Liu W et al. (2016) Neurochem Int "Development of a neuroprotective potential algorithm for medicinal plants."

Dain JA, DaSilva NA, Zhang L, Rose KN, Wan C, Johnson SL, Liu W, Ma H, Seeram NP

[Neurochem Int, 2016]

Medicinal plants are promising candidates for Alzheimer's disease (AD) research but there is lack of systematic algorithms and procedures to guide their selection and evaluation. Herein, we developed a Neuroprotective Potential Algorithm (NPA) by evaluating twenty-three standardized and chemically characterized Ayurvedic medicinal plant extracts in a panel of bioassays targeting oxidative stress, carbonyl stress, protein glycation, amyloid beta (A) fibrillation, acetylcholinesterase (AChE) inhibition, and neuroinflammation. The twenty-three herbal extracts were initially evaluated for: 1) total polyphenol content (Folin-Ciocalteu assay), 2) free radical scavenging capacity (DPPH assay), 3) ferric reducing antioxidant power (FRAP assay), 4) reactive carbonyl species scavenging capacity (methylglyoxal trapping assay), 5) anti-glycative effects (BSA-fructose, and BSA-methylglyoxal assays) and, 6) anti-A fibrillation effects (thioflavin-T assay). Based on assigned index scores from the initial screening, twelve extracts with a cumulative NPA score 40 were selected for further evaluation for their: 1) inhibitory effects on AChE activity, 2) in vitro anti-inflammatory effects on murine BV-2 microglial cells (Griess assay measuring levels of lipopolysaccharide-induced nitric oxide species), and 3) in vivo neuroprotective effects on Caenorhabditis elegans post induction of A1-42 induced neurotoxicity and paralysis. Among these, four extracts had a cumulative NPA score 60 including Phyllanthus emblica (amla; Indian gooseberry), Mucuna pruriens (velvet bean), Punica granatum (pomegranate) and Curcuma longa (turmeric; curcumin). These extracts also showed protective effects on H2O2 induced cytotoxicity in differentiated cholinergic human neuronal SH-SY5Y and murine BV-2 microglial cells and reduced tau protein levels in the SH-SY5Y neuronal cells. While published animal data support the neuroprotective effects of several of these Ayurvedic medicinal plant extracts, some remain unexplored for their anti-AD potential. Therefore, the NPA may be utilized, in part, as a strategy to help guide the selection of promising medicinal plant candidates for future AD-based research using animal models.

Liu W et al. (2017) Sci Rep "Spatiotemporal expression profiling of long intervening noncoding RNAs in Caenorhabditis elegans."

Ma X, Liu W, Liu X, Lu Y, Chen S, Yu E

[Sci Rep, 2017]

To better understand the biological function of long noncoding RNAs, it is critical to determine their spatiotemporal expression patterns. We generated transgenic reporter strains for 149 out of the 170 annotated C. elegans long intervening noncoding RNAs (lincRNAs) and profiled their temporal activity. For the 68 lincRNAs with integrated reporter lines, we profiled their expression at the resolution of single cells in L1 larvae, and revealed that the expression of lincRNAs is more specific, heterogeneous and at lower level than transcription factors (TFs). These expression patterns can be largely attributed to transcriptional regulation because they were observed in assays using reporters of promoter activity. The spatial expression patterns of the 68 lincRNAs were further examined in 18 tissue categories throughout eight developmental stages. We compared the expression dynamics of lincRNAs, miRNAs and TFs during development. lincRNA and miRNA promoters are less active at embryo stage than those of TFs, but become comparable to TFs after embryogenesis. Finally, the lincRNA gene set shows a similar tissue distribution to that of miRNAs and TFs. We also generated a database, CELE, for the storage and retrieval of lincRNA reporter expression patterns and other relevant information. The data and strains described here will provide a valuable guide and resource for future functional exploration of C. elegans lincRNAs.

Liu W et al. (2015) J Basic Microbiol "Isolation, identification, and characterization of the nematophagous fungus Monacrosporium salinum from China."

