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http://hdl.handle.net/2445/13750
2024-03-19T11:41:54ZEvaluation of the Ability of PAMPA Membranes to Emulate Biological Processes through the Abraham Solvation Parameter Model
http://hdl.handle.net/2445/208414
Title: Evaluation of the Ability of PAMPA Membranes to Emulate Biological Processes through the Abraham Solvation Parameter Model
Author: Soriano-Meseguer, Sara; Fuguet i Jordà, Elisabet; Port, Adriana; Rosés Pascual, Martí
Abstract: Two parallel artificial membrane permeability assay (PAMPA) systems intended for emulating skin permeability have been characterized through the solvation parameter model of Abraham using multilinear regression analysis. The coefficients of the obtained equations have been compared to the ones already established for other PAMPA membranes using statistical tools. The results indicate that both skin membranes are similar to each other in their physicochemical properties. However, they are different from other PAMPA membranes (e.g., intestinal absorption and blood– brain PAMPAs), mainly in terms of hydrophobicity and hydrogen bonding properties. Next, all PAMPA membranes have been compared to relevant biological processes also characterized through the solvation parameter model. The results highlight that skin-PAMPA membranes are a very good choice to emulate skin permeability.2024-03-05T18:46:15ZMitofusin-2 induced by exercise modifies lipid droplet-mitochondria communication, promoting fatty acid oxidation in male mice with NAFLD
http://hdl.handle.net/2445/208067
Title: Mitofusin-2 induced by exercise modifies lipid droplet-mitochondria communication, promoting fatty acid oxidation in male mice with NAFLD
Author: Bórquez, Juan Carlos; Díaz-Castro, Francisco; Pino-de La Fuente, Francisco; Espinoza, Karla; Figueroa, Ana María; Martínez-Ruiz, Inma; Hernández, Vanessa; López-Soldado, Iiana; Ventura, Raúl; Domingo i Pedrol, Joan Carles; Bosch i Rodríguez, Marta; Fajardo, Alba; Sebastián Muñoz, David; Espinosa, Alejandra; Pol i Sorolla, Albert; Zorzano Olarte, Antonio; Cortés, Víctor; Hernández-Alvarez, María Isabel; Troncoso, Rodrigo
Abstract: Background and aim: The excessive accumulation of lipid droplets (LDs) is a defining characteristic of nonalcoholic fatty liver disease (NAFLD). The interaction between LDs and mitochondria is functionally important for lipid metabolism homeostasis. Exercise improves NAFLD, but it is not known if it has an effect on hepatic LD-mitochondria interactions. Here, we investigated the influence of exercise on LD-mitochondria interactions and its significance in the context of NAFLD. Approach and results: Mice were fed high-fat diet (HFD) or HFD-0.1 % methionine and choline-deficient diet (MCD) to emulate simple hepatic steatosis or non-alcoholic steatohepatitis, respectively. In both models, aerobic exercise decreased the size of LDs bound to mitochondria and the number of LD-mitochondria contacts. Analysis showed that the effects of exercise on HOMA-IR and liver triglyceride levels were independent of changes in body weight, and a positive correlation was observed between the number of LD-mitochondria contacts and NAFLD severity and with the lipid droplet size bound to mitochondria. Cellular fractionation studies revealed that ATP-coupled respiration and fatty acid oxidation (FAO) were greater in hepatic peridroplet mitochondria (PDM) from HFD-fed exercised mice than from equivalent sedentary mice. Finally, exercise increased FAO and mitofusin-2 abundance exclusively in PDM through a mechanism involving the curvature of mitochondrial membranes and the abundance of saturated lipids. Accordingly, hepatic mitofusin-2 ablation prevented exercise-induced FAO in PDM. Conclusions: This study demonstrates that aerobic exercise has beneficial effects in murine NAFLD models by lessening the interactions between hepatic LDs and mitochondria, and by decreasing LD size, correlating with a reduced severity of NAFLD. Additionally, aerobic exercise increases FAO in PDM and this process is reliant on Mfn-2 enrichment, which modifies LD-mitochondria communication.2024-02-27T13:50:53ZComprehensive analysis of the effective and intra-particle diffusion of weakly retained compounds in silica hydrophilic interaction liquid chromatography columns
http://hdl.handle.net/2445/206823
Title: Comprehensive analysis of the effective and intra-particle diffusion of weakly retained compounds in silica hydrophilic interaction liquid chromatography columns
Author: Redón, Lídia; Subirats i Vila, Xavier; Chapel, Soraya; Januarius, Timothy; Broeckhoven, Ken; Rosés Pascual, Martí; Cabooter, Deirdre; Desmet, Gert
