Luo Q et al. (2020) RSC Adv "Structural characterization of ginseng oligopeptides and anti-aging potency evaluation in Caenorhabditis elegans."

Wang H, Liu X, Liu J, Luo Q, Liu Z, Zhou Y

[RSC Adv, 2020]

The functions of ginseng polysaccharide have been widely explored, yet, the antiaging activity of ginseng oligopeptides (GOPs) has not been well explored. In the current study, seven novel GOPs were isolated, and their antiaging activity was explored in a Caenorhabditis elegans (C. elegans) model. Of interest, all the GOPs showed lifespan extending effects in C. elegans models. Out of the GOPs treatments, 0.75 mM GOP-1 (EHGEYE) prolonged the N2 nematodes lifespan by 42.5%. Additionally, GOP-1 had a strong free radical-scavenging activity, and up-regulated the survival of the N2 C. elegans under oxidative and thermal stresses. Further study revealed that GOP-1 up-regulated the transcription factor daf-16 and jnk-1 expressions, thus we inferred that GOP-1 promotes the lifespan and stress resistances through a JNK-1-DAF-16 pathway. The current study revealed that the ginseng oligopeptides are potential antiaging agents.

Taub J et al. (1999) Nature "A cytosolic catalase is needed to extend adult lifespan in C. elegans daf-C and clk-1 mutants."

Rothblatt JA, Ma C, Taub J, Lau JF, Chalfie M, Hahn J-H, Hoque R

[Nature, 1999]

The dauer larva is an alternative larval stage in Caenorhabditis elegans which allows animals to survive through periods of low food availability. Well-fed worms live for about three weeks, but dauer larvae can live for at least two months without affecting post-dauer lifespan. Mutations in daf-2 and age-1, which produce a dauer constitutive (Daf-C) phenotype, and in clk-1, which are believed to slow metabolism, markedly increase adult lifespan. Here we show that a ctl-1 mutation reduces adult lifespan in otherwise wild-type animals and eliminates the daf-c and clk-1-mediated extension of adult lifespan. ctl-1 encodes an unusual cytosolic catalase; a second gene, ctl-2, encodes a peroxisomal catalase. ctl-1 messenger RNA is increased in dauer larvae and adults with the daf-c mutations. We suggest that the ctl-1 catalase is needed during periods of starvation, as in the dauer larva, and that its misexpression in daf-c and clk-1 adults extends lifespan. Cytosolic catalase may have evolved to protect nematodes from oxidative damage produced during prolonged dormancy before reproductive maturity, or it may represent a general mechanism for permitting organisms to cope with the metabolic changes that accompany starvation.

Kumar SN et al. (2017) Front Pharmacol "An Antifungal Mechanism of Protolichesterinic Acid from the Lichen Usnea albopunctata Lies in the Accumulation of Intracellular ROS and Mitochondria-Mediated Cell Death Due to Apoptosis in Candida tropicalis."

Kumar SN, Mohandas C

[Front Pharmacol, 2017]

Candida species causes superficial and life-threatening systemic infections and are difficult to treat due to the resistance of these organism to various clinically used drugs. Protolichesterinic acid is a well-known lichen compound. Although the antibacterial activity of protolichesterinic acid has been reported earlier, the antifungal property and its mechanism of action are still largely unidentified. The goal of the present investigation is to explore the anticandidal activity and mechanism of action of protolichesterinic acid, especially against Candida tropicalis. The Minimum Inhibitory Concentration (MIC) value was established through microdilution techniques against four Candida species and out of four species tested, C. tropicalis showed a significant effect (MIC: 2 g/ml). In the morphological interference assay, we observed the enhanced inhibition of hyphae when the cells were treated with protolichesterinic acid. Time-kill assay demonstrated that the maximum rate of killing was recorded between 2 and 6 h. C. tropicalis exposed to protolichesterinic acid exhibited an increased ROS production, which is one of the key factors of fungal death. The rise in ROS was due to the dysfunction of mitochondria caused by protolichesterinic acid. We confirmed that protolichesterinic acid-induced dysfunction of mitochondria in C. tropicalis. The damage of cell membrane due to protolichesterinic acid treatment was confirmed by the influx of propidium iodide and was further confirmed by the release of potassium ions. The treatment of protolichesterinic acid also triggered calcium ion signaling. Moreover, it commenced apoptosis which is clearly evidenced by Annexin V and propidium iodide staining. Interestingly protolichesterinic acid recorded excellent immunomodulatory property when tested against lymphocytes. Finally protolichesterinic acid showed low toxicity toward a normal human cell line Foreskin (FS) normal fibroblast. In in vivo test, protolichesterinic acid significantly enhanced the survival of C. tropicalis infected Caenorhabditis elegans. This investigation proposes that the protolichesterinic acid induces apoptosis in C. tropicalis via the enhanced accumulation of intracellular ROS and mitochondrial damage, which leads fungal cell death via apoptosis. Our work revealed a new key aspect of mechanisms of action of protolichesterinic acid in Candida species. This article is the first study on the antifungal and mechanism of action of protolichesterinic acid in Candida species.

