Investigación

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Investigación contiene los documentos generados por los docentes e investigadores de la Universidad en su labor de investigación. Este depósito tiene como objetivos el almacenamiento, la gestión, la preservación y la difusión de estos documentos, y pretende contribuir al aumento de la visibilidad del trabajo desarrollado por los miembros de la comunidad universitaria.

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Open Access
4-octyl itaconate reduces NLRP3 inflammasome constitutive activation with cryopyrin-associated periodic syndrome p.R262W, p.D305N and p.T350M variants
(Springer, Birkhäuser Verlag, 2025-05-23) Molina-López, Cristina; Hurtado-Navarro, Laura; O'Neill, Luke A.J.; Pelegrin, Pablo; Bioquímica y Biología Molecular B e Inmunología
Cryopyrin-associated periodic syndrome (CAPS) is a condition characterized by dominant genetic variants in the NLRP3 gene, leading to the formation of constitutively active inflammasomes. These inflammasomes play a crucial role in the inflammatory episodes experienced by CAPS patients, primarily driven by the production of interleukin (IL)-1. Although treatment with IL-1 blockers is effective for CAPS, some patients develop refractory responses and adverse reactions to these therapies. Consequently, there is a need for novel treatments for CAPS patients. Promising candidates are the derivatives of itaconate, which have been shown to impair NLRP3 inflammasome activation and IL-1 release in blood mononuclear cells from CAPS patients. In this study, we provide insight into the inhibitory mechanisms of the itaconate derivative 4-octyl itaconate (4-OI) on NLRP3 with different (p.R262W, p.D305N and p.T350M) gain-of-function mutations associated with CAPS. Notably, 4-OI effectively blocks the basal auto-activation of the inflammasome formed by NLRP3 p.R262W, p.D305N and p.T350M variants, resulting in reduced caspase-1 activation, gasdermin D processing, and IL-18 release. Furthermore, after lipopolysaccharide priming of macrophages, 4-OI also decreases IL-1 gene expression and release. Overall, 4-OI impairs CAPS p.D305N-associated inflammasome function at multiple levels, and therapeutic agents based on itaconate could be a promising therapeutic approach to managing inflammatory episodes in CAPS patients carrying p.R262W, p.D305N or p.T350M variants.
Open Access
A compressive review about Taxol® : history and future challenges
(MDPI, 2020-12-17) Gallego Jara, Julia; Lozano Terol, Gema; Sola Martinez, Rosa Alba; Cánovas Diaz, Manuel; De Diego Puente, María Teresa; Bioquímica y Biología Molecular B e Inmunología
Taxol®, which is also known as paclitaxel, is a chemotherapeutic agent widely used to treat different cancers. Since the discovery of its antitumoral activity, Taxol® has been used to treat over one million patients, making it one of the most widely employed antitumoral drugs. Taxol® was the first microtubule targeting agent described in the literature, with its main mechanism of action consisting of the disruption of microtubule dynamics, thus inducing mitotic arrest and cell death. However, secondary mechanisms for achieving apoptosis have also been demonstrated. Despite its wide use, Taxol® has certain disadvantages. The main challenges facing Taxol® are the need to find an environmentally sustainable production method based on the use of microorganisms, increase its bioavailability without exerting adverse effects on the health of patients and minimize the resistance presented by a high percentage of cells treated with paclitaxel. This review details, in a succinct manner, the main aspects of this important drug, from its discovery to the present day. We highlight the main challenges that must be faced in the coming years, in order to increase the effectiveness of Taxol® as an anticancer agent.
