Gao W et al. (2020) Small "Nitrogen-Doped Carbonized Polymer Dots: A Potent Scavenger and Detector Targeting Alzheimer's -Amyloid Plaques."

Dong X, Wang W, Gao W, Sun Y

[Small, 2020]

The fibrillization and deposition of -amyloid protein (A) are recognized to be the pathological hallmarks of Alzheimer's disease (AD), which signify the need for the effective detection and inhibition of A accumulation. Development of multifunctional agents that can inhibit A aggregation, rapidly disaggregate fibrils, and image aggregates is one of the effective strategies to treat and diagnose AD. Herein, the multifunctionality of nitrogen-doped carbonized polymer dots (CPDs) targeting A aggregation is reported. CPDs inhibit the fibrillization of A monomers and rapidly disintegrate A fibrils by electrostatic interactions, hydrogen-bonding and hydrophobic interactions with A in a time scale of seconds to minutes. Moreover, the interactions make CPDs label A fibrils and emit enhanced red fluorescence by the binding, so CPDs can be used for in vivo imaging of the amyloids in transgenic Caenorhabditis elegans CL2006 as an AD model. Importantly, CPDs are demonstrated to scavenge the in vivo amyloid plaques and to promote the lifespan extension of CL2006 strain by alleviating the A-triggered toxicity. Taken together, the multifunctional CPDs show an exciting prospect for further investigations in A-targeted AD treatment and diagnosis, and this study provides new insight into the development of carbon materials in AD theranostics.

Olson, Andrew et al. (2017) International Worm Meeting "The Role of Post-Translational Modifications in the Regulation of Serotonin Signaling."

Olson, Andrew, Koelle, Michael, Kumar, Santosh

[International Worm Meeting, 2017]

C. elegans uses serotonin as a neurotransmitter to slow locomotion, and we have used this model system to discover that post-translational modifications appear to regulate serotonin signaling. Through large-scale genetic screens for mutants that fail to paralyze in response to exogenous serotonin, we found that C. elegans mutants for either of two subunits of the ELPC Elongator Protein Complex are defective for serotonin signaling. Conversely, transgenic animals overexpressing ELPC are hypersensitive to the effects of exogenous serotonin. ELPC is conserved from C. elegans to humans and functions as a cytoplasmic lysine acetylase to reversibly modify other proteins. This is the first time that ELPC or lysine acetylation has been implicated in regulating serotonin signaling. We used two-dimensional gel electrophoresis to show that in C. elegans lysates, Gao, a neural G protein encoded by the goa-1 gene through which serotonin signals to slow locomotion, exists as a complex series of species of differing charge. Acetylation eliminates the positive charge on a lysine side chain, and differential acetylation on several Lys could produce the complex pattern of Gao species we see. Our preliminary results suggest that the series of differentially charged Gao species in wild-type lysates shifts to a less complex and more positively charged set of Gao species in lysates of ELPC mutants, as would be predicted if Gao is acetylated by ELPC. We isolated Gao from both mouse brain and C. elegans lysates and analyzed the purified proteins for post-translational modifications using mass spectrometry. In both species, Gao is acetylated on several conserved Lys residues near the N-terminus. We note that the signaling defects in ELPC mutants are much more restricted than those of Gao null mutants. Both ELPC and Gao mutants are defective for response to exogenous serotonin, but Gao null mutants have additional defects not seen in ELPC mutants, including defects in response to exogenous dopamine as well as in many behavioral assays. Thus we hypothesize that ELPC may reversibly acetylate Gao to specifically regulate its ability to be activated by serotonin receptors, while not strongly affecting its ability mediate signaling by other receptors. We are using CRISPR-Cas9 technology to mutate the acetylated Lys residues of Gao to the similar but non-acetylatable amino acid arginine to determine if acetylation at specific positions is responsible for regulating serotonin signaling.

Hofler, Catherine et al. (2011) International Worm Meeting "AGS-3 alters C. elegans behavior after food deprivation via RIC-8 activation of the neural G protein Gao."

Hofler, Catherine, Koelle, Michael

[International Worm Meeting, 2011]

Like all animals, C. elegans modifies a number of behaviors upon food deprivation in order to seek food. These behavioral changes depend on neurotransmitters and peptides that typically signal through the major neural G protein Gao, suggesting that signaling through this G protein ultimately mediates responses to food deprivation. Proteins containing the G Protein Regulator (GPR) domain bind to Gao in vitro, but the biological functions of GPR proteins in neurons and the mechanism by which they might affect G protein signaling has remained unclear. We found that the conserved GPR domain protein AGS-3 activates Gao signaling in vivo to allow C. elegans to alter several behaviors after food deprivation. These behaviors include octanol avoidance, area-restricted search, and egg laying. AGS-3 protein in whole worm lysates undergoes a progressive change in its biochemical fractionation pattern upon food deprivation, demonstrating that food deprivation changes the physical state of the protein. Cell-specific rescue and cell-specific inactivation experiments show that AGS-3 and Gao act together in the ASH chemosensory neurons to allow food deprivation to modify response to octanol. Genetic epistasis experiments show that AGS-3 activation of Gao in the ASHs requires the guanine nucleotide exchange factor RIC-8. Conversely, RIC-8 function in the ASHs also requires AGS-3. Using purified recombinant proteins, we characterized interactions of the proteins consistent with the genetic epistasis results. AGS-3 forms a complex with the the inactive, GDP-bound form of Gao, and RIC-8 can act on this complex to promote nucleotide exchange and dissociation of all the proteins, generating active Gao-GTP. These results identify a biological role for AGS-3 in response to food deprivation and indicate the mechanism for its activation of Gao signaling in vivo.