Sijen T et al. (2007) Science "Secondary siRNAs result from unprimed RNA synthesis and form a distinct class."

Steiner FA, Sijen T, Thijssen KL, Plasterk RH

[Science, 2007]

In C. elegans, an effective RNA interference (RNAi) response requires the production of secondary siRNAs by RNA-directed RNA polymerases (RdRPs). We cloned secondary siRNAs from transgenic C. elegans lines expressing a single 22 nucleotide primary siRNA. Several secondary siRNAs start a few nucleotides downstream of the primary siRNA, indicating that non-RISC (RNA-induced silencing complex) cleaved mRNAs are substrates for secondary siRNA production. In lines expressing primary siRNAs with single-nucleotide mismatches, secondary siRNAs do not carry the mismatch, but contain the nucleotide complementary to the mRNA. We infer that RdRPs perform unprimed RNA synthesis. Secondary siRNAs are only of antisense polarity, carry 5'' di- or triphosphates and are only in minority associated with RDE-1, the RNAi-specific argonaute protein. Therefore, secondary siRNAs represent a distinct class of small RNAs. Their biogenesis depends on RdRPs, and we propose that each secondary siRNA is an individual RdRP product.

De Domenico I et al. (2011) Cell Metab "The role of ubiquitination in hepcidin-independent and hepcidin-dependent degradation of ferroportin."

Yang B, Kaplan J, Hamza I, Korolnek T, Lo E, De Domenico I, Ward DM

[Cell Metab, 2011]

The iron exporter ferroportin (Fpn) is essential to transfer iron from cells to plasma. Systemic iron homeostasis in vertebrates is regulated by the hepcidin-mediated internalization of Fpn. Here, we demonstrate a second route for Fpn internalization; when cytosolic iron levels are low, Fpn is internalized in a hepcidin-independent manner dependent upon the E3 ubiquitin ligase Nedd4-2 and the Nedd4-2 binding protein Nfdip-1. Retention of cell-surface Fpn through reductions in Nedd4-2 results in cell death through depletion of cytosolic iron. Nedd4-2 is also required for internalization of Fpn in the absence of ferroxidase activity as well as for the entryof hepcidin-induced Fpn into the multivesicularbody. C. elegans lacks hepcidin genes, and C. elegans Fpn expressed in mammalian cells is not internalized by hepcidin but is internalized in response to iron deprivation in a Nedd4-2-dependent manner, supporting the hypothesis that Nedd4-2-induced internalization of Fpn is evolutionarily conserved.

Sasata RJ et al. (2004) J Biol Chem "Domain swapping localizes the structural determinants of regioselectivity in membrane-bound fatty acid desaturases of Caenorhabditis elegans."