Embargo
A genetically encoded IL-1β BRET sensor to monitor inflammasome activity
(Asociación Americana de Inmunología, 2012) Compan, Vincent; Baroja-Mazo, Alberto; Bragg, Laricia; Verkhratsky, Alexei; Perroy, Julie; Pelegrin, Pablo; Bioquímica y Biología Molecular B e Inmunología
Inflammation is fundamental for protecting the organism against infection and injury. However, a failure to control immune response results in chronic inflammation and several associated disorders such as pain and loss of function. Initiation of inflammation is orchestrated by cytokines, among which interleukin (IL)-1β is particularly important. IL- 1β is synthesized as an inactive protein that has to be processed by the inflammasome to generate the mature bioactive form. Conventional techniques cannot monitor IL-1β activation with high spatial and temporal resolution. Here, we present a ratiometric biosensor that allows monitoring IL-1β processing in real-time, with a temporal resolution of seconds and with a single cell spatial resolution. Using this sensor, we describe for the first time the kinetic of the inflammasome activity in living macrophages. With this new probe we also demonstrated that the pro-IL-1β processing occurs all over the cytoplasm.
Open Access
A green chemo-enzymatic approach for CO2 capture and transformation into bis(cyclic carbonate) esters in solvent-free media
(American Chemical Society, 2024-10-02) Villa Aroca, Rocío; Ruiz, Francisco J.; Velasco, Francisco; Nieto, Susana; Porcar, Raul; Garcia Verdugo, Eduardo; Lozano, Pedro; Bioquímica y Biología Molecular B e Inmunología
A sustainable approach for CO2 capture and chemo-enzymatic transformation into bis(cyclic carbonate) esters from CO2, glycidol and organic anhydrides under solvent-free conditions has been demonstrated. The chemo-enzymatic process is based in two consecutive catalytic steps, which can be executed through separated operations, or within a one-pot combo system, taking advantage of the synergic effects that emerge from integrating ionic liquid (ILs) technologies and biocatalysts. In a first step, lipase-catalyzed transesterification and esterification reactions of different diacyl donors (e.g. glutaric anhydride, succinic anhydride, dimethyl succinate, etc.) with glycidol in solvent-free under mild reaction conditions (70 °C, 6 h), producing the corresponding diglycidyl esters derivatives up to 41% yield. By a second step, the synthesis of bis(cyclic carbonate) esters was carried out as results of the cycloaddition reaction of CO2 (from an exhausted gas source, 15% CO2 purity) on these diglycidyl esters, catalyzed by the covalently attached 1-decyl-2-methylimidazolium IL (Supported Ionic Liquid-Like Phase, SILLP), in solvent-free, leading up to 65% yield after 8 h at 50 °C and 1MPa CO2 pressure. Both key elements of the reaction system (biocatalyst and SILLP) were successfully recovered and reused for at least 5 operational cycles. Finally, different metrics have been applied to assess the greenness of the solvent-free chemo-enzymatic synthesis of bis(cyclic carbonate) esters here reported.
Embargo
A novel CD14high CD16high subset of peritoneal macrophages from cirrhotic patients is associated to an increased response to LPS
(Elsevier, 2016-03-01) Martínez-Esparza, M.; Ruiz-Alcaraz, Antonio José; Tapia-Abellán, Ana; Fernández-Fernández, María Dolores; Tristán-Manzano, María; Hernández-Caselles, Trinidad; Sánchez-Velasco, Eduardo; Miras-López, Manuel; García-Penarrubia, Pilar; Bioquímica y Biología Molecular B e Inmunología
The aim of this study was to characterize monocyte-derived macrophages (M-DM) from blood and ascites of cirrhotic patients comparatively with those obtained from blood of healthy controls. The phenotypic profile based on CD14/CD16 expression was analyzed by flow cytometry. Cells were isolated and stimulated in vitro with LPS and heat killed Candida albicans. Phosphorylation of ERK, c-Jun, p38 MAPK, and PKB/Akt was analyzed by Western blotting. A novel CD14(high)CD16(high) M-DM subpopulation is present in ascites (∼33%). The CD14(++)CD16(+) intermediate subset is increased in the blood of cirrhotic patients (∼from 4% to 11%) and is predominant in ascites (49%), while the classical CD14(++)CD16(-) subpopulation is notably reduced in ascites (18%). Basal hyperactivation of ERK and JNK/c-Jun pathways observed in ascites M-DM correlates with CD14/CD16 high expressing subsets, while PI3K/PKB does it with the CD16 low expressing cells. In vitro LPS treatment highly increases ERK1/2, PKB/Akt and c-Jun phosphorylation, while that of p38 MAPK is decreased in M-DM from ascites compared to control blood M-DM. Stimulation of healthy blood M-DM with LPS and C. albicans induced higher phosphorylation levels of p38 than those from ascites. Regarding cytokines secretion, in vitro activated M-DM from ascites of cirrhotic patients produced significantly higher amounts of IL-6, IL-10 and TNF-α, and lower levels of IL-1β and IL-12 than control blood M-DM. In conclusion, a new subpopulation of CD14(high)CD16(high) peritoneal M-DM has been identified in ascites of cirrhotic patients, which is very sensitive to LPS stimulation.