Yi LX, Sun LJ, Wei S, Peng JW, Chen MY, Xu Q, Li X, Xu CL, Cai KZ, Han Y, Wang H, Zhao MW, Yang J, Liu W, Li D, Chen CR, Li Q, Li XS, Xie Q, Wang BB, Zheng TH, Wu JY

[J Basic Microbiol, 2015]

Nematophagous fungi are considered to have the best potential as biological agents for the control of gastrointestinal nematodes in domestic animals. However, relatively few studies have been conducted with the genus Monacrosporium, especially with strains native to China. In the present study, we isolated and identified nematophagous fungi from fresh sheep feces. A pure fungal strain was molecularly characterized, and its nematophagous activity was evaluated. The morphological plasticity of the isolated strain, as well as its interaction with the nematode targets, was observed by scanning electron microscopy of the infected Trichostrongylus colubriformis L3 and the free-living nematode Caenorhabditis elegans. Three isolated fungal strains from the 30 fresh fecal samples of sheep from Inner Mongolia, China exhibited predatory activity; however, only a single strain was successfully purified (SF 0459). The SF 0459 strain was characterized by morphological analysis of its conidia and sequencing of its ITS1-5.8S rDNA-ITS2 region. This strain was identified to be Monacrosporium salinum (GenBank ID: KP036623). Nematophagous fungus helper bacteria were found at the interaction points between fungi and nematodes. The percentage of live T. colubriformis L3 was reduced by 83.79-88.69% based on the in vitro assay.

Liu W et al. (2016) Anticancer Agents Med Chem "Autophagy inhibits apoptosis induced by agrocybe aegerita lectin in hepatocellular carcinoma."

Liu W, Ye X, Sun H, Yu W, Yang Q, Yu G, Jin Y, Shrestha A

[Anticancer Agents Med Chem, 2016]

BACKGROUND: Lectins are carbohydrate-binding proteins that exhibit remarkable anti-tumor activities by inducing apoptotic or autophagic cell death. However, the relationship between apoptosis and autophagy induced by lectins has rarely been reported. Agrocybe aegerita lectin (AAL), a lectin isolated from the fungus Agrocybe aegerita, exerts antitumor activity through apoptosis. METHOD: Growth inhibition of cancer cells by AAL was determined using the CCK-8 kit and the trypan blue assay and was evaluated based on cell morphology. Cell autophagy was studied using western blotting, acridine orange straining, transmission electron microscopy, and transient transfection of pEGFP-LC3 plasmids. We also evaluated AAL-induced autophagy in Caenorhabditis elegans. Apoptosis was studied using flow cytometry. We also identified the antitumor effects of co-treatment of AAL with chloroquine (CQ) in vitro and in vivo. RESULTS: AAL-treated cell lines showed accumulation of microtubule-associated protein light chain 3 II (LC3-II), formation of EGFP-LC3 puncta and acidic autophagic vacuoles (AVOs), and the induction of autophagosomes. Inhibition of autophagy could enhance apoptosis induced by AAL in hepatocellular carcinoma (HCC) cells. Furthermore, AAL and chloroquine were used in a murine in situ HCC model, which revealed that co-therapy (AAL and chloroquine) resulted in an enhanced antitumor effect compared to AAL treatment alone. CONCLUSION: Our findings suggest that inhibition of autophagy exerts a synergistic effect on the antitumor activity of AAL and may be a helpful strategy for reducing the dosage of lectin used in antitumor therapy. The autophagy inhibitor may be a synergist of certain antitumor drugs that can induce both apoptosis and autophagy.

Liu W et al. (2018) Biomolecules "Functional Annotation of Caenorhabditis elegans Genes by Analysis of Gene Co-Expression Networks."

Zhao W, Zou Y, Zheng H, Xu Z, Liu W, Li L, Zhang Y, Zhong Y, Cai S, Wang S, He Y, Tu W

[Biomolecules, 2018]

<i>Caenorhabditis elegans</i> (<i>C. elegans</i>) is a well-characterized metazoan, whose transcriptome has been profiled in different tissues, development stages, or other conditions. Large-scale transcriptomes can be reused for gene function annotation through systematic analysis of gene co-expression relationships. We collected 2101 microarray data from National Center for Biotechnology Information Gene Expression Omnibus (NCBI GEO), and identified 48 modules of co-expressed genes that correspond to tissues, development stages, and other experimental conditions. These modules provide an overview of the transcriptional organizations that may work under different conditions. By analyzing higher-order module networks, we found that nucleus and plasma membrane modules are more connected than other intracellular modules. Module-based gene function annotation may help to extend the candidate cuticle gene list. A comparison with other published data validates the credibility of our result. Our findings provide a new source for future gene discovery in <i>C. elegans</i>.

