tested for the first time for its modulation in dengue infection, presenting optimistic results in both decreasing cell infection rates and inhibiting TNF-alpha, IFN-alpha and IL-10 production. This model is proposed for novel drug trials yet to be applied for dengue fever.

Activation of human T lymphocytes via integrin signaling induced by RGD-disintegrins.

Adhesive interactions play important roles in coordinating T cell migration and activation, which are mediated by binding of integrins to RGD motif found on extracellular matrix proteins. Disintegrins, isolated from snake venoms, contain the RGD sequence that confers selectivity to integrin interaction. We have investigated the ability of three RGD-disintegrins, ligands of alpha(5)beta(1) and alpha(v)beta(3), Flavoridin (Fl), Kistrin (Kr) and Echistatin (Ech), in modulating the activation of human T lymphocyte. The disintegrins induced T cell proliferation and CD69 expression. This activation parallels with actin cytoskeleton reorganization and tyrosine phosphorylation. Furthermore, the peptides induced focal adhesion kinase (FAK) and phosphoinositide 3-kinase (PI3K) activation. Finally, RGD-disintegrins were capable of driving NF-kappaB nuclear translocation and c-Fos expression, in a PI3K and ERK1/2 activities dependent manner. This report is the first to show that RGD-disintegrins interact with integrins on human T lymphocyte surface, modulating cell proliferation and activation of specific pathways coupled to integrin receptor.

NADPH oxidase-derived ROS: key modulators of heme-induced mitochondrial stability in human neutrophils.

Heme is a proinflammatory molecule able to cause a profound delay of constitutive apoptosis of human neutrophils, an effect that likely contributes to chronic inflammation associated with hemolytic diseases. Herein we show that heme-induced delay of neutrophil apoptosis correlates with the prevention of mitochondrial potential (Deltapsi(m)) dissipation by a mechanism dependent on NADPH oxidase (NADPHox)-generated reactive oxygen species (ROS) and NF-kappaB. Deltapsi(m) maintenance is accompanied by inhibition of Bax insertion into mitochondria and by a decrease in the Bad/Bcl-X(L) ratio. Heme induces Bad degradation in a completely ROS-dependent manner, as well as Bcl-X(L) synthesis, a phenomenon that also requires NF-kappaB activation. These data indicate that heme-induced preservation of mitochondrial integrity is a critical checkpoint controlled by NADPH oxidase generated-ROS and redox-sensitive NF-kappaB activation.

Involvement of phosphatidylinositol-3 kinase-Akt and nuclear factor kappa-B pathways in the effect of frutalin on human lymphocyte.

The mechanisms involved in the mitogenic effect of lectins are not fully understood and are thought to involve a cascade of intracellular signals related to T cell receptor activation. This study shows that frutalin, the alpha-D-galactose-binding lectin from Artocarpus incisa seeds, is a potent mitogenic activator of human lymphocytes. This effect is inhibited by D-galactose and PI3K inhibitors, and is accompanied by an increase in IL-2 receptor expression and by a PI3K-dependent IL-2 gene expression and IL-2 protein synthesis. Frutalin also induces Akt-phosphorylation and activates NF-kappaB, inducing its translocation from the cytosol to the nucleus. Both effects are blocked in the presence of D-galactose or by PI3K inhibitors. In summary, frutalin, interacting with alpha-D-galactose, activates signaling pathways related to TCR, and thereby triggers PI3K/Akt and NF-kappaB pathway, which modulates T cell proliferation, IL-2 synthesis and IL-2R expression. Frutalin might be a useful tool to study intracellular mechanisms following T cell activation that link upstream signaling pathways to downstream events.