A virus that reproduces in a host without killing cells can easily establish a successful infection. Previously, we showed that dengue-2, a virus that threatens 40% of the world, induces autophagy, enabling dengue to reproduce in cells without triggering cell death. Autophagy further protects the virus-laden cells from further insults. In this study, we evaluate how it does so; we show that dengue upregulates host pathways that increase autophagy, namely endoplasmic reticulum (ER) stress and ataxia telangiectasia mutated (ATM) signaling followed by production of reactive oxygen species (ROS). Inhibition of ER stress or ATM signaling abrogates the dengue-conferred protection against other cell stressors. Direct inhibition of ER stress response in infected cells decreases autophagosome turnover, reduces ROS production and limits reproduction of dengue virus. Blocking ATM activation, which is an early response to infection, decreases transcription of ER stress response proteins, but ATM has limited impact on production of ROS and virus titers. Production of ROS determines only late-onset autophagy in infected cells and is not necessary for dengue-induced protection from stressors. Collectively, these results demonstrate that among the multiple autophagy-inducing pathways during infection, ER stress signaling is more important to viral replication and protection of cells than either ATM or ROS-mediated signaling. To limit virus production and survival of dengue-infected cells, one must address the earliest phase of autophagy, induced by ER stress.

Influenza virus causes infected cells to generate large numbers of lipid droplets. Because the virus envelope contains substantial cholesterol, we applied atorvastatin (ATV) to Madin‐Darby Canine Kidney cells before infecting them. Five micromolars ATV, within physiologic range, strongly (>95%) inhibits reproduction of influenza A as measured by PCR of viral RNA, plaque assay for viable virus, and production of virus nucleoprotein (NP). Inhibition of any of the following can suppress formation of lipid droplets (>−50%) but does not interfere with the production of NP: endoplasmic reticulum stress, autophagy, or production of reactive oxygen substances (ROS). We conclude that, regardless of whether this widely used statin, which is generally considered to be safe, can prevent infection or minimize its severity, inhibition of the 3‐hydroxy‐3‐methylglutaryl‐coenzyme A reductase pathway to protect against infection by influenza virus or to mitigate its severity warrants further exploration.—Episcopio, D., Aminov, S., Benjamin, S., Germain, G., Datan, E., Landazuri, J., Lockshin, R. A., Zakeri, Z. Atorvastatin restricts the ability of influenza virus to generate lipid droplets and severely suppresses the replication of the virus. FASEB J. 33, 9516–9525 (2019). http://www.fasebj.org

Background: Cells taken from mouse embryos before sex differentiation respond to insults according to their chromosomal sex, a difference traceable to differential methylation. We evaluated the mechanism for this difference in the controlled situation of their response to ethanol. Methods: We evaluated the expression of mRNA for alcohol dehydrogenase (ADH), aldehyde dehyrogenases (ALDH), and a cytochrome P450 isoenzyme (Cyp2e1) in male and female mice, comparing the expressions to toxicity under several experimental conditions evaluating redox and other states. Results: Females are more sensitive to ethanol. Disulfiram, which inhibits alcohol dehydrogenase (ADH), increases cell death in males, eliminating the sex dimorphism. The expressions ADH Class 1 to 4 and ALDH Class 1 and 2 do not differ by sex. However, females express approximately 8X more message for Cyp2e1, an enzyme in the noncanonical pathway. Female cells produce approximately 15% more ROS (reactive oxygen species) than male cells, but male cells contain approximately double the concentration of GSH, a ROS scavenger. Scavenging ROS with Nacetyl cysteine reduces cell death and eliminates sex dimorphism. Finally, since many of the differences in gene expression derive from methylation of DNA, we exposed cells to the methyltransferase inhibitor 5-aza-2deoxycytidine; blocking methylation eliminates both the difference in expression of Cyp2e1 and cell death. Conclusion: We conclude that the sex-differential cell death caused by ethanol derives from sex dimorphic methylation of Cyp2e1 gene, resulting in generation of more ROS.