Whole-cell patch-clamp recording of nicotinic acetylcholine receptors in adult Brugia malayi muscle

Robertson, Alan P.; Buxton, Samuel; Martin, R. J.

doi:10.1016/j.parint.2013.03.008

Cited by 21 publications

(33 citation statements)

References 18 publications

(18 reference statements)

Supporting

Mentioning

Contrasting

Order By: Relevance

“…The results presented here are similar to those reported for adult female B. malayi, where 30 lM levamisole inhibited motility by 85 % in 10 min, but the worms recovered within an hour (Robertson et al 2013). Possible reasons for the transient paralysis seen in 1 mM levamisole might be that this concentration of drug causes the nAChRs at the neuromuscular junction to be downregulated or otherwise desensitized (Taly et al 2009).…”

supporting

confidence: 87%

“…It and other nicotinic agonists are widely used as anthelmintic drugs against gastrointestinal parasites of livestock, but have not been widely used against filarial parasites which inhabit tissues other than the GI tract. Recently, it has been shown that adult Brugia malayi, the causative agent of about 10 % of cases of lymphatic filariasis, possesses levamisole-sensitive nAChRs (Robertson et al 2011(Robertson et al , 2013. We therefore undertook to study the effect of the drug on the locomotion of microfilariae (Mf).…”

mentioning

confidence: 99%

See 1 more Smart Citation

Transient effects of levamisole on Brugia malayi microfilariae

Mostafa

Storey²,

Farghaly

et al. 2015

Invert Neurosci

View full text Add to dashboard Cite

Levamisole is an anthelmintic drug that acts by activating nicotinic acetylcholine receptors at the nematode neuromuscular junction and causing paralysis. We measured the in vitro effects of levamisole on the motility of Brugia malayi microfilariae; after 2 h incubation the apparent IC50 was 2.68 mM. Lower drug concentrations, such as 1 mM, caused an immediate total paralysis that lasted for up to 1 h, but was completely reversed by 2 h of incubation. The 'recovered' parasites were still completely susceptible to application of a second nicotinic agonist, pyrantel.

show abstract

supporting

confidence: 87%

mentioning

confidence: 99%

Transient effects of levamisole on Brugia malayi microfilariae

Mostafa

Storey²,

Farghaly

et al. 2015

Invert Neurosci

View full text Add to dashboard Cite

show abstract

“…In Ascaris suum, there are three separable muscle subtypes [N-, L-, and B- (27)] and four types in Oesophagostomum dentatum (11). Xenopus expression experiments suggest in Haemonchus contortus and Oesophagostomum dentatum that: the L-type (L-AChR-1) is composed of UNC-63, UNC-38, UNC-29, and ACR-8 subunits; the P-type (L-AChR-2) is composed of UNC-63, UNC-38, and UNC-29 subunits (10,25); and the N-type in Ascaris suum is composed of ACR-16 subunits (14,35,50). A fourth type of muscle nAChR selectively activated by morantel and composed of ACR-26 and ACR-27 subunits has been described in Haemonchus contortus (51).…”

Section: Discussionmentioning

confidence: 99%

“…Their neuromuscular systems are unlike those of vertebrates because nematode muscles send processes to the motor neurons to form synapses, rather than the other way around. Membrane ion-channels, which regulate nematode neuromuscular systems, are target sites of major classes of anthelmintic drugs, including the cholinergic anthelmintics levamisole, pyrantel, and derquantel (10)(11)(12)(13)(14)(15)(16)(17). Here, we have combined a number of techniques for the study of muscle pentameric acetylcholine receptor channels (nAChRs) of the filarial nematode parasite, Brugia malayi.…”

mentioning

confidence: 99%

“…To study the functional genomics of nAChRs of B. malayi, we used the following: (i) video capture for quantitative phenotyping (23,24); (ii) single-cell PCR to identify nAChR subunit genes expressed in muscle (25); (iii) dsRNA for RNAi knockdown of unc-38+unc-29 of nematode levamisole and pyrantel receptors (26,27), and (iv) whole-cell patch clamp to record functional properties of muscle nAChRs (10,28). Knockdown of acr-16+acr-26 had little effect on motility, but knockdown of unc-38+unc-29 abolished motility, suggesting in B. malayi that different physiological functions may be ascribed to different receptors.…”

mentioning

confidence: 99%

See 1 more Smart Citation

Functional genomics in Brugia malayi reveal diverse muscle nAChRs and differences between cholinergic anthelmintics

Verma

Kashyap

Robertson

et al. 2017

Proc. Natl. Acad. Sci. U.S.A.

