Limits...
Anti-malarial activity of geldanamycin derivatives in mice infected with Plasmodium yoelii.

Mout R, Xu ZD, Wolf AK, Jo Davisson V, Jarori GK - Malar. J. (2012)

Bottom Line: Treatment with GA derivatives blocked the transition from ring to trophozoite stage presumably by the inhibition of HSP90 associated functions.Persistence of parasite in ring stage leads to robust humoral immune response as well as a shift in invasion specificity from normocytes to reticulocyte.It is likely that the treatment with the water-soluble GA derivative creates an attenuated state (less virulent with altered invasion specificity) that persists in the host system, allowing it to mount a robust immune response.

View Article: PubMed Central - HTML - PubMed

Affiliation: Department of Biological Sciences, Tata Institute of Fundamental Research, Mumbai, India.

ABSTRACT

Background: Geldanamycin (GA), a benzoquinone ansamycin antibiotic has been shown in vitro to possess anti-plasmodial activity. Pharmacological activity of this drug is attributed to its ability to inhibit PfHSP90. The parasite growth arrest has been shown to be due to drug-induced blockage of the transition from ring to trophozoite stage. To further evaluate the consequences of this pharmacodynamic feature, the anti-malarial activity of GA analogs with enhanced drug properties in a Plasmodium-infected animal model have been evaluated for their capacity to induce clearance of the parasite. In the process, a hypothesis was subsequently tested regarding the susceptibility of the cured animals to malaria reflected in an attenuated parasite load that may be evoked by a protective immune response in the host.

Methods: Six weeks old Swiss mice were infected with a lethal Plasmodium yoelii (17XL) strain. On appearance of clinical symptoms of malaria, these animals were treated with two different GA derivatives and the parasite load was monitored over 15-16 days. Drug-treated animals cured of the parasite were then re-challenged with a lethal dose of P. yoelii 17XL. Serum samples from GA cured mice that were re-challenged with P. yoelii 17XL were examined for the presence of antibodies against the parasite proteins using western blot analysis.

Results: Treatment of P. yoelii 17XL infected mice with GA derivatives showed slow recovery from clinical symptoms of the disease. Blood smears from drug treated mice indicated a dominance of ring stage parasites when compared to controls. Although, P. yoelii preferentially invades normocytes (mature rbcs), in drug-treated animals there was an increased invasion of reticulocytes. Cured animals exhibited robust protection against subsequent infection and serum samples from these animals showed antibodies against a vast majority of parasite proteins.

Conclusions: Treatment with GA derivatives blocked the transition from ring to trophozoite stage presumably by the inhibition of HSP90 associated functions. Persistence of parasite in ring stage leads to robust humoral immune response as well as a shift in invasion specificity from normocytes to reticulocyte. It is likely that the treatment with the water-soluble GA derivative creates an attenuated state (less virulent with altered invasion specificity) that persists in the host system, allowing it to mount a robust immune response.

Show MeSH

Related in: MedlinePlus

Serum samples from geldanamycin treated mice have antibodies against vast majority of parasite proteins. Protein extracts from (A) P. yoelii and (B) mouse rbcs were analyzed on 12% SDS-PAGE. Gels were either silver stained (lanes 1, 6, 8 & 10) or blotted on PVDF membrane and probed with various serum samples collected from mice. (A) P. yoelii cell extract: silver stained (lane 1); Western using naïve mice serum (lane 2); malaria sensitive mouse serum (lane 3); serum from GA treated mice (lane 4) and serum from chloroquine treated mice (lane 5). (B) Mouse RBC extract: un-infected (lanes 6 & 7), ~3% parasitemia (lanes 8 & 9) and ~30% parasitemia (lanes 10 & 11). Lanes 6, 8 & 10 are silver stained while lanes 7, 9 & 11 are western blots developed using pooled sera from GA treated mice.
© Copyright Policy - open-access
Related In: Results  -  Collection

License
getmorefigures.php?uid=PMC3361485&req=5

Figure 6: Serum samples from geldanamycin treated mice have antibodies against vast majority of parasite proteins. Protein extracts from (A) P. yoelii and (B) mouse rbcs were analyzed on 12% SDS-PAGE. Gels were either silver stained (lanes 1, 6, 8 & 10) or blotted on PVDF membrane and probed with various serum samples collected from mice. (A) P. yoelii cell extract: silver stained (lane 1); Western using naïve mice serum (lane 2); malaria sensitive mouse serum (lane 3); serum from GA treated mice (lane 4) and serum from chloroquine treated mice (lane 5). (B) Mouse RBC extract: un-infected (lanes 6 & 7), ~3% parasitemia (lanes 8 & 9) and ~30% parasitemia (lanes 10 & 11). Lanes 6, 8 & 10 are silver stained while lanes 7, 9 & 11 are western blots developed using pooled sera from GA treated mice.

Mentions: To examine the antibody profiles of serum samples collected from above mentioned three groups of mice, proteins from the whole cell parasite extracts were separated using a 12% SDS-PAGE and transferred to a PVDF membrane. These blots were subjected to western analysis using different serum samples. Results of such western analysis are shown in Figure 6. Lane 1 is a silver stained protein profile of the whole cell P. yoelii extract. Western blots made using the sera collected from naïve (lane 2) and parasite sensitive mice sera (lane 3) did not show any reactivity towards the parasite proteins. In contrast to these, serum samples collected from 17-AAG or 17-PEG-Alkyn-GA treated mice had antibodies against vast majority of parasite proteins (lane 4). Sera collected from the chloroquine treated group showed antibodies against a subset of the parasite proteins (lane 5). These data are consistent with a hypothesis that drug-induced antibody response mounted by the host against the drug-attenuated parasite leads to protection against a subsequent parasite challenge.


