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Targeting mosquito FREP1 with a fungal metabolite blocks malaria transmission.

Niu G, Wang B, Zhang G, King JB, Cichewicz RH, Li J - Sci Rep (2015)

Bottom Line: The inhibition specificity was confirmed by immunofluorescence assays.Therefore, disruption of the interaction between FREP1 and parasites effectively reduces Plasmodium infection in mosquitoes.Targeting FREP1 with small molecules is thus an effective novel approach to block malaria transmission.

View Article: PubMed Central - PubMed

Affiliation: Department of Chemistry and Biochemistry, University of Oklahoma, 101 Stephenson Parkway, Norman, OK 73019, USA.

ABSTRACT
Inhibiting Plasmodium development in mosquitoes will block malaria transmission. Fibrinogen-related protein 1 (FREP1) is critical for parasite infection in Anopheles gambiae and facilitates Plasmodium invasion in mosquitoes through interacting with gametocytes and ookinetes. To test the hypothesis that small molecules that disrupt this interaction will prevent parasites from infecting mosquitoes, we developed an ELISA-based method to screen a fungal extract library. We obtained a candidate fungal extract of Aspergillus niger that inhibited the interaction between FREP1 and P. falciparum infected cells by about 92%. The inhibition specificity was confirmed by immunofluorescence assays. Notably, feeding mosquitoes with the candidate fungal extract significantly inhibited P. falciparum infection in the midgut without cytotoxicity or inhibition of the development of P. falciparum gametocytes or ookinetes. A bioactive natural product that prevents FREP1 from binding to gametocytes or ookinetes was isolated and identified as P-orlandin. Importantly, the nontoxic orlandin significantly reduced P. falciparum infection intensity in mosquitoes. Therefore, disruption of the interaction between FREP1 and parasites effectively reduces Plasmodium infection in mosquitoes. Targeting FREP1 with small molecules is thus an effective novel approach to block malaria transmission.

No MeSH data available.


Related in: MedlinePlus

Chapel SA-3 extract is not toxic to cells and it does not affect mosquito lifespan.(a) The extract from isolate Chapel SA-3 did not lyse human blood at the concentration of 100 μg/mL or lower. (b) The extract from isolate Chapel SA-3 did not show apparent cytotoxicity to the mosquito cell line. Sua5B at the concentration of 100 μg/mL or lower. (c) There was no difference among the lifespan of adult mosquitoes that were fed with human blood, and human blood supplemented with 1% DMSO or 100 μg/mL Chapel SA-3 extract.
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f4: Chapel SA-3 extract is not toxic to cells and it does not affect mosquito lifespan.(a) The extract from isolate Chapel SA-3 did not lyse human blood at the concentration of 100 μg/mL or lower. (b) The extract from isolate Chapel SA-3 did not show apparent cytotoxicity to the mosquito cell line. Sua5B at the concentration of 100 μg/mL or lower. (c) There was no difference among the lifespan of adult mosquitoes that were fed with human blood, and human blood supplemented with 1% DMSO or 100 μg/mL Chapel SA-3 extract.

Mentions: First, we analyzed the hemolysis activity of Chapel SA-3. Incubating different concentrations of Chapel SA-3 with 10% human RBC in PBS revealed that Chapel SA-3 did not cause detectable lysis of RBC at the concentration of 100 μg/mL or lower (Fig. 4a). Even at a high concentration of 500 μg/mL, Chapel SA-3 lysed much fewer RBC than the positive control (Saponin treated). Next, we tested the cytotoxicity of Chapel SA-3 on mosquito cells. A serial concentration of Chapel SA-3 was added into Sua5B cell culture medium. Two days later, alive and dead cells were counted. Results show no significant difference (p = 0.2) for Sua5B cells treated with Chapel SA-3 at a concentration of 100 μg/mL or lower (Fig. 4b), indicating that Chapel SA-3 is nontoxic to mosquito cells. Furthermore, we determined the effects of Chapel SA-3 on the lifespan of mosquitoes. Mosquitoes were fed with human blood or human blood supplemented with 1% DMSO or 100 μg/mL Chapel SA-3, and the numbers of surviving mosquitoes were counted every day. Our results showed that Chapel SA-3 did not kill mosquitoes immediately, and did not affect the mosquito lifespan (Fig. 4c). Collectively, Chapel SA-3 effectively prevented P. falciparum from infecting An. gambiae mosquitoes without introducing potential stress to mosquitoes, which will not exert any selective pressure on mosquito populations.


