Functional analysis of SARS-CoV-2 proteins in Drosophila identifies Orf6-induced pathogenic effects with Selinexor as an effective treatment

Targeting XPO1 for fighting relapsed/refractory diseases: The research progress of XPO1 inhibitors

XPO1 is an influential member of the nuclear transporter protein family. The proteins and RNA transported by XPO1 are related to the occurrence and development of many diseases, including refractory tumor diseases and various viral infectious diseases. XPO1 is upregulated in many malignant tumors and is associated with poor prognosis. This article reviews the anti-tumor and anti-viral mechanisms of XPO1, and summarizes the biomarkers that predict the response to XPO1 inhibitors and the research progress of XPO1 as a biomarker in different diseases. In addition, we also summarize the research status of XPO1 inhibitors, and discuss the structure-activity relationship of preclinical inhibitors targeting XPO1 and the research status of XPO1 inhibitor resistance mechanisms.

SARS-CoV-2 membrane protein induces neurodegeneration via affecting Golgi-mitochondria interaction

BACKGROUND

Neurological complications are a significant concern of Coronavirus Disease 2019 (COVID-19). However, the pathogenic mechanism of neurological symptoms associated with severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infection is poorly understood.

METHODS

We used Drosophila as a model to systematically analyze SARS-CoV-2 genes encoding structural and accessory proteins and identified the membrane protein (M) that disrupted mitochondrial functions in vivo. The M protein was stereotaxically injected to further assess its effects in the brains of wild-type (WT) and 5 × FAD mice. Omics technologies, including RNA sequencing and interactome analysis, were performed to explore the mechanisms of the effects of M protein both in vitro and in vivo.

RESULTS

Systematic analysis of SARS-CoV-2 structural and accessory proteins in Drosophila identified that the M protein induces mitochondrial fragmentation and dysfunction, leading to reduced ATP production, ROS overproduction, and eventually cell death in the indirect flight muscles. In WT mice, M caused hippocampal atrophy, neural apoptosis, glial activation, and mitochondrial damage. These changes were further aggravated in 5 × FAD mice. M was localized to the Golgi apparatus and genetically interacted with four wheel drive (FWD, a Drosophila homolog of mammalian PI4KIIIβ) to regulate Golgi functions in flies. Fwd RNAi, but not PI4KIIIα RNAi, reversed the M-induced Golgi abnormality, mitochondrial fragmentation, and ATP reduction. Inhibition of PI4KIIIβ activity suppressed the M-induced neuronal cell death. Therefore, M induced mitochondrial fragmentation and apoptosis likely through disruption of Golgi-derived PI(4)P-containing vesicles.

CONCLUSIONS

M disturbs the distribution and function of Golgi, leading to mitochondrial abnormality and eventually neurodegeneration via a PI4KIIIβ-mediated mechanism. This study reveals a potential mechanism for COVID-19 neurological symptoms and opens a new avenue for development of therapeutic strategies targeting SARS-CoV-2 M or mitochondria.

SARS-CoV-2 Nsp6-Omicron causes less damage to the Drosophila heart and mouse cardiomyocytes than ancestral Nsp6

A few years into the COVID-19 pandemic, the SARS-CoV-2 Omicron strain rapidly becomes and has remained the predominant strain. To date, Omicron and its subvariants, while more transmittable, appear to cause less severe disease than prior strains. To study the cause of this reduced pathogenicity we compare SARS-CoV-2 ancestral Nsp6 with Nsp6-Omicron, which we have previously identified as one of the most pathogenic viral proteins. Here, through ubiquitous expression in Drosophila, we show that ancestral Nsp6 causes both structural and functional damage to cardiac, muscular, and tracheal (lung) tissue, whereas Nsp6-Omicron has minimal effects. Moreover, we show that ancestral Nsp6 dysregulates the glycolysis pathway and disrupts mitochondrial function, whereas Nsp6-Omicron does not. Through validation in mouse primary cardiomyocytes, we find that Nsp6-induced dysregulated glycolysis underlies the cardiac dysfunction. Together, the results indicate that the amino acid changes in Omicron might hinder its interaction with host proteins thereby minimizing its pathogenicity.