Loewen MC, Covello PS, Reed DW, Sasata RJ

[J Biol Chem, 2004]

Most fatty acid desaturases are members of a large superfamily of integral membrane, O2-dependent iron-containing enzymes that catalyze a variety of oxidative modifications to lipids. Sharing a similar primary structure and membrane topology, these enzymes are broadly categorized according to their positional specificity or regioselectivity, which designates the preferred position for substrate modification. To investigate the structural basis of regioselectivity in membrane-bound desaturases, the Caenorhabditis elegans omega-3 (FAT-1) and delta-12 (FAT-2) desaturases were used as a model system. With the use of unnatural substrates, the regioselectivity of C. elegans FAT-2 was clearly defined as nu+3, i.e., it measures three carbons from an existing double bond. The structural basis for nu+3 and omega-3 regioselectivities was examined through construction and expression of chimeric DNA sequences based on FAT-1 and FAT-2. Each sequence was divided into seven domains, and chimeras were constructed in which specific domains were replaced with sequence from the other desaturase. When tested by expression in yeast using exogenously supplied substrates, chimeric sequences were found in which domain swapping resulted in a change of regioselectivity from nu+3 to omega-3 and vice versa. In this way, the structural determinants of regioselectivity in FAT-1 and FAT-2 have been localized to two interdependent regions: a relatively hydrophobic region between the first two histidine boxes, and the C-terminal region.

Wulczyn FG et al. (2007) FASEB J "Post-transcriptional regulation of the let-7 microRNA during neural cell specification."

Rybak A, Strehle M, Seiler A, Kwidzinski E, Smirnova L, Schumacher S, Brandt C, Wulczyn FG, Ninnemann O, Nitsch R

[FASEB J, 2007]

The let-7 miRNA regulates developmental timing in C. elegans and is an important paradigm for investigations of miRNA functions in mammalian development. We have examined the role of miRNA precursor processing in the temporal control and lineage specificity of the let-7 miRNA. In situ hybridization (ISH) in E9.5 mouse embryos revealed early induction of let-7 in the developing central nervous system. The expression pattern of three let-7 family members closely resembled that of the brain-enriched miRNAs mir-124, mir-125 and mir-128. Comparison of primary, precursor, and mature let-7 RNA levels during both embryonic brain development and neural differentiation of embryonic stem cells and embryocarcinoma (EC) cells suggest post-transcriptional regulation of let-7 accumulation. Reflecting these results, let-7 sensor constructs were strongly down-regulated during neural differentiation of EC cells and displayed lineage specificity in primary cells. Neural differentiation of EC cells was accompanied by an increase in let-7 precursor processing activity in vitro. Furthermore, undifferentiated and differentiated cells contained distinct precursor RNA binding complexes. A neuron-enhanced binding complex was shown by antibody challenge to contain the miRNA pathway proteins Argonaute1 and FMRP. Developmental regulation of the processing pathway correlates with differential localization of the proteins Argonaute, FMRP, MOV10, and TNRC6B in self-renewing stem cells and neurons.--Wulczyn, F. G., Smirnova, L., Rybak, A., Brandt, C., Kwidzinski, E., Ninnemann, O., Strehle, M., Seiler, A., Schumacher, S., Nitsch, R. Post-transcriptional regulation of the let-7 microRNA during neural cell specification.

Clovis Y et al. (2016) MicroPubl Biol "Mutations in KCNQ potassium channels cause pharyngeal pumping defects in C. elegans."

Roberts B, Webb A, Clovis Y, Turner C

[MicroPubl Biol, 2016]

Pumps were stimulated with 10mM 5HT in M9 recorded as electropharyngeograms (EPGs) for 2 minutes in a NemaMetrix ScreenChip, and analyzed using NemAnalysis software (NemaMetrix). The null mutant strains kqt-1(aw3) and kqt-3 (aw1) were kindly donated by Dr. Aguan Wei (Wei et al., 2002) A) Pump frequency in kqt-1(aw3) animals was significantly lower than in N2s, while kqt-3(aw1) worms showed an increase in pump frequency (*p<0.05; ***p<0.01; 1-tailed Mann-Whitney U-test; n = 21-23 worms in each strain). B) Microfluidic EPG recordings show that pumping pattern in kqt-1(aw3) mutants is arrhythmic, with frequent drops in frequency. C) Overlay of first 50 pumps of recordings show that pump duration is higher in kqt-1(aw3) and kqt-3(aw1) animals than in N2s. Pumps are showed aligned on E spikes, which occur when the pharynx is fully contracted. D) Duration histogram illustrating the probability of occurrence of inter-pump interval (E to E duration) for each mutant strain. Histograms were binned to 4 ms width and normalized to reach an area underneath the curve equal to 1 (duration 100% likelihood to occur). In kqt-1(aw3)) animals, the time between two pumps is significantly increased compared to N2s (p < 0.01).