Abstract: A detailed analysis of intra-particle volumes and layer thicknesses and their effect on the diffusion of solutes in hydrophilic interaction liquid chromatography (HILIC) was made. Pycnometric measurements and the retention volume of deuterated mobile phase constituents (water and acetonitrile) were used to estimate the void volume inside the column, including not only the volume of the mobile phase but also part of the enriched water solvent acting as the stationary phase in HILIC. The mobile phase (hold-up) volume accessible to non-retained components was estimated using a homologous series approach. The joint analysis of the different approaches indicated the formation of enriched water layers on the hydrophobic silica mesopore walls with a thickness varying significantly with mobile phase composition. The maximal thickness of the enriched water layers, which corresponded to the minimum void volume accessible to unretained solutes, marked a transition in the retention behavior of the studied analytes. Discrepancies between deuterated solvent measurements and pycnometry were explained by the existence of an irreplaceable water layer adsorbed on the silica surface. Regarding the diffusion behavior in HILIC, peak parking experiments were used to interpret the influence of the acetonitrile content on the effective diffusion coefficient Deff. A systematic decrease in Deff and molecular diffusion Dm was observed with decreasing acetonitrile concentration, primarily attributed to variations in mobile phase viscosity. Notably, Deff/Dm remained nearly unaffected by variations in mobile phase composition. Finally, the effective medium theory was used to make a comprehensive analysis of Dpart/Dm to study the contribution to band broadening when the solute resides in the mesopores. The obtained data unveiled a curvature with a minimum corresponding to conditions of maximum water-layer thickness and retention. For the weakly retained compounds (k' < 0.5) the Dpart/Dm-values were found to be relatively high (order of 0.35-0.5), which directly reflects the high γsDs/Dm-values that were observed (order 0.35-7).2024-01-31T16:32:27ZCharacterization of solute-solvent interactions in liquid chromatography systems: A fast method based on Abraham's linear solvation energy relationships
http://hdl.handle.net/2445/202113
Title: Characterization of solute-solvent interactions in liquid chromatography systems: A fast method based on Abraham's linear solvation energy relationships
Author: Redón, Lídia; Beiranvand, Mahmoud Safar; Subirats i Vila, Xavier; Rosés Pascual, Martí
Abstract: The Abraham's solvation parameter model, based on linear solvation energy relationships (LSER), allows the accurate characterization of the selectivity of chromatographic systems according to solute-solvent interactions (polarizability, dipolarity, hydrogen bonding, and cavity formation). However, this method, based on multilinear regression analysis, requires the measurement of the retention factors of a considerably high number of compounds, turning it into a time-consuming low throughput method. Simpler methods such as Tanaka's scheme are preferred. In the present work, the Abraham's model is revisited to develop a fast and reliable method, similar to the one proposed by Tanaka, for the characterization of columns employed in reversed-phase liquid chromatography and particularly in hydrophilic interaction liquid chromatography. For this purpose, pairs of compounds are carefully selected in order to have in common all molecular descriptors except for a specific one (for instance, similar molecular volume, dipolarity, polarizability, and hydrogen bonding basicity features, but different hydrogen bonding acidity). Thus, the selectivity factor of a single pair of test compounds can provide information regarding the extent of the dissimilar solute-solvent interactions and their influence on chromatographic retention. The proposed characterization method includes the determination of the column hold-up volume and Abraham's cavity term by means of the injection of four alkyl ketone homologues. Therefore, five chromatographic runs in a reversed-phase column (four pairs of test solutes and a mixture of four homologues) are enough to characterize the selectivity of a chromatographic system. Tanaka's method is also analyzed from the LSER point of view.2023-09-20T15:04:14ZA near-infrared light-activatable Ru(II)-coumarin photosensitizer active under hypoxic conditions
http://hdl.handle.net/2445/201946
Title: A near-infrared light-activatable Ru(II)-coumarin photosensitizer active under hypoxic conditions
Author: Ortega-Forte, Enrique; Rovira, Anna; López-Corrales, Marta; Hernández-García, Alba; Ballester, Francisco José; Izquierdo-García, Eduardo Jorda-Redondo, M.; Bosch Marimon, Manel; Nonell, Santi; Santana, María Dolores; Ruiz, José; Marchán Sancho, Vicente; Gasser, Gilles
