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Influence of Trichobilharzia regenti (Digenea: Schistosomatidae) on the defence activity of Radix lagotis (Lymnaeidae) Haemocytes.

Skála V, Černíková A, Jindrová Z, Kašný M, Vostrý M, Walker AJ, Horák P - PLoS ONE (2014)

Bottom Line: At a molecular level, protein kinase C (PKC) and extracellular-signal regulated kinase (ERK) were found to play an important role in regulating these defence reactions in R. lagotis.Moreover, haemocytes from snails with patent infection displayed lower PKC and ERK activity in cell adhesion assays when compared to those from uninfected snails, which may therefore be related to the reduced defence activities of these cells.Given that immunomodulation occurs during patency, interference of snail-host defence by T. regenti might be important for the sustained production and/or release of infective cercariae.

View Article: PubMed Central - PubMed

Affiliation: Charles University in Prague, Faculty of Science, Department of Parasitology, Prague, Czech Republic.

ABSTRACT
Radix lagotis is an intermediate snail host of the nasal bird schistosome Trichobilharzia regenti. Changes in defence responses in infected snails that might be related to host-parasite compatibility are not known. This study therefore aimed to characterize R. lagotis haemocyte defence mechanisms and determine the extent to which they are modulated by T. regenti. Histological observations of R. lagotis infected with T. regenti revealed that early phases of infection were accompanied by haemocyte accumulation around the developing larvae 2-36 h post exposure (p.e.) to the parasite. At later time points, 44-92 h p.e., no haemocytes were observed around T. regenti. Additionally, microtubular aggregates likely corresponding to phagocytosed ciliary plates of T. regenti miracidia were observed within haemocytes by use of transmission electron microscopy. When the infection was in the patent phase, haemocyte phagocytic activity and hydrogen peroxide production were significantly reduced in infected R. lagotis when compared to uninfected counterparts, whereas haemocyte abundance increased in infected snails. At a molecular level, protein kinase C (PKC) and extracellular-signal regulated kinase (ERK) were found to play an important role in regulating these defence reactions in R. lagotis. Moreover, haemocytes from snails with patent infection displayed lower PKC and ERK activity in cell adhesion assays when compared to those from uninfected snails, which may therefore be related to the reduced defence activities of these cells. These data provide the first integrated insight into the immunobiology of R. lagotis and demonstrate modulation of haemocyte-mediated responses in patent T. regenti infected snails. Given that immunomodulation occurs during patency, interference of snail-host defence by T. regenti might be important for the sustained production and/or release of infective cercariae.

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PKC and ERK phosphorylation and total ERK levels in haemocytes from uninfected and Trichobilharzia regenti infected Radix lagotis.Representative blots showing (A) PKC and (B) ERK phosphorylation in adherent haemocytes from uninfected and infected snails. (C) Levels of total ERK in uninfected and infected snails. Band intensities were measured and the mean (± SEM) haemocyte PKC and ERK phosphorylation (n = 10) and total ERK levels (n = 5) calculated (shown in the graphs) with uninfected values considered as 100%. **p<0.01 when compared to haemocyte PKC and ERK phosphorylation levels in uninfected snails; two-sample t-test.
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pone-0111696-g007: PKC and ERK phosphorylation and total ERK levels in haemocytes from uninfected and Trichobilharzia regenti infected Radix lagotis.Representative blots showing (A) PKC and (B) ERK phosphorylation in adherent haemocytes from uninfected and infected snails. (C) Levels of total ERK in uninfected and infected snails. Band intensities were measured and the mean (± SEM) haemocyte PKC and ERK phosphorylation (n = 10) and total ERK levels (n = 5) calculated (shown in the graphs) with uninfected values considered as 100%. **p<0.01 when compared to haemocyte PKC and ERK phosphorylation levels in uninfected snails; two-sample t-test.

Mentions: Because signalling pathways are known to regulate haemocyte defence responses such as phagocytosis and H2O2 output [7], [9]–[12], and because these defence responses were supressed in R. lagotis haemocytes as a result of T. regenti infection, we aimed to determine PKC and ERK activation in haemocyte monolayers derived from uninfected and infected R. lagotis. Western blotting of haemocyte proteins with anti-phosphospecific PKC and ERK antibodies, which detect only the active forms of these kinases in snails [7], [8], [27], followed by densitometric analysis of immunoreactive bands from several independent blots revealed that PKC and ERK phosphorylation were reduced by 57% and 55%, respectively, in haemocytes from infected snails when compared to those from uninfected snails (p<0.01; Figure 7A–B). We reasoned, therefore that ERK expression might also be suppressed. However, western blots performed to determine the quantity of ERK in haemocytes using antibodies that detect ERK irrespective of its phosphorylation state (Figure 7C) demonstrated that mean levels of ERK were 24% higher in infected snails when compared to uninfected ones, although this difference was not statistically significant. Unfortunately, lack of a suitable anti-PKC antibody for snails prevented evaluation of total PKC protein levels.


