Maria Martinez-Iniesta et al. (2008) European Worm Meeting "Identification of response and resistance genes to 5-fluroracil (5-FU) in Caenorhabditis elegans."

Maria Martinez-Iniesta, Xavi Sole, Nuria Baixeras, Alberto Villanueva, Laura Padulles, Ramon Salazar, Victor Moreno, J Ramon Germa, Gabriel Capella

[European Worm Meeting, 2008]

Introduction: Colorectal cancer (CRC) is one of the leading causes of. cancer-related mortality in the Western world. In Spain is the second type. of cancer in incidence and mortality in both sexes and 50% of total. diagnostic cases death. Despite the improvement of diagnostic and treatment. only a few decreases have been observed. About 60% of all patients. diagnosed with CRC will present localized disease, being the surgery the. mainstay therapy. The rest of patients (Duke''s C and D) are diagnosed with. distal metastasis. 5-FU and oxaliplatin based chemotherapy (QT) are the. base of the standard treatment of colorectal cancer patients in both. adjuvant and metastasic setting. Initially, more patients did not respond. to QT treatments and others relapse after a short period of response. In. spite of the clinical relevance of 5-FU, little is known about the. mechanisms of resistance to this drug commonly observed in colorectal. cancer patients. Aim: To identify the genes involved in the mechanism of. resistance to 5-FU in the pluricellular model organisms Caenorhabditis. elegans (C.elegans), and posterior validation of these genes as a markers. of response/sensitivity to 5-FU chemotherapy treatments in tumor series.. Methods and Results: A 5-FU plate toxicity assay has been established. We. are characterizing the ceTS-1 gene, C.elegans homolog of human thymidylate. synthase gene, and temporal and cellular expression patterns during. development are studying in GFP transgenic worms. Different alternative. splicing isoforms are generating in CeTS-1 with unknown biological. implications that we are evaluating. Different phenotypes have been. associated with the worm 5-FU treatment. N2 wild-type worms and cib-1(e300). mutant, harboring a point mutation in Thymidilate Synthase gene (Schnabel. R), were synchronized, and both strains of worms were growth at different. drug concentrations and at different times. Profiles of 5-FU response are. being determined in C.elegans Affymetrix microarrays. To identify response. genes (we expected around 100-150 genes) we are performing a feeding double-. stranded RNA-mediated interference (dsRNAi) screening for response genes.. Conclusions: Identification in C. elegans of genes involved in the. resistance/sensitivity to 5-FU drug and later validation of their. predictive value of response in colorectal cancer series may permit to. dispose of the some genetic markers that finally can improve the CRC. patient treatment.. avillanueva@iconcologia.net

Katz, Menachem et al. (2013) International Worm Meeting "CEPsh glia modulate a sleep-related neuronal circuit in C. elegans."

Dragomir, Elena, Biron, David, Iwanir, Shachar, Corson, Francis, Shaham, Shai, Katz, Menachem

[International Worm Meeting, 2013]

Glia are essential components of the nervous system. However, their precise roles in the regulation of neuronal circuit activities and animal behavior are poorly understood. In 1895, Ramon y Cajal postulated that astrocytes regulate the transition between sleep and waking states. Remarkably, recent studies in mice and flies hint that Cajal's ideas may be more than theoretical musings. Yet, the mechanisms by which glia influence sleep are not fully resolved. Sleep in C. elegans is defined by behavioral lethargy that coincides with molting, linking development and locomotion. The CEPsh glia, which envelope the C. elegans nerve ring, are reminiscent of astrocytes, and extend processes that abut specific nerve-ring synapses. L1 ablation of CEPsh glia results in molting-independent short duration locomotory pausing, episodes of longer immobility immediately preceding molting, and developmental delay. The ALA neuron was previously implicated in sleep control. Interestingly, synapses between ALA and the backward command interneuron AVE are ensheathed by CEPsh glia, suggesting functional roles for these glia in modulating ALA-AVE synaptic activity. Indeed, loss of ALA function suppresses the locomotory defects, developmental delay, and precocious lethargus of CEPsh glia-ablated animals. Furthermore, inactivation of AVE in adults induces pausing reminiscent of CEPsh ablation. In animals lacking CEPsh glia, the duration of spontaneous calcium transients in AVE is prolonged and calcium spikes are decorrelated from backward locomotion. Correlation is restored upon ALA inactivation. These results as well as our functional epistasis studies of ALA, AVE and CEPsh glia are consistent with a model in which glia attenuate a sleep-promoting inhibitory connection between ALA and AVE. We propose that glia play key roles in C. elegans sleep control and that this role may be conserved.

Butler, V.J. et al. (2017) International Worm Meeting "A novel stress and age-responsive lysosomal protease inhibitor affecting proteostasis in neurodegeneration."

Ashrafi, K., Chand, S., Miller, B.L., Jacobson, M.P., Gao, F., Pierce, O.M., Coppola, G., Butler, V.J., Caballero, B., Oses-Prieto, J.A., Burlingame, A.L., Kao, A.W., Seeley, W.W., Argouarch, A.R., Vohra, M., Cuervo, A.M., Mohan, S.

[International Worm Meeting, 2017]

Progressive impairment of protein homeostasis is a universal hallmark of aging, stress and disease. One potential site for this cellular dysfunction is the lysosome, which is responsible for macromolecular breakdown and recycling. We previously showed in C. elegans that granulin peptides, the cleavage products of the neurodegenerative disease protein progranulin, selectively enhance TAR DNA-binding protein 43 (TDP-43) toxicity and impair its degradation (Salazar J. Neurosci 2015). Now, we provide genetic, biochemical, computational modeling and behavioral evidence supporting a role for C. elegans granulin 3 as a stress and age-responsive inhibitor of the lysosomal aspartyl protease, ASP-3/CTSD. C. elegans progranulin contains three granulins. We show that granulin production increases with age and stress. Transgenic expression of individual granulins impairs stress response and learning and memory. Granulins localize to the lysosome where they stimulate movement of the autophagy-promoting transcription factor HLH-30/TFEB from the cytosol to the nucleus. Co-immunoprecipitation experiments show that C. elegans granulin 3 interacts with the lysosomal aspartyl protease, ASP-3, which has previously been implicated in necrotic cell death. Protein docking models predict that granulin 3 binds to and occludes the protease active site. Supporting this, ASP-3 activity is significantly reduced in granulin expressing animals. Furthermore, the expression of granulin 3 in a deg-1(d) background delays the cell death of mechanosensory neurons and prolongs response to gentle touch. In addition, human patients carrying progranulin mutations produce more granulin fragments in degenerative brain regions than age-matched controls, and this is accompanied by a significant reduction in CTSD activity. Our results identify granulins as a novel class of endogenous peptide aspartyl protease inhibitor, which in analogy to serpins and cystatins we call aspartins. Given that age and stress can increase granulin production, we propose that the regulated production of granulin peptides can impair protein homeostasis and contribute to neurodegenerative disease pathogenesis. These results also suggest that dysregulation of lysosomal protease activity may more generally contribute to aging and age-related diseases.