American Journal of Physiology-Regulatory, Integrative and Comparative Physiology, 2011
The insulin-like growth factor-I (IGF-I) is a key regulator of skeletal muscle growth in vertebra... more The insulin-like growth factor-I (IGF-I) is a key regulator of skeletal muscle growth in vertebrates, promoting mitogenic and anabolic effects through the activation of the MAPK/ERK and the PI3K/Akt signaling pathways. Nutrition also affects skeletal muscle growth, activating intracellular pathways and inducing protein synthesis and accretion. Thus, both hormonal and nutritional signaling regulate muscle mass. In this context, plasma IGF-I levels and the activation of both pathways in response to food were evaluated in the fine flounder using fasting and refeeding trials. The present study describes for the first time in a nonmammalian species that the MAPK/ERK and PI3K/Akt are activated by exogenous circulating IGF-I, as well as showing that the MAPK/ERK pathway activation is modulated by the nutritional status. Also, these results show that there is a time-dependent regulation of IGF-I plasma levels and its signaling pathways in muscle. Together, these results suggest that the nut...
Edible red sea urchin (Loxechinus albus) is an endemic echinoderm species of the Chilean coasts. ... more Edible red sea urchin (Loxechinus albus) is an endemic echinoderm species of the Chilean coasts. The worldwide demand for high-quality gonads of this species has addressed the depletion of its natural populations. Studies on this sea urchin are limited, and genomic information is almost nonexistent. Hence, generate a transcriptome is crucial information that will considerably enrich molecular data and promote future findings for the L. albus aquaculture. Here, we obtained transcriptomic data of the edible red sea urchin by Illumina platform. Total RNA was extracted from gonads, intestines, and coelomocytes of juvenile urchins, and samples were sequenced using MiSeq Illumina technology. A total of 91,119,300 paired-end reads were de novo assembled, 185,239 transcripts produced, and a reference transcriptome created with 38.8% GC content and an N50 of 1769 bp. Gene ontology analysis revealed notable differences in the expression profiles between gonads, intestines, and coelomocytes, a...
Background Skeletal muscle is one of the tissues most affected by stress conditions. The protein ... more Background Skeletal muscle is one of the tissues most affected by stress conditions. The protein degradation in this tissue is vital for the supply of energy mediated by different proteolytic pathways such as the ubiquitin-proteasome (UPS), autophagy-lysosome (ALS) and the calpain/calpastatin system (CCS). Nevertheless, the regulation of this proteolytic axis under stress conditions is not yet completely clear. Chile is the main producer of rainbow trout (Oncorhynchus mykiss) in the world. This intensive fish farming has resulted in growing problems as crowding and stress are one of the major problems in the freshwater stage. In this context, we evaluated the crowding effect in juvenile rainbow trout kept in high stocking density (30 kg/m3) for 15, 45 and 60 days, using a control group of fish (10 kg/m3). Results Plasmatic cortisol and glucose were evaluated by enzyme immunoassay. The mRNA levels of stress-related genes (gr1, gr2, mr, hsp70, klf15 and redd1), markers of the UPS (atr...
American journal of physiology. Regulatory, integrative and comparative physiology, Jan 4, 2017
Chronic stress detrimentally affects animal health and homeostasis, with somatic growth, and thus... more Chronic stress detrimentally affects animal health and homeostasis, with somatic growth, and thus skeletal muscle, being particularly affected. A detailed understanding of the underlying endocrine and molecular mechanisms of how chronic stress affects skeletal muscle growth remains lacking. To address this issue, the present study assessed primary (plasma cortisol), secondary (key components of the GH/IGF system, muscular proteolytic pathways and apoptosis), and tertiary (growth performance) stress responses in fine flounder (Paralichthys adspersus) exposed to crowding chronic stress. Levels of plasma cortisol, glucocorticoid receptor 2 (gr2), and its target genes (klf15 and redd1) mRNA increased significantly only at 4wk of crowding (p<0.05). The components of the GH/IGF system, including ligands, receptors, and their signaling pathways, were significantly downregulated at 7wk of crowding (p<0.05). Interestingly, chronic stress upregulated the ubiquitin-proteasome pathway and...