Abstract: Photodynamic therapy (PDT) represents a promising approach for cancer treatment. However, the oxygen dependency of PDT to generate reactive oxygen species (ROS) hampers its therapeutic efficacy, especially against hypoxic solid tumors. In addition, some photosensitizers (PSs) have dark toxicity and are only activatable with short wavelengths such as blue or UV-light, which suffer from poor tissue penetration. Herein, we developed a novel hypoxia-active PS with operability in the near-infrared (NIR) region based on the conjugation of a cyclometalated Ru(II) polypyridyl complex of the type [Ru(C^N)(N^N)2] to a NIR-emitting COUPY dye. The novel Ru(II)-coumarin conjugate exhibits water-solubility, dark stability in biological media and high photostability along with advantageous luminescent properties that facilitate both bioimaging and phototherapy. Spectroscopic and photobiological studies revealed that this conjugate efficiently generates singlet oxygen and superoxide radical anions, thereby achieving high photoactivity toward cancer cells upon highly-penetrating 740 nm light irradiation even under hypoxic environments (2% O2). The induction of ROS-mediated cancer cell death upon low-energy wavelength irradiation along with the low dark toxicity exerted by this Ru(II)-coumarin conjugate could circumvent tissue penetration issues while alleviating the hypoxia limitation of PDT. As such, this strategy could pave the way to the development of novel NIR- and hypoxia-active Ru(II)-based theragnostic PSs fuelled by the conjugation of tunable, low molecular-weight COUPY fluorophores.2023-09-15T09:11:54ZThe Phosphorylation of Kv1.3: A Modulatory Mechanism for a Multifunctional Ion Channel
http://hdl.handle.net/2445/201184
Title: The Phosphorylation of Kv1.3: A Modulatory Mechanism for a Multifunctional Ion Channel
Author: Navarro Pérez, María; Estadella, Irene; Benavente Garcia, Anna; Orellana Fernández, Ruth; Petit, Anna; Ferreres, Joan C.; Felipe Campo, Antonio
Abstract: The voltage-gated potassium channel Kv1.3 plays a pivotal role in a myriad of biological processes, including cell proliferation, differentiation, and apoptosis. Kv1.3 undergoes fine-tuned regulation, and its altered expression or function correlates with tumorigenesis and cancer progression. Moreover, posttranslational modifications (PTMs), such as phosphorylation, have evolved as rapid switch-like moieties that tightly modulate channel activity. In addition, kinases are promising targets in anticancer therapies. The diverse serine/threonine and tyrosine kinases function on Kv1.3 and the effects of its phosphorylation vary depending on multiple factors. For instance, Kv1.3 regulatory subunits (KCNE4 and Kvβ) can be phosphorylated, increasing the complexity of channel modulation. Scaffold proteins allow the Kv1.3 channelosome and kinase to form protein complexes, thereby favoring the attachment of phosphate groups. This review compiles the network triggers and signaling pathways that culminate in Kv1.3 phosphorylation. Alterations to Kv1.3 expression and its phosphorylation are detailed, emphasizing the importance of this channel as an anticancer target. Overall, further research on Kv1.3 kinase-dependent effects should be addressed to develop effective antineoplastic drugs while minimizing side effects. This promising field encourages basic cancer research while inspiring new therapy development.2023-07-26T09:32:12ZThe Prohibitin-Binding Compound Fluorizoline Activates the Integrated Stress Response through the eIF2α Kinase HRI
http://hdl.handle.net/2445/200924
Title: The Prohibitin-Binding Compound Fluorizoline Activates the Integrated Stress Response through the eIF2α Kinase HRI
Author: Sánchez Vera, Ismael; Núñez Vázquez, Sonia; Saura Esteller, José; Cosialls Castel, Ana Mª; Heib, Judith; Nadal Rodríguez, Pau; Ghashghaei, Ouldouz; Lavilla Grífols, Rodolfo; Pons i Irazazábal, Gabriel; Gil i Santano, Joan; Iglesias Serret, Daniel
Abstract: Fluorizoline is a synthetic molecule that induces apoptosis, by selectively targeting prohibitins (PHBs), through induction of the BH3-only protein NOXA. This induction is transcriptionally regulated by the integrated stress response (ISR)-related transcription factors ATF3 and ATF4. Here, we evaluate the role of the four eIF2a kinases, to decipher which is responsible for the mechanism of ISR activation triggered by fluorizoline in HeLa and HAP1 cells. First, we demonstrated the involvement of the eIF2a kinases using ISR inhibitor (ISRIB) and by simultaneous downregulation of all four eIF2a kinases, as both approaches were able to increase cell resistance to fluorizoline-induced apoptosis. Furthermore, we confirmed that fluorizoline treatment results in endoplasmic reticulum (ER) stress, as evidenced by PERK activation. Despite PERK activation, this kinase was not directly involved in the ISR activation by fluorizoline. In this regard, we found that the eIF2a kinases are capable of compensating for each other's loss of function. Importantly, we demonstrated that the mitochondrial-stress-related eIF2a kinase HRI mediates ISR activation after fluorizoline treatment.2023-07-19T11:40:45Z3D bioprinted functional skeletal muscle models have potential applications for studies of muscle wasting in cancer cachexia
