Mariani, A. et al. (2017) International Worm Meeting "Characterization of lncRNA C30E1.9 in C. elegans."

Link, C., Mariani, A.

[International Worm Meeting, 2017]

Nuclear Enriched Abundant Transcript 1 (NEAT1) is a long non-coding RNA necessary for the formation of nuclear bodies called paraspeckles (composed of about 40 proteins) in mammals. NEAT1 is expressed as two isoforms (3.7kb and 23kb). This transcript has been implicated in different neurodegenerative diseases (including ALS/FTD and MS), brain viral infection (Japanese encephalitis virus and rabies virus), in addition to playing an oncogenic role in most solid tumors. In regards to ALS, it has been shown that NEAT1 is directly bound by TDP-43 and that its expression is highly up-regulated in human motor neurons presenting ALS pathology. In our transcriptome analysis of TDP-1 knock-out and FUS knock-out C. elegans we noticed a significant overexpression of a transcript (C30E1.9), which presents itself in two isoforms of length ~4kb and 23kb. We hypothesized that this transcript was the NEAT1 ortholog in nematodes. We performed smRNA FISH experiments and observed the formation of nuclear bodies in both N2 and TDP-1 knock-out worms: no statistical significance was noticed in the number of nuclear bodies between the two strains. As is the case for NEAT1 in mammals, we did not observe this transcript in the germline. We performed smRNA FISH in strains expressing human TDP-43::GFP and TDP-1::GFP in order to determine whether the lncRNA C30E1.9 co-localizes with TDP-43 and TDP-1: no strong co-localization was found. Feeding RNAi against the C30E1.9 transcript has so far been inconclusive, as no phenotypes have been observed, but clear reduction in the C30E1.9 nuclear bodies has not been observed. Ultimately, given that NONO protein in mammals is required for NEAT1 driven paraspeckle nucleation, we performed smRNA FISH in a NONO-1 (C. elegans ortholog of human NONO) knock-out balancer strain: we found no evidence of reduced number of nuclear bodies between NONO-1 knock-out and NONO-1 expressing strains. We conclude that C30E1.9 is most likely not a NEAT1 ortholog, but it could potentially play an important regulatory function in C. elegans given its expression pattern, the formation of nuclear bodies, and its greatly elevated expression levels in C. elegans ALS disease model.

Mariani, Luca et al. (2013) International Worm Meeting "Role of the histone demethylase RBR-2 in neuronal development."

Salcini, Anna Elisabetta, Vandamme, Julien, Mariani, Luca

[International Worm Meeting, 2013]

Background. Methylation of lysine residues (K) located on histone proteins is believed to be an important regulator of chromatin structure. This modification is associated both to gene expression and repression, depending on the residue modified, and is regulated by two classes of enzymes: Lysine Methyl Transferases (KMTs) and Lysine Demethylases (KDMs). In the last few years, aberrant histone lysine methylation has been associated to neurological and psychiatric disorders, suggesting that such epigenetic mechanisms might play a central role in brain development and functions. Results. We performed a screen using available mutant alleles for selected KDMs, searching for defective axon migration and neuronal cell fates. Among others, we identified RBR-2, a Jumonji domain-containing protein with demethylase activity on tri-methylated lysine 4 of histone 3 (H3K4me3), as a potential factor involved in some aspects of neuronal functions. Analyses of transgenic animals and immunofluorescence with specific antibodies show that RBR-2 protein is expressed in several cell types, including neurons, at embryonic and larval stages, and, accordingly with its function, it localizes in the nucleus. Mutant animals show aberrant axon migration of some neurons that pioneer the ventral nerve cord. These defects arise during embryonic development and can be rescued by re-expressing the wild-type but not the catalytically inactive variant of RBR-2, indicating that its enzymatic activity is essential for the correct guidance of the neurons. Currently, we are measuring genetic interactions with other genes implicated in the process of axon guidance in order to identify in which pathway RBR-2 is acting. Conclusions and Perspectives. These data provide evidences that RBR-2 plays an important role in some aspects of the development of the nervous system in C. elegans. Being RBR-2 a demethylase for H3K4me3, an activating mark, thus acting as a transcriptional repressor, future analyses will be directed at identifying target genes directly or indirectly regulated by RBR-2. To this purpose, experiments such as ChIP and RNA extraction followed by deep sequencing, both in wild-type and mutated lines, are planned.