View full text Add to dashboard Cite

Many techniques for studying functional genomics of important target sites of anthelmintics have been restricted to Caenorhabditis elegans because they have failed when applied to animal parasites. To overcome these limitations, we have focused our research on the human nematode parasite Brugia malayi, which causes elephantiasis. Here, we combine single-cell PCR, whole muscle cell patch clamp, motility phenotyping (Worminator), and dsRNA for RNAi for functional genomic studies that have revealed, in vivo, four different muscle nAChRs (M-, L-, P-, and N-). The cholinergic anthelmintics had different selectivities for these receptors. We show that motility and patch-clamp responses to levamisole and pyrantel, but not morantel or nicotine, require the unc-38 and/or unc-29 genes. Derquantel behaved as a competitive antagonist and distinguished M-nAChRs activated by morantel (K b 13.9 nM), P-nAChRs activated by pyrantel (K b 126 nM), and L-nAChRs activated by levamisole (K b 0.96 μM) and bephenium. Derquantel was a noncompetitive antagonist of nicotine, revealing N-type nAChRs. The presence of four diverse nAChRs on muscle is perhaps surprising and not predicted from the C. elegans model. The diverse nAChRs represent distinguishable drug targets with different functions: Knockdown of unc-38+unc-29 (L-and/or P-receptors) inhibited motility but knockdown of acr-16+acr-26 (M-and/or N-receptors) did not.T he neglected tropical diseases caused by nematode parasites affect some 2 billion people globally, and effective vaccines are not available. Although these parasites by themselves do not produce high mortality, they produce significant morbidity that affects worker productivity and increase susceptibility to AIDS and malaria, and they are strongly associated with poverty in endemic countries (1-4). There are only a limited number of classes of anthelmintic drugs that are used to treat these diseases, and there are concerns about the development of resistance (5). There is a pressing need to advance the study of anthelmintic drugs.Many useful studies on modes of action of anthelmintic drugs have been conducted on the model nematode, Caenorhabditis elegans, but this is not a parasite: It is separated evolutionarily by millions of years from parasitic nematodes and it does not possess "parasitism genes" (6). This separation increases the impetus for anthelmintic studies using real parasites, but until now many techniques developed in C. elegans have not have been tractable when applied to animal parasites (7).The neuromuscular systems of nematodes, which control motility and support feeding, growth, and reproduction, are governed by significant parts of their gene pools (8, 9). Their neuromuscular systems are unlike those of vertebrates because nematode muscles send processes to the motor neurons to form synapses, rather than the other way around. Membrane ion-channels, which regulate nematode neuromuscular systems, are target sites of major classes of anthelmintic drugs, including the cholinergic anthelmintics levamisole,...

show abstract

Ivermectin inhibits extracellular vesicle secretion from parasitic nematodes

Loghry

Wang

Zamanian

et al. 2020

J of Extracellular Vesicle

View full text Add to dashboard Cite

Lymphatic filariasis (LF) is a disease caused by parasitic filarial nematodes that is endemic in 49 countries of the world and affects or threatens over 890 million people. Strategies to control LF rely heavily on mass administration of anthelmintic drugs including ivermectin (IVM), a macrocyclic lactone drug considered an Essential Medicine by the WHO. However, despite its widespread use the therapeutic mode of action of IVM against filarial nematodes is not clear. We have previously reported that filarial nematodes secrete extracellular vesicles (EVs) and that their cargo has immunomodulatory properties. Here we investigate the effects of IVM and other anti‐filarial drugs on parasitic nematode EV secretion, motility, and protein secretion. We show that inhibition of EV secretion was a specific property of IVM, which had consistent and significant inhibitory effects across nematode life stages and species, with the exception of male parasites. IVM inhibited EV secretion, but not parasite motility, at therapeutically relevant concentrations. Protein secretion was inhibited by IVM in the microfilariae stage, but not in any other stage tested. Our data provides evidence that inhibiting the secretion of immunomodulatory EVs by parasitic nematodes could explain, at least in part, IVM mode of action and provides a phenotype for novel drug discovery.

show abstract

Whole-cell patch-clamp recording of nicotinic acetylcholine receptors in adult Brugia malayi muscle

Cited by 21 publications

References 18 publications

Transient effects of levamisole on Brugia malayi microfilariae

Transient effects of levamisole on Brugia malayi microfilariae

Functional genomics in Brugia malayi reveal diverse muscle nAChRs and differences between cholinergic anthelmintics

Ivermectin inhibits extracellular vesicle secretion from parasitic nematodes

Contact Info

Product

Resources

About