Wen H et al. (2014) Integr Biol (Camb) "Probing the anti-aging role of polydatin in Caenorhabditis elegans on a chip."

Wen H, Qin J, Gao X

[Integr Biol (Camb), 2014]

C. elegans is widely used as a model organism in the study of aging and evaluation of anti-aging drugs due to its unique characteristics. In this work, we set out to investigate polydatin, a natural resveratrol glycoside, and its role in extending lifespan, improving oxidative stress resistance, and the possible regulation mechanism involved in the Insulin/IGF-1 signaling (IIS) pathway for the first time by using a flexible microfluidic device. The effects of polydatin on the lifespan, oxidative stress resistance, mobility and the expression of aging-related proteins and genes were explored. Polydatin was found to significantly extend the mean lifespan of worms by up to 30.7% and 62.1% under normal and acute stress conditions respectively. It improved the expression of the inducible oxidative stress protein (GST-4) and corresponding stroke frequencies in the transgenic CL2166 strain. Moreover, it also increased SOD-3::GFP expression in CF1553 worms and promoted DAF-16 nucleus translocation in TJ356 worms. The longevity-extending role of polydatin is partly attributed to its anti-oxidative activity and increased oxidative stress resistance by regulating the stress-resistance related proteins SOD-3, and daf-16 expression at protein and mRNA levels involved in the IIS pathway. The established microfluidic platform is capable of flexible operation with multiple functions, which not only supports the individual worm's long-term culture with sufficient nutrient exchange, but also facilitates mobility monitoring of the worm, immobilizing and imaging in a controllable and parallel manner. These interesting findings reported here highlight the significance of the natural compound polydatin in the study of aging-related diseases, and the utility of the microfluidic platform for applications in aging studies.

Wen H et al. (2015) Lab Chip "A droplet microchip with substance exchange capability for the developmental study of C. elegans."

Wen H, Yu Y, Qin J, Zhu G, Jiang L

[Lab Chip, 2015]

The nematode Caenorhabditis elegans (C. elegans) has been widely used as a multicellular organism in developmental research due to its simplicity, short lifecycle, and its relevance to human genetics and biology. Droplet microfluidics is an attractive platform for the study of C. elegans in integrated mode with flexibility at the single animal resolution. However, it is still challenging to conduct the developmental study of worms within droplets initiating at the L1 larval stage, due to the small size, active movement, and the difficulty in achieving effective substance exchange within the droplets. Here, we present a multifunctional droplet microchip to address these issues and demonstrate the usefulness of this device for investigating post-embryonic development in individual C. elegans initiating at the larval L1 stage. The key components of this device consist of multiple functional units that enable parallel worm loading, droplet formation/trapping, and worm encapsulation in parallel. In particular, it exhibits superior functions in encapsulating and trapping individual larval L1 worms into droplets in a controlled way. Continuous food addition and expulsion of waste by mixing the static worm-in-droplet with moving medium plugs allows for the long-term culture of worms under a variety of conditions. We used this device to investigate the development processes of C. elegans in transgenic strains with deletion and overexpression of the hypoxia-inducible factor (HIF-1), a highly conserved transcript factor in regulating an organism's response to hypoxia. This microdevice may be a useful tool for the high throughput analysis of individual worms starting at the larval stage, and facilitates the study of developmental worms in response to multiple drugs or environmental toxins.

Wen H et al. (2012) Biomed Microdevices "Multiparameter evaluation of the longevity in C. elegans under stress using an integrated microfluidic device."

Shi W, Wen H, Qin J

[Biomed Microdevices, 2012]

Caenorhabditis elegans (C. elegans) is an excellent model organism for the study of aging and longevity. In this work, we presented a microfluidic approach for the evaluation of longevity in C. elegans under stress. The microfluidic device integrated multiple microvalves with parallel channels, which enabled the long-term culture and flexible manipulation of C. elegans in real-time. The utility of the device was demonstrated by characterizing the lifespan, mobility behavior and fluorescence expression of oxidative stress in mutant strain CL2166 simultaneously at single animal resolution. A certain dose of polydatin was found to enable the extension of mean lifespan of CL2166 for the first time, and the prolonged longevity activity was possibly mediated by the protective response to oxidative stress, indicating the promising role of polydatin involved in aging process. The device is simple to operate, easy for real-time imaging and multiparatemer evaluations in parallel, providing the powerful platform for drug evaluation/screening in highthroughput format.

Wen C-h et al. (1999) J Cell Biol "p24 proteins and quality control of LIN-12 and GLP-1 trafficking in Caenorhabditis elegans."