Mariani L et al. (2016) Development "The H3K4me3/2 histone demethylase RBR-2 controls axon guidance by repressing the actin-remodeling gene wsp-1."

Salcini AE, Riveiro A, Lussi YC, Vandamme J, Mariani L

[Development, 2016]

The dynamic regulation of histone modifications is important for modulating transcriptional programs during development. Aberrant H3K4 methylation is associated with neurological disorders, but how the levels and the recognition of this modification affect specific neuronal processes is unclear. Here, we show that RBR-2, the sole homolog of the KDM5 family of H3K4me3/2 demethylases in Caenorhabditis elegans, ensures correct axon guidance by controlling the expression of the actin regulator wsp-1. Loss of rbr-2 results in increased levels of H3K4me3 at the transcriptional start site of wsp-1, with concomitant higher wsp-1 expression responsible for defective axon guidance. In agreement, overexpression of WSP-1 mimics rbr-2 loss, and its depletion restores normal axon guidance in rbr-2 mutants. NURF-1, an H3K4me3-binding protein and member of the chromatin-remodeling complex NURF, is required for promoting aberrant wsp-1 transcription in rbr-2 mutants and its ablation restores wild-type expression of wsp-1 and axon guidance. Thus, our results establish a precise role for epigenetic regulation in neuronal development by demonstrating a functional link between RBR-2 activity, H3K4me3 levels, the NURF complex and the expression of WSP-1.

Pollard AK et al. (2020) Astrobiology "Molecular Muscle Experiment: Hardware and Operational Lessons for Future Astrobiology Space Experiments."

Mariani A, Ellwood RA, Etheridge T, Pollard AK, Deane CS, Mierzwa BE, Cooke M, Balsamo M, Szewczyk NJ, Hewitt JE, Vanapalli SA, Gaffney CJ

[Astrobiology, 2020]

Biology experiments in space seek to increase our understanding of what happens to life beyond Earth and how we can safely send life beyond Earth. Spaceflight is associated with many (mal)adaptations in physiology, including decline in musculoskeletal, cardiovascular, vestibular, and immune systems. Biological experiments in space are inherently challenging to implement. Development of hardware and validation of experimental conditions are critical to ensure the collection of high-quality data. The model organism <b> <i>Caenorhabditis elegans</i> </b> has been studied in space for more than 20 years to better understand spaceflight-induced (patho)physiology, particularly spaceflight-induced muscle decline. These experiments have used a variety of hardware configurations. Despite this, hardware used in the past was not available for our most recent experiment, the Molecular Muscle Experiment (MME). Therefore, we had to design and validate flight hardware for MME. MME provides a contemporary example of many of the challenges faced by researchers conducting <b> <i>C. elegans</i> </b> experiments onboard the International Space Station. Here, we describe the hardware selection and validation, in addition to the ground-based experiment scientific validation testing. These experiences and operational solutions allow others to replicate and/or improve our experimental design on future missions.

Quartey MO et al. (2021) Sci Rep "The A(1-38) peptide is a negative regulator of the A(1-42) peptide implicated in Alzheimer disease progression."

Pennington PR, Heistad RM, Nyarko JNK, Barnes JR, Bolanos MAC, Parsons MP, Knudsen KJ, De Carvalho CE, Leary SC, Mousseau DD, Buttigieg J, Maley JM, Quartey MO

[Sci Rep, 2021]

The pool of -Amyloid (A) length variants detected in preclinical and clinical Alzheimer disease (AD) samples suggests a diversity of roles for A peptides. We examined how a naturally occurring variant, e.g. A(1-38), interacts with the AD-related variant, A(1-42), and the predominant physiological variant, A(1-40). Atomic force microscopy, Thioflavin T fluorescence, circular dichroism, dynamic light scattering, and surface plasmon resonance reveal that A(1-38) interacts differently with A(1-40) and A(1-42) and, in general, A(1-38) interferes with the conversion of A(1-42) to a -sheet-rich aggregate. Functionally, A(1-38) reverses the negative impact of A(1-42) on long-term potentiation in acute hippocampal slices and on membrane conductance in primary neurons, and mitigates an A(1-42) phenotype in Caenorhabditis elegans. A(1-38) also reverses any loss of MTT conversion induced by A(1-40) and A(1-42) in HT-22 hippocampal neurons and APOE 4-positive human fibroblasts, although the combination of A(1-38) and A(1-42) inhibits MTT conversion in APOE 4-negative fibroblasts. A greater ratio of soluble A(1-42)/A(1-38) [and A(1-42)/A(1-40)] in autopsied brain extracts correlates with an earlier age-at-death in males (but not females) with a diagnosis of AD. These results suggest that A(1-38) is capable of physically counteracting, potentially in a sex-dependent manner, the neuropathological effects of the AD-relevant A(1-42).