Open Access
A Side-by-Side comparison of wildtype and variant melanocortin 1 receptor signaling with emphasis on protection against oxidative damage to DNA.
(MDPI, 2023-09-21) Cerdido, Sonia; Sánchez-Beltrán, José; Lambertos, Ana; Abrisqueta, Marta; Padilla, Lidia; Herraiz Serrano, Cecilia María; Jiménez-Cervantes, Celia; García-Borrón, José Carlos; Olivares, Conchi; Bioquímica y Biología Molecular B e Inmunología
Common variants of the MC1R gene coding the α-melanocyte stimulating hormone receptor are associated with light skin, poor tanning, blond or red hair, and increased melanoma risk, due to pigment-dependent and -independent effects. This complex phenotype is usually attributed to impaired activation of cAMP signaling. However, several MC1R variants show significant residual coupling to cAMP and efficiently activate mitogenic extracellular signal-regulated kinase 1 and 2 (ERK1/2) signaling. Yet, residual signaling and the key actions of wildtype and variant MC1R have never been assessed under strictly comparable conditions in melanocytic cells of identical genetic background. We devised a strategy based on CRISPR-Cas9 knockout of endogenous MC1R in a human melanoma cell line wildtype for BRAF, NRAS and NF1, followed by reconstitution with epitope-labeled MC1R constructs, and functional analysis of clones expressing comparable levels of wildtype, R151C or D294H MC1R. The proliferation rate, shape, adhesion, motility and sensitivity to oxidative DNA damage were compared. The R151C and D294H RHC variants displayed impaired cAMP signaling, intracellular stability similar to the wildtype, triggered ERK1/2 activation as effectively as the wildtype, and afforded partial protection against oxidative DNA damage, although less efficiently than the wildtype. Therefore, common melanoma-associated MC1R variants display biased signaling and significant genoprotective activity.
Open Access
Acidophilic granulocytes of the marine fish gilthead seabream (Sparus aurata L.) produce interleukin-1b following infection with Vibrio anguillarum
(Springer, 2004) Chaves-Pozo, Elena; Pelegrin, Pablo; García-Castillo, Jesús; García-Ayala, Alfonsa; Mulero, Victoriano; Meseguer, José; Bioquímica y Biología Molecular B e Inmunología
The fish immune response to Gram-negative bacteria is poorly understood. In this study, we use a monoclonal antibody (mAb) specific to acidophilic granulocytes from the marine fish gilthead seabream (Sparus aurata L.), together with an antiserum specific to interleukin-1b (IL-1b) from this species, in order to investigate whether these cells are involved in the immune response against the pathogenic bacterium Vibrio anguillarum and, in particular, in the production of the pro-inflammatory cytokine IL-1b. We found that gilthead seabream head- kidney, peritoneal exudate and peripheral blood leukocytes accumulated proIL-1b intracellularly when challenged in vitro with V. anguillarum, whereas only peritoneal exudate and blood leukocytes were able to accumulate proIL-1b following infection. Importantly, the blood leukocytes from infected animals that accumulated proIL-1b were shown to be the acidophilic granulocytes. A rapid mobilization of such cells from the head-kidney to the site of inflammation following infection with V. anguillarum was also observed.
