Review article: Fly research & COVID-19

"Remarkably, 90% of the SARS-CoV-2 virus-host interacting proteins are conserved between Drosophila and humans."

 

Cell Biosci. 2021 Jun 13;11(1):110. doi: 10.1186/s13578-021-00621-5.

Drosophila, a powerful model to study virus-host interactions and pathogenicity in the fight against SARS-CoV-2

van de Leemput J, Han Z

Abstract:

"The COVID-19 pandemic is having a tremendous impact on humanity. Although COVID-19 vaccines are showing promising results, they are not 100% effective and resistant mutant SARS-CoV-2 strains are on the rise. To successfully fight against SARS-CoV-2 and prepare for future coronavirus outbreaks, it is essential to understand SARS-CoV-2 protein functions, their host interactions, and how these processes convey pathogenicity at host tissue, organ and systemic levels. In vitro models are valuable but lack the physiological context of a whole organism. Current animal models for SARS-CoV-2 research are exclusively mammals, with the intrinsic limitations of long reproduction times, few progeny, ethical concerns and high maintenance costs. These limitations make them unsuitable for rapid functional investigations of virus proteins as well as genetic and pharmacological screens. Remarkably, 90% of the SARS-CoV-2 virus-host interacting proteins are conserved between Drosophila and humans. As a well-established model system for studying human diseases, the fruit fly offers a highly complementary alternative to current mammalian models for SARS-CoV-2 research, from investigating virus protein function to developing targeted drugs. Herein, we review Drosophila's track record in studying human viruses and discuss the advantages and limitations of using fruit flies for SARS-CoV-2 research. We also review studies that already used Drosophila to investigate SARS-CoV-2 protein pathogenicity and their damaging effects in COVID-19 relevant tissues, as well as studies in which the fly was used as an efficient whole animal drug testing platform for targeted therapeutics against SARS-CoV-2 proteins or their host interacting pathways."

DOI: 10.1186/s13578-021-00621-5
PMCID: PMC8200282
PMID: 34120640

Preprint: ORF3a protein from the virus that causes COVID-19 is pathogenic in Drosophila

SARS-CoV-2 protein ORF3a is pathogenic in Drosophila and causes phenotypes associated with COVID-19 post-viral syndrome

Shuo Yang, Meijie Tian, Aaron N. Johnson 

Summary: The Coronavirus Disease 2019 (COVID-19) pandemic has caused millions of deaths and will continue to exact incalculable tolls worldwide. While great strides have been made toward understanding and combating the mechanisms of Severe Acute Respiratory Syndrome Coronavirus-2 (SARS-CoV-2) infection, relatively little is known about the individual SARS-CoV-2 proteins that contribute to pathogenicity during infection and that cause neurological sequela after viral clearance. We used Drosophila to develop an in vivo model that characterizes mechanisms of SARS-CoV-2 pathogenicity, and found ORF3a adversely affects longevity and motor function by inducing apoptosis and inflammation in the nervous system. Chloroquine alleviated ORF3a induced phenotypes in the CNS, arguing our Drosophila model is amenable to high throughput drug screening. Our work provides novel insights into the pathogenic nature of SARS-CoV-2 in the nervous system that can be used to develop new treatment strategies for post-viral syndrome.

https://www.biorxiv.org/content/10.1101/2020.12.20.423533v1

Article discusses potential use of Drosophila in COVID-19 / SARS-CoV-2 related studies

Front Pharmacol. 2020; 11: 588561.

Potential Application of Drosophila melanogaster as a Model Organism in COVID-19-Related Research
Firzan Nainu, Dini Rahmatika, Talha Bin Emran, and Harapan Harapan

Published online 2020 Sep 4. doi: 10.3389/fphar.2020.588561

[No abstract]

PMCID: PMC7500409
PMID: 33013425

Click here to access the article at PubMed Central.

Drosophila used in study of receptor for entry into cells of disease-causing viruses

Zhang R, Earnest JT, Kim AS, Winkler ES, Desai P, Adams LJ, Hu G, Bullock C, Gold B, Cherry S, Diamond MS. Expression of the Mxra8 Receptor Promotes Alphavirus Infection and Pathogenesis in Mice and Drosophila. Cell Rep. 2019 Sep 3;28(10):2647-2658.e5. doi: 10.1016/j.celrep.2019.07.105. PubMed PMID: 31484075; PubMed Central PMCID: PMC6745702.

