Delgado Saavedra, María Jesús

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First Name
María Jesús
Last Name
Delgado Saavedra
Universidad Complutense de Madrid
Faculty / Institute
Ciencias Biológicas
Genética, Fisiología y Microbiología
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Now showing 1 - 10 of 24
  • Publication
    Ghrelin modulates gene and protein expression of digestive enzymes in the intestine and hepatopancreas of goldfish (Carassius auratus) via the GHS-R1a: Possible roles of PLC/PKC and AC/PKA intracellular signaling pathways
    (Elsevier, 2017-02-15) Blanco Imperiali, Ayelén M.; Bertucci, Juan I.; Sánchez Bretaño, Aída; Delgado Saavedra, María Jesús; Valenciano González, Ana Isabel; Unniappan, Suraj
    Ghrelin, a multifunctional gut-brain hormone, is involved in the regulation of gastric functions in mammals. This study aimed to determine whether ghrelin modulates digestive enzymes in goldfish (Carassius auratus). Immunofluorescence microscopy found colocalization of ghrelin, GHS-R1a and the digestive enzymes sucrase-isomaltase, aminopeptidase A, trypsin and lipoprotein lipase in intestinal and hepatopancreatic cells. In vitro ghrelin treatment in intestinal and hepatopancreas explant culture led to a concentration- and time-dependent modulation (mainly stimulatory) of most of the digestive enzymes tested. The ghrelin-induced upregulations of digestive enzyme expression were all abolished by preincubation with the GHS-R1a ghrelin receptor antagonist [D-Lys3]-GHRP-6, and most of them by the phospholipase C inhibitor U73122 or the protein kinase A inhibitor H89. This indicates that ghrelin effects on digestive enzymes are mediated by GHS-R1a, partly by triggering the PLC/PKC and AC/PKA intracellular signaling pathways. These data suggest a role for ghrelin on digestive processes in fish.
  • Publication
    Diurnal Profiles of N-Acylethanolamines in Goldfish Brain and Gastrointestinal Tract: Possible Role of Feeding
    (Frontiers Media, 2019-05-07) Gómez-Boronat, Miguel; Isorna Alonso, Esther; Armirotti, Andrea; Delgado Saavedra, María Jesús; Piomelli, Danielle; Pedro Ormeño, Nuria de
    N-acylethanolamines (NAEs) are a family of endogenous lipid signaling molecules that are involved in regulation of energy homeostasis in vertebrates with a putative role on circadian system. The aim of this work was to study the existence of daily fluctuations in components of NAEs system and their possible dependence on food intake. Specifically, we analyzed the content of oleoylethanolamide (OEA), palmitoylethanolamide (PEA), stearoylethanolamide (SEA), their precursors (NAPEs), as well as the expression of nape-pld (NAEs synthesis enzyme), faah (NAEs degradation enzyme), and pparα (NAEs receptor) in gastrointestinal and brain tissues of goldfish (Carassius auratus) throughout a 24-h cycle. Daily profiles of bmal1a and rev-erbα expression in gastrointestinal tissues were also quantified because these clock genes are also involved in lipid metabolism, are PPAR-targets in mammals, and could be a link between NAEs and circadian system in fish. Gastrointestinal levels of NAEs exhibited daily fluctuations, with a pronounced and rapid postprandial increase, the increment being likely caused by food intake as it is not present in fasted animals. Such periprandial differences were not found in brain, supporting that NAEs mobilization occurs in a tissue-specific manner and suggesting that these three NAEs could be acting as peripheral satiety signals. The abundance of pparα mRNA displayed a daily rhythm in the intestine and the liver, suggesting a possible rhythmicity in the NAEs functionality. The increment of pparα expression during the rest phase can be related with its role stimulating lipid catabolism to obtain energy during the fasting state of the animals. In addition, the clock genes bmal1a and rev-erbα also showed daily rhythms, with a bmal1a increment after feeding, supporting its role as a lipogenic factor. In summary, our data show the existence of all components of NAEs system in fish (OEA, PEA, SEA, precursors, synthesis and degradation enzymes, and the receptor PPARα), supporting the involvement of NAEs as peripheral satiety signals.