Heather A Hess et al. (2004) East Coast Worm Meeting "RGS-7 Completes a Receptor-independent Heterotrimeric G Protein Signaling Cycle to Regulate Mitotic Spindle Positioning in C. elegans"

Michael R Koelle, Heather A Hess

[East Coast Worm Meeting, 2004]

Heterotrimeric G proteins promote astral microtubule forces on centrosomes to position mitotic spindles properly during asymmetric cell division in C. elegans embryos. While all previously studied G protein functions require activation by seven-transmembrane receptors, this function appears to be receptor-independent, and the active form of the G proteins remains unclear. We obtained mutants for all 13 C. elegans regulators of G protein signaling and found that one, RGS-7, decreases the speed and magnitude of centrosome movements. The effects of RGS-7 require two redundant Gao-related G proteins and their non-receptor activators. Using recombinant proteins, we found that the non-receptor activator RIC-8 stimulates GTP binding by Gao, and the RGS domain of RGS-7 stimulates GTP hydrolysis by Gao. These results demonstrate that the active species in the receptor-independent G protein cycle is GaoGTP, and that RGS-7 completes the cycle by driving Gao to its inactive, GDP-bound form.

K Omata et al. (1999) International C. elegans Meeting "Characterization of the neural circuit of C. elegans: model analysis of the touch response"

F Yonezawa, K Omata, K Kawamura

[International C. elegans Meeting, 1999]

In order to characterize the neural circuit of C. elagans, we construct a simple model by making use of the data table completed recently by Oshio et al . [1]. We assume that the signal of a neuron is calculated by the product of the signals from the neighboring neurons, and we investigate the touch sensitivity to continuous stimuli described by sinusoidal functions as defined in the rage from 0.0 to 1.0. We calculate the responses of the motor neurons by changing the frequencies of the stimuli. In our calculations, we change only the frequency w PLM for the input signal to the sensory neuron PLM, while the frequency for the other sensory neurons ALM, AVM and PVM is fixed to be a same value w 0 . We show that the output signals from the motor neurons A and B oscillate in time. We measure the minima of the oscillation for each w PLM value. The plot of the minima versus w PLM shows different hehaviors for the case of the neuron A and B. As for the signals from the neuron A, the values of the minima are widely distributed between 0.0 and 1.0 for all w PLM . As for the signals from the neuron B, on the other hand, the features are different for different w PLM values. (a) In the high frequency region of w PLM / w 0 0.4, the oscillation is simple harmonic and there exists only one minimum value (I min = 0.0). (b) As w PLM / w 0 is decreased, another minimum appears at a certain frequency, and the bifurcation takes place discontinuously. This behavior is different from usual continuous bifurcation observed in nonlinear systems. After a few discontinuous branching occur, signals with five periods can be seen in the intermediate frequency region of 0.3 w PLM / w 0 w PLM / w 0 [1] K. Oshio et al. ; C. elegans synaptic connectivity data'', Technical Report, CCEP, Keio Future No.1 (1998).

Wang C et al. (2018) Nat Commun "Author Correction: Small-molecule TFEB pathway agonists that ameliorate metabolic syndrome in mice and extend C. elegans lifespan."

Zhao T, Oswald NW, Li Y, Lin R, Wang C, Jaramillo J, Zhou A, McMillan EA, Douglas PM, MacMillan JB, Huang G, Luo M, Gao J, Mendiratta S, Lin Z, Wang Z, Niederstrasser H, Posner BA, Brekken RA, White MA

[Nat Commun, 2018]

The originally published version of this Article contained an error in the spelling of the author Nathaniel W. Oswald, which was incorrectly given as Nathaniel W. Olswald. This has now been corrected inboth the PDF and HTML versions of the Article.

Nawa Y et al. (1985) Parasite Immunol "Defective protective capacity of W/Wv mice against Strongyloides ratti infection and its reconstitution with bone marrow cells."

Kotani M, Nawa Y, Kiyota M, Korenaga M

[Parasite Immunol, 1985]

The susceptibility of congenitally anemic, and mast cell deficient W/Wv mice to infection with Strongyloides ratti was examined. After a primary infection, W/Wv mice showed greater and more persistent peak larval counts than did normal littermates. Worm expulsion was also slower in W/Wv mice than in +/+ mice. Furthermore, difference in susceptibility was expressed as early as 24 h after infection, suggesting not only that protective mechanisms of the gut but also of the connective tissue were defective in W/Wv mice. Reconstitution with bone marrow or spleen cells from +/+ mice was effective in restoring the protective response in W/Wv mice, whereas thymocytes or mesenteric lymph nodes had no effect. Both connective tissue and mucosal mast cells were repaired in W/Wv mice after marrow reconstitution and infection. Since relatively long incubation period was required for the expression of such reconstituting activities, bone marrow cells seem to contain precursor cells of the effector and/or regulator cells.