From the abstract: "Mxra8 is a recently described receptor for multiple alphaviruses, including Chikungunya (CHIKV), Mayaro (MAYV), Ross River (RRV), and O'nyong nyong (ONNV) viruses. ... Ectopic Mxra8 expression is sufficient to enhance CHIKV infection and lethality in transgenic flies. ... targeting this protein may mitigate disease in humans."

How to lurk: Droosphila used in study related to attachment of the cholera-causing bacteria Vibrio cholerae to arthropod intestines

Kamareddine L, Wong ACN, Vanhove AS, Hang S, Purdy AE, Kierek-Pearson K, Asara JM, Ali A, Morris JG Jr, Watnick PI. Activation of Vibrio cholerae quorum sensing promotes survival of an arthropod host. Nat Microbiol. 2018 Feb;3(2):243-252. PMID: 29180725; PMCID: PMC6260827.

Abstract: "Vibrio cholerae colonizes the human terminal ileum to cause cholera, and the arthropod intestine and exoskeleton to persist in the aquatic environment. Attachment to these surfaces is regulated by the bacterial quorum-sensing signal transduction cascade, which allows bacteria to assess the density of microbial neighbours. Intestinal colonization with V. cholerae results in expenditure of host lipid stores in the model arthropod Drosophila melanogaster. Here we report that activation of quorum sensing in the Drosophila intestine retards this process by repressing V. cholerae succinate uptake. Increased host access to intestinal succinate mitigates infection-induced lipid wasting to extend survival of V. cholerae-infected flies. Therefore, quorum sensing promotes a more favourable interaction between V. cholerae and an arthropod host by reducing the nutritional burden of intestinal colonization."

Asking yourself, "Um, what?" Here's an interpretation by your blog author: 

Bacteria called Vibrio cholerae cause cholera in humans. When they're not doing that, they lurk inside the guts (and on the outsides) of arthropods that live in the water. This study uses fruit flies as a lab-friendly system in which to look at a specific aspect of the interaction between a host arthropod's gut and Vibrio bacteria. Turns out that confusing the bacteria about how many of themselves are around stops them from taking up a molecule called succinate, leaving more of the succinate around for the fly. With more succinate available, the fly uses up less of its fat reserves than it usually would when infected. This helps the infected fly survive longer.

Fly Study Points to Bacterial Regulation of Acetate as Factor in Vibrio cholera virulence

Liimatta K, Flaherty E, Ro G, Nguyen DK, Prado C, Purdy AE. A putative acetylation system in Vibrio cholerae modulates virulence in arthropod hosts. Appl Environ Microbiol. 2018 Aug 24. PMID: 30143508.

From the abstract: "Acetylation is a broadly conserved mechanism of covalently modifying the proteome to precisely control protein activity. In bacteria, central metabolic enzymes and regulatory proteins, including those involved in virulence, can be targeted for acetylation. In this study, we directly link a putative acetylation system to metabolite-dependent virulence in the pathogen Vibrio cholerae ... The Drosophila model of Vibrio cholerae infection has revealed that bacterial regulation of acetate and other small metabolites from within the fly gastrointestinal tract is crucial to its virulence. Here, we demonstrate that genes that may modify the proteome of V. cholerae affect virulence towards Drosophila ... These findings further highlight the many layers of regulation that tune bacterial metabolism to alter the trajectory of interactions between bacteria and their hosts."

Using fruit flies and house flies to study cholera

Purdy AE. Fly Models of Vibrio cholerae Infection and Colonization. Methods Mol Biol. 2018;1839:77-96. doi: 10.1007/978-1-4939-8685-9_8. PubMed PMID: 30047056.

From the abstract: "Studies of Vibrio cholerae pathogenesis in the context of novel eukaryotic model systems have expanded our understanding of genes that underlie V. cholerae interactions with humans, as well as host organisms in the environment. ... The Drosophila model for V. cholerae infection is a powerful tool for discovering new genetic pathways that govern bacterial physiology and colonization in the arthropod gastrointestinal tract. Assays to measure both virulence and colonization have been established and are easily adopted in labs unfamiliar with Drosophila work. Experiments to compare survival of flies colonized with different bacterial mutants are simple to perform and can be completed in less than a week, allowing colonization to be quantified and localized easily. The availability of molecular and genetic tools for the fly enables further exploration of host factors that restrict V. cholerae colonization and invasive infection. Based on the Drosophila system, a house fly (Musca domestica) model of V. cholerae colonization has also been developed. The new house fly model may prove a useful tool for examining V. cholerae infection dynamics in the context of a host carrying a complex microbial community, with a fundamentally different ecology that may increase its chances of acting as a vector for cholera disease."

