Identification of putative effectors of the Type IV secretion system from the Wolbachia endosymbiont of Brugia malayi

Carpinone, Emily M.; Li, Zhi‐Ru; Mills, Michael K.; Foltz, Clémence; Brannon, Emma R.; Carlow, Clotilde K. S.; Starai, Vincent J.

doi:10.1371/journal.pone.0204736

Cited by 23 publications

(36 citation statements)

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“…Alternatively, treatment timelines can be expanded to assess more cumulative effects across life cycle stages. It will be possible to further explore other processes implicated in germline titer control, such as Wolbachia impacts on actin polymerization [21, 52, 83, 84] and vesicle trafficking pathways [4, 5, 85–89] relevant to oogenesis. Our methodology will translate readily across other Wolbachia/ host combinations, and may be adapted to other insect tissues or possibly endosymbiont/host models.…”

Section: Discussionmentioning

confidence: 99%

Quantitative methods for assessing local and bodywide contributions to Wolbachia titer in maternal germline cells of Drosophila

et al. 2019

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Background Little is known about how bacterial endosymbionts colonize host tissues. Because many insect endosymbionts are maternally transmitted, egg colonization is critical for endosymbiont success. Wolbachia bacteria, carried by approximately half of all insect species, provide an excellent model for characterizing endosymbiont infection dynamics. To date, technical limitations have precluded stepwise analysis of germline colonization by Wolbachia. It is not clear to what extent titer-altering effects are primarily mediated by growth rates of Wolbachia within cell lineages or migration of Wolbachia between cells. Results The objective of this work is to inform mechanisms of germline colonization through use of optimized methodology. The approaches are framed in terms of nutritional impacts on Wolbachia . Yeast-rich diets in particular have been shown to suppress Wolbachia titer in the Drosophila melanogaster germline. To determine the extent of Wolbachia sensitivity to diet, we optimized 3-dimensional, multi-stage quantification of Wolbachia titer in maternal germline cells. Technical and statistical validation confirmed the identity of Wolbachia in vivo , the reproducibility of Wolbachia quantification and the statistical power to detect these effects. The data from adult feeding experiments demonstrated that germline Wolbachia titer is distinctly sensitive to yeast-rich host diets in late oogenesis. To investigate the physiological basis for these nutritional impacts, we optimized methodology for absolute Wolbachia quantification by real-time qPCR. We found that yeast-rich diets exerted no significant effect on bodywide Wolbachia titer, although ovarian titers were significantly reduced. This suggests that host diets affects Wolbachia distribution between the soma and late stage germline cells. Notably, relative qPCR methods distorted apparent wsp abundance, due to altered host DNA copy number in yeast-rich conditions. This highlights the importance of absolute quantification data for testing mechanistic hypotheses. Conclusions We demonstrate that absolute quantification of Wolbachia, using well-controlled cytological and qPCR-based methods, creates new opportunities to determine how bacterial abundance within the germline relates to bacterial distribution within the body. This methodology can be applied to further test germline infection dynamics in response to chemical treatments, genetic conditions, new host/endosymbiont combinations, or potentially ada...

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Section: Discussionmentioning

confidence: 99%

Quantitative methods for assessing local and bodywide contributions to Wolbachia titer in maternal germline cells of Drosophila

et al. 2019

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“…These are the next questions to be addressed. In parallel, the current growing efforts to express the putative Wb effectors into surrogate systems [ 64 , 65 ], yeast or Drosophila cell cultures, should accelerate our knowledge of one of the most commonly encountered endosymbiont.…”

Section: Discussionmentioning

confidence: 99%

Wolbachia endosymbionts subvert the endoplasmic reticulum to acquire host membranes without triggering ER stress