Investigating SARS-CoV-2 virus-host interactions and mRNA expression: Insights using three models of D. melanogaster

Responsible for COVID-19, SARS-CoV-2 is a coronavirus in which contagious variants continue to appear. Therefore, some population groups have demonstrated greater susceptibility to contagion and disease progression. For these reasons, several researchers have been studying the SARS-CoV-2/human interactome to understand the pathophysiology of COVID-19 and develop new pharmacological strategies. D. melanogaster is a versatile animal model with approximately 90 % human protein orthology related to SARS-CoV-2/human interactome and is widely used in metabolic studies. In this context, our work assessed the potential interaction between human proteins (ZNF10, NUP88, BCL2L1, UBC9, and RBX1) and their orthologous proteins in D. melanogaster (gl, Nup88, Buffy, ubc9, and Rbx1a) with proteins from SARS-CoV-2 (nsp3, nsp9, E, ORF7a, N, and ORF10) using computational approaches. Our results demonstrated that all the proteins have the potential to interact, and we compared the binding sites between humans and fruit flies. The stability and consistency in the structure of the gl_nsp3 complex, specifically, could be crucial for its specific biological functions. Lastly, to enhance the understanding of the influence of host factors on coronavirus infection, we also analyse the mRNA expression of the five genes (mbo, gl, lwr, Buffy, and Roc1a) responsible for encoding the fruit fly proteins. Briefly, we demonstrated that those genes were differentially regulated according to diets, sex, and age. Two groups showed higher positive gene regulation than others: females in the HSD group and males in the aging group, which could imply a higher virus-host susceptibility. Overall, while preliminary, our work contributes to the understanding of host defense mechanisms and potentially identifies candidate proteins and genes for in vivo viral studies against SARS-CoV-2.

Mitochondria in COVID-19: from cellular and molecular perspective

The rapid development of the COVID-19 pandemic resulted in a closer analysis of cell functioning during β-coronavirus infection. This review will describe evidence for COVID-19 as a syndrome with a strong, albeit still underestimated, mitochondrial component. Due to the sensitivity of host mitochondria to coronavirus infection, SARS-CoV-2 affects mitochondrial signaling, modulates the immune response, modifies cellular energy metabolism, induces apoptosis and ageing, worsening COVID-19 symptoms which can sometimes be fatal. Various aberrations across human systems and tissues and their relationships with mitochondria were reported. In this review, particular attention is given to characterization of multiple alterations in gene expression pattern and mitochondrial metabolism in COVID-19; the complexity of interactions between SARS-CoV-2 and mitochondrial proteins is presented. The participation of mitogenome fragments in cell signaling and the occurrence of SARS-CoV-2 subgenomic RNA within membranous compartments, including mitochondria is widely discussed. As SARS-CoV-2 severely affects the quality system of mitochondria, the cellular background for aberrations in mitochondrial dynamics in COVID-19 is additionally characterized. Finally, perspectives on the mitigation of COVID-19 symptoms by affecting mitochondrial biogenesis by numerous compounds and therapeutic treatments are briefly outlined.

SARS-CoV2 Nsp3 protein triggers cell death and exacerbates amyloid β42-mediated neurodegeneration

Infection caused by the severe acute respiratory syndrome coronavirus 2 (SARS-CoV2) virus, responsible for the coronavirus disease 2019 (COVID-19) pandemic, induces symptoms including increased inflammatory response, severe acute respiratory syndrome (SARS), cognitive dysfunction like brain fog, and cardiovascular defects. Long-term effects of SARS-CoV2 COVID-19 syndrome referred to as post-COVID-19 syndrome on age-related progressive neurodegenerative disorders such as Alzheimer’s disease remain understudied. Using the targeted misexpression of individual SARS-CoV2 proteins in the retinal neurons of the Drosophila melanogaster eye, we found that misexpression of nonstructural protein 3 (Nsp3), a papain-like protease, ablates the eye and generates dark necrotic spots. Targeted misexpression of Nsp3 in the eye triggers reactive oxygen species production and leads to apoptosis as shown by cell death reporters, terminal deoxynucleotidyl transferase (TdT) dUTP Nick-end labeling (TUNEL) assay, and dihydroethidium staining. Furthermore, Nsp3 misexpression activates both apoptosis and autophagy mechanism(s) to regulate tissue homeostasis. Transient expression of SARS-CoV2 Nsp3 in murine neuroblastoma, Neuro-2a cells, significantly reduced the metabolic activity of these cells and triggers cell death. Misexpression of SARS-CoV2 Nsp3 in an Alzheimer’s disease transgenic fly eye model (glass multiple repeats [GMR]>amyloid β42) further enhances the neurodegenerative rough eye phenotype due to increased cell death. These findings suggest that SARS-CoV2 utilizes Nsp3 protein to potentiate cell death response in a neurodegenerative disease background that has high pre-existing levels of neuroinflammation and cell death.