Fly model of cholera used to explore cellular mechanisms of disease

Fast D, Kostiuk B, Foley E, Pukatzki S. Commensal pathogen competition impacts host viability. Proc Natl Acad Sci U S A. 2018 Jul 3;115(27):7099-7104. PMID: 29915049.

From the abstract: "While the structure and regulatory networks that govern type-six secretion system (T6SS) activity of Vibrio cholerae are becoming increasingly clear, we know less about the role of T6SS in disease. Under laboratory conditions, V. cholerae uses T6SS to outcompete many Gram-negative species, including other V. cholerae strains and human commensal bacteria. ... We used the Drosophila melanogaster model of cholera to define the contribution of T6SS to V. cholerae pathogenesis. ... interactions between T6SS and host commensals impact pathogenesis. Inactivation of T6SS, or removal of commensal bacteria, attenuates disease severity. Reintroduction of the commensal, Acetobacter pasteurianus, into a germ-free host is sufficient to restore T6SS-dependent pathogenesis in which T6SS and host immune responses regulate viability. Together, our data demonstrate that T6SS acts on commensal bacteria to promote the pathogenesis of V. cholerae."

Drosophila gut as model for uncovering mechanisms of antimicrobial activity

Liu X, Hodgson JJ, Buchon N. Drosophila as a model for homeostatic,antibacterial, and antiviral mechanisms in the gut. PLoS Pathog. 2017 May 4;13(5):e1006277. PMID: 28472194; PMCID: PMC5417715.

This review article includes an illustrated comparison of fly and mammalian guts and their interactions with microbes such as bacteria and viruses.

Protocol for infection of Drosophila with a parasite for research studies related to leishmaniasis

Okuda K, Silverman N. Drosophila Model of Leishmania amazonensis Infection. Bio Protoc. 2017 Dec 5;7(23). pii: e2640. PMID: 29276726; PMCID: PMC5738924.

The abstract: "This protocol describes how to generate and harvest antibody-free L. amazonensis amastigotes, and how to infect adult Drosophila melanogaster with these parasites. This model recapitulates key aspects of the interactions between Leishmania amastigotes and animal phagocytes."

No lung? No problem. Invertebrate models in the study of lung infections.

López Hernández Y, Yero D, Pinos-Rodríguez JM, Gibert I. Animals devoid of pulmonary system as infection models in the study of lung bacterial pathogens. Front Microbiol. 2015 Feb 4;6:38. PMID: 25699030; PMCID: PMC4316775.

From the abstract: “… in vivo lung infection models performed to study lung pathologies use to be laborious, demand a great time and commonly are associated with ethical issues. When infections in experimental animals are used, they need to be refined, defined, and validated for their intended purpose. Therefore, alternative and easy to handle models of experimental infections are still needed ... Here, we review the use of … vertebrate and non-vertebrate models in the study of bacterial agents, which are considered the principal causes of lung injury. Curiously none of these animals have a respiratory system as in air-breathing vertebrates, where respiration takes place in lungs. Despite this fact, with the present review we sought to provide elements in favor of the use of these alternative animal models of infection to reveal the molecular signatures of host-pathogen interactions.”

Results of cross-species study suggest Pseudomonas aeruginosa virulence factors are largely host-specific

Dubern JF, Cigana C, De Simone M, Lazenby J, Juhas M, Schwager S, Bianconi I, Döring G, Eberl L, Williams P, Bragonzi A, Cámara M. Integrated whole genome screening for Pseudomonas aeruginosa virulence genes using multiple disease models reveals that pathogenicity is host specific. Environ Microbiol. 2015 Apr 3. doi: 10.1111/1462-2920.12863. PMID: 25845292.

From the abstract: "Pseudomonas aeruginosa is a multi-host opportunistic pathogen causing a wide range of diseases ... Using an integrated whole-genome approach we searched for P. aeruginosa virulence genes with multi-host relevance. ... pleotropic mutants were assayed for reduced toxicity in Drosophila melanogaster, Caenorhabditis elegans, human cell lines, and mice. Surprisingly, the screening revealed that the virulence of the majority of P. aeruginosa mutants varied between disease models ... These findings have important implication when searching for novel anti-virulence targets to develop new treatments against P. aeruginosa."