2019

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The reproductive parasites Wolbachia are the most common endosymbionts on earth, present in a plethora of arthropod species. They have been introduced into mosquitos to successfully prevent the spread of vector-borne diseases, yet the strategies of host cell subversion underlying their obligate intracellular lifestyle remain to be explored in depth in order to gain insights into the mechanisms of pathogen-blocking. Like some other intracellular bacteria, Wolbachia reside in a host-derived vacuole in order to replicate and escape the immune surveillance. Using here the pathogen-blocking Wolbachia strain from Drosophila melanogaster, introduced into two different Drosophila cell lines, we show that Wolbachia subvert the endoplasmic reticulum to acquire their vacuolar membrane and colonize the host cell at high density. Wolbachia redistribute the endoplasmic reticulum, and time lapse experiments reveal tight coupled dynamics suggesting important signalling events or nutrient uptake. Wolbachia infection however does not affect the tubular or cisternal morphologies. A fraction of endoplasmic reticulum becomes clustered, allowing the endosymbionts to reside in between the endoplasmic reticulum and the Golgi apparatus, possibly modulating the traffic between these two organelles. Gene expression analyses and immunostaining studies suggest that Wolbachia achieve persistent infections at very high titers without triggering endoplasmic reticulum stress or enhanced ERAD-driven proteolysis, suggesting that amino acid salvage is achieved through modulation of other signalling pathways.

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“…It is noteworthy that other stress genes or chaperones (bolA, grpE, htpG, hslV, groEL) are also upregulated, although none of them in a significant manner (FDR>0.01, Fig 2B and Table 2). Since wBm possesses a functional type IV secretion system (T4SS), we identified the expression levels of the identified putative wBm effectors [31]. We did not find any significant variations between the different samples, suggesting that the cellular environments in the adult female do not influence the expression of the putative wBm T4SS effectors.…”

Section: Plos Neglected Tropical Diseases Wbm Gene Expression Levels mentioning

confidence: 89%

“…This demonstrates that wBm are necessary for maintenance of a functional germline that relies heavily on its endosymbionts in the earliest steps of oogenesis, in the proliferative zone. Wolbachia possess a functional type IV secretion system, that allows them to secrete potential effectors able to subvert the host biology to promote their survival and replication [24,31]. It is not clear yet whether wBm can differentially express genes, including putative effectors, between somatic and germline tissues, and during the different stages of oogenesis.…”

Section: Introductionmentioning

confidence: 99%

Dual RNAseq analyses at soma and germline levels reveal evolutionary innovations in the elephantiasis-agent Brugia malayi, and adaptation of its Wolbachia endosymbionts

Chevignon

Foray²,

Pérez-Jiménez³

et al. 2021

PLoS Negl Trop Dis

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Brugia malayi is a human filarial nematode responsible for elephantiasis, a debilitating condition that is part of a broader spectrum of diseases called filariasis, including lymphatic filariasis and river blindness. Almost all filarial nematode species infecting humans live in mutualism with Wolbachia endosymbionts, present in somatic hypodermal tissues but also in the female germline which ensures their vertical transmission to the nematode progeny. These α-proteobacteria potentially provision their host with essential metabolites and protect the parasite against the vertebrate immune response. In the absence of Wolbachia wBm, B. malayi females become sterile, and the filarial nematode lifespan is greatly reduced. In order to better comprehend this symbiosis, we investigated the adaptation of wBm to the host nematode soma and germline, and we characterized these cellular environments to highlight their specificities. Dual RNAseq experiments were performed at the tissue-specific and ovarian developmental stage levels, reaching the resolution of the germline mitotic proliferation and meiotic differentiation stages. We found that most wBm genes, including putative effectors, are not differentially regulated between infected tissues. However, two wBm genes involved in stress responses are upregulated in the hypodermal chords compared to the germline, indicating that this somatic tissue represents a harsh environment to which wBm have adapted. A comparison of the B. malayi and C. elegans germline transcriptomes reveals a poor conservation of genes involved in the production of oocytes, with the filarial germline proliferative zone relying on a majority of genes absent from C. elegans. The first orthology map of the B. malayi genome presented here, together with tissue-specific expression enrichment analyses, indicate that the early steps of oogenesis are a developmental process involving genes specific to filarial nematodes, that likely result from evolutionary innovations supporting the filarial parasitic lifestyle.

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Identification of putative effectors of the Type IV secretion system from the Wolbachia endosymbiont of Brugia malayi

Cited by 23 publications

References 100 publications

Quantitative methods for assessing local and bodywide contributions to Wolbachia titer in maternal germline cells of Drosophila

Quantitative methods for assessing local and bodywide contributions to Wolbachia titer in maternal germline cells of Drosophila

Wolbachia endosymbionts subvert the endoplasmic reticulum to acquire host membranes without triggering ER stress

Dual RNAseq analyses at soma and germline levels reveal evolutionary innovations in the elephantiasis-agent Brugia malayi, and adaptation of its Wolbachia endosymbionts

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