Functional characterisation of the ACE2 orthologues in Drosophila provides insights into the neuromuscular complications of COVID-19

SARS-CoV-2, the virus responsible for the coronavirus disease of 2019 (COVID-19), gains cellular entry via interaction with the angiotensin-converting enzyme 2 (ACE2) receptor of host cells. Although SARS-CoV-2 mainly targets the respiratory system, the neuromuscular system also appears to be affected in a large percentage of patients with acute or chronic COVID-19. The cause of the well-described neuromuscular manifestations resulting from SARS-CoV-2 infection remains unresolved. These may result from the neuromuscular-invasive capacity of the virus leading to direct injury. Alternatively, they may be the consequence of ACE2 inactivation either due to viral infection, ACE2 autoantibodies or both. Here, we made use of the Drosophila model to investigate whether ACE2 downregulation is sufficient to induce neuromuscular phenotypes. We show that moderate gene silencing of ACE2 orthologues Ance or Ance3 diminished survival on exposure to thermal stress only upon induction of neuromuscular fatigue driven by increased physical activity. A strong knockdown of Ance or Ance3 directed to muscle reduced or abolished adult viability and caused obvious motoric deficits including reduced locomotion and impaired flight capacity. Selective knockdown of Ance and Ance3 in neurons caused wing defects and an age-dependent decline in motor behaviour, respectively, in adult flies. Interestingly, RNA sequencing allowed us to discover several differentially spliced genes that are required for synaptic function downstream of Ance or Ance3 depletion. Our findings are therefore supportive of the notion that loss of a RAS-independent function for ACE2 contributes to the neuromuscular manifestations associated with SARS-CoV-2 infection.

A comprehensive Drosophila resource to identify key functional interactions between SARS-CoV-2 factors and host proteins

Development of effective therapies against SARS-CoV-2 infections relies on mechanistic knowledge of virus-host interface. Abundant physical interactions between viral and host proteins have been identified, but few have been functionally characterized. Harnessing the power of fly genetics, we develop a comprehensive Drosophila COVID-19 resource (DCR) consisting of publicly available strains for conditional tissue-specific expression of all SARS-CoV-2 encoded proteins, UAS-human cDNA transgenic lines encoding established host-viral interacting factors, and GAL4 insertion lines disrupting fly homologs of SARS-CoV-2 human interacting proteins. We demonstrate the utility of the DCR to functionally assess SARS-CoV-2 genes and candidate human binding partners. We show that NSP8 engages in strong genetic interactions with several human candidates, most prominently with the ATE1 arginyltransferase to induce actin arginylation and cytoskeletal disorganization, and that two ATE1 inhibitors can reverse NSP8 phenotypes. The DCR enables parallel global-scale functional analysis of SARS-CoV-2 components in a prime genetic model system.

The Roles of Histone Lysine Methyltransferases in Heart Development and Disease

Epigenetic marks regulate the transcriptomic landscape by facilitating the structural packing and unwinding of the genome, which is tightly folded inside the nucleus. Lysine-specific histone methylation is one such mark. It plays crucial roles during development, including in cell fate decisions, in tissue patterning, and in regulating cellular metabolic processes. It has also been associated with varying human developmental disorders. Heart disease has been linked to deregulated histone lysine methylation, and lysine-specific methyltransferases (KMTs) are overrepresented, i.e., more numerous than expected by chance, among the genes with variants associated with congenital heart disease. This review outlines the available evidence to support a role for individual KMTs in heart development and/or disease, including genetic associations in patients and supporting cell culture and animal model studies. It concludes with new advances in the field and new opportunities for treatment.