Iwatsubo T (2007) Neuropathology "Pathological biochemistry of alpha-synucleinopathy."

Iwatsubo T

[Neuropathology, 2007]

Lewy bodies (LBs) are hallmark lesions in the brains of patients with Parkinson''s disease (PD) and dementia with Lewy bodies (DLB). We raised a monoclonal antibody LB509 against purified LBs from the brains of patients with DLB that strongly immunolabled LBs, and found that alpha-synuclein is one of the major components of LBs. Thus, the deposition of alpha-synuclein, an abundant presynaptic brain protein, as fibrillary aggregates in affected neurons or glial cells, was highlighted as a hallmark lesion of a subset of neurodegenerative disorders, including PD, DLB and multiple system atrophy collectively referred to as synucleinopathies. Importantly, the identification of missense mutations in and multiplication of alpha-synuclein gene in some pedigrees of familial PD has strongly implicated alpha-synuclein in the pathogenesis of PD and other synucleinopathies. We then examined the specific posttranslational modifications that characterize and underlie the aggregation of alpha-synuclein in synucleinopathy brains by mass spectrometry and using a specific antibody, and found that serine 129 of alpha-synuclein deposited in synucleinopathy lesions is selectively and extensively phosphorylated. Furthermore we generated transgenic C. elegans overexpressing alpha-synuclein in neurons, and found that overexpression of familial PD-linked mutant form of alpha-synuclein impairs functions of dopamine neurons. These findings collectively underscore the importance of deposition of alpha-synuclein as well as its phosphorylation in the pathogenesis of alpha-synucleinopathies.

Wang Y et al. (2013) Am J Physiol Regul Integr Comp Physiol "Phylogenetic, expression, and functional analyses of anoctamin homologs in Caenorhabditis elegans."

Miyamoto MM, Bruggeman B, Leung CK, Hill-Harfe K, Iribarne D, Harfe BD, Choe KP, Wang Y, Alam T, Lopez AJ

[Am J Physiol Regul Integr Comp Physiol, 2013]

Ca(2+)-activated Cl(-) channels (CaCCs) are critical to processes such as epithelial transport, membrane excitability, and signal transduction. Anoctamin, or TMEM16, is a family of 10 mammalian transmembrane proteins, 2 of which were recently shown to function as CaCCs. The functions of other family members have not been firmly established, and almost nothing is known about anoctamins in invertebrates. Therefore, we performed a phylogenetic analysis of anoctamins across the animal kingdom and examined the expression and function of anoctamins in the genetically tractable nematode Caenorhabditis elegans. Phylogenetic analyses support five anoctamin clades that are at least as old as the deuterostome/protosome ancestor. This includes a branch containing two Drosophila paralogs that group with mammalian ANO1 and ANO2, the two best characterized CaCCs. We identify two anoctamins in C. elegans (ANOH-1 and ANOH-2) that are also present in basal metazoans. The anoh-1 promoter is active in amphid sensory neurons that detect external chemical and nociceptive cues. Within amphid neurons, ANOH-1::GFP fusion protein is enriched within sensory cilia. RNA interference silencing of anoh-1 reduced avoidance of steep osmotic gradients without disrupting amphid cilia development, chemotaxis, or withdrawal from noxious stimuli, suggesting that ANOH-1 functions in a sensory mode-specific manner. The anoh-2 promoter is active in mechanoreceptive neurons and the spermatheca, but loss of anoh-2 had no effect on motility or brood size. Our study indicates that at least five anoctamin duplicates are evolutionarily ancient and suggests that sensory signaling may be a basal function of the anoctamin protein family.