Biology subjects

Rodriguez-Palero, M. J.

Publications and source records attributed to Rodriguez-Palero, M. J..

4 recordsLinked to original sources

bioRxiv2025

Mitochondrial redox homeostasis links organellar stress surveillance to germline and somatic integrity in Caenorhabditis elegans

Mitochondrial redox homeostasis is essential for cellular metabolism and organismal development. To investigate the consequences of disrupting redox homeostasis in this organelle in a metazoan organism, we generated a double mutant lacking mitochondrial glutathione reductase (gsr-1a) and thioredoxin reductase (trxr-2) genes in Caenorhabditis elegans. While gsr-1a or trxr-2 single mutants are phenotypically normal, double gsr-1a trxr-2 mutants displayed small body size, gonadal migration defects, reduced brood size, and prolonged egg-laying period, without developmental delay or lethality. Transcriptomic analysis revealed strong induction of ATFS-1-dependent stress and detoxification genes. Consistent with this, gsr-1a trxr-2 worms exhibited constitutive ATFS-1 nuclear localization and robust Phsp-6::gfp expression. Triple gsr-1a trxr-2; atfs-1 mutants were nonviable, demonstrating that unfolded protein response (UPRmt) activation is essential under mitochondrial redox stress. Despite the induction of a stress response at the transcriptional level, gsr-1a trxr-2 double mutants were not more resistant to oxidative or pathogen stressors. Moreover, these mutants maintained normal respiration, ATP and ROS production while displaying altered mitochondrial morphology in a tissue-specific manner, independent of mitophagy genes but dependent on mitochondrial fission or fusion machinery. Functionally, gsr-1a trxr-2 mutants showed impaired motility, reduced calcium uptake upon carbachol stimulation, enhanced hypodermal wound repair, and decreased fertilization efficiency associated with lower muscle exopher production. Overall, our data show that simultaneous loss of mitochondrial GSR-1a and TRXR-2 compromises growth, fertility and muscle performance and triggers a constitutive ATFS-1-dependent UPRmt that sustains viability revealing mitochondrial redox control as a core determinant of organismal proteostasis. HighlightsO_LIgsr-1a or trxr-2 single mutants have no overt phenotypes. C_LIO_LIgsr-1a trxr-2 double mutants are viable but show small size, gonad migration defects and reduced progeny. C_LIO_LILoss of both reductases in mitochondria triggers a constitutive ATFS-1-dependent UPRmt. C_LIO_LIATFS-1 is essential for gsr-1a trxr-2 worms survival. C_LIO_LIgsr-1a trxr-2 animals remodel mitochondrial morphology in a tissue-specific manner. C_LIO_LIgsr-1a trxr-2 double mutants exhibit impaired muscle and sperm function but enhanced wound healing. C_LI Graphical abstract (to be incorporated)

genetics↗

bioRxiv2020

Social chemical communication determines recovery from L1 arrest via DAF-16 activation

In a population, chemical communication determines the response of animals to changing environmental conditions, what leads to an enhanced resistance against stressors. In response to starvation, the nematode Caenorhabditis elegans arrest post-embryonic development as L1 larva right after hatching. As arrested L1 larvae, C. elegans become more resistant to diverse stresses, allowing them to survive for several weeks expecting to encounter more favorable conditions. However, prolonged periods in L1 arrest lead to the accumulation of detrimental signs of aging, which ultimately provoke animal death. When arrested L1s feed, they undergo a recovery process to erase these harmful signs before resuming the developmental program. L1 arrested larvae secrete unidentified soluble compounds that improve survival to starvation. This protection is proportional to larval population density. Thus, animals arrested at high densities display an enhanced resistance to starvation. Here we show that this chemical communication also influences recovery after prolonged periods in L1 arrest. Animals at high density recovered faster than animals at low density. We found that the density effect on survival depends on the final effector of the insulin signaling pathway, the transcription factor DAF-16. Moreover, DAF-16 activation was higher at high density, consistent with a lower expression of the insulin-like peptide DAF-28 in the neurons. The improved recovery of animals after arrest at high density depended on soluble compounds present in the media of arrested L1s. In a try to find the nature of these compounds, we investigated the disaccharide trehalose as putative signaling molecule, since its production is enhanced during L1 arrest and it is able to activate DAF-16. We detected the presence of secreted trehalose in the medium of arrested L1 larvae at a low concentration. The addition of this concentration of trehalose to animals arrested at low density was enough to rescue DAF-28 production and DAF-16 activation to the levels of animals arrested at high density. However, despite activating DAF-16, trehalose was not capable of reversing survival and recovery phenotypes, suggesting the participation of additional signaling molecules. We finally identified GUR-3 as a possible trehalose receptor in C. elegans. With all, here we describe a molecular mechanism underlying social communication that allows C. elegans to maintain arrested L1 larvae ready to quickly recover as soon as they encounter nutrient sources.

