Belén Rubio-Ruiz

The Mechanism of Allosteric Coupling in Choline Kinase α1 Revealed by the Action of a Rationally Designed Inhibitor

Applying a CHOK hold: Combined experimental and computational studies of the binding mode of a rationally designed inhibitor of the dimeric choline kinase α1 (CHOKα1) explain the molecular mechanism of negative cooperativity (see scheme) and how the monomers are connected. The results give insight into how the symmetry of the dimer can be partially conserved despite a lack of conservation in the static crystal structures.

Lysophosphatidylcholine Regulates Sexual Stage Differentiation in the Human Malaria Parasite Plasmodium falciparum

Summary Transmission represents a population bottleneck in the Plasmodium life cycle and a key intervention target of ongoing efforts to eradicate malaria. Sexual differentiation is essential for this process, as only sexual parasites, called gametocytes, are infective to the mosquito vector. Gametocyte production rates vary depending on environmental conditions, but external stimuli remain obscure. Here, we show that the host-derived lipid lysophosphatidylcholine (LysoPC) controls P. falciparum cell fate by repressing parasite sexual differentiation. We demonstrate that exogenous LysoPC drives biosynthesis of the essential membrane component phosphatidylcholine. LysoPC restriction induces a compensatory response, linking parasite metabolism to the activation of sexual-stage-specific transcription and gametocyte formation. Our results reveal that malaria parasites can sense and process host-derived physiological signals to regulate differentiation. These data close a critical knowledge gap in parasite biology and introduce a major component of the sexual differentiation pathway in Plasmodium that may provide new approaches for blocking malaria transmission.

Effects of Indomethacin, Nimesulide, and Diclofenac on Human MG-63 Osteosarcoma Cell Line

Nonsteroidal anti-inflammatory drugs (NSAIDs) are among the most widely prescribed drugs worldwide and serve as treatment of some degenerative inflammatory joint diseases. The aim of the present study was to investigate the influence of different concentrations of three NSAIDs on cell proliferation, differentiation, antigenic profile, and cell cycle in the human MG-63 osteosarcoma cell line, incubated for 24 hr. All NSAIDs had an inhibiting effect on osteoblastic proliferation. Treatments for 24 hr had small but significant effects on the antigenic profile. No treatment altered osteocalcin synthesis. Indomethacin and nimesulide treatments arrested the cell cycle at G0/G1. These results suggest that indomethacin, nimesulide, and diclofenac appear to have no effects on osteocalcin synthesis and a slight effect on the antigenic profile. They may delay bone regeneration due to their inhibiting effect on osteoblast growth. Therefore, these drugs should only be used in situations that do not require rapid bone healing.

Effect of acetaminophen (paracetamol) on human osteosarcoma cell line MG63

AbstractAim:To examine the effects of acetaminophen (paracetamol), a nonsteroidal anti-inflammatory drug (NSAID), on different cellular and functional parameters of the human osteosarcoma cell line MG63.Methods:Flow cytometry was used to study proliferation, antigenic profile, and phagocytic activity, and radioimmunoassay was used to determine osteocalcin synthesis as a cell differentiation marker.Results:Short-term treatment with therapeutic doses of paracetamol(5 or 25 μmol/L) reduced cell proliferation, osteocalcin synthesis, and phagocyte activity, and increased the expression of antigens involved in antigen presentation to T lymphocytes (CD80, CD86, HLA-DR).Conclusion:These findings suggest that paracetamol activates the osteoblast, inducing its immunogenic action to the detriment of its bone formation capacity.

Determination of Potential Scaffolds for Human Choline Kinase α1 by Chemical Deconvolution Studies

Dual binding modes: Combined empirical and computational studies of a series of compounds showed adenine and 1-benzyl-4-(dimethylamino)pyridinium fragments to function most efficiently in binding CHOKα1, and also determined how the latter fragment interacts with the choline binding site through two different binding modes. These data provide a basis for the future design of better and more selective inhibitors.

Antiproliferative Activity, Cell Cycle, and Apoptosis Studies of a Series of 6-Substituted 9H-Purin-9-yl-pyridinium Derivatives on a Human Cervical Carcinoma Cell Line

Physicochemical parameters are among the most relevant properties to be evaluated in the early phase of drug development. Lipophilicity is one physicochemical parameter for which early prescreening is available. Correlation analysis between lipophilicity and such biological activities as cytotoxicity, antiproliferative effects, and apoptosis has a significant impact on drug discovery, as it can be used to predict and estimate biological efficacy. Choline kinase (ChoK) is overexpressed in human tumors. Small-molecule inhibitors that can interfere with ChoK activity have proven to be effective antitumor drugs in vitro and in vivo. We recently reported the rational development of a series of nonsymmetrical ChoK inhibitors bearing a 4-substituted pyridinium ring and an adenine moiety connected by linkers of various lengths (Figure 1, compounds 1–8). These structures were biologically evaluated and showed moderate potency as antiproliferative agents against the human hepatoma HepG2 cell line. Considering that lipophilicity can be easily modified and determined by characterizing molecules prepared with different moieties, herein we present a new series of compounds in which the polar amino group at position 6 of the adenine (Figure 1, compounds 1–8, X=NH2) was replaced with a benzylthio substituent (Figure 1, compounds 9–16, X=SCH2Ph) to increase their lipophilicity. The antiproliferative and cytotoxic effects of compounds 1–16 were evaluated against a human cervical carcinoma (HeLa) cell line to study how lipophilicity influences biological activity. Oncogenic transformations lead to cell-cycle aberration and dysregulation of apoptosis. The targeting of cell-cycle and apoptotic pathways has emerged as an attractive approach for the treatment of cancer. In this study we evaluated the effect of compounds 9–16 on cell-cycle progression and apoptosis in HeLa cells. Finally, the most apoptotic compound, 12, was selected for further investigations of downstream apoptotic signaling by analyzing the activation of caspase-3. Synthesis of the target compounds 9–16 was carried out as shown in Scheme 1. 6-Benzylthiopurine (17) was synthesized by a nucleophilic substitution reaction between benzyl bromide and 6-mercaptopurine. The strategy for synthesizing monocationic intermediates 18–25 was based on our previous reported method. Finally, the purine alkylation at N9 was carried out by microwave-assisted synthesis with DMF as a solvent, irradiating at 130 8C for 30 min. Carcinoma of the cervix is considered to be relatively resistant to chemotherapy. Few cytotoxic agents have shown significant activity in advanced and recurrent cervical cancer. Thus, the effects on cell proliferation were investigated in HeLa cells using the 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyl tetrazolium bromide (MTT) viability assay. Table 1 lists the IC50 values of Figure 1. Structures of monoquaternary pyridinium salts 1–16.

