Sulston JE (2003) Biosci Rep "C. elegans: the cell lineage and beyond."

Sulston JE

[Biosci Rep, 2003]

Thank you so very much for inviting me to be here. It gives me a mingled sense of humility at how much I owe to others, and of joy that the collective work on the worm has been recognized in this way.

Sulston JE (2003) Chembiochem "Caenorhabditis elegans: the cell lineage and beyond (Nobel lecture)."

Sulston JE

[Chembiochem, 2003]

Thank you so very much for inviting me to be here. It gives me a mingled sense of humility at how much I owe to others, and of joy that the collective work on the worm has been recognised in this way.

Ambros V (2001) Science "Development. Dicing up RNAs."

Ambros V

[Science, 2001]

RNA molecules are a constant source of joy to molecular biologists: They come in all shapes and sizes, and perform diverse informational, structural, and catalytic tricks in living cells. Perhaps less appreciated is their facility for regulating gene expression. Small regulatory RNAs figure prominently in two fascinating phenomena: gene inactivation by RNA interference (RNAi), and the control of gene expression during development.

Das, Alakananda et al. (2021) International Worm Meeting "Conserved extracellular proteins determine mechanoelectrical transduction channel localization and function in C. elegans touch receptor neurons"

Franco, Joy A., Pruitt, Beth L., Wang, Lingxin, Kuhl, Ellen, Wang, Lucy M., Das, Alakananda, Goodman, Miriam B., Chapman, Dail

[International Worm Meeting, 2021]

The sense of touch is made possible by neurons that use ion channels to convert mechanical stimuli into electrical signals. Many other proteins affect mechanosensation, either through direct force transfer by acting as physical tethers, or indirectly by modulating cell stiffness and morphology, protein trafficking, and channel positioning. Subcellular localization of mechanosensory ion channels is especially important for localized force sensation, since channels further away from the point of stimulation are recruited as stimulus intensity and speed increase. Here we examine the micro-environment of ion channels to investigate the molecular basis of channel positioning, leveraging the well-characterized MEC-4 mechanoelectrical transduction channel in C. elegans touch receptor neurons (TRNs). We show that MEC-4 channels localize to punctae distributed along TRN neurites in vivo but not in cultured TRNs in vitro, suggesting that in vivo channel localization depends on factors that are absent in vitro. Both time-lapse imaging and fluorescence recovery after photobleaching shows that most in vivo MEC-4 puncta are immobile over several minutes, suggesting that they are anchored to stable structures. To identify these structures, we screened mutants affecting plasma membrane proteins, cytoskeletal proteins, and extracellular matrix (ECM) proteins to investigate what factors regulate the positioning and stability of the MEC-4 puncta. In doing so, we discovered that the ECM protein nidogen regulates MEC-4 puncta distribution and both behavioral and electrical responses to touch. Nidogen associates with laminin networks in basement membranes and we show that both nidogen and laminin co-localize with MEC-4 puncta, in a manner that depends upon another ECM protein, MEC-1. To learn more about the physiological significance of channel puncta, we modeled mechanical strain distribution along a neurite in silico and found that physical attachment of the neurite to the ECM at puncta generates localized regions of increased strain. We speculate that this amplifies and focuses the mechanical stimulus for ion channel opening. Future experiments will determine whether these ECM proteins physically anchor the MEC-4 channels, accounting for the immobility of the MEC-4 puncta, and whether such a physical tether is responsible for ion channel opening in response to a mechanical stimulus.

Schlosser, A. et al. (2015) International Worm Meeting "Chronic exposure to pesticide residues exacerbates alpha-synuclein pathology in a Caenorhabditis elegans Parkinson's disease model."

Flaherty, D., Schlosser, A., Davis, M.

