Biology subjects

Velez, E. J.

Publications and source records attributed to Velez, E. J..

3 recordsLinked to original sources

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↗

bioRxiv2024

Nucleobindin-1 (Nucb1) disruption affects feeding, metabolism, and glucose homeostasis in mice in an age-, sex-, diet- and light cycle-dependent manner

BackgroundNesfatin-1 (NESF-1), encoded in the calcium and DNA binding protein (Nucleobindin 2, NUCB2) is an orphan ligand with metabolic effects. Recently, our lab provided evidence for a NESF-1-like peptide (NLP) in a NUCB2-related precursor, NUCB1, in zebrafish and rodents. This research aims to determine whether endogenous NUCB1 is critical for energy homeostasis. Methods and Main FindingsGlobal genetic disruption of Nucb1 (Nucb1 knockout/KO mice) led to increased food intake in chow-fed male and female mice across different points of light and dark phases. A similar increase in water intake was seen in female Nucb1 KO mice but not in males. White adipose tissue weight was significantly increased in male and female Nucb1 KO mice. Dark phase total activity was increased in male Nucb1 KO mice, while it was decreased in female Nucb1 KO mice compared to wildtype littermates. Energy derived from carbohydrates was raised during the dark phase; while energy derived from fat was significantly decreased in both male and female Nucb1 KO mice. Male Nucb1 KO mice were lighter in the early stages, but these differences disappeared as they aged. Meanwhile, no differences in bodyweight were observed in female Nucb1 KO mice. Male Nucb1 KO mice handled glucose better during an oral glucose tolerance test, while the opposite effect was found in an intraperitoneal (IP) glucose tolerance test. The above results from chow-fed mice were largely true in 10% and 60% fat diet-fed mice. A significant two-way interaction between mice group and time was observed on weekly food intake of male and female Nucb1 KO mice fed control fat diet, but not in 60% fat-fed group. Handling of blood glucose during IPGTT was better in male Nucb1 KO mice fed both diets, while such an effect was not observed in female KO mice. A significant two-way interaction of mice group and time on food and water intake value in 24 h was observed for male Nucb1 KO mice fed 10% fat diet. The total physical activity during the dark phase and energy expenditure during the light phase showed a sex-specific pattern in male and female Nucb1 KO mice fed 10% fat diet. Energy expenditure showed a sex-specific pattern in Nucb1 KO mice during the dark phase. Moreover, adiposity increased in male Nucb1 KO mice fed a high fat diet. ConclusionsOur results indicate that the disruption of Nucb1 leads to metabolic changes in vivo. The phenotype appears to depend on sex, age, diet, and the light-dark cycle. In conclusion, these outcomes furnish important evidence supporting critical roles for endogenous NUCB1 in energy homeostasis.

physiology↗