Changes in the Expression of TLR2 During the Intestinal Phase of Trichinellosis.

INTRODUCTION: Toll-like receptors (TLRs) play an important role in fast activation of the immune response to a variety of pathogens, including parasites. In this study, we focused on TLR2, because this receptor is one of the best known and most frequently analysed members of the TLR family. The aim of this study was to assess the effect of Trichinella spiralis on expression of TLR2 during the intestinal stage of infection. MATERIAL AND METHODS: The experimental material consisted of isolates prepared from the intestines (jejunum and colon) of BALB/c mice infected with T. spiralis taken at 4, 8, and 16 days post infection. RESULTS: Our results based on quantitative real-time PCR showed that the mRNA level for TLR2 was statistically significantly higher in the jejuna of mice infected with T. spiralis than in this tissue of uninfected mice. In addition, the presence of TLR2 protein in the intestinal phase of trichinellosis was confirmed by a strong positive immunohistochemical reaction. CONCLUSION: Our results indicate that infection with T. spiralis changes the expression of TLR2 in the small intestine of the mouse host and suggest a contribution of these receptors to the host defence mechanisms during experimental trichinellosis.

The modulatory effect of Artemisia annua L. on toll-like receptor expression in Acanthamoeba infected mouse lungs.

The genus Acanthamoeba, which may cause different infections in humans, occurs widely in the environment. Lung inflammation caused by these parasites induces pulmonary pathological changes such as pulmonary necrosis, peribronchial plasma cell infiltration, moderate desquamation of alveolar cells and partial destruction of bronchial epithelial cells, and presence of numerous trophozoites and cysts among inflammatory cells. The aim of this study was to assess the influence of plant extracts from Artemisia annua L. on expression of the toll-like receptors TLR2 and TLR4 in lungs of mice with acanthamoebiasis. A. annua, which belongs to the family Asteraceae, is an annual plant that grows wild in Asia. In this study, statistically significant changes of expression of TLR2 and TLR4 were demonstrated. In the lungs of infected mice after application of extract from A. annua the expression of TLRs was observed mainly in bronchial epithelial cells, pneumocytes (to a lesser extent during the outbreak of infection), and in the course of high general TLR expression. TLR4 in particular was also visible in stromal cells of lung parenchyma. In conclusion, we confirmed that a plant extract of A. annua has a modulatory effect on components of the immune system such as TLR2 and TLR4.

Influence of Artemisia annua L. on toll-like receptor expression in brain of mice infected with Acanthamoeba sp.

The treatment of acanthamoebiasis is a still a problem. Our previous studies showed that the application of extracts from Artemisia annua L. significantly prolonged the survival of mice infected by Acanthamoeba. This plant has medicinal properties in the treatment of human parasitic diseases. The aim of this study was to evaluate the effects of A. annua on expression of Toll-like receptors (TLRs) 2 and 4 in brain of mice with Acanthamoeba infection. Mice were infected with Acanthamoeba sp. strain Ac309 (KY203908) by intranasal inoculation without and after application of A. annua extract. The administration of extract from A. annua significantly reduced the level of expression of TLR2 and modified the level of expression of TLR4. A. annua extract is a natural substance that is well tolerated in animals and may be considered as a combination therapy in treatment of acanthamoebiasis. Our study suggested that A. annua extract may be used as an alternative therapeutic tool.

Trichinella Spiralis: Impact on the Expression of Toll-like Receptor 4 (TLR4) Gene During the Intestinal Phase of Experimental Trichinellosis.

INTRODUCTION: Toll-like receptors (TLRs) play a key role in the rapid activation of the innate immune response to a variety of pathogens. The aim of this study was to evaluate the effect of Trichinella spiralis infection on the level of expression of the tlr4 gene in mouse intestines during the intestinal phase of experimental trichinellosis. MATERIAL AND METHODS: The experimental material consisted of the small and large intestines of BALB/c mice infected with Trichinella spiralis sampled at 4, 8, and 16 days post infection (dpi). RESULTS: A statistically significant increase was demonstrated in the tlr4 mRNA level isolated from the infected mice jejunum at 4, 8, and 16 dpi over the uninfected control. Moreover, at 4, 8, and 16 dpi in the jejunum of infected mice, a strong positive reaction for the presence of TLR4 protein compared with that of uninfected mice was observed. CONCLUSION: Infection with T. spiralis changes the expression of the tlr4 gene in the small intestine of the mouse host.