Liu W et al. (2015) Chemistry "Site-Selective and Metal-Free Aliphatic CH Oxidation Enabled Synthesis of ([5,24,25-D3]) -(25S)-(7) -Dafachronic acid."

Li T, Chen J, Li X, Lei X, Dong M, Liu W

[Chemistry, 2015]

Steroid hormones play significant roles in both worms and mammalians. (25S)-(7) -Dafachronic acid ((7) -DA, 1) is a member of the dafachronic acid hormonal series that regulates both development and lifespan of C. elegans. Despite its importance, effective tools for the illumination of its mode of action are lacking. Herein, we report an efficient synthesis of trideuterated (7) -DA, ([5,24,25-D3]) -(25S)-(7) -dafachronic acid ([D3 ]-(7) -DA, 2), as a useful chemical tool for subsequent biological studies. Key steps for this bioinspired synthesis approach include site-selective aliphatic CH oxidation mediated by methyl(trifluoromethyl)dioxirane (TFDO), and the iridium/phosphine-oxazoline-catalyzed late-stage asymmetric deuterium reduction.

Liu W et al. (2020) Aging (Albany NY) "Verapamil extends lifespan in Caenorhabditis elegans by inhibiting calcineurin activity and promoting autophagy."

Xia C, Bao K, Hu Z, Mao Z, Zhang L, Lin H, Li J, Jiang B, Liu W, Li W

[Aging (Albany NY), 2020]

Previous evidence has revealed that increase in intracellular levels of calcium promotes cellular senescence. However, whether calcium channel blockers (CCBs) can slow aging and extend lifespan is still unknown. In this study, we showed that verapamil, an L-type calcium channel blocker, extended the <i>Caenorhabditis elegans</i> (<i>C. elegans</i>) lifespan and delayed senescence in human lung fibroblasts. Verapamil treatment also improved healthspan in <i>C. elegans</i> as reflected by several age-related physiological parameters, including locomotion, thrashing, age-associated vulval integrity, and osmotic stress resistance. We also found that verapamil acted on the 1 subunit of an L-type calcium channel in <i>C. elegans</i>. Moreover, verapamil extended worm lifespan by inhibiting calcineurin activity. Furthermore, verapamil significantly promoted autophagy as reflected by the expression levels of LGG-1/LC3 and the mRNA levels of autophagy-related genes. In addition, verapamil could not further induce autophagy when <i>tax-6</i>, calcineurin gene, was knocked down, indicating that verapamil-induced lifespan extension is mediated via promoting autophagy processes downstream of calcineurin. In summary, our study provided mechanistic insights into the anti-aging effect of verapamil in <i>C. elegans</i>.

Liu W et al. (2011) Nucleic Acids Res "Structural basis for nematode eIF4E binding an m(2,2,7)G-Cap and its implications for translation initiation."

Darzynkiewicz E, Jones DN, Stepinski J, Jankowska-Anyszka M, Dickson L, Davis RE, Liu W, Piecyk K, Niedzwiecka A, Wallace A, Kieft J, Zhao R, Stolarski R

[Nucleic Acids Res, 2011]

Metazoan spliced leader (SL) trans-splicing generates mRNAs with an m(2,2,7)G-cap and a common downstream SL RNA sequence. The mechanism for eIF4E binding an mG-cap is unknown. Here, we describe the first structure of an eIF4E with an m(2,2,7)G-cap and compare it to the cognate mG-eIF4E complex. These structures and Nuclear Magnetic Resonance (NMR) data indicate that the nematode Ascaris suum eIF4E binds the two different caps in a similar manner except for the loss of a single hydrogen bond on binding the m(2,2,7)G-cap. Nematode and mammalian eIF4E both have a low affinity for m(2,2,7)G-cap compared with the mG-cap. Nematode eIF4E binding to the mG-cap, m(2,2,7)G-cap and the m(2,2,7)G-SL 22-nt RNA leads to distinct eIF4E conformational changes. Additional interactions occur between Ascaris eIF4E and the SL on binding the m(2,2,7)G-SL. We propose interactions between Ascaris eIF4E and the SL impact eIF4G and contribute to translation initiation, whereas these interactions do not occur when only the m(2,2,7)G-cap is present. These data have implications for the contribution of 5'-UTRs in mRNA translation and the function of different eIF4E isoforms.

