IL-4 up-regulates cyclooxygenase-1 expression in macrophages.

Macrophages use various cell-surface receptors to sense their environment and undergo polarized responses. The cytokines, interleukin (IL)-4 and IL-13, released from T-helper type 2 (Th2) cells, drive macrophage polarization toward an alternatively activated phenotype (M2). This phenotype is associated with the expression of potent pro-resolving mediators, such as the prostaglandin (PG) D2-derived cyclopentenone metabolite, 15d-PGJ2, produced by the cyclooxygenase (Ptgs; Cox) pathway. Interestingly, IL-4 treatment of bone marrow-derived macrophages (BMDMs) significantly down-regulates Cox-2 protein expression, whereas Cox-1 levels are significantly increased. This phenomenon not only challenges the dogma that Cox-1 is only developmentally regulated, but also demonstrates a novel mechanism in which IL-4-dependent regulation of Cox-1 involves the activation of the mechanistic target of rapamycin complex (mTORC). Using specific chemical inhibitors, we demonstrate here that IL-4-dependent Cox-1 up-regulation occurs at the post-transcriptional level via the Fes-Akt-mTORC axis. Activation of AMP-activated protein kinase (AMPK) by metformin, inhibition of mTORC by torin 1, or CRISPR/Cas9-mediated genetic knock-out of tuberous sclerosis complex-2 (Tsc2) blocked the IL-4-dependent expression of Cox-1 and the ability of macrophages to polarize to M2. However, use of 15d-PGJ2 partially rescued the effects of AMPK activation, suggesting the importance of Cox-1 in macrophage polarization as also observed in a model of gastrointestinal helminth clearance. In summary, these findings suggest a new paradigm where IL-4-dependent up-regulation of Cox-1 expression may play a key role in tissue homeostasis and wound healing during Th2-mediated immune responses, such as parasitic infections.

Unusual terpenylated acylphloroglucinols from Dryopteris wallichiana.

Four unusual terpenylated acylphloroglucinols were isolated from the diethyl ether extract of the scales and rhizomes of the fern Dryopteris wallichiana together with the known compounds albaspidins AA and AB, and filixic acids ABA and ABB. Structures of the isolated compounds were established by extensive spectroscopic analysis and their absolute configuration at C-14″ was determined by comparing their CD spectra with those simulated for the respective isomers. Pure acylphloroglucinols displayed moderate in vitro nematocidal activity against L4 stage larvae of Nippostrongylus brasiliensis (LD50=22-121 µM).

Synthesis and biological evaluation of simplified mycothiazole analogues.

Thiazoline and oxazoline analogues of the natural product mycothiazole were synthesized from a common intermediate and evaluated in vitro against HCT-15 colon cancer cells and L(4) larvae of nematode Nippostrongylus brasiliensis. The nature of the heterocyclic moiety seems to modulate the cytotoxic or anthelmintic activity.

[Activity of the anthelmintic agent trichlorophen on the models of human helminthiasis]. / Aktivnost' otechestvennogo antigel'mintika trikhlofena na modeliakh gel'mintozov cheloveka.

Trials of trichlorophen have shown its high efficacy on models of cestode infections: hymenolepiasis (at the adult and cysticercoid stages of development on three types of animals: outbred albino mice, albino rats and golden hamsters), preimaginal echinococciasis alveolaris, larval alveolar echinococciasis (at the early stage of development of the parasite in experiments on cotton rats). The high nematodical activity of trichlorophen was first found on models of trichocephaliasis in DBA/2y mice, nippostrongyloidiasis (in in vitro experiments), and aspiculuriasis in outbred mice. The agent proved to be ineffective at the tissue developmental stage of Hymenolepsis nana (H. nana), the dwarf tapeworm, in albino mice, during experimental opisthorchiasis in golden hamsters. It showed a low efficacy in treating trichinosis in outbred albino mice. Unlike carbamatebenzimidazoles, trichlorophen was inactive at the tissue stage of H. nana; it exerted no effects on the eggs of a dwarf tapeworm in trichinosis. Trichlorophen was also inactive in treating experimental opisthorchiasis in golden hamsters.

Resistance of cotton rats, Sigmodon hispidus, to primary infection by Nippostrongylus brasiliensis.

The resistance of cotton rats, Sigmodon hispidus to Nippostrongylus brasiliensis infection was examined and compared the response to that of the susceptible Indian soft-furred rat, Millardia meltada. After a primary infection with infective third-stage N. brasiliensis larvae (L3), the number of eggs in feces and adult worm recovery rates from the small intestine of cotton rats were significantly lower than in the controls. To determine whether cotton rat resistance was observed during the migratory phase or the intestinal phase, cotton rats and control animals were challenged subcutaneously with L3 or intraduodenally with adult worms, and larval recovery from lungs and adult worm burden were evaluated. The recovery rate of larvae from the lungs of cotton rats was about five-fold lower than from controls. Adult worm recovery from the small intestine of cotton rats was also lower than that from the controls, but the difference (two-fold lower) was smaller than that observed for lung recovery. Carbon treatment at a dose of 250-500 mg/kg effectively increased larval worm recovery from the lungs of cotton rats. However, this treatment had no effect on worm recovery from the intestine after intraduodenal implantation of adult N. brasiliensis. These results suggest that macrophage function have important role in the expression of strong resistance during the migratory phase of N. brasiliensis infection in cotton rats.