  • Publication
    Tissue-specific expression of ghrelinergic and NUCB2/nesfatin-1 systems in goldfish (Carassius auratus) is modulated by macronutrient composition of diets
    (Elsevier, 2016-05) Blanco Imperiali, Ayelén M.; Bertucci, Juan I.; Delgado Saavedra, María Jesús; Valenciano González, Ana Isabel; Unniappan, Suraj
    The macronutrient composition of diets is a very important factor in the regulation of body weight and metabolism. Several lines of research in mammals have shown that macronutrients differentially regulate metabolic hormones, including ghrelin and nesfatin-1 that have opposing effects on energy balance. This study aimed to determine whether macronutrients modulate the expression of ghrelin and the nucleobindin-2 (NUCB2) encoded nesfatin-1 in goldfish (Carassius auratus). Fish were fed once daily on control, high-carbohydrate, high-protein, high-fat and very high-fat diets for 7 (short-term) or 28 (long-term) days. The expression of preproghrelin, ghrelin O-acyl transferase (goat), growth hormone secretagogue receptor 1 (ghs-r1) and nucb2/nesfatin-1 mRNAs was quantified in the hypothalamus, pituitary, gut and liver. Short-term feeding with fat-enriched diets significantly increased nucb2 mRNA levels in hypothalamus and liver, preproghrelin, goat and ghs-r1 expression in pituitary, and ghs-r1 expression in gut. Fish fed on a high-protein diet exhibited a significant reduction in preproghrelin and ghs-r1 mRNAs in the liver. After long-term feeding, fish fed on high-carbohydrate and very high-fat diets had significantly increased preproghrelin, goat and ghs-r1 expression in pituitary. Feeding on a high-carbohydrate diet also upregulated goat and ghs-r1 transcripts in gut, while feeding on a high-fat diet elicited the same effect only for ghs-r1 in liver. Nucb2 expression increased in pituitary, while it decreased in gut after long-term feeding of a high-protein diet. Collectively, these results show for the first time in fish that macronutrients differentially regulate the expression of ghrelinergic and NUCB2/nesfatin-1 systems in central and peripheral tissues of goldfish.
  • Publication
    REV-ERBα Agonist SR9009 Promotes a Negative Energy Balance in Goldfish
    (MDPI, 2022-03-08) Saiz, Nuria; Herrera Castillo, Lisbeth; Isorna Alonso, Esther; Delgado Saavedra, María Jesús; Conde Sieira, Marta; Soengas, José L.; Pedro Ormeño, Nuria de
    REV-ERBα (nr1d1, nuclear receptor subfamily 1 group D member 1) is a transcriptional repressor that in mammals regulates nutrient metabolism, and has effects on energy homeostasis, although its role in teleosts is poorly understood. To determine REV-ERBα’s involvement in fish energy balance and metabolism, we studied the effects of acute and 7-day administration of its agonist SR9009 on food intake, weight and length gain, locomotor activity, feeding regulators, plasma and hepatic metabolites, and liver enzymatic activity. SR9009 inhibited feeding, lowering body weight and length gain. In addition, the abundance of ghrelin mRNA decreased in the intestine, and abundance of leptin-aI mRNA increased in the liver. Hypocretin, neuropeptide y (npy), and proopiomelanocortin (pomc) mRNA abundance was not modified after acute or subchronic SR9009 administration, while hypothalamic cocaine- and amphetamine-regulated transcript (cartpt-I) was induced in the subchronic treatment, being a possible mediator of the anorectic effects. Moreover, SR9009 decreased plasma glucose, coinciding with increased glycolysis and a decreased gluconeogenesis in the liver. Decreased triglyceride levels and activity of lipogenic enzymes suggest a lipogenesis reduction by SR9009. Energy expenditure by locomotor activity was not significantly affected by SR9009. Overall, this study shows for the first time in fish the effects of REV-ERBα activation via SR9009, promoting a negative energy balance by reducing energetic inputs and regulating lipid and glucose metabolism.