Review--Drosophila as a model for development of novel therapeutics to fight infection

Tzelepis I, Kapsetaki SE, Panayidou S, Apidianakis Y. Drosophila melanogaster: a first step and a stepping-stone to anti-infectives. Curr Opin Pharmacol. 2013 Oct;13(5):763-8. PMID: 23992884.

From the abstract: "Following an expansion in the antibiotic drug discovery in the previous century, we now face a bottleneck in the production of new anti-infective drugs. ... Drug screening in Drosophila offers to fill the gap between in vitro and mammalian model host testing ... alternative screening methods in Drosophila, while low-throughput, may reduce the cost and increase the success rate of preclinical trials."

Cholera and Notch signaling--study includes fly assays

Guichard A, Cruz-Moreno B, Aguilar B, van Sorge NM, Kuang J, Kurkciyan AA, Wang Z, Hang S, Pineton de Chambrun GP, McCole DF, Watnick P, Nizet V, Bier E. Cholera toxin disrupts barrier function by inhibiting exocyst-mediated trafficking of host proteins to intestinal cell junctions. Cell Host Microbe. 2013 Sep 11;14(3):294-305. PMID: 24034615; PMCID: PMC3786442.

Fly cell study identifies conserved host cell factors related to West Nile Virus infection

Yasunaga A, Hanna SL, Li J, Cho H, Rose PP, Spiridigliozzi A, Gold B, Diamond MS, Cherry S. Genome-Wide RNAi Screen Identifies Broadly-Acting Host Factors That Inhibit Arbovirus Infection. PLoS Pathog. 2014 Feb 13;10(2):e1003914. PMID: 24550726; PMCID: PMC3923753.


From the abstract:  "Investigation of two newly identified factors that restrict diverse viruses, dXPO1 and dRUVBL1, in the Tip60 complex, demonstrated they contributed to antiviral defense at the organismal level in adult flies, in mosquito cells, and in mammalian cells. These data suggest the existence of broadly acting and functionally conserved antiviral genes and pathways that restrict virus infections in evolutionarily divergent hosts."

Review: study of infectious pathogens in the fly model

Panayidou S, Ioannidou E, Apidianakis Y. Human pathogenic bacteria, fungi, and viruses in Drosophila: Disease modeling, lessons, and shortcomings. Virulence. 2014 Jan 7;5(2). PMID: 24398387.

Relevant review--fly model & host defense

Ferrandon D. The complementary facets of epithelial host defenses in the genetic model organism Drosophila melanogaster: from resistance to resilience. Curr Opin Immunol. 2013 Feb;25(1):59-70. Review. PMID: 23228366.

Review includes discussion of fly models of fungal infection

Arvanitis M, Glavis-Bloom J, Mylonakis E. Invertebrate models of fungal infection. Biochim Biophys Acta. 2013 Sep;1832(9):1378-83. PMID: 23517918.

From the abstract: "The purpose of this review is to compare several model hosts that have been used in experimental mycology to-date and to describe their different characteristics and contribution to the study of fungal virulence and the detection of compounds with antifungal properties."

New fly model--pythiosis

Zanette RA, Santurio JM, Loreto ES, Alves SH, Kontoyiannis DP. Toll-deficient Drosophila is susceptible to Pythium insidiosum infection. Microbiol Immunol. 2013 Jul 19. PMID: 23865688.

From the abstract: "There is a paucity of animal models of pythiosis, a life-threatening disease of humans and animals that has poorly understood immunopathogenesis. We developed a pythiosis model ..."

Flies & infection.

Ben-Ami R, Watson CC, Lewis RE, Albert ND, Arias CA, Raad II, Kontoyiannis DP. Drosophila melanogaster as a model to explore the effects of methicillin-resistant Staphylococcus aureus strain type on virulence and response to linezolid treatment. Microb Pathog. 2013 Feb;55:16-20. PMID: 23232438.

Diaz L, Kontoyiannis DP, Panesso D, Albert ND, Singh KV, Tran TT, Munita JM, Murray BE, Arias CA. Dissecting the mechanisms of linezolid resistance in a Drosophila melanogaster infection model of Staphylococcus aureus. J Infect Dis. 2013 Jul;208(1):83-91. PMID: 23547139; PMCID: PMC3666140.


See also this post.