Comparative Biochemistry and Physiology Part B: Biochemistry and Molecular Biology
Growth is one of the main biological processes in aquatic organisms that is affected by environme... more Growth is one of the main biological processes in aquatic organisms that is affected by environmental fluctuations such as upwelling (characterized by food-rich waters). In fish, growth is directly related with skeletal muscle increase; which represents the largest tissue of body mass. However, the effects of upwelling on growth, at the physiological and molecular level, are unknown. This study used Girella laevifrons (one of the most abundant intertidal fish in Eastern South Pacific) as a biological model, considering animals from upwelling (U) and non-upwelling (NU) areas. Here, we evaluated the effect of nutritional composition and food availability on growth performance and expression of key growth-related genes (insulin-kike growth factor 1 (igf1) and myosin heavy-chain (myhc)) and atrophy-related genes (muscle ring-finger 1 (murf1), F-box only protein 32 (atrogin-1) and BCL2/adenovirus E1B 19kDa-interacting protein 3 (bnip3)). We reported that, among zones, U fish displayed higher growth performance in response to nutritional composition, specifically between protein- and fiber-rich diets (~1g). We also found in NU fish that atrophy-related genes were upregulated with fiber-rich diet and during fasting (~2-fold at minimum respect U). In conclusion, our results suggest that the growth potential of upwelling fish may be a consequence of differential muscle gene expression. Our data provide a preliminary approach contributing on how upwelling influence fish growth at the physiological and molecular levels. Future studies are required to gain further knowledge about molecular differences between U and NU animals, as well as the possible applications of this knowledge in the aquaculture industry.
Teleosts exhibit a broad divergence in their adaptive response to stress, depending on the magnit... more Teleosts exhibit a broad divergence in their adaptive response to stress, depending on the magnitude, duration, and frequency of stressors and the species receiving the stimulus. We have previously reported that the red cusk-eel (Genypterus chilensis), an important marine farmed fish, shows a physiological response to stress that results in increased skeletal muscle atrophy mediated by over-expression of components of the ubiquitin proteasome and autophagy-lysosomal systems. To better understand the systemic effects of stress on the red cusk-eel metabolism, the present study assessed the transcriptomic hepatic response to repetitive handling-stress. Using high-throughput RNA-seq, 259 up-regulated transcripts were found, mostly associated with angiogenesis, gluconeogenesis, and triacylglyceride catabolism. Conversely, 293 transcripts were down-regulated, associated to cholesterol biosynthesis, PPARα signaling, fatty acid biosynthesis, and glycolysis. This gene signature was concordan...
Cortisol is an essential regulator of neuroendocrine stress responses in teleosts. Cortisol predo... more Cortisol is an essential regulator of neuroendocrine stress responses in teleosts. Cortisol predominantly affects target tissues through the genomic pathway, which involves interacting with cytoplasmic glucocorticoid receptors and, thereby, modulating stress-response gene expressions. Cortisol also produces rapid effects via non-genomic pathways, which do not involve gene transcription. Although cortisol-mediated genomic pathways are well documented in teleosts, non-genomic pathways are not fully understood. Moreover, no studies have focused on the contribution of non-genomic cortisol pathways in compensatory stress responses in fish. In this study, rainbow trout (Oncorhynchus mykiss) skeletal myotubes were stimulated with physiological concentrations of cortisol and cortisol-BSA, a membrane-impermeable agent, resulting in an early induction of reactive oxygen species (ROS). This production was not suppressed by transcription or translation inhibitors, suggesting non-genomic pathway...