  • Publication
    Transient Receptor Potential-Vanilloid (TRPV1-TRPV4) Channels in the Atlantic Salmon, Salmo salar. A Focus on the Pineal Gland and Melatonin Production
    (Frontiers, 2022-01-07) Nisembaum, Laura Gabriela; Loentgen, Guillaume; L’Honoré, Thibaut; Martin, Patrick; Paulin, Charles-Hubert; Fuentès, Michael; Escoubeyrou, Karine; Delgado Saavedra, María Jesús; Besseau, Laurence; Falcón, Jack
    Fish are ectotherm, which rely on the external temperature to regulate their internal body temperature, although some may perform partial endothermy. Together with photoperiod, temperature oscillations, contribute to synchronizing the daily and seasonal variations of fish metabolism, physiology and behavior. Recent studies are shedding light on the mechanisms of temperature sensing and behavioral thermoregulation in fish. In particular, the role of some members of the transient receptor potential channels (TRP) is being gradually unraveled. The present study in the migratory Atlantic salmon, Salmo salar, aims at identifying the tissue distribution and abundance in mRNA corresponding to the TRP of the vanilloid subfamilies, TRPV1 and TRPV4, and at characterizing their putative role in the control of the temperature-dependent modulation of melatonin production—the time-keeping hormone—by the pineal gland. In Salmo salar, TRPV1 and TRPV4 mRNA tissue distribution appeared ubiquitous; mRNA abundance varied as a function of the month investigated. In situ hybridization and immunohistochemistry indicated specific labeling located in the photoreceptor cells of the pineal gland and the retina. Additionally, TRPV analogs modulated the production of melatonin by isolated pineal glands in culture. The TRPV1 agonist induced an inhibitory response at high concentrations, while evoking a bell-shaped response (stimulatory at low, and inhibitory at high, concentrations) when added with an antagonist. The TRPV4 agonist was stimulatory at the highest concentration used. Altogether, the present results agree with the known widespread distribution and role of TRPV1 and TRPV4 channels, and with published data on trout (Oncorhynchus mykiss), leading to suggest these channels mediate the effects of temperature on S. salar pineal melatonin production. We discuss their involvement in controlling the timing of daily and seasonal events in this migratory species, in the context of an increasing warming of water temperatures.
  • Publication
    Hypothalamic Integration of Metabolic, Endocrine, and Circadian Signals in Fish: Involvement in the Control of Food Intake
    (Frontiers Media, 2017-06) Delgado Saavedra, María Jesús; Cerdá Reverter, José M.; Soengas, José L.
    The regulation of food intake in fish is a complex process carried out through several different mechanisms in the central nervous system (CNS) with hypothalamus being the main regulatory center. As in mammals, a complex hypothalamic circuit including two populations of neurons: one co-expressing neuropeptide Y (NPY) and Agouti-related peptide (AgRP) and the second one population co-expressing pro-opiomelanocortin (POMC) and cocaine- and amphetamine-regulated transcript (CART) is involved in the integration of information relating to food intake control. The production and release of these peptides control food intake, and the production results from the integration of information of different nature such as levels of nutrients and hormones as well as circadian signals. The present review summarizes the knowledge and recent findings about the presence and functioning of these mechanisms in fish and their differences vs. the known mammalian model.
  • Publication
    First evidence of nocturnin in fish: two isoforms in goldfish differentially regulated by feeding
    (American Physiological Society, 2018-02) Blanco Imperiali, Ayelén M.; Gómez-Boronat, Miguel; Madera, Diego; Valenciano González, Ana Isabel; Alonso Gómez, Ángel Luis; Delgado Saavedra, María Jesús
    Nocturnin (NOC) is a unique deadenylase with robust rhythmic expression involved in the regulation of metabolic processes in mammals. Currently, the possible presence of NOC in fish is unknown. This report aimed to identify NOC in a fish model, the goldfish (Carassius auratus), and to study the possible regulation of its expression by feeding. Two partial-length cDNAs of 293 and 223 bp, named nocturnin-a (noc-a) and nocturnin-b (noc-b), were identified and found to be highly conserved among vertebrates. Both mRNAs show a similar widespread distribution in central and peripheral tissues, with higher levels detected for noc-a compared with noc-b. The periprandial expression profile revealed that noc-a mRNAs rise sharply after a meal in hypothalamus, intestinal bulb, and liver, whereas almost no changes were observed for noc-b. Food deprivation was found to exert opposite effects on the expression of both NOCs (generally inhibitory for noc-a, and stimulatory for noc-b) in the three mentioned tissues. A single meal after a 48-h food deprivation period reversed (totally or partially) the fasting-induced decreases in noc-a transcripts in all studied tissues and the increases in noc-b expression in the intestinal bulb. Together, this study offers the first report of NOC in fish and shows a high dependence of its expression on feeding and nutritional status. The differential responses to feeding of the two NOCs raise the possibility that they might be underlying different physiological mechanisms (e.g., food intake, lipid mobilization, energy homeostasis) in fish.
