Promising 2,6,9-Trisubstituted Purine Derivatives for Anticancer Compounds: Synthesis, 3D-QSAR, and Preliminary Biological Assays

We designed, synthesized, and evaluated novel 2,6,9-trisubstituted purine derivatives for their prospective role as antitumor compounds. Using simple and efficient methodologies, 31 compounds were obtained. We tested these compounds in vitro to draw conclusions about their cell toxicity on seven cancer cells lines and one non-neoplastic cell line. Structural requirements for antitumor activity on two different cancer cell lines were analyzed with SAR and 3D-QSAR. The 3D-QSAR models showed that steric properties could better explain the cytotoxicity of compounds than electronic properties (70% and 30% of contribution, respectively). From this analysis, we concluded that an arylpiperazinyl system connected at position 6 of the purine ring is beneficial for cytotoxic activity, while the use of bulky systems at position C-2 of the purine is not favorable. Compound 7h was found to be an effective potential agent when compared with a currently marketed drug, cisplatin, in four out of the seven cancer cell lines tested. Compound 7h showed the highest potency, unprecedented selectivity, and complied with all the Lipinski rules. Finally, it was demonstrated that 7h induced apoptosis and caused cell cycle arrest at the S-phase on HL-60 cells. Our study suggests that substitution in the purine core by arylpiperidine moiety is essential to obtain derivatives with potential anticancer activityFinancial support was received from FONDECYT (Research Grant N◦ 1161816) and FONDEQUIP program CONICYT EQM 160042, Czech Science Foundation (19-09086S) and Palacky University (IGA_PrF_2019_013) and Xunta de Galicia (ED431C 2018/21) and European Regional Development Fund (Project ENOCH, N◦ CZ.02.1.01/0.0/0.0/16_019/0000868)S

Neonatal mesenchymal stem cell treatment improves myelination impaired by global perinatal asphyxia in rats

Indexación ScopusThe effect of perinatal asphyxia (PA) on oligodendrocyte (OL), neuroinflammation, and cell viability was evaluated in telencephalon of rats at postnatal day (P)1, 7, and 14, a period char-acterized by a spur of neuronal networking, evaluating the effect of mesenchymal stem cell (MSCs)- treatment. The issue was investigated with a rat model of global PA, mimicking a clinical risk oc-curring under labor. PA was induced by immersing fetus-containing uterine horns into a water bath for 21 min (AS), using sibling-caesarean-delivered fetuses (CS) as controls. Two hours after delivery, AS and CS neonates were injected with either 5 μL of vehicle (10% plasma) or 5 × 104 MSCs into the lateral ventricle. Samples were assayed for myelin-basic protein (MBP) levels; Olig-1/Olig-2 tran-scriptional factors; Gglial phenotype; neuroinflammation, and delayed cell death. The main effects were observed at P7, including: (i) A decrease of MBP-immunoreactivity in external capsule, corpus callosum, cingulum, but not in fimbriae of hippocampus; (ii) an increase of Olig-1-mRNA levels; (iii) an increase of IL-6-mRNA, but not in protein levels; (iv) an increase in cell death, including OLs; and (v) MSCs treatment prevented the effect of PA on myelination, OLs number, and cell death. The present findings show that PA induces regional- and developmental-dependent changes on myelination and OLs maturation. Neonatal MSCs treatment improves survival of mature OLs and myelination in telencephalic white matter. © 2021 by the authors. Licensee MDPI, Basel, Switzerland.https://www.mdpi.com/1422-0067/22/6/327

Intranasal administration of mesenchymal stem cell secretome reduces hippocampal oxidative stress, neuroinflammation and cell death, improving the behavioral outcome following perinatal asphyxia

Indexación: Scopus.PerinatalAsphyxia (PA) is a leading cause ofmotor and neuropsychiatric disability associated with sustained oxidative stress, neuroinflammation, and cell death, affecting brain development. Based on a rat model of global PA, we investigated the neuroprotective effect of intranasally administered secretome, derived from human adipose mesenchymal stem cells (MSC-S), preconditioned with either deferoxamine (an hypoxia-mimetic) or TNF-ff+IFN- (pro-inflammatory cytokines). PA was generated by immersing fetus-containing uterine horns in a water bath at 37 ffC for 21 min. Thereafter, 16 ffL of MSC-S (containing 6 ffg of protein derived from 2 ff 105 preconditioned-MSC), or vehicle, were intranasally administered 2 h after birth to asphyxia-exposed and control rats, evaluated at postnatal day (P) 7. Alternatively, pups received a dose of either preconditioned MSC-S or vehicle, both at 2 h and P7, and were evaluated at P14, P30, and P60. The preconditioned MSC-S treatment (i) reversed asphyxia-induced oxidative stress in the hippocampus (oxidized/reduced glutathione); (ii) increased antioxidative Nuclear Erythroid 2-Related Factor 2 (NRF2) translocation; (iii) increased NQO1 antioxidant protein; (iv) reduced neuroinflammation (decreasing nuclearNF-ffB/p65 levels and microglial reactivity); (v) decreased cleaved-caspase-3 cell-death; (vi) improved righting reflex, negative geotaxis, cliff aversion, locomotor activity, anxiety, motor coordination, and recognition memory. Overall, the study demonstrates that intranasal administration of preconditioned MSC-S is a novel therapeutic strategy that prevents the long-term effects of perinatal asphyxia. © 2020 by the authors.https://www.mdpi.com/1422-0067/21/20/780

