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Concurrent transcriptional profiling of Dirofilaria immitis and its Wolbachia endosymbiont throughout the nematode life cycle reveals coordinated gene expression.

Luck AN, Evans CC, Riggs MD, Foster JM, Moorhead AR, Slatko BE, Michalski ML - BMC Genomics (2014)

Bottom Line: Interestingly, a large proportion of both D. immitis and wDi genes display microfilarial-biased transcriptional patterns.Concurrent transcriptome sequencing identified potential molecular interactions between parasite and endosymbiont that are more prominent during certain life cycle stages.In support of metabolite provisioning between filarial nematodes and Wolbachia, the synthesis of the critical metabolite, heme, by wDi appears to be synchronized in a stage-specific manner (mf-specific) with the production of heme-binding proteins in D. immitis.

View Article: PubMed Central - PubMed

Affiliation: Department of Biology and Microbiology, University of Wisconsin Oshkosh, Oshkosh, WI 54901, USA. michalsk@uwosh.edu.

ABSTRACT

Background: Dirofilaria immitis, or canine heartworm, is a filarial nematode parasite that infects dogs and other mammals worldwide. Current disease control relies on regular administration of anthelmintic preventives, however, relatively poor compliance and evidence of developing drug resistance could warrant alternative measures against D. immitis and related human filarial infections be taken. As with many other filarial nematodes, D. immitis contains Wolbachia, an obligate bacterial endosymbiont thought to be involved in providing certain critical metabolites to the nematode. Correlations between nematode and Wolbachia transcriptomes during development have not been examined. Therefore, we detailed the developmental transcriptome of both D. immitis and its Wolbachia (wDi) in order to gain a better understanding of parasite-endosymbiont interactions throughout the nematode life cycle.

Results: Over 215 million single-end 50 bp reads were generated from total RNA from D. immitis adult males and females, microfilariae (mf) and third and fourth-stage larvae (L3 and L4). We critically evaluated the transcriptomes of the various life cycle stages to reveal sex-biased transcriptional patterns, as well as transcriptional differences between larval stages that may be involved in larval maturation. Hierarchical clustering revealed both D. immitis and wDi transcriptional activity in the L3 stage is clearly distinct from other life cycle stages. Interestingly, a large proportion of both D. immitis and wDi genes display microfilarial-biased transcriptional patterns. Concurrent transcriptome sequencing identified potential molecular interactions between parasite and endosymbiont that are more prominent during certain life cycle stages. In support of metabolite provisioning between filarial nematodes and Wolbachia, the synthesis of the critical metabolite, heme, by wDi appears to be synchronized in a stage-specific manner (mf-specific) with the production of heme-binding proteins in D. immitis.

Conclusions: Our integrated transcriptomic study has highlighted interesting correlations between Wolbachia and D. immitis transcription throughout the life cycle and provided a resource that may be used for the development of novel intervention strategies, not only for the treatment and prevention of D. immitis infections, but of other closely related human parasites as well.

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Expression profiles ofWolbachiametabolic pathways and genes of interest throughout theD.immitislife cycle. Heatmap showing the expression (normalized FPKM values) of genes involved in the synthesis of heme, riboflavin, purines, pyrimidines, folate, peptidoglycan/lipid II, isoprenoid, as well as components of the Sec translocase and the type IV secretion system. Each gene is represented by a single row. Data from biological replicates were combined prior to clustering. The color scale ranges from white (no expression) to black (very high expression).
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Fig4: Expression profiles ofWolbachiametabolic pathways and genes of interest throughout theD.immitislife cycle. Heatmap showing the expression (normalized FPKM values) of genes involved in the synthesis of heme, riboflavin, purines, pyrimidines, folate, peptidoglycan/lipid II, isoprenoid, as well as components of the Sec translocase and the type IV secretion system. Each gene is represented by a single row. Data from biological replicates were combined prior to clustering. The color scale ranges from white (no expression) to black (very high expression).

Mentions: While the host-symbiont relationship between filarial nematodes and Wolbachia cannot be reduced to one process or factor, a number of obvious relationships can be inferred based on genetic profiling of the two organisms [12, 73, 74]. D. immitis lacks specific genes required for de novo synthesis of purines, pyrimidines and other cofactors (heme and riboflavin). Similar to Wolbachia from B. malayi (wBm) [12] these pathways are complete within the wDi genome [19]. Conversely, biosynthetic pathways of other vitamins and cofactors such as Coenzyme A, NAD, biotin, lipoic acid, ubiquinone and pyridoxal phosphate are incomplete in wDi and thus, may be supplied to the endosymbiont by the host. Although previous transcriptomic studies found little evidence of metabolite provisioning between Wolbachia and O. ochengi[33], we focused our analysis on transcription of these specific wDi pathways (Figure 4, Additional file 13: Table S9), which may provide further information on the evolutionary biology of Wolbachia and highlight opportunities for further drug targeting and development.Figure 4


Concurrent transcriptional profiling of Dirofilaria immitis and its Wolbachia endosymbiont throughout the nematode life cycle reveals coordinated gene expression.