Toll-like receptors in the brain of mice following infection with Acanthamoeba spp.

The Toll-like receptors (TLRs) of the innate immune system play an important role in the recognition of pathogens such as bacteria, viruses, fungi, and parasites. In this study, we examined the changes in the level of expression of TLR2 and TLR4 mRNA and protein in the brains of mice infected with Acanthamoeba spp. The Acanthamoeba strains were isolated from a patient with Acanthamoeba keratitis (AK) (Ac55) and Malta Lake (Ac43). In the brain isolated from mice at 2 days post-infection (dpi) with Acanthamoeba strains Ac55 and Ac43, mRNAs for TLR2 and TLR4 were significantly more strongly expressed in comparison with the uninfected mice. In Acanthamoeba-infected mice, TLR2 and TLR4 expression was detected in neurons, glial cells, and endothelial cells within the neocortex. These receptors showed more intense expression in ependymocytes of the choroid plexus of infected mice at 2 dpi. Increased levels of TLR2 and TLR4 mRNA expression in infected mice suggest the involvement of these TLRs in the recognition of Acanthamoeba spp. pathogen-associated molecular patterns (PAMPs).

Acanthamoeba infection in lungs of mice expressed by toll-like receptors (TLR2 and TLR4).

Toll-like receptors (TLRs) play a key role in the innate immune responses to a variety of pathogens including parasites. TLRs are among the most highly conserved in the evolution of the receptor family, localized mainly on cells of the immune system and on other cells such as lung cells. The aim of this study was to determine for the first time the expression of TLR2 and TLR4 in the lung of Acanthamoeba spp. infected mice using quantitative real-time polymerase chain reaction (Q-PCR) and immunohistochemical (IHC) staining. The Acanthamoeba spp. were isolated from a patient with Acanthamoeba keratitis (AK) (strain Ac 55) and from environmental samples of water from Malta Lake (Poznan, Poland - strain Ac 43). We observed a significantly increased level of expression of TLR2 as well as TLR4 mRNA from 2 to 30 days post Acanthamoeba infection (dpi) in the lungs of mice infected with Ac55 (KP120880) and Ac43 (KP120879) strains. According to our observations, increased TLR2 and TLR4 expression in the pneumocytes, interstitial cells and epithelial cells of the bronchial tree may suggest an important role of these receptors in protective immunity against Acanthamoeba infection in the lung. Moreover, increased levels of TLR2 and TLR4 mRNA expression in infected Acanthamoeba mice may suggest the involvement of these TLRs in the recognition of this amoeba pathogen-associated molecular pattern (PAMP).

Hymenolepis diminuta: analysis of the expression of Toll-like receptor genes and protein (TLR3 and TLR9) in the small and large intestines of rats.

Toll-like receptors (TLRs) play a fundamental role in the rapid activation of innate immune responses to a variety of pathogen-associated molecular patterns (PAMPs). In a previous study we observed an increase in the level of expression of TLR2 and TLR4 mRNA in the jejunum and colon during experimental hymenolepidosis in rats. In this study, we performed a quantitative real-time polymerase chain reaction (qRT-PCR), Western blot analysis and immunohistochemical staining of TLR3 and TLR9 receptors during experimental hymenolepidosis in rats. The levels of mRNA and protein expression of TLR3 and TLR9 in the jejunum had increased at 16 days post Hymenolepis diminuta infection (dpi) in the case of TLR3 and at 16 and 25 dpi in the case of TLR9. In the colon the expression of TLR3 and TLR9 had increased at 16, 25 and 40 dpi. The results of the immunohistochemical reactions showed that H. diminuta infected rats (16, 25, 40 and 60 dpi) exhibited changes in TLR3 and TLR9 localization and intensity in the epithelial cells of the jejunum and colon. The changes in the level of TLR3 and TLR9 expression may confirm involvement of the innate immune system in the pathomechanism of hymenolepidosis.

Trichinellosis in mice: effect of albendazole on the glutathione transferase in the intestines.

The glutathione S-transferases (GSTs) are a family of multifunctional enzymes involved in cellular detoxification. The aim of this study was to evaluate the effect of albendazole--drug of choice for trichinellosis--on the total activity and kinetics of cytosolic GST in the mouse intestines during experimental trichinellosis. Our results showed a statistically significant decrease in the total GST activity both in the small and large intestines of the mice infected with the nematode Trichinella spiralis (Owen, 1835) and treated with albendazole, compared with the control mice that were infected but untreated with the drug. Furthermore, albendazole administration modified the kinetics of substrate saturation of GST in the intestines of the infected mice because the drug caused changes in Michaelis constant values of this enzyme. Based on our observations, we suggest that the quaternary structure of GST from the mouse intestines is impacted by this drug during trichinellosis.

