The coronavirus disease-2019 (COVID-19) pandemic, caused by severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), has infected more than 116 million individuals globally and resulted in over 2.5 million deaths since the first report in December 2019. For most of this time, healthcare professionals have had few tools at their disposal. In December 2020, several vaccines that were shown to be highly effective have been granted emergency use authorization (EUA). Despite these remarkable breakthroughs, challenges include vaccine roll-out and implementation, in addition to deeply entrenched antivaccination viewpoints. While vaccines will prevent disease occurrence, infected individuals still need treatment options, and repurposing drugs circumvents the lengthy and costly process of drug development. SARS-CoV-2, like many other enveloped viruses, require the action of host proteases for entry. In addition, this novel virus employs a unique method of cell exit of deacidified lysosomes and exocytosis. Thus, inhibitors of lysosomes or other players in this pathway are good candidates to target SARS-CoV-2. Chemical compounds in the quinoline class are known to be lysomotropic and perturb pH levels. A large number of quinolines are FDA-approved for treatment of inflammatory diseases and antimalarials. Artemisinins are another class of drugs that have been demonstrated to be safe for use in humans and are widely utilized as antimalarials. In this Review, we discuss the use of antimalarial drugs in the class of quinolines and artemisinins, which have been shown to be effective against SARS-CoV-2 in vitro and in vivo , and provide a rationale in employing quinolines as treatment of SARS-CoV-2 in clinical settings.

Chikungunya virus (CHIKV) is a re-emerging arbovirus in the alphavirus genus. Upon infection, it can cause severe joint pain that can last years in some patients, significantly affecting their quality of life. Currently, there are no vaccines or anti-viral therapies available against CHIKV. Its spread to the Americas from the eastern continents has substantially increased the count of the infected by millions. Thus, there is an urgent need to identify therapeutic targets for CHIKV treatment. A potential point of intervention is the sphingosine-1-phosphate (S1P) pathway. Conversion of sphingosine to S1P is catalyzed by Sphingosine kinases (SKs), which we previously showed to be crucial pro-viral host factor during CHIKV infection. In this study, we screened inhibitors of SKs and identified a novel potent inhibitor of CHIKV infection—SLL3071511. We showed that the pre-treatment of cells with SLL3071511 in vitro effectively inhibited CHIKV infection with an EC50 value of 2.91 µM under both prophylactic and therapeutic modes, significantly decreasing the viral gene expression and release of viral particles. Our studies suggest that targeting SKs is a viable approach for controlling CHIKV replication.

Background Over 43% of the world's population regularly consumes alcohol. Although not commonly known, alcohol can have a significant impact on the respiratory environment. Living in the time of the COVID‐19 pandemic, alcohol misuse can have a particularly deleterious effect on SARS‐CoV‐2‐infected individuals and, in turn, the overall healthcare system. Patients with alcohol use disorders have higher odds of COVID‐19‐associated hospitalization and mortality. Even though the detrimental role of alcohol on COVID‐19 outcomes has been established, the underlying mechanisms are yet to be fully understood. Alcohol misuse has been shown to induce oxidative damage in the lungs through the production of reactive aldehydes such as malondialdehyde and acetaldehyde (MAA). MAA can then form adducts with proteins, altering their structure and function. One such protein is surfactant protein D (SPD), which plays an important role in innate immunity against pathogens. Methods and Results In this study, we examined whether MAA adduction of SPD (SPD‐MAA) attenuates the ability of SPD to bind SARS‐CoV‐2 spike protein, reversing SPD‐mediated virus neutralization. Using ELISA, we show that SPD‐MAA is unable to competitively bind spike protein and prevent ACE2 receptor binding. Similarly, SPD‐MAA fails to inhibit entry of wild‐type SARS‐CoV‐2 virus into Calu‐3 cells, a lung epithelial cell line, as well as ciliated primary human bronchial epithelial cells isolated from healthy individuals. Conclusions Overall, MAA adduction of SPD, a consequence of alcohol overconsumption, represents one mechanism of compromised lung innate defense against SARS‐CoV‐2, highlighting a possible mechanism underlying COVID‐19 severity and related mortality in patients who misuse alcohol.

Sphingosine kinase 2 (SK2) is a lipid kinase that catalyzes the production of sphingosine-1-phosphate (S1P) from sphingosine. Previously, we have shown that SK2 is recruited to the viral replication complex (VRC) early during chikungunya virus (CHIKV) infection. In the present study, we demonstrate that SK2 is required for viral replication and protein production. Treatment with a SK2 inhibitor significantly impaired the function of a CHIKV replicon. Similarly, compound treatment or genetic targeting resulted in impaired viral protein production. Mechanistically, we demonstrate that CHIKV nsP3 binds to SK2. Association of nsP3 with SK2 was mediated, in part, through the FGDF motifs within the hypervariable domain (HVD) of nsP3. In a competition assay, SK2 competed with G3BP for binding to nsP3. Collectively, these results extend our previous findings and identify SK2 as a CHIKV host factor recruited by nsP3.