Anti-malarial activity of geldanamycin derivatives in mice infected with Plasmodium yoelii.

Mout R, Xu ZD, Wolf AK, Jo Davisson V, Jarori GK - Malar. J. (2012)

Serum samples from geldanamycin treated mice have antibodies against vast majority of parasite proteins. Protein extracts from (A) P. yoelii and (B) mouse rbcs were analyzed on 12% SDS-PAGE. Gels were either silver stained (lanes 1, 6, 8 & 10) or blotted on PVDF membrane and probed with various serum samples collected from mice. (A) P. yoelii cell extract: silver stained (lane 1); Western using naïve mice serum (lane 2); malaria sensitive mouse serum (lane 3); serum from GA treated mice (lane 4) and serum from chloroquine treated mice (lane 5). (B) Mouse RBC extract: un-infected (lanes 6 & 7), ~3% parasitemia (lanes 8 & 9) and ~30% parasitemia (lanes 10 & 11). Lanes 6, 8 & 10 are silver stained while lanes 7, 9 & 11 are western blots developed using pooled sera from GA treated mice.
© Copyright Policy - open-access
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC3361485&req=5

Figure 6: Serum samples from geldanamycin treated mice have antibodies against vast majority of parasite proteins. Protein extracts from (A) P. yoelii and (B) mouse rbcs were analyzed on 12% SDS-PAGE. Gels were either silver stained (lanes 1, 6, 8 & 10) or blotted on PVDF membrane and probed with various serum samples collected from mice. (A) P. yoelii cell extract: silver stained (lane 1); Western using naïve mice serum (lane 2); malaria sensitive mouse serum (lane 3); serum from GA treated mice (lane 4) and serum from chloroquine treated mice (lane 5). (B) Mouse RBC extract: un-infected (lanes 6 & 7), ~3% parasitemia (lanes 8 & 9) and ~30% parasitemia (lanes 10 & 11). Lanes 6, 8 & 10 are silver stained while lanes 7, 9 & 11 are western blots developed using pooled sera from GA treated mice.
Mentions: To examine the antibody profiles of serum samples collected from above mentioned three groups of mice, proteins from the whole cell parasite extracts were separated using a 12% SDS-PAGE and transferred to a PVDF membrane. These blots were subjected to western analysis using different serum samples. Results of such western analysis are shown in Figure 6. Lane 1 is a silver stained protein profile of the whole cell P. yoelii extract. Western blots made using the sera collected from naïve (lane 2) and parasite sensitive mice sera (lane 3) did not show any reactivity towards the parasite proteins. In contrast to these, serum samples collected from 17-AAG or 17-PEG-Alkyn-GA treated mice had antibodies against vast majority of parasite proteins (lane 4). Sera collected from the chloroquine treated group showed antibodies against a subset of the parasite proteins (lane 5). These data are consistent with a hypothesis that drug-induced antibody response mounted by the host against the drug-attenuated parasite leads to protection against a subsequent parasite challenge.

Bottom Line: Treatment with GA derivatives blocked the transition from ring to trophozoite stage presumably by the inhibition of HSP90 associated functions.Persistence of parasite in ring stage leads to robust humoral immune response as well as a shift in invasion specificity from normocytes to reticulocyte.It is likely that the treatment with the water-soluble GA derivative creates an attenuated state (less virulent with altered invasion specificity) that persists in the host system, allowing it to mount a robust immune response.

View Article: PubMed Central - HTML - PubMed

Affiliation: Department of Biological Sciences, Tata Institute of Fundamental Research, Mumbai, India.

ABSTRACT

Background: Geldanamycin (GA), a benzoquinone ansamycin antibiotic has been shown in vitro to possess anti-plasmodial activity. Pharmacological activity of this drug is attributed to its ability to inhibit PfHSP90. The parasite growth arrest has been shown to be due to drug-induced blockage of the transition from ring to trophozoite stage. To further evaluate the consequences of this pharmacodynamic feature, the anti-malarial activity of GA analogs with enhanced drug properties in a Plasmodium-infected animal model have been evaluated for their capacity to induce clearance of the parasite. In the process, a hypothesis was subsequently tested regarding the susceptibility of the cured animals to malaria reflected in an attenuated parasite load that may be evoked by a protective immune response in the host.

Methods: Six weeks old Swiss mice were infected with a lethal Plasmodium yoelii (17XL) strain. On appearance of clinical symptoms of malaria, these animals were treated with two different GA derivatives and the parasite load was monitored over 15-16 days. Drug-treated animals cured of the parasite were then re-challenged with a lethal dose of P. yoelii 17XL. Serum samples from GA cured mice that were re-challenged with P. yoelii 17XL were examined for the presence of antibodies against the parasite proteins using western blot analysis.

Results: Treatment of P. yoelii 17XL infected mice with GA derivatives showed slow recovery from clinical symptoms of the disease. Blood smears from drug treated mice indicated a dominance of ring stage parasites when compared to controls. Although, P. yoelii preferentially invades normocytes (mature rbcs), in drug-treated animals there was an increased invasion of reticulocytes. Cured animals exhibited robust protection against subsequent infection and serum samples from these animals showed antibodies against a vast majority of parasite proteins.

Conclusions: Treatment with GA derivatives blocked the transition from ring to trophozoite stage presumably by the inhibition of HSP90 associated functions. Persistence of parasite in ring stage leads to robust humoral immune response as well as a shift in invasion specificity from normocytes to reticulocyte. It is likely that the treatment with the water-soluble GA derivative creates an attenuated state (less virulent with altered invasion specificity) that persists in the host system, allowing it to mount a robust immune response.

Show MeSH
Related in: MedlinePlus