Targeting mosquito FREP1 with a fungal metabolite blocks malaria transmission.

Niu G, Wang B, Zhang G, King JB, Cichewicz RH, Li J - Sci Rep (2015)

Chapel SA-3 extract is not toxic to cells and it does not affect mosquito lifespan.(a) The extract from isolate Chapel SA-3 did not lyse human blood at the concentration of 100 μg/mL or lower. (b) The extract from isolate Chapel SA-3 did not show apparent cytotoxicity to the mosquito cell line. Sua5B at the concentration of 100 μg/mL or lower. (c) There was no difference among the lifespan of adult mosquitoes that were fed with human blood, and human blood supplemented with 1% DMSO or 100 μg/mL Chapel SA-3 extract.
© Copyright Policy - open-access
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC4593950&req=5

f4: Chapel SA-3 extract is not toxic to cells and it does not affect mosquito lifespan.(a) The extract from isolate Chapel SA-3 did not lyse human blood at the concentration of 100 μg/mL or lower. (b) The extract from isolate Chapel SA-3 did not show apparent cytotoxicity to the mosquito cell line. Sua5B at the concentration of 100 μg/mL or lower. (c) There was no difference among the lifespan of adult mosquitoes that were fed with human blood, and human blood supplemented with 1% DMSO or 100 μg/mL Chapel SA-3 extract.
Mentions: First, we analyzed the hemolysis activity of Chapel SA-3. Incubating different concentrations of Chapel SA-3 with 10% human RBC in PBS revealed that Chapel SA-3 did not cause detectable lysis of RBC at the concentration of 100 μg/mL or lower (Fig. 4a). Even at a high concentration of 500 μg/mL, Chapel SA-3 lysed much fewer RBC than the positive control (Saponin treated). Next, we tested the cytotoxicity of Chapel SA-3 on mosquito cells. A serial concentration of Chapel SA-3 was added into Sua5B cell culture medium. Two days later, alive and dead cells were counted. Results show no significant difference (p = 0.2) for Sua5B cells treated with Chapel SA-3 at a concentration of 100 μg/mL or lower (Fig. 4b), indicating that Chapel SA-3 is nontoxic to mosquito cells. Furthermore, we determined the effects of Chapel SA-3 on the lifespan of mosquitoes. Mosquitoes were fed with human blood or human blood supplemented with 1% DMSO or 100 μg/mL Chapel SA-3, and the numbers of surviving mosquitoes were counted every day. Our results showed that Chapel SA-3 did not kill mosquitoes immediately, and did not affect the mosquito lifespan (Fig. 4c). Collectively, Chapel SA-3 effectively prevented P. falciparum from infecting An. gambiae mosquitoes without introducing potential stress to mosquitoes, which will not exert any selective pressure on mosquito populations.

Bottom Line: The inhibition specificity was confirmed by immunofluorescence assays.Therefore, disruption of the interaction between FREP1 and parasites effectively reduces Plasmodium infection in mosquitoes.Targeting FREP1 with small molecules is thus an effective novel approach to block malaria transmission.

View Article: PubMed Central - PubMed

Affiliation: Department of Chemistry and Biochemistry, University of Oklahoma, 101 Stephenson Parkway, Norman, OK 73019, USA.

ABSTRACT
Inhibiting Plasmodium development in mosquitoes will block malaria transmission. Fibrinogen-related protein 1 (FREP1) is critical for parasite infection in Anopheles gambiae and facilitates Plasmodium invasion in mosquitoes through interacting with gametocytes and ookinetes. To test the hypothesis that small molecules that disrupt this interaction will prevent parasites from infecting mosquitoes, we developed an ELISA-based method to screen a fungal extract library. We obtained a candidate fungal extract of Aspergillus niger that inhibited the interaction between FREP1 and P. falciparum infected cells by about 92%. The inhibition specificity was confirmed by immunofluorescence assays. Notably, feeding mosquitoes with the candidate fungal extract significantly inhibited P. falciparum infection in the midgut without cytotoxicity or inhibition of the development of P. falciparum gametocytes or ookinetes. A bioactive natural product that prevents FREP1 from binding to gametocytes or ookinetes was isolated and identified as P-orlandin. Importantly, the nontoxic orlandin significantly reduced P. falciparum infection intensity in mosquitoes. Therefore, disruption of the interaction between FREP1 and parasites effectively reduces Plasmodium infection in mosquitoes. Targeting FREP1 with small molecules is thus an effective novel approach to block malaria transmission.

No MeSH data available.


Related in: MedlinePlus