Henderson ST et al. (1994) Worm Breeder's Gazette "The lag-2 Gene Encodes a Protein With Homology to Drosophila Delta and is Expressed in the Distal Tip Cell"

Gao DL, Henderson ST, Lambie EJ, Kimble JE

[Worm Breeder's Gazette, 1994]

The lag-2 gene encodes a protein with homology to Drosophila Delta and is expressed in the distal tip cell. Sam Henderson, Dali Gao, Eric Lambie#, and Judith Kimble, University of Wisconsin, Madison WI 53706, Dartmouth College, Hanover, NH 03755

Casiraghi M et al. (2004) Int J Parasitol "Mapping the presence of Wolbachia pipientis on the phylogeny of filarial nematodes: evidence for symbiont loss during evolution."

Guerrero R, Bandi C, Franceschi A, Pocacqua V, Gardner SL, Casiraghi M, Martin C, Bain O

[Int J Parasitol, 2004]

Wolbachia pipientis is a bacterial endosymbiont associated with arthropods and filarial nematodes. In filarial nematodes, W. pipientis has been shown to play an important role in the biology of the host and in the immuno-pathology of filariasis. Several species of filariae, including the most important parasites of humans and animals (e.g. Onchocerca volvulus, Wuchereria bancrofti and Dirofilaria immitis) have been shown to harbour these bacteria. Other filarial species, including an important rodent species (Acanthocheilonema viteae), which has been used as a model for the study of filariasis, do not appear to harbour these symbionts. There are still several open questions about the distribution of W. pipientis in filarial nematodes. Firstly the number of species examined is still limited. Secondly, it is not clear whether the absence of W. pipientis in negative species could represent an ancestral characteristic or the result of a secondary loss. Thirdly, several aspects of the phylogeny of filarial nematodes are still unclear and it is thus difficult to overlay the presence/absence of W. pipientis on a tree representing filarial evolution. Here we present the results of a PCR screening for W. pipientis in 16 species of filariae and related nematodes, representing different families/subfamilies. Evidence for the presence of W. pipientis is reported for five species examined for the first time (representing the genera Litomosoides, Litomosa and Dipetalonema); original results on the absence of this bacterium are reported for nine species; for the remaining two species, we have confirmed the absence of W. pipientis recently reported by other authors. In the positive species, the infecting W. pipientis bacteria have been identified through 16S rDNA gene sequence analysis. In addition to the screening for W. pipientis in 16 species, we have generated phylogenetic reconstructions based on mitochondrial gene sequences (12S rDNA; COI), including a total of 28 filarial species and related spirurid nematodes. The mapping of the presence/absence of W. pipientis on the trees generated indicates that these bacteria have possibly been lost during evolution along some lineages of filarial nematodes.

Olson, Andrew C et al. (2013) International Worm Meeting "The Role of Post-Translational Modifications in the Regulation of Serotonin Signalling."

Olson, Andrew C, Koelle, Michael R

[International Worm Meeting, 2013]

C. elegans uses serotonin as a neurotransmitter to slow locomotion, and we have used this model system to discover that post-translational modifications seem to regulate serotonin signaling. First, through large-scale genetic screens for mutants that fail to respond properly to serotonin (Gurel et al., 2012), we found that C. elegans strains carrying mutations in either of two subunits of the ELPC ELongator" Protein Complex are defective for response to serotonin. ELPC is highly conserved from C. elegans to humans and functions as a lysine acetylase to reversibly modify other proteins. This is first time that ELPC or lysine acetylation has been implicated in regulating serotonin signaling. Second, our lab has also shown that Gao, a G protein through which serotonin signals to slow locomotion, is post-translationally modified in a manner that alters its charge, which is a hallmark of lysine acetylation. We hypothesize that ELPC may reversibly acetylate Gao (and/or one of the other proteins that mediate serotonin signaling) to regulate serotonin response. Serotonin regulates worm movement in C. elegans by redundantly signaling through the MOD-1 serotonin-gated ion channel and the SER-4 G Protein Coupled serotonin Receptor (GPCR), the GPCR through which Gao signals (Gurel et al. 2012). It is likely that ELPC modifies signaling through one or both of these receptors. To test this genetically, we have developed an assay that optogenetically stimulates the release of serotonin from the NSM and ADF serotonergic neurons. This strongly decreases the speed of worms that have intact MOD-1 and SER-4 signaling pathways, but this serotonin response is defective in animals missing one or both of the receptors. With WormLab worm-tracking software we are able to monitor the speed of worms throughout the course of the experiment. Using this assay we will be able to genetically determine if ELPC affects signaling through the MOD-1 or SER-4 receptor. We are also working to identify the post-translational modifications of Gao using mass spectrometry. Analysis of Gao immunoprecipitated from both C. elegans lysates as well as mouse brain lysates will allow us to determine if worm and mammalian Gao are equivalently modified.