Danielle Thierry-Mieg et al. (2003) Worm Breeder's Gazette "www.wormgenes.org , a new gene centered database"

Vahan Simonyan, Michel Potdevin, Mark Sienkiewicz, Yuji KOHARA, Jean Thierry-Mieg, Danielle Thierry-Mieg, Tadasu SHIN-I

[Worm Breeder's Gazette, 2003]

Wormgenes is a new resource for C.elegans offering a detailed summary about each gene and a powerful query system.

Tangrodchanapong T et al. (2020) Front Pharmacol "Frondoside A Attenuates Amyloid- Proteotoxicity in Transgenic Caenorhabditis elegans by Suppressing Its Formation."

Tangrodchanapong T, Sobhon P, Meemon K

[Front Pharmacol, 2020]

Oligomeric assembly of Amyloid- (A) is the main toxic species that contribute to early cognitive impairment in Alzheimer's patients. Therefore, drugs that reduce the formation of A oligomers could halt the disease progression. In this study, by using transgenic <i>Caenorhabditis elegans</i> model of Alzheimer's disease, we investigated the effects of frondoside A, a well-known sea cucumber <i>Cucumaria frondosa</i> saponin with anti-cancer activity, on A aggregation and proteotoxicity. The results showed that frondoside A at a low concentration of 1 M significantly delayed the worm paralysis caused by A aggregation as compared with control group. In addition, the number of A plaque deposits in transgenic worm tissues was significantly decreased. Frondoside A was more effective in these activities than ginsenoside-Rg3, a comparable ginseng saponin. Immunoblot analysis revealed that the level of small oligomers as well as various high molecular weights of A species in the transgenic <i>C. elegans</i> were significantly reduced upon treatment with frondoside A, whereas the level of A monomers was not altered. This suggested that frondoside A may primarily reduce the level of small oligomeric forms, the most toxic species of A. Frondoside A also protected the worms from oxidative stress and rescued chemotaxis dysfunction in a transgenic strain whose neurons express A. Taken together, these data suggested that low dose of frondoside A could protect against A-induced toxicity by primarily suppressing the formation of A oligomers. Thus, the molecular mechanism of how frondoside A exerts its anti-A aggregation should be studied and elucidated in the future.

Hodgkin JA (1998) International Journal of Developmental Biology "Seven types of pleiotropy."

Hodgkin JA

[International Journal of Developmental Biology, 1998]

Pleiotropy , a situation in which a single gene influences multiple phenotypic tra its, can arise in a variety of ways. This paper discusses possible underlying mechanisms and proposes a classification of the various phenomena involved.

Tuck S (2011) Curr Biol "Extracellular vesicles: budding regulated by a phosphatidylethanolamine translocase."

Tuck S

[Curr Biol, 2011]

Recent work on a Caenorhabditis elegans transmembrane ATPase reveals a central role for the aminophospholipid phosphatidylethanolamine in the production of a class of extracellular vesicles.

Viney ME et al. (2004) Naturwissenschaften "Is dauer pheromone of Caenorhabditis elegans really a pheromone?"

Viney ME, Franks NR

[Naturwissenschaften, 2004]

Animals respond to signals and cues in their environment. The difference between a signal (e.g. a pheromone) and a cue (e.g. a waste product) is that the information content of a signal is subject to natural selection, whereas that of a cue is not. The model free-living nematode Caenorhabditis elegans forms an alternative developmental morph (the dauer larva) in response to a so-called 'dauer pheromone', produced by all worms. We suggest that the production of 'dauer pheromone' has no fitness advantage for an individual worm and therefore we propose that 'dauer pheromone' is not a signal, but a cue. Thus, it should not be called a pheromone.