Open Access
Age-related oxidative stress compromises endosomal proteostasis
Cannizzo, Elvira S.; Clement, Cristina C.; Morozova, Kateryna; Valdor, Rut; Kaushik, Susmita; Almeida, Larissa N.; Follo, Carlo; Sahu, Ranjit; Cuervo, Ana María; Macian, Fernando; Santambrogio, Laura; Bioquímica y Biología Molecular B e Inmunología
A hallmark of aging is an imbalance between production and clearance of reactive oxygen species and increased levels of oxidatively damaged biomolecules. Herein we demonstrate that splenic and nodal antigen presenting cells purified from old mice accumulate oxidatively modified proteins with side chain carbonylation, advanced glycation end products and lipid peroxidation. We show further that the endosomal accumulation of oxidatively modified proteins interferes with the efficient processing of exogenous antigens and degradation of macroautophagy-delivered proteins. In support of a causative role for oxidized products in the inefficient immune response, a decrease in oxidative stress improved the adaptive immune response to immunizing antigens. These findings underscore a previously unrecognized negative effect of age-dependent changes in cellular proteostasis on the immune response.
Embargo
Air pollution from traffic during pregnancy impairs newborn's cord blood immune cells: The NELA cohort
(ELSEVIER, 2021) García-Serna, Azahara M; Hernández-Caselles, Trinidad; Jiménez-Guerrero, Pedro; Martín-Orozco, Elena; Pérez-Fernández, Virginia; Cantero-Cano, Esther; Muñoz-García, María; Ballesteros-Meseguer, Carmen; Pérez de Los Cobos, Irene; García-Marcos, Luis; Morales, Eva; NELA Study group; Bioquímica y Biología Molecular B e Inmunología
Background: Hazards of traffic-related air pollution (TRAP) on the developing immune system are poorly understood. We sought to investigate the effects of prenatal exposure to TRAP on cord blood immune cell distributions; and to identify gestational windows of susceptibility. Methods: In-depth immunophenotyping of cord blood leukocyte and lymphocyte subsets was performed by flow cytometry in 190 newborns embedded in the Nutrition in Early Life and Asthma (NELA) birth cohort (2015-2018). Long-term (whole pregnancy and trimesters) and short-term (15-days before delivery) residential exposures to traffic-related nitrogen dioxide (NO2), particulate matter (PM2.5 and PM10), and ozone (O3) were estimated using dispersion/chemical transport modelling. Associations between TRAP concentrations and cord blood immune cell counts were assessed using multivariate Poisson regression models. Results: Mean number of natural killer (NK) cells decreased 15% in relation to higher NO2 concentrations (≥36.4 μg/m3) during whole pregnancy (incidence relative risk (IRR), 0.85; 95% CI, 0.72, 0.99), with stronger associations in the first trimester. Higher PM2.5 concentrations (≥13.3 μg/m3) during whole pregnancy associated with a reduced mean number of cytotoxic T cells (IRR, 0.88; 95% CI, 0.78, 0.99). Newborns exposed to higher PM10 (≥23.6 μg/m3) and PM2.5 concentrations during the first and third trimester showed greater mean number of helper T type 1 (Th1) cells (P < 0.05). Decreased number of regulatory T (Treg) cells was associated with greater short-term NO2 (IRR, 0.90; 95% CI, 0.80, 1.01) and PM10 (IRR, 0.88; 95% CI, 0.77, 0.99) concentrations. Conclusions: Prenatal exposure to TRAP, particularly in early and late gestation, impairs fetal immune system development through disturbances in cord blood leukocyte and lymphocyte distributions.