Background: Fish reared under intensive conditions are repeatedly exposed to stress, which negati... more Background: Fish reared under intensive conditions are repeatedly exposed to stress, which negatively impacts growth. Although most fish follow a conserved pattern of stress response, with increased concentrations of cortisol, each species presents specificities in the cell response and stress tolerance. Therefore, culturing new species requires a detailed knowledge of these specific responses. The red cusk-eel (Genypterus chilensis) is a new economically important marine species for the Chilean aquaculture industry. However, there is no information on the stress-and cortisol-induced mechanisms that decrease skeletal muscle growth in this teleost. Results: Using Illumina RNA-seq technology, skeletal muscle sequence reads for G. chilensis were generated under control and handling stress conditions. Reads were mapped onto a reference transcriptome, resulting in the in silico identification of 785 up-regulated and 167 down-regulated transcripts. Gene ontology enrichment analysis revealed a significant upregulation of catabolic genes associated with skeletal muscle atrophy. These results were validated by RT-qPCR analysis for ten candidates genes involved in ubiquitin-mediated proteolysis, autophagy and skeletal muscle growth. Additionally, using a primary culture of fish skeletal muscle cells, the effect of cortisol was evaluated in relation to red cusk-eel skeletal muscle atrophy. Conclusions: The present data demonstrated that handling stress promotes skeletal muscle atrophy in the marine teleost G. chilensis through the expression of components of the ubiquitin-proteasome and autophagy-lysosome systems. Furthermore, cortisol was a powerful inductor of skeletal muscle atrophy in fish myotubes. This study is an important step towards understanding the atrophy system in non-model teleost species and provides novel insights on the cellular and molecular mechanisms that control skeletal muscle growth in early vertebrates.
... Norman Maclean, Gyulin Hwang, Alfredo Molina, Tom Ashton, Marc Muller, M. Aziz Rahman, and Ar... more ... Norman Maclean, Gyulin Hwang, Alfredo Molina, Tom Ashton, Marc Muller, M. Aziz Rahman, and Arati Iyengar ... fish have been produced by triploid induction3, but in species such as tilapia this is quite difficult and the all-female triploid technology used with success in salmon ...
American Journal of Physiology-Regulatory, Integrative and Comparative Physiology, 2011
The insulin-like growth factor-I (IGF-I) is a key regulator of skeletal muscle growth in vertebra... more The insulin-like growth factor-I (IGF-I) is a key regulator of skeletal muscle growth in vertebrates, promoting mitogenic and anabolic effects through the activation of the MAPK/ERK and the PI3K/Akt signaling pathways. Nutrition also affects skeletal muscle growth, activating intracellular pathways and inducing protein synthesis and accretion. Thus, both hormonal and nutritional signaling regulate muscle mass. In this context, plasma IGF-I levels and the activation of both pathways in response to food were evaluated in the fine flounder using fasting and refeeding trials. The present study describes for the first time in a nonmammalian species that the MAPK/ERK and PI3K/Akt are activated by exogenous circulating IGF-I, as well as showing that the MAPK/ERK pathway activation is modulated by the nutritional status. Also, these results show that there is a time-dependent regulation of IGF-I plasma levels and its signaling pathways in muscle. Together, these results suggest that the nut...
Edible red sea urchin (Loxechinus albus) is an endemic echinoderm species of the Chilean coasts. ... more Edible red sea urchin (Loxechinus albus) is an endemic echinoderm species of the Chilean coasts. The worldwide demand for high-quality gonads of this species has addressed the depletion of its natural populations. Studies on this sea urchin are limited, and genomic information is almost nonexistent. Hence, generate a transcriptome is crucial information that will considerably enrich molecular data and promote future findings for the L. albus aquaculture. Here, we obtained transcriptomic data of the edible red sea urchin by Illumina platform. Total RNA was extracted from gonads, intestines, and coelomocytes of juvenile urchins, and samples were sequenced using MiSeq Illumina technology. A total of 91,119,300 paired-end reads were de novo assembled, 185,239 transcripts produced, and a reference transcriptome created with 38.8% GC content and an N50 of 1769 bp. Gene ontology analysis revealed notable differences in the expression profiles between gonads, intestines, and coelomocytes, a...