Luck AN, Evans CC, Riggs MD, Foster JM, Moorhead AR, Slatko BE, Michalski ML - BMC Genomics (2014)

Expression profiles ofWolbachiametabolic pathways and genes of interest throughout theD.immitislife cycle. Heatmap showing the expression (normalized FPKM values) of genes involved in the synthesis of heme, riboflavin, purines, pyrimidines, folate, peptidoglycan/lipid II, isoprenoid, as well as components of the Sec translocase and the type IV secretion system. Each gene is represented by a single row. Data from biological replicates were combined prior to clustering. The color scale ranges from white (no expression) to black (very high expression).
© Copyright Policy - open-access
Related In: Results  -  Collection

License 1 - License 2
Show All Figures
getmorefigures.php?uid=PMC4289336&req=5

Fig4: Expression profiles ofWolbachiametabolic pathways and genes of interest throughout theD.immitislife cycle. Heatmap showing the expression (normalized FPKM values) of genes involved in the synthesis of heme, riboflavin, purines, pyrimidines, folate, peptidoglycan/lipid II, isoprenoid, as well as components of the Sec translocase and the type IV secretion system. Each gene is represented by a single row. Data from biological replicates were combined prior to clustering. The color scale ranges from white (no expression) to black (very high expression).
Mentions: While the host-symbiont relationship between filarial nematodes and Wolbachia cannot be reduced to one process or factor, a number of obvious relationships can be inferred based on genetic profiling of the two organisms [12, 73, 74]. D. immitis lacks specific genes required for de novo synthesis of purines, pyrimidines and other cofactors (heme and riboflavin). Similar to Wolbachia from B. malayi (wBm) [12] these pathways are complete within the wDi genome [19]. Conversely, biosynthetic pathways of other vitamins and cofactors such as Coenzyme A, NAD, biotin, lipoic acid, ubiquinone and pyridoxal phosphate are incomplete in wDi and thus, may be supplied to the endosymbiont by the host. Although previous transcriptomic studies found little evidence of metabolite provisioning between Wolbachia and O. ochengi[33], we focused our analysis on transcription of these specific wDi pathways (Figure 4, Additional file 13: Table S9), which may provide further information on the evolutionary biology of Wolbachia and highlight opportunities for further drug targeting and development.Figure 4

Bottom Line: Interestingly, a large proportion of both D. immitis and wDi genes display microfilarial-biased transcriptional patterns.Concurrent transcriptome sequencing identified potential molecular interactions between parasite and endosymbiont that are more prominent during certain life cycle stages.In support of metabolite provisioning between filarial nematodes and Wolbachia, the synthesis of the critical metabolite, heme, by wDi appears to be synchronized in a stage-specific manner (mf-specific) with the production of heme-binding proteins in D. immitis.

View Article: PubMed Central - PubMed

Affiliation: Department of Biology and Microbiology, University of Wisconsin Oshkosh, Oshkosh, WI 54901, USA. michalsk@uwosh.edu.

ABSTRACT

Background: Dirofilaria immitis, or canine heartworm, is a filarial nematode parasite that infects dogs and other mammals worldwide. Current disease control relies on regular administration of anthelmintic preventives, however, relatively poor compliance and evidence of developing drug resistance could warrant alternative measures against D. immitis and related human filarial infections be taken. As with many other filarial nematodes, D. immitis contains Wolbachia, an obligate bacterial endosymbiont thought to be involved in providing certain critical metabolites to the nematode. Correlations between nematode and Wolbachia transcriptomes during development have not been examined. Therefore, we detailed the developmental transcriptome of both D. immitis and its Wolbachia (wDi) in order to gain a better understanding of parasite-endosymbiont interactions throughout the nematode life cycle.

Results: Over 215 million single-end 50 bp reads were generated from total RNA from D. immitis adult males and females, microfilariae (mf) and third and fourth-stage larvae (L3 and L4). We critically evaluated the transcriptomes of the various life cycle stages to reveal sex-biased transcriptional patterns, as well as transcriptional differences between larval stages that may be involved in larval maturation. Hierarchical clustering revealed both D. immitis and wDi transcriptional activity in the L3 stage is clearly distinct from other life cycle stages. Interestingly, a large proportion of both D. immitis and wDi genes display microfilarial-biased transcriptional patterns. Concurrent transcriptome sequencing identified potential molecular interactions between parasite and endosymbiont that are more prominent during certain life cycle stages. In support of metabolite provisioning between filarial nematodes and Wolbachia, the synthesis of the critical metabolite, heme, by wDi appears to be synchronized in a stage-specific manner (mf-specific) with the production of heme-binding proteins in D. immitis.

Conclusions: Our integrated transcriptomic study has highlighted interesting correlations between Wolbachia and D. immitis transcription throughout the life cycle and provided a resource that may be used for the development of novel intervention strategies, not only for the treatment and prevention of D. immitis infections, but of other closely related human parasites as well.

Show MeSH
Related in: MedlinePlus