Open Access
Air pollution from traffic during pregnancy impairs newborn's cord blood immune cells: The NELA cohort
(2020-11-17) García-Serna, Azahara M; Hernández-Caselles, Trinidad; Jiménez-Guerrero, Pedro; Martín-Orozco, Elena; Pérez-Fernández, Virginia; Cantero-Cano, Esther; Muñoz-García, María; Ballesteros-Meseguer, Carmen; Pérez de los Cobos, Irene; García-Marcos, Luis; Morales, Eva; Bioquímica y Biología Molecular B e Inmunología
Background: Hazards of traffic-related air pollution (TRAP) on the developing immune system are poorly understood. We sought to investigate the effects of prenatal exposure to TRAP on cord blood immune cell distributions; and to identify gestational windows of susceptibility. Methods: In-depth immunophenotyping of cord blood leukocyte and lymphocyte subsets was performed by flow cytometry in 190 newborns embedded in the Nutrition in Early Life and Asthma (NELA) birth cohort (2015-2018). Long-term (whole pregnancy and trimesters) and short-term (15-days before delivery) residential exposures to traffic-related nitrogen dioxide (NO2), particulate matter (PM2.5 and PM10), and ozone (O3) were estimated using dispersion/chemical transport modelling. Associations between TRAP concentrations and cord blood immune cell counts were assessed using multivariate Poisson regression models. Results: Mean number of natural killer (NK) cells decreased 15% in relation to higher NO2 concentrations (≥36.4 μg/m3) during whole pregnancy (incidence relative risk (IRR), 0.85; 95% CI, 0.72, 0.99), with stronger associations in the first trimester. Higher PM2.5 concentrations (≥13.3 μg/m3) during whole pregnancy associated with a reduced mean number of cytotoxic T cells (IRR, 0.88; 95% CI, 0.78, 0.99). Newborns exposed to higher PM10 (≥23.6 μg/m3) and PM2.5 concentrations during the first and third trimester showed greater mean number of helper T type 1 (Th1) cells (P < 0.05). Decreased number of regulatory T (Treg) cells was associated with greater short-term NO2 (IRR, 0.90; 95% CI, 0.80, 1.01) and PM10 (IRR, 0.88; 95% CI, 0.77, 0.99) concentrations. Conclusions: Prenatal exposure to TRAP, particularly in early and late gestation, impairs fetal immune system development through disturbances in cord blood leukocyte and lymphocyte distributions.
Open Access
Amino acid residues in the P2X7 receptor that mediate differential sensitivity to ATP and BzATP
(American Society for Pharmacology and Experimental Therapeutics, 2007) Young, Mark T.; Pelegrin, Pablo; Surprenant, Annmarie; Bioquímica y Biología Molecular B e Inmunología
Agonist properties of the P2X7 receptor (P2X7R) differ strikingly from other P2X receptors in two main ways: high concentrations of ATP (> 100 microM) are required to activate the receptor, and the ATP analog 2',3'-O-(4-benzoyl-benzoyl)ATP (BzATP) is both more potent than ATP and evokes a higher maximum current. However, there are striking species differences in these properties. We sought to exploit the large differences in ATP and BzATP responses between rat and mouse P2X7R to delineate regions or specific residues that may be responsible for the unique actions of these agonists at the P2X7R. We measured membrane currents in response to ATP and BzATP at wild-type rat and mouse P2X7R, at chimeric P2X7Rs, and at mouse P2X7Rs bearing point mutations. Wild-type rat P2X7R was 10 times more sensitive to ATP and 100 times more sensitive to BzATP than wild-type mouse P2X7R. We found that agonist EC50 values were determined solely by the ectodomain of the P2X7R. Two segments (residues 115-136 and 282-288), when transposed together, converted mouse sensitivities to those of rat. Point mutations through these regions revealed a single residue, asparagine284, in the rat P2X7R that fully accounted for the 10-fold difference in ATP sensitivity, whereas the 100-fold difference in BzATP sensitivity required the transfer of both Lys127 and Asn284 from rat to mouse. Thus, single amino acid differences between species can account for large changes in agonist effectiveness and differentiate between the two widely used agonists at P2X7 receptors.
Open Access
An acetylatable lysine controls CRP function in E. coli.
