Biology subjects

Veron, V.

Publications and source records attributed to Veron, V..

5 recordsLinked to original sources

bioRxiv2024

Dissecting the nutritional regulations of a whole amino acid transporter family from a complex genome species: A holistic approach turning weaknesses into strengths

Amino acid transporters (AATs) are described as pivotal in maintaining circulating and cellular concentrations of AA via regulation of their expression in response to the cellular environment. Rainbow trout (RT), a complex genome species, is poorly described for AATs roles in controlling its predominant AA-based metabolism, despite representing a major challenge in the aquaculture nutrition field. Therefore, we identified the whole repertoire of AAT found in RT genome (>200), its expression in tissues and its nutritional regulations in vitro. Results garnered revealed the existence of different clusters of AATs, notably due to promoters bearing ATF4-related AA response elements. Moreover, the modeling of each AAT-specific cluster activities disclosed mTOR-related signaling functions of Ile and Phe, yet unknown in RT. Thus, this novel approach herein described should help to better grasp AA homeostasis in most organisms and topics such as fish nutrition and evolution.

cell biology↗

bioRxiv2024

The zebrafish as a new model for studying chaperone-mediated autophagy unveils its role in spermatogenesis

Chaperone-Mediated Autophagy (CMA) is a major pathway of lysosomal proteolysis involved in numerous cellular processes, and whose dysfunction is associated to several pathologies. Initially studied in mammals and birds, recent findings have identified CMA in fish, reshaping our understanding of its evolution across metazoans. Given the exciting perspectives this finding offered, we have now developed the required tools to investigate and functionally asses that CMA function in a powerful fish genetic model: the zebrafish (Danio rerio). After adapting and validating a fluorescent reporter (KFERQ-Dendra2; previously used to track CMA in mammalian cells) in zebrafish primary embryonic cells, we first demonstrated CMA functionality in this fish species. Then, we developed a transgenic zebrafish line expressing the KFERQ-Dendra2 CMA reporter, enabling the real-time tracking of CMA activity in vivo. This model revealed heterogeneous CMA responses within tissues, highlighting the zebrafish as a valuable model for investigating tissue-specific and cell-scale variations in CMA. Moreover, a novel role for CMA has been uncovered, acting as a gatekeeper of sperm cell proteostasis, thereby playing a crucial role in the production of active and high-quality spermatozoa. Overall, these findings emphasize the zebrafish as a pivotal model for advancing our comprehension of the fundamental mechanisms underlying CMA.

cell biology↗

bioRxiv2024

Chaperone-Mediated Autophagy in Fish: A Key Function Amid a Changing Environment

Chaperone-Mediated Autophagy (CMA) is a major pathway of lysosomal proteolysis critical for cellular homeostasis and metabolism. While extensively studied in mammals, CMAs existence in fish has only been confirmed recently, offering exciting insights into its role in species facing environmental stress. Here, we shed light on the existence of 2 genes encoding the CMA-limiting factor Lamp2A (lysosomal associated membrane protein 2A) in rainbow trout (RT, Oncorhynchus mykiss), revealing distinct expression patterns across various tissues. Notably, RT lacking the most expressed Lamp2A exhibit profound hepatic proteome disturbances during acute nutritional stress, underscoring its pivotal role as a guardian of hepatic proteostasis. Building upon these findings, we introduce and validate the CMA activation score as a reliable indicator of CMA status, providing a valuable tool for detecting cellular stress in fish under environmental threats. Overall, our study offers new perspectives into understanding CMA from evolutionary and environmental contexts. O_FIG O_LINKSMALLFIG WIDTH=200 HEIGHT=70 SRC="FIGDIR/small/585855v1_ufig1.gif" ALT="Figure 1"> View larger version (10K): org.highwire.dtl.DTLVardef@de3c56org.highwire.dtl.DTLVardef@4b711forg.highwire.dtl.DTLVardef@efb4a1org.highwire.dtl.DTLVardef@13be9cc_HPS_FORMAT_FIGEXP M_FIG C_FIG

cell biology↗

bioRxiv2023

High carbohydrate to protein ratio promotes changes in intestinal microbiota and host metabolism in rainbow trout (Oncorhynchus mykiss) fed plant-based diet.

To ensure the sustainability of aquaculture, it is necessary to change the "menu" of carnivorous fish such as rainbow trout from a fish-based diet to one with plant-based ingredients. However, there is a major problem with the growth performance decrease of fish fed with a 100% plant-based diet due to the reduction in feed intake and feed efficiency. For the first time, we incorporated high levels of digestible carbohydrates (high-starch diet) in a 100% plant-based diet during a 12-week feeding trial in order to improve protein utilization for growth (protein sparing effect) and reduce nitrogen waste. We measured the changes in the intestinal microbiota, Short-Chain Fatty Acid (SCFA) levels and metabolic responses in liver. Dietary carbohydrates had a strong effect on alpha and beta diversity and abundance of 12 genera, including Ralstonia and Bacillus in digesta associated microbiota whereas mucosa associated microbiota was less affected. The change in microbial diversity might be linked to the change observed in SCFA production. High levels of Mycoplasma were observed in the intestinal mucosa. Overall, hepatic gene expression was significantly altered by the CHO/protein ratio. Up-regulation of genes involved in glucose metabolism (gcka, gckb, g6pcb2a), down-regulation of genes involved in lipid metabolism (hadh, acox3, srebp2a, and cyp51a) were associated with higher enzymatic activities (such as glucokinase or pyruvate kinase) and higher glycogen levels in the liver, suggesting adequate adaptation to diet. Interestingly, strong correlations were observed between abundances of certain bacterial OTUs and gene expression in the liver. The inclusion of digestible carbohydrates in combination with a 100% plant-based diet, could be a promising way to improve and reduce the use of plant proteins in rainbow trout. In addition, the relationship between intestinal microbiota and host metabolism needs further investigation to better understand fish nutrition.

molecular biology↗

bioRxiv2023

Rainbow trout neomales broodstocks are able to eat and use a high carbohydrate diet during a complete reproductive cycle

The main challenge of the aquaculture relies on the shift from fishmeal to more sustainable ingredients. Interest on carbohydrates has growing rapidly as they are considered as promising resources, providing energy and preserving proteins for growth. However, rainbow trout is considered as a poor user of carbohydrates displaying postprandial hyperglycaemia and impaired growth performances when fed with diets containing more than 20% of carbohydrates. Nonetheless, recent evidence points that broodstocks could be better user of high carbohydrate diet compared to juveniles. However, no study investigates how sex-reversed females - neomales - eat, grow and reproduce under a high carbohydrate diet. Our objective was thus to assess growth and reproductive performances of neomales fed with a high carbohydrate diet during an entire reproductive cycle. Our results demonstrate that neomales display specific metabolic and physiological changes when fed with a high carbohydrate diet compared to both females and males broodstocks as well as compared to juveniles. Altogether, our data demonstrate the critical relevance to formulate specific diets in accordance with specificities of each type of broodstocks (i.e. females, males and neomales).

molecular biology↗