Zhou, Yiwen et al. (2017) International Worm Meeting "Disentangling the CYP-eicosanoids dependent regulation of the pharyngeal pumping in Caenorhabditis elegans."

Zhou, Yiwen, Menzel, Ralph

[International Worm Meeting, 2017]

Cytochrome P450 (CYP)-dependent eicosanoids are epoxygenated and/or hydroxylated metabolites of long-chain polyunsaturated fatty acids (LC-PUFAs). They are important lipid mediators participating in numerous physiological and pathological processes in mammalian systems. The CYP-eicosanoid cascade is initiated by the release of LC-PUFA from cell membrane phospholipids by a phospholipase A2, it follows the CYP-dependent eicosanoids biosynthesis and the interaction of eicosanoids with so far unknown cell-surface receptors that are expected to be part of the G-protein coupled receptor (GPCR) family. Recent studies revealed that the nematode Caenorhabditis elegans also produces a broad spectrum of CYP eicosanoids, in particular, epoxy- and hydroxy-metabolites derived predominantly from eicosapentaenoic acid (EPA). One revealed physiological function in the nematode is involved in the regulation of pharyngeal pumping. 17,18-epoxyeicosatetraenic acid (17,18-EEQ), as the most abundant CYP eicosanoid in C. elegans, mimics the stimulating effect of serotonin and rescues LC-PUFA deficient strains from their pumping impairments. Here we tested the hypothesis that 17,18-EEQ serves as second messenger in the underlying signaling pathway and exerts its effect by binding to a specific membrane G-protein-coupled receptor in the pharynx of nematode. We performed a biased screen of selected gene knockout strains displaying behavioral impairments in the pharyngeal pumping by feeding these worms with red fluorescent beads. The results showed that the knockout strains nmur-2(ok3502), npr-24(ok3192), exp-2(sa26), eat-2(ad465) and egl-30(ad806), respectively, were unable to respond to 17,18-EEQ treatment. Moreover, manual counting of the pharyngeal pumping frequency in the presence or absence of supplemental 17,18-EEQ was performed. Two of the candidate genes are coding for GPCRs, which indicates that these proteins might be involved in the 17,18-EEQ signaling of C. elegans.

Zhou, Yiwen et al. (2017) International Worm Meeting "Stereospecific bioactivity of the eicosanoid 17,18-epoxyeicosatetraenoic acid on the pharyngeal pumping of Caenorhabditis elegans."

Zhou, Yiwen, Menzel, Ralph

[International Worm Meeting, 2017]

17,18-epoxyeicosatetraenic acid (17,18-EEQ), the most abundant cytochrome P450 (CYP)-eicosanoid in C. elegans, is a potential signaling molecule in the regulation of pharyngeal pumping activity. Here we tested the hypothesis that stereo-discrimination of this chiral molecule may hint the existence of a receptor in the pharyngeal muscle and/or neuronal cells. We analyzed the effect of short-term incubation in both well fed and starved condition and found that the stereoisomer 17(R),18(S)-EEQ, clearly rescued impairments of pharyngeal pumping in D-6 fatty acid desaturase mutant strain fat-3(wa22). After treatment with the 17(S),18(R)-EEQ stereoisomer, however, we found no effect on pumping activity. In addition, we will analyze the total endogenous eicosanoid stereoisomer content of C. elegans by chiral LC/MS-MS to see whether or not only specific stereoisomers are endogenous resources. 17(R),18(S)-EEQ was more active in ceeh-1(ok3153) mutant background in comparison to other stains. We suspect that ceeh-1(ok3153), failing to produce a functional active soluble hydrolase (sEH), is unable to efficiently catalyze the hydrolysis of 17,18-EEQ to the corresponding diol (17,18-DHEQ), which we found correlated with a loss of function of this signaling molecule. 17,18-DHEQ treatment was inactive in a C. elegans' pumping assay.

Zhou, Yiwen et al. (2013) International Worm Meeting "Biological function of PUFA-derived eicosanoids in Caenorhabditis elegans."

Steinberg, Chrisitan, Yin, Lihong, Ju, Jingjuan, Nehk, Erik, Menzel, Ralph, Zhou, Yiwen

[International Worm Meeting, 2013]