(John Wiley & Sons, 2017-10-31) Davis, Robert; Ecija Conesa, Ana; Gallego Jara, Julia; De Diego Puente, María Teresa; Filippova, Ekaterina V.; Schilling, Birgit; Anderson, Wayne F.; Gibson, Bradford W.; Cánovas Diaz, Manuel; Wolfe, Alan J.; Kuffel, Gina; Bioquímica y Biología Molecular B e Inmunología
Transcriptional regulation is the key to ensuring that proteins are expressed at the proper time and the proper amount. In Escherichia coli, the transcription factor cAMP receptor protein (CRP) is responsible for much of this regulation. Questions remain, however, regarding the regulation of CRP activity itself. Here, we demonstrate that a lysine (K100) on the surface of CRP has a dual function: to promote CRP activity at Class II promoters, and to ensure proper CRP steady state levels. Both functions require the lysine’s positive charge; intriguingly, the positive charge of K100 can be neutralized by acetylation using the central metabolite acetyl phosphate as the acetyl donor. We propose that CRP K100 acetylation could be a mechanism by which the cell downwardly tunes CRPdependent Class II promoter activity, whilst elevating CRP steady state levels, thus indirectly increasing Class I promoter activity. This mechanism would operate under conditions that favor acetate fermentation, such as during growth on glucose as the sole carbon source or when carbon flux exceeds the capacity of the central metabolic pathways.
Open Access
An ideal spacing is required for the control of Class II CRP-dependent promoters by the status of CRP K100
(2020-11-11) Ecija Conesa, Ana; Gallego Jara, Julia; Lozano-Terol, Gema; Browning, Douglas F.; Busby, Steve J.W.; Wolfe, Alan J.; Cánovas Díaz, Manuel; De Diego Puente, María Teresa; Bioquímica y Biología Molecular B e Inmunología
Transcription activation by the Escherichia coli CRP at Class II promoters is dependent on direct interactions between RNA polymerase and CRP, therefore the spatial proximity between both proteins plays a significant role in the ability of CRP to activate transcription. Using both in vivo and in vitro techniques, here we demonstrate that the CRP K100 positive charge, adjacent to AR2, is required for full promoter activity when CRP is optimally positioned. Accordingly, K100 mediated activation is very position-dependent and our data confirm that the largest impact of the K100 status on transcription activation occurs when the spacing between the CRP binding site and the A2 of the -10 element is 22 bp. From the results of this study and the progress in the understanding about open complex DNA scrunching, we propose that CRP-dependent promoters should now be numbered by the distance from the centre of the DNA site for CRP and the most highly conserved base at position 2 of the -10 hexamer in bacterial promoters.
Open Access
An ideal spacing is required for the control of Class II CRP-dependent promoters by the status of CRP K100.
(Oxford Academic, 2020) Écija Conesa, Ana; Gallego Jara, Julia; Lozano Terol, Gema; Browning, Douglas F.; Busby, Steve J. W.; Wolfe, Alan J.; Canovas Diaz, Manuel; De Diego Puente, María Teresa; Bioquímica y Biología Molecular B e Inmunología
Transcription activation by the Escherichia coli CRP at Class II promoters is dependent on direct interactions between RNA polymerase and CRP, therefore the spatial proximity between both proteins plays a significant role in the ability of CRP to activate transcription. Using both in vivo and in vitro techniques, here we demonstrate that the CRP K100 positive charge, adjacent to AR2, is required for full promoter activity when CRP is optimally positioned. Accordingly, K100 mediated activation is very position-dependent and our data confirm that the largest impact of the K100 status on transcription activation occurs when the spacing between the CRP binding site and the A2 of the −10 element is 22 bp. From the results of this study and the progress in the understanding about open complex DNA scrunching, we propose that CRP-dependent promoters should now be numbered by the distance from the center of the DNA site for CRP and the most highly conserved base at position 2 of the −10 hexamer in bacterial promoters
Open Access
Analysis of the anti-inflammatory potential of Brassica bioactive compounds in a human macrophage-like cell model derived from HL-60 cells
(Elsevier, 2022-05) Ruiz Alcaraz, Antonio José; Martínez Sánchez, María Antonia; García Peñarrubia, Pilar; Martínez Esparza, M.; Ramos Molina, Bruno; Moreno, Diego A.; Bioquímica y Biología Molecular B e Inmunología
Background: Chronic inflammatory diseases are major causes of global morbidity and mortality. Acute inflammation is meant to protect the body against foreign agents, but it also plays a major role in tissue repairment. Several mediators are involved in this process, including pro-inflammatory cytokines produced by macrophages. Occasionally, if the inflammatory response is not resolved, the acute inflammatory process can evolve into a chronic inflammation. Natural compounds from vegetables are considered as an important source of active agents with potential to treat or prevent inflammatory related pathologies and could be used as an alternative of the therapeutic agents currently in use, such as non-steroidal anti-inflammatory drugs (NSAIDs), which present several side effects. Methods: In this research work we evaluated in vitro the anti-inflammatory activity of a series of ten phytochemicals present in Brassica, measured as the potential of those compounds to reduce the production of key proinflammatory cytokines (TNF-α, IL-6 and IL-1β) by a human macrophage-like cell model of HL-60 cells Results: Most of the tested phytochemicals (including the most representative bioactive molecules of the major classes of compounds present in cruciferous foods such as glucosinolates, isothiocyanates, hydroxycinnamic acids, flavonols and anthocyanins) demonstrated significant anti-inflammatory activity at micromolar level in the absence of cytotoxic effects in this human macrophage-like cell model. Conclusion: These data confirm that phytochemicals commonly obtained from Brassica may be potential therapeutic leads to treat or prevent human chronic inflammation and related diseases.