Small molecules in the treatment of COVID-19

The outbreak of COVID-19 has become a global crisis, and brought severe disruptions to societies and economies. Until now, effective therapeutics against COVID-19 are in high demand. Along with our improved understanding of the structure, function, and pathogenic process of SARS-CoV-2, many small molecules with potential anti-COVID-19 effects have been developed. So far, several antiviral strategies were explored. Besides directly inhibition of viral proteins such as RdRp and Mpro, interference of host enzymes including ACE2 and proteases, and blocking relevant immunoregulatory pathways represented by JAK/STAT, BTK, NF-κB, and NLRP3 pathways, are regarded feasible in drug development. The development of small molecules to treat COVID-19 has been achieved by several strategies, including computer-aided lead compound design and screening, natural product discovery, drug repurposing, and combination therapy. Several small molecules representative by remdesivir and paxlovid have been proved or authorized emergency use in many countries. And many candidates have entered clinical-trial stage. Nevertheless, due to the epidemiological features and variability issues of SARS-CoV-2, it is necessary to continue exploring novel strategies against COVID-19. This review discusses the current findings in the development of small molecules for COVID-19 treatment. Moreover, their detailed mechanism of action, chemical structures, and preclinical and clinical efficacies are discussed.

SARS-CoV-2 Nsp6 damages Drosophila heart and mouse cardiomyocytes through MGA/MAX complex-mediated increased glycolysis

SARS-CoV-2 infection causes COVID-19, a severe acute respiratory disease associated with cardiovascular complications including long-term outcomes. The presence of virus in cardiac tissue of patients with COVID-19 suggests this is a direct, rather than secondary, effect of infection. Here, by expressing individual SARS-CoV-2 proteins in the Drosophila heart, we demonstrate interaction of virus Nsp6 with host proteins of the MGA/MAX complex (MGA, PCGF6 and TFDP1). Complementing transcriptomic data from the fly heart reveal that this interaction blocks the antagonistic MGA/MAX complex, which shifts the balance towards MYC/MAX and activates glycolysis-with similar findings in mouse cardiomyocytes. Further, the Nsp6-induced glycolysis disrupts cardiac mitochondrial function, known to increase reactive oxygen species (ROS) in heart failure; this could explain COVID-19-associated cardiac pathology. Inhibiting the glycolysis pathway by 2-deoxy-D-glucose (2DG) treatment attenuates the Nsp6-induced cardiac phenotype in flies and mice. These findings point to glycolysis as a potential pharmacological target for treating COVID-19-associated heart failure.

Drosophila as a Model for Human Viral Neuroinfections

The study of human neurological infection faces many technical and ethical challenges. While not as common as mammalian models, the use of Drosophila (fruit fly) in the investigation of virus–host dynamics is a powerful research tool. In this review, we focus on the benefits and caveats of using Drosophila as a model for neurological infections and neuroimmunity. Through the examination of in vitro, in vivo and transgenic systems, we highlight select examples to illustrate the use of flies for the study of exogenous and endogenous viruses associated with neurological disease. In each case, phenotypes in Drosophila are compared to those in human conditions. In addition, we discuss antiviral drug screening in flies and how investigating virus–host interactions may lead to novel antiviral drug targets. Together, we highlight standardized and reproducible readouts of fly behaviour, motor function and neurodegeneration that permit an accurate assessment of neurological outcomes for the study of viral infection in fly models. Adoption of Drosophila as a valuable model system for neurological infections has and will continue to guide the discovery of many novel virus–host interactions.

Insights from a computational analysis of the SARS-CoV-2 Omicron variant: Host-pathogen interaction, pathogenicity, and possible drug therapeutics

INTRODUCTION

Prominently accountable for the upsurge of COVID-19 cases as the world attempts to recover from the previous two waves, Omicron has further threatened the conventional therapeutic approaches. The lack of extensive research regarding Omicron has raised the need to establish correlations to understand this variant by structural comparisons. Here, we evaluate, correlate, and compare its genomic sequences through an immunoinformatic approach to understand its epidemiological characteristics and responses to existing drugs.

