Dynasore enhances the formation of mitochondrial antiviral signalling aggregates and endocytosis‐independent NF‐κB activation

Abstract

BACKGROUND AND PURPOSEDynasore has been used extensively as an inhibitor of clathrin-mediated endocytosis. While studying the role of endocytosis in LPS-induced signalling events, we discovered that dynasore itself induced activation of NF-κB, independently of its effects on endocytosis and without involving the Toll-like receptor 4 signalling pathways. The purpose of this study was to characterize this novel effect and to explore the underlying mechanism of action. EXPERIMENTAL APPROACHWe utilized gel electrophoresis, microscopy, gene knockdown and luciferase-based promoter activity to evaluate the effect of dynasore on cell signalling pathways and to delineate the mechanisms involved in its effects, KEY RESULTSDynasore activated the NF-κB and IFN-β pathways by activating mitochondrial antiviral signalling protein (MAVS). We showed that MAVS is activated by NOX/Rac and forms high molecular weight aggregates, similar to that observed in response to viral infection. We also demonstrated that dynasore-induced activation of JNK occurs downstream of MAVS and is required for activation of NF-κB and IFN-β. CONCLUSION AND IMPLICATIONSThese findings demonstrate a novel effect of dynasore on cell signalling. We describe a novel Rac1-, ROS-and MAVS-mediated signalling cascade through which dynasore dramatically activates NF-κB, mimicking the viral induction of this key inflammatory signalling pathway. Our results call attention to the need for a broader interpretation of results when dynasore is used in its traditional fashion as an inhibitor of clathrin-mediated endocytosis. These results suggest the intriguing possibility that dynasore or one of its analogues might be of value as an antiviral therapeutic strategy or vaccine adjuvant.Abbreviations CME, clathrin-mediated endocytosis; DRP1, dynamin-related protein 1; MAVS, mitochondrial anti-viral signalling; MFN, mitofusin; ROS, reactive oxygen species; SAPK, stress-activated PK (JNK2); TLR4, Toll-like receptor 4

Activation of the Anti-Oxidative Stress Response Reactivates Latent HIV-1 Through the Mitochondrial Antiviral Signaling Protein Isoform MiniMAVS

“…As shown in Figure 1D, Dynasore induced viral reactivation in latently infected 2D10 cells in a dose-dependent manner, reaching a plateau at 12.5 µM. Dynasore has been shown to activate NF-kB through the induction of ROS and subsequent activation of MAVS (32). We confirmed that viral reactivation mediated by Dynasore was dependent on NF-kB.…”

“…Besides its ability to inhibit dynamin-related processes, Dynasore has other activities that are independent of dynamin (30,31). In particular, Dynasore induces activation of the transcription factor NF-kB by activating the mitochondrial antiviral signaling protein (MAVS) (32). This process is mediated by the generation of reactive oxygen species (ROS), and it is independent of Dynasore's ability to inhibit endocytosis.…”

Dynamin-2 mutations linked to Centronuclear Myopathy impair actin-dependent trafficking in muscle cells

“…3 ), we cannot discard the possibility that these pharmacological agents have off-target effects on actin polymerization. In this regard, dynasore per se has been shown to influence F-actin stability 41 and Rac activation 42 . Hence, it is possible that dynasore disrupts actin polymerization in RCMH myoblasts in a way that not only depends on dynamin inhibition.…”

Molecular docking and simulation studies on SARS-CoV-2 Mpro reveals Mitoxantrone, Leucovorin, Birinapant, and Dynasore as potent drugs against COVID-19

“…Dynasore is known as GTPase inhibitor, which prevents endocytosis by rapidly inhibiting Dynamin activity (Preta et al, 2015). Also, the antiviral activity of Dynasore against the dengue virus (DENV) (Carro et al, 2018) and it is showing a vaccine adjuvant or antiviral therapeutic strategy by activating mitochondrial antiviral signaling protein (Ailenberg et al, 2015). Figure 4(a) shows, the binding mode of Birinapant within the SARS-CoV-2 M pro cavity.…”