Open Access
Analysis of validamycin as a potential antifungal compound against Candida albicans
(Institut d’Estudis Catalans, 2013-12-12) Guirao Abad, José P.; Sánchez Fresneda, Ruth; Valentín, Eulogio; Martínez Esparza, M.; Argüelles, Juan Carlos; Bioquímica y Biología Molecular B e Inmunología
Validamycin A has been successfully applied in the fight against phytopathogenic fungi. Here, the putative antifungal effect of this pseudooligosaccharide against the prevalent human pathogen Candida albicans was examined. Validamycin A acts as a potent competitive inhibitor of the cell-wall-linked acid trehalase (Atc1p). The estimated MIC50 for the C. albicans parental strain CEY.1 was 500 mg/l. The addition of doses below MIC50 to exponentially growing CEY.1 cells caused a slight reduction in cell growth. A concentration of 1 mg/ml was required to achieve a significant degree of cell killing. The compound was stable as evidenced by the increased reduction of cell growth with increasing incubation time. A homozygous atc1delta/atc1delta mutant lacking functional Atc1p activity showed greater resistance to the drug. The antifungal power of validamycin A was limited compared with the drastic lethal action caused by exposure to amphotericin B. The endogenous content of trehalose rose significantly upon validamycin and amphotericin B addition. Neither serum-induced hypha formation nor the level of myceliation recorded in macroscopic colonies were affected by exposure to validamycin A. Our results suggest that, although validamycin A cannot be considered a clinically useful antifungal against C. albicans, its mechanism of action and antifungal properties provide the basis for designing new, clinically interesting, antifungal-related compounds.
Open Access
Anti-leukemia activity of 4-amino-2-aryl-6,9-dichlorobenzo[g]pteridines
(Springer, 2019-02) Ruiz-Alcaraz, Antonio J.; Carmona-Martínez, Violeta; Guirado, Antonio; Gálvez, Jesús; Martínez-Esparza, M.; García-Peñarrubia, Pilar; Bioquímica y Biología Molecular B e Inmunología
Embargo
Antifungal effects and mechanism of action of viscotoxin A3
(Federation of European Biochemical Societies [Society Publisher], 2006-01-01) Guidici Besseghini, Ana Marcela; Poveda Larrosa, José Antonio; Molina Gallego, María Luisa; Canal, Laura de la; González Ros, José Manuel; Pfüller, Karola; Pfüller, Uwe; Villalaín Boullón, José; Bioquímica y Biología Molecular B e Inmunología
Viscotoxins are cationic proteins, isolated from different mistletoe species, that belong to the group of thionins, a group of basic cysteine-rich peptides of ≈ 5 kDa. They have been shown to be cytotoxic to different types of cell, including animal, bacterial and fungal. The aim of this study was to obtain information on the cell targets and the mechanism of action of viscotoxin isoform A3 (VtA3). We describe a detailed study of viscotoxin interaction with fungal-derived model membranes, its location inside spores of Fusarium solani, as well as their induced spore death. We show that VtA3 induces the appearance of ion-channel-like activity, the generation of H2O2, and an increase in cytoplasmic free Ca2+. Moreover, we show that Ca2+ is involved in VtA3-induced spore death and increased H2O2 concentration. The data presented here strongly support the notion that the antifungal activity of VtA3 is due to membrane binding and channel formation, leading to destabilization and disruption of the plasma membrane, thereby supporting a direct role for viscotoxins in the plant defence mechanism.