Influence of Trichobilharzia regenti (Digenea: Schistosomatidae) on the defence activity of Radix lagotis (Lymnaeidae) Haemocytes.

Skála V, Černíková A, Jindrová Z, Kašný M, Vostrý M, Walker AJ, Horák P - PLoS ONE (2014)

PKC and ERK phosphorylation and total ERK levels in haemocytes from uninfected and Trichobilharzia regenti infected Radix lagotis.Representative blots showing (A) PKC and (B) ERK phosphorylation in adherent haemocytes from uninfected and infected snails. (C) Levels of total ERK in uninfected and infected snails. Band intensities were measured and the mean (± SEM) haemocyte PKC and ERK phosphorylation (n = 10) and total ERK levels (n = 5) calculated (shown in the graphs) with uninfected values considered as 100%. **p<0.01 when compared to haemocyte PKC and ERK phosphorylation levels in uninfected snails; two-sample t-test.
© Copyright Policy
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC4221104&req=5

pone-0111696-g007: PKC and ERK phosphorylation and total ERK levels in haemocytes from uninfected and Trichobilharzia regenti infected Radix lagotis.Representative blots showing (A) PKC and (B) ERK phosphorylation in adherent haemocytes from uninfected and infected snails. (C) Levels of total ERK in uninfected and infected snails. Band intensities were measured and the mean (± SEM) haemocyte PKC and ERK phosphorylation (n = 10) and total ERK levels (n = 5) calculated (shown in the graphs) with uninfected values considered as 100%. **p<0.01 when compared to haemocyte PKC and ERK phosphorylation levels in uninfected snails; two-sample t-test.
Mentions: Because signalling pathways are known to regulate haemocyte defence responses such as phagocytosis and H2O2 output [7], [9]–[12], and because these defence responses were supressed in R. lagotis haemocytes as a result of T. regenti infection, we aimed to determine PKC and ERK activation in haemocyte monolayers derived from uninfected and infected R. lagotis. Western blotting of haemocyte proteins with anti-phosphospecific PKC and ERK antibodies, which detect only the active forms of these kinases in snails [7], [8], [27], followed by densitometric analysis of immunoreactive bands from several independent blots revealed that PKC and ERK phosphorylation were reduced by 57% and 55%, respectively, in haemocytes from infected snails when compared to those from uninfected snails (p<0.01; Figure 7A–B). We reasoned, therefore that ERK expression might also be suppressed. However, western blots performed to determine the quantity of ERK in haemocytes using antibodies that detect ERK irrespective of its phosphorylation state (Figure 7C) demonstrated that mean levels of ERK were 24% higher in infected snails when compared to uninfected ones, although this difference was not statistically significant. Unfortunately, lack of a suitable anti-PKC antibody for snails prevented evaluation of total PKC protein levels.

Bottom Line: At a molecular level, protein kinase C (PKC) and extracellular-signal regulated kinase (ERK) were found to play an important role in regulating these defence reactions in R. lagotis.Moreover, haemocytes from snails with patent infection displayed lower PKC and ERK activity in cell adhesion assays when compared to those from uninfected snails, which may therefore be related to the reduced defence activities of these cells.Given that immunomodulation occurs during patency, interference of snail-host defence by T. regenti might be important for the sustained production and/or release of infective cercariae.

View Article: PubMed Central - PubMed

Affiliation: Charles University in Prague, Faculty of Science, Department of Parasitology, Prague, Czech Republic.

ABSTRACT
Radix lagotis is an intermediate snail host of the nasal bird schistosome Trichobilharzia regenti. Changes in defence responses in infected snails that might be related to host-parasite compatibility are not known. This study therefore aimed to characterize R. lagotis haemocyte defence mechanisms and determine the extent to which they are modulated by T. regenti. Histological observations of R. lagotis infected with T. regenti revealed that early phases of infection were accompanied by haemocyte accumulation around the developing larvae 2-36 h post exposure (p.e.) to the parasite. At later time points, 44-92 h p.e., no haemocytes were observed around T. regenti. Additionally, microtubular aggregates likely corresponding to phagocytosed ciliary plates of T. regenti miracidia were observed within haemocytes by use of transmission electron microscopy. When the infection was in the patent phase, haemocyte phagocytic activity and hydrogen peroxide production were significantly reduced in infected R. lagotis when compared to uninfected counterparts, whereas haemocyte abundance increased in infected snails. At a molecular level, protein kinase C (PKC) and extracellular-signal regulated kinase (ERK) were found to play an important role in regulating these defence reactions in R. lagotis. Moreover, haemocytes from snails with patent infection displayed lower PKC and ERK activity in cell adhesion assays when compared to those from uninfected snails, which may therefore be related to the reduced defence activities of these cells. These data provide the first integrated insight into the immunobiology of R. lagotis and demonstrate modulation of haemocyte-mediated responses in patent T. regenti infected snails. Given that immunomodulation occurs during patency, interference of snail-host defence by T. regenti might be important for the sustained production and/or release of infective cercariae.

Show MeSH
Related in: MedlinePlus