Mammals and C. elegans share similar basic mechanisms of cytochrome P450 (CYP)-dependent eicosanoid formation. These eicosanoids are sets of regioisomeric epoxy- and hydroxy-derivatives derived from, typically, 20-carbon polyunsaturated fatty acids (PUFA). So far as is known from GFP expression experiments, C. elegans produces its eicosanoids in the marginal cells. Here we tested the hypothesis that these signaling molecules known to modulate the contractility of cardiomyocytes and vascular smooth muscle in mammals serve as regulators of muscle activity in the nematode, too. In mammals diet primarily controls PUFA and eicosanoid pattern, whereas C. elegans can synthesize all PUFA de novo. Because this synthesis requires the activity of several specific desaturases, their loss of function were found to cause dramatic changes in derived eicosanoid pattern. First, we examined the frequency of pharyngeal pumping of wild type and several mutant strains under different conditions, with and without food and in response to neurotransmitters (serotonin, glutamate, octopamine, and acetylcholine). The obtained results suggest that eicosanoids seem to be not essential for the reactions to neurotransmitters or food availability. Second, we analyzed the effect of supplementing the medium with different eicosanoids, both in the wild type and PUFA- or CYP-deficient mutant strains. Here we found a clear rescue of impairments of pharyngeal pumping as well as locomotion of the fat-3(wa22) strain, not able to produce any 20-carbon eicosanoid, and emb-8(hc69), characterized by an almost complete depletion of active NADPH-dependent CYP-reductase, an essential part of each CYP monooxygenase system in C. elegans. The CYP-derived metabolism of PUFA to eicosanoids is also strictly dependent on sufficient oxygen supply. In this respect we could show that eicosanoid pattern modulated C. elegans' response to anoxia. The removal of oxygen resulted in a significant higher initial sensitivity of eicosanoid-free or -depleted strains in comparison to the wild type, but became marginalized after long-time exposure.

Savini M et al. (2019) Cell "Does Autophagy Promote Longevity? It Depends."

Wang MC, Savini M

[Cell, 2019]

Zhou etal. challenge the well-known beneficial effect of autophagy in promoting longevity. Evidence presented demonstrate that autophagy induction coupled with increased mitochondrial permeability is detrimental to organismal health in both the nematode Caenorhabditis elegans and mammals.

Zhou Z et al. (2001) Cell "CED-1 is a transmembrane receptor that mediates cell corpse engulfment in C. elegans."

Zhou Z, Horvitz HR, Hartweig EA, Hartwieg E

[Cell, 2001]

We cloned the C. elegans gene ced-1, which is required for the engulfment of cells undergoing programmed cell death. ced-1 encodes a transmembrane protein similar to human SREC (Scavenger Receptor from Endothelial Cells). We showed that ced-1 is expressed in and functions in engulfing cells. The CED-1 protein localizes to cell membranes and clusters around neighboring cell corpses. CED-1 failed to cluster around cell corpses in mutants defective in the engulfment gene ced-7. Motifs in the intracellular domain of CED-1 known to interact with PTB and SH2 domains were necessary for engulfment but not for clustering. Our results indicate that CED-1 is a cell surface phagocytic receptor that recognizes cell corpses. We suggest that the ABC transporter CED-7 promotes cell corpse recognition by CED-1, possibly by exposing a phospholipid ligand on the surfaces of cell corpses.AD - Howard Hughes Medical Institute, Department of Biology, Building 68, Room 425, Massachusetts Institute of Technology, 77 Massachusetts Avenue, Cambridge, MA 02139, USA.FAU - Zhou, ZAU - Zhou ZFAU - Hartwieg, EAU - Hartwieg EFAU - Horvitz, H RAU - Horvitz HRLA - engSI - GENBANK/AF332568PT - Journal ArticleCY - United StatesTA - CellJID - 0413066RN - 0 (ATP-Binding Cassette Transporters)RN - 0 (CED-7 protein)RN - 0 (Membrane Proteins)RN - 0 (Receptors, Immunologic)RN - 0 (ced-1 protein, C. elegans)RN - 0 (scavenger receptor)RN - 62229-50-9 (Epidermal Growth Factor)SB - IM

Darnet S et al. (2019) J Lipid Res "Worming our way toward multiple evolutionary origins of convergent sterol pathways."

Fliesler SJ, Schaller H, Darnet S

[J Lipid Res, 2019]

Sterols represent one of the most ubiquitous and diverse classes of biological molecules derived from the common precursor mevalonic acid. While there are thematically similar modes by which various organisms synthesize sterols, there also are some unique twists in the pathways by which such organisms produce sterols as well as differences in the chemical nature of the dominant resident sterol present at steady-state in a given organism or cell type. In this issue of Journal of Lipid Research, David Nes and colleagues (Zhou et al. (1)) present a compelling and novel story, wherein they have elucidated a previously unknown alternative biosynthetic pathway utilized by nematodes (roundworms, of which Caenorhabditis elegans is an exemplar) to generate C4methyl sterols. This provides an evolutionary "missing link" along the continuum from prokaryotes to eukaryotes or eventually a singular divergent evolution of roundworms with regard to diversification of sterols and the metabolic routes accessible to them to achieve such diversity.

Tao Xu (2008) C.elegans Neuronal Development Meeting "Towards a better understanding of docking/priming of dense core vesicles in C. elegans neurons"

Tao Xu

[C.elegans Neuronal Development Meeting, 2008]

Neuropeptides are packed into dense core vesicles (DCVs) and play critical roles in synaptic signaling. Before a DCV undergoes Ca-triggered exocytosis, it has to become fusion-competent through a so-called docking/priming step. Although a few molecules have been suggested to be involved in the docking/priming of DCVs, our understanding of the mechanism of this process is far from complete. Recently, we have developed high resolution functional assays to monitor the docking/priming process of DCVs in C. elegans neurons (Zhou et al., 2007, Neuron). Combining these techniques with the power of genetic manipulation in C. elegans model systems allows the illustration of sequential events in the docking/priming of DCVs at an unprecedented systematic level. I will summarize our recent progress towards a clearer picture of docking/priming of DCVs through analyzing the C. elegans mutants which are implicated to affect docking/priming.