Open Access
Antizyme Inhibitor 2-Deficient Mice Exhibit Altered Brain Polyamine Levels and Reduced Locomotor Activity
(MDPI, 2023-12-21) Lambertos, Ana; Nuñez Sánchez, María Ángeles; López García, Carlos; López Contreras, Andrés Joaquín; Ramos-Molina, Bruno; Peñafiel, Rafael; Bioquímica y Biología Molecular B e Inmunología
Alterations in the neural polyamine system are known to be associated with different brain pathological conditions. In addition, the regulation of enzymes involved in polyamine metabolism such as ornithine decarboxylase (ODC), antizymes (AZs), and antizyme inhibitors (AZINs) is critical during brain development. However, while most studies focus on ODC and AZs, less is known about AZIN expression and function in the brain. Thus, our aim was to analyze the expression pattern of AZIN2 during postnatal development, its brain distribution, and its possible implication in phenotypical alterations. Methods: The expression pattern of Azin2 and other genes related to polyamine metabolism was analyzed by RT-qPCR. beta-D-galactosidase staining was used to determine the anatomical distribution of AZIN2 in a Azin2 knockout model containing the beta Geo marker. Brain polyamine content was determined by HPLC. The Rota-Rod and Pole functional tests were used to evaluate motor skills in Azin2-lacking mice. Results: Our results showed that expression of genes codifying for AZs and AZINs showed a similar increasing pattern over time that coincided with a decrease in ODC activity and putrescine levels. The analysis of AZIN2 distribution demonstrated that it is strongly expressed in the cerebellum and distributed along the neuron body and dendrites. The ablation of Azin2 showed a decrease in putrescine levels and is related to reduced motor skills. Conclusions: Our study revealed that AZIN2 expression in the brain is particularly limited to the cerebellum. In addition, the ablation of Azin2 leads to a reduction in putrescine that relates to alterations in motor function, suggesting the role of AZIN2 in the functioning of dopaminergic neurons.
Open Access
Apoptosis-associated speck-like protein containing CARD forms specks but does not activate caspase-1 in the absence of NLRP3 during macrophage swelling
(The American Association of Immunologists, Inc., 2015) Compan, Vincent; Martín-Sánchez, Fátima; Baroja-Mazo, Alberto; López-Castejón, Gloria; Gomez, Ana I.; Verkhratsky, Alexei; Brough, David; Pelegrin Vivancos, Pablo; Bioquímica y Biología Molecular B e Inmunología
Apoptosis-associated speck-like protein containing a CARD (ASC) is a key adaptor molecule required for inflammatory processes. ASC acts by bridging NLRP proteins, such as NLRP3, with pro-caspase-1 within the inflammasome complex that subsequently results in the activation of caspase-1 and the secretion of interleukin (IL)-1b and IL-18. In response to bacterial infection, ASC also forms specks by self-oligomerization to activate caspase-1 and induce pyroptosis. Hitherto the role of these specks in NLRP3 inflammasome activation in response to danger signals is largely unexplored. Here we report that under hypotonic conditions, ASC formed specks independently of NLRP3 that did not activate caspase-1. These specks were not associated with pyroptosis and were controlled by Transient Receptor Potential Vanilloid 2 channel mediated signaling. However, interaction with NLRP3 enhanced ASC speck formation leading to fully functional inflammasomes and caspase-1 activation. This study reveals that the ASC speck could present different oligomerization assemblies and represents an essential step in the activation of functional NLRP3 inflammasomes.