A novel small molecule inhibitor of human Drp1

Abstract

Mitochondrial dynamin-related protein 1 (Drp1) is a large GTPase regulator of mitochondrial dynamics and is known to play an important role in numerous pathophysiological processes. Despite being the most widely used Drp1 inhibitor, the specificity of Mdivi-1 towards human Drp1 has not been definitively proven and there have been numerous issues reported with its use including off-target effects. In our hands Mdivi-1 showed varying binding affinities toward human Drp1, potentially impacted by compound aggregation. Herein, we sought to identify a novel small molecule inhibitor of Drp1. From an initial virtual screening, we identified DRP1i27 as a compound which directly bound to the human isoform 3 of Drp1 via surface plasmon resonance and microscale thermophoresis. Importantly, DRP1i27 was found to have a dose-dependent increase in the cellular networks of fused mitochondria but had no effect in Drp1 knock-out cells. Further analogues of this compound were identified and screened, though none displayed greater affinity to human Drp1 isoform 3 than DRP1i27. To date, this is the first small molecule inhibitor shown to directly bind to human Drp1.

Evaluation of the efficacy of mitochondrial fission inhibitor (Mdivi-1) using non-alcoholic steatohepatitis (NASH) liver organoids

“…Rosdah et al identified a novel small molecule inhibitor of Drp1 (Drp1i27) that could directly bind to the human isoform 3 of Drp1 and increase the cellular networks of fused mitochondria in a dose-dependent way without any effects in Drp1 knock-out cells ( Rosdah et al, 2022 ). It showed cytoprotective potentials in human fibroblasts exposed to oxidative stress, HL-1 cells with ischemia-reperfusion damage, and human iPSC-derived cardiomyocytes with doxorubicin-induced cytotoxicity ( Rosdah et al, 2022 ). Thus Drp1i27 might be a promising alternative to Mdivi1 for the inhibition of Drp1 .…”

Mitophagy for cardioprotection

“…However, caution must be exercised in utilizing these interventions since many molecules have multiple cellular functions and their effects are context dependent. For example, the effect of Mdivi-1, a chemical inhibitor of Drp1, upon I/R injury is dose and context dependent [ 148 , 222 ]. Myocardial ischemia without reperfusion activates not only conventional mitophagy but also alternative mitophagy in the heart [ 152 ].…”

Discovery of Potent Allosteric DRP1 Inhibitors by Disrupting Protein–Protein Interaction with MiD49

“…Structurally, Drpitor1 is an analogue of ellipticine, a known DNA intercalator, and its applicability beyond oncology has yet to be fully explored. DRP1i27 is a human DRP1 isoform 3 binder with modest affinity binding to GTPase site of DRP1 . The DRP1 inhibitors previously reported by Mitobridge were selective uncompetitive inhibitors of GTPase activity and served as unique tool compounds for exploring the roles of mitochondrial division in cells and assessing the potential therapeutic utility .…”

“…DRP1i27 is a human DRP1 isoform 3 binder with modest affinity binding to GTPase site of DRP1. 11 inhibitors previously reported by Mitobridge were selective uncompetitive inhibitors of GTPase activity and served as unique tool compounds for exploring the roles of mitochondrial division in cells and assessing the potential therapeutic utility. 12 However, these compounds did not exhibit a significant mitochondrial morphology change in cells, which limited its application.…”

“…Multiple small molecule DRP1 inhibitors have been reported in the literature including mdivi-1, Drpitor1, DRP1i27, and DRP1 GTPase inhibitors . Mdivi-1 is widely reported to inhibit DRP1-dependent fission, elongate mitochondria, and mitigate brain injury.…”