[International Worm Meeting, 2015]

Human health issues and disease have long been linked to environmental exposures which may be the greatest risk factors for the development of neurodegenerative diseases (Franco et al. 2010). Epidemiological studies show that exposure to environmental agents such as pesticides is a key contributor to the development and exacerbation of Parkinson's Disease (PD) (Franco et al. 2010). Intraneuronal inclusions, known as Lewy bodies, composed primarily of aggregated alpha-synuclein, are the primary causative formations associated with the loss of dopaminergic neurons and the development of PD (Baltazar et al. 2014; Brown et al. 2006). The loss of these neurons causes dysfunction of the basal ganglia and the subsequent inhibition of motor control, the defining characteristic of the disease (Baltazar et al. 2014). This study looks to assess the possible toxicological effects of chronic exposure to three common pesticides, chlorpyrifos, carbaryl and indoxacarb, at maximum tolerated residue levels set by the Environmental Protection Agency (EPA) in a Caenorhabditis elegans PD model. While the EPA employs strict regulations on individual pesticides, there are no regulations governing the mixing of pesticides. In this study, pesticides are tested both individually and as binary mixtures in order to investigate alpha-synuclein toxicity. Results from the study indicate that individually, these pesticides, with the exception of indoxacarb, have a noticeable effect on alpha-synuclein pathology. When combined to form binary mixtures, all pesticides have a drastic effect on alpha-synuclein pathology and mortality, despite being within EPA limits.

Otsuka AJ (1990) Worm Breeder's Gazette "ALTERATIONS IN UNC-44 ALLELES"

Otsuka AJ

[Worm Breeder's Gazette, 1990]

Preliminary analysis of six spontaneous unc-44 alleles indicates that alterations occur over a fairly large region in the genomic DNA. Southern analysis of two alleles from E. Hedgecock (rh1013 and rf1042) and four alleles (mn259, mn339, q331, and st200) from R. Herman and other labs (kindly provided by C. Kari, R. Herman, W. Li, and J. Shaw) indicated that restriction fragment differences from wild type are associated with all six alleles (see Franco et al., C. elegans Meeting abstracts, 1989). The construction of preliminary restriction maps of unc-44 cosmid (B0350 and C44A, kindly provided by A. Coulson and J. Sulston) and phage (DD#LRF1 and DD#LRF6) clones allows the approximate positioning of mutant changes. The absolute orientations of the cosmid and phage clones are based on positioning of these clones on the cosmid map. The overlapping of the cosmid and phage clones has not yet been demonstrated. Unfortunately, the cosmid isolate that could quickly clarify the situation (C02C3) deleted during growth. [See Figure 1]

Liu H et al. (2013) J Ethnopharmacol "Lifespan extension by n-butanol extract from seed of Platycladus orientalis in Caenorhabditis elegans."

Liu H, Liang F, Su W, Zhang Y, Li P, Xie X, Lv M, Pei Z, Wang Y, Wang N

[J Ethnopharmacol, 2013]

AIM OF THE STUDY: As a traditional Chinese medicine, seed of Platycladus orientalis(Linnaeus) Franco has been extensively used as a tonic and sedative remedy. The present study was conducted to investigate whether lifespan was extended and the mechanisms of n-butanol extract from seed of Platycladus orientalis (BSPO) in Caenorhabditis elegans. The findings could provide the pharmacological basis for a treatment in traditional medicine. MATERIALS AND METHODS: Lifespan extension by BSPO was evaluated under normal culture conditions and in a stress test. A possible mechanism of the anti-aging effect of BSPO, a change in the stress-resistance of related proteins, was also investigated in C. elegans. RESULTS: It has been shown that BSPO could significantly extend lifespan of C. elegans in a concentration dependent manner under normal culture conditions and stress. Further studies demonstrated that BSPO treatment significantly decreased reactive oxygen species (ROS) accumulation, up-regulated resistance to stress of related proteins, including glutathione S-transferase-4 (GST-4) and heat shock protein-16.2 (HSP-16.2), and reduced the amount of lipofuscin in transgenic C. elegans. CONCLUSION: These results indicated that BSPO extended the lifespan, which could be attributed to its direct ROS scavenging activity, reducing the amount of lipofuscin and increasing the expression of gens associated with resistance to stress. These obtained data provided valuable support for traditional clinical practice to extend lifespan and to provide tonic remedy.

