Dataset Information

Ribosomal/nucleolar stress induction regulates tert-butyl hydroperoxide (tBHP) mediated oxidative stress in Anopheles gambiae midguts

ABSTRACT: A general understanding of redox homeostasis in An. gambiae midgut epithelial cells under different oxidative conditions during P. falciparum ookinete invasion is missing. We used an ex vivo midgut culture model to understand AgTrx-1 protein expression pattern in An. gambiae midguts under oxidative stress of the ROS inducer, tert-butyl hydroperoxide (tBHP). We then quantified the midgut proteomic expression profile to understand organ-level regulation of the response to oxidative stress. An. gambiae midguts under low (50M) and high (200M) tBHP concentrations were enriched in ribosomal proteins (RPs), consistent with cells undergoing ribosomal/nucleolar stress. Nevertheless, these midguts were also enriched in peptidases, integral membrane proteins, and cytochrome P450s indicating cells that are undergoing protein processing and folding through post-translational modification (PTMs), and detoxification of toxic compounds through active efflux. This response to oxidative stress was strikingly dissimilar to that observed from previous studies with another dipteran, Drosophila following oxidative stress induction. Our data indicates that the response to tBHP induced oxidative stress is mild and suggests that the associated antioxidant response is similar to what is observed during midgut invasion of P. falciparum okinete. Furthermore, our data shows that ribosomal/nucleolar stress is crucial in the regulation of oxidative stress in An. gambiae midguts. Given this importance, its possible to develop mechanisms to perturb this ribosomal/nucleolar stress response in An. gambiae resulting into unmanageable levels of oxidative stress exposure to Plasmodium parasite in the midgut, yet still allowing the mosquito to survive the perturbation. Unmanageable levels of oxidative stress could result to harmful effect to the Plasmodium and eventually its death resulting into halting of its transmission.

INSTRUMENT(S): 6520A Quadrupole Time-of-Flight LC/MS

ORGANISM(S): Anopheles Gambiae (african Malaria Mosquito)

TISSUE(S): Midgut

DISEASE(S): Malaria

SUBMITTER: Chun Hin Law

LAB HEAD: Rhoel Dinglasan

PROVIDER: PXD008251 | Pride | 2018-11-21

REPOSITORIES: Pride

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			Action	DRS
	AgambieHighB01-03vsContB01-B03.sf3	Other
	AgambieHighB01-03vsLowB01-B03.sf3	Other
	AgambieHighB01.zip	Other
	AgambieHighB01_search.rar	Other
	AgambieHighB02.zip	Other

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Publications

Paraquat-Mediated Oxidative Stress in <i>Anopheles gambiae</i> Mosquitoes Is Regulated by An Endoplasmic Reticulum (ER) Stress Response.

Tarimo Brian B BB Law Henry Chun Hin HCH Tao Dingyin D Pastrana-Mena Rebecca R Kanzok Stefan M SM Buza Joram J JJ Dinglasan Rhoel R RR

Proteomes 20181112 4

Paraquat is a potent superoxide (O₂<sup>-</sup>)-inducing agent that is capable of inducing an oxidative imbalance in the mosquito midgut. This oxidative imbalance can super-stress the malaria parasite, leading to arrested development in the mosquito midgut and reduced transmission. While several studies have explored the effect of paraquat on malaria parasites, a fundamental understanding of the mosquito response to this compound remains unknown. Here, we quantified the mosquito midgut proteomi ...[more]