developmental biology↗

bioRxiv2019

Prohibitin depletion suppresses mitochondrial, lipogenic and autophagic defects of SGK-1 mutant extending lifespan; implication of autophagy and the UPRmt

Mitochondrial prohibitins (PHB) are highly conserved proteins with a peculiar effect on lifespan. While PHB depletion shortens lifespan of wild type animals, it enhances longevity of a plethora of metabolically compromised mutants, including target of rapamycin complex 2 (TORC2) mutants sgk-1 and rict-1. Here, we show that sgk-1 mutants have impaired mitochondrial homeostasis, lipogenesis, yolk formation and autophagy flux due to alterations in membrane lipid and sterol homeostasis. Remarkably, all these features are suppressed by PHB depletion. Lifespan analysis shows that autophagy and the mitochondrial unfolded protein response (UPRmt), but not mitophagy, are required for the enhanced longevity caused by PHB depletion in sgk-1 mutants. We hypothesize that UPRmt induction upon PHB depletion extends lifespan of sgk-1 mutants through autophagy. Our results strongly suggest that PHB depletion suppresses the autophagy defects of sgk-1 mutants by altering membrane lipid composition at ER-mitochondria contact sites, where TORC2 localizes.

cell biology↗

bioRxiv2017

Combined flow cytometry and high throughput image analysis for the study of essential genes in Caenorhabditis elegans

BackgroundThe advancement in automated image based microscopy platforms coupled with high throughput liquid workflows has facilitated the design of large scale screens utilizing multicellular model organisms such as Caenorhabditis elegans to identify genetic interactions, therapeutic drugs or disease modifiers. However, the analysis of essential genes has lagged behind because lethal or sterile mutations pose a bottleneck for high throughput approaches.\n\nResultsIn C. elegans, non-conditional lethal mutations can be maintained in heterozygosis using chromosome balancers, commonly labelled with GFP in the pharynx. Moreover gene-expression is typically monitored by the use of fluorescent reporters marked with the same fluorophore. Therefore, the separation of the different populations of animals at early larval stages represents a challenge. Here, we develop a sorting strategy capable of selecting homozygous mutants carrying a GFP stress reporter from GFP-balanced animals at early larval stages. Because sorting is not completely error-free, we develop an automated high-throughput image-analysis protocol that identifies and discards animals carrying the chromosome balancer. We demonstrate the experimental usefulness of combining sorting of homozygous lethal mutants and automated image-analysis in a functional genomic RNAi screen for genes that genetically interact with mitochondrial prohibitin (PHB). Lack of PHB results in embryonic lethality, while, homozygous PHB deletion mutants develop into sterile adults due to maternal contribution and strongly induce the mitochondrial unfolded protein response (UPRmt). In a chromosome-wide RNAi screen for C. elegans genes having human orthologues, we uncover both, known and new PHB genetic interactors affecting the UPRmt and growth.\n\nConclusionsA systematic way to analyse genetic interactions of essential genes in multicellular organisms is lacking. The method presented here allows the study of balanced lethal mutations in a high-throughput manner and can be easily adapted depending on the users requirements. Therefore, it will serve as a useful resource for the C. elegans community for probing new biological aspects of essential nematode genes as well as the generation of more comprehensive genetic networks.

genetics↗