http://hdl.handle.net/2445/200900
Title: 3D bioprinted functional skeletal muscle models have potential applications for studies of muscle wasting in cancer cachexia
Author: García Lizarribar, Andrea; Villasante, Aranzazu; Lopez Martin, Jose Antonio; Flandez, Marta; Soler Vázquez, M. Carmen; Serra, Dolors; Herrero, Laura; Sagrera, Ana; Efeyan, Alejo; Samitier i Martí, Josep
Abstract: Acquired muscle diseases such as cancer cachexia are responsible for the poor prognosis of many patients suffering from cancer. In vitro models are needed to study the underlying mechanisms of those pathologies. Extrusion bioprinting is an emerging tool to emulate the aligned architecture of fibers while implementing ad- ditive manufacturing techniques in tissue engineering. However, designing bioinks that reconcile the rheological needs of bioprinting and the biological requirements of muscle tissue is a challenging matter. Here we formulate a biomaterial with dual crosslinking to modulate the physical properties of bioprinted models. We design 3D bioprinted muscle models that resemble the mechanical properties of native tissue and show improved prolif- eration and high maturation of differentiated myotubes suggesting that the GelMA-AlgMA-Fibrin biomaterial possesses myogenic properties. The electrical stimulation of the 3D model confirmed the contractile capability of the tissue and enhanced the formation of sarcomeres. Regarding the functionality of the models, they served as platforms to recapitulate skeletal muscle diseases such as muscle wasting produced by cancer cachexia. The genetic expression of 3D models demonstrated a better resemblance to the muscular biopsies of cachectic mouse models. Altogether, this biomaterial is aimed to fabricate manipulable skeletal muscle in vitro models in a non- costly, fast and feasible manner2023-07-19T10:04:09ZMechanism of reaction of RNA-dependent RNA polymerase from SARS-CoV-2
http://hdl.handle.net/2445/200328
Title: Mechanism of reaction of RNA-dependent RNA polymerase from SARS-CoV-2
Author: Aranda, Juan; Wieczor, Milosz; Terrazas Martínez, Montserrat; Brun Heath, Isabelle; Orozco López, Modesto
Abstract: We combine molecular dynamics, statistical mechanics, and hybrid quantum mechanics/molecular mechanics simulations to describe mechanistically the severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) RNA-dependent RNA polymerase (RdRp). Our study analyzes the binding mode of both natural triphosphate substrates as well as remdesivir triphosphate (the active form of drug), which is bound preferentially over ATP by RdRp while being poorly recog- nized by human RNA polymerase II (RNA Pol II). A comparison of incorporation rates between natural and antiviral nucleotides shows that remdesivir is incorporated more slowly into the nascent RNA compared with ATP, leading to an RNA duplex that is structurally very similar to an unmodified one, arguing against the hypothesis that remdesivir is a competitive inhibitor of ATP. We characterize the entire mechanism of reaction, finding that viral RdRp is highly processive and displays a higher catalytic rate of incorporation than human RNA Pol II. Overall, our study provides the first detailed explanation of the replication mechanism of RdRp.2023-07-05T11:00:48ZEffect of the solvent on the chromatographic selectivity in reversed-phase and HILIC
http://hdl.handle.net/2445/199472
Title: Effect of the solvent on the chromatographic selectivity in reversed-phase and HILIC
Author: Subirats i Vila, Xavier; Casanovas, Laura; Redón, Lídia; Rosés Pascual, Martí
Abstract: In this work, the characterization of several reversed-phase and HILIC chromatographic systems is presented by means of the Abraham's solvation parameter model, focusing on the impact of solute polarizability, dipolarity, hydrogen bonding, and molecular volume on chromatographic retention. Although retention times in octadecylsilane columns are clearly dependent on the nature and content of the organic modifier in the mobile phase, similar chromatographic selectivities are reported for eluents containing acetonitrile or methanol in the range between 40 and 80%. The most relevant analyte properties affecting retention are the hydrogen bond acceptor capacity and the molecular volume, the former favoring partition into the mobile phase and the latter into the stationary phase. The behavior of HILIC systems greatly depends on the nature of the support (silica or polymeric), the bonded phase (zwitterionic, aminopropyl, dihydroxypropyl) and the organic solvent used in the eluent (acetonitrile or methanol), but they have in common that larger solute volumes allow more favorable partition into the organic solvent-rich mobile phase. The evaluation of the chromatographic retention of ionized analytes in HILIC should be performed with care, since they may interact with ionized buffering species, leading to unexpected lower retentions.2023-06-19T17:17:51Z