Greenwald IS, Wen C-h

[J Cell Biol, 1999]

Mutations in the Caenorhabditis elegans sel-9 gene elevate the activity of lin-12 and glp-1, which encode members of the LIN-12/NOTCH family of receptors. Sequence analysis indicates SEL-9 is one of several C. elegans p24 proteins. Allele-specific genetic interactions suggest that reducing sel-9 activity increases the activity of mutations altering the extracellular domains of LIN-12 or GLP-1. Reducing sel-9 activity restores the trafficking to the plasma membrane of a mutant GLP-1 protein that would otherwise accumulate within the cell. Our results suggest a role for SEL-9 and other p24 proteins in the negative regulation of transport of LIN-12 and GLP-1 to the cell surface, and favor a role for p24 proteins in a quality control mechanism for endoplasmic reticulum-Golgi transport.

Wen C-h et al. (2000) Proc Natl Acad Sci U S A "spr-2, a suppressor of the egg-laying defect caused by loss of sel-12 presenilin in Caenorhabditis elegans, is a member of the SET protein subfamily."

Wen C-h, Greenwald IS, Levitan DJ, Li XJ

[Proc Natl Acad Sci U S A, 2000]

Presenilin plays critical roles in the genesis of Alzheimer's disease and in LIN-12/Notch signaling during development. Here, we describe a screen for genes that influence presenilin level or activity in Caenorhabditis elegans. We identified four spr (suppressor of presenilin) genes by reverting the egg-laying defective phenotype caused by a null allele of the sel-12 presenilin gene. We analyzed the spr-2 gene in some detail. We show that loss of spr-2 activity suppresses the egg-laying defective phenotype of different sel-12 alleles and requires activity of the hop-1 presenilin gene, suggesting that suppression is accomplished by elevating presenilin activity rather than by bypassing the need for presenilin activity. We also show that SPR-2 is a nuclear protein and is a member of a protein subfamily that includes human SET, which has been identified in numerous different biochemical assays and at translocation breakpoints associated with a subtype of acute myeloid leukemia.

Sun J et al. (2013) Exp Parasitol "Parasitism of secondary-stage juvenile of Heterodera glycines and four larva stages of Caenorhabditis elegans by Hirsutella spp."

Sun J, Xie H, Xiang M, Liu X, Qiu J

[Exp Parasitol, 2013]

The fungi Hirsutella rhossiliensis and Hirsutella minnesotensis generally parasitize only plant-parasitic nematodes in nature but parasitize the bacterivorous nematode Caenorhabditis elegans on agar plates. To establish a model system for studying the interaction between fungi and nematodes, we compared the parasitism of the first- to fourth-stage larvae (L1-L4) of C. elegans and second-stage juvenile (J2) of Heterodera glycines by twenty isolates of Hirsutella spp. Although parasitism differed substantially among isolates, both H. minnesotensis and H. rhossiliensis parasitized a higher percentage of H. glycines J2s than of C. elegans larvae. Parasitism of C. elegans L1s was correlated with parasitism of H. glycines J2s. Parasitism of C. elegans by H. rhossiliensis and H. minnesotensis was negatively correlated with larva size and motility, i.e., parasitism was higher for the younger stages. The C. elegans L1 is recommended for studying parasitism of nematodes by H. rhossiliensis and H. minnesotensis.

Fei YJ et al. (2000) J Biol Chem "A novel H(+)-coupled oligopeptide transporter (OPT3) from Caenorhabditis elegans with a predominant function as a H(+) channel and an exclusive expression in neurons."

Leibach FH, Romero MF, Krause MW, Huang W, Ganapathy V, Fei YJ, Liu JC

[J Biol Chem, 2000]

We have cloned and functionally characterized a novel, neuron-specific, H(+)-coupled oligopeptide transporter (OPT3) from Caenorhabditis elegans that functions predominantly as a H(+) channel. The opt3 gene is approximately 4.4 kilobases long and consists of 13 exons. The cDNA codes for a protein of 701 amino acids with 11 putative transmembrane domains. When expressed in mammalian cells and in Xenopus laevis oocytes, OPT3 cDNA induces H(+)-coupled transport of the dipeptide glycylsarcosine. Electrophysiological studies of the transport function of OPT3 in Xenopus oocytes show that this transporter, although capable of mediating H(+)-coupled peptide transport, functions predominantly as a H(+) channel. The H(+) channel activity of OPT3 is approximately 3-4-fold greater than the H(+)/peptide cotransport activity as determined by measurements of H(+) gradient-induced inward currents in the absence and presence of the dipeptide using the two-microelectrode voltage clamp technique. A downhill influx of H(+) was accompanied by a large intracellular acidification as evidenced from the changes in intracellular pH using an ion-selective microelectrode. The H(+) channel activity exhibits a K(0.5)(H) of 1.0 microM at a membrane potential of -50 mV. At the level of primary structure, OPT3 has moderate homology with OPT1 and OPT2, two other H(+)-coupled oligopeptide transporters previously cloned from C. elegans. Expression studies using the opt3::gfp fusion constructs in transgenic C. elegans demonstrate that opt3 gene is exclusively expressed in neurons. OPT3 may play an important physiological role as a pH balancer in the maintenance of H(+) homeostasis in C. elegans.

