Wong, Wan-Rong et al. (2021) MicroPubl Biol

Oh, Jun Young, Wong, Wan-Rong, Maher, Shayda, Sternberg, Paul W, Gharib, Shahla, Brugman, Katherine I

[MicroPubl Biol, 2021]

Retinoic acid (RA), the active metabolite of vitamin A, broadly regulates gene expression. The RA signaling pathway plays an essential role in embryonic development, including the development of the body axis, eye, brain, and heart (Ghyselinck & Duester, 2019). One of the key enzymes in the biosynthesis of RA is aldehyde dehydrogenase 1 family member A3 (ALDH1A3). ALDH1A3 converts retinaldehyde to retinoic acid and it is expressed early in forebrain development (McCaffery & Drager, 1994). Several mutations in ALDH1A3 have been implicated in patients with autosomal recessive microphthalmia and other neurological disorders (Fares-Taie et al., 2013; Roos et al., 2014). However, current animal models of ALDH1A3 have large truncations of the protein. Direct evidence of the effects of missense variants on ALDH1A3 protein activity has not yet been obtained.

Wan G et al. (2018) Nature "Spatiotemporal regulation of liquid-like condensates in epigenetic inheritance."

Shukla A, Wan G, Kennedy S, Phillips CM, Fields BD, Spracklin G

[Nature, 2018]

Non-membrane-bound organelles such as nucleoli, processing bodies, Cajal bodies and germ granules form by the spontaneous self-assembly of specific proteins and RNAs. How these biomolecular condensates form and interact is poorly understood. Here we identify two proteins, ZNFX-1 and WAGO-4, that localize to Caenorhabditis elegans germ granules (P granules) in early germline blastomeres. Later in germline development, ZNFX-1 and WAGO-4 separate from P granules to define an independent liquid-like condensate that we term the Z granule. In adult germ cells, Z granules assemble into ordered tri-condensate assemblages with P granules and Mutator foci, which we term PZM granules. Finally, we show that one biological function of ZNFX-1 and WAGO-4 is to interact with silencing RNAs in the C. elegans germline to direct transgenerational epigenetic inheritance. We speculate that the temporal and spatial ordering of liquid droplet organelles may help cells to organize and coordinate the complex RNA processing pathways that underlie gene-regulatory systems, such as RNA-directed transgenerational epigenetic inheritance.

Wan F et al. (2014) Biogerontology "Lifespan extension in Caenorhabiditis elegans by several traditional Chinese medicine formulas."

Li M, Ju W, Xian J, Wan F, Li H, Liu D, Zhi D, AbuLizi A

[Biogerontology, 2014]

There is considerable interest in using traditional Chinese medicine formulas (TCMF) to delay aging or treat age-related diseases. Due to cost and duration, the beneficial effects of TCMF on prolongation are mainly extrapolated from vitro studies or physiological indexes. Little is known about whether TCMF are beneficial in whole level, particularly with respect to lifespan. To address this issue, we selected eight formulas with anti-oxidative activity and examined their effects on the lifespan of Caenorhabditis elegans. The results showed that seven of the eight formulas could prolong lifespan of TK22 mutant significantly and five of the eight formulas could obviously extend lifespan of N2 wild-type. To further characterize the prolongation effects, oxidative stress, thermal stress and reproduction test were assayed. We found that the formulas that extended lifespan of TK22 could also protect it from oxidative stress, without reducing the reproductive capacity. Meanwhile, the formulas that prolonged lifespan of N2 wild-type could also enhance its resistance against thermal stress, with damaging the reproductive fitness. These observations indicate that TCMF used in our experiment could be potential therapeutics for anti-aging.

Wan QL et al. (2017) Aging (Albany NY) "Metabolomic signature associated with reproduction-regulated aging in Caenorhabditis elegans."

Wu GS, Li Z, Wan QL, Ding AJ, Pu YZ, Luo HR, Liu J, Shi X

[Aging (Albany NY), 2017]

In Caenorhabditis elegans (C. elegans), ablation of germline stem cells (GSCs) leads to infertility, which extends lifespan. It has been reported that aging and reproduction are both inextricably associated with metabolism. However, few studies have investigated the roles of polar small molecules metabolism in regulating longevity by reproduction. In this work, we combined the nuclear magnetic resonance (NMR) and ultra-performance liquid chromatography-mass spectrometry (UPLC-MS) to profile the water-soluble metabolome in C. elegans. Comparing the metabolic fingerprint between two physiological ages among different mutants, our results demonstrate that aging is characterized by metabolome remodeling and metabolic decline. In addition, by analyzing the metabolic profiles of long-lived germline-less glp-1 mutants, we discovered that glp-1 mutants regulate the levels of many age-variant metabolites to attenuate aging, including elevated concentrations of the pyrimidine and purine metabolism intermediates and decreased concentrations of the citric acid cycle intermediates. Interestingly, by analyzing the metabolome of daf-16;glp-1 double mutants, our results revealed that some metabolic exchange contributing to germline-mediated longevity was mediated by transcription factor FOXO/DAF-16, including pyrimidine metabolism and the TCA cycle. Based on a comprehensive metabolic analysis, we provide novel insight into the relationship between longevity and metabolism regulated by germline signals in C. elegans.