Changes in the activity and kinetics of mouse intestinal glutathione transferase during experimental trichinellosis.

The glutathione S-transferases (GSTs) are a group of multifunctional enzymes, which play a critical role in cellular detoxification. Our investigations deal with the contribution of GST in the biochemical defense against Trichinella spiralis infection. The aim of this study was to examine the effect of T. spiralis infection on the total activity and kinetic properties of cytosolic GST in the intestine during the intestinal phase of experimental trichinellosis in mice. Our results showed a statistically significant increase (relative to the uninfected control) in the total GST activity both in the small and large intestines of the infected mice. Moreover, we observed changes in the kinetics of substrate saturation of GST. Trichinellosis in the small intestine caused a 12-fold decrease in the low K (m) value and a sixfold increase in the high K (m) value. In the large intestine, infection with T. spiralis caused only a fivefold increase in the low K (m) value, whereas the high K (m) value remained unchanged. We suggest that GST from the mouse small intestine could be involved in the detoxification of parasite excretory-secretory products released to the host intestine during trichinellosis and that these products influence the quaternary structure of this enzyme.

[Effect in vitro of albendazole on the kinetics of cytosolic glutathione transferase from the rat liver]. / Badania in vitro wplywu albendazolu na kinetyke reakcji ka- talizowanej przez cytozolowa transferaze glutationowa (GST) z watroby szczura.

INTRODUCTION: Since the idea of multifunctional mode of action of anthelmintics is considered and in experimental trichinellosis in vivo albendazole seems to act as an allosteric activator of cytosolic GST from mice muscles, in this study a termosensitivity after in vitro incubation with albendazole of purified commercial cytosolic glutathione transferase (GST) from the rat liver was investigated. METHODS: Two extremal temperatures: -80 degrees C and +30 degrees C were used to destroy the dimer in quaternary structure of this enzyme. RESULTS: In control preparations both extremal temperatures destroy this structure, so the Michaelis-Menten kinetic curves of substrate saturation show the typical hyperbolic shape. After a long (15 h) freezing at -80 degrees C or heating (up to 14 h at +30 degrees C) the kinetics of substrate saturation of GST after incubation with albendazole show the sigmoidal or "double sigmoidal" shape, pointing out the quaternary GST structure as a complex of "frozen subunits". Drug inhibits about 6-times the total activity of GST after incubation at +30 degrees C. We conclude that albendazole in vitro influences the structure of cytosolic GST from the rat liver and inhibits its activity, but, in opposite to in vivo study in mouse muscles infected with Trichinella spiralis larvae, does not act as an activator of this enzyme.

Evaluation of effects of albendazole on the kinetics of cytosolic glutathione transferase in skeletal muscles during experimental trichinellosis in mice.

In this study, the effect of trichinellosis as well as the effect of albendazole treatment on the kinetics of substrate saturation of cytosolic glutathione transferase (GST) in the skeletal muscles from infected mice was examined because the idea of multifunctional mode of action of anthelmintic drugs was considered. Our results pointed out to the influence of trichinellosis and albendazole treatment on the quaternary structure of GST in mouse muscles. A double reciprocal plot of GST saturation in control mice was biphasic with apparent low and high K (m) values equal to 0.54 and 1.0 mM, respectively. Infection with Trichinella spiralis in the third week postinfection caused a 2.3-fold increase in the high K (m) value and at the same time a 2.8-fold decrease in the low K (m). In the sixth week postinfection, the high K (m) value was unchanged, but the low K (m) value increased 2.3 times. Calculated from the double reciprocal plot of GST substrate saturation in muscles from infected and treated mice (measured in the third week postinfection only), the high K (m) value increased 1.4 times relative to the respective controls. The normal substrate saturation plot of GST in treated mice has a clearly "double sigmoid" character. Our results suggest that despite the complicated character of the GST saturation curve, albendazole seems to act as an allosteric activator for cytosolic GST in infected mouse muscles.

Effect of aminoguanidine and albendazole on inducible nitric oxide synthase (iNOS) activity in T. spiralis-infected mice muscles.