D Omura et al. (1999) International C. elegans Meeting "A screen for mutations that affect the localization of CED-4"

F Chen, B Horvitz, B Hersh, D Omura

[International C. elegans Meeting, 1999]

In the programmed cell death pathway, ced-4 is a key activator of the C. elegans caspase ced-3 . Genetically, ced-4 is upstream of ced-3 and is necessary for normal programmed cell death to occur. egl-1 and ced-9 act upstream of ced-4 in the genetic pathway and are involved in activating and inhibiting ced-4 activity, respectively. Previous work has shown that the localization of ced-4 seems intimately tied to its activity. In cells that are not undergoing programmed cell death, CED-4 is localized to mitochondrial membrane surfaces. When these cells are induced to die by overexpressing egl-1 or by ced-9 loss-of-function, CED-4 is localized to the perinuclear membrane 1 . CED-4 localization appears to correlate with the life-or-death decision of a cell, but how and why the localization occurs is unknown. When overexpressed, a CED-4::GFP fusion protein appears to localize to the mitochondria and perinuclear region of cells that are not undergoing programmed cell death. To identify factors important for the localization of CED-4, we will screen for mutants in which this CED-4::GFP fusion protein fails to localize to the perinucleus of viable cells. 1 Hersh, B., Chen, F., Conradt, B., Zhou, Z., and Horvitz, HR (1999) 12th International C. elegans Meeting

Frederick J Tan et al. (2004) West Coast Worm Meeting "Functions of the Outer Mitochondrial Membrane Protein CED-9"

R Blake Hill, Andrew Z Fire, Frederick J Tan

[West Coast Worm Meeting, 2004]

CED-9 (CEll Death abnormal) negatively regulates the programmed cell death pathway in C. elegans . This membrane associated pro-survival protein prevents the activation of the CED-3 caspase. Loss of function ced-9 animals arrest at early embryogenesis, presumably dying from ectopic cell deaths. Conversely, gain of function animals appear healthy, albeit with extra cells (Hengartner, Ellis and Horvitz, 1992). These effects have been ascribed to the ability of CED-9 to sequester the CED-4/CED-3 caspase complex at the mitochondria (Chen, et al. , 2000). We hope to understand the structural features of CED-9 that participate in its function. To this end, we are assaying the activity of various CED-9 mutants and derivatives for ability to prevent cell death and respond to appropriate modulating signals. A question that we consider to be central is whether the C-terminal transmembrane domain of CED-9 serves only as a targeting sequence to the mitochondrion, or plays a more active role. We have demonstrated that this domain is essential for mitochondrial localization and plays some role in the function of CED-9. Distinction between localization and other structural and functional roles is in progress. Hengartner MO, Ellis RE and HR Horvitz. 1992. Caenorhabditis elegans gene ced-9 protects cells from programmed cell death. Nature 356 , 494-499. Chen F, Hersh BM, Conradt B, Zhou Z, Riemer D, Gruenbaum Y, and HR Horvitz. 2000. Translocation of C. elegans CED-4 to Nuclear Membranes During Programmed Cell Death. Science 287 , 1485-1489.

Schmidt, Minna Y. et al. MicroPubl Biol

Lithgow, Gordon J., Chamoli, Manish, Andersen, Julie K., Schmidt, Minna Y.

[MicroPubl Biol, 2021]

Parkinson's disease (PD) patients have been shown to benefit greatly from intense physical activity (Schenkman et al. 2018). Recent studies have demonstrated that exercise causes changes in the levels of alpha-synuclein aggregate species, a hallmark of PD, in different mammalian animal models (Koo and Cho 2017; Shin et al. 2017; Zhou et al. 2017; Minakaki et al. 2019). However, questions still remain about how exercise affects specifically native alpha-synuclein protein species directly after the cessation of exercise and the longer-term downstream effects which exercise may have on organismal health. It was recently discovered that periods of thrashing in liquid solution, otherwise called swimming exercise, in C. elegans worms, induces many mechanisms invoked during mammalian exercise (Laranjeiro et al. 2017). This has provided an avenue for studying exercise conditions in various C. elegans models of neurodegeneration (Laranjeiro et al. 2019). In order to study the effect of exercise on native human alpha-synuclein protein species, we utilized the NL5901- pkIs2386 worm model of Parkinson's which contains human alpha-synuclein tagged to a yellow fluorescent protein (YFP) in the muscle cells (van Ham et al. 2008). We performed tissue analysis via Blue Native (BN) page westerns and confocal microscopy. In addition, because pharyngeal pumping is decreased while worms are swimming, we controlled for this effect by exposing worms in parallel to a period of food restriction (FR) conditions (Vidal-Gadea et al. 2012). We also performed thrashing assays to assess longer term downstream behavioral effects on the animals after either exercise or food restriction conditions.