Wan X et al. (2024) J Vis Exp "Volatile Sex Pheromone Extraction and Chemoattraction Assay in Caenorhabditis elegans."

Wan X, Sternberg PW

[J Vis Exp, 2024]

Chemical communication is vital in organismal health, reproduction, and overall well-being. Understanding the molecular pathways, neural processes, and computations governing these signals remains an active area of research. The nematode Caenorhabditis elegans provides a powerful model for studying these processes as it produces a volatile sex pheromone. This pheromone is synthesized by virgin females or sperm-depleted hermaphrodites and serves as an attractant for males. This protocol describes a detailed method for isolating the volatile sex pheromone from several C. elegans strains (WT strain N2, daf-22, and fog-2) and C. remanei. We also provide a protocol for quantifying the male chemotaxis response to the volatile sex pheromone. Our analysis utilizes measurements such as chemotaxis index (C.I.), arrival time (A.T.), and a trajectory plot to compare male responses under various conditions accurately. This method allows for robust comparisons between males of different genetic backgrounds or developmental stages. Furthermore, the experimental setup outlined here is adaptable to investigating other chemoattraction chemicals.

Wan G et al. (2020) Genetics "A Conserved NRDE-2/MTR-4 Complex Mediates Nuclear RNAi in Caenorhabditis elegans."

Kennedy S, Yan J, Wan G, Pagano DJ, Fei Y

[Genetics, 2020]

Small regulatory RNAs such as siRNAs and piRNAs regulate splicing, transcription, and genome integrity in many eukaryotes. In <i>C. elegans</i>, siRNAs bind nuclear Argonautes (AGOs), which interact with homologous pre-mRNAs to recruit downstream silencing effectors such as NRDE-2 to direct co-transcriptional gene silencing (cTGS or nuclear RNAi). To further our understanding of the mechanism of nuclear RNAi, we conducted IP-Mass Spectrometry on <i>C. elegans</i> NRDE-2. The major NRDE-2 interacting protein identified was the RNA helicase MTR-4. co-IP analyses confirmed a physical association between NRDE-2 and MTR-4. MTR-4 co-localizes with NRDE-2 within the nuclei of most/all <i>C. elegans</i> somatic and germline cells. MTR-4 is required for nuclear RNAi, and interestingly, MTR-4 is recruited to pre-mRNAs undergoing nuclear RNAi via a process requiring nuclear siRNAs, the nuclear AGO HRDE-1, and NRDE-2, indicating that MTR-4 is a component of the <i>C. elegans</i> nuclear RNAi machinery. Finally, we confirm previous reports showing that mammalian HsNRDE2 and HsMTR4 also physically interact. Our data show that the NRDE-2/MTR-4 interactions are evolutionarily conserved and that, in <i>C. elegans</i>, the NRDE-2/MTR-4 complex contributes to siRNA-directed co-transcriptional gene silencing.

Wan QL et al. (2019) Oxid Med Cell Longev "The Effects of Age and Reproduction on the Lipidome of Caenorhabditis elegans."

Pu YZ, Ding AJ, Yang ZL, Wu GS, Luo HR, Wan QL, Zhou XG

[Oxid Med Cell Longev, 2019]

Aging is a complex life process, and a unified view is that metabolism plays key roles in all biological processes. Here, we determined the lipidomic profile of <i>Caenorhabditis elegans</i> (<i>C. elegans</i>) using ultraperformance liquid chromatography high-resolution mass spectrometry (UPLC-HRMS). Using a nontargeted approach, we detected approximately 3000 species. Analysis of the lipid metabolic profiles at young adult and ten-day-old ages among wild-type N2, <i>glp-1</i> defective mutant, and double mutant <i>daf-16;glp-1</i> uncovered significant age-related differences in the total amount of phosphatidylcholines (PC), sphingomyelins (SM), ceramides (Cer), diglycerides (DG), and triglycerides (TG). In addition, the age-associated lipid profiles were characterized by ratio of polyunsaturated (PUFA) over monounsaturated (MUFA) lipid species. Lipid metabolism modulation plays an important role in reproduction-regulated aging; to identify the variations of lipid metabolites during germ line loss-induced longevity, we investigated the lipidomic profiles of long-lived <i>glp-1</i>/notch receptor mutants, which have reproductive deficiency when grown at nonpermissive temperature. The results showed that there was some age-related lipid variation, including TG 40:2, TG 40:1, and TG 41:1, which contributed to the long-life phenotype. The longevity of <i>glp-1</i> mutant was <i>daf-16</i>-dependent; the lipidome analysis of <i>daf-16;glp-1</i> double mutant revealed that the changes of some metabolites in the <i>glp-1</i> mutant were <i>daf-16</i>-dependent, while other metabolites displayed more complex epistatic patterns. We first conducted a comprehensive lipidome analysis to provide novel insights into the relationships between longevity and lipid metabolism regulated by germ line signals in <i>C. elegans</i>.