  • Publication
    Interplay between the endocrine and circadian systems in fishes
    (Bioscientifica, 2017-03) Isorna Alonso, Esther; Pedro Ormeño, Nuria de; Valenciano González, Ana Isabel; Alonso Gómez, Ángel Luis; Delgado Saavedra, María Jesús
    The circadian system is responsible for the temporal organisation of physiological functions which, in part, involves daily cycles of hormonal activity. In this review, we analyse the interplay between the circadian and endocrine systems in fishes. We first describe the current model of fish circadian system organisation and the basis of the molecular clockwork that enables different tissues to act as internal pacemakers. This system consists of a net of central and peripherally located oscillators and can be synchronised by the light–darkness and feeding–fasting cycles. We then focus on two central neuroendocrine transducers (melatonin and orexin) and three peripheral hormones (leptin, ghrelin and cortisol), which are involved in the synchronisation of the circadian system in mammals and/or energy status signalling. We review the role of each of these as overt rhythms (i.e. outputs of the circadian system) and, for the first time, as key internal temporal messengers that act as inputs for other endogenous oscillators. Based on acute changes in clock gene expression, we describe the currently accepted model of endogenous oscillator entrainment by the light–darkness cycle and propose a new model for non-photic (endocrine) entrainment, highlighting the importance of the bidirectional cross-talking between the endocrine and circadian systems in fishes. The flexibility of the fish circadian system combined with the absence of a master clock makes these vertebrates a very attractive model for studying communication among oscillators to drive functionally coordinated outputs.
  • Publication
    Brain transcriptome profile after CRISPR-induced ghrelin mutations in zebrafish
    (Springer, 2020-02) Blanco Imperiali, Ayelén M.; Cortés, Raul; Bertucci, Juan Ignacio; Sánchez, Elisa; Valenciano González, Ana Isabel; Cerdá-Reverter, José Miguel; Delgado Saavedra, María Jesús
    Ghrelin (GRL) is a gut-brain hormone with a role in a wide variety of physiological functions in mammals and fish, which points out the ghrelinergic system as a key element for the appropriate biological functioning of the organism. However, many aspects of the multifunctional nature of GRL remain to be better explored, especially in fish. In this study, we used the CRISPR/Cas9 genome editing technique to generate F0 zebrafish in which the expression of grl is compromised. Then, we employed high-throughput mRNA sequencing (RNA-seq) to explore changes in the brain transcriptome landscape associated with the silencing of grl. The CRISPR/Cas9 technique successfully edited the genome of F0 zebrafish resulting in individuals with considerably lower levels of GRL mRNAs and protein and ghrelin Oacyl transferase (goat) mRNAs in the brain, intestine, and liver compared to wild-type (WT) zebrafish. Analysis of brain transcriptome revealed a total of 1360 differentially expressed genes (DEGs) between the grl knockdown (KD) and WT zebrafish, with 664 up- and 696 downregulated DEGs in the KD group. Functional enrichment analysis revealed that DEGs are highly enriched for terms related to morphogenesis, metabolism (especially of lipids), entrainment of circadian clocks, oxygen transport, apoptosis, and response to stimulus. The present study offers valuable information on the central genes and pathways implicated in functions of GRL, and points out the possible involvement of this peptide in some novel functions in fish, such as apoptosis and oxygen transport.
  • Publication
    Two cholecystokinin receptor subtypes are identified in goldfish, being the CCKAR involved in the regulation of intestinal motility
    (Elsevier, 2015-09) Tinoco Pérez, Ana Belén; Valenciano González, Ana Isabel; Gómez Boronat, Miguel; Blanco, A.M.; Nisembaum, Laura Gabriela; Pedro Ormeño, Nuria de; Delgado Saavedra, María Jesús
    Cholecystokinin (CCK) plays a key role in the digestive physiology of vertebrates. However, very little is known about the role of CCK on intestinal functions in fish. The present study identifies two CCK receptor subtypes in a stomachless teleost, the goldfish (Carassius auratus), and investigates by using an in vitro system their involvement mediating the effects of the sulfated octapeptide of CCK (CCK-8S) on the motility of isolated proximal intestine. Partial-length mRNAs encoding two CCK receptor isoforms (CCKAR and CCKBR.I) were sequenced and the structural analysis showed that both receptors belong to the G-protein coupled receptor superfamily. Both gold- fish CCK receptor sequences were more closely related to zebrafish sequences, sharing the lowest similarities with cavefish and tilapia. The highest expression of goldfish CCKAR was observed along the whole intestine whereas the CCKBR gen was predominantly expressed in the hypothalamus, vagal lobe and posterior intestine. Application of CCK-8S to the organ bath evoked a concentration-dependent contractile response in intestine strips. The contractions were not blocked by either tetrodotoxin or atropine, suggesting that CCK-8S acts on the gut smooth muscle directly. Preincubations of intestine strips with devazepide and L365,260 (CCKAR and CCKBR receptor selective antagonists) showed that the CCK-8S-induced contraction could be partially mediated by the CCKAR receptor subtype, which is also the most abundant CCK receptor found in gastrointestinal tissues. In conclusion, two CCK receptors with a differential distribution pattern has been identified in goldfish, and the CCKAR subtype is mainly involved in the regulation of intestinal motility by the CCK-8S.