Macrophage migration inhibitory factor is a valid drug target at the intersection of herpes simplex virus 1 replication and Alzheimer's disease-relevant cellular pathology
The viral life cycle usurps host cellular factors, redirecting them from physiological functions to viral needs thereby revealing their "moonlighting" functions, disturbing cellular proteostasis, and increasing risk of specific, virus-associated protein misfolding diseases (PMD). Identifying such virus-repurposed host proteins therefore allow study of fundamental cellular events leading to associated "sporadic" PMD. Here, we identified a small molecule with unprecedented activity against neurotropic herpes simplex virus 1 (HSV-1) modulating an allosteric site of Macrophage Migration Inhibitory Factor (MIF). The compound efficiently reduced HSV-1-mediated tau phosphorylation or aggregation in vitro and in vivo, even without HSV-1 infection. The lead compound specifically interacted with an oxidized conformer of MIF (oxMIF) from either recombinant MIF or post-mortem brain homogenates of patients with Alzheimers disease (AD). OxMIF thus participates in a host-viral interface connecting HSV-1 infection, and possibly other external stressors, with tau cellular pathology characteristic for PMD, including Alzheimes disease.