Wan QL et al. (2022) Nat Commun "Histone H3K4me3 modification is a transgenerational epigenetic signal for lipid metabolism in Caenorhabditis elegans."

Wang C, Wan QL, Zhou Q, Meng X, Yang J, Ye Q, Yin Z, Dai W, Fu X, Luo Z, Zhang ZH, Ju Z

[Nat Commun, 2022]

As a major risk factor to human health, obesity presents a massive burden to people and society. Interestingly, the obese status of parents can cause progeny's lipid accumulation through epigenetic inheritance in multiple species. To date, many questions remain as to how lipid accumulation leads to signals that are transmitted across generations. In this study, we establish a nematode model of C. elegans raised on a high-fat diet (HFD) that leads to measurable lipid accumulation, which can transmit the lipid accumulation signal to their multigenerational progeny. Using this model, we find that transcription factors DAF-16/FOXO and SBP-1/SREBP, nuclear receptors NHR-49 and NHR-80, and delta-9 desaturases (fat-5, fat-6, and fat-7) are required for transgenerational lipid accumulation. Additionally, histone H3K4 trimethylation (H3K4me3) marks lipid metabolism genes and increases their transcription response to multigenerational obesogenic effects. In summary, this study establishes an interaction between a network of lipid metabolic genes and chromatin modifications, which work together to achieve transgenerational epigenetic inheritance of obesogenic effects.

Wan YC et al. (2022) PLoS One "Conservation of Nematocida microsporidia gene expression and host response in Caenorhabditis nematodes."

Troemel ER, Reinke AW, Wan YC

[PLoS One, 2022]

Microsporidia are obligate intracellular parasites that are known to infect most types of animals. Many species of microsporidia can infect multiple related hosts, but it is not known if microsporidia express different genes depending upon which host species is infected or if the host response to infection is specific to each microsporidia species. To address these questions, we took advantage of two species of Nematocida microsporidia, N. parisii and N. ausubeli, that infect two species of Caenorhabditis nematodes, C. elegans and C. briggsae. We performed RNA-seq at several time points for each host infected with either microsporidia species. We observed that Nematocida transcription was largely independent of its host. We also observed that the host transcriptional response was similar when infected with either microsporidia species. Finally, we analyzed if the host response to microsporidia infection was conserved across host species. We observed that although many of the genes upregulated in response to infection are not direct orthologs, the same expanded gene families are upregulated in both Caenorhabditis hosts. Together our results describe the transcriptional interactions of Nematocida infection in Caenorhabditis hosts and demonstrate that these responses are evolutionarily conserved.

Wan L et al. (2019) Environ Microbiol "Bacillus thuringiensis targets the host intestinal epithelial junctions for successful infection of Caenorhabditis elegans."

Sun M, Wan L, Bravo A, Lin J, Soberon M, Du H, Peng D

[Environ Microbiol, 2019]

Pathogenic bacteria use different strategies to infect their hosts, including the simultaneous production of pore forming toxins and several virulence factors that may synergize their pathogenic effects. However, how the pathogenic bacteria are able to break out the host intestinal barrier is poorly understood. The infectious cycle of Bacillus thuringiensis (Bt) bacterium in Caenorhabditis elegans is a powerful model system to study the early stages of the infection process. Bt produces Cry pore-forming toxins during the sporulation phase that are key virulence factors involved in its pathogenesis. In this study, we show that Bt disrupts the intestinal epithelial junctions of C. elegans at early stages of infection allowing Bt bacterium to complete its life cycle in the worm. We further confirmed that the vegetative Bt cells trigger a quorum sensing response that is activated by PlcR regulator, resulting in production of different virulence factors, such as the metalloproteinases ColB and Bmp1, that besides Cry toxins are necessary to disrupt the nematode epithelial junctions causing efficient bacterial host infection and death of the nematode. Our work provides new insights into the pathogenesis of Bt, and highlights the importance of breaking down host epithelial junctions for a successful infection. A similar mechanism could be used by other pathogen-host interactions since epithelial junctions are conserved structures from insects to mammals. This article is protected by copyright. All rights reserved.