Nematocidal activity of natural polyphenols from bryophytes and their derivatives.

The nematocidal in vitro activity of three natural perotetins (phenolic bisbibenzyiethers) and eleven diphenyl ethers used as synthetic precursors has been assayed using two different experimental models, Caenorhabditis elegans and Nippostrongylus brasiliensis. Nine compounds showed some activity against C. elegans and nine against N. brasiliensis. For the former model, three compounds displayed an activity similar to that of the standards, whereas for N. brasiliensis none of the tested compounds was as active as the standards. From the in vitro results, five compounds (3, 4, 8, 9, 13) could be selected as lead compounds to continue the search for improved activity.

External stimuli and intracellular signalling in the modification of the nematode surface during transition to the mammalian host environment.

Previous work has shown that the surface of infective larvae of parasitic nematodes will not bind the fluorescent lipid analogue 5-N-(octadecanoyl)aminofluorescein (AF18) until after exposure of the parasite to mammalian tissue-culture conditions. In this study, culture media which are permissive or non-permissive for the acquisition of lipophilicity for AF18 were altered in order to examine possible stimuli involved. This showed that external alkaline pH and high sodium ion concentration were highly stimulatory. The internal signalling pathways which may be involved in the surface alteration were then examined using agents which are known to affect intracellular signalling in mammalian cells. The results indicated that elevation of cGMP levels was stimulatory whereas inhibition of a putative Na+/H+ antiporter or calcium mobilization was inhibitory, and it is argued that high intracellular levels of cAMP may be inhibitory. Whilst the precise effects of the agents used on nematode cells remain to be established, these results provide a framework for the examination of the processes involved in the modification of the nematode surface which takes place immediately after the infection event.

Efficacy of methyl 5(6)-(alpha-hydroxyphenylmethyl) benzimidazole-2-carbamate, a metabolite of mebendazole, against developing forms of experimental helminth parasites.

Methyl 5(6)-(alpha-hydroxyphenylmethyl) benzimidazole-2- carbamate, a metabolite of mebendazole, was evaluated against metamorphic forms of Ancylostoma ceylanicum in hamsters, Nippostrongylus brasiliensis in rats and cysticercoids of Hymenolepis nana in grain beetles. The test compound offered better action than mebendazole except against H. nana cysticercoids where the activity of the compound and mebendazole was comparable, but was inferior to the standard cestodicidal drug, praziquantel. The results suggest that the action was better by ip route compared to per os route of drug administration.

Synthesis of 2,5-disubstituted benzimidazoles, 1,3,4-thiadiazoles and 3,5-diiodosalicylanilides as structural congeners of rafoxanide and closantel.

The synthesis of a series of 2,5-disubstituted benzimidazoles (8-10, 13), substituted 3,5-diodosalicylanilides (6, 7, 11, 12, 16-29), 2-(4-substituted phenyl)-4-aroylamino-1,3,4-thiadiazoles (33-38) and benzoxazines (14, 30, 31) has been carried out as the structural congeners of rafoxanide and closantel. All the compounds have been tested for their anthelmintic activity against Ancylostoma ceylanicum, Nippostrongylus brasiliensis, Hymenolepis nana and Cysticecus fasciolaris in rodents. Compounds 8, 22 and 23 exhibited 90-100% elimination of the hookworms A. ceylanicum and tapeworms H. nana from hamsters and rats, respectively, at an oral dose 50-250 mg/kg body mass.

Efficacy of a substituted methyl benzimidazole carbamate against developing and adult helminth parasites.

The efficacy of a substituted methyl benzimidazole carbamate, methyl 5(6)-[4-N-(2-pyridyl)] piperazino carbamoyl benzimidazole-2-carbamate, was assessed against larval and adult forms of Ancylostoma ceylanicum (hookworm), Nippostrongylus brasiliensis (trichostrongylid), Hymenolepis nana (tapeworm) and Brugia malayi (filariid) in experimentally-infected animals. The compound was found to have high efficacy against the developing stages (L3, L4, L5) of A. ceylanicum in hamsters at a single dose of 12.5 mg kg-1, against larvae of N. brasiliensis at 17.5 mg kg-1 and against cysticercoids of Hymenolepis nana at 100 mg kg-1 daily for 3 days given per os (p.o.) or intraperitoneally (i.p.). All the stages of B. malayi in Mastomys were killed when the compound was given i.p. at a dose of 6.25 mg kg-1 for 5 consecutive days. A dose of 6.25 mg kg-1 eliminated all adult A. ceylanicum from infected hamsters, 100 mg kg-1 resulted in complete removal of Syphacia obvelata adults from 63.6% of infected mice, 25 mg kg-1 X 5 dose eliminated 100% of adult B. malayi from infected Mastomys and a single 50 mg kg-1 dose expelled all H. nana adults from infected rats.