Wilson PA et al. (1982) Parasitology "Strongyloides ratti (homogonic): the time-course of early migration in the generalized host deduced from experiments in lactating rats."

Steven GE, Simpson NE, Wilson PA

[Parasitology, 1982]

Unsuckled mother rats given a 1 h suckling stimulus 3 h after subcutaneous injection of an exact dose of homogonic Strongyloides ratti allow fewer worms to develop in their intestines by day 9 than nulliparous rats (Wilson & Simpson, 1981). This effect is studied in more detail in terms of the length of time between weaning and stimulus (W leads to S) and injection and stimulus (I leads to S). It was observable with a W leads to S of 30 h but this and a period of 5 h were less effective than 24 h. With W leads to S constant at 24 h, significantly more worms developed in mothers when I leads to S was 24 h compared to 3 h and 10 h (P less than 0.005). The data, combined with those from nulliparous controls, are presented as a measure of the change with time of numbers of larvae in that compartment of the system which gives access to the stimulated mammary gland. It is argued that the particular compartment is the local lymph node draining the injection site and that the kinetics deduced are applicable to migration in the rat in general.

Miller DL et al. (2007) Proc Natl Acad Sci U S A "Hydrogen sulfide increases thermotolerance and lifespan in Caenorhabditis elegans."

Miller DL, Roth MB

[Proc Natl Acad Sci U S A, 2007]

Hydrogen sulfide (H(2)S) is naturally produced in animal cells. Exogenous H(2)S has been shown to effect physiological changes that improve the capacity of mammals to survive in otherwise lethal conditions. However, the mechanisms required for such alterations are unknown. We investigated the physiological response of Caenorhabditis elegans to H(2)S to elucidate the molecular mechanisms of H(2)S action. Here we show that nematodes exposed to H(2)S are apparently healthy and do not exhibit phenotypes consistent with metabolic inhibition. Instead, animals exposed to H(2)S are thermotolerant and long-lived. These phenotypes require SIR-2.1 activity but are genetically independent of the insulin signaling pathway, mitochondrial dysfunction, and caloric restriction. These studies suggest that SIR-2.1 activity may translate environmental change into physiological alterations that improve survival. It is interesting to consider the possibility that the mechanisms by which H(2)S increases thermotolerance and lifespan in nematodes are conserved and that studies using C. elegans may help explain the beneficial effects observed in mammals exposed to H(2)S.

Rosas PC et al. (2016) PLoS One "Hsp72 (HSPA1A) Prevents Human Islet Amyloid Polypeptide Aggregation and Toxicity: A New Approach for Type 2 Diabetes Treatment."

Kaur P, Rosas PC, Wickman G, Panossian A, Al-Khamis FA, Nagaraja GM, Garcia LR, Asea AA

[PLoS One, 2016]

Type 2 diabetes is a growing public health concern and accounts for approximately 90% of all the cases of diabetes. Besides insulin resistance, type 2 diabetes is characterized by a deficit in -cell mass as a result of misfolded human islet amyloid polypeptide (h-IAPP) which forms toxic aggregates that destroy pancreatic -cells. Heat shock proteins (HSP) play an important role in combating the unwanted self-association of unfolded proteins. We hypothesized that Hsp72 (HSPA1A) prevents h-IAPP aggregation and toxicity. In this study, we demonstrated that thermal stress significantly up-regulates the intracellular expression of Hsp72, and prevents h-IAPP toxicity against pancreatic -cells. Moreover, Hsp72 (HSPA1A) overexpression in pancreatic -cells ameliorates h-IAPP toxicity. To test the hypothesis that Hsp72 (HSPA1A) prevents aggregation and fibril formation, we established a novel C. elegans model that expresses the highly amyloidogenic human pro-IAPP (h-proIAPP) that is implicated in amyloid formation and -cell toxicity. We demonstrated that h-proIAPP expression in body-wall muscles, pharynx and neurons adversely affects C. elegans development. In addition, we demonstrated that h-proIAPP forms insoluble aggregates and that the co-expression of h-Hsp72 in our h-proIAPP C. elegans model, increases h-proIAPP solubility. Furthermore, treatment of transgenic h-proIAPP C. elegans with ADAPT-232, known to induce the expression and release of Hsp72 (HSPA1A), significantly improved the growth retardation phenotype of transgenic worms. Taken together, this study identifies Hsp72 (HSPA1A) as a potential treatment to prevent -cell mass decline in type 2 diabetic patients and establishes for the first time a novel in vivo model that can be used to select compounds that attenuate h-proIAPP aggregation and toxicity.