The aim of this study was to provide evidence for the expression of iNOS in the cells of inflammatory infiltrates around larvae in skeletal muscles of T. spiralis infected mice. The BALB/c mice (n = 8) divided into subgroups, received either aminoguanidine (AMG)--a specific iNOS inhibitor or albendazole (ALB)--an antiparasitic drug of choice in trichinellosis treatment. Control animals (n = 2 in each subgroup) were either uninfected and treated or uninfected and untreated. Frozen sections of hind leg muscles from mice sacrificed at various time intervals after infection were cut and subjected to immunohistochemistry, using monoclonal anti-iNOS antibody. The ALB-treated mice revealed stronger iNOS staining in the infiltrating cells around larvae than the infected and untreated animals. On the contrary, in the AMG-treated animals, the infiltrating cells did not show any specific iNOS reaction. These data confirm the specificity of iNOS staining in the cellular infiltrates around T. spiralis larvae and shed some light on the role of nitric oxide during ALB treatment in experimental trichinellosis.

Changes in the level of antioxidants in the blood from mice infected with Trichinella spiralis.

The biological reaction caused by oxygen-derived free radicals at the molecular and cellular levels involves many different biochemical components which can be directly damaged by oxidizing radicals. As such a reaction may lead to pathological processes, defence mechanisms have evolved to limit the rate of free radical production. These mechanisms employ low-molecular-weight non-enzymatic antioxidants and antioxidant enzymes which are inducible by oxidant stress. In this study, the activity of two antioxidant enzymes, superoxide dismutase (EC 1.15.1.1) and glutathione peroxidase (EC 1.11.1.9), and the level of non-enzymatic antioxidants (total antioxidant status) in the blood from mice infected with Trichinella spiralis was examined. We observed a statistically significant, up to above twofold increase (relative to the control value in uninfected mice) in the level of both enzymes as well as in the total antioxidant status. An intensification of antioxidant processes during trichinellosis could be related to the presence of T. spiralis larvae, which may induce phagocytes to generate free radicals. Our research shows that the maximum growth in antioxidant activity in the blood appears during the period of the greatest muscle damage caused by T. spiralis infection at 3-7 weeks post-infection.

mRNA expression and immunohistochemical localization of inducible nitric oxide synthase (NOS-2) in the muscular niche of Trichinella spiralis.

The aim of this study was to demonstrate iNOS mRNA expression in muscular phase of experimental trichinellosis and to localize iNOS protein in T. spiralis-infected muscles using specific anti-iNOS monoclonal antibodies. The expression of iNOS mRNA in skeletal muscles from Trichinella spiralis-infected mice was examined using the reverse transcription PCR assay. Fragments of skeletal muscles were also subjected to the immunohistochemical reaction using specific anti-iNOS monoclonal antibodies followed by Dako-Ark test. mRNA for iNOS measured on day 21 after infection was expressed in the muscular phase of trichinellosis. Positive immunostaining for iNOS occurred in infiltrating mononuclear cells around the encapsulated larvae. iNOS-positive cells could be traced from the 21st day post infection (dpi); on 42 dpi and 90 dpi most cells expressed iNOS. By assessing expression of protein and its mRNA it can be concluded that iNOS is active in the pathology of skeletal muscle tissue in experimental trichinellosis.

[The intriguing influence of albendazole on glutathione reductase activity in the muscles from Trichinella spiralis infected mice]. / Intrygujacy wplyw albendazolu na aktywnosc reduktazy glutationu w miesniach myszy zarazonych Trichinella spiralis.

A clear stimulation of the activity of glutathione reductase (RG, EC 1.6.4.2), one of the major enzymes participating in glutathione metabolism, was observed in the skeletal muscles from Trichinella spiralis infected mice. The maximal, almost two-fold increase in RG activity was observed in week 5 post-infection. Administration of albendazole, an anthelmintic widely used in trichinellosis treatment, resulted in an additional, about 40% stimulation of RG activity (small, but statistically significant) on week 2 post-infection. In weeks 6 and 7 post-infection, when no stimulation of RG activity in infected mice caused by drug was observed, the drug modified the structure of that allosteric enzyme, affecting the kinetics of its substrate saturation in this way that the shape of the substrate saturation curve changed from "double sigmoidal", typical of this enzyme kinetics in the muscles from infected mice, to hyperbolic, typical of this enzyme kinetics in the control, uninfected animals.