Biologically active alkaloids and a free radical scavenger from Prosopis species

Luis Astudillo, Cristina Theoduloz and Guillermo Schmeda-Hirschmann. Laboratorio de Química de Productos Naturales, Instituto de Química de Recursos Naturales, Universidad de Talca, Casilla 747, Talca, Chile.Abstract The biological activity of extracts from the aerial parts of five Argentinian Prosopis species and the exudate of P. flexuosa were assessed for DNA binding, β-glucosidase inhibition and free radical scavenging effect using the DPPH decoloration assay. DNA binding effect was found mainly in the basic fraction. The alkaloids tryptamine as well as piperidine and phenethylamine derivatives were isolated from the basic extracts. At 0.50 mg/ml, DNA binding activities ranged from 28% for tryptamine to 0–27% for the phenethylamine and 47–54% for the piperidine derivatives. Tryptamine and 2-β-methyl-3-β-hydroxy-6-β-piperidinedodecanol showed a moderate inhibition (27–32%) of the enzyme β-glucosidase at 100 μg/ml. The exudate of P. flexuosa displayed a strong free radical scavenger effect in the DPPH decoloration assay. The main active constituent was identified as catechin

The Long-Term Impairment in Redox Homeostasis Observed in the Hippocampus of Rats Subjected to Global Perinatal Asphyxia (PA) Implies Changes in Glutathione-Dependent Antioxidant Enzymes and TIGAR-Dependent Shift Towards the Pentose Phosphate Pathways: Ef

We have recently reported that global perinatal asphyxia (PA) induces a regionally sustained increase in oxidized glutathione (GSSG) levels and GSSG/GSH ratio, a decrease in tissue-reducing capacity, a decrease in catalase activity, and an increase in apoptotic caspase-3-dependent cell death in rat neonatal brain up to 14 postnatal days, indicating a long-term impairment in redox homeostasis. In the present study, we evaluated whether the increase in GSSG/GSH ratio observed in hippocampus involves changes in glutathione reductase (GR) and glutathione peroxidase (GPx) activity, the enzymes reducing glutathione disulfide (GSSG) and hydroperoxides, respectively, as well as catalase, the enzyme protecting against peroxidation. The study also evaluated whether there is a shift in the metabolism towards the penthose phosphate pathway (PPP), by measuring TIGAR, the TP53-inducible glycolysis and apoptosis regulator, associated with delayed cell death, further monitoring calpain activity, involved in bax-dependent cell death, and XRCC1, a scaffolding protein interacting with genome sentinel proteins. Global PA was induced by immersing fetus-containing uterine horns removed by a cesarean section from on term rat dams into a water bath at 37 °C for 21 min. Asphyxia-exposed and sibling cesarean-delivered fetuses were manually resuscitated and nurtured by surrogate dams. Animals were euthanized at postnatal (P) days 1 or 14, dissecting samples from hippocampus to be assayed for glutathione, GR, GPx (all by spectrophotometry), catalase (Western blots and ELISA), TIGAR (Western blots), calpain (fluorescence), and XRCC1 (Western blots). One hour after delivery, asphyxia-exposed and control neonates were injected with either 100 μl saline or 0.8 mmol/kg nicotinamide, i.p., shown to protect from the short- and long-term consequences of PA. It was found that global PA produced (i) a sustained increase of GSSG levels and GSSG/GSH ratio at P1 and P14; (ii) a decrease of GR, GPx, and catalase activity at P1 and P14; (iii) a decrease at P1, followed by an increase at P14 of TIGAR levels; (iv) an increase of calpain activity at P14; and (v) an increase of XRCC1 levels, but only at P1. (vi) Nicotinamide prevented the effect of PA on GSSG levels and GSSG/GSH ratio, and on GR, GPx, and catalase activity, also on increased TIGAR levels and calpain activity observed at P14. The present study demonstrates that the long-term impaired redox homeostasis observed in the hippocampus of rats subjected to global PA implies changes in GR, GPx, and catalase, and a shift towards PPP, as indicated by an increase of TIGAR levels at P14

Phytostabilization of Cu in mine tailings using native plant Carpobrotus aequilaterus and the addition of potassium humates