METHODS

We reconstructed the phylogenetic tree and compared the mutational spectrum. We analyzed the mutations that occurred in the Omicron variant and correlated how these mutations affect infectivity and pathogenicity. Then, we studied how mutations in the receptor-binding domain affect its interaction with host factors through molecular docking. Finally, we evaluated the drug efficacy against the main protease of the Omicron through molecular docking and validated the docking results with molecular dynamics simulation.

RESULTS

Phylogenetic and mutational analysis revealed the Omicron variant is similar to the highly infectious B.1.620 variant, while mutations within the prominent proteins are hypothesized to alter its pathogenicity. Moreover, docking evaluations revealed significant differences in binding affinity with human receptors, angiotensin-converting enzyme 2 and NRP1. Surprisingly, most of the tested drugs were proven to be effective. Nirmatrelvir, 13b, and Lopinavir displayed increased effectiveness against Omicron.

CONCLUSION

Omicron variant may be originated from the highly infectious B.1.620 variant, while it was less pathogenic due to the mutations in the prominent proteins. Nirmatrelvir, 13b, and Lopinavir would be the most effective, compared to other promising drugs that were proven effective.

Nucleopore Traffic Is Hindered by SARS-CoV-2 ORF6 Protein to Efficiently Suppress IFN-β and IL-6 Secretion

A weak production of INF-β along with an exacerbated release of pro-inflammatory cytokines have been reported during infection by the novel SARS-CoV-2 virus. SARS-CoV-2 encodes several proteins that are able to counteract the host immune system, which is believed to be one of the most important features contributing to the viral pathogenesis and development of a severe clinical outcomes. Previous reports demonstrated that the SARS-CoV-2 ORF6 protein strongly suppresses INF-β production by hindering the RIG-I, MDA-5, and MAVS signaling cascade. In the present study, we better characterized the mechanism by which the SARS-CoV-2 ORF6 counteracts IFN-β and interleukin-6 (IL-6), which plays a crucial role in the inflammation process associated with the viral infection. In the present study, we demonstrated that the SARS-CoV-2 ORF6 protein has evolved an alternative mechanism to guarantee host IFN-β and IL-6 suppression, in addition to the transcriptional control exerted on the genes. Indeed, a block in movement through the nucleopore of newly synthetized messenger RNA encoding the immune-modulatory cytokines IFN-β and IL-6 are reported here. The ORF6 accessory protein of SARS-CoV-2 displays a multifunctional activity and may represent one of the most important virulence factors. Where conventional antagonistic strategies of immune evasion-such as the suppression of specific transcription factors (e.g., IRF-3, STAT-1/2)-would not be sufficient, the SARS-CoV-2 ORF6 protein is the trump card for the virus, also blocking the movement of IFN-β and IL-6 mRNAs from nucleus to cytoplasm. Conversely, we showed that nuclear translocation of the NF-κB transcription factor is not affected by the ORF6 protein, although inhibition of its cytoplasmic activation occurred. Therefore, the ORF6 protein exerts a 360-degree inhibition of the antiviral response by blocking as many critical points as possible.

ACE and ACE2: insights from Drosophila and implications for COVID-19

Angiotensin-converting enzyme (ACE) and its homologue ACE2 are key regulators of the renin-angiotensin system and thereby cardiovascular function through their zinc-metallopeptidase activity on vasoactive peptides. ACE2 also serves as the receptor for the cellular entry of various coronaviruses including the severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), which is responsible for the coronavirus disease 2019 (COVID-19). The unprecedented scale of the COVID-19 pandemic has spurred the use of mammalian models to investigate the SARS-ACE2 relationship and knowledge gained from such research has accelerated development of vaccines and therapeutics. Recent studies have just started to underscore the utility of the fruit fly Drosophila melanogaster as a model system to study virus-host interactions and pathogenicity. Notably, the remarkable existence of catalytically functional ACE and ACE2 orthologues in Drosophila, discovered more than two decades ago, provides a unique opportunity for further developing this model organism to better understand COVID-19 in addition to identifying coronavirus preventative and therapeutic interventions targeting ACE2. Here, we review the studies that revealed crucial insights on the biochemistry and physiology of Ance and Acer, two out of the six Drosophila ACE family members with the greatest homology to human ACE and ACE2. We highlight shared in vivo functions outside of the renin-angiotensin system, which is not conserved in flies. Importantly, we identify knowledge gaps that can be filled by further research and outline ways that can raise Drosophila to a powerful model system to combat SARS-CoV-2 and its threatening vaccine-evading variants.

