Suppression of SARS‐CoV‐2 infection in ex‐vivo human lung tissues by targeting class III phosphoinositide 3‐kinase

Abstract

The novel betacoronavirus severe acute respiratory syndrome coronavirus 2 (SARS‐CoV‐2) emerged at the end of 2019 and caused the coronavirus disease 19 (COVID‐19) pandemic due to its high transmissibility and early immunosuppression. Previous studies on other betacoronaviruses suggested that betacoronavirus infection is associated with the host autophagy pathway. However, it is unclear whether any components of autophagy or virophagy can be therapeutic targets for COVID‐19 treatment. In this report, we examined the antiviral effect of four well‐characterized small molecule inhibitors that target the key cellular factors involved in key steps of the autophagy pathway. They include small molecules targeting the ULK1/Atg1 complex involved in the induction stage of autophagy (ULK1 inhibitor SBI0206965), the ATG14/Beclin1/VPS34 complex involved in the nucleation step of autophagy (class III PI3‐kinase inhibitor VPS34‐IN1), and a widely‐used autophagy inhibitor that persistently inhibits class I and temporary inhibits class III PI3‐kinase (3‐MA) and a clinically approved autophagy inhibitor that suppresses autophagy by inhibiting lysosomal acidification and prevents the formation of autophagolysosome (HCQ). Surprisingly, not all the tested autophagy inhibitors suppressed SARS‐CoV‐2 infection. We showed that inhibition of class III PI3‐kinase involved in the initiation step of both canonical and noncanonical autophagy potently suppressed SARS‐CoV‐2 at a nano‐molar level. In addition, this specific kinase inhibitor VPS34‐IN1, and its bioavailable analogue VVPS34‐IN1, potently inhibited SARS‐CoV‐2 infection in ex vivo human lung tissues. Taken together, class III PI3‐kinase may be a possible target for COVID‐19 therapeutic development.

Dissecting lipid metabolism alterations in SARS-CoV-2

“…Furthermore, inhibition of class III phosphoinositide 3-kinase (PI3K), the enzyme that produces PtdIns3P from PtdIns, has been shown to potently inhibit SARS-CoV-2 infection of human lung model ex vivo [ 39 ]. Similarly, class I PI3K inhibition has been shown to affect SARS-CoV-2 replication [ 40 ].…”

Pharmacological Modulators of Autophagy as a Potential Strategy for the Treatment of COVID-19

“…Regarding specifically to CoVs, the PI3K inhibitor wortmannin inhibited MERS-CoV infection in Huh7 cells [ 61 ] and reduced vesicle formation in HEK cells that express infectious bronchitis virus (IBV) nsp6, thus indicating that nsp6-induced autophagy was dependent on PI3K [ 84 ]. Likewise, the inhibition of PI3K with VPS34-IN1 in Vero E6 cells and its bioavailable analogue VPS34-IN1 in ex vivo human lung tissues potently suppressed SARS-CoV-2 replication at a nanomolar level [ 189 ]. Moreover, the pharmacological inhibition of E3 ubiquitin ligase, a component of SKP2, decreased the ubiquitination and degradation of Beclin-1 and enhanced autophagic flux, consequently reducing MERS-CoV replication [ 60 ].…”

Taming the Autophagy as a Strategy for Treating COVID-19

“…Theoretical calculations and practical experimentation alike will be required to develop this technology. [103,104,[196][197][198][199] Spermidine Activator…”

“…Conclusive studies are still lacking, but potent in vitro inhibition of SARS-CoV-2 replication was recently reported for VPS34-IN1 and VVPS34-IN1 and their analogues, which are inhibitors of vacuolar protein sorting (VPS) 34 (a class III phosphoinositol-3 kinase, PI3K). These inhibitors block autophagy [ 103 , 104 ].…”

“…Among the inhibitors of PI3K commonly employed to block autophagy are 3-methyladenine [ 192 ], wortmannin, LY294002 [ 193 ], PT210 [ 194 ] and GSK-2126458 [ 195 ]. Inhibitors of VPS34 (a PI3K) are VPS34-IN1 and VVPS34-IN1 [ 103 , 104 ], which have antiviral properties against SARS-CoV-2. The analogues of these inhibitors should also be investigated: Spautin-1 [ 196 ], SAR405 [ 197 ], compound 31 [ 198 ] and PIK-III [ 199 ].…”