PMID: 30424486

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Project description:The mosquito Anopheles gambiae uses its innate immune system to control bacterial and Plasmodium infection of its midgut tissue. The activation of potent IMD pathway-mediated anti-Plasmodium falciparum defenses is dependent on the presence of the midgut microbiota, which activate this defense system upon parasite infection through a peptidoglycan recognition protein, PGRPLC. We employed transcriptomic and reverse genetic analyses to compare the P. falciparum infection-responsive transcriptomes of septic and aseptic mosquitoes and to determine whether bacteria-independent anti-Plasmodium defenses exist. To examine the impact of P. falciparum infection on the mosquito midgut and carcass transcriptomes in the presence or absence of midgut bacteria, we used A. gambiae whole genome microarrays to compare the mRNA abundance of P. falciparum-infected and -naÃ¯ve mosquitoes of antibiotic- and non-antibiotic treated cohorts. P. falciparum infection induced changes in the abundance of as many as 2,183 and 2,429 transcripts in whole mosquitoes belonging to a variety of functional groups in aseptic and septic mosquitoes. Ultimately, we were interested in identifying the genes involved in bacteria-independent anti-Plasmodium responses, and therefore we focused on transcripts displaying increased abundance in the parasite-infected aseptic midguts, placing a particular emphasis on those with predicted immune functions. Because of the central role of serine protease cascades in regulating insect immune defenses, we focused the remainder of our analysis on a clip-domain serine protease C2 (CLIPC2, AGAP004317) and a serine protease inhibitor 7 (SRPN7, AGAP007693) that were specifically upregulated in the parasite-infected, aseptic mosquito midgut. We showed that SRPN7 negatively and CLIPC2 positively regulate the anti-Plasmodium defense, independently of the midgut-associated bacteria. Co-silencing assays suggested that these two genes may function together in a signaling cascade. Neither gene was regulated, nor modulated, by infection with the rodent malaria parasite Plasmodium berghei, suggesting that SRPN7 and CLIPC2 are components of a defense system with preferential activity towards P. falciparum. Further analysis using RNA interference determined that these genes do not regulate the anti-Plasmodium defense mediated by the IMD pathway, and both factors act as agonists of the endogenous midgut microbiota, further demonstrating the lack of functional relatedness between these genes and the bacteria-dependent activation of the IMD pathway. This is the first study confirming the existence of a bacteria-independent, anti-P. falciparum defense. Aseptic and septic midguts and carcasses from P. falciparum-infected A. gambiae vs aseptic and septic midguts and carcasses from uninfected, blood-fed A. gambiae. 3 biological replicates and 1 pseudo-replicate per each array.

Project description:A deeper understanding of malaria parasite development inside the Anopheles mosquito may lead to the identification of processes that can be targeted by transmission-blocking interventions. Paraquat (1,1'-dimethyl-4,4'-bipyridylium dichloride) is a potent superoxide-inducing agent that impacts Plasmodium ookinete development, especially at higher concentrations. Compounds like Paraquat can potentially induce an oxidative imbalance in the mosquito midgut during ookinete maturation, essentially super-stressing the parasite leading to the arrested development of ookinetes, the only stage that can invade through a mosquito midgut cell to establish an oocyst infection in the mosquito. The mosquito midgut has evolved to handle the natural production of reactive oxygen and nitrogen species (ROS and RNS, respectively) as a result of feeding on blood. The addition of Paraquat to a bloodmeal is expected to induce a cognate response in the midgut to handle the excess ROS/RNS, and high concentrations of this compound can potentially overwhelm the midgut response leading to mosquito death. While several studies have explored the effect of Paraquat on malaria parasites, a fundamental understanding of the mosquito response to this compound remains unknown. Here, we quantified the mosquito midgut proteomic response to a Paraquat-laced sugar meal to understand the intrinsic midgut response (in the absence of a bloodmeal). We then carried out transcriptomic analysis of the mosquito midgut for several antioxidants of the Trx and GSH pathways to compare concordance or discordance between protein and its transcripts during different oxidative stress conditions. Finally, we determined whether the same Trx and GSH pathways are upregulated following infection with either P. falciparum or P. berghei at 24 hrs post-blood feeding, coinciding with the time point for maximal ookinete traversal of the midgut. We discuss the potential selective action of Paraquat on the parasite and the intrinsic tolerance of the mosquito midgut to Paraquat-mediated oxidative stress.

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