Background Skeletal muscle is one of the tissues most affected by stress conditions. The protein ... more Background Skeletal muscle is one of the tissues most affected by stress conditions. The protein degradation in this tissue is vital for the supply of energy mediated by different proteolytic pathways such as the ubiquitin-proteasome (UPS), autophagy-lysosome (ALS) and the calpain/calpastatin system (CCS). Nevertheless, the regulation of this proteolytic axis under stress conditions is not yet completely clear. Chile is the main producer of rainbow trout (Oncorhynchus mykiss) in the world. This intensive fish farming has resulted in growing problems as crowding and stress are one of the major problems in the freshwater stage. In this context, we evaluated the crowding effect in juvenile rainbow trout kept in high stocking density (30 kg/m3) for 15, 45 and 60 days, using a control group of fish (10 kg/m3). Results Plasmatic cortisol and glucose were evaluated by enzyme immunoassay. The mRNA levels of stress-related genes (gr1, gr2, mr, hsp70, klf15 and redd1), markers of the UPS (atr...
American journal of physiology. Regulatory, integrative and comparative physiology, Jan 4, 2017
Chronic stress detrimentally affects animal health and homeostasis, with somatic growth, and thus... more Chronic stress detrimentally affects animal health and homeostasis, with somatic growth, and thus skeletal muscle, being particularly affected. A detailed understanding of the underlying endocrine and molecular mechanisms of how chronic stress affects skeletal muscle growth remains lacking. To address this issue, the present study assessed primary (plasma cortisol), secondary (key components of the GH/IGF system, muscular proteolytic pathways and apoptosis), and tertiary (growth performance) stress responses in fine flounder (Paralichthys adspersus) exposed to crowding chronic stress. Levels of plasma cortisol, glucocorticoid receptor 2 (gr2), and its target genes (klf15 and redd1) mRNA increased significantly only at 4wk of crowding (p<0.05). The components of the GH/IGF system, including ligands, receptors, and their signaling pathways, were significantly downregulated at 7wk of crowding (p<0.05). Interestingly, chronic stress upregulated the ubiquitin-proteasome pathway and...
Comparative Biochemistry and Physiology Part B: Biochemistry and Molecular Biology
Growth is one of the main biological processes in aquatic organisms that is affected by environme... more Growth is one of the main biological processes in aquatic organisms that is affected by environmental fluctuations such as upwelling (characterized by food-rich waters). In fish, growth is directly related with skeletal muscle increase; which represents the largest tissue of body mass. However, the effects of upwelling on growth, at the physiological and molecular level, are unknown. This study used Girella laevifrons (one of the most abundant intertidal fish in Eastern South Pacific) as a biological model, considering animals from upwelling (U) and non-upwelling (NU) areas. Here, we evaluated the effect of nutritional composition and food availability on growth performance and expression of key growth-related genes (insulin-kike growth factor 1 (igf1) and myosin heavy-chain (myhc)) and atrophy-related genes (muscle ring-finger 1 (murf1), F-box only protein 32 (atrogin-1) and BCL2/adenovirus E1B 19kDa-interacting protein 3 (bnip3)). We reported that, among zones, U fish displayed higher growth performance in response to nutritional composition, specifically between protein- and fiber-rich diets (~1g). We also found in NU fish that atrophy-related genes were upregulated with fiber-rich diet and during fasting (~2-fold at minimum respect U). In conclusion, our results suggest that the growth potential of upwelling fish may be a consequence of differential muscle gene expression. Our data provide a preliminary approach contributing on how upwelling influence fish growth at the physiological and molecular levels. Future studies are required to gain further knowledge about molecular differences between U and NU animals, as well as the possible applications of this knowledge in the aquaculture industry.