[The role of nitric oxide (NO) in parasitic infections]. / Rola tlenku azotu w inwazjach pasozytniczych.

Nitric oxide (NO) has been shown to play a crucial role in various physiological and pathological conditions. NO plays a role in the immunoregulation and it is implicated in the host non-specific defence in a variety of infections. Abundant evidence indicates that NO contributes to the host defence function of macrophages. High levels of NO are mediated by up-regulated expression of the iNOS gene in response to the activating signals, in particular to the secretion of pro-inflammatory cytokines (IFN-gamma, TNF-alpha, IL-1, IL-2) by Thl cells. In this review, the role of NO during a number of parasitic infections has been summarized. Up to now, enhanced levels of NO production and expression of iNOS gene have been described in such infective diseases as malaria, toxoplasmosis, leishmaniosis, trypanosomosis and schistosomosis. During these infections, the preferential production of pro-inflammatory cytokines predisposes to the increased synthesis of NO, which mediates host protection through either direct parasite killing or by limiting parasite growth. The evidence presented in this review supports the conclusion that NO plays an important role in the majority of parasitic infections.

Effect of nitric oxide releasing drugs on the intensity of infection during experimental trichinellosis in mice.

Nitric oxide (NO) has been shown to play a critical role in various physiological and pathological conditions. Apart from its physiological functions, NO indirectly participates in certain aspects of the pathology of infectious diseases. The aim of this work was to examine the influence of NO-releasing drugs on the intensity of infection in mice infected with Trichinella spiralis. The selected substances were nitroglycerin, isosorbide dinitrate, nitrendipine, sildenafil, and pentaerythritol. These were administered over a prolonged period of time: from the 3rd to the 28th day post-infection. Our study showed that NO administered during trichinellosis may enhance the infection in mice as compared to untreated controls. Thus, treatment with pentaerythritol caused a 44% increase in the intensity of infection relative to the untreated controls, sildenafil a 37% increase, and nitrendipine a 30% increase. This effect may be related to the action of NO on the host's defence mechanisms.

Changes in the activity of glutathione-S-transferase in muscles and sera from mice infected with Trichinella spiralis after treatment with albendazole and levamisole.

In this study, changes in GST activity before and after treatment with antiparasitic drugs were measured in muscles and sera from mice infected with Trichinella spiralis between the 2nd and 9th weeks post-infection (wpi). Levamisole and albendazole, two anthelmintics with a different mode of action, were used. An about twofold stimulation of GST activity in the 2nd wpi and in the later muscular phase (6-7 wpi) was observed in muscles from animals treated with albendazole. In addition, a statistically significant stimulation of GST activity was observed after levamisole treatment, however, only from the 2nd()to the 4th wpi. Neither drugs changed the GST activity in serum. These results suggest that both anthelmintics seem to increase the total activity of GST participating in oxygen free radical-based biochemical defence against Trichinella infection.

Release of nitric oxide during experimental trichinellosis in mice.

Nitric oxide (NO) is one of the secretory products of macrophages. Abundant evidence indicates that NO contributes to the host defence functions of these cells. The aim of this study was to test the hypothesis that the induced form of NO synthase (iNOS) may participate in the defence of the host against Trichinella. To investigate whether NO was produced during trichinellosis, we examined NO serum levels as an indicator of NO production by iNOS in mice infected with T. spiralis. A statistically significant increase in the NO serum levels relative to the control group (uninfected animals) was observed during weeks 2-8 post-infection. This increase suggest that iNOS is induced during experimental trichinellosis in mice. In the next stage of our study, we compared the NO synthesis by peritoneal macrophages isolated from infected mice with those from uninfected control. A statistically significant increase in the NO release from macrophages obtained from infected mice was noticed on days 7, 21, 29, 43 and 63 post-infection. These results suggest that infection with T. spiralis induces NO production by macrophages.

Effect of exogenous nitric oxide in experimental trichinellosis.

Nitric oxide (NO) is a free radical that has been given much attention over the past few years. It has been nicknamed a "killer" and "mediator" due to its toxic and signaling properties. Apart from its regular physiological function, NO indirectly participates in infectious diseases. Our investigations showed that NO administered as a drug may involve higher histopathological changes in infected animals and can involve higher infection. This report seems to be the first presentation of the participation of NO reactive nitrogen intermediates in the morphological transformation of muscle cells in trichinellosis.