Collin Ewald et al. (2006) European Worm Meeting "Characterization of the Worm Homolog of memo, a Gene that Acts Downstream of the Mammalian EGF Pathway"

Nancy Hynes, Collin Ewald, Joy Alcedo

[European Worm Meeting, 2006]

Collin Ewald, Nancy Hynes and Joy Alcedo. The ErbB2 receptor tyrosine kinase has been shown to play an important role in cancer metastases. This receptor is often overexpressed in human tumors of diverse origins, which include mammary and ovarian tissues. Two of the five major autophosphorylated tyrosine residues of the cytoplasmic tail of ErbB2--Tyr1201 and Tyr1227--are sufficient to restore the migratory phenotype of breast carcinoma cells, whereas the receptor lacking all of the 5 major autophosphorylation sites is impaired in stimulating cell migration. A novel protein called MEMO (Mediator of ErbB2-driven cell motility) has been identified and found to interact with the phosphorylated Tyr1227 residue (1). MEMO controls cell migration by relaying extracellular signals to the microtubule cytoskeleton (1). Interestingly, memo is highly conserved through evolution and its homolog in C. elegans has a sequence identity of 53%. The aim of this study is to investigate the role of memo in C. elegans. It is possible that memo is involved in cell migration and/or in the signal integration of the worm EGF pathway.. (1) R. Marone et al. (2004) Memo mediates ErbB2-driven cell motility. Nature Cell Biol 6: 515 - 522.

Astrid Kleinert et al. (2006) European Worm Meeting "Analysis of Insulin-Like Peptides in C. elegans by Mass Spectrometry"

Astrid Kleinert, Daniel Hess, Joy Alcedo, Jan Hofsteenge

[European Worm Meeting, 2006]

Astrid Kleinert, Daniel Hess, Jan Hofsteenge and Joy Alcedo. Genetic analyses in C. elegans have implicated an endocrine signaling pathway, the insulin/IGF-1 pathway, in regulating lifespan. Mutations in the gene daf-2, which encodes an insulin/IGF-1 receptor homologue, can increase worm lifespan by more than 100% (1). In addition, the insulin and IGF-1 pathways have been shown to influence fly and mouse lifespan (2-5).. Although downstream components of the DAF-2 pathway have been studied in detail, far less is known about the putative DAF-2 ligands predicted to be encoded by 38 insulin-like genes in the worm. It remains unknown which of the predicted insulin-like peptides are present in wild type or in longevity mutants. In order to determine this, we have initiated a project to analyze the polypeptide subfractions of the C. elegans proteome by mass spectrometry. Worm lysates will be prepared from mixed stage, wild-type worms, excluding membrane-bound proteins. Acid-ethanol extraction and gel filtration will be tested as methods to obtain a subfraction enriched in small polypeptides. Peptide identification will be done by liquid chromatography and tandem mass spectrometry (LC-MS/MS). Data analyses will be carried out using a MASCOT search database, which contains a subset of the UNIPROT database and a database generated of relevant C. elegans polypeptides. Finally, using the SILAC method for quantification (6), we plan to compare differences in the levels of polypeptides, e.g., insulin-like peptides, between wild-type worms and longevity mutants. . References: (1) Kenyon et al., 1993. Nature 366: 461-4. (2) Clancy et al., 2001. Science 292: 104-6. (3) Tatar et al., 2001. Science 292: 107-110. (4) Holzenberger et al., 2003. Nature 421: 182-7. (5) Blher et al., 2003. Science 299:572-4. (6) Krijgsveld et al., 2003. Nature Biotech. 21: 927-931.

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).