Liu W et al. (2022) Acta Biomater "Composite of gold nanoclusters and basified human serum albumin significantly boosts the inhibition of Alzheimer's β-amyloid by photo-oxygenation"

Liu W, Zhang H, Sun Y, Dong X

[Acta Biomater, 2022]

Photo-oxygenation has become an effective way to inhibit Alzheimer's &#946;-amyloid protein (A&#946;) fibrillogenesis, which involves oxidative modification of A&#946; by photo-oxidants. However, limitations of the current photo-oxidants, such as low biocompatibility and low affinity for A&#946;, hinder the progression of the photo-oxygenation strategy. Herein, using human serum albumins (HSA) with binding affinity for A&#946; as a platform, we have fabricated HSA-stabilized gold nanoclusters (AuNCs@HSA) and further modified the AuNCs@HSA with ethylenediamine to create basified HSA (HSA-B)-stabilized AuNCs. The basified composite, AuNCs@HSA-B, showed significantly higher potency on the inhibition of &#946;-amyloid formation and capability of reactive oxidative species generation than AuNCs@HSA. In addition to the inhibition effect, under near-infrared (NIR) laser irradiation, AuNCs@HSA-B generated singlet oxygen to oxygenate A&#946; monomers, distinctly alleviating A&#946;-mediated neurotoxicity at a low concentration. In vivo studies demonstrated that NIR-activated AuNCs@HSA-B promoted the lifespan extension of transgenic C. elegans strain CL2006 by decreasing the A&#946; burden. This well-designed AuNCs@HSA-B integrates inhibition, A&#946; targeting, and photo-oxygenation, providing new insights into the development of protein-based photo-oxidant against Alzheimer's &#946;-amyloid. STATEMENT OF SIGNIFICANCE: Alzheimer's disease (AD) has been threatening human health for more than 100 years. Recently, researchers have focused on inhibiting &#946;-amyloid protein (A&#946;) aggregation by exploring photo-excited biomaterials, which enable modulation of A&#946; fibrillization with high spatiotemporal controllability. The present work demonstrates the fabrication of basified human serum albumins (HSA-B)-stabilized gold nanoclusters (AuNCs@HSA-B), and shows the potential of this near-infrared (NIR) laser-activated AuNCs@HSA-B as a photo-oxidant against A&#946; aggregation by photo-oxygenation. Our work should open a new horizon in the design of protein-based photo-oxidant for treating AD in the future.

Liu W et al. (2020) Microb Pathog "Tea polyphenols inhibits biofilm formation, attenuates the quorum sensing-controlled virulence and enhances resistance to Klebsiella pneumoniae infection in Caenorhabditis elegans model."

Lu H, Zhang N, Chu X, Lou T, Chu W, Zhang B, Liu W

[Microb Pathog, 2020]

Bacteria cells can communicate with each other via quorum sensing (QS) system. Various physiological characteristics including virulence factors and biofilm formation are controlled by QS. So interrupting the bacterial communication is an alternative strategy instead of antibiotics for control bacterial infection. The aim of this study was to investigate the effects of tea polyphenols (TPs) on quorum sensing and virulence factors of Klebsiella pneumoniae. In vitro study showed that the anti-QS activity of tea polyphenols against Chromobacterium violaceum in violacein production. At sub-MICs, TPs inhibited the motility, reduced protease and exopolysaccharide (EPS) production and also biofilm formation in K. pneumoniae. In addition, in vivo study showed that tea polyphenols at 200g/mL and 400g/mL increased the survival rate of Caenorhabditis elegans to 73.3% and 82.2% against K. pneumonia infection. Our findings suggest that tea polyphenols can act as an effective QS inhibitor and can serve as a novel anti-virulence agent for the management of bacterial pathogens.