Programmed Cell Death in SARS-CoV-2 Infection: A Short Review

Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), the latest variant in the coronavirus family, causing COVID-19, has resulted in global pandemic since early 2020 leading to severe public health concern. So far, the pandemic has caused more than 200 million infections and 4 million deaths worldwide. Most of the studies are focused on developing prevention, intervention, and therapeutic strategies. However, underlying pathophysiology of the disease is important as well, which needs further attention. Cell death is one of the major causative mechanisms that leads to severe inflammation, and it is also an a posteriori consequence of the hyperinflammatory storm that renders poor prognosis of the disease. Substantial cell death has been reported in biopsy samples from post mortem patients. Among the distinct cell death pathways, apoptosis, the regulated programmed cell death plays an important role in the pathogenesis of the disease. Understanding the role of SARS-CoV-2 infection in apoptosis is critical to linearize the pathogenesis of the virus as well as the resultant disease, that may uncover novel therapeutic targets in treatment of COVID-19 patients. Here, we review the current progress on the underlying molecular mechanism(s) of SARS-CoV-2-induced apoptosis, not only at the level of the virus but also at its individual proteins.

Entropy and Fractal Dimension Study of the TDP-43 Protein Low Complexity Domain Sequence in ALS Disease Severity and SARS-CoV-2 Gene Sequences in Virulence Variability

The low complexity domain (LCD) sequence has been defined in terms of entropy using a 12 amino acid sliding window along a protein sequence in the study of disease-related genes. The amyotrophic lateral sclerosis (ALS)-related TDP-43 protein sequence with intra-LCD structural information based on cryo-EM data was published recently. An application of entropy and Higuchi fractal dimension calculations was described using the Znf521 and HAR1 sequences. A computational analysis of the intra-LCD sequence entropy and Higuchi fractal dimension values at the amino acid level and at the ATCG nucleotide level were conducted without the sliding window requirement. The computational results were consistent in predicting the intermediate entropy/fractal dimension value produced when two subsequences at two different entropy/fractal dimension values were combined. The computational method without the application of a sliding-window was extended to an analysis of the recently reported virulent genes—Orf6, Nsp6, and Orf7a—in SARS-CoV-2. The relationship between the virulence functionality and entropy values was found to have correlation coefficients between 0.84 and 0.99, using a 5% uncertainty on the cell viability data. The analysis found that the most virulent Orf6 gene sequence had the lowest nucleotide entropy and the highest protein fractal dimension, in line with extreme value theory. The Orf6 codon usage bias in relation to vaccine design was discussed.

Understanding individual SARS-CoV-2 proteins for targeted drug development against COVID-19

Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) is the cause of the COVID-19 pandemic, responsible for millions of deaths globally. Even with effective vaccines, SARS-CoV-2 will likely maintain a hold in the human population through gaps in efficacy, percent vaccinated, and arising new strains. Therefore, understanding how SARS-CoV-2 causes widespread tissue damage and the development of targeted pharmacological treatments will be critical in fighting this virus and preparing for future outbreaks. Herein, we summarize the progress made thus far by using in vitro or in vivo models to investigate individual SARS-CoV-2 proteins and their pathogenic mechanisms. We have grouped the SARS-CoV-2 proteins into three categories: host entry, self-acting, and host interacting. This review focuses on the self-acting and host-interacting SARS-CoV-2 proteins and summarizes current knowledge on how these proteins promote virus replication and disrupt host systems, as well as drugs that target the virus and virus interacting host proteins. Encouragingly, many of these drugs are currently in clinical trials for the treatment of COVID-19. Future coronavirus outbreaks will most likely be caused by new virus strains that evade vaccine protection through mutations in entry proteins. Therefore, study of individual self-acting and host-interacting SARS-CoV-2 proteins for targeted therapeutic interventions is not only essential for fighting COVID-19 but also valuable against future coronavirus outbreaks.

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

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.