Has catechol-O-methyltransferase genotype (Val158Met) an influence on endocrine, sympathetic nervous and humoral immune systems in women with fibromyalgia syndrome?

Objective:Stress can play an important role in etiology of fibromyalgia syndrome (FMS) by activating the hypothalamic-pituitary-adrenal (HPA) axis, the sympathetic nervous system (SNS), and altering the immune system. The current study examined the influence of catechol-O-methyltransferase (COMT) Val158Met genotypes on salivary markers of HPA axis (cortisol), SNS (&agr;-amylase), and immune (IgA) systems in women with FMS. Methods:Seventy-six women with FMS diagnosed according to the American College of Rheumatology criteria participated in the study. Salivary cortisol, &agr;-amylase activity, salivary flow rate, and IgA concentration were collected from nonstimulated saliva. A numerical pain rate scale (0 to 10) was used to assess the intensity of pain, whereas functional ability was determined using the Fibromyalgia Impact Questionnaire (FIQ). After amplifying Val158Met polymorphisms by polymerase chain reaction, 3 COMT genotypes were considered: Val/Val, Val/Met, and Met/Met. Results:Women with FMS with the Met/Met genotype reported higher &agr;-amylase activity, lower salivary flow rate, and lower IgA concentration than those women with FMS carrying the Val/Met (P<0.05) or Val/Val (P<0.01) genotypes. No difference in cortisol concentration (P>0.70) was found. These results were not associated with the intensity of pain, disability, and medication intake. Conclusions:The results suggest that women with FMS with the Met/Met genotype exhibit greater disturbed activity of the SNS and humoral immune system. These results provide initial evidence of a link between Val158Met polymorphism and dysfunctions in the SNS and humoral immune system in women with FMS.

1H and 13C NMR spectral assignments of pyridinium salts linked to a N‐9 or N‐3 adenine moiety

1H and 13 C NMR spectral data of 13 new compounds containing a 4‐(dimethylamino)‐ or 4‐(pyrrolidin‐1‐yl)pyridinium moiety linked to the N‐9 or N‐3 nitrogen atom of an adenine moiety were assigned. 1D and 2D NMR experiments (DEPT, HSQC and HMBC) allowed the unequivocal identification of N‐9 and N‐3 isomers. Copyright

Influence of Gender in the Psychoneuroimmunological Response to Therapeutic Interval Exercise

Interval exercise has been used as an alternative modality to continuous exercise in patients with various conditions. Although interval exercise can improve health status, it may also exert deleterious effects. Few data are available on differences in psychoneuroimmunological response to high-intensity interval exercise, and it is not known whether males and females differ in their responses to a similar physical stress task. The aim of this study was to evaluate the differences between the psychoneuroimmunological responses of healthy active males and females to a high-intensity interval exercise protocol. Fifty healthy active subjects (25 females) underwent 2 exercise protocol sessions at least 2 weeks apart and at the same time of the day. The first session familiarized participants with the protocol. In the second, after a baseline measurement, subjects performed an exercise protocol with a standardized warm-up followed by three 30-s Wingate tests and an active recovery period. Baseline and postintervention data were gathered on the following: Holter electrocardiogram recordings (standard deviation of normal-to-normal interval [SDNN], square root of mean squared differences of successive NN intervals [RMSSD]); heart rate variability (HRV) index; salivary total protein and immunoglobulin A levels; pressure pain thresholds in masseter and upper trapezius muscles; and profile of mood states. After the exercise protocol, mood disturbance was significantly greater in the males than in the females, while the salivary immunoglobulin A level relative to total proteins was significantly lower in the males. These results suggest that high-intensity interval exercise induces a worse psychoneuroimmunological state in males than in females.

Choline kinase inhibition and docking studies of a series of 6-(benzylthio)-9 H -purin-9-yl-pyridinium derivatives

Human choline kinase is a well validated target for the treatment of cancer. In the last two decades, many choline kinase inhibitors have been developed and one of them is currently under evaluation in clinical trials. In this paper a series of 6-(benzylthio)-9H-purin-9-yl-pyridinium derivatives were evaluated as choline kinase inhibitors, and their effects on cell proliferation were also investigated in the human hepatoma HepG2 cell line. The most potent inhibitor against purified choline kinase-α1 presents an IC50 value of 0.4 μM. The biological data and the docking studies described here, support that the 4-(dimethylamino)pyridinium cationic head and a small linker (benzene or biphenyl) are the essential structural parameters for choline kinase inhibition of the tested compounds.