Mine tailings are a serious problem in many countries because their deposits cover large soil areas and are an important source of metal trace elements and sulphur. The objective of this study was to evaluate the phytostabilization capacity of metals and sulphur of the Chilean native plant Carpobrotus aequilaterus with the addition of potassium humates solution. Mine tailings presented a slightly acid pH of 6.3 +/- 0.1, electrical conductivity of 3.84 +/- 0.10 dS m-1, extractable S of 2209 +/- 102 mg kg(-1), SO42- of 1243 +/- 27.8 mg L-1 and low contents of N, P and organic matter. Among the trace metals and metalloids (As, Cd, Cr, Mn, Mo, Ni, Pb and Zn), only Cu was found at high levels (1999 +/- 223 mg kg(-1)) in these mine tailings, but the metal availability is low (1.25%). Potassium humates showed a strongly alkaline pH, conditions that favour the formation of stable dissolved metal humates. The plant was cultivated in pots containing mine tailings (control) and mine tailings with the addition of potassium humates at doses of 30 and 60 kg ha-1 dissolved in irrigation water. The plants were adapted to this substrate with low fertility and high levels of SO4 (2-). At 120 days of cultivation, plants mine tailings containing 60 kg ha(-1) of potassium humates showed significantly higher concentrations in aerial part of Cu and Fe (29.3 +/- 7.5 mg kg(-1) and 546 +/- 181 mg kg(-1), respectively), than control. The concentration of Mn, S and Zn in the plant was not affected by the application of potassium humates. However, the plant showed accumulation capacity of Mn in leaves (930 +/- 255 mg kg(-1)). Except for Fe and Mn, the concentrations of metal in this plant do not exceed the levels of metals considered sufficient or normal indicating a low metal availability in these mine tailings. With the addition of potassium humates, the rate of transport to the aerial part of the plant was lower for Cu, indicating that the species increased the absorption of this metal preferentially in the roots, which is favourable for phytostabilization

Lower Jurassic deformation in the eastern Huincul High, Argentina

Subsurface characterization of the structure and sedimentary sequences in the Agua del Cajón area was performed to understand the Lower Jurassic deformation across the eastern Huincul High. Integration of seismic, well data, and fossil fauna allowed establishing the Late Triassic rifting and Jurassic compressional evolution underwent for this area. Four Late Triassic - Early Jurassic extensional depocenters were recognized, being the most significant the Agua del Cajón and El Salitral depocenters. In general, all of them present an E-W to WNW-ESE orientation and are flanked by NNE to NE-trend transfer zones. The contractional structural style of the Agua del Cajón area consists of south-vergence reverse faults and folds with two primary trends: (i) E-W to WNW-ESE and (ii) NE-SW to NNE-SSW. According to the slip and uplift amount, the first-order structural feature in the study area corresponds to the S-verging, E-W Huincul fault. Geometries and patterns in the seismic reflectors evidence two compressional episodes from late early Toarcian to Callovian time. The first one is associated with the inversion of the previous master normal fault of the El Salitral and Agua del Cajón depocenters during the late early Toarcian. The inversion of the NE-SW synthetic normal fault associated with the El Salitral depocenter also occurred during the first deformation pulses favored by its perpendicular orientation to NW-SE Jurassic σ1. NE-SW fault associated with the Agua del Cajon inversion shows no evidence of inversion-related deformation mechanisms. Instead, the formation of this structure is related to the previous NE-SW transfer zone. After a tectonic quiescence period in late Toarcian – late Aalenian, the compressional activity continued during the late Aalenian and Bajocian evidenced by progressive unconformities into Jurassic sequences. This activity would have continued until Callovian times. These results are in agreement with previously reported evolution in the eastern-central Huincul High region. However, they indicate that the contractional intraplate deformation in the southern Neuquén basin would have begun during the late early Toarcian; this is older than previously proposed.Fil: Guzman, Cecilia Griselda. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Ciudad Universitaria. Instituto de Estudios Andinos "Don Pablo Groeber". Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales. Instituto de Estudios Andinos "Don Pablo Groeber"; Argentina. Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales. Departamento de Geología; ArgentinaFil: Tapia, Felipe. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Ciudad Universitaria. Instituto de Estudios Andinos "Don Pablo Groeber". Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales. Instituto de Estudios Andinos "Don Pablo Groeber"; Argentina. Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales. Departamento de Geología; ArgentinaFil: Ambrosio, A.. No especifíca;Fil: Gutierrez Pleimling, A.. No especifíca;Fil: Bustos, G.. No especifíca;Fil: Gómez, C.. No especifíca;Fil: González, J.M.. No especifíca

Hydrogen production by a mixed photoheterotrophic culture: Correlation between gene expression analysis and physiological behavior