Teleosts exhibit a broad divergence in their adaptive response to stress, depending on the magnit... more Teleosts exhibit a broad divergence in their adaptive response to stress, depending on the magnitude, duration, and frequency of stressors and the species receiving the stimulus. We have previously reported that the red cusk-eel (Genypterus chilensis), an important marine farmed fish, shows a physiological response to stress that results in increased skeletal muscle atrophy mediated by over-expression of components of the ubiquitin proteasome and autophagy-lysosomal systems. To better understand the systemic effects of stress on the red cusk-eel metabolism, the present study assessed the transcriptomic hepatic response to repetitive handling-stress. Using high-throughput RNA-seq, 259 up-regulated transcripts were found, mostly associated with angiogenesis, gluconeogenesis, and triacylglyceride catabolism. Conversely, 293 transcripts were down-regulated, associated to cholesterol biosynthesis, PPARα signaling, fatty acid biosynthesis, and glycolysis. This gene signature was concordan...
Cortisol is an essential regulator of neuroendocrine stress responses in teleosts. Cortisol predo... more Cortisol is an essential regulator of neuroendocrine stress responses in teleosts. Cortisol predominantly affects target tissues through the genomic pathway, which involves interacting with cytoplasmic glucocorticoid receptors and, thereby, modulating stress-response gene expressions. Cortisol also produces rapid effects via non-genomic pathways, which do not involve gene transcription. Although cortisol-mediated genomic pathways are well documented in teleosts, non-genomic pathways are not fully understood. Moreover, no studies have focused on the contribution of non-genomic cortisol pathways in compensatory stress responses in fish. In this study, rainbow trout (Oncorhynchus mykiss) skeletal myotubes were stimulated with physiological concentrations of cortisol and cortisol-BSA, a membrane-impermeable agent, resulting in an early induction of reactive oxygen species (ROS). This production was not suppressed by transcription or translation inhibitors, suggesting non-genomic pathway...
Background: Fish reared under intensive conditions are repeatedly exposed to stress, which negati... more Background: Fish reared under intensive conditions are repeatedly exposed to stress, which negatively impacts growth. Although most fish follow a conserved pattern of stress response, with increased concentrations of cortisol, each species presents specificities in the cell response and stress tolerance. Therefore, culturing new species requires a detailed knowledge of these specific responses. The red cusk-eel (Genypterus chilensis) is a new economically important marine species for the Chilean aquaculture industry. However, there is no information on the stress-and cortisol-induced mechanisms that decrease skeletal muscle growth in this teleost. Results: Using Illumina RNA-seq technology, skeletal muscle sequence reads for G. chilensis were generated under control and handling stress conditions. Reads were mapped onto a reference transcriptome, resulting in the in silico identification of 785 up-regulated and 167 down-regulated transcripts. Gene ontology enrichment analysis revealed a significant upregulation of catabolic genes associated with skeletal muscle atrophy. These results were validated by RT-qPCR analysis for ten candidates genes involved in ubiquitin-mediated proteolysis, autophagy and skeletal muscle growth. Additionally, using a primary culture of fish skeletal muscle cells, the effect of cortisol was evaluated in relation to red cusk-eel skeletal muscle atrophy. Conclusions: The present data demonstrated that handling stress promotes skeletal muscle atrophy in the marine teleost G. chilensis through the expression of components of the ubiquitin-proteasome and autophagy-lysosome systems. Furthermore, cortisol was a powerful inductor of skeletal muscle atrophy in fish myotubes. This study is an important step towards understanding the atrophy system in non-model teleost species and provides novel insights on the cellular and molecular mechanisms that control skeletal muscle growth in early vertebrates.
... Norman Maclean, Gyulin Hwang, Alfredo Molina, Tom Ashton, Marc Muller, M. Aziz Rahman, and Ar... more ... Norman Maclean, Gyulin Hwang, Alfredo Molina, Tom Ashton, Marc Muller, M. Aziz Rahman, and Arati Iyengar ... fish have been produced by triploid induction3, but in species such as tilapia this is quite difficult and the all-female triploid technology used with success in salmon ...
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