Photoheterotrophic bacteria use mechanisms such as H production, carbon dioxide fixation, and the polyhydroxybutyrate (PHB) synthesis to maintain redox balance. Therefore, these aspects must be studied from a metabolic and genomic perspective to optimize the H production. In this study, six genes (nifH, hupS, hoxA, nuoF, phbC and depA) in a photoheterotrophic mixed culture, whose predominant population was Rhodopseudomonas palustris, were studied. The transcriptional activity of the genes was determined by quantitative-PCR under two different conditions: H production and PHB accumulation. Differences in the genes expression level were found compared to those reported in pure strains. The high expression of the nuoF gene during H production, suggest that this is a key enzyme to regulate the reducing power, and it was correlated with a high H yield (3.4 mol H/mol acetate). This last aspect is also explained by the low expression of the uptake hydrogenase gene, hupS

Vulnerability to a metabolic challenge following perinatal asphyxia evaluated by organotypic cultures: neonatal nicotinamide treatment

The hypothesis of enhanced vulnerability following perinatal asphyxia was investigated with a protocol combining in vivo and in vitro experiments. Asphyxia-exposed (AS) (by 21 min water immersion of foetuses containing uterine horns) and caesarean-delivered control (CS) rat neonates were used at P2-3 for preparing triple organotypic cultures (substantia nigra, neostriatum and neocortex). At DIV 18, cultures were exposed to different concentrations of H2O2 (0.25-45 mM), added to the culture medium for 18 h. After a 48-h recovery period, the cultures were either assessed for cell viability or for neurochemical phenotype by confocal microscopy. Energy metabolism (ADP/ATP ratio), oxidative stress (GSH/GSSG) and a modified ferric reducing/antioxidant power assay were applied to homogenates of parallel culture series. In CS cultures, the number of dying cells was similar in substantia nigra, neostriatum and neocortex, but it was several times increased in AS cultures evaluated under the same conditions. A H2O2 challenge led to a concentration-dependent increase in cell death (> fourfold after 0.25 mM of H2O2) in CS cultures. In AS cultures, a significant increase in cell death was only observed after 0.5 mM of H2O2. At higher than 1 mM of H2O2 (up to 45 mM), cell death increased several times in all cultures, but the effect was still more prominent in CS than in AS cultures. The cell phenotype of dying/alive cells was investigated in formalin-fixed cultures exposed to 0 or 1 mM of H2O2, co-labelling for TUNEL (apoptosis), MAP-2 (neuronal phenotype), GFAP (astroglial phenotype) and TH (tyrosine hydroxylase; for dopamine phenotype), counterstaining for DAPI (nuclear staining), also evaluating the effect of a single dose of nicotinamide (0.8 nmol/kg, i.p. injected in 100 mu L, 60 min after delivery). Perinatal asphyxia produced a significant increase in the number of DAPI/TUNEL cells/mm(3), in substantia nigra and neostriatum. One millimolar of H(2)0(2) increased the number of DAPI/TUNEL cells/mm(3) by aetwofold in all regions of CS and AS cultures, an effect that was prevented by neonatal nicotinamide treatment. In substantia nigra, the number of MAP-2/TH-positive cells/mm(3) was decreased in AS compared to CS cultures, also by 1 mM of H(2)0(2), both in CS and AS cultures, prevented by nicotinamide. In agreement, the number of MAP-2/TUNEL-positive cells/mm(3) was increased by 1 mM H2O2, both in CS (twofold) and AS (threefold) cultures, prevented by nicotinamide. The number of MAP-2/TH/TUNEL-positive cells/mm(3) was only increased in CS (> threefold), but not in AS (1.3-fold) cultures. No TH labelling was observed in neostriatum, but 1 mM of H2O2 produced a strong increase in the number of MAP-2/TUNEL-positive cells/mm(3), both in CS (> 2.9-fold) and AS (> fourfold), decreased by nicotinamide. In neocortex, H2O2 increased the number of MAP-2/TUNEL-positive cells/mm(3), both in CS and AS cultures (aethreefold), decreased by nicotinamide. The ADP/ATP ratio was increased in AS culture homogenates (> sixfold), compared to CS homogenates, increased by 1 mM of H(2)0(2), both in CS and AS homogenates. The GSH/GSSG ratio was significantly decreased in AS, compared to CS cultures. One millimolar of H2O2 decreased that ratio in CS and AS homogenates. The present results demonstrate that perinatal asphyxia induces long-term changes in metabolic pathways related to energy and oxidative stress, priming cell vulnerability with both neuronal and glial phenotype. The observed effects were region dependent, being the substantia nigra particularly prone to cell death. Nicotinamide administration in vivo prevented the deleterious effects observed after perinatal asphyxia in vitro, a suitable pharmacological strategy against the deleterious consequences of perinatal asphyxia.FONDECYT-Chile Millenium Institute Initiative BNI P09-015-F MHMarschitz Foundation, Swede